JP4845302B2 - Image forming apparatus roller manufacturing method, dip coating apparatus, and image forming apparatus roller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a roller for an image forming apparatus having a resin coating layer on the surface of a roller used in an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and a toner flight recording apparatus. The present invention relates to a dip coating apparatus and an image forming apparatus roller manufactured by the manufacturing method.
[0002]
[Prior art]
Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, a one-component toner is supplied to an image forming body such as a photoreceptor holding an electrostatic latent image, and the toner is attached to the latent image. As an image forming method to be visualized, a pressure development method is known (US Pat. Nos. 3,151,2012 and 3,731,146).
In this pressure development method, various rollers such as a developing roller, a toner supply roller, a transfer roller, a charging roller, and a cleaning roller are used.
[0003]
As shown in the schematic cross-sectional view of FIG. 3, these image forming apparatus rollers 20 have silicone rubber, NBR (acrylonitrile-butadiene copolymer rubber), EPDM (ethylene-propylene-ethylene) on the outer periphery of a shaft 22 made of metal or the like. A roller 21 is formed by forming an elastic layer 23 made of an elastic material obtained by adding a conductive agent to elastic rubber or foam such as diene copolymer rubber) or polyurethane rubber, if necessary, to provide conductivity, In order to control the chargeability and adhesion to toner, or to control the frictional force between the image forming body and the layered blade, and to prevent the photoreceptor from being soiled by an elastic body, a coating layer made of resin or the like as necessary 24 is provided on the surface of the conductive elastic layer 23.
[0004]
Such a resin coating layer 24 is formed by applying a coating solution obtained by dissolving a resin or the like in a solvent onto the conductive elastic layer 23 by a dip coating method, a roll coater method, a doctor blade method, a spray method, or the like, and then drying. -Form by curing. Among these methods, when forming the resin coating layer 24 by the dip coating method, the dip coating apparatus 11 as shown in FIG. 4 is used. In the dip tank 12 of the dip coating apparatus 11, a coating liquid 17 is supplied from a supply port 13 via a pump 15 and discharged from a discharge port 14 via a pump 16.
[0005]
However, in the conventional dip coating apparatus, if the coating liquid 17 is supplied into the dip tank 12, the dip tank 12 flows in the direction of the arrow in the dip tank 12 and the flow direction and flow velocity become nonuniform. The retention part 17a of a coating liquid will arise in the inside. In particular, in the case of a coating solution for a charging roller having a tendency to increase viscosity, the phenomenon of occurrence of a staying portion is remarkable because the flow rate becomes slow.
[0006]
In such a stay part, the viscosity of the coating liquid becomes non-uniform, the film pressure of the coating film formed on the roller surface becomes non-uniform, and the coating liquid component and the non-uniform viscosity of the coating liquid are accompanied. There has been a drawback that current values are likely to vary. In addition, since a uniform flow of the coating liquid is not maintained, when a coating liquid whose viscosity increases with time is applied, the viscosity of the coating liquid increases in the dip tank 12 and the viscosity increases. In particular, when the production is continued for a long time, the viscosity of the coating liquid in the dip tank 12 becomes extremely non-uniform, causing deterioration of workability and yield. It was.
[0007]
Therefore, in order to eliminate the occurrence of the staying part as described above, the present inventor tried to flow the coating liquid of the part that seemed to stay by increasing the flow rate of the pump 15 and increasing the flow rate. However, it has been found that this method only increases the speed of the portion with a high flow rate and has little effect on the portion with a low flow rate.
Next, the bottom 12a of the dip tank 12 was formed in an inverted pyramid shape as shown in FIG. 5, and a supply port 13 was provided at the lower end of the dip tank 12 to try to eliminate the retention. With this structure, a slight effect was observed compared to that shown in FIG. 4, and it was confirmed that the staying portion was somewhat smaller as shown by the staying portion 17b, but it was still insufficient.
