JPH03239546A - Roller for printing machine and said printing machine - Google Patents

Abstract

PURPOSE:To prevent occurrence of crack in rollers while retaining a high hardness and wear resistance thereof by forming a coat by nickel alloy plating on the surface of a printing roller, through which printing paper is passed in contact therewith after being printed by a guide roller and common impression cylinder. CONSTITUTION:Since a roll paper moves at high speed, it travels through guides 6b-6m and reaches a common impression cylinder 11 of a color printing rotary press unit 3, before the black ink printed on its back side by a black ink print ing rotary press unit 2 becomes dry. At this time, the guides 6b, 6e, 6i and 6k are in contact with the printing face of the roll paper P1. A nickel alloy plating coat is also formed on the guide 6c in order to effect a simultaneous two face printing by the rotary press unit 2 on the surfaces of the guide 6b located in a printing paper feeding passage immediately after the printing has been made by a blanket cylinder 9 of the rotary press unit 2. This coat is formed through plating of nickel based alloy and the metal elements useable therefor are molybdenum, tungsten, cobalt, phosphorus, boron and iron.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roller used in a rotary printing press or the like, and a printing machine using the same roller.

[Conventional technology]

For example, in a color rotary printing press for in-membrane newspaper printing, a roll of paper is first passed between a pair of blanket cylinders in a black printing unit, and one side is printed in black and white.
Next, in the color plate unit, the other side is printed in color by sequentially passing between the common impression cylinder and the blanket cylinders corresponding to each color. Further, the paper roll advances while being guided by a plurality of guide rollers arranged along the paper conveyance path.

When color printing is performed using a roll of paper in this manner, the printed surface becomes dirty as the number of printed sheets increases. this is,
Regardless of offset printing or letterpress printing, a mixture of ink and paper powder is used as the guide roller.

This is because dirt adheres to the surface of the common impression cylinder etc. (hereinafter simply referred to as roller), and this dirt adheres to the web that passes through it.

Particularly in the case of color printing, if dirt adheres to the paper surface, the quality of the print will be significantly reduced.

Therefore, in the past, the printing press was stopped after a certain number of copies were printed, for example, every 150,000 copies, and an operator manually cleaned the surface of the roller with a solvent, or the surface of the roller was automatically cleaned using an automatic cleaning device. .

[Problem to be solved by the invention]

However, when printing a very large amount, such as with a newspaper printing machine, it is necessary to stop the printing machine several times a day to perform cleaning work, and the printing work slows down during this cleaning work. Resulting in. Further, it is not preferable from the viewpoint of safety for the operator to perform the cleaning work manually. Further, if an automatic cleaning device is used, the safety problem is eliminated, but there is a problem that it is very expensive and therefore not economical.

Therefore, an object of the present invention is to make it difficult for dirt to adhere to the surface of the roller.

[Means to solve the problem]

In order to achieve the above object, the printing press roller of the present invention has the following features:
It is characterized by having a nickel-based alloy plating film.

The nickel-based alloy plating film is made of molybdenum or tungsten whose main component is nickel.

Alloy plating coatings with cobalt, phosphorous, boron or iron can be used.

Furthermore, in order to achieve the above object, the printing machine of the present invention has a method in which the printing surface of the paper after single-sided printing comes into contact with the surface of a guide roller that guides the paper by contacting the printed surface of the paper after single-sided printing. The present invention is characterized in that a nickel-based alloy plating film is formed on the surface of a common impression cylinder to which a plurality of blanket cylinders are pressed against each other through the paper.

[Effect]

First, consider the cause of dirt adhering to the rollers.

In conventional printing presses, the surfaces of rollers such as guide rollers and common impression cylinders are coated with chrome plating in order to ensure sufficient hardness and increase wear resistance. If you look closely at the surface of this chrome plating, you will see countless tiny cracks spread across the entire surface. Since the chrome plating film has high internal stress, cracks occur in the chrome plating film due to the movement of releasing the stress. This crack has a width of 0
．． With a thickness of 0.01 to 0.03 μm, the crack spreads over the entire surface in a shell shape and becomes the crack.

During printing, the surface of the roller comes into contact with the web and the undried ink printed thereon, so that the ink soaks into the cracks and paper dust also mixes in, resulting in stains. Therefore, if the web comes into contact with the surface of the roller, the web becomes dirty.

Therefore, in order to avoid contamination,
The plating film must be made of a material that will not cause cracks. For example, as a plating film that does not cause cracks, it is conceivable to use a nickel plating film whose internal stress is lower than that of a chromium plating film. Nickel plating has no cracks, and because it does not have cracks, it has better corrosion resistance than chrome plating. However, plating with nickel alone has poor hardness and wear resistance.

Therefore, in the present invention, the surface of the roller is coated with nickel-based alloy plating. When other metal elements such as molybdenum are mixed into nickel, the crystal structure changes, improving wear resistance, hardness, and corrosion resistance. Therefore, if printing is performed using a roller whose surface is coated with nickel-based alloy plating, there will be no cracks on the surface of the roller, making it difficult for dirt to adhere to the roller. Also, even if it gets attached,
It does not seep into the interior, so it can be easily removed.

〔Example〕

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, features of the present invention will be specifically described based on examples with reference to the drawings.

FIG. 1 is a schematic diagram of an embodiment of a color printing press using the printing press roller of the present invention.

The color printing machine includes a rotary printing unit 2 for ink printing and a rotary printing unit 3 for color printing, which are provided adjacently on a machine bed 1, and a paper feeder 4 that supplies web P to these rotary printing units 2.3. It is composed of. A paper roll 5 is attached to the paper feed device 4.

A blank paper roll P pulled out from the paper roll 5 is guided to the ink printing rotary printing unit 2 via a plurality of guide rollers 5a, 5a, . The rotary printing unit 2 for ink printing is provided with two sets of plate cylinders 7, 8 and a blanket cylinder 9.10, and the web P passes between the pair of blanket cylinders 9.10 and is printed on one side, for example, on the back side. Printed with black ink. In addition, when performing color printing by using the rotary printing unit 2 for ink printing and the rotary printing unit 3 for color printing, only one plate cylinder 7 and plancher (UA9) are used, and the other plate cylinder 8 and blanket are used. The torso 10 is used as a dummy.

The web P1 after printing on the back side is moved by a plurality of guide rollers 6b.
~6ITl to the printing section of the rotary printing unit 3 for color printing. The rotary printing unit 3 for color printing is provided with four sets of plate cylinders 12 to 15 and blankets TlAl6 to 19 for a common impression cylinder 11, and between the common impression cylinder 11 and each blanket cylinder 16 to 19. The roll paper P
(2) passes in sequence, and the other side, for example, the front side, is sequentially printed with yellow, magenta, two cyan, and black inks.

Therefore, from the rotary printing unit 3 for color printing, a web P whose back side is printed in black and the front side is printed in four colors is obtained. The paper roll P2 after double-sided printing is further sent to a folding machine (not shown) via guide rollers 6n, 6p to 6S.

In the above-mentioned color printing machine, the web moves at a high speed of about 8 to 10 m/s, so the guide guides 6b to
6ITl and reaches the common impression cylinder 11 of the rotary printing unit 3 for color printing. At this time, the guides 5b, 6e
, 5i, (ik is the roll paper P, (7) There is a risk that the surface of the guide will get dirty because it comes into contact with the printed surface. Therefore, at least the ink printing in these guides 6b, 6e, 6i, 6. A coating of nickel-based alloy plating is formed on the surface of the guide guide 6b located on the paper conveyance path immediately after printing by the blanket cylinder 9 of the rotary printing unit 2.In this embodiment, the guide guides 5b, 5i , 5k is coated with a nickel-based alloy plating film.In addition, as will be described later, in order to perform double-sided printing simultaneously with the ink printing rotary printing unit 2, a nickel-based alloy plating film is also formed on the guide guide 6C. is forming.

FIG. 2 shows the structure of each of the guides as a representative of the guide roller 20, and the surface of the core 210 made of steel such as 545C or STKM16 is coated with a thickness of 0.2 to 0.3 mm, for example, Q, 3 mm thick. , nickel-based alloy plating film 22
is formed. This film 22 is a plating film alloyed with nickel as a base, and usable metal elements include molybdenum, tungsten, cobalt-1-phosphorous,
Contains boron and iron.

The composition ratio in a nickel alloy plating film changes depending on various factors, but basically the internal stress of the plating film is related to the occurrence of cracks, so excessive mixing is not a good idea as it will cause cracks to occur. do not have. However, in order to ensure hardness and abrasion resistance equivalent to those of conventional chrome plating, the composition ratio of the coating needs to be in accordance with these characteristics.

The composition ratio of the nickel-based alloy plating film in this example is as follows.

Nickel-molybdenum alloy plating is a plating film containing 1 to 10% by weight of molybdenum in nickel.

Nickel-tungsten alloy plating is a plating film containing 3 to 40% by weight of tungsten in nickel.

Nickel-cobalt alloy plating is a plating film containing 5 to 30% by weight of cobalt in nickel.

In nickel-phosphorus alloy plating, 5 phosphorus is present in nickel.
Plating film containing ~15% by weight.

Nickel-boron alloy plating is a plating film containing 2 to 10% by weight of boron in nickel.

In nickel-iron alloy plating, there are 5 to 2 iron in nickel.
Plated film containing 5% by weight.

By using the above nickel alloy plating film,
The internal stress of the plating film can be reduced while maintaining high hardness and wear resistance. Therefore, cracks do not occur in the plating film, and stains caused by ink and paper dust are less likely to adhere to the surface of the guide roller 20.

Therefore, by conveying the web using the guide roller 20 on which the nickel-based alloy plating film 22 is formed, dirt is less likely to adhere to the web.

Further, since the common impression cylinder 11 of the rotary printing unit 3 for color printing also comes into contact with the printing surface of the web P+, there is a risk that the surface thereof may become dirty. Therefore, a nickel-based alloy plating coating is formed on the surface of the common impression cylinder 11, similarly to the guide roller.

FIG. 3 shows the structure of the common impression cylinder 11, in which a nickel-based alloy plating coating 32 is coated on the surface of a core 31 made of steel.
is formed. This coating 32 is a plating coating made of a nickel-based alloy, and its composition is the same as that of the guide roller.

Therefore, dirt is less likely to adhere to the surface of the common impression cylinder 11, and the back surface of the web P1 that contacts the common impression cylinder 11 is less likely to become dirty.

Further, a guide roller 6n located after the common impression cylinder 11.

Since 6p to 6S come into contact with either the front or back printed surface, these guide rollers may be coated with nickel-based alloy plating to prevent staining.

As mentioned above, by forming the nickel-based alloy plating coatings 22 and 32 on the surfaces of the guide roller 20 and the common impression cylinder 11 that rotate in contact with the printed surface of the web, dirt is less likely to adhere to these surfaces. Become.

Therefore, the interval between cleaning the rollers can be increased. Furthermore, since nickel-based alloy plating has better corrosion resistance than chrome plating, the life of the roller itself is extended.

According to operational results, color printing was performed by forming a nickel-based alloy plating film on the guide rollers 6b, 6c, 6i, and 6 of the guide rollers shown in FIG. 1 and on the surface of the common impression cylinder 11. Even after printing 3 million to 5 million copies or more, there is still no need for cleaning. In contrast, conventional guide rollers and common impression cylinders on which chrome plating was formed required cleaning approximately every 150,000 copies.

Note that although the above-described embodiments have been described using color printing as an example, the above-described printing machine can also be used to perform ordinary black printing.

In this case, by operating both the two sets of plate cylinders 7.8 and blanket cylinders 9.10 in the rotary printing unit 2 for ink printing, when the web passes between the pair of blanket cylinders 9.10, both sides can be is printed in black ink at the same time. In this case, since the printed surface also comes into contact with the guide roller 6C, a chrome plating film is also formed on this guide roller 6C. Therefore, even when printing in only black, the guide roller is less likely to get dirty, and printing without stains can be performed. Note that the roll of paper printed on both sides by the rotary printing unit 2 for ink printing is sent directly to the folding machine without passing through the rotary printing unit 3 for color printing.

〔Effect of the invention〕

As described above, according to the present invention, a nickel-based alloy plating film is formed on the surface of the printing roller, such as the guide roller and the common plate cylinder, through which the printed paper passes while being in contact with it. Cracks can be prevented while maintaining wear resistance. Therefore, dirt is less likely to adhere to the surface of the roller, and the paper is not stained by dirt on the roller.

Particularly in the case of color printing, stains on the paper significantly reduce the quality of printing, so by preventing this stain, high quality color printing can be performed. Furthermore, corrosion resistance is improved compared to conventional chrome plating. Furthermore, since the rollers are less likely to get dirty, the number of times the rollers need to be washed can be reduced, and the stagnation time of the printing work caused by the washing work is shortened, making it possible to improve work efficiency.

Furthermore, since the frequency of cleaning work is reduced, it is possible to handle large-volume printing without introducing an expensive automatic cleaning device.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing an embodiment of the printing press of the present invention, FIG. 2(a) is a perspective view of a guide roller used in the printing press, and FIG. 2(b) is a sectional view of the guide roller. , Figure 3 (
1A is a perspective view of a common impression cylinder used in the printing press shown in FIG. 1, and FIG. 1B is a sectional view of the same common impression cylinder. 1: Machine bed 2: Rotary printing unit for black printing 3: Rotary printing unit for color printing 4: Paper feeding device 5: Paper rolls 6a to 6n,
6p-6s, 20: Guide roller 7.8: Plate cylinder 9.10.16-19: Blanket cylinder 11: Common impression cylinder 12-15: Plate cylinder 21.31: Core 22.32: Nickel-based alloy plating coating P , Pl+
P2: Rolling paper

Claims (1)

[Scope of Claims] 1. A roller for a printing press, characterized by having a nickel-based alloy plating film. 2. The nickel-based alloy plating film contains molybdenum, tungsten, cobalt, phosphorus, nickel as a main component,
The roller for a printing press according to claim 1, characterized in that the coating is an alloy plating coating with boron or iron. 3. A printing machine characterized in that a nickel-based alloy plating film is formed on the surface of a guide roller that guides the paper by contacting the printing surface of the paper after single-sided printing. 4. A printing machine characterized in that a nickel-based alloy plating film is formed on the surface of a common impression cylinder with which the printing surface of the paper after single-sided printing comes into contact and a plurality of blanket cylinders are pressed against each other via the paper.