JP2009080167A - Manufacturing method for urethane blade member for electrophotographic image forming apparatus, and the urethane blade member for electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, whereby an urethane blade member in which the ability to scrape toner is enhanced can be manufactured advantageously with satisfactory workability, without causing emission of abnormal sound, chipping of an edge, and so on, and also to provide an urethane blade member capable of sliding over a photoreceptor with sufficient pressing force, thereby preventing escape of toner, and capable of advantageously preventing wearing or chipping of a sliding part, moreover without causing abnormal sounds. <P>SOLUTION: A curing catalyst made of a polyurethane rubber material is applied or sprayed onto the internal surface of at least a molding die, which forms an edge 20 for the urethane blade member 10, which is slid over the circumferential face 18 of a photoreceptor 16, and thereafter, by having a polyurethane rubber material injected into the molding cavity of the molding die and cured, the urethane blade member 10, in which low hardness portion 24 is formed, is manufactured for the electrophotographic image forming apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a urethane blade member for an electrophotographic image forming apparatus for removing toner remaining without being transferred to the outer peripheral surface of a photoreceptor of the electrophotographic image forming apparatus, and for the electrophotographic image forming apparatus. The present invention relates to a urethane blade member.

  2. Description of the Related Art Conventionally, a cleaning blade is attached to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine thereof. Such a cleaning blade is generally a blade made of an elastic material that is brought into sliding contact with the outer peripheral surface of the photosensitive member, and the blade is attached to a cleaning device or the like built in the electrophotographic image forming apparatus while holding the blade. A holding member made of a metal plate or the like, and the edge portion of the blade constituting such a cleaning blade is brought into sliding contact with the outer peripheral surface of the photosensitive member, whereby the photosensitive member is transferred after the toner image is transferred. The toner remaining on the outer peripheral surface is scraped off and removed.

  In order to improve the scraping property of the toner remaining on the surface of the photoconductor and reliably remove the residual toner, the fine toner of several μm to several tens of μm remaining on the surface of the photoconductor does not slip through the blade. In addition, it is necessary to bring the blade made of the elastic material into sliding contact with the surface of the photosensitive member with a high pressing force. For this reason, measures for increasing the hardness of the elastic material constituting the blade have been conventionally taken. However, if the hardness of the entire elastic material is increased too much, abnormal noise (squeaking) may occur due to sliding contact between the blade and the photoconductor, or the outer peripheral surface of the photoconductor may be damaged, or high pressure may be applied. By pressing with force, the pressing force against the blade from the photoconductor also increases, and the blade tends to wear out and the sliding contact part (especially the edge part) tends to chip. As a result, there was a problem that poor cleaning was caused. On the other hand, if the hardness of the entire elastic material constituting the blade is lowered, the pressing force to the photosensitive member is lowered and the generation of abnormal noise can be suppressed, but the scraping property of the toner is lowered and the residual toner is reduced. There is a problem that the blade easily slips through and causes an image defect, and a problem that the sliding contact portion is chipped due to the softness of the entire blade. For this reason, the blade member capable of satisfying contradictory conditions, i.e., can prevent the toner from slipping out without causing abnormal noise or damage to the photosensitive member, and can be applied to the sliding contact portion by the pressing resistance from the photosensitive member. There is a need for a blade member that does not cause wear or chipping.

  Further, as an elastic material constituting the blade of the cleaning blade as described above, conventionally, a polyurethane rubber material having excellent properties such as wear resistance has been widely used. However, there is a strong tendency to resinize at low temperatures (higher hardness and deteriorate elasticity), to rubberize at higher temperatures (lower hardness and excessive elasticity), and the toner scraping property varies greatly depending on the temperature environment used. . On the other hand, in recent years, with the diversification of the usage environment of electrophotographic image forming apparatuses such as printers, the blade member is good in a wide temperature range from a low temperature (about 10 ° C.) to a high temperature (about 32 ° C.). It has also been requested to ensure a good toner scraping property.

  Under such circumstances, Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-3882) discloses that a JIS A hardness at 23 ° C. is 50 ° to 65 ° as an elastic rubber member (blade) constituting a cleaning blade for an electrophotographic apparatus. A two-layer structure of an edge layer made of a material and a base layer made of a material having a JIS A hardness of 70 ° to 99 ° at 23 ° C. has been clarified. It has been clarified that the use of the member can prevent the toner remaining on the surface of the image carrier from slipping through. In such a document, in order to form such a two-layer elastic rubber member, two types of different polyurethane rubber raw materials are used, and after forming a low hardness edge layer with one of the raw materials, We have proposed a method of stacking and forming a base layer with high hardness using the other raw material. However, in such a method, the edge layer and the base layer must be formed sequentially, which makes the work complicated. It was difficult to say that workability was good. In addition, since the edge layer and the base layer are formed using different raw materials, depending on the combination of the polyurethane rubber raw materials used, there is a risk that peeling is likely to occur at the interface between the edge layer and the base layer. There was room for further improvement.

Japanese Patent Laid-Open No. 2007-3882

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is that the toner is scraped without causing abnormal noise or chipping of the edge portion. To provide a method capable of advantageously producing a urethane blade member with improved workability with good workability, and to prevent the toner from slipping through sliding contact with the photosensitive member with a sufficient pressing force. Another object of the present invention is to provide a urethane blade member that can advantageously prevent wear and chipping of the sliding contact portion without causing abnormal noise.

  And, as a result of the present inventor's earnest examination about the urethane blade member used as a cleaning blade, after applying the curing catalyst to the molding cavity surface of the molding die prior to the casting molding operation, the normal casting When the molding operation is performed, the generation of urethane bonds in the vicinity of the surface in contact with the curing catalyst is accelerated during curing, and unreacted isocyanate groups are effectively reduced. As a result, urea that is harder than urethane bonds is formed. The formation of the bond was suppressed, and it was found that the part in contact with the curing catalyst can be made lower in hardness than the main body part not in contact with the curing catalyst, and the present invention has been completed.

