JP2009157218A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent read error due to positional displacement of a document in a simple structure by setting a thin document and a thick document at document positions when the documents are set on a platen. <P>SOLUTION: A positioning member for regulating at least one side of a document mounted on the platen comprises a first reference surface for regulating the edge of a document of a thickness of a predetermined thickness or smaller, an overhang section for covering the edge of this document from the upside, and a second reference surface for butting and regulating the edge of a document of a thickness of the predetermined thickness or larger inside the overhang section. The document of the thickness of the predetermined thickness or smaller is inserted between the overhang section and the platen top surface and is positioned by the first reference surface, the document of the thickness of the predetermined thickness or larger is positioned by the second reference surface, and a set reference detection sensor for detecting the existence of the document inserted in the overhang section is disposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that optically reads an image on a document sheet, such as a copying machine, a facsimile machine, and a scanner, and relates to an improvement of a document setting mechanism that places and sets a document on a platen glass.

  In general, this type of image reading apparatus is widely used in various optical instruments as an apparatus for placing and setting a document on a platen and optically reading the document image with a photoelectric conversion element. The platen is composed of a transparent glass plate or the like on which a document sheet is set stationary.

  Conventionally, when a document is placed and set on this type of platen, a reference plate for forming a step is provided on the periphery of the platen in order to accurately position the document. The reference plate is provided with marks such as a document size position, a vertical and horizontal posture, and is configured as a scale of a placed document. Further, a platen cover is attached to the platen so as to be freely opened and closed, and a document set along the scale is covered with the platen cover to read an image.

  As described above, in the conventionally known document setting mechanism, there is a problem that the document sheet is displaced when the document sheet placed on the platen is covered with the platen cover. For example, when a thin sheet original is set on the platen and the platen cover is covered with force, the problem is that the original sheet is scattered outside the platen due to the wind pressure, or the original sheet is inclined and set. ing.

Therefore, Patent Document 1 proposes a document pressing device that holds a document placed on a platen glass with a clip-shaped holder. According to the publication, when the document is a thin sheet, the platen cover is closed with the clip edge holding the sheet edge nipped, and when the book is a thick book, it is abutted against the leading edge of the clip holder. And positioning is disclosed.
Japanese Patent Laid-Open No. 9-163048 (FIG. 2)

  As described above, it is widely known to provide a scale that guides an accurate position when an original is set on a platen. It is also known from the above-mentioned Patent Document 1 that a clip mechanism for holding a thin sheet document is provided on the scale member.

  As described above, when the mechanism of Patent Document 1 is used to hold the nip so that the original sheet placed on the platen is not displaced by the subsequent closing operation of the platen cover, it cannot be held by this nip mechanism. The book document must be set inside the nip mechanism. Accordingly, on the platen, the original is set at different positions for the area where the thin original (sheet original) is set and the area where the thick original (book original) is set.

  The above-mentioned patent document 1 does not disclose or suggest how to set a reading area of a document having a different set position as described above. However, in this publication, the nip position is set as a reference for a transparent original, and the inner scale is set for a reflective original. Images are individually read in the transparent original reading mode and the reflective original reading mode. For this reason, the same original (for example, a reflective original) is not set in the first and second different areas. Therefore, it is adopted as an apparatus configuration that does not need to determine in which area the same document is set.

  However, if a device configuration in which a thin original (sheet original) is set at the nip position and a thick original (book original) is set at a scale position different from the nip position in the same reading mode such as transmission or reflection is set on the platen. It is necessary to determine in which position the original is set.

  Therefore, the present inventor has come up with the idea that a thin document is positioned by inserting one or two sides into a small gap in the same reading mode, and a thick document is positioned against the edge. It has been determined that the document size or the effective reading area is discriminated by detecting the position of the document.

The present invention provides an image reading apparatus capable of preventing reading errors due to misalignment of a document with a simple structure by setting a thin document and a thick document at different positions when the document is set on a platen. It is an issue.
It is another object of the present invention to provide an image reading apparatus capable of automatically determining a document set at a first and second different position on a platen and accurately setting an image reading region after the document is set. It is said.

