JP5043395B2 - Developing roller and manufacturing method thereof, developing device and image forming apparatus - Google Patents

Description

  The present invention relates to a developing roller used in an electrophotographic image forming apparatus such as a copying machine or a laser printer, a manufacturing method thereof, a developing apparatus using the same, and an image forming apparatus.

  2. Description of the Related Art An electrophotographic image forming apparatus employing a pressure development method is known as an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile receiver. The pressure development method uses a non-magnetic one-component developer as the developer, attaches the developer to the latent image on the photosensitive drum, and visualizes the latent image, which eliminates the need for magnetic materials and simplifies and reduces the size. In addition to being easy to use, it is frequently used because it is easy to colorize the developer.

As shown in FIG. 3, an electrophotographic image forming apparatus employing such a pressure development method charges a photosensitive drum 21 rotated by a rotating mechanism and the photosensitive drum 21 arranged around the photosensitive drum 21. A charging member 22 is provided. Further, this electrophotographic image forming apparatus irradiates the photosensitive drum 21 with a laser beam 23 to discharge an electrostatic latent image corresponding to the image by discharging a portion other than the portion corresponding to the image or a portion corresponding to the image. An exposure apparatus is formed on the top. Further, the electrophotographic image forming apparatus includes a developing device 24 that supplies a developer to the electrostatic latent image formed on the photosensitive drum 21 and develops the developer, and transfers the developer adhered to the electrostatic latent image to a transfer member (recording material). It has a transfer roller 29 for transferring it upward. Further, the image forming apparatus includes a cleaning blade 30 that discharges and cleans the surface of the photosensitive drum 21 after transferring the developer, and a fixing device 32 that fixes the developer on the transfer body. The developing device 24 includes a developing roller 25, a developer supply roller 26 that applies the stored developer 28 to the surface of the developing roller 25, and a developer that is applied to the surface of the developing roller 25 in a more uniform thin layer. A developing blade 27 for adjusting is provided. The developing roller 25 supplies the developer made uniform by the developing blade to the photosensitive drum 21 and rotates while being in contact with or in proximity to the photosensitive drum 21, thereby causing the developer formed in a thin layer to become latent on the photosensitive drum 21. The latent image formed on the photosensitive drum 21 attached to the image is visualized.

  The developing roller used in this electrophotographic developing method can sufficiently withstand the heat generated when energized for a long time at a high voltage. In particular, the photosensitive member is not contaminated by the decomposition of the polymer member, and the electrical resistance of the member does not change. (Patent Document 1). Furthermore, the fluctuation range of the electric resistance increases due to changes in the environment such as temperature and humidity, and the image density may change greatly accordingly (Patent Document 2). Furthermore, if the developer supply roller and the developing roller are in contact with each other, the electrophotographic image forming apparatus may be kept in contact at the same position for a long period of time, for example, due to being left in a state where it is not operated for a long period of time. . In such a case, a component that exudes from the developer supply roller may adhere to the surface of the developing roller, resulting in banding in a halftone image or the like. In particular, this phenomenon can remarkably occur when left for a long period of time in an environment of high temperature and high humidity, for example, 40 ° C./95% RH.

Japanese Patent No. 3186541 Japanese Patent Laid-Open No. 7-13415

  An object of the present invention is to provide a developing roller having high reliability, a manufacturing method thereof, a developing device using the same, and an image forming apparatus.

（式中ｌは正の整数を示す。）

（式中ｍは正の整数を示す。）

（式中ｎは正の整数を示す。）。
本発明の一態様によれば、軸体と、
該軸体の周囲を被覆している弾性層とを具備している現像ローラであって、
下記（ａ）と、下記（ｂ）から（ｄ）又は下記（ｂ）及び（ｅ）を含むアルコール群との反応物からなるウレタン樹脂を表面層中に含み、かつ表面のエチレングリコールに対する接触角が６０．０度以上９０．０度以下であり、かつ、ジヨードメタンに対する接触角が３０．０度以上３８．０度以下であることを特徴とする現像ローラ：
（ａ）イソシアネート
（ｂ）下記式（１）で示されるユニットを含む第１のアルコール；
（ｃ）下記式（２）で示されるユニットを含む第２のアルコール；
（ｄ）下記式（３）で示されるユニットを含む第３のアルコール；
（ｅ）下記式（２）で示されるユニット及び下記式（３）で示されるユニットを含む第４のアルコール：

