Canon Kabushiki Kaisha

Hisatoshi Baba

Hirotake Ando

Shinji Sakai

Osamu Koyama

Kenji Tamaki

Masayuki Usui

Yoshihiko Watanabe

Hideo Nakajima

Tadashi Kato

Tsukasa Ogino

Tomoyuki Hiroki

Yasuyuki Miyaoka

Isao Hayashi

Masaaki Naoi

Takashi Fukuhara

Yoshihiro Saga

Yuri Mori

Hisae Shimizu

Takaaki Aoyagi

Toru Miyazawa

Makoto Shiho

Shuhei Hamada

Naoki Imokawa

Tatsuru Seki

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.

Speed detection apparatus and driving mechanism control apparatus

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.

Belt driving device and image forming apparatus

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.

Heating apparatus for heating a toner image and image forming apparatus including the same

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.

Image forming apparatus

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.

Information-reproducing apparatus equipped with PLL circuit

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 circuit.

Optical information recording/reproducing apparatus with mechanism for correcting spherical aberration and method using same

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.

Optical information recording/reproducing apparatus and method with

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. Another optical information recording and/or reproducing apparatus includes an actuator for moving the light beam relative to the medium in a direction traversing the tracks of the medium, a velocity detecting circuit for detecting a velocity of the actuator and outputting a real velocity signal, a circuit for generating a target moving velocity of the light beam, a control loop for controlling the velocity of the actuator, based on the real velocity signal and target velocity signal, a filter for differentiating the real velocity signal, and an adder for adding an output from the filter to a signal in the control loop.

Optical information recording and/or reproducing apparatus improved in

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.

Optical information recording and/or reproducing apparatus and method

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.

Information recording and reproducing apparatus with offset compensation

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.

Optical information recording and or reproducing apparatus and method

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.

Information recording/reproducing apparatus with counter means

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.

Magnetooptical disc apparatus having single micro-processor for

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.

Automatic loop gain control apparatus

In an automatic gain control device, an error signal generated based on output signals from a divided sensor is inputted to an operational amplifier. A sum signal of the output signals from the divided sensor is inputted to a multiplier. The error signal is divided by the sum signal by negatively feeding back an output signal from the operational amplifier to the operational amplifier via the multiplier. Two predetermined voltages are alternately applied to the multiplier in a state in which the sum signal is 0. The amplitudes of output signals from the automatic gain control device corresponding to the two voltages are detected. Input offsets of the operational amplifier and the multiplier are cancelled by calculating the input offsets of the operational amplifier and the multiplier on the basis of the detected amplitudes of the signals, the two predetermined voltages, and a gain of the multiplier.

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Yokohama, Japan

Hisatoshi Baba