U.S. patent number 3,835,771 [Application Number 05/356,393] was granted by the patent office on 1974-09-17 for print train permitting accelerated printing speeds in a line printer.
This patent grant is currently assigned to Burroughs Corporation. Invention is credited to Stephen Barasch, John W. Funk, Eugene L. Merlino, Jr., Daniel J. Woods.
United States Patent |
3,835,771 |
Funk , et al. |
September 17, 1974 |
PRINT TRAIN PERMITTING ACCELERATED PRINTING SPEEDS IN A LINE
PRINTER
Abstract
A print train of predetermined length and comprised of a
plurality of type carrying blocks is provided with an increased
number of hammer impactable type characters to thereby enable the
realization of significantly accelerated printing speeds, the type
blocks being individually and alternately driven to advance a
toothed belt to which the blocks are separately coupled around a
pair of rotatable sprockets, said accelerated printing speeds being
realized without an accompanying degradation of printing quality
resulting from the closer spacing of the adjacent characters, means
being provided to shield the characters adjacent to an impacted
character against the striking force of the hammer associated with
such impacted character.
Inventors: |
Funk; John W. (Plymouth,
MI), Merlino, Jr.; Eugene L. (Dearborn Heights, MI),
Barasch; Stephen (Westland, MI), Woods; Daniel J.
(Plymouth, MI) |
Assignee: |
Burroughs Corporation (Detroit,
MI)
|
Family
ID: |
23401277 |
Appl.
No.: |
05/356,393 |
Filed: |
May 2, 1973 |
Current U.S.
Class: |
101/111; D18/29;
101/93.14 |
Current CPC
Class: |
B41J
1/20 (20130101) |
Current International
Class: |
B41J
1/00 (20060101); B41J 1/20 (20060101); B41j
007/06 () |
Field of
Search: |
;101/93C,111,375,269,401.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Coven; Edward M.
Attorney, Agent or Firm: Uren; Edwin W. Fish; Paul W. Hall;
Charles S.
Claims
What is claimed is:
1. An improved rotatably supported print train operatively
associated with a plurality of linearly arranged selectively
impactable hammers in a printing device and responsive to driving
means of said printing device to bring selected type characters
into printing position relative to said hammers for producing
printed characters on printable media of varying rigidity, said
print train comprising:
a. an endless toothed belt encompassing a pair of spaced-apart
sprockets providing said rotatable support for said print
train,
b. a predetermined plurality of type carrying blocks distributed
along and removably coupled to said endless belt in engaged
relationship relative to the teeth thereof, each of said blocks
having a plurality of external teeth disposed on an edge thereof
and in cooperable relationship relative to said driving means to be
intermittently advanced thereby so as to rotate said belt around
said sprockets, a type lug presenting a type carrying surface
contiguous to and normally disposed of said external teeth, and a
plurality of spaced-apart type characters arranged along said type
carrying surface in close proximity to one another and effective
for producing said printed characters on said printable media of
said varying rigidity upon the impacting of selected hammers
thereagainst, and
c. media supporting means fixed to said type carrying surfaces of
said type lugs and effective for preventing the printing of ghost
characters on printable media of relatively greater rigidity such
as would result from said close proximity of said type characters
on said type carrying surfaces, said media supporting means
comprising an elongated barrier fixed to and transversely disposed
of said type carrying surface of each of said type lugs
intermediate adjacent pairs of said type characters thereof, each
of said barriers extending outwardly from the type lug to which it
is fixed by a distance substantially equal to the extension of said
adjacent type characters therefrom, whereby said printable media is
held away from the type characters oppositely adjacent to a
selected type character when activated into printable contact with
said selected character upon impacting of the hammer associated
therewith.
