Minolta Camera Kabushiki Kaisha

Minolta Camera Co., Ltd.

Toshio Yamamoto

Shizuo Yuge

Isao Iizaka

Susumu Sakakibara

Osamu Miyamoto

Takashi Hikosaka

Takuma Ishikawa

Shigemitsu Shimizu

Shigemitu Shimizu

Michiru Kanesaka

Nobuo Kitou

Nobuo Kito

The disclosure is directed to an improved electrostatic latent image developing method in which uneven development arising from simultaneous employment of a magnetic roller rotational driving system and an AC developing bias impressing system is eliminated, without impairing the advantages available from such systems, so as to make it possible to provide developed images of good quality at high density in the application, for example, to an electrophotographic copying apparatus and the like.

Method of developing electrostatic latent images

An improved reversal development method of visualizing an electrostatic latent image through reversal development, including the steps of: forming a magnetic brush around an outer circumferential surface of a developing sleeve by the use of a developer composed of high-resistivity toner having a resistance value of 10.sup.13 .OMEGA.cm or more under an electric field of 10.sup.4 V/cm and a charge amount of 5 to 15 .mu.Q/g per unit mass generated by gaseous discharge; and applying simultaneously an a.c. bias, and a d.c. bias approximately equal to a sum of a potential of an image portion of the electrostatic latent image and a potential of its non-image portion to the magnetic brush.

Reversal development method of electrostatic latent image by the use of

A waiting time display system specifically for use in a copying machine includes a temperature sensor for monitoring the specific temperature of heat fixing rollers. Electronic processing is responsive to the varying signal outputs of the sensor and correspond to the rise of the temperature detected. A display panel is driven so that a plurality of lights are sequentially activated and deactivated to indicate time and temperature. An audio signal can also be provided to indicate the machine can be activated for copying. An operator can now gauge the amount of time until the copy machine is capable of being operative.

Pre-operative time display system for copying machines

A magnetic brush developing apparatus for use in a toner powder image transfer type electrophotographic copying machine which includes an outer cylinder fixedly disposed at a position to confront a photosensitive member or photoreceptor, a magnet roller rotatably accommodated in the outer cylinder for being rotatably driven, a toner tank or hopper containing therein electrically conductive and magnetically attractive toner particles having high resistance and disposed above the outer cylinder for supplying the toner particles onto the outer cylinder, an excessive developing region for developing an image portion of an electrostatic latent image formed on said photosensitive member with sufficient density, and a toner removing region for removing toner particles adhering at least to non-image portion of the electrostatic latent image.

Magnetic brush developing apparatus

An electrostatic latent image transfer type copying apparatus which has a photoconductive member, a system for forming an electrostatic latent image on the photoconductive member, an image transfer system for conducting transfer material having an insulating dielectric layer coated over an electrically conductive layer into contact with the photoconductive member for transferring the latent image onto said transfer material, a transporter for the transfer material to transport it along a predetermined path to the image transfer system, a member such as a relatively sharp edge member like a cutter provided along the path and below which the insulating dielectric layer side of the transfer material passes, and an insulating member provided adjacent the sharp edge member for preventing the surface of transfer material from contacting the sharp edge member as the transfer material is transported, whereby the contact of the sharp edge member with the surface of transfer material which causes frictional charging on the transfer material is substantially prevented.

Electrostatic latent image transfer type copying apparatus

Photocopying machine comprising shield elements which are provided between an electrophotosensitive medium and a corona discharge unit at a transfer station, define a slit to permit transfer of conductive toner particles onto copy paper charged by the corona discharge unit but prevent imposition on the paper of a charge liable to cause early transfer of toner particles or of a charge liable to cause cancellation of the charge of the toner particles, and hence detachment, of toner particles on the copy paper.

Conductive toner transfer photocopying machine

Apparatus for improving the quality of images obtained in an electrostatic latent image transfer type copier according to which there are provided electrical circuits permitting escape or neutralization of charges which may be produced in copy paper during its transport through a photocopying machine and could cause smudging or elimination of required image portions in developed copy paper carrying the image of a document or similar material. In the disclosed embodiment, the electrical circuits maintain each of the rollers of pairs of copy sheet transporting rollers at an equal potential.

A dielectric layer of copy paper is brought into contact with an electrostatic latent image bearing surface of a photosensitive plate by a first roller having an electric resistance value substantially higher than the rear face resistance value of the copy paper, the photosensitive plate having on its front face a dielectric layer for forming the latent image thereon and driven by a grounded roller. An electrically conductive lining element of the copy paper is substantially grounded by an electrically conductive second roller to transfer the electrostatic latent image by air breakdown discharge under the influence of the first and second rollers. The gap between the photosensitive plate and the copy paper has a width for air breakdown discharge according to Paschen's law.

Growing community of inventors

Toyokawa, Japan

Toshio Yamamoto