U.S. patent number 3,688,672 [Application Number 05/022,649] was granted by the patent office on 1972-09-05 for keyboard operated phototypesetting display machine.
This patent grant is currently assigned to Compugraphic Corporation, Wilmington, MA. Invention is credited to Ellis P. Hanson, George J. H. Sausele.
United States Patent |
3,688,672 |
|
September 5, 1972 |
KEYBOARD OPERATED PHOTOTYPESETTING DISPLAY MACHINE
Abstract
The keyboard operated phototypesetting display machine produces
continuous photographic paper output copy in 15 to 72 point range
sizes which is top-aligned for all point sizes. A continuous
rotating drum supports a font strip containing two rows of
characters, timing slits, and coded data indicating the width of
each of the characters. The selected characters are strobed to a
magnifying lens and projected onto an image plane containing the
photographic paper. The desired point sizes are obtained from
individual lenses which are mounted on a rotatable lens turret
which is located and locked to position a lens at a lens station by
a point size selector knob. The spacing of the projected images of
the characters is determined by a photoconductive pick-up which
senses the character width information on the font strip and also
by coded signals from the keyboard. Computer and control circuitry
automatically determines the correct spacing to energize a stepping
motor to escape the photographic paper. Means are provided whereby
the letterspace escapement may be automatically decreased in
selectable increments for all point sizes. The photographic paper
is loaded at the image plane from a cassette and the output copy is
received, in turn, into another cassette for easy removal from the
machine. A cutter mechanism is provided to sever the paper after a
"take."
Inventors: |
Ellis P. Hanson (Rockport,
MA), George J. H. Sausele (Lynnfield, MA) |
Assignee: |
Compugraphic Corporation,
Wilmington, MA (N/A)
|
Family
ID: |
21810688 |
Appl.
No.: |
05/022,649 |
Filed: |
March 25, 1970 |
Current U.S.
Class: |
396/554; 396/560;
355/55 |
Current CPC
Class: |
B41B
27/28 (20130101); B41B 17/10 (20130101); B41B
17/42 (20130101) |
Current International
Class: |
B41B
27/28 (20060101); B41B 27/00 (20060101); B41B
17/00 (20060101); B41B 17/42 (20060101); B41B
17/10 (20060101); B41b 015/08 (); B41b
017/00 () |
Field of
Search: |
;95/4.5R ;355/55 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Samuel S. Matthews
Assistant Examiner: Robert P. Greiner
Attorney, Agent or Firm: Watson, Cole, Grindle &
Watson
Claims
What we claim is:
1. A phototypesetting machine for producing proportionally spaced
type composition on a photosensitive strip, comprising: means for
providing input signals representing selected characters and
control functions, means for carrying master character images,
means to select desired character images from said means for
carrying by strobing said character images with a pulse of light,
means for projecting said selected character images onto said
photosensitive strip, means for advancing said photosensitive strip
a distance required by the projected character width, and means for
controlling said means to select and said means for advancing
respectively in accordance with said input signals and said
distance required by the projected character width, said means for
projecting include means for varying the size of said projected
character images to produce a selectable range of point size images
on said photosensitive strip, said means for controlling include
means for generating escapement signals proportional to the size of
said projected character image for energizing said means for
advancing to vary the distance required by the projected character
width, and said means for generating escapement signals include
means for modifying said escapement signals independently of the
size of said projected character image.
2. A phototypesetting machine for producing proportionally spaced
type composition on a photosensitive strip, comprising: means for
providing input signals representing selected characters and
control functions, means for carrying master character images,
means to select desired character images from said means for
carrying by strobing said character images with a pulse of light,
means for projecting said selected character images onto said
photosensitive strip, means for advancing said photosensitive strip
a distance required by the projected character width, means for
controlling said means to select and said means for advancing
respectively in accordance with said input signals and said
distance required by the projected character width, said means for
projecting include means for varying the size of said projected
character images to produce a selectable range of point size images
on said photosensitive strip, said means for controlling include
means for generating escapement signals proportional to the size of
said projected character image for energizing said means for
advancing to vary the distance required by the projected character
width, said means for controlling further includes switching means
having three positions, said means for generating escapement
signals further includes means for modifying said escapement
signals in proportion to the size of said projected image and means
for modifying said escapement signals independently of the size of
said projected image, the first position of said switching means
providing escapement signals determined in proportion to the size
of said projected character image, the second position of said
switching means providing escapement signals modified in accordance
with the size of said projected image, and the third position of
said switching means providing escapement signals modified
independently of the size of said projected character image.
3. A phototypesetting machine for producing proportionally spaced
type composition on a photosensitive strip wherein characters are
selected from a master character carrier and are projected to a
photosensitive strip in different selectable size images,
comprising: means for advancing the photosensitive strip a distance
required by the projection character width, and said means for
advancing including means for generating escapement signals and
means for modifying said escapement signals independently of the
size of said projected character image.
4. A phototypesetting machine as in claim 3 wherein said means for
generating escapement signals further includes switching means
having three positions, said means for generating escapement
signals further includes means for modifying said escapement
signals in proportion to the size of said projected image and means
for modifying said escapement signals independently of the size of
said projected image, the first position of said switching means
providing escapement signals determined in proportion to the size
of said projected character image, the second position of said
switching means providing escapement signals modified in accordance
with the size of said projected image, and the third position of
said switching means providing escapement signals modified
independently of the size of said projected character image.
5. A phototypesetting machine as in claim 3 wherein said master
character carrier includes different character styles and different
character widths for the characters of each character style further
comprising means for sensing said character width, means for
storing the sensed character widths, and means for delaying the
transmission of said character widths from said master character
carrier to said means for storing whereby the character width
associated with each character is sensed.
Description
This invention relates to keyboard operated phototypesetting
display machines and, in particular, to such machines which produce
continuous photographic paper output copy with a variable point
size range wherein top-of-body alignment is provided for all point
sizes.
An advantageous feature of the phototypesetting machine of this
invention is that it is the first machine of its type which enables
a headline strip output to be obtained from a keyboard input. Prior
art headline strip machines require manual manipulation of a
character storage means in order to select characters for a desired
output. These manual prior art machines are known as photolettering
machines such as, for example, the AM Headliner, Typro (a
registered trademark), the Friden Typro, etc. The keyboard operated
phototypesetting display machine disclosed herein represents a
vastly superior product over the prior art photolettering machines
as will be evident to those skilled in the art from the following
description.
A direct input keyboard is an integral part of the photo unit and
provides a production capability heretofore unattainable in the
larger point sizes. Keyboard input speed ranges from 3 characters
per second in 72 point to 14 characters per second in 15 point. An
eight-lens turret provides instant access to 15, 18, 24, 30, 36,
48, 60 and 72 point sizes. Intercharacter spacing for each point
size is determined automatically by the control circuitry of the
unit. No calculations by the operator are necessary.
The characters appear on font strips, there being two font strips
mounted on a rotating font drum, and which are easily installed and
removed so as to provide a variety of different character types.
One font strip is mounted to the drum in an upper magazine position
and the other font strip is mounted in a lower magazine position.
Each font strip contains two parallelly spaced rails and a given
rail is selected by operating an appropriate lever mechanism on the
control panel.
A nominal character width and timing mark is associated with each
character on the font strips. Photoconductive sensors detect the
timing mark and width data which are processed by the computer to
determine the strobing of the characters and escapement signals for
advancing the paper strip to provide intercharacter spacing. A
three-position switch on the control panel enables the operator to
select an automatic mode wherein character space compensation, in
accordance with the various output point sizes, is determined from
a table stored in the machines; or a mode which enables the
operator to switch in a desired range of character space
compensation values regardless of the point size output; or a mode
in which letterspace compensation is not provided. The
aforementioned modes of operation thereby enable the operator to
vary the intercharacter spacing over a widely variable range.
The paper or film upon which the output is produced is packaged in
a special light-tight throwaway plastic magazine which provides a
400 foot strip and which is installed at a specially designed
cassette receiving station. The output strip is automatically fed
to a cassette receptacle at the front of the machine. Operation of
a paper cutter lever cuts the paper at the "end of a take" thereby
enabling the cassette receptacle to be removed so that the paper or
film may be exposed. The paper is advanced in accordance with the
escapement signals generated by computer circuitry in accordance
with the aforementioned character space calculations by a stepping
motor.
It is a primary object of this invention to provide an automatic
keyboard operated phototypesetting display machine which produces
continuous photographic paper strip output copy.
It is another object to provide such a machine wherein the output
copy is top-of-body aligned. It is yet another object to provide
such a machine having a variable selectable point size output
range. It is yet another object to provide such a machine having
automatic letterspace compensation. A still further object is to
provide such a machine which affords a large number of characters
and a wide variety of character types. It is still yet a further
object to provide such a machine which is considerably faster than
the former manual prior art machines and yet which is inexpensive
to manufacture and maintain.
These and other objects and features of the invention will become
apparent from the following specification and the drawings which
disclose an exemplary embodiment of the invention wherein:
FIG. 1 is a perspective view to illustrate the various component
assemblies of the photocomposing machine;
FIG. 2 is a plan view of the machine illustrated in FIG. 1 showing
the character presentation assembly, the projection lens assembly,
and the paper advance assembly;
FIG. 3 is a side elevational view of the apparatus shown in FIG.
2;
FIG. 4 is a plan view of the font drum shift mechanism;
FIG. 5 is an elevation view of the font drum shift mechanism taken
along lines 5--5 of FIG. 2;
FIG. 6a illustrates the relationship of the timing marks, character
width information, and negative character images on the font
strip;
FIG. 6b illustrates another embodiment of the font strip;
FIG. 7 is an enlarged plan view showing the relationship of the
flash lamp assembly, the photoconductive detectors, the font strip,
the aperture mask and screen, and the lens station of the character
presentation assembly shown in FIG. 2;
FIG. 8 is an elevation view of the mechanism for retaining in a
selected position the lens turret of the projection lens assembly
shown in FIGS. 2 and 3;
FIG. 9 is a sectional view of the paper feed guide and paper feed
mechanisms of the paper advance assembly taken along line 9--9 of
FIG. 2;
FIG. 10 is a side elevation view of the cutter blade assembly
associated with the paper advance assembly illustrated in FIG.
1;
FIG. 11 illustrates the cutter blade;
FIG. 12a is a representation of the manner in which the
photographic output of the display machine is assembled to form a
"paste-up";
FIG. 12b shows the relationship of the character image at the font
strip to its image at the image plane with respect to the optical
axis; and
FIGS. 13 and 14 are combined block diagrams and schematics of the
computer and control circuitry of the phototypesetting display
machine.
GENERAL DESCRIPTION
FIG. 1 illustrates the primary components of the phototypesetting
display output machine wherein base 20, which includes the
necessary power supplies and computer and control circuitry to
operate the machine, supports a frame 22 to which is mounted
photo-unit assembly 24, keyboard 26, and control panel 28. A cover
(not shown) encloses photo-unit assembly 24 to exclude extraneous
and unwanted light therefrom.
Photo-unit assembly 24 consists of three subassemblies; character
presentation assembly 30, projection lens assembly 32, and paper
advance assembly 34. Character presentation assembly 30 includes
font drum 40 which continually rotates in a plane normal to the
character top line which is established at a fixed image plane
within paper advance assembly 34. Font strip 42 is accurately
positioned on font drum 40 and contains two rows of characters, the
necessary timing slits to provide synchronization signals to the
computer and control circuitry for strobing the selected
characters, as well as the character width information for
appropriately escaping the photographic paper. A mechanism is
provided which enables font drum 40 to be laterally shifted to one
of two positions whereby a desired one of the two rows of
characters is positioned to be presented to projection lens
assembly 32 so that a selected character may be strobed and
projected to the image plane within paper advance assembly 34. Font
drum 40 is manually rotatable by knob 43 for the purpose of
initially aligning the machine for test purposes.
Projection lens assembly 32 includes a rotating turret assembly 50
on which are mounted a plurality of lenses each having a different
power of magnification. Turret assembly 50 is rotated to a desired
position by manual operation of turret knob 52, thereby enabling a
desired character size, variable from 15 to 72 point, to be
projected onto the image plane within paper advance assembly 34.
Four lower magnification lenses are mounted on one side of turret
assembly 50 and the four remaining higher magnification lenses are
mounted on the opposite side of the turret assembly as will be more
fully described hereinafter.
Cartridge holder 58 receives and retains a 400 foot reel of 35 mm
type S paper which is threaded into paper advance assembly 34 and
into a paper advance mechanism therein. The photosensitive paper or
film is then automatically escaped in accordance with the character
width information on font strip 42 and coded interword spacing
information from the keyboard. Lever 62 operates cutter mechanism
64 to cut the paper at the end of a "take." The photographed paper
is received in a cassette at receiving station 60 for easy removal
from the machine.
The characters to be photographed are selected by depression of the
keys on keyboard 26 which has a standard keyboard layout known to
those skilled in the printing art. The keyboard has 49 printing
keys including "end" mark and "start" mark, as well as an "end
take" key to feed an "end of take" signal into the paper receiver
within paper advance mechanism 34. The various control features of
the keyboard will be described more fully hereinafter with
reference to the computer and control circuitry. A TTS code is
generated in response to the depression of the keys on the keyboard
and decoded by decoder circuitry within the computer.
Control panel 28 contains additional control switches, buttons and
indicators to initialize the computer and indicate to the operator
certain operating conditions of the phototypesetting machine to be
more fully described hereinafter.
DETAILED DESCRIPTION OF CHARACTER PRESENTATION ASSEMBLY
With reference to FIGS. 2 and 3, character presentation assembly 30
further includes shaft 80, rotatably mounted within drum carriage
82, to which is fixed font drum 42. Shaft 80 is rotated
continuously in a direction indicated by the arrow via timing
pulleys 84, 85, timing belt 86, and motor 88 at a speed of
approximately 810 r.p.m. Drum carriage 82 is slidably secured to
guide rods 90, 92 by means of bearings (not shown) to afford
lateral movement of font drum 40. Timing belt 86 is narrower than
the grooves in pulleys 84, 85 to enable the belt to move within the
grooves as drum carriage 82 is moved laterally to either one of two
positions. Guide rods 90, 92 are secured in mounting bracket 94
which is in turn fixed to the machine frame. Knob 43 enables the
operator to manually rotate shaft 80 and font drum 40 to place the
font drum in a convenient position to replace a font strip.
With continuing reference to FIG. 2, and additional reference to
FIGS. 1, 4 and 5, the mechanism for actuating drum carriage 82 to
afford the aforementioned lateral movement of font drum 40 consists
of lever 110 which is pivotally mounted to the machine frame at
pivot 112. Rod 114 is secured at one end 116 thereof to lever 110;
the other end of rod 114 is attached to link 118 which is pivotally
mounted to the machine frame at pivot 120. Line 122 is pivotally
mounted to the machine frame at pivot 124 and to link 118 by pin
126. Leg member 128 connects links 118, 112 to drum carriage 82 by
means of pin 126. Spring 130 is fastened to the outer ends of links
118, 112 by pins 132, 134. The aforedescribed apparatus forms an
over-center mechanism for shifting and locking drum carriage 82 at
opposite ends of its lateral traverse in the following manner.
Lever 110 is pivoted about pivot 112 by manual movement afforded by
handle 136. It is apparent that clockwise rotation of lever 110
causes link 118 to rotate clockwise about pivot 120, thereby moving
links 118, 122 into the position shown in full outline in FIG. 4
and moving drum carriage 82 and font drum 40 upward with reference
to FIG. 2. Spring 130 locks links 118, 122 in their over-center
position. Counterclockwise movement of handle 136 moves links 118,
120 into the position illustrated in phantom in FIG. 4 and produces
an opposite lateral movement of font drum 40. The lateral movement
of font drum 40 is limited in each direction by stops 138, 140
which are respectively driven into abutting relationship with
opposite surfaces of bracket arm 142. The stops ensure that font
drum 40 is accurately located so that each row of characters on
font strip 42 is precisely positioned to present a selected
character to lens projection assembly 32, as will be more fully
described below.
FONT STRIP
Font strip 42 is preferably two strips of dimensionally stable
photographic film on which have been developed negative timing
marks 150 and negative type characters 152 which are provided in
two rails 154, 156 which extend in parallel spaced rows as
indicated in FIG. 6a. Font drum 40 is divided into an upper
magazine 158 and a lower magazine 160 (as illustrated in FIG. 3),
and one font strip is mounted to font drum 40 at each magazine.
Each font strip 42 has 56 characters; therefore, there are 112
characters in each rail 154, 156. The manner by which the font
strips are mounted to font drum 40 is described in copending U. S.
application Ser. No. 804,466, which is assigned to the same
assignee as the present application. Character width information is
afforded in binary coded format by slits 162 which provide six bits
of data thereby enabling a width count of 64, to be indicated.
Timing marks 150, type characters 152, and width information 162
are transparent, thereby enabling light to be projected through
them. Timing marks 150 are positioned with respect to type
characters 152 so as to provide the necessary timing signals to the
computer to enable a selected type character to be strobed at the
proper time and projected in the proper position on the line being
set on the photographic paper at the image plane as font drum 40
rotates continuously. As illustrated in FIG. 6a, the adjacent
characters in rails 154, 156 have the same character width.
Therefore, one set of corresponding bit data is sufficient for the
width information for both of the rails. The two extra timing slits
163, 164 are necessary to set or condition circuitry within the
computer to generate the character strobe signal as will be
described below. The font strip illustrated in FIG. 6a is called a
"duplexed" strip since the same character width information
pertains to the characters in each of the rails 154, 156.
FIG. 6b illustrates a modification of the font strip 42, wherein
the adjacent characters in rails 166, 168 have different character
widths, thereby necessitating two sets of character width
information. The character width information is afforded by
providing one set of character width data for each rail 166, 168.
This is illustrated in FIG. 6b by binary data 169, 170, which,
respectively, contains the width information for the character "t"
in rails 166, 168. Two sets of binary coded data are similarly
provided for the remaining characters in rails 166, 168. The manner
in which the width information for each rail is detected and made
known to the computer is described below.
The characters 152 on the font strip are inverted as they appear to
lens station 178 (FIG. 7) so that their inverted image is
right-side up at the image plane in advance assembly 34.
FIG. 7 illustrates the flash lamp assembly for strobing a selected
character to that lens which has been selected to project the
character onto the image plane; as well as the mechanism whereby
the character width and the timing information on font strip 42 are
sensed to provide the computer and control circuitry with the
necessary signals to strobe the selected character at the precise
instant at which it is positioned for projection; and to generate
the necessary escapement of paper drive mechanism 34 in accordance
with the particular character and point size selected.
Flash lamp 172 is mounted by bracket 174 to the machine frame
behind the two rails of characters on font strip 42 aligned with
aperture 176 so that excitation of the flash lamp projects an image
of the selected character through the aperture to a lens station
178 which is positioned as more fully described below. Aperture
mask 180 is mounted over aperture 176 to provide a clear definition
of the strobed character image to the lens station through aperture
182 in light shield 184. Photoconductive member 186 is mounted so
that the individual photoconductive elements 186a-g thereof are in
alignment with the character width information and timing slits on
font strip 42. Photoconductive element 186a detects timing slits
150 and photoconductive elements 186b-g select the six bit width
data 162. Light source 188 is mounted behind font strip 42 to
provide illumination of the character width and timing information
to project this data to the photoconductive elements 186a-g through
cylindrical lens 190. The photoconductive elements 186a-g, light
source 188 and cylindrical lens 190 are mounted by bracket 192 to
arm 194 of drum carriage 182 to be movable with it, thereby
maintaining the width and timing information in position to be
sensed as font strip 42 is laterally moved to either of its two
positions. Conversely, the mounting of flash lamp 172, aperture
plate 177 and mask 180 to the machine frame positions a desired
rail of characters to be detected as font strip 42 is laterally
moved. The sensed information is provided to the computer control
circuitry for character width control to be more fully described
below. Light shield 184 prevents stray light from reaching the
photosensitive film or paper in advance assembly 34.