[0008]
[Problems to be solved by the invention]
The present invention eliminates the above-mentioned conventional drawbacks, and when a resin coating layer is formed on the roller surface by a dip coating method, the image formation can be formed with a uniform thickness and uniform components. It is an object of the present invention to provide an apparatus roller manufacturing method, a dip coating apparatus used for carrying out the manufacturing method, and an image forming apparatus roller manufactured by the method.
[0009]
[Means for Solving the Problems]
As a result of intensive research to achieve the above object, the present inventors have formed a resin coating layer on the roller surface by a dip coating method to produce a roller for an image forming apparatus. A flow straightening plate is provided on the side of the working liquid supply port to make the flow direction and flow velocity of the supplied coating liquid uniform, and the roller is immersed in this coating liquid to form a coating film on the roller surface, which is then dried and cured. Thus, it has been found that a roller for an image forming apparatus in which a uniform resin coating layer is formed can be obtained. The present invention has been completed based on such findings.
[0010]
That is, the method for manufacturing a roller for an image forming apparatus according to the present invention is a method for manufacturing a roller for an image forming apparatus in which a resin coating layer is formed on the roller surface by a dip coating method, and a current plate on the coating liquid supply port side of the dip tank. Is characterized in that the flow direction and flow velocity of the coating liquid in the dip tank are made uniform.
[0011]
The dip coating apparatus of the present invention is used when manufacturing a roller for an image forming apparatus having a resin coating layer on the roller surface, and forms a coating film on the roller surface by immersing the roller in the coating liquid in the dip tank. The dip tank is provided with a coating liquid supply port and a discharge port, and a rectifying plate is provided on the supply port side, so that the flow direction and flow velocity of the coating liquid in the dip tank are made uniform. It is characterized by being designed.
In this case, the dip tank has a quadrangular shape and a bottom portion having an inverted pyramid shape, a coating liquid supply port is coupled to the lower end of the bottom portion, and a plurality of rectifying plates face upward from below the bottom portion. In addition, it is effective to arrange them so as to gradually spread while keeping the distance from each other evenly according to the shape of the inverted pyramid, and the plurality of rectifying plates are comb-shaped at their upper ends. Or what is arrange | positioned so that a grid | lattice form may be formed is effective.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a method for forming the coating film coating layer 24 on the roller surface by the dip coating method when the roller 20 for an image forming apparatus having the resin coating layer 24 on the surface of the roller 21 described with reference to FIG. FIG. 2 is a perspective view of the dip coating apparatus 1 in which a roller 21 is immersed in a coating liquid 10 in a dip tank 2 to form a coating film on the roller surface.
[0013]
The dip tank 2 in which the coating liquid is stored has a supply port 3 and a discharge port 4 for the coating solution, and is discharged from the discharge port 4 when the coating solution 10 supplied from the supply port 3 overflows. Yes. The dip tank 2 is provided with a rectifying plate 5 on the supply port 3 side so that the flow direction and flow velocity of the coating liquid 10 in the dip tank 2 are made uniform.
[0014]
The bottom surface 2a of the dip tank 2 is formed in an inverted pyramid shape, and the supply port 3 is arranged at the top (lower end city). It is preferable that the rectifying plate 5 gradually expands from the bottom to the top in accordance with the inverted pyramid shape while keeping the distance from each other uniform.
In the configuration example shown in FIG. 1, each of the rectifying pieces 5 b is arranged such that the upper surface opening 5 a has a comb shape in the configuration example shown in FIG. 1, and the upper surface opening 5 a has a lattice shape in the configuration example shown in FIG. 2. The coating liquid 10 that is provided and supplied from the supply port 3 is uniformly supplied into the dip tank 2.
[0015]
The spacing between the current plates is preferably small for uniformity, but due to structural limitations, the size of the dip tank, the characteristics of the coating solution (viscosity, thickening tendency, etc.), and the flow rate It is preferable to select as appropriate. For example, when arranging the rectifying plates in a comb shape, the interval is preferably about 5 to 100 mm, and when arranging the rectifying plates in a square lattice shape, one side is about 5 to 100 mm. Is preferred.
