JP6570862B2 - Toner amount determination method and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet using toner, and more particularly to a toner amount determination method for detecting a remaining amount of toner in a developing device provided in the image forming apparatus.

  In an image forming apparatus that uses toner as a developer, the toner in the developing apparatus is consumed each time an image is formed. For this reason, when the toner is consumed by image formation and the remaining amount of toner in the developing device is reduced to a predetermined value or less, a mechanism is provided that detects the toner out and signals the user to replenish the toner.

  As a method for detecting the toner out, a method may be considered in which a toner sensor is used in the developing container and the toner out is detected based on an output value output from the sensor. For example, when the toner is a magnetic toner, a magnetic permeability sensor is used as the toner sensor. If the toner is present on the detection surface of the sensor, ON output is performed. If the toner is not present on the detection surface, OFF output is performed. Of the predetermined number of outputs within a predetermined time (for example, the time during which the stirring and conveying member in the developing device makes one round), the number of ON outputs is calculated as one block output value. Then, when this 1-block output value becomes equal to or less than the threshold value, toner out is detected.

However, in the configuration in which the toner in the developing container is agitated and conveyed by the agitating member, since the toner surface changes greatly due to agitation, the detection accuracy varies when the toner remaining amount is detected by the toner sensor. For example, as shown in FIG. 8, when the toner 101 in the developing container 100 is agitated by the agitating member 102 and the presence or absence of toner is detected by the toner sensor 103, the toner agent surface changes so much as shown in FIG. If not, the toner sensor 103 accurately turns ON. However, when the toner is biased to one side in the container by stirring as shown in FIG. 8B, the output is turned OFF regardless of the presence of the toner in the developing container. As shown in FIG. 8 (c) Conversely, if the toner adheres to the vicinity of the toner sensor 103 can cause becomes erroneous detection and ON despite no remaining toner in the developing container output.

  In order to prevent this, in Patent Document 1, one block output value is detected a plurality of times, a moving average value of the plurality of one block output values is calculated, and whether or not this moving average value falls below a threshold for toner exhaustion determination. However, a method for detecting out of toner has been proposed. The moving average value is a value obtained by shifting the average value for each certain interval in the time series data while shifting the interval. Here, for example, a 10-point moving average value indicates an average value of the latest 10 one-block output values. According to this method, even when noise is included in one block output value, in order to detect toner out from the average value of a plurality of one block output values, the number of one block output values to be averaged is increased. For example, noise can be cut to some extent from the result of toner out detection.

JP2012-168433

  However, as described above, since the agitated toner agent surface changes, a false detection value (noise) is entered. In order to alleviate the influence of noise that suddenly enters, it is necessary to obtain a large number of detection results for obtaining an average value.

  Here, a result of an endurance experiment using the developing device having the configuration shown in FIG. 8 in order to accurately determine toner out without the influence of noise is shown. The apparatus used in the experiment is an apparatus that does not have toner when an image of approximately 34,000 sheets is formed. The toner sensor 103 detects the presence or absence of toner 63 times at regular intervals while the stirring member 102 rotates once. . In this experiment, the number of detections during one rotation of the stirring member 102 is one block, and when the number of detections with toner per block is 15 or less, it is determined that the toner has run out.

  FIG. 9A shows a case where it is determined that the toner has run out when the output value of one block is 15 times or less in the toner presence / absence detection without taking the average value of a plurality of blocks. In this case, when the image formation was about 28,000 sheets, a noise was generated indicating that the presence of toner was 15 times or less, and it was determined that the toner was exhausted at that time. However, much toner remained in the developing container.

  FIG. 9B shows a case where determination is made based on an average value of 1 block output values for 20 blocks. With the average value of 20 points, noise for detecting the presence or absence of toner could not be cut, and it was determined that the toner was out due to noise generated at about 28,000 sheets.

  FIG. 9C shows a case where the number of detected blocks is further increased and determination is made based on an average value of 1 block output values for 40 blocks. When the average of 40 points was reached, the toner presence / absence detection noise could be cut, and it was determined that the toner was out of about 34,000 sheets.

