Note: Descriptions are shown in the official language in which they were submitted.
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PRINTING APPARATUS
I
Back~round of the Invention
1. Field of the Invention
The present invention is concerned with a
greatly improved imprinting device capable of
printing at very high speeds permitting the device
to be used as a machine printer, while at the same
time being sufficiently simple and low in cost
that it can be employed as a conventional type-
writer in a home or office. More particularly, it
is concerned with such a device which accomplishes
printing, word spacing and tab spacing using a
single mainspring as a source of motive energy and
in such manner that a limited energy quantum is
withdrawn from the mainspring and distributed
during each printing and/or spacing cycle in the
most efficient manner. Energy distribution is
effected such that energy remaining after the
required energy for actual printing purposes is
determined is employed to increase the speed of
translation along the page; in this way a variable
but statistically very high printing speed i9
obtained.
2. Description of the Prior Art
- The typewriter art is highly developed
and over a century old. At the outset of type-
writer development, the devices were for the mostpart strictly mechanical typewriting machines of
various degrees of complexity and sophistication.
In more recent times these mechanical or manual
machines have been largely replaced by electri-
cally powered typewriters. In all cases however,
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1 the goal has been to achieve sufficient typingspeed along with consistently good printing quali-
ties.
With the advent of the electronic age,
and particularly the development of high speed
computers and information processing equipment, a
need arose for a printing device having capa-
bilities greatly different from those required of
a conventional manual or electric typewriter. For
example, while a fifteen character per second
typing speed is more than adequate for a type-
writer, this rate is exceedingly slow when con-
- trasted with the output rates of computers or the
like. In response to the need for high speed
printing devices, a number of units have been
proposed. Among these are dot printers, ink jet
printers, chain printers, laser printers, daisy
printers, modified electric typewriter printers,
line printers and xerographic printers. While a
number of these devices have achieved substantial
commercial success for their intended function,
they are in general characterized by a high degree
of mechanical, electric and/or electronic com-
plexity, and concomitant high cost. Further, most
Of these units are simply not realistically usable
as a typewriter, inasmuch as they have poor print-
ing quality, obscure the line of write as printing
proceeds, or are incapable of making carbon
copies.
In short, conventional manual or elec-
tric typewriters are adequate for normal type-
writing and can be purchased at a reasonable cost,
but are too slow or too expensive to convert to
machine printers; on the other hand, printers
~eveloped specifically for coupling to remote
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1 input from computers, magnetic recordings, phonç
couplings or the like are ~n general far too
expensive to justify use thereof as a typewriter,
~ even if this were a functional possibility.
! ~ The problems outlined above have pre-
sented a serious obstacle to the spread of small
computers and remote terminals linked to large
central computers. Thus, while an individual or
small company may be willing to invest in a small
computer or terminal, the cost of a conventional
machine printer as a part thereof may be such as
to make the package price prohibitive. On the
other hand, if a low cost typewriter/printer were
available, the effect upon the spread of computer
technology and other data processing equipment
would be considerable.
Hence, there is a real and heretofore
unsatisfied need in the art for a low cost, high
speed printing device usable without modification
either as a conventional typewriter or machine
; printer.
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Summary of the Invention
The present invention overcomes the
problems noted above and provides a simplified,
extremely low cost, high speed printing apparatus
which can be interchangeably used without modifi-
cation thereof as a normal typewriter or machine
printer. To this end, the apparatus hereof is
provided with a compact carriage assembly shift-
able relative to a page or the like to be printed
and carrying novel printing mear.s. The functions
of character printing and spacing (both letter-
spacing and tab spacing) are activated and ac-
complished using quanta of potential energy stored
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1 in a single, windable mainspring likewise carried
on the carriage. The appanatus of the invention
is designed such that variable but very high
carriage translation speeds can be attained, in
order-~hat the resultant typing speed is likewise
very high for an impact printer (e.g., fifty
characters per second or more depending upon
text). At the same time, printing characteristics
are uniform regardless of carrier speed or vari-
ances therein.
In more detail, the preferred form ofthe invention includes printing structure com-
prising printing means, and means (e.g., a rack
and gear assembly2 for effecting relative trans-
latory movement between the printing means and thepage being printed upon. The printing means has a
shiftable, lightweight, distensible, shape-re-
taining band including a series of printing charac-
ters thereon, along with a selectively shiftable,
over center impact member or hammer for engaging
and distending the band towards the page for
printing purposes. During each printing cycle,
the hammer consumes a constant amount of energy,
independent of carriage translation speed, in
2S order to give consistent printing characteristics.
On the other hand, the amount of energy consumed
in the character selection process is variable and
dependent upon the distance the band must shift in
a given cycle. Thus, the total motive energy
required by the printing means is variable.
An energy distributing transmission
assembly couples the printing means and transla-
tion means. The transmission assembly serves to
mechanically couple the printing means and trans-
lation means in parallel, and includes appropriate
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1 geari~g for withdrawing a limited quantity of
energy from the mainspringlduring each printing or
spacing cycle, and for distributing this energy
between the printing means and the translation
means. Energy distribution is effected such that
operation of the printing and translation means is
commenced simultaneously and, after the total
amount of energy required by the printing means is
determined by the extent of band spin, remaining
1~ energy of the limited amount is expended in car-
riage movement. Thus when relatively little
energy is consumed by band spin, carriage speed
increases; conversely, when head spin consumes
relatively more energy, carriage speed decreases.
From a statistical standpoint however, average
carriage speed in a given line of write is very
high, thereby permitting use of the present in-
vention as a machine printer.
During wordspacing or tab spacing
cycles, the hammer is disengaged and no portion of
the limited energy amount is expended on hammer
movement. Sùch excess energy is supplied to the
translation means with the effect that spacing
speed is very high. In order to prevent the
carriage from attaining very high, potentially
destructive speeds during tab spacing, the band is
spun during this operation and serves as a type of
airfoil governor for limiting carriage translation
speed.
Control for the printing structure of
the invention is achieved through use of only two
selectively operable solenoids, along with oper-
ating linkages connecting the solenoids and trans-
mission assembly. Appropriate logic circuitry
couples the solenoids and band position sensors
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-1 with the keyboard or other input, in order to send
control signals to the solenoids in response and
corresponding to selection of a character to be
printed or space to be formed.
Brief Description of the Drawings
Figure 1 is a plan view of a typewriter/
printer in accordance with the invention;
Fig. 2 is a fragmentary sectional view
taken along line 2-2 of Fig. 1 which illustrates
the details of construction of the shiftable
carriage;
Fig. 3 is a sectional view taken along
- line 3-3 of Fig. 2;
Fig. 4 is a fragmentary sectional view
illustrating portions of the gear transmission
coupled between the mainspring and printing ~eans
of the invention;
Fig. 5 is a bottom view illustrating the
energy-storing mainspring and the coupling thereof
to the carriage-translating gear and rack assembly;
Fig; 6 is a fragmentary view taken
substantially along the center line of the carriage
assembly, with portions of the structure depicted
in elevation and other portions in sections;
, Fig. 7 is a view similar to that of Fig.
2 but illustrating the internal construction of
the carriage assembly, viewed from the side oppo-
site that of Fig. 2;
Fig. 8 is a fragmentary view in partial
section illustrating the upper head portion of the
carriage assembly;
Fig. 9 is an enlarged, fragmentary view
illustrating the character printing operation
wherein the impact hammer engages the distensible,
117(~6C~0
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l character-bearing band and distends the same
towards a page for printin~ purposes;
Fig. 10 is a sectional view taken along
line 10~10 of Fig. 9 which further illustrates the
construction of the character-bearing band and
impact hammer;
Fig. 11 is a fragmentary plan view of
the distensible character-bearing band;
Fig. 12 is a fragmentary elevational
view of the band depicted in-Fig. 11;
Fig. 13 is a sectional view taken along
13-13 of Fig. 12;
Fig. 14 is an elevational view similar
to that of Fig. 12 but depicting the opposite side
of the band;
Fig. 15 is a view similar to that of
Fig. 3 but illustrating the operation of the
printing means during a character-printing cycle;
Fig. 16 is a fragmentary sectional view
depicting the orientation of the hammer drive
assembly during the character-printing cycle
illustrated in Fig. 15;
Fig. 17 is a fragmentary sectional view
illustrating the orientation of the upright,
movement-stopping tine in the release position
thereof;
Fig. 18 is a fragmentary view similar to
that of Fig. 15, but illustrating the operation of
the printing means during letter or tab spacing
cyclesi
Fig. 19 is a sectional view similar to
that of Fig. 16, and depicting the operation of
the hammer drive assembly during the spacing cycle
depicted in Fig. 18;
Fi~. 20 is a schematic, exploded view
.
117(~66~!0
1 illust~ating the energy transmission and distri-
bution^structure of the in~ention; and
Fig. 21 is a diagram, partially in block
' form and partially in schematic form, illustrating
i 5 an exemplary type of electrical control circuitry
for use wit'n the invention.
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1 Description of the Preferred Embodiment
~ Turning now to t~e drawings, a printing
apparatus 30 in accordance with the invention is
illustrated in plan in Fig. 1. Broadly speaking,
the apparatus 30 includes a conventional external
casing 32, a multiple key keyboard 34 of known
construction, an elongated, axially rotatable
platen 36, and printing structure broadly referred
by the numeral 38.
Casing 32 includes respec~ive upright
sidewalls 40, 42, an apertured, forward keyboard-
receiving wall 44, and respective, elongated,
spaced apart upper walls 46, 48 which coopera-
tively define an elongated, substantially rec-
tangular opening therebetween for receiving platen
36 and printing structure 38.
Keyboard 34 is of the usual type and in-
cludes the necessary number of character selection
keys 50, a single spacing bar 52, left and right
shift keys 54, 56, a shift lock key 58, a tab
spacing key 60, a backspacing key 62, a carriage
return key 64, and, if desired, a separate paper
advance or line feed key 65. As illustrated, the
various operational keys are oriented in the usual
manner, in order that apparatus 30 can be used as
a normal typewriter. It will also become apparent
in the ensuing discussion that other varieties of
keyboards can be used in the apparatus of the
present invention.
Platen 36 includes an elongated, cylin-
drical, rigid roller 66 having a pair of radially
; enlarged, endmost elements 68, 70. The platen 36
is mounted between sidewalls 40, 42 for axial
rotation thereof. In addition, an elongated,
arcuate, shiftable, paper guide 72 extends par-
tially around roller 66 from wall 48 towards the
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l forw~rd region of the roller. The guide 72 carries
a pair of elongated, papertengaging rollers 74,
76, as is usual in constructions of this type.
Guide 72 and the associated rollers 74, 76 are
shiftable to a limited extent by the operator when
the paper release lever (not shown) is actuated.
