JPH06225081A - Document reader and information processor using same - Google Patents

Abstract

PURPOSE:To provide a document reader, which properly uses emitted light colors of a light source in accordance with the number of gradations and the read speed to cope with various documents, and the information processor using this reader. CONSTITUTION:This document reader which irradiates a document with the light from the light source to read the document by the reflected light is provided with light sources 21R and 21Y having plural kinds of emitted light colors and a means which changes the emitted light colors of light sources, and the emitted light color is switched dependently upon whether an output signal is multi-gradation or binary or in accordance with the document read speed. The information processor like a facsimile using this document reader is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a document reading device for reading the image, and more particularly to a contact image sensor used in a facsimile or a copying machine, and an information processing device using the same.

[0002]

2. Description of the Related Art Conventionally, a contact type multi-chip image sensor using, for example, a short-focus image forming element array is known as a document reading device.

6 to 12 show an example of such a document reading apparatus, FIG. 6 is a perspective view of a conventional contact type multi-chip image sensor, and FIG. 7 is a sectional view thereof.
8 is a perspective view of the sensor substrate, FIG. 9 is a sectional view of the sensor substrate, and FIG. 10 is a perspective view of the LED substrate.
FIG. 11 is a perspective view of a facsimile machine equipped with a contact type multi-chip image sensor, and FIG. 12 is a sectional view thereof.

In such a drawing, a transparent glass plate 201 in contact with the original surface is attached to the upper surface of the housing 200 LE.
The substrate 210 on which the D211 is arranged is provided in the housing 200 at a predetermined angle such that the emitted light 212 of the LED 211 is reflected by the original surface in contact with the upper surface of the transparent glass plate 201.
An optical system 209 that transmits the reflected light 213 of the transparent glass plate 201.
Further, a plurality of line sensors 150 provided on the substrate 190 corresponding to the optical system 209 are provided in the housing 200.

For the optical system, for example, the above-mentioned short-focus image forming element array represented by the trade name "SELHOC lens array" (manufactured by Nippon Sheet Glass Co., Ltd.) is adopted.
The line sensor 150 has a protective film 206 on the substrate 190.
And the base plate 190 is covered with the bottom plate 20 that is engaged with the housing 200.
5 is supported by a rubber plate 207.

End plates 203 are attached to both ends of the housing 200 with screws 204. Further, the housing 200 is provided with a connector 202 for inputting / outputting an external power source such as a facsimile main body and control signals.

As shown in FIGS. 11 and 12, such a contact type multi-chip image sensor has an image sensor unit 1 at the original reading position of a facsimile, for example.
10 is arranged via the fixing metal fitting 109. Here, a document insertion port 103 is provided at the front edge of the facsimile main body 100, and the guide stage 10 of the document insertion port 103 is provided.
A slit 105 is formed in parallel with the slit 4
A guide piece 106 that determines the insertion position of the original is slidably mounted on the sheet 05. In addition, the facsimile main body 10
A keyboard panel 101 and an operation message display unit 107 are arranged on the upper surface of the front part of 0, and a document take-out port 102 is provided immediately after that.

In such a device, the document insertion port 10
The original 118 inserted from No. 3 reaches the feeding roller 108 via the separating piece 117, and from there, the platen roller 116.
And the image sensor 110, and the document is discharged to the document outlet 102. A roll-shaped recording paper 114 is stored in the rear part of the facsimile main body 100, and its end is taken out through the platen roller 115. At the position of the platen roller 115, information is recorded by the recording head 111. Is recorded. In the figure, 112 is a system control board of the facsimile, and 113 is a power supply unit.

[Prior Art Example B] FIG. 15 is a perspective view of a contact image sensor used in a conventional document reading apparatus.
FIG. 16 is a sectional view of the structure. As shown in the figure, a sensor substrate 229 on which a sensor 228 that performs photoelectric conversion and a protective film 230 that protects the sensor 228 are mounted, and the document 9 to be read.
Light emitting diode array 226 for illuminating light
And a lens array 227 for forming an image of the document 92 to be read on the sensor light receiving portion, and the transparent body 22 serving as the reading surface.
4 and 4 are attached to the first frame 221.

The first frame 221 includes a lens array 22.
In order to guide the light from 7 to the sensor light receiving portion, slits 231 are provided over substantially the entire length excluding both ends in the longitudinal direction, so that the sectional shapes are 221a and 221a as shown in FIG.
It is divided into 1b.

The second frame 222 for fixing the sensor substrate 229, the set screw 223 for fixing the lens array 227, and the light emitting die are the means for fixing the respective components at predetermined positions of the first frame 221. Adhesives, double-sided tape, screws, etc. (not shown) for fixing the auto array 226 are required. The transparent body 224 is fixed by the side plate 225.

