Abstract: A sheet feeding device includes a feeding roller pair, a first guide, a door including a second guide and rotatable between a first direction and a second direction opposite to the first direction through first to third positions, a damping mechanism, and an engaging portion including an elastic member. A first resisting force is set so that moment acting around a shaft by a self-weight of the door is larger than the first resisting force of the damping mechanism when the door is positioned between the second position and the third position. A resultant force of the first resisting force of the damping mechanism and a second resisting force of the elastic portion is set so that the moment acting around the shaft by the self-weight of the door is larger than the resultant force when the door is positioned between the second position and the third position.

Abstract: A sheet feeding device includes a feeding roller pair, a first guide, a door including a second guide and rotatable between a first direction and a second direction opposite to the first direction through first to third positions, a damping mechanism, and an engaging portion including an elastic member. A first resisting force is set so that moment acting around a shaft by a self-weight of the door is larger than the first resisting force of the damping mechanism when the door is positioned between the second position and the third position. A resultant force of the first resisting force of the damping mechanism and a second resisting force of the elastic portion is set so that the moment acting around the shaft by the self-weight of the door is larger than the resultant force when the door is positioned between the second position and the third position.

Abstract: An image reading apparatus includes an image reading sensor, a transparent plate, a guiding member, a first roller pair, and a second roller pair provided upstream of the first roller pair with respect to a sheet feeding direction. The first roller pair and the second roller pair are disposed so as to nip a sheet in each of nips of the first roller pair and the second roller pair when a leading end of the sheet enters between the guiding member and the transparent plate.

Abstract: An image forming apparatus includes an image forming unit to form an image on a sheet, a conveyance unit to convey the sheet having the image formed thereon to a conveyance path and a reading unit to read a test image of a sheet conveyed to the conveyance path. In addition, a controller determines an adjustment value for adjusting a geometric characteristic of an image to be formed by the image forming unit based on a reading result of the reading unit, controls the image forming unit to form the test image, controls the reading unit to read the sheet having the test image formed thereon, and determines an adjustment value for adjusting a geometric characteristic of an image to be formed by the image forming unit based on a reading result of the reading unit.

Abstract: An image reading apparatus includes an image reading sensor, a transparent plate, a guiding member, a first roller pair, and a second roller pair provided upstream of the first roller pair with respect to a sheet feeding direction. The first roller pair and the second roller pair are disposed so as to nip a sheet in each of nips of the first roller pair and the second roller pair when a leading end of the sheet enters between the guiding member and the transparent plate.

Abstract: An image forming apparatus includes: an image forming unit configured to form an image on a sheet; a conveyance unit configured to convey the sheet having the image formed thereon along a conveyance path; a reading unit configured to read the image on the sheet conveyed to the conveyance path; and a controller configured to: receive a user-designated number of sheets as a condition for a timing at which the image forming unit forms a mark during a period in which a print job for forming a plurality of images on a plurality of sheets is being executed; control, when the print job is executed, the image forming unit to form the mark after the images are formed on sheets of a predetermined number smaller than a threshold number of sheets in a case in which the user-designated number of sheets is larger than the threshold number of sheets.

Abstract: A measuring device includes a first roller pair, a colorimetric unit, a second roller pair, a third roller pair, a motor, and a torque limiter. The third roller pair is driven at a first speed before a trailing end of the sheet with respect to a sheet feeding direction passes through the first roller pair and is driven at a second speed higher than the first speed after the trailing end of the sheet passes through the first roller pair. The first speed is set so as to be equal to the peripheral speed of the first roller pair. The second speed is set so as to be equal to a peripheral speed of the second roller pair in a state in which a slip of the torque limiter is not caused.

Abstract: An image reading apparatus connectable to an image forming apparatus includes a feeding roller pair configured to nip and feed a sheet discharged from the image forming apparatus, a contact image sensor configured to read an image on a first surface of the sheet fed by the feeding roller pair, a light-transmissive plate provided opposed to the contact image sensor and having a light-transmission property, a first roller opposing the light-transmissive plate with a gap therebetween on a side opposite from the contact image sensor with respect to the light-transmissive plat, and a second roller positioned upstream of the first roller with respect to a sheet feeding direction and opposing the light-transmissive plate with a gap therebetween on the same side as the first roller.

Abstract: An image forming apparatus includes: an image forming unit configured to form an image on a sheet; a conveyance unit configured to convey the sheet having the image formed thereon to a conveyance path; a reading unit configured to read a test image of a sheet conveyed to the conveyance path; and a controller configured to: determine an adjustment value for adjusting a geometric characteristic of an image to be formed by the image forming unit based on a reading result of the reading unit; control the image forming unit to form the test image; control the reading unit to read the sheet having the test image formed thereon; determine an adjustment value for adjusting a geometric characteristic of an image to be formed by the image forming unit based on a reading result of the reading unit.

