US2714352A

US2714352A - Apparatus for preparing make-ready mats for curved plates

Info

Publication number: US2714352A
Application number: US247076A
Authority: US
Inventors: Stanley M Rookyard
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-09-18
Filing date: 1951-09-18
Publication date: 1955-08-02
Anticipated expiration: 1972-08-02

Description

Aug. 2, 1955 s. M. ROOKYARD 2,714,352

APPARATUS FOR PREPARING MAKE-READY MATS FOR CURVED PLATES Filed Sept. 18, 1951 5 Sheets-Sheet 1 Aug. 2, 1955 s. M. ROOKYARD 2,714,352

APPARATUS FOR PREPARING MAKE-READY MATS FOR CURVED PLATES Filed Sept. 18, 1951 3 Sheets-Sheet 2 Z2 Z k.

IIIIIIHIIIIIIIIlllllllllllllllllll QQMM Aug. 2, 1955 s. M. ROOKYARD 2,714,352

APPARATUS FOR PREPARING MAKE-READY MATS FOR CURVED PLATES 3 Sheets-Sheet 3 Filed Sept. 18, 1951 United States Patent Thepresent invention relates to improvements in printing processes and more particularly to an improved method of processing curved plates used in cylindrical presses.

In printing on high speed rotary presses and particularly in mul ti-colour wet printing the electrotypes utilized heve to be processed for surface make-ready. Electrotypes so processed are known in the art as pre-makeready plates.

The pre-make-ready process in general consists of varying the height of the electrotype in proportion to its surface area, namely; 100% (solid) printing surface would require the maximum impression whereas an area of a dot value would require minimum impression.

For all practical purposes three different surface levels are all that is required, namely; highlight, middletone and shadow. (solid included). and middletone 4 0, 50, and and shadow 70, 80, and dot values (solid included).

This surface variation is brought about by first printing the original engraving or electrotype on a specially prepared. laminated paper, usually three laminations. The usual practice when large runs are to be made is to make amould from the original engraving and from the mould an electrotype is formed. Generally the electrotype so produced is backed up With metal to be several thou- Sandths of an inch thicker than the desired thickness of the finished plate. The laminated paper used is called mat paper and this is cut (with a knife or razor. blade) through. two laminations on all the shadow portions of the illustration. These portions are taken out of the mat. All middletone portions are cut through one lamination and are taken out of the mat. Highlight areas are left untouched.

The prepared mat paper is called a face mat and is placed in register on the face of the electrotype. A second mat isv prepared and cut just the opposite to the face that, namely; two laminations are cut out of the highlights, one out of the .middletones and the shadow is left untouched. This is called a back mat. and is placed in register on the back of the electrotype. The electrotype is then sand- I wiched between the face and back mats in perfect register and pressure is applied (hydraulic or mechanical) pushing the shadow portions up and the highlight portions down, leaving the middletone portions on an intermediate plane.

- The plate is then shaved on the back (with the face mat still on) to the required thickness. The electrotype is then curved for printing on high speed rotary presses. This is the usual practice and it has been found that the curving of these plates causes a stretch and a certain amount of distortion.

Attempts have been made to overcome this distortion by depositing the copper on to the mould in a curved position and backing up with base metal either in a curved casting box or a centrifugal casting machine. At the present time only a face mat has been used on these curved plates with the pressure being applied by means of a roller in a curved form or saddle. However, without the Highlight consists of 10, 20 l Patented Aug. 2, 1955 ICC use of a back mat, there is no recess for the highlight portions to sink into, which tends to squash the highlight dots thus impairing the highlight areas. i

The main reason why a back mat has not been generally employed is the problem of accurately preparing such a mat due to the difference in circumferences of the face and back of the curved plate plus the variance in platethickness. Due to this difference, the back mat must necessarily be shorter in order to register with the face mat in this curved position while the detail must be maintained proportionately. 4

The applicant recognizes this problem and aims to furnish a practical solution by providing: a method of preparing a back mat wherein the desired compensation or reduction in print length is taken care of in the printing of the laminated paper from the original engraving or electrotype. In accordance with the method of the invention a sheet of paper is fed into controlled impression contact with a printing plate having an impression area from which the mat is to be made, while the paper is positively restrained against the impression contact travel so as to be under constant longitudinal tension as it is being fed. The speed at which the paper is fed is; controlled so as to be reduced relative to the speed of the impression contact travel. The impression contact area between the paper and plate is maintained at a minimum during impression contact travel so as to retain the maximum amount of detail.

