Note: Descriptions are shown in the official language in which they were submitted.
,~~:~(?~1~.o3e?~
C-426
IMPROVED PLATEN MODULE
Background of the Invention
This invention is generally concerned with printing
apparatus for marking letters and more particularly with
flat bed printing apparatus for marking letters including
envelopes, stuffed envelopes, irregularly-shaped letters
and letter mail, including self-mailers and stepped mail.
A significant proportion of the approximately one-half
billion irregularly-shaped letters, flats, parcels, and
l0 other irregularly-shaped mailpieces, such as stepped letter
mail, hotel keys, bagged film and the like, which are
annually received by the U.S. Postal Service for process-
ing, must be manually processed due to the lack of auto-
mated equipment. In the case of stepped, and other irregu-
15 larly-shaped letter mail, automatic separation equipment is
available for separating such mail from the main stream of
incoming mailpieces, but there has been a long felt need
for reliable machinery for handling other processing tasks.
In particular, manual processing is heavily relied upon for
20 performing such funct9.ons as cancelling the postage of
stepped and other irregularly-shaped letter mail, and
marking the same with appropriate destination bar codes for
subsequent sorting. Moreover, the marking function imple-
mented in the course of processing irregularly-shaped
25 letter mail ranks amongst the highest of the labor inten-
sive activities engaged in by Postal Services on a world-
wide basis.
Of course, large private mailers of stepped and other
irregularly-shaped letters are similarly burdened with
30 labor intensive processing activities, including applying
addresses, postage indicia and bar codes to such letters
for delivery to the Postal Service.
CA 02000132 1999-09-24
For marking letters, such as envelopes, stuffed envelopes,
irregularly-shaped letters and letter mail including self mailers and stepped
mail, mailing machines have been provided with postage printing apparatus
which includes indicia marking structure and platen structure including a
platen having an elastomeric member mounted thereon. To accommodate
marking letters of varying thicknesses fed to the platen structure, the platen
is lowered to receive a given letter on the elastomeric member, and then
raised towards the indicia marking structure for marking the letter.
Moreover, thermal transfer printing apparatus of the type which
includes a thermal printhead and thermal ink transfer ribbon, has been
provided with a flexible roller for applying backing pressure to a letter fed
between the ribbon and roller as the thermal printhead heats and applies
pressure to the ribbon for transferring ink from the ribbon to the letter for
marking the same.
The flexible roller embodiments shown in the aforesaid Murphy et al
Application include those having a cylindrically-shaped body portion provided
with one or more channels extending thereinto from the outer surface of the
body portion, as a result of which a plurality of spaced apart portions of the
roller body portion contact a given letter fed to the thermal printer along a
line extending
-2-
CA 02000132 1999-09-24
transverse to the path of travel of both the thermal ink transfer ribbon and
the given letter. And, one of the roller embodiments shown in the Murphy et
al Application has a cylindrically-shaped roller body portion including one or
more apertures formed therein and extending longitudinally of the length of
the roller body portion.
It has been found that the printing quality of printing on letters,
including envelopes, stuffed envelopes, irregularly-shaped letters and letter
mail, including self mailers and stepped mail, in a flat bed printer, is
enhanced by providing an improvement in the platen member mounted on
the platen of the platen module. The improved platen member is preferably a
resilient member, made of an elastic material, and includes a plurality of
intersecting channels which extend upwardly from the inner surface of the
member, rather than downwardly from the outer surface of the member,
whereby the member does not include the spaced-apart letter contacting
portions. Moreover, it has been found that since the flexibility of the
improved member in a flat bed printer affords the application of varying back
pressure, against the printing die of the postage metering module, the grey
scale level of the print on letters is substantially completely uniform.
Accordingly:
An object of an aspect of the invention is to provide apparatus for
enhancing the printing quality provided by flat bed printing apparatus;
Another object of an aspect of the invention is to provide improved
apparatus for marking letters;
Another object of an aspect of the invention is to provide apparatus
including improved means for resiliently urging a letter into engagement
with a printing die;
- 3-
CA 02000132 1999-09-24
Another object of an aspect of the invention is to provide means for
variably, resiliently supporting letters against the force exerted thereon by
a
printing die;
Another object of an aspect of the invention is to provide a reciprocable
platen, having a resilient, channeled, member mounted thereon, for use in
flat bed printing apparatus;
Yet another object of an aspect of the invention is to provide a platen
assembly which includes a pair of rack gears, a platen integrally connected to
the upper ends of the rack gear and supporting structure extending between
the rack gears, which are manufactured as a single piece part, in combination
with a resilient platen member according to the invention; and
Another object of an aspect of the invention is to provide flat bed
printing apparatus which includes a flexible member, having a plurality of
intersecting channels formed therein, mounted on platen which is
reciprocable for movement of the member toward and away from a printing
die.
Summary of the Invention
Therefore, various aspects of the invention are provided as follows:
In a platen module including a plate, means for supporting the plate
for reciprocable movement thereof, a platen member including an inner
surface thereof faced toward and fixedly connected to the plate for movement
of the platen member therewith, and the member having an outer surface
thereof faced away from the plate, an improvement comprising:
~ a. platen means including the platen member, the platen member
made of a resilient material;
~ b. the platen member including a plurality of channels extending
-4-
CA 02000132 1999-09-24
thereinto from the inner surface thereto; and
~ c. the platen means including a strip of substantially inflexible
material embedded in the platen member from the outer surface
thereof; and
~ d. the platen member including opposed longitudinally-extending side
edges and opposed transversely-extending end edges, the channels
including a first plurality of parallel-spaced channels extending into
the member from one of the side edges thereof and a second plurality of
parallel-spaced channels extending into the member from one of the
end edges thereof, the first channels intersecting only said one side
edge and each of the second channels, and the second channels
intersecting only said one end edge and each of said first channels,
whereby said platen member includes a longitudinally-extending
marginal portion and a transversely-extending marginal portion.
In a platen module including a plate, means for supporting the plate
for reciprocable movement thereof, a platen member including an inner
surface thereof faced toward and fixedly connected to the plate for movement
of the platen member therewith, and the member having an outer surface
thereof faced away from the plate, an improvement comprising:
~ a. platen means including the platen member, the platen member
made of a resilient material;
~ b. the platen member including a plurality of channels extending
thereinto from the inner surface thereof;
~ c. the platen means including a strip of substantially inflexible
material embedded in the platen member from the outer surface
thereof; and
~ d. means for venting air from an at least one of said channels when the
platen member is subjected to a force urging the outer surface towards
the inner surface, and the air venting means includes a plurality of
_ga_
CA 02000132 1999-09-24
apertures formed in the plate.
In a mailing machine including a plurality of modules, wherein one of
said modules is a printing module having a printing die and another of said
modules is a platen module having a platen member, and wherein the platen
module includes means for supporting the platen member for reciprocable
movement toward and away from the printing die, an improvement
comprising:
~ a. the platen member made of a resilient material and including an
outer surface faced toward the printing die and an opposed inner
surface fixedly connected to the supporting means for movement of the
platen member therewith; and
b. the platen member including a plurality of intersecting channels
extending thereinto from the inner surface thereof.
-4b-
;~a~t~c)~~~
Brief Description of the Drawings
As shown in the drawings wherein like reference
numerals designate like or corresponding parts throughout
the several views:
Fig. 1 is a schematic partially fragmentary, perspec-
tive view of a mailing machine including a platen module
including a platen having mounted 'thereon a resilient
platen member according to the invention;
Fig. 2 a.s perspective view of the flexible member
shown in Fig. 1 showing details of the intersecting chan-
nels formed therein from the lower surface thereof; and
Fig. 3 is a side view of a portion of the platen
module and printing module of Fig. 1, showing a letter
urged, by the platen member according to the invention,
into printing engagement with the printing die of the
printing module.
Description of the Preferred Embodiments
As shown in Fig. 1, a mailing machine 10 of the type
which may be improved in accordance with the present
invention includes a base 12, and, conventionally removably
connected to the base 12, a postage metering module 14,
inking module 16, platen module 18, scale module 2o ana
letter transporting module 22.
The postage metering module 14 (Fig. 1) includes a
conventional housing 24, and includes a plurality of
printwheels 26 which are suitably connected to the housing
24 for rotation relative to the housing 24. Each of the
printwheels 26 includes a plurality of fonts 28, wh7.Ch are
located at spaced intervals along the outer periphery of
the printwheel 26. In addition, the postage metering
module 24 includes print wheel indexing structure 30,
including a plurality of gears 32, one of which is shown.
Each of the gears 32 is operably connected on a one-for-one
basis to each of the printwheels 26, and is conventionally
- 5 -
CA 02000132 1999-09-24
driven by the indexing structure 30 for independently indexing the
printwheels 26 to selectively locate any given font 28, of any given
printwheel 26, in a printing location situated along a line 34 extending
parallel to the rotational axis 36 of the printwheels 26. The post~:ge
metering module 14 also includes printing structure 38 which includes a
plurality of fixed printing elements 40. The printing elements 40 are
located in a flat plane extending through the printing location of the
aforesaid selectively located fonts 28, when such fonts 28 are situated in
their printing location, whereby such fonts 28 and printing elements 40
collectively form a printing die, 28, 40. The printing structure 38 may also
include an additional set of printwheels 26, each including a plurality of
fonts 28, for date printing purposes.
The inking module 16 (Fig. 1) includes an ink bearing member 42,
which is movable into and out of engagement with the printing die, 28, 40,
when the selected fonts 28 are situated in the aforesaid printing location,
for applying ink to the printing die, 28, 40, prior to each printing cycle.
The scale module 20 (Fig. 1) includes a horizontally-extending deck
44 for receiving letters 46 fed to the mailing machine 10. The letters 46 may
be envelopes, stuffed envelopes, irregularly-shaped letters or letter mail,
including self mailers or stepped mail. Thus a given letter 46 may include
either a longitudinally-extending step or ridge 47A, or transversely-
extending step or ridge 47B, or both. The deck 44 has a rectangularly-
shaped aperture 48 formed therein, which is partially defined by a
forwardly located, longitudinally-extending, edge 50. In addition, the deck
44 has a plurality of smaller,
T~~ T~
2~~t~(I~..~~
rectangularly-shaped apertures 52 formed therein at spaced
intervals situated along a line (not shown) which extends
parallel to the aperture edge 50. The scale module 20 also
includes a bar 54, which overhangs the deck 44 and has a
plurality of slots 56 formed therein at evenly spaced
intervals along the length of the bar 54. Further, the
scale module 20 includes a plurality of ski-supporting arms
58. The upper ends of the arms 58 are located on a one-
for-one basis within the slots 56 and are conventionally
pivotably attached to the bar 54. The scale module 20
additionally includes a plurality of coil springs 60 which
are suitably connected to the upper ends of the ski-sup-
porting arms 58, on a one-for-one basis, and to the bar 54,
for resiliently urging the lower ends of the arms 58
towards the deck 44. Moreover, the scale module 20 in-
cludes a plurality of upwardly curved ski members 62 which
are connected to the lower ends of the ski supporting arms
58, on a one-for-one basis, such that the ski members 62
overhang the deck apertures 52 on a one-for-one basis.
The transporting module 22 (Fig. 1), includes a first
plurality of rollers 70, which are rotatably supported at
spaced intervals beneath the deck 44, such that their
peripheries respectively extend upwardly into the deck
apertures 52 on a one-for-one basis when the rollers 70 are
rotating in one direction. In addition, the rollers 70 are
suitably mounted to permit their being lowered in response
to rotation thereof in the opposite direction. Further,
the transporting module 22 including a second plurality of
rollers 72, which are rotatably supported at spaced lriter-
vats beneath the deck 44 and below the level of the first
rollers 70. The transporting module 22 also includes an
endless belt 74 which is alternately looped about each of
the first and second rollers, 70 and 72, whereby the belt
74 protrudes through the deck apertures 52, when the
rollers are rotating in the aforesaid one direction ana
does not protrude through the deck apertures 52 when the
rollers 70 are rotated in the opposite direction. Further,
the transporting module 22 includes driving structure 76
2~~~ ~~)9~_~3~
for moving the belt 74 in one direction about the first
rollers 70 for engaging and feeding a letter 46 which is
fed to the deck 44, and for moving the belt 74 in the
opposite direction, whereby the rollers 7o and thus the
belt 74, are lowered for disengaging the belt 74 from the
letter 46 to thereby position the letter in a predetermined
location on the deck 44. A more detailed discussion of the
structure of transporting module 22 may be found in the
aforesaid Abellana et al Application.
