JP2002359725A - Double-sided original reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-sided original reader that can prevent optical interference between a plurality of original read sections without making the structure of an original carrying path complicated and can easily be downsized. SOLUTION: Light sources 50, 81, a CCD 15 acting like a light receiving section and an image sensor 83 are respectively provided to 1st and 2nd read sections 10, 32 placed to an upper-stream side carrying path section 33b extended from a curved carrying path 102 toward an upper-stream in an original carrying direction nearly in a planar shape and to a downstream side carrying path section 33c extended toward a downstream in the original carrying direction nearly in a planar shape. Then the 2nd read section comprises a unmagnification optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided document reading apparatus for reversing a document and reading images on both sides of the document.

[0002]

2. Description of the Related Art As a conventional double-sided document reading apparatus, Japanese Patent Laid-Open
The ones described in JP-A-11-122489 and JP-A-2000-209400 are known.

In the double-sided document reading apparatus disclosed in Japanese Patent Application Laid-Open No. 11-122489, after a reference white plate is read by a front side image reading means to obtain a reading reference level, the front side image reading means is positioned at a stop reading position and the document is conveyed. A double-sided white reference document is transported on the road, and the reference document is read by the front-side image reading unit and the back-side image reading unit, and the white level of the reference document is adjusted by the adjustment unit according to the reading level with respect to the reading reference level. Thus, the white level of both sides is adjusted only by passing the reference document once.

A two-sided document reading apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-209400 is composed of a conveyance roller and a conveyance path for reversing the document once, a position before the document is reversed once, and a position after the document is reversed once. And an image pickup unit that receives reflected light from the document and performs photoelectric conversion, and an illumination lamp that illuminates the back surface of the document at a position before the document is inverted once. When reading the front side of the document, the image pickup unit is set at the standard position, the illumination lamp for reading the front surface of the document is turned on, and the illumination lamp for the back surface of the document is turned off. When reading the back side of the original, the image pickup unit is moved in the optical axis direction by a linear distance between the position before the original is inverted once and the position after the original is inverted once, and the illumination lamp for reading the original surface is turned on. The light is turned off and the illumination lamp for reading the back side of the document is turned on.

[0005]

However, the above-mentioned prior art has the following problems. JP 11-122
In the double-sided document reading apparatus disclosed in Japanese Patent No. 489, stray light is generated between the front-side document reading unit and the back-side document reading unit because there is nothing to prevent optical interference between them. Further, when a jam occurs between the front-side original reading means and the back-side original reading means, the jamming is difficult because the reading means faces the occurrence position. Further, since the correction of the white reference is performed by reading the reference white plate and passing the double-sided white reference original, it takes time to adjust the white level.

In the double-sided document reading apparatus disclosed in Japanese Patent Laid-Open No. 2000-209400, the reading process speed is slow because both sides of the document cannot be read simultaneously due to its structure. Further, since the focal length from the document to the lens needs to be adjusted, and since the lens unit driving means is provided, the cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can prevent optical interference between a plurality of document reading units without complicating the structure of a document conveying path. It is another object of the present invention to provide a two-sided document reading apparatus that can be easily downsized.

[0008]

The present invention has the following configuration to achieve the above object. According to a first aspect of the present invention, there is provided a document set unit for setting a document, a discharge unit for discharging a document, a curved conveyance path for guiding a document conveyed from the document set unit to the discharge unit, A first reading unit having a reading area on a side of the curved conveyance path on which one surface of the document faces, and a first reading unit on a side of the curved conveyance path on which the other surface of the document faces; And a second reading unit having a reading area downstream of the reading area in the document conveying direction.
A reversing transport path for reversing the transport direction of the document by about 90 degrees or more; an upstream transport path extending substantially planarly upstream from the reverse transport path in the document transport direction; and a document transport direction extending from the reverse transport path. A downstream transport path extending substantially planarly on the downstream side, wherein the first reading unit is provided in the upstream transport path, and the second reading unit is provided in the downstream transport path. The first reading unit has a first light source that irradiates light to the document and a first light receiving unit that receives light reflected from the document,
The second reading unit includes a second light source that irradiates light to the document and a second light receiving unit that receives light reflected from the document, and the second reading unit includes an equal-magnification optical system. And a double-sided document reading apparatus.

According to a second aspect of the present invention, there is provided a document set portion for setting a document, a discharge portion for discharging the document, and a curved conveyance for guiding the document conveyed from the document set portion to the discharge portion. Path, a first reading unit having a reading area on the side where one surface of the document in the curved conveyance path faces, and the other side of the document in the curved conveyance path facing the other side,
And a second reading section having a reading area downstream of the reading area of the first reading section in the document conveying direction.
A reversing conveyance path for reversing 0 degrees or more, an upstream conveyance path extending substantially upstream from the reversing conveyance path in the document conveyance direction, and a substantially flat shape from the reversing conveyance path to the document conveyance downstream. And a downstream transport path extending to the reverse transport path, wherein a first reading section or a second reading section is provided in the reverse transport path.

According to a third aspect of the present invention, the first reading section has a first light source for irradiating a document with light and a first light receiving section for receiving light reflected from the document. 2 reading unit,
A second feature comprising a second light source for irradiating the original with light and a second light receiving unit for receiving reflected light from the original.
In the double-sided document reading apparatus described in (1).

According to a fourth aspect of the present invention, the first reading section or the second reading section provided in the reverse transport path section is constituted by an equal-magnification optical system. It is in a double-sided document reading device.

According to a fifth aspect of the present invention, there is provided a double-sided document reading apparatus according to the first or fourth aspect, characterized in that a reading section comprising an equal-magnification optical system is provided inside a curved conveying path.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing a configuration example of a double-sided document reading apparatus according to the present invention. The double-sided document reading apparatus includes a lower casing 1, an upper casing 2, and a document discharge tray 3.

The double-sided document reading apparatus can read an image of a document in a stationary reading mode in which the document is stopped and the image is read, or in a traveling reading mode in which the image is read while the document is being conveyed. The traveling reading mode includes a single-sided mode for reading a single-sided image of a document while conveying the document, and a double-sided mode for reading a double-sided image of the document.

In the one-side mode of the stationary reading mode and the traveling reading mode, an image is read by the first reading section 10 in the lower housing 1. In the duplex mode of the traveling reading mode, the first reading unit 10 and the second reading unit 32
Are used at the same time to read images on both sides of the document.

The lower housing 1 is provided with a first reading section 10, a first contact glass 11, and a second contact glass 16. The first reading unit 10 is a reduction optical system (movable optical system), and includes a first scanning unit 12, a second scanning unit 13, an imaging lens 14, and a CCD 15. The first contact glass 11 is a table on which a document to be read in the static reading mode is placed.

The configuration of the first reading unit 10 will be described in more detail. The first scanning unit 12 exposes the document while moving at a constant speed V in the sub-scanning direction (from left to right in the figure) along the first contact glass 11. A first exposure lamp, such as a xenon lamp, for exposing a document is used.
A light source 50, a first reflecting mirror 51, a reflector R, and a slit S for guiding reflected light of the document to the second scanning unit 13;
(Described later).

The second scanning unit 13 follows the first scanning unit 12 and moves at a speed of V / 2. The second scanning unit 13 transmits the light from the first reflecting mirror 51 to the imaging lens 14,
Second and third reflection mirrors 52 and 53 for leading to the CCD 15 are provided.

The image forming lens 14 forms an image of the light reflected from the third reflecting mirror 53 on the CCD 15.
The CCD 15 converts light from the imaging lens 14 into an analog electric signal. This electric signal is
The image data is converted into digital image data by an image processing unit described later and stored in an image memory described later.

A wire (not shown) is wound around the first scanning unit 12 and the second scanning unit 13 so that they can be moved in the same direction in synchronization with each other. Then, it is moved in the left-right direction (sub-scanning direction) of FIG. 1 by a stepping motor (not shown) via this wire.

The first reading section 10 not only reads a document placed on the first contact glass 11 in the stationary reading mode, but also moves the inside of the upper housing 2 in the traveling reading mode as described later. It also has a function of reading an image of a conveyed document.

When reading a document on the first contact glass 11, the first scanning unit 12 moves the document detected by the document size detecting means from the position pos1 to the position pos2 in FIG. It moves by a predetermined distance according to the size. On the other hand, when reading the conveyed document, it stops at the position pos3 in FIG. In addition, during standby when not in use, it is stopped at the position of pos0 (home position) between the positions of pos1 and pos3 in FIG. In addition, pos
The position of 3 indicates that the conveyed document is almost flat (including flat)
Are located on the transport path that forms

As shown in FIG. 2, an original reference plate 41 is provided on the left end side of the first contact glass 11 in the drawing.

On the reference plate 41, an index indicating the size and mounting direction of the original placed on the first contact glass 11 is shown. According to this indicator, the user
An original can be easily placed on the contact glass 11.

Further, on the side of the first contact glass 11 opposite to the side on which the document reference plate 41 is provided, and at a position facing the document reference plate 41, shading of the CCD 15 (determination of white level) is performed. A first reference white plate 42 is provided for use in the operation.

The upper casing 2 is pivoted upward about a hinge (not shown) provided between the lower casing 1 and the lower casing 1 (on the back side of the apparatus). Thus, in this double-sided document reading apparatus, the upper surface of the first contact glass 11 and the upper surface of the second contact glass 16 can be opened from the near side. And the upper housing 2
As shown in FIG. 1, the OC mat 21 and the document tray 2
2, a second reading unit 32, an open door 24, and a document conveying unit 31 are arranged.

The OC mat 21 is a white sheet provided at a position where the upper mat 2 is pressed against the first contact glass 11 when the upper casing 2 is closed, and has an elastic foam such as a sponge on its back side. It has.

The document tray 22 is a table on which documents to be read in the traveling reading mode are placed.

The open door 24 is used to adjust the mounting state of the second reading section 32 and the mounting state of the second reading section 32.
It is an openable and closable door provided on the upper surface of the upper housing 2.

The second reading section 32 is for reading an image of a document placed on the document tray 22, and includes an image sensor section 71 and a holding section. The second reading section 32 reads an image of a conveyed document. The details of the second reading unit 32 will be described later.

