Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: The heating apparatus including a plurality of heat generation members including first, second and third generation members, the second heat generation member and the third heat generation member having lengths in a longitudinal direction shorter than a length of the first heat generation member, the heating apparatus including first, second, third, and fourth contacts, and a first switching unit configured to bring an electric path between the second contact and the fourth contact into one of a connecting state and an open state.

Abstract: A power supply device generates an output voltage by driving a piezoelectric transformer using a frequency signal. The power supply device includes a comparison unit configured to compare an output voltage and a voltage setting signal that sets the output voltage, and a voltage control oscillation unit configured to generate the frequency signal to drive the piezoelectric transformer based on comparison results of the comparison unit. The voltage control oscillation unit generates the frequency signal within a range between the resonant frequency and a spurious resonant frequency closest to the resonant frequency.

Abstract: A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, an output voltage control circuit which controls an output voltage from the piezoelectric transformer, and includes a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal. The power supply unit also includes a driving frequency supplying circuit which generates a driving frequency signal of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the driving frequency signal to the piezoelectric transformer. The time constant of the output voltage control circuit is longer than the time constant of the output voltage detecting circuit.

Abstract: An image forming apparatus including an AC high voltage power supply, a DC high voltage power supply, and a high voltage power supply apparatus, which outputs an output voltage at an output end by superposing an output of the AC high voltage power supply and an output of the DC high voltage power supply. The high voltage power supply apparatus has a positive peak detector detecting a positive peak of the voltage at an output end, and a negative peak detector detecting a negative peak of the voltage at an output end. An output voltage of at least one of the AC high voltage power supply and the DC high voltage power supply is controlled on the basis of the detection result of at least one of the positive peak detector and the negative peak detector.

Abstract: A power supply device generates an output voltage by driving a piezoelectric transformer using a frequency signal. The power supply device includes a comparison unit configured to compare an output voltage and a voltage setting signal that sets the output voltage, and a voltage control oscillation unit configured to generate the frequency signal to drive the piezoelectric transformer based on comparison results of the comparison unit. The voltage control oscillation unit generates the frequency signal within a range between the resonant frequency and a spurious resonant frequency closest to the resonant frequency.

Abstract: In an image forming apparatus that judges the type of sheet by using an image pickup device, it is possible to read an image which does not blur and is excellent in precision even if the shutter period of time of the image pickup device is made long, and even in the case of providing a plurality of sheet feeding parts, it is possible to judge the type of sheet more inexpensively. An image read sensor, which is disposed downstream of a junction of a deck and a recording material tray and upstream of a pair of registration rollers on the transport path for the recording material, reads the image within a light irradiated region of the recording material by irradiating a light onto the surface of the recording material when the recording material which is fed to the transport path stops, and sets an image formation condition in accordance with a read output.

Abstract: A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal, and a driving frequency supplying circuit which generates the driving frequency of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the resultant driving frequency to the piezoelectric transformer. The time constant of the output voltage setting signal is longer than the time constant of the output voltage detecting circuit.

Abstract: The image forming apparatus with the high voltage power supply apparatus which includes an AC high voltage power supply and a DC high voltage power supply and which outputs at an output end a voltage of an output voltage of the AC high voltage power supply superposed on an output voltage of the DC high voltage power supply, the high voltage power supply apparatus comprises a positive peak detection circuit and a negative peak detection circuit, and is arranged to control the output voltage of the AC high voltage power supply and the DC high voltage power supply, on the basis of the detection result of the positive peak detection circuit and the negative peak detection circuit.

Abstract: This invention has as its object to provide an image forming apparatus in which the number of beam detectors is decreased and which is low in cost and high in the accuracy of the registration position of an image of each color as well as high in quality.

Abstract: An image forming apparatus is provided which is capable of positively preventing a recording sheet from being wound around a conveying means that conveys the recording sheet. A high voltage power supply section applies voltage to feeding brushes disposed in contact with the surface of a pressurizing roller having an electrically conductive surface. A winding sensor is disposed in contact with the surface of the pressurizing roller and is located in a sheet passing area of the pressurizing roller. A CPU sets a threshold voltage to a value corresponding to the temperature of the pressurizing roller detected by a temperature sensor, and detects whether the recording sheet is wound around the pressurizing roller, based upon the set threshold voltage and voltage of the pressurizing roller in the sheet passing area detected by the winding sensor.

Abstract: This invention has as its object to provide an image forming apparatus in which the number of beam detectors is decreased and which is low in cost and high in the accuracy of the registration position of an image of each color as well as high in quality.

Abstract: In an image forming apparatus that judges the type of sheet by using an image pickup device, it is possible to read an image which does not blur and is excellent in precision even if the shutter period of time of the image pickup device is made long, and even in the case of providing a plurality of sheet feeding parts, it is possible to judge the type of sheet more inexpensively. An image read sensor, which is disposed downstream of a junction of a deck and a recording material tray and upstream of a pair of registration rollers on the transport path for the recording material, reads the image within a light irradiated region of the recording material by irradiating a light onto the surface of the recording material when the recording material which is fed to the transport path stops, and sets an image formation condition in accordance with a read output.

Abstract: A semiconductor device includes a semiconductor laser chip having a first light-emitting surface which is formed on one end face of the semiconductor laser chip and which outputs a plurality of front beams, and a second light-emitting surface which is formed on an end face opposite to the first light-emitting surface and which outputs a plurality of back beams corresponding to the plurality of front beams. A photodetector is so formed on the semiconductor laser device as to face the second light-emitting surface of the semiconductor laser chip. The photodetector has a plurality of photodetecting portions for independently detecting the plurality of back beams output from the second light-emitting surface. The photodetector is in tight contact with the second light-emitting surface of the semiconductor laser chip.

Abstract: An image forming apparatus includes a process cartridge detachably mountable with respect to the main body of the apparatus. The process cartridge is provided with an image bearing member, a charger for charging the image bearing member, a power supply for applying an alternating current voltage to the charger, and a controller for variably controlling the alternating current supplied from the power supply to the charger in conformity with information about the use situation of the process cartridge. The process cartridge can also include an image bearing member, a charger for charging the image bearing member, the charger permitting an alternating current voltage to be applied thereto by a power supply, and a memory for storing therein information about the use situation of the process cartridge, and information of a plurality of preset control values for an alternating current supplied from the power supply to the charger to be variably controlled in conformity with the information.