JP2015187650A - image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deterioration in removal performance.SOLUTION: An image forming apparatus includes an image holding body 31 that rotates to hold an image on the lateral face, and a removal member 361 that removes a material attached to the lateral face. The lateral face of the image holding body 31 is formed of a first material, which has a loss tangent of 0.015 or more and 0.035 or less when given a vibration of 0.5 Hz at 28°C. The removal member 361 includes a contact part 3611 that is formed of a second material having a value of 100% modulus of 7 mega Pascal or more and is in contact at a contact point with an area on the lateral face moved to the upper side in the gravity direction, and a support part 3612 that is formed of a third material having a lower hardness than that of the second material and supports the contact part 3611 from the opposite side of the contact point. The normal vector of an opposing face F1 arranged opposite to the upstream side of the contact point in a direction of rotation of the image holding body 31 does not include a component directed to the upper side in the gravity direction.

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses an electrophotographic photosensitive member surface having a surface with an HU (Universal Hardness Value) of 150 N / mm 2 or more and 220 N / mm 2 or less and an elastic deformation rate Wo of 44% or more and 65% or less. An image forming apparatus having a fatty acid metal salt supply means for supplying a fatty acid metal salt and having a cleaning blade having a rubber hardness of 78 degrees or more and 99 degrees or less is described.

JP 2005-164775 A

  An object of this invention is to suppress degradation of removal performance.

  An image forming apparatus according to a first aspect of the present invention includes an image carrier that rotates to hold an image on a side surface, and a removal member that removes a substance attached to the side surface, and the side surface of the image carrier. Is formed of a first material having a loss tangent of 0.015 or more and 0.035 or less when a vibration of 0.5 hertz is applied at 28 degrees Celsius, and the removal member contacts the side surface at a contact point. A contact portion and a support portion that supports the contact portion from the opposite side of the contact point, and the contact portion is formed of a second material having a 100% modulus value of 7 megapascals or more. The portion is formed of a third material whose hardness is lower than that of the second material, and the normal vector of the facing surface facing the upstream side of the contact point in the rotation direction of the image carrier is directed upward in the direction of gravity. It is characterized by not containing any components.

（一般式（１）中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵、及び、Ｒ⁶は、それぞれ同一であっても異なっていてもよく、水素原子、アルキル基、アルコキシル基、ハロゲン原子、又は、置換若しくは無置換のアリ−ル基を示す。ｍ及びｎは０又は１を示す。）

（一般式（２）及び一般式（３）中、Ｒ⁷、Ｒ⁸、Ｒ⁹、及び、Ｒ¹⁰は、各々独立に、水素原子、ハロゲン原子、炭素数１以上６以下のアルキル基、炭素数５以上７以下のシクロアルキル基、又は、炭素数６以上１２以下のアリール基を表す。Ｘは、フェニレン基、ビフェニレン基、ナフチレン基、直鎖若しくは分岐アルキレン基、又は、シクロアルキレン基を表す。） An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the contact point is in a region of the side surface that is moving in the direction of gravity.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image carrier has a component in which a normal vector at the contact point on the side surface is directed upward in the gravity direction. It is not included.
The image forming apparatus according to a fourth aspect of the present invention is the image forming apparatus according to any one of the first to third aspects, wherein the first material has a butadiene structure represented by the following general formula (1) having a charge transporting ability. And a polycarbonate copolymer containing a repeating unit represented by the following general formula (2) and a repeating unit represented by the following general formula (3).

(In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ may be the same or different, and each represents a hydrogen atom, an alkyl group, an alkoxyl group, A halogen atom or a substituted or unsubstituted aryl group, and m and n each represents 0 or 1)

(In General Formula (2) and General Formula (3), R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, carbon A cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 12 carbon atoms, X represents a phenylene group, a biphenylene group, a naphthylene group, a linear or branched alkylene group, or a cycloalkylene group. .)

According to the first and fourth aspects of the invention, it is possible to suppress the deterioration of the removal performance as compared with the case where this configuration is not provided.
According to the second and third aspects of the invention, the removed substance can be made difficult to deposit on the side surface of the image carrier.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the structure of a drum cleaner. It is the figure which expanded the area | region III in FIG. It is a figure for demonstrating arrangement | positioning of the removal member with respect to an image holding body. It is a figure which shows the structure of the drum cleaner in a modification. It is a figure which shows the structure of the drum cleaner in a modification.

