U.S. patent number 3,625,142 [Application Number 05/045,008] was granted by the patent office on 1971-12-07 for high-speed printing apparatus having slidably mounted character-forming elements forming a dot matrix.
This patent grant is currently assigned to Datascript Terminal Equipment Corp.. Invention is credited to Aaron D. Bresler.
United States Patent |
3,625,142 |
Bresler |
December 7, 1971 |
HIGH-SPEED PRINTING APPARATUS HAVING SLIDABLY MOUNTED
CHARACTER-FORMING ELEMENTS FORMING A DOT MATRIX
Abstract
A high-speed printer apparatus characterized by a font assembly
having a plurality of slidably mounted character-forming elements
forming a dot matrix. The dot projections are so arranged on said
elements that any given character may be formed on said matrix at
any given character position by small linear relative movements of
such elements. Hammer means are mounted opposite the font assembly
and are movable to said character positions and actuated to press
the character image onto the paper by means of a ribbon. Logic
means are provided to control the position of the character-forming
elements and hammer means and the sequence of operation, all in
response to data input signals.
Inventors: |
Bresler; Aaron D. (Merrick,
NY) |
Assignee: |
Datascript Terminal Equipment
Corp. (Lindenhurst, NY)
|
Family
ID: |
21935511 |
Appl.
No.: |
05/045,008 |
Filed: |
June 10, 1970 |
Current U.S.
Class: |
101/93.04;
178/30; 346/78; 400/104; 400/124.29; D18/29 |
Current CPC
Class: |
B41J
2/31 (20130101) |
Current International
Class: |
B41J
2/22 (20060101); B41J 2/31 (20060101); B41j
001/16 () |
Field of
Search: |
;101/93C,93R,109
;197/1,17,1.5,1.6 ;346/50,78 ;178/30 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Penn; William B.
Claims
I claim:
1. A font assembly for a high-speed printer apparatus for forming
characters from a dot matrix, comprising a housing, a plurality of
character-forming elements mounted in said housing and each having
a series of dot print positions extending along their lengths, said
dot print positions each characterized by a dot pattern and some of
said dot print positions having a different dot pattern from some
of the others of said dot print positions, said elements being
arranged to form a dot matrix, means for moving said elements
relative to each other along their lengths so as to align at least
some of said dot print positions on each of said elements in a
direction generally perpendicular to the lengths of said elements,
whereby at least a portion of said dot matrix is effective to
display a particular character made up of dot projections.
2. The font assembly of claim 1, wherein said character-forming
elements comprise thin, elongated members extending in a first
direction and stacked in a second direction generally perpendicular
to said first direction and having said dot print positions
extending in said first direction on aligned end surfaces thereof,
said members being slidable relative to each other in said first
direction.
3. The font assembly of claim 2, further comprising bearing means
disposed between said stacked members for facilitating the sliding
engagement thereof.
4. The font assembly of claim 3, wherein said bearing means
comprises wire means mounted on said housing and said members are
provided with groove means extending in said first direction and
adapted to operatively slidingly engage said wire means, whereby
said members are guided along said wire means in said first
direction.
5. The font assembly of claim 1, further comprising hammer means
disposed opposite said dot print positions on said
character-forming elements, means for feeding paper between said
character-forming elements and said hammer means, ribbon means
between said hammer means and said elements adjacent said paper,
and impact means for actuating said hammer means to press said
ribbon means and said paper against said dot matrix formed by said
character-forming elements.
6. The font assembly of claim 5, wherein said character-forming
elements comprise thin, elongated members extending in a first
direction and stacked in a second direction generally perpendicular
to said first direction and having said dot print positions
extending in said first direction on aligned end surfaces thereof,
said members being slidable relative to each other in said first
direction.
7. The font assembly of claim 6, further comprising bearing means
disposed between said stacked members for facilitating the sliding
engagement thereof.
8. The font assembly of claim 7, wherein said bearing means
comprises wire means mounted on said housing and said members are
provided with groove means extending in said first direction and
adapted to operatively slidingly engage said wire means, whereby
said members are guided along said wire means in said first
direction.
9. The font assembly of claim 5, further comprising means to move
said hammer means along the lengths of said character-forming
elements.
10. The font assembly of claim 6, further comprising means to move
said hammer means in said first direction.
11. The font assembly of claim 7, further comprising means to move
said hammer means in said first direction.
12. The font assembly of claim 8, further comprising means to move
said hammer means in said first direction.
13. The font assembly of claim 9, wherein said hammer means
comprises a plurality of hammers spaced along the lengths of said
character-forming elements.
14. The font assembly of claim 10, wherein said hammer means
comprises a plurality of hammers spaced along said first
direction.
15. The font assembly of claim 11, wherein said hammer means
comprises a plurality of hammers spaced along said first
direction.
16. The font assembly of claim 12, wherein said hammer means
comprises a plurality of hammers spaced along said first
direction.
17. The font assembly of claim 1, wherein said means for moving
said character-forming elements comprises magnetically actuated
linear translation means.
18. The font assembly of claim 17, wherein said character-forming
elements comprise thin, elongated members extending in a first
direction and stacked in a second direction generally perpendicular
to said first direction and having said dot print positions
extending in said first direction on aligned end surfaces thereof,
said members being slidable relative to each other in said first
direction.
19. The font assembly of claim 18, further comprising bearing means
disposed between said stacked members for facilitating the sliding
engagement thereof.
20. The font assembly of claim 19, wherein said bearing means
comprises wire means mounted on said housing and said members are
provided with groove means extending in said first direction and
adapted to operatively slidingly engage said wire means, whereby
said members are guided along said wire means in said first
direction.
21. The font assembly of claim 17, further comprising hammer means
disposed opposite said dot print positions on said
character-forming elements, means for feeding paper between said
elements and said hammer means, ribbon means between said hammer
means and said element adjacent said paper, and impact means for
actuating said hammer means to press said ribbon means and said
paper against said dot matrix formed by said character-forming
elements.
22. The font assembly of claim 20, further comprising hammer means
disposed opposite said dot print positions on said
character-forming elements, means for feeding paper between said
elements and said hammer means, ribbon means between said hammer
means and said elements adjacent said paper, and impact means for
actuating said hammer means to press said ribbon means and said
paper against said dot matrix formed by said character-forming
elements.
23. The font assembly of claim 13, wherein said means for moving
said hammer means comprises magnetically actuated linear
translation means.
24. The font assembly of claim 16, wherein said means for moving
said hammer means in said first direction comprises magnetically
actuated linear translation means.
25. The font assembly of claim 1, wherein said character-forming
elements are adapted to be moved with respect to said housing along
their lengths in increments corresponding to one dot print position
and multiples thereof.
26. The font assembly of claim 17, wherein said character-forming
elements are adapted to be moved with respect to said housing along
their lengths in increments corresponding to one dot print position
and multiples thereof.
27. The font assembly of claim 1, wherein the arrangement of said
series of dot projections on each character-forming element is
cyclic.
28. The font assembly of claim 27, wherein one cycle of dot
projections comprises 63 discrete dot print positions.
29. The font assembly of claim 27, wherein one cycle of dot
projections comprises 98 discrete dot print positions.
30. The font assembly of claim 1, wherein said character-forming
elements are adapted to be moved along their lengths in increments
corresponding to said effective portion of said dot matrix and
multiples thereof.
31. The font assembly of claim 17, wherein said character-forming
elements are adapted to be moved in said first direction in
increments corresponding to said effective portion of said dot
matrix and multiples thereof.
32. The font assembly of claim 30, wherein said effective portion
of said dot matrix extends 7 dot print positions.
33. The font assembly of claim 31, wherein said effective portion
of said dot matrix extends 7 dot print positions.
34. The font assembly of claim 32, wherein said first and last dot
print positions of said effective portion of said dot matrix are
blanked.
35. The font assembly of claim 33, wherein said first and last dot
print positions of said effective portion of said dot matrix are
blanked.
36. The font assembly of claim 9, wherein the particular character
to be formed and its position in relation to said housing is
determined by an input signal, and further comprising font assembly
command logic means responsive to said input signal for commanding
the position of each of said character-forming elements,
character-forming element position-monitoring means for monitoring
the current position of each of said character-forming elements,
and character-forming element control logic means operatively
connected to said font assembly command logic means and said
character-forming element position-monitoring means for comparing
the current position of said character-forming elements with the
commanded position thereof and actuating said means for moving said
character-forming elements to move said elements to the commanded
position.
37. The font assembly of claim 36, further comprising hammer
position monitoring means for monitoring the position of said
hammer means, hammer control logic means responsive to said input
signal and said hammer-monitoring means for comparing the position
of said hammer means with the position of said particular character
and actuating said means for moving said hammer means to position
said hammer means in alignment with said particular character on
said dot matrix.
38. The font assembly of claim 37, further comprising sequence
command logic means responsive to said input signal, said
character-forming element-monitoring means and said
hammer-monitoring means, for controlling the sequence of hammer
actuation, character-forming element movement, and hammer
movement.
39. The font assembly of claim 38, wherein said sequence command
logic means also controls the sequence of paper feed.
40. The font assembly of claim 4, wherein said wire means comprises
a plurality of wires suspended at their ends from said housing and
said groove means comprises a plurality of grooves provided in both
surfaces of said thin members and adapted to receive said plurality
of wires respectively, an individual wire engaging the grooves of
each of two adjacent members, thereby to adapt said members to
slide relative to each other along said wires only in said first
direction.
41. The font assembly of claim 20, wherein said wire means
comprises a plurality of wires suspended at their ends from said
housing and said groove means comprises a plurality of grooves
provided in both surfaces of said thin members and adapted to
receive said plurality of wires respectively, an individual wire
engaging the grooves of each of two adjacent members, thereby to
adapt said members to slide relative to each other along said wires
only in said first direction.
42. The font assembly of claim 6, wherein said hammer means
comprises a plurality of hammers, each said hammer movable in said
first direction from a starting position along a given portion of
the length of said elements, said given portions being contiguous
to one another, and means for moving said hammers back to their
starting positions upon spanning said given portion, whereby one of
said hammers is returned to its starting position while another
hammer begins moving along its portion of the length of said
character-forming elements.
43. The font assembly of claim 9, wherein said hammer means
comprises a plurality of hammers, each said hammer movable in said
first direction from a starting position along a given portion of
the length of said elements, said given portions being contiguous
to one another, and means for moving said hammers back to their
starting positions upon spanning said given portion, whereby one of
said hammers is returned to its starting position while another
hammer begins moving along its portion of the length of said
character-forming elements.
