JP6531517B2 - Image reader - Google Patents

Description

  The present invention relates to an image reading apparatus represented by a scanner.

  A scanner, which is an example of an image reading apparatus, in particular, a so-called flatbed scanner that places and reads an original on an original glass is provided with an original conveying device (also called ADF (Auto Document Feeder)). It may be configured to be able to automatically feed and read The automatic document feeder conveys the document to the reading position, and the reading means reads the document being fed while being stopped at the reading position.

  A document glass is provided with a document glass for reading a document conveyed by a document conveyance device, and a document glass which is formed in a size to cover the entire document and on which the document is placed. The reading unit reads the document conveyed by the document conveyance device while being stopped at a position facing the former document glass. Further, the reading unit reads the entire original by moving in a predetermined direction (sub-scanning direction) relative to the original in a region facing the latter original glass.

  Here, when the document conveyed by the document conveying device is conveyed while being in contact with the document glass at the reading position, the scratch is formed on the glass surface, or foreign matter such as paper dust or glue adhering to the document is It adheres to the glass surface and there is a possibility that reading failure may occur. Therefore, conventionally, as shown in Patent Documents 1 and 2, a sheet member is provided slightly before the reading position, a gap is formed between the document and the glass surface by this sheet member, and the document to be conveyed is on the document glass. Some have been devised to avoid contact.

JP-A-09-307695 Japanese Patent Application Publication No. 2007-221590

  By the way, in recent years, further miniaturization of the image reading apparatus is required. On the other hand, the reading sensor of the image reading apparatus includes a reduction optical system method and a contact optical system method. In the reduction optical system, the optical system becomes complicated and the apparatus becomes large, but the depth of field is deep because the optical path length can be taken long, and focusing is easy even if the document is not in close contact with the document glass. On the other hand, in the contact optical system method, although the optical system is simple and the size can be reduced, the depth of field becomes shallow because the optical path length is short, and focusing is not achieved if the document is not in close contact with the document glass. It has the nature.

  In order to meet the demand for further miniaturization in recent years, it is preferable to adopt the contact optical system method, but in the image reading apparatus up to now, the original conveyed by the original conveying apparatus is floated from the original glass In the reading and further reading of the document while the reading sensor moves in the sub-scanning direction in the flatbed region, no special consideration has been made for adopting the contact optical system.

  Therefore, the present invention has been made in view of such a situation, and an object thereof is to consider the miniaturization of the apparatus while appropriately performing both reading by automatic document conveyance and reading by movement of a reading sensor. An object of the present invention is to provide an image reading apparatus.

  An image reading apparatus according to a first aspect of the present invention for solving the above problems comprises: an original conveying means for conveying an original to an original reading position; a first transparent member provided at the original reading position; A second transparent member on which a document is placed, which is juxtaposed to a first transparent member, and movably provided along the first transparent member and the second transparent member, the first transparent member and the second transparent member. Reading means for reading a document through a transparent member, a gap is formed between the document and the first transparent member at the document reading position, and the size of the gap is s, the first transparent member The refractive index of the first transparent member t1, the refractive index of the second transparent member n2, the thickness of the second transparent member t2, the top surface of the reading lens provided with the reading means and the first The distance to the transparent member is d1, the reading When the distance between the upper surface of the lens and the second transparent member is d2, the value obtained by [s + t1 / n1 + d1] and the value obtained by [t2 / n2 + d2] are the same or substantially equal. I assume.

  In paraxial optics, the optical path length when light is incident perpendicularly to a plane-parallel plate of thickness t and refractive index n is equivalent to the optical path length t / n in air. According to this, in this embodiment, the optical path length at reading by automatic document conveyance [s + t1 / n1 + d1] and the optical path length at reading by movement of the reading means [t2 / n2 + d2] are configured to be equal or almost equal. . As a result, regardless of the configuration of the reading means, good images can be obtained in both reading by automatic document conveyance and reading by movement of the reading means. In addition, since a gap s is formed between the first transparent member and the document at the time of reading by automatic document conveyance, it is possible to avoid the problem of forming a scratch or the like on the first transparent member.

  A second aspect of the present invention is characterized in that, in the first aspect, the distance d1 and the distance d2 are the same or substantially equal, and the thickness t2 is set in accordance with the gap s + the thickness t1. I assume.

  According to a third aspect of the present invention, in the first aspect, the thickness t1 and the thickness t2 are the same or substantially the same, and the refractive index n1 and the refractive index n2 are the same or substantially the same. I assume.

  According to this aspect, the thickness t1 of the first transparent member and the thickness t2 of the second transparent member are the same or substantially the same, and the refractive index n1 of the first transparent member and the thickness of the second transparent member Since the refractive index n2 is the same or substantially the same, the same material can be used for the first transparent member and the second transparent member, and the cost of the device can be reduced.

  According to a fourth aspect of the present invention, in the first aspect, a sheet material of thickness g is attached to the side facing the reading means in the second transparent member, and a part of the reading means is attached to the sheet material By contacting, a part of the distance d2 is characterized by the thickness g.

  According to this aspect, the sheet material of thickness g is attached to the side facing the reading means in the second transparent member, and a part of the reading means is in contact with the sheet material, so that Since the thickness g constitutes a portion, the distance d2 can be easily adjusted even when the thicknesses of the first transparent member and the second transparent member are different.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a surface of the first transparent member facing the reading means, and a surface of the second transparent member facing the reading means , Is characterized by being coplanar.

  According to this aspect, since the surface of the first transparent member facing the reading unit and the surface of the second transparent member facing the reading unit are flush with each other, the reading unit is the first transparent member. When moving from the position facing the transparent member to the position facing the second transparent member, or when moving in the opposite direction, since there is no level difference, it can be moved smoothly.

Further, in the case where the reading unit is configured to be pressed against the first transparent member and the second transparent member, the biasing force at that time changes between the case of the first transparent member and the case of the second transparent member. Can be avoided and good reading accuracy can be maintained.
In addition, "the same level" means that there is no difference in level between the surface of the first transparent member facing the reading means and the surface of the second transparent member facing the reading means. In addition, it is a meaning that also includes a state in which a slight level difference is generated due to a deviation in part accuracy or assembly accuracy.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the reading means includes a first protrusion and a second protruding relative to the first transparent member and the second transparent member. A protrusion is provided, and when the reading means is in a position facing the first transparent member, only the first protrusion of the first and second protrusions contacts the first transparent member. Thus, when the distance d1 is defined and the reading means is at a position facing the second transparent member, only the second protrusion among the first protrusion and the second protrusion may be the second. A configuration is provided in which the distance d2 is defined by being in contact with a transparent member.

  According to this aspect, since the first protrusion and the second protrusion provided in the reading unit respectively define the intervals d1 and d2, the intervals d1 and d2 can be simplified. Can be adjusted to a low cost.

  According to a seventh aspect of the present invention, there is provided an original conveying means for conveying an original to an original reading position, a first transparent member provided at the original reading position, and an original placed side by side with the first transparent member. A second transparent member to be read, and a reading unit provided so as to be movable along the first transparent member and the second transparent member, and reading an original via the first transparent member and the second transparent member; A clearance is formed between the document and the first transparent member at the document reading position, and the reading means slides along the first transparent member and the second transparent member. The distance from the sliding surface to the document separated from the first transparent member and the distance from the sliding surface to the document mounting surface of the second transparent member are as follows. The document is aligned so that the document is in focus within the depth of field of the reading means. It is characterized in that is.

  According to this aspect, the distance from the sliding surface of the reading means to the document separated from the first transparent member, and the distance from the sliding surface to the document placement surface of the second transparent member However, since the document is aligned so that the document is in focus within the depth of field of the reading means, regardless of the configuration of the reading means, in both reading by automatic document conveyance and reading by movement of the reading means Good image is obtained. In addition, since a gap is formed between the first transparent member and the document at the time of reading by automatic document conveyance, the problem of forming a scratch or the like on the first transparent member can be avoided.

FIG. 1 is an external perspective view of a scanner according to the present invention. FIG. 1 is an external perspective view of a scanner according to the present invention. FIG. 2 is a side sectional view of a scanner according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The principal part side sectional view of the scanner which concerns on this invention. The partially expanded perspective view of a reading part. FIG. 7 is a plan view showing the relationship among the reading unit, the first original glass, and the second original glass. FIG. 3 is a diagram showing a positional relationship between a reading unit and a document. BRIEF DESCRIPTION OF THE DRAWINGS The side sectional view (schematic diagram) of a scanner which shows 1st Embodiment of this invention. The side sectional view (schematic diagram) of the scanner which shows a 2nd embodiment of the present invention. The side sectional view (schematic diagram) of the scanner which shows a 3rd embodiment of the present invention. The top view which shows these relationships of the reading part in 1st Embodiment of this invention, 1st original glass, and 2nd original glass. The principal part front view of a reading part which shows 3rd Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described based on the drawings, but the present invention is not limited to the embodiment described below, and various modifications are possible within the scope of the invention described in the claims. On the premise that they are also included in the scope of the present invention, one embodiment of the present invention will be described below.

  1 and 2 are external perspective views of the scanner 1 according to the present invention, FIG. 3 is a side sectional view of the scanner 1, FIG. 4 is a side sectional view of the main part of the scanner 1, and FIG. 6 is a plan view showing the relationship among the reading unit 5, the first original glass 3 and the second original glass 4, and FIG. 7 is a view showing the positional relationship between the reading unit 5 and the original.

  FIG. 8 is a side sectional view (schematic view) of the scanner showing the first embodiment of the present invention, and FIG. 9 is a view showing the second embodiment. Furthermore, FIG. 10 is a side sectional view (schematic view) of a scanner showing a third embodiment of the present invention, and FIG. 11 is a reading unit 5C, a first document glass 3C, and a second document glass 4C in the third embodiment. A plan view showing these relationships, and FIG. 12 is a front view of an essential part of a reading unit 5C showing a third embodiment.

Note that FIGS. 1 to 7 are diagrams for explaining the configuration common to the first to third embodiments shown in FIG. 8 and the subsequent figures, and the components related to the first to third embodiments are mainly described. It shows according to 1st Embodiment.
In the xyz coordinate system shown in each drawing, the x direction is the document width direction, which is the main scanning direction from the viewpoint of the reading unit 5, and the y direction is the sheet conveyance direction, the viewpoint of the reading unit 5 In this case, the sub scanning direction is used, and the z direction is the apparatus height direction and the vertical direction.

The general configuration of the scanner 1 as an example of the image reading apparatus according to the present invention will be outlined below. In FIGS. 1 to 3, a scanner 1 as an image reading apparatus is provided with a document conveying device (ADF (Auto Document Feeder)) 20 as a document conveying unit on the upper part of a scanner main body 2. The document conveying device 20 can set a plurality of documents (symbol M1 in FIG. 3), and feeds the documents M1 set toward the reading position in the scanner body 2 one by one.
The scanner body 2 reads the document conveyed by the document conveyance device 20.

Reference numeral 21 indicates a feed tray. The document M 1 is placed on the feed tray 21. The feed tray 21 is provided with edge guides 23A and 23B for guiding both sides of the set document M1. The edge guides 23A and 23B are provided displaceably in the width direction of the document M1 (direction orthogonal to the feeding direction), and are also mutually approaching or separated from each other by a rack and pinion mechanism (not shown). It is provided to be displaced.
Reference numeral 33 denotes a discharge tray for receiving the document M1 to be discharged after the reading is completed.

The document conveyance device 20 is rotatably connected to the scanner body 2 via a hinge (not shown). A document mat 22 (FIG. 2) is provided on the side of the document conveying apparatus 20 facing the scanner body 2.
In the scanner body 2, reference numeral 4 denotes a second original glass as a second transparent member, and the original placed on the second original glass 4 is pressed by the original mat 22 when the original conveying device 20 is closed. The surface to be read is in close contact with the second original glass 4. The document placed on the second document glass 4 is indicated by a symbol M2 in FIG. 8 and thereafter.

In the present embodiment, the scanner 1 is a flatbed scanner as an example, and as shown in FIG. 3, the reading unit 5 movable with respect to the first original glass 3 and the second original glass 4 is the first original glass 3. , And is provided below the second original glass 4. The document placed on the second document glass 4 is read by the movement of the reading unit 5.
In the first to third embodiments which will be described later with reference to FIG. 8 and subsequent figures, the second original glass 4 is indicated by reference numerals 4A, 4B and 4C, and the reading unit 5 is indicated by reference numeral 5A (first , 2nd Embodiment), and the code | symbol 5B (3rd Embodiment), respectively.

  On the other hand, in the scanner body 2, a first original glass 3 as a first transparent member is juxtaposed to the second original glass 4. The first document glass 3 is a glass positioned between a reading unit 5 described later and the document M1 when reading a document conveyed to a reading position by the document conveying device 20. In the first to third embodiments which will be described later with reference to FIG. 8 and the subsequent drawings, the first original glass 3 is indicated by reference numerals 3A, 3B and 3C, respectively.

  In the present embodiment, although the first original glass 3 and the second original glass 4 are both formed of a glass material, the first original glass 3 has an elongated shape compared to the second original glass 4. Therefore, both the first original glass 3 and the second original glass 4 or at least the first original glass 3 may be formed of tempered glass.

The reading unit 5 as document reading means is configured as an optical unit that emits light toward the first document glass 3 and the second document glass 4 and receives the reflected light to read information of the document. In the embodiment, it is configured as an optical unit of a contact image sensor type.
The more detailed structure of the reading unit 5 will be described later.

The reading unit 5 extends in the main scanning direction (x direction) and is provided on the carriage 7 movable in the sub scanning direction (y direction). The carriage 7 receives the power of a motor (not shown) and moves in the sub scanning direction while being guided by a guide member 8 extended in the sub scanning direction.
When reading a document placed on the second document glass 4, the reading unit 5 performs reading while moving in the sub-scanning direction. On the other hand, when reading a document conveyed by the document conveyance device 20, the reading unit 5 is stopped below the first document glass 3 (the state of FIG. 3), and the document reading is performed while maintaining the stopped state.