Printing structure 38 includes a carriage
assembly 78, a selectively operable electric motor
80, and an elongated cable 82 operably coupling
motor 80 and carriage assembly 78. Motor 80 is of
conventional construction and includes a rotatable
output spool 84 which rotates in a clockwise
direction upon actuation of motor 80. -The cable
82 is secured to spool 84 for windup thereon, and
is threaded about a guide pulley 86 mounted on
sidewall 40 (see Fig. 1). The remaining end of
cable 82 is operatively secured to the carriage
assembly 78 in a manner to be made clear herein-
after.
Z0 Carriage assembly 78 broadly includes a
housing 88 which is substantially rectangular in
plan configuration, along with printing means 90
carried within housing 88, translation means 92
for selective translatory movement of housing 88
and printing means 90 along the length of platen
36, motive means 94, and energy transmission and
distribution means 96 operably coupling motive
means 94-and printing means 90. Control assembly
100 is also provided and includes first and second
operating solenoids 102, 104, appropriate elec-
trical control circuitry 500 (see Fig. 21), and a
linkage assembly 106 operably coupled between the
solenoids 102, 104 and printing means 90 and
translation means 92.
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1 ~ Housing 88 includes a bottom wall 108,
an intermediate wall 110, ~nd a removable upper
head section 112. The walls 108, 110 are sub-
stantially rectangular in configuration, whereas
upper head section 112 presents a top wall 113
having a rectilinear forward edge 114, and an
arcuate rearward edge 116. Respective, spaced
apart sidewalls 118, 120, a rear wall 122, and a
front wall 124 extend between and interconnect the
bottom wall 108 and intermediate wall 110 to de-
fine a lower chamber in housing 88. A pair of
upper sidewall sections 126, 128 (see Fig. 9), and
an upper front wall section 125 are respectively
secured to and depend from top wall 113. A ~or-
ward bottom wall 129 is secured between sections
126, 128 to define therewith a ribbon chamber.
The sidewall sections 126, 128 are arcuate and
conform to edge 116 of top wall 113. Further,
each of these upper sidewall sections includes an
inwardly extending, yieldable, shape-retaining
flap 130, 132 which is free of connection to the
walls 110 and 113. The flaps 130, 132 extend
towards each other in an opposed relationship, and
cooperatively define therebetween a printing
2j aperture 134. The purpose of aperture 134, and
the operation of the flaps 130, 132, will be
explained in detail hereinafter.
Referring to Figs. 2 and 3, it will be
observed that the walls 122 and 124 each have a
pair of spaced apart, outwardly extending, rounded
guide nibs 136, 138 thereon. A rear guide wall
140 extends between the sidewalls 40, 42 and is
configured to present an elongated concavity 142
along the length thereof which shiftably receives
the nibs 136. In a similar fashion, an elongated,
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1 forward guide wall 144 is secured between side-
walls 40, 42 and presents a~ upstanding portion
146, a rearwardly extending portion 148, and a
rearmost, elongated, U-shaped channel 150. Up-
S standing portion 146 is provided with an elongatedconcavity 152 similar to concavity 142 which
receives the guide nibs 138.
Printing means 90 in general includes a
head assembly 154 housed within the upper portion
112 of housing 88 between intermediate wali llO
and upper wall 113, and an impacting assembly 156
disposed within the upper and lower portions of
the housing. The head assembly 154 includes an
elongated, circular, shiftable band element 158
.. 15 (see Figs. 9-14~. The band loop is in the form of
an elongated, continuous, circular strip 160 of
flexible, synthetic resin material which exhibits
plastic memory and is rotatably supported on upper
and lower bifurcated guides 161 respectively extend-
ing from top wall 113 and intermediate wall 110 (Fig.
6). The strip 160 i8 provided with a series of
spaced, juxtaposed, character-receiving openings 162
along the length thereof, as well as structure such
as secondary apertures 164 and a third series of
apertures 165 including an "extra" indexing aper-
ture 167, which serve as position indicating means
for the band element. Separate character bodies
166 are mounted in the respective openings 162 and
present opposed impact and printing faces 168,
170. The character faces 170 are three-dimensional
and are configured to present appropriate printing
characters such as the letters illustrated in Fig.
14. It will also be observed that the bodies 166
are substantially thicker than the strip 160, and
present arcuate in cross section impact faces 168.
Moreover, in preferred forms of the invention, the
bodies 166 are substantially more rigid than the
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1 strip 160, and further the character faces thereof
may be metal plated if desirjed. Finally, as best
seen in Fig. 11, the adjacent, inwardly extending
sidewalls 172 of the juxtaposed character bodies
166 cooperatively define somewhat triangular
spaces 174 between the character bodies. The
importance of these features of band element 158
will be made clear hereinafter.
Preferably, the strip 160 is formed of a
polypropylene material, whereas the bodies 166 are
formed of a fiberglass filled polycarbonate material.
In other embodiments, the band element 158 could be
formed of an appropriate metallic material, or as a
metal-synthetic resin composite.
I~ead assembly 154 further includes a
band drive gear 176 which is rotatably mounted to
an upright shaft 178 passing through the inter-
mediate wall 110. The gear 176 is provided with
teeth 180 designed to operatively mesh with the
band 158, and particularly the spaces 174 thereof
between adjacent character bodies 166. Thus,
rotation of the gear 176 through shaft 178 serves
to correspondingly rotate the band element 158.
A typin~ ribbon 182 and ribbon advance
assembly 184 also form a part of head assembly
r~ 154. In more detail, the assembly 184 includes a
continuous, arcuate guide wall 186 which depends
, from top wall 113 and is oriented to fit within
the sidewall sections 126, 128 so as to define
therebetween a narrow ribbon passageway 188. As
best seen in Figs. 8 and 9, the opposed ends of
guide wall 186 extend to points proximal to the
respective flaps 130, 132. It will also be seen
that the band element 158 is positioned in closely
spaced relationship to the inner face of guide
wall 186.
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1 . Secondary, ribbon chamber-defining walls
190, 192 are also secured ~o top wall 113 and extend
downwardly therefrom. These walls cooperate with
walls 113, 125, 126, 128 and 129 to present a ribbon
chamber 194 for holding a supply 196 of the ribbon
182 (see Fig. 2). Note in this regard that an en-
trance space 198 is provided between the wall 1~0
and section 128 for passage of ribbon from the sup~
ply 196 into and through the passageway 188, and
that an exit space 199 for the ribbon is likewise
presented between the i.nner ends of walls 190 and
192. Travel of the ribbon 182 into, along the
length of, and out of passageway 188 is facili-
litated by provision of an upstanding, ribbon-
supporting ridge 200 on wall 110 at the region
where the ribbon traverses passageway 188.
The advancing mechanism 184 also in-
cludes a spring biased cam advancer 202 disposed
within chamber 194 having an elongated arm 204
terminating in a depending operating tab 206. The
tab 206 extends through a sLot 208 provided in
walls 129 and 110 for purposes to be made clear.
The lowermost end of arm 204 as viewed in Fig. 8
is pivotally coupled to a block 210 having a slot
212 therein. A limit pin 214 connected to top
wall 113 and extending downwardly therefrom is
received within slot 212. A return spring 216 is
- operatively connected between the upper sidewall
section 126 and block 210 as illustrated. Final-
ly, the face of block 210 closest to guide wall
186 is provided with a series of ribbon-engaging
teeth 218.
Impacting assembly 156 includes a shift-
able hammer 220 having a rearmost work end 222
adapted to engage the impact-receiving faces 168
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1 of character bodies 166. The hammer 220 is dis-
posed within upper chamber!112 of housing 88 at
the same vertical level as the band element 158
(see Fig. 10).
Drive for the hammer 220 is accomplished
through an elongated, bifurcated element 224
having spaced apart legs 226, 228 joined at the
rearward end thereof by means of a crosspiece 230.
A pair of secondary hammer drive springs 232, 234
are connected between crosspiece 230 and rear wall
122 of the housing 88. A rearwardly extending,
tubular guide 236 is also secured to crosspiece
230 between the springs 232, 234. An L-shaped
guide rod 238 is secured to the underside of
hammer 220 and extends into tubular guide 236.
For this purpose, intermediate wall 110 of housing
88 is slotted as at 240 to accommodate guide rod
238 and permit back~and-forth shifting of hammer
220 as will be described. A hammer return spring
242 is operatively disposed about tubular guide
236 and is in engagement with the rearmost end of
guide rod 238 as at 244.
The impacting assembly 156 further
includes an elongated, laterally shiftable energy-
; 25 absorbing pad 246 of synthetic resin foam material
which is oriented for engagement by the upstanding
portion of guide rod 238 as hammer 220 shifts
rearwardly for printing purposes. The pad 246 is --
- supported on a ledge wall 248 extending rearwardly
from the upper margin of rear wall 122 (see Fig.
10). It will be observed that the pad 246 has an
arcuate rearmost edge 250 configured to conform to
the radius of cùrvature of roller 66, and a
slanted, forward hammer-engaging face 251.
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1 . The forward end of the element 224 is in
the form of an elongated t~ng 252. The tang 252
is pivotally coupled to a hammer cocking mechanism
254. Specifically, the mechanism 254 includes an
upright hammer gear 256 having a pair of radially
- enlarged plates 258, 260 respectively disposed
across the top and bottom margins thereof. A
radially constricted body portion 262 is connected
to an extends upwardly from plate 258, and has an
operating plate 264 connected to and extending
across the top thereof. In this fashion an annu-
lar zone 266 is defined between the plates 258,
264; the purpose of this zone 266 will be ex-
plained hereinafter.
The upper surface of operating plate 264
is provided with a pair of upstanding cam surfaces
270, 272. Each of these cam surfaces terminates
in a vertical abutment surface 274, 276 (see Figs.
16 and 19). An elongated, upright, axially rotat-
able operating shaft 278 is secured to housing
wall 108 and extends centrally through a boss 279
on wall 108 and thence through gear 256, plate
258, body portion 262 and plate 264. The shaft
and components thereon are cooperatively splined
for rotation of the gear, body portion and plates
with the shaft, while permitting selective verti-
cal movement of these components. A link 280 is
secured to the uppermost end of shaft 2-78 for
rotation therewith, but this link does not verti-
cally reciprocate with the gear 256, body portion266, and plates 258, 264. The link 280 extends
laterally from shaft 278 and is pivotally con-
nected to the forwardmost end of tang 252 as at
282.
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1A coiled spring 284 is disposed between
the underside of plates 26q and housing wall 108
about boss 279. This spring serves to bias oper-
ating plate 264 to the uppermost, hammer-cocking
position thereof illustrated in Fig. 16.
Motive means g4 is in the form of a
single, windable, coiled mainspring 286. The
mainspring 286 is disposed within a rotatable
housing 288 having a circular, peripherally flanged
bottom wall 290, an upstanding, continuous circular
sidewall 292, and an uppermost, radially outwardly
extending gear flange 294 having a series of gear
teeth 296 thereon. Housing 288 is rotatably
secured to the underside of bottom wall 108. For
this purpose, the wall 108 is provided with a
depending, stationary stud having a polygonal
section 298 and a cylindrical section 300 The
bottom wall 290 of housing 288 is provided with a
central, inwardly extending boss 302 which fits
over and rotates relati~e to the cylindrical stud
section 300. A retainer clip 304 serves to hold
housing 288 in position on the stationary stud.
