Image forming device using multiple factors to adjust print position

An image forming device, comprising:

• a carriage for mounting thereon a recording head, said carriage being scanned in a direction perpendicular to a travelling direction of a recording medium;
• a scale means for defining recordable dot positions along a scanning direction of said carriage;
• a sensor operable with said scale means for detecting each dot position of said scale means;
• a counter means for counting dots starting from a reference position based on an output of said sensor moved in said scanning direction;
• a recording medium detection means including a light emitting element for emitting light to said recording medium, a light detector for outputting a signal corresponding to an amount of reflected light of said light emitted from said light emitting element, a binary conversion circuit for converting an output of said light detector into a binary signal, and means for reading out a count value of said counter means to detect a side edge of the recording medium based on a change in an output of said binary conversion circuit when said carriage is scanned in the direction perpendicular to the travelling direction of the recording medium;
• an event state detection means for detecting a state of an event which is a factor fluctuating the output of said recording medium detection means;
• a correction value storage means for storing correction values to correct the read-out count value of said recording medium detection means based on different states of the event detected by said event state detection means;
• and
• a correction means for, when recording with the recording head, obtaining one of the correction values corresponding to a state of the event detected by said event detection means, from said correction value storage means, and for correction, with the correction value, said read-out count value as a position of the side edge of the recording medium obtained by said recording detection means.