JP5473361B2 - Method for producing elastic roller for electrophotography - Google Patents

Description

  The present invention relates to a method for producing an electrophotographic elastic roller used in an electrophotographic image forming apparatus such as an electrophotographic copying apparatus, a printer, or an electrostatic recording apparatus.

  Some laser beam printers used in offices use a cartridge in which a central portion of a developing process including a developer container is integrated and detachable from the apparatus main body. From the viewpoint of reducing the environmental load, the study of reusing the components of such cartridges to effectively use resources has become active. Under such circumstances, an electrophotographic elastic roller used as a developing roller or the like in a laser beam printer adheres to and accumulates on the surface with paper dust or developer as it is used. The entire surface may be covered with paper dust or developer due to pressure contact or friction. When such an electrophotographic elastic roller to which paper dust or developer adheres is reused as it is, the surface state and resistance value of the electrophotographic elastic roller change, so that satisfactory performance can be obtained in the image forming apparatus. It may not be possible. Therefore, as a method for regenerating the electrophotographic elastic roller, Patent Document 1 proposes a method of removing the developer and contaminants adhered to the coating by blasting the coating formed on the surface of the developing roller. ing.

JP 2003-050506 A

  However, according to the study by the present inventors, the blasting process disclosed in Patent Document 1 is applied to the reproduction of an electrophotographic elastic roller having an elastic layer on the peripheral surface of the shaft core body. In addition to the removal of the developer fixed on the surface, the surface of the elastic layer may be damaged. In addition, a cleaning process for removing polishing powder remaining on the surface is required, and there is room for improvement in terms of workability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing an electrophotographic elastic roller that can easily remove the developer attached to the surface while maintaining durability during actual use as an electrophotographic elastic roller. The purpose is to do.

An electrophotographic elastic roller manufacturing method according to the present invention includes an axial core, an elastic layer formed around the axial core, and a coating layer formed on an outer peripheral surface of the elastic layer. In the method for producing a photographic elastic roller, a step of forming an uncured addition-type liquid silicone rubber containing hydrogenpolysiloxane having a hydrosilyl group in the shape of a roller around the shaft core, and the uncured addition mold Spraying water or alcohol or a mixture thereof on the surface of the liquid silicone rubber, and attaching droplets of water or alcohol or a mixture thereof to the surface of the uncured addition-type liquid silicone rubber; a hydroxyl group the droplet cured by heating the addition type liquid silicone rubber of the uncured deposited is the Rutotomoni, water and / or alcohol in the liquid droplets having a surface, with the uncured Reacting the hydrosilyl group of the said hydrogen polysiloxane type liquid silicone rubber, by generating a hydrogen gas, and forming an elastic layer having a plurality of recesses in the surface, the surface of the elastic layer And a step of providing a coating layer so as to enter the recess.

  According to the present invention, since the joint between the elastic layer and the resin layer exhibits excellent durability against shearing force in the rotational direction, an electrophotographic elastic roller having no problem in durability during actual use is obtained. Can do. Further, when the life of the electrophotographic elastic roller is exhausted, the developer adhered to the surface can be easily removed by peeling off the coating layer from the elastic layer. Moreover, there is little possibility of damaging an elastic layer. Therefore, it becomes easy to reproduce as an electrophotographic elastic roller.

It is a schematic sectional drawing which shows an example of the elastic roller for electrophotography of this invention. It is a schematic perspective view which shows an example of the elastic roller for electrophotography of this invention. It is a schematic block diagram which shows an example of the manufacturing apparatus applied to formation of the elastic layer of this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

  FIG. 2 is a perspective view of the electrophotographic elastic roller according to the present invention. FIG. 1 is a cross-sectional view of an electrophotographic elastic roller obtained by the manufacturing method according to the present invention. As shown in FIGS. 1 and 2, the elastic layer 2 is formed on the outer periphery of the shaft core body 1. The covering layer 3 is formed on the outer peripheral surface of the elastic layer 2.

<Shaft core>
Examples of the material constituting the shaft core 1 include the following materials. Alloys of iron, steel, aluminum, titanium, copper and nickel, stainless steel containing these metals, alloys of duralumin, brass and bronze, as well as composite materials in which carbon black and carbon fibers are solidified with plastic are known to exhibit rigidity and conductivity. Material. Further, the shape may be a columnar shape or a cylindrical shape having a hollow at the center.

<Elastic layer>
As the rubber material forming the elastic layer 2 of the present invention, an addition type liquid silicone rubber is used. The addition-type liquid silicone rubber is cured by an addition reaction between an alkenyl group-containing polysiloxane and a hydrosilyl group-containing hydrogen polysiloxane in the presence of a platinum catalyst. If water or alcohol is present during this crosslinking reaction, the hydroxyl group of water or alcohol reacts with the hydrosilyl group of hydrogenpolysiloxane to generate hydrogen gas, and this generated hydrogen gas forms a recess on the surface of the elastic layer. Is done. Since hydrogen gas is generated only at the location where water or alcohol is attached, a recess can be selectively formed only on the surface of the elastic layer without foaming inside the elastic layer where water or alcohol does not exist. The compression set characteristics are also maintained.

  Although it does not specifically limit as molecular weight of the polysiloxane containing an alkenyl group, 100,000 or more and 1 million or less are preferable. It is desirable that the polysiloxane has at least two alkenyl groups in one molecule. Although the kind of alkenyl group is not particularly limited, at least one of a vinyl group and an allyl group is preferable, and a vinyl group is particularly preferable because of its high reactivity with active hydrogen.

  In addition, the molecular weight in this invention is a weight average molecular weight when measured by gel permeation chromatography (GPC). That is, toluene as a solvent was allowed to flow through a column stabilized in a 40 ° C. heat chamber at a flow rate of 0.5 ml per minute, and 50 to 200 μl of a sample solution adjusted to 0.05 to 0.60 mass% was injected. And the weight average molecular weight of the sample was computed from the calibration curve created with several types of monodisperse polystyrene standard samples.

  The hydrogen polysiloxane containing a hydrosilyl group functions to form a recess on the surface of the elastic layer by dehydrogenating with a crosslinking agent for addition reaction in the curing step and with water or alcohol. The number of silicon-bonded hydrogen atoms in one molecule is 2 or more, and preferably 3 or more in order to optimally carry out the curing reaction. The molecular weight of the hydrogen polysiloxane is not particularly limited, but is preferably 1000 or more and 10,000 or less, and particularly preferably 1000 or more and 5000 or less with a relatively low molecular weight in order to appropriately perform the curing reaction.

  The blending amount of the hydrogenpolysiloxane of the addition-type liquid silicone rubber in the present invention is such that the number of hydrosilyl groups in the hydrogenpolysiloxane is 1.5 to 3.0 times the number of alkenyl groups in the polysiloxane. It is preferable that The hydrosilyl group of hydrogen polysiloxane is consumed in the competitive reaction of the addition reaction with the alkenyl group of polysiloxane and the dehydrogenation reaction with water or alcohol. In some cases, the compression set may deteriorate. On the other hand, if it exceeds 3.0 times, chemically unstable hydrosilyl groups remain excessively, and the physical properties of the electrophotographic elastic roller may change over time, which is not preferable.

  As a catalyst for the addition-type liquid silicone rubber, a platinum catalyst that exhibits a catalytic action in an addition reaction between polysiloxane and hydrogen polysiloxane or a dehydrogenation reaction between hydrogen polysiloxane and water or alcohol can be used. Specific examples thereof include chloroplatinic acid, platinum olefin complexes, platinum vinylsiloxane complexes, and platinum triphenylphosphine complexes. Regarding the blending amount of the catalyst, the platinum element amount is preferably 1 ppm or more and 1000 ppm or less with respect to 100 parts by mass of the polysiloxane. However, it is not limited to this range, and is appropriately selected depending on the target pot life, curing time, product shape, and the like.

Furthermore, according to the specific use of the electrophotographic elastic roller, a conductive agent or a non-conductive filler can be appropriately blended as a component necessary for the function required for the elastic layer itself. Examples of the conductive agent added for the purpose of imparting conductivity to the elastic layer include the following. That is, various conductive metals or alloys of carbon black, graphite, aluminum, palladium, silver, iron, copper, tin, stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, antimony oxide, molybdenum oxide, tin oxide − Various conductive metal oxides such as antimony oxide solid solution, tin oxide-indium oxide solid solution, and fine powders such as insulating substances coated with these conductive materials. Further, LiClO ₄ , NaClO ₄ perchlorate, or quaternary ammonium salt can be used as the ion conductive agent. Among these, carbon black can be suitably used because it is relatively easily available. Non-conductive fillers include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, zirconium silicate, aluminum silicate, talc, alumina and iron oxide.

  The method for forming the elastic layer 2 on the surface of the shaft core 1 is not particularly limited, and conventionally known methods for forming various rollers can be used. In particular, in a method in which an addition-type liquid silicone rubber is spray-coated around a shaft core using a ring-shaped coating head and then heated and cured, an uncured addition-type liquid silicone rubber formed in a roller shape is used. It is preferable because water or alcohol can be sprayed directly.

  Here, FIG. 3 shows a schematic explanatory diagram of a ring coater having a ring-shaped coating head that can be suitably used in the present invention. In the coating apparatus shown in FIG. 3, a column 5 is attached substantially vertically on the gantry 4, and a precision ball screw 6 is attached substantially vertically on the gantry 4 and the column 5. Two linear guides 7 are attached to the column 5 in parallel with the precision ball screw 6. The LM guide 8 is connected to the linear guide 7 and the precision ball screw 6 so that the rotary motion is transmitted from the servo motor 9 via the pulley 10 so that the LM guide 8 can be moved up and down. A ring-shaped coating head 11 that discharges the coating liquid is attached to the column 5 on the outer peripheral surface of the cylindrical shaft core body 1. Further, a bracket 12 is attached on the LM guide 8, and a work lower holder 13 and a work upper holder 14 for holding and fixing the shaft core 1 are attached to the bracket 12. The central axis of the ring-shaped coating head 11 is supported so as to be parallel to the moving direction of the workpiece lower holder 13 and the workpiece upper holder 14. Further, when the workpiece lower holding tool 13 and the workpiece upper holding tool 14 are moved up and down, the central axis of the discharge port that is an annular slit opened inside the coating head 11, the workpiece lower holding tool 13 and the workpiece upper holding tool 14 are held. The center axis of the tool 14 is adjusted to be substantially concentric. With such a configuration, the central axis of the discharge port that is an annular slit of the coating head 11 can be aligned with the central axis of the shaft core 1, and the inner peripheral surface of the ring-shaped coating head A uniform gap is formed between the outer peripheral surface of the shaft core body 1. The coating solution supply port 15 is connected to a material supply valve 17 via a coating solution transporting pipe 16. The material supply valve 17 includes a mixing mixer, a material supply pump, a material fixed amount discharge device, a material tank, and the like in front of the material supply valve 17 so that a fixed amount (a constant amount per unit time) can be discharged. Uncured addition-type liquid silicone rubber is weighed from a material tank by a material dispensing device and mixed by a mixing mixer. Thereafter, the uncured addition-type liquid silicone rubber mixed by the material supply pump is sent from the material supply valve 17 to the supply port 15 via the pipe 16. The uncured addition-type liquid silicone rubber fed from the supply port 15 passes through the flow path in the ring-type coating head 11 and is discharged from the nozzle of the ring-type coating head 11. In order to make the thickness of the silicone rubber constant, the discharge amount from the ring-shaped coating head nozzle and the supply amount from the material supply pump are made constant. By moving the held shaft core 1 upward in the vertical direction, the shaft core 1 moves in the axial direction relative to the coating head 11 and is uncured on the outer periphery of the shaft core 1. A roll-shaped layer 2 made of the additional liquid silicone rubber is formed.

  In the present invention, the surface of the uncured addition-type liquid silicone rubber formed into a cylindrical shape is sprayed with water, alcohol, or a mixture thereof, and then heated to cure the addition-type liquid silicone rubber and the elastic layer surface. The formation of the recesses proceeds. At least one coating layer is formed on the outer periphery of the elastic layer. Of the coating layers, the coating layer formed in contact with the elastic layer can be formed as follows. When a dispersion in which the composition forming the coating layer is dispersed is applied to the cured elastic layer, the dispersion penetrates into the recesses on the surface of the elastic layer, so that the coating layer is provided in the recesses. This acts as an anchoring effect for the coating layer to create adhesiveness, and in order to achieve durability, excellent adhesion to the shearing force in the rotational direction can be obtained even during actual use without strongly bonding the elastic layer and the coating layer. As shown, the coating layer does not peel off. In addition, since there is no chemical bond between the elastic layer and the coating layer, the coating layer can be easily peeled off from the elastic layer when the life of the electrophotographic elastic roller is exhausted. can do.

  As the size of the recess formed on the surface of the elastic layer, it is preferable that the average diameter of the circumference of the recess is 10 μm or more and 400 μm or less and the average depth is 5 μm or more and 200 μm or less. If the average diameter of the recesses is less than 10 μm or the average depth is less than 5 μm, the dispersion in which the composition forming the coating layer is dispersed may not permeate the recesses and a sufficient anchor effect may not be obtained. On the other hand, if the average diameter of the recesses is larger than 400 μm or the average depth is larger than 200 μm, the compression set of the electrophotographic elastic roller may be deteriorated. In addition, the average diameter and average depth of a recessed part were calculated | required as follows. When the surface of the elastic layer is photographed with a Keyence color 3D laser microscope VK-8700, and 3 points are selected every 120 ° from any one of the circumferences of the recesses using the Keyence shape analysis application VK-Analyzer The three-point circle diameter was determined. Similarly, the average value when the three-point circle diameter of 100 recesses was determined was taken as the average diameter of the recesses. Moreover, the maximum height difference of each recessed part was calculated | required from the 3D image of the elastic layer surface, and the average value of 100 recessed parts was made into the average depth of a recessed part.

Moreover, in this invention, it is preferable that the total area of the said several recessed part which occupies the surface of an elastic layer is 10% or more and 50% or less with respect to the area of the surface of this elastic layer. When the area of the concave portion is less than 10%, the ratio of the coating layer penetrating into the concave portion of the elastic layer is reduced, so that the anchor effect is weakened and the coating layer is easily peeled off during actual use. In addition, if the area of the recess is larger than 50%, the compression set of the electrophotographic elastic roller may deteriorate, which is not preferable. The surface of the elastic layer is the surface of the elastic layer in the region where the coating layer is provided. For example, when referring to the surface of the side surface portion (not the bottom surface portion) of a cylindrical elastic roller, the area of the surface of the elastic layer is [2π × (radius of shaft core + elastic layer thickness) ÷ 2 × (elasticity The length of the layer in the longitudinal direction of the roller)]. In addition, the area of the recessed part in this invention was calculated | required as follows. First, an arbitrary elastic layer surface of 1 cm ² was photographed with a Keyence color 3D laser microscope VK-8700. Subsequently, the area of the concave portion was obtained from a three-point circle diameter when three points were selected every 120 ° from an arbitrary point on the circumference of the concave portion by using Keyence's shape analysis application VK-Analyzer. The ratio per 1 cm ² when the area of all the recesses in the image is added is defined as the area of the recesses.

  The water sprayed on the uncured addition-type liquid silicone rubber is not particularly limited, and is preferably distilled water or ion exchange water. As the alcohol, known alcohols such as linear or branched alcohols having 1 to 10 carbon atoms such as methanol, ethanol, propanol, and butanol can be used. From the viewpoint of volatility and reactivity with hydrogenpolysiloxane, ethanol and isopropyl alcohol are preferred. Moreover, you may spray the liquid mixture of these water and alcohol. As a ratio in the case of mixing water and alcohol, it is preferable that water and alcohol are uniformly compatible. In the case of an alcohol having 3 or more carbon atoms that is hardly compatible with water, the alcohol is 2 wt% to 10 wt%, or 90 wt% to 98 wt% with respect to water so that one of them is excessive. It is preferable to do.

  As a method of spraying water or alcohol, a spray method capable of easily adjusting the size of the liquid to be sprayed and the spray amount is suitable. By precisely controlling the size of the droplets to be sprayed with water or alcohol and the location to be sprayed, the concave portions having the same size can be sprayed in a desired arrangement.

  The uncured addition-type liquid silicone rubber layer sprayed with water or alcohol is heat-treated to form an elastic layer. As the heat source, a far-infrared ceramic heater, a near-infrared heater, a lamp heater, a UV heater, or a micro heater that can heat the uncured addition-type liquid silicone rubber without contact is desirable.

  In this invention, the coating layer 3 according to a use is provided on the outer periphery of the elastic layer 2 formed as mentioned above. Examples of the material for forming the coating layer 3 include various polyamides, fluororesins, hydrogenated styrene-butylene resins, urethane resins, silicone resins, polyester resins, phenol resins, imide resins, and olefin resins. It is preferably one that can be cured by heat.

  In the coating layer 3, fine particles having a volume average particle diameter of 1 μm to 20 μm can be dispersed according to individual applications. Examples of such fine particles include polymethyl methyl methacrylate fine particles, silicone rubber fine particles, polyurethane fine particles, polystyrene fine particles, amino resin fine particles, and phenol resin fine particles.

<Coating layer>
The coating layer 3 can contain a conductive agent in order to adjust the electrical resistance of the entire electrophotographic elastic roller. Conductive agents include carbon black, graphite, conductive metal oxides, copper, aluminum, nickel, iron powder, or alkali metal salts that are ionic conductive agents, and ammonium salts, which are conductive agents having various electron conduction mechanisms. Can be used. These materials constituting the coating layer 3 can be dispersed using a conventionally known dispersion apparatus using sand mill, paint shaker, dyno mill, or pearl mill beads. The obtained dispersion is applied to the surface of the elastic layer 2 by spray coating or dipping. By adjusting the thickness of the coating layer, the surface of the coating layer can be roughened using the concave portions of the elastic layer without dispersing fine particles in the dispersion.

<Image forming apparatus>
Next, an example of an image forming apparatus having the electrophotographic elastic roller of the present invention will be described with reference to FIG.

  The image forming apparatus shown in FIG. 4 has four electrophotographic process cartridges 18 for forming yellow, cyan, magenta, and black images, respectively, and is provided in a tandem manner.

  The developing device 22 includes a developing roller 27 disposed opposite to the photosensitive drum 19 and a developing container 26 containing a developer 25. Further, the developer 25 is supplied to the developing roller 27 and the developer 25 remaining on the developing roller 27 without being used for development is scraped off. A developing blade 29 for regulating and frictionally charging is provided.

  The photosensitive drum 19 is uniformly charged to a predetermined polarity and potential by the charging roller 20. Image information is irradiated on the surface of the photosensitive drum 19 charged as a beam 21 to form an electrostatic latent image. Next, the developer 25 is supplied from the developing roller 27 onto the formed electrostatic latent image, and a developer image is formed on the surface of the photosensitive drum 19. In the image transfer device 24, the transfer conveyance belt 31 is stretched by a driving roller 32, a tension roller 33 and a driven roller 34, and a transfer roller 36 is installed inside the transfer conveyance belt 31 at a position facing the photosensitive drum 19. Yes. Then, by applying a bias to the electrostatic adsorption roller 35, the transfer material 30 is electrostatically adsorbed to the outer peripheral surface of the transfer conveyance belt 31, and the transfer material 30 is conveyed. When the transfer material 30 is conveyed to the transfer position, a bias having a polarity opposite to that of the developer image on the surface of the photosensitive drum 19 is applied to the transfer roller 36. As a result, the developer image is transferred to the transfer material 30. The transfer material 30 onto which the developer image has been transferred is sent from the transfer conveyance belt 31 to the fixing device 37, where the developer image is fixed on the transfer material 30 and printing is completed. On the other hand, the photosensitive drum 19 after the transfer of the developer image to the transfer material 30 is further rotated, and the surface of the photosensitive drum 19 is cleaned by the cleaning device 23.

  The electrophotographic elastic roller of the present invention can be used for the developing roller, charging roller, and transfer roller. In addition to the image forming apparatus described above, the image forming apparatus can be used for an intermediate transfer type image forming apparatus.

  The present invention will be described more specifically with reference to the following examples. The present invention is not limited to the following examples. First, various measurement methods and evaluation methods performed in Examples and Comparative Examples will be described.

[Measurement method of compression set]
The compression set in the present invention is the amount of deformation of the elastic layer when an electrophotographic elastic roller is compressed at a compression rate of 20% and left at a test temperature of 40 ° C. and a test humidity of 50% RH for 5 days. That is, when the thickness of the elastic layer before compression is T1, and the thickness of the elastic layer after compression is T2, the compression set is expressed by the following equation.

Compression set (%) = (T1-T2) / T1 × 100
A level where the compression set is 0.7% or less is A, 0.8% or more and 1.5% or less is B, and 1.6% or more is C.

[Durability of adhesion between elastic layer and coating layer]
The electrophotographic elastic roller of the present invention in which a coating layer was formed was incorporated in an electrophotographic process cartridge of a laser beam printer (HP Color LaserJet 3600 manufactured by Hewlett-Packard). Using this printer, 10,000 images were output continuously at a printing rate of 1% in an environment of 30 ° C. and 80% RH. At that time, A is the level at which the coating layer is not peeled off at all, B is the level at which a part of the coating layer is floating at the end of the non-image area, and more than half of the coating layer is floating or peeling off. The observed level was designated C.

[Peelability of coating layer after continuous image output]
After outputting 10,000 images continuously, a 3 cm cut was made at the edge of the coating layer with a cutter blade every 90 ° in the circumferential direction. A level at which all of the coating layer could be easily peeled off when the part with the notch was manually peeled off as a clue, and a level at which a part of the coating layer remained unpeeled or did not peel at all B.

<Example 1>
[Preparation of elastic layer]
A primer (DY39-051 made by Toray Dow Corning) is applied to a shaft made of free-cutting steel with a diameter of 6 mm and a length of 250 mm for the purpose of improving the adhesiveness with silicone rubber, and is heated at 150 ° C. for 30 minutes. Baking was performed.

  A base material in which 10 parts by mass of carbon black is blended with 100 parts by mass of dimethylpolysiloxane having a weight average molecular weight of 100,000 in which vinyl groups are substituted at both ends and 99 mol% or more of the main chain is a repeating unit of dimethylpolysiloxane. Prepared. Raven 890 (manufactured by Columbia Chemical) was used as the carbon black.

The following materials were blended with this base material to obtain an uncured addition type liquid silicone rubber.
-1 part by mass of a complex of chloroplatinic acid and divinyltetramethyldisiloxane as a curing catalyst.
-Methyl hydrogen polysiloxane: An amount in which the hydrosilyl group is 1.5 mol with respect to 1 mol of the vinyl group contained in the dimethylpolysiloxane substituted with the vinyl group.

  A shaft core body having an outer diameter of φ6 mm is vertically set on the shaft core body holding shafts (the shaft core body holding shaft 10 and the shaft core body lower holding shaft 9) of the ring coating machine having the ring-shaped coating head 11 shown in FIG. did. The shaft core holding shaft is vertically raised at 60 mm / s to move the shaft core body, and at the same time, uncured addition-type liquid silicone rubber is discharged at 5.0 ml / s to uncured on the outer periphery of the shaft core body. A layer of addition type liquid silicone rubber was formed.

  The uncured addition-type liquid silicone rubber was sprayed with distilled water in a sprayer, and the average diameter of the adhered distilled water droplets was measured with a laser microscope. The average diameter was 400 μm. The average diameter of the droplets was determined in the same manner as the average diameter of the recesses. That is, the droplets adhering to the uncured addition type liquid silicone rubber were photographed with a Keyence color 3D laser microscope VK-8700. Subsequently, using the Keyence shape analysis application VK-Analyzer, the three-point circle diameter when three points are selected every 120 ° from one point on the circumference of the droplet is obtained, and three points of 100 droplets are obtained. The average value of the circle diameter was taken as the average diameter of the droplets. The layer of uncured addition-type liquid silicone rubber sprayed with distilled water was rotated at 60 rpm while being irradiated with an infrared heating lamp (HYL25, manufactured by Hibeck) at an output of 1000 W for 4 minutes to be cured. Thereafter, for the purpose of removing reaction residues and unreacted low molecules in the cured addition-type liquid silicone rubber, an elastic roller for electrophotography having a thickness of 3 mm was obtained by heating with hot air at 200 ° C. for 4 hours. The surface of the obtained elastic roller for electrophotography was photographed with a laser microscope, and the average diameter, the average depth, and the area of the recesses were determined to be 320 μm, 160 μm, and 32%, respectively. The compression set of the electrophotographic elastic roller was 0.3%. These results are summarized in Table 1.

[Preparation of coating layer]
The following materials were mixed and 120 parts by mass of MEK was added.
-100 parts by mass of polyurethane polyol prepolymer (Takelac TE5060 manufactured by Mitsui Takeda Chemical).
-77 parts by mass of isocyanate (Nihon Polyurethane Coronate 2521).
-Carbon black (Mitsubishi Chemical MA-100) 20 mass parts.

  After 5 hours of dispersion and rotation with a ball mill, 6 parts of urethane fine particles (Negami Kogyo Art Pearl C-400 transparent) were added, and the mixture was further dispersed and rotated for 1 hour. The obtained electrophotographic elastic roller was immersed in this solution to form a coating film. After air drying, a coating layer having a thickness of 30 μm was formed by hot air treatment at 140 ° C. for 4 hours. The thickness of the coating layer was obtained by cutting a part of the roller and photographing with a digital microscope VHX-200 manufactured by Keyence. The thickness of the portion where no urethane fine particles were present was defined as the thickness of the coating layer. This was incorporated into an electrophotographic process cartridge of a laser beam printer as a developing roller, and after 10,000 continuous images were printed, peeling of the coating layer was observed, but there was no peeling at all. Next, after continuous image-drawing, the edge of the coating layer was cut with a cutter blade and the coating layer was peeled off, and all the coating layer was peeled off without remaining in the elastic layer. The results are shown in Table 1.

<Example 2>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that ethanol was used as the liquid sprayed onto the uncured addition-type liquid silicone rubber. The average diameter of the ethanol droplets adhering to the uncured addition-type liquid silicone rubber was 380 μm. The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 300 μm, 150 μm, and 30%, respectively, and the compression set was 0.3%. . When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 3>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the liquid sprayed onto the uncured addition-type liquid silicone rubber was a liquid in which distilled water and ethanol were mixed at a ratio of 1: 1. The average diameter of the droplets of the mixed solution of distilled water and ethanol adhering to the uncured addition-type liquid silicone rubber was 400 μm. The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 320 μm, 160 μm, and 28%, respectively, and the compression set was 0.4%. . When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 4>
An elastic roller for electrophotography was obtained in the same manner as in Example 1 except that the aperture of the nozzle of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 150 μm. . When the average diameter, average depth, and area of the concave portions on the surface of the cured elastic roller for electrophotography were determined, they were 120 μm, 60 μm, and 30%, respectively, and the compression set was 0.2%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 5>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the sprayer nozzle was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 250 μm. . When the average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined, they were 200 μm, 100 μm, and 31%, respectively, and the compression set was 0.2%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 6>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 10 μm. . When the average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined, they were 10 μm, 5 μm, and 35%, respectively, and the compression set was 0.4%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 7>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 500 μm. .

  When the average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined, they were 400 μm, 200 μm, and 28%, respectively, and the compression set was 0.7%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 8>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that distilled water was sprayed onto the uncured addition-type liquid silicone rubber so that the area of the concave portion on the surface of the cured electrophotographic elastic roller was 10%. The average diameter and average depth of the concave portions on the surface of the cured electrophotographic elastic roller were determined to be 330 μm and 160 μm, respectively, and the compression set was 0.3%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 9>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that distilled water was sprayed onto the uncured addition-type liquid silicone rubber so that the area of the concave portion on the surface of the cured electrophotographic elastic roller was 50%.