The innermost end of coiled mainspring
286 is fixedly secured to a stationary block 306
- 25 connected to polygonal stud section 298 (see Fig.
5). On the other hand, the outermost end of the
spring 298 is secured to the inner face of circu-
lar sidewall 292, by means of an appropriate
retainer 308. The end of rewind cable 82 remote
from motor 80 is secured to the outer face of
circular sidewall 292 so as to allow the cable to
wind thereon during printing and spacing opera-
tions in the manner to be described.
Translation means 92 includes an elon-
gated, toothed rack 310 mounted on rearwardly ex-
tending portion 148 of guide wall 144 and extending
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1 between the casing sidewalls 40, 42. A pinion or
rack gear 312 is in operative engagement with rack
310, and with the gear téeth 296 of flange 294 (see
Fig. 20). The rack gear 312 is secured to an up-
wardly extending, rotatable shaft 314 which extendsthrough bottom wall 108 and is supported by a bush-
ing 316. The shaft 314 further extends above the
bushing structure 316 for purposes to be explained.
A second translation guide in the form of an elon-
gated, depending shaft 326 extends through bottomwall 108, is supported by bushing 318, and has a
radially enlarged guide element 320 thereon. The
element 320 rides in the U-shaped channel 150 for
guiding the translatory movement of the housing 88
during printing and spacing operations. Shaft 326
extends upwardly from bushing 318 and is journaled
in a boss, secured to wall 110.
Energy transmission and distribution
means 96 includes, in addition to the gear flange
2~4 and rack gear 312, mechanical gearing operably
connecting in parallel the printing means 90 and
the translating means 92, i.e., to rack gear 312.
In detail, the means 96 includes first and second,
peripherally toothed sun gears 322, 324 which are
maintained in meshed, driving engagement with each
other. The gear 322 is mounted for rotation on
rack gear shaft 314, whereas gear 324 is supported
on rotatable shaft 326 secured-between bott~m wall
108 and intermediate wall 110 (see Fig. 7). The
hammer gear 256 is maintained in operative, driven
engagement with the gear 322 as best seen in Figs.
4, 16 and 19; it will also be observed that gear
256 is significantly thicker than the gear 322.
The transmission and distribution means
96 further includes a pair of plane~ gears 328,
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1 ~30 respectively in meshed, driven engagement with
the corresponding sun gears~322, 324. The planet
gear 328 is secured to a rotatable shaft 332, the
latter also having a friction gear 334 thereon
above planetary gear 328. The gears 328, 334 are
maintained in planetary relationship relative to
sun gear 322 by means of a link 336 which is
somewhat L-shaped in plan configuration. It will
be noted in this respect that the link 336 in-
cludes a first, U-shaped radial portion 338 be-
tween and operatively coupling the shafts 314 and
332, with the spaced apart legs of the portion 338
rotatably supporting the gear shaft 332 and being
pivotal about shaft 314. A second radial portion
340 extends from the upper leg of portion 338
towards sidewall 12Q. This radial portion 340 is
configured to present an irregular aperture 342
therethrough having an enlarged slot-like region
! 344, as well as a somewhat smaller, arcuate region
346. The outermost end of second radial portion
340 is notched as at 348 and receives a flexible,
motion-limiting leaf spring 350. The spring 350
is secured to wall 20 as illustrated.
Planet gear 330 is likewise supported on
a rotatable shaft 352 carrying a friction gear 354
above the planet gear. A link 356 including a
first U-shaped radial portion 358 extends from and
is pivotal to shaft 326, and rotatably supports
gear shaft 352 at the outer, closed end thereof.
A second radial portion 360 extends from the upper
leg of portion 358 towards wall 118. Link 356 is
pi~otal about shaft 326, and the portion 360
thereof is slotted as at 362. Finally, the outer-
most end of portion 360 is notched as at 364, and
` 35 receives a flexible, motion-limiting leaf spring
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1 366. The latter is secured to sidewall 118 as
depicted. It will be note~ that slot 362 is of a
different configuration than the aperture 342 of
link 336.
The transmission and distribution means
96 also includes a central friction gear 368 which
is disposed between and alternately engageable by
the friction gears 334, 354. Viewing Fig. 6, it
will be observed that the central friction gear
368 is mounted for rotation on head gear shaft 178
which extends through intermediate wall 110 for
this purpose. The lowermost end of the shaft 178
is rotatably secured to bottom-wall 108 in the
known manner.
The preferred energy transmission and
distribution means in accordance with the inven-
tion includes mechanism for withdrawing only a
limited quantum or amount of energy from the
spring 286 during each printing or spacing cycle.
; 20 Such mechanism includes a peripherally toothed
; ratchet wheel 370 mounted for rotation on shaft
326 atop sun gear 324 but below the link 356. A
cooperable pawl 372 also forms a part of this
mechanism. The pawl 372 is pivotally attached to
wall 118 as at 374. A motion-limiting biasing
; leaf spring 376 of somewhat Y-shaped configuration
is also secured to wall 118 and to pawl 372 as il-
lustrated. ~hen pawl 372 is oriented in its Fi~. 20
position in engagement with a tooth on wheel 370,
rotation of the gears of assembly 96 is precluded.
- As noted above, control assembly 100
includes respective solenoids 102, 104, as well as
appropriate electrical control circuitry 500 later
to be described. The solenoids 102, 104 are
conventional and are respectively secured to
QO
, . ..
- 21 -
l bottom wall 108 by means of L-shaped mounts 378.
Each of the solenoids incl~des a reciprocable
plunger 380, 382 presenting a bifurcated connec-
tion end 384, 386.
~ 5 Linkage assembly 106 serves to operably
: couple the solenoids 102, 104 to the energy trans-
mission and distribution means 96. This assembly
106 includes an elongated linkage arm 388 secured
to connection end 386 of plunger 382. The arm 388
(see Fig. 7) includes an upstanding projection 390
closest to plunger 382, a depending nib 392 spaced
from projection 390, a pin 393 disposed within
aperture 362, and an endmost vertically offset
portion 394 adjacent and in front of the second
radial portion 360 of the link 356. The portion
394 and the main body of linkage arm 388 are
connected by an angular section 396. The e~treme
forward end of portion 394 is coupled to a trans-
versely extending link 395 (Fig. 3).
. ; 20 A linkage arm 398 similar in most re-
spects to arm 388 is pivotally secured to and
extends forwardly from connection end 384 of
plunger 380. The arm 398 includes an upstanding
. projection 400, a depending nib 402, a pin 403
disposed within slot 342, and a vertically offset
. forward.portion 404 connected to the main arm by
means of an angular section 406. However, the
forward end of portion 404 is notched as at 405.
.~ An elongated, pivotally mounted, tine-
supporting rod 408 extends transversely between
the arms 388, 398. The rod 408 is pivotally
supported beneath the linkage arms 388, 398 by
, means of respective mounts 410, 412 secured to
': wall 108. Upwardly extending arms 414, 416, are
; 35 respectively mounted on the opposed ends of rod
~ .
,.............................................. . .
., .
f` -
~7C~6~0
- 22 -
1 408 for pivoting therewith. Elongated, oppositely
laterally extending elements 418, 420 are respec-
tively secured to the uppermost ends of the cor-
responding arms 414, 416; the elements are dis-
posed rearwardly of and adjacent to the projec-
tions 390, 400~ on the linkage arms 388, 398. A
biasing spring 422 is disposed about rod 408 adja-
cent mount 412, and serves to bias the rod 408 to
the Fig. 2 position thereof. An elongated, up-
wardly extending, head gear-engaging tine 424 is
fixed to rod 408 intermediate the ends thereof and
extends upwardly between the legs 226, 228 and
through an opening 426 in wall 110 into upper
housing section 112. The upper end of tine 424 is
configured to fit between adjacent teeth 180 on
gear 176 so as to preclude rotation thereof;
shifting of tine 424 rightwardly (see Fig. 17)
permits rotation of this gear 176.
A second, elongated, transversely ex-
tending rod 428 is spaced forwardly from rod 408
and is parallel therewith. The rod 428 is sup-
ported for pivotal movement by means of spaced
mounts 430, 432 secured to wall 108. A pair of
upstanding arms 434, 436 are respectively secured
to the opposed ends of rod 428 outboard of the-
mounts 430, 432. Each arm is provided with an
outwardly extending, elongated operating element
438 or 440 which passes beneath the corresponding
linkage arm 388 or 398 just rearward of and adja-
cent to the depending nib 392 or 402 thereon. A
; link 442 is secured to element 440 and extends
~orwardly for pivotal connection to pawl 372
adjacent the tooth-engaging end thereof.
Tlle linkage arms 388, 398 are inter-
connected adjacent tlleir forward ends by means of
.
. . _
-- ~ 1i7¢~
- 23 -
1 an elongated, transversely extending rod 444. -The
rod 444 is directly couple!d to portion 404 of
linkage arm 400 just forward of notch 405. On the
other hand, the opposite end of rod 444 is pivot-
ally coupled to a connector 446. This connector446 is pivotal about a pin 448 supported on mount
450, and moreover pivots with the link 395.
A selectively operable hammer-disen-
gaging mechanism 452 also forms a part of apparatus
30. This mechanism 452 includes an elongated
shaft 454 pivotally supported by endmost mounts
456, 458 coupled to front wall 124. An upstanding
tab 460 is secured to shaft 454 adjacent notch 405
on linkage arm 398. Further, a pair of rearwardly
extending legs 462, 464 are connected to shaft 454
for pivoting therewith. The legs 462, 464 are
disposed in straddling relationship to hammer
cocking mechanism 254, and include inwardly ex-
tending operating ends 466 and 468 (see Fig. 19)
which lie within the annular zone 266 between
plates 258 and 264.
O P E R A T I O N
The mechanical operation of the above
described printing apparatus 30 will ne~t be
discussed. In order to facilitate this descrip-
tion, the various operations of character print-
ing, word spacing, tab spacing, back spacing and
carriage return will be treated separately.
; 30 Further, the discussion will assume the usual
- placement of a page 470 (see Figs. 9 and 10) about
platen 36, with housing 88 shifted to a starting
position at the lefthand end of its path of travel.
` In this orientation mainspring 286 is fully coiled
and energized. Also, at this initial rest posi-
tion prior to character printing, tine 424 is in
,
...
.. ~
r, .
i$7C~
- 24 -
1 the forward, gear-engaging position thereof, pawl
372 is in engagement with a tooth on rachet wheel
370, and the solenoids 102, 104 are deenergized
with their respective plungers 380, 382 extended.
Furthermore, the position of band element 158
relative to printing aperture 134 is known by
means of conventional position sensor 472 (Fig. 8)
forming a part of the associated electrical
control circuitry 500 and in cooperation with
secondary, position-indicating apertures 164 in
strip 160. (The sensor 472 extends through an
appropriate opening in wall 110, and is not re-
mo~ed with housing 112.) That is to say, the
particular character on band element 158 occupying
the printing position adjacent aperture 134 is always
known to ~he control circuitry 500, as through
"counting" of the apertures 164 passing the sensor
472 after resetting of the counting function in re-
sponse to passage o~ the indexing aperture 167 by a
second position sensor 473.
