Abstract: An image forming apparatus includes a holding body that holds a formed image; a transport unit that transports a recording medium in a state where a tip of the recording medium is grasped by a grasping portion; a transfer cylinder that has a substantially circular cross section, and that includes a concave portion that accommodates the grasping portion in a direction substantially orthogonal to a rotation direction and transfers an image on the holding body to the recording medium transported by the transport unit by interposing the recording medium transported by the transport unit between the transfer cylinder and the holding body; and an imparting portion that imparts a transport load to the recording medium that is transported to a transfer position at which the image on the holding body is transferred to the recording medium.

Abstract: A transfer device includes: an endless transfer belt that circulates and receives an image; one image carrier that carries an image and is in contact with an outer circumferential surface of the transfer belt from above; another image carrier that carries an image and is in contact with the outer circumferential surface of the transfer belt from below; one transfer roller that holds the transfer belt with respect to the one image carrier to transfer the image carried on the one image carrier to the transfer belt, the one transfer roller including one cylindrical roller part; and another transfer roller that holds the transfer belt with respect to the other image carrier to transfer the image carried on the other image carrier to the transfer belt, the other transfer roller including another cylindrical roller part. The one roller part and the other roller part protrude at central portions thereof in the axial direction with respect to ends thereof in the axial direction.

Abstract: A transfer device includes: a transfer cylinder that is rotated, and that includes a cylinder main body having an outer circumferential surface provided with a recess for housing a holding member holding a leading end of a recording medium to convey the recording medium, and a sheet member that is wound around the outer circumferential surface, both ends of which are attached to circumferential ends of the recess, respectively, and that has an inclined surface on a downstream end in a conveying direction of the recording medium; and a transfer member to which a transfer voltage is applied and that transfers a developer image to the recording medium held and conveyed by the holding member, at a transfer position, wherein application of the transfer voltage to the transfer member is started after a tip end of the inclined surface arrives at the transfer position.

Abstract: An image forming apparatus includes: a holding body configured to hold a formed image; a conveyance unit configured to convey a recording medium with a leading end of the recording medium gripped by a gripping portion; and a transfer body including a recessed portion that accommodates the gripping portion and is provided along a direction substantially orthogonal to a rotational direction, configured to sandwich the recording medium conveyed by the conveyance unit between the transfer body and the holding body to transfer an image on the holding body to the recording medium conveyed by the conveyance unit, and including a slope surface provided at a leading end of a portion of an outer circumference not including a portion where the recessed portion is provided, the leading end being on a front end side in the rotational direction, a distance from the slope surface to a rotational center becoming larger toward a downstream side in the rotational direction.

Abstract: Provided is an image forming apparatus including: an annular transfer belt having an outer surface on which an image is transferred; a transferring unit including a transfer cylinder having a transfer area that sandwiches a recording medium with the outer surface of the transfer belt to transfer the image from the outer surface of the transfer belt to the recording medium, and a pair of first rotating bodies disposed on both axial end sides of the transfer cylinder; a pair of circulating members each being wound around the first rotating body and being circulated by rotation of the first rotating bodies; and a holding unit attached to the circulating members, the holding unit configured to hold the recording medium, transport the recording medium with circulation of the circulating members, and pass the recording medium through the transfer area.

Abstract: A rotation device includes a rotator that includes a recessed portion formed on an outer circumferential surface and that rotates in a predetermined rotation direction; a contact unit that comes into contact with a portion of the outer circumferential surface in a range from an upstream end to a downstream end of the recessed portion in the rotation direction at a predetermined engagement depth; and a contact surface that is formed at an upstream end portion in the range in the rotation direction and that comes into contact with the contact unit at a second engagement depth less than a first engagement depth at a portion downstream of the upstream end portion.

Abstract: A transfer member includes: an inner layer; and an outer layer that is adhered to the inner layer and has a hardness lower than a hardness of the inner layer.

Abstract: A transfer device includes a transfer drum that rotates in conjunction with a fixing roller, a transfer belt that transfers an image onto a medium while rotating along with the transfer drum in a state where the medium is nipped between the transfer belt and the transfer drum, a pressing member that is disposed in a space enclosed by the transfer belt, and a switching unit that moves the pressing member and switches between a pressed state in which the transfer belt is pressed against the transfer drum and a separated state in which the transfer belt is separated from the transfer drum.

Abstract: A cylinder member includes: a cylinder body having a cross section and including a dent portion; a sheet member wrapped around the cylinder body and including a metal layer contacting the cylinder body and an outer layer; a first attachment member on a sheet member first end portion and removably attached to the dent portion; a second attachment member on a metal layer end portion protruding from the outer layer in the circumferential direction at a sheet member second end portion, the second attachment member being removably attached to the dent portion; a tension-applying mechanism pulling the second attachment member in a dent portion depth direction to apply tension to the metal layer; a projection on one of the second attachment member and metal layer end portion; and a fitting portion on other one of the second attachment member and the metal layer end portion and fitted to the projection.

Abstract: An image forming apparatus includes: a colorant image former; an image holder configured to hold a colorant image formed by the colorant image former and to be rotationally driven; a transfer member configured to transfer the colorant image onto a recording medium, which is transported from an upstream side, by sandwiching the recording medium between the transfer member and the image holder, and rotationally driving the transfer member to transport the recording medium to a downstream side; and a contact-and-separation mechanism configured to relatively contact or separate the image holder and the transfer member, in which, in response to an abnormality being detected, the image forming apparatus operates in a mode in which the contact-and-separation mechanism relatively separates the image holder and the transfer member, and then rotational driving of the transfer member is stopped after rotational driving of the image holder is stopped.

