IMAGE FORMING APPARATUS
First Claim
1. An image forming apparatus comprising:
- an image bearer to rotate and bear a toner image;
a transfer rotator to rotate and contact the image bearer to form a transfer nip therebetween;
a bias application device to apply multiple biases to the transfer rotator, the multiple biases including;
a transfer bias to transfer the toner image from the image bearer onto a sheet transported to the transfer nip,a cleaning bias to remove toner adhering to the transfer rotator, anda non-image area bias smaller in absolute value than the cleaning bias; and
a controller to control the bias application device and set a sheet feeding interval according to a predetermined condition, the sheet feeding interval being a period from when the sheet is sent out from the transfer nip to when a subsequent sheet is fed to the transfer nip while multiple sheets are successively fed to the transfer nip,wherein, when the sheet feeding interval exceeds a predetermined threshold, the controller causes the bias application device to apply the non-image area bias for an application time Z within the sheet feeding interval and apply the cleaning bias for an application time expressed as X−
Z within the sheet feeding interval, X representing the sheet feeding interval, andthe controller sets the application time Z to an increased length of time as the sheet feeding interval is increased.
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Accused Products
Abstract
An image forming apparatus includes an image bearer; a transfer rotator to contact the image bearer to form a transfer nip therebetween; a bias application device to apply, to the transfer rotator, a transfer bias, a cleaning bias to remove toner adhering to the transfer rotator, and a non-image area bias smaller in absolute value than the cleaning bias; and a controller to control the bias application device and set a sheet feeding interval according to a predetermined condition. When the sheet feeding interval exceeds a predetermined threshold, the controller causes the bias application device to apply, to the transfer rotator, the non-image area bias for an application time Z and the cleaning bias for a time X−Z within the sheet feeding interval when X represents the sheet feeding interval, and the application time Z is increased as the sheet feeding interval is increased.
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Citations
13 Claims
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1. An image forming apparatus comprising:
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an image bearer to rotate and bear a toner image; a transfer rotator to rotate and contact the image bearer to form a transfer nip therebetween; a bias application device to apply multiple biases to the transfer rotator, the multiple biases including; a transfer bias to transfer the toner image from the image bearer onto a sheet transported to the transfer nip, a cleaning bias to remove toner adhering to the transfer rotator, and a non-image area bias smaller in absolute value than the cleaning bias; and a controller to control the bias application device and set a sheet feeding interval according to a predetermined condition, the sheet feeding interval being a period from when the sheet is sent out from the transfer nip to when a subsequent sheet is fed to the transfer nip while multiple sheets are successively fed to the transfer nip, wherein, when the sheet feeding interval exceeds a predetermined threshold, the controller causes the bias application device to apply the non-image area bias for an application time Z within the sheet feeding interval and apply the cleaning bias for an application time expressed as X−
Z within the sheet feeding interval, X representing the sheet feeding interval, andthe controller sets the application time Z to an increased length of time as the sheet feeding interval is increased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An image forming apparatus comprising:
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an image bearer to rotate and bear a toner image; a transfer rotator to rotate and contact the image bearer to form a transfer nip therebetween; a backup roller disposed to contact the transfer rotator via the image bearer; a bias application device to apply multiple biases to at least one of the transfer rotator and the backup roller, the multiple biases including; a transfer bias to transfer the toner image from the image bearer onto a sheet transported to the transfer nip, a cleaning bias to remove toner adhering to the transfer rotator, and a non-image area bias smaller in absolute value than the cleaning bias; and a controller to control the bias application device and set a sheet feeding interval according to a predetermined condition, the sheet feeding interval being a period from when the sheet is sent out from the transfer nip to when a subsequent sheet is fed to the transfer nip while multiple sheets are successively fed to the transfer nip, wherein, when the sheet feeding interval exceeds a predetermined threshold, the controller causes the bias application device to apply the non-image area bias for an application time Z within the sheet feeding interval and apply the cleaning bias for an application time expressed as X−
Z within the sheet feeding interval, X representing the sheet feeding interval, andthe controller sets the time application Z to an increased length of time as the sheet feeding interval is increased.
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13. An image forming apparatus comprising:
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an image bearer to bear a toner image; a transfer rotator to rotate and contact the image bearer to form a transfer nip therebetween; a bias application device to apply, to the transfer rotator, a transfer bias to transfer the toner image from the image bearer onto a sheet transported to the transfer nip and a cleaning bias; and a controller to control the bias application device, wherein the controller causes the bias application device to keep a value of current applied to the transfer rotator at zero for an application time Z and apply the cleaning bias for an application time expressed as X−
Z within an interval between sheets in successive feeding of sheets, X representing the interval between sheets,and the controller sets the application time Z to an increased length of time as the interval between sheets is increased.
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Specification