1. Character Printin~
Broadly speaking, character printing
operations involve depression of a desired character
key 50, whereupon band element 158 is rotated
until the corresponding selected character assumes
the printing position adjacent aperture 134.
Hammer 220 is cocked and released in timed rela-
tionship with character selection to engage and
distend the band element 158 through aperture 134
(along with the ribbon 182) for printing engage-
ment with page 470. In this character printing
operation, letterspacing is initiated simultane-
ously with commencement of band spin and hammer
cocking, and the entire cycle is timed such that
printing can occur only when proper letterspacing
or translation down rack 310 has been achieved.
,
~7~
... .
.
.,. .
~`\ f`
~17~ 0
- 25 -
1 The ratios of the gears of transmission and dis-
tribution means 96 is such'that maximum head spin
can be achieved in the time required for travers-
ing a letterspacing distance. The apparatus 3~ is
thus capable of true "on the fly" printing and
housing 88 need not actually come to a stop for
printing purposes; this is highly advantageous
when apparatus 30 is used as a machine printer.
In more detail, depression of a desired
character key 50 first causes the control circuitry
500 to determine the appropriate direction of spin
of band 158 in order to move the character body
166 corresponding with the depressed key to the
printing position, as hereinafter explained. As
noted above, band element 158 is bidirectionally
shiftable (i.e., it can be shifted either clock-
wise or counterclockwise), so that the maximum
distance of travel of band element 158 corresponds
to a 180 degree arc on the band element From a
statistical standpoint however, the average
distance of travel is much less, because of the
known frequency of occurrence of letters in aver-
age texts; further, the characters are preferably
cybernetically arranged on band 158 in a known
manner in order to minimiæe the average distance
of spin for a given printing cycle. In practice,
approximately one-half of the band is devoted to
lower case letters, numbers and punctuation,
whereas the remaining portion of the band is
devoted to upper case letters and other characters
selected through use of the shift key and de-
pression of a desired letter, number or punctua-
tion key.
For purposes of the present discussion,
it will be assumed that the shortest distance of
13L7~66D0
26 -
1 spin to achieve proper character selection at
printing aperture 134 can b,e achieved by counter-
clockwise motion. Such is assumed to have first
been determined via circuitry 500, and an energi-
zation control 9 ignal is then delivered to sole-
noid 102, causing plunger 382 thereof to rétract.
Solenoid 104 remains unenergized. This in turn
shi~ts linkage arm 388 forwardly towards wall 124.
Upon such forward shifting, projection 390 engages
element 420 and pivots tine rod 408 against the
bias of spring 422. This has the effect of
pivoting upright tine 424 leftwardly to its
release position illustrated in Fig. 17. In this
release position, the uppermost end of the tine is
pulled out of engagement with the teeth 180 of
gear 176.
Depending nib 392 next engages the
element 440 coupled to rod 428. This serves to
pivot the rod 428 with the effect that pawl 372 is
shifted via link 442 to a position out of engage-
ment with ratchet wheel 370 (Fig. 15). Also, the
interengagement of pin 3~3 and slot 362 serves to
pivot link 356 in a clockwise direction. This in
turn serves to translate planet gear 330 along the
periphery of sun gear 324 until friction gear 354
comes into operative, force-transmitting engage-
ment with central friction gear 368. Finally, the
rearward shifting of linkage arm 388 serves to
pull linkage arm 398 upwardly as viewed in Fig.
15, through the medium of link 395, connector 446,
and rod 444.
Disengagement of pawl 372 and ratchet
wheel 370 allows energy transmission and distribu-
tion means 96 to begin withdrawing energy from
spring 286 for operatiooal purposes. Sp e c if i -
~,:
( - 117C~6~)0 - ( '
- 27 -
1 cally, when the pawl 372 is withdrawn from en-
~agement with a ratchet toqth, the constant bias
of mainspring 286 serves to rotate housing 288
which in turn rotates pinion 312 to begin shifting
S of carriage housing 88 rightwardly as viewed in
Fig. 1 for letterspacing purposes. At the same
time, energy is delivered through shaft 314 to sun
gear 322, and the latter drivingly rotates sun
gear 324 and ratchet wheel 370. This serves to
rotate planet gear 330 and thereby friction gear
354. Inasmuch as the friction gear 354 has been
shifted via link 356 into engagement with central
friction gear 368, this gear likewise rotates.
Rotation of friction gear 368 operates through
shaft 178 to rotate band spin gear 176. Finally,
the gear 176 serves to spin band element 158 in a
counterclockwise direction.
Counterclockwise band spin continues
until the desired character on the band element
158 reaches the printing position adjacent aper-
ture 134. At this point the sensor 472, in
conjunction with the control circuitry 500, de-
energizes solenoid 102, whereupon plunger 382
thereof rapidly shifts rearwardly to the rest
position thereof. This has the effect of allowing
rod 408 to pivot back to its rest position under
the influence of spring 422, so that tine 424
comes back into operative, movement-blocking
position with the teeth 180 of gear 176, best seen
in Fig. 6. Tnis has the effect of stopping the
rotation of gear 176, and thus the spinning of
hand element 158.
Forward shifting of the linkage arm 388
further allows pawl 372 to be shifted back to its
` ~17~6~0 ` (~
- 28 -
1 original ratchet-engaging position through the
medium of leaf spring 376.! In this regard, the
distance between the radial teeth on ratchet 370
is proportional with the distance to be traversed
by housing 88 for a single letterspace, and the
wheel 370 is size~ such that band spin will be
completed prior to rotation of the wheel 370 past
the next adjacent radial tooth. Therefore, upon
completion of band spin, pawl 372 will engage the
l~ arcuate surface leading to the next radially
extending tooth edge. The pawl rides on this
surface until the next adjacent radial tooth
surface is reached, whereupon the ratchet 370 is
stopped, along with energy t-ransmission from
mainspring 286 through the transmission and dis-
tribution means 96. Accordingly, it will be
understood that the ratchet and pawl assembly
effectively operates to permit withdrawal of only
a limited quantum of potential energy from main-
spring 286 for a given character printing or
spacing cycle. The significance of this fact will
be made clear hereinafter.
~s noted above, initiation of head spin
; for character selection, and translation of housing
88 along rack 310, occurs substantially simultan-
eously through the transmission and distribution
means 96. Furthermore, it will be appreciated
that rotation of hammer gear 256 likewise occurs
concurrently with headspin and translatory move-
ment, inasmuch as gear 256 is coupled to pinion312 through shaft 314 and sun gear 322. During
counterclockwise rotation of hammer gear 256, two
things occur. First, it should be understood that
in the rest position of the hammer assembly, link
280 is in abutting engagement with one of the
17~ 0 (--
- 29 -
1 surfaces 274, 276 on cam plate 264. As rotation
of gear 256 proceeds, linkj280 is rotated through
- the abutment surface on plate 264 in a counter-
clockwise direction, thereby pulling tang 252 and
hammer 220 forwardly. Such movement serves to
extend and energize hammer springs 232, 234 (see
Fig. 15), and continues until the link 280 reaches
its over center position. At this point the bias
of the springs 232, 234 rapidly pulls hammer 220
rearwardly towards aperture 134 for printing
purposes. During such rearward movement, link 280
rides up and off the adjacent cam surface because
of the continued rotation of gear 256 and plate
264 until the rest position of link 280 is again
reached. Thus it will be seen that mechanism 254
serves to draw or cock the hammer during the
printing cycle, and further that the printing
; energy imparted to the hammer from the springs
232, 234 is independent of the speed of transla-
tion of housing 88. As a result, equal energy is
directed towards the page for printing purposes
- during each printing cycle.
During initial stages of hammer cocking,
tang 252 comes into engagement with tab 206 form-
~' 25 ing a part of ribbon advancing assembly-184. By
virtue of this engagement, the arm 204 is drawn
upwardly as viewed in Fig. 8 in slot 208 against
- the bias of spring 216. Furthér, the camming
action obtained via pin 214 and slot 212 causes
the teeth 218 on block 210 to engage the ribbon
182 and pull the same in a clockwise direction
around arcuate ribbon passageway 188. After the
ribbon has been incrementally shifted in this
, manner, spring 216 serves to return block 210, and
thus arm 204, back to the rest position illus-
.. . .
: , - - ,
~!
,, .
.~
., :
:, `
i~; ~ - .
117~0
- io -
1 trated in bold lines in Fig. 8. Such return to
the rest position occurs p'rior to complete cocking
and rearward travel o~ hammer 220.
From the foregoing description it will
be appreciated that overall printing means ~0 is
characterized by the property of having different
total motive energy requirements for operation
thereof during different printing cycles. That is
to say, the energy required for hammer cocking
(and consequently adYance of ribbon 182) is con-
stant for each printing cycle, whereas the amount
of energy required for character selection varies
and depends upon the distance the band element
must be rotated in any given instance.
The above consideration becomes impor-
tant when it is realized that the limited incre-
ments of energy withdrawn from mainspring 286 for
each printing cycle via the energy transmission
and distribution means 96 and ratchet 370 and pawl
372 are always greater than the amount of energy
needed to operate the printing means for band
element spin and hammer cocking. An important
feature of the present invention is that excess
energy over and above that required for operation
of the printing means per se is directly and
instantaneously transferred to increase the speed
of translation of the housing 88. Referring to
Fig. 20, it will be seen that after the total
energy requirement for the printing means 90 is
determined (by the amount of headspin needed for
- character selection), substantially all of the
remaining energy from the amount or quantum with-
drawn is directed through pinion 312 for housing
advancement (the sun gears 322, 324, planet gears
328, 352 and l~ammer gear 256 also rotate sub-
.
L7¢~,~0~
- 31 -
l sequent to cessation of headspin; nevertheless,
these gears, with the possible exception of hammer
- gear 256, are not involved in energy transmission
in this mode of operation).
The upshot of this operational charac-
teristic is that carriage speed along ratchet 310
is variable between different printing cycles.
Thus, if only minimal band element ~pin is re-
quired for character selection, speed of trans-
lation is increased. Conversely, if more sub-
stantial quantities of energy are consumed in band
spin, the speed of translation is decreased.
Further, it will be appreciated that energization
of hammer 220 is independent of the speed of
translation and/or any variations therein, so that
printing-characteristics are maintained constant
regardless of translation speed.
Actual printing on page 470 occurs as
follows. First, it will be understood that the
respective gears making up energy transmission and
distribution means 96 are sized such that the
travel of hammer 220 towards page 470, and sub-
sequent printing thereon, can occur only at the
instant proper letterspacing has been achieved by
translation of housing 88, or shortly thereafter.
