JP2008129526A - Developing roller manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture a developing roller that achieves a satisfactory developing process by reducing variation in a quantity of toner to be conveyed. <P>SOLUTION: The developing roller manufacturing method for manufacturing a developing roller 1 that has a cover layer for attaching toner thereto includes a step of polishing the surface 3f of an elastic layer 3 forming the cover layer, with a grinding stone 21. The grinding stone 21 used for polishing the surface 3f has a particle size of #80 to #100 and has a dent depth of 0.60 to 0.81 mm observed by using an 8 or 12 mm diameter bit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a developing roller incorporated in an image forming apparatus such as a copying machine or a printer, and is intended to reduce the occurrence of image quality degradation such as “fogging” caused by the developing roller.

  In an image forming apparatus such as a copying machine, for example, a photosensitive drum holding an electrostatic latent image is used as an image carrier, and toner is supplied to the photosensitive drum to visualize the latent image on the photosensitive drum by adhesion of the toner. An apparatus as shown in FIG. 1 using a developing method (pressure developing method) is known.

  The developing roller 1 incorporated in this type of conventional apparatus is disposed in contact with the toner supply roller 11 for supplying the toner T and the photosensitive drum 12, and the toner supply roller 11 and the developing roller 1. The photosensitive drum 12 rotates in the direction of the arrow in the figure.

  The toner T adhering to the surface by the rotation of the toner supply roller 11 is supplied to the developing roller 1 and is carried on a coating layer 5 which will be described later, which is the outermost layer of the developing roller 1, and then a uniform thin layer is formed by the layering blade 13 To be arranged. As a result, the toner T uniformly arranged on the surface of the developing roller 1 adheres to the latent image on the photosensitive drum 12 to visualize the latent image, and then the toner image is formed on a medium such as paper by the transfer unit 14. Transcribe. Reference numeral 15 denotes a cleaning unit, and the cleaning blade 15a removes toner T remaining on the photosensitive drum 12 after transfer.

  That is, the developing roller has a function of feeding a constant amount of toner T to the photosensitive drum 12, and the toner conveyance amount is adjusted by tracing the outer surface of the developing roller 1 with the stratified blade 13. It was.

  However, in the conventional adjustment mechanism, the transport amount may vary greatly due to the large surface variation of the developing roller, and the occurrence of “fogging” or the like that affects the image quality is inevitable. Note that “fogging” refers to a phenomenon in which image unevenness occurs at a constant period.

On the other hand, as a conventional technique for solving the problems caused by the variation in the toner conveyance amount as described above, a coating layer made of a synthetic resin is formed on the outer surface of the developing roller to adjust the friction coefficient and the glossiness. Some attempts have been made (see, for example, Patent Document 1).
JP 2000-19835 A

  However, even with such a conventional developing roller, the problem due to the variation in the toner conveyance amount has not yet been fully satisfied.

  Therefore, the present inventor pays attention not to the outer surface of the coating layer but to the surface on which the coating layer is formed, and there is a numerical range suitable for the surface roughness and surface glossiness, and the numerical range is [JISB0601]. The 10-point average roughness (Rz) measured in accordance with JIS is in the range of 4 to 10 μm, and the specular gloss Gs (85 °) measured in accordance with [JIS Z8741] is 1.5 to 5%. It was found to be in the range.

  However, the present inventor has further found that the surface roughness and the specular gloss change according to the state of the grindstone when the surface is polished, and are not necessarily constant.

  The problem to be solved by the present invention is to easily manufacture a developing roller that realizes good development processing by reducing variations in the toner conveyance amount.

The present invention provides a developing roller for use in toner supply.
A developing roller characterized in that the surface of the main body of the developing roller is polished with a grindstone that satisfies the following conditions, and then a coating layer for carrying toner is formed on the polished surface. Manufacturing method.
Grinding wheel particle size: in the range of # 80 to # 100 Depth of penetration indicating the degree of particle bonding of the grinding wheel: Depth of penetration in the range of 0.60 mm to 0.81 mm (biting depth when using a bit with a diameter of 8 mm or a bit with a diameter of 12 mm )

  In the present invention, when polishing the main body of the developing roller, it is preferable that the grindstone is rotated in the range of 2000 rpm to 3000 rpm and the main body of the developing roller is rotated in the range of 30 rpm to 150 rpm.

  In the present invention, when the grindstone is brought into contact with the main body of the developing roller, the feed speed is preferably in the range of 2.5 mm / min to 10 mm / min.

