摘要:
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
摘要:
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.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The image forming apparatus further includes a member which charges the transfer paper in a polarity reversed to a polarity of the transfer drum, so that the transfer drum can attract the transfer sheet electrostatically in a satisfactory manner. The image forming apparatus further includes a charge control mechanism for controlling the amount of charges on the photosensitive drum. In addition the photosensitive drum has a voltage applying mechanism for applying a voltage to the internal surface of the drum.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. A nip time changing controller changes the amount of time that a transfer sheet is in the nip between the transfer drum and the grounded conductive electrode member.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The image forming apparatus further includes a member which charges the transfer paper in a polarity reversed to a polarity of the transfer drum, so that the transfer drum can attract the transfer sheet electrostatically in a satisfactory manner. The image forming apparatus further includes a mechanism for removing the charges on the surface of the transfer drum via a bias switching device and a cleaning device for cleaning the surface of the transfer drum so as to eliminate defects in a transferred image, thereby upgrading the quality of a resulting image. The cleaning device may be a blade having a particular engagement crossover between the blade and transfer drum.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The transfer drum includes the inner side conductive layer, a semi-conductive layer, and a dielectric layer provided on the surface of the drum. The dielectric layer can be made to adhere to the semi-conductive layer by thermally contracting this layer or the semi-conductive and dielectric layer can be made of a one-piece construction. In another embodiment, the dielectric's inner side can have projections and depressions in contact with the semi-conductive layer.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. A variable voltage is applied to a conductive layer provided on an inner side of the transfer drum so as to either transfer the image onto the transfer paper or attract the transfer paper to the transfer roller. The transfer voltage is lower than the attracting voltage. The voltage applied to the transfer drum for both transfer and attraction will be variable depending on a detected humidity or type of transfer paper. In addition, a manual adjusting device is capable of adjusting the transfer or attraction voltage. A grounded conductive electrode roller is pressed against a dielectric layer provided on an outer side of the transfer drum for providing potential difference between the conductive layer and the transfer paper.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The image forming apparatus further includes an upstream member or layer on the electrode member which charges the transfer paper in a polarity reversed to a polarity of the transfer drum, so that the transfer drum can attract the transfer sheet electrostatically in a satisfactory manner.
摘要:
An image forming apparatus includes a transfer drum which attracts and holds a transfer paper electrostatically. A voltage is applied to a conductive layer provided on an inner side of the transfer drum, and a grounded conductive electrode member is pressed against a dielectric layer provided on an outer side of the transfer drum through the transfer paper. A toner image formed on a photosensitive drum is transferred onto the transfer paper when the transfer paper is wound around the transfer drum and brought into contact with the photosensitive drum. The image forming apparatus further includes a member which charges the transfer paper in a polarity reversed to a polarity of the transfer drum, so that the transfer drum can attract the transfer sheet electrostatically in a satisfactory manner. The image forming apparatus further includes a mechanism for removing the charges on the surface of the transfer drum and cleaning the surface of the transfer drum so as to eliminate defects in a transferred image, thereby upgrading the quality of a resulting image.
摘要:
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.