JP2019082586A - Composition for cleaning blade, and cleaning blade - Google Patents

Abstract

To provide a composition for a cleaning blade and the cleaning blade that restrict image failure during subsequent printing by eliminating electric potential unevenness on a photoreceptor surface after a printing process, while maintaining a cleaning function.SOLUTION: Provided is a thermosetting composition for a cleaning blade to be used in forming a rubber elastic body 12 of a cleaning blade 10 for an electrophotographic apparatus comprising the rubber elastic body 12. The composition for the cleaning blade contains: (a) a polyester polyol; (b) a polyisocyanate; (c) a modified polyamide; and (d) a urethanization catalyst. The (c) includes an N-substituted amide group which forms a crosslinking point when thermosetting the composition for the cleaning blade.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composition for cleaning blades for electrophotographic devices and a cleaning blade for electrophotographic devices.

  In electrophotographic apparatuses such as copying machines, printers, and facsimiles that employ the electrophotographic method, potential unevenness is caused on the surface of the photosensitive member after the printing process due to the electric charge related to the printed image. In order to eliminate such potential unevenness, the electrophotographic apparatus is provided with a static elimination mechanism. On the other hand, there is a proposal for an electrophotographic apparatus which does not have such a charge removal mechanism, from the demand for cost reduction and compactness of the electrophotographic apparatus. However, in an electrophotographic apparatus which does not have a discharging mechanism, the above-mentioned potential unevenness can not be sufficiently eliminated in the next charging process, and as a result of the next printing being performed with the above-mentioned potential unevenness, the previous image Dragged images (ghost images) are printed, and image defects are likely to occur.

  On the other hand, for example, Patent Document 1 proposes a cleaning blade for removing the toner remaining on the surface of the photosensitive member, which also serves as a charge removing unit, and does not require any other charge removing mechanism. According to Patent Document 1, it is described that a cleaning blade mixes a polymer material such as polyurethane with a metal such as aluminum oxide or a conductive material such as carbon to have a predetermined resistance value.

Unexamined-Japanese-Patent No. 05-265362 Japanese Patent Application Publication No. 06-118858

  In the cleaning blade of Patent Document 1, the resistance uniformity is not sufficient in terms of the dispersibility of the conductive material, and the above-mentioned potential unevenness can not be eliminated, and the image failure can not be suppressed.

  Patent Document 2 describes a cleaning blade composed mainly of a thermoplastic polymer blend of polyurethane and polyamide. However, the cleaning blade of Patent Document 2 is not used as a static elimination unit in order to eliminate the above-mentioned potential unevenness. Further, with the cleaning blade of Patent Document 2, the above-mentioned potential unevenness can not be eliminated in terms of the dispersibility of polyamide, etc., and image defects can not be suppressed.

  The problem to be solved by the present invention is a composition for cleaning blade and a cleaning blade that can eliminate potential unevenness at the time of next printing by eliminating potential unevenness on the surface of the photosensitive member after the printing process while maintaining the cleaning function. It is to provide.

  In order to solve the above problems, a composition for a cleaning blade according to the present invention is a composition for a thermosetting cleaning blade used for forming the rubber elastic body of a cleaning blade for an electrophotographic apparatus having a rubber elastic body, And (a) polyester polyol, (b) polyisocyanate, (c) modified polyamide, and (d) urethanization catalyst, wherein (c) forms a crosslinking point upon heat curing of the composition for a cleaning blade. The gist of the present invention is to have an N-substituted amido group.

  The N-substituent of the N-substituted amido group is preferably any one or two or more of an N-alkoxyalkyl group and an N-alkyl group. The content of the N-substituted amido group in the (c) is preferably in the range of 20 to 50 mol% with respect to the total amount of the amido group in the (c). It is good for content of said (c) to exist in the range of 0.5-20 mass parts with respect to 100 mass parts of said (a). The N-substituent of the N-substituted amido group is preferably an N-methoxymethyl group.

  And the cleaning blade which concerns on this invention makes it a summary to have a rubber elastic body which consists of hardened | cured material of the composition for cleaning blades of any one of said one.

  According to the composition for a cleaning blade according to the present invention, since the polyamide having a N-substituted amide group is contained, the electrostatic capacity of the rubber elastic body of the cleaning blade is increased, and the rubber elastic body of the cleaning blade has a static elimination effect. Can be demonstrated. As a result, even in the electrophotographic apparatus which is not provided with the charge removing mechanism, the charge removing action by the rubber elastic body of the cleaning blade eliminates the potential unevenness on the surface of the photosensitive member after the printing process while maintaining the cleaning function. You can suppress image problems in And since this polyamide forms a crosslinking point at the time of thermosetting of the composition for cleaning blades, since polyamide disperses uniformly at a molecular level, the rubber elastic body of a cleaning blade can exhibit a static elimination effect uniformly. it can.

  And, when the N-substituent of the N-substituted amido group is an N-alkoxyalkyl group, the solubility in alcohol is improved and it can be added to the composition as an alcohol solution, so the composition for cleaning blade Dispersion in the And, when the content of the N-substituted amido group is in the range of 20 to 50 mol% with respect to the total amount of the amido group in (c), the effect of increasing the electrostatic capacity of the rubber elastic body Excellent balance of effects of maintaining And if the content of (c) is in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of (a), the effect of increasing the electrostatic capacity of the rubber elastic body and the flexibility of the rubber elastic body Excellent balance of maintaining effects.

  And, according to the cleaning blade according to the present invention, since the rubber elastic body made of the cured product of the composition for cleaning blade according to the present invention is used, rubber elasticity of the cleaning blade can be obtained By the static elimination action by the body, the potential unevenness on the surface of the photosensitive member after the printing process is eliminated while maintaining the cleaning function, and the image failure at the time of the next printing can be suppressed.

It is a schematic diagram of the cleaning blade which concerns on one Embodiment of this invention. FIG. 5 is a schematic view showing how the cleaning blade according to the embodiment of the present invention slides on the outer peripheral surface of the rotating photosensitive drum.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a cleaning blade (hereinafter sometimes referred to as a main blade) according to an embodiment of the present invention, and FIG. 2 shows the cleaning blade sliding on the outer peripheral surface of a photosensitive drum. It is the schematic diagram which showed.

  As shown in FIG. 1, a cleaning blade (main blade) 10 according to an embodiment of the present invention includes a rubber elastic body 12. The rubber elastic body 12 has a flat plate shape. The rubber elastic body 12 is attached with a holding portion 14 for holding the rubber elastic body 12. The holding portion 14 is made of, for example, a metal fitting having an L-shaped cross section. The rubber elastic body 12 contacts (slids with) the other member at a portion including the tip end portion (ridge line portion) 12a. The portion including the tip end portion (ridge portion) 12 a is the contact portion.

  The blade 10 is suitable as a cleaning blade in an electrophotographic apparatus. A photosensitive member (photosensitive drum) may be mentioned as the counterpart of the cleaning blade. The cleaning blade contacts (slids with) the other member to remove the residual toner. For example, as shown in FIG. 2, the rubber elastic body 12 contacts the outer peripheral surface 20a of the photosensitive drum 20 at a portion including the tip portion (ridge line portion) 12a and slides on the outer peripheral surface 20a of the rotating photosensitive drum 20 Do. Thus, the toner remaining on the outer peripheral surface 20 a of the photosensitive drum 20 is removed.

  The composition for a cleaning blade according to the present invention (hereinafter sometimes referred to as the present composition) is a thermosetting composition for a cleaning blade used for forming the rubber elastic body 12 of the present blade 10. The composition contains (a) polyester polyol, (b) polyisocyanate, (c) modified polyamide, and (d) urethanization catalyst.

  The polyester polyol (a) is not particularly limited as long as it is a polyester polyol for forming a urethane rubber used to form a urethane rubber.

  The polyester polyol is obtained from a polybasic organic acid and a low molecular weight polyol, and one having a hydroxyl group as an end group can be mentioned as a preferable one. The polybasic organic acid is not particularly limited, and is a saturated fatty acid such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isosebacic acid, maleic acid, Unsaturated fatty acids such as fumaric acid, dicarboxylic acids such as aromatic acids such as phthalic acid, isophthalic acid and terephthalic acid, acid anhydrides such as maleic anhydride and phthalic anhydride, dialkyl esters such as dimethyl terephthalate, and unsaturated fatty acids And dimer acids obtained by dimerization of The low molecular weight polyol to be used together with the polybasic organic acid is not particularly limited. For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, 1, 6 -Diols such as hexylene glycol, trimethylol ethane, trimethylol propane, hexane triol, triols such as glycerin, hexaols such as sorbitol, and the like.

  Specific examples of polyester polyols include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylen adipate (PHA), polycaprolactone, a copolymer of ethylene adipate and butylene adipate (PEA / BA), etc. Can be mentioned as more preferable. One of these polyester polyols may be used alone, or two or more thereof may be used in combination. Among these, polybutylene adipate (PBA) is particularly preferable from the viewpoint of the abrasion resistance, durability, hydrolysis resistance and the like of the rubber elastic body 12.

  The number average molecular weight (Mn) of the polyester polyol is not particularly limited, but a range of 1000 to 3000 is preferable. While low viscosity and excellent in moldability, physical properties are easily secured. From this viewpoint, the number average molecular weight is more preferably in the range of 1,500 to 2,500.

  The polyisocyanate (b) is not particularly limited as long as it is a polyisocyanate for forming a urethane rubber used to form a urethane rubber. As such polyisocyanate, diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (polymeric MDI), crude MDI (c-MDI) which is a mixture of MDI and polymeric MDI, dicyclohexylmethane diisocyanate (hydrogenated MDI), tri Di-isocyanate (TDI), hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), isophorone diisocyanate (IPDI), ortho-toluidine diisocyanate (TODI), naphthyl diisocyanate (NDI), xylene diisocyanate (XDI), para-phenylene diisocyanate (PDI), lysine diisocyanate methyl ester (LDI), dimethyl Isocyanate (DDI), MDI cyanurate is multimeric, HDI isocyanurate, TDI isocyanurate, these urea reduction, biuret reduction, allophanatization, carbodiimidization, like the modified products such as urethanization. Further, as the (b) polyisocyanate, an NCO-terminated urethane prepolymer obtained by reacting a polyisocyanate such as MDI described above and a polyester polyol for forming a urethane rubber mentioned as the (a) polyester polyol may be used. These may be used individually by 1 type as polyisocyanate (b), and may be used in combination of 2 or more types. Among them, MDI, polymeric MDI, crude MDI, modified MDI (urea formation, buret formation, allophanate formation, carbodiimidization, urethane formation MDI, etc.), NCO end, etc. from the viewpoints of ease of handling, availability, cost, etc. Urethane prepolymers are more preferred.

(B) The urethane prepolymer as the polyisocyanate has an NCO% within the range of 5 to 30% by mass from the viewpoint of low viscosity and excellent moldability, and the tendency of urethane formation reaction at the time of prepolymer formation to progress uniformly. Is preferred. NCO% is calculated by the following equation.

  The compounding amount of (b) polyisocyanate in the present composition is such that NCO index (isocyanate index) is 110 or more from the viewpoint of easy improvement of the abrasion resistance of rubber elastic body 12, easy securing of strength, resistance to setback, etc. It is preferable to set so that The NCO index is more preferably 115 or more, further preferably 120 or more, 125 or more, 130 or more. On the other hand, it is preferable to set the NCO index to 250 or less from the viewpoint of the rubber elastic body 12 not becoming too hard, satisfying the cleaning property at low temperature, and being easy to form. The NCO index is more preferably 200 or less, still more preferably 180 or less. The NCO index is calculated as the equivalent of isocyanate group to the total equivalent 100 of active hydrogen groups (hydroxyl group, amino group, etc.) that react with isocyanate group.

