US2384626A

US2384626A - Matrix guide

Info

Publication number: US2384626A
Authority: US
Publication date: 1945-09-11
Anticipated expiration: 1962-09-11

Description

Sept. 11, 1945. G. J. KOCH ETAL MATRIX GUIDE Filed July 8, 1944 GEORGE J. KOCH ROGER P. LEAVITT INVENTORS Wflfiw BY ATT'Y & AG'T N m A L m :3 1 6 2 KM, 5 /1 4 Z Z FL 2 2 G H x Patented Sept. 11, 1945 UNITED STATES PATENT OFFICE MATRIX GUIDE Application July 8, 1944, Serial No. 544,078 7 4 Claims.

This invention relates to printing devices particularly to pressure applying mechanisms for use in processes in which printing ink or other medium is transferred from two matrices simultaneously to opp site sides of a sheet.

Such processes include vectographic printing in which'the vectosensitive material receives the appropriate ink from flexible wash of! relief matrices between which it is sandwiched. It is the object of the invention to provide a suitable guiding device so that the sheet to be printed, such as the vectosensitive material, can be fed between the matrices to make contact therewith only as the sandwich reaches the point at which pressure is applied or at least just before it reaches this point It furthermore is the object of the device to prevent the inked up matrices from touching the sheet material at any time prior to the desired contact and thus to insure accurate and precise printing.

It is an object of one embodiment of the invention to provide means for holding the upper matrix out of the way, without marring this-matrix and without applying any harmful degree of tension thereto.

It is an object of one embodiment of the invention to provide convenient clamp means for holding the two matrices in register so that a succession of prints may be made therefrom without incurring the possibility of lack of register between the images on the two sides of the sheet. With such an arrangement, a preferred embodiment of the invention has the guide mechanism so arranged that it may be quickly moved to one side while the matrices are arranged to receive the sheets to be printed.

According to the present invention the above advantages are gained in a duplex printing device by having a pair of pressure rollers resiliently urged toward each other and with some driving means so that the whole device may be used for sandwiching the sheet between the printing matrices. A table is provided for supporting the lower matrix as the lead edge of the sandwich is fed between the rollers and means are provided for holding the upper matrix out of contact with the lower one except just before they reach the pressure rollers. Between the two matrices there are located two guides at fixed separation between which the sheet to be printed is loosely fed and the lead edge of the sheet engages the two matrices to form the sandwich just as it reaches the pressure rollers. These guides insure against contact between the sheet and either matrix prior to the formation of the sandwich.

In a preferred embodiment of the invention a roller holding the upper matrix lightly against the upper one of the pressure rollers constitutes part of the means for holding the matrices separated. The advantage of this feature is the fact that the upper matrix is fed by this pressure roller outward toward the rest of the sandwich forming system at exactly the same speed as the sandwich as a whole is fed through the pressure system which insures that the loop or slack portion in the upper matrix remains constant throughout the printing cycle. Preferably the lower matrix rests on a rigid plate and the lead edge of the matrix sandwich is secured to this plate by a clamping bar which passes, during the printing cycle, between the pressure rollers pulling both matrices, and between the matrices the printing sheet, with it. The matrices can be inked up without being removed from this rigid plate which insures maintenance of registration of the matrices from one print to the next and then the matrices can be quickly mounted in position to receive the print sheet. To render this operation even more convenient, the print sheet guides are hingedly arranged on the apparatus so that they may be swung to one side while the matrices are placed in position and then brought back between the matrices to guide the print sheet during the printing cycle.

The invention will be fully understood from the following description when read in connection with the accompanying drawing in which:

Fig. 1 is a perspective view of the preferred embodiment of the invention.

Fig. 2 is a side elevation partly in cross section of the arrangement shown in Fi 1.

In Fig. 1 two printing matrices l0 and ii are clamped to a steel plate H by a clamping bar l3. The edge provided by the clamping bar l3 constitutes the lead edge of the matrix sandwich which is to be fed between pressure rollers I1 and I8 resiliently urged toward each other by springs in the usual way but not shown, the pressure being adjusted by means of hand screws IS. The edge of the clamp bar I3 is beveled so as to pass easily between the pressure rollers I! and I8. Rotation of the rollers is provided by a handle l9 and suitable gears which may be of the usual type but which are preferably arranged as described in the copending application Serial No. 544,077 of one of us (Leavitt) filed July 8, 1944, concurrently herewith.

As the matrix sandwich is fed to the pressure rollers, the plate I2 and the lower matrix 10 are supported by a table H. The upper matrix H is folded back over the roller I1 and held in contact therewith by a wheel 20 lying lightLv thereon, the pressure supplied by a spring 2| being just suflicient to hold the matrix II firmly against the rolls" I'l without damaging the matrix in any way. am. the matrices Ill and II have been inked up they are placed in the position shown in Figs. 1 and 2, a handle 22 being provided for raising the roller wheel 20 while the matrix II is brought into place. It will be noticed that as the matrix sandwich is fed between the rollers I1 and I8, the rotation of the roller I'l simultaneously feeds the upper matrix I I past the roller 20 at the same speed as this matrix II is passed between the rollers I1 and It so that the loop formed by the matrix I l stays the same size.

While the inked up matrices are being thus arranged,

guides

25 and 26 for the print sheet are positioned to one side, as shown by broken lines 30 in Fig. l. The

guides

25 and 26 carried by

end pieces

21 and 29 are then turned on hinge 28 to the position shown in both Figs. 1 and 2. The sheet 24 to be printed is then fed loosely between the

guides

25 and 28 which are at fixed separation so as not to bear on the print sheet 24 or on either matrix III or II. The guides 25 prevent the sheet 24 and the lower matrix I coming into contact and the guide prevents the loop of the upper matrix II from touching the print sheet 24. This whole arrangement insures that the matrices I0 and l I engagethe print sheet 24 only immediately before the whole sandwich enters the pressure area provided by the pressure rollers I1 and I8.

Repeated operation of this mechanism is quite convenient and yet the absolute registration between the images provided by the matrices I l and I I is not disturbed.

Having thus described the preferred features of our invention we wish to point out that it is limited in scope only by the following claims.

What we claim is:

l. A duplex printing device for use in a process in which printing medium is tranferred to both sides of a sheet simultaneously from two flexible matrices fastened together at the lead edge, comprising a pair of pressure rollers resiliently urged toward each other, means for driving the rollers in opposite directions for sandwiching the sheet between the matrices, a table to support the lower matrix as the lead edge is fed between the rollers. means for holding the upper matrix out or contact with the lower one except as they reach the pressure rollers and two guides above the table and at fixed separation between which said sheet is loosely fed to the matrix sandwich for insuring a ainst contact between the sheet and either matrix prior to reaching the pressure rollers.

2. A device according to claim 1 in which the means for holding the upper matrix is a rolling member lightly urging the upper matrix toward the upper one of the two pressure rollers whereby the upper matrix is fed to the sandwich at approximately the same speed as the sandwich is fed between the rollers.

3. A device according to claim 1 in which a rigid plate is included on the table including clamping means for the lead edge and forming part of the sandwich which passes between the pressure rollers.

4. A device according to claim 1 in which the two guides are hingedly mounted on the table to be swung to one side as the matrices are set in place and to be swung between the matrices to be in place to guide the sheet being printed.

GEORGE J. KOCH. ROGER P. LEAVITT.