Abstract: A speed detection apparatus includes a storage unit configured to store time when each of first and second sensors detects an arbitrary detection mark and an address corresponding to the detection mark. The speed detection apparatus further includes a same mark detection time identification unit configured to identify, based on output information from a reference speed detection unit, time when the first and second sensors detect the same mark, based on the address and the time stored in the storage unit, and a relative speed calculation unit configured to calculate, based on output information from the same mark detection time identification unit, a speed of the first sensor and the second sensor relative to a scale member.

Abstract: A belt driving device includes first and second steering rollers to stretch an endless belt, first and second pivoting mechanisms, and first and second detecting members to detect a position of the belt A first setting portion sets first and second pivoting instruction values through which the first and second steering rollers are pivoted in the same direction, and a second setting portion sets third and fourth pivoting instruction values through which the first and second steering rollers are pivoted in the opposite directions. A controller pivots the first steering roller by the first pivoting mechanism on the basis of an addition value of the first pivoting instruction value and the third pivoting instruction value, and pivots the second steering roller by the second pivoting mechanism on the basis of an addition value of the second pivoting instruction value and the fourth pivoting instruction value.

Abstract: A non-contact power supply unit including a secondary coil supplies an alternating voltage to multiple heat generation layers provided in a heat generation film. In one of the heat generation layers, a loop is provided as a variable impedance circuit in which the impedance changes according to the frequency. A capacitance element in which the impedance changes according to the frequency is provided in the loop. The heat generation amounts of the heat generation layers are switched by changing the frequency of the alternating voltage generated in the secondary coil according to the size of the recording material that is the heating target.

Abstract: An image forming apparatus includes a rotatable image bearing member provided with a mark; a driving portion for rotationally driving the image bearing member; a first detecting portion for detecting speed information of the image bearing member by detecting the mark moved in a predetermined first distance; a second detecting portion for detecting speed information of the image bearing member by detecting the mark moved in a second distance shorter than the predetermined first distance; a filter circuit for suppressing a high-frequency part of an output from the detecting portion and a low-frequency part of an output from the second detecting portion; a calculating portion for calculating a speed of the image bearing member detected from an output from the filter circuit; and a controller for controlling the driving portion so that the calculated speed of the image bearing member is a set speed.

Abstract: A belt driving device for driving an endless belt includes rollers configured to stretch the belt, the rollers including first and second steering rollers being provided in an upstream side and a downstream side of an image receiving surface of the belt for receiving a image, respectively, and being configured to change a position of the belt in a direction crossing with a moving direction of the belt by inclining respectively; a pivoting unit configured to pivot the first and second steering rollers, respectively; a detecting unit for detecting an inclination amount of the belt with respect to a feeding direction of the belt; and a controller configured to pivot the first and second steering rollers in the same direction by the pivoting unit on the basis of a result of detection of the detecting unit.

Abstract: A non-contact power supply unit including a secondary coil supplies an alternating voltage to multiple heat generation layers provided in a heat generation film. In one of the heat generation layers, a loop is provided as a variable impedance circuit in which the impedance changes according to the frequency. A capacitance element in which the impedance changes according to the frequency is provided in the loop. The heat generation amounts of the heat generation layers are switched by changing the frequency of the alternating voltage generated in the secondary coil according to the size of the recording material that is the heating target.

Abstract: A speed detection apparatus includes a storage unit configured to store time when each of first and second sensors detects an arbitrary detection mark and an address corresponding to the detection mark. The speed detection apparatus further includes a same mark detection time identification unit configured to identify, based on output information from a reference speed detection unit, time when the first and second sensors detect the same mark, based on the address and the time stored in the storage unit, and a relative speed calculation unit configured to calculate, based on output information from the same mark detection time identification unit, a speed of the first sensor and the second sensor relative to a scale member.

Abstract: An image forming apparatus includes a rotatable image bearing member provided with a mark; a driving portion for rotationally driving the image bearing member; a first detecting portion for detecting speed information of the image bearing member by detecting the mark moved in a predetermined first distance; a second detecting portion for detecting speed information of the image bearing member by detecting the mark moved in a second distance shorter than the predetermined first distance; a filter circuit for suppressing a high-frequency part of an output from the detecting portion and a low-frequency part of an output from the second detecting portion; a calculating portion for calculating a speed of the image bearing member detected from an output from the filter circuit; and a controller for controlling the driving portion so that the calculated speed of the image bearing member is a set speed.

Abstract: The present invention provides highly reliable PLL without influence of variations in amplitude of a reproduced signal or variations in inclination of an edge. An information-reproducing apparatus according to the present invention includes a unit for detecting a phase difference between a reproduced signal and a reproducing clock signal, a PLL circuit for regulating a frequency of the reproducing clock signal to compensate for the detected phase difference, a unit for detecting a state of the PLL circuit, and a unit for regulating a loop gain of the PLL circuit corresponding to the detected state.

Abstract: An optical information recording/reproducing apparatus is provided that condenses a light flux from a light source on an optical recording medium and effects recording/reproduction and comprises a light source; an objective lens; a spherical aberration generating mechanism; a sensor for receiving light reflected by an optical recording medium and converting the light into an electric signal; an equalization filter for effecting waveform equalization of an output from the sensor in accordance with a predetermined partial response characteristic; a quality evaluating circuit for measuring reproduction quality of an output signal from the equalization filter; and an adaptive equalization circuit for sequentially updating a coefficient for the equalization filter, wherein while the update of the coefficient for the equalization filter by the adaptive equalization circuit is stopped, the spherical aberration generating mechanism is driven on the basis of the reproduction quality measured by the quality evaluating

Abstract: An optical information recording/reproducing apparatus is provided that condenses a light flux from a light source on an optical recording medium and effects recording/reproduction and comprises a light source; an objective lens; a spherical aberration generating mechanism; a sensor for receiving light reflected by an optical recording medium and converting the light into an electric signal; an equalization filter for effecting waveform equalization of an output from the sensor in accordance with a predetermined partial response characteristic; a quality evaluating circuit for measuring reproduction quality of an output signal from the equalization filter; and an adaptive equalization circuit for sequentially updating a coefficient for the equalization filter, wherein while the update of the coefficient for the equalization filter by the adaptive equalization circuit is stopped, the spherical aberration generating mechanism is driven on the basis of the reproduction quality measured by the quality evaluating

Abstract: The present invention provides highly reliable PLL without influence of variations in amplitude of a reproduced signal or variations in inclination of an edge. An information-reproducing apparatus according to the present invention includes a unit for detecting a phase difference between a reproduced signal and a reproducing clock signal, a PLL circuit for regulating a frequency of the reproducing clock signal to compensate for the detected phase difference, a unit for detecting a state of the PLL circuit, and a unit for regulating a loop gain of the PLL circuit corresponding to the detected state.

Abstract: An optical information recording/reproducing apparatus for recording and/or reproducing information on or from both a land portion and a groove portion of a recording medium using a light beam includes a focus servo for adjusting a focus state of the light beam, and a tracking servo for adjusting a tracking state of the light beam. Parameters of the tracking servo and focusing servo are checked in state in which the light beam is being traced on the land portion and in a state in which the light beam is being traced on the groove portion, respectively. The focus servo and/or the tracking servo adjusts the focus state and/or tracking state of the light beam on the basis of the parameters.

Abstract: An optical information recording and/or reproducing apparatus, for performing at least one of recording and reproduction of information as irradiating a recording medium with a light beam, includes an actuator for moving the light beam relative to the medium, a position detecting circuit for detecting a position of the actuator, a circuit for generating a relative position error signal of the light beam to the medium, a control loop for controlling the actuator in accordance with the relative position error signal, a filter for differentiating an output from the position detecting circuit, and an adder for adding an output from the filter to a signal in the control loop.

Abstract: An optical information recording and/or reproducing apparatus for carrying out at least one of recording and reproduction of information by projecting a light beam condensed by an objective lens onto an information track of a recording medium, includes a detecting device for detecting an inclination of an optical axis of the objective lens with respect to a direction perpendicular to a surface of the recording medium and a control device for inhibiting recording or reproduction of information, based on a detection result of the detecting device.

Abstract: In an optical information recording/reproducing apparatus provided with an actuator for integrally moving a mirror and an objective lens in the focusing direction, there are provided a device for receiving a light beam reflected by an information medium thereby detecting a tracking error signal indicating deviation of the light beam from an information track, a device for measuring an offset value utilizing the tracking error signal, and a device for correcting the offset contained in the tracking error signal. The offset correcting device corrects the offset at the tracking servo operation, based on the offset value measured by the offset measuring device.

Abstract: An optical information recording and/or reproducing apparatus includes an optical head for irradiating an optical information recording medium having a plurality of information tracks with a light beam, a photosensor which detects light received via the optical information recording medium and is split into a plurality of sections, and signal generating device for generating a focusing error signal, a tracking error signal, and a sum signal as a sum total of outputs from the split sections of the photosensor on the basis of outputs from the photosensor. In the apparatus, a correction signal is generated such that the phase and amplitude of the correction signal match a phase and an amplitude of crosstalk components included in the focusing error signal on the basis of the tracking error signal and the sum signal obtained when the light beam crosses the information tracks. The correction signal is applied to a focusing servo loop so as to cancel the crosswalk components included in the focusing error signal.

Abstract: An information recording/reproducing apparatus for executing recording of information on and/or reproduction of information from a recording medium, upon reception of an instruction from a host computer. The apparatus includes (1) a single calculation device for, alternatively and time-divisionally, performing (i) a system processing for handling the instruction from the host computer and (ii) a seek processing for moving an information reproduction head to a target track, and (2) a counter, incorporated into the calculation device. In the seek processing, the number of tracks which the head has traversed is counted and, in the system processing, the number of tracks thus counted is monitored and the information to be reproduced by the head is prepared based on the monitored number of tracks.

Abstract: Input/output processing of information is controlled in a magnetooptical disc apparatus for recording and/or reproducing the information on a magnetooptical recording medium by irradiating a desired track of the recording medium with a light beam via an optical system. The servo control of the light beam such as tracking servo control, focusing servo control or the like is performed by causing interruption in the input/output processing control. When the apparatus activates, a parameter in the servo control is set on the basis of a reproduction signal amplitude of the information with a change in state of the servo control and a parameter in signal processing of the information is set in accordance with a reproduction signal amplitude of the information corresponding to the set parameter for the servo control.

Abstract: An automatic loop gain control apparatus in a servo control apparatus of a closed loop arrangement which positions a control object with respect to a reference. The apparatus includes an adder for adding a reference signal of a predetermined frequency to a control signal in the closed loop, a first detector for detecting a peak value of predetermined frequency components of the control signal in a state before the control signal is input to the adder at every predetermined cycle, a second detector for detecting a peak value of predetermined frequency components of an output output from the adder at every predetermined cycle, and a digital signal processor for performing a digital computation using the peak value detected by the first detector and the peak value detected by the second detector and for adjusting the gain of the control loop on the basis of the result of the computation.