JPH10210221A - Picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of dust, noise and a difference in the coefficients of thermal expansion by means of using a heat radiating member and to improve the assembly workability of a sensor substrate containing a heat radiating board in CCD heat countermeasure. SOLUTION: CCD(charge coupled device) 9 is fitted on a PCB(printed circuit board) substrate 13 and a CCD substrate 19 is constituted at the minute part of the peripheral part of a lens unit 16. The CCD substrate 19 is fixed and supported on the back side of a bracket 18 formed in an almost U-form viewed from a side by a screw and the like. The backside of CCD 9 is brought into contact with the CCD 9 fitting side of the PCB substrate 13. The heat radiating board 20 is pressed from both sides of CCD 9 and the PCB substrate 13, and CCD 9 is directly soldered and fixed to the PCB substrate 13 in such state. The face of the heat radiating board 20 which touches the backside of CCD 9 is desirably larger than (at least equal to) the backside of CCD 9 in terms of an area, and heat radiating effect can be expected.

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, and more particularly to an image reading apparatus such as an image scanner, a digital copying machine, and a facsimile.

[0002]

2. Description of the Related Art Generally, in a digital image reading apparatus using a light receiving element such as a CCD, an original is illuminated, and reflected light from a predetermined reading line is guided to the CCD by an optical system such as an image forming lens. An image is formed, the image is decomposed into pixels of a predetermined size by a CCD, and each pixel is photoelectrically converted to form an image signal. By the way, such a recent image reading apparatus of a reduction optical system using a CCD and an image forming lens is capable of achieving high resolution such as 400 dpi or 600 dpi for an A3 size document and a reading linear speed of 200 mm.
/ S or more. In order to achieve both high resolution and high speed, it is necessary to use a CCD having 5,000 to 7,500 pixels and drive the CCD at a high driving speed of several tens of MHz.

However, along with this, the amount of self-heating of the CCD also increases, and the temperature gradient of the heating temperature also increases, deteriorating CCD characteristics such as dark current, transfer efficiency, and output level difference between odd and even channels. This causes the quality of the read image to deteriorate. More specifically, an increase in dark current has a large effect on the image, such as a decrease in S / N, a decrease in transfer efficiency has a decrease in MTF, and an increase in the output level difference between odd and even channels has the effect of generating vertical stripes. In particular, the relationship between the dark current and the CCD temperature is known as a physical phenomenon, and is described in a data sheet or the like for each of various CCDs.

FIG. 9 is a diagram showing an example of the dark output characteristics of the CCD as described above. As for the temperature,
The increase in the amount of illumination for achieving both high resolution and high speed raises the temperature inside the apparatus, and this temperature is further added to the CCD temperature. Therefore, to perform high quality image reading, C
One point is to use a part with good CD characteristics, that is, to use a CCD at a temperature as low as possible.

Conventionally, various methods of radiating and cooling heat have been devised and applied as a measure against the heat of the CCD.
For example, Japanese Unexamined Patent Application Publication No.
Although the configurations described in 207256 and JP-A-8-102822 are different from each other, basically, the temperature of the CCD is controlled to be kept constant by the wind of a fan. Other methods include heat radiation using a holding member as disclosed in JP-A-3-27664 and JP-A-4-207.
As in the second embodiment of JP-A-256-256, there is a temperature control using a Peltier element.

[0006]

However, the method using a fan involves the use of an optical component such as an imaging lens or a mirror or a CC.
This causes dust to adhere to the surface of D and causes a problem of noise. In addition, the method of dissipating heat to the holding member requires that the entire holding member be made of a metal material having high thermal conductivity such as aluminum or copper, which is contrary to the current mainstream molding (low cost, light weight). In addition, holding member and CC
D is fixed, so that a difference in thermal expansion coefficient between the two causes CC
D causes distortion and misalignment. The method using the Peltier element is impractical at the current cost unit price.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in the countermeasures against the heat of the CCD, it is possible to solve the problems of dust, noise, the difference in the coefficient of thermal expansion due to the use of the heat radiating member, and the like. To provide an image reading device that improves the operability of assembling the sensor board including: a. Providing an image reading device with an improved CCD heat radiation effect; and more securely mounting the CCD heat radiation plate. , CC
To provide an image reading device that eliminates stress (load) on D. • To further improve the heat radiation effect and to provide an image reading device that considers the problem of dust. To provide an image reading device that can be assembled and to downsize the sensor substrate including the heat radiating plate.Provide an image reading device that has a simple configuration, is easy, and can be expected to have a heat radiating effect at no cost. It is done for the purpose of doing, etc.

[0008]

According to a first aspect of the present invention, there is provided a light receiving sensor mounted on a circuit board by illuminating a document by illuminating means and using an image forming element to emit a light beam containing information to be read from the document. In the image reading apparatus for projecting and forming an image on a substrate, a heat sink having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and at least the back surface of the light receiving sensor and the heat sink are in contact with each other. Contact,
Alternatively, the light receiving sensor is soldered and fixed on the circuit board while holding and holding the heat radiating plate so as to contact with the heat conductive material.

According to a second aspect of the present invention, an original is illuminated by an illuminating means, and a light beam containing information to be read from the original is projected and imaged by an imaging element on a light receiving sensor mounted on a circuit board. In the image reading device, a heat radiating plate having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and at least the back surface of the light receiving sensor abuts on the heat radiating plate, The light receiving sensor is mounted on the circuit board so that a ventilation space is provided between the heat radiating plate and the circuit board, and the light receiving sensor is mounted on the circuit board so that a ventilation space is provided between the heat sink and the circuit board. It is what it was.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a regulating portion for regulating a displacement of the heat radiating plate is provided in a part of the heat radiating plate, and the regulating portion is provided at a position in a thickness direction of the circuit board. The light receiving sensor is mounted on the circuit board while applying the portion.

According to a fourth aspect of the present invention, an original is illuminated by an illuminating means, and a light beam containing information to be read from the original is projected and imaged by an imaging element onto a light receiving sensor mounted on a circuit board. In the image reading device, a heat radiating plate having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and a surface of the heat radiating plate facing the light receiving sensor is a rear surface area of the light receiving sensor. And at least a part of the heat radiating plate extends from the circuit board and extends to a ventilation space in the image reading apparatus.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a ventilation hole for outside air is provided in a part of the image reading device, and a part of the heat radiation plate extends so as to face the ventilation hole. It is characterized by having.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the heat radiation plate extending from the circuit board and a component constituting the image reading apparatus are provided between A heat conductive member which is flexible and has high heat conductivity is interposed therebetween so as to be in contact with both the extending portion of the heat sink and the constituent members of the image reading apparatus.

According to a seventh aspect of the present invention, an original is illuminated by an illuminating means, and a light beam containing information to be read from the original is projected and imaged by an imaging element onto a light receiving sensor mounted on a circuit board. In the image reading device, a heat sink having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and the heat sink and the circuit board can be fixed to each other by soldering. The heat sink and the circuit board are soldered and fixed, and the light receiving sensor is mounted on the circuit board.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below by taking an image reading apparatus using a CCD line sensor as an example. FIG.
1 is a schematic configuration diagram of an image reading apparatus to which the present invention is applied. As is well known, a reduction optical system is configured in a main body 1 of the image reading apparatus. More specifically, an original (not shown) is placed on a contact glass 2 serving as an original table, and the original is illuminated by a light source 4 located below the original. Second mirror 6, third
The light is sequentially turned back by the mirror 7, and then condensed by the lens 8 through the filter 12 for color correction and the like, and
Is projected and imaged. At this time, the light source 4 and the first mirror 5 constitute a first traveling body 10, and the second mirror 6 and the third mirror 7
Constitute the second traveling body 11. As an actual reading operation, the first traveling body 10 and the second traveling body 11 connected to driving means (not shown) are moved at a speed ratio of 1: 1/2 in the direction of the arrow (sub-scan) in the figure. That is, at the same time, two-dimensional scanning is performed by scanning the CCD 9 in the main scanning direction. The PCB board 13 is a circuit board for driving the CCD 9 and outputting a read signal.
9 are attached. The scanner board 14 installed in the rear portion processes the signal from the PCB board 13 and transfers the signal to an IPU (image processing unit), and controls the rotational speed of the motor of the traveling body drive source according to the magnification. Is a circuit board for performing the following. Further, a filter 12, a lens 8, a CCD 9
Are integrally mounted on the lens holder 15,
The lens unit 16 is constituted. The lens unit 16 and the scanner substrate 14 are covered with a light-shielding cover 17 to prevent disturbance (such as flare light and dust) from entering. Reference numeral 3 denotes a cooling fan for preventing an increase in the temperature inside the device due to the illumination light of the light source 4, and outside air that has passed through dustproof means is taken into the device.

