Abstract: An optical sensor of the present disclosure detects light from a sheet on which is printed at least one type of single-color ink among n types of single-color inks, the optical sensor including: a light source; a light receiver including first to (n?1)th light-receiving elements; a memory configured to store a correction value based on reference data obtained by receiving lights emitted from the first to n-th single-color inks individually in the light receiver by type of single-color inks; and a controller configured to correct detection data with the correction value, the detection data obtained by receiving, in the light receiver, light emitted from a sheet irradiated with light from the light source.

Abstract: An optical sensor of the present disclosure detects light reflected by a transported sheet and/or light transmitted through the sheet as well as light emitted from the sheet. The optical sensor includes: a light source configured to irradiate a sheet with excitation light and detection light; a controller configured to keep the light source turned off during each of light-off periods after the emission of the excitation light; and a light receiver configured to receive light resulting from reflection of the detection light by a sheet and/or light resulting from transmission of the detection light through the sheet in each of the light-on periods and receive phosphorescence emitted from the sheet in each of the light-off periods. The controller is configured to generate data of one pixel by summing up output values based on respective phosphorescence components received by the light receiver in each of the light-off periods.

Abstract: A paper sheet recognition apparatus (1) that recognizes a paper sheet based on an optical spectrum acquired from the paper sheet includes, a light source unit (31) including light sources arranged corresponding to partial areas on the paper sheet, a reading unit (32) having a light receiving surface to receive reflected lights from the partial areas, a sensor unit (34) that acquires an optical spectrum of light received by the light receiving surface, a memory (80) that stores an optical spectrum measurement condition, and a light-source control unit (72) that controls the light source unit (31) based on the optical spectrum measurement condition. The optical spectrum measurement condition includes information for identifying at least one light source corresponding to the predetermined partial area, information for identifying a timing for turning on the identified light source, and information for identifying a timing for turning off the light source.

Abstract: In order to efficiently acquire an optical characteristic from partial areas on the paper sheet, a paper sheet recognition apparatus (1) that recognizes a paper sheet by using an optical spectrum acquired from the paper sheet on a transport path (60) includes, a light source unit (31) including light sources arranged corresponding to the partial areas on the paper sheet, a reading unit (32) having a light receiving surface to receive reflected lights from the partial areas, a sensor unit (34) that acquires an optical spectrum from light received by the light receiving surface, a memory (80) that stores an optical spectrum measurement condition for acquiring an optical spectrum from a predetermined partial area on the paper sheet.