Image forming apparatus having constant current and voltage control in the charging and transfer regions
First Claim
1. An image forming apparatus, comprising:
- a movable image bearing member;
image forming means for forming an image on said image bearing member;
a charging member disposed opposing said image bearing member; and
bias applying means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member by supplying a constant voltage level thereto when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control by supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.
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Abstract
An image forming apparatus includes a movable image bearing member; an image forming device for forming an image on the image bearing member; a charging member disposed opposed to the image bearing member; and bias application device for applying a bias voltage to the charging member, wherein the bias applying device effects a constant voltage control to the charging member when an image area of the image bearing member is in a charging region of the charging member, and effects a constant current control during at least a part of a period in which an area of the image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control.
66 Citations
93 Claims
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1. An image forming apparatus, comprising:
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a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposing said image bearing member; and bias applying means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member by supplying a constant voltage level thereto when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control by supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region, and wherein a level of a constant voltage of the constant voltage control is determined during the constant current control. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 71)
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24. An image forming apparatus, comprising:
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a movable image bearing member; image forming means for forming an image on said image bearing member; transfer means for transferring the image from said image bearing member onto a transfer material in an image transfer region, said transfer means including a charging member opposing said image bearing member and bias applying means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member by supplying a constant voltage level thereto when an image area of said image bearing member is in the transfer region, and effects a constant current control to said charging member by supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during at least a part of a period in which an area of said image bearing member other than the image area is in the transfer region, wherein a level of a voltage of the constant voltage control is determined on the basis of a voltage produced in the transfer means during the constant current control. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 72)
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47. An image forming apparatus comprising:
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a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member opposed to said image bearing member; bias applying means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member by supplying a constant voltage level thereto when an image area of said image bearing member is in a charging region of said charging member, and effect a constant current control to said charging member by supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during a part of period in which an area of said image bearing member other than the image area is in the charging region; and storing means for storing a voltage appearing during the constant current control, and determining a level of voltage of the constant voltage control on the basis of the stored voltage. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 73)
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70. An image forming apparatus comprising:
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a movable image bearing member; image forming means for forming an image on said image bearing member; a charging member disposed opposing said image bearing member; and bias applying means for applying a bias voltage to said charging member, wherein said bias applying means effects a constant voltage control to said charging member by supplying a constant voltage level to said charging member when an image area of said image bearing member is in a charging region of said charging member, and effects a constant current control by supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during at least a part of a period in which an area of said image bearing member other than the image area is in the charging region.
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74. An image forming apparatus comprising:
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image forming means for forming an image on a recording material, said image forming means including a movable image bearing member, a charging member disposed opposing said image bearing member and a power source for supplying electric power to said charging member; first control means for supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, during at least a part of a period in which an area of said image bearing member other than an image area is in a charging region of said charging member, while said image bearing member moves; storing means for storing a voltage provided during operation of said first control means; and second control means for controlling an image forming condition of said image forming means on the basis of the voltage stored by said storing means. - View Dependent Claims (75, 76, 77, 78, 79, 80, 81, 82, 83, 93)
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84. An image forming apparatus, comprising:
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image forming means for forming an image on a recording material, said image forming means including a movable image bearing member, a charging member disposed opposing said image bearing member and a power source for supplying electric power to said charging member; first control means for supplying a current to said charging member so as to maintain a constant level of current flow from said charging member to said image bearing member, while said image bearing member moves, during at least a part of a period in which the recording material is not in a charging region of said charging member; storing means for storing a voltage provided during operation of said first control means; and second control means for controlling an image forming condition of said image forming means on the basis of the voltage stored by said storing means. - View Dependent Claims (85, 86, 87, 88, 89, 90, 91)
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92. An apparatus according to any one of claims to 82 and 84 to 90, wherein the voltage stored by said storing means is a voltage applied to said charging means during operation of said first control means.
Specification