JPH09328242A - Paper sheet near end detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate supplement of paper sheets without imposing burden in paper feeding by arranging an optical path, which is emitted from a light emitting member, reflected by a reflecting member, and reaches a light receiving member, in such a state as blocked off, when there are sufficient paper sheets in a paper sheet storage part, and opened, when there are left a little. SOLUTION: A detecting member 4 is arranged in the top of stacked paper sheets 2 and a reflecting member 5 is arranged in the inner bottom of the rear part of a cassette 1. Light emitted from a light emitting part incorporated in the detecting member 4 returns thereto by reflected on the surface of the reflecting member 5 opposed to the detecting member 4. When a light receiving part detects the returned light, the detecting member 4 outputs a signal. It is so arranged that, when sufficient paper sheets 2 are mounted thereon the light from the light emitting part is incident at a prescribed angle θto a vertical line 6 of a paper sheet face and the extension light of the optical path is reflected in such a state as diagonally crossing the rear end edge part of the paper sheet 2, and when the paper sheets are left a little, the light reaches the reflecting member so as to reflect thereon. This constitution can facilitate supplement of the paper sheets without imposing burden in feeding of the paper sheets 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
The present invention relates to a sheet detection device of a sheet storage unit that feeds sheets one by one to an image forming apparatus such as a facsimile.

[0002]

2. Description of the Related Art Conventionally, when it is detected that a sheet has run out in a sheet storage section of an image forming apparatus, a detection signal is displayed on a display section. However, in the conventional paper storage unit, it is not possible to know from the outside how much paper remains inside, so if the paper runs out during continuous image formation, the operation is interrupted and the paper is replenished. However, it is very troublesome for the user, and there is a problem that the work efficiency is reduced.

A method of detecting the remaining amount of paper in the paper storage unit and informing the user of the detection is disclosed in Japanese Patent Application Laid-Open No. 01-197232.
It has been proposed in the publication. The swing lever is brought into contact with the upper surface of the stacked paper, and the swing lever is supported at a substantially midpoint by a fulcrum so as to be swingable, and the swing lever is exposed to the outside according to the amount of loaded paper. The other end swings up and down to notify the user of the remaining amount of paper inside. In this way, the remaining amount of the sheet can be known, and if the remaining sheet becomes very small, the sheet is replenished so that the sheet is not exhausted during the continuous image formation.

However, in this method, the swing lever comes into contact with the upper surface of the sheet, which causes a load for feeding the sheet. Further, since the swing lever projects to the sheet stacking portion, there is a problem that the swing lever is obstructed at the time of sheet supply. . In addition, the number of components increases, which causes an increase in cost.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a paper end detecting device for a paper collecting section which does not impose a load on paper feeding and can easily supply paper. Aim.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a paper storage unit for storing paper for feeding paper one sheet at a time to an image forming apparatus. The reflection member is arranged so that light from the light-emitting member is reflected by the reflection member and reaches the light-receiving member when a sufficient amount of paper is stored in the paper storage unit and the optical path is opened when the amount of paper is low. It is characterized by doing.

Further, the light emitting member is characterized in that light is obliquely incident on the surface of the paper when there is sufficient paper stored in the paper storage unit.

Further, it is desirable that the light emitting member and the light receiving member are arranged on the image forming apparatus main body side, and the reflecting member is arranged on the sheet storing portion.

It is desirable that the light emitting member, the light receiving member, and the reflecting member are arranged on the rear end side of the sheet storage portion.

It is preferable that the light-emitting member and the light-receiving member are arranged so as to face downward, and the light from the light-emitting member is cut obliquely at the rear end of the sheet.

The light-emitting member and the light-receiving member may be arranged to face downward, and the light from the light-emitting member may be cut obliquely at the side edge of the sheet.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cassette 1 as a sheet storage unit. Sheets 2 are stacked inside the cassette. A paper feed roller 3 is arranged at the front of the cassette, which is the side from which the sheets of the cassette are fed. The bottom plate 8 is located at the bottom of the cassette 1 and is urged upward by urging means (not shown) to press the loaded paper 2 against the paper feed roller 3. A detection member 4 is disposed above the stacked sheets 2. A reflecting member 5 for reflecting light is disposed on the inner bottom of the cassette at the rear of the cassette.

FIG. 2 shows the detecting member 4. The light emitting unit 9 and the light receiving unit 10 are built in, and the light emitted from the light emitting unit 9 is reflected by the surface of the reflecting member 5 facing the detecting member 4 so that the detecting member 4
Come back to. Reference numeral 7 denotes the paths of emitted light and reflected light, that is, the optical path. The light receiving unit 10 detects the light reflected and returned to the detection member 4. When the light receiving unit 10 detects light,
The detection member 4 outputs a detection signal.

As shown in FIG. 1, when the sheet 2 is sufficiently loaded, light from the light emitting section enters the sheet surface at a predetermined angle θ with respect to the vertical line 6 of the sheet surface, as shown in FIG. So that the extension of the optical path cuts the rear edge of the paper 2 diagonally,
When the paper 2 is slightly remaining, the light reaches the reflecting member 5 and is reflected, and the reflected light is arranged to be detected by the detecting member 4. By arranging the detection member 4 at the front edge of the sheet, the top surface of the sheet is always kept at a constant height by the bottom plate and the feed roller at the front of the sheet. It is not preferable because it cannot be opened.

The detecting member 4 is arranged so that the surfaces of the light emitting portion 9 and the light receiving portion 10 face downward and the reflecting surface of the reflecting member 5 faces upward. With this arrangement, the surface of the light emitting unit 9 and the light receiving unit 10 of the detection member 4 is hardly contaminated with dust or the like, so that the detection member 4 is not touched for cleaning, and the mounting accuracy of the detection member 4 is degraded. There is no fear.
Although the reflecting surface of the reflecting member 5 faces upward and is easily contaminated, the reflecting member 5 has a planar shape as compared with the detecting member 4 and is fixed to the cassette. There is no fear.

The near-end detection of a sheet will be described. FIG. 3 shows a case where sheets are sufficiently stacked in the cassette 1. The paper 2 blocks light emitted from the light emitting unit 9,
The light is reflected on the paper surface, cannot reach the light receiving unit 10, and the detection member 4 does not output a detection signal. FIG. 4 shows a case where the number of stacked sheets is reduced and the number of remaining sheets is reduced. Since the paper 2 does not block the light, the light reaches the reflecting member 5 and is reflected and returns to the light receiving unit 10 of the detecting member 4. Light receiving part 1
0 detects reflected light, and the detection member 4 outputs a detection signal. The image forming apparatus receives the detection signal and displays the near end on the display device to notify the user that the remaining paper is very small.

Similar effects can be obtained by arranging the detecting member 4 so that light is obliquely cut at the side edges of the sheet as shown in FIG.

[0018]

As described above, the detection member and the reflection member are arranged so as to block the light from the detection member when there is enough paper and to pass the light when the paper is low. And a paper near-end detecting device that can easily supply paper. Also, since the number of parts is small, the cost can be reduced.

Further, since the detecting member is arranged downward, the surface is hardly stained and there is no need to wipe the detecting member.
The mounting position is not disturbed by touching the detecting member. In addition, since the reflecting member is fixed on the cassette, even if the surface is soiled, even if the surface is wiped, the mounting accuracy is not deteriorated and the maintainability is improved.

Further, by arranging the detecting member so that light cuts the rear edge or the side edge of the sheet obliquely, the near end of the sheet can be reliably detected.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a sheet storage unit of the present invention.

FIG. 2 is a diagram illustrating a detection member, a reflection member, and an optical path.

FIG. 3 is a diagram illustrating an optical path when there is sufficient paper in a cassette.

FIG. 4 is a diagram illustrating an optical path when paper is low in a cassette.

FIG. 5 is a diagram illustrating a sheet storage unit in which a detection member is disposed at a side edge of a sheet;

[Explanation of symbols]

 1. Cassette 2. Paper 3. Paper feed roller 4. Detection member 5. Reflective member 6. Vertical line 7. Optical path 8. Bottom plate 9. Light emitting unit 10. Light receiving section

Claims (6)

[Claims] A light-emitting member, a light-receiving member, and a light-reflecting member; and a light-emitting member that reflects light from the light-emitting member. A sheet near-end detecting device, wherein an optical path that reflects and reaches a light receiving member is blocked when there is enough paper stored in a paper storage unit, and is opened when the number of papers is low. 2. The paper according to claim 1, wherein the light emitting member is arranged so that light is obliquely incident on the paper surface when there is sufficient paper stored in the paper storage unit. Near-end detection device. 3. The sheet near-end detecting device according to claim 2, wherein the light emitting member and the light receiving member are arranged on the image forming apparatus main body side, and the reflecting member is arranged on the sheet storing portion. 4. The paper near-end detecting device according to claim 2, wherein the light-emitting member, the light-receiving member, and the reflection member are arranged on a rear end side of the paper storage portion. 5. The light-emitting member and the light-receiving member are positioned above the paper container so that their surfaces face downward.
The light from the light emitting member is disposed so as to diagonally cut the rear edge of the sheet when there is sufficient paper, and the reflecting member is disposed on the rear bottom surface of the paper container. Paper near-end detection device according to 1. 6. The light-emitting member and the light-receiving member are positioned so that their surfaces face downward above the paper storage unit.
2. The paper near-end detecting device according to claim 1, wherein the light from the light emitting member is disposed so as to diagonally cut the side edge of the paper when there is sufficient paper.