JP3812499B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that is compact and low-cost and capable of reading images on both sides of a document at high speed.
[0002]
[Prior art]
Some scanners, facsimiles, copiers, and the like are equipped with an image reading device that automatically and sequentially feeds a bundle of sheet-like documents such as paper and reads an image of each document. In general, the image reading apparatus includes a sheet fixing type that temporarily fixes and reads sequentially supplied documents, and a sheet through type that reads a document conveyed without fixing the document.
[0003]
The sheet fixing type image reading apparatus supplies, for example, the uppermost or lowermost original from a bundle of originals placed on a paper feed tray onto a platen glass such as a flatbed scanner by a pickup roller and a conveyor belt. Once the original is stopped on the platen glass, the scanner below the platen glass is moved to read the image information of the original, and the original after reading is discharged to the paper discharge tray, and the original to be read next is read. Similarly, the image of each original is automatically and sequentially read by supplying image data from the paper feed tray onto the platen glass and repeating the reading of the image information by the scanner.
[0004]
On the other hand, in the sheet-through type image reading apparatus, the scanner is stopped in advance under the platen glass, and sequentially conveyed onto the platen glass from the bundle of documents placed on the paper feed tray by the pick-up roller and the conveyance roller. The original to be read is read by the scanner.
[0005]
The sheet fixing type image reading apparatus temporarily stops the conveyed document at a predetermined position on the platen glass and then moves the scanner to read the document. There is a drawback in that the processing time is long compared to the sheet-through type image reading apparatus that reads a time lag and a time for returning the scanner to the initial position without stopping the document. This drawback becomes more conspicuous when reading both sides of a document automatically.
[0006]
Therefore, an image reading apparatus capable of reading both sides of a document often adopts a sheet-through type, and a conventional sheet-through type image reading apparatus is disclosed in, for example, JP-A-7-175279. There is.
[0007]
18 to 20 are schematic diagrams for explaining the outline of a conventional sheet-through type image reading apparatus 800. As shown in FIG. 18, the image reading apparatus 800 has a bundle of documents to be read. A paper feed tray 80, a pickup roller 81a for picking up the uppermost document from the paper feed tray, a paper feed roller 81b for feeding the document to the transport path 82, and a document placed on the transport path 82 as appropriate. A transport roller 81c for transport, a platen glass 83 disposed below the transport path, a scanner 84 of a reduction optical system composed of a CCD or the like for reading a document through the platen glass 83, and a reverse feed and discharge of the document. And a paper discharge roller 81d.
[0008]
The conveyance path 82 allows the original supplied from the paper feed tray 80 to pass over the platen glass 83 while being inverted downward, and is further discharged from below the paper feed tray 80 to a paper discharge tray (not shown). It is curved in a substantially U shape so as to be guided, and further, a return path 85 is provided in the transport path 82, which leads from the downstream side to the upstream side of the platen glass 83.
[0009]
Further, a document set sensor 86a, a lead sensor 86b, and a reversing sensor 86c that detect the presence or absence of a document and output a detection signal are arranged at required positions on the conveyance path 82, and are based on the detection signals of the sensors. Thus, the operation of a motor or clutch that rotates the pickup roller 81a, the paper feed roller 81b, the transport roller 81c, or the paper discharge roller 81d, or the reading operation of the scanner 84 is controlled.
[0010]
As shown in FIG. 18, the bundle of documents placed on the paper feed tray 80 has a top surface as a front surface. After the front surface is first read, the back surface of the same document is read, and the next document The front and back are sequentially read. In each figure, the first side, the second side,... Are shown in the document according to the reading order.
[0011]
From the bundle of documents placed on the paper feed tray 80, the uppermost document is taken out by the pickup roller 81 a and supplied to the conveyance path 82 by the paper feed roller 81. The document is conveyed by the conveyance roller 81c so as to be reversed in the conveyance path 82, and when passing over the platen glass 83, the scanner 84 reads the image of the document surface, that is, the first surface. The document whose first surface has been read is further transported, and the discharge roller 81d stops with the rear side in the transport direction of the document held between the nip surfaces of the discharge roller 81d, as shown in FIG. .
[0012]
The sheet discharge roller 81d rotates in the reverse direction while the document is held, and the document whose first surface is read is conveyed to the return path 85 as shown in FIG. The original returns from the return path 85 to the conveyance path 82 on the upstream side of the platen glass 83. Similarly, the original is conveyed so as to be reversed downward in the conveyance path 82 and passes over the platen glass 83. Thus, the image on the second surface is read.
[0013]
The document whose first surface and second surface are read is further conveyed, and as shown in FIG. 20 (a), the discharge roller with the rear side in the conveyance direction of the document held between the nip surfaces of the discharge roller 81d. 81d stops. At this stage, scanning of both sides of the document has been completed. However, when the document is discharged to the discharge tray as it is, the first surface becomes the upper surface, and the read documents are sequentially stacked on the upper surface side. The page order placed on the tray 80 is not aligned. Accordingly, the paper discharge roller 81d is reversed again to send the original to the return path 85, and similarly, the conveying path 82 is conveyed so as to be reversed downward, and as shown in FIG. The sheet is discharged to the sheet discharge tray so that the surface becomes the lower surface. In this way, it is possible to sequentially take out originals from a bundle of originals and read images on both sides of the originals.
