JP2010175791A - Determination unit, developer replenishment unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the quantity of a developer from being erroneously detected with respect to a determination unit for determining the quantity of the developer, in a developing unit, a developer replenishment unit provided with the determination unit, and furthermore an image forming apparatus. <P>SOLUTION: The excess or deficiency of toner is determined based on both of a determination by a piezo-electric oscillating method and a determination based on motor current. That is, the detection error is prevented by: determining the toner shortage when the toner shortage is determined by either one of determination result by the piezo-electric oscillating method and the determination result based on the motor current; and determining the toner excess when the toner excess is determined by both of them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a determination device that determines a developer amount in a developing device, a developer supply device including the determination device, and an image forming apparatus.

  Conventionally, as a mechanism for detecting the developer amount in the developing device, a technique for detecting the remaining amount from the starting current value of the toner stirring motor has been proposed (Patent Document 1).

JP 2002-148886 A

  However, since the starting current of the agitation motor varies depending on the humidity and the charging polarity of the toner, the conventional technology has a problem that erroneous detection is likely to occur.

  Then, an object of this invention is to provide the technique which can prevent a misdetection effectively.

  In order to solve the above-described problem, a determination apparatus according to claim 1 includes: a developer container; a stirring unit that stirs the developer in the developer container; and a developer in the developer container. A developing unit for developing, and a determination device for determining the amount of developer in the developer container in a developing device, wherein the magnitude of resistance applied to the stirring unit exceeds an upper limit when the stirring unit is in operation Detection results of the first detection unit, the second detection unit detecting the developer at the upper limit position in the developer container, and the detection results of the first and second detection units are the magnitude of the resistance. Exceeds the upper limit value, and indicates that the developer is present at the upper limit position, an excess determination unit that determines that the developer is excessive.

  According to a second aspect of the present invention, in the determination device according to the first aspect, the third detection unit that detects that the magnitude of the resistance is lower than a lower limit value, and a lower limit position in the developer container. When the detection results of the fourth detection unit that detects the developer and the third and fourth detection units indicate that the magnitude of the resistance falls below the lower limit value or that there is no developer at the lower limit position. And a deficiency determination unit that determines that the developer is deficient.

  In order to solve the above problems, the half ground apparatus according to claim 3 includes a developer container, a stirring unit for stirring the developer in the developer container, and the developer in the developer container. A developing unit that develops an image by a determination device that determines the amount of developer in the developer container in a developing device, wherein a current value for operating the stirring unit exceeds an upper limit value. Detection result of an upper limit side current detection unit to detect, a piezoelectric vibration type upper limit side developer sensor for detecting developer at the upper limit position in the developer container, and a detection result of the upper limit side current detection unit and the upper limit side developer sensor However, when the current value exceeds the upper limit value and the developer is present at the upper limit position, an excess determination unit that determines that the developer is excessive is provided.

  According to a fourth aspect of the present invention, the determination device according to the third aspect includes a lower limit side current detection unit that detects that the current value has fallen below a lower limit value, and development at a lower limit position in the developer container. Piezoelectric vibration type lower limit developer sensor for detecting the agent, and the detection results of the lower limit side current detector and the lower limit developer sensor indicate that the current value is lower than the lower limit value, or the developer is at the lower limit position. If it indicates that there is no toner, a shortage determination unit that determines that the developer is short may be further provided.

  In addition, as described in claims 5 and 6, the determination device described above can be applied to a developer supply device. That is, the developer replenishing device includes, for example, a developer replenishing unit that replenishes the developer to a developing device including a developer containing container and a stirring unit that stirs the developer in the developer containing container; 4. The determination device according to claim 1 or 3, wherein the amount of developer in the developer container is determined; and replenishment for stopping developer replenishment by the developer replenishment unit when the excess determination unit determines that the developer is excessive And a stop control unit.

  The developer replenishing device includes, for example, a developer replenishing unit that replenishes the developer to a developing device including a developer containing container and a stirring unit that stirs the developer in the developer containing container; The determination device according to claim 2 or 4, wherein the amount of developer in the developer container is determined; and replenishment for starting developer replenishment by the developer replenishment unit when the deficiency determination unit determines that the developer is deficient A start control unit; and a replenishment stop control unit that stops developer replenishment by the developer replenishment unit when the excess determination unit determines that the developer is excessive.