  (C) The modified polyamide is a polyamide having an N-substituted amido group. By containing a polyamide having an N-substituted amido group, the electrostatic capacity of the rubber elastic body 12 of the present blade 10 obtained from the present composition is increased, and the rubber elastic body 12 of the present blade 10 exerts a diselectrification effect be able to. Moreover, since it has an N-substituted amido group, the (c) modified polyamide can form a crosslinking point at the time of heat curing of the present composition. Thereby, since the polyamide is uniformly dispersed at the molecular level in the present composition, the rubber elastic body 12 of the present blade 10 obtained from the present composition can exhibit a static elimination effect uniformly. In addition, the surface of the rubber elastic body 12 can be uniformly made to have high hardness, and the cleaning property is improved. In addition, since the cross-linking can also suppress bleeding of the polyamide over time, a change in capacitance during endurance can be suppressed. Thereby, it is excellent also in the static elimination effect after endurance.

  (C) Examples of the N-substituent of the N-substituted amido group of the modified polyamide include an N-alkoxyalkyl group and an N-alkyl group. These may be possessed singly or in combination of two or more as the N-substituent of the N-substituted amido group of the (c) modified polyamide. Among these, an N-alkoxyalkyl group is more preferable. When the N-substituent of the N-substituted amido group is an N-alkoxyalkyl group, the solubility in alcohol is improved, and it can be added to the composition as an alcohol solution, so dispersion in the composition for cleaning blade Improves the quality.

  From the viewpoint of crosslinking strength and the like, as the N-alkoxyalkyl group, an alkoxy group having 1 to 4 carbon atoms and an alkyl group having 1 to 4 carbon atoms is more preferable. As such an N-alkoxyalkyl group, an N-methoxymethyl group, an N-ethoxymethyl group, an N-butoxymethyl group and the like can be mentioned. As the N-alkyl group, an alkyl group having 1 to 4 carbon atoms is more preferable from the viewpoint of crosslinking strength and the like. As such an N-alkyl group, an N-methyl group, an N-ethyl group, an N-propyl group, an N-butyl group and the like can be mentioned.

  The content of the N-substituted amido group in the (c) modified polyamide is preferably in the range of 20 to 50 mol% with respect to the total amount of the amido group in (c). More preferably, it is in the range of 25 to 40 mol%. When the content of the N-substituted amide group is 20 mol% or more, the effect of increasing the capacitance of the rubber elastic body 12 of the blade 10 is excellent. Moreover, it is excellent in the effect of maintaining the softness | flexibility of the rubber elastic body 12 as content of N- substituted amido group is 50 mol% or less. By being excellent in flexibility, chipping of the rubber elastic body 12 at the time of cleaning can be easily suppressed. The total amount of the amide group in (c) can be measured by acid-base titration method (Boehm method). The content of the N-substituted amido group can be measured by "Alkoxyl group determination device (decomposition agent: hydrogen iodide, catalyst: acetic acid" manufactured by Asahi Manufacturing Co., Ltd.

  The content of the (c) modified polyamide in the present composition is preferably in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of (a). More preferably, it is in the range of 1.0 to 15 parts by mass, and more preferably in the range of 2.0 to 10 parts by mass. When the content of the modified polyamide (c) is 0.5 parts by mass or more with respect to 100 parts by mass of (a), the effect of increasing the capacitance of the rubber elastic body 12 of the blade 10 is excellent. Moreover, it is excellent in the effect of maintaining the softness | flexibility of the rubber elastic body 12 as content of modified polyamide (c) is 20 mass parts or less with respect to 100 mass parts of (a). By being excellent in flexibility, chipping of the rubber elastic body 12 at the time of cleaning can be easily suppressed. Moreover, it is easy to ensure rubber elasticity at low temperature (for example, 0 ° C.). By being excellent in rubber elasticity at a low temperature, it is easy to suppress the toner slip through at the time of cleaning at a low temperature.

  (D) A urethanization catalyst is a catalyst used as a catalyst which promotes a urethanation reaction. The catalyst is not particularly limited, and examples thereof include amine compounds such as tertiary amines and organic metal compounds such as organic tin compounds. Examples of tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N, N, N ', N'-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, and ethoxyl. Esterified amines, ethoxylated diamines, ester amines such as bis (diethylethanolamine) adipate, cyclohexylamine derivatives such as triethylenediamine (TEDA), N, N-dimethylcyclohexylamine, N-methylmorpholine, N- (2-hydroxypropyl) And morpholine derivatives such as dimethylmorpholine; and piperazine derivatives such as N, N'-diethyl-2-methylpiperazine and N, N'-bis- (2-hydroxypropyl) -2-methylpiperazine. Further, as the organic tin compound, for example, dialkyltin compounds such as dibutyltin dilaurate, dibutyltin di (2-ethylhexoate) and the like, tin 2-ethyl caproate, tin tin oleate and the like can be mentioned. . These may be used alone or in combination of two or more. Among these, triethylenediamine (TEDA) is preferably used from the viewpoints of being difficult to hydrolyze and having less contamination by bleeding.

  The content of the (d) urethanization catalyst in the present composition is not particularly limited as long as it appropriately promotes the urethanation reaction. For example, the inside of the range of 0.01-5 mass parts is preferable with respect to 100 mass parts of (a). More preferably, it is in the range of 0.1 to 3 parts by mass.

  The present composition may contain other components in addition to (a) to (d). Other components include chain extenders, crosslinking agents, surfactants, flame retardants, colorants, plasticizers, mold release agents and the like. Also, the composition may or may not contain a conductive agent. Examples of the conductive agent include ion conductive agents such as imidazolium salts, pyridinium salts, ammonium salts, phosphonium salts, sulfonium salts, borates, metal salts and surfactants, and electron conductive agents such as carbon black.

  The chain extender is a bifunctional compound capable of reacting with polyurethane, such as diol or diamine. The low molecular weight one having a number average molecular weight of 300 or less is preferable. As a chain extender, 1,4-butanediol (1,4-BD), ethylene glycol (EG), 1,6-hexanediol (1,6-HD), diethylene glycol (DEG), propylene glycol (PG) , Dipropylene glycol (DPG), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylene glycol, diols such as triethylene glycol, and 2,2 ', 3,3'-tetrachloro-4,4 '-Diaminodiphenylmethane, 3,3'-dichloro-4,4'-diphenylmethane, trimethylene-bis (4-aminobenzoate), 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane And aromatic diamines and the like. These may be used singly or in combination of two or more. Among these, 1,4-butanediol (1,4-BD), ethylene glycol (EG), 1,6-hexanediol (1,1) from the viewpoints of securing physical properties and easy improvement of moldability. 6-HD) is preferable.

  The crosslinking agent is a trifunctional or higher functional compound such as triol or triamine capable of reacting with the polyurethane. The low molecular weight one having a number average molecular weight of 300 or less is preferable. Crosslinking agents include trimethylolpropane (TMP), glycerin, pentaerythritol, sorbitol, 1,2,6-hexanetriol and the like. These may be used singly or in combination of two or more. Among these, trimethylolpropane (TMP) and the like are preferable from the viewpoints of securing of physical properties and easy improvement of moldability.

  The rubber elastic body 12 of the blade 10 can be produced by injecting the present composition into a predetermined molding die and molding it. The cast molding can be performed according to the prepolymer method, the semi one shot method, the one shot method. The semi one-shot method is preferred because of its excellent processability. In the semi one-shot method, a urethane prepolymer (main agent liquid) is prepared from polyisocyanate and polyol, and (a) polyol, (d) urethanization catalyst, if necessary, chain extender, crosslinking agent, etc. are blended. A curing agent solution is prepared, and a main agent solution, a curing agent solution, and (c) modified polyamide are mixed at a predetermined ratio to form the present composition, and the present composition is injected into a molding die and reacted and cured. The rubber elastic body 12 having a predetermined shape can be manufactured. The holding portion 14 is integrated with the rubber elastic body 12 by partially burying the rubber elastic body 12 at the time of molding, or by adhering to a predetermined position using an adhesive after the rubber elastic body 12 is molded. It can be done.

  The molding temperature of the present composition is preferably set to a relatively high temperature so that (c) the modified polyamide forms a crosslinking point upon heat curing of the present composition. For example, the molding temperature of the present composition is preferably 140 ° C. or higher. More preferably, it is 150 ° C. or higher.

  The modified polyamide (c) is preferably mixed in a liquid state with the main agent liquid and the curing agent liquid from the viewpoint of improving the dispersibility in the present composition. (C) When a modified polyamide in which the N-substituent of the N-substituted amido group is an N-alkoxyalkyl group is used as the modified polyamide, the solubility in alcohol is improved and it can be added to the composition as an alcohol solution As a result, the dispersibility in the present composition is improved. Examples of the alcohol as a solvent include methanol and ethanol.

  According to the composition of the above configuration, since the polyamide having the N-substituted amide group is contained, the electrostatic capacity of the rubber elastic body 12 of the blade 10 obtained from the composition becomes large, and the blade 10 The rubber elastic body 12 can exert the charge removing effect. Thus, even when the charge removing mechanism is not provided, the charge removing action by the rubber elastic body 12 of the blade 10 maintains the cleaning function while eliminating the potential unevenness on the surface of the photosensitive member after the printing step, and at the time of the next printing. The occurrence of an image (ghost image) that drags the previous image is suppressed, and image defects are suppressed. And since this polyamide forms a crosslinking point at the time of thermosetting of this composition, since polyamide disperses uniformly at a molecular level, rubber elastic body 12 of this blade 10 obtained from this composition is uniform. It is possible to exert the diselectrification effect. Further, since the polyamide is uniformly dispersed at the molecular level in the rubber elastic body 12, the surface of the rubber elastic body 12 can be uniformly made to have a high hardness, and the cleaning property is improved. In addition, since the cross-linking can also suppress bleeding of the polyamide over time, a change in capacitance during endurance can be suppressed. Thereby, it is excellent also in the static elimination effect after endurance.

  Then, in the rubber elastic body 12 of the blade 10 made of the cured product of the present composition, the N-substituent of the modified polyamide of (c) is a crosslinking point, and the modified polyamide is crosslinked. Cross-linking of the modified polyamide in the rubber elastic body 12 can be confirmed qualitatively and quantitatively by an extraction method using a solvent. For example, when the modified polyamide is an N-alkoxyalkylated nylon, the solubility in alcohol is high, and the non-crosslinked product is extracted from the rubber elastic body 12 with alcohol, while the crosslinked product is not extracted from the rubber elastic body 12 with alcohol. It can be confirmed qualitatively and quantitatively that the modified polyamide is crosslinked in the rubber elastic body 12 by utilizing this.

  Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to this configuration.

Details of the materials used in the following cleaning blade compositions are given below. The composition for cleaning blade is a thermosetting composition used for forming a rubber elastic body of a cleaning blade for electrophotographic apparatus.
・ PBA (polybutylene adipate): Nippon Polyurethane Industry "Nipporan 4010"
・ MDI (4,4'-diphenylmethane diisocyanate): Nippon Polyurethane Industry "Millionate MT"
TMP (trimethylolpropane): manufactured by Mitsubishi Gas Chemical 1,4 BD (1,4-butanediol): manufactured by Mitsubishi Chemical TEDA (triethylenediamine): manufactured by Tosoh Polyamide <1>: N-methoxymethylated nylon ( Lead resin "Fine resin FR-104", N-methoxymethyl group content: 30 mol% with respect to the total amount of amide groups)
-Polyamide <2>: N-ethoxymethylated nylon (product manufactured in-house, content of N-ethoxymethyl group: 30 mol% with respect to the total amount of amide groups)
In a three-neck flask equipped with an airtight stirrer, reflux condenser, and thermometer, add benzene-washed nylon 6 and acetaldehyde containing methanol and oxalic acid catalyst, and react it in an oil bath set at 75 ° C for 2 hours. After that, the reaction product was washed with water and air-dried.
-Polyamide <3>: non-modified nylon (manufactured by Unitika "Unitika nylon 6 A1030 BRL")

