Mita Industrial Co., Ltd.

Toru Nakazawa

Akira Fushida

Yasushi Kamezaki

Keisuke Sumida

Mikio Kakui

Nariaki Muto

Tatsuo Aizawa

Yoshiaki Kato

Hideo Fukuda

Tatsuo Maeda

Keiichi Nagahashi

Hideyuki Sasaki

Yasuharu Utsunomiya

Nobuhiko Kozuka

Masahiko Maeda

Ryuji Wataki

Masahiro Tsutsumi

Toshihiko Nishiguchi

Hirotsugu Nishikawa

Katsuya Kitaura

Kazuo Matsumoto

Disclosed is a chucking device for chucking a drum to keep it vertical while the drum is immersed in a coating liquid to be coated with the coating liquid. The chucking device comprises upper and lower pressure members having tapered peripheral surfaces at their ends facing each other. An annular elastic member is fitted between the tapered peripheral surfaces. The pressure members are constantly urged toward each other. When chucking a drum, the lower pressure member is moved away from the upper pressure member by means of compressed air so as to contract the elastic member, thereby allowing the pressure members and the elastic member to be inserted into the drum. Then, the compressed air is released, allowing the pressure members to contact each other. This causes the elastic member to be pressed outward by the tapered peripheral surfaces to tightly contact the inner surface of the drum. Then, the drum is moved upward together with the elastic member until it abuts against a positioning portion of the upper pressure member.

Drum chucking device

This invention provides an electrophotosensitive material comprising a conductive substrate and a photosensitive layer formed thereon, the photosensitive layer includes a perylene compound (I) and an X-type metal-free phtalocyanine as a charge-generating ingredient and a diamine derivative (II) as a charge-transferring ingredient in the binding resin. This electrophotosensitive material is especially superior in sensitivity and reproductivity. Formulas (I) and (II) are defined as follows: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 l, m, n, o and p have the same meanings as defined in the text of the specification.

Electrophotosensitive material with x-type metal free phthalocyanine and

The present invention provides an electrophotosensitive material comprising a conductive substrate, and a photosensitive layer provided on the conductive substrate and containing a m-phenylenediamine compound represented by the general formula [I]: ##STR1## (wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R are the same as defined before). The present electrophotosensitive material has high sensitivity and is easy to be manufactured.

Perylene electrophotosensitive material with m-phenylenediamine

The present invention provides an electrophotosensitive material containing the diamine derivative represented by the following general formula (I) and at least one selected from the group consisting of the hydrazone compound, fluorene compound and m-phenylenediamine compound. ##STR1## wherein R.sup.5 to R.sup.9, l, m, n, o and p are as defined.

Electrophotosensitive material with combination of charge transfer

An electrophotographic process includes performing removal of electricity or pre-charging by direct current corona discharge and main charging by direct current corona discharge of a polarity reverse to the polarity for removal of electric charge or pre-charging on an organic photoconductive photosensitive layer chargeable at both the positive and negative polarities. Then is performed imagewise exposure, development with a toner and transfer of the toner image. Such operations are repeated to form plural images. Main charging is carried out with an applied current such that the photosensitive layer surface potential is saturated at 500 to 700 volts (absolute value) and removal of electric charge or pre-charging is carried out with at an applied current lower than the saturation injected current value and corresponding to 40 to 90% thereof.

Electrophotographic process including controlling applied current values

A toner cleaning apparatus for removing a toner left on the surface of an electrophotographic photosensitive material by a doctor blade in the electrophotographic process includes an elastic doctor blade having a toner-scraping top end, a holder for supporting the base of the doctor blade, a fulcrum for swingably supporting the holder and a pressing mechanism for pressing the top end of the doctor blade to the surface of the photosensitive material, wherein the fulcrum and doctor blade are arranged so that on the feed-out side of the photosensitive material, the contact angle .alpha. between the top end of the doctor blade and the photosensitive material is smaller than the angle .beta. between the photosensitive material and the line connecting the top end of the doctor blade to the fulcrum, and the pressing mechanism and doctor blade are arranged in such an elastic engagement relation that as the applied stress is increases, the top end of the doctor blade is retreated to the feed-out side and the degree of flexion of the doctor blade is increased.