（式中ｌは正の整数を示す。）

（式中ｎは正の整数を示す。）

（式中ｎは正の整数を示す。）。
また本発明の他の態様によれば、上記の現像ローラの製造方法であって、
軸体又は弾性層の周囲を、上記（ａ）と、上記（ｂ）から（ｄ）又は上記（ｂ）及び（ｅ）とを含む組成物で被覆し、次いで該（ａ）と、（ｂ）から（ｄ）又は（ｂ）及び（ｅ）とを反応させて、エチレングリコールに対する接触角が６０．０度以上９０．０度以下であり、かつ、ジヨードメタンに対する接触角が３０．０度以上３８．０度以下の表面を有する表面層を形成する工程を有することを特徴とする現像ローラの製造方法が提供される。 In view of the above-mentioned problems, the present inventors have studied repeatedly to obtain a developing roller having a surface on which a component exuding from the developer supply roller is difficult to adhere. In the process, the present inventors considered that the surface free energy of the developing roller is the dominant factor of the adhesion of the exuding component. Therefore, the present inventors measured the contact angles of water, diiodomethane and ethylene glycol of a developing roller having a surface layer made of various polymer materials in order to calculate the surface free energy based on the theory of Kitazaki and Hata. . When the surface free energy was calculated using these contact angles, a clear relationship could not be found between the surface free energy value and the adhesion of the exuding component. That is, even with a developing roller having a surface layer with a low surface energy, the exuding component may adhere to the image, resulting in image defects. However, in the course of these experiments, the inventors have the following (a) and the following (b) to (d) or the following (b) and (e):
(A) Isocyanate (b) a first alcohol containing a unit represented by the following formula (1);
(C) a second alcohol containing a unit represented by the following formula (2);
(D) a third alcohol containing a unit represented by the following formula (3);
(E) A urethane resin obtained by reacting a unit represented by the following formula (2) and a fourth alcohol containing a unit represented by the following formula (3), and having a contact angle with respect to ethylene glycol of 60. A developing roller including a layer having a contact angle with respect to diiodomethane of not less than 0 ° and not more than 90.0 ° but not less than 30.0 ° and not more than 38.0 ° does not necessarily prevent adhesion of the exuding component. Although not obtained, it has been found that the occurrence of image defects due to the exuding component adhering to the surface, specifically the banding described above, can be greatly improved. The present invention has been made based on such novel findings.

(In the formula, l represents a positive integer.)

(In the formula, m represents a positive integer.)

(Wherein n represents a positive integer).
According to one aspect of the present invention, a shaft body;
A developing roller comprising an elastic layer covering the periphery of the shaft,
The surface layer contains a urethane resin made of a reaction product of the following (a) and the following (b) to (d) or an alcohol group including the following (b) and (e): A developing roller having a contact angle with respect to diiodomethane of 30.0 degrees or more and 38.0 degrees or less.
(A) Isocyanate (b) a first alcohol containing a unit represented by the following formula (1);
(C) a second alcohol containing a unit represented by the following formula (2);
(D) a third alcohol containing a unit represented by the following formula (3);
(E) a fourth alcohol containing a unit represented by the following formula (2) and a unit represented by the following formula (3):

(In the formula, l represents a positive integer.)

(In the formula, n represents a positive integer.)

(Wherein n represents a positive integer).
According to another aspect of the present invention, there is provided a method for manufacturing the above developing roller,
The periphery of the shaft body or the elastic layer is coated with a composition containing the above (a) and the above (b) to (d) or the above (b) and (e), and then the (a) and (b ) To (d) or (b) and (e), the contact angle with respect to ethylene glycol is 60.0 degrees or more and 90.0 degrees or less, and the contact angle with diiodomethane is 30.0 degrees or more. There is provided a developing roller manufacturing method comprising a step of forming a surface layer having a surface of 38.0 degrees or less.

According to one embodiment of the present invention, it is possible to obtain a developing roller that can stably provide a high-quality electrophotographic image.
According to another aspect of the present invention, an image forming apparatus that stably provides high-quality electrophotographic images can be obtained.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

[Development roller]
FIG. 1 shows a cross-sectional structure of an example of an embodiment of a developing roller according to the present invention. A developing roller 100 according to FIG. 1 has an elastic layer 2 as a surface layer on the outer periphery of a highly conductive shaft (shaft body) 1. The elastic layer 2 has a surface with a contact angle with respect to ethylene glycol of 60.0 degrees or more and 90.0 degrees or less and a contact angle with diiodomethane of 30.0 degrees or more and 38.0 degrees or less. The elastic layer 2 includes a urethane resin that is a reaction product of the following (a) and the following (b) to (d) or the following (b) and (e).
(A) Isocyanate (b) a first alcohol containing a unit represented by the following formula (1);
(C) a second alcohol containing a unit represented by the following formula (2);
(D) a third alcohol containing a unit represented by the following formula (3);
(E) a fourth alcohol containing a unit represented by the following formula (2) and a unit represented by the following formula (3):

（式中ｌは正の整数を示す。）

(In the formula, l represents a positive integer.)

（式中ｍは正の整数を示す。）

(In the formula, m represents a positive integer.)

（式中ｎは正の整数を示す。）。

(Wherein n represents a positive integer).

  As will be described later, the developing roller according to the present invention is a case where it is in contact with a developer supply roller having a foamed elastic layer containing a copolymer of silicone and polyether as a surface layer for a long period of time. The influence of the component exuded from the developer supply roller on the quality of the electrophotographic image can be extremely effectively suppressed. Further, by using such a developing roller, it is possible to provide an image forming apparatus capable of stably supplying a high-quality image.

  The urethane resin in the surface layer according to the present invention includes all of the units represented by the above formulas (1) to (3). The units represented by the above formula (1), formula (2), and formula (3) each finely control the van der Waals force and the like of the surface layer because the number of ether groups is different from the number of carbon atoms. It is speculated that it can be done.

  And in this invention, when using the said 1st-3rd alcohol for the synthesis | combination of a urethane resin, mass ratio (1st alcohol: 2nd alcohol: 3rd alcohol) of those alcohol groups is 100: It is preferable to be 3: 2 to 100: 25: 20. Furthermore, in this case, it is preferable that the first alcohol is an alcohol having two or more hydroxyl groups, and the second alcohol and the third alcohol are both alcohols having one hydroxyl group. The urethane resin thus obtained has a structure in which the units represented by the formulas (2) and (3) are bonded in a pendant manner to the polymer main chain. The surface layer containing such a urethane resin has a contact angle with respect to surface ethylene glycol of 60.0 degrees or more and 90.0 degrees or less, and a contact angle with diiodomethane of 30.0 degrees or more and 38.0 degrees or less. be able to.

Moreover, in this invention, when using the said 1st alcohol and 4th alcohol for the synthesis | combination of a urethane resin, mass ratio (1st alcohol: 4th alcohol) of those alcohol groups is 100: 5- 100: 40 is preferred. Furthermore, in this case, the first alcohol is preferably an alcohol having two or more hydroxyl groups, and the fourth alcohol is preferably an alcohol having one hydroxyl group. The urethane resin synthesized using such an alcohol has a structure in which the units represented by the formulas ( 2 ) and (3) are bonded in a pendant manner to the polymer main chain. The contact angle with respect to the surface ethylene glycol can be set to 60.0 degrees or more and 90.0 degrees or less, and the contact angle with diiodomethane can be set to 30.0 degrees or more and 38.0 degrees or less.

As described above, in the urethane resin in the surface layer of the developing roller according to the present invention, the alcohol group used as a raw material always includes all units represented by the above formulas (1), (2), and (3).

The example of said (a) which is a raw material of the urethane resin which concerns on this invention includes the following.
Tolylene diisocyanate (TDI); Diphenylmethane diisocyanate (MDI); Naphthalene diisocyanate (NDI); Tolidine diisocyanate (TODI); Hexamethylene diisocyanate (HDI); Isophorone diisocyanate (IPDI); Phenylene diisocyanate (PPDI); Xylylene diisocyanate (XDI) Tetramethylxylylene diisocyanate (TMXDI); cyclohexane diisocyanate and the like.

  Of these, aromatic isocyanates such as TDI, MDI, NDI, PPDI, XDI and TMXDI are preferred. In particular, MDI is preferable because it can improve the resilience of the developing roller after a local load.

The elastic layer as the surface layer may be composed only of the urethane resin described so far, but may contain other polymer components within the scope of the present invention. Examples of other polymer components include:
Natural rubber (NR); Butyl rubber (IIR); Nitrile rubber (NBR); Polyisoprene rubber (IR); Polybutadiene rubber (BR); Silicone rubber; Styrene-butadiene rubber (SBR); Ethylene-propylene rubber (EPM); -Propylene-diene rubber (EPDM); chloroprene rubber (CR); acrylic rubber (ACM); and mixtures thereof.

  Among these, silicone rubber and elastomers and resins such as EPDM are particularly preferable. In these elastomers or resins, the surface of the outermost elastic layer 2 has a contact angle with respect to ethylene glycol of 60.0 degrees or more and 90.0 degrees or less, and a contact angle with diiodomethane of 30.0 degrees or more and 38.38. Used in an amount in the range of 0 degrees or less.

The volume resistivity of the elastic layer 2 of the developing roller shown in FIG. 1 is preferably 10 ³ to 10 ¹⁰ Ωcm, more preferably 10 ⁴ to 10 ⁸ Ωcm.

  The hardness of the elastic layer 2 is preferably 25 to 60 degrees in terms of ASKER-C hardness. Furthermore, the elastic layer 2 preferably has a thickness of 0.3 mm to 10 mm, particularly 1.0 mm to 5.0 mm.

  Examples of the conductive substance used for imparting conductivity to the elastic layer 2 include an electron conductive substance and an ion conductive substance.

Examples of electronically conductive materials include:
-Conductive carbon such as ketjen black EC, acetylene black;
-Super Abrasion Furnace (SAF), Quasi Super Abrasion Furnace (Intermediate SAF (ISAF)), High Abrasion Furnace (HAF), Good Extrusion Furnace (Fast Extraction) Furnace (FEF)), General Purpose Furnace (GPF), Semi Reinforming Furnace (SRF)), Fine Thermal Decomposition (Fine Thermal (FT)), Medium Thermal Decomposition (Medium MT), etc. For carbon;
・ Color (ink) carbon that has undergone oxidation treatment;
-Metals such as copper, silver, germanium, and metal oxides.
Among these, carbon black (conductive carbon, carbon for rubber, carbon for color (ink), etc.) is preferable because the conductivity can be easily controlled with a small amount.

Examples of the ion conductive material include the following.
Inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate and lithium chloride; organic ionic conductive materials such as modified aliphatic dimethylammonium ethosulphate and stearylammonium acetate.

  The conductive material such as the electron conductive material and the ion conductive material is used in an amount necessary for making the elastic layer 2 have an appropriate volume resistivity as described above. Usually, it is used in the range of 0.5 to 50 parts by mass, preferably 1 to 30 parts by mass with respect to 100 parts by mass of the substrate.

(Surface roughness: Rzjis)
The surface roughness of the developing roller shown in FIG. 1 is Rzjis (according to Japanese Industrial Standards (JIS) B0601: 2001), and the electrophotographic photosensitive member may be in the range of 1 to 15 μm, particularly 3 to 10 μm. Is preferable for stably charging.

The surface roughness in the above range can be achieved, for example, by incorporating rough particles in the elastic layer 2. Examples of the roughening particles include the following.
Rubber particles such as EPDM, NBR, SBR, CR, and silicone rubber; Thermoplastic resin particles such as PMMA, polystyrene, polyolefin, and polyvinyl chloride; Elastomer particles such as polyurethane, polyester, and polyamide-based thermoplastic elastomer (TPE); Urethane Resin; Fluorine resin; Silicone resin; Phenol resin; Naphthalene resin; Furan resin; Xylene resin; Divinylbenzene polymer; Styrene-divinylbenzene copolymer; Resin particles such as polyacrylonitrile resin.
In addition, the above can be used alone or in combination.

(Shaft)
As the highly conductive shaft 1 in the developing roller shown in FIG. 1, any shaft can be used as long as it has good conductivity. Usually, the outer diameter 4 made of aluminum, iron, SUS or the like is used. A metal cylinder of 10 mm is used.

FIG. 2 is a schematic cross-sectional view showing another embodiment of the developing roller according to the present invention.
A developing roller 200 according to FIG. 2 includes a shaft body 1, an elastic layer 201 covering the periphery of the shaft body 1, and a resin layer 203 forming a surface layer covering the periphery of the elastic layer 201. . The resin layer 203 corresponds to the elastic layer 2 of the developing roller 100. Therefore, for the details of the resin layer 203, the description of the elastic layer 2 is used. However, the resin layer 203 is preferably a non-foamed, solid (solid) layer from the viewpoint of further improving the uniform chargeability of the toner.

In addition, an appropriate resistance region (volume resistivity) of the resin layer 203 is preferably 10 ³ to 10 ¹¹ Ωcm, more preferably 10 ⁴ to 10 ¹⁰ Ωcm.
Furthermore, the thickness of the resin layer 203 is more preferably in the range of 0.5 μm to 200 μm, particularly 1.0 μm to 100 μm.

Next, the elastic layer 201 contains an elastomer or other resin. The elastic layer 201 is preferably adjusted to a suitable resistance region (volume resistivity) by containing a conductive substance. The preferred volume resistivity is preferably 10 ³ to 10 ¹⁰ Ωcm, more preferably 10 ⁴ to 10 ⁸ Ωcm.
Furthermore, the hardness of the elastic layer 201 is preferably 25-60 degrees in terms of ASKER-C hardness.
Furthermore, the thickness of the elastic layer 201 is usually in the range of 0.3 mm to 10 mm, particularly 1.0 mm to 5.0 mm.

Examples of the elastomer or other resin include the following.
Natural rubber (NR); Butyl rubber (IIR); Nitrile rubber (NBR); Polyisoprene rubber (IR); Polybutadiene rubber (BR); Silicone rubber; Styrene-butadiene rubber (SBR); Ethylene-propylene rubber (EPM) Ethylene-propylene-diene rubber (EPDM); chloroprene rubber (CR); acrylic rubber (ACM), and mixtures thereof.
Among these, silicone rubber or EPDM (ethylene-propylene-diene rubber) is preferable.

  Examples of the conductive material include the same conductive materials that can be added to the elastic layer 2. The amount of addition is the same as in the case of the elastic layer 2.

  The thickness of the elastic layer and the resin layer of the developing roller according to the present invention is measured by cutting the roller on which the elastic layer and the resin layer are formed, and measuring the thickness of each layer in the cross section with a caliper or a video microscope. Can be obtained. For example, 9 points may be measured and the average value may be set as the thickness of each layer. When the thickness is thin like a resin layer, the cross section may be measured at 9 points using a video microscope (magnification 1000 to 3000 times), and the average value may be the layer thickness.

  The developing roller according to the present invention shown in FIGS. 1 and 2 can be manufactured as follows, for example.

  With respect to the developing roller shown in FIG. 1, for example, (a) and (b) to (d) above for forming the elastic layer 2 in a cavity of a molding die in which a shaft body is previously arranged. Or it can produce by inject | pouring the composition containing said (b) and (e). Further, from a slab or block separately formed using the above composition in advance, by cutting or the like, it is cut into a predetermined shape and dimensions such as a tube shape, and the shaft body is press-fitted into this to form the outermost layer on the shaft body. A developing roller can be produced by forming an elastic layer. If desired, the outer diameter may be further adjusted to a predetermined outer diameter by cutting or polishing treatment.

The developing roller shown in FIG. 2 is produced, for example, by applying the above composition onto the outer peripheral surface of the elastic layer 201 formed in advance on the outer periphery of the shaft body by a method such as spraying or dipping, and heat curing. be able to. The elastic layer 201 can be formed, for example, by the following method 1) or 2):
1) A method comprising a step of injecting a composition for forming the elastic layer into a cavity of a molding die in which a shaft is previously arranged and heat-curing;
2) A step of forming a slab or a block using a composition for forming an elastic layer in advance, and cutting the slab or block into a predetermined shape and size such as a tube by processing such as cutting, And press-fitting the body.

  In either case of the above methods 1) and 2), after forming the elastic layer 201 around the shaft body, it is further adjusted to a predetermined outer diameter by cutting or polishing treatment as necessary. Also good.

[Developer]
The developing device according to the present invention includes at least the developing roller according to the present invention as described above and a developer supply roller.

  The developing device according to the present invention is not particularly limited as long as it is a developing device provided in an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, or a printer. For example, a developing device (details will be described later) of an electrophotographic image forming apparatus such as a printer having the configuration shown in FIG.

  Next, the developer supply roller 26 according to the present invention shown in FIG. 3 will be described in detail.

  The developer supply roller includes a cored bar (shaft body) and a foamed elastic layer formed around the cored bar. The foamed elastic layer preferably contains a copolymer of silicone and polyether.

Moreover, the example of the foaming elastic body used for a foaming elastic layer contains the following.
Rubber raw materials such as polyurethane, nitrile rubber, ethylene propylene rubber, ethylene propylene diene rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, silicone rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber; or these rubber raw materials A foamed elastic body or the like obtained using a monomer or the like that is a manufacturing raw material (these monomers may also be referred to as a rubber raw material).

  The foamed elastic body obtained by using the rubber raw material alone or a rubber raw material combining two or more of these rubber raw materials may be used. Among these foamed elastic bodies, polyurethane foam is preferably used.

As the polyol component constituting the raw material for forming the polyurethane foam, any of known polyols such as polyether polyol, polyester polyol, and polymer polyol, which are generally used for producing flexible polyurethane foam, can be used. Moreover, as a polyisocyanate component which comprises the raw material for forming a polyurethane foam, well-known at least bifunctional or more polyisocyanate is used.
Examples of the polyisocyanate include the following.
2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; orthotoluidine diisocyanate; naphthylene diisocyanate; xylylene diisocyanate; 4,4'-diphenylmethane diisocyanate; carbodiimide modified MDI; polymethylene polyphenyl isocyanate; .
These may be used alone or in combination.

  The polyurethane foam raw material in which these polyol component and polyisocyanate component are blended preferably contains a copolymer of silicone and polyether. Although this component plays a role as a foam stabilizer, there are no particular restrictions on both the silicone part and the polyether part, and known materials are preferably used.

  Furthermore, crosslinking agents, foaming agents (water, low-boiling substances, gas bodies, etc.), surfactants, catalysts, conductivity-imparting agents for imparting desired conductivity, antistatic agents, and the like can be added. .

  The manufacturing method of the developer supply roller is not particularly limited, and a suitable method may be selected from known manufacturing methods and manufactured. Specifically, it is produced by forming a foamed elastic layer by coating a cored bar made of a metal material such as iron or stainless steel, usually having a diameter of 4 to 10 mm and a length of 200 to 400 mm, with a foamed elastic body. can do. The outer diameter of the developer supply roller is not particularly limited, and may have various outer diameters depending on the purpose, but is generally 10 to 20 mm.

For example, first, a polyurethane raw material composition is prepared by uniformly mixing various materials used for forming the foamed elastic layer. Next, a developer supply roller can be produced by using the raw material composition and the following method 1) or 2).
1) A core metal is poured into a cavity of a molding die provided in advance and heated to cause reaction hardening or solidification. Thus, the foamed elastic layer is integrally formed and manufactured.
2) A foamed elastic slab or block is formed in advance using the polyurethane raw material composition. Cut into a predetermined shape and dimensions such as a tube by cutting the slab or block. A mandrel is press-fitted into the mandrel and a foamed elastic layer is coated on the mandrel.
Moreover, the method etc. which combined these methods suitably can also be mentioned. If desired, the outer diameter may be further adjusted to a predetermined outer diameter by cutting or polishing treatment.

[Image forming apparatus]
An image forming apparatus according to the present invention includes an image carrier for carrying an electrostatic latent image, a charging device for primarily charging the image carrier, and an electrostatic latent image on the primary charged image carrier. It has an exposure apparatus for forming. Further, the image forming apparatus includes a developing device for developing the electrostatic latent image with a developer to form a developer image, and a transfer device for transferring the developer image to a transfer material. The image forming apparatus according to the present invention includes a developing device having the developing roller according to the present invention.

FIG. 3 is a cross-sectional view showing a schematic configuration of an embodiment of the image forming apparatus of the present invention.
The photosensitive drum 21 as an image carrier rotates in the direction of arrow A and is uniformly charged by a charging member 22 as a charging device for charging the photosensitive drum 21. An electrostatic latent image is formed on the surface of the photosensitive drum 21 by a laser beam 23 from an exposure device that writes the electrostatic latent image on the photosensitive drum 21. The electrostatic latent image is developed by applying a developer 28 by a developing device 24 held in a process cartridge that is detachable from the image forming apparatus main body, and visualized as a developer image.

