Water closet

Abstract

To provide a water closet that can achieve both water conservation and ensuring conveyance performance.SOLUTION: A water closet 1 has: a toilet bowl body 4 equipped with a bowl portion 8 and a water storage portion W1; a washing water supply portion 6 that supplies washing water to the toilet bowl body; and a control portion 36 that controls operation of the washing water supply portion. The control portion comprises: a normal washing mode M1 in which washing water is supplied from the washing water supply portion to the toilet bowl body to wash the toilet bowl; and a double washing mode M2 that is different from the normal washing mode. The double washing mode comprises: a first washing mode M2A in which washing water is supplied from the washing water supply portion to the toilet bowl body to perform a first toilet bowl washing; and a second washing mode M2B in which a second toilet bowl washing is performed after the lapse of a predetermined time T1 since an end of the first washing mode. In the double washing mode, the control portion sets a second washing water volume Q2 used in the second washing mode to be greater than a first washing water volume Q1 used in the first washing mode.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a flush toilet, and more particularly to a flush toilet that is flushed with flush water to expel waste. [Background technology]

[0002] Conventionally, flush toilets that are cleaned with flush water to expel waste include those that perform two toilet flushing actions with one toilet flushing operation, as described in Non-Patent Document 1, for example. In such conventional flush toilets, if the user is a patient undergoing drug treatment, excrement (waste) is more likely to adhere to the toilet bowl than in healthy people, and this adhering excrement cannot be flushed away in a single flush. Because the residue of anticancer drugs taken and excreted in the excrement is toxic, it is necessary to prevent contact not only with the excretor but also with medical personnel. Therefore, even if the user does not perform a second cleaning operation after performing one cleaning operation, the excrement can be flushed out reliably by repeating one cleaning operation twice. Next, the conventional flush toilet described in Patent Document 1 has a flushing process implementation means that discharges flushing water from the discharge section to perform a first flush to clean the waste receiving surface and flush the waste toward the drain trap pipe, and then a second flush that follows the first flush and flushes the waste toward the drain trap pipe, and in one toilet flushing operation, the amount of flush water used in the first flush and the amount of flush water used in the subsequent second flush can each be changed depending on the time that has passed since the start of the flush. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-48673 [Non-patent literature]

[0004] [Non-Patent Document 1] Japan Institute of Invention and Innovation, Disclosure of Technical Information, No. 2014-502660 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the conventional flush toilets described in Non-Patent Document 1 mentioned above, taking into consideration recent water conservation trends, there is a risk that even though the toilet is flushed twice, the waste adhering to the toilet bowl may not be sufficiently flushed away, and even if the waste is discharged, depending on the interval (time) between the first and second toilet flushing operations, the waste and paper may not be transported sufficiently and may remain in the drainage channel downstream of the toilet body. Furthermore, in the conventional flush toilet described in Patent Document 1 mentioned above, even if the amount of flush water for the first flush and the subsequent second flush in a single toilet flushing operation are each changed according to the time that has passed since the start of the flush, the longer the time between the end of one toilet flushing operation and the start of the next, the greater the risk that waste and paper remaining in the drainage channel downstream of the toilet body after the previous toilet flushing operation will not be sufficiently transported by the drainage water from the next toilet flushing operation. In particular, with paper products, which have a higher permeability than waste, the water carried upstream in the drainage channel or the water contained in the paper flows downstream and tends to harden in the drainage channel due to drying, etc., which can cause the next flush to be unable to transport the stuck paper, leading to the risk of blockages.If stagnant waste sinks into the stepped grooves at the drainage pipe connection that occur due to deformation over time, it becomes difficult for the next flush to transport it. Therefore, in recent years, the question of how to balance water conservation with ensuring conveyance performance in flush toilets has become a pressing issue when aiming for long-term use of buildings.

[0006] Therefore, the present invention was made to solve the problems of the prior art mentioned above and the issues that have been required in recent years, and its purpose is to provide a flush toilet that can achieve both water conservation and ensuring conveyance performance. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a flush toilet that is flushed with flush water to discharge waste, and comprises a toilet body having a bowl section that receives waste and a water storage section located below the bowl section, a flush water supply section that supplies flush water to the toilet body, and a control section that controls the operation of the flush water supply section, the control section having a normal flush mode in which flush water is supplied from the flush water supply section to the toilet body to flush the toilet, and a double flush mode that is different from the normal flush mode, the double flush mode having a first flush mode in which flush water is supplied from the flush water supply section to the toilet body to flush the toilet a first time, and a second flush mode in which a second flush is performed a predetermined time after the end of the first flush mode, and the control section is characterized in that in the double flush mode, the volume of second flush water used in the second flush mode is set to be greater than the volume of first flush water used in the first flush mode. In the present invention configured as described above, when the double flush mode is started, the first flush of the toilet is first performed with the first flush water volume of the first flush mode. As a result, in the first flush mode, the first flush water volume is reduced compared to the second flush water volume in consideration of water conservation, while still allowing waste and paper to be discharged from the toilet body. At this time, even if waste or paper used by the user is not sufficiently transported and remains in the drainage channel downstream of the toilet body, the control unit sets the second flush water volume used in the second flush mode to be greater than the first flush water volume used in the first flush mode of the double flush mode, so that the second flush water volume can sufficiently transport the waste and paper remaining downstream of the toilet body, reliably preventing clogging with waste and paper. Therefore, in the first flush mode, the first flush water volume can be reduced compared to the second flush water volume, so that waste and paper can be discharged from the toilet body while taking water conservation into consideration, and in the second flush mode after a predetermined time has elapsed, the second flush water volume, which is greater than the first flush water volume, can sufficiently transport the waste and paper remaining downstream of the toilet body. In addition, repeated cleaning procedures can prevent stagnant dirt from drying out and solidifying, which can prevent blockages from occurring in the drainage pipes of buildings that have been in operation for a long time. As a result, it is possible to achieve both water conservation and ensuring conveyance performance in the flush toilet.

[0008] In the present invention, preferably, in the double flush mode, the control section sets the second volume of flush water based on the first volume of flush water. In the present invention configured in this manner, when performing the second flush mode of the double flush mode, the control unit sets the second flush water volume based on the first flush water volume of the first flush mode, so that the second flush water volume can be reliably set to be greater than the first flush water volume, and the total volume of flush water used throughout the entire double flush mode can be reduced. Therefore, it is possible to achieve both water conservation and ensuring conveyance performance in the flush toilet.

[0009] In the present invention, preferably, in the double flush mode, the control section sets the first flush water volume based on the amount of dirt in the bowl section. In the present invention configured in this manner, when the double flush mode is performed, the control unit sets the first flush water volume for the first flush mode based on the amount of waste in the bowl portion of the toilet body, thereby making it possible to appropriately set the first flush water volume according to the amount of waste. This ensures that waste and paper within the bowl portion of the toilet body can be discharged to the downstream side of the toilet body with an appropriate first flush water volume in the first flush mode. Therefore, in double flush mode, waste and paper can be transported efficiently using an appropriate amount of first flush water according to the amount of waste, making it possible to achieve both water conservation in the flush toilet and ensuring transport performance.

[0010] In the present invention, preferably, the control section sets the second flush water volume based on the amount of toilet paper used by the user in the double flush mode. In the present invention configured in this manner, when performing the double flush mode, the control unit sets the second flush water volume based on the amount of toilet paper used by the user, thereby making it possible to appropriately set the second flush water volume according to the amount of toilet paper used. As a result, even if, after the first flushing mode is performed, paper products are not transported sufficiently and remain stuck downstream of the toilet body, the appropriate amount of second flush water in the second flushing mode can be used to transport the waste and paper products sufficiently, reliably preventing clogging. Therefore, in double flush mode, waste and paper can be transported efficiently using an appropriate amount of second flush water according to the amount of toilet paper used, making it possible to achieve both water conservation in the flush toilet and ensuring transport performance.

[0011] In the present invention, preferably, in the double flush mode, the control unit sets a third flush water volume, which is the sum of the first flush water volume and the second flush water volume, to be less than a fourth flush water volume used when the normal flush mode is performed twice. In the present invention configured in this manner, when the double flush mode is executed, the control unit sets the third flush water volume, which is the sum of the first flush water volume and the second flush water volume, to be less than the fourth flush water volume used when the normal flush mode is executed twice, making it possible to ensure conveying performance while saving water in the flush toilet. Therefore, for the user, it is easy to use because it allows the flush toilet to both save water and ensure its conveying performance by simply operating the double flush mode once, rather than having to operate the normal flush mode twice.

[0012] In the present invention, preferably, the control section sets the predetermined time to within 10 minutes in the double cleaning mode. In the present invention configured as described above, when the double flush mode is executed, the control unit sets the predetermined time from the end of the first flush mode until the execution of the second flush mode to within 10 minutes. Therefore, even if waste or paper is not sufficiently transported downstream of the toilet body after the first flush mode is executed, the second flush mode can be executed within 10 minutes, so that the accumulated waste and paper can be reliably transported with the second flush water volume before they dry out (while retaining water). In addition, waste that is stagnating in the drain pipe downstream of the toilet body is retained in water and the backwater level is maintained above a predetermined level. This causes the wash water in the second wash mode to collide with the back-loaded water, and this back-loaded water can also be used as a propulsive force for transport, thereby achieving water conservation and high discharge force. Furthermore, for example, by setting the time from the end of the first flush until the start of the second flush to be longer than 10 minutes, and running the flush mode at regular intervals regardless of toilet use (such as an equipment protection flush mode), running double flush mode M2 ​​allows the user to use the flush toilet more comfortably and without any sense of discomfort.

[0013] In the present invention, the control section preferably sets the amount of flush water used as makeup water in the first flush mode of the double flush mode to be less than the amount of flush water used as makeup water in the normal flush mode. In the present invention configured in this manner, when the double flush mode is executed, the control unit sets the amount of flush water used as make-up water in the first flush mode to be less than the amount of flush water used as make-up water in the normal flush mode.This reduces the amount of flush water required for make-up water, while ensuring that the amount of water stored in the water storage section of the toilet body is at an appropriate water level that can at least prevent backflow of odors and the intrusion of sanitary pests into the toilet room. Furthermore, by ensuring an appropriate amount of water remains after flushing the toilet, odors caused by the water seal breaking in the water reservoir of the toilet body can be prevented, and the next flush can be carried out efficiently.

[0014] In the present invention, preferably, in the double flush mode, the control section sets the amount of flush water used as makeup water in the first flush mode to 0.3 [L] or less. In the present invention configured in this manner, when the double flush mode is executed, the control unit sets the amount of flush water used as make-up water for the first flush mode to 0.3 L or less. This reduces the amount of flush water required for make-up water, while ensuring that the amount of water stored in the water storage section of the toilet body is at an appropriate level that can at least prevent backflow of odors and the intrusion of sanitary pests into the toilet room. Furthermore, by ensuring an appropriate amount of water remains after flushing the toilet, odors caused by the water seal breaking in the water reservoir of the toilet body can be prevented, and the next flush can be carried out efficiently. [Effects of the Invention]

[0015] The flush toilet of the present invention can both save water and ensure conveyance performance. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing the overall configuration of a flush toilet according to an embodiment of the present invention. [Figure 2] 10 is a flowchart of a toilet flushing mode executed in a flush toilet according to one embodiment of the present invention. [Figure 3] 10 is a time chart for the "normal flush mode" in a flush toilet according to one embodiment of the present invention. [Figure 4] 10 is a time chart for the "double flush mode" in a flush toilet according to one embodiment of the present invention. [Figure 5] 10 shows an example of the relationship between time and flush water volume when the "double flush mode" is performed once in a flush toilet according to one embodiment of the present invention. [Figure 6]As a comparative example, FIG. 5 shows an example of the relationship between time and flush water volume when the "normal flush mode" is executed twice in a flush toilet according to one embodiment of the present invention. [Figure 7] This is a diagram that provides a time-series overview of the outflow state of water carried by waste in a drain pipe when waste in the downstream drain pipe is discharged from a flush toilet according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] A flush toilet according to one embodiment of the present invention will now be described with reference to the accompanying drawings. First, the overall structure of a flush toilet according to one embodiment of the present invention will be explained in outline with reference to FIG. FIG. 1 is a diagram showing the overall configuration of a flush toilet according to one embodiment of the present invention. As shown in Figure 1, the flush toilet 1 of this embodiment comprises a water supply channel (main water supply channel 2) through which flush water supplied from a main water supply source W0 such as a water line flows, a ceramic toilet body 4, and a flush water supply device 6 which is a flush water supply unit that supplies flush water to this toilet body 4.

[0018] Next, as shown in Figure 1, the toilet body 4 comprises a bowl portion 8 for receiving waste, a rim portion 10 formed on the upper edge of the bowl portion 8, and a drain trap portion 12 extending from the bottom of the bowl portion 8. 1, the flush water supply device 6, details of which will be described later, is provided behind the bowl portion 8 of the toilet body 4, and is a functional part that enables flush water supplied from the main water supply passage 2 to be supplied to the toilet body 4. More specifically, this functional part is powered by electricity, and includes the function of controlling the stop of flush water discharge into the bowl portion 8 of the toilet body 4.

[0019] Next, as shown in FIG. 1, a rim water channel 14 is formed inside the rim portion 10 on one of the left and right sides of the toilet body 4 (the right side when looking at the toilet body 4 from the front side). This rim water channel 14 extends from the rear side of the toilet body 4 to the front inside the rim portion 10 on one side of the toilet body 4 (the right side when looking at the toilet body 4 from the front), and then bends partway towards the rear side, forming a so-called U-turn shape. Furthermore, a rim spout 14a is provided at the downstream end (rear downstream end) of this rim conduit 14. Furthermore, the rim-side water supply passage 2a of the flush water supply device 6 is connected to the upstream side of the rim water conduit 14 of the toilet body 4. Flush water supplied from this rim-side water supply passage 2a to the rim water outlet 14a is discharged rearward from the rim water outlet 14a into the bowl section 8, thereby performing rim spouting.

[0020] Next, as shown in Figure 1, a jet water conduit 16 is formed from the outer surface to the bottom of the bowl portion 8 of the toilet body 4. The downstream side of this jet water conduit 16 is directed toward the inlet 12a of the drain trap portion 12 at the bottom of the bowl portion 8, and a jet water outlet 16a is provided at the downstream end of the jet water conduit 16. Additionally, upstream of the jet water conduit 16 of the toilet body 4, there is provided a jet-side water supply conduit 2b of the flush water supply device 6, which will be described in detail later. Flush water supplied from this jet-side water supply conduit 2b to the jet water conduit 16 of the toilet body 4 is discharged from the jet water outlet 16a towards the inlet 12a of the drain trap section 12, thereby causing jet water to be discharged. Here, as shown in FIG. 1, the upstream side of the rim-side water supply passage 2 a of the flush water supply device 6 is connected to a switching valve 18 at branch point B of the main water supply passage 2 . On the other hand, as shown in Figure 1, the upstream side of the jet side water supply passage 2b of the flush water supply device 6 is connected to the pressure pump 22 of the flush water supply device 6, which is provided downstream of the water storage tank 20 of the flush water supply device 6.

[0021] Next, the drain trap section 12 of the toilet body 4 consists of an inlet section 12a provided at the bottom of the bowl section 8, an ascending pipe 12b rising from this inlet section 12a, and a descending pipe 12c descending from this ascending pipe 12b, with the top section 12d being between the ascending pipe 12b and the descending pipe 12c. As shown in FIG. 1, the outlet 12e of the downcomer pipe 12c of the drain trap portion 12 is connected to the inlet of a drain socket S located at the rear and below of the toilet body 4. Furthermore, as shown in Figure 1, the outlet on the rear side of the drain socket S is connected to the inlet of a drain pipe D extending from the rear wall (not shown) of the toilet body 4. This allows wastewater discharged from the outlet 12e of the drain trap part 12 of the toilet body 4 to be discharged from the drain socket S into the drain pipe D on the wall side, creating a so-called "wall-side drainage system." That is, the flush toilet 1 of this embodiment is a so-called "floor-mounted flush toilet" in that the bottom surface of the toilet body 4 is installed in contact with the floor surface F, and the toilet body 4 is connected to a wall-side drain pipe D via a drain socket S, so that wastewater discharged from the toilet body 4 is drained into the wall-side drain pipe D via the drain socket S, in a so-called "wall-side drainage system" configuration.

[0022] Furthermore, the flush toilet 1 of this embodiment is not limited to the "wall-side drainage system" described above, but can also be applied to the so-called "floor-side drainage system," in which wastewater discharged from the outlet 12e of the drain trap section 12 of the toilet body 4 is discharged from the drain socket S into a drain pipe below the installation surface (floor surface F) on the bottom of the toilet body 4. Furthermore, the flush toilet 1 of this embodiment is not limited to the "floor-standing flush toilet" described above, but may also be a so-called "wall-hung flush toilet" in which the bottom surface of the toilet body 4 is positioned above and spaced apart from the floor surface F, and the rear end of the toilet body 4 is fixed to the wall behind it, and such a "wall-hung flush toilet" may also employ either the "wall-side drainage system" or "floor-side drainage system" described above.

