JPS6372262A - Picture reader - Google Patents

Abstract

PURPOSE:To attain the reading of wide range without mising or duplication of picture information by providing a totally reflection mirror on which a light from picture information of prescribed range split along in the main scanning direction is reflected while being directed into a prescribed photoelectric conversion element. CONSTITUTION:CCDs 32, 34, 36 are arranged at a proper interval on a line in parallel with the main scanning direction of an original A. A lens 38 is placed between the CCDs 32, 34, 36 and the original A and arranged to a position collecting the light from the picture information to each CCD. On the other hand, the total reflection mirrors 40, 42 are arranged between the lens 38 and the original A and reflecting faces 40a, 42a are set so as to be orthogonal in the main scanning direction. Through the constitution above, the picture information between b1 and-b2 of the original A in the main scanning direction is read by the CCD 32 and the information between the b2 and-b3 is read by the CCD 34 and the information between the b3 and-b4 is read by the CCD 36 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading device, and more particularly, to an image reading device that includes an optical system including a plurality of photoelectric conversion elements arranged in a line along the main scanning direction of a scanned object and a total reflection mirror. The present invention relates to an image reading device that can read image information carried on the object to be scanned without missing or duplicating the image information by combination.

In recent years, in the fields of printing and prepress, streamlining of work processes,
2. Description of the Related Art Image scanning, recording and reproducing systems that electrically process image information carried on a document to create a film original are widely used for the purpose of improving image quality.

This image scanning, recording and reproducing system basically consists of an image reading device and an image reproducing device. That is, in the image reading device, a document that is conveyed in a sub-scanning direction in an image reading section is main-scanned by a photoelectric conversion element, and the image information is converted into an electrical signal. Next, the image information photoelectrically converted by the image reading device is subjected to arithmetic processing such as gradation correction and edge enhancement according to the plate-making conditions in an image reproducing device, and then the image information is processed by light such as laser light. The signal is converted into a signal and recorded and reproduced on a record carrier made of a photosensitive material such as film.

Note that this recording carrier is developed by a predetermined developing device and used as a film original for printing or the like.

By the way, when the image reading device main scans a document and reads its image information, a CCD is used as a photoelectric conversion element.
(charge coupled device) is mainly used. Here, the CCD is a device in which a large number of electrodes for photoelectric conversion are arranged in a line shape at high density, and the number of pixels of an easily available COD is about several thousand at most. Therefore, one C
When image information of a document is read using a CD, its resolution becomes quite coarse. On the other hand, producing a dedicated COD with a larger number of electrodes arranged in order to improve resolution requires a large manufacturing cost and is not realistic.

Therefore, in order to obtain high resolution, a plurality of CCDs are generally used to read image information. For example, in FIG. 1, a document A carrying image information has image information between one end a and a central portion a2 transmitted through a lens 2 to a CCD 4.
Further, image information between the center portion a2 and the other end portion a3 is read by the CCD 8 via the lens 6. By combining the electric signals from each CCD 4 and 8, image information between a, , and 23 can be obtained with high resolution.

However, if the condition shown by the broken line A occurs due to uneven conveyance of the document A due to the conveyance system, curvature of the document A, or misalignment of the lens 2.6, the section ΔL near the center a2 will be affected by the CCD 4. and 8, and therefore, image information in this section ΔL may be missing. On the other hand, when the document A is in the state indicated by the broken line A2, the image information of the section ΔM near the center a2 of the document A is read by both the CCDs 4 and 8 in duplicate.

As a result, when configured as shown in Figure 1, two CCDs
A portion of the image information read by steps 4 and 8 is missing or overlapped, and when the image information is reproduced by the image reproducing device, the image becomes unclear.

In order to solve this problem, there is a system in which CCDs 4 and 8 are arranged as shown in Figure 2 (Japanese Patent Laid-Open No. 58-111568). In this case, CCDs 4 and 8 are arranged close to each other. The chief ray 10b of the CCD 4 reads the image information near the center a2 of the document A.
The angle θ2 between the principal ray 12b of the CCD 8 and the principal ray 12b of the CCD 8 is set smaller than the angle θ between the principal rays 11Qa and 12a in FIG. Therefore, for example, when the document A is in the state indicated by the broken line A, the section ΔL' in which image information is missing near the center portion a2 is smaller than the missing section ΔL in FIG. Similarly, when the document A is in the state indicated by the broken line A2, the overlap area ΔM' of image information near the center a2 is also smaller than the overlap area ΔM in FIG.

As a result, even if the document A varies between the broken lines A+ and Az, there is very little loss or duplication of image information read by the CCDs 4 and 8.

However, in an image reading device configured in this way,
As in the case described above, a plurality of lenses 2 and 6 are required depending on the number of CCDs 4 and 8 used, which not only makes it extremely troublesome to adjust the positions of each lens 2 and 6, but also requires high precision. It has been pointed out that manufacturing the lenses 2 and 6 requires a great deal of time and cost.

On the other hand, there is another conventional technique constructed as shown in FIG. 3 (Japanese Patent Laid-Open No. 58-202661).

In this case, the light from the image information carried on the document A is reflected by the total reflection mirror 14 set at an angle of 45@ with respect to the scanning surface of the document A, and then passes through the lens 16 to the half mirror 18. The beam enters and is split into two directions. That is, the half mirror 18 is arranged parallel to the total reflection mirror 14, and the original A is placed above one end of the half mirror 18.
A C0D 20 for reading image information between one end a1 and a central portion a2 is disposed, and a C0D 20 for reading image information between the central portion a2 and the other end a3 of the document A is disposed behind the other end of the half mirror 18. A CCD 22 for reading image information is provided.

In the image reading device configured in this way, for example, when the document A moves in the direction of the arrow Z, the CCDs 20 and 22
Although the positions of one end a and the other end a of the original A vary, the position of the center a2 remains unchanged. Therefore, C
When the image information between a, , and az read by the 0D20 is combined with the image information between ats and 33 read by the CCD 22, it is possible to obtain an image signal without omission or overlap. In addition, only one lens 16 is required for condensing the light from the image information (this makes it easier to adjust its position and reduces costs).

However, since the image information carried on the document A is input to the CCDs 20 and 22 via the half mirror 18, the amount of light is attenuated to less than 50%, making it impossible to obtain a clear image. has been done.

The present invention has been made to overcome the above-mentioned disadvantages, and includes arranging a plurality of photoelectric conversion elements in a line along the main scanning direction of the object to be scanned, and connecting the photoelectric conversion elements and the object to be scanned. A total reflection mirror having a reflective surface perpendicular to the main scanning direction is disposed between the scanning direction, and the image information carried on the object to be scanned is transmitted to the plurality of surfaces through the total reflection mirror and a common optical system. It is an object of the present invention to provide an image reading device that can read the image information over a wide range without missing or duplicating it by reading it with a photoelectric conversion element, and has a simple configuration.

In order to achieve the above object, the present invention provides an image reading device that uses a photoelectric conversion element to main scan and read image information carried on a scanned object that is conveyed in the sub-scanning direction. a plurality of photoelectric conversion elements arranged in a line, an optical system that focuses light from the image information on each of the photoelectric conversion elements, and a reflective surface perpendicular to the main scanning direction; It is characterized by comprising a total reflection mirror that directs and reflects light from a predetermined range of image information divided along the main scanning direction toward a predetermined photoelectric conversion element.

Next, preferred embodiments of the image reading device according to the present invention will be described in detail with reference to the accompanying drawings.

4 and 5, reference numeral 30 indicates the main body of the image reading device according to the present invention. This main body part 30 includes CCDs 32, 34 and 36 as photoelectric conversion elements for photoelectrically reading image information carried on the document A, and optical devices for condensing light from the image information onto each CCD 32, 34 and 36. It basically consists of a lens 38, which is a system, and two total reflection mirrors 40 and 42.

The CCDs 32, 34 and 36 are arranged at appropriate intervals on a straight line parallel to the main scanning direction of the document A (arrow Y direction). A lens 38 is located between the CCDs 32, 34 and 36 and the original A, and directs light from image information to the CCDs 32, 34 and 36.
and 36, respectively. On the other hand, total reflection mirrors 40 and 42 are disposed between the lens 38 and the document A. In this case, the total reflection mirror 42
The reflective surface 40a of the total reflection mirror 42 and the reflective surface 42a of the total reflection mirror 42 are set to face each other and to be orthogonal to the main scanning direction (arrow Y direction).

Here, image information A between bl and b2 in the main scanning direction of the document A is read by the CCD 32, and b2)b,
The image information between is read by CCD34, and
Image information between b3 and b4 is read by the CCD 36. Note that it is preferable to dispose the light sources that illuminate the document A closely along the main scanning direction, since this improves the accuracy of reading image information.

The image reading device according to the present invention is basically configured as described above, and its operation and effects will be explained next.

Therefore, the light from the image information of bl in the original A is incident on the reflective surface 40a of the total reflection mirror 40 along the principal ray 44a, and then is reflected and incident on one end of the CCD 32 via the lens 38. Further, the light from the bt image information is incident on the reflective surface 40a of the total reflection mirror 40 along the principal ray 44b, and then is reflected and incident on the other end of the CCD 32 via the lens 38. Therefore, the image information between b, , and b is read by the CCD 32. Further, the light from the image information b2 in the document A is not reflected by the total reflection mirror 40, and is transmitted to the lens 3 along the principal ray 46a.
8 and enters one end of the CCD 34. Similarly, b,
The light from the image information passes through the lens 38 along the chief ray 46b.
The light is incident on the other end of the CCD 34 via. As a result, b2
) b, the image information between is read by the CCD 34. Furthermore, the light from the image information of the image in the document A travels along the principal ray 48a to the reflection surface 42 of the total reflection mirror 42.
After entering a, it is reflected and passes through the lens 38 to the CCD 3.
The light is incident on one end of 6. Further, the light from the image information b4 is directed toward the reflection surface 42 of the total reflection mirror 42 along the principal ray 48b.
After entering a, it is reflected and passes through the lens 38 to the CCD 3.
The light is incident on the other end of 6.