  According to a seventh aspect of the present invention, the developer supply device described above can be applied to an image forming apparatus. That is, the image forming apparatus includes a developer container, a stirring unit that stirs the developer in the developer container, and a developing unit that develops an image with the developer in the developer container. And a developer replenishing device according to claim 5 or 6.

  In the determination apparatus according to the present invention, it is determined that the developer is excessive when the developer reaches the upper limit from both the resistance in stirring of the developer and the position of the developer. Therefore, erroneous detection is effectively prevented.

FIG. 2 is a cross-sectional view showing the main configuration of the multifunction machine 1 according to the embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a main configuration of a developing device 24 in the multifunction machine 1. FIG. 3 is a block diagram illustrating an outline of a toner amount detection mechanism and a toner supply control mechanism in the multifunction machine. FIG. 4 is a timing chart showing output signals of respective units in FIG. 3 when the toner amount is appropriate. FIG. 4 is a timing chart showing output signals of respective units in FIG. 3 when toner is insufficient. FIG. 4 is a timing chart showing output signals of respective parts in FIG. 3 when toner is excessive. A table showing final toner amount determination results and toner supply control contents.

[1] First Embodiment Hereinafter, a multifunction machine 1 according to an embodiment of the present invention will be described. In the following description, “upper” and “lower” refer to directions in the normal installation posture of the multifunction machine 1. Further, the drawings are schematic diagrams, and details of each part are omitted.

(1-1) Multifunction machine 1
With reference to FIG. 1, an outline of the configuration of the multifunction machine 1 will be described. FIG. 1 is a cross-sectional view showing an internal configuration of the multifunction machine 1.

  The multifunction device 1 is an example of an image forming apparatus. As illustrated in FIG. 1, as illustrated in FIG. 1, the image forming unit 2, the fixing unit 3, the paper storage unit 4, the paper transport unit 5, the paper discharge tray 6, the toner supply unit 7, A scanner 8 and the like are provided. The multifunction device 1 further includes a communication unit that is connected to an external device such as a computer (not shown) and receives image data sent from the external device, a control device that controls each unit in the multifunction device 1, and the like.

  The image forming unit 2 includes a photosensitive drum 21, a charging device 22, a drawing device 23, a developing device 24, a transfer device 25, a cleaning device 26, and a charge eliminating device 27.

  The photosensitive drum 21 is a cylindrical member that can carry an electrostatic latent image on the surface. The photosensitive drum 21 is rotatably provided around a rotation axis extending in the height direction of the cylinder (a direction perpendicular to the paper surface of FIG. 1). The direction of rotation is indicated by an arrow in FIG.

  The charging device 22, the drawing device 23, the developing device 24, the transfer device 25, the cleaning device 26, and the charge eliminating device 27 are arranged around the photosensitive drum 21 in this order along the rotation direction of the photosensitive drum 21. .

  The charging device 22 uniformly charges the surface of the photosensitive drum 21. In this embodiment, since the charging polarity of the toner is positive, the charging polarity by the charging device 22 is negative.

  The drawing device 23 includes a laser light source and a mirror, and draws an electrostatic latent image by irradiating light on the surface of the charged photosensitive drum 21 along the image data. The image data used may be data obtained by the scanner 8 or data transmitted from an external device.

  The developing device 24 develops the electrostatic latent image by supplying toner to the photosensitive drum 21. The developed image is called a toner image. Details of the developing device 24 will be described later with reference to FIG.

  The transfer device 25 includes a transfer roller 25 a disposed so as to face the photosensitive drum 21, a voltage application unit (not shown) that applies a voltage having a polarity (negative polarity) opposite to that of toner to the roller, and the like. The toner image is transferred onto the paper P.

  The cleaning device 26 removes toner remaining on the photosensitive drum 21 after transfer.

  The neutralization device 27 eliminates the electrostatic latent image by neutralizing the surface of the photosensitive drum 21 after the toner is removed.

  The fixing unit 3 includes a heat roller and a pressure roller facing the heat roller, and fixes the toner image on the transferred paper P by heat pressure bonding.

  The paper storage unit 4 stores paper P.

