Canon Kabushiki Kaisha

Takashi Uehara

Satoshi Ogawara

An image forming apparatus includes: a heating unit including a heating rotation member configured to heat a recording medium: a pressure rotation member which contacts the heating rotation member to form a nip portion to fix a toner image to the recording medium, a heat source configured to heat the heating rotation member, the heat source including a first heater and a second heater, and a control unit configured to control the first heater and the second heater, wherein the image forming unit is operable to transition to: a fixing state in which an operation to fix the toner image to the recording medium is performed by receiving a job; and a standby state, to wait for the job, in which an operation to fix the toner image to the recording medium is not performed.

Image forming apparatus

A fixing unit includes a first heater, a first switch, a second heater, and a second switch. In an image forming mode, a controller controls the first switch and the second switch to keep a temperature of the fixing unit at a fixing temperature serving as a target temperature for fixing the image on the sheet. In a standby mode, the controller controls the first and second switches to keep the temperature of the fixing unit at a standby temperature, and controls the first and second switches such that a period in which a first current is supplied to the first heater and a period in which a second current is supplied to the second heater do not overlap.

Image forming apparatus for controlling heater of fixing unit powered by two power sources

A power supply apparatus includes: a detection circuit configured to feed back a voltage to a generation circuit. The detection circuit includes: a first resistor, a second resistor connected in series with the first resistor, a first conductive pattern configured to connect the first resistor and the second resistor in series, a first capacitor connected in parallel to the first resistor, a second capacitor connected in parallel to the second resistor and connected in series with the first capacitor, a second conductive pattern configured to connect the first capacitor and the second capacitor in series, and a third conductive pattern configured to electrically connect the first conductive pattern and the second conductive pattern. A thermal resistance of the third conductive pattern is greater than a thermal resistance of the first conductive pattern.

Power supply including resistors

An image forming apparatus includes an image bearing drum; a drum charging member, disposed at a charging position opposed to the drum, for applying the drum with a charging bias; a developing member for developing an electrostatic image formed on the drum with toner, with a developing bias; a transfer member for transferring a toner image from the drum onto a sheet, with a transfer bias; a transfer bias source for outputting the transfer bias; and a controller for effecting control to start raising of the transfer bias so as to correspond to a timing at which an area of the drum passing at a timing of starting of raising of the charging bias passes the transfer position and to complete the raising of the transfer bias so as to correspond to a timing at which an area of the drum passing at a timing of completion of raising of the charging bias passes the transfer position.

Image forming apparatus controlling charging bias and transfer bias

A charging bias output portion is controlled so that a direct-current component of a charging bias voltage reaches a target voltage value taking a first set time after output start. A transfer bias output portion is controlled so that output of a transfer bias is started after a first position of an image bearing member reaches a transfer position and before a second position reaches the transfer portion, and a transfer current reaches a target current value taking a second set time. The first position is a position of the image bearing member that passes through a charging portion between a charging member and the image bearing member at a timing when the output of the charging DC is started, and the second position is a position that passes through the charging portion at a timing when the charging DC reaches the target voltage value.

Image forming apparatus that prevents image defects and reduces first copy output time

A developing device for developing an electrostatic latent image on an image carrier by using developer includes a developing bias output unit configured to output a developing bias generated by superimposing an AC bias on a DC bias, a developing sleeve supplied with the developing bias output from the developing bias output unit, and a prevention bias generator unit configured to generate a prevention bias by holding a peak value of the developing bias of the superimposed AC bias and DC bias, with the prevention bias suppressing scattering of developer carried by the developing sleeve. In addition, an electrode is disposed at a position opposing the developing sleeve and configured to output the prevention bias.

Developing device and image forming apparatus that generate prevention bias for suppressing scattering of developer

An image forming apparatus which is capable of reducing the number of times a second member is separated from a first member upon entry into power-save mode, thereby minimizing failures of a separation unit. A pressure-roller separating mechanism is provided so as to abut and separate a pressure roller and a fixing roller against/from each other. The image forming apparatus is controlled to change to a power-save mode in which power consumption of the image forming apparatus is reduced. The pressure-roller separating mechanism is controlled to separate the pressure roller and the fixing roller from each other in the power-save mode based on a measurement result measured by a timer, and the power-save mode is maintained after the pressure roller and the fixing roller are separated from each other.

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Kashiwa, Japan

Takashi Uehara