Therefore, the image information between b and b4 is read by the CCD 36.

In this way, the image information between A to B4 of the original A is read by the CCDs 32, 34 and 36 and converted into electrical signals. In this case, CCD32.34 and 3
The image information read by 6 is electrically processed into a predetermined array, and an image signal for one line along the main scanning direction (direction of arrow Y) is formed. Note that the entire surface of the original A is two-dimensionally scanned by being transported in the sub-scanning direction (direction of arrow X) by a transporting means (not shown).

Here, in the original flIA, , b2 question and s,
, b, is reflected by total reflection mirrors 40 and 42, and then enters CCDs 32 and 36 via lens 38. In this case, the principal ray 44b incident on the CCD 32 from b2 is reflected by the reflection surface 44 of the total reflection mirror 40.
It is reflected by a.

Therefore, the chief ray 46a entering the CCD 34 from b2
The angle φ at which the principal ray 44b and the principal ray 44b intersect is extremely small. Similarly, the principal light 1548a incident on the CCD 36 and the CC
The intersection angle φ with the principal ray 46b incident on D34 is also extremely small. Therefore, this angle φ is equal to the principal ray 10 shown in FIG.
The angle θ1 between a and 12a and the chief ray IQ shown in FIG.
It is much smaller than the angle θ2 between b and 12b.

As a result, for example, as shown in FIG. 5, even if the document A is in the state indicated by the broken line A1, the distance Δ between the principal rays 45a, 46b and 48a, 48b with respect to the document A is
l is extremely small, so that the loss of image information carried on the document A is suppressed to a minimum. Similarly, when the document A is in the state indicated by the broken line A2, the distance Δm between the principal rays 46a and 46b and between 48a and 48b is extremely small, and therefore, the duplication of image information is also suppressed to a minimum. Also, one lens 38 for three CCDs 32, 34 and 36.
Since they are commonly used, it is possible to not only easily adjust the position of the lens 38, but also to reduce costs.

In addition, in the embodiment described above, the CCD which is a photoelectric conversion element
Although the example in which the CCDs 32, 34 and 36 are arranged in a straight line is shown, the CCDs 32, 34 and 36 are arranged in an arc shape, and the total reflection mirrors 40 and 42 are provided with predetermined positions corresponding to each CCD 32, 34 and 36. It is also possible to arrange the angle between the condenser lens 38 and the document A. Furthermore, if the distance of the document A in the main scanning direction is short, only the CCDs 32 and 34 may be used.

In this case, the total reflection mirror 42 becomes unnecessary.

As described above, according to the present invention, a plurality of photoelectric conversion elements are arranged in a line along the main scanning direction of an object to be scanned, and image information carried on the object to be scanned is transmitted in the main scanning direction. The light from the image information is reflected as necessary by a total reflection mirror having orthogonal reflecting surfaces, and the light from the image information is imaged on a desired photoelectric conversion element via a common optical system.

Therefore, the angle at which the principal rays from the image information of the scanned object that are directed toward adjacent photoelectric conversion elements intersect is small, and therefore, omission or duplication of image information between the photoelectric conversion elements is suppressed. As a result, high resolution can be maintained and accurate images can be reproduced. Furthermore, since the optical system can be used in common for each photoelectric conversion element, the structure is simple and inexpensive, and there is also an advantage that operations such as position adjustment of the optical system are extremely easy.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory front view of an image reading device according to the prior art, FIG. 2 is an explanatory front view of an image reading device according to another prior art, and FIG. 3 is a configuration of an image reading device according to still another prior art. FIG. 4 is a perspective view of the configuration of an image reading device according to the present invention, and FIG. 5 is a front explanatory view of the image reading device according to the present invention. 30... Main body part 32.34.36...
CCD38...Lens 40.42...
Total reflection mirror A...Original F [G, 1

Claims (2)

[Claims] (1) In an image reading device that main-scans and reads image information carried on a scanned object that is conveyed in the sub-scanning direction, a plurality of photoelectric conversion elements are arranged in a line along the main scanning direction of the scanned object. a conversion element, an optical system that focuses light from the image information on each of the photoelectric conversion elements, and a reflecting surface perpendicular to the main scanning direction, and is divided along the main scanning direction. 1. An image reading device comprising a total reflection mirror that directs and reflects light from a predetermined range of image information toward a predetermined photoelectric conversion element. (2) In the apparatus according to claim 1, three photoelectric conversion elements are arranged in a line, and a pair of opposing photoelectric conversion elements perpendicular to the main scanning direction are arranged between the optical system and the object to be scanned. A total reflection mirror is provided, and among the first to third ranges of image information divided along the main scanning direction of the scanned object, the first
Image information in a range is reflected by a first total reflection mirror and read by a first photoelectric conversion element via the optical system, and image information in a second range is converted into a second photoelectric conversion element only via the optical system. An image reading device configured to read image information with an element, reflect image information in a third range with a second total reflection mirror, and read the image information with a third photoelectric conversion element via the optical system.