Can you post a screen capture of CS6's File > Print (Photoshop Print Settings) ? Use the insert image (small camera icon in Reply) to upload the screen capture.
Photoshop is seeing the vertical page layout from the driver and shows that in the UI, and passes that information to the driver -- so only the OS or driver could be messing up and changing the page layout.
Also, I haven't heard of this happening with any other printers.
Are you sure you're using the Brother driver and not a Guten/GimpPrint driver?
Thanks for reply.
As you say, horizontal page was printed without trouble.
For example, above screenshot was printed smoothly when it had been set horizontal A4 on print dialog. The vertical page layout, however, missed.
I re-installed Brother driver.
I have a Brother MFC6490CW On my Mac the Brother CUPS driver is installed.
I notice the vertical offset on my JIS B4 paper. To fix this I click on Page Setup. then I go to Page Size in Print Preferences. In the list I select "Manage Custom Sizes" and there I click + to add my custom size and name it "B4 Center" where my margins are .25 inches all around.
Then in Page Size I select B4 Center from the list and it will print centered on my Brother.
1. First click the button marked in red.
2. On "Paper Size" choose Manage Custom Sizes which should be at the bottom of the paper sizes list.
3. Click on "+" to add a custom size. Double-click on Untitled to rename it to A4 Center. Set Page size and margins. Press OK
4. From your Page Size menu, A4 Center should be at the bottom as a custom size, select it and use it in Photoshop.
Since there is already A4 in the paper size list, can you rename the custom size to A4 Center, select "A4 center" and see if it works?
Also maybe making the custom paper size smaller than A4 might work 20.0 x 29.0 cm as an example
If this does not work, you may have to save the file and use Preview to print it.