44. The font assembly of claim 10, wherein said hammer means
comprises a plurality of hammers, each said hammer movable in said
first direction from a starting position along a given portion of
the length of said elements, said given portions being contiguous
to one another, and means for moving said hammers back to their
starting positions upon spanning said given portion, whereby one of
said hammers is returned to its starting position while another
hammer begins moving along its portion of the length of said
character-forming elements.
45. The font assembly of claim 11, wherein said hammer means
comprises a plurality of hammers, each said hammer movable in said
first direction from a starting position along a given portion of
the length of said elements, said given portions being contiguous
to one another, and means for moving said hammers back to their
starting positions upon spanning said given portion, whereby one of
said hammers is returned to its starting position while another
hammer begins moving along its portion of the length of said
character-forming elements.
46. The font assembly of claim 12, wherein said hammer means
comprises a plurality of hammers, each said hammer movable in said
first direction from a starting position along a given portion of
the length of said elements, said given portions being contiguous
to one another, and means for moving said hammers back to their
starting positions upon spanning said given portion, whereby one of
said hammers is returned to its starting position while another
hammer begins moving along its portion of the length of said
character-forming elements.
47. The font assembly of claim 1, wherein the particular character
to be formed and its position in relation to said housing is
determined by an input signal, and further comprising font assembly
command logic means responsive to said input signal for commanding
the position of each of said character-forming elements,
character-forming element position-monitoring means for monitoring
the current position of each of said character-forming elements,
and character-forming element control logic means operatively
connected to said font assembly command logic means and said
character-forming element position-monitoring means for comparing
the current position of said character-forming elements with the
commanded position thereof and actuating said means for moving said
character-forming elements to move said elements to the commanded
position.
Description
The present invention relates to high-speed printing apparatus, and
particularly to such apparatus designed for use with high-speed
data-processing equipment.
Known data printout mechanisms are of several types. The most
common and oldest type utilizes a font assembly comprising
individual elements each having a typeface corresponding to the
desired character to be printed. Means are provided for positioning
a given element opposite the space on the paper and impressing an
image by means of an inked ribbon or the like on the paper by
impact with the typeface of said element. This system is used in
most high-speed typewriter readouts.
With the advent of high-speed data processing, it became obvious
that the speed limitations on such apparatus would be determined by
the available rate of data printout. Accordingly, mechanisms have
been designed to increase the speed of positioning and actuation of
single typeface elements of the foregoing type.
Data-processing equipment has now advanced to the point where such
single typeface printout systems are no longer capable of operating
at the speeds at which output data is produced. Accordingly, new
methods have been devised to further increase the speed of data
printout. One of these methods involves the use of so-called
built-up characters, that is, the font assembly consists of a
plurality of character-building elements and a particular character
is formed on the sheet by moving said elements to a
character-forming position either sequentially or simultaneously.
These mechanisms have in the past been rather unsatisfactory due to
their complexity of operation. In addition, such mechanisms are
actuated by assemblies, such as complicated gearing and the like,
which are space consuming, prone to failure, and expensive to
manufacture and maintain.
Recently, in order to minimize the mechanical movement involved in
data printout systems, alternate nonmechanical printing methods
such as electrostatic or thermal printing and the like have been
incorporated in such systems. Again, however, the expense of these
mechanisms has proved prohibitive. Moreover, such mechanisms
usually require the use of expensive paper and are unable to
produce simultaneous multiple copies.
Accordingly, it is a primary object of the present invention to
provide a high-speed printing apparatus which is simple in
operation, inexpensive to manufacture and maintain and does not
require the use of special paper.
More particularly, it is an object of the present invention to
provide a high-speed printer of the built-up character type
utilizing a novel dot matrix font assembly to provide simplicity
and high speed of operation.
It is a still further object of the present invention to design a
font assembly for a high-speed printing apparatus wherein the
required movement of the character-forming elements is
significantly reduced to provide higher speeds of operation.
It is still another object of the present invention to design a
font assembly of the type described which may be housed in an
extremely small space and which utilizes short high-speed movements
to form any one of a variety of characters to be printed.
It is still another object of the present invention to provide a
high-speed printing apparatus of the type described in which the
character-forming elements and hammer means may be quickly and
accurately moved to the desired character print position, the
hammer actuated and the paper fed, all under the control of a
high-speed logic means receiving an input command signal.
To these ends the apparatus of the present invention comprises a
series of elongated character-forming elements each having a series
of dot projections on their operative printing surfaces arranged to
form a dot matrix. The character-forming elements are mounted for
slidable movement relative to each other and the arrangement of dot
projections thereon is such that only a small linear movement of
each element is necessary in order to realign said dot projections
from a first matrix forming a given character at a given character
print position to a second matrix forming the same or a different
character at another character print position.
A hammer assembly comprises one or more hammers each movable a
given number of character print positions and means to actuate said
hammers to impact on a sheet of paper and ribbon means disposed
between the font assembly and the hammer assembly. Logic means are
provided for commanding the position of the character-forming
elements and the hammers and controlling the sequence of movements
thereof and of the paper and ribbon feed.
