SBU: Sensor Board Unit
Converts the image reflected from the front side of the originals into digital image signals, then transmits them to the BICU.
CIS: Contact Image Sensor
Converts the image reflected from the back side of the originals into digital image signals, then transmits them to the BICU.
Characteristic Value Memorization
SBU characteristics are stored in the BICU. These characteristic values need adjustment when the lens block is replaced.
- SP4-008-001 (Sub Scan Magnification Adj)
- SP4-010-001 (Sub Scan Registration Adj)
- SP4-011-001 (Main Scan Reg)
- SP4-688-002 (Scan Image Density Adjustment)
Preventing Dirty Background for DF Scanning
The scanned density difference between ADF and Book scanning can be adjusted with SP4-688-002 (Scan Image Density Adjustment). Adjusting the scanned density difference prevents image problems such as dirty background.
Test Mode
SP4-699-001 generates a VPU test pattern as a diagnostic tool for SBU malfunctions. Press [Start] after selecting the VPU test pattern in SP4-699-001. The VPU test pattern is output. The SBU state can be checked with the output image.
SP4-699-001 (SBU Test Pattern Change)
| Setting Value | Description |
|---|---|
| 0 (default) | Image output |
| 1 | Test pattern output / Fixed-value output (682-digit) |
| 2 | Test pattern output / Horizontal gradation pattern (10-bit tone, 2-dots/step) |
| 3 | Test pattern output / Vertical gradation pattern (10-bit tone, 2-lines/step) |
| 4 | Test pattern output / Grid pattern (20mm x 10mm Grid pattern) |
BICU Function Outline
- Scanner Data Processing
An ASIC on the BICU performs scanner processing, including black level correction, white level correction, and gray balance correction. The ASIC on the BICU also has AE (automatic exposure control) function. - Converts image signals from the SBU and CIS into various types of image, and outputs them to the controller (memory) via a PCI bus.
- Receives image signals from the controller (memory) via a PCI bus, and converts them into images to output to the LDB.
- Outputs the sheet-through ADF control signal.
- Relays various types of signals and power sources.
Image Processing Outline
In the BICU, digital image signals that are transmitted from the SBU pass through processes such as shading correction, line-to-line adjustment, and other image processing. Then image data is converted into digital signals (2-bits/pixel, or 4-bits/pixel) and sent to the printer unit. (For details about image data flow, see Block Diagram)