[0023] Next, each component of the flush water supply device 6 of the flush toilet 1 according to this embodiment will be explained in outline using FIG. First, as shown in FIG. 1, the flush water supply device 6 comprises, from the upstream side to the downstream side of the main water supply passage 2, a stop valve 24, a branch fitting 26, a valve unit 28, and a switching valve 18. Next, the valve unit 28 includes a constant flow valve 30, a diaphragm-type main valve 32, and an electromagnetic valve 34 such as a solenoid valve. The flush water supply device 6 also includes a controller 36, which is a control section that controls its operation. The controller 36 is capable of functioning as a control section that controls the opening and closing operation of the on-off valve (solenoid valve 34) of the valve unit 28, the switching operation of the selector valve 18, and the rotation speed and operating time of the pressure pump 22.

[0024] Furthermore, the constant flow valve 30 of the valve unit 28 is used to restrict the flush water that has passed from the stop valve 24 in the main water supply passage 2 through the branch fitting 26 to a predetermined flow rate or less. Incidentally, in the branch fitting 26, for example, in a configuration in which a sanitary private washing device (not shown) is provided for the flush toilet 1, it is also possible to connect a water supply pipe (not shown) for supplying washing water to the sanitary private washing device (not shown). If the private parts sanitary washing device (not shown) is omitted, the branch fitting 26 may also be omitted. Furthermore, in the valve unit 28, when the solenoid valve 34 is opened under the control of the controller 36, the main valve 32 opens, and the flushing water that has passed through the main valve 32 from the constant flow valve 30 is supplied to the switching valve 18 at the branch point B downstream of the main water supply line 2. Here, the switching valve 18 is capable of supplying flushing water from the main water supply passage 2 to both the rim side water supply passage 2a and the tank side water supply passage 2c at the same time, and the ratio of the amount of water supplied to the rim side and the tank side can be changed as desired.

[0025] Next, the flush water supply device 6 is equipped with a tank device T that enables flush water supplied from the main water supply passage 2 to be supplied to the toilet body 4. This tank device T is equipped with a water storage tank 20 that is connected to the rear of the toilet body 4 and stores the flush water supplied from the main water supply passage 2, and a pump (pressurizing pump 22) that pressure-feeds the flush water in this water storage tank 20 to the toilet body 4. Furthermore, downstream of the branch point B on the downstream side of the main water supply channel 2, there are provided a rim side water supply channel 2a that communicates with the rim water conduit 14 of the toilet body 4, and a tank side water supply channel 2c that is connected to the water storage tank 20. As a result, the flush water supplied from the main water supply source W0 to the branch point B of the main water supply passage 2 is used as at least one of the rim water supply to the rim side water supply passage 2a and the tank water supply to the tank side water supply passage 2c.

[0026] Furthermore, the flush water supply device 6 is provided with a pump water supply passage 2d that extends from the downstream side of the tank side water supply passage 2c to the pressure pump 22, and a jet side water supply passage 2b that extends downstream from the pressure pump 22. As a result, in the flush toilet 1 of this embodiment, flush water supplied from the main water supply channel 2 under direct water supply pressure is supplied from the rim-side water supply channel 2a of the flush water supply device 6 through the rim water conduit 14 of the toilet body 4 to the rim water outlet 14a, making it possible for water to be discharged from the rim water outlet 14a (so-called "rim water discharge"). Furthermore, the flush water supplied from the main water supply passage 2 to the flush water supply device 6 passes through the tank side water supply passage 2c, the water storage tank 20, the pump water supply passage 2d and the pressure pump 22 of the flush water supply device 6, and then from the jet side water supply passage 2b through the jet water conduit 16 of the toilet body 4 to the jet water outlet 16a, making it possible for water to be discharged from the jet water outlet 16a (so-called ``jet water discharge''). In other words, the flush toilet 1 of this embodiment is capable of using both rim spouting of flush water directly pressurized from the main water supply line 2 and jet spouting of flush water pressurized by the pressure pump 22 from the water storage tank 20, making it a so-called hybrid flush toilet 1.

[0027] Next, an upper float switch 38 and a lower float switch 40 are respectively disposed inside the water storage tank 20. The water level inside the water storage tank 20 can be detected by these float switches 38, 40. For example, the upper float switch 38 switches on when the water level in the water tank 20 reaches a predetermined water level, and the controller 36 detects that the upper float switch 38 is on and closes the solenoid valve 34. On the other hand, the lower float switch 40 switches on when the water level in the water storage tank 20 drops to a predetermined water level that is lower than the predetermined water level detected by the upper float switch 38, and the controller 36 detects the on state of the lower float switch 40 and stops the pressure pump 22. In addition, the pressure pump 22 draws flush water stored in the water storage tank 20 into the pump water supply passage 2d, and pressurizes the flush water from this pump water supply passage 2d into the jet side water supply passage 2b, thereby discharging it from the jet water outlet 16a.

[0028] With this structure, during normal toilet flushing, the controller 36 detects the user's operation of the toilet flush switch (not shown), and activates the solenoid valve 34, the switching valve 18, and the pressure pump 22 in sequence. This causes water to start being discharged sequentially from the rim water outlet 14a and the jet water outlet 16a, and the cleaning water that has cleaned the inside of the bowl section 8 is discharged from the drain trap section 12 together with the dirt in the bowl section 8. Furthermore, after flushing is completed, the controller 36 opens the electromagnetic valve 34, the switching valve 18 is switched to the tank-side water supply passage 2c side, and flush water in the main water supply passage 2 is replenished to the water storage tank 20. When the water level in the water storage tank 20 rises and the upper float switch 38 detects the specified amount of water stored, the controller 36 closes the solenoid valve 34, causing the main valve 32 to close the main water supply line 2 and stopping the water supply.

[0029] Next, as shown in FIG. 1, the flush toilet 1 of this embodiment further comprises a human body detection sensor 42, a waste amount measurement device 44, a toilet paper usage amount measurement device 46, and an operation unit 48. First, the human body detection sensor 42 is capable of detecting the user's body, for example, when the user sits on the toilet seat (not shown) installed on the top surface of the toilet body 4, or detecting that the user has approached the toilet body 4. The waste amount measuring device 44 is also equipped with a camera or the like that can check the conditions inside the bowl portion 8, such as the bowl surface of the toilet body 4, and is able to measure the amount of waste inside the bowl portion 8 from the images captured by this camera or the like. Information on the measured amount of waste is sent to the controller 36 and processed. Furthermore, the toilet paper usage measuring device 46 is capable of measuring the amount of toilet paper actually used by the user. The measured information on the amount of toilet paper used is sent to the controller 36 and processed. The information on toilet paper usage is not limited to, for example, information obtained by contact measurement of usage as described in JP 2018-050738 A, as well as information measured by images of the amount of toilet paper used after dropping it into the toilet bowl as described in JP 06-220902 A. The operating unit 48 also includes an operating button that the user operates when starting toilet flushing (toilet flushing mode), and is made up of a remote control or the like that is provided on a part of the toilet body 4 or on a wall surrounding the flush toilet 1. When the user operates the operating unit 48, one of the toilet flushing modes, which will be described in detail later, either the "normal flushing mode M1" or the "double flushing mode M2" is executed.

[0030] Next, FIG. 2 is a flowchart of the toilet flush mode executed in a flush toilet according to one embodiment of the present invention. First, in step S1 of Figure 2, when a user sits on the toilet seat (not shown) installed on the top surface of the toilet body 4, the human body detection sensor 42 detects the user's body or detects that the user has approached the toilet body 4. Next, in step S2 of FIG. 2, waste amount measuring device 44 checks the condition inside bowl portion 8, such as the bowl surface of toilet body 4, with a camera, and starts measuring the amount of waste inside bowl portion 8. Then, in step S3 of Fig. 2, toilet paper usage amount measuring device 46 measures the amount of toilet paper actually used by the user. The measurement method is not particularly limited.

[0031] Next, in step S4 of FIG. 2, when the user operates the operating unit 48 to start toilet flushing (toilet flushing mode), a signal is sent to the controller 36. Then, in step S5, the controller 36 determines whether the "double flush mode" among the toilet flush modes is set as the default, and if the "double flush mode" is not set as the default ("NO" in step S5), in step S6 it determines whether the information regarding waste is equal to or greater than a predetermined value (whether the amount of waste is equal to or greater than a predetermined amount). If the information about the dirt is less than the predetermined value in step S6 ("NO" in step S6), the process proceeds to step S7, and the "normal washing mode M1" described in detail below is executed.

[0032] On the other hand, if the "double flush mode M2" is set as the default in step S5 of FIG. 2 (if "YES" in step S5), or if the information about the dirt is equal to or greater than a predetermined value in step S6 (if "YES" in step S6), the process proceeds to step S8, where the "double flush mode" is executed, the details of which will be described later. Next, in step S9 of FIG. 2, the "first cleaning mode M2A" of the "double cleaning mode M2" described in detail below is executed. Then, in step S10, the "second cleaning mode M2B" of the "double cleaning mode M2," which will be described in detail later, is executed, and then in step S11, the "double cleaning mode" ends.

[0033] Next, the contents of the "normal flush mode M1" executed in the flush toilet 1 according to this embodiment will be explained in detail with reference to FIGS. FIG. 3 is a time chart for the "normal flush mode M1" in the flush toilet according to this embodiment. First, as shown in Figure 3, in the standby state (time t0 to t1), the switching valve 18 is in a fully open state (rim side 100% opening) for the rim side water supply passage 2a, i.e., in a fully closed state (water tank side 0% opening) for the tank side water supply passage 2c.

[0034] Then, in the standby state (time t0 to t1) of FIG. 3, when an operation button (not shown) of operation unit 48 for starting toilet flushing (toilet flushing mode) is pressed, controller 36 receives a flushing start signal (time t1). As a result, the switching valve 18 is switched from a fully open position (rim side 100% opening) to a rim water discharge start position (rim side 30% opening and water tank side 70% opening) to the rim side water supply passage 2a (time t1 to t2). Also, at the start position of rim water discharge, the main water supply passage 2 is connected to both the rim side water supply passage 2a and the tank side water supply passage 2c, and the switching valve 18 is open 30% on the rim side and 70% on the water tank side. Here, at the start position of rim water spouting, in order to prevent the generation of abnormal noises and splashing that occur when rim water spouting occurs, a large amount of flush water is not spouted all at once from rim water spout 14a, but rather the flush water is spouted gradually from rim water spout 14a, a so-called ``soft rim water spouting'' type of water spouting.

[0035] Next, at time t3 in FIG. 3, with the switching valve 18 open 30% on the rim side and 70% on the water storage tank side, the solenoid valve 34 opens, allowing flush water to flow into the main water supply passage 2. This allows flush water to be discharged from the rim spout 14a while air present in the main water supply passage 2 upstream of the switching valve 18 is discharged into the water storage tank 20. As a result, when cleaning begins, some of the air present in the main water supply passage 2 is discharged into the tank side water supply passage 2c, and the remaining air is discharged from the rim side water supply passage 2a, so that the increase in internal pressure of the water storage tank 20 can be suppressed compared to when the switching valve 18 is fully open on the tank side as in the conventional case. In addition, since only a portion of the air present in the main water supply passage 2 is discharged from the rim water discharge port 14a, it is possible to prevent abnormal noise and water splashing that occur when water is discharged from the rim. Furthermore, since rim water spouting begins immediately after the flush start signal is received, the time lag between the flush start operation and the start of rim water spouting can be reduced. In the above-described embodiment, the starting position of the soft rim water discharge is described as being set to a position where the switching valve 18 is open 30% on the rim side and 70% on the water tank side, but this is not limited to this, and the position may be set to an opening position of 20-40% on the rim side and 80-60% on the water tank side.

[0036] Next, between times t3 and t4 in FIG. 3, the switching valve 18 is gradually switched from an opening position of 30% on the rim side and 70% on the water tank side to an opening position of 50% on the rim side and 50% on the water tank side. Between times t3 and t4, the flow rate increase rate, which is the rate of change of the increase in the flow rate of flush water supplied to the rim side water supply passage 2a, is a relatively small first flow rate increase rate f1, and conversely, the flow rate decrease rate, which is the rate of change of the decrease in the flow rate of flush water supplied to the tank side water supply passage 2c, is a relatively small first flow rate decrease rate. That is, the flow rate of flush water supplied to the rim-side water supply passage 2a increases at a relatively small first flow rate increase rate f1, and conversely, the flow rate of flush water supplied to the tank-side water supply passage 2c decreases at a relatively small first flow rate decrease rate. As a result, the amount of flush water discharged from the rim water discharge port 14a increases gradually rather than all at once, preventing the abnormal noise and splashing that occurs when water is discharged from the rim. Furthermore, since the amount of flush water supplied to the tank gradually decreases, an increase in the internal pressure of the water storage tank 20 can be suppressed.

[0037] In addition, the time (time t3 to t4) during which flush water is supplied to the rim-side water supply passage 2a at the first flow rate increase rate f1 is set to be longer than the time (time t4 to t5) during which flush water is supplied to the rim-side water supply passage 2a at the second flow rate increase rate f2 described below. As a result, it is possible to reliably suppress an increase in the internal pressure of the water tank 20, and it is also possible to reliably prevent abnormal noise and water splashing that occur when water is discharged from the rim.

[0038] Next, at time t4 in Figure 3, the switching valve 18 opens to a position where it is 50% on the rim side and 50% on the water tank side, the flow rate of flush water supplied to the rim side water supply passage 2a increases, and most of the rim side water supply passage 2a (approximately 70 to 90% of the flow path cross-sectional area of ​​each water supply passage) is almost filled with flush water. Between times t4 and t5, the switching valve 18 is gradually switched from an opening position of 50% on the rim side and 50% on the water storage tank side to a position where the rim side water supply passage 2a is fully open (rim side 100%). Between times t4 and t5, the flow rate of flush water supplied to the rim-side water supply passage 2a increases at a second flow rate increase rate f2 that is greater than the first flow rate increase rate f1, and conversely, the flow rate of flush water supplied to the tank-side water supply passage 2c decreases at a second flow rate decrease rate that is greater than the first flow rate decrease rate. As a result, the flow rate of flush water supplied to the rim side water supply passage 2a is increased at a second flow rate increase rate f2 (f2>f1) which is greater than the first flow rate increase rate f1, so that all flush water can be discharged from the rim water outlet 14a in a relatively short time. In this embodiment, the flow rate increase rate is changed in two stages (first flow rate increase rate f1 and second flow rate increase rate f2) between times t2 and t5 in FIG. 3, but the present invention is not limited to this, and the flow rate change rate may be changed in three or more stages.

[0039] Next, from times t5 to t13 in FIG. 3, a constant large amount of flush water is continuously supplied to the rim water spouting port 14a, and flush water continues to be spouted from the rim water spouting port 14a. Furthermore, after a predetermined time has elapsed from time t5, between times t6 and t11, the pressure pump 22 is turned on to perform jet water spouting, and the flush water in the water storage tank 20 is supplied to the jet water spouting outlet 16a, and the flush water is spouted from the jet water spouting outlet 16a. At this time, the jet water is discharged while the water level in the bowl section 8 and the drain trap section 12 is raised by the rim water discharge, so a strong siphoning effect can be generated in a short period of time. As a result, the amount of flush water jetted to generate the siphon effect can be reduced, thereby achieving water conservation. Furthermore, during jet water spouting, rim water spouting is performed continuously without interruption, making it difficult for air to flow into the inlet portion 12a of the drain trap portion 12, thereby suppressing siphon break noise. In addition, by jetting water while collecting floating waste in the center of the accumulated water, floating waste is prevented from sticking to the bowl surface, and floating waste can also be reliably discharged.

[0040] Here, when jet water spouting is being performed, the controller 36 controls the rotation speed of the pressure pump 22 as follows. First, the controller 36 rapidly increases the rotation speed of the pressure pump 22 from time t7 to time t8 in FIG. 3, and rotates the pressure pump 22 at high speed from time t8 to time t9. This increases the pressurizing force exerted by the pressure pump 22, causing flush water to be discharged from the jet water discharge port 16a at a high flow rate (first flow rate). At this time, since rim water is continuously discharged from the rim water outlet 14a, the flow rate of flush water discharged from the rim water outlet 14a is added, causing a large flow rate of flush water to flow into the inlet 12a of the drain trap section 12, rapidly causing a siphon action and quickly discharging the accumulated water and waste in the bowl section 8.

[0041] Next, in the case of a large flush (see the solid line in FIG. 3), the controller 36 reduces the rotation speed of the pressure pump 22 to rotate the pressure pump 22 at a medium speed from time t9 to t11 in FIG. As a result, the pressure applied by the pressure pump 22 decreases, and flush water is discharged from the jet water discharge port 16a at a medium flow rate (second flow rate) which is smaller than the first flow rate. At this time, a medium flow rate of flush water flows into the inlet 12a of the drain trap portion 12, maintaining the siphon action and ensuring that the accumulated water and waste in the bowl portion 8 is discharged. In addition, the flushing water discharged from the jet water outlet 16a is reduced from the first flow rate to the second flow rate to maintain the siphon effect, thereby achieving both drainage performance for waste and water conservation at the same time.

[0042] Furthermore, in the case of a small flush (see the dotted line in FIG. 3) between times t9 and t11 in FIG. 3, the controller 36 reduces the rotation speed of the pressure pump 22 to rotate the pressure pump 22 at a low speed, and then at a medium speed. This reduces the pressure applied by the pressure pump 22, causing flush water to be discharged from the jet water spouting port 16a at a small flow rate (third flow rate) smaller than the first and second flow rates. Then, before the siphon effect weakens, the rotation speed of the pressure pump 22 increases, causing the pressure pump 22 to rotate at medium speed, and flush water is discharged from the jet water spouting port 16a at a medium flow rate (second flow rate). This allows the siphoning action to be maintained at a lower flow rate than in the case of a large flush.

[0043] Next, at time t10 in FIG. 3, when the flush water level in the water storage tank 20 drops below L1 and the lower float switch 40 turns on, operation of the pressure pump 22 is stopped after a predetermined delay time (time t11). At this time, the rotation speed of the pressure pump 22 is slowly reduced between time t11 and time t12 so that the amount of water discharged from the jet water discharge port 16a gradually decreases. This makes it possible to prevent the generation of cutting noises that occur when jet water spouting is suddenly stopped.

[0044] Next, jet water spouting ends at time t11 in Figure 3. At this time, rim water spouting is still continuing, and only rim water spouting (post-rim water spouting) continues for a predetermined time from time t11 to time t13. Thereafter, between times t13 and t14, the switching valve 18 is switched from the rim side fully open to the water storage tank side fully open. As a result, flush water is stored in the water storage tank 20.

[0045] Next, at time t15 in FIG. 3, when the water level in the water storage tank 20 reaches a predetermined water level L1, the lower float switch 40 is turned off. Then, at time t16, when the water level in the water storage tank 20 rises to a predetermined water level L2, the upper end float switch 68 is turned on. Furthermore, between times t16 and t17, water supply to the tank continues. Then, at time t17, the solenoid valve 34 closes, causing the main valve 32 to also close, and the supply of flush water to the water storage tank 20 is stopped. As a result, the water level in the water storage tank 20 reaches a predetermined water level L3 that is slightly higher than L2, and the water storage tank 20 becomes full.

[0046] Next, between times t17 and t18, the switching valve 18 is maintained in a position in which it is fully open to the tank-side water supply passage 2c. Furthermore, between times t18 and t19, the switching valve 18 is switched from a position that fully opens the tank-side water supply passage 2c to a position that fully opens the rim-side water supply passage 2a. Then, at time t19, the switching valve 18 returns to the fully open position in the rim-side water supply passage 2a, and the standby state (the same state as from time t0 to t1) is restored, completing one normal flush mode M1.

[0047] Here, as shown in Figure 3, in normal flushing mode M1, toilet flushing of the toilet body 4 is performed between times t1 and t12, and makeup water (refill water) is replenished to the water storage section W1 in the bowl section 8 of the toilet body 4 between times t12 and t14. More specifically, as shown in FIG. 3, between times t1 and t6 in the normal flush mode M1 between times t1 and t11, a toilet flush with rim spouting in the first half (so-called "pre-rim flush") is performed. Furthermore, between times t6 and t11, a toilet flush with medium rim spouting (so-called "medium rim flush") is performed. At the same time, between times t6 and t11, a toilet flush with jet spouting (so-called "jet flush") is performed. Furthermore, between times t12 and t14, part of the toilet flush with rim water spouting in the latter half (so-called "post rim flush") is executed. That is, in this embodiment, even immediately after the "jet flush" ends at time t11, the siphon action continues between times t11 and t12, so the toilet flush is being performed as part of the "post rim flush."

[0048] In this embodiment, as an example, the period during which toilet flushing is performed in normal flushing mode M1 from time t1 to t12 shown in Figure 3 is a flushing period ("toilet flushing period A0") for discharging waste present in the bowl portion 8 of the toilet body 4 into the drain trap portion 12. Furthermore, since this embodiment is a hybrid flush toilet 1, a form in which toilet flushing is performed using the above-mentioned "front rim flush," "middle rim flush," and "jet flush," as well as part of the "rear rim flush," will be described, but the form is not limited to this, and toilet flushing may also be performed using only the "front rim flush," "middle rim flush," and "jet flush." On the other hand, between times t12 and t14, the flush water from the "post rim flush" is used as make-up water (refill water), and the make-up water (refill water) is supplied to the water collection section W1 in the bowl section 8 of the toilet body 4, so that a water collection surface (sealing surface) WL0 is formed in the water collection section W1 in the bowl section 8. That is, the period from time t12 to time t14 shown in FIG. 3 is a period for forming a pooled water surface (sealed water surface) WL0 in bowl portion 8 with makeup water ("make-up water period a0"). Furthermore, in this embodiment, because the flush toilet 1 is a hybrid type, when flush water containing waste in the bowl portion 8 is discharged due to the siphon action during toilet flushing, the water pooling surface (water sealing surface) WL0 is not formed in the water pooling portion W1 in the bowl portion 8, resulting in what is known as a "broken seal state." For this reason, in a hybrid flush toilet 1, it is essential to supply water to the water reservoir W1 in the bowl 8, and essentially, the water reservoir surface (sealed surface) WL0 is formed after the siphon action has ended.

[0049] Incidentally, as a variation of the flush toilet 1 of this embodiment, instead of the hybrid flush toilet, a so-called wash-down flush toilet, which discharges waste by the difference in water level between the bowl and the drain trap, may be used. In such a wash-down flush toilet, after the flush water in the bowl flows down, its force decreases and the discharge of waste ends, so a minimum level of pooled water may be formed even without replenishment of make-up water, so make-up water after flushing the toilet may be omitted or the amount of make-up water may be reduced. The make-up water (refill water) is not limited to the use of wash water from the "post-rim wash", and wash water supplied from a local wash device (not shown) may be used as make-up water. In addition, the cleaning water used when cleaning the spray nozzle of a local cleaning device (not shown) that sprays cleaning water toward the user's local areas may be used as make-up water (refill water), or disinfectant water sprayed into the bowl portion 8 of the toilet body 4 after the toilet has been flushed may be used as make-up water (refill water).

[0050] Next, the "double flush mode M2" executed in the flush toilet 1 according to this embodiment will be explained in detail with reference to Figs. 1 and 4 to 7. First, Figure 4 is a time chart for the "double flush mode M2" in a flush toilet 1 according to this embodiment, and Figure 5 shows an example of the relationship between time and flush water volume when the "double flush mode" is performed once in a flush toilet according to this embodiment. First, as shown in FIGS. 4 and 5, in "double flush mode M2", toilet flushing is performed in "first flush mode M2A" from time t1' to time t14'. Then, after the predetermined time T1 has elapsed, the toilet flush is performed in the "second flush mode M2B" from time t101' to time t114'.

[0051] Also, as shown in Figures 4 and 5, in the "first flush mode M2A" from time t1' to t14', the period from time t1' to t12' is the period during which the first toilet flush is performed with the first flush water volume Q1 [L] (the "first toilet flush period A1"). Thereafter, from time t12' to t14', there is a period ("first replenishment water period a1") during which the first replenishment water is supplied to the water storage section W1 in the bowl section 8 of the toilet body 4 at a first replenishment water volume q1 [L]. Here, in the first toilet flush period A1 from time t1' to t12', a "pre-rim flush" is performed from time t1' to t6', a toilet flush using a "middle rim flush" and a "jet flush" is performed from time t6' to t11', and a toilet flush using part of a "post-rim flush" is performed from time t11' to t12'. Furthermore, during the first make-up water period a1 from time t12' to t14', the flush water from the "post-rim flush" is used as the first make-up water (refill water), and the make-up water (refill water) is replenished to the water storage section W1 in the bowl section 8 of the toilet body 4.

[0052] Next, the "second flush mode M2B" is executed from time t13' to t17' shown in FIG. 4, after flush water is stored in the water tank 20, until time t101' to t114', but the period from time t101' to t112' is the period during which the second toilet flush is executed with the second flush water volume Q2 [L] (the "second toilet flush period B1"). Thereafter, from time t112' to t114', there is a period ("second makeup water period b1") during which a second makeup water supply is carried out to the water storage section W1 in the bowl section 8 of the toilet body 4 at a second makeup water volume q2 [L].

[0053] Furthermore, as a comparative example to FIG. 5, FIG. 6 shows an example of the relationship between time and flush water volume when "normal flush mode M1" is executed twice in a flush toilet according to this embodiment. Here, the "double cleaning mode M2" shown in FIGS. 4 and 5 will be described, focusing on the differences from the "normal cleaning mode M1" shown in FIGS. First, the first flush period A1 from time t1' to time t12' in the first flush mode M2A of the double flush mode M2 ​​shown in FIGS. 4 and 5 is set to be shorter than the respective toilet flush periods A0 from time t1 to time t12 and time t101 to time t112 in the normal flush mode M1 shown in FIGS. 3 and 6 (A1 <A0)。 As a result, the first flush water volume Q1 [L] used in the first toilet flush period A1 of the first flush mode M2A of the double flush mode M2 ​​is set to a smaller volume than the flush water volume Q0 [L] used in the toilet flush period A0 of the normal flush mode M1 (Q1 <Q0)。

[0054] Here, the first flush water volume Q1 [L] used in the first toilet flush period A1 of the first flush mode M2A of the double flush mode M2 ​​can be set by the controller 36 based on information such as the measured value of the amount of waste in the bowl section 8 transmitted from the waste volume measuring device 44. For example, in the first toilet flush period A1 of the first flush mode M2A of the double flush mode M2 ​​shown in FIGS. 4 and 5, compared to the toilet flush period A0 of the normal flush mode M1 shown in FIGS. 3 and 6, by shortening the time during which the pre-rim flush is performed from time t1' to t6' and by shortening the time during which the middle rim flush and jet flush are performed from time t6' to t11', the first flush water volume Q1 [L] shown in FIG. 5 can be set to a smaller value than the flush water volume Q0 [L] shown in FIG. 6 (Q1 <Q0)。 More specifically, for example, if the amount of dirt adhering to the bowl surface (dry surface) of the bowl portion 8 of the toilet body 4 is small, the time for the pre-rim flush (time t1' to t6') may be set short, and the time for the middle rim flush and jet flush (time t6' to t11') may be set short.

[0055] Next, the first makeup water period a1 from time t12' to time t14' in the first cleaning mode M2A of the double cleaning mode M2 ​​shown in FIGS. 4 and 5 is set to be shorter than the makeup water period a0 from time t12 to time t14 in the normal cleaning mode M1 (a1 <a0)。 As a result, during the first water supply period a1 of the first flushing mode M2A of the double flushing mode M2, a minimum water pooling surface (sealing surface) WL0 is formed in the water pooling section W1 within the bowl section 8 of the toilet body 4, while the water supply period a1 is set to be shorter than the water supply period a0 of the normal flushing mode M1, thereby saving water. Here, the first makeup water amount q1 [L] supplied during the first makeup water period a1 in the first flushing mode M2A of the double flushing mode M2 ​​shown in FIG. 5 is set to an amount less than the makeup water amount q0 [L] supplied during the makeup water period a0 in the normal flushing mode M1 shown in FIG. 6 (q1 <q0)。 In addition, when executing the double flush mode M2, the controller 36 sets the amount of flush water used as makeup water in the first flush mode M2A (first makeup water amount q1 [L]) to 0.3 [L] or less, which is less than the amount of flush water used as makeup water in the normal flush mode (makeup water amount q0 [L]).

[0056] Next, the tank water supply time from time t13' to t17' after the first flush mode M2A in the double flush mode M2 ​​shown in Figure 4 is set to be shorter than the tank water supply time from time t13 to t17 in the normal flush mode M1 shown in Figure 3. More precisely, in the case of a hybrid flush toilet such as the flush toilet 1 of this embodiment, if the first toilet flush period A1 of the first flush mode M2A of the double flush mode M2 ​​(particularly the jet flush time from time t6' to t11') is made shorter than the toilet flush period A0 of the normal flush mode M1, the amount of flush water remaining in the water storage tank 20 will increase, and the tank water supply time from time t13' to t17' will be shorter.

[0057] Also, as shown in Figures 4 and 5, in the double flush mode M2, the second toilet flush period B1 and the second make-up water period b1 of the second flush mode M2B are set to be longer than the first toilet flush period A1 and the first make-up water period a1 of the first flush mode M2A, respectively (B1>A1, b1>a1). That is, in the double flush mode M2, the controller 36 is capable of setting the second flush water volume Q2 and the second makeup water volume q2 to be used in the second flush mode M2B based on the first flush water volume Q1 and the first makeup water volume q1 to be used in the first flush mode M2A, respectively, and is also configured to set the second flush water volume Q2 and the second makeup water volume q2 to be greater than the first flush water volume Q1 and the first makeup water volume q1 to be used in the first flush mode M2A, respectively (Q2>Q1, q2>q1).

[0058] On the other hand, the second flush water volume Q2 [L] and the second makeup water volume q2 [L] of the second flush mode M2B of the double flush mode M2 ​​shown in Figure 5 can be set by the controller 36 based on information such as the measured value of toilet paper usage transmitted from the toilet paper usage measurement device 46. Here, the second flush water volume Q2 [L] and the second makeup water volume q2 [L] may be set to be equal to or less than the flush water volume Q0 [L] and makeup water volume q0 [L] in the normal flush mode M1 shown in FIG. 6 (Q2≦Q0, q2≦q0), or may be set to be greater than the flush water volume Q0 [L] and makeup water volume q0 [L] (Q2>Q0, q2>q0).

[0059] Next, as shown in FIGS. 4 and 5, in this embodiment, when executing the double cleaning mode M2, the controller 36 can set the predetermined time T1 from the end of the first cleaning mode M2A at time t14′ to the execution of the second cleaning mode M2B at time t101′ to within 10 minutes (T1≦10 minutes). Here, Figure 7 is a diagram that provides a time-series overview of the outflow state of the water (so-called "backwater") carried by the waste in the drain pipe D when the waste w in the downstream drain pipe D is discharged from the flush toilet 1 of this embodiment. First, in the case of waste w0 including paper such as toilet paper that is drained from the flush toilet 1 into the drain pipe D, immediately after it has stopped in the drain pipe D in Figure 7 (A), there is drainage water (so-called "back water") at a water level h1 relative to the bottom surface 50 of the drain pipe D on the upstream side (back side). Furthermore, as shown in (B) of Figure 7, after 10 minutes have passed since the waste w0 first arrived in the drain pipe D, there is drainage water (backwater) at a water level h2 upstream (back side) of the waste w0 relative to the bottom surface 50 of the drain pipe D. In FIG. 7B, the water retained in the waste w0, including paper such as toilet paper, gradually seeps downstream, so the water level h2 in FIG. 7B is lower than the water level h1 in FIG. 7A (h2 Here, the backwater at water level h2 shown in Figure 7(B) collides with the leading water w1 of sewage following from upstream, and is again in a state where it can sufficiently transport the sewage w0.

[0060] Next, as shown in (C) of Figure 7, after 20 minutes have passed since the waste w0 was retained in the drain pipe D, there is drainage water (backwater) at a water level h3 upstream (back side) of the waste w0 relative to the bottom surface 50 of the drain pipe D. In FIG. 7C, the water retained in the waste w0 gradually seeps further downstream, so the water level h3 in FIG. 7C is lower than the water levels h1 and h2 in FIG. 7A and FIG. 7B (h3 <h2 As a result, the permeability of the waste w0 in Figure 7 (C) is reduced due to the paper contained within it being united, so even if the leading water w1 of the following waste collides with the backwater at water level h3, it is unable to sufficiently transport the waste w0. Furthermore, as shown in (D) of Figure 7, after 30 minutes have passed since the waste w0 was retained in the drain pipe D, there is a small amount of drainage water (backwater) at a water level h4 upstream (back side) of the waste w0 relative to the bottom surface 50 of the drain pipe D. ​​However, in (D) of Figure 7, the moisture and backwater retained in the waste w0 has completely seeped out to the downstream side, so the backwater level h4 in (D) of Figure 7 is lower than the backwater levels h1, h2, and h3 shown in (A) to (C) of Figure 7 (h4 <h3<h2 As a result, the waste w0 in Figure 7 (D) is stuck to the wall surface inside the drainage pipe D along with the paper and other materials contained therein, so that even if the leading water w1 of the following waste collides with the backwater at water level h4, it is unable to transport the waste w0 at all. As a result of these findings, the inventors were able to confirm that when executing the double flush mode M2, if the controller 36 sets the predetermined time T1 from the end of the first flush mode M2A at time t14' to the execution of the second flush mode M2B at time t101' to within 10 minutes (T1≦10 minutes), then the waste w0, including paper products such as toilet paper, can be sufficiently transported by the collision of the back-loading water with the leading water w1 of the following waste.

[0061] Next, a specific example of the amount of flush water used in double flush mode M2 ​​will be described with reference to FIGS. For example, in the normal flush mode M1 shown in Figure 6, if the total flush water volume Q0 and makeup water volume q0 used in the three stages of toilet flushing, namely the large flush mode, the small flush mode, and the eco small flush mode, are set to 4.8 [L], 3.8 [L], and 2.2 [L], respectively, then in a first specific example of the flush water volume used in the double flush mode M2 ​​shown in Figure 5, the first flush water volume Q1 and first makeup water volume q1 in the first flush mode M2A are set to 2.2 [L] and 0.2 [L], respectively. The second flush water volume Q2 and second makeup water volume q2 in the second flush mode M2B are set to 3.0 [L] (corresponding to the eco-low flush mode of the normal flush mode M1) and 0.8 [L], respectively. ​As a result, the third flush water volume Q3 (= Q1 + q1 + Q2 + q2), which is the sum of the first flush water volume Q1, the first makeup water volume q1, the second flush water volume Q2, and the second makeup water volume q2 used throughout the double flush mode M2, is 6.2 [L] (Q3 = 2.2 [L] + 0.2 [L] + 3.0 [L] + 0.8 [L] = 6.2 [L]). On the other hand, the amount of flush water used when the large flush mode of the normal flush mode M1 is repeated twice (fourth flush water amount Q4) is 9.6 [L] (Q4 = 4.8 [L] + 4.8 [L] = 9.6 [L]). Therefore, the third flush water volume Q3 (= 6.2 [L]) used in the entire double flush mode M2 ​​is set to be less than the fourth flush water volume Q4 (= 9.6 [L]) used when the normal flush mode is performed twice (Q3 = 6.2 [L] <Q4=9.6[L])。

[0062] Next, as a second specific example of the amount of flush water used in the double flush mode M2 ​​shown in Figure 5, when the amount of waste is excessive or when a large amount of toilet paper has been used, the first flush water amount Q1 and the first make-up water amount q1 of the first flush mode M2A are set to 3.0 [L] (equivalent to the eco small flush mode of the normal flush mode M1) and 0.2 [L], respectively. Furthermore, the second flush water volume Q2 and the second makeup water volume q2 in the second flush mode M2B are set to 4.0 [L] and 0.8 [L], respectively. As a result, the third flush water volume Q3 (= Q1 + q1 + Q2 + q2), which is the sum of the first flush water volume Q1, the first makeup water volume q1, the second flush water volume Q2, and the second makeup water volume q2 used throughout the double flush mode M2, is 6.2 [L] (Q3 = 3.0 + 0.2 + 4.0 + 0.8 = 8.0 L). On the other hand, the amount of flush water used when the large flush mode of the normal flush mode M1 is repeated twice (fourth flush water amount Q4) is 9.6 [L] (Q4 = 4.8 + 4.8 = 9.6 [L]), so the third flush water amount Q3 (= 8.0 [L]) used throughout the double flush mode M2 ​​is set to be less than the fourth flush water amount Q4 (= 9.6 [L]) used when the normal flush mode is performed twice (Q3 = 8.0 [L] <Q4=9.6[L])。

[0063] Next, the operation of the flush toilet 1 according to one embodiment of the present invention described above will be explained with reference to FIGS. First, according to the flush toilet 1 of this embodiment, when the double flush mode is started, the first flush of the toilet is first performed with the first flush water volume Q1 [L] of the first flush mode M2A, and then the first supply of water is performed with the first supply of water volume q1 [L]. As a result, in the first flush mode M2A, the first flush water volume Q1 [L] and the first make-up water volume q1 [L] can be reduced compared to the second flush water volume Q2 [L] and the second make-up water volume q2 [L] in the second flush mode M2B, respectively, in consideration of water conservation, while still allowing waste and paper products such as toilet paper to be discharged from the toilet body 4. At this time, even if waste or paper used by the user is not sufficiently transported and remains in the drain pipe D, which is the drainage channel downstream of the toilet body 4 (see (A) of Figure 7), the controller 36 can set the second flush water volume Q2 [L] and second makeup water volume q2 [L] used in the second flush mode M2B of the double flush mode M2 ​​to be greater than the first flush water volume Q1 [L] and first makeup water volume q1 [L] used in the first flush mode M2A, respectively. Therefore, the second flush water volume Q2 [L] used in the second flush mode M2B is sufficient to transport the waste w0 and paper remaining downstream of the toilet body 4 after the previous toilet flush in the first flush mode M2A, thereby reliably preventing clogging of the waste w0 and paper. Furthermore, in the first flush mode M2A of the double flush mode M2, the first flush water volume Q1 [L] and the first make-up water volume q1 can be reduced compared to the second flush water volume Q2 [L] and the second make-up water volume q2 of the second flush mode M2B, respectively, so that waste and paper can be discharged from the toilet body 4 while taking water conservation into consideration. Furthermore, after the first flushing mode M2A is completed and a predetermined time T1 has elapsed (for example, T1 = 10 [min]), in the second flushing mode M2B, the second flushing water volume Q2 [L], which is greater than the first flushing water volume Q1 [L], can sufficiently transport the waste w0 and paper remaining downstream of the toilet body. In addition, repeated cleaning procedures can prevent stagnant dirt from drying out and solidifying, which can prevent blockages from occurring in the drainage pipes of buildings that have been in operation for a long time. As a result, the flush toilet 1 can both save water and ensure its conveyance performance.

[0064] Next, according to the flush toilet 1 of this embodiment, when the second flush mode M2B of the double flush mode M2 ​​is performed, the controller 36 sets the second flush water volume Q2 [L] based on the first flush water volume Q1 [L] of the first flush mode M2A. This makes it possible to reliably set the second flush water volume Q2 [L] to be greater than the first flush water volume Q1 [L], and also to reduce the total volume of flush water used throughout double flush mode M2. Therefore, it is possible to achieve both water conservation in the flush toilet 1 and ensure conveyance performance.

[0065] Furthermore, with the flush toilet 1 of this embodiment, when performing double flush mode M2, the controller 36 can set the first flush water volume Q1 [L] for the first flush mode M2A based on information about the amount of waste in the bowl section 8 of the toilet body 4 measured by the waste volume measuring device 44, so that the first flush water volume Q1 [L] can be set appropriately according to the amount of waste. This ensures that waste and paper within the bowl portion 8 of the toilet body 4 is discharged downstream of the toilet body 4 with the appropriate first flush water volume Q1 [L] in the first flush mode M2A. Therefore, in double flush mode, waste and paper can be transported efficiently using an appropriate first flush water volume Q1 [L] according to the amount of waste, making it possible to achieve both water conservation in the flush toilet 1 and ensuring transport performance.

[0066] Furthermore, with the flush toilet 1 of this embodiment, when performing double flush mode M2, the controller 36 sets the second flush water volume Q2 [L] and the second makeup water volume q2 [L] based on the amount of toilet paper used measured by the toilet paper usage measuring device 46, thereby making it possible to appropriately set the second flush water volume Q2 [L] and the second makeup water volume q2 [L] according to the amount of toilet paper used by the user. As a result, even if, after the first flushing mode M2A is executed, paper items are not sufficiently transported and remain stuck downstream of the toilet body 4, the waste w0 and paper items can be sufficiently transported with the appropriate second flushing water volume Q2 [L] of the second flushing mode M2B, thereby reliably preventing clogging. Therefore, in double flush mode M2, waste w0 and paper can be transported efficiently using an appropriate second flush water volume Q2 [L] according to the amount of toilet paper used by the user, thereby achieving both water conservation in the flush toilet 1 and ensuring transport performance.

