US2881698A - Screen process printing machine - Google Patents

Description

' April 14, 1959 EIJJGRAHAM 2,881,698v SCREEN PROCESS PRINTING MACHINE Fileq Ju1y'19, 1956 I 2 Sheets-Sheet 1 INVENTOR. i J4 E. Jmm Emma.

BY I

A TTOKMF) April 14, 1959 E. J. GRAHAM- 2,831,598

SCREEN PROCESS PRINTING MACHINE Filed July 19, 1956 I 2 Sheets-Sheet 2 IN VEN TOR.

I TTOKNEY' E. Juan ERAHAM v United States Patent SCREEN PROCESS PRINTING MACHINE Eugene John Graham, Havertown, Pa., assig'uor to Kenn Equipment Co.

Application July 19, 1956, .Serial No. 598,885

3 Claims. (Cl. lob-12?!) My invention relates to a screen process printing 'machine and, more particularly relates to a paint distributing and collecting device for such a printing machine.

The silk screen printing process utilizes a sheet of fabric screen which is stretched tightly upon a frame and has a stencilled portion through which paint may pass to form the design. Paint in a semi-liquid state is placed upon the stencil or screen at one end and is drawn over the stencil in a wave by a squeegee scraper. The paint thus drawn over the stencil fills the open pores of the pervious design portion of the stencil and adheres below.

Since the class of work turned out by apparatus of this description competes with vari-color work produced by the lithographic process, it is important, in order to keep down the cost of production, that the prints be made at a comparatively rapid rate. However, where highly detailed, multi-colored work is required, it has been found that the squeegee can only be drawn over the stencil in one direction only, for otherwise the stencil screen would be drawn in two directions and cause inaccurate registration of the various colors.

It, therefore, is an object of my invention to provide a squeegee device for a screen process printing machine for evenly spreading ink or paint upon the stencil screen with means to carry back the surplus thereof after traverse in the direction, above the screen to the initial printing stroke position.

Another object of my invention is to provide a screen process printing machine that will afford highly accurate registration of the various colors printed by the use of different stencils.

Another object of my invention is to construct a screen process printing apparatus wherein the paint or ink will stay exactly where impressed upon the paper that receives it.

Another object of my invention is to provide a screen printing machine wherein the excess paint will be automatically scooped up at the end of the printing stroke.

Another object of my invention is to provide a screen process printing machine wherein the ink will be automatically deposited and distributed upon the screen in front of the squeegee immediately at the beginning of each printing stroke.

Other objects of my invention are to provide an improved device of the character described, that is easily and economically produced, which is sturdy in construction, and which is highly efficient in operation.

With the above and related objects in view, my invention consists in the details of construction and combination of parts, as will be more fully understood from the following description, when read in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a screen process printing machine having automatic collecting and depositing means embodying my invention.

Fig. 2 is a rear perspective view of the automatic collecting and depositing means together with its assembly upon a squeegee blade.

Fig. 3 is a sectional view of-the collecting and depositing means.

Fig. 4 is an end view of the collecting and depositing means in position against the squeegee blade immediately prior to lowering it against the screen surface.

Fig. 5 is an end view of the collecting and depositing means in position against the squeegee blade as the squeegee first makes contact with the screen.

Fig. 6is a-n end'view of the collecting and deposit-ing means in position with respect to the squeegee blade during the normal printing stroke.

Fig. 7 is an end view of the collecting and depositing means with respect to the squeegee blade as the termination of the print-ing stroke has occurred.

Fig. '8 is-a'n'end view of the collecting "and depositing means with respect to the squeegee blade as *the squeegee is about to be returned to its initial starting position.

Referring now in greater detail to the drawings, in which similar reference characters refer to similar parts, I show a screen process printing machine comprising *a table, generally designated as A, a conventional screen printing frame assembly, generally designated as B, a squeegee stroke assembly, generally designated as C, and

an automatic scoop device hingedly mounted thereon,

and generally designated as D.

The printing table A is of conventional design having a surface top 10 supported upon four legs 12. It is upon the surface top 10 which the printing material 1 4 is placed directly below the screen frame B.

The screen frame B is affixed immediately below 'a metal ballast frame 20 by a plurality of downwardly extending lugs secured to the latter. The-metal frame 20 is hingedly affixed -'to the rear of the table top 10 by pin hinges '22 and suitable ballast (not shown) is provided at the rear of the print ing table A to facilitate the hinged operation of the screen frame B when it is desired to change the printing stock 14. The frame B is stretched thereon at its lowermost portion the usual silk or metal screen 18 which carries the stencil for forming the design to be printed.

The squeegee stroke assembly C comprises a lever arm 24 which is slidably and hingedly supported upon a traverse rail 26 which extends the entire length of the rear of the table surface 10 and mounted thereon at each end by a post 28. A bracket 30 is slidably mounted upon the lever arm 24 whereupon slight adjustments in the lateral direction of the squeegee may be made by loosening adjusting screws 32. The bracket 30 extends the entire width of the printing frame and is also pivotally mounted at 34 along a longitudinal axis in order to provide complete freedom of rotation about that longitudinal axis whereby the weight of the squeegee assembly may be distributed laterally within the printing frame by virtue of its own weight. This enables distribution of ink 36 placed in front of the squeegee as its stroke is carried longitudinally across the top of the stencil 18 in the form of an even wave without excess pressure being exerted upon either end of the squeegee. The bracket 30 has at its lower portion thereof, a channel 37 to accommodate therein a squeegee plate 38, the latter being locked into adjustable vertical position within the bracket 30 by a pair of locking screws 39 extending from the lowermost portion of the bracket.

The squeegee blade or scraper 40 is mounted upon the bottom of the squeegee plate 38 between an intergral flange 41 extending from the lower portion of the blade and a removable rear flange 42 which is secured to the blade by a plurality of mounting screws 44.

The automatic scoop D is hingedly supported upon the squeegee assembly C at each end of the plate 38 and comprises an arcuate pan 46 aflixed at each end to a side plate 48, the latter having a construction resembling a -rails"56 secured within the printing frame B and longitudinally extending therein. The guide rails 56 terminate at a point 58 corresponding to the end of the printing stroke. It is at this point 58 wherein no support for the guide rollers 54 will'be provided and thereby causes the scoop D to drop about its pivotal position 52 and efiect the entrapment of the wave of ink 36 between the bottom end of the pan 46 and thesqueegee blade 40.

Looking of the scoop D against the squeegee blade 40 is accomplished by providing a notch 60 at the front end of each of the side plates 48 which engage a support pin 62 mounted in the end of the plate 38 when the scoop D is in collecting position.

As is apparent from the foregoing description, a wave or puddle of ink is disposed immediately in front of the squeegee blade 40 at the beginning of the printing stroke. The squeegee assembly C is gravity actuated and has sufiicient weight to insure firm contact of the squeegee .blade 40 as it is longitudinally carried across the screen 18 by hand operation of the lever arm 24. The wave- 7 of ink 36 is evenly distributed through the pores of the stencil 18 since the scoop D is forced open by the action of its rollers 54 bearing upon the guide rails 56. At the end of the printing stroke, the scoop D will drop into engagement with the front of the squeegee blade 40 since support for the guide rollers 54 is terminated at the end of the rail. 'Accordingly, any slight further movement longitudinally of the squeegee assembly C will cause the excess ink at the end of the stroke to be firmly entrapped between the scoop pan 46 and the front ofthe squeegee blade 40. Thereupon the pivotal raising of the lever arm 24 which is facilitated by ballast weight 66 at its rear end, will completely free the surplus ink from the terminal end of the stencil 18, and enable this ink to be carried back to the beginning of the printing stroke as the squeegee assembly is carried back to its initial point. As the squeegee assembly C is once more lowered at its initial point, this surplus ink will be deposited at the be ginning of the screen since the guide rollers 54 once more engage the guide rails 56 and effect depositing of the ink therefrom.

Although my invention has been described in considerable detail, such description is intended as being illustrative rather than limiting, since the invention may be variously embodied, and the scope of the invention is to be determined as claimed.

I claim as my invention:

1. In a screen process printing machine having a printing frame hingedly supported upon a table and a squeegee assembly'hingedly secured to and longitudinally'slidable on the table, a wiper element aflixed to the lower portion of said squeegee assembly, a scoop pivotally and eccentrically slidable on said squeegee assembly, and rail means on said printing frame for engaging and maintaining said scoop in open position during printing stroke and gravity means to close said scoop at the endof the printing stroke.

2. The invention of claim 1 wherein pins on said squeegee assembly are in pivotal and slidable engagement with slots in said scoop.

3. The invention of claim 2 wherein rollers at the ends of said scoop are adapted to engage the upper surface of said rail means. 4

References Cited in the file of this. patent UNITED STATES PATENTS 1,687,080 Beck Oct. 9, 1928 1,966,416 Parmele et a1. July '10, 1934 2,746,084 Podgor Sept. 25, 1956

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