JPH05344289A - Image reader - Google Patents

Abstract

PURPOSE:To provide an image reader which corresponds to the reading of a transmission original and a reflecting original, which can easily control a scan driving system and in which reading density and reading areas can conveniently be set by adjusting them to an original which is usually used. CONSTITUTION:The image reader obtaining image information by scanning the surface of the reflecting or transmission original by using light emitted from light sources 1a and 1b, converging reflected or transmitted light by image- forming lenses 3a and 3b, making it incident on photoelectric conversion elements 4a and 4b, detecting an electric signal corresponding to the reflection rate or the transmission rate of the surface of the original as an image signal is provided with a first travel body 6 scanning the surface of the fixed reflecting original, and a second travel body 8 which scans the original at scan speed half the first travel body 6 and is provided with the original read stand 7 of the transmission original 2b. Maximum effective read length in the auxiliary scan direction Y of the transmission original 2b is set to be half maximum effective read length in the auxiliary scan direction Y of the reflecting original 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to read a reflective original document and a transparent original document such as a film with high accuracy with a single device, and the respective reading densities and reading areas can be used for ordinary original documents. The present invention relates to an image reading apparatus that can be conveniently set.

[0002]

2. Description of the Related Art Conventionally, many proposals have been made for an image reading apparatus capable of selecting a mode for reading a reflective original and a mode for reading a transparent original such as film. One reflective and transmissive original that can select between a mode in which a film image is projected and imaged on the surface of the original reading table by a film projector and the projected image is read, and a mode in which the original placed on the original surface is read. An example of an image reading device that can be read by the above is disclosed in Japanese Patent Laid-Open No. 2-174462 under the title of "Image reading device". In this case, a mode in which a reading optical system scans a document placed on a document reading table is read, and a film image is projected and imaged on the document surface by a film projector, and the projected image is read by the reading optical system. In a device provided with a selection mode capable of selecting the reading mode, the reading optical system is stopped in the scanning direction in the film reading mode, and the reading scanning is performed by moving the film. As a result, in the film reading mode, since the scanning is performed by fixing the reading optical system and moving the film, the projection lens and the mirror are included as compared with the conventional device that projects and reads the entire surface of the film at once. The optical system can be made compact, and moreover, only the slit-shaped area needs to be illuminated, and the illumination system can also be made compact.

[0003] Further, both a reflection and transmission method of a system in which a mode in which a transparent original such as a film is read by illuminating it from the side opposite to the imaging lens and the image sensor and a mode in which an original placed on the original surface is read can be selected. Image reading devices capable of reading a single document are disclosed, for example, in Japanese Patent Application Laid-Open No. 3-58566 under the title "Image Reading Device".

In the "image reading device" of JP-A-3-58566, when a reflective original document and a transparent original document such as a film are read by one image reading device, separate light sources and original document readings are used for the reflective reading and the transparent reading. A mode in which a table is provided and the original set on the original reading table is scanned by the scanning optical system to read the original, and a transparent original such as film is cut across the optical path between the imaging lens of the optical reading system and the original surface. It has a mode of moving and reading. Here, when reading a transparent original, one of the reflection mirrors of the above-mentioned reading optical system is made movable. This makes it possible to select a mode for reading a reflective original and a mode for reading a transparent original, and since the distance from the transparent original to the imaging lens is shortened, the transparent original is read at a high magnification, that is, with high accuracy. It becomes possible to read.

[0005]

As an image reading device,
Japanese Patent Laid-Open No. 3-58566 discloses an example of an apparatus that can read both a transparent original and a reflective original. As shown in the prior art, the size of a commonly used transparent original is smaller than that of the reflective original. Also, the required reading density is often higher for transparent originals.

In the inventions disclosed in Japanese Patent Laid-Open No. 3-58566, when a transparent original such as a film is read, the position of the imaging lens commonly used for reading the reflective original and the transparent original is changed to perform the enlarged reading. It is carried out. For this reason,
In order to obtain an accurate enlargement ratio, it is necessary to accurately determine the position (including the 6-dimensional posture) of the imaging lens before and after the movement. In general, it is difficult to move the imaging lens and set the position within the lens aberration range, and in order to do this, a highly accurate drive system is required.

