JP2008292568A - Image forming device and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of an abnormal image such as scumming, image blurring, or image deletion caused by unevenness of various characteristics of the surface of a photoreceptor. <P>SOLUTION: In this image forming device, a protectant at least including a long-chain alkylamide compound having a dialkylamine previously expressed by formula (1) is imparted on the surface of the photoreceptor. In the formula (1), R<SP>1</SP>expresses an 8-20C alkyl group; R<SP>2</SP>and R<SP>3</SP>each express a 1-6C alkyl group; and n expresses an integer ≥1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method capable of stably forming a high-definition image.

  In recent years, an image forming apparatus using an electrophotographic method has been widely used for full-color image formation, and high speed, high image quality, energy saving, and space saving are regarded as important as basic specifications of the image forming apparatus. ing. In the case of full-color image formation, the image quality is particularly important, and it is required that a high-resolution image can be output stably.

  In order to perform full-color image formation at high speed, a method called a tandem method that forms images by arranging four image forming stations of cyan (C), magenta (M), yellow (Y), and black (Bk) side by side is advantageous. Yes, it is widely used. However, this tandem method has a drawback that the image forming apparatus becomes large. Therefore, a design that effectively uses the space in the image forming apparatus has been devised, and a contrivance has been made to reduce the number of parts as much as possible. Under such circumstances, a roller charging method is widely used in a charging process which is one of electrophotographic processes. In this roller charging method, charging is performed by bringing a charging roller and a photosensitive member into contact or close to each other and discharging between minute gaps. Ozone and ozone which are less harmful to the environment than the conventional non-contact type corona charging method are used. The amount of nitrogen oxides generated is small, which is advantageous from the environmental point of view, and it is not necessary to install an apparatus for removing the generated gas.

However, the roller charging method has various effects on a photoconductor (hereinafter also referred to as an electrophotographic photoconductor or an electrostatic latent image carrier), and it is difficult to stably output an image for a long period of time. There is. In the roller charging method, a direct current or a direct current voltage superimposed on an alternating current is applied to a charging member having a resistance of about 10 ² Ω / cm to ^{10 10} Ω / cm to the photosensitive member, and the photosensitive member is brought into contact with or close to the photosensitive member. , A method of imparting electric charge. Since this charging method is performed by discharging from the charging member to the member to be charged in accordance with Paschen's law, charging is started by applying a voltage higher than a certain threshold voltage. For this reason, compared with the corona charging method, the roller charging method has a lower voltage applied to the charging member, but is accompanied by discharge, so that the material on the surface of the photoconductor is cut by the discharge and easily wears. There is a problem that the surface of the photoreceptor becomes hydrophilic and image defects such as image flow are likely to occur. In order to solve these problems, a method of forming an image while applying a protective material to the surface of the photoreceptor is effective. This is because the protective material sacrifices discharge and protects the photoreceptor.

As a protective material for covering and protecting such a photoreceptor surface, for example, paraffin having an electric resistance of 10 ¹⁴ Ωcm or more, a relative dielectric constant of 1.5 to 4 and a melting point of 55 ° C. or more (see Patent Document 1), Long chain fatty acid metal salts (see Patent Document 2), long chain alkyl group-containing urea compounds (see Patent Document 3), and the like have been proposed. These are used for the purpose of reducing the coefficient of friction on the surface of the photoreceptor and improving the blade cleaning property of the toner, and for the purpose of preventing the surface of the photoreceptor from being hydrophilized by ozone and nitrogen oxides generated by corona charging. .
When these protective materials are applied to an image forming apparatus using a roller charging method, the protective effect of the photosensitive member against electric discharge is improved, but the protective material itself is altered by electric discharge, and the altered protective material becomes the photosensitive member. There is a problem in that it remains unremoved from the surface, causes non-uniformity of various characteristics on the surface of the photoreceptor, and an abnormal image is generated.

  In addition, the electrophotographic image forming apparatus is a high-speed information that can cope with diversification of information processing, such as copying machines, printers, facsimiles, multifunction machines having these functions, and printing machines. Increasing demand for recording devices. Therefore, the image forming apparatus is required to further increase the image forming speed, reduce the size, and reduce the cost, and it is necessary to increase the durability of the image forming member. Among these, it is desired to improve the durability of a photoreceptor, which is one of main image forming members.

As the photoconductor, (1) a thin film of amorphous silicon, Se, As ₂ Se ₃ , SeTe or the like that is photoconductive and highly electrically insulating on a conductive support is formed by vacuum evaporation, sputtering, Inorganic photoreceptors formed by reactive vapor deposition, etc. (2) Polyphyrin compounds such as phthalocyanine; Polycyclic condensed compounds such as quinacridone; Charge generating substances such as squaric compounds and azo compound pigments, hydrazone compounds, and phenylstilpenes There is an organic photoreceptor (OPC photoreceptor) in which a photosensitive layer formed of a charge transporting substance such as a compound or a benzidine compound and an insulating resin such as a polycarbonate resin is provided on a conductive support.
The photosensitive layer has a single layer type in which a charge generation material and a charge transport material are dispersed together in an insulating resin, and a transport material is dispersed in the insulation resin on the charge generation layer containing the charge generation material. Or a laminated type in which a dissolved charge transport layer is laminated.
The OPC photoreceptor is widely used because it is less expensive to manufacture than the inorganic photoreceptor and has advantages such as non-pollution.

Further, as a charging unit, a transfer unit, and a charge eliminating unit provided around the photoconductor, a corona discharge unit that generates a charge by applying a high voltage to a conductive wire to generate a corona discharge has been conventionally used. It was done. In recent years, a contact charging system in which a voltage is applied to a conductive roller that is in direct contact with a photosensitive member for charging is widely used. Compared with the non-contact type corona charging method, this contact method produces less ozone and nitrogen oxides which are bad for the environment, and is advantageous in terms of environment, and it is not necessary to install a device for removing generated gas.
However, in the contact method using the conductive roller in the charging unit, transfer unit, and neutralization unit, the protective material on the surface of the photosensitive member itself is altered by discharge, and the altered protective material remains on the photosensitive member surface without being removed. There is a problem that nonuniformity of various characteristics is caused on the body surface, and abnormal images such as background smudge, image blur, and image flow are generated.

