Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsKota Mori, Takeshi Fujino
Life of this patent
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Abstract
An image forming apparatus includes a photosensitive member, a charging roller, a voltage source, a current detecting member, and a setting portion configured to set the DC voltage applied to the charging roller in an image forming period on the basis of a detection result of the detecting member when a DC voltage less than a discharge start voltage is applied from the voltage source to the charging roller in a period other than the image forming period, wherein the setting portion sets the DC voltage so that an absolute value of the DC voltage when an absolute value of the detected current is a first value is larger than an absolute value of the DC voltage when the absolute value of the detected current is a second value smaller than the first value.
Claims10
An image forming apparatus comprising:
- a photosensitive member on which an electrostatic latent image is formed;
- a charging roller configured to electrically charge said photosensitive member in contact with said photosensitive member;
- a voltage source configured to apply only a DC voltage to said charging roller;
- a detecting member configured to detect a current flowing from said charging member into said photosensitive member;
- and
- a setting portion configured to set the DC voltage applied to said charging roller in an image forming period on the basis of a detection result of said detecting member when the DC voltage less than a discharge start voltage is applied from said voltage source to said charging roller in a period other than the image forming period, wherein said setting portion sets the DC voltage so that an absolute value of the DC voltage when an absolute value of the detected current is a first value is larger than an absolute value of the DC voltage when the absolute value of the detected current is a second value smaller than the first value.
An image forming apparatus comprising:
- a photosensitive member on which an electrostatic latent image is formed;
- a charging roller configured to electrically charge said photosensitive member in contact with said photosensitive member;
- a voltage source configured to apply only a DC voltage to said charging roller;
- a detecting member configured to detect a current flowing from said charging member into said photosensitive member;
- a discharging exposure member configured to expose a surface of said photosensitive member after a toner image is formed and before the electrostatic latent image is formed;
- and
- a setting portion configured to set a discharging exposure amount of said discharging exposure member in an image forming period on the basis of a detection result of said detecting member when the DC voltage less than a discharge start voltage is applied from said voltage source to said charging roller in a period other than the image forming period, wherein said setting portion sets the discharging exposure amount so that the discharging exposure amount when an absolute value of the detected current is a first value is larger than the discharging exposure amount when the absolute value of the detected current is a second value smaller than the first value.
An image forming apparatus comprising:
- a photosensitive member on which an electrostatic latent image is formed;
- a charging roller configured to electrically charge said photosensitive member in contact with said photosensitive member;
- a voltage source configured to apply only a DC voltage to said charging roller;
- a detecting member configured to detect a current flowing from said charging member into said photosensitive member;
- a driving member configured to drive said photosensitive member at predetermined rotational speed;
- and
- a setting portion configured to set the rotational speed of said photosensitive member by said driving member in an image forming period on the basis of a detection result of said detecting member when the DC voltage less than a discharge start voltage is applied from said voltage source to said charging roller in a period other than the image forming period, wherein said setting portion sets the rotational speed so that the rotational speed when an absolute value of the detected current is a first value is higher than the rotational speed when the absolute value of the detected current is a second value smaller than the first value.
Dependencies are inferred from the claim text.