Abstract: A method for attaching a sheet member to a cylinder body includes: preliminarily fixing a first end portion of the sheet member to a first fixation portion of a cylinder body provided in an apparatus body and having a substantially circular cross section; wrapping the sheet member around the cylinder body by rotating the cylinder body; fixing the first end portion and a second end portion of the sheet member to the first fixation portion and a second fixation portion, respectively; and installing an installation member between the apparatus body and an inner surface of the sheet member before the wrapping of the sheet member around the cylinder body.

Abstract: A drum member includes: a substantially cylindrical drum body having a hollow part extending in an axial direction; a sheet member wound on the drum body; an adjusting mechanism configured to adjust tension in the sheet member, the adjusting mechanism including a moving member that holds an end of the sheet member in a circumferential direction and moves in a depth direction of the hollow part, and a fixing member that fixes the moving member to the drum body; and one or more positioning members that position the moving member such that the moving member does not move in the circumferential direction of the drum body when the moving member is fixed with the fixing member.

Abstract: A jacket includes: a first layer that is on a cylinder body side when the jacket is attached to a rotating cylinder body; and a second layer that is a layer located on a side opposite to the cylinder body with respect to the first layer, has a hardness lower than that of the first layer, and does not exist at a position where at least one of end edges of the cylinder body in a rotation axis direction is located inward of the first layer in the rotation axis direction.

Abstract: An image forming apparatus includes a holding body that holds a formed image; a transport unit that transports a recording medium in a state where a tip of the recording medium is grasped by a grasping portion; a transfer cylinder that has a substantially circular cross section, and that includes a concave portion that accommodates the grasping portion in a direction substantially orthogonal to a rotation direction and transfers an image on the holding body to the recording medium transported by the transport unit by interposing the recording medium transported by the transport unit between the transfer cylinder and the holding body; and an imparting portion that imparts a transport load to the recording medium that is transported to a transfer position at which the image on the holding body is transferred to the recording medium.

Abstract: An image forming apparatus includes: a holding body configured to hold a formed image; a conveyance unit configured to convey a recording medium with a leading end of the recording medium gripped by a gripping portion; and a transfer body including a recessed portion that accommodates the gripping portion and is provided along a direction substantially orthogonal to a rotational direction, configured to sandwich the recording medium conveyed by the conveyance unit between the transfer body and the holding body to transfer an image on the holding body to the recording medium conveyed by the conveyance unit, and including a slope surface provided at a leading end of a portion of an outer circumference not including a portion where the recessed portion is provided, the leading end being on a front end side in the rotational direction, a distance from the slope surface to a rotational center becoming larger toward a downstream side in the rotational direction.

Abstract: A transfer member includes: an inner layer; an outer layer provided on an outer periphery of the inner layer; and a surface layer provided on an outer periphery of the outer layer, both end portions of the surface layer in circumferential directions extending in the circumferential directions from both end portions of the outer layer in the circumferential directions.

Abstract: A transfer device includes: a transfer drum that has a groove-like recess extending in an axial direction in an outer circumferential portion thereof, rotates about an axis thereof, and comes into contact with a medium being transported at a portion thereof on an upstream side of the recess in a rotation direction; a nip member, the nip member and the transfer drum forming therebetween a nip part where the medium is nipped; an application member that applies a voltage to the nip part where the medium is nipped, so that an image is transferred to the medium; and a contact mechanism that causes the nip member to come into contact only with a portion on the upstream side of the recess in the transfer drum in the rotation direction at a transfer-start time when the transfer of the image to the medium starts.

Abstract: A method for attaching a sheet member to a cylinder body includes: preliminarily fixing a first end portion of the sheet member to a first fixation portion of a cylinder body provided in an apparatus body and having a substantially circular cross section; wrapping the sheet member around the cylinder body by rotating the cylinder body; fixing the first end portion and a second end portion of the sheet member to the first fixation portion and a second fixation portion, respectively; and installing an installation member between the apparatus body and an inner surface of the sheet member before the wrapping of the sheet member around the cylinder body.

Abstract: A transfer device includes a transfer drum that rotates in conjunction with a fixing roller, a transfer belt that transfers an image onto a medium while rotating along with the transfer drum in a state where the medium is nipped between the transfer belt and the transfer drum, a pressing member that is disposed in a space enclosed by the transfer belt, and a switching unit that moves the pressing member and switches between a pressed state in which the transfer belt is pressed against the transfer drum and a separated state in which the transfer belt is separated from the transfer drum.

Abstract: An image forming apparatus includes at least one upper image forming unit in which an image holding unit is disposed above a transfer unit in such a manner as to face the transfer unit with a transfer medium, which moves in a predetermined direction, interposed between the image holding unit and the transfer unit and at least one lower image forming unit in which an image holding unit is disposed below a transfer unit in such a manner as to face the transfer unit with the transfer medium interposed between the image holding unit and the transfer unit, the transfer unit of the upper image forming unit and the transfer unit of the lower image forming unit each including a transfer member that extends in a width direction crossing the direction of movement of the transfer medium and that is brought into contact with the transfer medium and a pressing unit that presses the transfer member toward the image holding unit, and the pressing units being set in such a manner that a pressing force that is applied by one