US2245828A - Machine for stenciling - Google Patents

Description

June 17, 1941.- J SCHUH 2,245,828

MACHINE FOR STENCILING Filed Sept. 23, 1938 Patented June 1.7, 1941 UNITEDTQSTAT'ES LPATENT oFFIcE MACHINE FOR STENCILING V Arthur J. Schuh, Wollaston, Mass.-

Application September 23, 1938, Serial No. 231,356

12 Claims.

The present invention" relates to-machines for performing by commercial methods a-process of plateless .printing by the use of stencils, and more particularly to means for improving existing poweroperated type printing presses of commercial design, so that plateless printing operations may be performed. thereon without departing from well-accepted printing press practices.

The object of the present invention is to provide a form of construction adapted for a type printing press of commercial design, so that impressions of a quality closely resembling the best off-set or plate work may be accomplished by an unskilled workman, without the use of plates or other expensive equipment, within a much shorter time than ordinarily required for such work. Other objects are generallyto simplify and improve the construction of a stenciling machine. The features of the inventiomwhile being effective for black-and-white work, are of particular advantage with work requiring a series of superimposed or separated impressions of different colors, and certain features are not limited exclusively to stenciling operations, but have been employed with good'results in connection with printing presses of commercial design when type or plates are use-d.

According to present day methods of stenciling, the application of ink or other coloring pigment to a work sheet through the cut-out portions of is compressed against the stencil. brush is limited in most cases to hand work, and only particularly strong and rigidly constructed stencils may be used with a wiper as it is carried across the surface of a stencil in order to avoid injury to the stencil, so that this form of ink applicator is not well adapted for power uses where delicately formed stencils maybe employed. A resilient inking pad is the only type of applicator which can be utilized successfully in power driven press Work, since it is the only inking device which does not have a destructive influence on the stencil. However, an inking pad, in order to be sufficiently resilient to make a perfect, uniform impression throughout the cut-out portions of a stencil, is so soft that it will ordinarily expand laterally and spread out while in contact with the stencil unless special means are provided to prevent it. Such movement under pressure tends to strain both the pad and the marginal edges about the cut-out-portions of the stencil beyond the'po-int of rupture and may cause other difficulties in ink distribution. To avoid these difliculties it has been the practice to reinforce the edges of a resilient inking pad with a frame or binding, the frame serving to attach the inking padto the press.

When a frame or other binding is employed to restrain the lateral edges of a resilient inking pad suitable for use on a power-actuated press of commercial form, the presence of the restraining frame is likely to interfere with the operating parts of the press and stencil. Furthermore, in addition; to the expense of manufacture, the adaptability of an inking pad Whose edges are thus restrained is much more restricted when stencils of different sizes and shapes are employed. The restriction of a frame or binding is particularly objectionable whereit is desired to employ a number of separate ink applicators including pads having specially prepared surfaces for providing effects not-obtainable with the use ofa single pad. s 7

' In accordance with its objects, an impontant feature of the present invention includes the proa stencil is effected by means of a brush, a squee gee type wiper, or'a. resilient inking pad which The use of a vision of a homogeneous resilient material such as sheet rubber, for use as an inking pad to carry an evenly distributed layer of ink through outout areas of a stencil onto a work sheet in a power-actuated printing machine, the quality and dimensions of the material, and particularly the thickness, being such that the restraint of'a frame or binding about the lateral edges of the pad will be unnecessary, and in use the pad will not be restricted either as to the number employed with a single stencil or as to the particular configuration of a frame or binding. The pad may be shaped at its edges with any configtu'ation desired in order to conform with the cut-away portions in a stencil or for other purposes. With this arrangement, it is possible to so locate the pad or pads as to give the best transfer and dis;- tribution of ink on the work sheet with the particular stencil inuse according to well-known printing practices. As hereinafter illustrated, the sheet material from which the pad is made has a'gage or thickness much less than has been used heretofore for such purposestthe relatively thin gage of the material rendering it unnecessary to specially reenforce the edges of the pad against spreading under compression. As aresult, the pad may be secured by cement without tearing loose at the edges and without injury to the pad, and no special form of fastener, such as must be used with previous framed or bound inking pads of this nature are necessary.

In a power actuated type printing press of common design the space ordinarily occupied by the type in the press is deeper than is necessary for an inking pad or block made from material of the gage or thickness employed in the present invention. In connection with the feature of the invention just referred to, a solid, quickly removable backing plate or panel is employed as an inking pad carrier to fill up the space not occupied by the inking pad, and the carrier is shaped to fit the holding means for the customary type supporting chase ordinarily employed while printing. Thus the customary type supporting chase and the inking pad carrier may be used interchange ably without requiring the individual arrangement of the inking pad or pads for a particular stenciling job to be disrupted when the press isv to be adapted again for printing or when a new with different stencils are to be substituted for those in the press. I

Other features of the invention consist of certain novel and improved constructions, arrangements, and combinations of parts hereinafter described and particularly pointed out inthe,

claims, the advantages of which will be obvious to those skilled in the art. In the accompanying drawing illustrating the features, of the invention Fig. l'is a perspective view illustrating a printing press of commercial design embodying the present invention; Fig. 2 is a view in perspective of, a stencil-cutting board on which the stencils used in the press illustrated in Fig. 1 are prepared; Fig.

3 is a Sectional view taken along the line 3 .'-3 ofv Fig. 2 illustrating the finished shape of the stencil; Fig. 4 is a perspective view of an ink applicator employed in the press illustrated in Fig. 1; Fig. 5 is a perspective View ofa gripperarm.

adapted for use in the press and arranged to support the stencil; Fig. 6 is an enlarged sectional;

view, taken along the line 66 of Fig. 5, illustrating the means for fastening the stencil to; the

gripper arm; and Fig. '7 is a view in perspective of a modified form of gripper and stencil sup porting arm.

simplest manner in which to form a. stencil is to mount a transparent sheet of stencil material, as indicated at 2, over a paper 4 bearing an original configuration 6 whichis to be reproduced, so that by merely following the outlines visible through the stencil material with a stencil knife 8, the portions of the stencil covering the areas] It] for which an impression is to be made, areremoved with a perpendicular out. After impressing a suflicient number of work sheets.

through the cut-out portions of one stencil it frequently is desirable to out out the portions of a second stencil corresponding to other. areas of the configuration, so that a second color may-be applied to new areas in the set of work sheets originally impressed, the cut-out edges. of; theprinting bed l2 pivotally mounted at M on the main frame N5 of the press, ink distributing rolls H movable across the type bed, and a rocking work-supporting platen I8. The frisket frame ordinarily includes a gripper bar 20 and a pair of gripper arms 22, to which the stencil 2 is fastened. The gripper bar is pivotally mounted on the platen and is pressed yieldingly against the work-supporting face ofthe platen just before and somewhat after the impression is made. After each impression the platen isrocked to a position in which the gripper arms 22 are raised from its surface, as indicated in Fig. 1, so that the work sheet lying on the platen may be removed and a new one substituted. To locate each new WOIk sheet in the press the platen is provided with gage blocks 23 of the usual form, projecting from the surface of the platen.

Infitting a printing press for plateless printing work with stencils having relatively large cutout areas, the problem of uniform ink distribution throughout each area becomes extremely difiicult if an attempt is made to obtain with the use of a stencil, work which compares favorably with the best quality of plate printing work. The usual method of stenciling is to apply an excess of ink to an inking device and to employ an absorbing paper work sheet, forcing the excess ink through the cut-out areas of the stencil more or less by. hydraulic pressure, leaving irregular accumulations of ink on segregated portions of the Work sheet which limits the speed of impression to. the speed of absorption of the paper used. The ink may even be forced beneath the edges of the stencil around the cut-out areas, causing distortion of the design and improper registration of the inked areas with the other parts of the work I Also, where a. number of different stencils are. to beemployed successively, as when a number of differently colored inks are tobe impressed, careful adjustments are. necessary in order to insure that edges. of the cut-out portions in each successive stencilwill register with the edges of areas impressed with previous stencils. Since it 1.: is desirable to have a. registration of colors successively applied withan accuracy within a few second stencil being held in accurate registration with the edges ofareas already colored on. the work sheets where complementary impressions are desired.

