JP6859664B2 - Belt member, belt member unit, and image forming apparatus - Google Patents

Description

The present invention relates to a belt member, a belt member unit, and an image forming apparatus.

In an image forming apparatus adopting an electrophotographic method, a belt member is applied to an intermediate transfer belt, a recording medium transport belt, and the like.

For example, Patent Document 1 states, "In a belt device having a belt that is suspended and bridged between at least two members including a drive roller and is rotated by driving the drive roller, the drive roller is rotationally driven. A belt device in which the gear is a hasba gear is disclosed.

Further, Patent Document 2 describes "an intermediate transfer belt having a photoconductor drum (developer image retainer) for holding a developer image and an elastic layer stretched and conveyed between a plurality of support rollers. An electrophotographic image forming apparatus including a primary transfer roller that press-contacts the photoconductor drum with a transfer belt sandwiched between them and transfers a developer image held on the photoconductor drum to the intermediate transfer belt. An image forming apparatus in which the primary transfer roller is harder than the intermediate transfer belt and is made of a conductive resin is disclosed.

Further, Patent Document 3 states that "a transport belt including a belt base material made of an elastic material and a coating layer covering the surface of the belt base material, wherein the volume resistivity of the coating layer is 10 ¹⁴ Ω · cm. less than a and, in the resistance of the conveyor belt when the covering layer unformed or more resistance after forming a coating layer, and the resistance of the conveyor belt after the coating layer formed 10 ⁴ Omega least 10 ¹¹ Omega below A "conveying belt" is disclosed.

Japanese Unexamined Patent Publication No. 11-160950 Japanese Unexamined Patent Publication No. 2011-128262 Japanese Unexamined Patent Publication No. 2004-354559

The subject of the present invention is that, as compared with the case where the belt member is composed of a single layer of a resin layer having an elastic modulus of 2000 MPa or more and 6000 MPa or less, the belt member is bridged in a state where tension is applied to a plurality of rolls in the image forming apparatus and other members. It is an object of the present invention to provide a belt member that suppresses the occurrence of image deviation that occurs when used for forming an image in a state of being arranged so as to form a nip with the belt member.

The above problem is solved by the following invention. That is,
The invention according to <1> is
An elastic layer that constitutes the inner peripheral surface and has a JIS-A hardness of 50 ° or more and 90 ° or less.
A resin layer that constitutes the outer peripheral surface and has an elastic modulus of 2000 MPa or more and 6000 MPa or less.
Belt member for an image forming apparatus having.

The invention according to <2> is
The belt according to <1> , wherein the arithmetic mean roughness Ra (JIS-B0601: 2001) on the inner peripheral surface is 2 μm or less, and the maximum height Rz (JIS-B0601: 2001) is 7 μm or less. Element.

The invention according to <3> is
The belt member according to <1> or <2> , wherein the average thickness of the resin layer is 50 μm or more and 70 μm or less.

The invention according to <4> is
The belt member according to any one of <1> to <3> , wherein the average thickness of the elastic layer is 300 μm or more and 600 μm or less.

The invention according to <5> is
The belt member according to any one of <1> to <4> , wherein the resin layer contains at least one resin selected from the group consisting of a polyimide resin and a polyamide-imide resin.

The invention according to <6> is
The belt member according to any one of <1> to <5> and
A plurality of rolls for hanging the belt member under tension, and
A belt member unit that is attached to and detached from the image forming apparatus.

The invention according to <7> is
Image holder and
A charging means for charging the surface of the image holder and
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image holder, and
A developing means that accommodates a developer containing toner and develops a static charge image formed on the surface of the image holder by the developer as a toner image.
The toner image having the belt member unit according to <6> , the toner image formed on the surface of the image holder is primarily transferred to the outer peripheral surface of the belt member, and the toner image transferred to the belt member is recorded as a recording medium. And the transfer means for secondary transfer to
An image forming apparatus comprising.

According to the invention according to <1> or <5> , tension is applied to a plurality of rolls in the image forming apparatus as compared with the case where the belt member is composed of a single layer of a resin layer having an elastic modulus of 2000 MPa or more and 6000 MPa or less. Provided is a belt member that is bridged in a state and is arranged so as to form a nip with another member and suppresses the occurrence of image deviation that occurs when the image is used for forming an image.
According to the invention according to <2> , tension is applied to a plurality of rolls in the image forming apparatus as compared with the case where the arithmetic mean roughness Ra of the inner peripheral surface exceeds 2 μm or the maximum height Rz exceeds 7 μm. Provided is a belt member that suppresses the occurrence of image deviation that occurs when the image is used for forming an image in a state where the belt member is bridged in a vertical state and arranged so as to form a nip with another member.
According to the invention according to <3> , as compared with the case where the average thickness of the resin layer is less than 50 μm, the plurality of rolls are stretched in the image forming apparatus while being stretched and between the resin layer and the other members. Provided is a belt member that suppresses the occurrence of image deviation that occurs when used for image formation in a state of being arranged so as to form a nip.
According to the invention according to <4> , as compared with the case where the average thickness of the elastic layer is less than 300 μm, the plurality of rolls are stretched in the image forming apparatus in a tensioned state and are bridged with other members. Provided is a belt member that suppresses the occurrence of image deviation that occurs when used for image formation in a state of being arranged so as to form a nip.

According to the invention according to <6> or <7> , tension is applied to a plurality of rolls in the image forming apparatus as compared with the case where a belt member composed of a single layer of a resin layer having an elastic modulus of 2000 MPa or more and 6000 MPa or less is applied. A belt member unit or image forming that suppresses the occurrence of image deviation that occurs when used for image formation in a state where it is hung and laid so as to form a nip with other members. Equipment is provided.

It is a schematic perspective view which shows an example of the belt member which concerns on this embodiment. It is sectional drawing which shows the cross section of the belt member shown in FIG. 1 enlarged. (A) is a schematic plan view showing an example of a circular electrode, and (B) is a schematic cross-sectional view thereof. It is a schematic block diagram which shows an example of the image forming apparatus which concerns on this embodiment. It is a schematic diagram which shows another example of the positional relationship between an image holder and a primary transfer roll in the image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows another example of the image forming apparatus which concerns on this embodiment.

Hereinafter, embodiments that are an example of the present invention will be described in detail.

<Belt member>
The belt member for the image forming apparatus according to the present embodiment has an elastic layer forming an inner peripheral surface and a resin layer forming an outer peripheral surface. The elastic layer has a JIS-A hardness of 50 ° or more and 90 ° or less, and the resin layer has an elastic modulus of 2000 MPa or more and 6000 MPa or less.

By having the above configuration, the belt member according to the present embodiment is arranged so as to be bridged in a state where tension is applied to a plurality of rolls in the image forming apparatus and to form a nip with other members. The occurrence of image misalignment that occurs when the image is used to form an image in this state is suppressed.
The reason can be inferred as follows.

Conventionally, a belt member has been used as various members in an image forming apparatus. For example, an intermediate in which a toner image on an image holder is transferred (primary transfer) and then transferred again on a recording medium (secondary transfer). When the toner image held on the transfer belt or the intermediate transfer body is secondarily transferred to the recording medium, the recording medium is conveyed in contact with the back surface (non-transfer surface) of the recording medium and a voltage is applied for the secondary transfer. It is used as various members such as a secondary transfer belt and a recording medium transfer belt that conveys a recording medium and applies a voltage for transfer in a mode in which a toner image on an image holder is directly transferred to the surface of the recording medium. ..
These belt members used in the image forming apparatus are usually laid across in a state where tension is applied to a plurality of rolls, and are installed so that the inner peripheral surface side comes into contact with these rolls.
In addition, it is often arranged so as to form a contact region (nip portion) with other members. For example, in the case of an intermediate transfer belt, a portion in contact with the image holder (that is, a primary transfer position of a toner image) or two. It is arranged so as to form a nip portion at a position where it comes into contact with the next transfer member (that is, a secondary transfer position of the toner image to the recording medium). A nip is formed at the position where the secondary transfer belt comes into contact with the intermediate transfer body (that is, the secondary transfer position of the toner image to the recording medium), and the recording medium transfer belt also comes into contact with the image holder (that is, the toner). It is arranged so as to form a nip portion at the transfer position of the image to the recording medium). When the belt member forms a contact region (nip portion) with the other member, the other member is in contact with the outer peripheral surface of the belt member, while facing the other member via the belt member (inside). The facing member is arranged on the peripheral surface side), and the nip portion is formed by arranging the belt member so as to be sandwiched between the two members.
In this way, the various belt members used in the image forming apparatus are bridged in a state where tension is applied to the plurality of rolls, and are sandwiched between the two members (the other member and the opposing member) to form a contact region (the other member and the opposing member). It is arranged and used to form a nip portion).

