KR101123267B1 - Manufacturing method of cylinder jacket for offset perfect printing presses - Google Patents

Abstract

The present invention relates to a method for manufacturing a jacket for an offset duplex printing apparatus. The method for manufacturing a jacket for an offset duplex printing apparatus according to the present invention has a rigid strengthening step of forming a wear resistant layer on a surface of a base plate fitted to a pressure cylinder of an offset printing apparatus and a wear resistant layer by pressing a base plate on which a wear resistant layer is formed. A film forming step of forming a film by applying a hydrophobic and oleophobic filler to the surface of the wear resistant layer so as to flatten the surface by pressing the protruding portion of the surface and to fill a plurality of voids present in the wear resistant layer. It is characterized by consisting of.

Description

Manufacturing method of cylinder jacket for offset perfect printing presses

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a jacket for printing, and more particularly, to a method of manufacturing a jacket for an offset printing apparatus, which is inserted into a cylindrical cylinder such as a pressure cylinder, which is a part of an offset duplex printing apparatus, and used to prevent ink staining.

Figure 1 discloses a schematic configuration diagram of the offset duplex printing apparatus. Referring to FIG. 1, the offset duplex printing apparatus 9 is composed of a plurality of printing units which are spaced apart from each other as main components. The printing unit is a combination of a plate cylinder 1 on which an ink roller and a water roller are mounted, a blanket cylinder 2 and an impression cylinder 3. In the offset double-sided printing apparatus 9, a plurality of printing units 4 are installed on the upper part and spaced apart from each other.

Briefly looking at the printing principle, the plate 1 is formed with a pattern of the shape to be printed, the printing ink is selectively applied only to this pattern by the repulsive force with water. The plate (1) is rotated and the rolling contact with the blanket (2), the cloud contact process, the pattern of the plate (1) is transferred to the blanket (2). The sheet of printing paper (p) is carried out between the blanket (2) and the impression (3), the ink transferred to the blanket (2) is transferred to the printing paper (p) again and the printing is made. Pressing cylinder 3 allows printing paper p to advance while rotating, and presses printing paper p toward blanket bucket 2 so that ink flows well from blanket bucket 2 to printing paper p. It performs the function of being able to be transferred.

When the patterns formed on each upper printing unit 4 are all transferred onto one printing paper p, the upper surface printing is completed. That is, as can be seen in Figure 1, each of the blanket cylinder 2 of the upper printing unit 4 is in contact with the upper surface of the printing paper (p), and thus printing on the upper surface of the printing paper (p). In the same principle, each of the blanket cylinders 2 of the lower printing unit 5 is in contact with the lower surface of the printing paper p, whereby the lower surface printing is performed simultaneously with the upper surface printing. In Figure 1, the printing paper (p) is shown as being connected long, but for convenience of explanation and consists of a single sheet.

In the offset duplex printing device 9 having the above-described configuration, ink backing is always pointed out as a problem. Referring to the apparatus of FIG. 1 as an example, the pressing cylinder 3 of the second lower printing unit 5 in the advancing direction of the printing paper p comes into contact with the upper surface of the printing paper p. The upper surface of the printing paper p passing through (5) has already been printed by transferring ink from the first and second upper printing units. Since the ink takes a certain time to dry after printing, the ink that is not dry on the upper surface of the printing paper (p) is buried in the impression tube (3) of the second lower printing unit (5). Ink deposited on the tender 3 may be poor in print quality by being deposited on another printing paper (p), which is called ink staining. Ink back staining usually occurs in all printing units except the first one or two printing units in the printing paper's advancing direction.

In the offset double-sided printing apparatus, a cylindrical jacket coated with a hydrophobic and oleophobic material is inserted into the outer circumferential surface of the tender to solve such ink staining. That is, the jacket is formed with a hydrophobic and oleophobic surface, so that ink does not transfer to the surface of the jacket and does not transfer even when the ink and water are emulsified.

As mentioned above, the jacket must not only be coated with a material having hydrophobicity and oleophobicity on its surface, but also wear resistant for long-term use. In the conventional printing jacket, a wear-resistant layer was formed on a stainless base plate by thermal spraying, and then a perfluorocarbon resin solution having hydrophobicity and oleophobicity was coated on the surface to prepare a jacket.

However, when the surface is treated in the above manner, there is a problem in that the thickness of the jacket cannot be controlled. In other words, offset printing requires considerable precision, so the thickness variation of the jacket is normally allowed only within the maximum range of 5 μm. In the above-described method, a film of 15 to 20 μm is formed in one coating, thus controlling the thickness of the entire jacket. Not easy The precision coating method can be used to control the thickness, but it is almost impossible to use the precision coating method because the width and length of the jacket are about 1m each.

