JPH01308322A - Paper residue detecting device for paper feed tray device - Google Patents

Abstract

PURPOSE:To detect steplessly in high accuracy a residual quantity of paper on a paper feed tray by providing a light detector which detects the residual quantity of paper on the paper feed tray being based on a quantity of light received from a light emitting source. CONSTITUTION:Paper on a paper feed tray 1 is fed sheet by sheet successively from the topmost paper by a paper feed roller 7, and it sends out the paper to be successively fed into the inside of a machine unit 9 by paper feed rollers 8. Since the paper feed tray 1 gradually rises following the above feed, a distance between a light emitting source 10 and a light detector 13 gradually increases, and a quantity of light received by the light detector 13 gradually decreases. This received quantity of light decreases in inverse proportion to a square of the distance between the light emitting source 10 and the light detector 13 when assumed the light emitting source 10 for a point source of light. Accordingly, a decreased or residual quantity of paper, loaded on the paper feed tray 1, can be known in a value in proportion to a square of the paper quantity by an output of an amplifier 14.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a paper remaining amount detection device for a paper feed tray device provided as an automatic paper feed mechanism for electrostatic transfer copying machines, laser printers, etc. be.

[Conventional technology]

In a conventional paper feed tray device for a copying machine or the like, for example, as shown in FIG.
2 is placed on the paper feed tray 21, and the paper feed tray 21 is raised according to the amount of paper on the paper feed tray 21 that decreases. on the other hand,
At the upper position of the paper feed tray 21 on which the paper group 22 is placed, the upper limit position of the paper group 22 on the paper feed tray 21 is regulated and the uppermost paper of the paper group 22 is fed into the machine one by one. A paper feeding roller 23 that can feed the paper is arranged.

As a result, the paper feed roller 23 rotates in the direction B, and the uppermost paper of the paper group 22 is transferred to the paper feed tray 22.
Even if the sheets are fed out sequentially from the top, the paper feed tray 21 will rise in the A direction by the thickness of the amount of sheets fed out, and the paper group 22
The uppermost sheet of paper is always in pressure contact with the paper feed roller 23. The paper sent out from above the paper feed tray 21 is fed between a pair of paper feed rollers 24, 24, and is further transferred to the machine body 25 by the paper feed rollers 24, 24.
The paper is automatically fed into the machine through the paper feed slot.

On the other hand, the body 25 includes a large number of detection switches 26 along the movement locus of the paper feed tray 21 which can be moved up and down.
・are arranged at predetermined intervals. A protrusion 2 is provided on the wall of the paper feed tray 21 facing the body 25.
1a is provided in a protruding manner, and each of the detection switches 26 is provided with an actuator 26a that can come into contact with the protrusion 21a.

As a result, when the uppermost paper of the paper group 22 on the paper feed tray 21 is fed into the machine body 25 one by one as the paper feed roller 23 rotates, the paper feed roller 23 rotates.
1 gradually rises in the A direction with the paper group 22 placed thereon, but in the rising process, the protrusion 21a of the paper feed tray 21 contacts the actuator 26a of the detection switch 26... The detection switch 26...
・Turn ON10FF. This detection switch 26...
By detecting the 0N10FF signal from the paper feed tray 21, the height position of the paper feed tray 21 is detected, and thereby the remaining amount of paper in the paper group 22 placed on the paper feed tray 21 is detected. .

[Problem that the invention seeks to solve]

However, according to the conventional device described above, in order to improve the accuracy of detecting the amount of paper remaining on the paper feed tray 21, it is necessary to
It becomes necessary to arrange as many detection switches 26 as possible within a limited space of 5. As a result, not only does this lead to a rise in manufacturing costs, but it is also necessary to increase the size of the device due to the need to secure a large space. There is also the problem that there are limits to what can be done.