[0007]

According to a first aspect of the present invention, the light emitted from the light source is used to scan the surface of the document that is reflected or transmitted, and the light reflected or transmitted thereby is collected by the imaging lens. In an image reading device that obtains image information by detecting an electric signal according to the reflectance or transmittance of the document surface as an image signal by scanning the light incident on a photoelectric conversion element, the fixed document surface of the reflection is scanned. A first traveling body is provided, and a second traveling body that scans at a scanning speed of 1/2 of the first traveling body and is provided with a document reading table for a transparent original is provided, and the maximum effectiveness of the transparent original in the sub-scanning direction is provided. The reading length was set to about 1/2 of the maximum effective reading length of the reflection original in the sub-scanning direction.

According to the second aspect of the present invention, the light emitted from the light source is used to scan the surface of the document which is reflected or transmitted, and the reflected or transmitted light is condensed by the image forming lens to be photoelectric conversion element. In the image reading apparatus that obtains image information by detecting an electric signal according to the reflectance or the transmittance of the document surface as an image signal, a first running body that scans the fixed document surface of the reflection is provided. A second traveling body is provided, which scans at half the scanning speed of the first traveling body and is provided with an original reading table for transparent originals. The maximum effective reading width in the main scanning direction and the sub-scanning direction of the transparent originals are provided. The maximum effective reading length of the reflective original is set to about 1/2 of the maximum reading width in the main scanning direction and the maximum effective reading length in the sub-scanning direction.
In addition, the maximum reading density of the transparent original in the main scanning direction is set to about twice the maximum reading density of the reflective original in the main scanning direction.

According to a third aspect of the invention, in the second aspect of the invention, the photoelectric conversion element is used both for reading the transparent original and for reading the reflective original.

According to the invention described in claim 4,
In the invention described in 3, the imaging lens has a zoom function.

[0011]

According to the first aspect of the invention, since the second traveling body that scans at a speed half that of the first traveling body and the original document reading table for the transparent original are integrated, The reading density in the sub-scanning direction can be made twice as high as the reading density of the reflective original, which enables high-quality reading.

According to the invention of claim 2, claim 1
In addition to the effects described above, the reading density in the main scanning direction at the time of reading a transparent original is doubled the reading density at the time of reading a reflective original, so that high-quality image reading can be performed.

In the invention described in claim 3, claim 2
In addition to the effects described above, the photoelectric conversion element is also used during the reading of the transparent original and the reading of the reflective original, so that the cost can be reduced.

According to the invention described in claim 4, in addition to the effects described in claims 1, 2 and 3, since the imaging lens is used for both reading the transparent original and reading the reflective original, the size of the apparatus can be reduced. It is possible to plan.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows the overall configuration of the image reading apparatus. This apparatus scans the original surface of the reflective original 2a or the transparent original 2b by using the light emitted from the light sources 1a and 1b, and the reflected or transmitted light is thereby formed into the imaging lens 3a,
The light is condensed by 3b and made incident on CCD sensors 4a and 4b as photoelectric conversion elements, an electric signal corresponding to the reflectance or the transmittance of the document surface is detected as an image signal, and the detected image signal is an image signal. Image processing is performed using the processing circuit 5.

In such an apparatus, in this embodiment,
It is characterized by the configuration described below.
That is, the first traveling body 6 that scans the fixed reflecting original surface 2a is provided, and the scanning speed v of the first traveling body 6 is 1
The second traveling body 8 which is scanned at a scanning speed of / 2 and is provided with the original reading table 7 for the transparent original 2b is provided. In this case, the first
The traveling body 6 includes a light source 1a and a mirror 10a. The original reading table 7 includes contact glasses 9a and 9b for holding the transparent original 2b from both sides, and a mirror 10.
It is composed of a holding table 11 that fixedly holds b and 10c. The second traveling body 8 includes the original reading table 7 and mirrors 10b and 10c. The first traveling body 6
The second traveling body 8 and the second traveling body 8 are driven by a motor 12.

Here, the maximum effective reading width of the transparent original 2b in the main scanning direction X and the maximum effective reading length of the transparent original 2b in the sub-scanning direction Y are respectively defined as the main scanning direction X of the reflective original 2a.
And the maximum effective reading length in the sub-scanning direction Y are set to about ½, and the maximum reading density in the main scanning direction X of the transparent original 2b is set to the main scanning direction X in the main scanning direction X. It was set to about twice the maximum read density.

In such a configuration, the image processing operation will be described separately for reading the reflective original and reading the transparent original. First, when reading a reflective original, the reflective original 2a set on the contact glass 13 is irradiated with light from the light source 1a, and the reflected light is reflected by the mirrors 10a, 10b, 10c.
Are sequentially reflected by the imaging lens 3a to form an image and CC
It is guided to the D sensor 4a and an original image is formed on the surface thereof. In this case, the light source 1a and the mirror 10a and the mirrors 10b, 1
Since 0c is placed on each of the first and second running bodies 6 and 8, the mirrors 10b and 10c are scanned at a speed half the speed on the light source 1a side scanned by the motor 12, and the reflection original 2a is scanned. Sub-scanning is performed so that the optical path length from the sensor to the CCD sensor 4a is constant. CCD sensor 4
The CCD sensor drive circuit 20 drives and controls a and 4b.

Thereafter, the CCD sensor 4 corresponding to the original image
The output of a is sent to the image signal processing circuit 5, and is guided to the sample hold circuit 15 via the switch circuit 14 to remove the transfer clock component of the CCD sensor 4a, and its output is digitalized by the A / D conversion circuit 16. Convert to signal. This digital signal is applied to the shading correction circuit 1
7, the brightness variation due to the illumination system and the imaging system, the sensitivity variation of the CCD sensor 4a, and the like are corrected.
In this correction, the previously stored data is stored in the correction memory 1
8 is calculated for each read pixel. The image reading output thus obtained can be taken out from the output terminal 19.

When reading the transparent original, the light source 1 is placed on the transparent original 2b set between the contact glasses 9a and 9b.
Illumination light from b is transmitted through the mirrors 21a and 21b, the transmitted light is guided to the CCD sensor 4b through the imaging lens 3b, and a document image is formed on the surface thereof. The second traveling body 8 is the first
Scanning is performed at half the speed of the traveling body 6, and the original reading table for the transparent original 2b is included therein. Therefore, the speed of the transparent original 2b in the reading sub-scanning direction Y is
It is 1/2 times that of the reflective original 2a, and its reading density is twice that of the reflective original 2a. Further, the reading length of the transparent original 2b in the sub-scanning direction Y is approximately 1/2 the reading length of the reflective original 2b in the sub-scanning direction Y. CCD corresponding to the original image
The output from the sensor 4b is then sent to the image signal processing circuit 5 and the same processing as in the case of the transparent original reading described above is performed.

As described above, as is clear from the description of the reading operation of each of the reflective original 2a and the transparent original 2b,
"The size of the transparent original 2b that is generally used is the reflective original 2a.
, And the required reading density is often higher in the transparent original 2b. " Further, the scanning traveling system does not need to be switched between the reading of the reflective original and the reading of the transparent original, and the configuration can be simplified.

Next, a second embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in the first embodiment (see FIG. 1) is omitted, and the same reference numerals are used for the same parts.

Here, the photoelectric conversion element is used both for reading a transparent original and for reading a reflective original. Specifically, one photoelectric conversion element 22 is used instead of the photoelectric conversion elements 4a and 4b of the first embodiment described above.
Is arranged so that both the reading of the transparent original and the reading of the reflective original are performed. Along with this, a mirror 23a whose position can be switched at the position P and a mirror 23b for changing the optical path are newly provided.

In such a structure, the mirror 23a at the position P is moved to read the image forming lens 3 when reading the reflection original.
Image signal processing is performed in a state of being retracted from the optical path from a to the CCD sensor 22. Further, at the time of reading the transparent original, the mirror 23a is arranged at the position P, and the light incident on the imaging lens 3b is further reflected by the mirrors 23b, 23.
Image signals are processed by sequentially reflecting the light by a, guiding it to the CCD sensor 22, and forming a document image on the surface thereof. Therefore, from the above, it is possible to reduce the number of CCD sensors as compared with the above-described embodiment, and thereby to reduce the cost.

FIG. 3 shows the state of the original reading width. In the figure, A is the main scanning direction X on the reflection original surface.
, And B shows the effective read width in the main scanning direction X on the transparent original surface. A: B = 2: 1
Have a relationship. Of the images within these reading widths, the width A
Is imaged by the imaging lens 3a, and the image from the width B is imaged by the imaging lens 3b, and then is formed with the same width on the surface of the photoelectric conversion element 22 which is the imaging surface. ..

Thus, the main scanning direction X of the transparent original reading
The reading width of the original is 1/2 of the reading width in the main scanning direction X of the reflective original reading, but the reading density in the transparent original reading (main scanning direction) is twice the reading density in the reflective original reading. You can Therefore, when transmitting and reflecting, C
Pixels of the CD sensor 22 are used efficiently, and also in the main scanning direction X, "the size of the transparent original 2b that is generally used is smaller than the size of the reflective original 2a, and the required reading density is transparent. It is possible to obtain an image reading apparatus that meets the usage condition that "the original 2b is often higher".

Next, a third embodiment of the present invention will be described with reference to FIG. The description of the same parts as those of the first and second embodiments (see FIGS. 1 and 2) is omitted, and the same reference numerals are used for the same parts.

Here, the image forming lens is provided with a zoom function. Specifically, the above-mentioned imaging lens 3
Instead of a and 3b, one image forming lens 24 having the function of a zoom lens is arranged so that both the reading of a transparent original and the reading of a reflective original are performed. Along with this, the above-mentioned mirrors 23a and 23b and the CCD sensor 22 are used.

With such a structure, when reading a reflection original, the mirror 23a is moved from the mirror 10c to the imaging lens 2.
The image signal is processed in a state of being retracted from the optical path up to 4. Further, when reading the transparent original, the mirror 23 is set to the position P.
The light from the mirror 21b to the mirror 23
The image signals are processed by being sequentially reflected by b and 23a, guided to the CCD sensor 24, and imaged on this surface. In this case, the imaging lens 24 has the same field angle as that of the imaging lens 3a in FIG.
At the time of reading the transparent original, the lens function is switched so as to have the same angle of view as in the case of the imaging lens 3b in FIG.
Therefore, by using the image forming lens 24 having the function of such a zoom lens, it is possible to perform both the reading of the transparent original and the reading of the reflective original, so that the number of parts can be greatly reduced. It is possible to further reduce the size of the device.

Finally, a more applied specific example based on the three embodiments described above will be sequentially described. First, as a first specific example, the maximum reading width of the reflective original 2a is set to about A4 or letter size, and the maximum reading area of the transparent original 2b is set to about 4 inches × 5 inches. As a result, according to the sizes of the transparent original 2b and the reflective original 2a that are generally used, it is possible to read the transparent original 2b up to approximately 4 inches × 5 inches and the reflective original 2a up to approximately A4 or letter size.

As a second specific example, the maximum reading area of the reflective original 2b is set to about A3, and the maximum reading width of the transparent original 2a is set to about 6 inches × 7.5 inches or 6 inches × 8 inches. As a result, the commonly used transparent original 2
b. Depending on the size of the reflection original 2a, it is possible to read up to 6 inches × 7.5 inches or 6 inches × 8 inches with the transparent original 2b and up to about A3 with the reflection original 2a.

As a third specific example, the maximum reading area of the reflective original 2b is set to about A2, and the maximum reading area of the transparent original 2a is set to about 8 inches × 10 inches. This allows
Depending on the sizes of the transparent original 2b and the reflective original 2a that are generally used, it is possible to read up to approximately 8 inches × 10 inches with the transparent original 2b and up to approximately A2 with the reflective original.