To support the stencil, the; stencilmounted on the frisketframeof an; ordinary.

power-operated type printing press, such-asindi catedin Fig. 1, the press beingprovided witha hundredths of an inch, the adjustments required to obtainthis, accuracy frequently. require considerable kill and timefor their accomplishment. Accordi tothe; present invention, the stencil material is so supported: while: each. stencil is being out out that the'edges-of cut-out portions in successive stencils will register without complicated or time-wasting; adjustments,- certain. po-

.sitioning indications in the form of perforations being made in th stencil which are so located that they will; fit the spacings of. corresponding perforations formed; inthe; ripper arms of the press.

Referring to. Fig. 2;of the drawing theapaper 4- vided with perforations- 3.2; of. a. suitable size to,

receive slidably rod-like fastener devicespassing rou h h S d d es of r. the. stenciling material.

J Thegripperarms ofrthepress towhich the-stem- The board 26 has,

oil is secured after beingcut out are also formed with perforations spaced the same distance apart as the perforations in the arms 30, so that when thecompleted stencil is transferred to the .press, the edges of the cut-out portions of each new stencil will beara predetermined relation to the platen l8 of the press to which the gripper arms are connected. In order to insure an extremely accurate registration of each successive stencil after being cut out, the gripper arms 22 of the press may be removed from-the gripper .bar and bolted onto the positioningbar 28 of .the stencil ,board 26, in making. a stencil. If a stencil .is cut out while the material is attached to these gripper arms, the arms may then be removed, together with the stencil, without discon necting the stencil from the arms, when applied to the press. ToJpermit this method of procedure the positioning bar 28 of the stencil board is madeof substantially the same size and shape as the gripperbar 20 of the'press, so as to'fit interchangeably with the gripper arms 22 of the press or the arms of the stencil board. After applying the stencil to the press, additional openings 3| may be found to be'essential in the stencil to prevent the gage blocks 23 from striking thematerial of the stencil so as to injure or dis tort it.

To apply the stencil material to the arms 30 of the stencil-cutting board, a section of the stencil material is temporarily held as by wire clips 34 (Fig. 4-) or other suitable means, to the arms 30. Perforations are then made which register with theperforations of the bar or the stencil material may be furnished with perforations fitting those of the bar, and the rod-like fastenersapplied to the registering perforations. The fasteners illustrated in Fig. 6 are in the form of conventional flat head-ed split rivets, the shanks of which fit closely within the perforations, the split portions being of a sufiiciently yielding nature to frictionally secure the fasteners in place. Fasteners of this type are particularly effective in that the heads of the fasteners are of minimum thickness while providing sufficient areaof contact with the stencil material to support it an uneven surface or when, due to slight curva-' ture of. the armsthere isa slight tendency for the stencil material to draw away from the arms. As 'a result, there will be no substantial strain imparted to the stencil material when pressure is applied, but the fasteners will be withdrawn slightly from the perforations in the arms to permitthe necessary movement. Similar fasteners are used to secure the completed stencil to the gripper arms 22 of the press, it being equally desirable to permit the stencil to separate slightly from the gripper arms while at the same time the stencil is maintained securely from movement along the gripper arms.

Referring to Fig. 7, a modified gripper arm 31 is provided having rod-like fastener devices, in the form of pins 38, permanently mounted in the arms. To hold the stencil on the pins, a spring strip 39. is secured at its lower end to the arms, and. perforated to receive the pins 38 so that when the perforated stencil i applied to the pins the strip 39 will act yieldingly to hold it in place. A convenient means for locking the strip consistsiof .a rectangular sleeve 40 shaped to slide over...theupper..end of the .arm and engage an offset .tab on .the strip.v ,To avoid making the sleeve. 40 of greaterthickness than the spaces in the press will permit, the tab at the end of the strip .39 fits within an opening in the upper end of the arm so as to lie in the same plane with the arm. With this form of fastener device, the sheet of. stencil material may be perforated by forcing the. stencil sheet against the pins by pressure on the strip 39, the pins and the perforations in the strip :acting as punches for the stencil sheet.

