JP2020086077A - Developer carrier, process cartridge, and electrophotographic device - Google Patents

Abstract

To provide a developer carrier which is less susceptible to scratches on a surface thereof even after prolonged use and offers superior image uniformity.SOLUTION: A developer carrier provided herein comprises a conductive base material and a surface layer containing at least one resin selected from acrylic resins and methacrylic resins, the one resin having a plurality of constituent units linked by a linking group, where the linking group contains a plurality of urethane bonds and a tertiary amine structure represented by a structural formula (1) below.SELECTED DRAWING: None

Description

The present invention relates to a developer carrier used in an electrophotographic apparatus, a process cartridge having the developer carrier, and an electrophotographic apparatus.

In an electrophotographic apparatus (electrophotographic copying machine, facsimile, printer, etc.), a developer carrier that conveys a developer for developing an electrostatic latent image formed on an electrophotographic photosensitive member to a developing area. The body is used. With the recent demand for even longer life of the electrophotographic image forming apparatus, further durability is required for the developer carrier. Patent Document 1 discloses an electrophotographic member that enables long-term use by disposing an acrylic urethane resin layer having scratch resistance on the surface. Further, Patent Document 2 uses an amino compound having a specific structure to facilitate interaction between urethane bonds or urea bonds in the urethane resin. As a result, a reinforcing effect is exhibited by each physical crosslinking (pseudo-crosslinking), and a developer carrier having improved set resistance is disclosed.

JP, 2011-186433, A JP, 2014-29496, A

According to the studies by the present inventors, the electrophotographic members according to Patent Document 1 and Patent Document 2 still have room for improvement in scratch resistance of the surface when used for a long period of time. Specifically, for example, when used for a long period of time under a low temperature and low humidity environment (hereinafter sometimes referred to as “L/L environment”) such as a temperature of 10° C. and a relative humidity of 15%, the outer surface The surface roughness may change over time due to scratches. When the surface roughness changes, the developer carrying amount may change, and the density of the electrophotographic image may change over time.
One aspect of the present invention is directed to providing a developer carrier whose surface roughness is unlikely to change even after long-term use.
Another aspect of the present invention is directed to providing a process cartridge that contributes to stable formation of high-quality electrophotographic images. Furthermore, another aspect of the present invention is directed to providing an electrophotographic image forming apparatus capable of forming a high-quality electrophotographic image.

According to one aspect of the present invention, there is provided a developer carrier having a conductive substrate and a surface layer, the surface layer containing at least one resin selected from an acrylic resin and a methacrylic resin. A plurality of units constituting the resin are linked by a linking group, and the linking group includes a plurality of urethane bonds and a developer carrying member containing a tertiary amine structure represented by the following structural formula (1). Will be provided.

[In the structural formula (1),
R11 represents a linear or branched alkylene group having 2 to 4 carbon atoms, n represents an integer of 2 or more and 4 or less,
The symbols "*1", "*2", "*3", and n "*4" are each independently,
A bond with a hydrogen atom,
A bond with an alkyl group having 1 to 4 carbon atoms,
A bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms,
A bond with a linear or branched aminoalkyl group having 1 to 4 carbon atoms, or
A bond between the urethane bond and a non-carbonyl oxygen atom,
However, at least four selected from “*1”, “*2”, “*3”, and n “*4” are the bonding portions of the urethane bond with the non-carbonyl oxygen atom, and
At least one of n “*4” is a bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, or a linear or branched chain having 1 to 4 carbon atoms. It is a bond with a chain aminoalkyl group. ].
According to another aspect of the present invention, there is provided a process cartridge detachably mountable to a main body of an electrophotographic apparatus, comprising a toner container containing toner, and a developer carrier for carrying the toner, There is provided a process cartridge in which the developer carrier is the above developer carrier.
Furthermore, according to another aspect of the present invention, an electrophotographic photosensitive member, a charging member arranged to charge the electrophotographic photosensitive member, and a developer carrying member for supplying toner to the electrophotographic photosensitive member are provided. An electrophotographic image forming apparatus having the above developer carrier is provided.

According to one aspect of the present invention, it is possible to obtain a developer carrier which is unlikely to be scratched on the surface even when used for a long period of time and whose surface roughness is unlikely to change. Further, according to another aspect of the present invention, it is possible to obtain a process cartridge that contributes to stable formation of a high-quality electrophotographic image. Further, according to another aspect of the present invention, it is possible to obtain an electrophotographic image forming apparatus capable of forming a high quality electrophotographic image.

It is a conceptual diagram which shows an example of the developer carrying body of this invention. It is a schematic structure figure showing an example of a process cartridge of the present invention. 1 is a schematic configuration diagram showing an example of an electrophotographic apparatus of the present invention. It is an image figure which shows an example of the resin structure which forms the surface layer of this invention.

<Developer carrier>
A roller-shaped developer bearing member according to an aspect of the present invention (hereinafter, also referred to as “developing roller”).
1 is a sectional view in a direction orthogonal to the axial direction of ().
As shown in FIG. 1A, the developing roller 1 includes a columnar or hollow cylindrical substrate 2 and a surface layer 4, and further includes an elastic layer 3 between the substrate 2 and the surface layer 4. is doing. That is, this developing roller has a substrate, an elastic layer on the substrate, and a surface layer on the elastic layer.
As another configuration of the developing roller 1, as shown in FIG. 1B, a three-layer structure in which an intermediate layer 5 is disposed between the elastic layer 3 and the surface layer 4, or a configuration in which a large number of intermediate layers 5 are disposed May be As the intermediate layer, a known intermediate layer for a developer carrier can be used.
<Surface layer>
The surface layer contains at least one resin selected from acrylic resin and methacrylic resin. Hereinafter, in the present specification, the acrylic resin and the methacrylic resin may be collectively referred to as “(meth)acrylic resin”.
Further, in the resin, a plurality of units constituting the resin are connected by a connecting group, and the connecting group has a plurality of urethane bonds and a tertiary amine structure represented by the following structural formula (1). Including.

In structural formula (1),
R11 represents a linear or branched alkylene group having 2 to 4 carbon atoms,
n represents an integer of 2 or more and 4 or less,
The symbols "*1", "*2", "*3", and n "*4" are each independently,
A bond with a hydrogen atom,
A bond with an alkyl group having 1 to 4 carbon atoms,
A bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms,
A bond with a linear or branched aminoalkyl group having 1 to 4 carbon atoms, or
A bond between the urethane bond and a non-carbonyl oxygen atom,
However, at least four selected from “*1”, “*2”, “*3”, and n “*4” are the bonding portions of the urethane bond with the non-carbonyl oxygen atom,
At least one of n “*4” is a bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, or a linear or branched chain having 1 to 4 carbon atoms. It is a bond with a chain aminoalkyl group.

[Explanation of structure that improves scratch resistance]
The present inventors presume the reason why a developer carrier that is excellent in scratch resistance and contributes to prolonging the life can be obtained by including the above surface layer even in a low temperature and low humidity environment as follows.
In the surface layer, as shown in FIG. 4, a unit in the first polymer chain and a unit in the second polymer chain constituting the (meth)acrylic resin have a plurality of urethane bonds and a tertiary amine. And a connecting group having a structure.
That is, the linking group includes the partial structure represented by Structural Formula (1), and the partial structure contains a plurality of nitrogen atoms. Further, since the number of repetitions n of the repeating structural unit in the partial structure represented by the structural formula (1) is an integer of 2 or more and 4 or less, the nitrogen atom in the structural formula (1) is bonded to its bond. There are three types of groups, depending on the groups they are working with:
(I) a nitrogen atom bonded to *1, *2 and R11;
(Ii) *4 and a nitrogen atom bonded to two R11;
(Iii) A nitrogen atom bonded to R11, *3 and *4.
The nitrogen atom classified in the above (ii) includes a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, or a linear or branched aminoalkyl group having 1 to 4 carbon atoms. The groups are attached. Therefore, in the surface layer, the hydrogen atom in the hydroxyalkyl group or the aminoalkyl group is, as shown in FIG. 4, a carbonyl oxygen atom or other tertiary nitrogen atom constituting the urethane bond of the linking group. Is believed to form hydrogen bonds with.
Generally, in the image forming process, the outer surface of the developer carrying member is always subjected to a contact pressure from another member via the toner. Therefore, the toner acts like an abrasive and the image forming process is continued for a long period of time, whereby fine scratches are likely to occur on the outer surface of the developer carrying member.
However, as described above, in the surface layer according to this embodiment, when the contact pressure is applied, first, the hydrogen bond derived from the hydroxyalkyl group or the aminoalkyl group in the linking group is cleaved and added to the surface layer. Stress is relieved. As a result, it is considered that breakage of the polymer chain itself can be suppressed. Since the hydrogen bond is easily regenerated even if it is once broken, it is considered that even if a slight scratch is generated on the outer surface of the developer carrying member, the slight scratch can be repaired. ..
Further, regarding the resin, each of the units preferably has a structure represented by the following structural formula (2). When the unit constituting the resin has the structure represented by the structural formula (2), the scratch resistance of the outer surface of the surface layer can be further improved.

In the structural formula (2), R12 represents a hydrogen atom or a methyl group, and A1 has a structure represented by the following structural formula (3).
**-R13-O-CONH-B1-NHCO-O*** Structural formula (3).
In structural formula (3), R13 represents a linear or branched alkylene group having 1 to 4 carbon atoms.
The symbol “**” is a bond to a non-carbonyl oxygen atom in the structure represented by the structural formula (2), and the symbol “***” is “*1” or “” in the structural formula (1). *2", "*3", and any one selected from n "*4".
B1 represents either the following structural formula (4) or structural formula (5).

In the structural formula (4), the symbols “*B1” and “*B2” respectively represent the bond part with each nitrogen atom of the two urethane bonds in the structural formula (3).
In the structural formula (5), the symbols “*B3” and “*B4” respectively represent the bonding part with each nitrogen atom of the two urethane bonds in the structural formula (3).
The reason why the scratch resistance of the surface layer can be further improved by using each of the units as the resin having the structure represented by the structural formula (2) is not necessarily restricted by the following theory. , Is guessed as follows.
Each of the units has a structure represented by the structural formula (2). In the resin, the units forming the (meth)acrylic resin are bonded by a linking group having a urethane bond, a tertiary amine structure, and an aromatic ring. It can be seen as having a structure that has been made.
When an aromatic ring such as a benzene ring is present in the linking group, the interaction with the hydroxyalkyl group or the aminoalkyl group bonded to the nitrogen atom in the above (ii) causes the interaction between the two aromatic rings. It is considered to occur. That is, the interaction between the π electron of the aromatic ring and the hydroxyl group (—OH) in the hydroxyalkyl group or the amino group (—NH ₂ ) in the aminoalkyl group (for example, T-type stacking effect) or two It is considered that the π-π stacking interaction is expressed between the aromatic rings. It is considered that these interactions exhibit the same action as the above-mentioned hydrogen bond and can further improve the scratch resistance of the outer surface of the surface layer.
[Resin synthesis method]
The resin can be composed of, for example, (meth)acrylic polyol, isocyanate, and a tertiary amine compound as raw materials.
Specifically, for example, a step of reacting a (meth)acrylic polyol with a diisocyanate to obtain an isocyanate prepolymer (hereinafter, also referred to as “step (1)”), and an isocyanate group of the isocyanate prepolymer and To react with a hydroxyl group or an amino group of an amino compound to synthesize a (meth)acrylic resin having a unit linked by a linking group having a urethane bond and a tertiary amine structure (hereinafter, referred to as “step (2 )”)).
Hereinafter, these constituent components will be described.
[Acrylic polyol]
The (meth)acrylic polyol, which is a raw material of the (meth)acrylic resin, is not particularly limited in structure. Generally, a (meth)acrylic polyol is obtained by polymerizing at least one of an acrylate having a hydroxyl group and a methacrylate having a hydroxyl group. In the case of a monomer such as (meth)acrylate, an acrylic polyol is produced by a double bond portion derived from acrylic acid undergoing addition reaction between monomers (addition polymerization).
Specific examples of the (meth)acrylate having a hydroxy group include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. Can be mentioned.
[Isocyanate]
The isocyanate is not particularly limited, and known isocyanate can be used.
Examples of isocyanates include aliphatic polyisocyanates such as ethylene diisocyanate and 1,6-hexamethylene diisocyanate (HDI), and fats such as isophorone diisocyanate (IPDI), cyclohexane-1,3-diisocyanate and cyclohexane-1,4-diisocyanate. Aromatic isocyanates such as cyclic polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate And isocyanate compounds such as their copolymers, isocyanurates, TMP adducts, biurets, and their blocks. At least one of these can be used.
Here, when an aromatic isocyanate is selected as the isocyanate, an aromatic ring can be introduced into the linking group as described above.
[Amino compound]
Examples of the raw material for the tertiary amine structure include amino compounds represented by the following structural formula (6).

In structural formula (6),
R25 represents a linear or branched alkylene group having 2 to 4 carbon atoms,
n21 represents an integer of 2 or more and 4 or less.
R21, R22, R23 and n21 R24s are each independently
A bond with a hydrogen atom,
A bond with an alkyl group having 1 to 4 carbon atoms,
A bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms,
It is a bond with a linear or branched aminoalkyl group having 1 to 4 carbon atoms.
In addition, at least one of n21 R24 is a bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, or a linear or branched chain having 1 to 4 carbon atoms. It is a bond with the aminoalkyl group.
In particular, R24 bonded to the nitrogen atom bonded to two R25 is a bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms or a linear chain having 1 to 4 carbon atoms. It is preferably a bond with a linear or branched aminoalkyl group. Such a hydroxyalkyl group or a hydroxyamino group bonded to a nitrogen atom is located in a sterically crowded portion as compared with a hydroxyalkyl group or a hydroxyamino group bonded to another nitrogen atom. Therefore, the reactivity with the isocyanate compound is low, and the compound easily exists in the linking group even after the step (2).
In addition, examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the linear or branched hydroxyalkyl group having 1 to 4 carbon atoms include hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group and 2-hydroxypropyl group. Further, examples of the linear or branched aminoalkyl group having 1 to 4 carbon atoms include aminoethyl group, aminopropyl group, and aminobutyl group.
Examples of the compound represented by Structural Formula (6) include the compound represented by Structural Formula (9).

[Polyol]
As a material for forming the surface layer, in addition to the above materials, a polyol other than an acrylic polyol may be included within a range not impairing the effects of the present invention. The polyol has a plurality of hydroxyl groups in the molecule, and the hydroxyl groups react with the polyisocyanate.
The polyol other than the acrylic polyol is not particularly limited, and examples thereof include polyether polyol and polyester polyol. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol and polytetramethylene glycol. As the polyester polyol, diol components such as 1,4-butanediol, 3-methyl-1,4-pentanediol and neopentyl glycol, triol components such as trimethylolpropane, adipic acid, phthalic anhydride, Examples thereof include polyester polyols obtained by condensation reaction with dicarboxylic acids such as terephthalic acid and hexahydroxyphthalic acid, or carboxylic acid anhydrides.
The polyether polyols and polyester polyols may be prepolymers chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4 diphenylmethane diisocyanate (MDI) or isophorone diisocyanate (IPDI) in advance, if necessary. ..

[Additive]
The surface layer is a general resin other than the resin according to the present invention, a rubber material, a compounding agent, a conductivity-imparting agent, a non-conductive filler, a cross-linking agent, a catalyst, if necessary, to the extent that the effects of the present invention are not impaired May be added. The resin to be added is not particularly limited, for example, epoxy resin, urethane resin, urea resin, ester resin, amide resin, imide resin, amide imide resin, phenol resin, vinyl resin, silicone resin, fluororesin, etc. Can be mentioned. Examples of the rubber material include ethylene-propylene-diene copolymer rubber, acrylonitrile-butadiene rubber, chloroprene rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, silicone rubber, epichlorohydrin rubber and urethane rubber.
Examples of the compounding agent include fillers, softening agents, processing aids, tackifiers, anti-tacking agents, foaming agents and the like which are generally used for resins.
As the conductivity-imparting agent, fine particles of carbon black; conductive metals such as aluminum and copper; conductive metal oxides such as conductive zinc oxide, conductive tin oxide and conductive titanium oxide can be used. Non-conductive fillers include silica, quartz powder, titanium oxide, or calcium carbonate. The cross-linking agent is not particularly limited, but examples thereof include tetraethoxysilane, di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane or dicumyl. Examples include peroxides. Further, conductivity can be imparted by using an ionic conductive agent or an ionic liquid. These can be either a fixed type containing a reactive group with the binder resin or a non-fixed type containing no reactive group with the binder resin.
When surface roughness is required for the surface layer of the developer carrying member, fine particles for roughness control may be added to the surface layer. As the roughness controlling fine particles, it is preferable that the volume average particle diameter is 3 to 20 μm, since a developer carrier having an excellent toner conveying ability can be obtained. The amount of fine particles added to the surface layer is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin solid content of the surface layer in order not to impair the effects of the present invention. As the roughness controlling fine particles, fine particles of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, or phenol resin can be used. Examples of the polyurethane resin particles include Dimic beads (trade name, manufactured by Dainichiseika Kogyo Co., Ltd.) series, Art Pearl (trade name, manufactured by Negami Kogyo Co., Ltd.) series, and the like.

<Substrate>
The substrate functions as an electrode and a supporting member of the developer carrier, and is, for example, a metal or alloy such as aluminum, copper alloy, and stainless steel; iron plated with chromium or nickel; synthetic with conductivity. It is made of a conductive material such as resin. The substrate may be solid or hollow.
<Elastic layer>
As a constituent material of the elastic layer, a known material for the elastic layer or a material that can be used for the elastic layer can be used. It is preferable that the elastic layer is usually formed of a molded body of a rubber material.
As the rubber material, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR). ), fluororubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, urethane rubber and the like. These may be used alone or in admixture of two or more.
Among these, silicone rubber is particularly preferable because it is unlikely to cause compression set in the elastic layer even when another member is in contact with it for a long period of time. Examples of the silicone rubber include cured products of addition-curable silicone rubber. Furthermore, it is particularly preferable to use a cured product of addition-curable dimethyl silicone rubber.
Various additives such as a conductivity-imparting agent, a non-conductive filler, a cross-linking agent, and a catalyst are appropriately mixed in the elastic layer 3. As the conductivity-imparting agent, fine particles of carbon black; conductive metals such as aluminum and copper; and conductive metal oxides such as zinc oxide, tin oxide and titanium oxide can be used. At least one of these can be used. Of these, carbon black is particularly preferable because it is relatively easily available and has good conductivity. When carbon black is used as the conductivity-imparting agent, it is preferably added in an amount of 2 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the rubber material in the material for forming the elastic layer.
Non-conductive fillers include silica, quartz powder, titanium oxide, zinc oxide or calcium carbonate. At least one of these can be used.
Examples of the cross-linking agent include di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and dicumyl peroxide. At least one of these can be used.
<Treatment of substrate>
When forming the elastic layer on the substrate, it is treated with an alkaline solution to generate hydroxyl groups on the substrate, hydrogen bonds are formed between the substrate surface and the elastic layer, and adhesion is improved. Can be made Also, due to the relationship of the finishing process, the parts (for example, both ends) which are inconvenient when brought into close contact with each other can be treated by the following process to improve the separability. That is, after treating the substrate with an alkaline solution, a polycarboxylic acid such as citric acid or malic acid is applied to the surface. At this time, a solvent such as water or MEK may be used. By this step, it is expected that the polycarboxylic acid will be coordinated with the hydroxyl groups formed on the substrate, and that no particular adhesion action will occur between the substrate surface and the elastic layer.

<Developer>
The developer carrier according to each aspect of the present invention can be applied to those using a magnetic one-component developer or a non-magnetic one-component developer. Further, the developer carrying member according to each aspect of the present invention is a developing device which is not in contact with the electrophotographic photosensitive member, a developing device in which the developer carrying member is in contact with the electrophotographic photosensitive member, and two-component development. It can be applied to a developing device using an agent.
<Process cartridge, electrophotographic device>
A process cartridge and an electrophotographic apparatus according to an aspect of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these. FIG. 2 is a schematic configuration diagram showing an example of a process cartridge detachably attached to a main body of an electrophotographic apparatus, which includes a developer carrying member according to an aspect of the present invention as a developing member. FIG. 3 is a schematic configuration diagram showing an example of an electrophotographic apparatus when the process cartridge is attached to the main body of the electrophotographic apparatus.
The process cartridge shown in FIG. 2 has a toner container 9, a developer carrier 7, a developer regulating member 17, and a developer supply member 8, and is detachably provided in the main body of the electrophotographic apparatus. ing. In FIG. 3, the electrostatic latent image carrier 18, which is the image carrier on which the electrostatic latent image is formed, is rotated in the direction of arrow R1. By rotating the developer carrying member 7 in the direction of arrow R2, the developer is carried to the developing area where the developer carrying member 7 and the electrostatic latent image carrying member 18 face each other. The electrophotographic apparatus according to this aspect employs a so-called contact developing system in which the developer carrier 7 is arranged in contact with the electrostatic latent image carrier 18. Further, a developer supply member 8 is in contact with the developer carrier 7, rotates in the R3 direction, and supplies the developer to the surface of the developer carrier 7.
Around the electrostatic latent image carrier 18, a charging roller 6 serving as a charging member, a transfer member (transfer roller) 10, a cleaner container 11, a cleaning blade 12, a fixing device 13, and a pickup roller 14 are arranged so as to be chargeable. It is provided. The electrostatic latent image carrier 18 is charged by the charging roller 6. Then, the laser generator 16 irradiates the electrostatic latent image carrier 18 with laser light to perform exposure, and an electrostatic latent image corresponding to a target image is formed. The electrostatic latent image on the electrostatic latent image carrier 18 is developed by the developer in the toner container 9 carried by the developer carrier 7 and included in the process cartridge as the developing device. The development is so-called reversal development in which the developer is developed in the exposed area.
The transfer material (paper) P is conveyed from the paper feeding unit 15 into the apparatus by the pickup roller 14 and the like, and the image is transferred to the electrostatic latent image carrier 18 via the transfer material (paper) P. It is transferred onto the transfer material (paper) P by the transfer roller 10. The transfer material (paper) P on which the image is placed is conveyed to the fixing device 13, and the developer is fixed on the transfer material (paper) P. The developer remaining on the electrostatic latent image carrier 18 is scraped off by the cleaning blade 12 and stored in the cleaner container 11.
It is preferable that the developer regulating member 17 contacts the developer carrying member 7 via the developer to regulate the thickness of the developer layer on the developer carrying member. A regulating blade is generally used as the developer regulating member that comes into contact with the developer carrying member, and can be suitably used in the electrophotographic apparatus according to this aspect.
As the material forming the above-mentioned regulation blade, a rubber elastic body such as silicone rubber, urethane rubber or NBR; a synthetic resin elastic body such as polyethylene terephthalate; a metal elastic body such as a phosphor bronze plate or a stainless steel (SUS) plate can be used. Further, it may be a complex thereof. Further, in order to control the chargeability of the developer, a structure in which a charge control material such as resin, rubber, metal oxide or metal is attached to an elastic support such as rubber, synthetic resin or metal elastic body You can also In this case, the regulation blade is used so that the portion of the charge control material becomes the contact portion with the developer carrying member. As such a regulating blade, a metallic elastic body to which resin or rubber is attached is particularly preferable. As these resins or rubbers, urethane rubber, urethane resin, polyamide resin, nylon resin and the like, which are easily positively charged, are preferable.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. However, the present invention is not limited to these examples.

<<Preparation of substrate>>
A ground cylindrical aluminum tube having an outer diameter of 10 mm and an arithmetic mean roughness Ra of 0.3 μm was prepared as a substrate. The substrate was surface-treated by immersing it for 3 minutes in a cleaning tank adjusted to pH=12.0. Next, further surface treatment was performed for the convenience of processing for adjusting the end face shape later. That is, in order to easily remove the layer formed from both ends of the cylindrical tube to the part 0.5 mm inside, the entire peripheral surface from both ends to 0.5 mm inside is treated with 0.01% citric acid aqueous solution. By applying, a substrate Z-1 as a raw material of the example or the comparative example was obtained.

<<Preparation of Elastic Roller K-1>>
The prepared base Z-1 was placed in a mold, and an addition type silicone rubber composition in which the materials shown below were mixed was injected into the cavity formed in the mold.
・Liquid silicone rubber material (trade name SE6724A/B; manufactured by Toray Dow Corning)
100 parts by mass carbon black (trade name Toka Black #4300; manufactured by Tokai Carbon Co., Ltd.)
15 parts by mass/silica powder (as a heat resistance imparting agent) 0.2 parts by mass/platinum catalyst 0.1 parts by mass Subsequently, the mold is heated to cure the silicone rubber at a temperature of 150° C. for 15 minutes to cure it. It was After demolding the substrate on which the cured silicone rubber layer was formed on the peripheral surface, the substrate was further heated at a temperature of 180° C. for 1 hour to complete the curing reaction of the silicone rubber layer. In this way, an elastic roller K-1 in which a silicone rubber elastic layer having a film thickness of 0.7 mm and a diameter of 11.4 mm was formed on the outer circumference of the substrate was produced.

<<Preparation of Raw Materials for Surface Layer Formation>>
<Synthesis of isocyanate group-terminated prepolymer>
An example of synthesizing an isocyanate group-terminated prepolymer, which is one of the raw materials for synthesizing the urethane resin for the surface layer, is shown.
(Preparation of acrylic polyol)
First, raw material acrylic monomers M-1 to M-5 used for the synthesis of the isocyanate group-terminated prepolymer were prepared. The commercial products shown in Table 1 were used for all of these.

Acrylic polyol was synthesized using the above monomers.
(Acrylic polyol B-1)
A reaction vessel equipped with a stirrer, a thermometer, a reflux pipe, a dropping device and a nitrogen gas introduction pipe was charged with 300 parts by mass of dry methyl ethyl ketone, heated to a temperature of 87° C. under a nitrogen gas stream, and heated under reflux. Next, a mixture of 100.0 parts by mass of the raw material acrylic monomer M-1 (2-hydroxyethyl acrylate) and 0.2 parts by mass of an initiator (trade name, Kayaester O; manufactured by Kayaku Akzo Co., Ltd.) for 1 hour. It dripped gradually over. Then, the mixture was heated and refluxed for 3 hours while maintaining the temperature at 87°C. Next, it was left to cool and the temperature was lowered to room temperature to obtain acrylic polyol B-1. The number average molecular weight was about 3000, and the hydroxyl value was 126 mgKOH/g.
(Acrylic polyol B-2 to B-5)
Acrylic polyols B-2 to B-5 were synthesized in the same manner as the above-mentioned method for synthesizing acrylic polyol B-1. The structure, molecular weight and hydroxyl value are shown in the following structural formula (7) and Table 2.

(Preparation of polyols other than acrylic polyol)
Polyol compounds other than the acrylic polyols shown in Table 3 below were prepared.

(Preparation of raw material isocyanate and urethanization catalyst)
C-1 to C-4 shown in Table 4 were prepared as raw material isocyanates for reacting with the acrylic polyol to prepare an isocyanate group-terminated prepolymer described later.

In addition, N,N,N',N'-tetramethyl-1,6-diaminohexane (manufactured by Tokyo Chemical Industry Co., Ltd.) was prepared as a urethane-forming catalyst E-1 for preparing an isocyanate group-terminated prepolymer.

(Synthesis of isocyanate group-terminated prepolymer A-1)
Under a nitrogen atmosphere, 70.2 parts by mass of the raw material isocyanate C-1 was dissolved in methyl ethyl ketone (hereinafter also referred to as MEK) so that the final solid content was 50%. Thereafter, 100.0 parts by mass of acrylic polyol A-1 was gradually added dropwise while maintaining the temperature in the reaction vessel at 65°C.
After completion of the dropping, reaction was carried out at a temperature of 65° C. for 3.0 hours. The obtained reaction mixture was cooled to room temperature to obtain an isocyanate group-terminated prepolymer A-1 having a solid content of 50% and an isocyanate group content of 8.7% by mass.
(Synthesis of isocyanate group-terminated prepolymers A-2 to A-15)
An isocyanate group-terminated prepolymer was prepared in the same manner as in the synthesis of the isocyanate group-terminated prepolymer A-1 except that the acrylic polyol used in the synthesis, the type and amount of the raw material isocyanate, and the reaction time were changed as shown in Table 5. Polymers A-2 to A-15 were obtained as a 50% solids solution.
(Synthesis of isocyanate group-terminated prepolymers A-16, A'-1 and A'-2)
The method for synthesizing the isocyanate group-terminated prepolymer A-1 except that the acrylic polyol, the type and mixing amount of the raw material isocyanate, and the reaction time were set as shown in Table 5 and 0.1 part by mass of the catalyst E-1 was added. Similarly, an isocyanate group-terminated prepolymer A-16 was obtained. Further, in the same manner, isocyanate group-terminated prepolymers A′-1 and A′-2 were obtained using polyols B′-1 and B′-2 other than the acrylic polyol. Each of the isocyanate group-terminated prepolymers was a solution having a solid content of 50%.

<Synthesis of amino compound>
(Synthesis of amino compound D-1)
In a reaction vessel equipped with a stirrer, a thermometer, a dropping device, and a temperature adjusting device, 10.0 g (0.097 mol) of diethylenetriamine as a raw material amino compound and 200 ml of pure water as a reaction solvent were heated to 40°C while stirring. did. Next, while maintaining the reaction temperature at 40° C. or lower, 42.2 g (0.73 mol) of propylene oxide as an additional raw material was gradually added dropwise over 30 minutes. The reaction was carried out by further stirring for 2 hours to obtain a reaction mixture. The obtained reaction mixture was heated under reduced pressure to distill off water to obtain amino compound D-1.
(Synthesis of amino compounds D-2 to D-6 and D'-1)
Amino compounds D-2 to D-6 and D′-1 were synthesized in the same manner as amino compound D-1, except that the types and amounts of the raw material amino compound and the additional raw material were changed as shown in Table 6.

The structures of the obtained amino compounds D-1 to D-6 and D'-1 are shown in Structural Formula (8) and Table 7.

(Example 1)
The following materials were stirred and mixed as materials for the surface layer for explaining the method for producing the developer carrying member of the present invention.
-Reactive compound: Isocyanate group-terminated prepolymer A-1: 88.5 parts by mass-Amino compound: Amino compound D-1: 11.5 parts by mass-Carbon black (trade name MA-230; manufactured by Mitsubishi Chemical Corporation): 20.0 parts by mass urethane resin fine particles (trade name: Art Pearl C-400; manufactured by Negami Kogyo Co., Ltd.): 30.0 parts by mass Next, after adding MEK so that the total solid content ratio becomes 30% by mass, Mixed in a sand mill. Then, the viscosity was further adjusted to 10 to 13 mPa·s with MEK to prepare a surface layer forming coating material. The elastic roller K-1 prepared above was dipped in a coating material for forming a surface layer to form a coating film of the coating material on the surface of the elastic layer of the elastic roller K-1 and dried. Further, by heat-treating at a temperature of 160° C. for 1 hour, a surface layer having a film thickness of about 15 μm is provided on the outer periphery of the elastic layer, both end faces are cut by 0.5 mm to adjust the end shape, and the developer according to Example 1 A carrier was prepared.

(Examples 2-35)
A surface layer-forming coating material was prepared in the same manner as in Example 1 except that the materials shown in Table 8 were used as the surface layer material. Then, each coating material was applied to the elastic roller K-1 in the same manner as in Example 1, dried, and heated to prepare developer carrying bodies according to Examples 2 to 35. In addition, in Examples 32 to 35, the reaction was performed using the prepolymer of the aliphatic isocyanate, but the reactivity was not particularly deteriorated. This is presumed to be the action of the tertiary nitrogen atom in the molecule of the amino compound used.

(Comparative Example 1)
As a material for the surface layer, the preparation method of the coating material for forming a surface layer according to Example 1 except that the isocyanate group-terminated prepolymer A′-1 was 78.2 parts by mass and the polyol D-1 was 21.8 parts by mass. A surface layer-forming coating material according to Comparative Example 1 was prepared in the same manner as in. This surface layer-forming coating material was applied to the surface of the silicone rubber elastic layer of the elastic roller K-1 in the same manner as in Example 1 and dried to form a surface layer, thereby preparing a developer carrying member of Comparative Example 1. ..
(Comparative Examples 2 to 4)
A coating material for forming a surface layer was prepared in the same manner as in Comparative Example 1 except that the material shown in Table 8 was used as the material for the surface layer. Then, the respective coating materials were applied to the elastic roller in the same manner as in Comparative Example 1, dried and heated to prepare developer carrying bodies according to Comparative Examples 2 to 4.
In each of the above-mentioned Examples and Comparative Examples, a bar coater (model number: No. 40) was applied on an aluminum sheet so as to have a film thickness of about 15 μm, thereby producing a test piece for a scratch resistance test. And provided for evaluation. The drying and heating conditions were the same as in the examples.

Regarding the surface layer of the developer carrier obtained in each example, a thermal decomposition device (trade name: Pyro foil sampler JPS-700, manufactured by Nippon Analytical Industry Co., Ltd.) and a GC/MS device (trade name: Focus GC/ISQ) , Thermo Fisher Scientific Co., Ltd.), the thermal decomposition temperature was 590° C., and helium was used as a carrier gas for analysis. As a result, it was confirmed from the obtained fragment peaks that the surface layer had the structure according to the present invention.
For the surface layer obtained in each example, the concentration of the nitrogen atom of the tertiary amine derived from the amino compound in the urethane resin was measured by thermal decomposition GC/MS, or infrared spectroscopy. It can be quantified by a method such as the method (IR).
The developer carrying bodies according to Examples 1 to 35 and Comparative Examples 1 to 4 thus obtained were evaluated for the following items.
<Surface roughness (Ra) measurement>
The surface roughness was measured under the L/L environment before and after the scratch resistance test using the test piece and the image evaluation using the developer carrying member. The surface roughness Ra (JIS B0601) was measured using a surface roughness meter (trade name: Surfcom 480A, manufactured by Tokyo Seimitsu Co., Ltd.), and the value was taken as Ra. As the measurement conditions, a stylus having a radius of 2 μm was used, pressing pressure was 0.7 mN, measurement speed was 0.3 mm/sec, measurement magnification was 5000 times, cutoff wavelength was 0.8 mm, and measurement length was 2.5 mm.
<Scratch resistance test>
The test pieces according to the examples and comparative examples were aged for 24 hours or more under an L/L environment, and Ra was measured. Then, under the same environment, a brush made of SUS304 (trade name: SUS304 stainless steel brush, made by Taiyo Shosha Co., Ltd.) was vertically applied to the test piece, and rubbed 10 times with a load of 10 N, and left for 1 hour. Then, Ra was measured under the same environment, and the values of Ra before and after the evaluation were compared.
<Image evaluation>
The developer carrying member as an evaluation target was loaded into a laser printer (trade name, HP LaserJet Pro M102w Printer, manufactured by Hewlett-Packard Co.) to perform image evaluation. First, the developer carrying body to be evaluated was aged for 24 hours or more under an L/L environment, and Ra was measured. Then, under the same environment, the process cartridge loaded with the developer bearing member was stored in the laser printer main body and left standing for 24 hours or more. Then, a black image having a printing rate of 1% was continuously output on 5,000 sheets. Immediately thereafter, a solid black image was printed on the 5001st sheet, and the in-plane uniformity was evaluated according to the following criteria.
A: Uniform.
B: It is uniform at first glance, but when approaching it, non-uniform parts are recognized.
C: It is non-uniform.
Further, immediately after removing the toner from the process cartridge by air blow, the sample was subjected to surface roughness measurement and compared with the Ra value before evaluation.

<<Evaluation results>>
Table 9 shows the evaluation results. It is recognized that Examples 1 to 35 have excellent scratch resistance because they contain the acrylic resin in which the urethane bond according to the present invention is incorporated in the surface layer. Therefore, in the solid black image, good in-plane uniformity is obtained.
In particular, since Examples 1 to 32 include the partial structure represented by the structural formula (4) or (5), scratch resistance is improved, and it is confirmed that they are particularly favorable.
On the other hand, Comparative Examples 1 to 4 do not satisfy the structure of the present invention. Therefore, the scratch resistance was poor and the image uniformity was poor.

1: developer carrier 2: substrate 3: elastic layer 4: surface layer

Claims (4)

A developer carrier having a conductive substrate and a surface layer,
The surface layer contains at least one resin selected from acrylic resin and methacrylic resin,
The resin has a plurality of units constituting the resin connected by a connecting group,
The linking group has a plurality of urethane bonds and a tertiary amine structure represented by the following structural formula (1).

[In the structural formula (1),
R11 represents a linear or branched alkylene group having 2 to 4 carbon atoms,
n represents an integer of 2 or more and 4 or less,
The symbols “*1”, “*2”, “*3” and n “*4” are each independently a bond with a hydrogen atom, a bond with an alkyl group having 1 to 4 carbon atoms, A bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, a bond with a linear or branched aminoalkyl group having 1 to 4 carbon atoms, or the urethane bond Is a bond with a non-carbonyl oxygen atom,
However, at least four selected from “*1”, “*2”, “*3”, and n “*4” are the bonding portions of the urethane bond with the non-carbonyl oxygen atom,
At least one of n “*4” is a bond with a linear or branched hydroxyalkyl group having 1 to 4 carbon atoms, or a linear or branched chain having 1 to 4 carbon atoms. It is a bond with a chain aminoalkyl group. ]. The developer carrier according to claim 1, wherein each of the units independently has a structure represented by the following structural formula (2):

[In the structural formula (2),
R12 represents a hydrogen atom or a methyl group,
A1 represents a structure represented by the following structural formula (3),
**-R13-O-CONH-B1-NHCO-O*** Structural formula (3)
{In the structural formula (3), R13 represents a linear or branched alkylene group having 1 to 4 carbon atoms, and the symbol "**" is a bonding portion with a non-carbonyl oxygen atom of the unit. ,
The symbol “***” is a bond with any one selected from “*1”, “*2”, “*3” in the structural formula (1) and n “*4”. Yes,
B1 represents either the following structural formula (4) or structural formula (5),

(In the structural formula (4), the symbols “*B1” and “*B2” respectively represent the bonding portion with each nitrogen atom of the two urethane bonds in the structural formula (3),
In the structural formula (5), the symbols “*B3” and “*B4” respectively represent the bonding part with each nitrogen atom of the two urethane bonds in the structural formula (3). )}]. A process cartridge that can be attached to and detached from a main body of an electrophotographic apparatus,
At least a toner container containing a toner and a developer carrying body for carrying the toner, wherein the developer carrying body is the developer carrying body according to claim 1 or 2. Process cartridge. Electrophotographic photoreceptor,
An electrophotographic apparatus comprising at least a charging member arranged to charge the electrophotographic photosensitive member, and a developer carrying member for supplying toner to the electrophotographic photosensitive member,
An electrophotographic apparatus, wherein the developer carrying member is the developer carrying member according to claim 1 or 2.

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