Sharp Kabushiki Kaisha Corporation

Yoshihide Shimoda

Satoshi Katayama

Kazushige Morita

Tatsuhiro Morita

Hiroko Ishibashi

Shuhei Tsuchimoto

Hiroshi Sugimura

Masayuki Sakamoto

Makoto Kurokawa

Eiji Imada

Sayaka Fujita

Yuriko Shindoh

Tadashi Nakamura

Masanori Matsumoto

Mikio Kakui

Tomoko Kanazawa

Rikiya Matsuo

Koichi Toriyama

Yoshimi Kojima

Akihiko Kawahara

Yoichi Takesawa

A multiple number of image forming stations are provided for multiple development colors including black. Each station having a photoreceptor. Each one of the photoreceptors has a charge transport layer including a binder resin that is a blend of at least two kinds of resins. The blended ration of at least two kinds of binder resins for the photoreceptor for black is made different from that of the binder resins for the photoreceptors for the other development colors. The photoreceptor for black presents a greater abrasion resistance than the photoreceptors for the other development colors. This structure makes it possible to use all the photoreceptors for back and colors, for and within, a concurrent period.

Color image forming apparatus

An electrophotographic photoreceptor, in which the increase of VL is controlled below 15 V by controlling the content ratio M (ppm) of a charge transporting material CTMto a charge transporting material CTMwithin a specific range, wherein the ionization potential Ip(2) of the CTMis smaller than the ionization potential Ip(1) of the CTMin the constituent of the photosensitive layer, and thereby the electrophotographic photoreceptor has only a little reduction of image concentration. A method for producing an electrophotographic photoreceptor having &#x394;VL which is controlled below 15 V, wherein, in a case where the ionization potential of the charge transporting material used in the previous run of production is small, &#x394;VL can be set below 15 V by using, in the next production, a dip coating liquid, which comprises, as a constitutive material, a charge transporting material in which the difference between the ionization potential of the current material and that of the previous material is set below 0.25 eV.

Electrophotographic photoreceptor and production method thereof

An electrophotographic color image forming apparatus including a multiple number of photoreceptors for multiple development colors including black, is constructed such that the photoreceptors satisfy the following relation:0.5&#x3c;()&#x3c;0.8,where X represents the reduction in film thickness (&#x212b;) per 1&#xd7;10mm of the traveling distance of the photoreceptor for black development and Y represents the reduction in film thickness (&#x212b;) per 1&#xd7;10mm of the traveling distance of the photoreceptors for the other development colors. This limitation is aimed at differentiating the abrasion resistance of the photoreceptors between that for black and that for colors and designating the reduced amounts of the film thickness per unit traveling distance to fall within the predetermined ranges, whereby it is possible to prevent the drum for black development, which is used most frequently, alone, from being worn away at an earlier time. Accordingly, both the drums for black and for colors can be replaced at approximately the same time, to the maintenance cost can be reduced.

It is an object of the invention to inspect defects of a film formed on a relatively rough surface of a substrate by the light interference method. A substrate on which a film is formed is irradiated with light of a longer wavelength than the surface roughness Rmax or Rz of the substrate to obtain interference fringes to inspect defects of the film formed on the substrate. Especially, it is preferable that when the surface roughness Rmax or Rz is 0.5 &mgr;m or more, the substrate is irradiated with light of a wavelength beyond a little longer wavelength than the surface roughness Rmax or Rz. The surface of the substrate is subjected to a cutting process. Specifically, it is possible to inspect defects of the electric charge generation layer, electric charge transport layer, or undercoat layer of an electrophotographic photoreceptor. This photoreceptor is mounted in a digital copier or printer. Further, monochromatic light is preferably applied. Alternatively, indirect light of the light reflected from a reflector plate or the light diffused by a diffusing plate is preferably applied.

Film defect inspection method for a film formed on a substrate

Test method and control method for coating liquid for electrophotographic photoconductor

An electrophotographic photosensitive element is provided with a photosensitive layer containing a charge generating substance and a charge transport substance on a conductive support. X-type metal-free phthalocyanine and a disazo compound are contained as a charge generating substance. With the photosensitive element, sufficient sensitivity is achieved so as to cause virtually no problem, and it is possible to reduce possibility of causing an instable electrostatic property such as a reduction in a charge potential and an increase in a remained potential, even in the case of frequent reuse.

Electrophotographic photosensitive element and manufacturing method thereof

Highly sensitive and highly durable electrophotographic photoreceptors which generate faultless images can be produced by forming the under-coating layer on the conductive support and forming the photoreceptive layer on the layer. The under-coating layer contains dendritic titanium oxide. The under-coating layer contains the dendritic titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide, of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s), and an alcohol soluble polyamide resin.

Electrophotographic photoreceptor, process for production thereof, and

An electrophotographic photoconductor comprising a conductive support, an undercoating layer formed on the conductive support, and a photosensitive layer laminated on the undercoating layer, wherein the undercoating layer comprises non-conductive titanium oxide particles and a polyamide resin, the non-conductive titanium oxide particles being 80 to 99 wt % of the undercoating layer, and the undercoating layer has a thickness of 0.5 to 4.8 .mu.m.

Electrophotographic photoconductor and a method for manufacturing the

1,2,4,5-Benzoylenebis(naphto[1,8-de]pyrimidine) compounds of the followig formula (I) or (II): ##STR1## wherein R and R' are, the same or different, hydrogen atom, a halogen atom, hydroxyl group, nitro group, cyano group, an alkyl group which may be substituted, an alkoxyl group which may be substituted, an aryl group which may be substituted, an aralkyl group which may be substituted, a carboxyl group which may be esterified or a carbamoyl group which may be substituted and m and n each are an integer from 1 to 6, and photosensitive members for electrophotography having a photosensitive layer containing them.

1,2,4,5-benzoylenebis(naphtho[1,8-de]pyrimidine) compounds and their use

An apparatus for the production of photoconductive components for use in electrophotography, including a coating tank that contains a certain amount of coating, the tank having a coating-supply opening, at a lower portion through which the coating is supplied to the tank, and a partition that is positioned between the inner wall of the tank and the outer wall of the electric conductor, whereby when an electric conductor to be coated is immersed in the coating and removed from the coating, occurrence of a turbulent flow of the coating in the vicinity of the electric conductor can be prevented.

Apparatus for the production of photoconductive components for use in

1,2,4,5-Benzoylenebis(anthraquinone[1,2-d]imidazole) compounds represented by following general formula (1) or (2) ##STR1## wherein R and R' each are hydrogen atom, a halogen atom, hydroxyl group, a lower alkyl group, a lower alkoxy group or an aryl group which may be substituted and m and n each are an integer of 1 or 2, and photosensitive members for electrophotography having a photosensitive layer containing them.

1,2,4,5-benzoylenebis(anthraquinone[1,2-d]imidazole) compounds and

1,2,4,5-benzoylenebis(anthraquinone[1,2-d]imidazole) compounds represented by following general formula (1) or ##STR1## wherein R and R' each are hydrogen atom, a halogen atom, hydroxyl group, a lower alkyl group, a lower alkoxy group or an aryl group which may be substituted and m and n each are an integer of 1 or 2, and photosensitive members for electrophotography having a photosensitive layer containing them.

Growing community of inventors

Nara, Japan

Yoshihide Shimoda