JPH0710308Y2 - Paper detection sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention, in a copying machine, a facsimile, a laser printer, etc., receives a contact with paper that is fed in or sent out, moves a magnet, and moves the magnet. The present invention relates to a paper detection sensor that uses a magnetoelectric conversion element that detects a change in the amount of magnetic flux due to the switching and uses switching, and that has antistatic measures.

<Prior Art> As shown in FIG. 7, a conventional paper detection sensor includes a lever 11 that comes into contact with the fed paper 10, a magnet 14 fixed to one end of the lever 11, and a magnet 14 of the magnet 14. And a magnetoelectric conversion element 13 for detecting a change in the amount of magnetic flux due to separation and contact.

The lever 11 is usually made of a plastic member having a substantially V-shaped side surface, and a rotary shaft 15 for rotatably supporting the lever 11 is attached to a substantially central portion thereof. Also, the rotation axis
A coil spring (not shown) is wound around 15, and normally,
The lever (11) is urged so that the magnet (14) fixed to the lower end is close to the magnetoelectric conversion element (13).

On the other hand, a magneto-electric conversion element 13 such as a transmissive photo interrupter or a reed switch is supported and fixed on a mounting substrate (not shown) by being locked to the rotating shaft 15.

Then, the paper 10 moves in the direction of arrow R in FIG.
When the tip end of 11 is contacted, the lever 11 rotates in the direction of arrow S about the rotation shaft 15 as a fulcrum against the elastic force of the coil spring.

As a result, the magnet 14 fixed to the lower end of the lever 11
Is separated from the magnetoelectric conversion element 13 and the magnetoelectric conversion element 13
The amount of magnetic flux with respect to changes. Due to this change in the amount of magnetic flux, the magnetoelectric conversion element 13 performs switching so as to be triggered by the subsequent operation of the device.

<Problems to be Solved by the Invention> However, since the lever of such a paper detection sensor is usually made of plastic, static electricity is easily generated due to friction with the paper or the like. In particular, in recent years, static electricity has become more and more likely to be generated as the paper passing speed of the copying machine and the like is increased.

Therefore, there is a problem in that, due to the generation of such static electricity, noise generated during the discharge adversely affects other components inside the device, electronic circuits, and the like. For example, there is a problem in that toner adheres to the tip of the lever due to static electricity, which causes improper fixing of the copy or transfer (linear stain).

Further, in order to prevent such static electricity trouble, for example, there is a device provided with a noise filter circuit or the like inside a device such as a copying machine, but in this case, the structure of the device becomes complicated and it is disadvantageous in terms of cost.

An object of the present invention is to solve the above problems and to provide a paper detection sensor that can prevent electrostatic charge generated by friction between a paper and a lever and that can be manufactured at a low cost with a simple structure. To do.

<Means for Solving the Problems> The present invention provides a mounting frame detachably attached to a substrate having a ground connection portion, a magnetoelectric conversion element fixed at a proper position of the frame, and a support shaft. A rotating lever that is rotatably attached to the frame and has one end as a force receiving end, and is fixed near the other end of the rotating lever. A magnet arranged so as to approach or separate from the magnetoelectric conversion element, and an intermediate portion thereof is wound around and fixed to the support shaft, and one end portion thereof is locked at an appropriate position of the frame and the earth connection portion. And a conductive winding spring member for returning the lever, which has a paper contact portion exposed at the force receiving end and which is locked at a proper position of the rotary lever. A paper detection sensor.

<Embodiment> Hereinafter, the antistatic paper detection sensor of the present invention will be described with reference to FIGS.
An explanation will be given based on one embodiment shown in the drawing.

Reference numeral 1 denotes a paper detection sensor according to this embodiment. Reference numeral 2 denotes a substrate fixed to a device such as a printer, to which a mounting frame 5 having a box body 3 containing a magnetoelectric conversion element 4 is detachably mounted. The substrate 2 is made of a conductive material such as metal and is connected to the earth circuit 2a.

The magnetoelectric conversion element 4 such as a reed switch is incorporated in the box body 3 as shown in FIG. As shown in FIG. 1, a lead wire 4a of the magnetoelectric conversion element 4 is drawn out of the box body 3 and connected to a switching circuit (not shown). A transmissive photointerrupter and its holder may be provided instead of the magnetoelectric conversion element 4 and the box 3 (not shown).

The frame 5 is made of a plastic material or the like, and as shown in FIGS. 1 and 2, the box body 3 is arranged at the rear portion, and has a pair of side plates 5a, 5b facing each other and a bottom plate 5e which are integral with each other. It is a molded body of structure. In addition, a protrusion 5f for positioning which fits with a central hole 2b formed in the substantially central portion of the substrate 2 is provided in a substantially central portion on the back surface of the bottom plate portion 5e, while the side plate portion 5e is provided.
Attachment tongues 5c and 5d are formed in a bifurcated shape on the outside of the lower portions of a and 5b.

Claws 5g, 5h are formed at the lower ends of the mounting tongues 5c, 5d, and as shown in FIGS. 5 and 6, a substantially rectangular shape is formed in the substrate 2 with a central hole 2b interposed therebetween. The holes 2c, 2d are snap-fitted by the elastic force of the attachment tongues 5c, 5d. As a result, the frame 5 is detachably attached to the substrate 2.

A support shaft 6 is mounted between the side plate portions 5a and 5b.

Reference numeral 7 is a turning lever made of a plastic material or the like.
As shown in the drawing, a bearing boss portion 7a is formed in a substantially central portion of the support shaft 6 so that the support shaft 6 is inserted therethrough, and the support boss portion 7a is configured to be rotatable forward and backward about the support shaft 6 as a fulcrum. Further, a magnet portion 9 including a magnet box body 9a and a magnet 9b built in the box body 9a is fixed to the lower end of the rotating lever 7, while the other end side above the bearing boss portion 7a. That is, on the side of the force receiving end that receives the external force of the movement of the paper, the holding portions 7b, 7c for locking the winding spring 8 are formed in an inward groove shape along the longitudinal direction thereof (see FIGS. 3 and 4). ).

Reference numeral 8 is a coil spring member for the paper detection sensor of the present invention. The coil spring member 8 is an integral structure made of an elastic wire material having electrical conductivity, which is bent to form a paper contact portion 8a, an intermediate coil portion 8b and a conducting portion 8c.

The conductive elastic wire preferably has excellent corrosion resistance.

The paper contact portion 8a is a portion that is projected and exposed from the force receiving end which is the upper end of the rotating lever 7, and may have any shape as long as it can contact the passing paper. To smooth the contact with the paper,
A curved portion that is bent along the paper traveling direction (for example, reverse U
It is preferable to form a curved portion). In such a case, the lower line end of the curved paper contact portion 8a is expanded by the elastic force, and the groove walls of the holding portions 7b and 7c are pressed to be held and held.

As shown in FIG. 2, the intermediate coil portion 8b is formed by winding a portion of the elastic wire member, which extends further downward from the pressed and held portion, around the support shaft 6 into a coil shape. Thus, the coil portion 8b urges the magnet portion 9 fixed to the lower end of the lever 7 and the magnetoelectric conversion element 4 fixed to the frame 5 in the approaching direction. The electric signal output from is held in the ON state.

The conducting portion 8c is a portion obtained by locking the winding end of the coil portion 8b through the side plate portion 5a so as to extend vertically along the attachment tongue piece 5c. Thus, the free end portion is shown in FIGS.
As shown in the figure, it is sandwiched between a mounting tongue piece 5c that snap-fits into the hole 2c of the board 2 and a hole wall forming the hole 2c, and is electrically connected to the board 2 to form an earth circuit. 2a
Is connected to.

