Xerox 721P83071 用户手册

BASIC CONCEPTS

The printer contains the imaging, xerographic, and output
subsystems.  

The imaging subsystem accepts a formatted page of data from
the system controller (forms and graphics have already been
merged) for the xerographic process:

One of the important keys to LPS print quality lies in the
xerographic process itself.  The print image produced by the dry
ink is very dark to create more contrast between the printing and
the page, making images easier to read. 

The following steps describe the xerographic process: 

1. A band full of video data (1s and 0s) is transferred from the

band buffer to the laser scanner.  

2. The laser beam moves across the surface of the

photoreceptor belt based on the value of the incoming bit (1
or 0), producing a latent image.  

In this step, a charge is applied to the surface of the
photoreceptor belt.  The surface is discharged when it is
exposed to the laser beam, thus creating a pattern of dots
corresponding to the page that is to be printed.  

3. The photoreceptor belt is then exposed to dry ink.  The dry

ink clings to the pattern of dots corresponding to the page
that is to be printed. 

4. A sheet of paper traveling along the paper path is brought

into contact with the surface of the photoreceptor belt.  The
dry ink is then transferred from the photoreceptor belt onto
the paper.  

5. The paper carrying the pattern of dots passes through a

fusing mechanism that permanently affixes the dry ink to the
paper.  

6. The finished page is deposited in the output tray or bin.  The

data from that page is erased from memory.  The
photoreceptor belt is then cleaned and prepared for the next
page.  

An LPS imaging system converts a character from digitized form
into a printed image composed of tiny dots.  These dots are so
small and close together that they appear to form solid black
areas.  Image clarity is determined largely by the resolution or the
number of dots per inch printed.  Within the 4635 LPS Reference
Set, the terms spots, dots, and pixels are used interchangeably. 

The 4635 accepts 300 dots per inch (dpi) print data and images
and electronically modifies them to produce 600 dpi print
resolution.  600 dpi input print data is not accepted by the 4635
for printing.  References to 300 dpi or 600 dpi apply to both
coordinate axes (300 by 300 dpi or 600 by 600 dpi).   

XEROX 4635 LASER PRINTING SYSTEM PRODUCT REFERENCE

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