Abstract: A sheet transporting device includes: a pair of transporting rolls provided to a sheet transport path; a separating component configured to move one of transporting rolls that form the pair of transporting rolls to an open position where the one of the transporting rolls is spaced apart from an other of the transporting rolls; and a switching component having a switching function of switching a position of the pair of transporting rolls between a nipping position and an unnipping position, the switching component being configured to resume the switching function when the pair of transporting rolls once moved to the open position by the separating component is returned to a normal operating position.

Abstract: A sheet transport device includes a pair of movable transport rollers capable of transporting a sheet while holding the sheet and capable of moving in an axial direction crossing a transportation direction; pairs of first transport rollers disposed upstream from the pair of movable transport rollers in the transportation direction while being spaced apart from each other to transport the sheet while holding the sheet; and pairs of transport guides disposed to define sheet transport spaces between the pair of movable transport rollers and the pairs of first transport rollers and between the pairs of first transport rollers. When the pair of movable transport rollers is to be moved in the axial direction, at least one of the pairs of first transport rollers is displaced in the axial direction while holding a portion of the transported sheet.

Abstract: A sheet transporting device includes: plural pairs of transporting rolls that are arranged adjacent to one another in a direction of transport of a sheet; and a component configured to switch individual positions of the plural pairs of transporting rolls between a nipping position and an unnipping position, the component being a single switching component capable of switching a state of nipping by the plural pairs of transporting rolls between a state where all of the plural pairs of transporting rolls are in the nipping position, a state where some of the plural pairs of transporting rolls are in the nipping position while remaining ones of the plural pairs of transporting rolls are in the unnipping position, and a state where all of the plural pairs of transporting rolls are in the unnipping position.

Abstract: A sheet transport device includes a pair of movable transport rollers capable of transporting a sheet while holding the sheet and capable of moving in an axial direction crossing a transportation direction; pairs of first transport rollers disposed upstream from the pair of movable transport rollers in the transportation direction while being spaced apart from each other to transport the sheet while holding the sheet; and pairs of transport guides disposed to define sheet transport spaces between the pair of movable transport rollers and the pairs of first transport rollers and between the pairs of first transport rollers. When the pair of movable transport rollers is to be moved in the axial direction, first transport rollers in at least one of the pairs of first transport rollers are separated not to hold at least part of a portion of the transported sheet located upstream from the pair of movable transport rollers.

Abstract: A sheet transport device includes a pair of movable transport rollers capable of transporting a sheet while holding the sheet and capable of moving in an axial direction crossing a transportation direction; pairs of first transport rollers disposed at a distance from each other upstream from the pair of movable transport rollers in the transportation direction to transport the sheet while holding the sheet; and pairs of first transport guides disposed to define sheet transport spaces between the pair of movable transport rollers and the pairs of first transport rollers and between the pairs of first transport rollers. When the pair of movable transport rollers is moved in the axial direction, at least one of the pairs of first transport rollers is displaced in a direction to widen the transport space.

Abstract: A medium transport device includes a positional corrector configured to transport a medium and correct a position of the medium in a width direction of the medium by moving the medium in the width direction, and an inclination corrector configured to transport the medium and correct an inclination of the medium relative to a transport direction of the medium on an upstream side of the positional corrector in the transport direction, the inclination corrector being disposed at a position where the medium is transported in a flat posture.

Abstract: A sheet transport device includes a pair of movable transport rollers capable of transporting a sheet while holding the sheet and moving in an axial direction crossing a transportation direction; pairs of first transport rollers upstream from the pair of movable transport rollers in the transportation direction while being spaced apart from each other to transport the sheet while holding the sheet; and pairs of transport guides to define sheet transport spaces between the pair of movable transport rollers and the pairs of first transport rollers and between the pairs of first transport rollers. When the pair of movable transport rollers is to be moved in the axial direction, at least one pair of first transport rollers transports the sheet while bending the sheet in the transport space by producing a difference in transport rate within a portion of a section upstream from the pair of movable transport rollers.

