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Operation, function, and processing of ICU IMAGE PWB section

  Section

Operation, function, and processing

Unit or device

IMG ICU
PWB

Input
processing

Input
processing

Refer to gamma table

Refers to gamma tables separate from
each the image quality mode and
density level (SIM46-10 to 19, 20, 1,
2). Converts the scanned image to
gamma characteristics for the the
image quality mode and density level.

Input
processing
ASIC

SRAM

Color conversion
(R, G, B 

→

 Y, M, C)

CPU
CPU C

Monochrome creation
(monochrome mode)

For the monochrome mode, the
magenta image data in the color
image data is substituted for the
monochrome signal.

Scanner
ASIC

Histogram processing

For the monochrome mode, the entire
image is scanned and the data for
each pixel is collected and histogram
processing is performed.

Generates self-print data

Area
separation

Determine
type of
image (text,
photo,
shading)

Black text edge judgment

Picks up the contrast at the image
edges and judges whether they are
text edges or not. Edges that are
judged as text edges are then judged
whether they are monochrome or color.

CPU

Area
separation
ASIC A

Shading judgment

Judges whether the image is based on
shading or gradations (judges printed
image)

CPU C

Area
separation
ASIC B

Photo judgment

Overall judgment (images that are not
judged as text or shadings are judged
as photo images)

Area
separation
ASIC D

Area
separation
ASIC C

Black
generation

Generate
black
component

The black component for the color
mode is generated from the Y, M, and
C components

Black
generating
ASIC
CPU
CPU C

Color
correction

Corrects the
Y, M, C, and
K color
component
balance

Refers to regulation lookup tables for
each of the input colors (C, Y, M, and
K), and corrects the C, Y, M, and K
color levels so that the print output is
close to the color of the original

Color
correction
ASIC (Y, M,
C, and K)

ROM

CPU
CPU C

Zooming

Zooms in on image in the main
scanning direction

Color
correction
ASIC

SRAM

CPU
CPU C

Filter
processing

Image MTF correction

Using the filtering table, performs
filtering according to the area
separation results

Color
correction
ASIC
CPU

Intermediate
adjustments

Gamma
correction
(dither
patterns)

Linearity correction is performed by
dither patterns using the gamma
characteristics of the printer engine

CPU C
Interm
ediate
adjustment
ASIC

Image output
timing
adjustment

Adjusts the output timing for the color
tables of each Y, M, C, and K

CPT pattern
output

Outputs CPT print pattern data in
yellow color

Self-print
data
generation

AR-C150

2 – 15

Gamma is changed by the picture quality adjustment with the special
functions of the picture quality mode and the density level.

R, G, B, color signals are converted into Y, M, C color signals.

Yellow image

Mazenta image

Cyan image

TEXT / PHOTO, PHOTO,PRINT PHOTO(COLOR MODE)

1

1.5

2

2.5

3

3.5

4

4.5

5

OUTPUT

INPUT

TEXT(COLOR MODE)

1

1.5

2

2.5

3

3.5

4

4.5

5

OUTPUT

INPUT

MAP(COLOR MODE)

1

1.5

2

2.5

3

3.5

4

4.5

5

1

1.5

2

2.5

3

3.5

4

4.5

5

OUTPUT

INPUT

AR-C150

2 – 16

The type of document images in each area is judged from
The density difference (contrast), run length, and the number of use
are analyzed to judge the type of images (dot image, black character
image, photo image). 

Black components are formed from Y, M, C color components. Some
of Y, M, C components of an image are extracted from Y, M, C color
components as the black image component.
The extracted components (which are formed to black components)
are subtracted from the color components of Y, M, C. 
If each component of Y, M, C is virtually equal to each other, all are
treated as black components.

Black image

Filter process is performed separately for each area according to the
result of area separation.
The text area is subjected to the Sharp filter process to improve clar-
ity, On the other hand, the dot area and the photo area are subjected
to the soft filter process. The gradation of the photo area is expressed
smoothly.

Vague image

Contrast image

The dot area is subjected to the soft filter process to reduce the moire
phenomenon.

Correction is performed according to the gamma adjusted by the
color balance (gamma) adjustment (SIM 46-24, 22 or 21). 

Dot pattern

Large

Small

Runlength (large)

Dot pattern

Runlength

Runlength (small)

Complicated

C

M

Y

Bk

C

M

Y

Bk

C

M

Y

Bk

C

M

Y

Bk

C

M

Y

Bk

Color image (Color text, Photo, Dot pattern image)

Black color text

Original

Before (No filter)

After (soft filter)

Reduced moire

Output density

Input density

Laser diode ON duty

Standard (Target)

g

Adjusted 

g

AR-C150

2 – 17

Operation, function, and processing of ICU MAIN PWB section

Section

Operation, function, and processing

Unit or device

ICU MAIN
PWB

Output
processing

Converts data to
laser power

Converts the Y, M, C, and K color data to laser
power signal

LSU ASIC

Outputs the exposure level (laser power) according
to the density and gradation levels (converts 8-bit
data to laser ON-duty)

CPU

PWM controller

Voltage - frequency conversion (controls frequency
and controls magnification in main scanning
direction)

CPU C

VCO

Delays the image data signal by the amount the
position of the photosensitive drum is shifted

Tandem memory

Controls the dot pitch (matches the dot positions in
the main scanning direction for each color)

Synchronous IC

Outputs the laser beam signal

Driver (differential IC)

Original images are processed as follows according to the result of area separation and printed out.

Copy mode and image processing

Model

Image processing

Input gamma

(table)

Area

separation

Color correction (table)

Filter processing (table)

NOTE

Color

Text/photo
mode

AR-C100/150 Text/photo

mode

Yes

Text/photo mode

Text/photo mode filter
(strong)

Text mode

AR-C150

Text/photo
mode

Yes

Text/photo mode

Black text emphasis filter
(strong)

Printing photo
mode

AR-C150

Text/photo
mode

—

Text/photo mode

Smoothing filter (whole
surface) (Weak)

Gamma is moderate and
filter is smoothing filter
(Moire deterrent)

Photographic
paper photo
mode

AR-C100/150 Photographic

paper photo
mode

—

Photographic paper
photo mode

Photographic paper
photo mode filter (weak)

Mapping mode

AR-C150

Mapping mode

—

Text/photo mode

Mix filter (strong for text
and weak for shading)
(Intermediate strength)

Gamma is raised and
filter alleviates Moire and
emphasizes

Monochrome

Text/photo
mode

Manual

AR-C100/150 Text/photo

mode

Yes

—

Text/photo mode filter
(strong)

Auto

Auto mode

Yes

—

Text mode

Manual

AR-C150

Text mode

Yes

—

Black text emphasis filter
(strong)

Auto

Text/photo
mode

Yes

—

Printing photo
mode

AR-C150

Printing photo
mode

—

—

Smoothing filter (whole
surface) (Weak)

Photographic
paper photo
mode

AR-C100/150 Photographic

paper photo
mode

—

—

Photographic paper
photo mode filter (weak)

Mapping mode

AR-C100/150 Mapping mode

—

—

Mix filter (strong for text
and weak for shading)
(Intermediate strength)

Original (Color)

Text

Text (black)

Text (color)

Dot pattern

Black color
create

Filter process

Priority

Solid black

Black color
control

Strong/Sharp

Soft

Resolution

Tone

Photo

Mono color dot 
pattern

Color dot pattern

AR-C150

2 – 18