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Drop Spacing in Ink Jet Printers using a CCD Linear Array

IP.com Disclosure Number: IPCOM000089544D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Flurry, GA: AUTHOR

Abstract

In ink jet printers drop-to-drop spacing of the drops are conventionally determined by examining the result of the ink stream, the measurements usually looking at stream velocity, deflection height, etc. However, drop-to-drop spacing may be measured directly, utilizing the arrangement shown in Figs. 1 and 2.

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Drop Spacing in Ink Jet Printers using a CCD Linear Array

In ink jet printers drop-to-drop spacing of the drops are conventionally determined by examining the result of the ink stream, the measurements usually looking at stream velocity, deflection height, etc. However, drop-to-drop spacing may be measured directly, utilizing the arrangement shown in Figs. 1 and 2.

For example, in Fig. 1, a light-emitting diode (LED) 10 is located adjacent one of the deflection electrodes sidewall 11, and a lens 12 is placed adjacent the other electrode's sidewall 13 in a spaced-apart arrangement through which the ink stream 14 passes. A charge-coupled device (CCD) array 15 is positioned on the opposite side of the lens to receive and store the information necessary to determine the drop-to drop spacing. The arrangement is such that when the LED 10 is fired at the drop generation rate, the image of the stream over N Lambda(drop-to-drop spacing) is stored in the CCD by optical integration (Fig. 2).

If a processor (not shown) is connected to the CCD, the image of the stream can be shifted out of the CCD and into a threshold circuit which outputs a logical 1 for a CCD cell covered by a drop, and outputs a logical zero for a cell not covered by a drop. The processor may check cell output as it is shifted out of the array. A string of covered cells indicates a drop has been found, and (N + 1) drops are shifted out of the array. The processor then compares the number (K) of cells betwe...