A sheet housing apparatus including a housing unit, which houses a sheet to be discharged from a discharging opening of a printer, and a pair of housing-side feet disposed on both sides, in a width direction, of the sheet housing apparatus. The sheet housing apparatus can be combined with the printer. The printer includes a pair of body-side feet disposed on both sides, in the width direction, of the printer. In a state in which the sheet housing apparatus is combined with the printer, the body-side feet and the housing-side feet are arranged not to overlap with each other in the width direction.

There is provided printing equipment that enhances the overprinting position accuracy in overprinting and a printing method for the printing equipment. In the printing method, a paper meandering profile acquisition part acquires a meandering profile of paper from a result of detection by a paper deviation detection sensor. A paper speed profile acquisition part acquires a paper speed profile from a result of detection by a paper conveyance speed detection sensor. A paper feed error calculator calculates a paper feed error on the basis of the meandering profile and paper speed profile. A paper feed error corrector corrects the image formation timing on the basis of a result of calculation by the paper feed error calculator.

In an image forming apparatus, when a first sheet and a second sheet are subjected to printing and the second sheet is being conveyed at a particular timing after a sheet sensor detected passage of a trailing end of the first sheet, and when a sheet interval between the first sheet and the second sheet is equal to or greater than a particular threshold interval, a controller positions first and second developing rollers to first and second separated positions, respectively, after developing of images to be transferred onto the first sheet has been completed, positions the developing rollers to be used for printing on the second sheet to respective contact positions, and starts developing images to be transferred on the second sheet. The controller is further configured to perform a color printing using both the first and second developing rollers, and a monochromatic printing using only the second developing roller.

After outputting a first start signal for causing an image forming unit to start formation of an image for a first side of an i-th sheet, a controller causes a feeding member to start feeding of the i-th sheet, and determines whether or not the i-th sheet has already been detected by a detector. In a case where the i-th sheet has been detected before a first predetermined time has elapsed, the controller outputs a second start signal for causing the image forming unit to start formation of an image for second side of an (i1)th sheet. In a case where the i-th sheet has not been detected before the first predetermined time has elapsed, the controller outputs the second start signal after the i-th sheet is detected.

According to one embodiment, an image forming apparatus includes: a registration roller; a motor configured to drive the registration roller; and a controller configured to control the motor. The registration roller is disposed at a first position on a conveyance path of paper on which an image is to be formed, and sends out the paper toward a second position on the conveyance path. The second position is downstream from the first position on the conveyance path and is an image transfer position on the paper. The controller controls the motor by using both speed control and position control when the leading end of the paper is at a position from the first position to the second position, and controls the motor by using only the speed control when the leading end of the paper reaches the second position.

According to one embodiment, an image forming apparatus includes: a registration roller; a motor configured to drive the registration roller; and a controller configured to control the motor. The registration roller is disposed at a first position on a conveyance path of paper on which an image is to be formed, and sends out the paper toward a second position on the conveyance path. The second position is downstream from the first position on the conveyance path and is an image transfer position on the paper. The controller controls the motor by using both speed control and position control when the leading end of the paper is at a position from the first position to the second position, and controls the motor by using only the speed control when the leading end of the paper reaches the second position.

An image forming apparatus includes the following, a pair of first conveying rollers, a pair of second conveying rollers, a driver which rotates and drives the second conveying rollers by a command value; and a controller which is able to control the driver to perform constant speed control to rotate the pair of second conveying rollers at a constant speed and to perform constant torque control to rotate the pair of second conveying rollers at a constant torque. When the constant torque control is performed, the controller starts the constant torque control with a predetermined initial torque. Based on sheet interval torque detected in a sheet interval term in which the pair of second conveying rollers do not sandwich and convey a sheet after the first sheet reaches the pair of second conveying rollers, the controller corrects the initial torque and calculates a command value for the next sheet.

An image forming device includes a sheet feeding device, an image forming part, a fixing device, a conveyance path, a first sensor and a second sensor. The first sensor is disposed on the conveyance path on a downstream side of the fixing device in the conveyance direction and detects the sheet passed along the conveyance path. The second sensor is disposed on the conveyance path on an upstream side of the fixing device in a conveyance direction and detects the sheet passed along the conveyance path. The fixing device stops a driving of a heating source and stops a rotation of a fixing belt when the first sensor does not detect the sheet passing properly. The fixing device stops the driving of the heating source and stops the rotation of the fixing belt after a predetermined period when the second sensor do not detect the sheet passing properly.

Provided is an image forming apparatus including an intermediate transfer body; a secondary transfer section; a conveyance section; a first detection section; a second detection section that is arranged downstream of the first detection section in a conveyance direction of a medium; and a control section that performs control for changing a conveyance speed of the medium by the conveyance section to a first speed based on timing of detection of the medium by the first detection section and a position of the image on the intermediate transfer body at that time point and changing the conveyance speed of the medium by the conveyance section to a second speed equal to the traveling speed of the intermediate transfer body based on timing of detection of the medium by the second detection section and the position of the image on the intermediate transfer body at that time point.

The number of circulatable sheets and the conveying speed of a sheet are decided by referring to a storage unit which stores the number of circulatable sheets and the conveying speed of a sheet in correspondence with the type and size of a sheet, and the resolution of an image to be printed. It is determined whether the conveying speed of the feed surface of a sheet to be fed next to the printing unit and that of a feed surface to be refed next to the printing unit coincide with each other. It is determined whether the conveying speed of the feed surface of the sheet to be fed next to the printing unit and that of the feed surface or the refeed surface of a sheet immediately previously fed to the printing unit differ from each other.