Abstract: A light receiving sensor (1) includes: a photodiode (PD) which generates a photocurrent (Ipd) upon receipt of light; a transistor (Tr11) through which the photocurrent (Ipd) flows; a transistor (Tr12) which forms, together with the transistor (Tr11), a first current mirror circuit (CM1); a transistor (Tr9) whose channel type is different from that of the transistor (Tr11), and a resistor (R10) which converts, to a voltage, a current flowing through the transistors (Tr11 and Tr12). The first current mirror circuit (CM1) amplifies the photocurrent (Ipd), the transistor (Tr11) has a source connected with a gate of a MOS transistor (Tr9), and the MOS transistor (Tr9) has a threshold voltage that is set to be equal to or above a threshold voltage of the transistor (Tr11). This decreases a capacity of the photodiode (PD) and therefore allows the light receiving sensor (1) to operate at a high speed while the photodiode (PD) is biased.

Abstract: A fixing control device includes an image detection unit that determines presence of an image in each of areas obtained by division of an image formation region in which the image is formed, a heater selection unit that selects from heaters of a fixing device heaters at positions corresponding to areas in which the presence of the image is determined, a heating amount computation unit that computes a heating amount of a heating area heated by each of the selected heaters in a fixing region corresponding to the image formation region, a change amount computation unit that computes an amount of change of the heating amount between adjoining ones of the heating areas, and a heating amount correction unit that corrects one of the heating amounts of the adjoining heating areas so that the amount of change after the correction is less than a predetermined threshold.

Abstract: A power source device includes: a first voltage generating unit that includes a power storage unit storing power based on power supplied from a power source and generates a voltage to be supplied to a first load based on the power supplied from the power source; and a second voltage generating unit that generates a voltage to be supplied to a second load based on the power stored in the power storage unit when the first voltage generating unit is controlled to stop generation.

Abstract: An image forming apparatus includes a heat-generating component, a power generation device including a thermoelectric element, a heat radiation device, a cooling device, a temperature detector that detects a temperature increase of the heat-generating component, and a controller. The heat radiation device includes a first radiator plate interposed between the heat-generating component and a surface of the thermoelectric element and a second radiator plate attached to another surface of the thermoelectric element. The cooling device cools the first radiator plate. The controller controls operations of the cooling device and the power generation device by operating the cooling device if the detected temperature increase reaches at least a predetermined threshold value, and causing the power generation device to generate power without operating the cooling device to cool the first radiator plate passively if the detected temperature increase falls below the predetermined threshold value.

Abstract: A fixing control device includes an image detection unit that determines presence of an image in each of areas obtained by division of an image formation region in which the image is formed, a heater selection unit that selects from heaters of a fixing device heaters at positions corresponding to areas in which the presence of the image is determined, a heating amount computation unit that computes a heating amount of a heating area heated by each of the selected heaters in a fixing region corresponding to the image formation region, a change amount computation unit that computes an amount of change of the heating amount between adjoining ones of the heating areas, and a heating amount correction unit that corrects one of the heating amounts of the adjoining heating areas so that the amount of change after the correction is less than a predetermined threshold.

Abstract: The optical sensor includes a photodiode PD1 with its anode grounded, a diode group DG1 having one end connected to a cathode of the photodiode PD1, a current source I1 having one end connected to the other end of the diode group DG1, a power supply section for applying a constant voltage to the other end of the current source I1, and a grounded-emitter NPN transistor QOUT1 having a base connected to the cathode of the photodiode PD1 and a collector connected to one end of the current source I1. The diode group DG1 is provided by n diodes D1, D2, . . . , Dn connected in series so that their forward directions are directed toward the photodiode PD1 side, and a photocurrent which flows from a connecting point between the diode group and the current source to the photodiode is converted into a voltage and outputted as a photoelectric conversion signal.

Abstract: An image forming apparatus and a method of monitoring power consumption of the image forming apparatus are provided. For each one of parts of the image forming apparatus selected for monitoring, part-specific power consumption information is obtained based on accumulated operation amount information. The obtained part-specific power consumption information is used to generate power consumption information indicating an amount of electric power consumed by at least a portion of the image forming apparatus.

Abstract: An image forming apparatus includes a heating unit, a storage unit, and a setting unit. The heating unit uses electric power and performs a heating operation in accordance with a print condition specified in a print job to thermally fix a developer onto a recording medium. The storage unit stores therein output priorities, which are determined for different print conditions based on power consumption in a heating operation, so as to be associated with their corresponding print conditions. In outputting a plurality of print jobs having different print conditions successively, the setting unit sets output order of the print jobs to be output in accordance with the output priorities.

Abstract: A heater control device includes a temperature detector that detects a temperature of a heated object heated by a heater; an alternating-current power supply for applying an alternating current voltage to the heater; a turn-on ratio decision unit that determines a turn-on ratio of the heater based on the temperature and a target temperature; a turn-on pattern decision unit that determines a partial turn-on pattern, as the turn-on pattern of the heater, which is a pattern of a turn-on ratio higher than the determined turn-on ratio in terms of a control-period, and to which a partial turn-on instead of a full turn-on is allocated on a half-wavelength basis of the alternating current voltage within the control period based on the turn-on ratio of the heater; and a turn-on controller that controls turn-on of the heater based on the determined turn-on pattern.

Abstract: A power source device includes: a first voltage generating unit that includes a power storage unit storing power based on power supplied from a power source and generates a voltage to be supplied to a first load based on the power supplied from the power source; and a second voltage generating unit that generates a voltage to be supplied to a second load based on the power stored in the power storage unit when the first voltage generating unit is controlled to stop generation.

Abstract: When no light enters a photodiode, a second current mirror circuit operates. Consequently, a current that decreases a potential difference between two terminals of a light-receiving element flows into a transistor of the second current mirror circuit and an output of an optical sensor becomes low. Meanwhile, when light enters the photodiode, a transistor of the light-receiving element is turned on and the second current mirror circuit stops operating. Consequently, the current that decreases the potential difference between the two terminals of the light-receiving element is stopped in the transistor of the second current mirror circuit and the output of the optical sensor becomes high. This makes it possible to provide an optical sensor that has a circuit in which an output of a light-receiving element does not depend on a photocurrent and that is capable of operating at a high speed.

Abstract: An image forming apparatus includes a halogen heater in a fixing unit; an AC source applying an alternating voltage to the halogen heater; a half-wave control unit that performs the heater half-wave control to control the halogen heater on the half-wavelength basis, according to a heater-on/off pattern set for each control cycle having a predetermined length; a heater-off-time measuring unit that measures heater-off period of time; a phase-control-execution determining unit that determines, based on the measured heater-off period of time, whether the heater phase control is to be performed on the alternating voltage, the phase control being performed by shifting phase of the alternating voltage; and a phase control unit that performs, when the phase control is determined to be performed, the phase control only for a period of time depending on the measured heater-off period of time after switch-on of the heater and before execution of the half-wave control.

Abstract: The optical sensor includes a photodiode PD1 with its anode grounded, a diode group DG1 having one end connected to a cathode of the photodiode PD1, a current source I1 having one end connected to the other end of the diode group DG1, a power supply section for applying a constant voltage to the other end of the current source I1, and a grounded-emitter NPN transistor QOUT1 having a base connected to the cathode of the photodiode PD1 and a collector connected to one end of the current source I1. The diode group DG1 is provided by n diodes D1, D2, . . . , Dn connected in series so that their forward directions are directed toward the photodiode PD1 side, and a photocurrent which flows from a connecting point between the diode group and the current source to the photodiode is converted into a voltage and outputted as a photoelectric conversion signal.

Abstract: A heater controlling apparatus for controlling supply of alternating current power to at least one heater that heats a heating object includes a detection unit configured to detect a temperature of the heating object, a determining unit configured to determine a proportion of lighting time for lighting the heater based on the detected temperature and a preset target temperature of the heating object, and a control unit configured to control the supply of alternating current power to the heater based on both a control cycle and one or more lighting patterns, the heater being lit according to the one or more lighting patterns defined for each control cycle, and both the control cycle and the lighting pattern varying in response to the determined proportion of lighting time.

Abstract: A decoder device has a reference voltage generating section for outputting first and second threshold level signals, a first comparator for comparing a stair-stepped waveform input signal and the first threshold level signal to output a comparison result, a second comparator for comparing the input signal and the second threshold level signal to output a comparison result, and a logical operation section for performing a logical operation between output signals of the first and second comparators to output a signal decoded from the input signal. A threshold level represented by the first threshold level signal intersects a riser section of one stepped waveform out of two adjacent stepped waveforms in the input signal, and a threshold level represented by the second threshold level signal intersects a riser section of the other stepped waveform out of the two adjacent stepped waveforms of the stair-stepped waveform input signal.

Abstract: A control unit controls supply of power to a plurality of heating units at predetermined control period T1 that is set by a first unit. A second unit sets power supply time t1 for a first heating unit having largest power consumption within the control period T1 and power supply time t2 for a second heating unit having second largest power consumption. A third unit controls to supply the power to the first heating unit for the power supply time t1 from beginning of the control period T1 and to supply the power to the second heating unit from a point obtained by subtracting the power supply time t2 from end of the control period T1 to the end of the control period T1.

Abstract: In a fixing device, a fixing unit fixes a toner image transferred onto a recording medium by a heating target unit heated by a plurality of heating units each of which is grouped as a first heating unit to which power is selectively supplied or a second heating unit to which power is supplied in priority to the first heating unit, and a supply control unit supplies power to a heating unit grouped as the second heating unit and selectively supplies power to a heating unit grouped as the first heating unit, among the heating units that heat the heating target unit of which detected temperature by a detecting unit is lower than a target temperature.

Abstract: This optical encoder includes a light emitting section and a plurality of light receiving elements placed so as to be aligned in one direction in an area where a light beam from the light emitting section may reach. A moving object includes a light-ON section, a light-OFF section and an index pattern section. The light receiving element outputs a first light receiving signal when the light-ON section and the light-OFF section of the moving object pass through a predetermined position corresponding to the light receiving element. The light receiving element outputs a second light receiving signal when the index pattern section of the moving object passes through a predetermined position corresponding to the light receiving element.

Abstract: A heater control device includes a temperature detector that detects a temperature of a heated object heated by a heater; an alternating-current power supply for applying an alternating current voltage to the heater; a turn-on ratio decision unit that determines a turn-on ratio of the heater based on the temperature and a target temperature; a turn-on pattern decision unit that determines a partial turn-on pattern, as the turn-on pattern of the heater, which is a pattern of a turn-on ratio higher than the determined turn-on ratio in terms of a control-period, and to which a partial turn-on instead of a full turn-on is allocated on a half-wavelength basis of the alternating current voltage within the control period based on the turn-on ratio of the heater; and a turn-on controller that controls turn-on of the heater based on the determined turn-on pattern.

Abstract: An image forming apparatus and a method of monitoring power consumption of the image forming apparatus are provided. For each one of parts of the image forming apparatus selected for monitoring, part-specific power consumption information is obtained based on accumulated operation amount information. The obtained part-specific power consumption information is used to generate power consumption information indicating an amount of electric power consumed by at least a portion of the image forming apparatus.