2. An improved printing mechanism for producing printed characters
on printable media of varying rigidity comprising:
a. a media guideway,
b. means for advancing said media along said guideway,
c. a plurality of selectively impactable hammers transversely
disposed on one side of said media guideway,
d. a rotatably supported endless print train associated with
driving means of said printing mechanism and transversely and
normally disposed relative to said media guideway on the opposite
side thereof from said plurality of hammers, said print train
having a predetermined plurality of type character carrying blocks
arranged therealong such that the rotation of said print train by
said driving means is effective to transport said blocks as between
an operative position thereof contiguous to said guideway and said
hammers and an inoperative position thereof remote from said
guideway and said hammers, each of said blocks including a
plurality of external teeth disposed along an edge thereof and in
cooperable relationship relative to said driving means to be
intermittently advanced thereby so as to rotate said print train
around said rotatable support thereof, a type lug presenting a type
character carrying surface contiguous to and normally disposed of
said external teeth, a plurality of spaced-apart type characters
arranged along said type character carrying surface in close
proximity to one another and effective for producing said printed
characters on said printable media of said varying rigidity upon
the impacting of selected hammers thereagainst, and
e. media supporting means fixed to said type character carrying
surfaces of said type lugs and effective for preventing the
printing of ghost characters on printable media of relatively
greater rigidity such as would result from said close proximity of
said type characters on said type carrying surfaces, said media
supporting means comprising an elongated barrier fixed to and
transversely disposed of said type character carrying surface of
each of said type lugs intermediate adjacent pairs of said type
characters thereof, each of said barriers extending outwardly from
the type lug to which it is fixed by a distance substantially equal
to the extension of said adjacent type characters therefrom,
whereby said media is held away from the type characters oppositely
adjacent to a selected type character when activated into printable
contact with said selected character upon impacting of the hammer
associated therewith.
3. An improved type character carrying block for use in a
predetermined plurality in an endless rotatably mounted print train
in a printing device for producing printed characters on printable
media of varying rigidity, said print train having an endless
toothed belt disposed in encompassing relationship with a pair of
spaced-apart rotatable sprockets, said belt being effective for
removably coupling said predetermined plurality of type character
carrying blocks thereto relative to the teeth thereof, said
printing device having media guiding and advancing means, a
predetermined plurality of impactable hammers transversely arranged
relative to the direction of advancement of the media, and print
train driving means effective for rotating said belt and said
blocks to thereby advance selected type characters into printable
relationship with said hammers, said improved type carrying block
comprising:
a. a plurality of external teeth disposed along an edge thereof and
in cooperable relationship relative to said driving means to be
intermittently advanced thereby so as to rotate said belt around
said pair of sprockets,
b. a type lug presenting a type character carrying surface
contiguous to and normally disposed of said external teeth,
c. a plurality of spaced-apart type characters arranged along said
type character carrying surface in close proximity to one another
and effective for producing said printed characters on said
printable media of said varying rigidity upon the impacting of
selected hammers thereagainst, and
d. media supporting means fixed to said type character carrying
surface of said type lug and effective for preventing the printing
of ghost characters on printable media of relatively greater
rigidity such as would result from said close proximity of said
characters on said type character carrying surface, said media
supporting means comprising an elongated barrier fixed to and
transversely disposed of said type character carrying surface of
said type lug intermediate adjacent pairs of said type characters
thereof, each of said barriers extending outwardly from the type
lug by a distance substantially equal to the extension of said
adjacent type characters therefrom, whereby said printable media is
held away front the type characters oppositely adjacent to a
selected type character when activated into printable contact with
said selected character upon impacting of the hammer associated
therewith.
