JP2000137302A - Image reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent even a thin original from floating by giving a sufficient pressing force to it, to make the operability and the durability of an original pressing plate excellent with a simple constitution and to enable an original pressing device to be made lightweight and thin, besides. SOLUTION: By arranging a flexible lock member 147 flexibly receiving both of a first and a second pressing plates 141 and 142 when they are folded at a middle part, both plates 141 and 142 can be elastically locked by giving a proper angular range so as to soften colliding force when they are locked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus and an image forming apparatus having an original pressing plate for pressing an original on an original placing portion.

[0002]

2. Description of the Related Art Generally, an image reading device such as a scanner,
In various image forming apparatuses such as a printer, a copying machine, a plotter, and a facsimile, which use an electrophotographic method, a document on a document placing section is pressed from above by a document pressure plate attached to the apparatus main body so as to be openable and closable. The original is brought into close contact with the original platen glass.

[0003] For example, the original pressure plate 1 shown in FIG.
Has a so-called center-bending type structure in which two pressure plates 2 and 3 are rotatably connected. In this device, one of the first pressure plates 2 is connected to an apparatus main body (not shown). The second pressure plate 3 is attached to the pivoting side edge of the first pressure plate 2 via a hinge 5 as a rotation connecting means, and is bent and oscillated. It is connected as possible.

A flexible white plate 6 is stretched on the back side (the upper side in FIG. 8) of the first pressure plate 2 and the second pressure plate 3 so as to cover the hinge 5. By pressing the white plate 6 on the original and pressing it down, the pressure plates 2 and 3 are bent along the surface of the original. For example, in FIG. 6 showing the case of the present invention,
A book manuscript B, which is a representative of a thick manuscript, is used. The above-mentioned two pressure plates 2 and 3 are bent in a mountain shape along the cover of the book manuscript B, and the whole of the manuscript pressure plate 1 comes into close contact with the manuscript B. It will be. By holding down the original pressing plate 1 with the hand force F, the adhesion of the original to the original glass platen is improved, and the positional deviation is prevented.

Returning to FIG. 8, a projection engaging portion 7 which constitutes an opening angle restricting means is provided on an edge portion of the first pressure plate 2 at a portion facing the first pressure plate 2 and the second pressure plate 3. A groove-shaped engaging portion 8 for accommodating the projection engaging portion 7 is provided in the second pressure plate 3 side, and the first pressure plate 2 and the second pressure plate 3 are formed as described above. As shown in FIG. 6, when bent into a mountain shape, the tip edge portion of the projection engaging portion 7 comes into pressure contact with the inner wall surface of the groove-shaped locking portion 8 so that the first pressure plate 2
The second pressure plate 3 and the second pressure plate 3 are firmly locked to each other. As a result, the bending angle between the two pressure plates 2 and 3 is rigidly regulated.

Although not shown, a rigid plate-like member may be used instead of the above-described projection engaging portion 7. The rigid plate-shaped member is welded or screwed to a hinge 5 or the like serving as a rotation connecting means. When the rigid plate-shaped member is attached to the hinge 5, the first pressure plate 2 and the second pressure plate 3 are maximal. When bent at an angle, the swing substrates 5a and 5b of both the hinges 5 are rigidly locked via the rigid plate member.

[0007]

However, in the conventional apparatus having the above-described opening angle restricting means, the bending angle between the first pressure plate 2 and the second pressure plate 3 is rigidly set to one restriction angle. Therefore, when the angle is set to a regulation angle corresponding to a thick document as shown in FIG. 6, it is possible to press the document with the two pressure plates 2 and 3 constrained to the regulation angle. However, in the case of a thin document, the pressing operation of the document cannot be performed with a sufficient force because the two pressure plates 2 and 3 are freely rotated. As a result, the adhesion to the platen glass may be insufficient and the document may be lifted, and a good image reading operation may not be performed.