On the other hand, when forming the wear-resistant layer by the spraying method, some of the powder is not completely melted by heat and remains protruding on the surface of the jacket, which not only affects print quality by itself. There was a problem in that the nonwoven fabric for cleaning the jacket is caught on the protruding portion, leaving a residue on the jacket to make the print quality poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide a method for manufacturing a jacket for an offset duplex printing apparatus which can effectively prevent ink back staining, and can easily perform thickness control while improving wear resistance.

In accordance with an aspect of the present invention, a method of manufacturing a pressurized jacket for an offset duplex printing apparatus includes a rigid strengthening step of forming a wear resistant layer on a surface of a base plate that is inserted into a presser of an offset printing apparatus, wherein the wear resistant layer is formed. Pressing the base plate while rolling contact with the cylindrical roller to press the protruding portion of the wear-resistant layer to flatten the surface and the filler of hydrophobic and oleophobic material to fill a plurality of voids present in the wear-resistant layer It is characterized in that it comprises a film forming step of forming a film by applying to the surface of the wear-resistant layer.

According to the invention, further comprising an adhesive layer forming step of forming an adhesive layer by spraying nickel on the surface of the base plate so that the adhesion between the base plate and the wear-resistant layer is reinforced, by spraying ceramic on the adhesive layer to form a wear-resistant layer It is preferable to form.

According to the present invention, in the adhesive layer forming step, the base plate is wrapped around and installed on the outer circumferential surface of the hollow cylindrical jig having the cooling air inlet and the cooling air outlet, and then the nickel is sprayed on the surface of the base plate. In order to cool the base plate, it is preferable to introduce and discharge the cooling air into the inlet and the outlet of the jig.

According to the present invention, after the film forming step, it is preferable to further include a regrinding step of flattening the surface by pressing the wear-resistant layer and the base plate on which the film is formed while rolling contact with the cylindrical roller.

In addition, according to the present invention, the filler is preferably a ceramic of 10 ~ 50nm.

In the method for manufacturing a jacket for an offset printing apparatus according to the present invention, by generating a lotus effect on the surface of the jacket using nano-scale ceramic particles, the surface of the jacket becomes hydrophobic and oleophobic, so that the backside of the ink is offset when printing the offset duplex. The advantage is that the phenomenon can be eliminated. In addition, the nano-ceramic particles form nano pores, thereby enhancing the hydrophobicity and oleophobicity of the surface of the jacket.

In addition, the nano-ceramic is filled with the gap between the wear-resistant layer and the adhesive layer and penetrates up to the base plate and thermally cured, thereby enhancing adhesiveness with the base plate, thereby increasing durability of the jacket.

In addition, in the present invention, by pressing the surface of the jacket by using a cylindrical roller to soften the portion protruding sharply by the thermal spraying to solve the residue phenomenon and the like can improve the print quality.

Hereinafter, a jacket manufacturing method for an offset duplex printing apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The jacket manufacturing method according to the present invention can be used for the manufacture of various cylindrical cylinders, for example, a presser, a plate, and the like used in a printing apparatus, but the present embodiment will be described using a presser as an example.

FIG. 2 is a schematic flowchart of a method of manufacturing a pressurized jacket for an offset duplex printing apparatus according to a preferred embodiment of the present invention, and FIG. 3 illustrates a change of a jacket according to a process of the method of manufacturing a pressurized jacket for an offset duplex printing apparatus shown in FIG. A schematic drawing showing.

2 and 3, the method for manufacturing a pressurized jacket for offset duplex printing apparatus according to a preferred embodiment of the present invention (S100) is a shot blasting step (S10), an adhesive layer forming step (S20), a wear-resistant layer forming step ( S30), the planarization step (S40), the film forming step (S50) and the regrinding step (S60).

In the shot blasting step S10, a shot blasting process is performed on the base plate 10 serving as the base material of the jacket j. Various materials may be used as the base plate 10 of the jacket for the offset printing apparatus, but stainless steel is used in this embodiment. The base plate 10 has a thickness of about 0.25 to 0.35 mm.

