US3896454A

US3896454A - Phototypesetting machine

Info

Publication number: US3896454A
Application number: US446488A
Authority: US
Inventors: Harry L Hosterman
Original assignee: Portage Newspaper Supply Co
Current assignee: R F BELTER Corp A OH CORP; Portage Newspaper Supply Co
Priority date: 1971-08-16
Filing date: 1974-02-27
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22

Abstract

The invention disclosed is a machine for projecting letters and other characters onto a strip of photographic material to form headlines and the like. The machine includes a disc having a number of concentric ring or fonts of characters which is spun at a constant high speed, a strobe light mounted on the opposite side of the disc from the paper and energized by a control circuit to project a desired character onto the paper, and a lens system for focusing the projected image. The disc and strobe assembly are slidably toward and away from the paper to vary the size of the image projected and, through a cam, move the lens to maintain proper focusing. A novel mounting arrangement maintains the optical center of the lens on the line from a reference point on the paper to a reference point on the letter to be projected so that a uniform horizontal reference line and uniform letter spacing are maintained regardless of the size of the letters projected. Vertical shifting of the font disc relative to the strobe light and the lens selects the particular font of characters to be projected. A paper drive system is incorporated to advance the paper a distance proportional to the size of the letter projected.

Description

O United States Patent 91 1 3,896,454

Hosterman July 22, 1975 PHOTOTYPESETTING MACHINE letters and other characters onto a strip of photo- [75] inventor: Barry Hosterman Akron Ohio graphic material to form headlines and the like. The

machine includesadisc having a number of concen- [73] Assigneei Portage Newspaper pp y tric ring or fonts of characters which is spun at a cono Ohio stant high speed, a strobe light mounted on the oppo- [22] Filed: Feb 27, 1974 site side of the disc from the paper and energized by a control circuit to project a desired character onto the PP N05 446,488 paper, and a lens system for focusing the projected im- Related Application Data age. The disc and strobe assembly are slidably toward Division of Set N0 171 941 g 16 1971 and away from the paper to vary the size of the image pro ected and, through a cam, move the lens to mamtain proper focusing. A novel mounting arrangement [52] U.S. Cl. 354/ maintains the optical center of the lens on the line [51] Int. Cl B41b 15/08 from a reference vpoint on the paper to a reference [58] Field of Search 354/7, 15 point on the letter to be projected so that a uniform horizontal reference line and uniform letter spacing [56] References cued are maintained regardless of the size of the letters pro- UNITED STATES PATENTS jected. Vertical shifting of the font disc relative to the 2,714,843 8/1955 Hooven 354/7 strobe light and the lens selects the particular font of 3,485,150 12/1969 Tortorici 354/15 characters to be projected, A paper drive system is in- Primary Examiner-John M. Horan Attorney, Agent, or FirmOldham & Oldham Co.

[57] ABSTRACT The invention disclosed is a machine for projecting corporated to advance the paper a distance proportional to the size of the letter projected.

2 Claims, 17 Drawing Figures l4 so 2 6 26 24 '7 I6 26 2s 22 s4 l8 k 58 98 l 32 54 [*f l58 -so 32 I49 [i l56 34 I 5 I62 36 E I I t\\\ -ATYZ 4 4O 3 38 4 1 i I V////////////////////Ai ea 1:38 we I86 1'92 E- 2 one Foc'AL LENGTH ONE FOCAL LENGTH Y PATENTEDJULQZ 3,896,454

SHEET 3 ZIZ ONE 2|2 FOCAL I90 I48 LENGTH 32 I as l l 3 ONE I74 2|0 4 FOCAL 204 I46 LENGTH I58 I6 I66 1 I86 W k y IZ/ lB( III I96 l 84 FIG.5

PATENTEDJUL 22 ms FIG. I?)

PATENTEDJUL 22 1915 II II I! II II I,

NINE j 111 Hi In A u HI I\\ y;

FIG. ll

PATENIEDJPLQZ ms 3,896,454

' SHEET 7 3|O me I 304 I2 PATENTED JUL 2 2 1915 2 H L EA N6 00 F 0 L ow R 6 H mm LH m O MAT 66 m L T4 N n w m NW6 T AR L R mm D 0 ONE FOCAL PLANE oF- PHOTOPAPER LENGTH FIG. I?

PHOTOTYPESETTING MACHINE This is a division of application Ser. No. 171,941, filed Aug. 16, 1971.

This invention relates to a phototypesetting machine for projecting a series of letters or other indicia onto a strip of photographic material to form headlines or the like and more particularly to a phototypesetting machine for projecting a letter or other indicia in the form of a negative image on a plastic sheet or disc onto a sheet of photographic paper.

The general system of phototypesetting by projecting individual characters onto a photographic sheet from a rapidly moving negative master by the action of a strobe light is well known in the art. However, prior phototypesetting machines have certain defects which render them difficult to use and which heretofore have been overcome only by complicated and expensivearrangements. Among these defects is the difficulty in maintaining a sharp focus of the projected image on the photographic paper strip when the size of the projected image is varied. It is common practice to provide a turret lens arrangement so that different lenses are used for different sized images. In such an arrangement, one lens is provided for each projected image size desired. The number of possible image sizes is thus limited and can be increased only by increasing the number of lens provided and consequently, the cost and complexity of the phototypesetting machine.

