JP2011033838A - Toner supply roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner supply roll which has low hardness and is excellent in conductive characteristics and durability. <P>SOLUTION: The toner supply roll 10 includes a conductive shaft 11 and a non-conductive foamed elastic layer 12 provided on the circumference of the shaft 11. A conductive layer 13, which contains a conductive agent and whose thickness is 0.5 to 1.5 mm, is provided at the circumference and end of the foamed elastic layer 12, and the average open cell diameter of the surface of the toner supply roll is 100 to 800 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner supply roll used in an image forming apparatus such as an electrophotographic copying machine and printer, or a toner jet copying machine and printer.

  A toner supply roll of an image forming apparatus such as a copying machine or a printer is required to have a low hardness as the speed of the apparatus increases. Therefore, a toner supply roll using a foamed elastic body such as polyurethane foam has been proposed, and the hardness (contact pressure) and the coefficient of friction are adjusted according to the blending ratio and expansion ratio of the foamed elastic body. However, when a foamed elastic body is formed by blending a conductive agent, there is a problem that the viscosity of the material increases and it is difficult to obtain a highly foamed foamed elastic body.

  Further, a toner supply roll has been proposed in which a coating is formed on the surface of a polyurethane foam to form a film (see Patent Document 1). However, there has been a problem that sufficient conductivity cannot be obtained and the coat layer is easily peeled off.

Japanese Patent No. 2002-236414

  In view of such circumstances, it is an object of the present invention to provide a toner supply roll having low hardness and excellent conductivity characteristics and durability.

  A first aspect of the present invention for solving the above problem is a toner supply roll comprising a conductive shaft and a non-conductive foam elastic layer provided on the outer periphery of the shaft, A conductive layer containing a conductive agent and having a thickness of 0.5 to 1.5 mm is provided on the outer periphery and the end, and the average open cell diameter on the surface of the toner supply roll is 100 to 800 μm. In the toner supply roll.

  According to a second aspect of the present invention, there is provided the toner supply roll according to the first aspect, wherein the conductive agent is at least one of an electronic conductive agent and an ionic conductive agent. .

  According to a third aspect of the present invention, in the toner supply roll according to the first or second aspect, the conductive layer is formed by applying a conductive paint containing a conductive agent. The conductive paint is in a toner supply roll including an organic solvent and at least one of rubber and resin soluble in the organic solvent.

  According to a fourth aspect of the present invention, in the toner supply roll according to the third aspect, the organic solvent swells the foamed elastic layer.

  According to a fifth aspect of the present invention, in the toner supply roll according to the third or fourth aspect, the conductive paint includes at least one selected from urethane, silicone, acrylic, and nylon. The toner supply roll.

  According to a sixth aspect of the present invention, in the toner supply roll according to any one of the third to fifth aspects, the conductive paint contains an additive.

  According to a seventh aspect of the present invention, in the toner supply roll according to the sixth aspect, the additive is a fluorine compound, silicone, or silica.

  According to an eighth aspect of the present invention, in the toner supply roll according to the first or second aspect, the conductive layer includes a surface treatment liquid containing at least an isocyanate component and an organic solvent in a surface layer portion of the foamed elastic layer. The toner supply roll is formed by impregnation.

  According to a ninth aspect of the present invention, in the toner supply roll according to any one of the first to eighth aspects, the toner supply roll has the foam elasticity after the foamed elastic layer is formed on an outer periphery of the shaft. The toner supply roll is obtained by forming the conductive layer on the outer periphery and end of the layer.

According to a tenth aspect of the present invention, in the toner supply roll according to any one of the first to ninth aspects, the foamed elastic layer is measured under an NN environment (23 ° C., 55% RH) at an applied voltage of 100V. The toner supply roll has an electrical resistance value of 1.0 × 10 ⁹ Ω to 1.0 × 10 ¹⁶ Ω.

An eleventh aspect of the present invention is the toner supply roll according to any one of the first to tenth aspects, wherein the toner supply roll is measured at an applied voltage of 100 V under an NN environment (23 ° C., 55% RH). The toner supply roll has an electrical resistance value of less than 1.0 × 10 ⁸ Ω.

  According to the present invention, it is possible to provide a toner supply roll having desired conductive characteristics and excellent durability without peeling while maintaining the low hardness of the foamed elastic body.