  In order to achieve the above object, the present invention provides a positioning member for regulating at least one side of a document placed on a platen, a first reference surface for regulating a document edge of a predetermined thickness or less, and an edge of the document. An overhang portion that covers from above and a second reference surface that abuts and regulates the document edge of a predetermined thickness or more inside the overhang portion are provided. A document having a predetermined thickness or less is inserted between the overhang portion and the upper surface of the platen and positioned on the first reference surface, and a document having a predetermined thickness or more is positioned on the second reference surface. And a set reference detection sensor for detecting the presence or absence of a document inserted into the overhang portion. The specific configuration will be described below.

  A platen on which the document is placed, a positioning member that is disposed on a side edge of the platen and regulates at least one side of the document, and an optical reading unit that reads the document placed on the platen. The positioning member includes a first reference surface that abuts and regulates an edge of the document having a predetermined thickness or less, an overhang portion that covers the edge of the document from above, and an end of the document that is provided in the overhang portion and has a predetermined thickness or more. A document having a thickness of not more than a predetermined thickness is inserted between the overhang portion and the upper surface of the platen, and positioned on the first reference surface. The document is configured to be positioned on the second reference surface, and includes a set reference detection sensor that detects the presence or absence of the document inserted between the overhang portion and the upper surface of the platen.

  The overhang portion is provided with a detection surface of the set reference detection sensor, and the detection surface is colored with a light absorption rate different from that of a document such as black.

  A size detection sensor that detects an edge of the document placed on the platen; and a size determination unit that determines a document size based on a signal from the size detection sensor. The size determination unit includes the size detection sensor and the size detection sensor. Based on the detection signal from the set reference detection sensor, the size of the document and / or the effective reading area of the image reading means is determined.

  The size detection sensor includes a first sensor for detecting the other end edge of the document positioned on the first reference surface and a second sensor for detecting the other end edge of the document positioned on the second reference surface. The size determination means selects one of the first sensor and the second sensor based on a detection signal from the set reference detection sensor to determine the size of the document and / or the effective reading area of the image reading means. To do.

  The optical reading means includes a line sensor that reads a document placed on the platen in line order, and a carriage that carries the line sensor and moves in the sub-scanning direction. The first sensor and the second sensor Are arranged at a distance in the sub-scanning direction of the optical reading means.

  The platen is provided with an openable / closable platen cover for covering the placed document, and the platen cover is provided with an open / close sensor for detecting an open / closed state. The carriage is controlled to be positioned at a read start position set in advance by signals from the open / close sensor and the set reference detection sensor.

  The present invention provides a positioning member that restricts at least one side of a document placed on a platen, a first reference surface that regulates an edge of the document having a predetermined thickness or less, and an overhang that covers the edge of the document from above. A second reference surface that regulates an edge of the document having a predetermined thickness or more inside the overhang portion, and a document having a predetermined thickness or less is inserted into the overhang portion and positioned on the first reference surface. The document having a thickness greater than or equal to the thickness is configured to be positioned on the second reference surface. In this case, since the set reference detection sensor for detecting the presence or absence of the document inserted into the overhang portion is provided, the following effects can be obtained. .

  A thin original such as curled paper is inserted between the platen top surface and the overhang, and the edge of the thin original is positioned on the first reference surface, so that there is no risk that the original will be misaligned when the set original is covered with the platen cover. Image reading is possible. In addition, when a thick original such as a book original is positioned on the second reference plane disposed inside the overhang portion (the flange of the overhang portion or the inside thereof), whether the original is positioned on the first or second reference plane It is possible to accurately set the subsequent image reading area by detecting whether or not by the set reference detection sensor.

  Furthermore, the present invention positions a size detection sensor for detecting the edge of the document placed on the platen on the first sensor and the second reference surface for detecting the other edge of the document positioned on the first reference surface. And a second sensor for detecting the other end edge of the original, and configured to determine the size of the original and / or the effective reading area of the image reading means based on the detection signal of the set reference detection sensor. Thus, the present invention has a remarkable effect such that the size of the document or the effective reading area by the optical reading means can be determined with a simple structure.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 is a perspective explanatory view showing the entire configuration of an image reading apparatus according to the present invention, and FIG. 2 is a longitudinal explanatory view thereof. FIG. 3 is an explanatory view of a cross section of a main part for feeding a document sheet to the platen. 4 shows a state where a sheet document is set on the document placement platen, and FIG. 5 shows a state where a book document is set on the document placement platen.

