JP4728919B2 - Image forming method and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method in which a plurality of image forming elements suitable for a copying machine, a facsimile, a laser printer, a direct digital plate making machine, and the like are arranged.

  As a full-color image forming apparatus using an electrophotographic system, two systems are generally known. One is called a single method or a single drum method, and one electrostatic latent image carrier (hereinafter also referred to as “photosensitive member” or “electrophotographic photosensitive member”) is mounted in the apparatus. , Four developing members corresponding to four colors of cyan, magenta, yellow and black are mounted. In this single method, four color toner images are formed on the photoreceptor or the recording medium. In this method, the charging member, the exposure member, the transfer member, the cleaning member, and the fixing member arranged around the photosensitive member can be used in common, and are designed to be smaller and less expensive than the tandem method described later. Is possible.

  On the other hand, another system is called a tandem system or a tandem drum system (see Patent Document 1). In this method, at least a plurality of photoconductors are mounted in the apparatus. In general, a charging member, an exposure member, a developing member, a transfer member, and a cleaning member are arranged one by one on one photosensitive drum to form one image forming element, and the image forming element A plurality (generally four) are mounted. In this tandem system, a single color toner image is formed by one image forming element, and the toner image is sequentially transferred onto a recording medium to form a full color image. An advantage of this tandem method is that high-speed image formation is possible. This is because each color toner image can be created by parallel processing. Therefore, compared with the single method, the image forming processing time is about one-fourth, and four times higher speed printing can be handled. Further, there is an advantage that the durability of each member provided in the image forming element such as the photoreceptor can be substantially increased. This is because, in the single method, each process of charging, exposure, and development is performed four times with one photoconductor to form one full-color image, whereas in the tandem method, the above operation is performed with one photoconductor. This is because it is performed only once with the photoconductor.

However, the tandem method has a demerit that the entire apparatus becomes large and the cost becomes high because a plurality of image forming elements are arranged.
In order to solve the above-described problems, measures have been taken by reducing the diameter of the photoconductor, reducing the size of each member installed around the photoconductor, and reducing the size of one image forming element. As a result, the effect of reducing the material cost as well as the size of the device has been produced, and the cost of the entire device has been reduced somewhat. However, along with the downsizing and downsizing of such an apparatus, a new problem has arisen that the photosensitive member mounted on the image forming element has to be highly sensitive and greatly improved in stability.

  In order to take advantage of the high-speed printing that is the first purpose of the tandem method, it is necessary to perform the image forming process at high speed. Therefore, it is necessary to quickly attenuate the light when exposed from the sensitivity of the photoreceptor to be used, that is, from a charged state. In addition, the light attenuation characteristic needs to be maintained stably even during repeated use. In particular, in a tandem-type full-color electrophotographic apparatus in which a plurality of image forming elements are arranged, a specific color (for example, only black) is generally used depending on the ratio of colors output by the user to use. The body load is not uniform. In this case, there is a problem that the light attenuation characteristics of only some of the photoconductors are deteriorated, and the color tone is changed when a full color image in which colors are superimposed is output during repeated use.

  As described above, if the characteristics of the photoconductor are not stable, there is a problem in the output image quality, and an abnormal image such as a color change or a background stain occurs when the photoconductor is repeatedly used over a long period of time. is there.

JP-A-5-341617

  An object of the present invention is to solve the conventional problems in response to the above-mentioned demands and achieve the following object. That is, the present invention is an image in which a plurality of image forming elements that are highly durable, can form a full color image with stable quality even when used repeatedly, and can form a high speed full color image at low cost. An object is to provide a forming apparatus and an image forming method.

As a result of intensive studies by the present inventors in order to solve the above-described problems, an electrostatic latent image carrier and electrostatic latent image forming means are provided to obtain a high-quality, high-durability image forming apparatus compatible with high-speed full color. In order to further increase the speed and stability of the tandem type image forming apparatus having a plurality of image forming elements each having a developing unit and a transfer unit, The light attenuation characteristics of the image carrier need to be fast and stable. Specifically, the light of a plurality of electrostatic latent image carriers is not dependent on the usage of the photoconductor corresponding to each color. It was found that the damping characteristic should be uniformly small even after long-term repeated use.
In general, the electrostatic latent image bearing member causes a decrease in chargeability, a decrease in sensitivity, or an increase in the potential of the exposed portion due to repeated use. In many cases, these are basically caused by the charge transport material used in the photosensitive layer. It is possible to suppress side effects such as an increase in blood pressure. Therefore, it has been found that a so-called electrophotographic photosensitive member with a good trailing edge is required in which the potential after light attenuation after exposure is sufficiently reduced.
As a result of intensive investigations among many compounds based on the above findings, the present inventors have included a charge transport material having at least a specific structure in the photosensitive layer of the electrostatic latent image carrier. The present inventors have found that the above object can be achieved effectively and have made the present invention.

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> An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image with toner to make it visible An image forming apparatus in which a plurality of image forming elements having at least developing means for forming an image and transfer means for transferring the visible image to a recording medium are arranged,
The latent electrostatic image bearing member has a support and at least a photosensitive layer on the support, and the photosensitive layer contains at least a charge transport material represented by the following structural formula (1). An image forming apparatus characterized by the above.
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same as or different from each other. It may have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and a substituent. Represents any of the aralkyl groups that may be present. n is the number of repeating units and represents an integer of 0 to 100.
<2> The image forming element includes an electrostatic latent image carrier, and at least one unit selected from a charging unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. The image forming apparatus according to <1>, wherein the image forming apparatus is a detachable process cartridge.
<3> The image forming apparatus according to any one of <1> to <2>, wherein the photosensitive layer contains a charge transport material represented by the following structural formula (1-1).
However, in the structural formula (1-1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are represented by the structural formula (1). Represents the same meaning.
<4> The image forming apparatus according to any one of <1> to <3>, wherein the photosensitive layer contains a charge transport material represented by the following structural formula (1-2).
However, in the structural formula (1-2), R ¹ and R ² represent the same meaning as in the structural formula (1).
<5> The image forming apparatus according to any one of <1> to <4>, wherein the photosensitive layer further contains a charge transport material represented by the following structural formula (2).
However, in the structural formula (2), R ¹⁵ and R ¹⁶ may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ may be the same as or different from each other, and have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, or a substituent. Any one of an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and an optionally substituted aralkyl group.
<6> The image forming apparatus according to any one of <1> to <5>, wherein the photosensitive layer contains a charge generation material, and the charge generation material is phthalocyanine.
<7> The image forming apparatus according to <6>, wherein the charge generation material is titanyl phthalocyanine.
<8> Titanylphthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), and 9.4 Having a main peak at °, 9.6 °, and 24.0 °, and having a peak at 7.3 ° as the lowest-angled diffraction peak. The image forming apparatus according to <7>, wherein the image forming apparatus does not have a peak between 4 ° peak.
<9> The image forming apparatus according to any one of <7> to <8>, wherein the primary particles of titanyl phthalocyanine have a volume average particle size of 0.60 μm or less.
<10> The image forming apparatus according to any one of <1> to <9>, wherein the photosensitive layer has a single layer configuration.
<11> The image formation according to any one of <1> to <9>, wherein the photosensitive layer has a stacked structure including a charge generation layer containing at least a charge generation material and a charge transport layer containing at least a charge transport material. Device.
<12> An image forming apparatus includes: an intermediate transfer member on which a visible image formed on an electrostatic latent image carrier is primarily transferred; and a visible image carried on the intermediate transfer member on a recording medium as a secondary A plurality of color toner images are sequentially superimposed on the intermediate transfer member to form a color image, and the color image is secondarily transferred collectively onto the recording medium. The image forming apparatus according to any one of <1> to <11>.
<13> An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image with toner to make it visible An image forming method using an image forming apparatus in which a plurality of image forming elements having at least a developing unit for forming an image and a transfer unit for transferring the visible image to a recording medium are arranged,
The latent electrostatic image bearing member has a support and at least a photosensitive layer on the support, and the photosensitive layer contains at least a charge transport material represented by the following structural formula (1). This is an image forming method.
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same as or different from each other. It may have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and a substituent. Represents any of the aralkyl groups that may be present. n is the number of repetitions and represents an integer of 0 to 100.

The image forming apparatus of the present invention uses at least an electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image using toner. A plurality of image forming elements having a developing unit that forms a visible image by developing the image and a transfer unit that transfers the visible image to a recording medium,
The latent electrostatic image bearing member has a support and at least a photosensitive layer on the support, and the photosensitive layer contains at least a charge transport material represented by the structural formula (1). .
In the image forming apparatus of the present invention, by adopting the above configuration, it is possible to form a full-color image that is highly durable, stable in quality even with repeated use, and forms a high-speed full-color image at low cost. be able to.

  Since the image forming method of the present invention uses a tandem type image forming apparatus in which a plurality of image forming elements of the present invention are arranged, it is highly durable and can form a full color image with stable quality even after repeated use. And a high-speed full-color image can be formed at low cost.

  According to the present invention, conventional problems can be solved, high durability, high quality full color images can be formed even with repeated use, and high speed full color images can be formed at low cost. An image forming apparatus and an image forming method can be provided.

(Image forming apparatus and image forming method)
An image forming apparatus according to the present invention includes an electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image using toner. A plurality of image forming elements having at least a developing means for developing and forming a visible image and a transfer means for transferring the visible image to a recording medium, and further means appropriately selected as necessary For example, the image forming apparatus includes a fixing unit, a cleaning unit, a charge eliminating unit, a recycling unit, a control unit, and the like.
It is preferable that four image forming elements are arranged corresponding to four colors of cyan, magenta, yellow, and black.
The image forming method of the present invention uses the image forming apparatus of the present invention to form an electrostatic latent image on the electrostatic latent image carrier, and uses the toner for the electrostatic latent image. Development step for forming a visible image by developing, and a transfer step for transferring the visible image to a recording medium, and other steps appropriately selected as necessary, such as a fixing step and a cleaning step. , Including static elimination process, recycling process, control process, etc.

  The image forming method according to the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, and the other steps can be performed by the other units.

-Electrostatic latent image forming step and electrostatic latent image forming means-
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier.

<Electrostatic latent image carrier>
The latent electrostatic image bearing member includes a support and at least a photosensitive layer on the support, and further includes other layers as necessary.

In the first embodiment, the electrostatic latent image carrier has a photosensitive layer (hereinafter also referred to as “single-layer type photosensitive layer”) having a single layer structure on a support. Furthermore, it has other layers, such as an undercoat layer, as needed.
In the second embodiment, the latent electrostatic image bearing member includes a support, a photosensitive layer having a structure in which a charge generation layer and a charge transport layer are stacked on the support (hereinafter referred to as “stacked photosensitive layer”). And may further include other layers such as an undercoat layer as necessary. In the second embodiment, the charge generation layer and the charge transport layer may be laminated in reverse.
Sensitivity can be further improved by functionally separating the photosensitive layer in the latent electrostatic image bearing member into a charge generation layer containing at least a charge generation material and a charge transport layer containing at least a charge transport material. In addition, the range of selection of materials that can be used can be expanded.
On the other hand, the photosensitive layer in the latent electrostatic image bearing member is a single layer containing a charge generation material and a charge transport material in a single layer, so that the change in sensitivity due to wear is reduced and repeated. Changes in characteristics due to use can be minimized.

  Here, FIG. 1 is a schematic cross-sectional view of the electrostatic latent image carrier of the present invention, in which a photosensitive layer 202 is provided on a support 201. FIG. 2 shows a function-separated type in which the photosensitive layer includes a charge generation layer (CGL) 203 and a charge transport layer (CTL) 204, and is provided between the support 201 and the charge generation layer 203. In addition, an undercoat layer 205 is provided. The electrostatic latent image carrier of the present invention may have any combination of the above other layers and photosensitive layer types as long as it has at least the photosensitive layer 202 on the support 201. .

  The photosensitive layer contains at least a charge transporting material represented by the following structural formula (1), and contains a charge generating material and, if necessary, other components.

-Charge transport material-
As the charge transport material, a compound represented by the following structural formula (1) is used.
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same as or different from each other. It may have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and a substituent. Represents any of the aralkyl groups that may be present. n is the number of repeating units and represents an integer of 0 to 100.

  The alkyl group in the structural formula (1) preferably has 1 to 25 carbon atoms, more preferably 1 to 10 carbon atoms, specifically, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, n-pentyl group, n-hexyl group, n-peptyl group, n-octyl group, n-nonyl group, n-decyl group and the like in a straight chain; i-propyl group, s-butyl group, t-butyl Branched groups such as a group, methylpropyl group, dimethylpropyl group, ethylpropyl group, diethylpropyl group, methylbutyl group, dimethylbutyl group, methylpentyl group, dimethylpentyl group, methylhexyl group, dimethylhexyl group; alkoxyalkyl group Monoalkylaminoalkyl group, dialkylaminoalkyl group, halogen-substituted alkyl group, alkylcarbonylalkyl group, carboxyalkyl group, Group, alkanoyloxy group, an aminoalkyl group, esterified optionally alkyl group substituted with a carboxyl group which have, include an alkyl group substituted by a cyano group. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted alkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. Included in the alkyl group.

  The cycloalkyl group in the structural formula (1) preferably has 3 to 25 carbon atoms, more preferably 3 to 10 carbon atoms, specifically, a homologous ring from cyclopropane to cyclodecane; methylcyclopentane, dimethylcyclo Having an alkyl substituent such as pentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, tetramethylcyclohexane, ethylcyclohexane, diethylcyclohexane, t-butylcyclohexane; alkoxyalkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl group, halogen Substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, halogen atom, amino group, optionally esterified Carboxyl group, a cycloalkyl group substituted by a cyano group and the like. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted cycloalkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. It is included in the cycloalkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the aralkyl group in the structural formula (1) include a group in which an aromatic ring is substituted on the substituted or unsubstituted alkyl group, and an aralkyl group having 6 to 14 carbon atoms is preferable. More specifically, benzyl group, perfluorophenylethyl group, 1-phenylethyl group, 2-phenylethyl group, terphenylethyl group, dimethylphenylethyl group, diethylphenylethyl group, t-butylphenylethyl group, 3- Examples thereof include a phenylpropyl group, a 4-phenylbutyl group, a 5-phenylpentyl group, a 6-phenylhexyl group, a benzhydryl group, and a trityl group.

n is the number of repeating units and represents an integer of 0 to 100, preferably an integer of 0 to 5. n is determined from the weight average molecular weight (Mw). That is, the compound exists with a distribution in molecular weight. When n exceeds 100, the molecular weight of the compound increases and the solubility in various solvents decreases, so 100 or less is preferable. On the other hand, when n is 1, it is a trimer of naphthalene carboxylic acid, but excellent electron transfer characteristics can be obtained even for oligomers by appropriately selecting substituents for R ¹ and R ² . In this way, a wide range of naphthalenecarboxylic acid derivatives from oligomers to polymers are synthesized depending on the number of repeating units n.
In the range where the molecular weight of the oligomer region is small, monodispersed compounds can be obtained by stepwise synthesis. In the case of a compound having a large molecular weight, a compound having a distribution in molecular weight is obtained.
Among these, a charge transport material represented by the following structural formula (1-1) in which n is 0 is particularly preferable.
However, in the structural formula (1-1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are the structural formula (1). Means the same.

Furthermore, a charge transport material represented by the following structural formula (1-2) is preferable.
However, in said structural formula (1-2), R < ¹ > and R < ² > represent the same meaning as the said structural formula (1).

  Here, specifically, the charge transport materials represented by the following structural formulas (3) to (10) are preferable from the viewpoint that the obtained image has high quality. In these structural formulas, Me represents a methyl group.

However, in the structural formula (8), the terminal groups at both ends represent Me (methyl) groups.
However, in the structural formula (9), the terminal groups at both ends represent Me (methyl) groups.
However, in said structural formula (10), the terminal group of both ends represents a Me (methyl) group, and n represents the integer of 1-100.

Here, the charge transport material represented by the structural formula (1) can be synthesized mainly by the following two methods.
However, in said reaction formula, R < ¹ > -R < ¹⁴ > and n represent the same meaning as the said Structural formula (1).

However, in said reaction formula, R < ¹ > -R < ¹⁴ > and n represent the same meaning as the said Structural formula (1).

Moreover, as a manufacturing method of the charge transport material represented by the structural formula (1-1), for example, (i) a method of reacting a naphthalenecarboxylic acid or an anhydride thereof with amines to monoimidize, (ii) ) A method of adjusting the pH of naphthalene carboxylic acid or an anhydride thereof with a buffer solution and reacting with diamines.
The monoimidization of (i) is carried out without solvent or in the presence of a solvent. The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, benzene, toluene, xylene, chloronaphthalene, acetic acid, pyridine, methylpyridine, dimethylformamide, dimethylacetamide, dimethylethyleneurea, dimethyl It is preferable to use one that does not react with raw materials and products such as sulfoxide and reacts at a temperature of 50 to 250 ° C. For pH adjustment, it is preferable to use a buffer solution prepared by mixing a basic aqueous solution such as lithium hydroxide or potassium hydroxide with an acid such as phosphoric acid.
The carboxylic acid derivative dehydration reaction in which the carboxylic acid (i) and (ii) are reacted with amines or diamines is carried out in the absence of a solvent or in the presence of a solvent. There is no restriction | limiting in particular as said solvent, According to the objective, it can select suitably, For example, the temperature of 50-250 degreeC does not react with raw materials and products, such as benzene, toluene, chloronaphthalene, bromonaphthalene, and acetic anhydride. It is preferable to use what can be made to react. Any reaction may be performed without a catalyst or in the presence of a catalyst, and is not particularly limited. For example, molecular sieves, benzenesulfonic acid, p-toluenesulfonic acid and the like can be used as a dehydrating agent.

Here, the charge transport material represented by the structural formula (3) can be produced by the following method.
<First step>
In a 200 ml four-necked flask, 5.0 g (18.6 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 50 ml of N, N-dimethylformamide (DMF) are placed and heated to reflux. It was. To this, a mixture of 2.14 g (18.6 mmol) of 2-aminoheptane and 25 ml of N, N-dimethylformamide (DMF) was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Furthermore, the recovered product was recrystallized from toluene / hexane to obtain 2.14 g of monoimide A (yield 31.5% by mass).
<Second step>
In a 100 ml four-necked flask, 2.0 g (5.47 mmol) of monoimide A, 0.137 g (2.73 mmol) of hydrazine monohydrate, 10 mg of p-toluenesulfonic acid, and 50 ml of toluene were placed for 5 hours. Heated to reflux. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. Furthermore, the recovered product was recrystallized from toluene / ethyl acetate to synthesize 0.668 g (yield 33.7% by mass) of the charge transport material represented by the structural formula (3).

The charge transport material represented by the structural formula (4) can be produced by the following method.
<First step>
In a 200 ml four-necked flask, 10 g (37.3 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 0.931 g (18.6 mmol) of hydrazine monohydrate, p-toluenesulfone 20 mg of acid and 100 ml of toluene were added and heated to reflux for 5 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. The recovered product was recrystallized from toluene / ethyl acetate to obtain 2.84 g of dimer C (yield 28.7%).
<Second step>
In a 100 ml four-necked flask, 2.5 g (4.67 mmol) of dimer C and 30 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. To this, a mixture of 0.278 g (4.67 mmol) of 2-aminopropane and 10 ml of N, N-dimethylformamide (DMF) was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and the residue was purified by silica gel column chromatography to obtain 0.556 g of monoimide C (yield 38.5% by mass).
<Third step>
In a 50 ml four-necked flask, 0.50 g (1.62 mmol) of monoimide C and 10 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. A mixture of 0.186 g (1.62 mmol) of 2-aminoheptane and 5 ml of N, N-dimethylformamide (DMF) was added dropwise thereto with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized with toluene / hexane to synthesize 0.243 g (yield 22.4 mass%) of the charge transport material represented by the structural formula (4).

