Image transfer device for an image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsYuko Harasawa, Itaru Matsuda, Satoshi Takano, Akio Kutsuwada, Hirokazu Ishii
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Abstract
In an image transfer device for an image forming equipment, a bias for image transfer is applied from a power source to an endless transfer belt via a bias roller. A current from the Transfer belt is released to ground via a ground electrode. Transfer control means variably controls a current I.sub.1 output from the power source that the difference between the current I.sub.1 and a current I.sub.2 flowing from the power source to the ground via the transfer belt, i,e., I.sub.out =I.sub.1 -1.sub.2 remains at a preselected target current. Setting means sets the target current on the basis of a set condition or conditions.
Claims30
An image transfer device comprising:
- an image carrier for carrying a toner image thereon;
- an endless transfer belt for carrying a sheet thereon and transferring the toner image from said image carrier to said sheet;
- a first electrode for applying a bias for image transfer to said transfer belt in contact with part of said transfer belt facing said image carrier;
- a second electrode contacting said transfer belt;
- a power source for applying the bias to said first electrode;
- transfer control means for variably controlling, assuming that a current output from said power source is I.sub.1, and a current to flow from said power source to said second electrode via said transfer belt ls I.sub.2, said current I.sub.1, such that I.sub.1 -I.sub.2 =I.sub.out remains at a predetermined target current;
- and
- setting means for setting said target current from one of a plurality of target values, said one of a plurality of target values is determined on the basis of a set condition.
An image transfer device comprising:
- an image carrier for carrying a toner image thereon;
- movable transferring means contacting a surface of said image carrier for transferring the toner image from said image carrier to a transfer side;
- a power source for applying a bias for image transfer to said transferring means;
- transfer control means for maintaining a current to be fed from said transferring means to said image carrier during image forming at a predetermined target current;
- mode selecting means for selecting and inputting a desired image forming mode;
- and
- setting means for setting said target current from one of a plurality of target values, said one of a plurality of target values is determined on the basis of a set condition based on the mode selected.
An image transfer device comprising:
- an image carrier for carrying a toner image thereon;
- movable transferring means contacting a surface of said image carrier for transferring the toner image from said image carrier to a transfer side;
- a power source for applying a bias for image transfer to said transferring means;
- transfer control means for maintaining a current to be fed from said transferring means to said image carrier during image forming at a predetermined target current;
- size sensing means for sensing a size of a sheet, on which an image is to be formed, as measured at least in a direction perpendicular to a sheet transport direction;
- and
- setting means for setting said target current from one of a plurality of target values, said one of a plurality of target values is determined on the basis of a set condition based on the sheet size sensed.
An image transfer device comprising:
- an image carrier for carrying a toner image thereon;
- movable transferring means contacting a surface of said image carrier for transferring the toner image from said image carrier to a transfer side;
- a power source for applying a bias for image transfer to said transferring means;
- transfer control means for maintaining a current to be fed from said transferring means to said image carrier during image forming at a predetermined target current;
- mode selecting means for selecting and inputting a desired image forming mode;
- and
- setting means for setting said target current from one of a plurality of target values, said one of a plurality of target values is determined on the basis of a plurality of set conditions.
Dependencies are inferred from the claim text.