JP3923217B2 - Conductive polyurethane member, image forming apparatus component using the same, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive polyurethane member, an image forming apparatus component using the same, and an image forming apparatus. More specifically, the present invention relates to a conductive polyurethane member that is suitably used in an electrophotographic process having excellent characteristics, an image forming apparatus component using the same, and a charging component, a developing component, and a toner supply component. The present invention relates to an image forming apparatus mounted as a component, a transfer component, or a cleaning component.
[0002]
[Prior art]
In recent years, with the advancement of electrophotographic technology, in an image forming apparatus such as a dry electrophotographic apparatus, conductive polyurethane is used as a member for parts used for charging, developing, transferring, toner supplying, cleaning, etc. Members are attracting attention, and are used in the form of elastic rollers such as charging rollers, developing rollers, transfer rollers, toner supply rollers, and cleaning rollers, and blades having elasticity such as toner layer regulating blades and cleaning blades. .
The polyurethane members used for these purposes are usually filled with polyurethane elastomer or polyurethane foam, and they have low hardness and do not contaminate the photoreceptor or transfer material. ^Four -10 ^Ten There is a demand for properties such as having a predetermined resistance value in a medium resistance region of Ω, and having extremely low electrical resistance positional variation and voltage dependency.
As a method for imparting conductivity to a polyurethane member, there are a method of mixing metal or metal oxide powder or carbon black, and a method of blending an electrolyte with a raw material. However, it is difficult to produce a polyurethane member having a constant resistance value in the middle resistance region required for the electrophotographic process with good reproducibility by the method of mixing metal or metal oxide powder or carbon black. Even if such a polyurethane member can be manufactured, there is a problem that the positional variation of the electric resistance is large and the voltage dependency of the electric resistance is large.
On the other hand, by mixing an electrolyte (ionic conductive agent) such as sodium perchlorate with a polar polyurethane material such as polyether polyurethane or polyester polyurethane, resistance variation and resistance voltage in the low resistance and medium resistance region. A polyurethane member that is substantially free of dependence can be produced. In addition, the conductivity of a conductive polyurethane obtained by adding an electrolyte to polyurethane can be adjusted by changing the composition of the polyurethane and the type and amount of the electrolyte to be added. Considering the ease of manufacturing, it is important to minimize the number of steps required to switch polyurethane members with various resistance values in the same manufacturing facility and to change the composition of polyurethane and the type and amount of electrolyte. Therefore, it is advantageous that polyurethane members having various resistance values can be produced by changing the amount of the electrolyte without changing the composition of the polyurethane and the type of the electrolyte to be added.
However, if the amount of the electrolyte added to the polyurethane member is increased to produce a low-resistance polyurethane member, and the low-resistance polyurethane member is used in contact with a photoreceptor or the like, the electrolyte in the low-resistance polyurethane member When the low resistance polyurethane member is brought into contact with toner and used for a member, the electrolyte deposited on the surface of the member causes toner fusion. there were.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to overcome the problems of the conventional conductive polyurethane member and to provide a conductive polyurethane member excellent in various characteristics, an image forming apparatus component and an image forming apparatus using the conductive polyurethane member. To do.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that a specific polyurethane member obtained by adding a specific non-conductive oil-absorbing substance to conductive polyurethane contaminates the photoreceptor. In addition, the present inventors have found that it is suitable as a member for an image forming apparatus such as an electrophotographic apparatus because it has low hardness without fusing with toner and has extremely low electrical resistance positional variation and voltage dependency. The present invention has been completed based on such findings.
That is, the present invention Conductivity is given by adding electrolyte. In the conductive member made of polyurethane, the polyurethane member is Trifunctional polyether polyol starting from glycerin having a weight average molecular weight of 1500 to 6000 A polyurethane member obtained by mixing and curing a component, a polyisocyanate component, and a non-conductive oil-absorbing substance, Selected from light calcium carbonate and magnesium carbonate having an oil absorption of 20 to 120 [milliliter / 100 g] Extraction rate of conductive polyurethane when non-conductive oil-absorbing substance is contained and the non-conductive oil-absorbing substance is added in the amount Z [wt%]. [Extraction rate of Soxhlet extraction with acetone solvent at 90 ° C. for 8 hours] Is X [wt%], and the oil absorption amount of the non-conductive oil absorbing material to be blended is Y [milliliter / 100 g],
0.5 X ≦ 0.01YZ ≦ 4 X
Conductive polyurethane member satisfying the requirements, an image forming apparatus component configured using the conductive polyurethane member and used in contact with a photoreceptor or toner, and mounting of these image forming apparatus components An image forming apparatus is provided.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The conductive polyurethane member of the present invention is a polyurethane member obtained by adding a non-conductive oil-absorbing substance to conductive polyurethane.
Non-conductive oil-absorbing substances include light, heavy, fine powder, fatty acid treated calcium carbonate, magnesium carbonate, clay, calcined clay, silane modified clay, talc, silica, wollastonite, zeolite, diatomaceous earth, silica sand, Slate powder, pumice powder, alumina white, ammonium sulfate, barium sulfate, lithopone, calcium sulfate, magnesium oxide, molybdenum disulfide, aluminum hydroxide, magnesium hydroxide, zirconium silicate, etc. are used, and calcium carbonate and magnesium carbonate are particularly preferred. .
The oil absorption amount of the non-conductive oil-absorbing substance blended in the conductive polyurethane is preferably 10 to 200 [milliliter / 100 g], particularly preferably 20 to 120 [milliliter / 100 g]. The blending amount Z [wt%] of the nonconductive oil-absorbing substance is X [wt%] when the nonconductive oil absorbing substance is not added, and Y is the oil absorption amount of the nonconductive oil absorbing substance to be blended. [Milliliter / 100g]
0.1X ≦ 0.01YZ ≦ 7X
However, preferably,
0.5 X ≦ 0.01YZ ≦ 4X
Is an amount that satisfies Here, the blending amount Z [wt%] of the non-conductive oil-absorbing substance refers to the blending ratio in the conductive polyurethane composition. The oil absorption amount of the non-conductive oil-absorbing substance is a value measured by the same method as the carbon black oil absorption measurement method defined in JIS K6221 clause 6.1.2. In addition, the extraction rate of conductive polyurethane refers to the conductivity of the extract obtained by chopping about 5 g of conductive polyurethane into a small piece of about 3 mm square, using a cylindrical filter paper, and using acetone as an extraction solvent at 90 ° C. for 8 hours with a Soxhlet extractor. It is a weight percentage with respect to the conductive polyurethane. Examples of such an extract include a low molecular polyurethane that is insufficient in chain extension due to a urethane reaction, a silicone foam stabilizer, a surfactant, an electrolyte, and the like blended in the raw material.
The meaning of the above formula is as follows. That is, the component contained in the polyurethane member that contaminates the photoreceptor or fuses the toner is closely related to the extraction component extracted with the solvent, and is related to the action mechanism of the present invention described later. In order to absorb 10% of the extracted component, and more preferably 50% of the extracted component, depending on the oil absorbing material, the lower limit of the oil absorbing material addition amount is indicated. Rises, and it becomes necessary to increase the capacity of the raw material pump and to reduce the speed of producing the polyurethane member. In order to avoid this, the upper limit is set in the above formula.
Some oil-absorbing substances exhibit conductivity such as carbon black and conductive zinc white. As long as the effect of the present invention is not impaired, these conductive oil-absorbing substances can be blended with the conductive polyurethane member of the present invention. However, the addition of these conductive oil-absorbing substances usually increases the voltage dependency of the electrical resistance. So be careful.
[0006]
As the polyol component constituting the polyurethane member of the present invention, polyether polyol or polyester polyol is used, and polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide is particularly preferable. Polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide are, for example, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglucotite, 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, hexane Those starting from triol are preferred. Although there is no restriction | limiting in particular about the ratio and microstructure of ethylene oxide and propylene oxide to add, The ratio of ethylene oxide is 2-80 weight%, More preferably, it is 5-25 weight%. And what has ethylene oxide added to the terminal is preferably used. Further, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random.
[0007]
The molecular weight of the polyether polyol is not particularly limited. However, when water, propylene glycol, or ethylene glycol is used as a starting material, it becomes bifunctional and preferably has a weight average molecular weight in the range of 300 to 6000, particularly 400 to 3000. The thing of the range of is preferable. When glycerin, trimethylolpropane, and hexanetriol are used as starting materials, they are trifunctional and preferably have a weight average molecular weight in the range of 900 to 9000, particularly preferably in the range of 1500 to 6000. Further, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used.
[0008]
It is preferable that polytetramethylene ether glycol is included as a polyol component constituting the polyurethane member of the present invention. Polytetramethylene ether glycol is obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight 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.
It is also preferable to blend a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide and polytetramethylene ether glycol. In this case, a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, and polytetramethylene It is preferably used so that the ratio with respect to ether glycol is in the range of 90:10 to 10:90, and particularly preferably in the range of 70:30 to 40:60.
In addition to the above-described polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, an acid component such as adipic acid and a glycol component such as ethylene glycol are condensed within the range in which the object of the present invention is not impaired. Polyester polyols obtained by ring-opening polymerization of ε-caprolactam, diols such as polycarbonate diol and butanediol, polyols such as trimethylolpropane, and derivatives thereof can be used in combination.
[0009]
As a polyisocyanate component constituting the polyurethane member, diphenylmethane diisocyanate or a derivative thereof is used. Although there is no restriction | limiting in particular as this diphenylmethane diisocyanate or its derivative (s), For example, the diphenylmethane diisocyanate or its derivative (s) obtained by phosgenating diaminodiphenylmethane or its derivative (s) 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. The number of functional groups of polymeric diphenylmethane diisocyanate is not particularly limited, but usually a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is used, and the average number of functional groups is preferably 2. 0.05 to 4.00, more preferably 2.50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates or their derivatives, such as urethane-modified products modified with polyols, dimers formed by uretidione formation, isocyanurate-modified products, carbodiimide / uretonimine-modified products, allophanate-modified products , Urea-modified products, burette-modified products, and the like can be used. Of these, urethane-modified products and carbodiimide / uretonimine-modified products are particularly preferable.
[0010]
In the present invention, one kind of diphenylmethane diisocyanate or a derivative thereof may be used, or two or more kinds may be used in combination. In addition, if desired, various aliphatic isocyanates such as tolylene diisocyanate and various aliphatic isocyanates such as hexamethylene diisocyanate, together with the above-mentioned diphenylmethane diisocyanate and derivatives thereof, as long as the object of the present invention is not impaired. An alicyclic isocyanate such as isophorone diisocyanate or a derivative thereof can be used in combination.
There are no particular restrictions on the amount of diphenylmethane diisocyanate or its derivatives, but the ratio of isocyanate groups in the polyisocyanate component to hydroxyl groups in the polyol component is usually in terms of molar ratio. The blending amount is preferably set to be 0.9 to 1.5, and more preferably 1.0 to 1.2.
[0011]
There are no particular restrictions on the conductivity-imparting material added to constitute the conductive polyurethane member. For example, carbon black such as oil furnace black including gas black and ink black, thermal black, channel black, and lamp black, conductivity Examples thereof include conductive metal oxides such as zinc white, but it is preferable to impart conductivity with an electrolyte in order to suppress positional variation in electrical resistance and voltage dependency. The electrolytes include tetraethylammonium, tetrabutylammonium, lauraltrimethylammonium, stearyltrimethylammonium, octadecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, modified aliphatic dimethylethyammonium, lauroylaminopropyldimethylethylammonium. Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides of alkali metals such as quaternary ammonium such as lithium and sodium or alkaline earth metals such as calcium and magnesium , Sulfate, alkyl sulfate, carboxylate, sulfonate, trifluoromethyl sulfate, and the like. Among these, quaternary ammonium salts of alkyl sulfates and quaternary ammonium salts of polybasic carboxylic acids are preferable, and quaternary ammonium alkyl sulfates having an amide bond are particularly preferable. The blending amount of the electrolyte is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the polyurethane material.
