The present invention provides a single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer formed on the conductive substrate, wherein the photosensitive layer contains a phthalocyanine compound as an electric charge generating material, a hole transferring material and an electron transferring material in a binder resin, and that a difference in absolute value between a plus polarity sensitivity and a minus polarity sensitivity measured under the conditions of an exposure wavelength of 780 nm and an exposure energy of 1.0 μJ/cm2 is not more than 500 312 V, and a reversal development type digital image forming apparatus using the electrophotosensitive material, which does not include a charge neutralizing step.

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Patent
   RE42189
Priority
Oct 25 1999
Filed
Sep 15 2009
Issued
Mar 01 2011
Expiry
Jun 20 2020
Inventors
Tanaka, Yu…
Assg.orig
Kyocera Mi…
Assg.curr
Kyocera Mi…
Entity
Large
Referenced by
1
References
39
Maint.:
all paid
9. A method of producing a single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer formed on the conductive substrate, the photosensitive layer containing a phthalocyanine compound as an electric charge generating material, a hole transferring material and an electron transferring material in a binder resin, characterized in that the photosensitive layer is formed by selecting the phthalocyanine compound, hole transferring material, electron transferring material and binder resin so that a difference in absolute value between a plus polarity sensitivity and a minus polarity sensitivity is not more than 500 312 V under the measuring conditions of an exposure wavelength of 780 nm and an exposure energy of 1.0 μJ/cm2.
1. A single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer formed on the conductive substrate, characterized in that the photosensitive layer contains a phthalocyanine compound as an electric charge generating material, a hole transferring material and an electron transferring material in a binder resin, and that a difference in absolute value between a plus polarity sensitivity and a minus polarity sensitivity measured under the conditions of an exposure wavelength of 780 nm and an exposure energy of 1.0 μJ/cm2 is not more than 500 V 312 V, wherein the single-layer type electrophotosensitive material is used in a method including charging the electrophotosensitive material, exposing an image to form a static latent image, developing the static image to form a toner image, and transferring the toner image along a forward direction of the electrophotosensitive material, the method not including a charge neutralizing step.
2. The single-layer type electrophotosensitive material according to claim 1, wherein the absolute value of the plus polarity sensitivity is smaller than that of the minus polarity sensitivity.
3. The single-layer type electrophotosensitive material according to claim 2, which contains, as the hole transferring material, a compound represented by the general formula (1): ##STR00009##
wherein R1 and R3 are the same or different and each represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl or alkoxy group which may have a substituent; and R2 and R4 are the same or different and each represents a hydrogen atom, or an alkyl or alkoxy group which may have a substituent, provided that R2 and R4 are hydrogen atoms when R2 and R4 are substituted at the para-position.
4. The single-layer type electrophotosensitive material according to claim 2, which contains, as the electron transferring material, at least one selected from the group of compounds represented by the general formula (2): ##STR00010##
wherein R5 represents a halogen atom, or an alkyl or aryl group which may have a substituent; and R6 represents an alkyl or alkoxy group which may have a substituent, or a group: —O—R6a, which represents an alkyl or aryl group which may have a substituent;
the general formula (3): ##STR00011##
wherein R7 and R8 are the same or different and each represents an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, or a nitro group; and n represents an integer of 0 to 3;
the general formula (4): ##STR00012##
wherein R9a, R9b, R9c and R9d are the same or different and each represents a hydrogen atom, or an alkyl or aryl group which may have a substituent; and
the general formula (5): ##STR00013##
wherein R10 and R11 are the same or different and each represents an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, or nitro group; and n represents an integer of 0 to 3.
5. The single-layer type electrophotosensitive material according to claim 2, which contains, as the hole transferring material, a compound represented by the general formula (1) and, as the electron transferring material, a compound represented by the general formula (2).
6. The single-layer type electrophotosensitive material according to claim 2, wherein the content of the phthalocyanine compound is from 0.1 to 4.0% by weight based on the weight of the binder resin.
7. The single-layer type electrophotosensitive material according to claim 2, which contains, as the binder resin, a bisphenol Z type polycarbonate resin having a weight-average molecular weight of 15,000 to 100,000.
8. The single-layer type electrophotosensitive material according to claim 2, wherein the film thickness of the photosensitive layer is from 10 to 35 μm.
10. The method of producing a single-layer type electrophotosensitive material according to claim 9, wherein said electron transferring material is at least one member selected from the group consisting of a compound of formula (2): ##STR00014##
wherein R5 represents a halogen atom, or an alkyl or aryl group which may have a substituent; and R6 represents an alkyl or alkoxy group which may have a substituent, or a group: —O—R6a, which represents an alkyl or aryl group which may have a substituent;
the formula (3): ##STR00015##
wherein R7 and R8 are the same or different and each represents an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, or a nitro group; and n represents an integer of 0 to 3;
the formula (4): ##STR00016##
wherein R9a, R9b, R9c and R9d are the same or different and each represents a hydrogen atom,
or an alkyl or aryl group which may have a substituent; and the formula (5): ##STR00017##
wherein R10 and R11 are the same or different and each represents an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, or nitro group; and n represents an integer of 0 to 3.
11. A method for reversal development in a digital image forming apparatus comprising charging the apparatus with the single-layer type electrophotosensitive material of claim 1, carrying out an exposure of exposing an image to form a static latent image, developing said static latent image to form a toner image, and transferring said toner image along a forward direction of the electrophotosensitive material, wherein a voltage is applied in the transferring which has a polarity reverse to a voltage to be applied in the charging, further wherein the method does not include a charge neutralizing step.

100 msec 50 msec.) was irradiated (exposure energy: 1.0 μJ/cm2) with monochromic light having a wavelength of 780 nm (half-width: 20 nm, light intensity: 20 μW/cm2) from white light of a halogen lamp as an exposure light source through a band-pass filter, and then a surface potential at the time at which 500 msec. have passed since the beginning of exposure was measured as a potential after exposure VLP (V). The smaller the potential after exposure, the higher the sensitivity of the photosensitive material.

[Evaluation of minus polarity sensitivity]

In the same manner as in case of the <evaluation of plus polarity sensitivity>, except that a voltage was applied to the electrophotosensitive materials of the respective Examples and Comparative Examples to charge the surface at −800 V using a drum sensitivity tester (manufactured by GENTEC Co. under the trade name of GENTEC SINCIA 30 M)), a surface potential at the time at which 500 msec. have passed since the beginning of exposure was measured as a potential after exposure VLN (V)

<Evaluation of transfer memory potential>

After the electrophotosensitive materials of the respective Examples and Comparative Examples were installed in a multifunction printer Antico 40 excluding a charge neutralizing lamp, manufactured by KYOCERA-MITA Co., Ltd., a surface potential on application of no transfer bias and a surface potential on application of a transfer bias after the following charge step were measured and a difference between them was taken as a transfer memory potential. The case where the transfer memory potential is 45 V or less at which no transfer memory image is generated was rated “Pass”, whereas, the case where the transfer memory potential is 45 V or more was rated “Fail”.

<Evaluation of exposure memory potential>

After the electrophotosensitive materials of the respective Examples and Comparative Examples were installed in a multifunction printer Antico 40 excluding a charge neutralizing lamp, manufactured by KYOCERA-MITA Co., Ltd., a surface potential on no exposure and a surface potential on exposure after the following charge step were measured and a difference between them was taken as an exposure memory potential. Similar to the case of the transfer memory potential, the case where the exposure memory potential is 45 V or less at which no transfer memory image is generated was rated “Pass”, whereas, the case where the exposure memory potential is 45 V or more was rated “Fail”.

<Evaluation of transfer memory image>

After the electrophotosensitive materials of the respective Examples and Comparative Examples were installed in a multifunction printer Antico 40 excluding a charge neutralizing lamp, manufactured by KYOCERA-MITA Co., Ltd., a printing test was carried out and it was visually judged whether a transfer memory image is generated or not. As shown in FIG. 2, the transfer memory image refers to an image wherein a black lateral band was generated in a drum longitudinal direction by a reduction in surface potential of the photosensitive material at the portion to which the transfer bias was applied in case where the printing test was carried out using an original having a gray front surface (Munsell value: N=6.5).

