Abstract: A developing device to develop a latent image on a rotatable image bearer includes an upstream developing roller disposed opposite the image bearer at a first developing position, and a downstream developing roller disposed adjacent to and downstream from the upstream developing roller in a direction of rotation of the image bearer, disposed opposite the image bearer at a second developing position. Each of the upstream developing roller and the downstream developing roller has a most approachable surface that approaches closest to the image bearer and a most withdrawn surface that withdraws farthest from the image bearer. In a state in which a reference surface point of the image bearer is disposed opposite the most approachable surface of the upstream developing roller at the first developing position, the reference surface point opposes the most withdrawn surface of the downstream developing roller at the second developing position.

Abstract: An image forming apparatus includes a removable unit to be removably installed in the image forming apparatus, having a unit-side opening, a connectable device having an apparatus-side opening to be connected to the unit-side opening to send developer from one of the removable unit and the connectable device to the other, a receptacle disposed below the unit-side opening and the apparatus-side opening to receive and store developer dropping from above, and a drawer unit to be retractably drawn out from the image forming apparatus. The receptacle is united with the drawer unit to be drawn out from the image forming apparatus together with the drawer unit.

Abstract: A developing device includes a developer bearer, a developer regulator, a casing including an opposing face to oppose the developer bearer upstream from a developing range in a direction of rotation of the developer bearer, and first, second, and third seals. The first seal includes a first end secured to the casing and a second end to contact a latent image bearer upstream from the developing range in a direction of rotation of the latent image bearer. The second seal includes a first end secured to the opposing face of the casing, and a second end to contact the first seal upstream from the developing range. The third seal includes a first end secured to the opposing face of the casing, and a second end to contact developer on the developer bearer between the developer regulator and the developing range in the direction of rotation of the developer bearer.

Abstract: A toner bottle driving device control method includes driving one of multiple toner bottle driving devices connected to a single toner container at a time, detecting abnormality of a toner bottle driving device being driven, determining a first abnormality phase of the toner bottle driving device being driven when a number of times the abnormality is detected exceeds a threshold, inhibiting the toner bottle driving device being in the first abnormality phase from driving until the first abnormality phase is resolved, driving a drivable toner bottle driving device containing a non-empty toner bottle when the toner bottle contained in the toner bottle driving device being driven is determined as empty, determining that the multiple toner bottle driving devices are in a second abnormality phase when each of the multiple toner bottle driving devices is determined as being in the first abnormality phase, and inhibiting image formation.

Abstract: A toner bottle driving device control method includes driving one of multiple toner bottle driving devices connected to a single toner container at a time, detecting abnormality of a toner bottle driving device being driven, determining a first abnormality phase of the toner bottle driving device being driven when a number of times the abnormality is detected exceeds a threshold, inhibiting the toner bottle driving device being in the first abnormality phase from driving until the first abnormality phase is resolved, driving a drivable toner bottle driving device containing a non-empty toner bottle when the toner bottle contained in the toner bottle driving device being driven is determined as empty, determining that the multiple toner bottle driving devices are in a second abnormality phase when each of the multiple toner bottle driving devices is determined as being in the first abnormality phase, and inhibiting image formation.

Abstract: A powder supply device to supply powder to a supply destination includes a body, a single holder including multiple mounts on which multiple powder containers are removably mounted respectively, and a reservoir disposed in the body and below the single holder to store powder discharged from the multiple powder containers; and the single holder is removably attachable to the body of the powder supply device including the reservoir.

Abstract: A developing unit includes a developer bearer to bear developer on a surface thereof, first and second developer conveyors each having a spiral blade mounted on a rotary shaft thereof parallel to a rotary axis of the developer bearer to convey developer in opposite directions to each other. A developer drain hole is provided at a given height in a side wall of a second developer conveyance channel to face a communication opening across the second developer conveyor. The first developer conveyor rotates in a direction with its spiral blade rising between the rotary shaft of the first developer conveyor and the communication opening. Rotational phases of the first developer conveyor and the second developer conveyor are fixed and synchronized with each other to weaken momentum of developer flow generated by the first developer conveyor toward the developer drain hole via the second developer conveyor.

Abstract: A powder supply device to supply powder to a supply destination includes a body, a single holder including multiple mounts on which multiple powder containers are removably mounted respectively, and a reservoir disposed in the body and below the single holder to store powder discharged from the multiple powder containers; and the single holder is removably attachable to the body of the powder supply device including the reservoir.

Abstract: A powder feeding device includes a powder container, a feeding tank in communication with the powder container, a negative pressure room in communication with the feeding tank via a suction port communicating tube; an air suction device in communication with the negative pressure room via a negative pressure room communication tube; a suction port opening and closing unit that opens and closes the suction port communicating tube; a negative pressure room opening and closing unit that opens and closes of the negative pressure room communication tube; an output port opening and closing unit that opens and closes an output port of the feeding tank; and a controller that performs negative pressure generation control, powder supply control, and powder discharge control. Further, the controller simultaneously starts the negative pressure generation control and the powder discharge control.

Abstract: A powder feeding device includes a powder container, a feeding tank in communication with the powder container, a negative pressure room in communication with the feeding tank via a suction port communicating tube; an air suction device in communication with the negative pressure room via a negative pressure room communication tube; a suction port opening and closing unit that opens and closes the suction port communicating tube; a negative pressure room opening and closing unit that opens and closes of the negative pressure room communication tube; an output port opening and closing unit that opens and closes an output port of the feeding tank; and a controller that performs negative pressure generation control, powder supply control, and powder discharge control. Further, the controller simultaneously starts the negative pressure generation control and the powder discharge control.

Abstract: A powder feeding device includes a powder container, a feeding tank in communication with the powder container, a negative pressure room in communication with the feeding tank via a suction port communicating tube; an air suction device in communication with the negative pressure room via a negative pressure room communication tube; a suction port opening and closing unit that opens and closes the suction port communicating tube; a negative pressure room opening and closing unit that opens and closes of the negative pressure room communication tube; an output port opening and closing unit that opens and closes an output port of the feeding tank; and a controller that performs negative pressure generation control, powder supply control, and powder discharge control. Further, the controller simultaneously starts the negative pressure generation control and the powder discharge control.

Abstract: A powder feeding device includes a powder container, a feeding tank in communication with the powder container, a negative pressure room in communication with the feeding tank via a suction port communicating tube; an air suction device in communication with the negative pressure room via a negative pressure room communication tube; a suction port opening and closing unit that opens and closes the suction port communicating tube; a negative pressure room opening and closing unit that opens and closes of the negative pressure room communication tube; an output port opening and closing unit that opens and closes an output port of the feeding tank; and a controller that performs negative pressure generation control, powder supply control, and powder discharge control. Further, the controller simultaneously starts the negative pressure generation control and the powder discharge control.

Abstract: An image forming apparatus has a photoconductive drum or belt supporting a toner image, a transfer member transferring the toner image onto a recording medium, a transportation device transporting the recording medium to between the photoconductor and the transfer member, a charger charging a surface of the transfer member to the anti-polarity of the electric charge of the toner image, a rotation drive unit rotating the transfer member to the same direction of the recording medium transportation, a contacting/removing unit that contacts the transfer member to the image supported member for printing and removes the transfer member from the image supported member when not printing, and a drive force transferring/blocking unit that transfers the drive force from the rotation drive unit to the transfer member before print starting-up and blocking the drive force during printing.

Abstract: An electrophotographic printer capable of easily attaching and detaching a retaining means to retain the inside of a photoconductive drum to and from the photoconductive drum. A flange located on the extraction side of a photoconductive drum is provided with: a retaining means to support the photoconductive drum from the side of the inner circumferential face of the photoconductive drum. And an advance and retreat mechanism to advance and retreat the retaining means to and from the inner face of the photoconductive drum. The retaining means can be easily dismantled from the photoconductive drum by operating the advance and retreat mechanism, and thereafter extracting the flange from the photoconductive drum.

Abstract: According to one embodiment, an image forming apparatus includes an image carrier, a image forming unit, a measurement unit and a controller. The image carrier includes a central region on which a target image as an object of an image forming is formed and a peripheral region placed outward of the central region. The image forming unit forms a reference image on the peripheral region and the central region, before the image forming is started. Also, the image forming unit forms the target image on the central region based on a preset condition and a third reference image on the peripheral region, during the image forming. The measurement unit measures a physical quantity for the reference images.

Abstract: To provide a printer capable of minimizing the effect of a wrapping member, which is used for wrapping a recording form around a photoconductor, on image quality and realizing high image quality printing, a conveying roller 6, wrapping roller 8, and transfer units 36a and 36b are arranged so that a line La connecting a center Ca of a roller 38a and a transfer point Ta and a line Lb connecting a center Cb of a roller 38b and a transfer point Tb are inclined to a central line A-A and are almost symmetric to the central line A-A. When the wrapping width W of the form around belt photoconductors 32a and 32b is specified to 5 mm?W?25 mm, even when a wrapping roller is not arranged between printing units 30a and 30b, a fixed wrapping width of the form S around the belt photoconductors 32a and 32b is reserved.

Abstract: An image forming apparatus has a photoconductive drum or belt supporting a toner image, a transfer member transferring the toner image onto a recording medium, a transportation device transporting the recording medium to between the photoconductor and the transfer member, a charger charging a surface of the transfer member to the anti-polarity of the electric charge of the toner image, a rotation drive unit rotating the transfer member to the same direction of the recording medium transportation, a contacting /removing unit that contacts the transfer member to the image supported member for printing and removes the transfer member from the image supported member when not printing, and a drive force transferring/blocking unit that transfers the drive force from the rotation drive unit to the transfer member before print starting-up and blocking the drive force during printing.

Abstract: In a charging device having saw-tooth electrodes for generating corona discharges, an amount of dust, toner, or paper dust attached to the tip end portions of saw-tooth electrodes is reduced. First to third pairs of saw-tooth electrode plates are disposed in a side-by-side fashion along the periphery of a photosensitive drum in which the first pair is disposed at an upstream side with respect to a direction in which the photosensitive drum rotates, the third pair at a downstream side, and the second pair at a central portion between the remaining two. A current flowing per a unit length of the second pair is set to 1.3 to 3 times as much as a current flowing per a unit length of each of the first and third pairs. The currents flowing per a unit length of the first and third pairs are set to be equal to each other.

Abstract: An electrophotographic printer capable of easily attaching and detaching a retaining means to retain the inside of a photoconductive drum to and from the photoconductive drum. A flange located on the extraction side of a photoconductive drum is provided with: a retaining means to support the photoconductive drum from the side of the inner circumferential face of the photoconductive drum. And an advance and retreat mechanism to advance and retreat the retaining means to and from the inner face of the photoconductive drum. The retaining means can be easily dismantled from the photoconductive drum by operating the advance and retreat mechanism, and thereafter extracting the flange from the photoconductive drum.

Abstract: According to one embodiment, an image forming apparatus includes an image carrier, a image forming unit, a measurement unit and a controller. The image carrier includes a central region on which a target image as an object of an image forming is formed and a peripheral region placed outward of the central region. The image forming unit forms a reference image on the peripheral region and the central region, before the image forming is started. Also, the image forming unit forms the target image on the central region based on a preset condition and a third reference image on the peripheral region, during the image forming. The measurement unit measures a physical quantity for the reference images.