Thus, the possibility of overprinting between
adjacent characters is eliminated. As hammer 220
is propelled rearwardly under the action of ener-
gized springs 232, 234 and guided by the inter-
fitting of guide 236 and rod 238, it first engages
the selected character body 166 positioned at the
region of printing aperture 134. Inasmuch as the
work end 222 of hammer 220, and the impact-receiv-
ing face 168 of the character body 166 are com-
plementally configured, the work end tends to home
~i7~6Qo ` ~)
- 32
1 in and center itself relative to the character
body. Further rearward trjavel of hammer 220
s~rves t~ distend the flexible band ele~ent 158
outwardly through opening 134. ~eferring to Fig.
9, it will be seen that such distension of the
band element 158 serves to engage and rearwardly
distend or shift the flaps 130, 132. Further, by
virtue of the relatively rigid nature of the
character bodies 166 as opposed to tke strip 160,
considerable flexure occurs on opposite sides of
the the character body being printed. Hence, the
body being printed is pressed towards page 470
while the adjacent juxtaposed character bodies are
bent forwardly at a significant angle relative to
the body being printed. In this way the possi-
bility of smearing or overprinting because of
close spacing between the character bodies is
eliminated. Again referring to Fig. 9, it will be
seen that the ribbon 182 is distended outwardly
with the band element 158 during the printing
process. Thus the character face 170 of the
selected body 166 is imprinted on page 470 through
the medium of ribbon 182. During actual printing,
hammer 220 contacts pad 246 and particularly face
251 thereof and thus an amount of impact energy is
; absorbed; in order to vary and limit the actual
amount of impact energy delivered to page 470, pad
246 may be shifted laterally to increase or de-
crease the effective depth thereof at the printing
position.
~ After the actual printing operation is
completed, hammer 220 is returned to its original
rest position under the influence of return spring
242 (Fig. 10). It will be understood in this
re~ard that as hammer 220 was propelled rearwardly
(` ` (':
li7~0
- 33 -
1 under the influence of springs 232, 234, return
spring 242 was extended an~ energized. Thus, the
ha~ner 220 is retracted forwardly by the spring
242 after character printing is completed. The
5 band element 152 also returns to its original rest
; configuration after hammer 220 retracts. This
occurs in part because of the shape-retaining
nature of the synthetic resin strip 160, and more
significantly because of the resilience of the
flaps 130, 132 which tend to push the band for-
wardly to the original position thereof.
The foregoing discussion assumed that
the position of the character to be printed vis-a-
vis printing aperture 134 dictated counterclock-
wise rotation of band element 158. In the eventthat clockwise rotation of band element 158 is
called for (such being determined by sensor 472
and the control circuitry 500), the following
operation ensues. First, an energization control
signal is directed to solenoid 104 in order to
retract plunger 380 thereof, while solenoid 102
remains unenergized. Thus, linkage arm 398 is
shifted rearwardly to accomplish the exact same
functions hereinabove described when solenoid 102
is energized and linkage arm 388 shifted rear-
wardly. That is to say, rearward shifting of the
linkage arm 398 serves to move tine 424 to the
band-releasing position thereof of Fig. 17; to
shift pawl 372 away from engagement with ratchet
3~ wheel 370 in order to begin withdrawal of a quan-
tum of energy from mainspring 286 and correspond-
ing rotation of flange gear 294, pinion 312, sun
gears 322, 324, planet gears 328, 330 and hammer
gear 256; tQ translate planet gear 332 such that
friction gear 334 engages central friction gear
117 as 0 0
- 34 -
1 368 to thereby commence clockwise rotation of gear
176 and band element 158. I Referring to Fig. 2, it
will be observed that pin 403 normally is disposed
within restricted arcuate region 346 of aperture
342, so that upon essentially rectilinear rearward
shifting of the linkage arm 398, link 33~ operates
in the manner heretofore described with respect to
link 356.
When character selection is completed,
solenoid 104 is deenergized, and linkage arm 398
shifted rearwardly. This shifts tine 424 to its
band-stopping position; and allows pawl 372 to re-
engage wheel 370 and stop operation of energy
transmission and distribution means 96 when the
pawl engages the next ratchet tooth.
In short, it will be seen that counter-
clockwise shifting of band element 152 is ac-
complished by energiæation of solenoid 102, where-
as clockwise rotation is effected by energizing
solenoid lQ4. In both cases the mechanical opera-
tion is essentially the same, save for the dif-
ference in band spin direction. Accordingly, no
further discussion of clockwise band spin printing
is believed necessary.
The fact that band 158 and related
structure is spaced ~at least about 1/8 inch) from
- page 470 ensures that the line of write will be
visible at all times during printing. This is
necessary for using apparatus 30 as a conventional
typewriter.
; -~. The mechanical letterprinting operation
- of apparatus 3Q is identical to that described
- above if the apparatus is used as a machine prin-
ter. In this mode of operation, remote input from
a computer or phone coupling or the like replaces
:.
117(:~6~0
- 35 -
1 depression of letter keys 50, but in all mechan-
ical respects the operation of apparatus 30 re-
mains unchan~ed.
It will also be understood that after a
given character printing operation is completed,
the apparatus 30 is ready for the next character
printing or spacing operation without additional
mechanical operations. Specifically, tine 424 is
in its movement-blocking position relative to band
spin gear 176, the solenoids 102, 104 are ready
for energization as appropriate, and the orienta-
tion of band element 158 vis-a-vis printing aper-
ture 134 is sensed and determined. Therefore,
additional character printing or spacing opera-
tions can proceed smoothly and essentially instan-
taneously.
2. ~Jord S~acing
After a given word is typed on page 470,
the operator will normally depress spacing bar 52
in order to translate housing 88 along rack 310 a
letterspace distance.
When the bar 52 is depressed, energiza-
tion control signals are sent to both of the
solenoids 102, 104, in order to energize the same.
This has the effect of rearwardly shifting the
respective linkage arms 388, 398 (Fig. 18).
Simultaneous shifting of these linkage arms ac-
complishes many of the functions of character
; 30 printing described above, but also brings hammer
disengaging mechanism 452 into play so that no
printing occurs on page 470. Further, the energy
from spring 286 normally devoted to hammer cocking
and ribbon advance is directed to increasing the
translation speed of housing 88; thus, word
spacing is extremely fast.
~a7c~0 - ¢~
- 36 -
1 Specifically, rearward shifting of the
linkage arms 388, 398 firsjt rotates tine rod 408
via the projections 390, 400 and the associated ~-
elements 418, 420, so that tine 424 is shifted to ~,
its Fig. 17 release position. Pawl 372 is also ~j
withdrawn from engagement with ratchet wheel 370
by virtue of rotation of rod 428 through the
medium nibs 392, 402 and the adjacent operating
elements 438, 440.
The link 356 operatively coupled to the
linkage arm 388 is pivoted in response to rearward
movement of the linkage arm in the manner described
above, in order to translate planet gear 330 and
cause friction gear 354 to come into force-trans-
mitting engagement with central friction gear 368.
This in turn rotates shaft 178, gear 176 and band
element 158. Finally, linkage arm 398 is pulled
towards linkage arm 388 through link 395, con-
nector 446, and rod 444. This serves to pull the
rod 398 such that notch 405 thereof receives tab
460. Pulling of the linkage arm 398 towards arm
; 388 further serves to shift pin 403 into slot-like
region 344 of aperture 342. In this orientation
; it will be observed (Fig. 18) that the pin 403 is
ineffective to pivot the link 336. Thus planet
gear 328 remains in its rest position and does not
interfere with the rotation of central friction
gear 368.
Although rearward shifting of link 398
does not, by virtue of the configuration of aper-
ture 342, pivot the link 336 (when both solenoids
100, 102 are energized), it does initiate opera-
tion of the hammer disengaging-mechanism 452.
Specifically, referring to Figs. 18-19, it will be
seen that the notched portion 404 of linkage arm
- f ~17~65~0 ~
- 37 -
l 3~8 engages the tab 460 with the effect that shaft
454 is pivoted axially. ~Jhen this occurs, the
respective legs 462, 464 are likewise pivoted in a
downward direction. The operating ends 466, 468
of these legs thereby engage the upper surface of
plate 258, with the effect that the gear 256,
plate 258, body portion 262 and plate 264 are all
shifted downwardly against the bias of coil spring
284. In this lowered, disengaged position (Fig.
19), the abutment surfaces 274, 276 on plate 264
are disposed beneath link 280. Therefore, the
gear 256, plate 258, body portion 262, and plate
264 rotate beneath link 280 but do not engage the
latter. Accordingly, when the ~echanism 452 is in
operation, no shifting or cocking of the hammer
220 occurs-.- Note in this respect-that the width
of gear 256 is greater than that of the associated
sun gear 322; therefore the gear 256 can be
shifted vertically relative to sun gear 322 with-
out affecting the engagement between these ~ears.
In order to cease the spacing operation,
the solenoids 102, 104 are deenergized in timed
relationship with translation of housing 88. De-
energization effects forward shifting of the
linkage arms 388, 398, and brings the entire
mechanism back to its rest position for another
printing cycle. Specifically, forward shifting of
the arm 398 permits counterrotation of the legs
462, 464 and shaft 454 (such being caused by the
~ 30 bias of spring 284) so that the hammer cocking
,~ mechanism 254 returns to its Fig. 16 position. In
addition, the linkage arm 398 is shifted laterally
such that pin 403 returns to the restricted ar-
cuate region 346 of aperture 342. ~lso, forward
shifting of the linkage arms effects movement of
;`
:
, .
,.
.
i: .
,.,
.,
:: .
-~ 117~6~0
- 38 -
1 planet gear 330 back to its Fig. 2 position through
the medium of pin 393 and llink 356.
3. Tab SpacinR
Tab spacing is accomplished from a mechani-
cal standpoint in exactly the same manner as the
word spacing operation heretofore described. That
is to say, in order to initiate tab spacing for a
given distance along page 470, energization con-
trol signals are sent to solenoids 102, 104 for
simultaneous operation thereof. I~Jhen the appro-
priate distance has been spaced, the respective
solenoids 102, 104 are deenergized.
During the period of energization of the
solenoids, the mechanical functions described
above with respect to word spacing obtain. Thus,
tine 424 is in the release position thereof; pawl
372 is withdrawn from engagement with ratchet
wheel 37Q; planet gear 330 is pivoted relative to
sun gear 324 such that friction gear 354 engages
central friction gear 368 for rotation thereof,
and as a result gear l76 is rotated along with
; band element 158; and hammer disengaging mechanism
452 operates to disengage the hammer mechanism
~5 from transmission and distribution means 96, in
order to prevent any movement of hammer 220.
It will be appreciated from the fore-
going description that during tab spacing opera-
tions housing 88 is shifted under the constant
bias of mainspring 286. Inasmuch as no ener~y is
wasted in movement of hammer 220, a substantial
portion of the energy withdrawn from mainspring
2~6 is transmitted directly to pinion 312 for
increasing the speed of translation. However, it
will also be apprecia~ted that the speed of trans-
-- .. _. __ . _ ......... ... . .
.