<Operation> The paper detection sensor 1 of the present invention having the above-described structure is arranged at a predetermined position such as a facsimile machine or a copying machine and operates as follows.

First, normally, the elastic force of the intermediate coil portion 8b of the coil spring member 8 locked to the lever 7 causes the magnet portion 9 and the magnetoelectric conversion element 4 to approach each other, and the magnetic flux of the magnet 9b causes the magnetoelectric conversion element 4 to move. ON / OFF signal is output from.

On the other hand, when the paper 10 sent from the direction of arrow P in FIG. 4 tries to pass above the paper detection sensor 1, the paper 10 comes into contact with the paper contact portion 8a of the winding spring member 8 and the winding spring Member 8
Is rotated in the direction of arrow Q with the support shaft 6 inserted through the bearing boss portion 7a of the rotation lever 7 as a fulcrum.

As a result, the magnet portion 9 fixed to the lower end of the rotating lever 7 also rotates in the direction of the arrow Q, and the magnetoelectric conversion element 4
And the magnet 9b are separated from each other. As a result, the magnet 9b
The amount of magnetic flux with respect to the magnetoelectric conversion element 4 changes, and the electronic signal corresponding to this change is output from the magnetoelectric conversion element 4.

According to the paper detection sensor 1 of the present invention, the static electricity generated between the passing paper 10 and the winding spring 8 locked by the lever 7 is formed by the conductive elastic wire integrally with the winding spring member 8 Through the paper contact portion 8a, the intermediate coil portion 8b, and the conducting portion 8c, the electric current is conducted to the substrate 2 also made of a conductive material. Then, it is discharged through the earth circuit 2a provided on the substrate 2.

<Effect> According to the paper detection sensor of the present invention, the static electricity generated by the contact with the passing paper is discharged through the winding spring member made of the conductive member held by the lever and the earth circuit provided on the substrate. Therefore, it is possible to effectively prevent faults due to static electricity, such as improper fixing and transfer of a copy.
Therefore, it is possible to further increase the paper passing speed of a copying machine or the like.

In addition, since the paper detection sensor itself has anti-static measures,
It is not necessary to provide a device such as a noise filter circuit inside a device such as a copying machine as in the conventional case.

Further, the structure has a small number of parts and can be assembled very easily, which is advantageous in terms of cost.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the paper detection sensor of the present invention, FIG. 2 is a front view of the same embodiment, and FIG. 3 is a second view showing the arrangement relationship between a winding spring member and a rotating lever. Fig. III-III sectional view, Fig. 4 is Fig. 2 IV-IV sectional view, and Figs. 5 and 6 are views showing the relationship between the mounting substrate, the frame snap-fitted to the mounting substrate, and the coil spring member. Yes, fifth
FIG. 7 is a front view thereof, FIG. 6 is a bottom view thereof, and FIG. 7 is a side view showing a conventional paper detection sensor. 1 ... Paper detection sensor 2 ... Substrate 4 ... Magnetoelectric conversion element 5 ... Frame 6 ... Spindle 7 ... Rotating lever 8 ... Winding spring member 9 ... Magnet part

Claims (1)

[Scope of utility model registration request] 1. A mounting frame detachably attached to a substrate having a grounding connection, a magnetoelectric conversion element fixed at a proper position of the frame, and rotatable with respect to the frame via a support shaft. A rotary lever that is attached and uses one end as a force receiving end, and is fixed near the other end of the rotary lever, and approaches or separates from the magnetoelectric conversion element as the rotary lever rotates. And the middle part thereof is wound around and fixed to the support shaft, and one end of the magnet is locked at a proper position of the frame and is connected to the ground connection part, and the other end part is fixed. Is a paper detection sensor capable of preventing electrification, comprising: a conductive coil spring member for lever return, which has a paper contact portion exposed at a force receiving end while being locked at a proper position of the rotating lever.