JP4489993B2 - Paper cassette - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feed cassette that is installed in an image forming apparatus such as a facsimile machine, a copier, or a printer and that stacks and stores sheets used for image formation.
[0002]
[Prior art]
7 is a plan view showing an example of a conventional paper feed cassette, FIG. 8 is a cross-sectional view of the conventional paper feed cassette of FIG. 7, 1 is a box-shaped cassette frame, and 2 is a paper placement surface 1a. An end fence 3, which is installed upstream of the paper feeding direction and regulates the position of the trailing edge of the paper, is installed opposite to both sides of the paper placement surface 1a to regulate the position of the side of the paper. The pair of side fences 4 includes a bottom plate on which the other end is pivotally supported by the support shaft 5 so that one end thereof can be rotated upward from the bottom surface of the sheet placing surface 1a, and sheets are stacked on the upper surface. Is a separation claw which is provided so as to be engaged with both corners on the downstream side in the paper feeding direction of the paper and acts to separate and feed the paper one by one, and 7 is a spring which urges the bottom plate 4 upward. is there.
[0003]
In the paper feeding cassette, when the paper is replenished, the bottom plate 4 is locked at a lower position by a lock mechanism (not shown). In this state, the user sets paper from the paper placement surface 1a in the cassette frame 1 to the bottom plate 4. Thereafter, the end fence 2 and the side fence 3 are moved in order to restrict the position of the sheet to a predetermined position on the sheet placing surface 1a according to the size, and the end fence 2 and the side fence are disposed at the rear end and both sides of the sheet. Align with 3.
[0004]
During paper feeding, the lock to the bottom plate 4 by the locking mechanism is released, the bottom plate 4 is rotated upward by the spring 7, the sheet is raised with the rotation of the bottom plate 4, and the top surface of the uppermost sheet is not shown. In contact with the paper roller, both corners of the paper are respectively locked to the separation claws 6. The uppermost sheet is fed in the sheet feeding direction by the rotation of the sheet feeding roller, but the sheet is locked to the separation claw 6 while receiving the sheet feeding force of the sheet feeding roller. The sheet is fed one by one so that the separation claw 6 rides up.
[0005]
[Problems to be solved by the invention]
In the conventional paper cassette configured as described above, when saving space (reducing the installation area), the paper is loaded in the paper cassette in a flat state, limited by the size of the paper to be loaded (paper size). Under such conditions, it was difficult to reduce the installation area to be less than the maximum stackable paper size in the paper feed cassette.
[0006]
Therefore, as in the paper feeding cassette described in Japanese Patent Laid-Open No. 5-201553, the tip portion of the paper feeding cassette is curved to reduce the projected area with respect to the installation portion of the paper feeding cassette, thereby saving space. It has been proposed to do.
[0007]
However, in the configuration of the paper feed cassette described in Japanese Patent Application Laid-Open No. 5-201553, the shape of the paper feed cassette itself is different from the conventional general paper feed cassette, and the apparatus side is matched with the shape of the paper feed cassette. There are problems in actual implementation, such as the need to change the mechanism of each part in the cassette installation part.
[0008]
The present invention solves the above-mentioned conventional problems, is simple in configuration, and does not require a change in the installed apparatus side, and stacks and stores sheets in a curved state, not in a flat state, An object of the present invention is to provide a paper feed cassette that can be miniaturized.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is installed in an image forming apparatus , stacks and stores sheets for image formation, and is pivotally supported by a support shaft so that the sheet can be rotated. In the paper feed cassette having a bottom plate that rises from the paper feed position to the paper feed standby position, a projection member that protrudes from the bottom surface portion to bend the substantially central portion of the paper upward is provided on the paper stacking surface, and the projection member is disposed on the bottom plate. The projecting member is installed at a position downstream of the support shaft in the paper feeding direction, the bottom plate is rotatable to avoid the installation position of the projecting member, and the bottom plate is raised to the paper feed standby position. Is located below the bottom plate and does not contact the paper, and has a layout configuration that does not curve the paper , and this configuration curves so that the substantially center of the placed paper is raised, For lifted parts only It is possible to shorten the length of the projection surface, and it is possible to reduce the cassette paper placed space, it is possible to miniaturize the entire paper feed cassette. In addition, it is possible to prevent the installation of the protruding member from adversely affecting the paper feeding in the greasing cassette having the bottom plate. Further, by preventing the sheet from being bent during sheet feeding, it is possible to prevent the sheet feeding characteristic from being deteriorated.
[0010]
According to a second aspect of the present invention, in the paper feed cassette according to the first aspect, the protruding member is provided so as to be detachable. With this configuration, only when the maximum size of paper in the paper feed cassette is stored. By using the protruding member, it can be used.
[0011]
According to a third aspect of the present invention, in the paper feed cassette according to the second aspect, a storage unit for storing the removed protruding member is provided. With this configuration, the protruding member is stored in the cassette when not in use. It is possible to prevent it from being lost.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings. In the following description, the members described in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0015]
FIG. 1 is a plan view showing a configuration of a paper feed cassette for explaining an embodiment of the present invention, FIG. 2 is a cross-sectional view of the paper feed cassette of FIG. 1, and this embodiment is shown in FIGS. The difference from the conventional example is a configuration in which a protruding member 10 protrudes from the sheet placement surface 1 a at the approximate center in the movable region of the end fence 2 and the side fence 3 in the cassette frame 1.
[0016]
As shown in FIG. 2, when the paper P is set on the paper placement surface 1 a, the paper P is bent and stacked upward by an amount corresponding to the protruding amount at the installation portion of the protruding member 10. Therefore, the length in the paper feeding direction on the projection surface of the paper P is shortened by the amount the paper P is lifted upward. The cassette frame 1 can be reduced in size by this shortening, and it is possible to reduce the cassette installation space on the apparatus main body side where the main paper feed cassette is installed.
[0017]
Further, as in the present embodiment, the rear end portion and the side portion of the sheet are directly regulated by the elastic body provided on the inner wall or the inner wall of the cassette frame 1 without installing the end fence 2 and the side fence 3. The same effect can be obtained by providing the protruding member 10 in the paper feeding cassette.
[0018]
Note that the curving of the paper P as described above has an adverse effect on the separation paper feeding characteristics (separation paper feeding by the separation claw 6 in this example), and the cassette frame 1 is curved by an amount that is further curved upward. It becomes necessary to increase the height or to regulate the sheet stacking height. In order to eliminate such a problem, it is conceivable to install the protruding member 10 only when using the maximum size paper that affects the size of the paper feed cassette. It is good to set it as the structure which can be attached to the bottom face of the frame 1 so that attachment or detachment is possible.
[0019]
For example, as shown in FIG. 3, a locking projection 10 a is provided at the lower part of the protruding member 10, and the locking projection 10 a can be attached to and detached from the engagement hole 11 formed on the bottom surface of the cassette frame 1. When the maximum size paper is used, the protruding member 10 is installed by fitting the locking projection 10a into the engagement hole 11, and when the paper having a size smaller than the maximum storage size is used, the protruding member 10 is provided. Try to remove it.
[0020]
Further, when the protruding member 10 is made detachable, it is desirable to install the protruding member storage part 12 in a part of the cassette frame 1 as shown in FIG. 4 in order to prevent the removed protruding member 10 from being lost. In the example shown in FIG. 4, the protruding member storage unit 12 is formed by forming a concave portion in a handle 13 portion used for inserting and removing the paper feed cassette. The projecting member storage unit 12 may be installed at any site as long as it does not affect the paper stacking in the paper feed cassette.
[0021]
Further, as shown in FIGS. 5 and 6, the installation relationship between the bottom plate 4 and the protruding member 10 is such that the installation position of the protruding member 10 is located downstream of the support shaft 5 of the bottom plate 4 in the sheet feeding direction. The bottom plate 4 can be moved up and down while avoiding contact with the sheet P, and the protruding member 10 does not come into contact with the paper P at the position where the bottom plate 4 is raised to the paper feed standby position (the position indicated by the solid line in FIG. 6). Thus, as shown by a two-dot chain line in FIG. 6, when the paper P is set in the paper feed cassette (the bottom plate 4 is locked at the lower position), the set paper P is curved and stacked. In addition, when the sheet is fed, the sheet P and the protruding member 10 are not in contact with each other even when the bottom plate 4 is raised in the sheet feeding cassette.
[0022]
5 and 6, when the bottom plate 4 is raised, the sheet feeding direction side of the bottom plate 4 rises and becomes inclined rather than when the bottom plate 4 is in the lower locked position. The distance from the (feeding direction downstream side) to the rear end of the sheet (end fence 2 side) extends. Therefore, when the bottom plate 4 is raised, the sheet P is stacked without being bent, and the sheet P is stacked without being bent. Therefore, there is no possibility that the sheet feeding performance is deteriorated. it can.
[0023]
【The invention's effect】
As described above, according to the paper feed cassette of the present invention, the length of the projection surface of the paper is increased by the lifted amount by a simple configuration in which the substantially center of the placed paper is curved so as to be lifted by the protruding member. Since it can be shortened, the cassette paper placement space can be reduced, the entire paper feed cassette can be reduced in size, and the mechanism on the main body side where the paper feed cassette is mounted is changed. Therefore, it is possible to reduce the cassette installation space on the apparatus main body side. In addition, the installation of the projecting member does not adversely affect the paper feeding in the greasing cassette having the bottom plate, and the paper feeding characteristics are not deteriorated by preventing the paper from being bent during the paper feeding.
[Brief description of the drawings]
FIG. 1 is a plan view showing the configuration of a paper feed cassette for explaining an embodiment of the present invention. FIG. 2 is a cross-sectional view of the paper feed cassette of the present embodiment shown in FIG. Explanatory drawing which shows the attachment / detachment mechanism of a protrusion member [FIG. 4] The top view which shows the protrusion member storage part in this embodiment [FIG. 5] The top view which shows an example of arrangement | positioning relationship between the baseplate and protrusion member in this embodiment [FIG. FIG. 7 is a cross-sectional view showing an example of the positional relationship between the bottom plate and the projecting member in the embodiment shown in FIG. 5. FIG. 7 is a plan view showing an example of a conventional paper feed cassette. Cross-sectional view of [Signs]
DESCRIPTION OF SYMBOLS 1 Cassette frame 1a Paper mounting surface 2 End fence 3 Side fence 4 Bottom plate 5 Support shaft 6 Separation claw 10 Projection member 10a Locking projection 11 Engagement hole 12 Projection member storage part 13 Handle

Claims (3)

A paper feed cassette that is installed in an image forming apparatus and has a bottom plate that stacks and stores paper for image formation and is pivotally supported by a support shaft so as to raise the paper from a bottom surface to a paper feed standby position. In
The paper stacking surface is provided with a projecting member that projects from the bottom surface part and curves the substantially central portion of the paper upward, and the projecting member is installed downstream of the support shaft of the bottom plate in the paper feeding direction. In a position where the projecting member can be rotated avoiding the installation position and the bottom plate is raised to the paper feed standby position, the projecting member is positioned below the bottom plate so as not to contact the paper. A paper feed cassette characterized in that it is arranged so as not to bend .   The paper feed cassette according to claim 1, wherein the protruding member is detachably provided.   The paper feed cassette according to claim 2, further comprising a storage unit for storing the removed protruding member.

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