BAR CODE TYPE DUST REMOVAL MAT MANAGEMENT METHOD

PROBLEM TO BE SOLVED: To allow the fluctuation of a read condition in a bar code read work of a dust removal mat, and to surely and quickly perform the read work.SOLUTION: A clearance (a read depth h) of a light beam transmission part 26 of a hand-held type optical reader 2 and a surface of a dust removal mat 4 is adjusted to the range of 10 to 200 (mm), and a speed (a read speed v) of moving the hand-held type optical reader 2 in parallel is adjusted to the range of 0 to 100 (mm/second). Further, a read angle (degrees) formed by a light beam 28 radiated from the light beam transmission part 26 and a surface of an information sheet 6 when stopped at a position at which signals from the hand-held type optical reader 2 become maximum is defined as 0 degree, a read upper limit angle is adjusted to the range of 0 to +15 (degrees), and a read lower limit angle is adjusted to the range of -15 to 0 (degree). A bar code 8 on the information sheet 6 is read at a high speed by light beam scan by the hand-held type optical reader 2, and the dust removal mat 4 is managed by obtained mat information.