  That is, according to the present invention, a urethane blade member for an electrophotographic image forming apparatus, which is brought into sliding contact with the outer peripheral surface of a photoconductor and removes toner remaining on the outer peripheral surface of the photoconductor, is obtained using a polyurethane rubber material. After the polyurethane rubber raw material curing catalyst is applied or sprayed to the inner surface of the molding die, which provides at least the edge of the urethane blade member that is in sliding contact with the outer peripheral surface of the photoreceptor, The polyurethane rubber raw material is injected into the molding cavity of the molding die and cured to accelerate the curing reaction of the polyurethane rubber raw material in contact with the curing catalyst, and at the site in contact with the curing catalyst. Urethane blade portion for an electrophotographic image forming apparatus, wherein the hardness is lower than the hardness of the main body portion not in contact with the curing catalyst The method of manufacturing, it is an gist thereof.

  According to one of the preferred embodiments of the method for producing a urethane blade member for an electrophotographic image forming apparatus according to the present invention, the curing catalyst is mixed with a mold release agent to form a molding cavity surface of the molding die. Applied or sprayed.

  The present invention also provides a urethane blade member for an electrophotographic image forming apparatus that is slidably contacted with an outer peripheral surface of a photoconductor and removes toner remaining on the outer peripheral surface of the photoconductor. The edge portion that is in sliding contact with the outer peripheral surface is formed by a casting operation using the same polyurethane rubber raw material as the main body portion, and the hardness is lower than the main body portion by suppressing the generation of urea bonds, The gist of the urethane blade member for an electrophotographic image forming apparatus, characterized in that a low hardness portion is formed.

  Thus, in the method for producing a urethane blade member for an electrophotographic image forming apparatus according to the present invention, prior to injecting the polyurethane rubber material into the molding cavity of the molding die, at least the photosensitive member of the molding die. The polyurethane rubber raw material curing catalyst is applied or sprayed to the inner surface that gives the edge of the urethane blade member that is in sliding contact with the outer peripheral surface of the polyurethane rubber. This accelerates the curing reaction of the polyurethane rubber raw material in contact with the curing catalyst. Thus, the hardness of the portion in contact with the curing catalyst, that is, the hardness of at least the edge portion is lower than the hardness of the main body portion not in contact with the curing catalyst.

  More specifically, since unreacted isocyanate groups generally remain in the polyurethane rubber immediately after crosslinking that forms the blade, curing is usually performed after crosslinking. During this curing, the unreacted isocyanate group in the polyurethane rubber reacts with moisture in the air to form a urea bond that is harder than the urethane bond, and the hardness of the polyurethane rubber that gives the blade is the desired hardness. It can be raised to. Under such circumstances, in the present invention, as described above, the curing reaction of the polyurethane rubber material in contact with the curing catalyst is promoted. The unreacted isocyanate group can be effectively reduced as compared with the portion not in contact with. Therefore, at the site in contact with the curing catalyst, generation of a urea bond having a high binding force is suppressed during curing, and an increase in hardness due to the urea bond is suppressed. As a result, the bond form changes between the main body part (matrix part) that is not in contact with the curing catalyst and the surface in contact with the curing catalyst and the vicinity thereof, that is, the degree of formation of urea bonds is different, and the formation of urea bonds is different. The hardness of the suppressed part (part in contact with the curing catalyst) is lowered.

  For this reason, according to the method for producing a urethane blade member for an electrophotographic image forming apparatus according to the present invention, without using a plurality of polyurethane rubber materials, by a single cast molding operation using the same polyurethane rubber material, A high-hardness main body part and a low-hardness low-hardness part can be formed simultaneously. Therefore, according to the method of the present invention, as in the prior art, it is necessary to form the low hardness layer (edge layer) and the high hardness layer (base layer) one by one using different polyurethane rubber raw materials in order. As a result, workability is greatly improved.

  Further, according to the method of the present invention, the low hardness portion as described above is formed only on the surface of the blade in contact with the curing catalyst applied or sprayed on the inner surface of the molding die, and the hardness of the main body portion inside the blade is A moderately high hardness will be maintained. In this way, the hardness of the entire blade can be kept high while the hardness of only the surface can be reduced, so that the blade can be brought into sliding contact with the outer peripheral surface of the photoreceptor with sufficient pressing force to improve the toner scraping property. On the other hand, excessive pressing force can be advantageously prevented from being applied to the outer peripheral surface of the photoconductor, which can prevent abnormal noise generation, edge wear, chipping, etc. An excellent urethane blade member can be manufactured.

  Therefore, according to the method for producing a urethane blade member for an electrophotographic image forming apparatus according to the present invention, a urethane blade member having improved toner scraping performance without generating abnormal noise or chipping of an edge portion. Thus, it can be advantageously produced with good workability.

  Further, in the urethane blade member for an electrophotographic image forming apparatus according to the present invention, the hardness is higher than that of the main body portion by suppressing the formation of urea bonds at least at the edge portion that is in sliding contact with the outer peripheral surface of the photoreceptor. Since the low-hardness portion having a reduced thickness is formed, it is advantageously prevented from being brought into sliding contact with the photosensitive member with an excessive pressing force. Therefore, the urethane blade member for an electrophotographic image forming apparatus according to the present invention is slidably brought into contact with the photosensitive member with an adequately sufficient pressing force, and can prevent the toner from slipping through. It is also possible to advantageously prevent the contact portion from being worn or chipped.

