Image forming apparatus and charging device therefor
First Claim
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1. A charging device comprising:
- a charge roller adjoining or contacting a surface of a photoconductive element;
a DC voltage source configured to output a DC voltage;
an AC voltage source configured to output an AC voltage;
voltage applying means for superposing the DC voltage and the AC voltage and applying a resulting superposed voltage to said charge roller; and
waveform control means for causing said AC voltage source to generate the AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range.
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Abstract
A charging device of the present invention includes a charge roller adjoining or contacting the surface of a photoconductive element. A DC and an AC voltage source output a DC and an AC voltage, respectively. A voltage applying device superposes the DC and AC voltage and applies the resulting superposed voltage to the charge roller. A waveform controller causes the AC voltage source to generate an AC voltage having the waveform pattern of particular noise and frequency lying in a preselected range.
11 Citations
21 Claims
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1. A charging device comprising:
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a charge roller adjoining or contacting a surface of a photoconductive element;
a DC voltage source configured to output a DC voltage;
an AC voltage source configured to output an AC voltage;
voltage applying means for superposing the DC voltage and the AC voltage and applying a resulting superposed voltage to said charge roller; and
waveform control means for causing said AC voltage source to generate the AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A process cartridge comprising:
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a photoconductive element;
a cartridge case by which said photoconductive element is rotatably supported;
a charging device disposed in said cartridge case and configured to establish a potential difference between said charging device and said photoconductive element for thereby uniformly charging a surface of said photoconductive drum; and
a developing device disposed in said cartridge case and configured to feed toner to the surface of said photoconductive element;
said charging device comprising;
a charge roller adjoining or contacting the surface of said photoconductive element;
a DC voltage source configured to output a DC voltage;
an AC voltage source configured to output an AC voltage;
voltage applying means for superposing the DC voltage and the AC voltage and applying a resulting superposed voltage to said charge roller; and
waveform control means for causing said AC voltage source to generate the AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range.
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18. An image forming apparatus comprising:
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a process cartridge comprising a photoconductive element, a cartridge case by which said photoconductive element is rotatably supported, a charging device disposed in said cartridge case and configured to establish a potential difference between said charging device and said photoconductive element for thereby uniformly charging a surface of said photoconductive drum, and a developing device disposed in said cartridge case and configured to feed toner to said surface of said photoconductive element;
an optical scanning unit configured to optically scan the surface of said photoconductive element charged by said charging device; and
an image transferring device configured to transfer the toner from the surface of said photoconductive element to a recording medium;
said charging device comprising;
a charge roller adjoining or contacting the surface of said photoconductive element;
a DC voltage source configured to output a DC voltage;
an AC voltage source configured to output an AC voltage;
voltage applying means for superposing the DC voltage and the AC voltage and applying a resulting superposed voltage to said charge roller; and
waveform control means for causing said AC voltage source to generate the AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range.
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19. An image forming apparatus comprising:
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a photoconductive element;
a charging device configured to establish a potential difference between said charging device and said photoconductive element for thereby uniformly charging a surface of said photoconductive element, said charging device comprising a charge roller adjoining or contacting a surface of said photoconductive element, a DC voltage source configured to output a DC voltage, an AC voltage source configured to output an AC voltage, voltage applying means for superposing said DC voltage and said AC voltage and applying a resulting superposed voltage to said charge roller, and waveform control means for causing said AC voltage source to generate said AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range;
an optical scanning device configured to optically scan the surface of said photoconductive element charged by said charging device;
a developing device configured to transfer toner to the surface of said photoconductive element scanned by said optical scanning device; and
an image transferring device configured to transfer the toner from the surface of said photoconductive element to a recording medium;
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20. A copier comprising:
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an image reading device configured to read a document image; and
an image forming apparatus configured to form an image on a recording medium in accordance with image data output from said image reading device;
said image forming apparatus comprising;
a process cartridge comprising a photoconductive element, a cartridge case by which said photoconductive element is rotatably supported, a charging device disposed in said cartridge case and configured to establish a potential difference between said charging device and said photoconductive element for thereby uniformly charging a surface of said photoconductive drum, and a developing device disposed in said cartridge case and configured to feed toner to said surface of said photoconductive element;
an optical scanning unit configured to optically scan the surface of said photoconductive element charged by said charging device; and
an image transferring device configured to transfer the toner from the surface of said photoconductive element to a recording medium;
said charging device comprising;
a charge roller adjoining or contacting the surface of said photoconductive element;
a DC voltage source configured to output a DC voltage;
an AC voltage source configured to output an AC voltage;
voltage applying means for superposing the DC voltage and the AC voltage and applying a resulting superposed voltage to said charge roller; and
waveform control means for causing said AC voltage source to generate the AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range.
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21. A copier comprising:
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an image reading device configured to read a document image; and
an image forming apparatus configured to form an image on a recording medium in accordance with image data output from said image reading device;
a photoconductive element;
a charging device configured to establish a potential difference between said charging device and said photoconductive element for thereby uniformly charging a surface of said photoconductive element, said charging device comprising a charge roller adjoining or contacting a surface of said photoconductive element, a DC voltage source configured to output a DC voltage, an AC voltage source configured to output an AC voltage, voltage applying means for superposing said DC voltage and said AC voltage and applying a resulting superposed voltage to said charge roller, and waveform control means for causing said AC voltage source to generate said AC voltage having a waveform pattern of particular noise and a frequency lying in a preselected range;
an optical scanning device configured to optically scan the surface of said photoconductive element charged by said charging device;
a developing device configured to transfer toner to the surface of said photoconductive element scanned by said optical scanning device; and
an image transferring device configured to transfer the toner from the surface of said photoconductive element to a recording medium.
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Specification