Question about Canon PIXMA MP780 All-In-One InkJet Printer

2 Answers

Dark copies. Hi. Is there a way to clean the "reading glass" (panel)? Its so foggy underneath and makes very dark copies(blocking the exposure lamp) Thanks.

Posted by on

  • Tech4all
    Tech4all Oct 23, 2008

    Hi Check. The optic is encased inside the scanner unit..

    I 'd be able to detach it from the printer but don't know how remove the housing to get to the glass .

    I have it for 2/3 years. I guess dust & heat (Humit) starts to build up.

  • Tech4all
    Tech4all Oct 23, 2008

    Its all plastic casing...No screws..Kind of taps locking. I'm afraid to break it and mess up the scanner...

    I used to work for Canon USA for 17 years (Field Svc Technician) . The first thing we deal with copy quality is to clean the optics BEFORE messing around adjustments. I have seen how fast the optic system gets dirty...(Some within 6months) depend on models,and regardless the environment around it.

    Sure , Pixma780 has fl/lamp that creates less heat but still accumulates in time.

    I'm retired now....and not as techy as used to be,and don't have alot of money to buy a new one.

    Thanks for your help.



2 Answers

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

I can copy on my pixma mp780 but it won't print anything.
Says does not locate the port? Bought a new USB cable and that didn't help.

Posted on Feb 25, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An user who is expert in 3 categories / brands.

  • Canon Master
  • 1,362 Answers

If it's underneath the glass, you need to remove the top and clean it. The oher issue here is Why is it getting foggY??? THAT should be a concern to you.
Either let it dry naturally, or remove the top to clean.

Posted on Oct 23, 2008

  • CheckitRight
    CheckitRight Oct 23, 2008

    That is not normal, it doesnt matter how long youve had it, it must be somewhere that retains high humidity.

    First remove the ADF, then remove the plastic casing for the top, there will probably be about 6-8 screws depends on the model, once its off ( I would leave the connections, and just leave the top hanging) and clean it, then re-install it.

  • CheckitRight
    CheckitRight Oct 23, 2008

    Hey there fellow canon tech, I've only seen that on the copiers not on other machines and canon is known for being dust sensitive.

    Anyway, good luck.



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya Technician can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Technician (only for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Konica 1212 copies to dark

1st the basic cause of dark/grey copies DUST. Clean w/ alcohol cloth then dry cloth totally all mirrors and the platen glass both side. If still dark check the "Optic slit " right in the upper of your halogen lamp remove it, still dark Check your halogen lamp maybe it already oxidized. The last solution adjust the CVR .

Nov 27, 2014 | Konica Minolta Konica 1015 1120 1212 Toner...

1 Answer

My copies are not very dark

Is the problem only with copies? Does the machine also print light?
If is it copy only, remove the glass and clean the lamp and mirrors in the scanner.
If it is both copy and print, then you should clean the laser shield glass and replace the developer.

Jul 28, 2010 | Sharp AR-M455N Copier

1 Answer

I have a FP7113 it only makes dark copies

dark copies you mean there is a dark background but image is still there?
it is usually happens when all mirrors and **** glass becomes dirty. you should clean it
well if you mean an image with pure black copy output, probably your exposure lamp is busted or the thermostat is open. :)

Mar 03, 2010 | Panasonic FP-D355DC Copier

1 Answer

Cannon 6 RE PC gives black copies

does the lamp under the platen glass turns on when copying? if not you might need a new exposure lamp...but if you get an image but its very dark, if you are mechanically inclined you can clean the mirrors and lens and the bottom of the platen glass because after many years of use dust will make the optics dirty and cause the copies to be very dark. hope this helps.

Dec 31, 2009 | Canon Office Equipment & Supplies

1 Answer

Copier is making copies super dark and with a white line in the botton of the page

Hello sir; Check the exposure lamp, is out or weak it make dark copy.

Aug 17, 2009 | Canon Office Equipment & Supplies

1 Answer


what is your exposure lamp brigthness condition? checkyour upper high voltage adjustment , check your exposure lamp & bright it & clean your copier lens.thanks.

Oct 05, 2008 | Minolta Office Equipment & Supplies

2 Answers

Adjustment program

Try cleaning the Auto Exposure sensor, or disabling the AE feature in standard settings. Some copiers have exposure calibration in standard settings too. Increasing the lamp intensity may cause further premature wear down the process line. (What machine have you got?)

Aug 27, 2007 | Gestetner - DSm660 Digital Imaging System...

1 Answer

Dark Copies

Jim, A couple of things: 1. OEM (Canon original) toner cartridge or remanufactured/compatible? The first place to start is always with the toner cartridge when image problems occur. Pull the cartridge out and draw back the drum cover. Check to see if the drum is a nice "clean" blue color or if the lines and spots are on it like you described. (These two areas should be handled by someone with experience in copy service) 2. The next thing would involved cleaning under the copy glass. Build up from dust, etc causes a "fogginess" that makes the machine try to adjust the intensity of the exposure lamp to conpensate for this. 3. Also could be a bad upper fuser roller if you started having any paper jams when to paper exits.

Jul 18, 2007 | Canon imageCLASS D320 Digital Copier

2 Answers

One side copy dark

I would check the scanner slit glass under the toner cartridge. Clean the optics, pull the PCU out and clean the LED erase lamps. After this I would say it was the PCU. I NEVER would mess with the exposure baffles or the focus.

Mar 31, 2007 | Ricoh Aficio 2015 Copier

Not finding what you are looking for?
Canon PIXMA MP780 All-In-One InkJet Printer Logo

Related Topics:

128 people viewed this question

Ask a Question

Usually answered in minutes!

Top Canon Office Equipment & Supplies Experts


Level 3 Expert

102366 Answers

old marine
old marine

Level 3 Expert

2036 Answers

Donald DCruz
Donald DCruz

Level 3 Expert

17130 Answers

Are you a Canon Office Equipment and Supply Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides