US3550283A - Method and apparatus for applying a printing plate to a support saddle - Google Patents

Description

E. BERNARD! ETAI- METHOD AND APPARATUS FOR APPLYING A PRINTING Dec. 29, 1970 PLATE TO A SUPPORT SADDLE Filed April 2, 1968 4 Sheets-Sheet 1 w m 8WD 8 RAZ Y ON a TR NE R W i 0 N n EL 3% 5w 1 Dec. 29, 1970 BERNARDl ET AL 3,550,283

METHOD AND APPARATUS FOR APPLYING A PRINTING PLATE TO A SUPPORT SADDLE Filed April 2, 1968 4 Sheets-Sheet 2 FIG. 2

////////////7777 ////////////LZZ\\\ INVENTOR EUGENE L.BERN RDI RgDOLPH T. BRAZDOVIC I I, f h ATToRr z g Dec. 29, 1970 EL. BERNARDI ETAL 3,550,283 METHOD AND APPARATUS FOR APPLYING A PRINTING PLATE TO A SUPPORT SADDLE Filed April 2, 1968 Sheets-$hect 8 INVENTORS EUGENE L. BERNARDI RUDOLPH T. BRAZDOVI i E I 6, ATTORNEY Dec. 29, 1970 BERNARD| ET AL 3,550,283

METHOD AND APPARATUS FOR APPLYING A PRINTING PLATE TO A SUPPORT SADDLE 54 FIG. 7 53 v 52 m, L 10mm] I 53mm a r 33 3 so ll! 34 H1 46 :3 W i 46 36 h IUINUUINN WNW! {ML-:3 1 :HWL-LZ:11111-513 INVENTORS 37 EUGENE L. BERNARDI RUDOLPH T. BRAZDOVlC RNEYS United States Patent Olhce 3,550,283 Patented Dec. 29, 1970 3,550,283 METHOD AND APPARATUS FOR APPLYING A PRINTING PLATE TO A SUPPORT SADDLE Eugene L. Bernardi, Oakland, Calif., and Rudolph T. Brazdovic, Pittstown, N.J., assignors of one-half to Wood Industries, Inc., Plainfield, N.J., a corporation of Virginia, and one-half to Reichhold Chemicals, Inc., White Plains, N.Y., a corporation of Delaware Filed Apr. 2, 1%8, Ser. No. 718,656 Int. Cl. B41b 1/00 US. Cl. 33184.5 5 Claims ABSTRACT OF THE DISCLOSURE Apparatus for accurately positioning the printing portion of a flexible flat printing plate onto a curved support saddle which apparatus includes a movable layout table having thereon a movable rear register stop adapted to engage with a raised reference or printing portion cast on a printing plate to preposition the printing portion of the plate relative to the page to be printed. Means are provided for rotating the saddle to a preselected position such that when the table and plate thereon are moved towards the saddle, the underside of the head of the plate will engage the curved surface of the saddle along a tagent thereto at a desired point between the head and foot of the saddle equal to the position down from the top of the page that the top of the printed portion is to appear. Pressure means are provided for imparting a radial pressure to the plate and saddle and rotation means are provided to rotate the saddle and pull the plate from the layout table.

Method for positioning the printing portion of a flexible flat printing plate onto a curved support saddle including the steps of positioning a rear register stop on a layout table depicting the page to be printed at a point equivalent to the position that a raised reference point or preselected printed matter is to be positioned on the page, bringing a printing plate having a raised reference portion or preselected printing portion into contact with the stop, circumferentially positioning a curved support saddle at a point where the bottom surface of the head end of the plate may engage the saddle along a tangent thereto at a point which is a predetermined distance from the head of the saddle, moving the table and plate towards the saddle such that the plate engages the saddle along a tangent thereto, and applying a radial force to the saddle plate at the point of tangency while rotating the saddle to withdraw the plate from the table.

BACKGROUND OF THE INVENTION This invention relates to a printing plate applicator and more particularly to apparatus and method by which a thin printing plate may be accurately affixed to a curved support saddle.

It is necessary in multi-color printing that a separate printing plate be provided for each color printed which in turn requires that each of the several plates be accurately positioned on the printing cylinders of a press if the colors when printed are to accurately register without undesirable overlap.

Heretofore, the production of color printing plates and the positioning of the plate in printing press equipment has involved complex and time-consuming operations to assure accurate registry. The time required to prepare and position the plates is of major importance when rotary cylinder type press equipment is used such as in the printing of newspapers where minimum setup time is of extreme importance.

It has been the usual practice when preparing plates for color printing to photograph the original copy utilizing suitable filters in order that separate photographic prints may be made of the copy in each of the basic colors to be printed. Register marks in the form of cross hairs or bulls-eye markings are applied to the margin of the original copy utilizing register bars and these marks in turn are transferred to each of the photographic prints. The prints are then reduced to metal or plastic plates by conventional photo-chemical or mechanical means with the register markings on the prints being transferred at the same time. The engraver then utilizes the register marks on the plates to cut and trim the four sides of the plates to assure that all of the plates will register accurately with one another.

These etched or engraved plates are then placed in a printing form or chase utilizing the register bars to assure accurate positioning in the form. This is usually accomplished by having four holes drilled in the register bars. These holes are then transferred to a block or base which is 'fitted in the form and pins then are inserted into the holes in order that each of the engraved plates may be successively positioned in the form. A matrix is molded from each plate while in the form after which it is removed and carefully trimmed. Each matrix is then carefully positioned in a stereotype plate casting machine from which a heavy metal plate is cast. This metal plate is then accurately machined to size and any dead or unwanted portions of the plate are routed out.

This manner of producing the individual metal printing plates necessary to produce a single color print is timeconsuming, expensive and subject to errors. For example, the pins positioning the engraved plates in the printing form may become bent such that the plates will become misaligned in the form. The matrices must be carefully dried in order to control shrinking and must be carefully trimmed to size, itself a diflicult procedure. Further the matrices must be carefully positioned in the casting box. Any error in any of the above steps can result in faulty printing.

We propose to overcome many of the difii'culties inherent in the conventional casting of stereotype metal printing plates by utilizing a thin flexible plastic printing plate which may be cast in a fiat position in a casting machine having therein a matrix for each color plate made from the original copy and on which a reference mark, for example a margin line, has been noted. The plastic plate cast from the machine is then accurately positioned onto a layout table by utilizing a raised reference or printing portion cast onto the plate and which corresponds to the reference mark on the original copy and the plate is then transferred to a support saddle which is applied directly to the printing cylinder of a printing press. This use of a raised reference or printing portion of all the plates of a multi-color print as a base point from which to position the plates eliminates the need for incorporating any holes in the base of a printing form and the attendant use of setting pins, any precise trimming of mats, any critical placement of mats in a stereotype plate casting machine or of trimming the sides of the cast printing plate. Further, if more than one printing plate is to be cast, it merely involves using the same casting machine with the same matrices so that the plates cast from a single matrix are uniform.

Broadly our invention is directed to an apparatus and method by which a thin printing plate is applied to a curved support saddle so as to assure accurate positioning of the plate on the saddle both in circumferential and axial directions. The apparatus includes a rotatable cylinder which is identical in diameter to the printing cylinder of a press and to which a curved support saddle is held by holding means similar to the holding means by which the saddle is to be locked to the printing cylinder. The outer curved surface of the saddle has an adhesive thereon and means in the form of a pressure roll are provided such that when one end of a printing plate is brought into contact with the saddle, the printing plate may be rolled onto the saddle when the saddle cylinder is rotated relative to the pressure roll. Adjustable stop and index means are associated with the saddle cylinder so that the circumferential point of initial contact of the top end of the printing plate will be circumferentially positioned on the saddle and will correspond to a pre-set distance from the top of a printed page. A moveable flat layout table is provided such that the printing portion of a flat printing plate may be accurately positioned laterally with respect to the saddle to provide column register and also such that the printing portions adjacent the tail end of the plate may be pre-positioned with respect to a base line which in turn turn is positioned relative to the distance from the top of the printed page to be printed. The table is moveable with respect to the saddle cylinder such that the top edge of the printing plate carried by the table may be brought into engagement with the outer adhesive surface of the saddle along a tangent thereto and at a point where the pressure rolls forms a nip with the saddle. Means are provided for rotating the cylinder such that the plate may be pulled from the layout table and rolled onto the saddle by the application of a radial force of the pressure roll.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken side view of a plate applicator constructed according to the invention;

FIG. 2 is a perspective view illustrating a saddle to which a printing plate is to be affixed;

FIG. 3 is a perspective view illustrating means for locking the saddle of FIG. 2 onto a saddle cylinder of the plate applicator;

FIG. 4 is an end view of the saddle cylinder of FIG. 3 and a portion of the applicator illustrating an adjustable stop means for circumferentially positioning the cylinder of FIG. 3;

FIG. 5 is a plan view of the stop means of FIG. 4 shown associated with an index means carried on the cylinder;

FIG. 6 is a sectional view of FIG. 5 taken along lines VIVI;

FIG. 7 is a plan view of a portion of the applicator shown in FIG. 1 and more particularly a layout table; and

FIG. 8 is an enlarged sectional view taken along lines VIII-VIII of FIG. 7 illustrating a register means for positioning a printing plate on the layout table.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there is illustrated a plate applicator 1 having a plate applicator portion 2 and a layout table portion 3 on which a thin flexible plastic printing plate P having a head or top end and a tail or bottom end may be accurately positioned. The applicator portion 2 comprises a rotatable saddle cylinder 4 of the same diameter as the printing cylinder of a printing press to which the saddle is to be affixed. The cylinder 4 is rotated about its shaft 5 by a drive means 6 which connects with the shaft by a drive chain 7.

As shown in FIGS. 2 and 3, the saddle S to which the thin printing plate P is to be attached comprises a semicircular member which is attached to the cylinder 4 by means of a fixed clamp 8 and movable clamps 9 which are slidable in tracks 10 contained on the surface of the saddle cylinder and which extend parallel to the cylinder axis. The saddle also has head and tail ends corresponding in direction to the head and tail ends of the plate P. Clamps 9 are moved in their tracks 10 by threaded screws 11 which are turned by knobs 12 to force an end of the plate into contact with the fixed clamp 8 and thus lock the saddle to the cylinder. Additional clamping pressure is obtained by lock-up rods 12' acting on cam discs 13 and 14. These clamps are identical with clamps on the printing cylinder of the printing press which are utilized to secure the saddle to the printing cylinder.

The cylinder 4 is further provided with a locating bar 15 adapted to engage one circumferential end of a saddle such that the saddle will be circumferenially positioned with respect to the cylinder prior to the application of the holding clamps.

While we have illustrated in FIGS. 2 and 3 a saddle which is adapted to be held to a printing cylinder by end clamps, it is obvious that the saddle could be afiixed to the cylinder by other lock-up devices which are similar to the lock-up devices for securing the saddle to the printing cylinder of a press. For example, conventional underside tension lock-uphooks may be used which would engage recesses or pockets cut into the under surface of the saddle. The cylinder 4 would then have similar underside tension lock-up hooks on its surface positioned in the same manner as tension lock-up hooks in the printing cylinder to which the saddle is eventually to be applied. In such an arrangement, it would not be necessary to include the locating bar 15 on the saddle cylinder as the register hooks would serve to circumferentially acurately position the saddle onto the cylinder 4. The advantage of using the same type lock-up devices on the cylinder of the applicator as on the cylinder of the press is that the chance of plate misalignment when the saddle is applied to the press is reduced.

The applicator portion further comprises a pressure roll 16 which is rotatably carried on an arm 17 which in turn is pivotable about a shaft 18. Arm 17 is connected by crank 19 to a piston rod 20 of a fluid motor 21 such that when the piston rod 20 moves in an upward direction as shown in FIG. 1, the roll 16 will be moved in a counterclockwise direction to exert a radial force on the printing plate P to force it into intimate contact with the surface of the saddle S to which an adhesive, preferably a double-faced adhesive sheet, has been previously applied.

The plate P is preferably of a thin, light flexible plastic material which can be rolled around the surface of the saddle without cracking when the cylinder 4 is rotated in a clockwise direction by the drive means 6.

It is necessary that the plate P be accurately positioned on the surface of the saddle to assure that when the saddle is applied to a printing cylinder of a pressure, the plate will be in accurate registry with other color plates applied to other cylinders. This requires that the plate be accurately positioned both longitudinally and circumferentially with respect to the saddle.

Circumferential positioning of the printing plate on the saddle is accomplished by pre-setting the rotational position of the saddle cylinder such that the top or head end of the printing portion of the printing plate when brought into position to contact the adhesive surface of the sad dle as shown in FIG. 1 will be at a pre-set distance from the top of the page on which the plate will eventually print. This is achieved by rotating the cylinder 4 in a clockwise direction as shown in FIG. 1 until a retractable plunger 22 shown in FIGS. 4, 5 and 6, engages a stop surface 23 on adjustable bracket 24. The bracket 24 has a curved slot 25 therein through which screws 26 extend for adjustably securing the bracket to the saddle cylinder. It is seen by reference to FIG. 4, that as the bracket 24 is moved counterclockwise with respect to the cylinder, that the point of engagement of the stopping surface 23 with the plunger 22 will be moved toward the left end fo the saddle which is adjacent the top of the page to be printed. Conversely, if the bracket 24 is moved clockwise with respect to the cylinder 4, the point of engagement will be moved closer toward the right end of the saddle adjacent the bottom of the page to be printed.

Precise positioning of the saddle cvlinder is accomplished by utilizing a scale 27 contained on the end of the cylinder which is calibrated to indicate the distance of the bottom edge of a raised reference or printing portion of the plate from the top of the page to be printed. The scale is conveniently marked in inches taking into ac- :ount any change of dimension that may exist between the page as printed and the actual dimensions of the plastic plate.

Plunger 22 is connected to a piston inside an air cylinder 28 such that the plunger may be fully retracted in the event it is desired to rotate the cylinder past the adjustable stop means when removing or applying a saddle.

Referring to FIGS. 7 and 8, there is illustrated a moveable layout table 3 on which the flat printing plate is initially layed out and positioned relative to the page which is to be printed. The table 3 has a table surface 30 which is large enough to accommodate a single plate of full page size. Surface 30 has thereon two longitudinally extending slots 31 which serve as guides for a movable rear register bar 32 and a lateral slot 33 in which side register units 34 may slide to engage the raised printing portion of a printing plate.

Scales 35 are provided on both sides of the table from which the stop bar may be positioned. The scales are preferably calibrated in inches to measure the effective length of the fiat printing plate. Thus if a plate having an effective length 12 inches long is to be applied to a saddle, the rear register bar is set at the 12 inches on the scales. This assures that the head or top edge of the plate will overhang the end of the table a predetermined amount, as shown in FIG. 1, and will engage the saddle along a predetermined line when the cylinder is set at a predetermined position and when the table is moved toward the cylinder. In this manner, the top of the printing portion of the printing plate will be positioned a predetermined distance from the top of the page to be printed.

The rear register bar has thereon screws 36 which are threade into blocks 37 which in turn slide on the slots 31. In this manner, the rear register bar may be locked into position by turning screws 36.

The rear register bar 32 comprises in part a stop 38 adapted to engage an edge 39 of the printing plate which forms the bottom end of the printing portion of the plate. This edge is cast with the printing portion of the plate and provides an accurate base line from which to measure the length of the printing portion, i.e., effective length of the printing plate. The stop overhangs a bottom slide portion 40 of the bar 32 and also a dead portion 41 of the plate which usually comprises excess flashing resulting from the casting operation and which comprises a nonprinting portion of the plate. This mode of engagement of the plate with the rear register bar eliminates any need of the edges of the plate being accurately trimmed after it is cast since the point from which the measurement of the plate is made used in positioning the plate on the saddle is cast along with the printing portion.

A plurality of undercut clamps 45 are slidably positioned along the bar 32 to hold the plate in position once the stop engages the edge 39. The clamps are provided with screws 46 in order that they may be locked in place. A spring biased ball 47 is contained in a threaded stud 48 carried by the clamp in order to hold the plate firmly down on the surface 30 of the table. In addition, the top of the two outer clamps have reference lines (not shown) on the top thereof which are even with the end of the margin bar whereby the position of the end of the margin bar may be read on the scales 35.

The layout table is also provided with column lines 49 similar to the column lines on the page to be printed. By utilizing these column lines, the plate may be positioned laterally with respect to the table by the use of side units 50. Side units 50 are generally similar to units 45 and include the margin stop arrangement for engaging a side of the printed portion similar to edge 39. Side units 34 also have a margin stop arrangement for accurately positioning the top portion of the printing plate.

The table 3 is mounted on slides 52 carried by the frame of the applicator such that it may be manually moved towards and away from the saddle cylinder. When the table is moved to the position where shoulder 53 on the frame contacts shoulder 54- of the table, the top end of the plate will be in line contact with the saddle.

The procedure for setting a plate on a saddle is as follows. The operator first positions the fiat plate on the layout table relative to the page which is to be printed. For example, if the plate is for a color print three columns wide between columns 2 and 6 of the page and the print is twelve inches long with the top of the print to be two inches down from the top of the page, the rear register bar '32 is set at 12 inches on scale 35 with the margin stop 38 of the bar 32 engaging the edge of the printing portion. The side register units 34 and 45 are then moved into position such that their stops coincide with column lines 2 and 6. The screws of all clamps are then tightened. In the event that the matter to be printed does not have a printed portion at the bottom such that the printing plate would not normally have a corresponding printing portion which would be engaged with a stop 38, such a portion could nevertheless be cast with the plate from a reference mark made on the original copy such that it would appear on all plates of the same color scene and subsequently be routed out after the plate has been applied to a saddle.

The adjustable stop on the cylinder is then set to fourteen inches on scale 27 (12 inches length of plate plus two inches from top of plate to top of page) and the cylinder rotated until plunger 22 engages against stop surface 23 which circumferentially locates the circumferential portion of the saddle at which the top end of a plate will engage the saddle. The saddle is then clamped onto the saddle cylinder and adhesive applied to the outer surface thereof. The layout table 3 is then moved towards the saddle cylinder until the shoulders 53 and 54 engage at which position the top inner edge of the plate will contact the outer surface of the saddle. Fluid motor 21 is then actuated bringing pressure roll 16 down onto the plate to force the plate into intimate contact with the adhesive surface on the saddle. Drive means 6 is then actuated which rotates cylinder 4 pulling the plate P from table 3 between the roll 16 and saddle whereby the plate is rolled smoothly and evenly onto the saddle. Subsequent plates for the remainder of the colors of the print may be applied to saddles without change of the settings of the adjustable stops and rear register bar which further assures that all plates will engage their saddles in the same positions thus promoting accurate registry of the several colors when printed.

While we have described a preferred embodiment of our invention, it is obvious that minor changes could be made and still come Within the scope of the invention. For example, the layout table instead of being movable along a straight line towards the saddle cylinder, could move towards the cylinder by a pivotable action whereby the end of the plate would be pivoted into the position shown in a dotted line in FIG. 1. Further, the layout table and adjustable stop means could be mounted on a press whereby the plate would be aflixed to a saddle mounted on a printing plate cylinder.

Also instead of using the specific undercut clamps 45 as illustrated in the drawings, other clamps could be used which could have a stop similar to 38 thereon for engaging and positioning a plate. For example, a stop similar to 38 could be mounted directly to an adjustable clamp which could be adjustably positioned with respect to the plate.

We claim:

1. A printing plate applicator for applying a thin flexible printing plate having a tail end, a head end and an under surface to a curced support saddle where the printing plate has a raised reference portion thereon adjacent the tail end of the plate, raised printing portions thereon and non-printing portions thereon, said applicator comprising a rotatable cylinder adapted to mount a saddle, rotation means for rotating said cylinder, locating and locking means on said cylinder for circumferentially positioning and locking a saddle thereon, adjustable stop means for limiting rotational movement of said cylinder, a movable layout table having a top end adapted to support said printing plate, rear register means on said table for accurately positioning said printing plate thereon to provide a predetermined overhang of the head end of a plate over the top end of the layout table including a rear register stop spaced vertically above said table a distance greater than the thickness of the non-printing portions of the plate and less than the raised reference portion on the plate whereby said stop may overlie a nonprinting portion of said plate to engage a side of the raised reference portion, means mounting said table for movement towards said cylinder whereby the under surface of the head end of a plate may engage a curved saddle along a tangent thereto, and pressure means spaced from and extending parallel to said cylinder for exerting a radial pressure on a printing plate at the point of tangential engagement of the plate and saddle to urge the plate into firm engagement with the saddle whereby rotation of the saddle will draw the plate from the layout tab-1e.

2. A printing plate applicator according to claim 1 having in addition a first index scale on said cylinder calibrated in units of distance from the top of the page to be printed to the top of the printed matter to be included on the page by which said adjustable stop means is positioned circumferentially with respect to said cylinder whereby the initial point of tangential engagement on a saddle by a plate may be predetermined when said table and a plate thereon are moved towards a saddle.

3. A printing plate applicator according to claim 2 wherein said layout table includes a second index scale and a marker associated with the rear register means with said scale calibrated to measure units of length of plate from an edge of a raised printed portion adjacent the head end of the plate to a raised reference portion and wherein the distance from the rear register means to the top end of the table at any setting of the marker on the second index scale is less than the reading on the second scale by an amount equal to the predetermined overhang of the head portion of a plate when the rear register stop engages the raised reference portion on the plate.

4. A method of accurately positioning and affixing a series of thin printing plates making up a single multicolor scene to be printed onto a plurality of curved support saddles wherein each plate has a tail end, a head end,

a raised printing portion and an under surface and each said saddle has a head end comprising the steps of casting a raised reference portion onto each printing plate near the tail end thereof wherein each reference portion in the series is in the same position with respect to the printing portion of each of the plates, positioning a raised rear register stop on a page layout table having a top end where the distance between the stop and the top end of the table is equal to the distance between the raised reference portion and the edge of the printing portion adjacent the head end of each plate less a predetermined distance equal to a predetermined overhang of the head end of a plate over the top end of the layout table when the rear register stop engages the raised reference portion of a plate, successively for each plate circumferentially positioning a saddle such that the under surface of a head end of a plate will engage the outer surface of the saddle along a tangent thereto at a point which is at a predetermined distance from the head end of the saddle which distance is equal to the distance from the top of the page to be printed to the printed matter to be printed by the plate, positioning a plate on the table such that the raised rear reference stop engages the raised rear reference portion on the plate, moving said table relative to said saddle so that the under surface of the head end of the plate will engage the outer surface of the saddle along a tangent thereto, and rotating said saddle circumferentially away from said table to pull the plate from the table.

5. A method according to claim 4 including the additional step of applying pressure to said plate in a radial direction with respect to said saddle while rotating said saddle and drawing said plate from said table to insure firm engagement between the saddle and plate.

References Cited UNITED STATES PATENTS 1,650,132 11/1927 Jones 101-426UX 2,668,363 2/1954 Lippitt 33 184.5 2,689,411 9/1954 Huck 33-184.5 2,736,259 2/1956 Sather 101378 2,900,735 8/1959 Mier 33184.5 2,901,832 9/1959 Hulen 33184.5 2,990,000 6/1961 Mangus et al. 101415.1UX 3,090,129 5/1963 Gifford 33184.5 3,158,943 12/1964 Benson 33184.5 3,206,859 9/1965 Walsh 33184.5

FOREIGN PATENTS 775,399 5/1957 Great Britain 10l426 ROBERT E. PULFREY, Primary Examiner C. D. CROWDER, Assistant Examiner US. Cl. X.R.

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