  When the grindstone particle size and the bit bite depth of 8 mm in diameter or the bit bite depth of 12 mm in diameter are measured and a grindstone in a suitable numerical range is selected, the toner carried on the surface of the developing roller is substantially uniform over the entire circumference. The thickness is increased, and the influence of “fogging” or the like is greatly reduced. Therefore, according to the present invention, it is possible to easily manufacture a developing roller that realizes a good developing process.

  Hereinafter, an embodiment of a developing roller manufacturing method according to the present invention will be described in detail with reference to the drawings.

  2A and 2B are a perspective view and a cross-sectional view, respectively, of the developing roller 1 manufactured according to the present invention.

  As shown in FIG. 2, the developing roller 1 has a roller body 4 composed of a highly conductive shaft 2 and an elastic layer 3 integrally provided on the outer periphery of the shaft 2, and the surface of the roller body 4, that is, The coating layer 5 is formed on the surface 3 f of the elastic layer 3.

  In manufacturing the developing roller 1, the surface of the roller body 4, that is, the surface 3 f of the elastic layer 3 is polished with a grindstone.

  FIG. 3 is a schematic view illustrating an implementation situation in polishing the roller body 4.

  In FIG. 3, reference numeral 20 denotes a collect chuck that detachably fixes and holds the shaft 2 of the roller body 4. The collect chuck 20 can be freely rotated by a drive source (not shown). As a result, the roller body 4 can rotate at various rotational speeds starting from the collect chuck 20. Reference numeral 21 denotes a roller-shaped grindstone that can rotate around the axis O at various rotational speeds. The grindstone 21 can polish the surface 3f at various cutting speeds by approaching or separating in the Y direction orthogonal to the roller body 4.

  When the surface 3f is polished, the type of the grindstone can be appropriately selected according to the material of the elastic layer 3, but the particle size is in the range of # 80 to # 100 in accordance with [JISR6001], and [JISR6240 ], The biting depth when using a bit having a diameter of 8 mm or a bit having a diameter of 12 mm is preferably in the range of 0.60 mm to 0.81 mm. Specifically, when a bit having a diameter of 8 mm is used, the biting depth (mm) when the bit is rotated 120 degrees after being pressed with a load of 490 N or 785 N in a direction orthogonal to the surface of the grindstone. When a bit having a diameter of 12 mm is used, the biting depth (mm) when the bit is rotated 120 degrees after being pressed with a load of 490 N or 785 N in a direction orthogonal to the surface of the grindstone is measured. .

  By using the grindstone 21, the surface roughness of the surface 3f is in the range of 14 to 10 μm in terms of 10-point average roughness (Rz) measured in accordance with [JISB060], and the surface glossiness of the surface 3f is The specular gloss Gs (85 °) measured in accordance with [JISZ8741] is in the range of 1.5 to 5%.

  If the coating layer 5 is formed on the roller body 4 having such surface characteristics, the toner is uniformly carried on the roller body 4, so that occurrence of “fogging” or the like can be reduced. That is, a developing roller that realizes a good development process can be easily achieved by simply measuring the particle size of the grindstone 21 and the bit biting depth of 8 mm in diameter or the bit biting depth of 12 mm in diameter and selecting a grindstone in a suitable numerical range. Can be manufactured.

  Further, the rotational speeds of the roller body 4 and the grindstone 21 can be appropriately selected according to the material of the elastic layer 3, but the grindstone 21 is rotated in the range of 2000 rpm to 3000 rpm and the roller body 4 is rotated from 30 rpm to 150 rpm. It is preferable to rotate in the range.

  Furthermore, when the grindstone 21 is brought into contact with the roller main body 4, that is, the elastic layer 3, the feeding speed (cutting speed) can be appropriately selected according to the material of the elastic layer 3, but 2.5 mm / min to 10 mm. / Min is preferable.

  In polishing the surface 3f, it is most preferable to satisfy all suitable conditions for the type of the grindstone 21, the polishing speed (rotation speed), the cutting speed, and the polishing time. May be.

  In the developing roller 1 according to the present invention, the roller body 4 is not limited to a single layer structure having only the elastic layer 3 but may have a multilayer structure.

  The shaft 2 of the developing roller 1 is not particularly limited as long as it has good conductivity. For example, a metal core made of a solid metal such as iron, stainless steel, or aluminum, or a metal hollowed inside. A metal shaft such as a cylindrical body or a highly conductive plastic shaft can be used.

  The elastic layer 3 of the developing roller 1 is made of an elastomer and can contain other components such as a conductive agent as necessary. The elastomer used for the elastic layer 3 is polyurethane, silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber, styrene-butadiene rubber (SBR), butadiene rubber, isoprene rubber, polynorbornene. Examples thereof include rubber, butyl rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA), and mixtures thereof. Among these, polyurethane is preferable. In the elastic layer 3, the elastomer may be used as a non-foamed material, or the elastomer is chemically foamed using a foaming agent, or air is mechanically entrained and foamed like a polyurethane foam. For example, the elastomer may be used as a foam.

  Examples of the conductive agent that can be used for the elastic layer 3 include an electronic conductive agent and an ionic conductive agent. Electronic conductive agents include conductive carbon such as ketjen black and acetylene black, carbon black for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, and color (ink) subjected to oxidation treatment, etc. Carbon black, pyrolytic carbon black, natural graphite, artificial graphite, antimony-doped tin oxide, ITO, tin oxide, titanium oxide, zinc oxide and other metal oxides, nickel, copper, silver, germanium and other metals, polyaniline, polypyrrole Conductive polymers such as polyacetylene, carbon whiskers, graphite whiskers, titanium carbide whiskers, conductive potassium titanate whiskers, conductive barium titanate whiskers, conductive titanium oxide whiskers, and conductive zinc oxide whiskers. All It is. The blending amount of the electronic conductive agent is preferably in the range of 0.5 to 50 parts by mass, more preferably in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the elastomer.

  Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified fatty acid dimethylethylammonium, perchlorate, chlorate, hydrochloride, bromate, and the like. Ammonium salts such as salts, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, sulfonates; alkaline metals such as lithium, sodium, potassium, calcium, magnesium, alkaline earth metals Examples include perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, trifluoromethyl sulfate, and sulfonate. The compounding amount of the ionic conductive agent is preferably in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.05 to 5 parts by mass with respect to 100 parts by mass of the elastomer. The said electrically conductive agent may be used individually by 1 type, may be used in combination of 2 or more type, and may combine an electronic conductive agent and an ionic conductive agent.

The elastic layer 3 has a resistance value of preferably 10 ³ to 10 ⁸ Ωcm, and more preferably 10 ⁴ to 10 ⁷ Ωcm, by blending the conductive agent. If the resistance value of the elastic layer 3 is less than 10 ³ Ωcm, the charge may leak to the photosensitive drum or the developing roller may be destroyed by voltage. If the resistance value exceeds 10 ⁸ Ωcm, the developing bias causes a voltage drop, A normal image density may not be obtained, and a ground fog is likely to occur.

  The elastic layer 3 may contain a crosslinking agent such as an organic peroxide and a vulcanizing agent such as sulfur in order to make the elastomer into a rubbery material as necessary. Sulfur accelerators, vulcanization accelerators, vulcanization retarders, and the like may be included. The elastic layer 3 is further used for rubber such as a filler, a peptizer, a foaming agent, a plasticizer, a softener, a tackifier, an anti-tacking agent, a separating agent, a release agent, an extender, and a coloring agent. You may contain a compounding agent.

  The hardness of the elastic layer 3 is not particularly limited, but is preferably 80 degrees or less, particularly 40 to 70 degrees in terms of Asker C hardness. In this case, if the hardness exceeds 80 degrees, the contact area with the photosensitive drum or the like becomes small, and there is a possibility that good development cannot be performed. Further, the toner is damaged, and the toner adheres to the photosensitive member or the layered blade. On the other hand, if the hardness is too low, the frictional force with the photoconductor and the layered blade increases, which may cause image defects such as jitter. In addition, since the elastic layer 3 is used in contact with a photoreceptor or a layered blade, even when the hardness is set to a low hardness, it is preferable to make the compression set as small as possible, specifically 20%. The following is preferable.

  As the resin for forming the coating layer 5 of the developing roller 1, a crosslinkable resin is used, but there is no particular limitation as long as it is a crosslinkable resin, and it is non-staining to an image forming body such as a photosensitive drum. Any material that does not adhere to each other is acceptable. Here, the crosslinkable resin refers to a resin that is self-crosslinked by heat, catalyst, air (oxygen), moisture (water), electron beam, or the like, or a resin that is crosslinked by a reaction with a crosslinking 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, and the like. Fluorine resin, polyamide resin, acrylic urethane resin, alkyd resin, phenol resin, melamine resin, silicone resin, polyurethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, polyether resin, amino resin, urea resin, Examples include acrylic resins, acrylic-modified silicone resins, styrene-butadiene resins, and mixtures thereof. Mixtures of these with other resins can also be used. Of these crosslinkable resins, polyurethane resins are preferred.

  Examples of the catalyst used for crosslinking these crosslinkable resins include radical catalysts such as peroxides and azo compounds, acid catalysts, basic catalysts, and the like. In addition, as the crosslinking agent, reactive groups 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, unsaturated group, etc. A compound having two or more molecules in one molecule and having a molecular weight of 1000 or less, preferably 500 or less, such as a polyol compound, a polyisocyanate compound, a polyaldehyde compound, a polyamine compound, and a polyepoxy compound. Further, the coating layer 5 is further added with various additives such as a charge control agent, a lubricant, and other resins for the purpose of improving the charging ability to the toner, reducing the frictional force with other members and imparting conductivity. An agent can be blended.

  The covering layer 5 can be blended with a conductive agent for the purpose of controlling its conductivity, and examples of the conductive agent are the same as those exemplified as the conductive agent used for the elastic layer 3. be able to.

  The method for forming the coating layer 5 is preferably a method in which a paint containing each component constituting the coating layer 5 is prepared, and the paint is applied on the elastic layer by a dipping method, a spray method, or a roll coating method and then dried. Used. Here, in the present invention, it is preferable to form the coating layer 5 by leaving the paint at room temperature and normal humidity for 24 hours or more and then applying the paint to the outer peripheral surface of the elastic layer. In this way, by leaving the paint at room temperature and normal humidity for 24 hours or more, it is possible to obtain the developing roller 1 having a surface having the above-mentioned specular gloss, and the toner transport amount of the obtained developing roller 1 is set appropriately. It can be within the range.

  Solvents used for the preparation of the coating material for forming the coating layer 5 include alcohol solvents such as methanol, ethanol, isopropanol and butanol; ketone solvents such as acetone, methyl ethyl ketone and cyclohexane; aromatics such as toluene and xylene Aliphatic hydrocarbon solvents such as hexane; aliphatic hydrocarbon solvents such as cyclohexane; ester solvents such as ethyl acetate; ether solvents such as isopropyl ether and tetrahydrofuran; dimethylsulfamide, etc. Amide solvents; halogenated hydrocarbon solvents such as chloroform and dichloroethane and the like, or mixed solvents thereof are preferably used. Such a solvent may be appropriately selected according to the solubility of the resin used, and is not particularly limited.

  The thickness of the coating layer 5 is not particularly limited, but is preferably 1 to 50 μm, and more preferably 5 to 10 μm. If the thickness of the coating layer 5 is less than 1 μm, local discharge may occur and white horizontal lines may be easily generated in the image. If the thickness exceeds 50 μm, the surface of the developing roller 1 becomes hard, and the toner In some cases, the toner is fixed to the photosensitive drum or the stratified blade due to damage, resulting in an image defect.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to the following Example at all.

(Examples 1-3 and Comparative Examples 1-4)
After mixing the base polymer of the following composition, a curing agent is added, cast into a mold in which the shaft 2 has been placed in advance, and cured at 90 ° C. for 8 hours, and elastic on the outer periphery of the shaft 2 Layer 3 was formed. After removing the elastic layer 3, the surface 3f was ground under different conditions.

Base polymer composition Polyether polyol (trade name: SBU 0610) 100 parts by weight Silicone surfactant (trade name: BY16-201) 5 parts by weight dibutyltin dilaurate 0.01 parts by weight acetylene black 3 parts by weight
Curing agent Urethane modified MDI (trade name: Sumidur PF) 17.5 parts by mass

  Next, 100 parts by mass of urethane resin (trade name: Die-Pla Coat SO4748, manufactured by Dainichi Seika), 10 parts by mass of isocyanate curing agent (trade name: EN-2, manufactured by Dainichi Seika), silica filler (trade name: Nipsil SS) (-20, manufactured by Nippon Silica) 20 parts by mass was mixed to prepare a coating layer-forming coating material, which was then left at room temperature and normal humidity for the time shown in Table 1. After being allowed to stand, the paint was diluted by appropriately using a solvent so as to have a predetermined viscosity shown in Table 1. This was dipped on the elastic layer 3 to form a resin coating film and cured at 110 ° C. for 4 hours to form a coating layer 5. As described above, the developing rollers of the respective examples and comparative examples were produced.

The following characteristic tests were conducted on the developing rollers of the above Examples and Comparative Examples. The results are shown in Table 1.
(1) Polishing conditions The surface of the roller body was polished under the following conditions using the polishing apparatus shown in FIG.
(a) Polishing equipment
(b) Grinding wheel: CG # 80 [JISR6001], Abrasive material: Silicon carbide (manufactured by Teiken Co., Ltd.)
(In accordance with [JISR6210] for each grinding wheel,
Measures the depth of biting with a diameter of 8 mm or a diameter of 12 mm. )
(c) Roller body rotation speed: 150rpm
(d) Grinding wheel rotation speed: 2600 rpm
(2) Surface glossiness (Gs)
As for the surface glossiness of each roller body, the vertexes when held in the state shown in FIG. 4 (a) so that there is no deviation in the axial direction and the circumferential direction of the roller body are shown in FIG. 4 (b). 6 points were measured at an incident angle of 85 ° along the axial direction in accordance with [JIS Z8741] using a “No. 4601 Gardner Haze Gross Meter” (manufactured by BYK Gardner). The average of these 6 points The value was determined.
(3) Surface roughness (Rz)
For the surface of each roller body, a surface roughness meter Surfcom 590A (manufactured by Tokyo Seimitsu Co., Ltd.) was used, and the measurement length was 2.4 mm in the direction perpendicular to the axial direction (the rotation direction of the roller body), and the measurement speed was 0.8. An average of 10 points of roughness [JIS B0601] was determined by averaging 300 measured values at 3 mm / sec and a cutoff wavelength of 0.8 mm so that there was no deviation in the axial direction and circumferential direction of the roller body.
(4) Image quality evaluation (cover)
Each developing roller had an outer diameter of 20.00 ± 0.05 mm, and an outer diameter runout measured with the metal shaft held was 0.03 mm. As the toner, positively charged, non-magnetic one component, polymerized toner was used, and silicone rubber was used as a material for the cleaning blade. Furthermore, “BUSSINESS MULTIPURPOSE 4200 PAPER” (manufactured by XEROX) was used as the paper, and characters were printed by adjusting the number of characters so that the printing condition was a predetermined occupied area% with respect to the paper area. The maximum number of printed sheets is 14000 with a 1% print density. When “fogging” occurs between the 0th and 8000th sheets, “variation” occurs. ".

  As shown in Table 1, the grindstone satisfies the condition that the particle size is in the range of # 80 to # 100 and the biting depth is in the range of 0.60 mm to 0.81 mm when using the 8 mm diameter bit or the 12 mm diameter bit. In the case of each of Examples 1 to 3 where polishing was carried out using the film, it was confirmed that good image quality could be obtained if a coating layer was formed and used as a developing roller.

  On the other hand, the condition that the particle size is in the range of # 80 to # 100 and the biting depth is in the range of 0.60 mm to 0.81 mm when using a bit having a diameter of 8 mm or a bit of 12 mm is not satisfied. In each of Comparative Examples 1 to 4 where polishing was performed using a grindstone, it was confirmed that variation in image quality occurred when a coating layer was formed and used as a developing roller.

  5A and 5B are graphs obtained by extracting Examples 1 and 3 and Comparative Examples 3 and 4 for the particle size # 80 from [Table 1].

  The present invention can also be applied to a method of manufacturing a developing roller that supplies toner to an image formed body made of paper.

1 is a schematic cross-sectional view showing an image forming apparatus employing a developing roller manufactured according to the present invention. (a), (b) is the perspective view and sectional drawing which show the developing roller manufactured according to this invention, respectively. It is a schematic diagram which illustrates the implementation condition in grind | polishing a roller main body. (a), (b) is the perspective view and schematic diagram which respectively illustrate the measuring method of specular glossiness. (a), (b) is the figure which extracted and graphed Example 1, 2 and Comparative Examples 3, 4, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Shaft 3 Elastic layer 4 Roller body 5 Covering layer

Claims (3)

In manufacturing a developing roller used for supplying toner,
The surface of the main body of the developing roller is polished with a grindstone that satisfies the following conditions,
Next, a method for producing a developing roller, wherein a coating layer for carrying toner is formed on the polished surface.
Grinding wheel particle size: in the range of # 80 to # 100 Depth of penetration indicating the degree of particle bonding of the grinding wheel: Depth of penetration in the range of 0.60 mm to 0.81 mm (biting depth when using a bit with a diameter of 8 mm or a bit with a diameter of 12 mm )   2. The method for producing a developing roller according to claim 1, wherein when the main body of the developing roller is polished, the grindstone is rotated in a range of 2000 rpm to 3000 rpm, and the main body of the developing roller is rotated in a range of 30 rpm to 150 rpm. .   The method for producing a developing roller according to claim 1 or 2, wherein a feeding speed is 2.5 mm / min to 10 mm / min when the grindstone is brought into contact with the main body of the developing roller.