JJ wrote on 2016/01/14:

Roger Mills wrote:

Any lack of "blackness" is likely to be an issue with the printer
itself, and nothing to do with the cable.

Expired toner? Is that possible?

http://computer.howstuffworks.com/laser-printer.htm

How old is the laser printer? Have you ever cleaned the corona wire?
Use an ear swab wetted with isopropyl alcohol to *gently* glide across
the corona wire on all sides (that you can reach). The printer's manual
should tell you about corona wire maintenance.

http://www.inktechnologies.com/blog/...-corona-wires/

The "tool" in a slider built into the drum housing, if it has one. Back
a long time ago when I had a laser printer, they didn't have this. I
could see the corona wire (probably had to remove the toner cartridge)
and had to clean it by hand. If you use a swab, don't have it so wet
that it drips alcohol into the drum housing; else, you'll have to let it
dry out for a long time (only applies if the wire is enclosed). You can
see how some folks show cleaning the wire at:

https://www.youtube.com/results?sear...or ona%20wire

The inbuilt wire cleaning "tool" might not be all that effective. It
scraps the wire but only on a couple sides, and it may skip over some
crud that is sternly coated on the wire. If you routinely clean the
corona wire (every cartridge change and after some number of pages, like
500 prints) then it may not get so overly coated that the inbuilt
cleaning tool would be sufficient.

You did not mention brand and model so just generic help can be given to
you. If you add the brand and model to the search then you might find
articles or videos specific to your printer.

Another trick I learned long ago when toner looked like it was getting
low (faint printing) was to remove the toner cartridge and tip it left
and right. Do not shake, just tilt left and right. That will
redistribute any toner that is mostly deposited to one side of the
cartridge. Printing is often lopsided, especially for text, where the
left side of the page has more dense printing than the right side.

The static electricity process of creating an image on the drum to
transfer to the paper (and then heat the dusting of ink laying on the
paper to melt its binder so the ink does stick to the paper) won't work
if the drum isn't clean. The fusing is separate from the drum. If the
corona wire is coated with filth then the result is the ink doesn't
transfer to the paper (static charge is weak). So, again, make sure the
corona wire is cleaned every time you replace the toner or when there is
faint printing.

Doesn't the printer manual provide some troubleshooting and cleaning
instructions? You might also need to clean the drum. If the ink is not
getting completely getting lifted off to the statically charged paper,
well, the ink is left back on the drum. Just like with the wire, use
isopropyl alcohol to clean the drum with a lintfree cloth (paper towel
would probably be too abrasive and the soft paper towels leave lint).
Eyeglass lens cleaning *cloths* are probably okay (not those alcohol
soaked paper wipes in a tear open packet). Don't expect to reuse the
cleaning cloth as it will be soiled with ink that you cleaned off the
drum.

You can get 99% isopropyl alcohol at a pharmacy (most grocery stores
only have the 70% stuff). Do NOT use rubbing alcohol, wood alcohol, or
methanol. Those leave behind a residue.