Star Micronics 4111 manual Rir, Print engine

An Intel 80960SA computer chip controls both the memory and the printing mechanism in the printer, called the print engine. The printer stores a whole page in RAM before printing it. (If a page is so dense that it overflows memory —amost unlikely event —the Star LaserPrinter4HI prints the page on two sheets.)

1.1.5 The Print engine

It’s the print engine that forms the actual characters and graphics. The engine directs its laser, a pinpoint stream of light pulses, through mirrors and lenses onto the surface of a positively-charged rotating drum.

r“i””r

Lens

Laser beam

Scanningmirror

ctor laserdiode

~Photosensitive drum

As the laser scans, it “draws” the page-map stored in your printer’s memory. Wherever a light pulse strikes, that tiny part of the drum drops to a neutral electrical charge. That spot then attracts fine toner powder as the drum rotates past the powder compartment.

As the drum rotates further it meets the paper. The paper itself is negatively charged by passing by a fine corona wire. Since opposite charges attract, the negative paper clings to the positive drum. Then heat and pressure from a roller melt or,fusethe dots of toner onto the paper, precisely reproducing the image.

Finally the paper slides into the output bin. The paper usually comes out face dowmso it stacks in the correct sequence.

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