By this method a printed impression can be made on the paper from the plate that is shorter in length than the length of the plate impression area by a pre-determined amount. Briefly, in accordance with the present method, the paper is fed out of travel relative to the impression contact travel of the paper on to the plate and as it is positively restrained against the impression contact travel it is held back or in fact skids so as to reduce the length of the impression printed. on the paper relative to the plate impression area.

The applicant has found that an ideal condition is to maintain the width of the contact area of the paper at any one time during the impression contact with the plate at a minimum not exceeding the usual screen ruling of the engraving or the electrotype, i. e., approximately .010. In this way, each dot, or row of dots only is liable to distortion proportionately to the amount of which the paper is out of travel relative to the engraving, thus retaining the maximum amount of detail while reducing the length of the print.

With this concept in mind the applicant has devised a preferred apparatus by means of which the present method "may be carried out. This apparatus includes a main horizontal frame or bed oh which the engraving or electrotype is supported and retained. 'A'movable carriage is mounted on the frame so as to be capable of movement in either direction relative to the electrotype supported thereon. The carriage comprises essentially a pair of side plates or standards that are positioned at each side of the frame so as to extend above the bed. The lower portion of the side plates is provided with guiding rollers at each side which engage the lower edge of a rack extending along each side of the bed. A shaft extends between 'the side plates across the bed'of the apparatus and gears are mounted on each end of this shaft that are in meshed engagement with the teeth of the rack. A handle is connected to the shaft so that rotation of the handle causes the gears to move along the rack and "consequently moves the carriage along the bed relative to the electrotype bearing portion.

A first relatively large cylinder is mounted on a shaft extending between the upper portions of the side plates and a second relatively smaller cylinder is journalled between the side plates directly beneath and in alignment with the first cylinder.

The small cylinder is mounted on the side plates to extend across the frame adjacent the bed and a flexible paper supporting blanket is secured at one end to the large cylinder, extends around the lower cylinder and is again secured at the other end to the large cylinder, preferably by an adjustable bar to provide a means of tensioning. A gear train is provided between the frame and the large cylinder so that movement of the carriage along the bed also causes a corresponding rotation of the cylinder. Means are provided in the cylinder gear train whereby the cylinder can be rotated out of travel a controlled proportionate amount relative to the forward movement of the carriage. The blanket is made from a flexible but nonstretchable material and is provided with paper gripping means adapted to securely hold one end of a sheet of paper so that it is positively restrained against the impression travel of the carriage as the upper cylinder is rotated.

With this arrangement, when it is desired to make a print from an engraving or electrotype for the purpose of a back mat, the laminated paper is secured to the blanket and fed beneath the smaller cylinder. The rotation of the handle on the carriage moves the carriage and cylinders forward along the bed of the machine so that the paper comes into impression contact with the engraving or electrotype on the bed while it is restrained under tension against the impression contact travel. Adjustment of the gear train between the cylinder and frame is made to cause the paper held on the blanket to be fed out of travel relative to the forward travel of the carriage so that as it comes into contact with the plate it is held back, or in effect skids so as to reduce the length of the print.

In accordance with the present method and by means of the preferred apparatus described, a print can be made shorter than the original engraving or electrotype by a predetermined amount, making it suitable for a back mat as the difference in length compensates for the difference in circumference between the face and back of a curved printing plate.

Having thus generally described the nature of the invention particular reference will be made to the accompanying drawings illustrating a preferred embodiment thereof, and in which:

Figure 1 is a diagrammatic view in perspective elevation of a preferred apparatus by means of which the method of the invention may be carried out.

Figure 2 is a greatly enlarged view in plan of a portion of a proof made on an ordinary proof press showing a regularly spaced apart dot pattern as it would appear when made with the paper in exact travel with a cut or electrotype.

Figure 3 is a view corresponding to Figure 2 to show the same proof portion when made on the apparatus shown in Figure 1 to illustrate the regular shrinkage of pattern.

Figure 4 is an enlarged view of a portion of the supporting frame shown in Figure 1. to illustrate in more detail the cammiug arrangement of the rear guiding wheels.

Figure 5 is a reduced view in plan of the apparatus shown in Figure 1.

