JP2012093516A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of detecting an error of detection means, which detects a toner amount of a hopper unit, in an arbitrary timing even when continuously forming images.SOLUTION: An image forming device including a hopper unit 301 to which toner T is supplied from a toner bottle 300, and a CPU 500 which controls the supply of the toner T comprises: a toner detection sensor 400 having a detection surface 401 in the hopper unit 301; and a cleaning member 302 for removing the toner T adhered to the detection surface 401. The toner detection sensor 400 outputs a load existence signal by the contact of the toner T or the cleaning member 302 with the detection surface 401. When no load existence signal is output from the toner detection sensor 400 in a state where the cleaning member 302 contacts with the detection surface 401, the CPU 500 determines that an error is generated in the toner detection sensor 400.

Description

  The present invention relates to abnormality detection of a toner replenishing mechanism used in an electrophotographic type or electrostatic recording type image forming apparatus.

  In an image forming apparatus of an electrophotographic system or an electrostatic recording system, when the amount of developer in the developing device is reduced to a specified amount or less by developing an electrostatic latent image, the developer is developed from the hopper unit in which the developer is stored. A mechanism for replenishing developer is known.

The hopper unit temporarily stores the developer replenished from the toner bottle, and then can replenish an appropriate amount of developer with high fluidity by a developer replenishing screw provided in the hopper unit.
Replenishment of developer to the hopper unit is replenished from the toner bottle based on a signal from a toner detection means for detecting the remaining amount of developer in the hopper unit. As the toner detection means, there is one that uses a piezo sensor that vibrates a detection surface by a piezoelectric element on the wall surface of a hopper unit, and changes its vibration characteristics by attaching toner to the detection surface. There is also known a non-contact type toner detecting means having an LED (light emitting element) disposed on the wall surface of the hopper unit and a phototransistor (light receiving element) disposed at a position facing the LED via the hopper unit. ing. This non-contact type toner detection means can detect the remaining amount of toner from the transmittance of the toner in the hopper unit when the phototransistor receives visible light transmitted through the toner in the hopper unit from the LED. .

Further, when the piezo sensor is used, it is known that the vibration characteristics of the piezo sensor change due to the highly cohesive developer adhering to the detection surface, so that the detection surface is appropriately cleaned by a cleaning means such as a wire. It has been.
However, if these toner detection means continue to output a toner-free state due to a failure, there is a problem that the developer is excessively replenished from the toner bottle, and the developer overflows from the hopper unit, causing the image forming apparatus to become dirty. .
Therefore, in Patent Document 1, the control unit (CPU) detects a specific signal Q that is always output by the piezo sensor during a transition period from immediately after the piezo sensor is turned on until the toner can be detected, so that the piezo sensor is normal. A configuration for detecting this is disclosed.
Therefore, it is possible to detect a failure each time the piezo sensor is turned on, and to prevent the developer from overflowing from the hopper unit due to the failure and preventing the inside of the image forming apparatus from being soiled.

JP 2001-66870 A

However, in Patent Document 1, since the toner detection unit performs abnormality detection only when the power is turned on, if the toner detection unit fails during continuous image formation, the toner detection unit is then turned on. There was a problem that an abnormality could not be detected until
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of detecting an abnormality of a toner detecting unit even during continuous image formation.

  In order to solve the above problem, an image forming apparatus according to claim 1 is a toner replenishing container that contains toner for replenishment used for image formation, and a toner accumulation that accumulates toner replenished from the toner replenishing container. A cleaning member having a cleaning member for removing the toner in contact with the detection member by contacting the detection member, and a detection member that contacts the detection member Detecting means for detecting whether or not at least one of the toner and the cleaning member is in contact with the cleaning member, and the cleaning member is in contact with the detection member by the cleaning means. When it is not detected that the detection member is in contact with the detection member, the detection means causes an abnormality in the detection member. And having a determining means for determining that there.

  According to the present invention, it is possible to detect abnormality of the detection means even during continuous image formation.

Schematic sectional view of the image forming apparatus Cross-sectional view of main parts of hopper unit and toner bottle Schematic diagram of toner detection sensor Diagram showing phase characteristics of toner detection sensor Diagram showing input / output signals of toner detection sensor The figure which shows operation | movement of the cleaning member of 1st Embodiment. 1 is a control block diagram of an image forming apparatus according to a first embodiment. FIG. 3 is a flowchart illustrating processing for supplying toner to the developing device and the hopper unit according to the first embodiment. The figure which shows schematic structure of the cleaning member and cover member of 2nd Embodiment. The figure which shows operation | movement of the cleaning member and cover member of 2nd Embodiment. The flowchart figure showing the process which supplies a toner to the hopper unit of 2nd Embodiment.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a tandem type full-color image forming apparatus. In the image forming apparatus of the present embodiment, an image reading unit 1R optically reads a document image and transmits it as an electrical signal to the image output unit 1P.
Each of the four image forming units 10a to 10d has photosensitive drums 11a to 11d as image carriers, around which chargers 12a to 12d, exposure devices 13a to 13d, developing units 14a to 14d, and primary transfer units. 35a-35d and drum cleaners 15a-15d are disposed. In a full-color image forming apparatus, the image forming unit 10a forms a black toner image, the image forming unit 10b forms cyan, the image forming unit 10c forms magenta, and the image forming unit 10d forms a yellow toner image, which are sequentially superimposed on the intermediate transfer belt 31. Transfer to form a full-color toner image.

Next, an image forming operation will be described.
The surfaces of the photosensitive drums 11a to 11d are uniformly charged by the chargers 12a to 12d. Next, when the exposure devices 13a to 13d expose the photosensitive drums 11a to 11d via the mirrors 16a to 16d with the laser beams a to d modulated according to the image signal output from the image reading unit 1R, the photosensitive drum 11a. ˜11d forms an electrostatic latent image on its surface.

  Next, the electrostatic latent images are visualized by the toners of the developing units 14a to 14d, and the photosensitive drums 11a to 11d carry toner images corresponding to the respective colors. When the toner images enter the primary transfer portions Ta to Td by the rotation of the photosensitive drums 11a to 11d, the toner images are sequentially superimposed and transferred onto the intermediate transfer belt 31 by the transfer voltages from the primary transfer portions 35a to 35d. On 31, a full-color toner image is formed. Thereafter, the toner remaining on the photosensitive drums 11a to 11d without being transferred to the intermediate transfer belt 31 in the primary transfer portions Ta to Td is removed by the drum cleaners 15a to 15d.

