JP2006091488A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having no destaticizing mechanism, and that suppresses generation of exposure memory and gives sharp images over a long time. <P>SOLUTION: The image forming apparatus having no destaticizing mechanism contains an amine stilbene derivative expressed by general Formula (1) as a hole transport agent of an electrophotographic photoreceptor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a static elimination-less type image forming apparatus, and more particularly to an image forming apparatus provided with an electrophotographic photosensitive member with a small exposure memory by using a specific hole transport agent.

Conventionally, as an electrophotographic photosensitive member used in an image forming apparatus, an organic photosensitive material composed of an organic photosensitive material such as a charge transporting agent (hole transporting agent, electron transporting agent), a charge generating agent, and a binder resin (binder resin). The body is used. Such an organic photoreceptor is advantageous in that it is easy to manufacture and has a wide degree of freedom in structural design because it has various options for the photoreceptor material as compared with conventional inorganic photoreceptors.
Among such organic photoreceptor materials, an electrophotographic photoreceptor using a stilbene derivative represented by the following general formula (29) is known as a charge transfer agent having a predetermined charge mobility (for example, patents). Reference 1).

(In the general formula (29), R ²¹ and R ²² are a hydrogen atom, a halogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, an aryl group, or an amino group, and R ¹⁷ , R ¹⁸ , R ¹⁹ And at least two of R ²⁰ represent general formula (30), and among R ¹⁷ , R ¹⁸ , R ^19, and R ²⁰ , when they are not groups represented by general formula (30), they represent a hydrogen atom. .)

(In the general formula (30), R ²³ represents a hydrogen atom, a substituted or unsubstituted alkyl group or an aryl group, and R ²⁴ and R ²⁵ each independently represents a hydrogen atom, or a substituted or unsubstituted alkyl group. A group or an aryl group, at least one of R ²⁴ and R ²⁵ represents a substituted or unsubstituted aryl group.)

In Patent Document 2, a photosensitive layer is formed on a conductive substrate, and the photosensitive layer contains a phthalocyanine compound as a charge generating agent, a hole transporting agent, and an electron transporting agent in a binder resin. The content of the compound is 0.1 to 4% by weight based on the weight of the binder resin, the film thickness of the photosensitive layer is 10 to 35 μm, the exposure wavelength is 780 nm, and the exposure energy is 1.0 μJ / cm ² . An image forming apparatus having no static elimination system using a single layer type electrophotographic photosensitive member, characterized in that the measured absolute value difference between positive polarity and negative polarity sensitivity is 500 V or less is disclosed.
JP-A-7-36203 (Claims) JP 2001-312075 (Claims)

However, the electrophotographic photosensitive member containing the stilbene derivative described in Patent Document 1 is mainly considered for use in a laminated electrophotographic photosensitive member, and therefore, evaluation of initial and environmental characteristics of the laminated electrophotographic photosensitive member. However, it has not been evaluated as a single-layer electrophotographic photosensitive member. Here, in the single-layer type electrophotographic photosensitive member, internal charges easily accumulate in the photosensitive layer, so it is difficult to suppress the occurrence of exposure memory in a static elimination-less type image forming apparatus using the single-layer type electrophotographic photosensitive member. It was thought to be. Therefore, it has not been studied to apply the single layer type electrophotographic photosensitive member containing the stilbene derivative described in Patent Document 1 to an image forming apparatus of a static elimination-less type.
In addition, the stilbene derivative specifically described in Patent Document 2 has a wide conjugate plane and can increase charge mobility, but there is no substituent containing a vinyl group in the triphenylamine structure at the molecular end. The compatibility with other constituent materials was insufficient. Therefore, there has been a problem in that charge transfer within the photoreceptor is not performed efficiently, internal charges tend to remain, and erasure of the exposure memory is insufficient.

Therefore, the present inventors have found the fact that the occurrence of exposure memory can be suppressed by using a specific stilbene derivative as a hole transporting agent for the single-layer electrophotographic photoreceptor of the image forming apparatus. The invention has been completed.
That is, an object of the present invention is to provide a static elimination-less type image forming apparatus capable of suppressing generation of an exposure memory and obtaining a clear image for a long time.

  According to the present invention, a charging unit, an exposing unit, a developing unit, and a transfer unit are arranged around a single layer type electrophotographic photosensitive member. The body includes a photosensitive layer composed of at least a charge generator, a hole transport agent, and a binder resin on a support substrate, and contains an amine stilbene derivative represented by the following general formula (1) as a hole transport agent. As a result, the above-described problem can be solved.