[Conventional Example C] In a conventional document reading apparatus, a contact image sensor for reading an image in close contact with a document includes an image sensor array, a light source as an illuminating unit for illuminating the document, Conventionally, a configuration having an image forming element for forming an image of reflected light from a document on an image sensor array has been adopted.

An LED element having a plurality of LED chips is used as a light source.

However, the LED element having a central emission wavelength of about 570 nm used for FAX or the like has a drawback that it has a low brightness as compared with other light sources such as a fluorescent lamp and a xenon tube, and in particular, the G4 line has recently become popular. As a result, the information transmission capability is improved, and there is a market demand for a high-speed reading and a high resolution for the contact type image sensor. Therefore, increasing the illuminance of the original reading surface has become a problem.

The conventional method of increasing the illuminance of the original surface when an LED array is used as a light source has been considered to increase the number of LED elements, but the cost increases in proportion to the number of LED elements. There is.

Therefore, conventionally, by providing a light guide plate (light guide plate) for condensing the light of LEDs having a wide light distribution without increasing the number of LED chips, the illuminance up of the document reading surface is increased. I am measuring.

The light guide plate is acrylic (refractive index n≈1.5)
Although the light incident on the incident surface of the light guide plate has a total reflection angle on the side surface of the light guide plate, all the light is emitted from the emission surface, so that the illuminance on the original reading surface is more than double. It is possible to

[Prior Art D] FIG. 29 is a perspective view of a conventional contact image sensor, and FIG. 30 is a sectional view of the construction.

As shown in the figure, the sensor 2 for photoelectric conversion
28 and the sensor substrate 228 on which a protective film 230 for protecting the sensor 228 is mounted, a light emitting diode array 226 of a light source for irradiating the read original 92 with light, and the read original 92.
Array 2 for forming an image of
27 and a transparent body 224 to be the reading surface 93 are attached to the first frame 221 by the second frame 222, the set screw 223, and an adhesive agent (not shown).

The first frame 221 comprises the lens array 22.
In order to guide the light from 7 to the sensor light receiving portion, slits 231 are provided over substantially the entire length excluding both ends in the longitudinal direction, so that the cross-sectional shapes are 221a and 221 as shown in FIG.
It is divided into b.

[0021]

[Problem A] However, in the above-mentioned conventional example A, the red LED having the highest brightness as a light source LED and generally the high spectral sensitivity of the line sensor is used.
When the ED is used, there has been a problem that the seal used for a facsimile transmission original or the like is completely erased.

For this reason, there are many cases where LEDs emitting light colors other than red are used. However, since the brightness and the spectral sensitivity of the line sensor are lower than that of red, there are cases in which multi-gradation is required or the original is read at high speed. There was a problem that sufficient sensor characteristics could not be obtained when trying to do so.

Further, if the brightness of the light source is set in accordance with the case where the original is read at high speed or the case where the multi-gradation output is required, even when the original is frequently read at low speed or binary output, There is a problem that the illuminance on the document surface is unnecessarily increased, and power consumption is wasted.

[Problem B] Further, in the conventional example B, since the light emitting diode array 226 is attached to the first frame 221 with an adhesive, a double-sided tape, a screw, or the like, the time until the adhesive is cured, the light emitting diode array 7 Therefore, there is a problem that the assemblability is deteriorated because a means for holding the position of is required.

Further, when the double-sided tape is used, there is a problem that dust is generated from the end portion and dust is attached to the end portion.

Further, fixing with an adhesive or a double-sided tape makes it difficult to separate the light emitting diode array 226 and the first frame 221, and there is a problem that the light emitting diode array 226 and the first frame 221 cannot be reused. .

Further, the first frame 221 for mounting the screw
There was a problem such as an increase in the cost of parts due to tap processing and screw cost processing.

[Problem C] Also, an LED as in Conventional Example C
In a contact image sensor having a point light source array in which a large number of point light sources such as elements are arranged in a straight line, there is a problem in that the illuminance on the original reading surface causes periodic illuminance unevenness corresponding to each point light source.

This is because the illuminance of the original irradiating portion corresponding to the center of the point light source is high, and the illuminance becomes lower toward the periphery thereof, and the periodical illuminance unevenness is generated by the number of point light sources. become.

In the conventional example, since the light guide plate is provided for the purpose of increasing the illuminance, this periodic unevenness in illuminance is particularly emphasized.

Therefore, in the image processing apparatus using the contact image sensor of the conventional example, particularly in a fax machine or the like which is positioned in a high-grade model and requires gradation of 64 gradations or more, a solid original having a uniform reflection density is used. When read, there is a problem that density unevenness corresponding to the point light source pitch occurs in the sensor array main scanning direction of the output image.

Conventionally, there has been a means for applying a light scattering agent to the incident surface or the exit surface of the light guide plate in order to reduce this periodic illuminance unevenness, but this means that the light collecting effect of the light guide plate is halved. There was a problem.

[Problem D] In the conventional example D, since a plurality of point light sources having light distribution characteristics in the light emitting diode array 226, which is a light source, are arranged in a straight line, the reading surface 93 has a sectional direction. Has a light intensity distribution as shown in Fig. 31,
Further, the light amount distribution is as shown in FIG. 32 in the longitudinal direction. In the figure, 214 is a light source substrate, 215 is a light emitting diode, and 216 is a light source.

In FIG. 31, the original document 92 to be read can be read by the sensor 228 at the point B (line B in FIG. 29).
Strong light is emitted. Further, in FIG. 32, since it is a point light source, it shows that a periodic light amount distribution is taken on the reading line B.

In the future, in order to realize high-speed and high-resolution reading of the contact image sensor, a light source capable of increasing the amount of light in the reading line B and obtaining a uniform light amount distribution is required. The number of light emitting diode arrays 22
There is a problem that the cost of parts 6 increases.

[Object of the Invention] [Object A] The object of the present invention is to use a light source having a plurality of luminescent colors and selectively use the luminescent colors according to the number of gradations, reading speed, etc. It is another object of the present invention to provide a document reading device capable of suppressing waste of power consumption for reading a document at high speed and reading it at low speed.

[Purpose B] Further, as a structure in which a light source substrate such as a light emitting diode array is attached to the frame, the frame and the light emitting diode array can be reused and the assembling property can be improved to improve the assembling performance. It is to provide a document reading device that can be effectively used.

[Purpose C] Further, a document which suppresses the occurrence of illuminance unevenness on the read image generated by the point light source array having the discrete arrangement of the point light sources, and can also use the light converging effect of the light guide plate to measure the illuminance up To provide a reading device.

[Purpose D] Further, by providing a transparent body having a shape of a light guide plate in contact with the original, the light from the light source is condensed in the vicinity of the irradiation portion and the unevenness of the light quantity distribution due to the discrete point light source can be reduced. To provide a device.

[0040]

Means and Actions for Solving the Problem [Means A] As a means for solving the above-mentioned problems, the present invention is a document reading apparatus which irradiates a document with light from a light source and reads the document with the reflected light. In the document reading apparatus, a light source having a plurality of types of light emission colors and a means for changing the light emission colors of the light sources are provided.

Further, depending on whether the output signal is multi-gradation or binary,
It is characterized in that the luminescent color is switched, and the luminescent color is switched according to the document reading speed, and the luminescent color of the light source is red in the multi-gradation output. The invention is characterized in that an electroluminescent element is provided as a light source having the plurality of types of emission colors, and that the light emitting area of the electroluminescent element is changed according to the gradation. The light emitting area of the electroluminescent element is changed according to the document reading speed.

[Operation A] According to the present invention, a light source having a plurality of luminescent colors is used, and the luminescent color is selectively used according to the number of gradations, reading speed, etc. For example, in the case of binary output, a seal stamp is also used. Since a yellow light source can be used for reading and a red light source can be used to secure S / N in the case of multi-tone output, various originals can be dealt with.

Further, when the original is read at high speed, the brightness of the light source is raised, and when reading at low speed, the brightness of the light source is lowered to reduce waste of power consumption.

Further, by using the electroluminescence element, the light emitting area can be easily controlled and the brightness can be easily adjusted.

[Means B] Further, a sensor array for performing photoelectric conversion, a lens array for forming an image on the surface of the document to be read of the sensor light receiving portion, a transparent body to be the reading surface, and light to the document to be read. An original reading apparatus having a light source for irradiating light, a sensor array, a lens array, a transparent body, and a frame to which the light source is attached is characterized in that a groove for fixing the light source is provided in the frame.

Further, the groove portion is provided with a protection member for protecting the substrate of the light source.

The protection member is made of an elastic body.

[Operation B] According to the means B of the present invention, the sensor array, the lens array, the transparent body, and the frame to which the light source is attached are provided with grooves for fixing the light source, and the substrate of the light source is a protective member such as an elastic body. Since the structure is used to fix the light source, the light source can be securely fixed to the frame at the predetermined position in a detachable manner. Further, it becomes possible to easily separate and re-transfer.

[Means C] Further, a sensor array provided with a photoelectric conversion element group, an equal magnification short focus lens array, and at least two or more point light source elements as light sources are arranged linearly on one substrate. In an image sensor having a light source element array and a light guide plate for guiding light from the point light source element array to a document reading surface, the sensor array main scanning direction is provided with a light guide plate having a shape for diffusing light.

Further, a light guide plate having at least one of an entrance surface and an exit surface concave in the main scanning direction of the sensor array is provided for each of the plurality of point light sources of the point light source array.

Further, there is provided a light guide plate in which at least one of the entrance surface and the exit surface has a convex shape in the sensor array sub-scanning direction and a concave shape in the sensor array main scanning direction.

