Oki OKIOFFICE 84 Service Manual page 368

Page: 215
Service Guide OKIOFFICE 84
Chapter A Board Descriptions
Copy Mode
Figure A2.1 shows the picture signal route in local copy mode.
One-line picture data is transferred to A/D converter (analog/digital) via operational amplifier from the scanning unit
(CIS: contact image sensor) as an analog data. After conversion from analog data to 6-bit digital data by A/D
converter, the picture data is sent to IEXSEED (image processing LSI) and SRAM. Here, the picture data undergoes
various kinds of picture processings (IEXSEED and SRAM), converted to two-level binary data (black and white) and
then sent to IOGA4 (scanning control). The one-line binary picture data from IOGA4 is stored into DRAM. When the
data for one page has been stored in the DRAM, the data is read out from the DRAM and sent to IOGA4. The data is
converted into a serial data by the picture control of IOGA4 and transferred to the LED print head for printing as
HDATA0. Writing of data into the page memory is also possible during the printing operation.
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