Adjustable force driving nip assemblies for sheet handling systems

An adjustable force driving nip assembly for use in a sheet handling system of a document creating apparatus having a control panel for sheet media data entry by an end user, comprising:

• a plurality of individual driving nips aligned and spaced transversely across a sheet transport path of said sheet handling system, each individual driving nip of said driving nip assembly having an idler roller mounted on a pivotable cam follower and mated against a driven roller, each of said idler rollers having an associated spring, said springs providing a force on said idler rollers to produce a normal force for said idler rollers that biases said idler rollers toward said driven rollers, and wherein each of said idler rollers have a shaft with opposing ends, said idler rollers being rotatable about said idler roller shafts, said idler roller shafts being coaxially aligned and parallel to said common drive shaft of said driven rollers, said cam follower further comprising a pair of identical cam follower members, each of said cam follower members having an opening intermediate opposite ends thereof with each of said opposing ends of said idler roller shaft being rotatably mounted in an opening in a respective one of said cam follower members, so that said idler rollers are located between respective airs of cam follower members and wherein each of said cam follower members have a recess therein that is located above said cam follower opening and is in communication therewith said recesses in said cam follower members each have a slider adapted to slide therein towards and away from said openings;
• wherein each of said air of cam follower members have a compression spring to provide said force on said idler rollers rotatably mounted therein to produce said normal force for said idler rollers and wherein a one of said compression springs is located in a respective recess in each of said sliders, said compression springs urging said sliders into contact with said idler roller shafts that reside in said openings of said cam follower members;
• said driven rollers of said driving nip assembly being mounted on a common drive shaft having two ends;
• a first stepper motor coupled to one end of said common drive shaft and adapted to interact concurrently with said cam followers upon actuation and thereby vary said force of said springs on said idler rollers to adjust said normal force thereof;
• a memory for storing a plurality of algorithms, each algorithm being representative of a predetermined number of incremental steps from said stepper motor to achieve a desired normal force for said idler rollers;
• a controller for selecting an algorithm from said memory in response to said sheet media data entered into said control panel by an end user and actuating said stepper motor in accordance with said selected algorithm to effect automatically an adjustment of said normal force of said idler rollers, thereby prevent marking of sheets transported by said sheet handling system;
• wherein each of said pair of cam follower members are pivotally mounted at one end with an opposite end thereof having a cam surface;
• and wherein a first cam for each cam surface on said cam follower members is mounted on a common first cam shaft, each of said first cams being in contact with a respective one of said cam surfaces, said common first cam shaft being rotated by said first stepper motor;
• and
• wherein said pivotally mounted ends of said cam follower members are pivotally mounted on a fixed frame member of said sheet handling system for pivoting said cam follower members relative thereto.

A method of automatically adjusting the normal force of idler rollers in an adjustable force driving nip assembly for use in a sheet handling system of a document creating apparatus having a control panel for sheet media data entry by an end user, comprising:

• providing a plurality of individual driving nips aligned and spaced transversely across a sheet transport path of said sheet handling system, each of said driving nips having an idler roller mounted on a pair of cam followers at a location between said pair of cam followers and intermediate opposing ends of said sheet transport path and mated against a driven roller;
• pivotally mounting said pairs of cam followers at one end thereof;
• providing a cam surface on ends of said pairs of cam followers opposite said end that is pivotally mounted;
• biasing at least one idler roller against said driven roller with a spring having a force that produces a normal force for said idler roller and urges said idler roller into contact with said driven roller, and using a compression spring to provide said force that produces said normal force for said idler rollers on each cam follower of said pairs of cam followers, said force by said compression spring being applied at a location on said cam followers between the opposing ends thereof;
• contacting each cam surface on said pairs of cam followers with a cam, each cam being mounted on a common cam shaft and mounting said driven rollers on said common cam shaft;
• driving said common cam shaft by an electric motor;
• adapting a stepper motor to interact concurrently with said cam followers to vary said spring force of said springs and thereby adjust said normal force of said idler rollers by connecting said stepper motor to one end of said common cam shaft, so that bi-directional rotation of said cam shaft adjusts said force from said compression spring;
• storing a plurality of algorithms in a memory, each algorithm being representative of a predetermined number of steps from said stepper motor to achieve a desired normal force for said idler rollers;
• selecting an algorithm from said memory by a controller in response to sheet media data entered into said control panel by an end user;
• and
• actuating said stepper motor in accordance said selected algorithm to effect automatically an adjustment of said normal force of said idler rollers and prevent marking of sheets transported by said sheet handling system.