JP2004054121A - Picture reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a picture reader in which deviation in a position is prevented of an original due wind pressure or the like caused when an original pushing cover is closed. <P>SOLUTION: The picture reader reading the picture of the original mounted on an original placing table 22 comprises: a first movement restraint member 30 movable in the main scanning direction (x direction) on the original placing table 22; and a second movement restraint member 32 movable in the sub scanning direction (y direction) on the original placing table 22. The first movement restraint member 30 and the second movement restraint member 32 are moved to a position where the members come in contact with the outer periphery of the original mounted on the original placing table 22 by using a corner section as a reference, so that the movement of the original in the main scanning direction and the sub scanning direction is restrained. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading device that reads an image of a document placed on a document table.
[0002]
[Prior art]
2. Description of the Related Art As an image reading apparatus, there is a flat bed scanner (FBS) that opens a document holding cover such as a platen cover, places a document on a document placing table such as a placing glass, and reads an image of the placed document. In the case of a thick original such as a book, reading may be performed with the platen cover open, but usually, reading is performed with the platen cover closed. Further, the image reading apparatus is provided with a size detecting means for detecting a standard size such as A4 or B5. For example, when the document is A4 size, the image of the reading area corresponding to the A4 size on the mounting glass is read. Is read.
[0003]
Many copiers or facsimile machines can selectively use an ADF (automatic document feeder) and an FBS. General sheet documents such as A4 paper or B5 paper are often read using the ADF. On the other hand, a thick original such as a book cannot be used with the ADF, and is often read by the FBS. However, even a sheet document may be read by the FBS because a plurality of sheets are stapled.
[0004]
[Problems to be solved by the invention]
In particular, when the FBS is used for a sheet document, when the platen cover is closed, wind pressure is applied to the document on the mounting glass, and the position of the document often shifts. For this reason, inconveniences such as the scanned original being printed at an angle often occur.
[0005]
In addition, when using the FBS, an original of an irregular size is often read, as well as a thick original. However, the size detecting means described above is generally set to detect a fixed size, and often cannot detect a non-fixed size. If the document size cannot be accurately detected, an unnecessary area where the document placed on the document table does not exist is read.
[0006]
The present invention has been made in view of such circumstances, and includes a first and a second movement suppressing members that are movable in a main scanning direction and a sub-scanning direction, respectively. It is an object of the present invention to provide an image reading apparatus capable of preventing a document from being displaced due to the like.
[0007]
In addition, the present invention provides an image reading apparatus that can accurately detect a document size by including first and second position detection units that detect the movement positions of the first and second movement suppression members, respectively. That is another purpose.
[0008]
In addition, the present invention includes a selection unit that selects a smaller one of the original size detected by the conventional size detection unit and the size detected by the first and second position detection units, thereby providing the first and second sizes. Another object of the present invention is to provide an image reading apparatus capable of preventing erroneous size detection when the second movement suppressing member is not retracted outside the readable area.
[0009]
[Means for Solving the Problems]
An image reading apparatus according to a first aspect of the present invention is an image reading apparatus for reading an image of a document placed on a document placing table, wherein the first movement restricting member is movable on the document placing table in a main scanning direction; A second movement suppressing member movable on the table in the sub-scanning direction, wherein the first and second movement suppressing members suppress movement of the document on the document table.
[0010]
In the first invention, the first movement suppressing member is moved along the main scanning direction to be aligned with the position on the document table in contact with the outer periphery of the document, and the stationary document is moved in the main scanning direction (position Deviation). Similarly, the second movement suppressing member is moved along the sub-scanning direction, and is adjusted to a position in contact with the outer peripheral portion of the document on the document table, so that the stationary document is moved in the sub-scanning direction (displacement). Suppress. When a document is positioned on the document table on the basis of a corner, the outer peripheral portion facing the outer peripheral portion of the document contacted by the first and second movement suppressing members is in contact with the outer frame of the document table, and movement of the entire document is prevented. Be suppressed. Therefore, the original does not move even when wind pressure or the like is applied.
[0011]
An image reading apparatus according to a second aspect of the present invention is the image reading apparatus according to the first aspect, wherein first position detecting means for detecting a movement position of the first movement suppressing member over an entire reading area on the original placing table, and all reading on the original placing table. A second position detecting means for detecting a moving position of the second movement suppressing member over the region, wherein an image in a reading region corresponding to the detected moving position is read.
