JP3132965B2 - Roller surface antifouling treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling treatment method for a roller surface, and more particularly, to an antifouling method for a roller surface used in easily contaminated places such as a printing machine, a paper machine, a paper machine, and an electrophotographic printing machine. Regarding the processing method.

[0002]

2. Description of the Related Art Conventionally, various devices have been devised as antifouling measures for rollers used in easily contaminated places such as printing machines, paper machines, paper machines, and electrophotographic printing machines. Hereinafter, a roller of a printing machine will be described as an example. FIG. 6 shows the structure of a conventional sheet-fed printing press. In the printing press shown in the figure, the paper conveyed from the paper supply unit 7 passes through a group of rollers composed of a plate cylinder 8, a blanket cylinder 9, and an impression cylinder 10, is printed, and is sent to a paper discharge unit 11. In the case of single-sided printing, the sheet passes through the roller group only once. In the case of double-sided printing, the paper is turned over by a reversing mechanism including a reversing cylinder 12 and a reversing double cylinder 13, and the paper is printed on the back side. Here, the surface of the impression cylinder 10 is brought into contact with the pre-printed fresh-dried ink on the front side, and the blanket cylinder 9 is printed during the reverse side printing.
A printing pressure (approximately 1 kgf / cm ^{2 in} surface pressure) is applied between the ink and the ink, so that the ink adheres and is contaminated. Although there is no problem with the initial contamination, the amount of ink deposited increases after a long operation, and the ink is transferred back to the paper surface, which results in soiling the printing paper surface. As a countermeasure, a method of periodically cleaning the surface of the impression cylinder 10 with a cleaning liquid (organic solvent such as kerosene, acetone, etc.) has been adopted. There is a strong need for a difficult impression cylinder surface. The material of the surface of the impression cylinder 10 is generally chrome plating from the viewpoint of durability against paper rubbing and corrosion resistance.

FIG. 9 is a schematic diagram of a newspaper printing machine. While the sheet-fed printing press prints on sheets (cut sheets), a newspaper printing press prints on continuous paper. In order to control the tension applied to the paper at this time, several guide rollers 19 are arranged between the printing units 18 to apply tension to the paper. At this time, the printing surface directly hits the guide roller surface, as in the case of the sheet-fed printing press, so that the printing surface is stained with ink and print quality is deteriorated. Various surface treatment methods are being studied for such a contamination problem, and specific examples of the impression cylinder are shown in FIGS.

First, a competitor's product A is an FCD as shown in FIG.
A chromium plating layer 3 having a thickness of about 10 μm is formed on a substrate 4 made of (spheroidal graphite cast iron), and then blasting is performed to make the surface uneven. With this product, the hard chrome layer is blasted, so the uneven steps are not so deep and 3 ~
The range is 5 μm. FIG. 5 shows the stain resistance (resistance to ink adhesion, indicated by the amount of ink adhesion in the figure) and ink removability (easiness of removal of the adhered ink) to the ink on the surface of the impression cylinder. The surface of this product is smooth to some extent, so the ink has excellent removability.However, because of the smoothness, the contact area with the ink on the paper is large, so the stain resistance is small and the amount of ink adhered is large. I have.

On the other hand, the competitor's product B is based on the completely opposite reforming idea of the competitor's product A, and has a large surface roughness as shown in FIG. As a manufacturing method, a blast treatment is directly performed on the base material 6 of the same FCD as that of A, and then a chromium plating layer 5 is formed for the purpose of improving corrosion resistance and wear resistance. Competitor A
Unlike blasting to a chromium layer as described above, the surface unevenness is large because it is applied to cast iron. The plating film is FCD
It is formed according to the surface unevenness profile. Competitor B
The unevenness in step (2) is 25 to 30 μm, which is considerably larger than that of the competitor A. However, since the contact with the ink is performed at a small area at the tip of the convex portion, the stain resistance is improved as shown in FIG. However, even a slight amount of the ink is gradually buried in the concave portion and becomes difficult to remove due to the printing pressure and the fluidity of the ink. The stain resistance and ink removal property data shown in FIG. 5 are based on the results of element tests under the conditions shown in Table 1.

