Ricoh Company, Ltd.

Tomohiko Kamatani

Katsuhisa Furuse

Haruyuki Suzuki

Fumihiro Shimizu

Hiroaki Kyogoku

Tetsuroh Tatebe

Akitoshi Mochida

Hironobu Tani

A light deflection device includes a reflector; a drive beam supporting the reflector such that the reflector is movable; a supporting section supporting the drive beam; and a piezoelectric drive circuit disposed on the drive beam. The light deflection device further includes circuitry configured to output a first drive-voltage waveform and a second drive-voltage waveform to the piezoelectric drive circuit. The first drive-voltage waveform has a period of a positive slope within one cycle, the period of the positive slope includes a period of a first slope and a period of a second slope different from the first slope. The second drive-voltage waveform has a period of a negative slope within one cycle, and the period of the negative slope includes a period of a third slope and a period of a fourth slope different from the third slope.

Light deflection device, image projector, laser head lamp, and mobile object

A signal level adjustment apparatus includes a detector configured to detect both a plurality of peak levels of an input signal having a sinusoidal waveform or a substantially sinusoidal waveform and a plurality of bottom levels of the input signal; and a level adjuster configured to adjust, in a predetermined zone of the input signal, levels of the input signal based on the plurality of peak levels and the plurality of bottom levels detected by the detector.

Signal level, adjustment apparatus, phase detection apparatus, motor drive controller, conveyer, image forming apparatus, and signal level adjustment method

A phase detecting device includes a signal level detector configured to detect a first level of a signal according to a phase of a rotor of a motor, a level memory configured to store the first level of the signal preliminarily detected at each phase of the rotor as a second level of the signal at the phase of the rotor, and a phase detector configured to detect the phase of the rotor based on the second level of the signal inputted from the signal level detector.

Phase detecting device, motor system, image forming apparatus, conveyance device, and sensor level obtaining method

A semiconductor laser driver and an image forming apparatus incorporating the semiconductor laser driver. The semiconductor laser driver includes a light source including a plurality of laser-beam source units disposed in a sub-scanning direction that serves as a group direction, the laser-beam source units having a plurality of groups arranged in a main scanning direction, each of the laser-beam source units emitting a laser beam of a light quantity dependent upon a driving current, a shading corrector to correct, according to at least one shading correction value, the driving current given to the laser-beam source units for each of the groups, and a light quantity adjuster to adjust the driving current according to a light-quantity adjustment value for the laser-beam source units. The image forming apparatus includes a semiconductor laser drive circuit, and the semiconductor laser driver that serves as the semiconductor laser driver.

Semiconductor laser driver and image forming apparatus incorporating same

An angle detecting device, generating phase information for indicating phases corresponding to rotational positions of a rotor of a motor, comprises an intersection detecting unit, configured to detect timing at which paired sensor signals intersect with each other, and to detect points of intersection; an intersection level detecting unit configured to detect intersection levels that are amplitude levels of the sensor signals, based on the timing at which the respective pairs of the sensor signals intersect with each other; an intersection level adjusting unit configured to adjust the detected intersection levels of the sensor signals to a certain amplitude level, and to output a successively selected one of the adjusted sensor signals as an intersection level adjustment signal; and a phase information detecting unit configured to generate detection results indicative of whether the intersection level adjustment signal is greater than respective threshold levels corresponding to the phases, thereby generating the phase information responsive to the detection results.

Angle detecting device, motor drive controlling device, motor device and method of controlling an angle detecting device

A phase detector is provided. The phase detector includes a signal selector, a bias level generator, and a phase information detector. The signal selector selects, as a selected sensor signal, one of a plurality of sensor signals each having a signal level corresponding to a phase of a rotor. The bias level generator divides a signal level difference between a pair of sensor signals, including the selected sensor signal and other sensor signal of the plurality of sensor signals other than the selected sensor signal, at a first ratio, to generate a first bias level. The phase information detector generates a threshold level corresponding to the phase of the rotor based on the first bias level, and detects the signal level of the selected sensor signal reaching the threshold level.

Phase detector, motor drive controller, motor apparatus, sheet feeder, and method of detecting phase

A phase detector includes a crossing-point phase detection circuit to compare signals levels of pairs of sensor signals and output crossing-point phase detection signals indicating phases of crossing points between the pairs of the sensor signals, each having a signal level corresponding to a rotational position of a rotor of a motor having coils, a crossing-point level detection circuit to output crossing-point level signals indicating crossing-point levels detected, a signal selection circuit to select one of the sensor signals as a selection signal, a phase detection circuit to detect that a signal level of the selection signal has reached a threshold level, and output a phase data signal indicating a phase of the rotor corresponding to the threshold level, and an in-phase level adjustment circuit to adjust and output in-phase levels of the sensor signals to approach each of the crossing-point levels to a predetermined signal level.

Phase detector, motor drive controller, motor device, and method of detecting phase of rotor

A voltage level detector is provided. The voltage level detector includes a comparator and a threshold level changer. The comparator compares a voltage level of an increasing or decreasing input signal with a threshold level, and generates and outputs a voltage level detection signal indicating that the input signal has reached the threshold level. The threshold level changer changes the threshold level of the comparator based on the voltage level detection signal by increasing the threshold level when the input signal is monotonically increasing and decreasing the threshold level when the input signal is monotonically decreasing.