[0012]
Examples of a reaction catalyst for curing a polyurethane composition containing a polyurethane material and an electrolyte include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine, and penta Triamines such as methyldiethylenetriamine, pentamethyldipropylenetriamine, tetramethylguanidine, cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxy Ethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine, hydro Alcohol amines such as ciethylmorpholine, ether amines such as bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl) aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker butylide, Examples thereof include organic metal compounds such as dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker butylide, dioctyltin thiocarboxylate, phenylmercury propionate, and lead octenoate. Of these, organotin catalysts are particularly preferred. These catalysts may be used alone or in combination of two or more.
[0013]
When the conductive polyurethane member of the present invention is in the form of foam, it is preferable to blend a silicone foam stabilizer and various surfactants in the polyurethane composition in order to stabilize the cells of the foam material. 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, surfactants such as amphoteric, and nonionic surfactants such as various polyethers and various polyesters.
The blending amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the polyurethane material.
[0014]
The foaming method for producing the polyurethane foam is not particularly limited, and a known method, for example, a method using a foaming agent such as water, an organic solvent or various alternative chlorofluorocarbons, or a method of mixing bubbles by mechanical stirring is preferably used. It is done. Among these, a method of mixing bubbles by mechanical stirring is particularly preferable. The expansion ratio of the polyurethane foam is not particularly limited, but the maximum cell diameter is preferably less than 500 μm, and particularly preferably the maximum cell diameter is less than 200 μm. The bulk density is preferably in the range of 0.2 to 0.7 g / ml, and particularly preferably in the range of 0.3 to 0.6 g / ml.
[0015]
The blending and heat curing for producing the conductive polyurethane member of the present invention are carried out by mixing and stirring the above polyol component, isocyanate component, electrolyte, reaction catalyst and various additive components used as required, and by the above method as necessary. It is preferable to use a method in which air bubbles are mixed and heat-cured after an operation such as casting into a predetermined mold or the like or free foaming in a block shape.
In addition, a polyol component and a polyisocyanate component are reacted in advance to prepare a prepolymer having an isocyanate group, and this is cured using a chain extender such as ethylene glycol, 1,4-butadiol, trimethylolpropane or the like. A prepolymer method can also be used.
Although the conductive polyurethane member of the present invention does not contaminate the photoreceptor or the like and does not fuse the toner, it is unclear, but the contaminants that migrate from the polyurethane member to the photoreceptor or the toner on the surface of the polyurethane member are fused. It is estimated that the non-conductive oil-absorbing substance contained in the polyurethane member will adsorb the substance to be made.
[0016]
The image forming apparatus component, which is the main application field of the conductive polyurethane member of the present invention, is composed of a conductive polyurethane member and a metal member, and there is no particular limitation on the structure thereof. A metal member obtained by plating zinc such as sulfur free-cutting steel or a metal member such as aluminum or stainless steel, with a part or the whole coated with the conductive polyurethane member of the present invention. Used in the form of rollers, drums, blades, etc. That is, when the image forming apparatus component is a medium resistance elastic conductive roller, a core metal obtained by plating sulfur free cutting steel or the like with zinc or the like is coated with a conductive polyurethane foam in a cylindrical shape, and further required. Correspondingly, an example in which a conductive, semiconductive or insulating paint is applied to the outside can be exemplified.
[0017]
There is no particular limitation on the method for joining the metal member and the conductive polyurethane member. However, the metal member is disposed in the mold in advance and the polyurethane composition is cast and cured, or the conductive polyurethane member is formed into a predetermined shape. A method of bonding after molding can be used. In either method, if necessary, an adhesive layer can be provided between the metal member and the conductive polyurethane foam. As this adhesive layer, a known material such as an adhesive made of a conductive paint or a hot melt sheet can be used. Can be used.
There is no restriction | limiting in particular as a shaping | molding method of the electroconductive polyurethane member of this invention, The method of cutting out to a predetermined dimension by cutting from a block other than a well-known method, for example, the method of casting to the mold of the predetermined shape mentioned above In addition, a method of making a predetermined size by polishing treatment, a method of appropriately combining these methods, or the like can be used.
