Method and apparatus for controlling overdrive in a frictionally driven system including a conformable member

Apparatus for controlling a speed ratio in a transfer apparatus of an electrostatographic machine including a conformable toner image bearing member (TIBM) roller rotatable about a first axis of rotation and having a first outer surface, a transfer backup roller (TBR) relatively movable with respect to said TIBM, said TBR rotatable about a second axis of rotation parallel to said first axis, said TBR associated with said TIBM so as to establish a pressure-generated transfer nip, wherein said first outer surface deforms in said pressure-generated transfer nip, and a transport web, captured in said pressure-generated transfer nip between said TIBM and said TBR, for transporting through said transfer nip a receiver member, having a second outer surface, adhered to said transport web wherein when said transport web is moved through said pressure-generated transfer nip, frictionally causes said TBR and said TIBM to rotate in a nonslip condition of engagement, comprising:

• an engagement adjustment device enabling engagement in said pressure-generated transfer nip to be controllably adjusted by relocating one of said first axis and said second axis and keeping both axes mutually parallel in order to change, to a predetermined difference, any difference in speeds between a speed of a first portion of said first outer surface and a speed of a second portion of said second outer surface, the first and second portions being situated away from said pressure-generated transfer nip and located where any distortions caused by the nip are negligible.

In an apparatus having a plurality of image forming modules wherein a plurality of toner images are transferred in register to a receiver member, each module respectively including a primary image forming member and a rotating generally cylindrical conformable intermediate transfer member, respective toner images being formed on each primary image forming member and respectively transferred to each intermediate transfer member in a respective first transfer nip, a method of controlling a magnitude of a speed ratio comprising the steps of:

• advancing a receiver member serially into a respective second transfer nip with each intermediate transfer member to transfer a respective toner image from each intermediate transfer member to said receiver member, the generally cylindrical intermediate transfer member of each module deforming in response to pressure in the respective second transfer nip and being in a substantially nonslip condition of engagement with the receiver member in the respective second transfer nip;
• and
• in each module, adjusting engagement in at least one of the first and second respective transfer nips to control, to a same predetermined value in each module, a ratio of a peripheral speed of each respective intermediate transfer member far from the respective transfer nip, divided by a speed of the receiver in the respective transfer nip, said predetermined value including substantially 1.000.

For use in an electrostatographic machine, an apparatus for adjusting a speed difference between members of a frictionally driven system such that the speed difference is made equal to a predetermined value, said members of said frictionally driven system including a conformable member having a nip relationship with at least one other member, the speed difference adjusting apparatus comprising:

• a plurality of rotatable members having respective operational surfaces, said plurality of rotatable members including a first member having a first operational surface and a second member having a second operational surface, at least one of said plurality of rotatable members being conformable;
• a plurality of pressure nips being produced by engagements between said plurality of rotatable members, said first member being included in one nip only, and no rotatable member being included in more than two nips;
• and
• at least one engagement adjustment device for activation by at least one prime mover for controllably adjusting at least one said engagements for provision of said speed difference between said first operational surface and said second operational surface, which speed difference being related to locations on said first operational surface and said second operational surface far from any said nips.

For use in an electrostatographic machine having a plurality of rotatable members, an operational surface associated respectively with each of said plurality of rotatable members at least one of which is conformable, said plurality of rotatable members including a first member having a first operational surface and a second member having a second operational surface, said plurality of rotatable members being in engagement in pressure nips involving the operational surfaces of said plurality of rotatable members, each pressure nip including an engagement between two of said rotatable members, said first member being included in one nip only, and no rotatable member being included in more than two nips, and a member of said plurality of rotatable members being a driving member causing frictional rotation of all the other rotatable members by a nonslip frictional drive in each of said pressure nips, and an apparatus for controlling a speed ratio between certain of said rotatable members, said apparatus comprising:

• at least one engagement adjustment device including at least one prime mover to controllably adjust at least one of the engagements, wherein said speed ratio, defined as a speed of a first surface portion included in said first operational surface divided by a speed of a second surface portion included in said second operational surface, said first and second surface portions being located where any distortions of said operational surfaces caused by said pressure nips are negligible, is made equal to a predetermined value by activating said at least one engagement adjustment device.