JPS6148755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a card-like paper feeding device in a computer terminal device, a printing device, or the like.

This type of paper feeding device is generally provided with a mechanism that prevents two or more sheets of paper from being fed one on top of the other at a time. There are two types of this two-sheet feed prevention mechanism: a rotating gate type that uses a roller or a belt, and a fixed gate type.The rotating gate type uses a feed roller 10 (or a feed belt) and a The paper 12 is configured to pass between a separation roller 11 (or a separation belt) having a relatively slow circumferential speed,
The feeding of two or more sheets of paper is prevented by frictional forces generated in opposite directions between the paper 12 and each of the rollers 10 and 11, respectively. The rotary gate type includes a separate type in which the peripheral surfaces of the feed roller 10a and the separation roller 11a are flat, as shown in the cross-sectional view seen from the paper feeding direction in FIG. 2a.
As shown in the sectional view of FIG. 2b viewed from the paper feeding direction, protrusions are provided on the circumferential surfaces of the feed roller 10b and the separation roller 11b, and by interlocking the protrusions with each other, the coefficient of friction with the paper is improved. There is an overlap type. On the other hand, in the fixed gate type, as shown in FIG. 3, a slit is provided between blocking plates 13 and 14 through which only one sheet of paper 12 can pass, thereby preventing the feeding of two or more sheets of paper.

Now, when actually using a paper feeding device having this type of two-sheet feeding prevention mechanism, it is necessary to adjust the allowable paper passage thickness of the two-sheet feeding prevention mechanism according to the thickness of the paper used. That is, in the case of a mechanism as shown in Fig. 2a, the gap length _t1 is set according to the paper thickness, in the case of a mechanism as shown in Fig. 2b, the overlap length _t2 is set, and in the case of a mechanism as shown in Fig. 3, the gap length _t3 is set according to the paper thickness. It is necessary to set the

Conventionally, the permissible thickness for paper passage has been set by an operator who empirically determines the thickness of the paper and manually operates a switch. However, there is a problem in estimating the paper thickness based on the operator's judgment, which requires the operator to have a fairly high degree of specialized knowledge, as the number of types of paper has increased. Further, the conventional apparatus has a problem in that it is not easy to compensate for wear of rollers, belts, etc. when setting the allowable thickness for paper passage.

Therefore, the present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide a paper feeding device that can be easily operated even by a person without special knowledge regarding paper thickness. .

Another object of the present invention is to provide a paper feeding device that can easily compensate for wear of a mechanism that defines the allowable thickness of paper to pass through.

The features of the present invention that achieve the above-mentioned object include a gate mechanism that mechanically prevents the feeding of multiple stacked sheets of paper, a detection mechanism that detects the thickness of one sheet of paper, and a detection mechanism that detects the thickness of one sheet of paper. The present invention further includes a mechanism for controlling the allowable thickness of the paper passing through the gate mechanism according to the thickness of the paper.

The present invention will be explained in detail below with reference to Examples.

FIG. 4 is a diagram showing the configuration of an embodiment of the present invention. In the figure, 20 indicates the above-mentioned feed roller (or feed belt), and 21 indicates a separation roller (or separation belt). feed roller 20
is rotatably attached to its shaft 22, and the shaft 22 is fixed to a member 23 movable in the direction of the arrow. The member 23 has a rack 24
is attached to the rack 24, and the shaft 2
A pinion 25, which is rotationally driven by a motor 27 via a pinion 6, is engaged with the pinion 25. Therefore, the member 23, the shaft 22, and the feed roller 20 move in the direction of the arrow in response to the forward and reverse rotation of the motor 27 whose position is fixed.

Motor 27 is driven by a drive current sent from control circuit 29 via line 28. A potentiometer 31 is pivotally connected to a shaft 30 that rotates in synchronization with the rotation of the rotating shaft 26 of the motor 27, and the output voltage of the potentiometer 31 is connected to a line 32.
The signal is applied to the control circuit 29 via.

The paper thickness measuring mechanism 33 is a potentiometer 33a.
It is equipped with a movable member 33b and a fixed member 33c that are mechanically integrated with the rotating shaft of the paper, and by inserting a sheet of paper between the movable member 33b and the fixed member 33c, the thickness of the paper can be adjusted. The configuration is such that the value of the output voltage of the potentiometer 33a is determined accordingly. The output voltage of potentiometer 33a is applied to control circuit 29 via line 34 and adjustment resistor 35.

FIG. 5 is a block diagram of the control circuit 29 described above. In the figure, 40 is the output voltage of the potentiometer 33a applied through the line 34, i.e.
This is an amplifier circuit that amplifies a signal representing the thickness of one sheet of paper, and the output of this amplifier circuit 40 is applied to an arithmetic circuit 41 to determine the position of the feed roller 20 corresponding to the optimum overlap length t' ₂ for the paper thickness. An optimal position signal representing the position is calculated. This optimum position signal is applied to one input terminal of the comparison circuit 42. On the other hand, a voltage representing the rotational position of the motor 27 and therefore the actual position of the feed roller 20 is obtained from the potentiometer 31, which is compared via the line 32 and the amplifier circuit 43 as the actual position signal of the feed roller 20. is applied to the other input terminal of circuit 42. In the comparison circuit 42, the optimum position signal applied to both input terminals and the actual position signal are compared, and a signal having a value corresponding to the difference is sent to the drive circuit 44. The drive circuit 44 supplies a drive current to the motor 27 via a line 28 in accordance with the applied signal.
is applied to drive this. In this way, the feed roller 20 is controlled to the optimum position where the overlap length _t'2 is optimum.

Next, the method of operating the device of this embodiment and the associated operations will be explained. Before paper feeding, the operator takes out only one sheet of paper to be used for feeding and inserts it between the movable member 33b and the fixed member 33c of the paper thickness measuring mechanism 33 so that it comes into close contact with the surfaces of both members. As a result, a signal corresponding to the paper thickness is applied from the potentiometer 33a to the control circuit 29, and by the operation of the control circuit 29 as described above, the overlap length t' ₂ between the feed roller 20 and the separation roller 21 is set to the optimum value. automatically controlled.

Note that the paper thickness measuring mechanism 33 may be provided in a path through which the paper passes during the paper feeding operation, or
It may be provided at a position different from this passage. If it is installed in a passage, the overlap length or gap length, that is, the allowable thickness of the paper to be passed, is adjusted by feeding only one sheet of paper before the feeding operation. Further, in this case, it is desirable that the paper thickness measuring mechanism 33 be provided upstream of the two-sheet feeding prevention mechanism.

Next, a description will be given of an operation for compensating for the wear of the mechanism that defines the permissible thickness of paper to pass through, for example, the feed roller 20 and the separation roller 21. First, the members 33b and 33c of the paper thickness measuring mechanism 33 are brought into close contact with each other without inserting anything between them. In this state, if the adjustment resistor 35 is adjusted so that the gap length between the feed roller 20 and the separation roller 21 is constant, compensation for wear can be achieved. In order to know that the gap length is a constant value, for example, a gap gauge having a predetermined thickness may be used.

FIG. 6 shows another embodiment of the paper thickness measuring mechanism, in which 45 is a light emitting element such as an incandescent light bulb or a light emitting diode, 46 is an optical system, 47 is a sheet,
48 is a photodiode, a phototransistor,
A photoelectric conversion element such as a photocell, 49 is a current-voltage conversion circuit that converts the photocurrent from the photoelectric conversion element into voltage. That is, a photocurrent is obtained by inserting a sheet of paper between the light emitting element 45, which always has a constant luminous intensity, and the photoelectric conversion element 49, and this photocurrent is converted into the photocurrent and paper as shown in FIG. By applying the current to the current-voltage conversion circuit 49 having characteristics equivalent to a specific relationship with the paper thickness, it is possible to easily obtain an output voltage corresponding to the paper thickness.

As described above in detail, the paper feeding device of the present invention includes a detection mechanism that detects the thickness of one sheet of paper, and a gate mechanism that prevents paper from passing through the paper according to the thickness of the paper detected by the detection mechanism. Since the machine is equipped with a mechanism to control the allowable thickness, the allowable thickness of paper passing through the gate mechanism can be automatically set, and even those without specialized knowledge regarding paper thickness can operate it very easily and correctly. Furthermore, there is an advantage that compensation for wear of the mechanism that defines the permissible thickness for paper passage can be performed much more easily than in the prior art.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a paper feeding device, FIG. 2a, FIG. 2b, and FIG. 3 are sectional views showing various examples of a two-sheet feeding prevention mechanism. FIG. 4 is a configuration diagram of one embodiment of the present invention. 5 is a block diagram of the control circuit shown in FIG. 4, FIG. 6 is a block diagram of another embodiment of the paper thickness measuring mechanism shown in FIG. 4, and FIG. 7 is a characteristic showing the relationship between photocurrent and paper thickness. It is a diagram. 10, 10a, 10b, 20... feed roller,
11, 11a, 11b, 21...separation roller, 1
2, 47... Paper, 13, 14... Blocking plate, 2
2, 26, 30... shaft, 23... member, 24...
Rack, 25...Pinion, 27...Motor, 2
9... Control circuit, 31, 33a... Potentiometer, 33... Paper thickness measuring mechanism, 33b... Movable member, 33c... Fixed member, 35... Adjustment resistor,
40, 43...Amplification circuit, 41...Arithmetic circuit, 4
2... Comparison circuit, 44... Drive circuit, 45... Light emitting element, 48... Photoelectric conversion element, 49... Current voltage conversion circuit.

Claims (1)

[Scope of Claims] 1. A gate mechanism that mechanically prevents the feeding of multiple sheets of paper, a detection mechanism that detects the thickness of one sheet of paper, and a gate mechanism that mechanically prevents the feeding of multiple sheets of paper, a detection mechanism that detects the thickness of one sheet of paper, and a gate mechanism that mechanically prevents the feeding of multiple sheets of paper. A paper feeding device comprising: a mechanism for controlling the allowable thickness of paper passing through a gate mechanism. 2. The detection mechanism directly determines the paper thickness based on the output of the potentiometer when the paper is inserted between a movable member and a fixed member that are mechanically integrated with the rotary shaft of the potentiometer. A paper feeding device according to claim 1, comprising a measuring mechanism. 3. The paper feeding device according to claim 1, wherein the detection mechanism includes a mechanism that indirectly detects the thickness of the paper by measuring the light transmittance of the paper.