1. Embodiment 1-1. 1 is a diagram showing an overall configuration of an image forming apparatus 1 according to an embodiment of the present invention.
Hereinafter, in order to explain the arrangement of each component of the image forming apparatus 1, the space in which each component is arranged is expressed as an xyz right-handed coordinate space. Of the coordinate symbols shown in the figure, a symbol in which a black circle is drawn in a white circle represents an arrow heading from the back side to the near side. A direction along the x-axis in space is referred to as an x-axis direction. Of the x-axis directions, the direction in which the x component increases is referred to as + x direction, and the direction in which the x component decreases is referred to as -x direction. For the y and z components, the y-axis direction, + y direction, -y direction, z-axis direction, + z direction, and -z direction are defined according to the above definition.

As illustrated in FIG. 1, the image forming apparatus 1 includes a developing unit 13, a transfer unit 14, a fixing unit 15, and a conveyance unit 16.
The conveyance part 16 has a container and a conveyance roll. The container stores paper P as a medium. The paper P stored in the container is taken out one by one by a transport roll according to an instruction from a control unit (not shown), and is transported to the transfer unit 14 via a paper transport path. The medium is not limited to paper, and may be a resin sheet, for example. In short, the medium may be any medium that can record an image on the surface.

  The developing unit 13 includes an image carrier 31, a charger 32, an exposure device 33, a developing device 34, a primary transfer roll 35, and a drum cleaner 36. The image carrier 31 is a photosensitive drum having a charge generation layer and a charge transport layer, and is rotated in the direction of an arrow D13 in the drawing by a driving unit (not shown).

  As a material for forming the side surface of the image carrier 31 (hereinafter referred to as a first material), a material having a loss tangent of 0.015 or more and 0.035 or less is used.

  Here, the loss tangent (hereinafter also referred to as “tan δ”) is a “loss tangent” defined in K6394-2007 “Vulcanized rubber and thermoplastic rubber—How to obtain dynamic properties”, and has a loss elastic modulus. And the storage elastic modulus. Loss tangent shows different values depending on measurement conditions such as material type and temperature. “δ” of tan δ is a loss angle. Here, the measurement condition is set to be when the vibration of 0.5 hertz is given at 28 degrees Celsius.

Specifically, examples of suitable materials as the first material include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5- Pyrazoline derivatives such as triphenyl-pyrazoline, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, N, N′-bis (3 , 4-dimethylphenyl) biphenyl-4-amine, tri (p-methylphenyl) aminyl-4-amine, aromatic tertiary amino compounds such as dibenzylaniline, N, N′-bis (3-methylphenyl) Aromatic tertiary diamino compounds such as -N, N'-diphenylbenzidine, 3- (4'-dimethylaminophenyl) -5,6-di- (4'-methoxyphene) L) 1,2,4-triazine derivatives such as-1,2,4-triazine, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, and quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline Benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, N -Carbazole derivatives such as ethylcarbazole, hole transport materials such as poly-N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and broanthraquinone, tetraanoquinodimethane compounds, 2,4,7-trinitro Fluorenone, 2,4,5,7-tetranitro-9-fluore Examples thereof include fluorenone compounds such as non, electron transport materials such as xanthone compounds and thiophene compounds, and polymers having a group consisting of the above compounds in the main chain or side chain. In addition, the first material preferably includes a compound having a butadiene structure represented by the following general formula (1) having a charge transporting ability.

In this general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxyl group, A halogen atom or a substituted or unsubstituted aryl group is shown. m and n represent 0 or 1.

In addition, as the first material, for example, a known resin may be used as the binder resin (binder resin), or a resin formed as an electrically insulating film may be used. As the binder resin used for the first material, for example, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, Poly-N -Carbazole, polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxymethyl cellulose Vinylidene polymer waxes chloride, polyurethanes, and the like. In particular, the first material may include a polycarbonate copolymer including a repeating unit represented by the following general formula (2) and a repeating unit represented by the following general formula (3).

In these general formulas (2) and (3), R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, A cycloalkyl group having 5 to 7 carbon atoms or an aryl group having 6 to 12 carbon atoms is represented. X represents a phenylene group, a biphenylene group, a naphthylene group, a linear or branched alkylene group, or a cycloalkylene group.

