Transfer power supply apparatus of an image forming machine
First Claim
1. A transfer power supply apparatus of an image forming machine applying a voltage in order to transfer an image created on an intermediate transfer medium onto a print medium conveyed between a transfer roller and a transfer backup roller, the transfer power supply apparatus comprising:
- a voltage computation unit computing a transfer voltage corresponding to resistance of the intermediate transfer medium;
an output voltage generator generating the transfer voltage according to the output from the voltage computation unit; and
a switching unit selectively applying the transfer voltage output from the output voltage generator,wherein the switching unit connects the transfer voltage output from the output voltage generator to the transfer roller when the image created on the intermediate transfer medium is transferred to the print medium, and connects the transfer voltage output from the output voltage generator to the transfer backup roller when the image is not transferred to the print medium.
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Accused Products
Abstract
A transfer power supply apparatus of an image forming machine which can maintain a predetermined degree of the quality of an image on a print medium even when the temperature of the surrounding environment varies. The image forming machine includes a voltage computation unit computing an appropriate voltage corresponding to resistance of an intermediate transfer medium, an output voltage generator generating a transfer voltage according to a signal output from the voltage computation unit, and a switching unit selectively applying a voltage output from the output voltage generator, wherein the switching unit connects a voltage output from the output voltage generator to a transfer roller when the image created on the intermediate transfer medium is transferred to a print medium, and connects a voltage output from the output voltage generator to a transfer backup roller when the image is not transferred to the print medium.
12 Citations
35 Claims
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1. A transfer power supply apparatus of an image forming machine applying a voltage in order to transfer an image created on an intermediate transfer medium onto a print medium conveyed between a transfer roller and a transfer backup roller, the transfer power supply apparatus comprising:
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a voltage computation unit computing a transfer voltage corresponding to resistance of the intermediate transfer medium; an output voltage generator generating the transfer voltage according to the output from the voltage computation unit; and a switching unit selectively applying the transfer voltage output from the output voltage generator, wherein the switching unit connects the transfer voltage output from the output voltage generator to the transfer roller when the image created on the intermediate transfer medium is transferred to the print medium, and connects the transfer voltage output from the output voltage generator to the transfer backup roller when the image is not transferred to the print medium. - View Dependent Claims (2, 3, 4, 5)
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6. A transfer power supply apparatus of an image forming machine applying a voltage in order to transfer an image created on an intermediate transfer medium onto a print medium conveyed between a transfer roller and a transfer backup roller, the transfer power supply apparatus comprising:
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a first transfer supply apparatus comprising, a first voltage computation unit computing a transfer voltage corresponding to resistance of the intermediate transfer medium, a first output voltage generator outputting the transfer voltage according to the output from the first voltage computation unit, and a first switch disposed between the first output voltage generator and the transfer roller; and a second transfer power supply apparatus comprising, a second voltage computation unit computing a transfer voltage corresponding to resistance of the intermediate transfer medium, a second output voltage generator outputting the transfer voltage according to a signal output from the second voltage computation unit, and a second switch disposed between the second output voltage generator and the transfer backup roller, wherein the second switch is turned off to prevent the second transfer power supply apparatus from applying the corresponding transfer voltage to the transfer backup roller when the first switch is turned on and the first transfer power supply apparatus supplies the corresponding transfer voltage to the transfer roller. - View Dependent Claims (7, 8)
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9. An image forming machine comprising:
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an intermediate transfer medium on which images developed by a plurality of developing units are overlapped thereby forming a predetermined color image; a transfer roller transferring the color image created on the intermediate transfer medium onto a print medium; a transfer backup roller supporting the transfer roller; and a transfer power supply apparatus comprising, a voltage computation unit computing a transfer voltage corresponding to the resistance of the intermediate transfer medium, an output voltage generator outputting the transfer voltage according to the output from the voltage computation unit, and a switching unit applying the transfer voltage output from the output voltage generator selectively to the transfer roller and the transfer backup roller; wherein the transfer power supply apparatus controls the switching unit to connect the transfer voltage output from the output voltage generator to the transfer roller when the color image created on the intermediate transfer medium is transferred to the print medium, and to connect the voltage output from the output voltage generator to the transfer backup roller when the color image is not transferred to the print medium. - View Dependent Claims (10, 11)
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12. An image forming machine comprising:
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an intermediate transfer medium on which images developed by a plurality of developing units are overlapped thereby forming a predetermined color image; a transfer roller transferring a color image created on the intermediate transfer medium onto a print medium; a transfer backup roller supporting the transfer roller; a first transfer power supply apparatus comprising; a first voltage computation unit computing a transfer voltage corresponding to resistance of the intermediate transfer medium, a first output voltage generator outputting the transfer voltage according to the output from the first voltage computation unit, and a first switch disposed between the first output voltage generator and the transfer roller; and a second transfer power supply apparatus comprising; a second voltage computation unit computing a transfer voltage corresponding to the resistance of the intermediate transfer medium, a second output voltage generator outputting the transfer voltage according to the output from the second voltage computation unit, and a second switch disposed between the second output voltage generator and the transfer backup roller; wherein the second switch is turned off to prevent the second transfer power supply apparatus from applying the corresponding transfer voltage to the transfer backup roller when the first switch is turned on and the first transfer power supply apparatus supplies the corresponding transfer voltage to the transfer roller. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of maintaining a constant transfer voltage from a power supply circuit to transfer an image from an intermediate transfer medium having a temperature-sensitive resistance value to a print medium, comprising:
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measuring a change in the resistance value of the intermediate transfer medium according to a change in a temperature of a surrounding environment; adjusting an output from the power supply circuit according to the change in the resistance value to thereby maintain the constant transfer voltage. - View Dependent Claims (27)
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28. A transfer power supply apparatus of an image forming machine applying a voltage in order to transfer an image created on an intermediate transfer medium onto a print medium conveyed between a transfer roller and a transfer backup roller, the transfer power supply apparatus comprising:
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a voltage computation unit computing a voltage level corresponding to a resistance of the intermediate transfer medium; and an output voltage generator generating a transfer voltage according to a signal output from the voltage computation unit. - View Dependent Claims (29)
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30. A printer comprising:
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an intermediate transfer medium on which an image is formed and having a varying resistance according to a change in temperature; a transfer roller facilitating a transfer of the image from the intermediate transfer medium onto a print medium using a voltage applied to the transfer roller; and a power supply unit providing the voltage to the transfer roller at a voltage level based on the resistance of the intermediate transfer medium.
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31. A method of printing with an apparatus that comprises an intermediate transfer medium on which images developed by a plurality of developing units are overlapped thereby forming a predetermined color image, a transfer roller transferring a color image created on the intermediate transfer medium onto a print medium, and a transfer backup roller supporting the transfer roller, the method comprising:
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applying a voltage to the transfer roller; measuring a current in the intermediate transfer medium while the voltage is applied; computing a resistance value of the intermediate transfer medium based on the measured current; adjusting the applied voltage according to the computed resistance value; and conveying a development agent of a created image from the intermediate transfer medium to a print medium as a result of an electrostatic field from the applied voltage. - View Dependent Claims (32, 33, 34, 35)
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Specification