JP2011093236A - Inking roller for offset press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller which hardly causes roller stripping and roller scratch, which has high rust-proofing effect and superior heat conductivity, and which is also inexpensive. <P>SOLUTION: The inking roller for an offset press includes a metallic roller 13 and a resin layer 15 on the surface of the metallic roller 13, wherein the resin layer 15 is formed by coating the surface with wear resistant, solvent resistant and chemical resistant resin and is provided with a smooth surface having a surface roughness Rz of 1-15 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inking roller for an offset printing press, and more particularly to an inking roller for an offset printing press excellent in wear resistance, chemical resistance, oleophilicity, water repellency, and solvent resistance.

  In a general offset printing machine, as shown in FIG. 2, the inking device kneads the ink called from the ink fountain to give it an appropriate fluidity and makes it into an appropriate emulsified state by kneading with dampening water. Has the role of supplying the ink to the printing plate. For this purpose, a hard roller (metal roller; copper, rilsan) and a soft roller (rubber roller; NBR) are alternately arranged in several to twenty units.

The surface characteristics of this hard roller are those with particularly good ink transferability (surface energy is higher than the surface energy of the ink, and the energy lipophilic ratio is large), and the lipophilicity does not deteriorate over time. is required. As a material suitable for them, a copper-plated (or copper clad tube inserted) iron roller surface or a roll-lined roller is generally used.

  The main purpose of this inking device is to stably supply the amount of ink corresponding to the pattern area ratio of the plate surface to the plate surface, but due to the characteristics of offset printing technology, dampening water is always supplied to the plate surface. . In the case of waterless planographic printing, water is not used. The dampening water is supplied to the printing plate via a water supply roller (FIG. 2; reference numerals 8 to 11). In addition, a bridge roller ((FIG. 2; reference numeral 12) is disposed between the water supply roller and the inking roller. However, in many cases, the device is designed to form the optimal emulsified state of ink and water in a short time. An etchant containing chemicals to prevent it is added.

The fountain solution supplied to the printing plate is transferred to the printing paper through the blanket cylinder (rubber cylinder) 2. A coating agent (kaolin; SiO ₂ , Al ₂ O ₃ , calcium carbonate; CaCO ₃ etc.) is provided on the surface of printing paper (especially coated paper, art paper) in order to smooth the surface of the paper and increase glossiness. It is coated. In addition, a small amount of calcium phosphate Ca ₃ (PO ₄ ) ₂ is blended in the ink to improve the emulsifying properties of the ink.

  When dampening water is supplied to the printing paper through the blanket cylinder, a part of the coating material on the paper surface dissolves in the water and adheres to the blanket. It flows back to the roller and is kneaded into the emulsified water in the ink on the inking roller.

  Also, by kneading the ink with the inking roller, the temperature of the inking roller (ink) rises, and if it exceeds the appropriate printing temperature (35-40 ° C.), various printing troubles occur. In general, a method of cooling the roller by circulating water on the inner surface of the roller (copper roller) is employed.

First, if a copper plating (or copper clad) roller is used as the hard roller in the inking roller, the new copper surface is oleophilic and water-repellent, but if the operation is continued for a while Oxidation with etchant in dampening water (pH of dampening water is usually adjusted to 4-6), or paper coating materials (CaCO ₃ , SiO ₂ , Al ₂ O ₃ etc.), in ink Of Ca ₃ (PO ₄ ) ₂ adheres to the surface of the copper roller and easily changes to hydrophilicity.

In particular, when it becomes hydrophilic, the water on the printing plate is likely to rise to the inking roller, and the emulsified ink is more likely to adhere to the water than the ink on the surface of the copper roller, so that it is difficult for the ink to transfer to the copper roller surface. . Therefore, it is difficult for the ink called from the ink fountain to descend on the plate surface,
Increasingly, the water on the printing plate flows back onto the inking roller, causing a roller stripping phenomenon (a phenomenon in which ink does not adhere to the ink roller during offset printing).

  Such a roller stripping phenomenon is likely to occur when printing on a non-water-feed printing material such as a film or chemically synthesized paper, and countermeasures are particularly demanded in recent years when high-quality printed materials are required.

On the other hand, when a resin-lined rilsan roller is used as the hard roller, it has better lipophilicity (lower contact angle with soybean oil) and lower water repellency (lower contact angle with water) than copper. However, the oxidation of the surface of the Rilsan roller, the adhesion of paper coating materials (CaCO ₃ , SiO ₂ , Al ₂ O _3, etc.) and Ca ₃ (PO ₄ ) ₂ due to long-term operation is less than that of the copper roller. The oil and water repellency changes little, and when used for a long period of time, the rilsan roller can maintain a better lipophilicity and water repellency than the copper roller. In other words, the Rilsan roller is superior to the copper roller in terms of roller stripping resistance.

  In addition to the above conventional example, Patent Document 1 relates to an inking roller for offset printing that supplies printing ink to a plate cylinder, and at least a surface layer of a synthetic rubber body is made of a metal such as aluminum or brass. A roller technology in which a urethane resin in which powder is uniformly mixed is formed is disclosed.

  Further, Patent Document 2 relates to an ink roller of an offset rotary press, in which an inking roller in which a composite material of copper and ceramics is thermally sprayed on a metal roller surface and the copper content of the sprayed layer is 60% or more. This technique is disclosed. Copper has low Vickers hardness and easily wears when ink is scraped off with a doctor blade, so by applying a sprayed coating of ceramic and copper mixed powder, it maintains wear resistance while maintaining the lipophilicity of copper. It is a technology that aims to improve.

