Mita Industrial Co., Ltd.

Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Keizo Kimoto

Kazunari Hamasaki

Yasufumi Mizuta

Masashi Tanaka

Mitsuji Tsujita

Hiroshi Takemoto

Hiroaki Iwasaki

Sakae Saito

Nobuyuki Kashiwagi

Tadashi Sakuma

Hirotsugu Nishikawa

Syoji Itsumi

Hiroki Morishita

Nariaki Tanaka

Yasuyuki Hanatani

Yoshiaki Kato

Ichiro Yamazato

Masato Katsukawa

Hiroaki Sakai

Tsuneo Oki

Tohru Ueno

Hiroshi Shiomi

Youichi Takesawa

Satoru Miura

Tomoki Tanaka

Mamoru Uemura

Mika Kawaguchi

A method of manufacturing a positively-charged single-layer electrophotographic photoreceptor including the steps of: producing a photosensitive layer application liquid containing a good solvent with respect to a binding resin and at least one organic solvent having a boiling point of 70&#xb0; C. or higher; and forming a photosensitive layer by coating a photosensitive layer support base having a wall thickness of 0.7 mm or less, with the photosensitive layer application liquid and then drying the photosensitive layer application liquid.

Method of manufacturing positively-charged single-layer electrophotographic photoreceptor, positively-charged single-layer electrophotographic photoreceptor, and image forming apparatus

Disclosed is a positively-charged single-layer electrophotographic photoreceptor in which a photosensitive layer containing at least a binding resin and a charge transporting material is provided on a photosensitive layer support base with a wall thickness of 0.7 mm or less, wherein when the charge transporting material is solely constituted by a hole transporting material, a content of the hole transporting material is 110 parts by mass or less with respect to 100 parts by mass of the binding resin, and when the charge transporting material is constituted by a hole transporting material and an electron transporting material, a content of the hole transporting material is 130 parts by mass or less and a content of the electron transporting material is 5 parts by mass or more with respect to 100 parts by mass of the binding resin.

Positively-charged single-layer electrophotographic photoreceptor and image forming apparatus

Disclosed is a positively-charged electrophotographic photoreceptor which uses a tubular photosensitive layer support base with a wall thickness of (t), wherein (t) is 0.7 mm or less, a chamfer angle (a) of an end surface of the photosensitive layer support base is 30&#xb0; or more and 60&#xb0; or less with respect to a longitudinal tangent of a surface of a tubular photosensitive layer support base, and an outer end surface-tail edge surface width (b) of the tubular photosensitive layer support base is 0.05 mm or more.

An electrophotographic method which uses a single-layer organic photosensitive material drum having a single organic photosensitive layer of a thickness of not smaller than 25 &mgr;m formed on an electrically conducting blank tube with a surface roughness Ra of not larger than 0.6 &mgr;m and rotates the photosensitive material drum at a peripheral speed of not smaller than 400 mm/sec, in order to execute an image-forming processing that includes electric charging, exposure to image-bearing light, developing, transfer, cleaning by a blade and removal of electric charge. Though the photosensitive material drum rotates at a high speed and a large frictional force is exerted on the cleaning blade, damage to the blade is effectively suppressed, and image is stably formed for extended periods of time without permitting the cleaning to become defective.

Electrophotographic method

An image-forming apparatus using a rubber blade having a rubber hardness of not smaller than 73.degree. for cleaning the residual toner on the photosensitive material drum, wherein a maximum rotational deviation r (mm) of said photosensitive material drum satisfies the following formula,

Image-forming apparatus including a photosensitive material drum and a

A photosensitive drum unit for an electrostatographic printing apparatus is disclosed. The drum unit includes a drum tube formed with at least one opening at one axial end thereof. A flange member is configured to be inserted into the opening in the drum tube. The flange member is provided with a support hole into which a shaft pin is inserted for supporting the drum tube and flange member. An earth plate is formed with projections or claws that extend radially outward from a peripheral edge of the earth plate such that the projections contact with an inner peripheral surface of the drum tube. The earth plate is also formed with a pair of contact pieces extend axially away from the earth plate and also extend toward one another. The contact pieces are spaced apart from one another by a predetermined distance but are also configured to contact and engage a portion of the shaft pin.

