1-19. (canceled)
20. A method of generating a phase contrast image comprising:
providing an electron microscope having a objective lens defining a back focal plane and an object plane;
imaging the back focal plane into a diffraction intermediate image plane, wherein said imaging also causes an intermediate image of the object plane to be formed;
providing a phase shifting element in or near said diffraction intermediate image plane; and,
imaging the intermediate image plane with a lens having no or no significant influence on a further imaging of the diffraction intermediate image plane.
21. The method of claim 20, wherein the imaging of the back focal plane into the diffraction intermediate image plane is enlarged.
22. The method of claim 20, further comprising adjusting a lateral position of an image of the back focal plane in the diffraction intermediate image plane relative to the phase shifting element.
23. The method of claim 20, wherein imaging the intermediate image plane further comprises imaging the intermediate image plane into an entry image plane of a projection system.
24. The method of claim 23, further comprising providing an electron beam and illuminating the object plane with the electron beam.
25. A phase contrast electron microscope comprising:
an objective lens defining a back focal plane;
a lens system forming an image of said back focal plane in a diffraction intermediate image plane;
said lens system further comprising a lens having a principle plane disposed in the vicinity of said diffraction intermediate image plane; and,
a phase shifting element arranged in or near said diffraction intermediate image plane.
26. The phase contrast electron microscope of claim 25, wherein the diffraction plane of the objective is imaged magnified into the diffraction intermediate image plane.
27. The phase contrast electron microscope of claim 26, wherein the diffraction plane of the objective is imaged into the diffraction intermediate image plane with a magnification factor between two times and ten times.
28. The phase contrast electron microscope of claim 25, wherein said objective lens defines an entrance image plane, further comprising a projection system downstream of said lens system, said projection system generating a final image of said entrance image plane.
29. The phase contrast electron microscope of claim 25, further comprising a beam deflection system for adjusting the lateral position of the image of the back focal plane relative to the phase shifting element.
30. The phase contrast electron microscope of claim 25, wherein the deflection system is a double deflection system which deflects the electron beam in two mutually perpendicular directions.
31. The phase contrast electron microscope of claim 25, further comprising:
an electron source; and,
a condenser system having electron lenses for forming an electron beam from electrons emanating from said electron source.
32. The phase contrast electron microscope of claim 31, wherein said condenser system illuminates an object plane of said objective by said electron beam.
33. The phase contrast electron microscope of claim 25, wherein said objective lens defines an entrance image plane, further comprising:
a projection system downstream of said lens system generating a final image of said entrance image plane;
an electron source;
a condenser system having electron lenses for forming an electron beam from electrons emanating from said electron source; and,
wherein said condenser system illuminates an object plane of said objective with said electron beam.
34. The phase contrast electron microscope of claim 33, wherein the diffraction plane of the objective is imaged magnified into the diffraction intermediate image plane.
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. In a dual engine color printer having a first print engine and a second print engine, each engine comprising a single multi-color printing drum set, a scheduling method for imbalanced dual sided printing of a plurality of sheets in a print job, in which a first side of each sheet of said plurality requires a first set of separations and a second side thereof requires a second set of separations, said first and second sets having different numbers of separations, the method comprising:
feeding respective ones of said plurality of sheets in sequence between said print engines, and
alternating for successive sheets between printing said first set at said first engine and said second set at said second engine on the one hand and printing said second set at said first engine and said first set at said second engine on the other hand.
2. The method of claim 1, wherein said feeding and alternating comprises repetitively until said print job is complete:
feeding one of said plurality of sheets to said first engine, and printing said first number of separations on a first side thereof;
subsequently, feeding said one sheet to said second engine, and printing said second number of separations on a second side thereof;
simultaneously with said feeding of said first sheet to said second engine, feeding a following one of said plurality of sheets to said first engine, and printing said second number of separations on a first side thereof; and
subsequently feeding said following sheet to said second engine, and printing said first number of separations on a second side thereof.
3. The method of claim 2, further comprising inverting respective alternate sheets for output.
4. The method of claim 2, further comprising feeding respective alternate sheets to alternate output sites.
5. The method of claim 1, further comprising looking ahead to succeeding print operations to spot imbalances in said succeeding print operations and applying or not applying said feeding and alternating accordingly.
6. A controller for a dual engine color printing machine, the dual engine printing machine comprising a first color print engine and a second color print engine, each engine comprising a single multi-color printing drum, the controller having a mode for imbalanced dual sided printing, said imbalanced dual sided printing being a case in which a first side of each sheet of said plurality requires a first set of separations and a second side thereof requires a second set of separations, said first and second sets having different numbers of separations, the mode comprising:
a control operation applied to a sheet feeding mechanism for feeding respective ones of said plurality of sheets in sequence between said print engines, and
a control operation applied to said engines for alternating for successive sheets between printing said first set at said first engine and said second set at said second engine on the one hand and printing said second set at said first engine and said first set at said second engine on the other hand.
7. The controller of claim 6, wherein said control operation of feeding and alternating applied to said engines comprises repetitively until said print job is complete:
feeding one of said plurality of sheets to said first engine, and printing said first number of separations on a first side thereof;
subsequently, feeding said one sheet to said second engine, and printing said second number of separations on a second side thereof;
simultaneously with said feeding of said first sheet to said second engine, feeding a following one of said plurality of sheets to said first engine, and printing said second number of separations on a first side thereof; and
subsequently feeding said following sheet to said second engine, and printing said first number of separations on a second side thereof.
8. The controller of claim 6, further operable to provide an output feed signal to control output feeding of said sheets such as to invert alternate sheets between printing and output.
9. The controller of claim 6, further operable to provide an output feed signal to control output feeding of said sheets to deliver alternate sheets to different output sites.
10. The controller of claim 6, further comprising a look-ahead function for looking ahead to successive print operations to determine a presence or absence of imbalances therein and to apply or not apply said mode accordingly.
11. A dual engine color printing machine comprising a first color print engine and a second color print engine, each engine comprising a single multi-color printing drum, and a controller, the controller having a mode for imbalanced dual sided printing, said imbalanced dual sided printing being a case in which a first side of each sheet of said plurality requires a first set of separations and a second side thereof requires a second set of separations, said first and second sets having different numbers of separations, the mode comprising:
a control operation applied to a sheet feeding mechanism for feeding respective ones of said plurality of sheets in sequence between said print engines, and
a control operation applied to said engines for alternating for successive sheets between printing said first set at said first engine and said second set at said second engine on the one hand and printing said second set at said first engine and said first set at said second engine on the other hand.