JP2004336275A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image scanner for obtaining an excellent image without causing inclination or the like that warrants the perpendicularity of the image by a rear side read unit in the both side simultaneous reading. <P>SOLUTION: The rear side read unit is supported by a support means provided with an adjustment mechanism whose angle is changed with respect to carrying rollers. A second read unit 60 is configured as a unit by integrating read means 62, 63, 64, a positioning means 83, a fixing means 84, and paper guide means 82, 61 so as to be easily replaceable. Since the second read unit 60 is adjusted on the basis of a resist roller 12, that is, relative to an original carrying direction and thereafter positioned, the original carrying direction and a read line (main scanning) are kept perpendicular to each other so as to avoid the original from being obliquely read. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a document feeder provided with image reading means for reading an image of a sheet material (document) on which an image is placed, such as a scanner, a copier, a printer, or a facsimile machine.
[0002]
[Prior art]
Conventionally, for example, a document feeder is disposed above an image reading unit of an image forming apparatus such as a copying machine, and automatically separates a plurality of documents (sheet materials) stacked on a document tray one by one by a separating unit. Various types of document feeders have been proposed which feed the document to a predetermined section such as an image reading section, and convey the document to the predetermined section such as an image reading section.
[0003]
In JP-A-9-46472, a front image of a document to be conveyed is read by a first image reading unit, and a back image is read by a second image reading unit. That is, reading is performed by another reading means. The second reading means inside the document feeder is removable (removable).
[0004]
[Problems to be solved by the invention]
However, in the above-mentioned conventional example, the position of the second reading unit that reads the image on the back surface (the second surface) disposed inside the document feeder is made removable (removable), so that the positional accuracy deteriorates, and There is a problem that the image is not perpendicular to the transport direction and the image is read obliquely. Further, there is a problem that the position is not accurately fixed in the document conveyance direction as described above due to the variation of components. Further, since the distance between the reading surface and the document surface cannot be kept constant, the document surface is separated from the reading surface. There are issues such as image distortion, out of focus, and fog.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to the present application provides a sheet conveying unit that conveys a sheet on which an image is formed, and a first image reading unit that reads an image of a first surface of the sheet conveyed by the sheet conveying unit. A first image reading unit, comprising: a sheet receiving member; and a first image reading unit configured to read an image of a first surface of the sheet passing through a surface of the sheet receiving member. The sheet conveying unit has a sheet conveying unit and a second image reading unit that reads an image of a second surface of the sheet conveyed by the sheet conveying unit, and holds the second image reading unit and holds the second image reading unit. With the holding means for adjusting and fixing the position by changing the position, there is an effect that the positioning can be accurately performed in the sheet material conveying direction.
[0006]
The second reading means has a function of maintaining a stable distance of the sheet material to be conveyed with respect to the reading surface of the reading means by integrally forming a sheet conveying guide near the reading unit.
[0007]
Since the second reading unit is detachable and replaceable, it is possible to easily provide a single-sided reading sheet material conveying device or a double-sided reading sheet material conveying device.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An image reading apparatus according to an embodiment of the present invention and a copying machine which is an image forming apparatus provided with the image reading apparatus in an apparatus main body will be described with reference to the drawings.
[0009]
(Example)
[Explanation of device]
In FIG. 1, a document processing device (automatic document feeder of the present invention) 2 which is a sheet material transfer device of the present invention has a document tray 4 above, and a discharge tray 10 below it. . The originals P on the original tray are sequentially separated and fed one by one from the uppermost sheet, and the images of the originals are read while being transported. When the reading of the image is completed, the sheets are discharged and stacked on the discharge tray 10.
[0010]
The copying machine main body 1 includes an image input unit 150 (hereinafter referred to as a reader unit) and an image output unit 300 (hereinafter referred to as a printer unit).
[0011]
The reader unit 150 is a well-known image reading unit that optically reads the image information recorded on the document P, photoelectrically converts the image information, and inputs the image data as a reading platen 161, a book platen 3, and a lamp 152. , A scanner unit 154 having a mirror 153, mirrors 155 and 156, a lens 157, an image sensor 158, and the like. When reading the document of the document processing apparatus 2, the scanner unit is stopped at the position 160 to read the image of the moving document, and when the document processing apparatus 2 is not used, the document placed on the platen 3 is scanned. The original image is read by moving the unit. The document processing device 2 is opened and closed with respect to the book platen 3 by a hinge (not shown), and the document processing device 2 is opened and closed to place a document on the book platen 3.
