Note: Descriptions are shown in the official language in which they were submitted.
~L3~S31~
PRINTWHEEL SETTING DEVICE FOR A POSTAGE METER
RELATED PATENTS
A patent which describes and claims related subject
matter ls U.s. Patent 4,876,956.
FIEhD OF_THE INVENTION
The invention relates to electronic postage meters
and mors particularly to so-called flat-bed printing
meters.
BACKGROUND OF THE INVENTION
Electronic meters of the flak-bed printer type are
well-known and are described for example in U.S. Patent No.
4,579,054, i~sued to Buan, et al., which shows a
stand-alone electronic mailing machine in which the
electronic postage meter forms an integral part of the
device. Aspects of such a stand-alone mailing machine are
described in U.S. Patents 4,535,407 and 4,523,523 among
o~hers.
Of particular concern in postage meters and mailing
machines developed for hiyh throughput is the speed with
which the printwheels can be ~et to a new value. U.S.
Patent No. 4,034,669 ~eaches the use of a separate stepper
motor for each printwheel in the printdrum of a postage
meter of the rotary press type. U.S. Patent No. 4,398,458
shows a setting device ~or the printwheels in a print drum
in which separat~ stepper motors are used for each
printwheel. U.S. Patent 4,451,053 descri~es a method or
the parallel setting of printwheels using a particular
~3~
Die protection assemblies incorporate various
mechanical arms or projections which protrude from the
printwheel area of the die in order to prevent a person
from simply placing an envelope against the die to
obtain an imprint.
U.S. Patent No. 2,795,186 issued to Bach shows a
movable shroud which can be lowered to guard the
printing die against taking unauthorized impressions at
any time between printing operations. The shroud
completely covers the face of the value printing die
when the printing mechanism is not in an operating
cycle and is locked in that position until the cycle
starts at which time the shroud moves to a position
uncovering the die. U.S. Patent No. ~,559,444 issued
to Erwin et al. teaches an interposer arrangement which
extends upward from the platen into the space into which
an envelope or other workpiece is to be inserted. These
interposers are moved out of the way during a legitimate
printing operation. The interposer blades are mechan-
ically linked to the inkin~ mechanism in order to movethe blades out of the way as the mailpiece moves into
position for imprinting. U.S. Patent 4,796,526 and
4,796,527 describe interposer devices which are linked
to the motor driving the platen of the printer to move
out of the way or actuated by a power switch to be moved
out of the way so long as power is applied to the machine.
While these known devices work well in the
particular environments in which the platen and the die
are not expected to be physically separated, in a
modular device where the meter with its secure die is
removable from the assembly where the platen is
retained, several new security issues are created in
respect of a flat-bed printer type of postage meter.
SUMMARY OF THE INVENTION
Th~ electronic meter in accordance with the invention
~3~ 36~
-- 3 --
is a flat-bed letter press prin'ing postage m~ter which is
removable from the mailing machine and in which there are
included novel die protection features to protect the die
when the meter is removed and the platen remains with the
mailing machine or base.
In a preferred embodiment, the postage meter in
accordance with the invention has three independent die
protection mechanisms to prevent the fraudulent "wipiny" of
prints. For best results, the meter will not actually
print, it will rather allow prints to be taken by the
mailing machine during a narrow time "window" when all of
the meter die protection is withdrawn.
In accordance with the invention, the first die
protector comprises a sliding plate which completely covers
the printing elements when the meter is removed from the
mailing machine. In a preferred embodiment, this plate
_ cannot be retracted unless the meter is in place on a
legitimate mailing machine. The second protector device
comprises die protector blades or interpo~ers which are
adjacent to two of the printwheels, preferably the higher
order printwheels. They are locked into a position which
causes them to protrude beyond the print surface anytime a
I retracting solenoid is unpowered. This mechanism protects
,. the die from print "wiping" anytime the meter is not
enabled and ready to print. The third protector mechanism,
called herein the aligner/protector mechanism, is similar
to ~his second, but it i~ separately ac~uated, and is
locked in place at all times except for a ~ime controlled
"window'l whe~ ~rinting takes place. It is anticipated that
accounting for p~stage would occur at the start of each
such "window".
When the meter is removed from its machine, all three
die protection mechanisms ar~ unconditionally in place, and
die access is not ~ossible for printing or a~y other
3s puxpose~ After installation on the machine, ~e pLotection
is sclectively removed as ~ollows:
1.) Suacessful installation retracts ~he die cover
plate;
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2.) When printing ellgibility conditions are
satisfied, that is, where there is adequa~e power and
sufficient funds and the like, the die protector blades
are retracted; and finally,
3.) The aligner/protector blades are momentarily
withdrawn only at the time of each accounting if the
necessary conditions are satisfied.
When properly installed on the mailing machine,
during all normal operations, the meter is in
communication with the mailing machine via a
communications channel. In a preferred embodiment, the
mailing machine will communicate a request that the
meter raise its die protectors/aligners so that a print
may be taken, and that a disable or "locked out" meter
can reject the request and prevent any attempts at
printing.
Other aspects of this invention are as follows:
A printwheel setting device for positioning a
printwheel of a postage meter comprising:
a print wheel having a plurality of printing
characters about the periphery thereof;
a motor;
a gear train drivingly connecting said motor to
said printwheel;
said gear train including at least one gear such
that a plurality of positions of said at least one gear
correspond respectively to a printing position of each
of the plurality of printing characters on said
printwheel;
means for determining the shortest path of rotation
of said at least one gear to place said at least one
gear into a position wherein a desired character on said
printwheel is in the printing position; and
means for operating said motor to move said at
least one gear wheel to said position along said
shortest path.
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4a
In a postage meter of the type having a printing
die carrying an indicia and printwheels for the printing
of postal value, means for setting said print~heels
comprising:
a plurality of printwheels each having respective
printwheels gears connected thereto;
a plurality of stepper motors having respective
stepper motors shafts, each stepper motor being
respectively associated with one of said printwheels;
each said stepper motor shaft having a pinion
carried thereon;
a plurality of transfer gears, each respectively
meshing with said printwheel gears;
gear means respectively connecting said transfer
gears and said pinions for driving said printwheels to a
desired position;
said transfer gears having a greater number of
teeth than said printwheel gears wherein a predetermined
position of the printwheel gears are associated with a
plurality of positions of the respective transfer gears;
means for determining the shortest rotation path
for the rotation of each trans~er gear to place the
printwheel in a desired position; and
means for driving said stepper motor as required to
rotate said transfer gear and thereby said printwheels
to said desired position.
BRIEF_DESCRIPTION OF T~IE DRAWINGS
Fig. 1 is an external perspective view of an
electronic meter in accordance with the invention.
Fig. 2A is a perspective vi~w of a meter in
accordance with the invention shown in position on a
mailing machine.
Fig. 2B shows one way of removing a meter in
accordance with the invention from the mailing machine.
Fig. 3 is a bottom view of the meter which shows
the sliding shutter that covers the die when the meter
is removed from the mailing machine.
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4b
Fig. 4A is a perspective view showing the print
die and solenoid-operated dead bolt with the sliding
shutter in the closed position. Other meter internal
assemblies except for the die are not shown for ease of
viewing.
Fig. 4B is a similar perspective view of the meter
as in Fig. 4A showing the sliding shutter in its
retracted position.
Fig. 5 is a side view of a first embodiment of an
operate-remove mechanism for attachment of the meter to
the mailing machine.
Fig. 6 is a side view of an alternative embodiment
of an operate-remove mechanism.
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Flg. 7 is a partially exploded view of a suitable
internal configuration of the meter ln accordance with ~he
invention.
Fig. 8 is a runctional block diagram of a
computerized postage meter.
Fig. 9 is a block diagram showing co~munication
between the mailing machine and the postage meter.
Fig. 10 is a flow chart of a suitable communication
routine for releasing ~he dead bolt to allow retraction of
the ~liding plate.
Fig. 11 is a side view of the printwheel setting
mechanism in the postage meter.
Fig. 12 is a section taken along the line 12-12 of
Fig. 11.
Fig. 13 is a section taken along the line 13-13 of
Fig. 11.
Fig. 14 is a section taken along the line 14-lq of
Fig. 11.
Fig. lS is an embodiment of a die protector
arrangement in which the die protectors are disposed
adjacent to the higher order printwheels.
Fig. 16 shows an embodiment wherein there is an
aligner/protector mechanism for the lower order
printwheels.
Fig. 17 is a flow chart for the operation of the die
protector blades for the higher order printwheels.
Fig. 18 is a flow chart for the operation of the
aligner/protector blades.
Figs. 19~ H comprise a flow chaxt for the
operation of the printwheel setting mechanism.
DETAILED DESCRIPTION OF THE DRAWINGS
In Fig. 1 there is shown as 10 an electronic meter
in accordance with the invention. The cover 12 of the
housing 14 holds a keyboard and display 16. The
keyboard and display are suitably similar to that shown
in U.S. Patent 4,097,923. Preferably, the keyboard is
of conventional monolithic type and the display is
liquid crystal with a capacity of twelve
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digits. It will be understood that the meter keys and
display of registers are not necessarily limited to those
shown in this re~erence and may be varied as desired in
accordance with the requirements of the meter. When the
meter 10 is installed on a mailing machine, the keyboard
and display may be hidden from view of the operator.
Fig. 2A is a perspective view of the meter 10
installed in a mailing machine or meter base 18. The
mailing machine 18 has schematically shown therein a
printing platen 20 reoiprocally driven by motor 22 through
rack and pinion mechanism 24. Lid 26 when closed during
normal operation will cover the meter. Feeder module 28
feeds mailpieces to the base 18 which transports the
mailpiece to the space between the print die 30 of the
meter which carries the meter indicia and the platen 20,
whereupon with upward reciproca~ion of the platen, an
. imprint of the indicia is placed upon a mailpiece such as
mailpiece 32 shown being ejected from the m iling machin~O
Platen drive arrangemen~s are well known and are
shown for example in U.SO 4,579,054 to Buan et al. and in
U.S. 2,795,186 ~o Bach et al, It should be appreciated
however that in respect of the meter in accordance with the
.j invention the platen 20 is a park of the base 18 and the
meter 10 includes only the print die 30. The mailing
machine will not be further described except as necessary
j for the description o~ the operation of the meter 10.
, In the preierred embodiment the print die is an
I elas~omer print die in order to obtain the best print
quali~y for a ~iven platen force. It will also be
appreciated as is well-known tha~ the print die ~ust be
inked in order to print the indicia. Inking mechanisms are
; known and are also shown in the previously cited patents o
Buan and ~ach. Preferably t~e inker ~echanism ~which is
not shown) ~lso remains with the base 18. It will be
understood that the inker oould be a part of the me~er
ins~ead.
Fig. 2B shows the meter being removably mounted on
the base 18. The meter is inserted in~o pocket 34 which is
pivotally mounted to the base 18. When the meter is
~IL3q~S~
inserted into the pocket 34 connector 36 in the pocket
mates with a corresponding connector 38 (not shown in Fig.
2B) on the meter 10.
The mating connectors 36 and 38 serve to enable
communication between the mailing machine 18 and the meter
10 and pxeferably carry power to the meter as well. A
suitable communication system is described in U.S.
4,301,507 issued to Soderberg et al specifically
incorporated herein by reference. The communication
hetween the units as described in this patent is serial
character asynchronous, bit synchronous, in message form,
with the bits of the messages being timed in accordance
with a given schedule ior synchronous control. It will be
understood that other communication procedures and devices
well-known in the art may be used in he alterna~ive if
desired.
i Turning now to Fig. 3 which sh~w~ a bottom view of
the meter, a sliding plate or ~hutter 40 is slidingly
mounted on housing I2 and is locked in the illustrated
closed position suitably by means of dead bol~ 42,
preferably ~pring-loaded, which extends into the hole 44 of
shutter 40~ The shutter is released by actuation o~
solenoid 46 (seen in the illustrated embodiment of Fig.4A
and 4B) but it will be unders~ood that means such as a
cam-actuated, motor-controlled locking mechanism may be
,j used in the alternative or ~n addition to such solenoid-
actuat~d deadbolt if desired.
Fig. 4A and 4B show perspective views of ~he meter
wi~h the shutter 40 shown covering the prin~ die 30 and in
the re~racted position with the print die exposed.
I~ order ~o prevent access to deadbolt 42 from the
out~ide, it will be under~tood that hole 44 m~y be a blind
hole or bore on the lnside o~ the shutter 40.
