HP PCL/PJL reference (PCL 5 Color) - Technical Reference Manual

EN The PCL Print Model 5-41
When using the 300 dpi User-Defined Pattern header (see Table 5-5),
set the eight bytes of header information to the following values:
Byte 0 – Format 0 (00 hex)
Byte 1 – Continuation 0 (00 hex)
Byte 2 – Pixel Encoding 1 (01 hex)
Byte 3 – Reserved 0 (00 hex)
Byte 4/5 – Height in Pixels 0 / 16 (00 / 10 hex)
Byte 6/7 – Width in Pixels 0 / 32 (00 / 20 hex)
Byte 8 – Begins the first bytes of binary data.
The PCL code below downloads the user-defined pattern and assigns
it an ID number of 3.
1. Specify the pattern ID number:
2. Send the User-defined Pattern command:
?*c3G Assigns an ID number of 3 to the pattern
data which follows.
?*c72W Specifies that 72 bytes are to follow (8
bytes for the header plus 64 bytes of
pattern data).