JP4102956B2 - Document reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an original reading apparatus used in a copying machine, a scanner, or the like, and more particularly to an improvement of an original reading apparatus provided with an original pressing plate that is attached to an original placing plate so as to be freely opened and closed.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, as a document reading apparatus in a copying machine, a document placing plate (for example, a platen glass) provided on the upper surface of an apparatus main body, and an upper side of the platen glass and swingable with respect to the apparatus main body via a hinge. There is known one provided with a manuscript pressing plate to be attached.
[0003]
In this type of document reading apparatus, it is necessary to close the document pressing plate horizontally in order to bring the document into close contact with the platen glass.
[0004]
However, the original pressure plate cannot be closed horizontally due to variations in dimensions of the original pressure plate and parts for attaching the original pressure plate to the apparatus main body, variations in rotational torque of the hinge, deformation due to its own weight moment, and the like. In other words, there is a case where a gap is generated between the platen glass and the original pressing plate, and this causes a technical problem that the original on the platen glass is lifted and the image quality of the read image is deteriorated.
Further, in a document reading apparatus of the type in which an automatic document feeder (ADF) is built in a document crimping plate, such a gap causes a document transportation error, which causes document damage or copy mistakes. There was a technical problem.
[0005]
Therefore, as a technique for improving the grounding property of the document crimping plate, for example, a lift member for lifting the document crimping plate in the vertical direction is provided between the hinge and the rear end portion of the document crimping plate. There has been proposed an apparatus provided with adjusting means for adjusting (see Japanese Utility Model Laid-Open No. 7-14451).
Further, the support shaft is inserted into the stay fixed to the free end side of the hinge and the rear end portion of the original pressure plate, and the diameter of the shaft hole for inserting the support shaft provided on the hinge side is set to the shaft provided on the stay side. There has also been proposed one that is formed to be larger than the hole diameter (see Japanese Patent Application Laid-Open No. 9-105267).
[0006]
[Problems to be solved by the invention]
However, in the former method, since the original pressing plate is always positioned at the same position, there is no allowance for dimensional change or deformation over time, and a gap is immediately generated with the occurrence of such dimensional change or deformation. As a result, a height adjustment by the adjustment means must be performed each time, and accordingly, there has been a technical problem that the reliability is lowered and the maintenance cost is increased.
[0007]
On the other hand, in the latter method, there is certainly a margin for absorbing dimensional changes and deformation over time by the difference between the hole diameters of the shaft hole provided on the hinge side and the shaft hole provided on the stay side. Since it is difficult to increase the difference in hole diameter, it is not possible to make a large margin for gap adjustment. If a large gap occurs for some reason, it is necessary to replace parts. There was a problem.
[0008]
The present invention has been made to solve the above technical problem, and provides an original reading apparatus capable of stably adhering an original pressing plate to an original on an original placing plate over a long period of time. To do.
[0009]
[Means for Solving the Problems]
That is, the present invention includes an apparatus main body including a document placement plate on which a document is placed, a document pressure plate that presses the document on the document placement plate, and an opening / closing mechanism that opens and closes the document pressure plate. The opening / closing mechanism includes: a fixing member attached to the apparatus main body; a frame member pivotally supported at one end with respect to the fixing member; and a free end side of the frame member Provided on the swing end side of the frame member with respect to the support member, and the document press plate is directed in a direction opposite to the closing direction. and a biasing means for biasing, when closing the original cover, the side original cover close to the swinging end of the frame member with contacting the document placing plate above, the frame member by said biasing means Place the original cover near the free end of the Characterized in that so as to add the weight rotation moment only brought into contact with the draft mounting plate.
[0010]
In such a technical means, the document placing plate may be a flat plate formed of a transparent material, for example, a reading glass (platen glass) formed in a long flat plate shape is used. be able to.
[0011]
The original pressing plate may be selected as appropriate so long as it can press the original placed on the original placing plate, and an automatic original feeder (ADF) is provided therein. It may be.
[0012]
Further, the frame member is supported at one end portion so as to be swingable with respect to a fixing member attached to the apparatus main body, and on the free end portion side, the original pressure plate is swingably supported. A supporting member is attached. Furthermore, an urging means for urging the original pressure plate in the direction opposite to the closing direction of the original pressure plate is provided on the fixed end side of the mounting position of the support member.
[0013]
The biasing means may be selected as appropriate as long as it can bias the original pressure plate in the direction opposite to the closing direction of the original pressure plate. For example, a compression spring or the like can be used.
Here, from the viewpoint of easily adjusting the urging force by the urging means, it is preferable to provide an adjusting means for adjusting the urging force by the urging means.
[0014]
Further, from the viewpoint of stabilizing the document pressing plate at the time of opening and closing and improving the grounding property with respect to the document placing plate, the center of gravity of the support member , the urging means, and the document pressing plate is collinear. It is preferable to arrange | position .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
1A and 1B show an embodiment of a document reading apparatus to which the present invention is applied. 1A is a top view of the document reading apparatus, and FIG. 1B is a side view.
In the figure, a document reading apparatus according to the present embodiment includes, for example, a platen glass 11 as a document placing plate provided on the upper surface of the apparatus body 10 of an electrophotographic copying machine, and the platen glass 11 can be freely opened and closed. A document pressing plate 20 provided and an opening / closing mechanism 30 for opening and closing the document pressing plate 20 with respect to the platen glass 11 are provided.
[0016]
The document pressing plate 20 incorporates an automatic document transport device that automatically transports a document (not shown) to the platen glass 11. In the figure, reference numeral 21 is a transport mechanism for transporting a document, 22 is a document supply tray on which a document to be transported is placed, and 23 is a document discharge tray for discharging a document after completion of scanning. These are legs provided at positions corresponding to the four corners of the bottom of the original cover 20.
In the original cover 20, the transport mechanism 21 side is heavier than the original trays 22 and 23, so that the center of gravity is at the position indicated by the reference sign G in the drawing, that is, the transport mechanism 21 side.
[0017]
Further, the opening / closing mechanism 30 includes a fixed member 31 provided at one end of the apparatus main body 10, a movable member 32 pivotally attached to the fixed member 31, and a frame 33 fixed to the movable member 32. It has. Thereby, the frame 33 is swingable with respect to the apparatus main body 10.
The frame 33 includes arm portions 34 and 35 fixed to the movable member 32, a first spanning portion 36 that spans the tip portions of the arms 34 and 35, and the movable member 32 and the spanning portion. A second span 37 that spans the arm portions 34, 35 between the arm 36, and a shape that surrounds the original document crimping plate 20.
[0018]
Of the first hooking pass portion 36 of the frame 33 the free end side, the portion intersecting with the center of gravity line L _G extending from the center of gravity of the original cover 20, the supporting portion 40 for supporting the original cover 20 is provided ing.
As shown in FIGS. 2A and 2B, the support portion 40 is provided with a pin 36 a that protrudes upward from the first spanning portion 36, and corresponds to the pin 36 a on the side surface of the document crimping plate 20. A stop portion 20a is extended at a position where the pin 36a is engaged, and an engagement hole 20b having an oval shape and engaging with the pin 36a is provided at the center thereof. As a result, the original cover 20 can swing up and down around the support portion 40 in FIG.
[0019]
Further, in FIG. 1 (a), of the opposite side of the second hooking pass portion 37 and the first hooking pass portion 36 the support portion 40 is provided, at a portion intersecting the gravity line L _G is the original cover An urging device 50 is provided as urging means for urging the plate 20 upward in FIG. 1B, that is, in the direction opposite to the closing direction.
As shown in FIGS. 1A and 1B, the urging device 50 is provided with a pin 37 a that protrudes upward from the second spanning portion 37, and corresponds to the pin 37 a on the side surface of the original cover 20. A plate 28 is extended at a position where the pin 37a extends, and a through hole 28a having a circular shape and penetrating the pin 37a is provided at the center thereof. Thereby, the original cover 20 can be moved while sliding smoothly along the pins 37a.
[0020]
Further, a compression spring 51 is disposed between the second spanning portion 37 and the plate 28 and on the outer periphery of the pin 37a. An adjustment plate 52 having a plate shape is disposed on the upper side of the compression spring 51 and on the lower side of the plate 28. The adjustment plate 52 is also provided with a hole through which the pin 37a passes. The size of the adjustment plate 52 is set such that excessive sliding resistance is not generated, that is, it can be moved while sliding smoothly.
The plate 28 is provided with four adjustment screws 53 penetrating downward, and the tip of the adjustment screw 53 comes into contact with the adjustment plate 52.
[0021]
Next, the operation at the time of opening and closing the document reading apparatus according to the present embodiment will be described with reference to FIGS.
FIG. 3A shows a state where the original cover 20 is opened.
At this time, in the drawing, the right side of the original cover 20, that is, the urging device 50 side, is compressed downward by the compression spring 51 due to its own weight.
[0022]
When the original cover 20 is closed as shown in FIG. 3B, first, the right leg of the original cover 20, that is, the leg 27 (26) near the swinging end of the frame 33 is the main body. Contact with the platen glass 11. At this time, the original weight of the original pressing plate 20 is applied to the platen glass 11 and is balanced with the platen glass 11. Therefore, the compression spring 51 with reduced load is extended by the restoring force, and the original pressing is performed by the urging force. The plate 20 is pushed upward. Accordingly, a decrease in the self-weight rotation moment of the original cover 20 due to the contact is suppressed, and a self-weight moment that remains to close further remains on the original cover 20.
[0023]
Thereafter, as shown in FIG. 3C, the left leg of the original pressing plate 20, that is, the leg 25 (24) near the free end of the frame 33 comes into contact with the platen glass 11, and the original pressing plate 20 is Close completely.
[0024]
As described above, in the present embodiment, when closing the document crimping plate 20, the document crimping plate 20 on the side close to the swing end of the frame 33 is first brought into contact with the platen glass 11 and the swing end side of the frame 33 is placed. Since the original pressing plate 20 on the side close to the free end of the frame 33 is applied to the platen glass 11 by the biasing device 50 provided on the platen glass 11, the original pressing plate 20 is applied to the platen glass 11. Can be stably grounded horizontally.
[0025]
In addition, since the original cover 20 itself is swingably disposed, a margin for absorbing dimensional changes and deformation with time can be increased, and stable grounding can be obtained over a long period of time.
[0026]
The force for lifting the original cover 20 can be easily adjusted by changing the initial compression amount of the compression spring 51 by adjusting the screwing amount of the adjustment screw 53 that contacts the adjustment plate 52 of the urging device 50. . That is, the urging force by the compression spring 51 may be adjusted so as to be a force equivalent to the self-weight moment of the document pressing plate 20.
Therefore, for example, when the leg 25 (24) near the free end of the frame 33 of the original cover 20 is no longer in contact with the platen glass 11 for some reason, the adjusting screw 53 is tightened. The adjustment plate 52 is moved in the direction in which the compression spring 51 contracts to increase the biasing force, and the original pressure plate when the leg 27 (26) near the swing end of the frame 33 of the original pressure plate 20 contacts the platen glass 11. By further reducing the decrease in the self-weight rotating moment of 20, it is possible to improve the grounding property of the original cover 20.
[0027]
Further, in this embodiment, since the supporting portion 40 and the biasing device 50 on the gravity line L _G extending from the center of gravity G of the original cover 20 is provided, while a small supporting points, swingably It is possible to reliably prevent the left and right balance of the arranged original cover 20 from being lost.
[0028]
【The invention's effect】
As described above, according to the present invention, when closing the document crimping plate, the document crimping plate closer to the swinging end of the frame member is first brought into contact with the document placing plate, and the swinging end of the frame member is placed. Since the original pressure rotating moment is applied by the biasing means provided on the side so that the original pressing plate near the free end of the frame member is brought into contact with the original setting plate, the original pressing plate is applied to the original setting plate. Can be stably grounded horizontally, and the original pressure plate can be stably brought into close contact with the original on the original placement plate over a long period of time.
[Brief description of the drawings]
FIG. 1A is a top view of an embodiment of a document reading apparatus to which the present invention is applied, and FIG. 1B is a side view.
2A is a top view of a support portion, and FIG. 2B is a side view.
FIGS. 3A to 3C are schematic diagrams for explaining an opening / closing operation of the document reading apparatus according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Main body of an apparatus, 11 ... Platen glass, 20 ... Original pressure plate, 20a ... Stop part, 20b ... Engagement hole, 21 ... Conveyance mechanism, 22 ... Original supply tray, 23 ... Original discharge tray, 24-27 ... Leg, 28 ... Plate, 28a ... Through hole, 30 ... Opening / closing mechanism, 31 ... Fixed member, 32 ... Movable member, 33 ... Frame, 34, 35 ... Arm part, 36 ... First passing part, 36a ... Pin, 37 ... First two hooking passing portion, 37a ... pin, 40 ... support portion, 50 ... biasing device, 51 ... compression spring, 52 ... adjustment plate, 53 ... adjustment screw, G ... center of gravity, L _G ... gravity line

Claims (3)

An apparatus main body provided with a document placing plate on which a document is placed;
A document pressing plate for pressing the document on the document placing plate;
In an original reading apparatus provided with an opening and closing mechanism for opening and closing the original pressing plate,
The opening / closing mechanism includes a fixing member attached to the apparatus main body,
A frame member whose one end is pivotally supported with respect to the fixed member;
A support member that is provided on a free end side of the frame member, and supports the document pressing plate in a swingable manner;
An urging means provided on the rocking end side of the frame member with respect to the support member, and urging the document pressing plate in a direction opposite to the closing direction;
When closing the original cover, the side original cover close to the swinging end of the frame member with contacting the document placing plate previously, the side original cover closer to the free end of the frame member by said biasing means A document reading apparatus characterized in that a self-rotation moment sufficient to bring the document into contact with the document placing plate is added. The document reading device according to claim 1,
An original reading apparatus comprising adjusting means for adjusting an urging force by the urging means. The document reading device according to claim 1,
An original reading apparatus, wherein the support member, the urging means, and the center of gravity of the original pressing plate are arranged on the same straight line.

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