[0067] Furthermore, with the flush toilet 1 of this embodiment, when executing double flush mode M2, the controller 36 sets the third flush water volume Q3 [L], which is the sum of the first flush water volume Q1 [L], first makeup water volume q1 [L], second flush water volume Q2 [L], and second makeup water volume q2 [L], to be less than the fourth flush water volume Q4 [L] used when normal flush mode M1 is performed twice, so that the flush toilet 1 can conserve water while ensuring conveying performance. Therefore, for the user, it is easy to use because it is possible to achieve both water conservation and ensuring conveyance performance of the flush toilet 1 by simply operating the double flush mode M2 ​​once, without having to operate the normal flush mode M1 twice.

[0068] Furthermore, with the flush toilet 1 of this embodiment, when executing the double flush mode M2, the controller 36 can set the predetermined time T1 from the end of the first flush mode M2A at time t14' until the execution of the second flush mode M2B at time t101' to within 10 minutes (T1≦10 minutes). As a result, even if, after the first flushing mode M2A is executed, waste w0 or paper is not sufficiently transported and remains on the downstream side of the toilet body 4 (see (A) and (B) of Figure 7), by executing the second flushing mode M2B within the specified time T1 of 10 [min], the remaining waste w0 or paper can be reliably transported with the second flush water volume Q2 [L] before it dries out completely (while retaining water). In addition, for the waste w0 stagnating in the drain pipe D downstream of the toilet body 4, if the predetermined time T1 that has elapsed since the first flushing mode M2A of the double flushing mode M2 ​​ended at time t14' is within 10 minutes, the water level h of the backwash water is maintained above the predetermined water level h2 (h≧h2), and the waste w0 is sufficiently water-retained (see (A) and (B) of Figure 7). This causes the back-loaded water to collide with the cleaning water of the second cleaning mode M2B (the leading water w1 of the following filth), and this back-loaded water can also be used as a propulsive force for transport, thereby achieving water conservation and high discharge power. Furthermore, for example, by setting the time T1 from the end of the first flush (first flush mode M2A) until the start of the second flush (second flush mode M2B) to be longer than 10 minutes, and running the double flush mode M2, users can use the flush toilet 1 more comfortably and without feeling any discomfort, compared to running the flush mode at regular intervals regardless of whether the toilet is in use, such as with an equipment protection flush mode.

[0069] Furthermore, with the flush toilet 1 according to this embodiment, when executing the double flush mode M2, the controller 36 sets the amount of flush water used in the makeup water for the first flush mode M2A (first makeup water amount q1 [L]) to be less than the amount of flush water used in the makeup water for the normal flush mode (make-up water amount q0 [L]), and also sets the amount of flush water used in the makeup water for the first flush mode M2A to 0.3 [L] or less. This reduces the amount of flush water required for makeup water, while ensuring that the amount of water stored in the water storage section W1 of the toilet body 4 is at an appropriate level that can at least prevent odor backflow and the intrusion of sanitary pests into the toilet room. Furthermore, by ensuring an appropriate amount of water is stored after the first toilet flush (after the toilet is flushed in the first flushing mode M2A), it is possible to prevent odors from occurring due to the water sealing breaking on the water storage surface (sealing surface) WL0 of the water storage section W1 of the toilet body 4, and the next flush (toilet flushing in the second flushing mode M2B) can be carried out efficiently.

[0070] In the flush toilet 1 according to the present embodiment described above, as an example, a hybrid flush toilet configuration has been described in which a flush water supply device 6 is used as the flush water supply section that supplies flush water to the toilet body 4, but the flush water supply section that supplies flush water to the toilet body 4 may also be in the form of a water storage tank that is tightly coupled to the rear top surface of the toilet body 4 (a so-called "tightly coupled tank"). When such a sealed tank configuration is adopted, instead of using a pressure pump 22 as a means for supplying flush water stored in the water storage tank to the toilet body 4, a so-called gravity-fed water storage tank configuration is applied, in which the flush water in the water storage tank is caused to fall by gravity and supplied to the toilet body 4. Alternatively, the flush water supply section that supplies flush water to the toilet body 4 may be a direct water pressure type or flush valve type that directly utilizes the water supply pressure of tap water and supplies it directly to the toilet body 4. [Explanation of symbols]

[0071] 1. Flush toilet according to one embodiment of the present invention (hybrid flush toilet) 2 Main water supply channel 2a Rim side water supply channel 2b Jet side water supply channel 2c Tank side water supply channel 2d Pump supply line 4 Toilet body 6 Cleaning water supply device (cleaning water supply section) 8 Bowl section 10 Rim 12 Drain trap section 12a Inlet of drain trap 12b Drain trap riser 12c Downcomer pipe of drain trap 12d Top of drain trap 12e Outlet of the drain trap 14 Rim Waterway 14a Rim Spout 16 Jet Waterway 16a Jet water outlet 18 Switching valve 20 Water Tank 22 Pressure pump 24 Stop valve (supply source) 26 Branch fitting (supply source) 28 Valve unit 28a Water supply pipe elbow 30 Constant flow valve 32 Diaphragm type main valve 34 Solenoid valve 36 Controller (control unit) 38 Upper float switch 40 Lower float switch 42 Human body detection sensor 44 Waste volume measuring device 46 Toilet paper usage measuring device 48 Control section 50 Bottom of drain pipe A0 Toilet flushing period in normal flush mode A1 First flush period of first flush mode in double flush mode a0 Water replenishment period in normal cleaning mode a1 First make-up water period in the first cleaning mode of the double cleaning mode B Branch B1 Second flush period of the second flush mode in the double flush mode b1 Second make-up water period in the second cleaning mode of the double cleaning mode D Drain pipe F Floor f1 First flow rate increase rate f2 Second flow rate increase rate h1 Water level h2 Water level h3 Water level h4 Water level L1 Water level in the water tank L2 Water level in the water tank L3 Water level in the water tank M1 Normal cleaning mode M2 2-times cleaning mode M2A 1st cleaning mode of 2-time cleaning mode M2B Second cleaning mode of the double cleaning mode Q0 Amount of flush water used during toilet flushing in normal flush mode q0 Amount of make-up water supplied during the make-up water period in normal cleaning mode Q1 The amount of water used during the first flush period in the first flush mode of the double flush mode q1 The amount of first makeup water replenished during the makeup water period in the first cleaning mode of the double cleaning mode Q2 Volume of water used during the second flush period in the second flush mode of the double flush mode q2 Amount of second make-up water replenished during the make-up water period in the second cleaning mode of the double cleaning mode Q3 The third flush water volume is the sum of the first flush water volume, the first makeup water volume, the second flush water volume, and the second makeup water volume. Q4 The fourth flush water volume used when using the normal flush mode twice S drain socket T-tank device T1 Predetermined time W0 Main water supply source W1 Reservoir WL0 Water storage surface (water sealing surface) w0 filth w1 Leading water

Claims

1. A flush toilet that is flushed with flush water to discharge waste, a toilet body having a bowl portion for receiving waste and a water collection portion provided below the bowl portion; a flush water supply unit that supplies flush water to the toilet body; a control unit that controls the operation of the cleaning water supply unit, the control unit supplies flush water from the flush water supply unit to the toilet body and performs a normal flush mode to flush the toilet; and a double cleaning mode different from the normal cleaning mode. The double flush mode comprises a first flush mode in which flush water is supplied from the flush water supply unit to the toilet body to perform a first toilet flush, and a second flush mode in which a second toilet flush is performed a predetermined time after the first flush mode ends, A flush toilet characterized in that, in the double flush mode, the control unit sets the second flush water volume used in the second flush mode to be greater than the first flush water volume used in the first flush mode.

2. 2. The flush toilet according to claim 1, wherein the control unit, in the double flush mode, sets the second flush water volume based on the first flush water volume.

3. 2. The flush toilet according to claim 1, wherein the control unit sets the first flush water volume based on the amount of waste in the bowl portion in the double flush mode.

4. 2. The flush toilet according to claim 1, wherein the control unit sets the second flush water volume in the double flush mode based on the amount of toilet paper used by the user.

5. 2. The flush toilet according to claim 1, wherein the control unit sets a third flush water volume, which is the sum of the first flush water volume and the second flush water volume, in the double flush mode to be less than a fourth flush water volume used when the normal flush mode is performed twice.

6. 2. The flush toilet according to claim 1, wherein the control unit sets the predetermined time to 10 minutes or less in the double flush mode.

7. 2. The flush toilet according to claim 1, wherein the control unit sets the amount of flush water used as makeup water in the first flush mode of the double flush mode to be less than the amount of flush water used as makeup water in the normal flush mode.

8. 2. The flush toilet of claim 1, wherein the control unit sets the amount of flush water used as makeup water in the first flush mode to 0.3 L or less in the double flush mode.

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