HP Color LaserJet CM4730 Multifunction Printer series - Manual (Page 107)

Custom paper sizes
This product supports a variety of custom paper sizes. Supported custom sizes are sizes that are within
the minimum- and maximum-size guidelines for the product but are not listed in the supported paper
sizes table. When using a supported custom size, specify the custom size in the print driver, and load
the paper in a tray that supports custom sizes.
ENWW Custom paper sizes 91