1. A character recognition method executed by a computer, the character recognition method comprising: specifying a character recognition target item from image data of the form; calculating a position and size of an image character in the specified character recognition target item; calculating a score that quantifies a possibility of handwriting or printing by analyzing the image character on the basis of characteristics of handwritten and printed characters; discriminating on the basis of the score whether the image character is handwritten or printed; calculating an average value of scores of characters of the recognition target item, and checking whether or not the recognition target item includes both handwritten and printed characters; and performing character recognition on each character of the recognition target item with an appropriate character recognition engine for a result of discriminating whether said each character is handwritten or printed and a result of checking whether the recognition target item includes both handwritten and printed characters, wherein: the calculating of the score includes: calculating a first score that quantifies a possibility of handwriting or printing by analyzing a gradation distribution of the image character; calculating a second score that quantifies a possibility of handwriting or printing by analyzing a character color of the image character; calculating a third score that quantifies a possibility of handwriting or printing by analyzing a gradation ratio between a turning point where a character stroke extracted from the image character changes and the character stroke other than the turning point; calculating a fourth score that quantifies a possibility of handwriting or printing by analyzing contrast at an edge of the character stroke, the contrast indicating a degree of change in gray level at a boundary between the character stroke and background; calculating a fifth score that quantifies a possibility of handwriting or printing by analyzing vertical sizes and center positions of the characters on the basis of a position and size of the image character; and calculating a sixth score that quantifies a possibility of handwriting or printing by analyzing character sizes and pitch on the basis of the position and size of the image character; and in discriminating whether the image character is handwritten or printed, the first to sixth scores are aggregated by weighting the first to sixth scores according to respective importance.