  The paper transport unit 5 transports the paper P from the paper storage unit 4 to the paper discharge tray 6 through the transfer unit 25 and the fixing unit 3 in order. Specifically, the paper transport unit 5 feeds the paper P drawn between the transfer roller 25a and the photosensitive drum 21 with the drawing roller that pulls out the paper from the paper storage unit 4, and the fixing unit. 3, a transport roller group that transports the paper P to the paper discharge tray 6, a guide member that guides the paper P between the rollers, and a drive unit that rotates each roller.

  The toner supply unit 7 supplies toner to the developing device 24. Specifically, the toner replenishing unit 7 includes a toner tank 71 for storing toner, and although not shown, a toner conveyance path from the toner tank 71 to the developing device 24 and a toner conveyance path from the toner tank by rotating. And a conveying screw for conveying the toner to the developing device 24. Further, the toner replenishing unit 7 includes a toner replenishing motor 72 (FIG. 3) that rotates the conveying screw.

  The scanner 8 reads a document on a platen glass (not shown) and an image on a document transported by an automatic document transport device to obtain image data. Specifically, the scanner 8 includes a reading unit such as a CCD, a light source, and optical members such as a mirror and a lens that guide light from the light source to the document and guide reflected light from the document to the reading unit. .

(1-2) Developing Device FIG. 2 is a sectional view of the developing device 24. The developing device 24 includes a container 241, a first spiral 242, a second spiral 243, and a developing roller 244.

  The container 241 is an example of a developer storage container, and stores toner therein.

  Inside the container 241, a partition member 241c formed by extending the bottom surface of the container 241 upward is provided. The interior of the container 241 is partitioned into a stirring chamber 241a and a developing chamber 241b by the partition portion 241c. Since there is a gap between the partition member 241c and the upper surface of the container 241, the stirring chamber 241a and the developing chamber 241b are connected by this gap.

  The stirring chamber 241a is provided with a supply port 241d. Toner is supplied from the toner replenishing device 7 to the container 241 through the replenishing port 241d. A first stirring member 242 is provided in the stirring chamber 241a. The first stirring member 242 includes a shaft 242a extending in a direction perpendicular to the paper surface of FIG. 2 and a spiral blade member 242b provided on the peripheral surface of the shaft 242a. The shaft 242a is rotatably provided, and the entire first stirring member 242 is rotated in the direction of the arrow by the operation of a stirring motor 246 (FIG. 3) described later. The rotation of the first agitating member 242 causes the toner to be agitated and moves in the longitudinal direction of the container 241 (direction perpendicular to the paper surface of FIG. 2), and passes through the gap between the partition member 241c and the upper surface of the container 241. To move to the developing chamber 241b.

  A second stirring member 243 is provided in the developing chamber 241b. The second stirring member 243 includes a shaft 243a parallel to the shaft 242a and a spiral blade member 243b provided on the peripheral surface of the shaft 243a. The shaft 243a is also rotatable like the shaft 242a, and the entire second stirring member 242 is rotated in the arrow direction by the operation of the stirring motor 246 (FIG. 3). The toner in the developing chamber 241 b is stirred by the rotating second stirring member 242.

  An opening 241e is provided in a portion of the developing chamber 241b that faces the photosensitive drum 21. The developing roller 244 is rotatably arranged so as to be exposed from the opening 241e in the container 241. The toner in the developing chamber 241 b adheres to the developing roller 244 and is held at a position facing the photosensitive drum 21. When the developing roller 244 is rotated by a developing driving unit (not shown), toner adheres to the electrostatic latent image on the photosensitive drum 21 and the electrostatic latent image is developed. That is, the developing roller 244 functions as a developing unit.

  The stirring motor 246 is controlled to rotate by a control device (not shown) during development and toner replenishment.

(1-3) Toner sensors 281 and 282
As shown in FIG. 2, a lower limit side toner sensor 281 and an upper limit side toner sensor 282 disposed above the lower limit side toner sensor 281 are provided on the side surface of the stirring chamber 241a. Both the lower limit side toner sensor 281 and the upper limit side toner sensor 282 are piezoelectric vibration type sensors each including a piezoelectric element.

  The detection surfaces 281a and 282a of the toner sensors 281 and 282 are arranged so as to slightly protrude inside the stirring chamber 241a from the inner wall of the stirring chamber 241a. A voltage is applied to each of the toner sensors 281 and 282 at a predetermined cycle from a voltage application circuit (not shown). Then, in this cycle, the detection surfaces of the toner sensors 281 and 282 vibrate in a direction intersecting with the inner wall of the stirring chamber 241a. Each of the toner sensors 281 and 282 has a detection circuit. When the piezoelectric element vibrates, positive and negative voltages are input to the detection circuit, and when the vibration stops, a positive voltage is input to the detection circuit. It is configured as follows. The detection circuit outputs a signal indicating that toner is present when a positive voltage is input for a predetermined time or more.

  That is, if the height of the toner in the stirring chamber 241a is less than the height of the position where the detection surface 281a of the lower limit toner sensor 281 is disposed, the piezoelectric element of the lower limit toner sensor 281 vibrates and the height of the toner is detected. If the arrangement position of the surface 281 is reached, the vibration of the piezoelectric element stops. Therefore, it is possible to determine whether the toner is at the lower limit position by referring to the output signal of the detection circuit. The same applies to the upper limit toner sensor 282.

(1-4) Toner Amount Detection and Toner Supply FIG. 3 is a block diagram showing an outline of a toner amount detection mechanism and a toner supply control mechanism in the multifunction machine 1.

  As shown in FIG. 3, the multifunction device 1 has a sub-determination unit 901, a current sensor 910, a lower limit side comparator 921, an upper limit side comparator 922, a shortage detection unit 931, and an excess detection unit 932, in addition to the configuration described above. A main determination unit 940 and a toner supply control unit 941.

  Output signals from the lower limit side toner sensor 281 and the upper limit side toner sensor 282 are input to the sub determination unit 901. The sub determination unit 901 determines that the toner is insufficient if the output signal of the lower limit side toner sensor 281 indicates that the toner is insufficient. The sub-determination unit 901 determines that the toner amount is appropriate if the output signal of the lower limit side toner sensor 281 indicates that the toner is present and the output signal of the upper limit side toner sensor 282 indicates that the toner is insufficient. The sub determination unit 901 further determines that the toner is excessive if the output signal of the upper limit side toner sensor 282 indicates that there is toner.

  The current sensor 910 detects a current (motor current) supplied from the motor drive unit 247 to the agitation motor 246 as an example of a mechanism for detecting resistance applied to the agitation of the toner in the container 241. That is, the current sensor 910 detects a current required for operating the stirring motor 246.

  The lower limit side comparator 921, the upper limit side comparator 922, the shortage detection unit 931, and the excess detection unit 932 will be described with reference to FIGS. FIG. 4 is a timing chart showing the output signals of the respective parts when the toner amount is appropriate, FIG. 5 when the toner is insufficient, and FIG. 6 when the toner is excessive.

  As shown in FIG. 4, when the toner amount is appropriate, an inrush current is generated at the start of rotation of the motor, but the motor current value in the subsequent steady state is not less than the lower limit value L1 and not more than the upper limit value L2. The upper limit comparator 922 compares the upper limit value L2 with the motor current value, and outputs an upper limit comparison signal “1” when the motor current value exceeds the upper limit value L2. However, since the motor current value exceeds the upper limit value L2, that is, the output period of the upper limit side comparison signal “1” is shorter than the predetermined period T2, the excess detection signal of the excess detection unit 932 remains “0”.

  As shown in FIG. 5, the lower limit side comparator 921 compares the lower limit value L1 with the motor current value, and outputs a lower limit side comparison signal “1” when the motor current value falls below the lower limit L1. When the period during which the lower limit side comparison signal is “1” is equal to or greater than the predetermined period T1, the shortage detection unit 931 outputs a shortage detection signal “1” as a signal indicating a shortage of toner.

  As shown in FIG. 6, when the period during which the upper limit comparison signal of the upper limit comparator 922 is “1” is equal to or longer than the predetermined period T2, the excess detection unit 932 outputs the excess detection signal “1”.

  Next, the determination in the main determination unit 940 will be described with reference to FIG. FIG. 7 is a table showing the final toner amount determination result and the toner supply control content.

  As shown in the first to third stages of the “toner amount final determination” column in FIG. 7, the main determination unit 940 includes the determination result of the sub determination unit 901 (determination result by the piezoelectric vibration method) and the shortage detection unit. If at least one of the detection results 931 (the determination result based on the motor current) indicates “toner shortage”, it is determined that the toner is insufficient. In response to this result, the toner replenishment control unit 941 starts toner replenishment.