  Furthermore, the urethane blade member for an electrophotographic image forming apparatus according to the present invention is formed by a casting operation using the same polyurethane rubber raw material as that of the main body. Unlike the case of forming the low-hardness part, no interface is formed between the main body part and the low-hardness part. Therefore, peeling occurs at the interface and durability is reduced. Nor.

  Hereinafter, in order to clarify the present invention more specifically, the configuration of a urethane blade member for an electrophotographic image forming apparatus according to the present invention and a manufacturing method thereof will be described in detail with reference to the drawings. To do.

  First, FIG. 1 schematically shows a cleaning blade in an electrophotographic copying machine, which is an embodiment of a urethane blade member for an electrophotographic image forming apparatus manufactured according to the method of the present invention, in a sectional form. . As is apparent from FIG. 1, the cleaning blade 10 of this embodiment is brought into sliding contact with the outer peripheral surface of the photoreceptor in the electrophotographic copying machine as in the conventional product, and the toner remaining there And a holder 14 as a holding member for holding the blade 12.

  More specifically, the blade 12 constituting the cleaning blade 10 is made of a polyurethane rubber material, and as a whole, has a longitudinal strip shape with a predetermined thickness and a relatively narrow width. And the edge part 20 (lower left edge part in which the holder 14 does not protrude in FIG. 1) of one end side in the width direction (left and right direction in FIG. 1) of the blade 12 is as shown in FIG. In addition, a sliding contact portion 21 that is in sliding contact with the outer peripheral surface 18 of the photosensitive member 16 is provided.

  On the other hand, the holder 14 has a structure formed by bending a substantially flat rectangular metal plate having a predetermined thickness and a predetermined width into an L shape. And the front-end | tip part 15 of the L-shaped long part is integrally formed in the state inserted in the inside of the braid | blade 12 from the end surface on the opposite side to the sliding contact part 21 side in the width direction of the braid | blade 12. As a result, the blade 12 can be held. Further, screw holes (not shown) through which a predetermined screw is inserted are provided at both ends of the holder 14 in the length direction (the direction perpendicular to the paper surface in FIG. 1). However, the holder 14 is positioned at a position where the edge portion 20 of the blade 12 is brought into sliding contact with the outer peripheral surface 18 of the photoreceptor 16 in the electrophotographic copying machine by being screwed to a predetermined portion of the cleaning device in the electrophotographic copying machine. Attached to the cleaning device, the toner remaining on the outer peripheral surface 18 of the photosensitive member 16 after transfer can be scraped off at the edge portion 20 (sliding contact portion 21) of the blade 12. .

  Thus, in the cleaning blade 10 of this embodiment having such a structure, in particular, the blade 12 is formed by a casting operation using the same polyurethane rubber material. A low hardness portion 24 (one point in FIG. 1) having a hardness lower than that of the main body portion (matrix portion) 22 on the surface or surface layer portion on one end side in the thickness direction (vertical direction in FIG. 1) including the edge portion 20. The part below the chain line is formed. That is, in the cleaning blade 10 of the present embodiment, the hardness is made lower than that of the main body 22 even though the cleaning blade 10 is formed by a cast molding operation using the same polyurethane rubber raw material as that of the main body 22. The low hardness portion 24 is formed on the blade surface including the edge portion 20 of the blade 12. Further, since the low hardness portion 24 is formed by the method described later, the hardness gradually changes from the blade surface toward the inside, and there is a clear boundary between the low hardness portion 24 and the main body portion 22. It also has the feature of not.

  As described above, in the cleaning blade 10 according to the present embodiment, the low hardness portion 24 whose hardness is lower than that of the main body portion 22 is in contact with the outer peripheral surface 18 of the photosensitive member 16 and the edge portion of the blade 12. 20 is formed with a relatively thin thickness, and as shown in an enlarged view in FIG. 3, it rotates in a predetermined direction (here, clockwise, as indicated by a in the figure). When installed on the outer peripheral surface 18 of the photoconductor 16 at a predetermined angle, the edge portion 20 is slidably contacted with the outer peripheral surface 18 of the photoconductor 16 in a state where the edge portion 20 is wound on the front side in the rotation direction of the photoconductor 16. The At this time, first, the main body portion 22 having high hardness contacts the outer peripheral surface 18 of the photosensitive member 16 with a small contact width, and most of the toner remaining on the outer peripheral surface 18 of the photosensitive member 16 is scraped by the main body portion 22. Taken. Thereafter, the low hardness portion 24 comes into contact with a larger contact width than the main body portion 22, and the toner that has passed through the main body portion 22 is surely scraped off by the low hardness portion 24. As described above, in the cleaning blade 10 according to the present embodiment, the outer peripheral surface 18 of the photosensitive member 16 is scraped by the scraping action by the main body portion 22 having high hardness and the scraping action by the low hardness portion 24 having low hardness. The slipping of the remaining toner can be effectively prevented.

  Further, in the cleaning blade 10 according to the present embodiment, since the hardness of the edge portion 20 that is in contact with a large contact width at the time of sliding contact with the photoreceptor 16 is lowered, an excessive pressing force is applied to the photoreceptor 16. Such an application to the outer peripheral surface 18 can be advantageously prevented. For this reason, in the cleaning blade 10 according to the present embodiment, abnormal noise is induced by sliding contact with the photosensitive member 16, and wear or chipping in the sliding contact portion 21 is advantageously prevented. Therefore, it has excellent durability. In addition, since no interface is formed between the main body portion 22 and the low hardness portion 24, peeling does not occur at the interface.

  Here, the low hardness portion 24 only needs to have a hardness lower than the hardness of the main body portion 22. Preferably, the MD-1 hardness is preferably higher than the hardness of the main body portion 22. It is desirable that the angle is lowered by about 3 ° to 9 °, more preferably about 3 ° to 6 °. This is because if the difference in hardness between the low hardness portion 24 and the main body portion 22 is too small, the intended effect cannot be obtained sufficiently, and abnormal noise may be generated or the sliding contact portion 21 may be worn or chipped. This is because, on the contrary, if the difference in hardness is too large, the scraping property of the toner may be lowered.

