A copier for electrostatically forming on a photoconductive element a latent image representative of a document which is laid on a glass platen by illuminating the document through a slit, developing the latent image, and then transferring the developed image to a paper sheet. Optics of the copier is movable between the operating and non-operating sides which are respectively defined at the front and rear sides of the copier body, thereby illuminating the document. A paper sheet is fed from a lower part of the copier body, while a copy produced by reproducing the document on the paper sheet is discharged from a position above the glass platen. A reference position on the glass platen where the document is to be laid is defined at the non-operating side when an automatic document feeder is used and at the operating side when it is not used.