Further, the charge transport material represented by the structural formula (5) can be produced by the following method.
<First step>
In a 200 ml four-necked flask, 5.0 g (18.6 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 50 ml of N, N-dimethylformamide (DMF) are placed and heated to reflux. It was. A mixture of 1.10 g (18.6 mmol) of 2-aminopropane and 25 ml of N, N-dimethylformamide (DMF) was added dropwise thereto with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to obtain 2.08 g of monoimide B (yield 36.1% by mass).
<Second step>
In a 100 ml four-necked flask, 2.0 g (6.47 mmol) of monoimide B, 0.162 g (3.23 mmol) of hydrazine monohydrate, 10 mg of p-toluenesulfonic acid, and 50 ml of toluene were placed for 5 hours. Heated to reflux. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. Furthermore, the recovered product was recrystallized with toluene / ethyl acetate to synthesize 0.810 g (yield 37.4% by mass) of the charge transport material represented by the structural formula (5).

Moreover, the charge transport material represented by the structural formula (6) can be produced by the following method.
<First step>
In a 200 ml four-necked flask, 5.0 g (9.39 mmol) of the dimer C described above and 50 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. To this, a mixture of 1.08 g (9.39 mmol) of 2-aminoheptane and 25 ml of N, N-dimethylformamide (DMF) was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and purified by silica gel column chromatography to obtain 1.66 g of monoimide D (yield 28.1% by mass).
<Second step>
In a 100 ml four-necked flask, 1.5 g (2.38 mmol) of monoimide D and 50 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. To this, a mixture of 0.308 g (2.38 mmol) of 2-aminooctane and 10 ml of N, N-dimethylformamide (DMF) was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to synthesize 0.328 g (yield 18.6% by mass) of the charge transport material represented by the structural formula (6).

The charge transport material represented by the structural formula (7) can be produced by the following method.
<First step>
In a 200 ml four-necked flask, 5.0 g (9.39 mmol) of the dimer C described above and 50 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. To this, a mixture of 1.08 g (9.39 mmol) of 2-aminoheptane and 25 ml of N, N-dimethylformamide (DMF) was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and purified by silica gel column chromatography to obtain 1.66 g of monoimide D (yield 28.1% by mass).
<Second step>
In a 100 ml four-necked flask, 1.5 g (2.38 mmol) of monoimide D and 50 ml of N, N-dimethylformamide (DMF) were placed and heated to reflux. A mixture of 0.408 g (2.38 mmol) of 6-aminoundecane and 10 ml of N, N-dimethylformamide (DMF) was added dropwise thereto with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to synthesize 0.276 g (yield 14.8% by mass) of the charge transport material represented by the structural formula (7).

The charge transport material represented by the structural formula (8) can be produced by the following method.
<First step>
A 200 ml four-necked flask was charged with 5.0 g (18.6 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 50 ml of N, N-dimethylformamide (DMF) and heated to reflux. To this, a mixture of 1.62 g (18.6 mmol) of 2-aminopentane and 25 ml of DMF was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Furthermore, the recovered product was recrystallized with toluene / hexane to obtain 3.49 g of monoimide E (yield 45.8%).
<Second step>
In a 100 ml four-necked flask, 3.0 g (7.33 mmol) of monoimide E, 0.983 g (3.66 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride, hydrazine monohydrate 0.368 g (7.33 mmol), p-toluenesulfonic acid 10 mg, and toluene 50 ml were added and heated to reflux for 5 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified twice by silica gel column chromatography. Furthermore, the recovered product was recrystallized from toluene / ethyl acetate to obtain 0.939 g (yield 13.7%) of the compound represented by the structural formula (8).
In mass spectrometry (FD-MS), the peak of M / z = 934 was observed and identified as the target product. In the elemental analysis, the calculated values are 66.81% carbon, 3.67% hydrogen, and 8.99% nitrogen, whereas the measured values are 66.92% carbon, 3.74% hydrogen, and 9.05% nitrogen. Met.

In addition to the charge transport materials represented by the structural formulas (1), (1-1), and (1-2), a charge transport material represented by the following structural formula (2) is further added. In addition, when the support is made of a flexible sheet such as an aluminum-deposited PET sheet or a nickel belt, the warpage generally referred to as curl may be reduced. It becomes possible. Moreover, since the film becomes dense by the addition, there is an advantage that the film is hardly affected by the acidic gas, that is, the gas resistance is improved.
However, in the structural formula (2), R ¹⁵ and R ¹⁶ may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ may be the same as or different from each other, and have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, or a substituent. Any one of an alkyl group which may be substituted, a cycloalkyl group which may have a substituent, and an aralkyl group which may have a substituent.

Specific examples of the charge transport material represented by the structural formula (2) include the following compounds.
However, in the structural formula (11), the terminal groups at both ends represent Me (methyl group).
However, in the structural formula (12), the terminal groups at both ends represent Me (methyl group).

  The addition amount of the charge transport material represented by the structural formula (2) is not particularly limited and may be appropriately selected depending on the purpose, but is 1 to 50% by mass with respect to the total amount of the charge transport material. Is preferable, and 5-30 mass% is more preferable. When the addition amount is less than 1% by mass, the film quality improvement is slight and no clear effect is observed, and when it exceeds 50% by mass, the charge transport ability tends to be slightly lowered.

-Charge generation material-
The charge generation material is not particularly limited and may be appropriately selected from known charge generation materials according to the purpose. However, the compound having a phthalocyanine structure is a combination of the charge transport material of the present invention. It is preferable from the point.
Among these, titanyl phthalocyanine represented by the following structural formula (i) having titanium as a central metal can be a highly sensitive photosensitive layer, and can further reduce the size and speed of the image forming apparatus. This is particularly preferable in that it becomes possible.

However, in the structural formula (i), X ₁ , X ₂ , X ₃ , and X ₄ may be the same as or different from each other, and represent various halogen atoms. n, m, l, and k may be the same as or different from each other, and represent an integer of 0 to 4.

References relating to the synthesis method and electrophotographic characteristics of the titanyl phthalocyanine include, for example, JP-A-57-148745, JP-A-59-36254, JP-A-59-44054, JP-A-59-31965. And JP-A-61-239248 and JP-A-62-67094.
In addition, various crystal systems are known for titanyl phthalocyanine. JP-A-59-49544, JP-A-59-41616959166959, JP-A-61-239248, JP-A-62-67094. Crystal, Japanese Patent Laid-Open No. 63-366, Japanese Patent Laid-Open No. 63-116158, Japanese Patent Laid-Open No. 63-196067, Japanese Patent Laid-Open No. 64-17066, Japanese Patent Laid-Open No. 2001-19871, etc. Different forms of titanyl phthalocyanine are described.
Of these crystal forms, titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° with a Bragg angle 2θ exhibits particularly excellent sensitivity characteristics and is used favorably. In particular, it has a maximum diffraction peak at 27.2 ° described in JP-A-2001-19871, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, Further, by using titanyl phthalocyanine having a peak at 7.3 ° as the diffraction peak on the lowest angle side and having no peak between the 7.4 ° peak and the 9.4 ° peak, Without losing sensitivity, it is possible to obtain a stable electrophotographic photosensitive member that does not cause a decrease in chargeability even when used repeatedly.
Furthermore, by using a titanyl phthalocyanine crystal whose primary particles have a volume average particle size of 0.60 μm or less, a stable electrophotographic photosensitive member that does not deteriorate chargeability even after repeated use without losing high sensitivity is obtained. And the soil dirt characteristics can be remarkably improved. This is because when the volume average particle diameter of the primary particles exceeds 0.60 μm, the contact area decreases and the charge generation efficiency decreases.

<Multi-layer type photosensitive layer>
As described above, the multilayer photosensitive layer includes at least a charge generation layer and a charge transport layer in this order, and further includes other layers as necessary.

-Charge generation layer-
The charge generation layer includes at least a charge generation material, and includes a binder resin and, if necessary, other components.
The charge generating substance is not particularly limited and may be appropriately selected depending on the intended purpose. As described above, phthalocyanine is preferable, and titanyl phthalocyanine is particularly preferable. The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, and is 9.4 °. , 9.6 °, and 24.0 °, and the lowest diffraction peak at 7.3 °, the 7.3 ° peak and the 9.4 ° peak. Those having no peak between the peaks of ° are preferred.
The content of the charge generation material in the charge generation layer is preferably 10 to 100% by mass, and more preferably 20 to 80% by mass.

  There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a polyamide resin, a polyurethane resin, an epoxy resin, a polyketone resin, a polycarbonate resin, a silicone resin, an acrylic resin, a polyvinyl butyral resin, polyvinyl Formal resin, polyvinyl ketone resin, polystyrene resin, poly-N-vinyl carbazole resin, polyacrylamide resin, and the like can be given. These may be used individually by 1 type and may use 2 or more types together.

  In addition, you may add charge transport substances other than the above as needed. In addition to the binder resin described above, a polymer charge transport material can be added as the binder resin for the charge generation layer.

Methods for forming the charge generation layer include a vacuum thin film fabrication method and a casting method from a solution dispersion system.
Examples of the former method include a glow discharge polymerization method, a vacuum deposition method, a CVD method, a sputtering method, a reactive sputtering method, an ion plating method, and an accelerated ion injection method. This vacuum thin film manufacturing method can satisfactorily form the inorganic material or organic material described above.
In order to provide the charge generation layer by the latter casting method, it is possible to use a charge generation layer coating solution and a conventional method such as a dip coating method, a spray coating method, or a bead coating method.

Examples of the organic solvent used in the charge generation layer coating solution include acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, dichloroethane, dichloropropane, trichloroethane, trichloroethylene, tetrachloroethane, and tetrahydrofuran. , Dioxolane, dioxane, methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, ethyl cellosolve, propyl cellosolve and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, tetrahydrofuran, methyl ethyl ketone, dichloromethane, methanol, and ethanol having a boiling point of 40 to 80 ° C. are particularly preferable because they can be easily dried after coating.
The charge generation layer coating solution is prepared by dispersing or dissolving the charge generation material and a binder resin in the organic solvent. Examples of the method for dispersing the organic pigment in the organic solvent include a dispersion method using a dispersion medium such as a ball mill, a bead mill, a sand mill, and a vibration mill, and a high-speed liquid collision dispersion method.
The thickness of the charge generation layer is not particularly limited and may be appropriately selected depending on the intended purpose.

