JPH0342389Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a conveyed sheet detection device that detects a sheet being conveyed in, for example, a copying machine, a printer, a printing machine, or the like.

[Conventional technology]

Generally, this type of device has a touch piece on the paper conveyance path, and when the paper moving along the path pushes the touch piece and passes, the movement of the touch piece is controlled by electrical switching, light, magnetism, or By recognizing changes in static electricity, etc., it is possible to detect whether the leading edge of the paper has reached the leading edge, whether the paper exists or not, and whether the trailing edge has passed during the conveyance process.

That is, as shown in FIG. 5, a photointerrupter B, for example, is disposed at the base end of the touch piece A, with the tip end of the touch piece A bearing the base end facing the conveying process. This tentacle A is always placed in front of the conveyance path of the paper C under its own weight, but normal movement cannot always be guaranteed due to the rattling of the tentacle support and interference caused by dust such as paper powder. The touch piece A pushed and moved by the passing paper C may not return to its original normal position. Therefore, there are drawbacks such as frequently causing errors in the detection of the paper C, which in turn leads to malfunctions of the apparatus.

[Problem that the invention attempts to solve]

In order to eliminate this drawback, a return spring is provided on the contact piece, and when the paper passes, the contact piece is pushed against this return spring, and after passing the paper, the restoring force of the return spring ensures that it returns to the normal state. All you have to do is put it back in place. However, reliably activating the contact piece and the return spring at the leading edge of the paper during transport tends to cause damage to the paper, such as wrinkles and folding of the leading edge. It is difficult to employ it, especially in the equipment that requires it.

In other words, if the return spring is weakened, the contact piece cannot be reliably returned to its normal position, whereas if it is made strong, contradictory conditions exist at the leading edge of the paper, making it difficult to always obtain reliable operation. Conventionally, the weight of the tentacles and the supporting direction of the tentacles have been modified, but if the weight of the tentacles is made too heavy, it will damage the leading edge of the paper, and if it is made too light, it will not return properly.

In addition, when the paper reciprocates on the conveyance path, the return spring of its own weight is subject to repeated compression and tension loads, and the return spring tends to weaken due to the creep phenomenon, resulting in significant defects in its durability. be.

[Means for solving problems]

In view of the above points, this invention allows the contact of the detection means facing the conveyance path to be actuated by a weak force from the leading edge of the paper, quickly returns to its normal position after the paper has passed, and its movement is reliable and reliable. It is smooth and durable, and can stably detect a wide range of paper types.
Moreover, the main purpose of the present invention is to provide a conveyed sheet detection device with excellent responsiveness.

In other words, the paper conveyance detection device of this invention has a contact whose tip end faces the paper conveyance path and whose base end is swingably supported on the machine frame as appropriate, and which detects vibration by the engagement of this contact with the paper. In a conveyance sheet detection device comprising a detection means for electrically, optically or magnetically recognizing movement, the contact is positioned in a normal position with its tip facing the conveyance path due to its own weight, and the contact is characterized in that it is provided with a biasing means that acts on the contact at a position where the contactor is swung from the normal position by a predetermined swing angle or more, and applies a biasing force to the contact in the direction of the normal position. It is.

As a result, the contact moves while engaging with the leading edge of the paper in a free state where no biasing force is applied, and with the leading edge resting on the paper, the biasing means acts, following the conveyed paper and making contact. The child is first pushed with a light force by the leading edge of the paper, and then is lifted up while resting on the paper. At this time, a biasing force is applied to bias the biasing means, and after the trailing edge of the sheet has passed, the force of the biasing means returns to the normal position. Therefore, the followability of the contact and, by extension, the responsiveness of the detection means are improved, and the contact swings reliably and smoothly following the paper. In addition, detection of a wide range of paper, including extremely thin paper, can be performed stably over a long period of time.

〔Example〕

Hereinafter, one embodiment of the paper conveyance detection device of this invention will be described in detail with reference to the drawings, taking as an example the case where it is adopted in an automatic document feeding device of a copying machine.

First, as shown in FIG. 1, reference numeral 1 denotes a document setting surface of a copying machine, and a normal copying optical system is incorporated inside the copying machine. A conveying means indicated by the general symbol 2 is attached on this document setting surface 1, and this conveying means 2
is composed of a conveyor belt, an endless belt, or a combination thereof, which feeds and discharges sheets of original documents along the document setting surface 1. An endless belt 7 is stretched between them, and the slack side of the endless belt 7 is in close contact with the original set surface 1 to transport the sheet of the copy original.

At one end of this conveyance means 2, there is a document supply table 8.
Further, at the other end, a document reversing path roller 9 and a paper ejection stacker 3 are provided in series. The supply table 8 includes a normal document stacker 8a and a separation means 8b.
It separates the sheets on the document stacker 8 one by one and sends them to the conveyance means 2. Further, the front/back reversing roller 9 rotates the document setting surface 1
After the sheet is wrapped around a pinch roller 10 and turned over, it faces the original set surface 1 again. Furthermore, the paper discharge stacker 3 is adapted to accommodate the paper whose path has been changed by the switching gate 4.

The conveying means 2, the separating means 8b, and the front-back reversing roller 9 are connected to a drive motor (not shown), and the sheets on the document stacker 8a are separated one by one and sent to the conveying means 2. The paper is fed and set at the copy reference position on setting surface 1. After copying is completed, the paper on the document set surface 1 is sent to the front-back reversing roller 9 by the conveying means 2, and after the front-back reversing roller 9 reverses the paper, the sheet is transferred to the conveying means 2 again.
The document is then fed and set at a reference position on the document setting surface 1.

In such an apparatus, it is necessary to detect the paper during the conveyance process. For example, use this as the document stacker 8.
This is done by the illustrated sensor _S1 which detects the leading edge or trailing edge of the sheet fed out from a, and stops the conveying means 2 after a predetermined time based on this as a reference to set the sheet at the copying reference position. Alternatively, the paper that has been copied on the original set surface 1 may be transferred to the conveying means 2.
This is done by the illustrated sensor _S2 which detects the paper when it is activated and discharged towards the paper discharge stacker 3 or front/back reversing roller 9. This sensor _S2 is a jam sensor that is used when the paper does not arrive after a predetermined period of time after the conveyance means 2 is started. In this way, it is necessary to provide paper detection means at several locations.

The sensor _S2 detects when the paper does not arrive even after a predetermined period of time has elapsed from the activation of the transport means 2 when the transport means 2 discharges the paper on the document setting surface 1 (transfers it to the left side in FIG. 1). The device stops working as the paper jams.

In conjunction with this, when the paper is reversed from front to back through the front-back reversing roller 9 and transported to the document setting surface 1 again, this sensor _S2 detects the leading or trailing edge of the paper, and the paper is set based on this. After the expected time to reach the copying reference position on surface 1, the conveyance means 2 is stopped.

The present invention can be applied to such a sensor _S2 as shown in Fig. 2 A and B.

A contactor 21 consisting of a hanging piece is swingably supported on the machine frame as appropriate, and its tip end 22 faces the conveyance path 31 of the paper 30. In the illustrated example, a resin member is supported on a frame 32 by a shaft 23.

The base end 24 of this contactor 21 is engaged with a detection means consisting of a photo interrupter 25, and this detection means is fixed to the frame 32.

The detection means used in this invention include optical contacts such as the photointerrupter 25 described above, electrical contacts such as a micro switch, magnetic and electrostatic contacts such as a reed switch, etc. Good too.

Looking at the contactor 21, the spring 26 serving as the biasing means does not apply any biasing force in the normal position shown in FIG. 2A. That is, as shown in FIG. 3, a spring is wound around the shaft 23 of the contact 21 so that a biasing force is applied when the contact 21 rotates (swings) clockwise or counterclockwise by a predetermined angle or more. 26 to the proximal end 24 of this contact 21.
It is extended to the side as shown.

Next, FIG. 4 shows a case where the paper 30 moves only in one direction along the conveyance path 31, and the contact
As in the previous figure, a spring 26 is stretched so that no biasing force is applied in the normal position, but a biasing force is exerted when rotated by a predetermined angle.

[Effect]

Next, the effect of this invention will be explained. When the paper 30 is conveyed to the conveyance path 31 in the normal position shown in FIG. oscillate. As the paper 30 advances further, the contactor 21 is moved to the state shown in FIG.
At this time, the biasing force of the spring 26 acts for the first time. If the contactor 21 is still swung against this, the base end 24 of the contactor 21 will come off the photointerrupter 25 of the detection means and will generate a detection signal.
When the rear end of the paper 30 comes off the contact 21, the contact 21 quickly returns to its normal position in FIG. 2 due to its own weight and the accumulated force of the spring 26.

The operation of the one shown in FIG. 4 is similar to that of the previous one.

[Effect of idea]

Since the paper conveyance detection device of this invention has the above-mentioned configuration, it has the following effects.

In other words, by the biasing means that operates at a predetermined angle or more,
The responsiveness when rocking by the leading edge of the paper is good, and the contactor 21 is less likely to malfunction due to vibration or the like.

Furthermore, in the normal position, the urging force of the urging means is not applied, so there is no damage such as folding of the leading edge of the paper, and furthermore, the contact 21 does not return to its original position completely due to the hysteresis of the spring that is the urging means. Never.

Moreover, since the biasing force of the biasing means is applied at a predetermined angle or more, the contactor 21 is reliably returned to its original position.
Since the responsiveness when the trailing edge of the paper passes is good and there is little sagging due to hysteresis of the spring, a highly durable conveyed paper detection device can be obtained.

[Brief explanation of drawings]

Figures 1 to 4 are for explaining an embodiment of this invention. Figure 1 is a schematic diagram for explaining the general configuration of a copy document feeding device, and Figure 2A is a diagram of the invention. An enlarged front view showing the conveyed paper detection device;
B is a side view thereof, FIG. 3 is a front view in an operating state, and FIG. 4 is a front view showing another embodiment. Also the fifth
The figure is a diagram for explaining the prior art. S ₁ , S ₂ ... sensor, 21 ... contact, 22 ...
... distal end, 23... shaft, 24... proximal end, 25...
...Photo interrupter, 26...Spring, 30
... Paper, 31 ... Conveyance path, 32 ... Frame.

Claims (1)

[Scope of utility model registration request] A contact whose tip end faces the paper conveyance path and whose base end is swingably supported on the machine frame as appropriate, and the swinging caused by the engagement of this contact with the paper is recognized electrically, optically, or magnetically. In the conveyance sheet detection device, the contactor is positioned at a normal position where its tip faces the conveyance path due to its own weight, and the contactor is rotated at a predetermined swing angle from the normal position. Acting on the contact at a position where it has swung above,
A conveyance sheet detection device characterized in that a biasing means is provided for applying a biasing force to the contactor in the direction of the normal position.