IMAGE FORMING APPARATUS AND DEVELOPER REMAINING AMOUNT DETECTING METHOD

Abstract

An image forming apparatus, which uses a developing device including: a developer carrying member developing an electrostatic latent image formed on an electrophotographic photosensitive member with a developer; a developer containing portion containing the developer; an agitating member provided rotatably in the developer containing portion to agitate the developer; and a developer remaining amount detecting member outputting a signal for detecting the remaining amount of the developer contained in the developer containing portion, the image forming apparatus including a main body controller to which the signal is input, and which detects the remaining amount of the developer, the main body controller detecting the remaining amount of the developer in the developer containing portion based on the amount of change per a unit revolution number of the agitating member in the band of fluctuation in the signal in association with the rotation of the agitating member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional configuration diagram illustrating one embodiment of an image forming apparatus according to the present invention.

FIGS. 2A and 2B are schematic cross sectional configuration diagrams of one embodiment of a developing device to which the present invention is applicable.

FIG. 3 is a block diagram illustrating one embodiment of a developer remaining amount detecting circuit.

FIG. 4A is a graph chart illustrating a relation between the remaining amount of toner and a capacitance value in a developer remaining amount detecting unit. FIG. 4B is a graph chart illustrating a relation between the radius of cross section of a developing sleeve and a difference A in capacitance.

FIGS. 5A and 5B are graph charts illustrating a relation between the remaining amount of toner and fluctuation in capacitance.

FIGS. 6A, 6B, 6C, and 6D are schematic cross sectional views illustrating toner and the movement of agitation in the developing device.

FIG. 7 is a chart illustrating a relation between the remaining amount of toner and the band of fluctuation.

FIG. 8A is a chart illustrating the remaining amount of toner and the band of fluctuation applied to the present invention. FIG. 8B is a chart illustrating a relation between the remaining amount of toner and the rate of change.

FIG. 9 is a flowchart showing toner remaining amount detecting operation in a first embodiment of the present invention.

FIGS. 10A and 10B are charts illustrating a toner LOW indicating point in the first embodiment of the present invention.

FIG. 11 is a block diagram of a main body controller.

FIG. 12 is a flowchart showing a toner remaining amount detecting operation in a second embodiment of the present invention.

FIG. 13 is a schematic cross sectional configuration diagram explaining another embodiment of an image forming apparatus according to the present invention.

FIG. 14 is a schematic cross sectional configuration diagram of one embodiment of a developing deice to which the present invention is applicable.

FIG. 15 is a schematic cross sectional configuration diagram of one embodiment of a process cartridge to which the present invention is applicable.

FIG. 16 is a block diagram illustrating another embodiment of a developer remaining amount detecting circuit.

FIG. 17 is a graph chart illustrating a relation between the remaining amount of toner and fluctuation in capacitance.

FIG. 18 is a block diagram of another embodiment of a main body controlling portion.

FIG. 19 is a graph chart illustrating a relation between the remaining amount of toner and fluctuation in detected values.

FIGS. 20A, 20B, 20C and 20D are schematic cross sectional views illustrating the movement of toner and agitation in the developing device.

FIG. 21 is a schematic cross sectional configuration diagram illustrating one example of a conventional image forming apparatus.

FIG. 22 is a schematic cross sectional configuration diagram of one example of a conventional developing device.

Claims

1. An image forming apparatus, which uses a developing device including: a developer carrying member developing an electrostatic latent image formed on an electrophotographic photosensitive member with a developer; a developer containing portion containing the developer; an agitating member provided rotatably in the developer containing portion to agitate the developer; and a developer remaining amount detecting member outputting a signal for detecting a remaining amount of the developer contained in the developer containing portion, the image forming apparatus comprising a main body controller to which the signal is input, and which detects the remaining amount of the developer, the main body controller detecting the remaining amount of the developer in the developer containing portion based on an amount of change per a unit revolution number of the agitating member in a band of fluctuation in the signal in association with a rotation of the agitating member.

2. An image forming apparatus according to claim 1, wherein the developer remaining amount detecting member is disposed in the developer containing portion, and disposed vertically above a center of rotation of the agitating member, and in a position more near to the developer carrying member than to the agitating member.

3. An image forming apparatus according to claim 1, wherein the developer remaining amount detecting member is an antenna member provided in the developer containing portion, the antenna member outputting a signal corresponding to a capacitance between the developer carrying member and the antenna member.

4. An image forming apparatus according to claim 3, wherein a distance between the developer carrying member and the antenna member is set so that the amount of change per the unit revolution number of the agitating member is substantially zero when the remaining amount of the developer in the developer containing portion reaches a predetermined amount.

5. An image forming apparatus according to claim 1, wherein the developer remaining amount detecting member includes a first antenna member to which a predetermined voltage is applied, and a second antenna member outputting a signal corresponding to a capacitance generated by a voltage applied to the first antenna member, the first and second antenna members being provided in the developer containing portion.

6. An image forming apparatus according to claim 5, wherein a distance between the first antenna member and the second antenna member is set so that the amount of change per the unit revolution number of the agitating member is substantially zero when the remaining amount of the developer in the developer containing portion reaches a predetermined amount.

7. A detecting method of detecting a remaining amount of a developer contained in a developer containing portion, in an image forming apparatus, which uses a developing device including: a developer carrying member developing an electrostatic latent image formed on an electrophotographic photosensitive member with a developer; the developer containing portion containing the developer; an agitating member provided rotatably in the developer containing portion to agitate the developer; and a developer remaining amount detecting member outputting a signal for detecting the remaining amount of the developer contained in the developer containing portion, the detecting method comprising detecting the remaining amount of the developer in the developer containing portion based on an amount of change per a unit revolution number of the agitating member in a band of fluctuation in the signal in association with a rotation of the agitating member.

8. A detecting method according to claim 7, wherein the developer remaining amount detecting member is disposed vertically above a center of rotation of the agitating member, and in a position more near to the developer carrying member than to the agitating member.

9. A detecting method according to claim 7, wherein the developer remaining amount detecting member outputs a signal corresponding to a capacitance between the developer carrying member and an antenna member provided in the developer containing portion.

10. A detecting method according to claim 9, wherein a distance between the developer carrying member and the antenna member is set so that the amount of change is substantially zero when the remaining amount of the developer in the developer containing portion reaches a predetermined amount.

11. A detecting method according to claim 7, wherein the developer remaining amount detecting member includes a first antenna member to which a predetermined voltage is applied, and a second antenna member outputting a signal corresponding to a capacitance generated by a voltage applied to the first antenna member, the first and second antenna members being provided in the developer containing portion.

12. A detecting method according to claim 11, wherein a distance between the first antenna member and the second antenna member is set so that the amount of change is substantially zero when the remaining amount of the developer in the developer containing portion reaches a predetermined amount.