JP2022122590A - Developing device, image forming apparatus, and developer runout detection method - Google Patents

Abstract

To provide a developing device, an image forming apparatus, and a developer runout detection method that can improve accuracy in detecting runout of developer.SOLUTION: An image forming apparatus comprises: a conveying member 42 that conveys toner in a housing 41; a sensor 47 that detects the amount of toner passing through a detection position on a conveyance path of the toner conveyed by the conveying member 42; a drive processing unit that, when the amount of toner detected by the sensor 47 is equal to or less than a first reference amount, drives a supply member 46A supplying the toner from a toner container 46 to the housing 41; a detection processing unit that, when a result of detection performed by the sensor 47 does not satisfy a first specific condition from start of drive of the supply member 46A until the lapse of determination time, detects runout of developer in the toner container 46; and a switching processing unit that switches the first specific condition according to a variation value related to variation in the detection amount acquired on the basis of, the result of detection performed by the sensor 47.SELECTED DRAWING: Figure 3

Description

The present invention relates to a developing device, an image forming apparatus, and a developer depletion detection method.

2. Description of the Related Art An electrophotographic image forming apparatus includes a developing device that develops an electrostatic latent image formed on an image carrier such as a photosensitive drum. The developing device includes a first containing portion containing developer such as toner, and develops the electrostatic latent image using the developer contained in the first containing portion. Further, the developing device includes a conveying section and a sensor. The transport section transports the developer in the first container. The sensor detects the amount of the developer passing through a predetermined detection position in the developer transport path of the transport section.

In this type of developing device, when the amount of the developer detected by the sensor is equal to or less than a predetermined amount, the supply unit that supplies the developer from the second container such as a toner container to the first container is driven. be done. Further, the depletion of the developer in the second containing portion is detected based on the detection result of the sensor after the supply portion is driven (see Patent Document 1). Specifically, when it is not determined that the developer has been supplied from the second container to the first container based on the detection result of the sensor, the lack of developer is detected.

JP 2013-228619 A

By the way, when the number of times of image formation in the image forming apparatus increases, part of the developer in the first containing portion deteriorates, causing variation in fluidity of the developer in the first containing portion. As a result, the amount of developer detected by the sensor tends to fluctuate, and the detection accuracy of developer depletion decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device, an image forming apparatus, and a developer depletion detection method capable of improving detection accuracy of developer depletion.

A developing device according to one aspect of the present invention includes a first housing section, a conveying section, a sensor, a drive processing section, a detection processing section, and a switching processing section. The first accommodation portion accommodates a developer. The transport section transports the developer in the first container. The sensor detects the amount of the developer passing through a predetermined detection position in the developer transport path of the transport section. The drive processing unit moves the developer from the second storage unit storing the developer to the first storage unit when the amount of the developer detected by the sensor is equal to or less than a predetermined first reference amount. to drive the supply unit that supplies the The detection processing unit detects that the detection result of the sensor does not satisfy a preset first specific condition from the start of driving of the supply unit until a predetermined determination time elapses. , the remaining amount of the developer is equal to or less than a predetermined second reference amount, and developer depletion is detected. The switching processing unit switches the first specific condition according to a variation value relating to variation in the detected amount acquired based on the detection result of the sensor.

An image forming apparatus according to another aspect of the present invention includes the developing device and a restriction processing section. The restriction processor is capable of restricting an image forming operation when the developer shortage is detected.

A developer depletion detection method according to another aspect of the present invention includes: a first containing portion containing developer; a conveying portion for conveying the developer in the first containing portion; and a sensor that detects the amount of the developer passing through a predetermined detection position on the transport path, and includes the following drive step, detection step, and switching step. In the driving step, when the amount of the developer detected by the sensor is equal to or less than a predetermined first reference amount, the developer is transferred from the second container containing the developer to the first container. The feeder for feeding is driven. In the detection step, when the detection result of the sensor does not satisfy a preset first specific condition from the start of driving of the supply unit until a predetermined determination time elapses, Developer depletion is detected when the remaining amount of the developer is equal to or less than a predetermined second reference amount. In the switching step, the first specific condition is switched according to a variation value relating to variation in the detected amount acquired based on the detection result of the sensor.

According to the present invention, it is possible to improve the detection accuracy of developer depletion.

FIG. 1 is a block diagram showing the system configuration of an image forming apparatus according to an embodiment of the invention. FIG. 2 is a diagram showing the internal configuration of the housing of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram showing the configuration of the developing section of the image forming apparatus according to the embodiment of the invention. FIG. 4 is a diagram showing the configuration of the developing section of the image forming apparatus according to the embodiment of the invention. FIG. 5 is a flowchart showing an example of developer depletion detection processing executed by the image forming apparatus according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following embodiment is an example that embodies the present invention, and does not limit the technical scope of the present invention.

