Fujitsu Corporation

Fuji Xerox Co., Ltd.

Fujitsu Isotec Limited

Takeo Kojima

Hirofumi Nakayasu

Tsutomu Nagatomi

Youji Houki

Morihisa Kawahara

Kouichi Kobayashi

Yoshihiro Watanabe

Fumihiro Itoh

Hiroji Uchimura

Masahiro Wanou

Shinji Sato

Akira Takahashi

Nobuyuki Tanaka

Masakazu Kinoshita

Yoshio Yamaguchi

Takao Sugano

Yoji Houki

Yoshihiko Taira

Hiroshi Kera

Michio Shimura

Hidenori Fujioka

Tsutomu Kawai

Mitsuhito Furukawa

Kazuhiro Tamada

Hiroyuki Kaneda

Susumu Imado

Makoto Matsuoka

Akihisa Sota

Kazuhiko Hamazoe

Kaneastu Uchiyama

Masakazu Kanaka

Shinichirou Yamamoto

Ryouhei Iwasaki

Kouji Kobayashi

Masao Konisi

In a recording device, electrostatic recording units of Y, M, C and K are arranged along the direction of the feed of a recording sheet by a belt unit. The device forms latent images corresponding to image data by optical scanning of an exposure device onto a rotating photosensitive drum, develops the latent images with toner components having different colors, and then transfers the developed images onto the recording sheet on the belt unit. A color matching processing unit performs color matching processing including color slippage correction of different color images. An automatic color matching mode processing unit works the color matching processing unit when conditions beforehand decided in the state that an automatic correction mode is set up are realized. A manual color matching mode processing unit controls the color matching processing unit when the manual color matching mode processing unit recognizes operator's manual color matching instructing operation in the state that a non-correction mode is set up.

Electrophotographic recording device

In a image forming apparatus, a lifespan copy number (lifespan time period) previously determined for each component is added to the replacement schedule copy number (replacement schedule time) of respective components contained in the apparatus, in other words the total print number (total print time) at the time of replacement of a component, and the resulting value is recorded in a non-volatile memory. Therefore, it is judged that a component lifespan has expired, each time that the total print number (total print time) exceeds the replacement schedule copy number (replacement schedule time period). Thereby, since the amount of information required for component lifespan management is small, the capacity of the non-volatile memory can be reduced, and hence cost reductions in the image forming apparatus can be achieved.

Image forming apparatus

The ratio detecting unit detects, upon stoppage of printing, a fixing control ratio K which represents a ratio of time during which the fixing unit was controlled to the printing temperature in a certain period of time in the past. The predicting unit predicts a fan driving time Tf after stoppage of printing in response to the thus detected fixing control ratio K. The fan control unit rotation-controls the cooling fan,during printing, keeps the fan controlling status for printing for a fan driving time Tf upon stoppage of printing, and upon lapse of the fan driving time Tf, fan stoppage or high-speed rotation is switched over to low-speed rotation.

Cooling unit and method of cooling an electrophotographic apparatus

To provide an electrophotography apparatus with which the service life management of a printing unit can be carried out properly, a non-volatile memory for storing a count value for managing the service life of the printing unit is installed in both a main unit and the printing unit of the electrophotography apparatus. Then, the count value is written to the memory on the printing unit (PU) side (PU memory) when print processing is not in progress, and no power is supplied to the PU memory during print processing, so the correct count value is always stored in the PU memory. Therefore, the service life of the printing unit can be correctly evaluated.

Electrophotography apparatus

An image-forming device such as a full color printer is provided which is designed to correct the speed of a conveyer belt on which print sheets are transported or intervals between image-transferring units for compensating for a shift between colors. The image-forming device has a timer which measures an elapsed time from turning on of the device or release of a sleep mode, a print-off time and a print time and determines a correction value as a function of the times measured by the timer by look-up using a table.

Disclosed is a toner residual quantity detecting apparatus for detecting a residual quantity of toners in a developing unit. This toner residual quantity detecting apparatus has a temperature sensor, provided in the bottom of the developing unit, for generating an output proportional to a detected temperature and a detecting circuit for detecting the toner residual quantity from the output of the temperature sensor. This temperature sensor detects a difference between temperatures when covered with the toners and when not covered with the toners, thereby detecting the toner residual quantity.

Apparatus for detecting residual quantity of toners

An image forming apparatus includes a transport mechanism transporting a recording medium on a belt which is transported at a constant speed in a transport direction, a plurality of electrostatic recording units arranged in the transport direction of the recording medium and transferring toner images of different colors, a positional error detecting part using the toner image of a reference color transferred by one of the electrostatic recording units as a reference image, and relatively detecting positional error information related to positional errors of the toner images of remaining colors transferred by the remaining electrostatic recording units with respect to the reference image, and a positional error correcting part relatively correcting the positional errors of the toner images transferred by the remaining electrostatic recording units based on the positional error information. The positional error detecting part includes a part for controlling the electrostatic recording units to transfer at least two resist marks on the belt at a scan starting end and a scan terminating end of the belt in a main scan direction which is perpendicular to the transport direction of the recording medium, with respect to each of the colors, and a second part, including a sensor detecting the resist marks, for detecting positional error quantities of the resist marks of each of the remaining colors with respect to the resist marks of the reference color based on detection times of the resist marks of reference color and the remaining colors.

Positional error correction for color image forming apparatus

A drum phase correction unit for detecting rotational positions of a plurality of photosensitive drums by means of a plurality of drum position sensors and corrects to set rotational phases of the drums to predetermined phases in such a manner that transfer positions on drum circumferential surfaces relative to a belt when employing the thus detected rotational positions as their respective references have a specific relationship including coincidence. A positional offset detection unit detects positional offsets of transfer image on recording paper attributable to the wow and flutter in a drive system including the belt and the photosensitive drums. On the basis of the thus detected positional offsets, a wow and flutter correction unit corrects the positional offsets of the transfer images on the recording paper attributable to the wow and flutter.

Printing apparatus

A toner developing quantity detection unit operates a plurality of electrostatic recording units to transfer Y, M, C and K color component toner marks onto a belt. A toner developing quantity correction unit detects toner developing quantities per unit area of color toners on the basis of detection signals of the color component toner marks on the belt optically detected by a sensor. The toner developing quantity correction unit corrects the toner developing quantities so as to allow the toner consuming quantities of the plurality of electrostatic recording units to be substantially the same level, on the basis of the thus detected toner developing quantities.

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

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Kawasaki, Japan

Takeo Kojima