There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.

An optical position-measuring device for determining a relative position of scales includes a light source, the scales and a detector. The scales are movable relative to each other along measurement directions and disposed in different planes in crossed relation to each other, and each have a graduation having grating regions which are arranged periodically and have different optical properties. At the first scale, the illumination beam is split into sub-beams, the sub-beams subsequently impinge on the second scale and are reflected back toward the first scale, and the reflected-back sub-beams strike the first scale again, where they are recombined, so that a resulting signal beam subsequently propagates toward the detector. The measuring graduation of one or more of the scales is configured as a two-dimensional cross grating which has a filtering effect that suppresses disturbing higher diffraction orders.

An encoder includes rotatable plate including first and second patterns, light emission unit, and light receiving unit. The first pattern includes first and second unit regions. The first unit regions guide the light from light emission unit to the light receiving unit. The second unit regions are configured not to guide light from the light emission unit to the light receiving unit. The second pattern includes first and second unit regions. The first unit regions of the second pattern guide light from light emission unit to the light receiving unit. The second unit regions of the second pattern are configured not to guide light from the light emission unit to the light receiving unit. The first and second unit regions of the first pattern are reverse to the first and second unit regions of the second pattern in a direction perpendicular to a rotation direction of the rotatable plate.

An intermediate transfer member (ITM) (210, 310, 320, 330, 400, 410, 420, 430, 500, 520, 540, 600, 700, 802) configured for receiving ink droplets to form an ink image thereon and for transferring the ink image to a target substrate (226), the TTM (210, 310, 320, 330, 400, 410, 420, 430, 500, 520, 540, 600, 700, 802) includes one or more layers (273, 277, 373, 379, 602, 604, 606, 608, 610, 704, 706, 708, 712) and one or more markers (33, 333, 335, 392, 408, 418, 428, 448, 458, 612, 710, 804, 806) integrated with at least one of the one or more layers (273, 277, 373, 379, 602, 604, 606, 608, 610, 704, 706, 708, 712) at one or more respective marking locations along the ITM (210, 310, 320, 330, 400, 410, 420, 430, 500, 520, 540, 600, 700).

A method of operating a position encoder apparatus, including a scale having features defining position information and a readhead for reading the scale. The method includes: calculating extrapolated position information from at least one previous reading of the scale; comparing an extrapolated position with a position calculated from a reading of the scale to determine any discrepancy between them; using the extrapolated position information whether or not there is a discrepancy; and maintaining a record of any discrepancies.

There is provided an optical positioning system including a detected surface, an optical sensor, a register and a processor. The detected surface has interleaved bright regions and dark regions arranged in a transverse direction. The optical sensor captures an image frame of the detected surface within a field of view thereof and using a shutter time, wherein the detected surface and the optical sensor have a relative movement in the transverse direction. The register records a type of a last passed edge. The processor calculates a first position using a first algorithm upon the recorded last passed edge being a bright-to-dark edge and the field of view being aligned with one of the dark regions, and calculates a second position using a second algorithm, different from the first algorithm, upon the recorded last passed edge being a dark-to-bright edge and the field of view being aligned with the same one of the dark regions.

An optical position measuring device for recording a relative position of two scales includes the scales. The longitudinal extents of the scales are oriented parallel to a first and second measuring direction. A horizontal plane of movement is spanned by these measuring directions. A light source is configured to emit an illumination beam that is split into at least two sub-beam bundles at the first scale. The sub-beam bundles subsequently impinge on the second scale, which is tilted about the direction of the longitudinal extent thereof relative to the horizontal plane of movement, and are back-reflected to impinge again on the first scale and are recombined there such that a resulting signal beam is subsequently propagated toward a detection unit, via which phase-shifted scanning signals are generatable with respect to a relative movement of the scales along a third perpendicular measuring direction and the first or second measuring direction.

There is provided an optical encoder including an encoding medium and a substrate. The encoding medium has a relative movement with respect to the substrate in a predetermined direction. The substrate includes an index photodiode and two control photodiodes. The index photodiode is arranged between the two control photodiodes along the predetermined direction. The output signals of the two control photodiodes are for controlling ON/OFF of gain regulation on an output signal of the index photodiode so as to turn on the gain regulation within an interval during which the index photodiode does not generate an index pulse but to turn off the gain regulation within an interval during which the index photodiode generates the index pulse.

There is provided an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals from an amplifier and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

An optical position-measuring device for determining the position of a first object relative to a second object movable relative to the first object along a measurement direction includes a scale with a measuring graduation connected to the first object and extending along the measurement direction. A scanner is connected to the second object and includes a fiber-optic array including optical fibers. The fiber-optic array is configured as a fiber-optic plate having an image-input face facing the scale and an image-output face facing the detector array. The fiber-optic array transmits a light pattern into a detection plane of the detector array. An interstitial medium is disposed between the image-output face of the fiber-optic plate and the detector array to ensure that an amount of deflection that the beams exiting the image-output face undergo on a path to the detector array is smaller than in a case without the interstitial medium.