The intermediate transfer belt 31 is stretched around a drive roller 32, a driven roller 33, and a secondary transfer counter roller 34, and is driven to rotate in the direction of arrow B in the figure.
The driving roller 32 is rotationally driven by a pulse motor or a brushless DC motor as driving means (not shown).
The toner image carried on the intermediate transfer belt 31 is rotated by the intermediate transfer belt 31 and the secondary transfer counter roller 34 presses the secondary transfer roller 36 via the intermediate transfer belt 31. It is conveyed to. At this time, the recording material P in the paper feed cassette 21 passes through the paper feed guide 24 by the pick-up roller 22 and the transport roller 23, the paper position and the feed timing are adjusted by the registration roller 25, and come into contact with the toner image. The toner is discharged to the secondary transfer portion Te.
When the toner image on the intermediate transfer belt 31 and the recording material P sent out from the registration roller 25 enter the secondary transfer portion Te, the secondary transfer roller 36 and the secondary transfer counter roller 34 are driven by a voltage power source (not shown). A transfer electric field is formed between the two. As a result, the toner image on the intermediate transfer belt 31 is transferred to the recording material P. The toner remaining on the intermediate transfer belt 31 without being transferred to the recording material P (FIG. 2) is removed by the belt cleaner 50.

The recording material P carrying the toner image is conveyed to the fixing unit 40 by the paper discharge guide 43. In the fixing unit 40, the fixing roller pair 41a, 41b sandwiches and conveys the toner image and the recording material P, and heats the toner image onto the recording material P by heating with a heater (not shown) provided in the fixing roller 41a. And become established.
Thereafter, the recording material P on which the toner image is fixed is discharged to a discharge tray 47 by an inner discharge roller 44 and an outer discharge roller 46.

Next, with reference to FIG. 2, a hopper unit 301 serving as a toner accumulating unit that is provided for each of the developing units 14a to 14d and temporarily accumulates toner T of each color supplied to the developing units 14a to 14d will be described. .
FIG. 2 shows one of the developing units 14a to 14d (developing unit 14) of FIG. 1, a hopper unit 301 for accumulating replenishing toner T provided in the developing unit 14, and a hopper unit 301. 3 is a schematic cross-sectional view of a toner bottle 300 as a toner supply container. When the toner T in the developing device 14 decreases, the replenishment toner T used for image formation from the toner bottle 300 is replenished via the hopper unit 301.

The toner bottle 300 contains toner T for replenishment to the hopper unit 301, and a spiral guide groove for conveying the toner T is formed on the inner surface thereof. When the toner bottle 300 is driven to rotate, the toner T in the toner bottle 300 is supplied to the hopper unit 301 from the opening.
The hopper unit 301 has a toner detection sensor 400 as toner detection means for detecting the presence or absence of toner T in the hopper unit 301. Details of the toner detection sensor 400 will be described later. The hopper unit 301 further includes a cleaning member 302 that cleans the toner detection sensor 400, and a replenishment screw 303 that serves as a replenishment unit that replenishes the developer 14 with replenishment toner T.
The replenishing screw 303 can rotate a predetermined time to replenish an arbitrary amount of toner T from the hopper unit 301 to the developing device 14. Further, a supply screw rotation detection sensor 304 (FIG. 7) for detecting the rotation time of the supply screw 303 is connected in the vicinity of the supply screw 303.

The developing unit 14 is provided with an inductive sensor 501 as toner amount detecting means for detecting the toner amount in the developing unit. The inductive sensor 501 detects the ratio (toner amount) of the toner to the carrier in the developer by detecting the magnetic permeability of the developer (carrier and toner T) in the developing device 14. In the developing device 14 of this embodiment, the absolute value of the difference between the magnetic permeability μ of the developer in the developing device 14 and the reference magnetic permeability μ _norm stored in advance in the ROM 510 (FIG. 7) is equal to or less than the threshold value t ( If it is Formula 1, the toner amount is appropriate.
| Μ _norm −μ | ≦ t (where μ _norm > t) (Expression 1)
Further, the toner amount detecting means is not limited to this configuration. For example, reflected light that irradiates light onto a measurement toner image transferred onto the intermediate transfer belt 31 and receives the reflected light by a photoelectric element. A sensor may be used. With this configuration, the ratio of the toner to the carrier (toner amount) in the developer is reduced by the amount of reflected light from the measurement toner image being out of the predetermined threshold range. Can be detected.

FIG. 3 is a schematic configuration diagram of a powder level sensor used as the toner detection sensor 400 in the present embodiment. The powder level sensor used in the present invention is a separately excited oscillation type powder level sensor, and TSP1510C-01 (manufactured by TDK) was used. Detailed explanation of the measurement principle of the powder level sensor used in this embodiment is omitted.
The powder level sensor 400 includes a detection unit 410 and a control unit 420.
The detection unit 410 has a configuration in which a piezoelectric ceramic 402 is sandwiched between a detection surface 401 as a detection member that contacts the toner T in the hopper unit 301 and an electrode 403. Note that the detection unit 410 of the present embodiment has a natural frequency of 6.7 kHz.
The control unit 420 includes an oscillator device 404, phase detection units 405 and 406, and a phase comparison unit 407, and is connected to the detection surface 401 and the electrode 403, respectively.

The oscillator device 404 vibrates the detection unit 410 by applying an AC voltage to the piezoelectric ceramic 402 through the detection surface 401 and the electrode 403. In the present embodiment, the oscillator device 404 takes 20 [ms] as one cycle, and changes the detection unit 410 stepwise at a frequency (4 [kHz] to 8 [kHz]) in the vicinity of the natural frequency during one cycle. AC voltage is applied.
The phase detection unit 405 detects a signal indicating the vibration state of the detection surface 401, and the phase detection unit 406 detects a signal indicating the vibration state of the electrode 403.
The phase comparison unit 407 counts the resonance point presence / absence signal based on the vibration state of the detection surface 401 detected by the phase detection unit 405 and the vibration state of the electrode 403 detected by the phase detection unit 406.

Here, the vibration state of the detection unit 410 will be described before the resonance point presence / absence signal is described.
FIG. 4 shows data indicating the vibration state of the detection unit 410 during one cycle. FIG. 4A shows a vibration state of the detection unit 410 when the toner T is not attached to the detection surface 401 provided on the wall surface of the hopper unit 301 and the cleaning member 302 is not in contact with the detection surface 401. It is a signal which shows. A significant resonance point A appears when the detection unit 410 vibrates at its natural frequency. FIG. 4B shows the vibration state of the detection unit 410 when the toner T adheres to the detection surface 401 provided on the wall surface of the hopper unit 301 or when the cleaning member 302 is in contact with the detection surface 401. It is a signal to show. Even when the detection unit 410 vibrates at its natural frequency, a significant resonance point A does not appear.

  Here, the remarkable resonance point A means that the phase difference between the vibration state of the detection surface 401 output from the phase detection unit 405 and the vibration state of the electrode 403 output from the phase detection unit 406 is a predetermined phase in the vicinity of the natural frequency. It means that it rises larger than (0 [deg] in this embodiment). The predetermined phase of the present embodiment includes a signal indicating a vibration state when the cleaning member 302 is brought into contact with the detection surface 401 where no toner is attached, and when the toner and the cleaning member 302 are not in contact with the detection surface. It is a value determined by comparing signals indicating the vibration state of

When a significant resonance point A appears as shown in FIG. 4A, the phase comparison unit 407 counts as a resonance point presence / absence signal at a low level (0 [V] in this embodiment). Further, the phase comparison unit 407 counts the resonance point presence / absence signal at a high level (5 [V] in the present embodiment) unless a significant resonance point A appears as shown in FIG.
FIG. 5 is a diagram showing a resonance point presence / absence signal (FIG. 5A) counted by the phase comparison unit 407 and a load signal (FIG. 5B) output from the phase comparison unit 407 to the CPU 500 (FIG. 7). It is. The horizontal axis of FIG. 5 is time, and in this embodiment, one scale is one period (20 [ms]). The vertical axis in FIG. 5 is the output voltage.

  The phase comparison unit 407 outputs a high level (5 [V] in this embodiment) signal to the CPU 500 when the high level resonance point presence / absence signal continues for a predetermined number of times or more. In this embodiment, the signal of 0 [V]) is continuously output to the CPU 500. In the present embodiment, a high level (5 [V]) signal output from the phase comparison unit 407 is a loaded signal, and a low level (0 [V]) signal is a no-load signal.

  More specifically, the phase comparison unit 407 detects the vibration state of the detection unit 410 from the signal output from the phase detection unit 405 and the signal output from the phase detection unit 406 every cycle (20 [ms]). Is detected, and a high-level (5 [V]) resonance point presence / absence signal is counted. The phase comparison unit 407 starts outputting a signal with load (5 [V]) after the high-level (5 [V]) resonance point presence / absence signal continues for a predetermined number of times (10 times in the present embodiment) or more. That is, the phase comparison unit 407 has a predetermined time or longer (200 [ms] or longer in this embodiment) if the toner T adheres to the detection surface 401 or if the cleaning member 302 is in contact with the detection surface 401. Start to output a signal with load (5 [V]).

Further, the phase comparison unit 407 continues to output a no-load signal (0 [V]) until a high-level (5 [V]) resonance point presence / absence signal is continuously detected a predetermined number of times (10 times) or more. The phase comparison unit 407 resets the count when the power of the powder level sensor (toner detection sensor 400) is turned on.
In other words, the phase comparison unit 407 is provided in order to reduce detection errors due to variations in signals indicating the vibration state input from the phase detection units 405 and 406 and to increase detection accuracy.

  FIG. 6 is a schematic view of a main part when the detection surface 401 of the powder level sensor 400 is viewed from inside the hopper unit 301, and the detection surface 401 provided on the wall surface of the hopper unit 301 by using the cleaning member 302 is shown. The cleaning operation will be described.

As the cleaning member 302, SUS, plated iron wire, or blade-like elastic rubber is used.
The cleaning member 302 is controlled by the mechanical mechanism and the cleaning drive unit 306 (FIG. 7) to stop at a position where it does not contact the detection surface 401 (FIG. 6A or FIG. 6C). The cleaning member 302 of this embodiment continues to slide on the detection surface 401 in the order of (a) → (b) → (c) → (b) → (a) →. ing. As a result, the cleaning member 302 causes the toner adhering to the detection surface 401 when the toner T in the hopper unit 301 is stirred by a stirring roller (not shown) or when the toner T is supplied from the toner bottle 300 to the hopper unit 301. T is removed.

Next, the abnormality detection process of the toner detection sensor 400 will be described with reference to FIGS.
FIG. 7 is a control block diagram of the image forming apparatus. FIG. 8 is a flowchart showing a process of supplying the toner T to the developing device 14 or the hopper unit 301 and includes an abnormality detection process of the toner detection sensor 400.

The CPU 500 is a control circuit that controls the entire image forming apparatus. The ROM 510 stores a control program for controlling various processes executed by the image forming apparatus. The RAM 520 is a system work memory for the CPU 500 to operate. A program for executing the flowchart of FIG. 8 is stored in the ROM 510 and is executed by being read by the CPU 500.
When a signal instructing the replenishment of toner from the CPU 500 to the hopper unit 301 is input from the CPU 500, the toner bottle driving unit 305 rotates the toner bottle 300 to replenish the toner T in the toner bottle 300 to the hopper unit 301. Further, the toner bottle driving unit 305 performs an opening / closing operation of an opening through which the toner T in the toner bottle 300 is discharged to the hopper unit 301 in accordance with an opening / closing signal from the CPU 500.

In accordance with a signal from the CPU 500, the cleaning driving unit 306 switches the cleaning member 302 from (a) to (b) to (c) to (b) in FIG. 6 by switching between normal rotation and reverse rotation of a pulse motor or a brushless DC motor. It is made to slide in the order of (a) →. The cleaning driving unit 306 according to the present embodiment drives the cleaning member 302 at the first speed V _norm and the second speed V _slow in response to a signal from the CPU 500. Here, the first speed V _norm means that the cleaning member 302 contacts the detection surface 401 for a time shorter than a predetermined time while sliding once from the position of FIG. _6A to the position of FIG. 6C. Speed. Further, the second speed V _slow is a speed at which the cleaning member 302 contacts the detection surface for a predetermined time or more while sliding once from the position of FIG. 6A to the position of FIG.

  The supply screw drive unit 307 is a brushless DC motor, and rotates the supply screw 303 by a signal from the CPU 500. The supply screw rotation detection sensor 304 is a sensor that measures the rotation time of the supply screw 303. Note that the amount of toner to be replenished to the developing device 14 by rotating the replenishment screw 303 for 1 second is determined in advance.

In the toner detection sensor 400, the cleaning member 302 is in contact with the detection surface 401 when the toner T adheres to the detection surface 401 for a predetermined time (200 [ms] in this embodiment) or more. As a result, a signal with load (5 [V]) is output.
The display unit 2 as a display unit is a display provided in the main body of the image forming apparatus illustrated in FIG. 1, and the CPU 500 is also an abnormality notification unit that outputs a signal to notify the abnormality to the display unit 2. In the present embodiment, the user is notified of an abnormality of the image forming apparatus by a signal from the CPU 500. The display unit 2 may be a PC display connected to the image forming apparatus through a network.

When the magnetic permeability μ of the developer in the developing device 14 detected by the inductive sensor 501 becomes larger than μ _norm + t (that is, the ratio of the toner in the developer is insufficient), the CPU 500 shows in the flowchart of FIG. Execute control. Hereinafter, μ _norm + t is referred to as μ _max . Note that t represents an allowable error with respect to the target reference magnetic permeability μ _norm , and μ _max corresponds to the maximum value in a proper magnetic permeability range.

  Alternatively, the control shown in the flowchart of FIG. 8 may be executed after the developing unit 14 has developed the photosensitive drum 11 a predetermined number of times, or after the main power supply of the image forming apparatus is turned on, the flowchart of FIG. The control shown may be executed.

Next, processing for supplying the toner T to the developing device 14 or the hopper unit 301 will be described based on a flowchart shown in FIG. The process of this flowchart is executed when the CPU 500 reads out a program stored in the ROM 510.
When starting to supply toner T to the developing device 14 or the hopper unit 301, the CPU 500 drives the cleaning member 302 at the first speed _Vnorm by the cleaning driving unit 306, and slides the detection surface 401 (S800).

The first speed V _norm of the present embodiment is a speed at which the time required for the cleaning member 302 to slide once from the position of FIG. 6A to the position of FIG. 6C is 160 [ms]. is there. Therefore, if no toner is attached to the detection surface 401, the high-level (5 [V]) resonance point presence / absence signal detected by the phase comparison unit 407 continues for less than a predetermined number of times. Therefore, the signal output from the phase comparison unit 407 to the CPU 500 is a no-load signal (0 [V]).

Further, the first speed V _norm is not limited to the speed of the present embodiment, and the phase comparison unit 407 outputs a resonance point presence / absence signal of a high level (5 [V]) continuously for a predetermined number of times (10 times). Any speed may be used as long as the speed is not detected.
Next, the CPU 500 determines whether or not the signal output from the toner detection sensor 400 is a loaded signal (5 [V]) (S801). While the cleaning member 302 is driven at the first speed V _norm , the resonance point presence / absence signal detected by the phase comparison unit 407 is a high level (5 [V]) unless the detection surface 401 is covered with the toner T. ) Signal does not become a continuous signal for a predetermined number of times (10 times).

In step S801, when the signal output from the toner detection sensor 400 is a loaded signal (5 [V]), the CPU 500 causes the inductive sensor 501 to set the toner amount of the developing device 14 to the minimum value within the proper toner amount range. It is determined whether or not this is the case (S802). Specifically, the CPU 500 determines whether the magnetic permeability μ of the developer of the developing device 14 measured by the inductive sensor 501 is equal to or lower than a predetermined magnetic permeability μ _max . If the magnetic permeability μ of the developing device 14 is equal to or less than a predetermined magnetic permeability μ _max , the amount of toner in the developer of the developing device 14 is equal to or greater than the minimum value in the appropriate toner amount range.

If the magnetic permeability μ of the developer in the developing device 14 is equal to or smaller than the predetermined magnetic permeability μ _{max in} step S802, the CPU 500 stops driving the cleaning member 302 by the cleaning drive unit 306 (S803). As a result, the abnormality detection process of the toner detection sensor 400 ends together with the process of supplying the toner T to the developing device 14 or the hopper unit 301.

Next, a case where the CPU 500 determines that the signal output from the toner detection sensor 400 is a no-load signal (0 [V]) in step S801 will be described.
When the no load signal (0 [V]) is output from the toner detection sensor 400 in step S801, the CPU 500 causes the cleaning drive unit 306 to drive the cleaning member 302 at the second speed _Vslow to slide the detection surface 401. (S804).

The second speed V _slow of the present embodiment is a speed at which the time required for the cleaning member 302 to slide once from the position of FIG. 6A to the position of FIG. 6C is 300 [ms]. is there. Therefore, the high level (5 [V]) resonance point presence / absence signal detected by the phase comparison unit 407 continues for a predetermined number of times (10 times), and the signal output from the phase comparison unit 407 to the CPU 500 is a signal with a load ( 5 [V]).

Here, the second speed _Vslow is not limited to the configuration of the present embodiment, and the phase comparison unit 407 continuously outputs a high-level (5 [V]) resonance point presence / absence signal a predetermined number of times (10 times) or more. The detection speed may be used.
Further, the second speed _Vslow is not limited to the speed of the present embodiment, and the resonance point presence / absence signal of the high level (5 [V]) is continuously supplied to the phase comparison unit 407 for a predetermined number (10 times) or more. Any speed may be used as long as the speed is detected.

As described above, the CPU 500 selects whether to drive the cleaning member 302 at the first speed V _norm or at the second speed V _{slow according} to the detection result of step 801.

Next, in order to determine whether the toner detection sensor 400 is normal, the CPU 500 receives a load signal (5 [V]) from the toner detection sensor 400 by the cleaning member 302 sliding on the detection surface 401 at the second speed. ) Is output (S805). At this time, if the toner detection sensor 400 is normal, the toner T adhering to the detection surface 401 should be removed by driving the cleaning member 302 at the first speed _Vnorm .

  In step S <b> 805, if the load signal (5 [V]) is output from the toner detection sensor 400, the CPU 500 determines that the toner detection sensor 400 is normal and detects that the toner T is insufficient in the hopper unit 301. To do.

  Next, the CPU 500 replenishes the toner T from the toner bottle 300 to the hopper unit 301 by driving the toner bottle driving unit 305 for a predetermined time (2 [s] in this embodiment) (S806), and proceeds to step S800. By repeating Step S800 to Step S806, the toner T is supplied to the hopper unit 301 from the toner bottle 300 until the detection surface 401 is covered with the toner T.

  On the other hand, when the no load signal (0 [V]) is output from the toner detection sensor 400 in step S805, the CPU 500 prohibits the replenishment of the toner T from the toner bottle 300 to the hopper unit 301 (S807). This is because a failure (abnormality 1) in which the output of the toner detection sensor 400 is always 0 [V] has occurred. In the present embodiment, if the signal output from the toner detection sensor 400 is 0 [V] (no load signal), the CPU 500 determines that the toner T of the hopper unit 301 is decreasing, and from the toner bottle 300. The toner T is continuously supplied to the hopper unit 301. That is, if the CPU 500 cannot determine that the abnormality 1 has occurred, the toner will overflow from the hopper unit 301 due to excessive supply of toner to the hopper unit 301, and the inside of the image forming apparatus may be soiled. End up. For this reason, if no load signal (5 [V]) is output in step S807, the toner T is prohibited from being replenished to prevent the toner from overflowing from the hopper unit 301.

In step S <b> 807, the CPU 500 may prohibit the output of a signal instructing supply of toner to be output to the toner bottle driving unit 305. Alternatively, the opening of the toner bottle 300 may be sealed by the open / close signal output from the CPU 500 to prohibit the replenishment of the toner T.
In step S807, when the abnormality 1 has occurred, the CPU 500 prohibits the replenishment of the toner T from the toner bottle 300 to the hopper unit 301, but further prohibits the execution of the image forming operation. Also good. Alternatively, the image forming operation may be prohibited after an image forming operation is executed for a predetermined number of sheets recorded in advance in the ROM 510 after the occurrence of abnormality 1 is detected.

Further, after step S807, the CPU 500 serving as the abnormality notification unit may output a signal for notifying the display unit 2 that abnormality 1 has occurred in the toner detection sensor 400.
In steps S804 and S805, the CPU 500 drives the cleaning member 302 at the second speed _Vslow , and the toner detection sensor 400 generates a load signal (5 [V]) due to contact with the detection surface 401 of the cleaning member 302. Judge whether to output. As a result, the CPU 500 determines that the 0 [V] signal output from the toner detection sensor 400 is due to a failure of the toner detection sensor 400 or that the toner T in the hopper unit 301 is insufficient. 0 [V]) is identified.

Next, in step S802, the CPU 500 determines that the magnetic permeability μ in the developer of the developing device 14 measured by the inductive sensor 501 is larger than a predetermined magnetic permeability μ _max (that is, the amount of toner in the developer is lower than the target value). The case where it is less than a predetermined amount) will be described. Here, the target value is the amount of toner in the developing device 14 when the magnetic permeability μ of the developer in the developing device 14 is the reference magnetic permeability μ _norm .

The CPU 500 uses the first table representing the correspondence between the magnetic permeability μ measured by the inductive sensor 501 and the magnetic permeability stored in the ROM 510 and the insufficient amount of toner, and thus the insufficient amount of toner in the developing device 14. The amount is calculated (S808). Here, the insufficient amount of toner is the amount of toner necessary for the magnetic permeability μ of the developer in the developing device 14 to become the reference magnetic permeability μ _norm when the toner is supplied into the developing device 14. .

  That is, when the replenishment screw 303 replenishes the shortage amount of toner from the hopper unit 301 to the developing device 14, even if an error occurs in the replenishment amount of the replenishment screw 303, the toner amount in the developing device 14 is the appropriate toner. It is configured to be surely replenished until the amount is reached.

  Next, the CPU 500 causes the replenishment screw drive unit 307 to rotate the replenishment screw 303 for the rotation time of the replenishment screw 303 necessary for replenishing the insufficient amount of toner calculated in step S808 (S809). Here, the insufficient toner amount and the rotation speed of the replenishing screw 303 are also obtained from the second table representing the correspondence between the toner amount stored in the ROM 510 and the rotation time.

  Here, the hopper unit 301 of the present embodiment has the detection surface 401 disposed at a position where the capacity of the toner T accumulated so as to cover the detection surface 401 becomes equal to or greater than the capacity of the toner T that can be accommodated in the developing device 14. ing. For this reason, the toner T in the hopper unit 301 is not emptied while the toner T is being supplied from the hopper unit 301 to the developing device 14.

In steps S808 and S809, the CPU 500 completes the replenishment of toner from the hopper unit 301 into the developing device 14 by the replenishment screw drive unit 307.
Next, the CPU 500 determines again whether or not the toner amount of the developing device 14 is equal to or larger than the minimum value of the appropriate toner amount range by the inductor sensor 501 (S810). Specifically, the CPU 500 determines whether the magnetic permeability μ of the developer of the developing device 14 measured by the inductive sensor 501 is equal to or lower than a predetermined magnetic permeability μ _max .

In step S810, CPU 500, if the magnetic permeability mu is equal to or less than a predetermined magnetic permeability mu _max as measured by Indakusensa 501, the toner amount in the developing device 14 is determined to be in the range of proper amount of toner to step S800 And migrate.

On the other hand, if the magnetic permeability μ of the developer of the developing device 14 measured by the inductive sensor 501 is larger than the predetermined magnetic permeability μ _max even after the toner T is supplied to the developing device 14 in step S809, the CPU 500 performs the image forming operation. Is prohibited (S811). In step S811, the CPU 500 determines that the amount of toner in the developer is smaller than the target value by a predetermined amount or more if the magnetic permeability μ of the developer is larger than the predetermined permeability μ _max .

  In step S810, if the developer in the developing device 14 that has supplied the insufficient amount of toner does not fall within the proper toner amount range, the hopper unit 301 has not accumulated toner T enough to cover the detection surface 401. become. That is, the toner detection sensor 400 continues to output a high level (5 [V]) signal, or a 5 [V] signal is output when the cleaning member 302 is stopped in contact with the detection surface 401. A failure that continues (abnormality 2) has occurred.

  In the present embodiment, if the signal output from the toner detection sensor 400 is 5 [V] (a signal with load), the CPU 500 determines that the toner T is sufficiently accumulated in the hopper unit 301 and the toner bottle. The toner is not supplied from 300 to the hopper unit 301. That is, if the CPU 500 cannot determine that the abnormality 2 has occurred, the toner amount replenished from the hopper unit 301 to the developing device 14 will be smaller than the toner amount that should be replenished. As a result, the amount of toner in the developer of the developing device 14 is not sufficient, and an image defect such as a decrease in the image density of the output product occurs.

  In this embodiment, the execution of the image forming operation is prohibited in step S811. However, after step S811, the CPU 500 serving as the abnormality notification unit notifies the display unit 2 that abnormality 2 has occurred in the toner detection sensor 400. It is good also as a structure which outputs the signal for alerting | reporting.

In the present embodiment, in step S <b> 801, the CPU 500 determines whether or not the toner T is attached to the detection surface 401 while the cleaning member 302 is slid at the first speed V _norm by the cleaning driving unit 306. Deciding. Further, in step S805, the CPU 500 determines whether or not the cleaning member 302 is in contact with the detection surface 401 while the cleaning drive unit 306 slides the cleaning member 302 at the second speed _Vslow. ing.

  Therefore, the CPU 500 may be configured to stop the cleaning member 302 at a position where it does not come into contact with the detection surface 401 (FIG. 6A or FIG. 6C) by the cleaning drive unit 306 before performing the determination in step S801. . With this configuration, if the toner detection sensor 400 is normal in step S801, the toner detection sensor 400 outputs a load presence signal (5 [V]) only when the detection surface 401 is covered with the toner T. .

  Further, the CPU 500 may be configured to stop the cleaning member 302 at a position in contact with the detection surface 401 for a predetermined time (200 [ms]) or longer by the cleaning driving unit 306 before performing the determination in step S805. With this configuration, if the toner detection sensor 400 is normal in step S805, the toner detection sensor 400 outputs a load signal (5 [V]) only when the cleaning member 302 is in contact with the detection surface 401. To do.

  As described above, if the cleaning member 302 is stopped at an arbitrary position only in step S801 or step S805 by the cleaning driving unit 306, the moving speed of the cleaning member 302 can be made constant. Thereby, the failure of the toner detection sensor 400 can be easily detected.

(Second Embodiment)
Since the basic configuration of the present embodiment is the same as that of the first embodiment, the same or substantially the same components as those of the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted. A characteristic part will be described.

FIG. 9A is a schematic view of a main part of the cleaning member 302 and the cover member 308 when the detection surface 401 is viewed from the hopper unit 301 of the present embodiment. FIG. 9B is a cross-sectional view taken along the line AA ′ of FIG.
The cleaning member 302 of this embodiment is integrated with a cover member 308 that covers the detection surface 401. The cover member 308 removes the toner T attached to the detection surface 401 by the cleaning member 302 and covers the detection surface 401 in a sealed state even after the cleaning member 302 is separated from the detection surface 401, so that the toner T adheres to the detection surface 401. It is the structure which prevents doing.

  FIG. 10 is a schematic diagram (FIG. 10A) when driving of the cleaning member 302 and the cover member 308 according to the present embodiment is viewed from inside the hopper unit 301, and is output from the normal toner detection sensor 400 to the CPU 500. It is a load signal (FIG. 10 (B), FIG.10 (C)). In FIG. 10B and FIG. 10C, the horizontal axis is time, and the vertical axis is voltage.

  In accordance with a signal from the CPU 500, the cleaning drive unit 306 of the present embodiment moves the cleaning member 302 from the position (a) in FIG. 10A by switching between forward rotation and reverse rotation of the pulse motor and the brushless DC motor (c). ) Is reciprocated between the positions. While the cleaning member 302 is slid once from the position (a) in FIG. 10A to the position (c), the time during which the cleaning member 302 is in contact with the detection surface 401 is 300 [ms]. Drive at speed. This is because, while the cleaning member 302 slides once on the detection surface 401, the toner detection sensor 400 detects the cleaning member 302 in contact with the detection surface 401 and outputs a signal with load (5 [V]). Speed. Further, the speed at which the cleaning member 302 is driven is not limited to the speed of the present embodiment, and a high-level (5 [V]) resonance point presence / absence signal detected by the phase comparison unit 407 of the toner detection sensor 400. May be a speed that continues for a predetermined number of times (10 times) or more.

  FIG. 10B shows the cleaning member 302 and the cover member 308 in the state where the toner T in the hopper unit 301 adheres to the detection surface 401 (a) → (b) → (c ) Is a signal output from the toner detection sensor 400 when driven in this order.

  When the cleaning member 302 and the cover member 308 are separated from the detection surface 401 ((a) in FIG. 10A), since the toner T is in contact with the detection surface 401, the toner detection sensor 400 outputs the toner T. The signal is a loaded signal (5 [V]). Hereinafter, the positions of the cleaning member 302 and the cover member 308 in which the relationship between the detection surface 401, the cleaning member 302, and the cover member 308 is (a) in FIG.

  Next, when the cleaning member 302 slides on the detection surface 401 and reaches the position shown in FIG. 10A, the toner detection sensor 400 loads the toner T and the cleaning member 302 by contacting the detection surface 401 with the load. A presence signal (5 [V]) is output. Thereafter, the movement that causes the toner detection sensor 400 to output a signal with load (5 [V]) when the cleaning member 302 slides on the detection surface 401 is referred to as a contact movement.

  Next, the toner T adhering to the detection surface 401 is removed by the cleaning movement of the cleaning member 302. After that, when the cover member 308 comes to a position covering the detection surface 401 ((c) in FIG. 10A), the detection surface 401 is covered with the cover member 308 and is isolated from the toner T in the hopper unit 301. The Accordingly, the toner detection sensor 400 outputs a no-load signal (0 [V]). Hereinafter, the relationship between the detection surface 401, the cleaning member 302, and the cover member 308 is (c) in FIG.

On the other hand, FIG. 10C shows the cleaning member 302 and the cover member 308 in the state where the toner T in the hopper unit 301 is not attached to the detection surface 401 (a) → (b) → It is a signal output from the toner detection sensor 400 when driven in the order of (c).
When the cleaning member 302 and the cover member 308 are at the initial positions ((a) in FIG. 10A), the toner T in the hopper unit 301 is not attached to the detection surface 401, and therefore output from the toner detection sensor 400. The signal to be output is a no-load signal (0 [V]).

Next, when the cleaning member 302 and the cover member 308 come into contact with each other and come to the position (b) of FIG. 10A, the toner detection sensor 400 is loaded by the cleaning member 302 coming into contact with the detection surface 401. A signal (5 [V]) is output.
Next, when the cleaning member 302 and the cover member 308 come to the toner isolation position ((c) in FIG. 10A), the toner detection sensor 400 is not loaded again by the cleaning member 302 being separated from the detection surface 401. A signal (0 [V]) is output.

  Next, abnormality detection processing of the toner detection sensor 400 in the present embodiment will be described with reference to a flowchart representing processing for supplying toner T to the hopper unit 301 in FIG.

  When the CPU 500 starts to supply the toner T to the hopper unit 301, the cleaning drive unit 306 causes the cleaning member 302 to contact and move (S900).

  Next, the CPU 500 determines whether or not the signal output from the toner detection sensor 400 during the contact movement of the cleaning member 302 is a loaded signal (5 [V]) (S901). If there is no abnormality in the toner detection sensor 400, the load signal (5 [V]) should be output because the cleaning member 302 is in contact with the detection surface 401 during the contact movement of the cleaning member 302. .

  In step S901, when the CPU 500 detects a load signal (5 [V]), the cleaning drive unit 306 stops the cleaning member 302 and the cover member 308 at the toner isolation position (S902).

  Next, the CPU 500 determines whether or not the signal output from the toner detection sensor 400 is a no-load signal (0 [V]) (S903). In this state, since the toner T is not attached to the detection surface 401 and the cleaning member 302 is not in contact with the detection surface 401, if there is no abnormality in the toner detection sensor 400, a no load signal (0 [V ]) Should be output.

  When the no load signal (0 [V]) is output from the toner detection sensor 400 in step S903, the CPU 500 causes the cleaning drive unit 306 to stop the cleaning member 302 and the cover member 308 at the initial positions (S904).

Next, the CPU 500 detects whether a load presence signal (5 [V]) is output from the toner detection sensor 400 in order to detect the amount of toner T in the hopper unit 301 (S905). In step S <b> 905, the toner detection sensor 400 stores a load signal (5 [V]) if the toner T in the hopper unit 301 is accumulated so as to cover the detection surface 401, and accumulates so as to cover the detection surface 401. If not, a no-load signal (0 [V]) is output.
In step S <b> 905, when the load detection signal (5 [V]) is output from the toner detection sensor 400, the CPU 500 ends the process of supplying the toner T into the hopper unit 301.

  On the other hand, when no load signal (0 [V]) is output from the toner detection sensor 400 in step S905, the CPU 500 determines that the toner T in the hopper unit 301 is insufficient. Accordingly, the CPU 500 drives the toner bottle driving unit 305 for a predetermined time (2 [s] in the present embodiment) to replenish the toner T from the toner bottle 300 to the hopper unit 301 (S906), and proceeds to step S900. By repeating step S900 to step S906, the toner T is supplied from the toner bottle 300 to the hopper unit 301 until the detection surface 401 is covered with the toner T.

  On the other hand, in step S901, when the no-load signal (0 [V]) is output from the toner detection sensor 400, the CPU 500 causes a failure (abnormal 1) in which the output of the toner detection sensor 400 is always 0 [V]. Judge that Therefore, the CPU 500 prohibits the replenishment of the toner T from the toner bottle 300 to the hopper unit 301 (S907).

  On the other hand, in step S903, when the load signal (5 [V]) is output from the toner detection sensor 400, the CPU 500 causes a failure (abnormal 2) where the output of the toner detection sensor 400 is always at a high level (5 [V]). ) Has occurred. Therefore, the CPU 500 proceeds to step S907 and prohibits the replenishment of the toner T from the toner bottle 300 to the hopper unit 301.

  In step S907, if abnormality 1 or abnormality 2 has occurred in the toner detection sensor 400, the CPU 500 prohibits the replenishment of the toner T from the toner bottle 300 to the hopper unit 301. It is good also as a structure which prohibits execution. Alternatively, the image forming operation may be prohibited after the image forming operation is continued for a predetermined number of sheets recorded in advance in the ROM 510. Alternatively, the image forming may be performed until the toner amount of the developing device 14 reaches an arbitrary amount by the inductive sensor 501 and then the execution of the image forming operation is prohibited.

  Further, after step S907, the CPU 500 serving as the abnormality notification unit may output a signal for notifying the display unit 2 that abnormality 1 or abnormality 2 has occurred in the toner detection sensor 400.

  In this embodiment, the cleaning member 302 and the cover member 308 are configured to stop for a time (200 [ms] or more) necessary to detect the toner T adhering to the detection surface 401 at the initial position and the toner isolation position. Yes.

  The phase comparison unit 407 of the present embodiment sets one period to 20 [ms], and when a high level (5 [V]) resonance point presence / absence signal is detected continuously for 10 periods (200 [ms]), Begins outputting a level (5 [V]) load signal (with load signal).

  Therefore, the CPU 500 detects the toner T or the cleaning member 302 that is in contact with the detection surface 401 by stopping the cleaning member 302 for 200 [ms] or more at a position that does not contact the detection surface 401 in steps S903 and S905. is doing.

  Further, the CPU 500 may be configured to stop the cleaning member 302 at the position (b) in FIG. In this configuration, the CPU 500 stops the cleaning member 302 for 200 [ms] or more at the position (b) in FIG. 10A, and the toner detection sensor 400 outputs a signal with load (5 [V]). What is necessary is just to determine.

  According to the present embodiment, it is possible to detect abnormality 1 and abnormality 2 of the toner detection sensor 400 without using the inductor sensor 501 as the toner amount detection unit as in the first embodiment.

Furthermore, in the second embodiment, the moving speed of the cleaning member 302 is constant.
Therefore, since the cleaning member 302 does not have to be shifted as in the first embodiment, control for detecting a failure of the toner detection sensor 400 is easy.

  Although the powder level sensor is used as the toner detection sensor 400 in the first and second embodiments, a non-contact type toner detection sensor 400 that receives light from a light source with a phototransistor may be used. In this configuration, the cleaning member 302 removes the toner T adhering to the inner wall (detection surface 401) of the hopper unit 301 on the visible light that reaches the phototransistor from the light source and shields the visible light from the light source. What is necessary is just to be the structure to do.

  According to the first and second embodiments, the abnormality detection process of the toner detection sensor 400 can be performed using the cleaning member 302 that is also in the configuration of the conventional hopper unit 301.

300 toner bottle 301 hopper unit 302 cleaning member 400 toner detection sensor 401 detection surface 500 CPU

Claims (13)

A toner replenishing container for storing replenishing toner used for image formation;
Toner storage means for storing toner supplied from the toner supply container;
Detection means for detecting whether or not the toner accumulated in the toner accumulation means is in contact with a detection member provided in the toner accumulation means;
Cleaning means having a cleaning member for removing the toner in contact with the detection member by contacting the detection member;
If the cleaning means does not detect that the cleaning member is in contact with the detection member while the cleaning member is in contact with the detection member, an abnormality has occurred in the detection means. An image forming apparatus comprising: a determination unit that determines that the image forming apparatus is present. A toner replenishing container for storing replenishing toner used for image formation;
Toner storage means for storing toner supplied from the toner supply container;
Detection means for detecting whether or not the toner accumulated in the toner accumulation means is in contact with a detection member provided in the toner accumulation means;
Cleaning means having a cleaning member for removing the toner in contact with the detection member by contacting the detection member;
If the cleaning means is not in contact with the detection member while the cleaning member is in contact with the detection member, the toner storage means from the toner supply container is not detected. An image forming apparatus comprising control means for prohibiting toner from being replenished.   The control unit detects that the cleaning member is in contact with the detection member by the detection unit in a state where the cleaning member is in contact with the detection member from which the toner attached by the cleaning unit is removed. 3. The image forming apparatus according to claim 2, wherein if not, toner supply from the toner supply container to the toner storage unit is prohibited.   4. The image formation according to claim 2, wherein the control unit prohibits execution of an image forming operation when the detection unit does not detect that the cleaning member is in contact with the detection member. 5. apparatus.   The control unit prohibits execution of the image forming operation after a predetermined number of image forming operations have been performed when the detecting unit does not detect that the cleaning member is in contact with the detecting member. The image forming apparatus according to claim 2 or 3.   When the detection means does not detect that the cleaning member is in contact with the detection member, the detection means has an abnormality notification means for outputting a signal for notifying that an abnormality has occurred in the detection means. An image forming apparatus according to any one of claims 2 to 5. A developing device and a toner amount detecting means for detecting a toner amount in the developing device;
Replenishment means for replenishing the toner accumulation means with a shortage of toner amount from the target value if the toner amount in the developing device detected by the toner amount detection means is less than a target value by a predetermined amount or more. ,
Even if the controller supplies the insufficient amount of toner from the toner storage unit to the developing device by the supply unit, the toner amount detected by the toner amount detection unit may be less than the predetermined value by the predetermined amount or more. 7. The image forming apparatus according to claim 2, wherein execution of the image forming operation is prohibited. The cleaning unit includes a cover member that covers the detection member so that the toner and the cleaning member do not come into contact with the detection member after the cleaning member removes the toner attached to the detection member.
When the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member in a state where the cover member covers the detection member, the control unit detects the toner supply container. The image forming apparatus according to claim 2, wherein replenishment of toner to the toner storage unit is prohibited. A toner replenishing container for storing replenishing toner used for image formation;
Toner storage means for storing toner supplied from the toner supply container;
Detection means for detecting whether or not the toner accumulated in the toner accumulation means is in contact with a detection member provided in the toner accumulation means;
Covering the cleaning member that removes the toner that is in contact with the detection member by contacting the detection member, and the detection member from which the toner adhering to the detection member has been removed, Cleaning means having a cover member spaced from the toner and the cleaning member;
If the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member with the cover member covering the detection member by the cleaning unit, the detection unit is abnormal. An image forming apparatus, comprising: a determination unit configured to determine that the occurrence of the error occurs. A toner replenishing container for storing replenishing toner used for image formation;
Toner storage means for storing toner supplied from the toner supply container;
Detection means for detecting whether or not the toner accumulated in the toner accumulation means is in contact with a detection member provided in the toner accumulation means;
Covering the cleaning member that removes the toner that is in contact with the detection member by contacting the detection member, and the detection member from which the toner adhering to the detection member has been removed, Cleaning means having a cover member spaced from the toner and the cleaning member;
When the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member in a state where the cover member covers the detection member by the cleaning unit, the toner supply container An image forming apparatus comprising control means for prohibiting toner supply to the toner storage means. The cleaning unit includes a cover member that covers the detection member so that the toner and the cleaning member do not come into contact with the detection member after the cleaning member removes the toner attached to the detection member.
The control unit is configured to perform an image forming operation when the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member while the cover member covers the detection member. 11. The image forming apparatus according to claim 8, wherein execution is prohibited.   When the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member in a state where the cover member covers the detection member, a predetermined number of images are obtained. The image forming apparatus according to claim 8, wherein the execution of the image forming operation is prohibited after the forming operation is executed.   When the detection unit detects that at least one of the toner and the cleaning member is in contact with the detection member in a state where the cover member covers the detection member, the control unit The image forming apparatus according to claim 8, further comprising an abnormality notifying unit that outputs a signal for notifying that an abnormality has occurred.

Images