JP2005277774A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To read both a fixed original and a carried original with high image quality. <P>SOLUTION: In the case that the height of original faces between the original fixing reading and the original skimming-through reading differs by H1-H2=Δ1, a step difference is provided between a first rail part 73A and a second rail part 73B of rails 73 for guiding a shared read unit 74 for reading the image of the original, and the height H3 of the first rail part 73A and the height H4 of the second rail part 73B are differentiated by H3-H4=Δ2. Then a relation of Δ1=Δ2 is set by matching the step difference Δ2 of the rails 73 with the height difference Δ1 of the original faces described as above, that is, by deviating the height of the second rail part 73B by the height of a jump base 44. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus or the like that reads an image on an original, and more particularly, to an image reading apparatus that can read a fixed original and a conveyed original using the same reading unit.

  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, the original is irradiated with light using a light source extending in the main scanning direction, and the reflected light reflected from the irradiated original is read by the reading unit.

  As a reading method in such a conventional image reading apparatus, a so-called platen scanning method (original fixed reading method) in which an original is placed on a platen glass and an image of the original is read while moving the reading unit while fixing the original. In addition, a so-called CVT (Constant Velocity Transport) method (document flow reading method) that reads an image of a document while moving the document while fixing a reading unit below the platen glass is known (see Patent Document 1). ). At present, an image reading apparatus that shares a reading unit and can read an image of a document by a platen scan method and a CVT method has been put into practical use.

Japanese Unexamined Patent Publication No. 2001-223832 (page 4-5, FIG. 1)

  By the way, in the conventional image reading apparatus, as the above-described reading unit, reflected light from a document irradiated by a light source such as a xenon lamp is reflected through a plurality of mirrors, and is connected to a CCD sensor or the like by an imaging lens. A system using a reduction optical system for imaging is common. In the method using the reduction optical system, there is a problem that the apparatus becomes large because a plurality of mirrors must be provided. Therefore, recently, for example, a CIS (Contact Image Sensor) using a contact optical system that uses an LED (Light Emitting Diode) with a small shape as a light source and directly reads an image with a linear sensor via a Selfoc lens, for example. The use of an image sensor has been studied.

  However, when the above-described CIS is used, the depth of focus is significantly shallower than when the reduction optical system is used. If the distance between the CIS and the document surface is slightly deviated, the focus is shifted. The scanned image is blurred. For this reason, when the reading unit is shared and the CIS is adopted as the reading unit of the image reading apparatus that reads an image by the platen glass method and the CVT method, the height of the document surface placed on the platen glass, and the CVT When the height of the document surface conveyed by is different, either one of the images may be blurred.

In addition, when reading an image of a document using the CVT method, a reading unit is fixed to the lower side of the platen glass. If foreign matter adheres to the platen glass, sub-scanning is performed in the read image data. Directional black streaks occur, leading to degradation of the quality of the read image. Therefore, in Patent Document 1 described above, a technique is provided in which a jump table is disposed upstream of the platen glass in the document conveyance direction so that the document conveyance position is separated from the platen glass surface and the document is conveyed in a state of being floated from the platen glass. Is described.
Then, when such a CIS is used, if such a jump stand is arranged, a difference is more likely to occur between the height of the document surface placed on the platen glass and the height of the document surface conveyed by the CVT. Therefore, the blur of the image becomes remarkable.

The present invention has been made to solve such a technical problem, and an object of the present invention is to read both a fixed original and a conveyed original with high image quality.
Another object is to suppress blurring of a read image when the reading height of a fixed original and the reading height of a conveyed original are different.

  For this purpose, the image reading apparatus to which the present invention is applied includes a placing means for placing a document, a transporting means for transporting the document, and an image of the document placed on the placing means as a first. A reading unit including a light receiving element that reads an image of a document that is read at a reading position and is conveyed by a conveying unit at a second reading position; and an optical path length from the reading surface of the document to the light receiving element at the first reading position; Adjusting means for adjusting the optical path length from the reading surface of the document to the light receiving element at the second reading position.

  Here, the heights of the first reading position and the second reading position are different, and the adjusting means adjusts the height of the light receiving element according to the heights of the first reading position and the second reading position. It can be characterized by different. The reading unit includes a light source that emits light toward the document, a lens that collects reflected light from the document, and a sensor that receives the reflected light collected by the lens. The light source is constituted by an LED array in which a plurality of LEDs (Light Emitting Diodes) are arranged, and the lens is constituted by a Selfoc lens array in which a plurality of Selfoc lenses are arranged. Can do. Further, the adjusting means may include a rail that guides the reading means while changing the height of the reading means between the first reading position and the second reading position.

  From another point of view, an image reading apparatus to which the present invention is applied includes a placement unit that places a document, a transport unit that transports the document, and an image of the document placed on the placement unit. A reading unit that reads an image of a document conveyed by the reading and conveying unit; and a guide unit that guides the document conveyed by the conveying unit so that the document is placed at substantially the same height as the document placed on the placing unit. It is out.

  Here, the placing means has a transmission member for placing the document, and the guide means has a guide member formed at substantially the same height as the upper surface of the transmission member. The member may be provided on the upstream side in the document conveying direction from the reading position of the document conveyed by the conveying unit and read by the reading unit. Further, the reading means can be characterized by comprising a CIS (Contact Image Sensor).

  Further, from another viewpoint, the image reading apparatus to which the present invention is applied is a first member that reads a transmission member on which a document is placed and a document image placed on a document placement portion of the transmission member. And a reading unit that executes a second reading mode that reads an image of a document that is fixed to a lower part of the document passage unit of the transmission member and passes over the document passage unit. The thicknesses of the document placement portion and the document passage portion in the transmissive member so that the space conversion distance between the reading portion and the document and the space conversion distance between the reading portion and the document in the second reading mode are substantially the same. It is characterized by having different thickness or material.

  Here, the reading unit may include a contact image sensor. The transmission member further includes a step member that is formed with a predetermined step from the document passage portion of the transmission member and separates the conveyed document by a predetermined distance from the document passage portion, and the document passage portion is set to be thicker than the document placement portion. Can be characterized. Furthermore, the document placement portion and the document passage portion may be configured by different transmissive members.

  According to the present invention, both a fixed original and a conveyed original can be read with high image quality.

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 large and includes a document feeding device 10 as a conveying unit that sequentially conveys a document from a stacked document bundle, a scanner device 70 that reads an image by scanning, and a processing device that processes a read image signal. It is roughly divided into 80.

  A document feeder 10 as a conveying unit 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 conveyance path 31 where the original is first conveyed, a take-away roll 16 that conveys the originals that are being fed one by one to the downstream roll, and further conveys 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 conveyance path 31 as a conveyance path is provided with a baffle 41 that rotates around a fulcrum according to the loop state of the conveyed document. Further, a CIS (Contact Image Sensor) 50 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 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.

The scanner device 70 can include the document feeding device 10 described above, supports the document feeding device 10 with a device frame 71, and reads an image of a document conveyed by the document feeding device 10. The scanner device 70 is transported to a device frame 71 by a first platen glass 72A serving as a placement unit or a document placement portion for placing a document to be read in a stationary state, or a document feeder 10. A second platen glass 72B is provided as a document passage portion that forms an opening for light for reading the document. Here, the first platen glass 72A and the second platen glass 72B are constituted by, for example, transparent glass plates having a long plate-like structure. In the present embodiment, the first platen glass 72A and the second platen glass 72B as the transmission members are made of the same material and the same thickness.
In the present embodiment, the document feeder 10 is attached to the scanner device 70 so as to be swingable with the back side as a fulcrum, and when the document is set on the first platen glass 72A, the document is The document feeder 10 is lifted to place a document, and then the document feeder 10 is lowered to the scanning device 70 and pressed.

  In addition, the scanner device 70 is disposed in the device frame 71 along a substantially horizontal direction, is movably disposed on the rail 73, is stationary under the second platen glass 72B, and One platen glass 72A is provided with a common reading unit 74 as a reading means or reading unit for reading an image by scanning over the entire platen glass 72A. Here, the rail 73 is formed one step higher than the first rail portion 73A below the first rail portion 73A and the first rail portion 73A formed below the first platen glass 72A. A second rail portion 73B, and a skewed portion 73C that connects the first rail portion 73A and the second rail portion 73B.

