1. An imaging apparatus comprising:
a media carrier;
at least two exposure heads spaced apart from one another, each exposure head disposed to image a portion of a single sheet of media secured on the media carrier, or one of at least two sheets of media secured on the media carrier; and
an adjustable mechanism for moving the exposure heads relative to each other to change a spacing therebetween wherein the adjustable mechanism comprises a heater located to controllably heat a rigid spacer coupling the exposure heads.
2. An imaging apparatus, comprising:
a media carrier;
at least two exposure heads spaced apart from one another, each exposure head disposed to image a portion of a single sheet of media secured on the media carrier, or one of at least two sheets of media secured on the media carrier;
an adjustable mechanism for moving the exposure heads relative to each other to change a spacing therebetween while each exposure head is imaging;
wherein the media carrier is a cylindrical drum and the media is secured to an external surface of the drum; and
wherein each exposure head is traversed by a leadscrew nut coupled to the exposure head and located on a common leadscrew and the adjustable mechanism comprises a coupling between at least one of the leadscrew nuts and the associated exposure head capable of being displaced relative to the other exposure head.
3. An apparatus according to claim 2, wherein the at least one of the leadscrew nuts is displaced by rotating the at least one of the leadscrew nuts on the common leadscrew.
4. An apparatus according to claim 3, comprising an auxiliary motor for rotating the at least one of the leadscrew nuts in response to signals provided by a controller.
5. An apparatus according to claim 2, wherein each of the leadscrew nuts is rotatable and the common leadscrew is held fixed.
6. An imaging apparatus, comprising:
a media carrier;
at least two exposure heads spaced apart from one another, each exposure head disposed to image a portion of a single sheet of media secured on the media carrier, or one of at least two sheets of media secured on the media carrier;
an adjustable mechanism for moving the exposure heads relative to each other to change a spacing therebetween during imaging;
wherein the media carrier is a cylindrical drum and the media is secured to an external surface of the drum; and
a speed controller connected to allow a traverse speed of at least one of the exposure heads to be controlled sufficiently precisely to adjust a position of a last channel to within less than one beam width.
7. An imaging apparatus, comprising:
a media carrier;
at least two exposure heads spaced apart from one another, each exposure head disposed to image a portion of a single sheet of media secured on the media carrier, or one of at least two sheets of media secured on the media carrier;
an adjustable mechanism for moving the exposure heads relative to each other to change a spacing therebetween while each exposure head is moving concurrently; and
wherein each exposure head is disposed to image along a scan path, and the adjustable mechanism is disposed to change the spacing along a direction substantially perpendicular to the scan path.
8. A method of imaging with at least two exposure heads, the method comprising:
loading at least one sheet of media on a media carrier;
measuring a temperature of an adjustable mechanism for moving the exposure heads relative to each other to change a spacing therebetween;
adjusting the spacing between the exposure heads in accordance with the measured temperature; and
imaging with each exposure head, a portion of a single sheet of media secured on the media carrier, or one of at least two sheets of media secured on the media carrier.
9. A method according to claim 8, wherein in the event of a failure of one of the at least two exposure heads the imaging of any number and size of media is completed by another one of the exposure heads.
10. A method according to claim 8, wherein the relative spacing between the two or more exposure heads is adjusted by aligning each of the exposure heads to a target.
11. A method according to claim 8, wherein each exposure head has at least one imaging beam, the method further comprising determining the pointing location of the imaging beam and adjusting the spacing between the exposure heads in accordance with the pointing location of the imaging beam.
12. A method according to claim 8, comprising joining the portion imaged by each exposure head to form a unitary image on the single sheet of media secured on the media carrier.
13. A method according to claim 12, wherein the joining comprises at least partially overlapping the portions imaged by each exposure head.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A catalyst deterioration detecting apparatus for an internal combustion engine, comprising:
a controller that:
detects an amount of oxygen stored in an upstream catalyst and a separate amount of oxygen stored in a downstream catalyst;
controls the amount of stored oxygen in the upstream catalyst by controlling an air-fuel ratio of gasses that flow into the catalyst based on said detected amounts;
detects an oxygen storage capacity of the upstream catalyst based on said detected amount of stored oxygen in the upstream catalyst; and
determines degradation of said upstream catalyst based on said detected oxygen storage capacity of the upstream catalyst.
2. The apparatus of claim 1 further comprising an upstream exhaust gas oxygen sensor located upstream of said upstream catalyst, and a downstream exhaust gas oxygen sensor located between said upstream catalyst and said downstream catalyst.
3. The apparatus of claim 2 wherein said controller further detects said amount of oxygen stored in said upstream catalyst and said amount of oxygen stored in said downstream catalyst based on said upstream and downstream sensors.
4. A catalyst deterioration detecting apparatus for an internal combustion engine, comprising:
a controller that:
detects an amount of oxygen stored in an upstream catalyst and an amount of oxygen stored in a downstream catalyst;
controls the amount of stored oxygen in the upstream catalyst by controlling an air-fuel ratio of gasses that flow into the upstream catalyst;
detects an oxygen storage capacity of the upstream catalyst based on said detected amount of stored oxygen in the upstream catalyst during vehicle operation;
determines degradation of said upstream catalyst based on said detected oxygen storage capacity;
an upstream exhaust gas oxygen sensor located upstream of said upstream catalyst: and
a downstream exhaust gas oxygen sensor located between said upstream catalyst and said downstream catalyst.
5. The apparatus of claim 4 wherein said controller further detects said amount of oxygen stored in said upstream catalyst and said amount of oxygen stored in said downstream catalyst based on said upstream and downstream sensors.
6. A catalyst deterioration detecting apparatus for an internal combustion engine, comprising:
a controller that:
detects an amount of oxygen stored in an upstream catalyst and an amount of oxygen stored in a downstream catalyst;
controls the amount of stored oxygen in the upstream catalyst by controlling an air-fuel ratio of gasses that flow into the catalyst; and
detects an oxygen storage capacity of the upstream catalyst based on operation where the engine is operated lean to fill the upstream catalyst with oxygen and then the engine is operated rich;
determines degradation of said upstream catalyst based on said detected oxygen storage capacity;
an upstream exhaust gas oxygen sensor located upstream of said upstream catalyst; and
a downstream exhaust gas oxygen sensor located between said upstream catalyst and said downstream catalyst.
7. The apparatus of claim 6 wherein said controller further detects said amount of oxygen stored in said upstream catalyst and said amount of oxygen stored in said downstream catalyst based on said upstream and downstream sensors.
8. The apparatus of claim 6 wherein said lean operation is ended based on said downstream sensor.
9. A catalyst deterioration detecting apparatus for an internal combustion engine, comprising:
a controller that:
detects an amount of oxygen stored in an upstream catalyst and a separate amount of oxygen stored in a downstream catalyst;
controls the amount of stored oxygen in the upstream catalyst by controlling an air-fuel ratio of gasses that flow into the catalyst; and
detects an oxygen storage capacity of the upstream catalyst based on operation where the engine is operated rich to deplete oxygen in the upstream catalyst and then the engine is operated lean; and
determines degradation of said upstream catalyst based on said detected oxygen storage capacity of said upstream catalyst.
10. The apparatus of claim 9 further comprising an upstream exhaust gas oxygen sensor located upstream of said upstream catalyst, and a downstream exhaust gas oxygen sensor located between said upstream catalyst and said downstream catalyst.
11. The apparatus of claim 10 wherein said controller further detects said amount of oxygen stored in said upstream catalyst and said amount of oxygen stored in said downstream catalyst based on said upstream and downstream sensors.
12. The apparatus of claim 9 wherein said rich operation is ended based on said downstream sensor.
13. A method for detecting deterioration of a catalyst for an internal combustion engine, the method comprising:
detecting an amount of stored oxygen in the catalyst;
controlling said amount of stored oxygen in the catalyst by adjusting air-fuel ratio of the engine based on said detected amount of stored oxygen in the catalyst;
determining degradation of the catalyst based on said detected amount of stored oxygen in the catalyst, wherein said determining degradation includes determing a level of degradation.
14. The method of claim 13 wherein said control is based on an error between a set point amount of oxygen storage and said detected amount of stored oxygen in the catalyst.
15. The method of claim 14 wherein said set point is at a location in an exhaust system, said location moved based on engine operating conditions.
16. The method of claim 14 wherein set point location is moved along a length of the exhaust system.
17. The method of claim 14 wherein set point location is moved between different positions in a catalyst brick.
18. The method of claim 14 wherein set point location is moved between different catalysts.
19. The method of claim 14 wherein set point location is moved between different catalyst bricks.
20. The method of claim 13 wherein said adjusting air-fuel ratio of the engine includes adjusting injected fuel that enters the engine combustion chamber.
21. The method of claim 13 wherein said determining degradation includes determining a rate of degradation.
22. A method for detecting deterioration of a catalyst for an internal combustion engine, the method comprising:
detecting an amount of stored oxygen in the catalyst;
controlling said amount of stored oxygen in the catalyst by adjusting air-fuel ratio of the engine based on said detected amount of stored oxygen in the catalyst;
detecting an oxygen storage capacity of the catalyst based on said detected amount of stored oxygen in the catalyst;
determining degradation of the catalyst based on said detected oxygen storage capacity of the catalyst; and
wherein said control is based on an error between a set point amount of oxygen storage and said detected amount of stored oxygen in the catalyst.
23. The method of claim 22 wherein said set point is at a location in an exhaust system, said location moved based on engine operating conditions.
24. The method of claim 22 wherein set point location is moved along a length of the exhaust system.
25. The method of claim 22 wherein set point location is moved between different positions in a catalyst brick.
26. The method of claim 22 wherein set point location is moved between different catalysts.
27. The method of claim 22 wherein set point location is moved between different catalyst bricks.
28. The method of claim 22 wherein said adjusting air-fuel ratio of the engine includes adjusting injected fuel that enters the engine combustion chamber.
29. The method of claim 22 wherein said determining degradation includes determining a level of degradation.
30. The method of claim 22 wherein said determining degradation includes determining a rate of degradation.