Browse Prior Art Database

Paper Stack Height Control

IP.com Disclosure Number: IPCOM000089211D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Bishop, JL: AUTHOR [+2]

Abstract

A stack 10 of cut sheet paper is supported by vertically movable elevator 11 whose height is controlled by operation of reversible motor 12. The stack's top sheet cooperates with a friction feed roller 13. Roller 13 is spring-biased down into the stack, and is operable to feed the stack's top sheet in direction 14. As sheets are fed away from the stack, motor 12 is controlled to maintain the top of the stack, as shown in Fig. 1. Stack height is sensed by switching mechanism 15, which includes a pivoting actuator arm 16 and two switches 17 and 18.

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Paper Stack Height Control

A stack 10 of cut sheet paper is supported by vertically movable elevator 11 whose height is controlled by operation of reversible motor 12. The stack's top sheet cooperates with a friction feed roller 13. Roller 13 is spring-biased down into the stack, and is operable to feed the stack's top sheet in direction 14.

As sheets are fed away from the stack, motor 12 is controlled to maintain the top of the stack, as shown in Fig. 1. Stack height is sensed by switching mechanism 15, which includes a pivoting actuator arm 16 and two switches 17 and 18.

As shown in Fig. 2, switch 17 comprises a normally closed switch. This switch is shown in the open condition which the switch assumes when arm 16 senses that the stack is at the proper height. Switch 18 is a normally closed switch. As paper is fed away from the stack, arm 16 lowers until switch 17 closes. An "up" energizing circuit is then established for motor 12 through a series connection of switch 17's normally closed contact and switch 18's normally closed contact. In normal operation, switch 17 oscillates between an open and closed condition as motor 12 raises elevator 11 in discrete step-like increments.

In the event that the height of stack 10 should raise beyond that desired, as by swelling of the stack due to high humidity, switch 18 will be transferred, opening its normally closed portion and closing its normally open portion. This completes a "down" energizing circuit for motor 12,...