JPH04361932A - Detecting device for residual quantity of recording sheet - Google Patents

Abstract

PURPOSE:To provide a detecting device for a residual quantity of recording sheet capable of recognizing the replenishing timing of the recording sheet before the remaining quantity of the sheet is out. CONSTITUTION:A detecting device for a residual quantity of recording sheet comprises; a position indicating member 8 provided with a position indicating mark on its display panel while the mark is moving in compliance with the motion of a recording sheet loading plate 2 rocked or elevated according to the quantity decrease of the recording sheet, and is optically recognizable, light radiation means 21, 22 for emitting light on the display panel of the position indicating member 8; and a plurality of light receiving elements for receiving reflected light from a plurality of different detection ranges set across the distance in the moving direction of the display panel of the position indicating member 8, and detects the residual quantity of the recording sheet according to the output detected by each light receiving element.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording paper remaining amount detection device for an image forming apparatus such as a printer or a copying machine.

0002

[Prior Art] Conventional copying machines generally detect when all the recording paper in a recording paper storage such as a paper cassette or paper feeding deck is used up, but how much recording paper is left in the recording paper storage? It is not detected whether there are any leftovers.

0003

[Problem to be solved by the invention] For this reason, the user
It is common for a user to suddenly run out of recording paper during a copying operation, stop the copying operation, and then find out that the recording paper has run out and replenish the recording paper.

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording paper remaining amount detecting device that can determine when to replenish the recording paper before the recording paper runs out.

[0005]

[Means for Solving the Problems] The recording paper remaining amount detection device according to the present invention moves with the movement of a recording paper mounting plate that swings or goes up and down as the number of recording papers decreases, and can be optically recognized. A position display member having a position display mark attached to the display surface, a light irradiation means for irradiating light onto the display surface of the position display member, and a plurality of different detections set over the length of the display surface of the position display member in the moving direction. It is characterized in that it includes a plurality of light receiving elements for respectively receiving reflected light from the range, and detects the remaining amount of recording paper based on the detection output of each light receiving element.

[0006]

[Operation] Since the position display member moves as the recording paper mounting plate moves, the remaining amount of recording paper can be determined by knowing the position of the position display mark attached to the position display member. The position of the position display mark is detected based on the detection output of a plurality of light receiving elements for respectively receiving reflected light from a plurality of different detection ranges set over the length of the display surface of the position display member in the moving direction, This allows the remaining amount of recording paper to be detected.

[0007]

Embodiments Hereinafter, embodiments in which the present invention is applied to a copying machine will be described with reference to the drawings.

In FIGS. 1 and 2, a paper feed cassette 1 mounted on a main body of a copying machine (not shown) supports a recording paper mounting plate 2 so as to be swingable about its rear end. The front part of the recording paper mounting plate 2 is always urged upward by a spring 3 provided between the front part of the recording paper mounting plate 2 and the bottom wall of the paper feed cassette 1. A plurality of recording papers (not shown) are placed on the recording paper mounting plate 2 in an overlapping state, and as the number of recording papers decreases, the recording paper mounting plate 2 is moved backward by the biasing force of the spring 3. It swings clockwise (in the direction indicated by arrow A in FIG. 1) about the end.

A pair of upper and lower pulleys 4 and 5 extending in the front-rear direction are rotatably attached to the front end of the left side wall of the paper feed cassette 1 via support members 6 and 7. An endless position indicating belt 8 is placed around both pulleys 4 and 5. A connecting rod 9 fixed to the recording paper mounting plate 2 is connected to the position display belt 8, and when the recording paper mounting plate 2 swings around its rear end, the position display belt 8 moves accordingly. do.

The outer surface of the position display belt 8 is colored so that half of the length of the position display belt 8 is black and the other half is white. Cross line B for the black part, W for the white part,
These boundary lines are indicated by the symbol L, respectively.

From the front end of the left side wall in the paper feed cassette 1, light is irradiated from the left side of the paper feed cassette 1 onto the display surface which is the left facing surface of the position display belt 8, and the display surface of the position display belt 8 is illuminated from the left side of the paper feed cassette 1. A window 10 is formed to transmit reflected light from the paper feed cassette 1 to the left side.

On the main body side of the copying machine, there are floodlights 21 and 22 made up of a pair of front and rear light emitting diodes for irradiating light from an oblique direction onto the display surface of the position display belt 8 through the window 10.
(light irradiation means) and lenses 23 and 24 for projection are arranged.

Further, on the copying machine main body side, an image sensor 25 such as a CCD and a light receiving lens 26 are provided at a position directly facing the display surface of the position display belt 8. The image sensor 25 includes a plurality of light receiving elements for receiving reflected light from a plurality of detection ranges set over the length of the display surface of the position display belt 8 in the vertical direction.

[0014] Floodlights 21, 22 and image sensor 2
5 is driven when the copying machine is powered on and the paper feed cassette 1 is installed in the copying machine. When the recording paper is almost full, the black part B of the position display belt 8
The boundary line L between the position display belt 8 and the white portion W is located above the center of the height of the display surface of the position display belt 8. When the remaining amount of recording paper is half of the full state, the boundary line L between the black portion B and the white portion W of the position display belt 8 is located at the center of the height of the left facing surface of the position display belt 8. When the remaining amount of recording paper becomes less than half of the full state, the boundary line L between the black portion B and the white portion W of the position display belt 8 is located below the center of the height of the left facing surface of the position display belt 8. . That is, the boundary line L between the black portion B and the white portion W of the position display belt 8 moves downward as the remaining amount of recording paper decreases.

FIG. 3 shows the output waveform of the image sensor 25.

The output of the image sensor 25 consists of a sensing portion b of a black portion B having a relatively low output voltage and a sensing portion w of a white portion W having a relatively high output voltage. As the remaining amount of recording paper decreases, the boundary line L between the black part B and the white part W of the position display belt 8 moves downward, so that the detection part b of the black part B also appears in the output of the image sensor 25.
The boundary between the white portion W and the detection portion w changes.

The detection output of the image sensor 25 is transmitted to the control section (
(not shown). The control section determines the remaining amount of recording paper in the paper feed cassette 1 based on the detection output of the image sensor 25, and displays the remaining amount of recording paper on a display (
(not shown). Therefore, from this display, the user can know the amount of recording paper remaining in the paper feed cassette 1, and can know when to replenish the recording paper before the recording paper runs out.

FIG. 4 shows a modification of the position indicating belt.

The outer surface of the position display belt 81 is color coded such that half of the length of the position display belt 8 is black and the other half is gray. The black part is indicated by a cross line B, the gray part is indicated by a diagonal line G, and the boundary line between these is indicated by a symbol L. Furthermore, a plurality of white barcodes W are attached to the gray portion G at predetermined intervals in the length direction of the position display belt 81.

The output waveform of the image sensor 25 when this position indicating belt 81 is used is as shown in FIG. That is, the output of the image sensor 25 is a detection part b of the black part B where the output voltage is relatively low, a detection part g of the gray part G where the output voltage is relatively high, and a detection part of the white barcode W where the output voltage is the highest. It consists of part w.

When such a position display belt 81 is used, the interval or pattern of the white barcode W can be set differently for each type of paper feed cassette with a different recording paper size, so that the position of the image sensor 25 can be adjusted. Based on the output, the remaining amount of recording paper can be detected, and the type of paper feed cassette can also be determined.

[0022]

According to the present invention, it is possible to know when to replenish recording paper before the recording paper runs out.

[Brief explanation of the drawing]

FIG. 1 is a horizontal sectional view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a schematic configuration of an embodiment of the invention.

FIG. 3 is a waveform diagram showing an output waveform of an image sensor.

FIG. 4 is a perspective view showing a modification of the position indicating belt.

FIG. 5 is a waveform diagram showing an output waveform of an image sensor. 1 Paper feed cassette 2 Recording paper placement plate 8 Position display belt 21 Light emitter 22 Light emitter 25 Image sensor 81 Position display belt

Claims (1)

[Claims] 1. A position display member having an optically recognizable position display mark attached to a display surface, which moves with the movement of a recording paper mounting plate that swings or moves up and down as the number of recording papers decreases; A light irradiation unit that irradiates light onto the display surface of the position display member, and a plurality of light receiving elements that respectively receive reflected light from a plurality of different detection ranges set over the length of the display surface of the position display member in the moving direction. A recording paper remaining amount detection device that detects the remaining amount of recording paper based on the detection output of each light receiving element.