-Charge transport layer-
The charge transport layer is a layer intended to hold a charged charge and to couple the charge generated and separated in the charge generating layer by exposure to the charged charge that has been held. In order to achieve the purpose of holding the charged charge, it is required that the electric resistance is high. Further, in order to achieve the purpose of obtaining a high surface potential with the charged charge that has been held, it is required that the dielectric constant is small and the charge mobility is good.

  The charge transport layer includes at least a charge transport material, and includes a binder resin and, if necessary, other components.

As the charge transport material, as described above, the charge transport material represented by the structural formula (1) is used.
Further, if necessary, a known charge transport material, that is, an electron transport material (acceptor) and a hole transport material (donor) can be used in combination.
Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2 , 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7 -Trinitrodibenzothiophene-5,5-dioxide, and the like. These may be used individually by 1 type and may use 2 or more types together.
Examples of the hole transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl). Examples include propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the charge transport material added is preferably 40 to 200 parts by mass, more preferably 70 to 150 parts by mass with respect to 100 parts by mass of the binder resin.

Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, phenol resin, epoxy resin, polyurethane resin, polyvinylidene chloride resin, Alkyd resins, silicone resins, polyvinyl carbazole resins, polyvinyl butyral resins, polyvinyl formal resins, polyacrylate resins, polyacrylamide resins, phenoxy resins, and the like are used. These may be used individually by 1 type and may use 2 or more types together.
For the purpose of ensuring the stability of the charge transport layer against environmental fluctuations, when an electrically inactive polymer compound is used, for example, polyester, polycarbonate, acrylic resin, polystyrene, polyvinyl chloride, polyvinyl chloride, Vinylidene, polyethylene, polypropylene, fluororesin, polyacrylonitrile, acrylonitrile / styrene / butadiene copolymer, styrene / acrylonitrile copolymer, ethylene / vinyl acetate copolymer and the like are preferable. Here, the electrically inactive polymer compound means a polymer compound that does not contain a chemical structure exhibiting photoconductivity such as a triarylamine structure.
When these resins are used in combination with a binder resin as an additive, the addition amount is preferably 50% by mass or less because of restrictions on light attenuation sensitivity.

The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent, and applying and drying the solution. In addition to the charge transport material and the binder resin, an appropriate amount of additives such as a plasticizer, an antioxidant, and a leveling agent may be added to the charge transport layer as necessary. These may be used individually by 1 type and may use 2 or more types together.
The thickness of the charge transport layer is preferably 15 to 40 μm, more preferably 15 to 30 μm, and still more preferably 15 to 25 μm.

<Single layer type photosensitive layer>
The single-layer type photosensitive layer includes a charge generation material, a charge transport material, and a binder resin, and further includes other components as necessary.
As the charge generation material, the charge transport material, and the binder resin, the same materials as those of the multilayer photosensitive layer can be used.
The amount of the charge generating material added is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin. Further, the amount of the charge transport material added is preferably 40 to 200 parts by mass, more preferably 70 to 150 parts by mass with respect to 100 parts by mass of the resin component.

  When a monolayer type photosensitive layer is provided by a casting method, it can be formed by dissolving or dispersing a charge generating material, a low molecular weight material and a high molecular charge transporting material in an appropriate solvent, and applying and drying the material. The single-layer type photosensitive layer may further contain a plasticizer and a binder resin as necessary. As the binder resin, the same binder resin as that of the charge transport layer can be used.

  The thickness of the single-layer type photosensitive layer is preferably 10 to 45 μm, more preferably 15 to 32 μm, still more preferably 15 to 25 μm. When the thickness is less than 10 μm, the chargeability may be lowered, and when it exceeds 45 μm, the sensitivity may be lowered.

<Support>
There is no restriction | limiting in particular as said support body, Although it can select suitably according to the objective, The thing which shows the electroconductivity whose volume resistance is 10 < ¹⁰ > ohm * cm or less is suitable.
The material, shape, size, etc. of the support are not particularly limited, and any of a plate shape, a drum shape, or a belt shape can be used. For example, aluminum, nickel, chromium, nichrome, copper, gold, and the like can be used. Metals such as silver and platinum, metal oxides such as tin oxide and indium oxide by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc. Further, after making them into a raw pipe by a method such as extruding and drawing them, a pipe subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in JP-A-52-36016 can also be used as a support.

In addition to the above, it is also possible to use a conductive layer formed by dispersing conductive powder on an appropriate binder resin and coating the support.
Examples of the material of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide such as conductive tin oxide and ITO. Examples include powder.
Examples of the binder resin include polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer. Polymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, poly-N-vinyl carbazole resin, acrylic resin , Silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin and the like.
The conductive layer can be formed by applying a coating solution obtained by dissolving or dispersing the conductive powder and a binder resin in a solvent on a support. Examples of the solvent include tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and the like.

  The conductive powder is contained in the cylindrical substrate in polyvinyl chloride resin, polypropylene resin, polyester resin, polystyrene resin, polyvinylidene chloride resin, polyethylene resin, chlorinated rubber, polytetrafluoroethylene fluorine resin, or the like. It is also preferable to provide a conductive layer with a heat shrinkable tube.

-Undercoat layer-
An undercoat layer may be further provided between the support and the photosensitive layer as necessary. The undercoat layer generally contains a resin as a main component. These resins are preferably resins having high solvent resistance with respect to general organic solvents in consideration of applying the photosensitive layer thereon with a solvent.
Examples of the resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane resins, melamine resins, phenol resins, alkyd-melamine resins, Examples thereof include curable resins that form a three-dimensional network structure, such as epoxy resins.

In addition, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, etc. is added to the undercoat layer in order to prevent moire and reduce residual potential. Also good.
The undercoat layer can be formed using the same solvent and coating method as the photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. For the undercoat layer, an anodized layer of Al ₂ O ₃ , an organic material such as polyparaxylylene (parylene), or an inorganic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, or CeO ₂ is vacuumed. Those provided by the thin film manufacturing method can also be used favorably. In addition, known ones can be used.
There is no restriction | limiting in particular in the thickness of the said undercoat layer, According to the objective, it can select suitably, 0.1-10 micrometers is preferable and 1-5 micrometers is more preferable.

In the electrostatic latent image carrier of the present invention, the photosensitive layer, the charge generation layer, the charge transport layer, the subbing layer are used for the purpose of preventing the decrease in sensitivity and the increase in residual potential, in order to improve the environmental resistance. An antioxidant can be added to each layer such as a layer.
Examples of the antioxidant include phenolic compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, and organic phosphorus compounds.
Examples of the phenol compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl- 6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3 -Tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy Ben ) Benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3 ′) -T-butylphenyl) butyric acid] cricol ester, tocopherols and the like.
Examples of the paraphenylenediamines include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- Examples include p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine, and the like.
Examples of the hydroquinones include 2,5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl. Examples include hydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone.
Examples of the organic sulfur compounds include dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like. .
Examples of the organic phosphorus compounds include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant is preferably 0.01 to 10% by mass with respect to the total mass of the layer to be added.

The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the image carrier and then performing imagewise exposure, and can be performed by the electrostatic latent image forming unit. .
The electrostatic latent image forming unit includes, for example, at least a charger that uniformly charges the surface of the image carrier and an exposure unit that exposes the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers using corona discharge such as corotrons and corotrons.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In the present invention, an optical back side system in which imagewise exposure is performed from the back side of the image carrier may be adopted.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.

<Toner>
The production method and material of the toner are not particularly limited, and can be appropriately selected from known ones according to the purpose. No. 1 (2004), etc., a pulverization classification method, a suspension polymerization method, an emulsion polymerization method, wherein an oil phase is emulsified, suspended or aggregated in an aqueous medium to form toner base particles. Examples thereof include a polymer suspension method.

  The pulverization method is, for example, a method of obtaining the toner base particles by melting and kneading the toner material, pulverizing, classifying, and the like. In the pulverization method, for the purpose of making the toner spherical, the shape may be controlled by applying a mechanical impact force to the obtained toner base particles. In this case, the mechanical impact force can be applied to the toner base particles using a device such as a hybridizer or mechanofusion.

The suspension polymerization method is an oil-soluble polymerization initiator, emulsification described later in an aqueous medium in which a colorant, a release agent, and the like are dispersed in a polymerizable monomer and a surfactant and other solid dispersant are contained. Emulsified and dispersed by the method. Thereafter, a polymerization reaction is performed to form particles, and then wet processing for attaching inorganic fine particles to the toner particle surfaces in the present invention may be performed. At that time, it is preferable to treat the toner particles from which excess surfactant and the like are removed by washing.
Examples of the polymerizable monomer include acrylic acids, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and other acids, acrylamide, By using a part of acrylate or methacrylate having amino group such as methacrylamide, diacetone acrylamide or their methylol compounds, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, dimethylaminoethyl methacrylate, etc. Functional groups can be introduced.
Further, by selecting a dispersant having an acid group or a basic group as a dispersant to be used, the dispersant can be adsorbed and left on the particle surface to introduce a functional group.

  As the emulsion polymerization method, a water-soluble polymerization initiator and a polymerizable monomer are emulsified in water using a surfactant, and a latex is synthesized by a usual emulsion polymerization method. Separately, a dispersion in which a colorant, a release agent and the like are dispersed in an aqueous medium is prepared, and after mixing, the toner is aggregated to a toner size and heat-fused to obtain a toner. Thereafter, wet processing of inorganic fine particles described later may be performed. A functional group can be introduced on the surface of the toner particles by using a latex similar to the monomer that can be used in the suspension polymerization method.

  Among these, since the selectivity of the resin is high, the low-temperature fixability is high, the granulation property is excellent, and the particle size, the particle size distribution, and the shape can be easily controlled. It is preferable that the toner is granulated by emulsifying or dispersing the dispersion in an aqueous medium.

The toner material solution is obtained by dissolving the toner material in a solvent, and the toner material dispersion liquid is obtained by dispersing the toner material in a solvent.
Examples of the toner material include an adhesive base obtained by reacting an active hydrogen group-containing compound, a polymer capable of reacting with the active hydrogen group-containing compound, a binder resin, a release agent, and a colorant. And, if necessary, other components such as resin fine particles and a charge control agent.
The adhesive substrate exhibits adhesiveness to a recording medium such as paper, and is formed by reacting the active hydrogen group-containing compound and a polymer capable of reacting with the active hydrogen group-containing compound in the aqueous medium. It may contain at least a polymer and may further contain a binder resin appropriately selected from known binder resins.

The volume average particle size of the toner is preferably 3 to 8 μm, and more preferably 3 to 6 μm. If the volume average particle size is less than 3 μm, the proportion of fine powder toner having a particle size of 1 μm or less that tends to cause image defects may increase. It may be difficult to deal with
The volume average particle diameter can be measured using, for example, a particle size measuring device “Coulter Counter TAII” manufactured by Coulter Electronics.

Further, the average circularity of the toner is preferably 0.90 or more, and more preferably 0.95 or more. When the average circularity is 0.90 or more, developability and transferability are improved, and a high-quality image can be obtained.
Here, the average circularity of the toner is, for example, an optical detection band in which a suspension containing toner is passed through an imaging unit detection zone on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. For example, it can be measured using a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation).

<Developer>
The developer contains at least the toner and contains other appropriately selected components such as a carrier. The developer may be a one-component developer or a two-component developer. However, when it is used for a high-speed printer or the like corresponding to the recent improvement in information processing speed, the life is improved. In view of the above, the two-component developer is preferable.
In the case of the one-component developer using the toner, even if the balance of the toner is performed, the fluctuation of the toner particle diameter is small, the filming of the toner on the developing roller, and a blade for thinning the toner The toner is not fused to such a member, and good and stable developability and an image can be obtained even when the developing device is used for a long time (stirring). Further, in the case of the two-component developer using the toner, even if the toner balance for a long period of time is performed, the fluctuation of the toner particle diameter in the developer is small, and it is good and stable even for a long period of stirring in the developing device. Developability is obtained.

  There is no restriction | limiting in particular as said carrier, Although it can select suitably according to the objective, What has a core material and the resin layer which coat | covers this core material is preferable.

  The core material is not particularly limited and may be appropriately selected from known materials. For example, 50 to 90 emu / g manganese-strontium (Mn-Sr) -based material, manganese-magnesium (Mn -Mg) -based materials and the like are preferable, and high magnetization materials such as iron powder (100 emu / g or more) and magnetite (75 to 120 emu / g) are preferable in terms of securing image density. In addition, weak magnetization such as copper-zinc (Cu—Zn) (30 to 80 emu / g) is advantageous in that the contact with the image bearing member in which the toner is in a standing state can be weakened, which is advantageous for high image quality. Material is preferred. These may be used alone or in combination of two or more.

The particle diameter of the core material is preferably an average particle diameter (volume average particle diameter (D ₅₀ )) of 10 to 200 μm, and more preferably 40 to 100 μm.

  The material of the resin layer is not particularly limited and can be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, Polyester resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, fluorine And a copolymer of vinylidene fluoride and vinyl fluoride, a fluoroterpolymer such as a terpolymer of tetrafluoroethylene, vinylidene fluoride and a non-fluorinated monomer, and a silicone resin. These may be used individually by 1 type and may use 2 or more types together.

  The resin layer may contain conductive powder or the like as necessary. Examples of the conductive powder include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control electric resistance.

For example, the resin layer is prepared by dissolving the silicone resin or the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material by a known coating method, drying, and baking. It can be formed by doing. Examples of the coating method include a dipping method, a spray method, and a brush coating method.
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cellosolve, and butyl acetate.
The baking is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, etc. The method of using, the method of using a microwave, etc. are mentioned.

  The amount of the resin layer in the carrier is preferably 0.01 to 5.0% by mass. When the amount is less than 0.01% by mass, it may not be possible to form the uniform resin layer on the surface of the core material. When the amount exceeds 5.0% by mass, the resin layer becomes too thick. As a result, granulation of carriers occurs, and uniform carrier particles may not be obtained.

When the developer is the two-component developer, the content of the carrier in the two-component developer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 90 to 98% by mass Is preferable, and 93-97 mass% is more preferable.
The mixing ratio of the toner and the carrier of the two-component developer is preferably 1 to 10.0 parts by mass of the toner with respect to 100 parts by mass of the carrier.

The visible image can be formed, for example, by developing the electrostatic latent image using a toner or a 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 developer, and can be appropriately selected from known ones. Preferable examples include at least a developing unit capable of applying the toner or the developer to the electrostatic latent image in contact or non-contact.

  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 or a developer having a stirrer for charging the toner or developer by frictional stirring and a rotatable magnet roller is preferable.

  In the developing unit, for example, the toner and the carrier are mixed and stirred, 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 image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the image carrier. Move to the surface. 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 image carrier.

  The developer accommodated in the developing device is a developer containing toner, but the developer 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 to a recording medium, but using an intermediate transfer member,
A mode in which a visible image is primarily transferred onto the intermediate transfer member and then the secondary image is secondarily transferred onto the recording medium is preferable. The toner is a toner having two or more colors, preferably a full color toner. More preferable is a mode including a primary transfer step in which a composite transfer image is formed by transferring the toner onto an intermediate transfer member, and a secondary transfer step in which the composite transfer image is transferred onto a recording medium.
The transfer can be performed, for example, by charging the image carrier with the visible image 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 image carrier to the recording medium side. . 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 typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

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. These may be performed simultaneously in a stacked state.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective from well-known things, For example, a 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 image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. For example, a neutralization lamp or the like is preferable. It is done.

Although the cleaning step will be described in detail later, it is a step of removing the electrophotographic toner remaining on the image carrier and can be suitably performed by a cleaning means.
The cleaning unit is not particularly limited, and can remove the toner remaining on the image carrier. In the image forming apparatus of the present invention, at least a cleaning blade is used.

The recycling step is a step of recycling the electrophotographic 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 means is a process for controlling the respective steps, and can be suitably performed by the control means.
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.

Here, the image forming apparatus used in the present invention will be described with reference to the drawings. In any of the drawings, the electrostatic latent image carrier is an electrostatic latent image carrier that satisfies the requirements of the present invention.
FIG. 3 is a schematic diagram for explaining an example of the image forming apparatus according to the present invention, and modifications as described below also belong to the category of the present invention.
In FIG. 3, an electrostatic latent image carrier (photoconductor) 311 is an electrostatic latent image carrier that satisfies the requirements of the present invention.
The photosensitive member 311 has a drum shape, but may be a sheet shape or an endless belt shape.
As the charging means 312, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used.
As the transfer means 316, the above charger can be generally used, but a combination of a transfer charger and a separation charger is effective.
Reference numeral 313 denotes exposure means, and a semiconductor laser (LD), a light emitting diode (LED), or the like can be used. In some cases, various filters such as sharp cut filters, band pass filters, near infrared cut filters, dichroic filters, interference filters, and color temperature conversion filters may be used to irradiate only light in a desired wavelength range. it can.
Reference numeral 301 denotes a static elimination unit, which is used according to necessity. Examples of the light source include fluorescent materials, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescence (ELs) and the like.
The toner 315 developed on the photoconductor by the developing unit 314 is transferred to the recording medium 318, but not all is transferred, and toner remaining on the photoconductor is also generated. Such toner is removed from the photoreceptor by the cleaning unit 317. As the cleaning means, a rubber cleaning blade, a brush such as a fur brush, a mag fur brush, or the like can be used.
When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. When this is developed with negative (positive) polarity toner (electrodetection fine particles), a positive image can be obtained, and when developed with positive (negative) polarity toner, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

FIG. 4 shows an example for explaining another example of the image forming apparatus according to the present invention. In FIG. 4, a photoconductor 311 is an electrophotographic photoconductor that satisfies the requirements of the present invention, and has an endless belt shape.
Driven by the driving unit 302, charged by the charging unit 312, image exposure by the exposure unit 313, development (not shown), transfer by the transfer unit 316, exposure before cleaning by the exposure unit 303 before cleaning, cleaning by the cleaning unit 317, charge removal The charge removal by means 301 is repeated. In FIG. 4, light irradiation for pre-cleaning exposure is performed from the support side of the photoreceptor (in this case, the support is translucent).
Also in the exposure means 313 of FIG. 4, a semiconductor laser (LD), a light emitting diode (LED), or the like can be used as a light source. In some cases, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. .

The above image forming apparatus exemplifies an embodiment of the present invention, and other embodiments are possible. For example, in FIG. 4, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and neutralization light irradiation may be performed from the support side. On the other hand, in the light irradiation process, image exposure, pre-cleaning exposure, and static elimination exposure are illustrated, but other pre-exposure exposure, pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.
The image forming apparatus may be fixedly incorporated in a copying machine, a facsimile machine, or a printer, but may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many types of process cartridges. These process cartridges are detachable, and maintenance is easy.

As the process cartridge, for example, as shown in FIG. 9, the photosensitive member 101 is incorporated, and includes a charging unit 102, a developing unit 104, a transfer unit 108, and a cleaning unit 107, and further includes other units as necessary. Do it. In FIG. 9, reference numeral 103 denotes exposure by exposure means, and 105 denotes a recording medium.
As the photoreceptor 101, the same one as described above can be used. An arbitrary charging member is used for the charging means 102.
The image forming process using the process cartridge shown in FIG. 9 will be described. The photosensitive member 101 corresponds to an exposure image on its surface by charging by the charging unit 102 and exposure 103 by the exposure unit (not shown) while rotating in the direction of the arrow. An electrostatic latent image is formed. The electrostatic latent image is developed with toner by the developing unit 104, and the toner development is transferred to the recording medium 105 by the transfer unit 108 and printed out. Next, the surface of the photoconductor after the image transfer is cleaned by the cleaning unit 107 and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

Next, a tandem type image forming apparatus that performs the image forming method of the present invention using the image forming apparatus of the present invention will be described.
The tandem type image forming apparatus has a plurality of image forming elements including at least an electrostatic latent image carrier, a charging unit, a developing unit, and a transfer unit. In this tandem type image forming apparatus, four image forming elements for yellow, magenta, cyan, and black are mounted, and each visible image is created in parallel by the four image forming elements, and is recorded on a recording medium or an intermediate transfer member. Therefore, a full color image can be formed at a higher speed.

  As the tandem type image forming apparatus, (1) as shown in FIG. 5, the surface moves so as to pass through a transfer position that is a region facing each electrostatic latent image carrier 1 of a plurality of image forming elements. A direct transfer system in which the visible image formed on each electrostatic latent image carrier 1 is sequentially transferred to the recording medium S by the transfer means 2, and (2) a plurality of images as shown in FIG. The visible image on each electrostatic latent image carrier 1 of the forming element is once transferred sequentially to the intermediate transfer body 4 by the transfer means (primary transfer means) 2, and then the image on the intermediate transfer body 4 is transferred to the secondary transfer means 5. There is an indirect transfer method in which the image is transferred to the recording medium S at once. In FIG. 6, a transfer conveyance belt is used as the secondary transfer unit, but a roller shape may be used.

Comparing the direct transfer method (1) and the indirect transfer method (2), the direct transfer method (1) is a tandem type image forming unit T in which the electrostatic latent image carriers 1 are arranged. A sheet feeding device 6 must be disposed on the upstream side, and a fixing device 7 as a fixing unit must be disposed on the downstream side, which increases the size of the recording medium in the conveyance direction. On the other hand, in the indirect transfer method (2), the secondary transfer position can be set relatively freely, and the paper feeding device 6 and the fixing device 7 are arranged so as to overlap the tandem type image forming unit T. There is an advantage that downsizing is possible.
In the direct transfer method (1), the fixing device 7 is disposed close to the tandem image forming unit T in order not to increase the size in the recording medium conveyance direction. Therefore, the fixing device 7 cannot be disposed with a sufficient margin that the recording medium S can bend, and an impact when the leading end of the recording medium S enters the fixing device 7 (particularly with a thick recording medium). In addition, the fixing device 7 tends to affect upstream image formation due to the speed difference between the recording medium conveyance speed when passing through the fixing device 7 and the recording medium conveyance speed by the transfer conveyance belt. On the other hand, in the indirect transfer method (2), the fixing device 7 can be arranged with a sufficient margin that the recording medium S can be bent, and therefore the fixing device 7 hardly affects the image formation.
For these reasons, indirect transfer systems have recently attracted attention. In this type of color image forming apparatus, as shown in FIG. 6, the transfer residual toner remaining on the electrostatic latent image carrier 1 after the primary transfer is removed by a cleaning device 8 serving as a cleaning unit, and the electrostatic latent image is thus removed. The surface of the carrier 1 is cleaned to prepare for the image formation again. Further, the transfer residual toner remaining on the intermediate transfer body 4 after the secondary transfer is removed by the intermediate transfer body cleaning device 9 to clean the surface of the intermediate transfer body 4 to prepare for image formation again.

The tandem image forming apparatus shown in FIG. 7 is a tandem 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. 7. 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 member 50 stretched between the support roller 14 and the support roller 15 is a tandem type in which four image forming units 18 of yellow, cyan, magenta, and black are arranged to face 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 recording medium conveyed on the secondary transfer belt 24 and the intermediate transfer member 50 are in contact with each other. Is possible. A fixing device 25 is disposed in the vicinity of the secondary transfer device 22.
Note that a sheet reversing device 28 for reversing the recording medium in order to form an image on both sides of the recording medium 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.

  The black, yellow, magenta, and cyan image information is obtained from each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image forming unit) in the tandem developing device 120. Each image forming unit 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 developing device 120 is respectively shown in FIG. Electrostatic latent image carrier 10 (black electrostatic latent image carrier 10K, yellow electrostatic latent image carrier 10Y, magenta electrostatic latent image carrier 10M, and cyan electrostatic latent image carrier 10C); The electrostatic latent image carrier is uniformly charged, and the electrostatic latent image carrier is exposed (L in FIG. 8) for each color image corresponding to each color image information. An exposure device (not shown) for forming an electrostatic latent image corresponding to each color image on the photoconductor, and each color toner (black toner, yellow toner, magenta toner, and cyan toner) on the electrostatic latent image. Develop with A developing device 61 for forming a toner image with each color toner, a transfer charger 62 for transferring the toner image onto the intermediate transfer member 50, a cleaning device 63, and a charge eliminating device 64 are provided. Each single color image (black image, yellow image, magenta image, and cyan image) can be formed based on the color image information. The black image, the yellow image, the magenta image, and the cyan image formed in this way are respectively transferred to the black electrostatic latent image carrier 10K on the intermediate transfer member 50 that is rotationally moved by the support rollers 14, 15, and 16. Black image formed on top, yellow image formed on electrostatic latent image carrier 10Y for yellow, magenta image formed on electrostatic latent image carrier 10M for magenta, and electrostatic latent image carrier for cyan The cyan image formed on the body 10C is sequentially transferred (primary transfer). 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 the recording medium from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, and one sheet at a time by the separation roller 145. The paper 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 to stop. Alternatively, the sheet feeding roller 142 is rotated to feed out the recording medium on the manual feed tray 54, separated one by one by the separation roller 145, put into the manual sheet 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 time with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and the recording medium is sent between the intermediate transfer member 50 and the secondary transfer device 22. Then, by transferring (secondary transfer) the composite color image (color transfer image) onto the recording medium by the secondary transfer device 22, a color image is transferred and formed on the recording medium. The residual toner on the intermediate transfer member 50 after image transfer is cleaned by the intermediate transfer member cleaning device 17.

  The recording medium 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 transfer image) is generated by heat and pressure. ) Is fixed on the recording medium. Thereafter, the recording medium is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the paper discharge tray 57. Alternatively, the recording medium is switched by the switching claw 55 and reversed by the sheet reversing device 28 to return to the transfer position. After guiding and recording an image on the back side, the image is discharged by the discharge roller 56 and stacked on the discharge tray 57.

  In the image forming method and the image forming apparatus of the present invention, a tandem type image having a plurality of image forming elements each having an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, and a transfer unit. Since the electrostatic latent image carrier having the photosensitive layer containing the charge transporting material represented by the structural formula (1) is used as a forming apparatus, it is highly durable and has a quality for repeated use. A stable full-color image can be formed, and a high-speed full-color image can be formed at low cost.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to a following example. In the following examples, “part” represents “part by mass”, and “%” represents “% by mass”.

( Reference Example 1)
<Preparation of electrostatic latent image carrier>
First, an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were prepared.
(Preparation of undercoat layer coating solution)
The following composition was ball milled for 5 days in a ball mill apparatus (using an alumina ball having a diameter of 10 mm as a medium) to prepare an undercoat layer coating solution.
・ Alkyd resin (Beckosol M-6401-50, manufactured by Dainippon Ink & Chemicals, Inc.) ... 10 parts Melamine resin (Super Becamine L-121-60, manufactured by Dainippon Ink & Chemicals, Inc.) ... 7 parts ・ Titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) 48 parts ・ Methyl ethyl ketone 155 parts

(Preparation of charge generation layer coating solution)
The following composition was ball milled for 40 minutes with a bead mill disperser (PSZ balls having a diameter of 0.5 mm as media) to prepare a charge generation layer coating solution.
・ Metal-free phthalocyanine pigment (Dainippon Ink Industries, Ltd., Fastogen Blue 8120B) 14 parts ・ Polyvinyl butyral (Sekisui Chemical Co., Ltd., BX-1) 9 parts ・ Cyclohexanone 270 parts

(Preparation of charge transport layer coating solution)
The following composition was stirred and dissolved to prepare a charge transport layer coating solution.
-Charge transport material represented by the following structural formula (A): 9 parts
However, in the structural formula (A), Me represents a methyl group.
・ Polycarbonate resin (Z polycarbonate, viscosity average molecular weight: 40,000, manufactured by Teijin Chemicals Ltd.) ... 10 parts ・ Tetrahydrofuran: 120 parts ・ 1% silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) ... 1 copy

Next, on the aluminum drum having a diameter of 30 mm and a length of 340 mm, the undercoat layer coating solution, the charge generation layer coating solution, and the charge transport layer coating solution are sequentially applied by a dip coating method. Dried at 135 ° C. for 20 minutes, 80 ° C. for 15 minutes, and 120 ° C. for 20 minutes, respectively, the undercoat layer is 4.5 μm thick, the charge generation layer is 0.15 μm thick, and the charge transport layer is 22.1 μm thick. The electrostatic latent image carrier of Reference Example 1 was produced by forming each film under the ascending / descending speed conditions.

<Image formation>
A tandem type full-color electrophotographic apparatus (IPSiO CX8200, manufactured by Ricoh Co., Ltd.) in which the electrostatic latent image carrier produced as described above is provided with four image forming elements for each color of black, yellow, magenta, and cyan. (The power pack was changed for positive charging and further changed to an LD with a writing wavelength of 780 nm). As the toner, a trial toner having a volume average particle diameter of 6 μm was used.
Using this image forming apparatus, as a durability test, a total of 10,000 full-color mixed images each having an image density of 5% for black, yellow, magenta, and cyan were printed.
As a charging unit of the image forming apparatus, a charging roller disposed in contact with the electrostatic latent image carrier is used.

<Evaluation>
For the DC component, the applied voltage was set so that the initial charging potential of the electrostatic latent image carrier was +500 V at the start of the test, and the test was performed under this charging condition until the end of the test. The developing bias was + 350V. The test environment was 23 ° C. and 60% RH.
At the start of the test (initial stage) and at the end of output of 10,000 images, the photosensitive member surface potential of the exposed area during full writing (exposure) and the image quality of the output image were evaluated. The results are shown in Table 1.
The image quality was evaluated for the presence or absence of changes in color tone (tone), background stain, image density, blurring, etc., depending on the output image. The presence or absence of abnormality and the rank evaluation of the image quality were visually observed, and the determination was made in the following five stages.
〔Evaluation criteria〕
5: Image abnormality is not observed at all, and it is good. 4: Compared with the original image, a slight difference in color tone, image density, background stain, etc. is observed, but it is good without any practical problem. Differences in color tone, image density, background stain, etc. are observed, but this is a level that is not a problem under normal temperature and humidity conditions. 2: There is a slight change in color tone, image density, background stain, etc. 1: Color tone change, density change, dirt on the background is obvious and causes problems

( Reference Example 2)
-Production of electrostatic latent image carrier-
First, 30 parts of a metal-free phthalocyanine pigment (Dainippon Ink Industries, Ltd., Fastogen Blue 8120B) as a charge generation substance and 970 parts of cyclohexanone were dispersed for 2 hours using a ball mill apparatus to obtain a charge generation substance dispersion. Separately, 340 parts of tetrahydrofuran, 49 parts of polycarbonate resin (Z polycarbonate, viscosity average molecular weight 40000, manufactured by Teijin Chemicals Ltd.), 20 parts of the charge transport material represented by the above structural formula (A), the following structure 29.5 parts of the compound represented by the formula (B) and 0.1 part of silicone oil (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved. To this solution, 66.6 parts of the charge generation material dispersion was added and stirred to prepare a photosensitive layer coating solution.

  Next, dip coating was performed on the aluminum drum having a diameter of 30 mm and a length of 340 mm using the photosensitive layer coating solution, and dried at 120 ° C. for 15 minutes to form a photosensitive layer. The photosensitive layer was produced under the ascending / descending speed condition so that the thickness was 22.5 μm.

-Image formation and evaluation-
The electrostatic latent image carrier produced as described above was used for mounting, and then evaluated in the same manner as in Reference Example 1. The results are shown in Table 1.

( Reference Example 3)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 1, except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was changed to titanyl phthalocyanine prepared according to the following Pigment Synthesis Example 1 in Reference Example 1. Formation and evaluation were performed. The results are shown in Table 1.

<Pigment synthesis example 1>
A pigment was prepared according to Japanese Patent Application Laid-Open No. 2001-19871. That is, 29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while keeping the reaction temperature between 170 ° C. and 180 ° C. After the completion of the reaction, the mixture was allowed to cool and then the precipitate was filtered and washed with chloroform until the powder turned blue. Next, it was washed several times with methanol, then washed several times with hot water at 80 ° C. and then dried to obtain crude titanyl phthalocyanine. Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then washed repeatedly with water until the washing solution becomes neutral (ion after washing) The pH value of the exchanged water was 6.8), and a titanyl phthalocyanine pigment wet cake (water paste) was obtained. 40 g of the obtained wet cake (water paste) was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder. This is designated as Pigment 1.

The solid content concentration of the obtained wet cake was 15%. The mass ratio of the crystal conversion solvent to the wet cake was 33 times. In addition, the halide is not used for the raw material of the synthesis example 1.
When the obtained titanyl phthalocyanine powder was measured for X-ray diffraction spectrum under the following conditions, the Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm) was 27.2 ± 0.2 °, and the maximum peak and the minimum angle Titanyl phthalocyanine having a peak at 7.3 ± 0.2 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° A powder was obtained. The measurement results are shown in FIG.
-X-ray diffraction spectrum measurement conditions-
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds The volume average particle size of primary particles in the charge generation layer coating solution using titanyl phthalocyanine was measured with a particle size distribution analyzer (manufactured by Horiba, CAPA-700). .31 μm.

( Reference Example 4)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 2 except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was replaced with titanyl phthalocyanine prepared according to Pigment Synthesis Example 1 of Reference Example 3 in Reference Example 2. Fabricated, imaged and evaluated. The results are shown in Table 1.
The volume average particle size of primary particles in the charge generation material dispersion using this titanyl phthalocyanine was measured by a particle size distribution measuring apparatus (CAPA-700, manufactured by Horiba, Ltd.) and found to be 0.62 μm.

( Reference Example 5)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 1, except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was changed to titanyl phthalocyanine prepared according to the following Pigment Synthesis Example 2 in Reference Example 1. Formation and evaluation were performed. The results are shown in Table 1.

<Pigment synthesis example 2>
According to the method of Pigment Synthesis Example 1, a titanyl phthalocyanine pigment water paste was synthesized, and crystal conversion was performed as follows to synthesize phthalocyanine crystals having smaller primary particles than Pigment Synthesis Example 1.
First, 400 parts of tetrahydrofuran was added to 60 parts of the water paste before crystal conversion obtained in Synthesis Example 1, and the mixture was stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature, and the dark blue color of the paste When the color changed to light blue (20 minutes after the start of stirring), stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filtration device were washed with tetrahydrofuran to obtain a wet cake of pigment. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts of titanyl phthalocyanine crystals. The resulting pigment is designated as Pigment 2. In addition, the halide is not used for the raw material of the pigment synthesis example 2.
The solid content concentration of the obtained wet cake was 15%. The mass ratio of the crystal conversion solvent to the wet cake was 44 times.
It was 0.45 micrometer when the volume average particle diameter of the primary particle in the electric charge generation layer coating liquid using the obtained titanyl phthalocyanine was measured with the particle size distribution measuring apparatus (Horiba, CAPA-700). .

( Reference Example 6)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 2, except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was changed to titanyl phthalocyanine prepared according to Pigment Synthesis Example 2 of Reference Example 5 in Reference Example 2. Fabrication, image formation, and evaluation were performed. The results are shown in Table 1.
The volume average particle size of the primary particles in the charge generation material dispersion using titanyl phthalocyanine was measured by a particle size distribution analyzer (Horiba, CAPA-700) and found to be 0.54 μm.

( Reference Example 7)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 1, except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was changed to titanyl phthalocyanine prepared according to the following pigment synthesis example 3 in Reference Example 1. Formation and evaluation were performed. The results are shown in Table 1.

<Pigment synthesis example 3>
A pigment was prepared according to the method described in Reference Example 1 of JP-A-1-299874 (Patent No. 2512081). That is, the wet cake prepared in Pigment Synthesis Example 1 of Reference Example 3 was dried, 1 g of the dried product was added to 50 g of polyethylene glycol, and sand milling was performed with 100 g of glass beads. After the crystal transition, the mixture was washed successively with dilute sulfuric acid and aqueous ammonium hydroxide and dried to obtain a pigment. This is designated as Pigment 3. In addition, the halide is not used for the raw material of the pigment synthesis example 3.
It was 0.43 micrometer when the volume average particle diameter of the primary particle in the electric charge generation layer coating liquid using the obtained titanyl phthalocyanine was measured with the particle size distribution measuring apparatus (Horiba, CAPA-700). .

( Reference Example 8)
-Production of electrostatic latent image carrier, image formation and evaluation-
An electrostatic latent image carrier was prepared in the same manner as in Reference Example 2 except that the metal-free phthalocyanine pigment (Fastogen Blue 8120B) was replaced with titanyl phthalocyanine prepared according to Pigment Synthesis Example 3 of Reference Example 7 in Reference Example 2. Fabrication, image formation, and evaluation were performed. The results are shown in Table 1.

( Reference Example 9)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 5, an electrostatic latent image was obtained in the same manner as in Reference Example 5 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula (C). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (C), Me represents a methyl group.

( Reference Example 10)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 5, an electrostatic latent image was obtained in the same manner as in Reference Example 5 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula (D). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (D), Me represents a methyl group.

( Reference Example 11)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image was obtained in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) was changed to a charge transport material represented by the following structural formula (C). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (C), Me represents a methyl group.

( Reference Example 12)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image was obtained in the same manner as in Reference Example 6 except that the charge transport material represented by Structural Formula (A) was changed to the charge transport material represented by Structural Formula (D) below. A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (D), Me represents a methyl group.

( Reference Example 13)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image was obtained in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula (E). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (E), the terminal group represents Me (methyl group).

( Reference Example 14)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image was obtained in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula (F). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (F), the terminal group represents Me (methyl group).

( Reference Example 15)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, the electrostatic latent image was changed in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula (G). A carrier was prepared, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in said structural formula (G), a terminal group represents Me (methyl group), n is 1-100, and is a mixture of the thing of these ranges.

(Example 16)
-Production of electrostatic latent image carrier, image formation and evaluation-
Reference Example 6, except that changes the charge transporting material represented by the structural formula (A) to 15 parts from 20 parts, and was added 5 parts of a charge transporting material represented by the following structural formula (H), Reference In the same manner as in Example 6, an electrostatic latent image bearing member was produced, image formation was performed, and evaluation was performed. The results are shown in Table 1.
However, in the structural formula (H), the terminal group represents Me (methyl group).

( Reference Example 17)
-Image formation and evaluation-
After the electrostatic latent image carrier produced in Reference Example 5 was mounted, a tandem full-color image forming apparatus (IPSiO CX400, stock) provided with four image forming elements for each color of black, yellow, magenta, and cyan It was mounted on a remodeling machine (manufactured by Ricoh Co., Ltd.). As the toner, a trial toner having a volume average particle diameter of 6 μm was used.
Using this apparatus, as a durability test, 10,000 full-color mixed images in which the image density of each color of black, yellow, magenta, and cyan was 5% were printed.
As the charging means of the image forming apparatus, a charging roller disposed in contact with the electrostatic latent image carrier is used.

<Evaluation>
For the DC component, the applied voltage was set so that the initial surface potential of the electrostatic latent image carrier was +500 V at the start of the test, and the test was performed under this charging condition until the end of the test. The developing bias was + 350V. The test environment was 23 ° C. and 60% RH. Under such conditions, the potential on the surface of the latent electrostatic image bearing member (exposure portion potential) after exposure (LD entire surface writing), the entire surface writing (at the initial stage) and at the end of 10,000-sheet image output (each The photosensitive member surface potential of the exposed area during exposure) and the image quality of the output image were evaluated. The results are shown in Table 1.
The image quality was evaluated for the presence or absence of color tone (color shade) change, background stain, image density, blurring, and the like due to the output image. The presence / absence of abnormality and the rank evaluation of image quality were visually observed and judged in the following five stages.
〔Evaluation criteria〕
5: Image abnormality is not observed at all, and it is good. 4: Compared with the original image, a slight difference in color tone, image density, background stain, etc. is observed, but it is good without any practical problem. Differences in color tone, image density, background stain, etc. are observed, but this is a level that is not a problem under normal temperature and humidity conditions. 2: There is a slight change in color tone, image density, background stain, etc. 1: Color tone change, density change, dirt on the background is obvious and causes problems

( Reference Example 18)
-Image formation and evaluation-
After for implementing electrostatic image bearing member produced in Reference Example 6, in the same manner as in Reference Example 17, performs image formation was evaluated in the same manner as in Reference Example 17. The results are shown in Table 1.

( Reference Example 19)
The electrostatic latent image carrier used for evaluation in Reference Example 6 and subjected to a 10,000 sheet passing test was taken out, and the concentrations of ozone and nitrogen oxide gas (a gas in which NO and NO ₂ were mixed in equal amounts) were respectively under 5ppm environment, perform left gas exposure test five days, then attached to the same image forming apparatus as in reference example 1 again, in the same manner as in reference example 1, the dark portion potential performs image output, light portion potential The image quality was evaluated in the same manner. The results are shown in Table 2.

(Example 20)
The electrostatic latent image carrier used for evaluation in Example 16 and subjected to a 10,000 sheet passing test was taken out, and the concentrations of ozone and nitrogen oxide gas (a gas in which NO and NO ₂ were mixed in equal amounts) were respectively under 5ppm environment, perform left gas exposure test five days, then attached to the same image forming apparatus as in reference example 1 again, in the same manner as in reference example 1, the dark portion potential performs image output, light portion potential The image quality was evaluated in the same manner. The results are shown in Table 2.

(Comparative Example 1)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 1, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 1, except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.
However, in said structural formula, Me represents a methyl group and t-Bu represents a t-butyl group.

(Comparative Example 2)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 1, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 1, except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.

(Comparative Example 3)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 2, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 2, except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.
However, in said structural formula, Me represents a methyl group and t-Bu represents a t-butyl group.

(Comparative Example 4)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 2, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 2, except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.

(Comparative Example 5)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 5, the latent electrostatic image bearing member was prepared in the same manner as in Reference Example 5 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.
However, in said structural formula, Me represents a methyl group and t-Bu represents a t-butyl group.

(Comparative Example 6)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 5, the latent electrostatic image bearing member was prepared in the same manner as in Reference Example 5 except that the charge transport material represented by the structural formula (A) was changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.

(Comparative Example 7)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.
However, in said structural formula, Me represents a methyl group and t-Bu represents a t-butyl group.

(Comparative Example 8)
-Production of electrostatic latent image carrier, image formation and evaluation-
In Reference Example 6, an electrostatic latent image carrier is prepared in the same manner as in Reference Example 6 except that the charge transport material represented by the structural formula (A) is changed to the charge transport material represented by the following structural formula. Fabrication and image formation were performed, and evaluation was performed in the same manner as in Reference Example 1. The results are shown in Table 1.

From the results of Table 1, Example 16 and Reference Examples 1 to 15, 17, and 18 are extremely high in which abnormal images such as a change in color tone, background stain, and density reduction are not seen as compared with Comparative Examples 1 to 8. It was confirmed that a quality image was obtained.

  The image forming apparatus and the image forming method of the present invention can form a very high-quality full-color image that does not change color tone over a long period of use and that does not show abnormal images such as density reduction and background stains. Therefore, it has excellent practical value when applied to a copying machine, a facsimile, a laser printer, a direct digital plate making machine, and the like.

FIG. 1 is a schematic cross-sectional view showing an example of a single-layer type electrostatic latent image carrier of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of the laminated electrostatic latent image carrier of the present invention. FIG. 3 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 4 is a schematic view showing another example of the image forming apparatus of the present invention. FIG. 5 is a partial schematic view showing an example of the tandem type image forming apparatus of the present invention. FIG. 6 is a partial schematic view showing another example of the tandem type image forming apparatus of the present invention. FIG. 7 is an overall schematic view showing still another example of the tandem type image forming apparatus of the present invention. FIG. 8 is a partially enlarged view of FIG. FIG. 9 is a schematic view showing an example of a process cartridge mounted on the image forming apparatus of the present invention. 10 is an X-ray diffraction spectrum of titanyl phthalocyanine synthesized in Pigment Synthesis Example 1 of Reference Example 3. FIG.

Explanation of symbols

1 Electrostatic latent image carrier (photoconductor)
DESCRIPTION OF SYMBOLS 2 Transfer apparatus 3 Sheet conveyance belt 4 Intermediate transfer body 5 Secondary transfer apparatus 6 Paper feeding apparatus 7 Fixing apparatus 8 Photoconductor cleaning apparatus 9 Intermediate transfer body cleaning apparatus 10 Electrostatic latent image carrier (photosensitive drum)
10K Electrostatic latent image carrier for black 10Y Electrostatic latent image carrier for yellow 10M Electrostatic latent image carrier for magenta 10C Electrostatic latent image carrier for cyan 14 Support roller 15 Support roller 16 Support roller 17 Intermediate transfer cleaning device DESCRIPTION OF SYMBOLS 18 Image forming means 20 Charging roller 21 Exposure apparatus 22 Secondary transfer apparatus 23 Roller 24 Secondary transfer belt 25 Fixing apparatus 26 Fixing belt 27 Pressure roller 28 Sheet reversing apparatus 30 Exposure apparatus 32 Contact glass 33 1st traveling body 34 2nd Traveling body 35 Imaging lens 36 Reading sensor 40 Developer 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 Development low 44Y Developing roller 44M Developing 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 Developer 62 Transfer charger 63 Photoconductor cleaning device 64 Charger 70 Static discharge lamp 80 Transfer roller 90 Cleaning device 95 Transfer paper 100 Image forming device 101 Photoconductor 102 Charging means 103 Exposure 104 Developing means 105 Recording medium 107 Cleaning means 108 Transfer means 110 Belt-type image fixing device 120 Tandem type developer 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separation roller 146 Paper feed path 147 Conveyance roller 148 Paper feed path 150 Copier main body 160 Charging device 200 Paper feed table 201 Support body 202 Photosensitive layer 203 Charge generation layer 204 Charge transport layer 205 Undercoat layer 210 Image fixing apparatus 220 Heating roller 230 Pressure roller 300 Scanner 301 Static elimination means 302 Driving means 311 Photoconductor 312 Charging means 313 Exposure means 314 Development means 316 Transfer means 400 Automatic document feeder (ADF)

Claims (12)

An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image with toner to form a visible image An image forming apparatus in which a plurality of image forming elements having at least developing means and transfer means for transferring the visible image to a recording medium are arranged,
The electrostatic latent image carrier has a support and at least a photosensitive layer on the support, and the photosensitive layer is represented by at least the following structural formula (1) and the following structural formula (2). An image forming apparatus comprising a charge transport material.
However, in the structural formula (1), R ¹ and R ² may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ may be the same as or different from each other. It may have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and a substituent. Represents any of the aralkyl groups that may be present. n is the number of repeating units and represents an integer of 0 to 100.
However, in the structural formula (2), R ¹⁵ and R ¹⁶ may be the same as or different from each other, and each represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. It represents either a cycloalkyl group that may have or an aralkyl group that may have a substituent. R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ may be the same as or different from each other , and have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, or a substituent. Any one of an optionally substituted alkyl group, an optionally substituted cycloalkyl group, and an optionally substituted aralkyl group.   The image forming element has an electrostatic latent image carrier and at least one means selected from a charging means, a developing means, a transfer means, a cleaning means, and a charge eliminating means, and is detachable from the image forming apparatus main body. The image forming apparatus according to claim 1, wherein the image forming apparatus is a process cartridge. The image forming apparatus according to claim 1, wherein the photosensitive layer contains a charge transport material represented by the following structural formula (1-1).
However, in the structural formula (1-1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are represented by the structural formula (1). Represents the same meaning. The image forming apparatus according to claim 1, wherein the photosensitive layer contains a charge transport material represented by the following structural formula (1-2).
However, in the structural formula (1-2), R ¹ and R ² represent the same meaning as in the structural formula (1). The image forming apparatus according to claim 1, wherein the photosensitive layer contains a charge generating substance, and the charge generating substance is phthalocyanine. The image forming apparatus according to claim 5, wherein the charge generation material is titanyl phthalocyanine. The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, 9.4 °, 9 The main peak at .6 ° and 24.0 °, and the diffraction peak at the lowest angle side at 7.3 °, the peak at 7.3 ° and the peak at 9.4 ° The image forming apparatus according to claim 6, wherein there is no peak between the peaks. The image forming apparatus according to claim 6, wherein the primary particles of titanyl phthalocyanine have a volume average particle size of 0.60 μm or less. 9. The image forming apparatus according to claim 1, wherein the photosensitive layer has a single layer structure. 9. The image forming apparatus according to claim 1, wherein the photosensitive layer has a laminated structure having a charge generation layer containing at least a charge generation material and a charge transport layer containing at least a charge transport material. The image forming apparatus has an intermediate transfer body on which a visible image formed on the electrostatic latent image carrier is primarily transferred, and a transfer for secondary transfer of the visible image carried on the intermediate transfer body to a recording medium. 11. A plurality of color toner images are sequentially superimposed on the intermediate transfer member to form a color image, and the color image is secondarily transferred collectively onto the recording medium. The image forming apparatus according to any one of the above. An electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image with toner to form a visible image An image forming method using an image forming apparatus in which a plurality of image forming elements having at least developing means and transfer means for transferring the visible image to a recording medium are arranged,
The electrostatic latent image carrier has a support and at least a photosensitive layer on the support, and the photosensitive layer is represented by at least the following structural formula (1) and the following structural formula (2). An image forming method comprising: a charge transport material.
However, in the structural formula (1), R ¹ And R ² May be the same as or different from each other, have a hydrogen atom, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, and a substituent. Represents any of the aralkyl groups that may be present. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ And R ¹⁴ May be the same as or different from each other, and have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group or a substituent. Represents either an optionally substituted cycloalkyl group or an optionally substituted aralkyl group. n is the number of repetitions and represents an integer of 0 to 100.
However, in the structural formula (2), R ¹⁵ And R ¹⁶ May be the same as or different from each other, have a hydrogen atom, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, and a substituent. Represents any of the aralkyl groups that may be present. R ¹⁷ , R ¹⁸ , R ¹⁹ And R ²⁰ May be the same as or different from each other, and have a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an optionally substituted alkyl group or a substituent. Represents either an optionally substituted cycloalkyl group or an optionally substituted aralkyl group.