Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic image; a developing device for developing the electrostatic image on the image bearing member with toner into a toner image; a transfer device for transferring the toner image onto a transfer material; a charging and cleaning device for removing residual toner after image transfer from the image bearing member and for charging the image bearing member; wherein the charging and cleaning device includes a rotatable member which has an electroconductive foam for retaining electroconductive particles and which is rotatable while rubbing the image bearing member.

Abstract: An electrophotographic process is implemented with improved ghost memory and with high chargeability even under circumstances of increased process speed or compactified structure and the electrophotographic process forms an image on a photosensitive member having a photosensitive layer through a series of steps including steps of charge elimination, charging, latent image exposure, and development to form a toner image, wherein light used in the latent image exposure step is light of a wavelength within such a range that a value of (optical memory before charging)/(sensitivity) of the photosensitive layer is not more than 1.5 times a minimum value. The optical memory before charging means lowering in chargeability due to light irradiation before charging.

Abstract: An image forming apparatus which largely improves the reliability of electrophotographic apparatuses and can accommodate their extremely large productivity comprises an image forming part which forms toner images on an image carrying member, an image transfer part which transfers the toner images on the image carrying member onto a transfer material, and a cleaning part which removes post-transfer residual toner left on the image carrying member after the images are transferred onto the transfer material by the image transfer part, wherein the image carrying member is an amorphous silicon photosensitive member and an initial average gradient &Dgr;a of the photosensitive member is 0.0001 to 0.005.

Abstract: An electrophotographic amorphous silicon photosensitive member is used for an electrophotographic apparatus that forms images by the electrophotographic method, and an image forming apparatus uses this photosensitive member, which includes a drum-shaped cylindrical conductive substrate, and a photosensitive layer that contains amorphous silicon, thus structuring an electrophotographic photosensitive drum. Then, the outer diameter of this photosensitive drum is configured to be gradually smaller from the vicinity of the central portion thereof in the generatrix direction to both ends in the longitudinal direction, hence making it possible to enhance the cleaning effect on residual toner.

Abstract: A photosensitive member to be used for an image-forming apparatus effectively suppresses the effect of wetting the foreign matters adhered to the surface thereof, reduces the load of the cleaning unit and prolong the service life of the photosensitive member so that the image-forming apparatus may be down-sized. In the photosensitive member, the surface free energy (&ggr;) on the uppermost surface of the photosensitive member is made between 35 and 65 mN/m and the variation of the surface free energy &Dgr;&ggr; is made less than 25 mN/m during long operation.

Abstract: The present invention relates to an electrophotographic apparatus in which maximum potential difference &Dgr;VD (volt) in a potential of a dark portion of the electrostatic image in the longitudinal direction, maximum potential difference &Dgr;VL in a potential of a light portion of the electrostatic image in the longitudinal direction, a value a (1/volt) represented by (variation amount in density, in the longitudinal direction, in the image formed by developing the light portion with the developing means)/(the maximum potential difference &Dgr;VD) and a value b (1/volt) represented by (variation amount in density, in the longitudinal direction, in the image formed by developing the light portion with the developing means)/(the maximum potential difference &Dgr;VL) satisfy a relation: 0.3≦a×&Dgr;VD+b×&Dgr;VL≦0.3 in which 100≧|&Dgr;VD|≧20 and 100≧|&Dgr;VL|≧20.

Abstract: In order to reduce the cost of a photosensitive member and to prevent the fluctuation in image density and the image smear by highly precise temperature control, the image forming apparatus of the present invention includes: a cylindrical photosensitive member with a conductive substrate having a thickness not smaller than 0.1 mm and smaller than 2.5 mm, and a light-receiving layer having a photoconductive layer on the conductive substrate, the light-receiving layer containing at least amorphous silicon; and a charging device for charging the photosensitive member, wherein the photoconductive layer has a thickness not smaller than 5 .mu.m and smaller than 20 .mu.m, and wherein the charging device is a device for contacting a charging member with the surface of the photosensitive member and applying a voltage to the charging member to charge the photosensitive member.

Abstract: A photosensitive member to be used for an image-forming apparatus can effectively suppress its wettability of the surface relative to foreign objects adhering to it and reduce the load and the mechanism necessary for cleaning the surface so as to prolong the service life of the photosensitive member and make the apparatus adapted to down-sizing. For this purpose, the wettability (W: work of adhesion) of the surface of the photosensitive member relative to toner is confined to be between 60 and 110 mN/m.

Abstract: In a surface potential measuring apparatus for measuring a potential configuration by moving a photosensitive body of an image forming apparatus of electrophotographic type and at least one potential sensor relative to each other and by generating dielectric current in the potential sensor due to change in potential on a surface of the photosensitive body and by analyzing the dielectric current, a width of a detecting portion of the potential sensor is smaller than a width of the change in potential to be measured, and a sectional shape of the detecting portion in a plane perpendicular to the surface of the photosensitive body and parallel to the relative movement direction does not include any edge.

Abstract: An image-forming apparatus is provided which has a photosensitive member having improved temperature characteristics and improved electric properties and an ozoneless charging system in combination, and employs neither a heater nor a cleaning roller. In the apparatus, a charging member having a cylindrical multipolar magnetic body of 500 G or stronger and a magnetic brush layer formed from a magnetic powder on the peripheral surface of the magnetic body is allowed to rub the surface of a charging object in a reverse direction at a movement speed ratio of not less than 110% to charge the charging object. The charging object is a photosensitive member having a photoconductive layer composed of non-single-crystal silicon. The photoconductive layer contains hydrogen at a content ranging from 10 to 30 atomic %, and Si--H.sub.2 /Si--H at a ratio ranging from 0.2 to 0.5, having density of state ranging from 1.times.10.sup.14 cm.sup.-3 to 1.times.10.sup.16 cm.sup.

Abstract: The present invention provides a charge apparatus comprising a charge member to which voltage is applied for charging a member to be charged, the charge member having a bearing member for bearing a magnetic particle layer contacted with the member to be charged. The bearing member includes therein a plurality of magnetic poles disposed in a circumferential direction thereof, and the magnetic poles are arranged in a spiral fashion.

Abstract: An electrophotographic photosensitive member comprising a substrate, a light receiving layer having a photoconductive layer composed of a non-single crystal material containing silicon atoms as a matrix and having photoconductivity disposed on said substrate, and a surface protective layer disposed on said light receiving layer, characterized in that said surface protective layer comprises a metal oxide film formed by adjusting the surface of said light receiving layer to have a contact angle against water of 80.degree. or more, applying a sol liquid comprising an organometallic compound admixed with water, an alcohol and an acid onto the surface of said light receiving layer, and subjecting the resultant to heat treatment. An electrophotographic apparatus provided with said electrophotographic photosensitive member. A process for the production of said electrophotographic photosensitive member.

Abstract: There are provided an electrophotographic apparatus and an electrophotographic process featured by control satisfying a condition 1n(n).times.1n(S)/1n(E).ltoreq.19.0 among the localized energy level density n in the photoconductive layer of an amorphous silicon photosensitive member employed in the electrophotographic apparatus, the electric field E applied to the photosensitive member, and the surfacial moving speed S thereof. Such control reduces the photocarriers remaining in the photoconductive layer and inducing the photomemory effect, thereby suppressing the influence of a remaining latent image on the latent image generated in a next step, and providing an image of high quality without the photomemory effect, within resulting in a loss in the charging efficiency.