JPS6016585Y2 - Transport article detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conveyed article detection device that uses ultrasonic waves to detect whether copy paper is being conveyed normally in a copying machine, for example, and will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an article such as copy paper, which is conveyed along the upper surface of a guide plate 2 from one side to the other.

Reference numeral 3 denotes a detection device disposed at key points on the guide plate 2. For example, as shown in FIG. The ultrasonic transmitter has a structure in which a lid 4d is attached with a pair of terminals 4c, 4c implanted in the opening of the case 4a and electrically connected to the piezoelectric element, and sealed via a vibration absorbing layer 4e such as a sponge. A wave transducer 4 and an ultrasonic wave receiver 5 having the same structure are provided so as to face each other, and the guide plate 2 is positioned between them.

The guide plate 2 is provided with a through hole 2a at a position on a line connecting the centers of the transmitter and receiver 5, through which the ultrasonic waves radiated from the transmitter 4 are transmitted and received by the receiver 5. It will be done.

Although not shown, an oscillation circuit that excites the wave transmitter 4 is connected to the wave transmitter 4 side, and an article 1 conveyed along the guide plate 2 blocks the through hole 2a and transmits waves to the wave receiver 5 side. Needless to say, a detection circuit is connected to detect the article 1 when the ultrasonic waves from the device 4 are cut off.

However, the inventors of the present invention have found that such an article detection device using ultrasonic waves has the following problems.

In other words, when the article is not being conveyed along the guide plate, the ultrasonic waves emitted from the transmitter are received by the receiver through the through holes in the guide plate, and when the article is being conveyed, the ultrasonic waves emitted from the transmitter are received by the receiver. It is desirable to block the sound waves so that they are not received by the receiver, but experiments have shown that when an article is not conveyed due to an inappropriate distance between the guide plate and the transmitter, the transmitter may be blocked by the ultrasonic wave. There was a problem that the sensitivity was poor and malfunctions occurred.

This proposal was made to deal with this problem, and it is possible to maintain high sensitivity and operate accurately and stably by positioning the guide plate at a distance corresponding to approximately half a wavelength integer multiple of the length from the transmitter. The present invention provides an article detection device capable of detecting objects.

Now, both the ultrasonic transmitter 4 and the receiver 5 are connected to the second
A plate having the same dimensions and structure as shown in the figure and the characteristics shown in the table below was prepared.
Using a stainless steel plate measuring 0TrrIrL x width 200TIrIrL x 0.6 mm thick with a through hole 2a of diameter 15 mm in the center, the two transducers 4 and 5 were connected to 3
They were installed at a distance of 1 □ of 5 mm, and a guide plate 2 was inserted between them, and the relationship between the distance 11 of the guide plate from the transmitter and the sensitivity at that position was measured. The results are shown in Figure 3. Shown in the graph.

As clearly shown in Figure 3, by placing the guide plate at a distance from the transmitter that corresponds to approximately 12 mm or an integer multiple thereof, the sensitivity of the receiver can be maintained. The effect of the present invention can also be understood from the fact that high sensitivity can be maintained.

Therefore, according to the present invention, it is possible to provide an article detection device that can stably and reliably detect articles being conveyed along the guide plate without malfunction.

In the graph, the sensitivity on the vertical axis is the sensitivity of the transmitter 4 when the resonant frequency is 33.
It is expressed as a voltage value induced on the receiver side when driven at 5 kHz and an input of 0.3 W.

Further, the distance 1□ on the horizontal axis is shown in terms of the sound wave input from the transmitter.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of the conveyed article detection device used to explain the present invention, Figure 2 is a sectional view showing an example of the structure of an ultrasonic transmitter (receiver) used in the present invention, and Figure 3 is a It is a graph which shows the relationship between the sensitivity of a wave receiver and the distance between a wave device and a guide plate. 1... Conveyed article, 2... Guide plate, 2
a...Through hole, 4...Ultrasonic transmitter, 5
...Receiver.

Claims (1)

[Scope of utility model registration request] An ultrasonic transmitter and an ultrasonic receiver are provided on both sides of a guide plate that conveys articles from one side to the other, and the ultrasonic wave irradiated from the transmitter is received by the receiver on the guide plate. In an apparatus in which an article is detected by drilling a through hole to cause waves and blocking the article conveyed along the guide plate to block ultrasonic waves, the guide plate is used to transmit waves. 1. A detection device for a conveyed article, characterized in that the device is positioned at a distance approximately equal to an integer of half wavelengths from a container.