Abstract: An image forming apparatus includes a supplying unit that supplies a continuous recording material, an image forming unit that forms an image on the recording material supplied from the supplying unit, a fixing unit that fixes the image formed on the recording material by the image forming unit, a collecting unit that collects the recording material having passed through the fixing unit, a detecting device that detects a change in tension of the recording material running between the image forming unit and the fixing unit, and a tension adjusting device that adjusts the tension acting on the recording material such that the change in the tension of the recording material falls within a permissible range if the change in the tension of the recording material that is detected by the detecting device exceeds the predetermined permissible range.

Abstract: A drive mechanism includes a first transmission mechanism that transmits a driving force of a drive unit to a first rotary member to rotate the first rotary member; a second transmission mechanism including a first drive path along which the second transmission mechanism transmits the driving force to a second rotary member through a first gear train to rotate the second rotary member, and a second drive path along which the second transmission mechanism transmits the driving force to the second rotary member through a second gear train to rotate the second rotary member, the second gear train having a gear ratio that differs from a gear ratio of the first gear train; and a switching mechanism that is operated by the driving force and switches the second transmission mechanism between the first drive path and the second drive path.

Abstract: An image forming apparatus includes an image holding member on which an image is held, and a transfer unit transferring the held image to a recording material, wherein the transfer unit includes, a transfer roll disposed to be opposite to the image holding member, forming a transfer electric field, and transferring the image to the recording material, a drive unit applying driving force to the transfer roll, a torque limiting machanics limiting an upper limit of torque which acts on the transfer roll, and an inertia member provided to increase an amount of inertia with respect to the transfer roll and moving the transfer roll with inertia in a direction in which a speed difference between the image holding member and the transfer roll is decreased when the upper limit of torque acts on the transfer roll.

Abstract: An image forming apparatus includes: a belt member stretched across at least two rollers; a protrusion disposed, such that it protrudes along the traveling direction of the belt member, on an inner surface of one edge side of the belt member; an engagement portion that is formed in an end portion of the rollers and with which the protrusion is engageable; and an image carrier that retains a toner image transferred to a recording medium conveyed by the belt member or the surface of the belt member. The end portion at the opposite side, in the width direction of the belt member, of one roller of the rollers is shifted in the direction where it separates from the image carrier and axially supported.

Abstract: An image forming apparatus including: a conveyance unit including a belt member stretched across at least a drive roller and a driven roller and conveys a recording medium and a casing that axially supports the drive roller and the driven roller; a body frame disposed with an image carrier for transferring an image to the recording medium; and a cover to which the conveyance unit is attached, is pivotably attached to the body frame, and opens/closes off the image carrier. A first regulating portion against which an annular member placed on a shaft portion of the drive roller abuts when the cover pivots toward the body frame to close off the image carrier and a second regulating portion with which an engagement portion formed in the casing in a direction orthogonal to the axial direction of the drive roller engages are formed on the body frame.

Abstract: An image forming apparatus includes a photoreceptor, a driving unit which rotation-drives the photoreceptor, an exposure unit which forms a latent image by performing image exposure to the photoreceptor, a plurality of development units which develop a plurality of latent images sequentially formed on the photoreceptor with different color toners respectively, a belt-like intermediate transfer member onto which respective color toner images sequentially developed on the photoreceptor are primarily transferred to be superimposed on each other, at least one load unit which comes in contact with or is separated from the belt-like intermediate transfer member to change a load on the belt-like intermediate transfer member, and a speed control unit which increases/decreases a driving speed of the photoreceptor at a specified timing. Preferably, the belt-like intermediate transfer member is an elastic belt.

Abstract: An image forming apparatus which includes an image carrier holding toner images of plural colors, and a transfer portion that transfers the toner images of plural of colors held on the image carrier onto a recording medium, wherein the image carrier is made of an elastic material, has a pattern image forming unit repeatedly forming a pattern image for color misregistration detection on the image carrier at a constant interval so as to set the pattern images within a length range of the recording medium, wherein one of the pattern images includes a first toner image group in which plural toner images of a first color is formed at a first interval, and a second toner image group in which plural toner images of a second color is formed at a second interval.