  Therefore, it is possible to prevent the occurrence of abnormal images such as scumming, image blur, and image flow caused by non-uniformity of various characteristics of the photoreceptor surface, and image formation that can stably output high-quality images over a long period of time. At present, the apparatus and the image forming method are not yet provided.

JP-A-5-210338 Japanese Patent Laid-Open No. 1-167847 JP 2000-147819 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, according to the present invention, even in a contact charging type image forming apparatus using a roller charging type, abnormal images such as background stains, image blurring, and image flow caused by non-uniformity of various characteristics of the surface of the photosensitive member. An object of the present invention is to provide an image forming apparatus and an image forming method capable of preventing occurrence and stably outputting a high-quality image over a long period of time.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, a photoconductor caused by roller charging by attaching a protective agent containing a long-chain alkylamide compound having a dialkylamine to the surface of the photoconductor Reduces abnormal images due to non-uniformity of various characteristics of the surface, suppresses the reduction in resistance of the surface of the photoconductor in a high-temperature and high-humidity environment, and prevents the occurrence of abnormal images such as dirt, image blurring, and image flow. I found out.

ただし、前記一般式（１）中、Ｒ^１は、炭素数８〜２０のアルキル基を表す。Ｒ^２及びＲ^３は、それぞれ炭素数１〜６のアルキル基を表す。ｎは１以上の整数を表す。
＜２＞ 一般式（１）で表されるジアルキルアミンを有する長鎖アルキルアミド化合物を少なくとも含む保護剤を感光体の表面に付着する保護剤付着手段を有する前記＜１＞に記載の画像形成装置である。
＜３＞ 一般式（１）で表されるジアルキルアミンを有する長鎖アルキルアミド化合物の融点が、５５℃以上である前記＜１＞から＜２＞のいずれかに記載の画像形成装置である。
＜４＞ 保護剤が、更にＮ−ブチル−Ｎ’−ステアリル尿素及びステアリン酸亜鉛の少なくともいずれかを含有する前記＜１＞から＜３＞のいずれかに記載の画像形成装置である。
＜５＞ 帯電手段が、感光体と接触乃至近接させて帯電させるローラ帯電方式である前記＜１＞から＜４＞のいずれかに記載の画像形成装置である。
＜６＞ 感光体表面を帯電させる帯電工程と、帯電された感光体表面を露光して静電潜像を形成する露光工程と、前記静電潜像をトナーを用いて現像して可視像を形成する現像工程と、前記可視像を記録媒体に転写する転写工程と、前記記録媒体に転写された転写像を定着させる定着工程とを少なくとも含む画像形成方法であって、
前記感光体として、表面に、予め下記一般式（１）で表されるジアルキルアミンを有する長鎖アルキルアミド化合物を少なくとも含む保護剤が付着されている感光体を用いることを特徴とする画像形成方法である。

ただし、前記一般式（１）中、Ｒ^１は、炭素数８〜２０のアルキル基を表す。Ｒ^２及びＲ^３は、それぞれ炭素数１〜６のアルキル基を表す。ｎは１以上の整数を表す。
＜７＞ 一般式（１）で表されるジアルキルアミンを有する長鎖アルキルアミド化合物を少なくとも含む保護剤を感光体の表面に付着する保護剤付着工程を含む前記＜６＞に記載の画像形成方法である。
＜８＞ 一般式（１）で表されるジアルキルアミンを有する長鎖アルキルアミド化合物の融点が、５５℃以上である前記＜６＞から＜７＞のいずれかに記載の画像形成方法である。
＜９＞ 保護剤が、更にＮ−ブチル−Ｎ’−ステアリル尿素及びステアリン酸亜鉛の少なくともいずれかを含有する前記＜６＞から＜８＞のいずれかに記載の画像形成方法である。
＜１０＞ 帯電工程が、感光体と接触乃至近接させて帯電させるローラ帯電方式で行われる前記＜６＞から＜９＞のいずれかに記載の画像形成方法である。 The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A photosensitive member, a charging unit that charges the surface of the photosensitive member, an exposure unit that exposes the charged surface of the photosensitive member to form an electrostatic latent image, and develops the electrostatic latent image using toner. An image forming apparatus including at least a developing unit that forms a visible image, a transfer unit that transfers the visible image to a recording medium, and a fixing unit that fixes the transferred image transferred to the recording medium. ,
The image forming apparatus is characterized in that a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the following general formula (1) is attached to the surface of the photoreceptor.

In the general formula (1), ^{R 1} represents an alkyl group having 8 to 20 carbon atoms. R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 or more.
<2> The image forming apparatus according to <1>, further including a protective agent attaching unit that attaches a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) to the surface of the photoreceptor. It is.
<3> The image forming apparatus according to any one of <1> to <2>, wherein the long-chain alkylamide compound having a dialkylamine represented by the general formula (1) has a melting point of 55 ° C. or higher.
<4> The image forming apparatus according to any one of <1> to <3>, wherein the protective agent further contains at least one of N-butyl-N′-stearyl urea and zinc stearate.
<5> The image forming apparatus according to any one of <1> to <4>, wherein the charging unit is a roller charging method in which charging is performed in contact with or close to the photosensitive member.
<6> A charging step for charging the surface of the photoconductor, an exposure step for exposing the charged surface of the photoconductor to form an electrostatic latent image, and developing the electrostatic latent image with toner to form a visible image An image forming method comprising at least a developing step for forming the image, a transfer step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium,
An image forming method comprising using, as the photoreceptor, a photoreceptor on which a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the following general formula (1) is attached in advance: It is.

In the general formula (1), ^{R 1} represents an alkyl group having 8 to 20 carbon atoms. R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 or more.
<7> The image forming method according to <6>, further including a protective agent attaching step of attaching a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) to the surface of the photoreceptor. It is.
<8> The image forming method according to any one of <6> to <7>, wherein the long-chain alkylamide compound having a dialkylamine represented by the general formula (1) has a melting point of 55 ° C. or higher.
<9> The image forming method according to any one of <6> to <8>, wherein the protective agent further contains at least one of N-butyl-N′-stearyl urea and zinc stearate.
<10> The image forming method according to any one of <6> to <9>, wherein the charging step is performed by a roller charging method in which charging is performed in contact with or in proximity to the photoreceptor.

