JPH0324856A - Image reader - Google Patents

Abstract

PURPOSE:To obtain picture information with a high precision by reading picture information on a scanned body while displacing photoelectric transducers, which are arranged at intervals of a prescribed length in the main scanning direction and are arranged in plural columns in the subscanning direction, in the subscanning direction. CONSTITUTION:Though a document A is shifted in the direction of an arrow Z orthogonal to the scan face at the time of reading the image, picture information on a main scanning line B is accurately read. That is, CCDs 44a to 44d are displaced in the subscanning direction of an arrow X by an eccentric cam 45, and the same effect that CCDs are arranged on one straight line is practically obtained. Thus, picture information on the main scanning line B is read in the state free from line deviation. Since a lens 46 as a common optical system is used to read picture information on the main scanning line B, the position of picture information read by CCDs 44a to 44d is not deviated, and the occurrence of drop-out of picture information or double read is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a method for displacing photoelectric conversion elements arranged in a plurality of rows along the main scanning direction of an object to be scanned in the sub-scanning direction so as to carry them on the object to be scanned. The present invention relates to an image reading device that reads image information.

[Prior Art] In recent years, when an image reading device main-scans a document and reads its image information, a CCD (charge-coupled device) has come to be used as a photoelectric conversion element. Here, the C
A CD has a large number of pixels (electrodes) that perform photoelectric conversion arranged in a line shape at high density, and the number of pixels of a CCD that can be easily handled manually is about several thousand at most. Therefore, when image information of a document is read by a single CCD, its resolution will be quite coarse. On the other hand, a dedicated CC with a larger number of electrodes arranged to increase resolution
Producing D 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. As this type of conventional technology, the technology described below has already been proposed.

[Prior art 1] As shown in FIG.
is read by the CCD 4 via the central part a2
The image information between the
Read by D8. And each CCD4 and 8
By combining the electrical signals from , image information between a, , and a3 is obtained with high resolution.

[Prior art 2] As shown in FIG. 6, light from image information carried on document A is reflected by a total reflection mirror 14 set at an angle of 45 degrees with respect to the scanning surface of document A. Thereafter, the light enters the nof mirror 18 via the lens 16 and is split into two directions. That is, the half mirror 18 is arranged parallel to the total reflection mirror 14, and above one end thereof is a CCD 20 for reading image information between one end a1 and the center a2 of the original A. Further, at the rear of the other end side of the half mirror 18, a central portion a2 of the original A is provided.
and the other end a3 C C D2
2 is provided (see Japanese Patent Laid-Open No. 58-202661).

[Prior art 3] As shown in FIGS. 7a and 7b, light from image information carried on a document A is set at angles of φ1 and φ2 (φ1 > φ2) with respect to the scanning surface of the document A. After being reflected by the two total reflection mirrors 24a and 24b, it is reflected by the CCDs 28a and 30a and the CCD 28 via the lens 26.
b, 30b. That is, CCD28a, 30
As shown in FIG. 7b, the CCDs 28b and 30b are arranged in two rows and alternately along the main scanning direction of the document A (direction perpendicular to the paper surface in FIG. The image information of the document A reflected by the reflection mirror 24a is read by the CCDs 28a and 30a, and the image information of the document A reflected by the total reflection mirror 24b is read by the CCD.
28b, 30b (Special Publication Publication No. 57-4)
See No. 6266>.

[Problems to be Solved by the Invention] However, the following problems have been pointed out with respect to the prior art as described above.

■ Regarding Prior Art 1, the original A was curved due to the curvature of the platen glass on which the original A was placed or the bending of the guide etc. when the conveyance device was installed, resulting in the state shown by the broken line AI as shown in Fig. 5. case,
The section ΔL near the center a2 is not read by the CCDs 4 and 8, and therefore the image information of this section ΔL may be missing. On the other hand, if the document A moves in the direction of the arrow Z and reaches the state indicated by the broken line A2, the document A
The image information of the section ΔM near the central part a2 of the CCD
4 and 8 will be read redundantly.

As a result, a portion of the image information read by the two CCDs 4 and 8 is missing or duplicated, resulting in an inconvenience that when the image information is reproduced by the image reproducing device, the image becomes inaccurate.

■ Regarding Prior Art 2, when the document A moves in the direction of arrow Z, the positions of one end a and the other end a3 of the document A on the CCDs 20 and 22 change, but the position of the center a2 remains unchanged. .

However, the image information carried on the document A is transmitted to the CCDs 20 and 22 via the half mirror l8, and a
The optical path is divided into image information between l and a2 and image information between a2 and a3, and the image information is read. Therefore, C C D20,2
The amount of light reaching 2 is halved. Therefore, by doubling the light intensity or halving the light intensity, C C D2
It is necessary to perform electrical processing in a state where the dynamic range of 0 and 22 is narrowed.

■ Regarding Prior Art 3, in this case, the light from the image information passes through the total reflection mirrors 24a, 2
Since the light is guided to the CCDs 28a, 28b, 30a, and 30b via the light beams 4b, the amount of light does not decrease by half as described above. Further, electrical processing at the connecting portions of each CCD 28a, 28b, 30a, and 30b is also easy.

However, when the document A moves in the direction of the arrow Z, when the electric signals related to the image information obtained from the CCDs 28a, 28b, 30a, and 30b are combined to obtain image information, as shown in FIG. There is a possibility that line deviation may occur in the scanning direction.

The present invention has been made to solve the above-mentioned problems, and it suppresses the occurrence of deviations in the main scanning direction and sub-scanning direction of image information due to displacement of the document surface with respect to the photoelectric conversion element, and An object of the present invention is to provide an image reading device that can easily process electrical signals including the following.

[Means for Solving the Problems] In order to solve the above-mentioned problems, 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 a sub-scan direction. photoelectric conversion elements separated by a predetermined interval in the scanning direction and arranged in a plurality of rows in the sub-scanning direction; an optical system that focuses light from the image information on each of the photoelectric conversion elements; and the photoelectric conversion elements. and a displacement means for displacing in the sub-scanning direction,
By displacing the photoelectric conversion element in the sub-scanning direction by the displacement means, light from image information on a continuous scanning line is directed to each photoelectric conversion element to read the image information.

[Function] According to the present invention, when image information carried on a document is read through an optical system using photoelectric conversion elements arranged in a plurality of rows along the main scanning direction, the photoelectric conversion elements are aligned in the sub-scanning direction. By displacing the image information on the scanning line of the original, it is possible to read the image information on the scanning line of the original without any deviation, despite the fluctuation of the original surface.

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

In FIG. 1, reference numeral 40 indicates the main body of the image reading device according to the present invention. This main body part 40 is disposed in a housing 42, and CCDs 44a, 44b, 44C, and 44d photoelectrically read image information carried on the document A
, an eccentric cam 45 which is a displacement means for displacing the housing 42, and an eccentric cam 45 which is a displacement means for displacing the housing 42, and a
44a to 44d, and a lens 46 which is an optical system for condensing light onto 44a to 44d.

The housing 42 is constructed to be elongated along the main scanning direction Y of the original A, and guide members 48a148b extending along the sub-scanning direction
, 52b. In this case, both ends of the guide members 48a and 48b are attached to the base 51 (
(see Figure 2). An eccentric cam 45 comes into contact with the center of one side surface of the housing 42 . This eccentric cam 45
The rotating shaft 56 that supports the rotary shaft is connected to a power source (not shown), and by driving the power source, the eccentric cam 45 rotates.
The housing 42 reciprocates along the sub-scanning direction X in the direction of the arrow. Moreover, in the guide members 48a and 48b,
Compression springs 50a and 50b are wound between the other side surface of the housing 42 and the base 51 to press the housing 42 toward the eccentric cam 45.

As shown in FIG. 2, CCDs 44 a to 44 d housed in the housing 42 are arranged on two straight lines perpendicular to the optical axis of the lens 46 and parallel to the main scanning direction Y of the document A. Arranged at intervals. That is, on the first straight line there are no CCDs.
44a, 44c are arranged, and these CCDs 44a, 4
4c, among the image information on the main scanning line B of the document A, b
Image information between 4 and b, and between b2 and b3 is read.

Further, on the second straight line, C
CD44b, 44d are arranged, and these CCD44b
, 44d read the image information between b3 and b, and between b1 and b2.

The image reading device according to this embodiment is basically constructed as described above, and its operation and effects will be explained next.

First, Fig. 1 and Fig. 2 vi! In state J, the housing 42 is pressed against the eccentric cam 45 by the elastic force of the compression springs 50a and 50b, and in this state, the lens 46
The optical axis intersects with the first straight line along which the CCDs 44a and 44c are arranged (see FIG. 3a). In this case, light from the image information b4 in the original A enters one end of the CCD 44a via the lens 46 along the principal ray 58d. Light from the image information of bs enters the other end of the CCD 44a via the lens 46 along the principal ray 58e. Therefore, the image information between b< and bs is C C D44
H (see Figure 1).Also, b3
The light from the image information passes through the lens 46 along the chief ray 58C.
It enters one end of C C D44 c through C C D44 c. on the other hand,
Light from the image information b2 enters the other end of CCD44C via the lens 46 along the chief ray 58b.

Therefore, the image information between b2 and b3 is C C D44 c
(Figures 1, 2 and 3a)
reference).

Next, the eccentric cam 45 is rotated via the rotating shaft 56 by driving the power source. In this case, the housing 42 moves in the direction opposite to the sub-scanning direction X against the elastic force of the compression springs 50a and 50b. Therefore, the second straight line along which the CCDs 44b and 44d are arranged intersects the optical axis of the lens 46 (see FIG. 3b). In this case, the light from the image information of b3, b, in original A is the principal ray 5
C C D44 through lens 46 along 8C158d
Since it is incident on b, the image information between b3 and b4 is transmitted to the CCD.
44b. Similarly, light from the image information of b+ and bz in original A is principal ray 58a, 58
Since the light enters the CCD 44d along the direction b through the lens 46, the image information between b and b2 is read by the CCD 44d (see FIG. 3b).

In this way, the image information between b1 and b5 on the main scanning line B of the original A is read by the CCDs 44a to 44d and converted into electrical signals. In this case, C
The image information read by the CDs 44a to 44d is electrically connected to form an image signal for one scanning line along the main scanning direction Y. Note that since the document A is conveyed in the sub-scanning direction (direction of arrow X) by a conveyance means (not shown), image information of the entire surface thereof is converted into an electrical signal.

Here, for example, in the embodiment according to the present invention, even if the document A moves in the direction of the arrow Z perpendicular to the scanning surface during image reading, it is possible to accurately read image information on the main scanning line B. I can do it. That is, since the CCDs 44a to 44d are displaced in the direction of the arrow along the sub-scanning direction X by the eccentric cam 45, the same effect as when they are arranged substantially in a straight line can be obtained. As a result, image information on the main scanning line B can be read without line deviation. Also, since the image information on the main scanning line B is read using the lens 46, which is a common optical system, C C D4 as in the case of the prior art shown in FIG.
4a to 44d, the position of the image information does not shift, and therefore, situations such as missing image information or duplicate reading do not occur. Moreover, in this case, since no half mirror is used, the dynamic range of the CCDs 44a to 44d does not become narrower.
Image reading at high resolution can be maintained, and signal processing of the read images becomes extremely easy.

Next, FIG. 4 shows another embodiment of the image reading device according to the present invention. In this embodiment, a piezoelectric element 66 is used as a displacement means for reciprocating the housing 42 in which the CCDs 44a to 44d are disposed. It should be noted that other elements constituting the image reading device are the same as those in the above-described embodiment, and therefore are given the same reference numerals and detailed explanation thereof will be omitted.

In FIG. 4, reference numeral 60 indicates the main body of the image reading apparatus according to this embodiment. C C D44 a to 44d
The housing 42 in which the lever 62 is disposed is attached to one end of a lever 62 that is pivotally supported by a fulcrum 64. On the other hand, the lever 62
A piezoelectric element 66 is attached between the other end and the base 51 of the image reading device. In this case, a power source (not shown) is connected to the piezoelectric element 66. By applying a voltage to the piezoelectric element 66 from this power source, the piezoelectric element 6
6 is displaced, thereby reciprocating the other end of the lever 62 in the direction of the arrow along the sub-scanning direction X. As a result, the housing 42 reciprocates in the direction of the arrow along the sub-scanning direction X via the fulcrum 64. Then, as in the case described above, the CCDs 44a to 44d are displaced to coincide with the optical axis of the lens 46, and the image reading action for the original A is achieved.

[Effects of the Invention] As described above, according to the present invention, while displacing in the sub-scanning direction photoelectric conversion elements arranged at predetermined intervals in the main scanning direction and arranged in multiple rows in the sub-scanning direction, It is on guard to read the image information of the object to be scanned. In this case, even if the scanned object moves toward the photoelectric conversion element, the read image will not shift in the main scanning direction and the sub-scanning direction, and therefore image information can be obtained with high precision. I can do it. Furthermore, since no processing is required to correct such deviations, the posture becomes extremely simple and easy.

[Brief explanation of drawings]

1 is a perspective view showing the structure of an embodiment of an image reading device according to the present invention; FIG. 2 is a plan view illustrating an arrangement of photoelectric conversion elements constituting the image reading device shown in FIG. 1; Figure 3 a and b are the first
FIG. 4 is an explanatory diagram showing another embodiment of the image reading device according to the present invention, and FIG. 5 is an explanatory diagram of the operation of the image reading device shown in FIG. FIG. 6 is a perspective view showing the structure of an image reading device according to another prior art, and FIG. FIG. 7b is an explanatory plan view of the arrangement of photoelectric conversion elements constituting the image reading device shown in FIG. 7a. 40... Main body part 42... Housing 44a
~44d...CCD 45...Eccentric cam 60
...Body part 62...Lever 66...
・Piezoelectric element A...500 originals FIG1 X Shizuichi FIG. 2 FIG. 5

Claims (1)

[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, photoelectric conversion elements are arranged at predetermined intervals in the main-scanning direction and arranged in multiple rows in the sub-scanning direction. a photoelectric conversion element; an optical system that focuses light from the image information on each of the photoelectric conversion elements; and a displacement means that displaces the photoelectric conversion element in the sub-scanning direction; An image reading device characterized in that light from image information on a main scanning line is directed to each photoelectric conversion element to read the image information by displacing the photoelectric conversion element in a sub-scanning direction.