The document transport section 31 is a transport section for guiding a document placed on the document tray 22 to a U-shaped transport path 33.

The U-shaped transport path 33 is a transport path that transports the original sent from the original transport section 31 to the reading areas of the first and second reading sections 10 and 32 and guides the original to the original discharge section 34. A curved conveyance path (U-turn paper guide) that curves in a bowl shape or a substantially U shape (including a U shape) in the conveyance direction
A U-shaped conveyance path 33 having a second path 102. Curved transport path 1
02 indicates that the transport direction of the document is substantially reversed before and after that (approximately 180
(Including inversion, 180 degrees)), and it is desirable that the transport path before and after inversion is formed in a laminated shape in which the conveyance paths are substantially parallel (including parallel) in the left-right direction and the depth direction as viewed in the drawing. However, in consideration of the arrangement of components and the like, the transport path before and after the reversal may not be parallel in the left-right direction and / or the depth direction in the drawing. Therefore, the original placed on the original tray 22 is not
The paper 1 is taken into the U-shaped transport path 33 and is substantially inverted by the curved transport path (U-turn paper guide) 102 to be discharged onto the discharge tray 3.

The document discharge section 34 discharges the document whose image has been read by the second reading section 32 to the discharge tray 3.

FIG. 2 shows the document transport unit 31 and the second reading unit 3
FIG. 2 is a partial cross-sectional view showing a configuration near a document discharge unit 34 in detail.

The document conveying section 31 includes a feeding auxiliary roller 61,
Document set detection sensor 62, document holding plate 63, friction pad 64, feed timing sensor 65, feed roller 66,
And an alignment roller pair 67.

Feeding assist roller 61 and document holding plate 63
Is for drawing a document detected by the document set detection sensor 62 into the document transport unit.

The friction pad 64, the feed roller 66, and the alignment roller pair 67 are adapted to read the pulled-in document one sheet at a time based on the detection result of the feed timing sensor 65. Lead to.

The matching roller pair 67 is provided with an electromagnetic clutch (not shown) on its drive shaft, so that transmission of a driving force from a drive motor (not shown) can be controlled. It is stopped in the state. After the leading edge of the document comes into contact with the feed timing sensor 65 and a predetermined signal is transmitted from the timing sensor 65, a predetermined time for forming the deflection of the document upstream of the nip portion of the pair of alignment rollers 67 after the predetermined signal is transmitted. When the time elapses, the document is set to rotate in the direction of transporting the document to the downstream side. After the alignment roller pair 67 is stopped, the leading end of the document conveyed from the upstream side by the friction pad 64 and the feed roller 66 abuts on the nip portion of the alignment roller pair 67, and after a predetermined bending is formed on the document. , So that the document is conveyed downstream. At this time, the document is aligned by the nip portion of the pair of alignment rollers 67 such that the leading end of the document is perpendicular to the transport direction.

The U-shaped conveyance path 33 includes a gap between the conveyance guide 58 and the feeding roller 66, a gap between the alignment roller pair 67 and the second contact glass 16, a curved conveyance path 102, and the document guide 70 and the reference white plate 68. This is a document conveying path having a gap with the original.

The document guide 70 is placed after the U-first rear roller pair 101 with the third contact glass 17 provided at the central opening OP. In addition,
The positions of the document guide 70 and the reference white plate 68 of the second reading section 32 are set by positioning projections 70 a provided with the third contact glass 17 interposed in the conveyance direction of the document guide 70. This will be described later. The third contact glass 17 is provided with a concave opening OP on the conveyance path side of the document guide 70.
Are bonded with an adhesive.

The document discharge section 34 includes a discharge roller pair 69 and a document discharge sensor 59. The upper roller of the discharge roller 69 is a roller on the driving side, is provided integrally on the upper housing 2, and is driven by a driving mechanism in the upper housing 2. The upper roller of the discharge roller 69 has a function of pinching and conveying the document that has passed through the U-shaped conveyance path 33 with the lower roller (driven roller) of the discharge roller 69 and discharging the document onto the discharge tray 3. are doing.

A document discharge sensor 59 is disposed downstream of the discharge roller 69, and detects completion of document discharge.
This is transmitted to a reading control unit described later.

The second reading section 32 is provided in the upper housing 2 and is an image on the back side of the document surface read in the reading area P1 of the first reading section 10 for the document traveling on the U-shaped conveyance path 33. In the reading area P2. Further, the second reference white plate 68 provided opposite to the second reading unit 32 determines the white level when shading the electric signal output from the image sensor unit 71 (determining the white level). And a paper guide for document transport. Further, the second reading unit 32 moves the position of pos3 of the first scanning unit 12 with respect to the position of pos3.
Because of the structure in which the back is turned, the two reading units prevent the images from being unable to be read at an appropriate density.

FIGS. 3 and 4 are explanatory diagrams showing the configuration near the second reading unit 32. FIG. FIG. 3 illustrates an example in which the second reading unit 32 is provided in a downstream linear transport path 33c that extends on a plane on the downstream side in the transport direction of the curved transport path 102 of the U-shaped transport path 33, and FIG. An example is shown in which the reading unit 32 is provided on a flat conveyance path 102a that is substantially straight (including a straight line) and substantially flat (including a plane) provided in a curved conveyance path 102 of a U-shaped conveyance path 33.

That is, the first reading unit 10 and the second reading unit 3
The mounting position of the second reading unit 3 and the second reading unit 3 may be set so that the irradiation lights do not interfere with each other.
It is sufficient if the transport direction in Step 2 is approximately 90 degrees or more (including 90 degrees).

In the case of FIG. 3, the transport direction in the first reading unit 10 and the second reading unit 32 is approximately 180 degrees (including 180 degrees).
In the case of FIG. 4, the document transport direction and the irradiation light direction of the first reading unit 10 and the second reading unit 32 are approximately 90
It has a degree.

Further, in FIG. 4, the curved transport path 102 for substantially reversing the transport direction is used, but a curved transport path for changing the transport direction by approximately 90 degrees may be used due to other members, arrangement space, and the like. it can.

The second reading section 32 includes an image sensor unit 71, a unit fixing plate 73, a unit holding plate 74, and the like.

The image sensor unit 71 is arranged facing the third contact glass 17 provided at the center of the document guide 70. This third contact glass 17
Has a function of realizing light transmission between the image sensor unit 71 and the document and a function of preventing the document from being jammed.

The image sensor unit 71
Is mounted via a unit fixing plate 73 and a unit holding plate 74 with respect to a reference plate 72 fixed between the front and rear frames of the upper housing 2 of the apparatus.

As shown in FIGS. 3 and 4, the image sensor unit 71 has a light source 81 (such as an LED array) for irradiating the original surface, and a selfoc lens for condensing light reflected from the original. The array 82 includes an image sensor (second photoelectric conversion element) 83 that generates an electric signal (electric image signal) according to the intensity of the received light.

The light source 81 is set to have a length capable of irradiating the entire width of the document to be conveyed. In the present embodiment, the light source 81 has substantially the same length as the width of the U-shaped conveyance path 33 perpendicular to the conveyance direction. . Further, two light sources 81 are provided in parallel with respect to the document transport direction with an image sensor (second photoelectric conversion element) 83 interposed therebetween.

When shading the output signal of the image sensor 83, the image sensor unit 71
The second reference white plate 68 is read via the contact glass 17. The shading value is determined based on the read value, and the electric signal output from the second reading unit 32 when the document image is read is shaded (white part level is determined).

The focal point of the selfoc lens array 82 is
The height of the U-shaped conveyance path 33 (the gap between the document guide 70 and the reference white plate 68 of the second reading unit) is slightly higher than the center of the U-shaped conveyance path 33.
The reading unit is set so as to match the reference white plate 68. As a result, the depth of field of the selfoc lens array 82 occupies most of the height of the U-shaped conveyance path 33 from the surface of the reference white plate 68 of the second reading unit. Therefore, the reflected light from the second reference white plate 68 received by the image sensor (second photoelectric conversion element) 83 is at the same level as the reflected light from the white portion of the document passing through the U-shaped conveyance path 33.

Next, the installation configuration of the image sensor unit 71 will be described. FIG. 5 is a partial perspective view showing the configuration of the installation portion of the image sensor unit 71. As shown in the figure, the reference plate 72 has a large opening 72 at the center.
a is formed, and both ends of the opening 72a in the transport direction are bent and raised. A unit fixing plate 73 is hung over the two bent and raised portions 72b, and is fixed by a plurality of fixing screws 76.

The unit holding plate 74 has a hollow quadrangular prism shape. With the unit fixing plate 73 penetrating inside, the unit holding plate 7 is
4 from above.

The image sensor unit 71 is firmly fixed to the unit holding plate 74. In addition, the height position and posture (degree of inclination) of the unit holding plate 74 with respect to the reference plate 72 and the height position and posture of the unit fixing plate 73 with respect to the unit holding plate 74 are adjusted by the fixing screw 76 and the adjusting screw 77. By doing so, it is possible to shift within a predetermined range.

That is, in this double-sided document reading apparatus, the attitude and the height position (the third
The relative position with respect to the contact glass) can be controlled in minute units by adjusting the screws 76 and 77 described above. Accordingly, it is easy to dispose the image sensor unit 71 strictly at an optimum posture and position.

Also, as shown in FIG.
Is fixed to an end of the reference plate 72 by a stepped screw 78 and a guide urging spring 79. This allows U
The height of the character-shaped conveyance path 33 (the distance between the document guide 70 and the second contact glass 16) can be kept constant even if there is a variation in the accuracy of each component.

The adjustment of each screw can be performed from above the upper housing 2 by opening the opening door 24 shown in FIG. Further, as shown in FIG. 6, the opening of the opening door 24 allows the entire second reading unit 32 to be attached and detached.

Next, the reading process in the double-sided document reading apparatus will be described with reference to FIG. In the stationary reading mode, only the first reading unit 10 is used for reading a document. At this time, the first scanning unit 1 of the first reading unit 10
2 is first placed in pos0. Then, in accordance with an instruction from the reading control unit, the scanner moves to the pos2 side together with the second scanning unit 13 while scanning the original placed on the first contact glass 11 from the position of the pos1. This allows the CCD 15 to receive reflected light according to the document image. Thus, the first reading unit 1
0 means that an image formed on the lower surface (front surface) of a stationary document is read.

In the traveling reading mode, both the single-sided mode and the double-sided mode can be selected. In the one-side mode of the traveling reading mode, only the first reading unit 10 is used for reading a document. When there is an instruction in this mode, the first reading unit 10
The first scanning unit 12 moves from the position of pos0 to the position of pos3 in FIG. 1 and stops, and keeps the stopped state to read the traveling document. Then, in response to an instruction from the reading control unit, the CCD 15 reads the image of the document conveyed through the U-shaped conveyance path 33 via the second contact glass 16 from below in FIG. That is, the first reading unit 10 reads an image formed on the lower surface (front surface) of the document.

In the duplex mode of the traveling reading mode, both the first reading section 10 and the second reading section 32 are used for reading a document. At this time, the first scanning unit 12 of the first reading unit 10 is stopped at the position of pos3 in FIG. 1 as in the one-side mode in the traveling reading mode.

Then, according to the instruction of the reading control unit,
The first reading unit 10 reads an image of a document conveyed through the U-shaped conveyance path 33 from below (front side) via the second contact glass 16. Similarly, the second reading unit 32
Reads an image formed on the upper surface (back surface) of FIG. 1 of the document conveyed via the third contact glass 17 from above.

The first reading unit 10 and the second reading unit 32 each include an original sensor (50, 81) and an image sensor (electric image signal) for generating an electric signal (electric image signal) corresponding to the intensity of the received light. 15, 83) and do not share a light source and an image sensor, so in the duplex mode, the first reading unit 10 and the second reading unit 32
The original can be read at any timing, such as simultaneously or consecutively, independently from the vertical and orthogonal directions.
Accordingly, the reading of the document can be completed earlier than in the conventional image reading apparatus in which one reading unit reads one side and then reverses the document to read the other side.

Further, since both sides of the original can be read only by transporting the original using the original transport section 31 and the original discharge section 34 formed in the upper housing 2, the structure can be simplified.

The first reading section 10 is a reduction optical system (movable reading optical system), and the second reading section 32 is a 1: 1 optical system (fixed 1: 1 reading optical system (CIS)). Since the document alignment means needs to be provided only at one location of the first reading unit 10, the conveyance control becomes easy. Therefore, for a user who mostly reads one-sided originals and hardly needs to read two-sided originals, the problem that the apparatus becomes large due to the double-sided original reading function, the configuration becomes complicated, and the cost becomes high is solved. it can.

Further, the second reading section 32 can be arranged inside the U-shaped transport path 33 by using a 1 × optical system (fixed 1 × reading optical system (CIS)). The positions can be diversified, and the size of the device can be reduced, and the degree of freedom in design can be increased.

The positional relationship between the first reading unit 10 and the second reading unit is such that the document is conveyed in a direction substantially 90 degrees or more, for example, approximately 180 degrees in the case of FIG. 3 and 180 degrees in the case of FIG. Is set to approximately 90 degrees, it is possible to prevent the irradiation lights of the reading units from interfering with each other.

In this double-sided document reading apparatus, the second reading section 32 can be attached and detached by opening the opening door 24. That is, the second reading unit 32 can be mounted from above the transporting unit with few other members. This allows
The attachment / detachment of the second reading unit 32 can be facilitated. Further, the degree of freedom in designing other members can be increased.

Further, in this double-sided document reading apparatus, the height position and posture of the image sensor unit 71 in the second reading section 32 can be easily adjusted with respect to the U-shaped conveyance path 33. Thereby, it is possible to easily eliminate the displacement of the second reading unit 32 which causes the deterioration of the image quality.

Further, in this double-sided document reading apparatus, the height position and posture of the document guide 70 can be adjusted. Accordingly, the height of the U-shaped conveyance path 33 (the height of the third contact glass 17) can be set to an optimum value, and thus a sheet jam can be prevented.

Next, a control system in the double-sided document reading apparatus will be described with reference to FIG. In FIG. 7, the system controller 84 transmits
It controls the reading control unit 86, and further controls the image processing relay unit 88 and the image memory 89 via the system bus 87. Thus, the system controller 84 controls the entire double-sided document reading device so that the document reading operation is properly performed.

The first light source substrate 90 turns on and off the light source 50 of the first reading unit 10 based on the signal of the reading control unit 86. The second light source substrate 91 turns on / off the light source 81 of the second reading unit 32 based on a signal from the reading control unit 86.

First reading scanning system drive motor control board 92
Controls the first reading / scanning system driving motor 93 based on the signal of the reading control unit 86 to move the first scanning unit 12 and the second scanning unit 13 in both the left and right directions in FIG.

The first reading scanning system position sensor group 94 includes a first scanning unit 12 for pos0, pos1, pos2,
When it is located at pos3, it sends a reference position signal to the reading control unit 86.

The reading control unit 86 determines the first scanning unit 12 based on the reference position signal of the first reading scanning system position sensor group 94 and the number of steps of the first reading scanning system driving motor 93.
Is calculated, and the first reading / scanning system drive motor 93 is controlled to rotate forward / reverse to reciprocate the scanning units 12 and 13.

