JPH0542380Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a paper detector.

For example, it can be used to detect whether paper is being fed in a printer.

[Prior Art] As shown in FIG. 5, a conventional paper detector includes a container body 5 that houses detection elements such as a light emitting element and a light receiving element inside, and a lead wire 6 connected to the container body 5. It is composed of a connected connector 7.

To incorporate this into a printer, for example,
As shown in FIG. 6, an amplifier circuit (not shown) for amplifying and digitizing the signal detected by the paper detector is formed on a printed circuit board 2 that can be inserted into and removed from the connector 1, and the connector 3 Install it. On the other hand, the paper detector body 5 is attached to the paper guide 9 attached to the outer peripheral surface of the platen 8 with a slight gap, and the connector 7
into the connector 3. Note that the connectors 3 and 7 are separate from the connector 1 in consideration of ease of replacement due to the lifespan of the paper detector.

Therefore, if the paper 10 is allowed to pass between the platen 8 and the paper guide 9, the paper detector can detect the presence or absence of the paper 10 from the difference in reflectance between the platen 8 and the paper 10. The detection signal is guided to the printed circuit board 2 via the lead wire 6 and the connectors 7, 3, digitized by the amplifier circuit, and then sent to other electrical circuits.

[Problems to be Solved by the Invention] The structure shown in FIG. 6 is inefficient because the connectors 3 and 7 must be inserted and removed every time the printed circuit board 2 is inserted and removed from the connector 1. Moreover, if the connector 3 is located away from the paper detector in order to improve the work efficiency when inserting and removing the connectors 3 and 7, the lead wire 6 will be long and the lead wire 6 will need to be long. The lead wires 6 become intertwined, resulting in poor workability, and it is necessary to secure the lead wires 6 at several locations with tweezers or the like.

The purpose of the present invention was to solve these problems.The purpose of the present invention was to improve the workability when inserting and removing printed circuit boards, and at the same time, to create a paper detector that prevents the detection signal from becoming unstable. Our goal is to provide the following.

[Means for solving the problem] Therefore, in the present invention, first, in order to improve the workability when inserting and removing printed circuit boards,
An electrically conductive leaf spring is provided which resiliently contacts the connection terminals of the printed circuit board when the printed circuit board is inserted into the connector. However, if left as is, the detection signal would become unstable due to the influence of contact resistance between the leaf spring and the connection terminal of the printed circuit board. The configuration includes a circuit that converts the detected signal into a digital signal.

Specifically, in a paper detector that has a detection element inside the container body, and a signal detected by the detection element is connected to a printed circuit board that can be freely inserted into and removed from a connector so as to conduct electricity, An end portion is fixed to the container, a tip portion is formed to be elastically deformable in the insertion/extraction direction, and when the printed circuit board is inserted into the connector, the tip portion is connected to the connecting terminal of the printed circuit board. Three electrically conductive leaf springs that come into elastic contact with the body are provided in the body, and a circuit is provided between the leaf springs and the detection element to convert the signal detected by the detection element into a digital signal. The present invention is characterized in that the base end portions of two leaf springs are connected to the power source for the circuit, and the base end portion of the remaining leaf spring is connected to the power source for the digital signal output of the circuit.

[Operation] To pull out the printed circuit board from the connector, simply pull out the printed circuit board. Further, when the printed circuit board is inserted into the connector, the leaf spring provided on the main body comes into elastic contact with the connection terminal as the printed circuit board is inserted. Therefore, there is no need to manually insert and remove the connector each time a printed circuit board is inserted or removed, as was the case in the past.
Furthermore, since lead wire processing is not required, work efficiency when inserting and removing printed circuit boards can be improved.

Additionally, since a circuit is installed between the leaf spring and the detection element to convert the signal detected by the detection element into a digital signal, detection is possible due to the influence of contact resistance between the leaf spring and the connection terminal of the printed circuit board. This can prevent signal instability.

[Embodiment] Hereinafter, an embodiment in which the present invention is applied to a printer will be described based on FIGS. 1 to 4.

FIG. 4 shows a schematic diagram of the printer. In the figure, a connector 1 connected to an electric circuit (not shown)
1, a printed circuit board 12 on which a printed circuit is formed is provided so as to be freely inserted and removed in the left and right directions in FIG. On the upper surface side of the printed circuit board 12, a conductive connection terminal 13 electrically connected to the printed circuit is provided so as to protrude from the printed circuit surface of the printed circuit board 2, and here protrude upward. The upper surface of the connection terminal 13 is an inclined surface 13 that gradually slopes upward as it goes from the front end in the insertion direction to the rear end in the insertion direction of the printed circuit board 12.
It is formed in A.

On the other hand, a paper guide 17 is provided on the outer periphery of the platen 14 located above the printed circuit board 12 with a gap 16 through which the paper 15 can pass.
A paper detector 18 for optically detecting the presence or absence of the paper 15 passing through the gap 16 between the platen 14 and the paper guide 17 is attached to the paper guide 17 with its lower end inclined toward the insertion direction of the printed circuit board 12. ing.

The paper detector 18 has a plurality of locking claws 23A, 2 that engage with the paper guide 17, as shown in FIG.
3B is provided. Vessel 2
1 includes three leaf springs 24 made of conductive material.
A, 24B, and 24C are attached in parallel and protruding from the container body 21. Leaf springs 24A, 24
When the printed circuit board 12 is not inserted into the connector 11, the lines B and 24C are linear as shown by the chain lines in FIG.
When the printed circuit board 12 is inserted into the terminal 1, the printed circuit board 12 is elastically deformed and comes into elastic contact with the connecting terminal 13 at a position where it slides on the inclined surface 13A of the connecting terminal 13 of the printed circuit board 12.