FIG. 3 is a cross-sectional view of a toner supply roll of the present invention. 10 is a diagram for explaining a measurement method of Test Example 3. FIG. 3 is an enlarged cross-sectional photograph of a toner supply roll of the present invention.

  Hereinafter, the toner supply roll of the present invention will be described in detail. FIG. 1 is a cross-sectional view of the toner supply roll of the present invention.

  As shown in FIG. 1, the toner supply roll 10 has a conductive shaft 11 and a non-conductive foamed elastic layer 12 provided on the outer periphery of the shaft 11. Is provided with a conductive layer 13 containing a conductive agent and having a thickness of 0.5 to 1.5 mm. The average open cell diameter on the surface of the toner supply roll 10 is 100 to 800 μm.

  Thus, by providing the conductive layer 13 having a predetermined thickness on the outer periphery and the end of the foamed elastic layer 12, the shaft 11 and the conductive layer 13 are electrically connected, and the toner supply roll 10 is made conductive. It will be excellent. The toner supply roll 10 of the present invention can sufficiently ensure conductivity, so that no image defect occurs during image formation. In addition, when the conductive layer 13 is not formed in the edge part of the foamed elastic layer 12, sufficient electroconductivity cannot be ensured.

  As described above, the conductive layer 13 according to the present invention has a thickness of 0.5 to 1.5 mm. Here, the thickness of the conductive layer 13 refers to the width of the region where the conductive agent is present. The conductive layer 13 is formed without blocking the cell opening on the surface of the foamed elastic layer 12. That is, the conductive layer 13 is not formed so as to cover and cover the cell opening on the surface of the foamed elastic layer 12, but to hold the cell opening on the surface of the foamed elastic layer 12 as it is. It is formed along the inner surface. As a result, the toner supply roll 10 is in a state in which cells are opened on the surface, and has excellent toner scraping performance. Further, since the cells of the foamed elastic layer 12 are held, characteristics such as low hardness and low specific gravity of the foamed elastic layer 12 can be maintained, and the conductive layer having a thickness of 0.5 to 1.5 mm can be maintained. By forming the layer 13, it becomes excellent in electroconductivity and abrasion resistance. That is, the toner supply roll 10 has a low hardness and an improved conductivity and wear resistance while ensuring a nip.

  If the thickness of the conductive layer 13 is less than 0.5 mm, sufficient conductivity cannot be ensured. On the other hand, if the thickness is larger than 1.5 mm, the hardness of the toner supply roll 10 is increased, and filming is likely to occur on the surface of the developing roll, or the toner is deteriorated. Further, the toner supply roll 10 may be deformed when used for a long time.

  The conductive layer 13 may be formed by applying a conductive paint containing a conductive agent, or impregnating the surface layer of the foamed elastic layer 12 with a surface treatment liquid containing a conductive agent and an isocyanate compound. There is a method of forming by. By these methods, the conductive agent can be fixed to the outer periphery and the end of the foamed elastic layer 12 to form the conductive layer 13. Further, by forming the conductive layer 13 on the outer periphery of the foamed elastic layer 12, the toner supply roll 10 can be adjusted to a desired coefficient of friction.

  As the conductive agent, an electronic conductivity imparting agent such as carbon black or metal powder, an ionic conductivity imparting agent, or a mixture of both can be used. Although carbon black has various properties, it is preferable to use carbon fine powder. Examples of the ion conductivity-imparting agent include organic salts, inorganic salts, metal complexes, ionic liquids and the like. Examples of organic salts and inorganic salts include lithium perchlorate, quaternary ammonium salts, and sodium trifluoride acetate. Moreover, as a metal complex, halogenated ferric-ethylene glycol etc. can be mentioned, Specifically, what was described in the patent 3655364 can be mentioned. On the other hand, the ionic liquid is a molten salt that is liquid at room temperature, and is also called a room temperature molten salt, and particularly refers to a melting point of 70 ° C. or lower, preferably 30 ° C. or lower. Specific examples include those described in JP-A No. 2003-202722.

  When forming the conductive layer 13 by applying a conductive paint containing a conductive agent, apply a conductive paint containing an organic solvent and at least one of rubber and resin soluble in the organic solvent, The conductive layer 13 is formed by drying and curing. Sufficient conductivity can be ensured by using rubber or resin as a binder and fixing the conductive agent on the outer periphery and the end of the foamed elastic layer 12. When the conductive layer 13 is formed by applying a conductive paint, the conductive layer 13 is formed so as to coat the surface of the foamed elastic layer 12 and without blocking the cell opening on the surface of the foamed elastic layer 12. The That is, the conductive layer 13 includes a portion that coats the surface and a portion that is formed along the inner surface of the cell.