  The surface hardness (MD-1 hardness) of the low hardness portion 24 is preferably about 65 ° to 73 °, more preferably about 67 ° to 70 °, and is set to such a hardness. This advantageously prevents an excessive pressing force on the photosensitive member 16.

  Further, as described above, the low hardness portion 24 gradually increases in hardness as it goes from the surface toward the inside, so that unlike a conventional two-layer blade composed of a low hardness layer and a high hardness layer, There is no boundary between the main body portion 22 and the low hardness portion 24 that clearly separates the main body portion 22 and the low hardness portion 24. For this reason, it is difficult to accurately measure the thickness of the low hardness portion 24 as in the prior art. Preferably, the MD-1 hardness is preferably 3 ° or more lower than the MD-1 hardness of the main body portion 22. It is desirable that the thickness of the low hardness portion 24 is about 10 μm to 100 μm, more preferably about 10 μm to 60 μm. This is because if the low-hardness portion 24 is too thin, the pressing force against the photosensitive member 16 becomes excessive, and the sliding contact portion 21 (particularly, the edge portion 20) is worn or chipped, resulting in a decrease in durability. This is because abnormal noise may occur. On the contrary, if the thickness is too thick, the pressing force to the photosensitive member is reduced, the scraping property of the toner is deteriorated, and the residual toner passes through the blade 12 to cause an image defect. This is because there is a risk of being harassed.

  By the way, when manufacturing the cleaning blade 10 having such a structure in accordance with the method of the present invention, first, as shown in FIG. 4, at least the molding die 26 for molding the blade 12 of the photosensitive member 16 is formed. A curing catalyst 34 of polyurethane rubber material is applied or sprayed on the inner surface forming the edge portion 20 that is in sliding contact with the outer peripheral surface 18.

  More specifically, the molding die 26 has an upper die 28 and a lower die 30, and is intended when the upper die 28 and the lower die 30 are closed as shown in FIG. 5. A molding cavity 38 for providing the blade 12 of the cleaning blade 10 is formed so as to have two sizes of the blade 12 so that two cleaning blades 10 can be obtained. Further, on both sides of the molding cavity 38 facing each other in the width direction (left and right direction in FIG. 5), holder accommodating portions 40 and 40 into which the holder 14 of the cleaning blade 10 is inserted and arranged are respectively in the longitudinal direction (in FIG. 5). , In a direction perpendicular to the paper surface).

  In the present invention, as shown in FIG. 4, among the inner surfaces of such a molding die 26, at least an edge portion 20 (showing the cleaning blade 10 by a one-dot chain line in FIG. 4) is provided. The polyurethane rubber raw material curing catalyst 34 is applied or sprayed onto the 30 molding cavity surfaces 32. Here, the curing catalyst 34 is sprayed over the entire surface of the molding cavity surface 32 of the lower mold 30 forming the edge portion 20 by using a spray gun 36 having a known structure.

  Here, as the curing catalyst 34 for the polyurethane rubber raw material, any material that does not react with the polyurethane rubber raw material itself, increases the curing speed of the polyurethane rubber raw material, and promotes the formation of urethane bonds can be conventionally used. A well-known thing can be employ | adopted, For example, organometallic compounds, such as amine type compounds, such as a tertiary amine, and an organic tin compound, etc. can be mentioned.

  Specifically, the tertiary amine includes, for example, a trialkylamine such as triethylamine; a tetraalkyldiamine such as N, N, N ′, N′-tetramethyl-1,3-butanediamine; and dimethylethanolamine. Ethoxylated amines; ethoxylated diamines; ester amines such as bis (diethylethanolamine) adipate; triethylenediamine; cyclohexylamine derivatives such as N, N-dimethylcyclohexylamine; N-methylmonophorin; N- ( Morpholine derivatives such as 2-hydroxypropyl) -dimethylmorpholine; piperazine derivatives such as N, N′-diethyl-2-methylpiperazine and N, N′-bis- (2-hydroxypropyl) -2-methylpiperazine Can do. On the other hand, examples of the organic tin compound include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di (2-ethylhexoate), stannous 2-ethylcaproate and stannous oleate. Can be mentioned. Among these, in particular, triethylenediamine can be suitably employed because it contributes greatly to the increase in the curing rate of the polyurethane rubber raw material.

  The polyurethane raw material curing catalyst 34 as described above is appropriately dissolved in an organic solvent such as methyl ethyl ketone, toluene, acetone, tetrahydrofuran, hexane or the like so that it can be easily applied or sprayed if it is solid at room temperature. On the other hand, if it is liquid at room temperature, it is applied or sprayed to the molding cavity surface 32 of the lower mold 30 as it is or after being appropriately diluted with a solvent as described above. More preferably, the mold cavity surface 32 is mixed with a mold release agent that has been conventionally used for molding dies when manufacturing a urethane blade, such as a silicone and / or fluorine mold release agent. It is desirable that the mold release agent and the curing catalyst 34 can be applied or sprayed to the molding cavity surface 32 at the same time by one application or spraying operation. The workability is further improved, and the use of excess solvent can be suppressed.

Further, the coating amount or the spraying amount of the polyurethane raw material curing catalyst 34 can be appropriately set in accordance with the curing catalyst used in consideration of its catalytic ability and the like, but preferably 0.1 μg / mm ^{2 to} 10 μg. / mm ^2, it is desirable that more preferably a ^{0.2μg / mm 2 ~5μg / mm 2} . This is because if the coating amount or spraying amount of the curing catalyst 34 is too smaller than the above range, the reaction promoting effect by the curing catalyst 34 cannot be sufficiently obtained, and if it exceeds the above range, This is because the curing catalyst 34 becomes excessive and the low hardness portion 24 may be formed thicker than necessary.

  Further, when the curing catalyst 34 is mixed with the release agent, the blending amount of the curing catalyst 34 with respect to the release agent is appropriately set according to the curing catalyst 34 and the release agent to be used, and is particularly limited. However, it is preferably 0.01% by weight to 0.1% by weight, more preferably 0.05% by weight, so that both the release action by the release agent and the catalytic action by the curing catalyst 34 can be advantageously obtained. It is desirable to use in the range of 0.1% by weight. The reason for this is that when the amount of the curing catalyst 34 is too small, the catalytic effect of the curing catalyst 34 cannot be obtained unless a large amount of release agent is applied or sprayed onto the molding cavity surface 32. This is because when the amount of the curing catalyst 34 is too large, the curing catalyst 34 becomes excessive unless the amount of the release agent applied or sprayed is reduced.

  Thus, after applying or spraying the curing catalyst 34 to a predetermined portion of the inner surface of the molding die 26 as described above, the upper die 28 and the lower die 30 of the molding die 26 are shown in FIG. At least one of them is relatively close to the other in the vertical direction, and the mold is closed. As a result, a molding cavity 38 and two holder accommodating portions 40 and 40 are formed between the upper mold 28 and the lower mold 30 of the molding die 26. And in each holder accommodating part 40, as FIG. 6 shows, the two holders 14 and 14 which consist of a metal flat plate shape | molded by press work etc. to the L-shaped cross section are made into the L-shaped longitudinal part. Are accommodated in the holder accommodating portions 40 and set so that the distal end portions 15 thereof are positioned in the molding cavities 38.

  Next, as shown in FIG. 7, with the two holders 14 and 14 inserted into the molding cavity 38, the polyurethane rubber raw material 42 is injected into the molding cavity 38 of the molding die 26 through an injection port (not shown). , React to cure. At this time, as the heating temperature and heating time of the polyurethane rubber raw material 42, the same temperature and time as in the conventional case can be adopted. The heating temperature is generally about 110 ° C. to 150 ° C., and the heating time is generally 3 ° C. Minutes to 20 minutes.

  Here, the polyurethane rubber raw material 42 used in the present invention is not particularly limited, and a known liquid composition conventionally used in the production of urethane blades is appropriately selected and used. Such a polyurethane rubber raw material 42 is generally composed of a main agent (polyisocyanate-containing component) and a curing agent (polyol component).

  Here, as the main agent, a conventionally known polyisocyanate-containing component can be employed. For example, 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, Isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate (NBDI), tolylene diisocyanate (TDI), phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1 , 5-naphthalene diisocyanate, xylylene diisocyanate (XDI), carbodiimide-modified MDI, urethane-modified MDI and the like, and these polyisocyanates A prepolymer composed of at least one of the above-mentioned components and a polyester polyol, and isocyanurate bodies such as hexamethylene diisocyanate and isophorone diisocyanate, biuret bodies, modified adduct bodies, and the like. One of them is used alone, or two or more of them are used in combination. Among these, a prepolymer composed of MDI and polyester polyol is preferably employed.

  On the other hand, examples of the curing agent include ethylene glycol, propylene glycol, butanediol, hexanediol, trimethylolpropane, diethylene glycol, glycerin, polyester polyols such as polyethylene adipate and polybutylene adipate, and the like. Are used alone or in combination of two or more. Among these, a mixture of 1,4-butanediol, trimethylolpropane and polyester polyol is preferably employed.

  Further, the mixing ratio of the main agent and the curing agent, that is, the NCO index (equivalent of NCO group to 100 equivalent of OH group) is not particularly limited, and a ratio similar to that of a conventional urethane blade can be adopted. However, among these, it is desirable to set in the range of 100 to 130. By using such an NCO index, the hardness difference between the low hardness portion 24 and the main body portion 22 can be more advantageously described above. Such a suitable range can be obtained. Furthermore, the polyurethane rubber raw material 42 having a main agent and a curing agent may include a flame retardant, a filler, a colorant, a plasticizer, a stabilizer, a curing catalyst, a release agent, etc. Various known additives may be added.

  Thus, by injecting and curing such a polyurethane rubber raw material 42, as shown in FIG. 8, a polyurethane rubber block body 44 having the size of two of the blades 12 is formed in the molding cavity 38, as shown in FIG. In addition to being formed, the polyurethane rubber block body 44 and the holder 14 are firmly fixed and integrated.

  At this time, in the present invention, the curing catalyst 34 is applied to or sprayed on the molding cavity surface 32 of the lower mold 30, and the polyurethane rubber raw material 42 injected into the molding cavity 38 of the lower mold 30. The portion that is in contact with the molding cavity surface 32, that is, the portion that is in contact with the curing catalyst 34 is more effectively increased in curing speed than the main body that is not in contact with the curing catalyst 34, and the urethane bond formation reaction is accelerated. It is supposed to be done.

Then, after crosslinking for a predetermined time, the molding die 26 is opened, and the polyurethane rubber block body 44 in which the two holders 14 and 14 are integrated is removed. In the polyurethane rubber block body 44 immediately after crosslinking thus demolded, unreacted isocyanate groups (NCO groups) usually remain in the block body 44 and are not yet fully cured. Therefore, after removing the mold, the polyurethane rubber block body 44 is left to stand in a room temperature environment (temperature: around 23 ° C., humidity: around 58%) for curing. In this curing, the unreacted NCO group in the block body 44 reacts with moisture in the air, whereby the hardness of the polyurethane rubber block body 44 is increased to the target hardness. More specifically, an unreacted NCO group in the block body 44 reacts with moisture in the air to generate amine (—NH ₂ ), and this amine further reacts with an unreacted NCO group. Therefore, it is presumed that a urea bond harder than the urethane bond is formed, and the hardness of the polyurethane rubber block body is increased to a target hardness.