  On the other hand, as shown in the bottom of FIG. 7, the main determination unit 940 is excessive in toner when both the determination result of the sub determination unit 901 and the detection result of the excessive detection unit 932 indicate “too much toner”. Is determined. That is, when either one of the results indicates “toner appropriate”, it is not determined that the toner is excessive. When the main determination unit 940 determines that the toner is excessive, the toner supply control unit 941 stops the toner supply.

  As described above, since the toner amount is determined by combining the detection result based on the piezoelectric vibration method and the detection result based on the motor current, the multifunction device 1 is unlikely to erroneously determine the toner amount.

  3, for example, the sub determination unit 901, the main determination unit 940, the toner replenishment control unit 941, and the like, a CPU (Central Processing Unit) executes a program in a storage medium such as a ROM (Read Only Memory). This is possible by doing.

[2] Other Embodiments (2-1) In the first embodiment, one stirring motor 246 and two stirring members 242 and 243 function as a stirring unit. However, the present invention is not limited to this. For example, one stirring motor may be provided for one stirring member, and one stirring member may be provided. Further, the stirring member is not limited to the spiral shape as in the first embodiment.

  (2-2) The current sensor 910, the upper limit comparator 922, and the excess detection unit 932 according to the first embodiment detect that the resistance applied to the agitation unit exceeds the upper limit during toner agitation. It is possible to replace this mechanism. Similarly, the current sensor 910, the lower limit comparator 921, and the shortage detection unit 931 can be replaced with other mechanisms that detect that the magnitude of this resistance is lower than the lower limit.

(2-3) The upper limit toner sensor 282, the lower limit toner sensor 281 and the sub determination unit 901 in the first embodiment can be replaced with other mechanisms for detecting the position of the toner.
Further, as the upper limit side toner sensor 282 and the lower limit side toner sensor 281, in addition to the piezoelectric vibration type sensor, other sensors such as a magnetic permeability detection method and an optical type can be adopted.

  (2-4) In the first embodiment, the toner supply unit 7, the toner supply control unit 941, and the like function as a developer supply device. That is, the developer replenishing device is incorporated in the multifunction peripheral (image forming apparatus), but the developer replenishing device may be separate from the image forming apparatus. Similarly, the determination device can be configured separately from the developer supply device and the image forming apparatus.

(2-5) In the first embodiment, a second detector (upper limit developer sensor) that detects the developer at the upper limit position and a fourth detector (lower limit developer sensor) that detects the developer at the lower limit position ) Are separately provided as the upper limit side toner sensor 282 and the lower limit side toner sensor 281, respectively. However, both functions of these detection units can be realized by a single sensor. That is, it is possible to use both upper limit detection and lower limit detection with a single piezoelectric vibration type sensor. (2-6) In the first embodiment, the current sensor 910, the upper limit comparator 922, and the excess detection unit 932 include the upper limit detection. Functions as a side current detector. That is, as an example of a first detection unit that detects that the magnitude of the resistance applied to the stirring unit exceeds the upper limit value when the stirring unit is in operation, excessive toner detection based on the current value of the stirring motor 246 is performed. To do.

  In the first embodiment, the current sensor 910, the lower limit side comparator 921, and the shortage detection unit 931 function as a lower limit side current hand detection unit. That is, as an example of a third detection unit that detects that the magnitude of the resistance applied to the stirring unit has fallen below the lower limit when these members are operating, the toner shortage detection based on the current value of the stirring motor 246 is detected. To do.

  However, the configuration of the first and second detection units is not limited to this, and can be changed as appropriate.

  (2-7) In the first embodiment, the sub determination unit 901 and the main determination unit 940 cooperate to function as an example of an excess determination unit and an insufficient determination unit. Specifically, the final determination of excessive / insufficient toner based on the determination results output from the detection results of the toner sensors 281 and 282 and the detection results of the excess detection unit 932 and the lack detection unit 931. Is performed by the main determination unit 940. That is, a plurality of members surrounded by a dotted line denoted by reference numeral “950” in FIG. 3 cooperate to function as a determination device.

  However, the present invention is not limited to this, and can be appropriately changed within the scope described in the claims.

  (2-8) The technique obtained by appropriately combining different embodiments is also included in the embodiment of the present invention.

1 MFP (image forming device)
24 developing device 241 container (developer container)
242, 243 Stirring member (stirring section)
246 Stirring motor (stirring section)
281 Lower limit side toner sensor (fourth detection unit, lower limit side developer sensor)
282 Upper limit side toner sensor (second detection unit, upper limit side developer sensor)
901 Sub-determination unit (second / fourth detection unit, upper limit / lower limit developer sensor)
910 Current sensor (first / third detector, upper limit / lower limit current detector)
921 Lower limit comparator (third detector, lower limit current detector)
922 Upper limit side comparator (first detection unit, upper limit side current detection unit)
931 shortage detection unit (third detection unit, lower limit current detection unit)
932 Excessive detection unit (first detection unit, upper limit current detection unit)
940 Main judgment part (insufficient judgment part, excessive judgment part)
941 Toner replenishment control unit (replenishment stop control unit, replenishment start control unit)

Claims (7)

The developer accommodating container in a developing device, comprising: a developer accommodating container; an agitating unit for agitating the developer in the developer accommodating container; and a developing unit for developing an image with the developer in the developer accommodating container. A determination device for determining the amount of developer in
A first detection unit for detecting that the magnitude of the resistance applied to the stirring unit exceeds an upper limit during operation of the stirring unit;
A second detector for detecting the developer at the upper limit position in the developer container;
When the detection results of the first and second detection units indicate that the magnitude of the resistance exceeds the upper limit value and the developer is present at the upper limit position, it is determined that the developer is excessive. A determination unit;
A determination apparatus comprising: A third detection unit for detecting that the magnitude of the resistance falls below a lower limit;
A fourth detector for detecting the developer at the lower limit position in the developer container;
If the detection results of the third and fourth detection units indicate that the magnitude of the resistance falls below the lower limit value or that there is no developer at the lower limit position, an insufficient determination is made that the developer is insufficient. And
The determination apparatus according to claim 1, further comprising: The developer accommodating container in a developing device, comprising: a developer accommodating container; an agitating unit for agitating the developer in the developer accommodating container; and a developing unit for developing an image with the developer in the developer accommodating container. A determination device for determining the amount of developer in
An upper limit current detection unit for detecting that the current value required for the operation of the stirring unit exceeds the upper limit;
A piezoelectric vibration type upper limit side developer sensor for detecting the developer at the upper limit position in the developer container;
When the detection results of the upper limit current detection unit and the upper limit developer sensor indicate that the current value exceeds the upper limit value and the developer is present at the upper limit position, it is determined that the developer is excessive. An excessive determination unit to perform,
A determination apparatus comprising: A lower limit current detector for detecting that the current value has fallen below a lower limit;
A piezoelectric vibration type lower limit side developer sensor for detecting the developer at the lower limit position in the developer container;
If the detection result of the lower limit side current detector and the lower limit developer sensor indicates that the current value is below the lower limit value or that there is no developer at the lower limit position, it is determined that the developer is insufficient. A shortage determination unit;
The determination device according to claim 3, further comprising: A developer replenishing unit for replenishing the developer to a developing device comprising a developer containing container and a stirring unit for stirring the developer in the developer containing container;
The determination apparatus according to claim 1 or 3, wherein an amount of the developer in the developer container is determined.
A replenishment stop control unit for stopping developer replenishment by the developer replenishment unit when the excess determination unit determines that the developer is excessive;
A developer supply device comprising: A developer replenishing unit for replenishing the developer to a developing device comprising a developer containing container and a stirring unit for stirring the developer in the developer containing container;
The determination apparatus according to claim 2 or 4, wherein an amount of the developer in the developer container is determined.
A replenishment start control unit for starting developer replenishment by the developer replenishment unit when the deficiency determination unit determines that the developer is deficient;
A replenishment stop control unit for stopping developer replenishment by the developer replenishment unit when the excess determination unit determines that the developer is excessive;
A developer supply device comprising: A developing device comprising: a developer container; a stirring unit that stirs the developer in the developer container; and a developing unit that develops an image with the developer in the developer container;
The developer replenishing device according to claim 5 or 6,
An image forming apparatus comprising:

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