Alignment apparatuses include a frame and contact elements connected to the frame. The contact elements contact items that are to be transported in a processing direction relative to the frame. The contact elements are in permeant fixed positions relative to the frame, and do not move relative to the frame. Adjustable mounts are connected to the frame and move the frame in the processing direction and in a perpendicular cross-processing direction. A controller is electrically connected to the adjustable mounts, and the controller is adapted to control the adjustable mounts to simultaneously move the frame and all the contact elements in the cross-processing direction and the processing direction while rotating the frame. Methods laterally shift imaging on sheets that have had rotational correction performed by such alignment apparatuses.

An image forming apparatus forms a plurality of images of different colors on an intermediate transfer belt by a plurality of image forming portions. The image forming apparatus detects a color misregistration amount of the image formed on the intermediate transfer belt and performs image formation using a correction value based on the color misregistration amount. If an elapsed time from previous image formation is less than a predetermined time, the image forming apparatus predicts the correction value using the previous correction value and the temperature at that time and performs color misregistration correction. If the elapsed time from the previous image formation is a predetermined time or longer, the image forming apparatus predicts the correction value using the correction value and the temperature at the time when the elapsed time becomes a predetermined time or longer and performs the color misregistration correction.

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.

A characteristic detector includes two electrodes facing each other to form a passage through which a medium passes, a cover disposed between the two electrodes, a current generator to supply a current between the two electrodes, a capacitance gauge to measure a capacitance generated between the two electrodes, and circuitry. The two electrodes have a shape or an arrangement in which at least two points on a leading end of the medium enter the passage with a time lag. The cover covers one of the two electrodes in connection with a size of the medium. The capacitance gauge detects the size of the medium based on the measured capacitance. The circuitry calculates a characteristic of the medium based on the capacitance measured by the capacitance gauge and the size of the medium detected by the capacitance gauge.

A digital printing system having a linear printhead includes corrections for in-track position errors. A data processing system implements a method for determining an in-track position function which includes printing a test target including a plurality of alignment marks, automatically analyzing a captured image of the printed test target to determine a measured in-track position for each of the alignment marks, comparing the measured in-track positions for the alignment marks to reference in-track positions to determine measured in-track position errors, and determining an in-track position correction function responsive to the measured in-track position errors. The in-track position correction function specifies in-track position corrections to be applied as a function of cross-track position. A corrected digital image is determined by resampling an input digital image responsive to the in-track position correction function.

Alignment apparatuses include a frame and contact elements connected to the frame. The contact elements contact items that are to be transported in a processing direction relative to the frame. The contact elements are in permeant fixed positions relative to the frame, and do not move relative to the frame. Adjustable mounts are connected to the frame and move the frame in the processing direction and in a perpendicular cross-processing direction. A controller is electrically connected to the adjustable mounts, and the controller is adapted to control the adjustable mounts to simultaneously move the frame and all the contact elements in the cross-processing direction and the processing direction while rotating the frame. Methods laterally shift imaging on sheets that have had rotational correction performed by such alignment apparatuses.

A sheet type determining device including a guide that guides a sheet along a sheet conveyance path to a destination. The sheet conveyance path is between a first guide surface and a second guide surface facing each other across an interval. The sheet type determining device further includes a determiner that determines a sheet type when the sheet is in the sheet conveyance path, without having contact with the sheet in conveyance, and one or more regulators that regulate a displacement range of the sheet at a determining position, the displacement range being in a direction of the interval of the first and the second guide surfaces. Each of the regulators is a member that protrudes in an arc shape from the first or the second guide surface toward the guide surface opposite, and is spaced from the guide surface or another one of the regulators opposite.

An image forming apparatus includes an image carrier, a transfer member, a registration roller pair, and a conveyance guide which includes a first conveyance guide and a second conveyance guide. The second conveyance guide has a main body portion and a shaft member. The shaft member is held by a shaft holding portion of the main body portion so as to be reciprocatable between a first position which is a most downstream-side position and a second position on an upstream side of the first position. When a first recording medium is conveyed, the shaft member is arranged at the first position such that a distance between the shaft member and the first conveyance guide is a predetermined distance. When a second recording medium is conveyed, the shaft member is arranged at the second position such that the distance between the shaft member and the first conveyance guide is increased.

A sheet conveyance device includes a conveyance roller pair to convey a sheet, a skew correction roller pair to correct a skew of the sheet in a state in which the skew correction roller pair is being stopped, first and second conveyance guides, and a protrusion. The first conveyance guide includes a bend contact portion to come into contact with a portion forming a bend on the first surface of the sheet. The second conveyance guides the sheet. The protrusion is disposed between the skew correction roller pair and the bend contact portion to come into contact with the first surface of the sheet. The protrusion protrudes toward the second conveyance guide from the first conveyance guide in a manner as to intersect with a straight line connecting two nip portions and the bend contact portion in a cross section perpendicular to a width direction.