Panasonic Panafax UF-4000, Service Manual

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• Scanning LSI Control Signal Generation
It generates control signals for a scanning LSI (MN860741). A reduction of sub scan is
proceeded with this block.
• Scanning Data Transfer Control Circuit
The Scanning Image data (Binary or Multi-level Gray Scale) form Scanning LSI (MN860741) are
Serial. This Circuit converts the Serial Image data to the Parallel Image data, and transfers to the
Memory through DMA controller. It is used for processing the data such as masking the data,
reversing the data etc.
• Motor control
SMA7027M (IC26), which generates control pulse signals of a motor which is used for scanning
and recording.
• 2-3. Recording Data Control Block
• Reduction / Enlargement Control Circuit
This circuit is used to process the received data to fit on the recording paper, according to the
Fax Parameter Settings.
• Image Range Isolation Circuit
It identifies the halftone picture range and controls smoothing, Binary Gray Scale Conversion,
and Laser pulse width control to eliminate blocking of the recording picture which has undergone
error diffusion or other process.
• Picture Quality Correction Circuit (Smoothing)
When the receiving data (8 dot/mm x 7.7, 15.4 line/mm) is converted to 16 dot/mm x 15.4 line/
mm resolution, the current printed data and 15 surrounding printed data are sent to the
Smoothing ROM through 16 bit line and the ROM sends smoothed dot data. As a result of this
operation, the distorted curved lines are smoothed.
• Binary Gray Scale Conversion
The signal of a binary-level image such as copying is converted into a multiple-value (64-scale)
image signal for multiple-value recording.
A maximum of 5-by-5 pixels around an area is referred to in layers for conversion into multiple-
value signal.
• Laser Pulse Width Control
After smoothing, the SHINE controls Laser pulse width by the software setting of the print quality.
• Gray-Level Enhancement
This control function allows expressing higher-level scales than using a recorded signal, by
reducing line density into 1/2 or 1/3 on the original after binary-to-multiple value conversion. This
capability increases reproduction of gray scale images such as photographs.
• Synchronization Control Circuit
This circuit is used to synchronize the output of the recorded data with the horizontal
synchronizing output signal from the printer for each line.