Abstract: A paper conveying apparatus and an image forming apparatus are described which can appropriately convey a sheet when the sheet is restarted after forming a loop. The paper conveying apparatus includes a conveying roller pair in the upstream side of a loop roller pair, a stepping motor for rotationally driving the conveying roller pair, and a processor for controlling rotation of the stepping motor by controlling pulse signals and excitation current supplied to the stepping motor. This processor halts rotation of the conveying roller pair by stopping output of the pulse signals when loop formation of the sheet is completed, and switches the excitation current to a lower current value which is lower than a reference current value at which excitation is turned on.

Abstract: A paper conveying apparatus and an image forming apparatus are described which can appropriately convey a sheet when the sheet is restarted after forming a loop. The paper conveying apparatus includes a conveying roller pair in the upstream side of a loop roller pair, a stepping motor for rotationally driving the conveying roller pair, and a processor for controlling rotation of the stepping motor by controlling pulse signals and excitation current supplied to the stepping motor. This processor halts rotation of the conveying roller pair by stopping output of the pulse signals when loop formation of the sheet is completed, and switches the excitation current to a lower current value which is lower than a reference current value at which excitation is turned on.

Abstract: An image-forming apparatus contains an image-forming portion, a first conveying portion that is arranged at an upstream side of the image-forming portion along a sheet conveying direction, a second conveying portion that is arranged at an upstream side of the first conveying portion along the sheet conveying direction and a control portion. The control portion controls the first conveying portion to move a pair of registration rollers along a direction that is orthogonal to the sheet conveying direction while the pair of registration rollers nips the sheet when conveying the sheet to the image-forming portion. The control portion controls the second conveying portion to move one of the pair of conveying rollers along the direction that is orthogonal to the sheet conveying direction while the pair of conveying rollers does not nip the sheet.

Abstract: An image-forming apparatus contains an image-forming portion, a first conveying portion that is arranged at an upstream side of the image-forming portion along a sheet conveying direction, a second conveying portion that is arranged at an upstream side of the first conveying portion along the sheet conveying direction and a control portion. The control portion controls the first conveying portion to move a pair of registration rollers along a direction that is orthogonal to the sheet conveying direction while the pair of registration rollers nips the sheet when conveying the sheet to the image-forming portion. The control portion controls the second conveying portion to move one of the pair of conveying rollers along the direction that is orthogonal to the sheet conveying direction while the pair of conveying rollers does not nip the sheet.

Abstract: Provided is an image forming apparatus having a fixing device for fixing an image at a nip portion formed of two rotary members which rotate while facing each other, wherein occurrence of uneven print gloss is prevented. The image forming apparatus having a fixing device for fixing an image at a nip portion formed of two rotary members which rotate while facing each other, wherein one of the two rotary members is a belt which rotates while being stretched around of a plurality of rollers, a roller arranged at the exit of the nip portion out of the plurality of rollers has a crown shape, and a slack absorbing member for absorbing a slack of both ends of the belt caused by the crown-shaped roller is in contact with the belt.

Abstract: Provided is an image forming apparatus having a fixing device for fixing an image at a nip portion formed of two rotary members which rotate while facing each other, wherein occurrence of uneven print gloss is prevented. The image forming apparatus having a fixing device for fixing an image at a nip portion formed of two rotary members which rotate while facing each other, wherein one of the two rotary members is a belt which rotates while being stretched around of a plurality of rollers, a roller arranged at the exit of the nip portion out of the plurality of rollers has a crown shape, and a slack absorbing member for absorbing a slack of both ends of the belt caused by the crown-shaped roller is in contact with the belt.

Abstract: An image forming apparatus includes: an image forming section for forming a toner image on a sheet; a fixing device for fixing the toner image on the sheet with heat; a reversal conveyance section which reverses a conveyance direction of the sheet which has passed through the fixing device; a conveyance member provided at the reversal conveyance section which is changed to be in either one of a conveyance state in which the conveyance member is in contact with an image supporting surface of the sheet, and to be in an evacuated state in which the conveyance member is separated from the image supporting surface of the sheet; and a switching mechanism for switching the conveyance member to be in one of the conveyance state and the evacuated state.

Abstract: By providing a rib formed to be inclined with respect to the conveyance direction on a guide member provided at the upstream side of the conveyance section where a contact member that cools rapidly the sheet subjected to fixing processing is provided, a problem of the occurrence of uneven gloss on the surface of a toner image by contact between a sheet and a guide member or a conveyance roller in a conveyance section that conveys the sheet subjected to fixing processing is solved.