7~600 ` f';
- 39 -
1 lat-ion attained by housing 88 could be sufficient
to actually damage or destjroy the printing mecha-
nism at the end of the tab spacing cycle. Ac-
cordingly, it is very desirable to govern the
speed of translation during tab spacing. This is
accomplished in the present invention by causing
rotation of gear 176 and band 15~ during tab
spacing, as noted above. In effect, the gear and
band element cooperatively present a rotatable
airfoil element which limits the top speed attain-
able b~ housing 88 during tab spacing. As noted,
without such a governing feature, potentially
destructive speeds of translation are a possi-
bility.
At the end of the tab spacing cycle, the
solenoids 102, 104 are deenergized at the proper
instant in order that pawl 372 comes into engage-
ment with the arcuate surface of ratchet wheel 370
just ahead of the ratchet tooth corresponding to
the end of the desired tab spacing. When the pawl
372 engages this tooth, energy ceases to be with-
drawn from mainspring 286, the gear trains de-
fining the transmission and distribution means 96
are stopped, and translation down rack 310 ceases.-
The solenoids 102, 104 are in mechanical
parallel during word or tab spacing and coopera-
tively define a mechanical control gate for such
spacing. Thus, when one or the other of the
solenoids is energized, the mechanical spacing
gate is closed and printing occurs, but when both
solenoids are energized, the spacing "gate" is
opened and spacing can obtain.
~ . .
7(:~6Qo (~
- 40 -
1 - 4. Backspacin~
If it is desired Ito backspace one or more
letterspacing distances, key 62 is correspondingly
depressed. This has the effect of energizing
S motor 80 through the control circuitry 500 in
order to draw housing 88 leftwardly as viewed in
Fig. 1. Incremental backspacing in this fashion
occurs a letterspace at a time, in the usual
manner. It will be appreciated that during such
backspacing output spool 84 of motor 80 rotates in
a clockwise direction in order to draw housing 88
leftwardly through the medium of cable 82. During
backspacing however, no mechanical operations
within housing 88 are underway, save for incre-
mental rotation of housing 288 under the influence
of cable 82; this of course has the effect of in-
crementally energizing the mainspring 286.
5. Carria~e Return
When housing 88 reaches the end of a line
of write on page 470, it is necessary to return
the housing to its leftmost position for commenc-
ing another line of write. Depression of carriage
return key 64 effects this shifting by causing
energization of motor 80 and consequent clockwise
rotation of spool 84. This has the effect of
winding up cable 82 onto spool 84, and corres-
ponding unwinding the cable from mainspring hous-
ing 288. This in turn serves to energize spring
286 so that the same has sufficient potential
energy for accomplishing all line of write func-
tions as the housing 88 again traverses page 470
going from left to right.
In view of the foregoing, it will be
appreciated that motor 80 is activated only during
.
7~6(~0
~ ,
- 41 -
1 backspacing and carriage return operations; it
does not contribute any motive energy during
character printing, word spacing or tab spacing.
Those skilled in the art will thus appreciate that
if it is desired to construct a wholly manual
machine, means can be provided for manual carriage
return with consequent energization of spring 286.
It will also be readily understood that conven-
tional, mechanical, paper advance or line feed
1~ mechanism and/or other known typewriter features
and options can be mechanically or electrically
incorporated into the apparatus of the present
invention without departing from the principles
thereof.
As in the case of printing, the func-
tions of word spacing, tab spacing, backspacing
and carriage return can all be controlled by
signals from a computer or the like rather than
from the keyboard 34. This alternative will be
described in detail hereinafter.
After ribbon 182 is consumed during
printing operations, the entire housing 112 is
simply removed an~ discarded, and a replacement
housing installed. Inasmuch as the housing 112
contains band 158 and ribbon advance mechanism
184, these components will likewise be replaced
with the new ribbon. The simple, low cost nature
of the band and related structure makes this a
practical possibility. This feature also makes
changeovers to different styles of type a simple
matter, inasmuch as a replacement head assembly
having a band element with different style charac-
; ters thereon can be employed.
.
; .
- 42 -
l E L E C T R I C A L C 0 N T R 0 L
~ s those skilled in the art will appreciate,
the general manner of accomplishing the control func-
tions required for operation of the previously de-
scribed, essentially mechanical apparatus consti-
tuting the thrust of this invention may utilize a
variety of approaches relying in varying degrees upon
mechanical, electromechanical and electronic tech-
10- niques of largely or entirely conventional type. lt
will be further perceived that the particular manner
of implementing various individual control functions,
as well as whether or not certain optional functions
are to be implemented at all, will depend in large
measure upon the intended application for the pre-
vious ly described apparatus of this invention and
the design preferences of the implementer. Accord-
ingly, the purpose of Fig. 21 should be understood
as primarily for illustrating exemplary approaches
to the implementation of what might be regarded as
a typical, basic set of control functions for the
printing apparatus 30.
In the control circuitry 500 depicted in
Fig. 21, components previously mentioned in the
foregoing description of the apparatus 30 may be
identified at the outset as including the solenoids
102 and 104 and the motor ~0, which are the primary
components over which functional control is to be
exercised consistently with their operation as
previously described. The embodiment depicted in
Fig. 21 also includes a third solenoid 502, which
is preferably provided in implementations of the
apparatus 30 intended for primary or alternate con- I
- trol from a computer, which will be understood is
adapted upon actuation for operatin~ a ratchet or
.. . I
-
,
., .
,
7 ~ 6~ 0
- 43 -
1 other conventional mechanism (not shown) operably
coupled with the platen 36 for incrementally rotating
th~ latter to accomplish vertical paper advancement
or line feed without the necessity of concurrently
returning the carriage assembly 78 to the left margin
as is normally inherent in typical carriage return
controls. It should be understood, however, that the
line feed solenoid 502 is optional and that paper
advancement may be implemented with conventional,
mechanical means which operate in response to the
carriage-return control, particularly in lower cost
implementations of the apparatus 30 intended for
use primarily as a typewriter.
It may also be helpful to next note the
identity and general nature of the component assem-
blies from which control over the functioning of the
motor 80, the solenoids 102 and 104 and the solenoid
502, if provided, will be exercised in a typical
arrangement. Such control exercising aspect of
the apparatus 30 will normally, although not manda-
torily (as in a prlnt only embodiment of the apparatus
30), include a keyboard 34 as previously described,
which typically will have a plurality of character
selection keys 50 (of which only one is shown in
Fig. 21), a spacing bar key 52, a tab spacing key 60,
a backspacing key 62, a carriage return key 64~ a
line feed key 65, and other control keys such as a
shift key 54. The keyboard 34 can be constructed in
various fashions in which each of the mentioned keys,
for example, actuates an electrical switch, controls
an electro-optically implemented matrix or the like.
The keyboard 34 will also, however, typically include
logic circuitry 504 of conventional type for accomp-
lishing an electrical encoding of the actuation of any
particular one of the mentioned keys into an electri-
,,
.,
c
!`
~,
6QO ~'
- 44 -
1 cal signal, which is unique to the actuation of that
particular key, is represent,ed by the binary bit
values of a composite electrical signal having several
bit "positions" (typically 7 or 8), and is output
from the key encoding logic 504 upon an appropriate
keyboard output line 506. Although the encoder 504
could be arranged to output the key representing sig-
nals in the form of a sequence of bit values in time
sequenced or "serial" form, which would then typical-
ly be further encoded at an appropriate stage of thefunctional control into a plurality of bit values
simultaneously available as concurrent electrical
signals upon separate output lines in "parallel"
form, current practice would favor encoding of the
key signals into such simultaneous bit value,
parallel for within the keyboard encoder 504 itself,
and it will be assumed for purposes of further ex-
planation that the keyboard output line 506 contains
a plurality of conductors concurrently carrying,
say, 7 bit values representing a conventional or other
electrical encoding which is unique for each charac-
ter and control function to be handled. One popular
method of parallel encoding employing 7 bit values,
which thereby provides 128 unique codes including
an all "zero" null code and an all "one" null or
"deleted" code, devotes 31 of the codes having the
smallest binary number equivalent to control func-
tions such as line feed, carriage return, back-
spacing, tabbing, etc., while the remaining 95 codes
are used to represent a space and each of 94 print-
able characters respectively. For purposes of fur-
ther explanation, such a code will be assumed for
illustrative purposes.
Where the appara~us 30 is to be coupled
with and subject to control from outside signal
_ _~'t :; :.. . . .
1~L7~Ç~o ` f
1. sources, as well as from the Iceyboard 34, the elec-
trical signals for that purp,ose will normally come
from either the interfacing circuitry within a com-
puter or from a communications line associated with
a computer, as broadly indicated by the block 508
in Fig. 21. When such signals are passed directly
between computer interfacing circuitry and the
apparatus 30, such is normally done by means of a
multi-conductor line 510 similar to the line 506
coupled with the output of the keyboard 34, and will
be in the same parallel encoded form. The repre-
sentation contemplated by the block 508 also includes,
however, arrangements in which a telephone or other
communications line may be intermediately utilized
with the transmission of data thereover in serial
form decoded and encoded at the opposite extremities
of the communications.line by so-called "modems", in
which case it will be preferable that the block 508
be understood as including suitable encoding circuitry
at some point adjacent the apparatus 30, so that com-
munication with the rest of the apparatus 30 over
line 510 can be assumed to be in the same parallel
encoded form already assumed ~or the output of the
keyboard 34 via the line 506.
Where both a keyboard 34 and a computer or
remote data source 508 are to be utilized in a given
system, the control circuitry 500 will preferably
also include mode control logic circuitry 512 per-
mitting selection of a desired operating mode in
response to encoded commands received from either
~ the keyboard 34 or the alternate data source 508
: via the lines 506 and 510 respectively. Various
operating modes may be provided for depending upon
the nature of the desired application, including
normal control over the printing apparatus 30 by
I :
.
,~ i
.
.,.
7(~6(~0
- 46 -
1 the keyboard 34 but with output from the com~uter or
other source 508 able to override the keyboard 34 and
ass~e control over the printing apparatus 30 when-
ever information for printing becomes available from
S the source 508, or vice versa, as well as sub-modes
in which the encoded output from the keyboard 34 is
delivered only to the remainder of the control cir-
cuitry 500 or in which output from the keyboard 34 is
either exclusively or also delivered to the computer
or the like 508 via the line 510 (which is preferably
bidirectional).
