JP2004189388A - Paper sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet feeder for preventing any paper sheet feed operation when paper sheets are excessively stacked with a simple configuration. <P>SOLUTION: The paper sheet feeder comprises a paper sheet feed tray 12 attachable/detachable to/from an image forming apparatus body 9, a tray cover 14 attachably/detachably fitted to the paper sheet feed tray 12, a cover sensor 20 to detect presence/absence of the tray cover 14, and a projection part 18 provided on an inner surface of the tray cover 14 so as to raise the tray cover 14 by the touch with an upper surface of a paper sheet P if the paper sheets P of the capacity exceeding the maximum value are stacked and stored in the paper sheet feed tray 12 when the tray cover 14 is fitted to the paper sheet feed tray 12. The cover sensor 20 detects absence of the cover when the tray cover 14 is raised, and performs no paper feed operation when absence is detected. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding device of an image forming apparatus.
[0002]
[Prior art]
[Patent Document 1]
JP-A-6-199428 [Patent Document 2]
JP-A-9-77304
Conventionally, in order to prevent overloading of sheets on a sheet feed tray of an image forming apparatus, in Japanese Patent Application Laid-Open No. H11-163, the amount of rotation of a call roller is determined by using a configuration in which a call roller rotates in a swinging manner so as to come into contact with and separate from the upper surface of a sheet. Patent Document 2 discloses a technique for determining whether or not a sheet stacking amount is a specified amount by detecting the number of sheets, and using a combination of a sheet feeding tray elevating mechanism and a sheet upper limit detecting unit. Measure the time required to raise the paper feed tray to the position where the upper end of the paper stacked on it is detected by the upper limit detection means, and compare this measured time with the specified time to determine whether the paper is overloaded. A technique for detecting whether or not it has been disclosed.
[0004]
[Problems to be solved by the invention]
However, a paper feeder that adopts a configuration such as the above-described swinging call roller or a paper feed tray that moves up and down separately from the drive of the image forming apparatus main body is generally a high-priced, high-speed, large-sized device. When mounted on a low-priced, low-speed, small-sized device, the cost is increased, the size is increased, and the control is complicated, which is not preferable.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet feeding device having a function of preventing overloading of sheets with a simple and inexpensive configuration.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a sheet feeding device according to a first aspect of the present invention includes a sheet feeding tray detachably attached to an image forming apparatus main body, a tray cover detachably attached to the sheet feeding tray, and the presence or absence of the tray cover. And a tray detecting means for detecting when the tray cover is mounted on the paper feed tray and the paper tray is in contact with the upper surface of the paper when paper larger than the maximum capacity is loaded and stored in the paper feed tray. A protrusion provided on the inner surface of the tray cover so as to lift the cover, wherein the cover detecting means detects the absence of the cover when the tray cover is in a floating state, and does not perform the sheet feeding operation at the time of this detection. It is like that.
[0007]
According to a second aspect of the present invention, there is provided a paper feeding device, wherein the paper feeding tray is detachably mounted on the image forming apparatus main body, a tray cover is detachably mounted on the paper feeding tray, and the presence or absence of paper on the paper feeding tray. A sheet detecting means for detecting, and when the tray cover is mounted on the paper feed tray, the paper cover is contacted with the upper surface of the paper when the paper tray is loaded with paper exceeding a maximum capacity. A projection provided on the inner surface of the tray cover so that the tray cover is lifted up, and an interlocking member interlocked to transmit the state in which the tray cover is lifted to the paper detection unit. Also serves as a cover detecting means for detecting the presence / absence, and does not perform the paper feeding operation when the paper detecting means detects at least one of the absence of the paper and the absence of the cover. Those were Unishi.
[0008]
【The invention's effect】
According to the sheet feeding device of the first invention, it is very simple and inexpensive to detect whether or not the tray cover rises when the tray cover provided with the protrusion on the inner surface is attached to the sheet feeding tray by the cover detecting means. With this configuration, it is possible to prevent the paper feeding operation from being performed at the time of paper overloading, thereby avoiding a problem such as damage to the paper feed-related components due to the paper feeding operation in the paper overloading state.
