Sharp Kabushiki Kaisha Corporation

Seiichi Yoshida

Fumio Shimazu

Hideki Ohnishi

Yoshie Iwakura

Kazuyuki Ohnishi

Tomohiro Oikawa

Toshihiko Takaya

A main controller controls drive of an LSU for irradiating laser light onto a charged photoreceptor, based on control data read from a non-volatile memory. The main controller causes the LSU to irradiate a beam of light onto the photoreceptor so as to form on the photoreceptor an electrostatic latent image corresponding to an image to be formed. A controlling section reads through an image reading section control data from the non-volatile memory at a different timing from a timing at which the main controller controls the LSU. The controlling section controls drive of the LSU based on the read control data.

Image forming apparatus with separate controllers for independently controlling an irradiating section

When a grounded conductive roller touches a transfer drum through a transfer material while a voltage is applied to a conductor layer, charges having a polarity opposite to the polarity of the voltage applied to the conductor layer are generated over the transfer material, thereby making it possible to attract the transfer material to the dielectric layer. Since the voltage is applied to the conductor layer, the electrostatic attraction of the transfer material and the toner transfer can be carried out using a single power source. Moreover, since the attraction of the transfer material and the toner transfer are carried out by the charge injection, a lower voltage can be used. Thus, the voltage can be readily controlled while reducing the ozone emission to a relatively low level. Furthermore, since the toner transfer and electrostatic attraction of the transfer material can be carried out using a single power source, the apparatus can be downsized and less expensive. In addition, when a semiconductor layer is made of a solid elastic body, a high-quality transferred toner image can be obtained without image quality deterioration.

Image forming method and apparatus

An image-forming apparatus is provided with: a photoconductor drum having a surface on which a toner image is formed, a transfer drum for transferring the toner image onto a copying material by allowing the copying material to contact the photoconductor drum, and a ground roller for electrostatically attracting the copying material onto the transfer drum prior to transferring the toner image onto the copying material. He transfer drum is constituted by a semi-conductive layer and a dielectric layer that are stacked on a conductive layer. [Supposing that] The nip width between the photoconductor drum and the transfer drum is L1, the rotation speed of the two drums is Vp, and the time constant, which is represented by a product of the resistance and the capacitance between the two drums, is .tau., the relationship represented by L1/Vp&lt;.tau. is satisfied. By defining the time constant of the transfer drum [as described above], it becomes possible to stabilize an electric field made by the transfer drum, and consequently to carry out a desired transferring operation.

Image-forming apparatus

An image forming apparatus is provided with a photosensitive drum on whose surface a toner image is formed, and image formation is carried out by transferring the toner image onto a transfer material such as paper or OHP sheet which is caused to electrostatically adhere to a surface of a transfer drum while being guided to the photosensitive drum. Alternatively, the toner image formed on the photosensitive drum may be once transferred onto an intermediate transfer drum, then transferred from the intermediate transfer drum onto the transfer material. In the image forming apparatus, a light projecting device for projecting light onto the photosensitive drum is provided on an upstream side to a toner image transfer position and on a downstream side to a development position on the photosensitive drum. Execution and suspension of the light projecting operation of the light projecting device is controlled depending on a toner type.

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Nara, Japan

Seiichi Yoshida