Browse Prior Art Database

Forms Velocity Control for Printers

IP.com Disclosure Number: IPCOM000092145D
Original Publication Date: 1968-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Barcomb, JG: AUTHOR [+2]

Abstract

The operation of printer forms tractor 2 at high speed is controlled to prevent excess of forms from causing a jam between tractor 2 and feed rolls 4. Forms 1 are fed by tractor 2 and feed rolls 4. The operating speed of tractor 2 is controlled via Driver circuitry by low- and high-speed latches 5A and 5B which are set by a command signal. Rolls 4 are operated at a constant speed which is intermediate the high and low speeds of tractor 2.

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Forms Velocity Control for Printers

The operation of printer forms tractor 2 at high speed is controlled to prevent excess of forms from causing a jam between tractor 2 and feed rolls 4. Forms 1 are fed by tractor 2 and feed rolls 4. The operating speed of tractor 2 is controlled via Driver circuitry by low- and high-speed latches 5A and 5B which are set by a command signal. Rolls 4 are operated at a constant speed which is intermediate the high and low speeds of tractor 2.

Capacitor C is provided with discharging circuit comprising transistor T1 and resistors R1 and R2 which has discharging rate corresponding to operating speed of rolls 4. Two separate charging circuits are provided for capacitor C. Charging circuit comprising T4 and R3 has a charging rate corresponding to the low speed and charging circuit comprising T7 and R4 has charging rate corresponding to high speed of tractor 2. Transistors T2 and T3 and T5 and T6 control switching of T4 and T7 in response to latches 5A and 5B respectively.

In low-speed operation in which latch 5A is set, capacitor C is charged through T4 and R3 while it is discharged through T1, R1, and R2. Since the discharging rate is greater than charging rate, capacitor C is not sufficiently charged to turn off transistor T8 which is normally conducting. In high-speed operation in which both latches 5A and 5B are set, capacitor C is charged through both T4 and R3 and T7 and R4. Since the charging rate is greater than discharging rat...