Bad copies I put in new toner, faxes are ineligible to read, they have missing lines coming all the way down the paper.

Step 1 Check the top of your Canon fax/copy machine to see if your specific model has a protruding extension piece from the plastic delivery tray. Push the extension piece down if one is present on your model.
Step 2
Grip the bottom edge of the paper delivery tray at the front of the machine. Lift the tray upward to reveal the rectangular, plastic toner cartridge inside the machine.
Related Reading: How to Add Toner to a Canon X25
Step 3
Grab the handle at the top of the current toner cartridge and lift the cartridge upward. Pull the toner out of the machine and set it aside.
Step 4
Set your replacement toner cartridge over the empty space in the fax/copy machine. Ensure that the arrow near the bottom of the cartridge is facing down, and line up the protruding guide piece on the left side of the cartridge with the groove inside the machine. Push the toner downward until it snaps into position.
Step 5
Push the paper delivery tray back down, and lift up the extension piece if your model uses one.

When you see light print it can be from a few things. This is basically a laser printer with a fax machine so the same problems exist in both. The most common cause by far is simply low toner. If you take out the toner cartidge and gentl shake it side to side then put it back in. Now try printing again. This should be much darker. This may only last a few dozen pages (but can go a quite a bit more if you are lucky) but it shows you that you need to get a new toner cartridge. The other causes can be a image setting in the fax. In the control panel it will show you a setting for how dark it will print. Normally it is in the middle of the range. The last common thing is a fusor wire. This normally shows up as a error first but it can slowly fail. The fusor is the heater that bonds the toner to the paper. If it doesn't get hot enough then not all the toner sticks and you get light printing.

Normally the problem is low toner.

Are the fax from the different fax numbers or the same if the same may be there fax machine have them clean there scanner, if from varioue fax numbers then check your toner/drum unit and print out some internal reports such toner/drom order repkacement orders or one touch numers or meter read forms or make a copy if able to copy with this machine is line gone? Also check your fuser unit the hot part. also check your scan glass

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

I assume you talking about a panasonic DP-190? Do not clean the drum you may gently wipe it down, realize the drum puts the image on the paper, nick it, grease from hands, ,etc will effect copy qualilty. Remove the toner cart. clean any toner spilled. Drum may need replacement, print a toner/drum resupply form to see if the machine prints them cleanly

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

There should be a blue slider on top of the cartridge, but it probably is a bad drum cleaning blade inside of the cartridge.

yes change a toner and clean the glass area under nearth the toner.

You probably need new ink / drum / toner.

does it do it on copies and internal test as well???
1- check the thin strip of glass inside the machine and make sure it is clean, look at the toner are there any line on there that corresponds?? yes then replace.it could be coming from the drum or toner. I beleive the drum is a seperate piece from the toner

The CIS scanner has one of the LCD bits bad. If it is new, claim a warranty repair. Otherwise, strip the scanner out and go over all the solder joints

It's time to change NEW DRUM UNIT..and that's why your Toner will Not Last Longer because unnecessary toner (the black lines) will be on the copy every time the fax comes or you make a copy.