Shot blasting is made by injecting sand or metal particles into the compressed air and spraying the base plate 10 at a high pressure. When the shot blasting process, the contaminants existing on the base plate 10 are basically removed, and a plurality of uneven parts 11 are formed on the surface of the base plate 10 as shown in FIG. do. That is, the convex-concave portion 11 is formed by colliding with the surface of the base plate 10 while particles such as metal or sand are injected at high pressure. Because of the uneven portion 11, the base plate 10 not only widens the surface area but also increases the surface friction force, thereby generating an effect of improving the adhesion between the adhesive layer 20 and the base plate 10 to be described later.

After the shot blasting step S10, an adhesive layer forming step S20 is performed. The adhesive layer forming step (S20) is to allow the wear resistant layer 30 to be firmly attached to the base plate 10 when the wear resistant layer 30 to be described later is sprayed on the base plate 10. That is, the wear resistant layer 30 made of a ceramic material has a property of not being easily attached to the base plate 10 made of stainless steel. Therefore, the adhesive layer 20 is formed by interposing the base plate 10 and the wear resistant layer 30 between the base plate 10 and the wear resistant layer 30 having excellent adhesion to both the stainless base plate 10 and the ceramic wear resistant layer 30. As a result, the wear-resistant layer 30 can be firmly attached to the base plate 10.

Nickel is used in this embodiment as such a material. A plasma thermal spraying method is used to bond nickel to the base plate 10 to form an adhesive layer 20.

First, the base plate 10 having the uneven portion 11 formed thereon is wrapped and installed on the outer circumferential surface of the cylindrical jig 70 as shown in FIG. 4. The cylindrical jig (70) is hollow and has an inlet port (71) through which cooling air for cooling the jig (70) and the base plate (10) is formed on one side, and the cooling air flows out on the other side. Outlets 72 are formed, respectively.

In the present embodiment, among the spraying methods, in particular, a plasma spraying method is used. In the general spraying process, the spray powder is injected into the flame while emitting a flame of 1000 to 1500 ° C, whereas in the plasma spraying process, a plasma jet (DC arc) is used. Or a high frequency plasma (RF discharge) is used to generate a plasma having a high temperature of approximately 12,000 ° C., and a thermal spray material, that is, nickel particles are injected and melted into the plasma to be deposited on the base plate 10. Nickel particles as the thermal spraying material in this embodiment are formed to a size of about 25 ~ 30μm. Nickel deposited on the base plate 10 forms a coating film as shown in FIG. 3B to form an adhesive layer 20.

In order to increase the deposition rate of nickel or to ensure that Nitel is firmly deposited, it is most ideal to reach the base plate 10 in a state of being heated above the melting point of about 1400 ° C., and the base plate 10 is rapidly cooled. It is preferable. In addition, since the adhesive force decreases when the temperature of the base plate 10 rises, the cylindrical jig 70 performs a function of maintaining the temperature of the base plate 10 at about 20 to 25 ° C. while cooling air flows.

After the adhesive layer forming step (S20), a wear-resistant layer forming step (S30) is performed. Like the adhesive layer 20, the wear-resistant layer 30 is also formed by a plasma spraying method, which is performed by using ceramics instead of nickel as the material for the spraying. This ceramic has a high hardness and excellent wear resistance. In this embodiment, ceramic particles in which alumina (Al 2 O 3) and titania (TiO 2) are mixed in a weight ratio of about 1: 1 or 4: 6 are used. The mixed ceramic of alumina and titania as the material of the adhesive layer 20 is melted at approximately 1840 ° C., and the ceramic mixed with titania and alumina has high wear resistance, thereby increasing the durability of the jacket j.

However, since some of the mixed ceramics forming the wear resistant layer 30 are applied to the adhesive layer 20 in a state of not being completely melted, as shown in (c) of FIG. 3, the protrusions 31 protruding sharply. Can be formed. When the non-woven fabric for cleaning is washed off the jacket j due to the protrusions 31 and is caught on the protrusions 31, residues, etc., cause poor printing quality.

In the present invention, by pressing and pressing the protrusion of the wear-resistant layer 30 performs a flattening step (S40) to remove the protrusion and maintain the appropriate roughness. In the flattening step S40, a cylindrical roller 82 as shown in FIG. 5 is used. That is, after the jacket j is loaded on the surface plate 81 capable of linear reciprocating motion, the cylindrical roller 82 is pressed downward by using the hydraulic device 83. The roller 82 is pressed against the jacket j while being in contact with the jacket j as the jacket j reciprocates while being suspended on the shaft 84. In this embodiment, the roller 82 presses the surface of the jacket j with a force of 10 ~ 60Kg / Cm ² .

By this pressurization, as shown in FIG. 3D, the protrusions 31 of the wear resistant layer 30 are crushed and the roughness of the wear resistant layer 30 is also lowered. Although the ten point average roughness of the wear-resistant layer 30 before performing the planarization step S40 as shown in the state of the imaginary line in FIG. 3D is about 25 to 35 μRz, it is pressurized by the roller 82 in the planarization step S40. After that, the illuminance is lowered to about 20 to 30 µRz as shown by solid lines in FIG. However, although the protrusions are mostly flattened by pressurization, some of them may remain sharp at the ends and these may cause residue. However, this problem can also be solved in the film forming step (S50) to be described later.

 After the planarization step S40, the film forming step S50 is performed. The film forming step (S50) is to form the surface of the jacket (j) to be hydrophobic and oleophobic to prevent the ink backing phenomenon which is the biggest problem in offset duplex printing.

In order to make the surface of the jacket (j) hydrophobic and oleophobic, it is accessible in two aspects: structural and the nature of the coating material. Looking at the structural aspect, there are a number of pores of approximately 10 ~ 40μm size in the wear-resistant layer 30 and the adhesive layer 20, these pores are the wear-resistant layer 30 and the adhesive layer 20 and the base plate ( 10) not only decreases the adhesive force of the jacket (j) to reduce the wear resistance, but also water and oil particles infiltrate into the micron pores it is difficult to exhibit hydrophobicity and oleophobicity.

Accordingly, the pores in the wear resistant layer 30 and the adhesive layer 20 are filled with a filler made of ceramic particles having a size of 10 to 50 nm to enhance the wear resistance of the jacket j and to exert a so-called lotus effect. do. That is, on the nanoscale, the rougher surface than the smooth surface is more hydrophobic and oleophobic because the surface area contacted by water or oil particles is smaller. For example, in the case of the lotus surface, only 2 to 3% of the total area of the water droplet is in contact with the lotus surface. On the surface of the lotus, small projections of several nanometers are formed, and droplet droplets come into contact with these projections, so the contact area is small, so that the surface tension is lowered, so that water does not penetrate the leaves and flows easily.

In this embodiment, the particles of 10 to 50nm size are coated on the wear-resistant layer 30 so that the surface of the jacket is formed with nano-sized irregularities so that ink or water on the printing paper does not get on the jacket.

In addition, since the properties of the nano-ceramic particles forming the film 40 are hydrophobic, so that the lotus effect is further enhanced, the surface of the jacket j is hydrophobic and oleophobic. Various types of ceramic particles may be used, and liquid nano ceramics may be used. For example, a nano-ceramic may be used in which a composite cyclic multiple structure that connects the silicate via an oxygen atom and a polymer of functional groups such as alkoxy silane, silazoles, and phenol may be used.

If the size of the ceramic particles is less than 10nm is not preferable because it is not easy to manufacture the ceramic particles, if it exceeds 50nm it is not preferable because the lotus effect is slowed down and the thickness control of the coating 40 is not easy.

As described above, in this embodiment, by applying a nano-sized ceramic on the wear-resistant layer 30 to form the surface of the jacket (j) with hydrophobicity and oleophobicity, the problem of ink staining in offset duplex printing is solved It can also increase wear resistance

On the other hand, even if it has hydrophobicity and oleophobicity, in the case of general ceramics, the particle size is 40 ~ 50μm and can not be used because the thickness control is almost impossible when forming the film. In offset printing, the spacing and pressure between the tender and the blanket are very important factors in print quality. In other words, when the thickness of the jacket is increased and the pressure between the tenderness and the blanket is increased, the ink printed on the printing paper is excessively pressed, so that a phenomenon of spreading as a so-called moiré phenomenon occurs. In the printing apparatus to which the jacket according to the present embodiment is applied, the thickness of the base plate 10 of the jacket j is 0.25 mm, and the total thickness of the adhesive layer 20, the wear resistant layer 30, and the coating 40 is 0.05 mm. It should be formed to a degree, but in the case of general ceramics, since a coating having a thickness of about 40-50 μm is produced by a single coating, fine thickness control is impossible.

When the nano-sized ceramics are used as in this embodiment, the size of the particles is so small that the increased thickness during one coating of the coating is very fine, so that the overall thickness of the jacket can be easily controlled by controlling the number of coatings of the coating during the manufacturing process.

