JPH0698743B2 - Roller for printing machine and printing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a roller used in a rotary printing machine or the like and a printing machine using the roller.

[Conventional technology]

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

When color printing is performed using the roll paper, the printing surface becomes dirty as the number of printed sheets increases. this is,
This is because, regardless of offset printing or letterpress printing, a mixture of ink and paper dust adheres to the surface of the guide roller, the common impression cylinder, etc. (hereinafter simply referred to as a roller) and stains it, and this stain adheres to the passing paper roll. .

In particular, in the case of color printing, if the paper surface becomes dirty, the quality of printing will be significantly reduced.

Therefore, conventionally, the printing machine is stopped every fixed number of copies, for example, every 150,000 copies, and the operator manually cleans the surface of the roller with a solvent or automatically cleans it with an automatic cleaning device. .

[Problems to be Solved by the Invention]

However, when printing a very large amount of paper such as a printing press for newspaper printing, it is necessary to stop the printing machine several times a day to perform the cleaning work, and the printing work is stagnant during the cleaning work. Resulting in. In addition, it is not preferable in terms of safety that an operator manually performs the cleaning work. Further, if an automatic cleaning device is used, there will be no problem in safety, but there is a problem in that the economy is poor because it is very expensive.

Therefore, it is an object of the present invention to prevent dirt from adhering to the surface of the roller.

[Means for Solving the Problems]

The roller for a printing machine of the present invention, in order to achieve the above object,
It is characterized by having a nickel-based alloy plating film.

As the nickel-based alloy plating film, an alloy plating film containing nickel as a main component and containing molybdenum, tungsten, cobalt, phosphorus, boron or iron can be used.

In order to achieve the above-mentioned object, the printing machine of the present invention contacts the surface of a guide roller that guides the paper by contacting the printing surface of the paper after single-sided printing, or the printing surface of the paper after single-sided printing contacts. A nickel-based alloy plating film is formed on the surface of a common impression cylinder against which a plurality of blanket cylinders are pressed against each other via the sheet.

[Action]

 First, the cause of the dirt adhering to the roller will be examined.

In a conventional printing machine, a chrome-plated film is formed on the surfaces of rollers such as a guide roller and a common impression cylinder in order to secure sufficient hardness and enhance wear resistance. When the surface of this chrome plating is observed in detail, countless fine cracks spread all over the surface. Since the chrome-plated film has a high internal stress, cracks occur in the chrome-plated film due to the movement of releasing the stress. This crack has a width of 0.
When it is 01 to 0.03 μm, it spreads like a shell over the entire surface and becomes the crack.

During printing, the surface of the roller comes into contact with the paper roll and the undried ink printed on the paper roll, so the ink soaks into the cracks, and paper dust also mixes in to become stains. Therefore, when the roll of paper comes into contact with the surface of the roller, the roll of paper becomes dirty.

Therefore, in order to prevent stains,
It is necessary to form the plating film with a material that does not cause cracks. For example, as a plated film that does not cause cracks, it is possible to use a nickel plated film having an internal stress lower than that of the chromium plated film. Nickel plating has no cracks and, because it has no cracks, has better corrosion resistance than chromium plating. However, plating with nickel alone is inferior in hardness and wear resistance.

Therefore, in the present invention, a nickel alloy plating coating is formed on the surface of the roller. When nickel is mixed with other metal elements such as molybdenum, the crystal structure is changed, and the wear resistance, hardness, and corrosion resistance are improved. Therefore, when printing is performed using a roller having a nickel-based alloy coating on its surface, the roller surface has no cracks, and dirt is less likely to adhere to the roller. Also, even if it adheres,
Since it does not soak into the interior, it can be easily removed.

〔Example〕

Hereinafter, features of the present invention will be specifically described based on embodiments with reference to the drawings.

FIG. 1 is a schematic view of an embodiment of a color printing machine using a roller for a printing machine of the present invention.

