JPS6031728B2 - Intermittent drive device for endless belt in automatic screen printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intermittent drive device for an endless belt in an automatic screen printing machine, and more particularly, despite the non-uniformity of the mechanical properties of the endless belt due to thickness errors and other factors. , relates to an intermittent drive device that further improves the feeding accuracy of an endless belt.

As an intermittent driving device for an endless belt for textile printing using a DC motor, as already disclosed in Japanese Patent Laid-Open No. 54-34483 (Japanese Patent Publication No. 55-124427), a DC motor for intermittent driving an endless belt; A switch for converting and setting the repeat length of the endless belt into the number of pulses, a pulse generator for detecting the actual feed length of the endless belt as the number of pulses in response to the displacement of the endless belt, and the detection mechanism. A digital display that directly displays the detected repeat length in numbers, a digital control mechanism for generating a start/acceleration signal, a constant speed signal, and a deceleration/stop signal in response to the pulse number setting by the switch; The digital control mechanism includes a motor control mechanism for controlling input to the DC motor based on signals from the digital control mechanism to start, accelerate, drive at constant speed, decelerate, and stop the DC motor. There is known a device equipped with a calculation mechanism that subtracts the number of detected pulses from the set number of pulses and generates a deceleration signal so as to stop the belt at a beat length corresponding to the set number of pulses.

Although this intermittent drive device has excellent mechanical feed accuracy, since a normal endless belt is made of reinforcing rubber and is not a rigid body, feed errors caused by the endless belt itself are unavoidable. Become something.

In other words, the feeding error of this endless belt is not due to thickness error or other factors, but is also due to non-uniformity of mechanical properties, and especially during intermittent feeding, differences in the amount of elongation at each start and stoppage. This is due to the difference in the degree of shrinkage.

Furthermore, when driving only the inner tension side roller of a pair of support rollers and starting driving the entire endless belt at once from a stopped state, as is commonly done in the past, tension is concentrated on the tension side of the endless belt. This is also the biggest factor in the feed error. The purpose of the present invention is to disperse the concentration of tension at the start of the endless belt, and to improve the feeding accuracy of the endless belt despite the non-uniformity of the thickness of the endless belt and the non-uniformity of the mechanical properties caused by other factors. An object of the present invention is to provide an intermittent drive device for an endless belt in an automatic screen printing machine that can increase the speed of printing.

According to the present invention, a pair of rollers, an endless belt supported by the rollers, a DC motor for intermittently driving the rollers, and a repeat length of the endless belt are converted and set to the number of pulses, and the actual feeding of the endless belt is performed. An automatic control mechanism comprising a control mechanism that detects the length as a pulse number and subtracts the detected pulse number from the set pulse number to decelerate and stop the DC motor so as to correspond to the set pulse number or stop the belt at the beat length. In an intermittent drive device for an endless belt in a screen printing machine, each of the tension side roller and delivery side roller that supports the endless belt is driven by a DC electric motor that can be driven individually, and the actual feeding of the endless belt is controlled in response to the displacement of the rollers. A pulse generator that detects the length as the number of pulses, and a digital servo mechanism that decelerates and stops the DC motor by subtracting the number of detected pulses from the set number of pulses to correspond to the set number of pulses or stop the belt at the beat length. 2.
between two pulse generators and at least one digital servo mechanism, the number of detected pulses from the pulse generator of the pulling side roller is compared with the number of detected pulses from the sending side pulse generator, and the number of detected pulses from the pulse generator of the pulling side roller is compared and the number of detected pulses is sent to the electric motor according to the deviation. A deviation comparison counter is provided to correct and control the input, so that there is no difference in position between the two rollers at any moment during startup, running, deceleration, or any mode, so that the endless belt does not have to be driven. An intermittent driving device for an endless belt using two electric motors is provided, which is characterized in that no tension is applied.

The present invention will be explained below based on specific examples shown in the accompanying drawings.

In FIG. 1, an endless belt 3 is stretched between a pair of rollers, that is, a tension side roller and a delivery side roller 2, and this endless belt 3 is intermittently fed by a repeat length P. Printed fabric 2
0 by means known per se.

That is, a gluing device 16 for applying glue to the belt 3 is provided close to the feed-out roller 2, and a pasting press roller 7 is provided above the feed-out roller 2 so as to sandwich the endless belt 3 therebetween. is located. Printed cloth 2 rivers,
It is supplied between the press roller 7 and the belt 3 and pasted onto the belt 3. The endless belt 3 is intermittently fed by a predetermined repeat length, and the screen 4 provided on the upper running path of the belt 3 is lowered onto the fabric to be printed 20.
A screen (not shown) scans and moves to apply the colored paste on the screen onto the fabric to be printed, the screen 4 rises, and this cycle is repeated for a predetermined number of colors, thereby completing the printing operation. The printed cloth 20' is peeled off from the endless belt 3 and sent to other facilities such as a dryer. (Mangle)
19 and the above cycle is repeated. In the intermittent drive device of the present invention, the tension side roller is connected to a DC motor 5-1 for driving the roller via a speed reducer 6-1 as necessary, and the delivery side roller 2 is connected to a DC motor 5-1 for speed reduction as necessary. Direct current motors 5-2 for driving the rollers are provided via motors 6-2, respectively.

In addition, these driving rollers and 2 are equipped with a device to detect the actual feeding length of the endless belt 3 on the pulling side and the feeding side in accordance with the displacement of the rollers and 2, respectively.
Pulse generators 12-1 and 12-2 are provided so as to be driven and rotated by rollers and 2 without slipping, for example, via a gear mechanism (not shown) or the like.

The pulse generators 12-1 and 12-2 may also be used by being directly connected to the rear of the motor. Furthermore, there is a beat length setting switch 7 that sets and displays the repeat length of the endless belt, and a pulse conversion mechanism (sequence calculation circuit) that converts the set or beat length into the number of pulses.
8 is provided, and each of the pulling side roller 1 and the sending side loaf 2 is set by subtracting the set number of pulses from the mechanism 8 and the number of detected pulses from the pulse generators 12-1 and 12-2. DC motors 5-1 and 5 are used to stop the belt at a beat length corresponding to the number of pulses.
A series of digital servomechanisms 9-1, 1 to stop 1-2
0-1, 11-1 and 9-2, 10-2, 11-2 are provided, respectively.

In the specific example shown in FIG.
It consists of 1-2. That is, the set number of pulses from the aforementioned pulse variable f depth mechanism 8 is transmitted through the wirings 21-1, 21-2, and the number of detected pulses from the pulse generators 12-1, 12-2 is transmitted through the wirings 15-1, 15-2. and wiring 22-
1, 22-2 to deviation counters 9--, 9-2, respectively, where a subtraction operation is performed between the set number of pulses and the number of detected pulses. The calculated pulses from the counters 9-1 and 9-2 are converted into voltages by the digital-to-analog converters 10-1 and 10-2, and this voltage signal is converted into a voltage signal by the motor control mechanism 11-2.
A predetermined electrical input is supplied to the motors 5-1, 5-2 through wiring 23-1, 23-2 in order to decelerate and stop the motors 5-1, 5-2 at a set number of pulses. sent to. The DC motors 5-1 and 5-2 have tacho generators 13-1 and 13 that detect the actual rotational speed of the motors.
-2 is provided, and this tacho generator 13-1,
The detection signal from 13-2 is fed back to the motor control mechanism through wires 24-1 and 24-2. The relationship between the detection pulse and the setting pulse and the operation of the digital control mechanism and the prime mover based thereon will be explained with reference to the time charts in Figures 2-A to 2-D.

Figure 2-A shows the calculated pulses, Figure 2-B shows the voltage generated by the digital/analog converter, Figure 2-C shows the input to the motor, and Figure 2-D shows the belt feed. be. First, the difference between the number L of pulses set as the repeat length by the switch 7 and the pulse conversion mechanism 8 and the number R of detected pulses from the pulse generators 12-1 and 12-2 is calculated as follows:
Calculations are performed by deviation counters, that is, calculation units 9-1 and 9-2.

As shown in FIG. 21A, the number of calculated pulses LR increases rapidly as the motor starts to be driven, and decreases in inverse proportion to the rotation time of the motor.

This calculation pulse number LR is calculated by the digital/analog converter 1.
0-1, 10-2 and is changed into a voltage, but in order to prevent the motor from running out of control, its maximum value is suppressed to a constant value, as shown in FIG. 2-B.

The generated voltage in this case becomes an exponential function curve E as shown in Figure 2-B, which takes a long time and makes accurate control difficult. Convert.

Such curve conversion can be performed, for example, by the motor control mechanism 11-1.
, 11-2 built-in function conversion device (not shown)
In this way, a command voltage as shown in FIG. 2-C is applied to the DC motors 5-1 and 5-2.

This type of motor control mechanism is known per se; for example, the DOSP type digital DC servo manufactured by Japan Reliance Co., Ltd. or the position pack DC manufactured by Yaskawa Electric Co., Ltd.
Easily available as a servo. Thus, the rotation of the electric motor, i.e. the feed of the belt, follows the line A-B-C shown in Figure 2-D.
-D, that is, the acceleration drive section AB, the constant velocity drive section C, and the deceleration drive section CD.

Also, following this belt feeding stroke, the belt resting stroke DA
The entire process constitutes one printing process of the printing machine. Further, in FIG. 2-D, the area surrounded by ABCD corresponds to the belt feeding length. In the present invention, the DC motors 5-1 and 5-2 are driven after confirming that the screen frame 4 is in the raised position.

For this purpose, for example, a protrusion or the like is provided on a lifting drive mechanism (not shown) provided below the screen frame 4, and this protrusion or the like is detected by a limit switch when the screen frame 4 is in the raised position. The detection signal of the limit switch is transmitted to the DC motors 5-1, 5- through the motor control mechanism.
2 may be driven. It will thus be appreciated that in accordance with the present invention, intermittent feeding of the belt is effectively achieved.

According to the present invention, the above-mentioned digital servo mechanism, pulse generator, and DC motor are provided on each of the rollers on the sending side and the pulling side, and the detected pulses from both pulse generators are compared and the deviation is detected. The input to the DC motor is controlled accordingly.

For this purpose, in the specific example shown in FIG. In addition to direct feedback, the detection signal from the pulse generator 12-2 on the sending side is connected to the wiring 15-2 and 25-2, and the pulse generator 1 on the pulling side.
The detection signal from 2-1 is supplied to the deviation comparison counter 14 through wiring 15-1 and 25--, and the deviation comparison counter 14 compares the numbers of both detection pulses and converts the deviation into a correction voltage. This correction voltage is supplied to the motor control mechanism 11-2 on the sending side through the wiring 26.

That is, this deviation comparison counter 14 counts the number of pulses from the sending-side pulse generator 12-2 and the number of pulses from the pulling-side pulse generator 12-1, and compares the number of pulses on the sending side with respect to the number of pulses on the pulling side. As soon as there is a change in the motor control mechanism 11-2 on the delivery side,
The gate signal to the motor 5-2, and therefore the electrical input to the motor 5-2, is controlled so that the number of pulses detected by both pulse generators 12-1 and 12-2 is always the same. Now, if the tension side roller and the delivery side roller 2 are driven separately, even if the feed length of roller 1 and the feed length of roller 2 are equal, as shown in FIG.
Time velocity diagram ABCD of the tension side roller 1;
Time velocity diagram ABC'D of delivery side roller 2
' are often different (however, area ABCD=
area AB'C'D').

However, if the time-velocity diagrams of the tension side roller 2 and the delivery side roller 2 differ, even if the overall feed length is the same, abnormal stress will act on the endless belt, making it difficult to accurately feed the belt. It becomes difficult to ensure accuracy.

On the other hand, according to the present invention, the deviation comparison counter 1
4, the deviation between the number of detected pulses on the sending side and the number of detected pulses on the pulling side is detected moment by moment and the input to the motor is corrected. Control is performed so that not only the feed length (feed length) but also the shape match. for example,
In Fig. 3, if the deviation in the feeding length of both rollers, that is, the deviation in the area after t time from the start of feeding, is △x, then the number of pulses corresponding to △x is added to the feed roller 2 side. It is a correction. Of course, this correction is not performed all at once after the elapse of time t, but is performed moment by moment in units of one pulse. According to the present invention, in this way, the tension side roller and the delivery side roller 2 are driven by two separate electric motors, and the number of detected pulses is subtracted from the set number of pulses, and the number of pulses corresponding to the set number of pulses is calculated. By stopping the electric motor, comparing the number of pulses detected from the loaf on the pulling side and the number of pulses detected from the feeding roller, and controlling the input to the electric motor according to the deviation, the endless belt can be It is possible to avoid applying excessive tension or abnormal stress locally, reduce or suppress elongation and compression of the belt, and maintain overall feeding accuracy at a significantly high level.

Normally, the number of pulses for the repeat length can be 0.005 legs/1 pulse to 0.1 willow/1 pulse, while the precision of comparison and correction in the deviation comparison counter 14 can be 1 pulse.

The level of the correction electric signal from the deviation comparison counter 14 can be freely adjusted using a variable resistor (not shown) to match the capacity of the motor. In addition, in the specific example of the drawing, the tension side roller is used as the main roller, the delivery side roller 2 is used as the subordinate, and the drive of the delivery side roller is compared and corrected based on the number of pulses emitted from the tension side roller. It will be clear that the above-described features of the invention can also be achieved by adopting the opposite configuration.

Furthermore, the capacity distribution of the DC motors 5-1 and 5-2 is optimally selected depending on the size of the printing machine, the intermittent feed load of the endless belt, the fabric tension, and other loads. , for example, by driving only one of them in the normal manner 7. If Melon W needs it, divide it into two equal parts 3.
It is also possible to use two 7KW units, and the tension side can be set to 5. Shoes W, sending side 2. It is also possible to use a fox W.

Of course, it is necessary that the diameters of the tension side roller 1 and the delivery side roller 2, the rotation ratio of the respective pulse generators 12-1, 12-2, and the number of pulses are exactly the same. The machining dimension difference is the deviation counter 9-1, 9-2.
Within this range, fine correction adjustment is possible, for example, by F/F conversion (frequency conversion).

[Brief explanation of the drawing]

FIG. 1 is a side layout view of an intermittent driving device for an endless belt according to the present invention, and FIG. 2-A, FIG. 2-B, and FIG.
Figure -C and Figure 21○ are time charts showing the calculated pulses, the voltage generated by the digital-to-analog converter, the input to the motor, and the feeding of the belt, respectively, and Figure 3 shows the tension side roller and the delivery side roller. is a time-velocity diagram of Reference number 1 is the tension side roller, 2 is the delivery side roller,
3 is an endless belt, 5-1 and 5-2 are DC motors, 7 is a repeat length setting switch, 8 is a pulse conversion mechanism,
9-1 and 9-2 are deviation counters, 10-1 and 10
-2 is a digital analog converter, 11-1 and 11-2
12-1 and 12-2 are pulse generators, and 14 is a deviation comparison counter. Figure 3: Ship Figure 2-A Figure 2-B Figure 2-C Figure 2-D

Claims (1)

[Claims] 1. A pair of rollers, an endless belt supported by the rollers, a DC motor for intermittently driving the rollers, and a repeat length of the endless belt is converted and set to the number of pulses, and the actual An automatic control mechanism comprising a control mechanism that detects the feed length as a number of pulses, subtracts the detected number of pulses from the set number of pulses, and decelerates and stops the DC motor so as to stop the belt at a repeat length corresponding to the set number of pulses. In an intermittent drive device for an endless belt in a screen printing machine, each of the tension side roller and delivery side roller that supports the endless belt is
A DC motor that can be driven individually, a pulse generator that detects the actual feed length of the endless belt as a number of pulses in response to the displacement of the rollers, and a set number of pulses by subtracting the number of detected pulses from the set number of pulses. A digital servo mechanism that decelerates and stops the DC motor so as to stop the belt at a repeat length of A deviation comparison counter is installed between the two rollers to compare the number of pulses detected by the pulse generator on the sending side and to correct the input to the motor according to the deviation. An intermittent driving device for an endless belt using two electric motors, characterized in that no difference in position occurs at any moment in either mode, and therefore no tension is applied to the endless belt for driving. 2. The digital servo mechanism includes a deviation counter that subtracts the number of detected pulses from the set number of pulses, a digital-analog converter that converts the calculated pulses from the deviation counter into voltage, and a voltage signal from the digital-analog converter to set the motor. 2. The apparatus according to claim 1, comprising a motor control mechanism that controls the motor to be stopped at a certain number of pulses, and wherein said deviation comparison counter converts the deviation between the two numbers of pulses into a correction voltage signal and supplies it to the motor control mechanism.