[Configuration of Image Forming Apparatus 100]
First, the configuration of an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. Here, FIG. 2 is a sectional view showing the internal configuration of the housing 6. As shown in FIG.

For convenience of explanation, the vertical direction in the installation state (the state shown in FIG. 2) in which the image forming apparatus 100 can be used is defined as the up-down direction D1. A front-rear direction D2 is defined with the right side of the image forming apparatus 100 shown in FIG. 1 as the front side. Further, the horizontal direction D3 is defined with reference to the front of the image forming apparatus 100 in the installed state.

The image forming apparatus 100 is a printer that forms an image using an electrophotographic method. Note that the image forming apparatus of the present invention may be a facsimile machine, a copier, a multifunction machine, or the like.

As shown in FIG. 1, the image forming apparatus 100 includes an image forming section 1, a paper feeding section 2, an operation display section 3, a storage section 4, and a control section 5. As shown in FIG. Further, as shown in FIG. 2 , the image forming apparatus 100 includes a housing 6 that accommodates each component of the image forming apparatus 100 .

The image forming section 1 forms an image based on image data.

The paper feeding unit 2 supplies sheets to the image forming unit 1 . As shown in FIG. 2 , the paper feeder 2 includes a paper feed cassette 31 , a first pickup roller 32 , a paper feed roller 33 , a manual feed tray 34 , a second pickup roller 35 and registration rollers 36 .

The operation display section 3 is a user interface of the image forming apparatus 100 . The operation display unit 3 includes a display unit such as a liquid crystal display for displaying various information according to control instructions from the control unit 5, and operation keys or a touch panel for inputting various information to the control unit 5 according to user operations. It has an operation part such as

The storage unit 4 is a nonvolatile storage device. For example, the storage unit 4 is a storage device such as non-volatile memory such as flash memory and EEPROM (registered trademark), SSD (Solid State Drive), or HDD (Hard Disk Drive).

The control unit 5 controls the image forming apparatus 100 as a whole. As shown in FIG. 1, the control unit 5 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 is a processor that executes various kinds of arithmetic processing. The ROM 12 is a non-volatile storage device in which information such as control programs for causing the CPU 11 to execute various processes is stored in advance. The RAM 13 is a volatile or nonvolatile storage device used as a temporary memory (work area) for various processes executed by the CPU 11 . In the control unit 5 , various control programs pre-stored in the ROM 12 are executed by the CPU 11 . Accordingly, the image forming apparatus 100 is centrally controlled by the control unit 5 .

[Configuration of Image Forming Section 1]
Next, the configuration of the image forming section 1 will be described with reference to FIGS. 1 and 2. FIG.

As shown in FIG. 2 , the image forming section 1 includes a photosensitive drum 21 , a charging device 22 , an optical scanning device 23 , a developing section 24 , a transfer roller 25 , a cleaning device 26 and a fixing device 27 . Further, as shown in FIG. 1 , the image forming section 1 includes a first driving section 28 and a second driving section 29 .

The photoreceptor drum 21 carries a toner image. The photosensitive drum 21 receives the rotational driving force supplied from the first driving section 28 and rotates in the direction of the arrow shown in FIG.

The charging device 22 charges the surface of the photosensitive drum 21 .

The optical scanning device 23 emits light based on image data toward the charged surface of the photosensitive drum 21 . Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum 21 .

The developing unit 24 develops the electrostatic latent image formed on the surface of the photosensitive drum 21 using magnetic toner. The toner is an example of the developer of the present invention. Thereby, a toner image is formed on the surface of the photosensitive drum 21 .

The transfer roller 25 transfers the toner image formed on the surface of the photosensitive drum 21 by the developing unit 24 to the sheet supplied by the paper feeding unit 2 .

The cleaning device 26 removes the toner remaining on the surface of the photosensitive drum 21 after the toner image is transferred by the transfer roller 25 .

The fixing device 27 fixes the toner image transferred onto the sheet by the transfer roller 25 onto the sheet. The sheet on which the toner image is fixed by the fixing device 27 is transferred to a paper discharge tray 39 ( 2).

The first driving unit 28 drives the photosensitive drum 21, the first conveying member 42 (see FIG. 3), the second conveying member 43 (see FIG. 3), the developing roller 44 (see FIG. 3), and the like of the developing unit 24. It is a motor that supplies rotational driving force.

The second driving section 29 is a motor that supplies rotational driving force to the toner container 46 (see FIG. 3) of the developing section 24 .

[Configuration of developing section 24]
Next, the configuration of the developing section 24 will be described with reference to FIGS. 1, 3, and 4. FIG. Here, FIG. 3 is a sectional view showing the structure of the developing section 24. As shown in FIG. 4 is a plan view showing part of the internal configuration of the housing 41. As shown in FIG.

