Gestetner G060 Service Manual page 966

BULLETIN NUMBER:
APPLICABLE MODEL:
GESTETNER – DSC38/DSC38S
RICOH – AP3800C/AP3800CMF
SAVIN – SLP38C/SLP38CS
SUBJECT: "IMAGE COVERAGE" vs "PIXEL COVERAGE" RATIO
GENERAL:
This Technical Service Bulletin has been issued to:
1) replace the term "image coverage ratio" with "pixel coverage ratio," so as to clear up any
misunderstandings, and to
2) clarify the differences between SP7-833 and SP7-908
NOTE: SP7-908-1 thru 8 has been applied to the G060 from March '02 production, and both SP7-833
and 908 have been applied on the G082 from the first mass production run. Also, SP7-908-5
thru 8 contains the same data as SP7-833-11 thru 14.
1. Terminology: Replacing "image coverage" with "pixel coverage ratio"
The original meaning of "image coverage" is simply the percent of pixels being used to write the image.
However, since this refers only to the print data itself, and not the final image on the output, a more clear
term is the "pixel coverage ratio."
The machine keeps track of two types of pixel coverage ratios:
1) The ratio for the most recently printed page
2) The average ratio for all pages printed up to the present
Calculation method for both #1 and 2 above:
# Pixels used for image areas / Total pixel area of 1-full pg. (corresponding paper size)
NOTE:
1. To calculate #2 above, the machine keeps a cumulative count for these 2 values.
2. The pixel coverage ratio only refers to the percent of pixels to be used for image writing in the data itself,
not the finished product (output). It is not directly proportional to the amount of toner consumed, and can
therefore not be used to calculate toner consumption.
The amount of toner actually consumed (i.e. used on the output) also depends on factors such as the:
! Type of image (solid, text, or lines):
The "edge effect", a general side effect of the development process whereby extra toner is
attracted to the edges of images, i.e. becoming slightly darker. Of course images
containing more edges will show this effect more prominently.
! Toner concentration
! Development capability
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Copyright 2003 RICOH Corporation. All rights reserved.
TECHNICAL SERVICE BULLETIN
G060/G570 – 027 03/19/2003
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