<Evaluation of exposure memory image>

After the electrophotosensitive materials of the respective Examples and Comparative Examples were installed in a multifunction printer Antico 40 excluding a charge neutralizing lamp, manufactured by KYOCERA-MITA Co., Ltd., a printing test was carried out and it was visually judged whether an exposure memory image is generated or not. The exposure memory image refers to an image wherein a ghost image of the exposed portion was generated at the gray portion by a reduction in surface potential of the photosensitive material at the strongly exposed portion (black solid portion) in case where the printing test was carried out using an original as shown in FIG. 3.

TABLE 1
Plus Minus Difference in Transfer Exposure Exposure
polarity polarity absolute value memory memory memory
Kind of sensitivity sensitivity of sensitivity potential potential Transfer potential
ETM (V) (V) (V) (V) (V) memory image (V)
Example 1 ET-1 132 150 18 15 10 No memory image No memory image
was generated was generated
Example 2 ET-2 141 290 149 20 26 No memory image No memory image
was generated was generated
Example 3 ET-3 144 341 197 30 32 No memory image No memory image
was generated was generated
Example 4 ET-4 150 352 202 26 10 No memory image No memory image
was generated was generated
Example 5 ET-5 131 153 22 15 25 No memory image No memory image
was generated was generated
Example 6 ET-6 205 322 117 35 32 No memory image No memory image
was generated was generated
Example 7 ET-7 252 550 298 35 36 No memory image No memory image
was generated was generated
Example 8 ET-8 223 704 481 25 44 No memory image No memory image
was generated was generated
Comp. ET-9 131 652 521 55 66 Lateral black Ghost image was
Example 1 band was generated
generated
Comp. ET-10 123 663 540 70 76 Lateral black Ghost image was
Example 2 band was generated
generated
Comp. ET-11 130 661 531 85 90 Lateral black Ghost image was
Example 3 band was generated
generated

TABLE 2
Plus Minus Difference in Transfer Exposure Exposure
polarity polarity absolute value memory memory memory
Kind of sensitivity sensitivity of sensitivity potential potential Transfer potential
ETM (V) (V) (V) (V) (V) memory image (V)
Example 9 ET-1 109 128 19 13 4 No memory image No memory image
was generated was generated
Example 10 ET-2 112 250 138 18 24 No memory image No memory image
was generated was generated
Example 11 ET-3 109 312 203 24 29 No memory image No memory image
was generated was generated
Example 12 ET-4 115 320 205 22 5 No memory image No memory image
was generated was generated
Example 13 ET-5 108 322 14 13 25 No memory image No memory image
122 was generated was generated
Example 14 ET-6 173 290 117 32 30 No memory image No memory image
was generated was generated
Example 15 ET-7 211 523 312 33 30 No memory image No memory image
was generated was generated
Example 16 ET-8 189 675 486 20 42 No memory image No memory image
was generated was generated
Comp. ET-9 100 623 523 56 60 Lateral black Ghost image was
Example 4 band was generated
generated
Comp. ET-10 95 630 535 68 70 Lateral black Ghost image was
Example 5 band was generated
generated
Comp. ET-11 103 620 517 90 86 Lateral black Ghost image was
Example 6 band was generated
generated

As is apparent from Table 1, Table 2 and FIG. 1, when a difference in absolute value between a plus polarity sensitivity and a minus polarity sensitivity is 500 V or less, both of a transfer memory potential and an exposure memory potential becomes 45 V or less so that no memory image is generated.

The disclosure of Japanese Patent Application Serial No. 11-302914, filed on Oct. 25, 1999, is incorporated herein by reference.

INVENTORS:

Tanaka, Yuji, Hayashi, Masakatsu, Iwasaki, Hiroaki, Imanaka, Yukikatsu

THIS PATENT IS REFERENCED BY THESE PATENTS:
Patent Priority Assignee Title
10656543, May 25 2016 Kyocera Document Solutions Inc Electrophotographic photosensitive member, process cartridge, and image forming apparatus
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