Figure 6 is an enlarged section of Figure 5 along the line 6-6 to illustrate the construction in more detail with the carriage and cylinders in the starting position.

Figure 7 is a view in end elevation of the apparatus shown in Figure 1 to illustrate the construction in more detail.

Figure 8 is a partial view in plan of the apparatus shown in Figure l to illustrate the cylinder speed varying arrangement in more detail.

Figure 9 is an enlarged detail view in section of a portion of the main cylinder as shown inFigure 7 along the line 99 to illustrate the paper gripper in more detail.

Figure 10 is an enlarged detail view in section of Figure 7 along the line 10-46 to illustrate the paper gripper in more detail.

Figure 11 is a sectional view corresponding to Figure 6 showing the carriage and cylinders at the end of the impression travel.

Figure 12 is a sectional view of Figure 5 along the line 12-12 to illustrate the construction of the carriage and cylinders in more detail.

Figure 13 is an exploded view of the top cylinder, blanket, paper grippers and the internal blanket backing plate to illustrate their construction and assembly in more detail.

With particular reference to Figures 1 and 2 of the drawings, a preferred construction of an apparatus which may be used to carry out the method of the invention is shown as being assembled on a frame 10 having a horizontal bed 11. Toothed racks 14 are mounted in corresponding register at each side of the frame 10 so as to extend outwardly therefrom along a major portion of the length of the frame.

A moveable carriage 12 is mounted on the frame 10 for controlled travel along the length of the racks 14. The carriage 12 is made up of a pair of standards or side plates 18 that are positioned at each side of the frame 11) so as to extend above the bed 11 exteriorly of the racks 14. The side plates 18 are guided and supported on the frame 10 by means of a first set of spaced apart gears 20 mounted on each end of a shaft 22 extending between the side plates 18 adjacent the rear edge, and a second set of spaced apart gears 24 mounted for free rotation on stub shafts 26 journalled in the side plates 18 at each side adjacent the leading edge. A handle 21 is secured to one end of the shaft 22 so that rotation of the handle 21 causes the gears 29 to move along the racks 14 and consequently moves the carriage 12 along the frame 10 relative to the bed 11 and the electrotypes A secured thereteo.

Guide rollers

30, 32 are mounted for rotation on stub shafts 34, mounted in the lower portion of the side plates 18 at each side, the rollers 30 being positioned adjacent the rear edge of the plates 18 andthe rollers 32 adjacent the leading edge.

Both sets of rollers 3t 32 are engaged with the lower surfaces of the racks 14 at each side of the frame 10 in substantial alignment with the

gears

20, 24 and the rear set of rollers 30 are adapted for cammed adjustment relative to the gears 20 so as to bring the carriage 12 into firm contact with the rack 14 (see Figure 4). The portion of each shaft 34 which acts as an axle for the rollers 30 is eccentric relative to the centre line of the shaft. An outstanding flange 46 intervenes the eccentric shaft portion and the remainder of the shaft that is mounted in and extends through the plate 18. The end of the shaft 34 protruding beyond the plate 18 is threaded and is engaged by a locking nut 38 so that tightening of the locking nut pulls the fiange 40 against the plate 18 and retains the eccentric shaft portion in the selected position. The end 41 of the shaft 34 protruding beyond the locking nut 38 is formed to accommodate a wrench or spanner so that the entire shaft can be rotated into cumming action as desired.

A first relatively large maincylinder is mounted on a shaft 52 that is journalled at each side between the upper portions of the side plates 18. A second relatively smaller impression backing cylinder 61) is also mounted between the side plates 18 beneath and in alignment with the cylinder 50. The ends of the cylinder are turned down and journalled in the side plates 18 in suitable bearings 61. The turned down ends of the cylinder 66 provide outstanding shoulders 62 which are adapted to bear against the inner surface of the rack 14 at each side so as to maintain the cylinder 60 in transverse alignment. The outer ends of the main body of the cylinder 60 bear directly on the bearer portions 64 of the frame 10 so that the cylinder 60 is positively main tained a fixed distance above the bed 11 of the frame 10.

lntorder to more positively retain the side plates- 18 in. vertical alignment and in correct spaced apart relationship, tie rods 66 are provided that extend across the frame between the side plates 18; The tie rods 66 are turned down at each end to provide an outstanding shoulder engaging the inner face of each plate 13 with the ends of the tie rods 66 protruding beyond the tie plate 18 threaded and engaged by suitable locking nuts 68. As the diameter of the cylinder 60 is relatively small, in the preferred construction approximately 1", and consequently liable to ,deflection, the tie rods 66 are disposed so as to serveas supporting. shafts for a pair of bearings or rollers 67 which are mounted over the rods 66 so as to be freely rotatable and to bear againstthe upper surface of, the cylinder 60 at two equidistant radial points.

A paper supporting blanket 70 is secured to the cylinder at one end and is mounted so as to extend downwardly therefromabout the cylinder and back upwardly to the cylinder 50 where the other end is adjustably secured to a tensioning bar 72. With particular reference to Figure 13, the blanketis made from a flexible but substantially non-stretchable material, and is secured to the cylinder 50 by a locking bar 74 which fits into a corresponding groove 76 provided in the outer periphery of the cylinder 50'. The firstend 71, of the blanket 70 is provided with a series of spaced apart openings 73 which register with corresponding openings 75, 77 provided in the bar 74 and cylinder groove 76 respectively and screws 81 are inserted through the bar 74, blanket 70; and engaged in thedrum 50 to securely anchor the blanket end 71.

The cylinder 50 is also provided with further radially spaced apart transverse grooves 80, 82 which are adapted to receive

outstanding bars

84, 36 secured to andprotruding from the rear face of a thin flexible metal sheet 88,. The groove is provided with a series of spaced apart tapped openings which register with correspondingopenings 92 provided in the plate 88 and bar 84. On assembly, the sheet 88 is secured to the cylinder 50 by suitable-screws passing through the openings 92 and r;

threadably engaging the openings 90 in the cylinder groove 80. The lower bar 36 on the sheet 88 is provided with tapped openings 94 and the blanket 70 includes a corresponding set of openings 96. The portion of the blanket 70containing the openings 96 is secured J to the flexible sheet 88 only by means of screws 98 which pass through the lower flange of a paper gripper 100', through'the blanket 70, and areengaged in the holes 94 so as to clamp the blanket between the paper gripper 100 and the flexible sheet 88.

The'paper gripper'100is a formed elongated strip of resilient sheet metal that is shaped so as to have upper 1'02 and lower 104 flanges connected by a-back flange 106. Thelower flange 104 of the gripper 100 includes spaced apart openings 108, 109 to accommodate the blanket retainingscrews 93 and a further set of clamping screws 110respectively. The upper flange 102 of the paper gripper includes spaced apart openings 112, 114to provide access to the screws 98 and to accommodate the clampiug screws 110 respectively. The clamping screws 110 are inserted through the openings 109, 114; Prior to the assembly of the blanket 70 to the plate 88'; the upper ends of the screws 110 being threadably engaged by adjusting nuts 116 so that tightening of the nuts 116 forces the upper 102 and lower flanges 1040f the paper'gripper100'together. The leadingedges of the

flanges

102, 104 are formed as indicated'at 120'to provide mating corrugations which are adapted to grip and positively retain the end of a sheet of paper B.

The rear edge of the blanket 70 is secured tov the cylinder 50 by means of the tensioning bar 72. The bar72 is of a square formation and is mounted between split standards 122 secured at each side of the cylinder 50. t The bar72 includes anelongated. slot 124 completely'therethrough and the outer ends of the bar are turned down so as to ,fit in, correspondingv openings aprovidedin thestandards122. Each of the, standards 122 is providedwith a ,set screw 128t-which passes, through one half of the standard andtis threadably engagedlinhthe opposite half 'so .that tightening, of the screw pulls. the two halves together to hold the bar 72 securely in the desired position. on assembly,,the blanket 70, after b'eingsecured at the end 71 to the cylinder 50and flexi: ble plate, 88, is fed downwards around the lower cylinder 60 and back upwards to the bar 72. The rear-edge of the blanket 70 is fed through theslot 1241 and.the bar 72rotated totight en the blanket. The.standards-,122 are then tightened to hold the bar 72 in the desired position. Preferably, the outer ends of the bar 72 are provided with a plurality of radially spaced apart openings 130 which are adapted to accommodatea pin or key, so that the bar 72 can be easily rotatedin. the manner of a capstan to provide the desired tension on the blanket 70.

The main purpose in providing the flexible plate 88 between the blanket 70 and the cylinder 50 and attaching the paper gripper 100 to the flexible plate 83 instead of directly to the cylinder 50 is to allow the mat paper to be fed as close as possible to the impression cylinder 60 while maintaining the paperunder positive restraint. If the paper gripper 100 were fastened directly to the cylinder 50 the cylinder could only be rotated till the gripper arrived at the tangent point between the cylinder and the blanket 70. This would mean that the portion of the paper between the impression cylinder 60 and the gripper 100 would be wasted. While it is contemplated that the paper gripper 100 could 'be fastened directly tothe blanket 7 0 the provision of the positively located and more durable flexible plate 88 ensures that the paper is. retained and restrained positively while it is-fed almost to the.nip bee tween the impression cylinder 60 and the engraving.

In order toobtain the desired drive to the cylinder 50 one end of the shaft 52 on which the cylinder 50 is mounted extends-beyond the side plate 18a and a large helical gear 200 is adjustably secured to the shaft end. A gear train comprising an idler helical gear 202, a sliding helical gear 204, and a helical gear 206 mounted in a common shaft with a spur gear208 is mountedtfor free rotation on the side plate 18a. The top helicaltgear 202is in meshed engagement With the helical gear 200 and theb'ottom spur gear 208 is in mesh. with the idler gear 24 which in turn is in engagement Withthe rack 14 so that movement of the carriage 12 through the rotation of the driving gears 20 also causes a corresponding rotation of the cylinder 50. This gearing arrangement is such that the peripheral speed of the cylinder 50 and consequently the blanket 70 isnormally equal to the impression contact travel of the carriage 12 along the racks 14.

However, in accordance with the method of thepresent invention it is necessary that the peripheral speed of the blanket 70 or feeding speed of the paper as held by the paper gripper 100 be less than the impression contact travel of the carriage 12. This is accomplished'by-the moving outwards of the sliding helical gear 204during the forward travel of the carriage 12.

With. particular reference to Figures 7 and 8 of the drawings, the

gears

202, 204, 206 and 208 are mounted on stub shafts journalled in bearing blocks extending from the supporting exterior face of the side plate 18a. Thestub shaft 210 supporting the, slidinghelical gear 204 is slidably mounted within the bearing block 220 and is of suflicient length to extend considerably beyond the gear 204 to a sliding connection with a cam bar 222. The cam bar 222 is slotted as indicated at .224 along a major portion of its length and the end of the shaft210 fits within this slot whereit is retained for slidingmovement by outstanding collars 226. One end of the cam bar. 222a is pivotally sescured as indicated at 229 to a standard 230 projecting from the .side of the frame 10 while the opposite downwardly extending end 222b is provided with a pair of internally threaded bosses 232 which are engaged by a threaded adjusting screw 234. The adjusting screw 234 is journalled in the frame so as to extend from one side to the other and the end of the screw 234 remote from the bar 222 protrudes beyond the side of the frame 10 and is provided with an indicator knob 240 having an indicator pointer 242. A radially ruled indicator plate 244 is provided on the side of the frame 10 from which the knob 240 protrudes so that the relative position of the indicator pointer 242 and consequently the degree of rotation of the adjusting screw 234 is clearly shown.

The amount or degree of rotation of the adjusting screw 234, through the connection with the threaded bosses 232, also causes a corresponding angular movement of the cam bar 222 from a parallel alignment with the side of the frame 10 so that the shaft 210 is urged outwardly a predetermined distance as it travels along the slot of the cam bar 222. This movement of the shaft 210 causes a corresponding outward movement of the helical gear 204 relative to the

gears

202, 208 and due to the helical formation of the gears a proportionate amount of the forward travel of the gears is transmitted or lost by the rotating sideways motion of the helical gear 204. This in turn causes the gear 202 to be rotated at a slightly slower speed than the gear 208 which being on a common shaft with the gear 206 is rotated at the same speed as the gear 24 through engagement with the rack 14. The gear 202 being in meshed contact with the large helical gear 200, the cylinder 50 is rotated at a proportionately slower speed than the speed of forward travel of the carriage 12.

It will be understood that the actual variance in speed is minute in that the cylinder 50 does not travel more than approximately /2 of a complete revolution at any time and the amount of variance is spread out through the length of the cam bar 222 during the whole forward stroke. For example, the maximum shrinkage required over a maximum print length is about A on a 9" print or about "i /2%.

