Abstract: An image forming apparatus includes an image forming portion, a fixing portion, a temperature detecting portion, a measuring portion, a storing portion, and a controller. The controller is capable of setting a case that a start of feeding of a recording material is permitted after a lapse of a predetermined time need to measure a temperature rising rate of the fixing portion and a case that the start of feeding of the recording material is permitted, depending on a value relating to the temperature rising rate stored in the storing portion, at timing before the lapse of the predetermined time.

Abstract: An image forming apparatus including: a charging member configured to charge a photosensitive member at a charging portion by a charging voltage in which an alternate-current voltage is superimposed on a direct-current voltage; a transfer member configured to transfer a toner image formed on the photosensitive member to a recording material at a transfer portion; and a controller configured to control the charging voltage, a predetermined area of the photosensitive member passing through the transfer portion during a trailing edge of the recording material passing through the transfer portion, wherein the controller controls a value of a peak-to-peak voltage of the alternate-current voltage when the predetermined area passes through the charging portion to be larger than a value of a peak-to-peak voltage when an area that becomes the image area other than the predetermined area passes through the charging portion.

Abstract: A fixing device including a rotatable tubular film, a heater including a substrate and a heat generating resistor, the heater including a first surface in contact with an inner surface of the film and a second surface opposite to the first surface, the heater extending in a longitudinal direction of the substrate, and a heat conducting member extending in the longitudinal direction and including a heater contact portion in contact with the second surface. The heat conducting member includes a film contact portion at a position adjacent to the first surface, the film contact portion being in contact with the inner circumferential surface, and on one side in the longitudinal direction, the heat generating resistor extends outside of a longitudinal end portion of the film contact portion, and the heater contact portion extends outside of the film contact portion.

Abstract: An image forming apparatus including: a charging member configured to charge a photosensitive member at a charging portion by a charging voltage in which an alternate-current voltage is superimposed on a direct-current voltage; a transfer member configured to transfer a toner image formed on the photosensitive member to a recording material at a transfer portion; and a controller configured to control the charging voltage, a predetermined area of the photosensitive member passing through the transfer portion during a trailing edge of the recording material passing through the transfer portion, wherein the controller controls a value of a peak-to-peak voltage of the alternate-current voltage when the predetermined area passes through the charging portion to be larger than a value of a peak-to-peak voltage when an area that becomes the image area other than the predetermined area passes through the charging portion.

Abstract: An image forming apparatus includes image bearing members, cleaning blades for removing toner from corresponding image bearing members, and developing devices for developing an electrostatic latent image on corresponding image bearing members with toner. The image forming apparatus is operable in a monochromatic mode in which the toner image is formed only on a predetermined one of the image bearing members, and no image is formed on the other image bearing member. In a monochromatic mode operation, a controller starts to drive the plurality of image bearing members in synchronism with each other in a state that the other image bearing member is spaced from a belt and the predetermined image bearing member is in contact with the belt. The controller is capable of executing a supplying operation for supplying the toner from the developing devices to the cleaning blades by way of the image bearing members, respectively.

Abstract: An image forming apparatus includes a signal generating unit that stores information on a plurality of dither matrices preset in correspondence with the density level of toner to be attached to the photosensitive member and converts input image data based on the dither matrices to generate a driving signal. The signal generating unit stores information on a first dither matrix corresponding to a first density level and a second dither matrix corresponding to a second density level higher than the first density level. The first dither matrix includes a minute exposure area in which the exposure device is caused to emit light to attain a potential at which no toner adheres to the photosensitive member, and the second dither matrix includes a normal exposure area in which the exposure device is caused to emit light to attain a potential at which toner adheres to the photosensitive member.

Abstract: An image forming apparatus includes an image bearing member, an intermediary transfer belt containing an ion conductive agent, a secondary transfer member, and a charging device. With respect to the intermediary transfer belt, when a difference in number of digits (or in log value) between resistivity measured by using a metal probe and resistivity measured by using a sputtering electrode is ?M, a difference in number of digits (or in log value) between resistivity in a first environment and resistivity in a second environment higher than the first environment in temperature or humidity is ?E, a length of the secondary transfer portion with respect to the movement direction of the intermediary transfer belt is La, and a distance from the charging portion to the primary transfer portion with respect to the movement direction is Lb, the following relationship is satisfied: ?M??E?log(Lb/La).

Abstract: An image forming apparatus includes a signal generating unit that stores information on a plurality of dither matrices preset in correspondence with the density level of toner to be attached to the photosensitive member and converts input image data based on the dither matrices to generate a driving signal. The signal generating unit stores information on a first dither matrix corresponding to a first density level and a second dither matrix corresponding to a second density level higher than the first density level. The first dither matrix includes a minute exposure area in which the exposure device is caused to emit light to attain a potential at which no toner adheres to the photosensitive member, and the second dither matrix includes a normal exposure area in which the exposure device is caused to emit light to attain a potential at which toner adheres to the photosensitive member.

Abstract: An image forming apparatus includes a plurality of image bearing members; a belt for receiving toner images from the image bearing members and for transferring the toner image onto a transfer material; a controller for driving the image bearing members; and wherein the image forming apparatus is operable in a monochromatic mode in which the toner image is formed only on a predetermined one of the image bearing members, and no image is formed on the other image bearing member, wherein in a operation in the monochromatic mode, the controller starts to drive the plurality of image bearing members in synchronism with each other in a state that the other image bearing member is spaced from the belt, and the predetermined image bearing member is in contact with the belt.

Abstract: An image forming apparatus includes: an image bearing member, an intermediary transfer belt containing an ion conductive agent, a secondary transfer member, and a charging device. With respect to the intermediary transfer belt, when a difference in number of digits between resistivity measured by using a metal probe and resistivity measured by using a sputtering electrode is ?M, a difference in number of digits between resistivity in a first environment and resistivity in a second environment higher than the first environment in temperature or humidity is ?E, a length of the secondary transfer portion with respect to the movement direction of the intermediary transfer belt is La, and a distance from the charging portion to the primary transfer portion with respect to the movement direction is Lb, the following relationship is satisfied: ?M??E?log(Lb/La).