JP2004250113A - Sheet size detection mechanism of cassette - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet size detection mechanism placed in a cassette stored in an image forming apparatus so as to be freely inserted/detached into/from the apparatus, simple in structure, with a small setting space and at low cost. <P>SOLUTION: The sheet size detection mechanism comprises a freely movable pressing member pressed against the sheet placed in the cassette, a following member with a tip end in a cassette inserting direction having a projecting part or more swinging by interlocking with the pressing member, a detecting member having a detecting body elastically deformed by allowing the projecting part to abut on the image forming apparatus, and a multiple switch switched by operation of the detecting body. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanism for detecting the size of paper loaded in a cassette that is detachably stored in an image forming apparatus. More specifically, the structure is simple, the installation space can be reduced, and the cost can be reduced. The present invention relates to a paper size detection mechanism.
[0002]
[Prior art]
In an image forming apparatus such as an electrostatic copying machine, a facsimile machine, or a printer, a paper feed cassette capable of appropriately loading various sizes of paper is detachably provided. The image forming apparatus in which the cassette is accommodated can automatically detect the loaded paper size.
[0003]
A typical example of the paper size detection mechanism includes a mechanism having a switch that detects a position of a pressing member that is pressed against an end of the paper and defines the position of the paper when the paper is loaded on the cassette. However, since this mechanism has to be provided with switches as many as the number of paper sheets, there is a problem that the number of parts is increased and a large space is required to provide many switches, and the image forming apparatus is made compact. It is an obstacle in the above.
[0004]
In order to solve this problem, an apparatus has been developed that detects the size of a sheet by reducing the number of switches and combining on / off of the switches (see, for example, Patent Document 1). This improved paper size detection device includes three push switches provided in the image forming apparatus main body and a segment provided with a gear on the periphery, which rotates in conjunction with a pressing member provided in the cassette. A gear, an idle gear that is rotated by the segment gear, and a rack that meshes with the idle gear, moves according to the rotation of the segment gear, and selectively pushes the switch when the cassette is inserted into the image forming apparatus. And a notch member having irregularities to be turned on and off.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-251951 (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, the improved paper size detection apparatus as described above has the following problems to be solved.
[0007]
That is, since gears such as segment gears, idle gears and racks and a plurality of independent (three) switches are used, the mechanism becomes complicated and the cost becomes high.
[0008]
The present invention has been made in view of the above-described facts, and its technical problem is that a size detection mechanism for paper loaded in a cassette that is detachably accommodated in an image forming apparatus can be installed with a simpler mechanism and an installation space. It is possible to reduce the size and to provide at a low cost.
[0009]
[Means for Solving the Problems]
In the present invention, as a mechanism for solving the above technical problem, a mechanism for detecting the size of paper loaded in a cassette that is detachably stored in an image forming apparatus,
The cassette is pressed against the end of the stacked paper and is positioned at a position corresponding to the size of the paper. The cassette is movably provided, and the center of the swing is linked to the movement of the pressing member. And a follow-up member provided so as to freely swing,
The follower member is provided with an arc-shaped portion centered on the swing center at the distal end portion in the insertion direction of the cassette and having one or more convex portions projecting in the radial direction,
The image forming apparatus includes a detection member having a plurality of detection bodies that are elastically deformed in the cassette insertion direction when the convex portions come into contact with the arc-shaped portions, and each of the detection bodies. A cassette paper size detection mechanism is provided, which includes a multiple switch that is switched by the operation of the cassette.
[0010]
And, instead of a plurality of independent switches, one small and inexpensive multiple switch, and a detection member using an elastic body between the cassette and the switch, the mechanism is simplified and a small space is saved. Enables and lower costs.
[0011]
In a preferred embodiment, the multiple switch includes a plurality of automatic return contacts that abut each of the detectors. Each of the detectors is formed in a cantilevered rectangular plate shape.
[0012]
Then, the automatic return type multiple switch is operated by an elastic plate-like member which is deformed by insertion of the cassette.
[0013]
In a preferred embodiment, each of the detectors transmits the operation stroke in the cassette insertion direction by the contact with the convex portion to the contact element in a contracted manner.
[0014]
The detection stroke can be reduced, and a small multiple switch can be used as a switch.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a paper size detection mechanism (hereinafter simply referred to as a paper size detection mechanism) of a cassette configured according to the present invention will be described in more detail with reference to the accompanying drawings illustrating a preferred embodiment.
[0016]
A description will be given with reference to FIG. 1, which is a plan view of the cassette, as seen from the sheet stacking portion on the upper surface side of the cassette. A paper size detection mechanism, generally indicated by numeral 2, has a pressing member 6 that is movably provided in the cassette 4 and is positioned at a position corresponding to the size of the paper pressed against the end of the paper P stacked on the cassette 4. A follow-up member 10 having an arcuate portion 10a at the front end in the cassette insertion direction indicated by an arrow X, which is provided so as to be swingable around a swing center 8 in conjunction with the movement of the member 6; A detection member 12 for detecting contact with the arcuate portion 10a at a position facing the arcuate portion 10a of the cassette 4 inserted in an image forming apparatus main body (not shown) in which the image forming apparatus is removably accommodated. And a multiple switch 14 that is switched by the operation of the detection member 12.
[0017]
The cassette 4 does not constitute a novel feature of the present invention except for the paper size detection mechanism 2, and may be of a known form per se. Therefore, the description other than the paper size detection mechanism 2 is omitted. In the known cassette 4, the selected size paper P is positioned and stacked by a pair of width defining members 16 a and 16 b provided movably and the above-described pressing member 6.
[0018]
A description will be given with reference to FIG. 2, which is an enlarged plan view of the paper size detection mechanism 2 together with FIG. The follower member 10 includes a fan-shaped portion 18 and a follower arm portion 20, and is disposed on the lower surface side of the cassette 4. The follow-up member 10 is attached to the cassette 4 by a shaft member 22 so that the swing center 8 is positioned at a substantial part of the fan of the fan-shaped portion 18 and is swingable. A follower arm portion 20 extends on the opposite side of the swing center 8 of the fan-shaped portion 18.
[0019]
In the arc-shaped portion 10a of the fan-shaped portion 18, a pair of convex portions 18a and 18b protruding in the radial direction are disposed with the concave portion 18c interposed therebetween in the circumferential direction. The circumferential positions of the convex portions 18a, 18b and the concave portion 18c are detected depending on the movement position that varies depending on the paper size of the pressing member 6 of the cassette 4, and the convex portion 18a and / or the convex portion 18b coming into contact with the insertion of the cassette 4. It is set according to the relationship with the member 12 (this contact relationship will be described in detail later).
[0020]
A long hole-shaped guide hole 20 a extending in the radial direction from the swing center 8 is formed at the distal end portion of the follower arm portion 20. A protruding shaft 6a provided on the pressing member 6 is movably fitted in the guide hole 20a. Therefore, as shown in FIG. 1, when the pressing member 6 is moved between the position (A) for defining the small size and the position (E) for defining the large size, depending on the size of the paper P stacked on the cassette 4. Since the projecting shaft 6a of the pressing member 6 and the guide hole 20a of the follower member 10 are fitted, the follower member 10 swings around the swing center 8 as shown by the arrow Y, that is, the position (A ) Swings in the counterclockwise direction when moved from position (E) to the position (E), and conversely when moved in the direction from position (E) to position (A).
[0021]
The detection member 12 will be described with reference to FIGS. 3 to 6 and FIG. 5 and FIG. 6 together with FIG. The detection member 12 is integrally formed in a substantially flat plate shape with a plastic such as polyacetal (POM). In the detection member 12, three detection bodies 12 a, 12 b, and 12 c are formed on a flat plate surface F that is positioned facing the cassette insertion direction X. Each of the detection bodies 12a, 12b, and 12c is formed in a rectangular plate shape that extends vertically, and an upper end portion thereof is integrally supported and connected to the flat plate surface F, arranged in parallel on the same plane, and extends downward in a cantilever shape. ing.
[0022]
Protruding pieces T1, T2, and T3 projecting in the cassette insertion direction X are provided at positions at a distance L1 from the upper ends of the lower ends of the detection bodies 12a, 12b, and 12c. In addition, at a position at a distance L2 from the upper end of approximately half of the distance L1, a convex portion in which the contact of the multiple switch 14 is brought into contact with the back surface of the surface provided with the protruding pieces T1, T2, and T3. T4, T5, and T6 are formed. The arrangement interval of the convex portions T4, T5, and T6 is smaller than the interval between the protruding pieces T1, T2, and T3 in accordance with the interval between the contacts of the multiple switch 14 (for the multiple switch 14). Will be described later).
[0023]
Thus, each of the detection bodies 12a, 12b, and 12c is deformed when any one of the protruding pieces T1, T2, and T3 is pushed and deformed by the projection 18a or the projection 18b of the follow-up member 10 by insertion of the cassette 4. The operation stroke in the cassette insertion direction X, which is the amount, is reduced to about ½ of L2 / L1 and transmitted to the convex portions T4, T5, and T6.
[0024]
The detection member 12 is attached to an image forming apparatus main body (not shown) by a plurality (five) of hook-shaped attachment legs 12d formed integrally.
[0025]
The multiple switch 14 will be described with reference to FIGS. 2 and 4 together with FIG. 7 and mainly with reference to FIG. The multiple switch 14 is an automatic return type on / off switch having three contacts S1, S2 and S3. When one of the contacts S1, S2, and S3 is pressed, the respective switch is turned on, and when the switch is released, the switch is automatically returned to the off position. The contacts S1, S2 and S3 are arranged in a row, and a plurality of hooks are formed on the image forming apparatus main body (not shown) in contact with the convex portions T4, T5 and T6 of the detection member 12. Are attached by mounting legs 14a and positioning pins 14b.
[0026]
When the contact S1 is pressed and turned on, an electrical signal is output from the connector CN-1, and when the contact S2 is pressed, an electrical signal is output from the connector CN-3. When the contact S3 is pressed, an electrical signal is output from the connector CN-4. Is output.
[0027]
7 and 8 together with FIG. 1, the pair of convex portions 18a and 18b of the follow-up member 10 provided in the cassette 4 and the protruding pieces T1 and T2 of the detection member 12 provided in the image forming apparatus main body Regarding the relationship with T3, that is, the relationship between the follower member 10 that is interlocked with the moving position of the pressing member 6 that moves in accordance with the position of the paper loaded in the cassette 4 and the multiple switch 14 that is operated by the detecting member 12. explain. In the description, the positions (A), (B), (B) between the position (A) that is the position when the pressing member 6 is a small size paper and the position (E) that is the position when the pressing member 6 is a large size paper. C), (D) and (E) are performed according to an example configured to define five sizes.
[0028]
Description will be made mainly with reference to FIG. FIG. 8 shows the convex portions 18a and 18b of the follower member 10 and the protruding pieces T1, T2 and T3 of the opposing detection member 12 in a state immediately before contacting in the cassette insertion direction X.
[0029]
In the position (A), an electrical signal is output from [connector CN-1] of the multiple switch 14 by contact. That is, the convex portion 18a is positioned so as to contact the protruding piece T1, and the protruding pieces T2 and T3 are positioned in the concave portion 18c. Therefore, the contact S1 is operated by the contact of the multiple switch 14, and an electrical signal is output from the connector CN-1.
[0030]
In the (B) position, electrical signals are output from [connectors CN-1, CN-3]. That is, the convex portion 18a is positioned so as to contact the protruding pieces T1 and T2, and the protruding piece T3 is positioned in the concave portion 18c. Therefore, the contacts S1 and S2 of the multiple switch 14 are actuated by contact, and electrical signals are output from the connectors CN-1 and CN-3.
[0031]
In the position (C), electrical signals are output from [connectors CN-1, CN-3, CN-4]. That is, the convex portion 18a is positioned so as to abut against the protruding pieces T1, T2, and T3 by insertion. Accordingly, the contacts S1, S2 and S3 of the multiple switch 14 are actuated by the contact, and electrical signals are output from the connectors CN-1, CN-3 and CN-4.
[0032]
At the position (D), an electrical signal is output from [connectors CN-3, CN-4]. That is, the protrusion 18a is positioned so as to abut against the protruding pieces T2 and T3 by insertion, and the protruding piece T1 is positioned at a position deviated from the protrusion 18a. Accordingly, the contacts S2 and S3 of the multiple switch 14 are actuated by contact, and electrical signals are output from the connectors CN-3 and CN-4.
[0033]
At the position (E), an electrical signal is output from [connector CN-4]. That is, the protrusion 18a is positioned so as to contact the protruding piece T3 by insertion, and the protruding pieces T1 and T2 are positioned at a position away from the protruding portion 18a. Therefore, the contact S3 of the multiple switch 14 is actuated by the contact, and an electrical signal is output from the connector CN-4.
[0034]
Although not shown in FIG. 8, in the case of a paper of a size smaller than that at the position (A), the convex portions 18a and the convex portions 18b at the position (A) are further swung clockwise. The protruding piece T3 is positioned in contact with the protruding pieces T1 and T3, and the protruding piece T3 is positioned in the recess 18c. In this case, the contacts S1 and S2 of the multiple switch 14 are actuated by contact, and an electrical signal is output from [connectors CN-1, CN-4].
[0035]
Further, although not shown in FIG. 8, in the case of a paper having a size larger than that in the (E) position, the convex portions 18a and 18b in the (E) position are further swung counterclockwise. It is moved, and it positions so that it may not contact | abut to protrusion piece T1, T2, and T3. In this case, since the contacts S1, S2 and S3 of the multiple switch 14 do not operate, no electrical signal is output from [connectors CN-1, CN-2, CN-3].
[0036]
As described above, different combinations of electrical signals are output from the multiple switch 14 depending on the position of the pressing member 6 depending on the paper size. By inputting the electrical signals from the connectors CN-1, CN-2 and CN-3 of the multiple switch 14 to the control means (not shown) provided in the image forming apparatus, the combination of the electrical signals is read. The paper size is detected.
[0037]
The operation of the paper size detection mechanism 2 as described above will be described.
[0038]
(1) Simple mechanism, small space:
Instead of a plurality of conventional independent switches, one small and inexpensive multiple switch 14 is used, and instead of a conventional segment gear, idle gear, rack, etc., a follower member 10 having no gear is used, Furthermore, since the detection member 12 made of an elastic body is used, the mechanism can be simplified. Also, a small space becomes possible. In particular, since the detection member 12 is provided with the detection bodies 12a, 12b, and 12c made of cantilever plate members, the insertion stroke of the cassette 4 can be read with a smaller detection width, and thus the multiple switch 14 is downsized. be able to.
[0039]
(2) Cost reduction:
The use of the tracking member 10 that does not use a gear and the inexpensive multiple switch 14 that can be reduced in size makes it possible to reduce the cost of the sheet size detection mechanism.
[0040]
As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications or corrections may be made within the scope of the present invention, for example, as follows. It is something that can be done.
[0041]
(1) Follow-up member:
In the present embodiment, the arcuate portion 10a of the follower member 10 is provided with two convex portions 18a and 18b. However, the number of convex portions is one or more depending on the size of the paper to be detected. What is necessary is just to set suitably.
[0042]
(2) Multiple switches:
In the present embodiment, the automatic return type multiple switch 14 is used. However, the contact of the multiple switch is connected to the detection bodies 12a, 12b, 12c of the detection member 12 by an appropriate means, and a simpler automatic switch is used. A non-returnable switch may be used.
[0043]
【The invention's effect】
According to the paper size detection mechanism of the cassette configured according to the present invention, the size detection mechanism of the paper loaded on the cassette that is detachably stored in the image forming apparatus can be simplified and the installation space can be reduced. And at a low cost.
[Brief description of the drawings]
FIG. 1 is a plan view of a cassette provided with a paper size detection mechanism configured according to the present invention as viewed from a paper stacking unit side.
FIG. 2 is an enlarged plan view showing a paper size detection mechanism.
FIG. 3 is a perspective view of a detection member as viewed from an obliquely upper side on the side of a follow-up member.
FIG. 4 is a perspective view of the detection member viewed from an oblique upper side on the switch side together with the multiple switches.
FIG. 5 is a front view of a detection member.
6 is a cross-sectional view taken in the direction of arrows AA in FIG.
FIG. 7 is a perspective view of a multiple switch.
FIG. 8 is an explanatory diagram showing positions (A) to (E) showing the relationship between the convex portion of the arcuate portion of the tracking member and the detection body of the detection member depending on the paper size.
[Explanation of symbols]
2: Paper size detection mechanism 4: Cassette 6: Pushing member 8: Center of swing 10: Tracking member 10a: Arc-shaped portion 12: Detection member 12a: Detection body 12b: Detection body 12c: Detection body 14: Multiple switch 18a : Convex portion 18b: convex portion P: paper X: cassette insertion direction Y: swinging direction

Claims (4)

A mechanism for detecting the size of paper loaded in a cassette detachably stored in an image forming apparatus,
The cassette is pressed against the end of the stacked paper and is positioned at a position corresponding to the size of the paper. The cassette is movably provided, and the center of the swing is linked to the movement of the pressing member. And a follow-up member provided so as to freely swing,
The follower member is provided with an arc-shaped portion centered on the swing center at the distal end portion in the insertion direction of the cassette and having one or more convex portions projecting in the radial direction,
The image forming apparatus includes a detection member having a plurality of detection bodies that are elastically deformed in the cassette insertion direction when the convex portions come into contact with the arc-shaped portions, and each of the detection bodies. A cassette paper size detection mechanism, comprising: a multiple switch that is switched by the operation of the cassette. The cassette paper size detection mechanism according to claim 1, wherein the multiple switch includes a plurality of automatic return contacts that abut against each of the detection bodies. The cassette paper size detection mechanism according to claim 1 or 2, wherein each of the detection bodies is formed in a cantilevered rectangular plate shape. The cassette paper size detection mechanism according to claim 3, wherein each of the detectors reduces and transmits an operation stroke in a cassette insertion direction due to contact with the convex portion to the contact.

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