JP3573884B2 - Image reading device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus that reads a document image while passing the document on a short slit glass in a transport direction, and more specifically, a device that can transport the document to a reading position without affecting the image quality of the read image. About what you did.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image reading apparatus mounted on a copying machine, a facsimile apparatus, or the like has been known. In this image reading apparatus, an image reading unit captures reflected light of light applied to a document and reads the document image. ing.
As this type of image reading apparatus, there is an image reading apparatus which is equipped with an automatic document feeder that automatically feeds a document to a reading position by passing a document through a paper path, and employs a so-called sheet-through method. The automatic document feeder reads an original image by passing the original on a short slit glass in the transport direction with the optical system of the image reading means stopped. An image reading apparatus employing the sheet through system is described in, for example, Japanese Patent Application Laid-Open No. HEI 3-23137.
[0003]
[Problems to be solved by the invention]
However, in such a conventional image reading device, the original is read from the upstream side of the reading position by contacting the leading end or the image surface with the slit glass and sliding the upper surface thereof to read the image. If the setting is made and the original image is formed by transferring a recording medium such as toner, the one with weak adhesion of the recording medium may be peeled off due to the contact resistance with the slit glass, A minute foreign matter may adhere to the image surface of the document and be conveyed. In this case, when the document is conveyed onto the slit glass and slid, the recording medium or foreign matter adheres to the reading position due to the contact resistance with the slit glass and remains as dust, so that a straight line in the sub-scanning direction appears. The image is read as an image formed on a document, and as shown in FIG. 3, when a read image is recorded and output, black streaks A (for example, A1 to A3 shown in FIG. 3) are recorded on recording paper P. There was a problem that it would be formed.
[0004]
Note that the black streaks A1 to A3 shown in FIG. 3 indicate the reading position when the recording medium of the previously read original remains at the reading position or when the recording medium remains at the reading position when reading the original. And that the length in the sub-scanning direction changes depending on the timing at which the image is rejected.
In view of the above, the present invention is designed to read an image without sliding the image surface of the document to the reading position of the slit glass, thereby preventing dust from adhering to the reading position and lowering the image quality of the read image. The purpose is to prevent.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a reflected light of linear light radiated through a slit glass onto a document passing over a reading position of a slit glass shorter than a length of the document in a conveying direction. Image reading means for reading an image by taking in a document, and document conveying means for conveying the document by passing it through a paper passing path for guiding the document on the slit glass, wherein the reading position is adjacent to the reading position. A guide member that constitutes the lower surface of the paper passing path located above the upstream side of the paper feeder. The guide member has a guide surface formed by notching a corner portion in a tapered shape, and guides the document by the guide surface. conveyed in a state of being floated from the slit glass top immediately after the surface, the image reading reading position means in proximity to the downstream end of the guide member, the shape between said image reading means and the slit glass image surface of the document Is characterized in that reading the image capturing reflected light that has been reflected through the space is irradiated with light through the space to be.
[0006]
According to the first aspect of the present invention, the reading position of the document image is close to the downstream end of the guide member having the guide surface for guiding the conveyed document positioned above the upstream side. The original image is arranged below the document conveyed in a state of being floated from the upper surface of the slit glass immediately after the guide surface, and the original image captures the reflected light irradiated and reflected through the space between the image surface and the slit glass. Read by Therefore, the original does not slide on the reading position on the slit glass, and there is no possibility that the recording medium or foreign matter adheres to the reading position due to contact resistance with the slit glass and remains at the reading position.
[0007]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, a position adjusting unit that moves an optical system of the image reading unit in a document conveying direction and adjusts a reading position of the image reading unit. Is provided.
According to the second aspect of the present invention, the reading position of the document image can be adjusted by moving the optical system of the image reading means in the document conveying direction by the position adjusting means. Therefore, the reading position of the document image can be easily adjusted according to the state of the apparatus and the nature of the document to be handled. For example, by providing a position adjusting means for switching the reading position by a service person or the like, or by the user The reading position can be easily adjusted by providing a switch or the like for switching the reading position to a setting position corresponding to the waist or the like as the position adjusting means.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings.
