US2578921A - Inking apparatus for use with inks having highly volatile solvents - Google Patents

Description

Dec. 18, 1951 2,578,921

G; CRAMER INKING APPARATUS FOR USE WITH INKS HAVING HIGHLY VOLATILE SOLVENTS Filed 001;. 29, 1949 INVEINTOR. BY 5 ,4 TTOIFNEYS Patented Dec. 18, 1951 UNITED STATES PATENT OFFICE INKING APPARATUS FOR USE WITH INKS HAVING HIGHLY VOLATILE SOLVENTS George Cramer, Peekskill, N. Y., assignor to Sinclair and Valentine 00., New York, N. Y., a corporation of New York Application October '29, 1949, Serial No. 124,354

2 Claims. l

The present invention relates to a novel, and improved apparatus for printing with inks having highly volatile solvents which tend to dry rapidly on the press.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements,combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a schematic view of an illustrative form of printing mechanism for carrying out my present process; and

Figure 2 is a developed enlarged view showing a portion of the surface of one of the cylinders shown in Figure 1.

The present invention has for its object the provision of a novel and improved process of printing with highly volatile or rapid-drying ink A further object is the provision of a process by which the ink on the inking mechanism may he maintained in optimum printing condition, even under adverse operating conditions.

In the use of rapid-drying printing inks on high speed rotary printing presses, the room temperature and the temperature increase due to the running of the inking mechanism often cause the ink solvent to evaporate much too rapidly so that the ink is too viscous as it is applied to the printing surface. To overcome this, additional solvent may be added to the ink, but this requires thorough mixing of the ink and often results in improper feed of the ink. Alternatively, a higher boiling point solvent may be used, but this slows down the drying of the ink and thereby reduces the productivity of the printing press.

In the use of water-base printing inks, glycerine is sometimes added to reduce the rate of evaporation, or in the use of petroleum solvent, rapid-drying inks, a higher boiling fraction may be used as the solvent, so as to reduce evaporation on the press. However, these expedie'nts are highly disadvantageous as pointed out above.

According to the present invention, an ink having a highly volatile solvent is fed in the usual manner to the inking mechanism and printing surface, and even those solvents which are more rapid in evaporation than conventional solvents may be used. The ink is fed from the ink fountain to a distributing drum and from that to the other rollers and drums of a conventional inking mechanism, after which it is taken and applied by the form rollers to the letterpress plates on the plate cylinder. As the ink is fed, the thickness of the ink film is greatly reduced and while it maybe of theorder of one-thousandth of an inch at the ductor roll, it is usually only a few hundred-thousandths of an inch thick at form rollers, resulting in a great increase in the surface area of the ink and correspondingly greater evaporation. Intermediate the fountain and form roller is a solvent ,fountain which is provided with a fountain roller, doctor blade and feed rollers by which solvent may be fed to the inking mechanism at the desired, regulable rate so as to compensate for any original lack of solvent in the ink or for any solvent lost by evaporation from the relatively large surface area of the inking rollers.

The fountain roller for the solvent feed is pref erably a cylindrical roller having a uniformly grained or cellular surface by which a regulable amount of solvent is fed as it rotates in the solvent fountain.

As the solvent is fed to the ink distributing system, the solvent is distributed and Worked into the ink to a certain extent, but in the early stages the solvent is concentrated at the outer layer of the ink film, so that it is the added solvent rather than the solvent originally contained in the ink which is first subject to evaporation, thereby maintaining the ink iii-excellent printing condition as it is fed and applied to the printing surface.

Preferably, the solvent is fed upwardly from the fountain to the inking mechanism and is applied to one of the ink drums at a point where the drum has given up a normal quantity of ink to an inking roller which is to feed the ink to the printing surface.

In theuse of water base inks, in which the ink comprises essentially a thixiotropic suspension of carbon black in water, the added solvent is water and the rate of feed is such as to maintain a normal amount of water in the ink as the ink is applied to the printing surface. The rate of feed of the ink is regulated in the usual manner in accordance with the speed of the press and the type of subject being printed, and the rate of water fed from the solvent fountain is determined in accordance with air temperature of the inking system and the humidity and rate of air flow over the rollers, enough water being fed so that when the ink is applied to the letterpress plate it is of proper printing consistency.

Where rapid-drying oil inks are employed, the solvent fed will be determined by the composition of the ink. Usually, such inks comprise a pigment, toner, varnish, or binder and a solvent for the binder and varnish. In most such inks, the solvent is a narrow boiling petroleum fraction, boiling from 280 C. to 300 C. or thereabouts, and in such a case the separate solvent fed would be such a petroleum solvent. Alternatively, a more volatile solvent could be used both in the ink and in the special solvent feed so that the ink would dry even more rapidly than normal after it had been applied to the paper.

Where special lacquer inks are employed, comprising a pigment or dye, a nitrocellulose ester asthe binder, a plasticizer and a highly volatile solvent such as butyl or amyl acetate, the solvent fed from the solvent fountain may be amyl or butyl acetate or other suitable compatible and highly evaporative solvent.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof.

