JPH0680275A - Residual amount of paper detecting device of copying machine - Google Patents

Abstract

PURPOSE:To detect accurately the residual amount of paper sheets in a paper sheet tray installed in a copying machine. CONSTITUTION:The paper sheet feeding device 100 of a copying machine has a tray 110. The tray 110 has a bottom plate 120 at the bottom 114, and the bottom plate 120 is swayed upward making a fulcrum 122 as the center, and squeezes the uppermost part of the paper sheets 300 to a feed roll 200. The arm 132 of a lifter 130 to rotate in the direction of the arrow B driven by an actuator is abutted to the lower surface of the bottom plate 120, and pushes up the bottom plate 120. The rotation amount of the lifter 130 is detected by an encoder 150. From the swaying angle A of the bottom plate 120, the height H of the paper sheets is operated, and the result is displayed in a display device 170 as the residual amount of the paper sheets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remaining amount detecting device for a paper feed tray in a copying machine or the like.

[0002]

2. Description of the Related Art A copying machine is equipped with a paper feeding tray device capable of setting copying papers having various capacities. Second
The figure shows the basic configuration of the sheet feeding device. The paper tray 12 of the paper feed tray device 11 can stack a large number of copy papers 13 of the same size. The sheet mounting table 12 can be moved up and down by an elevator mechanism (not shown). In the state where copying is performed, the uppermost layer of the copy paper 13 is always in contact with the paper feed belt 15. When the paper feed belt 15 rotates in this state, the copy paper 13 is fed into the main body 16 of the copying machine. A paper guide plate 17 whose position can be laterally adjusted according to the size of the copy paper 13 is attached to the paper table 12. To set a copy sheet, the operator operates a switch (not shown) to lower the sheet tray 12 to a position immediately near the body frame 16A. Next, the position of the paper guide plate 17 is set according to the size of the copy paper 13. After that, the copy paper 13 is set on the paper table 12. Then, other switches (not shown) are operated to raise the paper tray 12.

In such a paper feed tray device, many sensors have been conventionally used. The first sensor 21 is a sensor that controls the lower limit position of the paper tray 12. The second sensor 22 is a sensor for controlling the position of the paper tray 12 so that the uppermost layer of the copy paper is kept in contact with the paper feed belt 15. The third sensor 23 is a sensor for detecting the remaining amount of the copy paper 13 based on the displacement of the paper tray 12. In addition, the fourth to sixth sensors 24-26
Are three types of copy sheets 13 placed on the sheet stand 12.
Is a sensor for detecting the size of. 4th of these
The sixth sensors 24 to 26 are copy sheets, such as B4 size, A4 size, and B5, which are selectively placed on the sheet mounting table 12.
It is arranged for each copy sheet position of the format. The copying machine discriminates the copy sheet based on the detection results of these sensors 24-26.

The present applicant has proposed a device shown in FIG. 3 in Japanese Patent Laid-Open No. 59-214046 as a device for detecting the remaining amount of paper in this kind of paper feed tray. FIG. 3 schematically shows the mechanical portion of the paper feed tray device. A stopper 41 is screwed to the center of the lower end of the paper guide plate 17, and one end of a wire 42 is tied to this.
A part 16B of the main body of the copying machine is arranged below the sheet mounting table 12 in a protruding form, and a potentiometer 43 is fixedly mounted on the upper surface thereof. The central portion of the wire 42 is wound around the rotary shaft 43A of the potentiometer, and the other end is attached to the weight 45 through a hole 44 provided on the upper surface. In this apparatus, when the copyboard 13 is used, the paper tray 12 is raised, and when the copy paper 13 is set, the paper guide plate 17 is moved to the left or right in the figure.
The distance between the stopper 41 and the rotary shaft 43A varies, and the potentiometer outputs an analog signal corresponding to this. In this apparatus, when the paper guide plate 17 is moved in accordance with the paper size at the paper feed position, the wire 42 moves and the potentiometer 43 detects this. Further, the potentiometer 43 also detects that the mounting table 12 is raised by using the paper 13. Therefore, in this apparatus, both the paper size and the remaining amount can be detected.

[0005]

However, the above-mentioned apparatus is of a type in which sheets of various sizes are accommodated in one sheet loading table, and the paper guide plate 17 and the loading table are moved. Since the wire was transmitted to the potentiometer by the wire, there was a problem that the expansion and contraction of the wire, mechanical backlash of each part, etc., deteriorated the detection accuracy. As a recent paper tray, a dedicated tray is prepared for each paper size, and a structure is adopted in which the bottom plate of the tray is urged upward to press the uppermost paper of the paper cassette against the feed roll. The present invention provides a sheet remaining amount detecting device for a sheet tray of this type.

[0006]

SUMMARY OF THE INVENTION A sheet feeding apparatus according to the present invention includes a sheet tray mounted on a copying machine for storing copying sheets, a feed roll disposed on the upper portion of the sheet tray, and a bottom portion of the sheet tray. A swingable bottom plate is provided, a rotary lifter that raises the bottom plate toward the feed roll, and an encoder that detects a rotation angle of the lifter.

[0007]

The rotation angle of the lifter and the swing angle of the bottom plate have a constant relationship, and the angle of the bottom plate has a relationship with the remaining amount of paper. Therefore, the remaining amount of paper in the tray can be calculated and displayed based on the data of the rotation angle of the lifter detected by the encoder.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the outline of the device of the present invention. A copying paper feeding apparatus, generally designated by reference numeral 100, has a rectangular tray 110. Front 111 of tray 110
A paper outlet 112 is formed in the upper part of the. Exit 11
A feed roll 200 is disposed in the vicinity of 2, and the feed roll 200 is rotated by a drive mechanism (not shown) provided on the copying machine main body side. A bottom plate 130 is disposed on the upper surface of the bottom 114 of the tray 110. This bottom plate 120 has a fulcrum 12
The end portion of the tray on the front portion 111 side is attached so as to swing upward with the center at 2.

The copy paper 300 is accommodated in the tray 110, and the uppermost paper 300a is sent out toward the exit 112 by the feed roll 200. On the copier body side,
The lifter 130 is equipped. The lifter 130 is rotationally driven from, for example, a motor via a gear transmission or the like. The lifter 130 has an arm 132, and the tip of the arm 132 contacts the lower surface of the bottom plate 120. Therefore, the lifter 1
When the arm 30 rotates, the arm 132 pushes up the bottom plate 120 of the tray 110. By this operation, the bottom plate 120 swings upward about the fulcrum 122 as indicated by an angle A.

The rotary shaft 134 of the lifter 130 is connected to the encoder 150. The encoder 150 has a rotating shaft 134.
It has a function of detecting the rotation amount (rotation angle) B of. Since the rotation amount of the rotating shaft 134 is the same as the rotation amount of the lifter 130, the rotation angle of the arm 132 can be detected by detecting the rotation amount of the lifter 130. The signal of the encoder 150 is sent to the display unit 170 via the line 160. The lifter 130 swings the bottom plate 120 so that the uppermost sheet 300 a of the copy sheet 300 is constantly fed by the roll 2.
Keep in contact with 00. Copying progresses, tray 1
When the paper 300 in 10 is consumed, the lifter 130 rotates in the direction of arrow B, and the swing angle A of the bottom plate 120 increases. The rotation angle B of the lifter 130 and the swing angle A of the bottom plate 120 have a certain correlation.

The remaining amount of the paper 300 in the tray 110 is grasped as the height H of the paper between the bottom plate 120 and the feed roll 200. The mounting position of the feed roll 200, the diameter of the roll, the fulcrum 122 of the bottom plate 120, and the feed roll 200
The distance dimension L to the center of rotation is mechanically specified. From these relationships, the height dimension H of the sheet 300 can be calculated based on the swing angle A of the bottom plate 120. Therefore, the rotation angle B of the lifter 130 can be detected by the encoder 150 as an analog signal or a digital signal. Based on this signal, the remaining amount of paper in 110 can be calculated, and the result is displayed on the display device 170.

[0012]

As described above, the paper feeding device of the copying machine according to the present invention directly detects the operation of the lifter for displacing the bottom plate of the tray to the feed roll side and detects the remaining amount of paper in the tray. is there. Although the lifter raises the bottom plate by the rotating arm, the rotation amount of the lifter is directly detected by using the rotary encoder, so that highly accurate detection can be achieved. Further, since only the rotary encoder is attached to the lifter, the mechanical structure can be simplified, and a highly reliable remaining paper amount detecting device can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a sheet supply device of the present invention.

FIG. 2 is an explanatory view showing a conventional paper supply device.

FIG. 3 is an explanatory view showing another conventional paper feeding device.

[Explanation of symbols]

100 paper body, 110 paper tray, 120 bottom plate, 122 fulcrum, 130 lifter, 132 arm,
150 encoders, 170 displays, 200 feed rolls, 300 sheets.

Claims (1)

[Claims] 1. A paper tray mounted on a copying machine for storing copy paper, a feed roll arranged on the top of the paper tray, a swingable bottom plate arranged on the bottom of the paper tray, and a bottom plate. A rotary lifter that raises the roll toward the feed roll, and an encoder that detects the rotation angle of the lifter,
A remaining paper amount detection device for a copying machine, which has means for calculating and displaying the remaining amount of paper in the tray based on the lifter rotation angle data detected by the encoder.