Sharp Kabushiki Kaisha Corporation

Osamu Nakayama

Masashi Hirai

Syoichiro Yoshiura

Fumio Shimazu

Hidekazu Sakagami

Noritaka Okazaki

Yuji Okamoto

Kozo Takahashi

Kiyoshi Toizumi

Takahiro Fukunaga

Kazuo Nakamura

Hideaki Hagihara

Masakiyo Okuda

Koichi Nakamura

Masayuki Ida

Toshiro Kurishita

In an image forming apparatus including a transfer and transport belt suspended between a plurality of rollers, an image forming section for forming a pattern image on the transfer and transport belt, and a pattern image detecting sensor for detecting the pattern image, the pattern image detecting sensor is disposed so as to detect the surface of a suspended segment, of the transfer and transport belt, suspended between the rollers, and a back surface contact member that is in contact with a back surface of a detection area where the pattern image detecting sensor detects the pattern image on the surface of the transfer and transport belt is provided so as to render the detection area flat and stable. This can provide an image forming apparatus incorporating a pattern image detecting means having a simple arrangement and a capability to surely detect the pattern image in a precise and stable manner.

Image forming apparatus

Photoreceptor drums for forming color images each have a gear as the drive transmission element at their central shafts. Each gear has an idle gear which in turn is coupled with a first motor via a timing belt. The photoreceptor drum for forming black monochrome images has a gear as the drive transmission element at its central shaft. This gear has an idle gear which is coupled with a second motor.

Apparatus for forming color images by the superimposition of visualized latent images having drive means for simultaneously driving at least a recording medium conveying means and a source of black visualized latent images

An image transfer roller cleaning system for operation in conjunction with a retractable image transfer roller in an image forming apparatus. A transfer belt extends through a gap between the transfer areas of a group of photoreceptor drums and corresponding image transfer rollers from an upstream side to a downstream side. The photoreceptor drums are arranged in parallel to one another. The transfer rollers urge the transfer belt into engagement with the respective transfer areas of the photoreceptor drums during the transport of a printing medium through the gap. A cleaning brush located upstream from the gap acts to clean the inner side of the belt prior to its entry into the gap. Cleaning blades also clean the outer surfaces of the transfer rollers when predetermined transfer voltages are not being applied thereto. In addition, the cleaning system may include features such as checking sensors and/or circuits for monitoring purposes. Applied voltage variation controllers for optimizing the quantity of toner carried by the photoreceptor drums also may be included. Further, image formation prohibiting controllers for preventing the formation of an image in those cases where the portions of the system checked by the checking devices register signal readings outside of predetermined ranges may be included. In addition, apparatus for moving the transfer rollers and/or the transfer belt wholly, or partially, out of their normal image transfer positions for cleaning purposes may be included.

Image forming device having image transfer component cleaning means

A sheet conveyance guide is configured of separation claws for separating the paper from a conveyer and transfer belt and a movable sheet guide for guiding the paper to a fixer entrance sheet guide. The separation claws are arranged on the upstream side of the movable sheet guide. The movable sheet guide is rotatable about a pivot shaft with its distal end abutted by gravity upon the upstream end part of the fixer entrance sheet guide. The separation claws and movable sheet guide are axially supported so as to rotate on pivots. The sheet conveyance guide moves together with the vertical movement of the conveyer and transfer belt while the abutment point of the separation claws upon the conveyer and transfer belt moves to the appropriate position.

Sheet conveying system

An forming apparatus of the present invention is provided with a waste-toner transport unit that is installed separately from a photoreceptor drum cartridge. The waste-toner transport unit is pivoted so that the photoreceptor drum cartridge is easily removed from a machine main body. This arrangement makes it possible to miniaturize the photoreceptor drum cartridge and to use the waste-toner transport unit repeatedly. In another image forming apparatus of the present invention, a developer-supplying container, a waste-toner container, and a waste-developer container for receiving excessive developer that has been overflown from the developer tank are integrally formed into a container unit. This arrangement makes it possible to reduce the volumes of the containers in accordance with the respective supplying quantities of developer. Further, a pressing mechanism is provided so that upon replacing the container unit, the developer tank is brought apart from and close to the photoreceptor drum simultaneously with the pivotal movement of the container unit. This arrangement makes it possible to reduce the number of steps that are taken in the replacing operation as well as to prevent misoperations such as caused by negligence of duty in pressing the developer tank toward the photoreceptor.

A sheet transporting apparatus, for transporting a sheet from a sheet supplying device to a sheet supplied device, includes a transporting path, through which the sheet is transported, and a plurality of driving rollers disposed along the transporting path. The plurality of driving rollers are adapted to independently rotate so as to transport the sheet through the transporting path by sequentially rotating in a prescribed manner based on a position of the transported sheet. The sheet transporting apparatus also includes a coupling device for selectively coupling and decoupling the driving rollers to each other. The sheet transporting apparatus further includes a device, such as a knob, for rotating one of the driving rollers.

Sheet transporting apparatus

A sheet resist apparatus disposed in a transporting path of a recording sheet transported from a sheet supplying unit to an image forming unit in an image forming apparatus, includes: a pair of first rollers disposed in the transporting path; a pair of second rollers disposed in the transporting path at a downstream of the first rollers; a first driving device for rotating the first rollers to transport the recording sheet toward the second rollers; and a second driving device for rotating the second rollers to transport the recording sheet, which is transported from the first rollers, toward the image forming unit in synchronization with a timing of image-formation of the image forming unit. The sheet resist apparatus further includes: a sensor disposed between the first rollers and the second rollers for detecting a tip of the recording sheet transported from the first rollers; and a control device for controlling the first and second driving devices on a basis of a result of detection of the sensor, such that the first driving device stops driving once before the tip of the recording sheet reaches the second rollers, and such that the first driving device resumes driving earlier than the second driving device starts driving by a predetermined time period.

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Nara, Japan

Osamu Nakayama