Printer with variable torque distribution
AssigneeIntermec Corporation
InventorDuane M. Fox
Life of this patent
Estimating the term…
Abstract
A printer includes a variable torque assembly that allows a printer controller to vary torque on supply and take-up reels in response to monitored diameter of the supply or take-up reels. In one embodiment, the variable torque assembly is a torque divider that divides a fixed amount of torque between a supply reel and a take-up reel. The ratio of torques on the supply and take-up reels is controller by a control stepper motor that adjusts respective Acme gears to adjust pressure on respective clutch plates to increase or decrease the amount of "drag" applied by the clutch plates. In another embodiment, separate control stepper motors control torque to each of the supply and take-up reels so that the overall amount of torque can be varied to accommodate changes in print media lengths.
Claims33
A torque divider for a web or tape in a printer, comprising:
- a supply reel;
- a take-up reel;
- a first clutch assembly coupled to the supply reel and having a first torque input, the first clutch assembly including an adjustable first bias member, the first clutch assembly being configured to transfer to the supply reel a portion of a first torque applied to the first torque input in response to a first bias force applied to the first bias member;
- a second clutch assembly coupled to the take-up reel and having a second torque input, the second clutch assembly including an adjustable second bias member, the second clutch assembly being configured to transfer to the take-up reel a portion of a second torque applied to the second torque input in response to a second bias force applied to the second bias member;
- and
- a control motor coupled to the first and second bias members and responsive to a control signal to apply the first and second biasing forces to the first and second bias members, respectively.
A printer, comprising:
- a first motor for providing a driving torque;
- a supply reel rotatable about a first axis for carrying a supply of print medium;
- a take-up reel rotatable about a second axis for taking up print medium;
- a variable torque divider having a torque input coupled to the driver motor, a control input, a first torque output coupled to the first reel, and a second torque output coupled to the second reel, the torque divider being operative to transfer a first portion of the driving torque to the first reel and to transfer a second portion of the driving torque to the second reel, wherein the relative magnitudes of the first and second portions are determined by a control signal at the control input.
A print medium driver apparatus, comprising:
- a driving torque input;
- a torque divider coupled to the driving torque input, the torque divider having a first output and a second output and operative to distribute the driving torque between the first and second outputs in response to a torque control input;
- a supply reel coupled to the first output;
- a take-up reel coupled to the second output;
- and
- a demand sensor coupled to the supply reel or the take-up reel, the demand sensor producing the torque control input in response to a sensed demand of the supply reel or the take-up reel.
A method of driving a print medium through a printer having a supply reel and a take-up reel for supplying and taking up the print medium respectively, comprising the steps of:
- generating a driving torque;
- applying the driving torque to the take-up reel to cause the take-up reel to rotate;
- in response to rotation of the take-up reel, dividing the driving torque into a supply torque and a take-up torque;
- applying the supply torque to the supply reel;
- and
- applying the take-up torque to the take-up reel.
A method of printing on a thermal print medium, the method comprising the steps of:
- turning a first shaft with a first torque;
- establishing a desired tension of the thermal print medium;
- determining an initial reel diameter of a reel carrying a portion of the print diameter;
- in response to the established desired tension and the determined initial reel diameter, transferring a portion of the torque from the first shaft to the first reel;
- monitoring changes in the reel diameter;
- and
- in response to the monitored changes in the reel diameter, adjusting the portion of torque transferred from the first shaft to the first reel.
A method of producing tension in a print medium or a ribbon in a printer, comprising the steps of:
- mounting the print medium or ribbon to a supply reel and a take-up reel;
- producing a driving torque;
- applying the torque to a shaft;
- coupling a first portion of the applied torque from the shaft to the take-up reel;
- coupling a dragging torque to the supply reel;
- determining a diameter of the supply or take-up reel;
- and
- in response to the determined diameter, inversely varying the magnitudes of the first portion of the torque and the dragging torque.
Dependencies are inferred from the claim text.