JPS604137Y2 - Ultrasonic sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ultrasonic sensors, particularly those used in places where usage conditions are not favorable, such as paper sensors in copying machines and the like.

Conventionally, as shown in FIG. 1, the above-mentioned paper sensor in a copying machine has an ultrasonic microphone 3 and an ultrasonic speaker 4 disposed facing each other with a conveyance path 2 for the detected paper 1 in between. The receiving circuit 6 detects that the detected paper 1 blocks the ultrasonic waves 5 directed from the ultrasonic microphone 3 toward the ultrasonic microphone 3, and provides a paper detection signal 8 to a control section 7 of the copying machine.

9 is an oscillation circuit.

In this case, toner from the copying machine may fall onto the ultrasonic speaker 4 located below the conveyance path 2, staining the ultrasonic speaker 4 and causing a decrease in sensitivity. A filter 10 is attached to the ultrasonic speaker 4, and this filter 10 is replaced periodically to prevent a decrease in sensitivity.

However, there is a concern that the filter 10 may need to be replaced frequently depending on the amount of use of the copying machine.

Furthermore, since it is used in a narrow housing, there is a problem in that the ultrasonic waves 5 emitted from the ultrasonic speaker 4 are reflected by the surrounding photosensitive drums and rollers, resulting in reflected waves that may cause malfunctions. This is the current situation.

Therefore, the present invention was developed in order to avoid the problems of ultrasonic sensors used in places where the usage conditions are not favorable, and one embodiment of the present invention will be explained below based on FIG. 2. do.

Reference numeral 11 denotes an ultrasonic reflection horn, which is placed opposite the ultrasonic speaker 4 across the conveyance path 2 of the paper 1 to be detected. The ultrasonic reflecting horn 11 is disposed in between and facing the ultrasonic reflecting horn 11 .

With this configuration, the sound waves 5 emitted downward from the ultrasonic speaker 4 toward the ultrasonic reflection horn 11 are reflected by the ultrasonic reflection horn 11 and enter the ultrasonic microphone 3.

Both the ultrasonic speaker 4 and the ultrasonic microphone 3 are disposed toward the ultrasonic reflecting horn 11 side, and the ultrasonic speaker 4
Although the ultrasonic microphone 3 and the ultrasonic microphone 3 are not disposed facing each other as in the conventional case, the passage of the paper 1 to be detected can be detected.

Moreover, although toner from the copying machine falls onto the ultrasonic reflection horn 11, since the ultrasonic microphone 3 is facing downward, there is no need to worry about toner adhering to the ultrasonic microphone 3.
There is no need to mount the filter 10, which was conventionally required.

Furthermore, even if a certain amount of toner accumulates on the ultrasonic reflection horn 11, the reflectance decreases only slightly due to this, so cleaning and other operations are unnecessary for a considerably longer period than the period of replacing the conventional filter 10. .

Furthermore, by employing the ultrasonic reflecting horn 11, the ultrasonic sensitivity directivity becomes nearly beam-like, so that malfunctions caused by reflected waves generated by reflection from a photosensitive drum or roller, as in the conventional case, are less likely to occur.

In the above embodiment, the ultrasonic speaker 4 is arranged above,
The ultrasonic microphone 3 is disposed below to receive the sound waves (reflected sounds) from the ultrasonic speaker 4 via the ultrasonic reflection horn 11. The same effect can be obtained even if the sonic speaker 4 is disposed below and the ultrasonic microphone 3 is disposed above.

As explained above, according to the present invention, the ultrasonic speaker and the microphone can be directed in the same direction, and there is no need to attach a filter to the lower acoustic transducer as in the conventional case, which prevents contamination. Moreover, since it uses a reflective horn, there is no possibility of malfunction due to reflected sound, making it suitable for use in places where operating conditions are not favorable.

[Brief explanation of the drawing]

FIG. 1 shows the constituent countries of a conventional ultrasonic sensor, and FIG. 2 shows the constituent countries of an embodiment of the ultrasonic sensor according to the present invention. 1... Paper to be detected [object to be detected], 3...
...Ultrasonic microphone, 4...Ultrasonic speaker, 5...Ultrasonic wave, 6...Reception circuit.

Claims (1)

[Scope of utility model registration request] In a block-type ultrasonic sensor that detects a detected object by detecting that the sound waves emitted from an ultrasonic speaker are blocked by the detected object and do not reach the ultrasonic microphone, a sensor facing the ultrasonic speaker or ultrasonic microphone is used. an ultrasonic reflection horn is disposed in between, and an ultrasonic microphone that faces the ultrasonic reflection horn and receives the reflected sound from the ultrasonic speaker via the reflection horn; An ultrasonic sensor comprising: an ultrasonic speaker that emits ultrasonic waves to an ultrasonic microphone; and an object to be detected passes between the ultrasonic speaker and the ultrasonic microphone.