(In General Formula (1), A to D and R ^{1 to} R ¹⁴ are each an independent substituent, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and 1 carbon atom. A substituted or unsubstituted halogenated alkyl group having -20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted amino group, or , R ^{2 to} R ⁶ and any two of R ^{9 to} R ¹³ are carbocyclic structures formed by bonding or condensation, and the repeating numbers a to d are each independently 0 to 0. The integer of 4, m, and n are each independently an integer of 0-3.)

  In constituting the image forming apparatus of the present invention, at least two of A, B, C and D in the general formula (1) as the hole transport agent of the electrophotographic photosensitive member provided have 6 to 6 carbon atoms. Preferably it is 15 substituted or unsubstituted aryl groups.

In constituting the image forming apparatus of the present invention, as a hole transport agent of the electrophotographic photosensitive member provided, at least two of R ^{2 to} R ^{6 in} the general formula (1) and / or R ⁹ to At least two of R ¹³ are substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 10 carbon atoms, or bonded or condensed carbocyclic structures having 3 to 7 carbon atoms. It is preferable that

Further, in constituting the image forming apparatus of the present invention, R ² , R ⁶ , R ⁹ and R ^{13 in} the general formula (1) are those having 1 to 1 carbon atoms as the hole transport agent of the electrophotographic photoreceptor provided. It is preferably a substituted or unsubstituted alkyl group having 6 or a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms.

  Further, in configuring the image forming apparatus of the present invention, the amount of the hole transport agent added to the electrophotographic photosensitive member provided is a value within the range of 60 to 100 parts by weight with respect to 100 parts by weight of the binder resin. It is preferable to do.

  Further, in configuring the image forming apparatus of the present invention, a cleaningless type image forming apparatus is preferable.

  In constituting the image forming apparatus of the present invention, it is preferable that the electrophotographic photosensitive member is provided as a unitized process cartridge.

According to the image forming apparatus of the present invention, the amine stilbene derivative represented by the general formula (1) is included as the hole transport agent of the single layer type electrophotographic photosensitive member provided in the image forming apparatus, thereby It is possible to provide a static elimination-less type image forming apparatus that is less likely to occur and can obtain a clear image over a long period of time.
That is, since the amine stilbene derivative represented by the general formula (1) introduces a vinyl group having a predetermined substituent into the triphenylamine structure at the molecular end, steric hindrance occurs. Compatibility and solubility in a solvent can be improved.
Therefore, by using such an amine stilbene derivative as a hole transport agent in an electrophotographic photoreceptor, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and excellent sensitivity characteristics and charging characteristics can be obtained. Therefore, since the memory potential is lowered, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.
Further, since the image forming apparatus of the present invention is a static elimination-less type, there is no possibility that the photosensitive member is deteriorated by the static elimination means, and therefore a clear image can be provided over a long period of time.

Further, according to the image forming apparatus of the present invention, at least two of A, B, C and D in the general formula (1) are carbon as the hole transport agent of the electrophotographic photoreceptor provided in the image forming apparatus. By being a substituted or unsubstituted aryl group of several 6 to 15, intramolecular conjugation spreads and charge mobility can be increased.
Therefore, by using such an amine stilbene derivative as a hole transport agent in an electrophotographic photoreceptor, an electrophotographic photoreceptor having more excellent sensitivity characteristics and charging characteristics can be provided. Therefore, it is possible to provide a static elimination-less type image forming apparatus capable of suppressing the occurrence of the above and obtaining a clear image.
In addition, since such a hole transport agent can be produced with a relatively high yield, the manufacturing cost of the electrophotographic photosensitive member, and hence the manufacturing cost of the image forming apparatus can be reduced.

In addition, according to the image forming apparatus of the present invention, as a hole transport agent of the electrophotographic photosensitive member provided in the image forming apparatus, at least two of R ^{2 to} R ^{6 in} the general formula (1) and / or When at least two of R ^{9 to} R ¹³ are predetermined substituents, the compatibility with the binder resin and the solubility in the solvent can be improved, the charge mobility is increased, and crystallization is improved. It can be prevented more effectively.
Therefore, since an amine stilbene derivative having such a substituent can be used as a hole transport agent in an electrophotographic photoreceptor, an electrophotographic photoreceptor having more excellent sensitivity characteristics and charging characteristics can be provided. Therefore, it is possible to provide a static elimination-less type image forming apparatus that can suppress the generation of exposure memory and obtain a clear image.

