A2.1 Signal Flow Explanation; Copy Mode - Oki OKIOFFICE44 Service Manual

A2.1 Signal Flow Explanation
Note : The OKIOFFICE 44 and OKIFAX 5000 series machines have very similar signal flows.
The differences are:
The one-line scanning processing speed of OKIFAX 5000 series is faster. The EXSEED (image
processing LSI) and SRAM (dark/light level correction data) have been added to the OKIFAX 5000
circuits.

Copy Mode

Figure A2.1.1 shows the picture signal route in local copy mode.
One-line picture data is transferred to A/D converter (analog/digital converter) 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 DRAM (line memory) via IOGA by DMA (Direct Memory Access).
Then the picture data is sent to IOGA again. Here, the picture data undergoes various kinds of picture
processings (IOGA and CPU), and is converted to two-level binary data (black and white). The one-line
binary data from IOGA is stored into DRAMs (page memory). When the data for one page has been stored
in the DRAMs, the data is read out from the DRAMs and sent to IOGA. The data is converted into a serial
data by the picture control of IOGA and transferred to the LED print head for printing as HDATA 0/1.
Writing of data into the page memory is also possible during the printing operation.
Board Descriptions A - 8 OKIOFFICE 44 Serv. Man., P/N 59276801