- .The. inkapplicatorfor the press of the present invention comprises one or more sections or blocks 42 ofthin'homogeneous sheet rubber material of medium resiliency secured by cementing at various selected locations on the surface of a carrier in theformof a wooden plate or panel 44. Each .Jblock preferably isarranged to conform roughly with a cut-out area in the stencil. The panel 44 is shapedto fit tightly within the clampingframe of, the press bed [2, being shaped with bevelled edges-and corners to cooperate properly with the clamping means of the frame, one of which is indicated at 46, and comprises a handoperated hook which\releasably presses against one of the bevelled edges of the panel. The clampingmeans of the frame which ordinarily supports the type-holding chase of the press remains without change so that the panel 44 may be used interchangeably with the standard type chase. To prevent injury to the corners andportions engaged by the clamping means of the clamping .frame, the edge and corners of the frame are suitably reinforced by metal inserts 48 secured with their surfaces flush with the surfaces of the panel. The material for the ink applicator blocks should preferably not be greater than onequarter inch in thickness for the best results, and when of this thickness, the rubber must have a rigidity which will require an extremely heavy pressure to cause it to enter the cut-outs of the stencil. The applicator block itself carries the ink previously distributed by the inking rolls on the surface of the block, through the stencil and into direct con-tact with the blank work sheet at the opposite side of the stencil. By so doing, the uniform thin layer of ink distributed on the block by the rolls is preserved during application 1 to the work sheet. This operationis distinguished made, there is substantially no expansion or.

spreading out of theblocks about their lateral edges, and no reinforcement of any kind is required. Ordinary rubber cement is sufficient to hold. 'theblocks in place, and the positions of. the blocks may be chosen in a manner which will provide the best distributionof ink upon the work sheet being operated upon. The use of rubber cement also renders the blocks readily removable i and replaceable without special equipment. The

shapes of the blocks are also easily changed so as to conform in a better manner than heretofore considered possible, with the shapes of the cut-out areas of a stencil and blocks of smaller area maybe used, permitting an arrangement of block to give special efiects resembling the finest quality of plate work as will be hereinafter described. Also, by employing a smaller block, a heavy application of ink to portions of a stencil not cut out is avoided, and the edges around the cut-out areas may be acted upon by a very small overlapping portion of the corresponding ink block.

According to this feature of the invention, an inexpensive and simple method of producing half-tone or so-called Ben Day effects is possible. Suitable areas of a stencil may be cut out and instead of utilizing an inking block having a plain smooth surface, a block, such as indicated at 49, of the proper shape to clear the smooth blocks 42 may be employed. The surface of the block 49 is formed with fine parallel lines, as shown, or with cross lines, or with other suitable figure to produce the appearance desired. Thus, it is possible, by simply providing ink block material having different surfaces, to produce results equalling in quality those obtainable heretofore only with expensive plates.

Also, in connection with this feature of the invention, it may be desirable to employ an entirely separate block similar to the block 42, but located at a position opposite a solid portion of the stencil to act in distributing the ink to better advantage. Even where type or plates are used in the press, a small block of rubber which will be covered by a shield of stencil material secured to the gripper arms is desirable where difiiculty is bad with shadow effects from imperfect ink distribution by the inking rolls IT.

The stencil is composed of ordinary thin sheet celluloid material having one side 50 glazed, as indicated in Fig. '7, and the other side 52 frosted or roughened. The method of making the stencil comprises fastening a sheet of stencil material to the underside of the arms 30 so that the glazed surface 50 will contact the paper bearing the original configuration with the frosted surface uppermost. The stencil cutting knife 8 may be operated to form a cut at right angles to the surface of the stencil material. Not only is a sharper definition of the original configuration visible for cutting on the frosted surface 52 of the stencil material when applied in this way, but also it is easier to manipulate the stencil-cutting knife and a more accurate outline is thus obtainable. After forming the cut-out openings in the stencil, the angular edges at the upper frosted side are bevelled while the edges at the lower glossy side are left as sharp as possible, as indicated in Fig. 7. By providing bevelled edges at the frosted side, damage due to cutting the inking surfaces of the blocks 42 is avoided and the ink carried by the blocks is not collected along the edges to such an extent as to form heavy margins in the impression made. The frosted surface 52 also assists in holding the ink carried by the inking pad during the formation of an impression, so that it will not be forced into the angle formed by the edges of the cutout portions in the stencils to such anextent as occurs if a glossy surface engages the ink. block. Another advantage of the frosted surface 52 is that the tendency of adhesion between the ink block and the stencil during rapid impress'ion. in a power-operated press is substantially reduced. a r

In order to obtain a satisfactory ink distributionover the relatively larg areas ordinarily impressed where the use of stencils is made, the visoosityof type printing ink is too great, and the adhesion betweenthe ink blocks and the stencil. with the use of such ink is prohibitive. It: is, therefore, desirable to thin the ink with a suitable solvent, thus rendering impractical the common methods of ink mixture with the use of a spatula or knife- Particularly where several different. colors are impressed upon the work sheet, it is desirable to obtain the proper matching. of colors and, accordingly, an ink-mixing method, including the use of a measurement by drops, may be used to advantage. In such a method. of ink mixture, certain basic colors may be supplied. in suitable. containers having spouts which render the drop-measurement method more effective. It has'been found that an ordinary oilcan having a spout in the usual form is convenient for such color mixing or matching.

The nature and scope of the invention having been indicated,.and a method andconstruction embodying the several features of the invention having been specifically described, what is claimed is:

1. A power operated press adapted for stencil work having, in combination, a printing bed, a work holding platen mounted for movement towards and from the printing bed, stencil supporting means between the bed and the platen, a clamping frame on the printing bed for releasably retaining a type chase, and an ink applicator on the printing bed comprising a resilient inking block and a wooden carrier shaped to fit and be retained interchangeably within the clamping frame, said carrier having a fiat supporting surface to which the inking block is cemented. and metallic inserts along those portions engaged by the clamping frame.

2. A power operated press adapted for stencil work having, in combination, a printing bed, a work holding platen mounted for movement towards and from the printing bed, stencil supporting means between the bed and the platen, and a number of laterally unrestrained blocks of homogeneous resilient material on the bed, at least one block having a figured surface for forming ink impressions through the cut-out portions of a stencil on a flat work sheet on the platenvto resemble a half-tone cut. a

3. A power operated press adapted for stencil work having, in combination; a printing bed, a work holding platen mounted for movement towards and from the printing bed, stencil supporting means between the bed and the platen, a block of homogeneous resilient material having a smooth ink applying surface to form solid ing impressions through certain cut-out portions of a stencil on a flat work sheet on the platen, and a block of similar material having a figured surface for forming a half-tone impression through other cut-out portionsof the same stenoil.

7 4. A power operated press having, in combination, a printing bed, type on the printing bed, a work holding platen mounted for movement towards and from the. printing bed, ink distributing rolls, movable across the type, a shield, shield supporting 'meansbetween the bed and theplaten, and a block of resilient material on the bed opposite the shield for acting with the ink rolls to improve the ink distribution.

5. A power operated press adapted for stencil work having, in combination, a printing bed, means on the bed for supporting a stencil inking block, a work holding platen mounted for movement toward and from the printing bed and stencil supporting mean comprising a gripper bar, means for actuating the gripper bar, substantially parallel gripper arms on the gripper bar provided with rod-like fastenings arranged to engage perforations in and prevent displacement of a stencil along the arms, and means in cluding the fasteners for securing the stencil yieldingly in the plane of the arms.

6. A power operated press adapted for stencil work having, in combination, a printing bed, means on the bed for supporting a stencil inking block, a work holding platen mounted for movement toward and from the printing bed and stencil supporting means comprising a gripper bar, means for actuating the gripper bar, substantially parallel gripper arms on the gripper bar provided with rod-like fastenings arranged to engage perforations in and prevent displacement of a stencil along the arms, and spring strips on the arms for securing the stencil yieldingly in th plane of the arms.

7. A power operated press adapted for stencil work having, in combination, a printing bed, a work holding platen mounted for movement towards and from the printing bed, stencil supporting means between the bed and the platen, means for forming an ink impression, a stencil on said supporting means having certain areas cut away and a frosted surface at that side of the stencil engaged by the impression means to assist in distributing the ink.

8. A power operated type-printing press fitted for rapid impression stencil work according to accepted type printing press practices and provided with a printing bed, a work holding platen mounted for relative movement towards and from the printing bed, a stencil support between the bed and platen on' which is mounted a stencil having cut-out areas of relatively large size, ink distributing means, and ink carrying means along the surface of which the distributing means acts, comprising laterally unrestrained blocks of resilient material on the bed opposite the cutout stencil areas having a thickness and a consistency which causes uniform application of ink to a work sheet by forcing the inked surfaces of the blocks through the cut-out areas of the stencil into accurate registry against the work sheet without causing substantial spreading out of the blocks along the surfaces against which it is pressed or requiring the use of ink having relatively great viscosity.

9. A power operated type-printing press fitted for rapid impression stencil work according to accepted type printing press practices and provided with a printing bed, a work holding platen mounted for relative movement towards and from the printing bed, a stencil support between the bed and platen on which is mounted a stencil having cut-out areas of relatively large size, means for distributing ink having relatively low viscosity as compared to that used in accepted type printing practice, and ink carrying means along the surface of which the distributing means acts, comprising laterally unrestrained blocks of resilient material on the bed opposite the cut-out stencil areas, the rigidity of which material require a heavy pressure to cause it to contact a work sheet with accurate registry through the cut-out areas of the stencil and the thickness of which is insufiicient to cause substantial spreading out of the block about their lateral edges when pressed against the sheet.

10. A power operated type-printing press fitted for rapid impression stencil work according to accepted type printing pres practices and provided with a printing bed, a work holding platen mounted for relative movement towards and from the printing bed, a stencil support between the bed and platen on which is mounted a stencil having cut-out areas of relatively large size, means for distributing ink having relatively low viscosity as compared to that used in accepted type printing practice, and ink carrying means along the surface of which the distributing means acts, comprising laterally unrestrained blocks of resilient material on the bed opposite the cut-out stencil areas, the rigidity of which requires heavy pressure to cause it to contact a work sheet with accurate registry through the cut-out areas of the stencil, and the thickness of which is not substantially greater than onequarter of an inch to prevent spreading out of the blocks about their lateral edges when pressed against the sheet through the stencil.

11. A power operated type-printing press fitted for rapid impression stencil work according to accepted type printing press practices and provided with a printing bed, a work holding platen mounted for relative movement towards and from. the printing bed, a stencil support between the bed and platen on which is mounted a stencil having cut-out areas of relatively large size, means for distributing ink having relatively low viscosity as compared to that used in accepted type printing practice, and ink carrying means along the surface of which the distributing mean acts, comprising one or more laterally unrestrained blocks of resilient material on the bed opposite the cut-out stencil areas, the rigidity of which material requires a heavy pressure to cause it to contact a work sheet through the cut-out areas of the stencil and the thickness of which is insufficient to cause substantial spreading out of the blocks about their lateral edges when pressed against the sheet, said blocks being shaped and disposed to provide only a small portion about their edges overlapping the edges of the cut-out areas of the stencil.

12. An ink pad for rapid impression use with a cut-out stencil on a power operated mechanical press designed for type printing work according to accepted type printing practice comprising a laterally unrestrained block of homogeneous material of such thickness and consistency that, when a surface of the block carrying a thin layer of ink is pressed through the cut-out areas of a stencil against a work sheet, uniform distribution of ink is obtained along the surfaces of the work sheet without causing substantial spreading out of the block due to pressure.

ARTHUR J. SCHUH.

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