JPH10250208A - Rotary mimeograph printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a sufficient amount of ink to a printing drum, and to recover excess amount of ink to the drum by arraying to form grooves extended along a periphery of an ink coating roller on a surface of the roller substantially uniformly in an axial direction of the roller. SOLUTION: Grooves 222 formed on a surface of a coating roller 18 are spirally extended axially of the roller 18 on the outer periphery in a range from one end to the other end of the roller 18. Ink transferred to the roller is adhered to the surface of the roller 18, and introduced into the grooves 22 to be held in sufficient amount as necessary supply amount so that the ink holding amount corresponds to a rubber roller. Excess ink is transferred over a contact point of the roller 18 with a printing drum while remained adhered to the surface of the roller 18. That is, the excess ink on the roller 18 is again arrived at an opposite contact point with the ink roller, substantially completely recovered here, and returned to an ink reservoir.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transfer printing press, and more particularly to a rotary transfer printing press provided with an ink applying roller for applying ink to a printing drum by contacting the inner peripheral surface of the printing drum.

[0002]

2. Description of the Related Art Generally,
In a rotary transfer printing press, a rubber press roller is in contact with at least the surface of a printing drum composed of a sheet-shaped metal mesh, and ink is applied to the inner peripheral surface of the printing drum at the contacting point. A roller (hereinafter, simply referred to as an application roller) is in contact with the roller.

When the print drum rotates, the application roller also rotates at a predetermined speed in the same direction as the print drum. If the peripheral speeds of the two are relatively equal or the peripheral speed of the application roller is higher, an amount of ink necessary for printing is transferred from the application roller to the printing drum, and unnecessary or excessive ink is removed from the application roller. Is separated from the printing drum (hereinafter, referred to as an exit side) and collected while being attached to the application roller. However, when the peripheral speed of the application roller is faster than the peripheral speed of the print drum, the ink supply becomes excessive, and the application roller contacts the print drum (hereinafter referred to as the entrance side). An ink pool will be formed. Conversely, if the peripheral speed of the application roller is lower than the peripheral speed of the printing drum, the ink supply will be insufficient.

As described above, in order for ink to be transferred between the application roller and the printing drum without excess or deficiency, the relative speed difference between the peripheral speeds of the two must be kept within a predetermined range. , Its allowable range is relatively narrow.

[0005] In addition, in printing, the beauty is increased by transferring a sufficient amount of ink to the paper sharply. However, if the amount of ink is too large, bleeding appears and the sharpness is maintained. It becomes difficult, and beautiful printing cannot be obtained simply by increasing the ink supply amount. It is also important for the beauty that the ink is evenly distributed on the paper.

SUMMARY OF THE INVENTION In view of the above technical problems, the present invention can supply a sufficient amount of ink to a printing drum, and collects an excessive amount of ink on the printing drum. An object of the present invention is to provide a rotary transfer printing press capable of printing.

[0007]

SUMMARY OF THE INVENTION A rotary copying machine according to the present invention has the following arrangement in order to solve the above-mentioned problems of the prior art and to achieve the object. That is, in a rotary transfer printing press provided with an ink application roller for supplying ink to the print drum by contacting the inner peripheral surface of the print drum, a groove extending along the periphery of the roller on the surface of the ink application roller. Are arranged substantially uniformly in the axial direction of the roller.

[0008] The groove is inclined with respect to the axial direction of the coating roller, and is preferably formed in a spiral shape.

[0009]

In the rotary transfer printing press according to the present invention, since the groove is formed on the surface of the application roller, the ink is applied while adhering to the surface of the application roller and also entering the groove. It is sandwiched between the roller and the printing drum. Therefore, a larger amount of ink can be supplied without overflowing between the roller and the drum than the application roller having no groove. That is, the ink holding force is increased as compared with the coating roller having no groove, and the printing roller can contact the printing drum while holding a large amount of ink. Can be supplied sufficiently. Also, the collected ink can be accommodated in the groove, so that even if there is a large amount of excess ink, it can be sufficiently collected.

[0010] In particular, the ink holding power is given by the total length and depth of the groove. The deeper the groove and the longer the groove length, the higher the ink holding force of the application roller. However, the ink pulling force for collecting the ink is mainly provided by a flat portion between adjacent grooves. The flat portion between the grooves is a surface perpendicular to the direction of the surface tension that pulls the ink, and constitutes a surface that attracts the ink most strongly. Therefore, if the flat portion is reduced, the ink collecting power becomes insufficient.
That is, if the area density occupied by the grooves on the surface of the application roller is increased without bound to increase the groove length, the ratio of the flat portion between the grooves to the surface of the application roller is reduced, and the ink recovery power is reduced. Becomes lower.

If the groove is inclined with respect to the axial direction of the coating roller, the ink spreads substantially evenly over the entire width of the inner peripheral surface of the printing drum when the coating roller rotates, so that the printing surface has a dark portion with a large amount of ink. Thin portions with a small amount of ink do not appear as stripes.

As described above, if grooves are formed around the application roller at appropriate arrangement intervals, ink can be sufficiently supplied to the printing drum so as to enable beautiful printing, and that the ink between the roller and the drum can be supplied. The excess ink can be reliably collected without overflowing from between. Therefore, regarding the control of the relative peripheral speed difference between the roller and the drum,
Even if this is roughly performed, an appropriate ink supply amount can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary printing press according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory diagram showing a schematic configuration of a rotary copying machine according to the present embodiment. In the figure, 1 is a printing drum, 2 is a press roller, 3 is a stencil discharging mechanism, 4 is a stencil roll, 5 is a plate making thermal head, 6 is a stencil made, 8 is a press roller driving mechanism,
9 _1, 9 _2, 9 ₃ each print sheet tray, 10 paper feed mechanism section, 11 paper discharge receiving portion, 12 is a document reading unit.

On the printing drum 1, a base paper clamper 13 for receiving the base paper produced by the thermal head 5 and holding the leading end of the base paper, and the leading end of the base paper discharged after the target printing is completed. A base paper jumping lever 14 to be introduced into the base paper discharge mechanism 3 is attached.

In the printing drum 1, as shown in FIG.
An ink application mechanism is built-in, and ink is supplied from the inside to the drum 1 on which the base paper is mounted, between the surface of the drum 1 and the base paper. The printing drum 1 is made of a flexible sheet-shaped metal mesh in a cylindrical shape so that the ink supplied from the inside is sufficiently adapted, and has sufficient flexibility. It is the application roller 18 of the ink application mechanism that substantially receives the pressure of the press roller 2 at the contact portion between the printing drum 1 and the press roller 2. In addition,
In this embodiment, the printing drum 1 and the press roller 2 have the same diameter and rotate at the same speed. Accordingly, a relief recess 15 is formed at a position on the press roller 2 which is always synchronized with the base paper clamper 13 and the base paper flip-up lever 14 protruding on the printing drum 1 so as not to interfere therewith.

The application roller 18 is a roller which is in contact with the printing drum 1 and supplies ink to the inner peripheral surface of the printing drum 1 while rotating at substantially the same peripheral speed in the same direction, and is made of metal or relatively hard. It is made of a synthetic resin and has a groove 22 formed on the surface thereof as shown in an enlarged sectional view of a main part of FIG. The groove 22 extends helically on the outer periphery of the coating roller 18 over a range from one end to the other end in the axial direction.

The cross-sectional shape of the groove 22 is substantially triangular, its width is about 0.2 mm and depth is about 0.1 mm, and the density on the roller surface is 10 per 1 cm of the axial length of the roller. Good degree. If more than that,
The ratio of the flat portion between the grooves to the surface area is low and the ink collecting power is insufficient. If the ratio is small, the ink holding power is low and the advantage of the groove formation is not sufficiently exhibited. In addition,
Since the groove 22 is formed in a spiral shape, the coating roller 18
When is rotated, the ink is distributed almost uniformly over the entire width of the inner peripheral surface of the printing drum 1, and a dark portion having a large amount of ink and a thin portion having a small amount of ink do not appear as stripes. Even if a large number of elliptical grooves inclined with respect to the axis of the roller 18 are formed, the ink can be spread evenly in the same manner.