Further, a light guide plate provided with an air lens in the main scanning direction of the sensor array is provided between the incident surface and the emission surface corresponding to each of the plurality of point light sources of the point light source array.

[Operation C] According to the means C of the present invention, at least one of the entrance surface and the exit surface, which is the end portion of the light guide plate, has a concave surface shape at a position corresponding to each point light source in the sensor array main scanning direction. By providing a section or providing an air lens at a position corresponding to each point light source between the incident surface and the emission surface of the light guide plate, the light of the light source is diffused in the sensor array main scanning direction, It is possible to eliminate the uneven illuminance corresponding to the point light source pitch without reducing the illuminance on the reading line.

Particularly when used for a product of multi-gradation output image such as 64 gradations, it is possible to eliminate the density unevenness corresponding to the point light source pitch which occurs in the output image when a uniform density original is read.

[Means D] Further, a sensor array for performing photoelectric conversion, a lens array for forming an image of the document to be read on the light receiving portion of the sensor, a transparent body as a reading surface, and light to the document to be read. An image sensor having a light source for irradiating, a front sensor array, a lens array, a transparent body, and a frame for mounting the light source is provided with a transparent body having a light guide plate-like portion that guides irradiation light from the light source to a document to be read. It has a characteristic document reading device.

Further, a transparent body having a shape in which the angle θ ₁ between the optical axis of the light guide plate and the reading optical axis is smaller than the total reflection angle θ ₀ inside the transparent body is provided.

Further, a transparent body having a shape in which the optical axis is bent at least once by utilizing total internal reflection inside the light guide plate portion is provided.

Further, the irradiation light incident portion from the light source of the light guide plate portion is provided with a lens-shaped transparent body.

Further, the irradiation light incident part from the light source of the light guide plate part is provided with a transparent body having a shape for reducing unevenness of the light amount on the reading surface by the discrete point light sources.

The transparent body is molded with transparent resin integrally with the light guide plate.

Further, the transparent body is integrally formed by bonding the light guide plate portion, the glass and the transparent resin.

[Operation D] According to the means D of the present invention, the light guide plate portion for guiding the irradiation light of the light source to the original to be read is formed on the transparent body in contact with the surface of the original by integrally molding transparent resin or glass and transparent resin. An integrated structure is formed by bonding, etc., and the light is condensed by adjusting the angle θ ₁ between the optical axis of the light guide plate and the reading optical axis and the total reflection angle θ ₀ inside the transparent body to θ ₁ <θ _0. As a result, it is possible to increase the amount of light on the reading line and reduce the unevenness of the light amount distribution.

[0063]

EXAMPLE [Example A1] FIG. 1 shows Example A1 of the present invention.
FIG. 3 is a diagram showing an LED substrate as a light source in FIG. In the figure, 21R is an LED whose emission color is red, and 21Y is an LED whose emission color is yellow, which are arranged alternately. LED
For 21R and 21Y, only the LED 21R is turned on,
Only LED21Y is turned on, or both LEDs
Is electrically connected so that it can be turned on.

When such an LED substrate 20 is incorporated in a contact type multi-chip image sensor as shown in the conventional example and is used for reading a document of a facsimile, for example, the keyboard panel 10 of the facsimile apparatus shown in FIG.
A button for selecting a multi-tone image and a binary image is provided in 1, and when the multi-tone is selected, only the red LED 21R,
Alternatively, both the red LED 21R and the yellow LED 21Y are turned on to read the original, and when the binary value is selected, only the yellow LED 21Y is turned on to read the original.

Normally, most of the originals such as documents and drawings on which the seal stamp has been stamped are sufficiently binary images, and the problem of disappearing the seal stamp can be solved. In addition, as compared with a case of obtaining a multi-tone image, a low illuminance causes no problem when obtaining a binary image. In most cases, a binary image is acceptable for a facsimile document, and therefore it is also effective in reducing power consumption.

[Example A2] FIG. 2 shows Example A2 of the present invention.
2 is a cross-sectional view of the contact type multi-chip image sensor in FIG. 2, and 22 is a light source, which is an example using an electroluminescent element (hereinafter abbreviated as EL element) that emits light by applying an AC voltage. The same configurations as those of the other conventional examples are designated by the same reference numerals and the description thereof will be omitted.

FIG. 3 is a plan view of the EL element 22. In the figure, 23 and 24 are light emitting layers whose emission color is red, 25 is a light emitting layer whose emission color is yellow, and 26 is the light emitting layers 23 and 24. Wiring connected to both back electrodes for controlling light emission, 27 is a light emitting layer 25
Wiring connected to the back electrode that controls the emission of
It is a pin terminal for driving the element 22 from the outside. FIG. 5 is a view showing the cross section of the EL element 22 and the electrical connection to the outside. In FIG. 5, 29 is a package film, 30 and 31 are water catching layers, 32 is a transparent conductive film, and 3 is a transparent conductive film.
3, 34 are light-emitting layers containing a phosphor whose emission color is red, 35
Is a light emitting layer containing a phosphor whose emission color is yellow, 36 is an insulating layer, and 37, 38 and 39 are light emitting layers 33, 34 and 3 respectively.
5 is a back electrode for controlling light emission, 40 is an EL element 2
2 is an AC power source for emitting light, 41 is a back electrode 37,
38 is a switch for connecting the AC power supply 40, and 42 is a switch for connecting the back electrode 39 and the AC power supply 40. Since the back electrodes 37 and 38 for controlling the light emission of the light emitting layers 33 and 34 are connected to the common wiring 26,
Wiring that turns on or off at the same time and only the light emitting layer 35 is independent
Since it is connected to 7, light emission can be controlled independently.

When the original document of the facsimile shown in FIG. 11 is read by the contact type multi-chip image sensor shown in FIG. 2 having such a structure, the multi-gradation image in the keyboard panel 101 is carried out in the same manner as in the embodiment A1. Multi-gradation or binary is selected with the button for selecting a binary image, and in the case of multi-gradation, the light emitting layers 33, 34 or all the light emitting layers 33, 34, 35 are made to emit light, and in the case of binary it is made to emit light. Layer 35
It suffices to emit light only for reading the original.

When the EL element 22 is used as a light source, the area of the light emitting layer can be freely set, so that the brightness of each light emitting layer, the spectral sensitivity of the line sensor 150, and the required gradation are taken into consideration as shown in FIG. The most advantageous area distribution can be achieved. Further, it is more cost effective than the case of using LEDs of a plurality of colors as in Example A1.

[Example A3] FIG. 4 shows Example A3 of the present invention.
FIG. 5 is a plan view of an EL element used as a light source of the contact type multi-chip image sensor in FIG.
0, 51 and 52 are light emitting layers whose light emission can be controlled independently, and 53, 54 and 55 are light emitting layers 50, 51 and 5 respectively.
Wiring connected to a back electrode (not shown) for controlling the light emission of 2 and 56 are pin terminals for driving the EL element from the outside.

An operation of incorporating an EL element having such a structure as a light source of a contact type multi-chip image sensor as in the second embodiment and reading an original by a facsimile as shown in FIG. 11 will be described below.

When sending originals by facsimile, when the number of originals is large, or when there are many users waiting in order, it is necessary to read the originals at high speed, but when the number of originals is small and there is no particular urgency. Does not necessarily need to read at high speed. If the latter is used in many cases, high-speed reading is relatively disadvantageous in terms of power consumption because the document surface illuminance is increased.

Therefore, the keyboard panel 101 of FIG. 11 is provided with buttons for selecting low speed, medium speed, and high speed for reading an original. When the low speed is selected, only the light emitting layer 51 emits light, and when the medium speed is selected, the light emission occurs. Only the layer 50 emits light,
When the high speed is selected, all the light emitting layers 50, 51 and 52 are made to emit light to read the original, and the minimum power consumption can be achieved at each original reading speed. [Embodiment B1] FIG. 13 is a drawing best showing the features of the embodiment B1 of the present invention. It should be noted that the same components as those of the conventional example are denoted by the same reference numerals as those of the conventional structure, and duplicate description will be omitted.

In FIG. 13, a groove 60 slightly larger than the size of the substrate of the light emitting diode array 226 is provided in the first frame 221, and the light emitting diode array 2 is provided in the groove 60.
By inserting 26, it is fixed to the first frame 221. The size of the groove 60 is set to an appropriate size in consideration of variations in the substrate of the light emitting diode array 226.

Further, as an example of means for forming the groove 60 in the first frame 221, since the first frame is conventionally manufactured by extrusion of aluminum, the shape of the groove 60 is provided in the extrusion die. It can be easily formed without increasing the cost of parts.

By adopting such a fixing method, it is easy to remove the assembled parts, and the first frame 221
Also, the light emitting diode array 226 can be reused.

Further, the structure shown in this embodiment can obtain the same effect over the entire length of the contact type image sensor, or in a part of the contact type image sensor and in several places.

[Embodiment B2] FIG. 14 shows an embodiment B2 of the present invention in which a protective member 61 is provided between the first frame 221 and the light emitting diode array 226. As shown in the figure, by providing the protection member 61, the light emitting diode array 226 is provided on the first frame 221.
Can be inserted without damaging the electrical wiring on the substrate of the light emitting diode array 226. Further, if the protective member 61 is made of an elastic body, the light emitting diode array 226 can be surely attached at a predetermined position.

Further, the structure shown in this embodiment can obtain the same effect over the entire length of the contact type image sensor, a part of the contact type image sensor in the longitudinal direction and a few places. [Embodiment C1] An embodiment C1 of the present invention will be described below with reference to FIGS. 17, 18, 19, and 20.

FIG. 17 shows an L with a light guide plate of the embodiment C1 of the present invention.
FIG. 18 is a cross-sectional view of the ED array, and FIG. 18 is a side view.

As shown in FIG. 17, the light entering portion and the light exiting portion 63 of the light guide plate 68 focus light on the reading line of the original surface, so that the sensor array sub-scanning method is a convex lens shape 63.
Has become.

Further, as shown in FIG. 18, in order to diffuse the light of the LED light source 66 in the main scanning direction of the sensor array, the light entrance portion and the light exit portion 64 of the light guide plate 68 are concave lens-shaped 6
4 is set.

As a method of manufacturing the light guide plate 68, a transparent resin such as acrylic resin can be easily manufactured by injection molding.

FIG. 19 is a sectional view of a contact image sensor incorporating the LED array with a light guide plate of the present invention.
Reference numeral 7 represents a read line. FIG. 20 is a top view. As in the conventional case, 92 is the original to be read, 221 is the first frame, and 2 is the second frame.
Reference numeral 24 is a transparent body, 226 is an LED array substrate, 227 is a lens array, 228 is a sensor, and 229 is a sensor substrate.

[Embodiment C2] FIG. 21 shows an embodiment C of the present invention.
22 is a sectional view of the LED array with a light guide plate incorporated in FIG. 2, and FIG. 22 is a side view.

In this embodiment, as shown in FIGS. 21 and 22, a circular hole 70 is formed in the light guide plate 68 at a position corresponding to the LED light source 66.
The light from the LED light source 66 is diffused only in the main scanning direction of the sensor array by opening the window and functioning as an air lens. [Embodiment D1] FIG. 23 is a drawing best showing the features of the embodiment D1 of the present invention. It should be noted that the same components as those of the conventional example are denoted by the same reference numerals as those of the conventional structure, and duplicate description will be omitted.

In FIG. 23, a light guide plate-like shape as shown in the drawing is provided on the light emitting diode array 226 side of the transparent body 84 here. In the figure, reference numeral 85 denotes an incident portion of light from the light emitting diode array 226 which is a light source, and θ
₁ is the angle between the optical axis of the light guide plate and the reading optical axis.

The total reflection angle inside the transparent body 84 is θ
_{If 0} , and θ ₁ is θ ₀ or more (θ ₁ ≧ θ ₀ ),
Since the irradiation light does not reach the outside of the transparent body, that is, the document to be read (not shown), θ ₁ needs to be smaller than θ ₀ (required condition θ ₁ <θ ₀ ).

FIG. 24 shows the light quantity distribution on the reading surface 93 in FIG. 23, which is a reading point B (reading line B in FIG. 29) as compared with FIG. 31 showing the light quantity distribution in the conventional example. The amount of light at is increasing.

[Embodiment D2] FIG. 25 shows an embodiment D2 of the present invention in which the transparent body 84 is provided with a light guide plate shape and the total reflection inside the transparent body is utilized to determine the optical axis of the light guide portion. This is an example of bending once. In the figure, θ ₂ is the angle between the optical axis of the light source from the incident portion 85 and the reflection surface of the light guide portion. In order to utilize the total internal reflection, θ ₂ needs to satisfy θ ₂ <90 ° −θ ₀ . Similar to the theta ₁ is the previous Example D1 theta ₁
<Θ ₀ .

With such a structure, the degree of freedom in setting the position and angle of the light emitting diode array 226, which is the light source, is increased.

[Embodiment D3] FIG. 26 shows an embodiment D3 of the present invention in which a transparent body 84 is provided with a light guide plate shape, and
This is an example in which the incident portion 85 of the light from the light source has a lens shape. In the figure, the light amount at the reading point B (reading line B in FIG. 29) can be further increased by appropriately setting the lens shape of the incident portion 85.

[Embodiment D4] FIG. 28 shows, as Embodiment D4 of the present invention, a transparent body 94 having a light guide plate shape, and
This is an example in which the incident portion 85 of the light from the light source is shaped to reduce the unevenness of the light amount on the reading surface by the discrete point light source.

FIG. 28 is a view best showing the shape of the transparent body 94 of this embodiment, and is a sectional view taken along the line AA of FIG. As shown in the figure, the transparent body 94 is used for the light emitting diode 2
A concave shape is formed at the position of 15, and a convex shape is formed in the middle between the light emitting diodes 215. For this reason,
As shown in FIG. 28, the light amount distribution on the reading line B can be made relatively uniform.

For comparison, FIG. 27 shows the transparent body 84 of Example D1 as a sectional view taken along line AA in FIG.

The light amount distribution in FIG. 27 has a large amount of periodicity and large unevenness in amplitude as in the case of the conventional example, which is similar to that in FIG. 32, but the incident portion 85 is set to an appropriate waveform as shown in FIG. By doing so, it is possible to reduce the unevenness of the light amount on the reading line B.

[0097]

[Effect of the Invention] [Effect A] As described above, as a light source for reading an original, a multi-gradation output and a binary output are used by using a light source having a red emission color and a light source other than red light. By properly using the stamp, the image information of the stamp is not lost at high speed with low power consumption when reading a document in which the stamp is stamped on the document, and sufficient sensor characteristics can be obtained even at multiple gradations.

When an EL element is used as a light source, the balance between multi-gradation and binary illuminance on the document surface can be adjusted by the area of the light emitter.

Further, by causing a plurality of independent light sources to emit light in stages according to the document reading speed, the document can be read with the minimum necessary power consumption even at the low speed reading [Effect B]. By fixing the light emitting diode to the frame by inserting it in the groove provided in the frame, there is no need for auxiliary materials (adhesive, double-sided tape, screws, etc.) for fixing, It is possible to improve and reuse the light emitting diode array and the frame, and the manufacturing cost can be reduced.

[Effect C] In addition, the incident surface, which is the end of the light guide plate of the point light source array housed in the contact image sensor,
Light is diffused from the point light source to the original only in the sensor array main scanning direction by forming a concave shape corresponding to each point light source in the sensor array main scanning direction on at least one of the emission surfaces, or by providing an air lens. The shape has the effect of reducing the illuminance ripple on the document surface due to the point light source, and particularly in the image processing apparatus that requires high gradation,
Due to the illuminance ripple on the document surface, it is possible to obtain the effect of reducing the density unevenness that occurs in an output image of intermediate density.

[Effect D] Further, by providing the transparent body with the shape of a light guide plate, without increasing the light amount of the light source,
It is possible to increase the amount of light in the reading unit, and it is possible to reduce unevenness in the amount of light in the reading unit by appropriately setting the shape of the incident part of the light from the light source.

[Brief description of drawings]

FIG. 1 is a perspective view of an LED substrate of Example A1 of the present invention.

FIG. 2 is a sectional view of a contact type multi-chip image sensor unit of Example A2 of the present invention.

FIG. 3 is a plan view showing a distribution of a light emitting layer of the EL element shown in FIG.

FIG. 4 is a plan view showing a distribution of light emitting layers of an EL device of Example A3 of the invention.

5 is a diagram showing a cross section and an electrical connection of the EL element shown in FIG.

FIG. 6 is a perspective view of a conventional contact type multi-chip image sensor.

FIG. 7 is a cross-sectional view of a conventional contact type multi-chip image sensor unit.

8 is a perspective view of the conventional sensor substrate shown in FIG. 7. FIG.

9 is a cross-sectional view showing a conventional sensor substrate shown in FIG.

10 is a perspective view of an LED (light source) substrate of the conventional example shown in FIG.

FIG. 11 is a perspective view of a facsimile equipped with a conventional contact type multi-chip image sensor unit.

12 is a cross-sectional view of a chain line portion shown in FIG.

FIG. 13 is a configuration sectional view of a contact image sensor of Example B1 of the invention.

FIG. 14 is a configuration sectional view of a contact image sensor of Example B2 of the invention.

FIG. 15 is a perspective view of a conventional contact image sensor.

FIG. 16 is a sectional view showing the configuration of a conventional contact image sensor.

FIG. 17 is a sectional view of a light guide plate of Example C1 of the present invention.

FIG. 18 is a front view of the light guide plate in Example C1 shown in FIG.

19 is a sectional view of a contact image sensor incorporating the light guide plate of Example C1 shown in FIG.

20 is a top view of the contact image sensor shown in FIG. 19. FIG.

FIG. 21 is a cross-sectional view of a light guide plate of Example C2 of the present invention.

22 is a side view of the light guide plate of the embodiment shown in FIG.

FIG. 23 is a cross-sectional view of a structure incorporating a transparent body of Example D1 of the present invention.

24 is a light amount distribution diagram on the reading surface in the embodiment shown in FIG.

FIG. 25 is a cross-sectional view showing a built-in structure of a transparent body according to an embodiment D2 of the present invention in which the optical axis of the light guide section is bent once.

FIG. 26 is a structural cross-sectional view of a transparent body of a light guide section in which the entrance section of Example D3 of the present invention has a lens shape.

27 is a light quantity distribution diagram on the read line of Example D1 shown in FIG. 1. FIG.

FIG. 28 is a light amount distribution chart in the case where the incident portion of Example D4 of the present invention is shaped to reduce light amount unevenness on the reading line.

FIG. 29 is a perspective view of a conventional contact image sensor.

30 is a cross-sectional view of the configuration of the conventional example of FIG.

FIG. 31 is a light amount distribution diagram on a reading surface of a conventional example.

FIG. 32 is a light amount distribution diagram on a reading line of a conventional example.

[Explanation of symbols]

20 LED array substrate 21R Red LED 21Y Yellow LED 22 EL element 23, 24, 33, 34 Red light emitting layer 25, 35 Yellow light emitting layer 26, 27, 53, 54, 55 Wiring 28, 56 EL element pin Terminal 29 Package film 30, 31 Water catching layer 32 Transparent conductive film 36 Insulating layer 37, 38, 39 Back electrode 40 AC power supply 41, 42 Switch 50, 51, 52 Light emitting layer 60 Groove 61 Protective member 63 Light guide plate convex lens shape 64 Conductor Optical plate concave lens shape 66 Point light source 67 Reading line 68 Light guide plate 84 Transparent body with light guide section 85 Light incident part from light source θ ₀ Total reflection angle in transparent body θ ₁ Angle between optical axis of light guide section and reading optical axis θ ₂ Angle between light source optical axis and light guide reflection surface

Claims (22)

[Claims] 1. An original reading apparatus which irradiates an original with light from a light source and reads the original with its reflected light, has a light source having a plurality of types of emission colors, and means for changing the emission color of the light source. A document reading device characterized by: 2. The document reading apparatus according to claim 1, wherein the emission color is switched depending on whether the output signal is multi-gradation or binary. 3. The document reading device according to claim 1, wherein the emission color is switched according to a document reading speed. 4. The document reading apparatus according to claim 1, wherein the light emission color of the light source is red when the multi-gradation output is performed. 5. The document reading apparatus according to claim 1, further comprising an electroluminescence element as the light source having the plurality of types of emission colors. 6. The document reading apparatus according to claim 5, wherein the light emitting area of the electroluminescent element is changed according to the gradation. 7. The document reading apparatus according to claim 5, wherein a light emitting area of the electroluminescence element is changed according to a document reading speed. 8. A sensor array for performing photoelectric conversion, and a lens array for forming an image of an original surface to be read on a sensor light receiving portion,
A document reading apparatus having a transparent body serving as a reading surface, a light source for irradiating the read document with light, a frame for integrally mounting the sensor array, the lens array, the transparent body, and the light source, wherein the frame An original reading device characterized in that a groove for fixing the light source substrate is provided in the document reading device. 9. The document reading apparatus according to claim 8, wherein the groove portion is provided with a protective member for protecting the light source substrate. 10. The document reading apparatus according to claim 9, wherein the protection member is an elastic body. 11. A sensor array provided with a photoelectric conversion element group, an equal magnification short focus lens array, and a point light source element array in which at least two or more point light source elements as light sources are linearly arranged on one substrate. In the document reading device, the document reading device has a light guide plate for guiding light from the point light source element array to a document reading surface.
A document reading device having a shape for diffusing light from the point light source. 12. The light guide plate is characterized in that at least one of an incident surface and an emission surface is formed in a concave shape in the sensor array main scanning direction, corresponding to each of the plurality of point light sources of the point light source array. The document reading device according to claim 11. 13. The document reading apparatus according to claim 11, wherein at least one of the incident surface and the exit surface of the light guide plate has a convex shape in the sensor array sub-scanning direction. 14. The light guide plate is provided with an air lens in the main scanning direction of the sensor array corresponding to a plurality of point light sources of the point light source array between an incident surface and an emission surface. Item 11. The document reading device according to item 11. 15. A sensor array for performing photoelectric conversion, a lens array for forming an image of a document to be read on a light receiving portion of the sensor, a transparent body serving as a reading surface, and a light source for irradiating the document to be read with light. An image sensor having a frame for integrally mounting the sensor array, the lens array, the transparent body, and the light source, wherein the transparent body has a light guide plate that guides light emitted from the light source to a document to be read. A document reading device characterized by: 16. The light guide plate, wherein the angle θ ₁ between the optical axis of the light guide plate and the reading optical axis is smaller than the total reflection angle θ ₀ inside the transparent body (θ ₁ <θ ₀ ). The document reading apparatus according to claim 15, further comprising: 17. The document reading device according to claim 15, wherein the light guide plate has a shape in which the optical axis is bent at least once using total reflection inside the light guide plate. 18. The document reading apparatus according to claim 15, wherein an irradiation light incident portion of the light guide plate from the light source has a lens shape. 19. The light incident part of the light guide plate from the light source has a concave surface in the vicinity of the point light source, has a convex shape between the point light sources, and has uneven light amount on the reading surface by the discrete point light source. 2. A shape that reduces
5. The document reading device according to item 5. 20. The transparent body is molded by transparent resin,
The document reading device according to claim 15, wherein the document reading device is integrated with the light guide plate. 21. The document reading apparatus according to claim 15, wherein the transparent body is bonded to and integrated with the light guide plate. 22. An information processing apparatus comprising the document reading device according to claim 1.