  Development is so-called reversal development in which a developer image is formed in the exposed portion. The visualized developer image on the photosensitive drum 21 is transferred to a paper 33 as a transfer material by a transfer roller 29 as a transfer device. The paper 33 to which the developer image has been transferred is fixed by the fixing device 32, discharged outside the device, and the printing operation is completed.

  On the other hand, the untransferred developer remaining on the photosensitive drum 21 without being transferred is scraped off by a cleaning blade 30 as a cleaning member for cleaning the surface of the photosensitive drum and stored in a waste developer container 31. The cleaned photosensitive drum 21 repeats the above operation.

  The developing device 24 includes a developing container 34 that contains a non-magnetic developer 28 as a one-component developer, and a developer carrying member that is positioned in an opening extending in the longitudinal direction in the developing container 34 and is opposed to the photosensitive drum 21. And a developing roller 25 as a body. The developing device 24 is arranged to develop and visualize the electrostatic latent image on the photosensitive drum 21. The electrophotographic process cartridge includes a developing device 24 and at least one of an image carrier 21, a charging member 22, a cleaning blade 30, and a transfer roller 29, and these are integrally held, and It is detachably provided on the forming apparatus.

  The developing roller 25 is in contact with the photosensitive drum 21 with a contact width. In the developing device 24, the developer supply roller 26 contacts the upstream side in the rotation direction of the developing roller 25 with respect to the contact portion of the developing blade 27, which is a developer regulating member, with the surface of the developing roller 25 in the developing container 34. And is rotatably supported.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, a present Example does not limit this invention at all.

In this example, the following alcohol was used.
<Alcohol (1)>
The following raw materials were prepared.
・ 100 parts by mass of polytetramethylene ether glycol (trade name: PTG1000SN; manufactured by Hodogaya Chemical Co., Ltd.)
・ Isocyanate 18.7 parts by mass (trade name: Millionate MT; manufactured by Nippon Polyurethane Industry Co., Ltd.)
These raw materials are mixed stepwise with methyl ethyl ketone (MEK) and reacted at 80 ° C. for 3 hours under a nitrogen atmosphere to obtain a bifunctional polyether diol prepolymer (polyether diol having a unit represented by Formula 1 ( BO)) was obtained. The obtained polyether diol prepolymer had a weight average molecular weight Mw = 10000 and a hydroxyl value of 18.2 (mgKOH / g). This was used as alcohol (1).

<Alcohol (2)>
・ 100 parts by mass of polytetramethylene glycol (trade name: PTG650SN; manufactured by Hodogaya Chemical Co., Ltd.)
・ Trimethylolpropane 3 parts by mass (Mitsubishi Gas Chemical Co., Ltd.)
・ Isophorone diisocyanate (IPDI) 30 parts by mass (manufactured by Aldrich)
These raw materials are stepwise mixed with methyl ethyl ketone (MEK) and reacted at 80 ° C. for 3 hours under a nitrogen atmosphere to obtain a polyether diol prepolymer (polyether diol (BO) having a unit represented by Formula 1). Got. The obtained polyether diol prepolymer had a weight average molecular weight Mw = 6800 and a hydroxyl value of 43 (mgKOH / g). This was used as alcohol (2).

<Alcohol (3)>
LB385 (manufactured by Sanyo Chemical Industries; monofunctional, polyether alcohol (PO) having a unit represented by Formula 2) was used as the alcohol (3).

<Alcohol (4)>
G100 (manufactured by Mitsui Takeda Chemical Company; trifunctional, polyether triol (PO) having a unit represented by Formula 2) was used as the alcohol (4).

<Alcohol (5)>
Poly (ethylglycyl) methyl ether (PEME) (manufactured by Aldrich; monofunctional polyether alcohol (EO) having a unit represented by Formula 3) was used as the alcohol (5).

<Alcohol (6)>
HB260 (manufactured by Sanyo Chemical Industries; monofunctional, polyether alcohol (PO-EO) having units represented by formulas 2 and 3 at the same time) was used as alcohol (6).

Example 1
A core metal (shaft) having an outer diameter of 8 mm is placed concentrically in a cylindrical mold having an inner diameter of 16 mm, and liquid conductive silicone rubber (ASKER-, manufactured by Toray Dow Corning Silicone Co., Ltd.) is used as a material for forming an elastic layer. C hardness 45 degrees, volume resistivity 1 × 10 ⁷ Ω · cm product) was injected. After pouring, the mold is placed in an oven at 130 ° C. and heated for 20 minutes, demolded, and further subjected to secondary vulcanization in an oven at 200 ° C. for 4 hours to form an elastic layer 201 having a thickness of 4 mm on the outer periphery of the core metal. Formed on the surface.
Next, the following raw material mixture was prepared.
Alcohol (1) 100 parts by weight Alcohol (3) 3.1 parts by weight Alcohol (5) 2 parts by weight Isocyanate C2521 125 parts by weight (solid content 65% by Nippon Polyurethane Industry)
Methyl ethyl ketone (MEK) was added to this raw material mixture to adjust the solid content to 25 to 30% by mass, and this was used as a raw material solution for resin layer formation. 20 parts by mass of carbon black MA230 (manufactured by Mitsubishi Chemical Co., Ltd.) and 15 parts by mass of acrylic particles MX-1000 (manufactured by Soken Chemical Co., Ltd.) are added to 100 parts by mass of the solid content of the raw material liquid, and the coating liquid is stirred with a ball mill. Disperse to prepare a paint. The obtained paint is applied by dipping on the previously molded elastic layer, dried in an oven at 80 ° C. for 15 minutes, and then cured in an oven at 140 ° C. for 4 hours to form a resin layer 203 having a layer thickness of 15 μm. A developing roller was obtained.

(Examples 2 to 9, Comparative Examples 1 and 2)
A developing roller was prepared in the same manner as in Example 1 except that the blending of alcohol and isocyanate used for preparation of the raw material liquid for resin layer molding was changed as shown in Table 1 below.

<Production of developer supply roller>
Next, an example of producing a developer supply roller that can be used in the present invention is shown below.
The following were mixed beforehand.
90 parts by weight of FA908 (manufactured by Sanyo Chemical Industries; trade name, polyol)
10 parts by mass of POP34-28 (manufactured by Sanyo Chemical Industries; trade name, polyol)
TOYOCAT-ET 0.1 part by mass (manufactured by Tosoh Corporation; trade name, tertiary amine catalyst)
TOYOCAT-L33 0.5 part by mass (made by Tosoh Corporation; trade name, tertiary amine catalyst)
Water (foaming agent) 2.5 parts by mass SH190 1 part by mass (manufactured by Toray Dow Corning Silicone; trade name, copolymer of silicone and polyether)
Thereafter, 24 parts by mass of Coronate 1021 (manufactured by Nippon Polyurethane Industry Co., Ltd .; trade name, NCO% = 45) as a polyisocyanate was added to this mixture and mixed and stirred. Next, the foamed elastic layer made of polyurethane sponge having a thickness of 4.5 mm is integrally formed around the core metal having an outer diameter of 5 mm by foam molding using the same mold as that used in Example 1 above. A developer supply roller was formed.

<Measurement of contact angle>
A contact angle meter CA-S ROLL (trade name) manufactured by Kyowa Interface Chemical Co., Ltd. was used. The injection needle of the dropping solution was a 15 gauge manufactured by Kyowa Interface Science Co., Ltd. The liquid diameter in the droplet dropping direction was about 1.5 mm. In a room temperature and normal humidity environment (23 ° C./65% RH), 10 points were dropped per surface of the developing roller image area, and the contact angle after 10 seconds was measured. The average value of eight contact angles excluding one of the maximum value and the minimum value of the 10 contact angles was rounded off. The ethylene glycol and diiodomethane to be added dropwise were those manufactured by Aldrich.

<Measurement of Rzjis>
For measurement of the surface roughness Rzjis, a contact-type surface roughness meter (manufactured by Kosaka Laboratory Ltd .: Surfcorder-SE-3300) was used. The measurement conditions were set such that the cutoff value was 0.8 mm, the measurement length was 2.5 mm, the feed speed was 0.1 mm / second, and the magnification was 5000 times. As the number of measurement points, the surface of the developing roller in the development area was arbitrarily measured at 10 points, and the average value was obtained. The results of Rzjis for each roller are shown in Table 2.

<Measurement of Asker-C hardness>
Asker-C hardness is measured according to a rubber material hardness measurement method. Specifically, an Asker rubber hardness meter (polymer) is used by using a test piece separately prepared according to the standard standard Asker C-type SRIS (Japan Rubber Association Standard) 0101. Measured with an instrument). The results of Asker-C hardness of each roller are shown in Table 2.

<Measurement of conductivity>
The electric resistance of the developing roller was measured using an electric resistance measuring machine shown in FIG. A load of 500 g was applied to both ends of the metal core of the developing roller 501 (arrow A in FIG. 4), pressed against the metal drum 53, and a voltage of 50 V was applied from the power supply 50 while rotating at a roller rotation speed of 1 rps. At this time, the voltage applied to the resistor 51 (10 kΩ) indicated by the voltmeter 52 was read for 30 seconds, and the roller electrical resistance value was obtained from the average value. The results of measuring the electrical resistance of each roller are shown in Table 2.

