JPH04135070U - Image reading device - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the density unevenness of image signals by reducing the unevenness of the amount of light irradiated onto the document. [Structure] The light source of the image reading device includes halogen lamps 21 and 22 in which a plurality of filaments 21b and 22b are arranged at predetermined intervals in long tubes 21a and 22a extending in the same direction as the reading line Q of the original P. Further, the halogen lamps 21 and 22 are arranged so that the filament 21b of the halogen lamp 21 faces between the filaments 22b of the other halogen lamp 22, and the halogen lamps 21 and 22 are arranged side by side.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is an image reading device that uses a long halogen lamp as a light source for illuminating documents. It's about location.

0002

[Conventional technology]

FIG. 2 is a schematic perspective view of a conventional image reading device. As shown in the figure , a conventional image reading device includes a light source 1 that irradiates light onto the document P, and a light source 1 that emits light from the document P. It is equipped with a lens 2 that forms an image of the light R and an image sensor 3 that detects this reflected light R. is being given. The light source 1 for irradiating light onto the document P may be a fluorescent lamp or the like. Halogen lamps, which have higher brightness than LEDs, are widely used.

0003 Furthermore, FIG. 3 is a block diagram showing the configuration of a signal processing circuit of a conventional image reading device. be. In this signal processing circuit, the image signal from the image sensor 3 is amplified by the amplifier 4. The peak value of this amplified image signal is set to A by the white peak hold circuit 5. /D converter 6, and the peak value of this image signal is used as a reference voltage. The image signal is binarized by the A/D converter 6, and this binarized image signal is It is output to the recognition unit 7.

0004

[Problem that the idea aims to solve]

However, the halogen lamp used in the above conventional device (the light source in Figure 2) 1), as shown in Figure 2, a plurality of filaments are placed inside a long cylindrical tube 1a. filament 1b are arranged at predetermined intervals, and when lighting, the filament 1b part The area between the filaments became a light-emitting part, and the area between the filaments became a non-light-emitting part. For this reason, the manuscript P The amount of light irradiated to the reading line Q is no longer uniform (it is bright in front of the light emitting part, It will be dark in front of the non-light emitting part. ), the problem of density unevenness occurring in the scanned image. There was a problem.

[0005] Here, FIG. 4 shows a line segment of the same density (PCS value 0) by the halogen lamp 1 of FIG. ．． 55) is a diagram showing the image sensor output when light is irradiated onto the image sensor. This diagram is Even though line segments 10 and 11 have the same density, the output of the image sensor A difference occurs in the waveform (waveform a of the read signal of line segment 10 in front of the light emitting part and non-emission The waveform b) of the read signal of the line segment 11 in front of the light section is shown.

[0006] Therefore, this invention was devised to solve the above problems, and The objective is to provide an image reading device with small unevenness in the amount of light irradiated onto the original. It is in.

[0007]

[Means to solve the problem]

The image reading device according to the present invention includes a plurality of photoelectric conversion elements arranged in a line. It is equipped with an image sensor that reads the original image line by line, and a reading line for the original. In the image reading device, the light source section has a light source section that irradiates light onto the top surface. A plurality of fillers are placed at predetermined intervals in a long tube that extends in the same direction as the reading line of the original. It has multiple halogen lamps with The filament position of one of the halogen lamps is different from that of the other halogen lamp. The above plurality of halogen lamps are placed facing each other between the filament positions. They are characterized by being arranged side by side.

[0008]

[Effect]

In the present invention, the filament position (i.e., the light emitting part) of the first halogen lamp is is directed to a position between the filament positions of other halogen lamps (i.e. non-light emitting part). When multiple (for example, two) halogen lamps are arranged side by side so that they overlap each other. Therefore, the amount of light irradiated on the reading line of the document is uniform.

[0009]

【Example】

FIG. 1 is a perspective view schematically showing the configuration of an embodiment of an image reading device according to the present invention. be.

0010 As shown in FIG. 1, the image reading device of this embodiment has two The halogen lamps 21 and 22 of the book and an imaging lens that forms an image of the reflected light R from the original P The main components are a lens 23 and an image sensor 24 that detects this reflected light R. Ru.

[0011] The halogen lamp 21 has a cylindrical shape extending in the same direction as the reading line Q of the original P. A long tube 21a and a plurality of tubes arranged at predetermined intervals within this tube 21a (in the figure, , five are shown. ) filament 21b. Halogena above The lamp 22 has the same structure as the halogen lamp 21, and has the same structure as the reading line Q of the document P. A long cylindrical tube 22a extending in the same direction, and arranged at predetermined intervals within this tube 22a. The filament 22b has a plurality of filaments 22b (five filaments are shown in the figure). There is.

0012 Here, FIG. 5 illustrates the positional relationship between the halogen lamp 21 and the halogen lamp 22. FIG. As shown in FIG. 5, the halogen lamp 21 and the halogen The gen lamps 22 are both arranged parallel to the reading line Q of the original P, and are arranged parallel to each other. They are arranged side by side so as to sandwich the reading line Q of the original P.

Further, as shown in FIG. 5, the halogen lamp 21 and the halogen lamp 22 are such that the filament 21b (or 22b) of one halogen lamp 21 (or 22) is located at the same position as the filament 21b (or 22b) of the other halogen lamp 22 (or 21). The filament 22b (or 21b) of the filament 22b (or 21b) is located opposite to the filament 22b (or 21b). This is because in a halogen lamp, the filament part becomes the light emitting part and the part between the filaments becomes the non-light emitting part, so the light emitting part of the halogen lamp 21 and the light emitting part of the halogen lamp 22 are arranged so that they do not overlap each other. This is to flatten the distribution of the amount of irradiation light on the reading line Q. As shown in FIG. 5, when the length of the filament 21b is L ₁ and the distance between adjacent filaments 21b is L ₂ , the halogen lamp 21 and the halogen lamp 22 are separated by (L ₁ +L ₂ )/ It is only necessary to dispose them with a displacement of 2 in the longitudinal direction.

[0014] The image sensor 24 also includes a plurality of photoelectric conversion elements arranged in a line. Reading of a document P that has children (for example, 2047) and moves in the direction A in FIG. The image on line Q is read line by line.

[0015] Note that the processing circuit for the signal output from the image sensor 24 is used to explain the conventional example. This is the same as that shown in FIG.

[0016] FIG. 6 shows a line segment 30 (P It is a figure which shows the image sensor output when light is irradiated to CS value 0.55). same As shown in the figure, in this example, when reading line segments 30 of the same density, The output waveform c of the image sensor 24 is almost the same for all line segments. .

[0017] As explained above, in this example, the filament of one halogen lamp is the filament position is opposite the position between the filament positions of the other halogen lamp. Since the two halogen lamps 21 and 22 are arranged side by side, The distribution of the irradiation light amount on the reading line Q of the document P can be flattened, and the unevenness of the irradiation light amount can be flattened. It is possible to reduce density unevenness in the image signal caused by one or more factors.

[0018] FIG. 7 is a plan view for explaining the structure and arrangement of a halogen lamp according to another embodiment. It is.

[0019] In this embodiment, two halogen lamps are used to illuminate the reading line Q of the document P. This embodiment is similar to the embodiment shown in FIG. 1 in that the unevenness of the amount of emitted light is reduced. However, Figure 1 In this example, the filament position of one halogen lamp is the halogen lamp itself to face the position between the filament positions of the However, in the embodiment shown in Fig. 7, the filler is installed at either end. By using two halogen lamps that are placed at different positions, The structure is such that there is no need to move the mounting position of the rogen lamp itself.

As shown in FIG. 7, the length of the filaments 31b and 32b is _L1 , the distance between adjacent filaments 31b (or 32b) is _L2 , and the length of the tubes 31a and 32a of the halogen lamp is L1. When the distances from the end to the end of the filament closest thereto are _L3 and _L4 , the halogen lamp 31 is set so that the relationship _L4 - _L3 = ( _L1 + _L2 )/2 is maintained. and 32 may be placed.

[0021] In addition, in the above example, the case where two halogen lamps were provided was explained, but in this case, The invention is not limited to this, but is equally applicable to devices equipped with three or more halogen lamps. Can be used.

[0022]

[Effect of the idea]

As explained above, according to the present invention, the filament position of the first halogen lamp is the filament positions of other halogen lamps, so that the Several halogen lamps are arranged side by side to illuminate the reading line of the document. The distribution of light intensity can be flattened, and the density of image signals caused by uneven irradiation light intensity can be reduced. It is possible to reduce the degree of unevenness.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing the configuration of an embodiment of an image reading device according to the present invention.

FIG. 2 is a schematic perspective view of a conventional image reading device.

FIG. 3 is a block diagram showing the configuration of a signal processing circuit of a conventional image reading device.

4 is a diagram showing image sensor output when line segments of the same density are irradiated with light by the halogen lamp of FIG. 2; FIG.

FIG. 5 is a plan view for explaining the positional relationship of halogen lamps.

FIG. 6 is a diagram showing image sensor output when line segments of the same density are irradiated with light by the halogen lamp of this embodiment.

FIG. 7 is a plan view for explaining the structure and arrangement of a halogen lamp according to another embodiment.

[Explanation of symbols]

21, 22, 31, 32 Halogen lamp 21a, 22a, 31a, 32a pipe 21b, 22b, 31b, 32b filament 23 Lens 24 Image sensor P Manuscript Q reading line R Reflected light

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Yasuhiko Shimizu Oki Electric, 1-7-12 Toranomon, Minato-ku, Tokyo Inside Kogyo Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. An image reading device comprising: an image sensor that includes a plurality of photoelectric conversion elements arranged in a line and reads an image of a document line by line; and a light source unit that irradiates light onto the reading lines of the document. In the apparatus, the light source section has a plurality of halogen lamps each having a plurality of filaments arranged at predetermined intervals in a long tube extending in the same direction as the reading line of the document, and one of the plurality of halogen lamps has a plurality of halogen lamps. An image reading device characterized in that the plurality of halogen lamps are arranged side by side so that the filament position of one halogen lamp faces the position between the filament positions of the other halogen lamps.