29 June 2017
Introduction
The printer works fine except the letters are blurring and sometimes, there are horizontal lines and vertical lines. Replacing and cleaning up the printing cartridge will improve the printing in some areas but not the blurring lettering, horizontal and/or vertical lines. This article will try to solve this problem
What could be wrong?
If the printer is still new and there is nothing wrong with the Lasing Scanning Unit (LSU), most likely the lens of the LSU is dirty and require cleaning.
What is LSU?
It is the “printer head” of the printer. Instead of emitting ink, the LSU emits a laser beam, directing it at the drum of the toner cartridge so that electrostatic charge can be transferred onto the paper to form a “temporary glue” to pick up the carbons as the paper passes through the drum.
Why need to clean the unit?
When we move our printer around with toner cartridge still inside or when we remove and install the cartridge without taking necessary precaution, some toner powder could have fallen on to the lens of the LSU. This will weaken the laser beam and prevent electrostatic charge being transferred onto the paper; as a result, the printing either got missing characters or blank horizontal or vertical lines.
Where is this LSU unit located?
For ML-2160, the LSU unit is hidden from view and it is located just under the black plastic cover at the opening where we install or replace the toner cartridge as shown in attached. The lens is a curvy clear plastic of about 100 mm x 6 mm.
Can Clean the Lens Without Dismantling the printer?
One may be lucky to use proper tool such as the dentist's mirror to check the lens and make attempts to clean the lens, first using cotton stick to get rid of the dirt; then using anti-static cloth to pick the lint left by the cotton wool. There is never any harm done provided the cleaning is done carefully, without using any chemical or solvent that will damage or scratch the surface of the lens.
What’s Required to Strip the Printer?
Should there be a need to dismantle the printer, one would need the following tools
a) A small watch screw driver to ply open the casing
b) A Philip screw driver the unscrew some of the cross screws
How to Dismantle?
There are only 5 detachable panels on the printer and they are held to each other and to the printer frame by plastic clips and a few screws.
1. Start working from the side panel. First unscrew the only screw that is securing the right panel to the printer frame.
2. Place the printer upside down and unclip the bottom of the side panel from the printer frame and work towards to top of printer to release other clips by plying open the panel edges carefully with the small screw driver.
3. Unscrew the back and the front panel and remove them. Noting that the front panel is clipped onto the top panel and will need to unclip using the small screw driver
4. Once the front panel is removed, one should see the LSU from the front and also the 2 screws holding the black plastic to the printer frame. Remove them to free the black plastic so that one can unscrew the 3 screws, securing the LSU.
5. At this point, it is good to mark the exact position of the LSU so that one could fix the unit back into its exact position during assembling.
6. Clean the lens cotton wool and remove any lint left over using anti-static clothing.
7. Test the printing before re-assemble back the panels etc.
How to Prevent Dirtying the Lens?
ML-2160 was designed having the LSU placed directly underneath the toner cartridge. This has the disadvantage for lose toner to drop or deposit on the lens easily. It is therefore essential to always remember to put a clean paper to cover up the lens when removing the toner cartridge for inspection or replacement,