<Image evaluation>
(Development roller, developer supply roller contact part banding evaluation)
The developing roller and developer supply roller were mounted on an electrophotographic process cartridge, and the cartridge was left in a high temperature and high humidity environment (40 ° C./95 RH) for 30 days. Thereafter, the image was actually printed with a color laser printer (trade name: LBP5500, manufactured by Canon Inc.) and image evaluation was performed. As the developer, a magenta developer having a number average particle diameter of 7.0 μm was used. The number average particle size of the developer was calculated from the number distribution measured using a laser diffraction type particle size distribution meter (Coulter LS-130 type particle size distribution meter (manufactured by Coulter; trade name)).
The obtained image was visually observed, and banding in the halftone image was evaluated according to the following criteria.
A: Banding is not recognized B: Extremely slight banding is recognized to be practically acceptable C: Banding is recognized

The evaluation results are summarized in Table 3.
As is apparent from the comparison of the results of Examples 1 to 9 and Comparative Examples 1 and 2 shown in Table 3, the developing rollers of Examples 1 to 9 have a contact angle with respect to ethylene glycol of the surface of 60.0 degrees or more. The contact angle with respect to diiodomethane was 30.0 degrees or more and 38.0 degrees or less. When these developing rollers were used, a high-quality image free from banding could be obtained in a halftone image even if it contacted for a long time at the same position as the developer supply roller.

It is a schematic sectional drawing of the axial direction which shows the one aspect | mode of the developing roller which concerns on this invention. It is a schematic sectional drawing of the axial direction which shows the other aspect of the developing roller which concerns on this invention. 1 is a cross-sectional view illustrating an example of an electrophotographic image forming apparatus using a developing device according to the present invention. It is explanatory drawing of the measuring method of the electrical resistance of the developing roller which concerns on this invention.

Explanation of symbols

1: Good conductive shaft (shaft)
2: elastic layer 21: photosensitive drum 22: charging member 23: laser beam 24: developing device 25: developing roller 26: developer supply roller 27: developing blade 28: developer 29: transfer roller 30: cleaning blade 31: waste development Agent container 32: Fixing device 33: Paper 34: Developing container 50: Power source 51: Resistance 52: Voltmeter 53: Metal drum 100: Developing roller 200: Developing roller 201: Elastic layer 203: Resin layer

Claims (12)

A shaft body;
A developing roller comprising an elastic layer covering the periphery of the shaft,
The surface layer contains a urethane resin comprising a reaction product of the following (a) and the following (b) to (d) or an alcohol group including the following (b) and (e):
A developing roller having a contact angle with respect to ethylene glycol of the surface of 60.0 degrees or more and 90.0 degrees or less and a contact angle with diiodomethane of 30.0 degrees or more and 38.0 degrees or less:
(A) Isocyanate (b) a first alcohol containing a unit represented by the following formula (1);
(C) a second alcohol containing a unit represented by the following formula (2);
(D) a third alcohol containing a unit represented by the following formula (3);
(E) a fourth alcohol containing a unit represented by the following formula (2) and a unit represented by the following formula (3):

(In the formula, l represents a positive integer.)

(In the formula, m represents a positive integer.)

(Wherein n represents a positive integer). The developing roller according to claim 1, wherein a mass ratio of the alcohol group (first alcohol: second alcohol: third alcohol) is 100: 3: 2 to 100: 25: 20 . The developing roller according to claim 1 , wherein a mass ratio (first alcohol: fourth alcohol) of the alcohol group is 100: 5 to 100: 40 . The developing roller according to any one of claims 1 to 3 wherein the (b) having two or more hydroxyl groups. Wherein (c) is, the developing roller according to any one of claims 1 to 4 having one hydroxyl group. The developing roller according to any one of claims 1 to 5 wherein (d) has one hydroxyl group. The developing roller according to any one of claims 1 to 6 wherein (e) has one hydroxyl group. It is a manufacturing method of the developing roller according to claim 1,
The periphery of the shaft body or the elastic layer is coated with a composition containing the following (a) and the following (b) to (d) or the following (b) and (e), and then the (a) and (b ) To (d) or (b) and (e), the contact angle with respect to ethylene glycol is 60.0 degrees or more and 90.0 degrees or less, and the contact angle with diiodomethane is 30.0 degrees or more. A method for producing a developing roller, comprising a step of forming a surface layer having a surface of 38.0 degrees or less:
(A) Isocyanate (b) a first alcohol containing a unit represented by the following formula (1);
(C) a second alcohol containing a unit represented by the following formula (2);
(D) a third alcohol containing a unit represented by the following formula (3);
(E) a fourth alcohol containing a unit represented by the following formula (2) and a unit represented by the following formula (3):

(In the formula, l represents a positive integer.)

(In the formula, m represents a positive integer.)

(Wherein n represents a positive integer). Wherein (b) is two or more hydroxyl groups, wherein (c) is one hydroxyl group, wherein (d) is one and the hydroxyl group (e) is as defined in claim 8 is an alcohol having one hydroxyl group A method for manufacturing a developing roller. Developing roller and the developing device characterized in that it comprises at least a developer supply roller according to any one of claims 1 to 7. The developer supply roller includes a cored bar and a foamed elastic layer formed around the cored bar, and the foamed elastic layer contains a copolymer of silicone and polyether. Development device. An image carrier for carrying an electrostatic latent image; a charging device for primarily charging the image carrier; an exposure device for forming an electrostatic latent image on the primary charged image carrier; In an image forming apparatus having a developing device for developing an electrostatic latent image with a developer to form a developer image and a transfer device for transferring the developer image to a transfer material, the developing device includes: An image forming apparatus comprising the developing device according to claim 10.

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