In accordance with the preferred embodiment of the invention, a cam-operated idler roller assembly maintains tension on a computer printer generated form as it advances through the print station of a computer printer. This invention provides a nip station that disengages on a print medium reversal to allow the form to be run in a reverse direction through the print station by means of a cam design that disengages the idler roller assembly from the drive roller. The cam design further allows the idler roller assembly to reengage on forward print media movement to reestablish tension in the printing station.

A continuous form tractor drive is disposed out of the way and out of sight below the printing platen (which itself may be capable of feeding individual forms to a print station). The mechanical paper handling and printing mechanism is affixed to the upper portion of a hinged housing with the continuous form tractor drive mechanism depending therefrom such that, when rotated upwardly and rearwardly to an opened position, easy access is provided for loading paper into the continuous form paper drive.

A sheet feeding apparatus in a printer is provided with: feeding rollers for holding and feeding a sheet of paper therebetween; and an operation lever for changing the contact pressure of the feeding rollers by attaching or detaching the feeding roller to or from the opposite feeding roller depending on a type of sheet, e.g., a continuous form transferred by pin tractors or a manually inserted cut sheet. The operation lever also connects or disconnects a clutch mechanism provided between a drive motor and the pin tractors simultaneously with the attaching/detaching operation for the feeding rollers. A single operation of the operation lever can achieve a precise transfer of a selected type of sheet while suspending another type of sheet in the printer. The sheet feeding apparatus is also provided with a transmission mechanism for transmitting a torque between the platen and the feeding rollers by a friction driving force. The transmission mechanism prevents the inertia force of the platen from the rotating the feeding rollers uselessly.

A system for automatically releasing selected plural sheet feeding nip sets spaced along a print media sheet feeding path of a printer, wherein the idler rollers are rotatably mounted on common idler shafts and a selectable partial rotation system driven by a single low cost motor is flexibly connected to those plural idler shafts to partially rotate eccentric lift cams on each idler shaft into the underlying surface as to lift the idler shaft and thereby move the idler rollers away from their normally mating sheet feed rollers to release all the sheet feeding nips, enabling sheet deskew, inversion, acceleration, deceleration, or sheet jam clearance in that selected area of the sheet feeding path.

A sheet feeding apparatus in a printer is provided with: feeding rollers for holding and feeding a sheet of paper therebetween; and an operation lever for changing the contact pressure of the feeding rollers by attaching or detaching the feeding roller to or from the opposite feeding roller depending on a type of sheet, e.g., a continuous form transferred by pin tractors or a manually inserted cut sheet. The operation lever also connects or disconnects a clutch mechanism provided between a drive motor and the pin tractors simultaneously with the attaching/detaching operation for the feeding rollers. A single operation of the operation lever can achieve a precise transfer of a selected type of sheet while suspending another type of sheet in the printer. The sheet feeding apparatus is also provided with a transmission mechanism for transmitting a torque between the platen and the feeding rollers by a friction driving force. The transmission mechanism prevents the inertia force of the platen from rotating the feeding rollers uselessly.