The height of the current plate (the length in the flow direction) is not particularly limited, but is preferably about 30 mm or more, and particularly preferably has a lower end positioned in the vicinity of the supply port.
[0016]
In the dip coating apparatus 1 as described above, the coating liquid 10 supplied from the supply port 3 is supplied into the dip tank 2 with the flow direction and flow velocity made uniform, and no staying portion is generated. In this way, after the roller 21 is immersed in the coating liquid 10 uniformly supplied into the dip tank 2 to form a coating film on the roller surface, the roller is pulled up and dried to cure the coating film. As a result, the image forming apparatus roller 20 having the resin coating layer 24 having a uniform layer thickness on the surface of the roller 21 can be obtained.
[0017]
The image forming apparatus roller 20 manufactured in this way is particularly suitable as a charging roller, a cleaning roller, or the like.
As described with reference to FIG. 3, the image forming apparatus roller 20 has a structure in which an elastic layer 23 is formed on the outer side of a shaft 22 made of metal or the like, and a resin coating layer 24 is formed on the surface thereof. is there.
The rubber-like elastic body forming the elastic layer is not particularly limited, and can be arbitrarily selected from those conventionally used in rollers for image forming apparatuses, but is solid rubber or urethane rubber. It is preferable for image formation.
When the elastic layer is conductive, a conductive agent is added to the rubber elastic body. As the conductive agent, an ionic conductive agent or an electronic conductive agent is used.
[0018]
In order to manufacture a roller using a foam as a raw material, there are a mechanical froth method, a water foaming method, a foaming agent froth method, etc. In the present invention, it is preferable to use a mechanical floss method.
In order to manufacture a foam roller by mecal calfloss, a shaft made of metal or the like is arranged in advance, and a foam raw material foamed by mechanical stirring is injected into a mold having a preheated inner surface, and reaction hardening is performed. Alternatively, the foam raw material may be poured into a mold, and the reaction hardening may be performed while mixing an inert gas and adding mechanical stirring.
Here, the inert gas used in the mechanical froth method may be an inert gas in the polyurethane reaction, for example, in the case of a polyurethane reaction. In addition to an inert gas in a narrow sense such as helium, argon, xenon, radon, krypton, etc. And gases that do not react with polyisocyanate, such as nitrogen, carbon dioxide, and dry air.
[0019]
The thickness of the resin coating layer 24 is preferably in the range of 5 to 500 μm, particularly preferably 100 to 300 μm. If the thickness of the coating layer is less than 5 μm, the coating film is not sufficiently formed, and the coating film may be lost due to repeated printing by the image forming apparatus.
[0020]
As the resin constituting the resin coating layer, a cross-linkable resin is suitable, and the cross-linkable resin is a resin or cross-link that self-crosslinks by heat, catalyst, air (oxygen), moisture (water), electron beam, etc. A resin that crosslinks by reaction with an agent or other crosslinkable resin.
Examples of such crosslinkable resins include hydroxyl groups, carboxyl groups, acid anhydride groups, amino groups, imino groups, isocyanate groups, methylol groups, alkoxymethyl groups, aldehyde groups, mercapto groups, epoxy groups, unsaturated groups, etc. Fluorine resin, polyamide resin, acrylic urethane resin, alkyd resin, phenol resin, melamine resin, silicone resin, urethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, polyether resin, amino resin, acrylic resin, Mention may be made of urea resins and the like and mixtures thereof. Of these, fluorine resins, polyamide resins, acrylic urethane resins, alkyd resins, phenol resins, melamine resins, silicone resins, urethane resins, polyester resins, polyvinyl acetal resins, epoxy resins, and mixtures thereof are preferred, and alkyd resins are particularly preferred. , Phenol resin, melamine resin and mixtures thereof are preferable from the viewpoint of charging ability of the developer, non-contamination to the developer, reduction of frictional force with other members, non-contamination to the image forming body, and the like.