In the image forming apparatus of the present invention, a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) is previously attached to the surface of the photoreceptor.
The reason why the occurrence of abnormal images can be prevented by attaching a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) to the surface of the photoreceptor in advance is unknown. It is conceivable that the amide structure portion has the same effect of imparting lubricity as the conventional fatty acid metal salt and the like and the effect of suppressing the reaction with the oxidizing gas generated by charging. In addition, it is considered that the acidic substance generated by the discharge can be neutralized with the basic group of the dialkylamine structure, and the reduction in resistance due to the acidic substance can greatly contribute.
That is, the long-chain alkylamide compound having a dialkylamine represented by the general formula (1) is a compound having a long-chain alkyl group added with a tertiary amine type basic substance, and generally a hair rinse agent or the like. Since it is used in this material, it has the effect of improving the slipperiness even on the surface of the photoreceptor and reducing the wear caused by rubbing with the contact member.
In addition, the addition of a basic substance such as a tertiary amino group has the effect of neutralizing acidic substances such as nitrogen oxides, can reduce the generation of low-resistance substances, and is a long-chain alkyl having a dialkylamine The protective agent containing at least the amide compound can reduce the cause of nonuniformity of various characteristics on the surface of the photoreceptor.
Therefore, according to the image forming apparatus and the image forming method of the present invention, even in the contact charging type image forming apparatus using the roller charging method, the background stains and the images caused by the non-uniformity of various characteristics of the surface of the photosensitive member. Generation of abnormal images such as blurring and image flow can be prevented, and high-quality images can be output stably over a long period of time.

  According to the present invention, conventional problems can be solved, and even in a contact charging type image forming apparatus using a roller charging method, background smudges and images resulting from non-uniformity of various characteristics of the surface of the photoreceptor. It is possible to provide an image forming apparatus and an image forming method that can prevent occurrence of abnormal images such as blurring and image flow and can stably output high-quality images over a long period of time.

(Image forming apparatus and image forming method)
The image forming apparatus according to the present invention includes at least a photosensitive member, a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit, a cleaning unit, and other components appropriately selected as necessary. For example, static elimination means, recycling means, control means and the like. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit.
The image forming method of the present invention includes at least a charging step, an exposure step, a development step, a transfer step, and a fixing step, and a cleaning step, and other steps appropriately selected as necessary, for example, It includes a static elimination process, a recycling process, a control process, and the like. The charging process and the exposure process may be collectively referred to as an electrostatic latent image forming process.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the charging step can be performed by the charging unit, the exposure step can be performed by the exposing unit, The developing step can be performed by the developing unit, the transferring step can be performed by the transferring unit, the fixing step can be performed by the fixing unit, and the cleaning step can be performed by the cleaning unit. The other steps can be performed by the other means.

-Protective agent-
In the present invention, a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the following general formula (1) is previously attached to the surface of the photoreceptor.

In the general formula (1), R ¹ represents an alkyl group having 8 to 20 carbon atoms, for example, CH ₃ (CH ₂ ) ₈ , CH ₃ (CH ₂ ) ₉ , CH ₃ (CH ₂ ) ₁₀ , CH ₃ (CH ₂ ) ₁₁ , CH ₃ (CH ₂ ) ₁₂ , CH ₃ (CH ₂ ) ₈ , CH ₃ (CH ₂ ) ₁₃ , CH ₃ (CH ₂ ) ₁₄ , CH ₃ (CH ₂ ) ₁₅ , CH ₃ ( CH ₂ ) ₁₆ , CH ₃ (CH ₂ ) ₁₇ , CH ₃ (CH ₂ ) ₁₈ , CH ₃ (CH ₂ ) ₁₉ , CH ₃ (CH ₂ ) ₂₀ , etc., among these, CH ₃ (CH ₂ ) ₁₆ is particularly preferred.
R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a propyl group.
n represents an integer greater than or equal to 1, and 3-6 are preferable.
In addition, since the temperature inside the electrophotographic image forming apparatus becomes high due to the influence of the fixing device and the temperature around the photoreceptor may increase to nearly 50 ° C., the dialkylamine represented by the general formula (1) is used. The long-chain alkylamide compound having a melting point is preferably 55 ° C. or higher, more preferably 60 ° C. or higher. When the melting point is less than 55 ° C., for example, when used in a high-temperature and high-humidity environment, the ambient temperature of the photoreceptor increases, and the protective agent may adhere too much to the surface of the photoreceptor.

  Examples of the long-chain alkylamide compound having a dialkylamine represented by the general formula (1) include the following. In addition, it is not limited to these compounds.

As the protective agent containing at least the long-chain alkylamide compound having a dialkylamine represented by the general formula (1), another protective agent capable of removing the influence of a low resistance substance on the surface of the photoreceptor is used in combination. You can also. The other protective agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include long-chain fatty acid metal salts and long-chain alkyl group-containing urea compounds. Among these, high temperature and high humidity N-butyl-N′-stearyl urea and zinc stearate are particularly preferable from the viewpoint of the hydrophilicity preventing effect under the environment.
When the other protective agent is added, 400 parts by mass or less is preferable and 100 parts by mass or less is more preferable with respect to 100 parts by mass of the long-chain alkylamide compound having the dialkylamine represented by the general formula (1). preferable.

  The method for attaching a protective agent containing at least the long-chain alkylamide compound having the dialkylamine represented by the general formula (1) to the surface of the photoreceptor is not particularly limited and may be appropriately selected depending on the purpose. For example, (1) a method in which the surface of the photoconductor is adhered by bringing a cloth, brush, roller, blade, or the like having the long-chain alkylamide compound powder fine particles having the dialkylamine represented by the general formula (1) into contact therewith. (2) A long-chain alkylamide compound having a dialkylamine represented by the general formula (1) is placed in a molding machine, heated and melted, and the molded body processed into a rod shape is directly pressed onto the surface of the photoreceptor and applied. (3) Dialkyl once scraped with a brush or the like from a molded product of a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) The method of attaching rubbed long chain alkylamide compound powder to photoreceptors having amine, and the like. Among these, (2) and (3) are particularly preferable.

