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Mixed Character Density Column Number Control Logic

IP.com Disclosure Number: IPCOM000051629D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 32K

Publishing Venue

IBM

Related People

Currin, AK: AUTHOR [+2]

Abstract

With wire matrix or character composition printers, it is often desira to mix printed character densities or sizes within a given print line. This may be done to create the effects of italicization or bold face, large upper case, smaller lower case, etc. In a specific printer of this sort, two printed character densities may be offered nominally at 10 characters per inch or 16.66 characters per inch.

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Mixed Character Density Column Number Control Logic

With wire matrix or character composition printers, it is often desira to mix printed character densities or sizes within a given print line. This may be done to create the effects of italicization or bold face, large upper case, smaller lower case, etc. In a specific printer of this sort, two printed character densities may be offered nominally at 10 characters per inch or 16.66 characters per inch.

A problem occurs when both character densities are permitted to exist within the same printed line. At 10 characters per inch, the width of a given character is approximately 0.1" and with 16.66 characters per inch, the width of a character is .06". At some arbitrary character column location along a printed form when printing is occurring at 10 characters per inch, a change in character density to
16.66 characters per inch for the next character may cause it to be printed all or partially within the field of a previous printing at 10 characters per inch. This creates an over-printing problem which is to be avoided. The correct column for printing the next character at a new print density can be generalized by an algorithm as follows: The next column number is equal to: See Original. (1).

In Equation (1) for this algorithm, the "ceiling" means rounding up to the next larger integer. For example, if printing is occurring at column 3 at 10 characters per inch and it is desired to change the character density to 16.66 characters per inch, the next column number be defined by the algorithm as follows: Next Col. No.= Ceiling (2x.1 over .06) 1=Ceiling (3.33) 1=5 (2).

As may be seen, multiplication and dividing functions are required, but these instructions and capabilities are not usually provided by subroutines in microprocessors of the sort employed for controlling printers.

This article describes the use of a table look-up calculation procedure in conjunction with the specific logic circuits for implementing these processes.

A hardware embodiment of the logic circuits is shown in Fig. 1, and conversion tables are shown in Fig. 2. Referring to Fig. 2, the current column number, that is, the last column number passed plus 1 is loaded into a register 1. The output of the register is connected to an address bus for a read-only storage (ROS) unit 2 associated with the microprocessor being utilized to control the printer. The read-only storage is accessed by this address and the co...