JPS6334937Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an ink roller assembly for supplying ink to a printing device.

TECHNICAL BACKGROUND With recent developments in printing technology, hollow ink rollers filled with ink are replacing ink supply rollers that are partially immersed in ink. Such hollow ink supply rollers generally have a number of holes in their cylindrical wall and a peripheral surface of the roller for smooth ink transfer to the ink transfer roller or to the printing type. It has an ink permeable coating.

However, such an ink supply roller has the following drawbacks.

In other words, if the roller is not used for a long time,
The coating becomes partially saturated with ink,
If such a roller is used again, the printing may become darker in some areas or the ink may leak to the outside.

Furthermore, as the ink supply roller is used for a long time, the sharpness of the print gradually decreases, making it difficult to read the printed characters. In such a case, if the person reading the text is a human, the printed characters will become unclear, but mechanical reading means such as an optical character reading machine cannot perform such sensing. This is difficult and there is a risk of serious misreading.

In order to solve the problems of ink leakage and blurring of printed characters, solid sintered plastic rolls, sponge-like open-cell rubber rollers, and the like have been proposed as conventional techniques. However, even with a roller having such a configuration, it has not been possible to effectively prevent the above-mentioned deterioration in print clarity. Such prior art includes U.S. Pat. No. 3,002,449;
No. 3044397, No. 3158095, No. 3238870, No.
No. 3253542, No. 3336244, No. 3408984, No.
No. 3491685, No. 3738269, No. 3812782 and No.
It is disclosed in No. 3945723.

Purpose of the invention The object of the invention is to provide an ink roller that solves the problems of the prior art as described above.

Structure of the invention That is, the ink roller according to the invention includes a hollow cylindrical body made of a microporous material having micropores with a diameter of 2 microns to 70 microns, and a closed chamber formed inside the cylindrical body. means for closing the ends of said cylinder; an ink having a predetermined viscosity contained in the closed chamber; and an elastic body mounted around said cylinder for transferring the ink from the surface of the cylinder to the printing device. The microporous sleeve is characterized by having an axial length shorter than the axial length of the cylindrical body so as to expose a portion of the cylindrical body directly to the atmosphere.

Effects of the Invention The ink roller according to the present invention has the above-mentioned configuration, and ink is sucked through the cylindrical wall to the outer circumferential surface of the cylindrical body by capillary action caused by the micropores in the cylindrical body wall. In this state, the pores of the cylinder are saturated, but the surface is hardly moist. During printing, the microporous sleeve is pressed against a transfer roller or printing type to supply ink to them, and as a result, the sleeve is repeatedly compressed and decompressed, and when decompressed, it is removed from the printing roller. Suction ink.

As the ink inside the print roller is discharged,
The internal pressure decreases, but when it exceeds a certain level, the atmosphere pushes away the ink in the pores of the part of the printing roller exposed to the atmosphere and enters the printing roller.

Effects of the Invention As mentioned above, the ink roller according to the present invention is a roller that stores ink within the roller, and by making the microholes provided in the cylindrical body have the diameter as described above. The capillary action of the roller allows the ink inside the sleeve to be sucked to the outside in an appropriate amount while preventing excessive suction. If you reuse the
It is possible to avoid printing from becoming partially dark. Further, due to the above-mentioned effect of the pores of the cylindrical body, leakage of ink can be avoided even if the cylinder is not used for a long period of time.

Furthermore, as mentioned above, the fine pores of the printing roller are designed so that the internal ink is absorbed into the fine pores by their capillary action, but they are made so fine that the ink does not leak to the outside. There is. However, as mentioned above, a part of the printing roller is exposed to the atmosphere, so when the ink is discharged from inside the printing roller and the internal pressure decreases, the air can enter the inside of the printing roller through the exposed part. Therefore, pressure equilibrium can be achieved before the pressure drop inside the printing roller becomes too large, and therefore, ink can be smoothly supplied from the inside of the printing roller to the outside by capillary action.

As can be seen from the above, the present invention can solve the problems of the prior art described above.

Example Embodiments of the present invention will be described in detail below based on the figures.

