Abstract: An image forming apparatus capable of setting a plurality of image forming speeds includes a transfer unit configured to transfer an image formed on an image carrier onto a sheet, a paper feed unit configured to feed the sheet, and a control unit configured to control the conveyance speed of the sheet to accelerate and decelerate without stopping the sheet in a section between the paper feed unit and the transfer unit to synchronize the sheet with the image formed on the image carrier. The control unit changes paper feed timing from the paper feed unit according to the image forming speed if the image forming speed is predetermined.

Abstract: An apparatus includes a first rotation member, a second rotation member that rotates while being in indirect contact with the first rotation member via a medium or being in direct contact with the first rotation member without the medium, a first drive motor that drives the first rotation member, and a second drive motor that drives the second rotation member. In addition, a first control unit controls the first drive motor to cause the first rotation member to rotate at a constant rotation frequency, a second control unit controls the second drive motor, and a rotation frequency detection unit detects a rotation frequency of the second drive motor. The second control unit is configured to control a rotation frequency of the second drive motor based on the detected rotation frequency of the second drive motor such that the second rotation member is driven to accompany the first rotation member.

Abstract: An image forming apparatus includes first and second rotation members which are a plurality of rotation members for performing image formation and rotate in contact with each other. A first driving motor drives the first rotation member. A second driving motor drives the second rotation member. The obtaining unit obtains pieces of motor driving information about driving states of the first or second driving motor at respective relative driving speeds when the relative driving speed of the second driving motor with respect to the driving speed of the first driving motor is changed to a plurality of relative driving speeds. The control unit controls the driving speed of at least either the first or second driving motor in image formation to reduce the relative speed difference between the circumferential velocities of the first and second rotation members based on the pieces of motor driving information obtained by the obtaining unit.

Abstract: The image forming apparatus includes a fixing portion, a temperature detection element, and a power control portion. The power control portion is capable of setting a first power supply control mode for supplying power according to the detected temperature for each one control cycle, a second power supply control mode for supplying power according to the detected temperature for each one control cycle and a third power supply control mode for supplying predetermined power, and switches, immediately before a leading edge of the recording material enters the fixing portion, a state of supplying the power in the first power supply control mode to a state of supplying the power in the second power supply control mode, and then switches the state of supplying the power in the second power supply control mode to a state of supplying the power in the third power supply control mode.

Abstract: In full-color printing, one of first and second rotary members is activated with a time lag after the other of the first and second rotary members is activated such that the phase difference between the first and second rotary members is an adjusted phase difference. In addition, every time monochrome printing is performed, the time lag is changed.

Abstract: A secondary transfer motor drive control unit drives a secondary transfer motor such that an intermediate transfer belt and a secondary transfer roller satisfy a follower condition. When the follower condition is satisfied, a difference in the circumferential surface speeds of the intermediate transfer belt and the secondary transfer roller can be appropriately controlled to the extent that color misregistration and image defects do not easily occur.

Abstract: The image forming apparatus includes a fixing portion, a temperature detection element, and a power control portion. The power control portion is capable of setting a first power supply control mode for supplying power according to the detected temperature for each one control cycle, a second power supply control mode for supplying power according to the detected temperature for each one control cycle and a third power supply control mode for supplying predetermined power, and switches, immediately before a leading edge of the recording material enters the fixing portion, a state of supplying the power in the first power supply control mode to a state of supplying the power in the second power supply control mode, and then switches the state of supplying the power in the second power supply control mode to a state of supplying the power in the third power supply control mode.

Abstract: An image forming apparatus includes first and second rotation members which are a plurality of rotation members for performing image formation and rotate in contact with each other. A first driving motor drives the first rotation member. A second driving motor drives the second rotation member. The obtaining unit obtains pieces of motor driving information about driving states of the first or second driving motor at respective relative driving speeds when the relative driving speed of the second driving motor with respect to the driving speed of the first driving motor is changed to a plurality of relative driving speeds. The control unit controls the driving speed of at least either the first or second driving motor in image formation to reduce the relative speed difference between the circumferential velocities of the first and second rotation members based on the pieces of motor driving information obtained by the obtaining unit.