(Examples 1 to 6)
<Preparation of composition for cleaning blade>
PBA (75 parts by mass) and MDI (50 parts by mass) were mixed and reacted at 65 ° C. for 240 minutes under a nitrogen atmosphere to prepare a main agent (NCO-terminated urethane prepolymer, NCO% = 15 mass%). In addition, a curing agent (hydroxyl value 200 (KOH mg) is obtained by mixing PBA (25 parts by mass) and a low molecular weight polyol in which 1,4 BD and TMP are mixed at a mass ratio of 3: 5 at 85 ° C. for 60 minutes. / G) was prepared. Next, the main agent and the curing agent are blended so that the NCO index is 120 to 200, and a methanol solution (solid content concentration 20 mass%) of a modified polyamide (polyamide <1> or polyamide <2>) and a urethanization catalyst The composition for cleaning blades which consists of the urethane composition which modified polyamide disperse | distributed was prepared by mix | blending TEDA as and mixing for 10 minutes at 80 degreeC under nitrogen atmosphere. The compounding ratio (parts by mass) of each component is as described in Table 1. It is shown by a mass ratio to a total of 100 parts by mass of PBA used for the main agent and the curing agent.

<Preparation of Cleaning Blade>
After placing the plate-like holder in the mold of the cleaning blade and injecting the prepared composition for cleaning blade into the mold, the mold is heated to 155 ° C. to cure the composition for the cleaning blade for 15 minutes. By removing the mold and cutting, a cleaning blade in which the rubber elastic body and the plate-like holder (holding portion) were integrated was produced.

(Comparative example 1)
In the preparation of the composition for cleaning blade, preparation of the composition for cleaning blade and preparation of the cleaning blade were performed in the same manner as in Example 1 except that the modified polyamide was not blended.

(Comparative example 2)
Preparation of composition for cleaning blade and preparation of cleaning blade were carried out in the same manner as in Example 1 except that non-modified polyamide (polyamide <3>) was used instead of modified polyamide in preparation of composition for cleaning blade. The

(Comparative example 3)
<Preparation of Cleaning Blade>
Pellet-shaped thermoplastic polyurethane and pellet-shaped thermoplastic polyamide are introduced into the hopper at the mixing ratio (parts by mass) described in Table 1, melted in the heating section and blended, and a cleaning blade having a plate-shaped holder arranged The cleaning blade was manufactured by extruding into a mold of
Thermoplastic polyurethane: "Milactoran P485 RSUI" manufactured by Tosoh Corporation
Thermoplastic polyamide: “Zytel ST811HS” manufactured by DuPont

(Comparative example 4)
In the preparation of the composition for cleaning blade, in the same manner as in Example 1 except that the conductive agent (carbon black) is compounded in the amount (parts by mass) described in Table 1 without compounding modified polyamide, for cleaning blade Preparation of the composition and preparation of a cleaning blade were performed.

  For each of the produced cleaning blades, the measurement of the capacitance of the rubber elastic body portion and the image evaluation (ghost image, streak image) were performed. The evaluation results are shown in the following table.

(Measurement of capacitance)
A sheet material having a thickness of 2 mm was obtained from the rubber elastic body portion of the produced cleaning blade. By applying silver paste on one surface of the obtained sheet material, an electrode having a size of 10 × 10 mm was provided (with a guard electrode). On the other hand, a counter electrode was provided on the side opposite to the side on which the electrode was provided. Using a LCZ meter (4276A manufactured by YHP), the capacitance C [pF] was measured under the conditions of no DC application, an AC applied voltage of 1 V, and a frequency of 1 kHz under an environment of 25 ° C. and 50% RH.

(Ghost image)
Install the created cleaning blade into a commercially available laser printer ("LaserJet Enterprise Color M 552 dn" manufactured by HP), and visually check the image quality of the image after outputting 5,000 sheets in A4 size in a low temperature environment (0 ° C) evaluated. Under the present circumstances, the case where a ghost image was not recognized is "◎", the case where a ghost image was recognized but very slight was "○", the case where a ghost image was recognized but acceptable to an acceptable degree was "「 " The case where a ghost image was clearly recognized was taken as "x". There is no other charge removal mechanism provided in the used laser printer.

(Stripe image: Slip through)
Install the created cleaning blade into a commercially available laser printer ("LaserJet Enterprise Color M 552 dn" manufactured by HP), and visually check the image quality of the image after outputting 5,000 sheets in A4 size in a low temperature environment (0 ° C) evaluated. At this time, "◎" when no streak due to toner slippage was observed, "認 め" when streak was recognized but extremely slight, "○", when streak was recognized but acceptable as "△" When the line was clearly recognized, it was regarded as "x".

(Stripe image: Missing)
Install the created cleaning blade into a commercially available laser printer ("LaserJet Enterprise Color M 552 dn" manufactured by HP), and visually check the image quality of the image after outputting 5,000 sheets in A4 size in a low temperature environment (0 ° C) evaluated. At this time, if no streaks were observed due to a partial lack of the cleaning blade, "「 ", if streaks were observed but if very slight," ○ ", streaks were recognized but acceptable. Minor cases were marked as "△", and cases where streaks were clearly recognized as "x".

  According to the examples and the comparative examples, when the composition for cleaning blade contains a polyamide having an N-substituted amido group, the electrostatic capacity of the rubber elastic body becomes large, and the rubber elastic body exerts a diselectrification effect. Can. Thus, it can be seen that the occurrence of ghost images can be suppressed even when no other charge removal mechanism is provided. Further, according to the embodiment, it can be seen that generation of streak images due to chipping of the rubber elastic body and toner slip-through can be suppressed. That is, the cleaning function can be maintained.

  The comparative example 1 does not contain polyamide in the composition for cleaning blades. Therefore, the occurrence of ghost images can not be suppressed. In Comparative Example 2, the composition for the cleaning blade contains a polyamide but is a non-modified polyamide. Therefore, the effect of suppressing the occurrence of ghost images is smaller than that of the modified polyamide. In addition, since non-modified polyamide has no chemical bond with polyurethane, its physical properties are different from the viewpoint of non-denatured polyamide from the viewpoint of micro view. The point where polyamide is not present is softer than the point where it is present, so the toner tends to slip through, resulting in the occurrence of streak images. Therefore, the cleaning function can not be maintained. In Comparative Example 3, the cleaning blade composition comprises a mixture of a thermoplastic polyurethane and a thermoplastic polyamide. It is not possible to eliminate the potential unevenness on the surface of the photosensitive drum due to the dispersibility of polyamide, etc., and the generation of ghost images can not be suppressed. The comparative example 4 does not contain polyamide in the composition for cleaning blades. Instead, an electronic conductive agent is included. In Comparative Example 4, the resistance uniformity is not sufficient in terms of the dispersibility of carbon black, and the potential unevenness on the surface of the photosensitive drum can not be eliminated, and the occurrence of ghost images can not be suppressed.

  As mentioned above, although embodiment of this invention was described in detail, this invention is not limited at all to the said Example, A various change is possible in the range which does not deviate from the summary of this invention.

10 cleaning blade 12 rubber elastic body 14 holding portion

Claims (6)

A thermosetting cleaning blade composition for use in forming the rubber elastic body of an electrophotographic cleaning blade having a rubber elastic body, comprising:
(A) polyester polyol (b) polyisocyanate (c) modified polyamide (d) containing a urethanization catalyst,
A composition for a cleaning blade, wherein (c) has an N-substituted amido group which forms a crosslinking point when the composition for a cleaning blade is thermally cured.   The composition for a cleaning blade according to claim 1, wherein the N-substituent of the N-substituted amido group is one or more of N-alkoxyalkyl group and N-alkyl group. .   Content of the said N-substituted amido group in said (c) is in the range of 20-50 mol% with respect to the total amount of the amide group of said (c), It is characterized by the above-mentioned. Composition for cleaning blades.   The content of said (c) is in the range of 0.5-20 mass parts with respect to 100 mass parts of said (a), The cleaning of any one of Claim 1 to 3 characterized by the above-mentioned Composition for blades.   The composition for a cleaning blade according to any one of claims 1 to 4, wherein the N-substituent of the N-substituted amido group is an N-methoxymethyl group.   A cleaning blade comprising a rubber elastic body formed of a cured product of the composition for a cleaning blade according to any one of claims 1 to 5.

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