Subsequently, the document conveyance path in the document conveyance device 20 will be described with reference to FIGS. 3 and 4 and other drawings as appropriate. The broken line indicated by the symbol e in FIGS. 3 and 4 indicates the passage locus of the document M1 conveyed in the document conveying device 20.
The feeding tray 21 capable of setting a plurality of documents M1 has a posture (raising posture) in which the topmost document M1 is in contact with the feeding roller 24 by an elevating mechanism constituted by a link mechanism and a motor (not shown). It is possible to switch between the posture for retreating from the feeding roller 24 (the lowering posture).

The feed roller 24 provided above the leading end (the leading end in the delivery direction) of the feeding tray 21 is driven by a motor (not shown). The outer peripheral surface of the feed roller 24 is formed of a high friction material (rubber).
The feeding roller 24 is provided so as to be vertically displaceable, and is lowered when the feeding tray 21 is lowered (solid line), and when the feeding tray 21 is raised, the reference numeral 24 'and the two-dot chain line are made by the document M1. It is pushed up as shown by.
Then, the feed roller 24 is rotationally driven in a state where the feed tray 21 and the feed roller 24 are both raised, and the uppermost original M1 is sent out.

  On the downstream side of the feed roller 24, a retard roller given a predetermined rotational resistance that nips the document between the separation roller 26 driven in the forward direction by a motor (not shown) and the separation roller 26. The roller 25 and the roller 25 are disposed to face each other. The document M1 sent out by the feed roller 24 is conveyed in a state of being nipped by the separation roller 26 and the retard roller 25, and double feeding of the document M1 and subsequent documents is prevented.

Conveying roller pairs 27, 28, 29, 30, 31 are provided on the document conveyance path downstream of the separation roller 26 and the retard roller 25. The document M1 is conveyed along the conveyance path by the plurality of conveyance roller pairs. Ru. In particular, the document conveyance path from the conveyance roller pair 27 to the conveyance roller pair 29 is a curved reversal route in which the document M1 is curved and reversed.
Reference numeral 32 denotes a discharge roller pair, and the discharge roller pair 32 discharges the read document M 1 to the discharge tray 33.

The rollers of at least one side of the transport roller pairs 27 to 31 and the discharge roller pair 32 are rotationally driven by a motor (not shown), and the rollers of the other side are driven to rotate.
In particular, for the transport roller pair 29, reference numeral 29a is a drive roller, and reference numeral 29b is a driven roller. Moreover, about the conveyance roller pair 30, code | symbol 30a is a drive roller and code | symbol 30b is a driven roller.

  Between the transport roller pair 29 and the transport roller pair 30, the document M 1 reaches a position facing the first document glass 3. At this position, the reading unit 5 is stopped, and scanning by the reading unit 5 is performed using the conveyance operation of the document M1.

  Further, in order to read both sides of the document M1, a reading unit 6 is further provided downstream of the conveyance roller pair 30. This reading unit 6 is similar to the reading unit 5 described above in that it is configured as an optical unit that emits light toward the document and receives the reflected light to read information of the document. However, only the document M1 conveyed using the document conveyance device 20 is fixedly provided.

The above is the configuration of the document conveyance device 20 provided in the scanner 1, and the configuration of the scanner 1 will be further described below.
In FIG. 4, reference numeral 39 denotes a sheet material. The sheet material 39 forms a gap of size s (FIG. 8) between the original M1 and the first original glass 3 so that the original M1 conveyed by the original conveying device 20 does not contact the first original glass 3. . The thickness (gap s) of the sheet material 39 can be set to about 0.1 to 0.7 mm (for example, 0.5 mm).

  In this manner, a gap s (FIG. 8) is formed between the document M1 and the first document glass 3 by the sheet material 39, whereby the document M1 being conveyed is scratched on the glass surface of the first document glass 3. It is possible to avoid the problem that foreign matter such as paper dust, glue or the like adhering to the document M1 adheres to the glass surface to cause a reading defect.

  The sheet material 39 is attached to the first original glass 3 in the present embodiment. However, the present invention is not limited to this. For example, the sheet 39 may be provided on the side of the original conveying device 20, and the sheet 39 may be pressed against the first original glass 3 when the original conveying device 20 is closed. .

The gap s between the document M1 and the first document glass 3 tends to vary as it is separated from the sheet material 39. Therefore, when reading the document M1 conveyed by the document conveyance device 20, in order to obtain a good reading result, the reading position by the reading unit 5 is preferably a position as shown in FIG. However, in this case, the sheet material 39 may affect the reading result by the reading unit 5. Therefore, the sheet material 39 is preferably formed of a material having high light transmittance (transparent or translucent).
Further, it is preferable that the sheet material 39 be formed of a low friction material so that the sheet material 39 exerts no load on the conveyance of the document M1 as much as possible.

  The sheet material 39 may be charged by the conveyance of the document M1 while being in contact with the sheet material 39. In order to prevent such charging, the sheet material 39 may be formed of a metal material and the sheet material 39 may be grounded.

Further, the document conveyance speed by the conveyance roller pair 30 on the downstream side with respect to the reading position is made higher than the document conveyance speed by the conveyance roller pair 29 on the upstream side with respect to the reading position so that the document M1 reliably floats up from the first document glass 3 It may be set to high speed.
In FIG. 4, reference numeral 38 denotes a guide member which defines the floating position of the document M1.

  Since it is difficult to obtain the document floating effect by the sheet material 39 at the front end or the rear end of the document, the reading data of the front end region or the rear end region of the document may be processed by, for example, emphasizing an edge by software. Alternatively, the data itself may be discarded outside the readable area.

  Subsequently, in FIG. 2 and FIG. 4, reference numeral 35 denotes a frame member provided between the first original glass 3 and the second original glass 4. A guide slope 36 is formed to guide the vehicle. In FIG. 4, reference numeral 34 denotes a freely rotatable guide roller provided at a position facing the guide slope 36.

In addition, a movement assisting portion 37 is formed on the frame member 35 so as to protrude toward the reading portion 5 side. The movement assisting unit 37 has an inverted trapezoidal shape, and when the reading unit 5 moves from the first document glass 3 to the second document glass 4 or in the opposite direction, the reading unit 5 is moved to the first document By separating from the gap between the glass 3 and the second original glass 4, hooking of the reading unit 5 to the glass edge is suppressed.
The shape (the angle of the slope, etc.) of the movement assisting portion 37 can be appropriately changed in accordance with the step between the first original glass 3 and the second original glass 4 or the like.

  Subsequently, the configuration of the reading unit 5 will be described with reference to FIGS. 4 to 7. The reading unit 5 includes a substrate 10 having a shape extending in the main scanning direction, a lens array 11, and light guides 12 and 12 in a frame 15 having a shape extending in the main scanning direction. A sensor (not shown) (for example, a CMOS sensor) is provided on the substrate 10, and a lens array 11 as a reading lens is disposed opposite to the sensor at an interval A (FIG. 7). Light from a light source (for example, an LED) (not shown) is incident on the light guides 12 and 12 so as to be irradiated from the light guides 12 and 12 to the document. The irradiated light is reflected by the original, and the reflected light is irradiated to the sensor on the substrate 10 through the lens array 11, and the reading is performed.

  Parameters such as thickness of each original glass are set such that the distance A between the lower surface of the lens array 11 and the sensor and the distance B between the upper surface of the lens array 11 and the original reading surface (FIG. 7) are the same. (Details will be described later).

  Subsequently, spacer members 13 are provided at both ends in the longitudinal direction of the frame 15. Protrusions 14A and 14A are formed at predetermined positions in the sub scanning direction (y direction) at positions facing the first original glass 3 and the second original glass 4 in the spacer member 13. On the other hand, in the carriage 7, the reading unit 5 is biased toward the first document glass 3 and the second document glass 4 by biasing means (for example, a spring) not shown.

Then, the reading unit 5 is configured to move while the projections 14A and 14A are in contact with the lower side (or a sheet material described later) of the first original glass 3 or the second original glass 4 by the biasing force. In other words, the protrusions 14A, 14A define the distance B between the upper surface of the lens array 11 and the document. The protrusions 14A, 14A constitute a sliding surface that slides when moving along the first original glass 3 and the second original glass 4.
The distance d1 (FIG. 8) between the upper surface of the lens array 11 and the first original glass 3 or the distance d2 (FIG. 8) between the upper surface of the lens array 11 and the second original glass 4 In order to avoid contact with the lower side of the original glass, for example, it is preferable to secure 0.5 mm or more.

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A first embodiment of the present invention will be described with reference to FIG. In FIG. 4, hatching is appropriately omitted for simplification of the drawing, and only constituent elements necessary for explanation are shown as much as possible, and other constituent elements are not illustrated. Further, in FIG. 8, for convenience of explanation, the reading unit 5A is located for both the case where the reading unit 5A is located below the first original glass 3A and the case where the reading unit 5A is located below the second original glass 4A. Is indicated by a solid line. The features of these figures are the same in FIG. 9 and later, which will be described later.

  In the present embodiment, the thickness t1 of the first original glass 3A and the thickness t2 of the second original glass 4A are different, and both original glasses are provided so that the lower surface is flush. Therefore, in the present embodiment, the distance d1 between the upper surface of the lens array 11 and the lower surface of the first original glass 3A and the distance d2 between the upper surface of the lens array 11 and the lower surface of the first original glass 3A are the same. is there. The thickness t1 of the first original glass 3A can be set, for example, to about 2.8 mm, and the thickness t2 of the second original glass 4A can be set, for example, to about 3.2 mm.

  The refractive index of the first original glass 3A is n1, and the refractive index of the second original glass 4A is n2. In the present embodiment, since the first original glass 3A and the second original glass 4A are the same glass, n1 = n2.

And in this embodiment, the value obtained by [s + t1 / n1 + d1] and the value obtained by [t2 / n2 + d2] are set to be the same or almost equal.
That is, in paraxial optics, the optical path length when light is incident perpendicularly to a plane-parallel plate of thickness t and refractive index n is equivalent to the optical path length t / n in air. According to this, in the present embodiment, the optical path length [s + t1 / n1 + d1] at the time of document reading by the document conveyance device 20 and the optical path length [t2 / n2 + d2] at the time of reading by the movement of the reading unit 5A become equal or almost equal. Configured. Here, "approximately equal" means including a state in which a slight error occurs due to a deviation in part accuracy or assembly accuracy (the same applies to the following embodiments).

  In other words, in the present embodiment, the distance (s + t1) from the projections 14A and 14A constituting the sliding surface with the first original glass 3A and the second original glass 4A to the original M1 separated from the first original glass 3A. And the distance (t2) from the protrusions 14A and 14A to the upper surface (original placement surface) of the second original glass 4A are in focus on both the originals M1 and M2 within the depth of field of the reading unit 5A. It is aligned as.

  Thereby, even if the document M1 is floated from the first document glass 3A by the sheet material 39 at the time of reading the document by the document conveyance device 20, the focus is the same as when reading the document M2 placed on the second document glass 4A, It is possible to appropriately perform reading by automatic document conveyance.

Further, in the present embodiment, the surface (lower surface) opposite to the reading unit 5A in the first document glass 3A and the surface (lower surface) opposite to the reading unit 5A in the second document glass 4A are flush. When the section 5A moves from the first original glass 3A to the second original glass 4A or vice versa, the reading section 5A can move smoothly because there is no step.
The present invention is not limited to this. Conversely, the upper surface of the first original glass 3A may be flush with the upper surface of the second original glass 4A.

  In the present embodiment, since the thickness t1 of the first original glass 3A and the thickness t2 of the second original glass 4A are different, the case of reading via the first original glass 3A due to the difference in glass thickness and The reading density and the like may differ, for example, from the case of reading through the second original glass 4A. Further, since the first original glass 3A reads the original M1 in a floating state, the reading density and the like may be different when reading through the first original glass 3A and when reading through the second original glass 4A. is there. Therefore, these differences may be corrected by software processing as appropriate.

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The first embodiment will be described with reference to FIG.
In the present embodiment, the thickness t1 of the first original glass 3B and the thickness t2 of the second original glass 4B are the same, and both original glasses are provided so that the upper surface and the lower surface are flush. And in this embodiment, the sheet material 40 of thickness g is stuck on the side of the 2nd manuscript glass 4B.

The sheet material 40 is attached only to the position where the protrusions 14A and 14A of the reading unit 5A contact in the main scanning direction (x direction), and is not attached to the part facing the lens array 11. As a result, the sheet material 40 does not disturb reading of the document through the second document glass 4A.
As described above, in the present embodiment, when the protrusions 14A and 14A, which are a part of the reading unit 5A, are in contact with the sheet material 40, the thickness g of the sheet material 40 constitutes a part of the gap d2.

  Also in this embodiment, as in the first embodiment described above, the value obtained by [s + t1 / n1 + d1] and the value obtained by [t2 (= t1) / n2 + d2] are set to be the same or substantially the same. There is.

  In other words, also in the present embodiment, the distance (s + t1) from the projections 14A and 14A constituting the sliding surfaces with the first original glass 3B and the second original glass 4B to the original M1 separated from the first original glass 3B. And the distance (t2 + g) from the projections 14A and 14A to the upper surface (original placement surface) of the second original glass 4B are in focus on both the originals M1 and M2 within the depth of field of the reading unit 5A. It is aligned as.

  Thereby, even if the document M1 is floated from the first document glass 3B by the sheet material 39 at the time of reading the document by the document conveyance device 20, the focus is the same as when reading the document M2 placed on the second document glass 4B, It is possible to appropriately perform reading by automatic document conveyance.

  In the present embodiment, the thickness t1 of the first original glass 3B is equal to the thickness t2 of the second original glass 4B, and the refractive index n1 of the first original glass 3B and the refractive index of the second original glass 4B. and n2 are equal. That is, the same material can be used for the first original glass 3B and the second original glass 4B, and the cost of the apparatus can be reduced.

  Although the thickness t1 of the first original glass 3B and the thickness t2 of the second original glass 4B are equal in this embodiment, the thickness g of the sheet material 40 can be adjusted even if the thicknesses are different. And the distance d2 can be easily adjusted.

  In the present embodiment, the sheet material 40 can be made of, for example, a resin-made sheet material, and may be formed of a glass material. In this case, wear of the sheet material 40 due to sliding with the reading unit 5A (protrusions 14 and 14) can be suppressed, and sliding property on the first original glass 3B side and sliding on the second original glass 4B glass side It is possible to equalize the characteristics, and ensure a good moving operation of the reading unit 5A.

■ ■ ■ 3rd embodiment ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
A third embodiment will be described with reference to FIGS. 10 to 12.
In the present embodiment, the thickness t1 of the first original glass 3C and the thickness t2 of the second original glass 4C are the same, and both original glasses are provided so that the upper surface and the lower surface are flush. Then, in the present embodiment, the protrusions 14B and 14C having different amounts of protrusion are formed in the reading portion 5B, and the protrusions 14B having a relatively small amount of protrusion abut the first original glass 3C, and the amount of protrusion is relatively large. The large number of projections 14C are configured to abut on the second original glass 4C.

  The projection 14B as the "first projection" is provided relatively inward of the projection 14C as the "second projection" in the main scanning direction (x direction) as shown in FIGS. . On the other hand, as shown in FIG. 11, the length of the first original glass 3C in the main scanning direction (x direction) is slightly shorter than that of the second original glass 4C. As a result, when the reading unit 5B faces the first original glass 3C, the protrusion 14B abuts on the first original glass 3C to define the distance d1. Further, when the reading unit 5B faces the second original glass 4C, the projection 14C abuts on the second original glass 4C to define the distance d2.

  Also in this embodiment, as in the first and second embodiments described above, the value obtained by [s + t1 / n1 + d1] and the value obtained by [t2 (= t1) / n2 + d2] are the same or substantially equal. It is set. Thereby, even if the document M1 is floated from the first document glass 3C by the sheet material 39 at the time of reading the document by the document conveyance device 20, the focus is the same as when reading the document M2 placed on the second document glass 4C, It is possible to appropriately perform reading by automatic document conveyance.

And in this embodiment, since protrusion 14B, 14C is a structure which each prescribes | regulates space | interval d1, d2, structure space | interval d1, d2 can be simplified and it can adjust to low cost.
In the present embodiment, although the thickness t1 of the first original glass 3C and the thickness t2 of the second original glass 4C are equal to each other, the protrusion amounts of the protrusions 14B and 14C may be adjusted even if the thicknesses are different. Thus, the intervals d1 and d2 can be easily adjusted.

DESCRIPTION OF SYMBOLS 1 scanner 2 scanner main body 3A, 3B, 3C 1st original glass 4A, 4B, 4C 2nd original glass 5A, 5B reading unit 6 reading unit 7 carriage 8 guide member 10 substrate 11 lens array , 12 light guides, 13 spacer members, 14A, 14B, 14C protrusions, 15 frames, 20 document conveying devices, 21 feeding trays, 22 document mats, 23A, 23B edge guides, 24 feeding rollers, 25 retard rollers, 26 separation Rollers, 27 to 31 transport roller pairs, 32 discharge roller pairs, 33 discharge trays, 34 guide rollers, 35 frame members, 36 guide slopes, 37 movement assisting portions, 38 guide members, 39 sheet materials, 40 sheet materials, M1, M2 Manuscript

Claims (9)

Original conveying means for conveying an original to an original reading position;
A first transparent member provided at the document reading position;
A second transparent member on which a document is placed, which is juxtaposed to the first transparent member;
Reading means provided movably along the first transparent member and the second transparent member, and reading a document through the first transparent member and the second transparent member;
A gap is formed between the document and the first transparent member at the document reading position,
The size of the gap is s,
The refractive index of the first transparent member is n1,
The thickness of the first transparent member is t1,
The refractive index of the second transparent member is n2,
The thickness of the second transparent member is t2,
The distance between the upper surface of the reading lens provided in the reading means and the first transparent member is d1,
When the distance between the upper surface of the reading lens and the second transparent member is d2,
a value obtained by [s + t1 / n1 + d1],
and a value obtained by [t2 / n2 + d2], but almost rather equal or the same,
The reading unit is provided with a first protrusion and a second protrusion protruding with respect to the first transparent member and the second transparent member.
When the reading unit is at a position facing the first transparent member, only the first projecting portion of the first and second projecting portions contacts the first transparent member, thereby the distance d1. Is defined,
When the reading unit is at a position facing the second transparent member, only the second projecting portion of the first and second projecting portions contacts the second transparent member, thereby the distance d2 With the configuration specified
An image reading apparatus characterized in that. Original conveying means for conveying an original to an original reading position;
A first transparent member provided at the document reading position;
A second transparent member on which a document is placed, which is juxtaposed to the first transparent member;
Reading means provided movably along the first transparent member and the second transparent member, and reading a document through the first transparent member and the second transparent member;
A gap is formed between the document and the first transparent member at the document reading position,
The size of the gap is s,
The refractive index of the first transparent member is n1,
The thickness of the first transparent member is t1,
The refractive index of the second transparent member is n2,
The thickness of the second transparent member is t2,
The distance between the upper surface of the reading lens provided in the reading means and the first transparent member is d1,
When the distance between the upper surface of the reading lens and the second transparent member is d2,
a value obtained by [s + t1 / n1 + d1],
The value obtained by [t2 / n2 + d2] is equal to or approximately equal to
  In the second transparent member, a sheet material having a thickness g is attached to the side facing the reading means, and a part of the distance d2 is the thickness g when a part of the reading means is in contact with the sheet material. Configure,
  An image reading apparatus characterized in that. The image reading apparatus according to any one of claims 1 and 2 , wherein the distance d1 and the distance d2 are the same or substantially equal,
The thickness t2 is set in accordance with the gap s + the thickness t1.
An image reading apparatus characterized in that. The image reading apparatus according to any one of claims 1 or 2 , wherein the thickness t1 and the thickness t2 are the same or substantially equal, and the refractive index n1 and the refractive index n2 are the same Almost equal,
An image reading apparatus characterized in that. 2. The image reading apparatus according to claim 1, wherein a sheet material having a thickness g is attached to a side of the second transparent member facing the reading means, and a part of the reading means is in contact with the sheet material. The thickness g constitutes a part of the distance d2;
An image reading apparatus characterized in that. The image reading apparatus according to any one of claims 1 to 5 , wherein a surface of the first transparent member facing the reading unit, and a surface of the second transparent member facing the reading unit, Is the same,
An image reading apparatus characterized in that. The image reading apparatus according to any one of claims 2 to 6 , wherein the reading unit includes a first protrusion and a second protrusion protruding with respect to the first transparent member and the second transparent member. Department is provided,
When the reading unit is at a position facing the first transparent member, only the first projecting portion of the first and second projecting portions contacts the first transparent member, thereby the distance d1. Is defined,
When the reading unit is at a position facing the second transparent member, only the second projecting portion of the first and second projecting portions contacts the second transparent member, thereby the distance d2 With the configuration specified
An image reading apparatus characterized in that. Original conveying means for conveying an original to an original reading position;
A first transparent member provided at the document reading position;
A second transparent member on which a document is placed, which is juxtaposed to the first transparent member;
Reading means provided movably along the first transparent member and the second transparent member, and reading a document through the first transparent member and the second transparent member;
A gap is formed between the document and the first transparent member at the document reading position,
The reading unit has a sliding surface that slides when moving along the first transparent member and the second transparent member.
From the sliding surface, a first optical path length to the original spaced from the first transparent member, from the sliding surface, the second second optical path length to the original placing surface of the transparent member is the same or Configured to be approximately equal,
In the second transparent member, a sheet material is attached to the side facing the reading means, and when a part of the reading means contacts the sheet material, a part of the second optical path length is a thickness of the sheet material Configured by
An image reading apparatus characterized in that. Original conveying means for conveying an original to an original reading position;
A first transparent member provided at the document reading position;
A second transparent member on which a document is placed, which is juxtaposed to the first transparent member;
Reading means provided movably along the first transparent member and the second transparent member, and reading a document through the first transparent member and the second transparent member;
A gap is formed between the document and the first transparent member at the document reading position,
The reading unit has a sliding surface that slides when moving along the first transparent member and the second transparent member.
Whether the first optical path length from the sliding surface to the document separated from the first transparent member and the second optical path length from the sliding surface to the document mounting surface of the second transparent member are the same Configured to be approximately equal,
  The reading unit is provided with a first protrusion and a second protrusion protruding with respect to the first transparent member and the second transparent member.
When the reading unit is in a position facing the first transparent member, only the first projecting portion of the first and second projecting portions contacts the first transparent member. The optical path length is specified,
When the reading unit is at a position facing the second transparent member, only the second protrusion of the first and second protrusions contacts the second transparent member. With a configuration in which the optical path length is defined,
An image reading apparatus characterized in that.

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