Abstract: In accordance with the present invention, a transparent or semitransparent window is formed in a developing device or a process cartridge to allow one to see the inside of the developing device via the window from the outside. The window may preferably be formed in the top wall of the developing unit or that of the process cartridge.

Abstract: An image forming apparatus includes at least one first image carrier that carries a chromatic color toner image formed thereon, a second image carrier that carries a black toner image formed thereon, at least one first gear that rotates to drive the first image carrier to rotate, a second gear that rotates to drive the second image carrier to rotate, and a control device that controls respective rotation stop-positions of the first and second gears. The control device controls the first gear and the second gear to stop rotating at positions different from rotation start-positions of the first gear and the second gear, respectively, while maintaining a predetermined phase relation between the first gear and the second gear in a color mode, and the control device controls the second gear to stop rotating at a position substantially equal to a rotation start-position of the second gear in a monochrome mode.

Abstract: In cases where the transfer positions of toner images of respective colors that are formed on respective photosensitive bodies show a positional deviation, the rpm values of driving parts that drive the photosensitive bodies are adjusted in accordance with the amount of the positional deviation so that the linear velocities of the photosensitive bodies are constant.

Abstract: A drive apparatus for a rotary member including a drive motor, and a drive shaft driven by the drive motor and having a first hole. The drive apparatus further includes a transmission member disposed around the drive shaft and configured to transmit the driving force to the rotary member by engaging with the rotary member. The transmission member includes a second hole extending in an axial direction of the drive shaft and being open toward a front side and closed toward a back side. A pin is inserted in the first and second holes. A spring presses the transmission member toward the rotary member.

Abstract: A driving device for driving a plurality of driven members of the present invention includes a first drive source for driving first one of the driven members. A second drive source drives second driven members other than the first drive member. An idler gear intervenes between the second driven members for transmitting the output torque of the second drive source. The second driven members are matched in rotation variation phase to each other during assembly.

Abstract: An image forming apparatus includes at least one first image carrier that carries a chromatic color toner image formed thereon, a second image carrier that carries a black toner image formed thereon, at least one first gear that rotates to drive the first image carrier to rotate, a second gear that rotates to drive the second image carrier to rotate, and a control device that controls respective rotation stop-positions of the first and second gears. The control device controls the first gear and the second gear to stop rotating at positions different from rotation start-positions of the first gear and the second gear, respectively, while maintaining a predetermined phase relation between the first gear and the second gear in a color mode, and the control device controls the second gear to stop rotating at a position substantially equal to a rotation start-position of the second gear in a monochrome mode.

Abstract: A transmission comprises a rotary shaft; a gear secured to the rotary shaft coaxially; and a regulative member secured to the rotary shaft. This regulative member press-contacts one end of the gear to maintain the gear exactly perpendicular to an axis of the rotary shaft. A photosensitive drum is fit to the gear. The regulative member is secured on the rotary shaft by press fitting.

Abstract: A drive apparatus for a rotary member including a drive motor, and a drive shaft driven by the drive motor and having a first hole. The drive apparatus further includes a transmission member disposed around the drive shaft and configured to transmit the driving force to the rotary member by engaging with the rotary member. The transmission member includes a second hole extending in an axial direction of the drive shaft and being open toward a front side and closed toward a back side. A pin is inserted in the first and second holes. A spring presses the transmission member toward the rotary member.

Abstract: A driving device for driving a plurality of driven members of the present invention includes a first drive source for driving first one of the driven members. A second drive source drives second driven members other than the first drive member. An idler gear intervenes between the second driven members for transmitting the output torque of the second drive source. The second driven members are matched in rotation variation phase to each other during assembly.