In any phototypesetting equipment in which the projected image size can be varied, provision must be made for varying the amount of photographic material advanced after each image is projected so that uniform letter spacing can be maintained. While the prior phototypesetting machines do include paper feed mechanisms which accomplish uniform letter spacing, the control of the feed mechanism is not fully automatic but must be adjusted manually whenever the projected image size is changed. Also, the paper feed mechanism of the prior machines are not capable of operating accurately at high speeds and thus limit the speed at which a line of type can be generated to a level considerably below the capability of the machine operator.

It is the primary object of the present invention to provide a phototypesetting machine in which a single lens system is employed and in which the lens is always maintained in a position relative to the image bearing disc and the photographic paper so that a clear and sharp image is focused on the paper, regardless of the size of the image being projected.

It is also an object of the present invention to provide a phototypesetting machine which all the images are projected onto a uniform horizontal reference line and reference point, regardless of the size of the image or the font from which the image is selected.

A further object of the invention is the provision of a phototypesetting machine in which the spacing of the letters on the photographic material is proportional throughout the length of the line of characters projected.

A still further object of the invention is the provision of a phototypesetting machine which is of simpler and more economic construction than the machines of the prior art.

Among other objects of the invention is the provision of a phototypesetting machine which has a photographic material advancing mechanism capable of maintaining proportional letter spacing automatically in accordance with the size of the image projected and which is capable of high speed operation.

Another object of the invention is the provision in a phototypesetting machine of a photographic material advancing mechanism which automatically withdraws the paper or other photographic material from a supply magazine, advances the paper along a plane onto which letter images are projected, and stores the exposed paper in a second magazine.

The above and other objects of the invention which will become apparent in the following detailed description are achieved by providing a phototypesetting machine which employs a lens system mounted in sliding relation to the font bearing disc and moved by a cam in response to movement of the disc carrying subassembly so that the lens is maintained at the proper focal point for any separation between the photographic paper or other material and the font disc and, thus, for any size of image projected onto the paper. The lens system is vertically and horizontally positioned by a rod which maintains the optical center of the lens on a line extending from a reference point in the plane of the photographic paper to a reference point on the circle of the indicia being projected so that all indicia is projected onto a common line. The font disc is vertically shifted to change from one font of type to another. The machine also includes a paper feed arrangement which compensates for any error in letter spacing due to the delay in mechanical movement of the feed control members to assure uniform spacing of the projected characters.

For a more complete understanding of the invention and the objects and advantages thereof reference should be had to the following specification and the accompanying drawings wherein there is shown a preferred embodiment of the invention.

In the drawing:

FIG. 1 is a side elevational view of the phototypesetting machine of the present invention, with portions of the assembly removed for clarity;

FIG. 2 is a vertical section taken along the line 2-2 of FIG. 1 and showing the front elevation of the font assembly;

FIG. 3 is a vertical section taken along the line 3-3 of FIG. 1 and showing therear elevation of the font assembly;

FIG. 4 is a transverse sectional view taken along the line 4-4 of FIG. 1',

FIG. 5 is a vertical sectional view taken along the line 55 of FIG. 1 and showing the lens carriage assembly;

FIG. 6 is a fragmentary sectional view taken along the line 6-6 of FIG. 3;

FIG. 7 is an elevational view of the font disc employed in the assembly of the present invention;

FIG. 8 is a fragmentary vertical section taken along the line 88 of FIG. 4;

FIG. 9 is a plan view of the paper feed subassembly;

FIG. 10 is a fragmentary sectional view taken along the line 10-10 of FIG. 9 and showing the paper aligning rollers of the paper feed subsassembly;

FIG. 11 vis a fragmentary sectional view taken along the line 1111 of FIG. 9 and showing the take-up reel of the paper feed subassembly;

FIG. 12 is a schematic diagram of the control circuits of the phototypesetting machine;

FIG. 13 is a schematic diagram of the upper-lower case and font shift control circuits;

FIG. 14 is a vertical sectional view taken along the optical axis of the phototypesetting machine and showing a modified form of the invention in which the projected character is visible to the machine operator;

FIG. 15 is an isometric view of the assembled phototypesetting machine;

FIG. 16 is a fragmentary elevational view showing, in a schematic manner, the mounting arrangement for the lens position control rod; and

FIG. 17 is a diagrammatic view illustrating the relative positions of the font disc, lens, and photosensitive paper for the projection of various sizes of images.

As will be seen from FIG. 1, the phototypesetting machine 10 consists of a base 12 on which are supported an image projecting subassembly 14, a lens subassembly l6, and a photographic paper feed subassembly 18. The image projecting subassembly 14 consists, basically, of a disc 20 which carries concentric rings of negative images of type characters and encoded identification data, a motor 22 for rotating the disc 20 at a constant speed, a first lamp or lamps 24, a cylindrical lens 25 for directing the light from lamp 24 in a narrow beam, and photodiode arrays or

other sensing devices

26 and 28 for detecting the encoded data, and a strobe light 30 controlled by a firing circuit to project an image of an individual character. The first lamp 24 illuminates the identifying letter width data carried on the font disc 20 so that the data can be sensed by the

devices

26 and 28. Preferably, a red filter 64 covers the lamp 24 so that the light from this lamp does not effect the photographic paper. While specific reference is made to the use of photographic paper, other photographic materials such as film may also be used. The term paper when used in this specification and claims is intended to encompass such materials.

