JP2014016557A - Developer deterioration determination device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine a situation of deterioration of a developer contained in a development unit disposed in an image forming apparatus.SOLUTION: A first pressure sensor 61a is disposed on one end of a trimmer block 54 in a width direction (a primary scanning direction) while a second pressure sensor 61b is disposed on the other end. A detection value obtainment part 62 obtains: pressure p1 of a developer contained in a development unit 14, the pressure detected by the first pressure sensor 61a; and pressure p2 of the developer contained in the development unit 14, the pressure detected by the second pressure sensor 61b. A developer deterioration determination part 63 compares between the pressure p1 and pressure p2 obtained by the detection value obtainment part 62 to examine a degree of difference between the two pressure values and determines that the developer contained in the development unit 14 is deteriorated if the degree exceeds a reference.

Description

  The present invention relates to a developer deterioration determination device and a program.

An image forming apparatus is an apparatus having an image forming function for forming an image with toner on a recording material such as paper, such as a copying machine, a facsimile machine, a printer, or a multifunction machine having these functions.
In such an image forming apparatus, a developer in which a carrier, a charge accelerator or the like is mixed with toner is used. For example, in the developing device provided in the image forming apparatus, the toner is adhered to the developing roll from the developer contained in the container, and the toner is transported onto the photosensitive drum by the rotation of the developing roll, and is formed on the photosensitive drum. The electrostatic latent image is developed with toner.
In such a developing device, it is known that when the toner is deteriorated or insufficient, the fluidity of the developer is lowered, which leads to development failure.

Here, the following inventions have been proposed regarding the determination of the deterioration state of the developer.
For example, in Patent Document 1, when the fluidity of the developer contained in the case deteriorates, a portion where the developer stays appears in the case, and the pressure at which the developer in the staying portion presses the inner wall of the case increases. Therefore, an invention is disclosed in which the degree of toner deterioration is grasped by detecting this change in pressure by a detecting means.

JP 2008-076428 A

  An object of the present invention is to propose a technique capable of accurately determining a deterioration state of a developer in a developing device provided in an image forming apparatus.

  According to a first aspect of the present invention, there is provided an acquisition means for acquiring developer pressures detected at a plurality of locations in a developing device provided in the image forming apparatus, and detection of the plurality of locations acquired by the acquisition means. And a determination means for determining deterioration of the developer by comparing pressures with each other.

  According to a second aspect of the present invention, in the first aspect of the present invention, the developing device includes a container that stores the developer, a developing roll that adheres the developer in the container and conveys the developer to the photoreceptor side, A plurality of leveling members along the width direction of the developing roll for leveling the developer adhering to the developing roll on the upstream side of the photoreceptor, and detecting a pressure of the developer. Detection means is provided at a different position in the width direction of the leveling member with respect to the leveling member, and the acquisition means acquires the developer pressure detected by the plurality of detection means. A developer deterioration determination device.

  According to a third aspect of the present invention, in the first aspect of the invention according to the first aspect, the developing device includes a container that stores the developer, a developing roll that adheres the developer in the container and conveys the developer to the photoreceptor side, A plurality of detection means for detecting the pressure of the developer in the conveyance direction of the developer by the conveyance unit. The developer deterioration determination device is provided at different positions, and the acquisition unit acquires the pressure of the developer detected by the plurality of detection units.

  According to a fourth aspect of the present invention, there is provided an acquisition function for acquiring, in a computer, developer pressures detected at a plurality of locations in a developing device provided in an image forming apparatus, and a plurality of acquisition functions acquired by the acquisition function. This is a program for realizing a determination function for comparing the detected pressures at different locations and determining deterioration of the developer.

  According to the first and fourth aspects of the present invention, it is possible to determine the deterioration state of the developer in the developing device provided in the image forming apparatus with higher accuracy than when the present invention is not applied.

  According to the second aspect of the present invention, the developer pressure divergence at different positions in the width direction of the member leveling the developer adhering to the developing roll can be detected, and the deterioration state of the developer in the developing device Can be determined with high accuracy.

  According to the third aspect of the present invention, it is possible to grasp the difference in developer pressure at different positions in the transport direction in the transport unit that transports the developer in the container to the developing roll, and the developer in the developer unit Degradation status can be accurately determined.

FIG. 3 is a diagram illustrating a structure example of a developing device in an image forming apparatus according to an embodiment of the present disclosure. It is a figure which shows the example of the cross-section of the axial direction of the trimmer block and developing roll in a developing device. It is a figure which shows the example of the cross-sectional structure of the axial direction of the developer stirring conveyance part in a developing device. It is a figure which shows the example of the functional block in connection with determination of the deterioration condition of the developer in a developing device. It is a figure which shows the example of the time change of the developer pressure detected by the trimmer block. It is a figure which shows the example of the time change of the difference of the developer pressure detected by the trimmer block. It is a figure which shows the example of the time change of the developer pressure detected in the developer stirring conveyance part. It is a figure which shows the example of the correspondence of the developer pressure detected by the developer stirring conveyance part. It is a figure which shows the example of the time change of the index value which shows the correlation of the developer pressure detected in the developer stirring conveyance part. 2 is a diagram illustrating an example of an apparatus structure related to an image forming function of an image forming apparatus. FIG.

An embodiment of the present invention will be described with reference to the drawings.
First, an image forming apparatus provided with a developer deterioration determination device according to the present invention will be described.
An image forming apparatus is an apparatus having an image forming function for forming an image with toner on a recording material such as paper, such as a copying machine, a facsimile machine, a printer, or a multifunction machine having these functions.

FIG. 10 illustrates an apparatus structure relating to an image forming function of the image forming apparatus.
The illustrated image forming apparatus is an intermediate transfer method generally called a tandem type, and as a representative functional unit, a plurality of image forming units 10Y, 10M, 10C, and 10K in which toner images of respective color components are formed by an electrophotographic method. A primary transfer portion 21 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 10Y, 10M, 10C, and 10K to the intermediate transfer belt 15, and a superimposition transferred on the intermediate transfer belt 15. A secondary transfer unit 22 that collectively transfers (secondary transfer) toner images onto a sheet P (an example of a recording material), and a fixing unit 34 that fixes the secondary transferred image onto the sheet P are provided.

Each of the image forming units 10Y, 10M, 10C, and 10K has a photosensitive drum 11 that rotates in the direction of arrow A in the drawing. Further, around each of the photosensitive drums 11, a charger 12 that charges the photosensitive drum 11, an exposure unit 13 that writes an exposure beam Bm on the photosensitive drum 11 to write an electrostatic latent image, and each color component toner And a developing unit 14 that forms a toner image in which the electrostatic latent image on the photosensitive drum 11 is visualized with toner, and a toner image of each color component formed on the photosensitive drum 11 is a primary transfer unit 21. Various electrophotographic devices such as a primary transfer roll 16 that is superimposed and transferred to the intermediate transfer belt 15 and a drum cleaner 17 that removes residual toner on the photosensitive drum 11 are sequentially arranged.
These image forming units 10Y, 10M, 10C, and 10K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. The intermediate transfer belt 15 can be contacted and separated.

  The illustrated image forming apparatus passes through the secondary transfer unit 22 and the paper feed mechanism unit 31 that performs a paper feed operation of taking out the paper P from the paper storage unit and feeding it to the secondary transfer unit 22 as a paper transport system. The conveying belt 32 that conveys the sheet P to the fixing unit 34 side, the fixing inlet guide 33 that guides the sheet P to the inlet of the fixing unit 34, and the sheet discharge that guides the sheet P discharged from the fixing unit 34. A guide 35 and a paper discharge roll 36 for discharging the paper P guided by the paper discharge guide 35 to the outside of the apparatus are provided.

  That is, the paper P fed from the paper storage unit to the secondary transfer unit 22 by the paper feed mechanism unit 31 is electrostatically transferred to the toner image on the intermediate transfer belt 15 by the secondary transfer unit 22. The paper is transported to the transport belt 32 while being peeled from the intermediate transfer belt 15. Then, the toner is conveyed by the conveyance belt 32 to the fixing device 34 through the fixing inlet guide 33 in accordance with the operation speed of the fixing device 34. The unfixed toner image on the paper P conveyed to the fixing device 34 is fixed on the paper P by receiving a fixing process in which heat and pressure are applied by the fixing device 34. Thereafter, the paper P on which the fixed image is formed is conveyed to a paper discharge container (not shown) provided outside the apparatus via a paper discharge guide 35 and a paper discharge roll 36.

The developing device 14 in the image forming apparatus of this example will be further described.
FIG. 1 shows an example of the structure of the developing device 14.
The developing device 14 of this example basically has a container 51 that contains a developer in which a carrier, a charge accelerator, and the like are mixed with toner, and a developer in the container 51 is adhered to the photosensitive drum 11 side. A developing roll 52 to be transported, a trimmer 53 for leveling the developer adhering to the developing roll 52 on the upstream side of the photosensitive drum 11, and a developer agitation transporting portion 55 a for transporting the developer in the container 51 to the roll member 52. , 55b.

The developing roll 52 is driven and rotated about an axis as shown by an arrow in FIG. 1, and the developer sent by the developer agitating / conveying portions 55a and 55b is attached to the peripheral surface and conveyed to the photosensitive drum 11 side. .
In this example, a mag roll that holds the developer on the peripheral surface by magnetic force is used as the developing roll 52, but the type of the developing roll 52 is not particularly limited.
The developer toner conveyed by the developing roll 52 is attracted to the photosensitive drum 11 by magnetic force, and the electrostatic latent image on the photosensitive drum 11 is developed. The remaining developer having the toner adsorbed on the photosensitive drum 11 is collected in the container 51 as the developing roll 52 rotates.

The trimmer 53 has a long rectangular shape along the width direction of the developing roll 52, and is provided upstream of the photosensitive drum 11 in the developer transport direction by the developing roll 52. The trimmer 53 equalizes the developer adhering to the peripheral surface of the developing roll 52 to make the amount and surface properties of the developer conveyed to the photosensitive drum 11 side by the developing roll 52 uniform.
In this example, the trimmer 53 is attached to the container 51 by the trimmer block 54. However, the trimmer 53 is attached without using the trimmer block 54 in consideration of the relationship with other components. And may be determined as appropriate.

  The developer agitating / conveying portions 55a and 55b have a spiral shaft (auger) in which a flange portion is spirally formed on the peripheral surface, and the helical shaft is driven and rotated in the container 51, thereby The developer is mixed with stirring and conveyed to the developing roll 52 side. That is, in the developing device 14 of the present example, the developer in the container 51 is forced to flow by the developer agitating and conveying portions 55a and 55b. Note that the developer agitating / conveying portions 55a and 55b may be realized by using other than the spiral shaft.

  Here, it is known that the pressure of the developer in the developing device 14 varies with time. The mechanism by which the developer pressure fluctuates is due to a decrease in the toner charge amount of the developer. That is, when the charge amount of the toner decreases, the intermolecular force between the toners increases and the developer starts to aggregate, and as a result, the fluidity of the developer decreases, which causes an increase in the developer pressure. Such a decrease in the charge amount of the toner occurs when the developer is deteriorated or due to a change in environmental factors.

  By the way, the method of deterioration of the developer is not necessarily uniform and usually varies. In particular, when a mixture of an old developer and a newly supplied developer is used, variation in deterioration becomes significant. For this reason, even if the pressure of a certain developer is detected, only a very small part of the developer is detected. For example, the pressure of the old developer increases with respect to the newly supplied developer. The detection results of the pressures vary.

When such a non-uniform developer pressure is acquired in time series in the developer 14 which is a system in which the developer circulates, the pressure of the developer swells (repeatedly rising and falling). It tends to change. This undulation begins to behave differently depending on the location where the developer pressure is detected as the developer progresses.
Therefore, in the image forming apparatus of this example, pressure sensors 61 that detect the pressure of the developer are provided at a plurality of locations in the developing device 14, and the pressure detected by each pressure sensor 61 is acquired and compared. Thus, the deterioration state of the developer in the developing device 14 is determined.

  Here, each pressure sensor 61 has a relationship in which the detected values are relatively close to each other when the developer is not deteriorated, and the detected values are different from each other as the developer is deteriorated. It is arranged in the place of. In addition, it is preferable to provide it at a place where the developer pressure is high or a place where a pressure difference due to the deterioration of the developer is noticeable, because the accuracy of discriminating the difference between the detected values increases.

  As an example, as shown in FIG. 1, two pressure sensors 61 a and 61 b that detect the pressure of the developer in the developing device 14 are attached to a trimmer block 54 that holds a trimmer 53. FIG. 2 shows an example of an axial sectional structure of the trimmer block 54 and the developing roll 52. As shown in the figure, a first pressure sensor 61a is provided at one end in the width direction (main scanning direction) of the trimmer block 54, and a second pressure sensor 61b is provided at the other end. Each of the pressure sensors 61a and 61b is disposed so as to face an area where the developer flowing in the container 51 is leveled by the trimmer 53, and detects the pressure of the developer in this area.

  As another example, two pressure sensors 61 a ′ and 61 b ′ that detect the pressure of the developer in the developing device 14 are attached to the developer agitating and conveying portions 55 a and 55 b. FIG. 3 shows an example of an axial sectional structure of the developer agitating / conveying portions 55a and 55b. As shown in the drawing, a first pressure sensor 61a 'is provided in the upstream developer agitation transport part 55a, and a second pressure sensor 61b' is provided in the downstream developer agitation transport part 55b. The pressure sensors 61a ′ and 61b ′ are arranged on the end surface downstream in the transport direction in which the developer pressure is highest in the developer stirring and transporting portions 55a and 55b, respectively, and detect the pressure of the developer on the end surface. To do.

  The pressures detected by these pressure sensors 61a and 61b (or 61a 'and 61b') are converted into data and output to the detected value acquisition unit 62 as shown in FIG. The detection value acquisition unit 62 acquires the data of the detection pressure output from the pressure sensors 61a and 61b and stores it in the memory inside the apparatus. The developer deterioration determination unit 63 reads out the data of the pressure detected by the pressure sensors 61a and 61b from the memory and compares them with each other to determine the deterioration state of the developer in the developing device 14.

The comparison determination by the developer deterioration determination unit 63 will be further described.
The developer deterioration determination unit 63 compares the pressure p1 detected by the first pressure sensor 61a (or 61a ′) with the pressure p2 detected by the second pressure sensor 61b (or 61b ′), and makes a difference between them. The condition is checked, and when the deviation exceeds the standard, it is determined that the developer in the developing device 14 is deteriorated.

As an example, the developer deterioration determining unit 63 obtains a difference D (= p1−p2) for the pressure p1 and the pressure p2, and when the difference D is out of a predetermined normal range, the developer in the developing device 14 is removed. Judge that it is deteriorated.
FIG. 5 shows the time between the pressure p1 detected by the first pressure sensor 61a provided at one end of the trimmer block 54 and the pressure p2 detected by the second pressure sensor 61b provided at the other end of the trimmer block 54. The change is illustrated. In addition, FIG. 6 illustrates the time change of the difference between the pressure p1 and the pressure p2. In this manner, the difference between the pressure p1 and the pressure p2 has a larger fluctuation range with time.
Therefore, the developer deterioration determination unit 63 checks whether or not the difference D between the pressure p1 and the pressure p2 is within the normal range. Then, it is determined that the developer in the developing device 14 has deteriorated at the timing T1 when the difference D exceeds the upper threshold that determines the upper limit of the normal range and the timing T2 that falls below the lower threshold that sets the lower limit of the normal range. To do.

As another example, the developer deterioration determining unit 63 obtains an index value indicating the correlation between the pressure p1 and the pressure p2, and when the index value is out of a predetermined normal range, the developer in the developing unit 14 is obtained. Is determined to be deteriorated.
FIG. 7 shows the pressure p1 detected by the first pressure sensor 61a ′ provided in the developer stirring and conveying section 55a and the pressure detected by the second pressure sensor 61b ′ provided in the developer stirring and conveying section 55b. The time change of p2 is illustrated. FIG. 8A illustrates the correspondence relationship between the pressure p1 and the pressure p2 detected at each sampling timing up to the time A, and FIG. The correspondence relationship between the pressure p1 and the pressure p2 detected at each sampling timing up to the time B is illustrated. Further, in FIG. 9, is illustrated when (square value of the correlation coefficient R) when the index value obtained from sequence data of time series data and the pressure p2 time variation of R ² of the pressure p1.

Thus, when the correspondence relationship between the pressure p1 and the pressure p2 up to the time point A and the correspondence relationship between the pressure p1 and the pressure p2 up to the time point B are compared, the time B after the time A corresponds. The variation of the relationship is remarkable. Therefore, the correlation coefficient R _A obtained from the time series data of the pressure p1 and the time series data of the pressure p2 up to the time _A, and the time series data of the pressure p1 and the time series of the pressure p2 up to the time B comparing the correlation coefficient R _B obtained from the data, there is a tendency that the direction of the correlation coefficient R _B smaller than the correlation coefficient R _a.
Accordingly, developer deterioration determining section 63 obtains as an index value the square value R ² of the correlation coefficient for the pressure p1 and the pressure p2, checks whether the index value R ² is within the normal range. It is determined at the timing T3 to the index value R ² is below the threshold value defining the lower limit of the normal range, the developer in the developing unit 14 is deteriorated.
Here, the algorithm shown in FIG. 6 is applied to the configuration of FIG. 2, and the algorithm shown in FIG. 7 is applied to the configuration of FIG. 3, but these may be reversed.

In the above description, the method for examining the degree of divergence between the pressure p1 and the pressure p2 using the difference or the correlation coefficient is shown, but the degree of divergence may be examined by other methods.
Here, when the pressure sensors 61a and 61b are attached to the trimmer block 54 and the pressure sensors 61a 'and 61b' are attached to the developer agitating / conveying portions 55a and 55b, the developer pressure is determined based on the former sensor position. The pressure difference due to the deterioration of the developer is more noticeable at the latter sensor position. As described above, since the pressure tendency varies depending on the difference in sensor position, it is preferable to examine the degree of deviation using a method corresponding to the sensor position.

Further, the location of the pressure sensor that detects the pressure of the developer in the developing device 14 is not limited to the above-described content, and there are various relationships in which the relevance of the detected value decreases as the developer deteriorates. It can be arranged in the place. For example, when the developer is not deteriorated, the detected values have a negative correlation (correlation coefficient is close to −1), and the correlation disappears with the deterioration of the developer (the correlation coefficient is You may arrange | position in the place which has such a relationship.
Also, the number of pressure sensors need not be two. For example, when three or more pressure sensors are provided, and the detected pressure value differs in the combination of the two pressure sensors, the developer deteriorates. It may be determined that

In addition, the determination result by the developer deterioration determination unit 63 includes various predictions such as prediction of occurrence of image quality abnormality (degradation of image graininess and toner drop), and identification of cause of failure (developer deterioration) when image quality abnormality occurs. It can be used for
In addition, the determination result by the developer deterioration determination unit 63 or the result of the above-described processing (prediction of occurrence of image quality abnormality or identification of the cause of failure when the image quality abnormality occurs) is displayed on the image forming apparatus. Then, the user may be notified, or may be transmitted to an external device such as a monitoring server that is communicably connected to the image forming apparatus to notify the system administrator, maintenance staff, or the like.

  Here, in the image forming apparatus of this example, a CPU (Central Processing Unit) that performs various arithmetic processes, a RAM (Random Access Memory) that is a work area of the CPU, a ROM (Read Only) that records a basic control program, and the like. Memory) and other main storage devices, HDD (Hard Disk Drive) and other auxiliary storage devices for storing various programs and data, display devices for displaying and outputting various information, and operation buttons used for input operations by the operator And a computer having hardware resources such as an input / output I / F that is an interface with an input device such as a touch panel and a communication I / F that is an interface for performing wired or wireless communication with other devices. ing.

Then, the program according to the present invention is read from the auxiliary storage device or the like, loaded into the RAM, and executed by the CPU, thereby realizing the function of the developer deterioration determination device according to the present invention on the computer of the image forming apparatus. ing.
Specifically, the function of the acquisition unit according to the present invention is realized by the detection value acquisition unit 62, and the function of the determination unit according to the present invention is realized by the developer deterioration determination unit 63.

Here, the program according to the present invention is set in the computer of the image forming apparatus, for example, by a format read from an external storage medium such as a CD-ROM storing the program or a format received via a communication network. The
Note that the present invention is not limited to a mode in which each functional unit is realized by a software configuration as in this example, and each functional unit may be realized by a dedicated hardware module.

  In this example, the image forming apparatus itself has the detection value acquisition unit 62 and the developer deterioration determination unit 63. However, the detection value is acquired by an external device such as a monitoring server that is communicably connected to the image forming apparatus. The image forming unit 62 and the developer deterioration determining unit 63 may be provided so that the external device receives the developer pressure data from the image forming apparatus and determines the developer deterioration state.

  14: Developing device, 51: Container, 52: Developing roll, 53: Trimmer, 54: Trimmer block, 55: Developer stirring and conveying section, 61a, 61a ′: First pressure sensor, 61b, 61b ′: Second pressure sensor 62: Detection value acquisition unit 63: Developer deterioration determination unit

Claims (4)

Obtaining means for obtaining developer pressures detected at a plurality of locations in a developing device provided in the image forming apparatus;
A determination unit that compares the detected pressures of a plurality of locations acquired by the acquisition unit with each other and determines deterioration of the developer;
A developer deterioration determination device comprising: The developer unit contains a developer container, a developing roll for adhering the developer in the container and transporting the developer to the photoreceptor side, and a developer adhering to the developing roll upstream from the photoreceptor. Elongate leveling member along the width direction of the developing roll,
A plurality of detection means for detecting the developer pressure are provided at different positions in the width direction of the leveling member with respect to the leveling member,
The acquisition unit acquires the developer pressure detected by the plurality of detection units.
The developer deterioration determination apparatus according to claim 1. The developing device includes a container for storing a developer, a developing roll that adheres the developer in the container and transports the developer to the photoreceptor side, and a transport unit that transports the developer in the container to the developing roll. Have
A plurality of detection means for detecting the pressure of the developer is provided at different positions in the transport direction of the developer by the transport unit with respect to the transport unit,
The acquisition unit acquires the developer pressure detected by the plurality of detection units.
The developer deterioration determination apparatus according to claim 1. On the computer,
An acquisition function for acquiring the pressure of the developer detected at a plurality of locations in the developing device provided in the image forming apparatus;
A determination function for comparing the detected pressures of a plurality of locations acquired by the acquisition function with each other to determine deterioration of the developer,
A program to realize

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