I am using a Canon Pixma MG5420. Here is my process for scanning multiple PDF pages into a single document on a MacBook Pro:
1. Place document on the scanner.
2. Open the Preview application. If needed, the Preview application can be located from the Search function (magnifying glass.
3. From the menu bar, select File --> Import from Scanner --> (name of your printer). This opens a second window titled Import from Canon MG5400 series, and the printer immediately produces an overview of your document.
4. Use gripper "handles" (blue dots) to set the desired scan area if needed.
5. Make your scan preferences in the dialogue section on the right side of the window. NOTE: Be sure that PDF is selected as the format and that the "Combine Into Single Document" checkbox immediate below is checked.
6. Click the Scan button at the lower right of the window and allow the printer to complete scanning the first page.
7. Remove the first document and place the next document on the scanner.
8. Click the Overview button at the bottom right of the window and allow printer to complete the overview of the second page.
9. Use the blue gripper handles to set the desired scan area if needed.
10. Click the Scan button at the bottom right of the window and allow printer to complete scanning the second page.
11. Repeat steps 7-10 as many times as necessary until all pages are scanned.
12. Return to the open Preview window which will now display the pages which have just been scanned.
13. From the menu bar, select File --> Move To. This opens a dialogue box which allows you to name your PDF file and select the location where you want it to be filed. Make these choices and save your multi-page PDF document.