The firing of the strobe light 30 occurs when the desired image is aligned with the light 30 and the lens of the lens assembly 16. The image is thus projected onto a sheet of photosensitive paper 32 which is then advanced in proportion to the width of the projected image to move an unexposed portion of the paper 32 to receive the next image to be projected. The size of the image projected is varied by moving the font disc and strobe subassembly 14 toward or away from the plane of the paper 32. Obviously, the lens assembly 16 must also be moved to maintain sharp focusing of the image projected on the paper 32. As will be discussed in more detail below, the positioning of the lens assembly 16 is accomplished by a cam arrangement which assures that the lens is in the proper relationship to the disc 20 and to the paper 32 at all times. In order that the words generated on the paper 32 by the projection of successive images may have a common reference line, it is necessary that the projected images all meet a common reference point. As will be discussed in more detail below, this is achieved by a novel aligning arrangement which maintains the center of the lens of the assembly 16 on the optical center line passing through a reference point fixed in the plane of the paper 32 and a reference point on the image carried on the disc 20.

FONT DISC SUBASSEMBLY The subassembly 14 is illustrated in FIGS. 1-4. The subassembly is supported by a carriage 34 which is supported on one of its side by a rod 36 connected to the base 12 by suitable brackets 38. Bushings 40 permit the carriage 34 to slide along the rod 36. The opposite side of the carriage is supported by a roller 42 running on a track 44 also mounted on the base 12. Extending upwardly from the carriage 34 are tworods 46 and 48. A subframe 50 is slidably received on the

rods

46 and 48 and this subframe carries the font wheel drive motor. 22 together with the font wheel 20. A disc 52 connected to the motor shaft 54 supports the font disc and a second disc 56 rotatably carried on an arm 58 engages the opposite face of the font disc. A hinge connection 60 connects the arm 58 to upwardly projecting portion 62 of the vertical subframe 50. The hinge joint 60 is an overcenter spring loaded joint. The two

information detecting devices

26 and 28 are carried on the arm 58.

The subframe 50 is shifted vertically on the

rods

46 and 48 by a shifting assembly consisting of the two

shift wheel assemblies

66 and 68 and the adjustable con necting link 95. This assembly is illustrated in FIGS. 2, 3, and 6. The upper shift wheel assembly 66 is carried by a plate 70 connected to the subframe 50. The upper shift wheel 72 is journalled on this plate 70. The wheel 72 has a pair of diametrically opposed notches 74 and 74a which cooperate with a pawl 76 carried by the plate 70 to permit 180 rotation of the upper shift wheel 72. The lower shift wheel assembly 68 includes a plate 82 which is mounted to the carriage 34. The lower shift wheel 84 is journalled on this plate in vertical alignment with the upper shift wheel 72. The lower shift wheel 94 is also provided with a pair of diametrically

opposed notches

86 and 86a and a pawl 88 carried by the plate 82 permits 180 rotation of the lower shift wheel 84. A length adjustable link 95 is connected at one end to the lower shift wheel by a radially adjustable pin 94 at its opposite end to the upper shift wheel by a pin 96. The distance between the pin 94 and the center of the lower shift disc 84 is one half the distance between the radially adjustable pin 96 and the center of the upper shift disc 72.

The upper shift wheel 72 and lower shift wheel 84 are connected to

pulleys

102 and 104, respectively, through magnetic clutches. The magnetic clutch 114 of the lower shift wheel 84 is illustrated in FIG. 6. As will be seen from FIG. 3, the motor 22 is provided with a pulley 98 which drives a belt 101 which is entrained over both of the shift wheel pulleys 102 and 104. The belt 101 is also entrained over an idler pulley 110 carried on the carriage 34 and vertically aligned with the motor pulley 98 and over additional

idler pulleys

106 and 108 journalled on a bracket 112 which is carried on the carriage 34. The pulley 106 is located so that the belt 101 travels a vertical path downwardly from the pulley 106 to the upper shift wheel pulley 102. This arrangement provides a constant length belt path when the subframe 50 is shifted vertically. When the subframe is moved vertically upwardly the length of the belt path between the pulley 106 and the upper shift wheel pulley 102 decreases by an amount equal to the increase in path length between the motor pulley 98 and the carriage mounted idler pulley 110.

The shift wheels may be controlled by the circuit shown in FIG. 13. Eachof the

wheels

72 and 84 is provided with a

small Alnico magnet

81 and 93, respectively. A pair of

reed switches

78 and and and 92, respectively, are mounted closely adjacent the

wheels

72 and 84 at diametrically opposite points on the circumference of the respective wheel. The reed switches are positioned in relation to the magnet so that one or .the other of the reed switches is aligned with the magnet when the respective shift wheel is held fixed by its associated

pawl

76 or 88. FIG. 13 illustrates the clutch control circuit for the lower shift assembly. It will be understood that the upper shift wheel assembly is controlled by a similar circuit. The solenoid of the clutch 114 is connected through a' transistor 116 to a positive DC voltage source. The collector of the transistor 116 is also connected to ground through the reed switches 90 and 92 connected in parallel and through a toggle switch 118 in series with the reed switches. When the toggle switch 118 is in the position shown in FIG. 13, the circuit through the reed switches and the toggle switch is open. As a result, the transistor 1 16 conducts and the solenoid 114 is energized. The clutch is engaged and the shift wheel 84 is now turned. As the magnet 93 approaches the reed switch 92 it will cause this switch to close completing a ground circuit to the collector of the transistor 116 through the reed switch 92 and the toggle switch 118. This ground circuit will bias the transistor 1 16 off, deenergizing the clutch 114. The pawl 88 now engages the notch 86 of the wheel 84 and holds the wheel in position until the toggle switch position is reversed to again remove the ground circuit from the collector of the transistor 116.

