Canon PIXMA MX850 Series Quick Start Manual page 12

(20) OK button
Finalizes your selection for the menu or setting item.
This button is also used to dismiss the error message and resume the machine's normal
operation after resolving a printing error or removing jammed paper, or to eject
documents remaining in the ADF.
(21) Back button
Cancels operations and returns the LCD to the previous screen.
(22) Feed Switch
Selects the paper source. Press to switch the paper source between the Rear Tray and
the Cassette.
To print out received faxes, the paper source selected on the FAX settings screen is
used.
(23) FAX Quality button
Sets the scan contrast and resolution of the fax you are sending.
(24) Search button
Searches for photos on the memory card with the specified shooting date.
(25) Enlarge/Reduce button
Specifies the enlargement or reduction ratio for copying.
(26) Two-Sided button
Specifies the settings for duplex copying.
(27) Rear Tray lamp (top) / Cassette lamp (bottom)
These lamps indicate the currently selected paper source.
(28) One-Touch Speed Dial buttons
Press these buttons to display pre-registered fax/telephone numbers or groups.
8 Before Using the Machine