Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Ricoh Printing Systems, Ltd.

Kunio Satoh

Takao Kumasaka

Shinya Kobayashi

Yuzuru Simazaki

Youji Hirose

Takao Umeda

Toru Miyasaka

Hisao Okada

Seiji Maruo

Atsushi Onose

Tomio Sugaya

Susumu Edo

A multi-beam image recording device is capable of recording high-quality high-resolution images without positional errors by exposing test patterns for measuring positional errors of beam spots of each laser beam in main and subsidiary scanning directions, calculating the positional errors of beam spots using a correcting device, controlling the quantity of exposure according to the result of calculation, and thus correcting the positional errors in main and subsidiary scanning directions.

Image recording device and an image recording system

An electrophotographic color printer exposes a photosensitive body to form an exposure pattern thereon. Toner material of two different colors is then applied to the exposure pattern by developers. The toner materials are subsequently transferred to a recording medium and fixed thereon. The toner materials are applied to the photosensitive body so that each of the two colors of toner materials have regions of two different thicknesses so they will have different thicknesses when applied to the recording medium. When two of the thicker regions are adjacent, the fixing of the toner materials will cause the toner materials of the two regions to mix. Thus, if the two adjacent thicker regions are of different colors, a third color will be produced. Toner material of further colors may also be transferred to the recording medium, by applying further toner materials to the same or another photosensitive body using further developers. The exposure pattern has a plurality of voltage levels having predetermined relationships to one another.

Image forming device for creating a color image having pixel elements of

A printing and binding system and method utilize an electrophotographic apparatus for performing a printing operation so that a plurality of booklets can be simultaneously printed and bound even if the quantity to be printed is not large. Rolled paper is cut in a pre-treatment portion i a direction in which the rolled paper is supplied, into sizes each corresponding to a desired booklet so as to prepare cut paper sheets, then the same pages of booklets of a number which can be printed are simultaneously printed on the cut paper sheets in a printing portion, and then the next pages of the booklets are sequentially printed on the next cut paper sheets. After the pages of a plurality of booklets which can be printed simultaneously have been printed, the printed paper sheets for a plurality of the booklets are conveyed to a post-treatment portion so as to be cut into individual booklets so that desired booklets are bound. If the required number of the booklets has not been bound, the aforesaid steps are repeated. The system thus constituted enables a plurality of booklets to be printed simultaneously and also enables the time taken to bound the booklets to be shortened.

Printing and binding apparatus

An image recording apparatus including a photosensitive medium. A voltage is applied between the photosensitive medium and a developing sleeve of a developing unit, and a current flowing between the photosensitive medium and the developing sleeve is measured to be converted into a pulse waveform which is then compared by a predetermined reference value. On the basis of the result of the comparison, a gap is determined between the photosensitive medium and the developing unit, which is then advanced or retracted toward or from the photosensitive medium in accordance with the determined gap. Owing to the recording method carried out by the image recording apparatus, the gap can be selectively determined by observing the current waveform pattern of the current flowing between the photosensitive medium and the developing sleeve while decreasing gradually the gap therebetween, whereby a relation between the gap and height of a magnetic brush can definitely be established. Since the gap can be set within a range from a value representing an initial contact state in which the magnetic brush starts to contact with the photosensitive medium to a value representing a wholly contact state in which the whole magnetic brush contacts with the photosensitive medium with the aid of a current curve of the current flowing between the photosensitive medium and the developing sleeve, a contacting force of the magnetic brush bearing on the photosensitive medium can be weakened.

Image recording method including determining a gap between a

An electrophotographic recording apparatus is provided having a reduced overall size. The space around a photosensitive member required for the developing unit to be located is minimized, more particularly, it i minimized in the lengthwise directional space. In the electrophotographic recording apparatus having a photosensitive member which moves at a predetermined speed; an exposure device for exposing the photosensitive member; a developing unit for developing an electrostatic latent image obtained by the exposure; and a transferring device for transferring a developed visible image to a recording paper sheet or the like, the developing unit is composed of developing devices, a plurality of supporting members for supporting the developing devices and an element for rotating the supporting members. The supporting members can be rotated while making a portion adjacent to a widthwise directional end of the photosensitive member to be a supporting point in a range from a state where the surface of the photosensitive member and the surface of a developing roll of each developing device run parallel to each other to a state where they are positioned substantially perpendicular to each other.

Electrophotographic recording apparatus having a plurality of developing

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Hitachi, Japan

Kunio Satoh