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US 11,143,989 B2Granted
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsTetsuya Ohta, Yutaka Kakehi, Toshiyuki Yamada
Life of this patent
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Abstract
An image forming apparatus includes an image bearing member, a transfer member, a voltage source, a current detecting portion, a controller, and a receiving portion. During the recording material passing through the transfer portion, the controller controls a voltage applied to a transfer member on the basis of a detection result of the current detecting portion so that a current flowing through the transfer member falls within a predetermined range. The controller sets at least one of an upper limit and a lower limit of the predetermined range on the basis of a predetermined voltage changing instruction received by the receiving portion.
Claims21
An image forming apparatus comprising:
- an image forming portion configured to form a toner image;
- an intermediate transfer belt to which the toner image formed by the image forming portion is transferred;
- an inner roller in contact with the inner surface of the intermediate transfer belt;
- a transfer member forming a transfer portion for transferring the toner image from the intermediate transfer belt to the recording material in cooperation with the inner roller;
- a voltage source configured to apply a voltage to the transfer portion;
- a current detecting portion configured to detect current information on a current flowing through the transfer portion;
- a controller configured to control the voltage source, wherein the controller is configured to perform constant voltage control so that the voltage applied from the voltage source becomes a target voltage in a case in which the detection result detected by the current detecting portion is within a predetermined range, which is defined by at least one of an upper limit value and a lower limit value determined based on the type of the recording material during passage of the recording material through the transfer portion, and wherein in a case in which the detection result is out of the predetermined range during passage of the recording material through the transfer portion, the controller is configured to adjust the target voltage so that the detection result falls within the predetermined range, and perform the constant voltage control with the adjusted target voltage;
- and
- an operating portion configured to input an instruction from an operator to change the target voltage,
- wherein the controller is configured to adjust at least one of the upper limit value and the lower limit value of the predetermined range on the basis of the instruction inputted from the operating portion.
7 more elements
An image forming apparatus comprising:
- an image forming portion configured to form a toner image;
- an intermediate transfer belt to which the toner image formed by the image forming portion is transferred;
- an inner roller in contact with the inner surface of the intermediate transfer belt;
- a transfer member forming a transfer portion for transferring the toner image from the intermediate transfer belt to a recording material in cooperation with the inner roller;
- a voltage source configured to apply a voltage to the transfer portion;
- a current detecting portion configured to detect information on a current flowing through the transfer portion;
- and
- a controller configured to control the voltage source,
- wherein the controller is configured to perform constant voltage control so that the voltage applied from the voltage source becomes a target voltage in a case in which a detection result detected by the current detecting portion is within a predetermined range, which is defined by at least one of an upper limit value and a lower limit value determined based on the type of the recording material during passage of the recording material through the transfer portion, and wherein in a case in which the detection result of the current detecting portion is out of the predetermined range during passage of the recording material through the transfer portion, the controller is configured to adjust the target voltage so that the detection result falls within the predetermined range, and perform the constant voltage control with the adjusted target voltage, and
- wherein in continuous image formation for continuously forming images on a plurality of recording materials, in a case in which the detection result is out of the predetermined range and the target voltage is adjusted during passage of a first recording material through the transfer portion, the controller determines the target voltage to be applied during passage of a leading end portion of a second recording material, which follows the first recording material, through the transfer portion, on the basis of the adjusted target voltage adjusted during passage of the first recording material through the transfer portion.
7 more elements
Dependencies are inferred from the claim text.