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Programmable Hammer Addressing for a Line Printer

IP.com Disclosure Number: IPCOM000041268D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Carrington, JE: AUTHOR [+3]

Abstract

The print controls of a line printer are provided with a programmable memory for storing a table of hammer addresses which can be changed if the hammer driver addresses are changed without changing the address circuitry. The print controls for a line printer include a Hammer Address Buffer (HAB) 10 to be addressed simultaneously with the Print Line Buffer (PLB) 11, the Check Buffer (CKB) 12, and the Band Image Buffer (BIB) 13. PLB 11 is a read/write memory which is loaded with data to be printed at various print positions of a print line. HAB 10 is likewise a read/write memory which is loaded by a microprocessor with a Hammer Address Table (HAT) consisting of the addresses for the hammers corresponding to the print positions of the print line.

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Programmable Hammer Addressing for a Line Printer

The print controls of a line printer are provided with a programmable memory for storing a table of hammer addresses which can be changed if the hammer driver addresses are changed without changing the address circuitry. The print controls for a line printer include a Hammer Address Buffer (HAB) 10 to be addressed simultaneously with the Print Line Buffer (PLB) 11, the Check Buffer (CKB) 12, and the Band Image Buffer (BIB) 13. PLB 11 is a read/write memory which is loaded with data to be printed at various print positions of a print line. HAB 10 is likewise a read/write memory which is loaded by a microprocessor with a Hammer Address Table (HAT) consisting of the addresses for the hammers corresponding to the print positions of the print line. BIB 13 is a read/write memory loaded with character data in the order in which characters are arranged on a type board. BIB 13 and PLB 11 are accessed simultaneously by BIB address ADDR and PLB address ADDR logic for comparison by compare circuit
14. If the character data and print data coincide, an EQUAL signal is generated which produces an INITIATE FIRE signal. HAB 10 is accessed in parallel with PLB 11 (Fig. 1) and the proper address is read from HAT and sent to the hammer driver cards. The final card select and hammer select is performed on the hammer driver card as seen from the partial schematic of a hammer driver card of Fig. 2 and the memory map of Fig. 3. The arran...