Patent ID: 7227563
Filing Date: 2007-06-05
Classification: B41J

Abstract:
1. An image writing apparatus for superimposing plural images onto a recording medium, comprising: plural scanning optical systems for forming individual ones of the plural images by scanning an image carrier with a beam, wherein each scanning optical system includes a lens having optical characteristics identical to those of corresponding lenses in all others of said plural scanning optical systems; wherein said lens is formed by use of a plurality of mold cavities which are divided into plural groups of cavities, including a first group of cavities and a second group of cavities; wherein lenses formed from the first group of cavities have relative differences in an optical parameter of the optical characteristics which are within an allowable range, whereas lenses formed from the second group of cavities have relative differences in the optical parameter of the optical characteristics which are not within the allowable range; and wherein each said lens of all of said plural scanning optical systems is formed from said first group of cavities.