JP2007052062A - Cleaning blade and manufacturing method therefor, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning blade designed such that the hardness characteristics of its surface and a part near the surface are controlled and friction is lessened, to provide a manufacturing method for the cleaning blade, and to provide a photographic apparatus equipped with the cleaning blade. <P>SOLUTION: The cleaning blade is characterized in which: (a) a hard layer is formed as the outermost layer of a contact part; (b) the dynamic hardness of the surface of the hard layer is 0.21N/μm<SP>2</SP>or more but 1.50N/μm<SP>2</SP>or less; (c) a change in the dynamic hardness of the hard layer in the range of 0.1 mm from the surface is 0.12mN/μm<SP>2</SP>or more but -0.04 mN/μm<SP>2</SP>or less; and (d) the dynamic hardness of the cleaning blade, except the hard layer, is 0.05 mN/μm<SP>2</SP>or more but 0.16 mN/μm<SP>2</SP>or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning blade for removing toner remaining on a toner carrier such as a photosensitive drum, a transfer belt, and an intermediate transfer member used in an electrophotographic apparatus, a method for manufacturing the same, and electrophotography using the cleaning blade. It relates to the device.

  The electrophotographic apparatus is provided with various cleaning blades for removing toner remaining on a toner carrier such as a photosensitive drum, a transfer belt, and an intermediate transfer member. These cleaning blades are manufactured from a thermoplastic or thermosetting polyurethane resin or the like, and are mainly manufactured from a thermosetting polyurethane resin from the viewpoint of plastic deformation and wear resistance.

  However, when a conventional cleaning blade made of a polyurethane resin is used, the friction coefficient between the polyurethane resin and the toner carrier is large, so the cleaning blade may be swollen, and it is necessary to increase the driving torque of the toner carrier. There was a case. In addition, the tip of the cleaning blade is wound around a photosensitive drum or the like, and is stretched and cut to break the tip of the cleaning blade. These problems are particularly remarkable when the hardness of the cleaning blade is low, and as a result, the durability of the cleaning blade may be insufficient.

  In order to solve the above problems, attempts have been made to make the contact portion made of polyurethane resin high in hardness and low in friction.

  For example, in Patent Document 1, the contact portion is composed of two layers of a contact portion and a support portion, the contact portion has a JIS-A hardness of 70 ° to 85 °, and the support portion has a hardness of 65 ° to 70 °. A cleaning blade having a configuration in which the contact portion has high hardness is disclosed. Further, Patent Document 2 discloses a cleaning blade whose surface hardness is increased by coating a vinylidene fluoride resin containing a solid lubricant on the surface.

However, these cleaning blades have a large difference in hardness between the support portion and the surface (contact portion). For this reason, when an endurance test is actually performed with an electrophotographic apparatus, excessive stress is applied to the contact portion with the toner carrier, and a crack is generated from the interface portion between the support portion and the contact portion of the cleaning blade, and finally, Could be damaged.
JP 2002-214989 A (P5, FIG. 1) JP 2000-147972 A (P6, FIG. 1)

  In order to solve the above-described problems, the present invention provides a low-friction cleaning blade in which the hardness characteristics of the surface and the vicinity of the surface are controlled, a manufacturing method thereof, and an electrophotographic apparatus equipped with the cleaning blade. Objective.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

1. A cleaning blade made of polyurethane resin that has a contact portion that contacts the toner carrier in part and that cleans and removes toner remaining on the toner carrier,
(A) having a hardened layer having a thickness of 0.1 mm or more as the outermost surface layer of the contact portion;
(B) Dynamic hardness of the hardened layer surface is 0.21 mN / μm ² or more and 1.50 mN / μm ² or less,
(C) The amount of change in dynamic hardness from the surface to the 0.1 mm portion on the inner side in the thickness direction of the cured layer is −0.12 mN / μm ² or more and −0.04 mN / μm ² or less,
(D) A cleaning blade having a dynamic hardness of 0.05 mN / μm ² or more and 0.16 mN / μm ² or less in a portion other than the hardened layer of the cleaning blade.

  2. 2. The cleaning blade according to item 1, wherein the thickness of the hardened layer is 0.12 mm or more and 1.2 mm or less and 70% or less of the thickness of the cleaning blade.

3. The manufacturing method of the cleaning blade according to 1 or 2 above,
(1) manufacturing a cleaning blade preliminary body made of polyurethane resin;
(2) impregnating at least a part of the cleaning blade preform with an isocyanate compound solution;
(3) A process for producing a cleaning blade, comprising: a step of reacting the cleaning blade preliminary body with the isocyanate compound to provide a cured layer on the surface of the cleaning blade preliminary body to form a cleaning blade.

  4). 4. The method for producing a cleaning blade as described in 3 above, wherein the isocyanate compound solution is obtained by diluting an isocyanate compound with an organic solvent.

  5. 3. An electrophotographic apparatus comprising the cleaning blade according to 1 or 2 above, an electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transferring unit.

  In the present specification, the “cleaning blade preliminary body” refers to a cleaning blade that is not impregnated with the isocyanate compound solution before the treatment in steps (2) and (3), and is a polyurethane resin molded into a predetermined blade shape. Represents a cleaning blade made of

  The “thickness direction” represents a direction perpendicular to the surface of the cured layer. For example, in FIG. 1B, both the free length direction 11 and the width direction 12 are represented.

  The “cleaning blade made of polyurethane resin” means that a part of polyurethane resin formed from polyol, isocyanate compound and curing agent reacts with isocyanate compound to form allophanate bond, moisture in the air, etc. This represents the cleaning blade that has reacted with.

  In the present invention, the hardness in the vicinity of the surface of the cleaning blade is controlled, and further, the difference in hardness between the surface and the inside of the hardened layer is set to a predetermined condition, so that the cleaning blade is less likely to be chipped, squeezed, etc. A low-friction cleaning blade that can be improved, a manufacturing method thereof, and an electrophotographic apparatus equipped with the cleaning blade can be provided.

1. Manufacturing method of cleaning blade The cleaning blade of the present invention contains a polyurethane resin and has a hardened layer as the outermost surface layer of the contact portion. The cured layer is prepared by preparing a cleaning blade preliminary containing a polyurethane resin in advance (step (1)) and then impregnating the cleaning blade preliminary with an isocyanate compound solution (step (2)). It is produced by reacting (polyurethane resin) and an isocyanate compound to cure the surface of the cleaning blade preliminary body to provide a cured layer (step (3)).

  That is, when the cleaning blade preliminary body is manufactured, it is prepared by setting the blending ratio of the polyurethane resin raw material (polyol, isocyanate compound) and reaction conditions to predetermined conditions in advance according to desired characteristics (step (1)).

  Thereafter, the cleaning blade preliminary body is impregnated with an isocyanate compound solution so that the polyurethane resin and the isocyanate compound can react on the surface of the cleaning blade preliminary body (step (2)). At this time, at least a part of the cleaning blade preliminary body may be impregnated with the isocyanate compound solution.

  Next, the polyurethane resin, the isocyanate compound, and moisture in the air are reacted to form a hardened layer in which allophanate bonds and the like are formed on a part of the cleaning blade preliminary body (step (3)). This reaction may be performed when the cleaning blade preliminary body is impregnated with the isocyanate compound solution, or may be performed by allowing the cleaning blade preliminary body to stand under predetermined conditions after impregnation with the isocyanate compound solution. In this step, it is considered that the isocyanate compound multimerization reaction proceeds at the same time and contributes to the formation of the cured layer.

  By producing the cleaning blade of the present invention by such a method, a hardened layer having a desired hardness range can be formed on the surface of the cleaning blade. The hardness of the hardened layer and to which part of the cleaning blade the hardened layer is formed depend on the manufacturing conditions (temperature, type of raw material, raw material composition, etc.) of the cleaning blade preliminary in step (1), step ( 2) Impregnation conditions (temperature, impregnation time, isocyanate compound concentration in the isocyanate compound solution, type of raw material, etc.) of the cleaning blade preliminary body in the cleaning blade preliminary body, and standing conditions (temperature, time, humidity, It can be adjusted depending on under what kind of atmosphere.

2. Cleaning Blade FIG. 1 shows an example of the cleaning blade of the present invention. In this example, a hardened layer 15 having an inverted L-shaped cross-sectional shape is formed in the free length direction 11 and the width direction 12 of the cleaning blade. The hardened layer 15 is continuously formed in the vicinity of the contact portion 14 with the toner carrier including the end portion 16 in the longitudinal direction 10 of the cleaning blade. In the present invention, a hardened layer is formed only on a part of the cleaning blade, but the hardened layer has other parts of the cleaning blade (unprocessed part that has not reacted with the isocyanate compound in step (3)), color, surface It can be clearly identified by its properties.

  In the present invention, since the hardened layer is formed only on the contact portion 14, the rubber elasticity of the free length portion 13 is maintained. For this reason, it is suppressed that the rigidity as the whole cleaning blade becomes too high, good followability to the toner carrier can be realized, and excellent cleaning properties can be realized. In addition, good adhesion between the toner carrier and the cleaning blade is realized, and the toner carrier is prevented from being damaged by the cleaning blade.

  In the present specification, the free length portion means a portion that is not treated with an isocyanate compound and a cured layer is not formed, and is also referred to as an untreated portion.

  The cross-sectional shape of the hardened layer is not particularly limited, and examples thereof include a U shape, an L shape, a triangle, and a trapezoid.

(Cleaning blade dimensions)
In FIG. 1B, L1 represents the length in the free length direction 11 of the cured layer, L2 represents the length in the width direction 12 of the cleaning blade, and T represents the thickness of the cured layer. Here, the “thickness of the cured layer” represents the thickness in the direction perpendicular to the surface direction of the surface from the surface of the cured layer. Note that. In FIG. 1B, only the thickness T in the free length direction 11 is shown as the thickness of the cured layer, but the thickness in the width direction 12 may be used.

  L1 is preferably 0.2 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more in order to make the effect of the cured layer sufficient. Further, L1 is preferably 50% or less, more preferably 45% or less of the free length in order to realize rubber elasticity of the free length part. By setting L1 within these ranges, it is possible to suppress a steep increase in linear pressure due to the entry of the current section into the toner carrier, so that a stable linear pressure can be obtained.

  The free length means the length in the free length direction where the cleaning blade is exposed from the support member, and is generally 5 mm or more and 15 mm or less.

  L2 is preferably 0.2 mm or more, more preferably 0.5 mm or more, and still more preferably 1 mm or more in order to make the effect of the cured layer sufficient. Further, it may be less than the thickness of the cleaning blade.

  T is 0.12 mm or more, preferably 0.13 mm or more, 1.2 mm or less, and preferably 1.0 mm or less. The thickness of the hardened layer is preferably 70% or less of the thickness of the cleaning blade. The “hardened layer thickness” may be the thickness in any of the free length direction 11 and the width direction 12, but the thickness of the cleaning blade represents the thickness in the width direction 12 (L3 in FIG. 1B). ). If the thickness of the hardened layer is within such a range, even if the surface of the cleaning blade is worn, good characteristics of the surface of the cleaning blade are maintained for a long time. Furthermore, since the hardened layer has a sufficient thickness, the surface of the cleaning blade is prevented from being greatly deformed by sliding with the toner carrier, so that minute toners and spherical toners used in recent years are also included. It can be removed efficiently.

(Cleaning blade spare body hardness)
The international rubber hardness (IRHD) of the cleaning blade preliminary body based on the polyurethane resin before forming the cured layer is preferably 60 ° or more and less than 80 °. In this case, the cleaning blade obtained by impregnating the cleaning blade preliminary body with the isocyanate compound solution is flexible and rich in rubber elasticity as a whole. Further, good adhesion between the toner carrier and the cleaning blade can be realized, and the toner carrier can be prevented from being damaged by the cleaning blade.

(Polyurethane resin)
Further, the isocyanate group content (NCO%) of the polyurethane resin contained in the cleaning blade preliminary body is preferably 5% or more and 20% or less in order to realize good elastic characteristics. The isocyanate group content (NCO%) is the mass% of the isocyanate functional group (NCO, molecular weight calculated as 42) contained in 100 g of the prepolymer or semi-prepolymer that is the raw material of the polyurethane resin. Calculated by the formula;
NCO% = (mass of isocyanate functional group g / 100 g) × 100.

  As the polyurethane resin, those obtained by partially polymerizing a polyisocyanate compound and a polymer polyol, and those obtained by thermosetting low molecular weight dihydric alcohol or trihydric or higher polyhydric alcohol as a curing agent are used.

  Polyisocyanate compounds include 4,4 ′,-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (H-MDI), trimethylhexamethylene diisocyanate (TMHDI), tolylene diene Isocyanate (TDI), carbodiimide-modified MDI, polymethylene polyphenyl polyisocyanate, orthotoluidine isocyanate (TODI), naphthylene diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), paraphenylene diisocyanate (PDI), Examples include lysine diisocyanate methyl ester (LDI) and dimethyl diisocyanate. These may be used alone or in combination of two or more.

  Examples of the polymer polyol include polyester polyols such as polyethylene adipate, polybutylene adipate, polyhexylene adipate, a copolymer of ethylene diadipate and butylene adipate, polycaprolactone, polyoxytetramethylene glycol, polyoxypropylene glycol, and the like. A polyether polyol is mentioned. Of these, those having a weight average molecular weight of about 1500 to 3000 are preferred. When the weight average molecular weight is less than 1500, the resulting polyurethane resin tends to have decreased physical properties. When the weight average molecular weight is 3000 or more, the prepolymer viscosity increases, and the workability of the elastic blade molding tends to be remarkably deteriorated. is there.

  Further, as the curing agent, a low molecular weight dihydric alcohol having a molecular weight of 300 or less or a polyhydric alcohol having a valence of 3 or more is used. Examples of low molecular weight dihydric alcohols include ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), 1,4-butanediol (BD), hexanediol, 1,4-hexanediol (HD), etc. Is mentioned. Further, as trihydric or higher alcohols, for example, trifunctional aliphatic polyols such as glycerin, 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, and the above trifunctional aliphatic polyols. Examples include polyether triols in which ethylene oxide, butylene oxide, etc. are added, and polyester triols in which lactone is added to the trifunctional aliphatic polyol. These curing agents can be used alone or in admixture of two or more.

  Examples of the method for forming the cleaning blade preliminary body include a one-shot method, a prepolymer method, and a semi-one-shot method.

(Isocyanate compound solution used in step (2))
In the present invention, the isocyanate compound impregnated in the cleaning blade preform formed from the polyurethane resin has one or more isocyanate groups in the molecule.

  In the present invention, when the cleaning blade preliminary body is impregnated with the isocyanate compound solution, the cleaning blade may be a single body or may be joined to the support member.

  Of the cleaning blade preliminary body, the portion impregnated with the isocyanate compound solution may be a part or all of the cleaning blade preliminary body, but the cleaning blade includes at least an end portion where the cleaning blade and the toner carrier are in contact with each other. It is necessary to be unwilling.

  The impregnation of the cleaning blade with the isocyanate compound solution is performed, for example, by immersing the cleaning blade preliminary body in an isocyanate compound alone or an isocyanate compound solution diluted with an organic solvent.

  It is also possible to impregnate the cleaning blade preliminary body with the isocyanate compound solution by bringing the isocyanate compound into contact with the cleaning blade preliminary body in a liquid state and leaving it to stand.

  As the organic solvent for diluting the isocyanate compound, those having no active hydrogen capable of reacting with the isocyanate compound are used. Specifically, methyl ethyl ketone (MEK), toluene, tetrahydrofuran (THF), ethyl acetate, butyl acetate and the like are used. Can be mentioned. The dilution factor is preferably 2 times or less.

