JP2004149274A - Sheet feeder, image forming device, and image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of stably supporting a sheet support means without using an expensive high strength material or a wire and placing thereon a large amount of sheets at a low cost. <P>SOLUTION: In the typical configuration of these sheet feeder, image forming device, and image reading device, the sheet feeder A comprises an openable tray 202 for placing the sheets thereon, a sheet feed roller 201 feeding out the sheets, and a separation roller 210 separating the sheets. The sheet feeder also comprises a swingably supported blind cover 203 disposed generally under the tray 202, and the blind cover 203 is engaged with the tray 202 when the tray 202 is opened to restrict the tilt angle of the tray 202. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding apparatus, an image forming apparatus such as a copier and a printer including the same, and an image reading apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, image forming apparatuses such as copiers and printers are provided with a sheet feeding apparatus for manually setting sheets so as to feed various types of sheets and supplying the sheets to an image processing unit such as an image forming unit. Some are being done. This is a so-called multi-sheet feeding device, which has an openable and closable tray, sets a sheet bundle to be supplied on the tray by hand, and automatically supplies sheets to the image processing unit one by one. Things. This multi-sheet feeding apparatus (hereinafter referred to as a sheet feeding apparatus) is generally widely used in image forming apparatuses such as copying machines and printers and image reading apparatuses in order to reduce the design and the installation area of the apparatus. . FIG. 5 is a sectional view of a tray of a conventional sheet feeding apparatus. FIG. 5A is a cross-sectional view illustrating a state where a tray is accommodated in the apparatus main body, and FIG. 5B is a cross-sectional view illustrating a state where the tray is opened outside the apparatus main body.
[0003]
As shown in FIG. 5A, a sheet feeding roller 101 for feeding a sheet is provided on the apparatus main body so as to rotate by receiving driving. The tray 102 that supports the sheet bundle to be manually inserted is rotatably supported by the sheet feeding device about the rotation shaft 102a. An intermediate plate 106 for pressing the sheet to the sheet feeding roller 101 is attached to the tray 102 in a swingable manner. Below the middle plate 106, a pressing plate 107 and a compression spring 108 for generating a pressing force on the middle plate 106 are provided. Further, a stopper 104 for determining a tray angle is disposed below the tray 102 on the apparatus body side.
[0004]
As shown in FIG. 5B, when the tray 102 is opened, the tray 102 and the stopper 104 are engaged, and the angle of the tray 102 is determined. Further, in conjunction with the rotation of the tray 102, the blind cover 103 urged by a torsion spring (not shown) also rotates along the outer surface of the tray 102 about the rotation shaft 103a.
[0005]
In order for the leading edge of the sheets stacked on the tray 102 to abut on the sheet feeding roller 101, the lower portion of the tray 102 (apparatus main body side) is extended, or the rotating shaft 102a is set at the center of rotation of the sheet feeding roller 101. We need to get closer.
[0006]
Here, since the sheet feeding roller 101 is a consumable part, it is necessary to improve exchangeability by a service person or a user. For this reason, the rotation shaft 102a of the tray must be disposed at a position slightly distant from the rotation center of the sheet feeding roller 101 in consideration of the workability of roller replacement.
[0007]
Therefore, in order for the sheet to contact the sheet feeding roller 101, the lower portion of the tray 102 must be extended. At this time, since the rotation shaft 102a of the tray 102 is inside the apparatus main body, the tray 102 itself bites into the apparatus main body. That is, it is necessary to secure a space inside the apparatus main body by the amount of the tray 102 to enter.
[0008]
Here, in order to secure a space corresponding to the amount of entry of the tray 102, a hole is opened in the exterior of the apparatus main body when the tray 102 is closed. Therefore, a multi-sheet feeding apparatus having a normally openable / closable tray is generally provided with a rotary blind cover to cover a space corresponding to the amount of the tray 102 to enter.
[0009]
However, since the distance between the rotation shaft 102a (fulcrum) of the tray 102 and the apparatus body end 102b (working point) of the tray 102 is not sufficient, a large amount of sheets are stacked and the apparatus body end 102b contacts the stopper 104. When the overload is applied, a large force is applied to the rotating shaft 102a of the tray 102, and the rotating shaft 102a may be damaged, and the entire sheet feeding apparatus may not be completely replaced.
