JP2005167846A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image scanner capable of suppressing adhesion of dirt and causing of damage to a white reference member used for shading correction and acquiring shading data under the same condition under which an image of an original is read. <P>SOLUTION: A dichotomic roll 61 is located in opposition to a CIS 50 for reading an image of an original carried on a carrying path. An outer circumferential face 61a of a circular-arc shape is formed to an outer circumference of the dichotomic roll 61 and a white reference member 63 is fitted to part of the region of the roll 61. In the case of reading the original, the dichotomic roll 61 is rocked to expose the outer circumferential face 61a to the carrying path and in the case of acquiring the shading data, the dichotomic roll 61 is rocked to expose the white reference member 63 to the carrying path. In this case, the white reference member 63 is configured so that a white reference face 63a of the white reference member 63 is coincident with a read position R of the original in the optical axis direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus that reads an image on an original, and more particularly, to an image reading apparatus having a white reference for performing shading correction.

2. Description of the Related Art Conventionally, an image reading apparatus that automatically reads image information of a document is used as a reading apparatus such as a copying machine or a facsimile or a scanner for computer input. In this type of image reading apparatus, light is applied to a document using a light source extending in a direction orthogonal to the document transport path, and reflected light reflected from the irradiated document is received by an image sensor. Reading the image on the manuscript.
In such an image reading apparatus, there may occur a situation in which the amount of light emitted from the light source varies depending on the position in the direction orthogonal to the document transport path, or the amount of light of the light source varies with time. When such variations or fluctuations in the amount of light occur, for example, when a document on which a halftone image is uniformly formed is read, the output image signal is non-uniform with variations depending on the amount of light from the light source. End up.

  Therefore, a white member (white reference portion) extending in a direction orthogonal to the document transport path is disposed opposite to the light irradiation direction of the light source, and light is emitted from the light source to the white reference portion, A technique is widely used in which reflected light is received by an image sensor and correction data (shading data) corresponding to an illuminance distribution in a direction orthogonal to the document conveyance direction is acquired in advance (Patent Document 1). reference.). Then, during actual document reading operation, the image data obtained by reading the document is corrected using the shading data (shading correction) to remove unevenness due to the light quantity distribution of the light source.

JP 2001-313794 A (page 3-4, FIG. 3)

By the way, in such an image reading apparatus, since the conveyed document comes into contact with the white reference portion, dirt on the document such as toner or ballpoint pen ink tends to adhere to the white reference portion. Further, since the conveyed document rubs against the white reference portion, the white reference portion is easily damaged. If the white reference portion is contaminated or scratched in this way, there will be unevenness in the white reference portion in the direction perpendicular to the document transport path. Even if correction is performed using the obtained shading data, unevenness occurs in the obtained image data.
To solve this problem, in the technique described in Patent Document 1, the white reference portion is formed on the surface of the rotatable roll member, and when the shading correction is performed, the roll member is rotated so that the white reference portion is placed in the document transport path. When the document is read (during conveyance), the roll member is rotated so that the guide surface other than the white reference portion is exposed in the document conveyance path.

  However, in the technique described in Patent Document 1, the white reference portion is located farther than the reading position of the document as viewed from the image sensor, and the distance between the image sensor and the white reference portion is the focal depth distance of the image sensor. Therefore, there is a problem that an image obtained by reading a document is blurred.

  Further, in Patent Document 1, reading is performed while pressing a document against a reading unit on which an image sensor is mounted, and the reading unit itself is easily contaminated or scratched. Another problem is that image defects such as streaks tend to occur in the read image data.

The present invention has been made to solve such a technical problem, and an object of the present invention is to suppress adhesion and damage of a white reference used for shading correction and to read an image of a document. It is to be able to obtain shading data under the same conditions as in the case.
Another object is to suppress blurring of the read image.
Yet another object is to suppress show-through in the read image.

  For this purpose, an image reading apparatus to which the present invention is applied includes a conveyance path through which a document is conveyed, a reading unit that reads an image of a document conveyed through the conveyance path, and a reading unit that faces the reading unit via the conveyance path. The white reference member provided at the site to be scanned and the white reference member retracted from the reading position of the original by the reading unit when reading the image of the original by the reading unit, and the original when the shading data is acquired by the reading unit And a drive unit that advances the white reference member to the reading position in the optical axis direction.

  Here, the document reading position by the reading unit may be a focal position of a lens provided in the reading unit. The reading unit may include a CIS (Contact Image Sensor) sensor. Further, the reading unit may include a light source configured by arranging a large number of LEDs (Light Emitting Diodes). The reading unit can read the image of the document while being separated from the document.

  From another viewpoint, the image reading apparatus to which the present invention is applied includes a conveyance path through which the document is curved and conveyed, a reading unit that reads an image on the document from the inside of the curved document, and a curve. A guide member that is guided while being abutted on the outside of the document to be moved, and a guide member that is downstream of the guide member in the document transport direction and moves between a reading position by the reading unit and a retracted position for saving from the reading position. And a white reference surface which can be arranged.

  Here, the document reading position by the reading unit may be a position through which the surface of the document transported through the transport path passes. Further, the retracted position of the white reference surface may be a position where the white reference surface is not exposed to the conveyance path. Further, the reading unit can read the image of the document as a color image. And it can be characterized by further providing a cleaning member for cleaning the white reference plane.

  From another point of view, an image reading apparatus to which the present invention is applied includes a conveyance path through which a document is conveyed, a reading unit that reads an image of a document conveyed through the conveyance path, and a reading unit via the conveyance path. And a swinging member having an arcuate outer peripheral surface and a swing member formed on the outer peripheral surface of the swinging member and facing the reading position of the document by the reading unit. And a white reference member having a white reference surface whose height coincides with the reading position.

  Here, the reading position of the document by the reading unit can be characterized in that it is located downstream of the top position on the outer peripheral surface of the swing member in the document transport direction. In addition, a predetermined gap may be formed between the original reading position and the outer peripheral surface of the swing member at the original reading position by the reading unit. Further, the swing shaft of the swing member may be arranged on the upstream side in the document transport direction with respect to the extension line of the optical axis passing through the document reading position by the reading unit.

  Further, from another point of view, the image reading apparatus to which the present invention is applied includes a conveyance path in which the document is curved and conveyed, and a first reading that reads the first surface of the document from the outside of the curved portion of the conveyance path. A second reading unit that reads the second surface of the document from the inside of the curved portion of the conveyance path, a guide member that is disposed outside the curved portion of the document so as to face the second reading unit, On the downstream side of the document transport direction, when the image of the document is read by the reading unit, the document is retracted from the reading position of the document by the reading unit, and when the shading data is acquired by the reading unit, the document is moved to the reading position of the document. And a white reference member.

  Here, the first reading unit includes a first image sensor that reads the reflected light of the document via the reduction optical system, and the second reading unit transmits the reflected light of the document more than the first image sensor. It can be characterized by having a second image sensor that reads from a close position.

  According to the present invention, it is possible to suppress the adhesion and damage of dirt to the white reference used for shading correction, and to acquire shading data under the same conditions as when reading an image of a document.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the accompanying drawings.
—Embodiment 1—
FIG. 1 is a diagram showing an image reading apparatus to which the present embodiment is applied. This image reading apparatus is roughly divided into a document feeding device 10 that sequentially conveys documents from a stacked document bundle, a scanner device 70 that reads an image by scanning, and a processing device 80 that processes the read image signal. Is done.

  The document feeder 10 includes a document tray 11 on which a bundle of documents composed of a plurality of documents is stacked, and a tray lifter 12 that raises and lowers the document tray 11. Further, a nudger roll 13 that conveys the original on the original tray 11 raised by the tray lifter 12, a feed roll 14 that conveys the original conveyed by the nudger roll 13 further downstream, and an original supplied by the nudger roll 13. Are provided with a retard roll 15. In the first transport path 31 where the original is first transported, a takeaway roll 16 that transports the originals that are being fed one by one to the downstream roll, transports the original to the further downstream roll, and creates a loop. The pre-registration roll 17 to be performed, the rotation is resumed at the timing after stopping once, the registration roll 18 for supplying the original while adjusting the registration to the original reading unit, the platen roll 19 for assisting the conveyance of the original being read, An out-roll 20 is provided for conveying the read original further downstream. The first transport path 31 includes a baffle 41 that rotates about a fulcrum according to the loop state of the document being transported. Further, a CIS (Contact Image Sensor) 50 which is a reading unit (second reading unit) in the present embodiment is provided between the platen roll 19 and the out-roll 20.

  A second transport path 32 and a third transport path 33 are provided on the downstream side of the out-roll 20, a transport path switching gate 42 for switching between these transport paths, a discharge tray 40 for stacking documents that have been read, and a discharge tray A first discharge roll 21 that discharges the original document 40 is provided. In addition, an inverter roll 22 and an inverter pinch roll 23 that are provided in the fourth transport path 34 and the fourth transport path 34 for switching back the document that has passed through the third transport path 33 and actually switch back the document, The document switched back by the fourth transport path 34 is again guided to the first transport path 31 including the pre-registration roll 17 and the like, and the document switched back by the fourth transport path 34 is discharged to the discharge tray 40. The transport paths of the second discharge roll 24, the fifth transport path 35, and the sixth transport path 36 that are provided in the sixth transport path 36 and the sixth transport path 36 and transport the inverted document to the first discharge roll 21. An exit switching gate 43 for switching is provided.

  The nudger roll 13 is lifted up and held at the retracted position during standby, and descends to the nip position (original conveyance position) during conveyance of the document to convey the uppermost document on the document tray 11. The nudger roll 13 and the feed roll 14 convey a document by connecting a feed clutch (not shown). The pre-registration roll 17 makes a loop by abutting the leading end of the document against the stopped registration roll 18. In the registration roll 18, when the loop is created, the leading edge of the document bitten by the registration roll 18 is returned to the nip position. When this loop is formed, the baffle 41 opens around the fulcrum and functions so as not to disturb the document loop. Further, the take away roll 16 and the pre-registration roll 17 hold a loop during reading. By this loop formation, the read timing can be adjusted, and the skew associated with the document conveyance at the time of reading can be suppressed, and the alignment adjustment function can be enhanced. The stopped registration roll 18 starts rotating in accordance with the start timing of reading, and is pressed against the second platen glass 72B (described later) by the platen roll 19 to read the image data from the lower surface direction.

  The conveyance path switching gate 42 switches so that the document passing through the out-roll 20 is guided to the second conveyance path 32 and discharged to the discharge tray 40 at the end of reading one-sided document and at the same time when reading both-side documents simultaneously. It is done. On the other hand, the transport path switching gate 42 is switched so as to guide the document to the third transport path 33 in order to invert the document when the double-sided document is sequentially read. The inverter pinch roll 23 is retracted with the feed clutch (not shown) turned off during sequential reading of the double-sided document to open the nip, and guides the document to the inverter path (fourth conveyance path 34). Thereafter, the inverter pinch roll 23 is nipped, the original to be inverted by the inverter roll 22 is guided to the pre-registration roll 17, and the original to be reversed is conveyed to the second discharge roll 24 in the sixth conveyance path 36.

