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Hammer Check Identification

IP.com Disclosure Number: IPCOM000089936D
Original Publication Date: 1968-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Schappe, TL: AUTHOR

Abstract

In previous checking systems for a printer, a number of check planes of cores with one core for each print position are used for checking the operation of the print hammers. For example, a Print Line Complete PLC plane is used to determine that printing occurs in each addressed position, the PLC bit being off in each position at the beginning of a line and a bit being set for each position when a Compare signal occurs. An Equal Check EC bit is set in an EC core plane each time a Compare occurs and is reset the next time the print position is addressed. An Equal Check Delay ECD bit is set in an ECD plane when the corresponding EC bit is reset and is reset the next time the print position is addressed.

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Hammer Check Identification

In previous checking systems for a printer, a number of check planes of cores with one core for each print position are used for checking the operation of the print hammers. For example, a Print Line Complete PLC plane is used to determine that printing occurs in each addressed position, the PLC bit being off in each position at the beginning of a line and a bit being set for each position when a Compare signal occurs. An Equal Check EC bit is set in an EC core plane each time a Compare occurs and is reset the next time the print position is addressed. An Equal Check Delay ECD bit is set in an ECD plane when the corresponding EC bit is reset and is reset the next time the print position is addressed. A Hammer Fire signal is compared with the EC and ECD bits for each position to determine if the hammer driver operates correctly. A Print Check PC bit is set in a PC plane whenever a hammer check is detected.

In the previous arrangements, the PC bit indicates where the error occurs but does not indicate what the type of error is. These same check bits or their equivalents can, however, be used to identify the type of error. For example, by using And 10 which is set by Not Print Compare and Not Hammer Driver HD Off signals to set bits in the PLC and C2 ECD planes through Or's 20 and 23, the condition of a hammer firing erroneously is identified by this combination of bits. By using And 12 which is set by Last Scan and No Compare signals to...