I have finaly gotten the Canon Pixma MP495 working under Ubuntu 10.10, with full resolution capabilities of the printer.
This printer is only advirtised as having a max resolution of 4800×1200 DPI. However, I called Canon to get the full range of print resolutions and was informed that this printer is capable of 9600×2400 DPI.

I haven’t tested this below Ubuntu 10.04 but it should work fine.

For setting your MP495 printer up on your network without the use of a Windows or Mac machine (Fresh out of the box with Ubuntu) you will need to match your Routers SSID to the printers default SSID, and remove any security you have enabled. This will allow the printer to connect to your network.
Printer Defaults:
SSID: BJNPSETUP
IP ADDRESS: Automatic

Once you have done that you will need to activate the wireless lan on the printer.
Press the Maintenance button on the printer 15 times until you see what looks like a capital E without the top line. Then press the color start button. (refer to page 10 of your Network Setup Troubleshooting manual for an actual picture of the symbol) You should see the wifi light on the front of the printer turn on and be solid not be blinking. (If it is blinking check your routers SSID settings and match the Default SSID of the printer as listed above.

Now download AngryipScanner and install it by double clicking it. It should open in the Software center or with the Gdebi installer. (this may take a few minutes to install.)
Once you have installed AngryIPScanner, run it and change the ip range to include from 1 – 254 in the last octet. Then click start.
When it finishes look for an active connection with a Hostname like A001BF000000.local. Yours may be different but should be very simular.
The IP address given for that hostname is the IP address of your printer. Open Firefox and type that address in the address bar and press enter. From there you can configure you printer for the SSID, and encryption that you had on your router before the change, and set a static IP for the printer so you can manage it easily.
After you change the SSID and encryption on the printer you will have to go back to your router and change the SSID and encryption back to what it was before so your printer can connect again.

Now your network should be back the way it was and your printer should be connected

Now that you have successfully connected the printer to your wireless network continue with the rest of the installation.

Download the drivers for the mp495

You will be downloading cnijfilter-mp495series-3.40-1-deb.tar.gz.

Try this method first!
Extract cnijfilter-mp495series-3.40-1-deb.tar.gz to your Home directory.
Change the permissions of the install.sh file to run as an executable by Right clicking on install.sh and then left clicking Properties.
Click on the Permissions tab and put a check mark in the Allow Executing file as program box.
Then open a terminal and type:
sudo ./install.sh
Follow the prompts and if you are using the printer over the network select network when prompted. I you are using it via USB choose USB.
Don’t forget to scroll down to complete setting up your printer to use full resolution and set up the scanner.

If the first method didnt work try this.

Open a terminal and enter cd /home/*/cnijfilter-mp495series-3.40-1-deb/packages . (Enter your username where the astride is.)

For 64 bit systems you need to replace cnijfilter-common_3.40-1_i386.deb, and cnijfilter-mp495series_3.40-1_i386.deb with cnijfilter-common_3.40-1_amd64.deb, and
cnijfilter-mp495series_3.40-1_amd64.deb. For the printer setup.
For the scanner replace scangearmp-common_1.60-1_i386.deb, and scangearmp-mp495series_1.60-1_i386.deb with scangearmp-common_1.60-1_amd64.deb, scangearmp-mp495series_1.60-1_amd64.deb. Everything else is the same.

Now enter sudo dpkg -i cnijfilter-common_3.40-1_i386.deb and press enter.

Now enter sudo dpkg -i cnijfilter-mp495series_3.40-1_i386.deb and press enter.

After that is complete go to System-Administration-Printing and click on Add.

If you have set up your printer on your network you should find it listed under Network Printing after a moment. (It takes a second for Ubuntu to find it on the network.)
Select the Canon-MP495-series_XX-XX-XX-XX-XX then click [Forward].
It will tell you that it is searching for Drivers. (wait for it…..)
In just a second a new window will appear asking for the Description of the Printer. Give it a name in the Location Field.

Now that you have a functioning MP495 printer, printing at a meager 600 DPI, lets make it better!

Change the Available Resolutions for Printing

Open another terminal and edit the first of two postscript files for this printer. gksudo gedit /etc/cups/ppd/Canon-MP495.ppd

Find:

*OpenUI *Resolution/Output Resolution: PickOne

Then we are going to replace the text from:

*OpenUI *Resolution/Output Resolution: PickOne

to:

*CloseUI: *Resolution

With:

*OpenUI *Resolution/Output Resolution: PickOne
*DefaultResolution: 4800dpi
*Resolution 600dpi/600 DPI: “<</HWResolution[600 600]>>setpagedevice”
*Resolution 1200dpi/1200 DPI: “<</HWResolution[1200 1200]>>setpagedevice”
*Resolution 2400dpi/2400 DPI: “<</HWResolution[2400 2400]>>setpagedevice”
*Resolution 2400dpi/4800 DPI: “<</HWResolution[2400 4800]>>setpagedevice”
*Resolution 2400dpi/9600 DPI: “<</HWResolution[2400 9600]>>setpagedevice”
*CloseUI: *Resolution

Save and close gedit.

Open another terminal and edit the second postscript file for this printer. gksudo gedit /usr/share/ppd/canonmp495.ppd
Find:

*OpenUI *Resolution/Output Resolution: PickOne

Then we are going to replace the text from:

*OpenUI *Resolution/Output Resolution: PickOne

to:

*CloseUI: *Resolution

With:

*OpenUI *Resolution/Output Resolution: PickOne
*DefaultResolution: 4800dpi
*Resolution 600dpi/600 DPI: “<</HWResolution[600 600]>>setpagedevice”
*Resolution 1200dpi/1200 DPI: “<</HWResolution[1200 1200]>>setpagedevice”
*Resolution 2400dpi/2400 DPI: “<</HWResolution[2400 2400]>>setpagedevice”
*Resolution 2400dpi/4800 DPI: “<</HWResolution[2400 4800]>>setpagedevice”
*Resolution 2400dpi/9600 DPI: “<</HWResolution[2400 9600]>>setpagedevice”
*CloseUI: *Resolution

Save and close gedit.

Now restart the cups service.
with sudo service cups restart in Ubuntu 10.10 and I think 10.04 too.
or sudo /etc/init.d/cups restart in previous verions.

You can now print with resolutions ranging from 600 DPI to 9600 DPI!
Enjoy.

For getting the scanner working download the drivers from here
extract scangearmp-mp495series-1.60-1-deb.tar.gz into your home directory.
Open terminal and type. (Replace the astride with your user name.)
cd /home/*/scangearmp-mp495series-1.60-1-deb
sudo ./install.sh
Then to use your scanner, open terminal and type.
scangearmp
A Big thanks goes to BartmanMN for finding the Scanner drivers.
Enjoy!