JPH02138046A - Image formation device - Google Patents

Abstract

PURPOSE:To make it possible to detect the existence of sheets and a sheet supply cassette by a reflection type sensor to realize cost reduction by making non-reflective a shutter being opened and closed by taking in and out the sheet supply cassette and a portion of a sheet loading part opposed to the reflection type sensor. CONSTITUTION:When sheets 10 are supplied and becomes zero, and the last sheet is sent out, a separating felt 6 becomes uncovered. As a result, light from a reflection type sensor 2 does not reflect on the separating felt 6, and an indicating device 10 changes the indication from 'existence' to 'lack' of the sheet. When a sheet supply cassette 14 is withdrawn out, a shutter 3 is pressed by a compression coil spring 4 to move to the left to block the reflection type sensor 2. As a result, the indicating device 10 indicates 'lack' of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to means for detecting the presence or absence of paper stacked in a cassette in an image forming apparatus.

``Prior Art'' There are two types of cassettes for image forming apparatuses: one in which the cassette is inserted parallel to the paper feeding direction, and the other in which the cassette is inserted perpendicular to the paper feeding direction. The perspective view of FIG. 7 shows an example in which a single sensor detects whether or not a paper feed cassette in the latter type is installed in the image forming apparatus, and whether there is paper in the paper feed cassette if it is installed. .

The insertion direction of the paper feed cassette is the direction of arrow A, and the paper feeding direction is the direction perpendicular to the arrow openings. The actuator 12 is rotatably supported by a shaft 21 parallel to the paper feeding direction. The shaft 21 is floatingly supported by a link (not shown) so as to be able to move up and down, and when the paper feed cassette is inserted, the shaft 21 is pushed up by the paper feed cassette, and the shutter part 12a of the actuator 12 is raised to shut off the photo interrupter 11, and The roller 16 rests on the paper in the paper feed cassette 13.

A roller 13 rotatably attached to a shaft 22 perpendicular to the shaft 21 is rotated by the paper during paper feeding. When the paper runs out, the roller 13 descends, the actuator 12 swings about the shaft 21, and the shutter portion 12a leaves the photo interrupter 11, thereby issuing a paper out signal. When the paper feed cassette is pulled out, the shutter portion 12a is lowered together with the shaft 21, similarly indicating that there is no paper.

``A difficult problem to be solved by the invention'' In order to detect the presence or absence of paper with a single sensor, the actuator must rotate in two directions: the paper feeding direction and the insertion and removal of the paper cassette. A complex floating-supported two-stage actuator was required. In addition, since the rollers are always in contact with the paper, there is a possibility that the paper feeding operation will be adversely affected in some way, and the contact pressure, location, and structure of the rollers must be studied and tested in detail when designing.

The present invention was devised to eliminate the above-mentioned drawbacks.
It is an object of the present invention to provide an image forming apparatus equipped with a paper feed cassette that does not require a complicated link mechanism, can detect paper without contacting it, and can perform stable paper feeding operation, and a means for detecting the presence or absence of paper. shall be.

``Means for Solving the Problems'' The present invention provides an image forming apparatus in which a paper cassette is installed and removed from a direction perpendicular to the paper feeding direction, in which a shutter that opens and closes in conjunction with the movement of the paper cassette is connected to a shutter that opens and closes in conjunction with the movement of the paper cassette. This image forming apparatus is provided between a paper stacking section and a reflective sensor provided on the main body of the image forming apparatus, and is characterized in that a portion of the paper stacking section facing the reflective sensor is made non-reflective.

"Embodiments" Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of the paper feeding section 15 of the image forming apparatus along the paper feeding direction, and FIG. 4 is a sectional view of the back side parallel to FIG. 1. The paper feed cassette 14 can be inserted into and removed from the paper feed section 15 from a direction perpendicular to the plane of the drawing. The paper feed cassette 14 has a middle plate 7 pushed up by the spring force of a spring 8 and a separation claw 16 on a paper loading portion in the cassette holder 1, and faces a paper feed roller 9 supported and driven on the image forming apparatus side. The middle plate 7 is provided with a separation felt 6.

The paper feeding operation is performed when the paper 18 placed on the middle plate Z (Fig. 5)
is pressed toward the paper feed roller 9 by the middle plate 7 which is urged upward by a spring force. When the paper feed roller 9 rotates counterclockwise, the uppermost paper 18 is sent out to the right, and is conveyed by a pair of feed rollers 17 into an apparatus that performs an image forming process.

2 and 3 are sectional views taken along the line AA in FIG. 1. A reflective sensor 2 is fixed downward to a stay 5 in the upper part of the paper feeding section 15 in a direction perpendicular to the paper feeding direction. The stay 5 has a rectangular tube shape, and a window 19 is provided at the bottom of the stay 5 in the optical path of the reflective sensor 2. A shutter 3 that opens and closes the optical path of the reflective sensor 2 is guided by both extended edges of the window 19 and is movable left and right. The shutter 6 is closed by a non-reflective, e.g., black light shielding part Aa that enters and exits the optical path of the reflective sensor 2, a leftmost position is determined by hitting the reflective sensor 2, a stopper part 3b that also serves as a spring seat, and a cassette holder 1.
A part of the edge for moving the body is made of 6C.

A compression coil spring 4 is inserted between the stopper part 3b and the one end 26 of the stay, and the shutter 6 is connected to the stopper part 3b.
hits the reflective sensor 2 to define the left travel limit position, and the optical path of the reflective sensor 2 is blocked by the light shielding portion 6a at the left travel limit position.

The opposing portion of the reflective sensor 2 is designed to be non-reflective when there is no paper. For this reason, as shown in FIG. 5, a separation felt 6 is pasted on the width of the middle plate 7 over the entire width of the cassette cabinet 1, and is colored, for example, black so that the light from the reflective sensor 2 is not reflected. The signal detected by the reflective sensor 2 is sent to the display device ji1o, and the signal detected by the reflective sensor 2 is sent to the display device ji1o.
The presence or absence of 4 and the presence or absence of paper are displayed.

To explain the operation of the above configuration, when the paper feed cassette 14 is inserted into the paper feed section 15 in the direction of arrow A in FIG. The compression coil spring 4 is compressed, the light shielding part 3a of the shutter 3 opens the window 19, and the light from the reflective sensor 2 is reflected by the white paper 18 and received, and the display device 1
0 - The display that used to indicate that there is no paper changes to the display that there is paper (Figure 3).

From the state shown in Fig. 6, the paper 18 loses its condyle due to paper feeding.
When the last sheet is fed out, the separation felt 6 is exposed as shown in FIG. Since the light from the reflective sensor 2 is not reflected by the separation felt 6, the display on the display device 10 changes from paper present to paper absent.

When the paper feed cassette 14 is moved to the left from the position shown in FIG. .

In the above embodiment, if the color of the black separation felt 6 is not specified, a hole 24 of a certain size or more is formed in the separation felt 6 and the middle plate 7 facing the reflective sensor 2, as shown in FIG. may be provided to prevent the reflected light from the reflective sensor 2 from returning to the reflective sensor 2 when there is no paper.

The size of the hole 24 needs to be determined experimentally based on the sensitivity of the reflective sensor 2 and the distance between the paper 18 and the reflective sensor 2.

〔Effect of the invention〕

As described above, the following effects are produced by making the shutter, which opens and closes when the paper feed cassette is inserted and removed, and the portion of the paper stacking section that faces the reflective sensor non-reflective.

(1) A single reflective sensor can detect the presence or absence of paper and the presence or absence of a paper feed cassette, resulting in cost reduction.

(2) Since the detection is performed without contacting the paper, there is no possibility of adversely affecting the paper feeding operation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIGS. 2 and 6 are AA sectional views of FIG. 1, FIG. 4 is another longitudinal sectional view parallel to FIG. 1, and FIG. FIG. 6 is a plan view of the paper feed cassette, FIG. 6 is a plan view of another embodiment, and FIG. 7 is a perspective view of a conventional example. 1. Cassette holder 2. Reflective sensor 3. e-shutter 3a. Light shielding part 3b. Stopper part 6C.
Part of the edge 4. Compression coil spring 511. Stay 6
Separation felt 7 Middle plate 8 Spring 9 Paper feed roller 10 Display device 11 Photo interrupter 12 Actuator 12a Part of the shutter
13... Roller 14... Paper feed cassette 15... Paper feed section 16... Separation claw 17... Feed roller pair 18... Paper 19... Window 21. 22... Shaft 23II... One end of the stem 24... Hole.

Claims (1)

[Claims] 1. In an image forming apparatus in which a paper feed cassette is installed and removed from a direction perpendicular to the paper feeding direction, a shutter that opens and closes in conjunction with the movement of the paper feed cassette is provided on the paper loading section in the paper feed cassette and on the main body of the image forming apparatus. What is claimed is: 1. An image forming apparatus that is provided between a reflective sensor and a reflective sensor, and is characterized in that a portion of a sheet loading section facing the reflective sensor is made non-reflective.