The font disc is illustrated in FIG. 7. The disc is circular and has a central mounting hole 124. Alphabetic characters or other indicia 126 are arranged in concentric circles 126a-126d on the disc. Preferably each of the circles or rings 126a-126d consists of one complete set of characters of a single type style. In the embodiment shown, the outer most ring 126a consists of a complete set of capital italic letters; the ring 126b, of capital Roman letters; and the

inner rings

126a and 126d of lower case italic and Roman letters, respectively. The characters of the rings are aligned so that each character in each ring is radially aligned with the same characters of the other rings. Each character 126 is identified by a number expressed in binary code and this information is carried in a ring 128 on the disc 20 with the binary number for each character being located 180 from its associated character. The disc 20 also carries four rings 130a-l30d of marks which are associated with the characters located 180 from the respectivemarks and which indicate the width of the vided for each character on the disc and these marks lead the width indicating marks 130a-d.

The vertical shifting of the subframe 50 by means of the

shift wheel assemblies

66 and 68 in the manner described above shifts the disc 20 vertically relative to the strobe light 30 and a line from the plane of the photographic paper 32 through the center of the lens of the assembly 16 to bring one or the other of the circles of characters 126a-126d into alignment with the light 30 and the projection line. A 180 rotation of the upper shift wheel 72 moves the font disc 20 a distance equal to two of the rings of characters and thus effects a shift between the upper and lower cases of the same font style. A 180 rotation of the lower shift wheel 84 moves the font disc 20 a distance equal to one ring of characters and thus effects a shift between the two font styles.

Movement of the carriage 34 and the font disc assembly 14 forwardly and rearwardly along the bar 36 and track 44 is accomplished by the linkage arrangement illustrated in FIG. 8. A crank wheel 132 is connected by a crank rod 134 to an adjustable length bracket 136 respective characters. A pulse mark 131 is also proattached to the font assembly carriage 34. The wheel 132 is fixed to a shaft 138 which is journalled on suitable brackets connected to the main frame 12. A bevel gear 140 is also secured to the shaft and engages a mating bevel gear 142 which is affixed to one end of a shaft 144 extending to a control knob 146. Since the link 134 is connected to the wheel 132 in an off center relation, rotation of the wheel 132 will move the carriage 34 forwardly or rearwardly. A rheostat or variable resistor 288 is also connected to the shaft 138 and, as will be described below, furnishes a control signal proportional to the size of the projected image.

LENS TRANSPORT ASSEMBLY The lens transport assembly is shown in FIGS. 1, 4, and 5. The transport assembly 16 includes a transport carriage 148 which is slidably supported on the rod 36 by a bushing 150 and on the track 44 by roller 152 carried at the end of an arm 154. Secured to an upwardly projecting portion 149 of the carriage 148 by a pivot pin 156 is a vertical link 158. An upper horizontal link 160 is pivotally connected at one end to the upper end of the vertical link 158 and a lower horizontal link 162 is pivotally connected at an intermediate point to the lower end of the vertical link 158 and the lens holding assembly 164 is pivotally connected to the opposite end of the upper link 160 and to one end of the lower link 162. The lens assembly 164 mounts a lens 166. The lower arm 162 extends on the opposite side of the vertical link 158 and is provided at its second end with a ball joint 168 which slidably receives a rod 170. The rod 170 projects rearwardly and is slidably received in a ball joint 172 supported by the carriage 34 of the font assembly 14. Preferably, the ball joint 172 is connected to the carriage 34 by an adjustable mounting 173 which permits the ball joint to be shifted vertically between lower and upper positions separated by the height of a character on the disc. As will become apparent below, this arrangement permits either the upper or lower edge of the letter to be selected as the reference point. One possible adjustable mounting for this purpose is shown in FIG. 16. The ball joint 172 is carried on an arm 175 which slides vertically in a bracket 187 affixed to the carriage 34. An eccentric disc 177 contacts the arm 175 to determine its height. Rotating with the eccentric 177 is a second disc 179 which is provided with diametrically opposed notches 181. A pawl 183 carried by the bracket 187 engages one of the notches 181 to previsely locate the disc 179 and eccentric 177. A spring biases the arm 175 downwardly to maintain the arm in firm contact with the eccentric 177. It will be understood, of course, that other arrangements for achieving the vertical adjustability of the ball joint 172 may be used in placeof that described.

The rod 170 also projects forwardly through the ball joint 168 to a ball joint 184 which is carried in a bracket 176 affixed to the main frame 12. The bracket 176 may be adjustable to permit the reference line to be shifted on the photosensitive paper. The centers of the ball joints 172 and 174 are located in the planes of the font disc and the photographic paper, respectively.

As will be seen from FIG. 5, the linkage arrangement 158-164 provides a parallelogram arrangement by which the lens 166 is moved exactly opposite to the movement of the ball joint 168 at the end of the lower link arm 162. Thus, as the arm 162 moves to the right the lens moves to the left, and, as the ball joint 168 moves upwardly the lens 166 moves downwardly. It will be noted that the control rod 170 is angled relative to the support rod 36 and that the angle of the rod 170 changes as the font carriage 34 is moved toward or away from the plane of the photographic paper 32. The arm 170 is so oriented that the optical center of the lens 166 remains on a line passing from a reference point on the plane of the photographic paper 32 to a reference point on the font disc 20, regardless of the position of the font disc relative to the plane of the photographic paper 32.

