Ricoh Company, Ltd.

Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Ricoh Printing Systems, Ltd.

Toru Kikuchi

Shuho Yokokawa

Satoshi Aita

Souichi Nakazawa

Isao Watanabe

Hidenori Takayasu

Atsushi Miyamoto

Sho Sawahata

Masahiro Mizuno

Kunitomo Takahashi

Youichi Takeuchi

Hidenori Iwanaga

Soushi Kikuchi

Yuji Ohmura

Shigeo Nemoto

Yasuyuki Horie

Osamu Ohuchi

By executing low-speed conveyance of web by a web feeding mechanism before the printing operation begins, slack W, W, and Win the web located downstream of the guide rollers, and the slacked web is accumulated in the air loop portion, thereby completing the standby for printing. At that time, the amount of web conveyance (accumulation) is saved. Then, high-speed printing operation begins, and when the amount of printing has reached the amount of web conveyance saved, high-speed conveyance by the web feeding mechanism begins.

Web conveyance method and apparatus of tandem printing system

A continuous-sheet printing tandem electrophotography system for printing a continuous sheet includes first and second electrophotography units. A first size of the continuous sheet is measured before an image printed by the first electrophotography unit with a first parameter value is fused on the continuous sheet. A second size of the continuous sheet is measured after the image printed by the first electrophotography unit is fused on the continuous sheet. The second electrophotography unit then prints the continuous sheet with a second parameter value that is determined by a size difference between the first and the second sizes. The first and the second sizes include a page length and a page width of the continuous sheet. The parameter values include a print speed, a polygon mirror rotating speed, a video clock frequency, and a laser power.

Continuous-sheet printing tandem electrophotography system and method of printing a continuous sheet

A disclosed laser light intensity control device includes a semiconductor laser configured to scan a photoconductor by emitting laser beams and form an electrostatic latent image, a temperature detection circuit configured to detect a temperature of the semiconductor laser, a light intensity detection circuit configured to detect a light intensity of the laser beams emitted from the semiconductor laser, a first drive circuit configured to supply the semiconductor laser with a first current that drives the semiconductor laser, a second drive circuit configured to supply the semiconductor laser with a second current that is superimposed on the first current, and a control circuit configured to control the first drive circuit and the second drive circuit.

Laser light intensity control device, laser light intensity control method, and image forming apparatus

A method of diagnosing a state of a horizontal synchronizing signal is provided for an optical scanner, which includes a rotary polygon mirror having a rotation sensor, a control clock competing with a signal of the rotation sensor to control the rotary polygon mirror to a constant speed, a laser beam illuminating the rotary polygon mirror to be used in a scanning operation, and a scanning beam detector detecting the laser scanning beam at a prescribed position and outputting a horizontal synchronizing signal to trigger a control of the scanner. The method includes using the optical scanner, and presetting an effective period of outputting the horizontal synchronizing signal by counting the control clock for the rotary polygon mirror, the counting being triggered by a previous horizontal synchronizing signal.

Method of diagnosing a state of a horizontal synchronizing signal for an optical scanner

A printing system has a first printer apparatus for forming an image on a first plane of a web having no feed holes and a second printer apparatus provided at a post stage following the first printer apparatus for forming an image on a second plane of said web. The first printer apparatus (P ) is operable to form a position-alignment mark (Rm) at a predesignated position on each page of a web. This position-alignment mark is detected by mark detection means of the second printer apparatus (P ). Control means is provided for controlling the web transport speed so that both the generation timing of a web feed control signal (CPF-N signal) being generated with preset cyclic periods and the generation timing of a mark detection signal issued from the mark detection means through detection of the position-alignment mark are kept constant in phase.

Printing system

In order to provide an indication when it is necessary to exchange toner recovery container, an electrophotographic apparatus monitors the accumulated driving time of a toner supply drive unit, and a massage indicating 'exchange the toner recovery container' is displayed at the time when a toner supply switch is operated under state in which the accumulated driving time exceeds a preset value.

Method and apparatus for indicating time for exchanging toner recovery

A toner supply control system of the electrophotographic apparatus which includes a developing unit 3 for developing with a developer composed of toner and carrier; a toner hopper 4 for storing the toner; a toner empty sensor 7 for detecting the remainder of toner in the toner hopper 4; and a toner supply drive unit 5 for conveying toner from the outside of the apparatus into the toner hopper 4. Toner is conveyed from the outside into the toner hopper 4 by driving the toner supply drive unit 5 over a predetermined period of time without stopping the operation of the electrophotographic apparatus when the toner empty sensor 7 detects over a predetermined period of time that the remainder of toner in the toner hopper 4 is small. Then the existence of an output signal outputted from the toner empty sensor 7 indicating that the remainder of toner is small is detected, and a previous signal of toner shortage is output while the developing operation of the electrophotographic apparatus is being maintained in the case of existence of the output signal, and the shortage of toner is reported to an operator in accordance with the previous signal of toner shortage.

Toner supply control system for an electrophotographic apparatus

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Ibaraki, Japan

Toru Kikuchi