Image forming system
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, andwherein the application time of the cleaning bias is a fixed value regardless of a length of the sheet feeding interval.
1 Assignment
0 Petitions
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.
-
Citations
20 Claims
-
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, 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, and wherein the application time of the cleaning bias is a fixed value regardless of a length of the sheet feeding interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. 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 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 application time Z to an increased length of time as the sheet feeding interval is increased, and wherein the controller is to set an end of application of the cleaning bias immediately before an end of the sheet feeding interval. - View Dependent Claims (13, 14)
-
-
15. An image forming apparatus comprising:
-
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.
-
-
16. An image forming system comprising:
-
an image forming apparatus; and a sheet processing apparatus for post-processing a sheet, wherein the image forming apparatus includes; 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 the 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,wherein, when the sheet feeding interval does not exceed the predetermined threshold, the controller causes the bias application device to apply the non-image area bias for the application time Z within the sheet feeding interval, wherein the controller sets the application time Z to an increased length of time as the sheet feeding interval is increased, and wherein the predetermined condition includes an operating condition of the sheet processing apparatus. - View Dependent Claims (17, 18, 19, 20)
-
Specification