  The charger 32 charges the surface of the image carrier 31. The exposure device 33 includes a laser light source, a polygon mirror, and the like (both not shown), and after the laser light corresponding to the image data is charged by the charger 32 under the control of a control unit (not shown). Irradiation toward the image carrier 31. Thereby, the latent image is held on the side surface of the image holding body 31.

  Note that the image data may be acquired from an external device by the image forming apparatus 1 via a communication unit (not shown). The external device is, for example, a reading device that reads an original image or a storage device that stores data indicating an image. The developing device 34 supplies the developer to the image carrier 31. As a result, an image is formed (developed) on the image carrier 31.

  The primary transfer roll 35 generates a predetermined potential difference at a position where the intermediate transfer belt 41 of the transfer unit 14 faces the image carrier 31, and the image is transferred to the intermediate transfer belt 41 by this potential difference. The drum cleaner 36 removes untransferred toner remaining on the surface of the image carrier 31 after the image is transferred, and neutralizes the surface of the image carrier 31.

  The transfer unit 14 includes an intermediate transfer belt 41, a secondary transfer roll 42, a belt transport roll 43, a backup roll 44, and a belt cleaner 49, and an image formed by the developing unit 13 is transferred to a sheet P It is a transfer part to transfer to. The intermediate transfer belt 41 is an endless belt member, and the belt conveyance roll 43 and the backup roll 44 stretch the intermediate transfer belt 41. At least one of the belt conveyance roll 43 and the backup roll 44 is provided with a drive unit (not shown), and moves the intermediate transfer belt 41 in the direction of arrow D14 in FIG. Note that the belt conveyance roll 43 or the backup roll 44 that does not have a driving unit rotates as the intermediate transfer belt 41 moves. As the intermediate transfer belt 41 moves and rotates in the direction of arrow D14 in FIG. 1, the image on the intermediate transfer belt 41 is moved to a region sandwiched between the secondary transfer roll 42 and the backup roll 44.

  The secondary transfer roll 42 transfers the image on the intermediate transfer belt 41 onto the paper P conveyed from the conveyance unit 16 by a potential difference with the intermediate transfer belt 41. The belt cleaner 49 removes untransferred toner remaining on the surface of the intermediate transfer belt 41. Then, the transfer unit 14 or the conveyance unit 16 conveys the paper P on which the image is transferred to the fixing unit 15. The fixing unit 15 fixes the image transferred onto the paper P by heating.

1-2. Configuration of Drum Cleaner FIG. 2 is a diagram illustrating a configuration of the drum cleaner 36. As shown in FIG. 2, the drum cleaner 36 includes a case 360, a removing member 361, and a holding member 362. In addition, the drum cleaner 36 may have a mechanism for discharging the surface of the image carrier 31 or a mechanism for supplying a lubricant to the surface.

  The case 360 is a housing having an opening on the side facing the image carrier 31 and includes a holding member 362 fixed to the ceiling plate. The holding member 362 holds one end of the removing member 361 and exposes the other end from the opening of the case 360 to determine a predetermined pressure (hereinafter referred to as contact pressure) and a predetermined angle (hereinafter referred to as contact angle). Then, the image holding member 31 is brought into contact. As shown in FIG. 2, the angle θ between the tangential plane at the contact point of the image carrier 31 and the direction in which the contact portion 3611 of the removal member 361 extends is the contact angle.

  The removing member 361 is a so-called two-layer cleaning blade, and includes a contact portion 3611 and a support portion 3612. The contact part 3611 contacts the image carrier 31 and removes substances such as toner adhering to the surface of the image carrier 31. The support part 3612 supports the contact part 3611 from the side opposite to the point where the contact part 3611 contacts the image carrier 31 (hereinafter referred to as a contact point). The substance scraped off by the contact portion 3611 of the removing member 361 is accommodated in the case 360 and removed from the image forming apparatus 1 during maintenance.

  The holding member 362 shown in FIG. 2 holds the support portion 3612 side of the removal member 361, but may hold the contact portion 3611 side, or both the contact portion 3611 and the support portion 3612. The removal member 361 may be held in contact with.

