All The Claims

1. A quartz glass comprising a region where a concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more.
2. The quartz glass according to claim 1, wherein said concentration of E center is in the range of from 31019 cm3 to 11022 cm3.
3. The quartz glass according to claim 1, wherein said concentration of E center is in the range of from 71019 cm3 to 11022 cm3.
4. A method of manufacturing a quartz glass which comprises the steps of;
forming an initial quartz glass by melting and quenching a raw material for quartz glass; and
implanting therein an ion, which is capable of entering into an SiO2 network of the initial quartz glass and substantially incapable of externally diffusing, to increase a concentration of E center in at least part of the initial quartz glass.
5. The method of manufacturing a quartz glass according to claim 4, wherein said ion is selected from the group consisting of silicon, nitrogen, carbon and aluminum.
6. The method of manufacturing a quartz glass according to claim 4, wherein a dosage of said ion is 51014 cm2 or more.
7. The method of manufacturing a quartz glass according to claim 6, wherein a dosage of said ion is in the range of from 11015 cm2 or more.
8. The method of manufacturing a quartz glass according to claim 6, wherein a dosage of said ion is in the range of from 11015 cm2 to 11016 cm2.
9. The method of manufacturing a quartz glass according to claim 4, wherein said concentration of E center in said ion-implantation region as measured by means of an electron spin resonance analysis is 31019 cm3 or more.
10. A method of manufacturing a quartz glass which comprises the steps of;
mixing 0.01 to 0.1% by weight of silicon into a raw material for quartz glass;
melting the raw material for quartz glass mixed with said silicon to obtain a melt; and
quenching said melt.
11. The method of manufacturing a quartz glass according to claim 10, wherein said concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more.
12. A method of manufacturing a quartz glass which comprises the steps of;
melting a raw material for quartz glass to obtain a melt;
quenching said melt thereby to form an initial quartz glass; and
irradiating ultraviolet-rays to said initial quartz glass.
13. The method of manufacturing a quartz glass according to claim 12, wherein said concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more.
14. A method of manufacturing a quartz glass which comprises the steps of;
melting a raw material for quartz glass to obtain a melt;
quenching said melt thereby to form an initial quartz glass; and
giving an abrasion damage to a surface of said initial quartz glass by applying a sand blast to said surface of initial quartz glass.
15. The method of manufacturing a quartz glass according to claim 14, wherein said concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more.
16. A heat treating apparatus comprising;
a furnace tube formed of quartz glass comprising a region where a concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more; and
heating means mounted around said furnace tube.
17. The heat treating apparatus according to claim 16, which further comprises ultraviolet-irradiating means for irradiating ultraviolet ray onto said furnace tube.
18. A method of heat-treating a semiconductor wafer, which comprises the steps of;
arranging the semiconductor wafer in a furnace tube formed of quartz glass comprising a region where a concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more; and
heat-treating the semiconductor wafer while flowing a non-oxidizing gas in such a manner that the non-oxidizing gas contacts directly with an outer wall of said furnace tube.
19. The method of heat-treating a semiconductor wafer according to claim 18, wherein a concentration of oxidizing gas that is included in said non-oxidizing gas is 100 ppm or less.
20. A method of heat-treating a semiconductor wafer, which comprises the steps of;
arranging the semiconductor wafer in a furnace tube formed of quartz glass comprising a region where a concentration of E center as measured by means of an electron spin resonance analysis is 31019 cm3 or more; and
heat-treating the semiconductor wafer while irradiating ultraviolet rays onto said furnace tube.
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 providing a service to a subscriber in a network, comprising the steps of:
a) providing a network information of the subscriber to a service provider;
b) generating a service message on the basis of the provided network information; and
c) transmitting the service message to the subscriber.
2. A method according to claim 1, wherein said network information relates to at least one of an identity, a location, an address, and an operating state of a mobile station of the subscriber in a cellular network.
3. A method according to claim 1 or 2, wherein said service message is a local advertisement.
4. A method according to claim 1 or 2, wherein said service message is a header of an unread mail stored in a mail server.
5. A method according to claim 1 or 2, wherein said service message is a stock price change.
6. A method according to any one of claims 2 to 5, wherein said service message is transmitted when said mobile station is reachable according to the network information.
7. A method according to any one of claims 2 to 6, wherein the network information of the subscriber is transmitted by a network operator to the provider of the external message in dependence on a predetermined subscriber condition.
8. A method according to claim 7, wherein said predetermined subscriber condition is a request from the subscriber.
9. A method according to claim 8, wherein said request is set by the mobile station.
10. A method according to claim 8, wherein said request is set by a network operator.
11. A method according to claim 8 or 9, wherein a network operator receives the request including a service provider address, retrieves location coordinates of the subscriber on the basis of a cell identification, and transmits the location coordinates to the service provider using the received address.
12. A method according to any one of claims 2 to 11, wherein the network information of the subscriber is transmitted in a header of a packet transmitted by the mobile station.
13. A method according to claim 12, wherein the network information is inserted by a network element in a second packet which encapsulates the packet transmitted by the mobile station.
14. A method according to any one of claims 1 to 6, wherein the network information of the subscriber is stored in a storing means in dependence on a predetermined subscriber condition, and wherein said storage means is accessible to the service provider.
15. A method according to claim 14, wherein the service provider reads the storing means by using a predetermined key relating to the subscriber.
16. A method according to claim 14 or 15, wherein said predetermined subscriber condition is a request from the subscriber.
17. A method according to claim 7, 14 or 15, wherein said predetermined subscriber condition is a subscription parameter of the subscriber.
18. A method according to claim 7, 14 or 15, wherein said predetermined subscriber condition is an activation of a predetermined supplementary service.
19. A method according to claim 7, 14 or 15, wherein said predetermined subscriber condition is the fact that the subscriber is located in his home area.
20. A system for providing a service to a subscriber in a network, comprising:
a) providing means (7) for providing a network information of the subscriber to a service provider (5); and
b) control means (6) for controlling the provision of the network information to the service provider (5) in dependence on a predetermined subscriber condition.
21. A system according to claim 20, wherein the network information relates to at least one of an identity, a location and an operating state of a mobile station (1) of the subscriber in a cellular network.
22. A system according to claim 21, further comprising a data base for converting a cell identification of the mobile station (1) into allocation thereof.
23. A system according to any one of claims 20 to 22, wherein the providing means (7) comprises a transmitting means fortransmitting the network information of the subscriber to the service provider (5), wherein the control means (6) controls the transmitting operation in dependence on the predetermined subscriber condition.
24. A system according to any one of claims 20 to 22, wherein the providing means (7) comprises a storing means in which the network information of the subscriber is stored and which is accessible to the service provider (5), wherein the control means (6) controls the storing operation in dependence on the predetermined subscriber condition.
25. A system according to any one of claims 20 to 24, wherein said predetermined subscriber condition is a request from the subscriber.
26. A system according to any one of claims 20 to 24, wherein said predetermined subscriber condition is a subscription parameter of the subscriber.
27. A system according to any one of claims 20 to 24, wherein said predetermined subscriber condition is an activation of a predetermined supplementary service.
28. A system according to any one of claims 20 to 24, wherein said predetermined subscriber condition is the fact that the subscriber is located in his home area.

1. An internal medical device comprising: (a) electrodes that are adapted to have tissue of a subject positioned between them upon deployment of said medical device within said subject, (b) a power source adapted to apply a voltage across said electrodes, thereby generating an electric field having a vector that is directed into said tissue, and (c) a therapeutic agent source adapted to introduce a therapeutic agent into said electric field.
2. The internal medical device of claim 1, wherein said medical device is selected from catheters, grafts, stents, balloons, chronic total occlusion devices, aneurysm treatment devices, angioplasty devices, filters, atrial septal defect closure devices, devices for sealing arterial punctures, and defibrillation devices.
3. The internal medical device of claim 1, wherein said medical device is selected from medical devices that provide new or enhanced paths for flow of bodily fluids subsequent to implantation or insertion and medical devices that obstruct flow of bodily fluids subsequent to implantation or insertion.
4. The internal medical device of claim 1, wherein said power source is adapted to apply a voltage that is sufficient to cause electroporation within said tissue.
5. The internal medical device of claim 1, wherein at least one of said electrodes is configured to pierce or deflect said tissue upon deployment.
6. The internal medical device of claim 1, wherein said device comprises a plurality of electrodes that are configured to pierce or deflect said tissue upon deployment.
7. The internal medical device of claim 6, wherein said plurality of electrodes configured to pierce said tissue are selected from blades, needles and a combination thereof.
8. The internal medical device of claim 7, wherein said needles are selected from metal microneedles, metal alloy microneedles, conductive nanotubes, conductive nanowires, and combinations of the same.
9. The internal medical device of claim 6, wherein said electrodes that are configured to pierce or deflect said tissue upon deployment are disposed at an outer surface of an expandable device.
10. The internal medical device of claim 1, wherein at least a portion of said therapeutic agent source is positioned within said electric field.
11. The internal medical device of claim 10, wherein said therapeutic agent source comprises a polymeric region comprising said therapeutic agent and a polymer.
12. The internal medical device of claim 10, wherein said therapeutic agent source comprises a polymeric region comprising a charged therapeutic agent, and wherein said power source is adapted to apply a voltage that is sufficient to cause enhanced retention of said charged therapeutic agent, enhanced delivery of said charged therapeutic agent, or both.
13. The internal medical device of claim 12, wherein said power source is further adapted to apply a voltage that is sufficient to cause electroporation within said tissue.
14. The internal medical device of claim 12, wherein said medical device comprises a plurality of said polymeric regions.
15. The internal medical device of claim 14, wherein said medical device comprises a first polymeric region that comprises a first charged therapeutic agent having a positive charge and a second polymeric region that comprises a second charged therapeutic agent having a negative charge.
16. The internal medical device of claim 12, wherein said polymeric region comprises a polymer selected from a polyether, a polyelectrolyte, an electrically conductive polymer, and a combination thereof.
17. The internal medical device of claim 12, wherein said polymeric region comprises a polymer selected from a homopolymer, a random copolymer, a periodic copolymer, a block copolymer and a combination thereof.
18. The internal medical device of claim 12, wherein said charged therapeutic agent is selected from a therapeutic agent that is inherently charged, a therapeutic agent that is covalently attached to a charged molecule, a therapeutic agent that is non-covalently attached to a charged molecule, a therapeutic agent that is attached to or encapsulated within a charged particle, and a combination thereof.
19. The internal medical device of claim 12, wherein said charged therapeutic agent comprises charged paclitaxel.
20. The internal medical device of claim 12, wherein said charged therapeutic agent comprises a polyelectrolyte chain.
21. The internal medical device of claim 12, wherein said polymeric region is disposed over a polymeric substrate.
22. The internal medical device of claim 21, wherein said polymeric substrate comprises a first polymer comprising a polyether chain, wherein said polymeric region comprises a second polymer comprising a polyether chain, and wherein said first and second polymers may be the same or different.
23. The internal medical device of claim 21, wherein said polymeric substrate comprises a first polymer comprising a polyamide chain, wherein said polymeric region comprises a second polymer comprising a polyamide chain, and wherein said first and second polymers may be the same or different.
24. The internal medical device of claim 21, wherein said polymeric substrate comprises a block copolymer that comprises polyether and polyamide chains, and wherein said polymeric region comprises an ion-conductive polymer that comprises a chain selected from a polyether chain, a polyamide chain, and a combination thereof.
25. The internal medical device of claim 24, wherein said block copolymer comprises polytetramethylene oxide and nylon 12 chains.
26. The internal medical device of claim 24, wherein said ion-conductive polymer comprises a chain selected from a poly(ethylene oxide) chain, a poly(amino acid) polyelectrolyte chain, and a combination thereof.
27. An internal drug delivery device comprising: (a) an ion-conductive polymeric region comprising a polymer and a charged therapeutic agent; (b) electrodes and (c) a source of electrical power for applying a voltage across said electrodes.
28. The internal medical device of claim 27, wherein said medical device is selected from catheters, grafts, stents, balloons, chronic total occlusion devices, aneurysm treatment devices, filters, angioplasty devices, atrial septal defect closure devices, devices for sealing arterial punctures, and defibrillation devices.
29. The internal medical device of claim 27, wherein said medical device is selected from medical devices that provide new or enhanced paths for flow of bodily fluids subsequent to implantation or insertion and medical devices that obstruct flow of bodily fluids subsequent to implantation or insertion.
30. The internal medical device of claim 27, wherein said power source is adapted to apply a voltage that is sufficient to cause electroporation within said tissue.
31. The internal medical device of claim 27, wherein said power source is adapted to apply a voltage that is sufficient to cause enhanced retention of said charged therapeutic agent, enhanced delivery of said charged therapeutic agent, or both.
32. The internal medical device of claim 27, wherein said medical device comprises a plurality of said ion-conductive polymeric regions.
33. The internal medical device of claim 27, wherein said polymer is selected from a polyether and a polyelectrolyte.
34. The internal medical device of claim 27, wherein said polymer is selected from a homopolymer, a random copolymer, a periodic copolymer, and a block copolymer.
35. The internal medical device of claim 27, wherein said ion-conductive polymeric region comprises an inorganic phase.
36. The internal medical device of claim 27, wherein said charged therapeutic agent is selected from a therapeutic agent that is inherently charged, a therapeutic agent that is covalently attached to a charged molecule, a therapeutic agent that is non-covalently attached to a charged molecule, a therapeutic agent that is attached to or encapsulated within a charged particle, and a combination thereof.
37. The internal medical device of claim 27, wherein said charged therapeutic agent comprises charged paclitaxel.
38. The internal medical device of claim 27, wherein said charged therapeutic agent comprises a polyelectrolyte chain.
39. The internal medical device of claim 27, wherein said ion-conductive polymeric region is disposed over a polymeric substrate.
40. The internal medical device of claim 39, wherein said polymeric substrate comprises a first polymer comprising a polyether chain, wherein said ion-conductive polymeric region comprises a second polymer comprising a polyether chain, and wherein said first and second polymers may be the same or different.
41. The internal medical device of claim 39, wherein said polymeric substrate comprises a first polymer comprising a polyamide chain, wherein said ion-conductive polymeric region comprises a second polymer comprising a polyamide chain, and wherein said first and second polymers may be the same or different.
42. The internal medical device of claim 39, wherein said polymeric substrate comprises a block copolymer that comprises polyether and polyamide chains, and wherein said ion-conductive polymeric region comprises an ion-conductive polymer that comprises a chain selected from a polyether chain, a polyamide chain, and a combination thereof.
43. The internal medical device of claim 42, wherein said block copolymer comprises polytetramethylene oxide and nylon-12 chains.
44. The internal medical device of claim 42, wherein said ion-conductive polymer comprises a chain selected from a poly(ethylene oxide) chain, a poly(amino acid) polyelectrolyte chain, and a combination thereof.
45. The internal medical device of claim 27, wherein said ion-conductive polymeric region comprises an ionic liquid.
46. An internal drug delivery device comprising: (a) a polymeric region comprising an electrically conductive polymer and a charged therapeutic agent; (b) electrodes and (c) a source of electrical power for applying a voltage across said electrodes, said voltage being sufficient to cause electroporation in tissue adjacent to said device.
47. The internal medical device of claim 46, wherein said polymeric region comprises a conductive polymer selected from polypyrrole and its derivatives, polyaniline and its derivatives, polythiophene and its derivatives, poly(p-phenylene vinylene) and its derivatives, polysulfone and its derivatives, polyacetylene and its derivatives, and combinations thereof.
48. The internal medical device of claim 46, wherein said polymeric region comprises substituted polypyrrole, unsubstituted polypyrrole, or a combination thereof.
49. The internal medical device of claim 46, wherein said device is selected from catheters, grafts, stents, balloons, chronic total occlusion devices, aneurysm treatment devices, filters, angioplasty devices, atrial septal defect closure devices, devices for sealing arterial punctures, and defibrillation devices.
50. The internal medical device of claim 46, wherein said medical device is selected from medical devices that provide new or enhanced paths for flow of bodily fluids subsequent to implantation or insertion and medical devices that obstruct flow of bodily fluids subsequent to implantation or insertion.
51. The internal medical device of claim 46, wherein said polymeric region is disposed over a polymeric substrate.
52. The internal medical device of claim 51, wherein said polymeric substrate comprises a block copolymer that comprises polyether and polyamide chains, and wherein said polymeric region comprises substituted polypyrrole, unsubstituted polypyrrole, or a combination thereof.
53. The internal medical device of claim 51, wherein a first electrode is disposed between said polymeric substrate and said polymeric region, and wherein a second electrode is provided beyond said polymeric region.
54. The internal medical device of claim 51, wherein said polymeric substrate is a balloon.

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. An image forming apparatus comprising:
a transfer unit that transfers onto a transfer medium an image that is formed on a photosensitive medium;
a power supply unit that provides a transfer power to the transfer unit; and
a transfer power control unit that controls the transfer power that is provided to the transfer unit by the power supply unit,
wherein the transfer power control unit sets as a target voltage an output voltage of the power supply unit that is measured by supplying an initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and controls the power supply unit to apply the set target voltage to the transfer unit by controlling a transfer current that is supplied to the transfer unit from the power supply unit while an image is being transferred onto the transfer medium based on a value of a feedback correction rate.
2. The image forming apparatus of claim 1, wherein the transfer power control unit calculates a system load of the image forming apparatus by using an output voltage of the power supply unit that is measured when the power supply unit supplies a constant current to the transfer unit and determines the initial transfer current based on the calculated system load.
3. The image forming apparatus of claim 1, wherein the transfer power control unit comprises:
a voltage measurement unit that measures an output voltage of the power supply unit, and
a transfer current control unit that controls a transfer current that is supplied to the transfer unit by the power supply unit according to the output voltage of the power supply unit that is measured by the voltage measurement unit.
4. The image forming apparatus of claim 3, wherein the transfer current control unit controls the transfer current that is supplied to the transfer unit by the power supply unit so that the output voltage of the power supply unit is maintained as the target voltage while an image is being transferred onto the transfer medium.
5. The image forming apparatus of claim 4, wherein the transfer current control unit calculates the feedback correction rate by using an output voltage of the power supply unit that is measured while an image is being transferred onto the transfer medium and the target voltage, and, if the feedback correction rate is beyond a certain range, sets as a new transfer current a value obtained by adding an integer part of a value obtained by multiplying an existing transfer current by the feedback correction rate to the existing transfer current.
6. The image forming apparatus of claim 5, wherein the transfer current control unit determines as the feedback correction rate a result value obtained such that a value obtained by subtracting the output voltage of the power supply unit that is measured while the image is being transferred from the target voltage is divided by a value obtained by adding the target voltage and the output voltage of the power supply unit that is measured while the image is being transferred and the obtained value is then multiplied by a certain constant.
7. The image forming apparatus of claim 6, wherein the transfer current control unit controls a degree of feedback control by adjusting the certain constant.
8. An image forming apparatus comprising:
a transfer unit that transfers onto a transfer medium an image that is formed on a photosensitive medium;
a power supply unit that provides a transfer power to the transfer unit; and
a transfer power control unit that controls the transfer power that is provided to the transfer unit by the power supply unit,
wherein the transfer power control unit sets as a target voltage an output voltage of the power supply unit that is measured by supplying an initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and controls the power supply unit to apply the set target voltage to the transfer unit while an image is being transferred onto the transfer medium,
wherein the transfer power control unit measures an output voltage of the power supply unit a predetermined number of times while the power supply unit supplies the initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and then sets an average of the measured output voltage values as a target voltage.
9. An image forming apparatus comprising:
a transfer unit that transfers onto a transfer medium an image that is formed on a photosensitive medium;
a power supply unit that provides a transfer power to the transfer unit; and
a transfer power control unit that controls the transfer power that is provided to the transfer unit by the power supply unit,
wherein the transfer power control unit sets as a target voltage an output voltage of the power supply unit that is measured by supplying an initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and controls the power supply unit to apply the set target voltage to the transfer unit while an image is being transferred onto the transfer medium,
wherein the transfer power control unit sets the target voltage in a period from the time after the transfer medium enters the transfer unit to the time before an image is transferred onto the transfer medium.
10. A method of controlling a transfer power of an image forming apparatus that comprises a transfer unit that transfers an image onto a transfer medium and a power supply unit that provides a transfer power to the transfer unit, the method comprising:
determining an initial transfer current;
setting as a target voltage an output voltage of the power supply unit that is measured when the power supply unit supplies the determined initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium; and
transferring an image onto the transfer medium by applying the target voltage to the transfer unit by controlling transfer current that is supplied to the transfer unit based on a value of a feedback correction rate.
11. The method of claim 10, wherein the determining comprises calculating a system load of the image forming apparatus by using an output voltage of the power supply unit that is measured when the power supply unit supplies a constant current to the transfer unit and determines the initial transfer current based on the calculated system load.
12. The method of claim 10, wherein the transferring comprises:
measuring an output voltage of the power supply unit while an image is being transferred onto the transfer medium by supplying a transfer current to the transfer unit by the power supply unit, and
controlling the transfer current that is supplied to the transfer unit by the power supply unit so that the output voltage of the power supply unit that is measured while the image is being transferred is maintained as the target voltage.
13. The method of claim 12, wherein the controlling comprises calculating the feedback correction rate by using the output voltage of the power supply unit that is measured while an image is being transferred and the target voltage, and, if the feedback correction rate is beyond a certain range, setting as a new transfer current a value obtained by adding an integer part of a value obtained by multiplying an existing transfer current by the feedback correction rate to the existing transfer current.
14. The method of claim 13, wherein the calculating comprises determining as the feedback correction rate a result value obtained such that a value obtained by subtracting the output voltage of the power supply unit that is measured while the image is being transferred from the target voltage is divided by a value obtained by adding the target voltage and the output voltage of the power supply unit that is measured while the image is being transferred and the obtained value is then multiplied by a certain constant.
15. The method of claim 14, wherein the certain constant is adjusted to control a degree of feedback control.
16. A method of controlling a transfer power of an image forming apparatus that comprises a transfer unit that transfers an image onto a transfer medium and a power supply unit that provides a transfer power to the transfer unit, the method comprising:
determining an initial transfer current;
setting as a target voltage an output voltage of the power supply unit that is measured when the power supply unit supplies the determined initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium; and
transferring an image onto the transfer medium by applying the target voltage to the transfer unit,
wherein the setting comprises measuring an output voltage of the power supply unit a predetermined number of times while the power supply unit supplies the initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium and then setting an average of the measured output voltage values as a target voltage.
17. A method of controlling a transfer power of an image forming apparatus that comprises a transfer unit that transfers an image onto a transfer medium and a power supply unit that provides a transfer power to the transfer unit, the method comprising:
determining an initial transfer current setting as a target voltage an output voltage of the power supply unit that is measured when the power supply unit supplies the determined initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium; and
transferring an image onto the transfer medium by applying the target voltage to the transfer unit,
wherein the predetermined certain period is a period from the time after the transfer medium enters the transfer unit to the time before an image is transferred onto the transfer medium.
18. A non-transitory computer-readable recording medium that records a program for executing a method on a computer of controlling a transfer power of an image forming apparatus that comprises a transfer unit that transfers an image onto a transfer medium and a power supply unit that provides a transfer power to the transfer unit, the method comprising:
determining an initial transfer current;
setting as a target voltage an output voltage of the power supply unit that is measured when the power supply unit supplies the determined initial transfer current to the transfer unit in a predetermined certain period before an image is transferred onto the transfer medium; and
transferring an image onto the transfer medium by applying the target voltage to the transfer unit by controlling transfer current that is supplied to the transfer unit based on a value of a feedback correction rate.
19. A method of controlling a transfer power of an image forming apparatus having a transfer unit that transfers an image onto a transfer medium and a power supply unit that provides a transfer power to the transfer unit, the method comprising:
applying transfer power to the transfer unit using a constant current method for a predetermined certain period before the image is transferred onto the transfer medium, whereby a target voltage is set; and
while the image is being transferred onto the transfer medium, applying a target voltage to the transfer unit using a constant voltage method by controlling transfer current that is supplied to the transfer unit based on a value of a feedback correction rate.
20. The method of claim 19, wherein the constant voltage method is performed by using a constant voltage power supplier or using a constant current power supplier which is controlled by firmware.