4. An improved type carrying block for multiple use in association
with a rotatably mounted and driven endless internally toothed belt
to define a print train of a printing device having selectively
impactable hammers, said printing device being effective for
producing printed characters on printable media of varying
rigidity, said block comprising:
a. an apertured belt receiving member presenting a flat orthogonal
surface for receiving the outside surface of said belt, said member
additionally presenting, within the framework of the aperture
thereof, a plurality of oppositely disposed offset and inwardly
directed projections, said projections being effective for
clampably receiving the inside surface of said belt and
particularly for engageably receiving recesses formed by said
internal teeth thereof,
b. a plurality of external teeth substantially disposed in coplanar
relationship with said belt receiving member, said external teeth
being responsively effective for driving said belt and said print
train,
c. an elongated type lug parallelly disposed relative to said belt
receiving member and normally disposed relative to said external
teeth, said type lug presenting a type character carrying surface
having a plurality of spaced-apart type characters integrally
formed thereon in close proximity to one another, said type
characters being effective for producing said printed characters on
said printable media of said varying rigidity upon the impacting of
selected hammers thereagainst, said type character carrying surface
having also a plurality of elongated media supporting barriers
transversely disposed relative thereto and intermediate adjacent
pairs of said type characters, said barriers being effective for
preventing the printing of ghost characters on printable media of
relatively greater rigidity such as would result from said close
proximity of said type characters on said type character carrying
surface, each of said barriers extending outwardly from the type
lug by a distance substantially equal to the extension of said
adjacent type characters therefrom, whereby said printable media is
held away from the type characters oppositely adjacent to a
selected type character when activated into printable contact with
said selected character upon impacting of the hammer associated
therewith.
Description
BACKGROUND OF THE INVENTION
Train printers of the type produced by Burroughs Corporation under
style number B9247, and partially disclosed in U.S. Pat. No.
3,577,913 issued on May 11, 1971 to Herbert J. Hinze, may be
characterized by the combination of a predetermined number of type
characters on individual type carrying blocks, the blocks being
removably couplable to an internally toothed belt to form a print
train which is rotatably supported by a pair of spaced apart
rotatable sprockets, the belt-coupled blocks not being otherwise
interconnected. In train printers of this kind, rotation of the
print train is accomplished by driving means cooperating
alternately with coupling means disposed on the individual blocks,
the alternate driving of the individual blocks serving to rotate
the toothed belt around the rotatable sprockets and to abuttably
push the downstream blocks in the direction of the sprockets, the
blocks being separated from their abuttable relationship as they
are pulled by the internal teeth of the belt around the peripheries
of the sprockets. Train printers of this general character provide
advantages over prior art chain printers wherein the individual
type characters are fixed to a belt or band, the band being rotated
by driving means which cooperates directly with at least one of the
sprockets, the direct attachment of the type characters to the band
and the direct driving of the band by cooperable driving means
having been found to present various cost disadvantages in the
areas of design and maintenance, and to present various operational
disadvantages in the areas of type wear and band distortion.
A brief description of the construction and operation of the print
train described in detail in the above-referenced patent is
hereinafter presented with reference to FIGS. 1 through 5. As shown
in FIGS. 1 and 5, an endless belt 3 having internal teeth 5 is
rotatably supported by a pair of rotatable and uprightly disposed
sprockets 7 and 9, the lowermost portion of the belt representing
an operative printing position thereof, and the uppermost portion
representing an inoperative position, rotation fo the belt by
hereinafter described means serving to advance the belt and
particular areas thereof as between the operative and inoperative
positions. A predetermined number of type carrying blocks 11, shown
in detached form in FIG. 2, and in coupled relationship with the
belt 3 in FIGS. 1 and 5, are each comprised of an apertured belt
receiving member 13 for receiving the outside surface of the belt
3, and a plurality of offset and inwardly directed projections 15
for clampably receiving the inside surface of the belt and
particularly the recesses formed by the internal teeth 5 thereof.
Each of the type carrying blocks 11 is additionally comprised of a
plurality of external teeth 17 extending outwardly from the belt
receiving member 13, and an elongated type lug 19 normally disposed
of the external teeth 17 and the belt receiving member 13, the type
lug 19 presenting a type character carrying surface 21 having a
plurality of type characters 23 integrally formed thereon, the type
lug 19 assuming a downwardly directed position when the block 11 is
assembled on the belt 3 and is located in the operative position of
the belt, as shown in FIG. 1. Each of the blocks 11 is also
provided with spacing pads 25 disposed on opposite sides of the
type lug 19, the function thereof being to abuttably advance the
downstream blocks to the sprocket 7, and from the sprocket 7 to the
sprocket 9 when a given block 11 is drivably advanced by
hereinafter described means. The type carrying blocks 11 are
assembled on the belt 3 as illustrated in FIG. 3, it being noted
from FIG. 3 that the belt is wider than the sprockets 7 and 9, and
that the offset and inwardly directed projections 15 of the blocks
engage opposite portions of the belt which extend outwardly from
the sprockets (as identified at 27 in FIG. 3), each block being
coupled to the belt 3 with minimal linear play as permitted by the
relative dimensions of the recesses between the teeth 5 of the belt
and the projections 15 of the blocks.