[0006]

[Table 1] (The nip condition means the pressure (surface pressure) applied between the printing paper and the roller)

[0007]

SUMMARY OF THE INVENTION In view of the state of the prior art, the present invention modifies the surface of a roller used in a contaminated area such as a printing machine, a paper machine, a paper machine, an electrophotographic printer, or the like. Another object of the present invention is to provide an antifouling treatment method for a roller surface having a surface structure in which the amount of dirt due to an adhering substance is small and the adhering substance can be easily removed by means such as cleaning.

[0008]

According to the present invention, there is provided (1) a method in which a step between a concave portion and a convex portion is formed on a roller surface with a step of 20 to 30 .mu.m, and then a step between the concave portion and the convex portion is 5 to 15 .mu.m. (2) The method of (1), wherein the roller is a roller for a printing press, wherein the roller is a roller for a printing press. The above-mentioned (1) or (2), wherein the resin is a resin having a surface energy of 40 dyne / cm or less, and (4) the resin is a fluororesin, a silicone resin, a polyester resin, or a polyacetal resin. (1) to (3), which are resins selected from the group consisting of phenolic resins, polyamide resins, polyimide resins and aromatic polyamide resins, or copolymers thereof.
Any one of the roller surface antifouling treatment methods.

In the present invention, as shown in FIG. 1, a coating layer of a resin 1 is provided in a concave portion of a concave and convex portion of a surface material 2 on a roller surface and a sealing process is performed. Is 5 to 15 μm. The material of the surface material 2 may be a material used for a conventional roller, such as a material such as FCD (spheroidal graphite cast iron) or a substrate made of a composite material such as fiber reinforced plastic plated with chromium.

When surface treatment is performed by the method of the present invention,
First, unevenness having a step of 20 to 30 μm is formed on the surface material. There is no particular limitation on the method of forming the irregularities.
It is preferable to use a method in which irregularities are formed on the surface of a substrate such as D by sandblasting or the like, and then the surface is strengthened by chrome plating or the like. A resin coating layer is formed by dissolving or dispersing in a solvent on a surface material having a surface having irregularities in this way, or by applying a method of spraying or impregnating a molten and liquefied resin and then solidifying the resin. It is formed and a sealing process is performed.

The resin used for the sealing treatment is 40 d
It is preferable that the resin has a surface energy of yne / cm or less. In the case of a resin having a surface energy of more than 40 dyne / cm, the effect of non-adhesion on the adhered substance is small, and the stain resistance and stain removal properties are close to those of conventional untreated products.
The effect of the modification is small. The surface energy of the base metal is about 50 to 60 dyne / cm. Specific examples of the resin used include a resin selected from the group consisting of a fluorine resin, a silicone resin, a polyester resin, a polyacetal resin, a phenol resin, a polyamide resin, a polyimide resin, and an aromatic polyamide resin, or a copolymer thereof. Can be.

[0012]

FIG. 2 shows the characteristics of the surface of the impression cylinder of the printing press roller manufactured by the method of the present invention. The data in FIG. 2 was measured by providing a coating layer of polytetrafluoroethylene (surface energy: 17 dyne / cm) in a concave portion of a substrate made of FCD (25 μm in unevenness). For comparison with the prior art, the characteristic curves of the competitor products A and B (without sealing treatment) are also indicated by dotted lines. First, regarding the ink stain resistance, the stain resistance curve shifts upward in a portion having a step of 15 μm or less by providing a resin coating layer on the concave portion of the roller surface as in the present invention, and the stain resistance is improved. You can see that there is. That is, it is more effective to improve the ink stainability by performing the sealing treatment with the resin even at the same uneven steps. It is considered that this is because the surface energy of the resin is lower than that of the metal of the surface material, and the adhesion of the ink is smaller. If the step exceeds 15 μm, the resin surface of the concave part will be on the lower side, and the ink on the paper under the nip may not be able to reach the bottom enough. Had a limit and was at the same level as the competitor B according to the prior art.

Next, regarding the ink removability, the curve shifts upward in a portion where the unevenness is 20 μm or less.
As in the case of the above-described stain resistance, it can be seen that the product of the present invention in which the resin is encapsulated has the same ink removal property even with the same step. Also, in this case, as in the case of the above-described stain resistance, the level difference is 20%.
If it exceeds μm, no difference was observed depending on the presence or absence of resin encapsulation.