[0010]
On the other hand, it is conceivable to secure the strength by enlarging the rotating shaft 102a. However, it is difficult to secure the strength of the rotating shaft 102a because the distance L1 between the rotating shaft 102a and the engaging portion of the stopper 104 cannot be made large.
[0011]
For this reason, conventionally, the sheet stacking capacity of the sheet feeding device is limited, the material of the tray itself (rotary shaft 102a) is reinforced, or the tray is supported by a wire like a suspension bridge.
[0012]
[Problems to be solved by the invention]
However, the above-described conventional sheet feeding device, image forming apparatus, and image reading device have a low degree of freedom in the sheet stacking amount when the sheet stacking amount is limited, and cannot meet user demands. . Further, when the material of the tray itself is reinforced or the wire is supported like a suspension bridge, there is a problem that the cost of the apparatus increases.
[0013]
Therefore, an object of the present invention is to provide a sheet feeding device capable of stably supporting a sheet supporting means without using expensive high-strength materials or wires, and capable of stacking large-capacity sheets at low cost. And
[0014]
[Means for Solving the Problems]
In order to solve the above problems, a typical configuration of a sheet feeding apparatus, an image forming apparatus, and an image reading apparatus according to the present invention includes a sheet supporting unit that is provided in an apparatus main body to be openable and closable and supports a sheet; In a sheet feeding apparatus comprising: a sheet feeding unit for feeding a sheet supported by a supporting unit; and a separating unit for separating sheets fed by the sheet feeding unit into one sheet. A locking means disposed below the means and rotatably supported by the apparatus main body, wherein the locking means engages with the sheet supporting means in a state where the sheet supporting means is opened; It is characterized in that the inclination angle of the sheet supporting means is regulated.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a sheet feeding device, an image forming device, and an image reading device according to the present invention will be described with reference to the drawings. 1 is a cross-sectional view of the image forming apparatus according to the present embodiment, FIG. 2 is a schematic cross-sectional view of a sheet support unit, FIG. 3 is a perspective view of the sheet support unit and a locking unit, and FIG. FIG.
[0016]
As shown in FIG. 1, a copying machine main body 1, which is an example of an image forming apparatus, has a document table 2 made of a transparent glass plate fixedly provided at an upper portion thereof. A document O placed on the document table 2 with the image side facing down is pressed against the document table 2 by a document pressure plate 3 fixed to the document table 2. A lamp 4 for illuminating the original O is provided below the original table 2, and a light image reflected by the lamp 4 illuminating the original O is reflected by an optical system including reflecting mirrors 5 to 10 and an imaging lens 11. It is guided to the photosensitive drum 12 of the image forming section B. Note that the lamp 4 and the reflection mirrors 4 to 7 move at a predetermined speed in the direction of arrow a to scan the original O.
[0017]
In the image forming section B, which is an image forming unit, the photosensitive drum 12 is uniformly charged by a charger 13 and irradiated with a light image of the document O by an optical system to form an electrostatic latent image. The electrostatic latent image formed on the surface of the photosensitive drum 12 is developed by the developing device 14 to form a toner image. The toner image developed on the surface of the photosensitive drum 12 is transferred by the transfer charger 19 to the sheet S fed from the multi-sheet feeding device A or the sheet feeding device C having a sheet feeding cassette. The sheet S to which the toner image has been transferred is separated from the photosensitive drum 12 by the separation charger 20. After the transfer of the toner image, the toner remaining on the photosensitive drum 12 is removed by the cleaner 26, and the photosensitive drum 12 prepares for the next image formation.
[0018]
The sheet S to which the toner image has been transferred in the image forming unit B is conveyed to the fixing unit 22 by the conveying unit 21 provided on the downstream side of the image forming unit B, and the toner transferred onto the sheet S by the fixing unit 22. The image is fixed as a permanent image. Then, the sheet S on which the toner image has been fixed by the fixing device 22 is discharged by a discharge roller 24 to a discharge tray 25 provided outside the copying machine main body 1.
[0019]
Next, the multi-sheet feeding device (hereinafter, referred to as a sheet feeding device) A will be described. FIG. 2A is a cross-sectional view illustrating a state where the tray 202 is accommodated in the apparatus main body, and FIG. 2B is a cross-sectional view illustrating a state where the tray 202 is opened outside the apparatus main body.
[0020]
As shown in FIG. 2A, the sheet feeding apparatus A includes a sheet feeding roller 201, a multi-tray 202 (hereinafter, referred to as a tray), a blind cover 203, a torsion spring 205, a middle plate 206, It comprises a pressure plate 207, a compression spring 208, a guide 209, and a separation roller 210.
[0021]
The sheet feeding roller 201 is a sheet feeding unit that conveys the sheet S, and is provided on a tray 202 so as to be rotated by being driven by a motor or the like.
[0022]
The tray 202 is a sheet supporting unit on which the sheet S is placed, and is attached to the sheet feeding device so as to be rotatable around a rotation shaft 202a. An intermediate plate 206 is attached to the tray 202 so as to be rotatable with respect to the tray 202 so that the sheet S comes into contact with the sheet feeding roller 201 at the timing of feeding the sheet. Below the middle plate 206, a pressing plate 207 for pressing the middle plate 206 against the sheet feeding roller 201 and a compression spring 208 for generating a pressing force are arranged in the apparatus main body.
[0023]
The blind cover 203 is urged by the torsion spring 205 in a direction (counterclockwise direction in the drawing) in contact with the tray 202. When the tray 202 is closed, the exterior lines of the tray 202 and the blind cover 203 are the same. They are arranged so that they become planes.
[0024]
A guide 209 is a sheet guide that guides the sheet S from the middle plate 206 to the sheet feeding roller 201 and further to the image forming unit B downstream thereof. The separation roller 210 is a separation unit that separates a sheet, is provided opposite to the sheet feeding roller 201, is connected to a torque limiter (not shown), and is driven to rotate in a direction opposite to the sheet conveyance direction.
[0025]
As shown in FIG. 2B, when the tray 202 is rotated and opened in the direction of the arrow in the figure, the blind cover 203 is brought into contact with the outer surface of the tray 102 by the torsion spring 205 in conjunction with the rotation of the tray 202. In this state, it turns in the direction of the arrow in the figure. Then, the tray 202 and the blind cover 203 are engaged with the engaging portions 202b and 203b, respectively, and the tray 202 is fixed at a predetermined angle. Then, the pressing plate 207 and the middle plate 206 come into contact with each other, and the pressing plate 207 applies a pressing force to the middle plate 206.
[0026]
Further, as shown in FIG. 3, a groove 203c, which is a concave portion, is provided on the blind cover 203. In the groove 203c, the entrance of the groove is widened by chamfering. A rib 202c, which is a fitting means, is provided on the tray 202, and the rib 202c and the groove 203c are engaged with each other to position the tray 202 in the sheet width direction as shown by a dashed line. By providing the groove 203c on the blind cover 203 and positioning the tray 202 and the blind cover 203 in this manner, it is possible to prevent printing deviation in the sheet width direction due to play of the tray.
[0027]
Note that the groove 203c is not limited to this mode, and the position of the tray 202 and the blind cover 203 in the sheet width direction can be changed by a boss and a hole, another concave portion such as two ribs, a convex portion, or the like. You may decide.
[0028]
Further, as shown in FIG. 4, when the tray 202 and the blind cover 203 are engaged with the engagement portions 202b and 203b, respectively, the force F perpendicular to the slope of the engagement portion 203b is applied to the blind cover 203 from the tray 202. Acts. When this force F is decomposed into a force F1 from the point of application of the force F to the rotation axis 203a and a force F2 in a direction orthogonal to the force F1, a vector diagram shown in FIG. 4 is obtained. In order for the blind cover 203 to support the tray 202 at a predetermined angle against the rotational moment generated by the weight of the tray 202 and the middle plate 206, it is necessary to receive a force F2 in the direction opposite to the rotation direction of the tray 202. To satisfy this, the angle θ between the direction of the slope of the engagement portion 203b and the line connecting the rotation axis 203a from the point of action of the force F must be greater than 90 ° (180 °>θ> 90 °). Will be needed. That is, the direction of the slope of the engaging portion 203b needs to be set so that when a force is applied to the slope from the tray 202, the component force is opposite to the rotation direction of the tray 202.
[0029]
As described above, the tray 202 is configured to engage with the blind cover 203 in an open state to regulate the inclination angle of the tray 202. As a result, the distance L2 between the rotating shafts 202a of the tray 202 and the engaging portion 203b of the 203 can be increased (L2> L1), and even if a large amount of sheets S are stacked on the tray 202 and overloaded, the rotating shaft The load on 202a is reduced. For this reason, breakage of the rotating shaft 202a can be prevented, and the sheet S can be stably supported. Further, by increasing the distance L2 between the rotation shafts 202a and 203 of the tray 202 to the engagement portion 203b (L2> L1), the degree of freedom in designing the rotation shaft 202a is increased, and the strength is increased by increasing the diameter. The rotation shaft 202a can be prevented from being damaged.
[0030]
In addition, by providing the groove 203c in the blind cover 203 and positioning the tray 202 and the blind cover 203, it is possible to prevent printing deviation in the sheet width direction due to play of the tray 202.
[0031]
In the present embodiment, the copying machine main body 1 which is an image forming apparatus including the sheet feeding device A has been described. However, the present invention is not limited to this. The present invention can also be applied to an image forming apparatus or an image reading apparatus including an image reading unit that reads an image of a sheet sent from the sheet feeding apparatus A.
[0032]
【The invention's effect】
As described above, the locking means engages with the sheet supporting means in a state where the sheet supporting means is opened, and regulates the inclination angle of the sheet supporting means. This makes it possible to increase the distance between the rotation center of the sheet supporting means and the engaging portion of the locking means (the distance between the fulcrum of the sheet supporting means and the point of action), and to load a large amount of sheets on the sheet supporting means. Even if an overload is applied, the center of rotation can be prevented from being damaged, and the seat can be stably supported. Further, since the distance between the rotation center of the seat supporting means and the engaging portion of the locking means (the distance between the fulcrum of the seat supporting means and the point of action) can be increased, the degree of freedom in designing the rotation center increases. By increasing the diameter of the shaft, the strength can be increased, and damage to the center of rotation can be prevented. Therefore, the sheet supporting means can be stably supported without using expensive high-strength materials or wires, and large-capacity sheets can be stacked at low cost.
[Brief description of the drawings]
FIG. 1 is a sectional view of an image forming apparatus according to an embodiment.
FIG. 2 is a schematic sectional view of a sheet supporting means.
FIG. 3 is a perspective view of a sheet supporting means and a locking means.
FIG. 4 is a detailed view of a seat supporting means and a locking means.
FIG. 5 is a schematic sectional view of a conventional sheet supporting means.
[Explanation of symbols]
A: Sheet feeding device B: Image forming unit L1: Distance O: Document S: Sheet 1: Copying machine body 2: Document table 3: Document pressing plate 4: Lamp 5: Reflecting mirror 10: Reflecting mirror 11: Image forming lens Reference Signs List 12 photosensitive drum 14 developing device 19 transfer charger 20 separation charger 21 transport unit 22 fixing device 24 discharge roller 25 discharge tray 201 sheet feeding roller 202 tray 202a rotating shaft 202b Joint portion 202c Rib 203 Blind cover 203b Engagement portion 203c Groove 206 Middle plate 207 Press plate 208 Compression spring 209 Guide 210 Separation roller

Claims (6)

A sheet supporting means which is provided to be capable of being opened and closed on the apparatus main body and supports the sheet, a sheet feeding means for feeding out the sheet supported by the sheet supporting means, and a sheet fed by the sheet feeding means, one by one. Separating means for separating, and a sheet feeding device comprising:
A locking means disposed below the sheet supporting means and rotatably supported by the apparatus main body,
The sheet feeding device according to claim 1, wherein the locking means engages with the sheet supporting means in a state where the sheet supporting means is opened, and regulates an inclination angle of the sheet supporting means. The locking means has an engaging portion having a slope that comes into contact with the engaging portion of the sheet support means, and forms a line connecting the direction of the slope of the engaging portion and the pivot point of the locking means. 2. The sheet feeding device according to claim 1, wherein the angle [theta] is set to be larger than 90 [deg.]. The sheet feeding device according to claim 1, wherein the locking unit is a blind cover for covering a lower side of the sheet supporting unit. The locking means includes at least one or more convex portions or concave portions at a position substantially perpendicular to the sheet conveying direction,
The sheet feeding device according to any one of claims 1 to 3, wherein the sheet support unit includes a fitting unit that fits into the protrusion or the recess. A sheet feeding device according to any one of claims 1 to 4,
Image forming means for forming an image on the sheet sent from the sheet feeding device,
An image forming apparatus comprising: A sheet feeding device according to any one of claims 1 to 4,
Image reading means for reading the image of the sheet sent from the sheet feeding device,
An image reading apparatus comprising:

Images