With the plurality of type carrying blocks 11 coupled to the belt
3, the print train so formed is continuously rotatable about the
sprockets 7 and 9 to thereby bring selected type characters 23 into
impact-receiving relationship with a plurality of linearly arranged
column-identifying hammers 29, the print train being rotated in a
counterclockwise direction (as viewed in FIG. 1) through the
driving cooperation of a drive gear 31 fixed to a drive shaft 33
(as best illustrated in FIG. 4). Rotation of the drive gear 31 and
the peripheral teeth 35 thereof is effective to alternately engage
the external teeth 17 of the type carrying blocks 11 to thereby
alternately advance each block 11 in the direction of the
downstream sprocket 7, the blocks 11 located between the driven
block and the sprocket 7 being abuttably pushed to the sprocket
through contact of the spacing pads 25 of the various blocks,
movement of the driven blocks being transmitted to the belt by
means of the hereinbefore described engagement of the projections
15 with the overhanging toothed portions 27 of the belt. Engagement
of the drive gear 31 with the external teeth 17 of the individual
blocks 11, and the pushing effect of the driven blocks on the
downstream blocks can best be understood with reference to FIG. 4.
FIG. 5 is illustrative of the manner in which the movement of the
belt 3 serves to pull the blocks 11 around the sprockets 7 and 9,
it being noted that the abutting relationship between the blocks is
removed during such circular movement. It can be seen from FIG. 5
that the leading edges of the projections 15 of the blocks 11 that
are being moved in the direction of the sprockets 7 and 9 are in
contact with the trailing edges of the edges of the internal teeth
5 of the belt 3, the movement of such blocks serving to transmit
rotational motion to the belt 3, whereas the trailing edges of the
projections 15 of the blocks being moved around the sprockets 7 and
9 are in contacting relationship with the leading edges of the
internal teeth 5, the moving belt 3 accordingly serving to pull the
blocks 11 around the sprockets.
Known train printers of the type produced by Burroughs Corporation
under style number B9247 have commonly provided 120 or 132 linearly
arranged impactable hammers 29, and 48 type carrying blocks 11
disposed along the print train, each of the blocks 11 being
provided with four type characters 23, as shown in FIG. 2,
presenting a total of 192 selectable type characters arranged along
the belt 3. With a print train rotating speed of 170.66 inches per
second, a printing throughput of from 440 to 1,200 lines per minute
has been achieved, depending upon the character set employed, a 750
lines per minute throughput being achieved with a 48 character set,
and with proportionately higher and lower throughput speeds with
smaller and larger character sets, respectively. As is well known
in the line printer art, increased printing throughput may be
achieved with a given character set by increasing the total number
of type characters disposed along the print train, or
alternatively, through the employment of smaller character sets
that permit increased repetition of the individual characters
comprising the set.
With the increased processing speeds of present generation
computers, continued attention is given to the development of ways
and means of increasing the throughput speeds of input and output
peripherals comprising data processing systems, and particularly to
ways and means of increasing the throughput speeds of line
printers. Since the employment of smaller character sets would
present serious limitations to printing flexibility, attention has
been focused on ways and means of increasing the total number of
characters along the print train, as by increasing the number of
type characters per block from 4 to 6, the total number of
characters provided by the 48 type blocks being thus increased from
192 to 288. Early experimentation with this approach, in an effort
to achieve a printing throughput of 1,000 lines per minute with a
48 character set, resulted in the "ghost" printing of type
characters adjacent to the characters that were impacted by the
hammers 29, as illustrated in FIG. 6 wherein the printed characters
37 on the media are accompanied by ghost characters 39.
Investigation into the cause of such ghost printing revealed a
tendency of a hammer 29 (FIG. 1), when impacted against a selected
type carrier 23, to advance the media into light printing contact
with the type characters adjacent to the selected character, the
tendency being aggravated proportionally to an increase in the
stiffness of the media and to a reduction in the space between the
type characters on the blocks 11.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to
significantly increase the printing throughput of train printers of
the above characterized type, as from 750 lines per minute to 1,050
lines per minute in the case of the Burroughs train printer, such
increase in speed to be achieved with a 48 character set.
It is a further object of the present invention to achieve this
significant increase in printing throughput without altering the
over-all dimensions of the printer, and without changing the number
and size of the type carrying blocks that are disposed along the
print train thereof.
It is yet a further important object of the present invention to
provide for such significant increase in printing throughput
without degrading the quality of the printed result, as by the
entertainment of ghost printing of the kind illustrated in
exaggerated form in FIG. 6.
Yet another object of the present invention is to provide a print
train wherein the pitch distance between the type characters is
significantly decreased, and wherein each type carrying block is
provided with means effective for preventing a printing contact as
between the media and the type characters adjacent a selected type
character when the selected type character is impacted by its
associated hammer.
BRIEF DESCRIPTION OF THE DRAWING
The drawing figures accompanying the present specification,
hereinafter described, are presented as an aid to understanding the
general character of train printers, to comprehending the nature of
the problem that is customarily encountered in attempting to
achieve significantly increased throughput speeds therewith, and to
conveying a lucid explanation of the solution to the problem as
contemplated by the inventors.
FIG. 1 is a rear elevational view of a print train employed in line
printers of the train type;
FIG. 2 is a front view of a type carrying block of the kind
comprising the print train of FIG. 1, such block being provided
with the conventional number of four type characters disposed on a
type carrying surface thereof;
FIG. 3 is a sectional view of a type carrying block assembled on
the belt and in engaged relationship with one of the sprockets;
FIG. 4 is a bottom view of the mechanism of FIG. 1;
FIG. 5 is a partial sectional view of the print train of FIG. 1 in
association with one of the sprockets;
FIG. 6 is an enlarged and exaggerated sample of a printed result
showing the ghost printing of characters on the media intermediate
the intended printed characters;
FIG. 7 is an enlarged sample of the desired printed result on the
media;
FIG. 8 is a front view of the inventive type carrying block showing
six type characters arranged along the type carrying surface
thereof and with barriers interposed between the characters;
and
FIG. 9 is a perspective view of the type carrying surface of the
inventive block of FIG. 8, showing the six type characters with
barriers interposed therebetween.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The objective of increasing the printing throughput of the above
referenced train printer from 750 to 1,050 lines per minute, based
on a 48 character set, without altering the dimensions of the print
train or the number or size of the type carrying blocks 11 carried
by the belt 3, led to the development of the type carrying block
11' shown in FIG. 8, 48 of such blocks being arranged along the
belt 3 with each block containing a total of six type characters
23, the type characters accordingly being spaced in closer
proximity to one another. The effect of this increase of two type
characters per block resulted in an increase in the total number of
type characters in the print train from 192 to 288, such increased
number of type characters permitting a multiplied repetition
thereof along the belt 3 to thereby provide the desired increase in
printing throughput. With the resultant decreased spacing between
the type characters on the individual blocks 11', the inventive
blocks were additionally provided with barriers 41 disposed between
the type characters 23, such barriers, being of substantially equal
height to the height of the type characters 23 extendiing outwardly
from the type lugs 19, serving to support the media upon impacting
of a hammer 29 against a selected type character 23 to thereby
prevent the media from being moved into printable contact with the
type character adjacent the selected character. The barriers 41 may
present a substantially flat raised surface between the type
characters as illustrated in FIG. 9, or provided with a slightly
radiused raised surface depending upon the relative stiffness of
the media to be used and the corresponding adjacent characters.
* * * * *