Abstract: A hybrid type image forming apparatus capable of forming a high quality image by using two image forming units having different resolution from each other, perform high throughput image forming by selecting most suitable image forming method or methods depending upon a kind of input image data, and reducing its running cost. In the apparatus, input image data of resolution of 300 dpi is separated into monochromatic image data and color image data. The monochromatic image data is converted into that of 600 dpi so that four pixels of an image of 600 dpi make one pixel of an image of 300 dpi. Then, a monochromatic image is formed on the basis of the monochromatic image data of 600 dpi by the image forming unit employing the electrophotograph method. A print medium on which the monochromatic image is formed is conveyed to the image forming unit employing the ink-jet printing method where a color image is formed on the basis of the color image data of 300 dpi.

Abstract: An image forming apparatus for forming an image on a recording medium includes a first conveying path for conveying a recording medium in order to form an image thereon using a first image forming device, a second conveying path for conveying a recording medium in order to form an image thereon using a second image forming device for forming an image according to an image forming method different from an image forming method of the first image forming device, a third conveying path for conveying a recording medium in order to form an image thereon using the first image forming device and the second image forming device, and a setting device for selectively setting one of a first conveying mode using the first conveying path, a second conveying mode using the second conveying path, and a third conveying mode using the third conveying path.

Abstract: An image fixing apparatus includes a fixing roller contactable to an unfixed image, and a back-up roller cooperable with the fixing roller to fix the unfixed image, wherein the back-up roller contains a fluorine surface active agent having an antistatic effect substantially to reduce electrostatic offset and enable the back-up roller to remove toner deposited on the fixing roller.

Abstract: An image forming apparatus for forming an image on a recording medium has an image forming system for forming an image on the recording medium, a second image forming system for forming an image on the recording medium based on an image forming method different from that for the first image forming system, a first recording medium transport passage for discharging the recording medium out of the apparatus after the recording medium has passed through the first and second image forming systems, a second recording medium transport passage for discharging the recording medium out of the apparatus without passing the recording medium through the second image forming system after the recording medium has passed through the first image forming system, and a third recording medium transport passage for discharging the recording medium out of the apparatus without passing the recording medium through the first image forming system after the recording medium has passed through the second image forming system.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic image; a developer carrying member, opposed to the image bearing member, for carrying a one component developer which is charged to a predetermined polarity by friction between the developer and the developer carrying member; an electric field generating device for generating, between the image bearing member and developer carrying member, an electric field for developing the electrostatic image on the image bearing member with a reverse development method; a regulating member for regulating an amount of the developer on the developer carrying member; and a voltage applying device for applying to the regulating member, a voltage having a polarity opposite the predetermined polarity.

Abstract: An image forming apparatus for forming an image on a recording medium includes a first transporting path for transporting the recording medium for forming an image on the recording medium by using a first image forming unit, a second transporting path for transporting the recording medium for forming an image on the recording medium by using a second image forming unit which forms the image by an image forming method which is different from a method employed by the first image forming unit, and a controller for controlling the apparatus in a black image selection mode, in which the first transporting path is selected in accordance with black image data for forming a black image on the recording medium, and the recording medium is transported through the selected first transporting path to form a black image on the recording medium, a color image selection mode, in which the second transporting path is selected in accordance with image data including color image data for forming a color image on the recording

Abstract: A developing apparatus includes a developer carrying member for carrying developer, an elastic blade press-contacted to the developer carrying member to regulate a layer of developer formed on the developer carrying member, where the elastic blade comprises an electrically conductive layer, and a high resistance layer located at the developer carrying member side of the conductive layer, and an electric field generating device for forming an oscillating electric field between the developer carrying member and the conductive layer, wherein a maximum intensity of the electric field is not less than 10.sup.6 V/m.

Abstract: An image forming apparatus which maintains proper fixing conditions through various situations. The apparatus includes a device for forming an unfixed image on a recording material; a fixing device for thermally fixing the unfixed image of the recording material; and a setting device for setting the fixing condition of the fixing device based on the number of image forming operations and the output of a temperature detecting element, which monitors the temperature of the heater in the fixing device.

Abstract: An image forming apparatus includes a movable image bearing member; an image forming device for forming an image on the image bearing member; a charging member disposed opposed to the image bearing member; and bias application device for applying a bias voltage to the charging member, wherein the bias applying device effects a constant voltage control to the charging member when an image area of the image bearing member is in a charging region of the charging member, and effects a constant current control during at least a part of a period in which an area of the image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.

Abstract: Disclosed is a fixing device using fuzzy inference, which is used for copying machine, optical printer, or the like. The fixing device is provided with a fixing heater drive circuit 13 for controlling a heater 8 arranged in a fixing roller 9 on the basis of signals from CPU 1. The CPU 1 executes fuzzy inference so as to maintain the heat amount within predetermined value.

