Abstract: A sheet feeding device for feeding a sheet by a vibration wave includes a pair of rotatable rollers each having a rotary shaft orthogonal to the direction of conveyance of the sheet and substantially parallel to the surface of the sheet. The sheet feeding device is designed such that the sheet is nipped by and between the pair of rollers with suitable pressure, thereby eliminating lateral shift and inclination for any extraneous force applied to the sheet.

Abstract: Disclosed is feeding apparatus comprising a first vibration apparatus having projections provided with a predetermined distance therebetween, the first vibration apparatus producing a first travelling vibration wave in response to an electrical signal applied thereto, and a second vibration apparatus having projections located at the positions substantially corresponding to the projections of the first vibration apparatus, the second vibration apparatus producing a second travelling vibration wave proceeding in the same direction as the first travelling vibration wave in response to an electrical signal supplied thereto thereby the sheet inserted between the projections of the first vibration apparatus and the projections of the second vibration apparatus being fed by the first and second travelling vibration waves.

Abstract: An encoder is provided with a light emitting device for emitting irradiating light, a first scale on which a substantially light transmitting portion and light shielding portion are periodically provided, a second scale which is adapted to be displaced relatively to the first scale and on which V-shape groove and light transmission plane portions are periodically provided at a first surface facing the first scale, a light receiving device, arranged to face a second surface of the second scale, for receiving light having passed through the first and second scales and a detecting device for detecting the relative displacement of the two scales based on the output signals from the light receiving device.

Abstract: An improved sheet feeding device of this invention includes a variable pressure applying unit for changing a contact pressure between a sheet and vibration members.

Abstract: There is disclosed a sheet feeding device having at least two vibration members pinching a sheet, which is frictionally driven by the travelling vibration waves generated in the vibration members. The device is further provided with a detector for detecting the state of vibration of the vibration members and generating a signal corresponding to the phase difference between the vibrations. The signal is used for correcting the vibration state of the vibrations members, thus significantly reducing the unevenness in the sheet feeding.

Abstract: There is disclosed a sheet feeding device having a vibration member for generating vibration for feeding a sheet member. The vibration member is in frictional engagement with the sheet member, which is fed by vibration generated in the vibration member. The device further has a member for controlling the amplitude of the vibration of the vibration member according to the feeding speed of the sheet member whereby the sheet can be fed with a desired speed.

Abstract: An optical encoder comprising: an optical scale having a light-transmitting portion and a non-transmitting portion the non-transmitting portion being composed of a slanted face an incident angle of incoming light to which is set larger than the critical angle, the both portions being alternately formed on a protruding mark area formed on a part of a translucent member; light projecting device for illuminating the optical scale; and photoelectric converting device for converting the light, modulated by the optical scale, into electrical signal.