  At this time, in the polyurethane rubber block body 44 formed in accordance with the method of the present invention, the urethanization reaction at the portion in contact with the molding cavity surface 32 of the lower mold 30, that is, the portion in contact with the curing catalyst 34 is promoted. Therefore, more NCO groups are consumed, and the unreacted NCO groups present in the portion are effectively reduced as compared with the main body portion not in contact with the curing catalyst 34. For this reason, at the site | part which contacted the curing catalyst 34, the generation | occurrence | production of the urea bond as mentioned above is suppressed at the time of curing, and the raise of the hardness by a urea bond is suppressed. As a result, the hardness of the portion in contact with the curing catalyst 34 is made lower than that of the main body not in contact with the curing catalyst 34, so that the same hardness of the main body 22 from the same polyurethane rubber raw material 42 and the low hardness is low. The hardness part 24 is formed.

  Then, the polyurethane rubber block body 44 thus cured is cut into two at the center in the width direction so as to have a predetermined dimension, so that the blade 12 made of polyurethane rubber is attached to the holder. Two of the target cleaning blades 10 formed integrally with each other are manufactured at the same time.

  In the cleaning blade 10 manufactured in this way, as shown in FIG. 1, the surface on one end side in the thickness direction including the edge portion 20 that is slidably contacted with the outer peripheral surface 18 of the photoreceptor 16. In the surface layer portion, a low-hardness portion 24 made of the same polyurethane rubber material as that of the main body portion 22 and having a lower hardness than the main body portion 22 by suppressing the formation of urea bonds is formed thinly. It is. On the other hand, most of the cut surface 13 formed by cutting the polyurethane rubber block body 44 is the main body 22 having high hardness.

  As described above, in the present embodiment, prior to injecting the polyurethane rubber material into the molding cavity of the molding die, at least the edge portion 20 of the molding die 26 that is in sliding contact with the outer peripheral surface 18 of the photosensitive member 16. By simply applying or spraying the curing catalyst 34 of the polyurethane rubber raw material 42 to the molding cavity surface 32 that provides the same, without using a plurality of polyurethane rubber materials, by one casting molding operation using the same polyurethane rubber material, The low hardness portion 24 having a lower hardness than the main body portion 22 can be formed on the surface in contact with the curing catalyst 34. For this reason, according to this embodiment, the polyurethane blade member which has the above outstanding characteristics can be manufactured advantageously with good workability.

  Further, if the curing catalyst 34 of the polyurethane rubber raw material 42 is mixed with the release agent and applied or sprayed onto a predetermined portion of the inner surface of the molding die 26, the release agent and the curing catalyst 34 are applied once. Or it can be applied or sprayed on the molding cavity surface 32 at the same time by the spraying operation, and the workability is further improved.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the above example, as shown in FIG. 4, the curing catalyst 34 of the polyurethane rubber material is sprayed on the molding cavity surface 32 that gives the edge portion 20 using the spray gun 36. The spraying method is not particularly limited, and a conventionally known coating or spraying method may be employed. For example, the curing catalyst 34 may be applied using a brush, a roller, or the like. Is possible.

  The range in which the polyurethane raw material curing catalyst 34 is applied or sprayed onto the inner surface of the molding die 26 is not limited to the above example. Specifically, in the above example, the curing catalyst 34 of the polyurethane rubber raw material was sprayed on the entire surface of the molding cavity surface 32 of the lower mold 30 that forms the edge portion 20, but at least the portion that gives the edge portion 20, That is, if the curing catalyst 34 is applied or sprayed in a straight line so as to extend in the longitudinal direction at the center portion in the width direction (left and right direction in FIG. 4) of the molding cavity surface 32 of the lower mold 30, the edge portion The low hardness part 24 is formed in 20 and its vicinity, and the desired effect will be acquired. For this reason, it is only necessary to spray the curing catalyst 34 to at least a portion (a part of the molding cavity surface 32) that gives the edge portion 20, and the curing catalyst does not necessarily extend over the entire molding cavity surface 32 of the lower mold 30 as in the above example. 34 need not be sprayed. Conversely, the curing catalyst 34 is sprayed not only on the molding cavity surface 32 of the lower mold 30 that forms the edge portion 20 (sliding contact portion 21) but also on the molding cavity surface 29 of the upper die 28 that does not form the edge portion 20. However, there is nothing wrong.

  In addition, in the above embodiment, the blade 12 and the holder 14 are integrated by performing the cast molding operation with the tip 15 of the holder 14 inserted into the molding cavity 38. It is of course possible to attach the holder 14 to a predetermined part of the blade 12 and to integrate the blade 12 and the holder 14 after molding.

  Moreover, in the said embodiment, using the shaping | molding die 26 which has the molding cavity 38 which has the magnitude | size for two of the braid | blade 12, and the two holder accommodating parts 40 and 40 in which the holder 14 is accommodated one by one, Two target cleaning blades 10 are manufactured at the same time in one molding operation, but only a molding cavity having a shape corresponding to one blade 12 and one holder housing portion are formed. Of course, it is possible to manufacture only one target cleaning blade 10 by a single molding operation using a mold.

  Furthermore, it goes without saying that the shape of the blade 12 and the holder 14 and the overall shape of the cleaning blade 10 are not limited to those shown in the above embodiment.

  In the above-described embodiment, specific examples of applying the present invention to the cleaning blade and the manufacturing method thereof in the electrophotographic copying machine have been shown. However, the present invention is not limited to printers, facsimiles, and multifunction devices thereof. In the electrophotographic image forming apparatus such as the above, it can be advantageously applied to any of the urethane blade member for an electrophotographic image forming apparatus mounted as a cleaning blade and the manufacturing method thereof.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the present invention.