Voltage level detector, motor drive controller, motor apparatus, and method of detecting voltage level

A phase detector includes a crossing-point phase detection circuit to compare signals levels of pairs of sensor signals and output crossing-point phase detection signals indicating phases of crossing points between the pairs of the sensor signals, each having a signal level corresponding to a rotational position of a rotor of a motor having coils, a crossing-point level detection circuit to output crossing-point level signals indicating crossing-point levels detected, a signal selection circuit to select one of the sensor signals as a selection signal, a phase detection circuit to detect that a signal level of the selection signal has reached a threshold level, and output a phase data signal indicating a phase of the rotor corresponding to the threshold level, and a threshold-level correction circuit to correct the threshold level based on the crossing-point level signals.

A motor drive controller to control a motor via multiple sensors includes a first phase detector to compare respective differential pairs of the sensor signals from the same sensor to detect phases of the rotor, and output a first phase information signal; a second phase detector to compare a respective one of the multiple sensor signals with another sensor signal from the different sensor to detect the phases and output a second phase information signal; a phase divider to divide the phases, detected by the first and second phase detectors, into multiple predetermined phase intervals; a signal selector to select one of the multiple sensor signals in the multiple predetermined phase intervals; and a third phase detector to detect whether the signal selected by the signal selector reaches a predetermined threshold level corresponding to a predetermined phase of the rotor, and output a third phase information signal.

Motor drive controller and control method

A motor drive controller to drive a motor, based on multiple sensors that generates multiple sensor signals corresponding to different positions of the rotor; including a first phase detector to compare a respective one of the multiple sensor signals with a paired sensor signal from the same sensor to detect phases of the rotor, and output a first phase information signal representing a first detected phase; a phase divider to divide the phases, detected by the first phase detector into multiple predetermined phase intervals; a signal selector to select one of the respective multiple sensor signals from the multiple sensors in the multiple predetermined phase interval; and a second phase detector to detect whether the signal selected by the signal selector reaches a predetermined threshold level corresponding to a predetermined phase of the rotor, and output a second phase information signal representing a second detected phase.

Disclosed is an angle detection device including plural sensors that output corresponding sinusoidal signals, wherein each of the sinusoidal signals varies sinusoidally depending on a rotational angle of a rotor of a motor, and each of the sinusoidal signals has a phase that depends on a position of the corresponding sensor; a vector generating unit that generates a vector represented by a result of mutually operating at least two of the sinusoidal signals; a vector rotation unit that rotates the vector by operating the vector and reference sine waves having corresponding phases; and an angle search unit that causes the vector rotation unit to sequentially rotate the vector until a phase of the vector becomes a predetermined phase, and that detects an angle between the vector prior to being rotated and the predetermined phase as the rotational angle of the rotor of the motor.

Angle detection device, motor driving device, and image forming apparatus

A semiconductor laser driving device that drives a semiconductor laser with a driving current output from a driving current output terminal is disclosed. The semiconductor laser driving device includes a driving current monitoring terminal configured to output a driving current monitoring current having a value of 1/&#x3b1; of the driving current; a current-voltage conversion resistor connected to the driving current monitoring terminal and configured to convert the driving current monitoring current having the value of 1/&#x3b1; of the driving current into a corresponding driving current monitoring voltage; and a detector configured to generate a reference voltage and detect whether the corresponding driving current monitoring voltage has reached the reference voltage.

Semiconductor laser driving device and image forming apparatus having the semiconductor laser driving device

A laser diode drive circuit includes a power supply circuit connected to an anode of a laser diode to supply a variable voltage to the laser diode, and a drive current control circuit connected to a cathode of the laser diode to control a current of the laser diode. The power supply circuit generates a start-up voltage which is equal to the sum of the maximum drive voltage that is larger than the drive voltage and a predetermined first reference voltage, acquires a cathode voltage of the laser diode while the start-up voltage is generated, generates a voltage by lowering from the start-up voltage so as to diminish the difference between the acquired cathode voltage and the first reference voltage, and the first reference voltage is the minimum cathode voltage necessary to supply a predetermined current to the laser diode by the drive current control circuit.

Laser diode drive circuit

Disclosed is a receiving device that includes a differential input circuit having an inverting input terminal and a non-inverting input terminal to which the differential signal is input; an abnormality detection circuit that detects an abnormality in a wiring connected to the inverting input terminal and the non-inverting input terminal; and a control circuit that sets an output signal of the receiving device in a predetermined status when the abnormality is detected. The abnormality detection circuit detects the abnormality if a status, in which a potential difference between a voltage of the inverting input terminal and a voltage of the non-inverting input terminal is less than a minimum potential difference in a predetermined range of the potential difference between the voltage of the inverting input terminal and the voltage of the non-inverting input terminal, continues for a predetermined time or more.

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Hyogo, Japan

Tomohiko Kamatani