In the case of a metal roller, in particular, it does not swell or deteriorate due to ink, unlike the case of a rubber roller, and is excellent in durability and printing quality stability. The groove on the roller surface is particularly effective for increasing the ink holding power in the case of a roller made of a material having relatively low affinity for ink, such as a resin roller or a metal roller.

The ink is supplied between the ink roller 19 and the squeegee roller 20 to form an ink reservoir 21 there. Ink roller 19 and squeegee roller 20
Are both metal rollers, which circumscribe each other. A fine groove is formed on the surface of the squeegee roller 20 with high dimensional accuracy, and the ink supply amount is accurately controlled by a gap formed between the two rollers in the groove. Further, the ink moves from the ink roller 19 to the application roller 18, but since both rollers 18 and 19 are circumscribing while rotating in the same direction, the outer peripheral surfaces of the rollers advance in the direction in which the outer peripheral surfaces oppose each other. And therefore the ink roller 1
The ink on the outer peripheral surface 9 moves to approximately 100% of the application roller 18. The ink transferred to the application roller 18 is applied to the roller 1
At the same time, the ink adheres to the surface of the groove 8 and enters the groove 22 to hold a sufficient amount of ink as a necessary supply amount, and the ink holding amount is comparable to that of a rubber roller. That is, even with a metal roller, printing that is dense, clear, and beautiful can be performed almost as well as a rubber roller.

The surplus ink collected by the application roller 18 can be accommodated in the groove 22 on the surface of the application roller 18, so that even a large amount of excess ink can be dealt with, and the ink collection capacity has a margin. is there. Therefore, even if a large amount of ink is supplied to the printing drum 1 to perform dark printing and a large amount of surplus ink comes out, it can be sufficiently recovered and recovered, and the ink is prevented from overflowing the base paper. Enables dark and clear printing.

As described above, the application roller 18 is in contact with the printing drum 1 and rotates in the same direction at substantially the same peripheral speed, and only a necessary amount of ink is transferred to the printing drum 1. Excess ink is transported over the contact point between the application roller 18 and the printing drum 1 while adhering to the surface of the application roller 18. That is, the excess ink on the application roller 18 reaches the contact point facing the ink roller 19 again, where it is almost completely collected by the ink roller 19 and returned to the ink reservoir 21. In this way, no ink pool is formed on the back surface of the printing drum 1, and a good ink supply state can always be obtained for the printing drum 1.

By changing the peripheral speed ratio of the ink roller 19 to the application roller 18, the amount of ink transferred to the application roller 18 can be variably adjusted. For example, if the speed of the ink roller 19 is reduced by half, the amount of ink transferred from the ink roller 19 to the application roller 18 is also reduced by half.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a rotary copying machine according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a printing drum, an ink application mechanism, and a press roller in a rotary transfer printing press according to an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a main part showing grooves on the surface of an application roller in a rotary copying machine according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 printing drum 2 press roller 3 stencil discharging mechanism 4 stencil roll 5 plate making thermal head 6 stenciled stencil 8 press roller driving mechanism 9 printing paper tray 10 paper feeding mechanism 11 paper discharge receiving unit 12 original reading unit 13 stencil clamper 14 Base paper flip lever 15 Escape recess 18 Coating roller 19 Ink roller 20 Squeegee roller 21 Ink pool 22 Groove

Claims (2)

[Claims] 1. A rotary copying machine comprising an ink application roller (18) for supplying ink to the printing drum (1) by contacting the inner peripheral surface of the printing drum (1). A rotary printing press, characterized in that grooves (22) extending along the periphery of the roller are formed on the surface of the roller (18) so as to be arranged substantially uniformly in the axial direction of the roller (18). 2. The groove (22) is provided with an application roller (18).
2. The rotary printing press according to claim 1, wherein the printing press is inclined with respect to the axial direction.