JP2010260692A - Image readout device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image readout device for preventing accumulation of dusts, interrupting an optical path, on an image readout section while allowing the image readout section to ensure a guide function for a document in the image readout section for thereby avoiding degradation in quality of a readout image. <P>SOLUTION: The image readout device includes: a transfer path through which the document is transferred with a thickness direction oriented in a nearly horizontal direction; and the image readout section 110 for reading out an image from the document transferred through the transfer path. The image readout section 110 has an opening portion 104a, opened to a side facing the transfer path, and a plurality of protrusions 107 located in the opening portion 104a for guiding the document transferred through the transfer path. The protrusions 107 are placed in downward slopes. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus such as a check scanner that reads an image of a document conveyed on a conveyance path in a state where a thickness direction is substantially horizontal.

  FIG. 14 shows an example of an image reading unit mounted on this type of conventional image reading apparatus. The image reading unit irradiates light to the original conveyed on the conveyance path in the sensor chassis 224, and guides light reflected from the irradiation unit 223 from the original to the line sensor 221. A rod lens array 225 is arranged.

  An opening 224a is formed on the side of the sensor chassis 224 that faces the document, and a transparent contact glass 226 is attached to the opening 224a. A substrate 222 that holds the line sensor 221 is attached to the end of the sensor chassis 224 far from the conveyance path. The rod lens array 225 has a focus position at which an image of a document conveyed on the conveyance path can be formed on the line sensor 221.

  Then, the light from the irradiation unit 223 passes through the contact glass 226 and is irradiated onto the original transported through the transport path, and the reflected light passes through the contact glass 226 and is collected by the rod lens array 225. The light condensed by the rod lens array 225 is guided to the line sensor 221 and converted into an electric signal, whereby the image of the original is read.

  Incidentally, the contact glass 226 has a function of guiding a document conveyed on the conveyance path and a function of preventing entry of dust into the sensor chassis 224. However, the contact glass 226 has a long streak on the read image due to dirt or dust adhering. The deterioration of the quality of the read image has become a problem.

  In order to solve such a problem, a technique has been proposed in which a slit and a glass plate that closes the back of the slit are provided at an image reading position of a contact glass document (Patent Document 1). In this proposal, since the conveyed document does not contact the contact glass at the image reading position, it is possible to prevent a long streak or the like due to dust from occurring in the read image.

  In addition, in an image reading apparatus that reads an image from above a horizontally placed document, a technique has been proposed in which an opening is formed at the image reading position of the document in the image reading unit without using a contact glass (Patent Document). 2). This proposal does not use contact glass that easily adheres to and accumulates dust, and prevents long streaks due to dust from occurring in the read image.

JP-A-6-326837 Japanese Patent Laid-Open No. 10-136168

  However, when the configurations of Patent Documents 1 and 2 described above are applied to an apparatus that reads an image of a document that is conveyed with the thickness direction being substantially horizontal, there are the following problems.

  That is, dust may accumulate on the glass plate that closes the slit of the contact glass, or dust may enter from the opening of the image reading unit and adhere to or accumulate on the rod lens array in the sensor chassis. For this reason, it is difficult to prevent a long streak or the like due to dust from occurring in the read image. In addition, if the opening area of the opening of the image reading unit is large, the function of guiding the transported document is lowered, so that there is a risk that the transported document will be poor and the scanned image may be distorted.

  Therefore, the present invention can prevent the dust that blocks the optical path from accumulating on the image reading unit, and avoid the deterioration of the quality of the read image by ensuring the document guide function in the image reading unit. It is an object of the present invention to provide an image reading apparatus that can be used.

  In order to achieve the above object, an image reading apparatus according to the present invention includes a conveyance path that conveys a document in a state in which the thickness direction is substantially horizontal, and an image reading that reads an image of the document conveyed through the conveyance path. The image reading unit includes an opening that opens to the side facing the conveyance path, and a plurality of documents that are disposed in the opening and guide the document conveyed through the conveyance path. And at least a part of the protrusion has an inclined shape so that the downstream side in the document transport direction is lowered.

  According to the present invention, dust that blocks the optical path can be prevented from accumulating in the image reading unit, and a document guide function in the image reading unit can be ensured, thereby avoiding deterioration in the quality of the read image. be able to.