[0014]
[Problems to be solved by the invention]
However, in the image reading apparatus 800, it is necessary to invert the original in order to read the second side of the original and further invert the original in order to align the pages of the read original, and the control mechanism is complicated. Since the transport distance is also long, there is a drawback that the document is likely to be skewed during the transport and easily jammed. In addition, since the next document to be read cannot be supplied to the conveyance path 82 until the second reversal of the document is completed, there is a disadvantage that a reading time several times as long as the normal single-sided reading is required.
[0015]
On the other hand, a reading unit that reads the front surface of the document and a reading unit that reads the back side of the document are arranged at substantially opposite positions on the document transport path, and the images read simultaneously on the front and back surfaces of the document transported on the transport path in one transport. A reading device has also been proposed (Japanese Patent Laid-Open No. 1-194658). However, in order to simultaneously read the first side and the second side of the document, an image memory for temporarily storing the read image data and an image processing circuit for performing shading processing of the image data are provided for each reading unit. There is a problem that the cost of the image reading apparatus becomes high.
[0016]
The present invention has been made in view of these problems, and provides an image reading apparatus capable of reading both sides of an original, shortening the reading time of the original, and simple and low-cost. The purpose is to provide.
[0017]
Another object of the present invention is to provide an image reading apparatus capable of sharing an image processing circuit for processing each image data read on both sides with each scanner.
[0018]
[Means for Solving the Problems]
  An image reading apparatus according to the present invention includes a transport unit that transports a document placed on a paper feed tray to a discharge tray side through a transport path, and a first surface of the document that is disposed and transported on the transport path. A first reading unit that reads the image of the image, and a branch from the conveyance path on a downstream side of the first reading unit.To communicate with the output trayA switchback conveyance path provided; a second reading unit configured to read an image on a second surface of the document that is arranged and conveyed in the switchback conveyance path; After transporting to the downstream side of the bifurcation point, the original is reversely fed and sent to the switchback transport pathThen, the document whose second side is read is discharged from the switchback conveyance path to the discharge tray.As described above, the apparatus includes a control unit that controls the transport unit.
[0019]
  As a result, the original on which both the first surface and the second surface are read is sent to the switchback conveyance path after the first surface is completely read by the first reading means, and the second reading means causes the second reading means to read the original. Two sides are read. Therefore, the image reading of the first reading unit and the image reading of the second reading unit do not overlap. Further, the reversely fed document does not reach the reading position of the first reading unit, and after the first surface of the document is read, the document to be read next can be supplied to the conveyance path.Further, it is possible to read the first side and the second side of the document without overlapping with one switchback conveyance.
[0022]
  The present invention also provides:A transport unit that transports the document placed on the paper feed tray to the discharge tray side through the transport path; and a first reading unit that reads an image on the first surface of the document that is disposed on the transport path and is transported. A switchback conveyance path provided on the downstream side of the first reading means so as to diverge from the conveyance path and communicate with the paper discharge tray, and a second of the document conveyed while being disposed in the switchback conveyance path. A second reading means for reading an image on the surface, and when performing both-side reading of a document, after the document is transported to the downstream side of the branch point of the transport path, the document is reversely fed and sent to the switchback transport path; The original on which the second side is read is discharged from the switchback conveyance path to the paper discharge tray, or is discharged through the conveyance path after the second side of the original is read by the second reading means. To eject to the tray Is obtained and a control means for selectively controlling the said conveying means.
[0023]
In the present invention, the paper feed tray and the paper discharge tray are arranged vertically at a predetermined interval, and the switchback transport path is formed in a space between the paper feed tray and the paper discharge tray. Is.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image reading apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of the image reading apparatus 100, and FIG. 2 is a block diagram showing the control of the image reading apparatus 100.
[0025]
As shown in the drawing, the image reading apparatus 100 includes a paper feed tray 101 on which a bundle of documents to be read is placed, a pickup roller 102a that takes out and supplies the top sheet from the bundle of documents, a separation roller 102b, A retard roller 102 c, a conveyance path 104 that guides the supplied document to the paper discharge tray 103 while being reversed downward, a conveyance roller 105 that is appropriately disposed in the conveyance path 104 and conveys the document, and the most downstream of the conveyance path 104 A discharge roller 106 disposed on the side for discharging the original, a first reading unit (first reading unit) 107 disposed at a predetermined position on the conveyance path 104, and a conveyance path 104 downstream of the first reading unit 107. A switchback conveyance path 108 provided to diverge, and a second reading unit (second reading unit) arranged in the switchback conveyance path 108 Those formed by and a stage) 109. Further, a document set sensor 110 that detects the presence or absence of a document on the paper feed tray 101, a first read sensor (first detection means) 111 that detects a document at a predetermined position upstream of the first reading unit 107, and a switch A branch sensor 112 that detects a document on a transport path 104 immediately downstream of a branch point with the back transport path 108, and a second read sensor (second detection means) that detects a document at a predetermined position upstream of the second reading unit 109. 113).