Further, according to the image forming apparatus of the present invention, R ² , R ⁶ , R ⁹ and R ^{13 in} the general formula (1) are predetermined as the hole transport agent of the electrophotographic photosensitive member provided in the image forming apparatus. By being a substituent, the compatibility with the binder resin and the solubility with respect to the solvent can be further improved, the charge mobility can be increased, and crystallization can be more effectively prevented.
Therefore, since an amine stilbene derivative having such a substituent can be used as a hole transport agent in an electrophotographic photoreceptor, an electrophotographic photoreceptor having more excellent sensitivity characteristics and charging characteristics can be provided. Therefore, it is possible to provide a static elimination-less type image forming apparatus that can suppress the generation of exposure memory and obtain a clear image.

Further, according to the image forming apparatus of the present invention, crystallization of the hole transport agent can be effectively prevented by limiting the amount of the hole transport agent added to the electrophotographic photosensitive member to a value within a predetermined range. .
Therefore, since an amine stilbene derivative having such a substituent can be used as a hole transport agent in an electrophotographic photoreceptor, an electrophotographic photoreceptor having more excellent sensitivity characteristics and charging characteristics can be provided. Therefore, it is possible to provide a static elimination-less type image forming apparatus that can suppress the generation of exposure memory and obtain a clear image.

Further, according to the image forming apparatus of the present invention, the cleaner-less type can simplify the structure, prevent mechanical damage due to the cleaner operation of the electrophotographic photosensitive member, and further clarify for a long period of time. Images can be provided.
In other words, since the electrophotographic photosensitive member is not worn by the cleaning device, the sensitivity of the electrophotographic photosensitive member can be maintained for a long period of time, and thus a static elimination-less type image forming apparatus capable of obtaining a clear image for a longer period of time is provided. can do.

Further, according to the image forming apparatus of the present invention, since the electrophotographic photosensitive member is provided as a unitized process cartridge, handling is further facilitated.
That is, when the sensitivity characteristics and the like of the electrophotographic photosensitive member are deteriorated, the electrophotographic photosensitive member can be easily and quickly replaced as a process cartridge.

  Hereinafter, an example of an embodiment relating to an image forming apparatus of the present invention will be specifically described with reference to the drawings as appropriate.

[First embodiment]
The first embodiment is a static elimination-less type image forming apparatus in which a charging unit, an exposure unit, a developing unit, and a transfer unit are arranged around a single layer type electrophotographic photosensitive member. As a photographic photoreceptor, an amine stilbene derivative represented by the following general formula (1) is provided on a support substrate with a photosensitive layer composed of at least a charge generator, a hole transport agent, and a binder resin. An image forming apparatus comprising:
In general formula (1), A to D, R ^{1 to} R ¹⁴ , a to d, m, and n are the same as described above.

1. Schematic Configuration Here, FIG. 1 shows a schematic configuration of an example of an embodiment of the image forming apparatus of the present invention.
That is, as shown in FIG. 1, the image forming apparatus 7 of this example includes an electrophotographic photosensitive member 1 (hereinafter sometimes simply referred to as a photosensitive member) and around the electrophotographic photosensitive member 1. , Charger 2 for carrying out the charging process, exposure light source 3 for carrying out the exposure process, developer 4 for carrying out the developing process, transfer machine 5 for carrying out the transferring process, and collecting paper dust It is preferable that a cleaning brush 6 is provided.
Further, the image forming apparatus shown in FIG. 1 does not have to be substantially provided with a static eliminator for performing the static elimination process. For example, if the static elimination process can be controlled on / off as desired, the image forming apparatus can be removed. Even when an electric device is provided, it can be included in the image forming apparatus of the present invention.

In the photoreceptor 1, by using a specific amine stilbene derivative as a hole transport agent, the charge mobility of the photoreceptor becomes high and uniform, and the sensitivity characteristics are excellent, so that static elimination is not performed after exposure. However, the occurrence of exposure memory in the charging process can be suppressed.
Furthermore, in the case of the image forming apparatus 7 of the present invention that does not require static elimination, it is also preferable to provide a so-called cleanerless type image forming apparatus without providing the image forming apparatus 7 with a cleaning blade (not shown) in order to further reduce the size.
More specifically, the image forming apparatus in the present invention is typically a copying machine, a laser beam printer, a CRT printer, a printer such as an LED printer, a liquid crystal printer, or a laser plate making.

2. Operation The image forming operation of the image forming apparatus 7 of the present invention with no static elimination is performed as follows. That is, as shown in FIG. 1, the photoconductor 1 rotates at a constant speed in the direction of the arrow, and the electrophotographic process is performed on the surface of the photoconductor 1 in the following order.
More specifically, the charger 1 charges the entire surface of the photoreceptor 1, and then the print pattern is exposed by the exposure light source 3. Next, the developing device 4 develops the toner corresponding to the print pattern, and the transfer device 5 transfers the toner to a transfer material (paper) (not shown). Finally, excess paper dust remaining on the photoreceptor 1 is removed by the cleaning device 6.

3. Electrophotographic Photoreceptor Further, the image forming apparatus of the present invention includes a single layer type electrophotographic photosensitive member.
The reason for this is that it can be used for both positive and negative chargeability, has a simple structure and is easy to manufacture, and can suppress film defects when forming a photoreceptor layer. It is because it can improve.

3-1 Single-layer Type Photoreceptor (1) Basic Configuration As shown in FIG. 2A, the single-layer type photoreceptor 10 has a single photoreceptor layer 14 provided on a conductive substrate 12. is there.
This photoreceptor layer includes, for example, an amine stilbene derivative (hole transporting agent) represented by the general formula (1), a charge generating agent, a binder resin, and an electron transporting agent, a leveling agent and the like as necessary. Is dissolved or dispersed in a suitable solvent, and the resulting coating solution is applied onto a conductive substrate and dried. Such a single layer type photoreceptor is characterized in that it can be applied to either a positive or negative charge type with a single configuration, has a simple layer configuration, and is excellent in productivity.

Further, since the obtained single-layer type photoreceptor contains the amine stilbene derivative represented by the general formula (1), the residual potential is lowered and it has a predetermined sensitivity. .
Furthermore, when an electron transport agent is included in the photoreceptor layer of a single-layer type photoreceptor, electrons are efficiently exchanged between the charge generator and the hole transport agent, and the sensitivity and the like are more stable. The tendency to do is seen.
In addition, as shown in FIG. 2B, a barrier layer 16 is formed between the conductive substrate 12 and the photoreceptor layer 14 in a range that does not impair the characteristics of the photoreceptor, as shown in FIG. The single-layer type photoreceptor 10 ′ may be used. Further, as shown in FIG. 2C, a single layer type photoreceptor 10 ″ in which a protective layer 18 may be formed on the surface of the photoreceptor layer 14 may be used.

(2) Hole transport agent (2) -1 type As a hole transport agent, an amine stilbene derivative represented by the general formula (1) is contained.
The reason for this is that the use of an amine stilbene derivative in which a vinyl group having a substituent is introduced into triphenylamine at the molecular terminal as a hole transporting agent causes steric hindrance. This is because solubility and solubility in a solvent can be improved.
Therefore, by using such an amine stilbene derivative as a charge transporting agent (hole transporting agent) in an electrophotographic photosensitive member, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and has excellent sensitivity. Since the electrophotographic photosensitive member having the characteristics and the charging characteristics can be provided, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.
In addition, by using an amine stilbene derivative having a specific structure introduced at the molecular end, not only the sensitivity characteristics can be further improved, but also the mechanical characteristics and film formability can be improved. Since it is possible to provide an electrophotographic photosensitive member that can maintain sensitivity characteristics, it is possible to provide a static elimination-less type image forming apparatus that can obtain a clear image over a long period of time.

Moreover, it is preferable that at least two of A to D of the amine stilbene derivative are substituted or unsubstituted aryl groups having 6 to 15 carbon atoms, and more specifically, represented by the following general formula (2). More preferred are amine stilbene derivatives.
This is because the amine stilbene derivative as a hole transporting agent has a structure represented by the following general formula (2), so that intramolecular conjugation spreads evenly at both ends, and charge mobility can be further increased. In addition, such a structure is relatively easy to introduce, so that a predetermined amine stilbene derivative can be produced in a relatively high yield.
Therefore, by using such an amine stilbene derivative as a charge transporting agent (hole transporting agent) in an electrophotographic photosensitive member, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and has excellent sensitivity. Since the electrophotographic photosensitive member having the characteristics and the charging characteristics can be provided, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

(In General Formula (2), B, D, R ^{1 to} R ¹⁴ , a to d, m and n are B, D, R ^{1 to} R ¹⁴ , a to d, m and n in General Formula (1). The same contents as n, wherein R ¹⁵ and R ¹⁶ are each an independent substituent, a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted group having 1 to 20 carbon atoms. Or an unsubstituted halogenated alkyl group, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted amino group, or a plurality of R Any two of ¹⁵ and R ¹⁶ are carbocyclic structures formed by bonding or condensation, and the repeating numbers e and f are each independently an integer of 0 to 4).

