JPS6219315B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an apparatus for processing the plate surface of an offset master used in offset printing, and more particularly to an apparatus for etching (or making hydrophilic) the plate surface of an offset master. When applying an offset master image formed by a plate-making machine, the offset master plate surface is
It is well known that an etching process is necessary to apply an etching solution to make the non-image area hydrophilic while keeping the image area lipophilic. If this process is incomplete, printing ink may stain the non-image area during offset printing, resulting in a poor print finish, or
Once formed, the hydrophilic surface (hydrophilic chemical conversion film) in the non-image area is gradually destroyed, resulting in an incomplete interface balance between the hydrophilic surface and the oleophilic surface, which may reduce the print durability of the offset master. This problem arises. As described above, the etching process occupies an important position in the offset printing process. However, in the conventional etching process, manual etching was the mainstream, but many automatic etching devices have now been devised. For example, the first example is a device that simply immerses the offset master in an etching treatment tank, and the second example is a device that provides a rubbing function inside the etching treatment tank using a rubber or sponge roller, etc., which is either fixed or has a varying roller rotation speed. , Offset Master A device for improving the etching performance of plate surfaces (for example, see JP-A-52-42378). As a third example, the entire etching tank is heated using a heat source such as a heater to raise the temperature of the etching solution. An apparatus for etching using a method (see Japanese Utility Model Application Publication No. 72102/1983) has been proposed. However, these etching devices have a number of problems. For example, the device of the first example requires a long processing time to perform a sufficient etching process, and is significantly inferior in workability, while the device of the second example forcibly applies friction to the offset master plate surface. Therefore, there are drawbacks such as scratches on the plate surface and transportation troubles. In addition, the third example of the device heats the entire etching treatment tank, so it takes a long time to reach the appropriate processing temperature, and a large amount of heat capacity is required. In addition, it is necessary to attach a device to stir the etching solution, which increases the size of the device and reduces work efficiency, and also promotes evaporation of the etching solution and decomposition of metal ion components contained in the etching solution due to heat. There are many unstable factors in the etching process, such as the fact that no equipment has yet been developed. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the conventional offset master etching techniques described above and to provide an etching apparatus that can perform offset master etching processing at high speed and efficiently. That is, according to the present invention, in a device for etching the plate surface of an offset master used in an offset printing press, the etching section of the etching device is divided into a first etching section and a second etching section, and the etching section is divided into a first etching section and a second etching section. A heat treatment section equipped with a heat source is provided in the middle of the section, the offset master that has passed through the first etching section is transported to the heat treatment section, the etched offset master is heat treated, and then the second etching section is carried out. There is provided an etching apparatus which is adapted to transport the etching material to another section for re-etching. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a drawing showing an example of an etching apparatus according to the present invention, in which an offset master 2 that has completed plate making with a plate making machine 1 is used to print a plate surface 2a on which an image has been formed.
The paper is conveyed to the etching device 3 along the insertion guide plate 4 with the paper facing upward. The transported offset master 2 enters the first etching section 5, but the first etching section 5 has a processing liquid tank 15A containing an etching processing liquid 6, and one set is stored in this processing liquid tank 15A. Alternatively, a plurality of pairs of etching rollers 7a and 7b (two pairs are shown in FIG. 1) are provided, and at least a part of the etching roller 7b is exposed to the etching treatment liquid 6.
The upper roller 7a of this pair of etching rollers must be made of at least a material that can sufficiently absorb the etching solution 6 and that does not damage the plate surface of the offset master, such as porous non-woven fabric, felt, etc. Consists of. The lower roller 7b may be made of the same material as the upper roller 7a, but it is preferably made of a rubber roller that has excellent wear resistance, has a certain degree of hardness, and can enlarge the contact surface with the upper roller. It's okay. In the apparatus of the present invention, a heat treatment section 8 is provided adjacent to the first etching section 5 . This heat treatment section 8
A heat source 9 is attached to the upper position of the offset master, which is composed of a lamp heater, a nichrome wire heater, a panel heater, a hot roll heater, etc. It is configured to heat 2. The heat source 9 is covered with a reflective shade 12. In addition, a heat shielding plate 11 is provided to surround the heat treatment section 8.
