OKIDATA OF1050, Service Manual

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Service Guide OF1050/2350/2450
Chapter 3 Board Description/Printer Operation
3.6 Explanation of Signal Flow for OKIFAX 1050/2350/2450
Note:
Regarding the difference of the signal flow between OKIFAX 1050 and OKIFAX 2350/2450, since
one-line scanning processing speed of OKIFAX 2350/2450 is faster in comparison with OKIFAX 1050, to
the circuit diagram of OKIFAX 2350/2450 has added the EXSEED (image processing LSI) and SRAM
(dark/light level correction data). Otherwise, the signal flow is almost the same as in OKIFAX 1050.
3.6.01 Copy Mode
Copy mode for OKIFAX 1050
Figure 3.7.1 shows the picture signal route in local copy mode for OKIFAX 1050
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.
Writing of data into the page memory is also possible during the printing operation.
Copy mode for OKIFAX 2350/2450
Figure 3.8.1 shows the picture signal route in local copy mode for OKIFAX 2350/2450
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 EXSEED (image processing LSI) and SRAM.
Here, the picture data undergoes various kinds of picture processings (EXSEED and SRAM), converted to
two-level binary data (black and white) and then sent to IOGA (scanning control). The one-line binary
picture data from IOGA is stored into P-SRAM (pseudo-SRAM). When the data for one page has been
stored in the P-SRAM, the data is read out from the P-SRAM 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.
Writing of data into the page memory is also possible during the printing operation.
3.6.02 G3 Send Mode
Figure 3.7.4 (For OKIFAX 1050)/Figure 3.8.4 (For OKIFAX 2350/2450) show the G3 send picture signal
route
In the G3 mode, the data transfer route from the scan unit up to the DRAM (for OKIFAX 1050)/ P-SRAM
(for OKIFAX 2350/2450) is the same as in the copy mode described in 3.6.01.