JP3667022B2 - Image reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus, for example, an image reading apparatus such as an image scanner, a digital copying machine, and a facsimile, and more particularly, to a countermeasure for temperature rise of a light receiving sensor.
[0002]
[Prior art]
In general, in a digital image reading apparatus using a light receiving element such as a CCD, an original is illuminated, reflected light from a predetermined reading line is guided to the CCD by an optical system such as an imaging lens, and is imaged. The image is decomposed into pixels of a predetermined size, and each pixel is photoelectrically converted to form an image signal. By the way, a recent reduction optical system image reading apparatus using a CCD and an imaging lens has a high resolution such as 400 dpi and 600 dpi for an A3 size document, and a reading speed of about 200 mm / s or more. Tend to be faster. In order to achieve both high resolution and high speed, it is necessary to use a CCD with 5000 to 7500 pixels and drive the CCD at a high speed with a driving frequency of several tens of MHz.
[0003]
However, along with this, the amount of self-heating of the CCD also increases, and the temperature gradient of the heat generation temperature also increases, degrading CCD characteristics such as dark current, transfer efficiency, and output level difference of odd and even channels, and reading images This is a cause of quality degradation. Specifically, an increase in dark current greatly affects the image, such as a decrease in S / N, a decrease in transfer efficiency, a decrease in MTF, and an increase in the output level difference of odd and even channels causes a vertical stripe. In particular, the relationship between dark current and CCD temperature is known as a physical phenomenon, and is described in a data sheet or the like for each of various CCDs.
[0004]
FIG. 9 is a diagram showing an example of the dark output characteristics of the CCD as described above. Further, regarding the temperature, an increase in the amount of illumination light for achieving both high resolution and high speed increases the in-machine temperature, which is further added to the CCD temperature. Therefore, in order to perform high-quality image reading, it is one point to use a portion having good CCD characteristics, that is, to use a CCD at the lowest possible temperature state.
[0005]
Various heat dissipation and cooling methods have been devised and filed as countermeasures against the heat of CCDs. For example, the configurations described in JP-A-63-21868, JP-A-4-207256, JP-A-8-102822, etc. are different, but basically the temperature of the CCD is controlled by the fan wind. It is controlled to keep it constant. Other methods include heat dissipation using a holding member as disclosed in Japanese Patent Laid-Open No. 3-27664 and temperature control using a Peltier element as described in the second embodiment of Japanese Patent Laid-Open No. 4-207256.
[0006]
[Problems to be solved by the invention]
However, the fan-based method causes dust to adhere to the optical parts such as the imaging lens and mirror and the surface of the CCD, and causes noise problems. 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, contrary to the mainstream molding (low cost, light weight), In addition, since the holding member and the CCD are fixed, the CCD is distorted and misaligned due to the difference in thermal expansion coefficient between them. The method using a Peltier element is unrealistic at the current cost unit price.
[0007]
The present invention has been made in view of the above circumstances, and in measures against CCD heat,
-To provide an image reading device that solves the problem of differences in thermal expansion coefficient due to dust, noise, and heat dissipation members, and further improves the assembly workability of the sensor substrate including the heat dissipation plate,
-To provide an image reading device with improved CCD heat dissipation effect;
-To provide an image reading device that ensures the mounting of the CCD heat sink and eliminates stress (load) on the CCD,
・ Providing an image reading device that further improves the heat dissipation effect and takes into account the problem of dust,
-To provide an image reading device that can easily and reliably assemble a heat sink and can make a sensor board including the heat sink compact.
Provide an image reading device that is simple and easy to configure, and that can expect a heat dissipation effect without incurring costs,
It was made for the purpose.
[0008]
[Means for Solving the Problems]
  BookThe present invention provides an image reading apparatus in which an original is illuminated by an illuminating means, and a light beam including information to be read from the original is projected and imaged on a light receiving sensor mounted on a circuit board by an imaging element. A heat radiating plate having at least high thermal conductivity is interposed between the back surface of the sensor and the circuit board so that at least the back surface of the light receiving sensor and the heat radiating plate are in contact with each other or through a heat conductive material. The light receiving sensor is soldered and fixed onto the circuit board while holding and holding the heat sink.In addition, a thermal conductive member that is flexible and has high thermal conductivity is interposed between the extending part of the heat radiating plate extending from the circuit board and the constituent members constituting the image reading device, Make contact with both the extension of the heat sink and the components of the image reader.It is characterized by that.
