JP2004099306A - Automatic document feeder and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader causing no deterioration in an image and carrying facilure by preventing sticking of a flaw and a waste material to a transparent guide member for guiding a document by contacting with the reading surface side of the document, and eliminating generation of static electricity by a transparent film member. <P>SOLUTION: A reading passage of a reading part is composed of a backup guide 45 for guiding the document and the transparent film member 50 arranged between a reading means and the backup guide 45. Projecting parts 52 and 53 extending in the document carrying direction are formed in at least one section of a section reaching a reading position X from carrying-in roller pairs 28 of the transparent film member 50 and a section reaching carrying-out roller pairs 25 from the reading position X. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic document feeder provided in an image reading device or the like, and more particularly, to a document transport mechanism provided with a transparent sheet member for transporting a document to be read.
[0002]
[Prior art]
Conventionally, an image reading apparatus has a mechanism in which a document conveyed by a belt or a roller is stopped on a platen glass and a reading optical system is scanned to read an image. There are generally known two types of a reading optical system for reading a document image, that is, a so-called sheet-through reading method.
[0003]
An automatic document feeder applied to the sheet-through reading method includes a device in which a transparent film member is provided above a platen glass for reading a document, and the document is conveyed along the transparent film member. Reference 1).
[0004]
The transparent film member is disposed between the backup guide and the platen glass, and forms a curved reading path between the backup guide and the backup guide. The reading means of the optical system disposed below the platen glass is configured to read the original image via the platen glass and the transparent film member.
[0005]
[Patent Document 1]
JP-A-63-180650
[Problems to be solved by the invention]
Such a transparent film member is generally formed of a flexible member such as a polyethylene terephthalate sheet (Mylar), and static electricity is easily generated when the document surface comes into sliding contact with the guide surface of the transparent film member. Is attracted to the transparent film member, so that the conveyance speed of the document is slightly changed, causing a problem that the read image is distorted. Further, when a large amount of the static electricity is generated, a conveyance failure occurs.
[0007]
In addition, when the transparent film member passes through several hundreds of originals, the surface of the transparent film member on the original transport surface side is damaged due to friction with the originals. As a result, filth such as paper dust and toner is likely to be generated, and a problem such as a black streak occurs in the read image. In addition, various problems such as poor conveyance due to deterioration of the surface roughness of the document guide surface have occurred.
[0008]
Further, since the transparent film member is formed in a thin sheet shape, it is easily broken or deformed, and its handling is not easy, and a stable document conveying path cannot be formed.
[0009]
In view of the various problems described above, the present invention prevents the guide surface of the transparent film member from being scratched or contaminated, and eliminates the generation of static electricity due to the transparent film member, so that image reading without image deterioration or conveyance failure is achieved. It is intended to provide a device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a curved reading path from a first conveying unit to a second conveying unit is disposed between a guide member for guiding a document and the reading unit and the guide member. And a transparent guide member extending from the first transport means to the reading position on at least one portion of the document guide surface of the guide member, the convex portion extending in the document transport direction.
[0011]
As a result, the area where the document and the document guide surface are in sliding contact with each other is reduced, and the transport load is reduced, and the generation of static electricity is suppressed. Further, since the sliding contact area is small, it is possible to suppress the generation of waste such as paper dust and printing toner of the document. Further, by forming a plurality of protrusions, the strength of the transparent film member is increased, and breakage and deformation can be eliminated.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a view showing an automatic document feeder 2 mounted on an image reading apparatus 1 according to the present invention. Based on FIG. 1, the image reading apparatus 1 according to the present invention and an automatic document provided in the image reading apparatus 1 are shown. The overall configuration of the feeding device 2 will be described.
[0013]
As shown in FIG. 1, the main body of the image reading apparatus 1 irradiates light from a light source 5 such as a lamp via a platen glass 4 onto a conveyed document, and reflects the reflected light by a plurality of mirrors 6 to form a lens. The original image is read by photoelectric conversion by a reading element 8 such as a CCD via the. Here, the image reading apparatus 1 moves a thick document such as a book placed on the platen glass 4 through the platen glass 4 by moving a light source unit including the light source 5 and the mirror 6 in the sub-scanning direction. And a mode for reading the original conveyed above the platen glass 4 by the automatic original feeder with the light source unit stopped at a predetermined reading position.
[0014]
In the automatic document feeder, a paper feed tray 10 on which a plurality of documents can be placed, a paper discharge tray 11 for storing read documents, and a porous member such as a sponge for pressing the platen glass 4 and white paper. A pressing cover 12 made of a film member such as Mylar is provided.
[0015]
The paper feed unit includes a feed roller 21 that can move up and down and comes out of contact with the top document of the document placed on the paper feed tray 10, and a feed roller 22 that feeds the document fed by the feed roller 21. Separating means comprising a separating member 23 for passing only one of the upper documents and preventing the feeding of the second and subsequent documents, and abutting the leading end of the separated and fed original by the separating means. A registration roller pair 24 that is fed downstream after alignment is provided.
[0016]
The feed roller 21, the feed roller 22, and the registration roller pair 24 are drivingly connected to a feed motor (not shown), and the feed roller 21, the feed roller 22 are driven by the forward rotation of the feed motor. Are rotated, and the registration roller pair 24 is rotated by the rotation of the sheet feeding motor in the opposite direction. The rotation of the feed roller 21, the sheet feeding roller 22, and the registration roller pair 24 causes the registration roller pair 24 to rotate. Is guided along the paper feed path 30.
[0017]
The conveyance unit includes a pair of carry-in rollers 28 (first conveyance unit) that conveys the document to the reading position X, a carry-in guide 15 that guides the document from the pair of carry-in rollers 28 toward the reading position X, and reads the document at the reading position X. Pair of discharge rollers 25 (second transport means) for discharging the received document, a discharge guide 16 for guiding the document from the reading position X to the pair of discharge rollers 25, and a hook between the input guide 15 and the discharge guide 16. A transparent film member 50 (guide member) which is passed and forms a curved document reading path on the platen glass side, a platen roller 27 provided between the reading position X and the carry-in roller pair 28 and in contact with the transparent film member 50; A white backup guide 45 (guide member) is disposed downstream of the platen roller 27 and contacts the transparent film member 50.
[0018]
The rollers of the carry-in roller pair 28, the carry-out roller pair 25, and the platen roller 27 are each rotated only in one direction by the transport motor.
[0019]
A discharge roller pair 26 that discharges the original from the discharge roller pair 25 to the discharge tray 11 along the discharge path 31 is disposed in the discharge section. The discharge roller pair 26 is drivingly connected to the above-described transport motor, and rotates in one direction to discharge a document to the discharge tray 11 in the single-sided mode, and outputs the document to the discharge tray 11 in the double-sided mode. Control is performed such that the document is switched back by rotating in the reverse direction with the end portion nipped, and resent to the transport path (reading path) 35 via the circulation path 32.
[0020]
The paper discharge path 31 is provided with a self-weight flapper 41 which is movable upward by the leading edge of the document to be sent to pass the document, and is movable downward when the rear end of the document passes. The paper roller 26 reversely guides the switched back document to the circulation path 32 without any trouble. The flapper 41 is constantly urged downward by an urging spring, and is pushed upward by the leading end of the discharged document when the document is sent to the discharge roller pair 26 along the discharge path 31. When the document is allowed to pass and the document is switched back by the discharge roller pair 26, the document is positioned below and closes the discharge path 31, and the document is guided to the circulation path 32.
[0021]
An empty sensor S1 for detecting that a document is placed on the paper feed tray 10 is provided downstream of the paper feed tray 10 in the document feeding direction. A registration sensor S2 for detecting a portion is provided. Further, a read sensor S3 is provided in front of the reading unit, and a discharge sensor S4 is provided in front of the paper discharge roller pair 26, and these sensors detect the end of the fed document.
[0022]
Each of the sensors S1 to S4 is connected to control means including a CPU and the like for controlling the conveyance of the original, and the above-described paper feed motor and conveyance motor are controlled based on a detection signal from each sensor. Each operation of feeding, transporting, and discharging a document is performed.
[0023]
FIG. 2 is a cross-sectional view showing the reading unit 20 provided in the transport unit, FIG. 3 is a perspective view showing the configuration of the transparent film member 50, the carry-in guide 15 and the carry-out guide 16, and FIG. FIG. 4B is a plan view, FIG. 4B is a cross-sectional view of the transparent film member 50 taken along line A, and FIG. 5 is a diagram illustrating a tension applying mechanism for applying tension to the transparent film member 50.
[0024]
The configuration of the reading unit 20 will be described in detail with reference to FIGS.
[0025]
As shown in FIG. 2, the reading unit 20 provided in the transport unit includes the above-described carry-in guide 15, carry-out guide 16, transparent film member 50, platen roller 27, and backup guide 45.
[0026]
The carry-in guide 15, the carry-out guide 16, the transparent film member 50, and the tension applying member 55 described later constitute an integrated reading guide unit 60 as shown in FIG. 3, and the reading guide unit 60 is attached to the apparatus frame. It is detachably attached to it.
[0027]
The carry-in guide 15 and the carry-out guide 16 are integrally formed of resin to form a skeleton of the reading guide unit 60, and an opening for reading a document is formed at the center thereof. A transparent film member 50 and a tension applying member 55 are attached to the carry-in guide 15 and the carry-out guide 16 which are integrally formed of resin.
[0028]
Furthermore, white film members 46 and 47 disposed between the transparent film member 50 and the platen glass 4 are attached to the carry-in guide 15 and the carry-out guide 16. The white film members 46 and 47 are provided before and after the reading position X in the document conveying direction, and a good image can be obtained even when a thin paper document manually placed on the platen glass 4 transmits light of the light source 5. .
[0029]
As shown in FIGS. 3 and 4A, the transparent film member 50 has a flat portion 51 formed around the reading position X where the platen roller 27 and the backup guide 45 contact each other. On the side portion, a convex portion 52 extending in the document transport direction is formed. Further, a convex portion 53 extending in the document conveying direction is formed on a downstream portion of the flat portion 51.
[0030]
A plurality of convex portions 52 and 53 formed before and after the flat surface portion 51 having a flat surface are formed at predetermined intervals in a document width direction orthogonal to the document conveyance direction. The document conveyed to the reading position X is guided while sliding on the plurality of convex portions 52, and the document passing through the reading position X is guided by the discharge roller pair 25 while sliding on the plurality of convex portions 53 on the downstream side. You. In this embodiment, the heights of the projections 52 and 53 are set to about 0.5 mm.
[0031]
The upstream end of the convex portion 52 between the carry-in roller pair 28 and the flat portion 51 extends to near the nip position of the carry-in roller pair 28. As a result, the trailing edge of the document can be smoothly pulled out from the nip position of the pair of carry-in rollers 28, and the shock when the trailing edge of the document falls out of the nip position of the pair of carry-in rollers 28 can be reduced to reduce the blur of the document. I do.
[0032]
The downstream end of the convex portion 52 is formed so that the amount of projection gradually becomes smaller in the document conveying direction, and the front end thereof is gently inclined so as to be continuous with the flat portion 51.
[0033]
The convex portion 53 between the flat portion 51 and the discharge roller pair 25 is formed such that its upstream end gradually increases in the document conveying direction, and its tip is continuous with the flat portion 51. It is gently inclined to be. That is, as shown in FIG. 2, the projections 52 and 53 have no steps between the projections 52 and 53, and the projections are displaced so as to form a curved path, so that the original is smoothly transported. ing. In particular, the convex portion 53 between the flat portion 51 and the carry-out roller pair 25 has a small contact area with the document, so that when the document is scooped up, the document blur caused by the leading edge of the document hitting the guide surface is reduced. Can be.
[0034]
As described above, the peripheral portion of the transparent film member 50 at the reading position X is a flat surface, and a plurality of convex portions 52 and 53 are formed on the upstream side and the downstream side of the flat surface portion 51 so that the document is slid and guided. As a result, the area in which the document and the document guide surface are in sliding contact with each other is reduced, the transport load is reduced, and the generation of static electricity is suppressed. Further, since the sliding contact area is small, it is possible to suppress the generation of waste such as paper dust and printing toner of the document. Further, by forming a plurality of protrusions, the strength of the transparent film member is increased, and breakage and deformation can be eliminated.
[0035]
In addition, the convex portions 52 and 53 of this embodiment are formed in a semi-circular shape that is gently raised as shown in FIG. This prevents the document from being rubbed and damaging the document, and has no corners, so that maintenance becomes easy.
[0036]
Further, in the present embodiment, a scratch-resistant coating is applied to the original guide surface side of the transparent film member 50. This scratch-resistant coating improves the abrasion of the guide surface of the transparent film member 50 by coating a compound such as an organic silane, and makes it difficult for scratches or the like to be formed. Thereby, a better image can be obtained, and the frequency of maintenance of the transparent film member 50 can be reduced.
[0037]
In the above embodiment, the convex portions 52, 53 formed before and after the plane portion 51 in the document conveying direction are formed as one raised arc-shaped convex portion extending in the conveying direction, and are separated by a predetermined distance in the document width direction. Although a plurality of protrusions are formed, a plurality of protrusions may be formed in each of the document conveying direction and the document width direction as shown in FIG. In the second embodiment shown in FIG. 6, the end portions of the adjacent convex portions 72 and 73 in the document width direction are formed so as to partially overlap each other. That is, a plurality of convex portions are formed in a staggered manner.
[0038]
In this way, by forming a plurality of convex portions in a staggered manner, it is possible to prevent only a specific portion of the document surface from slidingly contacting the convex portions. As a result, the document is not stressed excessively, and document damage is minimized.
[0039]
The transparent film member 50 has a plurality of mounting holes 50d at one end on the upstream side in the document conveying direction, and the mounting holes 50d are engaged with the projections 50a formed as fixing portions on the carry-in guide 15. Thus, the transparent film member 50 is fixedly supported. Further, the other end on the downstream side is formed with a plurality of tongues 50b and 50c which are divided into a plurality of IDs. One of the tongue portions 50b of the adjacent tongue portions 50b and 50c which are divided in a blind shape and extend in a free state on the document guide surface side of the carry-out guide 16. The other tongue portion 50c extends to the rear side of the carry-out guide 16, and a mounting hole 50f provided at the tip thereof is engaged with a projection 55a formed as a support portion on a tension applying member 55 described later. .
[0040]
The transparent film member 50 attached as described above forms a transport path 35 that is curved from the document guide surface of the carry-in guide 15 to the document guide surface of the carry-out guide 16, and the elastic force of the platen roller 27 It is pressed against the peripheral surface.
[0041]
A predetermined space (0.5 mm to 1.0 mm) that allows the transparent film member 50 to swing downward is secured between the platen glass 4 and the transparent film member 50. This space allows the original entering between the platen roller 27 and the transparent film member 50 to displace the transparent film member 50 toward the platen glass 4. As a result, even if the platen roller 27 is fixed, the document can smoothly pass through the document transport path.
[0042]
Next, the tension applying member 55 will be described with reference to FIG. 5. The tension applying member 55 engages with the mounting hole 50 f of the tongue 50 c of the transparent film member 50 to fix and support the transparent film member 50, An arm portion 55b having a shaft support hole for engaging a pin formed on the side of the skeleton of the reading guide unit is formed.
[0043]
Further, between the side of the skeleton of the reading guide unit 60 and the arm 55b, the tension applying member 55 is rotated in the document conveying direction with the pivot shaft (rotation axis) 56a of the side of the reading guide unit as a fulcrum. A biasing torsion coil spring 56 is mounted.
[0044]
One end of the torsion coil spring 56 is attached to the arm portion 55b of the tension applying member 55, and the other end is attached to the side of the reading guide unit 60. A tension is applied to the member 50.
[0045]
Here, the transparent film member 50 is placed between the platen roller 27 contacting the transparent film member 50 and the upstream end of the unloading guide 16 contacting the tongue 50c of the transparent film member 50 by applying tension. The slack is eliminated, and the space between the platen roller 27 and the carry-out guide 16 is made substantially parallel.
[0046]
Even if the thickness of the original to be read is different, the transparent film member 50 is displaced by the elastic force of the transparent film member 50 and the tension adjusting function of the tension applying member 55 so that the surface of the transparent film member 50 is displaced toward the platen glass 4 side. It is pressed against the peripheral surface of the roller 27. As a result, the document is stably conveyed without being jammed at the reading position and the speed and direction of the document are not blurred.
[0047]
Here, the attachment / detachment configuration of the reading guide unit 60 will be described. A key-shaped holding portion 63 for attaching the reading guide unit 60 to the apparatus frame is formed on a side portion of the reading guide unit 60. The holding portion 63 is engaged with a concave portion formed in the apparatus frame to hold the reading guide unit 60.
[0048]
The holding portion 63 is made of resin, and can be easily disengaged from the device frame concave portion and the projecting portion 63 by applying a pressing force to bend.
[0049]
Further, a notch 62 of the reading guide unit 60 is formed, and the notch 62 engages with a pin formed on the apparatus frame to rotatably support the reading guide unit 60.
[0050]
That is, in the present embodiment, the holding unit 63 of the reading guide unit 60 is bent to release the holding, and the reading guide unit 60 is moved downward along the notch 62 after the holding unit 63 is rotated around the pin of the apparatus frame. The reading guide unit 60 is removed from the apparatus frame by pulling.
[0051]
Here, the carry-in guide 15, the carry-out guide 16, the transparent film member 50, and the tension applying member 55 described below constitute an integrated reading guide unit 60, and this reading guide unit 60 is detachably attached to the apparatus frame. Therefore, maintenance work such as replacement and cleaning of the transparent film member and the white guide can be easily and reliably performed in a short time without damaging the transparent film member. In addition, maintenance such as wiping of dirt can be performed while the reading guide unit 60 is rotated by a predetermined angle.
[0052]
In the above embodiment, the original is conveyed by the carry-in roller pair 28 and the carry-out roller pair 25, and is passed through the reading unit 20, but a large-diameter roller is disposed at a position facing the original reading position. Alternatively, a pinch roller that presses the upstream and downstream sides of the reading position of the large-diameter roller may be provided to convey the document.
[0053]
As described above, in the present embodiment, a reading path for reading a document includes a guide member for guiding the document, and a transparent guide member disposed between the reading unit and the guide member. Documents are conveyed to at least one of a section from the first conveying means provided on the loading side of the reading section to the reading position and a section from the reading position to the second conveying means provided on the carrying side of the reading section. The convex portion extending in the direction eliminates the generation of static electricity due to the transparent film member, and prevents the generation of dirt attached to the transparent guide member that guides the original when the reading surface side of the original comes into contact with the original. Transport errors can be eliminated.
[0054]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an overall configuration of an image reading apparatus and an automatic document feeder according to the present invention.
FIG. 2 is a cross-sectional view illustrating a reading unit of the automatic document feeder.
FIG. 3 is a perspective view illustrating a configuration of a reading guide unit.
FIG. 4 is a plan view showing a transparent film member, and a cross-sectional view taken along A.
FIG. 5 is a sectional view showing a tension applying mechanism.
FIG. 6 is a plan view of a transparent film member showing another embodiment.
[Explanation of symbols]
Reference Signs List 1 image reading device 2 automatic document feeder 15 carry-in guide 16 carry-out guide 20 reading unit 25 carry-out roller (second carrying means)
27 Platen roller 28 Loading roller pair (first transporting means)
35 Transport path (reading path)
45 Backup guide (guide member)
46 White film member 47 White film member 50 Transparent film member (guide member)
51 flat part 52 convex part 53 convex part 60 reading guide unit

Claims (10)

A reading unit having a reading position for reading a document, first transport means provided upstream of the reading unit for loading the document into the reading unit, and a document provided downstream of the reading unit for reading the document. An automatic document feeder comprising: a second transport unit that carries out of the reading unit; and a curved reading path that extends from the first transport unit to the second transport unit.
The reading path is configured by a guide member for guiding a document, and a transparent guide member disposed between the reading unit and the guide member,
A convex portion is formed in at least a part of the document guide surface of the guide member from the first transport means to the reading position in the transport direction, and the document is slidably contacted with the convex portion to guide the document. Automatic document feeder. A reading unit having a reading position for reading a document, first transport means provided upstream of the reading unit for loading the document into the reading unit, and a document provided downstream of the reading unit for reading the document. An automatic document feeder comprising: a second transport unit that carries out of the reading unit; and a curved reading path that extends from the first transport unit to the second transport unit.
The reading path is configured by a guide member for guiding a document, and a transparent guide member disposed between the reading unit and the guide member,
An automatic document feeder, wherein a convex portion is formed on at least a part of a document guide surface of the guide member from the reading position to the second transport means, and the document is slidably contacted with the convex portion to guide the document. apparatus. A reading unit having a reading position for reading a document, first transport means provided upstream of the reading unit for loading the document into the reading unit, and a document provided downstream of the reading unit for reading the document. An automatic document feeder comprising: a second transport unit that carries out of the reading unit; and a curved reading path that extends from the first transport unit to the second transport unit.
The reading path is configured by a guide member for guiding a document, and a transparent guide member disposed between the reading unit and the guide member,
At least one part of the document guide surface of the guide member from the first transport means to the reading position and at least one part of the document guide surface of the guide member from the read position to the second transport means. An automatic document feeder, which forms a portion and guides the document by sliding it on the convex portion. The automatic document according to any one of claims 1 to 3, wherein the guide member has a flat portion formed on a document guide surface facing the reading position, the flat portion extending in a direction orthogonal to a document conveyance direction. Feeder. The automatic document feeder according to any one of claims 1 to 4, wherein a plurality of the convex portions of the document guide surface are formed at intervals in a direction orthogonal to a document transport direction. 6. The automatic document feeder according to claim 5, wherein the convex portion of the document guide surface extends in a document conveying direction. 5. The automatic document feeder according to claim 4, wherein the guide member is movably provided so as to press a document conveyed by the conveyance unit against a flat portion of the guide member. 6. The automatic document feeder according to any one of claims 1 to 7, wherein the guide member is a sheet-like film member that forms the reading path curved toward the reading unit. The automatic document feeder according to any one of claims 1 to 8, wherein a scratch resistant coating is applied to a document guide surface side of the guide member. An image reading apparatus comprising: the automatic document feeder according to claim 1; and reading means for reading a document conveyed along the reading path at the reading position.

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