Further, when the pressure plates 2 and 3 are regulated by the opening angle regulating means, the pressure plates 2 and 3 collide with each other. Damage such as cracks may occur, causing a decrease in the durability of the device. For this reason, measures such as increasing the thickness of the manuscript pressing plate and the rigid locking plate and increasing the contact area have been taken, but both measures increase the size of the manuscript pressing plate and increase its weight. There is a problem in that the operability of the document pressure plate is reduced, and the collision sound at the time of regulation may be rather increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to improve the operability and durability of a document pressure plate with a simple configuration without increasing the size and weight of the document pressure plate. It is another object of the present invention to provide an image reading apparatus and an image forming apparatus capable of performing good image formation.

[0010]

According to a first aspect of the present invention, there is provided an original pressing plate for pressing an original placed on an original placing portion of an apparatus main body. A first pressure plate attached to the apparatus main body so as to be openable and closable, a second pressure plate foldably connected to the first pressure plate via rotation connection means, An opening angle regulating means for regulating a bending angle between the second pressure plates, wherein the opening angle regulating means is fixed to at least one of the first and second pressure plates. Including a flexible locking member,
The flexible locking member is disposed so as to elastically contact the other pressure plate when the first pressure plate and the second pressure plate are bent.

According to the second aspect of the present invention, the flexible locking member according to the first aspect is configured such that when the first pressure plate and the second pressure plate are bent, the other pressure plate or the rotation connecting means is provided. It is attached in a positional relationship that abuts on.

Further, according to the third aspect of the present invention, the flexible locking member according to the first aspect further comprises a fixing portion fixed to one of the first and second pressure plates, and A leaf spring portion extending from the fixed portion toward the other pressure plate, and a gap corresponding to a free rotation angle range between the two pressure plates is provided between the leaf spring portion and the other pressure plate. Is formed.

Further, in the invention described in claim 4, the leaf spring portion described in claim 3 and the pressure plate on the other side abut each other at a predetermined interval in the vertical bending direction of the leaf spring portion. The contact is in a positional relationship.

On the other hand, an image forming apparatus according to a fifth aspect of the present invention includes the above-described image reading apparatus according to the first, second, third, or fourth aspect.

According to the first and second aspects of the present invention, when the first pressure plate and the second pressure plate are bent, the two pressure plates are flexibly received by the flexible locking member. The two pressure plates are elastically locked with an appropriate angle range, and even if the opening angle of the two pressure plates changes from a small to a large opening angle from a thin original to a thick book original, it is sufficient for the original. The pressing force is applied to prevent the document from being lifted. In addition, since the collision force when the two pressure plates are locked is reduced by the flexible locking member, the operation of the document pressure plate is performed quietly, the durability is enhanced, and the rigidity of the document pressure plate and the like is reduced. Since it is not necessary to increase the height, the weight and thickness of the document pressing device can be reduced, and the operability of the document pressing plate is improved.

At this time, as in the invention according to claim 3,
If a gap for freely rotating the first pressure plate and the second pressure plate is provided, the setting operation of the original is particularly easily and reliably performed by using the free rotation.

According to the fourth aspect of the present invention, if the plate spring as the flexible locking member is configured to contact the pressure plate in both bending directions, it is possible to obtain a simple structure.
The above-described operation can be obtained in both upper and lower bending directions of the first pressure plate and the second pressure plate.

Further, in the image forming apparatus according to the fifth aspect of the invention, a similar effect can be obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, an outline of an image forming apparatus having an image reading device will be described using an electrophotographic copying machine as an example. Keep it.

In the electrophotographic copying machine shown in FIG.
An original glass table 12 as an original table is provided on the upper surface of the apparatus main body 11, and an original platen 14 according to the present invention that presses an original 13 placed on the original glass table 12 can be opened and closed. Attached to. The structure of the document pressure plate 14 will be described later.

A scanner device (scanning optical device) 15 constituting image reading means is provided directly below the document glass table 12. This scanner device 15
An illumination lamp 15a for irradiating the original 13 on the original glass table 12 with scanning light is provided.
The reflection mirror 15b and the projection lens 1 that guide the reflected light from the light source 3 to an image carrier (hereinafter, referred to as a photosensitive drum) 16 described later.
5c.

A photosensitive drum 16 is provided below the scanner device 15 so as to rotate clockwise in the drawing. Around the photosensitive drum 16, a charger 17 for uniformly charging the photosensitive drum 16, and a toner is applied to an electrostatic latent image formed on the photosensitive drum 16 by exposing the reflected light from the scanner device 15 to light. A developing device 18 for supplying the toner image to make it visible, a transfer charger 19 disposed in the middle of the paper transport path for transferring the toner image on the photosensitive drum 16 to the recording paper side, and separating the recording paper after the transfer. And a cleaning device 22 that removes, collects, and discharges the toner remaining on the photosensitive drum 16 after transfer, and the like, are sequentially arranged along the rotational driving direction of the photosensitive drum 16.

The paper feed path 23 extending from the transfer charger 19 and the separation charger 20 to the outlet of the apparatus main body 11 has an outlet end for thermally fixing the toner image on the recording paper. A fixing device 24 is disposed, and a paper discharge conveyance path 26 extends from an outlet of the fixing device 24 toward a paper discharge tray 25 attached to an outlet of the apparatus main body 11.
A discharge roller 27 is disposed in the discharge conveyance path 26 near the exit of the fixing device 22.
A paper feed cassette 30 for storing cut recording paper is provided below the paper transport path 23 so as to constitute a paper feed unit.

At the outlet on the right side in the drawing of the paper feed cassette 30, a paper feed roller 31 for feeding out the recording paper placed in the paper feed cassette 30 is arranged. Roller 31 to photosensitive drum 1
The transport path 32 extends toward the transfer area No. 6. In the vicinity of the transfer area in the transport path 32, a registration roller 33 for sending the recording paper to the transfer area in synchronization with the image forming process is provided. A registration sensor (not shown) for monitoring the paper conveyance state is disposed upstream of the registration rollers 33 in the conveyance direction.

Next, the structure of the document pressing device according to an embodiment of the present invention will be described. Original document pressure plate 14 described above
Are shown in FIGS. 1, 2 and 3. The document pressure plate 14 according to the present embodiment has a so-called center-fold type structure including a first pressure plate 141 and a second pressure plate 142. The first pressure plate 141 is formed of the first pressure plate 14.
A pair of hinge units 14 provided at one base end portion
It is openably and closably attached to the above-described apparatus main body 11 (see FIG. 7) via the holes 3 and 143.

Further, a pair of hinges 1 as a rotation connecting means is provided at an end portion on the swinging side opposite to the first pressure plate 141.
The second pressure plate 142 is connected to bend and swing through 44 and 144. These first pressure plate 141 and second pressure plate 141
The back side of the pressure plate 142, that is, the above-described original glass table 1
On the side facing the second side, a white plate 145 is stretched so as to cover the hinges 144 and 144, and the white plate 145 directly contacts and separates from the document glass table 12. It is supposed to be. The white plate 145 is
For example, it is formed by laminating a white sheet on the surface of an elastic substrate made of sponge or the like, and is fixed to the platen by an adhesive member or the like.

As is well known, each hinge 144 has a pair of swinging boards 144a and 144b which are connected to each other so as to be rotatable about an axis by abutting each end of the swinging boards 144a and 144b. , 144b are connected to the first pressure plate 14.
The first pressure plate 141 and the second pressure plate 142 are fastened and fixed to a plurality of cylindrical fixing boss portions 141a and 142a projecting from the first and second pressure plates 142 by a plurality of screw screws 146. As shown by a two-dot chain line in FIG. 3, they are connected to be able to bend in an inverted mountain shape and a mountain shape, respectively, in both the upper and lower directions.

At this time, as shown in FIG. 2, the maximum opening angle θ1 upward and the maximum opening angle θ2 downward between the first pressure plate 141 and the second pressure plate 142 are calculated as follows. It is regulated by the upper open angle restricting means and the lower open angle restricting means as described above.

First, the upper opening angle restricting means is provided by the first
The end faces of the pressure plate 141 and the second pressure plate 142 are in contact with each other, and more specifically, the first pressure plate 1
The two opposing end surfaces 141b, 142b in the connection portion between the first pressure plate 141 and the second pressure plate 142 are formed as inclined contact surfaces, and the opposing end surface 141b on the first pressure plate 141 side is formed as an oblique contact surface forming an obtuse angle. With the second pressure plate 142
The opposite end surface 142b is formed as an inclined contact surface forming an acute angle, and these inclined contact end surfaces 141b, 142b are formed.
The two first pressure plates 14 are brought into contact with each other in the inverted mountain-shaped maximum open state forming the upper maximum open angle θ1 described above.
The first and second pressure plates 142 are locked, and are regulated so as not to open any more.

At this time, the upper maximum opening angle θ1 is determined by the first
Both inclined contact surfaces 1 of the pressure plate 141 and the second pressure plate 142
In this embodiment, the maximum opening angle θ is determined in consideration of the operability of the document pressure plate 14.
1 is set in the range of 10 ° to 30 °.

On the other hand, the lower opening angle restricting means has a flexible locking plate 147 attached to the hinge 144. That is, the flexible locking plate 147 has a thickness of 0.5 mm to 1 mm.
The fixed portion 147a of the flexible locking plate 147 is overlapped with the fixed portion of the one swing substrate 144a of the hinge 144 described above. The plate spring portion 147b, which is fixed by joint tightening with the screw screw 146 and extends from the fixing portion 147a so as to be bent in a stepwise manner, is provided with the both swinging plates 144a and 144a of the hinge 144.
It extends slightly apart from the bottom 144b so as to overlap substantially in parallel. That is, the leaf spring portion 147b of the flexible locking plate 147 is supported to be elastically deformable in a cantilevered free flexible state.

At this time, the leaf spring portion 147b of the flexible locking plate 147 and the swing substrates 144a, 144 of the hinge 144 are provided.
44b is set to “a”, and the first pressure plate 141 and the second pressure plate 141 are separated by an amount corresponding to the gap “a”.
When the pressure plate 142 freely rotates and bends downward in a mountain shape, the free distal end portion of the leaf spring portion 147b is in a positional relationship in which the hinge 144 flexibly abuts on the swing substrate 144b side of the hinge 144. . The two pressure plates 141,
When 142 are bent further downward,
The leaf spring portion 147b is elastically bent, and the reaction force of the
41 and 142 are elastically locked.

At this time, the lower maximum opening angle θ2 between the two pressure plates 141 and 142 is determined by the above-described interval “a” and the spring coefficient of the leaf spring portion 147b. Is set to a relatively small value of, for example, about 1 mm. When the lower open angle between the two pressure plates 141 and 142 is relatively small,
A configuration is such that a free tip portion of 47b is in contact with the swing substrate 144b side. That is, the two pressure plates 141, 1
42 are elastically held at a relatively small opening angle, and when the maximum opening angle θ2 described above is reached, a spring coefficient that generates a locking force close to rigidity so that the opening angle does not increase further. Is set.

In such an embodiment, the first pressure plate 141
When the second pressure plate 142 and the second pressure plate 142 are
41 and 142 are flexibly received by the flexible locking member 147, and the pressure plates 14 are provided with an appropriate angle range.
1,142 will be in an elastic locking state. Therefore, from a thin document to a thick book document,
Even if the proper angles of the open angles 41 and 142 do not match, a sufficient pressing force (refer to the symbol F in FIG. 6) is applied to the document so that the document is prevented from floating. Has become.

Further, since the collision force when the two pressure plates 141 and 142 are locked is reduced by the flexible locking member 147, the operation of the document pressure plate 14 is performed quietly and the durability is enhanced. Can be Furthermore, since it is not necessary to increase the rigidity of the document pressing plate 14 and the like as in the related art, the weight and thickness of the document pressing device can be reduced, and the operability of the document pressing plate 14 is improved.

On the other hand, in the original pressure plate 34 according to another embodiment shown in FIGS. 4 and 5, a pair of hinge units 343, 3 provided at the base end portion of the first pressure plate 341 are provided.
Reference numeral 43 is attached to the apparatus main body 11 (see FIG. 7) so that the original pressure plate 34 can be opened and closed.

A wide turning base 344 projecting toward the second pressing plate 342 protrudes from a bent edge portion of the first pressing plate 341, and the turning base 344 in the plate width direction. Projection shaft 344 provided to project from both end surfaces
The enlarged front end portion a is inserted and locked so as to push open a bearing hole formed through the longitudinal rib plate 342a of the second pressure plate 342. The protrusion shaft 344a is
The first pressure plate 341 and the second pressure plate 342 are connected so as to be bent and swingable.

At this time, the upper maximum opening angle θ1 and the lower maximum opening angle θ2 between the first pressure plate 341 and the second pressure plate 342 are set.
(See FIG. 2) is regulated by one opening angle regulating means as described below.

That is, the opening angle restricting means in this embodiment has a flexible locking plate 347 which also serves as the upper and lower opening angle restricting means. In this flexible locking plate 347,
The fixing portion 347a is fastened and fixed to a bent edge portion of the first pressure plate 341 by a fixing screw 346, and the leaf spring portion 347b extends toward the second pressure plate 342 so as to be bent stepwise from the fixing portion 347a. Is out.

Further, an angle regulating narrow hole 348 for receiving the leaf spring portion 347b is formed in the lateral rib plate 342c of the second pressure plate 342 in a wide shape so as to penetrate the angle rib. The leaf spring portion 347b is inserted in a loosely fitted state. A predetermined gap is formed between each of the leaf spring portions 347b and the upper and lower edges of the angle regulating narrow hole 348. When the first pressure plate 341 and the second pressure plate 342 are bent in the vertical direction by an amount corresponding to the gap, the above-described leaf spring portion 347 is provided.
b, the free front end portion abuts on the upper and lower edges of the angle regulating narrow hole 348 and flexes elastically.
The two are elastically locked.

At this time, the maximum vertical opening angles θ1 and θ2 of the pressure plates 341 and 342 in the vertical direction are determined by the distances between the above-described leaf spring portion 347b and the upper and lower edges of the angle regulating narrow hole 348, and The distance is determined by the spring coefficient of the leaf spring portion 347b, but the interval in the present embodiment is set to be relatively small, and when the vertical opening angle between the two pressure plates 341 and 342 is relatively small, the leaf spring Part 347
The free front end portion b is brought into contact with the upper and lower edges of the angle regulating narrow hole 348. That is, the double pressure plate 34
1 and 342 are elastically held at a relatively small opening angle, and when reaching the maximum opening angles θ1 and θ2 described above, a locking force close to rigidity is generated so that the opening angle does not increase any further. The spring coefficient is set to

In such an embodiment, in addition to the operation of the above-described embodiment, the first pressure plate 341 and the second pressure plate 34
2 is flexibly controlled in the bending operation in both the up and down directions, and good operability and durability can be obtained. Moreover, since the configuration is simple, good productivity can be obtained at low cost.

Although the invention made by the present inventor has been specifically described based on the embodiment, the invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say. For example, in each of the above-described embodiments, a leaf spring is used as the flexible locking member. However, the present invention is not limited thereto, and various kinds of elastic members such as a coil spring may be replaced with the flexible locking member. Can be adopted.

Further, the scope of application of the present invention is not limited to the above-described copying machine, but it is naturally applicable to other electrophotographic image forming apparatuses having a document table. .

[0045]

As described above, the document pressing device of the image forming apparatus according to the first or second aspect of the present invention, when the first pressure plate and the second pressure plate are bent in the middle, the two pressure plates are separated from each other. By providing a flexible locking member for receiving flexibly, the pressure plates are brought into an elastic locking state with an appropriate angle range, so that the collision force when the pressure plates are locked is reduced. With a simple configuration, a sufficient pressing force can be applied to a thin document to prevent the document from being lifted, and the operability and durability of the document pressure plate are improved, and the weight of the document pressing device is reduced. It is possible to reduce the thickness, and it is possible to perform favorable image formation while improving the productivity of the apparatus.

At this time, according to the third aspect of the present invention, a gap for freely rotating the first pressure plate and the second pressure plate is provided,
Since the original setting operation and the like are made easier and more reliable, the above-described effects can be further enhanced.

Further, according to the fourth aspect of the present invention, the plate spring as the flexible locking member is configured to abut on the pressure plate in both bending directions, so that the first pressure plate and the second pressure plate can be further simplified. Because it is configured to obtain the above-described actions and effects in both the upper and lower bending directions of the pressure plate,
The above effects can be further improved.

Further, the fifth aspect of the present invention has the same structure as that of each of the above-mentioned aspects, and thus can provide the same effects.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing a structure of an original pressure plate according to an embodiment of the present invention when viewed from the back side.

FIG. 2 is an explanatory side view of the document pressing plate shown in FIG. 1;

FIG. 3 is a partially enlarged side view illustrating a main part of the document pressing plate shown in FIG. 2;

FIG. 4 is an explanatory plan view showing a structure of a document pressing plate according to another embodiment of the present invention when viewed from the back side.

FIG. 5 is a partially enlarged side view illustrating a main part of the document pressing plate shown in FIG. 4;

FIG. 6 is an explanatory side view showing a state in which a book original is pressed by the original pressing plate according to the present invention.

FIG. 7 is an explanatory side view showing a schematic structure of a copying machine as an example of an image forming apparatus to which the present invention is applied;

FIG. 8 is an explanatory perspective view showing the appearance of a conventional document pressing plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Device main body 12 Document glass board (document mounting table) 13 Document 14 Document pressure plate 141 1st pressure plate 142 2nd pressure plate 144 Hinge (rotation connection means) 144a, 144b Oscillating board 147 Flexible locking plate (open angle regulation) Means I 147a Fixed part 147b Leaf spring part a Gap 34 Original pressure plate 341 First pressure plate 342 Second pressure plate 344a Projection shaft 347 Flexible locking plate (opening angle restriction means) 347a Fixed part 347b Plate spring part 348 Angle restriction narrow hole (Opening angle regulating means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiyuki Koshimizu 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H012 CB01 CB12 CB28

Claims (5)

[Claims] A first pressure plate attached to the document main body so as to open and close the document main body; A second pressure plate connected to the first pressure plate via a rotation connection means so as to be bent;
An opening angle restricting means for restricting a bending angle between the first pressure plate and the second pressure plate, wherein the opening angle restricting means is at least one side of the first pressure plate and the second pressure plate. A flexible locking member fixed to the pressure plate, wherein the flexible locking member is arranged so as to elastically abut on the other pressure plate side when the first pressure plate and the second pressure plate are bent. An image reading apparatus, comprising: 2. The flexible locking member according to claim 1, wherein the flexible locking member is attached in a positional relationship to abut on the other side pressure plate or the rotation connection means when the first pressure plate and the second pressure plate are bent. The image reading device according to claim 1. 3. A fixing portion fixed to a pressure plate on one of a first pressure plate and a second pressure plate;
A leaf spring portion extending from the fixed portion toward the other pressure plate; and a gap corresponding to a free rotation angle range between the two pressure plates between the leaf spring portion and the other pressure plate. 2. The image reading device according to claim 1, wherein the image reading device is formed. 4. The leaf spring portion and the other side pressure plate are in a positional relationship in which the leaf spring portion abuts with each other at a predetermined interval in the vertical bending direction of the leaf spring portion. 3. The image reading device according to 3. 5. An image forming apparatus according to claim 1, further comprising: the image reading apparatus according to claim 1. Description: