JP2021096428A - Image forming apparatus and toner remaining amount detection method - Google Patents

Abstract

To prevent an error in detection of the remaining amount of toner.SOLUTION: An image forming apparatus according to an aspect of the present invention comprises: a temperature detection unit that detects the temperature around toner containers; a plurality of electrodes that are arranged while sandwiching the toner containers; and an output unit that outputs information on the amount of toner remaining in the toner containers. When the temperature is within a predetermined range, the output unit outputs first toner remaining amount information detected based on the capacitance value between the plurality of electrodes, and when the temperature is not within the predetermined temperature range, outputs second toner remaining amount information detected based on image formation accumulation information.SELECTED DRAWING: Figure 10

Description

The present invention relates to an image forming apparatus and a method for detecting the remaining amount of toner.

Conventionally, as a technique for detecting the remaining amount of toner in a toner bottle in an electrophotographic image forming apparatus, a cumulative information method using information such as a cumulative image area formed on a recording medium and a plurality of toner bottles arranged across the toner bottle are used. A capacitance method using the capacitance between electrodes is known.

In addition, by combining the above cumulative information method and capacitance method, when a predetermined environment such as high temperature and high humidity is reached, the detection method is switched from the cumulative information method to the capacitance method to detect the remaining amount of toner. The technology is disclosed (see, for example, Patent Document 1).

However, in the technique of Patent Document 1, the holding portion of the electrodes expands due to the temperature fluctuation around the toner bottle, and the distance between the electrodes changes, so that the detection accuracy of the remaining amount of toner may decrease.

An object of the present invention is to suppress a detection error of the remaining amount of toner.

The image forming apparatus according to one aspect of the present invention outputs a temperature detection unit that detects the ambient temperature of the toner container, a plurality of electrodes arranged so as to sandwich the toner container, and toner remaining amount information in the toner container. The output unit includes, and the output unit outputs the first toner remaining amount information detected based on the capacitance value between the plurality of electrodes when the temperature is within a predetermined range, and the temperature is adjusted. The second toner remaining amount information detected based on the cumulative information of image formation when the temperature is not within the predetermined temperature range is output.

According to the present invention, it is possible to suppress a detection error of the remaining amount of toner.

It is a figure which shows the structural example of the image forming apparatus which concerns on embodiment. It is a figure which shows the structural example of the image-forming part which concerns on embodiment. It is a figure which shows the structural example of the toner supply part which concerns on embodiment. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is a perspective view which shows the example of the installation state of the toner container in the toner container accommodating part. It is a figure explaining an example of the calibration curve which concerns on embodiment. It is a block diagram which shows the hardware configuration example of the control part which concerns on embodiment. It is a figure explaining an example of the change of the calibration curve with temperature. It is a figure which shows an example of the detection error of the toner remaining amount. It is a block diagram which shows the functional structure example of the control part which concerns on embodiment. It is a flowchart which shows the processing example of the control part which concerns on embodiment. It is a figure explaining the detection accuracy of the remaining amount of toner which concerns on 1st Embodiment. It is a figure explaining the detection accuracy of the remaining amount of toner which concerns on 2nd Embodiment. It is a figure of the relationship example of the temperature fluctuation amount and expansion convergence time which concerns on 3rd Embodiment.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate description may be omitted.

The image forming apparatus according to the embodiment includes a toner remaining amount detecting device for detecting the remaining amount of toner in the toner container. In this toner remaining amount detecting device, when the ambient temperature of the toner container is within a predetermined range, the first toner remaining amount information is detected based on the capacitance value between a plurality of electrodes arranged across the toner container. Is output, and when the ambient temperature of the toner container is not within the predetermined range, the second toner remaining amount information detected based on the cumulative information of image formation is output.

With this configuration, the remaining amount of toner is detected based on the capacitance only within the effective temperature range of a predetermined calibration curve showing the relationship between the capacitance value and the remaining amount of toner, so that the ambient temperature of the toner bottle fluctuates. It suppresses the error caused by it and detects the remaining amount of toner with high accuracy.

Hereinafter, an embodiment will be described by taking an image forming apparatus 100 including the toner remaining amount detecting apparatus 200 as an example.

<Overall configuration example of image forming apparatus 100>
First, the overall configuration of the image forming apparatus 100 will be described.

FIG. 1 is a diagram illustrating an example of the overall configuration of the image forming apparatus 100. As shown in FIG. 1, the image forming apparatus 100 includes a toner container accommodating unit 70, an intermediate transfer unit 15, an image forming unit 6, and a toner replenishing unit 60. Four toner containers 32 (Y, M, C, K) corresponding to each color (yellow, magenta, cyan, black) are detachably (replaceable) installed in the toner container storage unit 70.

In FIG. 1, an intermediate transfer unit 15 is provided below the toner container accommodating portion 70. Image forming portions 6 (Y, M, C, K) corresponding to each color are arranged in parallel so as to face the intermediate transfer belt 8 of the intermediate transfer unit 15.

Further, below the toner container 32 (Y, M, C, K), toner replenishment units 60 (Y, M, C, K) are provided, respectively. Then, the toner contained in the toner container 32 (Y, M, C, K) is subjected to the image forming unit 6 (Y, M, C, K) by the toner replenishment unit 60 (Y, M, C, K), respectively. ) Is supplied (supplied) into the developing unit 5.

The four toner containers 32 (Y, M, C, K) corresponding to each color, the image forming unit (Y, M, C, K) and the toner replenishing unit 60 (Y, M, C, K) are the toners to be used. It has the same configuration except that the color of is different. Therefore, in the following description and drawings, the subscripts "Y", "M", "C", and "K" indicating the color of the toner to be used will be omitted as appropriate.

FIG. 2 is a diagram illustrating an example of the configuration of one of the four image forming units 6.

The image forming unit 6 includes a photoconductor 1, a charging unit 4 provided around the photoconductor 1, a developing unit 5, a cleaning unit 2, and a static elimination unit. Then, an image forming process, that is, a charging process, an exposure process, a developing process, a transfer process, and a cleaning process are performed on the photoconductor 1, and images of each color are formed on the photoconductor 1.

The photoconductor 1 is rotationally driven by a drive motor in the direction of the arrow (clockwise) shown in the photoconductor 1 of FIG. Then, the surface of the photoconductor 1 is uniformly charged at the position of the charging unit 4 (charging step). After that, the surface of the photoconductor 1 reaches an irradiation position of the laser beam L emitted from the exposure unit 7, and an electrostatic latent image corresponding to each color is formed by exposure scanning at this position (exposure step).

After that, the surface of the photoconductor 1 reaches a position facing the developing unit 5, and the electrostatic latent image is developed at this position to form a toner image of each color (development step). After that, the surface of the photoconductor 1 is a primary transfer portion facing the primary transfer roller 9 with the intermediate transfer belt 8 interposed therebetween, and the toner image on the photoconductor 1 is transferred onto the intermediate transfer belt 8 (primary transfer step). .. A color image is formed on the intermediate transfer belt 8 by superimposing and transferring the toner images of each color formed on the photoconductor 1 of each color on the intermediate transfer belt 8.

A small amount of untransferred toner remains on the surface of the photoconductor 1 that has passed through the primary transfer portion. After that, the surface of the photoconductor 1 reaches a position facing the cleaning unit 2, and the untransferred toner remaining on the photoconductor 1 is mechanically recovered by the cleaning blade 2a (cleaning step). Finally, the surface of the photoconductor 1 reaches a position facing the static elimination portion, and the residual potential on the photoconductor 1 is removed.

The intermediate transfer unit 15 includes an intermediate transfer belt 8, four primary transfer rollers 9 (Y, M, C, K), a secondary transfer backup roller 12, a plurality of tension rollers, and an intermediate transfer cleaning unit. .. The intermediate transfer belt 8 is stretched and supported by a plurality of tension rollers, and is driven by the rotation of the secondary transfer backup roller 12 among the roller members in the direction of the arrow shown in the intermediate transfer belt 8 of FIG. It moves endlessly (counterclockwise). Each of the four primary transfer rollers 9 (Y, M, C, K) forms a primary transfer nip by sandwiching the intermediate transfer belt 8 with the photoconductor 1 (Y, M, C, K). ..

Then, a transfer bias opposite to the polarity of the toner is applied to the primary transfer roller 9 (Y, M, C, K). The intermediate transfer belt 8 travels in the direction of the arrow shown in the intermediate transfer belt 8 of FIG. 1 and sequentially passes through the primary transfer nips of the respective primary transfer rollers 9 (Y, M, C, K). In this way, the toner images of each color on the photoconductor 1 (Y, M, C, K) are superposed on the intermediate transfer belt 8 and primaryly transferred.

The intermediate transfer belt 8 on which the toner images of each color are superimposed and primary-transferred reaches the secondary transfer portion facing the secondary transfer roller 19. In the secondary transfer section, an intermediate transfer belt 8 is sandwiched between the secondary transfer backup roller 12 and the secondary transfer roller 19, and a secondary transfer nip is formed. The four-color toner images formed on the intermediate transfer belt 8 are secondarily transferred onto a recording medium P such as transfer paper conveyed to the position of the secondary transfer nip.

At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 8. After that, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning section, and the untransferred toner on the intermediate transfer belt 8 is collected. In this way, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

The recording medium P conveyed to the position of the secondary transfer nip is conveyed from the paper feeding unit 26 provided below the image forming apparatus 100 via the paper feeding roller 27, the resist roller pair 28, and the like. is there. Specifically, a plurality of recording media P are stacked and stored in the paper feed unit 26. Then, when the paper feed roller 27 is rotationally driven in the counterclockwise direction in FIG. 1, the top recording medium P is fed between the resist rollers and the rollers 28.

The recording medium P conveyed to the resist roller pair 28 is temporarily stopped by the roller nip of the resist roller pair 28 that has stopped the rotational drive. Then, the resist roller pair 28 is rotationally driven in time with the color image on the intermediate transfer belt 8, and the recording medium P is conveyed toward the secondary transfer nip. In this way, the desired color image is transferred onto the recording medium P.

The recording medium P on which the color image is transferred by the secondary transfer nip is conveyed to the fixing unit 20. Then, at this position, the color image transferred to the surface is fixed on the recording medium P by the heat and pressure of the fixing belt and the pressure roller.

After that, the recording medium P is discharged to the outside of the device through the space between the paper ejection rollers and the rollers 29. The recording medium P discharged to the outside of the device by the paper ejection roller pair 29 is sequentially stacked on the stack unit 30 as an output image. In this way, a series of image forming processes in the image forming apparatus 100 are completed.

Next, the configuration and operation of the developing unit in the image forming unit will be described in more detail.

As shown in FIG. 2, the developing unit 5 includes a developing roller 51 facing the drum-shaped photoconductor 1, a doctor blade 52 facing the developing roller 51, a first developing agent accommodating unit 53, and a second developing agent accommodating unit 5. It has two transport screws 55 provided in the portion 54. It also has a toner concentration detection sensor 56 that detects the toner concentration in the developer in the first developer housing unit 53.

The developing roller 51 is composed of a magnet fixed inside, a sleeve that rotates around the magnet, and the like. In the developer accommodating portion (53, 54), a two-component developer G composed of a carrier and a toner is accommodated. The second developer accommodating portion 54 communicates with the toner drop transport path 64 through an opening formed above the second developer accommodating portion 54.

The sleeve of the developing roller 51 is rotationally driven in the direction of the arrow (counterclockwise) shown in the developing roller 51 in FIG. Then, the developer G supported on the developing roller 51 by the magnetic field formed by the magnet moves on the developing roller 51 as the sleeve rotates.

The developer G in the developing unit 5 is adjusted so that the ratio of toner (toner concentration) in the developing agent is within a predetermined range. Depending on the toner consumption in the developing unit 5, the toner contained in the toner container 32 is replenished in the second developing agent accommodating unit 54 via the toner replenishing unit 60. The configuration and operation of the toner replenishment unit 60 will be described in detail later.

The toner replenished in the second developing agent accommodating portion 54 circulates in the two developing agent accommodating portions (53, 54) while being mixed and stirred together with the developing agent G by the transport screw 55. Then, the toner in the developer G is adsorbed on the carrier by triboelectric charging with the carrier, and is supported on the developing roller 51 together with the carrier by the magnetic force formed on the developing roller 51. The developer G supported on the developing roller 51 is conveyed in the direction of the arrow shown in the developing roller 51 in FIG. 2 and reaches the position of the doctor blade 52.

Then, the developer G on the developing roller 51 is conveyed to a position facing the photoconductor 1 (development region) after the amount of the developer is adjusted to an appropriate amount at this position, and the photoconductor G is conveyed by the electric field formed in the developing region. Toner is adsorbed on the latent image formed on 1. After that, the developer G remaining on the developing roller 51 reaches above the first developing agent accommodating portion 53 as the sleeve rotates, and is separated from the developing roller 51 at this position.

Next, the toner replenishment unit 60 and the toner container 32 will be described in detail.

FIG. 3 is a diagram illustrating an example of the configuration of one of the four toner supply units 60. Further, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 5 is a perspective view illustrating an example of a state in which the toner container 32 (Y, M, C, K) is installed in the toner container accommodating portion 70. It is a figure.

The toner in the toner container 32 installed in the toner container accommodating unit 70 (see FIG. 1) of the image forming apparatus 100 is a toner replenishment unit provided for each toner color according to the toner consumption in the developing unit 5 of each color. 60 is appropriately replenished in the developing unit 5 of each color.

By moving the toner container 32 in the direction of the arrow "Q" in FIG. 5 with respect to the toner container accommodating portion 70 of the image forming apparatus 100 main body, the toner container 32 can be mounted on the toner container accommodating portion 70. ..

The toner container 32 is supported by two guide portions 72 shown in FIG. The toner container 32 is a substantially cylindrical toner bottle, and as shown in FIG. 3, a container body 33 in which a cap 34 held in the toner container accommodating portion 70 in a non-rotating manner and a gear 33c are integrally formed. And have.

The container body 33 is held so as to be rotatable relative to the cap 34 so that the gear 33c can engage with the drive output gear 81 of the toner replenishment unit 60. When the drive motor 91 rotates the drive output gear 81, the driving force is transmitted to the gear 33c of the container body 33, and the container body 33 is rotationally driven while the outer peripheral surface is guided by the guide portion 72 (see FIG. 5). be able to.

As the container body 33 rotates, the spiral protrusions 331 spirally formed on the inner peripheral surface of the container body 33 allow the toner contained inside the container body 33 to flow along the longitudinal direction of the container body 33. It is conveyed from the bottom of the toner container 32 toward the drive output gear 81.

The conveyed toner is discharged from the toner container 32 and supplied into the hopper section 61 of the toner replenishment section 60. That is, the drive motor 91 appropriately rotates and drives the container body 33 of the toner container 32, so that the toner is appropriately supplied to the hopper portion 61. Each of the toner containers 32 (Y, M, C, K) of each color is replaced with a new one when it reaches the end of its life, for example, when almost all the toner contained is consumed and emptied.

As shown in FIG. 3, the toner replenishment unit 60 includes a hopper unit 61, a toner transfer screw 62, and a drive motor 91. The toner supplied from the toner container 32 is stored in the hopper portion 61, and a toner transport screw 62 is provided.

When the control unit detects that the toner concentration in the developing unit 5 has decreased based on the detection result of the toner concentration detection sensor 56 (see FIG. 2), the toner replenishing unit 60 rotates the toner transfer screw 62 for a predetermined time. Toner is replenished to the developing unit 5Y. Since the toner transfer screw 62 is rotated to replenish the toner, the amount of toner supplied to the developing unit 5 can be calculated accurately by detecting the rotation speed of the toner transfer screw 62.

A toner end sensor for detecting that the amount of toner stored in the hopper 61 is less than a predetermined amount is installed on the wall surface of the hopper 61. As the toner end sensor, a piezoelectric sensor or the like can be used. When the toner end sensor detects that the amount of toner stored in the hopper 61 is less than a predetermined amount (toner end detection), the drive motor 91 is driven. Then, the container body 33 of the toner container 32 is rotationally driven for a predetermined time to replenish the toner portion 61 with toner.

In the embodiment, the hopper unit 61 is provided to temporarily store the toner discharged from the toner container 32, but the toner discharged from the toner container 32 may be directly supplied to the developing unit 5.

Further, a temperature sensor 160 is provided on the lower wall surface 68 in the vicinity of the parallel plate electrode 66. The temperature sensor 160 is a sensor that detects the ambient temperature of the toner container 32 and outputs it to the control unit 250. The installation position of the temperature sensor 160 is not limited to the lower wall surface 68, and may be any position as long as the ambient temperature of the toner container 32 can be detected. If the relationship with the temperature in the vicinity of the parallel plate electrode 66 is known in advance, the temperature sensor 160 is installed in a place other than the vicinity of the parallel plate electrode 66, and the temperature is predicted from the temperature detected by the temperature sensor 160. The predicted value of the temperature in the vicinity of the parallel plate electrode 66 to be formed may be input to the control unit 250.

<Configuration example of toner remaining amount detecting device 200>
In the embodiment, as shown in FIGS. 3 and 4, the toner container 32 is sandwiched between the parallel plate electrodes 65 and 66 from the outside of the toner container 32, and the parallel plate electrodes 65 and 66 cover almost the entire toner container 32. I am trying to do it. Specifically, the length of the parallel plate electrodes 65 and 66 in the lateral direction is longer than the length of the diameter of the toner container 32, and the length of the parallel plate electrodes 65 and 66 in the longitudinal direction is the length of the toner container 32. It is more than half the length.

The parallel plate electrode 65 is fixed to the upper wall surface 67 of the image forming apparatus 100 facing the toner container 32 from above the toner container 32 with double-sided tape or the like. Further, the parallel plate electrode 66 is fixed to the lower wall surface 68 of the image forming apparatus 100 facing the toner container 32 from below the toner container 32 with double-sided tape or the like. The parallel plate electrodes 65 and 66 may be any conductive member, and in the embodiment, they are iron plates.

The parallel plate electrodes 65 and 66 have the same size. By making the parallel plate electrodes 65 and 66 the same size, it is possible to suppress variations in the density of electric lines of force between the parallel plate electrodes, and due to the uneven distribution of toner in the toner container 32, even if the amount of toner is the same. It is possible to suppress the difference in capacitance.

As shown in FIG. 3, the toner remaining amount detecting device 200 according to the embodiment includes parallel plate electrodes 65 and 66, a capacitance detecting circuit 111, and a control unit 250.

