Sharp UX-B700 Service Manual page 65

1 Serial data reception
2 Main scan resolution conversion
3 Sub scan resolution conversion
4 Main scan print position centering
5 Swath data conversion
6 Printing dot calculation
7 Split printing for power protection
8 Transmission of printing data/delivery command
9 Command transmission
10 Response reception
Main functional block
Relevant functional block
1) Overall data conversion controller
It controls a data flow of the overall ASIC. When data is stored in the
203.2 dpi data buffer, the controller activates the main scanning direc-
tion resolution conversion circuit of the subsequent stage, etc. and stores
the data in the main scan 600 dpi data buffer. Then activates the sub
scanning direction resolution switcher circuit and stores the converted
data in the sub scan 600 dpi data buffer. When the data of more than
208 lines is ready for print head vertical direction, triggers are sent to the
swath conversion circuit and the ESC command adding circuit.
2) Serial data receiving circuit
This circuit receives serial printing data from Fax Engine and stores
them in the 203 dpi data buffer. Data PDAT is received via an 8-bit shift
register when PCLK starts up. The circuit writes the data on the buffer
every 8 dots (1 byte).
The input amount per line is fixed to 216 bytes (1728 dots). The upper
limit of the serial transfer frequency is set to 3.3 MHz. Equipped with the
following functions to realize main scanning direction centering.
• Received data destruction
This function does not receive (invalidates) the data printed on both
margins, unnecessary for centering, and only accepts valid data. The
number of dots to invalidate depends on the conversion rate of resolu-
tion.
If the number is less than 0, data will not be invalidated and white dots
will be inserted instead.
• Interpolation of blank data (8 dots or less) on both margins
Blank data of a byte (8 dots) are inserted in the after-mentioned blank
data interpolation circuit. Blank data of less than 1 byte are inserted in
the main block.
The per-line-data to be written on the 203.2 dpi data buffer should be
218 bytes at the maximum.
Functional block
Function
Table 1. Correlation of ASIC functions and functional blocks
3) 203 dpi data buffer (FIFO controller)
It occupies 96 kB of DRAM memory as a serial data receiving buffer.
The buffer mounts an address counter as part of FIFO mechanism.
Equipped with a judging circuit to indicate the FIFO status either as FULL,
Near FULL or EMPTY.
4) Main scanning direction resolution conversion circuit
This circuit reads raster data from the 203 dpi data buffer and changes
the resolution by the dot. The converted data will be stored in the main
scan 600 dpi data buffer one by one.
After converting 4800 dots (600 bytes) in the main scanning direction,
end-of-line pulse will be sent.
Equipped with the following functions to realize main scanning direction
centering.
• Interpolation of 8-dot (byte) blank data
This function inserts blank data on both ends of the line for main scan-
ning direction centering. It depends on the conversion rate of resolu-
tion.
If the number of dots is less than 0, blank data will not be interpolated.
The blank data of less then 8 dots will be inserted in the aforemen-
tioned "serial data receiving circuit". The main block accepts the inser-
tion of byte size (8-dot) blank data.
5) Main scan 600 dpi data buffer (FIFO controller)
It makes up the buffer with a FIFO mechanism. Though it carries out the
same pointer control as the 203 dpi data buffer, The data byte per line is
fixed to 600.
The Read channel should be connected to the sub scanning direction
resolution conversion circuit.
5 – 10
UX-B700U
FO-B1600U