Abstract: The present invention relates to a fixing apparatus having a pair of rotary members for pinching and conveying a supporting material bearing a non-fixed toner image thereon, thereby fixing the non-fixed toner image on the supporting material and wherein a rectifier element is connected to at least one of the rotary members in a predetermined orientation, whereby the present invention prevent a toner offset that the toner on the supporting material is adhered to the rotary members.

Abstract: An image forming apparatus includes a movable image bearing member; an image forming device for forming a toner image on the image bearing member; image transfer device for transferring the toner image from the image bearing member to a transfer material at an image transfer station, wherein the transfer device includes a charging member press-contacted or faced to the image bearing member and a device for applying a voltage to the charging member, wherein the voltage applying device applies a voltage to the charging member so that the charging member is constant-voltage-controlled when an image region of the image bearing member is in the transfer station, and the charging member is constant-current-controlled during at least a part of a period when it is not in the transfer station, wherein a voltage V2 applied during the constant voltage control is a voltage V1 appearing in the transfer device during the constant current control multiplied by a coefficient R, in which R is larger than 1.

Abstract: An image forming apparatus includes a movable image bearing member, an image forming device for forming the image bearing member, and an image transfer device contactable to the image bearing member at an image transfer position. The transfer device transfers the image formed by the image forming device onto a transfer material while the transfer material is conveyed through the transfer position together with the image bearing member, wherein the transfer device has a hardness of 20-40 degrees (Asker-C), and it is pressed to the image bearing member at a pressure of 50-200 g/cm.sup.2, and wherein a peripheral speed of the transfer device at the transfer position during a transfer operation is higher than a peripheral speed of the image bearing member at the transfer position.

Abstract: An image forming apparatus includes an image bearing member carrying an image corresponding to image information; an image transfer device for transferring the image on the image bearing member onto a transfer material at a transfer position, wherein the transfer device includes a charging member contactable to a back side of the transfer material and voltage application means for applying a voltage to the charging member, wherein the voltage applying device effects a constant voltage control to the charging member when an image region of the image bearing member is at the transfer position, and effects a constant current control to the charging member at least a part of the other duration, and wherein a voltage level of the constant voltage control is determined on the basis of a voltage across the transfer device during the constant current control; wherein voltage applied to the charging member by the voltage applying device or a current through the charging member by the voltage applying device is limited

Abstract: A charging device includes a contact member contactable to a member to be charged; and a voltage applying device for applying to the contact member a voltage having a level which periodically changes, to charge the member to be charged; wherein the voltage applying device constant-voltage-controls the contact member in a first period and constant-current-controls the contact member in a second period, wherein a voltage level in the first period is determined in the second period.

Abstract: An image forming apparatus includes a movable image bearing member; an image forming device for forming an image on the image bearing member; a transfer device for transferring an image from the image bearing member to a transfer material at a transfer position, wherein the transfer device is contactable to a backside of the transfer material at the transfer position and includes a charging member including a double oxide and a voltage source for applying a voltage to the charging member, and wherein the voltage source constant-voltage-controls the charging member when an image region of the image bearing member is at the transfer position, and constant-current-controls the charging member in at least a part of a period when the image region of the image bearing member is not at the transfer position, wherein a constant voltage for the constant voltage control is determined on the basis of the constant current control.

Abstract: An image transfer apparatus for transferring a toner image onto a transfer material includes an image bearing member for carrying a developed toner image; image transfer bias applying roller for contacting to a backside of the transfer material, for urging it to the image bearing member having the toner image and for applying a transfer bias to transfer the toner image to the transfer material; wherein amounts of charge applied to the transfer material by the transfer bias applying roller during its transfer operation satisfyA.gtoreq.B/2where A (Coulomb/cm.sup.2) is an amount of the charge at a portion where a surface potential of the image bearing member is relatively low, and B (Coulomb/cm.sup.2) is an amount of the charge at a portion where the surface potential of the image bearing member is relatively high. Then, disturbance to the image by the image transfer operation can be avoided.

Abstract: An image forming apparatus includes a device operable with a first rated voltage and a second rated voltage which is different from the first rated voltage, an image forming apparatus for forming an unfixed image on an image supporting member, a fixing device for fixing the unfixed image on the image supporting member, the fixing device including a heating roller heated by a heater and a back-up roller contacted to the heating roller, the rollers starting rotation under a predetermined condition, wherein the predetermined condition is different between when the apparatus is operated with the first rated voltage and when it is operated with the second rated voltage.

Abstract: There is disclosed an apparatus for obtaining image signal by tonal processing of an input signal. Pulse-width modulation of the input signal is achieved thorugh comparison with a second signal of a predetermined shaped, for example a triangular signal. In order to avoid the influence of fluctuating factors in pulse-width modulation, the apparatus also has a third signal generator, and the pulse-width modulated signal or a pattern signal generated by the third signal generator is selectively used for image formation.