As previously noted, the m~ter in accordance with the
inven~i~n is a 1at bed printer wi~h elas~o~er printing
dies and that the platen and inking mechanism prcferably
remain with the mailing machine. In order to protect the
print die in this configuration, whenever the meter is
removed from the mailing machine, in accordance with the
3~
invention all of the printing elements are automatically
covered by the shutter 40. This shut~er which covers the
die is only retracted as discussed below when the meter is
in place on a legitimate mailing machine. The die cover or
shutter 40 is one of three independent die protection
mechanisrns in this meter.
It should thus be appreciated that the die would
~till be protected from the "wiping" or fraudulent ~aking
of prints by the other protection mechanisms. ~xposure of
the print die 30 however might still allow tampering to
alter some of the artwork of the indicia or allow damage to
occur or to expose the operator to ink from the die.
Fig. 5 is a side view of one embodiment of an
operate-remove mechanism for the meter. Carry handle 48
tnot shown in previous Figures) is pivotally mounted on
meter 10 at pin 50. Slot 5~ on the handle is operative to
engage a mating pin (not shown) on the base 18 when the
meter is pivoted downward as illustrated in Fig. 5 and the
handle 48 is rotated in the clockwise direction. It will
be understood ~ha~ at this juncture the meter 10 is
electrically connected to the meter base 18 through mating
conne~ctors 36 and 38 and is locked to the base by slot 52
engaging w$th the mating pin on the base.
~, With ~he meter and base operative, communication is
established and using appropriate "handshake" messages
I between the meter and ~he base it is determined that a
proper me~er i~ in the home position on a le~itimate base.
Accordingly, deadbolt 42 (not shown in Fig. 5) is
retracted, preferably only or a predetermined length of
~ime. With ~he dead~olt retracted, the shutter 40 may be
moved rearward (to the righ~ in Fig. 53. In the
illustrated embodiment, this is accomplished by means of
the flexible cable 54 having handle S6 for grasping by the
operator. The ca~le is suitably mounted on the pocket 34
by any convenient means (not shown~. The other end of the
cable is connected to pull slide 58 sli~aably mounted on
the base 18 ~y any convenient ~eans (also not shown)~ The
side wall 60 carries pin 62 and pin 64. With the meter in
the home position, that is in the lower position
:lL3~
illustrated, pin 62 engages slot 66 of slid~ pull 58. When
the slide pull 58 is moved by the operator pulling forward
on the flexible cable, the shutter 40 will also be
retracted to uncover the print die shown at 30.
As shutter 40 moves, pin 64 will interlock with slot
66 of the carry handle 48 to prevent the meter from being
lifted from the operating position when the shutter is
retracted. Thus in order to remove the meter 10, The
operator must push the flexible cable inward to push the
shutter 40 into position again covering the print die 3Go
The deadbolt 42 is spring-loaded and re-engages the hole 42
in the shu~ter to lock the shutter tn secure position.
Other methods and apparatus may be used for the
purpose of retracting the shutter. Fig. 6 shows an
alternative embodiment where the meter is installed by
lowering it vertically into the base. In Fig. 6 the
- mechanism is shown in mid-position after the meter has been
installed and locked in position but prior to the
retraction of the shutter mechanism.
The meter shown in this embodiment is placed
vertically downward on the ba~e with square pin 100 on the
meter being to the front of the meter and pin 110 sn handle
120 ~lear for up and down movement oi the meter from ~he
base. The cam surface 130 on the meter captures the pin
110 and as the lever is pulled by the operator toward the
front of the meter the vertical slot portion of the cam
surface 130 is pushed toward the operator so that pin 100
is engaged i~ slot 140. At this point the meter is locked
in place and co~munication be~ween the met0r and the base
is e~tablished as de~cribed in connection wlth Fig. 5.
With the appropriate ~'handshake~' the deadbolt is raised to
a~low further moveme~t s~f the handle. Pin 160 which is
mounted on the shut~er h1s also moved into contact with
wall 170. Pre~erably, a lip or angled member sh~wn at 200
3S also enga~es a slot 210 to lock the me~cQr to the base.
As the handle 120 moves further forward, ~ector 220
engages pinion 230 which drives rack ~40 affixed ~o member
260 t~at carrles wall 170. The shutter plate is moved
rearwardl~ hy act~.on of wall 170 on pin 160 until the
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-- 10 --
handle is stopped by the cam surface 130 and the shutter
has exposed the print die.
