The invention relates to a sheet-fed scanner (300) comprising: an illumination device for emitting a luminous flux covering several spectral bands which is intended to illuminate a sheet (204) to be scanned, a focussing device (150), and a detection module (360) comprising a sensor (164) which comprises a plurality of rows (166, 168, 170) of sensitive elements, each sensitive element being provided to deliver an electrical energy that is proportional to the intensity of the luminous flux received, and each row being provided to have its sensitivity peak for one of said spectral bands, the focussing device being provided to focus, onto each of the rows, part of the luminous flux reflected by said sheet, the sheet-fed scanner (300) being characterised in that the detection module (360) comprises a non-prismatic spectral shift device (305) for shifting each part of the luminous flux thus focussed, parallel to said rows (166, 168, 170), the shift being different for each row (166, 168, 170).