JP2006168972A - Image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a reading face facing upward from being damaged, in an image reading device having an automatic document carrying device and capable of reading images on both faces of documents. <P>SOLUTION: A first branch path 25a which goes through a first reading position 23 and a second branch path 25b which does not go through the first reading position 23 are provided on a document carrying path 25, and a document is guided to either of the branch paths 25a, 25b by a first carrying guide 22k and a second carrying guide 22l. In a both-face reading mode, the document is carried on the first branch path 25a. At this time, an image on one face of the document is read in the first reading position 23 by a first reading device 30, and an image on the other face of the document is read in a second reading position 24 by a second reading device 26. In a one-face reading mode, the document is carried on the second branch path 25b, and the image on one face of the document is read in the second reading position 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus including an automatic document feeder and capable of reading images on both sides of a document.

  An image reading apparatus used to capture image data into a copying machine, a facsimile machine, or a computer includes an automatic document conveying device that automatically conveys a document and a reading device provided along a document conveying path. It has been. In such an image reading apparatus, since the document is sequentially read from the leading end portion in the document conveyance direction by a fixed reading apparatus, dust and dust adhering to the reading surface of the reading apparatus are recognized as an image of the document and are read. It appears as black streaks in the data.

  As an image reading apparatus in which dust and dust are unlikely to adhere to the reading surface of the reading apparatus, in Patent Document 1, the image reading apparatus is arranged so that the reading surface of the reading apparatus (contact image sensor) faces downward and is in contact with the document conveyance path. Has been proposed.

  On the other hand, when the reading surface of the reading device is facing upward, dust and dust adhering to the reading surface fall from the conveyed paper. Therefore, in Patent Document 2, dust attached to the conveyed paper by providing a charging member, a brush, or the like. An image reading apparatus that removes dust in front of a reading surface has been proposed.

Further, as an apparatus capable of reading images on both sides of a document at one time, for example, as shown in Patent Document 3, an apparatus having two reading devices with a reading surface facing upward and downward along a document conveyance path is used. ing. By providing this with the brush proposed in Patent Document 2, dust and dust adhering to the reading surfaces of both reading devices can be reduced, and black streaks can be hardly generated.
Japanese Patent No. 3124133 (second page, FIG. 1) Japanese Patent Laying-Open No. 2003-206045 (5th page, FIGS. 1 and 6) JP-A-11-69086 (3rd page, 4th page, FIG. 1)

  Incidentally, even in an image reading apparatus capable of reading images on both sides of a document, such as the image reading device proposed in Patent Document 1, only on one side of the document, compared to the case where images are attached to both sides of the document. In many cases, an image is attached and only one of the two reading devices is used. In most cases, one reading device used at this time has an upward reading surface on which dust and dirt are likely to fall and adhere.

  In such an image reading device, the reading surface of the reading device with the reading surface facing upward can reduce the amount of dust and dust adhering thereto by providing the above-described brush and the like. However, since all the conveyed documents are rubbed by gravity, the coating applied to the glass surface of the reading surface is deteriorated and easily damaged, and black streaks of the image due to this may occur.

  Therefore, in the present invention, even if no special member is provided, dust and dust are unlikely to adhere to any reading surface of the two reading devices, and the reading surface of the reading device with the reading surface facing upward is not easily damaged. An object of the present invention is to provide an image reading apparatus capable of reading images on both sides of a document at once.

  In order to achieve the above object, the present invention provides a document conveying means for conveying a document from a document placing tray to a document discharge tray, and an image on one side of the document along a document conveyance path through which the document is conveyed. An image reading apparatus comprising a first reading device for reading and a second reading device for reading an image on the other side of the document, wherein the second reading device is disposed with the reading surface facing downward. An image sensor, wherein the document conveying path is between the document placing tray and the second reading device, the first branch path passing through the first reading device and the second not passing through the first reading device; In the double-sided reading mode, the original is conveyed through the first branching path, and both sides of the image are read by the first reading device and the second reading unit. In the single-sided reading mode, the original is Is transported through the second branch Images on one side by a reader, characterized in that the read of the.

  According to the present invention, the original is conveyed along the first branch path in the double-sided reading mode, and the images on both sides of the original are read at a time by the first reading device and the second reading device, and in the single-sided reading mode, the first image is read. Since the original is not in contact with the first reading device that is transported through the two conveyance paths and is not used, the original does not contact the reading surface of the first reading device more than necessary. Accordingly, it is possible to obtain an image reading apparatus that can read images on both sides of the document at one time, with which the reading surface of the first reading apparatus is hardly damaged.

  An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram of a copying machine provided with an image reading apparatus according to the present invention, and FIG. 2 is a partially enlarged view in the vicinity of a document conveying portion.

  First, the configuration and operation of each part of the copying machine 10 will be described. The copying machine 10 includes a main body 11 and a document conveying device 20 placed above the main body 11. A control device 13 for controlling the entire operation of the copying machine 10 such as an image forming operation, an image reading operation, and a document conveying operation is provided on the upper portion of the main body 11. Further, an outer discharge tray 82 that can be manually opened and closed in a closed state indicated by a broken line and an open state indicated by a solid line is attached to the central portion of the left side surface of the main body 11. An inner discharge tray 84 is provided.