  At least one of rubber and resin may be used and may be used in combination. The rubber and resin need to be soluble in an organic solvent, and are preferably stretched after drying so as to withstand deformation during use. Moreover, it is preferable to select a rubber and a resin that have an SP value close to that of the rubber base to be used. By selecting a material having a close SP value, it is easy to impregnate a foamed elastic layer made of a rubber base material, a relatively thick conductive layer 13 can be formed, and adhesion is improved. As a result, a toner supply roll having higher durability can be obtained. Examples of the resin include acrylic resin, amide resin, fluororesin, polyvinyl chloride resin, polyester resin, and polystyrene resin. Examples of rubber include urethane rubber, silicone rubber, and acrylic rubber. In addition, nylon is mentioned as an amide resin. Silicone rubber, urethane rubber, and acrylic rubber are particularly preferable because they are excellent in flexibility and adhesion to a rubber base material.

  The conductive paint may contain an additive. Examples of the additive include a fluorine compound, silicone, and silica. By blending the additive, toner releasability on the surface of the toner supply roll 10 is improved.

  Any organic solvent may be used as long as it can swell the foamed elastic layer, dissolve the paint, and disperse the conductive agent. Ethyl acetate for foamed elastic layers made of urethane rubber, epichlorohydrin rubber, acrylonitrile butadiene rubber (NBR), natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, chlorinated polyethylene, or acrylic rubber substrate Butyl acetate, methyl ethyl ketone (MEK), methyl ethyl isobutyl ketone (MIBK), toluene and the like are preferably used, and ethyl acetate, butyl acetate, toluene and the like are suitably used for the foamed elastic layer made of the silicone rubber base material. Toluene or the like is preferably used for the foamed elastic layer made of an EPDM base material.

The conductive paint is preferably a blend of 0.5 to 50 parts by mass of the conductive agent with respect to 100 parts by mass of the resin or rubber. Thereby, for example, the electrical resistance value of the conductive paint is set to be less than 1.0 × 10 ³ Ω.

  Examples of the method for applying the conductive paint include a spray coating method, a roll coating method, and a dip coating method using a conductive paint on the foamed elastic layer 12, and the spray coating method and the roll coating method are preferable. At this time, the type and blending amount of the conductive paint rubber and resin, the coating amount, the coating air pressure, the number of coatings, the roll pressing amount, etc. are adjusted so that the thickness of the conductive layer 13 is 0.5 to 1.5 mm. Prepare as appropriate.

  When the conductive layer 13 is formed by impregnating the surface treatment liquid containing the conductive agent and the isocyanate compound into the surface layer portion of the foamed elastic layer 12, the foamed elastic layer 12 is immersed in the surface treatment liquid or the foamed elastic layer 12. The conductive layer 13 is formed by applying a surface treatment liquid to the substrate by spray coating or the like and drying and curing it. In this case, the conductive layer 13 is formed integrally with the foamed elastic layer 12. Specifically, when the organic solvent in the surface treatment liquid permeates into the foamed elastic layer 12, the foamed elastic layer 12 slightly swells to generate fine grooves, and the fine grooves have a fine groove in the surface treatment liquid. At least an isocyanate component and a conductive agent are filled to form a conductive layer 13 integral with the foamed elastic layer 12.

  Here, the surface treatment liquid is obtained by dissolving at least an isocyanate component in an organic solvent.

  As isocyanate components contained in the surface treatment liquid, 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI) and Mention may be made of isocyanate compounds such as 3,3-dimethyldiphenyl-4,4′-diisocyanate (TODI), and the aforementioned multimers and modified products. Furthermore, the prepolymer which consists of a polyol and isocyanate can be mentioned.

It is preferable that the surface treatment liquid is a mixture of 0.5 to 50 parts by mass of the conductive agent with respect to 100 parts by mass of the isocyanate component. Thereby, for example, the electrical resistance value of the conductive paint is set to be less than 1.0 × 10 ³ Ω.

  The surface treatment liquid may contain a polyether polymer. Here, the polyether polymer is preferably soluble in an organic solvent, and preferably has active hydrogen and can be chemically bonded by reacting with an isocyanate compound.

  Examples of suitable polyether polymers having active hydrogen include epichlorohydrin rubber. The epichlorohydrin rubber here refers to an unvulcanized state. Epichlorohydrin rubber is preferable because it can impart elasticity to the conductive layer as well as conductivity. The epichlorohydrin rubber has an active hydrogen (hydroxyl group) at the terminal, but preferably has a unit having an active hydrogen such as a hydroxyl group or an allyl group. Examples of the epichlorohydrin rubber include an epichlorohydrin homopolymer, an epichlorohydrin-ethylene oxide copolymer, an epichlorohydrin-allyl glycidyl ether copolymer, an epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer and a derivative thereof. it can.

  Examples of other suitable polyether polymers having active hydrogen include polymers having a hydroxyl group or an allyl group, such as polyols and glycols. Such a polyether polymer preferably has only one terminal rather than one having active hydrogen groups at both terminals. Moreover, it is preferable that a number average molecular weight is 300-1000. This is because elasticity can be imparted to the conductive layer. Examples of such polyether polymers include polyalkylene glycol monomethyl ether, polyalkylene glycol dimethyl ether, allylated polyether, polyalkylene glycol diol, polyalkylene glycol triol, and the like.

  By adding a polyether-based polymer to the surface treatment liquid in this way, the flexibility and strength of the conductive layer are improved. As a result, the surface of the desired roll is worn or the surface of the photoreceptor or the like that is in contact is damaged. There is no risk of being lost.

  Further, the surface treatment liquid may contain a polymer selected from an acrylic fluorine polymer and an acrylic silicone polymer.

  The acrylic fluorine-based polymer and acrylic silicone-based polymer used in the surface treatment liquid of the present invention are soluble in a predetermined solvent and can be chemically bonded by reacting with an isocyanate compound. The acrylic fluorine-based polymer is, for example, a solvent-soluble fluorine-based polymer having a hydroxyl group, an alkyl group, or a carboxyl group, and examples thereof include block copolymers of acrylic acid esters and alkyl fluorinated acrylates and derivatives thereof. . The acrylic silicone polymer is a solvent-soluble silicone polymer, and examples thereof include block copolymers of acrylic acid esters and acrylic acid siloxane esters, and derivatives thereof.

  Moreover, it is preferable that the acrylic fluorine-based polymer and the acrylic silicone-based polymer in the surface treatment liquid have a total amount of the acrylic fluorine-based polymer and the acrylic silicone-based polymer of 10 to 70% by mass with respect to the isocyanate component. When the amount is less than 10% by mass, functions such as releasability are hardly exhibited. On the other hand, when the polymer amount is more than 70% by mass, there are problems that the electric resistance value of the toner supply roll is increased, and there is a problem that an effective conductive layer cannot be formed due to relatively less isocyanate component.

  Further, the surface treatment liquid contains an isocyanate component and an organic solvent that dissolves the polyether-based polymer, the acrylic fluorine-based polymer, and the acrylic silicone-based polymer that are included as necessary. Although it does not specifically limit as an organic solvent, What is necessary is just to use organic solvents, such as ethyl acetate, methyl ethyl ketone (MEK), and toluene.

  As described above, the conductive layer 13 is impregnated into the surface layer portion of the foamed elastic layer 12 and integrally provided by impregnating and curing the surface treatment liquid on the surface layer portion of the foamed elastic layer 12 to provide the conductive layer 13. It is done. In such a conductive layer 13, the isocyanate component mainly serves as a binder, and the conductive agent is fixed to the outer periphery and the end of the foamed elastic layer 12 by being cured, thereby ensuring sufficient conductivity. .

  The toner supply roll 10 of the present invention is preferably obtained by forming the foamed elastic layer 12 on the outer periphery of the shaft 11 and then forming the conductive layer 13 on the outer periphery and the end of the foamed elastic layer 12. Thereby, the shaft 11 and the conductive layer 13 formed on the outer periphery and end of the foamed elastic layer 12 are reliably electrically connected.

  The toner supply roll 10 has an average open cell diameter of 100 to 800 μm. The average opening cell diameter here is an average value of the opening diameters of the cells opened on the surface of the toner supply roll. If the average open cell diameter is too small, the toner cannot be taken in and the transport amount is reduced. Further, when the cell diameter is small, there is a possibility that the characteristics of low hardness and low specific gravity cannot be obtained. On the other hand, if the average open cell diameter is too large, the toner scraping effect cannot be obtained sufficiently and the roll surface becomes poor.

  The nonconductive foamed elastic layer 12 is a foamed rubber base material. The rubber substrate is not particularly limited, and urethane rubber, epichlorohydrin rubber, acrylonitrile butadiene rubber (NBR), natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, fluoro rubber, chlorinated polyethylene, acrylic rubber, silicone Examples thereof include rubber and EPDM. These rubber base materials may be used in combination, and the type and combination are appropriately selected according to the application and purpose. The foamed elastic layer 12 is formed by mixing and foaming the above-described rubber base material, and may be formed by mixing a foaming agent, a foaming aid, a vulcanizing agent, a vulcanization accelerator, a filler and the like. Good. Although specific gravity is not specifically limited, It is preferable to exist in the range of 0.015-0.3.

The non-conductive foamed elastic layer 12 does not contain a conductive agent. For example, the electrical resistance value measured at an applied voltage of 100 V under an NN environment (23 ° C., 55% RH) is 1.0 ×. 10 ⁹ Ω to 1.0 × 10 ¹⁶ Ω. The foamed elastic layer made of urethane is about 1.0 × 10 ⁹ Ω to 1.0 × 10 ¹¹ Ω, and the foamed elastic layer made of EPDM is about 1.0 × 10 ¹⁴ Ω to 1.0 × 10 ¹⁶ Ω. Become. Since the non-conductive foamed elastic layer 12 does not contain a conductive agent, the non-conductive foamed elastic layer 12 can easily be highly foamed, and can have a low hardness and a low specific gravity.

  The foamed elastic layer 12 may be open cells or closed cells, but open cells are preferable when the conductive layer is formed using a conductive paint. This is because, since the foamed elastic layer 12 is an open cell, the conductive paint can enter the foamed elastic layer 12 through the cells, and the conductive layer 13 having a desired thickness can be easily formed.

The toner supply roll 10 according to the present invention preferably has an electrical resistance value measured under an NN environment (23 ° C., 55% RH) at an applied voltage of 100 V of less than 1.0 × 10 ⁸ Ω, more preferably. 1.0 × 10 ³ Ω to 1.0 × 10 ⁶ Ω. Thereby, the toner can be suitably held.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to this.

Example 1
<Manufacture of rolls>
By slicing a urethane sponge with a specific gravity of 0.078 and a hardness of 353N (JISK6400), making a hole through the shaft in the center, inserting a shaft with a diameter of 6 mm treated with adhesive on the surface, and then heating and polishing the surface A roll member having a diameter of 15.5 mm and a width of 220 mm of the foamed elastic layer portion was obtained.

The roll had an electric resistance value of 1.8 × 10 ¹⁰ Ω and an average open cell diameter of 290 μm.

<Preparation of conductive paint>
5 parts by mass of carbon black (Ketjen Black EC300J; made by Lion) were dispersed and mixed in a solution in which 20 parts by mass of urethane resin (Nipporan 5199; made by Nippon Polyurethane) was dissolved in 100 parts by mass of methyl ethyl ketone.

<Roll processing>
In Example 1, a conductive layer having a thickness of 0.5 mm was formed by applying a conductive paint on the outer periphery and end of the roll member by spraying and heating in an oven maintained at 120 ° C. for 1 hour. A toner supply roll was used.

The electric resistance value of the roll after coating was 3.5 × 10 ⁷ Ω, and the average open cell diameter was 280 μm.

(Example 2)
<Manufacture of rolls>
Slicing urethane sponge with specific gravity of 0.017 and hardness of 80N, drilling the shaft through the shaft in the center, inserting the shaft treated with adhesive on the surface, heating and surface polishing to obtain the target roll member It was.

The roll had an electric resistance value of 4.2 × 10 ⁹ Ω and an average open cell diameter of 760 μm.

<Preparation of conductive paint>
100 parts by mass of condensation reaction type silicone rubber (YSR3022; manufactured by Momentive Performance Materials Japan LLC), 446 parts by mass of toluene, 4 parts by mass of catalyst (YC6831; manufactured by Momentive Performance Materials Japan LLC), Adhesion improver (XC9603; manufactured by Momentive Performance Materials Japan GK) 50 parts by mass and 30 parts by mass of carbon black (acetylene black; manufactured by Denki Kagaku Co., Ltd.) were added, mixed and dissolved, and the conductive paint of Example 2 was added. Produced.

