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Grating Position Up/Down Counter Controller

IP.com Disclosure Number: IPCOM000081000D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Carmichael, JM: AUTHOR [+2]

Abstract

This up/down counter controller is capable of tracking position grating transitions under all conditions of mechanical vibration and printer head carrier turnaround in an ink jet printer. In such a printer, a photographic film grating may be used for scan placement and for head carrier position information. The correct counting of this grating is critical to the operation of the control logic of the printer.

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Grating Position Up/Down Counter Controller

This up/down counter controller is capable of tracking position grating transitions under all conditions of mechanical vibration and printer head carrier turnaround in an ink jet printer. In such a printer, a photographic film grating may be used for scan placement and for head carrier position information. The correct counting of this grating is critical to the operation of the control logic of the printer.

The carrier position is derived by using a two-phase grating so that the direction of the carrier can be determined, as well as counting of individual grating lines. An up/down counter 1 is used to count the grating pulses, but a controller 2 is also used to indicate to counter 1 the direction of the count and to supply the actual count pulses.

There are two critical conditions that controller 2 is required to handle.

1) The head carrier can come to rest on the edge of a grating

line; mechanical vibrations at this point can cause

grating transitions. Controller 2 is able to track these

transitions.

2) The head carrier can change direction at any point along

the two-phased grating. Controller 2 must decide quickly

which direction the carrier is travelling and update the

counter 1 correctly.

Anticipation logic, which resolves both of the above conditions, is provided in controller 2 as illustrated in Figs. 2-4, with various control signals shown in Figs. 5 and 6. Description of this logic follows:
1. Within a cycle of...