To the accomplishment of the above and to such other objects as may
hereinafter appear, the present invention relates to a high-speed
printing apparatus and font assembly therefor as defined in the
appended claims and as described in this specification taken
together with the accompanying drawings in which:
FIG. 1 is a perspective view of a high-speed printing apparatus in
accordance with this invention;
FIG. 2 is a schematic illustration of a fragment of the operative
surfaces of the character-forming elements of one embodiment of the
font assembly of the present invention showing a dot matrix made up
of one cycle of dot projections on each element;
FIG. 3 is a schematic view showing a portion of the dot matrix of
FIG. 2, the character-forming elements having been moved to a
position forming the character "F;"
FIG. 4 is a schematic illustration of the operative surfaces of the
character-forming elements of a second embodiment of the font
assembly of the present invention showing a dot matrix made up of
one cycle of dot projections on each element;
FIG. 5 is a schematic view showing a portion of the dot matrix of
FIG. 4, the character-forming elements having been moved to a
position forming the character "F;"
FIG. 6 is a fragmentary perspective view, greatly enlarged, showing
the individual dot projections on the character-forming
elements;
FIG. 7 is a cross-sectional view taken generally along the line
7--7 of FIG. 1, showing the font assembly and hammer assembly with
their associated actuating mechanisms, with the hammer in its
cocked position;
FIG. 8 is a cross-sectional view similar to FIG. 7, showing the
hammer in its impact position;
FIG. 9 is a cross-sectional view taken along the line 9--9 of FIG.
7 and showing the slidable hammer mounting;
FIG. 10 is a cross-sectional view taken along the line 10--10 of
FIG. 7 showing the relative positions of the actuating mechanisms
for the character-forming elements;
FIG. 11 is a plan view, partly in section, taken along the line
11--11 of FIG. 10;
FIG. 12 is an enlarged cross-sectional view taken along the line
12--12 of FIG. 11 and showing the support wires along which the
character-forming elements are adapted to ride;
FIG. 13 is a schematic block diagram illustrating the logic means
for controlling the position of the various elements and the
sequence of operation.
FIG. 14 illustrates the 64 characters adapted to be printed by the
apparatus of the present invention.
As best shown in FIG. 1, the high-speed printing apparatus of the
present invention consists of a font assembly generally designated
10 and a hammer assembly generally designated 12. Paper 14 is fed
through the apparatus between font assembly 10 and hammer assembly
12 by means of a sprocket feed mechanism comprising a roller 16
mounted on a shaft 18 rotatably driven by suitable means (not
shown). The paper drive means is, of course, programmed to feed
paper intermittently in increments corresponding to one or more
character print lines. Roller 16 is provided with sprockets 20 at
either end adapted to be received in mating holes 21 at the outer
edges of paper 14. Suitable means may be provided on the underside
of the apparatus for receiving and processing the printed paper.
For example, the paper may be initially folded and allowed to
refold on the underside of the apparatus along the existing fold
lines in a neat pile in a receptacle provided for that purpose.
Moreover, the paper may be perforated into segments along lines
perpendicular to the feed direction and the apparatus
correspondingly programmed to print one cycle or segment of data on
each segment of paper, the printed paper being subsequently
separated into individual data sheets. The method of programming
the apparatus in this manner will become more apparent in
connection with the control logic means to be described
hereinafter. An inked ribbon 15 is intermittently fed between the
paper 14 and the hammer assembly 12 under the control of the same
logic means.
The entire arrangement shown in FIG. 1 is, of course, mounted on a
suitable frame (not shown).
The font assembly of the present invention comprises a plurality of
character-forming elements 22 mounted in a suitable housing 24. As
best shown in FIG. 1, character-forming elements 22 are in the form
of thin metal strips or tapes mounted in stacked relation and
having their operative print surfaces aligned and extending out
from a slot 26 in housing 24.
As best seen in FIG. 2, the operative print surfaces of each tape
22 comprises a series of dot print positions along its lengthwise
edge. Each dot print position is characterized by the presence or
absence of a dot projection 32, two of such dot projections being
shown in FIG. 6. As seen there, dot projections 32 are in the form
of discrete squares jutting out from the edge of tape 22 and having
their edges slightly chamfered at 33.
The operative print surfaces of tapes 22 cooperate to form a dot
matrix, adapted upon relative movement of said tapes to form any
one of a plurality of characters at any one of a number of
character print positions along the length of housing 24.
For this purpose, tapes 22 are mounted in slidable relationship
within slot 26 in housing 24. As best shown in FIGS. 11 and 12,
each tape 22 is provided with grooves 28 in its top and bottom
surfaces adapted to receive support wires 30 which are suspended at
either end on housing 24 within slot 26. Each wire is disposed
between two adjacent tapes and is seated in matching grooves 28 on
the top and bottom surfaces thereof respectively. As best shown in
FIG. 12, grooves 28 are formed in the shape of a circular arc
slightly shallower than a semicircle so that wires 30 (having a
circular cross section) serve to separate the surfaces of adjacent
tapes. Wires 30 and grooves 28 preferably are each coated with a
low-friction material 31 such as Teflon or the like. Thus wires 30
function as both support bearings and guide wires along which tapes
22 are adapted to slide within slot 26 in housing 24. As seen in
FIG. 1, slot 26 is somewhat longer than tapes 22 to accommodate
such slidable movement.
It will be apparent that the arrangement of dot projections on each
character-forming element will be determined in accordance with the
particular characters sought to be produced by the font
assembly.
Both embodiments of the font assembly of the present invention have
been designed to produce 64 characters comprising the dense subset
of the American Standard Code for Information Interchange (ASCII).
As shown in FIG. 14, these consist of the letters A through Z,
Arabic numerals "0" through "9" and various other symbols.
FIG. 2 illustrates schematically one embodiment of the font
assembly of the present invention. As there shown, a dot matrix is
formed from seven character-forming elements or tapes 22
individually designated 1-7, in stacked relationship. The
arrangement of dot projections on each tape 22 is cyclic, 1 cycle
comprising 63 dot print positions, i.e., the arrangement there
shown is repeated every 63 dot print positions. Thus, if each tape
22 is considered a row and the vertically aligned dot print
positions on each of the seven tapes is considered a column, 1
cycle of the dot matrix of this embodiment comprises 7 columns and
63 rows or 441 dot print positions. Each character is adapted to be
formed from a portion of said matrix 5 columns wide, i.e., 7 dot
print positions high and 5 dot print positions across. In practice,
a space of 2 dot print positions is left between two successive
characters on a print line. Thus, each character print position is
effectively 7 dot print positions or dot widths wide, the first and
last dot print position being blanked. In a typical case, the
apparatus will be designed to print 81 characters on a line or, in
other words, each printed line will comprise 7.times.81 or 567 dot
print positions. In this first embodiment each tape 22 is adapted
to slide along wires 30 in increments of 1 dot print position or
multiples thereof.
It will be apparent that the particular arrangement of dot
projections on each of the seven tapes 22 adapted to form the
desired characters is a matter of choice. The arrangement shown in
FIG. 2 is believed to be the most desirable from the standpoint of
overall speed of operation, taking into account the particular dot
makeup of each character to be printed.
It will also be apparent that with the above arrangement each tape
will theoretically never be more than 31 dot print positions away
from its desired or next commanded position. Thus, by utilizing
that applicable portion of each tape 22 (comprising 5 operative dot
print positions) nearest to the appropriate character print
position regardless of which cycle said nearest applicable portion
occurs in, the maximum movement of tapes 22 will be 31 dot print
positions. However, this theory is based on a mode of operation
which for linear tapes has proved to be quite impractical. With
this mode of operation, tapes 22 would have to be realigned
periodically or tapes of infinite length (or an endless tape) would
be needed since there would be no limit to the total movement of a
tape to the right or left of a reference position and such tapes
might stray in either direction indefinitely.
Accordingly, the contemplated mode of operation is to limit each
tape 22 to a total net movement within 1 cycle. For this purpose a
reference or standby position for each tape is established such
that the combined movements of a tape to the left and right of its
reference position never exceeds 62 dot print positions. For
purposes of the following illustration it will be assumed that the
tapes as shown in FIG. 2 are each in their extreme left-hand
position with respect to their reference positions. Thus, the
maximum movement of any given tape 22 necessary to form any given
character starting from the positions shown in FIG. 1 at any given
character print position is 62 dot print positions. Accordingly, in
order for the font assembly to print 81 characters (567 dot print
positions or 9 cycles) to a line, each tape 22 is provided with 10
cycles (630 dot print positions) on its operative printing
surface.
By way of example, FIG. 3 illustrates the formation of the
character "F" from the dot matrix of FIG. 2. Referring to each of
the 63 dot print positions in a cycle by number, it can be seen
that the operative print positions for the character "F" consists
of positions 1-7 on tape 1, positions 57-63 on tape 4 and positions
38-44 on tapes 2, 3, 5, 6 and 7. In practice, the initial position
of each tape 22 will be determined by the previously printed
character and its character print position. The logic is
accordingly programmed to move tapes 22 from their initial
positions to bring the aforementioned dot print positions into
alignment at the desired character print position. For the present
example, however, it is assumed that the initial position of tapes
22 is that shown in FIG. 2.
Referring now to FIGS. 2 and 3 the character "F" is formed at a
character print position n which is arbitrarily shown corresponding
to dot print positions 46-52 on all seven tapes 22 in their initial
positions (FIG. 2). Thus, the nearest applicable portion of each
tape 22 will be moved to character print position n without,
however, moving any tape beyond its 1-cycle total movement limit.
In the present example this means all tapes must be moved to the
right. Accordingly, tape 1 will be moved 45 dot widths to the
right, tape 4 will be moved 52 dot widths to the right, and tapes
2, 3, 5, 6 and 7 will each be moved 8 dot widths to the right to
form the character "F" illustrated in FIG. 3. It will be noted that
the nearest applicable portion of tapes 1 and 4 occurred in cycles
N+1 and N respectively. However, utilization of these nearest
portions would have involved a movement of such tapes to the left
which, in accordance with our example, is prohibited by the rule
limiting total tape movement. Thus, the corresponding portions of
tapes 1 and 4 in cycles N and N-1 respectively were utilized.
In practice, each dot print position is typically 0.014 inch wide
so that the largest movement involved in the transition from the
dot matrix shown in FIG. 2 to that shown in FIG. 3 is 52 dot widths
or 0.728 inch (52.times.0.014 inch). The maximum possible movement
of any tape for any given formation using the foregoing mode of
operation is thus 62.times..014 or 0.868 inch.
Accordingly, it can be seen that the dot matrix font assembly of
FIG. 2 is designed to provide a high-speed formation of any one of
64 discrete characters with a maximum linear movement of less than
1 inch for each character-forming element 22.
FIG. 4 illustrates a second embodiment of a dot matrix for use with
the font assembly of the present invention. As there shown, the dot
print positions on each tape 22 are arranged in groups of 7, the
first and last position of each group being blanked. Thus, in
contrast to the first embodiment described above, the tapes 22 are
adapted to be moved in increments of 7 dot widths (i.e. 1 character
width) or multiples thereof so that each character is formed by the
alignment of a given group of dot print positions on each tape 22.
As shown in FIG. 4, 1 cycle of dot projections consists of 14 such
groups of 7 or 98 dot print positions. Again the maximum movement
of each tape 22 from an established reference position is limited
to a combined movement to the right and left of a reference
position of 13 groups (91 dot widths). Accordingly, to print 81
characters to a line, each tape is provided with 95 such groups or
1 cycle more than the width of a printed line.
For the purpose of this example it will again be assumed that each
tape is shown in FIG. 4 in its extreme left-hand position the net
movement (combined movements to the left and right of a reference
position) of each tape being limited to 13 groups (91 dot print
positions). FIG. 5 shows the character "F" formed from the dot
matrix of FIG. 4. Referring to each group by number, it will be
seen that the character "F" requires the alignment of group 1 on
tape 1, group 14 on tape 4 and group 7 on tapes 2, 3, 5, 6, and 7.
Thus, for example, if the character position n is arbitrarily
picked to be that corresponding to the initial position of group 10
on all tapes as shown in FIG. 4, tape 1 would be moved 9 groups (63
dot widths) to the right, tape 4 would be moved 10 groups (70 dot
widths) to the right and tapes 2, 3, 5, 6, and 7 would be moved 3
groups (21 dot widths) to the right. Again it will be noted that,
in accordance with the rule limiting total tape movement, groups 1
and 14 in cycles N and N-1 respectively, rather than the nearest
corresponding groups in cycles N+1 and N respectively, were
utilized.
It will be apparent that the dot arrangement of FIG. 4 involves a
greater maximum movement of tapes for forming a sequence of
characters. Thus, the maximum movement in this case is 91 dot
widths (0.014.times.91) or 1.274 inches. However, by providing only
14 discrete selectable positions in each cycle (as opposed to 63 in
the previous embodiment) the complexity and cost of the control
logic may be reduced considerably. This embodiment, therefore,
sacrifices some speed for simplicity of operation.
As best shown in FIG. 7, the font assembly is actuated by a drive
mechanism generally designated 34 mounted on housing 10 directly
behind slot 26 by fastening means 36. While several types of drive
mechanisms may be used, it has been found that mechanisms of the
type known as linear translation motors are most effective for this
purpose. Motors of this type are adapted to rapidly position a
metallic member by selectively actuating a plurality of
electromagnets under a magnetic platen. One advantage of motors of
this type is that there need be no mechanical connection between
the motor and the driven part. In addition, such motors are adapted
to produce extremely small, accurate, incremental linear movements
with the number of increments of each discrete movement being
variable by electronic control signals. An example of one such
motor is that disclosed in U.S. Pat. No. 3,376,578 issued on Apr.
2, 1968 to Bruce A. Sawyer. Each tape 22 is driven by its own motor
34, only one such motor (driving the top tape 22) being illustrated
in FIGS. 7 and 8 for the sake of simplicity.
As best shown in FIGS. 10 and 11, each tape 22 is provided with a
tongue 38 which is suitably positioned with respect to motor 34 in
operative driving relationship (see arrows in FIG. 11). As
illustrated in FIG. 10, tongues 38 extend from the rear of each of
the seven tapes 22 in staggered relationship to accommodate seven
motors in correspondingly staggered relationship. In the event the
motors used are too large to be accommodated by the arrangement
shown, they may be staggered in depth or in any other convenient
manner. It should be noted that each motor 34 must be adapted to
move its corresponding tape 22 within 1 cycle of its reference
position.
Once tapes 22 are in a position forming the desired character at a
given character print position, the printing surface of the
operative portion of the matrix is adapted to be impacted against
paper 14 and inked ribbon 15 to produce the character image on
paper 14. For this purpose hammer assembly 12 comprises a plurality
of hammers H, three such hammers being shown in the preferred
embodiment and designated H1, H2 and H3, respectively. As best
shown in FIG. 7, each hammer is "F"-shaped and comprises a base
portion 39 and two legs 40 and 42 extending horizontally toward
font assembly 10. The upper leg 40 comprises the operative impact
or hammerhead adapted to engage ribbon 15 and press it against
paper 14 and the operative printing surfaces of tapes 22. Housing
24 is provided with a bumper strip 44 of resilient material such as
hard rubber or elastic metal below slot 26, aligned with the lower
legs 42 of hammers H. Bumper strip 44 serves two purposes: first,
it provides an impact force on leg 42 to counterbalance the impact
force exerted by tapes 22 on leg 40 which would otherwise result in
a damaging torque on hammer H and its actuating mechanisms; second,
the resiliency of bumper strip 44 assists in rapidly returning
hammers H to their cocked positions after impact.
Referring to FIG. 9 the base portion 39 of hammer H is provided
with a flange 46 and is slidably mounted within a correspondingly
shaped slot 48 in a mounting in the form of an inverted "T"-shaped
shoe 50. The bottom surface of slot 48 is lined with a low-friction
material such as Teflon or the like to provide a low-friction
bearing surface 52 upon which hammer H is adapted to rapidly
reciprocate to intermittently impact against font assembly 10 at
the desired character print position.
Each hammer is adapted to be moved longitudinally (as viewed in
FIG. 1) along a given portion of font assembly 10, the hammer H2
taking over where hammer H1 leaves off and hammer H3 taking over
where hammer H2 leaves off. In this manner, during the printing of
a given line each hammer H will have sufficient time to return to
its initial left-hand position in preparation for printing of the
next line. Since a line is printed from left to right and since a
printed line may terminate short of the 81st character position, it
is desirable to design the left-hand hammer H1 to travel a
substantially smaller distance along font assembly 10 than hammers
H2 and H3. Thus, if a printed line terminates after a character
printed by hammer H1, the return time of hammer H1 will be small
and there will be little or no delay in the commencement of the
next line of print.
In order to provide for the longitudinal movement of hammers H, a
track 54 is mounted below the hammers parallel to font assembly 10.
As best shown in FIGS. 7 and 8, track 54 is provided with a channel
or slot 60 adapted to slidingly receive the base of shoe 50.
Bearing means 62 are provided between shoe 50 and the lower surface
of slot 60 to facilitate rapid sliding engagement. As best seen in
FIG. 1, shoes 50 carrying hammers H1, and H3 are both slidingly
mounted on track 54 in this manner. A second track 56 identical to
track 54 is provided forwardly (out of the paper as viewed in FIG.
1) of track 54 and is adapted to mount shoe 50 carrying the middle
hammer H2 in the same fashion. Legs 40 and 42 of hammer H2 are
accordingly designed longer than their counterparts on hammers H1
and H3 so as to span track 54. With this arrangement, hammers H2
and H3 are adapted to take over printing from hammers H1 and H2,
respectively, in the next character position without interference
of their respective shoes 50.
The positions of hammers H1, H2 and H3 along tracks 54 and 56 are
controlled by individual linear drive means generally designated 64
(see FIG. 7). Drive means 64 are preferably linear translation
motors of the type already described with respect to the actuation
of character-forming tapes 22. As illustrated in FIG. 7, motor 64
is mounted directly under track 54 and is adapted to move shoe 50
along track 54 by means of selectable actuation of electromagnets
as previously described. In the case illustrated track 54 and shoe
50 would be made of suitable material to provide such magnetic
actuation. Alternatively, shoe 50 might be provided with a tongue
extending through a longitudinal slot in track 54, the tongue being
actuated magnetically or by suitable physical drive means. In
either case, shoes 50 and thus hammers H must be movable in
accurate increments of 1 character width (7 dot widths) and
multiples thereof.
Each hammer H is provided with a "T"-shaped slot 65 at its base
portion 39 slidably receiving a correspondingly "T"-shaped impact
bar 66 which is adapted to reciprocate its respective hammer within
shoe 50 toward and away from font assembly 10. Impact bars 66 are
in turn actuated through arms 68 by a pair of solenoids S, three
such pairs of solenoids S1, S2 and S3 being shown in FIG. 1 adapted
to actuate hammers H1, H2, and H3, respectively. Two solenoids are
provided for each impact bar 66 to produce a balanced impact force
on such bars to thereby prevent an undesirable torque which might
produce binding between slots 65 and bars 66. As shown in FIG. 7,
the impact heads on hammers H are spaced only a very small distance
from the operative printing surface of font assembly 10.
Accordingly, solenoids S are designed to produce an extremely rapid
short reciprocating stroke, the impact position of hammers H being
illustrated in FIG. 8.
The operation of the foregoing apparatus will now be apparent. When
a character is to be printed at any one of the 81 character
positions on paper 14, each of the seven tapes 22 is moved by means
of motors 34 a distance such that the applicable dot arrangement
appears at such character position, the aligned dot projections on
each tape forming the desired dot matrix. At the same time the
hammer H operating along the applicable span of character positions
is moved by means of motors 64 along track 54 or 56 and impact bars
66 to the applicable character position opposite the operative
portion of the dot matrix. The hammer H is then rapidly
reciprocated by solenoid S within slot 48 in shoe 50 to impact
against ribbon 15, paper 14, and the operative dot matrix on font
assembly 10. The desired character is thus imprinted on paper 14.
This process is repeated for the next character to be printed. As
each hammer reaches its terminal right-hand position, it is rapidly
returned to its initial left-hand position by means of its drive
motor 64 and the next hammer, already disposed in the next adjacent
character position, begins actuation. Ribbon 15 is fed periodically
in any desired manner to provide a fresh ribbon portion at the
applicable character print position during each impact. As the end
of a printed line is reached, paper 14 is fed by sprocket roll 16
the desired number of lines and hammer H1 begins printing the next
line.
The aforementioned procedure is carried out at extremely high
speeds under the control of electronic logic means. FIG. 13
illustrates schematically the operation of a preferred embodiment
of such logic means, the detailed circuitry being apparent to those
skilled in the art and, therefore, omitted for the sake of
simplicity. As there shown, the logic is adapted to control all the
aforementioned operations in accordance with a data input
signal.
It should be noted that additional logic may be needed to
incorporate the printing apparatus of the present invention into a
complete communications terminal. However, the present description
is limited to the operation of the printer itself as many
possibilities of such incorporation will be apparent to those
skilled in the art.
When, as will usually be the case, the present apparatus is used in
connection with the printout from high-speed electronic
data-processing equipment the input signal will usually be in the
form of a plurality of binary data signals representing the data to
be printed in the desired sequence. This raw data signal must be
processed and converted into a form intelligible for the purpose of
commanding the various operations of the printing apparatus.
Accordingly, an input signal processor 68 is provided for this
purpose. Processor 68 is adapted to receive and store incoming data
and translate such data into appropriate command signals. In the
present embodiment the command signals are classified into two
types: (1) mechanical commands, involving a positioning of the
hammers (i.e. carriage return, space, tab, etc.) or paper (line
feed) but not a printing operation, and (2) print commands,
involving the printing of a particular character at a given
character print position. The processed mechanical and print
command signals are transmitted via lead 71 to a sequence command
logic means 72. Sequence command logic 72 is the master command
logic and is programmed to accept processed input signals and to
transmit control signals to the appropriate control logic systems
in the proper sequence. In addition, the print command signals are
transmitted via lead 74 to the type font assembly command logic 76.
At this point the print command signals are further broken down
into character commands and location commands. Thus command signals
transmitted via lead 74 are character commands, i.e., they contain
instructions only as to the character to be printed. The location
or character print position at which such character is to be
printed (location command) emanates from sequence command logic 72
which is programmed to provide spacing between individual words,
align columns of numerical data, paragraph, etc.
In practice, the type font assembly control logic, in response to
character commands, is programmed to read out from memory data
corresponding to the required position of each of the seven tapes
for forming a given character at a reference character print
position. This data signal is then amended by means of a shift
register under the control of the sequence command logic to add or
subtract that number of character print positions defining the
difference between the reference character print position and the
commanded character print position. While it is possible for all
commands to be directly transmitted to the proper control logic
systems through sequence command logic 72, the system illustrated
permits the initiation of print commands simultaneously with the
execution of mechanical commands. Thus, input processor 68 is
adapted to store up to four or five sequential data input signals.
If the next command to be executed is a mechanical command, the
processor will "look ahead" to the next subsequent print command
and transmit the corresponding character command via lead 74 to the
type font assembly command logic 76. Sequence command logic 72 will
in turn transmit the appropriate location command to font assembly
command logic 76 which initiates the appropriate tape-positioning
commands required to print the commanded character at the desired
location.
The motor assemblies for both the tapes 22 and hammers H are
provided with position-encoding subassemblies 80 and 82
respectively, comprising position encoder means for each tape and
hammer respectively. These position signals are transmitted to tape
and hammer position monitors 84 and 86, respectively, via leads 88
and 90, respectively. These position monitors are adapted to
provide continuous reference data on current tape and hammer
position and in addition to transmit an initiation signal to the
sequence command logic 72 via leads 92 and 94, respectively, when
the tapes and hammers have reached their commanded positions.
Tape movement is controlled by the tape control logic designated
96, which receives tape position command signals from type font
assembly command logic 76 via lead 98 and current tape position
signals from tape position monitors 92 via lead 100. The commanded
position is compared to the current position of each tape 22 and a
tape control signal is transmitted via lead 102 to tape linear
translation motors 34 to move each of the seven tapes to their
commanded positions.
Hammer positioning is controlled by hammer control logic 104 which
receives hammer position command signals from sequence command
logic 72 via lead 106 and current hammer position signals from
hammer position monitors 86 via lead 108. The commanded position is
compared to the current position and a hammer control signal is
transmitted to hammer linear translation motors 64.
If the command is a print command, the sequence command logic 72,
upon receipt of initiation signals from tape and hammer position
monitors 84 and 86, will transmit an impact signal via lead 110 to
the impact solenoid assembly to actuate the proper impact
solenoid.
Sequence command logic 72 is also adapted to control the paper and
ribbon feed assemblies in any desired manner via leads 112 and 114,
respectively. For example, the sequence command logic 72 would
normally be programmed to initiate ribbon feed a given number of
character print positions when a particular character print
position is reached. Likewise, paper 14 would normally be fed one
line after the 81st character print position but this would be
variable in accordance with the input data.
It will be apparent from the foregoing that a printing apparatus
has been designed to print data at extremely high speeds utilizing
a reliable and accurate mechanical mode of operation. By utilizing
a dot matrix font assembly, it is possible to print any desired
sequence of characters utilizing a maximum mechanical movement in
the order of 1 inch. Because each character is formed from a series
of dots, the individual character-forming elements each containing
one row of dot projections are extremely thin and thus light. This
small mass and small maximum distance enables said elements to be
moved at extremely high speeds with low-power drive equipment. Thus
an average line of 81 characters may be printed, utilizing the
apparatus of the present invention, in less than 1 second.
The utilization of linear motion and magnetic drive means reduces
wear and likelihood of mechanical breakdown. Moreover, by reducing
the number of moving parts, maintenance costs are reduced
considerably.
The present apparatus is particularly suited for printing data
emanating from high-speed electronic data-processing equipment.
While only two embodiments of the present invention have been here
specifically described, it will be apparent that many variations
may be made therein, all within the scope of the instant invention
as defined in the following claims.
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