As the materials for the contact portion 3611 and the support portion 3612, those satisfying the following rules are used. That is, the material constituting the contact portion 3611 (hereinafter referred to as the second material) is a material adjusted so that the value of 100% modulus is 7 megapascals or more. The value of 100% modulus is “predetermined tensile stress” defined in JIS K6251-2010 “Vulcanized rubber and thermoplastic rubber-Determination of tensile properties”. When 100% elongation is given to a test piece Is the value obtained by dividing the tensile force by the initial cross-sectional area of the test piece. Here, 25 degreeC is employ | adopted as test temperature. Thereby, wear of contact part 3611 constituted by the 2nd material is controlled.
The material constituting the support portion 3612 (hereinafter referred to as a third material) is a material having a hardness lower than that of the second material.

1-3. Arrangement of Removal Member FIG. 3 is an enlarged view of region III in FIG. The image carrier 31 is rotated in the direction of the arrow D13, and the contact portion 3611 of the removing member 361 is in contact with the side surface F0 of the image carrier 31 at the contact point C.
The removal member 361 has a facing surface F1 at the tip. The facing surface F <b> 1 is a surface facing the upstream side of the contact point C in the rotation direction of the image carrier 31.

Here, the arrangement of the removal member 361 is determined so that the contact point C and the facing surface F1 satisfy the following two conditions.
(Condition a) The contact point C is in an area of the side surface of the image carrier 31 that is moving above the gravity direction (+ z direction). That is, the contact point C is on the side surface on the side where the image carrier 31 rises.
(Condition b) The normal vector N1 of the facing surface F1 does not include a component directed upward in the gravity direction (+ z direction). That is, the facing surface F1 is a downward surface.

  FIG. 4 is a diagram for explaining the arrangement of the removing member 361 with respect to the image carrier 31. The range in which the removal member 361 is disposed with respect to the image carrier 31 is determined by the two conditions described above. According to the condition a, the contact point C is on the side surface on the side where the image carrier 31 rises, and thus is within the range of the region R1 shown in FIG. According to the condition b, the facing surface F1 is a downward surface and is within the range of the region R2 shown in FIG. In order to satisfy both the condition a and the condition b, the removing member 361 contacts the contact point C in the region where the region R1 and the region R2 overlap. That is, in FIG. 4, the removal member 361 from the removal member 361-0 to the removal member 361-5 is the disposing member 361 that can be arranged.

  Since the contact point C is limited to the side surface on the side where the image carrier 31 rises, when a substance such as toner adhering to the side surface of the image carrier 31 is peeled off by the removal member 361, this substance is applied to the removal member 361. It is prevented from falling and is less likely to stay between the removal member 361 and the image carrier 31. Further, since the facing surface F1 is a downward surface, the peeled-off substance is difficult to be placed on the facing surface F1, and the possibility of staying between the removal member 361 and the image carrier 31 is reduced. As described above, the provision of the condition a and the condition b reduces the possibility that the material peeled from the side surface of the image carrier 31 stays between the removal member 361 and the image carrier 31. Wear, deformation, and vibration of the removal member 361 are suppressed. And since these are suppressed, degradation of removal performance reduces.

2. Test Example 2-1. Test configuration Tests 1 to 11 were performed below. As shown in Table 1, each apparatus used in the test has the orientation of the facing surface F1, the first material used for the side surface of the image carrier 31, the loss tangent of the first material, and the 100% modulus of the contact portion 3611. Each is characterized by a value.
As the first material, materials M1, M2, M3, and M4 were used. Material M1 was made according to the following procedure.

  100 parts by mass of zinc oxide (average particle size: 70 nm, manufactured by Teika, specific surface area value: 15 m 2 / g) is stirred and mixed with 500 parts by mass of methanol, and KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.75 is used as a silane coupling agent. Part by mass was added and stirred for 2 hours. Thereafter, methanol was distilled off under reduced pressure, and baking was performed at 120 ° C. for 3 hours to obtain silane coupling agent surface-treated zinc oxide particles.

