Matsushita Electric Industrial Co., Ltd.

Other

Array Printers Ab

Masahiro Aizawa

Noboru Katakabe

Akira Kumon

Akira Fukano

Katsutoshi Ogawa

Kenji Asakura

Masanori Yoshikawa

Yoshitaka Kitaoka

Hiroyuki Matsuo

Masaichiro Tatekawa

Hajime Yamamoto

Hiroshi Terada

Kazumasa Hayashi

Teruyuki Naka

Shunji Onobori

Junichi Nawama

Hiroshi Komakine

Hitoshi Hisada

Akira Ryoji

Akira Ryouji

An image forming device includes a developer carrier ( ) for carrying a charged developer ( ), and a developer passing controller ( ) for applying a voltage corresponding to an image. signal to a plurality of control electrodes ( ) to control the passing of said developer ( ), the developer passing controller having a plurality of developer passing holes ( ) through which the developer ( ) passes and said control electrodes being arranged to surround the surroundings of the developer passing holes. The width (W ) of a control electrode row ( ) in the longitudinal direction where the control electrodes ( ) are arranged is wider than the width (W ) of an image forming area, and both ends (B , B ) of the control electrode row ( ) in the longitudinal direction are arranged outside the width (W ) of an image forming area.

Image-forming device

A color image forming apparatus is provided, having a plurality of image forming units; a carriage for retaining and rotating the plurality of image forming units so as to move the image forming units between an image forming position and a waiting position; an intermediate transfer belt for successive transfer and superposition of toner images of various colors from a photosensitive drum of the image forming units located at the image forming position so as to form a color toner image; and a secondary transfer roller for transferring the color toner image on the intermediate transfer belt onto recording paper. The only rollers support the intermediate transfer belt are a driving roller, a following roller, a primary transfer roller and a backup roller, and the primary transfer roller and the backup roller are arranged adjacent to the driving roller.

Color image forming apparatus

In an image forming apparatus of the present invention, image signal electrodes are provided on a flexible printed circuit base in opposing relation to a developer carrying member such that they are disposed around the openings of developer passage holes, different voltages are applied thereto during dot formation and during non-dot formation, a throttle electrode is provided on the flexible printed circuit base in opposing relation to a counter electrode, a voltage always lower than the voltage applied to the image signal electrodes is applied to the throttle electrode when a developer of negative polarity is applied, and a voltage always higher than the voltage applied to the image signal electrodes is applied to the throttle electrode when a developer of positive polarity is applied.

Image forming device and image forming method

An image forming device includes a toner carrier ( ) for holding and conveying charged toner ( ), and a toner passage controller ( ) including a plurality of holes ( ) through which toner ( ) is passed and control electrodes ( ) disposed surrounding the holes. The control of passing of the toner ( ) through the holes is effected by applying voltage to the control electrodes in accordance with image signals. The holes ( ) have an elongated shape, with the length along a direction in which the toner carrier ( ) moves being longer than the width orthogonal to the lengthwise direction, so that the consumption areas of toner ( ) on the toner carrier ( ) do not interfere with each other while the open area of the holes ( ) is sufficiently secured.

Image forming device

A color image forming apparatus is provided, having a plurality of image forming units including a photosensitive drum, a charging device and a developing device; a carriage for retaining and rotating the plurality of image forming units so as to move the image forming units between an image forming position and a waiting position; an exposing device for exposing a surface of the photosensitive drum of the image forming unit located at the image forming position; an intermediate transfer belt for successive transfer and superposition of toner images of various colors from the photosensitive drum of the image forming units located at the image forming position so as to form a color toner image; a device for driving the photosensitive drum and the intermediate transfer belt; a position detector for detecting a reference position of the intermediate transfer belt when the intermediate transfer belt is driven; and outputting a reference position detection signal; a secondary transfer roller for transferring the color toner image on the intermediate transfer belt onto recording paper; and a controller for controlling the operation of the above structural elements. The controller determines an operation start time of the charging device and the developing device using a rotation command signal to the driving device as a reference, and an operation start time of the exposing device, the intermediate transfer belt and the secondary transfer roller using the reference position detection signal as a reference.

An image forming apparatus and an image forming method are characterized in that charged particle jumping can be controlled by applying signals having a small potential difference, and that low-voltage type switching devices can be used as switching devices for the power source. Control electrodes,are provided to move charged particles detached from a development roller,and to control the movement amount of the charged particles by generating a transfer electric field directly or indirectly between the development roller,and a rear electrode,. A bias electrostatic field is generated between the development roller,and the control electrodes,by applying a voltage under a jumping start voltage, which is a voltage having the polarity opposite to the polarity of the charged particles and is lower than the jumping start voltage for detaching the charged particles from the development roller

Image forming apparatus and image forming method

A color image forming apparatus is provided, and includes a plurality of image forming units including a photosensitive drum, a charging device and a developing device; a carriage for retaining and rotating the plurality of image forming units so as to move the image forming units between an image forming position and a waiting position; an exposing device for exposing a surface of the photosensitive drum of the image forming unit located at the image forming position; an intermediate transfer belt for successive transfer and superposition of toner images of various colors from the photosensitive drum of the image forming units located at the image forming position so as to form a color toner image; a drive member for driving the photosensitive drum and the intermediate transfer belt; a position detector for detecting a reference position of the intermediate transfer belt when the intermediate transfer belt is driven, and outputting a reference position detection signal; a secondary transfer roller for transferring the color toner image on the intermediate transfer belt onto recording paper; and a controller for controlling the operation of the above structural elements. The controller determines an operation start time of the charging device and the developing device using a rotation command signal to the driving means as a reference, and an operation start time of the exposing device, the intermediate transfer belt and the secondary transfer roller using the reference position detection signal as a reference.

In an image forming device wherein printing is accomplished such that passing of charged toners fed from a developer roller 2 through a plurality of openings 14 is controlled by control electrodes 16 of an aperture electrode 12 in accordance with image signals, toners held on the developer roller 2 are caused to reach the vicinity of the openings 14, by inputting a predetermined signal to the control electrodes 16 of the aperture electrode 12, at least once during the period when no image forming action in accordance with the prescribed image signals is performed.

Image forming method and device

A color image forming apparatus having a simple mechanism for switching plural photosensitive drum units and still maintaining a high resolution image is provided. In the apparatus, each image forming unit including each color photosensitive drum is disposed around a rotating shaft of a carriage. Each photosensitive drum has a coupling plate at one end, which is engaged by a drive side coupling plate for transmitting a drive force to the photosensitive drum, when the image forming units is moved to the image forming position. An output shaft that rotates the drive side coupling plate supports an edge of a photosensitive drum shaft in alignment. A toner image formed on the photosensitive drum is transferred onto a transfer belt, which rotates at a constant speed, one by one to form a multicolor image on the transfer belt. The multicolor image on the transfer belt is transferred onto a paper sheet. A transmission between a motor and the carriage include a worm gear.

Color image forming apparatus with plural color units

An electrophotographic apparatus includes a photoconductor drum, also known as an electrostatic latent image holding member, with a magnet placed therein. An electrostatic latent image is formed on the magnetic drum. Then, the drum is brought into contact with a magnetic developer, or toner, in a developer reservoir to have the magnetic developer attached to the photoconductor drum surface by a magnetic force. A removing roller, having an AC voltage applied thereto, is passed in close vicinity of the magnetic drum with the resultant development of images because toner remains at image areas only. In the electrophotographic apparatus, the photoconductor drum, the removing roller or both include two magnetic poles. A device for increasing friction force of the surface of the photoconductor drum, of the removing roller or both may also be provided.

Electrophotographic apparatus of improved low image density

An image forming apparatus according to the present invention includes: a photosensitive body; an exposing device for irradiating the photosensitive body with a light to form a latent image on the photosensitive body; a developing device for developing the latent image formed on the photosensitive body to form a developer image; a transfer roller for transferring the developer image on a recording paper; a fixing device for thermally fixing a transferred image on the recording paper after image transference; and a case for accommodating the photosensitive body, the exposing device, the developing device, the transfer roller and the fixing device, the case having at least six planes, two or more of the planes provided around an axis of the photosensitive body, being placement planes which are usable as a bottom during an image forming operation. The fixing device is always above the photosensitive body and the developing device, regardless of which plane is selected from the two or more placement planes as a bottom when the apparatus performs the image forming operation.

Image forming apparatus having a plurality of support surfaces

An image forming apparatus including a latent image carrying member moving while carrying an electrostatic latent image on a surface thereof; a developer supplying member for supplying a developer to a whole electrostatic latent image on the surface of the latent image carrying member including an image area and a non-image area; a charging member for charging the developer on the surface of the latent image carrying member; and a developer recovering member for recovering a portion of the developer adhering to the non-image area of the surface of the latent image carrying member.

Image forming apparatus and a charging device

A charging member for charging a photosensitive member from above toner in an electrophotographic process in which charging, exposure, development, and transfer steps are performed repeatedly and in which a step of cleaning toner remaining on a photosensitive member is eliminated, the charging member including: an electrically conductive charging wire which is disposed in contact with the photosensitive member; the charging wire forming an angle of less than 90.degree. with a direction of a rotational axis of the photosensitive member and is arranged at an interval in the direction of the rotational axis of the photosensitive member; and a power source for applying a pulse voltage to the charging wire, the pulse voltage having a polarity identical with that of the toner so as to vibrate the toner.

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Takatsuki, Japan

Masahiro Aizawa