Browse Prior Art Database

Toner Concentration Control

IP.com Disclosure Number: IPCOM000087985D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Smith, GL: AUTHOR

Abstract

This is a toner concentration control technique for a document copier which is an alternative to that disclosed in IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, p. 1258. The feed rate of toner into the developer unit is controlled by comparing the reflectance of a nonconductive area on the drum seal or on the photoconductor with a reference level.

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Toner Concentration Control

This is a toner concentration control technique for a document copier which is an alternative to that disclosed in IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, p. 1258. The feed rate of toner into the developer unit is controlled by comparing the reflectance of a nonconductive area on the drum seal or on the photoconductor with a reference level.

Photoconductor drum 1 has a photoreceptive material la wound thereon for imaging and developing electrostatic images. Drum seal 2 has nonconductive patch 3 positioned as shown. If desired, patch 3 can be located on the photoconductor surface. The patch may be made from photoconductive material.

In operation, patch 3 is charged and toner is deposited on the patch by developer 10 as drum 1 rotates in the direction of arrow 11. The developed patch is thereafter illuminated by light source 12 and the reflected light is detected by photosensor 13.

Compare circuit 15 is responsive to the signal supplied by photosensor 13 to compare the sensed signal to a reference and provide an output to the replenisher motor 16 when the toner concentration is low. Motor 16 causes toner dispensing wheel 17 to rotate thereby effecting the addition of toner to the developer mix. Since the toner concentration is inversely related to the reflectance of the patch, a high reflectance indicates to the comparator the need to add toner.

Continued rotation of drum 1 causes patch 3 to move through a clea...