  As described above, when toner out is determined based on the average value of the detection results for a plurality of blocks, it is necessary to obtain a large number of detection results in order to accurately determine without the influence of noise. However, in this case, since the average value of many 1-block output values is used, noise is alleviated and at the same time the latest 1-block output value is also alleviated. Accordingly, it is difficult for the latest toner remaining amount in the developing device to be reflected in the result of toner out detection. In this case, when the toner out should be detected, the toner out cannot be detected. If the image is formed as it is, there is a possibility of causing an image defect such as white spot.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a toner amount determination method capable of accurately and quickly detecting toner out even when there is noise in toner detection, and an image forming apparatus capable of determining toner out by this. It is.

In order to achieve the above object, a typical configuration according to the present invention obtains the detection result of the toner amount in the developing container by the toner detection means as an output value, and determines by a moving average of a predetermined number of the output values. A determination method for determining a toner amount in the developing container based on a value, an output value acquisition step of acquiring a latest output value of the toner detection unit, and a method of obtaining the latest output value and the determination value When the difference is smaller than the threshold value, the moving average of the output value updated using the latest output value is set as a new determination value, and when the difference is equal to or larger than the threshold value, the latest output value is replaced. A determination value update step in which the moving average of the output values updated using the determination value is a new determination value; a toner amount determination step in which the toner amount in the developing container is determined based on the new determination value; Features including To.

  In the present invention, even if there is noise in toner detection, it is possible to accurately determine whether the toner in the developing container has run out without delay.

1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. 1 is a block diagram illustrating a system configuration of a developing device according to a first embodiment of the present invention. 1 is a schematic cross-sectional view of a developing device according to a first embodiment of the present invention. 6 is a flowchart when the toner-out detection method according to the first embodiment of the present invention is performed. 6 is a graph showing an execution result of a toner out detection method according to the first embodiment of the present invention. 7 is a flowchart when a toner out detection method according to a second embodiment of the present invention is performed. 6 is a graph showing an execution result of a toner out detection method according to a second embodiment of the present invention. It is a figure explaining a prior art. It is a figure which shows the implementation result at the time of prior art implementation.

[First Embodiment]
<Image forming apparatus>
Hereinafter, the overall configuration of the image forming apparatus A according to the first embodiment of the present invention will be described with reference to the drawings together with the operation during image formation.

  As shown in FIG. 1, the image forming apparatus A includes an image forming unit that transfers a toner image to a sheet, a sheet feeding unit that supplies the sheet to the image forming unit, and a fixing unit that fixes the toner image on the sheet. Prepare.

  The image forming unit includes a photosensitive drum 1 (image carrier), a charging roller 2, a laser scanner unit 3, a developing device 4, a transfer roller 5 (transfer means), a cleaning blade 7, and the like.

  In image formation, when the CPU 201 (control unit) shown in FIG. 2 issues a print signal, the sheets stacked and stored in the sheet stacking unit 10 by the feeding roller 9 and the conveying roller 8 are sent out to the image forming unit.

  On the other hand, in the image forming unit, a charging bias is applied to the charging roller 2 from a high-voltage power supply (not shown), so that the surface of the photosensitive drum 1 in contact with the charging roller 2 is charged. The laser scanner unit 3 emits laser light from a light source (not shown) provided therein, and irradiates the photosensitive drum 1 with the laser light. As a result, the potential of the photosensitive drum 1 is partially reduced, and an electrostatic latent image corresponding to image information is formed on the surface of the photosensitive drum 1.

  Thereafter, a developing bias is applied to the developing sleeve 15 provided in the developing device 4, whereby toner is attached to the electrostatic latent image formed on the surface of the photosensitive drum 1 from the developing sleeve 15 to form a toner image. The toner image formed on the surface of the photosensitive drum 1 is sent to a transfer nip portion formed between the photosensitive drum 1 and the transfer roller 5. When the toner image arrives at the transfer nip portion, a transfer bias having a polarity opposite to that of the toner is applied to the transfer roller 5, and the toner image is transferred to the sheet.

  Thereafter, the sheet onto which the toner image has been transferred is sent to the fixing device 11 where it is heated and pressurized to fix the toner image on the sheet. Thereafter, the sheet is conveyed by the discharge roller 12 and discharged to the discharge unit.

<Developing device>
Next, the overall configuration and basic operation of the developing device 4 will be described. In addition, the configuration of the control unit of the control unit of the image forming apparatus A that is particularly related to the control at the time of toner out detection in the developing device 4 will be described.

  As shown in FIG. 3, the developing device 4 includes a developing sleeve 15 for forming a toner image on the surface of the photosensitive drum 1 during development, and a developing blade 16 that regulates a toner layer formed on the surface of the developing sleeve 15. . Further, the image forming apparatus includes a developing container 13 that contains toner used for development, a toner bottle 14 that contains toner to be replenished to the developing container 13, and a toner conveying member 17 that conveys toner from the developing container 13 to the developing sleeve 15.

  Inside the developing container 13 is provided a rotatable stirring member 18 that stirs and conveys the toner to the toner conveying member 17 while stirring the toner. In addition, a supply member 19 that supplies and conveys the toner to the developing container 13 while stirring the toner is provided inside the toner bottle 14.

  In addition, a toner sensor 204 (toner detection unit) that performs output according to the remaining amount of toner in the developing device 4 is provided inside the developing container 13. The toner sensor 204 will be described as a magnetic permeability sensor in the present embodiment. However, the present invention is not limited to this, and any other type of sensor such as an optical sensor may be used as long as the sensor performs output according to the remaining amount of toner. In this embodiment, the output method will be described as an ON / OFF output format that outputs ON when the toner is near a predetermined detection surface of the sensor, and outputs OFF when the toner near the detection surface is less than a predetermined value. However, the present invention is not limited to this, and an analog output method may be used.

  As shown in FIG. 2, the control unit 6 includes a CPU 201, a memory 202, and a calculation unit 203, and a display unit 206, a stirring motor 207, a toner sensor 204, and a toner out determination unit 205 are connected to the control unit 6.

  When toner out is detected, the control unit 6 selects the output value output from the toner sensor 204 by the CPU 201 and stores it in the memory 202. The toner out determination unit 205 determines toner out in the developing device 4 based on the output value stored in the memory 202. When it is determined that the toner is out, the CPU 201 displays the toner out on the display unit 206.

<Toner amount determination method>
Next, a method for determining toner out by determining the amount of toner in the developing device 4 will be described in detail.

  As described above, when toner out is detected by a magnetic permeability sensor or the like, the output value of the sensor varies depending on the state of the toner surface in the developing container at the time of output of the sensor. For this reason, noise due to erroneous detection is included in the output value, and the accuracy of the result of toner out detection may vary.

  In the toner out determination method according to the present embodiment, when calculating the toner out determination value, it is determined whether there is noise from the result of toner out detection, and the determination value without noise is calculated to calculate the toner in the developing device 4. This is to detect the cut accurately. Hereinafter, the determination method will be described with specific examples.

  In the present embodiment, the toner sensor 204 detects the presence or absence of toner in synchronization with the rotation of the stirring member 18. The toner sensor 204 detects toner at intervals of 10 msec, and performs toner detection 63 times while the stirring member 18 rotates once. In other words, one block is a period during which the stirring member 18 rotates once, and toner detection is continuously performed 63 times per block. And the control part 6 calculates the frequency | count of ON output among 63 detections as 1 block output value (ON output frequency / 63). The one block output value is stored in the memory 202 in time series. After that, among the plurality of 1-block output values stored in the memory 202, an average value of 1-block output values other than the 1-block output value determined as noise by a method described later is calculated, and the average value is a threshold value. When it becomes 15/63 or less, the toner-out determination unit 205 performs toner-out determination. That is, out of 63 detections during one rotation of the stirring member 18, it is determined that the toner has run out when the average number of ON outputs (detection of toner) becomes 15 or less.

  When toner out is detected, as shown in the flowchart of FIG. 4, the control unit 6 first confirms whether or not the developing device 4 is in a driving state (S1). I do.

  When the developing device 4 is in the driving state, first, it is confirmed whether or not the toner exhaustion determination value calculated from the toner exhaustion determination data is stored in the memory 202 (S2). The toner out determination data includes, in a time series, one block output value other than one block output value determined as noise by a method to be described later in time among the one block output values calculated from the output value output from the toner sensor 204. I remembered it. The average value of the 1-block output values stored in this time series is the toner out determination value.

  Next, when the toner out determination value is not stored in the memory 202, first, one block output value is detected a plurality of times in order to form toner out determination data (S3). Thereafter, the arithmetic unit 203 calculates an average value from the plurality of 1-block output values, and stores the calculated value in the memory 202 as a toner exhaustion determination value (S4). In this embodiment, one block output value is detected 10 times to form toner out determination data.

  Next, the latest one block output value is detected and stored in the memory 202 according to the output of the toner sensor 204 (S5). Next, an absolute value of a difference value between the latest one block output value and the toner exhaustion determination value is calculated (S6).

  If the toner out determination value is already stored in the memory 202 in step S2, it is not necessary to store the toner out determination value again. Therefore, in this case, steps S3 and S4 are not performed, the latest one block output value is detected (S5), and the absolute value of the difference value between the latest one block output value and the toner exhaustion determination value is calculated ( S6).

  Here, when the absolute value of the difference value between the latest one block output value and the toner exhaustion determination value (hereinafter simply referred to as the first difference value) is large, the latest one block output value is the toner in the developing device 4. It means that the remaining amount has changed abruptly. In this case, the latest one block output value is likely to be noise. Accordingly, as the next step, it is determined whether or not the first difference value is greater than or equal to a threshold value (S7). In the present embodiment, this threshold value is 5/63. For example, when the output average value so far is 18/63, the latest block output value is 10/63. In this case, the first difference value between the two is 8/63, which is a change equal to or greater than the threshold value. Thus, by comparing the latest block output value with the output average value so far, it is determined whether or not the latest detection result is noise.

  When the first difference value is smaller than the threshold value 5/63, this latest one-block output value means that the remaining amount of toner in the developing device 4 has changed gradually. For this reason, there is a high possibility that this latest one-block output value is not a noise but a correct value. Therefore, in this case, the latest one-block output value (detection value) Ra is added to the toner out determination data, the average value is calculated, and the toner out determination data An is updated (S8). Then, the updated toner out determination data An is stored in the memory 202 (S10).

  Here, as the toner exhaustion determination value, it is also possible to calculate and use an average value of all detected one block output values. However, in that case, the number of data for calculating the average value increases. Therefore, it is preferable to calculate the average value of the most recent predetermined number of 1-block output values. As a result, the number of 1-block output values to be averaged when calculating the toner out determination value is reduced, and the latest toner remaining amount in the developing device 4 is the result of the toner out determination value and the toner out detection result. It becomes easy to be reflected.

  Further, it is more preferable to use a moving average value as the average value of the most recent predetermined number of 1-block output values. This is because the latest toner remaining amount in the developing device 4 is easily updated and reflected in the toner out determination value and the result of toner out detection.

  On the other hand, when the first difference value is 5/63 or more of the threshold value, the latest one block output value is likely to be noise as described above. Therefore, if this latest one-block output value is added to the toner out determination data, noise is reflected in the result of toner out detection.

  Therefore, the toner out detection method according to the present embodiment does not add the latest one block output value Ra to the toner out determination data when the first difference value is 5/63 or more of the threshold value. Instead, the toner out determination value (detected average value An, which is an average value of one block output value of a predetermined block before the latest block) at that time is newly set as the latest one block output value in the toner out determination data. In addition, an average value of predetermined blocks including the latest block is set (S9). Then, the value is stored in the memory as an updated toner out determination value An (S10).

  When it is determined that the latest one block output value is noise, the toner out determination value (detected average value An) at that time is replaced with the latest one block output value as described above, and new toner out determination data is obtained. In addition, it is also possible to simply delete the latest one block output value. However, the toner-out determination value is calculated from the average value of the one-block output values stored in the toner-out determination data, and toner-out determination is performed based on this toner-out determination value. For this reason, in order to more accurately reflect the remaining amount of toner in the developing device 4 in the toner out detection result, the toner out determination value at that time is replaced with the latest one block output value for toner out determination. It is preferable to add new data.

  Next, it is determined whether or not the toner out determination value for which the average value is newly calculated by adding the latest one block output value is equal to or less than 15/63, which is the threshold for toner out determination (S11). Here, when the toner out determination value is 15/63 or less which is the threshold value, the toner out determination unit 205 determines the toner out and transmits this information to the determination control unit 6 (S12). Thereafter, the developing device 4 is stopped, and the display of the toner out is displayed on the display unit 206 (S13).

  On the other hand, when the toner-out determination value is higher than 15/63, which is the threshold value for toner-out determination, it is determined that the toner-out state has not occurred, and the developing device 4 newly performs the toner-out detection operation from step S1.

  As described above, in this embodiment, the average value of 1 block output values of predetermined blocks including the latest block is used as the toner exhaustion determination value. Then, the average value of the block output value Ra of the latest block is compared with the average value (detected average value) of one block output value of a predetermined block before the latest block. As the output value of the latest block, an average value calculated using the detected average value instead of the value Ra is used. As a result, it is possible to remove the detection noise and accurately determine toner out.

  FIG. 5 shows a result of detecting the toner out in the developing device 4 by the above-described experimental apparatus by the toner out determination method of the present embodiment. In this graph, the vertical axis represents the toner out determination value, and the horizontal axis represents the number of images formed by the image forming apparatus A. As shown in this graph, as a result of detecting the toner out by the above method, it is possible to almost eliminate the noise from the detection result, and it is accurately determined that the toner is out of the set image formation of about 34,000 sheets. .

[Second Embodiment]
Next, a second embodiment of the image forming apparatus A that performs toner exhaustion determination using the toner amount determination method according to the present invention will be described with reference to the drawings. The same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  In the first embodiment, whether or not the latest one block output value is noise is determined from the absolute value of the difference value between the toner exhaustion determination value and the latest one block output value. On the other hand, in the toner out detection method according to the present embodiment, noise determination data is stored in addition to the toner out determination data, and the noise determination value calculated from the noise determination data and the latest one block output value are stored. It is determined from the difference value whether the latest one block output value is noise. Here, the noise determination value is an average value of 1 block output values in a predetermined block which is continuous regardless of whether the 1 block output value is noise or not.

  In this toner out detection method, as shown in the flowchart of FIG. 6, the control unit 6 first checks whether or not the developing device 4 is in a driving state (S101), and performs the following control when in the driving state. .

  When the developing device 4 is in the driving state, first, it is confirmed whether or not the noise determination value An calculated from the noise determination data is stored in the memory 202 (S102). The noise determination data may be stored in chronological order for all one block output values calculated from the output values output from the toner sensor 204, but in the present embodiment, the noise determination data are output values of the past 10 blocks. The moving average value of 10 blocks of 1 block output value stored in time series is a noise judgment value (average value of output values output by the output means).

  Next, when the noise determination value is not stored in the memory 202, first, in order to form noise determination data, one block output value is detected a plurality of times (S103). Thereafter, the arithmetic unit 203 calculates an average value from the plurality of one-block output values, and stores the calculated value in the memory 202 as a noise determination value (S104). In the present embodiment, one block output value is continuously detected 10 times to form noise determination data.

  Next, the latest one-block output value Ra is detected and stored in the memory 202 according to the output of the toner sensor 204 (S105). Next, an absolute value of a difference value between the latest one block output value Ra and the noise determination value is calculated (S106).

  When the noise determination value has already been stored in the memory 202 in step S102, it is not necessary to store the noise determination value again. Therefore, in this case, steps S103 and S104 are not performed, the latest one block output value is detected (S105), and the absolute value of the difference value between the latest one block output value and the noise determination value is calculated (S106). ).

  When the absolute value of the difference value between the latest one-block output value Ra and the noise determination value (hereinafter simply referred to as the second difference value) is large, the latest one-block output value is the remaining toner amount in the developing device 4. Means a sudden change. In this case, the latest one block output value is likely to be noise. Therefore, as the next step, it is determined whether or not the second difference value is 5/63 or more which is a threshold value (S107). Thus, it can be determined whether or not the latest one block output value is noise.

  Here, there is the following advantage by determining the noise from the absolute value of the difference value between the noise determination value and the latest one block output value instead of the toner out determination value. That is, the out-of-toner determination value is an average value of 1 block output values other than the 1 block output value determined as noise among the detected 1 block output values. The determination as to whether or not the noise is present is based on the difference between the toner-out determination value at the time of the determination and the latest one block output value, and it is determined that the remaining amount of toner in the developing container 13 has changed abruptly. In this case, the latest one block output value is uniformly determined as noise.

  Accordingly, when noise is determined from the absolute value of the difference value between the toner exhaustion determination value and the latest one block output value, when the latest one block output value is determined to be noise, for example, it is an aspect of the toner agent surface. Even if the toner is actually consumed abruptly and the remaining amount of toner changes abruptly, it is determined as noise. In this case, since the toner continues to be consumed thereafter, the absolute value of the difference value between the toner out determination value and the latest one block output value continues to increase. If it does so, all the newest 1 block output values after that will be judged as noise.

  On the other hand, as described above, the noise determination value is an average value of the one block output value in the continuous predetermined block regardless of whether or not the one block output value is noise. If it changes, it will change accordingly. Therefore, when noise is determined from the difference value between the noise determination value and the latest one block output value, there is an inconvenience as in the case of determining noise from the difference value between the toner out determination value and the latest one block output value. There is an advantage that can be prevented.

  Next, when the second difference value is smaller than the threshold value 5/63, this latest one-block output value means that the toner remaining amount in the developing device 4 has changed gradually. For this reason, there is a high possibility that this latest one-block output value is not a noise but a correct value. Accordingly, in this case, the latest one-block output value is added to the toner out determination data (S108). It should be noted that since all the detected 1-block output values are added to the noise determination data, this latest 1-block output value is naturally added to the noise determination data.

  On the other hand, when the difference value is 5/63 or more of the threshold value, the latest one block output value is likely to be noise. Therefore, if this latest one-block output value is added to the toner out determination data, noise is reflected in the result of toner out detection.

  Therefore, the toner out detection method according to the present embodiment does not add the latest one block output value to the toner out determination data when the second difference value is 5/63 or more of the threshold value. Instead, the noise determination value at that time is newly added to the toner out determination data as the latest one block output value (S109). Since the detected 1-block output value is added to the noise determination data, the latest 1-block output value that is noise is also added to the noise determination data.

  Next, an average value is calculated using the noise determination data to which the latest one block output value is added (S110), and updated as new noise determination data.

  It is also possible to simply delete the latest one block output value determined as noise. However, the toner-out determination value is calculated from the average value of the one-block output values stored in the toner-out determination data, and toner-out determination is performed based on this toner-out determination value. For this reason, in order to more accurately reflect the remaining amount of toner in the developing device 4 in the toner out detection result, the noise determination value at that time is replaced with the latest one block output value, and the toner out determination data. It is preferable to add a new one.

  Next, it is determined whether a predetermined number or more of one block average value is stored in the toner out determination data (S111). In the present embodiment, the predetermined number of blocks is 10. Here, if the one-block output value of 10 blocks or more is not stored in the toner-out determination data, in order to further store the one-block output value in the toner-out determination data, the same operation is performed again by returning to step 101 above. Do.

  On the other hand, when one block output value of 10 blocks or more is recorded in the toner out determination data, an average value of a plurality of one block output values stored in the toner out determination data is calculated and updated, and a new one is output. The toner out determination value is stored in the memory 202 (S112).

  Here, as the toner out determination value, it is also possible to calculate an average value of all the one block output values in the toner out determination data. However, it is preferable to calculate the average value of the most recent predetermined number of 1-block output values. Thus, since the number of 1-block output values to be averaged when calculating the toner out determination value is small, the latest toner remaining amount status in the developing device 4 is reflected in the toner out determination value and the result of toner out detection. Cheap.

  Further, as in the case of the first embodiment, it is more preferable to calculate the moving average value as the average value of the most recent predetermined number of 1-block output values. This is because the latest toner remaining amount in the developing device 4 is easily reflected in the toner out determination value and the result of toner out detection.

  Next, it is determined whether or not the newly calculated toner out determination value Bn is equal to or less than 15/63 which is a toner out determination threshold (S113). Here, when the toner out determination value is 15/63 or less, which is the threshold value, the toner out determination unit 205 determines that the toner is out, and transmits this information to the control unit 6 (S114). Thereafter, the developing device 4 is stopped, and the display of the toner out is displayed on the display unit 206 (S115).

  On the other hand, when the toner out determination value is higher than the toner out determination threshold value 15/63, it is not in the toner out state, so that the developing device 4 newly starts the above step 101 to perform the toner out detection operation again. .

  In the present embodiment, an average value of one block output value of a predetermined block including the latest block is used as the toner exhaustion determination value. Then, the average value of the block output value Ra of the latest block is compared with the average value (detected average value) of one block output value of a predetermined block before the latest block. As the output value of the latest block, an average value calculated using the detected average value instead of the value Ra is used. At this time, in this embodiment, an average value of detection values of a predetermined block including the latest block is used as the detection average value regardless of whether noise is present. As a result, it is possible to accurately determine whether the toner has run out even when the toner is rapidly consumed.

  FIG. 7 shows the result of detecting the toner out in the developing device 4 by the above-described experimental apparatus by the toner out determination method of this embodiment. In this graph, the vertical axis represents the toner out determination value, and the horizontal axis represents the number of images formed by the image forming apparatus A. As shown in this graph, as a result of detecting the toner out by the above method, it is possible to almost eliminate the noise from the detection result, and it is accurately determined that the toner is out of the set image formation of about 34,000 sheets. .

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum 2 ... Charging roller 3 ... Laser scanner unit 4 ... Developing apparatus 5 ... Transfer roller 6 ... Control part 7 ... Cleaning blade 8 ... Conveyance roller 9 ... Feeding roller 10 ... Sheet stacking part 11 ... Fixing device 12 ... Discharge roller 13 ... developing container 14 ... toner bottle 15 ... developing sleeve 16 ... developing blade 17 ... toner conveying member 18 ... stirring member 19 ... supplying member 201 ... CPU
DESCRIPTION OF SYMBOLS 202 ... Memory 203 ... Operation part 204 ... Toner sensor 205 ... Toner out determination part 206 ... Display part 207 ... Stirring motor A ... Image forming apparatus

Claims (5)

A determination method for acquiring a toner amount detection result in a developing container by a toner detecting unit as an output value, and determining a toner amount in the developing container based on a determination value obtained by moving average of a predetermined number of the output values Because
An output value acquisition step of acquiring the latest output value of the toner detection means;
When the difference between the latest output value and the determination value is smaller than a threshold value, the moving average of the output value updated using the latest output value is set as a new determination value, and the difference is equal to or greater than the threshold value. In this case, a determination value update step in which a moving average of the output value updated using the determination value instead of the latest output value is used as a new determination value;
A toner amount determination step of determining a toner amount in the developing container based on the new determination value;
A toner amount determination method comprising: The toner amount determination method according to claim 1, wherein when the new determination value is equal to or less than a predetermined value, it is determined that the toner has run out. A developer container for containing toner;
Toner detecting means for detecting toner in the developing container and outputting a detection result ;
Determination value acquisition means for acquiring a determination value by a moving average of a predetermined number of output values by the toner detection means;
If the difference between the latest output value and the determination value is smaller than a threshold when the toner detection unit outputs the latest detection result, a moving average of the output values updated using the latest output value is calculated. A new determination value, and when the difference is equal to or greater than a threshold value, a determination value update unit that uses a moving average of the output values updated using the determination value instead of the latest output value as a new determination value; ,
A toner amount determination means for determining a toner amount in the developing container based on the new determination value;
An image forming apparatus comprising: A rotatable stirring member for stirring the toner in the developer container;
The image forming apparatus according to claim 3 , wherein the output value is a value based on a detection result of the toner detection unit during one rotation of the stirring member. The toner amount determination unit, the image forming apparatus according to claim 3 or claim 4 wherein the new judgment value and judging as the toner out when it becomes less than a predetermined value.