Ricoh A250 Service Manual page 692

BULLETIN NUMBER:
APPLICABLE MODEL:
GESTETNER – 3218
RICOH – AFICIO 180
SAVIN – 9918DP
SUBJECT: LOW IMAGE DENSITY
BACKGROUND:
The A250 represents one of the latest shifts in technology for Ricoh family products. An extensive market
investigation of print requirements was performed during the design phase of the A250. Market research
defined a need for an economical copier product that had increased gray scale and graphic capability due to
the market's movement toward documentation with increased usage of photographs, charts, clips, etc. The
result was the A250. The A250 is based on a printer engine technology, with certain unique print
characteristics. The A250 image output has been created to maximize the overall appearance of the
document. The A250 processes the image differently from past analog copiers, (as explained in the technical
portion of this document) and produces an image with modified features.
Since the A250 has certain unique output appearances and characteristics, it is important that Service
Technicians are educated on and made aware of the differences of the A250 so that they can properly
evaluate the output of the A250. The Service Technician should not expect or compare the output of an
analog product with the A250, using typical comparisons and black fill characteristics. The A250 uses
different parameters in image capture from analog copiers. It is important that the design criteria are kept in
mind when comparing the A250 output with that of analog products. The current test charts may not
adequately demonstrate the print quality features and benefits of the A250. The Technical Support Division
is currently investigating the possibility of creating a new test chart that highlights the improved
characteristics of the Digital Products.
Unfortunately, the A250 has been released without enough emphasis or explanation to the Service
Technician of the differences in the copy appearance. The result has been numerous concerns on the part of
Service Technicians at the time of installation. This bulletin has been created to address those concerns,
provide a better understanding of the A250 output and to correct misconceptions of the A250 output and to
further educate the Service Technician on the A250.
SYMPTOM:
1. The image density is relatively low when a sky-shot copy is made in default, Auto Exposure mode.
2. The overall image density is initially low.
DETAILED DESCRIPTIONS:
1. The Auto Exposure mode of the A250 is aimed at producing copies "true to the original". The machine will
attempt to not only reproduce the image on the original, but also any dust or other particles present on the
platen glass. In order to produce a copy true to the original, the background value used for the copy is
derived from the scanned 'white data' (or whitest area on the original). With a sky-shot copy, the machine
views any dust or particles on the contact glass as this white data (i.e. whitest areas). The value obtained
from scanning these small white areas is selected as the background density level and the black areas on
the image are then output accordingly. Therefore, with sky-shot copies, the image density of the main black
area may appear lighter than expected and white spots may be very visible (as the machine has set this
RICOH GROUP COMPANIES
TECHNICAL SERVICE BULLETIN
A250 - 001 09/21/99
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