There are no particular restrictions on the types of image forming apparatus parts using the conductive polyurethane of the present invention, but as the image forming apparatus parts used in contact with the photoreceptor, a charging roller, a developing roller, a toner supply roller, and a transfer roller , Cleaning rollers, cleaning blades, and the like, and image forming apparatus parts used in contact with toner include a developing roller, a toner supply roller, a cleaning roller, a toner layer regulating blade, and a cleaning blade. it can.
[0018]
FIG. 1 is an explanatory view showing an example of an electrophotographic image forming apparatus in which the image forming apparatus component of the present invention is mounted as a transfer roller, and is an image forming body holding a toner supply roller 3 and a latent electrostatic image. The developing roller 2 is disposed with the outer peripheral surface thereof close to the surface of the image forming body 1, and the image forming body 1 is transferred to the image forming body 1 via a recording medium 8 such as paper. A structure in which the roller 5 is brought into contact is shown. By rotating the toner supply roller 3, the developing roller 2, and the image forming body 1 in the direction of the arrow, the toner is supplied to the surface of the developing roller 2 by the toner supply roller 3, and a uniform thin layer is formed by the layer regulating blade 4. Then, the image is adhered to the latent image on the image forming body 1 and the latent image is visualized. The toner image on the image forming body 1 is transferred to the recording medium 8 by generating an electric field between the image forming body 1 and the transfer roller 5. A cleaning roller 6 removes toner remaining on the surface of the image forming body 1 after the transfer. Reference numeral 7 denotes a charging roller.
[0019]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
[0020]
Comparative Example 1
Propylene oxide and ethylene oxide were randomly added to glycerin to produce a polyether polyol having an oxyethylene unit content of 16% by weight, a functional group number of substantially 3, a weight average molecular weight of 5000, and an OH value of 34 mgKOH / g.
50 parts by weight of this polyether polyol, 40 parts by weight of polytetramethylene ether glycol having a weight average molecular weight of 2000 and an OH value of 56 mgKOH / g, 10 parts by weight of polytetramethylene ether glycol having a weight average molecular weight of 1000 and an OH value of 113 mgKOH / g, A mixture of diphenylmethane diisocyanate, urethane-modified diphenylmethane diisocyanate and carbodiimide-modified diphenylmethane diisocyanate, 19.5 parts by weight of a mixed isocyanate component having an isocyanate group content of 26.3% by weight, dimethylpolysiloxane-polyoxyalkylene copolymer 4 parts by weight of a silicone foam stabilizer having an OH value of 32 mg KOH / g, 0.6 parts by weight of ethyl sulfate lauroy liminopropyldimethylethyl ammonium as an electrolyte, and dibutyltin dilaurate 0 0.005 part by weight, 2.5 parts by weight of a black colorant having an OH value of 45 mg KOH / g obtained by dispersing a black pigment in a polyol are mixed while being foamed by mechanical stirring, and the mixture is mixed with a metal shaft having a diameter of 6 mm. After casting into a mold disposed at the center, the resin was heat-cured at 100 ° C. for 10 hours to produce a polyurethane foam roller having a diameter of 16.5 mm and a length of 215 mm. The foam part had a bulk density of 0.40 g / ml, an Asker C hardness of 38 °, an average cell diameter of 130 μm, and a maximum cell diameter of 190 μm.
[0021]
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.21 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^8.15 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The black solid and white solid images were good, but in the gray scale image, the image at the position where the transfer roller was in contact was blackish. Such image disturbance is thought to be due to the occurrence of contamination of the photoreceptor.
About 5 g of the conductive polyurethane of this transfer roller was cut into a small piece of about 3 mm square, extracted with a Soxhlet extractor at 90 ° C. for 8 hours using acetone as an extraction solvent using a cylindrical filter paper, and the extraction rate was 1.8%. (X = 1.8).
[0022]
Here, the amount of the oil-absorbing substance added in Example 1 and Example 2 to be described later will be described. In Examples 1 and 2, the polyurethane member of Comparative Example 1 was blended with light calcium carbonate having an oil absorption of 30 ml / 100 g and magnesium carbonate having an oil absorption of 90 ml / g. As described above, the blending amount Z [wt%] of the non-conductive oil-absorbing substance (mixing ratio in the conductive polyurethane composition) is the extraction rate of the conductive polyurethane when the non-conductive oil-absorbing substance is not added. Weight%], when the oil absorption amount of the non-conductive oil absorbing substance to be added is Y [milliliter / 100 g],
0.1X ≦ 0.01YZ ≦ 7X
In an amount satisfying
0.5 X ≦ 0.01YZ ≦ 4X
In the case of light calcium carbonate having an oil absorption of 30 ml / 100 g in Example 1, when X = 1.8 and Y = 30 are substituted into the above formula, the light calcium carbonate content Z [weight] %]
0.6 ≦ Z ≦ 42.0
Preferably,
3.0 ≦ Z ≦ 24.0
Range. When the blending weight part of light calcium carbonate is calculated from the total blending amount, it is 0.76 to 91.7 parts by weight, and preferably 3.9 to 40.0 parts by weight.
Similarly, in the case of magnesium carbonate having an oil absorption of 90 ml / 100 g in Example 2, when X = 1.8 and Y = 90 are substituted into the above formula, the compounding amount Z [wt%] of magnesium carbonate is
0.2 ≦ Z ≦ 14.0
Preferably,
1.0 ≦ Z ≦ 8.0
Range. When the blending weight part of preferable magnesium carbonate is calculated from the total blending amount, it is 0.25 to 20.6 parts by weight, preferably 1.3 to 11.0 parts by weight.
[0023]
Example 1
Comparative Example 1 was the same as Comparative Example 1 except that 10 parts by weight of light calcium carbonate having an oil absorption of 30 ml / 100 g (Z = about 7.3% by weight, 0.01 YZ = about 2.2) was blended. A roller was produced. The foam portion had a bulk density of 0.43 g / ml, an Asker C hardness of 39 °, an average cell diameter of 120 μm, and a maximum cell diameter of 160 μm.
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.19 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^8.12 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The gray scale, black solid, and white solid images were all good.
[0024]
Example 2
In Comparative Example 1, a roller was prepared in the same manner as in Comparative Example 1 except that 5 parts by weight (Z = about 3.8% by weight, 0.01YZ = about 3.4) of magnesium carbonate having an oil absorption of 90 ml / 100 g was blended. Was made. The foam part had a bulk density of 0.40 g / ml, an Asker C hardness of 41 °, an average cell diameter of 120 μm, and a maximum cell diameter of 160 μm.
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.22 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^8.15 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The gray scale, black solid, and white solid images were all good.
[0025]
Comparative Example 2
In Comparative Example 1, a roller was prepared in the same manner as in Comparative Example 1, except that 100 parts by weight of light calcium carbonate having an oil absorption of 30 ml / 100 g (Z = about 44% by weight, 0.01YZ = about 13.2) was blended. Produced. The foam part had a bulk density of 0.56 g / ml, an Asker C hardness of 47 °, an average cell diameter of 110 μm, and a maximum cell diameter of 150 μm.
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.55 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^8.32 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The gray scale, black solid, and white solid images were all good. However, since the viscosity of the polyurethane composition was high, the process speed had to be half that of Examples 1 and 2, and it was recognized that the production efficiency was lowered.
[0026]
Comparative Example 3
Comparative Example 1 was the same as Comparative Example 1 except that 0.5 parts by weight of light calcium carbonate having an oil absorption of 30 ml / 100 g (Z = about 0.39% by weight, 0.01YZ = about 0.12) was blended. Thus, a roller was produced. The foam part had a bulk density of 0.40 g / ml, an Asker C hardness of 38 °, an average cell diameter of 130 μm, and a maximum cell diameter of 190 μm.
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.21 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^8.15 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The black solid and white solid images were good, but in the gray scale image, the image at the position where the transfer roller was in contact was blackish. However, it was recognized that the degree of the image defect was considerably improved as compared with Comparative Example 1.