As shown in FIG. 3 , the developing section 24 includes a housing 41 , a first conveying member 42 , a second conveying member 43 , a developing roller 44 , a regulation member 45 , a toner container 46 and a toner sensor 47 .

The housing 41 accommodates the first conveying member 42 , the second conveying member 43 , the developing roller 44 and the regulating member 45 . Further, the housing 41 accommodates a one-component developer containing the toner. The housing 41 is an example of the first housing part of the present invention.

As shown in FIGS. 3 and 4, the housing 41 includes a first transport path 51 and a second transport path 52 extending in the left-right direction D3. The second transport path 52 is provided adjacent to the first transport path 51 behind the first transport path 51 . In the first conveying path 51, the toner is conveyed in the first conveying direction D4 shown in FIG. In the second conveying path 52, the toner is conveyed in the second conveying direction D5 opposite to the first conveying direction D4.

As shown in FIG. 4 , a first communication path 53 leading to the second transport path 52 is provided at the downstream end of the first transport path 51 in the first transport direction D4. Further, as shown in FIG. 4, a second communication path 54 leading to the first transport path 51 is provided at the downstream end of the second transport path 52 in the second transport direction D5. That is, inside the housing 41, the first conveying path 51, the first communication path 53, the second conveying path 52, and the second communication path 54 form a circulation conveying path through which the toner circulates.

The first conveying member 42 is rotatably provided on the first conveying path 51 . The first conveying member 42 conveys the toner accommodated in the first conveying path 51 in the first conveying direction D4 (see FIG. 4). The first conveying member 42 is an example of the conveying section of the present invention. For example, the first conveying member 42 is a screw-shaped member that is rotatably provided on the first conveying path 51 about a rotation axis extending in the left-right direction D3. The first conveying member 42 rotates by receiving the rotational driving force supplied from the first driving section 28 . Note that the first conveying member 42 is not limited to a screw-shaped member, and may be any member capable of conveying the toner.

The second conveying member 43 is rotatably provided on the second conveying path 52 . The second conveying member 43 conveys the toner accommodated in the second conveying path 52 in the second conveying direction D5 (see FIG. 4). For example, the second conveying member 43 is a screw-shaped member that is rotatable about a rotation axis extending in the left-right direction D3 in the second conveying path 52 . The second conveying member 43 rotates by receiving the rotational driving force supplied from the first driving section 28 . The second conveying member 43 is not limited to a screw-shaped member, and may be any member capable of conveying the toner.

The developing roller 44 supplies the toner to the surface of the photosensitive drum 21 . The developing roller 44 is provided facing the photosensitive drum 21 (see FIG. 2). Further, as shown in FIG. 3, the developing roller 44 is provided facing the second conveying member 43 . The developing roller 44 is rotatably supported by the housing 41 and rotates in the direction of the arrow shown in FIG. The developing roller 44 acquires the toner from the second conveying path 52 . The toner picked up by the developing roller 44 adheres to the outer peripheral surface of the developing roller 44 due to the magnetic force of the magnetic poles provided inside the developing roller 44 . The developing roller 44 conveys the toner adhering to the outer peripheral surface to a region facing the photoreceptor drum 21 and supplies the toner to the surface of the photoreceptor drum 21 . Thereby, the electrostatic latent image formed on the photosensitive drum 21 is developed.

The regulating member 45 contacts the toner adhering to the outer peripheral surface of the developing roller 44 to triboelectrically charge the toner. As shown in FIG. 3 , the regulating member 45 is downstream of the area where the second conveying member 43 and the developing roller 44 face each other in the direction of rotation of the developing roller 44 , and is located between the developing roller 44 and the photosensitive drum 21 . is provided on the upstream side in the direction of rotation of the opposing region. The regulating member 45 is provided facing the outer peripheral surface of the developing roller 44 so that a predetermined gap is formed between the regulating member 45 and the outer peripheral surface of the developing roller 44 .

The toner container 46 accommodates the toner. The toner container 46 is an example of the second container of the invention. The toner container 46 is detachably provided in the housing 6 . The toner container 46 includes a container body, a supply port (not shown), and a supply member 46A (see FIG. 3). The container main body is elongated in the left-right direction D3 and accommodates the toner therein. The supply port is formed at the left end of the container body. The supply port is open downward. The supply port is connected to an opening (not shown) formed in the upper surface of the housing 41 . The opening opens toward the supply position P1 (see FIG. 4) in the toner transport path of the first transport member 42 on the upper surface of the housing 41 . As shown in FIG. 4 , the supply position P1 is the left end position of the first transport path 51 .

The supply member 46A supplies the toner from the toner container 46 to the supply position P1 in the housing 41 (see FIG. 4). The supply member 46A is an example of the supply section of the present invention. The supply member 46A is provided in the toner container 46 so as to be rotatable around a rotation axis extending in the left-right direction D3, and conveys the toner to the supply opening in an amount corresponding to the number of rotations. For example, the supply member 46A is a screw-shaped member capable of conveying the toner in the toner container 46 leftward. The supply member 46A rotates by receiving the rotational driving force supplied from the second driving section 29 . The toner conveyed to the supply port by the supply member 46A drops to the supply position P1 of the housing 41 via the opening. That is, the supply member 46A can supply the toner to the supply position P1 of the housing 41 in an amount corresponding to the rotation speed. Note that the supply member 46A is not limited to a screw-shaped member, and may be any member capable of transporting the toner.

The toner sensor 47 detects the amount of the toner passing through the detection position P2 (see FIG. 4) on the toner transport path of the first transport member 42 . The toner sensor 47 is an example of the sensor of the invention. As shown in FIG. 3 , the toner sensor 47 is provided on the bottom surface of the housing 41 . As shown in FIG. 4, the detection position P2 is located downstream of the supply position P1 in the first transport direction D4. For example, the toner sensor 47 is a magnetic permeability sensor that outputs a voltage corresponding to the magnetic permeability at the detection position P2. For example, the voltage output by the toner sensor 47 increases as the magnetic permeability at the detection position P2 increases. That is, the voltage increases as the amount of toner passing through the detection position P2 increases.

A voltage output by the toner sensor 47 is input to the controller 5 . Here, the voltage output by the toner sensor 47 fluctuates with the rotation period of the first conveying member 42 . The control unit 5 averages the voltage output by the toner sensor 47 over the rotation period of the first conveying member 42 . Hereinafter, the value of the output voltage of the toner sensor 47 averaged by the controller 5 over the rotation period of the first conveying member 42 is referred to as a "detection value". The detected value may be the maximum value or minimum value of the output voltage of the toner sensor 47 in the rotation period of the first conveying member 42 .

Note that the toner sensor 47 is not limited to the magnetic permeability sensor, and may be any sensor capable of detecting the amount of toner passing through the detection position P2.

[Configuration of control unit 5]
Next, the controller 5 will be described with reference to FIG.

As shown in FIG. 1 , the control section 5 includes a drive processing section 61 , a detection processing section 62 , a switching processing section 63 , a restriction processing section 64 and a release processing section 65 .

Specifically, the ROM 12 of the control unit 5 stores in advance a developer depletion detection program for causing the CPU 11 of the control unit 5 to execute developer depletion detection processing (see the flowchart of FIG. 5), which will be described later. The CPU 11 of the control unit 5 executes the developer depletion detection program stored in the ROM 12 to control the drive processing unit 61, the detection processing unit 62, the switching processing unit 63, the restriction processing unit 64, and the release processing unit. 65.

The developer depletion detection program is recorded on a computer-readable recording medium such as a CD, DVD, and flash memory. good. Moreover, the drive processing unit 61, the detection processing unit 62, the switching processing unit 63, the restriction processing unit 64, and the release processing unit 65 may be configured by an electronic circuit such as an integrated circuit (ASIC). Further, the restriction processing unit 64 may be included in a main control unit that is provided separately from the control unit 5 and that controls the image forming apparatus 100 in an integrated manner. In this case, the device including the developing section 24 and the control section 5 is an example of the developing device of the present invention.

The drive processing unit 61 drives the supply member 46A when the amount of toner detected by the toner sensor 47 is equal to or less than a predetermined first reference amount.

Specifically, the drive processing unit 61 drives the second drive unit 29 at a predetermined drive speed when the detected value is equal to or less than the first voltage value corresponding to the first reference amount. As a result, the supply member 46A is driven to supply the toner in the toner container 46 to the housing 41. As shown in FIG. Note that the first reference amount and the driving speed may be arbitrarily determined.

If the detection result of the toner sensor 47 does not satisfy a preset first specific condition from the start of driving of the supply member 46A until a predetermined determination time elapses, the detection processing unit 62 determines whether the toner container 46 Developer depletion is detected when the remaining amount of toner is equal to or less than a predetermined second reference amount.

For example, the second reference quantity is zero. Note that the second reference amount may be an amount greater than zero.

Here, the first specific condition is a condition for determining whether or not the toner supplied to the housing 41 by the supply member 46A has passed the detection position P2 (see FIG. 4). In other words, the detection processing unit 62 determines that the toner supplied to the housing 41 by the supply member 46A has passed the detection position P2 (see FIG. 4) from the start of driving of the supply member 46A to the elapse of the determination time. If not determined, the developer exhaustion is detected. The determination time is determined based on the toner transport time from the supply position P1 (see FIG. 4) to the detection position P2 (see FIG. 4) by the first transport member .

For example, the first specific condition is that the detection of the toner exceeding the third reference amount equal to or greater than the first reference amount continues beyond a first reference time shorter than the determination time. For example, the third reference amount is the same amount as the first reference amount. Also, the first reference time is 15 seconds. In this case, the detection processing unit 62 determines that the first specific condition is satisfied when the output of the detection value exceeding the first voltage value from the toner sensor 47 continues for more than 15 seconds. The third reference amount may be a larger amount than the first reference amount. Also, the first reference time may be a time different from 15 seconds.

For example, when the detection processing unit 62 detects that the developer has run out, the detection processing unit 62 stores detection information indicating the fact in a predetermined specific storage area in the RAM 13 .

By the way, when the number of times of image formation in the image forming apparatus 100 increases, part of the toner in the housing 41 deteriorates, and the fluidity of the toner in the housing 41 becomes uneven. As a result, the amount of toner detected by the toner sensor 47 tends to fluctuate, and the detection accuracy of developer depletion decreases. For example, when the supply member 46A starts to be driven when the developer is out of the developer, and the amount of toner passing through the detection position P2 (see FIG. 4) increases after the start of the drive, the supply member 46A moves the housing to 41 may be erroneously determined whether or not the toner has passed the detection position P2. If an error occurs in this determination, the detection timing of developer depletion will be delayed.

On the other hand, in the image forming apparatus 100 according to the embodiment of the present invention, it is possible to improve the detection accuracy of developer depletion, as described below. In addition, by continuously using the toner container 46 having the same amount of stored toner, the user can suppress variations in the number of printed sheets per toner container.

The switching processing unit 63 switches the first specific condition according to a variation value relating to variation in the amount of toner detected by the toner sensor 47, which is acquired based on the detection result of the toner sensor 47. FIG.

Here, the variation value is the standard deviation of the amount of toner detected by the toner sensor 47 during a predetermined acquisition period. The acquisition period is an arbitrary period longer than the rotation period of the first conveying member 42 . The variation value may be a variance of the amount of toner detected by the toner sensor 47 during the acquisition period. Further, the variation value may be the difference between the maximum value and the minimum value of the amount of toner detected by the toner sensor 47 during the acquisition period.

Specifically, when the variation value is less than a predetermined threshold value, the switching processing unit 63 sets a predetermined first detection condition as the first specific condition.

For example, the first detection condition is that the detection of the toner exceeding the third reference amount continues beyond the first reference time. The first detection condition may be that the toner sensor 47 detects the toner exceeding the third reference amount.

On the other hand, when the variation value is equal to or greater than the threshold, the switching processing unit 63 sets a second detection condition stricter than the first detection condition as the first specific condition.

For example, the second detection condition is that the detection of the toner exceeding the third reference amount continues beyond a second reference time shorter than the determination time and longer than the first reference time. For example, the second reference time is 30 seconds. In this case, when the output of the detection value exceeding the first voltage value from the toner sensor 47 continues for more than 30 seconds, it is determined that the second detection condition is satisfied. Note that the second reference time may be a time different from 30 seconds. Further, the second detection condition is that the detection of the toner exceeding the fifth reference amount, which is larger than the third reference amount, continues beyond the first reference time or the second reference time. good too. Further, the second detection condition may be that the toner sensor 47 detects the toner exceeding the fifth reference amount.

Note that the switching processing unit 63 may set, as the first specific condition, one detection condition determined according to the variation value among three or more detection conditions with different severity.

The restriction processing unit 64 can restrict the image forming operation when the developer depletion is detected.

Specifically, when the remaining amount of toner in the housing 41 becomes equal to or less than a predetermined fourth reference amount before the release processing unit 65 cancels the detection of developer depletion, the restriction processing unit 64 Restrict image forming operations.

For example, when the number of printed sheets from the detection of developer depletion reaches a predetermined reference number, the limit processing unit 64 determines that the remaining amount of toner in the housing 41 is equal to or less than the fourth reference amount. I judge that. The reference number of sheets is the difference between the amount of toner contained in the housing 41 and the fourth reference amount when the amount of toner detected by the toner sensor 47 is the first reference amount, and the number of printed sheets per sheet. It is determined based on the average value of the toner consumption. Further, the fourth reference amount is determined based on the relationship between the decrease in the amount of toner contained in the housing 41 and the print density. Specifically, the fourth reference amount is an amount equal to or larger than the amount of toner contained in the housing 41 at which the printing density starts to decrease if the fourth reference amount decreases further.

Note that the restriction processing unit 64 determines that the remaining amount of toner in the housing 41 reaches the fourth reference when the consumption of the toner after the developer depletion is detected reaches the predetermined reference consumption. It may be determined that it has become below the amount. The amount of toner consumption may be calculated based on the image data to be printed. Further, the restriction processing unit 64 may determine whether or not the amount of toner remaining in the housing 41 is equal to or less than the fourth reference amount based on the amount of toner detected by the toner sensor 47 .

Note that the restriction processing section 64 may restrict the image forming operation immediately when the developer depletion is detected.

The cancellation processing unit 65 cancels the detection of the developer shortage when the detection result of the toner sensor 47 after the detection of the developer shortage satisfies a preset second specific condition.

Here, the switching processing unit 63 switches the second specific condition according to the variation value. Specifically, when the variation value is less than the threshold, the switching processing unit 63 sets a predetermined first release condition as the second specific condition. On the other hand, when the variation value is equal to or greater than the threshold, the switching processing unit 63 sets a second release condition stricter than the first release condition as the second specific condition.

For example, the first cancellation condition is that the detection of the toner exceeding the sixth reference amount, which is equal to or greater than the first reference amount, continues beyond a predetermined third reference time. For example, the sixth reference amount is the same amount as the first reference amount. Also, the third reference time is 30 seconds. In this case, the release processing unit 65 determines that the first release condition is satisfied when the output of the detection value exceeding the first voltage value from the toner sensor 47 continues for more than 30 seconds. The sixth reference amount may be an amount larger than the first reference amount. Also, the third reference time may be a time different from 30 seconds. Further, the first cancellation condition may be that the toner sensor 47 detects the toner exceeding the sixth reference amount.

Further, the second release condition is that the detection of the toner exceeding the seventh reference amount, which is larger than the sixth reference amount, continues beyond the fourth reference time longer than the third reference time. For example, the fourth reference time is 60 seconds. In this case, the release processing unit 65 sets the second release condition when the output of the detection value exceeding the second voltage value corresponding to the seventh reference amount from the toner sensor 47 continues for more than 60 seconds. It is judged that it is sufficient. Note that the fourth reference time may be a time different from 60 seconds. Further, the second cancellation condition may be that the detection of the toner exceeding the seventh reference amount continues beyond the third reference time. Further, the second cancellation condition may be that detection of the toner exceeding the sixth reference amount continues beyond the fourth reference time. Further, the second release condition may be that the toner sensor 47 detects the toner exceeding the seventh reference amount.

Note that the switching processing unit 63 may set, as the second specific condition, one release condition determined according to the variation value among three or more release conditions with different severity.

[Developer run-out detection process]
Hereinafter, the developer depletion detection method of the present invention will be described together with an example of the developer depletion detection process executed by the control unit 5 in the image forming apparatus 100, with reference to FIG. Here, steps S11, S12, . The developer depletion detection process is executed when the image forming section 1 is driven.

<Step S11>
First, in step S11, the controller 5 determines whether or not the amount of toner detected by the toner sensor 47 is equal to or less than the first reference amount.

Specifically, when the detected value is equal to or less than the first voltage value, the controller 5 determines that the amount of toner detected by the toner sensor 47 is equal to or less than the first reference amount.

Here, the control unit 5 switches the next process according to the determination result as to whether or not the detected amount of toner is equal to or less than the first reference amount. Specifically, when the controller 5 determines that the detected amount of toner is equal to or less than the first reference amount (Yes in step S11), the process proceeds to step S12. Further, when the controller 5 determines that the detected amount of toner is not equal to or less than the first reference amount (No in step S11), it waits for the detected amount to become equal to or less than the first reference amount in step S11. .

<Step S12>
At step S12, the controller 5 drives the supply member 46A. Here, the processing of step S12 is an example of the driving step of the present invention, and is executed by the driving processing section 61 of the control section 5. FIG.

Specifically, the control unit 5 drives the second driving unit 29 at the driving speed.

<Step S13>
In step S13, the control unit 5 sets the first specific condition and the second specific condition based on the variation value. Here, the processing of step S13 is an example of the switching step of the present invention, and is executed by the switching processing section 63 of the control section 5 .

Specifically, the control unit 5 acquires the standard deviation of the detection values during the acquisition period as the variation value. Then, when the acquired variation value is less than the threshold value, the control unit 5 sets the first detection condition as the first specific condition. Moreover, the control part 5 sets the said 2nd detection conditions as said 1st specific conditions, when the said acquired variation value is more than the said threshold value. The acquisition period may be a period after or before the execution of the process of step S12, or may be a period including the execution of the process.

As a result, when part of the toner in the housing 41 is degraded and the fluidity of the toner in the housing 41 varies due to this, the detection value is lower than the first detection condition. It is determined whether or not the toner supplied to the housing 41 by the supply member 46A has passed the detection position P2 (see FIG. 4) based on the second detection condition in which the monitoring time is long. Therefore, it is possible to suppress the determination that the developer is not depleted even though the developer is depleted. Further, when there is no variation in the fluidity of the toner in the housing 41, the supply member 46A feeds the housing 41 based on the first detection condition, which is shorter than the second detection condition. It is determined whether or not the toner supplied to the body 41 has passed the detection position P2 (see FIG. 4). Therefore, even if the supply of toner from the toner container 46 to the housing 41 is intermittent due to a decrease in the remaining amount of toner in the toner container 46, it is possible to accurately determine the presence or absence of the supply.

Further, when the acquired variation value is less than the threshold value, the control unit 5 sets the first release condition as the second specific condition. Further, when the acquired variation value is equal to or greater than the threshold value, the control unit 5 sets the second release condition as the second specific condition.

As a result, when part of the toner in the housing 41 is degraded and the fluidity of the toner in the housing 41 varies due to this, the detected value It is determined whether or not the toner supplied to the housing 41 by the supply member 46A has passed the detection position P2 (see FIG. 4) based on the second release condition having a long monitoring time and a high determination reference value. be done. Therefore, it is possible to prevent cancellation of detection of developer depletion even though developer depletion is detected without error and the toner container 46 is not replaced. Further, when there is no variation in the fluidity of the toner in the housing 41, based on the first release condition having a shorter monitoring time of the detected value and a lower judgment reference value than the second release condition, , it is determined whether or not the toner supplied to the housing 41 by the supply member 46A has passed the detection position P2 (see FIG. 4). Therefore, the amount of toner supplied from the toner container 46 temporarily decreased due to the solidification of a part of the toner in the toner container 46, and as a result, it was erroneously determined that the developer had run out. In this case, it is possible to suppress difficulty in canceling the detection of developer depletion.

<Step S14>
In step S14, the control unit 5 determines whether or not the first specific condition set in step S13 is satisfied.

Here, the control unit 5 switches the next process according to the determination result as to whether or not the first specific condition is satisfied. Specifically, when the control unit 5 determines that the first specific condition is satisfied (Yes in step S14), the control unit 5 stops driving the second driving unit 29 and shifts the process to step S11. Further, when the control unit 5 determines that the first specific condition is not satisfied (No in step S14), the process proceeds to step S15.

<Step S15>
In step S15, the control unit 5 determines whether or not the determination time has elapsed since the start of execution of the process in step S12.

Here, the control unit 5 switches the next process according to the determination result as to whether or not the determination time has elapsed. Specifically, when the control unit 5 determines that the determination time has passed (Yes in step S15), the process proceeds to step S16. Further, when the control unit 5 determines that the determination time has not passed (No in step S15), the process proceeds to step S14.

<Step S16>
At step S16, the control unit 5 detects the shortage of the developer. Here, the processing of step S16 is an example of the detection step of the present invention, and is executed by the detection processing section 62 of the control section 5. FIG.

Specifically, the control unit 5 stores the detection information in the specific storage area of the RAM 13 . Note that the control unit 5 may notify the detection of developer depletion. For example, the control unit 5 may cause the operation display unit 3 to display a message that the developer has been detected and a message that prompts replacement of the toner container 46 .

<Step S17>
In step S17, the control unit 5 determines whether or not the second specific condition set in step S13 is satisfied.

Here, the control unit 5 switches the next process according to the determination result as to whether or not the second specific condition is satisfied. Specifically, when the control unit 5 determines that the second specific condition is satisfied (Yes in step S17), the process proceeds to step S20. Further, when the control unit 5 determines that the second specific condition is not satisfied (No in step S17), the process proceeds to step S18.

<Step S18>
In step S18, the controller 5 determines whether or not the remaining amount of toner in the housing 41 has become equal to or less than the fourth reference amount.

Specifically, the control unit 5 determines that the remaining amount of toner in the housing 41 has become equal to or less than the fourth reference amount when the number of printed sheets after execution of the process of step S16 reaches the reference number. do.

Here, the control unit 5 switches the next process according to the determination result as to whether or not the remaining amount of toner in the housing 41 has become equal to or less than the fourth reference amount. Specifically, when the controller 5 determines that the amount of toner remaining in the housing 41 is equal to or less than the fourth reference amount (Yes in step S18), the process proceeds to step S19. Further, when the controller 5 determines that the remaining amount of toner in the housing 41 is not equal to or less than the fourth reference amount (No side of step S18), the process proceeds to step S17.

<Step S19>
In step S19, the control unit 5 executes operation restriction processing for restricting the image forming operation. Here, the processing of step S19 is executed by the restriction processing section 64 of the control section 5. FIG.

Specifically, in the operation restriction process, the operation of the image forming section 1 is stopped. Further, in the operation restriction process, it is determined whether or not a cover member (not shown) of the housing 6 that is opened and closed when the toner container 46 is attached and detached has been opened and closed. Here, when it is determined that the cover member has been opened and closed, the second driving section 29 is driven at the driving speed. Then, when it is determined that the second specific condition is satisfied before the determination time elapses after the start of driving of the second drive unit 29, the detection of developer depletion is cancelled, and the process proceeds to step S11. is transferred to

<Step S20>
In step S20, the control section 5 cancels the detection of developer depletion. Here, the processing of step S<b>20 is executed by the release processing section 65 of the control section 5 .

Specifically, the control unit 5 deletes the detection information from the specific storage area. Further, the control unit 5 stops driving the second driving unit 29 . As a result, the amount of toner supplied from the toner container 46 temporarily decreases due to the solidification of a portion of the toner in the toner container 46, and as a result, it is erroneously determined that the developer has run out. In this case, the developer depletion detection can be canceled. Further, when the toner container 46 is replaced after the detection of developer depletion, the detection of developer depletion can be canceled without restricting the image forming operation.

Thus, in the image forming apparatus 100, the first specific condition is switched according to the variation value. As a result, it is possible to improve the detection accuracy of the developer depletion. Further, by continuously using the toner container 46 having the same amount of stored toner, the user can suppress variations in the number of printed sheets per toner container.

1 image forming unit 2 paper feeding unit 3 operation display unit 4 storage unit 5 control unit 6 housing 24 developing unit 28 first driving unit 29 second driving unit 41 housing 42 first conveying member 43 second conveying member 44 developing roller 45 regulation member 46 toner container 46A supply member 47 toner sensor 61 drive processing unit 62 detection processing unit 63 switching processing unit 64 restriction processing unit 65 release processing unit 100 image forming apparatus

Claims (7)

a first container that contains developer;
a conveying portion that conveys the developer in the first container;
a sensor that detects the amount of the developer passing through a predetermined detection position in the developer transport path of the transport unit;
a supply unit that supplies the developer from a second storage unit that stores the developer to the first storage unit when the amount of the developer detected by the sensor is equal to or less than a predetermined first reference amount; a drive processing unit that drives;
When the detection result of the sensor does not satisfy a preset first specific condition from the start of driving of the supply unit until a predetermined determination time elapses, the remaining amount of the developer in the second storage unit is detected. a detection processing unit that detects developer depletion in which the amount of developer is equal to or less than a predetermined second reference amount;
a switching processing unit that switches the first specific condition according to a variation value related to variation in the detected amount acquired based on the detection result of the sensor;
Developing device. The switching processing unit sets a predetermined first detection condition as the first specific condition when the variation value is less than a predetermined threshold, and when the variation value is greater than or equal to the threshold, the setting a second detection condition that is stricter than the first detection condition as the first specific condition;
2. The developing device according to claim 1. The first detection condition is that detection of the developer exceeding a third reference amount equal to or greater than the first reference amount continues beyond a first reference time shorter than the determination time,
The second detection condition is that the detection of the developer exceeding the third reference amount continues beyond a second reference time shorter than the determination time and longer than the first reference time.
3. The developing device according to claim 2. The variation value includes a standard deviation of the detected amount in a predetermined acquisition period,
The developing device according to any one of claims 1 to 3. a developing device according to any one of claims 1 to 4;
a restriction processing unit capable of restricting an image forming operation when the developer depletion is detected;
An image forming apparatus comprising: a cancellation processing unit that cancels the detection of developer depletion when the detection result of the sensor after the developer depletion is detected satisfies a preset second specific condition;
The restriction processing unit is configured to, when the residual amount of the developer in the first storage unit becomes equal to or less than a predetermined fourth reference amount before cancellation of detection of developer depletion by the cancellation processing unit. restrict formation movements,
The switching processing unit switches the second specific condition according to the variation value,
The image forming apparatus according to claim 5. a first containing portion containing a developer; a conveying portion for conveying the developer in the first containing portion; and the developer passing through a predetermined detection position in a conveying path of the developer by the conveying portion. A developer depletion detection method performed in a developing device comprising:
a supply unit that supplies the developer from a second storage unit that stores the developer to the first storage unit when the amount of the developer detected by the sensor is equal to or less than a predetermined first reference amount; a drive step to drive;
When the detection result of the sensor does not satisfy a preset first specific condition from the start of driving of the supply unit until a predetermined determination time elapses, the remaining amount of the developer in the second storage unit is detected. a detection step of detecting developer depletion in which the amount is equal to or less than a predetermined second reference amount;
a switching step of switching the first specific condition according to a variation value relating to variation in the detected amount acquired based on the detection result of the sensor;
A developer depletion detection method comprising:

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