  The image reading apparatus shown in FIG. 1 includes a scanner unit A and a document transport unit B. The document transport unit B is installed on the scanner unit A. In the scanner unit A, as shown in the drawing, a document traveling platen 2 (hereinafter referred to as “first platen”) and a document fixing platen 3 (hereinafter referred to as “second platen”) are arranged in parallel on the upper surface of the outer casing 1 (housing). Has been placed. The document transport unit B includes a feeder mechanism 4 that feeds a document sheet to the first platen 2 and a platen cover 5 that covers the document on the second platen. Has been. Each configuration will be described in detail below.

[Configuration of scanner unit]
The scanner unit A includes the first platen 2 and the second platen 3 described above in the exterior casing 1, and an image reading mechanism is built in the casing. The image reading mechanism shown in FIG. 2 will be described. In the casing 1, a carriage 6 that reciprocates along the first and second platens 2, 3, a condenser lens 7, and a photoelectric conversion element 8 are arranged. . The illustrated apparatus irradiates light on a document on a platen from a light source lamp 9 mounted on a carriage 6, guides the reflected light to a condenser lens 7 by a plurality of mirrors 10, and electrically reads the light by a photoelectric conversion element 8. The system is shown. Therefore, the carriage 6 is supported by the guide rail 12 and is configured to reciprocate along the second platen 3. Accordingly, the carriage 6 scans the document set on the second platen while moving along the second platen 3 and reads an image by the photoelectric conversion element (line sensor) 8. At the same time, the carriage 6 is configured to move from the second platen 3 directly below the first platen 2 and to read an image of a document moving on the platen 2 at a predetermined speed while still in this position.

  Although the illustrated reading optical system is a reduction optical system that moves the carriage 6 on which the light source is mounted and fixes the condenser lens 7 and the photoelectric conversion element 8 to the apparatus frame, the photoelectric conversion element 8 is also used together with the light source. Needless to say, the optical system may be configured with a 1 × optical system that moves while mounted on the carriage. In this case, a contact sensor in which a light source, a lens, and a photoelectric conversion element are integrated may be used.

[Configuration of Document Feed Unit]
As shown in FIG. 2, the document conveying unit B is disposed above the first and second platens 2 and 3 so as to cover the first and second platens 2 and 3. A guide member 21 and a carry-out roller 22 for scooping up an original sheet from one platen 2 are provided. Further, on the upstream side of the read roller 20, a paper feed stacker 23 for stacking and storing original sheets, a paper feed roller 24 for stacking and feeding the sheets one by one on the paper feed stacker, and the separate feed. A registration roller pair 25 for correcting the skew of the front end of the sheet is disposed. 26 is a paper feed path for guiding a document sheet from the paper feed stacker 23 to the first platen 2, and S1 is a lead sensor for detecting the leading edge of the document reaching the platen.

  In the illustrated apparatus, a backup roller 27 for guiding a document sheet is disposed above the first platen 2. The backup roller 27 rotates at the same peripheral speed as the lead roller 20 to fit the original sheet on the first platen. A backup guide may be arranged above the platen without providing the backup roller 27.

  A paper discharge roller 28 and a paper discharge stacker 29 are disposed on the downstream side of the carry-out roller 22. As shown in FIG. 2, the paper discharge stacker 29 is arranged vertically below the paper feed stacker 23, and a platen cover 5 for pressing and supporting the original sheet on the second platen 3 is provided at the bottom. Yes.

  The document transport unit B configured as described above is installed on the upper housing (exterior casing) 1 of the scanner unit A so as to be freely opened and closed by a hinge member 1h (see FIG. 1). The document sheet is placed and set with the second platen 3 opened, and the document is covered with the platen cover 5 of the transport unit B. On the other hand, when the transport unit B is opened and closed, the frame of the transport unit B contacts the first platen 2 so that the distance (original transport gap) between the first platen 2 and the backup roller 27 (or backup guide) does not change. Positioning protrusions (stopper members; not shown) are provided.

[Configuration of the second platen]
Therefore, the present invention is characterized in that the second platen 3 described above is configured as follows.
The second platen 3 is made of a transparent plate such as glass, and is configured to place a sheet document or a book document on the upper surface thereof. In this case, there are various sheet originals such as thin paper sheets that are easily curled, plastic sheets such as OHP, and thick cardboard, and book originals vary from a thick booklet bundle to a thin booklet bundle.

[Configuration of positioning member]
Therefore, the second platen 3 is provided with a positioning member 50 for setting the document at the correct position in the correct posture. The positioning member 50 is disposed on at least one side of the second platen 3 and is formed with a stepped surface that abuts and regulates the edge of the document. The illustrated apparatus is provided on two sides of the second platen 3 on the X side and the Y side shown in FIG.

  The above-described positioning member 50 includes a reference surface 51 shown in FIG. 4 that restricts the X side and the Y side that are orthogonal and adjacent to each other. In the present invention, the reference surface 51 is disposed at a different position (offset) between the first reference surface 51a and the second reference surface 51b, and a small gap d is provided between the first reference surface 51a and the platen upper surface 3a. An overhang 52 is provided to cover the edge of the original sheet Sg from above. The gap d is set in advance to the thickness of one original sheet, and is formed so that an original having a predetermined thickness or less is sandwiched between the platen upper surface 3 a and the overhang portion 52.

  The overhang portion 52 is provided so as to protrude from the reference surface 51a to the set surface side so as to cover the edge portion of the document sheet Sg placed on the platen upper surface 3a of the second platen 3 from above. As shown in FIG. 6A, the first reference surface 51 a and the overhang portion 52 formed in a step shape at the edge of the second platen 3 are integrally formed. A distance d is formed between the platen upper surface 3a and a distance L1 overhanging the platen. The interval d is formed such that a document (sheet document) having a predetermined thickness or less that enters in advance enters the overhang portion 52.

  Accordingly, the original sheet Sg set on the second platen 3 is supported by sandwiching the edge portion between the platen upper surface 3a and the overhanging portion 52 lower surface. Accordingly, the overhanging length L1 of the overhang portion 52 is set to a length sufficient to hold and hold the curled sheet or thin paper sheet from above.

  The overhang portion 52 is provided with a second reference surface 51b as shown in FIGS. The second reference surface 51b is constituted by the flange portion of the overhang portion 52 at a position offset from the first reference surface 51a by the distance L1 inside the platen. Then, as shown in FIG. 6B, a document (for example, a book document bg) having a predetermined thickness that cannot be inserted into the gap d is abutted and regulated.

[Configuration of set reference detection sensor]
The overhang portion 52 is provided with a detected surface 52S of a set reference detection sensor St that detects whether or not a document is set in the interval d. The illustrated detection surface 52S is colored black considering that the original sheet is white. Therefore, when the document is set in the overhang portion 52, the set reference detection sensor St sets the document on the first reference surface 51a due to the difference in light absorption characteristics between the detected surface 52S and the document sheet Sg. Detect whether or not.

  In addition to the set reference detection sensor St, the second platen 3 described above includes a size detection sensor SS that detects the document size set on the first reference surface 51a and the second reference surface 51b, and the size detection sensor SS. Size discriminating means 54 for discriminating the document size by a signal from the sensor SS is provided.

  The size detection sensor SS is disposed in the outer casing 1 and is configured by a sensor that detects an edge of a document set on the upper second platen 3. The size detection sensor SS is constituted by a plurality of sensor arrays, for example, so as to detect a document of a predetermined standard size. Therefore, the illustrated one is provided with a first sensor SS1 for detecting the document edge of the second platen 3 in the sub-scanning direction (left and right direction in FIGS. 4 and 5) with the first reference surface 51a as a base point. Similarly, a second sensor SS2 for detecting the document edge from the second reference surface 51b as a base point is disposed.

[Configuration of size discrimination means]
As described above, a document (sheet document Sg shown in FIG. 4) having a predetermined thickness or less is inserted into the second platen 3 between the overhang portion 52 and the platen upper surface 3a and positioned on the first reference surface 51a. Then, the original (book original bg shown in FIG. 5) having a predetermined thickness or more is positioned on the second reference surface 51b. Therefore, the size discriminating means 54 for discriminating the size of the original set on the second platen 3 or the effective reading area ar (see FIG. 7) of the photoelectric conversion element (image reading means) 8 is configured as follows.

  The size discriminating means 54 is configured as follows, for example, by the control CPU of the image reading apparatus, although not shown. The platen cover 5 is provided with an opening / closing sensor 55 for detecting the opening / closing movement in the vicinity of the hinge member 1h as shown in FIG. The open / close sensor 55 detects the state in which the platen cover 5 covers the second platen 3. The control CPU performs (1) reading start position determination, (2) reading end position determination and / or (3) document size determination by the ON signal of the open / close sensor 55 and the ON / OFF signal of the set reference detection sensor St described above. Execute. In other words, the signal indicating that the open / close sensor 55 is turned on by the closing operation of the platen cover 5 is performed, and the reading start position discrimination in (1) is performed by the set reference detection sensor St to position the document on the first reference surface 51a (St = ON) Sometimes, the position of the first reference surface 51a is set as the reading start position. When the document is not positioned on the first reference surface 51a (St = OFF), the second reference surface 51b position is set as the reading start position. FIG. 7 shows the relationship between the reading start position, the reading end position, and the effective reading area ar.

  The reading end position determination (2) is calculated from the state signal of the size detection sensor SS (SS1, SS2) immediately before the platen cover 5 is closed and the signal of the set reference detection sensor St. In this case, when the set reference detection sensor St is “ON”, the reading end position is determined based on the state signal of the first sensor SS1 arranged to detect the length position of the document with the first reference surface 51a as a base point. To do. Further, when the set reference detection sensor St is “OFF”, the reading end position is determined based on the status signal of the second sensor SS2 arranged so as to detect the length position of the document with the second reference surface 51b as a base point. .

  The document size discrimination of (3) is based on the status signal of the first sensor SS1 when the set reference detection sensor St is ON as described above, and the status signal of the second sensor SS2 when the set reference detection sensor St is OFF. The length of the document in the sub-scanning direction is calculated, and the length of the document in the main scanning direction is determined from the output signal of the image reading means 8. Then, the length of the main scanning direction and the length of the sub scanning direction are compared with the standard size stored in the RAM in advance to identify the document size. The document size identified in this way is transferred to the external device together with the read data via the image processing unit.

[Description of action]
Next, an operation of setting an original on the second platen (original fixing platen) 3 and reading an image will be described. First, the user turns on the apparatus power and opens the platen cover 5 in order to set a read document. By this cover opening operation, the open / close sensor 55 is turned OFF, and the cover opening is detected. Next, the user places and sets the original on the second platen 3. At this time, a document having a predetermined thickness or less such as a sheet document Sg is inserted between the platen upper surface 3a and the overhang portion 52, and the end surface of the document is regulated against the first reference surface 51a. In this state, the document curled and curled at the periphery is set to the reference plane in a correct posture with the edge portion regulated by the overhang portion 52. Next, the user closes the platen cover 5. At this time, since the peripheral edge of the sheet document Sg is restricted by the overhang portion 52, the sheet document Sg is set at the correct position and in the correct posture without moving due to the wind pressure when the platen cover 5 is closed.

  Further, an original document having a predetermined thickness or more such as a book original bg is regulated by abutting the edge against the second reference surface 51b. Then, the user closes the platen cover 5. In this case, the book document or the document having a predetermined thickness or more does not move due to the wind pressure when the cover is closed.

  Therefore, the control CPU (not shown) detects the closing operation of the platen cover 5 with the open / close sensor 55 and executes the above-described size detection. Simultaneously with this size detection (the above-described reading start position, end position, etc.), the control CPU moves the carriage 6 to a predetermined start position. This start position is set immediately before the first reference surface 51a, and the start position is set to the same position when the document is positioned on the first reference surface 51a and when the document is positioned on the second reference surface 51b. It may be set or the start position may be varied depending on the reference plane.

  Next, when the user operates the start button, an original image on the platen is read while moving the carriage 6 from the start position at a predetermined speed. For the read image data, the output data from the image reading means 8 between the reading start position and the reading end position is validated and transferred to the image processing section.

  In the present invention, the positioning member 50 is disposed on two orthogonal sides of the second platen 3. However, the positioning member 50 may be configured to restrict the position of only one side of the document. . In the illustrated example, the overhang portion 52 forms a predetermined gap d with the platen upper surface 3a. However, the overhang portion 52 may be formed of an elastic film member (for example, a mylar member). Of course it is good.

1 is an explanatory perspective view illustrating an entire configuration of an image reading apparatus according to the present invention. FIG. 2 is a longitudinal explanatory view of the apparatus of FIG. 1. Sectional explanatory drawing of the principal part which feeds an original sheet to a platen. FIG. 3 is an explanatory diagram of a state where a sheet document is set on a platen in the apparatus of FIG. 2. FIG. 3 is an explanatory diagram of a state in which a book document is set on a platen in the apparatus of FIG. 2. FIGS. 3A and 3B are explanatory diagrams of a state in which an original is set on a platen in the apparatus of FIG. 2, where FIG. 3A illustrates a case where the document is positioned on the first reference surface, FIG. The block diagram of a positioning member. FIG. 3 is an explanatory diagram of a sensor structure that detects the size of a document set on a platen in the apparatus of FIG. 2.

Explanation of symbols

A Scanner unit B Document transport unit 1 Exterior casing 1h Hinge member 2 First platen (original travel platen)
2a Platen side end surface 3 Second platen (original fixing platen)
3a Platen upper surface 4 Feeder mechanism 5 Platen cover 6 Carriage 8 Photoelectric conversion element (image reading means)
9 Light source lamp 20 Lead roller 21 Guide member 22 Unloading roller 23 Paper feed stacker 24 Paper feed roller 28 Paper discharge roller 29 Paper discharge stacker 50 Positioning member 51 Reference surface 51a First reference surface 51b Second reference surface 52 Overhang portion 52S Detected Surface 54 Size discriminating means 55 Open / close sensor St Set reference detection sensor SS Size detection sensor SS1 First sensor SS2 Second sensor

Claims (6)

A platen on which the document is placed;
A positioning member disposed on a side edge of the platen for regulating at least one side of the document;
Optical reading means for reading a document placed on the platen;
With
The positioning member is
A first reference surface for restricting butting the edge of the document having a predetermined thickness or less;
An overhang covering the edge of the document from above;
A second reference surface that is disposed inside the overhang portion and that abuts and regulates the document edge of a predetermined thickness or more;
Have
An original having a predetermined thickness or less is inserted between the overhang portion and the upper surface of the platen and positioned on the first reference surface, and an original having a predetermined thickness or more is positioned on the second reference surface,
An image reading apparatus comprising: a set reference detection sensor for detecting the presence or absence of a document inserted between the overhang portion and the upper surface of the platen. The overhang portion is provided with a detected surface of the set reference detection sensor,
The image reading apparatus according to claim 1, wherein the detected surface is colored with a light absorption rate different from that of a document such as black. The image reading apparatus according to claim 1, further comprising:
A size detection sensor for detecting an edge of the document placed on the platen;
Size discriminating means for discriminating the document size by a signal from the size detection sensor;
Is provided,
The image reading apparatus characterized in that the size determining means determines the size of the document and / or the effective reading area of the image reading means based on detection signals from the size detection sensor and the set reference detection sensor. The size detection sensor includes a first sensor for detecting the other end edge of the document positioned on the first reference surface and a second sensor for detecting the other end edge of the document positioned on the second reference surface. And
The size determining means selects one of the first sensor and the second sensor based on a detection signal from the set reference detection sensor to determine the size of the document and / or the effective reading area of the image reading means. The image reading apparatus according to claim 3. The optical reading means includes
A line sensor that reads a document placed on the platen in line order;
It is composed of a carriage that carries this line sensor and moves in the sub-scanning direction,
5. The image reading apparatus according to claim 4, wherein the first sensor and the second sensor are arranged at a distance in a sub-scanning direction of the optical reading unit. The platen is provided with a platen cover that covers the placed document so as to be freely opened and closed.
This platen cover is equipped with an open / close sensor that detects the open / close state,
6. The image reading apparatus according to claim 5, wherein the carriage is controlled to be positioned at a reading start position set in advance by signals from the open / close sensor and the set reference detection sensor.

Images