1 and 2 are views showing an embodiment of an image reading apparatus according to the present invention, and show an example mounted on an image forming apparatus.
First, a schematic configuration of the image reading device will be described.
[0009]
In FIG. 1, reference numeral 1 denotes a copying machine (image forming apparatus) provided with an image reading apparatus. A slit glass 2 and a contact glass 3 are provided on an upper surface of the copying machine 1, and the slit glass (reading position) 2 Below the contact glass 3, an exposure lamp 4 as an image reading means and a first mirror 5 are provided. When reading the document P set on the contact glass 3, the image reading means of the copying machine 1 moves the exposure lamp 4 and the first mirror 5 horizontally below the contact glass 3 to move the document P When the original P is read through the slit glass 2 and the exposure lamp 4 and the first mirror 5 are stopped below the slit glass 2, the image plane of the original P is read. The reading method is publicly known and will not be described in detail. However, the first mirror 5 or a lens (not shown) couples the reflected light of the light irradiated by the exposure lamp 4 from the image surface to an imaging element such as a CCD. It is designed to image.
[0010]
An automatic document feeder (hereinafter, simply referred to as an ADF) 6 is mounted on the upper surface of the copying machine 1, and the lower surface of the ADF 6 covers the original P placed on the contact glass 3 so as to cover the contact glass 3. 3, a reflection plate 7 serving as a white reference when reading the document P is provided. The ADF 6 is connected to the copying machine 1 via a hinge (not shown), and is freely movable toward and away from the upper surface of the copying machine 1.
[0011]
Further, the ADF 6 is provided with a document table 9 at an upper portion, and a document bundle including a plurality of documents P is set (placed) on the document table 9. The document P set on the document mounting table 9 is sent out between the sheet feeding belt 11 and the sheet feeding preventing roller 12 (separating section) by the contacting rotation of the call roller 10 on the upper surface thereof. When the paper feed belt 11 rotates in the transport direction, and the paper feed prevention rollers 12 rotate in the opposite direction to the transport direction, the uppermost original P is separated and fed one by one. A stopper member 13 is provided downstream of the call roller 10 in the document conveying direction. The document P placed on the document table 9 is stopped by the stopper member 13 during standby and enters the paper feed belt 11 side. You are forbidden to do so. The paper feed belt 11 is in pressure contact with the paper feed prevention roller 12 at an arbitrary angle θ.
[0012]
A push-up plate 14 is provided below the call roller 10, and the push-up plate 14 is rotated by a solenoid (not shown) about a rotation fulcrum 14 a on the upstream side in the transport direction, and a tip end of the push plate 14 is moved relative to the call roller 10. To be close to and separated from each other. That is, when the copy start switch on the side of the apparatus main body 1 is pressed, the push-up plate 14 moves from a position indicated by a solid line separated from the call roller 10 to a position indicated by a virtual line close to the call roller 10. The document P is pressed against the call roller 10, and the document P is sent out by the call roller 10.
[0013]
The paper feed belt 11 is wound around a driving roller 15 and a driven roller 16 and housed in a case 17. The driving roller 15 is detachably mounted on the ADF 6 main body, and is mounted on a shaft 15a that is driven to rotate. A one-way clutch 21 is provided between the driving roller 15 and the shaft 15a. And rotates clockwise in the figure to drive the paper feed belt 11. On the other hand, the driven roller 16 is supported while being urged in a direction away from the driving roller 15 by a spring 20, and a constant tension is applied to the sheet feeding belt 11 by the spring 20. The case 17 is rotatably supported on a shaft 15a. The case 17 is provided with a revolving roller 10 which is connected to the shaft 15a via a transmission means (not shown) and is rotated. . The case 17 is positioned by being held down by an openable and closable paper supply unit cover 18, and the paper supply belt 11 is pressed and brought into contact with the paper supply prevention roller 12 by positioning the case 17. Then, the call roller 10 is also positioned. Conversely, if the case 17 rotates in the same direction about the shaft 15a as the fulcrum with the paper feeding unit cover 18 being rotated in the opening direction, the call roller 10 and the paper feeding belt 11 Can be opened. The paper feeding unit cover 18 is attached so as to be rotatable about a fulcrum 19.
[0014]
Here, the drive of the shaft 15a is transmitted to the calling roller 10 via a gap clutch (not shown). The gap clutch is a member having a meshing portion formed so as to transmit the drive of the shaft 15a to the call roller 10 while rotating the shaft 15a by a predetermined angle. When the vehicle rotates, the engagement for transmitting the driving force is released. For this reason, when the trailing end of the uppermost document P comes out of the call roller 10, the rotation of the shaft 15a is not transmitted to the call roller 10 until the rear end rotates by a predetermined angle, and the interval between the following document P is opened during that time. It has become. In order to exhibit such a function, the drive roller 15 and the call roller 10 may be driven via an electromagnetic clutch or a spring clutch instead of the gap clutch.
[0015]
Then, the document P separated by the paper feed belt 11 and the paper feed prevention roller 12 is nipped by a nip portion of a first transport roller 23 and a driven roller 24 that are driven to rotate by a motor (not shown), so that a reversal path (passage) is achieved. The paper is fed while being inverted along the paper path (paper path) 25 and is conveyed toward the slit glass 2. The driven roller 24 is attached to a lever 26 that is rotatably supported about a fulcrum 19 of the paper feeding unit cover 18. The first transport roller 23 is pressed by being pressed by the spring 27 that is positioned. In the drawing, reference numeral S denotes a registration sensor, and the registration sensor S detects the leading end of the document P in order to temporarily stop it in order to adjust the timing from the carry-out of the document P.
[0016]
The document P conveyed by the first conveyance roller 23 and the driven roller 24 is guided by a reversing guide 28 constituting a guide member, is conveyed onto the slit glass 2, passes therethrough, and is guided at the leading end by a reversing discharge guide 29. After being bent, the sheet is picked up and passed through the sheet discharge path 30. Thereafter, the sheet is sandwiched between the nip portions of the second transport roller 32 and the driven roller 33 and is discharged from the slit glass 2. The sheet is transferred to the discharge roller 34 and the driven roller 35 and discharged by the discharge brush 36 to be discharged onto the external cover 37 from the discharge path 30. That is, the first and second transport rollers 23 and 32 and the driven rollers 24 and 33 constitute a document transport unit. When the document P passes over the slit glass 2, the document image is read by the exposure lamp 4, the first mirror 5, and the like. On the slit glass 2, a reflection guide plate 31 is provided. The reflection guide plate 31 forms a part of the paper passage between the reversing path 25 and the paper discharging path 30 for maintaining the interval of the document P from the slit glass 2 constant together with the reversing guide 28 and the reversing discharging guide 29. And a reflection part of light from the exposure lamp 4 and a white reference at the time of reading. The speed of transport of the document P is set higher in the second transport roller 32 than in the first transport roller 23, and the document P passing over the slit glass 2 depends on the difference in the transport speed. The sheet is conveyed along the reflection guide plate 31 by the restoring force when it is deflected by 29, and the distance from the slit glass 2 is made constant.
[0017]
On the other hand, the reflection plate 7 that covers the contact glass 3 is provided on the lower surface of the pressing plate 38, and the pressing plate 38 presses the original P placed on the contact glass 3 against the glass 3. I have. The pressure plate 38 is rotatably mounted on a main frame 40 via a fulcrum 39. The main frame 40 has an end mounted on the shaft of the driven roller 35 and is fixed to the ADF 6 main body.
[0018]
The main frame 40 has an area that covers the contact glass 3, and an outer cover 37 is attached to the upper surface, and forms a document discharge table together with the outer cover 37. The pressing plate 38 is connected to an auxiliary frame 42 via a link 41. The auxiliary frame 42 is formed to have a substantially U-shaped cross section so as to sandwich the outer peripheral portion of the main frame 40, and a fulcrum 43. And is rotatably connected to the main frame 40. Further, a magnet 44 is provided on the main frame 40, and the magnet 44 sucks the auxiliary frame 42.
[0019]
The auxiliary frame 42 may be entirely made of metal, or may be entirely made of an elastic member such as plastic so that only the portion attracted by the magnet 44 is made of metal. A guide plate 42a that defines a part of the paper discharge path 30 is formed at the tip (left end in the figure) of the auxiliary frame 42, and the driven roller 33 is rotatably provided on the guide plate 42a. Then, the leading end of the document P guided by the reverse discharge guide 29 is guided to the nip portion between the second transport roller 32 and the driven roller 33.
[0020]
A stamp unit 45 is provided on the guide plate 42a. The stamp unit 45 is provided at a predetermined position on the downstream side in the transport direction of the document P passing through the slit glass 2 by causing the stamp to protrude and retract from the guide plate 42a by a solenoid. Is to be stamped. By imprinting this stamp, it is possible to confirm the completion of reading and to confirm a double feed failure of the document P. Further, a handle 46 is provided in a portion of the auxiliary frame 42 near the guide plate 42a, and the handle 46 can be gripped by a user. Further, a stopper 47 is provided on the main frame 40, and the stopper 47 abuts on a base end (right end in the figure) of the auxiliary frame 42, and the auxiliary frame 42 rotates counterclockwise around the fulcrum 43. It is prohibited to rotate more than a predetermined amount.
[0021]
Next, features of the present embodiment will be described.
In FIG. 2, the reversing guide 28 covers the upper surface on the upstream side adjacent to the slit glass 2 and fixes the slit glass 2 by being screwed to a frame 49 of the copying machine 1 main body.
The reversing guide 28 defines the lower surface of the reversing path 25 and guides the document P, which has been conveyed in the reversing path 25 by the first transport roller 23 and the driven roller 24, to pass over the slit glass 2. A guide surface 28a is formed at the downstream end located upstream and above the reading position R of the slit glass 2, and the document P guided by the guide surface 28a is located immediately after the guide surface 28a, that is, When the sheet is conveyed downstream from the end face 28b at the downstream end, the sheet is conveyed in a state of floating above the upper surface of the slit glass 2 and then slidably contacts the vicinity of the center of the slit glass 2 so that the reverse discharge guide 29 is picked up. I have.
[0022]
The exposure lamp 4 and the first mirror 5 stop at a position below the slit glass 2 and close to the end face 28b at the downstream end of the reversing guide 28. 5 irradiates light onto the image surface of the document P floating immediately after the guide surface 28a through a space formed between the document P and the slit glass 2, and passes through the space. The reading position R is set so as to read the image by deflecting and taking in the reflected light that has been reflected. Therefore, the original P does not slide on the reading position R on the slit glass 2, and dust 100 such as a recording medium or a foreign substance indicated by a broken line in FIG. Will not remain.
[0023]
The exposure lamp 4 and the first mirror 5 are moved by a mechanism (position adjusting means) (not shown) in the left-right direction in the figure to read the document P set on the contact glass 3, and the lower part of the slit glass 2. The stop position can be finely adjusted below the slit glass 2 by, for example, changing the driving amount of the motor or changing the set position of the position detection sensor. That is, the reading position R of the document P can be adjusted in the transport direction. Therefore, the reading position R can be easily adjusted after assembling with appropriate accuracy or according to the waist and thickness of the document P to be handled. The adjustment of the stop positions of the exposure lamp 4 and the first mirror 5 may be performed by, for example, a service person or the like. For example, it may be possible to change it.
[0024]
As described above, in the present embodiment, the reading position R of the document P is brought close to the downstream end of the reversing guide 28, and the document P is irradiated with light through the space between the slit glass 2 and reflected light thereof. Since the document image is read and the document image is read, the document image can be read without bringing the document P into sliding contact with the reading position R on the slit glass 2. Can be prevented from deteriorating the image quality of the read image.
[0025]
Further, the reading position R of the original image can be easily adjusted according to the state of the apparatus and the nature of the original to be handled because the stop position of the exposure lamp 4 and the first mirror 5 can be adjusted in the direction of conveyance of the original P. The accuracy at the time of assembling can be eased, and the reading position R can be easily set to a reading position R according to the use situation of the user.
[0026]
As another aspect of the present embodiment, although not shown, the reading position R is set near the center of the slit glass 2 because the reading of the document image is not performed by sliding the document P against the slit glass P. There is no need to set, and the reading position R can be brought close to the end face 28b at the downstream end of the reversing guide 28 to the extent that the light reflected on the document P is not blocked. The apparatus can be miniaturized by shortening it in the P transport direction. Further, the document P does not need to be brought into sliding contact with the slit glass 2, and the reversing discharge guide 29 may be directly scooped up, so that the size can be further reduced.
[0027]
【The invention's effect】
According to the first aspect of the present invention, by setting the reading position of the document image close to the downstream end of the guide member for guiding the document from above the upstream side, the slit is formed on the document floating above the slit glass upper surface. The original image is read by irradiating light through the space between the glass and the reflected light and taking in the reflected light, so that the original image can be read without sliding the original at the reading position on the slit glass. It is possible to prevent the image quality of the read image from deteriorating due to the attachment of the recording medium or foreign matter.
[0028]
Further, since the document image is not read by sliding the document on the slit glass, it is necessary to bring the reading position close to the downstream end of the guide member to such an extent that light reflected upon the document is not blocked. The size of the apparatus can be reduced by shortening the slit glass in the document conveyance direction. Also, when the original is slid on the surface of the member for picking up and discharging, the member does not need to be a slit glass, and the size can be further reduced.
[0029]
According to the second aspect of the present invention, the reading position of the document image can be adjusted by moving the optical system of the image reading means in the document conveying direction. It is possible to adjust easily and reduce the accuracy at the time of assembling, and it is possible to easily set the reading position according to the use situation.
[Brief description of the drawings]
FIG. 1 is a schematic overall configuration diagram showing an embodiment of an image reading apparatus according to the present invention.
FIG. 2 is an enlarged view showing a main part thereof.
FIG. 3 is an explanatory diagram for explaining the conventional problem.
[Explanation of symbols]
1 Copier (image reading device)
2 Slit glass 4 Exposure lamp (image reading means)
5 First mirror (image reading means)
6 ADF (automatic document feeder)
9 Document Placement Table 10 Recall Roller 11 Feeding Belt 12 Feeding Prevention Roller 23 First Transport Roller (Document Transport Means)
24 Followed roller (document conveying means)
25 Reverse path (paper passing path)
28 Reverse guide (guide member)
32 Second transport roller (document transport means)
33 Followed roller (document conveying means)
100 Garbage P Original R Reading position

Claims (2)

Image reading means for reading an image by taking in reflected light of linear light irradiated through the slit glass into a document passing over a reading position of the slit glass shorter than the length of the document in the conveying direction, and reading the document with the slit glass A document conveying means for passing the paper through a paper passing path guided upward, and conveying the document,
A guide member is provided adjacent to the reading position and forms a lower surface of the sheet passing path located on the upstream side of the reading position, and the guide member has a guide surface formed by notching a corner portion in a tapered shape. By the guide surface, the original is conveyed in a state of being floated from the upper surface of the slit glass immediately after the guide surface,
The reading position of the image reading unit is brought close to the downstream end of the guide member, and the image reading unit irradiates light through a space formed between the slit glass and the image surface of the document and irradiates the light through the space. An image reading apparatus that reads an image by taking in reflected light. 2. The image reading apparatus according to claim 1, further comprising a position adjusting unit configured to move an optical system of the image reading unit in a document conveying direction and adjust a reading position of the image reading unit.

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