[0026]
FIG. 2 is a block diagram showing the control of the image reading apparatus 100. The image reading control unit (control means) includes the document set sensor 110, the first read sensor 111, the branch sensor 112, and the second read sensor. Based on each detection signal 113, the first reading unit (scanner) 107, the second reading unit (scanner) 109, the motor, the paper feed clutch, and the like are controlled. Further, the image reading apparatus 100 is mounted on a main body having a function of a well-known and arbitrary facsimile machine and copying machine, and the configuration of the main body will not be described in detail. The image data read by the 107 and the second reading unit 109 is output to the main body control unit and transmitted by the printer via printing or CODEC. The figure shows a configuration in which an image reading control unit is provided in addition to the main body control unit, but a configuration in which the main body control unit controls the first reading unit 107 and the second reading unit 109, a motor, a paper feed clutch, and the like. It is also possible.
[0027]
The paper feed tray 101 is provided at an upper portion of the image reading apparatus 100 so as to be inclined in a direction in which a document is supplied, and a bundle of documents is placed so as to be aligned with the inclined lower end side of the paper feed tray 101. The A pickup roller 102a, a separation roller 102b, and a retard roller 102c are arranged in the vicinity of the inclined lower end side of the paper feed tray 101, and these, the conveyance roller 105, and the discharge roller 106 constitute a document conveyance unit. Yes.
[0028]
The pickup roller 102 a is for taking out the uppermost paper of the document placed on the paper feed tray 101, is pivotally supported by the swing arm 20, and can be brought into contact with and separated from the bottom surface of the paper feed tray 101. . The swing arm 20 swings up and down by a paper feed clutch (not shown), and the pickup roller 102a is separated from the paper feed tray 101 in a normal state such as when a document is placed. It is lowered so as to come into contact with the uppermost sheet of the document placed when the document is supplied. Since the pickup roller 102a can be lowered until it comes into contact with the bottom surface of the paper feed tray 101, the pickup roller 102a can always come into contact with the uppermost paper even if the thickness of the bundle of documents changes depending on the number of documents.
[0029]
On the other hand, the separation roller 102b and the retard roller 102c are arranged so that the surfaces of the respective rollers nip, and the separation roller 102b sends the document taken out by the pickup roller 102a to the conveyance path 104 at a constant speed. The retard roller 102c rotates in the direction opposite to the conveyance direction to reliably separate the uppermost sheet from the bundle of documents.
[0030]
The pickup roller 102a, the separation roller 102b, and the retard roller 102c are rotated by an unillustrated paper feed motor through appropriate gears, and the presence or absence of the document on the paper feed tray 101 is determined by the document setting. Based on the detection signal, the image reading control unit controls the operations of the pickup roller 102a, the separation roller 102b, and the retard roller 102c.
[0031]
The conveyance path 104 is a substantially U-shaped conveyance path that allows the paper feed tray 101 and the document discharge tray 103 to communicate with each other, and the document supplied from the paper feed tray 101 is inverted downward by the conveyance path 104. Are guided onto the first reading unit 107. That is, the upper surface of the paper feed tray 101 is the lower surface, and this surface is read by the first reading unit 107.
[0032]
In the conveyance path 104, a conveyance roller 105 for conveying the document is appropriately disposed. The conveying roller 105 is provided with a pair of a driving roller rotated by a motor and a driven roller driven by the rotation of the roller at an opposing position so as to sandwich the conveying path 104. A discharge roller 106 is provided on the most downstream side of the conveyance path 104. Similarly, the discharge roller 106 is provided with a pair of a drive roller and a driven roller so as to sandwich the conveyance path 104. In the discharge roller 106, a drive roller may be disposed below the conveyance path 104. preferable. As a result, it is possible to fly the document to be discharged far away, and the rotation direction of each discharge roller 106 arranged in the switchback conveyance path 108 to be described later matches, so that these are driven and controlled by one motor. It becomes possible. In FIG. 1, five transport rollers 105 and one discharge roller 106 are arranged in the transport path 104, but depending on the shape and distance of the transport path 104, the transport roller 105 and the discharge roller 106. Can be increased or decreased as appropriate.
[0033]
The first reading unit 107 includes a transparent platen glass 70 provided so as to be close to the conveyance path 104, a light source 71 that irradiates light on a document conveyed on the conveyance path 104 through the platen glass 70, and a document A reflection mirror 72 for guiding reflected light from the light in a predetermined direction, a lens 73 for converging the reflected light, and a charge coupled device 74 (hereinafter referred to as “CCD”) for converting the converged light into an electric signal. ), And is a movable image reading means disposed so as to be movable in the horizontal direction below the conveyance path 104, as shown in the figure.
