JP3392155B2 - Digital image reader - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image reading in a reduction optical system for forming a reflected image from a document placed on a document table on an image sensor by a plurality of reflectors such as mirrors and an optical lens. The present invention relates to a device, and more particularly, to a digital image reading device for suppressing leakage of radio wave noise of a drive clock of an image sensor generated from an electric board on which the image sensor is attached and a frequency that is a constant multiple of the drive clock to the outside of the machine. is there.

[0002]

2. Description of the Related Art Conventionally, in a digital copying machine, an image scanner, a facsimile machine or the like, a digital reading device for reading an image of an original with an image sensor is used. In this digital reading device, for example, a CCD (charge coupled device) sensor is used as an image sensor, and the light and shade of a document image is converted into high and low electric signal levels.

FIG. 9 is a diagram schematically showing an example of an optical system of an image scanner portion of a copying machine using a digital reading device. As shown in FIG. 9, in the reduction optical system of the image scanner portion of this copying machine, the reflection image from the light source lamp 2 is reflected on the original document (not shown) placed on the original document table 1 by the three mirrors 3, An image is formed on the image sensor 7 by the lenses 4 and 5 and the optical lens 6. Then, the image sensor 7 is extended in the main scanning direction to simultaneously scan the lines in the main scanning direction of the document while the mirror 3,
The entire surface of the original is scanned by moving the optical lenses 4 and 5 and the optical lens 6 in the sub-scanning direction while satisfying the image forming conditions.

The image sensor 7 is attached to an electric board 8, and the electric board 8 has a position adjusting mechanism 9
The lens mounting table 10 is positionally adjusted by and is accurately mounted at a predetermined mounting position of the lens mounting table 10. Therefore, the image sensor 7 is accurately positioned so that the original image is accurately read, and a good resolution MTF (Modu) is obtained.
relation transfer function) characteristics are obtained.

Further, when flare light enters the image sensor 7, the image sensor 7 cannot read the original image accurately, so that the flare light shielding cover 11 covers the image sensor 7 and the main body of the machine M. 12 are provided.

[0006]

By the way, in such a reduction optical system, the image sensor 7 sets the reading timing by a certain driving clock.
The drive clock and radio waves having a frequency that is an integral multiple thereof are generated as radio noise. Then, this radio noise leaks out of the machine M.

In this case, the flare light shielding cover 11 partially shields the radio noise, but the cover 11 alone cannot sufficiently shield the radio noise. The reason is that the flare light shielding cover 1
This is because 1 is often formed of not only a metal but also a resin, and many of them are not conductive. Even if the flare light shielding cover 11 is made of metal, its surface is often black-painted or treated, and its conductivity is low in many cases. Further, since the flare light shielding cover 11 is provided for shielding the light, it is often provided only in a portion where flare light is likely to enter, and there are many gaps in terms of radio waves. . As described above, in the conventional digital image reading apparatus, the radio noise due to the driving clock cannot be sufficiently shielded.

In another digital image reading apparatus, the image sensor and the electric board for generating the driving clock are separated from each other to seal only the electric board, and the electric board is grounded, or noise of the generation source is reduced. For this reason, it is possible to use expensive ICs, but in the former case, it is necessary to reduce the S / N ratio between the image sensor and the electric board, and to take measures against noise between them. Had the problem of becoming expensive.

The present invention has been made in view of the above problems, and an object thereof is to prevent radio noise due to a drive clock generated from an electric board from leaking out of the machine M when the image sensor is driven. It is an object of the present invention to provide an inexpensive digital image reading device capable of sufficiently suppressing the above.

[0010]

In order to solve the above-mentioned problems, in the invention of claim 1, since the noise shielding cover covers at least the electric substrate, the image generated from this electric substrate. Radio noise that is a constant multiple of the frequency of the drive clock of the sensor is shielded. Therefore, it becomes possible to prevent the radio noise from leaking out of the machine.

Further, since the noise shielding cover is provided with a predetermined number of holes, even if the electric substrate is covered with the noise shielding cover, the heat generated from the electric substrate passes through these holes to shield the noise. You can effectively escape to the outside of the cover.

Further, since the noise shielding cover is disposed inside the flare light shielding cover, not only the noise shielding cover shields radio noise generated from the electric substrate, but also the flare light shielding cover. Will also be shielded, and leakage of radio noise will be further suppressed.

Moreover, since the flare light shielding cover is provided with a predetermined number of holes, even if the noise shielding cover is disposed inside the flare light shielding cover, it does not pass through the holes of the noise shielding cover. The heat generated by the electric board that escapes through the flare light shielding cover effectively escapes through the holes in the flare light shielding cover. In addition, since the hole of the noise shielding cover and the hole of the flare light shielding cover do not overlap with each other, even if holes are provided in both covers, flare light does not easily enter the image sensor.

Moreover, since the noise shielding cover covers the electric substrate in a non-contact manner, even if the noise shielding cover vibrates due to the vibration of the mounting portion of the noise shielding cover, the noise shielding cover is electrically connected. Since it does not come into contact with the substrate, vibration is not transmitted to this electric substrate.

In particular, according to the invention of claim 2, a gap formed between the lens mounting table of the optical lens and another member below the lens mounting table by the insertion member, and the lens mounting table and the flare light shielding. It is possible to suppress radio wave noise from leaking from at least one of the gaps between the cover and the cover.

Further, according to the invention of claim 3, since the insertion member is formed of a multi-contact type metal member having a small surface electric resistance or a member of which the surface of a non-conductive material is subjected to conductive processing, the radio wave Noise will flow from the machine body to the ground through the insert. Therefore, the radio noise is shielded even more effectively.

Further, according to the invention of claim 4, the noise shielding cover is formed of a metal member or a non-conductive member having a conductive processed surface, so that radio noise is transmitted through the noise shielding cover to the machine. It flows from the main body to the ground. Therefore, the radio noise is shielded even more effectively.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view similar to FIG. 9, schematically showing one embodiment of a digital image reading apparatus according to the present invention, and FIG. 2 is an exploded perspective view of an optical lens and an image sensor portion in this embodiment. The same components as those of the conventional digital image reading apparatus described above are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, a noise shielding cover 1
3 covers the position adjusting mechanism 9, the image sensor 7 and the electric board 8, and the flare light shielding cover 1 is provided.
1 is provided in the main body 12 of the machine M. In that case, the noise shielding cover 13 is provided in a non-contact manner so as to have a gap of 3 mm or less with respect to the position adjusting mechanism 9, the image sensor 7, and the electric substrate 8, and the mounting portion of the noise shielding cover 13 is Even if the noise shielding cover 13 vibrates and consequently the noise shielding cover 13 vibrates, the noise shielding cover 13 does not come into contact with the position adjusting mechanism 9, the image sensor 7 and the electric substrate 8 so that the vibration is not transmitted.

Further, in the gap formed between the tip of the noise shielding cover 13 and the position adjusting mechanism 9, a thin metal wire is rolled, or an insertion member made of an elastic material such as a rubber material or a urethane-based material. 14 has been inserted. The insertion member 14 is attached to the front end of the noise shielding cover 13, so that when the noise shielding cover 13 is attached, the noise shielding cover 13 can be easily positioned by abutting it on the position adjusting mechanism 9. It is designed to be installed. Further, the vibration from the IOT is transmitted through the noise shielding cover 13, but this vibration is absorbed by the insertion member 14 and thus is not transmitted to the position adjusting mechanism 9. As a result, the image reading of the image sensor 7 can be performed accurately.

Further, the insert member 14 made of an elastic material such as a rubber material or a urethane member is subjected to a conductive process, so that radio noise is transmitted to the ground through the insert member 14 and the main body 12 of the machine M. As a result, the radio noise is effectively shielded.

As shown in FIG. 2, the noise shielding cover 1
Reference numeral 3 denotes a metal member or a member obtained by subjecting a surface of a non-conductive material such as resin to conductive treatment, and has an L-shaped shielding portion 13a.
And side walls 13b provided at both ends of the shield 13a
And a mounting portion 13c formed continuously with the shielding portion 13a. Further, the plate thickness of the noise shielding cover 13 is set to 1 mm or less, which reduces the cost /
It has a weight advantage.

A large number of circular holes 13d are formed in the shielding portion 13a. The diameter of the hole 13d is set to 1/20 or less of the driving clock wavelength. Due to the large number of holes 13d, heat generated from the image sensor 7 can efficiently escape to the outside of the noise shielding cover 13.

Further, an opening 13e such as a notch or a hole through which the effective incident light passing through the optical lens 6 can pass is formed in the portion of the L-shaped shield 13a facing the optical lens 6.

The noise shielding cover 13 may cover only the electric board 8 by separating the image sensor 7 from the electric board 8. By doing so, the noise shielding effect is improved. Further, the noise shielding cover 13 can cover the optical lens 6 as well.

As shown in FIG. 3, the flare light shielding cover 11 includes a main body 11a, left and right side walls 11b, and a front wall 1.
It consists of 1c. Many holes 11 are formed in the main body 11a.
d is provided. With these many holes 11d,
The heat generated from the image sensor 7 that has escaped from the hole 13d of the noise shielding cover 13 can efficiently escape to the outside of the flare light shielding cover 11. In that case, as shown in FIG. 1, the flare light shielding cover 11 is used.
The hole 11d and the hole 13d of the noise shielding cover 13 are arranged so as not to overlap in the vertical direction. By arranging the holes 11d and 13d in this way, flare light is less likely to enter the image sensor 7. Further, as shown in FIG. 4, an insertion member 15 is inserted in the gap between the front wall 11c of the flare light shielding cover 11 and the lens mounting table 10. As shown in FIG. 5, the insertion member 15 is continuously formed by a predetermined number of a metal having a small surface electric resistance or a member whose surface is processed to be conductive, and the insertion member 15 is in contact with the front wall 11c at a plurality of positions. It is a contact type. As a concrete material of the insertion member 15, for example, a spring or urethane-shaped member made of a thin plate member having a restoring property is preferable. Further, as shown in FIG. 1, the insertion member 15 is also inserted in the gap between the lens mounting table 10 and the main body 12 of the machine M below the lens mounting table 10.

In the digital image reading apparatus of this embodiment having the above-described structure, the noise shielding cover 13 shields the radio noise generated from the electric board 8 and is an integral multiple of the frequency of the drive clock of the image sensor 7. Leakage to the outside of the noise shielding cover 13 is suppressed. Also,
Radio wave noise tries to leak from the gap between the tip of the noise shielding cover 13 and the position adjusting mechanism 9. However, this radio wave noise flows to the ground through the insertion member 14 and the main body 12 in this gap. Is effectively shielded.

Further, the radio noise leaking from the noise shielding cover 13 is shielded by the flare light shielding cover 11, so that the radio noise is prevented from leaking out of the machine M. Further, radio noise that is about to leak from the gap between the lens mounting table 10 and the main body 12 and the gap between the noise shielding cover 13 and the lens mounting table 10 causes the insertion member 15 and the main body 12 located in these gaps. Since it flows through to the ground, radio noise is effectively shielded. In this way, the leakage of radio wave noise generated from the electric board 10 to the outside of the machine M is significantly reduced.

FIG. 6 is a sectional view similar to FIG. 1, showing another embodiment of the present invention. In the above-described embodiment, the flare light shielding cover 11 is attached to the main body 12 of the machine M, whereas in this embodiment, it is provided on the lens mounting table 10 as shown in FIG. Therefore, a part of the noise shielding cover 13 is a flare light shielding cover 1.
However, the other part is located outside the flare light shielding cover 11. FIG. 7 shows the noise shielding cover 13 used at this time.

When the noise shielding cover 13 is mounted on the lens mounting table 10 as in this embodiment, the IOT (Im
Vibration such as age Output Terminal) is caused by IIT (Image Input)
It will not be transmitted to the noise shielding cover 13 from the bottom of the terminal) frame. Therefore, it is not necessary to insert the insertion member 14 such as urethane for vibration prevention into the gap between the noise shielding cover 13 and the position adjusting mechanism 9, and as shown in FIG. By firmly fixing the adjusting mechanism 9 to the screw or the like, it becomes possible to prevent noise more reliably. Moreover, since the insertion member 14 can be omitted, the cost can be reduced. The other structure and the function and effect of this embodiment are the same as those of the above-mentioned embodiment.

[0031]

As is apparent from the above description, according to the present invention, when driving the image sensor, it is possible to sufficiently suppress the radio noise due to the driving clock generated from the electric board from leaking out of the machine. You can Further, since it is sufficient to simply provide the noise shielding cover and the insertion member, the radio noise shielding mechanism of the digital image reading device can be formed at low cost. Further, since the noise shielding cover has a predetermined number of holes formed therein, even if the electric substrate is covered with the noise shielding cover, the heat generated from the electric substrate is prevented.
It is possible to effectively escape to the outside of the noise shielding cover through these holes. Further, since the noise shielding cover is arranged inside the flare light shielding cover, not only the noise shielding cover can shield the radio noise generated from the electric board, but also the flare light shielding cover can shield it. Therefore, leakage of radio wave noise can be further suppressed. Further, since a predetermined number of holes are formed in the flare light shielding cover, even if the noise shielding cover is arranged inside the flare light shielding cover, it escapes through the holes of the noise shielding cover. The heat generated from the incoming electrical board can be effectively dissipated to the outside of the flare light shielding cover through these holes of the flare light shielding cover, and also the noise shielding cover hole and the flare light shielding cover. Since the holes of the covers do not overlap with each other, even if holes are provided in both covers, it is possible to prevent flare light from entering the image sensor. Further, since the noise shielding cover covers the electric board in a non-contact manner, even if the noise shielding cover vibrates due to vibration of the noise shielding cover mounting portion, the noise shielding cover contacts the electric board. Therefore, it is possible to prevent the vibration from being transmitted to the electric board.

[Brief description of drawings]

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

FIG. 2 shows a noise shielding cover used in this embodiment, (a) is a plan view thereof, (b) is a front view thereof,
(C) is the left side view.

3A and 3B show a flare light shielding cover used in this embodiment, FIG. 3A is a plan view thereof, FIG. 3B is a front view thereof, and FIG. 3C is a right side view thereof.

FIG. 4 is a view showing that an insertion member is arranged in a gap between a flare light shielding cover and a lens mounting table.

FIG. 5 is a perspective view showing this insertion member.

FIG. 6 is a sectional view similar to FIG. 1, showing another embodiment of the present invention.

FIG. 7 shows a noise shielding cover used in this embodiment, (a) is a plan view thereof, (b) is a front view thereof,
(C) is a left side view thereof, and (d) is a right side view thereof.

FIG. 8 is a sectional view partially showing a modification of the embodiment shown in FIG.

FIG. 9 is a sectional view schematically showing a conventional digital image reading device.

[Explanation of symbols]

1 ... Original platen, 2 ... Light source lamp, 3, 4, 5 ... Mirror,
6 ... Optical lens, 7 ... Image sensor, 8 ... Electrical substrate,
9 ... Position adjusting mechanism, 10 ... Lens mounting table, 11 ... Flare light shielding cover, 11d ... Hole, 12 ... Main body, 13 ... Noise shielding cover, 13d ... Hole, 14 ... Insert member, 15 ...
Insert, M ... Machine

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-4-70249 (JP, A)                 JP 60-126958 (JP, A)                 Actual Kaihei 4-50970 (JP, U)

Claims (4)

(57) [Claims] 1. A plurality of reflectors for transmitting an original image illuminated by an illuminating device, an optical lens for forming an image of the original image transmitted from the reflectors, and an image formed by the optical lens. A digital image reading apparatus comprising an image sensor for converting an image into an electric signal, and an electric substrate driven by a clock signal of a specific frequency when the image sensor is driven, wherein the image sensor reads the original image with the image sensor. Is attached to the electric board, has a predetermined number of holes for radiating heat generated from the electric board, and eliminates noise caused by the clock signal.
A noise shielding cover that shields at least the electric board should prevent vibration transmission from the noise shielding cover.
Ku with are provided so as to cover a non-contact, to prevent the flare light from entering the image sensor,
A flare light shielding cover having a predetermined number of holes for radiating heat generated from the electric board is provided, and the noise shielding cover is provided between the flare light shielding cover and the electric board. A digital image reading apparatus, characterized in that the hole of the noise shielding cover and the hole of the flare light shielding cover are arranged so as not to overlap with each other. 2. A front Symbol of the gap between the lens mounting table of the optical lens and the cover flare light shielding and formed gap and the lens mounting base between the other member under the lens mounting table at least one digital image reading apparatus according to claim 1, wherein the insertion member is inserted. Wherein the insertion member, according to claim 2, characterized in that the surface conductive processing of small metallic members or non-conductive material of the surface electric resistance of the multi-contact type is formed from a member which has been subjected The digital image reading device described. Wherein said noise shielding cover, claims 1, characterized in that the surface conductive working metal members or non-conductive material is formed from a member that has been subjected to a 3 or 1 according Digital image reader.