Abstract: An image forming apparatus includes: an image forming unit configured to form an image on a sheet; a conveyance unit configured to convey the sheet having the image formed thereon along a conveyance path; a reading unit configured to read the image on the sheet conveyed to the conveyance path; and a controller configured to: receive a user-designated number of sheets as a condition for a timing at which the image forming unit forms a mark during a period in which a print job for forming a plurality of images on a plurality of sheets is being executed; control, when the print job is executed, the image forming unit to form the mark after the images are formed on sheets of a predetermined number smaller than a threshold number of sheets in a case in which the user-designated number of sheets is larger than the threshold number of sheets.

Abstract: A sheet conveyance apparatus includes a first conveyor, a second conveyor provided downstream of the first conveyor, a first motor configured to drive the first conveyor, a second motor configured to drive the second conveyor, a speed determining unit configured to determine a rotation speed of a rotor of the second motor, a command determining unit configured to determine a command speed representing a target speed of the rotor of the second motor, and a controller configured to control a drive current flowing through a winding of the second motor so that a deviation between the command speed determined by the command determining unit and the rotation speed determined by the speed determining unit is decreased. The command determining unit determines the command speed based on a value corresponding to a rotation speed of a rotor of the first motor.

Abstract: An image reading apparatus connectable to an image forming apparatus includes a feeding roller pair configured to nip and feed a sheet discharged from the image forming apparatus, a contact image sensor configured to read an image on a first surface of the sheet fed by the feeding roller pair, a light-transmissive plate provided opposed to the contact image sensor and having a light-transmission property, a first roller opposing the light-transmissive plate with a gap therebetween on a side opposite from the contact image sensor with respect to the light-transmissive plat, and a second roller positioned upstream of the first roller with respect to a sheet feeding direction and opposing the light-transmissive plate with a gap therebetween on the same side as the first roller.

Abstract: An image reading apparatus includes an image reading sensor, a transparent plate, a guiding member, a first roller pair, and a second roller pair provided upstream of the first roller pair with respect to a sheet feeding direction. The first roller pair and the second roller pair are disposed so as to nip a sheet in each of nips of the first roller pair and the second roller pair when a leading end of the sheet enters between the guiding member and the transparent plate.

Abstract: A sheet feeding device includes a feeding roller pair, a first guide, a door including a second guide and rotatable between a first direction and a second direction opposite to the first direction through first to third positions, a damping mechanism, and an engaging portion including an elastic member. A first resisting force is set so that moment acting around a shaft by a self-weight of the door is larger than the first resisting force of the damping mechanism when the door is positioned between the second position and the third position. A resultant force of the first resisting force of the damping mechanism and a second resisting force of the elastic portion is set so that the moment acting around the shaft by the self-weight of the door is larger than the resultant force when the door is positioned between the second position and the third position.

Abstract: A measuring device includes a first roller pair, a colorimetric unit, a second roller pair, a third roller pair, a motor, and a torque limiter. The third roller pair is driven at a first speed before a trailing end of the sheet with respect to a sheet feeding direction passes through the first roller pair and is driven at a second speed higher than the first speed after the trailing end of the sheet passes through the first roller pair. The first speed is set so as to be equal to the peripheral speed of the first roller pair. The second speed is set so as to be equal to a peripheral speed of the second roller pair in a state in which a slip of the torque limiter is not caused.

Abstract: A sheet conveyance apparatus includes: a first conveyor; a second conveyor provided on downstream of the first conveyor; a first motor configured to drive the first conveyor; a second motor configured to drive the second conveyor; a speed determining unit configured to determine a rotation speed of a rotor of the second motor; a command determining unit configured to determine a command speed representing a target speed of the rotor of the second motor; and a controller configured to control a drive current flowing through a winding of the second motor so that a deviation between the command speed determined by the command determining unit and the rotation speed determined by the speed determining unit is decreased. The command determining unit determines the command speed based on a value corresponding to a rotation speed of a rotor of the first motor.

Abstract: A particle adhesion preventing member used for an image forming apparatus that forms an image using charged toner, and configured to prevent adhesion of the charged toner, includes a conductive member, and an insulating member that is attached to the conductive member, including a porous member made of an ethylene propylene diene ternary copolymer having a density of 0.01 g/cm3 or more and 0.2 g/cm3 or less or silicon having a density of 0.01 g/cm3 or more and 0.3 g/cm3 or less, and being negatively charged with negatively charged particles adhering onto a surface thereof.

Abstract: A particle adhesion preventing member used for an image forming apparatus that forms an image using charged toner, and configured to prevent adhesion of the charged toner, includes a conductive member, and an insulating member that is attached to the conductive member, including a porous member made of an ethylene propylene diene ternary copolymer having a density of 0.01 g/cm3 or more and 0.2 g/cm3 or less or silicon having a density of 0.01 g/cm3 or more and 0.3 g/cm3 or less, and being negatively charged with negatively charged particles adhering onto a surface thereof.