  In the present embodiment, the common reading unit 74 is stopped below the second platen glass 72B, and at the same time of transporting a document for reading the first side of the document (simultaneous document transport, not the exact time coincidence). It is possible to read the second side of the document by the CIS 50 at the same time. That is, by using the common reading unit 74 and the CIS 50, it is possible to read the images on both the front and back sides of the document by one transport of the document to the transport path.

  FIG. 2 is a diagram for explaining the structure of the CIS 50 and the vicinity of the CIS 50. As shown in FIG. 2, the CIS 50 is provided between the platen roll 19 and the out roll 20. Further, in the present embodiment, a jump base 44 as a step member or a guide member is attached on the upper surface of the second platen glass 72B and slightly upstream of the platen roll 19. One side (first side) of the document passes through the jump table 44 and is urged toward the second platen glass 72B by the platen roll 19 while being separated from the second platen glass 72B by a predetermined distance. One image is read by the shared reading unit 74. This prevents a situation in which the conveyed document is rubbed against the second platen glass 72B and dirt is attached to the second platen glass 72B. 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 housing 50 a, a glass 51 mounted on the housing 50 a, an LED array 52 that transmits light through the glass 51 and irradiates the second surface of the document, and collects reflected light from the LED array 52. A self-focusing lens 53 that emits light and a line sensor 54 that reads the light collected by the self-focusing lens 53 are provided. 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.

  In addition, 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 that abuts the original pressed by the control member 55 are provided in the conveyance path constituting the reading unit. However, while the control member 55 is attached to the document feeder 10 (see FIG. 1) via the CIS 50, the abutting member 60 is attached to the scanner device 70 (see FIG. 1). Further, a guide member 61 is provided on the downstream side of the abutting member 60, and an opening 63 is formed between the guide member 61 and the abutting member 60. In a portion continuous with the opening 63, a dust storage portion 62 is provided as a collection portion for collecting dust and dirt adhering to the surface of the document. The control member 55 and the abutting member 60 are positioned in the conveyance path from the front surface to the rear surface of the document feeder 10 in a direction orthogonal to the document conveyance path (that is, from the front surface to the rear surface of the document feeder device 10). Correspondingly provided.

Here, the control member 55 is configured by a leaf spring made of a U-shaped sheet metal wound around a shaft 55a provided in the CIS 50, and is conveyed by making the control member 55 flexible. The thickness of the incoming document can be absorbed, and even a document with a bent trace can be stably conveyed.
Further, the front end side of the control member 55 extends to the vicinity of a reading position by the CIS 50, and a hemming bent portion 55b is provided at a portion that comes into contact with the original, and it comes into contact with the original and the smooth to generate paper dust or the like. Can be prevented. The distance between the folding portion 55b of the control member 55 and the abutting member 60 (gap for passing the document) is set to about 0.1 to 1.0 mm.

  On the other hand, the abutting member 60 is provided on the upstream side in the document conveyance direction, and a conveyance surface 60a for guiding the document to be conveyed, and one level lower than the conveyance surface 60a on the downstream side in the document conveyance direction from the conveyance surface 60a. And a step surface 60b formed. Further, the step surface 60b is formed so as to face the extension line of the light focus point by the SELFOC lens 53, and a white reference tape 64 made of a biaxially stretched polyester film is pasted on the step surface 60b. It is attached. Therefore, the white reference tape 64 is attached to the scanner device 70 via the abutting member 60. In the present embodiment, the upper surface of the white reference tape 64 is arranged in a state of being exposed to the conveyance path. On the other hand, on the lower side of the abutting member 60 and on the upper side of the first platen glass 72A, a white reference plate 65 is attached so as to be in close contact with the first platen glass 72A. The white reference tape 64 is used to acquire shading data in the CIS 50, and the white reference plate 65 is used to acquire shading data in the shared reading unit 74.

  Here, since the CIS 50 employs the SELFOC lens 53 as the optical imaging lens, the focal point (field of view) seismic intensity is as shallow as about ± 0.3 mm, which is approximately the same as when the scanner device 70 is used. The depth is 1/13 or less. When reading with the CIS 50, it is required to keep 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. 2 indicates the movement of the document when the control member 55 is provided. It is understood that the document to be conveyed is conveyed while being pressed against the abutting member 60. That is, the control member 55 reads the conveyed document while being pressed against the abutting member 60, thereby improving the sweetness of the focus when the CIS 50 having a shallow depth of field is used.

  FIG. 3 is a diagram for explaining the structure of the shared reading unit 74. In the present embodiment, this shared reading unit is also configured by CIS. As shown in FIG. 3, the shared reading unit 74 includes a housing 74a, a glass 75 attached to the housing 74a, and an LED array as a light source that transmits the light to the first surface of the document through the glass 75. 76, a Selfoc lens array 77 as a lens for condensing the reflected light from the LED array 76, a line sensor 78 as a light receiving element or sensor for reading the light collected by the Selfoc lens array 77, and a rail 73, and a caster 79 for sliding on 73. As the line sensor 78, a CCD, a CMOS sensor, a contact type sensor, or the like can be used similarly to the line sensor 54 in the CIS 50 described above, and an image with an actual width (for example, A4 longitudinal width 297 mm) can be read. . In the shared reading unit 74, 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, and the housing can be Miniaturization and power consumption can be reduced.

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 the present embodiment is applied is large and controls the signal processing unit 81 that processes image information obtained from the sensors (the common reading unit 74 and the CIS 50), the document feeding device 10, and the scanner device 70. And a control unit 90. The signal processing unit 81 performs predetermined image processing on each output from the line sensor 78 of the shared reading unit 74 that reads the front surface (first surface) of the document and the line sensor 54 of the CIS 50 that reads the back surface (second surface). Has been given. The signal processing unit 81 includes an AFE (Analog Front End) 82 that processes an analog signal with respect to an output from the line sensor 54, and an ADC (Analog to Digital Converter) 83 that converts the analog signal into a digital signal. Yes. However, these functions may be configured to be processed inside the CIS 50. The signal processing unit 81 is provided with two systems of image processing circuits for performing various processing such as shading correction and offset correction on the digital signal, and the surface (first surface) read by the shared reading unit 74. A first image processing circuit 100 that performs image processing on the image data of the second image, and a second image processing circuit 200 that performs image processing on the image data on the back surface (second surface) read by the CIS 50. Outputs from these image processing circuits are output to a host system such as an IOT (Image Output Terminal) such as a printer or a personal computer (PC).

  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 a control for various types of double-sided reading and a single-sided reading, a CIS / that controls the common reading unit 74 and the CIS 50. The CIS control 92, the lamp control 93 for controlling the LED array 52 of the CIS 50 and the LED array 76 of the shared reading unit 74 in accordance with the reading timing, and the motor in the scanner device 70 are turned on and off to move the shared reading unit 74. A scan control 94 for controlling, a motor control in the document feeder 10, a transport mechanism control 95 for controlling various roll operations, feed clutch operations, gate switching operations, and the like are provided. 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. As such a reading mode, a double-sided simultaneous reading mode using one pass (no reversal), a reversing double-sided reading mode using a reversing pass, a document flow reading mode that is single-sided reading using one pass, or the first platen glass 72A. A document fixed reading mode is conceivable in which a document is placed on and read.

  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 the original is fixedly read or whether the original is flown and read (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 or sensors (not shown) provided below the first platen glass 72A. 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 original is fixed, reading is performed on one side by fixing the original (the original is placed and fixed on the first platen glass 72A) (step 102). In this one-side reading by fixing the original, the line sensor 78 reads the common reading unit 74 while moving the lower side of the first platen glass 72A while the original is placed and fixed on the first platen glass 72A. Made.

  On the other hand, if it is determined in step 101 that the document flow is read, it is next determined whether or not the conveyed document, that is, the document placed on the document tray 11 is a single-sided document (step 103). 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 103 that the original is a single-sided original, single-sided reading is performed by one pass (one-time original conveyance pass without using a reverse pass) (step 104). In this one-pass single-sided reading, either the reading by the line 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 line sensor 78 should be selected. Is preferred. 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.

  Here, if it is not a single-sided original in step 103, that is, if it is a double-sided original, it is determined whether or not the original is a white / black original (step 105). The determination in step 105 is determined by the selection from the user or the automatic selection reading function as in step 103. 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 next determined whether or not the image quality is important (step 106). 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 step 106 that the image quality is important, double-sided reading is executed by the reverse pass (step 107). That is, the line sensor 78 reads both the first side of the document and the second side of the document without reading by the CIS 50. 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 105 or when a color image output is required in step 106, for example, when subtle hues such as business colors are not emphasized, plus one color In the case of (including other one color such as red or blue in addition to black), if the image quality is not very important and other factors such as productivity are important, the reverse path is not used. Simultaneous reading on both sides by one pass is performed (step 108). In other words, the first surface is read by the line sensor 78, and the reading of the second surface by the CIS 50 is performed in the same conveyance path during the reading conveyance 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.

In the single-sided scanning by one pass in step 104, the double-sided scanning by reversing pass in step 107, and the simultaneous double-sided scanning by one pass in step 108, the shared reading is performed while the original is transported and passed over the second platen glass 72B. Reading by the line sensor 78 is performed while fixing the unit 74 to the lower side of the second platen glass 72B.
Further, the processing flow shown in FIG. 5 is simplified, and when reading a black and white original in double-sided original reading, double-sided simultaneous reading in step 108 is executed, and in the case of a color original, the reverse path in step 107 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.

FIG. 6 is a diagram for explaining original fixed reading as the first reading mode and original flow reading as the second reading mode using the shared reading unit 74 in the present embodiment.
In the present embodiment, the material and thickness of the first platen glass 72A used for document fixed reading and the second platen glass 72B used for document flow reading are the same, and these first platen glass 72A. The height of the upper surface and the height of the upper surface of the second platen glass 72B are set to the first height H1. In the fixed document reading, since the document is placed on the first platen glass 72A, the height of the document surface in the fixed document reading becomes the first height H1. On the other hand, in the document flow reading, the document is jumped by the jump table 44 attached to the second platen glass 72B and conveyed while being lifted from the second platen glass 72B. The height is the second height H2. In other words, the height of the original surface is different by H1-H2 = Δ1 between the original fixed reading and the original flow reading.

  On the other hand, in the present embodiment, a step is provided between the first rail portion 73A and the second rail portion 73B of the rail 73 so that the height H3 of the first rail portion 73A and the second rail portion are The height H4 of 73B is changed by H3-H4 = Δ2. Then, by shifting the height of the second rail portion 73B by the height of the jump base 44 so that the level difference Δ2 of the rail 73 coincides with the above-described difference Δ1 in the height of the original surface, Δ1 = Δ2 is set. In other words, the scanning control 94 and the rail 73 constituting the adjusting means or the moving unit allow the common reading at the first reading position below the first platen glass 72A and the second reading position below the second platen glass 72B. The height of the unit 74 is changed. Thereby, the optical path length between the original surface and the line sensor 78 in the original fixed reading and the optical path length between the original surface and the line sensor 78 in the original flow reading can be made the same. By performing such settings, in this embodiment, it becomes possible to adjust the depth of focus in both the fixed document reading and the document flow reading, and the fixed document reading and the document flow reading are performed using the CIS having a shallow focal depth. In both cases, a beautiful read image without blur can be obtained.

  In this embodiment, the LED array 76 is used as the light source of the shared reading unit 74. However, since the LED array 76 includes a plurality of LEDs that are point light sources arranged at a predetermined interval, the LED array 76 is used. The illuminance distribution changes according to the distance from the. For this reason, if the distance between the LED array 76 and the original surface in the original fixed reading and the distance between the LED array 76 and the original surface in the original flow reading are different, stripe-like image unevenness is present in one of the read images. There is a risk of appearing. In the present embodiment, by adopting the above-described configuration, the distance between the LED array 76 and the original surface can be made constant in original fixed reading and original flow reading. it can.

In the present embodiment, the shared reading unit 74 is movably arranged on the rail 73 having a step, but the height of the shared reading unit 74 in the fixed document reading and the shared reading unit 74 in the document flow reading. Any other method may be used as long as it can be shifted by a difference Δ1 in height of the original surface.
Further, in the present embodiment, the mode in which the first platen glass 72A and the second platen glass 72B are provided separately has been described. However, the present invention is not limited to this, and both are integrally configured. The platen glass that has been used may be used.

-Embodiment 2-
The present embodiment is substantially the same as the first embodiment, except that the height of the document surface in the fixed document reading and the height of the document surface in the document flow reading are matched. In addition, in this Embodiment, about the thing similar to Embodiment 1, the same code | symbol as Embodiment 1 is attached | subjected and the detailed description is abbreviate | omitted.

  FIG. 7 is a diagram showing an image reading apparatus to which the present embodiment is applied. This image reading apparatus is substantially the same as that described in the first embodiment. However, the rail 73 to which the shared reading unit 74 is movably attached is not provided with a skew portion, and is linear. This is different from the first embodiment. The shared reading unit 74 is the same as that described in the first embodiment shown in FIG.

FIG. 8 is a diagram for explaining original fixed reading and original flow reading using the common reading unit 74 in the present embodiment.
In the present embodiment, the material and thickness of the first platen glass 72A used for original fixed reading and the second platen glass 72B used for original flow reading are the same, but the first platen glass 72A. The upper surface of the second platen glass 72B is attached to the upper surface of the second lower glass plate 72B. The difference between the height H11 of the upper surface of the first platen glass 72A and the height H12 of the upper surface of the second platen glass 72B is different by H11−H12 = Δ11. The thickness d of the jump table 44 mounted on the upper surface of the second platen glass 72B is set so that the height of the upper surface of the jump plate 44 matches the height of the upper surface of the first platen glass 72A. It is selected so that d = Δ11.

  Thereby, also in the present embodiment, the optical path length between the original surface and the line sensor 78 in the original fixed reading and the optical path length between the original surface and the line sensor 78 in the original flow reading are made the same. Can do. By performing such settings, in this embodiment, it becomes possible to adjust the depth of focus in both the fixed document reading and the document flow reading, and the fixed document reading and the document flow reading are performed using the CIS having a shallow focal depth. In both cases, a beautiful read image without blur can be obtained. In particular, in the present embodiment, the rail 73 is provided in a straight line and the shared reading unit 74 only needs to be moved in the horizontal direction, so that the drive control by the scan control 94 is facilitated.

-Third embodiment-
Although the present embodiment is substantially the same as the second embodiment, the substantial optical path length (spatial conversion distance) can be reduced by changing the thicknesses of the first platen glass 72A and the second platen glass 72B. The difference is that they match. In the present embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 9 is a diagram for explaining document fixed reading and document flow reading using the shared reading unit 74 in the present embodiment.
In the present embodiment, the material of the first platen glass 72A used for original fixed reading and the second platen glass 72B used for original flow reading are the same, but the second platen glass 72B is more suitable. It is thick. However, the height of the upper surface of the first platen glass 72A and the upper surface of the second platen glass 72B are set to the same height H21. On the other hand, in the document flow reading, the document is jumped by the jump table 44 attached to the second platen glass 72B and conveyed while being lifted from the second platen glass 72B. The height is the second height H22. That is, the height of the original surface is different by H21−H22 = Δ21 between original fixed reading and original flow reading.

  Here, in this embodiment, the second platen glass 72B is made thicker than the first platen glass 72A, so that the spatial conversion distance of reflected light from the original to be read is set from the original that is fixedly read. It is longer than the space equivalent distance of the reflected light. The difference in thickness between the first platen glass 72A and the second platen glass 72B is made to correspond to the thickness d of the jump table 44. The difference in thickness between the first platen glass 72A and the second platen glass 72B does not necessarily match the thickness d of the jump table 44. In order to change the space conversion distance, the first platen glass 72A and the second platen glass 72A having different refractive indexes are used in addition to the method of changing the thicknesses of the first platen glass 72A and the second platen glass 72B. There is also a technique using the platen glass 72B.

  Thus, in the present embodiment, the substantial optical path length (space conversion distance) between the document surface and the line sensor 78 in the fixed document reading, and the substantial between the document surface and the line sensor 78 in the document flow reading. The optical path length (space conversion distance) can be made the same. By performing such settings, in this embodiment, it becomes possible to adjust the depth of focus in both the fixed document reading and the document flow reading, and the fixed document reading and the document flow reading are performed using the CIS having a shallow focal depth. In both cases, a beautiful read image without blur can be obtained. In particular, in the present embodiment, the rail 73 is provided in a straight line and the shared reading unit 74 only needs to be moved in the horizontal direction, so that the drive control by the scan control 94 is facilitated. Further, since the upper surface of the first platen glass 72A and the upper surface of the second platen glass 72B may be set to the same height H21, positioning is facilitated.

1 is an explanatory diagram illustrating an image reading apparatus according to Embodiment 1. FIG. It is a figure for demonstrating the structure of CIS and the CIS vicinity. It is a figure for demonstrating the structure of a shared reading unit. It is a figure for demonstrating a processing apparatus. It is the flowchart which showed an example of the process performed by image reading control. FIG. 6 is a diagram for explaining document fixed reading and document flow reading using a shared reading unit in the first embodiment. 5 is an explanatory diagram showing an image reading device according to Embodiments 2 and 3. FIG. FIG. 10 is a diagram for explaining document fixed reading and document flow reading using a shared reading unit in the second embodiment. FIG. 10 is a diagram for explaining document fixed reading and document flow reading using a shared reading unit in the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Document feeder, 11 ... Document tray, 18 ... Registration roll, 19 ... Platen roll, 20 ... Out roll, 40 ... Ejection tray, 44 ... Jump stand, 50 ... CIS, 50a ... Housing, 51 ... Glass, 52 ... LED Array, 53 ... Selfoc lens, 54 ... Line sensor, 55 ... Control member, 60 ... Abutting member, 64 ... White reference tape, 65 ... White reference plate, 70 ... Scanner device, 71 ... Device frame, 72A ... First Platen glass, 72B ... second platen glass, 73 ... rail, 73A ... first rail part, 73B ... second rail part, 73C ... skew part, 74 ... shared reading unit, 74a ... housing, 75 ... Glass, 76 ... LED array, 77 ... Selfoc lens array, 78 ... Line sensor, 79 ... Caster, 80 ... Processing device, 0 ... control unit

Claims (13)

A placing means for placing a document;
Conveying means for conveying an original;
A reading unit including a light receiving element that reads an image of a document placed on the placing unit at a first reading position and reads an image of the document conveyed by the conveying unit at a second reading position;
Image reading including an optical path length from the reading surface of the original document to the light receiving element at the first reading position and an adjustment unit that matches an optical path length from the reading surface of the original document to the light receiving element at the second reading position. apparatus. The first reading position and the second reading position are different in height,
The image reading apparatus according to claim 1, wherein the adjusting unit varies the height of the light receiving element in accordance with a height of the first reading position and the second reading position. The reading means includes
A light source that emits light toward the document;
A lens that collects the reflected light from the document;
The image reading apparatus according to claim 1, further comprising a sensor that receives the reflected light collected by the lens.   The light source is configured by an LED array in which a plurality of LEDs (Light Emitting Diodes) are arranged, and the lens is configured by a Selfoc lens array in which a plurality of Selfoc lenses are arranged. 3. The image reading apparatus according to 3.   2. The image according to claim 1, wherein the adjustment unit includes a rail that guides the reading unit while varying a height of the reading unit between the first reading position and the second reading position. Reader. A placing means for placing a document;
Conveying means for conveying an original;
Reading means for reading an image of a document placed on the placing means, and reading an image of a document conveyed by the conveying means;
An image reading apparatus comprising: a guide unit that guides a document transported by the transport unit so that the document is at substantially the same height as the document placed on the placing unit.   7. The apparatus according to claim 6, wherein the placing means has a transmitting member for placing a document, and the guiding means has a guiding member formed at substantially the same height as the upper surface of the transmitting member. Image reading device.   The image reading apparatus according to claim 7, wherein the guide member is provided on an upstream side in a document conveying direction from a reading position of a document conveyed by the conveying unit and read by the reading unit.   The image reading apparatus according to claim 6, wherein the reading unit includes a CIS (Contact Image Sensor). A transparent member on which the document is placed;
A first reading mode for reading an image of a document placed on the document placing portion of the transmissive member, and an image of the document that is fixed to the lower portion of the document passage portion of the transmissive member and passes over the document passage portion. And a second reading mode for reading
The transmission member so that the space conversion distance between the reading unit and the document in the first reading mode and the space conversion distance between the reading unit and the document in the second reading mode are substantially the same. An image reading apparatus characterized in that the document placement portion and the document passage portion of the document have different thicknesses or materials.   The image reading apparatus according to claim 10, wherein the reading unit includes a contact image sensor. A step member that is formed with a predetermined step from the document passage portion in the transmission member, and that separates the conveyed document by a predetermined distance from the document passage portion;
The image reading apparatus according to claim 10, wherein the document passage portion is set thicker than the document placement portion.   The image reading apparatus according to claim 10, wherein the document placement unit and the document passage unit are configured by different transmissive members.

Images