JP5512167B2 - Charge-controlled urethane foam and toner conveying roller using the same - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge-controlled urethane foam and a toner transport roller (hereinafter, also simply referred to as “roller”) using the same, and more specifically, in an image forming apparatus such as a copying machine or a printer, Charge-controlled urethane foam used for a toner transport roller used for transporting toner (developer) to an image forming body and supplying toner to a developing roller that forms a visible image on the surface, and the same The present invention relates to a toner conveying roller.

  In general, as shown in FIG. 4, an image forming body 11 such as a photoconductor that holds an electrostatic latent image, and the image forming body are provided in a developing unit in an electrophotographic image forming apparatus such as a copying machine or a printer. A developing roller 12 that makes the electrostatic latent image visible by attaching toner 20 held on the surface in contact with the toner 11, and a toner transport roller (toner supply roller and unnecessary) for supplying toner to the developing roller 12 13 (including a cleaning roller for removing the toner), and a series of processes for conveying the toner 20 from the toner container 14 to the image forming body 11 via the toner conveying roller 13 and the developing roller 12. Then, image formation is performed. In the figure, reference numeral 15 denotes a transfer roller, 16 denotes a charging portion, 17 denotes an exposure portion, and 18 denotes a blade for scraping toner.

  Among these, the toner conveying roller 13 is provided with an adhesive layer on the outer periphery of the shaft from the viewpoint of not damaging the other party due to contact with the developing roller 12 and increasing the contact area of the roller to ensure grip. It is formed with a configuration in which a conductive elastic body such as urethane foam is supported. The functions required for the toner transport roller 13 include toner transportability, toner chargeability, toner scraping performance, and the like, and various measures have been taken to satisfy these functions.

  For example, the electrical resistance is lowered by a method of impregnating a polyurethane foam constituting the toner conveying roller 13 with a conductive treatment liquid such as conductive carbon black (see Patent Documents 1 to 3) or a method of kneading conductive carbon. In addition, the toner charge amount (Q / M) is decreased to increase the toner conveyance amount (M / A) so as not to cause the image blurring problem during the durability image evaluation.

  Further, without using a conductive material such as carbon, the surface of the toner conveyance roller 13 is provided with a concavo-convex shape to physically increase the toner conveyance amount (M / A), and the like, such as image blurring during durability image evaluation. A problem was not caused (see Patent Document 4).

  Furthermore, it has been known that toner transportability is improved by exposing a part of toner charging fine particles from the foamed elastic layer (see Patent Document 5).

JP-A-57-115433 (Claims etc.) JP 2002-319315 A (Claims etc.) JP 2003-215905 A (claims, etc.) JP-A-11-38749 (Claims etc.) JP 2008-116607 A (Claims etc.)

  However, since all of the methods described in Patent Documents 1 to 3 impregnate a urethane foam with a conductive material, it is possible to sufficiently prevent the influence of charging due to friction between the toner on the surface of the toner transport roller and the developing roller. As a result, the toner could not be transported sufficiently, resulting in problems such as image blurring during durability image evaluation.

  In addition, in the method of kneading carbon in urethane foam, there is no concern about image defects because there is no carbon detachment, but carbon is dispersed in the urethane foam molding process and molding with a mold is forced, and batch type small lot Production has led to increased costs.

  Furthermore, in the method described in Patent Document 4, it is necessary to use a toner transport roller having high resistance without using carbon, and to provide an uneven shape on the roller surface. Molding is common, and there are various cost-up factors associated with molding for each roller, such as mold cost, mold maintenance, mold release treatment (mold release agent, fluorine coating), etc. Existed.

  Furthermore, in the method described in Patent Document 5, after the adhesive is sprayed, the toner charging fine particles are adhered, and the toner charging fine particles are simply adhered to the surface to expose a part of the toner charging fine particles. Since the toner charging fine particles are detached, there are problems that the toner charging fine particles damage other members to cause an image defect, and that the image density becomes thin due to a decrease in the charge amount during durability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above problems, sufficiently prevent the influence of charging due to friction between the toner on the surface layer of the toner conveying roller and the developing roller, and obtain a stable and stable image at low cost. An object of the present invention is to provide a charge-controllable urethane foam and a toner conveying roller using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a charge-controlled urethane foam impregnated with a specific binder resin in the surface layer. It came to complete.

  That is, the charge-controlled urethane foam of the present invention is formed by impregnating the surface layer with a binder resin that is equal or on the positive side of the charge train with respect to the base urethane foam. The adhering amount of the impregnating liquid containing 9.0 to 14.9% by mass in dry mass, the base urethane foam is a base urethane foam impregnated with a carbon conductive material, and the binder resin Is characterized by containing a nylon resin.

  The toner conveying roller of the present invention is characterized in that the charge-controlled urethane foam is carried on the outer periphery of a shaft.

  In the toner transport roller of the present invention, it is preferable that the binder resin is on the positive side in the charging row with respect to the base urethane foam and is for negatively chargeable toner. In addition, it is preferable that the binder resin is on the positive side in the charge train with respect to the base urethane foam and is for positively chargeable toner.

  According to the present invention, the above configuration sufficiently prevents the influence of charging due to friction between the toner on the surface of the toner conveying roller and the developing roller, and can stably obtain a good image at low cost. It has become possible to realize a charge-controlled urethane foam and a toner conveying roller using the same.

FIG. 3 is a cross-sectional view in the width direction showing a toner conveying roller according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an embodiment of a toner conveyance roller according to the present invention. FIG. 6 is a view showing another embodiment of the toner transport roller of the present invention. 1 is a schematic explanatory diagram illustrating an example of an image forming apparatus.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The charge-controlled urethane foam of the present invention is obtained by impregnating the surface layer with a binder resin that is equal or on the positive side in the charged train than the base urethane foam. Thereby, it is possible to sufficiently prevent the influence of charging due to friction between the toner on the surface of the toner transport roller and the developing roller. Further, by impregnating with such a binder resin, the effect of imparting charging property can be stably exhibited, and a good image can be obtained at low cost.

  Further, when the charge control agent is used, the toner transport roller repeats mechanical friction with the developing roller, so that the positive charge control agent is buried in the urethane foam in the latter half of the continuous use. There was a risk of image blurring due to change in chargeability, but in the present invention, a binder resin that is easily positively charged is used, and the binder resin serves as a positive charge control agent, and a positive charge control agent is used. By not doing so, a better image can be obtained even during continuous use.

  In addition, in this invention, a surface layer shows the range which can acquire the effect of this invention sufficient even if there is little amount of binder resin impregnation, without binder resin impregnating the whole base-material urethane foam.

  In the present invention, the binder resin is not particularly limited as long as it is on the same side or in the positive side of the base urethane foam than the base urethane foam, and is generally a substance that can be used for the urethane foam of the toner conveying roller. Here, specifically, whether the binder resin is located in the positive charge train can be determined by the following method.

(Method for determining the position of the charged column)
A measurement target material (aqueous solution) is applied to a sample plate (dimension: 75 mm × 100 mm × 0.8 mm (thickness), material: SUS304 mirror plate degreased), and then dried in an oven at 100 ° C. A sample plate after drying is placed at 45 degrees in a surface charge measuring device (Kyocera Chemical Co., Ltd., model: TS-100AT) in an atmosphere of 23 ° C. and a relative humidity of 70%. Reference powder MF60 (manufactured by Powder Tech Co., Ltd.) was dropped on the sample plate for 20 seconds, the dropped reference powder was received by a conductive receptor, and the charge amount (nC / g) of the conductive receptor was measured. Determine.

  Examples of the binder resin include nylon resin, melamine resin, reacrylamide, butadiene resin, epoxy resin, alkyd resin, chloroprene rubber, and the like, and preferably has an amide group (—CO—NH—). In particular, nylon resin, urethane resin and the like are preferable. These binder resins can be used alone or as a mixture of two or more if the desired effect of the present invention is obtained.

  Moreover, in this invention, it is preferable that the mass fraction of binder resin with respect to a base-material urethane foam is 9-20 mass%. When it is 9% by mass or more, the effect of the charge control agent can be further obtained. On the other hand, even if it exceeds 20% by mass, the effect of the charge control agent is not drastically improved, and in view of cost, it is preferably 20% by mass or less.

  In the present invention, the impregnation method is not particularly limited as long as the surface layer can be impregnated with the binder resin, and a method of impregnating the solution is usually used. By impregnating the binder resin, the base urethane foam can be charged according to a conventional method.

  In the present invention, a conductive material described later may be blended in the impregnating liquid. Examples of such conductive materials include carbonaceous particles such as carbon black and graphite, metal powders such as silver and nickel, simple conductive metal oxides such as tin oxide, titanium oxide and zinc oxide, or insulating fine particles such as barium sulfate. It is used in one or more combinations selected from those obtained by wet-coating the above conductive metal oxide with a core, conductive metal carbide, conductive metal nitride, conductive metal boride and the like. Carbon black is preferable from the viewpoint of cost, and conductive metal oxide is preferable from the viewpoint of easy control of conductivity.

  Furthermore, in the present invention, the base urethane foam is preferably a base urethane foam impregnated with a carbon conductive material and / or an ionic conductive material described later.

  Furthermore, an appropriate amount of water and an organic solvent such as toluene and ethyl acetate can be added to the impregnating liquid containing the binder resin. These solvents are preferably added so that the viscosity of the impregnating solution is about 5 to 300 cps (25 ° C.). By setting the viscosity within this range, the impregnation work is further facilitated.

  In the present invention, other additives such as mineral oil-based antifoaming agent, silicone-based antifoaming agent, surfactant, charge control agent and the like can be added to the impregnating liquid as necessary. These are preferably added in an amount of about 0.001 to 10 parts by mass, particularly about 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the impregnating liquid.

  Examples of the mineral oil-based antifoaming agent include self-emulsifying silicone-based product names manufactured by Shin-Etsu Chemical Co., Ltd .: KS-508, KS-537, and oil-based silicone-based product names: KF-96, oil. Compound type silicone product name: KF-66 and the like.

  The toner conveying roller of the present invention is such that the above charge-controlled urethane foam is carried on the outer periphery of a shaft, and is suitably applied to an image forming apparatus. FIG. 1 is a cross-sectional view in the width direction of a toner conveying roller according to a preferred embodiment of the present invention. The toner conveying roller of the present invention shown in the figure has a urethane foam 3 whose charge is controlled on the outer periphery of a shaft 1 via an adhesive layer 2. As a result, the effect of charging due to friction between the toner on the surface of the toner conveying roller and the developing roller can be sufficiently prevented, and a good image can be obtained at low cost.

  In the toner conveying roller of the present invention, it is preferable that the binder resin is on the positive side in the charging row with respect to the base urethane foam and is for positively chargeable toner. In general, the amount of charge is determined by various environments and conditions. However, the binder resin of the present invention has a higher rate of reaching a predetermined amount of charge than other compounds in the same charge train. Since it occurs at the contact point of the developing roller, it is important that the roller is made to contain a binder resin in order to charge the toner transport roller for a moment when the roller rotates and rubs the toner. When the toner conveying roller of the present invention is for a positively chargeable toner, it is a binder resin that is positively charged and has a high charging speed compared to the charge control agent contained in the positively chargeable toner used, or more Furthermore, it is preferable to use a binder resin positioned on the positive side of the charged column from the viewpoint that the effects of the present invention can be provided in a small amount. With such a configuration, it is possible to impart positive chargeability to the polyurethane foam, and in addition to physical toner supply by rubbing the toner transport roller with the developing roller, toner and toner exhibiting positive chargeability The toner can be efficiently supplied to the developing roller by electrically repelling the conveying roller.

  FIG. 2 is a view showing an embodiment of the toner conveying roller of the present invention. The positively chargeable toner 20 is adsorbed on the surface layer of the toner transport roller 13 to transport the positively chargeable toner 20, but the surface layer of the toner transport roller 13 is charged to the positive side in the charging row rather than the base urethane foam. Therefore, the toner can be efficiently supplied to the developing roller 12 by electrical repulsion between the positively chargeable toner 20 and the surface layer of the toner conveying roller 13 as indicated by an arrow 22.

  In the toner conveying roller of the present invention, it is preferable that the binder resin is on the positive side in the charging row with respect to the base urethane foam and is for negatively chargeable toner. FIG. 3 is a view showing another embodiment of the toner conveying roller of the present invention. With respect to the negatively chargeable toner 21, the surface layer of the toner transport roller 13 is charged to the positive side in the charging row with respect to the base urethane foam by the binder resin. In the charged toner transport roller 13, the charge amount (charge amount) on the surface of the toner transport roller 13 is controlled by releasing positive charges in the direction of the arrow 23 through the shaft 1 made of a core metal or the like. In this case, if the charge amount of the surface layer of the toner transport roller 13 is small, the toner 20 is hardly attracted to the surface layer of the toner transport roller 13, and as a result, the amount of toner to be transported can be increased. The toner can be efficiently supplied to the roller 12 in the direction of the arrow 24.

  In the present invention, the surface layer is not particularly limited except that the surface layer is impregnated with a binder resin that is equal or on the positive side of the charged train rather than the base urethane foam. And other roller materials can be appropriately determined as desired.

  In the present invention, a urethane foam used as a base material is prepared by converting a compound having two or more active hydrogens and a compound having two or more isocyanate groups into a catalyst, a foaming agent, a regulating agent, by the method described in Japanese Patent No. 3480028. It can be produced by stirring and mixing with an additive such as a foaming agent and foaming and curing, and a method of forming using water as a foaming agent, for example, a prepolymer obtained by reacting an isocyanate component and a polyol component in advance, water A foam-forming material containing dispersed carbon, urethane reaction catalyst, etc. can be produced by a method such as prepolymer method, one-shot method, partial prepolymer method, etc. after foaming in a predetermined shape and then heat-curing. For example, a polyether polyol, isocyanate, water, catalyst, and blowing agent containing a mixture of single diols containing two kinds of single diols having an average molecular weight difference of 800 to 3600 in a total amount of 50% by mass or more based on the polyol component Can be produced by mixing, foaming and standing.

  Here, “single diol” is used to collectively refer to one diol or a group of two or more diols having an average molecular weight difference of 400 or less. Further, the “average molecular weight difference” represents a difference in average molecular weight of each diol as a target, and is used to mean the maximum difference particularly when there are many kinds of combinations.

  Examples of the polyol component used in the production of the prepolymer include polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, polyester polyol obtained by condensing an acid component and a glycol component, and caprolactone ring opening. Polymerized polyester polyol, polycarbonate diol and the like can be used.

  In the present invention, as the polyether polyol used in producing the base urethane foam, (1) for example, a polyether polyol of a type in which only propylene oxide is added to diethylene glycol, (2) for example, propylene oxide in diethylene glycol And a polyether polyol of a type in which ethylene oxide is added in a block or randomly, (3) A polyether polyol of a type grafted with, for example, acrylonitrile or styrene on the above (1) or (2), etc. is not particularly limited. However, in order to exhibit more effect, (1) type polyether polyol is preferable.

  Examples of the initiator used for producing the polyether polyol include polyhydric alcohols, polyhydric phenols, mono- or polyamines, and the like, preferably polyhydric alcohols and polyhydric phenols, and more preferably Is a polyhydric alcohol, and includes, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, and among them, diethylene glycol is particularly preferable.

  The polyether polyol component may also contain a polyol component other than the diol. As such a polyol component, there are usually three functional groups used in the production of a base urethane foam, for example, a glycerin base added with an alkylene oxide such as propylene oxide, and two types such as propylene oxide and ethylene oxide. Examples of the polyfunctional compound include polyether polyols obtained by adding the same compounds as those described above to a sucrose base.

  Examples of polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglucoside, Examples include aromatic diamines, sorbitol, sucrose, phosphoric acid, etc. as starting materials and addition polymerization of ethylene oxide and propylene oxide. Especially, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane. Those starting from hexanetriol are preferred. As for the ratio of ethylene oxide and propylene oxide to be added and the microstructure, the ratio of ethylene oxide is preferably 2 to 95% by mass, more preferably 5 to 90% by mass, and ethylene oxide is added to the terminal. preferable. In addition, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random.

  The molecular weight of the polyether polyol is bifunctional when water, propylene glycol or ethylene glycol is used as a starting material, and preferably has a weight average molecular weight in the range of 300 to 6000, preferably in the range of 3000 to 5000. Is more preferable. Further, when glycerin, trimethylolpropane, and hexanetriol are used as starting materials, they are trifunctional, and those having a weight average molecular weight in the range of 900 to 9000 are preferable, and those in the range of 4000 to 8000 are more preferable. Furthermore, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used.

  Polytetramethylene ether glycol can be obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight in the range of 400 to 4000, particularly in the range of 650 to 3000 are preferably used. It is also preferable to blend polytetramethylene ether glycols having different molecular weights. Furthermore, polytetramethylene ether glycol obtained by copolymerizing alkylene oxide such as ethylene oxide or propylene oxide can also be used.

  Furthermore, it is also preferable to blend and use polytetramethylene ether glycol and a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide. In this case, it is preferable that these blend ratios are used in a mass ratio of 95: 5 to 20:80, particularly 90:10 to 50:50.

  In addition to the polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, a diol such as butanediol, a polyol such as trimethylolpropane, or a derivative thereof may be used in combination.

  As the polyisocyanate component used in the present invention, aromatic isocyanate or a derivative thereof, aliphatic isocyanate or a derivative thereof, alicyclic isocyanate or a derivative thereof is used. Among these, aromatic isocyanate or a derivative thereof is preferable, and in particular, tolylene diisocyanate (TDI) or a derivative thereof, diphenylmethane diisocyanate (MDI) or a derivative thereof, polymethylene polyphenyl isocyanate or a derivative thereof is preferably used. Used.

  Tolylene diisocyanate or derivatives thereof include crude tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, these These are urea-modified products, burette-modified products, carbodiimide-modified products, urethane-modified products modified with polyols, and the like. As diphenylmethane diisocyanate or a derivative thereof, for example, diphenylmethane diisocyanate or a derivative thereof obtained by phosgenating diaminodiphenylmethane or a derivative thereof is used. Examples of the derivatives of diaminodiphenylmethane include polynuclear bodies, and pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, polymeric diphenylmethane diisocyanate obtained from a polynuclear body of diaminodiphenylmethane, and the like can be used. Regarding the number of functional groups of polymeric diphenylmethane diisocyanate, a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is usually used, and the average number of functional groups is preferably 2.05 to 4.00, more preferably 2. .50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates or derivatives thereof, such as urethane modified products modified with polyols, dimers formed by uretidione formation, isocyanurate modified products, carbodiimide / uretonimine modified products, allophanate modified products Further, urea-modified products, burette-modified products and the like can also be used. Also, several types of diphenylmethane diisocyanate and its derivatives can be blended and used.

  In the present invention, as a prepolymerization method, a polyol and an isocyanate are put in a suitable container and sufficiently stirred, and the temperature is 30 to 90 ° C., more preferably 40 to 70 ° C., and 6 to 240 hours, more preferably 24. The method of keeping warm for 72 hours is mentioned. In this case, the ratio of the amount of polyol and isocyanate is preferably adjusted so that the isocyanate content of the resulting prepolymer is 4 to 30% by mass, more preferably 6 to 15% by mass. If the isocyanate content is less than 4% by mass, the stability of the prepolymer is impaired, and the prepolymer may be cured during storage, making it impossible to use. Further, when the isocyanate content exceeds 30% by mass, the content of isocyanate that has not been prepolymerized increases, and this polyisocyanate undergoes a prepolymerization reaction with a polyol component used in the subsequent polyurethane curing reaction. The effect of using the prepolymer method is diminished because it cures by a reaction mechanism similar to the one-shot process.

  In addition to the polyol component and the isocyanate component, a conductive material such as carbon black, a crosslinking agent, a surfactant, a catalyst, a foam stabilizer, and the like can be added to the base urethane foam as desired. It can be set as the layer structure according to. In addition, flame retardants, fillers, antioxidants, ultraviolet absorbers and the like can be used as appropriate.

  Examples of ionic conductive materials include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethyl Perchlorate such as ammonium, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, ammonium salt such as sulfonate, lithium, Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, trifluoromethyl sulfates of alkali metals and alkaline earth metals such as sodium, potassium, calcium and magnesium Salts, sulfonic acid salts, and the like.

  Examples of the carbon conductive material include gas black such as Denka black, ketjen black, and acetylene black, oil furnace black including ink black, thermal black, channel black, lamp black, and the like. The urethane foam is preferably impregnated with such a carbon conductive material or internally added with a carbon conductive material.

  Furthermore, examples of the electronic conductive material include conductive metal oxides such as tin oxide, titanium oxide, and zinc oxide; metals such as nickel, copper, silver, and germanium. These conductive materials may be used alone or in combination of two or more. There is no restriction | limiting in particular in the compounding quantity, Although it can select suitably as desired, Usually, 0.1-40 mass parts with respect to 100 mass parts of total amounts of a polyol and isocyanate, Preferably 0.3-20 It is a ratio of parts by mass.

  Moreover, in order to stabilize the cell of a foam material, it is preferable to mix | blend a silicone foam stabilizer and various surfactant in a base-material urethane foam. As the silicone foam stabilizer, a dimethylpolysiloxane-polyoxyalkylene copolymer or the like is suitably used, and those composed of a dimethylpolysiloxane moiety having a molecular weight of 350 to 15000 and a polyoxyalkylene moiety having a molecular weight of 200 to 4000 are particularly preferable. . The molecular structure of the polyoxyalkylene moiety is preferably an addition polymer of ethylene oxide or a co-addition polymer of ethylene oxide and propylene oxide, and its molecular terminal is preferably ethylene oxide. Examples of the surfactant include cationic surfactants, anionic surfactants, ionic surfactants such as amphoteric, nonionic surfactants such as various polyethers and various polyesters. These may be used alone or in combination of two or more. The blending amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of the polyol component and the isocyanate component. More preferably.

  In the present invention, the compound used as the foaming agent is not particularly limited in the type and amount used, and known compounds can be used. As the foaming agent, for example, methylene chloride, Freon 123, Freon 141b or the like is used.

  Catalysts used for the curing reaction of the base urethane foam include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine, pentamethyldiethylenetriamine, and pentamethyldipropylenetriamine. , Triamines such as tetramethylguanidine, triethylenediamine, dimethylpiperazine, methylethylpiperazine, cyclic amines such as methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, Alcohol amines such as methylhydroxyethylpiperazine and hydroxyethylmorpholine Ether amines such as bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl) aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimaleate And organometallic compounds such as dioctyltin marker peptide, dioctyltin thiocarboxylate, phenylmercury propionate, lead octenoate and the like. These catalysts may be used alone or in combination of two or more.

In the present invention, air permeability of the charge control urethane foam ^is preferably 100~700cm ^{3 /} cm 2 ^/ sec, in ^particular, more preferably 150~400cm ^{3 /} cm 2 ^/ sec of about . If the air flow rate exceeds 700 cm ³ / cm ² / sec, the toner fuel consumption may decrease due to excessive concentration, whereas if it is less than 100 cm ³ / cm ² / sec, the impregnating liquid is impregnated with the base urethane foam. It may be difficult to impregnate, and the amount of binder resin attached may not be constant. In addition, productivity may decrease due to the influence. In addition, the said air flow rate is measured according to JIS K 6400.

  In the present invention, the number of cells of the charge-controlled urethane foam is preferably 20 to 80 cells / inch (25.4 mm), and more preferably 30 to 60 cells / inch. If the number of cells is less than 20 cells / inch, the space to which the toner adheres is reduced, which tends to affect development. On the other hand, if the number of cells is more than 80 cells / inch, the impregnating liquid is impregnated with the base urethane foam. In some cases, the amount of the binder resin deposited is difficult to be constant. In addition, the impregnation speed is also slow, which may increase the cost.