[0012]
The printer unit 300 is an image forming unit using well-known electrostatic latent image formation.
[0013]
A description will be given of the printer unit 300 as an image output unit from FIG.
[0014]
Reference numeral 100 denotes an upper cassette. Sheets in the cassette are separated and fed one by one by the action of a separation claw and a feeding roller 101, and are guided to a registration roller 106. Reference numeral 102 denotes a lower cassette. Sheets in the cassette are separated and fed one by one by the action of a separation claw and a feeding roller 103, and are guided to a registration roller 106. A manual guide 104 guides sheet materials one by one to a registration roller 106 via a roller 105. Reference numeral 108 denotes a sheet stacking device (deck type) having an intermediate plate 108a which is moved up and down by a motor or the like. The sheets on the intermediate plate are separated and fed one by one by the action of a feeding roller 109 and a separating claw, and are conveyed by a conveying roller 110. Is led to.
[0015]
Reference numeral 112 denotes a photosensitive drum, 114 denotes a developing device, 115 denotes a transfer charger, and 116 denotes a separation charger, and constitutes an image forming unit.
[0016]
Reference numeral 117 denotes a conveying belt for conveying the sheet material on which an image is formed, 118 denotes a fixing device, 119 denotes a conveying roller, and 120 denotes a diverter. The sheet material on which the image is formed is guided to the discharge roller 121 by the diverter 120 and is conveyed into the sorter 122. The sorter 122 includes a non-sort tray 122a, a sort bin tray 122b, a non-sort tray discharge roller 122c, and a sort bin tray discharge roller 122d. Note that a discharge tray may be mounted instead of the sorter.
[0017]
In the case of double-sided copying or multiple copying, the sheet after fixing is branched by a diverter 120 and conveyed by a conveying roller 201. In the case of double-sided copying, the sheet is discharged to an intermediate tray 200 via belts 202 and 204, a path 206, and a discharge roller 205. Is done. In the case of multiple copying, the sheet is discharged to the intermediate tray 200 by the diverter 203. 209 and 210 are half-moon rollers for feeding the sheet, 211 is a separation roller pair, and 213, 214 and 215 are conveyance rollers for conveying the sheet to the registration roller 106.
[0018]
[Description of Document Tray]
In FIG. 1, a document tray 4 is for stacking sheet-shaped documents P. A pair of width direction regulating plates are slidably disposed on the document tray 4 in the width direction of the document. By restricting the width direction of the documents P stacked on the document tray 4 by the width direction regulating plate, it is possible to secure the conveyance stability at the time of feeding.
[0019]
[Explanation of separation unit]
Above the document tray 4, a paper feed roller 5 is provided. The paper feed roller 5 rotates with the rotation of the separation / conveyance roller 8 and feeds a sheet document.
[0020]
The paper feed roller 5 is normally set at a position retracted above the home position (solid line position in the figure) so as not to hinder the original setting operation. When the sheet feeding operation is started, the sheet P moves down to a position indicated by a dotted line in FIG. Since the paper feed roller 5 is supported by an arm (not shown), the arm can be swung to move the paper feed roller 5 up and down.
[0021]
The separation pad 6 is arranged on the side opposite to the separation and conveyance roller 8, and applies pressure to the separation and conveyance roller 8 side.
[0022]
The separation pad 6 is formed of a rubber material or the like having a slightly smaller friction than the separation and conveyance roller 8. The separation pad 6 separates the document P fed by the sheet feeding roller 5 sheet by sheet and feeds the document P by the separation and conveyance roller 8.
[0023]
[Description of transport unit]
The registration roller 12 and the registration driven roller 11 are registration means for aligning the leading edge of the document fed at the separation unit. The registration roller 12 and the registration driven roller 11 abut against the leading edge of the separated document toward the nip portion of the stationary registration roller pair 11, 12. A loop is created and the tips are aligned. Reference numeral 69 denotes a document loop space.
[0024]
Next, the sheet is conveyed toward the platen glass 161 by the lead roller 22 and the lead driven roller 14. The sheet is further conveyed by a lead discharge roller 23 and a lead discharge driven roller 16.
[0025]
The platen roller 24 is rotated at the same peripheral speed as the read roller 22. The platen roller 24 is a roller having a white surface, and is not affected by the roller surface at the time of image reading even for a thin original which is easily transparent.
[0026]
Reference numeral 162 denotes a jump table for scooping up a sheet from the reading platen 161.
[0027]
When the image reading is completed, the document is discharged to the discharge tray 10 by the discharge roller 18.
[0028]
[Description of Second Reading Unit]
The front surface (upper surface in the figure) of the document P stacked on the document tray 4 is the first surface, and the back surface is the lower surface (lower surface in the diagram). The second reading unit 60 disposed inside the automatic document feeder is dedicated to the second surface.
[0029]
When the copy mode is selected, the reading operation is performed only under the input conditions of the duplex mode.
[0030]
The second reading unit 60 is disposed immediately after the registration roller 12. Inside, an LED 64 as a light source for illumination, a lens 63 for imaging, and a contact sensor 62 for reading are arranged. Further, the second reading unit 60 is configured to be easily detachable and replaceable, and to maintain a position based on the registration roller 12. Outside the paper passage area of the second reading unit 60, that is, on both sides, the registration roller 12 is mounted on a bearing 9 provided with a holder portion 83 and rotatably supporting the shaft 21 of the registration roller 12. The second reading unit 60 is fixed by fixing the fixing portion 84 to a frame or the like with a screw 81. Further, a portion 82 between the reading line, which is the main scanning, and the registration roller 12 functions as a paper guide.
[0031]
FIG. 5 is a plan view showing the periphery of the second reading unit 60. Regarding the positioning of the second reading unit 60 in the document conveying direction, that is, the sub-scanning direction, the back side in the figure is fixed with reference to the registration roller 12. On the other hand, a long hole 90 is arranged on the front side, and can be changed and adjusted in the sub-scanning direction as indicated by an arrow in the figure, and can be fixed with a screw 81. Therefore, the second reading unit 60 can be tilted as needed with respect to the document transport direction by the registration roller 12, so that the squareness can be adjusted. Even if there is a variation in parts or the document is slightly obliquely conveyed, the original is not read obliquely by adjusting and fixing the second reading unit 60 vertically.
[0032]
In the adjusting method, the document is stopped when the leading end of the document has reached the leading end of the second reading unit, and adjustment is performed so that the leading end of the document and the second reading unit 60 match.
[0033]
In addition, the second reading unit 60 may be adjusted so that the drawing on which the right-angled image is drawn is used as a document and the image is taken to reproduce the right-angled image.
[0034]
FIG. 4 shows a state in which the cover 70 is opened at the time of jam clearance. In this state, the second reading unit 60 can be easily removed or replaced by shifting the bearing 9 in the thrust direction.
[0035]
A white plate 61 is arranged on the side of the second reading unit 60 facing the reading line, and is urged toward the reading side by a spring 65. Due to the urging force of the white plate 61, the original image surface can always be stably pressed against the second reading unit 60 side even under different conditions such as the thickness and waist of the original, and a stable image can be obtained. The gap between the white plate 61 and the reading surface is ensured by the white plate boss 85 outside the paper passing area abutting on the reading surface. The surface of the white plate is white, and is not affected even by a thin and easily transparent original.
[0036]
The same applies to the case where the white plate is a film-like sheet and is urged against the reading surface by its own elastic force. The same applies to the case where the roller is driven to rotate by a white roller instead of the white plate.
[0037]
The second reading unit 60 is constituted by a unit integrating the reading means 62, 63, 64, the positioning means 83, the fixing means 84, and the paper guide means 82, 61, and adjusts with respect to the registration roller 12, that is, the document conveying direction. Since the document is positioned after the scanning, the document conveying direction and the reading line (main scanning) are kept perpendicular, and the document is not read obliquely.
[0038]
The guide 82 and the white plate 61 are also integrally formed by the reading unit and the unit, and their relative positions are guaranteed, so that the original does not float on the reading surface and distortion of the image can be prevented.
[0039]
In FIG. 7, a dummy guide 80 having no reading function is mounted instead of the second reading means 60. For example, a document feeder that does not require a double-sided reading function is provided by mounting a dummy guide 80. When a double-sided reading function is required, a second reading unit 60 can be provided to easily handle a document that meets the needs. It becomes possible to provide a feeding device. Since the dummy guide 80 and the second reading unit 60 are compatible with each other in terms of the mounting method, they can be coped with at low cost.
[0040]
[Description of First Reading Unit]
The platen roller 24 is disposed on the side opposite to the reading unit 160 shown in FIG. The platen roller 24 is rotated at the same peripheral speed as the read roller 22. The platen roller 24 is a rubber roller having a white surface, and is not affected by the roller surface at the time of image reading even for a thin original which is easily transparent.
[0041]
The reader unit 150 is configured by a known reduction optical system. The image information recorded on the document P is optically read, photoelectrically converted, and input as image data. The scanner unit 154 includes a reading platen 161, a book platen 3, a lamp 152, and a mirror 153, and a mirror 155. , 156, a lens 157, an image sensor 158, and the like. When reading the image on the first side, the first reading unit is stopped at the position of 160, and the image of the original on the first side is read. When the document processing device 2 is not used, a stationary document placed on the platen 3 is read by moving the first reading unit in the left-right direction in FIG.
[0042]
In addition, as shown in FIGS. 6 and 7, the reader unit 170 may use a contact type sensor without any limitation. That is, in the first reading unit 172, an LED 171 as a light source for illumination, a lens 174 for imaging, and a contact sensor 173 for reading are arranged.
[0043]
[Description of drive system]
FIG. 3 is a diagram showing a drive system showing a motor for driving each roller and the like and solenoids.
[0044]
The separation solenoid 57 drives the swing of the sheet feeding roller 5. The separation solenoid 57 is a keep solenoid that lifts and holds the paper feed roller 5 above the home position (solid line position in the drawing) and holds the paper feed roller 5 at a position where it does not hinder the document setting. During the paper feeding operation, the keeping force of the separation solenoid 57 is turned off to descend, and the paper feeding roller 5 is pressed against the uppermost sheet of the sheet document on the document tray 4.
[0045]
The separation motor 51 is a stepping motor, and drives the separation roller 8 and the paper feed roller 5 to rotate in the transport direction.
[0046]
The read motor 53 is a stepping motor that drives the registration roller 12, the read roller 22, the platen roller 24, and the lead discharge roller 23. Each roller is driven at a speed for reading the image of the conveyed document.
[0047]
The paper discharge motor 50 is a stepping motor that drives the paper discharge roller 18.
[0048]
[Description of sensor]
The document tray 4 is provided with a document set detection sensor 40 which is a transmission type optical sensor for detecting that the sheet document P is set.
[0049]
A paper width detection sensor 44 for detecting the length of the document bundle P set on the document tray 4 in the width direction by detecting the position of the side guide is provided at the lower portion of the document tray 4.
[0050]
A registration sensor 7, which is a transmission type optical sensor for detecting a document, is provided between the separation roller 8 and the registration roller 12, detects the leading end of the separated and fed document, and abuts on the registration roller 12 ( Loop amount) is detected.
[0051]
Further, the signal of the registration sensor 7 is used as a reference signal of the second surface image reading start timing. Since the second reading unit is immediately after the registration roller 12 and the registration sensor 7 is close to the second reading unit, there is an effect that the deviation of the reading start is small. Therefore, image reading without image registration deviation is performed.
[0052]
Immediately after the read roller 22, there is provided a read sensor 13 which is a reflection type optical sensor for detecting a document, and serves as a reference signal for image reading start timing in the first surface image reading unit 160.
[0053]
Immediately before the paper discharge roller 18, a paper discharge sensor 17, which is a transmission type optical sensor for detecting a document, is provided, and detects a document discharge timing and the like.
[0054]
[Description of feeding operation]
When a document P on the document tray 4 is detected by the document set sensor 40, the paper feed roller 5 descends and comes into contact with the document bundle.
[0055]
When a copy condition is input on the operation unit of the copying machine and the start key is pressed, the document size is detected by the document width sensor 44 on the document tray 4. Further, the holding of the separation solenoid 57 is released, and the document advances to the downstream portion under the feeding force of the sheet feeding roller 5.
[0056]
Next, the originals P advanced from the original tray 4 are separated one by one and conveyed to a downstream portion.
[0057]
The document P passing through the separation unit is read by the second reading unit 60 on the second surface while the leading edge of the document P is aligned by the registration roller 12 and transported by the registration roller 12.
[0058]
While the image on the second surface is being read, the leading end reaches the lead roller 22 and is conveyed toward the platen glass 161, and while being conveyed by the platen roller 24 and the lead discharge roller 23, the first reading unit 160 Image reading of the surface is performed simultaneously.
[0059]
When the image reading is completed, the sheets are stacked on the discharge tray 10 by the discharge rollers 18.
[0060]
[Description of control circuit block]
FIG. 8 is a block diagram showing a circuit configuration of the control device according to the present embodiment. The control circuit mainly includes a microprocessor (CPU) 54, and input / output ports of the CPU 54 include drive circuits for various loads. And a sensor signal are connected.
[0061]
The control circuit includes a RAM that is backed up by a battery (not shown) and a ROM that stores control sequence software. Reference numeral 55 denotes a communication IC for controlling data communication with the copying machine main body.
[0062]
The separation motor 51, the read motor 53, and the paper discharge motor 50 are driven by respective stepping motor drivers. Each driver receives a phase excitation signal and a motor current control signal from the CPU 254.
[0063]
The separation solenoid 57 is driven by a driver, and its operation is controlled by a signal connected to an input / output port of the CPU 54.
[0064]
Various sensors such as the registration sensor 7, the set sensor 40, the lead sensor 13, the paper ejection sensor 17, and the tray width sensor 44 are connected to the input port of the CPU 54 to monitor the behavior of the original and the behavior of the movable load in the apparatus. Used to monitor.
[0065]
(Other embodiments)
FIG. 6 shows a configuration of another image reading apparatus and a document feeder according to another embodiment. As the first reading unit 172, a contact type sensor in which an LED 171 as a light source for illumination, a lens 174 for imaging, and a contact sensor 173 for reading are arranged is used. Further, since the second reading unit 200 is positioned on the lead discharge roller 23 and can be fixed by adjusting the inclination with respect to the document conveying direction by the discharge roller 23 as in the present embodiment, the document can be read obliquely. Therefore, the same effect as in the present embodiment can be obtained.
[0066]
【The invention's effect】
As described above, the second reading unit 60 is constituted by a unit in which the reading means 62, 63, 64, the positioning means 83, the fixing means 84, and the paper guide means 82, 61 are integrated, and can be easily replaced. 12, that is, the positioning is performed after adjusting the document conveyance direction as a reference, so that the document conveyance direction and the reading line (main scanning) are kept perpendicular, and the document is not read obliquely.
[0067]
In addition, since the guide 82 and the white plate 61 also have a unit configuration integrally with the reading unit, the document can be stably maintained without floating from the reading surface, and image distortion and the like can be prevented.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an image reading apparatus and a document feeder according to an embodiment.
FIG. 2 is a diagram illustrating a configuration of an image forming apparatus according to the embodiment.
FIG. 3 is a diagram illustrating a drive system of the document feeder according to the embodiment.
FIG. 4 is a detailed view of a document reading unit of the document feeder according to the embodiment.
FIG. 5 is a plan view of a document reading unit of the document feeder according to the embodiment.
FIG. 6 illustrates a configuration of another image reading apparatus and a document feeder according to another embodiment.
FIG. 7 illustrates a configuration of another image reading apparatus and a document feeder according to another embodiment.
FIG. 8 is a block diagram showing a circuit configuration of a control device of the document feeder according to the embodiment.
[Explanation of symbols]
2 Document processing device 3 Platen 4 Document tray 10 Paper discharge tray 12 Registration roller 18 Paper discharge roller 22 Read roller 23 Read discharge roller 24 Platen roller 60 Second reading unit 61 White plate 82 Guide section (holding member)
83 Holder (holding member)
84 fixing part (holding member)
160 First reading unit 161 Flow reading platen 150 Reader unit 300 Printer unit

Claims (3)

A sheet transport unit that transports the sheet on which the image is formed,
A first image reading unit that reads an image of the first surface of the sheet conveyed by the sheet conveying unit,
The first image reading unit includes:
A sheet receiving member,
A first image reading unit that reads an image of a first surface of the sheet passing through the surface of the sheet receiving member; and
A sheet conveying unit and a second image reading unit configured to read an image on a second surface of the sheet conveyed by the sheet conveying unit; holding the second image reading unit; An image reading apparatus, comprising: a holding unit that changes and adjusts and fixes. 2. The sheet conveying apparatus according to claim 1, wherein the second reading unit integrally forms a sheet conveying guide near the reading unit. 3. The sheet conveying apparatus according to claim 1, wherein the second reading unit is removable and replaceable.

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