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Adaptive Control of Print Hammers

IP.com Disclosure Number: IPCOM000060962D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Anderson, LL: AUTHOR [+3]

Abstract

Using a single shared impact sensor for the platen, together with individual impact sensors on the return springs of each of the print hammers, economically provides a line printer with the impact information for continuously adapting a drive energization program for each hammer. Fig. 1 shows shared force sensor 1 on platen 2. This is a global sensor used to control the compensation of variations on the coil temperature, paper thickness, etc. Fig. 1 also shows a representative force sensor 3 at the return spring 4. This is a local sensor for each hammer 5; it provides dynamic displacement information for the related hammer. Fig. 1 also shows length and motion ratios of the hammer. The return spring elongation WX1 can be obtained by F = k WX1, where F is the force applied to the sensor and k is the spring constant.

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Adaptive Control of Print Hammers

Using a single shared impact sensor for the platen, together with individual impact sensors on the return springs of each of the print hammers, economically provides a line printer with the impact information for continuously adapting a drive energization program for each hammer. Fig. 1 shows shared force sensor 1 on platen 2. This is a global sensor used to control the compensation of variations on the coil temperature, paper thickness, etc. Fig. 1 also shows a representative force sensor 3 at the return spring 4. This is a local sensor for each hammer 5; it provides dynamic displacement information for the related hammer. Fig. 1 also shows length and motion ratios of the hammer. The return spring elongation WX1 can be obtained by F = k WX1, where F is the force applied to the sensor and k is the spring constant. The hammer displacement can be computed from WX2 = WX1 (L2/L1). The hammer displacement is used to modulate the pulse width of a coil driver 6 in order to control the flight time variation of the hammer 5. All the local sensors can be calibrated by the global sensor. Fig. 2 shows how individual sensors (local) can be batch fabricated by using PVF2 strip 7, upon which are deposited aluminum contacts 8. Fig. 3 shows the driver. Switching control between current signal I and force signal F at switch 9 provides a very accurate hammer trajectory control and automatically compensates for temperature variation.

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