  The document feeder 20 is attached to the main body 11 so that it can be opened and closed with the back side of the paper as a fulcrum. The document transport device 20 includes a document placement tray 21, a document transport unit 22, a document discharge tray 27, and a document cover 28. The document discharge tray 27 is integrally formed as a part of the upper surface of the document cover 28. The document placing tray 21 forms the upstream end of the document conveying path 25, and the document discharge tray 27 forms the downstream end of the document conveying path 25.

  The document transport unit 22 includes, in order from the upstream side in the document transport direction along the document transport path 25, a forward feed roller 22a, a paper feed roller 22b, a separation roller 22c, a registration roller pair 22d, a first transport roller pair 22e, Two conveyance roller pairs 22f, a first reading guide 22g, a third conveyance roller pair 22h, a second reading guide 22i, and a discharge roller pair 22j are provided. A second reading device 26 including a contact image sensor is disposed at a position facing the second reading guide 22 i with the document conveyance path 25 interposed therebetween. Further, the first image reading position 23 is set to a position facing the first reading guide 22g on the upper surface of the transparent glass platen 12 on the upper surface of the main body 11, and the second image reading position 24 is set to the second image reading position 24. Is set on the surface of the reading device 26 facing the document conveyance path 25.

  In the case of a so-called sheet-through method, when a copy start button (not shown) is pressed, the document C set with images on both sides set on the document placing tray 21 is transported through the document transport path 25 by the respective rollers. An image on one side is read at a first image reading position 23 by a first reading device 30 to be described later, and an image on the other side is read by a second reading device 26 at a second image reading position 24. . The original C is brought into contact with the first image reading position 23 by the first reading guide 22g and the second image reading position 24 by the second reading guide 22i so that the read image is in focus. It is conveyed so that it touches. In the case of the document fixing method, the document (not shown) placed on the stationary document reading position 29 set on the upper surface of the platen 12 and pressed by the document cover 26 has an image on the surface in contact with the platen 12. 1 reading device 30.

  The first reading device 30 is disposed on the upper portion of the main body 11, and includes an exposure lamp 31, a reflecting plate 32, a first mirror 33, a second mirror 34, a third mirror 35, a condensing lens 36, an image. A sensor (for example, a line type CCD) 37 is provided. The exposure lamp 31 and the first mirror 33 are mounted on a carriage 38 and are provided so as to be horizontally movable in FIG.

  When reading the image of the document C conveyed by the sheet-through method, the carriage 38 moves directly below the first image reading position 23 to expose the document C to which the irradiation light from the exposure lamp 31 is conveyed. . The irradiation light is reduced and imaged on the image sensor 37 through the first mirror 33, the second mirror 34, the third mirror 35, and the condenser lens 36, and is read out as an electric signal through a photoelectric conversion process. This electrical signal is sent to the control device 13. On the other hand, when reading the image of the document by the document fixing method, the exposure lamp 31 and the first mirror 33 on the carriage 38 that moves to the right in FIG. By reading and scanning the original, the irradiation light is reduced and imaged on the image sensor 37 and is read to be an electric signal through a photoelectric conversion process as in the case of the sheet-through method. 13.

  Also in the second reading device 26, the original image is read so as to be an electric signal only in the case of the sheet through method, and this electric signal is sent to the control device 13.

  Below the main body 11, a paper feeding device 50, an image forming unit 60, and a fixing device 70 are provided. First, the sheet feeder 50 will be described. A paper feed cassette 51 that accommodates paper P is disposed at the bottom of the main body 11, and the paper P is fed from the paper feed roller 52 to the transport path e one by one from here, and a transport roller pair 53 and a registration roller pair 54. Is conveyed to the image forming unit 60.

  Next, the image forming unit 60 will be described. The image forming unit 60 includes a photosensitive drum 61 and a charger 62, an optical scanning unit 63, a developing device 64, a transfer roller 65, and a cleaning device 66 disposed around the photosensitive drum 61. The photosensitive drum 61 rotates clockwise in FIG. 1, and the surface thereof is first uniformly charged by the charger 62. Next, the surface of the photosensitive drum 61 is irradiated with laser light from the optical scanning unit 63 based on the electrical signal of the image read by the first reading device 30 or the second reading device 26 and sent to the control device 13. Then, the charge corresponding to the portion of the image formed on the paper P or the portion other than the image is erased, and an electrostatic latent image is formed. Then, toner is supplied to the electrostatic latent image by the developing device 64, and the electrostatic latent image is visualized as a toner image.

  When the photosensitive drum 61 further rotates and the toner image comes to a position facing the transfer roller 65, the sheet P is conveyed between the photosensitive drum 61 and the transfer roller 65 by the registration roller pair 54 accordingly. It will be. At this time, the toner image on the surface of the photosensitive drum 61 is transferred onto the paper P by applying a voltage having a polarity opposite to the charging polarity of the toner to the transfer roller 65. The toner remaining on the surface of the photosensitive drum 61 without being transferred to the paper P is removed by the cleaning device 66.

  On the other hand, the paper P onto which the toner image has been transferred is conveyed to a fixing device 70 comprising a heating roller 71 and a pressure roller 72, where the toner image is heated and pressurized and fixed on the paper P. Thereafter, the paper P is guided toward the in-cylinder discharge tray 82 or the in-cylinder discharge tray 84 which is selected in advance by a user by a paper guide 75 which is rotatably provided by a solenoid (not shown). Further, the surface on which the image is formed by the discharge roller pair 81 is discharged to the outside discharge tray 82, and the surface on which the image is formed by the discharge roller pair 83 is directed downward to the in-body discharge tray 84. Discharged.

  In the present embodiment, the document transport path 25 of the document transport apparatus 20 is configured such that the first branch path 25a and the second branch path 25b are between the first transport roller and the third transport roller, as shown in FIG. It is branched to. A first conveyance guide 22k is provided immediately downstream of the first conveyance roller 22e in the document conveyance direction, and a second conveyance guide 22l is provided immediately upstream of the third conveyance roller 22h in the document conveyance direction. It has been. Both the first conveyance guide 22k and the second conveyance guide 22l can be rotated around their respective axes by a solenoid or a motor (not shown) to change the posture.

  In the double-sided reading mode in which both-side images of the original C conveyed by the original conveying device 20 are read, the first conveying guide 22k and the second conveying guide 22l take the double-sided reading posture shown by the solid line in FIG. Is guided to the third conveying roller 22h via the first branch path 25a. At this time, one side of the conveyed document C is read by the first reading device 30 at the first image reading position 23 and the other side is read by the second reading device 26 at the second image reading position 24. .

  On the other hand, in the single-sided reading mode in which an image of only one side of the original C conveyed by the original conveying device 20 is read, the original C is placed on the original placing tray 21 with the surface to be read facing downward. The first conveyance guide 22k and the second conveyance guide 22l take a single-sided reading posture indicated by a broken line in FIG. 2, and take a posture for guiding the document to the second branch path 25b and the third conveyance roller 22h. In this way, the conveyed document C is read only at the second image reading position 24 by the second reading device 26 with its surface facing downward on the document placing tray 21.

  With this configuration, in the single-sided reading mode, the document C does not pass through the first image reading position 23 on the platen 12 because it does not pass through the first image reading position 23 that is not used for image reading. Dust and dust do not fall off, and the original C is not rubbed and scratched. That is, dust and dirt from the original C are dropped at the first image reading position 23, and the original C is rubbed and scratched only in the double-sided reading mode.

  Here, when a plurality of documents C are sequentially stacked, they are transported and read sequentially from the back by the document transport device 20. In the copying machine 10 according to the present embodiment, the sheet P has the surface on which the image is formed facing upward on the out-cylinder discharge tray 82 and the surface on which the image is formed facing down on the in-cylinder discharge tray 84. Discharged. Therefore, in order to align the order of the document C and the order of the sheets P, when the sheets are discharged onto the out-body discharge tray 82, the images may be formed on the sheets P in the order in which the documents C are read. On the other hand, when discharging onto the in-body discharge tray 84, all of the stacked originals C are conveyed and stored in the control device 13, and then images are formed on the paper P in the same order as the order of the originals C. Then, it may be discharged onto the discharge tray 82.

  Further, a brush or a charging member (not shown) may be provided in front of the first image reading position 23 in the paper transport path 25 to remove dust and dust from the original C. Accordingly, it is possible to prevent dust and dust from dropping from the original C to the first image reading position 23 even in the double-sided reading mode.

  The present invention can be used in an image reading apparatus that includes an automatic document feeder and can read images on both sides of a document.

Schematic configuration diagram of a copying machine equipped with an image reading apparatus according to the present invention Partial enlarged view of the vicinity of the document feeder

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Copy machine 20 Original conveying apparatus 21 Original loading tray 22 Original conveying part 25 Original conveying path 25a First branch path 25b Second branch path 26 Second reading apparatus 27 Original discharge tray 30 First reading apparatus

Claims (1)

Document conveying means for conveying the document from the document placing tray to the document discharge tray, a first reading device for reading an image on one side of the document along the document conveyance path through which the document is conveyed, and the document A second reading device that reads an image on the other side of the image reading device,
The second reading device is a contact type image sensor arranged with a reading surface facing downward, and the document transport path passes between the document loading tray and the second reading device via the first reading device. Branching into a first branch path and a second branch path that does not pass through the first reading device, and in the double-sided reading mode, the document is conveyed along the first branch path, and the first reading device and the first branching path are 2. An image reading apparatus, wherein two-sided images are read by the two reading means, and in the single-sided reading mode, the original is conveyed on the second branch path and an image on one side is read by the second reading device.

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