JP2001212938A - Ink supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink supplying device capable of forming an ink film having a uniform film thickness on an outer periphery of a form roller. SOLUTION: The form roller 4 is oppositely provided on an ink fountain 1 to form an ink reservoir 5. A doctor blade 6 is advancingly or retractably provided on the outer periphery of the roller 4. A shielding plate 9 is provided in the reservoir 5, and an ink outlet 10 is formed between a lower end of the plate 9 and a bottom plate 2 of the fountain 1, thereby reducing a contact area of the ink with the roller 4. Thus, even when a pressure is generated at the contact of the roller 4 with the blade 6 by moving the ink downward by the contact with the roller 4, its pressure is low, and an ink passing amount at the contact of the roller 4 with the blade 6 is made uniform by the reduction in the pressure. Thus, the ink film of a uniform thickness is formed on the outer periphery of the roller 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink supply device for supplying ink onto a printing plate wound around an outer periphery of a plate cylinder.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional ink supply device. In this ink supply device, an ink application roller 4 is disposed opposite to an ink fountain 1 having a bottom plate 2 having an inclined upper surface and a pair of side plates 3, and an ink reservoir 5 is formed between the ink fountain 1 and the ink fountain 1. The ink filled in the reservoir 5 is adhered to the outer periphery of the inking roller 4 rotating in the direction of the arrow, and the adhered ink is scraped off by a doctor blade 6 provided to be able to advance and retreat with respect to the outer periphery of the inking roller 4. After the ink film thickness is adjusted, the ink film is transferred to a printing plate on a plate cylinder 7 opposed to the ink forming roller 4.

[0003]

In the above-mentioned ink supply device, since the ink contact area with the outer periphery of the ink forming roller 4 is large, the ink contacting the ink forming roller 4 is turned downward by the rotation of the ink forming roller 4. Moving. Due to the downward flow of the ink, pressure acts on the contact portion between the inking roller 4 and the doctor blade 6, and the pressure increases as the viscosity of the ink increases, and the ink pressure causes the contact between the inking roller 4 and the doctor blade 6. The amount of ink passing between the portions becomes non-uniform over the entire length between the contact portions, and there is a problem in that density unevenness occurs in a printed matter.

That is, the contact pressure between the ink forming roller 4 and the doctor blade 6 cannot be made uniform over the entire length of the ink forming roller 4 in the axial direction due to the processing accuracy of both parts. When the ink in the ink reservoir 5 flows downward due to the rotation of the pressure roller 4 and a pressure is generated, the contact portion between the ink forming roller 4 and the doctor blade 6 has a small amount of ink passing through the portion where the contact pressure is strong and the contact pressure is weak. In some parts, the amount of ink passing increases,
An ink film having a uniform thickness cannot be formed on the outer periphery of the ink forming roller 4.

Further, when the hardness of the outer periphery of the ink forming roller is increased, when the ink forming roller and the doctor blade come into contact with each other, the amount of deformation of the outer periphery of the ink forming roller is reduced, so that the ink forming roller has a lower ink hardness than an ink forming roller having a lower hardness. The thickness of the ink formed on the outer periphery of the setting roller 4 can be made uniform. However, when paper dust is mixed into the ink, the paper dust is generated between the ink setting roller 4 and the doctor blade 6. Jamming occurs, and the ink adhered on the ink setting roller 4 is scraped off at the position where the paper dust is jammed to form streaks, thereby causing a problem that streaks also occur in printed matter.

It is an object of the present invention to provide an ink supply device capable of forming an ink film having a uniform thickness on the outer periphery of an ink forming roller.

[0007]

According to the present invention, there is provided an ink fountain having a bottom plate and a pair of side plates, and an ink forming roller for forming an ink reservoir between the ink fountain and the ink fountain. A doctor blade provided so as to be able to advance and retreat with respect to the outer periphery of the ink forming roller, wherein the thickness of the ink adhering to the outer periphery of the ink forming roller is adjusted by the doctor blade. A shield plate having a length extending between the pair of side plates is provided in the ink reservoir so that the lower end thereof is close to the outer periphery of the ink forming roller, and an ink outlet is provided between the lower end of the shield plate and the upper surface of the bottom plate of the ink fountain. That is, the formed configuration was adopted.

[0008] By adopting the above configuration,
Since the contact between the ink and the ink forming roller is limited to the ink located at the ink outlet, the contact area of the ink with the ink forming roller can be reduced as compared with the related art. For this reason, even if ink flows downward due to contact with the ink forming roller and a pressure is generated, the ink pressure is small, and the reduction of the pressure causes ink passing between the contact portion between the ink forming roller and the doctor blade. And the ink film having a substantially uniform thickness can be formed on the outer periphery of the ink forming roller.

Here, if the inking roller has a two-layer structure of an inner layer and an outer layer, and the hardness of the inner layer is set to 20 ° to 25 ° and the hardness of the outer layer is set to 40 ° or more, the distance between the inking roller and the doctor blade is increased. When paper dust enters, the inner layer is elastically deformed and the outer layer bends to allow the powder to pass, thereby preventing formation of streaks in the ink film adhering to the outer periphery of the ink forming roller.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. As shown, the ink fountain 1 includes a bottom plate 2 having an inclined upper surface, and a pair of side plates 3 provided on both sides thereof. The ink fountain roller 1 is opposed to the ink fountain 1, and an ink reservoir 5 is provided between the ink fountain roller 4 and the fountain 1.