The drawings illustrate a typical embodiment of an inking mechanism in accordance with the present invention and particularly adapted for carrying out the novel process of the invention. In this mechanism the printing surfaces to be inked are supported upon a plate cylinder In which cooperates with an impression cylinder I l and the paper to be printed is passed between them and receives ink from the surface of the 4 32 is positioned below and in contact with the ink drum 22 and between the last of the transfer rollers 28 and the first of the transfer rollers 24. Means are provided for feedin ink solvent from a solvent fountain to an intermediate portion of the series of inking drums and preferably to the central rotary inking member, in this case ink drum 22. As embodied, a solvent trough 40 is provided which is partially filled with water,

letterpress printing plates conventionally mounted I on the plate cylinder Ill. The inking mechanism comprises an ink trough 12 in which is slowly rotated a fountain roller I4, the thickness of the ink film fed from the fountain roller I4 being regulated by means of an adjustable blade IS in the manner of a conventional overshot ink fountain. Ink is transferred from the fountain roller l4 to a distributing drum l8 by means of a periodically oscillating ductor roller 20 so that relatively thick patches or stripes of ink are fed from the fountain roller I4 to the surface of the distributing drum I 8. A second distributing drum 22 is provided and receives ink from the first distributing drum I8 by means of the transfer rollers 24, while ink is fed from the distributing drum 22 to the form rollers 26 by means of the transfer rollers 28 and the form distributing drums 30. All of the rollers and drums I8, 22, 24, 26, 28 and 30 are driven in contact with each other and some or all of these rollers and drums may be vibrated to improve the distribution and thorough mixing of the ink. The fountain roller l4 operates at a very slow' speed and while the form rollers 26 are adapted to rotate at the same surface speed as the cylinder I0 and drums I8, 22 and 30 are preferably driven at progressively increasing speeds so that the relatively thick film of ink transferred by the ductor roller 20 is progressively thinned out as it is fed forward toward the printing surface.

A transfer and distributing roller 32 is also provided and rolls in contact with one of the inking rollers or drums and is preferably located to contact with a central inking roller or drum at a point where the drum has delivered most'of the ink carried by it. In the form shown the roller all petroleum distillate or other appropriate solvent, and has mounted in it a rotatable fountain roller 42 which is continually rotated at a slow speed during the operation of the press. The ductor blade 44 regulates the amount of solvent retained on the surface of the roller 42 and available for feeding to the inking mechanism while the feed of solvent from the roller 42 to the transfer and distributing roller 32 may be further regulated by variation of the rapidity of oscillation and dwell of the ductor roller 46, the roller 46 periodically contacting first with the solvent fountain roller 42 and then with the transfer and distributing roll 32 so as to feed solvent from the solvent fountain to an intermediate member of the series of inking rollers and drums.

As the inking rollers and drums rotate during the operation of the press, ink and solvent are continuously fed to the inking mechanism and the solvent loss by evaporation from the relatively large surface of the inking mechanism is continuously replenished by the added solvent fed from the solvent fountain, while the solvent and ink are continuously mixed due to the working of the ink and solvent by the various rollers and drums at their points of contact as well as by the difference in speeds between the various rollers and drums.

Figure 2 is a detailed fragmentary and enlarged View showing a preferred form of surface of the cylindrical roller 42 and as shown in Figure 2 the surface of the roller is provided with minute cellular cavities which are preferably, of regular shape (usually square), and may be of the order of ten thousandths of an inch each per side and of a depth of the order of one thousandth of an inch, although these dimensions and the specific shape of the cellular cavities is purely illustrative.

The form of the inking mechanism shown insures a continuous, uniform and regulable re- I plenishment of the solvent so that the rate of feed of the solvent may be accurately controlled as required by the operating conditions of the press, particularly the temperature of the various rollers and drums of the inking mechanism inasmuch as continued operation of the press causes considerable heat to be generated in the rollers and drums some or all of which are made of resilient material such as rubber.

The'invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. An inking mechanism for high speed rotary printing presses including in combination an ink fountain, a plurality of ink transferring and distributing rollers contacting with each other to feed ink as they rotate and to apply a film of ink to a rotary printing surface, a solvent fountain, and means for, feeding solvent at a regulable rate from said fountain to an intermediate one 5 6 of said rollers to compensate for loss of ink solvent by evaporation said solvent feeding means REFERENCES CITED comprising transfer rollers between the solvent The following references are of record In the fountain and one of the inking rollers, said solfile of thls patent:

vent transfer rollers applying the solvent to one of the inking rollers after the inking roller has UNITED STATES PATENTS Number Name Date transferred ts film 0f mii- 337,702 canfield Dec. 22, 1931 2. An inking mechanism according to claim 1 2 084 418 Walter June 22 1937 in which the solvent fountain includ s a minutely 2234727 Frazier Mar 11 1941 cavitated rotatable cylinder r nn in a trough 10 7 Dietrich H May 6 1941 which may be filled with Solvent 2:347:619 Taylor et al Apr. 25, 1944 GEORGE CRAMER.

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