As a fourth specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to approximately 600 point per inch for the transparent original 2b and approximately 300 point per inch for the reflective original 2a. .. As a result, according to the read density required for the commonly used transparent original 2b and reflective original 2a, the transparent original 2b reads up to approximately 600 point per inch and the reflective original 2a reads up to approximately 300 point per inch. It becomes possible.

As a fifth specific example, when the maximum reading width is set in the main scanning direction X, the maximum reading density is set to about 800 point per inch for the transparent original 2b and about 400 point per inch for the reflective original 2a. .. As a result, the transparent original 2b can read up to about 800 point per inch and the reflective original 2a can read up to about 400 point per inch according to the reading density required for the commonly used transparent original 2b and reflective original 2a. It becomes possible.

As a sixth specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to about 900 points per inch for the transparent original 2b and to about 450 points per inch for the reflective original 2a. .. As a result, the transparent original 2b can read up to about 900 point per inch and the reflective original 2a can read up to about 450 point per inch according to the reading density required for the commonly used transparent original 2b and reflective original 2a. It becomes possible.

As a seventh specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to about 1200 point per inch for the transparent original 2b and to about 600 point per inch for the reflective original 2a. .. This allows
According to the read density required for the commonly used transparent original 2b and reflective original 2a, the transparent original 2b is approximately 1200
It is possible to read up to approximately 600 point per inch with the reflective original 2a up to point per inch.

As an eighth specific example, when the maximum reading width is set in the main scanning direction X, the maximum reading density is set to about 1600 point per inch for the transparent original 2b and about 800 point per inch for the reflective original 2a. .. This allows
According to the read density required for the commonly used transparent original 2b and reflective original 2a, the transparent original 2b is approximately 1600.
It is possible to read up to about 800 point per inch with the reflective original 2a up to point per inch.

As a ninth specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to about 1800 points per inch for the transparent original 2b and to about 900 points per inch for the reflective original 2a. .. This allows
According to the reading density required for the commonly used transparent original 2b and reflective original 2a, the transparent original 2b is approximately 1800.
It is possible to read up to approximately 900 point per inch with the reflective original 2a up to point per inch.

As a tenth specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to approximately 2400 point per inch for the transparent original 2b and approximately 1200 point per inch for the reflective original 2a. .. As a result, the transparent original 2b has a reading density of about 24 according to the reading density required for the commonly used transparent original 2b and reflective original 2a.
Up to 00 points per inch, almost 12 with reflective original 2a
It is possible to read up to 00 points per inch.

As an eleventh specific example, the maximum reading density when the maximum reading width is set in the main scanning direction X is set to approximately 3200 point per inch for the transparent original 2b and approximately 1600 point per inch for the reflective original 2a. To do. As a result, the transparent original 2b has a reading density of about 32 according to the reading density required for the commonly used transparent original 2b and reflective original 2a.
Up to 00 points per inch, almost 16 for reflective original 2a
It is possible to read up to 00 points per inch.

[0041]

According to the first aspect of the present invention, the light emitted from the light source is used to scan the surface of the original document which is reflected or transmitted, and the reflected or transmitted light is condensed by the imaging lens and photoelectrically converted. In an image reading apparatus that obtains image information by detecting an electric signal corresponding to the reflectance or the transmittance of the document surface as an image signal by making it incident on a conversion element, a first run for scanning the fixed document surface of the reflection. A second traveling body is provided, which is provided with a body, scans at a scanning speed ½ that of the first traveling body, and has a document reading table for a transparent original, and the maximum effective reading length of the transparent original in the sub-scanning direction is set. Since it is set to about 1/2 of the maximum effective reading length of the reflection original in the sub-scanning direction, the second traveling body that scans at a speed half that of the first traveling body in this way,
With the structure in which the original reading table for transparent originals is integrated, the reading density of the transparent originals in the sub-scanning direction can be made twice as high as the reading density of the reflective originals, so that high-quality reading can be performed. Can be done.

According to a second aspect of the present invention, the light emitted from the light source is used to scan the surface of the document that is reflected or transmitted, and the light reflected or transmitted by this is condensed by the imaging lens to be a photoelectric conversion element. In the image reading apparatus that obtains image information by detecting an electric signal according to the reflectance or the transmittance of the document surface as an image signal, a first running body that scans the fixed document surface of the reflection is provided. A second traveling body is provided, which scans at half the scanning speed of the first traveling body and is provided with an original reading table for transparent originals. The maximum effective reading width in the main scanning direction and the sub-scanning direction of the transparent originals are provided. The maximum effective reading length of the transparent original in the main scanning direction and the maximum effective reading length in the sub-scanning direction of the reflective original, and the maximum effective reading length of the transparent original in the main scanning direction. Main scanning direction of the reflection original Since the read density in the main scanning direction is set to approximately twice the maximum read density in the first embodiment, the read density in the main scanning direction at the time of reading the transparent original is set to be twice the read density at the time of reading the reflective original and a high quality image is obtained. It can be read.

According to the invention of claim 3, in the invention of claim 2, the photoelectric conversion element is used both for reading the transparent original and for reading the reflective original. Therefore, in addition to the effect of the second aspect, the number of parts is increased. Can be reduced to reduce the cost of the device.

The invention according to claim 4 is the invention as claimed in claims 1, 2, and 3.
In the invention described in the above, since the imaging lens is provided with a zoom function, in addition to the effects described in claims 1, 2 and 3, it is possible to significantly reduce the number of parts, thereby further reducing the size of the apparatus. Can be done.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an image reading apparatus that is a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing an image reading apparatus that is a second embodiment of the present invention.

FIG. 3 is an optical path diagram showing a state regarding an effective reading width of a reflective original and a transparent original in a main scanning direction.

FIG. 4 is a configuration diagram showing an image reading apparatus which is a third embodiment of the present invention.

[Explanation of symbols]

 1a, 1b Light source 2a Reflective original 2b Transparent original 3a, 3b Imaging lens 4a, 4b Photoelectric conversion element 6 First traveling body 7 Original reading stand 8 Second traveling body 22 Light source conversion element 24 Imaging lens

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Asai 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh Co., Ltd. (72) Masanori Saito 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Inside the Ricoh Company (72) Inventor Yutaka Kaneko 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Toyowa Satomi 1-3-3 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company

Claims (4)

[Claims] 1. A document surface, which is reflected or transmitted, is scanned by using light emitted from a light source, and the reflected or transmitted light is condensed by an imaging lens to be incident on a photoelectric conversion element. In an image reading apparatus that obtains image information by detecting an electric signal corresponding to the reflectance or transmittance of the surface as an image signal, a first traveling body that scans the fixed document surface of the reflection is provided, and the first traveling is performed. A second running body that scans at half the scanning speed of the body and has a document reading table for transparent originals is provided, and the maximum effective reading length of the transparent originals in the sub-scanning direction is set to the maximum in the sub-scanning direction of reflective originals. About 1 / effective reading length
An image reading device characterized by being set to 2. 2. A document surface that is reflected or transmitted is scanned by using light emitted from a light source, and the light reflected or transmitted thereby is condensed by an imaging lens and is incident on a photoelectric conversion element. In an image reading apparatus that obtains image information by detecting an electric signal corresponding to the reflectance or transmittance of the surface as an image signal, a first traveling body that scans the fixed document surface of the reflection is provided, and the first traveling is performed. A second running body that scans at half the scanning speed of the body and has a document reading table for transparent originals is provided, and the maximum effective reading width in the main scanning direction and the maximum effective reading length of the transparent originals in the sub-scanning direction are provided. Are set to about 1/2 of the maximum reading width in the main scanning direction and the maximum effective reading length in the sub-scanning direction of the reflective original, and the maximum reading density in the main scanning direction of the transparent original is set to that of the reflective original. About 2 of the maximum reading density in the main scanning direction An image reading device characterized by being set to double. 3. The photoelectric conversion element is used both for reading a transparent original and for reading a reflective original.
The image reading device described. 4. The image reading apparatus according to claim 1, wherein the image forming lens has a zoom function.