1. A system for providing electrophotographic latent images on a photoconductive element having a conductive stripe that is in contact with a photoconductive layer on one edge of the photoconductive element comprising:
a first corona charge device positioned to charge the photoconductive layer; and
a second corona charge device positioned to charge the conductive stripe with a charge that is opposite a charge provided by the first corona charge device.
2. The system of claim 1 having an optical imaging system between the first corona charge device and the second corona charge device.
3. The system of claim 2 having a charge toning device between the first corona charge device and the second corona charge device.
4. The system of claim 3 wherein the photoconductive element comprises an endless belt or a drum.
5. The system of claim 2 wherein the photoconductive element comprises an endless belt or a drum.
6. The system of claim 1 having a charge toning device between the first corona charge device and the second corona charge device.
7. The system of claim 6 wherein the photoconductive element comprises an endless belt or a drum.
8. The system of claim 1 wherein the photoconductive element comprises an endless belt or a drum.
9. The system of claim 1 wherein the second corona charge device is positioned between 2\u201310 mm from the conductive stripe of the photoconductive layer.
10. The system of claim 1 wherein the second corona charge device does not include the use of a shield integral to a wire in the second corona charge device.
11. A method of providing latent charge images on a photoconductive element having a photoconductive layer with a conductive stripe, the method comprising:
charging the photoconductive layer with a charge having a particular vector to form a uniform charge on the photoconductive layer; and
subsequently charging the conductive stripe with a charge having a vector that is opposite the vector of the charge on the photoconductive layer to lower the charge content on the photoconductive layer.
12. The method of claim 11 wherein a portion of the uniform charge is dissipated by exposure to radiation prior to the subsequent charging of the conductive stripe.
13. The method of claim 12 wherein the photoconductive layer is toned with an electrophotographic toner prior to the subsequent charging of the conductive stripe.
14. The method of claim 11 wherein the photoconductive layer is toned with an electrophotographic toner prior to the subsequent charging of the conductive stripe.
15. The method of claim 11 further comprising:
sensing a ground stripe voltage by
measuring the surface potential of the ground stripe at a point downstream of a second corona charging device to provide a signal,
sending the signal to an error amplifier,
comparing the measured surface potential with a reference surface potential to provide a resulting comparison,
sending the resulting comparison to a high voltage amplifier,
sending a charge to the second corona charging device of sufficient potential based upon the resulting comparison to alter the sensed ground stripe voltage in a correct vector,
and applying positive or negative ions to the ground stripe to provide a potential close to zero volts.
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 method for forming a copper-infiltrated iron powder metal article comprising:
compacting and sintering a predominantly iron powder to form an iron-base matrix comprising between about 1 and 7 weight percent nickel and about 0.1 and 1.2 weight percent phosphorus, said matrix comprising pores, and
infiltrating the pores of the iron-base matrix with a copper metal.
2. A method in accordance with claim 1 wherein the step of compacting and sintering comprises compacting a powder mixture containing between about 1 and 7 weight percent nickel and a ferro-phosphorus powder effective to produce said phosphorus in the matrix.
3. A method in accordance with claim 1 wherein the step of infiltrating is carried out concurrently sintering to form the iron-base matrix.
4. A method in accordance with claim 1 wherein the copper metal is between about 2.0 and 23 weight percent of the copper-infiltrated iron powder metal article.
5. A method for forming a copper-infiltrated iron powder metal article comprising:
compacting an iron powder mixture to form a compact, said mixture comprising between about 1 and 3 weight percent nickel powder, a ferro-phosphorus powder in an amount effective to produce a phosphorus concentration between about 0.4 and 0.9 weight percent, optionally up to about 2 weight percent molybdenum, and the balance substantially iron,
sintering the compact at a temperature effective to diffusion bond the iron powder to form a matrix and to diffuse nickel and phosphorus into the matrix, said matrix including pores; and
infiltrating a copper metal into the pores of the matrix.
6. A method in accordance with claim 5 wherein the steps of sintering the compact and infiltrating the pores with copper are carried out concurrently by heating the compact in contact with a copper metal.
7. A method in accordance with claim 5 further comprising heating the copper-infiltrated iron powder article at a temperature and for a time sufficient to anneal the matrix and improve elongation properties of the copper-infiltrated iron powder metal article.
8. A method in accordance with claim 8, wherein the copper-infiltrated iron powder article is annealed at a temperature between about 650 C. and 760 C.
9. A method in accordance with claim 5 further comprising heating the copper-infiltrated iron powder article at a temperature and for a time effective to relieve stress in the copper metal.
10. A method in accordance with claim 9, wherein the copper-infiltrated iron powder article is heated at a temperature between about 200 C. and 315 C.
11. A method in accordance with claim 5 wherein the copper metal is between about 10 and 16 weight percent of the copper-infiltrated iron powder metal article.
12. A copper-infiltrated iron powder metal article comprising:
an iron-nickel alloy matrix comprising between about 0.1 and 1.2 weight percent phosphorus, about 1 and 7 weight percent nickel, optionally up to 2 weight percent molybdenum and the balance substantially iron, said iron-base sintered powder matrix including pores, and
a copper phase disposed within the pores, wherein the copper phase is between 2 and 23 weight percent of the copper-infiltrated iron powder metal article.
13. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 12 further characterized by a tensile strength greater than about 600 MPa.
14. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 12 further characterized by an elongation between about 4 and 18 percent.
15. A copper-infiltrated iron powder metal article comprising:
an iron-nickel alloy matrix comprising between about 0.4 and 0.9 weight percent phosphorus, about 1 and 3 weight percent nickel, up to 1 weight percent molybdenum and the balance substantially iron, said iron-base sintered powder matrix including pores, and
a copper metal disposed within the pores, wherein the copper metal is between 10 and 16 weight percent of the copper-infiltrated iron powder metal article.
16. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 15 further characterized by a tensile strength between about 600 and 660 MPa.
17. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 15 further characterized by an elongation between about 4 and 18 percent.
18. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 15 wherein the copper-infiltrated iron-nickel alloy powder metal article has been annealed.
19. A copper-infiltrated iron-nickel alloy powder metal article in accordance with claim 15 wherein the copper-infiltrated iron-nickel alloy powder metal article has been heat treated to relieve stress in the copper metal.