  When the average diameter and average depth of the recesses on the surface of the cured electrophotographic elastic roller were determined, they were 300 μm and 150 μm, respectively, and the compression set was 0.7%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 10>
Elastic roller for electrophotography in the same manner as in Example 1 except that the amount of the hydrosilyl group of methyl hydrogen polysiloxane is 3.0 mol with respect to 1 mol of vinyl group contained in dimethylpolysiloxane substituted with vinyl group. Got. The average diameter of the distilled water droplets adhering to the uncured addition type liquid silicone rubber was 400 μm. The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 320 μm, 160 μm, and 40%, respectively, and the compression set was 0.6%. . When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 11>
Elastic roller for electrophotography in the same manner as in Example 1 except that the amount of the hydrosilyl group of methylhydrogenpolysiloxane is 2.0 mol with respect to 1 mol of vinyl group contained in dimethylpolysiloxane substituted with vinyl group. Got. The average diameter of the distilled water droplets adhering to the uncured addition type liquid silicone rubber was 400 μm. The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 320 μm, 160 μm, and 40%, respectively, and the compression set was 0.6%. . When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 12>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 8 μm. .

  The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 6 μm, 3 μm, and 44%, respectively, and the compression set was 0.2%. When the durability of adhesion between the elastic layer and the coating layer was confirmed in the same manner as in Example 1 after continuous image output, the coating layer was peeled off at a part of the end of the non-image area. Moreover, when the peelability of the coating layer was evaluated in the same manner as in Example 1, all of the coating layer was peeled off. These results are shown in Table 1.

<Example 13>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 610 μm. .

  The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 500 μm, 260 μm, and 27%, respectively, and the compression set was 1.0%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 14>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that distilled water was sprayed onto the uncured addition-type liquid silicone rubber so that the area of the concave portion on the surface of the cured electrophotographic elastic roller was 80%.

  When the average diameter and the average depth of the concave portions on the surface of the cured electrophotographic elastic roller were determined, they were 300 μm and 150 μm, respectively, and the compression set was 1.2%. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 15>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that distilled water was sprayed onto the uncured addition-type liquid silicone rubber so that the area of the concave portion on the surface of the cured electrophotographic elastic roller was 5%. The average diameter and average depth of the concave portions on the surface of the cured electrophotographic elastic roller were determined to be 330 μm and 160 μm, respectively, and the compression set was 0.2%. When the durability of adhesion between the elastic layer and the coating layer was confirmed in the same manner as in Example 1 after continuous image output, the coating layer was peeled off at a part of the end of the non-image area. Moreover, when the peelability of the coating layer was evaluated in the same manner as in Example 1, all of the coating layer was peeled off. These results are shown in Table 1.

<Example 16>
Elastic roller for electrophotography in the same manner as in Example 1 except that the amount of the hydrosilyl group of methyl hydrogen polysiloxane is 1.0 mol with respect to 1 mol of vinyl group contained in dimethylpolysiloxane substituted with vinyl group. Got. The average diameter of the distilled water droplets adhering to the uncured addition type liquid silicone rubber was 400 μm. The average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined to be 320 μm, 160 μm, and 33%, respectively, and the compression set was 0.9%. . When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 17>
Elastic roller for electrophotography in the same manner as in Example 1 except that the amount of the hydrosilyl group of methyl hydrogen polysiloxane is 5.0 mol with respect to 1 mol of vinyl group contained in dimethylpolysiloxane substituted with vinyl group. Got. The average diameter of the distilled water droplets adhering to the uncured addition type liquid silicone rubber was 400 μm. Further, when the average diameter, average depth, and area of the concave portions on the surface of the cured electrophotographic elastic roller were determined, they were 320 μm, 160 μm, and 33%, respectively, and the compression set was 0.3%. . However, the hardness changed with time, and after one month, the hardness measured by ASKER C type manufactured by Kobunshi Keiki was increased by 2 °. When the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated in the same manner as in Example 1 after continuous image formation, all were good. These results are shown in Table 1.

<Example 18>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that the aperture of the atomizer was adjusted so that the average diameter of the droplets of distilled water adhering to the uncured addition-type liquid silicone rubber was 10 μm. .

  When the average diameter, average depth, and area of the recesses on the surface of the cured electrophotographic elastic roller were determined, they were 10 μm, 5 μm, and 14%, respectively, and the compression set was 0.2%. As a preparation of the coating layer, 100 parts by mass of lactone-modified acrylic polyol (Dacel Chemical Industries Plaxel DC2009) and 4 parts by mass of carbon black (Mitsubishi Chemical MA-100) were added to 250 parts by mass of MIBK, and 12 hours with a paint shaker. Dispersed. After adding 8 parts by mass of an isocyanurate type trimer of hexamethylene diisocyanate (Asahi Kasei Duranate TPA-B80E) to 100 parts by mass of this dispersion, the mixture was further dispersed and rotated in a ball mill for 1 hour. A film is formed by immersing the obtained electrophotographic elastic roller in this solution, and after air drying, the coating layer having a thickness of 5 μm is formed by hot air treatment at a temperature of 160 ° C. for 2 hours. An elastic roller for electrophotography was obtained.

  This was incorporated in an electrophotographic process cartridge of a laser beam printer as a charging roller, and after continuous image output, the durability of adhesion between the elastic layer and the coating layer and the peelability of the coating layer were evaluated. These results are shown in Table 1.

<Comparative Example 1>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that toluene was used as the liquid sprayed onto the uncured addition-type liquid silicone rubber. The average diameter of the toluene droplets adhered to the uncured addition type liquid silicone rubber was 130 μm. However, no recess was formed on the surface of the cured electrophotographic elastic roller. The compression set was 0.2%. In order to confirm the durability of the adhesion between the elastic layer and the coating layer, the continuous image was printed in the same manner as in Example 1. When the 3,000 sheets were printed, the coating layer started to peel off, and the image was printed further. I couldn't. When the coating layer started to peel off, the image formation was stopped and the peelability of the coating layer was evaluated in the same manner as in Example 1. As a result, all the coating layers were peeled off. These results are shown in Table 2.

<Comparative example 2>
An electrophotographic elastic roller was obtained in the same manner as in Example 1 except that nothing was sprayed onto the uncured addition-type liquid silicone rubber. No concave portion was formed on the surface of the cured electrophotographic elastic roller, and the compression set was 0.2%. In order to confirm the durability of the adhesion between the elastic layer and the coating layer, the continuous image was printed out in the same manner as in Example 1. As a result, the coating layer started to peel off when 2,800 sheets were printed, and the image was printed further. I couldn't. When the coating layer started to peel off, the image formation was stopped and the peelability of the coating layer was evaluated in the same manner as in Example 1. As a result, all the coating layers were peeled off. These results are shown in Table 2.

<Comparative Example 3>
An electrophotographic elastic roller was obtained in the same manner as in Example 18 except that nothing was sprayed onto the uncured addition-type liquid silicone rubber. No concave portion was formed on the surface of the cured electrophotographic elastic roller, and the compression set was 0.1%. In order to confirm the durability of the adhesion between the elastic layer and the coating layer, the continuous image was printed in the same manner as in Example 18. When the 3,000 sheets were printed, the coating layer began to peel off, and the image was printed further. I couldn't. When the coating layer started to peel off, the image formation was stopped and the peelability of the coating layer was evaluated in the same manner as in Example 18. As a result, all the coating layers were peeled off. These results are shown in Table 2.

1: Shaft core 2: Elastic layer 3: Covering layer

Claims (4)

In a method for producing an electrophotographic elastic roller having a shaft core, an elastic layer formed around the shaft core, and a coating layer formed on the outer peripheral surface of the elastic layer,
Forming a roller-shaped uncured addition-type liquid silicone rubber containing hydrogenpolysiloxane having a hydrosilyl group around the shaft core; and
The surface of the uncured addition-type liquid silicone rubber is sprayed with water or alcohol , or a mixture thereof, and droplets of water, alcohol, or a mixture thereof are sprayed onto the surface of the uncured addition-type liquid silicone rubber. A process of adhering to,
The addition type liquid silicone rubber of the uncured said droplets adhering cured by heating the surface Rutotomoni, the hydroxyl groups of water and / or alcohol in the liquid droplets, the addition type liquid silicone rubber of the uncured A step of forming an elastic layer having a plurality of recesses on the surface by reacting with a hydrosilyl group of the hydrogen polysiloxane to generate hydrogen gas ;
And a step of providing a coating layer on the surface of the elastic layer so as to enter the concave portion.   The average diameter of the recesses is 10 μm or more and 400 μm or less, the average depth is 5 μm or more and 200 μm or less, and the total area of the plurality of recesses on the surface of the elastic layer is 10% with respect to the surface area of the elastic layer The production method according to claim 1, wherein the production method is 50% or less.   The production according to claim 1 or 2, wherein the number of hydrosilyl groups contained in the hydrogen polysiloxane with respect to the number of alkenyl groups contained in the polysiloxane in the uncured addition-type liquid silicone rubber is 1.5 to 3.0 times. Method.   The manufacturing method according to any one of claims 1 to 3, wherein the step of forming the uncured addition-type liquid silicone rubber into a roller shape is performed using a ring-shaped coating head.

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