JPH05153344A - Scanner - Google Patents

Abstract

PURPOSE:To read a book or a sheet original with high resolution by placing a placing face of the sheet or the book original respectively to a focal point of the image sensor and a position biased toward the image sensor by a half of the focal depth from the focal point. CONSTITUTION:When a book original B is read, the original is placed on an original placing face 5 of an original platen. The placing face 5 is located at a position (b) biased toward an image sensor 2 by a half of a focal depth S with respect to a focal position (a) of a rod lens of the image sensor 2. The sensor 2 is moved between Y and Z along the original placing face 5 with an image sensor moving device to read an original. When the sheet original is read, the original is sequentially carried by the original carrier mechanism on the sheet original placing face 6 located at the focal position (a) of the rod lens to read the original by the sensor 2 placed at a point X under the placing face 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner device using a contact image sensor.

[0002]

2. Description of the Related Art Some scanner devices include a transparent document table having a document placing surface on which a document is placed and a sensor for reading the content of the document from the side opposite to the document placing surface of the document table. .. In this type of scanner device, a document moving type in which the image sensor is stationary and the document moves on the document mounting surface, and a document is stationary on the document table and the image sensor moves along the document mounting surface. There is an image sensor moving type. The former format is particularly suitable for reading sheet-like originals and is widely adopted in facsimile machines and the like, and the latter format is suitable for reading book-like originals in addition to sheet-like originals. Suitable for

A document moving type scanner device can easily add a document feeding device and can set a large number of documents on the document feeding device and sequentially move them on the document table. As described above, since the original document feeder can improve the operability of the scanner device, it is also installed in the sensor moving type scanner device. If the sensor moving type scanner is equipped with a document feeder, the original is read by the normal sensor moving type when the document is a book, and the document is moved by the document feeding device as a document moving type when the document is a sheet. , Read the contents of the original with the image sensor stationary.

The image sensor provided in the scanner device has conventionally had a reduction optical system, but recently, a contact type image sensor is often used because of its small size, high resolution, and easy handling. It is like this. This image sensor uses a rod Leon's array, and although this lens has high resolution, it has the drawback of having a small depth of focus.

The depth of focus of the rod lens array is determined by the aperture angle of the rod lens array, and is currently 4
The range in which a black and white pattern of lp / mm can be read at a resolution of 40% or more is about 1 mm (1 mm at the front 0.5 mm and the rear 0.5 mm with the focus as the center).

[0006]

As described above, since the contact type image sensor has a small depth of focus, in the sensor moving type scanner device, the installation position of the image sensor,
It becomes important which position on the platen in the thickness direction the focus position matches. In the case of handling only sheet-shaped originals, if the original placing surface of the original table is aligned with the focus position, it is possible to read in almost the best state. However, in the case of a book-shaped original, the seam between the pages of the original may be outside the range of the depth of focus of the image sensor away from the original placing surface of the original table, and the resolution may be insufficient.

Therefore, by arranging the document mounting surface of the document table on the side of the image sensor by a distance half the depth of focus of the image sensor, the image sensor divides the pages of the book-like document into pages. The seam falls within the depth of focus of the image sensor, and the seam can be read with high resolution.

However, if the position of the document placing surface of the document table is set so that the book-like document can be read at a high resolution, the position of the document placing surface can read the sheet-like document at a high resolution. It will be in a difficult position. However, in general, 70-80% is a sheet-like document and the remaining 30-20% is a book-like document. Therefore, if the position of the document placement surface of the document table is set in consideration of the book-like document as described above, the performance of the image sensor is 100% for a sheet-like document that occupies a large proportion of the document. It will be read in a state where it cannot be exhibited.

Despite such problems,
The position of the document placement surface of the document table in the conventional sensor moving type scanner device is set by the image sensor side by about half the depth of focus of the image sensor. That is, when viewed from the image sensor side, the book-shaped original and the sheet-shaped original are set at halfway positions and used.

As described above, in the conventional sensor-moving type scanner device using the image sensor, the position of the document mounting surface, that is, the installation position of the image sensor is inappropriate for the book-like document and the sheet-like document. The sensor performance was not fully exerted.

The present invention has been made in view of the above circumstances. For a book-like document, the depth of focus of the contact image sensor can be maximized to allow high-resolution reading, and a sheet-like document can be read. It is an object of the present invention to provide a scanner device capable of reading an original with a maximum resolution at the focal position of the contact image sensor.

[0012]

In order to achieve the above object, a scanner device according to the first invention of the present application is a document table on which a sheet-like document and a book-like document are placed, and a document placement surface of the document table. An image sensor for reading each of the originals placed on the opposite side of the original plate, an image sensor moving mechanism for moving the image sensor along the original plate, and the sheet-like original for the original plate. And a document transport mechanism for moving the document table along with the document table, wherein the document table is located at a position closer to the image sensor by half the depth of focus than the focus position of the image sensor. An original placing surface and a second original placing surface for placing a sheet-like original placed at the same position as the focal position of the image sensor, and the image sensor moving mechanism moves the image sensor forward. The image sensor is moved along the first document placing surface of the document table at a position facing the first document placing surface, and the image sensor is moved at a position facing the second document placing surface of the document table. It is characterized by being stationary.

The scanner device according to the second aspect of the invention is a document table on which a sheet-like document and a book-like document are placed, and a document table provided on the opposite side of the document placing surface of the document table. An image sensor for reading each of the originals, an image sensor moving mechanism for moving the image sensor along the original plate, an original conveying mechanism for moving the sheet original along the original plate, and the image sensor An image sensor displacement mechanism for displacing the image sensor along the optical axis direction of the image sensor with respect to the original table,
The document table has a document placement surface on which a sheet-like document is placed and a document placement surface on which a book-like document is placed, at the same position,
The image sensor displacement mechanism is a first position for a book-like document which has a distance obtained by subtracting half the depth of focus from the focal length of the image sensor with respect to the document placement surface of the document table. And a second position for a sheet-shaped document, which has the same distance as the focal length of the image sensor with respect to the document table, and the image sensor moving mechanism includes the image sensor. Is to move the image sensor along the document surface of the document table when the image sensor is in the first position, and to make the image sensor stand still when the image sensor is in the second position. It is what

[0014]

In the scanner device of the first invention, when reading a book-like document, the document is placed on the first document placement surface of the document table and the image sensor is moved by the image sensor moving mechanism to the first document plate of the document table. The document is read by moving it along the document placement surface of. This makes it possible to effectively use the depth of focus of the image sensor to read the page-to-page seam of a book-like document with high resolution. When reading a sheet-shaped original, the image sensor moving mechanism causes the image sensor to stand still at a position facing the first original placing surface of the original table, and the original conveying mechanism places the original on the second original placing table. The original is conveyed on the surface, and the image sensor reads the original moving on the second original placement surface. As a result, the image sensor can read the sheet-like document at the optimum focus position with high resolution.

In the scanner device of the second invention, when reading a book-like document, the document is placed on the document placing surface of the document table, and the image sensor displacement mechanism positions the image sensor at the first position. The image sensor moving mechanism moves the image sensor along the document placement surface of the document table. Further, when reading a sheet original, the original conveying mechanism sequentially conveys the original on the original placing surface of the original table, and the image sensor displacement mechanism positions the image sensor at the second position and moves the image sensor. The mechanism causes the image sensor to stand still at a position facing the document placement surface of the document table.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention will be described with reference to FIGS. The scanner device in this embodiment is provided in the fax machine. In FIGS. 1 and 2, 1 is a document table, 2 is an image sensor, 3 is an image sensor moving mechanism, and 4 is a document conveying mechanism.

The document table 1 is a rectangular plate made of a transparent material such as glass and has a size larger than that of a sheet-shaped document or a book-shaped document. The document table 1 is horizontally supported by a member (not shown). Most of the upper surface of the document table 1 is the first document placement surface 5, and one end in the length direction is formed as the second document placement surface 6 at a position higher than the first document placement surface 5. ing.

