Electrophotographic Photoreceptor Having a Spectral Marker and Electrophotographic Printer Using the Same

An EP imaging system, comprising:

• a controller;
• a photoreceptor including a spectral marker having an absorbance wavelength maximum;
• an image writing light source for writing a latent image on the photoreceptor, the image writing light source having an emission wavelength maximum;
• a spectral marker detector light source having another emission wavelength maximum for illuminating the photoreceptor;
• and
• a spectral marker detector, in communication with the controller, providing a light reflectance signal representative of the reflectance of the spectral marker to the controller wherein the controller modifies operation of the printer based on the reflectance signal.