[0009]
Further, according to the second aspect of the present invention, it is not necessary to separately provide a detecting means for detecting the cover by using the conventionally used paper detecting means also as the cover detecting means.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall schematic configuration diagram of an image forming apparatus 1 including a sheet feeding device 10 according to an embodiment of the first invention. In the image forming apparatus 1, the sheets P stacked and stored in the sheet feeding device 10 are fed one by one from the top by the sheet feeding roller 2, and the fed sheet P is conveyed upward by the conveying roller pair 3 and developed. The toner image is transferred onto the paper P when passing between the device 4 and the transfer roller 5, and the transferred toner image is fixed on the paper P when passing through the nip portion of the fixing roller pair 6, The paper P on which is fixed is discharged onto a paper discharge tray 8 via a paper discharge roller pair 7.
[0011]
The paper feeding device 10 includes a paper feeding tray 12 that is detachable from the image forming apparatus main body 9. Paper P is stacked and stored on the paper feed tray 12. As shown in FIG. 2, for example, a transparent or translucent plastic tray cover 14 is detachably attached to the paper feed tray 12. The tray cover 14 protects the sheets P stacked and accommodated on the sheet feeding tray 12 from dust and foreign matters, and prevents the sheet P of the image forming apparatus main body 9 from being erroneously put into the operating machine. The opening is closed.
[0012]
Although the inside of the paper feeder 10 is secured so that it is not injured even if hands are put in place by jam handling or the like, a tray cover 14 is attached to the paper feed tray 12 to further secure children and the like. If not, the presence or absence of the tray cover 14 is detected by a cover sensor (cover detecting means) 20 provided in the image forming apparatus main body 9 as shown in FIG. For the cover sensor 20, for example, a photo interrupter is preferably used.
[0013]
On the lower surface of the edge of the tray cover 14, a detection plate 16 formed of a rectangular projection is protruded. As shown in FIG. 4A, the detection plate 16 shields the cover sensor 20 when the tray cover 14 is properly mounted on the paper feed tray 12, thereby detecting the presence of the tray cover. The paper feeding operation is permitted.
[0014]
In addition, a projection 18 formed of a rectangular projection is projected from the inner surface of the tray cover 14. In the tray cover 14, the projection 18 is provided slightly forward in the paper feeding direction (the direction of arrow A in FIG. 3), and is provided slightly closer to the detection plate 16 than the center in the width direction orthogonal to the paper feeding direction. ing. The height h of the protrusion 18 is determined according to the maximum sheet stacking capacity of the sheet tray 12.
[0015]
The projection 18 is preferably formed integrally with the tray cover 14, but may be fixed by a method such as adhesion, welding, screwing, or caulking. Further, the projection 18 is not limited to a rectangular protruding piece, and may have any shape, such as a rod, a cone, a prism, a hemisphere, and an arc, as long as it protrudes from the inner surface of the tray cover 14.
[0016]
Referring again to FIG. 1, a paper sensor 22 as a paper detecting unit is disposed below the developing device 4 inside the image forming apparatus main body 9. For the paper sensor 22, for example, a photo interrupter is preferably used.
[0017]
In the vicinity of the paper sensor 22, a substantially fan-shaped light-shielding plate 26 fixed to a rotatable shaft 24 with a predetermined angular relationship and a paper detection rod 28 are arranged to be swingable about the shaft 24. When the paper feed tray 12 is mounted on the image forming apparatus main body 9, the tip of the paper detection rod 28 contacts the upper surface of the paper P stored on the paper feed tray 12, and at this time, the light shielding plate 26 is The light sensor 22 is not shielded from light, so that the paper sensor 22 detects the presence of paper and permits the paper feeding operation. On the other hand, when there is no paper P on the paper feed tray 12 and the tip of the paper detection rod 28 abuts on the bottom of the paper feed tray 12, the light shielding plate 26 shields the paper sensor 22 from light. Is detected and the paper feeding operation is not performed. The above-described configuration for detecting the presence or absence of the sheet P using the sheet sensor 22, the shaft 24, the light shielding plate 26, and the sheet detection rod 28 has been conventionally employed.
[0018]
Next, the operation of the sheet feeding device 10 having the above-described configuration will be described.
As shown in FIG. 4A, when sheets P having a maximum capacity or less are stacked and stored in the sheet feeding tray 12, the tip of the protrusion 18 does not contact the upper surface of the sheet P, and the tray cover 14 Can be properly mounted on the paper feed tray 12. Thus, the detection plate 16 of the tray cover 14 shields the cover sensor 20 to detect the presence of the cover, and the sheet feeding operation is permitted.
[0019]
On the other hand, as shown in FIG. 4B, when the paper P exceeding the maximum capacity is loaded and stored in the paper feed tray 12, the tip of the projection 18 contacts the upper surface of the paper P, and the tray cover rises. And the paper tray 12 cannot be properly mounted. At this time, the detection plate 16 of the tray cover 14 does not shield the cover sensor 20 from light, and the absence of the cover is detected from this, so that the sheet feeding operation is controlled not to be performed.
[0020]
As described above, according to the sheet feeding device 10 of the present embodiment, the cover sensor 20 detects whether or not the tray cover 14 rises when the tray cover 14 provided with the protrusion 18 on the inner surface is attached to the sheet feeding tray 12. With a very simple and inexpensive configuration, it is possible to prevent the paper feed operation from being performed when paper is overloaded, thereby damaging the paper feed-related components such as the paper feed roller 2 due to the paper feed operation in the paper overloaded state. Such a problem can be avoided.
[0021]
Next, a sheet feeding device 30 according to an embodiment of the second invention will be described with reference to FIGS. The same components as those of the above-described paper feeding device 10 are denoted by the same reference numerals, and detailed description thereof will be omitted.
The paper feeder 30 differs from the paper feeder 10 in that the cover sensor 20 is omitted and the paper sensor 22 is also used to detect the presence or absence of the tray cover 14.
[0022]
As shown in FIG. 5, in the paper feeding device 30, one end 33 of the L-shaped lever 32 is located at a position where the cover sensor 20 is arranged in the paper feeding device 10. The other end of the L-shaped lever 32 is fixed to one end of a shaft 34 rotatably arranged concentrically with the shaft 24 of the paper detecting mechanism. The L-shaped lever 32 is urged in the direction of arrow B by a torsion spring 38 attached to the one end of the shaft 34, and a normal stop position is determined by a stopper (not shown). A light-shielding plate 36 is fixed to the other end of the shaft 34 with a predetermined angular relationship with respect to the L-shaped lever 32. The light shielding plate 36 is positioned so as to be able to shield the paper sensor 22 along with the light shielding plate 26 of the paper detecting mechanism.
[0023]
As described above, the interlocking member constituted by the L-shaped lever 32, the shaft 34, and the light shielding plate 36 serves as the tray cover 14 which is generated when the paper P exceeding the maximum capacity is loaded and stored in the paper feed tray 12 as described above. Are linked so as to notify the paper sensor 22 of the raised state to the paper sensor 22 as having no cover.
[0024]
Specifically, when the sheet tray 12 with the tray cover 14 attached thereto is mounted on the image forming apparatus main body 9, and the sheet tray 12 is loaded with sheets The tray cover 14 having the L-shaped lever 32 is properly mounted on the paper feed tray 12. At this time, the tip of the detection plate 16 of the tray cover 14 contacts the tip 33 of the L-shaped lever 32, and Is pushed in to rotate in the direction of arrow C. Accordingly, the light shielding plate 36 is rotated upward through the shaft 34 to be at a position where the light shielding of the paper sensor 22 is released. At this time, if the light shielding plate 26 of the paper detecting mechanism has also released the light shielding, the paper sensor 22 detects the presence of the paper and the presence of the cover, and permits the paper feeding operation. Even if the light shielding plate 36 releases the light shielding of the paper sensor 22, if the other light shielding plate 26 is in the light shielding state, the paper sensor 22 detects that there is no paper, so that the paper feeding operation is not performed. .
[0025]
On the other hand, when the paper feed tray 12 with the tray cover 14 attached thereto is mounted on the image forming apparatus main body 9 and the paper P exceeding the maximum capacity is loaded and stored in the paper feed tray 12, When the tray cover 14 comes into contact with the upper surface of the sheet P, the tray cover 14 is not properly attached to the sheet feeding tray 12 and floats up (see FIG. 4B). The L-shaped lever 32 may not be in contact with the L-shaped lever 32, or the amount of the L-shaped lever 32 pushed by the detection plate 16 may be insufficient. As a result, the light-shielding plate 36 remains in a state where the paper sensor 22 is shielded from light, and even when the other light-shielding plate 26 releases the light-shielding (that is, when there is a paper), the paper sensor 22 is the same as when it detects that there is no paper. No paper feeding operation is performed because the state is reached.
[0026]
As described above, according to the paper feeding device 30, since the conventionally used paper sensor 22 is also used as the cover sensor, there is no need to separately provide a detecting unit for detecting the cover.
[0027]
Note that when the paper sensor is also used as a cover sensor, and the paper sensor can identify each detection of no paper or no cover, the paper feeding is performed when at least one of paper absence and no cover is detected. No action is taken.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram of an image forming apparatus including a sheet feeding device.
FIG. 2 is a perspective view showing a state in which a tray cover is attached to a sheet feeding tray of the sheet feeding device according to the first invention.
FIG. 3 is a perspective view showing a state in which a tray cover is removed from a sheet feeding tray.
4A is a diagram illustrating a state in which the tray cover is properly mounted on a sheet feeding tray, and FIG. 4B is a diagram illustrating a state in which the tray cover is lifted from the sheet feeding tray due to overloading of sheets.
FIG. 5 is a perspective view showing a sheet feeding device according to a second invention.
FIG. 6 is a perspective view of a sheet detection mechanism and a cover detection mechanism.
FIG. 7 is a plan view of a sheet detection mechanism and a cover detection mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10, 30 ... Paper feeder, 12 ... Paper feed tray, 14 ... Tray cover, 16 ... Detection plate, 18 ... Projection part, 20 ... Cover sensor, 22 ... Paper sensor, 24 ... Shaft, 26 .., Light shielding plate, 28, paper detection rod, 32, L-shaped lever, 34, shaft, 36, light shielding plate, 38, torsion spring.

Claims (2)

A sheet feeding tray detachably attached to the image forming apparatus main body, a tray cover detachably attached to the sheet feeding tray, a cover detecting means for detecting the presence or absence of the tray cover, and the tray cover attached to the sheet feeding tray. A projection provided on the inner surface of the tray cover so that the tray cover is lifted by abutting on the upper surface of the paper when the paper that exceeds the maximum capacity is loaded and stored in the paper feed tray when installed; Wherein the cover detecting means detects the absence of the cover when the tray cover is in a floating state, and does not perform the sheet feeding operation at the time of the detection. A sheet tray that can be attached to and detached from the image forming apparatus body, a tray cover that is detachably attached to the sheet tray, sheet detection means for detecting the presence or absence of sheets on the sheet tray, and the tray cover. When papers larger than the maximum capacity are loaded and stored in the paper feed tray when mounted on the paper feed tray, the paper tray is provided on the inner surface of the tray cover so that the tray cover floats by coming into contact with the upper surface of the paper. A projection, and an interlocking member that interlocks to transmit the state in which the tray cover is lifted to the paper detection means, wherein the paper detection means also serves as cover detection means for detecting the presence or absence of the tray cover. A sheet feeding device that does not perform a sheet feeding operation when the sheet detecting unit detects at least one of a sheet absence and a cover absence.

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