Patent ID: 7689151
Filing Date: 2010-03-30
Classification: G03G

Abstract:
1. A multi-color image-forming apparatus comprising: an optical sensor having a light-casting section that casts light that is polarized in a predetermined direction and a light-receiving section that receives light that is polarized in a direction different from the predetermined direction; at least one high reflectance pattern configured for detecting toner position and including a high reflectance toner having high reflectance to a particular wavelength of the light cast by the light-casting section; and at least one low reflectance pattern including a high reflectance toner foundation and a low reflectance toner portion formed on top of the high reflectance toner foundation within a central portion of the high reflectance toner foundation, wherein the low reflectance toner having low reflectance to the particular wavelength of the light cast by the light-casting section, wherein the apparatus is configured to detect at least one of the high reflectance pattern and the low reflectance pattern by the optical sensor to correct a color shift; wherein the particular wavelength of the light cast by the light-casting section is from substantially 620 nm to substantially 720 nm, said high reflectance toner is at least one of a magenta (M) toner and a yellow (Y) toner, and said low reflectance toner is at least one of a cyan (C) toner and a black (K) toner; and wherein when the magenta (M) toner forms the high reflectance toner foundation, the cyan (C) toner forms the low reflectance toner portion and when the yellow (Y) toner forms the high reflectance toner foundation, the black (K) toner forms the low reflectance toner portion.