As a method for producing the molded product of the protective agent of (2) and (3), a known method may be used as a method of molding a solid substance for molding into a certain shape (for example, a prismatic shape or a cylindrical shape). Examples thereof include a melt molding method, a powder molding method, a hot press molding method, a cold isostatic pressing method (CIP), and a hot isostatic pressing method (HIP). Among these, the melt molding method is particularly preferable.
In the melt molding method, the protective agent is heated to its melting temperature or higher, a predetermined amount of the molten protective agent is poured into a mold having a predetermined shape, and if necessary, maintained at a temperature equal to or higher than the melting point for a certain time, and then allowed to cool. Or it can cool by removing and can obtain a molded object.
Next, after cooling to a temperature close to room temperature, the molded body is removed from the mold, and a molded body of a protective agent is obtained. Thereafter, the shape of the molded article of the protective agent may be adjusted by cutting or the like.
The metal mold (form frame) is preferably a metal metal mold such as steel, stainless steel, and aluminum because of its good thermal conductivity and good dimensional accuracy. Further, it is preferable to coat the inner wall surface of the mold with a release agent such as a fluororesin or a silicone resin in order to improve the releasability.

  In addition, there is no particular limitation on the method of forming an image using a photoconductor having a long-chain alkylamide compound having a dialkylamine on the surface, and it can be selected appropriately according to the purpose. For example, (i) image formation A method of forming an image using a photoconductor in which a long-chain alkylamide compound having a dialkylamine is previously attached to the surface before being mounted on the apparatus; (ii) a dialkylamine is applied to the surface of the photoconductor in the image forming apparatus by a protective agent attaching means. And (iii) a method using (i) and (ii) in combination, and the like. Among these, the methods (ii) and (iii) are particularly preferable.

-Protective agent adhesion means-
The protective agent attaching means includes, for example, a pressing force applying member that presses a molded body of the protective agent and contacts the protective agent supply member, and a protective agent supply member that supplies the image carrier protective agent to the surface of the image carrier. And a protective layer forming member for forming a protective layer by thinning the supplied protective agent, and further having other configurations as required.
The protective layer forming member may also serve as a cleaning unit. However, in order to more reliably form the protective layer, the cleaning unit removes the residual material mainly composed of the toner on the photosensitive member in advance. It is preferable not to mix in the protective layer.

Here, FIG. 2 is a schematic view showing an example of the protective agent attaching means of the present invention. This protective agent attaching means 7 also serves as a cleaning means for the image forming apparatus.
The protective layer forming means disposed to face the photoconductor 201 is mainly composed of a protective agent molded body 202, a protective agent supply member 203, a pressing force applying member 204, a protective layer forming member 205, and the like.

The molded body 202 of the protective agent is brought into contact with, for example, the brush-shaped protective agent supply member 203 by the pressing force from the pressing force applying member 204. The protective agent supply member 203 rotates and rubs with the photosensitive member 201 with a linear velocity difference. At this time, the protective agent held on the protective agent supply member surface is supplied to the photosensitive member surface.
Since the protective agent supplied to the surface of the photoconductor may not be a sufficient protective layer upon supply depending on the selection of the type of substance, in order to form a more uniform protective layer, for example, a protective layer having a blade-like member It is thinned by the forming member 205 to become a protective layer.
Although the protective layer forming member 205 is also used as a cleaning unit, a cleaning unit may be provided upstream of the protective agent attaching unit 7.

The material of the blade used for the protective layer forming member is not particularly limited and can be appropriately selected from known materials for cleaning blades according to the purpose. For example, urethane rubber, hydrin rubber, silicone rubber, fluorine For example, rubber. These may be used individually by 1 type and may use 2 or more types together. In these blades, the contact portion with the image carrier may be coated or impregnated with a low coefficient of friction material. Moreover, in order to adjust the hardness of an elastic body, you may disperse fillers, such as an organic filler and an inorganic filler.
The force for pressing the photosensitive member with the protective layer forming member is sufficient as the protective agent extends to the state of the protective layer, and the linear pressure is preferably 5 gf / cm to 80 gf / cm, and 10 gf / cm to 60 gf / cm. cm is more preferable.

<Photoconductor>
The photoconductor is not particularly limited as to the material, shape, structure, size, and the like, and can be appropriately selected according to the purpose. Examples of the shape include a drum shape, a sheet shape, and an endless belt. And the like. The structure may be a single-layer structure or a laminated structure, and the size may be appropriately selected according to the size and specifications of the image forming apparatus. Examples of the material include inorganic photoreceptors such as amorphous silicon, selenium, CdS, and ZnO; organic photoreceptors (OPC) such as polysilane and phthalopolymethine, and the like.

  For example, the amorphous silicon photosensitive member is heated at 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, a plasma CVD method, or the like is applied on the support. A photosensitive layer made of a-Si is formed by the film forming method. Among these, the plasma CVD method is particularly preferable, and specifically, a method in which the source gas is decomposed by direct current, high frequency, or microwave glow discharge to form a photosensitive layer made of a-Si on the support is preferable. .

The organic photoreceptor (OPC) has (1) optical characteristics such as a wide light absorption wavelength range and a large amount of light absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, (3) In general, it is widely applied because of the wide selection range of materials, (4) ease of production, (5) low cost, and (6) non-toxicity. The layer structure of such an organic photoreceptor is roughly divided into a single layer structure and a laminated structure.
The single-layered photoreceptor has a support and a single-layer type photosensitive layer provided on the support, and further includes a protective layer, an intermediate layer, and other layers as necessary.
The laminated structure of the photoreceptor comprises a support, and a laminate type photosensitive layer having at least a charge generation layer and a charge transport layer in this order on the support, and further includes a protective layer and an intermediate layer as necessary. And other layers.

<Charging step and charging means>
The charging step is a step of charging the surface of the photoreceptor, and is performed by a charging unit.
The charging means is not particularly limited as long as it can apply a voltage to the surface of the photoconductor to be uniformly charged, and can be appropriately selected according to the purpose. (1) Photoconductor Contact type charging means for charging in contact with the toner, and (2) non-contact type charging means for charging in a non-contact manner with the photoreceptor.

-Contact charging means-
Examples of the contact type charging means (1) include a conductive or semiconductive charging roller, a magnetic brush, a fur brush, a film, and a rubber blade. Among these, the charging roller can significantly reduce the amount of ozone generated compared to corona discharge, and is excellent in stability during repeated use of the photoreceptor, and is effective in preventing image quality deterioration.
The magnetic brush is composed of a nonmagnetic conductive sleeve that supports various ferrite particles such as Zn-Cu ferrite and a magnet roll included in the sleeve. The fur brush is formed by, for example, winding or pasting a fur treated with carbon, copper sulfide, metal, metal oxide, or the like around a metal or a treated metal core.

Here, FIG. 3 is a sectional view showing an example of the charging roller. The charging roller 310 includes a cored bar 311 serving as a columnar conductive support, a resistance adjusting layer 312 formed on the outer peripheral surface of the cored bar 311, and a surface of the resistance adjusting layer 312. And a protective layer 313 for preventing leakage.
The resistance adjusting layer 312 is formed by extruding or injection-molding a thermoplastic resin composition containing at least a thermoplastic resin and a polymer type ionic conductive agent on the peripheral surface of the core metal 311.
The resistivity value of the resistance adjustment layer 312 is preferably 10 ⁶ Ω · cm to 10 ⁹ Ω · cm. When the volume resistivity value exceeds 10 ⁹ Ω · cm, the charge amount is insufficient, and the photosensitive drum may not be able to obtain a sufficient charging potential to obtain a uniform image. If the value is less than 10 ⁶ Ω · cm, there is a risk of leakage to the entire photosensitive drum.

  There is no restriction | limiting in particular as a thermoplastic resin used for the said resistance adjustment layer 312, Although it can select suitably according to the objective, For example, polyethylene (PE), a polypropylene (PP), polymethyl methacrylate (PMMA), Examples thereof include polystyrene (PS) and copolymers thereof (AS, ABS, etc.).

As the polymer-type ion conductive agent, one having a resistance value of about 10 ⁶ to 10 ¹⁰ Ω · cm as a single substance and easily reducing the resistance of the resin is used. One example is a compound containing a polyetheresteramide component. In order to set the resistance value of the resistance adjusting layer 312 to the above value, the blending amount is preferably 30 parts by mass to 70 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
In addition, a quaternary ammonium base-containing polymer compound can be used as the polymer type ion conductive agent. Examples of the quaternary ammonium base-containing polymer compound include quaternary ammonium base-containing polyolefin. In order to set the resistance value of the resistance adjusting layer 312 to the above value, the blending amount is preferably 10 parts by mass to 40 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

  The polymer type ionic conductive agent can be dispersed in the thermoplastic resin by a biaxial kneader, a kneader or the like. Since the polymer type ionic conductive agent is uniformly dispersed at the molecular level in the thermoplastic resin composition, the resistance adjusting layer 312 is poorly dispersed in the conductive material found in the resistance adjusting layer in which the conductive pigment is dispersed. The accompanying resistance value does not vary. Moreover, since the polymer type ionic conductive agent is a polymer compound, it is uniformly dispersed and fixed in the thermoplastic resin composition, and bleedout hardly occurs.

The protective layer 313 is formed such that its resistance value is larger than that of the resistance adjustment layer 312. As a result, leakage to the defective portion of the photosensitive drum is avoided. However, if the resistance value of the protective layer 313 is excessively increased, the charging efficiency is decreased. Therefore, the difference between the resistance value of the protective layer 313 and the resistance value of the resistance adjustment layer 312 is preferably 10 ³ Ω · cm or less. .

  As the material for the protective layer 313, a resin material is preferable because of its good film formability. As the resin material, for example, a fluororesin, a polyamide resin, a polyester resin, a polyvinyl acetal resin and the like are preferable from the viewpoint of excellent non-adhesiveness and preventing toner adhesion. In addition, since the resin material generally has electrical insulation, if the protective layer 313 is formed of the resin material alone, the characteristics of the charging roller are not satisfied. Therefore, the resistance value of the protective layer 313 is adjusted by dispersing various conductive agents in the resin material. In order to improve the adhesion between the protective layer 303 and the resistance adjustment layer 302, a reactive curing agent such as isocyanate may be dispersed in the resin material.

  The charging roller 310 is connected to a power source and is applied with a predetermined voltage. The voltage may be only a direct current (DC) voltage, but is preferably a voltage obtained by superimposing an alternating current (AC) voltage on a DC voltage. By thus applying the AC voltage, the surface of the photosensitive drum can be more uniformly charged.

-Non-contact charging means-
The non-contact charging means (2) includes, for example, a non-contact charger using a corona discharge, a needle electrode device, a solid discharge element; conductive or semi-conductive disposed with a minute gap with respect to the photoreceptor. Charging roller. Among these, a charging roller disposed with a minute gap with respect to the photoreceptor is particularly preferable.

  The charging roller disposed with a minute gap with respect to the photosensitive member is an improvement of the charging roller so as to have a minute gap with respect to the photosensitive member. The fine gap is preferably 10 μm to 200 μm, and more preferably 10 μm to 100 μm.

Here, FIG. 4 is a schematic view showing an example of a non-contact charging roller. In FIG. 4, the charging roller 310 is disposed with a minute gap H with respect to the photosensitive drum 321. The minute gap H is set by causing the spacer member surface to contact the surface of the photosensitive drum 321 by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 310. be able to. In FIG. 4, 304 is a power source.
In FIG. 4, as a method for maintaining the minute gap H, a film 302 is wound around both ends of the charging roller 310 to form a spacer member. The spacer 302 is brought into contact with the photosensitive surface of the photosensitive member so that a certain minute gap H in the image area of the charging roller and the photosensitive member can be obtained. The applied bias applies an AC superposition type voltage to charge the photoconductor by a discharge generated in a minute gap H between the charging roller and the photoconductor. As shown in FIG. 4, the accuracy of maintaining the minute gap H is improved by pressing the shaft 311 of the charging roller with the spring 303.

The spacer member may be integrally formed with the charging roller. At this time, at least the surface of the gap portion is an insulator. As a result, the discharge at the gap portion is eliminated, and the discharge product is deposited on the gap portion, and the adhesion of the discharge product prevents the toner from adhering to the gap portion and spreading the gap.
Moreover, as the spacer member, a heat shrinkable tube may be used. Examples of such heat-shrinkable tubes include Sumitubes for 105 ° C. (trade name: F105 ° C., manufactured by Sumitomo Chemical Co., Ltd.).

<Exposure process and exposure means>
The exposure can be performed, for example, by exposing the surface of the photoconductor imagewise using the exposure unit.
The optical system in the exposure is roughly classified into an analog optical system and a digital optical system. The analog optical system is an optical system that projects a document directly onto a photoconductor by an optical system, and the digital optical system is supplied with image information as an electrical signal, which is converted into an optical signal to expose the photoconductor. This is an optical system that forms images.
The exposure means is not particularly limited as long as the surface of the photoreceptor charged by the charging means can be exposed like an image to be formed, and can be appropriately selected according to the purpose. Examples thereof include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system.
In the present invention, an optical backside system that performs imagewise exposure from the backside of the photoreceptor may be employed.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using toner or the developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using toner or the developer, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated, Suitable examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image, and a developing unit including the toner-containing container is more preferable.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the photoconductor, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is applied to the surface of the photoconductor by an electric attractive force. Moving. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the photoreceptor.
The developer accommodated in the developing device may be a one-component developer or a two-component developer.

-Transfer process and transfer means-
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the photoreceptor using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer unit (the primary transfer unit and the secondary transfer unit) preferably includes at least a transfer unit that peels and charges the visible image formed on the photoconductor toward the recording medium. There may be one transfer means or two or more transfer means.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the toner of each color is transferred to the recording medium, or for the toner of each color. You may perform this simultaneously in the state which laminated | stacked this.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
The heating in the heating and pressing means is preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

The neutralization step is a step of performing neutralization by applying a neutralization bias to the photoconductor, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited and may be any appropriate neutralization neutralizer as long as it can apply a neutralization bias to the photosensitive member. For example, a neutralization lamp is preferable. .

The cleaning step is a step of removing the toner remaining on the photoconductor, and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited and may be selected from known cleaners as long as it can remove the electrophotographic toner remaining on the photoreceptor, and includes, for example, a magnetic brush cleaner, a static cleaner, and the like. Preferred examples include an electric brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

An example of an electrophotographic image forming apparatus will be described with reference to FIG.
The image forming apparatus 1 includes a photoconductor 2, a charging unit 3 for charging the surface of the photoconductor, an exposure unit 4 for exposing the charged photoconductor surface to form an electrostatic latent image, and the electrostatic latent image. Developing means 5 that develops an image using toner to form a visible image, transfer means 6 that transfers the visible image to a recording medium, and fixing means 101 that fixes the transferred image transferred to the recording medium And at least other means as necessary. In FIG. 1, reference numeral 104 denotes a recording medium.

The surface of the photosensitive member 2 charged by the charging unit 3 is exposed to light modulated based on recorded information using an exposure unit 4 (light source) to form an electrostatic latent image on the photosensitive member 2.
Next, in the case of black, for example, when the developing means 5 is black, charged fine particles called toner formed of colored fine particles such as carbon black, a low melting point resin, and a charge control agent are brought into contact with the photosensitive member 2 to form an electrostatic latent image. To visualize. This toner image is transferred onto a recording medium by the transfer device 6. There are a method of transferring directly to a recording medium such as paper and film, and a method of transferring the toner once to an intermediate transfer member and then secondary transfer to a recording medium such as paper via the intermediate transfer member.
The toner transferred onto the recording medium is fixed on the recording medium by the fixing device 101.
The surface of the photosensitive member after the toner transfer is subjected to static charge removal on the surface by the charge removing means 102, and then the residual toner that has not been transferred is cleaned by the cleaning means 7 and used for the next information recording.
The cleaning means 7 is provided with a protective agent attaching means, and the protective agent 103 can be attached to the surface of the photoreceptor 2 by the protective agent attaching means. In this case, it is preferable to use a protective agent attaching means as shown in FIG.

Another mode for carrying out the image forming method of the present invention by the image forming apparatus will be described with reference to FIG. The tandem image forming apparatus shown in FIG. 5 is a tandem type color image forming apparatus. The tandem image forming apparatus includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.
The copying apparatus main body 150 is provided with an endless belt-like intermediate transfer member 50 at the center. The intermediate transfer member 50 is stretched around the support rollers 14, 15 and 16, and can be rotated clockwise in FIG. 5. An intermediate transfer member cleaning device 17 for removing residual toner on the intermediate transfer member 50 is disposed in the vicinity of the support roller 15. The intermediate transfer body 50 stretched by the support roller 14 and the support roller 15 is a tandem type in which four image forming means 18 of yellow, cyan, magenta, and black are arranged in parallel and facing each other along the conveyance direction. A developing device 120 is disposed. An exposure device 21 is disposed in the vicinity of the tandem developing device 120. A secondary transfer device 22 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the tandem developing device 120 is disposed. In the secondary transfer device 22, a secondary transfer belt 24, which is an endless belt, is stretched around a pair of rollers 23, and the transfer paper conveyed on the secondary transfer belt 24 and the intermediate transfer body 50 are in contact with each other. Is possible. A fixing device 25 is disposed in the vicinity of the secondary transfer device 22. The fixing device 25 includes a fixing belt 26 that is an endless belt, and a pressure roller 27 that is pressed against the fixing belt 26.
In the tandem image forming apparatus, a sheet reversing device 28 for reversing the transfer paper for image formation on both sides of the transfer paper is disposed in the vicinity of the secondary transfer device 22 and the fixing device 25. .

  Next, formation of a full-color image (color copy) using the tandem developing device 120 will be described. That is, first, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and the document is set on the contact glass 32 of the scanner 300. 400 is closed.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the contact glass 32. Immediately after that, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, light from the light source is irradiated by the first traveling body 33 and reflected light from the document surface is reflected by the mirror in the second traveling body 34 and is received by the reading sensor 36 through the imaging lens 35 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta, and cyan is stored in each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image) in the tandem developing device 120. Each of the image forming units forms black, yellow, magenta, and cyan toner images. That is, each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem type developing device 120 is photosensitive as shown in FIG. A photoconductor 10K (black photoconductor 10K, yellow photoconductor 10Y, magenta photoconductor 10M, and cyan photoconductor 10C), a charging device 160 for uniformly charging the photoconductor 10 and color image information. An exposure apparatus that exposes the photosensitive member to each color image based image (L in FIG. 6) and forms an electrostatic latent image corresponding to each color image on the photosensitive member; and the electrostatic latent image A developing device 61 that develops each color toner (black toner, yellow toner, magenta toner, and cyan toner) to form a toner image with each color toner; A transfer charger 62 for transferring the image onto the intermediate transfer member 50, a cleaning device 63, and a static eliminator 64 are provided, and each monochrome image (black image, yellow image) is based on the image information of each color. Image, magenta image, and cyan image). The black image, the yellow image, the magenta image, and the cyan image formed in this way are formed on the black photoconductor 10K on the intermediate transfer member 50 that is rotationally moved by the support rollers 14, 15, and 16, respectively. The black image, the yellow image formed on the yellow photoconductor 10Y, the magenta image formed on the magenta photoconductor 10M, and the cyan image formed on the cyan photoconductor 10C are sequentially transferred (primary transfer). Is done. Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member 50 to form a composite color image (color transfer image).

