JPH04197927A - Paper supply cassette - Google Patents

Abstract

PURPOSE:To obtain appropriate pressing force corresponding to the size of sheets by disposing a placing plate, provided with a sheet rear end regulating means fitted to be capable of longitudinally changing its position according to the sheet size, inside a cassette case in such a way as to be capable of oscillating vertically around the paper feeding direction intermediate part of the placing plate as the center. CONSTITUTION:When sheets of large size are placed on a placing plate 5 with its oscillating center positioned at the paper feeding direction intermediate part of the placing plate 5, the weight of the part positioned at the rear side of oscillating center of the placing plate 5 and the weight of the large size sheet rear half side positioned on this rear side part of the placing plate 5 act downward on the rear side of the oscillating center while acting upward as a couple on the front side of the oscillating center. In the case of large size sheets, the upward force acting as the couple on the front side of the oscillating center is thereby added to the lifting force by an energizing means 6, and this results in enlarging the pressing force of the sheets to a paper feed roller.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a mounting board in which a paper trailing edge regulating device is attached to which the position can be freely changed in the front and back direction according to the paper size, in a cassette case. The present invention relates to a paper feed cassette that is vertically swingable and includes a biasing means for upwardly biasing the front side of the loading plate between the front side of the loading plate and the cassette case.

[Conventional technology]

Conventionally, this type of paper feed cassette has the following structure, as shown in FIG.
The mounting plate 5 was configured to vertically swing around its rear end p.

Therefore, when the paper to be fed is large size paper a,
Paper feed roller 9
The pressing force (contact pressure) of the paper against the paper became small, and paper feeding failures (paper jams) and double feeding (double sheet feeding) were likely to occur due to excessive or insufficient pressing force.

That is, when the paper feed cassette is loaded into the main body of an image forming apparatus such as a copying machine, the paper in the paper feed cassette is placed on the loading plate 5.
The biasing means 6 provided between the cassette case L and the paper feed roller 9 is pressed against the paper feed roller 9 provided in the main body of the image forming apparatus, and the rotation of the paper feed roller 9 causes contact with the double feed prevention claw, double feed prevention pad, etc. If the sheets are fed one by one starting from the top layer of paper by cooperation, or if the pressing force (contact pressure) of the paper against the paper feed roller 9 is too much or too little, it may cause paper feeding failure or double feeding. It may happen. For example, when feeding large-sized paper, the contact area between the sheets is large, so if you do not press strongly against the paper feed roller 9, the paper feed roller 9 will tend to slip and paper feeding failures may occur. . On the other hand, when the paper to be fed is small-sized paper, unless the pressing force against the paper feed roller 9 is weakened, the frictional resistance between the paper sheets will increase and double-sheet feeding will likely occur.

However, as mentioned above, conventional paper feed cassettes
Since the mounting plate 5 was structured to swing around the rear end p, when a large-sized paper a is placed on the mounting plate 5, as shown by the imaginary line in FIG. The downward force acting on 6 is compared to when a small size paper tray is placed.
The weight of the rear half of the large size paper a located behind the rear end of the small size paper sheet is larger, and the weight of the paper feed roller 9 increases accordingly.
Since the pressing force of the paper a against the paper decreases, paper feeding failures are likely to occur.

Also, when a small size paper tray is placed on the loading board 5,
As a result of the weight of the latter half of the large size paper mentioned above being reduced,
The pressing force of the paper tray against the paper feed roller 9 becomes excessive, and double-sheet feeding is likely to occur.

[Problem to be solved by the invention]

The present invention has been made with the above points in mind, and
The first purpose is to increase the pressing force against the paper feed roller when large-sized paper is placed on the loading board, and to reduce the pressing force when small-sized paper is placed on the loading board. The objective is to obtain an appropriate pressing force. The second purpose is to make the vertical width of the cassette case as small as possible, and to make it easy to visually confirm from the outside when the remaining amount of paper stored in the paper feed cassette is decreasing. There is a particular thing.

[Means to solve the problem]

The technical means taken by the present invention to achieve the above object are as follows.

That is, the feature of the first invention is that a mounting plate, on which a paper trailing edge regulating device is attached so that its position can be freely changed in the front and back direction according to the paper size, is placed in the cassette case at a position midway in the paper feeding direction of the mounting plate. The device is provided so as to be vertically swingable about the mounting plate, and a biasing means for biasing the front side of the mounting plate upward is provided between the front side of the mounting plate and the cassette case.

A feature of the second invention is that, in addition to the above configuration, an opening is formed in the bottom plate of the cassette case through which the rear end of the mounting plate can be inserted and removed.

[Effect]

According to the configurations of the first invention and the second invention, since the center of swing of the mounting plate is located at the intermediate portion of the mounting plate in the paper feeding direction (that is, at the 11th point between the front end and the rear end of the mounting plate, When large-sized paper is placed on the loading plate, the weight of the portion of the loading plate located behind the center of swing, and the weight of the second half of the large-sized paper located above that portion, are measured behind the center of swing. The weight on the side acts downward,
It acts upward as a couple in front of the center of swing.

Therefore, when the paper to be fed is large-sized paper, the upward force acting as a couple in front of the swing center or the lifting force by the biasing means is added, pushing the paper against the paper feed roller. Pressure (contact pressure) increases.

When the paper to be fed is a small size paper, the couple due to the weight of the latter half of the large size paper disappears, and the downward force acting on the biasing means increases accordingly.

Therefore, the pressing force of the paper against the paper feed roller becomes small.

According to the configuration of the second invention, as the remaining amount of paper in the paper feed cassette decreases, the rear end of the mounting plate gradually descends, and extends downward from the opening formed in the bottom plate of the cassette case. It will be exposed.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 1 and 2 show an embodiment of the first invention.

This paper feed cassette is a so-called universal paper feed cassette that can accommodate paper of several sizes with different vertical and horizontal dimensions. a cassette case 1 consisting of a cassette case 1; a pair of left and right side end restrictors 2, 2 provided within the cassette case l so as to be freely changeable in position in the left-right direction; A pair of left and right double-feed prevention claws 3, 3, a trailing edge restrictor 4, a loading plate 5 attached to the rear edge regulator 4 so that its position can be changed in the front and rear directions according to the paper size, the front half side of the loading plate 5, and a cassette case l. It is provided with biasing means 6, 6 consisting of a compression coil spring or the like provided between the bottom plate 1a and the bottom plate 1a. The mechanism for changing the position of the side end restrictors 2, 2 in the left-right direction and the mechanism for changing the position of the rear end restrictor 4 in the front-rear direction are well known and will not be described here.

The middle part of the mounting plate 5 in the paper feeding direction (meaning the position between the front end and the rear end, and does not necessarily have to be the center) is as follows:
It is supported by a pair of left and right support plates 7.7 erected on the bottom plate 1a of the cassette case l via a pivot shaft 8.8, and the mounting plate 5 swings up and down about the pivot shafts 8, 8. It is configured so that it can be done.

According to the above embodiment, the loading plate 5 swings up and down about the pivot shaft 8 at the intermediate portion in the paper feeding direction, so that
As shown in b), when the paper to be fed is large-sized paper a, the weight of the rear half of large-sized paper a located behind the pivot shaft 8, which is the center of swing of the loading plate 5, A downward force F1 acts on the rear side of the pivot shaft 8, and an upward force F2 acts as a couple on the front side of the pivot shaft 8.

Since this upward force F2 is added to the lifting force by the urging means 6.6, the pressing force (contact pressure) of the paper a against the paper feed roller 9 becomes large, and the pressing force when using the large size paper a increases. Paper feeding failures due to insufficient pressure are prevented.

Furthermore, as shown in FIG. 3(b), when the paper to be fed is small-sized paper, the above-mentioned couple disappears, and the downward force acting on the biasing means 6.6 increases accordingly. become.

Therefore, the pressing force of the paper tray against the paper feed roller 9 is reduced, and double feeding (double sheet feeding) of paper trays due to excessive pressing force when using a large size paper tray is prevented.

FIG. 4 shows an embodiment of the second invention. This example is
This embodiment has the same structure as the embodiment of the first invention, but is characterized in that the bottom plate 1a of the cassette case 1 has an opening 10 through which the rear end of the mounting plate 5 can be inserted and removed.

According to this embodiment, the depth of the cassette case l can be made shallow, and as the remaining amount of paper in the paper feed cassette decreases, the rear end of the mounting plate 5 gradually descends. , is finally exposed downward through the opening 10.

Therefore, by seeing that the rear end of the mounting plate 5 is exposed through the opening 1o, the amount of remaining paper can be determined to the extent that paper needs to be replenished without pulling out the paper feed cassette from the main body of the image forming apparatus. The reduction can be easily confirmed visually. The other configurations and operations are the same as those in the first embodiment of the invention, so their explanations will be omitted.

In addition, in each of the above embodiments, the side end regulating tool 2
．． Although the first and second inventions have been described, the universal paper feed cassette configured in this manner is referred to as a side end regulating tool 2. Of course, the present invention can also be applied to a type of paper feed cassette whose position in the left and right direction is fixed.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it can achieve the following effects.

According to claim 11, when a large size paper is placed on the loading plate, the pressing force against the paper feed roller becomes large, and when a small size paper is placed on the mounting plate, the pressing force becomes small.
It is possible to obtain an appropriate pressing force depending on the paper size.

According to claim (2), in addition to the above effects, the vertical width of the cassette case can be made as small as possible, and the remaining amount of paper can be reduced without pulling out the paper feed cassette from the main body of the image forming apparatus. This has the effect of making it easy to visually confirm what has been done.

[Brief explanation of the drawing]

1 to 3 (A) and (B) show an embodiment of the first invention, FIG. 1 is a partially cutaway perspective view of the paper feed cassette, and FIG. 2 is a longitudinal cross-section of the paper feed cassette. Side view, Figure 3 (a),
(b) is an action diagram. FIG. 4 is a vertical sectional side view of a paper feed cassette/slot showing an embodiment of the second invention. FIG. 5 is an explanatory diagram of a conventional example. DESCRIPTION OF SYMBOLS 1... Cassette case, la... Bottom plate, 4... Rear end regulating device, 5... Mounting plate, 6... Biasing means, 8...
- Swing center (pivot axis), 10...opening.

Claims (2)

[Claims] (1) Place the mounting plate, on which the paper trailing edge regulating device is attached so that its position can be freely changed in the front and rear directions according to the paper size, in the cassette case, and swing it up and down about the middle part of the mounting plate in the paper feeding direction. A paper feed cassette, which is movably provided, and is provided with a biasing means for upwardly biasing the front side of the loading plate between the front side of the loading plate and the cassette case. (2) Place the mounting plate, on which the paper trailing edge regulating device is attached so that its position can be freely changed in the front-back direction according to the paper size, in the cassette case, and swing it up and down about the middle part of the mounting plate in the paper feeding direction. A biasing means for urging the front side of the mounting plate upward is provided between the front side of the mounting plate and the cassette case, and the rear end of the mounting plate is provided on the bottom plate of the cassette case. A paper feed cassette characterized by forming an opening into which a portion can be inserted and removed.