Browse Prior Art Database

Optical Toner Low Algorithm

IP.com Disclosure Number: IPCOM000101529D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Beck, JL: AUTHOR [+3]

Abstract

Disclosed is an algorithmic process to detect a low level of toner remaining in a developer using an optical sensor system. The system includes an LED light source and photodetector that 'sees' through a transparent region of the developer housing. The interior walls of the developer in the area of the sensor are wiped once every 13 seconds by a flexible scraper mounted to a paddle. The wiping action cleans the interior walls so that the light from the LED is transmitted to the photosensor when there is no toner in the region between the cleaned walls.

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Optical Toner Low Algorithm

       Disclosed is an algorithmic process to detect a low level
of toner remaining in a developer using an optical sensor system.
The system includes an LED light source and photodetector that 'sees'
through a transparent region of the developer housing.  The interior
walls of the developer in the area of the sensor are wiped once every
13 seconds by a flexible scraper mounted to a paddle.  The wiping
action cleans the interior walls so that the light from the LED is
transmitted to the photosensor when there is no toner in the region
between the cleaned walls.

      The problem addressed by the algorithm disclosed is the proper
interpretation of information from the sensor.  The space between the
photodetector and the LED can be scraped free of toner even while as
much as a third of the original toner remains in the developer.  It
is necessary to delay interpreting this clear space as a low toner
condition at least until only 10% of the original toner charge
remains.

      The solution is to examine the length of time during the
scraping operation that the sensor is blocked.  As the scraper
revolves on the paddle, it will push a column of toner before it,
even when only a small amount of toner is left.  Only for very low
toner levels will the width of this toner column approach zero,
causing the time the sensor is blocked to approach a minimum.  It is
this condition which is interpreted as 'toner low'.

      The algori...