  Further, the average cell diameter of the charge-controlled urethane foam is preferably 50 to 1000 μm, and more preferably about 100 to 400 μm. When the average cell diameter exceeds 1000 μm, the toner fuel consumption may decrease due to excessive concentration. On the other hand, when the average cell diameter is less than 50 μm, it becomes difficult to impregnate the impregnating liquid with the base urethane foam. The amount of adhesion may not be constant.

In the present invention, the density of the charge control urethane foam is preferably 10 to 100 kg / ^{m 3,} in particular, and more preferably about 10 to 50 kg / ^{m 3.} If the density exceeds 100 kg / m ³ , the cost may increase. On the other hand, if the density is less than 10 kg / m ³ , the compressive residual strain tends to deteriorate, resulting in loss of follow-up and causing blurring. is there.

  The charge-controlled polyurethane foam preferably has an Asker F hardness of 30 to 90 °. If the hardness is greater than 90 °, the toner may be deteriorated, and if it is less than 30 °, polishing failure tends to occur, which is not preferable.

  The shaft 1 used in the roller of the present invention is not particularly limited, and any of them can be used. For example, a steel material such as sulfur free-cutting steel plated with nickel or zinc, or iron Furthermore, a metal shaft such as a metal core made of a solid metal such as stainless steel or aluminum, or a metal cylinder hollowed out inside can be used. In the present invention, the diameter of the shaft 1 is preferably less than φ6 mm, for example, 5.0 mm, and the thickness of the charge-controlled urethane foam 3 is preferably less than 4.5 mm, for example, 4.0 mm. It is. Thereby, the weight of the roller can be reduced, and the elastic modulus of the urethane foam when viewed in a macro is increased by thinning the charge-controlled urethane foam 3, and the toner scraping property is improved. Further, due to the volume reduction of the urethane foam by thinning the charge-controlled urethane foam 3, the amount of toner contained in the charge-controlled urethane foam 3 during printing durability is reduced, and the toner fuel consumption can be suppressed.

  Further, in the roller of the present invention, it is preferable to provide an adhesive layer 2 between the shaft 1 and the charge-controlled urethane foam 3 as shown in the figure. As the adhesive used for the adhesive layer 2, a hot-melt polymer adhesive mainly composed of an adipate-based polyurethane resin having a melting point of 120 ° C. or higher, particularly 130 ° C. or higher and 200 ° C. or lower can be suitably used.

The properties of the adhesive may be any form such as a film or a pellet. Further, the thickness of the adhesive layer 2 is preferably 20 to 300 μm. If it is too thin, poor adhesion occurs, and if it is too thick, a suitable roller resistance cannot be obtained. The melting temperature of the adhesive at the time of bonding is preferably 100 ° C. or higher, particularly 130 ° C. or higher and 200 ° C. or lower, and preferably lower than the melting point of the adhesive. As a result, the adhesive layer 2 becomes a semi-molten state, and it is easier to control the voltage dependency such that the roller resistance when applying 5 V is 10 ⁶ to 10 ⁸ Ω and the roller resistance when applying 100 V is 10 ² to 10 ⁴ Ω. Thus, it is possible to increase the density in the initial printing durability.

  In the toner conveying roller of the present invention, the charge-controlled urethane foam 3 is supported on the outer periphery of the shaft 1 via an adhesive as desired, and then the shaft 1 and the charge-controlled urethane foam 3 are placed at a predetermined temperature. It can be manufactured by heating and bonding.

  Specifically, first, a urethane foam that has not been subjected to a block-shaped (16 mm × 1000 mm × 2000 mm) film removal treatment in a bath filled with this impregnating solution by mixing a binder and an antifoaming agent. After being immersed and compressed between two rolls, it is opened and impregnated liquid is impregnated with urethane foam. This is introduced onto a bath, passed through a nip roll to squeeze and remove excess impregnating liquid, and then heated and dried in a hot air oven at 110 ° C. for 10 minutes to produce a charge-controlled urethane foam 3. The charge-controlled urethane foam 3 that can be molded by this method becomes a foam having a low hardness, for example, an Asker F hardness of 30 to 90 °, compared with that obtained by mechanical gas filling.

