JPH0673640A - Method for controlling fluid pressure of fluid jet style loom and device therefor - Google Patents

Abstract

PURPOSE:To surely perform the picking operation of the loom even at the operation starting time of the loom to improve the state of the woven fabric. CONSTITUTION:A pressure control means 18 for controlling the pressure of a picking fluid fed into the picking nozzle 10 of the loom is disposed. A pressure-switching means 28 is also disposed, into which a stationary pressure setting signal for setting the pressure-setting value of the pressure control means 18 to a pressure setting value for the stationary operation of the loom and an starting pressure setting signal for setting a higher starting pressure setting value than the pressure setting value for the stationary operation are inputted. The output of the pressure-switching means 28 into the pressure control means is switched from the stationary pressure setting signal into the starting pressure setting signal at a prescribed time after the operation- starting time of the loom is inputted and before the early picking operation of the started loom is started. Further, the output of the pressure switching means 28 into the pressure control means is switched from the starting pressure setting signal into the stationary pressure setting signal at a prescribed time near to a time when the pressure of the fluid for the picking after the start of the loom begins to exceed the pressure of the fluid in the stationary operation of the loom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure control method and apparatus for a fluid jet loom that adjusts the pressure of fluid ejected from a fluid jet nozzle of a fluid jet loom.

[0002]

2. Description of the Related Art Conventionally, a fluid jet loom is generally provided with a pressure adjusting valve on the fluid pressure supply side in order to set an optimum fluid pressure for weft transportation during weft insertion. For this pressure adjusting valve, an electric pressure adjusting valve with a built-in pressure sensor is often used in order to perform pressure control by automatic control during the operation of the loom and always maintain an optimum weft transport state. This electric pressure control valve detects the pressure on the output side with a pressure sensor and feeds it back to the back pressure chamber on the input side, and uses the difference between the pressure on the input side and the pressure on the output side to open the regulating valve via a diaphragm. The pressure on the output side is adjusted according to the set pressure value.

Further, as disclosed in JP-A-4-185741, the fluid pressure for weft insertion is set to be slightly higher than the steady pressure during normal operation while the loom is stopped, and the pressure is maintained. There is also proposed a weft-insertion air pressure control method for returning to a steady pressure after a predetermined time after weaving. Further, as disclosed in Japanese Patent Laid-Open No. 61-152851, a device for weft-inserting a traction force of an air injection nozzle at a fluid injection pressure higher than that during normal operation for a predetermined time at restart, and a loom start-up. A device has been proposed in which a fluid is jetted in advance from a nozzle at a constant pressure before rear weft insertion.

[0004]

In the case where the former general electric pressure control valve of the above-mentioned conventional technique is provided, the weaving fluid is regularly consumed while the loom is stopped, and the steady state is maintained during the loom operation. Unlike the state, the fluid pressure for weft insertion is maintained at a predetermined set pressure in a state where the fluid is not consumed from the weft insertion nozzle. At this time, since there is no fluid consumption, the pressure regulating valve maintains a predetermined set pressure in a state where the opening degree of the valve is narrowed and narrowed as compared with the steady state during operation of the loom. Since the loom operates from this state and the weft insertion fluid starts to be consumed at the same time as weft insertion, there is a problem that the weft insertion fluid pressure decreases when the weaving machine is started. That is, fluid consumption starts at the same time as weft insertion, and the fluid pressure begins to decrease at the same time as weft insertion because the opening of the valve is narrowed. Even if the pressure is set to a predetermined value and the fluid pressure is feedback controlled by the electric pressure regulating valve, the decrease is transmitted to the sensor and the back pressure of the diaphragm is increased, and the valve opening is gradually increased for weft insertion. There is a response delay due to the transmission time of the pressure in each part until the fluid pressure is increased, and during that time, weft insertion is performed at a low fluid pressure. Therefore, when wefting was started at the start of the loom, the fluid pressure for wefting was low, and wefting errors were likely to occur.

