Homelite HL-1050, HL-P2500, HL-1660E, HL-2400CE, HL-1450, HL-1250, HL-1470N, HL-1070 Number of repeats

10/10/03

<Compressed Image Data>

Data compression compresses the original image data word by word (16 bits).

The compressed data consists of both horizontal compression which uses 16 bit, 8 bit and 4 bit repeating patterns within 1 word or 2 words of data and vertical compression which indicates how many times to repeat the same data as in the previous line within 1 word of data.

Non-compressed data

When the most significant bit in the first 2 bytes is 0, the printer goes into non-compression mode. The following 11 bits then indicate the number of words of data, the least significant 4 bits are not used. After that, the image data follows word by word.

15	14	4	3	0
0	data word count (11 bits)			not used

data 1 (16 bits)

:

data n (16 bits)

16 bit repeating compressed data

When the most significant 3 bits in the first 2 bytes are in the order 1, 0, 0, the remaining 13 bits indicate the number of times to repeat 16 bit data. The following 2 bytes should be the 16 bit data to repeat.

15	14	13	12	0
1	0	0		number of repeats(13 bits)
				data to repeat(16 bits)

8 bit repeating compressed data

When the most significant 3 bits in the first 2 bytes are in the order 1, 1, 0, the following 5 bits indicate the number of times to repeat 16 bit (two by 8 bits) data. The remaining 8 bits should be the 8 bit data to repeat.

15	14	13	12	8	7	0
1	1	0	number of repeats		data to repeat(8 bits)
	(5 bits)

4 bit repeating compression data

When the most significant 3 bits in the first 2 bytes are in the order 1, 0, 1, the following 4 bits are the 4 bit data to repeat. The remaining 9 bits indicate the number of times to repeat the 16 bit (4 by 4 bits) data.

15	14	13	12	9	8	0
1	0	1	data to repeat		number or repeats(9 bits)
	(4 bits)

Vertical repeating compressed data

When the most significant 3 bits in the first 2 bytes are in the order 1, 1, 1, the remaining 13 bits indicate the same data words as in the previous line.

15	14	13	12	0
1	1	1	the same data words as in the previous line (13 bits)

The printer cannot support the APT and HRC function in the 1200 dpi printing mode.

CHAPTER 2 "PCL" - 85