JP3445240B2 - 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 a copying machine for reading an image of a document and copying the image information, and an image reading apparatus for inputting the image information.

[0002]

2. Description of the Related Art FIG. 6A shows a schematic view of an optical system of a copying machine for explaining a conventional example.

Reference numeral 1301 denotes a light source for illuminating the original 1303,
Reference numeral 1302 is a platen glass, 1305 is a reflection mirror that reflects the light beam 1304 reflected from the original 1303 and directs it to the lens 1306, and 1307 is a second reflection mirror that reflects the light beam 1304 emitted from the lens to the photosensitive drum 1308. Reference numeral 1311 denotes a lens base on which the lens is placed, and the lens is arranged on this base.

Here, the platen glass 1302 is moved from a in the direction of arrow b, and the photosensitive drum 1308 is rotated in the direction of arrow d while illuminating the portion c with the light source 1301, and in an electrophotographic process (not shown). Embodied on paper.

At this time, on the rotating photosensitive drum 1308,
Two reflection mirrors 130 that pass through the lens 1306 and
If a light beam other than the effective light beam 1304 reflected at 5, 1307 is emitted, a good image cannot be obtained.

For example, the lens 1 is mounted on the upper surface of the lens stand 1311.
When the light flux from 306 is reflected and the reflected light 1340 irradiates the surface of the drum 1308, flare occurs, and the flare overlaps the effective image light flux, and the image contrast may be extremely low and the image quality may be deteriorated. As for the flare, the contrast decreases as the amount of light is larger than that of the effective luminous flux.

Conventionally, in order to reduce such reflected light (flare), paint having a reflectance lower than the surface of the lens base 1311,
For example, there is one in which a black matte paint is applied to the surface of the lens base 1311.

FIG. 6B shows another example of the conventional example.

The lens 1360 is a zoom lens, and is engaged so as to be movable left and right in the drawing so that the copy magnification can be changed. (The zoom lens of the copying machine and the moving technology of the lens are not described here because they are already known techniques.) The lens 1360 is located at the position 136 during the enlargement copy.
Move to 1. The flare that tends to occur at this time is 1341. Further, the lens 1362 is a lens position when performing reduction copying, and at this time flare light 1342 is likely to occur.

In order to reduce the occurrence of flare, an antireflection member (for example, black sponge) is provided on the upper surface of the lens base 1311 and the lower surface of the lens hood, and black coating is performed.

FIG. 7 shows still another example of the conventional example. FIG. 7 shows the image forming arrangement of the optical system as viewed from above in the conventional example of FIG.
The lens at the same magnification is at the position of 1306, and it is 130
Move to position h at 6 '. At this time, the light ray indicated by 1343 becomes flare light. This flare light increases as the magnification increases.

Conventionally, the member 1343 in the light advancing direction is shaded by coloring it black. As another method, FIG.
The method as shown in FIGS. 8A and 8B was adopted.

That is, a black mylar 1369 'for fixing one end to the lens barrel 1306 or a black bellows 136.
9 is provided so that flare light (for example, 1343 in FIG. 7 ) is blocked as the lens 1306 moves.

Further, FIG. 9A is an enlarged view of a cross section of the bellows 1369. The material is made of a black resin or the like having a low transmittance so as not to transmit the light flux, and the surface is formed with a plurality of thin rectangular light-shielding line reflection shapes.

[0015]

However, in the case of the above-mentioned prior art, the following problems have occurred.

1: Anti-reflection coating, after the treatment process of coating,
A drying process is required, and the drying time and the space for drying become large, which is inevitably expensive in the manufacturing process.

2: The antireflection coating is effective because the coating may peel off over time and the antireflection effect does not continue, and the peeled coating floats inside the apparatus and adheres to other members such as mirrors. It may block the image light flux and deteriorate the image quality.

3: The light-shielding line on the surface of the conventional light-shielding plate has a ridgeline in a direction parallel to a tangent of a concentric circle having the optical axis of the lens 1306 as an axis, and is surrounded by the ridgeline and the valleyline. The “angle of the surface” may change due to the movement of the lens 1306 or the like, and the light flux transmitted through the lens 1306 at a certain specific magnification may be reflected before being directed to the reflection mirror 1307, resulting in flare light. It was

In order to prevent this, it is necessary to further change the surface angle of the antireflection light-shielding line member 1369 to make the angle acute as shown in FIG. 9B. However, when the light-shielding line is formed on the resin member. Had to make the resin substrate thicker in order to deepen the valley line. This means that more resin material is required, which is expensive and makes the device large and heavy.

Regarding the angular arrangement design of the surface of the light-shielding line, the frame member is arranged closer to the optical path due to the space saving of the optical system accompanying the miniaturization of the copying machine itself, and the degree of freedom in design is further reduced. However, antireflection design is becoming difficult.

As one of the multifunctional functions, the range of lens movement is widened as the zoom magnification is increased, the optical path is complicatedly moved, and a wide antireflection angle is required as an antireflection member, or an area where painting is required. Is becoming wider. Against this background, it is extremely difficult to deal with the problem in the conventional example.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image reading apparatus capable of reducing flare light with a simple and inexpensive structure. .

[0023]

In order to achieve the above object, the present invention provides an optical system for guiding reflected light from a document and an optical system provided around the optical path of the optical system, which has the optical path side.
Center and the proof instrument shielding light member diffused reflection inside the device of the reflected light by wavy shape formed, in the image reading apparatus having a, a ridge line of the wavy shape of the light blocking member, an optical axis of the optical system for concentrically circle characterized by being formed obliquely.

As a result, the light flux radiated and reflected on the wavy shape of the light shielding member is directed in the direction away from the optical axis, so that it is not directly radiated on the photosensitive member. Therefore, it is possible to prevent image deterioration. Therefore, the amount of reflected light can be reduced even with a member having a higher reflectance than in the past, and thus it is possible to use a cheaper material.

Further, a ridge line, the angle between <br/> concentric circle centered on the optical axis of the optical system, is preferably in the range of approximately 20 to 70 degrees, and more preferably, approximately 30 The range of 60 to 60 degrees is preferable. The oblique relative angle between the concentric circles of the ridge line of the corrugated shape by setting the above angle, sufficient effect can be obtained.

Further, it is preferable to reinforce a part or the whole of the light shielding member with a rigid member.

Further, it is preferable to install by applying tension to the end portion of the light shielding member. By applying tension, it is possible to prevent loosening of the sheet, so it is possible to prevent accidents that block the effective optical path and obtain stable image quality.

Further, in order to make the length of the light shielding member variable according to the change of the position of the optical system, it is preferable to provide a winding means at the end of the light shielding member. When the winding means is provided, the winding space for preventing loosening is reduced, and the device can be downsized.

Further, by connecting the parallel side portions of the plurality of parallelogram sheet-shaped side edge members to each other , the wave of the light shielding member is formed.
A shape may be formed. When the edge members are attached,
Small fragments can be used effectively and resource waste can be reduced.

Further, concentric circle centered on the optical axis of the optical system
Two or more types of angles may be combined with the ridgeline .

As described above, according to the present invention, with a simple structure,
The image reading device itself is further miniaturized, image quality such as image homogeneity is improved, functions are expanded, energy saving, and cost reduction are also exerted.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
Unless otherwise specified, the material, the shape, the relative arrangement, and the like are not intended to limit the scope of the present invention thereto.

(First Embodiment) A first embodiment of the present invention is shown in FIG.

The ridge for concentric circle centered on the optical axis of the lens (not shown) in the optical path around a member to place a light shielding member having a diagonal shading lines. Incidentally, the place to place is the place where there was a problem in FIGS.

FIG. 1 shows an example of molding this light-shielding line on the surface of a resin plate or the like. Reference numeral 306 (see FIG. 2) is a lens as an optical system, 309 is a light blocking member, 310 is an optical axis of the lens, 31
2 is a tangential direction of a concentric circle of the optical axis 310, and 313 is one of ridge lines of the light shielding member 309. Ridge 313 of the light shielding member is formed to be about 30 degrees obliquely against the concentric circle of the optical axis 310 of the lens 306.

The ridge line 313 is arranged at an angle of about 30 degrees to 6 degrees.
If it is 0 degree, the flare light flux when used in the optical system of the copying machine can be almost attenuated to a level that does not cause image deterioration by the time it reaches the photosensitive drum.

That is, the light beam slightly reflected on the surface between the ridges is not immediately directed to the photosensitive drum 1308, but irradiates other members inside the apparatus and repeats reflection with diffusion and attenuation, It may reach the photosensitive drum 1308. However, even in this case, the light flux applied to the drum 1308 is sufficiently attenuated, which is not a problem.

For example, when the reflectance per one time when the member is irradiated and reflected is about 3%, the light amount is not sufficiently low with respect to the drum sensitivity, and even when the image quality is deteriorated, it is twice. When reflected, it becomes 3% × 3% = less than 0.1%, the reflected light (flare light) is sufficiently low, and the influence on image deterioration is not a problem.

[0039] (a alpha) angle between concentric circles of ridge 313 and the lens optical axis 310 of the light blocking member 309 is generally considered to be the best is approximately α = 45 °. The case of α = 0 ° is the conventional example itself. When α = 90 °, the ridgeline 313 of the light blocking member 309 is parallel to the lens optical axis 310, and there is no point in forming the light blocking member 309 as a light blocking line. Therefore, in order to sufficiently obtain the effect of the present invention, α
Is approximately 20 ° to 70 °.

On the other hand, when the optical system is provided with a function of magnification, each of the parts of the optical system changes its positional relationship according to the magnification change, so that the above-mentioned α is approximately 30 °.
It becomes 60 °.

In the image reading apparatus, in addition to optical parts such as a lens and a mirror, drive system parts such as a motor and a gear rail for driving them, various members such as a side wall, a bottom wall, and columns are arranged near the optical system. The positional relationship is different for each device. Therefore, the best α needs to be optimized for each device.

(Second Embodiment) A second embodiment of the present invention is shown in FIG. The optical system moves inside the device to change the magnification, and light shielding members 309a and 309b are provided so as to close the gap between the moving optical system (306 → 306 ′) and the fixed portion.

The light-shielding members 309a and 309b are diagonal light-shielding line antireflection members obtained by processing light-shielding lines having diagonal ridges on the surface as shown in FIG.

The light shielding member 309a, 309b is serving optics
The lens 306 is mounted movably lens 30
When moved to 6 (at the same magnification) or 306 '(at the time of enlargement), they move like light blocking members 309a' and 309b ', respectively.

FIG. 5 (a) shows a method of forming a light shielding member of the present invention, which is formed by pressing a sheet metal substrate.

In the figure, a indicates a press die (other parts of the press machine are omitted). As shown in the drawing, a has a pair of upper and lower undulating grooves formed in the front direction. The corrugations are configured to fit well when a is in the pressed state.

Reference numeral b is a rectangular sheet metal substrate, which is pressed by a and formed in a wavy shape. At this time, the sheet metal b is set at a predetermined angle with respect to the ridgeline of the press die and pressed to form the light shielding member of the present invention.

If the sheet metal substrate that has been blackened (painted in black) and has a light blocking effect is used, only the above-mentioned press work is required. On the other hand, when a sheet metal substrate having a bright metal surface is used, blackening treatment (black coating) is required after the press working.

FIG. 5B shows a method of forming a light-shielding member of the present invention, in which a sheet-shaped substrate is processed by passing it between a pair of rotating rollers a having an uneven surface.

In the figure, reference numeral a denotes a pair of rotating rollers, each of which has an uneven groove on its surface and rotates in the directions of the arrows. The distance between the two rollers can be maintained at about the thickness of the sheet substrate. Reference numeral b indicates a sheet-like substrate, which is forcibly passed between the rollers a and a wavy light-shielding line is formed.

The substrate material b is a thin metal plate, a resin sheet or the like. If the substrate material that is black and has a light blocking effect is used, only the above processing is required, but if the light blocking effect is not sufficient,
It is necessary to blacken after processing.

(Third Embodiment) A third embodiment of the present invention is shown in FIG.

In this embodiment, in the image reading apparatus in which the lens 306 moves according to the magnification change, the lens 306
End of the light shielding member 309 of the present invention the end portion is connected to, shielding
The other end of the light member 309 is connected to the winding device 315 (FIG. 3 is a sectional view).

The light shielding member 309 is made of resin and has a sheet shape. The ridge line of the corrugated shape of the light blocking member is formed by <br/> concentric circles with a predetermined angle of the lens optical axis.

The take-up device 315 as a take-up means includes a light-shielding portion.
A tension is applied to one end of the material 309 so that the material is always prevented from sagging.

(Fourth Embodiment) A fourth embodiment of the present invention is shown in FIG.

In this embodiment, the moving lens 306 is connected to the light blocking member 309 of the present invention. Shading part
Since the material 309 has a sheet shape and is not sufficiently strong, a reinforcing material 314a as a rigid member is used.

One end of the light blocking member 309 is fixed to the lens 306, and the other end is fixed by a fixing member 314b in the reading device. Reinforcement material 314a except at both ends
It is reinforced by. The reinforcing material 314a is formed of an elastic material and constantly applies tension to the light shielding member 309 to prevent slack.

(Fifth Embodiment) A fifth embodiment of the present invention is shown in FIG.

This embodiment shows one of the methods for forming the light shielding member of the present invention. This is a configuration in which parallel quadrilateral sheet-shaped cut-off members are bonded by connecting parallel sides. Figure 4
In (b), the light shielding member is formed by alternately joining two types of parallelograms. This forming method takes time to form, but it can be formed relatively easily without using a large press machine or mold, so it is suitable for when a large number of small quantities of various kinds are needed for the initial inspection of the light blocking member. It is a forming method.

[0061]

As described above, according to the present invention,
Since the light flux that has been applied to and reflected from the wavy shape of the light shielding member is directed away from the optical axis, it is not directly applied to the photoreceptor. Therefore, it is possible to prevent image deterioration.

Therefore, the amount of reflected light can be reduced even with a member having a higher reflectance than before, so that it is possible to use a cheaper material.

[0063] The oblique relative angle ridgeline and concentric circle <br/> the wavy shape of the light blocking member had sufficient effect be in a range of about approximately 20 to 70 °.

Further, when tension is applied, loosening of the sheet can be prevented, so that an accident of blocking the effective optical path can be prevented,
It is possible to obtain stable image quality.

Further, when the winding means is provided, the winding space for preventing loosening is reduced and the apparatus can be downsized.

When the edge members are attached to each other, small pieces can be effectively used and waste of resources can be reduced.

As described above, according to the present invention, with a simple structure,
The image reading device itself is further miniaturized, image quality such as image homogeneity is improved, functions are expanded, energy saving, and cost reduction are also exerted.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a main part of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a main part of an image reading apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a main part of an image reading apparatus according to a third embodiment of the present invention.

FIG. 4A is a schematic configuration diagram of a main part of an image reading apparatus according to a fourth embodiment of the present invention, and FIG. 4B is an image reading apparatus according to a fifth embodiment of the present invention. It is a principal part schematic perspective view.

FIG. 5 is a diagram showing a method of manufacturing the light shielding member of the image reading apparatus according to the embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of an image reading apparatus according to a conventional example.

FIG. 7 is a schematic configuration diagram of a main part of an image reading apparatus according to another conventional example.

FIG. 8 is a schematic perspective view of a main part of an image reading apparatus according to a conventional example.

FIG. 9 is a schematic configuration diagram of a main part of an image reading apparatus according to a conventional example.

[Explanation of symbols]

306 Lens (optical system) 309 Light-shielding member 313 Ridge line 314a Reinforcing material (rigid member) 315 Winding device (winding means)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Takemura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-57-171360 (JP, A) JP-A-59 -37507 (JP, A) JP-A-4-277770 (JP, A) Actually developed 62-109155 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/04 H04N 1/028 G06T 1/00 420

Claims (8)

(57) [Claims] 1. An optical system for guiding reflected light from a document, and an optical system provided around the optical path of the optical system and formed on the optical path side.
In the image reading apparatus and a proof member shielding the light member diffused reflection inside the device of the reflected light by wavy shape made, the ridge line of the wavy shape of the light blocking member, and an optical axis of the optical system image reading apparatus characterized by being formed obliquely against the concentric circle. And wherein said ridge line, the angle between <br/> concentric circle centered on the optical axis of the optical system, the image reading apparatus according to claim 1, wherein in the range of 20 to 70 degrees. And wherein the ridge, the angle between <br/> concentric circle centered on the optical axis of the optical system, the image reading apparatus according to claim 1, wherein in the range of 30 to 60 degrees. 4. The image reading apparatus according to claim 1, wherein a part or the whole of the light shielding member is reinforced with a rigid member. 5. The image reading apparatus according to claim 1, wherein the light shielding member is installed by applying a tension to the end portion. 6. A light shielding member corresponding to a change in position of an optical system
The image reading device according to claim 1, wherein a winding means is provided at an end portion of the light shielding member so that the length of the sheet can be varied. 7. A corrugated shape of a light-shielding member by connecting parallel side portions of a plurality of parallelogram sheet-shaped side edge members to each other.
The image reading device according to claim 1, wherein the image reading device has a shape . 8. The image reading apparatus according to claim 1, wherein two or more kinds of angles formed by a ridge and a concentric circle centered on the optical axis of the optical system are combined.