As shown in FIG. 1, an ink roller 11, which is an example of the present invention, is used to directly supply ink to printing type. Ink roller 11
includes a cylindrical body 12 made of a microporous material, such as sintered ultra-high molecular weight polyethylene. Of course, the cylindrical body may be formed of a microporous material other than the above, such as metal. The wall thickness of the cylinder when made from polyethylene material is approximately 0.065 inches or approximately 1.65 mm, and the diameter of the pores is uniform and 2 to 2 mm.
It has a value of 70 microns. If the cylinder is made of metal, its wall thickness is approximately 0.010 inch or approximately 0.25 mm.
The diameter of the micropores is approximately 10 microns. For more flexible materials, the cylinder wall thickness may be greater than 0.070 inches or 1.78 mm, and the pore diameter may be greater than 40 microns. The ends of the cylinder 12 are sealed by means such as end caps 13 to provide a substantially cylindrical chamber within the cylinder. Each end cap 13 includes an axially located, outwardly extending shaft 14 that engages a roller support arm 16 normally provided on the printing device.

Inside the cylinder there is a printing ink reservoir,
The ink has a temperature of about 1000 centipoise or 100 to 100 centipoise depending on the nature of the microporous material at a temperature of 70 °C or 21.1 °C.
It has a viscosity of 5000 centipoise. Surrounding the cylinder 12 is a sleeve 18 made of a microporous material such as an elastomer or rubber. This material has a hardness of 5 to 45 durometers on the Shore D scale. In a preferred embodiment, the wall thickness of the sleeve is approximately 0.040 inches or approximately 1.03 mm;
The diameter of the pores is selected so that the ink can pass through them. The sleeve covers substantially the entire outer surface of the cylinder in the axial direction (with the exception of both end portions 15 of the cylinder directly exposed to the atmosphere) and is adapted to come into direct contact with the printing type.

As shown in FIGS. 2 and 3, the printing head 2
3 translates tangentially with respect to the roller 11, the printing type 21 is moved against the sleeve 18 of the roller 11.
, and ink is supplied to the printing type. The tangential speed of the translation of the printing head imparts a rotational movement to the rollers and compresses the sleeve portion 22 in contact with the type 21.

As the compressed sleeve portion 22 expands back to its original position due to its elasticity, suction by the sleeve is created, drawing ink from the roller wall or cylinder 12 into the sleeve. On the other hand, ink is stored in the main body of the cylinder 12 from the ink reservoir inside the cylinder due to capillary action due to the micropores in the cylinder 12 . After a number of printing cycles, the suction of ink from within the roller causes a pressure drop within the roller. When this pressure drop is large enough to overcome the resistance of the ink within the walls of the sintered cylinder, air is drawn into the interior of the roller through the pores of the sintered cylinder and pressure equilibrium is re-established.

Furthermore, as a result of the experiment, it was found that the roller 11 maintains a constant printing strength (sharpness) over almost its entire service life, and that the printing strength does not drop significantly even at the end of its service life. . For example, the roller according to the present invention prints effectively at a constant printing strength up to 140,000 printing cycles, and after that, the printed characters suddenly become difficult to read after 5,000 printing cycles. I understand. This sudden drop in printing strength makes it easy to determine when it is necessary to replace the roller.

Another advantage of the unique configuration of the roller 11 of the present invention is that the pores within the sleeve and cylinder are saturated with ink and are always ready for printing. It also has the advantage of not requiring any transport rollers to supply ink to the printing type. Therefore, roller 11
By using this method, it is not necessary to take the waiting time required to maintain the printing intensity of the printing device at a constant state. Even after a long period of inactivity, the roller 11 of the present invention
It is possible to perform printing with a desired printing strength without causing ink blur or excessive ink adhesion.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the ink roller of the present invention that uses a porous sleeve, and
5 through 5 are each a cross-sectional view of the embodiment shown in FIG. 1, and are successive views illustrating its function during an ink supply cycle. 11: Ink roller, 12, 32: Cylindrical body, 1
3, 33: End cap, 18: Sleeve, 2
1: Printing character, 31: Ink roller assembly, 3
8: Transfer roller, 39: Ink.

Claims (1)

[Scope of utility model registration request] a hollow cylinder made of a microporous material having pores between 2 microns and 70 microns in diameter; means for closing the ends of the cylinder to form a closed chamber within the cylinder; A portion of the cylinder is separated by an ink having a predetermined viscosity present in the chamber and an elastic microporous sleeve fitted around the cylinder to transfer the ink from the surface of the cylinder to the printing device. An ink roller assembly characterized in that the ink roller assembly has an axial length shorter than the axial length of the cylindrical body so as to be directly exposed to the atmosphere.