[Means for solving problems]

In order to solve the above-mentioned problems, the paper remaining amount detection device for the paper feed tray device according to the present invention is movable in the vertical direction and moves up in accordance with the decrease in the amount of paper on the paper feed tray. a paper upper limit position regulating means disposed above the paper feed tray for regulating the upper limit position of a group of paper sheets placed on the paper feed tray;
In a paper feed tray device provided with a paper feeding means capable of feeding out the uppermost paper of a group of papers one by one, the paper feed tray is provided with a light emitting source, and
The present invention is characterized in that at least one of the lower and upper positions of the light emitting source is provided with a photodetector that detects the remaining amount of paper on the paper feed tray based on the amount of light received from the light emitting source.

[For production]

According to the above configuration, the top paper of the paper group on the paper feed tray is fed out one by one, and the paper feed tray gradually rises accordingly. Since light is emitted from the light emitting source installed in the paper feed tray and the amount of light received by the photodetector changes, the height of the paper feed tray can be adjusted based on the change in the amount of light detected by the photodetector. By detecting the position, it is possible to detect the remaining amount of paper on the paper feed tray.

If the above-mentioned photodetector is installed below the light emitting source installed in the paper feed tray, it will follow the paper being fed out one by one on the paper feed tray. Since the paper feed tray gradually rises, the amount of light received by the photodetector gradually decreases as the paper feed tray rises. The amount of light received by this photodetector is inversely proportional to the square of the distance between the light source and the photodetector, assuming that the light source is a point. therefore,
It is inversely proportional to the ascending distance of the paper feed tray, that is, the square of the amount of decrease in the thickness of the paper group placed on the paper feed tray.

As a result, a slight decrease in the amount of paper on the paper feed tray will appear as a large change in the output of the photodetector, and based on this change in the amount of irradiation and reception, the amount of paper remaining on the paper feed tray will be nullified. This makes it possible to detect stages with high accuracy.

〔Example〕

An embodiment of the present invention will be described below based on FIGS. 1 and 2.

As shown in FIG. 1, a paper feed tray 1 is removably set in a paper feed port of a machine body 9 such as a copying machine, and is driven by a motor 2 that can rotate in forward and reverse directions. A gear group 3 that decelerates the power of A drive mechanism 6 consisting of a wire 5, etc., which is connected to the side part 1a of the paper feed tray 1 from the boot IJ 4 via the other pulley 4, moves in the A direction from the upper limit position P to the lower limit position Q. Alternatively, it is configured to be able to move up and down in a horizontally stable manner up and down in the B direction.

On this paper feed tray 1, a paper group (not shown) consisting of a large number of stacked papers for copying is placed. 1 is set to increase.

At the upper position of the paper feed tray, there is a paper upper limit position regulating means (not shown) for regulating the upper limit position of a group of paper sheets placed on the paper feed tray 1, and a means for controlling the uppermost paper sheet of the paper group, one by one. A paper feeding roller 7 is provided as a paper feeding means that can feed the paper, and this paper feeding roller 7 is arranged so as to be able to rotate in the direction of arrow C.

When the uppermost paper of the paper group on the paper feed tray 1 comes into contact with the paper feed roller 7 with a predetermined pressure, the paper upper limit position regulating means detects the position of the uppermost paper and is shown in the figure. If the limit switch etc. does not operate and motor 2
On the other hand, when the pressing force of the uppermost sheet of paper against the paper feed roller 7 decreases or disappears due to paper feeding, the upper limit position regulating means causes the uppermost sheet of paper to exert the above-mentioned predetermined pressure against the paper feed roller 7. Start motor 2 until it reaches position A, and move paper tray l to
It is configured to rise in the direction. therefore,
The upper surface of the paper group placed on the paper feed tray 1 always comes into contact with the paper feed roller ruff with a constant pressing force, and the uppermost sheet of the paper group is sequentially transferred one by one by the paper feed roller ruff. When the paper is fed out, the paper feed tray 1 rises according to the amount of paper on the paper feed tray 1 that decreases.
The top sheet of paper is always kept at a constant height.

Note that as a paper upper limit position regulating means for regulating the upper limit position of the paper group placed on the paper feed tray l, for example, a paper feed roller 7 is used, and the pressing force applied to this paper feed roller rough is detected. The motor 2 may be configured to be started and stopped by using the paper upper limit position regulating means, and it goes without saying that such a paper upper limit position regulating means is also included in the gist of the present invention.

On the other hand, there is a lamp or LE on the bottom surface of the paper feed tray 1.
A light emitting source 10 such as D is provided. This light emitting source 10 is arranged inside an opaque case 11, and this case 1
1 through a small hole 12 formed downward in the light emitting source 10
The structure is such that the light from above is directed directly below.

Directly below the light emitting source 10 at a position below the movable range of the paper feed tray 1 and at a position that does not interfere with the vertical movement of the paper feed tray 1, there is a light detection device consisting of a light receiving element such as a blue cell. A device 13 is installed in a fixed state on the body 9. The photodetector 13 is capable of detecting the remaining amount of paper on the paper feed tray 1 based on the amount of light received from the light emitting source 10. That is, when light is emitted from the light emitting source 10, the photodetector 13 detects the amount of light received and generates an electrical output signal according to the amount of received light. The electrical output signal generated from the photodetector 13 is further amplified, for example, by an amplifier 14, thereby detecting the height position of the paper feed tray 1 and increasing the amount of paper remaining on the paper feed tray 1. This allows for accurate detection.

As a method of detecting the amount of paper remaining on the paper feed tray 1 based on the amount of light received by the photodetector 13, for example, as shown in FIG. The output from the amplifier 14 of the photodetector 13 in the state (voltage ■).

) and the output (voltage vr) from the amplifier 14 of the photodetector 13 when the paper feed tray 1 is fully loaded with paper are input to the arithmetic processing section, and the upper limit position P of the paper feed tray 1 is determined. A number of equally divided points are taken between and the lower limit position Q to calculate the voltage ■. The voltage from 1 to 2 is divided linearly, and the voltage value is stored according to the amount of paper on the paper feed tray 1. This makes it possible to steplessly detect the remaining amount of paper on the paper feed tray 1 through arithmetic processing using the interpolation method.

In this case, standards are set for the amount of light emitted from the light source 10, the input/output characteristics of the photodetector 13, and the human output characteristics of the amplifier 14,
It is necessary to adjust these characteristic values and the like to meet the above criteria in accordance with each device such as a copying machine. If the input/output characteristics of the current or voltage corresponding to the amount of light received by the photodetector 13 and the input/output characteristics of the photodetector 13 or the amplifier 14 have linear regularity, the above calculation process is performed. It will be very simple.

In the above embodiment, the photodetector 13 is installed below the paper feed tray 1, but the photodetector 13 is installed above the paper feed tray 1.
3 may be installed (in this case as well, the remaining amount of paper on the paper feed tray l can be detected steplessly in the same way as above).

In this case, it is necessary to install the light emitting source 10 on the upper surface of the paper feed tray 1 excluding the paper stacking section.

On the other hand, a through hole 1a for passing the light emitted from the light emitting source 10 is formed in a portion adjacent to the light emitting source 10 in the paper feed tray l, and a through hole 1a for passing the light emitted from the light emitting source 10 is formed at a position above the light emitting source 10 in the paper feed tray Another photodetector 15 is installed outside the movable range of the photodetector 1.

As a result, when the amount of paper loaded on the paper feed tray 1 gradually decreases and there is no more paper on the paper feed tray 1,
The through hole 1a of the paper feed tray 1, which was previously blocked by the paper placed on the paper feed tray 1, is now opened.
Since the light emitted from the light source 10 reaches the photodetector 15,
This photodetector 15 can detect the "no paper" state on the paper feed tray 1 over the entire movable area of the paper feed tray 1. When the photodetector 15 detects the "out of paper" state on the paper feed tray 1, the motor 2 is reversed,
The paper feed tray 1 is configured to be lowered to a position where it reaches the lower limit position Q and then stopped.

By providing the light emitting source 10 in the paper feed tray 1 in this way, it becomes possible to detect the remaining amount of paper on the paper feed tray 1 in a stepless manner, including the "out of paper" state. and,
At least one of the lower position and the upper position of the light emitting source 10,
That is, there are cases where the photodetectors 13 and 15 are provided at both the lower position and the upper position as in this embodiment, and cases where the photodetector 13 is provided only at either the lower position or the upper position.
It is within the scope of the invention.

Note that if paper feed tray 1 rises while there is no paper on paper feed tray 1, paper cannot be replenished until paper feed tray 1 descends again to the specified position, so paper feed tray 1 is at the lower limit position. The paper feed tray 1 is configured not to be raised when the photodetector 15 detects a "no paper" state when the paper feed tray 1 is located at the position Q.

In the above configuration, the sheets on the paper feed tray 1 are fed one by one by the paper feed roller 7 starting from the top one, and the paper fed from the paper feed roller 7 is fed out by the paper feed rollers 8, 8. They are sent into the interior of the fuselage 9 one after another. Along with this, the paper feed tray 1 gradually rises, so the distance between the light emitting source 10 and the photodetector 13 gradually increases, and the amount of light received by the photodetector 13 gradually decreases. If the light emitting source 10 is regarded as a point light source, the amount of received light decreases in inverse proportion to the square of the distance between the light emitting source 10 and the photodetector 13. Therefore, by the output of amplifier 14,
The amount of decrease in the amount of paper placed on the paper feed tray 1 or the remaining amount of paper can be determined by a value proportional to the square of the amount of paper remaining.

〔Effect of the invention〕

As described above, the paper remaining amount detection device of the paper feed tray device according to the present invention is movable in the vertical direction, and the upper position of the paper feed tray rises in accordance with the amount of paper decrease on the paper feed tray. A paper upper limit position regulating means for regulating the upper limit position of the paper group placed on the paper feed tray, and a paper feeding means for feeding out the uppermost paper of the paper group one by one are provided. In the paper feed tray device, the paper feed tray is provided with a light emitting source, and at least one of a lower position and an upper position of the light emitting source is provided with the remaining paper on the paper feed tray based on the amount of light received from the light emitting source. The structure is equipped with a photodetector that detects the amount.

This makes it possible to detect the amount of paper remaining on the paper feed tray with infinitely high precision, and also to detect the amount of paper remaining with a small number of photodetectors, reducing manufacturing costs. Since there is no need to secure a large space, the device can be made smaller. In particular, since a light source is provided on the paper feed tray, by installing photodetectors above and below this light source, it is possible to eliminate paper on the paper feed tray using only one light source.
This has the effect of being able to detect the remaining amount of paper, including the amount of paper, with high accuracy.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a schematic explanatory diagram of a remaining paper amount detection device, and FIG. 2 shows the amount of light received by a photodetector and the photodetector. FIG. 3 is a schematic explanatory diagram of a conventional paper remaining amount detection device. 1 is a paper feed tray, 1a is a through hole, 6 is a drive mechanism, 7 is a paper feeding roller (paper feeding means), 10 is a light emitting source, 13 and 15 are photodetectors, 14 is an amplifier, and P-Q are paper feeders. These are the upper and lower limit positions of the tray. 2nd g. !

Claims (1)

[Claims] 1. A group of sheets of paper placed on the paper feed tray at a position above the paper feed tray that is movable in the vertical direction and rises according to the amount of paper on the paper feed tray. In a paper feed tray device provided with a paper upper limit position regulating means for regulating the upper limit position of a paper group, and a paper feeding means capable of feeding out the uppermost paper of a group of papers one by one, a light emitting device is provided on the paper feed tray. A photodetector is provided at least one of a lower position and an upper position of the light emitting source to detect the remaining amount of paper on the paper feed tray based on the amount of light received from the light emitting source. A paper remaining amount detection device for a paper feed tray device, characterized by: