JP3317039B2 - Image reading device - Google Patents

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 used in a copying machine, a facsimile, an image scanner, etc., for exposing and scanning a document surface to convert reflected light into an image signal.

[0002]

2. Description of the Related Art Conventionally, there has been known an image reading apparatus for exposing and scanning a document surface to convert it into an electric image signal. For example, as shown in FIG. There is a type in which an electric image signal is obtained by arranging a photoelectric conversion element (image sensor) at an image forming position through a lens through the lens. In this image reading apparatus, the original 110
And a lamp 102 for exposing and scanning the original surface from below the platen glass 101.
And a mirror 103 for guiding light reflected on the original surface to a lens;
An image light detection unit 104 having a lens 105 and an image sensor 106 is provided. The above lens 105
Is fixed to a substantially cylindrical support, and this support is fixed and supported by a base 107 such as a frame. The position is adjusted and fixed so that an image is accurately formed on an image sensor, and It must be firmly fixed so that the position does not move due to the vibration at the time.

As a means for fixing such a substantially cylindrical support, there is, for example, a technique disclosed in Japanese Utility Model Laid-Open Publication No. 3-46275. A lens mounting device described in Japanese Utility Model Laid-Open Publication No. 3-46275 has a lens support plate provided with a lens hole into which a lens support is fitted, and a lens holding plate fixed to the lens support plate so as to surround the lens support. The lens is fixed by abutting a tip of a screw screwed on the lens pressing plate against a lens support, and pressing the support against the lens support plate.

[0004]

However, in the prior art as described above, the position of the lens is finely adjusted in order to form a clear image at the position of the image sensor, and the lens is firmly fixed at the adjusted position. There is a problem that it is difficult to do. In addition, there is a problem in that the detected image signal is disturbed due to the influence of flare light that enters the image sensor through the outside of the lens support without passing through the lens. Hereinafter, this problem will be described in detail.

[0005] As shown in FIG.
A shielding plate 108 is provided in front of the image sensor 10 in order to prevent flare light. Light passing through a gap between the lens support 109 and the shielding plate 108 (indicated by reference numeral C in the drawing) is reflected by the image sensor 10.
6 is incident. Such flare light is generated by the image sensor 1
When the light enters at 06, signals (voltages) from the image sensor should be output with a distribution as shown in FIG. 13A for an original having uniform brightness in the scanning direction.
The output due to the flare light as shown in FIG. 3B is mixed, and an image signal corresponding to the image of the document cannot be obtained.

On the other hand, as shown in FIG.
By providing a shielding plate 108 close to the end surface of the lens support 109 on the image sensor 106 side and covering just outside the effective optical path D of the image light, the incidence of flare light can be prevented. However, in the conventional apparatus including the apparatus described in Japanese Utility Model Laid-Open No. 3-46275, the shielding plate 108 is fixed and supported by a frame or the like serving as a base, and when the position of the lens is adjusted, the relative position to the lens is reduced. The position changes, and as shown in FIG. 14B, the effective optical path D of the image light is blocked,
The flare light may be incident on the image sensor. On the other hand, it is conceivable that the shielding plate is a member continuously projecting from the lens support, but there is a problem that processing cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to accurately adjust the position of a lens so that the lens can be firmly fixed and to prevent flare light that does not pass through the lens. An object of the present invention is to provide an image reading device capable of preventing input to an image sensor.

[0008]

According to a first aspect of the present invention, there is provided an image processing apparatus for detecting reflected light caused by exposing and scanning an original surface and converting the reflected light into a digital image signal. An image reading device, comprising: a lens that converges and forms an image of the reflected light; and a plurality of photoelectric conversion elements that are arranged at an image forming position of the reflected light and convert incident light into an image signal for each pixel. In the reading device,
A cylindrical lens support that supports the periphery of the lens, and a plate-like member that is disposed substantially parallel to the axis of the lens.
A first support plate for supporting the lens support by restricting movement in a direction perpendicular to the axial direction of the lens support; and one end face of the lens support provided on the first support plate. A first locking portion that abuts the lens support and restricts movement of the lens support in one of the axial directions; and a first support plate that overlaps with the first support plate , A second support plate that is fixedly supported by adjusting its position in the axial direction; and a second support plate that is provided on the second support plate and abuts on the other end surface of the lens support in the axial direction of the lens support. A second locking portion for restricting the movement to the other, and in the vicinity of the end face of the lens support on the photoelectric conversion element side,
And a shielding portion that stands upright from the first support plate or the second support plate and protrudes outside the effective optical path of the lens.

According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, the shielding portion includes a first shielding plate erected from the first support plate and the second shielding plate. It is assumed that it is composed of a second shielding plate erected from the support plate.

According to a third aspect of the present invention, in the image reading device according to the first or second aspect, the photoelectric conversion element is provided in the first locking portion or the second locking portion. The locking portion on the side constitutes a part of the shielding portion.

In the first aspect, the photoelectric conversion element is
Various types of light, such as those that detect a specific color of light, or those that detect only the brightness of black and white can be used, and a large number of elements are arranged in one or more rows. Can be The first support plate and the second support plate are used in an overlapping manner, and both can be adjusted in position and fixed to a frame or the like of a device serving as a base. The relative position between the plate and the second support plate can also be adjusted and fixed.
Either of the first support plate and the second support plate may be on the upper side, and if the above-described configuration is provided, the shape and dimensions can be arbitrarily designed.

In addition, the first locking portion and the second locking portion can be arbitrarily determined in their shapes and the like as long as they can restrict the movement of the lens support in the axial direction. It may be a protrusion or an edge of an opening provided in the support plate. Further, the shielding part may be a single one, but it is desirable to combine a plurality of plate-like members, and the shape and the like appropriately shield the periphery of the effective optical path to prevent the incidence of flare light. Anything that can be prevented can be used. In the above configuration, the axial direction of the lens support refers to the axial direction of light transmitted through the lens.

[0013]

According to the image reading apparatus of the first aspect, the first
The second support plate and the second support plate are arranged so as to overlap with each other, and the relative position of the lens support in the axial direction can be adjusted. The movement of the lens support in the axial direction can be restrained and fixed by the locking portion. Further, the lens support is restricted from moving in a direction perpendicular to the axis by the first support plate. Further, the first support plate and the second support plate restrain the lens support as described above and are fixedly supported by adjusting the position in the axial direction of the lens, so that the lens is firmly supported and It can be fixed at an accurate position with respect to the conversion element. Further, since the first or second support plate and the lens support can be integrally formed and the position with respect to the photoelectric conversion element can be adjusted without changing the relative position, the shielding portion provided on the support plate can be used. The relative position with the lens does not change. Therefore, there is no gap between the shielding portion and the lens support for the flare light to enter, and the shielding portion does not block the effective optical path.

[0014] In the image reading apparatus according to the second aspect,
The shielding portion is composed of a portion divided into two or more, and is configured by a first shielding plate erected from the first support plate and a second shielding plate erected from the second support plate. Therefore, even if the size of each shielding plate is reduced, the incidence of flare light can be effectively prevented, the first support plate and the second support plate are overlapped, and their relative positions are easily adjusted. Is adjusted to obtain a structure capable of restraining the lens support.

[0015] In the image reading apparatus according to the third aspect,
Since the locking portion that comes into contact with the end surface of the lens support on the side where the photoelectric conversion element is located forms a part of the shielding portion, this shielding portion is always in close contact with the lens support, and effectively generates flare light. Incident can be prevented. Further, the structure for fixing the lens support can be simplified.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of an image light detecting unit used in the image reading apparatus, and FIG. 3 is a sectional view of the same image light detecting unit. The image reading apparatus includes a platen glass 1 on which a document 9 is placed, an exposure lamp 2 for irradiating a document surface from below the platen glass 1, and first and second light paths for forming light paths of reflected light from the document surface. , The third mirror 3,
4 and 5, a lamp carriage 6 carrying the exposure lamp 2 and the first mirror 3 and traveling in the sub-scanning direction.
A mirror carriage 7 having a second mirror 4 and a third mirror 5 mounted thereon and traveling at a half speed in the same direction as the lamp carriage, and a first mirror, a second mirror and a third mirror from the document surface. And an image light detection unit 8 that converts the reflected light guided into an electric image signal. Hereinafter, the image light detecting unit, which is a feature of the present invention, will be described in detail.

The image light detecting unit 8 has a housing 11 for preventing extra light from being incident thereon. A lens unit 12 and an image sensor 14 mounted on an upright substrate 13 are provided inside the housing 11. Provided. The lens unit 12 includes a lens that forms an image of the reflected light from the document at the position of the photoelectric conversion element, and a substantially cylindrical lens support 15 that supports the lens.
5 is fixed to the base 18 via the first support plate 16 and the second support plate 17.

As shown in FIG. 4, the first support plate 16 has a stepped portion 16a whose central portion is bent slightly upward from the peripheral portion. Long opening 16b narrower than outer diameter of lens support
Is provided. The lens support 15 is provided in the opening 16b.
Is fitted, and the lens support 15 is fixed to the first support plate 16 by fastening with a metal belt 19. At this time, since the width of the opening 16 b is smaller than the outer diameter of the lens support 15, the outer peripheral surface has the edge 1 facing the opening.
6c, 16d and firmly fixed so as not to move in the direction perpendicular to the axis. On the other hand, the mirror-side end surface of the lens support is in contact with the mirror-side edge 16e of the opening 16b, and serves as a first locking portion that restricts movement toward the mirror. On the image sensor side of the first support plate 16,
Shielding plates 20 are provided substantially vertically on both sides of the optical path. In FIG. 4, reference numeral 16f denotes a locking hole of the metal belt, reference numeral 16g denotes a through hole for fixing the first support plate to the second support plate, and reference numeral 16h denotes a position of the first support plate. A guide hole, reference numeral 16i is an adjustment hole for adjusting the position of the first support plate in the optical axis direction, and a reference numeral 16j is a projection with which the metal belt is brought into contact. The functions of the adjustment hole and the guide hole will be described later.

As shown in FIG. 2, the second support plate 17 has a width slightly larger than the first support plate 16 in a direction perpendicular to the axis of the image light. 5, and has a shielding plate 17a standing upright from the vicinity of the edge on the image sensor 14 side as shown in FIG. The shielding plate 17a has a frame shape extending around the opening 17b through which the image light passes, and its outer edge is bent in the axial direction of the image light to effectively block flare light with a small size. Also, this shielding plate 17
“a” functions as a second locking portion, and the end surface of the lens support 15 on the image sensor side is abutted to restrict the movement to the image sensor side. FIG.
Reference numeral 17c in the figure is a screw hole for fixing the second support plate to the base, and is a long hole so that the position can be adjusted in the axial direction of the lens support 15, that is, in the axial direction of the image light. I have. Reference numeral 17d denotes a screw hole for fixing the first support plate 16 to the second support plate 17, and reference numeral 17d denotes a screw hole.
e is an opening for providing a gap for locking the metal belt 19 to the first support plate 16, and 17f is a position adjusting bolt 2
Reference numerals 17g and 17h denote holes through which 1 passes and holes and cutouts through which positioning studs pass. The position adjustment bolt and the positioning stud will be described later.

As shown in FIG. 6, the first support plate 16 and the second support plate 17 are mounted on the base 18 as shown in FIG. The lens support 15 is fixed on the first support plate 16. When the first support plate 16 and the second support plate 17 are overlapped, the shielding plate 17a erected from the second support plate 17 penetrates the opening 16b of the first support plate 16 to adjust the angle. And overlap. As a result, as shown in FIG. 6, the shielding plate 17a erected from the second support plate 17 is located on the image sensor side of the opening 16b, and is supported by the edges 16c and 16d on both sides of the opening. It comes into contact with the end face of the body 15 on the image sensor side. Further, two shield plates 2 erected from the first support plate 16 are provided.
In combination with 0 and 20, it becomes a form that can effectively block flare light.

The lens support 15 supported on the first support plate 16 is sandwiched between a mirror-side edge 16e of the opening 16b and a shielding plate 17a provided upright from the second support plate 17, and extends in the axial direction. As shown in FIG. 2, the metal belt 1 is fixed so as not to move, and has one end locked to the opening 16f.
9 is fastened and fixed to the first support plate 16 and the second support plate 17 by bolts 22. In addition, the bolt 22 fixes the first support plate 16 and the second support plate 17 together with the bolt 23.

As described above, the lens support 15, the first support plate 16 and the second support plate 17 are fixed so as to be integral with each other, and the positioning studs 24, 24 protruding from the base are provided. Guide holes 16h, 16 of first support plate 16
h. These guide holes 16h, 16h
Is a long hole in the axial direction of the image light, and the movement in the direction perpendicular to the axis of the image light and in the turning direction is restricted by the two positioning studs 24, 24, but the position in the axial direction of the image light is restricted. Can be adjusted. The head of a position adjustment bolt 21 screwed into a screw hole provided in the base is inserted through the adjustment hole 16i. The position adjusting bolt 21 is a bolt whose head is eccentric as shown in FIG. 2 or FIG. 6, and rotates the first supporting plate 16, the second supporting plate 17, and the lens support 15 to form an image. It can be moved in the axial direction of the light and adjusted to an accurate position.

Further, the second support plate 17 is fixed to the base with the position adjusted as described above, and a screw hole is provided in the base 18 so as to correspond to the through holes 17c, 17c. The second support plate 17 and the first support plate fixed thereto are fixed by bolts inserted into the through holes.
Support plate 16 and lens support plate 15 can be fixed.

On the other hand, as shown in FIGS. 2 and 3, the image sensor 14 of the image light detecting unit
The substrate 13 is mounted on the substrate support plate 3.
0, vertical position adjustment plate 31, rotation adjustment plate 32
Are supported by the base 18. The substrate support plate 30 has a shape as shown in FIG.
7A is a plan view, and FIG. 7B is a front view. As shown in FIGS. 2 and 3, the substrate support plate 30 supports the substrate 13 with bolts 33 and springs 34 mounted around the bolts. The position can be adjusted in the axial direction of the image light. In FIG. 7, reference numeral 30a denotes an opening through which image light passes.

The vertical position adjusting plate 31 has a shape as shown in FIG. 8, wherein FIG. 8 (a) is a plan view and FIG. 8 (b) is a front view. This vertical position adjustment plate 3
1 is fixed to the substrate support plate 30 and
It is supported by a rotation adjusting plate by a bolt 35 and a spring 36 which are arranged in a substantially vertical direction. By adjusting the rotation of the bolt 35, the vertical position adjusting plate can be moved in the vertical direction to perform fine position adjustment. I can do it. The rotation adjusting plate 32 has a shape as shown in FIG. 9, and FIG.
FIG. 9B is a front view. This rotation adjustment plate 32
The opening 32a is locked to a rotating shaft provided on the base,
By turning around this rotation axis, the position in the rotation direction can be adjusted. In addition, the U-shaped notch 32b has
As shown in (1), the head of the screw 37 whose head is eccentric is locked, and by rotating this screw 37, a minute rotation angle can be adjusted.

As described above, the position and angle of the image sensor 14 are adjusted by the substrate support plate 30, the vertical position adjustment plate 31, and the rotation adjustment plate 32, and the first support plate 16 for supporting the lens and the second support plate. By adjusting the position of the support plate 16, the image light reflected on the document surface is guided to the lens via the mirror, and the image sensor 14
It can be focused on and converted into an electrical image signal. At this time, in addition to the image light, extra flare light enters the housing 11 from the opening 11a provided in the housing 11 of the image light detection unit 8, but as shown in FIG. 17a, 20 block. Also,
As shown in FIG. 3B, the light B reflected by the top plate of the housing is also blocked by the shielding plates 17a and 20 and the image sensor 1
4, and an image signal without disturbance can be obtained.

[0027]

As described above, in the image reading apparatus according to the first aspect, the lens support having a built-in lens is connected to two superposed support plates and the first locking portion provided on these two support plates. The second locking portion allows the image light to be restrained so as not to move in the axial direction and the direction perpendicular thereto, and to be firmly fixed. Further, since the two support plates to which the lens supports are fixed can be adjusted in position and fixed, the lens can be fixed in an appropriate position. Further, the shielding portion is provided on the support plate and provided so as to be in close contact with the lens support, and the relative position between the lens support and the shielding portion does not change even if the position of the lens support is moved and adjusted. In addition, it is possible to reliably prevent the flare light from being incident on the image sensor.

Further, in the image reading apparatus according to the second aspect, the shielding portion is composed of two or more divided portions,
And a second shielding plate erected from the second supporting plate, and a first shielding plate erected from the supporting plate of
Even if the size of each shielding plate is reduced, the incidence of flare light can be effectively prevented, the first support plate and the second support plate are overlapped, and their relative positions are easily adjusted. Thus, a structure capable of restraining the lens support can be obtained.

In the image reading device according to the third aspect,
Since the locking portion that comes into contact with the end surface of the lens support on the side where the photoelectric conversion element is located forms a part of the shielding portion, this shielding portion is always in close contact with the lens support, and effectively generates flare light. Incident can be prevented. Further, the structure for fixing the lens support can be simplified.

[Brief description of the drawings]

FIG. 1 is an overall sectional view schematically showing an image reading apparatus according to an embodiment of the invention described in claim 1, 2 or 3.

FIG. 2 is a plan view showing a main part of the image reading apparatus shown in FIG.

FIG. 3 is a vertical sectional view showing a main part of the image reading apparatus shown in FIG.

FIG. 4 is a plan view and a front view showing a first support plate used in the image reading apparatus of FIG. 1;

FIG. 5 is a plan view and a front view showing a second support plate used in the image reading apparatus of FIG. 1;

6 is a plan view, a front view, and a cross-sectional view showing a state where the first support plate shown in FIG. 4 and the second support plate shown in FIG. 5 are superimposed.

FIGS. 7A and 7B are a plan view and a front view showing a substrate support plate used in the image reading apparatus of FIG. 1;

8A and 8B are a plan view and a front view showing a vertical position adjustment plate used in the image reading device of FIG.

9A and 9B are a plan view and a front view showing a rotation adjustment plate used in the image reading device of FIG.

FIG. 10 is an explanatory diagram illustrating a flare light blocking effect of an image detection unit used in the image reading device of FIG. 1;

FIG. 11 is a schematic configuration diagram illustrating an example of a conventional image reading apparatus.

FIG. 12 is a diagram showing a state of incidence of flare light in a conventional image reading apparatus.

FIG. 13 is a diagram illustrating an example of an output when flare light is incident on an image sensor in a conventional image reading apparatus.

FIG. 14 is a diagram illustrating one of problems in a conventional image reading apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Platen glass 2 Exposure lamp 3 Mirror 4 Mirror 5 Mirror 6 Lamp carriage 7 Mirror carriage 8 Image detection unit 11 Housing of image detection unit 12 Lens unit 13 Substrate 14 Image sensor 15 Lens support 16 First support plate 17 Second Support plate 18 Base 19 Metal belt 20 Shielding plate 21 Position adjustment screw 30 Substrate support plate 31 Vertical position adjustment plate 32 Rotation adjustment plate

Claims (3)

(57) [Claims] 1. An image reading apparatus for detecting reflected light resulting from exposure scanning of a document surface and converting the reflected light into a digital image signal, comprising: a lens for converging and forming the reflected light; An image reading device that is arranged at an image forming position and has a plurality of photoelectric conversion elements that convert incident light into an image signal for each pixel; and a cylindrical lens support that supports the periphery of the lens; A plate-like member that is placed almost parallel to the axis
A first support plate for supporting the lens support by restraining movement in a direction perpendicular to the axial direction thereof; and a first support plate provided on the first support plate and contacting one end face of the lens support. A first locking portion that is in contact with and restricts movement of the lens support in one direction in the axial direction; and a first support plate that overlaps with the first support plate, and
A second support plate that is fixed and supported by adjusting the position of the lens support in the axial direction, and the lens that is provided on the second support plate and is in contact with the other end surface of the lens support. A second locking portion for restricting movement of the support in the other direction in the axial direction; and an upright standing from the first support plate or the second support plate near an end face of the lens support on the photoelectric conversion element side. An image reading device, comprising: a shielding portion protruding outside an effective optical path of the lens. 2. The image reading device according to claim 1, wherein the shielding unit is provided by a first shielding plate provided upright from the first support plate and a second shielding plate provided upright by the second support plate. An image reading apparatus comprising: a second shielding plate. 3. The image reading device according to claim 1, wherein a locking portion of the first locking portion or the second locking portion on a side where the photoelectric conversion element is provided is: An image reading apparatus comprising a part of the shielding unit.