Regardless of whether encoded data to be
printed is being accepted from the keyboard 34 or the
alternate source 508, dependent upon the selected
mode in which the mode control logic 512 is operating,
the latter will deliver the multi-bit, encoded,
parallel bit signal as an output upon a multi-
conductor line 514, which is in turn coupled as the
input to decoding logic circuitry 516. The decoding
logic circuitry 516, ~7hich may be conventional incharacter (as is also true of the other componentry
of the control circuitry 500), serves to separate
out encoded signals representing valid codes for the
various printable characters and to deliver those
signals to the output line 518 in their parallel en-
coded form, to recognize an encoded signal validly
representing a space and to produce in response there-
to a direct current logic signal delivered to the
: single output line 520, to recognize encoded signals
respectively representing carriage return, tabbing,
line feed and backspacing commands and to produce
in response thereto respective direct current logic
signals delivered to the single output lines 522, 524,
526 and 528 respectively, to recognize and suppress
; 35 fror delivery to the re~ainder of the control circuitry
1~ 7~i00
- 47 -
1 500 encoded signals representing commands or control
functions not implemented injthe particular system
provided, and to generate and deliver to a single
output line 530 an enabling logic signal repre-
senting the presence in the decode logic circuitry516 of a new encoded parallel signal corresponding to
a printable character ready to be processed (which
enabling signal can conveniently be derived from
ORing of the bit values from certain bit positions
of the fully encoded multi-bit signal).
Before tracing the manner in which the
control circuitry 500 may respond to the various ones
of the mentioned output signals from the decode logic
circuitry 516 to operate the motor 80, solenoids L02
and 104 and solenoid 502, if tne latter is provided,
it may be helpful to identify certain of the more
mundane electrical and electronic components and
circuitry which will preferably be conventionally
associated with the controlled components 80, 102,
104 and 502. The terminals 532 and 534 represent
connections to an AC power source line. The termi-
nals 532 and 534 are respectively connected with
the alternating current power leads 536 and 53~, and
the latter is in turn connected with one terminal of
the motor 80. In order to provide for quick-acting
energization and deenergization of the alternating
current motor 80 in response to a typically low
voltage, direct current, logic signal, some suit-
able form of electronic switching component 540,
such as a Triac, is employed. The electronic switch-
ing component 540 has a control terminal 542 to which
the mentioned type of logic signal may be selective-
ly applied for controlling the operation of what is
tantamount to a normally open switch 544 interposed
between the alternating current power lead S36 and
117~6C~0
- 48 -
1 an extension 546 of the latter connected wi.th the
other terminal of the motor ,80. When an appropriate,
direct current, control signal is delivered to the
terminal 542, the switch 544 is immediately closed
to energize the motor 80 for operation, it being
noted that a 40-watt, single phase, alternating
motor having a capacitor start will suffice for the
motor component 80 in typical implementations of
the apparatus 30 and is found to provide the desired
quick starting response upon "closure" of the Triac
switch 544, as well as quick stopping of the motor
component 80 when the Triac switch 544 is "reopened"
upon withdrawal of the logic control signal from the
terminal 542 of the switching device 540.
The alternating current power leads 536
and 538 are also respectively coupled by leads 548
and 550 with a preferably regulated, rectifying,
power supply 552 for providing from its output leads
554 and 556 a source of relatively low (say, 5 volts),
direct current operating power for the various,
electronically implemented, logic components and
associated circuitry included in the control circuit
500. For the sake of clarity in the drawing, the
individual connections of such logic operating sup-
ply voltage to the various logic components are notindividually shown, but the manner of connection
thereof is conventional and will be apparent to those
`~ skilled in the art.
Respective extensions 558 and 560 of the
AC power leads 548 and 550 energize a relatively
,~ low voltage (say, 24 volts), rectifying power sup-
. ply 562 for providing operating power for the solenoids
102, 104 and 502 upon its output leads 564 and 566.
The solenoids 102 and 104 are preferably of the quick-
actin~ type having relatively low impedence windings
,
~ .
~7(~
- 49 -
1 such as, say, 32 ohms, while the solenoid 502 may be
of a somewhat heavier duty type to provide the mechani-
cal force required for ratcheting the platen 36.
Preferably, each of the solenoids 102, 104 and 502
will be provided with conventional switching and
driver circuitry as at 568, 570 and 572. Each of
the drivers 568, 570 and 572 desirably may include a
resistance-capacitance network as at 574, 576 and
578 respectively, coupled in shunt across the winding
of the corresponding solenoid 102, 104 or 502 for
the purpose of quickly "dumping" the solenoid winding
circuit upon deenergization thereof, so that the
involved solenoid 102, 104 or 502 will then be
rapidly restared to its unactuated, standby condi-
tion. Each of the drivers 568, 570 and 572 also in-
cludes a transistorized or otherwise conventionally
implemented electronic switch as at 580, 582, and
584 respectively, which are in turn controlled by
control input terminals 586, 588 and 590 respec-
tively. It will be understood that the electronicswitches 580, 582 and 584 are normally "open", but
are adapted to be immediately "closed" upon applica-
tion of a direct current, logic, control signal to
the corresponding control terminal 586, 588 or 590
and to immediately "reopen" upon the withdrawal of
such control signal. As will be apparent from Fig.
21, the direct current power lead 564 is coupled by
leads 592, 594 and 596 with one end of the winding
of each of the solenoids 102, 104 and 502 respec-
tively, while the power lead 566 is coupled via theleads 59~, 600 and 602 respectively and the driver ~
switches 580, 582 and 584 with the other end of the
windings of the solenoids 102, 104 and 502. Thus,
acutation and deactuation of each of the solenoids
102, 104 and 502 respectively is directly responsive
7(~ 0
- 50 -
1 to the application or withdrawal of a suitable direct
current, logic, control signal at the corresponding
driver switch control terminal 586, 588 or 590 re-
spectively.
The basic operation of the mechanical com-
ponents of the printing apparatus 30 to perform various
functions in response to energization and deenergi-
zation of the motor 80 and the solenoids 102 and 104
have previously been described in general terms.
It is believed, however, that understanding of
certain more detailed aspects of the operation of
- the control circuitry 500 being described for
illustrative purposes will be facilitated by
considering the same in a somewhat different order
than chosen for description of the mechanical
operations above, and specifically by reserving
discussion of the character printing function
until the operation of the control circuitry 500
has been considered for certain of the less com-
plex functions.
Accordingly, with respect to the back-
spacing function, it will be recalled that such
function is actuated by the appearance upon the
lead 528 of a logic control signal from the decode
logic circuitry 516. Such signal is initially fed
to a multivibrator 604, which responds by de-
livering to its output lead 606 a logic signal
coupled to the control terminal 542 of the Triac
electric switching device 540 for the motor 80.
When such logic signal is present on the line 606,
the switch 544 is "closed" and the motor 80 is
energized during the duration of application o~
such logic signal to the terminal 542. The multi-
vibrator 606 may be of the "one-shot" type adapted
to delivcr the mentioned control signal to the
-` ( 117~6~30
- 51
1line 606 for a duration of about 50-100 milli-
seconds, during which the mo;tor 80 will be briefly
operated for a period suitable for backspacing the
carriage assembly 78 by one character space. If
S .desired, the multivibrator 604 may be implemented
as of the "free-running" type, with a second
"half-cycle" period equal to some suitably longer
fraction of a second, in which case continued
backspacing of the carriage assembly 78 may be
effected by the operator of the keyboard 34 by
retaining the backspace key 62 depressed until the
desired backspacing distance has been covered.
We may next consider the optionally pro-
vided, separate line feed function, which is
actuated by the delivery of a suitable logic sig-
nal to its output line 526 by the decode logic
circuitry 516. The logic signal upon line 526
triggers a multivibrator 608 to deliver to its
output line 610, and thereby to the control termi-
nal 590 of the driver 572 associated with the linefeed solenoid 502, a logic signal of suitable
duration for causing the latter to ratchet or
otherwise advance the platen 36 by one line in a
vertical direction. The multivibrator 608 may be
25 of the one-shot type, and a suitable period of the
output signal delivered to the line 61U for paper
advancement equal to one vertical line will typi-
cally be of the order of about one hundred milli-
.seconds. If desired, the multivibrator 608 may be
implemented as of the free-running type, with a
second half-cycle duration of some suitably longer
fraction of a second, whereupon continued depres-
sion of the line feed key 65 by the operator of
the keyboard 34 will result in iterated line feed
operations until the paper has been advanced the
`6~0
- 52 -
1 desired number of vertical lines.
An important auxiliary aspect of the
line feed and several of the other functions is,
as previously noted, the desirability of energi-
- 5 zing the main solenoids 102 and 104 during periods
of relative movement between the carriage assembly
78 and the paper carried by the platen 36, in
order to positively disable the character printing
mechanism during any such intervals. This is
accomplished for the line feed function in the
illustrative embodiment of Fig. 21 by coupling the
line 610 through a diode or other isolating com-
ponent 612 to a lead 614, which is in turn coupled
both with a lead 616 connected to the driver
switch control terminal 586 for the solenoid 102
and via a delay component 618 with a line 620
connected with the driver switch control terminal
588 for the solenoid 104. It is desirable for the
mentioned purpose that the solenoid 102 be ener-
gized slightly prior to the energization of thesolenoid 104, so that the delay component 618,
which may be implemented in any conventional
fashion, will provide a brief delay of the order
of five milliseconds for energization of the
solenoid 104 following energization of the sole-
noid 102. Such energization of the solenoids 102
~ and 104 is, of course, discontinued immediately
- upon the termination of the first half-cycle logic
signal delivered by the multivibrator 608 to the
line 610 and thereby to the driver control switch
terminal 590 which controls operation of the line
feed solenoid 502.
The spacing function may next be con-
sidered, and will be observed to be responsive to
the presentation of a logic control signal by the
` 117~6QCI
1 decode logic circuitry 516 upon its output line
520. The signal upon line 520 is delivered to a
m~ltivibrator 622 having a first half-cycle period
of the order of thirty milliseconds during which
it delivers a logic signal to the previously
mentioned line 614, which results in energization
of the solenoid 102, followed by slightly delayed
energization of the solenoid 104, and continuance
of the energization of both of those solenoids
during a period suitable for permitting the car-
riage assembly 78 to advance horizontally one
character space to the right (say, about ten milli-
seconds). If the multivibrator 622 is of the one-
shot type, only a single space advancement will
occur; but, if the multivibrator 622 is imple-
mented as of the free-running type with a second
half-cycle period of some appropriately longer
fraction of a second, then the operator of the
keyboard 34 may effect iterated spacing operations
by continued depression of the spacebar key 52.
Directing attention next to the tabbing
function, which is activated by the presentation
by the decoding logic circuitry 516 of a logic
control signal upon its output line 524, it should
first be mentioned that the tab sensing means 624
may be implemented in a variety of conventional
fashions including optical-photoelectric sensing,
direct electrical switching or, as preferred for
convenience, the employment of tab position indi-
cating magnets adjustably positionable along the
: width of the structure supporting the platen 36,
with a Hall effect sensor then carried by the car-
riage assembly 78 for detecting whenever the lat-
ter horizontally moves into a position of align-
ment with any particular tab position, it being
~ .
.
6 Q O f
- 54 -
1 understood that the tab sensing means 624 will
deliver an appropriate logic:signal to its output
line 626 whenever the carriage assembly 78 is
positioned at or reaches a selected tab position.
The initial logic signal upon line 524 is prefer-
ably delivered to a one-shot multivibrator 628
adapted to in turn deliver to its output line 630
a first half-cycle logic signal of relatively
short duration sufficient merely to permit the
carriage assembly 78 to advance away from any tab
location upon which it may be setting at the time
the tabbing function is invoked (a first half-
cycle period of about ten milliseconds or a little
more typically being sufficient for this purpose).
Since the tabbing function may be desired to be
invoked while the carriage assembly 78 is posi-
tioned at some selected tab location, with the
sensing means 624 thus delivering a logic signal
to its output line 26, it is necessary to provide
for getting the tabbing movement of the carriage
assembly 78 started even under that circumstance.
This may be done by suitable logic circuitry such
as an OR gate 632 having an invert input for the
signal from line 626 and a non-invert input for
the signal from line 630. The gate 632 delivers
an appropriate logic signal through its output
lead 634 to the previously mentioned lead 614
whenever the multivibrator 628 is delivering its
logic signal to the line 630 or whenever the tab
sensing means 624 is not delivering its logic
signal representing positioning of the carriage
assembly 78 at a selected tab location to the
output line 626. Thus, the logic signal on line
630 from the multivibrator 626 will initiate
tabbing of the carriage assembly 78 whether or not
.
(~ 117(~6(~0 ~-`
,. .. .. .
1 the latter is then setting upon a selected tab
location; then, although thellogic signal upon the
line 630 from the multivibrator 628 terminates
after the carriage assembly 78 has traversed about
one character space or a little more, the tab
sensing means 624 will not be producing a logic
signal upon its output line 626 while the carriage
assembly 78 is between selected tab locations,
which the invert input to the gate 632 utilizes to
continue its own logic output signal to the lines
634 and 614 until the carriage assembly 78 does
reach the next selected tab location, whereupon
the inversion of the logic signal from the line
626 causes the gate 632 to discontinue delivering
a logic out~ut signal to lines 634 and 614, so
that the carriage assembly 78 will stop at such
newly encountered tab location. It will also be
observed, of course, that the application of the
logic signal to the line 614 results in energi-
zation of the solenoid 102, and with a slightdelay, the solenoid 104 during the tabbing opera-
tion, for the purposes previously noted (including
the turning of the strip 160 serving as a "gover-
nor" to prevent undue speed of translation of the
carriage assembly 78 during tabbing).
Next, the carriage return function is
activated by the decode logic circuitry 516 de-
livering a logic control signal to its output
lead 522. Presentation of the logic signal
upon line 522 directIy initiates two actions.
First, it delivers a logic signal through the
Iine 636 and an isolating diode or the like 638
to the line feed initiate line 526, thereby causing
vertical advancement of the paper by one line in
the manner previously described for the line feed
. . .
~--` f 11~!600 ` f
- 56 -
1 function, it being noted that the mul~ivibrator 608
will for this purpose preferably either be of the
one-shot type or have a second half-cycle period
sufficient to permit completion of the carriage
return function without initiating a second line
feed function. Secondly, the logic signal upon
line 522 activates a one-shot multivibrator 640,
which delivers to its output line 642 a logic
: signal of sufficient duration for completion of
a norrnal carriage return operation. Left margin
sensing means 644 may be implemented in any con-
ventional manner, such as those previously men-
tioned for the tab sensing means 624, and operates
to present to its output lead 646 a logic con-
trol signal only when the carriage assembly78 is positioned in or returned to its leftmost
marginal position (which may be adjustable
through selective positioning of a portion of
the sensing means 644). The sensing output line
646 is coupled through an invert input with an
AND gate 648, and the line 642 from the multi-
vibrator 640 is coupled as a non-inverting in-
; put to the gate 648. By virtue of the inversion
. of the logic signal from the margin sensing line
25 646, the gate 648 delivers a logic output to
line 650 coupled with the line 606 that is effec-
tive to operate the electronic switching device
544 and energize the motor 80 whenever the multi-
r~ vibrator 640 is delivering a logic signal to its
. 30 line 642 and the marginal sensing means 644 is
,.~ indicating that the carriage 78 is not in its
left marginal position and delivering no logic
: signal to its output line 646; however, when the
carriage assembly 78 is at or has reached its left
,, .
' 35 marginal position, the inversion of the logic sig-
.,,
.,
' ~ 117(~6~0 (~`
1 nal then presented to the line 646 causes the gate
648 to discontinue the delivery of any logic signal
to its o~tput line 650, ther~by causing the motor
80 to remain or become deenergized. It will be
noted that, even when the carriage return function
is invoked with the carriage asse~.bly 78 already
at its left marginal position, a single line feed
operation will nevertheless occur, as is desir-
able in most applications. It will also be observed
that, when the carriage return function is in-
voked with the-carriage assembly 78 displaced from
its left marginal position, both the horizontal
return operation and the single line feed opera-
tion will be occurring concurrently, which con-
tributes to the overall speed of operation. Aspreviously discussed in connection with the mechani-
cal operation of the printing apparatus 30, it is
desirable that the solenoids 102 and 104 be ener-
gized in their usual sequence and remain energized
during the duration of a carriage return opera-
tion. This is provided for by means of a connec-
tion from the lead 642 to the lead 614 through a
lead 652 preferably including an isolation diode
or the like as at 654.
Finally, we reach the matter of character
printing control by the control circuitry 500. The
character designating code for the next character is
delivered via the line 518 from the decode logic
circuitry 516 to a first in first out type queing
buffer 656 whenever the buffer 658 receives a logic
signal via the line 530 for enabling the writing
of the code for another character into the storage
space provided by the buffer 656 (which prefer-
ably will provide storage for sufficient qued
character codes to achieve rollover characteristics
117~6(~0
- 58 ~
1 equivalent to 8 or more actuations of various charac-
ter keys 50 or the equivalent input from an alternate
data source 508). Whenever enabled to do so by a
logic signal applied to its control input line
658, the buffer 656 makes available the next charac-
ter code to a digital comparator 660 via a multi-
conductor line 662. Meanwhile, the count or position
sensor 472 previously referred to (and which may
preferably be implemented by conventional infra-red
or optical sensing components) for detecting the
passage of apertures 164 as the strip 160 is moved
will have been delivering and continue to deliver a
logic signal for each such aperture passage to an
incrementing and decrimenting counter 664 via a
lead 666. Also, the reset position sensing means
473, which may be implemented similarly to the
sensing means 472 but in a fashion to respond
only to passage of the unique "zeroing" aperture
167, is adapted to deliver a logic signal for re-
setting the counter 664 via a lead 668 wheneverthe aperture 167 is passed. Although such reset-
ting of the counter 664 is not theoretically
necessary, it is desirable to assure that the count
accumulated within the counter 664 and representing
the position of the strip 160 will be maintained
through frequent rechecking and resetting of the
counter should that become appropriate. The count
residing at any given time within the counter 664
and representing the current position of the.strip
160 is presented-to the digital comparator 660 on
a continuing basis via the multi-conductor line
670.
The digital comparator 660 operates on
a continuing basis to compare the binary or other
numeric equivalent value of the character code being
f
- 1~7C!6~0
- 59 -
1 presented to it from the buffer 656 with the then
current.position indicating ;count from the counter
664 and is capable of determining whether the
latter is greater than, less than or equal to the
character code from the buffer 656. In a sophisti-
cated implementation, it may be desirable to fur-
ther speed overall printing operation i.f the digital
comparator 660 is implemented in a way such that
it will determine not only mere numeric differences
between the inputs it is comparing, but will also
take into account in generating "greater than" or
"less than" output control signals whether it might,
because of a "zero crossing", most quickly move the
strip 160 in a direction not strictly correspond-
ing to the pure numeric equivalent differences inthe input signals being compared. That is, for
example, the strip 160 might be most quickly re-
positionable for a character having a code of 125
with the band 160 currently positioned at a count
of three by so controlling the movement of the
strip 160 to be in a "greater than" direction,
even though the numeric value of the count from
counter 664 is "less than" the character code
from the buffer 656. The comparator 660, can, of
course, be so implemented through conventional
techniques. For the sake of simplicity of present
explanation, however, it may merely be under-
stood that the comparator 660 will provide a logic
signal upon one or the other of its output lines
672, 674 or 676 which respectively represent
what may be referred to as a "greater than" sensing,
a "less than" sensing or an equality sensing, the
first two of which are to trigger movement of the
strip 160 in an appropriate direction for posi-
tioning the character selected by the code from
~ . .
- 60 -
1 the buffer 656 in a position for printing thereof.
The incrementing and decrementing counter 664 de-
rives a control signal from the line 672 via a
line 678 for causing the counter 664 to interpret
count pulses from the sensor 472 in a decrementing
sense when the comparator 660 is sensing a "greater
than" relationship, and a signal for causing incre-
menting operation of the counter 664 may similarly
be provided from the line 674 through a line 680.
When the comparator 660 senses a "greater than" re-
lationship, the logic signal upon line 672 will be
delivered through an A~ID gate 682 and lines 684
and 686 to the line 616 for energizing the sole-
noid 102 until movement of the strip 160 has caused
the count presented by the counter 664 to become
equal to the character code being received by the
comparator 660 from tne buffer 656, whereupon the
logic signal will disappear from line 672 and the
solenoid 102 will be deenergized. In similar fashion,
a logic signal upon the "less than" line 674 will
be delivered through an AND gate 688 to a lead 690
connected to the line 620 for energizing the sole-
noid 104. Which of the solenoids 102 or 104 is
energized, of course, determines the direction in
which the band 160 will be moved to properly posi-
tion the next character to be printed. When the
comparator 660 senses equality, such as when the
band 160 is already positioned with a particular
character in readiness for being reprinted, a logic
signal will be applied to the line 676 that is de-
- livered to an inverting input of each of the AND
gates 682 and 688. Thus, such connections to the
gates 682 and 688 assure that no logic signal re-
presenting equality will be present upon the line
676 during operation of the solenoid 102 or the
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- 61 -
1 solenoid 104 for repositioning of the strip 160.
On the other hand, the presence of a logic signal
upon the line 676 does actuate a one-shot multi-
vibrator 690 for a brief period of the order of 5
milliseconds to briefly energize the solenoid 102
during that interval through a control.path pro-
ceeding from the multivibrator 690 through a lead
692 and the lead 686 to the line 616. Since a
sensing of equality by the comparator 660 does
represent the achievement of proper positioning
of the part 160 for the printing of the particular
character which has been undergoing processing,
the logic signal presented upon the line 676 to
represent a sensing of equality if ultimately
used to trigger a multivibrator 694, which in
turn delivers a logic signal along the line 658
to the read enable of the buffer 656, so that the
latter will then commence presenting the next
stored character code to the comparator 660.
As with many details of the mechanical
aspects of the embodiment disclosed for illustra-
ting the invention, it will also be apparent that
the implementation of the control circuitry 500
may be modified in a number of ways without de-
parting from the real gist and essence of the
invention involved in the printing apparatus 30.
Accordingly, it is to be understood that this in-
vention should be deemed limited only by the fair
scope of the claims which follow, and that such
claims should be interpreted so as to encompass
a fair range of mechanical equivalents of the
subject matter defined therein.
.
.,
.,
.,
