Canon Kabushiki Kaisha

Rikuo Kawakami

Kenichi Ogawa

Noriyuki Ito

Yasuhiro Shimura

Noriaki Sato

Takatoshi Tanaka

An image forming apparatus includes an attachment portion to which any one of a first fixing apparatus and a second fixing apparatus is selectively attached, and a power supply circuit including a plurality of power supply paths. The first fixing apparatus includes a plurality of first heating elements grouped into a plurality of groups, and a number of the plurality of groups is equal to a number of the plurality of power supply paths. The second fixing apparatus includes at least one second heating element grouped into at least one group whose number is smaller than the number of the power supply paths. In a state where the second fixing apparatus is attached to the image forming apparatus, a power supply path of the plurality of power supply paths in which a power line has a largest allowable current value is electrically connected with the at least one second heating element.

Image forming apparatus

An image forming apparatus including a first output unit configured to detect a light beam deflected by a rotary polygon mirror rotated by a drive unit to output a first signal, a second output unit configured to output a second signal to be used as a reference, and a first controller configured to perform the phase control based on the first signal and the second signal. The phase control is performed in accordance with a condition set based on a rotation speed of the drive unit corresponding to an image forming speed by outputting a drive signal having a predetermined pulse width to the drive unit to accelerate or decelerate the drive unit so that the first signal and a position signal, based on the second signal, substantially match. The condition being a pulse width of the drive signal and/or a frequency of performing the phase control.

One disclosed aspect of the embodiments relates to power control of a heater in a fixing unit. A plurality of control tables having different ratios of phase control waveforms and wave number control waveforms in one control cycle have been set, and a control table is selected depending on a set target temperature.

Image forming apparatus using power control to select power levels based on temperature

An image forming apparatus includes an image bearing member, a charger for electrically charging the member, an electrostatic latent image forming device for forming an electrostatic latent image on the member, a developer for developing the electrostatic latent image into a toner image, a transferer for transferring the toner image from the member onto a recording material and including a transfer member to which a transfer voltage is to be applied, a transfer-voltage source variably setting the transfer voltage, and a circuit for detecting a current passing between the image bearing and the transfer members by the transfer voltage applied from the voltage source, and a controller for controlling the voltage source. The controller sets the transfer-voltage value, applied from the voltage source during a non-passing period of the recording material, so that a predetermined current is detected by the circuit.

The image forming apparatus has a heat member for heating an unfixed image and is configured so that a longitudinal center of the heat member becomes a conveyance center of the recording material, the image forming apparatus including a central portion temperature detection part adjacent to the conveyance center, an end portion temperature detection part for detecting an end portion temperature of the heat member, and a width detection part for detecting a lateral width of the recording material, wherein the width detection part is disposed at a side opposite to a side at which the end portion temperature detection part is disposed with respect to the conveyance center position of the recording material. A control part controls a power supply or conveyance interval of the heat member in accordance with the presence/absence sensor, top sensor, width sensor, central portion temperature sensor, and end portion temperature sensor.

Image forming apparatus with a presence or absense sensor

An image forming apparatus has a heat member configured so that a longitudinal center becomes a conveyance center of the recording material, the apparatus also having a central portion temperature detection part for detecting a temperature of the heat member corresponding to the conveyance center or adjacent thereto, a one side end portion temperature detection part for detecting one end portion temperature at one side in a longitudinal direction of the heat member, and an other side end portion temperature detection part for detecting an other end portion temperature on the other side in the longitudinal direction of the heat member, and a control part for controlling the image forming apparatus based on heat member temperature information detected by the central portion temperature detection part, the one side end portion temperature detection part, and the other side end portion temperature detection part.

The image forming apparatus has a heat member for heating an unfixed image and is configured so that a longitudinal center of the heat member becomes a conveyance center of the recording material, the image forming apparatus including a central portion temperature detection part adjacent to the conveyance center, an end portion temperature detection part for detecting an end portion temperature of the heat member, and a width detection part for detecting a lateral width of the recording material, wherein the width detection part is disposed at a side opposite to a side at which the end portion temperature detection part is disposed with respect to the conveyance center position of the recording material. The image forming apparatus achieves the control for error setting of the recording material based on the width detection part and the end portion temperature detection part.

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Numazu, Japan

Rikuo Kawakami