<Roll processing>
Conductive paint is applied to the outer periphery and end of the roll member by spraying, applying air pressure, and heating for 5 minutes in an oven maintained at 120 ° C. to form a conductive layer with a thickness of 1.0 mm This was used as the toner supply roll of Example 2.

The electric resistance value of the roll after coating was 1.4 × 10 ⁴ Ω, and the average open cell diameter was 740 μm.

(Example 3)
<Manufacture of rolls>
Epichlorohydrin rubber kneaded with a 10-inch roll was extruded using a shaft with a cross-head extruder to form a roll shape. After molding, a roll-shaped product was put into an electric furnace and vulcanized and foamed to obtain a target roll member.

The specific gravity was 0.250, the electrical resistance value of the roll was 5.8 × 10 ⁹ Ω, and the average open cell diameter was 130 μm.

<Preparation of conductive paint>
20 parts by mass of an acrylic polymer (Acridic A-801-P; manufactured by DIC), 4 parts by mass of an isocyanate compound (MDI; manufactured by Dainippon Ink & Co.), 100 parts by mass of butyl acetate, carbon black (acetylene black; electrochemical) 5 parts by mass) were added, mixed and dissolved to prepare the conductive paint of Example 3.

<Roll processing>
The roll member is transferred and applied to the outer periphery and end of the roll member by contacting with a roll impregnated with conductive paint, and heated in an oven maintained at 120 ° C. for 1 hour to form a conductive layer having a thickness of 1.5 mm. The formed toner was used as a toner supply roll of Example 3.

The electric resistance value of the roll after coating was 7.1 × 10 ³ Ω, and the average open cell diameter was 130 μm.

Example 4
Using the roll member of Example 1, a conductive roll of Example 4 was obtained in the same manner except that lithium perchlorate was added instead of acetylene black in the conductive paint of Example 1.

The electric resistance value of the roll after coating was 4.9 × 10 ⁶ Ω, and the average open cell diameter was 300 μm.

(Example 5)
<Preparation of conductive paint>
Example 5 By mixing 100 parts by mass of N-methoxymethylated nylon (Torresin EF30T manufactured by Teikoku Kagaku) and 20 parts by mass of carbon black (Ketjen Black EC300J; manufactured by Lion) with 400 parts by mass of MEK, Example 5 A conductive paint was prepared.

<Roll processing>
The outer periphery and the end of the roll member of Example 2 were transferred and applied by bringing them into contact with the roll impregnated with the conductive paint of Example 5, and heated in an oven maintained at 120 ° C. for 1 hour. A toner supply roll of Example 5 was formed with a conductive layer having a thickness of 1.0 mm.

The electric resistance value of the roll after coating was 4.2 × 10 ⁵ Ω, and the average open cell diameter was 770 μm.

(Example 6)
<Preparation of surface treatment solution>
1. 100 parts by mass of ethyl acetate, 7 parts by mass of isocyanate compound (MDI; manufactured by Dainippon Ink & Co.), 2 parts by mass of carbon black (acetylene black; manufactured by Electrochemical Co., Ltd.), acrylic fluoropolymer (Modiper F600; manufactured by Nippon Oil & Fats) 5 parts by mass, 1.5 parts by mass of acrylic silicone polymer (Modiper FS700; manufactured by NOF Corporation) and 1.0 part by mass of polyethylene glycol diallyl ether (molecular weight 450) were dispersed and mixed for 3 hours using a ball mill.

<Roll processing>
The electroconductive roll of Example 6 was obtained like Example 1 except having used said surface treatment liquid.

The electric resistance value of the roll after the surface treatment was 8.6 × 10 ⁶ Ω, and the average open cell diameter was 290 μm.

(Comparative Example 1)
<Roll processing>
A toner supply roll of Comparative Example 1 was obtained in the same manner as in Example 1 except that the coating amount was reduced and the thickness of the conductive layer was changed to 0.3 mm.

The electric resistance value of the roll after coating was 1.8 × 10 ⁹ Ω, and the average open cell diameter was 290 μm.

(Comparative Example 2)
<Roll processing>
A toner supply roll of Comparative Example 2 was obtained in the same manner as in Example 1 except that the number of times of application was increased to make the thickness of the conductive layer 1.8 mm.

The electric resistance value of the roll after coating was 2.2 × 10 ⁴ Ω, and the average open cell diameter was 280 μm.

(Comparative Example 3)
A conductive roll of Comparative Example 3 was obtained in the same manner as in Example 1 except that the conductive paint was not applied to the end of the roll member.

The electric resistance value of the roll after coating was 1.3 × 10 ¹⁰ Ω, and the average open cell diameter was 280 μm.

(Comparative Example 4)
Using the roll member and conductive paint of Example 1, the entire sponge was impregnated by dipping treatment, and then the treatment liquid was blown off by blowing air and heated in an oven maintained at 120 ° C. for 1 hour in the same manner. The roll member of Comparative Example 4 was obtained.

The electric resistance value of the roll after coating was 9.7 × 10 ³ Ω, and the average open cell diameter was 270 μm.

(Comparative Example 5)
<Preparation of conductive paint>
5 parts by mass of carbon black (acetylene black; manufactured by Electrochemical Co., Ltd.) was added and mixed and dispersed in 100 parts by mass of an aqueous urethane resin (Hydran WLS221; manufactured by DIC) to prepare a conductive paint of Comparative Example 5.

<Roll processing>
Comparison was made by applying a transfer coating by contacting a roll impregnated with the conductive paint of Comparative Example 5 and heating it in an oven maintained at 120 ° C. for 1 hour to form a conductive layer having a thickness of 0.3 mm. The toner supply roll of Example 5 was obtained.

The electric resistance value of the roll after coating was 7.7 × 10 ⁸ Ω, and the average open cell diameter was 750 μm.

(Comparative Example 6)
A conductive roll of Comparative Example 6 was obtained in the same manner as in Example 2 except that a sponge having a specific gravity of 0.014, a hardness of 30 N, and an average open cell diameter of 880 μm was used.

The electric resistance value of the roll after coating was 1.4 × 10 ⁴ Ω, and the average open cell diameter was 870 μm.

(Test Example 1) Measurement of average open cell diameter The diameter of the foam cell opened on the surface of the conductive foamed elastic body (outer periphery) was magnified 50 times with a microscope (VHX-100 manufactured by KEYENCE Inc.), and arbitrarily 50 cells. Was selected and the cell diameter was averaged to obtain an average open cell diameter.

(Test Example 2) Measurement of the thickness of the conductive layer The thickness of the region by coating was cut from a 40 mm portion from both ends of the roll and a sponge at the center of the roll so as to be parallel to the side surface, and the cross section was observed with a microscope. The distance from the surface to the portion where the conductive agent reached (black portion in FIG. 3) was measured, the average value was obtained, and the thickness of the conductive layer was obtained.

(Test example 3) Measurement of flare The flakes of each example and each comparative example were measured. Fle is a value obtained by subtracting the minimum value from the maximum value when the diameter is measured for one roll. The results are shown in Table 1.

(Test Example 4) Electrical Resistance Measurement Electrical resistance values were measured for the toner supply rolls of the examples and comparative examples. As shown in FIG. 2, the toner supply roll 10 is placed on the electrode member 40 made of a SUS304 plate, and a 100 g load is applied to both ends of the shaft 11. The resistance value was measured using ULTRA HIGH RESISTANCE METER R8340A (manufactured by Advantest Corporation) in an NN environment (23 ° C., 55% RH). The applied voltage at this time was DC-100V. The results are shown in Table 1.

(Test Example 5) Image Evaluation The toner supply rolls of the examples and comparative examples were mounted on a commercially available printer (C5800, manufactured by Oki Data Co., Ltd.), and solid under an NN environment (23 ° C., 55% RH). Image printing and an image printing test for ghost confirmation were performed, and the printed images were visually evaluated. The image evaluation was: ○: no blurring, ghost, or density difference was observed in the image, blurring: blurring was observed at the rear end of the image, ghost: ghosting was observed, density difference: solid image had a density difference Judgment was made by seeing. The results are shown in Table 1.

(Test example 6) Durability test The toner supply rolls of the examples and comparative examples were mounted on a commercially available printer (C5800, manufactured by Oki Data Co., Ltd.), and vertically aligned under an NN environment (23%, 55% RH). After printing 10,000 sheets of 10 mm × 197 mm wide, the adhesion between the foamed elastic layer 12 and the conductive layer 13 was confirmed. Specifically, after cleaning the toner, it was visually confirmed whether or not the foamed elastic layer 12 and the conductive layer 13 were peeled off. The results are shown in Table 1.