PROJECTION LENS ASSEMBLY
Continuing with reference to FIGS. 2 and 3, projection lens
assembly 32 includes turret lens assembly 50 mounted to turret
index shaft 190 which is rotatable within bearing 192. Indexing
shaft 194 has mounted thereon turret indexing gear 196, which
engages idler gear 198, which in turn is engageable with turret
drive gear 200 on shaft 190. Idler gear 198 is rotatably mounted
within arm 202 extending from bearing 192. Thus, a clockwise or
counterclockwise movement of turret knob 52 generates a
corresponding clockwise or counterclockwise rotation of turret
index shaft 190 and turret lens assembly 50.
Turret lens assembly 50 includes eight high-quality lenses 212-219,
which are radially mounted, and spaced equidistantly, on turret
210. In the preferred embodiment of this invention, the
high-quality lenses and their respective focal lengths are selected
to provide a magnification of 10. Thus, to provide a variable
increment in the point size of the paper output copy from 15 to 72,
the lenses respectively, have magnifying powers of 1.5, 1.8, 2.4,
3.0, 3.6, 4.8, 6.0 and 7.2. The lower power lenses, that is, lenses
212-215, are mounted to that side of turret 210 which faces away
from character presentation assembly 30; and the high power lenses,
i.e., lenses 216-219, are mounted to the opposite side of turret
210 so that these lenses are closer to character presentation
assembly 30. The mounting of the lenses to the respective sides of
turret 210 is necessary to afford the proper focal length for the
individual lenses to ensure that the proper magnification is
obtained at the image plane within paper advance assembly 34.
With reference to FIG. 8, turret 210 includes eight detents 220-227
which are equally spaced around the periphery of the turret. Each
detent 220-227 is associated with a respective lens 212-219 to
ensure that each lens will be positively retained in a position to
receive the character images presented by character presentation
assembly 30 and project these images in aligned relationship on the
image plane within paper advance mechanism 34. The retention
mechanism consists of arm 230 which is pivotally mounted at one end
thereof by pivot 232 to the machine frame and which includes roller
234 rotatably mounted at the other end thereof to be in engagement
with the periphery of turret 210. The positive engagement of roller
234 with the peripheral surface of turret 210 is ensured by spring
236. Thus, as turret 210 is rotated by turret knob 52, roller 234
will engage a respective detent 220-227 to retain a selected lens
at lens station 178 (FIG. 7).
For reasons which will become more fully apparent hereinafter, it
is necessary to provide information to the computer which indicates
that particular point size which has been selected by turret knob
52. This information is generated by eight-position switch 240
(FIGS. 2 and 3, the shaft of which is fixed to rotate with indexing
shaft 194, thereby generating electrical signal inputs to the
computer and control circuitry which indicate that particular lens
magnification that has been selected by turret knob 52.
PAPER ADVANCE ASSEMBLY
Paper advance assembly 34 will be described with reference to FIGS.
2 and 9. Cartridge holder 58 is mounted to the side of paper
advance assembly 34 and receives a cassette containing a supply of
35 mm film, the leading edge of which is received in channel 260,
partially formed by paper guide plate 262 and paper backing plate
264. The location of channel 260 is at the image plane 261. With
specific reference to FIG. 9, backing plate shims 266, 268 are
provided to adjust the width of aperture 260. Paper feed keys 270,
272 receive the opposite edges of the paper film to vertically
guide it along channel 260. The paper film in channel 260 is fed
into, and advanced by, paper feed wheel 272 and pressure roller
274. Paper feed wheel 272 is fixed to paper feed shaft 276, mounted
by bracket and bearing assembly 278 to the machine frame, and
driven through gear 280, fixed to the other end of paper feed shaft
276. Gear 280 meshes with, and is driven by, spur gear 282, mounted
to shaft 284, which is stepped by stepping motor 286 in accordance
with control pulses generated by the computer and control circuitry
in a manner to be more fully described below. The paper passes
through transverse cutter slot 290, which is formed by mounting
aperture plate 292 and paper backing plate 294 in spaced
relationship to backing plate 264 and paper guide plate 262,
respectively, so that the channel 260 continues in a straight line
along the aforementioned image plane within paper advance assembly
34.
With particular reference to FIG. 2, pressure roller 274 is fixed
to shaft 296, mounted in roller frame 298, and this frame is
pivotally mounted about roller frame shaft 300 in pressure roller
bracket 302. Pressure roller 302 is fixed to the side of paper
advance assembly 34 as illustrated. Pressure roller stud 304 passes
through roller frame 298 and threadably engages paper guide plate
262 to maintain pressure roller 274 in positive and firm contact
with the film threaded between the pressure roller and paper feed
wheel 272. The unthreading of pressure roller stud 304 enables
roller frame 298 to be rotated away from paper guide plate 262 so
that access is provided to channel 260 and paper feed wheel
272.
The threading of the film in channel 260 through paper feed wheel
272 and pressure roller 274, engages arm 306 of two-position switch
308 to inactivate the switch, thereby affording an indication that
film is loaded and ready for a "take." With no film present in
channel 260, arm 306 is allowed to rotate so as to activate switch
308 thereby providing a "no film" signal which lights an
appropriate indicator on control panel 28 (FIG. 1).
The output display machine includes a paper cutter mechanism for
cutting the paper film after a "take" as is illustrated in FIGS. 2,
10 and 11. The film is severed by blade 310 fixed to cutter shaft
312 within transverse cutter slot 290. Cutter shaft 312 is slidably
mounted within cutter bracket assembly 314 and biased in a downward
position below the paper by spring 316 which has one end abutting
against upper plate 318 of cutter bracket assembly 314, and the
other end fixed to cutter shaft 312 by clamp 320. Blade 310 severs
the paper by a vertical upward movement of cutter shaft 312 as
cutter lever 62 (FIG. 1) is depressed by the operator, thereby
rotating cutter link arm 324 about a pivot (not shown) and
elevating cutter shaft 312 and blade 310.
DISPLAY OUTPUT
FIG. 12 illustrates the manner in which the output of the
phototypesetting machine is utilized to form a "paste-up" display
comprising a number of output strips 350, 352, 354, etc. Strips
350, 352, 354 are assembled in shingled relationship after the film
strips have been developed; the photographic development of the
strips not forming any part of the present invention. The advantage
of using top-of-body alignment is evident in that a successive
strip is overlaid upon the strip immediately preceding in any
desired aligned relationship without the need for any cutting of
the individual strips. The paste-up also illustrates the
versatility of the phototypesetting display machine in that a great
number of character types are selectable in a point size range
extending from 15 to 72 points. Strips 350, 352, 354 are obtainable
from a phototypesetting machine as described herein without the
necessity of changing the font strips on the font drum 40, although
it is apparent that a greater number of character type may be
afforded merely by changing the font strips on the font drum.
The optical system may be aligned in various ways to suit the
particular work to be accomplished. This is readily afforded by
adjusting the lenses 212-219 relative to the member 210. A
preferred and novel alignment is accomplished by aligning the upper
left-hand corner of the type body on a common reference point 362
(FIG. 12a) at or near the top edge of the photosensitive strip 358.
This preferred alignment may be accomplished by placing both point
362 and the corresponding point on the font strip on the optical
axis 360 of the machine. Such an alignment enables setting all
sizes of type close to the edge of the photosensitive strip and for
proper set wise fitting when sizes are changed within a line of
type.
The precision with which optical axis 366 intersects the image
plane is determined primarily by the positioning of a selected lens
at lens station 178 and the accuracy with which the film in channel
260 is maintained in vertical alignment. The necessary accurate
positioning of a lens at lens station 178 (FIG. 3) is provided by
the aforedescribed locking mechanism illustrated in FIG. 8. The
vertical alignment of channel 260 is obtained because the edges of
the film in channel 260 are guided by paper feed keys 270, 272
(FIG. 9).
It is apparent that the film in channel 260 may be escaped to any
position to the right of a former position so that any desired
interword and/or interletter spacing may be obtained by the
appropriate pulsing of stepping motor 286. For example, with
reference to FIG. 12a after the "T" has been strobed, the film may
be advanced so that the optical axis intersects the film at point
368 to enable the next letter, "o," to be strobed onto the film.
The derivation of the escapement pulses in accordance with the
character widths and the automatic letter space compensation value,
which is determined in accordance with the point size and desired
letter spacing, is described below with reference to the
description of the computer and control circuitry.
The relationship of the negative character at the position where it
is strobed at font strip 42 to the projected image at image plane
261 is illustrated in FIG. 12b. It is apparent from the
fundamentals of optics that if the character is strobed at a
position corresponding to that indicated by 370, its inverted image
will appear at position 372 on image plane 261. Therefore, optical
axis 360 may intersect the image plane just below aperture 374 at
paper advance assembly 34. The manner in which the characters are
strobed at the proper instants so that they are projected to the
image plane to be in top-of-body alignment is described below with
reference to the computer and control circuitry.
COMPUTER AND CONTROL CIRCUITRY Character Strobing
The apparatus for determining the proper instant to strobe a
selected character to project it from the font strip to the image
plane, and for computing and controlling the necessary stepping of
the stepper motor to escape the film in accordance with the
character widths and automatic letter space compensation is
illustrated in block and schematic format in FIGS. 13 and 14.
The depression of a key on a keyboard 26 generates a strobe signal
on line 400 which sets LKOUT flip-flop 402 to generate a lockout
pulse (LKP). Simultaneously therewith, the code generated by the
depressed key is fed to keyboard decoder 404 which decodes all the
character codes, space codes, and control functions used to operate
the phototypesetter. For all codes except a space code or a control
function code, the LKP pulse sets FLASH flip-flop 406. FLASH
flip-flop 406 is only set if there is a key depressed which
requires an image on the output film and this condition is
established by the negative SC/CF (Space code/Control function)
signal from decoder 404.
The timing marks on the font strip are detected by the
photoconductive elements of photoconductor 186 (FIG. 7) and
amplified by amplifier and delay circuit 408 to produce negative
clock signals (CLK) and negative delay signals (delay). A
synchronizing pulse is obtained each revolution of the font drum
from an opening between two adjacent ends of the font strips on
font drum 40 to synchronize the computer circuits with the drum
rotation and this pulse sets SYNK flip-flop 412 which produces, in
turn, a flash clear pulse (FCP) and a flash load pulse (FLP) from
delay circuits 414, 415, respectively. FCP resets counter stages
418, 420, 422 of counter 416 through drivers 424, 426, 428. FLP
stores the complement of the keyboard code value, obtained from
inverters 430, into counter stages 418, 420, 422 through drivers
432, 434, 436 and emitter-gated preset drivers 438, 440. This code
represents, by binary designation, each successive character
position for the characters on the font strip, regardless of the
rail in which the character lies. For this purpose, the TTS codes
from the keyboard are assigned numerical values for the font strip
count in accordance with the following tables:
TABLE I CODE DESIGNATION COUNT TTS CODE ON FIGURES 13 & 14
VALUE
_________________________________________________________________________
_ 0 KBO 64 1 KB1 16 2 KB2 8 3 KB3 4 4 KB4 2 5 KB5 1
_________________________________________________________________________
_
each rail of characters on each of the font strips is divided into
two groups, upper case and lower case. The particular group in
which a selected character resides is determined by keyboard
decoder 404 to set upper case flip-flop so that a 32 value is
preset into counter 416 if the selector character is in the upper
case group. For a lower case character no additional count is set
into counter 412. The upper case signal, UC, sets stage "6" of
counter stage 420 through the indicated driver in preset drivers
440 to provide the aforementioned 32 count. Keyboard decoder 404
also sets upper magazine flip-flop 444 to reset a 128 count value
into counter 416 if the selected character lies in the upper
magazine (UM--FIG. 3). This count is set into counter 416 by
resetting stage "7" of counter stage 420 via the indicated driver
in preset drivers 440. In this manner each character in the lower
and upper magazines is designated by a different complement value
set into counter 416, thereby enabling each character on the font
strip to be identified by a corresponding binary designation.
With the aforementioned character position information loaded into
counter 416, clock pulses from clock amplifier 408 are entered into
the first stage ("0") of counter stage 418 via OR gates 507, 508,
until the counter stages 418, 429, 422 are filled up, whereupon the
last stage OF1 of counter stage 422 is set. The next subsequent
clock pulse resets SYNK flip-flop 410 to fire flash tube 172
through driver 446. The character selected from the keyboard is
properly aligned as a result of the counting of the clock pulses
from the beginning of the font strip to the selected character,
whose "position" on the font strip has been stored in counter 416.
The two clock pulses 163, 164 (FIGS. 6a and 6b) which are
interposed between the beginning of the font strip and the third
timing mark opposite the first character thereon are necessary to
account for the setting of stage OF1 and the actual triggering of
flash unit 172 so that the selected character is strobed at the
instant it is in alignment with lens station 178 (FIG. 3).
AUTOMATIC LETTER SPACE COMPENSATION AND CHARACTER ESCAPEMENT
Now that the selected character has been strobed and projected onto
the film into an aligned position, the film must be escaped to
provide the proper positioning for the next selected character.
Before continuing with the description it is advantageous to
provide an explanation of the relationship between the character
widths designated on the font strip, the arithmetic values used by
the computer in deriving the escapement pulses, and the unit values
chosen for the actual escapement itself.
The setwise width is defined in terms of sets and a set is, in
turn, defined in terms of a point. For example, one-set is
equivalent to one-eighteenth of a point; three-set is equivalent to
one-fifty-fourth of a point. The term "EM" is defined as a distance
in points which is equal to the body or height of the type measured
in the setwise direction. A point is defined as one seventy-second
of an inch. The above terminology is that which is used in the
typesetting art; however, the defined units of the set are in
accordance with the units used with the machine disclosed
herein.
In this invention, the character widths indicated on the font strip
are in three-set and the arithmetic in the computer is carried out
on a three-set basis, primarily to obtain better resolution for
defining the escapement pulses. After the computer has performed
the escapement computations, the actual escapement pulses are
determined by a "divide-by-three" circuit to bring the actual
escapement back to one-set. Each step of the film escapement is
equal to one-sixth of a point. This width is, of course, determined
by the characteristics of the stepping motor, the pulses applied
thereto, and the gearing between the motor and the paper advance
mechanism.
LETTERSPACE COMPENSATION
Because the width information designated on the font strip is a
constant or relative value for each respective character, it must
be scaled in accordance with the point size output selected or, in
other words, in accordance with the lens size selected. Such
scaling gives a proportional enlargement or reduction of paper feed
in accordance with the lens size selected. However, such sealing
does not always produce the optimum or desired graphic appearance
for a particular size or style of type. It is desirable to modify
or compensate for the scaled interletter spacing, and even enable
the letter spacing to be varied over a range of increments
regardless of the point size output selected. The phototypesetting
machine described herein provides: (1) a fixed compensation
dependent on the point size output selected, (2) a variable
compensation which is independent of the point size output and is
inserted by manual switches on control panel 28, or (3) no
letterspace compensation.
COMPUTER ESCAPEMENT COMPENSATION
The aforementioned escapement computations are performed in the
following manner. The previously described resetting of FLASH
flip-flop 406 turns on first escape flip-flop 450 to generate
escapement clear pulses (ECP), escapement load pulses (ELP), and
their negative counterparts (ECP, ELP) from delay circuits 452,
454, respectively. ECP clears counter 416 by means of OR gate 456,
driver 458, and drivers 424, 426 and 428. ECP clears counter 460
and, more particularly, counter stages 462 and 464 thereof through
inverter 466 and drivers 468, 470, and 472. The width codes (FIG.
6a) overlap the timing marks and the aforedescribed pulse ECP gates
the appropriate width code into width register 476.
The character width data sensed by the aforedescribed
photo-sensitive elements 186b-g, is amplified by photo-unit
amplifier 410 and gated by switch 474 into width register 476. The
positive escapement load pulse is provided to the gate 478 and
driver 480 to transfer the width information in counter 416 into
stage 418 and the first two stages of stage 420 of counter 416 by
means of drivers 482. The negative escapement load pulse is applied
to inverter 484 and, by means of driver 486, activates drivers 488
to transfer a lens size subtraction or a selected value complement
into counter stage 462 and the first two stages of counter stage
464 of counter 460 from lens size subtraction matrix 490. The
negative escapement load pulse also is applied to inverter 492 and
driver 494 to activate drivers 496, thereby loading a lens size
scaling factor complement into the last stage of counter stage 420
and the stages of counter stage 422. The lens size scaling factor
complement is obtained from lens multiplier matrix 498. The lens
size is provided to lens multiplier matrix 498 by means of the
aforementioned eight-position switch 240 which is driven by the
turret knob indexing shaft 194 (FIG. 2).
The activation of first escapement flip-flop 450 and ECP and ELP
also activate speed-up oscillator 500 by means of AND gate 502 as
indicated in FIG. 14. Speed-up oscillator 500 then generates 3,000
Hz pulses which are counted in counter stage 462 of counter 460
after being delayed in delay circuit 504, and counter 416 counts
the inverted oscillator pulses from inverter 506 by means of OR
gate 508. The counter stages 418, 420, of counter 416 count the
oscillator 500 pulses until the subtraction value is counted in,
since the complement of the width value was originally transferred
from width register 476; if the third counting stage of counter 420
sets, count escapement operating pulse (CEOP) reloads the value
from width register 476 into the first stages 418 and the first two
stages of counter stage 420 of counter 416 and resets the third
stage of counter stage 420 to add one count to the higher
multiplying factor stage 422. A pulse, count escapement operating
pulse plus two (CEOP+2), is provided by delay through circuits 522,
524 to add one count to counter 416 by means of OR gate 508. The
value in counter 416 is therefore the width complement value plus
one and the aforementioned oscillator pulses from speed-up
oscillator 500 again begin to cycle counter 416 and counter 460.
During this count cycling, counter 460 will eventually overflow,
thereby setting the third stage of counter stage 464 to produce a
signal PNY 64 which resets first escapement flip-flop 450 to
thereby set second escapement flip-flop 530 to activate a second
speed-up oscillator 532. Signal PNY 64 determines the end of the
above-described subtraction process.
Counter 416 continues to cycle; however, oscillator pulses from the
second speed-up oscillator 532 step motor driver flip-flops 534,
536. Motor driver flip-flops 534, 536 divide the second oscillator
pulses by a factor of three for operation of the stepping motor
control flip-flops 538, 540 as well as the motor supply switch 542.
Motor supply switch 542 applies a negative 40 -volt output to the
coils of stepping motor 550 during the first 500 microseconds of a
step pulse, and then maintains a holding voltage of minus 12 volts
on the coils, thereby ensuring positive stepping action with a low
holding current.
The compensated escapement value remaining in counter stage 422
after the above-described counting operations, is incremented by
pulses from the second speed-up oscillator 532 via OR gate 508
through stages 418 and 420. Eventually, the last stage of counter
stage 422 will be set, thereby setting flip-flop 560. The output
from flip-flop 560, plus the trailing edge of the counter
escapement operating pulse, resets second escapement flip-flop 530,
thereby terminating the escapement operation as speed-up oscillator
532 is turned off. The resetting of the second escapement flip-flop
530 also resets LKOUT flip-flop 402 and energizes a key release
solenoid until the aforementioned strobe signal on line 400
disappears. The phototypesetting machine is now ready for another
keyboard entry whereupon the above-described operations are
repeated.
The following examples of actual escapement calculations
demonstrate the above-described arithmetic letter space
compensation in detail for an additional understanding of that
portion of the computer circuitry. In the first example, the lens
size subtraction value is greater than the nominal character width
value; and in the second example, the lens size subtraction value
is less than the nominal character width value.
EXAMPLE NO. 1
In this example, the nominal character width is arbitrarily
selected as 54, which is the three-set value of an EM. The lens
size subtraction value is arbitrarily chosen to be 60. The
character width value 54 is stored in counter stages 418 and 420 as
a complement value by setting stages "0" and "3." This is
accomplished by ELP activating the appropriate driver stages
associated with each of the aforementioned counter stages as
indicated in FIG. 14. ELP stores the lens size subtracting value 60
in counter stages "4," " 8," " 16" and "32," respectively, of
counter stages 462 and 464. Pulses from oscillator 500 are
simultaneously counted into both counters 460 and 416. Also, ELP
stores a multiplication value from lens multiplier matrix 498 in
422; the value depending on what point size has been selected and
in accordance with Table III below.
Because the lens size subtraction value is greater than the
character width value, counter stages 418 and 420 cycle first.
Thus, on the 55th oscillator pulse, counter stage CNT6 sets,
thereby triggering counter escapement pulse generator 510, by
removing CNT6, and generating a delayed CEOP pulse and an
additionally delayed pulse CEOP+2. CEOP re-stores the nominal
character width value into the aforementioned stages of counter
stages 418 and 420; immediately thereafter, CEOP+2, via OR gate
508, increments counter stage 418 by a count of one. The
aforementioned setting of stage CNT6 generated an overflow from
counter stage 420 which was carried into the first stage of counter
stage 422. At the setting of CNT6 there remained a deficit count of
six in counter stages 462 and 464. The aforementioned CEOP and
CEOP+2 pulses are interposed between successive oscillator pulses
from oscillator 532. Therefore, the oscillator pulse, immediately
following the oscillator pulse which set stage CNT6, and the
subsequent oscillator pulses are simultaneously counted again into
counters 460 and 416. However, on the fifth oscillator pulse
counter 460 will be filled up; on the sixth oscillator pulse
counter stage "64" will set, which produces signal PNY64. PNY 64
resets first escapement flip-flop 450 thereby setting second
escapement flip-flop 530 to activate escapement pulse oscillator
532.
There is remaining a deficit value of 47 in counter stages 418 and
420 of counter 416. The oscillator pulses from oscillator 532 are
now applied to these counter stages via OR gate 508. After the 48th
pulse, the CNT6 stage will set causing CEOP, CEOP+2 to be generated
which re-strobes width data back into counter 416 if there is still
a deficit value in counter stage 422. This cycle continues until
the multiplication factor is complete. Eventually, the last stage
of counter stage 422 is set, thereby setting escapement terminating
flip-flop 560. The setting of flip-flop 560 resets second
escapement flip-flop 530 thereby deactivating escapement oscillator
532 to terminate the stepping of the stepping motor of the
escapement of the escapement film.
EXAMPLE NO. 2
In this example, the nominal character width remains at 54;
however, the lens size subtraction value is arbitrarily selected as
30. The character width value, the lens size subtraction value, and
the multiplication value, are inserted into their respective
counters as described above with reference to Example 1, the only
difference being that the different subtraction value resets stages
"2," " 4," " 8" and "16." The simultaneous counting of oscillator
pulses from oscillator 500 into counters 460 and 416 will result in
a setting of counter stage "64" on the 31st pulse. The resulting
PNY64 signal resets first escapement flip-flop 450, thereby
terminating the generation of oscillator pulses from oscillator
500. The deficit value in counter stages 418 and 420 has been
reduced by 31, thereby leaving a remaining deficit value of 23.
Counter escapement operating pulse generator 510 was never
triggered because stage CNT6 of counter stage 420 was not set. The
resetting of first escapement flip-flop 450 by PNY64 sets second
escapement flip-flop 530, thereby activating escapement oscillator
532. The oscillator pulses from oscillator 532 are counted into
counter stage 418 via OR gate 508. Eventually, counter stage 422
will overflow, as described above, thereby setting escapement
terminating flip-flop 560 and deactivating escapement oscillator
532 to terminate the escapement of the stepping motor.
The phototypesetting machine has the capability of providing the
above-described letter space compensation in one of two ways. If
letter space compensation switch 602 is in the automatic position,
lens size subtraction matrix 490 provides a different fixed
subtraction value for each of the point output size settings, 15 to
72. Table II below sets forth deficit values for the corresponding
point size outputs.
TABLE II
DEFICIT VALUES STORED IN LENS SIZE
SUBTRACTION MATRIX "AUTOMATIC MODE" Deficit Values (Three-Set)
Point Size
_________________________________________________________________________
_ 12 15 15 18 21 24 24 30 30 36 39 48 51 60 60 72
_________________________________________________________________________
_
TABLE III Multiplication No. Point Size
_________________________________________________________________________
_ 5 15 6 18 8 24 10 30 12 36 16 48 20 60 24 72
_________________________________________________________________________
_
Table III lists the point size outputs and their preferred
multiplication values in accordance with the invention. As
described above, these multiplication values are stored in lens
multiplier matrix 498.
If letter space compensation switch 602 is set into the manual
position, the operator may select the lens size subtraction value
by means of six switches on control panel 28 (FIG. 1). As indicated
in FIG. 14, these switches carry the binary designations "1," " 2,"
" 4," " 8," " 16" and "32". Thus, the operator may select any lens
size subtraction value from "0" to "63."
If the letter space compensation switch 602 is set into the "off"
position, no letter space compensation is provided and the
phototypesetting machine will escape strictly in accordance with
the escapement value set into stage 422 from lens multiplier matrix
498.
SPACE CODE AND CONTROL FUNCTION CODE OPERATION Control Function
Code
The depression of a control function key, such as upper case, lower
case, upper magazine, lower magazine, does not require activation
of either the flash or escapement circuits. Any of these four codes
will produce a negative control function pulse from keyboard
decoder 404, which thereby prevents flash flip-flop 406 from
turning on and resets LKOUT flip-flop 402 at the end of the
aforedescribed LKP pulse to end the operation of the computer for
such a control function key. The function code signals set
appropriate control circuits, for example, such as flip-flops 442
and 444 to indicate upper case and upper magazine functions,
respectively. Space Code
The generation of a space code will only provide width escapement
and not set FLASH flip-flop 406, because of the negative space code
pulse output from keyboard decoder 404. Keyboard decoder 404
generates a width value for width register 476 via six-channel
switch 474 in accordance with the width value of a particular space
code. Table IV shows the width value in three-set units for the
corresponding space code.
TABLE IV SPACE CODE SC THREE-SET VALUES
_________________________________________________________________________
_ EN 27 EM 54 THIN 18 SB 18 OSP 3 BSP 3
_________________________________________________________________________
_
the depression of a space code key on keyboard 26 activates LKOUT
flip-flop 402, and decoder 404 provides space code signal SC, both
of which set first escapement flip-flop 450 to generate ECP and
ELP, thereby clearing and loading counter 416 with the width
information stored in width register 476. First escapement
flip-flop 450 is reset with the leading edge of the first pulse
from oscillator 500. Space codes are therefore not subjected to the
above-described lens size compensation operations. Second
escapement flip-flop 530 is set to activate oscillator 532 to
escape the oscillator in a manner similar to that described above
with reference to the "off" position of lens compensation switch
602.
MISCELLANEOUS SWITCH FUNCTIONS
Film feed "end-of-take" switch 600 operates second speed-up
oscillator 532 to produce motor driver pulses through motor drivers
534 and 536 thereby advancing the film in paper advance assembly
34, as long as the switch is depressed.
Prime switch 606 resets all the flip-flops in the computer to
enable its proper operation when power is first applied to the
phototypesetting machine. Repeat FLASH switch 610, on control panel
28, holds the key release circuit energized and sets LKOUT
flip-flop 402 for every delay pulse generated by amplifier and
delay circuit 408 in accordance with the sensed timing marks on the
drums. Indicators 612 and 614, respectively, provide a visual
display for the information in width register 476 and lens multiply
matrix 498.
MODIFICATIONS OF THE PHOTOTYPESETTING MACHINE Increased Keyboard
Input
The operating speed of the phototypesetting machine may be
increased by providing a buffer memory to retain the codes
generated by a plurality of depressed keys on the keyboard, thereby
obviating the need for the operator to sometimes pause until the
end of the strobe signal on line 400, which signal unlocks the
keyboard to enable another entry. Such a buffer may, for example,
have the capability of storing eight character codes and may also
include a warning circuit to indicate to the operator that the
buffer memory is approaching saturation. In such an instance, the
operator, on hearing the alarm, would momentarily pause to avoid
saturating the memory, which might result in a failure of the
phototypesetting machine to print those characters whose keys had
been depressed but whose information was not stored in the buffer
memory. Non-Duplex Font Strip Operation
The phototypesetting machine may be modified to provide an
appropriate indication to the computer circuitry of the position of
font drum 40 when the non-duplex font strips, illustrated in FIG.
6B, are used. As described above, the non-duplex font strips have
two sets of character width information, each set corresponding,
respectively, to adjacent characters in the lower and upper rails.
In such an instance, the computer must be informed of which set of
character width values to read. Such an indication may be provided
by mounting a two-position switch to sense either of the two
positions in which font drum 40 is placed. Such a switch is
indicated as switch 93 on FIGS. 1 and 2. The lower rail position of
switch 93 would connect the escapement clear pulse to width
register 476 to transfer the information therein to the
above-described counter stages. The upper rail position of switch
93 would connect the escapement clear pulse through an appropriate
delay circuit to width register 476. The delay is necessary since
the width information for an upper rail character is reused
immediately after the data for a lower rail character (FIG.
6b).
COMPUTER CIRCUIT COMPONENTS
A detailed description of the individual components of the computer
and control circuitry as disclosed in FIGS. 13 and 14 is not
considered necessary since each of those components is known to
those skilled in the art to which this invention relates. The
necessary components described in these Figures are defined by the
aforedescribed functions and operations which they perform.
Briefly, keyboard decoder 404, lens size subtraction matrix 490,
and lens multiplier matrix 498 may preferably comprise diode
matrices. Timing marking amplifier 408 and photo-unit amplifier 410
are discrete amplifiers. Multiplexer switch 474 must have the
capability of multiplexing the width data for non-function codes or
the width information from photo-unit amplifier 410 to respective
inputs of width register 476. Speed-up oscillators 500, 532 provide
a rectangular wave output at a repetition frequency of 3,000 Hz.
Preferably, speed-up oscillator 532 (and, for the sake of reducing
the number of different circuit components, speed-up oscillator
500) produces several pulses with intermediate delays therebetween
before oscillating at its indicated frequency. This provides for
desired initial pulsing of escapement motor 286 to enable it to
respond quickly from a given rest position. Counters 416 and 460
are of a type which store a complement value and are filled-up by
successive application of pulses to the initial stage of each
counter; the overflow from one stage to a successive stage rippling
through each counter stage. Motor driver flip-flops 534 and 536 are
interconnected in a manner to provide a divide-by-three circuit,
which construction is well known to those skilled in the art. Motor
supply switch 542 comprises gates which are triggered so as to
provide pulses to stepper motor 286 which are minus 40 volts for
500 microseconds and minus 12 volts for the remainder of the pulse.
The various flip-flops, delay circuits, OR gates, AND gates,
drivers, etc. are well known to those skilled in the art and
require no additional structural definition to enable the computer
and control circuitry to function as described herein.
CONTROL PANEL SWITCHES AND INDICATOR LIGHTS
FIG. 1 discloses the layout of the various switches and indicator
lights on control panel 28. Three-position selector switch 602 is
manually operated to either one of three positions to provide for
no letter space compensation (Off position), automatic letterspace
compensation wherein values stored in lettersize subtraction matrix
490 are transferred to counter 460, or a manual position in which a
value may be inserted into subtraction matrix 490 by means of
switches 662. The numeral designations "1," " 2," " 4," " 8," " 16"
and "32," respectively, indicate the binary value inserted in
matrix 490 by activation of an associated switch. Prime pushbutton
switch 606 is depressed each time the machine is initially
activated by on/off switch 658 in order to condition the computer
and control circuitry for operation. Power indicator light 656
indicates when the machine is "On"; no film indicator light 600
indicates when no film is present in paper advance assembly 34;
shift indicator light 650 is lighted when the "shift" key on
keyboard 26 is depressed; and upper magazine indicator light 652 is
lighted when the "upper magazine" key is depressed on keyboard 26
to indicate to the operator whether he is selecting characters from
the upper magazine of font drum 40. When the cover is on the
machine "upper rail" and "lower rail" designations are provided to
indicate the position of lever 110 (as best seen in FIGS. 1 and
2).
KEYBOARD INTERLOCK
As mentioned hereinbefore, the depression of a key on keyboard 26
causes all other keys to be interlocked so that no other key can be
depressed until the phototypesetting machine has completed the
necessary escapement of the paper or film in paper advance assembly
34 in position to receive a successive character image. Such an
interlock may comprise an electromagnet which is positioned so that
its flux causes a magnetic primary member to be moved, thereby
causing interlock arms connected to the primary member to engage
the key link arms to prevent depression of their respective keys.
The magnet is deactivated when the phototypesetting machine has
completed its operation by removal of strobe signal 400 previously
described. However, use of the "Increased Keyboard Input" described
above under "Modifications of the Phototypesetting Machine"
eliminate the need for any keyboard interlock mechanism.
* * * * *