In addition, at least two of R ^{2 to} R ⁶ and / or at least two of R ^{9 to} R ¹³ of the amine stilbene derivative are each a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or 1 carbon atom. It is preferably a substituted or unsubstituted alkoxy group having 10 to 10 carbon atoms, or a carbocyclic structure having 3 to 7 carbon atoms bonded or condensed. Furthermore, at least two of R ^{2 to} R ⁶ described above and / or at least two of R ^{9 to} R ¹³ are substituted or unsubstituted alkyl groups having 1 to 6 carbon atoms, substituted with 1 to 6 carbon atoms. Alternatively, it is more preferably an unsubstituted alkoxy group, or a bonded or condensed carbocyclic structure having 4 to 5 carbon atoms.
This is because the compatibility with the binder resin and the solubility in the solvent can be improved, the charge mobility can be increased, and crystallization can be more effectively prevented.
Therefore, by using such an amine stilbene derivative as a charge transporting agent (hole transporting agent) in an electrophotographic photosensitive member, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and has excellent sensitivity. Since the electrophotographic photosensitive member having the characteristics and the charging characteristics can be provided, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

In addition, R ² , R ⁶ , R ⁹ and R ^{13 of} such an amine stilbene derivative are a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms. Is preferred.
This is because the compatibility with the binder resin and the solubility in the solvent can be improved, the charge mobility can be increased, and crystallization can be more effectively prevented.
Therefore, by using such an amine stilbene derivative as a charge transporting agent (hole transporting agent) in an electrophotographic photosensitive member, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and has excellent sensitivity. Since the electrophotographic photosensitive member having the characteristics and the charging characteristics can be provided, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

In addition, the hole mobility of such an amine stilbene derivative is preferably 1.0 × 10 ⁻⁴ cm ² / V · sec or more.
This is because it can be estimated that the hole mobility of such an amine stilbene derivative is a certain value or more, so that an electrophotographic photoreceptor containing such an amine stilbene derivative can maintain high sensitivity characteristics. is there.
Therefore, by using such an amine stilbene derivative as a charge transporting agent (hole transporting agent) in an electrophotographic photosensitive member, such an amine stilbene derivative can be uniformly dispersed in the photosensitive layer, and has excellent sensitivity. Since the electrophotographic photosensitive member having the characteristics and the charging characteristics can be provided, it is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

(2) -2 Specific Example As specific examples of the amine stilbene derivative represented by the general formula (1), amine stilbene derivatives (HTM-A to K) represented by the following structural formulas (3) to (13) are shown. .

  It is also preferable to use a conventionally known hole transport agent in combination. Examples of such hole transporting agents include N, N, N ′, N′-tetraphenylbenzidine derivatives, N, N, N ′, N′-tetraphenylphenylenediamine derivatives, N, N, N ′, N ′. -Tetraphenylnaphthylenediamine derivatives, N, N, N ', N'-tetraphenylphenanthrylenediamine derivatives, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, etc. Oxadiazole compounds, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazolines such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline Compounds, hydrazone compounds, indole compounds, oxazole compounds, isoxazols System compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and nitrogen-containing cyclic compounds such as triazole compounds, and condensed polycyclic compounds.

(2) -3 Addition amount Further, the addition amount of the hole transport agent is preferably set to a value within the range of 60 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the hole transport agent is less than 60 parts by weight, the sensitivity is lowered, which may cause practical problems. On the other hand, when the added amount of the hole transport agent exceeds 100 parts by weight, the hole transport agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.
Therefore, it is more preferable to set the addition amount of the hole transport agent to a value within the range of 70 to 90 parts by weight.

(3) Electron Transfer Agent (3) -1 Type As the type of electron transfer agent, it is preferable to include a quinone derivative. Examples thereof include naphthoquinone derivatives, diphenoquinone derivatives, azoquinone derivatives, and the like.
The reason for this is that by using a specific compound as an electron transporting agent, the electron accepting property is excellent, the electron transfer can be efficiently performed, and the compatibility with the charge generating agent is excellent. This is because an electrophotographic photoreceptor excellent in sensitivity characteristics can be provided.
Therefore, by using such a compound as a charge transfer agent (electron transfer agent) in an electrophotographic photoreceptor, an electrophotographic photoreceptor having excellent sensitivity characteristics can be provided, and thus a clear image can be obtained. It is possible to provide a static elimination-less type image forming apparatus.

(3) -2 Specific Example Further, specific examples of the electron transport agent include compounds (ETM-A to ETM-F) represented by the following formulas (14) to (19).

Moreover, it is also preferable to use a conventionally known electron transport agent alone or in combination. Examples of such electron transporting agents include diphenoquinone derivatives, benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7-tetranitro-9-fluorenone derivatives, dinitroanthracene derivatives, Dinitroacridine derivatives, nitroantharaquinone derivatives, dinitroanthraquinone derivatives, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride And various compounds having an electron accepting property such as dibromomaleic anhydride, and one kind or a mixture of two or more kinds may be used.
Of these electron transfer agents, compounds having an electron mobility of 1.0 × 10 ⁻⁸ cm ² / V · sec or more at an electric field strength of 5 × 10 ⁵ v / cm are more preferable.

