Browse Prior Art Database

Single Sensor for Carrier Homing and Print Wheel Identification

IP.com Disclosure Number: IPCOM000045662D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Quinn, PA: AUTHOR

Abstract

In daisy wheel typewriters, it is advantageous to electronically detect the identity of the print wheel installed on the print carrier and also to be able to determine the home position of the carrier accurately. A technique for accomplishing those two functions is illustrated above. Where the print wheel is installed using a print wheel cartridge, the print wheel cartridge may be coded by forming three holes or any combination of the three into the cartridge to form a binary code identification for the print element. These three holes 10 are formed in the lower part of cartridge 12 which contains print wheel 14. The holes 10 may be placed proximate to a predefined region 16 which may be utilized for print carrier homing.

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Single Sensor for Carrier Homing and Print Wheel Identification

In daisy wheel typewriters, it is advantageous to electronically detect the identity of the print wheel installed on the print carrier and also to be able to determine the home position of the carrier accurately. A technique for accomplishing those two functions is illustrated above. Where the print wheel is installed using a print wheel cartridge, the print wheel cartridge may be coded by forming three holes or any combination of the three into the cartridge to form a binary code identification for the print element.

These three holes 10 are formed in the lower part of cartridge 12 which contains print wheel 14. The holes 10 may be placed proximate to a predefined region 16 which may be utilized for print carrier homing.

On the typewriter frame, a microswitch or other suitable switching device 18 is mounted such that, as the carrier moves, it will engage the switch 18. During the carrier homing routine, the carrier is typically moved away from the switch 18 and it is then moved back toward the switch in the direction of the arrow until such time as the switch follower 20 engages cartridge 12 and makes the switch 18, thereby homing the carrier. After the carrier is homed, the precise position of the carrier is then known and the carrier may be incremented further in the direction of the arrow until it is positioned appropriately for sensing the holes 10. As each sensing cycle occurs, a particular pos...