The drive motor control board 95 of the automatic document feeder (document transport section 31, document discharge section 34) controls the drive motor 96, which is a stepping motor, on and off in response to a signal from the read control section 86, thereby automatically feeding the original. Devices 31, 3
The drive system of No. 4 is driven to transmit the driving force to the above-described paper feed rollers 61 and 66, the separation / feed unit, the pair of alignment rollers 67, the discharge roller 69, and other transport rollers. The drive motor 9
6 can change the rotation speed by the pulse rate from the drive motor control board 95.

The document discharge sensor 59, document set detection sensor 62, and feed timing sensor 65 (document detection sensor group) transmit a document presence / absence signal to the reading control unit 86 when the document reaches the position of each sensor. .

On the other hand, the reading control unit 86 calculates whether or not the original is being conveyed at an appropriate timing based on the presence / absence signal of the original from the sensor groups 59, 62 and 65 and the timer. In the case of a failure, a signal of occurrence of a jam or the like is transmitted to the system controller 84 via the system bus 87.

The document conveying roller clutch group 97 is turned on / off by a signal from the reading control unit 86 to switch connection or non-connection to each drive system of the automatic document feeder, thereby stopping the drive system. Or rotate.

Next, the processing of the electrical image signal obtained by the reading scan in the single-sided reading mode and the double-sided reading mode will be described.

The CCD 15 and the second reading section 32 (CIS
83), the electrical image signal (hereinafter, referred to as an image signal) is sent to an image processing unit IP, and after being subjected to predetermined image processing, sent to an image processing relay unit 88.
After predetermined image processing is performed, the system bus 87
And stored in the image memory 89 while being distinguished for each page.

The image processing unit IP includes an analog signal processing unit I
1, an A / D conversion unit I2, a shading correction unit I3, a filter processing unit I4, and a density conversion unit I5.
Each element of the image processing unit IP operates under the control of the reading control unit 86.

The analog signal processing section I 1
The image signal input from the CD 15 and the second reading unit 32 (CIS 83) is subjected to a level conversion process, a sample hold process, and a signal amplification process, and is output to the A / D conversion unit I2. Since the CCD 15 and the second reading unit 32 have different light source light amounts, photoelectric conversion efficiencies, output signal levels, and the like, dedicated analog signal processing units I1 are provided for the CCD 15 and the second reading unit 32, respectively.

The A / D conversion section I2 converts the analog image signal input from the analog signal processing section I1 into a digital signal, and converts the quantized image signal into a shading correction section I3.
Output to

The shading correction section I3 performs black reproduction and white reproduction on the quantized image signal input from the A / D conversion section I2, and outputs the result to the filter processing section I4.

The black reproduction means that the implicit output of the CCD 15 or the second reading unit 32 is sampled and stored, and the read data is subtracted from the image signal output from the CCD 15 or the second reading unit 32 when reading the original document. By doing
This is to remove the effect of the implied output.

The white reproduction means that an image signal at the time of reading a document is normalized to each pixel based on an image signal of each pixel when a reference white plate having a uniform reflectance is read, and the influence of uneven light amount and optical components. And correcting the variation in pixel sensitivity of the first photoelectric conversion element 15 and the second photoelectric conversion element 83.

Filter processing section (filter processing means) I4
A predetermined filtering process based on a coefficient that determines a filter characteristic set from the reading control unit 86 on the image signal input from the shading correction unit I3, specifically,
By performing a spatial filtering process, high-frequency components of the image are emphasized, and "blur" of the image is restored.

That is, the CCD 15 and the second reading unit 3
The image signal output by the optical disc 2 includes optical components such as a lens and a mirror, the aperture opening of the light receiving surface of the CCD 15 and the second reading unit 32, the transfer efficiency and the afterimage of the CCD 15 and the second reading unit 32, and the physical scanning. The MTF (Modulation Transfer Function) is deteriorated due to the integration effect and scanning unevenness, and the filter processing unit I4 compensates for the MTF deterioration.

As described above, the MTF is connected to the CCD 15 and the second
Since the degree of deterioration greatly differs depending on the reading unit 32, appropriate filtering is performed. Further, since the deterioration of the MTF is more remarkable in the higher frequency range, the filter processing unit I4
In the Japanese Patent Application Laid-Open No. H08-115, an image signal in a high-frequency range is subjected to an emphasis process, thereby correcting "blur" and improving image quality.

The filter processing unit I4 determines that the input image signal is C
Different filter processing is performed depending on whether the signal is an image signal from the CD 15 or an image signal from the second reading unit 32.

Density conversion unit (density conversion means, binarization means)
I5 is for performing density conversion on the image signal filtered by the filter processing unit I4. For example, the image signal is transmitted when facsimile communication of the image signal is performed or when the printing condition is designated to be binarized. Is binarized, and
If the printing condition is multi-valued, such as a photographic image, the image quality is improved by performing density conversion using a predetermined density characteristic.

The density converter I5 includes a RAM, a RAM controller (not shown), and performs data conversion by reading a lookup table for data conversion set in the RAM as an address of an input image signal. hand,
Perform density conversion processing. The image signal for which the density conversion processing has been completed is stored in the image memory 89.

Hereinafter, the features of the present invention will be described in detail with reference to FIGS. In the embodiment shown in FIG. 3, a curved transport path 102 is provided in the U-shaped transport path 33, and the first scanning unit 12 (pos 3 position), which is the first reading unit 10, is located upstream of the curved transport path 102, and downstream. A second reading unit 32 is provided so as to face the first scanning unit 12. That is, the first reading unit 10 that reads the surface of the document is substantially straight (including a straight line) extending upstream of the curved conveyance path 102 of the U-shaped conveyance path 33 in the document conveyance direction, and upstream of a substantially flat surface (including a flat surface). The second reading unit 32 that is disposed in the transport path 33b and reads the back surface of the document is disposed in a substantially straight, substantially planar downstream transport path 33c that extends downstream of the curved transport path 102 in the document transport direction.

In the configuration shown in FIG. 3, when the original sent by the original transport unit 31 passes over the second contact glass 16, the first reading unit 10 reads the front surface of the original in the reading area P1. Further, the original is conveyed by the pair of rollers 100 before the U-turn, reversed by the curved conveying path 102, and the third contact glass 1 by the pair of rollers 101 after the U-turn.
Send out on 7. When the document passes over the third contact glass 17, the reading area P is read by the second reading unit 32.
In step 2, the back side of the document is read.

According to the above configuration, the second reading section 32 is disposed so as to face the first reading section 10, and the U-shaped transport path 33 is provided between the reading sections 10 and 32. The two reading units 1
0 and 32 can be prevented from optically competing with each other.

Further, since the two reading units 10 and 32 can be arranged in a stack, the size of the apparatus can be reduced. Further, since only the U-turn is carried from the entry to the exit of the document, the structure of the document transport path is not complicated, so that a jam is less likely to occur.

The reading units 10 and 3 are provided on the upstream and downstream straight transport paths 33b and 33c of the curved transport path 102, respectively.
Since the gap 2 is provided, even if the gap of the U-shaped conveyance path 33 through which the sheet passes is narrowed, no jam occurs and the reading can be stably performed.

Further, since the second reading section 32 is constituted by an equal-magnification optical system (fixed optical system) which can be formed compactly,
Since the apparatus can be arranged inside the character-shaped transport path 33, the apparatus can be easily reduced in the height direction.

Further, the U-shaped conveyance path 33 is
The upper side can be opened, so that the jam can be easily removed.

In the embodiment shown in FIG. 4, a curved transport path 102 is provided in the U-shaped transport path 33, and the first scanning unit 12 (p
os3 position), the second reading unit 32 is provided in the flat transport path 102a in the middle of the curved transport path 102. That is, the first reading unit 10 for reading the front side of the original is
The second reading unit 32 that reads the back side of the original is disposed on the flat transport path 102a of the curved transport path 102.

In the configuration shown in FIG. 4, when the original sent by the original transport unit 31 passes over the second contact glass 16, the front surface of the original is read in the reading area P2 of the first reading unit 10. The document is further conveyed by the pair of rollers 100 before the U-turn, and when the document located in the middle of the curved conveyance path 102 passes in front of the third contact glass 17, the back side of the document is Is read.

According to the above configuration, the reading direction of the second reading section 32 is substantially orthogonal (approximately 90 ° inclined) to the reading direction of the first reading section 10, and both reading sections 10, 32
Since the light-blocking member constituting the U-shaped transport path 33 is interposed therebetween, it is possible to prevent the two reading units from optically competing with each other.

Further, the second reading section 32 is
a, the reading area P of the second reading unit 32
Since the document does not bend when passing through the document 2, the image of the document is not read while being curved.

Further, the second reading section 32 is in a sideways posture, that is, the direction of the optical axis of the reflected light incident on the image sensor 83 from the original is the upper and lower linear portions 33b,
By being provided so as to be substantially parallel to (including parallel to) 33c, the device can be further reduced in the height direction as compared with the case of FIG.

In the above-described embodiment, the image is read using the first reading unit 10 in the one-sided mode of the traveling reading mode. However, the present invention is not limited to this. The image reading may be performed using only 32.

[0109]

As described above, according to the first aspect of the present invention, there is provided an upstream conveyance path extending from the reverse conveyance path to the upstream side in the document conveyance direction in a substantially planar shape; The first reading section and the second reading section provided on the downstream side transport path section extending in a substantially planar shape on the downstream side in the document transport direction are provided with a light source and a light receiving section, respectively, so that the first reading section and the second reading section are provided. It is possible to read the front and back sides of the same original independently of each other while preventing optical mutual interference of the copies, thereby shortening the duplex copying time. By configuring the second reading unit with the same-magnification optical system, the distance (optical rejection) between the reading area and the light receiving element of the reading unit is longer than that of the equal-magnification optical system. As compared with a case where a reading unit is arranged, a compact configuration can be achieved, so that the degree of freedom in design can be increased.

According to the second aspect of the present invention, one of the reading sections is provided in the reversing conveyance path section for reversing the conveyance direction of the original by about 90 degrees or more, so that the first reading section and the second reading section can be mutually connected. The duplex document reading apparatus can be configured with a compact configuration while preventing optical mutual interference.

According to the third aspect of the present invention, the first reading unit and the second reading unit are individually provided with the light source and the light receiving unit, respectively, so that the first reading unit and the second reading unit are optically connected to each other. The front and back sides of the same original can be read independently of each other while preventing mutual interference, and the duplex copying time can be reduced.

According to a fourth aspect of the present invention, the first reading section or the second reading section provided in the reverse transport path section is constituted by an equal-magnification optical system. Since the distance (optical rejection) between the reading area and the light receiving element of the reading unit is long and a reading unit composed of a reduced optical system having a large size is arranged, the configuration can be made more compact because of a compact configuration. Can be increased.

According to the fifth aspect of the present invention, by providing the reading section composed of the equal-magnification optical system on the inside of the curved path of the curved conveyance path, the inside of the curved conveyance path can be effectively utilized, and the compact size can be achieved. With this configuration, a double-sided document reading device can be configured.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of an embodiment of a duplex document reading apparatus according to the present invention.

FIG. 2 is a partial cross-sectional view showing a more detailed configuration of a part of the duplex document reading apparatus of FIG. 1;

FIG. 3 is an enlarged view showing a configuration example of a portion of a U-shaped conveyance path.

FIG. 4 is an enlarged view showing another example of the configuration of the portion of the U-shaped conveyance path.

FIG. 5 is a partial perspective view illustrating a configuration of an installation unit of a second reading unit.

FIG. 6 is an operational explanatory diagram of an attaching / detaching operation of a second reading unit.

FIG. 7 is a block diagram illustrating a configuration of a control system of the duplex document reading apparatus.

[Explanation of symbols]

 3 Document discharge tray 10 First reading unit 15 CCD 22 Document tray 32 Second reading unit 33 U-shaped conveyance path 33b Upstream conveyance path 33c Downstream conveyance path 50 First light source 81 Light source 83 Image sensor 102 Curved conveyance path 102a Flat transport path P1, P2 Reading area

Continued on the front page (72) Inventor Masayuki Ida 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Hidenori Onishi 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Masami Tsuchida 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka, Japan (72) Inventor Eiji Sato 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 2H076 BA17 BA24 BA35 BA36 BA47 BA49 BA58 BA63 3F102 AA14 AB01 BA11 BB17 CA01 CB01 DA08 EA03 EC01 5B047 AA01 BA01 BB02 BC05 BC09 BC11 BC14 BC18 5C072 AA01 BA01 BA02 CA02 DA02 DA04 DA21 DA25 EA05 EA07 NA01

Claims (6)

[Claims] 1. A document setting section for setting a document, a discharge section for discharging a document, a curved conveyance path for guiding a document conveyed from the document setting section to the discharge section, and a curved conveyance path. A first reading unit having a reading area on one side of one side of a document in the middle, and a reading area of the first reading unit on the side of the curved conveyance path on the side opposite to the other side of the document; And a second reading unit having a reading area on the downstream side in the document transport direction. The curved transport path includes a reverse transport path unit that reverses the transport direction of the document by about 90 degrees or more. An upstream transport path portion extending in a substantially planar shape from the reverse transport path portion to the document transport direction upstream side, and a downstream transport path portion extending in a substantially planar shape from the reverse transport path portion to the document transport direction downstream side, The first reading unit is provided in the upstream transport path unit, The second reading unit is provided in the downstream transport path unit, and the first reading unit includes a first light source that irradiates light to the document and a first light receiving unit that receives reflected light from the document. Wherein the second reading unit has a second light source for irradiating the original with light and a second light receiving unit for receiving reflected light from the original; A double-sided document reading device comprising: 2. The double-sided document reading apparatus according to claim 1, wherein the second reading unit is provided inside a curved conveyance path. 3. A document setting section for setting a document, a discharge section for discharging the document, a curved conveyance path for guiding the document conveyed from the document setting section to the discharge section, and the curved conveyance path. A first reading unit having a reading area on one side of one side of a document in the middle, and a reading area of the first reading unit on the side of the curved conveyance path on the side opposite to the other side of the document; The double-sided document reading apparatus further includes a second reading unit having a reading area on the downstream side in the document conveyance direction. The curved conveyance path includes a reversal conveyance path that reverses the conveyance direction of the document by about 90 degrees or more; An upstream transport path extending substantially planarly upstream from the transport path in the document transport direction, and a downstream transport path extending substantially planar downstream from the reverse transport path in the document transport direction; The first reading unit or the second reading unit is the reverse conveyance path unit A double-sided document reading device is provided in the document. 4. The first reading section has a first light source for irradiating light to the document and a first light receiving section for receiving reflected light from the document, and the second reading section includes: 4. The double-sided document reading apparatus according to claim 3, further comprising a second light source that irradiates light and a second light receiving unit that receives reflected light from the document. 5. The double-sided document reading device according to claim 3, wherein the first reading unit or the second reading unit provided in the reverse conveyance path unit includes an equal-magnification optical system. 6. The double-sided document reading apparatus according to claim 5, wherein the first reading section or the second reading section provided in the reverse conveyance path section is provided inside a curved conveyance path.