Ricoh Company, Ltd.

Tadahide Sawamura

Nobuo Kasahara

Takaaki Tawada

Fumihito Itoh

Fumiyo Kojima

Yoko Nakamura

Yukio Noguchi

Tosio Nakahara

Masayoshi Watanuki

Masayosi Watanuki

Tsutomu Shoji

An image forming apparatus having a single driving source to move a charging roller and a transfer roller to be in contact with and separated from a photoreceptor to place the charging member and the transfer member in various states in relation to the photoreceptor as the image forming apparatus demands. The single driving source includes first and second cams having a common axis of rotation. One cam is used to move the charging member and the other cam is used to drive the transfer member. The control system is provided with a device for recognizing the current positions of the charging member and the transfer member in relation to the photoreceptor and a device for prescribing future positions of the charging member and the transfer member in relation to the photoreceptor after having been driven. The apparatus further includes a controller which operates the driving source until the charging member and the transfer member come to a state prescribed as the state to reach after from the current position.

Image forming apparatus and its control system having a single device

A color adjustment apparatus for a color picture image reproducing machine, the apparatus includes a color chart for visually representing all real colors in terms of color elements of saturation and hue, and a touch-key for inputting color adjustment data to the color copying machine, the color adjustment data relates to one of the colors corresponding to a pressed point on the color chart.

Color adjustment apparatus for color copying machine

A control system for a color copier which sets up an adequate color copying time for any particular size of paper sheets. A color document is repeatedly scanned to sequentially expose a single photoconductive drum, which is rotated at a constant speed, to a plurality of separated color components. Each of the latent images is developed by toner complementary in color to the color component associated with the latent image, and sequentially transferred to a paper sheet. The control system includes a paper size setting circuit, a scanning sensor for sensing the start of a scanning, and a home sensor for sensing an instantaneous angular position of the transfer drum. A control circuit is constructed to determine a transfer start and a transfer end time in response to a paper size signal, an output signal of the scanning sensor, and an output signal of the home sensor, and to variably control the rotation speed of the transfer drum during the interval between the transfer start and transfer end times so as to register the leading end of a paper sheet loaded on the transfer drum and that of each of the toner images.

Image forming apparatus and control system therefor

An image forming apparatus has a latent image carrier for carrying an electrostatic latent image formed thereon. The electrostatic latent image is developed into a visible image which is transferred from the latent image carrier onto a transfer sheet in an image transfer region. The transfer sheet is held on a drum-shaped or a belt-shaped holder with the leading end clamped by a clamp. For efficient image formation, the holder is accelerated and decelerated while the transfer sheet is out of the image transfer region. When the transfer sheet with the transferred image thereon is sent to an image fixing device, the holder is accelerated and decelerated during an interval after the trailing end of the transfer sheet has left the image transfer region and before the leading end of the transfer sheet reaches the image fixing device. After the holder has been accelerated and decelerated, it is positionally adjusted when required.

Image forming apparatus

A control device for a color copier which sets up an adequate color copying time for any particular size of transfer papers. A color document is repeatedly scanned by a scanning optical system to sequentially expose a single photoconductive drum, which is rotated at a constant speed, to a plurality of separated color components. Each of the latent images electrostatically formed on the drum is developed by a toner which is supplied from a developing device and complementary in color to the color component associated with the latent image, the resulting toner images being sequentially transferred to a transfer paper which is held on and rotated together with a transfer drum. The control device includes a paper size setting circuit for setting the size of a transfer paper to be used before a copying operation, a scanning sensor for sensing the start of a scanning performed by the optical system, and a home sensor for sensing the instantaneous angular position of the transfer drum. A control circuit is constructed to determine a transfer start time and a transfer end time in response to a paper size signal outputted by the paper size setting circuit, an ouput signal of the scanning sensor, and an output of the home sensor, and to variably control the rotation speed of the transfer drum during the interval between the transfer start and transfer end times so as to align the leading end of a transfer paper loaded on the transfer drum and the leading end of each of the toner images formed on the photoconductive drum and different in color from each other.

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Tokyo, Japan

Tadahide Sawamura