JP2000127638A - Gravure printing plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure printing plate which has a long service life as compared with a conventional one, does not deteriorate the quality of a printed image by damaging the shape of fine cells, and does not cause the increase in production costs and a method for producing the gravure printing plate. SOLUTION: A gravure printing plate has a gravure printing plate main body having a surface 12b on which a cell 12c is formed and an abrasion resistant plating layer 14 of a chromium-carbon alloy with which the surface of the printing plate main body was plated and which is heat-treated at 300-600 deg.C. A method for producing the gravure printing plate comprises a process in which the cell 12c is formed on the surface 12b of the plate main body, a process in which the surface of the plate main body is plated with the alloy to form the layer 14, and a process in which the abrasion resistant plating layer of the alloy with which the surface of the plate main body was plated is heat- treated at 300-600 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gravure printing plate and a method for manufacturing the gravure printing plate. More specifically, the surface of a gravure printing plate body on which cells are formed is covered with a wear-resistant plating layer. The present invention relates to a gravure printing plate and a manufacturing method thereof.

[0002]

2. Description of the Related Art A cylindrical gravure printing plate body of a gravure printing plate used for gravure printing comprises an iron core and a copper plating surface layer surrounding the periphery of the iron core. On the surface of the surface layer, an image to be printed is formed by a large number of minute recesses called cells.

In gravure printing, ink is supplied to the surface of a cylindrical gravure printing plate body, and then the ink on the surface is scraped off by a doctor blade pressed against the surface of the cylindrical gravure printing plate body. Is filled with ink only in a large number of cells on the surface,
Finally, the ink in the large number of cells on the surface is transferred to a recording medium such as continuous paper.

[0004] In order to print a clear image in gravure printing, it is necessary to completely scrape the ink supplied to the surface of the cylindrical gravure printing plate body from other than the cells. It is pressed against the surface with high pressure. To prevent wear, the doctor blade is made of a material having a relatively high hardness, and the surface of the gravure printing plate body is also covered with a wear-resistant plating layer formed of hard chrome plating.
Usually, the wear-resistant plating layer of hard chromium is formed at a temperature of about 50 ° C. to 60 ° C. in an acidic bath called a surge bath, and has a crystalline structure.

[0005]

In the conventional gravure printing plate thus formed, the Vickers hardness of the hard chromium wear-resistant plating layer is approximately 800 HV to approximately 11 HV.
00 HV. Prolonging the service life of the gravure printing plate is dealt with by increasing the thickness of the wear-resistant plating layer of hard chromium. However, as the thickness of the hard chromium wear-resistant plating layer is increased, the shape of minute cells becomes unclear and the quality of the printed image deteriorates, and the plating time and plating material increase. Therefore, the production cost of the gravure printing plate is increased.

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and an object of the present invention is to provide a printed image having a longer service life than a conventional one without impairing the shape of minute cells and greatly reducing the quality of a printed image. Further, an object of the present invention is to provide a gravure printing plate and a method for manufacturing the gravure printing plate, which do not cause a significant increase in manufacturing cost.

[0007]

In order to achieve the above-mentioned object of the present invention, a gravure printing plate according to the present invention comprises:
A gravure printing plate body having a cell-formed surface;
Plating on the above surface of the gravure printing plate body, approximately 300 ° C
A wear-resistant plated layer of a chromium carbon alloy that has been heat-treated at a temperature of about 600 ° C. to about 600 ° C.

A gravure printing plate according to the present invention for achieving the above-mentioned object of the present invention comprises a gravure printing plate main body having a surface on which cells are formed, having a wear-resistant plating layer on the surface. And the Vickers hardness of the wear-resistant plating layer is 1300 HV or more.

Further, in order to achieve the above-mentioned object of the present invention, a method for producing a gravure printing plate according to the present invention comprises: a step of forming cells on the surface of the gravure printing plate main body; Plating a chromium carbon alloy on the surface to form a wear-resistant plating layer; heating the wear-resistant plating layer of the chromium carbon alloy plated on the surface of the gravure printing plate body at a temperature of about 300 ° C. to about 600 ° C. And a step of processing.

[0010] The wear-resistant plated layer of the chromium carbon alloy heat-treated as described above has a Vickers hardness of 1300 HV or more and up to about 1600 HV. Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0011]

FIG. 1 is a schematic longitudinal sectional view of a gravure printing plate according to one embodiment of the present invention; and FIG. FIG. 4 is a partial cross-sectional view showing an enlarged view of the periphery of one cell.

As shown in FIG. 1, a gravure printing plate 10 according to an embodiment of the present invention includes a gravure printing plate main body 12 having a cylindrical shape. Gravure printing plate body 12
Is composed of an iron core 12a and a copper plated surface layer 12b surrounding the iron core 12a. On the surface of the surface layer 12a, an image to be printed is formed by a large number of minute recesses 12c called cells.
The configuration up to this point is the same as the configuration of the columnar gravure printing plate main body of the conventional gravure printing plate, and the manufacturing method up to this point is the same as the conventional method of manufacturing the gravure printing plate main body. In FIG. 1, in order to clearly show a large number of minute recesses 12 c, each of the large number of recesses 12 c is drawn considerably larger than the entire size of the gravure printing plate main body 12.

As shown in FIG. 2, the surface of the gravure printing plate main body 12, ie, the surface of the surface layer 12a, is made of amorphous chromium formed by plating a chromium plating material containing carbon. It is covered with a wear-resistant plating layer 14 of a carbon alloy. It is known that the wear-resistant plated layer 14 of an amorphous chromium carbon alloy has a Vickers hardness of approximately 1200 HV.

More specifically, the wear-resistant plating layer 14 will be described.
In the bath containing oxalic acid, a chromium carbon alloy having a carbon content of about 1.5% to about 3% having a thickness of about 5 μm to about 10 μm is formed on the surface of the gravure printing plate body 12, that is, on the surface layer 12 a. It is formed by plating on the surface. Further, in this embodiment, the wear-resistant plating layer 14 is further placed in a hot air atmosphere at about 300 ° C. to about 600 ° C. for one hour or more together with the gravure printing plate body 12, heat-treated, and then cooled. As a result, the hardness of the wear-resistant plating layer 14 is
Vickers hardness is about 1300 HV to about 1600 HV.

The hot air heating treatment temperature is higher,
That is, the closer to 600 ° C., the more the wear-resistant plating layer 14
Although the hardness increases, the temperature is preferably about 350 ° C. in consideration of the time and energy required for the hot air heating treatment.

In order to examine the durability of an actual gravure printing plate manufactured according to the method for manufacturing a gravure printing plate of the present invention, the inventor of the present invention performed the following experiment. First, two gravure printing plate bodies are prepared in which a surface layer of copper plating having a thickness of 120 μm is formed on the surface of an iron core, and a large number of cells for a predetermined image are formed on the surface layer. I do. And one gravure printing plate body,
It does not follow the method of manufacturing a gravure printing plate of the present invention, and its surface is merely covered with a wear-resistant plating layer of an amorphous chromium carbon alloy containing about 2% of carbon to a thickness of about 8 μm. The other gravure printing plate main body is covered with a wear-resistant plating layer of an amorphous chromium carbon alloy containing approximately 2% of carbon in a thickness of approximately 8 μm similarly to the one gravure printing plate main body. According to the method of manufacturing a gravure printing plate of the present invention,
After being placed in a hot air atmosphere at about 350 ° C. for one hour and subjected to a heat treatment, it was allowed to cool.

Next, the two gravure printing plates produced in this way are incorporated into two similar gravure printing presses,
In each of the gravure printing presses, a 12-μm-thick stretched polyester film prepared as a recording medium was printed 2,000 meters using an aqueous white ink having a solid content ratio of 50% and a viscosity of 20 seconds (Zan cup # 3), and then The image printed on the stretched polyester film is not printed on the stretched polyester film, but the surface of the gravure printing plate is observed after rotating the gravure printing plate by an amount equivalent to printing 8000 meters on the recording medium. The step of measuring the amount of applied ink in a dry state was repeated.

The aqueous white ink used in this experiment has a particularly high coefficient of friction among various inks actually used for printing, and promotes the wear of the gravure printing plate most. From the results of the above-described experiments, it can be seen that the one gravure printing method was performed without following the method for manufacturing a gravure printing plate of the present invention and covered with a wear-resistant plating layer of an amorphous chromium carbon alloy that had not been heat-treated. In the plate, the exposure of the copper plating surface layer of the gravure printing plate body was observed when the plate was rotated by an amount equivalent to 200,000 meters, and the amount of ink applied at this time was the amount of ink applied at the first observation. Was reduced by about 38%.

However, the other gravure printing plate manufactured according to the gravure printing plate manufacturing method of the present invention and covered with the wear-resistant plating layer of the heat-treated amorphous chromium carbon alloy has a thickness of 280,000 meters. The observation of the copper plating surface layer of the gravure printing plate main body was observed by observation when rotated by a corresponding amount, and the ink application amount at this time was reduced by about 37% from the ink application amount at the first observation. I was Further, in the observation when rotated by an amount corresponding to 200,000 meters, the amount of applied ink was reduced by approximately 16% compared to the amount of ink applied when the first observation was made.

From the results of this experiment, it can be seen that the other gravure printing plate covered with a wear-resistant plating layer of an amorphous chromium carbon alloy manufactured and heat-treated in accordance with the method of manufacturing a gravure printing plate of the present invention. Compared with the other gravure printing plate, which is manufactured without following the method for manufacturing a gravure printing plate of the present invention and covered with an abrasion-resistant plating layer of an amorphous chromium carbon alloy which has not been heat-treated. It was found to have a durability four times higher.

[0021]

As is apparent from the above description, according to the gravure printing plate and the method of manufacturing the same according to the present invention, the copper plating surface of the gravure printing plate main body in which a large number of minute cells are formed. The thickness of the abrasion-resistant plating layer that covers the layer to improve the abrasion resistance during printing is made thinner than before so as not to impair the shape of the minute cells so that the quality of the printed image does not deteriorate. Nevertheless, the service life can be made longer than before, and the production cost does not increase significantly.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a gravure printing plate according to an embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing the periphery of one cell on the surface of the gravure printing plate of FIG. 1;

[Explanation of symbols]

 Reference Signs List 10 gravure printing plate 12 gravure printing plate main body 12a iron core 12b surface layer 12c recess (cell) 14 wear-resistant plating layer

Claims (3)

[Claims] 1. A gravure printing plate body having a surface on which cells are formed; and a chromium carbon alloy plated on the surface of the gravure printing plate body and heat-treated at a temperature of about 300 ° C. to about 600 ° C. A gravure printing plate comprising: a wear plating layer; 2. A gravure printing method, comprising a wear-resistant plating layer on the surface of the gravure printing plate body having a surface on which cells are formed, wherein the wear-resistant plating layer has a Vickers hardness of 1300 HV or more. Edition. Forming a cell on the surface of the gravure printing plate body; plating a chromium carbon alloy on the surface of the gravure printing plate body to form a wear-resistant plating layer; Heating the abrasion-resistant plating layer of a chromium carbon alloy plated at a temperature of about 300 ° C. to about 600 ° C. on a gravure printing plate.