JP2003221146A - Document feeder with document slip preventing function, and image reader and image forming device having the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress reduction in feed speed and prevent an elongation of a read image in a slow scan direction by reducing sliding resistance to a document. <P>SOLUTION: A document feeder 31 has a document path 25 for guiding and feeding a sheetlike document to an image reading point Q where an image on the document is read in slantingly from above and guiding and discharging it slantingly upward, pre-reading rollers 11 and pressure rollers 12 for delivering and feeding the document to the image reading point under the guidance of the document path, and paper discharge rollers 15 and paper discharge pressure rollers 16 for delivering and discharging the document from the image reading point under the guidance of the document path. A sidewall 20 for guiding the back surface of the document in the document path has upstream rib portions 202a (downstream rib portions 202a) for reducing sliding friction to the back surface of the document at least either between the pre-reading rollers and pressure rollers and a position opposed to the image reading point, or between the image reading point and the paper discharge rollers and paper discharge pressure rollers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeder used in an image forming apparatus such as a digital copying machine, a printer, a fax machine using a digital reading system, or a complex machine of these, and more particularly, a document feeding resistance. And a document feeding device that improves the reading accuracy of the document by reducing the number of documents, an image reading device that includes the document feeding device and reads the document with high accuracy, and an image reading device that includes the image reading device and prints a high quality image on a recording medium. And an image forming apparatus for forming the same.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus reads an original supplied by an original supplying apparatus with an image reading apparatus and forms an image on a sheet as a recording medium based on image information read by the image reading apparatus. There is something that has become.

The document feeder includes an automatic document feeder (Au) for automatically feeding a plurality of documents to an image reading device.
to Document Feeder, "AD
"F"). The ADF is arranged on the platen glass of the image reading device, and automatically supplies a plurality of originals to the reading position of the platen glass continuously.

On the other hand, in the image reading apparatus, since the document is automatically and continuously supplied from the ADF, the image reading unit for reading the image of the document is stopped at the image reading position, and the document passing through the image reading position is fed. It can be read one after another. This reading is generally called "flowing reading".

In the image reading device, the user can use AD
When F is opened with respect to the platen glass and one original is placed on the platen glass, the image reading unit can be moved to read the original. This reading is generally called "fixed reading".

Therefore, when the image reading apparatus scans a document by using the ADF, the ADF is required to constantly and stably supply the document to the image reading position. Moreover, an image reading device equipped with an ADF is capable of digital reading by rapid digitization in recent years, development of a high-speed digital copying machine equipped with a memory, installation in low-priced popular models, and even image reading on a personal computer or the like via a network. As the image input means for transferring the image, more accurate and high-speed image reading performance is required.

In particular, the ADF mounted on the image reading apparatus of the digital color reading system is required to have high carrying accuracy which is not available in the conventional analog reading system. An image reading device of a digital color reading system reads an image of a document being conveyed by an ADF in three colors of red, green, and blue (RGB), and then reads the read information in an image processing unit of the image reading device. Digital image processing. However, the document shakes (blurrs) during document transport by the ADF.
In addition, when the document is lifted at the image reading position, the read information appears as an image defect such as color shift or image distortion that cannot be corrected by digital image processing.

Further, in the ADF for scanning and reading a document with the optical system fixed, a document tray is arranged above the discharge tray so as to have a conveyance path for leading from the document tray to the discharge tray through the reading position. , U-turn path reduces the occupied area and downsizes the device.

FIG. 12 is a front sectional view showing a schematic structure of a copying machine which is an example of an image forming apparatus. FIG. 13 shows AD
FIG. 6 is an enlarged cross-sectional view of a main part of F, which is a cross-sectional view taken along a document conveyance direction. FIG. 14 shows A- in FIG.
FIG.

The copying machine 101 has an image reading apparatus (hereinafter referred to as a "scanner section") 90 as a component of the copying machine 101 on the upper part of the apparatus main body 121, and an ADF 8 having a U-turn path thereon. Is configured. A description of the internal configuration of the apparatus main body 121 and the scanner unit 90 will be omitted.

The document tray 1 is designed so that a user can place a document G on it. The width regulating plate 2 regulates the side portions of the document in order to make the width of the document G uniform. The pickup roller 3 descends to the position indicated by the broken line 3a, comes into contact with the upper surface of the uppermost document, picks up the document G, and feeds it into the main body 9 of the ADF 8.

The separating roller 4 is always in contact with the facing separating pad 5, and when a plurality of originals fed between the separating roller 5 and the separating pad 5 are overlapped with each other, the originals are frictionally separated and conveyed one by one. It has become. The first transport roller 6 and the transport roller 7 sandwich and transport the document.

The manuscript separated into sheets one by one is fed into the inner guide 1
0 and the outer guide 18 and travels downward on the conveying path that is curved and inclined, and is conveyed to the reading point Q via the pre-reading roller 11 and the reading pressure roller 12 immediately before the reading point Q. Reading guide 13
Is a member for guiding the back side of the document near the reading point Q.