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed out a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. Each sheet is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 and stopped. Alternatively, the sheet feed roller 142 is rotated to feed out sheets (recording paper) on the manual feed tray 54, separated one by one by the separation roller 145, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. . The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the sheet. Then, the registration roller 49 is rotated in synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and a sheet (recording paper) is interposed between the intermediate transfer member 50 and the secondary transfer device 22. The secondary color transfer device 22 transfers the composite color image (color transfer image) onto the sheet (recording paper), thereby transferring the color image onto the sheet (recording paper). Is formed. The residual toner on the intermediate transfer member 50 after image transfer is cleaned by the intermediate transfer member cleaning device 17.

  The sheet (recording paper) on which the color image has been transferred is conveyed by the secondary transfer device 22 and sent to the fixing device 25, where the combined color image (color) is generated by heat and pressure. (Transfer image) is fixed on the sheet (recording paper). Thereafter, the sheet (recording paper) is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the discharge tray 57, or switched by the switching claw 55 and reversed by the sheet reversing device 28 and transferred again. After being guided to the position and recording an image on the back surface, the image is discharged by the discharge roller 56 and stacked on the discharge tray 57.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Example 1)
-Preparation of protective agent and molded body thereof-
Steric acid dimethylaminopropylamide [CH ₃ (CH ₂ ) ₁₆ CONH (CH ₂ ) ₃ N (CH ₃ ) ₂ ] powder (Daiichi Kogyo Seiyaku Co., Ltd., Catiogen SPA, melting point = 61.5 ° C.) in an electric furnace Then, the liquid melted by heating at 80 ° C. for 30 minutes was put in an aluminum forming jig, taken out in a room temperature atmosphere, and naturally cooled for 8 hours.
Next, the molded body was taken out from the molding jig and cut into a shape of 7 mm × 3 mm × 300 mm to prepare a molded body of dimethylaminopropylamide stearate.

(Production Example 2)
-Preparation of protective agent and molded body thereof-
Stearic acid dimethylaminopropylamide [CH ₃ (CH ₂ ) ₁₆ CONH (CH ₂ ) ₃ N (CH ₃ ) ₂ ] powder (Daiichi Kogyo Seiyaku Co., Ltd., Catiogen SPA, melting point = 61.5 ° C.) 50 parts by mass And 50 parts by mass of N-butyl-N′-stearyl urea (C ₁₈ H ₃₇ NHCONHC ₄ H ₉ ) powder (Nippon Kasei Co., Ltd., Haclean SB) in an electric furnace at 120 ° C. for 30 minutes The liquid melted by heating and mixing was put into an aluminum forming jig, taken out in a room temperature atmosphere, and naturally cooled for 8 hours.
Next, the molded body was taken out from the molding jig, cut into a shape of 7 mm × 3 mm × 300 mm, and a molded body of a mixture of two kinds of dimethylaminopropylamide stearate and N-butyl-N′-stearyl urea was produced.

(Production Example 3)
-Preparation of protective agent and molded body thereof-
Stearic acid dimethylaminopropylamide [CH ₃ (CH ₂ ) ₁₆ CONH (CH ₂ ) ₃ N (CH ₃ ) ₂ ] powder (Daiichi Kogyo Seiyaku Co., Ltd., Catiogen SPA, melting point = 61.5 ° C.) 50 parts by mass And 30 parts by mass of N-butyl-N′-stearyl urea (C ₁₈ H ₃₇ NHCONHC ₄ H ₉ ) powder (Nippon Kasei Co., Ltd., Haclean SB) and 20 parts by mass of zinc stearate powder The liquid heated and mixed at 120 ° C. for 30 minutes in an oven was placed in an aluminum forming jig, taken out in a room temperature atmosphere, and naturally cooled for 8 hours.
Next, the molded body is taken out from the molding jig, cut into a shape of 7 mm × 3 mm × 300 mm, and mixed with three types of stearic acid dimethylaminopropylamide, N-butyl-N′-stearyl urea, and zinc stearate powder. A molded body was produced.

(Production Example 4)
-Preparation of protective agent and molded body thereof-
Stearic acid dimethylaminopropylamide [CH ₃ (CH ₂ ) ₁₆ CONH (CH ₂ ) ₃ N (CH ₃ ) ₂ ] powder (Daiichi Kogyo Seiyaku Co., Ltd., Catiogen SPA, melting point = 61.5 ° C.) 50 parts by mass And 50 parts by mass of zinc stearate powder were heated and melted at 100 ° C. for 30 minutes in an electric furnace, and the mixed liquid was put into an aluminum forming jig, taken out in a room temperature atmosphere, and naturally left for 8 hours. Cooling was performed.
Next, the molded body was taken out from the molding jig and cut into a shape of 7 mm × 3 mm × 300 mm to prepare a molded body of a mixture of two kinds of dimethylaminopropylamide stearate and zinc stearate.

(Comparative Production Example 1)
-Preparation of protective agent and molded body thereof-
In Production Example 1, N-butyl-N′-stearyl urea (C ₁₈ H ₃₇ NHCONHC ₄ H ₉ ) powder (manufactured by Nippon Kasei Co., Ltd., Haclean SB) was used instead of the long-chain alkylamide compound having a dialkylamine. Except for the above, in the same manner as in Production Example 1, a molded article of N-butyl-N′-stearyl urea was produced.

(Comparative Production Example 2)
-Preparation of protective agent and molded body thereof-
A molded article of zinc stearate was produced in the same manner as in Production Example 1 except that zinc stearate powder was used in place of the long-chain alkylamide compound having a dialkylamine in Production Example 1.

(Examples 1-4 and Comparative Examples 1-3)
Next, the cleaning means with protective agent attaching means shown in FIG. 2 in which the molded body of each protective agent is set is attached in place of the cleaning means 7 with protective agent attaching means of the image forming apparatus shown in FIG. While applying a protective agent on the surface of the photoconductor in the apparatus, after printing 10,000 sheets continuously in an environment of 20 ° C. to 25 ° C. and 55% RH to 70% RH, an environment of 30 ° C. and 90% RH The image evaluation was performed by repeating the cycle of printing 10 sheets 10 times. As the photoreceptor, a multilayer photoreceptor having an undercoat layer, a charge generation layer, and a charge transport layer on an aluminum alloy cylindrical tube having a diameter of 40 mm, a length of 300 mm, and a thickness of 1 mm was used. As the toner, IPSiO SP toner manufactured by Ricoh Co., Ltd. was used.

<Image evaluation>
In the image evaluation, the output image was visually evaluated, and the determination was performed by ranking in the following five levels. The results are shown in Table 1. The abnormal image means background stain, image blur, and image flow caused by non-uniformity of various characteristics on the surface of the photoreceptor.
〔Evaluation criteria〕
5: Abnormal image is not observed at all and is good 4: Abnormal image is observed very slightly, no problem in rank 5-4 3: Abnormal image is observed very slightly, slightly in rank 4-3 There is a problem 2: Although an abnormal image is slightly observed, there is a slight problem in rank 3 1: An abnormal image is observed and becomes a problem

<Measurement of contact angle>
Next, using an electrostatic property measuring apparatus (manufactured by Kawaguchi Denki Seisakusho, EPA8100), each photoconductor was rotated at 1,000 rpm, and charging and exposure were repeated for a predetermined time to perform corona discharge treatment. Thereafter, as a substitute characteristic evaluation of the degree of hydrophilic substance formation on the surface of the photoreceptor, a contact angle (θ) with respect to pure water was measured. The results are shown in FIG.
The contact angle was measured using an automatic contact angle meter (manufactured by Kyowa Interface Chemical Co., Ltd.).
From the results of FIG. 7, it was found that Examples 1 to 4 had a larger contact angle (θ) with respect to pure water than Comparative Examples 2 to 3, and thus the surface of the photoreceptor was not made hydrophilic.

  The image forming apparatus and the image forming method of the present invention can prevent the occurrence of abnormal images such as scumming, image blurring, and image flow caused by nonuniformity of various characteristics of the surface of the photoreceptor, and can produce high-quality images for a long time. For example, laser printers, direct digital plate-making machines, full-color copiers using direct or indirect electrophotographic multicolor image development systems, full-color laser printers, and full-color plain paper fax machines are widely used. Can be used.

FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention. FIG. 2 is a schematic view showing an example of the protective agent attaching means in the image forming apparatus of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the charging roller in the image forming apparatus of the present invention. FIG. 4 is a schematic view showing an example of a non-contact charging roller in the image forming apparatus of the present invention. FIG. 5 is a schematic explanatory view showing an example in which the image forming method of the present invention is implemented by the image forming apparatus (tandem color image forming apparatus) of the present invention. 6 is a partially enlarged schematic explanatory view of the image forming apparatus shown in FIG. FIG. 7 is a graph showing the measurement results of the contact angle (θ) with respect to pure water in the examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoconductor 3 Charging means 4 Exposure means 5 Developing means 6 Transfer means 7 Cleaning means with protective agent attaching means 10 Photoconductor (photosensitive drum)
10K black photoconductor 10Y yellow photoconductor 10M magenta photoconductor 10C cyan photoconductor 14 support roller 15 support roller 16 support roller 17 intermediate transfer cleaning device 18 image forming means 20 charging roller 21 exposure device 22 secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure belt 28 Sheet reversing device 30 Exposure device 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Developer roller 44Y Developer roller 44M Developer Roller 44C Developing roller 45K Black developing unit 45Y Yellow developing unit 45M Magenta developing unit 45C Cyan developing unit 49 Registration roller 50 Intermediate transfer member 51 Roller 52 Separating roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 discharge tray 58 corona charger 60 cleaning device 61 developing device 62 transfer charger 63 photoconductor cleaning device 64 static eliminator 70 static elimination lamp 80 transfer roller 90 cleaning device 95 transfer paper 100 image forming apparatus 101 fixing means 102 static elimination means 103 protective agent DESCRIPTION OF SYMBOLS 104 Recording medium 120 Tandem type developing device 121 Heating roller 122 Fixing roller 123 Fixing belt 124 Pressure roller 125 Heating source 126 Cleaning roller 127 Temperature sensor 130 Document stage 14 Feed roller 143 paper bank 144 sheet cassette 145 separating roller 146 feed path 147 transport rollers 148 feed path 150 copying apparatus main body 160 a charging device 200 feeder table 300 Scanner 400 automatic document feeder (ADF)

Claims (6)

A photosensitive member, a charging unit for charging the surface of the photosensitive member, an exposing unit for exposing the charged surface of the photosensitive member to form an electrostatic latent image, and developing the electrostatic latent image with toner. An image forming apparatus having at least developing means for forming a visual image, transfer means for transferring the visible image to a recording medium, and fixing means for fixing the transferred image transferred to the recording medium,
An image forming apparatus, wherein a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the following general formula (1) is previously attached to the surface of the photoreceptor.

In the general formula (1), ^{R 1} represents an alkyl group having 8 to 20 carbon atoms. R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 or more.   The image forming apparatus according to claim 1, further comprising a protective agent attaching unit that attaches a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the general formula (1) to the surface of the photoreceptor.   The image forming apparatus according to claim 1, wherein the long-chain alkylamide compound having a dialkylamine represented by the general formula (1) has a melting point of 55 ° C. or higher.   The image forming apparatus according to claim 1, wherein the protective agent further contains at least one of N-butyl-N′-stearyl urea and zinc stearate.   The image forming apparatus according to claim 1, wherein the charging unit is a roller charging method in which charging is performed in contact with or close to the photosensitive member. A charging step for charging the surface of the photoreceptor, an exposure step for exposing the charged surface of the photoreceptor to form an electrostatic latent image, and developing the electrostatic latent image with toner to form a visible image. An image forming method comprising at least a development step, a transfer step for transferring the visible image to a recording medium, and a fixing step for fixing the transfer image transferred to the recording medium,
An image forming method comprising using, as the photoreceptor, a photoreceptor on which a protective agent containing at least a long-chain alkylamide compound having a dialkylamine represented by the following general formula (1) is attached in advance: .

In the general formula (1), ^{R 1} represents an alkyl group having 8 to 20 carbon atoms. R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms. n represents an integer of 1 or more.

Images