[0009]
  According to a second aspect of the present invention, there is provided an image reading apparatus for illuminating an original with an illuminating means and projecting and imaging a light beam containing information to be read from the original on a light receiving sensor mounted on a circuit board by an imaging element. In this case, 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 and the heat radiating plate are in contact with each other, or through a heat conductive material. 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.In addition, a thermal conductive member that is flexible and has high thermal conductivity is interposed between the extending part of the heat radiating plate extending from the circuit board and the constituent members constituting the image reading device, Make contact with both the extension of the heat sink and the components of the image reader.It is characterized by that.
[0010]
According to a third aspect of the present invention, in the first or second aspect of the present invention, a restricting portion for restricting a deviation of the heat sink is provided in a part of the heat sink, and the restricting portion is applied to a portion in the thickness direction of the circuit board. The light receiving sensor is mounted on the circuit board while being attached.
[0011]
  According to a fourth aspect of the present invention, there is provided an image reading apparatus for illuminating a document with illumination means and projecting and imaging a light beam including information to be read from the document on a light receiving sensor mounted on a circuit board by an imaging element. In addition, 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 surface facing the light receiving sensor in the heat sink is equal to the back surface range of the light receiving sensor or At least a part of the heat sink extends from the circuit board and extends to the ventilation space in the image reader.And, between the extension part of the heat radiating plate extending from the circuit board and the constituent members constituting the image reading apparatus, a heat conductive member that is flexible and has high thermal conductivity is interposed, The heat sink is in contact with both the extending portion of the heat sink and the component of the image reading device.It is characterized by that.
[0012]
According to a fifth aspect of the present invention, in the invention of the fourth aspect, an outside air ventilation hole 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. It is a feature.
[0014]
  Claim6In the image reading apparatus of the present invention, the original is illuminated by an illuminating means, and a light beam including information to be read from the original is projected and imaged onto a light receiving sensor mounted on a circuit board by an imaging element. A heat dissipating plate having at least high thermal conductivity is interposed between the back surface of the light receiving sensor and the circuit substrate, and the heat dissipating plate and the circuit substrate can be soldered and fixed to each other. At least the heat dissipating plate and the circuit Soldering and fixing the board, the light receiving sensor is mounted on the circuit boardIn addition, a thermal conductive member that is flexible and has high thermal conductivity is interposed between the extending part of the heat radiating plate extending from the circuit board and the constituent members constituting the image reading device, Make contact with both the extension of the heat sink and the components of the image reader.It is characterized by that.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
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, after a document (not shown) is placed on a contact glass 2 serving as a document table, the document is illuminated by a light source 4 positioned below the document, and then the reflected light is reflected on the first mirror 5, The light is sequentially folded by the second mirror 6 and the third mirror 7, then passes through a filter 12 for color correction or the like, and is condensed by the lens 8 and projected onto the CCD 9. 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 a second traveling body 11. As an actual reading operation, the first traveling body 10 and the second traveling body 11 connected to the driving means (not shown) are moved in the arrow (sub-scan) direction in the figure at a speed ratio of 1: 1/2. At the same time, reading scanning is performed two-dimensionally by scanning the CCD 9 in the main scanning direction. The PCB board 13 is a circuit board that outputs driving and reading signals for the CCD 9, and the CCD 9 is attached to the PCB board 13. The scanner board 14 installed in the rear part processes the signal from the PCB board 13 and transfers it to the IPU (image processing unit), or controls the rotational speed of the motor of the traveling body drive source in accordance with the variable magnification. It is a circuit board which performs. Further, the filter 12, the lens 8, the CCD 9, and the like are integrally mounted on the lens holder 15 and constitute a lens unit 16. The lens unit 16 and the scanner substrate 14 are covered with a light-shielding cover 17 to prevent intrusion of disturbance (flare light, dust, etc.). Reference numeral 3 denotes a cooling fan that prevents the temperature inside the apparatus from rising due to the illumination light of the light source 4, and outside air that has passed through the dust-proof means is taken into the apparatus.
[0016]
  FIG. 2 is a configuration diagram of a main part of an image reading apparatus to which the present invention is applied.Figure 2,Details of the periphery of the lens unit 16 shown in FIG.IndicateAs shown in the figure, a CCD 9 is mounted on a PCB substrate 13 to form a CCD substrate 19. The CCD substrate 19 is fixedly supported by a screw or the like (not shown) on the back side of a bracket 18 formed in a substantially U shape when viewed from the side. The bracket 18 is for adjusting the optical position of the CCD 9 to an ideal position, and a part of the rear portion of the lens holder 15 enters the U-shaped shape of the bracket 18. A position adjusting mechanism for the CCD 9 is provided between the bracket 18 and the lens holder 15.
[0017]
In FIG. 2, the position adjustment mechanism is omitted for the sake of clarity, but actually, an adjustment mechanism is provided in directions as required, such as main, sub-scanning, optical axis direction, and rotation direction. Here, in the present invention, a heat radiating plate is used as a heat countermeasure for the CCD 9, but the heat radiating plate can be provided without the difference in thermal expansion coefficient and stress on the CCD 9, which was a conventional problem. That is, in the present invention, as shown in FIG. 2, the heat radiating plate 20 is interposed between the CCD 9 and the PCB substrate 13 constituting the CCD substrate 19, and the back surface of the CCD 9 and the PCB substrate 13 are respectively formed on both surfaces of the heat radiating plate 20. The heat sink 20 is pressed from both sides of the CCD 9 and the PCB substrate 13 and the CCD 9 is directly fixed to the PCB substrate 13 by soldering. The case of the CCD 9 is usually composed of ceramics and a cover glass, but the ceramic part, particularly the back surface having the widest area, is the most efficient and effective part for absorbing heat from the CCD 9.
[0018]
Therefore, it is desirable that the surface of the heat radiating plate 20 in contact with the back surface of the CCD 9 is larger in area (at least equivalent) than the back surface of the CCD 9, and more heat dissipation effect can be expected. The CCD 9 is completely fixed to the PCB substrate 13 by soldering, but the heat radiating plate 20 is held only by the clamping force sandwiched between the CCD 9 and the PCB substrate 13. The heat radiating plate 20 is made of high heat conductive aluminum or copper-based material, but has a large coefficient of thermal expansion. Conventionally, this has been a problem, but as described above, in the present invention, the CCD 9 and the heat radiating plate 20 are not fixed but are brought into press contact, so that the heat radiating plate 20 expands due to the temperature rise of the CCD 9. However, the CCD 9 is not affected.
[0019]
In the case where higher heat dissipation efficiency is required, thermal conductivity that does not cause the CCD 9 and the heat sink 20 to be fixed, such as silicone oil, silicone rubber, polyimide film, or flexible heat conductive tape, between the CCD 9 and the heat sink 20. The back surface of the CCD 9 and the heat radiating plate 20 are completely brought into close contact with each other through the material. In addition, in the contact surface between the heat sink 20 and the PCB substrate 13, there is no problem if the circuit wiring arranged on the PCB substrate 13 is not electrically connected by contact with the heat sink 20. Insulation measures such as interposing an insulating member such as phenol resin between the heat sink 20 and the PCB substrate 13 or applying an insulation treatment to the surface of the heat sink 20 are required. Since the heat sink 20 is sandwiched and installed simultaneously with the soldering of the CCD 9 to the PCB substrate 13 as described above, the three components can be integrated and handled as the CCD substrate 19 with the heat sink 20 without conventional problems. .
[0020]
Whatever the shape of the heat sink 20 is, the CCD 9 is effective in suppressing the heat generation temperature to some extent and making the temperature gradient uniform only by attaching the heat sink. For example, only the vertical portion 20 a in which the heat sink 20 is sandwiched between the CCD 9 and the PCB substrate 13 may be used. However, since one side is almost in close contact with the PCB substrate 13, the heat dissipation function is hindered, the efficiency is low, and a great effect cannot be expected. There is no problem as long as the surface area of the vertical portion 20a can be increased as much as possible, but there is a limit to the space of the apparatus, and an apparatus that tends to be compact has almost no extra space. Therefore, it is practically difficult to simply enlarge the vertical portion 20a.
