JPH114321A - Document size detecting device and image reading device using the same - Google Patents

Abstract

(57) [Problem] To reduce a detection distance of a document detection sensor for a document in a document size detection device. SOLUTION: A document table on which a document 1 is stacked, an optical carriage 10 movably provided in a predetermined direction along the document table, and presence / absence of the document 1 on the document table provided on the optical carriage 10 Document detection sensors 20a and 20 for detecting
b, 20c, and 20d, a document detection sensor 20e fixedly provided at a position that does not hinder the movement of the optical carriage 10, and detects the presence or absence of the document 1 on the document table, and document detection sensors 20a, 20b, 20c, and 20d. And document detection sensor 20
and a central processing unit 22 that determines the size of the document 1 based on the output signal of e.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document size detecting device used in an image reading device such as an image scanner or a digital copying machine for reading image information of a document and for determining the size of the document.

[0002]

2. Description of the Related Art In recent years, there has been a rapid shift to personalization of image reading apparatuses. Therefore, a reduction in the price of the document size detection device mounted on the image reading device is required.

Here, a document size detecting device in a conventional image reading device will be described.

FIG. 7 is a plan view showing the arrangement of image detection sensors in a conventional document size detecting device, and FIG. 8 is a sectional view of an image reading device using the document size detecting device of FIG.

In FIG. 7, A1 original 1a, A4 portrait original 1b, A4 original 1
c, B4 original 1d, B5 portrait original 1e, B5 original 1f
Is prepared. An optical carriage 10 having a unit for scanning and reading an image on the document 1 is provided so as to be movable along the document 1.

The document detection sensors 2a, 2b, 2c, and 2d are sequentially arranged so as to be orthogonal to the moving direction of the optical carriage 10 and to overlap the document 1 of a predetermined size. ~ 2d
A3 original 1a and B4 original 1 at positions separated from
It is arranged so as to overlap only with d.

As shown in FIG. 8, a document table glass 4 on which a document 1 is loaded is fitted on the upper surface of the image scanner main body 3. A document pressing plate 5 is attached to the platen glass 4 so as to be openable and closable in order to bring the loaded document 1 into close contact with the platen glass 4.

An optical carriage 10 is provided inside the image scanner main body 1 so as to be movable in the scanning direction of the original 1 (arrow A). On the upper part of the optical carriage 10,
A fluorescent lamp 6 for irradiating the original 1 is attached. On the optical path of the reflected light emitted from the fluorescent lamp 6 and reflected by the original 1, a reflecting mirror 7, an imaging lens 8,
Image sensors 9 are sequentially arranged.

As shown in the figure, the above-mentioned original detection sensors 2a to 2e are capable of detecting the original 1 when the optical carriage 10 is in a standby state and not hindering the movement of the optical carriage 10 during scanning, that is, It is arranged below the optical carriage 10.

[0010]

As described above, in the conventional apparatus configuration, since the document detection sensors 2a to 2e are disposed below the optical carriage 10, the document detection sensors 2a to 2e are inevitably provided. The position was far away from the original 1 to be detected.

For this reason, it is necessary to make the detection distance of the document detection sensors 2a to 2e for detecting the presence or absence of the document 1 longer than the height of the optical carriage 10.
There has been a problem in that the light-emitting diodes constituting a to 2e have a large light quantity, a phototransistor has a high sensitivity, and a lens and a frame have high precision, and as a result, the apparatus has a high price.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a document size detection technique capable of shortening the detection distance of a document detection sensor.

[0013]

In order to solve this problem, a document size detecting apparatus according to the present invention is provided with a document table on which documents are stacked, and a movable apparatus in a predetermined direction along the document table. A moving body, first document detecting means disposed on the moving body for detecting the presence or absence of a document on the platen, and fixedly provided at a position which does not hinder movement of the moving body; A second document detecting unit for detecting the presence / absence of the first document and a determining unit for determining a size of the document based on output signals of the first document detecting unit and the second document detecting unit; The detection distance of the original detecting means with respect to the original can be shortened.

In this document size detecting device, the moving body can be an optical carriage for scanning and reading a document. Further, a plurality of first document detecting means may be arranged in a direction orthogonal to a moving direction of the moving body, and a plurality of second document detecting means may be arranged in the moving direction of the moving body.

Further, the first and second original detecting means can be constituted by an optical sensor comprising a light emitting element for irradiating the original with light and a light receiving element for detecting reflected light from the light emitting element. Alternatively, the first document detecting means is a light receiving element for detecting reflected light of the illuminating means for irradiating the document, and the second document detecting means is a light emitting element for irradiating light to the document and a reflected light from the light emitting element. It can be constituted by an optical sensor including a light receiving element for detecting.

The image reading apparatus of the present invention uses such a document size detecting device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to a first aspect of the present invention is directed to a document table on which documents are stacked, a moving body movably provided in a predetermined direction along the document table, and A first document detecting means disposed to detect the presence or absence of a document on the document table; and a second document detection means provided to be fixed at a position not hindering the movement of the moving body and detecting the presence or absence of the document on the document table. An original size detecting device comprising: an original detecting means; and a determining means for determining a size of the original based on an output signal of the first original detecting means and the second original detecting means. Has the effect of shortening the detection distance for.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a document size detecting device in which a moving body is an optical carriage for scanning and reading a document, and a separate moving body is provided. This eliminates the necessity, and thus has the effect of reducing the cost and size of the device.

According to a third aspect of the present invention, in the first or second aspect, a plurality of first document detecting means are arranged in a direction perpendicular to the moving direction of the moving body, and The document detecting means is a document size detecting device arranged in the moving direction of the moving body. Since the moving body does not become large in the moving direction, it has the effect of reducing the cost and size of the apparatus.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the first and second original detecting means are provided by a light emitting element for irradiating light to the original and a light emitting element. This is a document size detection device composed of an optical sensor consisting of a light receiving element that detects reflected light from the inside of the device where the document detection sensor can be easily attached because the document can be detected from behind the transparent platen. It has the effect that it can be installed in

According to a fifth aspect of the present invention, in the second or third aspect, the first document detecting means is a light receiving element for detecting reflected light of the illuminating means, and the second document detecting means is provided. Is a document size detecting device comprising an optical sensor including a light emitting element for irradiating light toward the original and a light receiving element for detecting reflected light from the light emitting element. This has the effect that the original detection sensor can be obtained at lower cost.

According to a sixth aspect of the present invention, there is provided an image reading apparatus using the original size detecting apparatus according to the first, second, third, fourth or fifth aspect.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and redundant description is omitted.

(Embodiment 1) FIG. 1 is a plan view showing an arrangement of a document detection sensor in a document size detection device according to Embodiment 1 of the present invention. FIG. 2 is an image using the document size detection device of FIG. FIG. 3 is a perspective view showing the document size detecting device of FIG. 1 and its peripheral portion, FIG. 4 is a sectional view showing the internal structure of the document detecting sensor of FIG. 1, and FIG. 5 is an image of FIG. FIG. 3 is a schematic diagram illustrating a document detection mechanism in the reading device.

In the case shown in FIG. 1, the documents 1 to be detected include A3 document 1a, A4 portrait document (hereinafter referred to as "A4v") 1b, A4 document 1c, B4 document 1d and B5. Portrait document (hereinafter referred to as "B5v")
1e, B5 original 1f are prepared. Then, an optical carriage (moving body) 10 containing a reflection mirror 7, an imaging lens 8, an image sensor 9 (FIG. 2) and the like for scanning and reading the image of the document 1 is moved along the document 1. It is provided movably. However, the size of the document 1 to be detected can be various, and is not limited to the above type.

Document detection sensor (first document detection means) 2
Reference numerals 0a, 20b, 20c, and 20d are sequentially arranged so as to be orthogonal to the moving direction of the optical carriage 10 and overlap with a document 1 of a predetermined size. A document detection sensor (second document detection means) 20e detects these documents. Sensor 20a
A3 originals 1a and B at positions separated from
Only four originals 1d are arranged to overlap.

As shown in FIG. 2, a document table glass (document table) 4 on which the document 1 is loaded is fitted on the upper surface of the frame 3. Then, the loaded document 1 is placed on the platen glass 4.
A document pressing plate 5 is attached to the document table glass 4 so as to be openable and closable so as to be in close contact with the document table.

As shown in detail in FIG. 3, an optical carriage 10 is provided inside the frame 1 so as to be movable in the scanning direction of the original 1 indicated by an arrow A. A fluorescent lamp (illuminating means) 6 for irradiating the original 1 is provided above the optical carriage 10.
Is attached. A reflecting mirror 7, an imaging lens 8, and an image sensor (hereinafter, referred to as "CCD") are provided on the optical path of the reflected light emitted from the fluorescent lamp 6 and reflected by the original 1.
That. ) 9 are sequentially arranged, and the reflected light is guided to an imaging lens 8 by a reflection mirror 7, and the light image formed by the imaging lens 8 is photoelectrically converted by a CCD 9 to be an electric signal.

As shown in the figure, the above-described original detection sensors 20a to 20d are attached to a position near the original 1 in the optical carriage 10. Therefore, these original detection sensors 20a to 20d are connected to the optical carriage 1
0, the presence or absence of the document 1 in a direction orthogonal to the moving direction is detected. The document detection sensor 20e is arranged below the optical carriage 10 that can detect the document 1 when the optical carriage 10 is in a standby state and does not hinder the movement of the optical carriage 10 during scanning. Therefore, the document detection sensor 20e detects the presence or absence of the document 1 in the moving direction of the optical carriage 10.

The original detection sensors 20a to 20e are connected to a central processing unit (determination means) 22 which receives these output signals and determines the presence / absence and size of the original 1.

The document detection sensors 20a to 20e can be arranged in various ways as long as they can detect the size of the document 1, and are not limited to the above-mentioned arrangement. However, if the document detection sensors 20a to 20d are arranged in the direction orthogonal to the moving direction of the optical carriage 10 as described above, the optical carriage 10 does not increase in the moving direction, so that the apparatus is reduced in cost and size. Can be.

The original detection sensors 20a to 20d are:
Optical carriage 1 that moves simultaneously with optical carriage 10
It is also possible to dispose it on a moving body different from 0. However, if the document detection sensors 20a to 20e are arranged in the optical carriage 10 as in the present embodiment, there is no need to provide a separate moving body, so that the apparatus can be reduced in cost and size. be able to.

Even when the original detection sensors 20a to 20d are provided on the optical carriage 10, the attachment position is preferably a position close to the original 1 for a reason described later, but is not necessarily a position close to the original 1. It is not necessary.

FIG. 4 shows the internal structure of the document detection sensors 20a to 20e. In FIG. 4, original detection sensors 20 a to 20 e include a light emitting diode 11 which is a light emitting element for irradiating light toward the original 1, and a light emitting diode 1.
1 has a phototransistor 12 which is a light receiving element for detecting light reflected by the original 1 and reflected by the document 1. The light emitting diode 11 and the phototransistor 12 are fixed at predetermined positions in the frame 15. Frame 1
The lens 5 is provided with a lens 13 for condensing the light of the light emitting diode 11 on the document 1 and a lens 14 for condensing the reflected light from the document 1 on the phototransistor 12. Accordingly, the light from the light emitting diode 11 is condensed by the lens 13 and irradiates the document 1, and the reflected light from the document 1 is condensed by the lens 14 and received by the phototransistor 12.

By using such reflection type original detection sensors 20a to 20e, the original 1 on the original platen glass 4 is
, The document detection sensors 20a to 20e can be installed inside the frame 3 that can be easily attached.

As shown in FIG. 5, the original pressing plate 5 of the image reading apparatus is rotatably attached to the frame 3 by hinges 17. A white sheet 16 that directly contacts the original 1 and presses it against the original glass 4 is attached to the original pressing plate 5. The document holding plate 5 is provided with a fan-shaped sensor flag 18 that rotates in conjunction with the document holding plate 5. Then, in order to detect the moved position of the sensor flag 18 and to determine the rotation angle of the document pressing plate 5, for example, two photo interrupters 19a,
19b is provided on the movement path of the sensor flag 18. In FIG. 5, in order to simplify the drawing,
The optical carriage 10 is omitted, and accordingly, the document detection sensors 20a to 20e are collectively shown at predetermined positions in the frame 3.

The operation of the document size detecting device constructed as described above and the image reading device using the same will now be described.

In FIG. 5, the original 1 is stacked on the original platen glass 4 with the original pressing plate 5 fully opened. Next, manuscript 1
The document holding plate 5 is rotated by a predetermined amount in the closing direction, which is the direction of the arrow B, in order to hold the document. Then, when the document pressing plate 5 rotates to the position C, which is an intermediate position, the sensor flag 17 linked to the document pressing plate 5 is detected by the photo interrupter 19a. Thereby, the original pressing plate 5
Is between fully open and fully closed.

When the document holding plate 5 is further rotated in the direction of arrow B to a position D where the document 1 is pressed, that is, a fully closed position, the sensor flag 17 is turned on by the photo interrupter 19.
b. That is, it is recognized that the document pressing plate 5 has reached the fully closed position.

Here, when the document holding plate 5 is at the position C (half-open position), if the document 1 having a predetermined reflectance or more is located at a position corresponding to the document detection sensors 20a to 20e, the light from the light emitting diode 11 emits light from the document. The light is reflected by one surface, whereby the phototransistor 12 enters a light-emitting state. When the original 1 is not present or when the original 1 has a certain reflectance or less, the light from the light emitting diode 11 is not reflected, so that the phototransistor 12 is in a light shielding state.

On the other hand, when the original pressing plate 5 is at the D position (fully closed position), there is an original
If there is no light, the light of the light emitting diode 11 is reflected by the original 1 or the white sheet 16 and
Is in a light incident state. When the original 1 has a reflectance equal to or lower than a predetermined value, the light from the light emitting diode 11 is not reflected, so that the phototransistor 12 is in a light shielding state.

Accordingly, the presence / absence of the document 1 is determined as shown in (Table 1) based on the four types of combinations of light input and light blocking of the phototransistor 12 at the C position and the D position.

[0043]

[Table 1]

According to this, it is possible to determine the presence / absence of the document 1 even in the case of a color document or a document 1 having a picture with a significantly different reflectance.

When the determination of the presence or absence of the document 1 is performed for the document detection sensors 20a to 20e, the size of the document 1 can be determined as shown in (Table 2).

[0046]

[Table 2]

The detection of the presence or absence of the original 1 by the original detection sensors 20a to 20e and the determination of the size of the original 1 based on these determinations are performed by the central processing unit 22 based on the output signals of the original detection sensors 20a to 20e. Done.

Here, as described above, the document detection sensor 2
Since the reference numerals 0a to 20d are provided in the optical carriage 10, the detection distance of the document detection sensors 20a to 20d with respect to the document 1 can be shortened. Thus, the light-emitting diode 11 with a large amount of light and the phototransistor 1 with high sensitivity
2. It is not necessary to use high-precision lenses 13, 14, etc., so that the original detection sensors 20a to 20d can be obtained at a low cost, and the apparatus can be compared with a case where the detection distances of all the original detection sensors 20a to 20e are long. The price can be reduced.

After the size of the original 1 is determined, the optical carriage 10 moves in the direction of arrow A based on the detected size of the original 1, and the entire surface of the original 1 is read.

(Embodiment 2) FIG. 6 is a perspective view showing an original size detecting apparatus according to Embodiment 2 of the present invention and its peripheral portion.

In the second embodiment, document detection sensors (first document detection means) 21a, 21b, 21c,
The configuration of 1d is different from that shown in the first embodiment.
The configuration and the size detection operation at other portions including the document detection sensor 20e are the same as those of the first embodiment.

Here, as shown in FIG. 6, the original detection sensors 21a to 21d arranged on the optical carriage 10 are phototransistors as light receiving elements for detecting the reflected light of the fluorescent lamp 6 irradiating the original 1. Therefore, the fluorescent lamp 6 also performs the same function as the light emitting diode in the first embodiment, and the original detecting mechanism includes the fluorescent lamp 6 and the original detecting sensors 21a to 21d.

In the document size detecting device having such a configuration, the light emitted from the fluorescent lamp 6 is reflected by the document 1 and received by the document detection sensors 21a to 21d. In the document detection sensor 20e, a phototransistor receives reflected light emitted from the light emitting diode provided therein to the document 1. Then, the central processing unit 22 is operated in the manner described in the first embodiment.
Determines the size of the original 1.

In the second embodiment, the original detection sensors 21 a to 21 a provided in the optical carriage 10 are provided.
Since only the light receiving element 21d receives the reflected light from the fluorescent lamp 6, the detection distance to the document 1 can be shortened, and a dedicated light emitting element is not required. 21d can be obtained at a lower cost.

[0055]

As described above, according to the present invention, since the first document detecting means is provided in the movable body, the detection distance of the first document detecting means with respect to the document can be shortened. That is, an effective effect is obtained.

As a result, it is not necessary to use a large light-emitting diode, a high-sensitivity phototransistor, a high-precision lens, and the like for the first document detecting means.
An effective effect that the original detecting means can be obtained at low cost can be obtained. Further, the number of the document detection units having a long detection distance can be reduced, and an effective effect that the price of the apparatus can be reduced can be obtained.

Further, if the movable body is an optical carriage and the first document detection sensor is disposed in the optical carriage, it is not necessary to provide a separate movable body, so that the apparatus can be reduced in cost and size. An effective effect of being able to achieve is obtained.

If a plurality of first document detection sensors are arranged in a direction orthogonal to the moving direction of the moving body, the moving body does not become large in the moving direction, so that the apparatus can be reduced in cost and size. Effective effects can be obtained.

If a reflection type sensor composed of a light emitting element and a light receiving element is used as the document detection sensor, the document can be detected from the back side of the transparent document table. This is an effective effect of being able to be installed in a computer.

If the first document detection sensor is constituted by a light receiving element for receiving the reflected light from the illumination means, a dedicated light emitting element is not required, and the first document detection sensor can be obtained at a lower cost. That is, an effective effect is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement of a document detection sensor in a document size detection device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an image reading apparatus using the document size detecting device of FIG. 1;

FIG. 3 is a perspective view showing the document size detecting device of FIG. 1 and its peripheral portion;

FIG. 4 is a sectional view showing the internal structure of the document detection sensor of FIG. 1;

FIG. 5 is a schematic diagram illustrating a document detection mechanism in the image reading apparatus of FIG. 2;

FIG. 6 is a perspective view showing a document size detecting device according to a second embodiment of the present invention and a peripheral portion thereof;

FIG. 7 is a plan view showing the arrangement of an image detection sensor in a conventional document size detection device.

FIG. 8 is a cross-sectional view of an image reading apparatus using the document size detecting device of FIG. 7;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 document 4 document table glass (document table) 6 fluorescent lamp (illuminating means) 10 optical carriage (moving body) 11 light emitting diode (light emitting element) 12 phototransistor (light receiving element) 20a document detecting sensor (first document detecting means) 20b Document detection sensor (first document detection means) 20c Document detection sensor (first document detection means) 20d Document detection sensor (first document detection means) 20e Document detection sensor (second document detection means) 21a Document Detection sensor (first document detection unit) 21b Document detection sensor (first document detection unit) 21c Document detection sensor (first document detection unit) 21d Document detection sensor (first document detection unit) 22 Central processing Device (judgment means)

Claims (6)

[Claims] 1. A document table on which documents are stacked, a moving body movably provided in a predetermined direction along the document table, and a presence / absence of the document on the document table provided on the moving body. A first document detecting means for detecting the movement of the moving body, and fixedly provided at a position which does not hinder the movement of the moving body;
Second document detecting means for detecting the presence or absence of the document on the document table; determining means for determining the size of the document based on output signals from the first document detecting means and the second document detecting means And a document size detecting device. 2. The document size detecting device according to claim 1, wherein the movable body is an optical carriage that scans and reads the document. 3. The apparatus according to claim 1, wherein a plurality of the first document detecting means are arranged in a direction orthogonal to a moving direction of the moving body, and the second document detecting means is arranged in a moving direction of the moving body. 3. The document size detecting device according to claim 1, wherein: 4. The apparatus according to claim 1, wherein the first and second document detecting means are light sensors each including a light emitting element for irradiating the document with light and a light receiving element for detecting reflected light from the light emitting element. 4. The document size detecting device according to claim 2, wherein: 5. The first document detecting means is a light receiving element for detecting reflected light of an illuminating means for irradiating the document, and the second document detecting means is a light emitting element for irradiating light to the document. 4. The original size detecting device according to claim 2, wherein the optical sensor comprises an optical sensor comprising a light receiving element for detecting light reflected from the light emitting element. 6. An image reading apparatus using the document size detecting apparatus according to claim 1, 2, 3, 4, or 5.