[0034]
That is, the first reading unit 107 is used in combination with a reading unit of a flat bed scanner. When reading a document with the flat bed, the first reading unit 107 moves in the horizontal direction below the flat bed portion to read the document. Is read below the platen glass 70. In this manner, the images of the original document that is conveyed on the conveyance path 104 and passes immediately above the platen glass 70 are sequentially read.
[0035]
A first read sensor 111 is disposed at a predetermined position upstream of the first reading unit 107, detects a document conveyed on the conveyance path 104, and an image reading control unit detects the document on the basis of the detection signal. The document reading operation of the first reading unit 107 is controlled. That is, the first reading unit 107 starts reading an image after a predetermined count after the first read sensor 111 detects the presence of a document, and the first reading unit after a predetermined count after the first read sensor 111 detects the absence of the document. 107 finishes image reading.
[0036]
As shown in the drawing, the switchback conveyance path 108 is branched from the conveyance path 104 downstream of the first reading unit 107 and curved upward to reach the upper side of the paper discharge tray 103. In the switchback conveyance path 108, the discharge roller 106 is arranged similarly to the conveyance path 104, and further, a second reading unit 109 that reads the second surface of the document conveyed on the switchback conveyance path 108 is arranged. .
[0037]
FIG. 3 is an enlarged view of the vicinity of the branch point of the switchback conveyance path 108. As shown in FIG. A member 90 is provided. The guide member 90 is a thin piece that is wide in the width direction of the transport path 104, and is fixed so as to protrude obliquely downward from the upper side of the branch point of the transport path 104 toward the downstream side of the transport path 104. In the state, the tip is in contact with the bottom surface of the conveyance path 104.
[0038]
The guide member 90 arranged in this way is difficult to deform from the normal state to the upstream side because its tip abuts against the bottom surface of the conveyance path 104, but easily deforms to the downstream side. It is. Therefore, the document conveyed from the upstream side to the downstream side (in the right direction in the drawing) passes through the branch point by elastically deforming the guide member 90 by contacting the guide member 90 at the branch point. On the other hand, the document transported from the most downstream side of the transport path 104 to the upstream (in the left direction in the figure) contacts the guide member 90, but the guide member 90 is not elastically deformed and the document is switched to the switchback transport path 108. To guide. Similarly, the document conveyed from the switchback conveyance path 108 to the conveyance path 104 is guided to the downstream side of the conveyance path 104 without the guide member 90 being elastically deformed.
[0039]
The guide member 90 is an example. For example, instead of the guide member 90, a guide plate capable of swinging around a branch point is provided, and the conveying path 104 side or the switchback conveying path 108 is driven by a driving means such as a solenoid. The document to be conveyed may be guided to the conveyance path 104 or the switchback conveyance path 108 by swinging to the side. By adopting the guide plate, it is possible to convey a soft or thin document that does not have sufficient strength to elastically deform the guide member 90.
[0040]
The second reading unit 109 is a so-called contact image sensor (hereinafter referred to as “CIS”). Although not shown in detail in the drawing, the second reading unit 109 converges reflected light from a document irradiated by a light source. It is a fixed reading means that converges and reads on the photoconductive element with a fiber. As shown in the drawing, the second reading unit 109 is arranged on the lower side of the switchback conveyance path 108, and a document conveyed on the switchback conveyance path 108 with a platen roller 91 disposed at the opposite position. Are read in a nipped state, whereby the image of the original on the surface opposite to the first reading unit 107 is sequentially read.
[0041]
Here, the CIS employed in the second reading unit 109 generally has a shallow subject depth of about several tenths of a millimeter, and as described above, reads the image while the document is nipped by the platen roller 91. When the second reading unit 109 is arranged at a position where the switchback conveyance path 108 is curved, the original is likely to flutter, and the image read by the second reading unit 109 may be distorted. Further, since the gap between the second reading unit 109 and the platen roller 91 is very narrow, jamming is likely to occur when the document is guided to the gap in a curved state. Therefore, in the second reading unit 109, the position where the switchback conveyance path 108 is linear, in particular, as shown in the figure, the switchback conveyance path 108 is horizontal for a certain distance, and the document is not curved. It is preferable to arrange at a position to be conveyed linearly.
[0042]
Further, a second read sensor 113 is disposed at a predetermined position upstream of the second reading unit 109, and the image reading is performed based on the detection signal of the second read sensor 113, as in the first reading unit 107. The control unit controls the document reading operation of the second reading unit 109. In the present embodiment, a compact CIS is adopted as the second reading unit 109, but a CCD image sensor can be adopted in the same manner as the first reading unit 107.
[0043]
Hereinafter, the operation of the image reading apparatus 100 will be described with reference to the drawings.
The operation of the image reading apparatus 100 is different between the high-speed reading mode (first control) and the page alignment mode (second control). FIGS. 4 and 5 are flowcharts showing the operations of the image reading apparatus 100. FIGS. 6 to 12 are schematic views showing the state of conveyance of the document in each operation.
