US3054347A - Matrix packing - Google Patents

Description

J. F. SANTO MATRIX PACKING Sept. 18, 1962 Filed June 13, 1958 R. DE m CLC N 5R E ww v 2, m N

R ww 3,054,347 MA PACKING John F. Santo, 1336 Live Oak Drive, Jacksonville, Fla. Filed :lune 13, 1958, Ser. No. 741,933 3 Claims. (Cl. lill-401.2)

This invention relates to a method of packing a printers matrix and to a printers matrix packing material, and to a novel machine for the application of the packing material to the matrix.

In the printing of newspapers and similar linotype printing processes, it has long been the practice to collect type in a suitable chase as a form, to press a moist fibrous material matrix sheet against the type by exerting pressure against the back surface of the sheet, by means of compressed air or a rubber pad, thereby to impress the type into the front face and to cause projections to be formed in the back face roughly corresponding to the type impressions, the projections being separated on the back face by valleys or depressed areas between the projections, and, usually following partial drying of the molded matrix sheet, to paste strips or rectangular pieces of thick paper or cardboard in the Valleys of the back face. Following such backing of the valleys, the sheet is normally subjected to hot vacuum drying and shrinking and, when completely dry, molten metal is cast by pressure against the front face of the matrix to form a printing segment or plate.

Various arrangements have been suggested to do away with the manual pasted strip packing steps, including the provision of extra sheets of thick material on the back of the matrix sheet which are ground away or otherwise thinned to form a matrix sheet having a smooth back face. Mats have also been provided with a sheet of material on the back face which is soft at the time of making the impression but which may thereafter be hardened to` provide a hard coating on the back of the matrix sheet sufcient to support the portions of the sheet between the impressions. It has also been suggested to make the matrix itself of a material which may be hardened after the impression has been made. Such earlier suggestions have provided a matrix sheet thicker than those for which the casting machines were designed, and the adoption thereof requires rebuilding or replacement of the casting machine and, usually, of the presses, or changes in all of the Linotype machines and the type produced thereby, because of the excess thickness of the final matrix sheet, or these systems have required so much additional processing as to be uneconomic.

It is an object of this invention to provide a method of packing matrix sheets formed in the usual manner from the usual materials, and to provide a matrix packing material useful in such process, such that the final matrix is of the same thickness as a hand-packed, glued-backing strip type matrix, whereby the final packed matrix is usable in connection with existing equipment.

It is a further object of the invention to provide a method and a packing material for packing matrix sheets in a manner such that the nal drying of the matrix sheet, after packing, which shrinks the matrix sheet by approximately one-twentieth of its original width and length, does not adversely affect the packing, but provides a matrix shrunk to the desired degree with the' packing still properly adhered and properly effective to support the non-impressed, portions during subsequent casting of the printing segment.

The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as Yto its organization and method of operation, together with further objects and advantages thereof, may best be 3,054,347 Patented Sept. 18, 1962 understood by reference tothe following description taken in connection with the accompanying drawings, in which:

FIG. l is a plan view of a portion of the back face of an impressed or molded matrix sheet;

FIG. 2 is a similar view of the portion of the back face following the application thereto of packing material in accord with the invention; and

FG. 3 is a partially broken away and partially schematic view illustrating generally apparatus useful in the process of this invention and showing steps of the process.

FIG. 1 shows the back face 5 of a matrix sheet 6 following the impressing or molding thereof, with raised projections 7, `8 which correspond, roughly, to the depressed type and pictorial impressions which have been formed in the hidden front face.

As shown in FIG. 2, according to the invention, matrix packing material 9 has been applied to the depressed valleys lil, 11 which exist on the back face between the several projections '7, `8. The surface 14 of the packing material is substantially iiush with the projections, and it is important that the thickness of the matrix is not changed by the application of the packing material.

The process for packing the matrix is performed in a manner which may be understood with reference to FIG. 3. The matrix sheet 6 into which have been pressed the type depressions 16, 17 is laid with its front face 18 in contact with a surface plate 20. Heat, such as by means of electric light bulbs 21 in a reflective hood spaced a few inches above the sheet is applied for a suflicient length of time to warm the back face 5 to a temperature of at least about degrees F. but not higher than about 200 degrees F. It has been found that about 30 seconds of exposure of a matrix sheet about 18 by 23 inches in size under a reiiector having six 500 Watt bulbs provides appropriate heating of the matrix. Such heating performs two functions; it provides a preliminary or partial shrinkage in size of the matrix, and it provides a warm and partially or nearly dry surface to which the packing material readily adheres and on which it tends rapidly to set or cure. It is not essential to the process, however, that the matrix surface be hot at the time the packing material is applied, although the desired results are more dit`n`cult to attain if the matrix back face 5 is not almost dry or only very slightly damp.

When the matrix surface 5 has been dried and preferably heated approximately, a tubular nozzle element 22 is brought into contact across the sheet and slowly moved from one end of the sheet to the other so as to traverse the area to be packed.

The nozzle element 22 is generally cylindrical, but the lower portion thereof which comes in contact with the projections 7, `8 of the matrix is slightly flattened as shown at 23. Approximately centrally of this flattened portion 23 are a series of openings, such as opening 24, and satisfactory results may be obtained if these openings are each approximately one-sixteenth of an inch in diameter and spaced three-sixteenth of an inch on centers along the length of the flattened portion 23. The hollow interior 27 of the nozzle element is supplied with the semiliquid packing material as indicated at 25, through a connecting tube 26 extending to the nozzle from a pressurized reservoir or container 28. The packing material is forced from the container into tube 26 by applying compressed air from a suitable source 29 into end 3@ of the container behind a free piston 31 tted into the container and preventing the air in end 30 from contacting the semi-liquid packing material. The air pressure in the container-is adjusted and controlled by a valve 32, and a pressure gauge 33 is preferably provided to assist the operator in maintaining appropriate pressure. The pressure is adjusted to be a few or many pounds per square inch suiicient to cause the material to be ejected at the desired rate from the nozzle opening 24. 'Ihe viscosity of the material, the size and length of tube 26, the size of openings 24, and other factors, some of which may be subjected to periodic variation, determine the precise pressure that is required to force the material from the openings.

During movement of the nozzle along the back face of the matrix, packing material issues from each of openings 24 whenever the individual opening is opposite a valley, such as valley 1l. Each hole is closed, however, when it encounters one or another of the projections, such as projection 7. As seen in FIG. 3, opening 24 has supplied no packing material on projection 7 by which it has been closed, but the opening supplies material into valley 10 as it leaves projection 7, as indicated, substantially filling the valley before opening 24 reaches and is closed by the next projection 34.

The matrix, which has been impressed with the type in the chase while in a wet condition, and having been partially dried and shrunk thereafter, and, while still slightly moist, having been placed on the surface plate and subjected to heating to raise the temperature of the back face to about 150 degrees F., will have become warped or wavy. A smoothing roller 35 is carried by an arm 36 fixed to the nozzle to roll freely along the sheet immediately in advance of the nozzle, thereby to insure that the front face 18 is in contact with the surface plate for portions of the sheet at and near the nozzle as it progresses along the sheet.

After the nozzle has completed the traverse, the matrix with the valleys of its back face now filled or packed With the material is permitted to remain under the heating elements 21 for about ten to thirty seconds. The speed of movement of the nozzle along the matrix may be about one inch per second. 'l'he heating bulbs 2l preferably remain energized throughout the operation. Setting or curing `of the packing material is hastened by the use of heat after the material has been applied, and such curing, particularly of the exposed surface of the packing is important because the packed matrix is now placed in the usual shrinking and drying machine in which shrinkage of about 4 to 5 percent in plan dimensions is completed under hot vacuum conditions. In the usual type of shrinking and drying machine, the packed matrix is held in place against a curved plate by means of vacuum applied through perforations in the plate. If the packing material were not cured on the exposed surface, it would be sucked in and would gum the vacuum perforations of the machine.

It is necessary that the material applied to pack the matrix not be destroyed or made brittle from the elevated temperatures encountered in the shrinking and drying machine or from the temperatures of 400 to 500 degrees F. involved in the casting box in which the printing plate is cast against the matrix. The material must also be capable of strong adherence to the matrix. A material meeting these and other requirements is prepared by mixing the following ingredients in percentages by weight:

To this mixture is then added an equal Weight of starch, which may be conveniently in the form of wheat flour or corn starch, with sufficient agitation or mixing to form a thick, smooth, gummy, semi-liquid, which has Very little or no tendency to pour but which may be forced through tubes and openings. The constituency of the material may vary from that given above by adding starch in a ratio to the latex mixture of between approximately 40-60 and 60-40. If less than about 40 parts of starch is added to 60 parts of the latex mixture, the material flows readily but sets or cures less rapidly, whereas, starch added above the ratio of 60-40 so thickens the material that it becomes very dificult to force through tubes or small openings and, thus, difficult to apply.

The ferrie oxide is included primarily for its coloring effect, and may be omitted without adversely affecting the material or it may be replaced by some other coloring material. Colored material is more convenient to use since contrast with the matrix color aids in detection of any errors in application on the matrix.

The latex rubber constituent of the latex mixture comprises substantially 40 parts of solids to 30 parts of water. Thus the latex mixture comprises in total about 41 percent of water. The clay filler provides thickening and may be replaced by slightly increased starch in preparing the final material. I'he zinc oxide hastens curing and is desirable to reduce the time of heating under lamps 21 prior to introduction of the packed matrix into the shrinking and drying machine. Alteration of the amount of zinc oxide is permitted, but omission unduly prolongs the curing time, and increasing the amount may result in too rapid curing and clogging of the openings 24 of the spreading nozzle.

The casein component may be reduced or increased by about one-half but adherence of the material to the matrix is adversely affected or spreading is made difficult if less than about 2 or 3 percent or more than about 7 percent of casein is included.

The percentage of water is not critical, but sufficient Water should be included t0 insure that the latex mixture exists as an emulsion, yet excess water is to be avoided as adding to the drying time. The ammonium compounds are emulsifying agents and may be replaced if desired by other known emulsifying agents.

The process as described provides packing of all valleys having dimensions of about three-sixteenths of an inch and greater. lt is not necessary that very small valleys be packed since the pressure of the molten metal in the casting box, and the holding suction against the back of the matrix, are not sucient to collapse the matrix except in areas where the type or pictorial impressions are widely spaced, leaving large white areas therebetween. All such areas as might be collapsed are packed in accord with the process herein described, whereby the final plate does not comprise areas raised high enough to print at any portion not originally impressed into the matrix.

It will be seen that in the present process, one man may take the matrix sheets from the moulding machine, complete the packing and place the packed matrix sheets in the shrinking and drying machine in a matter of about a minute and a half or approximately as fast as the sheets can be moulded. The process now normally employed in newspaper plants requires several minutes of time by one or two skilled packers using bits of cardboard which are glued in place, plus additional personnel to deliver the moulded matrix sheets to the packing stations, to collect the packed sheets for drying and to perform other related steps and functions eliminated by the process herein described.

While only a certain preferred embodiment of this invention has been shown and described by Way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended in the appended claims to cover al1 such modifications as fall within the true spirit and scope of this invention.

What is claimed as new and what it is desired to secure by Letters Patent of the United States is:

l. The method of packing a moulded matrix sheet which comprises applying into the valleys of the back face of the matrix sheet prior to completion of the drying and shrinking thereof a heat-curable, adherent semiliquid packing material up to the level of the tops of the projections on said back face, and heating said sheet and said thereto applied material in the absence of the moulding form against which said sheet was moulded to a temperature and for a length of time suicient to cure said material and to complete the shrinking and drying of the sheet.

2. The method of packing a printers matrix sheet which has been moulded while wet against a form to leave an impressed front face and an irregular back face having projections corresponding roughly to the front face impressions and having valleys between said projections, said method comprising the steps of heating at least said back face of said sheet to between about 125 and 200 F., placing said sheet front -face down on a at support, applying into said valleys a heat-curable, adherent semi-liquid packing material substantially to ll said valleys up to approximately the level of said projections, and thereafter heating said sheet in the absence of said form as packed with said material to shrink and complete the drying of the sheet and to complete the curing of said material.

3. The method of packing a moulded matrix sheet which comprises applying, prior to nal hot shrinking of the sheet, into the valleys of the back face of the sheet, a thick, heat-curable latex emulsion packing material up to the level of the projections on said back face and, thereafter, heating said sheet and material to complete the shrinking of the sheet and to cure the material in the absence of the moulding form against which said sheet was moulded.

References Cited in the le of this patent UNITED STATES PATENTS 134,196 Crump Dec. 24, 1872 286,821 Hoe Oct. 16, 1883 1,988,094 Stimpson Jan. 15, 1935 2,007,566 Ernewein July 9, 1935 2,133,981 Frazier Oct. 25, 1938 2,337,550 Crosby Dec. 28, 1943 2,405,724 Wilder Aug. 13, 1946 2,492,348 Baker Dec. 27, 1949 2,541,297 Sampson et al. Feb. 13, 1951 2,650,206 Stock Aug. 25, 1953 2,697,253 Kurft Dec. 21, 1954 2,702,927 Travis Mar. 1, 1955 2,718,664 Schweitzer Sept. 27, 1955

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