Systems for optical communication between an image forming device and a replaceable unit of the image forming device

1. A replaceable unit for an image forming apparatus, comprising:

a housing; and

at least one transmissive member positioned on an exterior of the housing for receiving optical energy from the image forming apparatus, the at least one transmissive member composed of a transmissive material that allows a fraction of the optical energy to pass through the transmissive material modifying an amount of the optical energy that leaves the at least one transmissive member relative to an amount of the optical energy received by the at least one transmissive member, the fraction of the optical energy that passes through the transmissive material relative to the amount of the optical energy received by the transmissive material defines a transmissivity percentage value of the at least one transmissive member;

wherein the transmissivity percentage value of the at least one transmissive member indicates a characteristic of the replaceable unit.

2. The replaceable unit of claim 1 , wherein a number of the at least one transmissive member positioned on the exterior of the housing indicates a characteristic of the replaceable unit.

3. The replaceable unit of claim 1 , further comprising a positioning guide on the exterior of the housing that aligns the replaceable unit when the replaceable unit is installed in the image forming device, wherein the at least one transmissive member is positioned along the positioning guide.

4. The replaceable unit of claim 3 , wherein the at least one transmissive member includes a plurality of transmissive members disposed on the positioning guide.

5. The replaceable unit of claim 4 , wherein the plurality of transmissive members are substantially of uniform width along a direction of insertion of the replaceable unit into the image forming apparatus.

6. The replaceable unit of claim 4 , wherein a number of the plurality of transmissive members on the positioning guide indicates a characteristic of the replaceable unit.

7. The replaceable unit of claim 1 , further comprising a rotatable drive element on the exterior of the housing, the at least one transmissive member being disposed on the drive element.

8. The replaceable unit of claim 1 , further comprising an end cap coupled to a longitudinal end of the housing, wherein the at least one transmissive member is disposed on the end cap.

9. The replaceable unit of claim 1 , further comprising a memory device on the housing having stored therein an electrical signature corresponding with the transmissivity percentage value of the at least one transmissive member.

10. A container for ink or toner, the container installable in an image forming device having an optical sensor, the optical sensor including a transmitter that emits optical energy along an optical path and a receiver positioned to receive the optical energy, the container comprising:

a housing having a reservoir for holding ink or toner; and

at least one transmissive member positioned on an exterior of the housing, the at least one transmissive member is unobstructed and positionable in the optical path when the container is installed in the image forming device, the at least one transmissive member is composed of a transmissive material that allows a fraction of the optical energy to pass through the transmissive material relative to an amount of the optical energy received by the transmissive material, the fraction of the optical energy that passes through the transmissive material relative to the amount of the optical energy received by the transmissive material defines a transmissivity percentage value of the at least one transmissive member;

wherein a characteristic of the container is encoded in the transmissivity percentage value of the at least one transmissive member such that the characteristic is determined by comparing the transmissivity percentage value of the at least one transmissive member with a plurality of predetermined transmissivity percentage values and a corresponding plurality of possible characteristics.

11. The container of claim 10 , further comprising a positioning guide on the exterior of the housing that aligns the container when the container is installed in the image forming device, the at least one transmissive member disposed on the positioning guide.

12. The container of claim 11 , wherein the at least one transmissive member is provided as an insert to the positioning guide.

13. The container of claim 11 , wherein the at least one transmissive member is formed integral to the positioning guide.

14. The container of claim 10 , further comprising a memory device on the housing having stored therein an electrical signature corresponding with the transmissivity percentage value of the at least one transmissive member.

15. In an image forming device in which a replaceable unit containing ink or toner is installable in the image forming device to supply ink or toner thereto for use in image formation, a system for determining at least one characteristic of the replaceable unit, the system comprising:

an optical sensor including a transmitter that emits optical energy along an optical path and a receiver positioned to receive the optical energy;

at least one transmissive member positioned on an exterior of a housing of the replaceable unit, the at least one transmissive member is positioned in the optical path when the replaceable unit is installed in the image forming device and composed of a transmissive material that allows a fraction of the optical energy to pass through the transmissive material relative to an amount of the optical energy received by the transmissive material such that the at least one transmissive member changes an amount of the optical energy received by the receiver relative to an amount of the optical energy emitted by the transmitter, the fraction of the optical energy that passes through the transmissive material relative to the amount of the optical energy received by the transmissive material defines a transmissivity percentage value of the at least one transmissive member; and

a controller communicatively coupled to the optical sensor, the controller operative to determine at least one characteristic of the replaceable unit by comparing the transmissivity percentage value of the at least one transmissive member with a plurality of predetermined transmissivity percentage values and a corresponding plurality of possible characteristics.

16. The system of claim 15 , further comprising a positioning guide extending along a lengthwise dimension of the housing corresponding to a direction of insertion thereof into the image forming device, the at least one transmissive member positioned on the positioning guide.

17. The system of claim 16 , further comprising a storage area for the replaceable unit and a loading rail running along a length of the storage area for engaging the positioning guide, wherein the optical sensor is disposed at a location on the loading rail such that the at least one transmissive member moves into the optical path when the replaceable unit is installed in the image forming device.

18. The system of claim 15 , wherein the controller is further operative to authenticate the replaceable unit based at least in part upon the determined at least one characteristic.

19. The system of claim 15 , wherein the controller is further operative to verify correct installation of the replaceable unit in the image forming device based at least in part upon the determined at least one characteristic.

20. The system of claim 15 , further comprising an independent power source coupled to at least one of the controller and the optical sensor for providing power thereto.