[0021]
As the crosslinkable resin, a catalyst and a crosslinking agent are used as necessary. Examples of the catalyst include radical catalysts such as peroxides and azo compounds, acid catalysts, basic catalysts, and the like. In addition, the crosslinking agent has one molecule of reactive group such as hydroxyl group, carboxyl group, acid anhydride group, amino group, imino group, isocyanate group, methylol group, alkoxymethyl group, aldehyde group, mercapto group, epoxy group, and unsaturated group. A compound having a molecular weight of 1000 or less, preferably a compound having a molecular weight of 500 or less, having two or more compounds therein, includes, for example, a polyol compound, a polyisocyanate compound, a polyaldehyde compound, a polyamine compound, and a polyepoxy compound.
This crosslinkable resin can be further charged with a charge control agent, lubricant, conductive agent, other resin, etc. as desired for the purpose of further improving the charging ability to the developer, reducing the frictional force with other members, and imparting conductivity. Various additives can be contained.
In the present invention, the resin coating layer 24 is formed by applying a coating liquid 10 in which a crosslinkable resin, a crosslinking agent, and various additives are dissolved or dispersed on the surface of the roller 21 using the dip coating apparatus 1 by the dip coating method. It is preferably formed by drying at a temperature higher than room temperature and crosslinking and curing.
[0022]
Examples of the solvent used for preparing the coating liquid 10 include alcohol solvents such as methanol, ethanol, isopropanol, and butanol, ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone, aromatic hydrocarbon solvents such as toluene and xylene, Aliphatic hydrocarbon solvents such as hexane, alicyclic hydrocarbon solvents such as cyclohexane, ester solvents such as ethyl acetate, ether solvents such as isopropyl ether and tetrahydrofuran, amide solvents such as dimethylformamide, chloroform, Examples thereof include halogenated hydrocarbon solvents such as chloroethane, water-based paints such as acrylic paints, and mixed solvents thereof.
There is no particular limitation on the type of image forming apparatus to which the roller for image forming apparatus of the present invention can be attached.
[0023]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Example 1
《Dip coating equipment configuration》
As shown in FIG. 1, a dip tank having an inverted pyramid bottom surface having a depth (depth to the supply port 3) of 9 cm below a square having a length of 17 cm, a width of 32 cm, and a height of 30 cm, and a circular supply port The aperture is 2.5 cm. A rectifying plate 5b having a height of 12 cm gradually spreads upward, and is arranged in a comb shape with a spacing of 30 mm at the upper surface opening 5a. The internal volume including the bottom of the inverted pyramid is 25 liters.
[0024]
《Production of resin layer forming roller》
A polyol composition was prepared by blending 2.85 parts by weight of acetylene black with 100 parts by weight of a polyether polyol having a molecular weight of 2500 and mixing using a mixer. After stirring and defoaming this polyol composition under reduced pressure, 13.33 parts by weight of crude MDI (crude metaxylylene diisocyanate) was added and stirred for 2 minutes, and 0.001 part by weight of dibutyltin dilaurate was added. Stir for 3 minutes. Next, this is cast in a metal mold on which a metal shaft is placed and heated to 90 ° C. in advance, and cured at 90 ° C. for 12 hours to form a conductive elastic layer 23 on the outer periphery of the metal shaft to form a roller 21. Got. The surface of the obtained roller 21 was polished to adjust the surface to a JIS 10-point average roughness of about 8 μmRz and the thickness of the conductive elastic layer to 3 mm. The Asker C hardness of the conductive elastic layer in the roller 21 was 65 °.
[0025]
<Formation of resin layer>
Next, a coating liquid 10 obtained by adding and dispersing 10 parts by weight of carbon black to 100 parts by weight of the resin component in an emulsion type water-based urethane resin is supplied from the supply port 3 of the dip tank 2 at a rate of 6 liters per minute. It was supplied at a speed (flow rate 20 cm / sec).
The roller 21 is immersed in the dip tank 2 to form a coating film on the surface of the roller 21, held and pulled up so that the longitudinal direction of the roller is positioned vertically, and heated at 100 ° C. for 5 hours, The roller 1 for an image forming apparatus having the resin coating layer 24 cured by crosslinking was produced.
The resin coating layer 24 on the roller surface had a uniform thickness.
When an image was printed using this image forming apparatus roller, no image unevenness was observed.
[0026]
Example 2
《Dip coating equipment configuration》
As shown in FIG. 2, a dip tank having an inverted pyramid bottom surface having a depth (depth to the supply port 3) of 9 cm below a square having a length of 17 cm, a width of 32 cm, and a height of 30 cm, and a circular supply port The aperture is 2.5 cm. A rectifying plate 5b having a height of 12 cm gradually spreads upward, and is arranged so as to form a square lattice having a side of 30 mm at the upper surface opening 5a. The internal volume including the bottom of the inverted pyramid is 25 liters.
[0027]
Except that this dip coating apparatus was used, the process was carried out in exactly the same manner as in Example 1 to produce an image forming apparatus roller 1.
The resin coating layer 24 on the roller surface had a uniform thickness.
When an image was printed using this image forming apparatus roller, no image unevenness was observed.
[0028]
Comparative Example 1
In Example 1, an image forming apparatus roller 20 was produced in the same manner as in Example 1 except that the rectifying plate 5 was not provided in the dip tank 2. The resin coating layer 24 on the roller surface had a non-uniform thickness.
When an image was printed using this image forming apparatus roller, image unevenness was observed, and the image quality was inferior to that of Example 1.
[0029]
【The invention's effect】
According to the present invention, when a resin coating layer is formed on a roller surface by forming a coating film on the roller surface by a dip coating method and drying and curing, the flow direction and flow velocity of the coating liquid supplied to the dip tank Since the coating film is formed by immersing the roller in the coating solution, a roller for an image forming apparatus having a resin coating layer having a uniform thickness can be produced. Further, the obtained roller for an image forming apparatus is excellent in characteristics.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a dip coating apparatus according to the present invention.
FIG. 2 is a perspective view showing another example of the dip coating apparatus according to the present invention.
FIG. 3 is a cross-sectional view schematically showing a roller for an image forming apparatus.
FIG. 4 is a perspective view showing a conventional dip tank.
FIG. 5 is a perspective view showing a dip tank which has been improved.
[Explanation of symbols]
1: Dip coating device 2: Dip tank 3: Supply port 4: Discharge port 5: Current plate 20: Roller for image forming device 21: Roller 22: Shaft 23: Conductive elastic layer 24: Resin coating layer

Claims (4)

  In a method for manufacturing a roller for an image forming apparatus in which a resin coating layer is formed on a roller surface by a dip coating method, the dip tank has a body portion and a bottom portion, and the body portion has a quadrangular cross-sectional shape and The bottom portion has an inverted pyramid shape, a coating liquid supply port is coupled to the lower end of the bottom portion, and a plurality of rectifying plates are formed from the bottom to the upper side in accordance with the inverted pyramid shape. Image formation characterized by using a tank in which the flow direction and flow velocity of the coating liquid in the dip tank are made uniform by being arranged so as to gradually spread while keeping the distance between them uniform. Manufacturing method of apparatus roller.  The method of manufacturing a roller for an image forming apparatus according to claim 1, wherein the plurality of rectifying plates are arranged so that their upper ends form a comb shape or a lattice shape.  A dip coating device that is used in manufacturing a roller for an image forming apparatus having a resin coating layer on a roller surface and forms a coating film on the roller surface by immersing the roller in a coating solution in a dip tank. The dip tank has a barrel portion and a bottom portion, the barrel portion has a square shape in cross section, the bottom portion has an inverted pyramid shape, and a coating liquid supply port is provided at the lower end of the bottom portion. By being connected and arranged so that the plurality of rectifying plates gradually spread from the bottom to the top of the bottom portion while keeping the distance from each other evenly according to the inverted pyramid shape, A dip coating apparatus characterized in that the flow direction and flow velocity of the coating liquid in the dip tank are made uniform.  The dip coating apparatus according to claim 3, wherein the plurality of rectifying plates are arranged so that their upper ends form a comb shape or a lattice shape.

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