Abstract: A rotation shaft coupling structure includes a roller drive shaft including a recessed portion having an internal thread; a rotation roller including a coupling member housing the recessed portion of the roller drive shaft; and a coupling shaft extending through the rotation roller in the axial direction. The coupling shaft includes a threaded portion at a first end portion thereof, the threaded portion mating with the internal thread of the recessed portion, and the coupling shaft couples the roller drive shaft and the rotation roller to each other. The first end portion of the coupling shaft in the axial direction is joined to the roller drive shaft and the rotation roller in the coupling member of the rotation roller, and a second end portion of the coupling shaft in the axial direction is a free end that allows the coupling shaft to extend and contract in the axial direction.

Abstract: A drive includes a driving shaft that includes a distal end portion having a screw hole at a distal end and being inserted into a hollow portion from a first end of a driving roller in a rotation-axis direction, and that transmits a rotational driving force to the driving roller through a fit portion; a spring washer arranged at a second end of the driving roller opposite to the first end in the rotation-axis direction; and a screw rod that has an external thread which is screwed into the screw hole, that is inserted into the spring washer and inserted into the hollow portion from the second end, and that pinches the driving roller between the screw rod and the fit portion of the driving shaft in the rotation-axis direction through the spring washer when the external thread is screwed into the screw hole.

Abstract: A drive includes a driving shaft that includes a distal end portion having a screw hole at a distal end and being inserted into a hollow portion from a first end of a driving roller in a rotation-axis direction, and that transmits a rotational driving force to the driving roller through a fit portion; a spring washer arranged at a second end of the driving roller opposite to the first end in the rotation-axis direction; and a screw rod that has an external thread which is screwed into the screw hole, that is inserted into the spring washer and inserted into the hollow portion from the second end, and that pinches the driving roller between the screw rod and the fit portion of the driving shaft in the rotation-axis direction through the spring washer when the external thread is screwed into the screw hole.

Abstract: An image forming apparatus which reduces a color misregistration caused by a variation in speed of a photoconductor or an intermediate transfer medium. The image forming apparatus is constructed to superimpose multiple color images on each other on an intermediate transfer medium by rotating a photoconductor and the intermediate transfer medium and to form a color image. In the image forming apparatus, detection is made as to the phase difference between the timing of forming a latent image on the photoconductor and the rotational speed of the intermediate transfer medium, and the detected phase difference is corrected by increasing or decreasing the rotational speed of the intermediate transfer medium by using a correction signal, while no latent image is being transferred to the intermediate transfer medium. In addition, a transfer misregistration caused by a variation in load acting on the intermediate transfer medium is corrected by adding the transfer misregistration to a correction signal.

Abstract: A drive apparatus is comprised of a driven shift of a rotary photosensitive drum, a drive motor and a gear mechanism for rotatably driving the driven shaft, and a flywheel rotated around a wheel rotary shaft, for stabilizing the rotations of the driven shaft. A pulley having a large diameter is mounted on a rotary shaft directly coupled to the driven shaft, whereas a pulley having a small diameter is mounted on the wheel rotary shaft. An endless belt is wound on these pulleys, so that drive force is transferred from the rotary shaft to the wheel rotary shaft, and an angular velocity of the flywheel is made higher than that of the driven shaft.

Abstract: A stepping motor having two stator units axially arranged. Each of the stator units includes an inner yoke and an outer yoke having a plurality of pole teeth circumferentially formed at a predetermined pitch around a rotor having magnetic poles. The outer yoke of one of the stator units is asymmetrically arranged so that the pole teeth thereof are shifted from center between the pole teeth of the inner yoke in a specific direction. As a result, a cogging torque is reduced, constant speed rotation is attained and variations in the output torque are eliminated. Variation in the generated torque are also reduced by controlling the drive pulse width, the drive voltage or the drive current during the driving operation in accordance with the number of excitation phases.

Abstract: A recorder motor with an encoder, for forming an image on a record medium in accordance with image information, has the encoder on the outside of the motor case and a plastic dust-proof cover for the encoder mounted on the case. Thus, contamination by dust or ink mist is prevented, and stable and high precision motor rotation is maintained.