Methods and apparatus for detecting toner fade in an imaging device

A method of detecting toner fade in an electrophotographic imaging device, the method comprising, looking for relative variations in intensity of light reflected from a toner area, wherein:

• the electromagnetic energy is substantially light of a primary color;
• the toner area comprises a first toner layer having a first color and a second toner layer having a second color;
• and,
• the first color is substantially a complement of the primary color.

A method of detecting toner fade in an electrophotographic imaging device, the method comprising:

• providing a support surface;
• supporting a first toner area on the support surface;
• supporting a second toner area on the support surface;
• producing light with an energy source;
• directing the light at the support surface;
• moving the first and second toner areas past the light in succession;
• detecting intensity of light reflected from the first toner area;
• detecting intensity of light reflected from the second toner area;
• and,
• comparing intensity of light reflected from the first toner area to intensity of light reflected from the second toner area to determine whether a difference in the intensities is present which is indicative of a low toner condition.

An apparatus for detecting toner fade in an electrophotographic imaging device, the apparatus comprising:

• a support surface configured to movably support thereon a toner area, wherein the surface is configured to be substantially light-reflective with respect to ultraviolet light;
• at least one energy source configured to produce ultraviolet light, wherein the at least one energy source is further configured to direct at least a portion of the ultraviolet light toward the toner area;
• at least one energy detector configured to detect relative intensity of ultraviolet light reflected from the toner area;
• and,
• a controller in communication with the at least one energy detector and configured to determine whether a low toner condition exists based on variations in the ultraviolet light reflected from the toner area.

A method of detecting toner fade of a given toner in an electrophotographic imaging device, the method comprising:

• providing a support surface on which a toner area is movably supportable;
• depositing a toner area comprising toner of a given subtractive primary color on the support surface;
• directing light onto the toner area;
• moving the toner area relative to the light;
• and,
• detecting relative intensity of light which has substantially a predetermined wavelength, and which is reflected from the toner area, wherein the predetermined wavelength corresponds to a primary color of which the given subtractive primary color is a complement.

A method of detecting toner fade of a given toner in an electrophotographic imaging device, the method comprising:

• providing an energy source configured to produce light having a predetermined wavelength;
• providing a support surface on which a toner area is movably supportable, and which is substantially reflective with respect to the light produced by the energy source;
• depositing a toner area on the support surface, wherein the toner has a given color;
• producing light having the predetermined wavelength, wherein the given color is substantially non-reflective with respect to the light;
• directing at least a portion of the light toward the toner area;
• and,
• looking for light reflected from the toner area, wherein the light is substantially ultraviolet light.

A method of detecting toner fade of a given toner in an electrophotographic imaging device, the method comprising:

• providing an energy source configured to produce light having a predetermined wavelength;
• providing a support surface on which a toner area is movably supportable, and which is substantially reflective with respect to the light produced by the energy source, wherein the support surface is substantially white;
• depositing a toner area on the support surface, wherein the toner has a given color;
• producing light having the predetermined wavelength, wherein the given color is substantially non-reflective with respect to the light;
• directing at least a portion of the light toward the toner area;
• and,
• looking for light reflected from the toner area.

An apparatus for detecting toner fade in an electrophotographic imaging device, the apparatus comprising:

• a support surface configured to movably support at least one toner area, wherein the support surface is configured to substantially reflect electromagnetic energy;
• at least one energy source configured to produce electromagnetic energy, and to direct at least a portion of the electromagnetic energy toward the at least one toner area;
• and,
• at least two energy detectors, each detector configured to detect relative intensity of electromagnetic energy that falls within an associated range of wavelengths, wherein the energy detectors are further configured to detect intensity of electromagnetic energy reflected by the at least one toner area.

An apparatus for detecting toner fade in an electrophotographic imaging device, the apparatus comprising:

• a support surface configured to movably support at least one toner area, wherein the support surface is configured to substantially reflect electromagnetic energy;
• at least one light source configured to produce light of a predetermined wavelength, and to direct at least a portion of the light toward the at least one toner area;
• at least one light detector, each detector configured to detect relative intensity of light that falls within an associated range of wavelengths, wherein each light detector is further configured to detect intensity of light reflected by the at least one toner area;
• and,
• a plurality of optical gates configured to selectively control the passage light therethrough.