Control of the position of the lens carriage 148 is achieved by a cam arrangement illustrated most clearly in FIG. 4. A cam 178 which has straight cam surfaces 180 and 182 extending at right angles to one another and a lug 184 extending from the intersection of the cam surfaces 180 and 182 at equal angles thereto is pivotally connected to a downwardly projecting leg 186 of the lens transport carriage 148. The first cam surface 180 of the cam member 178 bears against a roller 188 which is mounted on a bracket 190 secured to the main base 1.2. The second cam surface 182 bears against a roller 192 which is carried by a bracket 194 depending from the font assembly carriage 34. The

rollers

188 and 192 are arranged on a line parallel to the main support rod 36 and track 44. The fixed roller 188 is fixed relative to the plane of the photographic paper 32 while the roller 192 carried by the font assembly carriage 34 is on a line extending parallel to the main support rod 36 and passing through the center of the fixed roller 188. The center of the fixed roller 188 is located one focal length of the lens 166 rearwardly of the plane of the photographic paper and the center of the roller 192 is located on focal length forwardly of the plane of the font disc. The axis of the pivotal connection between the cam 178 and the downwardly projecting leg 186 is located at the intersection of a line parallel to the cam surface 180 and passing through the center of the roller 188 and a line parallel to the cam surface 182 and passing through the center of the roller 192. This axis is one focal length from the line joining the centers of the

rollers

188 and 192.

It will be seen that as the font assembly carriage 34 is moved toward the plane 32 of the photographic paper the cam will be forced forwardly and rotated so that the lens transport carriage 148 is also moved forwardly but at a rate varying with the position of the carriage 34 relative to the plane of the photographic film 32 and the lens 166 is always maintained in position so that the lens is in proper focus. When the cam 178 is in its middle position, that is, when both of the cam surfaces 180 and 182 form 45 angles with the direction of movement of the font assembly carriage 34, there is an ambiguity of movement since the cam may turn in either direction upon further movement of the carriage 34. The assembly shown in FIGS. 4 and 8 is provided to resolve this ambiguity and assure that the cam 178 moves in the proper direction moving the lens 166 also in the proper direction. The assembly consists of an arm 196 projecting from the lens carriage 184 and mounting a roller 198 which is spring biased as indicated at 200 to engage a notch 202 in a sliding member 204. The sliding member is received in suitable support blocks 206 and 208 connected to the main frame 12 with the sliding member 204 extending parallel to the main support rod 36. Pulleys 210 are provided at the opposite ends of the slide rod 204 and an endless belt 212 extends around the crank wheel 132 and the pulleys 210 with the belt being anchored to the crank wheel at 214 and to the font assembly carriage 34, as indicated at. 216. It will be seen that the slide bar 204 will move forwardly or rearwardly depending on the direction of rotation of the eccentric wheel 132. When the cam member 178 is in its mid position the roller 198 will engage the bottom of the notch 202 of the sliding member 204. The direction of movement of the sliding bar 204 is the same as the direction of movement circumference of drive wheel 132 so that during this interval the lens transport carriage 148 is moved by the action of the slide bar 204 acting on the roller 98. When the cam member 178 has passed through its cen' ter position the roller 198 moves up on the side of the notch 202. Thus, the notch 202 serves as a centering means to assure proper positioning of the lens when the cam is in its center position, as a means for causing the cam member 178 to move in the proper direction when the cam member 178 moves through its central or neutral position, and as a means to apply a spring force to keep the cam member 178 against the

roll

188 and 192. The action of the cam 178 can be clearly seen in FIG. 17 where the relative positions of the font disc 20, lens 166 and photographic paper 32 for projecting the largest, smallest, and unenlarged images are shown. These positions are indicated respectively, in solid, dashed, and dash-dot lines. The relative positions of the points of contact between the

rollers

188 and 192 and the camming surfaces 180 and 182, respectively, and the pivot point of the connection 184 are also shown for the corresponding positions. FIG. 17 also illustrates the action of the lens positioning rod 172 which serves to maintain the projected images on a common reference line and with their leading edges at a common reference point. In the arrangement shown, all the characters are projected to a common reference point R, which corresponds to the lower left edge of the character. Since the photographic paper 32 faces toward the lens and font disc, the projected characters when viewed as in FIG. 17 are mirror images and the reference point R, appears to be at the lower right corner. This, however is the leading edge of the letter. In order to achieve this uniformity, the center of the lens 166 remains on the line from the reference point R to the corresponding point R or the font disc.

PAPER FEED ASSEMBLY The paper feed assembly is illustrated in FIGS. 9-11. The assembly includes a support platform 218. A paper feed magazine 220 supplies unexposed photographic paper which is entrained over an idler roller 222, a first drive roller 224, through a guide plate assembly 226 to a second drive roller 230 and an encoder roller 232 to a takeup magazine 236. The guide plate assembly 226 comprises a fixed back plate 217 which is mounted in the support platform 218 and a pair of

font plates

219 and 221 which are spaced from the back plate 217 to provide a slot 223 through which the photographic material is passed. A window 228 is provided between the

front plates

219 and 221 to expose a short section of the photographic paper. The front plate 221 at the exit end of the slot 223 is rigidly mounted on the support platform 218 while the front plate 219 is pivotally connected to the support platform 218 by a pin 231. A rod 233 normally holds the plate 219 in parallel, closely spaced relation to the back plate 217, A spring 235 carried by the plate 219 contacts the forward edge of the support platform 218 and biases the plate 219 away from the back plate 217 when the rod 233 is shifted away from the plate 217. As will be described more fully below, this arrangement permits automatic threading of a new strip of photographic paper.

A paper brake is carried on the back plate 217 and includes a brake plate 225 which is normally biased toward the front plate 219 to clamp the photographic paper against the frontplate 219. A voice coil type electromagnetic 227 that is, an electromagnet which is capable of positive movement in both the forward and reverse directions, is connected to the brake plate 225.

In addition, a spring 239 may also be provided to bias the brake plate toward the front plate 219. The operation of the paper brake will be described below.

The back plate 217 also carries a pair of aligning rollers 237, 237a which engage the upper and lower edges, respectively, of the photographic paper. As will be seen from FIG. 10, the rollers 237, 237a are guided by ,a vertical slot 241 in the back plate 217 and connected by a linkage arrangement 242 to a solenoid 243. The linkage arrangement 242 is such that the rollers 237, 237a move equal amounts in opposite directions.

This assures that the horizontal centerline of the photo-' graphic paper will remain at a fixed height above the support platform 218 regardless of the width of the paper.

The takeup magazine 236 is illustrated in FIGS. 9 and 11. The magazine has a casing-253 which is provided with an opening 244 for receiving the paper as it is passed from the drive roller 230 and the encoder roller 236. The casing 253 may be formed of transparent red plastic so that the contents of the magazine can be viewed while the exposed paper is protected from light. A wind up spool 240 is provided in the center of the enclosure 253 and is attached to a magnetically attractable disc 247. A permanent magnet disc 248 is located immediately below the disc 247 and is attached by a pully 249 driven, through a belt, by a motor 234. The supply magazine 236 is provided with a plurality of inwardly projecting spring fingers 238 which direct the incoming strip of paper toward the wind up spool 240. The surface of the spool 240 may be provided with a rubber or other friction facing to grip the incoming paper. The opening 244 of the enclosure 253 is provided with a shutter 245 to form a light-tight seal of the opening. A pin 246 mounted on the support base 218 engages the shutter when the magazine is'properly positioned to hole the shutter 245 open. A manually operated knife may be provided adjacent the opening 244 of the magazine to cut the length of photographic paper. Preferably, means are provided in conjunction with the knife 25] to stop rotation of the wind up spool 240 when the paper is cut to leave a short length of paper protruding from the opening 244 so that the paper may be withdrawn from the magazine for processing.

A suitable motor 234 drives the first drive roll 224, the second drive roll 230, and the winding spool 240 of the takeup magazine 236. The first idler roll 222 is movable by means of a solenoid (not shown) to be brought into andout of engagement with the first drive roll 224. This solenoid may alsocontrol the position of the rod (notshown) 233 which holds the front plate 219 in parallel relation to the back plate 217. Likewise, the encoder ml] 232 is controlled by a spring 232a.

The first idler roll 22 is brought into contact with the first drive roll 224 only during the initial threading of paper through the paper feed mechanism. At this time the brake plate 225 is fully retracted by the electromagnet 227, the rod 233 is shifted to its outer position permitting the front plate 219 to pivot away from the back plate 217 into the position shown in dotted outline in FIG. 9, and the guide rollers 237 and 237a are moved to their uppermost and lowermost position, respectively. The leading edge of the paper strip can now be threaded manually from the supply magazine to the bite between the idler roll 222 and the first drive roll 224. The paper is now pulled from the supply magazine 220 and fed through the slot 223 to the second drive roll 230 and to the take up magazine 236. Since the plate 219 is shifted away from the back plate 217, the paper passes freely through the slot 223.

Suitable guide plates

224a and 230a may be provided to direct the paper along the desired path. Upon completion of the threading sequence, the solenoid which moves the first idler roll 222 is deenergized to move the idler roll 222 out of contact with the first drive roll 224 and to move the rod 233 back to its normal position holding the front plate 219 parallel to the back plate 217. At the same time the guide rollers 237 and 237a are permitted to move toward one another so that the paper is properly centered horizontally. The electromagnet 227 is actuated at the same time to clamp the paper in position.

During normal operation the first idler roll 222 is spaced slightly from the first drive roll 224 so that the first drive roll is normally inoperative to move paper. The encoder roIl 232 drives an encoder of the type which generates a pulse for every fraction of a revolution of the encoder. The encoder roll 232 normally maintains pressure on the paper to hold the paper against the second drive roll 230. However, this pressure is insufficient to overcome the brake 225 so that no paper is advanced unless the brake is released. The

encoder thus operates only during the advancement of paper and provides a pulse train proportional to the amount of paper advanced. As the second drive roll 230 beings to advance the paper, the paper will tend to wrap more tightly around the first drive roll 224 and as a result, the first drive roll 224 will pull additional paper from the supply magazine 220. Preferably, the

first drive roll 224 has a higher peripheral speed than does the second drive roll 230 so that the first drive roll 224 will feed additional paper at a rate sufficient to relieve tension on the paper between the two drive rolls. This assures accurate advancement of the paper and uniform letter spacing.

CONTROL CIRCUITS FIG. 12 illustrates, schematically, the control circuit of the phototypesetting machine of the present invention. The keyboard 250 is a standard binary coded electric keyboard which furnishes a binary coded signalfor each character. When a character key of the keyboard 250 is pressed an enabling signal is supplied to a counter 254. The counter receives pulses from the flash pulse diode 256 which is one diode of the photodiode array 26. The flash pulse diode 256 is actuated by the pulse marks 131 on the font disc 20. Upon receipt of the enabling signal from the keyboard 250 the counter counts three pulses from the flash pulse diode 256 and then resets the memory 252 by erasing the previously stored information. The counter 254 continues to count pulses until five additional pulses are received, at which time the memory admits the identifying signal from the keyboard 250. The identifying code in the memory 252 is supplied to a match detector circuit 258 which is continuously receiving the identifying code of each character on the font disc from the letter code diodes 28. When a match occurs, that is when the identifying code from the keyboard 250 corresponds to the code supplied by the letter code diodes 28 a signal is sent to the gate 260. The gate 260 is an NAND gate requiring a signal from the match detector 258 and a pulse signal from the flash pulse diode 256. Upon receipt of the two signals the gate 260 energizes the single flash control circuit 262 which, in turn, energizes the flash tube electronics 264 to fire the strobe light 30. The selected character is thus projected to the photographic film. The action of the counter 254 serves to assure that the leading edge of the pulse mark 131 always determines the time of firing of the strobe light 30. If, by coincidence, a particular character key is depressed on the keyboard 250 at the same time the identifying mark 128 of the same character on font disc is being scanned by the photodiodes 26, a late triggering of the strobe light 30 would occur in the absence of the counter 254. Since the counter 254 requires a total of eight pulses to be recorded before the data code supplied by the keyboard 250 is admitted to the memory 252, and since the NAND gate 260 cannot be energized until the flash pulse from the diode 256 and the match signal occur simultaneously, late firing is avoided. The maximum delay is slightly less than one full revolution of the font disc and, as the disc 20 rotates at a high speed, this delay is minimal. The single flash control circuit 262 prevents the strobe 30 from being fired on the next and succeeding rotatations of the disc.

In addition to energizing the flash tube electronics 264, the signal from the single flash control circuit 262 is also supplied to a gate 266 which receives an input from an oscillator 268 and a control input from the length code diodes 26. The length code diodes 26 are responsive to the length indicating marks l30a-130d of v the font disc 20, the particular mark being determined by the font and case of the character being projected. The gate 266 operates to transmit pulses from the oscillator 268 to a register 270 for a length of time determined by the length code diodes 26. Thus, the signal supplied to the register 270 is a measure of the width of the projected letter. At the beginning of transmission of pulses from the oscillator 268 to the register 270 a signal is sent to the brake electromagnet 272 to release the brake. The second drive capstan 230 now begins to advance the paper and to drive the encoder carried by the encoder roll 232. The encoder 272 furnishes a series of pulses which is a measure of the amount of paper moved to the register 270 and these pulses are subtracted from the pulses supplied from the oscillator 268. When the register 270 has been brought back to zero count by the pulses from the encoder 272 the brake electromagnet 227 is again energized, stopping the paper. Due to the slight mechanical delay in operation of the brake 225 a small additional amount of paper may be advanced. Thus, the encoder 272 will continue to supply pulses to the register 270 and these pulses are stored as a negative count in the register 270 to be subtracted from the next pulse sequence supplied from the oscillator 268. This arrangement assures uniform letter spacing as it, in effect, shifts the succeeding letter by an amount equal to the overtrav'el of the paper.

The space function 274, which is normally a part of the keyboard 250 but is shown as a separate function here for clarity, actuates a pulse generator 276 which supplies an actuating pulse to the gate 266 to permit the oscillator 268 to transmit a pulse train proportional to the width of space to the register 270. Thus, the space function 274 permits the paper to advance without the firing of the strobe light. The shift and

font functions

278 and 284, respectively, energize the corresponding controls and clutches to shift the disc assembly vertically, as described above.

The size control rheostat 288 which. is described above, is controlled by the position of the font disc and lens, controls the oscillation rate of the oscillator 268 to vary the number of pulses supplied to the register 270 in accordance with the size of the projected letter. Thus, when a large size letter is being projected, the oscillator 268 operates more rapidly to supply a larger pulse count to the register 270. The size control 288 also controls the paper drive motor 234, increasing motor speed with increased projection letter size. The size control rheostat 288 further serves, through the flash tube electronic circuit 264, to control the intensity of the strobe light 30, the intensity being greater when large images are projected.

Additional control functions may also be provided. Thus, a kern control 290 may be provided to decrease the spacing between adjacent letters to produce a more uniform appearance of the line of type, for example, where an A is to follow a T. The kern control 290 is connected to the oscillator 268 to slow down the oscillator and, thereby, supply a lower pulse count to the register 270. The repeat control 292 serves to reset the single flash control circuit 262 so that the previously selected and identified character which is stored in the memory 252 is again projected. A recall function 294 can also be provided to project the last letter selected without causing the printing of this letter. The recall control function 294 actuates a solenoid 296 which moves a red shutter in front of the font disc so that only a red image is projected toward the paper, preventing the paper from being exposed. The recall function 294 also triggers the flash tube electronics 264 to project last selected character. It will be noted that the paper advance mechanism is not actuated by the recall function 294. v

A viewing arrangement for permitting the operator to see the letter projected, either when the letter is projected onto the photographic paper or by operation of the recall function 294 is merely projected for viewing. A beam splitter 300 is carried in front of the font disc 20 on the line from the strobe light through the lens 166 to the photographic material 32. The beam splitter 300 is mounted on a suitable support 302 carried by the font assembly sub-base 34 and serves to split the beam projected through the disc into a first, primary beam which is directed to the photographic film 32 and to a second beam which is directed downwardly to a prism 304 carried in a housing 306 which is also supported by the sub-base 34. The housing 306 carries a lens 308 which has infinity focus. The beam from the prism 304 through the lens 308 passes through a second lens 310 carried by the paper feed subassembly 18. The lens 310 restores the beam to a finite focus and directs it onto a first mirror 312 which in turn projects the beam to a second mirror 314 and hence to a viewing screen 318 positioned on or above keyboard 250. Because the lens 308 is at infinity focus, the length of the path between the

lens

308 and 310 has no effect on the focus of the system and no compensation is required for the variation in the distance between the front disc and the photographic paper. Each character projected to the photographic paper 32 is also projected along the second path and is visible to the operator on the viewing screen 308. When the recall function is operated the solenoid 296 moves a red shutter or filter 298 in front of the font disc so that only a red beam is projected. Since the photographic paper is insensitive to red light the paper is not exposed but the projected character is visible on the viewing screen 318.

It should now be apparent that the present invention provides a phototypesetting machine which is of less expensive and simpler construction than the machines of the prior art but which is of greater versatility than the earlier machines. The cam arrangement for moving the lens in coordination with the movement of the disc and strobe light assembly towards and away from the photographic paper eliminates the need for a multiple lens system while assuring accurate focusing throughout the entire range of projected image sizes. By the novel arrangement of the control rod maintaining the optical center of the lens on the lines through the reference point on the plane of the photographic paper and the reference point of the images on the font disc 20, the present invention assures that all characters will be projected on a uniform base line regardless of the size of the characters. The paper feed arrangement is also an advance over those of the prior art since it automatically assures uniform spacing of the letters, regardless of the size of the projected image. The electronics provides a precise control to the strobe and the movement of the paper.

It should be understood that while only the best known embodiment of the invention has been illustrated and described in detail herein, the invention is not so limited and the changes and additions may be made to the invention without departing from the spirit thereof. Reference should thus be had to the appended claims in determining the true scope of thevinvention.

What is claimed is:

1. In a phototypesetting machine having:

a mechanism for holding a sheet of photographic paper in a plane and for advancing the paper along the plane;

a disc having at least one ring of negative images of type characters and an identifying mark for each image of the ring, the disc being parallel to but spaced from the plane of the paper;

a motor for rotating the disc;

a strobe light on the opposite side of the disc from the paper;

a lens between the paper and the disc and on the optical axis from the strobe light to the paper;

a light source for illuminating the identifying marks of the disc in sequence as the disc is rotated;

photoelectric sensing means for translating the illuminated identifying marks into electrical signals;

means to select an individual character, the means producing an electrical signal identifying the selected character;

a match detector for comparing the signal produced by the photoelectric sensing means and the signal from the selecting means to indicate when the selected character corresponds to the character on the disc detected by the sensing means; and

a strobe firing circuit triggered by the match detector whereby the strobe light is tired to illuminate the selected character image of the disc and project the image through the lens to the paper, the improvement comprising:

a character width indicating mark upon the disc for each character of the ring, an additional photoelectric sensing means being provided to sense each width indicating mark and produce an electrical signal corresponding to the width of the associated character, and circuit means receiving the signal from the additional sensing means for controlling the mechanism for advancing the paper to advance the paper a distance proportional to the width of the projected character,

said circuit means including an oscillator, an arithmetic updown register, a gate controlled by the additional photoelectric sensing means for supplying a pulse train proportional in length to the character width from the oscillator to the register to cause the register to count up, and a pulse generator responsive to movement of the paper to generate a pulse train proportional in length to the amount of paper advanced, the pulse train from the pulse generator causing the register to count down, wherein the paper advancing mechanism includes a second motor, a drive capstan driven by the motor and engaging the paper to advance the same and an electromagnetically operated brake operative to engage the paper and prevent its movement, the circuit means controlling the brake, the brake being controlled by the register whereby the brake is released while the register is counting down.

2. The improvement in a phototypesetting machine as recited in claim 1 wherein the disc and lens are movable toward and away from the paper to vary the size of the image projected on the paper and are interconnected with means to vary the oscillator frequency in proportion to the projected image.

Claims

1. In a phototypesetting machine having: a mechanism for holding a sheet of photographic paper in a plane and for advancing the paper along the plane; a disc having at least one ring of negative images of type characters and an identifying mark for each image of the ring, the disc being parallel to but spaced from the plane of the paper; a motor for rotating the disc; a strobe light on the opposite side of the disc from the paper; a lens between the paper and the disc and on the optical axis from the strobe light to the paper; a light source for illuminating the identifying marks of the disc in sequence as the disc is rotated; photoelectric sensing means for translating the illuminated identifying marks into electrical signals; means to select an individual character, the means producing an electrical signal identifying the selected character; a match detector for comparing the signal produced by the photoelectric sensing means and the signal from the selecting means to indicate when the selected character corresponds to the character on the disc detected by the sensing means; and a strobe firing circuit triggered by the match detector whereby the strobe light is fired to illuminate the selected character image of the disc and project the image through the lens to the paper, the improvement comprising: a character width indicating mark upon the disc for each character of the ring, an additional photoelectric sensing means being Provided to sense each width indicating mark and produce an electrical signal corresponding to the width of the associated character, and circuit means receiving the signal from the additional sensing means for controlling the mechanism for advancing the paper to advance the paper a distance proportional to the width of the projected character, said circuit means including an oscillator, an arithmetic updown register, a gate controlled by the additional photoelectric sensing means for supplying a pulse train proportional in length to the character width from the oscillator to the register to cause the register to count up, and a pulse generator responsive to movement of the paper to generate a pulse train proportional in length to the amount of paper advanced, the pulse train from the pulse generator causing the register to count down, wherein the paper advancing mechanism includes a second motor, a drive capstan driven by the motor and engaging the paper to advance the same and an electromagnetically operated brake operative to engage the paper and prevent its movement, the circuit means controlling the brake, the brake being controlled by the register whereby the brake is released while the register is counting down.