However, when the belt member is bridged and rotationally driven in a state where tension is applied to a plurality of rolls, the influence of uneven tension (belt tension) applied to the belt member and contact with the inner peripheral surface of the belt member. Due to the influence of the difference in the outer diameter of the roll in the axial direction (difference in the outer diameter of the roll), the tension applied to the belt member may fluctuate temporarily and locally, resulting in a tension difference. is there. Then, due to this tension difference, the speed fluctuation may occur temporarily and locally in the belt member that is rotationally driven.
On the other hand, in the nip portion, the belt member sandwiched between the two members is in a state of being compressed in the thickness direction, and the pressure applied to the belt member in the nip portion in the compression direction may vary.
Then, due to the effects of speed fluctuations that occur temporarily and locally in the belt member, pressure variations that occur in the nip portion, and the like, partial deviation (positional deviation) from the position that is originally intended to be controlled in the belt member occurs. If the toner image is transferred in a state where the position shift occurs, the image may shift as a result, that is, so-called image shift may occur.

On the other hand, in the belt member according to the present embodiment, the elastic layer having the JIS-A hardness in the above range constitutes the inner peripheral surface, and the resin layer having the elastic modulus in the above range constitutes the outer peripheral surface.
The fact that the elastic layer constituting the inner peripheral surface has the hardness in the above range means that the inner peripheral surface of the belt member has appropriate elasticity, and thus comes into contact with the inner peripheral surface. Excellent followability and followability to the member are exhibited. Therefore, in the nip portion, good followability is exhibited with respect to the opposing member that is in contact with the inner peripheral surface and applies pressure to the belt member, and if the pressure applied to the belt member in the nip portion varies. However, the occurrence of partial misalignment (positional misalignment) in the belt member is suppressed. In addition, good followability is exhibited even for a plurality of rolls over which the belt member is hung, and if the tension (belt tension) applied to the belt member becomes uneven or the rolls have an outer diameter difference in the axial direction. Even so, it is possible to suppress the occurrence of speed fluctuations in the belt member that is driven to rotate, and as a result, the occurrence of positional deviation in the belt member is suppressed.
Further, the fact that the resin layer constituting the outer peripheral surface has the elastic modulus in the above range means that the outer peripheral surface of the belt member has rigidity and is hard to be deformed. Therefore, even if the tension applied to the belt member (belt tension) becomes uneven or the roll has an outer diameter difference in the axial direction, the influence of the tension difference generated on the belt member due to the resin layer that is hard to be deformed is affected. It is reduced, and the occurrence of speed fluctuation in the belt member that is rotationally driven is suppressed. As a result, the occurrence of partial misalignment (positional misalignment) in the belt member is suppressed.
As described above, by suppressing the partial deviation (positional deviation) from the position to be originally controlled in the belt member, the occurrence of the deviation (image deviation) in the formed image is suppressed.

Next, the configuration of the belt member according to the present embodiment will be described in detail.

In the present embodiment, as shown in FIG. 1, the belt member 15 is formed in an endless shape. The endless belt member 15 is bridged over a plurality of rolls (rolls 131 and 132 in FIG. 1) in a state where tension is applied to form the belt member unit 150.
As shown in FIG. 2, the belt member 15 is composed of an elastic layer 15B forming an inner peripheral surface and a resin layer (surface layer) 15A arranged on the outer peripheral side of the elastic layer 15B to form an outer peripheral surface. It is composed.

It is preferable that the elastic layer 15B and the resin layer 15A are arranged so as to be in direct contact with each other at the interface thereof, or are arranged only via an adhesive layer (not shown) between them. That is, it is preferable that no layer other than the adhesive layer is formed between the elastic layer 15B and the resin layer 15A.

Hereinafter, each layer constituting the belt member 15 will be described.

(Elastic layer)
The elastic layer is composed of a material having elasticity (elastic material), and preferably contains a rubber material. Further, the elastic layer may contain a conductive agent from the viewpoint of imparting conductivity, and may further contain other well-known additives.

-JIS-A hardness-
The JIS-A hardness of the elastic layer is 50 ° or more and 90 ° or less. It is more preferably 60 ° or more and 80 ° or less, and further preferably 70 ° or more and 80 ° or less.

Since the JIS-A hardness of the elastic layer constituting the inner peripheral surface is 90 ° or less, good nip formation is possible at a position where the belt member is sandwiched between the two members (between the other member and the opposing member). Excellent in obedience to the rolls when they are bridged and rotationally driven in a state where tension is applied to a plurality of rolls. Then, in the image forming apparatus, the plurality of rolls are bridged in a tensioned state and are arranged so as to form a nip with other members, and the image shift occurs when the roll is used for forming an image. Is suppressed.
On the other hand, when the JIS-A hardness is 50 ° or more, the tension change due to the belt elongation when the multiple rolls are stretched and rotationally driven in a state where tension is applied is suppressed, and the drive as a belt member is suppressed. Excellent in terms of transmission.

The JIS-A hardness of the elastic layer can be adjusted by selecting the elastic material to be used.

Here, the measurement of the JIS-A hardness of the elastic layer is performed according to JIS K6253 (2012) using a durometer type A (manufactured by Teclock). Specifically, avoiding an impact, the push needle is quickly pressed against the inner peripheral surface of the elastic layer, and the maximum value of the pointer is read within 1 second. Then, this measurement is repeated 5 times, and the average value is obtained as the JIS-A hardness of the elastic layer.

-Arithmetic mean roughness Ra and maximum height Rz-
The arithmetic average roughness Ra of the inner peripheral surface of the elastic layer is preferably 2 μm or less, more preferably 1 μm or less.
When the arithmetic average roughness Ra is 2 μm or less, the frictional property (rotational driveability) with the rolls is excellent when they are bridged and rotationally driven in a state where tension is applied to the plurality of rolls. Therefore, the image shift that occurs when the plurality of rolls are stretched in the image forming apparatus and are arranged so as to form a nip with other members and used for forming an image. Is suppressed.

The maximum height Rz of the inner peripheral surface of the elastic layer is preferably 7 μm or less, more preferably 5 μm or less.
When the maximum height Rz is 7 μm or less, the frictional property (rotational driveability) with the rolls is excellent when they are bridged and rotationally driven in a state where tension is applied to the plurality of rolls. Therefore, the image shift that occurs when the plurality of rolls are stretched in the image forming apparatus and are arranged so as to form a nip with other members and used for forming an image. Is suppressed.

Here, the arithmetic mean roughness Ra and the maximum height Rz on the inner peripheral surface of the elastic layer are measured according to JIS B0601 (2001). Specifically, it is measured under the following conditions using a surface roughness meter (Surfcom 575A, manufactured by Tokyo Seimitsu Co., Ltd.).
-Measurement type: Roughness measurement-Measurement length: 4.0 mm
・ Cutoff wavelength: 0.8 mm
・ Measurement range: ± 32.0 μm
・ Measurement speed: 0.5 mm / s
-Cutoff type: 2RC (phase uncompensated)
・ Tilt correction: Least squares straight line correction

The method of controlling the arithmetic mean roughness Ra and the maximum height Rz of the inner peripheral surface of the elastic layer within the above-mentioned ranges is not particularly limited. For example, in the case where the elastic layer is formed by applying a coating liquid for forming an elastic layer to the outer peripheral surface of a cylindrical mold and performing a drying treatment (further, if necessary, a heat treatment), the gold. A method of controlling the roughness of the outer peripheral surface of the mold can be mentioned. Further, after the elastic layer is formed, the inner peripheral surface may be subjected to surface treatment such as polishing or etching.

-Elastic material-
Examples of the elastic material used for the elastic layer include urethane rubber, ethylene-propylene-diene copolymer rubber (EPDM), epichlorohydrin rubber (ECO), acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), and styrene. -Butadiene copolymer rubber (SBR), chlorinated polyisoprene rubber, isoprene rubber, acrylonitrile-butadiene rubber, hydrogenated polybutadiene rubber, butyl rubber, silicone rubber, fluororubber and other rubber materials, polyurethane, polyethylene, polyamide, polypropylene and other resins Etc., and examples thereof include a material obtained by mixing one type or two or more types of these.