[0044]
FIG. 13A is a schematic diagram for explaining a document placed on the paper feed tray 101 and a reading order. In the image reading apparatus 100, a document is sequentially placed from the topmost sheet of the placed document. The upper surface is read as the first surface by the first reading unit 107 while being taken out and placed on the paper feed tray 101, and the lower surface is read by the second reading unit 109. Accordingly, as shown in the figure, a bundle of n originals is read sequentially from the upper surface of the uppermost sheet as the first surface, the second surface,..., And the upper surface of the lowermost sheet is the first ( The 2n-1) plane and the lower plane are read as the (2n) plane by the first reading unit 107 or the second reading unit 109, respectively, and the image reading ends.
[0045]
Note that the reading order in the present embodiment is an example. For example, as shown in FIG. 13B, it is of course possible to sequentially read out and read from the bottom sheet, and the reading order in that case is also possible. The upper surface of the bottom paper is the first surface, the lower surface is the second surface, the upper surface of the uppermost paper is the second (2n-1) surface, and the lower surface is the second n surface, respectively. Reading is performed by the first reading unit 107 or the second reading unit 109.
[0046]
First, before reading an image, a high-speed reading mode or a page alignment mode is selected on the operation unit. Although not shown in the drawing, in the image reading apparatus 100, the high-speed reading mode and the page alignment mode are selected on the liquid crystal panel of the operation unit. The selection may be, for example, a setting in which the page alignment mode is normally set and the high-speed reading mode is set only when an instruction is given, or vice versa.
Hereinafter, the operation in the high-speed reading mode will be described with reference to FIGS. 4 and 6 to 10.
[0047]
When the start button of the operation unit is pressed, the image reading apparatus 100 starts reading an image of a document. The document set sensor 110 detects whether or not a document is placed on the paper feed tray 101 (S1). When the document set sensor 110 outputs a detection signal (ON) indicating that a document is placed, Based on the detection signal, the image reading control unit activates the paper feed clutch (S2), and the swing arm 20 is lowered and the pickup roller 102a is placed on the uppermost sheet of the paper feed tray 101 as shown in FIG. Abut.
[0048]
When the motor further rotates (S3), the pickup roller 102a, the separation roller 102b, the retard roller 102c, and the transport roller 105 rotate, and as shown in FIG. 6B, the pickup roller 102a feeds out the original and the retard. The roller 102c separates only one uppermost original, and the original is sent to the conveyance path 104 by the separate roller 102b. The conveyance roller 105 conveys the document along the conveyance path 104.
[0049]
As shown in FIG. 7A, the first read sensor 111 detects the leading edge of the conveyed document and outputs (turns on) a detection signal (S4), and the image reading control unit outputs the detection signal. After the reception, after an elapse of a predetermined time (after T1 conveyance, S5), the image of the first reading unit 107 is read as shown in FIG. 7B (S6). The predetermined time (T1 conveyance) is performed until the detected leading edge of the document reaches the reading position of the first reading unit 107 according to the conveyance distance and the conveyance speed from the first read sensor 111 to the first reading unit 107. For example, it is possible to control by the count number of the stepping motor that rotates the conveyance roller 105. Similarly, after the first read sensor 111 detects (turns off) the trailing edge of the document being conveyed (S7), the image of the first reading unit 107 is detected after a predetermined time has elapsed (S8 after T2 conveyance). Reading is terminated (S9).
[0050]
Further, the document is transported through the transport path 104 and reaches a branch point with the switchback transport path 108, but the document contacts the guide member 90 provided in the switchback transport path 108 as shown in FIG. As a result, the guide member 90 is pressed by the document and elastically deforms downstream, so that the document can pass through the branch point in the direction of the conveyance path 104. Therefore, as shown in FIG. 8A, the document is conveyed through the conveyance path 104 as it is without being guided to the switchback conveyance path 108. The driving force of the motor is also transmitted to the discharge roller 106 disposed in the conveyance path 104, and the document is conveyed in the same manner as the conveyance roller 105.
[0051]
The branch sensor 112 detects the leading edge of the document being transported on the transport path 104 (S10), the document is further transported, and the branch sensor 112 detects the trailing edge of the document and outputs a detection signal (OFF). (S11) The image reading control unit receives the detection signal and stops the rotation of the motor. As a result, as shown in FIG. 8B, the document stops in a state where the document is nipped by the discharge roller 106 at a position where the trailing edge has passed the branch point. At this time, the leading edge of the document is discharged from the conveyance path 104, and a part of the document is projected onto the discharge tray 103.
[0052]
Thereafter, the motor is rotated in the reverse direction (S12), and the discharge roller 106 disposed in the conveyance path 104 and the discharge roller 106 disposed in the switchback conveyance path 108, as shown in FIG. Is rotated in the reverse direction, that is, in the direction of transport from the transport path 104 to the switchback transport path 108. The document conveyed in the reverse direction reaches the branch point at the rear end (upstream side of the conveyance path 104) and comes into contact with the guide member 90, but the guide member 90 is not elastically deformed as shown in FIG. The document is guided to the switchback conveyance path 108. As described above, when the document is switched back, a part of the document is projected from the conveyance path 104 onto the paper discharge tray 103, so that the most downstream from the branch point of the conveyance path 104 regardless of the size of the document. Can be set to a short distance, which contributes to the compactness of the image reading apparatus 100.
[0053]
As with the image reading of the first reading unit 107, the second reading unit 109 reads the image on the second surface of the document conveyed to the switchback conveying path 108. That is, the second read sensor 113 detects the original and outputs a detection signal (ON) (S13), and the image reading control unit receives the detection signal and then passes a predetermined time (after T3 conveyance, S14). 9B, as shown in FIG. 9B, image reading of the second reading unit 109 is started (S15), and after the OFF signal of the second read sensor 113 is output (S16), a predetermined time has elapsed ( After T4 conveyance, the image reading of the second reading unit 109 is finished in S17) (S18).
[0054]
As described above, by arranging the first reading unit 107 in the conveyance path 104 and the second reading unit 109 in the switchback conveyance path 109, the second reading unit 109 reads the second surface of the document. In this case, the trailing edge of the document has already passed the reading position of the first reading unit 107, and the image reading of the first reading unit 107 has been completed. Since the image reading circuit 109 does not overlap, the image processing circuit can be shared by the first reading unit 107 and the second reading unit 109, the circuit configuration can be simplified, and the apparatus can be made compact and the cost can be reduced.
[0055]
FIG. 14 is a block diagram showing an example of a circuit configuration until image data read by the first reading unit 107 and the second reading unit 109 are output to the main body control unit. The image data read by the second reading unit 109 is converted into digital data by the A / D conversion circuit and stored in the line memory, and the image data is subjected to image processing such as shading processing by the image processing circuit. It is configured to be output to the main body control unit.
[0056]
As described above, since the image reading of the first reading unit 107 and the image reading of the second reading unit 109 do not overlap, for example, the image data on the first surface and the image data on the second surface are processed simultaneously. Therefore, it is possible to switch and use one image processing circuit to sequentially process the image data of the first surface and the image data of the second surface and output them to the main body control unit. Thereby, the circuit configuration of the image reading apparatus 100 can be simplified and the cost can be reduced. For example, the first reading unit 107 and the second reading unit 109 share the A / D conversion circuit and the line memory by outputting a signal instructing the changeover switch to the A / D conversion circuit and the line memory. It is possible.
[0057]
As shown in FIG. 10, the original on which the double-sided image reading has been completed is discharged from the switchback conveyance path 108 to the discharge tray 103. Further, when the next document is present in the paper feed tray 101 (S19), the paper feed clutch is activated (S2), and the same operation as described above is repeated, so that the document placed on the paper feed tray 101 is detected. Documents are sequentially taken out from the bundle, and image reading from the first side to the nth side is performed.
[0058]
In addition, according to the image reading apparatus 100, the document transported back by the switch does not reach the reading position of the first reading unit 107. Therefore, after the image reading by the first reading unit 107 is finished, It is also possible to feed the document to be read next to the conveyance path 104 before completely completing the duplex reading. In that case, a motor for rotating the transport roller 105 and the like and a motor for rotating the discharge roller 106 are provided separately and the transport roller 105 is set in a fixed direction regardless of whether the discharge roller 106 rotates forward or reverse. What is necessary is just to comprise so that it can rotate.
[0059]
Further, according to the high-speed reading mode described above, the image reading on both sides of the document can be performed by one switchback conveyance, so that the document reading time is shortened as compared with the conventional case where the reversal is performed several times. In addition, since the document transport path is simplified, the occurrence of jams is reduced. In particular, the convenience of the high-speed reading mode is high when reading both sides of one or two originals.
[0060]
Next, the operation in the page alignment mode will be described with reference to FIGS.
In the above-described high-speed reading mode, although the reading time is short, the original discharged on the paper discharge tray 103 after the double-sided reading is finished is the upper side, for example, the first side when placed on the paper supply tray 101. However, the discharge tray 103 is also discharged on the upper side. Therefore, when a double-sided reading is performed on a plurality of documents, for example, as shown in FIG. 13A, the first, second, third, and fourth surfaces from the top of the paper feed tray 103 are used. If the originals discharged to the paper discharge tray 103 are collected as they are when they are the (n-1) th surface and the nth surface, the second surface, the first surface, the fourth surface, The third surface,..., The nth surface, and the (n-1) th surface, and the page order must be rearranged manually. The page alignment mode is for making such work unnecessary.
[0061]
As shown in FIG. 5, even in the page alignment mode, the operation until the second side of the document is read by the second reading unit 109 (S18) is the same as the high-speed reading mode described above. That is, when the start button of the operation unit is pressed, the image reading of the original is started, the original placed on the paper feed tray 101 is sent to the conveyance path 104, and the first reading unit 107 causes the first surface to be read. After the image is read, the image is conveyed to the switchback conveyance path 108 by switchback conveyance, and the image on the second surface is read by the second reading unit 109.
[0062]
After the OFF signal of the second read sensor 113 is output (S16) and after the predetermined time has elapsed (T4 transport, S17), the image reading of the second reading unit 109 is finished (S18). Stop rotating the motor again. As a result, as shown in FIG. 11A, the document stops after it has passed through the reading position of the second reading unit 109 and is nipped by the discharge roller 106. Also at this time, a part of the document is projected from the switchback conveyance path 108 onto the paper discharge tray 103. Therefore, when the document is switched back, the distance from the document reading position to the most downstream side of the switchback conveyance path 108 can be set short regardless of the size of the document, and the image reading apparatus 100 can be made compact. Can contribute.
[0063]
After that, the motor is rotated forward (S20), and the discharge roller 106 disposed in the switchback conveyance path 108 and the discharge roller 106 disposed in the conveyance path 104 are scanned as shown in FIG. Is rotated in the forward direction, that is, in the direction of transport from the switchback transport path 108 to the transport path 104. The leading edge of the document conveyed in the forward direction reaches the branch point, and as shown in FIGS. 3 and 12A, the document is guided by the guide member 90 and is downstream of the transport path 104 from the branch point. Guided to the side. Thereafter, as shown in FIG. 12 (b), the paper is discharged from the conveyance path 104 to the paper discharge tray 103.
[0064]
Further, when the next document is present in the paper feed tray 101 (S19), the paper feed clutch is activated (S2), and the same operation as described above is repeated, so that the document placed on the paper feed tray 101 is detected. Documents are sequentially taken out from the bundle, and image reading from the first side to the nth side is performed.
[0065]
As described above, according to the page alignment mode, the document whose image reading has been completed is discharged with the upper side of the original placed on the paper feed tray 101 being the lower side of the paper discharge tray 103, and thereafter Are also discharged and stacked on the discharge tray 103 in the same manner, the page order of the bundle of discharged documents is the same as the state of being placed on the paper feed tray 101. Therefore, it is not necessary to manually realign the pages as in the high-speed reading mode. In particular, the convenience of the page alignment mode is high when performing double-sided scanning of a large number of documents with continuous pages.
[0066]
In addition, since the user can arbitrarily select a high-speed reading mode for reading a document at high speed and a page alignment mode in which a page of the document after reading is in an original state, the image reading apparatus 100 can be used by the user. You can enjoy each advantage according to your needs.
[0067]
In the page alignment mode, the reading direction of the first side of the document is opposite to the reading direction of the second side. In general, when performing double-sided recording, the recording paper is constant with respect to the recording unit. Since the first surface and the second surface have different reading directions, it is necessary to invert one of the image data and output it to the recording unit. In order to avoid this, as shown in FIG. 15, a second read sensor 114 may be provided on the downstream side of the second reading unit 109 and controlled as follows.
[0068]
As described above, after the image on the first surface is read by the first reading unit 107, the document conveyed to the switchback conveyance path 108 by the switchback conveyance is the second as shown in FIG. The image is further read back without being read. The second read sensor 114 detects the document transported back and outputs an off signal when the document passes. In response to this, the image reading control unit stops the rotation of the motor, and the document is stopped in a state where it is nipped by the discharge roller 106 as shown in FIG.
[0069]
Thereafter, the motor rotates forward, and the discharge roller 106 disposed in the switchback conveyance path 108 and the discharge roller 106 disposed in the conveyance path 104 convey the document in the forward direction. The second read sensor 114 that has detected the document again outputs an ON signal. Upon receiving the ON signal, the image reading control unit reads the image of the second reading unit 109 as shown in FIG. The image reading of the second reading unit 109 is terminated after a predetermined time has elapsed since the second read sensor 114 outputs an OFF signal. Thereafter, the document is further conveyed and reaches the branch point, is guided by the guide member 90, is guided from the branch point to the downstream side of the conveyance path 104, and is discharged as shown in FIG. It is discharged to the tray 103.
[0070]
By controlling in this way, the reading direction of the first side of the original and the reading direction of the second side can be read in the same direction, that is, both sides can be read from the same end of the original. When printing the image data read by each of the two reading units 109, it is not necessary to invert the image. Therefore, a circuit for inverting the image data is not necessary, and the circuit configuration for processing the image data can be further simplified.
[0071]
【The invention's effect】
  As described above, according to the image reading apparatus of the present invention, the conveying unit that conveys the document placed on the sheet feeding tray to the discharge tray side through the conveying path, and the conveying unit that is arranged and conveyed on the conveying path. A first reading unit that reads an image on the first side of a document that is on the left side of the first reading unit;To communicate with the output trayA switchback conveyance path provided; a second reading unit configured to read an image on a second surface of the document that is arranged and conveyed in the switchback conveyance path; After transporting to the downstream side of the branch point, the document is fed back and sent to the switchback transport pathThen, the document whose second side is read is discharged from the switchback conveyance path to the discharge tray.As described above, since the control means for controlling the conveying means is provided, the image reading of the first reading means and the image reading of the second reading means do not overlap. Therefore, it is possible to share an image processing circuit for processing image data read by each reading unit, and it is possible to reduce the cost and the size of the apparatus. In addition, the conveyance path is simplified and jamming or the like is less likely to occur. Further, since the switched-back document does not reach the reading position of the first reading means, it is possible to supply the next document to be read to the conveyance path after the first surface of the document has been read. The speed can be increased.Also, the first and second sides of the document can be read with a single switchback, and the reading speed is increased.
[0074]
In addition, according to the present invention, the high-speed reading mode (first control) and the page alignment mode (second control) can be selected, so that the setting according to the usage mode of the user is possible.
[0075]
Further, according to the present invention, the paper feed tray and the paper discharge tray are vertically arranged at predetermined intervals, and the switchback transport path is formed in the space between the paper feed tray and the paper discharge tray. Space can be used, and the image reading apparatus can be made compact.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of an image reading apparatus 100 according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating control of the image reading apparatus 100. FIG.
FIG. 3 is an enlarged view showing a configuration in the vicinity of a branch point of a switchback transport path 108;
FIG. 4 is a flowchart showing the operation of the image reading apparatus 100 in a high-speed reading mode.
FIG. 5 is a flowchart showing the operation of the image reading apparatus 100 in the page alignment mode.
FIG. 6 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in a high-speed reading mode.
FIG. 7 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in a high-speed reading mode.
FIG. 8 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in a high-speed reading mode.
FIG. 9 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in a high-speed reading mode.
10 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in a high-speed reading mode. FIG.
FIG. 11 is a schematic diagram illustrating a document conveyance state when the image reading apparatus 100 reads a document in the page alignment mode.
FIG. 12 is a schematic diagram illustrating a document transport state when the image reading apparatus 100 reads a document in the page alignment mode.
FIG. 13A is a schematic diagram showing a reading order when reading a document from the top sheet, and FIG. 13B is a schematic diagram showing a reading order when reading a document from the bottom sheet. It is.
14 is a block diagram illustrating an example of a circuit configuration until image data read by the first reading unit 107 and the second reading unit 109 is output to the main body control unit. FIG.
15 is a cross-sectional view showing a modification of the image reading apparatus 100. FIG.
FIG. 16 is a schematic diagram illustrating a document conveyance state in a modified example.
FIG. 17 is a schematic diagram illustrating a document conveyance state in a modified example.
18 is a schematic diagram for explaining a configuration of a conventional sheet-through type image reading apparatus 800. FIG.
FIG. 19 is a schematic diagram for explaining the operation of a conventional sheet-through type image reading apparatus 800;
20 is a schematic diagram for explaining the operation of a conventional sheet-through type image reading apparatus 800. FIG.
[Explanation of symbols]
100 Image reading apparatus
101 Paper tray
103 Output tray
104 Transport path
105 Conveying roller (conveying means)
106 Discharge roller (conveyance means)
107 First reading unit (first reading means)
108 Switchback transport path
109 Second reading unit (second reading means)

Claims (3)

Transport means for transporting the document placed on the paper feed tray to the discharge tray side through the transport path;
First reading means for reading an image of a first surface of a document which is arranged and conveyed in the conveyance path;
A switchback conveyance path provided so as to diverge from the conveyance path on the downstream side of the first reading means and communicate with a discharge tray ;
A second reading means for reading an image on the second surface of the document which is arranged and conveyed in the switchback conveyance path;
When performing double-sided reading of a document, the document is transported to the downstream side of the branch point of the transport path, and then the document is reversely fed and sent to the switchback transport path, and the document whose second surface is read is switched back. An image reading apparatus comprising: a control unit that controls the transport unit so as to discharge the paper from a transport path to a paper discharge tray . Transport means for transporting the document placed on the paper feed tray to the discharge tray side through the transport path;
First reading means for reading an image of a first surface of a document that is arranged and transported in the transport path;
A switchback conveyance path provided so as to branch from the conveyance path on the downstream side of the first reading unit and communicate with the discharge tray;
A second reading means for reading an image on the second surface of the document which is arranged and conveyed in the switchback conveyance path;
When performing double-sided scanning of a document, the document is transported to the downstream side of the branch point of the transport path, and then the document is reversely fed and sent to the switchback transport path. The conveying means is configured to discharge the original from the conveying path to the paper discharge tray, or to discharge the original to the paper discharge tray through the conveying path after the second reading means has read the second surface of the original. An image reading apparatus comprising a control means for selectively controlling. The paper feed tray and the paper discharge tray are vertically arranged at predetermined intervals, and the switchback transport path is formed in a space between the paper feed tray and the paper discharge tray. The image reading apparatus according to claim 1 or 2.

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