When the ink stain resistance and the ink removal property are comprehensively evaluated as described above, the conventional uneven step is 3 to 5 μm.
And those with emphasis on ink removal, 25-30
The surface roughness of μm and the focus on the improvement of the adhesion are insufficient in the overall stain resistance, but the resin is encapsulated in the concave portion by the method of the present invention, and the unevenness (the top of the convex portion) is obtained. It can be seen that by setting the difference between the height and the height of the concave portion and the surface of the resin layer within a range of 5 to 15 μm, a surface property effective for both ink stain resistance and removability can be obtained.

Further, unlike the conventional metal roller, since the surface is processed with resin, there is a concern that the resin may be worn due to rubbing with the paper at the nip during printing. However, the durability of the coating film shown in FIG. As is clear from the curve showing the above, if the unevenness step is 5 μm or more, it is possible to sufficiently prevent the resin damage of the concave portion, and it can be seen that there is a reinforcing effect as a base material matrix. That is, the mechanical sliding (rubbing) force that causes the wear of the resin is received by the base material, thereby preventing the resin from being damaged. The durability of the coating film is about 1000
The residual area ratio of the resin per predetermined area of the roller surface after operation for one year (one year) was evaluated by a value measured by a stereoscopic microscope (100 times) (100% when no resin was dropped).

[0016]

EXAMPLES The method of the present invention will be described more specifically with reference to the following examples. (Example 1) An example in which the method of the present invention is applied to an impression cylinder of a sheet-fed printing press will be described. FIG. 7 shows a schematic shape of the impression cylinder, and 14 is a surface treatment unit. FIG. 8 is a cross-sectional view of the roller after surface treatment by the method of the present invention. The production of this impression cylinder was performed as follows. That is, the base material 15 (FC
D) was blasted (sprayed with an alumina abrasive having a particle size of 20 μmφ or less for 5 minutes) to form unevenness with a step of 20 to 30 μm, and then a 5 μm thick chromium plating layer 16 was formed by electrolytic plating. The substrate was strengthened. Then P
FA (tetrafluoroethylene / hexafluoropropylene copolymer resin, surface energy 25 dyne / cm) 17 was coated and baked in six separate steps, and overflow coating was performed until the chromium plating layer was completely hidden. Thereafter, the surface was polished with a sandpaper of 2000th count. As a result, the wear of the resin was faster than that of the chromium of the surface material (it was removed so as to be removed), and unevenness having a step of 10 μm was formed on the surface. The impression cylinder manufactured in this way is different from the conventional one in which only the surface roughness (steps of unevenness) is changed,
A step is set in a predetermined range, and a sealing process with a resin is performed.

The impression cylinder produced as described above was tested for stain resistance and ink removability. The results are as shown in Table 2, which shows that both the stain resistance and the ink removal property are superior to those of the conventional product, and that the method of the present invention is effective as a measure against ink stain as a whole. Also, PF
Substantially the same effect was obtained by using polyorganosiloxane, polyester resin, polyacetal resin, phenol resin, nylon 6, nylon 66, polyimide resin and aromatic polyamide resin instead of A. In addition,
The evaluation criteria are as shown in Table 3.

[0018]

[Table 2]

[0019]

[Table 3]

(Embodiment 2) An example in which the method of the present invention is applied to a guide roller for a newspaper printing machine will be described. FIG. 9 is a schematic diagram of a newspaper rotary press. Paper is printed by a printing unit 18 and sent to a paper discharging unit 20 while being transported between guide rollers 19. Because the guide roller comes in contact with freshly dried ink immediately after printing,
As in the case of the impression cylinder of the sheet-fed printing press, there is a problem of contamination with ink, which is dealt with by periodic cleaning. FIG. 10 is a cross-sectional view of the guide roller after surface treatment by the method of the present invention. In general, the guide roller is lightened in order to prevent irregularities in cutting and misalignment at the time of startup, but the base material of the roller in this example uses light CFRP (ceramic fiber reinforced plastic). In this example, an unsaturated polyester resin (46% fiber content) reinforced with SiC whiskers (average diameter 0.2 μm, aspect ratio 5 to 10) was used.

When a bundle of fibers (whiskers) 21 is wound around the core material while intersecting with each other, the surface becomes regularly uneven as shown in FIG. Since chromium plating cannot be performed due to poor electrical conductivity as it is, a zinc layer 22 having a thickness of 1 μm is formed by electroless plating as an intermediate layer, and a chromium plating layer 23 for imparting wear resistance and corrosion resistance is formed thereon. It was formed with a thickness of 2-3 μm. Then, a resin layer 2 was formed using polytetrafluoroethylene in the same manner as in Example 1.
4 was formed and sealed to form a guide roller having an uneven step of 5 μm. FIG. 11 is a cross-sectional view showing the vicinity of the surface of an example of a conventional guide roller. In this example, a fluororesin sheet 26 is wound around a CFRP base material 25 to reduce ink stains. This surface is almost smooth.

The obtained roller had the same excellent ink stain resistance as that obtained in Example 1. Further, as shown in FIG. 12, in the conventional fluororesin sheet winding type, the resin wears out as the operation time elapses, and it is necessary to replace the resin at an early stage. Since it is held by a chromium plating layer having a good quality, it has excellent durability and can maintain high stain resistance performance for a long period of time.

[0023]

According to the method of the present invention, the surface of a roller used in a printing machine, a papermaking machine, a paper machine, an electrophotographic printing machine, or the like which is easily contaminated is modified so that dirt due to adhered substances is reduced. Further, even if the adhered substance adheres, it can be easily removed by means such as cleaning, and a roller which can be easily maintained and managed can be manufactured. Further, if the details of the effects of the present invention are specifically noted for an example of a printing machine,
It is as follows. (1) The frequency of the regular cleaning of the roller surface, which has been conventionally performed, has been reduced, and the cost per printed material has been reduced by saving the cleaning liquid, reducing the number of cleaning workers, and improving the operation rate. (2) The problem that the stained ink accumulated on the roller, which has conventionally occurred, is reversely transferred to the printed matter and stains the paper surface is solved.
Printing quality can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the surface structure of a roller modified by the method of the present invention.

FIG. 2 is an explanatory diagram showing characteristics of the surface of an impression cylinder of a printing press roller manufactured by the method of the present invention.

FIG. 3 is a cross-sectional view showing an example of the surface structure of a roller according to the related art.

FIG. 4 is a cross-sectional view showing another example of the surface structure of a roller according to the related art.

FIG. 5 is an explanatory view showing the stain resistance and ink removability of ink on the impression cylinder surface of a printing press roller according to the related art.

FIG. 6 is a schematic sectional view showing the structure of a normal sheet-fed printing press.

FIG. 7 is an explanatory view showing a schematic shape of an impression cylinder in the printing press.

FIG. 8 is a cross-sectional view illustrating a surface structure of a roller after a modification process according to the first embodiment.

FIG. 9 is a schematic diagram of a newspaper printing machine.

FIG. 10 is a cross-sectional view illustrating a surface structure of a roller after a modification process according to the second embodiment.

FIG. 11 is a cross-sectional view near the surface of an example of a conventional guide roller.

FIG. 12 is a graph showing the relationship between the operation time of the roller of Example 2 and the amount of resin wear.

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Claims (4)

(57) [Claims] 2. The method according to claim 1, wherein the step between the concave portion and the convex portion on the roller surface is 20 to
An antifouling treatment method for a roller surface, characterized in that after forming irregularities of 30 μm, a resin coating layer is provided in the concave portions so that the step between the concave portions and the convex portions of the irregularities is 5 to 15 μm. 2. The method according to claim 1, wherein the roller is a roller for a printing press. 3. The method according to claim 1, wherein the resin has a surface energy of 40 dyne / cm or less. 4. The method according to claim 1, wherein the resin is a fluororesin, a silicone resin,
The antifouling of the roller surface according to any one of claims 1 to 3, wherein the resin is a resin selected from the group consisting of a polyester resin, a polyacetal resin, a phenol resin, a polyamide resin, a polyimide resin, and an aromatic polyamide resin, or a copolymer thereof. Processing method.