JP3056331B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention illuminates a transmissive original or a reflective original with illumination light from an illumination optical system unit.
The present invention relates to a flat-scanning type image reading device that reads obtained image light with a line sensor.

[0002]

2. Description of the Related Art Conventionally, an image reading apparatus that photoelectrically reads image information recorded on a document such as a film, subjects the image information to desired image processing, and creates a film original for printing and plate making has been widely used. Have been.

In an image illumination optical system of such an image reading apparatus, for example, illumination light emitted from a light source is narrowed as light linearized in a main scanning direction by a slit member or the like, and then irradiated onto a read original. Then, the light transmitted through the read original is condensed through a condensing lens and guided to a line sensor. The line sensor obtains two-dimensional image information by reading image information obtained from a read original conveyed in the sub-scanning direction in the main scanning direction.

[0004]

However, dust may enter the image illumination optical system due to convection of air due to heat generated by the light source or a cooling fan in the image reading apparatus. The dust adheres to, for example, a condenser lens, a slit member, or the like, and as a result, there is a disadvantage that a streak-like unevenness occurs in a sub-scanning direction of an output image obtained.

SUMMARY OF THE INVENTION The present invention has been made in order to overcome the above-mentioned disadvantages, and employs a Koehler illumination optical system having no illumination unevenness as means for linearizing light emitted from a light source, and excluding a Koehler illumination optical system. An object of the present invention is to provide an image reading apparatus which can prevent dust from entering the Koehler illumination optical system unit by surrounding the entire illumination optical system unit with a housing and can obtain suitable image information. .

[0006]

In order to achieve the above object, the present invention relates to an image reading apparatus which obtains image information by reading transmitted light or reflected light from a read original with a line sensor, wherein the light source and the light source are provided. A first condenser lens for condensing the reading light from the first condenser lens, a second condenser lens for guiding the reading light from the first condenser lens to the read document, and the first condenser lens and the second condenser lens. And an illumination optical system unit including a field stop for forming an image of a linearized light source on the read document, and the illumination optical system unit excluding the light source. a housing, said
The illumination optical system provided in the housing and excluding the light source
Sealing the unit allows powder to enter the housing.
And sealing means for preventing intrusion of dust .

Furthermore, the field stop has a shape of a plurality of different slits, disposed within said housing, one end of the movable rod which penetrates the Ha <br/> Ujingu is connected to the aperture the field The other end of the movable rod protruding from the housing is connected to a driving mechanism, and the slit position with respect to the optical axis is variably configured under the operation of the driving mechanism.

[0008]

According to the present invention, sealing means is provided on the housing.
Sealing the illumination optical system unit except the light source
It is possible to prevent dust from entering the housing.
Wear. Therefore, the first light source provided in the illumination optical system unit
In addition, it is possible to prevent dust from adhering to the second condenser lens, the field stop, and the like. Further, the field stop is disposed in the housing, be displaced under the action of the movable rod drive mechanism extending through the housing is connected to the diaphragm the visual field, suitably to prevent dust intrusion by said sealing means be able to.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of an image reading apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a reading unit in the image reading apparatus, FIG. 2 is a perspective view of a Koehler illumination optical system unit in the reading unit, FIG. 3 is a longitudinal sectional view of the Koehler illumination optical system unit in FIG. FIG. 3 is a perspective view of a field stop provided in the Koehler illumination optical system unit of FIG. 2 and a field stop drive mechanism for moving the field stop.

As shown in FIG. 1, the reading section 10 of the image reading apparatus comprises a Koehler illumination optical system unit (hereinafter simply referred to as an illumination optical system) 12 and a field stop driving mechanism 14. The illumination optical system 12 includes a substrate 18 on a base plate 16.
It is arranged through. The board 18 fixed on the plane of the base plate 16 by screws 19 inserted into the elongated holes 17 is provided with a pair of position adjusting members (described later) provided in contact with the side wall portions of the board 18. It is configured to be able to swing in the direction of arrow A via the same (see FIG. 3).

The illumination optical system 12 is provided in a casing 20 erected on the substrate 18. The casing 20 encloses the light source 22 and screws 24a, 24b
Light Source Holder 26 Removably Formed Via
A lens cover 32 disposed below the light source 22 and having an opening 30 for introducing reading light emitted from the light source 22 into the cylindrical lenses 28a and 28b;
A first housing 34 to which the lens cover 32 is joined on the upper surface and covers the cylindrical lenses 28a and 28b
A second housing 38 joined to the lower portion of the first housing 34 and covering the field stop 36; and a second housing 38 joined to the lower portion of the second housing 38 and covering the filter 40 and the cylindrical lenses 42a and 42b. And three housings 44. The third housing 44
The base portion 46 is fixed to the substrate 18 by screws 47 inserted through the long holes 45, and the third housing 44
The pin 49 fixed to the substrate 18 is inserted into the hole defined in the above. Therefore, the casing 20 can be rotatably displaced in the arrow B direction along the elongated hole 45 by the pair of position adjusting members 48a and 48b provided in contact with the side portions of the base portion 46. Here, the lens cover 3
The second and first to third housings 34, 38, 44 constitute a housing surrounding the illumination optical system 12.

As shown in FIG. 3, an illumination optical system 12 provided inside the casing 20 includes a light source 22 provided at an upper end of the casing 20 and a pair of light sources 22 provided below the light source 22. Cylindrical lenses 28a, 28b
A field stop 36 disposed below the cylindrical lenses 28a and 28b, a filter 40 disposed below the field stop 36 and disposed at a predetermined angle with respect to the surface of the read document, A pair of cylindrical lenses 42a and 42b are provided below the filter 40. The illumination optical system 12 forms an image of the light source 22 at the front focal point of the cylindrical lenses 42a and 42b, and reads a document to be read on an image plane formed by the cylindrical lenses 42a and 42b of the field stop 36 close to the cylindrical lenses 28a and 28b. 50 are arranged. In this case, the light source 2
The images formed by the two cylindrical lenses 42a and 42b are
Since it can be set at infinity, there is an effect that illumination unevenness does not occur. Further, the cylindrical lenses 28a and 28b
By placing the field stop 36 on a surface close to the above, there is an advantage that the outline of the field stop 36 becomes clear.

Openings 51 and 52 for transmitting light are formed on the bottom surfaces of the first housing 34 for holding the cylindrical lenses 28a and 28b and the third housing 44 for holding the cylindrical lenses 42a and 42b. Have been. A document cassette 58 having a read document 50 sandwiched between a cover glass 54 and a support glass 56 is disposed in a substantially vertical direction of the opening 52, and a light collector that collects light transmitted through the read document 50. A lens 60 and a line sensor (for example, a CCD) 62 having a light receiving surface for receiving the transmitted light and converting the received light into an electric signal are provided.

The inner walls of the first housing 34 and the third housing 44 and the cylindrical lenses 28a, 28
b, 42a, and 42b, respectively.
4a, 64b are provided, and the coil springs 64a,
Each cylindrical lens 2 with the resilience of 64b
8a, 28b, 42a, 42b are fixed at predetermined positions. The coil springs 64a and 64b may be leaf springs.

Here, the position adjusting members 48a and 48b for displacing the substrate 18 or the casing 20 so as to swing freely will be described. As shown in FIGS. 2 and 3, the position adjusting members 48a and 48b have substantially cylindrical rollers 66a,
Eccentric pins 68a and 68b are provided integrally with 66b,
The lower ends of the eccentric pins 68a and 68b are inserted into holes of the base plate 16 or the substrate 18 so as to sandwich both ends of the substrate 18 and the casing 20. The eccentric pin 6
Minus grooves are cut in the upper end portions of the substrates 8a and 68b, and by rotating the rollers 66a and 66b through the grooves, the substrate 18 is moved along the long holes 17 by arrows A.
Displace in the direction. Further, the casing 20 can be rotationally displaced in the arrow B direction along the elongated hole 45 with the pin 49 as a fulcrum. The position adjusting members 48a, 48
The lower end of the position adjusting member 4b may be always fitted into the hole of the base plate 16 or the substrate 18, but only at the time of adjustment.
Position adjustment may be performed by fitting the lower ends of 8a and 48b into the holes.

Another embodiment of the position adjusting members 48a, 48b is shown in FIGS. The position adjusting member 53 shown in FIG.
Are a plurality of recesses 55a defined at one end of the substrate 18.
And a plurality of recesses 55 b provided on the inner wall surface of the groove 61 defined near one end of the base plate 16. Therefore, for example, the position of the base plate 16 and the substrate 18 can be adjusted by inserting a minus driver into the opposed concave portions 55a and 55b and twisting the driver. The distance L1 between the recesses 55a and the distance L2 between the recesses 55b have a relationship of L1 ≠ L2.
The position between the base plate 16 and the substrate 18 can be easily adjusted. Also, instead of the position adjusting members 48a and 48b, a plurality of recesses 55a and 55b are defined in the side wall of the third housing 44 and the substrate 18, respectively, and the pins 49 are pivoted by prying with a screwdriver as described above. The position can be adjusted by rotating and displacing the casing 20 in the direction of arrow B. On the other hand, the position adjusting member 57 shown in FIG. 9 is configured by inserting an eccentric pin 63 inserted into a hole of the base plate 16 into a long hole 59 defined in the substrate 18. The eccentric pin 63 is inserted through a minus groove provided in the eccentric pin 63.
Is rotated by a driver so that the substrate 18
The position of the substrate 18 and the base plate 16 can be adjusted by swinging and displacing in the direction.

The field stop 36 is, as shown in FIG.
A slit plate 74 which is connected to a movable rod 70 having a roller 110 provided at a distal end thereof and has a plurality of slits 72a to 72c, and a pair of bearings which are fixed to the lower portion of the slit plate 74 so as to face each other. Parts 76a, 76b, two shafts 78a, 78b, both ends of which are supported by the bearings 76a, 76b and arranged substantially in parallel, are fixed to the bottom surface of the second housing 38, and slide bearings (not shown) And fixing members 80a and 80b for holding the shafts 78a and 78b via the first and second shafts. The movable rod 70 fits through a closing member 82 that is joined between the first and second housings 34 and 38, and the distal end thereof is connected to the field stop driving mechanism 14, which will be described later. The hole 84 in which the movable rod 70 and the closing member 82 are in sliding contact with each other has v
Oil seal 8 as sealing means having a U-shaped cross section
6 are provided and are kept airtight. The widths and / or lengths of the slits 72a to 72c defined in the slit plate 74 are different, and the plurality of slits 72a to 72c are urged by energizing a field stop driving mechanism 14 described later.
It is possible to select a desired slit from c.

The filter 40 is fixed inside a filter case 88, and the filter case 88 is disposed in a chamber 92 of the third housing 44 via a leaf spring member 90 having an inverted U-shaped cross section. . An intervening member 94 is provided between the filter case 88 and the second housing 38, and under a pressing action of the intervening member 94, via a leaf spring member 90, the filter case 88 and the cylindrical lens 42a,
42b is pressed substantially vertically downward to be fixed in the chamber 92 of the third housing 44. A pair of adjusting screws 96a, 9 for adjusting the position of the filter case 88 are provided on both side walls of the third housing 44 near the filter case 88.
6b is provided. That is, the third housing 44
A narrow gap is provided between the chamber 92 defined therein and the filter case 88, and a pair of adjusting screws 96 a and 96 b abutting on the side surface of the filter case 88.
To displace the filter case 88,
The position of the filter 40 in the chamber 92 can be adjusted. In this way, by adjusting the position of the filter 40, the center of the filter 40 is moved to
The optical axes of the reading light emitted to the line 0 and the line sensor 62 that receives the light transmitted through the read document can be made to coincide with each other.

The central portion 40a of the filter 40 is set so as to correspond to the numerical aperture of the condenser lens 60, and is set to be lower than the light transmittance of the surrounding portion 40b. . For this reason, for example, even if the read original 50 has a flaw or the like and the transmitted light is bent by this, the central portion 40a of the filter 40
The decrease in the amount of light can be compensated for by the reading light that has passed through the surrounding portion 40b and entered the reading original 50. As a result, the obtained image is a suitable image without noticeable scratches or the like.

The filter 40 is disposed in the filter case 88 at a predetermined angle with respect to the original 50 to be read. For this reason, light reflected on the cover glass 54 of the document cassette 58 and the surface of the read document 50 is re-reflected on the lower surface of the filter 40, and the flare that causes deterioration in image quality is prevented from being input to the line sensor 62. can do.

On the other hand, a field stop driving mechanism 14 is disposed on the base plate 16 in proximity to the illumination optical system 12 (see FIGS. 1 and 4). The field stop drive mechanism 14 includes a base plate 16
A motor bracket 98 is screwed thereon, and a pulse motor 100 that directs the motor shaft substantially vertically upward is fixed to an inner wall portion of the motor bracket 98. A pinion 102 is connected to a tip of a motor shaft of the pulse motor 100, and an idle gear 104 supported on an upper surface of a motor bracket 98 meshes with the pinion 102. A gear 106 and an eccentric cam 108 are coaxially supported on the upper surface of the motor bracket 98, and the idle gear 104 meshes with the gear 106. A roller 110 slides on the outer peripheral surface of the eccentric cam 108, and the roller 110 is connected to the movable rod 70 fixed to the slit plate 74. Further, a fan-shaped light shielding plate 112 is connected coaxially with the gear 106 and the eccentric cam 108. Therefore,
The gear 106, the eccentric cam 108 and the light shielding plate 112
Are simultaneously rotated because they are coaxially and integrally supported. A photo interrupter 114 including a light emitting unit and a light receiving unit is provided in the main body (not shown) of the image reading apparatus in proximity to the light blocking plate 112 to detect the rotation angle and the like of the eccentric cam 108. I have.

The image reading apparatus according to the present embodiment is basically configured as described above, and the operation and effect of the image reading apparatus will now be described.

First, when assembling the reading unit 10, the third
Adjustment screws 96 provided on both side walls of the housing 44
The position adjustment of the filter 40 is performed via a and 96b. Subsequently, the linearized light from the light source 22 is sent to the line sensor 6.
The eccentric pins 68a, 68b of the position adjusting members 48a, 48b abutting on both side walls of the substrate 18 are rotated in a predetermined direction in order to correctly guide the light to the second linear light receiving surface. As a result, the rollers 66a, 66b integrally connected to the eccentric pins 68a, 68b rotate, and the outer peripheral surfaces of the rollers 66a, 66b abutting against the side wall of the substrate 18 press the side wall, and the substrate 18 is pressed. By swinging and displacing in the direction of arrow A along the long hole 17, the substrate can be fixed at a desired position to perform position adjustment. Similarly, via the position adjusting members 48a and 48b which contact the casing 20 of the illumination optical system 12,
The casing 20 of the illumination optical system 12 is rotationally displaced in the direction of arrow B about the pin 49 along the elongated hole 45, and the light transmitted through the read original 50 is aligned with the light receiving surface of the line sensor 62. In this case, with the slit 72a defined in the field stop 36 set on the optical axis, the line sensor 6
Positioning is performed by displacing the illumination optical system 12 to a position where the output value of 2 becomes maximum. The position adjusting member 48a,
As a matter of course, the positions of the substrate 18 and the casing 20 may be adjusted by using the position adjusting members 53 and 57 shown in FIG. 8 or 9 instead of 48b.

As described above, the position adjusting members 48a, 48
After the positions of the substrate 18 and the casing 20 of the illumination optical system 12 are adjusted via 8b, the substrate 18 and the casing 20 of the illumination optical system 12 are fixed with screws 19 and 47. As a result, the light linearized by the illumination optical system 12 is set to coincide with the linear light receiving surface of the line sensor 62. Thereafter, the eccentric cam 108 of the field stop drive mechanism 14
Then, the roller 110 is brought into contact with the predetermined position, and the motor bracket 98 is fixed.

A case where the image reading apparatus thus assembled reads the image information from the read document 50 on which the image information is recorded will be described with reference to the flowchart shown in FIG. First, at the time of initial setting, the pulse motor 100 of the field stop driving mechanism 14 is driven by turning on the power of the image reading apparatus (step S1). The rotation of the pulse motor 100 causes the pinion 10 to rotate.
The eccentric cam 108 rotates via the idle gear 104 meshing with the gear 2 and the gear 106 meshing with the idle gear 104 (step S2). The light shielding plate 112 coaxially connected to the eccentric cam 108 rotates together with the eccentric cam 108. The light blocking plate 112 is rotated to rotate the photo interrupter 11 fixed to the main body of the image reading apparatus.
4 passes between the light emitting unit and the light receiving unit. Therefore, the position of the light-shielding plate 112 can be confirmed from the time when the light from the light-emitting unit is blocked by the light-shielding plate 112 and does not reach the light-receiving unit (step S3). After confirming the position of the light shielding plate 112,
If the eccentric cam 108 is rotated by a preset angle, the eccentric cam 108 will be set to the home position (step S4).

Next, for example, by changing the optical magnification of the image, the slits 72b formed in the field stop 36,
The slit adjustment mode (step S5) for adjusting the position of 72c will be described with reference to the subroutine flowchart shown in FIG.

First, a desired optical magnification is set by moving the condenser lens 60 and the line sensor 62 (step S).
5a, step S5b). The setting of the optical magnification is performed by moving the condenser lens 60 and the line sensor 62 along a direction of the optical axis via moving means (not shown). Next, for the field stop 36, a slit 72b or a slit 72c having a slit width and length corresponding to the optical magnification is selected (step S5c).

That is, the driving of the pulse motor 100 causes the pinion 102 supported by the pulse motor 100 to rotate.
Rotate, the idle gear 104 meshing with the pinion 102 rotates based on the rotation of the pinion 102, and the gear 106 meshing with the idle gear 104 rotates. The eccentric cam 10 integrally connected to the gear 106
8 rotates. This eccentric cam 108 is
Slidably contacts the roller 110 connected to the eccentric cam 108.
The movable rod 70 is displaced in the direction of arrow A by the rotation of.
Therefore, with the displacement of the movable rod 70, the slit plate 74 connected to the movable rod 70 is displaced in the direction of arrow A. As a result, a slit 72b or a slit 72c defined in the slit plate 74 and having a width and / or a length corresponding to the optical magnification can be set.

Here, for example, when a desired slit 72b of the field stop 36 is set on the optical axis,
b when the axis of the light transmitted through b is slightly shifted from the optical axis, and the band of light obtained by condensing the image light transmitted through the reading original 50 is displaced from the linear light receiving surface of the line sensor 62. There is.

Then, after setting the slit 72b, the amount of light incident on the light receiving surface of the line sensor 62 is measured (step S5d). Next, the field stop drive mechanism 14 is operated,
The field stop 36 is moved in the direction of arrow A (step S5).
e). The movement of the field stop 36 and the measurement of the amount of light are performed by driving the pulse motor 100 by deriving a signal from a control circuit (not shown) to the pulse motor 100, and moving the movable rod 70 slidably in contact with the eccentric cam 108 via the roller 110 by step feed. It is done by doing.

In this way, the step feed of the movable rod 70 is repeated a specified number of times (step S5f).
The field stop 36 is displaced in the direction of arrow A. Next, a light amount distribution is obtained from the output signal level of the line sensor 62, and a maximum light amount position of light incident on the light receiving surface of the line sensor 62 is obtained from the light amount distribution. Next, the pulse motor 1
The signal is derived at 00 and the field stop 36 is moved to the maximum position of the light quantity (step S5g).

Next, before irradiating the reading original 50 with reading light and performing image processing, the same kind of glass having a thickness equivalent to the thickness of the glass plate of the cover glass 54 and the supporting glass 56 of the original cassette 58 in advance. A shading correction is performed to irradiate the plate with reading light to obtain correction data for reading the read original 50 (step S6). Based on the obtained correction data, it is possible to make an electrical correction when reading the image information.

The illumination optical system 12 except for the light source 22 in the reading section 10 is connected to, for example, a cover member including the lens cover 32 and the first to third housings 34, 38 and 44, and a slit plate 74. By providing an oil seal 86 having a substantially V-shaped cross section at a position where the movable rod 70 and the closing member 82 are in sliding contact with each other, the interior of the illumination optical system 12 can be kept airtight. For this reason,
A cylindrical lens 28a in the illumination optical system 12,
It is possible to prevent dust from adhering to 28b, 42a, 42b, the field stop 36, and the like. In the slit adjustment mode, even if the field stop 36 is displaced by changing the optical magnification of the image to change the slit width or the like, the first to third housings 34, 3
Since the insides of the sections 8 and 44 are kept airtight, the intrusion of dust can be suitably prevented. As a result, step S6
, Accurate shading correction can be performed.

Subsequently, a so-called pre-scan is performed to obtain image information for setting processing conditions when reading the image information (step S7). That is, the light source 2
The reading light emitted from 2 passes through the reading original 50 held in the original cassette 58 and is introduced into the line sensor 62 via the condenser lens 60. The line sensor 62 converts the light transmitted through the read original 50 into an electric signal.
The electric signal is subjected to predetermined processing in a circuit of a control device (not shown), and then stored as a prescan image and displayed on a display unit (not shown) of the image reading device. Therefore, the operator sets (sets up) processing conditions based on the pre-scanned image displayed on the display unit of the image reading device.

The image reading apparatus which has completed the pre-scanning and the setup is scanned (main scanning) by the reading unit 10 based on the processing conditions, and outputs output image information (main scanning image) for reproduction (step). S
8).

By repeating the above steps S5 to S8 (step S9), a plurality of desired output image information can be obtained. The output image information is
After being supplied to an image output device (not shown) and converted into an optical signal such as a laser beam, a clear image without stripes and unevenness is reproduced on the film. This film is transferred to an automatic developing device and subjected to a developing process, whereby a desired film original can be obtained.

Next, a reading section of an image reading apparatus according to another embodiment of the present invention is shown in FIG. Note that the same reference numerals are given to components corresponding to the above-described embodiment, and detailed description thereof will be omitted.

In the above-described embodiment, the movable rod 70 is connected to the field stop 36, and the movable rod 70 is formed so as to protrude from the closing member 82 via the oil seal 86. Field stop 36 in system 122
Is closed, and the field stop 36 and the movable rod 126 connected to the field stop drive mechanism 124 are separated from each other.
The field stop 36 is moved by the magnetic force of the magnet 128 fixed to the tip of the field stop 26 and the magnet 130 fixed to one end of the field stop 36. In this embodiment, the number of components can be reduced without the need for an oil seal, and the airtightness in the housings 132 and 134 surrounding the illumination optical system 122 can be improved.

[0040]

According to the image reading apparatus of the present invention, the following effects can be obtained.

[0041] That is, by sealing the housing the illumination optical system unit of the sealing means is provided, except for the light source, dust due to heat generation of the light source generated by the cooling fan or the like convection or image reading in the apparatus of air, the lighting It can be prevented from adhering to the first and second condenser lenses, the field stop, and the like provided in the optical system unit. Further, the field stop is arranged in front Symbol housing, because the site where the movable rod and the housing that is connected to the aperture the field is in sliding contact sheet Lumpur means are provided, wherein the field stop is a movable rod Even if it is displaced through, the intrusion of dust can be reliably prevented by the sealing means . As a result, it is possible to obtain a suitable output image without streak-like unevenness.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reading unit of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a Koehler illumination optical system unit of the reading unit shown in FIG.

FIG. 3 is a longitudinal sectional view of the Koehler illumination optical system unit shown in FIG. 2;

FIG. 4 is a perspective view of a field stop and a field stop driving mechanism for displacing the field stop.

FIG. 5 is a flowchart illustrating an operation of the image reading apparatus illustrated in FIG. 1;

FIG. 6 is a subroutine flowchart showing an operation in a slit adjustment mode in FIG. 5;

FIG. 7 is a sectional view of a reading unit of an image reading apparatus according to another embodiment of the present invention.

FIG. 8 is an explanatory view showing another embodiment of the position adjusting member.

FIG. 9 is an explanatory view showing another embodiment of the position adjusting member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Reading part 12 ... Koehler illumination optical system unit 14 ... Field stop drive mechanism 16 ... Base plate 18 ... Substrate 20 ... Casing 22 ... Light source 26 ... Light source holder 28a, 28b, 42a, 42b ... Cylindrical lens 32 ... Lens cover 34 , 38, 44 ... housing 70 ... movable rod 82 ... closing member 86 ... oil seal

Claims (2)

(57) [Claims] An image reading apparatus for reading transmitted light or reflected light from a read document by a line sensor to obtain image information, comprising: a light source; a first condenser lens for condensing the read light from the light source; A second condenser lens that guides the reading light from the first condenser lens to the read document, and a second condenser lens that is provided between the first condenser lens and the second condenser lens. a housing enclosing an illumination optical system unit including a field stop to form an image of the linearized light source, the illumination optical unit excluding the light source, provided in the housing, the illumination light except the light source
By sealing the academic unit,
An image reading device comprising: a sealing unit for preventing intrusion of dust . 2. The field stop according to claim 1, wherein the field stop has a plurality of slits having different shapes , and is disposed in the housing , and one end of a movable rod passing through the housing is connected to the field stop. Linked, the how
An image reading apparatus, wherein the other end of a movable rod protruding from a jing is connected to a driving mechanism, and the slit position with respect to the optical axis is variably configured under the operation of the driving mechanism.