Methods and apparatus to detect an ink ribbon based on types of light
Provided herein are devices, systems, methods and various means, including those related to printer systems and, more particularly, relate to methods, apparatuses, systems and other means for monitoring a printer ribbon. Some embodiments use a multi-element detector, which is configured to detect a particular type of light emitted from a light emitter. The multi-state detector can include two sensors, one of which includes a polarizer filter that blocks polarized light. Embodiments can be used to determine, among other things, whether or not a printer ribbon is installed in a printer without the use of a snap plate.
1. An apparatus, comprising:
a light emitter positioned along a path traveled by an ink ribbon through a media processing device, the light emitter to emit un-polarized light into a field of view, wherein the light emitter is positioned relative to the path such that at least a portion of the un-polarized light becomes polarized via reflection off the ink ribbon; and
a multi-element detector configured to indicate:
whether light is present in the field of view; and
whether the unpolarized light emitted by the light emitter was polarized via reflection off the ink ribbon.
2. The apparatus of claim 1 , wherein the multi-element detector comprises:
a common photo detector configured to generate a common light signal indicating whether light was detected by the common photo detector; and
a polarized photo detector configured to generate a polarized light signal associated with whether the polarized light was detected by the polarized photo detector.
3. The apparatus of claim 2 , further comprising a processor configured to determine a type of the ink ribbon based on the common light signal and the polarized light signal.
4. The apparatus of claim 2 further comprising:
a processor configured to:
receive the common light signal;
receive the polarized light signal; and
determine whether an inked portion of the ink ribbon is in the field of view based on the polarized light signal and the common light signal.
5. The apparatus of claim 2 further comprising:
a processor configured to:
receive the common light signal;
receive the polarized light signal; and
determine whether a non-inked portion of the ink ribbon is in the field of view based on the polarized light signal and the common light signal.
6. The apparatus of claim 2 further comprising:
a processor configured to:
receive the common light signal;
receive the polarized light signal; and
determine whether there is an absence of the ink ribbon in the field of view based on the polarized light signal and the common light signal.
7. The apparatus of claim 2 , wherein:
the common photo detector and the polarized photo detector comprise the same type of light sensor; and
the polarized photo detector further comprises a polarizing filter.
8. The apparatus of claim 7 , wherein the polarizing filter is a dichroic analyzer film.
9. The apparatus of claim 1 , wherein the light emitter is configured to shine the light onto the ink ribbon such that the light's angle of incidence is within 5 degrees of Brewster's angle associated with material of the ink ribbon.
10. The apparatus of claim 1 further comprising a processor configured to determine, based on indications provided by the multi-element detector, whether an inked portion of the ink ribbon is within the field of view, wherein the inked portion is black ink.
11. The apparatus of claim 1 further comprising a processor configured to determine, based on indications provided by the multi-element detector, whether an inked portion of the ink ribbon is within the field of view, wherein the inked portion is colored ink.
12. The apparatus of claim 1 further comprising a processor configured to determine, based on indications provided by the multi-element detector, whether an inked portion of the ink ribbon is within the field of view, wherein the inked portion is metallic ink.
13. The apparatus of claim 1 , wherein the light is infrared light.
14. The apparatus of claim 1 , wherein the multi-element detector comprises a cylindrical housing that is configured to reduce optical noise.
15. The apparatus of claim 1 further comprising a processor, wherein the processor is configured to output data representative of a determination made by the processor to a processor of the printer.
16. The apparatus of claim 1 , wherein the apparatus is configured to determine whether there is an absence of the ink ribbon in the field of view without using a snap plate.
17. The apparatus of claim 1 , wherein the apparatus is implemented in a printer.