The method of the invention is carried out by means of this apparatus by first placing the engraving or electrotype, from which the back mat is to be made, on the bed 11 of the apparatus. In the present drawings there are two such plates shown and indicated as A. These plates A are secured and aligned in the usual manner and shimmed to provide the correct impression contact with the paper. The conventional type of ink distribution and impression trip may be employed but is not necessary since the plates can be inked on a conventional proof press. The laminated paper B is then secured to the paper gripper 100 with the carriage 12 in the starting position shown in Figure 6.

The indicator knob 240 is then set relative to the indicator plate 244 so as toproduce the desired reduction in print length relative to the amount of curvature and plate thickness of the plate for which the back mat is to be made. The handle 21 is then rotated and the leading edge of the paper fed beneath the blanket 70 under the impression cylinder 60, care being taken to pull the paper evenly against the blanket 70 prior to the impression contact between the paper B and the plates A. The continued rotation of the handle 21 moves the carriage 12 along the racks 14 so that the paper is fed by the blanket 70 between the impression cylinder 60 and the plates A.

'As the paper is fed between the impression cylinder 60 and the plates the leading edge is pulled manually upwardly and away from the impression cylinder 60 so as to clear the driving shaft 22 and maintain the printed paper at an even tension as it leaves the impression contact area. In this respect, it is contemplated that suitable mechanical means might be utilized for this tensioning but on experiment it has been found that for all practical purposes slight manual tension is sufiicient.

The trailing edge of the paper B is positively held in the paper gripper 100 so that the speed of feed of the paper is controlled by the speed of travel of the blanket '70 and as the speed of travel of the blanket 70 is controlled by the gearing arrangement driving the cylinder 50 so as to be proportionately less than the forward impression contact travel of the carriage 12 the portion of the paper B in impression contact at any one time with the plates A is held back so that it skids so as to reduce the length of the impression printed on the paper 8 relative to the impression area of the plates A.

Due to the relatively small diameter of the impression cylinder 60, the width of the impression contact area during the skidding is maintained at a minimum relative to the usual screen ruling of the plate, for example,

in the preferred construction illustrated, the impression cylinder is approximately 1 in diameter giving an impression area of approximately .010 in width. In this way each dot or row of dots making up the impression area of the plates A only is liable to distortion proportionately to the amount at which the paper B is fed out or" travel relative to the engraving while reducing the length of the print impression from the impression area of the plate. As an example, this is shown diagrammatically in Figures 2 and 3 wherein Figure 2 represents a greatly enlarged portion of the plate impression as it would appear when printed normally with the paper feed and impression contact travel in register while Figure 3 shows the same plate impression portion as it app'ears when printed in a reduced length in accordance with the method of the invention.

As will be understood by reference to the preceding description and accompanying drawings, the preferred apparatus shown can be used for printing the face mats for a plate and then by adjustment of the indicator knob 240 can be used to print the shorter back mats for the plate. The required difference in any print length as required by the variation in plate curvature and thickness can be easily predetermined by reference to the indicator plate 244 and the apparatus set to compensate for the desired print length.

I claim:

1. An apparatus for printing pre-make-ready back mats for curved plates adapted for use on cylindrical presses, said apparatus comprising, a frame including a horizontal bed adapted to support a printing plate, a carriage mounted on said frame for controlled impression contact travel relative to said bed, co-operating gear means on said carriage and rack means on said frame adapted to guide said carriage during said impression contact travel, means to actuate said carriage gear means, paper supporting means mounted on said carriage, paper retaining means mounted on said paper supporting means, said paper supporting means being adapted to support a I sheet of paper positively retained by said paper retaining means so as to bring said paper into impression contact with a plate bearing a screen ruled impression area and supported on said bed, an impression cylinder mounted for rotation on said carriage co-operating with said paper supporting means adapted to maintain the width of said impression contact area between said paper and said plate substantially equal to the width between the screen ruling of the impression plate, variable drive means between said frame and said paper supporting means and adjustable control means adapted to act on said variable drive means whereby the speed of said paper feeding means may be varied relative to the speed of travel of said carriage impression contact travel so that a print on said paper from said plate may be reduced in length relative to the impression area of said plate proportionately to the difference in speed ratio of said paper feed means and carriage impression travel while retaining maximum detail.

