A bulk material conveyor belt system comprises a belt, a skirt, and a wear liner. In one embodiment, the MMC machining tool of the present invention is comprised of a support disk. Each module is electrically connected to another module by means of two inter-module connection elements and is essentially identical or homothetic to the other modules. An insertion hole, a fixing wire and a protruding portion are provided on the left side bolster and the right side bolster, and on the striker and the supporting bracket to determine positions of the left side bolster and the right side bolster and positions of the striker and the supporting bracket. According to the present invention, said group of heat exchangers comprises a set of finned or embossed plates, which are stacked and joined with each other so as to be adapted to create a number of passages for the counter-current flow andor cross flow andor mixed flow of said gases, wherein said group of heat exchangers is provided as a unitary piece. For this purpose, when density data quantized to several ranks are converted finally to binary data by using predetermined dot arrangement patterns, a dot arrangement pattern different from those for other color inks is prepared for a particular color ink.