A guide mylar 14 which is a transparent film member for guiding the front side of the document is provided on the side facing the reading guide 13. The reading guide 13
A flat surface portion 131 parallel to the original table glass 62 on the surface facing the reading point Q, an upstream inclined portion 132 that is curved and inclined continuously from the flat surface portion 131 to the upstream side, and from the flat surface portion 131 to the downstream side. It is formed by the downstream side inclined portion 133 which is continuously curved and inclined. Further, the reading guide 13 is attached to the main body 9 of the ADF 8 by a rotation fulcrum 13
It is rotatably provided by 4. Reading guide 13
Is urged toward the document table glass 62 by urging means (not shown). Further, as shown in FIG. 14, abutting projections 135, 135 are provided so as to project downward at both ends of the flat surface portion 131 in the direction orthogonal to the transport direction of the reading guide 13. This abutting protrusion 135 is a guide mylar 1.
4 and the reading guide 13 and the guide mylar 14
And a small distance d is generated between

Therefore, the guide mylar 14 is in contact with the original platen glass 62 in the vicinity of the reading point Q, and the original can read the image while passing through the guide mylar 14 and the original platen glass 62. Reading point Q
Originals that have passed through the
The sheet is discharged onto the discharge tray 17 by the sheet discharge roller 15 and the sheet discharge pressure roller 16. That is, the ADF 8 has a U-turn path 19 which is a document path from the document tray 1 to the discharge tray 17 through the reading point Q.

In the ADF 8 constituted by the U-turn path 19 as described above, image defects such as color misregistration and image distortion of the read image are caused by the impact at the moment when the trailing edge of the conveyed document leaves the pre-reading roller 11. This was caused by a sudden document shake (blurring) and floating of the document at the reading position when the document was conveyed by only the discharge rollers 15.

Therefore, conventionally, the shape of the side wall of the reading guide 13 for guiding the back side of the original has been set to a shape that does not cause the image defect. That is, the reading guide 13 prevents abrupt blurring and floating of the original document during conveyance and enhances the stable conveyance of the original document. Therefore, as shown in FIG. An upstream side inclined portion 132 extending from 131 to the upstream side in the transport direction, and a flat surface portion 1
31 has a downstream side inclined portion 133 connected to the downstream side in the transport direction, and the upstream side inclined portion 132 and the downstream side inclined portion 133 have large arc surfaces extending the flat surface portion 131.

In FIG. 15, when the rear end of the document G passes through the pre-reading roller 11 and the document is conveyed only by the paper discharge roller 15, the upstream side inclined portion 132 and the downstream side inclined portion 1 are shown.
33 is an enlarged view around 33 and a reading point Q. FIG. On the upstream side of the reading point Q, the reading guide 13 forms a large arc surface on the upstream side inclined portion 132 so as to extend the flat surface portion 131, and narrows the interval between the upstream side inclined portion 132 and the guide mylar 14 to read. Flapping of the document G when it has passed through the front roller 11 is absorbed in the vicinity of the upstream side inclined portion 132 to suppress the document blur near the reading point Q.

When the trailing edge of the document G has passed through the pre-reading roller 11 and is in the state of being conveyed by only the paper discharge roller 15, the document G is wound around the reading guide 13 in the vicinity of the downstream inclined portion 133. It is transported while floating. This is because the paper discharge roller 15 is generally set to be about 1% faster than the peripheral speed of the pre-reading roller 11 in order to prevent wasteful slack in the document being conveyed. At this time, when the downstream inclined portion 133 of the reading guide 13 is formed in a large arc surface so as to extend the flat portion 131, the document G is attached downward at the downstream inclined portion 133, and Prevents floating.

In FIG. 16, the upstream side inclined portion 132a and the downstream side inclined portion 133a are not formed in a large arc surface extending the flat surface portion 131a.
It is the figure which showed one example which escaped so that a and the downstream side inclination part 133a and the guide mylar 14 may be opened. In such a configuration, on the upstream side of the reading point Q, a space in which the upstream end of the document G flutters becomes large, and at the same time, the document G near the reading point Q may float up by the waist.

As described above, in the ADF 8 having the U-turn path 19, the upstream side slanted portion 132 and the downstream side slanted portion 133 of the reading guide 13 prevent abrupt blurring and floating during the conveyance of the document, and the reading is performed. It can be seen that this greatly contributed to the improvement of stable conveyance of the original document.

[0022]

As described above, in the ADF 8 having the U-turn path 19, the larger the circular arc shape of the upstream inclined portion 132 and the downstream inclined portion 133 of the reading guide 13 that guides the back side of the document, the larger the circular arc shape. , It is possible to prevent sudden blurring and floating of the document being conveyed.

However, since the upstream side slanted portion 132 and the downstream side slanted portion 133 are the portions that most rub against the original,
When the original is a paper type or a thick paper having a high friction coefficient, and the faster the original is conveyed, the larger the sliding resistance with respect to the original. As a result, there is a problem that the conveyance speed becomes slow due to the sliding resistance, the read image extends in the sub-scanning direction, and in particular, the trailing edge of the original extends significantly from the position where it passes through the pre-reading roller 11.

Further, there has been a problem that the increase in sliding resistance promotes the generation of static electricity, and the static electricity attracts the original document being conveyed, thereby slowing or stopping the original document conveyance speed.

According to the present invention, there is provided a document feeding device which suppresses the deceleration of the conveying speed by reducing the sliding resistance to the document and prevents the read image from extending in the sub-scanning direction, and an image reading device provided with the document feeding device. An image forming apparatus is provided.

According to the present invention, when a sheet-shaped document is fed in an image reading position for reading the image of the document, the document is fed in an obliquely upward direction and discharged in an obliquely upward direction. To prevent the reduction of the conveyance speed by reducing the sliding resistance with the original without compromising the shape of the upstream and downstream inclined parts of the reading guide, the reading image is extended in the sub-scanning direction. An object of the present invention is to provide an original document supply device that is prevented, an image reading device including the original document supply device, and an image forming apparatus.

[0027]

In order to achieve the above-mentioned object, a document feeding device having a document blurring prevention function provides a sheet-shaped document from an obliquely upper position to an image reading position for reading an image of the document. And a document path for guiding the document to be discharged obliquely upward, an upstream side transport means for guiding and transporting the document to the image reading position using the document path, and a document path for guiding the document to the image reading position. And a downstream side transporting means for discharging and transporting from the upstream side transporting means and a side wall for guiding the back side of the document in the document path between the upstream side transporting means and a position facing the image reading position, and the image reading position. The sliding friction reducing means for reducing sliding friction with respect to the back surface of the document is provided at least on one side between the downstream side conveying means and the downstream side conveying means.

The side wall of the document feeder having the document blur prevention function of the present invention has a flat reading guide portion formed at a position facing the image reading position, the upstream side conveying means and the reading guide portion. Formed between the upstream guide means and the downstream guide means, and the upstream guide part formed between the upstream guide means and the downstream guide means. Section, and a downstream side inclined portion which is inclined obliquely upward toward the downstream side conveying means, and at least one of the upstream side inclined portion and the downstream side inclined portion is provided with the sliding friction reducing means. .

The upstream side sloped portion and the downstream side sloped portion provided on the side wall of the original document feeder having the original document blur prevention function of the present invention are formed by flat planes, and the upstream side inclined planes are formed by planes. At least one of the portion and the downstream side inclined portion is provided with the sliding friction reducing means.

The side wall of the document feeding device having the document blur prevention function of the present invention holds the document feeding path in the reading guide portion projecting toward the image reading position at a predetermined distance. It is provided with a gap maintaining protrusion.

The side wall of the document feeder having the document blur prevention function of the present invention is formed on a guide member forming one side of the document path.

The sliding friction reducing means of the document feeder having the document blur prevention function of the present invention is a protrusion.

The guide member of the document feeding apparatus having the document blur prevention function of the present invention is a resin molded product in which at least the sliding friction reducing means is integrally molded out of the gap holding projection and the sliding friction reducing means. Is.

The sliding friction reducing means of the document feeding apparatus having the document blur prevention function of the present invention is a rib provided so as to project along the document conveying direction.

The ribs of the document feeder having the document blur prevention function of the present invention are provided with a plurality of protrusions in a direction intersecting with the conveying direction of the document.

The sliding friction reducing means of the document feeding apparatus having the document blur prevention function of the present invention is a low friction member which is curved in the document path and protrudes from the wall surface and has a smaller frictional resistance than the side wall. Is.

The low-friction member of the document feeder having the document blur prevention function of the present invention is made of metal.

The sliding friction reducing means of the document feeder having the document blur prevention function of the present invention is a rotatable rotating body.

A plurality of the rotating bodies of the document feeding apparatus having the document blur prevention function of the present invention are arranged in a direction intersecting with the document conveying direction.

The rotating body of the document feeder having the document blur prevention function of the present invention is made of metal.

In order to achieve the above object, an image reading apparatus of the present invention reads a document supplied to an image reading position by the document feeding device having any one of the document blurring preventing functions. And an image reading unit.

In order to achieve the above object, the image forming apparatus of the present invention reads a document supplied to an image reading position by the document supply device having any one of the document blur prevention functions described above. The image reading unit includes an image reading unit and an image forming unit that forms the image information read by the image reading unit on a recording medium.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION In the following, an example of a document feeding apparatus according to an embodiment of the present invention, an image reading apparatus including the document feeding apparatus, and an image forming apparatus including the document feeding apparatus and the image reading apparatus will be described. A copying machine will be described with reference to the drawings.

FIG. 1 is a schematic front sectional view of a copying machine which is an image forming apparatus equipped with an automatic document feeder (ADF) which is a document feeder according to the first embodiment of the present invention and an image reading device. FIG. 2 is a schematic front sectional view showing a main part of the image reading apparatus. FIG. 3 is a cross-sectional view taken along the document feeding direction showing a main part of the automatic document feeder which is the document feeder of the first embodiment of the present invention. FIG. 4 is an enlarged view of the vicinity of the reading point of the ADF of the first embodiment. FIG. 5 is a perspective view of a reading guide attached to the ADF of the first embodiment. In addition, in FIG. 1 to FIG.
2, those having the same members or the same functions as those in FIG. 13 are denoted by the same reference numerals, and the description thereof will be omitted.

(Copier) A copier 100 which is an image forming apparatus will be described with reference to FIG. The copying machine 100 is formed by stacking an image reading device (hereinafter referred to as “scanner unit”) 90 and an automatic document feeder (hereinafter referred to as “ADF”) 31 on the laser scanner 113. ing.

Laser scanner 113 for image writing
Processes the image read by the scanner unit 90 and applies laser light to the photosensitive drum 108 according to a recording signal.
And a latent image is formed on the photosensitive drum 108. The latent image becomes a toner image by the toner supplied from a toner supply device (not shown). The cassette 102 contains a recording medium P such as paper or a sheet film. The pickup roller 103 takes out the recording medium P from the cassette 102 according to the recording signal. The transport roller 104 and the separation roller 105 send the recording medium P one by one to the registration roller pair 106 and 107. Registration roller pair 10
6 and 107, when the recording medium P is skewed, the straightening is performed. Then, the registration roller pair 106, 10
Reference numeral 7 supplies the original document to a position facing the photoconductor drum 108. The transfer device 109 transfers the toner image formed on the photosensitive drum 108 to the recording medium P. Then, the fixing device 110 fixes the toner image on the recording medium P to which the toner image has been transferred. The discharge roller pair 111, 111 provided on the downstream side of the fixing device 110 discharges the recording medium P, on which the image is fixed by the fixing device 110, to the paper discharge tray 112.

(Image Reading Device (Scanner Unit)) The scanner unit 90 will be described with reference to FIGS. On the upper surface of the scanner section 90, a document table glass 62 for receiving the document G for reading the document G in a flat state is mounted.
An ADF 31 is mounted on the upper part of the scanner unit 90 so as to be openable and closable with respect to the platen glass. ADF31 has A
When the DF 31 is closed, the original G is pressed against the original glass 62.

The scanner unit 90 is equipped with the image reading carriage 50 which is movable along the guide shaft 57. The image reading carriage 50 is configured such that the rotational force of a motor (not shown) is transmitted through the drive gear 58, the drive pulleys 59 and 60, and the drive belt 61 to reciprocate laterally. The image reading carriage 50 includes a lamp 51 for irradiating the document G and reflecting mirrors 52, 53, 5
4, a lens 55, and a photoelectric conversion element 56 are mounted. The image of the document G illuminated by the lamp 51 is guided to the photoelectric conversion element 56 via the reflection mirrors 52, 53, 54 and the lens 55.

The scanner section 90 scans the original G placed on the original table glass 62 by the user with the image reading carriage 50.
Can be moved and read. That is, the scanner unit 90 is capable of fixed reading. In addition, the scanner unit 90 uses the ADF 31.
The original G supplied by the original glass table 62 and passing through the reading point (image reading position) Q can be read while the image reading carriage 50 is moved to a predetermined reading point Q position and stopped. It is like this. That is, the scanner unit 90
It is designed to be able to be scanned.

The automatic document feeder, which is the document feeder of the first to third embodiments of the present invention, can automatically and continuously feed the document bundle set on the document tray 1 to the scanner section 90. It has become. Further, the user can supply the originals fed one by one to the original tray 1.

(The automatic document feeder (AD of the first embodiment
F)) Based on FIGS. 3 to 5, the ADF of the first embodiment
31 will be described. In the ADF 31 of the first embodiment, the same members and the same functions as those in FIGS. 12 and 13 are indicated by the same reference numerals, and the description thereof will be omitted.

The reading guide (guide member) 20 feeds the document G to the reading point Q from an obliquely upper position and guides the document G at an obliquely upper position to eject the original G.
Acts as a side wall that guides the back of the. The reading guide 20 is rotatably provided on the main body 34 of the ADF 31 by a rotation fulcrum 204. The document path 25 forms a U-turn path.

Reading point Q of the reading guide 20
A flat surface portion (guide portion) 201, which is a flat surface parallel to the platen glass 62, is formed on the surface facing the platen glass 62. An upstream side inclined portion 202 is formed so as to extend upward from the plane portion 201 in the upstream direction. The upstream side inclined portion 202 is
The upstream flat surface portion 202b formed in a flat surface and the upstream side rib portion (sliding friction reducing means, rib) 202a formed in the upstream flat surface portion 202b in a rib shape. Figure 5
As shown in FIG. 5, the upstream rib portion 202a is provided on both sides of the two pre-reading rollers 11 and 11 and substantially in the center of the two pre-reading rollers 11 and 11, a total of five, which are orthogonal to the document conveying direction. It is arranged in the direction of. Upstream flat portion 20
2b is one step lower than the location where the upstream rib portion 202a is arranged. The pre-reading roller (upstream conveying means) 11 faces a pressure roller (upstream conveying means) 12.

Therefore, the upstream side inclined portion 202 has an uneven shape in the direction orthogonal to the document conveying direction. The cross-sectional shape of the upstream rib 202a is the same as that of the reading guide 13 shown in FIGS.
Is formed in the same shape as the upstream side inclined portion 132.

On the surface 202c of the upstream side rib portion 202a for guiding the rear surface of the document, the rear end of the document is the pre-reading roller 11.
In order to prevent fluttering at the moment when the document passes through, it is formed in an arc surface large enough to hold the rear end of the document, and the gap between the reading guide 20 and the guide mylar 14 is narrowed.

Further, by forming the upstream side inclined portion 202 into a shape in which the upstream side rib portion 202a is projectingly provided on the upstream side flat portion 202b, the sliding area of the reading guide 20 with respect to the conveyed original document is reduced and the original document is reduced. Since it is possible to suppress the sliding resistance of the document, it is possible to prevent the document conveyance speed from decreasing.

On the other hand, the plane portion 201 of the reading guide 20
On the downstream side, a downstream inclined portion 203 is formed so as to extend upward from the flat portion 201 in the upstream direction. The downstream side inclined portion 203 is a downstream side flat surface portion 203 formed of a flat surface.
b, and a downstream rib portion (sliding friction reducing means, rib) 203a formed in a rib shape on the downstream flat surface portion 203b. As shown in FIG. 5, the downstream rib portion 203a
Are orthogonal to the document transport direction, a total of three at the same position as the two paper discharge rollers (downstream side transporting means) 15 and 15 and at the position substantially in the center of the two paper discharge rollers 15 and 15. It is arranged in the direction. The downstream plane portion 203b is one step lower than the place where the downstream rib portion 203a is not arranged. As shown in FIG. 3, the paper discharge roller 15 faces a paper discharge pressure roller (downstream side conveyance unit) 16.

Therefore, the downstream side inclined portion 203 has an uneven shape in the direction orthogonal to the document conveying direction. The cross-sectional shape of the downstream side rib portion 203a is the same as that of the reading guide 1 shown in FIGS.
3 has the same shape as the downstream inclined portion 133.

A surface 203c of the downstream side rib 203a for guiding the rear surface of the original is formed in a large arc shape so as to extend the downstream flat surface 203b, and the rear end of the original has passed through the pre-reading roller 11. Afterward, the original document, which is about to rise due to the waist of the original document, is provided with a large arcuate shape to give the original document a downward waist to prevent the original document from rising.

Further, by forming the downstream side inclined portion 203 into a shape in which the downstream side rib portion 203a is projected on the downstream side plane portion 203b, the sliding area of the reading guide 20 with respect to the conveyed original document is reduced, and the original document is reduced. The sliding resistance of can be suppressed.

As described above, the AD of the first embodiment
The F31 forms the upstream inclined portion 202 that extends upstream from the flat portion 201 of the reading guide 20 and the downstream inclined portion 202 that extends downstream from the flat portion 201 into rib shapes to prevent blurring and floating of the document. At the same time suppressing
It is possible to suppress the reduction of the document conveying speed due to the sliding resistance and prevent the read image from extending in the sub-scanning direction.

Although the upstream rib portion 202a, the downstream rib portion 203a, and the reading guide 20 in the ADF 31 of the first embodiment are integrally formed of resin, the material, the number of ribs, and The thickness and the arrangement position in the direction orthogonal to the conveying direction are not limited to this.

Further, the upstream rib portion 202a and the downstream rib portion 203a do not necessarily have to be provided both, but only one may be provided. Also in this case, the same effect as described above can be obtained. Further, in the present embodiment, the upstream side inclined portion 20
2 and the downstream slanted portion 203, in order to reduce the sliding area with the document, the flat surface (upstream flat surface portion 202b) except for the upstream rib portion 202a and the downstream rib 203a (sliding friction reducing means, ribs). However, it does not necessarily have to be a flat surface, and even if it is a curved surface as long as it is a step lower than the rib and reduces the sliding area with the original,
It may be a groove or a through hole.

(The automatic document feeder (AD of the second embodiment
F)) Based on FIGS. 6 to 8, the ADF of the second embodiment
32 will be described. In the ADF 32 of the second embodiment, description of the same members and the same functions as those of the conventional example described in the section of the related art and the ADF of the first embodiment will be omitted. Further, the image forming apparatus and the image reading apparatus in which the ADF 32 of the second embodiment is mounted are the first
The embodiment is the same as the embodiment described above, and the description thereof is omitted here.

FIG. 6 is an enlarged view of the vicinity of the reading point of the ADF 32 of the second embodiment. FIG. 7 is a perspective view of a reading guide attached to the ADF of the second embodiment. FIG. 8 is an enlarged view showing the configuration of the rib portion of the reading guide.

The reading guide (guide member) 21 of the second embodiment also has a side wall that guides the rear surface of the original G in the original path 25 that supplies the original G to the reading point Q from the obliquely upper side and guides the obliquely upward discharge. Plays the role of. The reading guide 21 is rotatably provided on the main body of the ADF 32 by a rotation fulcrum 214. Document path 25
Form a U-turn path.

Similarly to the reading guide 20 of the first embodiment, the reading guide 21 of the second embodiment also has an upstream sloped portion 212 which extends upward in the upstream direction from a flat surface portion (guide portion) 211, and a flat surface portion. The downstream side inclined portion 213 extending upward from 211 in the downstream side direction is connected to the upstream side rib portion 21.
2a and the downstream rib portion 213a form a rib structure.

As shown in FIG. 7, the upstream rib portion 212a
The downstream rib portion 213a and the downstream rib portion 213a are arranged at the same positions as the upstream rib portion 202a and the downstream rib portion 203a of the first embodiment, and the upstream flat surface portion 212b and the downstream flat surface portion 2 are arranged.
It is projected on 13b. The upstream flat surface portion 212b and the downstream flat surface portion 213b are flat surface portions formed by being lowered by one step from the upstream rib portion 212a and the downstream rib portion 213a.

The reading guide 21 of the second embodiment is made of a resin, and the upstream side rib 212a and the downstream side rib 213a have a conductive sheet having a lower friction coefficient than that of the resin on the paper-passing surfaces thereof. (Sliding friction reducing means, low friction member, metal plate) 22a, 22b is featured.

As shown in FIG. 8, the upstream ribs 212a,
A groove 35 is formed in the downstream rib 213a, and the aluminum plates 22a and 22b are fixed to the groove 35 with an adhesive or the like. As described above, by providing the reading guide 21 with the aluminum plate 22, the sliding resistance can be further reduced as compared with the effect obtained by the reading guide 20 according to the first embodiment, and the document feeding speed can be improved. When it becomes faster, the original and the reading guide 2
The static electricity generated by friction with 1 can be released, and it is possible to prevent the document speed from being lowered due to the static electricity adhering the document to the reading guide 21.

The upstream rib portion 212a and the downstream rib portion 21
3a has a sectional shape of the upstream rib portion 202 of the first embodiment.
a and the downstream rib portion 203a are formed in substantially the same shape and have aluminum plates 22a and 22b.

Therefore, the surface 22c of the aluminum plate 22a provided on the upstream rib portion 212a for guiding the rear surface of the document suppresses the fluttering of the document at the moment when the trailing edge of the document leaves the pre-reading roller 11, and the downstream rib A surface 22c of the aluminum plate 22b provided on the portion 213a for guiding the rear surface of the original has a shape sufficient to prevent the original from rising.

In this embodiment, the reading guide 2
An aluminum plate was provided on the rib sheet passing surface of No. 1, but it is not limited to the aluminum plate as long as it has a low friction coefficient and is conductive. Further, in the present embodiment, the grooves 35 are formed on the upstream ribs 212a and the downstream ribs 213a formed of resin, and the aluminum plates 22a and 22b are fixed to the grooves 35, but the rib sheet passing surface has low friction. Any member or conductive member may be used, and for example, the rib itself may be formed of metal and fixed to the reading guide 21.

The upstream rib portion 212a provided with the aluminum plate 22a and the downstream rib portion 21 provided with the aluminum plate 22b.
It is not always necessary to provide both of 3a, but only one may be provided. Also in this case, the same effect as described above can be obtained.

(Automatic Document Feeding Device (AD
F)) A of the third embodiment based on FIGS. 9 to 11.
The DF33 will be described. The ADF 33 of the third embodiment
First, the conventional example described in the section of the prior art, and the first
Description of the same members and functions as those of the ADF of the embodiment will be omitted. In addition, the ADF3 of the third embodiment
The image forming apparatus and the image reading apparatus in which the No. 3 is mounted are the same as those in the first embodiment, and the description thereof is omitted here.

FIG. 9 is an enlarged view of the vicinity of the reading point of the ADF of the third embodiment. FIG. 10 is a perspective view of a reading guide attached to the ADF of the third embodiment.
FIG. 11 is an enlarged view showing a configuration in which rollers are provided in the reading guide.

The reading guide (guide member) 23 of the second embodiment also has a side wall that guides the rear surface of the original G in the original path 25 that supplies the original G to the reading point Q from the obliquely upper side and guides the obliquely upward discharge. Plays the role of. The reading guide 23 is rotatably provided on the main body of the ADF 33 by a rotation fulcrum 234. Document path 25
Form a U-turn path.

The reading guide 23 according to the third embodiment has a flat surface portion 23 and an upstream flat surface portion 232b of an upstream slanting portion 232 that extends upward from the flat surface portion (guide portion) 231.
A plurality of holes 236a and 236b are formed in the direction perpendicular to the document conveying direction in each of the downstream flat surface portion 233b of the downstream side inclined portion 233 that extends upward from 1 to the downstream side. In the hole 236a of the upstream side inclined portion 232,
A roller (sliding friction reducing means, rotating body) 24a protruding from the hole 236a toward the sheet passing surface is rotatably provided. The hole 236b of the downstream side inclined portion 233 has a hole 23
Rollers (sliding friction reducing means, rotating body) 24b projecting from 6b toward the paper passing surface are rotatably provided. Around 2
4a and 24b are made of resin or metal. When it is made of resin, sliding resistance can be reduced. When it is made of metal, the sliding resistance can be reduced and static electricity can be released.

Reading guide 2 of the first and second embodiments
Upstream rib portions 202a and 212 provided on
a, and is provided at the same position as the downstream rib portions 203a and 213a. The maximum amount of protrusion of the rollers 24a and 24b is the same as the amount of protrusion of the upstream rib 202a and the downstream rib 203a projecting from the reading guide 20 of the first embodiment, as shown by the thin line in FIG. .

That is, the roller 24a arranged on the upstream side inclined portion 232 suppresses the fluttering of the original at the moment when the rear end of the original passes through the pre-reading roller 11, and the downstream side inclined portion 233.
The rollers 24b arranged in the above are arranged so as to have a protrusion amount sufficient to suppress the lifting of the document.

Further, as shown in FIG. 11, the rollers 24a,
24b denotes an upstream bearing portion 232a and a downstream bearing portion 2
Since it is rotatably supported by the shaft 33a,
When a document passes, it rotates with the document being conveyed,
The sliding resistance can be suppressed without impairing the stable conveyance of the document near the reading point Q.

The reading guide 20 of each of the above embodiments,
Abutting protrusions (gap holding protrusions) 205, 215, are formed on both ends of the flat portions 201, 211, 231 of the 21, 23.
235 is projected downward. This bumping protrusion 20
5,215,235 abut the guide mylar 14,
A minute gap is created between the reading guides 20, 21, 23 and the guide mylar 14. That is, the document transport paths in the flat surface portions (reading guide portions) 201, 211, 231 are held at a predetermined interval.

[0083]

According to the document feeding apparatus of the present invention, a sheet-shaped document is guided to the image reading position where the image of the document is read from a diagonally upper direction and is guided obliquely upward to guide the back side of the document. A side wall between the upstream side conveying means and a position facing the image reading position;
At least one of the position between the image reading position and the downstream-side conveying means is provided with a sliding friction reducing means for reducing sliding friction with respect to the back surface of the document, so that the sliding resistance between the document path and the document is suppressed. Even when a document with a high coefficient of friction is conveyed or the conveyance speed becomes faster, the blurring and floating of the document being read can be suppressed and the decrease in the conveyance speed due to sliding resistance can be suppressed. It is possible to prevent the read image from extending in the sub-scanning direction.

According to the document feeder of the present invention, a sheet-shaped document is provided on the side wall for guiding the back side of the document in the document path for feeding and guiding the sheet from the diagonally upper position to the image reading position for reading the image of the document. Since the protrusions are formed on the upstream side inclined portion and the downstream side inclined portion, the sliding area between the original document path and the original document can be reduced to suppress the sliding resistance, and the original document having a high friction coefficient is conveyed. In this case, even if the conveyance speed becomes high, the blurring and floating of the document being read can be suppressed, and at the same time, the reduction of the conveyance speed due to sliding resistance can be suppressed to prevent the read image from extending in the sub-scanning direction. be able to.

Since the image reading apparatus of the present invention is equipped with the document feeding apparatus capable of suppressing the blurring of the document and preventing the read image from extending in the sub-operation direction, the document can be reliably and accurately read. Can be read.

Since the image forming apparatus of the present invention is equipped with the image reading apparatus capable of reading the original reliably and accurately, the image read by the image reading apparatus can be formed on the recording material with good quality.

[Brief description of drawings]

FIG. 1 is a schematic front sectional view of a copying machine which is an image forming apparatus including an automatic document feeder (ADF) which is a document feeder according to a first embodiment of the present invention and an image reading device.

FIG. 2 is a schematic front sectional view showing a main part of the image reading apparatus according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along the document conveyance direction showing a main part of an automatic document feeder which is the document feeder of the first embodiment of the present invention.

FIG. 4 is a schematic enlarged view around a reading position in the automatic document feeder which is the document feeder of the first embodiment of the invention.

FIG. 5 is a perspective view of a reading guide attached to the automatic document feeder, which is the document feeder of the first embodiment of the present invention.

FIG. 6 is a schematic enlarged view around an image reading position in an automatic document feeder which is a document feeder of a second embodiment of the invention.

FIG. 7 is a perspective view of a reading guide attached to an automatic document feeder, which is a document feeder according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a rib portion provided on a reading guide mounted on an automatic document feeder which is a document feeder according to a second embodiment of the present invention.

FIG. 9 is a schematic enlarged view of the vicinity of a reading position in an automatic document feeder, which is a document feeder according to a third embodiment of the present invention.

FIG. 10 is a perspective view of a reading guide attached to an automatic document feeder, which is a document feeder according to a third embodiment of the present invention.

FIG. 11 is a perspective view of the vicinity of rollers provided in a reading guide in an automatic document feeder that is a document feeder according to a third embodiment of the present invention.

FIG. 12 is a front sectional view showing a schematic configuration of a copying machine which is an image forming apparatus equipped with a conventional automatic document feeder.

FIG. 13 is an enlarged sectional view of a main part of a conventional automatic document feeder.

14 is a cross-sectional view taken along the line AA in FIG.

FIG. 15 is a schematic view showing a document conveyance state in a conventional automatic document feeder.

FIG. 16 is a schematic view showing a document conveyance state in another conventional automatic document feeder.

[Explanation of symbols]

Q reading point (image reading position) P recording material G original document 11 pre-reading roller (upstream conveying means) 12 pressure roller (upstream conveying means) 13 reading guide (side wall, guide member) 131 flat surface portion (reading guide portion) 132 upstream side inclined portion 133 downstream side inclined portion 135 projection (gap holding projection portion) 14 guide mylar 15 paper ejection roller (downstream side conveyance means) 16 paper ejection pressure roller (downstream side conveyance means) 20 reading guide (side wall, guide) Member) 201 Flat surface portion (reading guide portion) 202 Upstream side inclined portion 202a Upstream side rib portion (sliding friction reducing means, rib) 202b Upstream side flat portion 202c Surface 203 contacting the back surface of the document 203 Downstream side inclined portion 203a Downstream rib Portion (sliding friction reducing means, rib) 203b downstream flat surface portion 203c surface 205 contacting the back surface of the original Gap holding projection 21) Reading guide (side wall, guide member) 211 Flat surface (reading guide) 212 Upstream inclined portion 212a Upstream rib portion 212b Upstream flat portion 213 Downstream inclined portion 213a Downstream rib portion 213b Downstream side Flat part 215 Protrusion (gap holding protrusion) 22a Aluminum plate (sliding friction reducing means, low friction member,
Metal plate) 22b Aluminum plate (sliding friction reducing means, low friction member,
Metal plate) 22c Surface that contacts the back surface of the document 23 Reading guide (side wall, guide member) 231 Flat portion (reading guide portion) 232 Upstream side inclined portion 232a Upstream side bearing portion 232b Upstream side flat portion 233 Downstream side inclined portion 233a Downstream Side bearing part 233b Downstream flat surface part 235 Projection (gap holding projection part) 24a Roller (sliding friction reducing means, rotating body) 24b Roller (sliding friction reducing means, rotating body) 25 Document path 31 Automatic document feeder (ADF) 32 Automatic Document Feeder (ADF) 33 Automatic Document Feeder (ADF) 90 Scanner Unit 100 Image Forming Device

Continued front page    (72) Inventor Makoto Izumi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 3F101 FA02 FB17 FC05 FD01 FD02                       FE19 LA02 LA05 LB02                 5C062 AA02 AA05 AB02 AB32                 5C072 AA01 DA02 DA04 EA04 LA18                       NA01 XA01

Claims (16)

[Claims] 1. A document path for feeding and guiding a sheet-like document from an obliquely upper position to an image reading position for reading an image of the original document and for discharging and discharging it obliquely upward; A side wall that guides the rear surface of the original in the original path, and upstream conveying means that supplies and conveys the original to the position, and downstream conveying means that guides the original path to discharge and convey the original from the image reading position. Reduces the sliding friction with respect to the back surface of the document at least at one of the upstream side conveying means and the position facing the image reading position, and at least between the image reading position and the downstream side conveying means. An original feeding device having an original blur prevention function, which is provided with a sliding friction reducing means. 2. The side wall is formed between a flat reading guide portion formed at a position facing the image reading position, and between the upstream conveying means and the reading guide portion. It is formed between an upstream side inclined part which is inclined obliquely downward toward the reading guide part, and between the reading guide part and the downstream side conveying means, and is obliquely upward from the reading guide part toward the downstream side conveying means. 2. The original document according to claim 1, further comprising: a downstream side inclined portion that is inclined to the front side; and at least one of the upstream side inclined portion and the downstream side inclined portion includes the sliding friction reducing means. A document feeder with a shake prevention function. 3. The document feeder according to claim 2, wherein the upstream side inclined portion and the downstream side inclined portion are formed by flat planes. 4. The side wall is provided with a gap holding projection portion which is provided on the reading guide portion and projects toward the image reading position to hold a document transport path in the reading guide portion at a predetermined distance. A document feeding device having a document blurring prevention function according to any one of claims 1 to 3. 5. The side wall is formed on a guide member forming one side of the document path.
An original feeding device having an original blur prevention function according to any one of items 1 to 4. 6. The document feeding apparatus with a document blur prevention function according to claim 1, wherein the sliding friction reducing means is a protrusion. 7. The guide member is a resin molded product in which at least the sliding friction reducing means is integrally molded out of the gap holding projection and the sliding friction reducing means. A document feeding device having the document blur prevention function described in [4]. 8. The document shake prevention function according to claim 1, wherein the sliding friction reducing means is a rib that is provided so as to project along the document conveying direction. A document feeder provided. 9. The document feeder according to claim 8, wherein a plurality of the ribs are provided so as to project in a direction intersecting with a transport direction of the document. 10. The sliding friction reducing means is a low-friction member that is curved in the document path and protrudes from the wall surface and has a smaller friction resistance than the side wall. An original document feeder having the original document blur prevention function according to any one of items 1 to 10. 11. The document feeder according to claim 10, wherein the low friction member is made of metal. 12. The document feeding apparatus with a document blur prevention function according to claim 1, wherein the sliding friction reducing means is a rotatable rotating body. 13. The document feeder according to claim 12, wherein a plurality of the rotating bodies are arranged in a direction intersecting with a conveying direction of the document. 14. The document feeder according to claim 12, wherein the rotating body is made of metal. 15. A document feeding device having a document blur prevention function according to claim 1, and an image reading unit for reading a document fed to an image reading position by the document feeding device. An image reading apparatus comprising: 16. A document feeding device having a document blurring prevention function according to claim 1, and an image reading unit for reading a document fed to an image reading position by the document feeding device. An image forming apparatus comprising: an image forming unit that forms image information read by the image reading unit on a recording medium.