Hi John, I don't have a B7100 to test this on, but after testing it out on my C405, I'm receiving the same results as you. From what you've said, you're doing all the steps correctly. Choose your desired paper tray, (it can't be on auto select), from the Original Size option, choose Custom Size, enter your X & Y parameters, (if you required any scaling I'd say select Auto% from Reduction/Enlargement & allow that feature to scale it to your desired paper), then start.
I've always used this from the glass vs ADH, & like you already discovered, that works fine from the glass but not from the ADH.
I'd reach out to support & open a ticket to determine if it's working as intended. I included a link here to the User Guide, found at Xerox.com and included a cheatsheet for "Original Size".
Also, with regard to this issue, in the System Admin Guide, there is this section with an instruction for resolving the original size detection error, but this option is actually NOT shown as this instruction states:
Resolving the Original Size Detection Error
For Copy, Fax, and Scan functions, the Resolve Original Size Detection Error setting allows you to set the
default size for an original document. This setting provides the following options.
• Prompt to Enter Size: This option displays a prompt at the printer control panel to enter the size of
the original document for the current job.
• Use Default Scan Size: This option uses the default original document size for the current job.
Note: You specify the default original size in this same configuration window.
To configure a response to Resolve Original Size Detection Error:
1. In the Embedded Web Server, log in as administrator, then click System > Defaults and Policies.
2. In the Common area, click Resolve Original Size Detection Error.
3. Click Copy, Fax, or Scan, then select an option.
4. In the Default Scan Size area, select an option.
5. Click OK.
This is actually a Versalink B7100 with software 59.14.01 (Launch +) but "Versalink B7100" is not listed as a "valid product name," in the 'Product Name' field, above.
The issue is this: a custom original size of 7.0 x 8.5 is programmed into the "Original Size/Custom Size" for copying and/or scanning into the B7100. For copying, a letter-sized tray is selected. The stack of 7.0 x 8.5 originals is loaded into the document feeder, and after the first original is scanned, the job stops and the prompt on the screen states:
"Unable to detect the original size accurately.
1. Press cancel to cancel this job and reload all of the originals.
2. Do not place anything but your originals into the Document Feeder Input Tray."
It seems the document feeder simply ignores the "custom size" programmed in. Does "custom size" only work from the glass?
This machine replaces an older WorkCentre model which was able to run this job.