In addition, inside the vessel body 21, there are
As shown in the figure, a light emitting element D such as a light emitting diode
1 and a light receiving element TR1 such as a phototransistor
are provided, and these elements D1,
An amplifier circuit 22 is provided between TR1 and the leaf springs 24A, 24B, and 24C to convert the signal detected by the light receiving element TR1 into a digital signal. The amplifier circuit 21 includes four resistors R1, R2, R3, R
4 and one transistor TR2. These elements are the leaf springs 24A, 24
B, 24C, these leaf springs 24
A circuit is constructed using A, 24B, and 24C. Note that 24A is used as an output circuit, 24B is used as a grounding circuit, and 24C is used as a power supply circuit.

Next, the operation of this embodiment will be explained.

When the printed circuit board 12 is not inserted into the connector 11, the leaf springs 24A, 24B, and 24C of the paper detector 18 are linear as shown by the chain lines in FIG.

When the printed circuit board 12 is inserted into the connector 11, the plate springs 24A, 24B, and 24C are elastically deformed in the insertion direction of the printed circuit board 12 by the inclined surface 13A of the connection terminal 13. Eventually, when the printed circuit board 12 is fully inserted into the connector 11, the leaf spring 24 of the paper detector 18
A, 24B, and 24C contact the connection terminal 13 in an elastically deformed state.

In this state, the signal detected by the light receiving element TR1 is amplified by the amplifier circuit 22, converted into a digital signal, and then sent to the printed circuit board 12 through the leaf spring 24A.

Therefore, according to this embodiment, the connection terminal 13 of the printed circuit board 12 is connected to the body 21 of the paper detector 18.
conductive leaf springs 24A, 24B,
24C, when inserting and removing the printed circuit board 12, it is sufficient to simply insert and remove the printed circuit board 12. In other words, there is no need to manually connect and disconnect the connector between the printed circuit board and the paper detector each time the printed circuit board is inserted or removed, and there is no need to process the lead wires, so the printed circuit board The work efficiency when inserting and removing 12 can be improved compared to the conventional method.

Furthermore, since an amplifier circuit 22 for converting the signal detected by the light receiving element TR1 into a digital signal is provided inside the body 21, the connection terminal 13 of the printed circuit board 12 and the leaf springs 24A, 24B, 24C are connected. It is possible to prevent the detection signal from becoming unstable due to contact resistance in the part. Moreover,
This means that there is no need to provide an amplifier circuit on the printed circuit board 12 side.
2 can be reduced in size, which has the effect of reducing costs.

Further, since the upper surface of the connection terminal 13 is formed into an inclined surface 13A that gradually slopes upward from the front end to the rear end in the insertion direction of the printed circuit board 12, the leaf spring 2
4A, 24B, and 24C can be smoothly elastically deformed. Moreover, when the printed circuit board 12 is completely inserted into the connector 11,
Since the leaf springs 24A, 24B, and 24C contact the connection terminal 13 in an elastically deformed state, a constant contact pressure can always be obtained.

Further, this has the advantage that the vertical relationship between the contact terminal 13 and the paper detector 18 does not have to be strictly defined. Furthermore, since the inclined surface 13A has a constant length along the direction in which the printed circuit board 12 is inserted and removed, the positional relationship between the paper detector 18 and the connection terminal 13 in the direction in which the printed circuit board 12 is inserted and removed is not strictly defined. There are good advantages.

[Effects of the invention] As described above, according to the invention, since a conductive leaf spring is provided in the container body to make elastic contact with the connection terminal of the printed circuit board, it is not possible to insert or remove the printed circuit board as in the conventional case. Since it is not necessary to insert and remove the connector that connects the printed circuit board and the paper detector every time the printed circuit board is inserted and removed, the work efficiency when inserting and removing the printed circuit board can be improved.

In addition, a circuit is installed between the leaf spring and the detection element to convert the signal detected by the detection element into a digital signal, so detection can be made by the contact resistance between the leaf spring and the connection terminal of the printed circuit board. It is possible to prevent the signal from becoming unstable.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is a perspective view showing the inside of the paper detector, Figure 2 is a circuit diagram showing the amplifier circuit, and Figure 3 is a paper detector circuit diagram. FIG. 4 is a perspective view showing the appearance of the device, and FIG. 4 is a diagram showing the schematic configuration of the printer. FIG. 5 is a perspective view showing a conventional paper detector, and FIG. 6 is a diagram showing a state in which the conventional paper detector is installed. 11... Connector, 12... Printed circuit board, 13... Connection terminal, 18... Paper detector, 2
1... Instrument body, 22... Amplifier circuit, 24A, 24
B, 24C...plate spring, TR1...light receiving element (detection element).

Claims (1)

[Claim for Utility Model Registration] A paper detector that has a detection element inside the body and connects the signal detected by the detection element to a printed circuit board that can be freely inserted into and removed from the connector. In this case, a proximal end portion is fixed to the container body, a distal end portion is formed to be elastically deformable in the insertion/extraction direction, and when the printed circuit board is inserted into the connector, the distal end portion is formed into a printed circuit. Three electrically conductive leaf springs that come into elastic contact with the connection terminals of the board are provided on the body, and a signal detected by the detection element is converted into a digital signal between these leaf springs and the detection element. A sheet of paper characterized in that a circuit is provided, the base ends of two leaf springs are connected for power supply of the circuit, and the base end of the remaining leaf spring is connected for output of a digital signal of the circuit. Detector.