Toner cleaning apparatus in electrophotography

In the electrophotographic process in which an image is formed by performing imagewise light exposure, toner development, toner image transfer and cleaning after charging a photoconductive photosensitive layer by direct current corona discharge, an organic photoconductive photosensitive layer in which the surface potential is saturated at 500 to 700 volts as the absolute value is used as the photosensitive layer and charging is carried out at an injection current which becomes saturated at said surface potential. According to this process, good images can be stably obtained irrespectively of environmental changes or even if the cycle number of the copying operation is increased.

Electrophotographic process

An electrophotographic process includes performing main charging by direct current corona discharge and imagewise exposure on an organic photoconductive photosensitive layer chargeable at both positive and negative polarities, developing a formed electrostatic image with a magnetic brush of a toner, bringing the photosensitive layer bearing a toner image thus formed thereon into contact with a copying sheet, performing transfer of the toner by direct current corona discharge of the same polarity as that of the main charging step applied to the back surface of the copying sheet, and cleaning the photosensitive layer, from which the toner has been transferred, with the magnetic brush after removal of residual charge. The injected current of the direct current corona discharge during the transfer of the toner is set at a level 23 to 35 times the injected current initiating the transfer of the toner. After the transfer of the toner, the photosensitive layer is subjected to direct current corona discharge of a polarity reverse to the polarity of the direct current corona discharge for main charging to charge the residual at a uniform polarity.

Process for the prevention of the memory effect in an organic

A photosensitive composition for electrophotography comprising polyvinyl carbazole, a charge-generating organic pigment, and as a sensitizing agent a silicone oil, thereby enhancing the sensitivity of the resulting photosensitive layer and improving the aging characteristic thereof.

Photosensitive composition for electrophotography having polyvinyl

Disclosed is a photosensitive material for the electrophotography, which comprises a dispersion of a charge-generating pigment in a charge-transporting medium composed mainly of a polyvinyl carbazole resin, wherein a perylene pigment represented by the following general formula: ##STR1## wherein R.sub.1 and R.sub.2 stand for a hydrogen atom or a substituted or unsubstituted alkyl or aryl group, is dispersed and incorporated as the charge-generating pigment in an amount of 1 to 40 parts by weight per 100 parts by weight of the polyvinyl carbazole resin and a halogeno-p-benzoquinone is further incorporated in an amount of 1 to 60 parts by weight per 100 parts by weight of the polyvinyl carbazole resin.

Photosensitive material for electrophotography contains

Disclosed is an organic photosensitive material for electrophotography comprising a charge-transporting medium composed mainly of polyvinyl carbazole and a perylene type pigment as a charge-generating pigment dispersed in said charge-transporting medium, wherein 1 to 30 parts by weight of a halo-naphthoquinone and 1 to 100 parts by weight of phenanthrene or pyrene are incorporated per 100 parts by weight of the polyvinyl carbazole. This photosensitive material is excellent in the sensitivity and the resistance to the repeated light exposure.

Organic photosensitive material for electrophotography comprising

Disclosed is a photosensitive plate for electrophotography, which comprises a conductive substrate and a layer of a composition formed by dispersing a photoconductor in a binder resin, which is formed on the substrate, wherein the resin binder comprises an epoxy resin component and an amine type curing agent component and the resin binder further comprises an acid anhydride as the ozone deterioration preventing agent. This photosensitive plate is excellent in the ozone resistance and the moisture resistance.

Electrophotographic CdS or CdSSe with ozone deterioration inhibitor

Disclosed is an electrophotographic photosensitive composition which comprises a phthalocyanine type photoconductor dispersed in an electrically insulating resin medium, wherein a nitrophthalic anhydride represented by the following formula: ##STR1## wherein n is a number of 1 or 2, is incorporated as a sensitizer.

Sensitized electrophotographic photosensitive composition

Disclosed is a photosensitive material for electrophotography comprising a conductive substrate and a layer of a composition comprising a dispersion of a photoconductive pigment in a binder resin, which is formed on the conductive substrate, wherein a (dialkypyrophosphato) organic titanate is incorporated into said composition. This photosensitive material is excellent in the ozone resistance and the moisture resistance.

Cadmium photoconductor with (dialkylpyrophosphato) organic titanate

Disclosed is a photosensitive composition for electrophotography, which comprises a dispersion of a disazo-type photoconductor in an electrically insulating resin medium, wherein a nitrophthalic anhydride represented by the following formula: ##STR1## wherein n is a number of 1 or 2, is incorporated as a sensitizer.

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Osaka, Japan

Toru Nakazawa