2. An apparatus for printing pre-make-ready back mats for curved plates adapted for use on cylindrical 9 presses comprising, a frame including a horizontal bed adapted to support a printing plate, a carriage mounted on said frame for controlled impression contact travel along said frame relative to said bed, racks on said frame and registering gears on said carriage adapted to guide and urge said carriage along said frame, means to actuate said gears, a first upper cylinder and a second lower cylinder mounted in axial alignment on said carriage so as to extend across said bed, a flexible paper supporting member mounted on said first cylinder and extending about said second cylinder to constitute a drive connection therebetween, paper retaining means mounted on said paper supporting member adapted to positively retain a sheet of paper fed in impression contact between said paper supporting member and a screen ruled impression plate supported on said bed, said second lower cylinder being of a diameter adapted to maintain the width of the impression contact area between said paper and plate substantially equal to the width between the screen ruling of the impression plate, variable drive means between said first cylinder and said carriage gears adapted to rotate said cylinder during the impression contact travel of said carriage, and adjustable control means operatively connected with said variable drive means whereby the speed of feeding travel of said paper retaining and feeding means may be reduced relative to the speed of impression contact travel of said carriage.

3. An apparatus as claimed in claim 2, wherein said first upper cylinder is of considerably greater diameter than said second lower cylinder.

4. An apparatus as claimed in claim 3, wherein the diameter of said second lower cylinder is about 1".

5. An apparatus for pre-make-ready back mats for curved plates adapted for use on cylindrical presses comprising, a frame including a horizontal bed adapted to support a printing plate, a carriage mounted on said frame for controlled impression contact travel along said frame relative to said bed, racks on said frame and registering gears on said carriage adapted to guide and urge said carriage along said frame, means to actuate said gears, a first upper cylinder and a second lower cylinder mounted in axial alignment on said carriage so as to extend across said bed, a flexible paper supporting member mounted on said first cylinder and extending about said second cylinder to constitute a drive connection therebetween, paper retaining means mounted on said paper supporting member adapted to positively retain a sheet of paper fed in impression contact between said paper supporting means and a screen ruled impression plate supported on said bed, said second lower cylinder being of a diameter to maintain the width of the impression contact area between said paper and plate substantially equal to the Width between the screen ruling of the impression plate, variable drive means between said first cylinder and said carriage gears including a first helical gear connected to said first cylinder, at second helical gear mounted on said carriage, a third helical gear mounted on said carriage for sliding axial movement relative thereto, a fourth helical gear on a common shaft with a spur gear mounted on said carriage, said first, second, third, and fourth helical gears being intermeshed with said spur gear in meshed engagement with one of said carriage gears, an adjustable control means operatively connected to said slidably mounted third helical gear and adapted to move said gear towards and away from said carriage, whereby the speed of feeding travel of said paper retaining and feeding means may be varied relative to the speed of impression contact travel of said carriage.

6. An apparatus as claimed in claim 5, wherein said first upper cylinder is of considerably greater diameter than said second lower cylinder.

7. An apparatus as claimed in claim 6, wherein the diameter of said second cylinder is about 1".

8. An apparatus as claimed in claim 5, wherein said adjustable control means comprising an elongated cam bar having an internal elongated slot is pivotally connected at one end to said frame so as to extend parallel therewith, the other end of said cam bar being provided with an internally threaded bushing, said third helical gear is secured to a stub shaft having one end slidably journalled in said cariage with the other end extending beyond said gear and slidably engaging said cam bar slot, and an elongated rod having a threaded end portion is journalled in said frame with said threaded end engaged in said cam bar threaded bushing, whereby rotation of said rod is adapted to move said cam bar out of parallel alignment with said frame and said cam bar is adapted to act on said shaft end to urge said helical gear towards and away from said carriage.

References Cited in the file of this patent UNITED STATES PATENTS 744,371 Logue Nov. 17, 1903 808,455 King Dec. 26, 1905 908,267 Jacobson Dec. 29, 1908 1,128,351 Motley Feb. 16, 1915 1,929,068 Isbell Oct. 3, 1933 2,031,222 Mazzocco Feb. 18, 1936 2,256,921 Bishop Sept. 23, 1941 2,587,439 Bungay Feb. 26, 1952 2,619,901 Harrold Dec. 2, 1952 2,623,458 Peal et al Dec. 30, 1952