HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part I

15-18 Raster Graphics EN
The range of numbers for the control byte is shown below.
Note Another method to calculate the number needed in the control byte
for some number of repetitions is to subtract the number of desired
repetitions from 256. For example, the control value for 3 repetitions
(4 occurrences) of a byte is 256 minus 3 = 253.
A zero or positive value in the control byte means that the subsequent
byte or bytes are non-replicated bytes of data. The value of the
control byte plus one indicates the number of data bytes that follow.
For example, a control byte of 0 means the following 1 byte is literal
raster data. A control byte of 6 indicates that the following 7 bytes are
literal raster data bytes.
Table 15-3 Literal Pattern Values
# of Bytes Binary value Decimal value
1 0000 0000 1
to to to
127 0111 1111 127
Table 15-4 No Operation Value
NOP value Binary value Decimal value
128 (-128) 1000 000 128
Table 15-5 Repeated Pattern Values
# of Repetitions Binary value
1
1. These negative values are represented by taking the twos complement of the value
of the number.
Decimal value
1 (-1) 1111 1111 255
to to to
127 (-127) 1000 0001 129