(Inventions of Claims 1 and 4) In the image reading apparatus as shown in FIG. 1, first, an embodiment according to Claims 1 and 4 will be described. FIG. 2 shows the details of the periphery of the lens unit 16 shown in FIG.
The CCD 9 is mounted on the substrate 3 to form a CCD substrate 19. The CCD board 19 is fixedly supported by screws or the like (not shown) on the back side of a bracket 18 formed substantially in a U shape when viewed from the side. Bracket 18 is C
This is for adjusting the optical position of the CD 9 to an ideal position, and a part of the rear portion of the lens holder 15 is inserted into the U-shape of the bracket 18. Further, a position adjusting mechanism of the CCD 9 is provided between the bracket 18 and the lens holder 15.

In FIG. 2, the position adjusting mechanism is omitted for easy viewing, but in actuality, an adjusting mechanism for the main, sub-scanning, optical axis direction, rotation direction and the like is provided as required. Here, in the present invention, a heat radiating plate is used as a countermeasure for heat of the CCD 9, but the heat radiating plate can be provided without a conventional problem such as a difference in thermal expansion coefficient and a stress on the CCD 9. That is, in the present invention, as shown in FIG.
A heat sink 20 is interposed between the heat sink 20 and the substrate 13.
D9 so that the mounting side surface is in contact,
D9 is pressed down from both sides of the PCB board 13, and the CCD 9 is directly soldered and fixed to the PCB board 13 in this state.
The case of the CCD 9 is usually made of ceramics and a cover glass, but the ceramic part, especially the back surface having the largest area, is the most effective and effective part for absorbing heat from the CCD 9.

Therefore, the heat radiating plate 2 in contact with the back surface of the CCD 9
The surface of 0 is desirably larger (at least equivalent) in area than the back surface of the CCD 9, and a higher heat dissipation effect can be expected. Although the CCD 9 is completely fixed to the PCB substrate 13 by soldering, the heat radiation plate 20 is held only by the holding force sandwiched between the CCD 9 and the PCB substrate 13. The heat radiating plate 20 is made of aluminum or copper material having high thermal conductivity, but has a large coefficient of thermal expansion. Conventionally, this has been a problem. However, as described above, in the present invention, the CCD 9 and the radiator plate 20 are not fixed, but are only pressed and contacted.
Even if the radiator plate 20 expands due to the temperature rise of the CCD 9, the CC
It does not affect D9.

In order to further improve the heat radiation efficiency, the CCD 9 and the heat radiation plate 20 such as silicone oil, silicone rubber, polyimide film, and flexible heat conductive tape are not fixed between the CCD 9 and the heat radiation plate 20. The back surface of the CCD 9 and the radiator plate 20 are completely brought into close contact with each other via the heat conductive material. In addition, on the contact surface between the heat radiating plate 20 and the PCB board 13, there is no problem if the circuit wiring arranged on the PCB board 13 is not electrically connected with the heat radiating plate 20. Is the heat sink 20 and PC
It is necessary to take an insulation measure such as interposing an insulating member such as a phenol resin between the B substrate 13 and performing insulation treatment on the surface of the heat sink 20. As described above, since the heat radiating plate 20 is sandwiched and installed at the same time as the soldering of the CCD 9 to the PCB substrate 13, the three components can be integrated and handled as the CCD substrate 19 with the heat radiating plate 20 without the conventional problem. .

Regardless of the shape of the heat radiating plate 20, the CCD 9 is effective in suppressing the heat generation temperature and making the temperature gradient uniform to some extent by merely attaching the heat radiating plate. For example,
The heat radiating plate 20 may be only the vertical portion 20a sandwiched between the CCD 9 and the PCB substrate 13. But one side is P
Since it is almost in close contact with the CB substrate 13, the function of heat dissipation is hindered, the efficiency is low, and a great effect cannot be expected. There is no problem if the surface area of the vertical portion 20a can be made as large as possible, but the space of the device is limited, and there is almost no extra space in the device which tends to be compact. Therefore, it is actually difficult to simply enlarge the vertical portion 20a.

Therefore, in the present invention, even in a device having no extra space available for heat dissipation, a decrease in heat dissipation efficiency due to the PCB substrate 13 or the like is prevented, and the heat dissipation effect is improved. For example, as shown in FIG. 2, the shape of the heat sink 20 is L-shaped when viewed from the side, and the upper part of the vertical portion 20a is P-shaped.
The heat radiation portion 20b was provided by extending from the CB substrate 13 and bending between the upper portion of the PCB substrate 13 and the light shielding cover 17. The heat radiating portion 20 b extends in a direction (sub-scanning direction) parallel to the moving direction of the traveling body and projects into a space along the light shielding cover 17. The space is a ventilation space for heat radiation of the scanner substrate 14 (FIG. 1), and the heat radiation part 20b is exposed to the air in the space to make the heat radiation work smoothly and further promote the heat radiation. In the embodiment, the radiator 2
0b has been described with the L-shaped heat radiating plate 20 extending in the sub-scanning direction. However, the shape of the heat radiating plate 20 is not limited, and the present invention is applicable to any shape according to the space of the device. Of course, it is needless to say that the effect is increased if the surface area of the heat radiating portion 20b is made as large as possible.

(Invention of Claim 5) As a continuation of the above embodiment, the invention of claim 5 will be described with reference to FIG.
Normally, near the circuit board on which a heat-generating IC such as the scanner board 14 is mounted, a ventilation hole 21 for releasing the heat to the outside is provided (in FIG. 3, it is opened in the right side plate of the main body 1). There). The heat from the heat radiating portion 20b in the heat radiating ventilation space of the scanner substrate 14 also
It is released outside through Therefore, if the heat radiating portion 20b can be installed as close as possible to the ventilation hole 21, the heat radiating effect is further improved. Moreover, if a cooling fan is provided in the ventilation hole 21, the effect becomes remarkable. However, releasing heat to the outside means introducing outside air into the apparatus. Therefore, no matter how much dust protection measures are taken, the problem of dust is inevitable, and the problem becomes more apparent when a cooling fan is used.

Therefore, in the present invention, the heat radiation effect is improved, and the problem of dust can be reduced. For example, as shown in FIG. 3, the shape of the heat radiating plate 20 is U-shaped when viewed from the side, and the heat radiating portion 20b of the heat radiating plate 20 shown in FIG.
Another bent portion was provided at the right end of the device, and the heat radiating portion 20b 'was also extended downward. Then, the surface of the heat radiating portion 20 b ′ extending downward is made to face the ventilation hole 21. Further, the gap between the light shielding cover 17 and the upper part of the heat radiating portion 20b was also made small. Then, the air (wind) flowing in the direction of the CCD 9 becomes small, dust can be suppressed as much as possible, and heat can be efficiently released from the ventilation hole 21 together with the radiation of the scanner substrate 14 by the radiation part 20b 'extended downward. . This is especially true if the cooling fan is used to directly blow air to the heat radiation portion 20b 'extending downward. Although there is a concern about the dust problem, the wind from the cooling fan once hits the radiating portion 20b 'extending downward, and is blocked.
Dust inflow into the CD 9 is not a problem. In order to further enhance the heat radiation effect including the scanner substrate 14, a ventilation hole dedicated to the radiation of the CCD 9 is provided separately from the ventilation hole 21, and the radiation extending downward just before the ventilation hole and opposite thereto is provided. The portion 20b 'may be located. Further, if a cooling fan is provided, the dust-proof effect is the same and the heat-dissipating effect is further improved.

(Invention of Claim 2) FIG. 4 is a structural view of an essential part for explaining an embodiment of the invention according to claim 2, wherein the heat radiating plate 20 has the L-shape shown in FIG. Used. In the present embodiment, as shown in FIG.
2, but is not sandwiched between the CCD 9 and the PCB substrate 13 as in the embodiment of FIG. To avoid contact.
That is, the heat radiating plate 20 is attached only to the CCD 9. Although the mounting method has been described with reference to FIG. 2, a leaf spring or a flexible heat conductive tape, which is an elastic member, is used in consideration of thermal expansion. Pins are inserted into the CCD 9 to which the heat radiating plate 20 is attached and the socket 22 for the CCD 9 provided on the PCB board 13 and attached. Then, the heat radiating plate 20 and the PCP board 13 are separated by the height of the socket 22, and a space is formed therebetween.
Since the space can be used as a ventilation space, it is possible to further improve the heat radiation efficiency. The means for separating the heat radiating plate 20 from the PCB substrate 13 and attaching the CCD 9 to the PCB substrate 13 is not limited to the method using the socket 22. For example, the PCB substrate 13 and the heat radiating plate 20
And make a space between it and CC board 13
D9 may be directly soldered and fixed. Also,
If the configuration of the fourth and fifth aspects of the present invention is added to the configuration of the present invention, a further heat radiation effect can be expected.

(Invention of claim 3) For example, in the invention of claim 1 shown in FIG. 2, the heat radiating plate 20 is held only by the holding force by soldering the CCD 9 and the PCB substrate 13, When vibration with a force larger than the holding force or an unexpected external pressure is applied to the plate 20, the radiator plate 20 easily moves (particularly, the amount of downward displacement increases). If the displacement increases, the worst case is that the radiator plate 20
Contact with the pins 9 to cause an electrical short and destroy the CCD 9. Claim 2 shown in FIG.
In the present invention, since the radiator plate 20 is attached only to the CCD 9, even if the radiator plate 20 is slightly touched,
The optical position of D9 will be shifted. Further, all the weights of the radiator plate 20 are applied to the pins of the CCD 9 and the direction of the engagement is in the direction of falling to the CCD 9 side.
Problems such as deformation of the pin 9 and removal from the socket 22 occur. Therefore, in the invention of claim 3, the displacement of the heat radiating plate 20 is restricted and the weight load on the CCD 9 is reduced.
The above problem is prevented from occurring.

FIG. 5 is a schematic view of a main part for explaining an embodiment of the third aspect of the present invention. As shown in FIG. At both ends (front and back sides of the paper) of 20b, stopper portions 20c are provided, which are partially bent toward the PCB substrate 13 side. The stopper portion 20c is composed of a heat radiation plate 20 and a CCD 9 and a PCB substrate 1.
3, when it is held and held, it contacts the thickness portion 13a of the upper part of the PCB substrate 13, thereby restricting the movement of the heat sink 20 in the downward direction and the rotation direction (around the optical axis),
9 is prevented.

Further, since the heat radiating plate 20 is put on the PCB substrate 13 by the stopper portion 20c, the weight of the heat radiating plate 20 is entirely applied to the PCB substrate 13. Therefore, the CCD 9 is not subjected to any stress. Even if the weight of the heat radiating plate 20 is applied to the PCB substrate 13, the PCB substrate 13 is applied in a direction in which the load is strong, so that the PCB substrate 13 does not bend and deform. If the shape and the position of the stopper portion 20c provided on the heat sink 20 are devised, it is possible to prevent not only the displacement in the downward direction and the rotation direction but also the displacement in the upward direction and the left and right direction. The displacement regulation and weight reduction means for the CCD 9 are not limited to the illustrated embodiment, but may be any configuration and method as long as they are constituted by the PCB substrate 13 and the heat sink 20. For example, instead of providing the stopper portion 20c specially as described in the above embodiment on the heat radiating plate 20, the (radiating portion) of the heat radiating portion 20b is directly connected to the PCB substrate 1.
A similar result can be obtained even if the third portion 13 is brought into contact with the portion 13a in the thickness direction. Further, in the invention of claim 2 shown in FIG. 4, for example, a portion having the same shape as the stopper portion 20c is provided on the heat sink 20 and the stopper portion 2c is provided.
What is necessary is just to extend it until 0 c contacts the PCB substrate 13.

(Invention of claim 6) The heat radiating plate 20 as a measure against the heat generation of the CCD 9 and the temperature gradient is shown in FIG.
By dividing the CCD 9 into a portion that absorbs and transmits the heat of the CCD 9 (vertical portion 20a) and a portion that emits the absorbed heat (the heat radiating portion 20b), the device can efficiently operate even in a space-less device. Heat can be dissipated. However, the heat radiating portion 20b alone is not sufficient as a countermeasure against heat generation associated with a higher speed driving of the CCD 9 which is expected in the future, and the heat radiating plate 20 itself may become a heat generating element because heat cannot be completely radiated. However, there is a limit to the size of the heat radiation portion 20b. Therefore, in the present invention, even if the heat amount larger than the heat dissipation capacity enters the heat sink 20, the heat is absorbed by the apparatus main body 1 via the flexible heat conductive member.

FIG. 6 is a diagram showing the construction of a main part of a sixth embodiment of the present invention. As an example, an embodiment using a thin copper plate 23 as a flexible heat conductive member is shown. The thin copper plate 23 is fixed at its center to the upper part of the heat radiating portion 20 b, and both end portions are provided so as to be in contact with the back side of the light shielding cover 17. At this time, the thin copper plate 23 is brought into contact with the light-shielding cover 17 in a wide range and in a pressed state so that heat transfer proceeds efficiently and smoothly. Needless to say, the thin copper plate 23 may be fixed to the light shielding cover 17 side. Further, the thin copper plate 23 may be made detachable so that the thin copper plate 23 can be attached or detached depending on the result of the heat radiation effect only by the heat sink 20. The reason why the thin copper plate 23 as the heat conductive member is made flexible is to absorb and relieve the load on the heat radiating plate 20 due to the pressure contact, and to prevent the CCD 9 from being stressed. In this embodiment, the heat of the heat radiating plate 20 is released to the light shielding cover 17 side. However, the present invention is not limited to this, and any component of the apparatus main body 1 that can expect a heat radiation effect may be a base or a side plate. No problem. According to such a configuration, even if the amount of heat generated by the CCD 9 increases, the CC
The heat radiation of D9 can be secured.

(Invention of Claim 7) FIG. 7 shows a case where the present invention is applied to the embodiment of FIG. 1 (FIG. 2), and FIG. 8 shows a case where the present invention is applied to the embodiment of FIG. In the embodiments of the first and second aspects of the present invention, the method of attaching the heat radiating plate 20 is based on a holding force or an elastic member in consideration of thermal expansion. However, such a method is vulnerable to disturbances such as vibration and external pressure, and the workability of assembling is not so good, and it takes time. The present invention relates to a method of mounting the heat radiating plate 20. The heat radiating plate 20 is brought into surface contact with the CCD 9 in the same manner as in the first and second embodiments, but is fixed by soldering to the PCB substrate 13. In the heat radiating plate 20 of FIG. 7, both ends of the heat radiating portion 20b (front and rear sides of the paper) pass over the PCB board 13,
A U-shaped bent portion 20d was provided so as to be bent around the back side of the PCB substrate 13. A part of the PCB substrate 13 is in contact with the bent portion 20d on the back side, and the contact portion is provided with a soldering margin portion 13b that stands upright on the circuit. When assembling the CCD substrate 19, first, the heat radiating plate 20 is attached to the PCB substrate 13 at a predetermined position, and the CCD 19 is pressed down so that the surfaces on the CCD 9 side are in close contact with each other. In this state, the heat radiating plate 20 is placed on the soldering margin 13b of the PCB substrate 13 upside down.
Is fixed by soldering. And finally C
The CD 9 is soldered and fixed to the PCB substrate 13 while the back surface of the CD 9 is in close contact with the heat sink 20. As described above, the three members are integrally fixed by soldering. However, the CCD 9 and the heat sink 20
Does not cause a problem due to thermal expansion.

In the embodiment shown in FIG. 7, a U-shaped bent portion 20 d is provided on the heat sink 20, and a soldering portion 13 b is provided on the back side of the PCB substrate 13, and both are fixed by soldering. The shape and the soldering position for soldering and fixing are not limited to those described above.
May be changed flexibly according to the configuration of. For example,
In the example shown in FIG. 8, the legs 20e having the same height as the height of the ventilation space from the heat sink 20 to the socket 22 are attached to the PCB.
They are extended to the board 13 side, and both are soldered and fixed to the soldering margin 13c of the PCB board 13 provided so as to face the leg 20e. Then, the CCD 9 is attached to the socket 22 of the PCB substrate 13 by inserting a pin while the back surface of the CCD 9 is in close contact with the heat sink 20.

[0032]

【The invention's effect】

(Advantage of claim 1) In the image reading apparatus of claim 1, a heat sink is interposed between the light receiving sensor and the circuit board.
The light receiving sensor is soldered and fixed on the circuit board while holding and holding the heat radiating plate so that the back surface of the light receiving sensor and the heat radiating plate abut, or abut via the heat conductive material.
The heat radiation of the light receiving sensor can be efficiently performed with a simple configuration. Therefore, it is possible to easily suppress heat generation of the light receiving sensor and make the temperature gradient uniform without the problem of dust and noise. Further, since stress on the light receiving sensor due to thermal expansion can be eliminated, stable image reading can be always performed. (Effect of Claim 2) In the image reading apparatus according to Claim 2, a heat sink is interposed between the light receiving sensor and the circuit board.
The back surface of the light receiving sensor and the heat sink are attached to each other by elastic mounting means so that the heat sink and the heat sink are in contact with each other, and a ventilation space is provided between the heat sink and the circuit board. Since the light receiving sensor is mounted on the circuit board, the heat radiation of the light receiving sensor is further improved by the heat radiating plate and the ventilation space. Therefore, it is possible to further improve the suppression of heat generation of the light receiving sensor and the uniformity of the temperature gradient. Furthermore, since a problem due to thermal expansion is also taken into consideration, stress on the light receiving sensor can be eliminated. (Effect of Claim 3) In the image reading apparatus of Claim 3, a regulating portion for regulating the displacement of the radiator plate is provided on a part of the radiator plate of Claims 1 and 2, and the regulating portion is provided at a position in the thickness direction of the circuit board. Since the light receiving sensor is mounted on the circuit board while applying the restricting portion, the displacement of the heat radiating plate can be easily and reliably prevented, and the weight of the heat radiating plate to the light receiving sensor can be reduced. Therefore, heat generation of the light receiving sensor can be suppressed and the temperature gradient can be reduced, and stress on the light receiving sensor due to the heat radiating plate can be eliminated. (Effect of Claim 4) In the image reading apparatus of Claim 4, a heat sink is interposed between the light receiving sensor and the circuit board, and the surface of the heat sink facing the light receiving sensor is equal to the rear surface area of the light receiving sensor. Or more than equivalent, and at least a part of the radiator plate extends from the circuit board and extends to the ventilation space in the image reading device, so that heat can be efficiently radiated even in a compact device having no space. Therefore, a large heat radiation effect can be obtained. Therefore, it is possible to further improve the suppression of heat generation of the light receiving sensor and the uniformity of the temperature gradient. (Effect of Claim 5) In the image reading device of the present invention, a ventilation hole for outside air is provided in a part of the image reading device, and a part of the heat radiation plate is extended so as to face the ventilation hole. In addition, the heat radiation effect can be further improved, and at the same time, measures against dust flowing into the device can be taken. (Effect of Claim 6) In the image reading device according to claim 6, a flexible heat conductive member is provided between the extending portion of the heat radiating plate extending from the circuit board and a constituent member constituting the image reading device. Since the interposed portion is in contact with both the extending portion of the heat radiating plate and the constituent members of the image reading apparatus, the heat of the heat radiating plate can be efficiently radiated. Therefore, even if the amount of heat generated by the light receiving sensor becomes large, it is possible to reliably cope with the heat radiation, so that it is possible to always stably suppress the heat generation of the light receiving sensor and make the temperature gradient uniform. (Effect of Claim 7) In the image reading apparatus according to Claim 7, a heat sink is interposed between the light receiving sensor and the circuit board, and the heat sink and the circuit board are soldered and fixed to each other. The board and circuit board are soldered and fixed, and the light-receiving sensor is mounted on the circuit board, so that the heat sink can be easily and securely fixed to the circuit board without using any special parts. It is no longer affected by external pressure. Therefore, stress on the light receiving sensor due to the heat radiating plate can be eliminated, heat generation of the light receiving sensor can be suppressed, and the temperature gradient can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image reading apparatus to which the present invention is applied.

FIG. 2 is a detailed view of the periphery of the lens unit of FIG. 1;

FIG. 3 is a main part configuration diagram for explaining an embodiment of the invention of claim 5;

FIG. 4 is a main part configuration diagram for explaining an embodiment of the invention of claim 2;

FIG. 5 is a main part configuration diagram for explaining an embodiment of the third invention.

FIG. 6 is a main part configuration diagram for explaining an embodiment of the invention of claim 6;

FIG. 7 is a main part configuration diagram for explaining an embodiment of the invention of claim 7;

FIG. 8 is a main part configuration diagram for explaining another embodiment of the invention of claim 7;

FIG. 9 is a diagram illustrating a characteristic example of a dark output voltage of a CCD.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image reading apparatus main body, 2 ... Contact glass, 3 ...
Cooling fan, 4 light source, 5-7 mirror, 8 lens
9: CCD, 10: first traveling body, 11: second traveling body, 1
2 ... Filter, 13 ... PCB board, 14 ... Scanner board, 15 ... Lens holder, 16 ... Lens unit, 17
... light-shielding cover, 18 ... bracket, 19 ... CCD board,
Reference numeral 20: heat sink, 21: ventilation hole, 22: socket, 23:
Thin copper plate.

Claims (7)

[Claims] 1. An image reading apparatus for illuminating a document by illuminating means and projecting a light beam containing information to be read from the document on a light receiving sensor mounted on a circuit board by an image forming element to form an image. A heat sink having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and at least the back surface of the light receiving sensor and the heat sink are in contact with each other via a heat conductive material. The image reading apparatus wherein the light receiving sensor is soldered and fixed on the circuit board while holding and holding the heat sink. 2. An image reading apparatus for illuminating a document by illuminating means and projecting a light beam containing information to be read from the document on a light receiving sensor mounted on a circuit board by an image forming element to form an image. A heat sink having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and at least the back surface of the light receiving sensor and the heat sink are in contact with each other via a heat conductive material. The image reading apparatus according to claim 1, wherein the light receiving sensor is mounted on the circuit board so that a ventilation space is provided between the heat sink and the circuit board. 3. A regulating portion for regulating a displacement of the radiating plate is provided on a part of the radiating plate, and the regulating portion is applied to a portion of the circuit board in a thickness direction, so that the light receiving sensor is mounted on the circuit board. The image reading device according to claim 1, wherein the image reading device is attached to the image reading device. 4. An image reading apparatus which illuminates a document by illuminating means and projects and forms a light beam containing information to be read from the document on a light receiving sensor mounted on a circuit board by an image forming element. A heat radiating plate having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and the surface of the heat radiating plate facing the light receiving sensor is equal to or more than the rear surface range of the light receiving sensor. An image reading device, wherein at least a part of the heat radiating plate extends from the circuit board and extends to a ventilation space in the image reading device. 5. The image reading apparatus according to claim 4, wherein a ventilation hole for outside air is provided in a part of the image reading device, and a part of the heat radiating plate extends so as to face the ventilation hole. Image reader. 6. An image forming apparatus according to claim 6, further comprising: a heat radiation plate extending from the circuit board and a component constituting the image reading device.
6. The image forming apparatus according to claim 1, wherein a heat conductive member having high heat conductivity is interposed therebetween so as to be in contact with both the extending portion of the heat radiating plate and a constituent member of the image reading apparatus. The image reading device according to any one of the above. 7. An image reading apparatus which illuminates a document by illuminating means, and projects and forms a light beam containing information to be read from the document on a light receiving sensor mounted on a circuit board by an image forming element. A heat sink having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit board, and the heat sink and the circuit board can be fixed to each other by soldering, and at least the heat sink and the An image reading apparatus, wherein the light receiving sensor is mounted on the circuit board by soldering and fixing the circuit board.