  A scanner device 70 as a first reading unit can include the above-described document feeding device 10, and the document feeding device 10 is supported by a device frame 71, and an image of a document conveyed by the document feeding device 10. Reading is in progress. The scanner device 70 includes a first platen glass 72A for placing a document to be read in a stationary state on a device frame 71 forming a casing, and a light for reading a document being conveyed by the document feeder 10. A second platen glass 72 </ b> B is formed to form the opening.

  The scanner device 70 is stationary under the second platen glass 72B and scans the entire first platen glass 72A to read an image, and the light obtained from the full rate carriage 73 is image-coupled. A half-rate carriage 75 is provided to provide a portion. The full-rate carriage 73 includes an illumination lamp 74 that irradiates light on the original and a first mirror 76A that receives reflected light obtained from the original. Further, the half-rate carriage 75 is provided with a second mirror 76B and a third mirror 76C that provide the light obtained from the first mirror 76A to the imaging unit. Further, the scanner device 70 includes an imaging lens 77 that optically reduces the optical image obtained from the third mirror 76C, and a CCD (Charge Coupled Device) that photoelectrically converts the optical image formed by the imaging lens 77. ) An image sensor 78 and a drive substrate 79 having a CCD image sensor 78 are provided, and an image signal obtained by the CCD image sensor 78 is sent to the processing device 80 through the drive substrate 79.

  Here, first, when reading an image of a document placed on the first platen glass 72A, the full rate carriage 73 and the half rate carriage 75 move in the scanning direction (arrow direction) at a ratio of 2: 1. . At this time, the light of the illumination lamp 74 of the full rate carriage 73 is irradiated on the surface to be read of the document, and the reflected light from the document is reflected in the order of the first mirror 76A, the second mirror 76B, and the third mirror 76C. Then, it is guided to the imaging lens 77. The light guided to the imaging lens 77 forms an image on the light receiving surface of the CCD image sensor 78. The CCD image sensor 78 is a one-dimensional sensor and processes one line at the same time. When reading of one line in this line direction (main scanning direction of scanning) is completed, the full-rate carriage 73 is moved in a direction (sub-scanning direction) orthogonal to the main scanning direction to read the next line of the document. By executing this over the entire document size, reading of one page of the document is completed.

  On the other hand, the second platen glass 72B is constituted by a transparent glass plate having a long plate-like structure, for example. A document conveyed by the document feeder 10 passes over the second platen glass 72B. At this time, the full-rate carriage 73 and the half-rate carriage 75 are stopped at the solid line positions shown in FIG. First, the reflected light of the first line of the document that has passed through the platen roll 19 of the document feeder 10 is imaged by the imaging lens 77 via the first mirror 76A, the second mirror 76B, and the third mirror 76C. An image is read by the CCD image sensor 78 which is the first sensor in the present embodiment. That is, after one line in the main scanning direction is simultaneously processed by the CCD image sensor 78 which is a one-dimensional sensor, the next line in the main scanning direction of the original conveyed by the original feeding device 10 is read. After the leading edge of the document reaches the reading position of the second platen glass 72B, the document passes through the reading position of the second platen glass 72B, whereby reading of one page is completed in the sub-scanning direction.

  In the present embodiment, the full-rate carriage 73 and the half-rate carriage 75 are stopped, and the first platen glass 72B is used to read the first surface of the document by the CCD image sensor 78. It is possible to read the second side of the original by the CIS 50 (meaning that it is not coincident but the same as when the same original is conveyed). That is, using the CCD image sensor 78 that is the first image sensor and the line sensor 54 that is the second image sensor, the images on both the front and back sides of the original are read by the single conveyance of the original to the conveyance path. Is possible.

  FIG. 2 is a diagram for explaining a reading structure using the CIS 50. As shown in FIG. 2, the CIS 50 is provided between the platen roll 19 and the out roll 20. One side (first side) of the original is pressed against the second platen glass 72B, and the image on the first side is read by the CCD image sensor 78. On the other hand, in the CIS 50, an image on one side (second side) is read from the other side facing through a conveyance path for conveying a document. The CIS 50 includes a cover glass 51, an LED (Light Emitting Diode) 52 as a light source that irradiates the second surface of the document through the cover glass 51, and a lens array that collects reflected light from the LED 52. And a line sensor 54 that is an image sensor that reads light collected by the Selfoc lens 53. As the line sensor 54, a CCD, a CMOS sensor, a contact sensor, or the like can be used, and an image with an actual width (for example, A4 longitudinal width 297 mm) can be read. In the CIS 50, since the image is captured using the SELFOC lens 53 and the line sensor 54 without using the reduction optical system, the structure can be simplified, the housing can be downsized, and the power consumption can be reduced. Can be reduced. The LED 52 is configured by arranging a plurality of LED elements, which are point light sources, in parallel. In the present embodiment, the CIS 50 can read the original as a color image. The LED 52 is combined with LED light sources of three colors R (red), G (green), and B (blue), and the line sensor 54 is RGB3. A set of three rows of sensors for color is used.

  Further, when the image is read by the CIS 50, a control member 55 extending from the casing of the CIS 50 and an abutting member 60 as a guide member for abutting the paper pressed by the control member 55 are provided on the conveyance path constituting the reading unit. Yes. Further, on the downstream side of the abutting member 60, a half-moon roll 61 as a swinging member is disposed opposite to the CIS 50 and the conveyance path, and a guide member 62 is provided on the downstream side of the half-moon roll 61. . The control member 55, the abutting member 60, and the meniscus roll 61 are arranged in the direction of the conveyance path from the front side to the rear side of the document feeder in a direction orthogonal to the document conveyance path (that is, from the front to the rear of the document feeder). It is provided corresponding to the position.

  Here, the half-moon roll 61 has an arc-shaped outer peripheral surface 61a colored, for example, in light gray, and a white reference member 63 is attached to an end of the outer peripheral surface. The white reference member 63 is also provided corresponding to the position of the conveyance path from the front surface to the rear surface of the document feeder in a direction orthogonal to the document conveyance path (that is, from the front surface to the rear surface of the document feeder). ing. The meniscal roll 61 is attached so as to be swingable about an axis, and can be swung by a solenoid 64 as a drive unit. Note that a brush 65 that can come into contact with the white reference member 63 is attached to the half-moon roll 61 when the abutting member 60 is opposed to the half-moon roll 61. The brush 65 functions as a cleaning member for the white reference member 63 as will be described later.

  Since the CIS 50 employs the SELFOC lens 53 as an optical imaging lens, the depth of focus (field of view) is shallow. FIG. 3 is a diagram for explaining the depth of focus as the lens imaging performance. FIG. 3 shows an MTF (Modulation Transfer Function) having a lens depth (7.8 Lp / mm) using a reduction optical system such as the scanner device 70 according to the present embodiment, and a lens depth using a SELFOC lens 53 ( An example of MTF of 6 Lp / mm) is shown. This “Lp / mm” is a value indicating how many ladder patterns of black and white exist within 1 mm. The MTF expresses how the spatial information (contrast) of a subject is faithfully reproduced from the low frequency range (coarse manuscript) to the high frequency range (fine stripes) using frequency characteristics. . The vertical axis in FIG. 3 indicates MTF (%), and the horizontal axis indicates a state in which the focal point is the best on the platen glass or the like, and a state in which the distance is 1 mm.

  For example, if the target is MTF of 20% or more when reading a document, when the scanner device 70 according to the present embodiment is used, a constant focus is achieved even at about ± 4 mm, and the depth of field can be increased. On the other hand, when the SELFOC lens 53 is used, when the target is MTF of 20% or more, the depth of field is as shallow as about ± 0.3 mm, which is about 1/13 or less than that when the scanner device 70 is used. It is a depth. That is, when reading with the CIS 50 in the present embodiment, it is required to set the reading position of the document within a predetermined narrow range.

  Therefore, in the present embodiment, the control member 55 is provided, and the document is pressed against the abutting member 60 by the control member 55 and conveyed, so that the posture of the document between the platen roll 19 and the out-roll 20 can be stabilized. Configured to be controllable. The “paper movement B” indicated by the solid line arrow in FIG. 2 indicates the paper movement when the control member 55 is not present, and the “paper movement A” indicated by the two-dot chain line arrow is the control member 55. This shows the movement of the paper when the is provided. In the “paper movement A”, it can be understood that the document is pressed against the abutting member 60 and conveyed. That is, by reading the document conveyed by the control member 55 while being pressed against the abutting member 60 and the half-moon roll 61, the sweetness of the focus when the CIS 50 having a shallow depth of field is used is improved. ing.

Next, the processing device 80 shown in FIG. 1 will be described.
FIG. 4 is a block diagram for explaining the processing device 80. The processing device 80 to which this embodiment is applied is large and controls the signal processing unit 81 that processes image information obtained from the sensors (CCD image sensor 78 and CIS 50), the document feeder 10 and the scanner device 70. And a control unit 90. The signal processing unit 81 includes an AFE (Analog Front End) 82 that performs analog signal processing, an ADC (Analog to Digital Converter) 83 that converts an analog signal into a digital signal, and various types of shading correction and offset correction for the digital signal. A digital processing unit 84 that performs processing is provided, and the digital signal processed by the digital processing unit 84 is output to a host system, for example, as image information to a printer.

  On the other hand, the control unit 90 includes an image reading control 91 that controls the entire document feeding device 10 and the scanner device 70, including various double-sided scanning control and single-sided scanning control, a CCD image sensor 78 that is a first sensor, and The CCD / CIS control 92 for controlling the CIS 50, the lamp control 93 for controlling the LED 52 of the CIS 50 and the illumination lamp 74 of the full rate carriage 73 in accordance with the reading timing, the motor in the scanner device 70 and the solenoid 64 described above are turned on / off. A scan control 94 for controlling the scanning operation of the full rate carriage 73 and the half rate carriage 75, motor control in the document feeder 10, various roll operations, feed clutch operations, gate switching operations, and the like are controlled. And a conveying mechanism control 95. From these various controls, control signals are output to the document feeder 10 and the scanner device 70, and these operations can be controlled based on the control signals. The image reading control 91 sets a reading mode based on a control signal from the host system, a sensor output detected in the automatic selection reading function, a selection from the user, and the like, and controls the document feeder 10 and the scanner device 70. I have control.

  Here, in the present embodiment, when an image is read by conveying the document by the document feeder 10, the scanner device 70 (CCD image sensor 78) is used for the document conveyed to the platen roll 19 through the second platen glass 72B. And can be read using the CIS 50 provided in the document feeder 10. However, as described above, the depth of focus differs between reading by the CCD image sensor 78 using the mechanism of the scanner device 70 and reading using the SELFOC lens 53 of the CIS 50, and the resolution characteristics. Will cause a difference. In particular, when a color image such as a photograph is read, color matching becomes difficult when both are read, and the image quality obtained by reading both is different. Therefore, in this embodiment, a plurality of reading modes are prepared, and an optimum mode can be selected based on the setting state of the apparatus, the type of document, the user's selection, and the like.

  FIG. 5 is a flowchart showing an example of processing executed by the image reading control 91 shown in FIG. In the image reading control 91, first, it is determined whether or not the conveyed document is a single-sided document (step 101). This determination is made by, for example, selection from a user using a control panel (not shown) provided on the scanner device 70, or, for example, when the automatic selection reading function is working, the first conveyance before image reading. It can be recognized by sensors (not shown) provided on both sides of the conveyance path on the path 31. In addition, a request from the host system or a selection from the user via a network or the like can be considered. If it is determined in step 101 that the document is a single-sided original, single-sided reading is performed by one pass (one-time original conveyance pass without using a reverse pass) (step 102). In this one-pass single-sided reading, either the reading by the CCD image sensor 78 or the reading by the CIS 50 may be selected. However, in order to realize higher-quality image reading, the reading by the CCD image sensor 78 is selected. It is preferable to do. In such a case, the document tray 11 is placed so that there is a single-sided document portion facing upward and the first page of the document comes up, and the document is transported from the first page and sequentially read.

  If the original is not a single-sided original in step 101, that is, if it is a double-sided original, it is determined whether the original is a white / black original (step 103). The determination in step 103 is determined by the selection from the user or the automatic selection reading function as in step 101. There are cases where the user desires white / black reading even for a color original. When white / black reading is not performed, that is, when color reading is performed, it is determined whether or not image quality is important (step 104). For example, in the case of a color image such as a color photograph or a pamphlet, image quality is generally more important than productivity for increasing the reading speed. Such a determination is also made based on user settings. If it is determined in this step 104 that the image quality is important, double-sided reading by the reverse pass, which is the first double-sided reading mode, is executed (step 105). That is, without reading by the CIS 50, the first surface of the document and the second surface of the document are both read by the CCD image sensor 78 as the first sensor. As a result, both the first side of the original and the second side of the original can be read on both sides with high image quality using the reading means having a deep focal depth.

  On the other hand, when white / black reading is performed in step 103 or when a color image output is required in step 104, for example, when subtle shades such as business colors are not emphasized, plus one color If the image quality is not so important and other factors such as productivity are important, such as in the case of (including other colors such as red and blue in addition to black), the second duplex scanning The mode is simultaneous reading on both sides by one pass without using the reverse pass (step 106). That is, the first surface is read by the CCD image sensor 78 as the first sensor, and the second surface is read by the CIS 50 in the same transport path during this transport path. As a result, it is not necessary to transport the document twice to the same reading unit, the document reading speed can be improved, and the transport path is simplified, so that document transportation troubles such as document jamming (JAM) can be prevented. Can be suppressed. As described above, “simultaneous reading” does not necessarily mean a case where they coincide with each other in time, but means that both sides are read almost simultaneously in one pass.

  Note that the processing flow shown in FIG. 5 is simplified, and in the case of reading a black and white original in double-sided original reading, double-sided simultaneous reading in step 106 is executed, and in the case of a color original, the reverse path in step 105 is sequentially performed. It is also possible to configure to read a document. Also, these modes can be mixed and used according to the type of document surface.

Next, a document transport method in each document reading mode will be described with reference to FIGS.
6 (a) and 6 (b) show the document path in the single-sided reading mode by one pass shown in step 102 of FIG. 5 and the second double-sided reading mode which is double-sided simultaneous reading by one pass shown in step 106. FIG. As shown in FIG. 6A, the documents placed on the document tray 11 are sequentially supplied to the first conveyance path 31 by the nudger roll 13, the feed roll 14, the retard roll 15, and the takeaway roll 16. The As shown in FIG. 6B, the supplied document is moved to the second conveyance path 32 by the conveyance path switching gate 42 via the reading section of the platen roll 19 and the reading section of the CIS 50, and the discharge tray 40. Are sequentially discharged. In the case of single-sided reading, reading is performed using the CCD image sensor 78 of the scanner device 70 shown in FIG. However, as described above, single-sided reading using the CIS 50 is also possible. In the case of simultaneous reading on both sides by one pass, the first surface is read using the CCD image sensor 78 of the scanner device 70, and the second surface is read using the CIS 50 during the same conveyance. As a result, it is possible to read both sides of the document by one document pass.

  FIGS. 7A to 7D are diagrams for explaining the double-sided reading by the reverse path shown in step 105 of FIG. 5, that is, the first double-sided reading mode. As shown in FIG. 7A, the originals placed on the original tray 11 are sequentially supplied to the first transport path 31 and the platen roll using the CCD image sensor 78 of the scanner device 70 shown in FIG. Reading is performed from below at 19 locations. Then, the transfer path switching gate 42 moves to the fourth transfer path 34 via the third transfer path 33. The document that has completely passed through the third conveyance path 33 is switched back by the inverter roll 22 and the inverter pinch roll 23 and supplied to the fifth conveyance path 35 as shown in FIG. 7B.

  The document supplied to the fifth conveyance path 35 is again supplied to the first conveyance path 31. Then, as shown in FIG. 7C, the original is read from below by the CCD image sensor 78 of the scanner device 70. At this time, the document is in an inverted state from the case shown in FIG. 7A, and the second side that is different from the first side is read. The original on which the second side has been read is in an inverted state. If the original is discharged to the discharge tray 40 as it is, the page order of the loaded original after reading will be out of order. Therefore, as shown in FIG. 7C, the document whose second surface has been read is moved to the fourth transport path 34 via the third transport path 33 using the transport path switching gate 42. The original supplied to the fourth transport path 34 and completely passing through the exit switching gate 43 is discharged to the discharge tray 40 by the exit switching gate 43 via the sixth transport path 36 as shown in FIG. Is done. This makes it possible to align the page order of the original after reading in the first double-sided reading mode in which images on both sides of the original are sequentially read.

Next, the position where the half moon roll 61 is disposed and the operation thereof will be described in detail.
FIG. 8 shows an enlarged view of the vicinity of the half moon roll 61 and the CIS 50. FIG. 8 shows the arrangement state of the half-moon roll 61 during the document reading operation. At this time, the half-moon roll 61 is arranged by the solenoid 64 (see FIG. 2) so that the outer peripheral surface 61a faces the reading position R by the CIS 50. On the other hand, the white reference member 63 attached to the outer peripheral surface 61a of the half moon roll 61 is in a position retracted from the conveyance path. In the present embodiment, the swing center X of the half-moon roll 61 is disposed offset to the upstream side in the document transport direction with respect to the document reading position R by the CIS 50. As a result, the reading position R of the document is positioned on the downstream side in the document transport direction from the top position C of the outer peripheral surface 61a of the meniscal roll 61 that protrudes most on the transport path side. Here, the reading position R of the original is a focus position (focal position) of the Selfoc lens 53 provided in the CIS 50, and not only in the direction of transporting the original but also in the optical axis direction of light passing through the Selfoc lens 53. It is determined uniquely.

  And in this Embodiment, the radius (distance of the rocking | swiveling center X and the outer peripheral surface 61a) of the half-moon roll 61 is set to 25 mm. The distance D between the line α passing through the swing center X of the meniscal roll 61 and the top position C and the extension line β of the optical axis passing through the document reading position R is set to 2.1 mm. Further, an angle θ formed by a line α passing through the swing center X of the half-moon roll 61 and the top position C and a line γ passing through the swing center X of the half-moon roll 61 and the document reading position R is set to 85 °. Is done. As a result, the gap G between the document reading position R and the outer peripheral surface 61a of the meniscal roll 61 on the extension line β of the optical axis passing through the document reading position R is 0.1 mm.

  Further, in the present embodiment, the conveyance path in the vicinity of the abutting member 60 is curved, and the document is conveyed in a curved state. The CIS 50 is disposed inside the document conveyed in a curved manner, and the abutting member 60 and the half moon roll 61 are disposed outside the document conveyed in a curved manner. As described above, the control member 55 is attached to the CIS 50 on the conveyance path side. For this reason, the conveyed document is conveyed in a state where it is in contact with the abutting member 60, or in a state where it is separated from the cover glass 51 provided in the CIS 50 from another viewpoint. Therefore, there is no situation in which the original of the original adheres to the cover glass 51 or the cover glass 51 is rubbed and damaged by the original.

  When the original reading operation is actually performed, the original conveyed while abutting against the abutting member 60 is located at the top position C of the outer peripheral surface 61a of the half-moon roll 61 as indicated by the movement A of the paper. On the other hand, at the document reading position R, the document is transported in a state of being separated (floating) from the outer peripheral surface 61a of the meniscal roll 61. Here, since the top position C is rubbed by the conveyed document, the outer peripheral surface 61a corresponding to the top position C is soiled or damaged by adhesion of dust or toner attached to the document, ink of a ballpoint pen, correction fluid, or the like. However, since the document does not come into contact with the outer peripheral surface 61a of the meniscal roll 61 corresponding to the reading position R of the document, such contamination cannot occur. Therefore, in the present embodiment, when the original is read by the CIS 50, the original can be floated at the original reading position R by using the half-moon roll 61, and disposed on the back side of the original reading surface. The show-through caused by the dirt adhering to the member can be prevented. In this embodiment, the outer peripheral surface 61a of the half-moon roll 61 is colored light gray. However, if it is colored, for example, black, the show-through caused by the image formed on the back side of the reading surface of the document is eliminated. It is also possible to prevent.

  On the other hand, FIG. 9 shows the arrangement state of the half-moon roll 61 during the shading data acquisition operation. During the shading data acquisition operation, the half moon roll 61 is rotated about 90 ° clockwise by the solenoid 64 (see FIG. 2), and the white reference member 63 formed on the outer circumferential surface 61a of the half moon roll 61 is read by the CIS 50. Arranged (advanced) to face R. In particular, in the present embodiment, the white reference surface 63a of the white reference member 63 is at the same height as the document surface indicated by the paper movement A, that is, the white reference surface 63a and the document reading position R coincide. It is supposed to be. Thus, in the present embodiment, it is possible to acquire shading data at the reading position R of the document by the CIS 50, that is, to acquire shading data under the same conditions as when reading an image of the document. Further, since the white reference member 63 is exposed to the conveyance path only during the shading data acquisition operation in which the document is not conveyed, the white reference surface 63a of the white reference member 63 is not contaminated or damaged by the document. . Furthermore, since the reading position of the white reference surface 63a and the reading position of the conveyed document can be substantially matched, the read image does not blur. After the shading data is acquired, the half-moon roll 61 is rotated about 90 ° counterclockwise by the solenoid 64 (see FIG. 2), and the state shown in FIG. 8 is restored.

  In the present embodiment, the abutting member 60 is provided with a brush 65 as a cleaning member, and the white reference surface of the white reference member 63 provided on the half-moon roll 61 as the half-moon roll 61 swings. 63 a is cleaned by the brush 65. As a result, the white reference surface 63a of the white reference member 63 can be kept clean at all times, and the shading data acquired by reading the white reference surface 63a of the white reference member 63 with the CIS 50 is good over a long period of time. can do.

-Embodiment 2-
The present embodiment is substantially the same as the first embodiment, but the white reference member is moved linearly. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 10 is a diagram for explaining a reading structure using the CIS 50. In the present embodiment, instead of the half-moon roll 61 used in the first embodiment, the slide member 100 is disposed at a position facing the CIS 50.

  Here, the slide member 100 includes, for example, a main body portion 101 having a curved surface 101a as an arcuate outer peripheral surface colored in light gray, and a base portion 102 attached to a side portion of the main body portion 101 on the guide member 62 side. And a white reference member 103 attached to the upper portion of the base portion 102. The white reference member 103 is also provided corresponding to the position of the conveyance path from the front to the rear of the document feeder in a direction orthogonal to the document conveyance path (that is, from the front to the rear of the document feeder). ing. Further, the slide member 100 is slidably attached in the direction of the arrow in the figure, and can be moved by a solenoid 104 as a drive unit.

  FIG. 11 shows an arrangement state of the slide member 100 during a document reading operation. At this time, the slide member 100 is disposed by the solenoid 104 (see FIG. 10) so that the curved surface 101 a of the main body 101 faces the reading position R by the CIS 50. Also in the present embodiment, the document reading position R is located on the downstream side in the document transport direction from the top position C of the curved surface 101a of the slide member 100 that protrudes most in the transport path.

  When the original reading operation is actually performed, the curved surface formed on the main body 101 of the slide member 100 is the original conveyed while being abutted against the abutting member 60 as indicated by the movement A of the paper. While contacting the top position C of 101a, the original reading position R is conveyed away from the curved surface 101a formed on the main body 101 of the slide member 100 (floating state). As in the first embodiment, the vertex position C is rubbed by the conveyed document, so that the curved surface 101a corresponding to the vertex area C is soiled by adhesion of dust or toner attached to the document, ink of a ballpoint pen, correction fluid, or the like. However, since the original does not come into contact with the curved surface 101a corresponding to the reading position R of the original, such dirt cannot be attached. Therefore, in the present embodiment, when the original is read by the CIS 50, the original is floated at the original reading position R by using the slide member 100, thereby being arranged on the back side of the original reading surface. See-through caused by dirt adhering to the member can be prevented. In the present embodiment, the curved surface 101a of the slide member 100 is colored light gray. However, as in the first embodiment, for example, if it is colored black, it is formed on the back side of the original reading surface. It is also possible to prevent show-through caused by an image.

  On the other hand, FIG. 12 shows an arrangement state of the slide member 100 during the shading data acquisition operation. During the shading data acquisition operation, the slide member 100 is slid to the abutting member 60 side by the solenoid 104 (see FIG. 10), and the white reference surface 103a of the white reference member 103 formed on the base portion 102 of the slide member 100 is moved. It is arranged (advanced) so as to face the reading position R by the CIS 50. In particular, in the present embodiment, as in the first embodiment, the white reference surface 103a of the white reference member 103 has the same height as the document surface indicated by the paper movement A, that is, the white reference surface 103a and the document. Is set to coincide with the reading position R. Thus, in the present embodiment, it is possible to acquire shading data at the reading position R of the document by the CIS 50, that is, to acquire shading data under the same conditions as when reading an image of the document. Further, the white reference member 103 is exposed to the conveyance path only during the shading data acquisition operation in which the document is not conveyed, and is otherwise hidden from the conveyance path by the guide member 62. Therefore, the white reference surface 103a of the white reference member 103 is hidden. There will be no situation where the document is soiled or damaged by the manuscript. Furthermore, since the reading position of the white reference surface 103a and the reading position of the conveyed document can be substantially matched, the read image does not blur. After the shading data is acquired, the slide member 100 is slid to the guide member 62 side by the solenoid 104 (see FIG. 10) and returns to the state shown in FIG.

  In the present embodiment, for example, if a brush or the like is provided at a portion of the guide member 62 facing the white reference member 103, the white reference surface 103a of the white reference member 103 is cleaned as in the first embodiment. can do. In this case, the white reference surface 103a of the white reference member 103 can be kept clean at all times, and the shading data acquired by reading the white reference surface 103a of the white reference member 103 with the CIS 50 is good. can do.

It is the figure which showed the image reading apparatus with which this Embodiment is applied. In Embodiment 1, it is a figure for demonstrating the reading structure using CIS. It is a figure for demonstrating a depth of focus as lens imaging performance. It is a block diagram for demonstrating a processing apparatus. It is the flowchart which showed an example of the process performed by image reading control. (a), (b) is a figure for demonstrating the original path | pass of the 2nd double-sided reading mode which is the single-sided reading mode by 1 pass, and the double-sided simultaneous reading by 1 pass. (a)-(d) is a figure for demonstrating the double-sided reading by an inversion path | pass. It is a figure which shows the arrangement | positioning state of the half moon roll at the time of the reading operation | movement of a document. It is a figure which shows the arrangement | positioning state of a half moon roll at the time of the acquisition operation of shading data. In Embodiment 2, it is a figure for demonstrating the reading structure using CIS. FIG. 6 is a diagram illustrating an arrangement state of slide members during a document reading operation. It is a figure which shows the arrangement | positioning state of the slide member at the time of the acquisition operation of shading data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Document feeder, 11 ... Document tray, 13 ... Nudger roll, 19 ... Platen roll, 20 ... Out roll, 22 ... Inverter roll, 23 ... Inverter pinch roll, 31 ... First conveyance path, 32 ... Second conveyance , 33 ... third conveyance path, 34 ... fourth conveyance path, 35 ... fifth conveyance path, 36 ... sixth conveyance path, 40 ... discharge tray, 41 ... baffle, 42 ... conveyance path switching gate, 43 ... exit switching Gate: 50 ... CIS (Contact Image Sensor), 51 ... Cover glass, 52 ... LED (Light Emitting Diode), 53 ... Selfoc lens, 54 ... Line sensor, 55 ... Control member, 60 ... Abutting member, 61 ... Half moon Roll, 62 ... Guide member, 63 ... White reference member, 64 ... Solenoid, 65 ... Brush, 70 ... Scanner device, 72A ... First platen glass, 72B ... Second platen glass, 3 ... full rate carriage, 74 ... illumination lamp, 75 ... half rate carriage, 76A ... first mirror, 76B ... second mirror, 76C ... third mirror, 77 ... imaging lens, 78 ... CCD (Charge Coupled Device) image Sensor, 80 ... Processing device, 81 ... Signal processing unit, 90 ... Control unit, 100 ... Slide member, 101 ... Main body, 101a ... Curved surface, 102 ... Base, 103 ... White reference member, 103a ... White reference surface, 104 …solenoid

Claims (16)

A transport path through which the document is transported;
A reading unit for reading an image of a document conveyed along the conveyance path;
A white reference member provided at a portion facing the reading unit via the conveyance path;
When the image of the original is read by the reading unit, the white reference member is retracted from the reading position of the original by the reading unit, and when the shading data is acquired by the reading unit, the optical axis direction of the original An image reading apparatus having a drive unit that advances the white reference member to a reading position.   The image reading apparatus according to claim 1, wherein a reading position of the document by the reading unit is a focal position of a lens provided in the reading unit.   The image reading apparatus according to claim 1, wherein the reading unit includes a CIS (Contact Image Sensor) sensor.   The image reading apparatus according to claim 1, wherein the reading unit includes a light source configured by arranging a large number of LEDs (Light Emitting Diodes).   The image reading apparatus according to claim 1, wherein the reading unit reads an image of the document while being separated from the document. A conveyance path through which the document is curved and conveyed;
A reading unit that reads an image on the document from the inside of the document to be curved;
A guide member that is guided while being abutted against the outside of the document to be curved;
An image reading apparatus having a white reference surface that is disposed downstream of the guide member in the document conveyance direction and is movable between a reading position by the reading unit and a retracted position that is retracted from the reading position.   The image reading apparatus according to claim 6, wherein the reading position of the original by the reading unit is a position through which a surface of the original conveyed along the conveyance path passes.   The image reading apparatus according to claim 6, wherein the retracted position of the white reference surface is a position where the white reference surface is not exposed to the conveyance path.   The image reading apparatus according to claim 6, wherein the reading unit is capable of reading a document image as a color image.   The image reading apparatus according to claim 6, further comprising a cleaning member that cleans the white reference surface. A transport path through which the document is transported;
A reading unit for reading an image of a document conveyed along the conveyance path;
A swinging member that is swingably disposed at a portion facing the reading unit via the transport path and has an arcuate outer peripheral surface;
Image reading having a white reference member formed on the outer peripheral surface of the swinging member and having a white reference surface whose height coincides with the reading position of the document at a position facing the reading position of the document by the reading unit. apparatus.   The image reading apparatus according to claim 11, wherein a reading position of the document by the reading unit is downstream of the top position on the outer peripheral surface of the swing member in the document transport direction.   The image reading apparatus according to claim 11, wherein a predetermined gap is formed between the reading position of the document and the outer peripheral surface of the swing member at the reading position of the document by the reading unit.   12. The image reading according to claim 11, wherein the swinging shaft of the swinging member is disposed upstream of the extension line of the optical axis passing through the reading position of the document by the reading unit in the document transport direction. apparatus. A conveyance path through which the document is curved and conveyed;
A first reading unit that reads the first surface of the document from the outside of the curved portion of the conveyance path;
A second reading unit that reads the second surface of the document from the inside of the curved portion of the conveyance path;
A guide member disposed on the outer side of the curved portion of the document so as to face the second reading unit;
When reading the image of the document by the reading unit on the downstream side of the guide member in the document transport direction, the document is retracted from the reading position of the document by the reading unit and shading data is acquired by the reading unit. Is an image reading apparatus having a white reference member that is advanced to the reading position of the document. The first reading unit includes a first image sensor that reads reflected light of a document via a reduction optical system,
The image reading apparatus according to claim 15, wherein the second reading unit includes a second image sensor that reads reflected light of a document from a position closer to the first image sensor.

Images