The color printing machine includes a rotary printing unit 2 for black printing and a rotary printing unit 3 for color printing, which are provided adjacent to each other on a machine bed 1, and a paper feeding device for supplying a web P to the rotary printing units 2 and 3. 4 and. A paper roll 5 is attached to the paper feeding device 4.

The blank paper P pulled out from the paper roll 5 is guided to the rotary printing unit 2 for black printing through a plurality of guide rollers 6a, 6a. The rotary rotary printing unit 2 for black ink printing is provided with two sets of plate cylinders 7 and 8 and blanket cylinders 9 and 10, and the web P passes between the pair of blanket cylinders 9 and 10 so that one side, for example, the back side, Printed with black ink. In addition,
When performing color printing by using the rotary printing unit 2 for black printing and the rotary printing unit 3 for color printing, only one plate cylinder 7 and blanket cylinder 9 are used, and the other plate cylinder 8 and blanket cylinder 10 are used. Is used as a dummy.

The web P ₁ after the back surface printing is guided to the printing section of the rotary printing unit 3 for color printing through a plurality of guide rollers 6b to 6m. In the rotary printing unit 3 for color printing, four sets of plate cylinders 12 to 15 and blanket cylinders 16 to 19 are provided for the common impression cylinder 11, and the common impression cylinder 11 and each blanket cylinder 16 to 19 are provided.
The paper P ₁ is sequentially passed between the _first and second sides, and the other surface, for example, the front surface, is sequentially printed with yellow, magenta, cyan, and black inks.

Therefore, from the rotary printing unit 3 for color printing, the web P ₂ whose back surface is printed in black and whose front surface is printed in four colors is obtained. The paper roll P ₂ after double-sided printing is
It is sent to a folding machine (not shown) via n, 6p to 6s.

In the above color printer, the web moves at a high speed of about 8 to 10 m / s, so that the black ink printed on the back side of the rotary printing unit for black printing 2 passes through the guides 6b to 6m before it is dried. To the common impression cylinder 11 of the rotary printing unit 3 for color printing. At this time, since the guides 6b, 6e, 6i, 6k come into contact with the printing surface of the paper web P ₁ , there is a risk that the surface of the guides will become dirty. Therefore, at least one of these guide guides 6b, 6e, 6i, 6k is provided with a nickel-based alloy on the surface of the guide guide 6b located in the paper conveyance path immediately after being printed by the blanket cylinder 9 of the rotary printing unit 2 for black printing. Form a gold plated coating. In this embodiment, the guides 6b, 6i, 6k
A nickel-based alloy plating film is formed on. Further, as will be described later, a nickel-based alloy plating film is also formed on the guide guide 6c for the case where simultaneous double-sided printing is performed by the rotary printing unit for black printing.

FIG. 2 shows the structure of each of the above guides as a representative of the guide roller 20. The surface of a core 21 made of steel such as S45C, STKM16 is 0.2 to 0.3 mm thick, for example 0.3 mm thick, and is nickel-based. An alloy plating film 22 is formed. This coating 22
Is a nickel-based alloyed plating film,
Available metal elements include molybdenum, tungsten, cobalt, phosphorus, boron and iron.

The composition ratio in the nickel alloy plating film changes due to various factors, but basically because the internal stress of the plating film is related to the occurrence of cracks, excessive mixing causes the occurrence of cracks, so it is a good idea. Absent. However, in order to secure the same hardness and wear resistance as those of the conventional chromium plating, the composition ratio of the coating film according to these characteristics is required.

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 3-40% 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, phosphorus is 5 in nickel.
Plating film containing ~ 15% by weight.

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

In nickel-iron alloy plating, iron is 5-25 in nickel.
Plating film containing wt%.

By using the nickel-based alloy plating film,
It is possible to reduce the internal stress of the plating film while maintaining high hardness and wear resistance. Therefore, a clock is not generated in the plating film, and dirt due to ink and paper dust is less likely to adhere to the surface of the guide roller 20.

Therefore, by transporting the paper roll using the guide roller 20 having the nickel-based alloy plating film 22 formed thereon, dirt is unlikely to adhere to the paper roll.

The common impression cylinder 11 of the rotary printing unit 3 for color printing is also
Since the printed surface of the paper roll P ₁ comes into contact, the surface may be soiled. Therefore, as with the guide roller, a nickel alloy plating film is formed on the surface of the common impression cylinder 11.

FIG. 3 shows the structure of the common impression cylinder 11, in which a nickel-based alloy plating film 32 is formed on the surface of a core 31 made of steel. The coating 32 is a nickel-based alloyed coating 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 P ₁ in contact with the common impression cylinder 11 is less likely to become dirty.

In addition, the guide rollers 6n, 6p ~ 6s located after the common impression cylinder 11
Since it comes into contact with either the front side or the back side of the printing surface, a nickel-based alloy plating film may be formed on these guide rollers to prevent contamination.

As described above, by forming the nickel-based alloy nickel coatings 22 and 32 on the surfaces of the guide roller 20 and the common impression cylinder 11 that rotate in contact with the printing surface of the paper roll, dirt is unlikely to adhere to these surfaces. Become. Therefore, the interval for cleaning the roller can be lengthened. In addition, since the nickel-based alloy plating is superior in corrosion resistance to the chromium plating, the life of the roller itself is extended.

According to the operation results, when the nickel-based alloy plating film was formed on the surfaces of the guide rollers 6b, 6c, 6i, 6k and the common impression cylinder 11 among the guide rollers shown in FIG. There is no need for cleaning even after printing 1 million to 5 million copies. On the other hand, in the case of the conventional guide roller and common impression cylinder with the chrome-plated coating,
Cleaning was required every 150,000 copies.

In the above-described embodiment, the case of color printing has been described as an example, but it is also possible to perform normal black printing using the above-mentioned printing machine.

In this case, by operating both of the two sets of the plate cylinders 7 and 8 and the blanket cylinders 9 and 10 in the rotary printing unit 2 for black-and-white printing, when the web passes between the pair of blanket cylinders 9 and 10, both sides Is printed with black ink at the same time. In this case, the guide roller 6c also comes into contact with the printing surface, so that the guide roller 6c is also formed with a chrome plating film. Therefore, the stains on the guide roller are less likely to adhere even when printing is performed in a single black color, and the stain-free printing can be performed. The roll paper, both sides of which have been printed by the rotary printing unit for black printing 2, is directly sent to the folding machine without passing through the rotary printing unit for color printing 3.

〔The invention's effect〕

As described above, according to the present invention, since the 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 sheet passes while making contact, high hardness and It is possible to prevent the occurrence of cracks while maintaining wear resistance. Therefore, dirt does not easily adhere to the surface of the roller, and the paper does not become dirty due to the dirt of the roller. In particular, in the case of color printing, stains on the paper significantly reduce the print quality. Therefore, by preventing this stain, high quality color printing can be performed. Further, the corrosion resistance is improved as compared with the conventional chromium plating. Further, since the rollers are less likely to be soiled, the number of times of cleaning the rollers can be reduced, the stagnation time of the printing work due to the cleaning work can be shortened, and the work efficiency can be improved. Also, since the frequency of cleaning work is reduced,
It is possible to cope with a large amount of printing without introducing an expensive automatic cleaning device.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of a printing machine of the present invention, FIG. 2 (a) is a perspective view of a guide roller used in the printing machine, and FIG. 2 (b) is a sectional view of the guide roller. 3 (a) is a perspective view of a common impression cylinder used in the printing machine shown in FIG. 1, and FIG. 3 (b) is a sectional view of the 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 to 6s, 20: Guide rollers 7, 8: Plate cylinder 9, 10,16～19: blanket cylinder 11: the common impression cylinder, 12-15: plate cylinder 21, 31: core 22, 32: nickel alloy plating film P, P _1, P _2: the web

Claims (4)

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