Other means for locking the meter in place and for
actuating the retxaction of the shutter can be envisioned
5depending in part on the way the meter is required ~o be
installed. It will be understood that the various
operations for retracting the shuttex described herein as
performed by the operator can be motorized if desired.
Fig. 7 shows a partially exploded view of a meter in
10accordance with the invention. The meter lQ is shown with
the cover 12 and keyboard and display raised from the
bottom to expose a schematic layout of the meter hardware.
The connector 38 ~eeds into the printed circuit boards 300
which comprise the accounting and printin~ control
15funct1ons described below. The print wheels 310 are set by
stepping motors 3Z0 in an arrangement also described
-helow. A dater assembly 330, PIN counter 340 and a slogan
printer 350 are also provided as required. Preferably, a
¦door 360 provides access as necess~ry ~o the slogan, PIN,
and date ~rinters.
Fig. 8 is a func~ional block diagram of a
computerized postage meter. The system is controlled by a
; microproces~or which basically comprises a CPU which
perfonms ~he functions of accounting, controlling the
25setting of the printwheels, die protection and the
~communication wi~h the base and other peripherals as
-required. Three types oi memory units are employed with
the CPU. The permanent memory PM which may be a ROM or
PROM stores the sequence of program operations to be
performed by the CPU for its accounting calculations and
control functions. The ~emporary memory TM which is a
working ~AM holds the data and calculation results on a
~emporary basis u~il they are stored in the non volatile
memory NVM. The non volatile memory can be battery-backed
RAM, ~EPROM, E~ROM, or MNOS as desired or any-combination
if two or moxe memories are utilized. Pxe~erably, at least
two nonvolatile memories are used and transaction
accounting data is stored in nonvolatile memory for each
transaction. A suitab].e method for such accounting i9
shown in U.S. Patent No. 4,484,307. Other accounting
methods are described in U.S. Paten~ No. 3,978,457. Funds
may also b~ placed in cr removed from memory by means as
described in U.S. Patent No. 4,097,923.
The system in accordance with the invention may
operate in accordance with data input through the keyboard
and display 16 and displays information on the same or it
receives and transmits information to the mailing machine
or other peripheral through connector 38 as shown in Fig.
9. The meter keyboard and display in a preferred
embodiment would be useable only for the purpose of reading
the various meter registers and/or for the purpose of
refunding the me~er and for various checks and accounting
operations which may be required when the meter i.s not
installed on its base. When the meter is installed on the
base, the CPU in accordance with the data it receives from
the base, operates the steppiny motors 320 or setting the
printwheels 310 shown in this Figure as the setting postage
block SP and also controls the other die protector devices
to allow the printing of postage to take place. These
operations are indicated at the postage printing block PP.
Fig. 9 shows a block diagram of the ~o~munication
between the meter a~d mailing ~Achine.- As me~tioned
previously it is preferred that all the communication be by
way of the protocol described in U.S. 4,301,507.
Fig. 10 i~ a flow chart ~or the releasing of the
de~dbolt 42 to allow the shutter to be retracted. Once it
has been determined that the meter is on an appropriate
base, the solenoid is actuated for a predetermined amount
of time to allow the operator to move the shutter.
Figs. 11-14 ~how the printwheel setting mechanism.
The printwheel setting mechanism comprises five motor
driven gear trai~s. Five stepper motors ~each designated
320 ~ince the drive trains are similar for each printwheel)
are mounted on w~lls 40~ each motor respec~i~ely driving an
associa~ed printwheel 310 via respective motor pinions 410,
encoder assembly gears 420, transfer gears 430, and
printwheel gears 440 attached to the prin-twheels 310. Each
~3~
- 12
gear train includes a two-channel encoder sensor assembly
designat~d herein as 480. The encoder assembly gears 420,
suitably of molded plastic, include ten (10)-tooth gears
which mesh with the transfer gears 430 and twenty
(20)-tooth gears that mesh with the motor pinions 410 along
with the planar wheel portions which extend into the sensor
assemblies 480.
Each sensor channel comprises a source, suitably an
infrared-emitting diode and a detector, a photodiode with
its associated circuitry. Such sensors are conventional
and will not be further described.
! Preferably the encoder wheel operates to produce ten
(10) transitions per revolution as the encoder wheel passes
through the sensor assembly and in each sensor channel
alternately blocks and unblocks the radiation from the
source. This results in two (2) sensor detector
transitions (one for each channel of the two-channel
r~ sensor) for each move of one-digit.
~ The channels are physically separa~ed sl1ch that as
1 20 the e~coder wheel rotates the deteator outputs are in phaseguadrature (the output o~ one of the two dete~tors leads or
lags the ou~put of the other detector by one guarter o~ a
cycle).
The motor pinions 410 are ~welve ~12) tooth gears
.. 25 affixed to the motor shafts a~d mesh with the twenty (20)
too~h gears of the encoder gear 420.
Th~ stepper motors 320 turn ~hrough a complete
revolution in 24 steps which, as transmitted through the
~ear train previously described, require 4 mo~or steps for
movem~nt of one digit of the printwheel. In this
embodiment, the ~tepper motors are four-phase motors
preferably driven by the driver~ in a two-phase modeO The
motor control se~uence is discussed below in conjunction
with the flow char~s or the printwheel ~et~ing.
Ea~h p~intwheel 320 is suitably a plastic -omponent
which forms a substrate for the molded rubber print
characters located around the periphery of the wheel, one
of which is designated 450. The printwheel also comprises
ten (10)-tooth printwheel gear 440 which is used also as
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- 13 -
described below for alignment of the printwheel ~hen
printing takes place.
It will be understood that the setting mechanism
further accommodates shifting of the decimal point between
the middle digi~ printwheels and th~ lsast significant
digit printwheel to ob~ain various postal values as
required.
The transfer gears 430 are thirty (30)-tooth gears,
suitably of molded plastic, that mesh with the printwheels
gears 440 and the ten (10)-tooth gears of the encoder gears
420. The transfer gears 430 include a protrusion 460 which
in conjunction with a fixed feature 470 on the housin~
provides an end stop or zero-reference position for the
mechanism.
When the transfer gear protrusion 460 is adjacent the
~top 470 that there is a known fixed value on the print die
plane. It will be appreciated that with thirty (30) teeth
on the transfer gear meshing with the ten (10)-teeth on the
printwheel gear there will be three (3) rotations of the
printwheels f or one rotation of the transfer gear. ~ecause
of the particular implementation of the end stop, there are
in this embodimenk twenty-six (26) transfer gear positions
which correspond to t~e 10 digit position of the
printwheel. In accordance with the invention, advantage is
taken of the fact that ~ particular digit setting is
available at a plurality of transfer gear positions in
order to achieve the 6hortest pat~l movement o~ the transfer
gear to achieve ~etting of t~e required character on each
printwheel.
In the ~mbodiment shown in these Figures, a single
~olenoid 490 raises die protector blades 495 in tande~ to
~; enable ~he printing o~ postage. While this arrangement
I nor~ally ~orks well in conventional flat bed printers,
th~re is further pr~vided in tha postage meter in
accordance with the present inventlon further die
protection as ~own more particularly in conjunction with
Figs. 15 and 16~ .
Fig. 15 i~ a perspective view ~f the die protector
mechanism. In accordance with the present invention, two
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- l4 -
die protector blades 500 and 510 ar~ placed adjacent to the
two highest order printwheels of the printwheel banks 310.
When the meter is logically incapable of accepting a print
re$uest, these two blades protrude beyond the printing
plan~ of the print elements to pravent the "wiping" of
fraudulent prints from the die.
Particular conditions under which, for example, the
meter may be disabled include lack of power, insufficient
- funds, value selection in progress in which the higher
order printwheels are to be moved, and various sensed error
condition~.
¦ As is shown in Fig. 15, blades 500 and 510 are
pivotally attached at shaft 520 and at the opposite end are
engaged via pin 530 which ls held in S-shaped slot 540 of
member 550 to the armature 560 o~ solenoid 570. The
solenoid 570 is under the direct control o~ the
u. microprocessor. When the solenoid is energized it pulls in
B .~
the member 550 against the force of a spring (not shown)
and the elevated portion of slot 540 raises the diP
: 20 protector blades. The die protector blades will remain
retracted until the microprocessor de-energizes the
solenoid or until power is lo~t. When the die protector
., blade6 are xetracted, they perform the alternate function
~! of detenting the two higher order print wheels to improve
their alignment.
Fig. 16 shows an additional die protector mechanism
, which comprise a set of pro~ruding ~ie protector blades,
i called here alignerfprotector blades which are retracted
for only a brie~ interval during each print op~ration.
; 30 Preferably this re~raction coincides with the meter
accounting operatio~. In accordance with the invention,
these aligner/prote~tor ~lades shown at 602, 610, and 620
are disposed ~ex~ to the lower order prin~wheel~. ~he
~hree blades are normally locked in position as shown
suitably by ~rojecting tooth 630 vr rotatable cam 640.
Solenoid 650 whe~ actuated rota~es cam 640 to move tooth
630 out of the way and to raise the aligner protectors by
engagement of the tooth 660 on cam 640 with tooth 670 on
the die protector blades. The rotation of cam 640 is also
3L3C~aS3~
- 15 -
against a spring ~not shown~ so that in the event of
failure the cam will return to the locked position.
It will be appreciated that the actuation of these
two types of die protection may be by way of either type of
5mechanism described herein and is not limited to either
method so long as the locking is achieved.
- For operation, the three blades are normally locked
in the protruding position and external forces cannot cause
them to retract. When the mailing machine co~nunicates a
10request to print an imprint, the meter will consider the
re~uest and on the basis of availability of funds and other
printing criteria, ~nd if accepted will energize the
solenoid and withdraw the aligner/protectors for a timed
period ln which the mailing machine can lnk the di,e and
15take the print. Preferably, the aligner/protectors have
the auxiliary function of detenting ~n~ aligning the lower
order printwheels.
Figs. 17 and 18 are flow charts for ~he operation of
the die protector and the ali~ner/protector mechanisms.
20The operation of each has been described and it is not
believed to be necessary to describe the flow charts in any
greater detail.
~Figs. l9A-19H show the operation of the print wheel
`;,setting mechanism shown ~nd des~ribed in conjunction with
Figs 11-14. The flow chart shows the operation of the
~,"me~hanism to enable advantage to be taken of the shortest
path to the new ~etting. This is of great benefit to the
increased setting speed reguired for the throughput of a
meter in accordance with the invention for minimizing power
30comsumption.
Fig. l9A shows the normal set postage routine for
setting the printwheels of the postage meter. In
accordance with this routine, a success flag is first
cleared and a flag indicating whe~her the posi~ion o~ the
35printwheels is known is checked. ~f ~he ~osit~or.-known
flag is set, a software initialization routine is called.
A subroutine SDIGITS calculates the digit distance for all
five banks of printwheels and when this calculation is
comple~e a set postage routine, SSTEP, is called. At the
~3~ 31~3
- 16 -
end of the setting routine, the position is again checked
and if it is known the success flag is set.
Fig. l9B shows the subroutine SDIGITS which computes
the distance and direction that each di~it wheel must move
by subtracting the value of posta~e currently set, stored
as old value from the desired value stored as new value.
As mentioned in the discussion of Figs. 11 through 14, each
printwheel character printin~ position is associated with
multiple transfer gear se~ting positions. Thus in
accordance with the routine, except when the meter setting
mechanism is being initialized, ten (10) is added to the
new digit to place the new number in the center decade oE
the transfer wheel. The value presently set in the
printwheel is subtracted from the new value thus obtained
to get the difference (DIFF). The sign resulting from the
subtraction is also stored to determine the direction ~he
printwheels must move.
A test is then made as to whether initialization is
being done. If yes, the routine returns to the ~ain loop.
¦ 20 I~ initialization is not keing done, the DIFF is tested to
see whether it is greater th2n five (5). If DIFF is equal
to or less than five ~5) the program returns to the main
loop. If the ou~come of a test shows that the difference
is greater than iive ~5~, DIFF is tested again for bei~g
~reater than, equal to, or less than ten (10). If the
i outcome is equal to ten (10), DIFF is made e~ual to zero
~0) and the program returns to the main loop. If greater
than ten (10), ten (10) is subtracted from the difference
and the result is again tested. I DIFF then is less than
ten (10), the direction is tested to see whether the
printwheel6 are to move up or down.
If the wheel is to move up, the set value plus ~ten
minus DIFF) is ~ested and i~ less than or egual to
twenty-six (26~, the direction is reversed and DIFF is set
equal to ten (101 minus DIFFI Ii no, the prooram ret~;ns
to the main loop.
~f the printwheel direction is down, then set value
minus ~10 minus DIFF) is tested as being greater than or
equal to zero ~0) and if it is then direction is reversed
3~S~
- 17 -
and DIFF is set equal to ten (10) minus DIFF. If no, the
program returns to the main loop.
Fig. l9C shows the subroutine SSTEP. This subroutine
will move the printing wheels by the number of digits
specified in the SDIGITS program ancl in the direction
specified in that subroutine. In this subroutine, the
position known flag is eleared and the number of motor
steps required are calculated by mu:Ltiplying the digit
- distance by four (4) since the stepper motor moves four (4)
steps for each digit. The wheel position in sensor
transition is also calculated as two ~2) times the set
i value. This is determined for each bank. ~t this
juncture, the subroutine SMOTOR is called to provide the
step pulses to the stepper motor to drive the prlntwheels.
The digit wheel position is aalculated from the wheel
position in sensor transitions which have been kept updated
through the move, divided by two (2), since as mentioned
previously there are two (2I sensor transitions per digit.
The calculation is checked to see if its an exact multiple
of two ~2) and if not, an error routine i~ called. If yes,
the set value is stored. A routine then follows to check
whether the ~etting $s initializing and if not, ~he prin~
value is set equal to the set value. The prink value is
checked to determine whether it is greater than or egual to
ten (10), if it ls, the print value is made equal to the
print value minus ten (10) and again checked.
If the print value is less than ten (10~, the routine
. proceeds to check whether the pri~t value now equals the
l new value and if not, an error ro~tine is called. If the
answer i~ yes, the subroutine determi~es if ther~ are any
remaining banks to be set. If there are, the wheel
position for the next b~nk is check~d until no banks remain
to be checked. The position known flag is set before
~ returningO
Fig. l9D shows the subroutine S~OTOR f~r provid-.... g
step pulses to each motor. Each motor is provided output
on a seguential basis during the se~ting cycle for the
printwheel banks. For each bank then the motor steps are
checked and i~ they are greater than zero (0) then an
~3~LS;3~
- 18 -
output is set for the motor to move one (1) step and an
"output ready" 1ag and "waiting for timer" flag are set.
The sensor monitoring routine SSENDS is called and a check
is made as to wheth~r ~nother bank is req~ired to be set.
If at the check for motor steps, the bank shows zero
(0) steps to do, the program branches to set up data for
present position holding coil and a holding counter is
decremented. If the coun~er has not reached zero (P~ the
program returns to the main loop of SMOTOR and the "output
ready" flag and "waiting for timer" flags are set and the
sensor monitoring routine is again called. If the counter
has decremented to zero (0), then the flag ~s set for
zero (0) and the "waiting for timer" flag is set with no
"output ready" flag. The program operates until all the
zero (p) flags are set at which point it returns to the
main loop.
Fig. l9E shows the subroutine SS~NDS which monitors
the sensor channels to update ~he actual positions of ~he
whe l. In this subroutine, each bank sensor is read and it
is determined whether a transition has been made. If the
answer is yes, the direction is determined by checking the
transition sequence of the two ~hannel sensor and if the
direction i~ down, one is subtracted from the wheel
position and if the direction is up, one is added to ~hs
wheel position. ~t this point the "waiting for timer" flag
is checked and if it is clear the program returns. I the
waiting for timer flag is not cleared then the next bank is
read.
If no transitions were detected then the "waiting for
ti~er" flag clear is checked. And if cl~ared, the program
returns.
Fig. l9F shows the timer interrup~ routine.
Fi~. l9G ~hows the subrou~ine for initializi~g the
printwheels. In this routine, th new value is set equal
to ~wenty-six (26) for each wheel and the transfer gear is
driven all the way to the stop. At this point, the
"position known" flag is checked and if ~he "position
known'l ~lag is not set, the set value is set equal to all
~3~S31~3
-- 19 --
zeros t0's~. If the position known flag is set, the step
of making all zeros (0's) is skipped.
The initialization flag is then sst, the common
initialization routine is called and the subroutine
proceeds to check the printwheel positions at the middle
and opposite end. At this point, the current set postage
is set equal to zero (~) and the position known is tested
- and if the position is known, the success flag is set. If
not, the succe~s flag is not set and in both instances the
program returns to the main loop.
Fig. l9H shows COMIN, the subroutine for common
initialization. ~his routine is common to all motor
hardware drivers and it initializes the registers and sets
up the timer for in~erruption at predetermined times.
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