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US 10,372,071 B2Granted
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorYusuke Minato
Life of this patent
Estimating the term…
Abstract
An image forming apparatus includes an image bearing member, a transfer roller, a power feeding rotary member, and a controller. The controller is configured to execute the cleaning mode such that a period in which the cleaning mode is executed comprises a first application period during which a reverse polarity bias having a polarity reverse to that of the transfer bias is continuously applied to the power feeding rotary member, and a second application period during which a same polarity bias having a same polarity with that of the transfer bias is continuously applied to the power feeding rotary member.
Claims33
An image forming apparatus, comprising:
- an image bearing member configured to bear a toner image;
- a transfer roller comprising a conductive shaft portion and an outer circumferential portion containing a conducting agent and being formed around the shaft portion, the transfer roller forming a transfer portion where the transfer roller is in contact with an outer surface of the image bearing member to transfer the toner image borne on the image bearing member onto a recording medium;
- a power feeding rotary member configured to rotate while in contact with the transfer roller to supply electric current to the transfer roller to transfer the toner image at the transfer portion;
- a power source configured to apply a transfer bias to the power feeding rotary member;
- and
- a controller configured to execute a cleaning mode of cleaning the power feeding rotary member by applying a bias from the power source to the power feeding rotary member to transfer toner adhering on the power feeding rotary member to the image bearing member through the transfer roller in a state that the transfer roller, the power feeding rotary member and the image bearing member are rotating while the transfer roller is in contact with the power feeding rotary member and the transfer roller is in contact with the image bearing member without forming an image,
- wherein the controller is configured to execute the cleaning mode such that a period in which the cleaning mode is executed includes a first application period during which a reverse polarity bias having a polarity reverse to that of the transfer bias is continuously applied to the power feeding rotary member, and a second application period during which a same polarity bias having a same polarity as that of the transfer bias is continuously applied to the power feeding rotary member.
4 more elements
An image forming apparatus, comprising:
- an image bearing member configured to bear a toner image;
- a transfer roller comprising a conductive shaft portion and an elastic layer formed around the conductive shaft portion, the transfer roller forming a transfer portion where the transfer roller is in contact with an outer surface of the image bearing member to transfer the toner image borne on the image bearing member onto a recording medium;
- a power feeding roller configured to rotate while in contact with the transfer roller to supply electric current to the transfer roller to transfer the toner image at the transfer portion;
- a power source configured to apply a transfer bias to the power feeding roller;
- and
- a controller configured to execute a cleaning mode of cleaning the power feeding roller by applying a bias from the power source to the power feeding roller to transfer toner adhering on the power feeding roller to the image bearing member through the transfer roller in a period during which no image is formed,
- wherein the controller is configured to execute the cleaning mode such that a period in which the cleaning mode is executed includes a first period during which a first bias having a polarity reverse to that of the transfer bias is applied to the power feeding roller, and a second period during which a second bias having a same polarity as that of the transfer bias is applied to the power feeding roller.
4 more elements
An image forming apparatus, comprising:
- a belt configured to bear a toner image;
- a transfer roller comprising a conductive shaft and an elastic layer formed around the conductive shaft, the transfer roller forming a transfer nip where the transfer roller is in contact with an outer surface of the belt to transfer the toner image borne on the belt onto a recording medium;
- an opposing roller disposed opposite to the transfer roller through the belt to form the transfer nip;
- a conductive roller configured to rotate while in contact with an outer surface of the transfer roller;
- a power source configured to supply transfer current flowing to a first area and a second area in a transferring period in which image is transferred to the recording medium by applying a transfer bias, the first area being an area between the opposing roller and the transfer roller, the second area being an area where the conductive roller is in contact with the transfer roller;
- and
- a controller configured to execute a cleaning mode in which the power source applies a cleaning bias to transfer toner adhering on the conductive roller to the belt through the transfer roller in a non-transferring period during which no image is transferred to the recording medium,
- wherein a cleaning period in which the cleaning mode is executed includes a first application period during which at least a first bias having polarity reverse to that of the transfer bias is applied by the power source and a second application period during which at least a second bias having a same polarity as that of the transfer bias is applied by the power source.
5 more elements
Dependencies are inferred from the claim text.