The parallel plate electrodes 65 and 66 are electrically connected to the capacitance detection circuit 111, respectively. By applying electric power from the capacitance detection circuit 111 to the pair of parallel plate electrodes 65 and 66, the capacitance between the parallel plate electrodes is detected.

The capacitance detection method may be a general method, and in the embodiment, a charging method (a constant voltage or a constant current is applied between the electrodes, and the capacitance is detected from the relationship between the time of the charging arrival point and the voltage or current. ) Detects the capacitance. The capacitance detection circuit 111 outputs a signal indicating the detected capacitance value to the control unit 250.

The detected capacitance changes depending on the dielectric constant between the parallel plate electrodes 65 and 66. Since toner has a higher dielectric constant than air, the dielectric constant changes depending on the amount of toner in the range of the electric field between the parallel plate electrodes. Therefore, the capacitance changes depending on the remaining amount of toner in the toner container 32 sandwiched between the parallel plate electrodes 65 and 66 from the outside.

Therefore, the control unit 250 refers to a predetermined calibration curve showing the relationship between the capacitance and the remaining amount of toner based on the capacitance detected by the capacitance detection circuit 111, and the toner residue in the toner container 32. The amount can be detected. The details of the functional configuration of the control unit 250 will be described later.

Here, FIG. 6 is a diagram illustrating an example of a calibration curve. The horizontal axis of FIG. 6 shows the remaining amount of toner, and the vertical axis shows the capacitance. When the toner remaining amount detecting device 200 generates the calibration curve 201, the capacitance C1 when the toner container 32 is empty, that is, when the remaining amount of toner in the toner container 32 is zero, and the toner container 32 are full. The capacitance C2 at the time is detected respectively. Then, by obtaining a linear equation including the capacitances C1 and C2 and associating the capacitance with the remaining amount of toner according to the linear equation, the calibration curve 201 can be generated in advance and stored in a memory or the like.

However, the state of the remaining amount of toner when the calibration curve 201 is generated is not limited to the time when the toner container 32 is empty and the state when the toner container 32 is full. The calibration curve 201 may be generated from the capacitance in a known state where the remaining amount of toner in the toner container 32 is 2 or more.

<Hardware configuration example of control unit 250>
Next, the hardware configuration of the control unit 250 included in the image forming apparatus 100 will be described. FIG. 7 is a block diagram illustrating an example of the hardware configuration of the control unit 250.

The control unit 250 includes a CPU (Central Processing Unit) 251, a ROM (Read Only Memory) 252, and a RAM (Random Access Memory) 253. Each is electrically connected to each other via a system bus (not shown).

The CPU 251 is a processor, controls the entire toner remaining amount detecting device 200, and comprehensively controls access to various devices connected to the system bus based on a control program or the like stored in the ROM 252. The CPU 251 can realize various functions described later by executing a control program stored in the ROM 252 with the RAM 253 as a work area.

The ROM 252 is a read-only non-volatile memory, and stores a control program, control data, and the like used by the CPU 251. Further, the ROM 252 stores information about the toner remaining amount detecting device 200 used by the control program.

The RAM 253 is a volatile memory capable of reading and writing information at high speed, and is used as a work frame memory used for expanding recorded data and storing environmental data.

The CPU 251 can exchange data with the operation panel 271 provided in the image forming apparatus 100. The operation panel 271 includes a display unit for displaying information, an input unit for receiving operations, and the like, and functions as a user interface. The CPU 251 displays the result detected by the capacitance detection circuit 111 on the operation panel 271, and also displays a toner ordering instruction and a toner replacement instruction under predetermined conditions.

The power supply 272 is an AC commercial power supply, and the power supply circuit 273 converts the AC voltage supplied from the power supply 272 into a DC voltage to supply power to each part of the image forming apparatus 100. The CPU 251 can control the power supply from the power supply circuit 273 to each part of the image forming apparatus 100.

Further, the CPU 251 can exchange signals and data with the capacitance detection circuit 111 to control the operation of the image forming unit 6.

The temperature sensor 160 as an example of the temperature detection unit is installed around the toner container 32 in the image forming apparatus 100, and detects the temperature around the toner container 32. The CPU 251 can input a signal indicating a temperature detection value by the temperature sensor 160 and use it for detecting the remaining amount of toner.

The various functions described later that are realized by the CPU 251 may be realized by an electronic circuit or an electric circuit such as an ASIC (application specific integrated circuit) or an FPGA (Field-Programmable Gate Array).

<Relationship between the ambient temperature of the toner container 32 and the detection error of the remaining amount of toner>
Here, in the capacitance method of detecting the remaining amount of toner based on the capacitance described with reference to FIG. 3 and the like, the ambient temperature of the toner container 32 may be affected.

For example, due to a change in the ambient temperature of the toner container 32, a member including the upper wall surface 67 to which the parallel plate electrode 65 is fixed and the lower wall surface 68 to which the parallel plate electrode 66 is fixed expands or contracts between the parallel plate electrodes 65 and 66. Distance changes. Due to this change in distance, the relationship between the capacitance and the remaining amount of toner may deviate from the relationship indicated by the calibration curve generated in advance, and accurate remaining amount of toner may not be detected.

In addition, since the capacitance changes according to the temperature dependence of the toner itself, the relationship between the capacitance and the remaining amount of toner deviates from the relationship indicated by the calibration curve, making it impossible to detect the remaining amount of toner accurately. In some cases.

FIG. 8 is a diagram illustrating an example of such a change in the calibration curve due to temperature. The calibration curve 202 shown by the alternate long and short dash line in FIG. 8 is when the ambient temperature of the toner container 32 is high, and the calibration curve 203 shown by the alternate long and short dash line 203 is when the ambient temperature of the toner container 32 is low. It is a thing.

As shown in FIG. 8, since the calibration curve 202 and the calibration curve 203 have different slopes, the difference in capacitance value according to the remaining amount of toner becomes large in proportion to the remaining amount of toner. The capacitance difference 210 in FIG. 8 indicates the difference in capacitance value when the remaining amount of toner is full.

The difference in capacitance value corresponds to the variation in detection of the remaining amount of toner by the capacitance method. As the temperature fluctuation increases and the deviation between the actual capacitance and the remaining amount of toner with respect to the calibration curve increases, the error in detecting the remaining amount of toner by the capacitance method increases.

On the other hand, as another detection method for the remaining amount of toner, a cumulative information method for predicting and detecting the remaining amount of toner based on information such as the cumulative driving time of the toner transport screw 62 and the cumulative image area formed on the recording medium can be considered.

More specifically, as a cumulative information method, a method in which an image area formed on a recording medium is represented by a pixel count, which is the result of counting the number of pixels, and the remaining amount of toner is predicted and detected based on the cumulative pixel count. And so on. With this method, the amount of toner used for the image formed on the recording medium (the amount of toner adhering to the photoconductor per image area is almost constant) can be calculated, so if the cumulative image area is known, the amount of toner consumed. You can see (usage). By subtracting the toner consumption from the reference value of the toner remaining amount such as the toner amount at the time of initial filling, the toner remaining amount can be predicted and detected.

However, in such a cumulative information method, as the toner is consumed and the cumulative information such as the cumulative image area increases, the prediction error of the remaining amount of toner accumulates and increases. Therefore, when the toner is consumed and the remaining amount of toner is low, the detection error of the remaining amount of toner may increase.

FIG. 9 is a diagram illustrating an example of a toner remaining amount detection error by each of the capacitance method and the cumulative information method.

The two graphs 93 shown by the alternate long and short dash line in FIG. 9 show the variation range of the toner remaining amount detection value by the capacitance method with respect to the actual toner remaining amount (toner actual remaining amount). As shown by the variation width 931 indicated by the arrow, the width sandwiched between the two graphs 93 corresponds to the variation width. As shown in FIG. 9, in the capacitance method, the larger the remaining amount of toner, the larger the variation (detection error) of the remaining amount of toner detection value.

On the other hand, the two graphs 94 shown by the alternate long and short dash lines in FIG. 9 show the variation width of the toner remaining amount detection value by the cumulative information method with respect to the actual toner remaining amount. As shown by the variation width 941 indicated by the arrow, the width sandwiched between the two graphs 94 corresponds to the variation width. As shown in FIG. 9, in the cumulative information method, the smaller the remaining amount of toner, the larger the detection error of the remaining amount of toner.

Therefore, in the embodiment, the cumulative information method and the capacitance method are combined, and when the ambient temperature of the toner container 32 is within a predetermined range, the remaining amount of toner is detected by the capacitance method, and the ambient temperature of the toner container 32 is adjusted. If it is not within the specified range, the remaining amount of toner is detected by the cumulative information method. This predetermined range is a temperature range predetermined by an experiment or a simulation as a temperature range in which the detection error of the remaining amount of toner by the capacitance method is small. In other words, this predetermined range is a temperature range in which a predetermined calibration curve is effective.

In the following, the toner remaining amount information detected by the capacitance method is referred to as the first toner remaining amount information, and the toner remaining amount information detected by the cumulative information method is referred to as the second toner remaining amount information.

<Example of functional configuration of control unit 250>
FIG. 10 is a block diagram showing an example of the functional configuration of the control unit 250 according to the first embodiment. As shown in FIG. 10, the control unit 250 includes a determination unit 261, a switching unit 262, an output unit 263, a calibration curve storage unit 264, a first toner remaining amount detection unit 265, and a pixel counting unit 266. A second toner remaining amount detecting unit 267 is provided.

Of these, the CPU 251 executes a predetermined program for the functions of the determination unit 261, the switching unit 262, the output unit 263, the first toner remaining amount detecting unit 265, the pixel counting unit 266, and the second toner remaining amount detecting unit 267. The function of the calibration curve storage unit 264 is realized by the ROM 252 and the like.

The determination unit 261 determines whether or not the ambient temperature of the toner container 32 input from the temperature sensor 160 is within a predetermined range, and outputs the determination result to the switching unit 262.

The switching unit 262 switches the toner remaining amount information to be output via the output unit 263 based on the determination result by the determination unit 261. Specifically, the switching unit 262 inputs the first toner remaining amount information detected by the first toner remaining amount detecting unit 265 at a predetermined sampling cycle, and the second toner remaining amount detecting unit 267 detects the second toner remaining amount information. Toner remaining amount information is input each time image formation is performed. Then, when the ambient temperature of the toner container 32 is within a predetermined range, the first toner remaining amount information is output to the notification unit 270 of the operation panel 271 via the output unit 263. On the other hand, when the ambient temperature of the toner container 32 is not within the predetermined range, the second toner remaining amount information is output to the notification unit 270 of the operation panel 271 via the output unit 263.

Further, the switching unit 262 also has a function of resetting the pixel counting unit 266 at the switching time when the ambient temperature of the toner container 32 is switched from the state where the ambient temperature is within the predetermined range to the state where the ambient temperature is not within the predetermined range. By this reset, the cumulative pixel count number by the pixel count unit 266 is initialized to 0.

The calibration curve storage unit 264 stores a predetermined calibration curve generated in advance when the ambient temperature of the toner container 32 is within a predetermined range.

The first toner remaining amount detection unit 265 is stored in the calibration curve storage unit 264 based on the detection value of the capacitance between the parallel plate electrodes 65 and 66 input from the capacitance detection circuit 111 at a predetermined sampling cycle. Detect the remaining amount of toner by referring to the calibration curve. Then, the first toner remaining amount information indicating the detected value of the toner remaining amount is output to the switching unit 262 and the second toner remaining amount detecting unit 267.

The pixel counting unit 266 counts the number of pixels constituting the image formed on the recording medium P when the image forming apparatus 100 executes image forming. This count of the number of pixels is performed every time an image is formed on the recording medium P, and the cumulative number of pixel counts is acquired. This cumulative pixel count number corresponds to the "cumulative value of the number of pixels" and is an example of "cumulative information".

Here, as described above, at the switching time when the ambient temperature of the toner container 32 is switched from the state where the ambient temperature is within the predetermined range to the state where the ambient temperature is not within the predetermined range, the cumulative pixel count number by the pixel counting unit 266 is determined by the switching unit 262. It will be reset. When reset, the pixel counting unit 266 starts counting from 0 in the initial state. The pixel counting unit 266 outputs the cumulative pixel count number to the second toner remaining amount detecting unit 267 each time the image is formed.

The second toner remaining amount detecting unit 267 predicts the toner consumption based on the cumulative pixel count number input from the pixel counting unit 266. Then, the remaining amount of toner is detected by subtracting the amount of toner consumed from the reference value of the remaining amount of toner in the toner container 32.

Here, when the toner container 32 is full, the remaining amount of full toner at the time of initial filling is set as the reference value of the remaining amount of toner. When the first toner remaining amount detecting unit 265 detects the remaining amount of toner, the remaining amount of toner indicated by the first remaining amount of toner information is set as a reference value of the remaining amount of toner.

After detecting the remaining amount of toner by the cumulative information method, the second toner remaining amount detecting unit 267 outputs the second toner remaining amount information indicating the detected value of the remaining amount of toner to the switching unit 262.

<Processing example by control unit 250>
Next, the processing by the control unit 250 will be described. FIG. 11 is a flowchart showing an example of processing by the control unit 250. Note that FIG. 11 shows the processing from the initial state in which the toner container 32 is fully filled with toner.

First, in step S111, the switching unit 262 resets the cumulative pixel count number of the pixel counting unit 266.

Subsequently, in step S112, the second toner remaining amount detecting unit 267 sets the reference value of the toner remaining amount to the toner remaining amount when the toner container 32 is full.

Subsequently, in step S113, the determination unit 261 inputs the detected value of the ambient temperature of the toner container 32 from the temperature sensor 160.

Subsequently, in step S114, the determination unit 261 determines whether or not the ambient temperature of the toner container 32 is within a predetermined range.

When it is determined in step S114 that the temperature is not within the predetermined range (step S114, No), in step S115, the switching unit 262 changes from the state where the ambient temperature of the toner container 32 is within the predetermined range to the state where it is not within the predetermined range. Determine if there was a switch.

If it is determined in step S115 that there is no switching (step S115, No), the process proceeds to step S117. On the other hand, when it is determined in step S115 that there is a change (step S115, Yes), in step S116, the switching unit 262 resets the cumulative pixel count number of the pixel counting unit 266.

Subsequently, in step S117, the second toner remaining amount detecting unit 267 predicts the toner consumption based on the cumulative pixel count number input from the pixel counting unit 266. Then, by subtracting the toner consumption amount from the reference value indicating the remaining amount of toner, the remaining amount of toner is detected, and the second remaining amount of toner information indicating the detected value is output to the switching unit 262. The switching unit 262 outputs the second toner remaining amount information to the notification unit 270 via the output unit 263.

Here, returning to step S114, when it is determined that the ambient temperature of the toner container 32 is within a predetermined range (step S114, Yes), in step S118, the first toner remaining amount detecting unit 265 has a capacitance. Based on the detected value of the capacitance between the parallel plate electrodes 65 and 66 input from the detection circuit 111 at a predetermined sampling cycle, the remaining amount of toner is detected with reference to the calibration curve stored in the calibration curve storage unit 264. Then, the first toner remaining amount information indicating the detected value is output to the switching unit 262 and the second toner remaining amount detecting unit 267. The switching unit 262 outputs the first toner remaining amount information to the notification unit 270 via the output unit 263.

Subsequently, in step S119, the second toner remaining amount detecting unit 267 sets the toner remaining amount indicated by the first toner remaining amount information input from the first toner remaining amount detecting unit 265 as the reference value of the toner remaining amount. ..

Subsequently, in step S120, the notification unit 270 determines whether or not the remaining amount of toner indicated by the first toner remaining amount information or the second toner remaining amount information is equal to or less than the amount required to replace the toner container 32. .. The amount of the toner container 32 that needs to be replaced is predetermined and stored in a memory such as ROM 252 in FIG. 7.

When it is determined in step S120 that the amount of the toner container 32 to be replaced is less than the required amount (step S120, Yes), the notification unit 270 displays a message on the operation panel 271 to replace the toner container 32. Notify the user of the image forming apparatus 100 that it is necessary.

On the other hand, if it is determined in step S120 that the amount of toner container 32 to be replaced is not less than the required amount (steps S120, No), the processes after step S113 are executed again.

In this way, the remaining amount of toner is detected, and when the remaining amount of toner becomes equal to or less than the amount required for replacement of the toner container 32, the user of the image forming apparatus 100 can be notified to that effect.

The processes of steps S111 and S112 in FIG. 11 may be rearranged in an appropriate order, or both may be executed in parallel. Similarly, the processes of steps S118 and S119 may be appropriately rearranged in order, or both may be executed in parallel.

[First Embodiment]
<About the detection accuracy of the toner remaining amount information according to the first embodiment>
Next, FIG. 12 is a diagram for explaining the detection accuracy of the remaining amount of toner according to the first embodiment. The horizontal axis of FIG. 12 shows the actual remaining amount of toner (actual remaining amount of toner), and the vertical axis shows the detected value of the remaining amount of toner.

Here, in the capacitance method, not only the detection error caused by the fluctuation of the ambient temperature of the toner container 32 but also the detection error caused by a factor other than the temperature fluctuation such as the voltage fluctuation error of the capacitance detection circuit 111 occurs. ..

The out-of-temperature error 121 shown in FIG. 12 indicates a detection error (variation width) of the remaining amount of toner by the capacitance method due to a factor other than the fluctuation of the ambient temperature of the toner container 32, and the temperature error 122 is the temperature error 122 of the toner container 32. It shows the detection error of the remaining amount of toner by the capacitance method due to the fluctuation of the ambient temperature. Further, the total error 123 indicates the sum of the out-of-temperature error 121 and the temperature error 122. As shown in FIG. 12, such an out-of-temperature error 121, a temperature error 122, and an overall error 123 become smaller as the actual remaining amount of toner decreases.

Of these, the temperature error 122 is allowed by detecting the remaining amount of toner by the capacitance method and outputting the information on the remaining amount of the first toner only when the ambient temperature of the toner container 32 is within a predetermined range. It is reduced below the range. As a result, the overall error 123 is suppressed, and only the out-of-temperature error 121 is obtained.

On the other hand, in the embodiment, when the ambient temperature of the toner container 32 is not within the predetermined range, the remaining amount of toner is detected by the cumulative information method. In the cumulative information method, the cumulative error increases as the toner consumption increases. The cumulative error 124 shown by the broken line in FIG. 12 indicates the cumulative error when the ambient temperature of the toner container 32 is switched from the state within the predetermined range to the state not within the predetermined range at a predetermined timing. Further, the cumulative error 125 indicates a cumulative error when the ambient temperature of the toner container 32 is switched from a state within the predetermined range to a state not within the predetermined range at a timing different from the above-mentioned predetermined timing.

If the toner remaining amount detection method is switched from the cumulative information method to the capacitance method before the cumulative error 124 or 125 becomes larger than the total error 123 in the capacitance method, the cumulative error 124 or 125 becomes the total error. The cumulative error can be cleared by resetting the cumulative information such as the cumulative pixel count number before it becomes larger than 123.

Therefore, the above as a condition for switching from the cumulative information method to the capacitance method so that the cumulative error such as the cumulative error 124 or 125 is switched from the cumulative information method to the capacitance method before the cumulative error becomes larger than the total error 123. It is preferable to determine a predetermined range.

<Action and effect of image forming apparatus 100>
As described above, the present embodiment includes the toner remaining amount detecting device 200 for detecting the remaining amount of toner in the toner container 32. In the toner remaining amount detecting device 200, when the ambient temperature of the toner container 32 is within a predetermined range, it is detected based on the capacitance value between the parallel plate electrodes 65 and 66 arranged so as to sandwich the toner container 32. Outputs the first toner remaining amount information indicating the toner remaining amount. On the other hand, when the ambient temperature of the toner container 32 is not within the predetermined range, the second toner remaining amount information indicating the remaining amount of toner detected based on the cumulative pixel count number is output.

As a result, the ambient temperature of the toner container 32 fluctuates by detecting the remaining amount of toner by the capacitance method only within the effective temperature range of a predetermined calibration curve showing the relationship between the capacitance value and the remaining amount of toner. It is possible to suppress the error caused by the above and detect the remaining amount of toner with high accuracy.

Further, in the present embodiment, the remaining amount of toner indicated by the second remaining amount of toner information is the remaining amount of the first toner at the time of switching from the state where the ambient temperature of the toner container 32 is within the predetermined range to the state where the ambient temperature is not within the predetermined range. It is detected by subtracting the toner consumption predicted based on the cumulative pixel count number calculated from the switching time from the remaining amount of toner indicated by the information.

By doing so, each time the ambient temperature of the toner container 32 is switched from the state where the ambient temperature is within the predetermined range to the state where the ambient temperature is not within the predetermined range, the second toner remaining amount information is generated by the toner remaining amount indicated by the first toner remaining amount information. The effect of calibrating the indicated toner level can be obtained. As a result, the cumulative error in the cumulative information method can be suppressed.

Further, in the present embodiment, the toner remaining amount detection method is switched from the cumulative information method to the capacitance method before the cumulative error 124 in the cumulative information method becomes larger than the overall error 123 in the capacitance method. A predetermined range with respect to the ambient temperature of the toner container 32 as a condition is determined. In other words, when the detection error by the cumulative information method is greater than or equal to the detection error by the capacitance method, the above-mentioned predetermined range as a switching condition is defined so that the output unit 263 outputs the first toner remaining amount information. ..

By doing so, the cumulative information such as the cumulative pixel count number can be reset before the cumulative error 124 becomes larger than the total error 123, the cumulative error can be removed, and the detection accuracy of the remaining amount of toner can be improved.

[Second Embodiment]
In the first embodiment, each time the ambient temperature of the toner container 32 is switched from the state where the ambient temperature is within the predetermined range to the state where the ambient temperature is not within the predetermined range, the second toner remaining amount information is indicated by the toner remaining amount indicated by the first toner remaining amount information. It was stated that the effect of calibrating the remaining amount of toner can be obtained.

However, the ambient temperature of the toner container 32 may not fall within the predetermined range even after a long period of time has passed. During the period in which the ambient temperature of the toner container 32 does not fall within the predetermined range, the effect of calibrating the remaining amount of toner indicated by the second remaining amount of toner information cannot be obtained.

Therefore, in the present embodiment, when the remaining amount of toner indicated by the second toner remaining amount information becomes less than the predetermined remaining amount, the switching unit 262 (see FIG. 10) outputs the toner via the output unit 263. The toner remaining amount information is switched from the second toner remaining amount information by the cumulative information method to the first toner remaining amount information by the capacitance method.

FIG. 13 is a diagram illustrating the detection accuracy of the remaining amount of toner according to the present embodiment. Since the portion overlapping with FIG. 12 is the same as that of FIG. 12, description thereof will be omitted.

In FIG. 13, the cumulative error 130 shown by the broken line indicates the cumulative error in the cumulative information method. Further, the section 131 is a section of the actual toner remaining amount in which the cumulative error 130 by the cumulative information method is smaller than the total error 123 by the capacitance method, and the section 132 is the section of the actual toner remaining amount in which the cumulative error 130 is larger than the total error 123. It is a section.

When switching from the section 131 to the section 132, the switching unit 262 changes the toner remaining amount information to be output via the output unit 263 from the second toner remaining amount information by the cumulative information method to the first toner remaining amount information by the capacitance method. Switch to. The actual amount of toner remaining when switching from section 131 to section 132 is determined in advance by an experiment, simulation, or the like as a predetermined remaining amount, and is stored in a memory such as ROM 252.

As described above, in the present embodiment, when the remaining amount of toner indicated by the second toner remaining amount information becomes less than the predetermined remaining amount, the switching unit 262 outputs the toner via the output unit 263. The remaining amount information is switched from the second toner remaining amount information by the cumulative information method to the first toner remaining amount information by the capacitance method. In other words, the output unit 263 outputs the first toner remaining amount information when the toner remaining amount indicated by the second toner remaining amount information becomes equal to or less than the predetermined remaining amount. As a result, the accuracy of detecting the remaining amount of toner can be improved even when the ambient temperature of the toner container 32 does not fall within the predetermined range even after a long period of time has passed.

If the ambient temperature of the toner container 32 falls within a predetermined range during detection by the capacitance method, the remaining amount of toner indicated by the second toner remaining amount information is equal to or less than the predetermined remaining amount. The method of switching the toner remaining amount information depending on whether or not it is performed may not be performed.

[Third Embodiment]
Due to the operation of the image forming apparatus 100, the ambient temperature of the toner container 32 may fluctuate abruptly. In the image forming apparatus 100, when the upper wall surface 67 (see FIG. 3) and the lower wall surface 68 for fixing the parallel plate electrode 65 are made of a material such as resin that is easily deformed by temperature, the image forming apparatus 100 expands or contracts due to a sudden temperature fluctuation. , It may take some time for these to converge (stable). As a result, even if the ambient temperature of the toner container 32 is within a predetermined range, the relationship between the capacitance and the remaining amount of toner deviates from the relationship indicated by the calibration curve generated in advance, and the detection accuracy of the remaining amount of toner is improved. May decrease.

Therefore, in the present embodiment, the relationship between the fluctuation amount of the ambient temperature of the toner container 32 and the convergence time of expansion or contraction is investigated in advance by an experiment or simulation, and a table showing this relationship is shown in ROM 252 (see FIG. 7) or the like. Store in the memory of.

The switching unit 262 (see FIG. 10) acquires the convergence time of expansion or contraction with reference to the above table based on the fluctuation amount of the ambient temperature of the toner container 32 detected by the temperature sensor 160. Then, after the convergence time has elapsed, the first toner remaining amount information input from the first toner remaining amount detecting unit 265 is output to the notification unit 270 via the output unit 263.

As a result, even when the ambient temperature of the toner container 32 fluctuates abruptly, the remaining amount of toner can be detected after the expansion or contraction has converged, so that it is possible to suppress a decrease in the detection accuracy of the remaining amount of toner.

Here, FIG. 14 is a diagram showing an example of a table showing the relationship between the amount of temperature fluctuation and the expansion convergence time.

The "parts" column shows the resin material A constituting the upper wall surface 67 and the resin member B constituting the lower wall surface 68. In the "temperature fluctuation amount" column and the "expansion convergence time" column, the fluctuation amount of the ambient temperature of the toner container 32 and the time for the expansion of the upper wall surface 67 and the lower wall surface 68 to converge are shown in association with each other. The numbers shown in the "Expansion Convergence Time" column correspond to the above convergence times.

Although the image forming apparatus according to the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the present invention.

Here, in the embodiment, a method using the cumulative number of pixels is shown as the cumulative information method, but the method is not limited to this. The cumulative drive time of the toner transport screw 62 can be used as cumulative information to predict and detect the remaining amount of toner.

Since the toner transfer amount of the toner transfer screw 62 is substantially proportional to the rotation angle (rotation time), the toner consumption can be known by recording the total rotation time of the toner transfer screw 62, and the initial filling amount of the toner container 32 can be used. By subtracting the toner consumption, the remaining amount of toner can be predicted and detected.

Further, in the embodiment, an example of displaying a message on the operation panel 271 is shown as a method of notifying the user that the toner container 32 needs to be replaced, but the present invention is not limited to this. A message indicating that the toner container 32 needs to be replaced is displayed on an external device such as a PC (Personal Computer) or a server managed by the user via a LAN (Local Area Network) or the Internet, or an email containing the message. May be sent.

The embodiment also includes a method for detecting the remaining amount of toner. For example, the toner remaining amount detecting method performs a detection step of detecting the temperature around the toner container and an output step of outputting the toner remaining amount information in the toner container, and in the output step, the temperature is predetermined. When it is within the range, the first toner remaining amount information detected based on the capacitance value between the plurality of electrodes arranged across the toner container is output, and when the temperature is not within the predetermined temperature range, The second toner remaining amount information detected based on the cumulative information of image formation is output. By such a toner remaining amount detecting method, the same effect as the above-mentioned toner remaining amount detecting apparatus can be obtained.

32 Toner container 65, 66 Parallel plate electrode (example of multiple electrodes)
100 Image forming device 111 Capacitance detection circuit 160 Temperature sensor (an example of temperature detection unit)
200 Toner remaining amount detection device 250 Control unit 261 Judgment unit 262 Switching unit 263 Output unit 264 Calibration curve storage unit 265 First toner remaining amount detection unit 266 Pixel counting unit 267 Second toner remaining amount detection unit 270 Notification unit 271 Operation panel P recoding media

JP-A-2007-121620

Claims (7)

A temperature detector that detects the ambient temperature of the toner container,
A plurality of electrodes arranged across the toner container,
An output unit that outputs information on the remaining amount of toner in the toner container is provided.
The output unit outputs first toner remaining amount information detected based on the capacitance value between the plurality of electrodes when the temperature is within a predetermined range, and an image when the temperature is not within the predetermined temperature range. An image forming apparatus that outputs information on the remaining amount of the second toner detected based on the cumulative information of formation. The second toner remaining amount information detected by the output unit with reference to a predetermined calibration curve showing the relationship between the capacitance value and the toner remaining amount within the predetermined range based on the capacitance value. The image forming apparatus according to claim 1. The image forming apparatus according to claim 1 or 2, wherein the cumulative information is a cumulative value of the number of pixels in an image formed on a recording medium. The second toner remaining amount information is the switching from the toner remaining amount detected based on the capacitance value at the time of switching from the state where the temperature is within the predetermined range to the state where the temperature is not within the predetermined range. The image forming apparatus according to any one of claims 1 to 3, which is obtained by subtracting the amount of toner consumed detected based on the cumulative information calculated from the time period. The output unit according to any one of claims 1 to 4 for outputting the first toner remaining amount information when the toner remaining amount indicated by the second toner remaining amount information becomes equal to or less than a predetermined remaining amount. The image forming apparatus according to the description. A storage unit for storing the relationship between the amount of temperature fluctuation and the convergence time at which the distance fluctuation between the plurality of electrodes converges is provided.
The item according to any one of claims 1 to 5, wherein the output unit outputs the toner remaining amount information after the convergence time detected by referring to the storage unit based on the fluctuation amount of the temperature has elapsed. Image forming device. A detection process that detects the ambient temperature of the toner container,
The output step of outputting the toner remaining amount information in the toner container is performed.
In the output step, when the temperature is within a predetermined range, the first toner remaining amount information detected based on the capacitance value between a plurality of electrodes arranged across the toner container is output, and the temperature is described. A toner remaining amount detection method that outputs second toner remaining amount information detected based on cumulative information of image formation when is not within a predetermined temperature range.

Images