Method for correcting passbook printer and passbook printer

摘要

PROBLEM TO BE SOLVED: To provide a bankbook printer and a correction method of the bankbook printer capable of automatically correcting a reference for image sensor even when being subjected to an influence of external light in an installation circumstances or when the image sensor gets deteriorated.SOLUTION: The bankbook printer includes: an image sensor for reading a bankbook; an event detection section that detects an event to perform a black reference correction on the image sensor; a shutter control section that, when the event detection section detects the event, closes a shutter of a bankbook insertion port; an illumination control section that turns off an illumination in the printer; a black reference correction value calculation section that calculates a black reference correction value; and an update section that updates a present black reference correction value to a black reference correction value calculated by the black reference correction value calculation section.SELECTED DRAWING: Figure 4