1 is a schematic perspective view for explaining an image reading apparatus according to a first embodiment of the present invention. It is a top view of FIG. It is a detailed sectional view of an image reading unit. FIG. 6 is a perspective view of an image reading unit as viewed from a conveyance path side. It is sectional drawing of the image reading part periphery in the image reading apparatus which is the 2nd Embodiment of this invention. It is a top view for demonstrating a movable unit. It is a perspective view for demonstrating the cleaning unit. It is a perspective view for demonstrating a recessed part. It is sectional drawing for demonstrating the modification of a cleaning means. It is a perspective view for demonstrating the modification of a cleaning means. It is principal part sectional drawing of the image reading apparatus which is the 3rd Embodiment of this invention. FIG. 10 is a graph for explaining cleaning timing notification processing when there is a sufficient distance between the image reading unit and the facing surface of the image reading unit, or when the facing surface is black. FIG. 10 is a graph for explaining a cleaning timing notification process when there is no sufficient distance between the image reading unit and the facing surface of the image reading unit, or when the facing surface is other than black. It is sectional drawing which shows an example of the image reading part mounted in the conventional image reading apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic perspective view for explaining an image reading apparatus according to a first embodiment of the present invention, and FIG. 2 is a plan view of FIG.

  As shown in FIGS. 1 and 2, in the image reading apparatus 100 according to the present embodiment, a plurality of originals S are set on the paper supply unit 201 in a state where the thickness direction is substantially horizontal. A plurality of documents S are pressed against the pickup roller 205 by the pressing plate 202. In this embodiment, the document S is set up in a substantially vertical position. However, in the present invention in which the thickness direction of the document S is set in a substantially horizontal direction, the document S is set to approximately 40 ° with the vertical being 0 °. The case where it is transported within the range is also included.

  When the document S set on the sheet feeding unit 201 is detected by the document detection sensor 203, the document S is fed along the transport surface 213 by the pickup roller 205. The fed document S is separated one by one by a feed roller 206 and a retard roller 207 and fed to the conveyance path. The document fed to the conveyance path is a pair of image reading units 110 by a conveyance roller pair 208. , 120 side. In the pair of image reading units 110 and 120, the image reading unit 110 is arranged upstream of the image reading unit 120.

  A registration sensor 204 that detects the leading edge of the document S is disposed in the vicinity of the upstream side of the image reading unit 110, and a control unit (not shown) is configured based on a detection signal from the registration sensor 204. 120 image reading timing is adjusted. Then, the document S that has passed through the registration sensor 204 is scanned on the front and back images by the pair of image reading units 110 and 120, and then discharged to the paper discharge unit 212 by the paper discharge roller pair 211.

  Next, the image reading unit 110 will be described with reference to FIGS. 3 and 4. 3 is a detailed cross-sectional view of the image reading unit 110 viewed from the lower side, and FIG. 4 is a perspective view of the image reading unit 110 viewed from the conveyance path side. The image reading unit 120 is substantially the same as the image reading unit 110 except that the left and right structures are reversed.

  As shown in FIGS. 3 and 4, the image reading unit 110 includes a sensor chassis 104 having an opening 104a on the side facing the document, and the opening 104a is arranged in the width direction of the document S (upper and lower sides in FIG. 4). (Direction) of the image reading range. A guide plate 106 that guides the document S conveyed along the conveyance path is attached to the upstream side position of the opening 104a of the sensor chassis 104 along the conveyance path.

  In the sensor chassis 104, an irradiation unit 103, a rod lens array 105, and a line sensor 101 are provided.

  The rod lens array 105 extends along the width direction of the document over a range wider than the image reading range in the width direction of the document S. The rod lens array 105 is disposed so that the optical axis is substantially perpendicular to the reading surface of the document S conveyed through the conveyance path via the opening 104a. The image reading unit 110 is arranged so that the end surface closer to the conveyance path of the rod lens array 105 and the end surface far from the conveyance path are substantially parallel to the conveyance path.

  It is desirable that a sealing member 124 be disposed between the sensor chassis 104 and the rod lens array 105 to prevent dust from entering the line sensor 101 through the gap between the sensor chassis 104 and the rod lens array 105. The sealing member 124 may be an elastic member, a member combined with an elastic member, or an indeterminate member such as an adhesive material.

  The irradiation unit 103 is arranged upstream of the rod lens array 105 in the conveyance direction, and irradiates light onto the reading surface of the document S conveyed on the conveyance path through the opening 104a.

  The line sensor 101 is held by a substrate 102 attached to an end portion far from the conveyance path of the sensor chassis 104. In such a holding state, the line sensor 101 is opposed to an end surface far from the conveyance path of the rod lens array 105. It arrange | positions so that it may oppose. The rod lens array 105 has a focus position at which an image of the document S conveyed on the conveyance path can be formed on the line sensor 101.

  Then, when light is irradiated from the irradiation unit 103 onto the reading surface of the document S conveyed through the conveyance path via the opening 104a, the reflected light is condensed by the rod lens array 105 via the opening 104a. . The light condensed by the rod lens array 105 is guided to the line sensor 101 and converted into an electric signal, whereby the image of the document S is read. In the present embodiment, the pair of image reading units 110 and 120 have the same configuration except that the left and right are reversed. However, either one of the image reading units may be configured differently from the present embodiment.

  A substantially vertical wall surface 108 is provided at a position downstream of the rod lens array 105 of the sensor chassis 104 in the transport direction and gradually approaches the transport path as it becomes downstream. The upstream end of the wall surface 108 is disposed in the vicinity of the end surface closer to the conveyance path of the rod lens array 105, and the downstream end of the wall surface 108 is disposed in the vicinity of the conveyance path.

  In addition, ribs (protrusions) 107 for guiding the document S that is transported along the transport path are provided on the wall surface 108 at a predetermined interval in the width direction of the document S. As shown in FIG. 4, the plurality of ribs 107 are disposed so as to be inclined so as to approach the bottom of the apparatus toward the downstream side in the transport direction of the document S. Note that a structure in which the entire rib 107 is inclined is suitable, but a case in which at least a part is inclined is also included in the present invention. In addition, the rib 107 may be inclined so as to be closer to the bottom of the apparatus as it is farther from the wall surface 108, and this makes it difficult for dust to adhere to and accumulate on the rib 107.

  As described above, in this embodiment, since all the contact glass is removed and the opening 104a is formed at the image reading position of the document S of the image reading units 110 and 120, dust adheres to and accumulates on the contact glass. As a result, it is possible to avoid deterioration of the quality of the read image.

  Further, since the plurality of ribs 107 for guiding the conveyance of the document S are provided in the opening 104a, the document S is bent due to a conveyance failure or the like, and the reading surface of the document S is shifted from the in-focus position of the rod lens array 105. Can be prevented, and the occurrence of distortion in the read image can be avoided.

  Further, since the rib 107 provided on the inclined surface 108 is disposed so as to be lowered toward the downstream side in the conveyance direction of the document S, dust that adheres to the rib 107 can be dropped. Thereby, it is possible to prevent dust from accumulating in the openings 104a of the image reading units 110 and 120.

(Second Embodiment)
Next, an image reading apparatus according to the second embodiment of the present invention will be described with reference to FIGS. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to each figure and the description is abbreviate | omitted.

  FIG. 5 is a cross-sectional view of the periphery of the image reading unit 110, and FIG. 6 is a plan view for explaining the movable unit.

  As shown in FIGS. 5, 6, and 8, the image reading apparatus according to the present embodiment has a recess 131 formed in the installation area of the image reading units 110 and 120 on the conveyance surface 213. The image reading units 110 and 120 are arranged with the lower portions thereof inserted into the recesses 131 so that the lower ends of the sensor chassis 104 of the image reading units 110 and 120 are positioned below the conveying surface 213. The recess 131 accommodates dust that has fallen from the ribs 107 of the image reading units 110 and 120. In other words, the image reading units 110 and 120 are arranged such that the lower part protrudes below the transport surface 213.

  Further, as shown in FIG. 6, the movable unit 140 is rotatably supported in the image reading apparatus of the present embodiment so that the conveyance path can be opened. In the movable unit 140, an image reading unit 120, and roller groups 206, 208, 211 and a registration sensor 204 on the same side as the image reading unit 120 are arranged. As shown in FIGS. 6 and 7, cleaning units 132 and 133 are provided on the lower side of the movable unit 140.

  The cleaning units 132 and 133 have a cleaning member 134 such as a brush that comes into contact with the bottom surface of the recess 131. The cleaning units 132 and 133 are inserted into the recess 131 when the movable unit 140 is closed and detached from the recess 131 when the movable unit 140 is opened. To do. Thereby, the dust accumulated in the recess 131 can be scraped out and discharged to the outside.

  9 and 10 are diagrams showing modifications of the cleaning means. In this modification, an opening 141 communicating with the recess 131 is formed below the movable unit 140, and air is blown to the recess 131 by a blower 135 such as a fan installed on the opposite side of the opening 141. Thereby, the dust collected in the recess 131 can be discharged to the outside. Other configurations and operational effects are the same as those of the first embodiment.

(Third embodiment)
Next, an image reading apparatus according to the third embodiment of the present invention will be described with reference to FIGS. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to each figure and the description is abbreviate | omitted.

  In the image reading apparatus according to the present embodiment, as shown in FIG. 11, the rod lens array 105 of the image reading units 110 and 120 extends below the conveying surface 213. Although not shown, the line sensor 101 and the illumination unit 103 are also extended in accordance with the extension of the rod lens array 105, and these extended portions are used as the extension 136 of the effective reading area.

  When there is no dust in the recess 131 and the document S does not pass through, the amount of light reflected from the illumination unit 103 of the extension 136 is extremely small. Accordingly, the output from the line sensor 101 of the extension 136 is substantially the same as that when an image is read from a black document.

  When dust starts to accumulate in the recess 131, the irradiation light from the illumination unit 103 of the extension 136 is reflected by the dust, and the reflected light enters the line sensor 101 through the rod lens array 105. As a result, the output from the line sensor 101 of the extension 136 changes from a black image output to a gradually brighter image output according to the amount of accumulated dust.

  Therefore, based on the output of the line sensor 101 of the extension 136, a control unit (not shown) can monitor the dust accumulation state of the recess 131, and can notify the user of an accurate cleaning timing. It is preferable that output data from the line sensor 101 of the extension 136 is not handled as image data.

  FIG. 12 illustrates the cleaning timing notification process when there is a sufficient distance between the image reading units 110 and 120 and the opposing member facing the image reading units 110 or 120, or when the opposing member is black. FIG.

  FIG. 12A is a graph showing an example of output data from the line sensor 101 of the extension 136 when there is no dust in the recess 131. FIG. 12B is a graph illustrating an example of pixel data based on the output from the line sensor 101 of the extension 136 when dust is collected in the recess 131. 12A and 12B, the horizontal axis indicates the position of the light receiving element of the line sensor 101 of the extension 136, and the origin of the horizontal axis corresponds to the transport surface 213.

  In FIG. 12A, since there is no dust in the recess 131, the light emitted from the illumination unit 103 is not reflected, so that it hardly enters the line sensor 101 and is in the vicinity of the pixel corresponding to the extension 136 of the line sensor 101. It changes only to a slight extent. In FIG. 12B, along with the increase of dust in the recess 131, the amount of incident light on the line sensor 101 of the reflected light irradiated from the illumination unit 103 and reflected by the dust increases, and the pixel data corresponding to the extension 136 increases. You can see that

  FIG. 12C is a graph showing the relationship between the average value of the pixel data based on the output from the line sensor 101 of the extension 136 and the amount of dust accumulated in the recess 131.

  As can be seen from FIG. 12C, when there is no dust in the recess 131, the value of the pixel data based on the output from the line sensor 101 of the extension 136 is small, and the extension 136 receives the increase in dust in the recess 131. The average value of the corresponding pixel data increases.

  Here, if the possible range of pixel data is, for example, 0 to 255, the control unit (not shown) has an average value of pixel data based on the output of the extension unit 136 of the line sensor 101 as an example of a threshold value 150. When the value exceeds 128, a cleaning request is notified or the image reading operation is stopped. The notification of the cleaning request is displayed on a display unit (not shown), for example. Thereby, it is possible to prevent the image reading units 110 and 120 from reading dust that has fallen into the recess 131 from the rib 107 of the image reading units 110 and 120.

  FIG. 13 considers reflection from the facing surface or the like such that there is no sufficient distance between the image reading units 110 and 120 and the facing surface of the image reading units 110 or 120, or the facing surface is other than black. It is a graph for demonstrating the notification process of the cleaning timing in the case where it needs to do.

  FIG. 13A is a graph showing an example of pixel data based on the output from the line sensor 101 of the extension 136 when there is no dust in the recess 131. FIG. 13B is a graph showing an example of pixel data based on the output from the line sensor 101 of the extension 136 when there is dust in the recess 131. 13A and 13B, the horizontal axis indicates the position of the light receiving element of the line sensor 101 of the extension 136, and the origin of the horizontal axis corresponds to the conveyance surface 213.

  In FIG. 13A, when there is no dust in the recess 131, the light emitted from the illumination unit 103 is reflected by the opposing surface and enters the line sensor 101, and the output data from the line sensor 101 changes substantially constant. You can see that

  Here, if the intensity of the reflected light from dust is higher than the intensity of the reflected light from the facing surface, it can be easily determined. However, there is also black dust, which may be dust having a lower reflectance than the opposing surface. For this reason, in FIG. 13B, as the amount of dust increases, each pixel data corresponding to the cylindrical portion 136 varies, and there is no proportional relationship between the increase in dust and the average value of the pixel data.

  Therefore, in this example, regarding the pixel data corresponding to the extension unit 136, a difference value between adjacent pixel data is obtained, and an average value of absolute values of the difference values is used.

  FIG. 13C is a graph showing the relationship between the average absolute value of the difference values of adjacent pixel data in the portion corresponding to the extension 136 and the amount of dust accumulated in the recess 131.

  As shown in FIG. 13C, the possible range of the pixel data is, for example, 0 to 255, and the value obtained by averaging the absolute values of the difference values of adjacent pixel data exceeds, for example, 100, which is an example of the threshold value 151. In such a case, a control unit (not shown) notifies the cleaning request or stops the image reading operation. The notification of the cleaning request is displayed on a display unit (not shown), for example. Thereby, it is possible to prevent the image reading units 110 and 120 from reading dust that has fallen into the recess 131 from the rib 107 of the image reading units 110 and 120.

  In the present embodiment, the case where the rod lens array 105, the line sensor 101, and the extension unit 136 of the illumination unit 103 are provided is illustrated. However, as shown in FIG. It can be performed.

  In this case, the rod lens array 105 has an effective reading area up to a position substantially equal to the conveyance surface 213. In a state where the document S is not being transported and there is no dust on the transport surface 213, the illumination light of the illumination unit 103 is hardly reflected when the facing member is black or the like, so that the position is near the transport surface 213. Only a small amount of light is incident on the light receiving pixels of the line sensor 101. Accordingly, the pixel data based on the output of the line sensor 101 has a minute value.

  On the other hand, in a state where dust has accumulated before reaching the conveyance surface 213, the dust starts to reflect the illumination light of the illumination unit 103, so that the light receiving element of the line sensor 101 located in the vicinity of the conveyance surface 213 has a slight amount. Light enters. At this time, a change in pixel data based on the output of the line sensor 101 causes a control unit (not shown) to detect the presence of dust and display a notification of cleaning request on a display unit (not shown), or an image reading operation. To stop. Other configurations and operational effects are the same as those of the first embodiment.

  The configuration of the present invention is not limited to those exemplified in the above embodiments, and the material, shape, dimensions, form, number, arrangement location, and the like are appropriately changed without departing from the gist of the present invention. Is possible.

  For example, part or all of the processing such as calculation and determination in the present invention may be replaced with hardware processing. In addition, processing such as calculation and determination in the present invention may be executed by an external device such as a PC connected to the image reading apparatus via various interfaces, a wireless interface, an optical interface, or the like. In this case, a system including the image reading device and the external device corresponds to the image reading device of the present invention. In addition, the components of the above embodiments may be added to other embodiments and are included in the present invention.

DESCRIPTION OF SYMBOLS 100 Image reading apparatus 101 Line sensor 102 Board | substrate 103 Illumination unit 104 Sensor chassis 104a Opening part 105 Rod lens array 106 Guide plate 107 Rib 108 Inclined surface 110 Image reading part 120 Image reading part 201 Paper feeding part 202 Pressing plate 203 Original detection sensor 204 Registration sensor 205 Pickup roller 206 Feed roller 207 Retard roller 208 Conveying roller pair 211 Discharging roller pair 212 Paper discharging unit 213 Conveying surface

Claims (8)

An image reading apparatus comprising: a conveyance path that conveys a document in a state in which the thickness direction is substantially horizontal; and an image reading unit that reads an image of the document conveyed through the conveyance path.
The image reading unit includes an opening that opens to the side facing the conveyance path, and a plurality of protrusions that are disposed in the opening and guide a document that is conveyed along the conveyance path. At least a part of the shape is inclined so that the downstream side in the document transport direction is lowered.
An image reading apparatus. The opening is formed in a wider range than the image reading range in the width direction of the document.
The image reading apparatus according to claim 1. The opening has a substantially vertical wall surface that is closer to the conveyance path toward the downstream side in the document conveyance direction, and the protrusion is disposed on the wall surface.
The image reading apparatus according to claim 1, wherein The protrusion has a shape in which a tip portion thereof is closer to the conveyance path toward a portion downstream of the document conveyance direction.
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. A recess is formed in the installation area of the image reading unit on the document conveyance surface to accommodate dust dropped from the projection, and a lower end of the image reading unit protrudes downward from the conveyance surface and is disposed in the recess. ,
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The image reading apparatus according to claim 5, further comprising a cleaning unit that cleans dust accumulated in the recess. 7. The image according to claim 5, further comprising a monitoring unit that monitors a dust accumulation state of the concave portion based on pixel data read in the vicinity of the conveyance surface using the image reading unit. Reader. The effective reading area of the image reading unit extends below the conveyance surface, and the accumulation state of dust in the concave portion is determined based on pixel data read in the reading area below the conveyance surface of the image reading unit. The image reading apparatus according to claim 5, further comprising monitoring means for monitoring.