Among these, urethane rubber, from the viewpoint of nip formation in a state where the belt member is sandwiched between the two members (between the other member and the opposing member) and responsiveness to the roll over which the belt member is hung. A material obtained by mixing ethylene-propylene-diene copolymer rubber (EPDM), epichlorohydrin rubber (ECO), chloroprene rubber (CR) and ethylene-propylene-diene copolymer rubber (EPDM) is more preferable, and excellent flame retardancy. A material obtained by mixing chloroprene rubber (CR) and ethylene-propylene-diene copolymer rubber (EPDM) is more preferable in that a chloroprene rubber (CR) and an ethylene-propylene-diene copolymer rubber (EPDM) can be obtained.

-Conducting agent-
The elastic layer may contain a conductive agent from the viewpoint of imparting conductivity.
The conductive agent is conductive (for example, volume resistivity ^{less than 10 7} Ω · cm, the same applies hereinafter) or semi-conductive (for example, volume resistivity 10 ⁷ Ω · cm or more and 10 ¹³ Ω · cm or less, and the same applies hereinafter). ) Powder (preferably a powder composed of particles having a primary particle size of less than 10 μm, preferably a powder composed of particles having a primary particle size of 1 μm or less).

The conductive agent is not particularly limited, but for example, carbon black (for example, Ketjen black, acetylene black, carbon black whose surface has been oxidized), carbon fiber, carbon nanotube, carbon-based substance such as graphite, metal, or Alloys (eg aluminum, nickel, copper, silver, etc.), metal oxides (eg, yttrium oxide, tin oxide, indium oxide, antimony oxide, SnO _{2-In 2} O ₃ composite oxides, etc.), ionic conductive materials (eg titanium) Potassium acid acid, LiCl, etc.) and the like.

The conductive agent is selected according to the purpose of use, but carbon black is preferable, and pH 5 or less (preferably pH 4) is particularly good from the viewpoint of stability of electric resistance over time and electric field dependence that suppresses electric field concentration due to transfer voltage. An oxidation-treated carbon black having a pH of 5.5 or less, more preferably 4.0 or less (for example, carbon black obtained by imparting a carboxyl group, a quinone group, a lactone group, a hydroxyl group or the like to the surface) is preferable.

The average primary particle size of carbon black is, for example, preferably 10 nm or more and 50 nm or less, and more preferably 15 nm or more and 30 nm or less.
The average primary particle size of carbon black is measured by the following method.
First, the belt member to be measured is cut by a microtome, a measurement sample having a thickness of 100 nm is collected, and this measurement sample is observed by a TEM (transmission electron microscope). Then, the diameter of a circle equal to the projected area of each of the 50 carbon black particles is defined as the particle diameter, and the average value thereof is defined as the average primary particle diameter.

The content of the conductive agent in the elastic layer is selected according to the desired resistance. For example, it is preferably 20% by mass or more and 35% by mass or less, and further 25% by mass or more and 30% by mass with respect to the total mass of the elastic layer. % Or less is more preferable.
The conductive agent may be used alone or in combination of two or more.

-Other additives-
Other additives other than the conductive agent include, for example, a dispersant for improving the dispersibility of the conductive agent (carbon black, etc.), various fillers for imparting various functions such as mechanical strength, a catalyst, and a film forming. Leveling agent for improving quality, releasable material for improving releasability (for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexa) Fluororesin particles such as fluoropropylene copolymer (FEP)) and the like.

-Thickness-
The average thickness of the elastic layer is preferably 300 μm or more and 600 μm or less, and more preferably 400 μm or more and 500 μm or less.
When the average thickness of the elastic layer is 300 μm or more, good nip formation is excellent at a position where the belt member is sandwiched between the two members (between the other member and the opposing member), and the elastic layer can be formed into a plurality of rolls. It is excellent in followability with the roll when it is bridged and rotationally driven in a state where tension is applied. Then, in the image forming apparatus, the plurality of rolls are bridged in a tensioned state and are arranged so as to form a nip with other members, and the image shift occurs when the roll is used for forming an image. Is suppressed.
On the other hand, when the average thickness is 600 μm or less, it is excellent in that stable transfer can be performed without applying an excessive voltage in forming a transfer electric field in the transfer portion for transferring toner or the like.

Here, the thickness of each layer constituting the belt member can be measured by using an eddy current type film thickness meter CTR-1500E manufactured by Sanko Electronics Co., Ltd. In this embodiment, measurements were taken at 12 points (3 points at equal intervals in the axial direction of the belt x 4 points at equal intervals in the weekly direction of the belt), and the average value was taken as the average thickness.

Here, the belt axial direction refers to a direction that becomes the axial direction of the rolls when the belt member is hung on the plurality of rolls in a state where tension is applied.

(Adhesive layer)
In the belt member according to the present embodiment, an elastic layer and a resin layer may be formed via an adhesive layer. The adhesive used for the adhesive layer is not particularly limited, and known adhesives are used, and examples thereof include a silane coupling agent, a silicone-based adhesive, and a urethane-based adhesive.

(Resin layer)
The resin layer may be composed of a resin material, may contain a conductive agent from the viewpoint of imparting conductivity, and may be further composed of other well-known additives.

− Elastic modulus −
The elastic modulus of the resin layer is 2000 MPa or more and 6000 MPa or less. More preferably, it is 3000 MPa or more and 6000 MPa or less.

When the elastic modulus of the resin layer constituting the outer peripheral surface is 2000 MPa or more, the outer peripheral surface has rigidity and is hard to be deformed, and temporary and local speed fluctuation of the belt member driven to rotate is suppressed. .. Then, in the image forming apparatus, the plurality of rolls are bridged in a tensioned state and are arranged so as to form a nip with other members, and the image shift occurs when the roll is used for forming an image. Is suppressed.
On the other hand, when the elastic modulus is 6000 MPa or less, it is promoted by the load due to the rotational operation when the multiple rolls are stretched and repeatedly rotationally driven in a state where tension is applied, and the stress concentration on the end portion in the axial direction of the belt. It is excellent in durability against fatigue fracture.

The elastic modulus of the resin layer can be adjusted by selecting the resin material to be used and adjusting the thickness of the resin layer.

Here, the elastic modulus in the resin layer is measured as follows.
A sheet having a belt member width of 2 mm is cut out and the elastic layer is peeled off to prepare a measurement sample. This measurement sample is measured for elastic modulus at 25 ° C. using a dynamic viscoelasticity test device (DDV-01FP manufactured by A & D Co., Ltd.) in accordance with JIS K7244-4.

-Resin material The resin material used for the resin layer is preferably the main component of the resin layer. For example, the content of the resin material in the resin layer is preferably 18% by mass or more and 30% by mass or less with respect to the total mass of the resin layer.

Examples of the resin material used for the resin layer include polyimide resin, fluoride polyimide resin, polyamide resin, polyamideimide resin, polyether ether ester resin, polyarylate resin, and polyester resin. For each resin layer, one type of resin material may be used alone, or two or more types may be used in combination.

Among these, it is more preferable to use at least one of the polyimide resin and the polyamide-imide resin from the viewpoint of increasing the rigidity of the outer peripheral surface and obtaining the difficulty of deformation when a plurality of rolls are stretched and stretched. preferable.
Further, by using at least one of the polyimide resin and the polyamide-imide resin, wear and deterioration of the resin layer constituting the outermost surface are suppressed to obtain high resistance, and cleaning for cleaning the outer peripheral surface of the belt member is performed. Excellent cleanability can be obtained even in the aspect of providing the device.

-Polyimide resin-
Examples of the polyimide resin include imidized polyamic acids (polyamic acids), which are polymers of tetracarboxylic dianhydride and diamine compounds. Specifically, the polyimide resin is obtained by polymerizing an equimolar amount of a tetracarboxylic acid dianhydride and a diamine compound in a solvent to obtain a polyamic acid solution, and imidizing the polyamic acid. Can be mentioned.

Examples of the polyimide resin include resins having a structural unit represented by the following general formula (I).

(In the general formula (I), R ¹ is a tetravalent organic group, which is an aromatic group, an aliphatic group, a cyclic aliphatic group, a group combining an aromatic group and an aliphatic group, or a group in which they are substituted. A group (eg, a residue of tetracarboxylic acid dianhydride described below). R ² is a divalent organic group, aromatic group, aliphatic group, cyclic aliphatic group, aromatic group and fat. A group in which a group group is combined or a group in which they are substituted (for example, a residue of a diamine compound described later can be mentioned).

Specifically, as the tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic Acid dianhydride, 2,3,3',4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Dihydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) sulfonic acid dianhydride, perylene-3,4,9,10 Examples thereof include −tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, and ethylenetetracarboxylic dianhydride.

