JP2018074324A - Image reading device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that automatic detection of a document size is performed in an image reading device but in the case of a document in a maximum size in which a size is unlikely to be determined or a document in a maximum size in which a manufacture error is considerable, a document size may not be detected since an end of a document is over a document size detectable region.SOLUTION: An image reading device comprises: contact glass 43; a placement stage frame 42 including a second read opening 46 for providing a light transmissible region while holding the contact glass; a document reading sensor 41; and a document pressing seat 37. The light transmissible region includes a document placement face 43a and a document placement outer surface 43b that protrudes therefrom in a main scanning direction. The document pressing seat 37 includes a protrusion 37b which is formed so as to be partially overlapped with the document placement outer face 43b. The document reading sensor 41 performs reading for performing medium size detection within a range of detectable regions (d3-d0) in which at least the document placement outer face 43b and the protrusion 37b are overlapped, in a sub scanning direction.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an image reading apparatus that reads an image of a document, and an image forming apparatus including the image reading apparatus.

  2. Description of the Related Art Conventionally, an image reading apparatus such as a copying machine or a scanner has a document table having a contact glass for placing the document in close contact for reading the document, an image reading unit disposed under the contact glass, white A document pressing unit including a document pressing sheet is also provided (see, for example, Patent Document 1), and the document size is automatically detected while the document is read.

JP2009-182949A (7th page, FIG. 4)

  In order to detect the document size of the maximum size document without being restricted by the light transmission area of the contact glass, the edge of the area where the document size can be detected is aligned with the edge of the document pressing sheet and the maximum size document. It only needs to be between the edges. However, since the light transmission area is actually determined by the size of the apparatus and the position of the document pressing sheet edge is constrained accordingly, it is possible to secure a sufficient distance between the document pressing sheet edge and the maximum size document edge. Difficult, when opening a standard-size booklet or notebook, etc., the maximum size of a document that is difficult to determine, or the maximum size of a document with a large manufacturing error, the edge of the document exceeds the area where the document size can be detected. In some cases, detection was not possible.

The image reading apparatus of the present invention includes a mounting glass for mounting a medium, a holding unit that holds the mounting glass and includes a reading opening for providing a light transmission region in the mounting glass, A reading unit that reads the medium placed on the glass through the mounting glass described above, and a medium pressing unit that can be opened and closed with respect to the mounting glass.
The light transmissive area is read from the original placement area in the original placement area where the medium is placed and a partial area of the original placement area in the sub-scanning direction orthogonal to the main scanning direction. A first projecting region projecting in the main scanning direction of the portion,
The medium pressing portion has a second projecting region formed so that the first projecting region and the region overlap in the first projecting region,
The reading unit performs reading for performing medium size detection within a range of a first area where at least the first protruding area and the second protruding area overlap in the sub-scanning direction. To do.

  According to the present invention, it is possible to perform document size determination reading from an area different from the document placement area, so that the document size cannot be detected when the edge of the document exceeds the document size detectable area. Can be prevented.

FIG. 1 is an external perspective view of an image forming apparatus according to Embodiment 1 of the present invention. In FIG. 1, it is the elements on larger scale of the part enclosed with the dotted line L. FIG. FIG. 2 is a main part configuration diagram of only the image reading unit in FIG. 1 as viewed from the right side (plus direction of the Y axis). FIG. 4 is a main part configuration diagram illustrating a state when the open / close unit is in a closed position in the image reading unit illustrated in FIG. 3. (A) is the elements on larger scale of the part enclosed with the dotted line M in FIG. 4, (b) is the elements on larger scale of the part enclosed in the dotted line N in FIG. FIG. 6 is a dimensional plan view showing an arrangement relationship of a document placing surface of a contact glass, a document pressing sheet, a sponge material, and dimensions of each part when the opening / closing unit is in a closed position. FIG. 3 is a block diagram illustrating a main configuration of a drive control system for an original size reading operation of an image reading unit according to the present invention. FIG. 6 is a diagram for explaining a document size reading operation of an image reading unit. It is a figure where it uses for description of the range setting of 3rd detection area Ad in a subscanning direction. FIG. 6 is a diagram for explaining a bundled A4 document 60 bound by a clip. (A) shows the example of formation of the drawing recessed part of this Embodiment, and the protrusion part of a document press sheet, The figure (b)-the figure (d) are the figures which show the modification.

Embodiment 1 FIG.
1 is an external perspective view of an image forming apparatus 1 according to Embodiment 1 of the present invention, and FIG. 2 is a partially enlarged view of a portion surrounded by a dotted line L in FIG. FIG. 1 shows a state where the opening / closing unit 22 is in an open position which will be described later.

