US3566784A

US3566784A - Squeegee device

Info

Publication number: US3566784A
Application number: US731549A
Authority: US
Inventors: Mathias Mitter
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-26
Filing date: 1968-05-23
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02
Also published as: CH472971A; NL6807373A; DE1760393A1; FR1565286A

Abstract

A squeegee device for stencil printing machines having rotary screens wherein the squeegee is arranged on the squeegee carrier movable towards the support. The squeegee is under the action of forces directed to the support and essentially distributed over the working breadth. The squeegee on the one hand and one element of the support on the other are working elements acting on each other by magnetic forces wherein at least one of the elements is magnetic and the other at least partially of magnetizable material. An ink pipe projects inside a rotary screen and the squeegee carrier is connected with the ink pipe. A slit open towards the support is provided in the squeegee carrier and the squeegee is adjustable in the slit.

Description

United States Patent Primary Examiner-Robert E. Pulfrey Assistant Examiner-Alan E. Koepecki AttrneyWenderoth, Lind and Ponack ABSTRACT: A squeegee device for stencil printing machines having rotary screens wherein the squeegee is arranged on the squeegee carrier movable towards the support. The squeegee is under the action of forces directed to the support and essentially distributed over the working breadth. The squeegee on the one hand and one element of the support on the other are working elements acting on each other by magnetic forces wherein at least one of the elements is magnetic and the other at least partially of magnetizable material. An ink pipe projects inside a rotary screen and the squeegee carrier is connected with the ink pipe. A slit open towards the support is provided in the squeegee carrier and the squeegee is adjustable in the slit.

[72] Inventor MathiasMitter Klagenfurt, Austria [21] AppLNo. 731,549 [22] Filed May 23,1968 [45] Patented Mar. 2, 1971 [73] Assignee Johannes Zimmer v Klagenfurt, Austria [32] Priority May 26,1967 [33] Austria [31] A4888/67 and A7591/67 [54] SQUEEGEE DEVICE 2 Claims, 1 Drawing Fig.

U.S.Cl 101/120 841113/06 FieldofSearch 101/123, 124,119,l20;118/(D&S);15/256.5l

[5 6] References Cited UNITED STATES PATENTS 764,275 7/1904 Dick 101/120X 1,264,506 4/1918 Hahn (118/D&S) 1,312,034 8/1919 Jones (ll8/D&S) 1,993,055 3/1935 Gerstenberg..... (ll8/D&S) 2,330,889 10/1943 Holcomb l5/256.51 2,695,004 11/1954 Montgomeryetal (ll8/D&S) 2,920,557 l/1960 Fuchs (ll8/D&S)

MATHIAS MITTER,

INVENTOR.

BYLOWMZJ;

stencil printing machines comprising rotary screens.

Squeegee devices particularly serve for regularly applying and/or distributing liquid, in particularviscous or pasty masses.

on surfaces which are only curved in one dimension,

preferably on material blankets or cylinders. However, 1

on the surface to be treated and another case inwhich the squeegee is pressed against a permeable screen, e.g. in screen printing, which rests on the surfaces to be coated or printed, e.g. on the material. a a

As to construction, there are two basic types of squeegees; the sliding squeegee on the one hand and the roller squeegee on the other; the latter. rolls off in relation to the surface to be treated or to the printing screen, .thusapplying the massif the case may be through the perforations of a printing screenon the surfaceto be treated. 1 I

In principle, the simplest solution lies in a roller squeegee which is magnetically attracted by a magnet body under the blanket; in this case only a cylindrical bar of magnetizable material is required which need not'be stored. It has been proved in practice, however, that, eg in stencil printing machines comprising rotary screens under specified working conditions, in the case of high printing speeds and upon the utilization of a printing ink of" high tenacity, the roller squeegee is shifted into the direction of movement of the screen wall or is deflected fro'mits position parallel to the screen axis or is even slightly bent. Thus the gap betweenthe roller squeegee and the magnet body under the blanket or material to be printed is increased while the magnetic attraction diminishes. Besides, the ink supply lying in front of the roller squeegee is augmented. As 'a result,'the printing quality is constantly had or. irregular. Similar phenomena are observed in other applications of rollersqueegees. These disadvantages are avoided in the sliding squeegee which is stationarily fixable but in the known devices comprising such sliding squeegees the mounting and adjustment of the sliding squeegee .require. considerable expenditure. Further,- more, it is very difficult to press the squeegee against the support by regular pressure over the whole working breadth.

erted do not act on the carrier, but directly on the squeegee.

In the device according to the invent on, the worklng edge of the squeegee automatically adjusts to the support and automatically follows possible variations of movement or thickness of the support without losing contact therewith and without exerting a strong braking effect on the parts movable in relation to each other. If the squeegee is ablade resistant to bending, the angle chosen between the blade-and the support is maintained, the thickness of the mass-applied depending on said angle. By arbitrarily rotating the squeegee carrier, said angle and the thickness of the mass applied can be arbitrarily modified, the squeegee blade automatically adjusting to the support upon each rotation of the carrier.

To movably arrange the squeegee on the carrier, it is convenient to provide a slit open towards the support in the carrier, the squeegee being adjustable in said slit.

The required force acting on the squeegee can be obtained with the'squeegee.

Another convenient. solution consists in that the squeegee on the one hand and one element .of the support on the other are working elements acting on each other by magnetic forces,

In the FIG. 1 a device for a stencil printing machine com- I prising rotary screens is shown. The ink pipe 19 through which desired means.

It is .commonly. known that a squeegee blade rigidly mounted on a carrier resistant to bending, the squeegee bar,

presses more strongly against the support in the marginal zones than in the medium zone if the forces by which the squeegee is generally pressed against'the' support, act on the extremities of the squeegee bar. a 7

Therefore squeegee blades havi'n'g curved working edges are generally used which become linear by the action of the exerted forces acting on the extremities of the squeegee bar. However, it is very difficult to produce squeegee blades having an appropriatelycurved working edge, e-.g. by sharpening or curving by means of a system of puller screws.

It is an object of the invention to create a device comprising a sliding squeegee having a simple construction which is easily adjustable and guarantees a pressure as regular as possible of the squeegee blade on the support, irrespective of possible deflections of the squeegee carrier.

According to the invention this is obtained in that the squeegee is movable on the carrier toward the support and that the squeegee itself is under the action of forces directed to the support, regularly distributed over the working breadth. It is obtained according to the invention that the working edge of the squeegee, preferably shaped like a blade, exerts a regular pressure on the support over the whole working breadth, irrespective of possible deflections of the squeegee carrier, because, according to the invention, the forces ex- The support over which the material 13 to be printed is led by means of a blanket 12, is a magnet bar 23 which attracts the squeegee blade 4; thus the working edge of the blade is pressed against the screen inwall. A magnet roller can also be applied as a support instead of a magnet bar.

A device for controlling the level of the printing ink is joined to thesqueegee carrier 21 whose electric tracer 24 is connected with the electric control of the ink supply through a cable 25.

As can be seen in the FIG. 1, the working element of the squeegee need not necessarily have the form of a flat sheet, but it can also be a prismatic body and even a round bar which is adjustable on the squeegee carrier movably towards the support.

lclaim:

l. A squeegee device for a stencil printing machine comprising a rotary screen mounted in said machine, a support for the material to be printed cooperatingwith said screen, a squeegee carrier located within said screen, a squeegee slidably mounted in said carrier and movable towards said support, said squeegee being under the action of forces directed towards said support and essentially distributed over

Claims

1. A squeegee device for a stencil printing machine comprising a rotary screen mounted in said machine, a support for the material to be printed cooperating with said screen, a squeegee carrier located within said screen, a squeegee slidably mounted in said carrier and movable towards said support, said squeegee being under the action of forces directed towards said support and essentially distributed over the working breadth of said squeegee, an element of said squeegee and an element of said support coacting on each other by magnetic forces, one of said elements being magnetic and the other at least partially of magnetizable material, an ink pipe projecting inside said rotary screen and said carrier being connected to said ink pipe.

2. A squeegee device according to claim 1 wherein said squeegee carrier has a slit open towards said support and said squeegee is mounted in said slit.