JPH04197924A - Paper supply cassette - Google Patents

Abstract

PURPOSE:To obtain appropriate pressing force corresponding to the size of sheets by enlarging the pressing force of the sheet to a paper feed roller at the time of a placing plate being in a first position for placing large size sheets, and minimizing the pressing force at the time of switching the placing plate to a second position for placing small size sheets. CONSTITUTION:When a placing plate 4 is in a first position, the whole placing plate 4, that is, a front placing plate 4a and a rear placing plate 4b as an integral body, can be oscillated vertically around the rear part side of the front placing plate 4a as the center, so that the weight of the rear placing plate 4b and the rear half side weight of large size sheets positioned on the rear placing plate 4b 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 the 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 energizing mechanism 5, and this results in enlarging the pressing force of the sheets to a paper feed roller.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a rear passenger board in which a board provided in a cassette case is pivotally connected to a front board and the rear part of the board so as to be vertically swingable. The front mounting plate is configured to be vertically swingable around its rear side, and the front mounting plate is biased upward between the front mounting plate and the cassette case. A biasing means is provided, a rear edge regulating device for small-sized paper is provided on the lower surface of the rear mounting plate, and the rear mounting plate is expanded to the rear of the front mounting plate in a first position for loading large-sized paper. The present invention relates to a paper feed cassette configured to be able to freely switch to a second position for loading small-sized sheets in which the rear loading plate is rotated upward and superimposed on the front loading plate.

[Conventional technology]

This type of paper feed cassette is already known from Japanese Utility Model Application Publication No. 62-65429.

When feeding large-sized paper, this paper cassette expands the rear loading plate behind the front loading plate to increase the length of the entire loading plate in the paper feeding direction. , large-sized paper can be placed in a predetermined position, and when the paper to be fed is small-sized paper, flip the rear loading plate to the front loading plate and place it on top of the front loading plate. By folding it into
A rear edge regulating device for small-sized paper provided on the lower surface of the rear loading plate faces upward, allowing small-sized paper to be placed in a predetermined position.

However, the conventional paper feed cassette has room for improvement in the following points.

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 pushed to the main body of the image forming apparatus by means of a biasing means provided between the loading plate and the cassette case. The type of paper that is pressed by the paper feed roller, rotates, and works with double feed prevention claws, double feed prevention pads, etc. to feed sheets one by one starting from the top layer, or the paper feed roller If there is too much or too little pressing force (contact pressure) on the paper against the paper, it may cause paper feeding failure (paper jam) or double feeding (double sheet feeding). For example, when the paper to be fed is large-sized paper, the contact area between the sheets is large, so if the paper feed rollers are not strongly pressed, the paper feed rollers tend to slip, which tends to cause paper feeding failures. On the other hand, when the paper to be fed is small-sized paper, unless the pressing force against the paper feed roller is weakened, the frictional resistance between the paper sheets will increase, and double-sheet feeding will likely occur.

However, in the above-mentioned conventional paper feed cassette, in the first posture for loading large-sized paper, in which the rear loading plate is expanded to the rear of the front loading plate, the rear end edge of the rear loading plate is always The structure is such that the weight of the large-sized paper that comes into contact with the bottom plate of the cassette case and is added to the rear mounting plate is supported by the bottom plate of the cassette case.

Therefore, regardless of whether the loading plate is in the first position for loading large-sized paper or the second posture for loading small-sized paper, the biasing means Only the weight of the front loading board, which is located further forward than the paper feed roller, acts, and the pressing force of the paper against the paper feed roller is approximately constant. was likely to occur.

[Problem to be solved by the invention]

The present invention has improved the above-mentioned points, and its purpose is to increase the pressing force of the paper against the paper feed roller when the loading plate is in the first position for loading large-sized paper, and to reduce the When switching to the second position for loading size paper, the pressing force can be reduced, thereby making it possible to obtain an appropriate pressing force depending on the paper size.

[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 present invention is that, in the paper feed cassette described at the beginning, the abutment part that prevents the rear mounting plate in the first attitude from rotating downward relative to the front mounting plate is located at the front. Provided between the passenger board and the rear passenger board, the first
The rear passenger board in the posture is configured to be able to vertically swing integrally with the front passenger board around the rear side of the front passenger board.

[Effect]

According to the above configuration, when the boarding board is in the first position, the entire boarding board, that is, the front boarding board and the rear boarding board are integrated, and the rear side of the front boarding board is Since the center can swing up and down, the weight of the rear mounting plate and the weight of the rear half of the large size paper located on the rear mounting plate act downwards behind the center of swing, causing the In front of the center of motion, it acts upward as a force couple.

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

When feeding small size paper, move the loading plate to the second
Since the position is changed, the above-mentioned couple is eliminated, and furthermore, the rear mounting plate overlaps the front mounting plate, and the weight of the rear mounting plate is added to the front mounting plate, increasing the downward force. It turns out.

Therefore, the pressing force of the paper against the paper feed roller is reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

The drawing shows a paper feed cassette used by being loaded into the main body of an image forming apparatus such as a copying machine. The illustrated paper feed cassette can accommodate large size paper and small size paper, for example, B4 and 85 size (or A3 and A4 size) paper, and has a bottom plate 1a, a front plate 1b, a rear plate 1c, and a left and right side plate. Side plate 1d, l
d, a pair of left and right side end regulators 2, 2 erected inside the cassette case 1, and a pair of left and right heavy weights connected above the front ends of the side end regulators 2, 2. A feed prevention claw 3゜3 and a mounting plate 4 provided inside the cassette case l
and a biasing means 5 consisting of a compression coil spring or the like provided between the front half side of the mounting plate 4 and the bottom plate la of the cassette case 1.
, 5.

The boarding plate 4 is composed of a front boarding board 4a and a rear boarding board 4b pivotally connected to the rear part of the board via a hinge 6 so as to be able to swing vertically. The fulcrum shaft 6a of the hinge 6 has both ends rotatably supported by the side end restrictors 2.2, and the front mounting plate 4a is configured to be able to swing up and down about the fulcrum shaft 6a. .

The board 4 is, as shown in FIGS. 1 and 2,
The rear loading plate 4b is expanded to the rear of the front loading plate 4a in the first posture for loading large size paper, and the rear loading plate 4b is rotated upward as shown by the arrow in FIG. As shown in FIG. 3, the configuration is such that it can be freely switched to a second position for loading small-sized sheets superimposed on the front loading plate 4a.

A trailing edge regulating device 7 for large-sized paper is provided upright on the rear end of the upper surface of the rear mounting plate 4b, and a trailing edge regulating device 8 for small-sized paper is provided on the front end side of the lower surface of the rear mounting plate 4b. ing. The rear end restrictor 7 is inserted between the front mounting plate 4a and the front plate 1b of the cassette case 1 when the mounting plate 4 is switched to the second position.

A contact portion is provided between the front mounting plate 4a and the rear mounting plate 4b to prevent the rear mounting plate 4b in the first attitude from rotating downward relative to the front mounting plate 4a. 9 is provided, and the rear riding plate 4b in the first attitude is configured to be able to vertically swing together with the front riding plate 4a about the fulcrum shaft 6a.

The illustrated contact portion 9 has a pair of left and right protrusions 9a, 9a erected on both sides of the front end of the rear surface of the rear mounting plate 4b.
When in the first position, the tips of the protrusions 9a, 9a are configured to come into contact with the back surface of the front mounting plate 4a to prevent the rear mounting plate 4b from rotating downward. On the other hand, when the projections 9a, 9a are provided at the rear end of the back surface of the front mounting plate 4a and are in the first posture, the projections 9a.

The tip end of 9a may be configured to abut against the back surface of rear mounting plate 4b. Further, a protrusion facing the rear end restrictor 8 is provided at the rear end of the back surface of the front riding plate 4a, and when the front riding plate 4a is in the first position, the protrusion abuts the rear end restrictor 8 and the rear board is mounted. Board 4b
It may be configured to prevent downward rotation of the.

According to the above embodiment, as shown in FIG. 6(a), when the paper to be fed is large size paper a, the loading plate 4 is in the first attitude, and the front loading plate 4a and the rear Since the riding board 4b is integral and can swing up and down about the fulcrum shaft 6a, the weight of the rear riding board 4b and the weight of the rear riding board 4b are located behind the fulcrum shaft 6a, which is the center of swing. A downward force F1 due to the weight of the rear half of the large size paper a located above acts, and an upward force F2 acts as a couple in front of the fulcrum shaft 6a.
acts.

Since this upward force F2 is added to the lifting force by the urging means 5.5, the pressing force (contact pressure) of the paper a against the paper feed roller lO becomes large, and the pressing force when using the large size paper a becomes large. Paper feeding failures due to insufficient pressure are prevented.

As shown in FIG. 6(b), when the paper to be fed is a small size sheet, the mounting plate 4 is switched to the second position, so the above-mentioned couple is eliminated, and the rear mounting plate 4b is The weight of the rear mounting plate 4b superimposed on the front mounting plate 4a is added to the front mounting plate 4a, and the downward force acting on the biasing means 5 increases.

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

In addition, in the above embodiment, the center of swing of the front mounting plate 4a,
Although the pivot connection point (fulcrum shaft 6a of the hinge 6) of the front mounting plate 4a and the rear mounting plate 4b is aligned, the front mounting plate 4
The center of swing a may be located forward or rearward of the pivot connection point between the front riding plate 4a and the rear riding plate 4b. In this case, the fulcrum shaft 6a of the hinge 6 is not supported by the side end regulators 2, 2, but the shaft dedicated to the swing center is supported by the side end regulators 2.2.

Further, in the above embodiment, the large size paper a is twice the size of the small size paper, or the paper feed cassette accommodates paper of sizes that are not related in this way, for example, B4 size and A4 size. In this case, a configuration for adjusting the position of the side end regulating device 2.2 is required, and furthermore, a part of the front mounting plate 4a is provided with a structure for switching the mounting plate 4 to the second posture. At this time, an opening is formed into which the trailing edge regulating device 7 for large-sized paper enters.

〔Effect of the invention〕

The present invention has the above-described configuration, and when the loading plate is in the first position for loading large-sized paper, the pressing force of the paper against the paper feed roller is increased, and the second position for loading small-sized paper is increased. When switching to the posture, the pressing force becomes small, so it is possible to obtain an appropriate pressing force depending on the paper size.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view of the paper feed cassette with a part of the cassette case cut away, and FIG. 2 is a longitudinal cross-section of the paper feed cassette when the loading plate is in the first position. 3 is a vertical sectional side view of the paper feed cassette when the loading plate is in the second position, FIG. 4 is a plan view of the main part, FIG. 5 is a configuration diagram of the contact part, and FIG. 6 (a) and (b) are action diagrams. I... Cassette case, 4... Mounting board, 4a...
Front mounting plate, 4b... Rear mounting plate, 5... Biasing means, end... Rear end regulating device, 9... Contact portion.

Claims (1)

[Claims] The mounting plate provided inside the cassette case is composed of a front mounting plate and a rear mounting plate pivotally connected to the rear of the front mounting plate so as to be able to swing vertically, and the front mounting plate is centered on the rear side. A biasing means for urging the front loading plate upward is provided between the front loading plate and the cassette case, and a biasing means is provided between the front loading plate and the cassette case, and a biasing means for urging the front loading plate upward is provided on the lower surface of the rear loading plate. A first position for loading large-sized paper is provided with an edge control device, and the rear loading plate is expanded to the rear of the front loading plate, and the rear loading plate is rotated upward to place it on the front loading plate. In a paper feed cassette that is configured to be able to switch freely between a second position for loading stacked small-sized paper, the rear loading plate in the first position is prevented from rotating downward relative to the front loading plate. A blocking abutting portion is provided between the front riding plate and the rear riding plate, so that the rear riding plate in the first attitude is connected to the front riding plate around the rear side of the front riding plate. A paper feed cassette characterized in that it is configured to be able to swing up and down as one unit.