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DIRECT BINARY METHOD FOR DENSITY MODULATION FOR IONOGRAPHIC PRINTING

IP.com Disclosure Number: IPCOM000026114D
Original Publication Date: 1990-Jun-30
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 96K

Publishing Venue

Xerox Disclosure Journal

Abstract

In ionographic printing devices, such as that shown, for example, in US-A 4,644,373 to Sheridan, wherein a latent image is formed by imagewise modulation of a stream of ions directed towards a charge retentive surface, the final image density can be controlled by varying the amount of charge deposited in the creation of the latent image. In principle, the use of N data bits to describe each pixel in the image would allow printing 2N distinct grey levels. For example, in a 2 bit per pixel system, each pixel could be one of four levels. It is also known that the size of the modulation or control nib area has a positive effect on the modulation of the ion throughput.

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XEROX DISCLOSURE JOURNAL

DIRECT BINARY METHOD FOR DENSITY MODULATION FOR U.S. C1.346/158 IONOGRAPHIC PRINTING
Frank C. Genovese

Proposed Classification

Int. C1. Gold 15/06

Nib

Fig. I

0 LSB J

MSB 0

LSB 0 B

Fig. 2A

Fig. 25

MSB

1 TC

B

\ 1 A

C' Fig. 2D

Fig. 2C

XEROX DISCLOSURE JOURNAL - Vol. 15, No. 3 May/June 1990 141

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DIRECT BINARY METHOD FOR DENSITY MODULATION FOR IONOGRAPHIC PRINTING(Cont'd)

In ionographic printing devices, such as that shown, for example, in US-A 4,644,373 to Sheridan, wherein a latent image is formed by imagewise modulation of a stream of ions directed towards a charge retentive surface, the final image density can be controlled by varying the amount of charge deposited in the creation of the latent image. In principle, the use of N data bits to describe each pixel in the image would allow printing 2N distinct grey levels. For example, in a 2 bit per pixel system, each pixel could be one of four levels. It is also known that the size of the modulation or control nib area has a positive effect on the modulation of the ion throughput.

In accordance with Figure 1, if the data bits are distributed and control two output FET's for each nib, each nib may be used to generate the four analog voltages required. In such an arrangement, the available nib area is divided into two segments, corresponding to the most significant bit and the least significant bit of the 2 bit per pixel value....