JP-A 61-14997 JP-A-62-167092

  However, in the case of the above Rilsan Roller, Rilsan is a resin and is easily scratched compared to metallic copper, from which a corrosive liquid penetrates and rusts at the interface with the iron base material, and the film swells. Since it is easy to cause troubles, it is necessary to line it up thickly (about 0.4 mm) (if the film is thin, there is a problem such as swell of the film due to tearing and rusting).

  Further, in the case of a cooling roller, a rilsan roller in which a resin having a low thermal conductivity is thickly lined is not suitable for a cooling roller because the cooling efficiency is lowered.

  Furthermore, as a coating method of rilsan resin, a fluid immersion method is generally used in order to efficiently coat a thick film. However, since the coating by the fluidized immersion method has a large variation in the thickness of the coating, it is necessary to coat the coating so as to be considerably thicker than the finished dimensions and to scrape off the surplus by polishing. Therefore, although the coating efficiency is good, there is a problem that the time and cost required for polishing are significantly increased and the manufacturing cost is also increased.

  On the other hand, the invention according to Patent Document 1 aims at improving the ink form roller (rubber roller), and the surface layer of the synthetic rubber roller main body is a roller formed with a urethane resin in which metal components such as aluminum and brass are uniformly mixed. Yes, it prevents the synthetic rubber roller body from deteriorating due to the influence of the solvent contained in the printing ink, and creates fine irregularities on the surface to eliminate the scattering of ink particles. It is not a technology for improving rollers.

  Moreover, in the invention which concerns on patent document 2, since the sprayed coating of copper (60%) and ceramics (chromium carbide) is used as a roller outermost layer, the said sprayed coating is more hydrophilic than copper, Further, copper is oxidized during use and becomes more and more hydrophilic, so that it is not preferable from the viewpoint of roller stripping as an ink kneading roller combining a large number of hard rollers and soft rollers (rubber rollers). Further, the ceramic sprayed layer as described in Reference 2 is usually porous, and unless special treatment is performed, corrosive fountain solution penetrates into the pores of the sprayed coating, resulting in corrosion at the interface with the metal roller. There is a problem of blistering of the sprayed coating.

  In order to eliminate these drawbacks and problems, an object is to provide a roller that is less likely to cause roller stripping, less likely to cause scratches on the roller, has a high rust prevention effect, good thermal conductivity, and is inexpensive. .

  In order to achieve the above objects, a smooth surface having a surface roughness Rz of 1 to 15 μm formed by coating a metal roller and a resin having abrasion resistance, solvent resistance and chemical resistance on the surface of the metal roller. An inking roller for an offset printing machine, comprising a resin layer having a smooth surface. And a method for manufacturing the same.

The inking roller for an offset printing machine according to the present invention is excellent in resistance to roller stripping as compared with a conventionally known copper plating roller, and is further better than a known rilsan roller.
Compared to the conventional method of thickening rilsan on the iron base and finishing the diameter accuracy and roughness by polishing, there is also a cost reduction effect by eliminating the polishing process after resin coating, which is very practical. It is a highly characteristic invention.

Further, the invention has an effect that the cooling efficiency of the roller is high because the resin layer having a lower thermal conductivity is thinner than the conventional thick film lil sun lining roller.

  Furthermore, the inking roller for an offset printing press according to the present invention is less likely to deposit calcium fixed matter on the roller surface, and has excellent cleaning properties for calcium solid matter.

The figure which shows typically the cross-section in one embodiment of the ink kneading roller (hard roller) which concerns on this invention, The figure which shows an example of the ink and water supply roller arrangement | sequence in an offset printing machine, Roller surface roughness chart of Example 1 10 is a roughness chart of the roller surface of Reference Example 2.

  The first aspect of the present invention is a concavo-convex structure having a thickness of 100 to 250 μm and a surface roughness Rz of 30 to 60 μm formed by densely spraying a metal roller and a metal material having corrosion resistance and wear resistance on the surface of the metal roller. A resin layer having a smooth surface with a thickness of 20 to 150 μm and a surface roughness Rz of 1 to 15 μm provided on the surface of the metal layer by an electrostatic coating method, and the resin layer is An inking roller for an offset printing press having a contact angle with soybean oil of 30 ° or less and a contact angle with water of 80 ° or more.

  Since a wear-resistant and corrosion-resistant metal layer is provided between the metallic roller and the resin layer by dense thermal spraying, the resin layer can be efficiently coated with a thin film coating by an electrostatic coating method. In addition, high corrosion resistance can be maintained. In addition, since the resin layer is hard to be damaged deeper than the convex portion of the metal layer, the life of the resin film can be extended. Furthermore, the ink cooling efficiency as a cooling roller can be improved by thinning the resin layer having low thermal conductivity.

  FIG. 1 shows a schematic diagram of the structure of the inking roller according to the present invention. That is, FIG. 1A shows that after a metal (sprayed) layer 14 is formed on the surface of a metal roller (base material) 13, a wear-resistant, solvent-resistant, and chemical-resistant resin 15 is applied to the metal (sprayed). ) Formed on the surface of the layer 14.

  The thermal spraying according to the present invention is preferably dense thermal spraying, and any thermal spraying method such as plasma thermal spraying, flame thermal spraying, arc thermal spraying or the like may be used as the thermal spraying method for performing dense thermal spraying. In order to increase the density, it is necessary to form a dense film close to pores, and it is preferable to perform spraying using a spray gun such as HVOF, HVAF, or HVCW (wire material spray high-speed flame gun). Also, depending on the method of the spray gun, the spray material can be selected from powder and wire suitable for the spray gun.

  Since the above-mentioned dense thermal spraying is expensive in terms of cost, it is possible to reduce the film thickness of the thermal spray coating by making the pores of the thermal spray coating non-porous by sealing a highly permeable sealing agent, A cheaper spraying method such as plasma spraying may be employed.

  As the above-mentioned sealing agent, any known one that is optimal for the metal material to be used can be used. Specific examples include inorganic silicates such as sodium silicate, alkyl silicate, and organosiloxane, and organic types include epoxy resins, phenol resins, vinyl resins, and butyral resins.

  For example, in order to perform the above-described dense spraying using an HVOF spray gun, a metal material having an average particle diameter of 20 to 35 μm such as SUS316L is used with propylene pressure of 0.5 to 0.8 MPa and a combustion-supporting gas. It is preferable that thermal spraying is performed on a metal roller under the conditions of a certain oxygen pressure of 0.5 to 1.05 MPa, an air pressure of 0.3 to 0.7 MPa, and a spraying distance of 200 to 400 mm.

  Under the above conditions, a metal spray layer having a porosity of 0.1 to 0.5% can be formed by densely spraying a metal material onto a metal roller.

  The surface unevenness formed by spraying a metal material on the surface of the metal roller according to the present invention is intended to increase the adhesion of the resin material to be coated thereon, and the resin material below the convex surface of the metal spray coating is not worn. The purpose is to do so. When the height of the surface irregularities is expressed by roughness, Rz20 to 60 μm is preferable, Rz30 to 60 μm is more preferable, and Rz30 to 50 μm is more preferable. When Rz is less than 20 μm, the effect of preventing the wear of the resin material is lowered, and when Rz is more than 60 μm, the porosity of the coating is increased and the rust prevention effect is lowered, which is not preferable. The surface roughness Rmax and Rz are defined in JIS standard B0601-1982.

  100-250 micrometers is preferable, as for the film thickness of the sprayed coating of the metal layer concerning this invention, 120-230 micrometers is more preferable, and 150-200 micrometers is more preferable. This is because if the film thickness is less than 100 μm, the antirust effect is insufficient, and if it exceeds 250 μm, the cost increases.

  The metal material having high wear resistance and corrosion resistance for thermal spraying according to the present invention is not particularly limited as long as it is a known wear resistance and corrosion resistance metal material. For example, stainless steel, Ni—Cr, Ni—Al, other Ni A base alloy, an Al base alloy or the like is preferable, and can be selected in consideration of the corrosion resistance and cost. Stainless steel is superior in terms of cost, and Ni-based alloys, particularly SUS316L and 80Ni20Cr, are superior in terms of corrosion resistance, and any of the above is suitable by adjusting the thickness of the sprayed film.

  The material of the corrosion-resistant metal roller according to the present invention is preferably a material of various metals such as iron, stainless steel, aluminum, nickel, chromium, etc., and the base material of the corrosion-resistant metal roller according to the present invention has a defect that it is easily rusted. However, an iron pipe that is strong and very inexpensive is more preferable.

  As a resin material of the resin layer according to the present invention, it is necessary to satisfy all the conditions of high lipophilicity, water repellency, abrasion resistance, solvent resistance, and chemical resistance, and the resin layer according to the present invention is lipophilic. As a condition, the contact angle with soybean oil is 50 ° or less, preferably 30 ° or less, and more preferably less than 28 °.

  The “soybean oil” actually used in the present specification is Soybean Oil manufactured by Wako Pure Chemical Industries, Ltd., and uses a saponification value of 188 to 195 and an iodine value of 123 to 42.

  In general, the contact angle between the copper roller and soybean oil when the copper roller is new is 40 to 50 °, so that sufficient ink transfer can be secured, but a material having higher lipophilicity is preferred.

  The contact angle between the conventional rilsan (11-nylon) roller and soybean oil is 28 °, which is much better than copper. By making the material more lipophilic (smaller contact angle with soybean oil) than this, further improvement of ink transfer property is aimed at.

  The condition that the resin layer according to the present invention is water-repellent is that the contact angle with water is 80 ° or more, preferably 83 ° or more, more preferably 85 ° or more. Higher water repellency is better than this. The contact angle with water of the Rilsan roller is 83 ° and the contact angle with water of the rubber roller (NBR) is 80 °. If the contact angle is 80 ° or more, there is no problem. Backflow of water can be suppressed and excessive emulsification of ink can be suppressed. Therefore, by selecting a material having as high a water repellency as possible (a large contact angle with water), the effect of preventing roller stripping is improved.

  In addition, the measuring method of the contact angle in this specification applied JIS R3257 (1999) "wetting test method of substrate glass surface" correspondingly. That is, as shown in the following formula (1), in measuring the contact angle of water or soybean oil, 1.5 to 2 ml of a liquid droplet is dropped on the surface of a horizontally installed equivalent roller, and perpendicular to the body length direction. The digital microscope (Keyence Digital Microscope VH-6300) was adjusted to a magnification of 20 to 50 times so that the droplets could be seen horizontally from the direction of, and the tangent method θ / 2 method ( The contact angle was calculated from the width and height of the droplet at θ: contact angle.

The above hydrophilic numerical value is a contact angle with water when the roller is new, but more importantly, this state does not deteriorate the performance even when used for a long time. In the case of a general copper roller, the initial water repellency (contact angle with water) is very good at 93 to 99 °, but copper is always in contact with acidic (PH; 4 to 6) dampening water. In addition, paper coating materials (CaCO ₃ , SiO ₂ , Al ₂ O _3, etc.) dissolved in dampening water and Ca ₃ (PO ₄ ) ₂ in the ink are easily attached and removed. Since it is difficult, the water-repellent performance is lowered (the contact angle with water is lowered) in a short period.

When the roller surface becomes hydrophilic, the water on the plate surface gradually flows back to the inking roller side, and the water in the emulsified ink easily gets wet on the roller surface, so that the roller surface is oxidized and coated (CaCO ₃ , SiO ₂ , Al ₂ O ₃ ) and Ca ₃ (PO ₄ ) ₂ adhesion in the ink is promoted.

Therefore, it is extremely important to select a material that is difficult to adhere, such as oxidation with dampening water, coating materials (CaCO ₃ , SiO ₂ , Al ₂ O _3, etc.) and Ca ₃ (PO ₄ ) _{2 in} ink. . In this regard, the rilsan roller is preferable to the copper roller, but it is more resistant to oil by using a material that has better lipophilicity (small contact angle with soybean oil) and high water repellency (large contact angle with water). We pursued materials that can improve roller stripping and ink transfer properties.

  The material can be used practically only if it is provided with the above-described lipophilic and water-repellent performances, and further has high wear resistance, solvent resistance and chemical resistance, and is inexpensive and easy to work.

  “Abrasion resistance” used in this specification is a phenomenon in which the surface of the hard roller is damaged by fine solids such as pigments in ink due to the frictional action caused by contact rotation (different speed) between the soft roller and the hard roller. As used herein, “solvent resistance” generally means that polar resins have a large water absorption rate, and if they contain water or a solvent, they cause a decrease in strength, a decrease in transparency, expansion, etc. Absorbance is low with respect to typical solvents used in the vicinity (washing oil, toluene, blanket detergent, UV roller cleaner, water supply roller cleaner, etc.), or the strength does not decrease even if a solvent is included, or expansion The “chemical resistance” used in the present specification refers to a property that is not easily altered to salts, acids, or alkalis.

  While having the above-mentioned lipophilic and water-repellent performance, the resin further having abrasion resistance, solvent resistance, and chemical resistance, that is, the resin according to the present invention is preferably a polyamide resin. As the polyamide resin, for example, The following are listed.

  The resin according to the present invention is preferably a polyamide resin, and the polyamide resin is a polyamide resin mainly composed of amino acids, lactams or diamines and dicarboxylic acids. Examples of the polyamide resin used in the present invention include nylon 6, nylon 12, and nylon 11, and two or more kinds of polyamide resins are used for the purpose of improving the heat resistance and vibration weldability of these polyamide resins. It is also practically preferable to use it as a mixture.

  The present inventor has repeatedly investigated and tested a material having the above-described comprehensive characteristics among many coating materials, and found that 12-nylon is extremely excellent.

  In the inking roller according to the present invention, the thickness of the resin layer when the resin layer is provided on the metal layer formed on the surface of the metal roller is 20 to 200 μm, more preferably 50 to 150 μm, and more preferably 50 to 100 μm. Further preferred. If the thickness is less than 20 μm, the life due to wear is shortened, and if it exceeds 200 μm, if the coating is left as it is, the variation in the diameter accuracy of the roller becomes large, and a polishing step for obtaining the diameter accuracy is required, resulting in an increase in cost. In addition, the thicker the resin layer, the greater the heat transfer resistance, the lower the performance as a cooling roller, and the greater the depth of the scratch (in the case of this patent, the scratch is stopped at the convex portion of the metal sprayed layer). . That is, even if the resin layer is thickened, if a deep flaw is introduced, the roller needs to be replaced. As a result, the life extension effect is low.

  In the inking roller according to the present invention, as a method of providing the resin layer on the metal layer formed on the surface of the metal roller, the resin layer is formed by electrostatic coating. It can be used in powder coating, fluid immersion method, electrodeposition coating method, or flame spraying method to coat the layer.

  By coating the resin layer with the electrostatic coating, it is possible to form extremely smooth unevenness with a very high diameter accuracy and a surface roughness profile different from that of the polished surface. That is, in the case of such a smooth surface roughness profile, it can be controlled within a range of a diameter accuracy of ± 0.1 mm without polishing or SF polishing described later, and Rz is large at around 10 μm, but it is a polished surface. Unlike the plastic, it has a smooth surface due to the melting of the plastic.

  The electrostatic coating method according to the present invention is a method in which a grounded workpiece is a positive electrode, a paint spraying device is a negative electrode, a DC high voltage is applied to create an electrostatic field between both electrodes, and paint fine particles are negatively charged. The method of painting. Moreover, the apparatus used for the electrostatic coating method which concerns on this invention is the powder coating unit EP-MU10-D1 of the corona charge system by Anest Iwata Co., Ltd., and electrostatic coating gun EP-MG10L.

  Thereby, a thin uniform film thickness can be formed on the roller surface, and a roughness profile with a smooth roller surface roughness can be formed by heating and melting. Further, as will be described in the examples described later, the surfaces of the inking rollers according to the first and second aspects of the present invention are undulated (long-period irregularities) as shown in FIG. 3 (the roller surface of Example 1). And roughness (short-period irregularities) generated at a fine pitch. Therefore, the smooth surface of the resin layer of the present invention obtained by the electrostatic coating method is a structure having waviness (long-period unevenness) and roughness (short-period unevenness) generated at a fine pitch, For example, the waviness (long-period irregularities) of the roller surface of Example 1 shown in FIG. 3 has a height of 12 μm with respect to a 2 mm pitch (so-called one wavelength) and is a roughness (short cycle) generated at a fine pitch. This irregularity is a straight correction of the waviness, and the Rmax value is 3 μm high.

  In order to perform the electrostatic coating, for example, a resin having an average particle diameter of 30 to 50 μm is applied to a load voltage of −70 to −75 KV, a discharge pressure of 0.10 to 0.20 MPa, a firing temperature preheating of 150 ° C. to 170 ° C. The coating is preferably performed on a metal roller having a metal layer formed at a melting temperature of 185 to 195 ° C. for 120 minutes and for 20 to 30 minutes.

  The second aspect of the present invention is a metal roller and a thickness of 200 to 300 μm formed by coating the surface of the metal roller with a resin having abrasion resistance, solvent resistance and chemical resistance by a flame spraying method. And a resin layer having a smooth surface with a surface roughness Rz of 1 to 15 μm, and the resin layer has a contact angle with soybean oil of 30 ° or less and a contact angle with water of 80 ° or more. This is an inking roller for an offset printing machine.

When the resin material is coated by electrostatic coating after densely spraying a corrosion-resistant and wear-resistant metal material on the surface of the metal roller like the inking roller shown in the first aspect of the present invention, the final polishing is performed. Although the cost can be reduced by omitting the process, the metal material dense thermal spraying process causes an increase in cost. As a method for avoiding this, a technique of directly thickening and coating resin (12-nylon) on the surface of the second metal roller of the present invention by frame spraying was established.
Corrosion resistance cannot be maintained with only a plastic thin film by electrostatic coating because there is no corrosion-resistant metal spray coating. As a method for uniformly coating the resin (12-nylon) to a thickness of 200 to 300 μm and the film thickness to an average value ± 10 μm, a construction technique by flame spraying was established. As a result, a thick film without pinholes can be formed, and since the surface is uniform and very smooth, it is possible to finish the final product without polishing the resin surface. The cost can be significantly reduced as compared with the inking roller according to the first aspect of the present invention.

  That is, by directly coating the surface of the metal roller with wear-resistant, solvent-resistant, and chemical-resistant resin, after spraying a metal material with corrosion resistance and wear resistance onto the surface of the metal roller, for example, electrostatic coating When compared with a roller coated with a plastic material by the method, an inking roller can be simply manufactured, and an increase in cost for the metal material spraying process can be avoided.

  FIG. 1 shows the structure of the inking roller according to the present invention. That is, B of FIG. 1 is obtained by directly forming the wear resistance, solvent resistance, and chemical resistance resin 15 on the surface of the metal roller (base material) 13.

  In the inking roller according to the present invention, when the resin layer is directly coated on the metal roller, the thickness of the resin layer is 200 to 300 μm, and preferably 220 to 280 μm. Moreover, if the resin layer according to the present invention is thinly formed on the roller surface by frame spraying or the like as described above, the corrosion resistance is insufficient, and if the resin layer is thickened, the cost increases. Therefore, by controlling the thickness of the resin layer in the range of 200 to 300 μm, the film thickness of the 12-nylon coating is less than that of the conventional thick film Rirsan roller (Rilsan thickness; 0.4 to 0.5 mm). Since it is as thin as 2 to 0.3 mm, even when used as a cooling roller, heat conduction is good and cooling efficiency can be improved. If it is less than 200 μm, the life due to wear will be shortened, and there will be a problem of corrosion resistance at the iron roller interface due to resin pinholes. If it exceeds 300 μm, the variation in the diameter accuracy of the roller will increase with coating, and the diameter accuracy will be increased. Polishing process is required, which increases the cost. Furthermore, the thicker the resin layer, the greater the heat transfer resistance and the lower the performance as a cooling roller. Even if the resin layer is thick, if a scratch or a deep scratch occurs, the roller needs to be replaced. As a result, the life extension effect is low. In addition, a thick film with no pinholes can be formed, and a uniform and very smooth surface can be formed, so that the final product can be finished without polishing the plastic surface. Thus, significant cost reduction is possible. Of course, since the final surface is made of plastic (12-nylon) having very high lipophilicity (small contact angle with soybean oil) and high water repellency (large contact angle with water), it is resistant to roller stripping. Is superior to Rilsan Roller as well as copper roller.

  In the flame spraying method, flammable gas such as propane gas and acetylene gas is mixed and burned as a heat source with a combustion-supporting gas such as oxygen, and the combustion flame is used. However, the resin has a low melting point, softening point, and decomposition point. Therefore, a cooling air layer is provided on the outside of the combustion frame in order to suppress heat input without preventing the temperature from rising excessively and to prevent deterioration of the resin. In order to supply the resin according to the present invention from the outside of the cooling air layer and coat the metal roll, in the flame gas spraying method, combustible gas, oxygen, cooling air amount, powder supply amount, spraying distance, spraying Proper control of pitch and spray gun moving speed is important for the formation of a resin spray coating.

  As conditions for the flame gas spraying, for example, a flow rate ratio of a combustible gas such as propane gas and acetylene gas of 4 to 8 L / min and a combustion-supporting gas such as oxygen to the combustible gas is set to 2.7 to 3. 4 is preferably mixed and combusted, the amount of air for cooling is in the range of pressure 0.12 to 0.22 MPa, the powder supply range is 18 to 72 g / min, and the spray distance range is preferably 180 to 300 mm.

  As a result, the film thickness can be uniformly coated within an average value of ± 10 μm. Also, by coating the resin layer by the flame spraying method, it can be controlled within the range of the diameter accuracy ± 0.1 mm without polishing or SF polishing described later, and Rz is large at around 10 μm, but the polished surface is In contrast, the smooth surface resulting from the melting of the plastic has the effect of reducing ink residue when cleaning the roller.

  The overall surface roughness of the resin layer according to the present invention is Rz 1 to 15 μm, preferably 1 to 10 μm, and more preferably 1 to 3 μm. However, with Rz of the surface roughness, the resin layer according to the present invention Since undulations (long-period irregularities) on the surface and roughness (short-period irregularities) occurring at a fine pitch cannot be defined, the undulations (long-period irregularities) and roughness (short-period irregularities) occurring at a fine pitch are not possible. A preferable range independent of the above-mentioned unevenness is preferably one having a height of 15 μm or less and 1.5-2.5 mm pitch waviness (long-period unevenness), and the roughness Rmax obtained by linearly correcting the waviness. (Short periodic unevenness) is preferably 1 to 3 μm.

  If the overall surface roughness Rz of the resin layer is less than 1 μm, the polishing cost is high and impractical, and if the surface roughness Rz of the resin layer is more than 15 μm, the ink cleaning properties are difficult.

  If the waviness of the resin layer exceeds 15 μm, the ink transferability varies.

  Moreover, after coating the resin layer which concerns on this invention on metal roller surfaces, surface roughness may be made into Rz1-15 micrometers by grinding | polishing, 1-10 micrometers is preferable and 1-3 micrometers is more preferable.

  The surface of the resin layer according to the present invention preferably has a surface roughness of Rmax 1 to 3 μm by SF polishing.

  Existing ink kneading rollers (copper plating roller, Rilsan roller) have a roller surface roughness of Rmax 1.6 to 3.2 S by polishing, super-finish polishing (also referred to as SF polishing in this specification), and the like. . When Rmax exceeds 3.2S, the ink on the concave and convex surfaces is difficult to be removed during cleaning of the inking roller, and the cleaning work time is extended, leading to a reduction in work efficiency.

  On the other hand, in the present invention, the resin layer is thinly coated by the electrostatic coating described above, so that the surface accuracy profile is very high and the surface roughness profile is very smooth, unlike the polished surface. In the case of such a smooth surface roughness profile, even when the Rmax value is about 10 μm, there is no problem that the ink on the concave and convex surface of the concave and convex surface is difficult to be removed when cleaning the inking roller. It was found that the roller cleaning performance equivalent to that of the copper-plated roller or rilsan roller can be maintained. That is, it is possible to omit processing steps such as finish polishing for ensuring the diameter accuracy and super-finish polishing for ensuring the surface roughness (Rmax; 1.6 to 3.2 S), thereby enabling a significant cost reduction. .

  SF (super fish) polishing according to the present invention is a Noguchi Koki Co., Ltd. SM-1W-300 × 1300 type cylindrical mirror polishing machine, using a resin grindstone, roll rotation speed, grindstone rotation speed, feed rate. Polishing is performed until the grinding wheel pressure is properly adjusted and the surface roughness reaches the target value.

  Hereinafter, a manufacturing method is demonstrated about an example of the embodiment which concerns on this invention. Needless to say, the scope of the present invention is limited to the following embodiments.

  One embodiment according to the present invention is, for example, stainless steel powder having an average particle diameter of 20 to 35 μm by degreasing and blasting an iron roller base material, followed by a thermal spraying method using a thermal spray gun such as HVOF, HVAF, or HVCW. The metal material is thermally sprayed under predetermined conditions to form a metal layer with a desired thickness. Further, if necessary, the thermal spray coating may be thinned by making it non-porous by sealing a highly permeable sealing agent in the pores of the thermal spray coating. Next, the polyamide resin such as 12-nylon is adjusted in thickness by an electrostatic coating method and coated to obtain an inking roller for an offset printing press. In addition, after coating the polyamide resin, if necessary, it is preferable that the inking roller is produced by lightly polishing and finishing with a water belt sander, SF polishing or the like.

  In another embodiment of the present invention, a metal roller base material is degreased and blasted and preheated at 150 to 250 ° C., more preferably around 200 ° C., and then the resin layer material. A resin layer is formed by coating a lipophilic and water-repellent resin having a predetermined thickness by flame spraying. In order to control the surface waviness after forming a resin layer if necessary, it is preferable to produce an inking roller by lightly polishing, for example, with a water belt sander.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, the scope of the present invention is not limited only to these Examples.
Hereinafter, the present invention will be described more specifically with reference to examples.

1. "Manufacture of inking rollers"
(Reference Example 1)
An iron roller base material was subjected to copper plating with a thickness of 0.2 mm, and the polished copper plating thickness was 0.15 mm and the surface roughness was finished to Rmax; 3.2 S or less. The oleophilicity of the roller surface was a contact angle with soybean oil of 47 °, and the water repellency was a contact angle with water of 94 °. This was subjected to an ink transfer test on a printing press.
(Reference Example 2)
The iron roller base material was subjected to a lilsun lining generally used in the market with a thickness of 0.5 mm, and finished to a lilsan thickness after polishing: 0.4 mm and a surface roughness Rmax: 3.2 S or less. Created a roller. The oleophilicity of the roller surface was a contact angle with soybean oil; 28 °, and the water repellency was a contact angle with water; 83 °.
Example 1
After degreasing and blasting the same iron roller base material as in Reference Examples 1 and 2 above, using a spray gun of a dense spray system (HVOF), the pressure of propylene (0.7 MPa) and a combustion-supporting gas Stainless steel powder (SUS316L) having a particle size range of 10 to 53 μm, which is a corrosion-resistant spray material, was sprayed at a sprayed film thickness of 200 μm under the conditions of a certain oxygen pressure (1.0 MPa), air pressure (0.7 MPa), and spraying distance of 300 mm. The surface roughness at that time was Rmax; 60 μm. Thereafter, a lipophilic / water-repellent plastic (manufactured by Daicel Eponics; VESTOSINT: X7182 (white) / 12-nylon, average particle diameter d50: 35 μm), which is a material for the resin layer, is obtained by electrostatic coating. An inking roller was manufactured by coating with a thickness of 100 μm under the conditions of a load voltage of −70 KV, a discharge pressure of 0.15 MPa, a firing temperature preheating of 160 ° C. for 100 minutes, and a melting temperature of 190 ° C. for 20 minutes. The surface roughness at that time was Rmax; 13 μm, Rz; 9 μm. The lipophilicity of this roller surface was a contact angle with soybean oil; 16 °, and the water repellency was a contact angle with water; 90 °. And this was used for the ink transfer test of the same printing machine as Reference Example 1.
(Example 2)
The same iron roller substrate as in Example 1 above was degreased, blasted, and preheated at a temperature of 200 ° C. before spraying. Color) / 12-nylon, average particle diameter d50: 110 μm) by flame spraying method, spraying conditions (spraying machine conditions: pressure of propylene as fuel (0.1 MPa), pressure of oxygen as combustion-supporting gas ( 0.3 MPa), air pressure (0.12 MPa), material feeder conditions: air pressure (0.10 MPa), material supply rate 40 g / min, robot conditions: moving speed 300 mm / min, pitch 3 mm, rotation speed 100 rpm, pass Rotation 2, spraying distance 370mm, target film thickness: 250μm) coating thickness 260μm, and then to remove the surface waviness, It was produced inking roller and lightly polished finish at Ota-belt sander. The surface roughness at that time was Rmax; 18 μm, Rz; 13 μm. The oleophilicity of the roller surface was a contact angle with soybean oil; 11 °, and the water repellency was a contact angle with water; 89 °. And this was used for the ink transfer test of the same printing machine as Reference Example 1.

2. "Ink transfer test and roller cleaning test"
The rollers of the above Reference Example 1, Example 1 and Example 2 were used for the ink kneading rollers (4b1, 4b2, 4b3) of the inking unit (FIG. 2) of the offset printing machine (manufactured by Komori Corporation, Lithlon 440). A comparative evaluation test of ink transferability, ink washability, roller stripping property, calcium solid matter washability, solvent resistance, and wear resistance was carried out at the location. In the machine, the third color (yellow) inking unit, which is most likely to cause roller stripping, is equipped with three examples 1 and three examples 2 in the first color (black). went.
(1) Ink transferability When the roller was new, all three cases had no problem and the ink transfer was good.
(2) Ink washability The surface roughness of the roller of Reference Example 1 is Rmax; 3.2 S or less, whereas the surface roughness of Example 1 is Rz: 9 μm, and the surface roughness of Example 2 is , Rz: Despite being 13 μm, the ink washability was not inferior to that of Reference Example 1.

  Examples 1 and 2 are feared to have poorer cleanliness compared to Reference Example 1, but Examples 1 and 2 can be seen in the roughness chart of FIG. The value of Rz is increased by the amount of surface undulation, but when the undulation is corrected, the roughness waveform (FIG. 4) of Reference Example 2 is hardly changed, and the ink cleaning property is not significantly affected.

That is, if a uniform coating film thickness can be formed on a smooth surface having a surface roughness Rz of 1 to 15 μm by an electrostatic coating method or a flame spraying method, the polishing work in the subsequent process can be omitted, and the cost can be greatly reduced. I was able to confirm that.
Roller stripping property The copper plating roller of Reference Example 1 had a contact angle with water of 94 ° and a very high water repellency and good ink transfer properties when new, but after 3 to 6 months (printing unit Depending on the period, the roller surface was oxidized and changed to a blackish color. In particular, roller stripping occurred in the discolored portion. When it is terrible, water goes up to the vicinity of the ink source roller.

  When the roller was removed and the contact angle with water was measured, it was 87 ° at a portion with little discoloration (no stripping) and 75 ° at a discolored portion (roller stripping portion).

  That is, it has been found that roller stripping tends to occur when the contact angle with water decreases to around 75 °. The contact angle with soybean oil at the time of a new article was 47 °, the contact angle of the portion with little discoloration upon removal was 10 °, and the contact angle of the discolored portion was 16 °, both of which changed to lipophilicity. .

In view of the above, it has been found that the main factor for the occurrence of stripping of the copper roller is hydrophilicity by oxidation of the roller surface. (Lipophilicity is better than when new)
In this roller, the discolored portion is hardly improved by a method in which a normal calcium remover is placed on the roller and washed for about 10 minutes.

  The original color of the copper is restored by removing the roller, immersing the stock solution of the etchant in the waste, and further polishing the discolored portion physically (chemically) with a polishing powder (fine ceramic powder). The contact angle with water after the above-mentioned polishing and washing was little discolored, and all the discolored parts were at a level of 85 to 87 °, and the contact angles with soybean oil were all 15 to 16 °. Although it does not return to the state of time, in this state, roller stripping does not occur.

  However, since roller stripping occurs again in 3 to 6 months after polishing the roller, removing the roller from the machine and polishing the roller results in a great loss of work load for roller maintenance and reduction in operating rate. . On the other hand, in Examples 1 and 2, no roller stripping phenomenon occurred even after 9 months from the start of the test.

Since the inking units equipped with the rollers of Examples 1 and 2 were also tested with the rollers of Reference Example 1 except for the ink kneading rollers (4b ₁ , 4b ₂ , 4b ₃ ), these rollers were cleaned once a week. The roller of Examples 1 and 2 had almost no calcium adhesion and was easily removed by the calcium remover. Even after 9 months, the lipophilicity was observed. The water repellency was almost unchanged.
(4) Calcium solids washability After washing with a calcium remover to remove calcium solids adhering to the roller surface, the copper plating roller of Reference Example 1 had a black tint on the copper roller surface even after washing. It was difficult to remove the discolored part, and it was very difficult to remove the roller, soak the stock solution of the etchant in the waste cloth, and apply the polishing powder (fine ceramic powder) to polish the discolored part physically (chemically). The solid matter slightly adhering to the roller surfaces of Examples 1 and 2 was easily washed even by washing with a calcium remover once a week, and the detergency was very good.
(5) Solvent resistance / (6) Chemical resistance Washing oil or the like is used for normal inking roller cleaning, but sometimes ink (thinner) with high ink solubility is used. As a result of performing an immersion test using a thinner so that there was no problem even in such a rare case, the rollers of Examples 1 and 2 were also completely free of problems.

  The chemical resistance of typical chemicals (washing oil, blanket cleaner, UV roller cleaner, water supply roller cleaner, etc.) used in the vicinity of the printing press was also satisfactory.

  Hereinafter, experimental results of solvent resistance and chemical resistance of the inking roller according to the present invention will be shown.

  In addition, the solvent resistance and chemical resistance test method of the inking roller according to the present invention is a waste cloth in which the surface of the inking roller prepared in Examples 1 and 2 is impregnated with the solvent shown in Table 1 below. And the solvent shown in Table 1 below was dropped on the surface of the inking roller prepared in Examples 1 and 2 and the ink after 24 hours. This is a method (II) of visually observing the surface of the king roller.

Regarding the chemical resistance, the surface after 24 hours of dropping 5% hydrochloric acid had turned yellow, but the resin layer on the roller surface was not deteriorated, and there seems to be no problem in use. With regard to other solvents, there seems to be no problem in use.
(7) Abrasion resistance A test of about 21 million rotations of the plate cylinder was continued in the day and night operation for about 9 months, but no roller wear phenomenon was observed.

  Generally, it is said that the roller stripping is less likely to occur in the Rilsan roller than the copper roller. Therefore, a machine that is easy to perform roller stripping with CD102-4P manufactured by Heidelberg Co., Ltd., in which Reference Example 2 (Rilsan Roller) is used as a full-body full-rigid roller, is easy to carry out roller stripping. In the ink, roller stripping was selected, and the roller of Example 1 was replaced with all the second color (cyan) and third color (magenta) hard rollers, and a comparative test was performed. With the existing roller (Reference Example 2: Lilsan Roller), the color unevenness of the printed matter due to the roller stripping occurred unless it was washed once / week with the Calumum Remover. Even with the same cleaning for one year, there is no roller stripping trouble of the printed matter. The difference in physical properties between Reference Example 2 (rilsan resin) and Example 1 (12-nylon resin) was carried out with respect to a contact angle of 28 ° with soybean oil and a contact angle of 83 ° with water of Reference Example 2. The contact angle with soybean oil of Example 1 is 16 °, and the contact angle with water is 90 °. That is, even with the same polyamide-based resin, it was found that Example 1 is more lipophilic and water-repellent, so that it has excellent roller stripping resistance.

1 ... Plate copper 2 ... Rubber cylinder (Blanket cylinder)
3 ... Inking roller (rubber roller)
4a .. Ink kneading roller (copper clad roller; water cooling)
4b .. Ink kneading roller (copper plating roller)
4b ₁ .. Ink kneading roller (12-nylon roller)
4b _2.・ Ink kneading roller (12-nylon roller)
4b ₃ .. Ink kneading roller (12-nylon roller)
5 ... Ink kneading roller (rubber roller)
6 ... Ink call roller (rubber roller)
7 ... Ink roller (chrome plating roller)
8 ... Swim roller (rubber roller)
9 ... Reverse slip roller (Chrome plating roller)
10 ... Metering roller (rubber roller)
11 ... Water source roller (Chrome plating roller)
12 ... Swing rider roller (copper plating roller)
13 ... Metal roller (base material)
14 ... Metal layer (sprayed layer)
15 ... Resin layer

Claims (6)

A metal roller;
A metal layer having irregularities with a thickness of 100 to 250 μm and a surface roughness Rz of 20 to 60 μm formed by dense spraying a corrosion-resistant and wear-resistant metal material on the surface of the metal roller;
A resin layer having a smooth surface with a thickness of 20 to 150 μm and a surface roughness Rz of 1 to 15 μm provided by electrostatic coating on the surface of the metal layer,
The resin layer has an inking roller for an offset printing press having a contact angle with soybean oil of 30 ° or less and a contact angle with water of 80 ° or more. A metal roller;
A smooth surface having a thickness of 200 to 300 μm and a surface roughness Rz of 1 to 15 μm, formed by coating the metal roller surface with a resin having wear resistance, solvent resistance and chemical resistance by flame spraying. A resin layer having
The resin layer has an inking roller for an offset printing press having a contact angle with soybean oil of 30 ° or less and a contact angle with water of 80 ° or more.   The inking roller for an offset printing press according to claim 1, wherein the metal material is stainless steel, a Ni-based alloy, or an Al-based alloy.   The inking roller for an offset printing press according to any one of claims 1 to 3, wherein the resin is a polyamide-based resin.   The inking roller for an offset printing press according to any one of claims 1 to 4, wherein the resin is 12-nylon.   6. The inking roller for an offset printing press according to claim 1, wherein the surface of the resin layer is polished by SF polishing so that the surface roughness becomes Rmax 1 to 3 μm.