Abstract: A sheet conveyance device to convey a sheet which is stored within a sheet storing section, including: a plurality of sheet conveyance rollers, mounted on a sheet storing section, to be parallel to each other with respect to rotating centers, wherein the plurality of the sheet conveyance rollers come into contact with the sheet to convey the sheet toward an exterior of the sheet conveyance device; and a coupling section to couple the plurality of the sheet conveyance rollers and to rotate the plurality of the sheet conveyance rollers, wherein at least one of the plurality of the sheet conveyance rollers represents an irregularly shaped roller, wherein the irregularly shaped roller is coupled to another sheet conveyance roller by the coupling section, and wherein a distance between a rotation center and a peripheral surface of the irregularly shaped roller is inconstant, in a rotational direction of the irregularly shaped roller.

Abstract: An image forming apparatus includes: an image forming section that forms a toner image on a sheet; a fixing section that fixes the toner image on the sheet; a sheet conveyance path that branches into a first sheet conveyance path and a second sheet conveyance path downstream of the fixing section; a blowing section that guides the sheet to the first sheet conveyance path or to the second sheet conveyance path by blowing air to the sheet; and a controller that controls the blowing air of the blowing section.

Abstract: A sheet conveying apparatus is provided with a decurling mechanism to correct a curl formed on a sheet; a pair of guides including a first guide member and a second guide member arranged to oppose to the first guide member, the pair of guides constituting a conveyance passage to guide a sheet discharged from the decurling mechanism toward the downstream side in the sheet conveying direction; and an auxiliary guide arranged to protrude obliquely in the sheet conveying direction from the side of the first guide member toward the second guide member to a predetermined position in the conveyance passage.

Abstract: A decurl device which corrects a curl of a sheet includes: a soft roller having a surface layer which is deformed by receiving a contact force; a hard roller which contacts the soft roller and deforms the surface layer of the soft roller; a driving section which drives independently each of the soft roller and the hard roller; and a control section which controls the driving section independently to drive the soft roller with a first line speed of a peripheral surface of the soft roller and drive the hard roller with a second line speed of a peripheral surface of the hard roller.

Abstract: An image forming apparatus having: an image forming portion to form an image on a sheet; a fixing device to fix the image to the sheet by heating; a conveying path switching member to switch a conveying direction of the sheet, which is provided on downstream of the fixing device in a sheet conveying direction; a first conveying path which has a first curved portion and is provided on downstream of the conveying path switching member; a second conveying path which has a second curved portion and is provided on downstream of the conveying path switching member; a curl applying member which is provided on downstream of the fixing device, and on upstream of the first and second curved portions; and a control unit to control driving of the conveying path switching member and of the curl applying member.

Abstract: An image forming apparatus, including: an image forming section for forming a toner image on a transfer sheet; a fixing section for fixing the toner image on the transfer sheet; a sheet ejection section for ejecting the sheet on which the toner image has been fixed; and a sheet guide section, including a first guide member and a second guide member both of which are paired for guiding the sheet from the fixing section to the sheet ejection section; wherein a heat radiation characteristic of the first guide member is greater than that of the second guide member.

Abstract: A power transmission device includes a driving gear having gears over an entire circumferential surface thereof, a follower gear including an intermittent gear having a toothless portion, and a controller for controlling the follower gear to be engaged with or disengaged from the driving gear. Each of the driving gear and the follower gear is a helical gear.

Abstract: Image forming apparatus having a manual feeding tray on which transfer sheet is placed and an image forming device to form images on the transfer sheet fed from the manual feeding tray, wherein the image forming apparatus has a storage section to store the sheet feeding tray with transfer sheet thereon and the manual feeding tray has a supporting member.

Abstract: A fixing device, comprising a heating roller being rotatable and having a rotating circumferential surface to come in contact with a recording medium holding non-fixed developing agent images so as to heat and melt the non-fixed developing agent images and a temperature detecting unit having a temperature detecting element to detect temperature of the rotating circumferential surface and a support member to support the detecting element, wherein the support member is arranged to come in contact with the rotating circumferential surface at a first contact position on the rotating circumferential surface, the temperature detecting element is arranged to come in contact with the rotating circumferential surface at a second contact position which is located upstream of the first contact position in the rotating direction. This structure provides a high quality toner images by controlling fixing temperature based on a precise temperature detection of the heating roller.

Abstract: An image forming apparatus having: an image forming portion to form an image on a sheet; a fixing device to fix the image to the sheet by heating; a conveying path switching member to switch a conveying direction of the sheet, which is provided on downstream of the fixing device in a sheet conveying direction; a first conveying path which has a first curved portion and is provided on downstream of the conveying path switching member; a second conveying path which has a second curved portion and is provided on downstream of the conveying path switching member; a curl applying member which is provided on downstream of the fixing device, and on upstream of the first and second curved portions; and a control unit to control driving of the conveying path switching member and of the curl applying member.

Abstract: A fixing device utilized in an image forming apparatus for fixing an image on a recording sheet comprises a heating member including a heating device, a pressure roller which presses the recording sheet to the heating member, a temperature sensor for detecting the heating member and an entry preventing member provided in an upstream side of the temperature sensor for preventing recording sheet from entering into a place where the temperature sensor is attached.

Abstract: Image forming apparatus having a manual feeding tray on which transfer sheet is placed and an image forming device to form images on the transfer sheet fed from the manual feeding tray, wherein the image forming apparatus has a storage section to store the sheet feeding tray with transfer sheet thereon and the manual feeding tray has a supporting member.

Abstract: An image forming apparatus, including: an image forming section for forming a toner image on a transfer sheet; a fixing section for fixing the toner image on the transfer sheet; a sheet ejection section for ejecting the sheet on which the toner image has been fixed; and a sheet guide section, including a first guide member and a second guide member both of which are paired for guiding the sheet from the fixing section to the sheet ejection section; wherein a heat radiation characteristic of the first guide member is greater than that of the second guide member.

Abstract: A recording medium feed device includes: a recording medium feed tray installable to and removable from a main body of the recording medium feed device; a send-out member to send out a recording medium loaded in the recording medium feed tray, the send-out member being in contact with a top face of the recording medium while applying pressure thereto at a time of installing the recording medium feed tray; and a withdrawing mechanism to withdraw the send-out member from the top face of the recording medium in the recording medium feed tray at a time of removing the recording medium feed tray.

Abstract: A power transmission device includes a driving gear having gears over an entire circumferential surface thereof, a follower gear including an intermittent gear having a toothless portion, and a controller for controlling the follower gear to be engaged with or disengaged from the driving gear. Each of the driving gear and the follower gear is a helical gear.

Abstract: A fixing device, comprising a heating roller being rotatable and having a rotating circumferential surface to come in contact with a recording medium holding non-fixed developing agent images so as to heat and melt the non-fixed developing agent images and a temperature detecting unit having a temperature detecting element to detect temperature of the rotating circumferential surface and a support member to support the detecting element, wherein the support member is arranged to come in contact with the rotating circumferential surface at a first contact position on the rotating circumferential surface, the temperature detecting element is arranged to come in contact with the rotating circumferential surface at a second contact position which is located upstream of the first contact position in the rotating direction. This structure provides a high quality toner images by controlling fixing temperature based on a precise temperature detection of the heating roller.

Abstract: An image forming apparatus includes, a rotatable image carrier, a writing exposure device to write the image and form a latent image in the rotatable image carrier, a developing device to form a toner image, a registration roller to convey a transfer sheet to an image transfer area where the toner image is transferred from the image carrier onto the transfer sheet, and a fixing roller to heat and fix the toner image, wherein when the length of a transfer sheet is longer than the length of the transfer sheet path between the registration roller and the fixing roller, according to the size of the transfer sheet, the controller changes and controls the relative rotating speed of the registration roller to a rotating speed of the fixing roller, and one of a rotating speed of the rotatable image carrier and a writing speed of the image.

Abstract: A sheet feeding device includes: a conveyance path along which a recording sheet is conveyed; a separation roller that separates a recording sheet and conveys it; a registration roller that stops temporarily a recording sheet separated and conveyed by the separation roller and further conveyed along the conveyance path, and conveys the recording sheet again toward the image forming position at the prescribed timing; a detector that is provided in the conveyance path between the separation roller and the registration roller, and detects the recording sheet; a recognizing device that recognizes fluctuation of conveyance timing of the recording sheet based on the results of the detection made by the detector; and a controller that conducts conveyance control for the recording sheet at the upstream side of the registration roller based on the results of the recognition made by the recognizing device.

Abstract: An image forming apparatus comprises, a rotatable image carrier, a writing exposure device to write the image and form a latent image in the rotatable image carrier, a developing device to form a toner image, a registration roller to convey a transfer sheet to an image transfer area where the toner image is transferred from the image carrier onto the transfer sheet, and a fixing roller to heat and fix the toner image, wherein when the length of a transfer sheet is longer than the length of the transfer sheet path between the registration roller and the fixing roller, according to the size of the transfer sheet, the controller changes and controls the relative rotating speed of the registration roller to a rotating speed of the fixing roller, and one of a rotating speed of the rotatable image carrier and a writing speed of the image.

Abstract: An image forming apparatus includes a plurality of sheet feed units each for feeding a sheet, a single pair of registration rollers provided at the upstream side of the image formation site where an image is formed on the sheet with respect to the direction of sheet conveyance, for conveying the sheet in accordance with the timing of forming the image on the sheet, and a plurality pair of loop forming rollers provided in correspondence with the plurality of sheet feed units respectively at the upstream side of the pair of registration rollers with respect to the direction of sheet conveyance. Each of the plurality pair of loop forming rollers is controlled in a manner such that a loop is formed between each of the plurality pair of loop forming rollers and the pair of registration rollers.