Abstract: A color image forming apparatus in which a positional displacement detection image and a light quantity adjustment image are formed within a one-rotation length of an image bearing member (intermediate transfer belt). A light-emission quantity when detecting density is determined on the basis of a detection result of a light quantity adjustment image formed within the one-rotation length using light-emission quantity that is provided when light is emitted to the positional displacement detection image. This allows, for example, image density control to be performed quickly while precision of the image density control is maintained.

Abstract: The image forming apparatus includes a fixing portion, a temperature detection element, and a power control portion, wherein the power control portion is capable of setting a first power supply control mode for supplying power according to the detected temperature for each one control cycle, a second power supply control mode for supplying power according to the detected temperature for each one control cycle and a third power supply control mode for supplying predetermined power, and switches, immediately before a leading edge of the recording material enters the fixing portion, a state of supplying the power in the first power supply control mode to a state of supplying the power in the second power supply control mode, and then switches the state of supplying the power in the second power supply control mode to a state of supplying the power in the third power supply control mode.

Abstract: In full-color printing, one of first and second rotary members is activated with a time lag after the other of the first and second rotary members is activated such that the phase difference between the first and second rotary members is an adjusted phase difference. In addition, every time monochrome printing is performed, the time lag is changed.

Abstract: A color image forming apparatus in which a positional displacement detection image and a light quantity adjustment image are formed within a one-rotation length of an image bearing member (intermediate transfer belt). A light-emission quantity when detecting density is determined on the basis of a detection result of a light quantity adjustment image formed within the one-rotation length using light-emission quantity that is provided when light is emitted to the positional displacement detection image. This allows, for example, image density control to be performed quickly while precision of the image density control is maintained.

Abstract: An image forming apparatus capable of setting a plurality of image forming speeds includes a transfer unit configured to transfer an image formed on an image carrier onto a sheet, a paper feed unit configured to feed the sheet, and a control unit configured to control the conveyance speed of the sheet to accelerate and decelerate without stopping the sheet in a section between the paper feed unit and the transfer unit to synchronize the sheet with the image formed on the image carrier. The control unit changes paper feed timing from the paper feed unit according to the image forming speed if the image forming speed is predetermined.

Abstract: An electrophotographic apparatus is equipped with one or more printing sections including a photoreceptor, a charger that electrically charges the surface of the photoreceptor, an optical scanning section that optically scans the surface of the charged photoreceptor with a laser beam, a developer that develops image areas formed by optical scanning, a toner hopper that supplies toner to the developer, and an image transfer unit that transfers the developed image to a recording member. In this apparatus, the developer and toner hopper can be mounted and demounted separately and a plurality of toner hoppers and developers are changeable according to the kinds of toner colors to be used. Thus, of the developers and toner hoppers is equipped with a device that outputs electric signals to detect the correspondences of the toner hoppers and the developers.

Abstract: An electrophotographic apparatus is equipped with one or more printing sections including a photoreceptor, a charger that electrically charges the surface of the photoreceptor, an optical scanning section that optically scans the surface of the charged photoreceptor with a laser beam, a developer that develops image areas formed by optical scanning, a toner hopper that supplies toner to the developer, and an image transfer unit that transfers the developed image to a recording member. In this apparatus, the developer and toner hopper can be mounted and demounted separately and a plurality of toner hoppers and developers are changeable according to the kinds of toner colors to be used. Thus, each of the developers and toner hoppers is equipped with a device that outputs electric signals to detect the correspondences of the toner hoppers and the developers.

Abstract: A vacuum boiler evaporator includes a sealed vacuum boiler vessel, a sealed vacuum condenser vessel which contains a partition that divides it into a first chamber and a second chamber that functions as a noncondensible gas collector, a conduit which connects the vacuum boiler vessel with the first chamber of the vacuum condenser vessel, a plurality of heat transfer tubes which extend through the first chamber and into the second chamber, and a return pipe which extends from the second chamber to the vacuum boiler vessel.