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SYSTEM LAYOUT
Safety Features
The machine has the following countermeasures to prevent overheating.
1. 1st protection device: Hardware cuts off when the machine temperature gets to
207 C
2. 2nd protection device: Software cuts off when the machine temperature gets to
220 C for 3 seconds
3. 3rd protection device: Thermostat measures the temperature of the hot roller
and cuts off main power to the fusing lamp when the temperature gets to a pre-
determined level.
Safety Devices
1. Fusing power gets cut off when the front cover is opened.
2. LSU power gets cut off when the front cover is opened.
The temperature of the fusing units cover surface stays at less than 80ºC. This
protects the user. A caution label is attached where the customer can see it easily
when the rear cover is opened
6.3.5 LASER SCANNNING UNIT (LSU)
The LSU converts video data into an electrostatic latent image on the surface of
the OPC drum. This gets done by controlling the laser beam and exposing the
surface of the OPC drum to the laser light. A rotating polygon mirror reflects the
laser light onto the OPC drum. Each side of the mirror is one scan line.
The OPC drum turns as the paper feeds to scan the image down the page. A
/HSYNC signal gets created when the laser beam from LSU gets to the end of the
polygon mirror. Then the signal goes to the controller. The controller detects the
/HSYNC signal to adjust the vertical line of the image on paper. In other words after
the /HSYNC signal gets detected, the image goes to the LSU to adjust the left
margin on the paper.
6-10
20 July 2005
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