60 parts by mass of the surface-treated zinc oxide particles, 1.2 parts by mass of a reactive acceptor substance containing an anthraquinone structure represented by formula (4), and blocked isocyanate (Sumidule 3173, Sumitomo Bayern Urethane as a curing agent) 13.5 parts by mass) and 15 parts by mass of butyral resin (BM-1, Sekisui Chemical Co., Ltd.) dissolved in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone are mixed. Dispersion was performed for 4 hours with a sand mill using glass beads having a diameter of 1 mm to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added as a catalyst, and a coating liquid for forming an undercoat layer is added. Obtained. The viscosity of the coating solution for forming the undercoat layer at the coating temperature (24 ° C.) was 235 mPa · s.
This coating solution was applied onto an aluminum substrate having a diameter of 30 mm at a coating speed of 220 mm / min by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

  Next, as a charge generation material, at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-ray, 15 parts by mass of hydroxygallium phthalocyanine crystals having strong diffraction peaks at 25.1 ° and 28.3 °, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and n-butyl alcohol A mixture of 300 parts by mass was dispersed for 4 hours with a sand mill using glass beads having a diameter of 1 mm to obtain a coating solution for forming a charge generation layer. The viscosity at the coating temperature (24 ° C.) of the coating solution for forming a charge generation layer was 1.8 mPa · s. This coating solution was dip-coated on the undercoat layer by a dip coating method at a coating speed of 65 mm / min and dried at 150 ° C. for 10 minutes to obtain a charge generation layer.

Next, 8 parts by mass of tetrafluoroethylene resin particles (average particle size: 0.2 μm) and 0.01 parts by mass of a fluorinated alkyl group-containing methacrylic copolymer (weight average molecular weight 30000), 4 parts by mass of tetrahydrofuran, toluene The mixture was kept at a liquid temperature of 20 ° C. together with 1 part by mass and stirred for 48 hours to obtain a tetrafluoroethylene resin particle suspension A.
Next, a compound having the following structural formula 1 as a charge transport material (in general formula (1), n = 1, m = 1, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are all 4 parts by mass of H, tris [4- (4,4-diphenyl-1,3-butadienyl) phenyl] amine) as a binder resin, R ⁷ and R in the following structural formula 2 (general formula (2)) ⁸ is a polycarbonate copolymer (viscosity average) composed of repeating units of the following structural formula 3 (in general formula (3), X is an isopropylidene group, R ⁹ and R ¹⁰ are all CH ₃ ) 6 parts by mass of molecular weight 40000), 0.1 part by mass of 2,6-di-t-butyl-4-methylphenol as an antioxidant are mixed, and 24 parts by mass of tetrahydrofuran and 11 parts by mass of toluene are mixed and dissolved. Thus, a mixed solution B was obtained. In addition, the polycarbonate copolymer which consists of the repeating unit of Structural formula 3 is a bisphenol C type polycarbonate.

  Dispersion after increasing the pressure to 500 kgf / cm 2 using a high pressure homogenizer (manufactured by Yoshida Kikai Kogyo Co., Ltd.) equipped with a penetrating chamber having a fine flow path after adding the A liquid to the B liquid and stirring and mixing. 5 ppm of fluorine-modified silicone oil (trade name: FL-100 manufactured by Shin-Etsu Silicone Co., Ltd.) was added to the solution obtained by repeating the treatment 6 times, and the mixture was sufficiently stirred to obtain a coating solution for forming a charge transport layer. This coating solution was applied onto the charge generation layer at a thickness of 24 μm and dried at 135 ° C. for 25 minutes to form a charge transport layer, thereby obtaining a target material M1.

The material M2 is a repeating structural formula in which the polycarbonate copolymer consisting of the repeating unit of the structural formula 3 among the substances constituting the binder resin among the procedures described above is used, and X in the general formula (3) is a cycloalkylene group. It was made according to the procedure changed to a polycarbonate copolymer consisting of units.
The material M3 was prepared by using a polycarbonate copolymer (bisphenol C-type polycarbonate) which does not include the repeating unit of the structural formula 2 but includes only the repeating unit of the structural formula 3 as the binder resin in the above-described procedure.
The material M4 contains 4 parts by mass of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine, which is a compound having the following structural formula 4 as a charge transport material, and the following structural formula 5 as a binder resin. It was prepared in accordance with the same procedure as described above, except that 6 parts by mass of bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 40000), which is the compound shown, was used.

  The material M5 has a loss tangent of 0.00 by reducing N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine and increasing bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 40000). The material was prepared according to the same procedure as that of the material M4, except that it was adjusted to be less than 015.

2-2. Evaluation Method For each test example, image quality and wear were evaluated. The evaluation was made in four stages of “excellent”, “good”, “difficult”, and “unsuitable” in order from the highest to the lowest, and those evaluated as “excellent” or “good” were judged as effective configurations.

  Image quality is evaluated by collecting 10,000 random charts with an image density of 1%, collecting an image with an image density of 100%, and immediately counting the number of streaks remaining on the side stripes of the image carrier 31. did. A case where the number of streaks was 0 was evaluated as “excellent”, a case where it was 2 or less was evaluated as “good”, a case where it was 3 or more and 5 or less was evaluated as “difficult”, and a case where 6 or more were observed as “unsuitable”.

The wear was evaluated by measuring the area of the worn portion of the contact portion 3611 after collecting 10,000 random charts having an image density of 1%. “Excellent” if the area is 5 square micrometers (μm ² ) or less, “Good” if the area is 10 square micrometers (μm ² ) or less, and “Difficult” if the area is 20 square micrometers (μm ² ) or less. Those exceeding 20 square micrometers (μm ² ) were evaluated as “unsuitable”.

2-3. Test Results As shown in Table 1, the evaluations for Test Examples 1 to 5 were “excellent” or “good” for both image quality and wear. In any of the configurations of Test Examples 1 to 5, the direction of the facing surface F1 is downward, and the first material forming the side surface of the image carrier 31 gives a vibration of 0.5 hertz at 28 degrees Celsius. Loss tangent was 0.015 or more and 0.035 or less, and the value of 100% modulus measured for the second material constituting the contact portion 3611 was 7 megapascals or more.

  Note that the direction of the facing surface F1 being downward means that the normal vector N1 of the facing surface F1 does not include a component upward in the gravity direction, that is, satisfies the above-described condition b. And about the test example which made the direction of the opposing surface F1 downward in Table 1, the position of the contact point C was determined so that all the conditions a mentioned above might be satisfy | filled.

  On the other hand, the configuration of Test Example 6 is “5.0 megapascal” in which the value of 100% modulus measured for the second material is less than 7 megapascals. Test Example 6 was evaluated as “unsuitable” for both image quality and wear. The configuration of Test Example 7 is “0.040” in which the loss tangent of the first material exceeds 0.035. Test Example 7 was evaluated as “difficult” for both image quality and wear. The configuration of Test Example 11 is “0.013” in which the loss tangent of the first material is less than 0.015. Test Example 11 was evaluated as “difficult” in terms of image quality.

In the configurations of Test Examples 8 to 10, the direction of the facing surface F1 is upward. Test Examples 8 to 10 were evaluated as “difficult” or “unsuitable” for both image quality and wear, except that the image quality of Test Example 8 was evaluated as “good”.

  From the above evaluation results, the configuration of the image forming apparatus 1 is such that the direction in which the facing surface F1 faces is downward, and the first material forming the side surface of the image holding member 31 vibrates at 0.5 degrees at 28 degrees Celsius. When the loss tangent when given is 0.015 or more and 0.035 or less, and the value of 100% modulus measured for the second material constituting the contact portion 3611 is 7 megapascals or more, image quality deterioration and wear Was found to be suppressed.

3. Modification The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Further, the following modifications may be combined.
3-1. Modification 1
In the embodiment described above, the image forming apparatus 1 has only one developing unit 13, but may have a plurality of developing units 13. In this case, the image forming apparatus 1 includes a corresponding image holding member 31, a charger 32, an exposure device 33, a developing device 34, a primary transfer roll 35, and a drum cleaner 36. As long as it has. The plurality of developing units 13 may form toner images of different colors. In this case, toner images of different colors are transferred onto the intermediate transfer belt 41 and a color image is formed on a medium such as paper P.

3-2. Modification 2
In the embodiment described above, the removing member 361 is used for the drum cleaner 36, but may be used for the belt cleaner 49. In this case, the removing member 361 may remove the substance attached to the intermediate transfer belt 41 instead of the image carrier 31. The image carrier 31 and the intermediate transfer belt 41 are both examples of an image carrier that holds an image formed on a medium.

3-3. Modification 3
In the embodiment described above, the contact portion 3611 and the support portion 3612 of the removal member 361 have the same length as illustrated in FIG. 2, but may have different lengths and shapes.
FIG. 5 is a diagram showing a configuration of the drum cleaner 36 in this modification. As illustrated in FIG. 5, the contact portion 3611 may be a member shorter than the support portion 3612.

3-4. Modification 4
In the above-described embodiment, the contact portion 3611 and the support portion 3612 are rectangular as viewed from the axial direction of the image carrier 31, but these shapes are not limited to a rectangle, and may be, for example, a triangle or a fan shape. FIG. 6 is a diagram showing the configuration of the drum cleaner 36 in this modification. Even in this case, it is only necessary that the arrangement of the removing member 361 is determined so as to satisfy the condition a and the condition b.

3-5. Modification 5
In the above-described embodiment, the removal member 361 is arranged so as to satisfy the condition a and the condition b. However, the arrangement of the removal member 361 may not satisfy the condition a. The removal member 361 only needs to be arranged so as to satisfy at least the condition b. That is, the facing surface F1 of the removing member 361 may be a downward surface.

3-6. Modification 6
In the embodiment and the modification described above, the removal member 361 is disposed so as to satisfy at least the condition b, but may be disposed so as to satisfy the following condition c.
(Condition c) Assuming that the normal vector of the side surface of the image carrier 31 at the contact point C is “normal vector N0”, the normal vector N0 does not include a component toward the gravity direction (+ z direction). That is, the contact point C is in the lower half of the side surface of the image carrier 31.
According to the condition c, the contact point C is on the side surface of the lower half of the image carrier 31 and is therefore within the range of the region R3 shown in FIG. Accordingly, it is estimated that the material removed from the side surface of the image holding member 31 by the removing member 361 easily falls and is difficult to deposit on the side surface.
When all of the conditions a, b, and c are satisfied, the removing member 361 contacts the contact point C in the region where the region R1, the region R2, and the region R3 overlap. That is, in FIG. 4, the removal member 361 that satisfies the above conditions is from the removal member 361-3 to the removal member 361-5.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 13 ... Developing part, 14 ... Transfer part, 15 ... Fixing part, 16 ... Conveying part, 31 ... Image carrier, 32 ... Charger, 33 ... Exposure device, 34 ... Developing apparatus, 35 ... Primary Transfer roller, 36 ... drum cleaner, 360 ... case, 361 ... removal member, 3611 ... contact portion, 3612 ... support portion, 362 ... holding member, 41 ... intermediate transfer belt, 42 ... secondary transfer roll, 43 ... belt conveying roll , 44 ... backup roll, 49 ... belt cleaner, C ... contact point, D13 ... arrow line, F0 ... side face, F1 ... opposite face, N0 ... normal vector, N1 ... normal vector, P ... paper, R1 ... area, R2 ... region, R3 ... region.

Claims (4)

An image carrier that rotates to hold the image on the side;
A removal member for removing the substance attached to the side surface,
The side surface of the image carrier is formed of a first material having a loss tangent of 0.015 or more and 0.035 or less when a vibration of 0.5 hertz is applied at 28 degrees Celsius,
The removal member is
A contact portion that contacts the side surface at a contact point;
A support portion that supports the contact portion from the opposite side of the contact point;
The contact portion is formed of a second material having a 100% modulus value of 7 megapascals or more;
The support is formed of a third material having a lower hardness than the second material;
The image forming apparatus, wherein the normal vector of the facing surface facing the upstream side of the contact point in the rotation direction of the image holding member does not include a component upward in the gravity direction. The contact point is
The image forming apparatus according to claim 1, wherein the image forming apparatus is in an area of the side surface that is moving in a gravitational direction. The image carrier is
The image forming apparatus according to claim 1, wherein the normal vector at the contact point on the side surface does not include a component that moves upward in the direction of gravity. The first material includes a compound having a butadiene structure represented by the following general formula (1) having charge transporting ability, a repeating unit represented by the following general formula (2), and a repeating represented by the following general formula (3). The image forming apparatus according to claim 1, further comprising: a polycarbonate copolymer including units.

(In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ may be the same or different, and each represents a hydrogen atom, an alkyl group, an alkoxyl group, A halogen atom or a substituted or unsubstituted aryl group, and m and n each represents 0 or 1)

(In General Formula (2) and General Formula (3), R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, carbon A cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 12 carbon atoms, X represents a phenylene group, a biphenylene group, a naphthylene group, a linear or branched alkylene group, or a cycloalkylene group. .)

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