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US 6,006,062 AGranted
Image transferring method using an intermediate transfer body and image forming apparatus for practicing the same
AssigneeRicoh Company, Ltd.
InventorsMitsuru Takahashi, Hiroyuki Sugimoto
Life of this patent
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Abstract
In an image forming apparatus, a potential deposited on the rear of a transfer body is selected to be zero or of the same polarity as the charge of an image carrier at least at a part of a nip formed for image transfer. In this condition, image transfer conditions allowing a minimum of toner scattering to occur at the time of image transfer are set up against, e.g., a change in the resistance of the transfer body ascribable to aging. Therefore, an image with a minimum of toner scattering is achievable.
Claims26
An image forming apparatus comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- a reducing electrode for causing, at at least a part of said contact position, a potential deposited on said transfer member to be zero or of a same polarity as a charge deposited on said image carrier,
- wherein said reducing electrode contacts a side of said transfer body opposite to a side contacting said image carrier,
- wherein said reducing electrode comprises a rotatable body, and
- wherein said transfer body comprises an intermediate transfer body for temporarily supporting the toner image transferred from said image carrier at said contact position and then transferring said toner image to a recording medium.
3 more elements
An image forming apparatus comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- a reducing electrode for causing, at at least a part of said contact position, a potential deposited on said transfer member to be zero or of a same polarity as a charge deposited on said image carrier,
- wherein said reducing electrode contacts a side of said transfer body opposite to a side contacting said image carrier,
- wherein said reducing electrode comprises a rotatable body, and
- wherein said transfer body comprises a conveyor member for supporting a recording medium and conveying, after the toner image has been transferred from said image carrier to a sheet at said contact position, said sheet to a next step.
3 more elements
An image forming apparatus comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- a reducing electrode for causing, at at least a part of said contact position, a potential deposited on said transfer member to be zero or of a same polarity as a charge deposited on said image carrier,
- wherein said reducing electrode contacts a side of said transfer body opposite to a side contacting said image carrier,
- wherein said reducing electrode comprises a rotatable body, and
- wherein said transfer body has a volume resistivity of 10.sup.7 .OMEGA.cm to 10.sup.13 .OMEGA.cm.
3 more elements
An image forming apparatus, comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- potential measuring means for measuring a potential Vnip at said contact position;
- and
- a reducing electrode for causing, at at least a part of said contact position, a potential deposited on said transfer member to be zero or of a same polarity as a charge deposited on said image carrier;
- wherein that said image carrier and said transfer body start contacting each other at a position O is a direction of movement of said transfer body, and start leaving each other at a position L in said direction, said potential measuring means measures said potential Vnip at a position X lying in a range of O.ltoreq.X.ltoreq.L/2 of said contact position.
3 more elements
An image forming apparatus, comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- potential measuring means for measuring a potential Vnip at said contact position;
- a reducing electrode for causing, at at least a part of said contact position, a potential deposited on said transfer member to be zero or of a same polarity as a charge deposited on said image carrier;
- and
- first operation control means for causing said potential measuring means to perform measurement in an image transfer step, and second operation control means for controlling an operation of image forming means such that said potential Vnip is zero or of a same polarity as a charge deposited on said image carrier.
3 more elements
An image forming apparatus comprising:
- an image carrier for forming a toner image thereon by being charged;
- a transfer body held in contact with said image carrier at a contact position for transferring the toner image to a recording medium by an electric field for image transfer formed at said contact position;
- and
- a reducing electrode connected to ground for reducing said transfer electric field;
- wherein a current Inip to flow from said reducing electrode to ground is selected to be smaller than zero inclusive when said image carrier is chargeable to a negative polarity or greater than zero inclusive when said image carrier is chargeable to a positive polarity.
2 more elements
Dependencies are inferred from the claim text.