JP4946699B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an image of a document placed on a transparent plate member.

  In an image reading apparatus including a flatbed scanner, an image of an original is read by the image sensor in a process in which the image sensor is moved in a predetermined direction with respect to the original placed on the contact glass. The document is read by the image sensor through the contact glass while being pressed against the contact glass by the document pressing member. For this reason, when the colors of the document and the document pressing member are similar, the edge of the document may not be detected accurately. For this reason, the conventional image reading apparatus is provided with means for detecting the edge of the document (for example, see Patent Document 1).

  The image reading apparatus described in Patent Document 1 is provided with a document cover that covers the contact glass and is rotatable with respect to the contact glass. A document pressing member is provided on the back side of the document cover. A reference member for positioning the edge of the document is provided on the upper surface of the contact glass. The document is placed on the contact glass so that the edge of the document contacts the reference member. The document on the contact glass is pressed against the document pressing member and is brought into close contact with the contact glass. The image of the document placed on the contact glass is read through the contact glass by the line sensor in the process of moving the line sensor in a predetermined direction. In this image reading apparatus, in addition to the document area, an image outside the document area is read by the line sensor. By performing predetermined arithmetic processing on the read image data, a plurality of pixels indicating the edge of the document are detected. A straight line connecting these pixels is determined as each side of the original, and the inclination of the original and the position of the corner of the original are obtained based on a linear expression representing each of the sides.

Japanese Patent Laid-Open No. 11-252351

  FIG. 10 is a schematic diagram schematically showing image data 148 which is an example of an image read by a conventional image reading apparatus. In FIG. 10, reference numeral 145 indicated by a two-dot chain line is a reference member for positioning the end of the document. Similarly, 146 indicated by a two-dot chain line indicates an end side (edge line) of the document pressing member arranged in parallel to a position adjacent to the reference member 145 when the document cover is closed with respect to the contact glass. A region indicated by a solid line so that an edge 149 of the document indicated by a two-dot chain line intersects the edge line 146 of the document pressing is the image data 148. For convenience of explanation, FIG. 10 shows a state in which the edge line 146 is extremely far from the reference member 145 and the edge 149 is extremely inclined with respect to the edge line 146. . Hereinafter, with reference to FIG. 10, a problem when the image reading is performed in a state where the document is inclined with respect to the reference member 145 will be described. In the conventional image reading apparatus, when the image reading is performed in a state where the edge 149 intersects the edge line 146, the edge 149 and the edge line 146 cannot be clearly distinguished. For this reason, the position and inclination of the end side 149 cannot be accurately determined. As a result, as indicated by the image data 148, there is a problem that an area between the edge 149 and the edge line 146 of the document is erroneously read as an image of the document. Such a problem occurs when the image is read with the edge 149 and the edge line 146 overlapped due to the displacement of the document due to wind pressure or the like by the document cover.

  The present invention has been made in view of such a problem, and can accurately determine the position and inclination of the edge of the document without erroneously determining the edge of the document pressing member as the edge of the document. An object is to provide a reader.

(1) An image reading apparatus according to the present invention is provided with a transparent plate-like member on which an outer edge is supported by a support frame, on which a document is placed, and disposed on the back side of the plate-like member. A reading unit that starts image reading from the first end toward the second end opposite to the first end, and a hinge connected to the apparatus, opens and closes the plate-like member, and is closed. A pressing member that covers the upper surface of the plate-like member and presses the document placed on the plate-like member in a state where the plate-like member is placed, and a first support portion of the support frame that corresponds to the first end. A plurality of projecting portions projecting from one support portion toward the plate-like member, and the first end side of the document placed on the plate-like member is in contact with the first end; The first end and the second end are formed by straight lines whose end sides are determined by end portions of the plurality of protruding portions on the plate-like member side A positioning member that is positioned at a reference position between the first position and the plate-like member, the first end side of the reference position and the first position that is surrounded by the reference position and the support frame Placed in the second region based on at least one continuous part that makes the region and the second region from the reference position to the second end continuous, and image data of the continuous part read by the reading unit And a determination unit for determining an end side of the original on the first end side.

  A positioning member is provided on the upper surface of the plate-like member. The document placed in the second area is positioned at a reference position between the first end and the second end, with the edge on the first end side being in contact with the positioning member. Here, the region from the first end to the reference position is referred to as a first region, and the second region from the reference position to the second end is referred to as a first region. The document placed in the second area is restricted from moving toward the first area by the positioning member. The plate-like member is provided with a continuous portion. In the first region and the second region, the region not covered with the positioning member is continuous through this continuous portion. When image reading by the reading unit is started, image data of the continuous portion is acquired together with image data of the first region and image data of the second region. In the image data of this continuous portion, the edge of the document placed in the second region appears without showing the edge of the pressing member that may be determined to be the edge of the document. Therefore, the determination unit accurately determines the position and inclination of the edge of the document without erroneously determining the edge of the pressing member as the edge of the document.

  When the document placed in the second area is brought into contact with the positioning member, the end side on the first end side is positioned. When the pressing member is closed with respect to the plate-like member, the document may be displaced due to wind pressure or the like by the pressing member. The determination unit determines the position and inclination of the edge of the document even when the document is displaced as described above. Therefore, the present invention can be preferably applied to an apparatus having a member for positioning an edge of a document.

(2) The positioning member is configured such that the positioning member has an end side on the third end side that intersects the first end of the plate-like member among the end sides of the document placed on the plate-like member. The end side on the third end side is brought into contact with the second reference position on the plate-like member formed by a straight line determined by the third support portion which is the end portion on the third end side of the support frame. Positioning is performed, and one of the continuous portions may include an intersection of a virtual straight line along the reference position and a virtual straight line along the second reference position.

  In an apparatus in which the reading unit has a function of setting a reading range of a document on the basis of the third end side in addition to the first end side of the plate-like member, one of the continuous portions is a virtual along the reference position. If the intersection of the straight line and the virtual straight line along the second reference position is included, the position and inclination of the document can be determined more accurately.

(3) One of the continuous portions may be provided at a position corresponding to the center position of the first end in the positioning member.

  In the apparatus in which the reading unit has a function of setting the reading range of the document with reference to the center position of the positioning member, one of the continuous portions is provided at a position corresponding to the center position of the first end of the plate member. If so, the position and inclination of the document can be determined more reliably.

  (4) It is preferable that the plurality of continuous portions are arranged along the first end.

  With the above configuration, the edge on the first end side of the document is determined based on the image data of the plurality of continuous portions. For this reason, the position and inclination of the edge on the first end side can be determined more accurately.

The continuous portion includes a first gap between one of the plurality of protrusions adjacent to the support frame and the support frame, and a second gap between the adjacent sets of the plurality of protrusions. In addition to the second region, the pressing member may cover the first gap and the second gap.

  The first region and the second region in the plate-like member are covered with the pressing member. For this reason, the edge on the first end side of the document arranged in the continuous portion is pressed by the pressing member and is in close contact with the plate member. The edge on the first end side of the document is prevented from floating from the plate-like member, and the edge is accurately determined.

  According to the present invention, the edge of the document is accurately determined without erroneously determining the edge of the pressing member as the edge of the document.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only an example of this invention and can be suitably changed in the range which does not change the summary of this invention.

  First, the configuration and operation of the multifunction machine 10 according to an embodiment of the image reading apparatus of the present invention will be described.

<Schematic configuration of MFP 10>
FIG. 1 is a perspective view showing an external configuration of a multifunction machine 10 which is an example of an image reading apparatus of the present invention. FIG. 2 is a plan view showing the internal configuration of the document table 19. FIG. 2 shows a state where the upper surface support frame 22 (see FIG. 1) is removed.

  The multifunction machine 10 is a multi-function device (MFD: Multi Function Device) that integrally includes a scanner unit 11 and a printer unit 12, and has various functions such as a scan function, a print function, a copy function, and a facsimile function. The present invention can be applied not only to the multifunction machine 10 having a plurality of functions but also to an image reading apparatus having at least a scan function.

  As shown in FIG. 1, the multifunction machine 10 has a wide and thin, generally rectangular parallelepiped outer shape having a width and depth larger than the height. The upper part of the multifunction machine 10 is a scanner unit 11. As shown in FIG. 1, the scanner unit 11 is configured such that a document cover 15 can be opened and closed with respect to a document table 19 via a hinge 17 on the back side. The document table 19 functions as a flat bed scanner. The document cover 15 functions as a top plate of the multifunction machine 10. The document table 19 has a contact glass 20 (an example of the plate member of the present invention) on which a document is placed. An original of A4 size or legal size or smaller is placed on the contact glass 20 so that the reading surface faces downward. On the back side of the contact glass 20, an image reading unit 24 (an example of the reading unit of the present invention, see FIG. 2), which will be described later, is arranged. The image reading unit 24 reads an image of a document placed on the contact glass 20. In FIG. 1, the four end sides of the contact glass 20 are indicated by broken lines because they are covered with the upper surface support frame 22 (an example of the support frame of the present invention).

  The contact glass 20 is made of a single transparent glass plate or acrylic plate. As shown in FIGS. 1 and 2, the document table 19 includes a substantially rectangular parallelepiped casing 21 and an upper surface support frame 22 having an opening formed on the upper surface. The contact glass 20 is sufficiently larger than the opening of the upper support frame 22 (see FIG. 1). The document table 19 is configured such that a top support frame 22 is fitted from above onto a casing 21 that supports the contact glass 20 from below. A lower surface support frame 23 is provided inside the housing 21 (see FIG. 2). The lower surface support frame 23 is provided at a position corresponding to the first end 41, the second end 42, the third end 43, and the fourth end 44 which are the end portions of the contact glass 20 shown in FIG. 1. By placing the contact glass 20 on the lower surface support frame 23, the first end 41, the second end 42, the third end 43, and the fourth end 44 are supported from below by the lower surface support frame 23. An upper surface support frame 22 is fitted into the housing 21 from above. Thereby, the first end 41, the second end 42, the third end 43, and the fourth end 44 of the contact glass 20 are sandwiched between the lower surface support frame 23 and the upper surface support frame 22. That is, the upper surface support frame 22 supports the end portion of the contact glass 20 together with the lower surface support frame 23.

  As shown in FIG. 1, a pressing member 16 (an example of the pressing member of the present invention) is provided on the back surface of the document cover 15 facing the contact glass 20. The pressing member 16 is made of, for example, a plate-like sponge. However, the pressing member 16 is not limited to this, and may be configured of a member having elasticity such as rubber. In this embodiment, the pressing member 16 is formed so as to cover the exposed surface of the contact glass 20 on the upper surface of the document table 19. Further, the pressing member 16 is formed to be slightly smaller than the exposed surface so as not to run over the upper support frame 22 (see FIG. 4). When the document cover 15 is closed, the pressing member 16 covers the upper surface of the contact glass 20 and presses the document on the contact glass 20. Note that the pressing member 16 has a single white color over the entire area so that the line sensor 25 obtains stable reflected light from the original and obtains the same output as white for an area where no original exists.

  The lower part of the multifunction machine 10 is a printer unit 12. The printer unit 12 records an image on a recording sheet based on image data of a document read by the scanner unit 11 or print data input from the outside. In realizing the present invention, the printer unit 12 has an arbitrary configuration, and a detailed description thereof is omitted here.

  An operation panel 14 is provided in the upper front portion of the multifunction machine 10. The operation panel 14 includes a liquid crystal display for displaying various information, an input key for the user to input information, and the like. The scanner unit 11 and the printer unit 12 operate based on an instruction signal input from the operation panel 14 or an instruction signal transmitted from an external device using a printer driver or a scanner driver.

<Configuration of Scanner Unit 11>
Hereinafter, the configuration of the scanner unit 11 will be described with reference to FIG. As shown in FIG. 2, an image reading unit 24 is provided inside the casing 21 of the document table 19. The image reading unit 24 reads an image through the contact glass 20. The image reading unit 24 includes a line sensor 25, a carriage 26, a guide shaft 27, and a belt driving mechanism 28.

  The line sensor 25 irradiates the reading area (exposed surface) on the contact glass 20 and reads the reflected light. As the line sensor 25, a reading device having a short focal length, for example, a contact image sensor (CIS) is used. Although not shown, the line sensor 25 includes a light source, a lens, and a light receiving element. The light receiving elements of the line sensor 25 are arranged side by side so as to include the exposed surface of the contact glass 20 in the main scanning direction (direction indicated by the arrow 39) of the document in units of chips, for example. The light source and lens of the line sensor 25 are arranged in the same direction as the light receiving element. The line sensor 25 irradiates light from the light source toward the contact glass 20. The line sensor 25 condenses the reflected light of the irradiated light by a lens and converts it into an electrical signal (image signal) by a light receiving element.

  As shown in FIG. 2, the carriage 26 has a line sensor 25 mounted on the upper side thereof. Inside the housing 21, a guide shaft 27 is provided in the document sub-scanning direction (direction indicated by an arrow 38). The carriage 26 is fitted with the guide shaft 27. The carriage 26 is driven by the belt driving mechanism 28 and moves on the guide shaft 27 in the sub-scanning direction. The carriage 26 moves in the sub-scanning direction so that at least the exposed surface on the contact glass 20 is included in the movement range of the carriage 26. Since the line sensor 25 is mounted on the carriage 26, the line sensor 25 is moved in the sub-scanning direction together with the carriage 26.

  As shown in FIG. 2, the belt driving mechanism 28 includes a driving belt 31, a driving pulley 29, and a driven pulley 30. The driving pulley 29 and the driven pulley 30 are respectively provided at both ends in the width direction of the housing 21 (left and right direction in FIG. 2). The drive belt 31 is an endless ring having teeth on the inside. The drive belt 31 is stretched between the drive pulley 29 and the driven pulley 30. A driving force from the motor 35 (see FIG. 5) is transmitted to the shaft of the driving pulley 29. The drive belt 31 moves circumferentially by the rotation of the drive pulley 29. As a result, the carriage 26 is moved in the sub-scanning direction so as to face the reading area of the contact glass 20. As the motor 35, for example, a stepping motor is used. The position of the carriage 26, that is, the line sensor 25 in the sub-scanning direction is monitored by counting the number of steps of the motor 35.

<Positioning member 70>
FIG. 3 is an enlarged view of a portion III in FIG.

  As shown in FIG. 1, a positioning member 70 (an example of the positioning member of the present invention) is disposed on the upper surface of the contact glass 20. As shown in FIG. 3, the positioning member 70 is disposed at a reference position 47 (an example of the reference position of the present invention) on the contact glass 20. The positioning member 70 is integrally formed with the upper surface support frame 22 in this embodiment. Here, the reference position 47 is a position separated from the first end 41 (see FIGS. 1 and 3) of the contact glass 20 to the second end 42 (see FIG. 1). The reference position 47 is a position that serves as a reference for positioning the edge on the first end 41 side of the document placed on the contact glass 20. That is, as shown in FIG. 3, the positioning member 70 is provided on the first support portion 45 in the upper surface support frame 22 corresponding to the first end 41. The positioning member 70 is integrally formed with the upper surface support frame 22 in the present embodiment, but may be formed of a member separate from the upper surface support frame 22.

  As shown in FIGS. 1 and 3, the positioning member 70 is a plate-like member that is long in the depth direction of the document table 19, in other words, in the extending direction of the line sensor 25 (see FIG. 2). The positioning member 70 has four projecting portions 51, 52, 53, 54 that project from the first support portion 45 to the plate-shaped member 20 side. The protruding portions 51, 52, 53, 54 are extended from the first support portion 45 so that their tips substantially coincide with the reference position 47. That is, the reference position 47 is a position determined by the tips of the protrusions 51, 52, 53, 54.

  As shown in FIG. 3, first regions 71, 72, 73 and 74 are formed on the upper surface of the contact glass 20 on the first end 41 side with respect to the reference position 47. The first regions 71, 72, 73, 74 are closer to the first end 41 than the reference position 47, and the contact glass 20 is connected to the third support portion 46 and the first support portion 45 in the upper surface support frame 22. , And the areas not covered by the protrusions 51, 52, 53, 54.

  In the support frame 22, a second support portion 57 is provided at a position facing the first support portion 45. The second support part 57 covers the second end 42 of the contact glass 20. The tip of the protrusions 51, 52, 53, 54, that is, the area from the reference position 47 to the second support part 57 is the second area 76. The second area 76 is an area where a document can be placed. Thus, the upper surface of the contact glass 20 is distinguished into the first regions 71, 72, 73, 74 and the second region 76 with the reference position 47 as a boundary.

  As shown in FIG. 3, the first regions 71, 72, 73, 74 are open to the second end 42 (see FIG. 1) side. The second area 76 is continuous with the first areas 71, 72, 73, 74. Hereinafter, each continuous region between the first region 71, 72, 73, 74 and the second region 76 is referred to as a continuous part 81, 82, 83, 84 (an example of a continuous part of the present invention). The continuous part 81 is to make the first region 71 and the second region 76 continuous. The continuous part 82 makes the first region 72 and the second region 76 continuous. The continuous part 83 makes the first region 73 and the second region 76 continuous. The continuous part 84 makes the first region 74 and the second region 76 continuous. In addition, the clearance gap between the protrusion part 51 in which the 1st area | region 71 was formed, and the 3rd support part 46 is equivalent to the 1st clearance gap of this invention. Further, between the protrusion 51 and the protrusion 52 where the first region 72 is formed, between the protrusion 52 and the protrusion 53 where the first region 73 is formed, and the protrusion where the first region 74 is formed. The space between the portion 53 and the protruding portion 54 corresponds to the second gap of the present invention.

  The positioning member 70 is used as a document positioning reference when the user places the document in the second region 76. The document is placed on the second region 76 with the indication on the positioning member 70 as a mark. Although not shown in the drawing, the positioning member 70 has a display indicating the end positions of various documents such as A4 size and B5 size. Using this notation as a mark, the document is placed in the second area 76. In the document 50 (see FIG. 4) placed in the second region 76, the end side 49 (see FIG. 4) on the first end 41 side is brought into contact with the tips of the projecting portions 51, 52, 53, 54. As a result, the side 50 (see FIG. 4) on the first end 41 side of the original 50 is positioned at the reference position 47, and entry of the original 50 into the first areas 71, 72, 73, 74 is restricted. The As a result, the edge 50 of the document 50 is arranged at the continuous portions 81, 82, 83, 84.

  Since the positioning member 70 is disposed on the contact glass 20, the first regions 71, 72, 73, 74, the continuous portions 81, 82, 83, 84, and the second region 76 are opened from the opening of the upper surface support frame 22. Exposed upward.

<Presser member 16>
FIG. 4 is a plan view schematically showing the document table 19. 4 shows a state in which the end side 49 of the document 50 placed in the second region 76 is separated from the positioning member 70 and is inclined with respect to the reference position 47. In FIG. 4, the pressing member 16 in a state where the document cover 15 (see FIG. 1) is closed is indicated by a broken line.

  As shown in FIGS. 1 and 4, the pressing member 16 includes four first pressing portions 61, 62, 63, 64 and a second pressing portion 66 (see FIG. 1). . The first pressing parts 61, 62, 63, 64 are provided so as to protrude from the second pressing part 66 to the first end 41 side. The second pressing portion 66 is provided at a position corresponding to the second region 76 on the contact glass 20 on the back surface of the document cover 15. As shown in FIG. 4, the second pressing portion 66 is formed in substantially the same shape as the second region 76 in plan view. The second pressing portion 66 is formed slightly smaller than the second region 76 so that the second pressing portion 66 does not run on the upper surface support frame 22 when the document cover 15 is closed. For this reason, when the document cover 15 is closed, the second pressing portion 66 comes into close contact with the upper surface of the document 50 or the contact glass 20 in the second region 76.

  As shown in FIGS. 1 and 4, the first pressing portion 61 is provided at a position corresponding to the first region 71 on the back surface of the document cover 15. The first pressing portion 62 is provided at a position corresponding to the first region 72 on the back surface of the document cover 15. The first pressing portion 63 is provided at a position corresponding to the first region 73 on the back surface of the document cover 15. The first pressing portion 64 is provided at a position corresponding to the first region 74 on the back surface of the document cover 15.

  As shown in FIG. 4, the first pressing portion 61 is formed in substantially the same shape as the first region 71 in plan view. The first pressing portion 61 is formed slightly smaller than the first region 71 so as to be in close contact with the upper surface of the contact glass 20 in the first region 71 when the document cover 15 is closed. Further, the first pressing portion 62 is formed in substantially the same shape as the first region 72 in plan view. The first pressing portion 62 is formed slightly smaller than the first region 72 so as to be in close contact with the upper surface of the contact glass 20 in the first region 72 when the document cover 15 is closed. Further, the first pressing portion 63 is formed in substantially the same shape as the first region 73 in plan view. The first pressing portion 63 is formed slightly smaller than the first region 73 so as to be in close contact with the upper surface of the contact glass 20 in the first region 73 when the document cover 15 is closed. The first pressing portion 64 is formed in substantially the same shape as the first region 74 in plan view. The first pressing portion 64 is formed slightly smaller than the first region 74 so as to be in close contact with the upper surface of the contact glass 20 in the first region 74 when the document cover 15 is closed.

  The document cover 15 is closed with respect to the document table 19. Accordingly, the second region 76 is covered with the second pressing portion 66, the first region 71 is covered with the first pressing portion 61, the first region 72 is covered with the first pressing portion 62, and the first region 73 is Covered by the first pressing part 63, the first region 74 is covered by the first pressing part 64. That is, in addition to the second region 76, between the upper surface support frame 22 and the protrusion 51, between the two adjacent protrusions 51 and 52, and between the two adjacent protrusions 52 and 53. In the meantime, the space between the two adjacent protrusions 53 and 54 is covered by the pressing member 16.

  The document 50 placed in the second region 76 is pressed toward the contact glass 20 by the second pressing portion 66. As a result, the reading surface of the document 50 is in close contact with the upper surface of the contact glass 20 in the second region 76. The pressing member 16 is provided so that the first pressing portions 61, 62, 63, 64 protrude from the reference position 47 toward the first end 41. For this reason, the end side on the first end 41 side of the pressing member 16 is not arranged in the continuous portions 81, 82, 83, 84. In other words, the continuous portions 81, 82, 83, 84 provided at the reference position 47 (see FIG. 4) do not have an end portion on the first end 41 side of the pressing member 16, and only the end side of the document 50. (Refer to FIG. 3 and FIG. 4).

  For example, when an instruction to start printing is given from the operation panel 14, the image reading unit 24 starts image reading from the first end 41 toward the second end 42. Specifically, the carriage 26 is moved from the first end 41 to the second end 42 of the contact glass 20 (from the left side to the right side in FIG. 2). Thereby, the line sensor 25 is moved along the first regions 71, 72, 73, 74 facing the contact glass 20, and subsequently moved along the continuous portions 81, 82, 83, 84. Are moved along the second region 76. In this moving process, the image reading for each main scanning line by the line sensor 25 is repeated, and the image data of the reading area is acquired. This image data includes image data of the first area 71, 72, 73, 74 and image data of the second area 76.

<Control unit 100>
Next, a schematic configuration of the control unit 100 will be described with reference to FIG. FIG. 5 is a block diagram illustrating a schematic configuration of the control unit 100.

The control unit 100 controls the overall operation of the multifunction machine 10 in an integrated manner. As shown in FIG. 5, the control unit 100 is configured as a microcomputer mainly including a CPU 101, a ROM 102, a RAM 103, an EEPROM 104, and an ASIC (Application Specific Integrated Circuit) 105. This control unit 100 functions as a determination unit of the present invention. The control unit 100 controls the image reading unit 24, each driving device of the printer unit 12, and the like.

  The ROM 102 stores a program for the CPU 101 to control the image reading unit 24 and the multifunction peripheral 10. The ROM 102 stores position information of the first areas 71, 72, 73, 74, the second area 76, and the continuous portions 81, 82, 83, 84 in the reading area on the contact glass 20. Based on these pieces of position information, the control unit 100 can determine to which area the pixel data constituting the image data obtained by the image reading unit 24 corresponds. The RAM 103 is used as a storage area for temporarily storing various data used when the CPU 101 executes the program, or as a work area for data processing. The EEPROM 104 stores settings, flags, and the like that should be retained even after the power is turned off.

  Connected to the ASIC 105 are an image reading unit 24, an AFE (Analog Front End) circuit 36, and an image processing circuit 37. Although not shown in FIG. 5, the ASIC 105 is also connected to the printer unit 12, the operation panel 14, and the like. Since the control of these other devices is not related to the present invention, the description thereof is omitted here.

  The image reading unit 24 includes a drive circuit 33, a motor 35, and a line sensor 25. The drive circuit 33 energizes the motor 35 with a drive signal based on a phase excitation signal or the like input from the ASIC. In response to this drive signal, the motor 35 is driven to rotate, and the carriage 26 is moved in the sub-scanning direction. The drive circuit 33 controls image reading by the line sensor 24. The images of the first areas 71, 72, 73, 74 and the second area 76 read by the line sensor 25 during the movement of the carriage 26 are output from the line sensor 25 to the AFE circuit 36 as image signals (image data). The In the present embodiment, the scanner unit 11 has a function in which the image reading unit 24 sets a reading range of the document 50 with reference to the third end 43 (see FIG. 1) of the contact glass 20.

  The AFE circuit 36 converts the analog image signal output from the line sensor 25 into a digital signal composed of a digital code having a predetermined number of bits. This digital conversion is performed by an analog / digital converter. The AFE circuit 36 also performs gain adjustment for amplifying the input image signal. The analog image signal input to the AFE circuit 36 is output to the image processing circuit 37 as, for example, a digital image signal of 8 bits (256 gradations: 0 to 255). The image processing circuit 37 performs image processing such as shading correction, γ correction, color space conversion, and binarization as necessary. The image data processed by the image processing circuit 37 is input to the control unit 100.

<End Edge 49 Detection Process>
When image reading by the image reading unit 24 is performed, image data of a reading region including the first regions 71, 72, 73, 74 and the second region 76 is acquired. The image data is processed by the AFE circuit 36 and the image processing circuit 37 and then input to the control unit 100. The control unit 100 determines the image data of the continuous units 81, 82, 83, 84 from the image data input from the image processing circuit 37. This discrimination processing is performed by comparing the position information of the continuous portions 81, 82, 83, 84 stored in the ROM 102 with the position information of each pixel data constituting the image data input from the image processing circuit 37. Done. The control unit 100 detects a plurality of pixels indicating the edge of the document by performing predetermined arithmetic processing on the image data of the continuous portions 81, 82, 83, and 84 determined in this way. This process is performed for each of the continuous part 81, the continuous part 82, the continuous part 83, and the continuous part 84. Then, the control unit 100 determines that the straight line connecting these pixels is the edge 49 of the document 50. The control unit 100 determines the inclination of the document 50 and the position of the corner of the document 50 based on the linear expression representing the end side 49. As described above, the control unit 100 determines the edge 49 of the document 50 based on the image data of the continuous units 81, 82, 83, and 84. Note that the processing for determining the inclination and corner position of the document 50 by obtaining a straight line formula is the method disclosed in paragraphs [0036] to [0040] of Japanese Patent Application Laid-Open No. 11-252351, that is, a plurality of edges. Since it can be performed by acquiring points, deleting unnecessary edge points by template matching, and detecting the coordinates of straight lines by linear regression, a detailed description thereof is omitted here.

FIG. 6 is an enlarged view of a VI portion in FIG. FIG. 7 is an enlarged view of a portion VII in FIG.

<Operational effects of this embodiment>
As apparent from the continuous portion 81 shown in FIG. 6 and the continuous portion 83 shown in FIG. 7, the image data of the continuous portions 81, 82, 83, 84 is determined to be the edge of the original 50. The end side 49 of the document 50 placed in the second region 76 appears without showing the end side of the pressing member 16 that may be feared. Therefore, the control unit 100 can accurately determine the position and inclination of the edge 49 of the document 50 without erroneously determining the edge of the pressing member 16 as the edge 49 of the document 50.

  When the document 50 placed in the second region 76 is brought into contact with the positioning member 70, the end side 49 of the document 50 is positioned at the reference position 47 (see FIG. 3). When the document cover 15 is closed with respect to the contact glass 20, the document 50 may be displaced due to wind pressure or the like by the document cover 15 or the pressing member 16. The control unit 100 can determine the position and inclination of the edge 49 of the document 50 based on the image data of the continuous portions 81, 82, 83, and 84 even when the document 50 is displaced as described above.

  In the scanner unit 11 according to the present embodiment, the image reading unit 24 sets the reading range of the document 50 with reference to the third end 43 (see FIG. 1) of the contact glass 20. In other words, the document 50 is arranged so that the corners thereof are positioned at the continuous portion 81 (see FIG. 6) regardless of the document size. Therefore, the position and inclination of the document 50 can be accurately determined based on the image data of the continuous portion 81 regardless of the document size.

  The pressing member of the present invention may be formed so as to cover the entire upper surface of the document table 19 including the positioning member 70. However, as in the present embodiment, the pressing member 16 is formed so as to cover only the first regions 71, 72, 73, 74 and the second region 76, thereby being arranged in the continuous portions 81, 82, 83, 84. The edge 49 of the prepared document 50 is in close contact with the contact glass 20. As a result, the end side 49 is prevented from floating from the contact glass 20, and the end side 49 is accurately determined. Therefore, it is preferable to form the pressing member 16 so as to cover only the first regions 71, 72, 73, 74 and the second region 76 as in the present embodiment.

  Further, in the present embodiment, the description has been given of the form in which the positioning member 70 is provided with four (a plurality of examples) continuous portions 81, 82, 83, 84, but one continuous portion may be provided. . However, by determining the end side 49 based on the image data of a plurality of continuous portions, the position and inclination of the end side 49 can be compared with the case of determining the end side 49 based on the image data of one continuous portion. More accurate determination can be made. For this reason, it is preferable that a plurality of continuous portions of the present invention are provided on the positioning member 70.

  FIG. 8 is a schematic diagram showing a part of the document table 19 in which the continuous portion 114 is provided on the third support portion 46.

  As shown in FIG. 8, the continuous portion 114 is provided in a region where the contact glass 20 is not covered with the third support portion 46 (see FIG. 1) in the upper surface support frame 22 corresponding to the third end 43. Also good. In this case, as shown in FIG. 8, two protruding portions 110 and protruding portions 111 adjacent to the third end 43 of the upper surface support frame 22 are provided. A continuous portion 114 is formed between the protruding portion 110 and the protruding portion 111. The pressing member 16 (see FIG. 1) is provided with a first pressing portion 116 at a position corresponding to the continuous portion 114. In addition, the line along the front-end | tip of the protrusion part 110 and the protrusion part 111 is equivalent to the 2nd reference position of this invention.

  By configuring the upper surface support frame 22 and the pressing member 16 in this way, it is possible to determine the edge 48 of the document 50. Based on the determination result of the end side 49 and the end side 48, the position and inclination of the document 50 can be determined more accurately.

  FIG. 9 is a schematic diagram showing a positioning member 140 (an example of a positioning member of the present invention) provided with continuous parts 141, 142, and 143 (an example of a continuous part of the present invention). In FIG. 9, the pressing member 124 in a state where the document cover 15 (see FIG. 1) is closed is indicated by a broken line. The pressing member 124 includes three first pressing portions 131, 132, 133 and a second pressing portion 66 (see FIG. 1).

  As shown in FIG. 9, the continuous portion 142 may be provided at a location corresponding to the center position of the first end 41 in the positioning member 140. The positioning member 140 is provided with a protruding portion 125, a protruding portion 126, a protruding portion 127, and a protruding portion 128 from the third end 43 side along the first end 41. A first region 121 is formed between the protruding portion 125 and the protruding portion 126, a first region 122 is formed between the protruding portion 126 and the protruding portion 127, and the first region 122 is formed between the protruding portion 127 and the protruding portion 128. One region 123 is formed. A continuous portion 141 is configured by the tips of two adjacent protrusions 125 and 126 at the reference position 47. Further, a continuous portion 142 is configured by the tips of two adjacent protruding portions 126 and protruding portions 127 at the reference position 47. In addition, a continuous portion 143 is configured by the tips of two adjacent protruding portions 127 and protruding portions 128 at the reference position 47. The positioning member 140 is configured in the same manner as the positioning member 70 except that the position where the protruding portion and the continuous portion are formed in the present invention is different.

  In this case, in the scanner unit 11, the reading range of the document is set by the image reading unit 24 with reference to the center position of the first end 41 of the contact glass 20. The document is placed on the second region 76 on the contact glass 20 so that the center position in the width direction is located at the continuous portion 142 regardless of the document size. Based on the image data of the continuous portions 141, 142, and 143, the position and inclination of the edge 49 of the document 50 are accurately determined.

  Note that the document is placed on the second region 76 on the contact glass 20 so that the center position in the width direction is located at the continuous portion 142 regardless of the document size, so that the three continuous portions 141, 142, and 143 Of these, only the continuous portion 142 may be formed in a region not covered with the positioning member 140.

FIG. 1 is a perspective view showing an external configuration of a multifunction machine 10 which is an example of an image reading apparatus of the present invention. FIG. 2 is a plan view showing the internal configuration of the document table 19. FIG. 3 is an enlarged view of a portion III in FIG. FIG. 4 is a plan view schematically showing the document table 19. FIG. 5 is a block diagram illustrating a schematic configuration of the control unit 100. FIG. 6 is an enlarged view of a VI portion in FIG. FIG. 7 is an enlarged view of a portion VII in FIG. FIG. 8 is a schematic diagram showing a part of the document table 19 in which the continuous portion 114 is provided on the third support portion 46. FIG. 9 is a schematic diagram showing the positioning member 140 provided with the continuous portions 141, 142, and 143. FIG. 10 is a schematic diagram schematically showing image data 148 which is an example of an image read by a conventional image reading apparatus.

DESCRIPTION OF SYMBOLS 10 ... Multifunction machine 11 ... Scanner part (an example of the image reading apparatus of this invention)
DESCRIPTION OF SYMBOLS 16 ... Holding member 19 ... Original stand 20 ... Contact glass (an example of the plate-shaped member of this invention)
22... Upper surface support frame (an example of the support frame of the present invention)
24. Image reading unit (an example of the reading unit of the present invention)
41 ... 1st end 42 ... 2nd end 43 ... 3rd end 45 ... 1st support part 47 ... Reference | standard position (an example of the reference | standard position of this invention)
49 ... Edge 50 ... Original 51, 52, 53, 54, 110, 111, 125, 126, 127, 128 ... Projection 70, 140 ... Positioning member 71, 72, 73, 74 , 113 ... 1st area | region 76 ... 2nd area | region 81,82,83,84,121,122,123,141,142,143 ... continuous part 100 ... control part (judgment of this invention Example)

Claims (5)

A transparent plate member whose outer edge is supported by a support frame and on which a document is placed;
A reading unit that is disposed on the back side of the plate-like member and starts image reading from a first end of the plate-like member toward a second end facing the first end;
A presser that is connected to the apparatus via a hinge, opens and closes with respect to the plate-like member, covers the upper surface of the plate-like member in a closed state, and presses the document placed on the plate-like member Members,
The first support portion of the support frame corresponding to the first end has a plurality of projecting portions projecting from the first support portion toward the plate-like member, and is placed on the plate-like member. The first side consisting of a straight line determined by the edges of the plurality of protrusions on the side of the plate-like member is brought into contact with the first side of the document. A positioning member for positioning at a reference position between the end and the second end;
A first region provided on the plate-like member, on the first end side with respect to the reference position and surrounded by the reference position and the support frame, and from the reference position to the second end. At least one continuous part that makes the second region continuous;
An image reading apparatus comprising: a determination unit configured to determine an edge on the first end side of the document placed in the second region based on the image data of the continuous unit read by the reading unit; . The positioning member is configured such that, of the edges of the document placed on the plate-like member, an edge on the third end side that intersects the first end of the plate-like member is brought into contact with the third edge. The end side edge is positioned at a second reference position on the plate-like member consisting of a straight line determined by a third support portion which is an end portion on the third end side of the support frame ,
The image reading apparatus according to claim 1, wherein one of the continuous portions includes an intersection of a virtual straight line along the reference position and a virtual straight line along the second reference position.   3. The image reading apparatus according to claim 1, wherein one of the continuous portions is provided at a position corresponding to a center position of the first end in the positioning member.   The image reading device according to claim 1, wherein the plurality of continuous portions are arranged along the first end. Upper Symbol continuous portion, the second between the first gap, and each adjacent ones of the plurality of protrusions set between one said support frame adjacent to the supporting frame of the plurality of projections Formed in each gap,
5. The image reading apparatus according to claim 1, wherein the pressing member covers the first gap and the second gap in addition to the second region.

Images