JP5451241B2 - Developer detection apparatus and image forming apparatus - Google Patents

Description

  The present invention includes a developer storage container that stores a developer, a toner sensor that is attached to a wall of the developer storage container and can detect the presence or absence of the developer inside, and a wiper that cleans the toner sensor. The present invention relates to an agent detection device and an image forming apparatus.

  Conventionally, an image forming apparatus is provided with a developing device for developing toner on a photosensitive drum. The developing device is provided with a developer transport device having a developer storage container for storing toner. The developer storage container may include a main toner container that can be attached to and detached from the main body of the image forming apparatus, and a sub toner container that is built into the main body of the image forming apparatus and cannot be attached and detached. In this case, the toner follows the path of the main toner container, the sub toner container, and the developing device, and is developed to the photosensitive drum. The sub-toner container is provided so that an image can be formed on the recording material for a while after it is detected that there is no toner in the main toner container. As an invention for detecting the presence / absence of toner inside such a sub-toner container, there is an invention described in Patent Document 1. In addition, there is an invention described in Patent Document 2 as a sensor for detecting the presence or absence of toner in the developer storage container.

  In Patent Document 1, a toner sensor is provided in a sub-toner container, a cleaning member reciprocates on a detection surface of the toner sensor, and the cleaning member stops at a fixed position outside the detection surface after the reciprocation. An invention relating to containers is disclosed. According to the invention described in Patent Document 1, the toner sufficiently loosened inside the main toner container moves to the inside of the sub toner container, so that the toner is prevented from adhering to the detection surface of the toner sensor. The As a result, erroneous detection of toner is prevented.

  Patent Document 2 discloses an invention relating to a toner sensor using a two-terminal piezoelectric element provided in a developer storage container. In the invention described in Patent Document 2, the toner sensor includes a two-terminal piezoelectric element to which toner is applied as a load, and an oscillation circuit that sweeps the two-terminal piezoelectric element in a frequency range including a resonance frequency of the piezoelectric element. Prepare. In addition, the toner sensor has a driving circuit that is driven to generate an output voltage corresponding to the impedance of the two-terminal piezoelectric element, a reference voltage is set in advance, and the reference voltage is compared with the output voltage. Comparing means for determining the presence or absence of toner. According to the invention described in Patent Document 2, it is possible to reduce the size of the developer storage container.

  According to the configuration including the configuration of the toner sensor described in Patent Document 2 described above and the configuration of cleaning the sensor surface of the toner sensor described in Patent Document 1, the sub-toner container can be reduced in size.

JP 2006-047778 A JP-A-6-27065

  However, in the inventions described in Patent Documents 1 and 2, the cleaning member reciprocates at a predetermined angle on the detection surface of the toner sensor, and then waits outside the detection surface. For this reason, an extra standby space for the cleaning member is secured, which prevents the developer storage container from being reduced.

  Further, the cleaning member is susceptible to toner pressure at both ends after reciprocating, and is deformed over time, so that the movable range that can function on the detection surface of the toner sensor is substantially narrowed. Sometimes it stopped inside the detection surface. As described above, when the cleaning member stops on the inner side of the detection surface of the toner sensor, erroneous detection of the toner sensor may occur.

  In view of the above circumstances, it is an object of the present invention to provide a developer detection device that can reduce the standby space of the cleaning member and reduce the size of the developer storage container.

In order to solve the above problems, a developer detection device of the present invention includes a developer storage container capable of storing a developer, a developer attached to a wall of the developer storage container, and a developer inside the developer storage container. Developer presence / absence detection means that exhibits different driving characteristics depending on the presence / absence of the developer, a cleaning member that cleans while moving the surface of the developer presence / absence detection means, a drive mechanism that drives the cleaning member, and the developer by the drive mechanism A controller for determining the presence or absence of the developer in the developer storage container based on the drive characteristics indicated by the developer presence / absence detection means in a state where at least a part of the cleaning member is stopped on the surface of the presence / absence detection means; has the driving characteristics of the developer presence detection means, wherein a characteristic of the output voltage of the developer presence detection means, said controller includes a plurality of stop positions of the surface of the developer presence detection means Based on the measurement result of the maximum output voltage measurement unit, the maximum output voltage measurement unit that measures the maximum output voltage at which the output voltage of the developer presence / absence detection means becomes the maximum value every time the cleaning member is stopped at A first stop position that selects a maximum output voltage position at which the output voltage of the developer presence / absence detecting means is maximized from a plurality of stop positions, and controls driving of the cleaning member so as to stop at the maximum output voltage position. And a control unit .
Further, another developer detection device of the present invention is attached to a developer storage container capable of storing a developer and a wall of the developer storage container, and differs depending on the presence or absence of the developer inside the developer storage container. A developer presence / absence detecting means exhibiting driving characteristics; a cleaning member for cleaning while moving the surface of the developer presence / absence detecting means; a drive mechanism for driving the cleaning member; and the developer presence / absence detecting means by the drive mechanism. A controller for determining the presence / absence of a developer inside the developer storage container based on a driving characteristic indicated by the developer presence / absence detecting means in a state where at least a part of the cleaning member is stopped on the surface. The driving characteristic of the developer presence / absence detecting means is a frequency characteristic of the developer presence / absence detecting means, and the tip of the cleaning member is disposed so as to be in contact with the surface area of the developer presence / absence detecting means, The controller includes a first frequency corresponding to one maximum value of the output voltage of the developer presence / absence detection means each time the cleaning member is stopped at a plurality of stop positions on the surface of the developer presence / absence detection means, and the like And a minimum absolute value position at which the absolute value of the difference between the first frequency and the second frequency is minimized based on the measurement result of the frequency measurement unit, and a frequency measurement unit that measures the second frequency corresponding to the local maximum value And a second stop position control unit that controls driving of the cleaning member so as to stop at the minimum absolute value position.

  As described above, according to the present invention, even if the cleaning member stops on the surface of the developer presence / absence detection unit, the presence / absence of the developer in the developer storage container based on the driving characteristics of the developer presence / absence detection unit. Is judged. Therefore, it is not necessary to stop the cleaning member outside the surface of the developer presence / absence detecting means. As a result, the waiting space for the cleaning member is reduced, and the developer storage container is reduced in size.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus including a developer conveyance device according to Embodiment 1 of the present invention. It is sectional drawing which shows the structure of a developing agent conveyance apparatus. FIG. 4 is a perspective view illustrating configurations of a toner sensor and a cleaning member drive mechanism. FIG. 3 is a block diagram illustrating a configuration of a developer presence / absence detecting unit. It is a graph which shows the frequency characteristic of a piezoelectric element. It is a circuit diagram of a comparator circuit. It is a top view which shows the stop position which stops the cleaning member on the surface of a detection surface. 6 is a graph showing a relationship between an output voltage and a frequency when a cleaning member stops at each stop position on the surface of a detection surface in a state where no toner is present inside a sub toner container. It is a top view which shows the stop position which stops the cleaning member on the surface of a detection surface. It is a flowchart which shows the stop position setting control process of the cleaning member by a controller. It is a graph which shows the relationship between a stop position and a peak output value. FIG. 10 is a plan view and a side view illustrating a positional relationship between a cleaning member and a toner sensor included in a developer conveyance device according to a second embodiment. 6 is a graph showing a relationship between an output voltage and a frequency when a cleaning member stops at each stop position on the surface of a detection surface in a state where no toner is present inside a sub toner container. It is a top view which shows the stop position which stops the cleaning member on the surface of a detection surface. It is a graph which shows the relationship of the frequency difference value of a stop position, the 1st frequency corresponding to a 1st peak value, the 2nd frequency corresponding to a 2nd peak value, a 1st frequency, and a 2nd frequency.