  Several examples of the present invention will be shown below to clarify the present invention more specifically. However, the present invention is not limited by the description of such examples.

  First, as a mold, a mold having a structure shown in FIGS. 4 to 8 having a molding cavity having a size of two blades and a holder accommodating portion capable of accommodating two holders was prepared. In addition, N-2-hydroxypropyltrimethylammonium 2-ethylhexanoate (DABCO TMR, manufactured by Sankyo Air Products), which is an amine catalyst, was prepared as a curing catalyst for the polyurethane rubber raw material sprayed on the molding cavity surface. Was mixed with a silicone-based mold release agent so as to have a mixing ratio shown in Table 1 below.

  Then, after the mold is heated to 130 ° C. in advance, the silicone mold release agent in which the amine catalyst is mixed at a predetermined ratio is sprayed on the inner surface of the lower mold that gives the edge part (sliding contact part). While spraying using a gun under the conditions of supply amount: 0.15 g / 10 seconds and speed (= gun movement distance / hour): 350 mm / 2.1 seconds, an amine-based catalyst is blended on the inner surface of the upper mold. The above silicone mold release agent was sprayed under the same conditions. For comparison, the silicone mold release agent not containing an amine catalyst is added to the inner surfaces of the upper and lower molds according to Comparative Examples 1 to 3 shown in Table 1 below. Sprayed under the same conditions.

  Then, the holder which consists of a galvanized steel plate made into the L shape was set to each of two holder accommodating parts of the shaping die sprayed with the mold release agent by bending a long flat plate.

  On the other hand, a two-component polyurethane raw material having a material viscosity of 0.5 to 1.0 Pa · s was prepared as a polyurethane rubber raw material. More specifically, a prepolymer obtained by reacting MDI and polyethylene adipate is prepared as a main agent, while a mixture of 1,4-butanediol, trimethylolpropane, and polybutylene adipate is prepared as a curing agent. did. In addition, N-2-hydroxypropyltrimethylammonium 2-ethylhexanoate (DABCO TMR, Sankyo Air Products) which is an amine catalyst is used so that the curing reaction rate after mixing with the curing agent is 2 minutes / 100 Pa · s. Were mixed so as to be 80 ppm. The main agent and the curing agent are each preliminarily heated to 80 ° C. and defoamed at 100 Pa for 1 hour or longer, respectively, and then the main agent and the curing agent have NCO indexes shown in Table 1 below. To prepare a polyurethane raw material.

  Then, the polyurethane raw material immediately after mixing was poured into a molding cavity of a molding die on which two holders were set, and reacted at 130 ° C. for 10 minutes to cure the polyurethane rubber raw material in the molding cavity. Thereafter, the polyurethane rubber block body cured in the molding cavity was removed from the mold and allowed to stand in a room temperature environment for 48 hours for curing. Then, the polyurethane rubber block body after curing is cut into two, and thereby a cleaning blade having blades 12 of length: 330 mm, width: about 8 mm, thickness: about 2 mm (Examples 1 to 4 and comparison) Examples 1 to 3) were obtained.

  And about the cleaning blade (Examples 1-4 and Comparative Examples 1-3) manufactured in this way, the following each measurement was performed and the obtained result was combined with following Table 1, and was shown. In addition, the measurement mentioned later was implemented in room temperature (23 degreeC) environment unless it mentions specially.

-MD-1 hardness-
The MD-1 hardness of the sliding contact portion (in FIG. 1, near the edge portion on the lower surface of the blade) and the main body portion (in FIG. 1, the upper surface of the blade) is measured with a micro rubber hardness meter (microdurometer MD-1 UPX533M-A, polymer Using an instrument company), five points were measured, and the average value was obtained.

-Pressing force against photoconductor-
The obtained cleaning blade is brought into contact with the outer peripheral surface of a cylindrical virtual photosensitive member (outer diameter: 30 mm, outer peripheral width: 350 mm) in a state inclined by 24 ° from the tangent, and then perpendicular to the tangent. The pressing force received by the virtual photoconductor in this state was measured with a load cell.

-Image evaluation and chipping resistance-
The obtained cleaning blade was incorporated into a commercially available laser printer (LASER-SHOT LBP-2710, toner cartridge: EP-86CRG, manufactured by Canon) at 10 ° C. (low temperature), 23 ° C. (room temperature), and 32 ° C. (high temperature). Under each temperature environment, 20,000 images were printed. The image after printing 20,000 sheets was visually observed, and the case where no streak or the like due to toner slipping occurred was evaluated as ◯, and the case where the streak or the like was generated was evaluated as ×. Also, the edge of the cleaning blade (sliding contact portion) after printing 20,000 sheets was observed with a scanning electron microscope at an enlargement ratio of 50 times, and there was no chipping at all, or 10 μm A sample having the following chip was evaluated as x, and a sample having a chip exceeding 10 μm was evaluated as x.

-Evaluation of abnormal noise-
The obtained cleaning blade was incorporated into a commercially available laser printer (LASER-SHOT LBP-2710, manufactured by Canon Inc.) for printing. During printing, a case where no sound was heard from the laser printer due to rubbing between the cleaning blade and the photosensitive member was evaluated as ◯, and a case where it was heard was evaluated as ×.

  As is clear from the results in Table 1, in each of the cleaning blades according to Examples 1 to 4, the MD− of the sliding contact portion in contact with the curing catalyst sprayed on the molding cavity surface of the mold was used. 1 hardness is lower by about 3 ° to 7 ° than the MD-1 hardness of the main body portion, and it can be seen that a low hardness portion lower in hardness than the main body portion is formed in the sliding contact portion. Further, in the cleaning blades according to Examples 1 to 4 in which such a low hardness portion was formed, no abnormal noise was generated, and the cleaning blades were in any environment of 10 ° C, 23 ° C, and 32 ° C. However, the chipping resistance and image evaluation are good, and it is recognized that the toner scraping property is imparted well in a wide temperature range from a low temperature (about 10 ° C.) to a high temperature (about 32 ° C.). It is done.