[0012]
In the second invention, the first position detecting means detects the movement position of the first movement suppressing member over the entire reading area on the document table, and the second position detecting means detects the entire reading area on the document table. The movement position of the second movement suppression member over the range is detected. Although the moving position can be detected at a predetermined interval, it is preferable to detect the moving position continuously at a minute interval. It is possible to accurately detect the size of an irregular document on the document table, specify a reading area (document existing area) from the detected movement position, and read an image in the specified reading area.
[0013]
An image reading apparatus according to a third aspect of the present invention is an image reading apparatus which detects a size of a document placed on a document placing table by size detection means and reads an image in a reading area corresponding to the detected size. A first movement suppressing member movable in the main scanning direction on the table, first position detecting means for detecting a moving position of the first movement suppressing member over the entire reading area on the document table, A second movement suppressing member movable in the sub-scanning direction, a second position detecting means for detecting a moving position of the second movement suppressing member over the entire reading area on the document table, and a document moving based on the detected moving position. Selecting means for selecting a smaller one of the size and the size detected by the size detecting means, wherein the first and second movement suppressing members suppress the movement of the original on the original placing table, and read according to the selected size. To read the image in the area Characterized that you have.
[0014]
In the third invention, the size of the document is detected by the size detecting means. For example, a document size is detected by using a sensor provided in advance to detect a fixed size document edge such as A4 or B5. Further, the first and second movement suppressing members similar to the first invention suppress the movement of the document on the document placing table, and the first and second position detecting means similar to the second invention respectively use the first and second position detecting means. The movement position of the movement suppression member is detected. The selector selects the smaller one of the size of the document corresponding to the moving position detected by the first and second position detectors and the size detected by the size detector. The reading area is specified from the selected size, and the image in the specified reading area is read.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings showing the embodiments.
In this description, a facsimile apparatus having the function of a copier and capable of performing document copying and facsimile transmission / reception will be described as an example.
[0016]
(First Embodiment)
FIG. 1 shows an example of a facsimile apparatus provided with an image reading apparatus according to the present invention. The facsimile apparatus includes a control unit (CPU: Central Processing Unit) 1, a reading unit 2 for reading a document, a modem (fax modem) 9 capable of facsimile communication, and an analog line L such as a public telephone line network. (Network Control Unit) 10 for controlling the facsimile apparatus, a recording unit 3 for recording a facsimile received image or a document image read by the reading unit 2 on a sheet, and an operation unit 5 including various keys used for operating the facsimile apparatus. A display unit 4 for displaying an operation state of the facsimile apparatus or characters input from the operation unit 5, a ROM (Read Only Memory) 6 for storing various programs and data necessary for the operation of the facsimile apparatus, Stores temporary data generated during program execution A RAM (Random Access Memory) 7, an image memory 8 for storing a document image or a facsimile reception image read by the reading unit 2, and a CODEC 11 for encoding or decoding image data are provided.
[0017]
The above-described hardware units (1 to 11) are connected to the bus 12 and controlled by the CPU 1. The CPU 1 reads a computer program stored in the ROM 6 and executes various functions.
[0018]
An example of the reading unit 2 is shown in FIGS. In the examples of FIGS. 2 and 3, the reading unit 2 includes a rectangular parallelepiped housing 26, a platen cover (document pressing cover) 20 attached to one side of the upper surface of the housing 26 so as to be openable and closable, and A rectangular mounting glass (document mounting table) 22 provided, and can freely move along the main scanning direction (x direction) on the mounting glass 22. And a first movement suppressing member 30 for suppressing the movement of the document in the main scanning direction when the document is moved to a position in contact with the scanning glass 22 along the sub-scanning direction (y-direction) orthogonal to the main scanning direction. A second movement suppressing member that can move freely and that suppresses the movement of the document in the sub-scanning direction when moved to a position in contact with the document outer peripheral portion on the placing glass;
[0019]
The original 40 is placed on the placing glass 22 with reference to the corner portion provided with the triangular mark 24a shown in FIG. The first movement suppressing member 30 and the second movement suppressing member 32 individually move along two sides of the outer frame 24 sandwiching the corner provided with the mark 24a. Hereinafter, the first movement suppression member 30 and the second movement suppression member 32 may be collectively referred to as movement suppression members 30 and 32.
[0020]
The reading unit 2 is capable of reading ADF (automatic document feeder) and FBS (flat bed scanner). When reading a document by the ADF method, the platen cover 20 is closed, a bundle of documents is set on a document set section (not shown) on the platen cover 20, and reading is performed while separating and taking in documents one by one. When reading a document by the FBS method, the platen cover 20 is opened, the document is placed on the placing glass 22, the platen cover 20 is closed, and reading is performed with the document stationary on the placing glass 22. However, in the case of a thick original such as a book, reading is performed with the platen cover 20 open or in a state where it is not completely closed.
[0021]
Although not shown, a light source for irradiating a document placed on the placing glass 22 with light and a light path of light reflected from the document are changed as members constituting the reading unit 2 in the housing 26. , A moving mechanism for moving the light source and the mirror, and a large number of photoelectric conversion elements arranged in the main scanning direction, and an image sensor such as a CCD (charge coupled device) line sensor to which light from the mirror is incident through a condenser lens. And With such a configuration, while moving a carriage (not shown) on which a light source and the like are mounted in the sub-scanning direction, a CCD line sensor having a longitudinal direction in the main scanning direction (a CCD line sensor arranged parallel to the main scanning direction) To read the original image line by line. The image read by the CCD is stored in the image memory 8 by the CPU 1.
[0022]
As shown in FIG. 3, a width sensor for detecting the width of the original (length in the main scanning direction) on the placing glass 22 using a sensor such as a photodiode, a phototransistor, or a CCD, as shown in FIG. 42, and a length sensor 44 for detecting the length of the document (the length in the sub-scanning direction). In the example of FIG. 3, a CCD line sensor for reading constituting the reading unit 2 is used as the width sensor 42, and a plurality of photoelectric sensors arranged along the y direction are used as the length sensor 44. I have. The length sensor 44 is arranged so as to be able to detect the presence or absence of a standard document end such as A4 or B5. The width sensor 42 is also arranged so as to be able to detect the presence or absence of a document edge in a predetermined size range such as B5 to A3.
[0023]
A detector 28 for detecting that an angle θ formed between the platen cover 20 and the outer frame 24 is equal to or less than a predetermined angle is provided near the platen cover 20 mounting portion of the outer frame 24 on the upper surface of the housing 26. The detector 28 uses a push-in type automatic return switch or the like. If the detector 28 is pressed down while the platen cover 20 is being closed, a detection signal is sent from the detector 28 to the CPU 1, and the CPU 1 To emit light.
[0024]
When the detector 28 is pressed down while the platen cover 20 is closed, the light source emits light, the width sensor 42 and the length sensor 44 detect the document width and the document length, and a detection signal is sent to the CPU 1. However, the document size that can be detected by the width sensor 42 and the length sensor 44 is limited to a fixed size or a size close to a fixed size. The CPU 1 obtains the document width and the document length based on the detection signal, and stores them in the RAM 7.
[0025]
FIG. 4A shows an example of the movement suppressing members 30 and 32. The movement suppressing members 30 and 32 have a shape in which a long flat plate is bent into an L-shape, and are formed in L-shaped grooves formed in the outer frame 24 so as to extend along the main scanning direction or the sub-scanning direction. Are slidably fitted. The height H1 of the movement suppressing members 30 and 32 based on the mounting glass 22 is lower than the height H0 of the outer frame 24 based on the mounting glass 22 so that the platen cover 20 closes. The surfaces of the movement suppressing members 30 and 32 that are in contact with the mounting glass 22 are, for example, black so that they can be distinguished from the original (white) when the original is read using the CCD. Therefore, it is possible to prevent the movement suppressing members 30 and 32 from being erroneously recognized as a document.
[0026]
The movement position of the movement suppressing members 30 and 32 is detected based on, for example, a change in the resistance value according to the movement of the movement suppressing members 30 and 32, and the rotation position of the pulley according to the movement of the movement suppressing members 30 and 32, and the like. It is possible to detect based on. For example, as shown in FIG. 4B, by moving the movable terminal C of the variable resistor having the terminals AB at both ends in conjunction with the movement of the movement suppressing members 30 and 32, the terminal A-C Alternatively, it is possible to detect the movement position of the movement suppressing members 30 and 32 based on a change in the resistance value between the terminals BC. The detection signal of the resistance value is sent to the CPU 1, and based on a conversion table stored in, for example, the ROM 6, a document width or a document length corresponding to the resistance value is acquired and stored in the RAM 7. In this case, the variable resistor and the CPU 1 operate as means for detecting the positions of the movement suppressing members 30 and 32, and detect the document size continuously over the entire readable area.
[0027]
Alternatively, as shown in FIG. 4C, a pair of pulleys 52 on the left and right sides, a belt 50 mounted between the pulleys 52 and rotating the pulleys 52 with the movement of the movement suppressing members 30 and 32, and a pulley 52 By providing a rotary encoder (not shown) for detecting the rotation angle of the pulley 52, the movement of the movement suppressing members 30, 32 causes the pulley 52 to rotate, and the movement position can be detected from the rotation angle of the pulley 52. is there. The rotation angle detection signal is sent to the CPU 1, and based on a conversion table stored in, for example, the ROM 6, obtains a document width or document length corresponding to the rotation angle and stores it in the RAM 7. In this case, the pulley 52, the belt 50, the rotary encoder, and the CPU 1 operate as means for detecting the positions of the movement suppressing members 30, 32, and continuously detect the document size over the entire readable area.
[0028]
In addition, as shown in FIG. 5, the readable area 22 a on the mounting glass 22 is almost always smaller than the outer frame 24. When reading the original of the maximum size, if the movement suppressing members 30 and 32 are moved out of the readable area 22a, the movement suppressing members 30 and 32 do not affect the reading of the original. When the readable area 22a has the same size as the outer frame 24, for example, as shown in FIG. 6, a retreat area for the movement suppressing members 30, 32 is formed in the outer frame 24.
[0029]
The CPU 1 operates as a means for selecting a smaller one of the document size based on the width sensor 42 and the length sensor 44 and the document size based on the movement position of the movement suppressing members 30 and 32. However, when the movement suppressing members 30 and 32 are retracted, the CPU 1 sets the reading area using the document size based on the width sensor 42 and the length sensor 44.
[0030]
When the length L1 of the first movement suppressing member 30 is shorter than the distance L0 from the outer frame 24 to the width detection position by the width sensor 42 as shown in FIG. The size detection of the width sensor 42 is not affected. Similarly, when the length D1 of the second movement suppressing member 32 is shorter than the distance D0 from the outer frame 24 to the length detection position by the length sensor 44, the moving position of the second movement suppressing member 32 becomes longer. The size detection of the sensor 44 is not affected. In this case, the surfaces of the movement suppressing members 30 and 32 that are in contact with the mounting glass 22 can be white. In this example, as described above, since the reading CCD line sensor is also used as the width sensor 42, the width detection position is the light source when performing width detection using the reading CCD line sensor. Is the irradiation position. Accordingly, making the length L1 shorter than the distance L0 means that the position of the carriage is controlled so that the light source irradiates a position farther than the length L1 from the outer frame 24 when performing width detection.
[0031]
The length L1 of the first movement suppressing member 30 and the length D1 of the second movement suppressing member 32 are set to the vertical and horizontal directions of the postcard in order to prevent mutual interference when moving the postcard-sized document. Is preferably shorter than the length of each.
[0032]
Next, reading of a document using the image reading apparatus according to the present invention will be described. The operator opens the platen cover 20 and places the document 40 on the placing glass 22 based on the mark 24a. After placing the document 40, the movement suppressing members 30 and 32 are moved to a position in contact with the outer periphery of the document 40. If the document 40 is not thick, the platen cover 20 is closed. At this time, since the movement of the document 40 on the placing glass 22 is suppressed by the movement suppressing members 30 and 32, no displacement occurs.
[0033]
While the platen cover 20 is being closed, the detector 28 is pressed down, and the CPU 1 emits a light source, specifies the document size based on the detection signals output from the width sensor 42 and the length sensor 44, and stores the document size in the RAM 7. I do. The CPU 1 detects the movement position of the movement suppression members 30 and 32 and stores the detected position in the RAM 7. The CPU 1 selects the smaller one of the document size based on the width sensor 42 and the length sensor 44 and the document size based on the movement suppressing members 30 and 32.
[0034]
FIG. 8 shows an example of a procedure for selecting a document size. The CPU 1 determines whether the first movement suppressing member 30 has been retracted out of the readable area (S10). When the document is retracted (S10: YES), the CPU 1 selects a document width based on the width sensor 42 (S14). If not retracted (S10: NO), the CPU 1 compares the document width based on the width sensor 42 with the document width based on the first movement suppressing member 30 (S12). If the document width based on the width sensor 42 is smaller (S12: YES), the CPU 1 selects the document width based on the width sensor 42 (S14), and the document width based on the first movement suppressing member 30 is smaller. In this case (S12: NO), a document width based on the first movement suppressing member 30 is selected (S16). The selection of the document length (S18, S20, S22, S24) is performed in the same manner as the selection of the document width (S10, S12, S14, S16).
[0035]
The CPU 1 controls the reading unit 2 to read an image in the reading area corresponding to the selected document size, and controls, for example, the recording unit 3 to record the read image on a sheet.
[0036]
In the above-described embodiment, either one of the document size based on the width sensor 42 and the length sensor 44 and the document size based on the movement suppressing members 30 and 32 is selected. When no selection is made, the reading area can be set based on the document size based on the movement suppressing members 30 and 32. In the embodiment, an example in which a CCD line sensor for reading is used as the width sensor 42 has been described. However, a CCD line sensor for width detection or another photoelectric sensor is provided separately from the CCD line sensor for reading. Can also be arranged.
[0037]
The first and second position detecting means for detecting the positions of the movement suppressing members 30 and 32 include the variable resistor and the CPU 1 shown in FIG. 4B, or the pulley 52 and the belt 50 shown in FIG. However, the present invention is not limited to a rotary encoder (not shown) and the CPU 1, and any position detecting means can be used.
[0038]
【The invention's effect】
According to the first aspect, by suppressing the movement of the original by the first and second movement suppressing members, it is possible to prevent the original from being displaced due to wind pressure or the like generated when the original pressing cover is closed.
[0039]
According to the second aspect, the first and second position detecting means detect the movement positions of the first and second movement suppressing members, respectively, to accurately detect the document size, and to detect the reading area according to the document size. Images can be read. Thus, for example, when a thick original such as a book is read with the original holding cover opened or not completely closed, only the original portion is read, and the edge is printed in black. Can be prevented.
[0040]
According to the third aspect, the smaller one of the document size detected by the conventionally used size detecting means and the size detected by the first and second position detecting means is selected by the selecting means, It is possible to prevent erroneous size detection when the first and second movement suppressing members are not retracted outside the readable area. For example, when reading a B5 size document with the first and second movement suppressing members positioned at the A4 size position, the B5 size detected by the size detection unit is selected.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an example of an image reading apparatus according to the present invention.
FIG. 2 is a perspective view showing a part of a reading unit.
FIG. 3 is a plan view showing a part of a reading unit.
4A is a diagram illustrating an example of a movement suppressing member, and FIGS. 4B and 4C are diagrams illustrating an example of position detection of the movement suppressing member.
FIG. 5 is a plan view showing a part of a reading unit.
FIG. 6 is a plan view showing a part of a reading unit.
FIG. 7 is a plan view showing a part of a reading unit.
FIG. 8 is a flowchart illustrating an example of a procedure for selecting a document size.
[Explanation of symbols]
1 CPU (selection means)
2 Reading unit 30 First movement suppressing member 32 Second movement suppressing member 42 Width sensor (size detecting means)
44 Length sensor (size detection means)

Claims (3)

In an image reading apparatus for reading an image of a document placed on a document table, a first movement suppressing member movable in the main scanning direction on the document table, and a first movement suppressing member movable in the sub-scanning direction on the document table. An image reading apparatus, comprising: a second movement suppressing member, wherein the first and second movement suppressing members suppress movement of a document on the document placing table. First position detecting means for detecting a moving position of the first movement suppressing member over the entire reading area on the document table; and a second detecting means for detecting a moving position of the second movement suppressing member over the entire reading area on the document table. 2. The image reading apparatus according to claim 1, further comprising: two position detecting means for reading an image in a reading area corresponding to the detected moving position. In an image reading apparatus, the size of a document placed on a document table is detected by a size detecting unit, and an image in a reading area corresponding to the detected size is read.
A first movement suppressing member that is movable in the main scanning direction on the document table,
First position detection means for detecting the movement position of the first movement suppression member over the entire reading area on the document table;
A second movement suppressing member movable on the document table in the sub-scanning direction;
Second position detecting means for detecting a moving position of the second movement suppressing member over the entire reading area on the document table;
Selecting means for selecting a smaller one of the size of the document based on the detected moving position and the size detected by the size detecting means, wherein the first and second movement suppressing members suppress the movement of the document on the document table. An image reading apparatus configured to read an image in a reading area corresponding to a selected size.

Images