Encoder in facsimile apparatus generates code words with one bit address indicating remaining bits are raw unencoded data when number of pixels in a run length are below a predetermined number

A pixel data encoder for use in a facsimile apparatus, the encoder comprising:

• (a) a first in first out memory for storing sequentially received one-dimensional binary pixel data sequences in synchronism with a data acquisition clock;
• (b) a run length determiner coupled to the first in first out memory to receive the one-dimensional binary pixel data sequences stored in the first in first out memory, the run length determiner determining a run length of each of the binary pixel data sequences by calculating the number of pixels contained in each of the binary pixel data sequences received from the first in first out memory;
• and
• (c) an encoding section for receiving from the run length determiner the run length of each of the binary pixel data sequences and issuing one of a first and second type of code word for each of the binary pixel data sequences;
• wherein
• (1) the first type of code word includes a one-bit address signal for indicating that raw unencoded data will be issued and N-bit raw unencoded data, the encoding section issuing the first type of code word when the run length of the binary pixel data sequence for which the encoding section is issuing one of the first and second types of code word is equal to or less than a predetermined run length N, N being an integer greater than 1;
• (2) the second type of code word includes an address code and a remainder code, the address code consisting of a series of consecutive binary level "1"s and a binary level "0", the series of consecutive binary level "1"s having a bit length equal to M-2, and the remainder code consisting of a binary sequence representing the run length of the binary pixel data sequence for which the encoding section is issuing one of the first and second types of code word, the remainder code is formed by deleting the most significant bit of the binary pixel data sequence, M representing a total number of binary digits of the run length of the binary pixel data sequence for which the encoding section is issuing one of the first and second types of code word, the encoding section issuing said second type of code word when the run length of the binary pixel data sequence for which the encoding section is issuing one of the first and second types of code word exceeds N.