is provided, so that heating is performed effectively only within the heat treatment section 8 and has the effect of preventing the internal temperature of the first etching section 5 and the second etching section 14 from rising due to heat conduction. . Furthermore, a heat dissipation port 13 is provided at the top of the heat treatment step 8, and the heat dissipation port 13 is made of a lath plate or the like, and surplus heat is radiated to the outside from here. Following the heat treatment section 8, a second etching section 14
is provided, and has a processing liquid tank 15B containing an etching processing liquid 6, and in this processing liquid layer 15B, one or more pairs of etching rollers 7a,
7b (two sets in the example of FIG. 1) are provided,
At least a portion of the etching roller 7b is immersed in the etching treatment liquid 6. The material of this pair of etching rollers is the same as that of the first etching portion 5 described above.
The rollers may be the same as those used in , or may be different. The processing liquid tank 15B is connected to the processing liquid tank 1 in the first etching section 5 through a connecting hose 16.
5A, thereby making it possible to replenish or drain liquid all at once, making it convenient to handle. Second etching part 1
A paper discharge chute 17 is provided on the paper discharge side of 4.
This can be connected directly to the printing press 18. Next, to make the functions of the above embodiment more specific, the offset master 2 that has completed the plate making inserts the insertion guide plate 4 with the image-formed plate side facing up.
, and is sent to the first etching section 5, where it is coated with an etching treatment liquid 6 while being conveyed by a plurality of rotating pairs of etching rollers 7a and 7b.
The etched offset master 2 is transported along a guide 10 to a heat treatment section 8 and heated by a heat source 9. To briefly explain the heat treatment conditions in the heat treatment section 9, the conditions of the capacity of the heat source, the distance between the master surface being transported and the heat source, and the speed at which the master is transported are based on the absorption rate of the etching liquid applied to the master surface per unit time. The degree of acceleration of the etching reaction differs depending on the heat capacity.
The conditions and conveyance speed of the heat treatment section must be set so that the master surface temperature during heat treatment rises to 40°C or higher. This heat treatment accelerates the etching reaction on the offset master plate. Further, since this heating only needs to be applied to the offset master 2 and the etching liquid applied to the plate surface thereof, the capacity of the heat source can be small and the heating can be performed quickly. Furthermore, in the apparatus of the present invention, this heat treatment section 8 and both etching sections 5 and 14 are separated, so that the etching treatment liquid 6 is not heated. This can be effectively prevented from occurring. The heated offset master 2 is then conveyed to the second etching section 14, and is conveyed by the rotation of a plurality of pairs of etching rollers 7a and 7b in the second etching section 14, and is etched again. Therefore, the etching reaction is further promoted and a sufficient etching process is completed. The offset master etched as described above is conveyed to a printing process 18 via a paper discharge chute 17. FIG. 2 is a diagram showing another embodiment of the etching apparatus according to the present invention, in which the first etching section 5 and the second etching section 14 in the embodiment of FIG. 1 are replaced by a pair of etching rollers. Instead of applying an etching solution to the offset master and etching it, we used the offset master 2.
The structure is such that the film is etched by being immersed in an etching solution 6. The rest of the structure of the device is the same as the embodiment of FIG. In this case, the transport roller 1
The material 9 may be a rubber roller or other material that is not eroded by the etching solution. Although not shown in the drawings, the first and second etching parts 5 and 14 of the embodiment shown in FIG. Also good. FIG. 3 is a drawing showing still another embodiment of the etching apparatus according to the present invention. In this example, the offset master 2 that has completed plate making is placed on the first plate with the plate surface 2a on which the image is formed facing downward. This is an embodiment in which the printing plate 2a of the offset master 2 is inserted into the etching section 5, and since the printing plate 2a of the offset master 2 is coated with the etching liquid by the roller 7a below the etching roller, it has the advantage that the coating ability is further improved. The rest of the structure of the device is the same as the embodiment of FIG. In addition, in the heat treatment section 8 of the embodiments shown in FIGS. 1, 2, and 3, the heat source 9 is
Although it is arranged to heat the plate surface 2a of the offset master 2 during transport, the heat sources may be arranged both above and below the offset master 2 in order to enhance the heating effect. As is clear from the above description, according to the etching apparatus of the present invention, the plate surface of the offset master is processed in the etching section divided into two, and the heating processing section located in the middle between the two etching sections is processed. By heating, the etching reaction is accelerated, and a sufficient etching process can be performed even in a short period of time.Moreover, the etching process itself is not affected by adverse effects such as evaporation of the etching processing liquid due to heating. High-speed automatic processing becomes possible. In addition, in the above embodiment, the offset master heating temperature of the heat-treated member can be easily adjusted by increasing or decreasing the power capacity of the heating source, or by increasing or decreasing the distance between the heat source and the master during which the heat treatment section is being transported. It can be changed to By varying the heating temperature of this master, it is possible to change the degree of progress of the etching reaction between the master and the etching treatment solution.For example, depending on the ambient temperature, the temperature of the etching treatment solution may vary, and the degree of progress of the etching reaction can be changed. Even when fluctuations occur, the etching reaction can always proceed at a constant rate by adjusting the heating temperature of the master in accordance with the temperature of the etching solution. Furthermore, even if it is desired to change the degree of progress of the etching reaction due to differences in offset masters, etc., this can be done by adjusting the heating temperature of the master. It goes without saying that there may be only one set of etching rollers in the processing liquid tank, and that there may be no communication between the processing liquid tanks. Next, the etching performance of the above embodiment of the etching apparatus according to the present invention and the conventional etching apparatus was evaluated by testing the etching ability of the apparatus and the fatigue of the etching solution using a Toko 810 desktop offset printing machine. . In addition, the test method and equipment used in the test are as follows. (1) Processing time and etching ability test Etching liquid is put into each etching device, and after confirming uniform coating performance, the image-formed master is used as a plate material, and the processing time (conveying speed) is set in the etching device. After changing the etching process, 2000 sheets were printed using an offset printing machine, and the finish of the prints (ink stains,
image reproducibility). (2) Etching liquid fatigue test A certain amount of etching liquid (1 in this test) was put into each etching device, and a liquid replenishment device was attached to control the liquid level.
A 5-day running test was conducted under the conditions of processing 100 imaged masters per day under the optimum transport speed conditions of each etching device, and in order to constantly check the degree of fatigue of the etching solution. For every 50 plates processed, 2000 sheets are printed using an offset printing machine, the etching ability is evaluated, and the maximum number of plates that can be processed per one etching solution is determined from the relationship between the amount of etching solution consumed and the etching capacity. Next, the equipment used in the test is as follows. (1) Printing machine...Toko 810 desk offset printing machine. (2) Plate material and etching liquid...manufactured by Iwatsu. The results are shown in the table below.

[Table] As explained above, the present invention has the advantage of shortening the etching time of the offset master, minimizing fatigue of the etching solution, and efficiently performing uniform etching at high speed. Etching equipment can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an etching apparatus according to the present invention, and FIG. 2 is a sectional view showing another embodiment of the present invention.
FIG. 3 is a sectional view showing still another embodiment of the present invention. 1... Plate making process, 2... Offset master,
2a... Plate surface, 3... Etching device, 4... Guide plate, 5... First etching step, 6... Etching treatment liquid, 7a, 7b... Etching roller, 8... Heat treatment step, 9... Heat source, 10...
Guide plate, 11...Heating plate, 12...Reflector, 13...Heat release plate, 14...Second etching process, 15A, 15B...Treatment liquid tank, 16...Connection hose, 17... Paper ejection chute, 18...printing process, 19...transport roller.

Claims (1)

[Claims] 1. In a device for etching the plate surface of an offset master used in an offset printing machine, the etching section of the etching device is divided into a first etching section and a second etching section, and a heat source is installed in the middle section between the first and second etching sections. A heat treatment section is provided, and the offset master that has passed through the first etching section is conveyed to the heat treatment section, where the etched offset master is heat treated, and then conveyed to the second etching section where it is re-etched. An etching device designed to perform etching.