An image recording apparatus has a platen supporting the under side of a sheet conveyed in a conveying direction. The platen has upstream ribs and a downstream rib, between which a marginless recording region lies. The platen also has first ribs, second ribs and third ribs, respectively supportable of front and rear end portions of the sheet, formed in the marginless recording region, and spaced at suitable intervals perpendicular to the conveying direction. Grooves are formed between the first to third ribs and extend in the conveying direction. An ink absorber is further provided on a bottom plate of the platen positioned under the downstream rib and communicates with groove absorbing a surplus portion of the discharged ink. The platen is simple in structure and performs marginless image recording without staining either side of the sheet with easy size control of the ink absorber.