The image sensor 2 is formed by arranging a large number of rod lens arrays arranged in the vertical direction in series and accommodated in the case, and has the same length as the width of the document table 1. In FIG. 3, a is the focal point of the rod lens array, b is the focal depth limit point on the front side (rod lens array side) around this focal point a, and c is the focal depth limit point on the rear side (anti-rod lens array side). Is. The depth of focus S is between the depth of focus limit point b and the depth of focus limit point c, and the focus a
Between the focal depth limit point b and the focal depth limit point c, and between the focal point a and the focal depth limit point c are half the focal depth S. The image sensor 2 is arranged on the platen 1 along the width direction.
That is, the image sensor 2 moves along the length direction of the document table 1 to read the document placed on the document table 1.

Here, the first document placing surface 5 of the document table 1 is for placing a book-like document, and is half the distance to the focal position a of the rod lens in the image sensor 2 at the focal depth S. It is at the position of the focal depth limit point b according to the image sensor 3 side. The second document placing surface 6 is for placing a sheet-like document and is at the same position as the focal position a of the rod lens in the image sensor 2. That is, the difference between the first document placing surface 5 and the second document placing surface 6 corresponds to a distance half the depth of focus S.

The image sensor moving mechanism 3 includes a guide 7 for movably supporting the image sensor 2 along the lengthwise direction of the document table 1, and a belt 8 supported by a pair of pulleys 9 and connected to the image sensor 2. Is equipped with. One of the pair of pulleys 9 is rotated by an electric motor (not shown). Then, in the image sensor moving mechanism 3, when the pulley 9 is rotated by the electric motor, the belt 8 supported by the pulley 9 is rotated, the image sensor 2 is pulled by the belt 8 and guided by the guide 7, and the document table 1 is moved. Is moved along the length of the.

The document feeding mechanism 4 is arranged outside one end of the document table 1 and is set on the document setting table 10 on which a plurality of sheet-shaped recording papers P are stacked and set. Feeding rollers 11 for feeding the originals P one by one from the uppermost layer toward the second original placing surface 5 of the original table 1, and provided above the second original placing surface 6 of the original table 1. The platen roller 12, the paper feed cover 13, the document guide 14, the upper cover 15 disposed above the document placing surface 5 of the document table 1 and rotatable in the vertical direction, and provided inside the upper cover 15. Belt 1 supported by a pair of pulleys 17
6. A document receiver 18 arranged outside the other end of the document table 1 is provided. Feeding roller 11, platen roller 1
2. The pulley 17 is rotated by an electric motor (not shown).

Then, in the document feeding mechanism 4, when the feeding roller 11 is rotated, the sheet-like documents P set on the document setting table 10 are transferred one by one from the topmost one to the second sheet of the document table 1. Of the document P, and the unrolled document P is conveyed by the rotating platen roller 12 on the second document placement surface 6 of the document table 1. When the pulley 17 is rotated, the belt 16 is rotated in the direction of the arrow shown.
The original that has passed the second original placing surface 6 passes through the first original placing surface 5 of the original table 1 by the rotation of the belt 16 and is conveyed to the original receiver 18. The electric motor that drives the feeding roller 11, the platen roller 12, and the pulley 17 is controlled by a control circuit (not shown).

A detector 19 is provided in the opening formed in the document setting table 10. The detector 19 detects the presence or absence of the sheet-shaped document P on the document setting table 10. For example, the detector 19 irradiates a light beam and detects the presence of the document based on the presence or absence of the reflection. The detection information of the detector 19 is output to the control circuit.
A case where a sheet-shaped document is read by the scanner device configured as described above will be described.

When reading a sheet-like original, a plurality of sheet-like originals P are stacked and placed on the original set table 10 as shown in FIGS. When the detector 19 detects the presence of the sheet-shaped document P and sends the detection information to the control circuit, the detection circuit receives it and sets the scanner device to the sheet-shaped document reading mode.

The image sensor 2 is moved by the operation of the image sensor moving mechanism 3 described above to the second document placing surface 6 of the document table 1, that is, the X point below the platen roller 12, and is stationary. Further, the operator confirms that the upper cover 15 is on the original table 1 side, and turns on the start switch. By the operation of the document transport mechanism 4 described above, the documents placed on the document setting table 10 are sequentially read one by one.
The sheet is fed to the second document placing surface 6 and is conveyed to the document receiver 18 via the first document placing surface 5. Here, the image sensor 2 reads the content of the document P when the sheet-shaped document P moves on the second document placement surface 6. The second document placing surface 6 is at the focal position a in the rod lens array of the image sensor 2. Therefore, the image sensor 2 uses the sheet-shaped document P.
Is read at the highest resolution at the focal position a in the rod lens array. A case of reading a book-like document will be described.

When reading a book-like document, as shown in FIG. 3, the portion of the book-like document B to be read is opened and placed on the first document placement surface 5 of the document table 1. In this case, the seam between the pages of the book-shaped document B is the first document placement surface 5
It is located near the focal position a of the rod lens array. That is, the entire portion of the page to be read of the book-shaped document B is located within the focal depth S of the rod lens array.

When the detector 19 detects that there is no document on the document setting table 10 and sends the detection information to the control circuit, the detection circuit receives the detection information and sets the scanner device to the book-like document reading mode.

The image sensor moving mechanism 3 moves the image sensor 2 to a position below the first document placing surface 5 of the document table 1 and makes it stand by. The operator turns on the start switch after confirming that the upper cover 15 is on the document table 1 side. The image sensor moving mechanism 3 moves the image sensor 2 along the length direction of the document table 1 between the points Y and Z at the lower part of the first document placement surface 5 of the document table 1. During this movement, the image sensor 2 reads the content of the book-shaped original document B placed on the first original document placement surface 5. This makes it possible to effectively use the depth of focus of the rod lens array of the image sensor 3 to read the book document B with high resolution. An embodiment of the second invention will be described with reference to FIG.

The scanner device in this embodiment is provided in the facsimile machine. The scanner apparatus of this embodiment is the same as the scanner apparatus of the first embodiment of the first invention described above, except that an image sensor displacement mechanism for changing the configuration of the document table and displacing the image sensor moving mechanism with respect to the document table is provided. ing.

In FIG. 4, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. That is, 2 is an image sensor, 3 is an image sensor moving mechanism, and 4 is a document conveying mechanism. Further, in FIG. 4, 1A is a document table, and 20 is an image sensor displacement mechanism. The document table 1A has a uniform thickness throughout and has a flat upper surface serving as a document placement surface 1a. That is, in the document table 1A, the document placing surface on which the sheet-like document is placed and the document placing surface on which the book-like document is placed are at the same position. The image sensor displacement mechanism 20 includes a carrier 21 that supports the entire image sensor moving mechanism 3.
And an elevating device for supporting and elevating the carrier 21, for example, a hydraulic cylinder 22. The carrier 21 is moved up and down by the hydraulic cylinder 22, that is, displaced relative to the document table 1 along the optical axis direction of the rod lens array of the image sensor 2. As a result, the image sensor 2 becomes
Is displaced along the optical axis direction of the rod lens array. Specifically, the image sensor 2 has a T point at a first position which is a distance obtained by subtracting a half of the focal depth S from the focal length of the rod lens array with respect to the original placing surface 1a of the original table 1. A case where a sheet-shaped document is read by the scanner device configured as described above, which is selectively located at the second position U point which has the same distance as the focal length of the rod lens array with respect to the document table 1, will be described.

The image sensor moving mechanism 3 moves the image sensor 2 to a point X below the platen roller 12 and stands still. Further, the carrier 21 is moved up and down by the operation of the hydraulic cylinder 22 of the image sensor displacement mechanism 20, and the image sensor 2 is positioned at the U point of the second position. Then, the sheet conveying mechanism 4 conveys the sheet-shaped originals P one by one on the original placing surface 1a of the original table 1. The image sensor 2 reads the sheet-like document P passing through the point X. Therefore, the image sensor 2 can read the sheet-shaped document P with the highest resolution at the focal position a in the rod lens array. A case of reading a book-like document will be described.

The book-like original B is placed on the original placing surface 1a of the original table.
Put it on top. The image sensor 2 is located at the first position S by the operation of the hydraulic cylinder 22 of the image sensor displacement mechanism 20. Then, the image sensor moving mechanism 3 operates so that the image sensor 2 is moved to the original placing surface 1a
Then, move between the Y point and the Z point along the length direction. The image sensor 2 reads the book-shaped document B during this movement. Therefore, the image sensor 2 can read the book-shaped document B with high resolution within the focal depth S of the rod lens array. The first invention and the second invention are not limited to the above-mentioned embodiments and can be modified in various ways.

[0033]

As described above, in the scanner device of the first invention, the first original for placing a book-like original placed at the position on the image sensor side by half the depth of focus from the focus position of the image sensor. It is provided with a document table having a placement surface and a second document placement surface for placing a sheet-like document at the same position as the focal position of the image sensor.

In the scanner device of the second invention, the first position for the book-like document is such that the image sensor has a distance with respect to the document placement surface of the document table, which is obtained by subtracting half the depth of focus from the focal length of the image sensor. The image sensor displacement mechanism is provided to selectively position the position and a second position for a sheet-shaped document, which has the same distance as the focal length of the image sensor with respect to the document table.

Therefore, according to the first invention and the second invention, it is possible to maximize the depth of focus of the contact type image sensor for reading a book-like document and read it at a high resolution. It is possible to obtain a scanner device capable of reading a document sheet with the maximum resolution at the focal position of the contact image sensor.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the first invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a diagram illustrating a configuration of a document table.

FIG. 4 is a sectional view showing an embodiment of the second invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Original document table, 2 ... Image sensor, 3 ... Image sensor moving mechanism, 4 ... Original document conveyance mechanism, 20 ... Image sensor displacement mechanism.

Claims (2)

[Claims] 1. A document table on which a sheet-like document and a book-like document are placed, and an image sensor which is provided on the opposite side of the document placing surface of the document table and which reads the respective documents placed on the document table. And an image sensor moving mechanism for moving the image sensor along the platen, and a document feeding mechanism for moving the sheet-like document along the platen, the platen for the image sensor. A first document placing surface for placing a book-like document placed at a position closer to the image sensor side by half the depth of focus than the focus position;
The image sensor moving mechanism has a second document placing surface for placing a sheet-like document at the same position as the focal position of the image sensor, and the image sensor moving mechanism places the image sensor on the first document placing on the document table. The image sensor is moved along the first original placing surface at a position facing the placing surface, and the image sensor is stopped at a portion facing the second original placing surface of the original table. Scanner device. 2. A document table on which a sheet-like document and a book-like document are placed, and an image sensor which is provided on the opposite side of the document placing surface of the document table and reads the respective documents placed on the document table. An image sensor moving mechanism for moving the image sensor along the document table; a document feeding mechanism for moving the sheet document along the document table;
An image sensor displacing mechanism for displacing the image sensor with respect to the document table along an optical axis direction of the image sensor, wherein the document table has a document placement surface on which a sheet-like document is placed and a book-like configuration. The original placement surface on which the original is placed is at the same position, and the image sensor displacement mechanism causes the image sensor to move from the focal length of the image sensor to half the depth of focus with respect to the original placement surface of the original table. The first position for book-like manuscript with the distance subtracted,
The image sensor moving mechanism is configured to selectively position the second position for a sheet-shaped document having the same distance as the focal length of the image sensor with respect to the document table side. The image sensor is moved along the document surface of the document table when the image sensor is in the first position, and the image sensor is stopped when the image sensor is in the second position. Scanner device.