US1979735A - Printing - Google Patents

Description

Nov. 6, 1934.

J. ELMER ET AL PRINTING Filed Jan. 18, 1933 INVENTORS Jamv fLJljff? A OR Patented Nov. 6, 1934 UNITED STATES AT T cries PRINTING Application January 18, 1933, Serial No. 652,346

2 Claims.

This invention relates to a method of making blocks for block printing. More particularly, the invention relates to a method of making a Wooden block having lines or pins formed thereon by saw cuts, and with portions cut away so as to leave only those parts of the pins or lines which correspond to design areas upon which it is to apply a particular paint, or which it is desired to treat, as in a mashing operation, by burning transverse grooves through the Wood of the lines or pins. In referring herein to printing blocks, or print-blocks, we include special blocks, e. 'g., so-called mash blocks, as well as those blocks which actually apply the paint or color.

Blocks of the general type referred to above are commonly used, for example, in the printing of paint-coated felt base goods, printed linoleums oil cloths and the like. In the manufacture of these blocks, it has been customary to form the designs by cutting away portions of the lines or pins with a sharp chisel. At best, this is a very delicate operation. It frequently happens that the strain produced by the wedging action of the chisel breaks away portions of the line or pin which should have been left intact, and it is then necessary to replace these broken portions by brass pins, or other means, with considerable loss of time, and in some cases with some impairment of the quality of the block for printing purposes. Particularly in the case where narrow portions of the lines or pins are to be left for the application of relatively small drops of paint, it is extremely difficult to cut away adjacent portions without injuring the part which is to be left intact. If it is broken away completely, it must be replaced with a brass pin, as described above, whereas if it is not broken away, but is cracked, it may be even more serious, because the defect may not appear until the block is on the machine, whereupon the slight additional strain imposed in the printing operation may be sufiicient to break the piece away from the block.

It is an object of the present invention to provide a method of cutting blocks such that even extremely fine projections may be formed for the carrying of small drops of paint with little or no danger of injury. It is another object of the invention to provide a method for cutting such blocks which not only will result in a much superior block, but which will be quicker and easier to operate.

With these objects in view, the invention contemplates the forming of the designs on the print blocks by burning away portions thereof. In the preferred form of the invention, this burning is accomplished by means of an intense ccncentrated or focused narrow flame, for example, such as is produced by a small blow torch. The effect of such intense and localized heating is to burn away the narrow portion of the wood, upon which it' is concentrated, so rapidly that there is not sufficient time for the heat to be transferred for any substantial distance through the wood so as to injure or seriously deteriorate the adjacent parts. In this way, a groove may be quickly out to follow any straight or irregular line in anydirection across or along the lines or pins of the block, and although the sides of the groove will, of course, be charred by the heat, the charring does not extend for: any substantial distance beyond the sides of the groove so that the adjacent portions of the pin or line, even though very narrow, will re'tain its strength sufficiently for all purposes of printing. Furthermore, the groove which results from burning with a concentrated flame in this manner will be formed with a rounded bottom, so that where very narrow remnants of the pin or line are left beside such groove, they will, nevertheless, be much stronger than would be formed by cutting a similar block with a chisel, because of the fact that the narrow top will be supported upon a base which broadens as it extends under the rounded bottom of the grooves.

Furthermore, since the groove is formed continuously by a steady and continuous movement of the flame over the block, the result is certain to be a continuous groove with the portion in each line or pin accurately aligned with the portion in the adjacent lines or pins, and in this way, varied and irregular grooves are formed with the utmost simplicity, whereas to obtain similar efiects by hand would involve a long and tedious process, requiring the utmost care.

In the accompanying drawing, we have illustrated one method of applying our invention:

In Fig. 1, we have shown in perspective a print block such as is commonly used, upon which a design has been cut, and upon which a groove is being formed in accordance with the present invention;

In Fig. 2 is shown a fragmentary view in perspective, upon a large scale, of a. portion of a line block having grooves formed therein by burning in accordance with the present invention.

In the block 10, as shown in Fig. l, the surface along the resulting line.

has first been grooved by forming shallow sawcuts 11 along closely spaced parallel lines. The design is then drawn upon the block and the broad outlines of the design are formed by cutting away with a chisel the larger spaces indicated at 12. The narrow grooves 13, which in this case are used to simulate marble veining, are formed by burning in accordance with the present invention, and to this end a blow-torch, which in the present case is indicated as a simple alcohol torch 14, is shown with its needle flame playing on the block, so that it is cutting one of the grooves 13.

In Fig. 2, the groove which results from the burning is shown on an enlarged scale. As illustrated at 15, the bottoms of the grooves are rounded, and when close together will thus leave a narrow peaked, but broad based, pin or remnant 16.

When a block such for example as that shown in Fig. 1, is used in printing, narrow transverse grooves will be left in the paint coating corresponding to the grooves 13, and ifa different color is to be applied in these grooves, a complementary block must be formed having lines following the same paths as the grooves. In some cases, the narrow lines of these complementary blocks may be formed by burning grooves on either side of the line, and then cutting away, wherever necessary, with a chisel beyond the grooves. Ordinarily, however, it will be most satisfactory and economical to form cast metal lines which may be secured to blocks in the usual manner used to print the narrow lines corresponding to the grooves.

These metal lines are commonly formed by burning into solid wooden blocks grooves as nearly as possible along the same paths as the grooves burned in the line blocks. In this case,

'it is preferable, where possible, to burn the grooves by means of heated blades, since the depth of the groove in this way can be more readily controlled, and the metal, when cast, may therefore be of substantially uniform depth Where extremely irregular lines are to be formed, however, the direct flame-burning method, as described above,

may be used for forming the matrix in which the typemetal is cast. In this case, the flame should be adjusted as narrow as possible, and the burning should preferably be somewhat deeper than in burning grooves on the line blocks. Where extremely irregular lines are to be used, so that it may be difficult to reproduce a line exactly, the groove may be burned into the solid block as already described, and the metal cast into this block as a matrix. The metal in this case should, of course, be one which melts at a relatively low temperature, so that the block is not injured by the heat of the metal. If the surface should be charred to any substantial extent, the charred portion should be planed OE, and thereafter saw cuts may be formed, and the remainder of the design cut out in the usual way.

In the above, we have given a preferred embodiment of our invention and various modifications thereof, in order to illustrate its principle and application. It is to be understood, however, that these are intended to be exemplary only, and that many other changes and modifications may be made without departing from the scope of this invention.

We claim:

1. The method of forming a print block for a pattern having relatively narrow lines thereon which comprises cutting the broader outlines of the pattern from the wood block and forming said narrow lines by burning the wood therealong by means of a narrow focused intense flame.

2. The method of forming a printing block for a pattern having relatively narrow lines thereon which comprises cutting the broader outlines of the pattern from the wood block and forming a narrow transverse portion of a line or a pin by cutting at least one side thereof with a flame whereby said narrow portion may be freed from an adjacent portion without subjecting it to any strain and whereby said remaining portion will be formed narrow at the top with a broadened base.

JOHN ELMER. BERNARD J. KELLY.

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