Drum unit and earth plate used in the drum unit

The electrophotographic process of this invention is characterized in that a single layer organic photosensitive material having an absorbance, at a maximum absorption wavelength of a visible portion per .mu.m of the thickness of a photosensitive layer, of at least 0.05 is used, and for its charge elimination, a light-emitting diode light which emits a light of a maximum absorption wavelength or a light in its vicinity is irradiated. According to this process, when image formation carried out repeatedly a number of times, a decrease in an early period surface potential can be effectively prevented and a brilliant image can be formed in a high concentration.

Electrophotographic method with residual charge elimination

A compact electrophotographic apparatus is attained by decreasing the diameter of the photosensitive drum so that a plurality of rotations of the drum are required to produce a single sheet image. Images of excellent quality, especially with respect to the lack of stepwise density decrease across the image due to multiple drum rotations per image, are achieved by providing for discharge of the photosensitive drum so that the residual potential on the drum is 10% or less of the charged surface potential after discharge on the first rotation of the drum and the increase in the residual potential is not more than 30% after discharge on the last rotation of a sheet making cycle.

Electrophotographic apparatus with photosensitive drum requiring

The present invention provides a process for packing a drum-shaped electrophotographic photoreceptor comprising the steps of folding a wrapping-start edge portion of a light-shielding packing sheet outwardly in a diametrical direction of the photoreceptor across a width of the packing sheet, and wrapping the packing sheet on a circumferential surface of the photoreceptor. The packing process of the present invention enables an electrophotographic photoreceptor, which has a small diameter, or has a soft surface and is susceptible to scratching, to be packed without forming scratches on its surface and decreasing its photosensitivity.

Process for packing electrophotographic photoreceptor

Disclosed is a laminate type photosensitive material for the electrophotography, which comprises a charge-generating layer and a charge-transporting layer, which are formed on an electroconductive substrate, wherein the charge-transporting layer comprises a first charge-transporting material having an ionization potential smaller than that of a charge-generating material used for the charge-generating layer and a second charge-transporting material having an ionization potential larger than that of the charge-generating material. In this photosensitive material, by using a charge-transporting material having an ionization potential larger than that of the charge-generating material in combination with the charge-transporting material having an ionization potential smaller than that of the charge-generating material, a good residual potential can be maintained without disturbing injection of holes in the charge-transporting layer, the stability of the surface potential at the repeated use is improved and a good charging capacity can be attained.

Laminate type photosensitive material for electrophotography

The electrophotosensitive material in accordance with the present invention containing a layer which contains polycarbonate as a binding resin and of which glass transition temperature is not lower than 62.degree. C. This layer is excellent in adhesion to the foundation. This layer may be a photosensitive layer containing a m-phenylenediamine compound as a charge transferring material, or a photosensitive layer containing a m-phenylenediamine compound and a perylene compound as a charge generating material. The present invention also provides a photosensitive layer of which the amount of residual tetrahydrofuran is adjusted to a predetermined value or less, thereby to prevent the photosensitive layer from being decreased in sensitivity due to ultraviolet rays or visible ray.

Electrophotosensitive material and method of manufacturing the same

Disclosed is an organic laminated photosensitive material of the positive charging type comprising an electroconductive substrate, a charge-transporting layer formed on the substrate and a charge-generating and transporting layer formed on the charge-transporting layer. The charge-transporting layer is composed of a binder resin containing a hole-transporting substance, and the charge-generating and transporting layer is composed of a binder resin containing a hole-transporting substance different from the hole-transporting substance in the charge-transporting layer and a charge-generating substance. The oxidation potential of the hole-transporting substance in the charge-generating and transporting layer is higher than that of the hole-transporting substance in the charge-transporting layer, but the difference of the oxidation potential between the hole-transporting substances of the two layers is smaller than 0.3 eV. In this photosensitive material, injection of holes between the two layers can be easily performed, and the sensitivity can be highly improved.

Organic laminated photosensitive material of positive charging type and

Disclosed is an organic laminated photosensitive material of the positive charging type comprising an electroconductive substrate, a charge-transporting layer formed on the substrate and a charge-generating and transporting layer formed on the charge-transporting layer. The charge-transporting layer is composed of a binder resin containing a hole-transporting substance, and the charge-generating and transporting layer is composed of a binder resin containing a charge-generating substance and a hole-transporting substance. In this laminated photosensitive material, an excellent sensitiveity is maintained even if the topmost charge-generating layer has a large thickness, and therefore, a high surface saturation charge voltage and an excellent printing resistance can be maintained in addition to an increased sensitivity.

Growing community of inventors

Osaka, Japan

Keizo Kimoto