In addition, as shown in (f) of FIG. 3, the ceramic particles c are filled between the protrusions 31 and the protrusions 31, so that the sharp ends of the protrusions remaining even after the planarization step have a protruded degree. Will be lowered. This effect is called a blanket effect, and the problem caused by the residual non-woven cloth remaining on the protrusions by the blanket effect is solved.

After the film forming step S50 is completed, a regrinding step S60 of performing a surface polishing of the jacket j again in the same manner as the planarizing step S30 may be selectively performed. That is, after measuring the surface roughness of the jacket through the roughness measuring instrument, the regrinding step (S60) is performed only when the roughness is formed higher than the desired level, and when the desired level of roughness occurs, the regrinding step (S60) is performed. You don't have to. In the present invention, the surface roughness of the jacket is formed to about 25μm based on the ten-point average roughness (Rz).

As described above, the method for manufacturing a pressurized jacket for an offset duplex printing apparatus according to the present invention uses a nano-sized hydrophobic and oleophobic ceramic to fill the voids of the wear-resistant layer and the adhesive layer and to form the surface of the nano-unit jacket. The surface of causes the lotus effect. By this lotus effect, the ink backing phenomenon of the jacket is overcome.

In addition, by performing a planar polishing on the jacket using a cylindrical roller, the projections sharply formed by plasma spraying or the like are removed to form roughness suitable for print quality.

In addition, the nano-sized ceramic has the advantage that the durability of the jacket can be enhanced by filling the pores of the wear-resistant layer and the adhesive layer.

Reference numeral c, which is not described in FIG. 4, refers to nano ceramic particles introduced into the wear resistant layer 30 and the adhesive layer 20 in the film forming step.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. There will be. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

1 is a schematic configuration diagram of a printing cylinder of an offset duplex printing apparatus.

2 is a schematic flowchart of a method for manufacturing a tender jacket for an offset duplex printing apparatus according to a preferred embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a change in a jacket according to a process of a method of manufacturing a pressurized jacket for an offset duplex printing apparatus shown in FIG. 2.

4 is a schematic view for explaining the adhesive layer forming step and the wear-resistant layer forming step shown in FIG.

FIG. 5 is a schematic diagram for describing the planarization step illustrated in FIG. 2.

<Explanation of symbols for the main parts of the drawings>

S100 ... How to make a jacket for offset duplexer

S10 ... shot blasting step S20 ... adhesive layer forming step

S30 ... wear-resistant layer forming step S40 ... flattening step

S50 ... film forming step S60 ... regrinding step

10 ... base plate 20 ... adhesive layer

30 ... wear resistant layer 40 ... film

70 ... Jig 81 ... Table

82 ... roller 83 ... hydraulics

j ... jacket

Claims (7)

A rigid strengthening step of forming a wear-resistant layer on a surface of a thin plate-shaped base plate inserted into a cylindrical cylinder of an offset printing apparatus; A planarization step of flattening a surface by pressing the base plate on which the wear resistant layer is formed and pressing a protruding portion of the wear resistant layer; And And a film forming step of forming a film by applying a filler of hydrophobic and oleophobic material to the surface of the wear resistant layer so that a plurality of pores existing in the wear resistant layer are filled. Further comprising an adhesive layer forming step of forming an adhesive layer by spraying nickel on the surface of the base plate so that the adhesion between the base plate and the wear-resistant layer is reinforced, A pressure-sensitive jacket manufacturing method for an offset duplex printing apparatus, characterized in that to form a wear-resistant layer by spraying ceramic on the adhesive layer. delete The method of claim 1, In the adhesive layer forming step, after wrapping the base plate on the outer peripheral surface of the hollow cylindrical jig having a cooling air inlet and a cooling air outlet, Offset duplex printing, characterized in that to introduce the cooling air through the inlet of the jig and to discharge the cooling air through the outlet to cool the base plate in the process of spraying the nickel on the surface of the base plate. Method for manufacturing a jacket for a device. The method of claim 1, And a regrinding step of flattening the surface by pressing the base plate on which the wear-resistant layer and the coating layer are formed in contact with the cylindrical roller after the film forming step. The method of claim 1, In the flattening step, the base plate is a jacket manufacturing method for offset duplex printing apparatus, characterized in that pressed in contact with the cylindrical roller. The method according to claim 4 or 5, The cylindrical roller is a jacket manufacturing method for offset duplex printing apparatus, characterized in that for applying a force of 10 ~ 60Kg / Cm ² to the base plate. The method of claim 1, The filler is a jacket manufacturing method for offset duplex printing apparatus, characterized in that the ceramic 10 ~ 50nm.

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