JP2002148730A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image reader thin and small-sized by making the height of an optical read part including a light source small. SOLUTION: The image reader equipped with a platen where an original is mounted, an irradiation part which irradiates the original mounted on the platen with light, a 1st mirror which reflects the reflected light generated by reflecting the irradiation light from the irradiation part by the original surface in a specific direction, a 2nd mirror which is arranged where the reflected light from the 1st mirror is reflected across the optical path between the original surface and 1st mirror, a lens unit which converges the reflected light from the 2nd mirror, and a linear image sensor which converges the reflected light from the 2nd mirror is characterized by that part of both or one of the irradiation part and 1st mirror is in the optical path connecting the 2nd mirror and the outer periphery of the lens unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for optically reading a document and outputting image data, and more particularly to an image reading apparatus in which reflected light from the surface of a read document is crossed using a plurality of reflecting means. The present invention relates to an image reading device configured to allow a linear image sensor to receive light via a lens unit.

[0002]

2. Description of the Related Art An image reading apparatus is configured to optically scan an image on a document, convert the image into electronic data, and then transmit the electronic data to an image forming apparatus such as a personal computer, a facsimile or a copying machine. I have.

[0003] The image data reading method of such an image reading apparatus includes a stationary document reading method in which an optical reading system moves a document placed on a platen made of transparent glass and acquires image data of the document. And a so-called sheet using an automatic document feeder (hereinafter referred to as "ADF") for reading image data of a document sheet conveyed by separating document sheets stacked on a document tray one by one. There is a moving document reading method called a through method.

[0004] In the case of the stationary original reading system, a carriage on which at least a light source unit and a reflecting means are mounted moves along the platen surface in a predetermined direction (sub-scanning direction) below the platen surface to read the original image. read. In the case of the sheet-through reading method, the document is read while the carriage is stopped at a predetermined reading position.

[0005] In an image reading apparatus of an optical reduction system using a linear image sensor such as a CCD, in any of the reading methods, a light source irradiates light to a document surface through a platen so as to be directed vertically below the platen surface. The first mirror reflects the reflected light coming out to the predetermined direction below the platen surface (hereinafter, this is referred to as a “first optical path”), and then the second mirror transmits the reflected light to the predetermined direction below the platen surface. The light is reflected in a direction opposite to the direction (hereinafter, referred to as a “second optical path”), and the reflected light is condensed by a lens unit installed there to form an image on a linear image sensor. Make up. As a result, the first optical path and the second optical path intersect at a substantially right angle, the light source is on the platen side (upper side) of the second optical path, the first mirror is on the opposite side (lower side), Each of them is arranged. An example of the prior art employing such a configuration is disclosed in Japanese Patent Application Laid-Open No. 58-467.
No. 64 is cited.

Further, Utility Model Registration Publication No. 2548078
In the publication, a light source and a first mirror are vertically moved below a platen surface, reflected light from the first mirror is reflected by a second mirror, and the reflected light is passed through a slit of a shading plate. An image reading device configured to guide an image pickup device disposed at a position facing a second mirror is disclosed. Further, Japanese Patent Publication No. 2899140 discloses that
An optical reading system using two mirrors is disclosed.

[0007]

However, in such a conventional image reading apparatus, the thickness (height size) of the apparatus does not impede the optical path region between the second mirror and the condenser lens and the light source that does not obstruct the optical path region. In addition, only the space occupied by the first mirror is required, which is a factor that hinders the reduction in thickness and size of the image forming apparatus.

Further, in the conventional example described in JP-A-58-46764, since the distance between the second mirror and the lens unit is smaller than the length of the light source unit in the optical axis direction, the light source unit protrudes downward. It has been difficult to reduce the size of the device in the height direction. Further, Patent Publication No. 289
In the configuration in which three mirrors are arranged as in JP 9140, it is more difficult to reduce the size of the apparatus in the height direction.

SUMMARY OF THE INVENTION The present invention has been made to solve the problem of the conventional image reading apparatus, and the size of the optical reading section including the light source in the height direction is made smaller (thinner). It is an object of the present invention to realize a reduction in thickness and size.

[0010]

In order to achieve the above object, the present invention provides a platen on which an original is placed, an irradiator for irradiating light to the original placed on the platen, A first mirror for reflecting the light reflected by the original surface in a predetermined direction, and a position for reflecting the reflected light from the first mirror across an optical path between the original surface and the first mirror An image reading apparatus, comprising: a second mirror, a lens unit that collects light reflected from the second mirror, and a linear image sensor that photoelectrically converts image light read from the lens unit. It is an object of the present invention to provide an image reading apparatus in which both or a part of one or both of the first mirror and the first mirror enter a position inside an optical path connecting the outer periphery of the lens unit with the second mirror.

The present invention is particularly applicable to a so-called one-carriage type image reading apparatus including a platen on which a document is placed and a carriage moving along the lower surface of the platen. A carriage configured to irradiate the document placed on the platen with light; a first mirror configured to reflect light reflected from the surface of the document by irradiation light from the irradiation unit in a predetermined direction; and the first mirror. A second mirror disposed at a position for reflecting light reflected from the document surface across an optical path between the document surface and the first mirror, a lens unit for condensing light reflected from the second mirror, and the lens unit A linear image sensor that photoelectrically converts the image light read from the lens unit, and both or both of the irradiation unit and the first mirror are partially moved from the second mirror to the lens unit. Characterized in that it is arranged at a position entering the inside of the optical path connecting the outer periphery.

Here, the irradiating section is arranged on the side of the second mirror so as not to obstruct the optical path between the original surface and the first mirror. This prevents the light source from interfering with the first optical path.

Further, the effective light receiving area of the lens unit extends in the main scanning direction of the linear image sensor. This is because the lens unit is
A plurality of lenses and an aperture member are supported by a frame, and the aperture member is achieved by having a slit-shaped opening long in the main scanning direction corresponding to an effective light receiving area of the lens unit.

By the way, both the irradiating portion and the first mirror and / or a part of any one of the irradiating portions and the first mirror are disposed at a position to enter an optical path connecting the outer circumference of the lens unit from the second mirror. Is disposed outside the optical path passing through the opening.

In the image forming apparatus according to the present invention, a light amount in a longitudinal direction of the light source is adjusted between the first mirror and the lens unit or between the lens unit and the linear image sensor. A shading member provided with an opening of
Both or both of the irradiating unit and the first mirror disposed at a position to enter the inside of the optical path connecting the outer periphery of the lens unit from the mirror are located outside the optical path passing through the opening of the shading member. Placed in

With such a configuration, the height of the optical reading carriage and, consequently, the size of the image reading apparatus incorporating the same can be reduced. This is due to the fact and result that image data of the same quality as that obtained when the total amount of light is received can be obtained without necessarily causing the total amount of light reflected from the original surface to enter the photoelectric conversion element array of the linear image sensor. Based.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the image reading apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view illustrating an external configuration of a front surface of an image reading apparatus according to an embodiment of the present invention. In FIG. 1, this example is an image processing apparatus 100 of an in-body discharge type.
Has a copying function and a facsimile function, etc., photoelectrically converts the read image light of the read document into image data, and outputs the image data by image processing (screen display or print output)
The digital multifunction peripheral is configured to perform

The image processing apparatus 100 shown in FIG.
In addition to an automatic document feeder (ADF) 102 mounted as an option on the upper part of the printer 101, a paper feed table 103 mounted as an option on the lower part of the main body 101 is provided.

In the main body 101, an image forming apparatus (image forming unit) 1 is disposed substantially at the center thereof.
The paper feed unit 2 is provided below the printer. An image reading device (scanner unit) 3 is provided above the image forming apparatus 1. A space between the image reading device 3 and the image forming device 1 is defined, and a lower portion of the space serves as a paper discharge unit 4. The paper discharge section 4 is configured to discharge and place the paper on which the contents of the document are copied. Although the paper supply unit 2 is illustrated as having a two-stage paper supply cassette 21, it may have a configuration of one or three or more stages as needed.