On the other hand, specific examples of the diamine compound include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, and 4,4'-diaminodiphenylsulfide. , 3,3'-diaminodiphenylsulphon, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl 4,4'-biphenyldiamine, benzidine, 3,3'-dimethylbenzidine , 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenylsulphon, 4,4'-diaminodiphenylpropane, 2,4-bis (β-aminotri-butyl) toluene, bis (p-β-amino-) Tertiary butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bis-p- (1,1-dimethyl-5-amino-pentyl) benzene, 1-isopropyl-2,4-m -Phenylenediamine, m-xylylene diamine, p-xylylene diamine, di (p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-Methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminoprovoxyetan, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine , 2,5-Dimethylheptamethylenediamine, 3-Methylheptamethylenediamine, 5-Methylnonamethylenediamine, 2,17-diaminoeicosadecan, 1,4-diaminocyclohexane, 1,10-diamino-1,10- dimethyl decane, 12-diamino-octadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, _{piperazine, H 2 N (CH 2)} 3 O (CH 2) 2 O (CH 2) NH 2, Examples thereof include _{H 2} N (CH ₂ ) ₃ S (CH ₂ ) ₃ NH ₂ , H ₂ N (CH ₂ ) ₃ N (CH ₃ ) ₂ (CH ₂ ) ₃ NH _2.

As the solvent for polymerizing the tetracarboxylic dianhydride and the diamine, a polar solvent (organic polar solvent) is preferably used from the viewpoint of solubility and the like. As the polar solvent, N, N-dialkylamides are preferable, and specifically, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide having a low molecular weight thereof are preferable. , N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, tetramethylenesulfone, dimethyltetramethylenesulfone and the like. These may be singular or used in combination.

-Polyamide-imide resin-
Examples of the polyamide-imide resin include a polyamide-imide resin obtained by dehydrating and ring-closing a polyamide-polyamic acid resin which is a condensate of a tricarboxylic acid and a diamine compound.
Specifically, as the polyamide-imide resin,
(1) Method of subjecting an equimolar amount of tricarboxylic acid anhydride and diamine to polycondensation and imidization reaction (dehydration ring closure reaction) at high temperature in the presence of a dehydration catalyst in an organic polar solvent (2) With tricarboxylic acid anhydride monochloroide Method of polycondensing and imidizing an equimolar amount of diamine in an organic polar solvent at a low temperature (3) Method of polycondensing and imidizing a tricarboxylic acid anhydride and diisocyanate in an organic polar solvent at a high temperature, etc. Examples thereof include the polyamide imide resin obtained by.
The coating liquid contains a polyamide-polyamic acid resin before the imidization reaction, which is a precursor of the polyimide resin, and after coating, the polyamide-polyamic acid resin is imidized to form a polyamide-imide resin.

Examples of the tricarboxylic acid anhydride include trimellitic acid anhydride and trimellitic acid monoclonal anhydride.

Examples of the diamine compound include diamine compounds used for the synthesis of polyamic acids, and aromatic diamine compounds are particularly preferable.
Examples of the aromatic diamine compound include 3,3'-diaminobenzophenylone, P-phenylenediamine, 4,4'-diaminodiphenyl, 4,4'-diaminodiphenylamide, and 4,4'-diamino. Diphenylmethane, 4,4'-diaminodiphenyl ether, bis [4- {3- (4-aminophenoxy) benzoyl} phenyl] ether, 4,4'-bis (3-aminophenoxy) biphenyl, bis [4- ( Examples thereof include 3-aminophenoxy) phenyl] sulfone 2,2'-bis [4- (3-aminophenoxy) phenyl] propane and the like.

Examples of the diisocyanate compound include those in which two amino groups in the diamine compound used for the synthesis of polyamic acid are substituted with isocyanate groups, and aromatic diisocyanate compounds are particularly preferable.
Examples of the diisocyanate compound include 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3, 3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxy Examples thereof include biphenyl-4,4'-diisocyanate and 2,2'-dimethoxybiphenyl-4,4'-diisocyanate.
Examples of the diisocyanate compound include those in which the isocyanato group is stabilized with a blocking agent. Examples of the blocking agent include alcohol, phenol, oxime, etc., but there are no particular restrictions.

-Conducting agents and other additives-
Further, a conductive agent and other additives other than the conductive agent may be added to the resin layer. Examples of the conductive agent and other additives include the conductive agent and other additives described in the section of the elastic layer.

The content of the conductive agent in the resin layer is selected according to the target resistance. For example, it is preferably 1% by mass or more and 50% by mass or less, and further 2% by mass or more and 40% by mass or less, based on the total mass of the resin layer. The following is more preferable, and 4% by mass or more and 30% by mass or less is further preferable.
The conductive agent may be used alone or in combination of two or more.

-Thickness-
The average thickness of the resin layer is preferably 50 μm or more and 70 μm or less, more preferably 50 μm or more and 65 μm or less, and further preferably 50 μm or more and 60 μm or less.
When the average thickness of the resin layer is 50 μm or more, the rigidity on the outer peripheral surface is further increased and it is easy to obtain the difficulty of deformation, and the temporary and local speed fluctuation of the rotationally driven belt member is further suppressed. Easy to do. Then, in the image forming apparatus, the plurality of rolls are bridged in a tensioned state and are arranged so as to form a nip with other members, and the image shift occurs when the roll is used for forming an image. Is likely to be suppressed.
On the other hand, when the average thickness is 70 μm or less, the charge inflow in the circumferential direction is suppressed in the electric field formation in the transfer portion where the toner or the like is transferred, and it is excellent in that a more uniform and stable transfer performance can be obtained.

(Manufacturing method of belt member)
Here, a method of manufacturing the belt member according to the present embodiment will be described. The method for manufacturing the belt member is not particularly limited, and examples thereof include a manufacturing method having the following steps.

・ (Preparation process for coating liquid for forming resin layer)
A coating liquid for forming a resin layer, that is, a coating liquid for forming a resin layer in which the above-mentioned resin material, conductive agent, or the like is dissolved or dispersed in a solvent is prepared.
・ (Elastic layer forming process)
Additives such as conductive agents (electromagnetic conductive agents, ionic conductive agents, etc.) are mixed and dispersed in the above-mentioned elastic materials (CR, NBR, EPDM, ECO, etc.) as necessary, and then kneaded with a pressure kneader or the like. It is kneaded with a machine and then extruded by adding a vulcanizing agent, a vulcanization accelerator and the like. When the kneaded elastic material is extruded, a metal cylinder called a vulcanized mandrel having an outer diameter of the same size as the inner diameter of the belt is covered with the kneaded elastic material under predetermined conditions (for example). A method of vulcanizing at 170 ° C. for 1 hour) can be mentioned.
・ (Resin layer forming process)
A coating liquid for forming a resin layer is applied onto the elastic layer of the cylinder on which the elastic layer is formed. A known method can be applied as the coating method. The cylinder coated with the coating liquid is dried (further heated if necessary) while rotating to solidify the resin layer.
・ (Demolding process)
Then, the solidified belt member is removed from the cylinder (demolding) to obtain the belt member.
Further, the outer peripheral surface and the inner peripheral surface of the belt member may be subjected to surface treatment such as polishing and etching. In addition, the obtained belt member may be further subjected to drilling, ribbing, or the like.
Further, before forming the resin layer, an adhesive may be applied on the elastic layer to form the adhesive layer.

In the above method, the belt member was obtained by laminating the elastic layer and the resin layer on the outer peripheral surface of the cylinder in this order, but conversely, the resin layer and the elastic layer were laminated on the inner peripheral surface side of the cylindrical mold in the order of the elastic layer and the elastic layer. Belt members may be obtained by laminating.

(Characteristics of belt member)
The surface resistivity of the outer peripheral surface of the belt member according to the present embodiment is, for example, 9 (common logarithmic value) from the viewpoint of transferability when used as an intermediate transfer belt, a recording medium transport belt, or the like in an image forming apparatus. It is preferably LogΩ / □ or more and 13 (LogΩ / □) or less, and more preferably 10 (LogΩ / □) or more and 12 (LogΩ / □) or less.
The common logarithmic value of the surface resistivity is controlled by the type of the conductive agent and the amount of the conductive agent added.

Here, the method for measuring the surface resistivity is as follows. Measurement is performed according to JIS-K6911 using a circular electrode (for example, "UR probe" of Hi-Lester IP manufactured by Mitsubishi Yuka Co., Ltd.). The method of measuring the surface resistivity will be described with reference to the drawings. FIG. 3 is a schematic plan view (A) and a schematic cross-sectional view (B) showing an example of a circular electrode. The circular electrode shown in FIG. 3 includes a first voltage application electrode A and a plate-shaped insulator B. The first voltage application electrode A has a columnar electrode portion C and an inner diameter larger than the outer diameter of the columnar electrode portion C, and is a cylindrical ring-shaped electrode that surrounds the columnar electrode portion C at regular intervals. It includes a part D. A belt T is sandwiched between the columnar electrode portion C and the ring-shaped electrode portion D of the first voltage application electrode A and the plate-shaped insulator B, and the columnar electrode portion C and the ring-shaped electrode of the first voltage application electrode A are sandwiched between them. The current I (A) that flows when the voltage V (V) is applied to the part D is measured, and the surface resistance ρs (Ω / □) of the transfer surface of the belt T is calculated by the following formula. Here, in the following formula, d (mm) indicates the outer diameter of the columnar electrode portion C, and D (mm) indicates the inner diameter of the ring-shaped electrode portion D.
Formula: ρs = π × (D + d) / (D−d) × (V / I)
For the surface resistance, a circular electrode (UR probe of Hi-Lester IP manufactured by Mitsubishi Yuka Co., Ltd .: outer diameter Φ16 mm of columnar electrode portion C, inner diameter Φ30 mm, outer diameter Φ40 mm of ring-shaped electrode portion D) was used. The current value after applying a voltage of 500 V for 10 seconds under a 22 ° C./55% RH environment is obtained and calculated.

The total volume resistivity of the belt member according to the present embodiment is, for example, 8 (LogΩcm) as a common logarithmic value from the viewpoint of transferability when used as an intermediate transfer belt, a recording medium transfer belt, or the like in an image forming apparatus. ) Or more and preferably 13 (LogΩcm) or less. The common logarithmic value of volume resistivity is controlled by the type of conductive agent and the amount of conductive agent added.

Here, the volume resistivity is measured according to JIS-K6911 using a circular electrode (for example, a UR probe of Hi-Lester IP manufactured by Mitsubishi Yuka Co., Ltd.). The method for measuring the volume resistivity will be described with reference to FIG. The measurement is performed with the same device as the surface resistivity. However, in the circular electrode shown in FIG. 3, a second voltage application electrode B'is provided instead of the plate-shaped insulator B at the time of measuring the surface resistivity. Then, the belt T is sandwiched between the columnar electrode portion C and the ring-shaped electrode portion D of the first voltage application electrode A and the second voltage application electrode B', and the columnar electrode portion C of the first voltage application electrode A is sandwiched between them. The current I (A) flowing when the voltage V (V) is applied between the second voltage application electrode B and the second voltage application electrode B is measured, and the volume resistance ρv (Ωcm) of the belt T is calculated by the following formula. Here, in the following formula, t indicates the thickness of the belt T.
Equation ρv = 19.6 × (V / I) × t
For the volume resistance, a circular electrode (UR probe of Hi-Lester IP manufactured by Mitsubishi Yuka Co., Ltd .: outer diameter Φ16 mm of columnar electrode portion C, inner diameter Φ30 mm, outer diameter Φ40 mm of ring-shaped electrode portion D) was used. The current value after applying a voltage of 500 V for 10 seconds under a 22 ° C./55% RH environment is obtained and calculated.

Further, the numerical value of 19.6 shown in the above formula is an electrode coefficient for converting into resistivity, and is πd ^{2 from the outer diameter d (mm) of the columnar electrode portion and the sample thickness t (cm).} Calculated as / 4t. The thickness of the belt T is measured using an eddy current film thickness meter CTR-1500E manufactured by Sanko Electronics Co., Ltd.

The thickness of the belt member according to the present embodiment is, for example, preferably 0.05 mm or more and 0.5 mm or less in total thickness (average thickness), more preferably 0.06 mm or more and 0.30 mm or less, and further preferably 0. It is 0.6 mm or more and 0.15 mm or less.

(Use)
The belt member according to the present embodiment is a belt member in an image forming apparatus, for example, an intermediate transfer belt in which a toner image on an image holder is transferred (primary transfer) and then transferred again on a recording medium (secondary transfer). When the toner image held on the transfer body is secondarily transferred to a recording medium, the secondary transfer belt is brought into contact with the back surface (non-transfer surface) of the recording medium to convey the recording medium and apply a voltage for the secondary transfer. It is used as a recording medium transport belt for transporting a recording medium and applying a voltage for transfer in a mode in which a toner image on an image holder is directly transferred to the surface of the recording medium.

<Image forming device>
The image forming apparatus according to the present embodiment includes an image holder, a charging means for charging the image holder, a static charge image forming means for forming a static charge image on the surface of the charged image holder, and toner. A developing means for accommodating a static charge image developer containing the mixture and developing the static charge image formed on the surface of the image holder as a toner image by the static charge image developer, and a developing means formed on the surface of the image holder. A transfer means for transferring a toner image to the surface of a recording medium is provided.
The transfer means includes a belt member unit including the belt member according to the present embodiment and a plurality of rolls for hanging the belt member under tension.

For example, in the embodiment in which the belt member according to the present embodiment is provided as an intermediate transfer belt, an image holder, a charging means for charging the image holder, and a static charge image are formed on the surface of the charged image holder. A static charge image forming means to be formed, a developing means for developing a static charge image formed on the surface of the image holder as a toner image by a static charge image developer containing toner, and a surface of the image holder are formed. An intermediate transfer belt (belt member according to the present embodiment) on which the transferred toner image is transferred, and a primary transfer means for primary transfer of the toner image formed on the surface of the image holder to the surface of the intermediate transfer belt. Image forming including a secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer belt to a recording medium, and a fixing means for fixing the toner image transferred to the recording medium. Equipment is mentioned. Further, a cleaning device may be provided in which a cleaning member (for example, a cleaning blade) is brought into contact with the intermediate transfer belt to clean the outer peripheral surface of the intermediate transfer belt.

The image forming apparatus according to the present embodiment is, for example, a normal monocolor image forming apparatus in which only a single color toner is stored in a developing apparatus, and a toner image held on an image holder is sequentially subjected to primary transfer to an intermediate transfer body. Examples thereof include a repeating color image forming apparatus and a tandem type color image forming apparatus in which a plurality of image holders equipped with a developer for each color are arranged in series on an intermediate transfer body.

Hereinafter, the image forming apparatus according to the present embodiment will be described with reference to the drawings.

-Configuration of image forming apparatus (first aspect)
FIG. 4 is a schematic configuration diagram showing a configuration of an example of an image forming apparatus according to the present embodiment.

As shown in FIG. 4, the image forming apparatus 100 according to the present embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of toner images of each color component are formed by an electrophotographic method. Image forming units 1Y, 1M, 1C, 1K, and a primary transfer unit 10 for sequentially transferring (primary transfer) each color component toner image formed by each image forming unit 1Y, 1M, 1C, 1K to an intermediate transfer belt 15. , A secondary transfer unit 20 that collectively transfers (secondary transfer) the superimposed toner image transferred on the intermediate transfer belt 15 to paper K, which is a recording medium, and fixing that fixes the secondary transferred image on paper K. The device 60 and the like are provided. Further, the image forming apparatus 100 has a control unit 40 that controls the operation of each device (each unit).

The intermediate transfer belt 15 is the belt member according to the present embodiment described above.

Each image forming unit 1Y, 1M, 1C, 1K of the image forming apparatus 100 includes a photoconductor 11 that rotates in the direction of arrow A as an example of an image holder that holds a toner image formed on the surface.

A charger 12 for charging the photoconductor 11 is provided around the photoconductor 11 as an example of the charging means, and a laser exposure device for writing an electrostatic latent image on the photoconductor 11 as an example of the latent image forming means. 13 (the exposure beam in the figure is indicated by the reference numeral Bm) is provided.

Further, around the photoconductor 11, as an example of the developing means, a developer 14 in which each color component toner is accommodated and the electrostatic latent image on the photoconductor 11 is visualized by the toner is provided, and the photoconductor 11 is provided. A primary transfer roll 16 for transferring each color component toner image formed above to the intermediate transfer belt 15 by the primary transfer unit 10 is provided.

Further, a photoconductor cleaner 17 for removing residual toner on the photoconductor 11 is provided around the photoconductor 11, and a charger 12, a laser exposure device 13, a developing device 14, a primary transfer roll 16, and a photoconductor cleaner are provided. 17 electrophotographic devices are sequentially arranged along the rotation direction of the photoconductor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been done.

