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Proportional Rattle Cycle

IP.com Disclosure Number: IPCOM000036781D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Duncan, RR: AUTHOR [+5]

Abstract

Disclosed is an improved method for rattling hammers to avoid or minimize hammer flight time problems associated with 'morning sickness'.

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Proportional Rattle Cycle

Disclosed is an improved method for rattling hammers to avoid or minimize hammer flight time problems associated with 'morning sickness'.

In the field of impact printing, the 'morning sickness' problem is defined as an unacceptably large change in print hammer flight time (almost always longer) after the print hammer has not been actuated for a relatively long period (as long as ten minutes). In past printers, a rattle cycle has been used to minimize this problem. A rattle cycle is defined as the repeated actuation of print hammers using a current pulse that is substantially smaller than the printing current pulse. In this manner hammers move from their rest position but do not make contact with the print forms or paper. In past printers, the rattle pulse duration was the same for all hammers. The maximum allowable pulse is thus one that cannot cause any of the hammers to impact (mark) the paper in any machine. This limits the effectiveness of the rattle cycle. To minimize the morning sickness problem, the largest possible rattle cycle pulse must be applied. Data taken sometimes indicate that a rattle cycle pulse that eliminates the morning sickness problem will also cause some hammers to impact the paper.

The proposed solution is to rattle each hammer with a pulse that is proportional to the difference between the hammer's uncorrected flight time and the ideal hammer flight time. Thus, hammers that are inherently fast will receive a sho...