Recording apparatus with modular LED array of higher production yield

Claim 1

In a recording apparatus for linewise recording information on a photoreceptor moving along a fixed path, said apparatus comprising a recording head carrying a multiplicity of addressable and energisable pointlike radiation emitters arranged in at least one row having its length extending transversely of the path of the photoreceptor, said row being composed by the assembly in generally a line of a plurality of chip means each carrying a plurality of radiation emitters disposed in uniformly spaced apart relation in at least one row, and electrical control means for said radiation emitters, the improvement wherein said recording head comprises an elongated metal bar onto which a plurality of modules are fitted in good heat-conductive relationship, each such module comprises an electrically conductive base plate onto which a plurality of said emitter chip means is mounted generally in said line in generally abutting relation in good electrical and heat-conductive relationship, with the emitters thereof aligned in at least one extended row, the length (o) of each base plate parallel to the axis of the emitter row thereon being smaller than the aggregate length (n) of the chip means thereon so that on both ends of the base plate an end of a terminal chip means in said line extends beyond the boundary of the base plate, the spacing of the end edges of each chip means from the outermost radiation emitter thereon and the spacing of adjacent modules carrying said chip means being sufficiently close that at least one uninterrupted overall row of equally spaced radiation emitters is formed from the emitters of said modules along the length of the recording head, and said electrical control means is in the form of at least one elongated control chip mounted on each such module in common to each such extended row of emitters thereon, said control chip running parallel with its associated extended row of radiation emitters and being provided with a plurality of output terminals that are each connected by wire bonding to a corresponding radiation emitter, said control chip comprising integrated shift register means, latch register means and drivers, and also an input terminal for the serial-in loading of the shift register means and an output terminal for connection of the shift register means to the input terminal of the shift register means of the control chip of the next module.