Abstract: An image forming apparatus includes: a belt member stretched across at least two rollers; a protrusion disposed, such that it protrudes along the traveling direction of the belt member, on an inner surface of one edge side of the belt member; an engagement portion that is formed in an end portion of the rollers and with which the protrusion is engageable; and an image carrier that retains a toner image transferred to a recording medium conveyed by the belt member or the surface of the belt member. The end portion at the opposite side, in the width direction of the belt member, of one roller of the rollers is shifted in the direction where it separates from the image carrier and axially supported.

Abstract: An image forming apparatus including: a conveyance unit including a belt member stretched across at least a drive roller and a driven roller and conveys a recording medium and a casing that axially supports the drive roller and the driven roller; a body frame disposed with an image carrier for transferring an image to the recording medium; and a cover to which the conveyance unit is attached, is pivotably attached to the body frame, and opens/closes off the image carrier. A first regulating portion against which an annular member placed on a shaft portion of the drive roller abuts when the cover pivots toward the body frame to close off the image carrier and a second regulating portion with which an engagement portion formed in the casing in a direction orthogonal to the axial direction of the drive roller engages are formed on the body frame.

Abstract: An image forming apparatus which includes an image carrier holding toner images of plural colors, and a transfer portion that transfers the toner images of plural of colors held on the image carrier onto a recording medium, wherein the image carrier is rotatablly disposed toward the image carrier and has elasticity in a rotating direction toward the image carrier, has a pattern image forming unit repeatedly forming a pattern image for color misregistration detection on the image carrier at a constant interval so as to set the pattern images within a length range of the recording medium, wherein one of the pattern images includes a first toner image group in which plural toner images of a first color is formed at a first interval, and a second toner image group in which plural toner images of a second color is formed at a second interval.

Abstract: An image forming apparatus includes a photoreceptor, a driving unit which rotation-drives the photoreceptor, an exposure unit which forms a latent image by performing image exposure to the photoreceptor, a plurality of development units which develop a plurality of latent images sequentially formed on the photoreceptor with different color toners respectively, a belt-like intermediate transfer member onto which respective color toner images sequentially developed on the photoreceptor are primarily transferred to be superimposed on each other, at least one load unit which comes in contact with or is separated from the belt-like intermediate transfer member to change a load on the belt-like intermediate transfer member, and a speed control unit which increases/decreases a driving speed of the photoreceptor at a specified timing. Preferably, the belt-like intermediate transfer member is an elastic belt.

Abstract: In an image forming apparatus using an electro-photographic technique and having an endless belt-shaped photosensitive body for transferring images, a mechanism is provided to maintain the photosensitive body at a constant transfer speed over its entire length irrespective of the effects of various devices in contact with it. A driving roller drives the photosensitive body by contacting its rear surface. One or more guide rollers are also in contact with the rear surface of the photosensitive body for guiding it in conjunction with the driving roller. A transmission such as a belt and pulley or gear mechanism transmits driving force from the driving roller to one or more of the guide rollers. When at least two guide rollers are provided, one is disposed between and above the driving roller and the second guide roller. The driving roller and the second guide roller are so disposed that the portion of the photosensitive body between them lies in a horizontal plane.

Abstract: In an image forming apparatus using an electro-photographic technique and having an endless belt-shaped photosensitive body for transferring images, a mechanism is provided to maintain the photosensitive body at a constant transfer speed over its entire length irrespective of the effects of various devices in contact with it. A driving roller drives the photosensitive body by contacting its rear surface. One or more guide rollers are also in contact with the rear surface of the photosensitive body for guiding it in conjunction with the driving roller. A transmission such as a belt and pulley or gear mechanism transmits driving force from the driving roller to one or more of the guide rollers. When at least two guide rollers are provided, one is disposed between and above the driving roller and the second guide roller. The driving roller and the second guide roller are so disposed that the portion of the photosensitive body between them lies in a horizontal plane.