FIG. 2 is a front view showing the internal configuration of the main part in the front configuration of FIG. Referring to FIGS. 1 and 2,
In the paper feed unit 2 disposed below the image forming apparatus 1, for example, a photosensitive drum 5 made of an organic photosensitive body is provided in the image forming apparatus 1. Around the photosensitive drum 5, a charging charger 6 for performing a charging process on the surface of the photosensitive drum 5
In addition, an exposure device 7 for irradiating the photosensitive drum 5 with laser light to image information and a developing device 8 for visualizing (developing) an electrostatic latent image on the photosensitive drum 5 are arranged.

Further, around the photosensitive drum 5, a transfer roller 9 for transferring a toner image on the photosensitive drum 5 to a sheet, and a transfer roller 9 for removing and collecting residual toner on the photosensitive drum 5 are provided. A cleaning device 10 is provided. These function as a so-called electrophotographic processing unit.

Further, in the image forming apparatus 1, a fixing device 11 for melting and fixing the toner image on the sheet after the image transfer by heat is disposed downstream of the electrophotographic process unit in the sheet conveyance. ing.

The two-stage paper cassette 21 stores paper of different sizes or papers of different orientations. In the paper feed cassette 21, a bottom plate 22 for lifting the leading end of the paper to a pull-out roller 23 is attached. The sheet pulled out of the cassette by the pull-out roller 23 is delivered to the registration roller 14 via the delivery roller 24. The paper is fed from the manual feed tray 16 to the registration roller 14 in some cases. The manual feed tray 16 is supported by a hinge structure on the side of the apparatus housing 15 of the image forming apparatus 1. That is, it is mounted so that it can be opened and closed freely.

The image reading device 3 converts an analog image signal read from a document into a digital image and performs image processing. On the basis of the image-processed data, light emission driving of an exposure unit such as a semiconductor laser (not shown) constituting the exposure device 7 is performed. Then, after the laser light is reflected by the polygon mirror, the laser light is further reflected by the mirror and irradiated onto the photosensitive drum 5. This irradiation forms an electrostatic latent image on the photosensitive drum 5.

The sheet having passed through the fixing device 11 is carried out to the discharge section 4 through a plurality of conveying rollers 51, 52, 53. The discharge section 4 is provided with a paper discharge tray 40, and the paper discharge tray 40 is provided with a cover 41 that can be opened and closed about a shaft 41a. By opening and closing the cover 41, an inspection work in maintenance inside the image forming apparatus 1 can be performed.

Further, support sections 61 and 62 are provided on the paper discharge section 4 so as to protrude upward in the figure, and the image reading apparatus 3 is held at the upper section in the figure by the support sections 61 and 62. For this reason, in the image reading device 3, the entire left end of the bottom surface is joined to the end face of the support portion 61, and the right end depth is joined to the end face of the support portion 62.

The automatic document feeder 102 includes a document tray 8
1, a pickup roller 82 is provided, and a paper feed roller 83 and a separation roller 84 are provided. Further, the automatic document feeder 102 is provided with a transport roller 86 together with a registration roller 85, and a paper discharge tray 88 together with a paper discharge roller 87.

The automatic document feeder 102 having such a configuration is attached to the back side of the image reading device 3 via a hinge so as to be freely opened and closed. FIG. 3 is a top view illustrating a configuration of the image reading device 3, and FIG. 4 is a side view illustrating a configuration of the image reading device 3.

As shown in FIGS. 1 to 4, the image reading apparatus 3 includes a housing 1 for supporting platens 31 and 32.
Along with 24, a guide shaft 140 that is inserted into a hole provided on one end side of the carriage 126 and supports the carriage 126 is provided. Further, this image reading device 3 is provided with a pulse motor 142 together with a guide rail 141 supporting the other end of the carriage 126, and a pulley 143 and a timing belt 144.
Is provided.

The image reading device 3 includes a pulley 1
45, the pulleys 146, 147 and the timing belt 1 coupled to the coupling portion 149 of the carriage 126.
48 are provided.