Further, in the technique disclosed in the latter publication of the above-mentioned conventional technique, when weft insertion is started by setting the weft inserting fluid pressure at the time of starting the loom to a pressure higher than a steady state (Japanese Patent Laid-Open No. 185741/1992). (Gazette), the fluid pressure for weft insertion starts to decrease from the state of a high set pressure when the weft insertion starts as described above. Therefore, the weft yarn at the beginning of weft insertion is weft-inserted at a pressure higher than the steady state. As a result, problems such as weft breakage and fluffing occur at the beginning of weft insertion, and there is a drawback that defects are likely to occur in the woven fabric. Further, when the weft insertion fluid is jetted prior to the latter weft insertion of the above-mentioned conventional technique (Japanese Patent Laid-Open No. 61-152851), the weft is exposed to a fluid jet for a long time before weft insertion. The weft yarn made into the weft-inserting fluid has the drawback that problems such as weft breakage and fluffing occur similarly to the above, and defects are likely to occur in the woven fabric.

The present invention has been made in view of the above-mentioned problems of the prior art. Even at the beginning of the operation of the loom, weft insertion is surely performed and the fluid pressure control of the fluid injection type loom in which the condition of the woven fabric is good. It is an object to provide a method and a device.

[0007]

SUMMARY OF THE INVENTION According to the present invention, when a loom is started, a weft insertion nozzle of the loom is supplied at a predetermined time after the operation start signal of the loom is input and before the first weft insertion after the start of the loom. Change the pressure setting value of the weft inserting fluid pressure from the steady pressure setting value during steady operation to a higher starting pressure setting value, and then change the weft inserting fluid pressure to the fluid pressure during steady operation. This is a fluid pressure control method for a fluid injection loom that restores the starting pressure set value to a steady pressure set value at a predetermined time around the point of time when it starts to exceed the starting point.

Further, according to the present invention, a pressure control means for controlling the pressure of the weft inserting fluid supplied to the weft inserting nozzle of the loom is provided, and a steady pressure setting signal for steady operation of the loom and a higher pressure signal than this. The start-up pressure setting signal for start-up, which sets the pressure set value, is input, and after the operation start signal of the loom is input, at a predetermined time before the first weft insertion after the start of the loom, the pressure control means is The output is switched from the steady pressure setting signal to the starting pressure setting signal, and at a predetermined time around the time when the weft inserting fluid pressure after starting the loom starts to exceed the fluid pressure during steady operation, the above pressure A fluid pressure control device for a fluid injection loom, comprising pressure switching means for switching the output to the control means from the starting pressure setting signal to the steady pressure setting signal.

[0009]

The fluid pressure control method and apparatus for a fluid jet loom according to the present invention expects that the fluid pressure for weft insertion will decrease as the fluid is consumed after the first weft insertion after the start of the loom. In order to compensate for this, the set pressure value for the pressure control means is changed in advance to a pressure set value higher than that during steady operation at a predetermined time. Therefore, the pressure control means
The opening degree of the valve can be set large in order to increase the fluid pressure without relying on the feedback control having a large response delay by the built-in pressure sensor. Thus, when the loom is started, there is no large decrease in the fluid pressure at the nozzle portion, and no excessive fluid pressure is applied to the weft threads, so that weft insertion errors do not occur.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention. This embodiment relates to a fluid pressure control method and device for an air jet loom, and as shown in FIG. 3, a weft insertion nozzle 10 and a weft insertion nozzle, which are provided in a weaving machine (not shown) and through which a weft 11 is inserted. An air supply pipe 12 is provided, and an electromagnetic opening / closing valve 14 and an air tank 16 for intermittently injecting air at the time of weft insertion are provided in the middle of the air supply pipe 12, and a pressure adjusting means, which is a pressure control means, is provided. An air supply source 20 is connected via the valve 18. Pressure control valve 18
Is a known electric pressure control valve, which detects the output side pressure by a pressure sensor and feedback-controls the control valve so that the output side pressure becomes a predetermined value. A pressure control circuit 22 that sets the pressure to a predetermined value is connected to the pressure adjusting valve 18.

The pressure control circuit 22, as shown in FIG.
A flip-flop 24 in which an air injection signal which is an opening / closing signal of the electromagnetic on-off valve 14 is input to a set terminal and a loom stop signal is input to a reset terminal, a counter 26 whose output is input to a preset terminal, and a counter 26. The pressure switching circuit 28 is provided as a pressure switching means for switching the set pressure of the pressure regulating valve 18 by inputting the output of. The pressure switching circuit 28 includes a starting pressure setting signal for setting the output side pressure of the pressure regulating valve 18 at the time of starting the loom to a starting pressure setting value slightly higher than the pressure during steady operation, and the pressure during steady operation. The steady pressure setting signal for setting the steady pressure setting value is input. The air injection signal is applied to the AND circuit 30 at the count input terminal of the counter 26.
Is input through the AND circuit 30 and the counter 2
The output signal of 6 is also input. Further, the counter 26 is connected to a predetermined pick number setting device 32 that outputs a numerical value to be compared with the count value of the pulse number of the air injection signal. The predetermined pick number setter 32 sets the pick number which is the number of jets of the weft yarn corresponding to the pulse number of the air jet signal, and sets the number of picks a predetermined number of times after the loom is started.

