Browse Prior Art Database

Limiting Stepper Motor Heating

IP.com Disclosure Number: IPCOM000060394D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Alexander, RW: AUTHOR [+4]

Abstract

To prevent overheating of the paper advance stepper motor in a printer, a timer is used to introduce a delay between uses of the motor. This reduces the duty cycle to a level which does not generate excessive heat. For most normal use, this delay occurs during printing time and throughput is not degraded. For applications with much spacing and little printing, printing may be delayed, and throughput is somewhat degraded. Other known techniques for temperature control, i.e., large heat sinks, fans, bigger motor, reduction of motor speed, etc., are generally more expensive, require more space, or degrade throughput for all applications.

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Limiting Stepper Motor Heating

To prevent overheating of the paper advance stepper motor in a printer, a timer is used to introduce a delay between uses of the motor. This reduces the duty cycle to a level which does not generate excessive heat. For most normal use, this delay occurs during printing time and throughput is not degraded. For applications with much spacing and little printing, printing may be delayed, and throughput is somewhat degraded. Other known techniques for temperature control, i.e., large heat sinks, fans, bigger motor, reduction of motor speed, etc., are generally more expensive, require more space, or degrade throughput for all applications. In the present embodiment, prior tests have determined that a stepper motor that overheats when operated at 100% duty cycle does not exceed a safe operating temperature at a two-thirds duty cycle. This desired duty cycle is achieved by inhibiting a succeeding motor operation for a time interval equal to one half of the preceding motor usage time. Thus, it is seen that, regardless of motor on time for each usage, the average usage time does not exceed two thirds. Referring to Fig 1, it is seen that, when stepper motor 1 is turned on to advance the paper, measurement of motor on time is initiated (2). When the motor turns off, the required delay is calculated (3), the timer is started to measure (4) that delay, and the logic 5 is enabled to proceed with printing. When printing is completed, logic 5 calls...