Image Forming Apparatus and Charge-Voltage Generating Method
AssigneeBrother Kogyo Kabushiki Kaisha
InventorHiroyuki NAGANAWA
Life of this patent
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Abstract
An image forming apparatus includes: a calculating device configured to, in a testing mode to replace a discharge path between a charging wire and a grid of a charger with a testing resistor having a predetermined resistance, calculate a charge voltage using the resistance of the testing resistor and a detection value by a grid-current detecting circuit; and a controller configured to, in an image forming mode to actually form an image, detect the charge voltage from a feedback voltage using a relation between a value of the feedback voltage which is detected by a charge-voltage detecting circuit in the testing mode and the charge voltage calculated by the calculating device.
Claims9
An image forming apparatus comprising:
- a charger including a charging wire and a grid;
- a voltage output circuit including a transformer having an auxiliary winding, the voltage output circuit being configured to generate a charge voltage using the transformer and apply the charge voltage to the charger;
- a grid-current detecting circuit configured to detect a grid current that flows between the charging wire and the grid in accordance with the applying of the charge voltage;
- a charge-voltage detecting circuit configured to obtain the charge voltage from a feedback voltage that is generated by the auxiliary winding;
- a calculating device configured to, in a testing mode to replace a discharge path between the charging wire and the grid with a testing resistor having a predetermined resistance, calculate the charge voltage using the resistance of the testing resistor and a detection value by the grid-current detecting circuit;
- and
- a controller configured to, in an image forming mode to form an image, detect the charge voltage from the feedback voltage using a relation between a value of the feedback voltage which is detected by the charge-voltage detecting circuit in the testing mode and the charge voltage calculated by the calculating device.
A method of generating charge voltage when applying a charge voltage to a charger including a charging wire and a grid by a charge-voltage applying circuit including a transformer having an auxiliary winding configured to generate a feedback voltage in accordance with the charge voltage, the method comprising the steps of:
- prior to generating the charge voltage, replacing a discharge path between the charging wire and the grid of the charger with a testing tool having a predetermined electrical parameter and applying a testing charge voltage to the charger;
- detecting a grid current that flows between the charging wire and the grid in accordance with the applying of the testing charge voltage;
- detecting the feedback voltage in accordance with the applying of the testing charge voltage;
- calculating the testing charge voltage using the electrical parameter of the testing tool and the detected grid current;
- calculating an approximate equation using the detected feedback voltage and the calculated testing charge voltage, the approximate equation representing a relation between the feedback voltage and the charge voltage;
- detecting the charge voltage from the feedback voltage by using the approximate equation, when removing the testing tool and generating the charge voltage;
- and
- controlling the charge-voltage applying circuit so as to output the detected charge voltage.
Dependencies are inferred from the claim text.