The carriage 126 is provided with an irradiating section 153 having a light receiving opening 152 together with a light source 129, a reflecting plate 150 and a light shielding plate 151. A reflecting first mirror 130 is provided. The carriage 126 has a second mirror 131 that reflects the reflected light from the first mirror 130 in a direction along the platen 31, and a plurality of lenses and an aperture member that collects the reflected light from the second mirror 131. And a lens unit 132 having a cylindrical shape or a rectangular tube shape.

Further, the carriage 126, together with a shading plate 154 disposed before (or after) the lens unit 132, receives light from the lens unit 132 whose structure will be described in detail later. A linear image sensor 133 and a substrate 155 to which the linear image sensor 133 is attached are provided.

FIG. 5 is a side view showing a main part of the image reading apparatus 3 shown in FIG. In FIG. 1 to FIG.
The distance 53 and the first mirror 130 overlap the distances T1 and T2 in the effective light receiving region R of the lens unit 132 in a direction perpendicular to the optical axis P with respect to the lens unit 132, respectively.

The distance L between the second mirror 131 and the lens unit 132 is determined by the distance between the reflecting portion 153 and the first mirror 1.
The length is set to be larger (the interval is wider) than the lengths L1 and L2 in the direction of the optical axis of 30, and the irradiation unit 153 and the first mirror 130 do not block the effective light between the second mirror 131 and the lens unit 132. The area is protrudingly arranged. That is, the irradiation unit 153 is attached such that the lowermost end 153 a on the optical axis P side is below the upper surface 132 a of the lens unit 132 and above the effective light receiving area R of the lens unit 132.

On the other hand, the first mirror 130 has its upper end 13
0a is mounted above the lower surface 132b of the lens unit 132 and below the effective light receiving area R of the lens unit 132.

FIG. 6 is a diagram for explaining a reading state of the image reading device 3, and FIG. 7 is a diagram for explaining scanning of the linear image sensor 133 in a reading state of the image reading device 3. FIG. 8 shows the lens unit 1.
It is sectional drawing which shows the detailed internal structure of 32.

Referring to FIG. 6A, the image reading light (reflected light) in the width direction of the original M (for example, the narrow width direction when A4 size paper is used for vertical and horizontal writing) is passed through the lens unit 132. Image sensor 13 shown in FIG.
The light is incident on a third elongated reading unit (photoelectric conversion element array) 133a. The image sensor 133 reads out this incident light by a drive pulse and outputs the photoelectric conversion signal (binary data). That is, reading is performed by main scanning (X direction).

FIG. 6B is a diagram viewed from the direction of the arrow (y) in FIG. 6A, and shows a case where the original M is used in the vertical width direction (for example, when A4-size paper is used for vertical horizontal writing). (A wide width direction). That is, reading by sub-scanning (Y direction).

The lens unit 132 is provided with an aperture member 132s for limiting irregular reflection of image reading light (reflected light), which will be described later. In addition, in front of the lens unit 132 (or after the lens unit 132), a shading plate 154 in which the arrangement is performed is provided as described below.

Referring to FIG. 8, the lens unit 132
Has a plurality of lenses supported by a frame 132f. An aperture member 132s is provided between the plurality of lenses.

FIG. 9 is a front view for explaining an opening in the shading plate 154. The opening 154a with the shading plate 154 shown in FIG. 9A is particularly formed so that the width of the end is wider than the center. This is because the light intensity distribution of the light source 129 in the longitudinal direction is higher (brighter) in the central portion than in the portion corresponding to the end of the opening 154a. That is, the width of the dark part of the light source 129 is increased and the width of the bright part is reduced.

As a result, the unevenness of the light amount in the longitudinal direction of the light source 129 is compensated (corrected), and the reading unit (photoelectric conversion element array) 13 is provided to the linear image sensor 133.
The reflected light is incident on 3a with a uniform light amount distribution.

The shading plate 154 shown in FIG.
Has an opening 1 in which only one (upper part in the figure) is curved
54r are formed. Its function is the same as that of the opening 154a with the shading plate 154 shown in FIG.

The shading plate 154 shown in FIG.
Has an opening 15 in which only the lower part in the figure is curved.
4t is formed. Its function is the same as that of the opening 154a with the shading plate 154 shown in FIG.

The different openings 154a, 154r, 1
The selection of the 54t shading plate 154 depends on the light source 129.
Is determined based on the characteristics of the lens unit 132 and the linear image sensor 133 together with the illuminance and the reflection plate 150 and the light shielding plate 151. In addition, this shading plate 1
The illumination unit 153 and the first mirror 130 are arranged at a position where the optical path formed by the opening 154a with the illumination unit 154 is not blocked.

Next, a reading state based on the above-described configuration and function will be described. FIG. 10 is a diagram for explaining functions corresponding to the configuration shown in FIG. 5 and 10, the effective light receiving region R of the lens unit 132 extends in the main scanning direction of the linear image sensor 133. The first mirror 130 reflects the light reflected at right angles from the document to the second mirror 131 at an acute angle.
The irradiating unit 153 controls the light source 129 to move the original
The second mirror 1 than the optical path (light receiving opening 152) between
31 is provided.

Therefore, as shown in FIG.
Only the light shielding member 151 is provided on the side of the lens unit 132 from the light receiving opening 152 of the third unit 3, and the irradiation unit 153 can be arranged as close to the lens unit 132 as possible. For this reason, the second mirror 131 is also connected to the lens unit 13.
2, the carriage 126 can be shortened.

On the other hand, the light source 129 is connected to the light receiving opening 1.
If it is arranged closer to the lens unit 132 than to 52, the irradiation unit 153 must move to the second mirror 131 side,
Since the entire optical path length is constant, the second mirror 131 must also be moved away from the lens unit 132. For this reason, the size of the carriage 126 becomes longer, and the entire image reading device 3 becomes larger. The present invention solves this problem.

As shown in FIG. 2, the image reading device 3 includes an image processing board 121, a power supply device 122, and a cooling device 123 such as a fan for lowering the mounting surface.
24 is housed in a bulging housing portion 125 provided on the bottom surface. This makes it possible to reduce the size (thin structure) of the accommodation portion 127 of the carriage 126 in the height direction. Therefore, a step is formed on the bottom surface of the housing 124, and the evacuation portion 128 when the cover 41 is opened below the housing portion 127.
Is formed.

On the other hand, as shown in FIG.
Of the housing 124 by the partition member 120.
7 and a second storage portion 125. Thereby, the influence of the heat in the second storage portion 125 on the first storage portion 127 in which the carriage 126 is stored is reduced.

In this embodiment, the image reading device 3
Can be attached to and detached from the image forming apparatus 1, the image reading device 3 is placed on a desk or the like, and can be used as a device capable of reading a document in this state. For this reason, a leg 134 is provided at the right end so that it can be placed horizontally.

Further, in this embodiment, the description has been given of the carriage type image reading apparatus in which the reading section moves. However, the present invention is applicable to an image reading section in which the image reading section is fixed like a facsimile machine. Needless to say.

As described above in detail, according to the present invention, both the irradiating section and the first mirror or a part of any one of the irradiating section and the first mirror is provided inside an optical path connecting the second mirror to the outer periphery of the lens unit. By arranging the optical reading carriage at a position where the optical reading carriage is inserted, the size and height of the optical reading carriage and, consequently, the image reading apparatus incorporating the optical reading carriage can be reduced in thickness and size.

[Brief description of the drawings]

FIG. 1 is a front view showing an external configuration of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a front view showing an internal configuration of a main part of the configuration of the image reading apparatus of FIG. 1;

FIG. 3 is a top view illustrating a configuration of the image reading apparatus illustrated in FIG. 1;

FIG. 4 is a side view illustrating a configuration of the image reading apparatus illustrated in FIG. 1;

FIG. 5 is a side view illustrating a configuration of a main part of the image reading apparatus illustrated in FIG. 4;

FIG. 6 is a diagram illustrating a reading state of the image reading apparatus according to the embodiment. (A) shows the main scanning (X
Direction). (B) shows a reading state of the document by sub-scanning (Y direction).

FIG. 7 is a diagram for explaining scanning by the linear image sensor in the embodiment.

FIG. 8 is a cross-sectional view illustrating a detailed internal configuration of a lens unit according to the embodiment.

FIG. 9 is a front view for explaining an opening of the shading plate in the embodiment. (A) has shown the opening part which both upper and lower curves in the figure. (B) shows an opening whose upper part is curved in the figure. (C) shows an opening whose lower part in the figure is curved.

FIG. 10 is a diagram for explaining functions in the configuration shown in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 image forming device 3 image reading device 31, 32 platen 100 image reading device 102 automatic document feeder 126 carriage 129 light source 130 first mirror 131 second mirror 132 lens unit 132s aperture member 133 linear image sensor 133a reading unit (photoelectric conversion element) Row) 150 Reflecting plate 151 Light shielding plate 152 Light receiving opening 153 Irradiation unit 154 Shading plate 154a, 154r, 154t Opening

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/107

Claims (8)

[Claims] A platen on which a document is placed; an irradiating section for irradiating the document placed on the platen with light; and a light reflected from the document surface by the irradiation light from the irradiating section in a predetermined direction. A first mirror for reflecting light, a second mirror disposed at a position for reflecting light reflected from the first mirror across an optical path between the document surface and the first mirror, and light reflected from the second mirror A lens unit that collects light, and a linear image sensor that photoelectrically converts image light read from the lens unit, wherein one or both of the irradiation unit and the first mirror are provided. An image reading device, wherein the unit is disposed at a position to enter an inside of an optical path connecting the outer periphery of the lens unit with the second mirror. 2. An image reading apparatus comprising: a platen on which a document is placed; and a carriage that moves along a lower surface of the platen, wherein the carriage is configured to apply light to the document placed on the platen. An irradiation unit that irradiates light, a first mirror that reflects, in a predetermined direction, light emitted from the irradiation unit and reflected on the document surface, and a light source that reflects the light reflected from the first mirror on the document surface and the first mirror. A second mirror disposed at a position where the light is reflected across the optical path between the second mirror, a lens unit that collects light reflected from the second mirror, and a linear image sensor that photoelectrically converts image light read from the lens unit. And that both or a part of either or both of the irradiating unit and the first mirror are arranged at a position where they enter the inside of an optical path connecting the outer periphery of the lens unit from the second mirror. Image reading apparatus according to symptoms. 3. The image reading apparatus according to claim 1, wherein the irradiating unit is disposed on a side of the second mirror so as not to obstruct an optical path between the document surface and the first mirror. . 4. An effective light receiving area of the lens unit,
The image reading apparatus according to claim 1, wherein the image reading apparatus extends in the main scanning direction of the linear image sensor. 5. The image reading apparatus according to claim 4, wherein the lens unit has a plurality of lenses and an aperture member supported by a frame. 6. The iris member and / or a part of any one of the first mirror and the first mirror disposed at a position to enter the inside of an optical path connecting the outer periphery of the lens unit from the second mirror. 6. The image reading apparatus according to claim 5, wherein the image reading apparatus is disposed outside an optical path passing through the opening. 7. A shading member provided with an opening for adjusting an amount of light in a longitudinal direction of the light source is provided between the first mirror and the lens unit, and the shading member is provided from the second mirror to the lens unit. Both the irradiating unit and the first mirror and / or a part of any one of the irradiating unit and the first mirror are disposed outside the optical path passing through the opening of the shading member. The image reading device according to claim 1, wherein: 8. A shading member having an opening for correcting a light amount in a longitudinal direction of the light source is interposed between the lens unit and the linear image sensor. Both the irradiating unit and the first mirror and / or a part of any one of the irradiating unit and the first mirror are disposed outside the optical path passing through the opening of the shading member. The image reading device according to claim 1, wherein: