JP2011066616A - Image reader and document feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader wherein foreign substances such as dirt and dust adhering to the actual reading surface can be removed easily. <P>SOLUTION: In the image reader, a white member 103, which is provided on the pressure plate side of a platen nip portion and is available as a white reference at the time of reading, serves as a vibrator. The image reader directly vibrates a platen glass 407 in contact with the white member 103 through the platen nip portion by vibrating the white member 103 itself arranged on the optical path at the reading position, and scatters the foreign substances by reducing adhesion of the foreign substances such as dirt and dust. Furthermore, the image reader scrapes off the scattered foreign substances at the tip of an original 101. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an original conveying apparatus that read an image of an original conveyed to a transparent member.

  Conventionally, an image reading apparatus reads an original image by placing an original conveyed by an automatic original conveying apparatus on an original table glass and scanning an optical system for reading in a predetermined direction. This reading method is a so-called fixed reading method.

  There is also known a so-called flow reading method in which an optical system for reading is fixed and an original image is read while an original is being conveyed by an automatic document conveying device. However, when dust enters the platen nip portion on the platen glass from the outside, there are the following problems. Since the optical system is fixed, the image reading apparatus continues to read the same dust. As a result, an image as if it is a straight line is read by dust and processed as an abnormal image as it is.

  In addition, when the user directly touches the outer surface of the platen glass and gets dirty with sebum or the like and becomes clouded, the sharpness of the read image is lowered. Further, the outer surface of the platen glass is often stained with organic compounds such as cigarette dust and mold. For this reason, the foreign material was removed by the user cleaning.

  Conventionally, Patent Document 1 discloses an image reading apparatus as described below as a method for removing foreign matter without depending on human hands. The image reading apparatus includes an automatic document feeder and a reader unit. This image reading apparatus includes a transmissive member (ADF document platen glass) disposed between a document transport path of an automatic document feeder and a scanner unit so as to transmit a document image separately from a document table glass. . Further, the image reading apparatus includes a vibration generating unit (piezoelectric vibrator) for applying vibration to the transmissive member and a driving unit for driving the vibration generating unit, and performs a predetermined instruction or a predetermined operation on the image reading apparatus. In response, the vibration generator is driven to move the dust.

  Patent Document 2 discloses the following image reading apparatus. The image reading apparatus includes one or a plurality of electromechanical conversion elements (vibrating bodies) coupled to a transmission member (platen glass), and a voltage supply unit that applies a high-frequency voltage to the electromechanical conversion elements via electrodes. Have. Further, the image reading apparatus includes a control unit that excites vibrations in the transmissive member by one or a plurality of electromechanical conversion elements and a voltage supply unit.

JP 2003-280110 A JP 2004-12474 A

  However, the conventional image reading apparatus has the following problems. That is, a vibrating body that vibrates a transmitting member such as a platen glass is provided at an end portion in the main scanning direction that is out of the platen nip portion of the reading unit so as not to block the optical path during reading.

  Further, since the vibrating body vibrates the back side, which is the opposite side to the surface on which dust is attached, the surface of the platen nip portion, which is the actual reading surface, cannot be vibrated directly. Therefore, dust removal by vibration is limited and insufficient.

  SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus and an original conveying apparatus that can easily remove foreign matters such as dust and dust attached to an actual reading surface.

  In order to achieve the above object, an image reading apparatus according to the present invention is an image reading apparatus that reads an image of a document conveyed between a transparent member and a guide member by a document conveying unit by the reading unit via the transparent member. And a vibration means for vibrating the guide member so that the guide member contacts the transparent member.

  According to the image reading apparatus of the first aspect of the present invention, since the guide member is vibrated so that the guide member contacts the transparent member, foreign matters such as dust and dust attached to the transparent member can be easily obtained. Can be removed.

  According to the image reading apparatus of the second aspect, the vibrating body is vibrated between the preceding document conveyed to the transparent member and the succeeding document, so that foreign matter can be removed without reducing the document reading productivity. Is possible.

  According to the image reading apparatus of the third aspect, when it is determined that there is a foreign object, the vibrating body is vibrated, so that it is not necessary to vibrate the vibrating body unnecessarily.

  According to the image reading apparatus of the fourth aspect, since the guide member is a white member, space is saved without providing it as a separate member, and an increase in the number of parts can be suppressed.

  According to the image reading apparatus of the fifth aspect, since the shim material is used as a part of the guide member, the surface of the transparent member can be vibrated without being damaged.

  According to the image reading apparatus of the sixth to eighth aspects, organic matter on the transparent member can be removed or its adhesion can be reduced by the photocatalytic action.

1 is a cross-sectional view illustrating an internal configuration of an image reading apparatus according to an embodiment. 2 is a block diagram illustrating an electrical configuration of the image reading apparatus. FIG. It is a figure which shows the structure of the reading position vicinity of an image reading apparatus. It is a figure which shows the internal structure of the white member. FIG. 6 is a diagram illustrating a standby state other than a reading operation and a state of the white member 103 during document conveyance. It is a figure which shows the state of the white member 103 at the time of reading operation. 6 is a flowchart illustrating a procedure of a document conveying operation in a normal operation. FIG. 8 is a flowchart showing a document transport operation procedure in a normal operation following FIG. 7. FIG. 6 is a flowchart illustrating a document transport operation procedure in an avoidance operation when dust is detected.

  Embodiments of an image reading apparatus and an original conveying apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an internal configuration of an image reading apparatus according to an embodiment. The image reading device 50 mainly includes a document conveying device 60 and an image reading unit 70. The image reading apparatus 50 includes a stacking tray 1 on which a plurality of originals 101 are placed, and a pickup roller 2 that feeds the uppermost original of the original bundle into the apparatus. When the feeding operation starts, the image reading device 50 lowers the pickup roller 2. The documents fed by the pickup roller 2 are separated one by one by the feed roller 4 and the retard roller 5.

  The separated document 101 is conveyed through the drawing roller 6 and the conveying roller 13. The document that has passed through the transport roller 13 is transported downstream and abutted against the registration roller 15. The registration roller 15 forms a loop in the document, and the skew of the leading edge of the document is eliminated. The document that has passed through the registration roller 15 passes through the upstream conveying roller 405 and is sent to the white member 103 to be conveyed on the document table glass 407 (on the transparent member).

  The white member 103 is disposed at a reading position in the conveyance path, faces the document table glass 407, and also has a function as a guide member that presses the document to be conveyed against the document table glass 407. A reading device 102 that is movable in the horizontal direction by a guide shaft 410 is provided inside the platen glass 407. The reading device 102 reads an image of the conveyed document at a reading position facing the white member 103 with the document table glass 407 interposed therebetween. The document that has passed through the white member 103 passes through the conveyance roller 405 on the downstream side. The document fed by the conveyance roller 405 on the downstream side is discharged to the document discharge tray 25 by the discharge roller 24.

  In addition, the image reading apparatus reads the white member 103 by the reading device 102 before reading the document, thereby creating white level reference data of the surface image by shading. Further, the stacking tray 1 is provided with a document size detection unit 413 that detects the presence or absence of a document.

  FIG. 2 is a block diagram showing an electrical configuration of the image reading apparatus. In the figure, a reading device (line image sensor) 102 includes a CIS (contact image sensor) that reads an image of a sheet-like document 101 set in an image reading apparatus. The white member 103 is disposed on a surface facing the line image sensor 102 and serves as a white reference at the time of reading. In the present embodiment, the white member 103 has a function as a vibrating body that generates vibration.

  An automatic document feeder (ADF) 104 drives a conveyance motor 112 to continuously convey a sheet-like document 101. The moving unit 105 horizontally moves the line image sensor 102 in the sub-scanning direction. A reading control unit 106 is connected to the system bus 121 and controls the entire image reading apparatus. Further, the reading control unit 106 sends a drive signal to the white member 103 to vibrate the white member 103.

  The image memory 107 stores image information output from the line image sensor 102 in units of pages. The image buffer 108 includes a FIFO, and temporarily stores the image output from the image input unit 116.

  The CPU 109 controls the entire image reading apparatus including the reading control unit 106. The ROM 110 stores a program executed by the CPU 109. The RAM 111 is accessed by the CPU 109. The conveyance motor 112 drives a plurality of conveyance rollers to continuously convey the sheet-like document 101. The movement motor 113 drives the guide shaft 410 to continuously move the line image sensor 102 horizontally in the sub-scanning direction.

  The shading plate 114 is used for determining a white reference and a shading correction value of the image reading apparatus. The operation unit 115 operates and displays the image reading apparatus, and includes an activation button (start button) such as reading start. The image input unit 116 inputs image information output from the line image sensor 102.

  FIG. 3 is a diagram showing a configuration near the reading position of the image reading apparatus. The upstream and downstream transport rollers 405 transport the document 101. The document table glass 407 can also be loaded with a book-type document, and is sandwiched between the reading device 102 and the document 101.

  The transport motor 112 drives and rotates the upstream and downstream transport rollers 405. The moving motor 113 horizontally moves the reading device 102 in the sub scanning direction by the guide shaft 410. The guide shaft 410 converts the rotational motion of the moving motor 113 into a straight motion.

  The home position 411 indicates the position of the reading device 102 when reading the shading plate 114. A reading position 412 indicates an actual reading position at a position where the reading device 102 is movable, that is, at a movable step position.

  As described above, the document size detection unit 413 is provided on the stacking tray 1 and includes a photo interrupter that detects the document 101. In this embodiment, the document is a document fixed to A4 size. Accordingly, the document size detection unit 413 only detects “presence / absence” of the document by the photo interrupter.

  When the user sets the document 101 in the image reading apparatus and presses the start button of the operation unit 115, the reading control unit 106 detects that the start button has been pressed.

  The reading control unit 106 issues a reading operation start instruction to the document conveying unit 104. The document conveying unit 104 sets a predetermined number of pulses and rotates the conveyance motor 112 to start conveying the document 101. As a result, an actual image reading operation starts.

  The reading device 102 includes therein an LED array (light source), a rod lens array, a photo sensor array (imaging means), and a circuit that transfers an output signal from the photo sensor. The reading device 102 irradiates the image surface of the document 101 with the LED array, collects the reflected light corresponding to the density difference of the document 101 on the photosensor array with the rod lens array, and generates an image. The reading device 102 transfers the image signal output from the photosensor array to the image input unit 116 as serial data.

  The image input unit 116 outputs the image signal to the image buffer 108 as serial data for one line of image data. The image buffer 108 stores this image signal in the image memory 107 as needed via the system bus 121. Thereafter, when the document 101 passes through the reading device 102 and is discharged, the document transport unit 104 stops the transport motor 112. Thereby, the original reading operation for one page is completed. The read image is finally stored in the image memory 107 in units of pages.

  In the present embodiment, when foreign matter such as dust or dust enters the platen nip portion of the reading unit, the reading control unit 106 outputs a drive signal to vibrate the white member 103. The white member 103 may be configured by joining a vibrating body to the white member 103, or may be configured such that the white member 103 itself vibrates as a vibrating body.

  In a normal image reading operation, when the document 101 is set in the image reading apparatus, the document size detecting unit 413 detects the presence or absence of the document. In the present embodiment, as described above, the document size is fixed to A4 size.

  When the document 101 is detected, the reading device 102 moves from the home position 411 to the reading position 412 when actually starting the reading operation. In this movement, the moving motor 113 rotates by a predetermined number of pulses, and the guide shaft 410 converts the rotational motion of the motor into a straight motion. As a result, the reading device 102 moves to the set reading position 412. When the reading device 102 is already at the reading position 412, the moving motor 113 does not rotate and does not move the reading device 102.

  Then, the conveyance motor 112 is rotated to rotate the upstream conveyance roller 405 to convey the document 101 to the position of the reading device 102, and then the image reading operation is started. At this time, the reading device 102 is disposed at a position facing the white member 103.

  In the sub-scanning direction, the reading device 102 is movable by converting the rotational driving force of the moving motor 113 into a straight driving force via the guide shaft 410. In the present embodiment, the home position 411 of the reading device 102 is a position close to the carry-in portion of the document 101 facing the white member 103.

  When the document 101 is transported by the upstream and downstream transport rollers 405 while being read, and is discharged after passing through the position of the reading device 102, the transport motor 112 is stopped and a one-page document reading operation is performed. Is completed. Then, the reading device 102 is returned to the home position 411 again by the moving motor 113.

  Next, an image reading operation in the case where an image is affected by foreign matters such as dust and dust will be described. The document 101 sent out by the upstream-side transport roller 405 is transported in close contact so as to rub on the document table glass 407 on which the photocatalyst coating 515 is applied. At this time, the reading device 102 reads the image information of the document 101. At this time, if there is foreign matter such as dust on the optical path, the read image is processed as an abnormal image as if the foreign matter is a straight line.

  Therefore, in the present embodiment, in order to reliably remove foreign matter on the optical path, organic matter contamination on the platen glass 407 is accelerated by photocatalysis by irradiation from the light source of the reading device 102 and decomposed. To remove or reduce its adhesion. As described above, in the present embodiment, as the photocatalyst coating 515, the surface of the platen glass 407 is coated with a photocatalytic substance. As the photocatalytic substance, titanium oxide or a composite oxide containing titanium oxide can be given. Further, the light source has a light source in a wavelength region that causes the catalytic reaction of the photocatalytic substance to proceed.

  Further, regarding inorganic stains on the platen glass 407 and the white member 103, the white member 103 is vibrated so that the white member 103 contacts the platen glass 407, thereby reducing the adhesion of the stain.

  Finally, when the document 101 is read and conveyed, the front end of the document 101 is brought into close contact with the document table glass 407 so that the scattered foreign matter is removed so as to be scraped off from the reading surface.

  Here, the portion to be vibrated is not limited to the original platen glass 407, but may include the shading plate 114 on the optical path. The white reference portion 521 of the white member 103 may be white-coated at the nip portion on the optical path, or may be a white tape attached.

  FIG. 4 is a diagram showing an internal configuration of the white member 103. As described above, the white member 103 is a white member that is disposed on the surface facing the line image sensor 102 via the document table glass 407 and serves as a white reference at the time of reading. In the present embodiment, the white member 103 has a function as a vibrating body and a function as a guide member that presses the document against the document table glass 407.

  The white member 103 includes a piezoelectric ceramic 503, a metal shim material 516 that is an elastic plate, a first electrode 517, a second electrode 518, and a white reference portion 521. The piezoelectric ceramic 503 is a solid displacement element having a property of being distorted when a voltage is applied. The first electrode 517 is provided on the piezoelectric ceramic 503. The second electrode 518 is provided on the shim material 516. Each of the first electrode 517 and the second electrode 518 is formed by an evaporation method, a sputtering method, a plating method, a metal (silver, silver-palladium, platinum) paste method, or the like.

  The shim material 516 can be vibrated by continuously applying forward and reverse voltages to both ends of the first electrode 517 and the second electrode 518 repeatedly. The white reference portion 521 has a white color determined so as to be a white reference of the image reading apparatus, and may have a white tape attached as described above.

  In the drawing, the first reference point 519 corresponds to the position of the leading edge of the document 101 when it is fed by the upstream conveying roller 405 and reaches the document table glass 407. Similarly, the second reference point 520 corresponds to the position of the trailing edge of the document 101 when the document reading is completed.

  The white member 103 has a bimorph structure in which one side of a metal shim material 516 bent at 180 degrees is sandwiched between piezoelectric ceramics 503. By applying a bidirectional repetitive voltage between the first electrode 517 and the second electrode 518, the metal shim material 516 vibrates. The white member 103 can reduce the adhesion force of the foreign matter adhering to the optical path of the white reference portion 521 by vibration, and can disperse the foreign matter.

  Further, the white member 103 vibrates so as to come into contact with the platen glass 407, so that the platen glass 407 is also vibrated at the same time, and similarly, the adhesion force of the foreign matter adhering to the optical path can be reduced and the foreign matter can be scattered. Is possible. Here, by setting the bent side of the metal shim material 516 to the insertion direction of the original 101, the original 101 conveyed by the upstream conveying roller 405 is guided (guided), and the original 101 is further guided by the original table glass 407. It is possible to function as a guide member that is pressed into the guide.

  FIG. 5 is a diagram illustrating a standby state other than the reading operation and a state of the white member 103 during document conveyance. In this state, between the shim material 516 and the piezoelectric ceramic 503 via the first electrode 517 and the second electrode 518, the shim material 516 is distorted upward, that is, the piezoelectric ceramic 503 is distorted upward. A negative (-) voltage is applied.

  FIG. 6 is a diagram illustrating a state of the white member 103 during the reading operation. In this state, a positive (+) voltage is applied between the shim material 516 and the piezoelectric ceramic 503 via the first electrode 517 and the second electrode 518.

  Next, a document conveying operation of the image reading apparatus having the above configuration will be described. First, normal operation will be described. FIG. 7 and FIG. 8 are flowcharts showing the document transport operation procedure in the normal operation. This processing program is stored in the ROM 110 and executed by the CPU 109.

  After the power is turned on, the image reading apparatus shifts to a standby state (step S1). During standby, the image reading apparatus has the shim material 516 upward, that is, the piezoelectric ceramic 503 upward, between the shim material 516 and the piezoelectric ceramic 503 via the first electrode 517 and the second electrode 518. A negative (−) voltage is applied so as to be distorted (step S2). Thereby, as shown in FIG. 5, the shim material 516 moves in the direction away from the glass surface.

  In order to perform the reading operation, the image reading device detects whether or not there is a document on the stacking tray 1, and if there is no document, waits until the document is placed (step S3).

  When the document 101 is on the stacking tray, the image reading apparatus starts conveying the document 101 (step S4). When conveyance of the document 101 starts, the image reading apparatus alternately applies positive (+) and negative (−) voltages between the shim material 516 and the piezoelectric ceramic 503 to vibrate the shim material 516 (step S5). . The process in step S5 is an example of a control unit. As a result, the image reading apparatus reduces the adhesion force of foreign matters such as dust attached to the white member 103 and scatters the foreign matters. At the same time, the image reading apparatus vibrates the platen glass 407 that is in contact with the image reading apparatus, thereby reducing the adhesion force of the foreign matter attached to the platen glass 407 and scattering the foreign matter.

  The image reading apparatus waits until the leading edge of the document 101 passes the first reference point 519 (step S6). If the image does not pass the first reference point 519, the image reading apparatus returns to the process of step S5.

  When the leading edge of the document 101 passes the first reference point 519, the image reading apparatus stops the vibration of the white member 103 and adds (+) between the shim material 516 and the piezoelectric ceramic 503 as shown in FIG. Is applied (step S7). That is, the image reading apparatus moves (approaches) the shim material 516 in a direction approaching the platen nip portion of the document table glass 407 and presses the leading end of the document 101 against the glass surface. In this state, the document 101 is conveyed while closely contacting the document table glass 407. As a result, the image reading apparatus moves the foreign matter scattered earlier in the document transport direction at the leading end of the document 101 and reliably scrapes it out.

  The image reading apparatus waits until the trailing edge of the document 101 passes the second reference point 520 (step S8). If the second reference point 520 has not been passed, the image reading apparatus returns to the process of step S7.

  On the other hand, when the second reference point 520 is passed, the image reading apparatus has returned to the plus (+) and minus (-) between the shim material 516 and the piezoelectric ceramic 503 again because the document 101 has come out of the platen nip portion. A voltage is applied alternately (step S9). As a result, the image reading apparatus vibrates the shim material 516, reduces the adhesion force of the foreign matter attached to the white member 103, and scatters the foreign matter. At the same time, the contacting platen glass 407 is vibrated to reduce the adhesion force of foreign matter adhering to the original platen glass 407 and scatter the foreign matter.

  Then, the image reading device determines whether or not there is a next document 101 placed on the stacking tray 1 (step S10). If there is the next original 101, the image reading apparatus returns to the process of step S4 and repeats the operation for reading the next original.

  On the other hand, when there is no next original, that is, when the last page of the original passes the second reference point 520, the image reading apparatus has completed the reading operation, and therefore, a minus (between the shim material 516 and the piezoelectric ceramic 503 is provided. The voltage-) is applied (step S11). Accordingly, the image reading apparatus moves the shim material 516 in a direction away from the glass surface. Thereafter, the image reading apparatus is in a standby state (step S12), and this process ends.

  Next, the avoidance operation at the time of dust detection will be described. FIG. 9 is a flowchart showing a document transport operation procedure in the avoidance operation when dust is detected. This processing program is stored in the ROM 110 and executed by the CPU 109. In addition, since the process of step S1-S8 is the same as FIG. 7, the description is abbreviate | omitted. Moreover, the same step number is attached | subjected about the same step process as FIG.

  Description will be made from the state in which the trailing edge of the document 101 passes through the second reference point 520 in step S8, the document is removed from the platen nip portion, and the image reading operation for this page is completed. Thereafter, the image reading apparatus reads the white reference portion 521 which is the surface of the white member 103 between the pages of the document 101 (between the preceding document and the succeeding document), and whether or not foreign matter such as dust or dust exists. (Step S9A).

  If there is no foreign matter such as dust or dust, the image reading apparatus proceeds to step S10. Since the process after step S10 is the same as FIG. 8, the description is abbreviate | omitted.

  On the other hand, when the presence of foreign matter such as dust or dust is confirmed, the image reading apparatus determines the positive (+) and negative (−) voltage values or vibration frequency applied between the shim material 516 and the piezoelectric ceramic 503. Is changed (step S13). In the process of step S11, the image reading apparatus may change both the positive (+) and negative (−) voltage values (intensity) and the vibration frequency. The voltage value (intensity) and vibration frequency to be changed may be set so as to gradually change within a predetermined range, or the state of foreign matter such as dust and dust, for example, the size of the foreign matter to be read. Depending on the type or the like, a predetermined value may be set.

  Then, the image reading apparatus alternately applies positive (+) and negative (−) voltages between the shim material 516 and the piezoelectric ceramic 503 again (step S14). As a result, the image reading apparatus vibrates the shim material 516, reduces the adhesion force of the foreign matter attached to the white member 103, and scatters the foreign matter. Here, the white reference portion 521 is assumed as a reading surface to which dust adheres. However, even when dust adheres to the platen glass 407 facing the white reference portion 521, vibration is similarly applied. It is possible to scatter foreign matter.

  Thereafter, the image reading apparatus returns to the process of step S9A, reads the white reference portion 521 that is the surface of the white member 103 again, and confirms whether foreign matter such as dust or dust exists. In this way, the operation of changing the voltage or frequency is repeated until there is no foreign matter such as dust or dust. When there is no foreign matter such as dust or dust, the image reading apparatus proceeds to the process of step S10.

  The image reading apparatus determines whether or not there is a next original 101 (step S10). If there is the next original 101, the image reading apparatus returns to the process of step S4 and repeats the operation for reading the next original.

  On the other hand, when there is no next original, that is, when the last page of the original passes the second reference point 520, the image reading apparatus has completed the reading operation, and therefore, a minus (between the shim material 516 and the piezoelectric ceramic 503 is provided. The voltage-) is applied (step S11). Accordingly, the image reading apparatus moves the shim material 516 in a direction away from the glass surface. Thereafter, the image reading apparatus is in a standby state (step S12), and this process ends.

  As described above, the image reading apparatus according to the present embodiment is provided with the vibrating body on the pressure plate side (upper side) of the platen nip portion that is an actual reading surface, and directly vibrates the surface of the platen nip portion that is the reading surface. , Remove garbage. Specifically, in the image reading apparatus, a white member serving as a white reference at the time of reading provided on the pressure plate side of the platen nip portion is a vibrating body. The image reading device vibrates the white member itself placed at the reading position on the optical path, thereby directly vibrating the platen glass in contact with the white member via the platen nip portion, thereby reducing the adhesion force of dust and the like. And let the foreign matter fly off. Further, the image reading apparatus surely scrapes the scattered foreign matter at the front end of the document.

  The vibrating body has a bimorph structure in which one side of a metal shim material bent at 180 degrees is sandwiched between piezoelectric ceramic materials, and the other side is in contact with the platen glass as a white member serving as a white reference.

  Further, in order to surely scrape off the scattered foreign matter at the front end surface of the document, the white member itself, which is a shim material, is used not only as a vibrator but also as a member that performs position control and document conveyance guide. Specifically, by finely controlling so as to vary the distance between the white member and the original glass, by controlling the pressing force of the white member to the original and the approach angle of the original to the original table glass, It is possible to reliably scrape and remove the scattered foreign matter. In addition, the document can be smoothly conveyed.

  As described above, according to the image reading apparatus of the present embodiment, dust attached to the actual reading surface can be easily removed. In addition, the white reference white member itself arranged at the reading position on the optical path is vibrated, and the platen nip portion of the platen glass that is in contact is also vibrated, so that even if dust enters the reading surface, the platen nip The vibration of the part can be transmitted to foreign matter such as dust and dust. Thereby, the dust of a platen nip part can be scattered. Furthermore, it is possible to prevent foreign matter such as dust and dust from being read out by reliably scraping off the foreign matter at the leading edge of the document, and appearing as a line in the read image.

  Further, since both the white member forming the nip portion and the original platen glass are vibrated, both of these foreign matters can be removed. Further, since the vibrating body is vibrated between the original conveyed on the original platen glass and the next original, it is possible to remove foreign matters without deteriorating the reading productivity of the original.

  Further, the vibration body may be vibrated only when it is determined that there is a foreign object. In this case, the vibration body need not be unnecessarily vibrated. Further, since the white member functioning as the guide member is a vibrating body, space is saved without providing it as a separate member, and an increase in the number of parts can be suppressed.

  Further, since the shim material is used as a part of the guide member that presses the platen glass, it can be vibrated without damaging the surface of the platen glass. In addition, the organic catalyst on the platen glass can be removed or its adhesion can be reduced by the photocatalytic action.

  In addition, the photocatalytic action can be promoted by irradiation from the light source, and organic dirt can be further decomposed and removed, or the adhesion force thereof can be reduced.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above embodiment, as shown in FIG. 9, when the trailing edge of the document passes the second reference point, the image reading apparatus immediately detects the presence or absence of foreign matter such as dust and dust in step S9A. However, the operation of step S9 may be performed before that. That is, the image reading apparatus alternately applies positive (+) and negative (−) voltages between the shim material 516 and the piezoelectric ceramic 503 after the original 101 is removed from the platen nip portion in step S9. The operation of step S9A may be performed.

  In the above embodiment, the transparent member that transmits the image of the document is a single transparent member (original table glass) provided over the entire surface in the longitudinal direction (sub-scanning direction) of the image reading unit. Alternatively, a transparent member (glass) for document conveyance divided in the longitudinal direction of the image reading unit may be used.

  In the above-described embodiment, the vibrating member is provided on the white member that also serves as the guide member of the automatic document feeder. However, the present invention can also be applied to an image reading device that does not use the automatic document feeder. is there. In this case, a vibrating body is provided on a pressure plate (guide member) that holds the document against the platen glass. Further, this vibrating body may function as a white member.

  Further, the present invention can be applied as an image reading apparatus to a scanner apparatus, a facsimile apparatus having a printing function, and a multifunction peripheral (MFP) having a printing function, a copy function, a scanner function, and the like.

  In addition, the shapes of the component parts described in the above embodiment, the relative arrangement thereof, and the like should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions, and the scope of the present invention is described above. It is not limited only to what is illustrated.

  Further, the original is not particularly limited, such as a paper medium, an OHP sheet, a thick paper, a tab paper, and the like. Further, the material of the original is not particularly limited, such as a paper medium, an OHP sheet, and a cardboard paper. The shape of the document is not particularly limited, such as tab paper.

DESCRIPTION OF SYMBOLS 50 Image reading apparatus 60 Original conveying apparatus 70 Image reading part 101 Original 102 Reading device 103 White member 104 Original conveying part 405 Conveying roller 407 Original table glass 412 Reading position 413 Original size detection part 503 Piezoelectric ceramic 516 Metal shim material 521 White reference part

Claims (9)

In an image reading apparatus that reads an image of a document conveyed between a transparent member and a guide member by a document conveying unit by a reading unit via the transparent member,
An image reading apparatus comprising: vibration means for vibrating the guide member so that the guide member contacts the transparent member.   When a plurality of documents are continuously conveyed to the transparent member by the document conveying means, the guide member is moved by the vibrating means between the preceding document conveyed to the transparent member and the subsequent document being conveyed. 2. The image reading apparatus according to claim 1, further comprising control means for vibrating. Discriminating means for discriminating whether or not there is a foreign substance on the transparent member;
The image reading apparatus according to claim 1, further comprising a control unit configured to vibrate the guide member with the vibration unit when the determination unit determines that there is a foreign object.   The image reading apparatus according to claim 1, wherein the guide member is a white member serving as a white reference.   The image reading apparatus according to claim 1, wherein the guide member includes a shim material as a part of the guide member.   The image reading apparatus according to claim 1, wherein the transparent member is coated with a photocatalytic substance.   The image reading apparatus according to claim 6, wherein the photocatalytic substance is titanium oxide or a composite oxide containing titanium oxide. The reading unit includes a light source that irradiates the document, and an imaging unit that generates reflected light from the irradiated document as an image,
The image reading apparatus according to claim 6, wherein the light source includes a light source in a wavelength region that promotes a catalytic reaction of the photocatalytic substance. A document conveying device provided in an image reading apparatus having a reading unit for reading an image of a document through a transparent member, and conveying the document between the transparent member and a guide member,
An original conveying apparatus, comprising: vibration means for vibrating the guide member so that the guide member contacts the transparent member.