As shown in FIG. 1, the image forming apparatus 1 straddles the image forming unit 11 with an image forming unit 11, an image reading unit 12 arranged above the image forming unit 11, and left and right support units 13L and 13R. A main body frame 13 that is disposed and holds the image reading unit 12 above the image forming unit 11 and integrally couples the image forming unit 11 and the image reading unit 12 is provided.
Hereinafter, when the image forming apparatus 1 is viewed from the front (in the direction of arrow A in FIG. 1), the up / down / left / right front / rear directions of the image forming apparatus 1 may be specified.

  The image reading unit 12 includes a flat bed unit 21, an opening / closing unit 22 rotatably held by the flat bed unit 21, and an operation unit 23 disposed at the front end of the flat bed unit 21. Includes a document pressing base 31 and an ADF (auto document feeder) 32 held by the document pressing base 31, and the document pressing base 31 is fixed to the lower surface of the pressing plate main body 35 and the pressing plate main body 35. A sponge material 36 as an elastic member, and a document pressing sheet 37 as a medium pressing portion joined to the lower surface of the sponge material 36 are provided.

  As will be described later, the flat bed unit 21 includes a document reading sensor 41 (FIG. 3) as a reading unit disposed in an inner space portion thereof, and a casing or a part thereof, and a first reading opening on an upper plane. 45 and a mounting table frame 42 as a holding portion in which a second reading opening 46 is formed, and a mounting glass attached to the lower surface of the mounting table frame 42 so as to cover the second reading opening 46 as a reading opening from the inside. Contact glass 43 (FIG. 3).

  The document 60 (FIG. 5) as a medium is placed on the surface of the contact glass 43. Here, as will be described later, the maximum A3 document 60 is placed in a landscape orientation (landscape) and read. Since it is assumed, the second reading opening 46 is formed in a substantially horizontally long rectangular shape so that the A3 reading document 60 can be placed on the surface of the contact glass 43.

  Left and right support portions 42L and 42R for pivotally supporting the opening / closing unit 22 are disposed in the vicinity of both end portions on the rear side of the mounting table frame 42, and the rotation axis center line is second read. The opening / closing unit 22 is pivotally supported so as to be in the longitudinal direction of the opening 46.

  1, the X, Y, and Z axes take the Y axis in the direction of the rotation axis of the opening / closing unit 22, and the X axis is perpendicular to the Y axis and parallel to the surface of the contact glass 43. The Z-axis is taken in a direction perpendicular to these two axes. Moreover, when each axis | shaft of X, Y, and Z is shown in the other figure mentioned later, these axial directions shall show a common direction. That is, the XYZ axes in each figure indicate the arrangement direction when the depicted portion of each figure constitutes the image forming apparatus 1 shown in FIG. Here, it is assumed that the Z-axis is arranged in a substantially vertical direction.

  FIG. 3 is a main part configuration diagram in which only the image reading unit 12 in FIG. 1 is viewed from the right side (plus direction of the Y axis). FIG. 4 is also a main part configuration diagram in which the opening / closing unit 22 is in a closed position described later. It shows a certain state. However, in FIGS. 3 and 4, the ADF 32 is omitted for simplicity. 5A is a partially enlarged view of a portion surrounded by a dotted line M in FIG. 4, and FIG. 5B is a partially enlarged view of a portion surrounded by a dotted line N in FIG. FIG. 5A shows a cross-sectional view in the region of the retracting recess 55 (FIG. 1) for convenience.

  As shown in these drawings, a document reading sensor 41 extending in the X-axis direction is disposed inside the flat bed unit 21. The document reading sensor 41 is slidably held in the Y-axis direction (sub-scanning direction) by a support guide 44 disposed below and extending in the Y-axis direction, and is further disposed at both ends thereof. The guide protrusions 41c and 41d (FIG. 4) are in contact with the lower surface of the contact glass 43 to maintain the sliding posture.

  The document reading sensor 41 has a light emitting element and a light receiving element arranged in the X-axis direction (main scanning direction) on the upper part thereof, for example, an image of the document 60 placed on the contact glass 43 in one line in the main scanning direction. The sensor part 41a (FIG. 4) read for every is provided.

  The document 60 is set on the contact glass 43 occupying the second reading opening 46 with the reading surface facing downward, and the setting position at this time is guided to the second reading opening 46 of the mounting table frame 42. A positioning guide is formed.

  That is, as shown in FIG. 5B, the first guide portion having a contact portion formed substantially perpendicular to the upper surface of the contact glass 43 at the rear long side portion of the second reading opening 46. The second positioning guide 51 is formed on the left short side portion of the second reading opening 46 and has a contact portion formed substantially perpendicular to the upper surface of the contact glass 43. A second positioning guide 52 (see FIG. 1) as a part is formed.

  A first step portion 53 and a second step portion as a restricting portion serving as a flange between the front long side portion and the right short side portion of the second reading opening 46 of the mounting table frame 42 and the upper surface of the contact glass 43. Step portions 54 are respectively formed. The first step portion 53 and the second step portion 54 regulate the displacement of the document 60 placed on the contact glass 43. In particular, the first step portion 53 has a document 60 as described later. , However, is restricted from moving forward from the document placement surface 43a beyond the first stepped portion 53.

  In the front long side portion of the second reading opening 46 of the mounting table frame 42, a retracting recess 55 is formed that is retracted from the first step portion 53 in the front direction (X-axis plus direction). The lead-in recess 55 is formed at the left end (on the second positioning guide 52 side) end of the front long side portion so as to cut out the first stepped portion 53, and the light transmission of the contact glass 43 at this portion. Expanding the area.

  Further, the rectangular area of the contact glass 43 on which the original 60 can be placed in the second reading opening 46 may be hereinafter referred to as an original placement surface 43a as an original placement area. Therefore, the document placement surface 43 a does not include the document placement outer surface 43 b as a first projecting region that is a light transmission region of the contact glass 43 spread by the drawing recess 55. The boundary between the document placement surface 43a and the document placement outer surface 43b is indicated by a boundary line (dotted line) B1 (FIG. 1 and the like).

  Accordingly, when the operator sets the document 60 on the contact glass 43, the rear side and the left side of the document 60 are respectively connected to the first positioning guide 51 and the second positioning guide 52 of the mounting table frame 42. Position by abutting.

  On the other hand, the pressing plate main body 35 of the opening / closing unit 22 has a document pressing sheet 37 disposed at a position facing the contact glass 43 when the opening / closing unit 22 is in the closed position, and the document pressing sheet 37 is interposed via the sponge material 36. The press plate body 35 is fixed. Therefore, as shown in FIG. 4, when the opening / closing unit 22 is in the closed position, the document 60 (FIG. 5) set on the document placement surface 43 a of the contact glass 43 has the weight of the opening / closing unit 22 and the sponge material 36. Due to elasticity or the like, the original pressing sheet 37 urges the original placing surface 43 a substantially uniformly and comes into close contact with the contact glass 43.

  In the vicinity of the support portions 42L and 42R, an open / close detector 103 (shown only in FIG. 7) for detecting when the open / close unit 22 is in the open position shown in FIG. 3 and in the closed position shown in FIG. Has been placed.

  FIG. 6 shows a light transmission region (document placement surface 43a + document placement outer surface 43b) of the contact glass 43 occupying the second reading opening 46, a document pressing sheet 37, and a sponge when the opening / closing unit 22 is in the closed position. It is a dimension top view which shows the arrangement | positioning relationship of the material 36, and the dimension of each part. In the figure, the first reading opening 45 (FIG. 1) is omitted.

  As shown in the figure, the sponge material 36 and the document pressing sheet 37 are formed to have the same outer shape as viewed from above (Z-axis plus side), and transmit light through the contact glass 43 occupying the second reading opening 46. The shape and the mounting position are determined so as to be smaller and substantially similar to the area (document placement surface 43a + document placement outer surface 43b) and not to protrude from the opening.

  Therefore, here, the shape of the original pressing sheet 37 will be described as an example. The original pressing sheet 37 includes a rectangular original pressing portion 37a and a protruding portion 37b as a second protruding region. The protruding portion 37b is an original of the contact glass 43 that appears by the drawing recess 55 of the second reading opening 46. It is formed at a position facing the mounting outer surface 43b. The boundary between the document pressing portion 37a and the protruding portion 37b is indicated by a boundary line (dotted line) B2 (FIG. 6 and the like).

  Here, the shape (corresponding to the opening shape of the second reading opening 46) of the light transmission region (the original placing surface 43a + the original placing outer surface 43b) of the contact glass 43 occupying the second reading opening 46, the sponge material 36, and the original pressing A dimension example of each part of the sheet 37 will be described.

As described above, it is assumed that the image reading unit 12 reads and reads a maximum of A3 read original 60 on the original placement surface 43a of the contact glass 43 occupying the second reading opening 46 in a horizontally long (horizontal) manner. doing. Therefore, the length a in the short direction of the document placement surface 43a is set to 301 mm,
Longitudinal length b is 435.8 mm
age,
The drawing width c of the document placement outer surface 43b is 6.5 mm.
Tip width d is 70mm
The width e in the longitudinal direction of the chamfered portion formed at the end of the retracting recess 55 opposite to the second positioning guide 52 side is 6.5 mm.
It was.
Further, the length g in the short direction of the document pressing portion 37a excluding the protruding portion 37b of the document pressing sheet 37 is 299.5 mm,
Longitudinal length h is 433 mm
age,
The clearance i between the document pressing sheet 37 and the document placement surface edge in the longitudinal direction is 1.4 mm.
age,
The gap j between the document pressing surface 37 excluding the protrusion 37b and the document placement surface end in the short direction is 0.75 mm.
age,
Further, the protruding width k of the protruding portion 37b of the original pressing sheet 37 is set to 3.75 mm.
The width m of the tip is 59.1 mm,
The width n in the longitudinal direction of the chamfered portion formed at the end of the protruding portion 37b opposite to the second positioning guide 52 side was set to 4 mm.
The sponge material 36 has the same external dimensions as the original pressing sheet 37 and is disposed at the same position.

  Accordingly, when the opening / closing unit 22 is in the closed position, most of the protrusion 37b of the document pressing sheet 37 protrudes from the document placement surface 43a of the contact glass 43 over at least the width (59.1) mm. It contacts the area of the outer surface 43b. FIG. 5A is a cross-sectional view in the area of the pull-in recess 55 when the A4 original 60 is placed vertically and the open / close unit 22 is closed. As shown in FIG. Then, the original 60 is pressed by the original pressing portion 37a, and is in close contact with the contact glass 43 in a region facing the original placement surface 43b from the original placement surface 43a.

  Inside the flat bed unit 21, a first paper sensor 48 and a second paper sensor 49 are arranged at different positions in the sub-scanning direction (Y-axis direction) shown in FIG. The placed document 60 is placed horizontally (here, the main scanning direction (X-axis direction) is the short side) or vertically (here, the main scanning direction (X-axis direction) is the long side). To determine.

  FIG. 7 is a block diagram showing the main configuration of the drive control system for the document size reading operation of the image reading unit 12 according to the present invention. FIG. 8 is a diagram for explaining the document size reading operation of the image reading unit 12. FIG.

  In the figure, the open / close detector 103 detects when the open / close unit 22 is in the open position shown in FIG. 3 and in the closed position shown in FIG. Send to. As shown in FIG. 6, the first paper sensor 48 and the second paper sensor 49 are arranged at different positions in the sub-scanning direction (Y-axis direction) in the region of the document placement surface 43a of the contact glass 43, and at each position. Information on whether or not a document is detected is individually transmitted to the control unit 100.

  The control unit 100 as a medium detection unit includes a microprocessor, a ROM, a RAM, an input / output port, a timer, and the like. The control information about the open / close unit 22 from the open / close detector 103 and the first and second paper sensors 48 are provided. , 49, etc., the entire image reading unit 12 is sequence-controlled, and an operation for reading the document size is executed.

  The sensor driving unit 101 executes movement of the document reading sensor 41 in the sub-scanning direction and data reading in the main scanning direction by the sensor unit 41a in accordance with an instruction from the control unit 100. The document reading sensor 41 transmits the read image data that has been read to the control unit 100.

  With reference to FIG. 8, a method of reading the document size by the control unit 100 will be further described.

  FIG. 8 shows the original placement surface 43a and the original placement outer surface 43b of the contact glass 43 in the vicinity of the second positioning guide 52 in a state where the read original 60 is set at a predetermined position and the opening / closing unit 22 is closed, FIG. 6 is a plan view schematically showing the positional relationship of 60, a document pressing sheet 37, a sponge material 36, and a document reading sensor 41.

  The first reading opening 45 (FIG. 1) is an opening through which the document reading sensor 41 reads a document conveyed by the ADF 32. However, the configuration and operation thereof are not directly related to the present invention. The first reading opening 45 (FIG. 1) is omitted in FIG.

  In the figure, an original reading sensor 41 that slides in the sub-scanning direction (Y-axis direction) is a home position as a standby position outside the second reading opening 46 and in the vicinity of the left end of the flat bed unit 21 (FIG. 1). Located in Ph. Here, the home position Ph indicates the position in the sub-scanning direction of the sensor unit 41a of the document reading sensor 41 that reads one line in the main scanning direction (X-axis direction). Similarly, when the position of the document reading sensor 41 in the sub-scanning direction is indicated, the position of the sensor unit 41a is indicated.

  Further, the distance w1 indicates the distance from the first positioning guide 51 to the front end of the document pressing portion 37a of the document pressing sheet 37, and the distance w2 is placed from the first positioning guide 51. The distance w3 is the distance from the first positioning guide 51 to the first step portion 53 (in the short direction of the document placement surface 43a of the contact glass 43). The distance w5 indicates the distance from the first positioning guide 51 to the front end of the protrusion 37b of the document pressing sheet 37.

  Further, the distance w4 (for example, 302.4 mm) is a distance from the first positioning guide 51 at the front side end portion of the first detection area Aw for detecting a vertically placed A4 size document 60, which will be described later. The distance w0 (for example, 262.6 mm) is a distance from the first positioning guide 51 at the front end of the second detection area Bw for detecting a vertically placed B5 size document, which will be described later. Indicates distance.

  When the operator sets the document 60 on the document placement surface 43 a of the contact glass 43, the operator first rotates the opening / closing unit 22 (FIG. 1) to the open position, and the prepared document 60 is moved to the first positioning guide 51 and The opposite positioning sides are abutted and positioned on the second positioning guide 52 and set.

  Therefore, the control unit 100 monitors the open / close detection information received from the open / close detector 103 and the original detection information from the first and second paper sensors 48 and 49, and opens / closes the document 60 when the original 60 is not set. When it is detected that the unit 22 (FIG. 1) is in the open position, it is determined that the document 60 is set, and the sensor driving unit 101 is instructed to move the document reading sensor 41 to the reading movement start position Ps. Upon receiving this instruction, the sensor driving unit 101 moves the document reading sensor 41 from the home position Ph to the reading movement start position Ps.

  Next, when the control unit 100 detects that the open / close unit 22 (FIG. 1) is closed in a state where the document 60 is set on the document placement surface 43 a of the contact glass 43, the size of the set document 60 is detected. Start reading.

  First, the control unit 100 controls the document reading sensor 41 via the sensor driving unit 101, and sequentially performs main scanning by the sensor unit 41a while moving in the sub scanning direction from the reading movement start position Ps toward the home position Ph. The image is scanned in the direction, the image of the reading area Ve indicated by a two-dot chain line in FIG. 8 is read, and the read image data received from the document reading sensor 41 is temporarily stored in a storage means such as a RAM.

  Based on the image information of the reading area Ve, the control unit 100 performs the first detection area Aw and the second detection area Bw as the second specific area in the main scanning direction illustrated in FIG. On the same line in the main scanning direction toward the first positioning guide 51 (in the direction of arrow C) in a third detection area Ad (here, the area from d1 to d0) as a first specific area in the sub-scanning direction to be described later. The image data corresponding to this position is sequentially read out, line scanning is performed to detect the front end of the document 60, and the distance w2 from the first positioning guide 51, that is, the size of the document 60 in the main scanning direction is detected. . This line scanning can be performed at a plurality of locations in the sub-scanning direction, and the average of the detected distances w1 can be calculated.

  The detection of the front side edge of the document 60 is performed, for example, by determining a shadow generated between the background document pressing sheet 37 and the front side edge of the document 60. For this reason, in order to avoid confusion with the image data of the document, the first detected shadow detected at the foremost side in the first detection area Aw or the second detection area Bw is determined as the near edge of the document 60. In this case, when the first detection shadow is detected in the first detection area Aw, the document 60 is determined to be an A4 portrait document, and the first detection shadow is detected in the second detection area Bw (its width is 41.4 mm, for example). Is detected, the document 60 is determined to be a B5 portrait document.

Further, here, the distance d1 from the second positioning guide 52 of the reading movement start position Ps for starting the document size reading is based on the distance d2 from the second positioning guide 52 at the right end of the tip of the protruding portion 37b. A short region that is longer than the distance d0 from the second positioning guide 52 to the end of the document pressing sheet 37, that is,
d2>d1> d0 (1-1)
Set to
Here, the distances w1 to w5 from the first positioning guide 51 to each part are as follows.
w5>w4>w3> w2 (2-1)
Meet the relationship.
Further, since the near end of the A4 size document 60 needs to be within the range of the first detection area Aw, here,
w2> w4-wa (the width of the first detection area Aw, for example, 17.8 mm)
(2-2)
It is necessary to satisfy the relationship.

In principle, the distance d1 of the reading movement start position Ps from the second positioning guide 52 is the second positioning where the protruding portion 37b of the document pressing sheet 37 exceeds the extension line of the first step portion 53. Shorter than the distance d3 from the guide 52 d3>d1> d0 (1-2)
However, in this case, during the distances d3 to d2, the maximum value of the distance w4 also changes from the distances w3 to w5 according to the position of the distance d1. The range from the distance d3 to the distance d0 corresponds to the first region.

  The setting of the third detection area Ad as the first specific area in the sub-scanning direction will be further considered. FIG. 9 is a diagram for explaining the setting of the range of the third detection area Ad in the sub-scanning direction, and FIG. 10 is a diagram for explaining the A4 original 60 in a bundle bound by the clip 110.

  In FIG. 9, a two-dot chain line outline 70 is an outline when the A4 document is set vertically, and a two-dot chain line outline 71 is an outline when the B5 document is set vertically. is there. On the other hand, as shown in FIG. 10, there is an original in which a plurality of A4 originals 60 are overlapped and one end portion of a short side is bound by a binding member such as a clip 110 or a staple. In the case of copying the original 60, for example, a few originals from above, the original on the upper side is turned up around the fold 60a, and the copy surface that appears is the original placement surface 43a shown in FIG. And set at the position of the outline 70 of the two-dot chain line. Here, a case where the clip 110 is set to face the second positioning guide 52 will be considered.

  The contact standard line 70a in FIG. 9 is a line that conveniently indicates the boundary between the copy surface of the document 60 and the document placement surface 43a, which is opposed to the fold line 60a, between the copy surface and the document placement surface 43a. In the case of a B5 document that is copied under the same conditions, a similar contact guide line 71a is generated. Note that the positions of the contact guide lines 70a and 71a vary depending on the type of the binding member, the type of the original, various conditions, and the like.

  When the distance from the second positioning guide 52 at the right end portion of the adhesion guide line 70a is de, and the size in the short direction of the B5 document set vertically is ds (for example, 182 mm), the sub-scanning direction It is necessary that the third detection area Ad is present in the range of the distance ds to the distance de. Here, the distance ds is determined on the assumption that size detection is performed up to a vertically placed document of paper size B5. However, when the minimum size of a document whose size is to be detected, such as a vertically placed document of A5, is different, the distance ds is determined accordingly. The distance ds is set as appropriate.

  In addition, as an example of dimensions of each part in the present embodiment, an example in which the drawing width c = 6.5 mm and the leading end width d = 70 mm on the document placement outer surface 43b is shown. However, the present invention is not limited to this. The pulling width c is preferably set in the range of 3 mm to 20 mm. Further, the tip end width d is 31.5 mm to 147 mm (15% to 70% of the length in the A4 short direction 210 mm), more preferably 42 mm to 105 mm (20% to 50% of the length A210 in the short direction 210 mm). ) Is preferably set within the range. At this time, the projecting width k and the tip end width m of the corresponding projecting portion 37b may be set so that the gap i and the gap j fall within the range of 0.5 mm to 2 mm, respectively.

  As described above, the third detection area Ad is an image data range used in the sub-scanning direction for the control unit 100 to determine the size of the document 60 based on the image information of the reading area Ve by software processing. Indicates. Therefore, if the third detection area Ad is present beyond the distance ds, the B5 original placed in the vertical position may not be detected. If the third detection area Ad exists below the distance de, the bound original is set. May not be detected. The width of the third detection area Ad changes according to the software processing. When the size is determined using only one line of image data, the third detection area Ad has a width corresponding to one line, and the image data of a plurality of lines is used. Is the width including the line to be used.

  In FIG. 11, in order to secure the third detection area Ad in the range of the distance ds to the distance de, the drawing recess 55 formed in the mounting table frame 42 (FIG. 9) and the document pressing sheet 37 facing this are shown. It is a figure which shows the example of formation with the protrusion part 37b formed. FIG. 11A shows an example of forming the drawing recess 55 and the projection 37b of the document pressing sheet 37 according to the present embodiment, and FIGS. In FIG. 11, the sponge material 36 (FIG. 6) is formed so as to have the same outer shape as the original pressing sheet 37.

  FIG. 9A shows an example in which, as shown in FIG. 9, for example, the drawing recess 55 is formed at the left end portion of the second reading opening 46 and the protruding portion 37b is similarly formed at the left end portion of the document pressing sheet 37. . In this case, the third detection area Ad can be set to a part or all between the distance d2 (FIG. 8) and the distance de.

  FIG. 4B shows a case where the width region of the leading end portion of the protruding portion 37b of the document pressing sheet 37 is formed so as to coincide with or include the range of the distance ds to the distance de. In this case, the third detection area Ad can be set to a part or all between the distance ds and the distance de.

  FIG. 4C shows a case where the width region of the tip end portion of the protruding portion 37b of the original pressing sheet 37 is formed so as to be within the range of the distance ds to the distance de. In this case, the third detection region Ad can be set to a part or all of the width of the tip portion of the protruding portion 37b.

  FIG. 4D shows a case where the width region of the leading end portion of the protruding portion 37b of the original pressing sheet 37 is formed so as to straddle the distance ds. In this case, the distance from the second positioning guide 52 to the left end of the tip of the projecting portion 37b is d9, and the third detection area Ad is set to a part or all between the distance ds and the distance d9. can do.

  Further, in the reading area Ve shown in FIG. 8, an image is read at least in an area defined by the third detection area Ad described in FIG. 11 and the first detection area Aw or the second detection area Bw. Must be set to

  According to the configuration shown in FIG. 11A, the reading movement start position Ps can be set closer to the home position Ph than in the configurations shown in FIGS. It can be said that it is advantageous to increase the speed.

  Based on the detected distance w2 and the original detection information from the first paper sensor 48 and the second paper sensor 49, the control unit 100 determines the paper size and arrangement direction of the original set on the original placement surface 43a of the contact glass 43. Identify.

  For example, when the distance w2 is 297 mm and both the first paper sensor 48 and the second paper sensor 49 detect paper, it is determined that the set document is A3 paper and is placed horizontally, and the distance w2 is 297 mm. When only the first sheet sensor 48 detects the sheet, it is determined that the set document is A4 sheet and is placed vertically. Similarly, for example, paper size B5 (vertical / horizontal), A4 (vertical / horizontal), B4 (horizontal), and A3 (horizontal) can be determined.

  In the present embodiment, in the course of the document size reading operation, the image of the reading area Ve indicated by a two-dot chain line in FIG. 8 is read and temporarily stored in the storage means, and then the stored image data is used as the basis. FIG. 8 shows a method for obtaining the paper size of the document. However, the present invention is not limited to this. For example, the first detection area Aw and the second detection area Bw shown in FIG. 8 and the third detection area Ad shown in FIG. In the detection area to be filled, the image data on the same line in the main scanning direction toward the first positioning guide 51 indicated by the arrow C in FIG. Good.

  Further, in the present embodiment, the opening / closing unit 22 is configured to rotate about the rotation axis extending in the sub-scanning direction on the rear side of the mounting table frame 42, but the right or left side of the opening / closing unit 22. It is possible to adopt various modes, such as a configuration in which the end portion of the shaft may be rotated about the rotation axis extending in the main scanning direction.

  As described above, according to the image reading unit 12 of the present embodiment, as shown in FIG. 8, the contact recess 55 (FIG. 6) protruding forward from the first step portion 53 is formed. Since the document placement outer surface 43b is generated on the glass 43, and the protrusion 37b of the document pressing sheet 37 is formed so as to overlap the document placement outer surface 43b, the front end of the first detection area Aw is set to the first end. It is possible to set up to the position of the distance w5 at the maximum on the near side beyond the one step portion 53.

  For this reason, it is possible to detect the document size even when the document 60 set on the document placement surface 43a is set to be shifted to the near side to the first step portion 53 in the worst case. Note that the position of the original 60 is restricted by the first step portion 53, and therefore, the document 60 does not move to the near side from the first step portion 53.

  Incidentally, when the document placement outer surface 43b and the projection 37b of the document pressing sheet 37 are not formed, the distance w1 from the first positioning guide 51 of the front end of the document pressing portion 37a of the document pressing sheet 37 is Since it is a paper detectable area in the main scanning direction, the paper detectable area in the main scanning direction is limited and may not be detected in some cases.

  Therefore, according to the image reading unit 12 of the present embodiment, the sheet detection area can be expanded beyond the area of the document placement surface 43a in the main scanning direction, so that the document is placed on the document placement surface 43a. The paper size can be determined even when the paper is set up to the end in the main scanning direction. Further, since the retracting recess 55 can be formed within a range in which the outer shape of the mounting table frame is not changed, it is possible to contribute to downsizing of the apparatus.

  Further, as shown in FIG. 5A, the protruding portion 37b of the document pressing sheet 37 is pressed by the sponge material 36 formed in the same outer shape, so that the document reaches, for example, the position of the first step portion 53. Even if they deviate, they are brought into close contact with the document placement outer surface 43b without being lifted, thereby preventing erroneous detection during image reading.

  In the above description of the embodiment, the words “up”, “down”, “left”, “right”, “front”, “back” are used for convenience, and image formation is performed. The absolute positional relationship in the state in which the device is arranged is not limited.

  In the above-described embodiment, the example in which the present invention is applied to the image reading apparatus has been described. However, the present invention is not limited to this, and the present invention is also applicable to an MFP (Multi Function Printer), a facsimile, a copying machine, and the like. Available.

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 11 Image forming part, 12 Image reading part, 13 Main body frame, 13L Left support part, 13R Right support part, 21 Flat bed unit, 22 Opening / closing unit, 23 Operation part, 31 Original press base | substrate, 32 ADF, 35 pressing plate body, 36 sponge material, 37 original pressing sheet, 37a original pressing portion, 37b protruding portion, 41 original reading sensor, 41a sensor portion, 41c guide protrusion, 41d guide protrusion, 42 mounting table frame, 42L left support portion, 42R Right support part, 43 Contact glass, 43a Document placement surface, 43b Document placement outer surface, 44 Support guide, 45 First reading opening, 46 Second reading opening, 48 First sheet sensor, 49 Second sheet sensor, 51 First positioning guide 52 second positioning guide 53 First step, the second step portion 54, 55 pull recess 60 document, 100 controller, 101 sensor driver, 103 opening and closing detector.

Claims (13)

A mounting glass for mounting a medium;
A holding unit having a reading opening for holding the placement glass and providing a light transmission region in the placement glass;
A reading unit that reads the medium placed on the placement glass through the placement glass;
A medium presser portion that is openable and closable with respect to the mounting glass, and
The light transmission region is
A document placement area on which the medium is placed;
A first projecting region projecting in the main scanning direction of the reading unit from the document placing region in a partial region of the document placing region in the sub-scanning direction orthogonal to the main scanning direction;
The medium pressing portion has a second projecting region formed so that the first projecting region and the region overlap in the first projecting region,
The reading unit performs reading for performing medium size detection within a range of a first area where at least the first protruding area and the second protruding area overlap in the sub-scanning direction. An image reading apparatus.   The holding portion is a restriction that restricts movement of the medium between the holding plate and the glass on the edge of the opening corresponding to the side in contact with the first projecting region of the document placement region formed in a square shape. The image reading apparatus according to claim 1, further comprising a unit.   The holding unit is a first unit for positioning the medium between the document placement region and the placement glass at an edge of an opening corresponding to a side facing the regulation unit of the document placement region formed in a square shape. A second portion for positioning the medium between the document placement area and the glass on the edge of the opening corresponding to the side perpendicular to the restriction portion of the document placement area formed in a square shape. The image reading apparatus according to claim 2, further comprising a guide unit.   The reading unit is held movably in the sub-scanning direction, and has a standby position outside the document placement area on the second guide unit side in the sub-scanning direction. The image reading apparatus according to 3.   The image reading apparatus according to claim 4, wherein the first protruding area is formed at an end of the document placement area on the standby position side in the sub-scanning direction.   Medium size detection based on read data within the first specific area within the first area among the read data read within the range of the first area with the reading unit in the sub-scanning direction The image reading apparatus according to claim 3, further comprising a medium detection unit that performs the operation. When the first distance in the sub-scanning direction from the second guide part is ds and the second distance in the sub-scanning direction from the second guide part is de, the first specific region Relationship with
de <first specific region <ds
The image reading apparatus according to claim 6, wherein the image reading apparatus is configured as follows.   8. The image reading apparatus according to claim 7, wherein the first distance ds is a length of a short side of an A4 size medium or an A5 size medium.   9. The medium detection unit according to claim 6, wherein the medium detection unit performs medium size detection based on read data read by the reading unit within a range of a second specific area in the main scanning direction. The image reading apparatus according to claim 1.   The image reading apparatus according to claim 9, wherein an end of the second specific area on the second protruding area side is a position where the first protruding area and the second protruding area overlap each other. .   When the medium bound by the binding member is placed on the placement glass with the binding member set to the second guide side and pressed by the medium presser, the placement glass and the presser 9. The image reading apparatus according to claim 7, wherein the second distance is a maximum distance from the second guide portion that is separated from the second guide portion.   12. The medium pressing portion according to claim 1, wherein the medium pressing portion is held by the pressing plate main body via an elastic member, and the elastic member is interposed in all regions at least in the second projecting region. The image reading apparatus described in 1. An image forming apparatus comprising the image reading apparatus according to claim 1.

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