In the fluid pressure control method for an air jet loom of this embodiment, an operation start signal is issued by an operation start button (not shown), and the loom operation signal is input to the loom as shown in FIG. When the operation is started, the air injection signal is issued at a constant timing in synchronization with the rotation of the loom in order to inject the weft insertion air. The air injection signal is input to the electromagnetic opening / closing valve 14 to start opening / closing of the valve, and is also input to the flip-flop 24 so that the output of the flip-flop 24 rises at the first rising edge of the air injection signal after the start of the loom operation. increase. Further, the air injection signal is also input to the counter 26 via the AND circuit 30. Here, the output of the counter 26 is also input to the AND circuit 30, and the counter 26 can start counting when the output of the flip-flop 24 becomes (H). At this time, the output of the counter 26 becomes (H ) Is set. Further, the set pick number of the predetermined pick number setting device 32 determines the time when the output of the pressure switching circuit 28 is switched from the starting pressure setting signal to the steady pressure setting signal, and is set to 5 here.

When the output of the counter 26 after the loom is activated becomes (H), first, the pressure switching circuit 28 is activated in place of the steady pressure setting signal in order to set the output side pressure of the pressure regulating valve 18 to be slightly higher. The pressure setting signal is sent to the pressure adjusting valve 18
To enter. At the same time, the counter 26 counts the air injection signal at its rising edge, and if the count number is less than 5, the output is maintained at (H). Then, when the count number of the counter 26 reaches 5, the output of the counter 26 drops to (L), and the pressure switching circuit 28 changes the output signal to the pressure adjusting valve 18 from the starting pressure setting signal to the steady pressure setting signal. Switch to and output.

As a result, the injection air pressure of the weft insertion nozzle 10 is set to a value higher than the steady pressure at the same time as the first weft insertion after the start of the loom. As described above, the actual injection air pressure at the nozzle 10 begins to decrease due to the start of injection, but the pressure increase due to the high air pressure set by the first air injection signal gradually appears. , The gradient of the pressure decrease can be suppressed to a small one. Here, the reason why the air pressure of the nozzle 10 does not become high at the same time as switching to high pressure by the starting pressure setting signal is due to the response delay of the control system, the pressure transmission time, and the like.

For comparison, FIG. 2 also shows a conventional injection air pressure decrease curve. According to this, at the same time as the first weft insertion of the loom, the pressure starts to decrease with a large inclination,
After that, the feedback control of the pressure regulating valve 18 works,
Although the pressure gradually returns to the steady pressure, it takes a long time to return to the steady pressure because the response delay time is too long. On the other hand, in this embodiment, the pressure set value of the pressure regulating valve is set in advance to the starting pressure set value higher than the steady pressure set value by the starting pressure setting signal without waiting for the pressure recovery by the feedback control. The gradient of the pressure decrease of the injection air pressure can be suppressed to a small one, and a large pressure decrease can be prevented. In addition, it is possible to restore the steady pressure early.

The timing at which the starting pressure setting signal is switched to the steady pressure setting signal is set in consideration of the time when the weft inserting fluid pressure starts to exceed the pressure during steady operation as a result of the high pressure setting by the starting pressure setting signal. The set pick number of the predetermined pick number setting device 32 is determined so that it is an appropriate time before and after this time point.

According to the method and apparatus for controlling the fluid pressure of the air jet loom of this embodiment, the jet air pressure does not decrease at the time of weft insertion at the start of the loom, and weft insertion errors do not occur. Therefore, good weaving is always possible.

Next, a second embodiment of the present invention will be described with reference to FIG.
A description will be given based on FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment uses a timer 36 instead of the counter of the first embodiment.
Is provided. In addition, the starting pressure setting signal for setting the pressure slightly higher than the pressure during steady operation is independently supplied from the control unit (not shown) as in the first embodiment.
8, the steady pressure setting signal is input to the pressure switching circuit 28 through the multiplier 38, and the steady pressure setting signal and the steady pressure setting signal are set to a predetermined multiple, for example, 1. A starting pressure setting signal having a value obtained by multiplying 1 to 1.2 may be input to the pressure switching circuit 28.

The fluid pressure control method for the air jet loom of this embodiment is the same as that of the first embodiment, except that the starting pressure set value set higher at the start of the loom is set to the steady pressure set value during steady operation. The timing for returning to (1) is set to a fixed time by the timer 36, and the predetermined time is set to the timer 36 from the predetermined time setter 38. This fixed time is set to the time required for the injection air pressure from the nozzle 10 to approach the set pressure in the operating state, as in the first embodiment.

Next, the third embodiment of the present invention will be described with reference to FIGS.
It will be described with reference to FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the starting pressure setting signal in the first and second embodiments is changed stepwise, and the steady pressure setting signal is input to the pressure switching circuit 28 via the adder 40. It is the one. A predetermined curve generator 42 is connected to the adder 40 to increase the injection air pressure through a predetermined curve or step.

As shown in FIG. 7, the predetermined curve generator 42 includes a counter 44 that is preset by a loom stop signal and counts the rising edge of the air jet signal, and a memory 46 whose address is designated by the count output of the counter 44. The pressure addition amount recorded in the designated address of the memory 46 is input to the adder 40.

The amount by which the set pressure is changed is such that the air pressure decreases at the same time as the air injection when the loom is started at the steady pressure when the loom is started, and then changes to the air pressure until the set pressure is restored during the steady operation. On the other hand, a complementary value of increasing pressure may be set, and as shown in FIG. 8, the increasing pressure may be gradually increased. The timing of this gradual change may be changed by an air injection signal, or may be changed more finely at a predetermined timing according to the crank angle of the loom or the like, and may be changed by a smoother curve.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
A description will be given based on FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the set signal input to the set terminal of the flip-flop 24 in the first embodiment is replaced with an air injection signal and used as a predetermined timing signal. This predetermined timing signal is a signal that is issued after the loom is started and before the first air injection signal is issued. For example, as shown in FIG.
A predetermined angle between 0 ° and 90 ° at which the air injection signal is output, for example, is output at every 0 °. The setting of the predetermined angle is a timing to compensate for this by considering the response delay from when the starting pressure setting signal for setting the pressure higher than the steady pressure is issued until the pressure of the nozzle 10 actually starts to be increased. At the beginning of the first air injection, the period is such that the actual air pressure at the nozzle portion does not become higher than the steady operating pressure, which is earlier than the first air injection signal. The timing for switching the starting pressure setting signal to the steady pressure setting signal for the pressure regulating valve is the same as in the first embodiment.

As a result, the output of the counter 26 becomes (H) at a predetermined timing prior to the first air injection signal after the start of the loom, and the start pressure setting signal also becomes (H) at the same time. It is output to the pressure control valve and set to a higher pressure than during steady operation. Then, the pressure at the nozzle 10 actually starts to increase slightly after this setting switching due to the response delay, and at this time, the first air injection signal after the start of the loom is issued, and the pressure drop due to the air injection is suppressed. It is a thing.

According to this embodiment, the air pressure supplied to the nozzle 10 is adjusted to be high by the first weft insertion time after the start of the loom, and the pressure becomes high at the time of actual jetting. Therefore, it is possible to surely prevent a decrease in jet air pressure at the time of starting the loom without delay in response, and to prevent unnecessary air pressure from being applied to the weft.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
1, it demonstrates based on FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment is similar to the first embodiment except that the flip-flop 2
The set signal input to the set terminal of No. 4 is replaced with an air injection signal, and is replaced with a signal delayed by a certain time t with respect to the rising edge of the loom operation signal. Flip flop 24
It is connected to the set input terminal of. The delay amount t of the output signal of the timer 50 with respect to the loom operation signal is actually the nozzle 10 after the start pressure setting signal for setting the injection air pressure to a pressure higher than the steady pressure is issued, as in the fourth embodiment. Consider the response delay until the pressure starts to increase. That is, the timing at which the output of the timer 50 rises is a predetermined time preceding the first air injection after the loom is started by the above-mentioned response delay, and the actual air pressure in the nozzle 10 is in steady operation at the first air injection timing. It is earlier than the first air injection signal, for a period that does not exceed the pressure. The timing of switching from the starting pressure setting signal to the steady pressure setting signal is the same as in the first embodiment.

As a result, the timing at which the output of the counter 26 becomes (H) is set at a predetermined timing prior to the first air injection timing after the start of the loom, and the counter output of the starting pressure setting signal also becomes (H). At the same time, the pressure is output to the pressure control valve, and the pressure is set higher than that during steady operation. Then, the pressure at the nozzle portion actually starts to increase slightly after the setting switching timing due to the response delay, and at this time, the first air injection signal after the loom is started is issued, and the pressure drop due to the air injection occurs. It can be suppressed. Incidentally, in order to input the count signal to the counter 26, the air injection signal is input to the counter 26 via the AND circuit 30 as in the first embodiment. As a result, the pressure setting signal to the pressure regulating valve 18 is switched from the starting pressure setting signal to the steady pressure setting signal by the pressure switching circuit 28 by the output signal of the counter 26, as in the first embodiment.

Also in this embodiment, the air pressure supplied to the nozzle 10 is adjusted to be high by the first weft insertion time after the start of the loom, and the pressure is not high at the time of actual jetting. Since it does not exist, it is possible to reliably prevent a decrease in the injection air pressure at the time of starting the loom without delay in response. The timer 50 may be any one as long as it delays the loom operation signal for a predetermined time, and a delay circuit other than the timer may be provided. Furthermore, even if one of the loom operating signal and the loom stop signal is input to the timer 50 or the flip-flop 24, the same signal is input to the flip-flop 24 or the timer 50 input to the other via the inverter. good.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
3, it demonstrates based on FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment is similar to the first embodiment except that the flip-flop 2
The set signal input to the set terminal of No. 4 is replaced with the air injection signal, and the rising edge of the operation start signal by the loom operation start button 52 is input through the first timer 54 which delays for a predetermined time t _1. Is. further,
The operation start signal is directly input to the reset terminal of the flip-flop 24. Further, this operation start signal is
_A loom operating signal is input to a timer 56 that delays t ₂ time longer than _1, and a loom operating signal is input to a motor drive circuit of a loom (not shown) t ₂ hours after the operation start button 52 is pressed.

[0030] The delay time t _1, t ₂ is, t ₂ -t ₁ is the similar to the fourth embodiment, since the activation pressure setting signal for setting the above constant pressure the pressure is issued, actually air The period is set in consideration of the response delay until the pressure of the injection nozzle 10 starts to be increased. That is, the first timer 5
The output of No. 4 rises before the output of the second timer 56 rises and the first air injection signal is output after the loom is started. At the first air injection timing, the actual air pressure at the nozzle section becomes steady. It is an early time so that it does not become higher than the operating pressure. The timing of switching from the starting pressure setting signal to the steady pressure setting signal is the same as in the first embodiment.

Also in this embodiment, the air pressure supplied to the air injection nozzle is adjusted to be high by the first weft insertion time after the start of the loom, and the pressure becomes high at the time of actual injection. Therefore, it is possible to reliably prevent a decrease in the injection air pressure at the time of starting the loom without delay in response. The timers 54 and 56 are
Anything that delays the loom operation signal for a predetermined time may be used,
A delay circuit other than the timer may be provided.

The fluid jet loom to which the present invention is applied may be one in which air is jetted and weft is inserted, and water is also jetted and weft is inserted. In addition to the time and the number of picks as described above, the timing for switching the starting pressure setting signal at the beginning of the loom operation to the steady pressure setting signal is actually set by providing a pressure sensor between the weft insertion nozzle and the electromagnetic on-off valve. The injection pressure may be switched when the injection pressure exceeds a predetermined pressure value. As the predetermined pressure value, the steady pressure set value by the steady pressure setting signal can be used as it is, or a value obtained by adding a predetermined offset amount thereto can be used. Further, the weft insertion nozzle of the present invention is meant to include not only the main nozzle but also a sub nozzle arranged in the warp opening. Further, the predetermined timing for outputting the starting pressure setting signal does not necessarily have to be set before the time point at which the first air injection signal after the loom is started is output, and the initial air injection signal after the loom is started. May be issued, for example, at a time when the drop in the injection air pressure does not decrease significantly, and may be set at a time after one or more air injection signals have been output after the loom is started.

[0033]

The method and apparatus for controlling the fluid pressure of the fluid jet loom according to the present invention, when the first weft insertion after the loom is started,
Since the pressure set value, which is the control target value of the pressure control means, is set to be high for the predetermined period after the first weft insertion, it is possible to prevent the air pressure from decreasing when wefting is started after the weaving machine is started. You can eliminate mistakes. Moreover,
It is not set high since the first weft insertion,
At the beginning of the first weft insertion, the pressure is steady, and the pressure is set to be high so as to compensate for the pressure drop due to the weft insertion. Therefore, good weaving is possible without applying excessive fluid pressure to the weft. Also, by adjusting the air pressure supplied to the nozzles to a high value prior to the first weft insertion time after the loom is started, it is possible to reliably prevent a drop in the injection air pressure when the loom is started without a response delay. You can do it.

[Brief description of drawings]

FIG. 1 is a block diagram of a fluid pressure control device for a fluid jet loom according to a first embodiment of the present invention.

FIG. 2 is a time chart showing changes in the injection air pressure in the first embodiment.

FIG. 3 is a circuit diagram of a fluid pressure control device for the fluid jet loom according to the first embodiment.

FIG. 4 is a block diagram of a fluid pressure control device for a fluid jet loom according to a second embodiment of the present invention.

FIG. 5 is a partial block diagram of a fluid pressure control device for a fluid jet loom according to a second embodiment.

FIG. 6 is a block diagram of a fluid pressure control device for a fluid jet loom according to a third embodiment of the present invention.

FIG. 7 is a block diagram of a predetermined curve generator according to a third embodiment.

FIG. 8 is a polygonal diagram showing changes in the injection air pressure of the third embodiment.

FIG. 9 is a partial block diagram of a fluid pressure control device for a fluid jet loom according to a fourth embodiment of the present invention.

FIG. 10 is a time chart showing the operation of the fluid pressure control device for the fluid jet loom according to the fourth embodiment.

FIG. 11 is a partial block diagram of a fluid pressure control device for a fluid jet loom according to a fifth embodiment of the present invention.

FIG. 12 is a time chart showing the operation of the fluid pressure control device for the fluid jet loom according to the fifth embodiment.

FIG. 13 is a partial block diagram of a fluid pressure control device for a fluid jet loom according to a sixth embodiment of the present invention.

FIG. 14 is a time chart showing the operation of the fluid pressure control device for the fluid jet loom of the sixth embodiment.

[Explanation of symbols]

 10 nozzles 18 pressure regulating valve 22 pressure control circuit 24 flip-flop 26 counter 28 pressure switching circuit

Claims (3)

[Claims] 1. A fluid pressure control method for a fluid jet loom, comprising a pressure control means for controlling the pressure of a weft inserting fluid supplied to a weft inserting nozzle of the loom. At a predetermined time after the input and before the initial weft insertion after the start of the loom, the pressure set value which is the control target of the pressure control means is set to a higher starting pressure set value than the steady pressure set value during the steady operation. After that, the starting pressure set value is returned to the steady pressure set value at a predetermined time around the time when the weft inserting fluid pressure starts to exceed the fluid pressure during steady operation. Fluid pressure control method for a fluid jet loom. 2. The predetermined time after inputting the operation start signal of the loom is after the pressure setting value is changed until the pressure at the nozzle portion actually starts to rise after the first weft insertion start time after the loom is started. 2. The fluid pressure control method for a fluid jet loom according to claim 1, wherein the fluid pressure control method is set at an earlier timing by a predetermined period within the response delay period. 3. A pressure control means for controlling the pressure of the weft insertion fluid supplied to the weft insertion nozzle of the loom, and the pressure set value of the pressure control means is set to a pressure set value for steady operation of the loom. The steady pressure setting signal and the starting pressure setting signal that is set to a value higher than this for the starting pressure setting value are input, and after the input of the loom operation start signal, the initial weft insertion after the loom is started. At the previous predetermined time, the output to the pressure control means is switched from the steady pressure setting signal to the starting pressure setting signal, centering around the time when the weft insertion fluid pressure after starting the loom begins to exceed the fluid pressure during steady operation. At a predetermined time before and after this, a pressure switching unit that switches the output to the pressure control unit from the starting pressure setting signal to the steady pressure setting signal and outputs the pressure. Loom fluid pressure The control device.