The intermediate transfer belt 15 is circulated (rotated) by various rolls in the B direction shown in FIG. 4 at a speed suitable for the purpose. These various rolls include a drive roll 31 that is driven by a motor (not shown) to rotate the intermediate transfer belt 15, and a support roll 32 that supports the intermediate transfer belt 15 extending substantially linearly along the arrangement direction of each photoconductor 11. , A tension applying roll 33 that applies tension to the intermediate transfer belt 15 and functions as a correction roll that suppresses the meandering of the intermediate transfer belt 15, a back roll 25 provided in the secondary transfer portion 20, and a residue on the intermediate transfer belt 15. It has a cleaning back roll 34 provided in a cleaning section for scraping toner.

The primary transfer unit 10 is composed of a primary transfer roll 16 as an opposing member arranged so as to face the photoconductor 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 is composed of a core body and a sponge layer as an elastic layer fixed around the core body. The core body is a cylindrical rod made of a metal such as iron or SUS. The sponge layer is formed of a blended rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black, and is a sponge-like cylindrical roll having ^{a volume resistivity of 10 7.5} Ωcm or more and 10 ^{8.5 Ω cm or less.}

Then, the primary transfer roll 16 is pressure-welded to the photoconductor 11 with the intermediate transfer belt 15 interposed therebetween, and the primary transfer roll 16 has a voltage (primary) opposite to that of the toner charging polarity (minus polarity; the same applies hereinafter). Transfer bias) is applied. As a result, the toner images on the respective photoconductors 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, and the superimposed toner images are formed on the intermediate transfer belt 15.

The secondary transfer unit 20 includes a back surface roll 25 and a secondary transfer roll 22 arranged on the toner image holding surface side of the intermediate transfer belt 15.

The back roll 25 is composed of a tube of EPDM and NBR blended rubber whose surface is dispersed with carbon, and EPDM rubber inside. Then, the surface resistivity is ^{formed to be 10 7} Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Polymer Instruments Co., Ltd., the same applies hereinafter). To. The back surface roll 25 is arranged on the back surface side of the intermediate transfer belt 15 to form a counter electrode of the secondary transfer roll 22, and a metal feeding roll 26 to which the secondary transfer bias is stably applied is contact-arranged. ing.

On the other hand, the secondary transfer roll 22 is composed of a core body and a sponge layer as an elastic layer fixed around the core body. The core body is a cylindrical rod made of a metal such as iron or SUS. The sponge layer is formed of a blended rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black, and is a sponge-like cylindrical roll having ^{a volume resistivity of 10 7.5} Ωcm or more and 10 ^{8.5 Ω cm or less.}

Then, the secondary transfer roll 22 is pressure-welded to the back surface roll 25 with the intermediate transfer belt 15 interposed therebetween, and the secondary transfer roll 22 is grounded to form a secondary transfer bias with the back surface roll 25. The toner image is secondarily transferred onto the paper K conveyed to the transfer unit 20.

Further, on the downstream side of the secondary transfer portion 20 of the intermediate transfer belt 15, an intermediate transfer belt that cleans the surface of the intermediate transfer belt 15 by removing residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer. A cleaner 35 is provided so as to be detachable.

The intermediate transfer belt 15, the primary transfer unit 10 (primary transfer roll 16), and the secondary transfer unit 20 (secondary transfer roll 22) correspond to an example of the transfer means.

On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 that generates a reference signal as a reference for taking the image forming timing in each image forming unit 1Y, 1M, 1C, 1K is provided. It is arranged. Further, an image density sensor 43 for adjusting the image quality is arranged on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes the mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. According to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C, 1K are configured to initiate image formation.

Further, in the image forming apparatus according to the present embodiment, as a transporting means for transporting the paper K, the paper accommodating unit 50 accommodating the paper K and the paper K accumulated in the paper accommodating unit 50 are taken out at a predetermined timing. The paper feed roll 51 that conveys the paper K, the transfer roll 52 that conveys the paper K fed by the paper feed roll 51, the transfer guide 53 that feeds the paper K conveyed by the transfer roll 52 to the secondary transfer unit 20, and the secondary transfer. It includes a transport belt 55 that transports the paper K that is secondarily transferred by the roll 22 to the fixing device 60, and a fixing inlet guide 56 that guides the paper K to the fixing device 60.

Next, the basic image forming process of the image forming apparatus according to the present embodiment will be described.
In the image forming apparatus according to the present embodiment, the image data output from an image reading device (not shown), a personal computer (PC) (not shown), or the like is subjected to image processing by an image processing device (not shown), and then the image forming unit 1Y. , 1M, 1C, 1K perform the image drawing work.

The image processing device performs image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame erasing and color editing, and various image editing such as movement editing on the input reflectance data. Will be done. The image data that has undergone image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure device 13.

In the laser exposure device 13, for example, the exposure beam Bm emitted from the semiconductor laser is irradiated to each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. .. In each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K, after the surface is charged by the charger 12, the surface is scanned and exposed by the laser exposure device 13, and an electrostatic latent image is formed. The formed electrostatic latent image is developed as a toner image of each color of Y, M, C, and K by each of the image forming units 1Y, 1M, 1C, and 1K.

The toner image formed on the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K is transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 in which each photoconductor 11 and the intermediate transfer belt 15 come into contact with each other. Toner. More specifically, in the primary transfer unit 10, the primary transfer roll 16 applies a voltage (primary transfer bias) opposite to the charging polarity (minus polarity) of the toner to the base material of the intermediate transfer belt 15, and the toner image. Is sequentially superposed on the surface of the intermediate transfer belt 15 to perform the primary transfer.

After the toner image is sequentially primary-transferred to the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is conveyed to the secondary transfer unit 20, the transfer means rotates the paper feed roll 51 in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 20, and the target is from the paper storage unit 50. Paper K of size is supplied. The paper K supplied by the paper feed roll 51 is conveyed by the transfer roll 52 and reaches the secondary transfer unit 20 via the transfer guide 53. Before reaching the secondary transfer unit 20, the paper K is temporarily stopped, and the alignment roll (not shown) rotates according to the movement timing of the intermediate transfer belt 15 on which the toner image is held, so that the paper K is formed. Is aligned with the position of the toner image.

In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the paper K conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At that time, when a voltage (secondary transfer bias) having the same polarity as the charging polarity (minus polarity) of the toner is applied from the power feeding roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back surface roll 25. Will be done. Then, the unfixed toner image held on the intermediate transfer belt 15 is electrostatically transferred onto the paper K collectively in the secondary transfer unit 20 pressurized by the secondary transfer roll 22 and the back surface roll 25. Toner.

After that, the paper K on which the toner image is electrostatically transferred is conveyed as it is in a state of being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is provided on the downstream side of the secondary transfer roll 22 in the paper transfer direction. It is transported to the belt 55. The transport belt 55 transports the paper K to the fixing device 60 according to the optimum transport speed of the fixing device 60. The unfixed toner image on the paper K conveyed to the fixing device 60 is fixed on the paper K by being subjected to a fixing process by heat and pressure by the fixing device 60. Then, the paper K on which the fixed image is formed is conveyed to a paper ejection accommodating portion (not shown) provided in the ejection unit of the image forming apparatus.

On the other hand, after the transfer to the paper K is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning section as the intermediate transfer belt 15 rotates, and is conveyed by the cleaning back roll 34 and the intermediate transfer belt cleaner 35. It is removed from the intermediate transfer belt 15.

Although the present embodiment has been described above, the present embodiment is not limited to the above embodiment, and various modifications, changes, and improvements can be made.

Offset of the primary transfer roll 16 In the image forming apparatus 100 shown in FIG. 4, the image holder 11 is arranged directly above the primary transfer roll 16, that is, the axis of the primary transfer roll 16 and the axis of the image holder 11. An aspect is shown in which the straight lines connecting the two are arranged in a positional relationship in which the straight lines connecting the two are orthogonal to the driving direction of the intermediate transfer belt 15. However, the position where the primary transfer roll 16 is arranged is not limited to this, and may be shifted (offset) in the driving direction of the intermediate transfer belt 15, for example.
Specifically, as shown in FIG. 5, the image holder 11 and the intermediate transfer belt are offset to the drive direction side of the intermediate transfer belt 15 so as to have a distance L1 with respect to the position of the axial center of the image holder 11. It may be arranged so as to form a nip portion having a width of 15 and the distance L2.
By offsetting the position of the primary transfer roll 16 with respect to the image holder 11, the sandwiching of the intermediate transfer belt 15 is relaxed or not sandwiched, so that the image shift that occurs when used for image formation Is more likely to be suppressed.

-Structure of image forming apparatus (second aspect)
Next, an image forming apparatus using the belt member according to the present embodiment as a recording medium transport belt will be described as an example.
FIG. 6 is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.

In the image forming apparatus 200 shown in FIG. 6, the units Y, M, C, and BK are provided with the photoconductor drums (image holders) 201Y, 201M, 201C, and 201BK, respectively, so as to rotate in the meter direction at the time of arrow C. Be done. Around the photoconductor drums 201Y, 201M, 201C, 201BK, there are chargers (charging means) 202Y, 202M, 202C, 202BK, and exposure devices (static charge image forming means) 214Y, 214M, 214C, 214BK, and each color development. The apparatus (development means / yellow developing apparatus 203Y, magenta developing apparatus 203M, cyan developing apparatus 203C, black developing apparatus 203BK) and the photoconductor drum cleaning member (image holder cleaning apparatus) 204Y, 204M, 204C, 204BK are arranged, respectively. Has been done.

Four units Y, M, C, and BK are arranged in parallel with the paper transport belt (belt member) 207 in the order of units BK, C, M, and Y, but units BK, Y, C, and M are arranged in this order. An appropriate order is set according to the image forming method, such as the order of.

The paper transport belt 207 is supported from the inner surface side by four belt support rolls 206 to form an intermediate transfer belt unit. The paper transport belt 207 rotates in the counterclockwise direction of arrow A at the same peripheral speed as the photoconductor drums 201Y, 201M, 201C, and 201BK, and a part of the paper transport belt 207 located between the belt support rolls 206 is photosensitive. They are arranged so as to be in contact with the body drums 201Y, 201M, 201C, and 201BK, respectively.

The cleaning blade 212 of the paper transport belt 207 is arranged so as to come into contact with the surface (outer peripheral surface) on the paper transport side. Further, a cleaning facing roll 213 as a conductive facing member is arranged in contact with the surface on the opposite side of the cleaning blade 212 via the paper transport belt 207 to form a paper transport belt cleaning device 220. There is.

In addition to the cleaning blade 212, the paper transport belt cleaning device 220 may be further provided with brush cleaning, roll cleaning, scraper cleaning, and the like.
Further, as the cleaning facing roll 213, the one having the same configuration as the cleaning facing roll 113 used in the image forming apparatus 100 shown in FIG. 3 described above can be applied as it is.

The transfer rolls (transfer means) 205Y, 205M, 205C, 205BK are located inside the paper transport belt 207 and face the portions where the paper transport belt 207 and the photoconductor drums 201Y, 201M, 201C, 201BK are in contact with each other. The photoconductor drums 201Y, 201M, 201C, and 201BK form a transfer region for transferring the toner image to the paper (recording medium) 215 via the paper transport belt 207. As shown in FIG. 6, even if the transfer rolls 205Y, 205M, 205C, and 205BK are arranged directly under the photoconductor drums 201Y, 201M, 201C, and 201BK, they are offset from the position directly below (that is, the embodiment shown in FIG. 5 above). It may be arranged at an offset position as in).

The fixing device (fixing means) 210 is arranged so as to be transported after passing through the respective transfer regions of the paper transport belt 207 and the photoconductor drums 201Y, 201M, 201C, and 201BK.

The paper transport roll 208 transports the paper 215 to the paper transport belt 207.

In the image forming apparatus shown in FIG. 6, in the unit BK, the photoconductor drum 201BK is rotationally driven. In conjunction with this, the charger 202BK is driven to charge the surface of the photoconductor drum 201BK to the desired polarity and potential. The photoconductor drum 201BK whose surface is charged is then exposed to an image by the exposure device 214BK, and an electrostatic latent image is formed on the surface thereof.

Subsequently, the electrostatic latent image is developed by the black developing apparatus 203BK. Then, a toner image is formed on the surface of the photoconductor drum 201BK. The developer at this time may be a one-component type or a two-component type.

This toner image passes through the transfer region between the photoconductor drum 201BK and the paper transport belt 207, and the paper 215 is electrostatically attracted to the paper transport belt 207 and transported to the transfer region, and is applied from the transfer roll 205BK. By the electric field formed by the transfer bias, the paper is sequentially transferred to the surface of the paper 215.

After that, the toner remaining on the photoconductor drum 201BK is cleaned and removed by the photoconductor drum cleaning member 204BK. Then, the photoconductor drum 201BK is used for the next image transfer.

The above image transfer is also performed in units C, M and Y by the above method.

The paper 215 on which the toner image is transferred by the transfer rolls 205BK, 205C, 205M and 205Y is further conveyed to the fixing device 210 and fixed.

Residual toner is removed from the photoconductor drums 201Y, 201M, 201C, and 201BK after transfer by the photoconductor drum cleaning members 204Y, 204M, 204C, and 204BK. On the other hand, in the paper transport belt 207 after transporting the recording medium 215, residual toner is removed by the cleaning blade 212 in the paper transport belt cleaning device 220 to prepare for the next image forming process.
As described above, an image is formed on the paper.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples. In the following, "part" and "%" are based on mass unless otherwise specified.

[Example 1]
-Preparation of coating liquid for forming a resin layer A coating liquid (A1) for forming a resin layer containing a polyamide-imide resin (PAI) was prepared as follows. Carbon black (trade name: Special Black 4, manufactured by Dexahurs) is added to a polyamide-imide solution (manufactured by Hitachi Kasei Co., Ltd., HPC-9000, solvent: N-methylpyrrolidone) having a viscosity at 25 ° C. of 30 Pa · s. The mixture was mixed at a ratio of 30.5%, then dispersed by a counter-collision type disperser, and 5000 ppm of a surfactant (trade name: LS009, manufactured by Kusumoto Kasei Co., Ltd.) was added thereto to obtain a resin layer forming coating solution (A1). ..

-Formation of elastic layer As elastic materials, 30 parts of chloroprene rubber (CR) (WRT: manufactured by Showa Denko Co., Ltd.) and 70 parts of ethylene, propylene, diene rubber (EPDM) (esprene 505: manufactured by Sumitomo Chemical Co., Ltd.) are used with a pressure kneader. After kneading, 30 parts of carbon black (Denka Black (acetylene black): manufactured by Denka) as an electronic conductive agent, 5 parts of zinc oxide (manufactured by Nippon Kagaku Kogyo Co., Ltd.) and 5 parts of magnesium oxide (manufactured by Kyowa Chemical Co., Ltd.) as fillers. Part, 1 part of sulfur vulcanization agent (Sulfax PMC: manufactured by Tsurumi Chemical Industry Co., Ltd.), 1 part of vulcanization accelerator (Noxeller TS: manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and 1 part of vulcanization accelerator (Noxeller DT: Ouchi) (Manufactured by Shinko Kagaku Kogyo Co., Ltd.) 1 part was added and further kneaded with two heating rolls. This kneaded product was extruded into a belt shape and coated on a metal cylinder surface called a vulcanized mandrel, which had an outer diameter of the same size as the inner diameter of the belt. Then, it was vulcanized at 170 ° C. for 1 hour in a saturated steam high-pressure can.

-Formation of resin layer (preparation of belt member)
A coating liquid (A1: coating liquid for forming a resin layer) is applied on an elastic layer coated and molded on a metal cylinder surface by a flow coating (spiral coating) device, dried at 175 ° C. for 15 minutes, and coated with a resin layer. A film was formed.
Then, it was fired at 200 ° C. for 80 minutes and removed from the mold.

・ Polishing treatment The demolded belt is held by applying tension with multiple tension rolls, and while rotating this belt, a grindstone that rotates in the With direction (in the same direction) is brought into contact with the inner peripheral surface of the belt. Traverse polishing was performed.

For the belt member thus obtained, the JIS-A hardness, roughness (arithmetic mean roughness Ra, maximum height Rz), average thickness, elastic modulus of the resin layer, and average thickness of the inner peripheral surface of the elastic layer are determined. Each was measured by the method described above.

[Example 2]
In the production of the belt member in Example 1, the hardness of the elastic layer was adjusted by adjusting the blending amounts of chloroprene rubber (CR), ethylene / propylene / diene rubber (EPDM), electron conductive agent, filler, and sulfur vulcanizing agent. Was changed to the value shown in Table 1 below.
Further, the polishing conditions of the inner peripheral surface of the belt member were changed so as to be in the state of Ra 1 μm and Rz 3 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Example 3]
In the production of the belt member in Example 1, the hardness of the elastic layer was adjusted by adjusting the blending amounts of chloroprene rubber (CR), ethylene / propylene / diene rubber (EPDM), electron conductive agent, filler, and sulfur vulcanizing agent. Was changed to the value shown in Table 1 below.
Further, the polishing conditions of the inner peripheral surface of the belt member were changed so as to be in the state of Ra 5 μm and Rz 8 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Example 4]
In the production of the belt member in Example 1, the hardness of the elastic layer was adjusted by adjusting the blending amounts of chloroprene rubber (CR), ethylene / propylene / diene rubber (EPDM), electron conductive agent, filler, and sulfur vulcanizing agent. Was changed to the value shown in Table 1 below.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Example 5]
In the production of the belt member in Example 1, the hardness of the elastic layer was adjusted by adjusting the blending amounts of chloroprene rubber (CR), ethylene / propylene / diene rubber (EPDM), electron conductive agent, filler, and sulfur vulcanizing agent. Changed to the value shown in Table 1 below.
Further, the coating amount when the resin layer forming coating liquid (A1) was applied by the flow coating (spiral coating) device was changed so that the thickness of the resin layer became an average thickness of 65 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Comparative Example 1]
In Example 1, only the resin layer was formed without forming the elastic layer. At that time, the amount of coating when the resin layer forming coating liquid (A1) was applied was adjusted by the flow coating (spiral coating) device to form the resin layer having the thickness shown in Table 1 below.
Further, the polishing conditions of the inner peripheral surface of the belt member were changed so as to be in the state of Ra 2 μm and Rz 5 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Comparative Example 2]
In Example 1, only the resin layer was formed without forming the elastic layer.
Further, the polishing conditions of the inner peripheral surface of the belt member were changed so as to be in the state of Ra 2 μm and Rz 8 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

[Comparative Example 3]
In Example 1, a release layer was formed instead of the resin layer. That is, a two-component curable water-based polyurethane resin (Bonderite S-FN345, Henkel Co., Ltd.) containing polytetrafluoroethylene (PTFE) as a coating liquid for forming a release layer instead of the coating liquid (A1) for forming a resin layer. Manufactured, pencil hardness H, PTFE: containing 15% by mass) was used. This is applied by spray coating on an elastic layer coated and molded on a metal cylinder surface so as to have a film thickness of 5 μm (thickness after drying and curing), and then heated at 120 ° C. for 30 minutes for curing treatment. went.
Further, the conditions of extrusion processing at the time of forming the elastic layer were changed so that the thickness of the elastic layer became an average thickness of 450 μm.
Further, the polishing conditions of the inner peripheral surface of the belt member were changed so as to be in the state of Ra 1 μm and Rz 5 μm.
Except for this, a belt member was obtained in the same manner as in Example 1.

-Evaluation test-
-Durability evaluation Using the obtained belt member, the durability was evaluated by the following method.
The obtained belt member was used as an intermediate transfer belt and incorporated into an image forming apparatus (DocuPrintCP200W, manufactured by Fuji Xerox Co., Ltd.). However, as a roll for hanging the belt member, a meandering suppressing member that applies tension to the belt and suppresses the meandering of the belt (when the belt member tries to meander to one side in the roll axial direction, the axial direction of the belt member). A belt is provided by providing a wall member (a wall member that collides with the end face (side surface) and suppresses meandering) at the end in the roll axis direction, and by controlling the tilt angle of the roll shaft so that the roll shaft can be tilted. A tension applying roll having a function of suppressing meandering was used. Then, the operation of the tension applying roll over which the belt member is hung is fixed in a state where it is set at the position of the upper limit of the correction range (that is, the inclination angle of the roll axis of the tension applying roll is increased to the control limit angle). The belt member was continuously rotationally driven. The belt member was continuously rotated with the end face (side surface) abutting against the meandering suppressing member (wall member). This rotation operation is performed a certain number of times (rotation speed equivalent to 100,000 sheets of image formation on A4 paper) to stop, and the state of the belt such as scratches on the end portion and end surface (side surface) of the belt member and surface scratches is checked. confirmed.
(Evaluation criteria)
A (○): No abnormality in the belt after evaluation B (×): There is an abnormality in the belt after evaluation

-Evaluation of image deviation (color registration) Using the obtained belt member, image deviation (color registration) was evaluated by the following method.
The obtained belt member was used as an intermediate transfer belt and incorporated into an image forming apparatus (DocuPrintCP200W, manufactured by Fuji Xerox Co., Ltd.). A transfer image is formed on 10 sheets of paper, the position of the transfer image is measured for all the sheets, and the position of the transfer image and the target position of the original image (the target position where the image was planned to be formed) in the paper transport direction. ) Was calculated. The average value of this difference was calculated and evaluated according to the following criteria.
(Evaluation criteria)
A (○): Position difference 50 μm or less B (Δ): Position difference 50 μm or more 100 μm or less C (×): Position difference 100 μm or less

-Evaluation of transferability Using the obtained belt member, the transferability was evaluated by the following method.
The obtained belt member was incorporated into an image forming apparatus (DocuPrintCP200W, manufactured by Fuji Xerox Co., Ltd.) as an intermediate transfer belt, and the quality of the transferred image when the toner image formed on the belt member was transferred onto paper was evaluated.
(Evaluation criteria)
A (○): No abnormality in the quality of the transferred image B (×): The transfer rate of the toner image is reduced.

From the results shown in Table 1, in this embodiment, as compared with the comparative example, the plurality of rolls are laid out in a tensioned state in the image forming apparatus and arranged so as to form a nip with other members. It can be seen that the occurrence of image misalignment that occurs when the image is used to form an image in the state of being used is suppressed.

1Y, 1M, 1C, 1K Image forming unit 11 Photoreceptor (image holder)
12 Charger 13 Laser exposure device 14 Developer 15 Intermediate transfer belt (belt member)
15A resin layer (surface layer)
15B Elastic layer 16 Primary transfer roll 17 Photoconductor cleaner 20 Secondary transfer part 22 Secondary transfer roll 25 Back roll 26 Feeding roll 31 Drive roll 32 Support roll 33 Tensioning roll 34 Cleaning Back roll 35 Intermediate transfer belt cleaner 40 Control unit 42 Reference sensor 43 Image density sensor 50 Paper storage section 51 Paper feed roll 52 Transport roll 53 Transport guide 55 Transport belt 56 Fixing inlet guide 60 Fixing device 100 Image forming device 113 Cleaning facing roll 131, 132 Roll 150 Belt member unit 200 Image forming Equipment 201BK, 201C, 201M, 201Y Photoreceptor drum 202BK, 202C, 202M, 202Y Charger 203BK Black developing device 203C Cyan developing device 203M Magenta developing device 203Y Yellow developing device 204BK, 204C, 204M, 204Y Photoreceptor drum cleaning member 205BK, 205C, 205M, 205Y Transfer roll 206 Belt support roll 207 Paper transfer belt 208 Paper transfer roll 210 Fixing device 212 Cleaning blade 213 Opposing roll for cleaning 214BK, 214C, 214M, 214Y Exposure 215 Paper (recording medium)
220 Paper Conveyor Belt Cleaning Equipment

Claims (6)

An elastic layer that constitutes the inner peripheral surface and has a JIS-A hardness of 50 ° or more and 90 ° or less.
A resin layer that constitutes the outer peripheral surface and has an elastic modulus of 2000 MPa or more and 6000 MPa or less.
Have a,
In the inner peripheral surface, the arithmetic average roughness Ra (JIS-B0601: 2001 years) is not more 2μm or less, and a maximum height Rz: belt for (JIS-B0601 2001 years) of the image forming apparatus Ru der below 7μm Element. The belt member according to claim 1, wherein the average thickness of the resin layer is 50 μm or more and 70 μm or less. The belt member according to claim 1 or 2 , wherein the average thickness of the elastic layer is 300 μm or more and 600 μm or less. The belt member according to any one of claims 1 to 3 , wherein the resin layer contains at least one resin selected from the group consisting of a polyimide resin and a polyamide-imide resin. The belt member according to any one of claims 1 to 4.
A plurality of rolls for hanging the belt member under tension, and
A belt member unit that is attached to and detached from the image forming apparatus. Image holder and
A charging means for charging the surface of the image holder and
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image holder, and
A developing means that accommodates a developer containing toner and develops a static charge image formed on the surface of the image holder by the developer as a toner image.
The toner image having the belt member unit according to claim 5 , the toner image formed on the surface of the image holder is primarily transferred to the outer peripheral surface of the belt member, and the toner image transferred to the belt member is recorded as a recording medium. And the transfer means for secondary transfer to
An image forming apparatus comprising.

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