  On the other hand, it can be seen that the cleaning blades according to Comparative Examples 1 to 3 in which the low hardness portion is not formed have poor chipping resistance and image evaluation. Further, in Comparative Examples 1 and 2 in which the MD-1 hardness of the sliding contact portion is higher than the hardness of the sliding contact portions of Examples 1 to 4, abnormal noise is generated.

-Micro displacement hardness measurement-
Moreover, the micro displacement hardness measurement of the cleaning blade (Examples 1-4 and the comparative example 2) obtained above was performed, and the obtained result was plotted on the graph of FIG. Specifically, using a micro displacement hardness meter (Fischer scope H100C, manufactured by Fischer Co., Ltd.) to which a Vickers needle is attached, on the side (sliding part side) in contact with the molding cavity surface of the lower mold in 10 seconds. A load was applied from 0 mN to 100 mN. A curve indicating the insertion depth of the needle with respect to the load at this time is shown by a solid line in FIG.

  As is clear from FIG. 9, the cleaning blades of Examples 1 to 4 are at the time of rising (load: around 0 to 20 mN) as compared with the cleaning blade according to Comparative Example 2 in which the low hardness portion is not formed. It is recognized that the inclination is large and the surface is softer than in Comparative Example 2. On the other hand, at a load of 30 to 100 mN, all of the cleaning blades have substantially the same inclination, and the inside (main body portion) is considered to have the same degree of hardness. Moreover, it can be seen from Examples 1 to 4 that the slope at the time of rising gradually increases, and that the thickness of the low-hardness portion increases as the coating amount of the curing catalyst increases.

It is a section explanatory view showing an example of a urethane blade member for electrophotographic image forming devices according to the present invention. FIG. 3 is an explanatory cross-sectional view showing a state in which a urethane blade member for an electrophotographic image forming apparatus according to the present invention is in sliding contact with a photoreceptor. FIG. 3 is a partially enlarged explanatory view in FIG. 2. 1 is a cross-sectional explanatory view showing one embodiment of a process for producing a urethane blade member for an electrophotographic image forming apparatus in accordance with the method of the present invention, showing a state in which a curing catalyst of a polyurethane rubber raw material is sprayed on the inner surface of a molding die. ing. FIG. 5 is an explanatory cross-sectional view showing a closed state of the molding die shown in FIG. 4. FIG. 4 is a cross-sectional explanatory view showing another embodiment of a process for producing a urethane blade member for an electrophotographic image forming apparatus according to the method of the present invention, in which a holder is set in a molding die sprayed with a curing catalyst of a polyurethane rubber raw material Indicates the state. FIG. 4 is a cross-sectional explanatory view showing still another embodiment of a process for producing a urethane blade member for an electrophotographic image forming apparatus according to the method of the present invention, and injecting a polyurethane rubber raw material for giving a blade into a molding cavity of a molding die Shows the state. FIG. 4 is a cross-sectional explanatory view showing another embodiment of a process for producing a urethane blade member for an electrophotographic image forming apparatus according to the method of the present invention, and curing a polyurethane rubber raw material injected into a molding cavity of a molding die. Shows a state in which a block body of polyurethane rubber is formed. It is a graph which shows the result of the micro displacement hardness measurement in an Example, Comprising: The insertion depth of the needle with respect to a load is plotted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cleaning blade 12 Blade 14 Holder 15 Front-end | tip part 16 Photoconductor 18 Outer peripheral surface 20 Edge part 21 Sliding contact part 22 Main body part 24 Low hardness part 26 Molding die 28 Upper mold | type 30 Lower mold | type 32 Lower mold | mold cavity surface 34 Curing catalyst 36 Spray gun 38 Molding cavity 40 Holder housing part 42 Raw material for polyurethane rubber 44 Block body of polyurethane rubber

Claims (3)

A urethane blade member for an electrophotographic image forming apparatus that is brought into sliding contact with the outer peripheral surface of the photosensitive member and removes toner remaining on the outer peripheral surface of the photosensitive member is manufactured by a cast molding operation using a polyurethane rubber raw material. On the occasion
After applying or spraying a curing catalyst of the polyurethane rubber raw material to at least an inner surface of the molding die that provides an edge portion of the urethane blade member that is in sliding contact with the outer peripheral surface of the photoreceptor, the polyurethane rubber raw material is By injecting into the molding cavity of the molding die and curing, the curing reaction of the polyurethane rubber material in contact with the curing catalyst is promoted, and the hardness of the portion in contact with the curing catalyst is brought into contact with the curing catalyst. A method for producing a urethane blade member for an electrophotographic image forming apparatus, wherein the urethane blade member is formed to have a lower hardness than a non-main body.   The method for producing a urethane blade member for an electrophotographic image forming apparatus according to claim 1, wherein the curing catalyst is mixed with a release agent and applied or sprayed onto a molding cavity surface of the molding die. A urethane blade member for an electrophotographic image forming apparatus that is slidably contacted with an outer peripheral surface of a photoconductor to remove toner remaining on the outer peripheral surface of the photoconductor,
At least at the edge portion that is in sliding contact with the outer peripheral surface of the photoconductor, it is formed by a cast molding operation using the same polyurethane rubber raw material as the main body portion, and has a hardness higher than that of the main body portion by suppressing the formation of urea bonds. A urethane blade member for an electrophotographic image forming apparatus, wherein a low-hardness portion having a reduced hardness is formed.

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