[0027]
Comparative Example 4
A roller was produced in the same manner as in Comparative Example 1 except that 5 parts by weight of HAF grade oil furnace black (conductive oil-absorbing substance) having an oil absorption of 100 ml / 100 g was blended. The foam part had a bulk density of 0.39 g / ml, an Asker C hardness of 43 °, an average cell diameter of 120 μm, and a maximum cell diameter of 160 μm.
The roller was placed on an aluminum plate having a thickness of 5 mm, and the electrical resistance between the cored bar and the copper plate was measured while pressing both ends of the roller with a force of 500 g. The temperature and humidity at the time of measurement were 23 ° C. and 50%, respectively. The electrical resistance is 10 when the applied voltage is 1000V. ^8.03 Ω, with an applied voltage of 1000 V and an electrical resistance of 10 ^6.55 Ω.
The roller was incorporated as a transfer roller in the image forming apparatus shown in FIG. After leaving it for 120 hours in an environment where the temperature and humidity are 40 ° C and 95%, respectively, and leaving it for 48 hours in an environment where the temperature and humidity are 23 ° C and 50%, respectively, print a grayscale, black solid, and white solid image. It was. The black solid image and the gray scale image were poorly transferred, and the white solid image was fogged, and a good image could not be obtained. This is considered to be caused by the voltage dependency of the electrical resistance of the polyurethane member constituting the transfer roller.
[0028]
【The invention's effect】
The conductive polyurethane member of the present invention does not contaminate the photoreceptor or the like, does not fuse with the toner, has low hardness, has extremely low electrical resistance positional variation, and voltage dependency. For example, a charging roller or a developing roller , A roller having elasticity such as a transfer roller, a toner supply roller, and a cleaning roller, a blade having elasticity such as a toner layer regulating blade, and a cleaning blade, and the like.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating an example of an electrophotographic image forming apparatus in which an image forming apparatus component of the present invention is mounted as a transfer roller.
[Explanation of symbols]
1: Image forming body
2: Developing roller
3: Roller for toner supply
4: Layer regulation blade
5: Transfer roller
6: Cleaning roller
7: Charging roller
8: Recording medium

Claims (7)

In a conductive member made of polyurethane imparted with conductivity by adding an electrolyte , the polyurethane member has a trifunctional polyether polyol component and a polyisocyanate component starting from glycerin having a weight average molecular weight of 1500 to 6000. A polyurethane member obtained by mixing and curing a non-conductive oil-absorbing substance, wherein the polyurethane has a non-conductive oil-absorbing substance selected from light calcium carbonate and magnesium carbonate having an oil absorption of 20 to 120 [milliliter / 100 g]. Including the non-conductive oil-absorbing substance blending amount Z [wt%] is the extraction rate of the conductive polyurethane when the non-conductive oil-absorbing material is not added [ extraction rate obtained by Soxhlet extraction with acetone solvent at 90 ° C for 8 hours] X [wt%], and Y [milliliter / If you have a 00g],
0.5 X ≦ 0.01YZ ≦ 4 X
A conductive polyurethane member characterized by satisfying The conductive polyurethane member according to claim 1 , wherein the electrolyte is selected from a quaternary ammonium salt of an alkyl sulfuric acid and a quaternary ammonium salt of a polybasic carboxylic acid. It is constructed using a conductive polyurethane member according to claim 1 or 2, and an image forming apparatus parts used in contact with the photosensitive member. 4. The image forming apparatus component according to claim 3 , wherein the image forming apparatus component used in contact with the photosensitive member is a charging roller, a developing roller, a toner supply roller, a transfer roller, a cleaning roller, or a cleaning blade. Claim 1 or formed by using a conductive polyurethane member 2, and an image forming apparatus parts used in contact with the toner. The image forming apparatus component according to claim 5 , wherein the image forming apparatus component used in contact with the toner is a developing roller, a toner supply roller, a cleaning roller, a toner layer regulating blade or a cleaning blade. An image forming apparatus comprising the image forming apparatus component according to claim 3 .

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