Ricoh Company, Ltd.

Yuji Sawai

Shinichi Namekata

Kazuyuki Sugihara

Chikara Imai

Katsuya Kawagoe

Nobuyuki Koinuma

Toshiaki Motohashi

Itsuo Ikeda

Yoshio Takamiya

Koji Suzuki

Hajime Oyama

Tsuneo Kurotori

Hiromi Ogiyama

Manabu Mochizuki

Takashi Bisaiji

Toshiharu Hachisuka

Tadashi Fujii

Eiichi Akutsu

Toshio Nakahara

Hideo Yoo

By Noriko Tsuiki, A Legal Representative

Tsuiki, Deceased Harunobu

Hisayuki Ushiyama

Manami Tsuiki, Legal Representive

Tomohiro Tsuiki, Legal Representive

In an image formation apparatus, a voltage greater than a value, at which toner removal efficiency when a second cleaning device removes toner from an intermediate transfer body is maximum, is applied to a cleaning roller.

Image formation apparatus

In an electrostatic image forming apparatus, including a corona discharger located so as to face an image carrier on which a toner image is to be formed. When a paper or similar recording medium is brought between the image carrier and the discharger, the discharger effects corona discharge at the rear of the recording medium so as to charge the medium to a polarity opposite to the polarity of the toner image. The toner image is then transferred from the image carrier to the recording medium. A polarity switcher allows a voltage of substantially the same polarity as the toner to be applied to a discharge wire included in the discharger, and environmental sensing device allows this voltage to be changed based on temperature and humidity conditions. The apparatus is free from defective discharge and defective image transfer ascribable to the deposition of free or isolated toner on the discharger.

Electrostatic image forming apparatus capable of reducing defective

In an electrostatic image forming apparatus, including a corona discharger located so as to face an image carrier on which a toner image is to be formed. When a paper or similar recording medium is brought between the image carrier and the discharger, the discharger effects corona discharge at the rear of the recording medium so as to charge the medium to a polarity opposite to the polarity of the toner image. The toner image is transferred from the image carrier to the recording medium. A polarity switcher allows a voltage of substantially the same polarity as the toner to be applied to a discharge wire included in the discharger. The apparatus is free from defective discharge and defective image transfer ascribable to the deposition of free or isolated toner on the discharger.

Electrostatic image forming apparatus

An image forming apparatus which feeds a predetermined bias current smaller than a threshold current to a semiconductor included in digital optics at least during image formation so as to enhance response. During image formation, the apparatus maintains the bias current at an adequate value.

Image forming apparatus

An image-receiving sheet for use with an electrophotographic method, including a transparent support and an overcoat layer formed thereon is disclosed, in which the overcoat layer (i) includes a thermoplastic resin which has a fluidification initiation temperature lower than that of a toner for image formation to be employed or that of a resin for use in said toner, and (ii) is white and opaque from being in a porous state. Furthermore, an electrophotographic method using the above image-receiving sheet is also disclosed.

Image-receiving sheet for electrophotography and electrophotographic

A method of cleaning a transfer drum, which is located to face a photoconductive drum, to remove a toner left untransferred on a transfer film which is wound around the transfer drum. A fur brush rotatable in contact with the transfer drum for removing the toner from the drum and a toner collecting roller rotatable in contact with the fur brush for removing the toner from the brush are prepared. Before the fur brush begins cleaning the transfer film, the toner collecting roller collects the toner deposited on the fur brush. The fur brush is prevented from rubbing itself against a clamping section which is provided on the transfer drum for retaining a paper sheet. The transfer film is discharged while being cleaned. Before the transfer drum is cleaned, the photoconductive drum is cleaned twice or more.

Method of cleaning a transfer drum of an electrophotographic apparatus

A method of removing a film from a photoconductive element of a color copier or similar image forming apparatus. At a suitable time when an image forming mode operation for forming a toner image on the photoconductive element is not under way, an amount of cleaning agent great enough to scrape a film off the photoconductive element is transported to a region between the photoconductive element and a cleaning sleeve. Subsequently, the amount of cleaning agent to be transported to such a region is reduced. This sequence of steps is repeated a plurality of times.

Method of removing a film from an image carrier of an image forming

In a multicolor image-forming apparatus having a photoelectric sensor for detecting the amount of toner of an unfixed toner image adhering onto a photosensitive element, and a toner density sensor for detecting the density of a developer in a developing machine to form a multicolor image by overlapping the toner images having a plurality of colors, a color-balance control method comprises the steps of correcting a setting value of an output of the toner density sensor of the developing machine in accordance with the change in amount of toner adhering onto a photosensitive element detected by the photoelectric sensor with respect to a high density section; setting an allowable range of the toner density in advance in the developing machine with respect to the toner having at least one color; setting the amount of toner adhering onto a photosensitive element of the at least one color as a reference when the toner density is changed outside the allowable range; and correcting the amount of toner adhering onto a photosensitive element of the other color in accordance with the reference. With respect to a half-tone section, the output of the photoelectric sensor may be corrected by controlling the exposure amount. With respect to the high density section, the output of the toner density sensor may be corrected in a predetermined way when the toner density is changed.

Color-balance control method

A method of removing a film which undesirably forms on a photoconductive element or similar image carrier of an image forming apparatus such as an electrophotographic copier, printer or facsimile machine. The method is implemented by a cleaning device having a cleaning sleeve which removed toner particles remaining on the image carrier after image transfer. In a film removing mode which is executed when an image forming mode for forming a toner image on the image carrier is not under way, the cleaning sleeve is rotated at a lower speed than in an ordinary cleaning mode so as to feed a greater amount of cleaning agent to a cleaning region. The rotation speed of image carrier and that of the cleaning sleeve are controlled in such a manner as to feed a predetermined adequate amount of cleaning agent for the removal of a film to the cleaning region at all times.

Method of removing a film from an image carrier

A pressure sensitive adhesive toner for use in electrostatic photography which consists essentially of porous aggregates. Each aggregate consists essentially of a cluster of a multiplicity of individual granules of pressure sensitive adhesive substance, each granule being encapsulated by a coating film of a film-forming material. Particles of an inorganic or organic pigment and/or a magnetic substance are contained within the aggregate in the interstices between the granules and deposited on the surfaces of the encapsulated granules. The toner aggregates are free from a tendency to cohere, cake and agglomerate to each other. The toner can be readily pressure fixed, using a low impression pressure, onto a surface bearing an electrostatic latent image without causing any contamination thereon, thereby forming a distinct visible image.

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Yokohama, Japan

Yuji Sawai