The ink reservoir 5 is filled with ink, and the ink adheres to the outer periphery of the ink forming roller 4 rotating in the direction of the arrow. The deposited ink is made uniform by the scraping of a doctor blade 6 provided below the bottom plate 2, and is transferred to a printing plate on a plate cylinder 7 provided opposite the ink forming roller 4.

Here, the doctor blade 6 is supported so as to be able to move forward and backward with respect to the outer periphery of the ink forming roller 4, and is moved forward and backward by rotation of an eccentric cam 8 provided at the back thereof.

The inking roller 4 has an inner layer 4a and an outer layer 4b.
Since the doctor blade 6 is in contact with the outer layer 4b, the outer layer 4b is formed of a material having excellent wear resistance, such as urethane rubber, and has a hardness of 40 ° or more. The hardness of the inner layer 4a is lower than that of the outer layer 4b, and is about 20 ° to 25 °.

A shielding plate 9 is provided in the ink reservoir 5. The shielding plate 9 has a length extending between the pair of side plates 3 of the ink fountain 1, and a small gap of about 1 mm is provided between the lower end thereof and the outer periphery of the ink forming roller 4. An ink outlet 10 is provided between the lower end of the shielding plate 9 and the upper surface of the bottom plate 2 of the ink fountain 1. Here, the height of the ink outlet 10 is 10 mm or less, preferably 5 mm.
It is better to do the following.

As described above, the shielding plate 9 is provided in the ink reservoir 5.
By forming an ink outlet 10 between the lower end of the shielding plate 9 and the upper surface of the bottom plate 2 of the ink fountain 1, only the ink located at the ink outlet 10 comes into contact with the ink forming roller 4 only. Even if the ink flows downward due to the contact with the ink forming roller 4 to generate pressure, the pressure is small, and the reduction of the pressure causes the passage of the ink passing between the contact portions between the ink forming roller 4 and the doctor blade 6. By making the amount uniform, an ink film having a uniform thickness can be formed on the outer periphery of the ink forming roller 4.

Further, since the inking roller 4 has a two-layer structure of an inner layer 4a and an outer layer 4b, and the hardness of the inner layer 4a is lower than the hardness of the outer layer 4b, paper dust is generated between the inking roller 4 and the doctor blade 6. When it enters, the inner layer 4a is elastically deformed and the outer layer 4b is bent inward in the radial direction, so that paper dust can escape in the rotation direction of the ink applying roller 4.

[0017] For this reason, the occurrence of the inconvenience of streaking in the ink adhered on the ink forming roller due to the clogging of the paper powder is extremely reduced, thereby preventing the formation of streaks in the printed matter.

[0018]

As described above, in the present invention, a shield plate is provided in the ink reservoir, and an ink outlet is provided between the lower end of the shield plate and the upper surface of the bottom plate of the ink fountain, so that the ink is supplied to the ink forming roller. The contact area can be reduced, and even if the ink moves downward due to contact with the inking roller and a pressure is generated between the inking roller and the doctor blade, the pressure is small. The amount of ink that passes between the contact portions between the inking roller and the doctor blade is made uniform, and an ink film having a uniform thickness can be formed on the outer periphery of the inking roller.

Further, the ink forming roller has a two-layer structure of an inner layer and an outer layer, and the hardness of the inner layer is lower than the hardness of the outer layer, so that paper dust entering between the ink forming roller and the doctor blade can be rotated by the ink forming roller. You can escape in any direction. For this reason, the occurrence of the inconvenience of streaking in the ink film on the inking roller due to clogging of paper dust is extremely reduced, and the formation of streaks in printed matter can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of an ink supply device according to the present invention.

FIG. 2 is a sectional view showing a conventional ink supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink pot 2 Bottom plate 3 Side plate 4 Ink roller 5 Ink pool 6 Doctor blade 7 Plate cylinder 9 Shield plate 10 Ink outlet

Claims (3)

[Claims] 1. An ink fountain having a bottom plate and a pair of side plates, an ink forming roller for forming an ink reservoir between the ink fountain, and a doctor blade provided to be able to advance and retreat with respect to the outer periphery of the ink forming roller. In the ink supply device, wherein the thickness of the ink adhering to the outer periphery of the ink forming roller is adjusted by the doctor blade, a shield plate having a length extending between the pair of side plates is provided in the ink reservoir. An ink outlet provided between the lower end of the shielding plate and the upper surface of the bottom plate of the ink fountain, the lower end of which is provided close to the outer periphery of the ink forming roller. 2. The ink supply device according to claim 1, wherein the ink application roller has a two-layer structure of an inner layer and an outer layer, and the hardness of the inner layer is smaller than the hardness of the outer layer. 3. The hardness of the inner layer is set to 20 ° to 25 °,
The ink supply device according to claim 2, wherein the hardness of the outer layer is 40 ° or more.