  Further, a film of adhesive is formed on the outer periphery of the shaft 1 by winding a film adhesive or by melting and applying a pellet adhesive. Thereafter, a hole is made in the charge-controlled urethane foam 3, and the shaft 1 with adhesive is inserted into the hole. Thereafter, heating is performed at a predetermined temperature to integrate the shaft 1 and the charge-controlled urethane foam 3 through the adhesive layer 2, and the surface of the charge-controlled urethane foam 3 is polished to obtain a desired cylindrical shape. Further, the end of the charge-controlled urethane foam 3 is cut into a predetermined shape, whereby the toner transport roller of the present invention can be obtained.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

<Material>
The materials used in the examples and comparative examples are shown below.
Urethane foam A manufactured by Bridgestone Corporation (no film removal treatment)
Density 29kg / m ³
Aeration rate 196cm ³ / cm ² / sec
Hardness 10kgf
Average cell diameter 280μm
Binder a Nylon binder resin
Made by Toray Industries, Inc.
"AQ-Nylon T-70" modified nylon dispersion
Solid content 50%
Binder b Urethane binder resin
"SE binder" urethane resin water dispersion manufactured by Enex
Solid content 50%
Binder c Acrylic binder resin
"BS-050301-1" manufactured by Enex
Acrylonitrile / alkyl acrylate copolymer emulsion charge control agent Silicone powder aqueous solution
Made by Toray Industries, Inc.
"TREFIL E601 dispersion aqueous solution"
Solid content 50%
Defoaming agent “KS-502” manufactured by Shin-Etsu Silicone Co., Ltd.

<Example 1>
According to the blending amount shown in Table 2 below (mass fraction (mass%) of blending material (g / L) with respect to urethane foam A (g / L)), the binder a and the antifoaming agent were mixed to prepare an impregnation solution. . In a bath filled with this impregnating liquid, urethane foam A that has not been subjected to film removal treatment in the form of a block (16 mm × 1000 mm × 2000 mm) is immersed, compressed between two rolls, and then released to form an impregnating liquid. Urethane foam A was impregnated. This was introduced onto a bath, passed through a nip roll to squeeze and remove excess impregnating liquid, and then heated and dried in a hot air oven at 110 ° C. for 10 minutes to obtain a charge-controlled urethane foam. The charge amount of the impregnating liquid of the charge-controlled urethane foam was 14.9% by mass in terms of dry mass. Here, the adhesion amount indicates the mass fraction (mass%) of the solid content (g) with respect to the mass (g) of the urethane foam A.

  The adhering amount of the impregnating liquid is adjusted by adjusting the pressure when the block-like urethane foam is taken out from the impregnating liquid, or by changing the concentration of the charge control agent and the binder in the impregnating liquid. can do.

  A shaft (diameter: 6.0 mm, length: punched through a hole for inserting a shaft in the block-shaped charge-controlled urethane foam impregnated with the charge control agent and binder thus obtained, and coated with an adhesive. 250 mm) was inserted into the hole, and then the block-like urethane foam was ground to obtain a foamed elastic body having a uniform thickness to produce the toner conveying roller of the present invention.

<Reference Example 1>
Binder b was used as the binder resin for the impregnating liquid, the nip roll interval was adjusted, and the adhering liquid adhesion amount (dry mass) was 14.9% by mass. Other than that, a toner conveying roller was produced in the same manner as in Example 1.

<Comparative Example 1>
Example 1 except that binder c was used as the binder resin for the impregnating liquid, a charge control agent was blended, the nip roll interval was adjusted, and the adhering amount (dry mass) of the impregnating liquid was 21.4% by mass. A toner conveying roller was produced in the same manner as described above.

  For the impregnating liquids of Example 1, Reference Example 1 and Comparative Example 1, the charge amount (nC / g) was measured according to the following method. The results are shown in Table 1 below.

(Measurement of surface charge)
After applying the impregnating liquids of Example 1, Reference Example 1 and Comparative Example 1 to a sample plate (dimensions: 75 mm × 100 mm × 0.8 mm (thickness), material: SUS304 mirror plate degreased), 100 ° C. Dried in the oven. Each sample plate after drying was placed at 45 degrees in a surface charge measurement device (Kyocera Chemical Co., Ltd., model: TS-100AT) in an atmosphere of 23 ° C. and a relative humidity of 70%. Reference powder MF60 (manufactured by Powdertech Co., Ltd.) was dropped on each sample plate for 20 seconds, the dropped reference powder was received by a conductive receptor, and the charge amount (nC / g) of the conductive receptor was measured.

<Example 2>
9.5% by mass of binder a was used as the binder resin for the impregnating liquid, the nip roll interval was adjusted, and the amount of impregnating liquid deposited (dry mass) was 9.8% by mass. Other than that, a toner conveying roller was produced in the same manner as in Example 1.

<Example 3>
Binder a was used in an amount of 4.3% by mass as the binder resin of the impregnating liquid, the nip roll interval was adjusted, and the adhering liquid adhering amount (dry mass) was 9.0% by mass. Other than that, a toner conveying roller was produced in the same manner as in Example 1.

<Evaluation>
The physical properties of the toner transport rollers obtained in Examples 1 to 3, Reference Example 1 and Comparative Example 1 were evaluated as follows. The results are also shown in Table 2 below.

(1) Average cell diameter (μm)
The surface of the urethane foam was imaged with a microscope, the cell diameter of the surface of the urethane foam was measured, and the average was obtained.

(2) Asker F hardness (°)
Urethane foam was placed on a rigid plate and measured with a polymer instrument Asker F hardness meter. The measurement was carried out by placing the hardness meter gently and measuring the hardness after 10 seconds.

(3) Aeration rate (cm ³ / cm ² / sec)
Measurement was performed according to JIS K 6400.

(4) Number of cells (pieces / inch)
Measurement was performed according to JIS K 6400.

(5) Skeletal shape The surface of the urethane foam was photographed at a magnification of 100 times, and the presence or absence of an edge in the shape of the skeleton (the one with the urethane skeleton not rounded is regarded as having an edge) was determined.

(6) Image evaluation The toner conveying rollers obtained in Examples 1 to 3, Reference Example 1 and Comparative Example 1 were set in a commercially available printer, and printing was performed under the following conditions to evaluate the printing performance.
Printing 20000 sheets with a 4% print pattern on A4 paper. When printing 20000 sheets, 100% black continuous pattern printing is performed every four thousand sheets. A total of 20 continuous printings of 100% black 100% patterns are performed, and evaluation is performed in the following four stages each time, and an average of 20 times is calculated (image average evaluation). Further, a negatively chargeable toner was used as the toner.
(Evaluation criteria)
The case where blur occurs on the first or second sheet out of four sheets is marked with x.
A case where a blur occurs on the third of the four sheets is indicated by Δ.
A case where a blur occurs on the fourth of the four sheets is marked with ◯.
A case where no blur occurs on all four sheets is marked with ◎.

Printing 20000 sheets with 1% printing pattern on A4 paper. The image durability was evaluated by evaluating the following four stages according to the number of sheets when blurring occurred when printing 20000 sheets (image durability evaluation).
(Evaluation criteria)
The case where blur occurs in the middle of 0 or more and less than 10,000 sheets is defined as x.
A case where blur occurs at the 10,000th or more and less than 15000th sheet is indicated by Δ.
A case where blur occurs in 15000 or more and less than 20000 sheets is marked with ◯.
The case where no blur has occurred up to 20000 sheets is marked with ◎.

(Q / M evaluation)
The toner conveying rollers obtained in Examples 1 to 3, Reference Example 1 and Comparative Example 1 were set in a commercially available printer, printing was performed under the following conditions, and the surface charge amount (Q / M) during durability was evaluated. .
2000 sheets are printed with a 4% print pattern on A4 paper. The surface charge amount (Q / M: unit C / mg) from 0 to 2000 sheets was measured to obtain the standard deviation σ (unit C / mg) of Q / M and evaluated in the following three stages. The surface charge amount (Q / M) was measured by the same method as described above.
(Evaluation criteria)
○: Q / M standard deviation σ of 0 to 2000 sheets is less than 3 C / mg Δ: Q / M standard deviation σ of 0 to 2000 sheets is 3 C / mg or more and less than 5 C / mg x: 0 to 2000 sheets Q / M standard deviation σ up to 5C / mg or more

※厚みを１０ｍｍとした。

* Thickness was 10 mm.

  Since the impregnating liquid of Comparative Example 1 uses the binder c that is on the negative side in the charging train than the base urethane foam, a sufficient positive charge amount cannot be obtained, and good image durability is obtained. I couldn't. On the other hand, in Examples 1 to 3 and Reference Example 1, both the image average evaluation and the image durability evaluation were good.

  In Examples 1 and 2, since the added amount of the binder was 9 to 20% by mass, the standard deviation of Q / M was small, and a better image was obtained. In Reference Example 1, since a urethane-based binder was used, the standard deviation was larger than in Examples 1 and 2, although it was good.

DESCRIPTION OF SYMBOLS 1 axis | shaft 2 contact bonding layer 3 charge-controlled urethane foam 11 image forming body 12 developing roller 13 toner conveyance roller 14 toner accommodating part 15 transfer roller 16 charging part 17 exposure part 18 blade 20 positively chargeable toner 21 negatively chargeable toner 22 arrow 23 arrow 24 arrow

Claims (4)

  The surface layer is impregnated with a binder resin that is equal or on the positive side in the electrification row with respect to the base urethane foam, and the amount of the impregnating liquid containing the binder resin attached to the base urethane foam is 9. 0 to 14.9% by mass, wherein the base urethane foam is a base urethane foam impregnated with a carbon conductive material, and the binder resin contains a nylon resin. Controlled urethane foam. A toner conveying roller, wherein the charge-controlled urethane foam according to claim 1 is carried on an outer periphery of a shaft. The toner conveying roller according to claim 2 , wherein the binder resin is on the positive side in the charging row with respect to the base urethane foam and is for negatively chargeable toner. The toner conveying roller according to claim 2 , wherein the binder resin is on the positive side in the charging row with respect to the base urethane foam and is for positively chargeable toner.

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