  Hereinafter, exemplary embodiments of the present invention will be described in detail by way of example. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions, there are particularly specific descriptions. As long as there is not, it is not the meaning which limits the scope of the present invention only to them.

  FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus 99 including a developer storage container according to Embodiment 1 of the present invention. As shown in FIG. 1, the image forming apparatus 99 includes image forming units 100 </ b> Y to 100 </ b> Bk that form images on the recording material P. Each of the image forming units 100Y to 100Bk includes four photosensitive drums 101 that are four “image carriers” corresponding to yellow Y, magenta M, cyan C, and black Bk. Around each photosensitive drum 101, a primary charging device 102, an exposure device 103, a developer conveying device 104, a developing device 105, a transfer roller 106, and a cleaning device 114 are provided. The image forming apparatus 99 includes a transfer belt 107 and a plurality of rollers 107 a and 107 b that suspend the transfer belt 107. A fixing device 113 is disposed on the right side of the plurality of rollers 107a and 107b.

  First, the primary charging device 102 charges the surface of the photosensitive drum 101 uniformly. Thereafter, the exposure device 103 irradiates the photosensitive drum with light to write an electrostatic image. Subsequently, only the toner in the developer is developed on the surface of the photosensitive drum 101 by the developing device 105. The developed toner is transferred to the recording material P, and the recording material P is separated from the photosensitive drum 101. Finally, the fixing device 113 applies heat and pressure to the recording material P to fix the image, and the image is output to the recording material P.

  The “developer” includes a one-component composition (only toner particles) and a two-component composition (carrier particles and toner particles), and any of them may be used. Here, a case where only toner particles having a single component composition are used will be described.

  FIG. 2 is a cross-sectional view and a front view showing the configuration of the developer conveying device 104. FIG. 2A is a cross-sectional view of the photosensitive drum 101, the developing device 105, and the developer conveying device 104 cut in a direction perpendicular to the axis of the photosensitive drum 101. FIG. 2B is a front view of the developer transport device 104. As shown in FIG. 2, the developer conveying device 104 is built in the main toner container 2 which is a “first developer storage container” which is detachable from the image forming apparatus main body 99A, and the image forming apparatus main body. A sub-toner container 1 which is a “second developer storage container”. Both the main toner container 2 and the sub toner container 1 are the same in that they can store toner as “developer”. However, in the case of the sub toner container 1, the toner is preliminarily stored so that an image can be formed on the recording material P for a while even when the toner in the main toner container 2 runs out. The The developer conveying device 104 functions as a “developer detecting device” as described later.

  Further, the bottom of the sub toner container 1 is continuous with the toner transport pipe 3 extending in the horizontal direction in FIG. 2A, and the sub toner container 1 and the toner transport pipe 3 are integrally formed. A developing device 105 is provided on the lower left side of the toner conveying pipe 3, and the developing device 105 has a developing container 11. The main toner container 2 and the sub toner container 1 are connected by a toner supply port 2 a formed in the main toner container 2. Further, the toner conveying pipe 3 and the developing container 11 are connected by a toner receiving hole 13 formed in the upper part of the developing container 11.

  A stirring blade 12 is rotatably disposed inside the main toner container 2. A toner stirring member 6 is rotatably disposed inside the sub toner container 1. A toner conveying screw 4 is rotatably disposed inside the toner conveying pipe 3. The toner stored inside the main toner container 2 is conveyed inside the main toner container 2 by driving the stirring blade 12 and is replenished from the toner supply port 2 a to the sub toner container 1. The toner that has moved into the sub-toner container 1 is agitated by the toner agitating member 6 inside the sub-toner container 1 and then conveyed by the toner conveying screw 4 inside the toner conveying pipe 3 to be developed from the toner receiving hole 13 through the developing container 11. To be replenished.

  In the developing device 105, the developing sleeve 11 a is disposed close to the photosensitive drum 101 and rotates in the reverse direction or the same direction as the photosensitive drum 101. The developer (shown by dots) is set so that development can be performed in contact with the photosensitive drum 101. The configurations of the main toner container 2, the sub toner container 1, the toner conveying screw 4, and the developing container 11 described above will be described in detail below.

  First, the internal configuration of the main toner container 2 will be described in detail. An agitating blade 12 is disposed inside the main toner container 2 so as to be rotatable about a predetermined central axis, and is rotated by driving of a driving means 12a. As shown in FIG. 2B, the stirring blade 12 has a function of loosening the toner in order to prevent the toner from solidifying inside the main toner container 2 by rotating. Further, the stirring blade 12 has a function of conveying the toner inside the main toner container 2 in the longitudinal direction (direction parallel to the paper surface) toward the toner supply port 2 a communicating with the sub toner container 1. Further, the stirring blade 12 has a function of pushing toner out of the toner supply port 2a and dropping it into the sub-toner container 1. As the stirring blade 12, for example, a sheet material such as PET is used.

  The main toner container 2 may be detachable from the image forming apparatus main body 99A or may be fixed to the image forming apparatus main body 99A. The main toner container 2 is generally called a developer cartridge when it is detachable. When the toner runs out, the main toner container 2 is replaced with the main toner container 2 to be filled with toner. When the image forming apparatus main body 99A is fixed, the main toner container 2 is directly filled with toner from another toner container.

  Next, the internal configuration of the sub toner container 1 will be described in detail. The sub-toner container 1 is positioned as an intermediate container for supplying toner stored in the main toner container 2 to the developing container 11. The upper part of the sub toner container 1 is connected to the toner supply port 2 a of the main toner container 2. Therefore, the sub toner container 1 can receive supply of toner inside the main toner container 2. The bottom portion of the sub-toner container 1 has a side surface protruding in a substantially horizontal direction, is formed in a cylindrical shape, and is continuous with a toner transport pipe 3 capable of transporting toner. A toner agitating member 6 that is movably provided is provided at the bottom and the center of the upper part of the sub-toner container 1, and the toner agitating member 6 is rotated or rotated to act to loosen the toner. Has been. A toner conveying screw 4 as a “developer conveying means” is rotatably provided from the bottom of the sub toner container 1 to the inside of the toner conveying pipe 3. A spiral surface is formed on the toner conveying screw 4. At the tip of the toner conveying screw 4, a driver 5, which is “driving means” that rotationally drives the toner conveying screw 4 is provided.

  Next, the internal configuration of the toner transport pipe 3 will be described in detail. The toner conveying screw 4 is rotated by a driver 5. In order to maintain the T / C ratio between the toner particles inside the developing container 11 and the magnetic carrier, according to the toner density detection result inside the developing container 11, the controller 202 corresponds to the toner consumed by the development. The number of rotations or the rotation time is set according to the amount of toner. The controller 202 is described in FIG. The controller 202 stops the rotation of the toner conveying screw 4 when the set number of rotations or rotation time is reached. As a result, as much toner as requested by the developing device 105 is conveyed, and the toner is supplied to the developing container 11.

  At this time, the toner conveying screw 4 has a constant toner conveying amount per rotation or unit time according to the size thereof, and the controller 202 determines the number of rotations or the rotation time according to the required amount. Control to calculate is possible. Here, since the amount of toner transported by the toner transport screw 4 is proportional to the number of rotations, in order to set the rotation time, the toner transport screw 4 is always rotated at a constant speed by the driver 5. It is a premise. Further, if a means for counting the number of rotations is provided, the rotation speed of the toner conveying screw 4 can be set by the number of rotations, whether or not constant.

  The presence / absence of toner in the sub toner container 1 is always detected by the toner sensor 7 provided in the sub toner container 1, and the toner is replenished from the main toner container 2 to the sub toner container 1 in the presence of toner. When there is no toner, the user is notified of this. As described above, the toner is constantly loosened in the sub-toner container 1 by the rotation of the toner stirring member 6. At the same time, a cleaning member 8 is provided on the detection surface 7a of the toner sensor 7, and the surface of the detection surface 7a is constantly cleaned by the cleaning member 8. This cleaning member 8 functions as a wiper for wiping on the detection surface 7a. The toner is then conveyed from the toner receiving hole 13 to the developing container 11.

  Next, the internal configuration of the developing container 11 will be described in detail. The developing container 11 corresponds to the housing of the developing device 105. A cylindrical developing sleeve 11a provided in parallel to the photosensitive drum 101 is provided in an opening provided in a portion of the developing container 11 facing the photosensitive drum 101, and is fixedly disposed in the developing sleeve 11a. The magnet roller 11b is incorporated. The developing device 105 is partitioned in parallel with the developing sleeve 11a, and is divided into a developing chamber 11c that supplies a developer to the developing sleeve 11a and an agitating chamber 11d that is provided with a toner receiving hole 13 in the upper portion. The developing chamber 11c is provided with a developing screw 11e, and the stirring chamber 11d is provided with a stirring screw 11f. The developing chamber 11c and the stirring chamber 11d communicate with each other at the ends of the developing screw 11e and the stirring screw 11f. The mixture is stirred while circulating.

  Therefore, the toner replenished from the toner receiving hole 13 in the stirring chamber 11d is mixed with the toner already in the developing container 11 and the developer containing the carrier, and is transported to the developing chamber 11c in a uniform state. , And supplied to the developing sleeve 11a. Then, at the opening of the developing container 11 provided with the developing sleeve 11a, the developer sleeve 11a is restricted to a position opposite to the upstream side in the rotational direction of the developing sleeve 11a in order to form a thin layer on the surface of the developing sleeve 11a. A blade 11g is arranged. Then, the developer carried on the developing sleeve 11a is conveyed to the surface of the photosensitive drum 101 by the rotation of the developing sleeve 11a, and on the photosensitive drum 101 by a developing bias applied to the developing sleeve 11a from a power source (not shown). The formed electrostatic latent image is developed.

  An amount of toner commensurate with the toner consumed by the developing operation of the developing device 105 by the developer conveying device 104 passes through the main toner container 2, the sub toner container 1, the toner conveying pipe 3, and the toner receiving hole 13, and the stirring screw Dropped into the stirring chamber 11d having 11f.

  The developer used in the developing device 105 will be described. The developer container 11 contains a developer in which toner particles and a magnetic carrier are mixed. The mixing ratio of the toner particles and the magnetic carrier (hereinafter referred to as “T / C ratio”) is constant by replenishing the toner by the developer conveying device 104 according to the toner density detection result in the developing container 11. It is kept in. At this time, various methods for detecting the mixing ratio of the toner particles and the magnetic carrier in the developing container 11, that is, detecting the toner concentration and maintaining the concentration have been put to practical use. Is called.

  The developer conveying device 104 that is a “developer detecting device” mainly includes a sub toner container 1 that conveys the developer, a toner sensor 7, a cleaning member 8, a drive mechanism 201, and a controller 202. The toner sensor 7 is attached to the wall of the sub toner container 1 and exhibits different driving characteristics depending on the presence or absence of toner inside the sub toner container 1. The toner sensor 7 electrically detects the presence or absence of toner. The cleaning member 8 cleans the detection surface 7a of the toner sensor 7 while moving. The cleaning member 8 operates in conjunction with the toner stirring member 6 to clean the detection surface 7 a of the toner sensor 7. The drive mechanism 201 drives the cleaning member 8. The controller 202 determines the presence / absence of toner in the sub-toner container 1 based on the drive characteristics indicated by the toner sensor 7 in a state where at least a part of the cleaning member 8 is stopped on the detection surface 7a of the toner sensor 7 by the drive mechanism 201. judge. In addition, the developer conveying device 104 includes a driver 5 that drives the toner conveying screw 4 and a toner stirring member 6 that is movably provided inside the sub toner container 1. Further, the developer transport device 104 includes a position sensor 9 that detects a stop position of the cleaning member 8 and a sensor flag 10 that is a detected member detected by the position sensor 9.

  Next, the toner sensor 7 will be described in detail. A piezo sensor is used as the “piezoelectric sensor” for the toner sensor 7 as “developer presence / absence detecting means”. A piezo sensor is a sensor using a piezoelectric element. When the detection surface 7a is vibrated at a constant frequency, the toner sensor 7 determines that the detection surface 7a is pressed by toner when the detection surface 7a receives pressure and the vibration is reduced. Signal. On the other hand, when the vibration increases without the detection surface 7a receiving pressure, the toner sensor 7 determines that the detection surface 7a is not pressed by the toner and generates vibration without toner.

  A toner sensor 7 is disposed on the wall surface of the sub-toner container 1 and a cleaning member 8 is disposed for cleaning the detection surface 7a. The cleaning member 8 presses a member such as a wire with a certain pressure on the detection surface 7a. ing. The pressure of the cleaning member 8 is set to a level that does not adversely affect the toner inside the sub toner container 1. In the present embodiment, the cleaning member 8 is obtained by plating iron having a diameter of 0.35 mm.

  In the sub-toner container 1, since the toner already loosened to some extent in the main toner container 2 is supplied, there is little sticking of the toner to the detection surface 7a, and the pressure on the detection surface 7a of the cleaning member 8 can be lowered. Is unlikely to occur. Further, by disposing the toner sensor 7 in the sub-toner container 1, it becomes possible to eliminate the toner sensor 7 from the main toner container 2 that is normally used for replacement, thereby reducing the cost of the main toner container 2 and the cost required for toner replacement. (Running cost) can be reduced. Furthermore, since the number of toner replacements increases as the life of the main body increases, reducing the running cost can reduce the burden on the user.

  The cleaning member 8 is installed on the toner stirring member 6, and the toner stirring member 6 is pivotally supported on the sub-toner container 1. The rotating shaft 6a of the toner stirring member 6 extends to the outside of the sub toner container 1, and a sensor flag 10 is fixed to a part of the rotating shaft 6a. The sensor flag 10 may be integrated with the rotation shaft 6a. A position sensor 9 for detecting the position of the sensor flag 10 is arranged. For example, a photo sensor is used as the position sensor 9. By stopping the rotation shaft 6a after a predetermined time from the state where the sensor flag 10 of the position sensor 9 is turned off, the rotation shaft 6a can always be stopped at the same position.

  FIG. 3 is a perspective view illustrating configurations of the toner sensor 7 and the driving mechanism 201 of the cleaning member 8. As shown in FIG. 3, the drive mechanism 201 includes a driver 5 that drives and stops the cleaning member 8. As shown in FIG. 3, the protrusion of the driver 5 meshes with the elongated hole of the sensor flag 10, and the sensor flag 10 is designed to reciprocate once at a fixed angle when the driver 5 makes one rotation. Yes. As the sensor flag 10 reciprocates, the cleaning member 8 also reciprocates at a constant angle.

  Note that the position sensor 9 detects one rotation of the driver 5. For example, a photosensor may be used as the position sensor 9, and one rotation of the driver 5 is detected by the sensor flag 10 shielding the optical axis. Of course, one rotation may be detected at an unshielded position.

  A configuration in which the combination of the sensor flag 10 and the photosensor is not used is also possible. That is, when a stepping motor or the like having a high rotational accuracy and a small time delay at the time of start and stop is used for at least the drive motor as the “drive means”, the cleaning member 8 is placed at a predetermined position on the surface of the detection surface 7a every time. Can be operated to stop.

  The cleaning member 8 has a bent portion on the proximal end side, and the bent portion is engaged with the toner stirring member 6. When the sensor flag 10 is driven by the driver 5, the cleaning member 8 reciprocates on the detection surface 7a, and the cleaning member 8 cleans the detection surface 7a.

  Here, referring back to FIG. 2, the operation of replenishing toner from the main toner container 2 to the sub toner container 1 when the toner in the sub toner container 1 decreases as the toner is consumed will be described. The toner stirring member 6 has a function of loosening the toner while rotating in order to prevent the toner from solidifying inside the sub toner container 1. The toner conveying screw 4 has a function of conveying the toner in the sub toner container 1 toward the toner receiving hole 13 communicating with the developing container 11 in the longitudinal direction (direction parallel to the paper surface), and the toner from the toner receiving hole 13. It has a function of extruding and dropping to the developing container 11.

  After the toner sensor 7 detects the absence of toner, even if the agitation blade 12 inside the main toner container 2 is operated, the toner remains in the sub-toner container 1 and the main toner container 2 when there is no toner. It is determined that the toner has actually run out, rather than being solidified. After detecting the presence of toner, toner supply is continued from the sub-toner container 1 via the toner conveying screw 4.

  If the toner sensor 7 does not detect the presence of toner even if the stirring blade 12 of the main toner container 2 is rotated for a sufficient time, the toner is not replenished to the sub toner container 1. That is, it can be determined that the main toner container 2 has run out of toner, and the user is notified of the absence of toner through display means such as an operation panel (not shown).

  Further, since the output of the toner sensor becomes unstable while the cleaning member 8 is moving on the surface of the detection surface 7a, the detection circuit (not shown) detects the presence or absence of toner only when the cleaning member 8 is stopped. To do.

  FIG. 4 is a block diagram showing a configuration of the developer presence / absence detecting means 30. Hereinafter, a toner presence / absence detection method using a piezoelectric element used as the toner sensor 7 will be described with reference to FIG. The developer presence / absence detection means 30 includes a two-terminal piezoelectric element 31 having two terminals T1 and T2 serving as toner sensors provided on the front surface and the back surface. The developer presence / absence detecting means 30 includes a sweep oscillation circuit 32 that sweeps the two-terminal piezoelectric element 31 in a frequency range including the resonance frequency of the two-terminal piezoelectric element 31 so that the impedance changes.

  The developer presence / absence detecting means 30 is connected in series to the two-terminal piezoelectric element 31 and the sweep oscillation circuit 32, and is driven by the sweep oscillation circuit 32 to generate an output voltage proportional to the impedance. A constant current drive circuit 33 is provided. Further, the developer presence / absence detecting means 30 sets a reference voltage in advance and compares the reference voltage with the output voltage to determine the presence / absence of toner, and the result of the comparison means 34 such as a comparator circuit. Output means 35 comprising a display, a meter, etc.

  FIG. 5 is a graph showing frequency characteristics of the piezoelectric element. FIG. 5A is a graph showing the frequency characteristics of the piezoelectric element when there is no load. FIG. 5B is a graph showing the frequency characteristics of the piezoelectric element when there is a load. When the two-terminal piezoelectric element 31 is swept and oscillated in the frequency range including the resonance frequency by the sweep oscillation circuit 32, the impedance of the two-terminal piezoelectric element 31 changes depending on the presence or absence of toner as powder. For example, when the toner runs out or the remaining amount thereof decreases, the impedance Z changes with the relationship shown in FIG. 5A with respect to the sweep frequency f. On the other hand, when there is a sufficient amount of toner, the impedance Z changes with the relationship shown in FIG. 5B with respect to the sweep frequency f. Here, the impedance characteristic of the toner sensor 7 that is “driving characteristic” is used, but the present invention is not limited to this, and the phase characteristic of the toner sensor 7 that is “driving characteristic” may be used.

FIG. 5C is a graph showing the relationship between the reference voltage V _R for determining the presence / absence of toner and the graphs of FIGS. 5A and 5B described above. When the two-terminal piezoelectric element 31 is driven by the resistor R as the constant current driving circuit 33, the two-terminal piezoelectric element 31 corresponds to the impedance characteristics shown in FIGS. 5A and 5B depending on the presence or absence of toner. The output voltage having the relationship as shown in FIG.

  FIG. 6 is a circuit diagram of a comparator circuit 34A as the comparison means 34. The comparator circuit 34A as the comparison means 34 has a reference voltage VR in advance as shown in FIG. 6, and compares the output voltage V from the two-terminal piezoelectric element 31 and the reference voltage VR within the range of the sweep frequency. . The comparator circuit 34A determines that there is no toner when the output voltage V becomes larger than the reference voltage VR as shown in FIG. 5C, and the output voltage V is always within the sweep frequency range from the reference voltage VR. If it is lower, it is determined that there is toner.

  As a result of the determination by the comparator circuit 34A (see FIG. 4), the output voltage is applied to the output means 35, and the presence or absence of powder is displayed on the display of the output means 35 and the instrument. Alternatively, it is sent as an input signal to another control circuit.

  FIG. 7 is a plan view showing a stop position at which the cleaning member 8 is stopped on the surface of the detection surface 7a. In FIG. 7, all the positions are drawn with a solid line, but there is actually only one cleaning member. As shown in FIG. 7, the cleaning member (wiper) 8 is formed of a linear member. Here, it is assumed that the cleaning member 8 is stopped at the first stop position J and the second stop position K on the surface of the detection surface 7 a of the toner sensor (vibrating plate) 7. The cleaning member 8 is operated when there is no toner in the sub toner container 1. When the cleaning member 8 is stopped on the surface of the detection surface 7a as described above, the frequency response indicated by the detection surface 7a is different from the case where powder such as toner is gradually accumulated in a vibrating plate shape. This is known as a result of the experiment. In this case, the cleaning member is set to a length that straddles the detection surface 7a.

  The controller 202 includes a maximum output voltage measurement unit 202A and a first stop position control unit 202B. The maximum output voltage measuring unit 202 </ b> A measures the maximum output voltage at which the output voltage of the toner sensor 7 becomes the maximum value every time the cleaning member 8 is stopped at a plurality of stop positions of the detection surface 7 a of the toner sensor 7. The first stop position control unit 202B selects a maximum output voltage position at which the output voltage of the toner sensor 7 is maximum from a plurality of stop positions based on the measurement result of the maximum output voltage measurement unit 202A, and the maximum output voltage The driving of the cleaning member 8 is controlled so as to stop at the position.

  FIG. 8 is a graph showing the relationship between the output voltage and the frequency when the cleaning member 8 stops at each stop position on the surface of the detection surface 7a in a state where no toner is present inside the sub toner container 1. When the cleaning member 8 stops at the first stop position J in FIG. 7, a graph showing the drive characteristics of 8J in FIG. 8 is output. When the cleaning member 8 stops at the second stop position K in FIG. 7, a graph showing the drive characteristics at 8K in FIG. 8 is output. That is, even when the cleaning member 8 having the same mass becomes a load, different characteristics such as the drive characteristic 8J or the drive characteristic 8K are derived depending on whether the cleaning member 8 is the first stop position J or the second stop position K of the detection surface 7a. The It can be said that the drive characteristics 8J and the drive characteristics 8K of the toner sensor 7 here are characteristics of the output voltage of the toner sensor 7.

  In the case of the drive characteristic 8J, the output voltage is lower than the reference voltage VR at the frequency f1, but the output voltage is higher than the reference voltage VR at the frequency f2. Thus, when the output voltage is higher than the reference voltage VR, the presence of the cleaning member 8 on the surface of the detection surface 7a has little influence on detection of the presence or absence of toner. In the case of the drive characteristic 8K, the output voltage is lower than the reference voltage VR at both the frequency f1 and the frequency f2. Thus, when the two peak values of the output voltage are both lower than the reference voltage VR, it is impossible to detect the absence of toner, and therefore the presence of the cleaning member 8 on the surface of the detection surface 7a is The detection of the presence or absence of toner has a great influence.

  Thus, when the change in the waveform is monitored while changing the stop position of the cleaning member 8 on the surface of the detection surface 7a, the output voltage is output at the first stop position (here, the first stop position J) where the influence of the cleaning member 8 is small. The peak value of increases. On the other hand, the peak value of the output voltage is low at the stop position where the influence of the cleaning member 8 is large (here, the second stop position K).

  FIG. 9 is a plan view showing a stop position at which the cleaning member 8 is stopped on the surface of the detection surface 7a. In FIG. 9, all the positions are drawn with solid lines, but there is actually only one cleaning member 8. As shown in FIG. 9, the cleaning member 8 has a first stop position D1 (n = 1) first, a second stop position D2 (n = 2), and second on the surface of the detection surface 7a. Secondly, the operation is stopped in order at the third stop position D3 (n = 3). Thereafter, the cleaning member 8 is sequentially stopped at the fourth stop position D4 (n = 4) fourth and the fifth stop position D5 (n = 5) fourth on the surface of the detection surface 7a.

  FIG. 10 is a flowchart showing a stop position setting control process for the cleaning member 8 by the controller 202. The controller 202 of the developer conveying device 104 performs stop position setting control of the cleaning member 8 as shown in FIG. 9 using the above-described driving characteristics. Hereinafter, the stop position setting control of the controller 202 will be described with reference to FIGS. 9 and 10.

  This will be explained in time series. As shown in FIG. 10, the controller 202 first starts stop position setting control (S1). The controller 202 recognizes the position information n = 1 in order to move the cleaning member 8 to the nth nth stop position (S2). The controller 202 rotates the motor for a predetermined time after turning off the sensor flag, and moves the cleaning member 8 to the first stop position D1 (n = 1) for frequency setting (S3).

  The controller 202 displays the output voltage of the toner sensor 7 on the monitor while the cleaning member 8 is stopped at the first stop position D1 (n = 1) (S4). The controller 202 detects and stores the first peak value of the output voltage when the monitored waveform passes through the peak detection circuit (S5). Subsequently, the controller 202 detects the second peak value of the output voltage (S6). The controller 202 recognizes the position information n + 1 in order to move the cleaning member 8 to the n = n + 1th stop position (S7). The controller 202 determines whether or not the position information of the cleaning member 8 is n ≧ 6 (S8).

  If the result of the determination by the controller 202 (S8) is YES, the controller 202 compares the peak value of the output voltage with n = 1 to 5 (S9). The controller 202 determines the stop position of the cleaning member 8 (S10). The controller 202 moves the cleaning member 8 to the stop position (S11). The controller 202 stops the control (S12).

  If the result of determination by the controller 202 (S8) is NO, the controller 202 moves the cleaning member 8 to the next second stop position D2 (n = 2) for frequency setting (S3). The controller 202 again detects the first peak value and the second peak value, and stores them in association with the second stop position D2 (n = 2).

  Each time the peak value is detected, the controller 202 determines whether or not the set confirmation position has been reached, and then the third stop position D3 (n = 3), the fourth stop position D4 (n = 4), 5 Controls such as movement of the cleaning member 8 and detection of the peak value are repeated for the stop position D5 (n = 5). When the controller 202 repeats the movement of the cleaning member 8 and the detection of the peak value up to the number of stop positions for which the number of repetitions is set, that is, the fifth stop position D5 (n = 5), the movement of the cleaning member 8 and Stop detection of peak value. Then, the controller 202 compares the peak value of the output voltage from the first stop position D1 (n = 1) to the fifth stop position D5 (n = 5) (S9). The controller 202 selects the maximum peak value from all the stored peak values of the output voltage, and at the same time selects the optimum stop position of the cleaning member 8 (S10).

  FIG. 11 is a graph showing the relationship between the stop position and the peak value of the output voltage. The peak output in FIG. 11 is expressed as a percentage (%) of the output value when the maximum peak value of the output voltage when the cleaning member 8 is not disposed on the surface of the detection surface 7a is 100%. As shown in FIG. 11, at the first stop position D1 (n = 1), the peak output value indicates 40%. At the second stop position D2 (n = 2), the peak output value indicates 50%. At the third stop position D1 (n = 3), the peak output value indicates 30%. At the fourth stop position D1 (n = 4), the peak output value indicates 80%. At the fifth stop position D1 (n = 5), the peak output value indicates 45%. Among these, the optimum stop position of the cleaning member 8 is the fourth stop position D4 (n = 4) at which the peak output value is maximum. Therefore, when the controller 202 determines the stop position of the cleaning member 8 as the fourth stop position D4 (n = 4) and stops the cleaning member 8 at the fourth stop position D4 (n = 4), the control ends. (S12).

  As a result of the control of the controller 202, even when the cleaning member 8 stops on the surface of the detection surface 7a, a stop position is selected so that the influence of the cleaning member 8 on the output of the toner sensor 7 is minimized. be able to. As a result, the sub toner container 1 can be reduced in size, and the image forming apparatus 99 can be reduced in size.

  12A and 12B are a plan view and a side view illustrating the positional relationship between the cleaning member 18 and the toner sensor 7 included in the developer conveyance device according to the second embodiment. FIG. 12A is a plan view of the cleaning member 18 and the toner sensor 7, and FIG. 12B is a side view of the cleaning member 18 and the toner sensor 7. Among the configurations of the developer transport device of the second embodiment, the same configurations and effects as those of the developer transport device 104 of the first embodiment are denoted by the same reference numerals and description thereof is omitted as appropriate. Since the cleaning member 18 and the toner sensor 7 of the second embodiment can be applied to the same developer transport apparatus or image forming apparatus as the first embodiment, description of the developer transport apparatus and the image forming apparatus is omitted. The developer conveying device of the second embodiment is different from the developer conveying device 104 of the first embodiment in the following points. That is, in the developer conveyance device of Example 2, the length of the cleaning member 18 is shorter, the tip of the cleaning member 18 is disposed on the surface of the detection surface 7a, and the tip of the cleaning member 18. Is a point that is bent.

  As shown in FIG. 12A, the dimension of the cleaning member 18 is set shorter than the dimension of the cleaning member 8 described above. As shown in FIG. 12B, the cleaning member 18 has a cleaning member main body 18a and a bent front end 18b where the front end of the cleaning member main body 18a is bent. The cleaning member main body 18a and the bent tip 18b are formed continuously. A bent tip 18b, which is the “tip” of the cleaning member 8, is disposed so as to be in contact with the region of the detection surface 7a of the toner sensor 7. The following can be considered as the purpose of adopting such a configuration.

  When the cleaning member 18 is formed of a linear member, the portion of the cleaning member 18 that contacts the detection surface 7a is preferably arranged in parallel to the detection surface 7a and receives a uniform linear pressure from the detection surface 7a. . However, depending on the assembly accuracy and straightness of the cleaning member 18 and the toner sensor 7, so-called point pressure at which a part of the cleaning member 8 strongly contacts the detection surface 7a may be applied.

  Alternatively, there may be a case where it is better to arrange the tip of the cleaning member 18 inside the detection surface 7a as shown in FIG. 12 due to the downsizing of the developer conveying device or the image forming apparatus. However, in order to increase the strength of the tip of a linear member such as the cleaning member 18, it is necessary to bend the tip, and depending on the bent shape, high pressure may be applied to the bent tip 18b. In such a case, the cleaning member 18 vibrates due to the vibration of the developer conveying device or the image forming apparatus, the point pressure easily changes, and it is difficult to detect a stable toner amount.

  The controller 202 includes a frequency measurement unit 202C and a second stop position control unit 202D. Whenever the cleaning member 18 is stopped at a plurality of stop positions of the detection surface 7a of the toner sensor 7, the frequency measuring unit 202C first corresponds to one of the two maximum values of the output voltage of the toner sensor 7. The second frequency corresponding to the frequency and other maximum values is measured. Here, the first frequency is a value larger than the second frequency. Based on the measurement result of the frequency measurement unit 202C, the second stop position control unit 202D selects the minimum absolute value position where the absolute value of the difference between the first frequency and the second frequency is minimum from the plurality of stop positions. The driving of the cleaning member 8 is controlled so as to stop at the minimum absolute value position.

  FIG. 13 is a graph showing the relationship between the output voltage and the frequency when the cleaning member 18 stops at each stop position on the surface of the detection surface 7a in a state where there is no toner in the sub toner container 1. A graph 18j in FIG. 13 is a graph at the first stop position j of the cleaning member 18 with respect to the detection surface 7a in FIG. A graph 18k in FIG. 13 is a graph at the second stop position k of the cleaning member 18 with respect to the detection surface 7a in FIG. In FIG. 13, in the graph 18j of the first stop position j (n = 1), the first peak value 18j1 and the second peak value 18j2 are measured. In the graph 18k at the second stop position k (n = 2), the first peak value 18k1 and the second peak value 18k2 are measured. If the cleaning member 18 has a strong portion such as the bent tip 18b, the cleaning member 18 may apply a point pressure to the detection surface 7a. And as FIG. 13 shows, the phenomenon in which the position of a peak value shifts according to the position of the point pressure which the cleaning member 18 applies to the detection surface 7a is confirmed. It can be said that the drive characteristic of the toner sensor 7 in this case is the frequency characteristic of the toner sensor 7.

  The shift of the peak position is not large in the case of the first peak value 18j1 and the first peak value 18k1, but is significantly shifted in the case of the second peak value 18j2 and the second peak value 18k2.

  In other words, in the graph 18j of the first stop position j (n = 1), the distance between the first peak value 18j1 and the second peak value 18j2 is small in the frequency axis direction. On the other hand, in the graph 18k of the second stop position k (n = 2), the distance between the first peak value 18k1 and the second peak value 18k2 is large in the direction of the frequency axis. The relationship between this relationship and the determination of the presence / absence of toner in the controller 202 has been found as a result of experiments. That is, when the distance between the first peak value and the second peak value is narrow in the direction of the frequency axis, the cleaning member 18 has a large influence because the toner sensor 7 detects the presence or absence of toner. Absent. On the other hand, when the distance between the first peak value and the second peak value is wide in the direction of the frequency axis, the cleaning member 18 has a large influence because the toner sensor 7 detects the presence or absence of toner. .

  That is, when the distance between the first peak value and the second peak value is wide in the direction of the frequency axis, the first peak value 18k1 takes only a value smaller than the reference voltage VR. In this case, the toner sensor 7 cannot determine the absence of toner in the sub toner container 1. On the other hand, when the distance between the first peak value and the second peak value is narrow in the direction of the frequency axis, the first peak value 18j1 takes a value larger than the reference voltage VR. In this case, the toner sensor 7 can determine the absence of toner in the sub toner container 1.

  Using this characteristic, the presence or absence of toner is determined using a frequency band in which a peak value exceeding the reference voltage VR can be derived by changing the position where the cleaning member 8 applies the point pressure to the detection surface 7a. Are provided with frequency determination control. In the frequency determination control, the cleaning member 8 is stopped at a plurality of positions on the detection surface 7a, and the frequency characteristics of the toner sensor 7 are derived as waveforms on the monitor at each stop position. The frequency at which the first peak value is output and the frequency at which the second peak value is output are stored.

  For all stop positions, the first frequency corresponding to the first peak value and the second frequency corresponding to the second peak value are stored. Then, a frequency difference between the first peak value and the second peak value is taken, and the first frequency of the first peak value at the stop position where the difference is minimized becomes the detection frequency of the toner sensor 7. Is set.

  FIG. 14 is a plan view showing a stop position at which the cleaning member 18 is stopped on the surface of the detection surface 7a. As shown in FIG. 14, the cleaning member 8 is stopped at a plurality of positions on the surface of the detection surface 7a. The bent tip 18b of the cleaning member 18 includes a first stop position d1 (n = 1), a second stop position d2 (n = 2), a third stop position d3 (n = 3), and a fourth stop position d4 (n = 4) and stop in order at the fifth stop position d5 (n = 5).

  FIG. 15 is a graph showing the relationship between the stop position, the first frequency corresponding to the first peak value, the second frequency corresponding to the second peak value, and the frequency difference values of the first frequency and the second frequency. As shown in FIG. 15, at the first stop position d1 (n = 1), the first frequency corresponding to the first peak value is 6800 Hz, the second frequency corresponding to the second peak value is 6000 Hz, and the frequency difference The value is 800 Hz. Since this frequency difference value is the lowest among the first stop position d1 to the fifth stop position d5, the first stop position d1 is the optimum stop position for the cleaning member 8, and at this first stop position d1, It can be said that a frequency band of 6800 Hz to 6000 Hz is appropriate. At the second stop position d2 (n = 2), the first frequency corresponding to the first peak value is 6800 Hz, the second frequency corresponding to the second peak value is 5500 Hz, and the frequency difference value is 1300 Hz.

  At the third stop position d3 (n = 3), the first frequency corresponding to the first peak value is 6900 Hz, the second frequency corresponding to the second peak value is 5400 Hz, and the frequency difference value is 1500 Hz. At the fourth stop position d4 (n = 4), the first frequency corresponding to the first peak value is 6500 Hz, the second frequency corresponding to the second peak value is 5500 Hz, and the frequency difference value is 1000 Hz. At the fifth stop position d5 (n = 5), the first frequency corresponding to the first peak value is 6600 Hz, the second frequency corresponding to the second peak value is 5800 Hz, and the frequency difference value is 800 Hz. Since this frequency difference value is the lowest among the first stop position d1 to the fifth stop position d5, the fifth stop position d5 is the optimum stop position for the cleaning member 8, and at this fifth stop position d5, It can be said that the frequency band of 6600 Hz to 5800 Hz is appropriate.

  When such a sweep from 5800 Hz to 6600 Hz at the fifth stop position d5 was performed, the sweep time required for sampling every 10 Hz was about 9 ms. On the other hand, the sweep time when sweeping from 4000 Hz to 9000 Hz without frequency determination control was 81 ms. Therefore, when the sweep from 5800 Hz to 6600 Hz is performed, the sweep time can be shortened to about 1/9 compared with the case where the frequency determination control is not performed.

  Accordingly, the optimum stop position of the cleaning member 8 can be set in consideration of individual variations of the toner sensor 7 and the cleaning member 8 and assembly variations, and the detection time required for sensing can be shortened by narrowing the detection frequency. be able to.

  As described above, according to the invention of Example 1 or 2, even if the cleaning member 8 stops on the detection surface 7 a of the toner sensor 7, the toner inside the sub toner container 1 based on the driving characteristics of the toner sensor 7. The presence or absence of is determined. Accordingly, there is no need to stop the cleaning member 8 outside the detection surface 7a of the toner sensor 7, and the area for moving the cleaning member 8 is reduced. As a result, the standby space of the cleaning member 8 is reduced, and the sub-toner container 1 is reduced in size.

  According to the first embodiment, based on the measurement result of the maximum output voltage measurement unit 202A, the first stop position control unit 202B has a maximum output at which the output voltage of the toner sensor 7 is maximized among the plurality of stop positions. Select the voltage position. Then, the first stop position control unit 202B controls the driving of the cleaning member 8 so as to stop at the maximum output voltage position. Therefore, even when the cleaning member 8 is present on the detection surface 7a of the toner sensor 7 at the maximum output voltage position where the output voltage of the toner sensor 7 is maximum, the function of the toner sensor 7 is sufficiently exhibited. The The influence of the cleaning member 8 on the toner sensor 7 does not matter. As a result, erroneous detection of the presence or absence of toner due to the cleaning member 8 being disposed on the detection surface 7a of the toner sensor 7 is suppressed.

  According to the second embodiment, based on the absolute value of the difference between the first frequency and the second frequency measured by the frequency measuring unit 202C, the second stop position control unit 202D determines the absolute value from the plurality of stop positions. Select the minimum absolute value position that minimizes. Then, the second stop position control unit 202D controls the driving of the cleaning member 8 so as to stop at the minimum absolute value position. Therefore, even if the cleaning member 8 exists on the detection surface 7a of the toner sensor 7 at the minimum absolute value position where the absolute value of the frequency difference of the toner sensor 7 is minimum, the function of the toner sensor 7 is as follows. It is fully demonstrated. The influence of the cleaning member 8 on the toner sensor 7 does not matter. As a result, erroneous detection of the presence or absence of developer due to the cleaning member 8 being disposed on the detection surface 7a of the toner sensor 7 is suppressed.

  [Other Examples]

  The entire detection surface 7a to which the cleaning member 8 can move is set as the target of the stop position of the cleaning member 8, and the cleaning member 8 is controlled at the first stop position, and the second near the first stop position determined there is set as the target. It can also be controlled at the stop position. Thus, the more optimal the stop position can be determined as the stop position of the cleaning member 8 is taken more finely.

  Further, the determination control of the stop position of the cleaning member 8 needs to be performed after the toner sensor 7 and the cleaning members 8 and 18 are combined. However, it may be performed at the time of installing a so-called device that is first used as a developer conveying device. desirable.

  Further, the drive characteristics may change even when the cleaning members 8 and 18 are worn over the long-term use and the detection surface 7a is worn. For this purpose, the control may be started by an instruction from the user, or automatically controlled based on, for example, the number of images formed or the number of sweeps that the cleaning members 8 and 18 sweep the detection surface 7a after long-term use of the developer transport device. May be activated.

  The reference value for detection may be switched based on the peak value when the stop position or frequency band described above is determined. The output of the toner sensor 7 varies depending on individual variations of the sensor, and the load variation due to the cleaning members 8 and 18 is also large. For this reason, when the image forming apparatus is installed and no toner is present in the toner container, the peak value of the output voltage is confirmed, and when the value reaches, for example, 60% of the peak value, there is no toner. What is necessary is just to judge that it changed into the state. By doing so, it is possible to prevent the absence of toner from being detected with a too small amount of toner due to the load applied by the cleaning members 8 and 18.

  That is, on the premise of the configuration of the first embodiment, the controller 202 may set a first threshold value that is smaller than the maximum output voltage detected by the toner sensor 7. Then, the controller 202 determines a first threshold value that determines that there is no developer inside the sub toner container 1 when the output voltage of the toner sensor 7 measured by the maximum output voltage measuring unit 202A is larger than the first threshold value. A control unit may be provided. For example, the first threshold value in this case corresponds to an output voltage value of 60% of the peak value described above.

  According to this configuration, the first threshold value setting control unit determines the presence or absence of the developer in the sub toner container 1 based on the first threshold value of the toner sensor 7. From this, the user can know in advance that the state in which the developer is not present in the sub toner container 1 is approached before the state in which the developer is not present in the sub toner container 1 is reached.

  Alternatively, assuming the configuration of the second embodiment, the controller 202 sets a second threshold value that is larger than the absolute value of the minimum difference between the first frequency and the second frequency detected by the toner sensor 7. When the absolute values of the first frequency and the second frequency of the toner sensor 7 measured by the frequency measuring unit 202C are smaller than the second threshold, the controller 202 determines that there is no developer inside the sub toner container 1. You may provide the 2nd threshold value setting control part to determine.

  According to this configuration, the second threshold value setting control unit determines the presence or absence of the developer in the sub toner container 1 based on the second threshold value of the toner sensor 7. From this, the user can know in advance that the state in which the developer is not present in the sub toner container 1 is approached before the state in which the developer is not present in the sub toner container 1 is reached.

  Further, in the first and second embodiments, an example of impedance is given as an output value from the toner sensor 7. However, since the same phenomenon is observed even when the phase difference is used, control using the phase difference is performed. Also good.

  In the second embodiment, attention is paid to the point pressure generated by the cleaning member 8. However, as described in the first embodiment, a change in the peak value of the output voltage is also observed when the point pressure is applied. Further, even when a linear pressure is applied, the peak position does not shift. For this reason, when the stop position determination control described in the first embodiment and the frequency determination control described in the second embodiment are performed in combination, a more optimal remaining amount can be detected.

  In the present embodiment, the toner sensor 7 is provided in the sub-toner container 1, but the present invention is not limited to this. That is, the toner sensor 7 may be provided in the main toner container 2 or other consumables such as a process cartridge or a toner cartridge. In this case, only the position sensor 9 that detects the position of the cleaning member 8 may be provided in the image forming apparatus main body 99A.

1 Sub-toner container (developer storage container)
2 Main toner container (developer storage container)
7 Toner sensor 7a Detection surface 8, 18 Cleaning member 18b Bent tip (tip)
104 Developer transport device (Developer detection device)
201 drive mechanism 202 controller 202A output voltage measurement unit 202B first stop position control unit 202C frequency measurement unit 202D second stop position control unit

Claims (7)

A developer storage container capable of storing the developer;
A developer presence / absence detecting means attached to a wall of the developer storage container and having different driving characteristics depending on the presence or absence of the developer inside the developer storage container;
A cleaning member for cleaning while moving the surface of the developer presence / absence detecting means;
A drive mechanism for driving the cleaning member;
The developer inside the developer storage container based on the drive characteristics indicated by the developer presence / absence detection means in a state where at least a part of the cleaning member is stopped on the surface of the developer presence / absence detection means by the drive mechanism A controller for determining the presence or absence of
Have
The driving characteristic of the developer presence / absence detecting means is a characteristic of the output voltage of the developer presence / absence detecting means,
The controller is
A maximum output voltage measuring unit for measuring a maximum output voltage at which the output voltage of the developer presence / absence detection means becomes a maximum value every time the cleaning member is stopped at a plurality of stop positions on the surface of the developer presence / absence detection means;
Based on the measurement result of the maximum output voltage measuring unit, the maximum output voltage position at which the output voltage of the developer presence / absence detecting means is maximized is selected from the plurality of stop positions, and stopped at the maximum output voltage position. A first stop position controller for controlling the drive of the cleaning member,
A developer detection device comprising: The controller sets a first threshold value smaller than the maximum output voltage detected by the developer presence / absence detection unit, and the output voltage of the developer presence / absence detection unit measured by the maximum output voltage measurement unit is the first threshold value. 2. The developer detection device according to claim 1 , further comprising a first threshold value setting control unit that determines that there is no developer in the developer storage container when the value is larger than the first threshold value. A developer storage container capable of storing the developer;
A developer presence / absence detecting means attached to a wall of the developer storage container and having different driving characteristics depending on the presence or absence of the developer inside the developer storage container;
A cleaning member for cleaning while moving the surface of the developer presence / absence detecting means;
A drive mechanism for driving the cleaning member;
The developer inside the developer storage container based on the drive characteristics indicated by the developer presence / absence detection means in a state where at least a part of the cleaning member is stopped on the surface of the developer presence / absence detection means by the drive mechanism A controller for determining the presence or absence of
Have
The driving characteristic of the developer presence / absence detecting means is a frequency characteristic of the developer presence / absence detecting means,
The tip of the cleaning member is disposed so as to be able to come into contact with the surface area of the developer presence / absence detecting means,
The controller is
Each time the cleaning member is stopped at a plurality of stop positions on the surface of the developer presence / absence detection means, the first frequency corresponding to one maximum value of the output voltage of the developer presence / absence detection means and the other maximum value A frequency measurement unit for measuring the corresponding second frequency;
Based on the measurement result of the frequency measurement unit, the minimum absolute value position where the absolute value of the difference between the first frequency and the second frequency is minimized is selected from the plurality of stop positions, and the minimum absolute value position A second stop position control unit that controls the driving of the cleaning member to stop at once,
A developer detection device comprising: The controller sets a second threshold value larger than an absolute value of a minimum difference between the first frequency and the second frequency detected by the developer presence / absence detection unit, and the developer presence / absence measured by the frequency measurement unit A second threshold value setting control unit that determines that there is no developer inside the developer storage container when the absolute value of the difference between the first frequency and the second frequency of the detection unit is smaller than a second threshold value. The developer detection device according to claim 3 , further comprising: The driving characteristics, the developer detecting device according to any one of claims 1 to 4, characterized in that said an impedance characteristic of the developer presence detection means. The driving characteristics, the developer detecting device according to any one of claims 1 to 4, characterized in that a phase characteristic of the developer presence detection means. An image forming unit for forming an image;
The developer detection device according to any one of claims 1 to 6 ,
An image forming apparatus comprising:

Images