(3) -3 Addition Amount In addition, in constituting the electrophotographic photosensitive member, the addition amount of the electron transport agent is set to a value within the range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin. preferable.
The reason for this is that when the added amount of the plurality of electron transfer agents is less than 10 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the plurality of electron transfer agents exceeds 100 parts by weight, the electron transfer agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.
Therefore, the addition amount of the electron transport agent is more preferably set to a value in the range of 20 to 80 parts by weight with respect to 100 parts by weight of the binder resin.

In addition, when determining the addition amount of an electron transport agent, it is preferable to consider the addition amount of a hole transport agent mentioned above. More specifically, the addition ratio (total ETM / total HTM) of the electron transport agent (total ETM) is a value within the range of 0.25 to 1.3 with respect to the hole transport agent (total HTM). It is preferable to do.
This is because if the ratio of all ETMs / all HTMs is outside this range, the sensitivity is lowered, which may cause practical problems.
Therefore, it is more preferable that the ratio of the total ETM / total HTM is set to a value within the range of 0.5 to 1.25.

(4) Charge generator (4) -1 type As the charge generator used in the electrophotographic photoreceptor of the present invention, metal-free phthalocyanine (τ type or x type), titanyl phthalocyanine (α type or Y type), It is preferable to include at least one compound selected from the group consisting of hydroxygallium phthalocyanine (type V) and chlorogallium phthalocyanine (type II).
The reason for this is to provide an electrophotographic photosensitive member that is more excellent in sensitivity characteristics, electrical characteristics, stability, etc. when a hole transporting agent and an electron transporting agent are used in combination by specifying the type of charge generating agent. It is because it can do.
Therefore, by using such a compound as a charge generating agent in an electrophotographic photoreceptor, an electrophotographic photoreceptor having excellent sensitivity characteristics, electrical characteristics, stability, and the like can be provided. It is possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

(4) -2 Specific Example Among these charge generating agents, it is more preferable to use phthalocyanine pigments (CGM-A to CGM-D) represented by the following formulas (20) to (23). preferable.

  It is also preferable to use a conventionally known charge generating agent. Such charge generators include phthalocyanine pigments such as oxo titanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo Organic photoconductors such as pigments, azulenium pigments, cyanine pigments, pyrylium pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, selenium, selenium-tellurium, selenium- One kind of inorganic photoconductive agent material such as arsenic, cadmium sulfide, and amorphous silicon, or a mixture of two or more kinds may be used.

(4) -3 Addition The addition amount of the charge generator is preferably set to a value within the range of 0.2 to 40 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the plurality of charge generating agents is less than 0.2 parts by weight, the effect of increasing the quantum yield becomes insufficient, and the sensitivity, electrical characteristics, stability, etc. of the electrophotographic photosensitive member are reduced. This is because it cannot be improved. On the other hand, when the added amount of the plurality of charge generating agents exceeds 40 parts by weight, the absorption coefficient for light having an absorption wavelength in the red and infrared or near infrared regions decreases, and the sensitivity of the photoreceptor, This is because electrical characteristics, stability, and the like may be reduced accordingly.
Therefore, it is more preferable that the amount of the charge generating agent is set to a value within the range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the binder resin.

Moreover, when using the compound (CGM-B) represented by Formula (21) among the charge generating agents used in the present invention, a dispersion aid represented by the following Formula (24) (for example, C.I. IPigment Orange 16) may be added.
This is because the charge generating agent (CGM-B) and the dispersion auxiliary agent (C. IPigment Orange 16) are used together to improve the dispersibility of CGM-B in the coating solution, and the coating solution pot This is because the life can be lengthened.

In addition, when using the dispersion | distribution adjuvant represented by Formula (24), it is preferable to make the addition amount into the value within the range of 30-200 weight part with respect to 100 weight part of all the electric charge generating agents.
This is because when the amount of the dispersion aid added is less than 30 parts by weight, the solubility in the solvent and the binder resin becomes insufficient, and an appropriate film as a photoreceptor cannot be produced. On the other hand, when the dispersion aid exceeds 200 parts by weight, the effect of increasing the quantum yield of the charge generating agent becomes insufficient, and the sensitivity characteristics, electrical characteristics, stability, etc. of the electrophotographic photoreceptor can be improved. It is because it becomes impossible.

(5) Binder Resin (5) -1 Type As the binder resin for dispersing the charge generator and the like, for example, polycarbonate resins such as bisphenol Z type, bisphenol ZC type, bisphenol C type, bisphenol A type, poly Arylate resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorine Polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide resin, polyurethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin Etc. One or a combination of two or more kinds of plastic resins, silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, other crosslinkable thermosetting resins, epoxy acrylate, urethane acrylate and other photo-curing resins It can be used.

(5) -2 Specific Example Among these binder resins, specifically, a binder resin (Resin-A) represented by the following formula (25) is more preferably used.

(6) Additive In addition to the above-mentioned components, the photoreceptor layer has various conventionally known additives such as an antioxidant, a radical scavenger, a singlet as long as it does not adversely affect the electrophotographic characteristics. Deterioration inhibitors such as quenchers and ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like can be blended. In order to improve the sensitivity of the photoreceptor layer, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

(7) Film thickness The thickness of the photoreceptor layer in the single-layer photoreceptor is usually a value in the range of 5 to 100 μm, preferably a value in the range of 10 to 50 μm.

(8) Conductive substrate As the conductive substrate on which such a photoreceptor layer is formed, various materials having conductivity can be used. For example, iron, aluminum, copper, tin, platinum, silver , Vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass and other metals, plastic materials on which these metals are deposited or laminated, and conductive fine particles such as carbon black are dispersed. Examples include plastics, glass coated with aluminum iodide, tin oxide, indium oxide, and the like.
Further, the shape of the conductive substrate may be any of a sheet shape, a drum shape, or the like in accordance with the structure of the image forming apparatus to be used. The substrate itself is conductive or the surface of the substrate is conductive. As long as it has. The conductive substrate preferably has sufficient mechanical strength when used.

(9) Solvent Various organic solvents can be used as a solvent for preparing the dispersion, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic carbonization such as n-hexane, octane and cyclohexane. Hydrogen: aromatic hydrocarbons such as benzene, toluene, xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane, dioxolane Ethers such as acetone, ketones such as methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylforma De, dimethyl sulfoxide and the like. These solvents are used alone or in combination of two or more.
Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge transport agent or the charge generator and the smoothness of the surface of the photoreceptor layer.

(10) Manufacturing method When the photoreceptor layer is formed by a coating method, a known method such as a roll mill, a ball mill, an attritor, an exemplary charge generator, charge transport agent, binder resin and the like, together with an appropriate solvent, What is necessary is just to disperse and mix using a paint shaker, an ultrasonic disperser, etc., and to prepare a dispersion liquid, apply | coat this by a well-known means, and to dry.

4). Other Conventionally known means can be used for the charger, the exposure device, the developing device, the transfer device, the cleaning device, and the like.
Further, it is preferable to include a process cartridge in which the electrophotographic photosensitive member is unitized. In other words, in addition to the electrophotographic photosensitive member, the process cartridge is formed by unitizing some of the constituent elements such as a charger, an exposure device, a developing device, a transfer device, and a cleaning device. Such a process cartridge can be handled easily and can be replaced easily and quickly including the electrophotographic photosensitive member when the sensitivity characteristics and the like of the electrophotographic photosensitive member deteriorate.

[Example 1]
(1) Preparation of electrophotographic photosensitive member 2.8 parts by weight of X-type metal-free phthalocyanine (CGM-A) represented by the formula (20) as a charge generator and a formula (3) 80 parts by weight of the amine stilbene derivative (HTM-A) represented by the formula (14), 35 parts by weight of the naphthoquinone derivative (ETM-A) represented by the formula (14) and the binder resin After containing 100 parts by weight of a polycarbonate resin (Resin-A) having a viscosity average molecular weight of 30,000 represented by the formula (25) and 800 parts by weight of tetrahydrofuran as a solvent, the mixture was ball milled for 1 hour. The mixture was mixed and dispersed to prepare a coating solution.
The obtained coating solution was applied to an aluminum base tube having a diameter of 30 mm and a length of 254 mm. Thereafter, it was dried with hot air at 130 ° C. for 30 minutes to obtain an electrophotographic photosensitive member having a single-layer type photosensitive layer having a thickness of 30 μm.

(2) Evaluation (2) -1 Image Evaluation The obtained electrophotographic photosensitive member was mounted on a multi-function printer Antico40 from which the charge eliminating lamp was removed. Subsequently, the original for memory image evaluation shown in FIG. 3 was continuously printed under the condition of A4 paper and 10,000 sheets, and image evaluation was performed according to the following criteria. The obtained results are shown in Table 1.
A: Generation of exposure memory in the gray area is not observed at all.
○: Almost no occurrence of exposure memory is visually observed in the gray area.
Δ: A little occurrence of exposure memory is visually observed in the gray portion.
X: Remarkable generation | occurrence | production of exposure memory is observed visually in a gray part.

(2) -2 Measurement of exposure memory potential After the obtained electrophotographic photosensitive member is mounted on a multifunction printer Antico40 (manufactured by Kyocera Mita Co., Ltd.) from which the charge eliminating lamp has been removed, it is charged so that the surface potential becomes 700V. The surface potential (V ₀₁ ) after the charging process at the time of non-exposure and the surface potential (V ₀₂ ) after the next charging process at the time of exposure are measured, and the difference is measured with the exposure memory potential (V ₀₁ −V ₀₂ ). did. The obtained results are shown in Table 1.

(2) -3 Crystallinity Evaluation The appearance of the obtained electrophotographic photoreceptor was visually observed, and the crystallinity was evaluated according to the following criteria. The obtained results are shown in Table 1.
(Double-circle): Crystallization is not seen at all.
○: Crystallization is hardly observed.
Δ: Slight crystallization is observed, but there is no problem in actual use.
X: Remarkable crystallization is observed.

[Examples 2 to 11]
Examples 2 to 11 are represented by the above-described formulas (4) to (13) instead of the amine stilbene (HTM-A) represented by the formula (3) as the hole transport agent used in Example 1. A single-layer photoreceptor was prepared and evaluated in the same manner as in Example 1 except that each of the compounds (HTM-B to K) was used.

[Comparative Examples 1-3]
In Comparative Examples 1 to 3, the hole transport agent used in Example 1 is represented by the following formulas (26) to (28) instead of the amine stilbene derivative (HTM-A) represented by the formula (3). An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the triphenylamine derivative (HTM-L to N) was used.

  As described above in detail, in the image forming apparatus of the present invention, by using an amine stilbene derivative having a specific structure as a hole transporting agent for an electrophotographic photosensitive member, the occurrence of exposure memory can be suppressed and extended over a long period of time. It has become possible to provide a static elimination-less type image forming apparatus capable of obtaining a clear image.

FIG. 2 is a diagram provided for explaining a static elimination-less type image forming apparatus. (A)-(c) is a figure provided in order to demonstrate the basic structure and deformation | transformation structure of a single layer type photoreceptor. It is a figure provided in order to demonstrate the document for image evaluation for measuring memory exposure amount.

Explanation of symbols

1: Electrophotographic photosensitive member 2: Charging unit 3: Exposure unit 4: Developing unit 5: Transfer unit 6: Cleaning unit 7: Image forming apparatus 10: Single layer type photoconductor 12: Conductive substrate 14: Photoconductor layer 16: Barrier layer 18: Protective layer 50: Memory image evaluation document 51: White portion 52: Black portion 53: Gray portion

Claims (7)

In a static elimination-less type image forming apparatus in which a charging unit, an exposure unit, a developing unit, and a transfer unit are arranged around a single layer type electrophotographic photosensitive member.
As the single-layer electrophotographic photosensitive member, a support layer is provided with a photosensitive layer made of at least a charge generating agent, a hole transporting agent, and a binder resin,
An image forming apparatus comprising an amine stilbene derivative represented by the following general formula (1) as the hole transport agent.

(In General Formula (1), A to D and R ^{1 to} R ¹⁴ are each an independent substituent, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and 1 carbon atom. A substituted or unsubstituted halogenated alkyl group having -20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted amino group, or , R ^{2 to} R ⁶ and any two of R ^{9 to} R ¹³ are carbocyclic structures formed by bonding or condensation, and the repeating numbers a to d are each independently 0 to 0. The integer of 4, m, and n are each independently an integer of 0-3.)   2. The image forming apparatus according to claim 1, wherein at least two of A, B, C, and D in the general formula (1) are substituted or unsubstituted aryl groups having 6 to 15 carbon atoms. . In the general formula (1), at least two of R ^{2 to} R ⁶ and / or at least two of R ^{9 to} R ¹³ are substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, 1 carbon atom The image forming apparatus according to claim 1, wherein the image forming apparatus is a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, or a bonded or condensed carbocyclic structure having 3 to 7 carbon atoms. R ² , R ⁶ , R ⁹ and R ^{13 in the} general formula (1) are substituted or unsubstituted alkyl groups having 1 to 6 carbon atoms, or substituted or unsubstituted alkoxy groups having 1 to 6 carbon atoms. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided.   The addition amount of the hole transport agent is set to a value within a range of 60 to 100 parts by weight with respect to 100 parts by weight of the binder resin. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the image forming apparatus is a cleaner-less type.   The image forming apparatus according to claim 1, wherein the electrophotographic photosensitive member is provided as a unitized process cartridge.

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