According to the invention, the platen module 18 (Fig.
1) includes framework 80 which is conventionally removably
attached to the mailing machine base 12, for removably
connecting the platen module 18 to the remainder of the
mailing machine 10. As thus mounted, the framework so
includes a horizontally-extending base plate 82, and
includes a pair of oppositely-spaced, upright, members 84,
each of which has an inner surface 86. The inner surfaces
86 face each other and are vertically oriented parallel to
one another. The upright members 84 each include a verti-
cally oriented channel 88, which is formed in the member 84
from the inner surfaces 86 thereof. The channels 88 are
each U-shaped in transverse cross-section and spaced-para-
llel to each other, such that the longitudinally-extending
openings into the channels 88 are oriented in facing
relationship with respect to each other.
The platen module 18 (Fig. 1) additionally includes a
drive motor 90 having a housing 92 which is conventionally
connected to the framework 80. The motor 90 includes a
horizontally-extending output shaft 94. In addition, the
platen module 80 includes an output drive gear 96, which is
conventionally fixedly mounted on the motor output shaft
94, and includes first, second and third pinion gears,
respectively designated 98A, 98B and 98C. Further, the
platen module 18 includes a horizontally-extending pinion
gear shaft 100 on which the gears 98A, 98~ and 98c are
conventionally fixedly mounted, at spaced intervals along
the length of the shaft 100. The pinion gear shaft 10o is
8 _
suitably rotatably connected to the framework 80, such that
the pinion gear 98A is disposed in meshing engagement with
the drive gear 96. Further, the platen module 18 includes
a pair of vertically oriented rack gears 110 which are
spaced parallel to each other. Moreover, the platen module
18 includes rack gear supporting structure 112, preferably
a strut in the form of a wall, which extends between and is
fixedly connected to the rack gears 112. The rack gears
112 are disposed in sliding engagement with the upright
numbers 84, on a one-for-one basis, as hereinafter dis-
cussed in greater detail. As thus disposed, the rack gears
110 are also disposed in meshing engagement with the pinion
gears 98B and 98C, on a one-for-one basis. Thus, appropri-
ate rotation of the pinion gear 98A by the drive motor 90
results in raising or lowering the respective rack gears
110. And, since the supporting wall 112, is fixedly
connected to the rack gears 110, the rack gears 110 are
raised or lowered, as the case may be, in unison with one
another.
To effectuate sliding engagement of each rack gear 110
(Fig. 1) with the upright member 84 with which it is
associated, the platen module 18 includes a pair of para-
llel spaced, horizontally-extending members 114, preferably
dowels, which are fixedly connected to each of the rack
gears 110. Each of the dowels 114 extends from the rack
gear 114 to which it is connected and into the U-shaped
channel 88 of the associated upright member 84. Moreover,
the platen module 18 preferably includes a plurality of
replaceable, solid rectangularly-shaped bearing members
116, preferably made of a plastic material. The bearing
members 116 are rotatably mounted on the dowels 114 on a
one-for-one basis. The members 116 are each externally
dimensioned for sliding engagement with each of the chan-
nels 88 to permit the members 116 to be interchangeably
mounted on the dowels 114. Without departing from the
spirit and scope of the invention, the dowels 114 may be
dimensioned for disposition in sliding engagement with the
channels 88, in which instance the provision of bearing
g
2~~(:!(1~.:32
members 116 will have been obviated due to the dowels 114
acting as bearing members.
The platen module 18 (Fig. 1) further includes a
rectangularly-shaped plate 120 which is fixedly mounted on
the upper ends each of the rack gears 110 for movement
therewith. The plate 120 has opposed front and rear edges,
122 and 124 respectively, which extend lengthwise of the
plate 120, and has opposed end edges 126, which extend
transversely between the front and rear edges 122 and 124.
ZO According to the invention, the platen module 18 (Fig.
1) additionally includes a resilient platen member 130,
which is preferably made of an elastic material, such as
rubber or a rubber-like material, including but not limited
to an elastomeric material. The platen member 130 is
preferably rectangularly-shaped and has lower and upper
surfaces, 132 and 134 respectively, which are preferably
flat surfaces. Further, the platen member 130 has front
and rear edges, 136 and 138 respectively, which extend
lengthwise of the member 130, and has opposed leading and
trailing end edges, 140 and 142 respectively, which extend
transverse to and between the front and rear edges 136 and
138. In addition, the platen member 130 includes a plura-
lity of intersecting channels 144 (Fig. 2) formed therein.
The channels 144 (Fig. 2) each extend into the platen
member 130 from the lower surface 132 thereof, and prefer-
ably have an inverted U-shape transverse cross-section, as
viewed from the front edge 136 of the platen member 130
when the upper surface 134 thereof is facing upwardly. The
channels 144 preferably comprise a plurality of parallel-
spaced, transversely-extending, channels 144A which are
located at evenly spaced intervals between the opposed end
edges 140 and 142. The channels 144A intersect the platen
member's front edge 136, but not the rear edge 138, as a
result of which the front edge 136 tends to flex more
readily than the rear edge 138 when downward pressure is
exerted on the upper surface 134 of the platen member 130.
- 10 -
2~~C1~~~3~
The channels 144 also preferably comprise a pLura.Iity of
parallel-spaced, longitudinally-extending, channels 1448
which are located at evenly spaced intervals between the
front and rear edges 136 and 138. The channels 1448
intersect the platen member's leading end edge 140 and each
of the channels 144A, but do not intersect the trailing end
edge 142, as a result of which the leading end edge 140
tends to flex more readily than the trailing end edge 142
when downward pressure i.s exerted on the upper surface of
the platen member 130, As thus constructed, the platen
member 130 includes a longitudinally-extending rear portion
150, which is bounded by the rear edge 138 and a plane
extending through the rear ends of the channels 144A.
Further, the platen member 130 includes a transversely-
extending trailing end portion 152 which is bounded by the
trailing end edge 142 and a plane extending through the
trailing ends of the channels 144B. Moreover, the longitu-
dinally-extending rear portion 150, and transversely-
extending trailing end portion 152, are each less flexible
than the remainder of the platen member 130. In addition,
the platen member 130 includes an elongate, rectangularly-
shaped ledge 160 formed therein, which longitudinally
extends from the trailing end edge 142, along the front
_ edge 136 but not to the leading end edge 140. Thus, the
ledge 160 is not coextensive in length with the front edge
136. The platen module 18 additionally includes a rectan-
gularly-shaped, flat member 162 which is made of a substan-
tially inflexible metal, metallic or plastic material, and
has substantially the same dimensions as the ledge 160.
The member 162 is mounted on the ledge 160 and is suitably
fixedly attached to the platen member 130 as by means of an
adhesive substance. As thus mounted, the member 162
extends marginally along the front edge 136 of the platen
member 130, and the upper surface 164 of the member 162
lies in the same plane as the upper surface 134 of the
platen member 130. When downward pressure is exerted on
its upper surface 164 of the member 162, the downward
forces occasioned thereby are distributed along the length
and width of the member 162, and thus along a marginal
- 11 -
iCe''~~'~ l ~~~.~'Ci
portion of the platen member 130 which is coextensive in
length and width with the ledge 160.
For rapidly venting compressed air from the channels
144 (Fig. 2) when a downward force is exerted on the upper
surface 134 of the platen member 130, the platen member 130
may either include a plurality of additional channels 170
which extend into the platen member. 130 from the lower
surface 132 thereof or a plurality of apertures 172 formed
in the plate 120. Assuming the provision of additional
channels 170, the channels 170 are preferably
semi-circularly shaped in transverse cross-section, para-
llel-spaced with respect to one another and transversely-
extend into the platen member 130, from the front edge 136
thereof, at evenly spaced intervals between the opposed end
edges 140 and 142. Moreover, the channels 170 extend
parallel to the channels 144A and intersect each of the
channels 144B. Assuming the provision of the apertures
172, the apertures 172 are preferably located at the
intersections of the respective channels 144A and 144B.
According to a second embodiment of the invention, the
rack gears 110 (Figs. 1 and 2), supporting wall 112 and
plate 120 are preferably manufactured as a single piece-
part made of a molded plastic material which includes
portions corresponding to the gears 110, wall 112 and plate
120. As thus constructed the gear portions 110 depend from
the inner surface of the plate, and the strut, or wall,
portion 112 extends between the inner surfaces of the
respective gear portions 110. Moreover, the piece-part,
110, 112, 120, is preferably provided as a piece-part 110,
112, 120 of a platen assembly which also includes the
platen member 130, fixedly connected to the plate portion
120, and includes the flat member 162 fixedly connected to
and embedded in the platen member 130. Without departing
from the spirit and scope of the invention, the piece part
110, 112, 120 may additionally include as portions thereof,
the two pairs of horizantally-extending members or dowel
portions 114. In which instance the dowell portions 114
- 12 -
2~pt ~~~~..~~
would extend from the outer surfaces of the rack gear
portions 110. As thus constructed and arranged the
piece-part 110, 112, 114, 120 is preferably combined with
the platen member 130 and flat member 162 as a replaceable
platen assembly of the platen module 18. Of course, the
dowel portions 114 of the piece-part 110, 112, 114, 120 may
be either dimensioned for sliding engagement with the
upright member channels 88 (Fig. 1) or, assuming the
provision of replaceable bearing members 88, dimensioned
1~ for rotatably mounting replacement bearing members 88
thereon, as needed, when the platen assembly is slidably
connected to the remainder of the platen module 18.
In operation, a letter 46 fed to the mailing machine
is fed between the first ski member 62 and the portion
of the belt 74 which protrudes through the first deck
aperture 52. The ski member 62 urges the letter 46 into
engagement with the moving belt 74 against the force
exerted thereagainst by the spring loaded arm 58. As the
belt 74 feeds the letter 46, the letter 46 is moved down-
2~ stream on the deck 44 beneath the postage metering module
14 and into overlying relationship with the deck aperture
48. Thus the remaining ski members 62 successively engage
the upper surface of the letter 46 for urging the letter 46
into continuous engagement with the moving belt 74. When
the leading edge of the letter 46 has arrived at a
predetermined location, which, for the purposes of this
discussion may be taken to be just beyond the downstream
end of the deck aperture 48, then the first set of rollers
70, and thus the belt 74 looped thereabout, are lowered
beneath the upper surface of the deck 44, as a result of
which the belt 74 disengages the letter 46, thereby
disposing the letter in a predetermined stationary position
on the deck 44. The letter 46 is then weighed for postage
calculation purposes, and the appropriate printwheels 26
are indexed for locating the appropriate fonts 28
corresponding to the postage value into the printing
location along the line 34. At which juncture, the postage
value is ready to be printed on the letter 46. A more
- 13 -
2i.~{7()~3~
detailed description of the aforesaid operation of the
mailing machine 10 is set forth in the aforesaid U.S.
Patent Application of Abellana et al.
According to the invention, after the above-described
operation of the mailing machine 10 (Fig. 1.), the platen
t
module 18 enters into a printing cycle of operation during
which the motor 90 is conventionally energized for appro-
priately rotating the output shaft 94 to cause the drive
gear 96 to drive the gear 98A, and thus the connected shaft
100, pinion gears 98B and 98C and meshing rack gears 110.
The pinion gears, 98B and 98C, are initially appropriately
rotated to drive the rack gears 110 upwardly, thereby
raising the platen member 130 vertically upward and through
the deck aperture 48, for urging the letter 46 on the
platen member 130 into printing engagement with the print-
ing die, 28, 40. Thereafter the pinion gears, 98B and 98C
are appropriately rotated to drive the rack gears 110
downwardly, thereby lowering the platen member 130 verti-
cally downward and through the deck aperture 48, for
lowering the letter 46 out of printing engagement with the
printing die, 28, 40 and back into engagement with the deck
44. Thus, the platen member 162 is reciprocably raised and
lowered during the printing cycle. Thereafter, the trans-
porting module 22 is conventionally operated for feeding
the letter 46 downstream from beneath the postage metering
module 14 and thus away from the mailing machine 10.
In the course of the aforesaid printing cycle of
operation of the platen module 18 (Fig.1), the flat member
162, mounted on the platen member ledge 160, engages and
lifts the ski members 62 upwardly against the force exerted
thereon by the spring loaded arms 58, to prevent the ski
members 62 from holding the letter 46 down against the
force exerted on the letter 46 by the platen member 130, as
the platen member 130 resiliently urges the letter 46 into
engagement with the printing die, 28, 40. Moreover, as
shown in Fig. 3, as the letter 46 is urged into engagement
with the printing die 28, 40, and the platen member 130 is
- 14 -
;~~~c~~~~~
resiliently compressed against the letter 46, the upper
surface 134 of the member 130 deforms to accommodate
variations in thickness of the letter 46. As a result, the
upper surface 134 of the letter 46 is flattened against the
printing die, 28, 40. As the platen member 130 deforms,
air that may otherwise be trapped at the intersections of
the channels 144A and 144B, due to collapse of the walls
thereof, is vented from beneath the member 130 via the
channels 170, or via the apertures 172. In this
connection, it is noted that in practice, the speed with
which the platen member 130 is compressed, during each
printing cycle, varies from about 15 milliseconds for thick
letters 46, i.e., those having a thickness of about
three-quarters of an inch, to about 30 milliseconds for
thin letters 46, i.e., those having a thickness of about
one-sixteenth of an inch. Further, in the course of
compression of the platen member 130, since the platen
member's respective longitudinally-extending and trans-
versely-extending portions, 150 and 152 (Figs. 2), do not
include channels 144 or 170 formed therein, the forces
exerted on the letter 46 (Fig. 3) by the platen member 130,
in the vicinity of the ridges 47A and 47B, are greater than
those exerted on the letter 46 by the remainder of the
member 130, thus ensuring that the upper surface of the
letter 46 in the vicinity of the ridges, 47A and 47B, is
flattened against the printing die 28, 40. As a result,
the upper surface of the letter 46 in the vicinity of the
ridges, 47A and 47B, is marked with the same degree of
clarity as the remainder of the letter 46 is marked by the
printing die 28, 40. Moreover, the grey scale level of
printing on letters, including stepped letters and stepped
mail, having either or both types of ridges, 47A or 47B, is
substantially completely uniform.
In accordance with the objects of the invention there
has been disclosed improved printing apparatus, including
structure for enhancing the quality of printing on letters
in flat bed printing apparatus, and improved apparatus for
marking letters including structure for resiliently urging
- 15 -
~r~.~~.) ~l~..a3ilr
a letter into engagement with a printing die, as exempli-
fied by the provision of a reciprocable platen having a
resilient, channeled, member mounted thereon. Moreover,
there has been disclosed an article of manufacture which
includes a pair of rack gears, having integrally connected
thereto a platen and supporting structure extending between
the gears, in combination with a resilient platen member.
Since the implementation of other variations and
modifications of the above discussed illustration embodi
ments of the invention will be apparent to those skilled in
the art, the invention is not limited by the specific
embodiments described. Rather, the following claims should
be interpreted to cover the subject matter set forth
therein and any equivalents thereof that fall within the
true spirit and scope of the invention.
- 16 --
