Fujitsu Corporation

Fujitsu Isotec Limited

Yoji Houki

Akihiro Komuro

Shinichi Watarai

Tomokazu Akuta

Yoshihiro Tonomoto

Hiroki Ohba

Kiyohisa Yanagita

Akira Takahashi

Yukio Nishio

Takeo Kojima

Takashi Maekawa

Shunji Kitagawa

Yasuhiro Ite

Toshio Hino

Mamoru Hokari

Nobuyuki Hayashida

Hiroshi Kera

Megumi Yasuda

Tomohiro Nonomura

Mitsuhito Furukawa

Akio Nakanishi

Hiroji Uchimura

Masanao Nagakura

Makoto Matsuoka

Haruhisa Inagaki

Hirotoshi Ikuta

Yasunori Hamada

Kazuhisa Suetani

Yoshio Iino

A computer controlled printer is capable of printing at different print densities. This makes it possible to automatically determine an optimum print density according to a normal operational mode with serious consideration given to print quality and an economy operational mode with serious consideration given to operating costs, thereby decreasing the print consumables. The printer has a print mechanism section for printing papers according to print data and a print controlling section for controlling the print mechanism section. The print controlling section selects either a print density in a normal mode or a print density in an economy mode according to the normal/economy instructions and controls the print density of the print mechanism section correspondingly.

Printer with print density switching means

The present invention relates to an optical scanning unit used for exposing a photosensitive drum of an image forming apparatus to light, and an image forming apparatus using this optical scanning unit. This optical scanning unit comprises a light source; an optical scanning mechanism for scanning with light from the light source; a start detecting mechanism for detecting scan light of the optical scanning mechanism at an end portion of a scanning range of the scan light to detect beginning of light scanning; and a frame which has a higher rigidity than that of a frame of an image forming apparatus and to which the light source, the optical scanning mechanism and the start detecting mechanism are attached. The image forming apparatus comprises an endless photosensitive body; charging unit for charging the photosensitive body; an optical scanning unit for exposing the photosensitive body to light, including a light source, an optical scanning mechanism having the same structure as the aforementioned optical scanning unit; a developing unit for developing an electrostatic latent image formed on the photosensitive body by light exposure by the optical scanning unit; and a transfer unit for transferring a toner image on the photosensitive body onto a sheet. Alteration of the optical path of the optical scanning unit by external force applied is made smaller by making the frame of the optical scanning unit more rigid than that of the image forming apparatus.

Optical scanning unit and image forming apparatus using the same with

An image forming apparatus having a developing unit for developing an electrostatic latent image on a photosensitive drum with a one-component toner, consisting of an endless latent image carrier; an image forming unit for forming an electrostatic latent image on the image carrier; a developing unit, for causing the developing roller to contact the image carrier to develop the electrostatic latent image on the image carrier; a mechanism for driving the developing unit; a toner sensor for detecting the presence/absence of the toner in the developing unit; and an abutting/detaching mechanism for abutting or detaching the developing roller of the developing unit on or from the image carrier. According to one aspect of this invention, this apparatus further has a controller for executing an image forming mode to control image formation in response to an image forming instruction, and a developer supply mode for, with the developing roller set apart from the image carrier, driving the driving mechanism to supply the toner to the developing roller in accordance with an output of the toner sensor indicating an insufficient amount of the toner.

Image forming apparatus having contact type, one-component developing

Disclosed are an image forming method for checking pickup of a sheet on which an image is to be formed before correcting skewing of the sheet, and an image forming apparatus. This method comprises a first step of permitting a pickup roller to pick up a sheet from a sheet retaining unit and causing the leading edge of the sheet to abut against resist rollers; a second step of permitting a detecting mechanism to detect that the sheet has been picked up by the pickup roller; a third step of rotating the pickup roller by a predetermined amount according to the detection of the detecting mechanism; a fourth step of driving the resist rollers to feed the sheet and driving an image forming mechanism for forming an image on the sheet; and a fifth step of permitting the image forming mechanism to form an image on the fed sheet. The apparatus comprises a sheet retaining unit for retaining sheets; a pickup roller for picking up a sheet from the sheet retaining unit; resist rollers against which the leading edge of the sheet abuts; an image forming mechanism for forming an image on a sheet fed by the resist rollers; a detecting mechanism for detecting that the sheet has been picked up by the pickup roller; and a controller for rotating the pickup roller, then rotating the pickup roller by a predetermined amount according to a sheet detection output of the detecting mechanism, then stopping rotating the pickup roller, and then rotating the resist rollers.

Image forming method and apparatus with automatic skew control

A printer capable of operation in an economy mode as well as in a normal mode. The printer includes a print mechanism for printing in accordance with print data. The printer also includes a print controller which controls the print mechanism. The printer is provided with a mode of operation selector for selecting between a normal mode of operation in which the print quality is relatively emphasized and an economy mode of operation in which operating costs are relatively emphasized. The print controller controls the print density at a first level when the normal mode of operation has been selected and at a second reduced level when the economy mode of operation has been selected.

An optical beam apparatus includes a light emission device, a driver for driving the light emission device with the applied VIDEO signal, an integral circuit for estimating a drop of the quantity of light emited by the light emission device from the VIDEO signal applied, and a light output control circuit for controlling the driver in compliance with the estimated result so that the quantity of light emitted by the light emission device becomes constant.

Optical scanning with light quantity compensation

The image forming device of this invention is related to a device such as a duplicator, a printer, a facsimile or the like in which a printing operation is carried out by utilizing an electrophotographic recording system and an electrostatic recording system, wherein the device includes a plurality of consumable working parts including at least a developing unit, a drum unit, a fixing unit, and a transfer unit, and the device further includes a unit for integrating the working time of each of the working parts, a memory for storing the integrated working time of each working part, a lifetime setting unit in which a predetermined lifetime of each working part is set, and a generator for generating an exchange requirement signal for at least one of the working parts when the integrated working time of the working part reaches the lifetime of the part set in the lifetime setting unit, whereby an image forming device having a system in which these consumable working parts can be exchanged at correct intervals, regardless of the conditions of use, is provided.

Image forming apparatus having an exchangeable unit exchange timing

A skew of a print medium sheet generally occurs when the sheet is fed to an image-forming area in an image-forming apparatus, for example, an electronics image-forming printer, from a pile of such sheets. An apparatus according to the present invention is provided with a plurality of pairs of feed rollers between the pile and the image-forming area, and a skew of a sheet is corrected every time the sheet comes in contact with each pair of rollers which are not rotating for a predetermined time, so that even a large skew can be corrected by the time the sheet reaches the image-forming area.

Method of separately feeding a print medium sheet and apparatus therefor

A developing unit of an electrophotographic apparatus is provided for developing an electrostatic latent image formed on an image forming member, by electrostatically adsorbing powder developer onto the latent image. The developing unit includes a screw provided with paddles or grooves, each having a helix angle with respect to an axis of the screw, the screw transferring and supplying the powder developer stored in a developer reservoir to the developing roller; a blade for regulating a layer thickness of the powder developer to be transferred to the image forming member; and a flow regulating plate for biasing a flow of the powder developer, which has been removed by the blade and returned to the developer reservoir due to the force of gravity, in a direction opposite to a direction in which the powder developer is transferred by the screw. The developing unit further includes a structure for accurately positioning and maintaining the developing roller within a specified distance from the image forming member, thereby improving the uniformity of the developer concentration.

Developing unit of electrophotographic apparatus

Growing community of inventors

Kawasaki, Japan

Yoji Houki