JP2009119432A - Air cleaner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air cleaner capable of displaying a contamination degree according to a real feeling of a user and controlling the suction and discharge volume of air, and to provide a control method of operation of the same. <P>SOLUTION: The air cleaner classifies the degree of air contamination into a plurality of contamination levels based on a plurality of sensibility modes with a predetermined threshold established, and carries out the control of the suction and discharge amount according to a classified air contamination level, wherein the sensibility mode as a standard and the sensibility mode of at least one or more of a lower sensibility mode or a higher sensibility mode are established. In operating of the air cleaner, if a time when a detection value of the air contamination degree is lower than the threshold of the contamination level in the sensibility mode of the side of higher sensibility, is a predetermined time, the sensibility mode is changed to the side of higher sensibility by one step, and if the time when the detection value of the air contamination degree is higher than the threshold of the contamination level in the sensibility mode of the side of lower sensibility, is the predetermined time, the sensibility mode is changed to the side of lower sensibility by one step, so that the air amount of the air cleaner is controlled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air cleaner that detects gas components, odors, smoke, dust, and the like in air and cleans the surrounding air by automatic operation.

  The structure of the conventional air cleaner is demonstrated using FIG. The air cleaner has a built-in electric blower (not shown) in the main body 1. A dust collection / deodorization filter 3 is installed in front of the electric blower. The front panel 2 is fitted into the main body 1 through a dust collecting / deodorizing filter 3. An operation switching button 5 and an operation on / off button 6 for switching the operation mode of the air purifier are arranged on the upper part of the main body.

  A gap serving as an intake port is provided between the main body 1 and the front panel 2. Air is sucked from the outside through this gap, passes through the dust collection / deodorization filter 3, enters the inside of the main body 1 through the air intake hole in the center of the main body 1, and is discharged from the top of the main body 1 to the outside by the electric blower. Is done. The air passing through the dust collection / deodorization filter 3 is discharged from the main body 1 after the dust collection / deodorization filter 3 adsorbs and removes dust and odors and is cleaned.

  A small hole is formed in the upper part of the main body, and this hole is a path through which minute air flows by suction of the electric blower, and a detection unit such as a gas sensor 4 for detecting the degree of air contamination is disposed on this path. Yes. In addition, a particle sensor that detects particles such as dust and smoke may be mounted as the detection unit.

  Since the air passing through the path where the gas sensor 4 is disposed does not pass through the dust collection / deodorization filter 3, the contamination state of the indoor air can be detected by the gas sensor 4. The degree of contamination of the air around the air cleaner is determined according to the output of the gas sensor 4, and the air volume of the electric blower (fan rotation speed) is automatically controlled to clean the air. In such an air purifier, the higher the value output from the gas sensor 4 is, the more the air flow of the electric blower is controlled, and the removal of odors and dust in the air is accelerated.

  However, when the temperature and humidity of the surrounding air change rapidly, the output value of the gas sensor 4 may hardly decrease from the saturated state even after a predetermined time has elapsed. In this case, the control unit of the air purifier determines that the ambient air has continued to be highly contaminated for a long time and continues operation. There was a difference in behavior.

In order to improve this point, in an air purifier equipped with a plurality of sensors such as a gas sensor and a particle sensor, the output value of the sensor when the air is clean is stored in advance as a reference value, and one sensor is saturated. If the sensor output value hardly decreases even after a certain period of time has elapsed since the condition was detected, check the status of other sensors, and increase the sensor reference value by a predetermined amount every predetermined time. The new reference value is updated and stored. By repeating this process until the difference between the reference value of the sensor and the output value disappears, it seems that the value of the degree of air pollution output from the sensor that detected the saturation state apparently decreases in the conventional air cleaner. And the air cleaner was operated based on that (Patent Document 1).
JP-A-10-249135

  However, the fact that the operation of the air purifier and the actual feeling of the user of the air purifier do not feel the same is not only when the sensor output reaches such a saturated state, but also in the saturated state. It was happening in the process up to. For example, even if the user smokes, the air cleaner does not respond quickly and does not operate immediately, or even after the user feels that the air has been cleaned because the sensor is sensitive. For example, the operation noise of the air cleaner is high because the air cleaner operates for a long time with a large air volume.

  As described above, in the conventional air purifier, even if the user feels that the suspended matter such as cigarette smoke has disappeared and the air has been purified, the air purifier detects that the degree of air pollution is high and detects a large amount of air. There has been a problem that the air flow of the air cleaner does not change easily even if the operation is continued or the user starts to smoke.

  In response to these problems, an air cleaner is provided with a slide switch or the like so that the user can freely switch the sensitivity of the sensor between high sensitivity, standard sensitivity, and low sensitivity. However, even when a switch for changing sensitivity is provided in the product, it is troublesome because the user needs to manually switch the slide switch according to the situation.

  The present invention is intended to solve the above-described problems, and an object of the present invention is to provide an air cleaner that performs a pollution degree display and an air volume switching control in accordance with a user's actual feeling.

  In order to achieve the above object, in the present invention, an electric blower that sucks and discharges ambient air, a cleaning unit that cleans the sucked air, a gas sensor that detects gas components and odors, dust, etc. A detection unit for detecting the degree of air pollution including a particle sensor for detecting particles and a plurality of sensitivity modes for dividing the degree of ambient air contamination into a plurality of contamination levels with a predetermined value as a threshold. Control that controls the air volume of the electric blower according to the contamination level by judging the contamination level of the surrounding air from the difference between the output value of the degree of air contamination from the section and the threshold of the contamination level set in the sensitivity mode Each of the sensitivity modes has a different contamination level threshold setting, and the output value of the air pollution level from the detection unit is compared with the contamination level threshold value in each sensitivity mode. In the air purifier in which the sensitivity mode used for control is switched according to the control unit, the control unit has at least one standard sensitivity mode and a value that is reduced by a predetermined value from the threshold value of the standard sensitivity mode. At least one of a high sensitivity side sensitivity mode having a contamination level threshold and a low sensitivity side sensitivity mode having a value increased by a predetermined value from the threshold of the standard sensitivity mode as a determined contamination level threshold It has a sensitivity mode.

  In order to achieve the above object, according to the present invention, the control unit has a predetermined time when the output value of the detection unit is smaller than the threshold value of the contamination level in the sensitivity mode that is one step higher sensitivity side than the sensitivity mode during operation. If it continues for more than the time, switch the sensitivity mode to the sensitivity mode that is one step higher sensitivity side, and the output value of the detection unit is more than the contamination level threshold value in the sensitivity mode that is one step lower sensitivity than the sensitivity mode during operation. If the large time continues for a predetermined time or more, the sensitivity mode is switched to the sensitivity mode on the one-step low sensitivity side.

  In order to achieve the above object, according to the present invention, when the output value of the detection unit is equal to or lower than the threshold value in the sensitivity mode on the one-step higher sensitivity side than the sensitivity mode during operation, the control unit is Is also controlled by switching to the sensitivity mode on the lower sensitivity side.

  In order to achieve the above object, the present invention has a clock function and a timer function in which the control unit performs control by switching the sensitivity mode to a desired sensitivity mode different from the sensitivity mode during operation at a desired time. Prepare.

  ADVANTAGE OF THE INVENTION According to this invention, the air cleaner which cleans air by the driving | operation operation | movement according to a user's actual feeling, and its control method can be provided. In addition, it is possible to provide an air cleaner and a control method therefor that generate less operation noise by selecting an operation mode or setting a timer program.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a control block diagram of the air cleaner of the present invention. First, the structure of an air cleaner according to an embodiment of the present invention will be described with reference to FIG. The air cleaner according to one embodiment includes a control unit including the microcomputer 10. A detection unit 11, an electric blower drive circuit 12, a clock circuit 13, a key input circuit 14, a display circuit 15, and a power supply synchronization signal generation circuit 16 are connected to the microcomputer 10.

  The detection unit 11 includes a gas sensor circuit 4 and a particle sensor circuit 19, detects the degree of air contamination, and outputs a detection result to the microcomputer 10.

  The electric blower drive circuit 12 is also connected to the electric blower 17 and the power supply circuit 18. The electric blower drive circuit 12 supplies electric power supplied from the power supply circuit 18 to the electric blower 17 and is electrically driven based on a control signal output from the microcomputer 10. The electric power for rotationally driving the fan of the blower 17 is controlled to control the rotational speed of the fan, that is, the air volume of the electric blower 17. The lower the fan speed, the lower the air volume and the lower the operating noise. Also, the higher the fan speed, the greater the air volume and the greater the operating noise.

  The power supply synchronizing signal generation circuit 16 is also connected to the power supply circuit 18 and outputs a signal synchronized with the voltage waveform supplied from the power supply circuit 18 to the microcomputer 10 for use in a clock function and a timer function.

  The key input circuit 14 is connected to the operation switching button 5, the operation on / off button 6, and the like, and outputs a signal based on a command input by the user of the air cleaner to the microcomputer 10.

  The display circuit 15 has a function of displaying the degree of air pollution and the like based on the output signal of the microcomputer 10 and transmitting information to the user.

  The clock circuit 13 outputs a reference signal for the operation of the microcomputer 10 to the microcomputer 10. When there is no power supply synchronizing signal circuit, this signal is used to obtain timer information.

  The microcomputer 10 receives information related to the degree of air contamination from the detection unit 11, commands related to operation by the user of the air cleaner from the key input circuit 14, and information related to time control from the power supply synchronization signal generation circuit 16. receive. Then, according to the sensitivity mode selected in advance, the air pollution level and the driving of the electric blower 17 are calculated based on the above information, and the information about the air pollution level is output to the display circuit 15, and the electric blower driving circuit 12 is operated. Control information relating to driving of the electric blower 17 is output.

  Next, operation | movement of the air cleaner by one Embodiment is demonstrated. Note that the air cleaner according to the embodiment is operated and operated in the following three sensitivity modes. FIG. 1 shows the relationship of the output threshold value at the detection unit 11 with respect to the air contamination level in the three sensitivity modes. As the sensitivity mode, a low sensitivity mode, a standard sensitivity mode, and a high sensitivity mode are set. The sensitivity mode is switched to the high sensitivity side, and the threshold value of the output value of the detection unit 11 at each contamination level is set to be low. did. Further, the sensitivity mode is switched to the low sensitivity side, and the threshold value of the output value of the detection unit 11 at each contamination level is set to be high. The air pollution level was classified into four pollution levels from 0 to 3, and the pollution level was set higher as the air pollution level increased. As the air pollution level increases, the air volume of the electric blower 17 increases and the cleaning action of the air cleaner becomes stronger.

  In the standard sensitivity mode as a reference, the contamination level threshold was set to A between level 0 and level 1, B between level 1 and level 2, and C between level 2 and level 3. In the high sensitivity mode, the contamination level threshold is between level 0 and level 1 (A-a1), between level 1 and level 2 (B-b1), and between level 2 and level 3. In between, it set to (C-c1). Further, in the low sensitivity mode, the contamination level threshold is between level 0 and level 1 (A + a2), between level 1 and level 2 (B + b2), and between level 2 and level 3 (C + c2). ).

  FIG. 3 shows a state in which the sensitivity mode is switched from the standard sensitivity to the high sensitivity side in accordance with the change in the output of the gas sensor circuit 4 when the air contamination level detected by the gas sensor circuit 4 in the detection unit 11 is zero. It is a graph. At time t = t0, the air cleaner is operating in the standard sensitivity mode, and the output of the gas sensor circuit 4 changes within the range of the contamination level 0. At t = t1, the output value of the gas sensor circuit 4 becomes smaller than the threshold value (A-a1) between the level 0 and the level 1 in the high sensitivity mode within the range of the contamination level 0, and the state is the predetermined time T1. If it continues above, the sensitivity mode of the control part 10 will switch to high sensitivity mode. At this time, the sensitivity mode is switched to the high sensitivity side, and at the same time, the threshold values of the contamination levels at level 0, level 1 and level 2 are changed from A to (A-a1), from B to (B-b1), from C to (C -C1) respectively.

  Before and after the sensitivity mode is switched to the high sensitivity side, the air contamination level is the same level 0. Therefore, the operation state of the air cleaner such as the air volume of the electric blower 17 does not change, and the operation is continued as it is. However, since the threshold value of the contamination level is changed from A to (A-a1) when the sensitivity mode is switched to the high sensitivity side, the time when the contamination level shifts from level 0 to level 1 is t = t3 to t = T2 and the contamination level switching time becomes earlier. That is, since the air volume of the electric blower 17 increases at a time earlier than usual, it is possible to respond more quickly to an increase in the degree of air pollution. Here, the predetermined time T1 is arbitrarily set from the sampling time of the output value of the gas sensor circuit 4.

  FIG. 4 is a flowchart showing a procedure for switching the sensitivity mode from the standard sensitivity to the high sensitivity side in accordance with the change in the output of the gas sensor circuit 4. In S0, the detection unit 11 detects the degree of air contamination. In S1, the detection unit 11 determines the contamination level and determines whether there is a change in the air contamination level. In S1, if there is a change in the contamination level, the procedure returns to S0 after storing the contamination level, and if there is no change in the contamination level, the procedure moves to S2.

  In S2, the sensitivity mode of the operating control unit 10 is determined. If the sensitivity mode is high sensitivity, the process returns to step S0. If the sensitivity mode is standard sensitivity, the process proceeds to step S3. If the sensitivity mode is low sensitivity, the process proceeds to step S4.

  In S3, it is determined whether the output value from the detection unit 11 is smaller than the contamination level threshold value in the high sensitivity mode within the same contamination level. When the output value is not smaller than the contamination level threshold in the high sensitivity mode, the process returns to step S0. When the output value is smaller than the contamination level threshold in the high sensitivity mode, the process proceeds to step S5.

  In S4, it is determined whether the output value from the detection unit 11 is smaller than the contamination level threshold value in the standard sensitivity mode within the same contamination level. When the output value is not smaller than the contamination level threshold in the standard sensitivity mode, the process returns to step S0. When the output value is smaller than the contamination level threshold in the standard sensitivity mode, the process proceeds to step S5.

  In S5, in S3 or S4, it is determined whether or not the state in which the output value of the detection unit 11 is smaller than the contamination level threshold is continued for a predetermined time T1 or more. If the continued time is not equal to or greater than T1, the process returns to step S0. If it is equal to or greater than T1, the process proceeds to step S6 to switch the sensitivity mode to the high sensitivity side and then returns to step S0.

  Next, FIG. 5 shows a state in which the sensitivity mode is switched to the low sensitivity side with the change in the output of the gas sensor circuit 4 when the air contamination level detected by the gas sensor circuit 4 in the detection unit 11 is 2. ing. At time t = t0 ′, the air cleaner is operating in the high sensitivity mode, and the output of the gas sensor circuit 4 changes from the contamination level 2 to the contamination level 3 at t = t1 ′. When the output value of the gas sensor circuit 4 becomes larger than the threshold C between the level 2 and the level 3 in the standard sensitivity mode within the range of the contamination level 3 at t = t2 ′, and this state continues for a predetermined time T2 or more. The sensitivity mode of the control unit 10 is switched to the standard sensitivity mode. At this time, at the same time when the sensitivity mode is switched to the low sensitivity side, the threshold value of the output value of the gas sensor circuit 4 at level 0, level 1 and level 2 is also changed from (A-a1) to A, (B-b1) to B, ( Switch from C-c1) to C.

  Further, at t = t3 ′, the output value of the gas sensor circuit 4 becomes larger than the threshold value (C + c2) between the level 2 and the level 3 in the low sensitivity mode within the range of the contamination level 3, and the state is kept for a predetermined time. If it continues for T3 or more, the sensitivity mode of the control unit is switched to the low sensitivity mode. At this time, the sensitivity mode is further switched to the low sensitivity side, and at the same time, the threshold of the contamination level at level 0, level 1 and level 2 is also switched from A to (A + a2), from B to (B + b2), and from C to (C + c2). Change.

  There is no change in the contamination level before and after the sensitivity mode is switched to the low sensitivity side, so the operation state of the air cleaner such as the air volume of the electric blower 17 does not change, and the operation is continued as it is. However, since the sensitivity mode is switched to the low sensitivity side, the contamination level threshold value changes from (C−c1) to C and further to (C + c2). Here, the predetermined times T2 and T3 are arbitrarily set from the sampling time of the sensor output value.

  After that, when the air is cleaned and the output value of the gas sensor circuit 4 decreases, the sensitivity mode remains in the low sensitivity mode, so the contamination level is lower than that in the higher sensitivity mode operation. The transition from level 3 to level 2 and from level 2 to level 1 is also advanced.

  FIG. 6 is a flowchart showing a procedure for switching the sensitivity mode to the low sensitivity side in accordance with the change in the output of the gas sensor circuit 4. In U0, the detection unit detects the degree of air contamination, and in U1, the presence or absence of a change in the air contamination level is determined. In U1, when there is a change in the contamination level, the procedure returns to U0 after storing the contamination level, and when there is no change in the contamination level, the procedure moves to procedure U2.

  In U2, the sensitivity mode in operation is determined. If the sensitivity mode is high sensitivity, the process proceeds to step U4. If the sensitivity mode is standard sensitivity, the process proceeds to step U3. If the sensitivity mode is low sensitivity, the process returns to step U0.

  In U3, it is determined whether the output value from the detection unit 11 is larger than the contamination level threshold value in the low sensitivity mode within the same contamination level. When the output value is not larger than the contamination level threshold in the low sensitivity mode, the process returns to the procedure U0. When the output value is larger than the contamination level threshold in the low sensitivity mode, the process proceeds to step U5.

  In U4, it is determined whether the output value from the detection unit 11 is larger than the contamination level threshold value in the standard sensitivity mode within the same contamination level. When the output value is not larger than the contamination level threshold value in the standard sensitivity mode, the process returns to the procedure U0. When the output value is larger than the contamination level threshold in the standard sensitivity mode, the process proceeds to step U6.

  In U5, in U3, it is determined whether or not the state where the output value of the detection unit 11 is smaller than the contamination level threshold value continues for a predetermined time T3 or more. If the continued time is not equal to or greater than T3, the process returns to step U0. If it is equal to or greater than T3, the process proceeds to step U7, the sensitivity mode is switched to the low sensitivity side by one step, and then the process returns to step U0.

  In U6, it is determined in U4 whether or not the state in which the output value of the detection unit 11 is smaller than the contamination level threshold is continued for a predetermined time T2 or more. If the continued time is not equal to or greater than T2, the process returns to step U0. If the time is equal to or greater than T2, the process proceeds to step U7, and the sensitivity mode is switched one step to the low sensitivity side, and then the process returns to step U0.

  Normally, the air cleaner is set so that the higher the contamination level, the higher the rotational speed of the electric blower 17 that circulates air through the filter, and the noise due to the rotation of the electric blower 17 also increases. It is desirable to reduce the contamination level as soon as possible and to achieve a quieter driving situation as soon as possible.

  As described above, by switching the sensitivity mode more quickly with respect to the contamination level, it is possible to increase the air volume of the electric blower 17 in response to the progress of indoor air contamination from an early stage. In addition, since the air cleaning can react at an early timing with respect to the progress and the rotational speed of the electric blower 17 can be lowered, the indoor silent environment can be quickly recovered, and the air cleaner is used. It is possible to drive closer to the actual feeling of the person.

  The sensitivity mode is automatically switched between low sensitivity mode-standard sensitivity mode, standard sensitivity mode-high sensitivity mode, and other sensitivity modes such as low sensitivity mode-standard sensitivity mode-high sensitivity mode. It is done freely between modes.

  In the above description, the gas sensor circuit 4 that detects odors and gas components is taken as an example of the detection unit 11 of the air cleaner. However, the degree of air pollution such as the particle sensor circuit 19 that detects particles such as dust and smoke is measured. The same control is possible if it is a sensor to detect. Further, even when the gas sensor circuit 4, the particle sensor circuit 19 or another sensor is used in combination to detect the air contamination level, the air cleaner can be operated in the same manner as described above.

  Also, during the daytime when the activities of air cleaners are remarkable, the indoor environment is frequently contaminated by dust and cigarette smoke. Desirable to clean. However, there may be a case where the operation time of the air cleaner in the contamination level 0 and the high sensitivity mode is sufficiently longer than the time required for switching the sensitivity mode of the detection unit of the air cleaner. That is, when the user is not active indoors or when the user is sleeping, control may be performed so that the sensitivity mode of the air cleaner is switched to a lower sensitivity side.

  When the user sleeps, the detection unit 11 of the air cleaner detects dust or the like that rolls up from the futon due to the user's turning over or the like. At this time, if the sensitivity mode of the air purifier is set to the high sensitivity side, the detection unit 11 detects dust, the contamination level increases, and the operating noise of the air purifier increases, and the user who is sleeping is detected. There is a risk of problems such as waking up.

  Therefore, when the user goes to bed, if the sensitivity mode at the contamination level 0 is switched to the low sensitivity side, the threshold value of the contamination level becomes higher, so the user wakes up due to the operating noise of the air cleaner, etc. It will be easier to avoid problems.

  In addition, by providing a timer function in the air cleaner, the program is set so that the sensitivity mode of the air cleaner is automatically switched to the low sensitivity side at the user's bedtime and switched to the high sensitivity side at the wake-up time. Can be kept. By setting the timer, it is possible to reduce the generation of operation noise due to the operation of the air purifier in a situation where the progress of air pollution in the room is slow, such as during sleep.

  In addition, by setting the sensitivity mode of the detection unit to the high sensitivity side during the user's activity time, the user can react quickly even in situations where indoor air pollution is likely to proceed, thereby It is possible to provide a cleaning operation of the air purifier according to the actual feeling.

It is a graph showing the relationship between a sensitivity mode, the output value of a detection part, and the level of contamination degree. It is a control block diagram of the air cleaner of this invention. It is a graph showing a mode that a sensitivity mode is switched to the high sensitivity side with respect to the change of the output of a detection part. It is a flowchart which shows the procedure in which a sensitivity mode switches to the high sensitivity side. It is a graph showing a mode that a sensitivity mode is switched to the low sensitivity side with respect to the change of the output of a detection part. It is a flowchart which shows the procedure in which a sensitivity mode switches to the low sensitivity side. It is a figure showing the structure of the conventional air cleaner.

Explanation of symbols

1 Body 2 Front panel 3 Dust collection / deodorization integrated filter 4 Gas sensor (gas sensor circuit)
5 Operation switching button 6 Operation on / off button 10 Microcomputer (control unit)
DESCRIPTION OF SYMBOLS 11 Detection part 12 Electric blower drive circuit 13 Clock circuit 14 Key input circuit 15 Display circuit 16 Power supply synchronous signal generation circuit 17 Electric blower 18 Power supply circuit 19 Particle sensor circuit

Claims (4)

An electric blower that sucks and discharges ambient air;
A cleaning unit for cleaning the sucked air;
A detection unit that detects the degree of air pollution, including a gas sensor that detects gas components and odors, and a particle sensor that detects particles such as dust;
A plurality of sensitivity modes for classifying the degree of contamination of the surrounding air into a plurality of contamination levels with a predetermined value as a threshold value, and an output value of the degree of air contamination from the detection unit and the sensitivity mode are set. A control unit that determines a contamination level of ambient air from a difference from a threshold of a contamination level and controls the air volume of the electric blower according to the contamination level;
Each of the sensitivity modes has a different contamination level threshold setting, and the sensitivity used for control according to the result of comparing the output value of the contamination level of air from the detection unit with the contamination level threshold value in each sensitivity mode. In an air purifier where the mode can be switched,
The control unit has a sensitivity mode as a standard, a sensitivity mode on the high sensitivity side having a value that is a predetermined value reduced from a threshold value that the standard sensitivity mode has as a first threshold value of the contamination level, and the sensitivity of the standard It has at least one sensitivity mode of the sensitivity mode on the low sensitivity side having a value increased by a predetermined value from the threshold value of the mode as the second threshold value of the determined contamination level. Air cleaner. The controller is
When the output value of the detection unit is less than the contamination level threshold in the sensitivity mode that is one step higher than the sensitivity mode during operation for a predetermined time or more, the sensitivity mode is changed to one step higher sensitivity. Switch to the sensitivity mode on the side,
When the output value of the detection unit is longer than the contamination level threshold in the sensitivity mode that is one step lower sensitivity than the operating sensitivity mode for a predetermined time or more, the sensitivity mode is changed to one step lower sensitivity side. The air cleaner according to claim 1, wherein the air cleaner is switched to a sensitivity mode. The control unit, when the output value of the detection unit is below the threshold in the sensitivity mode on the one-step high sensitivity side than the sensitivity mode during operation,
2. The air cleaner according to claim 1, wherein the air cleaner is controlled by switching to a sensitivity mode one step lower than the sensitivity mode during operation.   The control unit includes a timer function for performing control by switching to a desired sensitivity mode different from the sensitivity mode during operation of the control unit at a desired time. Item 4. The air purifier according to any one of Items 3 to 3.

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