Abstract: An image forming apparatus provided with a bent sheet feeding guide member in the transportation path for transporting the recording material with the inclination along the width direction of the guide surface configured by the bent sheet feeding guide member being variable, or provided with a pair of transporting rollers that transports a recording material in the transportation path for transporting a recording material with the inclination of the pair of transporting rollers along the axial direction being variable with respect to the transportation surface.

Abstract: In the discharge section to correct the potential of toner image on the intermediate transfer body before the secondary image transfer and to obtain a good secondary transfer image, it is made that the opposite electrode is brought into contact with the back surface of the intermediate transfer body under the stable condition.

Abstract: The present invention provides an image printing apparatus which comprises registration roller unit which convey an image recording sheet toward an image transfer position at which the toner image is transferred onto the image recording sheet, a sensor which is provided between the registration roller unit and the image transfer position to detect the image recording sheet, and a control unit which controls driving of the registration roller unit.

Abstract: An image forming apparatus provided with a bent sheet feeding guide member in the transportation path for transporting the recording material with the inclination along the width direction of the guide surface configured by the bent sheet feeding guide member being variable, or provided with a pair of transporting rollers that transports a recording material in the transportation path for transporting a recording material with the inclination of the pair of transporting rollers along the axial direction being variable with respect to the transportation surface.

Abstract: A sheet convayance apparatus includes a switchback path in which a sheet is conveyed, paired sheet edge stop rollers arranged along the switchback path, capable of being rotated forwardly or reversely, and a controller for controlling a drive of the paired sheet edge stop rollers so that a collision of and edge of the sheet with the paired sheet edge stop rollers and a switching of a conveyance direction of the sheet are performed by a single stop operation of the sheet.

Abstract: In the discharge section to correct the potential of toner image on the intermediate transfer body before the secondary image transfer and to obtain a good secondary transfer image, it is made that the opposite electrode is brought into contact with the back surface of the intermediate transfer body under the stable condition.

Abstract: An image forming apparatus having an image forming unit that forms an image on an image bearing member, and a mainframe that firmly supports and positions the image bearing member and the image forming unit. The main frame has two side walls which are opposed to each other and substantially support the image bearing member and the image forming unit, a bottom wall to which the two side walls are rigidly connected, and a stay which is rigidly connected to the two side walls and is spaced away from the bottom wall. The bottom wall and the stay have a box type structure with an inner hollow room.

Abstract: A transmission mechanism for transmitting rotation of a driving source in a main body to an object mounted on the main body for receiving the rotation, the transmission mechanism comprising a plurality of couplings provided at different positions along an axial direction of a rotating axis; wherein each of the couplings comprises, a male coupling member having a plurality of protrusions provided at an identical internal on an outer circumferential surface of the rotating axis; and a female coupling member having a plurality of protrusions for engaging with the male coupling's protrusions.

Abstract: An image forming apparatus comprises, an image forming unit that forms an image on an image bearing member, and a mainframe that firmly supports and positions the image bearing member and the image forming unit, the main frame comprises two side walls which are opposed each other and substantially support the image bearing member and the image forming unit, a bottom wall to which the two side walls are rigidly connected, and at least one stay which is rigidly connected to the two side walls in the manner of leaving space from the bottom wall, wherein each of the bottom wall and the at least one stay has a box type structure having an inner hollow room.

Abstract: A transmission mechanism for transmitting rotation of a driving source in a main body to an object mounted on the main body for receiving the rotation, the transmission mechanism comprising a plurality of couplings provided at different positions along an axial direction of a rotating axis; wherein each of the couplings comprises, a male coupling member having a plurality of convex elements provided at an identical internal on an outer circumferential surface of the rotating axis; and a female coupling member having a plurality of concave elements for engaging with the convex elements.

Abstract: An image forming apparatus having a rotational body. The apparatus includes: the rotating body such as a photoreceptor drum; a driver for driving the rotating body; the first member, provided in a driving transmission path of the driving force, for transmitting the driving force from the driving source to the rotating body, and for elastically deforming itself so as to control a natural frequency value of a driving system including the rotating body and driving source; and the second member, provided in the driving transmission path of the driving force, for controlling damping characteristics of the driving system.