(Summary of results)
The toner supply rolls of Examples 1 to 6 having a thickness of the conductive layer of 0.5 to 1.5 mm had an electric resistance value of less than 1.0 × 10 ⁸ Ω, and the image evaluation was good. Moreover, peeling did not occur in the durability test, and the flare was very small.

On the other hand, the toner supply roll of Comparative Example 1 having a conductive layer thickness of 0.3 mm had an electric resistance value of 1.8 × 10 ⁹ Ω, and sufficient conductivity was not obtained. For this reason, the toner could not be supplied satisfactorily, and blurring occurred in image evaluation.

  The toner supply roll of Comparative Example 2 in which the thickness of the conductive layer was 1.8 mm had a difference in density in the image evaluation because of the large flare.

The toner supply roll of Comparative Example 3 in which no conductive layer was formed at the end portion had an electric resistance value of 1.3 × 10 ¹⁰ Ω, and sufficient conductivity was not obtained. For this reason, the toner could not be supplied satisfactorily, and blurring occurred in image evaluation.

  In the toner supply roll of Comparative Example 4 in which the conductive layer was formed on the entire foamed elastic layer, a difference in density occurred in the image evaluation because of the large flare. Further, the flare was larger than that of Comparative Example 2.

The conductive roll of Comparative Example 5 using water-based urethane as the paint and having a conductive layer thickness of 0.3 mm had an electrical resistance value of 7.7 × 10 ⁸ Ω, and sufficient conductivity was not obtained. For this reason, the toner could not be supplied satisfactorily, and blurring occurred in image evaluation. Further, due to insufficient adhesion, partial peeling occurred.

  The conductive roll of Comparative Example 6 having an average open cell diameter of the roll surface of 870 μm showed a ghost in the image evaluation because the toner on the developing roll could not be scraped off.

  As described above, the toner supply roll includes a conductive shaft and a non-conductive foamed elastic layer provided on the outer periphery of the shaft, and a conductive agent is contained in the outer periphery and the end of the foamed elastic layer. A toner supply roll having a conductive layer having a thickness of 0.5 to 1.5 mm and an average open cell diameter of 100 to 800 μm on the surface may be excellent in conductive characteristics and durability. all right.

DESCRIPTION OF SYMBOLS 10 Toner supply roll 11 Shaft 12 Elastic foam layer 13 Conductive layer 40 Electrode member

Claims (11)

A toner supply roll comprising a conductive shaft and a non-conductive foamed elastic layer provided on the outer periphery of the shaft, the outer periphery and the end of the foamed elastic layer having a thickness containing a conductive agent Is provided with a conductive layer of 0.5 to 1.5 mm, and an average open cell diameter on the surface of the toner supply roll is 100 to 800 μm. The toner supply roll according to claim 1, wherein the conductive agent is at least one of an electronic conductive agent and an ionic conductive agent. The toner supply roll according to claim 1, wherein the conductive layer is formed by applying a conductive paint containing a conductive agent, and the conductive paint includes an organic solvent and the organic solvent. And a toner supply roll comprising at least one of a rubber and a resin soluble in the toner. 4. The toner supply roll according to claim 3, wherein the organic solvent swells the foamed elastic layer. 5. The toner supply roll according to claim 3, wherein the conductive paint includes at least one selected from urethane, silicone, acrylic, and nylon. The toner supply roll according to any one of claims 3 to 5, wherein the conductive paint contains an additive. The toner supply roll according to claim 6, wherein the additive is a fluorine compound, silicone, or silica. 3. The toner supply roll according to claim 1, wherein the conductive layer is formed by impregnating a surface treatment liquid containing at least an isocyanate component and an organic solvent in a surface layer portion of the foamed elastic layer. A toner supply roll. 9. The toner supply roll according to claim 1, wherein the toner supply roll forms the foamed elastic layer on an outer periphery of the shaft, and then forms the conductive material on an outer periphery and an end of the foamed elastic layer. A toner supply roll obtained by forming a layer. 10. The toner supply roll according to claim 1, wherein the foamed elastic layer has an electric resistance value measured at an applied voltage of 100 V under an NN environment (23 ° C., 55% RH) of 1.0. 10. A toner supply roll, which is × 10 ⁹ Ω to 1.0 × 10 ¹⁶ Ω. 11. The toner supply roll according to claim 1, wherein the toner supply roll has an electrical resistance value of 1.0 when measured at an applied voltage of 100 V under an NN environment (23 ° C., 55% RH). A toner supply roll characterized by being less than × 10 ⁸ Ω.