  After the cleaning blade preliminary body is impregnated with the isocyanate compound solution for a predetermined time, the isocyanate compound remaining on the surface of the cleaning blade is wiped off. In the production method of the present invention, the cleaning blade preliminary body is impregnated with an isocyanate compound to the extent that the cleaning blade preliminary body and the isocyanate compound can sufficiently react in step (3), regardless of how to wipe. Then, the reaction between the impregnated isocyanate compound, the cleaning blade preliminary body, and moisture in the air is allowed to proceed at room temperature. The progress of the reaction may occur during the impregnation, and the degree of the reaction can be controlled by adjusting the reaction temperature, the reaction time, and the standing environment. Preferably, in the step (3), it is allowed to stand at 25 to 35 ° C. and 50 to 70% humidity for 24 hours or more.

  In order to make the thickness of the cured layer of the cleaning blade finally obtained within a desired range, the impregnation time of the isocyanate compound solution is preferably 2 minutes or more, and more preferably 3 minutes or more. Further, it is preferably 15 minutes or less, and more preferably 10 minutes or less in consideration of mass productivity.

  The impregnation temperature may be any temperature at which the isocyanate compound solution exists as a liquid, and specifically, 45 ° C. or higher is preferable, and 60 ° C. or higher is more preferable. Further, in order to suppress thermal deterioration of the isocyanate compound and evaporation of the diluted solvent, the temperature is preferably 100 ° C. or lower, and more preferably 90 ° C. or lower.

(Combination of polyurethane resin raw materials)
In the present invention, the manner of impregnation with the isocyanate compound solution differs depending on the crosslinked form of the polyurethane resin in the step (1). For example, a polyurethane resin having a high weight average molecular weight of a polyol used as a raw material has a low crosslinking density, and thus is easily impregnated with an isocyanate compound solution. Further, when a nurating catalyst or the like is added to the polyurethane resin, the surface hardness tends to increase due to the influence of the catalyst.

  On the other hand, the isocyanate compound preferably has a low molecular weight. When the molecular weight is high, the polyurethane resin tends to be difficult to be impregnated with the isocyanate compound solution. Thus, as a polyurethane resin raw material and an isocyanate compound, those having a desired combination can be used according to the required characteristics of the cleaning blade.

(Hardness of hardened layer)
In order to make the dynamic hardness at the contact portion of the cured layer formed by the reaction of the polyurethane resin with the isocyanate compound, etc., after the treatment at 80 ° C., the impregnation time of the isocyanate compound solution should be 2 minutes or more. 3 minutes or more are more preferable. Further, it is preferably 15 minutes or less, and more preferably 10 minutes or less in consideration of mass productivity.

The dynamic hardness at the contact surface of the cured layer formed by the reaction of the polyurethane resin with an isocyanate compound or the like needs to be 0.21 mN / μm ² or more and 1.50 mN / μm ² or less. When the dynamic hardness is less than 0.21 mN / μm ² , the friction with the toner carrier increases and the cleaning blade is rolled, and when it exceeds 1.50 mN / μm ² , the toner carrier is damaged by the cleaning blade. Further, the dynamic hardness on the surface of the contact portion is preferably 0.25 mN / μm ² or more, and preferably 0.3 mN / μm ² or less, at which the coefficient of friction with the toner carrier is lowered.

The amount of change in dynamic hardness of the hardened layer from the surface to the 0.1 mm portion on the inner side in the thickness direction needs to be −0.12 mN / μm ² or more and −0.04 mN / μm ² or less. Here, “the amount of change in dynamic hardness from the surface to the 0.1 mm portion on the inner side in the thickness direction” represents (dynamic hardness at the position of 0.1 mm on the inner side in the thickness direction) − (dynamic hardness of the hardened layer surface). When the change in dynamic hardness is less than −0.12 mN / μm ² , the hardness difference inside the cured layer becomes large, and the cleaning blade tends to be chipped. On the other hand, if the amount of change in dynamic hardness exceeds −0.04 mN / μm ² , the entire cleaning blade becomes hard, rubber elasticity is lost, and adhesion to the toner carrier is impaired.

  In order to make the dynamic hardness change amount from the surface of the hardened layer to the inner 0.1 mm portion within a desired range, the hardness change amount can be adjusted by changing the dilution ratio of the isocyanate compound with the solvent. The dilution factor is preferably 2 times or less, and more preferably 1.5 times or less.

Further, the amount of change in dynamic hardness from the surface of the cured layer to the inner 0.1 mm portion is preferably −0.1 mN / μm ² or more, more preferably −0.06 mN / μm ² or less.

  Further, the amount of change in dynamic hardness in the portion from the surface of the cured layer to the inside of 0.1 mm is preferably smaller from the viewpoint of chipping of the cleaning blade, wrinkles, etc., and diluted with a solvent than when treated with an isocyanate compound alone. The amount of change is smaller when the isocyanate compound is used.

The dynamic hardness of the portion other than the hardened layer of the cleaning blade needs to be 0.05 mN / μm ² or more and 0.16 mN / μm ² or less. Moreover, 0.09 mN / μm ² or more is preferable, and 0.14 mN / μm ² or less is more preferable. The range of the dynamic hardness in the portion other than the cured layer of the cleaning blade is an international rubber hardness (IRHD) range of a cleaning blade (cleaning blade preliminary body) based on a polyurethane resin before the cured layer is formed. In this case, the obtained cleaning blade is flexible and rich in rubber elasticity as a whole, and good adhesion between the toner carrier and the cleaning blade can be realized, and the toner carrier is the cleaning blade. Can be prevented from being damaged.

  As described above, in the cleaning blade of the present invention, the predetermined cured layer is formed only in the contact portion with the toner carrier, so that the friction of the free length portion is maintained while maintaining the rubber elasticity. The coefficient is low, the surface hardness is high, the hardness difference between the surface and the inside of the cured layer is small, and good sliding characteristics and durability are realized.

(Electrophotographic equipment)
FIG. 4 shows a schematic configuration of an electrophotographic apparatus having an electrophotographic photosensitive member. In FIG. 4, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow about an axis. In the rotation process, the electrophotographic photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3 and then exposed to exposure means (not shown) such as slit exposure and laser beam scanning exposure. The exposure light 4 is received. In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor 1.

  The electrostatic latent image formed in this way is then developed with toner by the developing means 5, and the developed toner developed image is transferred between the photosensitive member 1 and the transfer means 6 from a paper supply unit (not shown). The image is sequentially transferred by the transfer means 6 onto the transfer material 7 fed under a condition synchronized with the rotation of the photoreceptor 1.

  The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, thereby being printed out as a copy (copy).

  The surface of the photoreceptor 1 after the image transfer is cleaned by removing the transfer residual toner by the cleaning blade 9 of the present invention, and used repeatedly for image formation.

  The electrophotographic photosensitive member of the present invention can be used not only in electrophotographic copying machines but also widely in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

  The present invention will be described in more detail with reference to the following examples, but these examples do not limit the present invention.

[Example 1]
In the experiment of the present invention, as the polyurethane resin raw material, the isocyanate compound is MDI (4,4, -diphenylmethane diisocyanate: manufactured by Nippon Polyurethane Industry), the polyol (butylene hexylene adipate-based polyester polyol), and the crosslinking material 1, 4- A mixed liquid of butanediol and trimethylolpropane (mass ratio 65:35) was used. These raw materials were mixed so that the hydroxyl group / NCO molar ratio was 0.8 and used for molding. The polyurethane resin was molded using a centrifugal molding machine heated to 130 ° C. and cured for 30 minutes. After forming into a sheet shape using the polyurethane resin raw material, it was cut and bonded to a plate-like support member to form a cleaning blade (sheet thickness 2.0 mm, free length 10 mm). Next, this was cut into a predetermined size to obtain a cleaning blade preliminary body. The obtained cleaning blade preliminary body had an international rubber hardness (IRHD) of 74 °. The hardness (IRHD) was measured based on JIS K 6253 using a Wallace microhardness meter manufactured by Wallace (HW WALLACE).

  The polyurethane resin cleaning blade preliminary body obtained was immersed in an isocyanate (MDI) / butyl acetate (2/1) (isocyanate concentration 66%) tank at 80 ° C. for 3 minutes, and then the polyurethane resin blade was pulled up from the MDI tank. Excess MDI was wiped off. Thereafter, the cleaning blade 1 was prepared by aging in an NN environment for 2 days (L1: 5 mm, L2: 2 mm).

  When the cross section of the toner carrier contact portion of the obtained cleaning blade 1 was observed with an optical microscope, the cured layer was observed as a cloudy layer, and the thickness of the cured layer was 0.20 mm.

  The dynamic hardness was measured from the surface and the cut surface of the toner carrier contact portion which is the isocyanate treatment portion (the portion where the isocyanate compound solution was impregnated) of the cleaning blade (FIG. 2). The cut surface was cut in the vicinity of the toner carrier contact portion, and the dynamic hardness was measured at regular intervals from the surface side. FIG. 3 shows changes in dynamic hardness toward the inner side in the thickness direction at arbitrary three points on the surface of the cured layer. “Depth” in FIG. 3 represents the depth toward the inside in the thickness direction, and the dynamic hardness when the depth is 0 mm represents the dynamic hardness on the surface of the hardened layer. In this embodiment, the thickness of the hardened layer is 0.2 mm. However, in FIG. 3, for the sake of convenience, the curve of the dynamic hardness exceeding 200 μm is extrapolated. For the measurement, “Shimadzu Dynamic Ultra Hardness Tester” DUH-W201S manufactured by Shimadzu Corporation was used. As the indenter, a 115 ° triangular cone indenter was used, and the dynamic hardness was obtained from the following formula.

Dynamic hardness: DH = α x P / D ²
α: Constant according to indenter shape, P: Test test force (mN), D: Indenter penetration into sample (pushing depth) (μm), α = 3.8484, P = 0.5.

  The “dynamic hardness of the hardened layer surface” was obtained by measuring three arbitrary points at the position of the hardened layer surface in FIG. 2 and averaging them (FIG. 3). “The amount of change in the dynamic hardness of the hardened layer from the surface to the 0.1 mm portion on the inner side in the thickness direction” is the hardness at the cut surface, and the cut position near the contact portion (from the end 16 to the free length direction 11 3 mm), the hardness was measured at three points from the surface to the inner side in the thickness direction at intervals of 0.05 mm up to 0.1 mm, and the average was obtained (FIG. 3). The “dynamic hardness in the portion other than the hardened layer of the cleaning blade” was determined by measuring three arbitrary points at the position of the untreated portion and averaging them.

  Next, the cleaning blade 1 was incorporated into a Canon copier color laser copier 5000, and a mounting test was conducted. As a result, even after 100,000 sheets were printed, good cleaning performance was obtained.

[Example 2]
A cleaning blade 2 was prepared in the same manner as in Example 1 except that the concentration of the isocyanate compound was 80%, and its characteristics were evaluated.
When a mounting test was performed in the same manner as the cleaning blade 1, the cleaning performance was good even after 100,000 sheets were printed.

[Example 3]
A cleaning blade 3 was prepared in the same manner as in Example 1 except that the isocyanate compound was not diluted with a solvent and used alone (isocyanate concentration 100%), and its characteristics were evaluated.
When a mounting test was performed in the same manner as the cleaning blade 1, although it had good cleaning properties even after printing 100,000 sheets, wrinkles remained on the blade after durability.

[Comparative Example 1]
A cleaning blade 4 was prepared in the same manner as in Example 1 except that the dilution amount of the isocyanate compound was 50%, and the characteristics thereof were evaluated.
When a mounting test was performed in the same manner as the cleaning blade 1, when 10,000 sheets were printed, the cleaning blade fell and cleaning could not be performed.

[Comparative Example 2]
A cleaning blade 5 was prepared in the same manner as in Example 1 except that it was not subjected to isocyanate treatment (impregnation treatment with an isocyanate compound solution), and its characteristics were evaluated.
When a mounting test was performed in the same manner as the cleaning blade 1, the cleaning blade was rolled immediately after the start of rotation of the photosensitive drum, and cleaning could not be performed.
[Comparative Example 3]
The polyurethane resin was molded using a centrifugal molding machine heated to 130 ° C., cured for 20 minutes and molded, and a cleaning blade 6 was prepared in the same manner as in Example 1 except that the isocyanate treatment was not performed. The resulting cleaning blade had an international rubber hardness (IRHD) of 80 °. The characteristics of the cleaning blade 6 were evaluated in the same manner as in Example 1.

When a mounting test was performed in the same manner as the cleaning blade 1, the cleaning blade was rolled immediately after the start of rotation of the photosensitive drum, and cleaning could not be performed.
The results obtained above are shown in Table 1.

  In Table 1, “dynamic hardness at the contact portion” means “dynamic hardness of the surface of the hardened layer” and “dynamic hardness change per unit depth (0.1 mm)” means “thickness of the hardened layer from the surface. The “dynamic hardness change amount up to a 0.1 mm portion on the inner side in the direction” and “dynamic hardness other than in the hardened layer” represent “dynamic hardness in a portion other than the hardened layer of the cleaning blade”.

From the results shown in Table 1, the present invention has (a) a cured layer as the outermost surface layer of the contact portion, and (b) a dynamic hardness of the cured layer surface of 0.21 mN / μm ² or more and 1.50 mN / μm ^2. Hereinafter, (c) the amount of dynamic hardness change from the surface to the 0.1 mm portion on the inner side in the thickness direction of the cured layer is −0.12 mN / μm ² or more and −0.04 mN / μm ² or less, (d) the cleaning by dynamic hardness in the blade portion other than the hardened layer of 0.05mN / μm ² or more 0.16mN / μm ² or less, and the cleaning blade satisfy, it was found to have excellent cleaning properties (example 1 3, Comparative Examples 1-3).

  Further, under the conditions of this example, the isocyanate compound solution used in step (2) is changed in dilution ratio so that the isocyanate compound concentration is 66% or more, whereby the above-mentioned hardness conditions (b) to (d) are satisfied. It was found that a blade was obtained.

It is a schematic diagram for demonstrating the cleaning blade of this invention. Dynamic hardness measurement position It is a figure which shows the depth dependence of dynamic hardness. It is a figure which shows an example of the electrophotographic apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Longitudinal direction 11 Free length direction 12 Width direction 13 Free length part 14 Contact part 15 Hardened layer 16 End part (use contact)
L1 Length in the free length direction of the hardened layer L2 Length in the thickness direction of the hardened layer L3 Width of the cleaning blade T Thickness of the hardened layer

Claims (5)

A cleaning blade made of polyurethane resin that has a contact portion that contacts the toner carrier in part and that cleans and removes toner remaining on the toner carrier,
(A) having a hardened layer having a thickness of 0.1 mm or more as the outermost surface layer of the contact portion;
(B) Dynamic hardness of the hardened layer surface is 0.21 mN / μm ² or more and 1.50 mN / μm ² or less,
(C) The amount of change in dynamic hardness from the surface to the 0.1 mm portion on the inner side in the thickness direction of the cured layer is −0.12 mN / μm ² or more and −0.04 mN / μm ² or less,
(D) A cleaning blade having a dynamic hardness of 0.05 mN / μm ² or more and 0.16 mN / μm ² or less in a portion other than the hardened layer of the cleaning blade.   The cleaning blade according to claim 1, wherein the thickness of the hardened layer is 0.12 mm or more and 1.2 mm or less and 70% or less of the thickness of the cleaning blade. It is a manufacturing method of the cleaning blade according to claim 1 or 2,
(1) manufacturing a cleaning blade preliminary body made of polyurethane resin;
(2) impregnating at least a part of the cleaning blade preform with an isocyanate compound solution;
(3) A process for producing a cleaning blade, comprising: a step of reacting the cleaning blade preliminary body with the isocyanate compound to provide a cured layer on the surface of the cleaning blade preliminary body to form a cleaning blade.   The method for producing a cleaning blade according to claim 3, wherein the isocyanate compound solution is obtained by diluting an isocyanate compound with an organic solvent.   An electrophotographic apparatus comprising the cleaning blade according to claim 1, an electrophotographic photosensitive member, a charging unit, an image exposing unit, a developing unit, and a transfer unit.

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