[0021]
  there, ReleaseEven in a device that has no extra space available for heat, the heat dissipation efficiency is prevented from being lowered by the PCB substrate 13 and the like, 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, the upper part of the vertical portion 20 a is extended from the PCB substrate 13, and the space between the upper part of the PCB substrate 13 and the light shielding cover 17. The heat dissipation part 20b was provided by bending at The heat radiating portion 20 b extends in a direction (sub-scanning direction) parallel to the moving direction of the traveling body, and protrudes into a space along the light shielding cover 17. The space space is a ventilation space for radiating heat of the scanner substrate 14 (FIG. 1), and by exposing the heat radiating portion 20b to the air in the space, the heat radiation is applied smoothly and further promoted.Above,Although the heat radiating portion 20b has been described with the L-shaped heat radiating plate 20 extending in the sub-scanning direction, the shape of the heat radiating plate 20 is not limited, and in any shape according to the space of the deviceAlso suitableNeedless to say, if the surface area of the heat dissipating part 20b is increased as much as possible, the effect is increased.
[0022]
  ThroughUsually, a vent hole 21 for releasing the heat to the outside is provided near a circuit board on which a heat generating IC such as the scanner board 14 is loaded (in FIG. 3, it is opened on the right side plate of the main body 1). ) The heat from the heat radiating portion 20b in the heat radiating ventilation space of the scanner substrate 14 is also released outside through the ventilation holes 21. Therefore, if the heat radiation part 20b can be installed at a position as close as possible to the ventilation hole 21, the heat radiation effect is further improved. In addition, if a cooling fan is provided in the ventilation hole 21, the effect becomes remarkable. However, releasing heat to the outside means putting outside air into the device, so no matter how much dust-proofing measures are taken, there is a problem with dust.ButEssentialZThe problem becomes more apparent when a cooling fan is used.
[0023]
  there, ReleaseIncreased thermal effect and reduced dust problems. For example, as shown in FIG. 3, the shape of the heat sink 20 is a U-shape when viewed from the side, and another bent portion is provided at the right end of the heat sink 20b of the heat sink 20 shown in FIG. Also extended the heat dissipating part 20b '. The surface of the heat radiating portion 20 b ′ extending downward is opposed to the ventilation hole 21. Moreover, the clearance gap between the light shielding cover 17 and the upper part of the heat radiating part 20b was also made small. Then, air (wind) flowing in the direction of the CCD 9 becomes small, dust can be suppressed as much as possible, and heat radiation can be efficiently performed from the vent hole 21 together with heat radiation of the scanner substrate 14 by the heat radiation portion 20b 'extended downward. . This is even more true if air is directly applied to the heat dissipating part 20b 'extending downward using a cooling fan. Although there is a concern about the dust problem, the wind from the cooling fan hits the heat dissipating part 20b 'extending downward and is blocked so that the inflow of dust into the CCD 9 is not a problem. In order to further improve the heat radiation effect including the scanner substrate 14, a dedicated ventilation hole for the CCD 9 is provided in addition to the ventilation hole 21, and the heat radiation extends downward immediately before and opposite the ventilation hole. The portion 20b 'may be positioned. Further, if a cooling fan is provided, the dustproof effect is the same and the heat dissipation effect is further improved.
[0024]
  Figure4 isOther image forming apparatuses to which the present invention is appliedIn the main part configuration diagram, the heat sink 20AsUse the L-shaped one shown in FIG.,thisAlthough the heat sink 20 is interposed between the CCD 9 and the PCB substrate 13, FIG.ExampleIn this way, the CCD 9 and the PCB substrate 13 are not sandwiched, and the heat radiating plate 20 is in contact with only the back surface of the CCD 9 and is not in contact with the PCB substrate 13 apart. That is, the heat radiating plate 20 is attached only to the CCD 9. Although the attachment method has been described with reference to FIG. 2, it is performed using a leaf spring or a flexible heat conductive tape as an elastic member in consideration of thermal expansion. Pins are inserted and attached to the CCD 9 with the heat sink 20 and the socket 9 for the CCD 9 provided on the PCB substrate 13. Then, the heat sink 20 and the PCP board 13 are separated by the height of the socket 22 and a space is formed between them. Since the space can be used as a ventilation space, further improvement in heat dissipation efficiency can be expected. The means for separating the heat dissipation 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, and for example, a space is used between the PCB substrate 13 and the heat dissipation plate 20 using a spacer or the like. And a method of directly soldering and fixing the CCD 9 to the PCB substrate 13 may be used..
[0025]
  ExampleFor example, as shown in FIG.ExampleThen, the heat radiating plate 20 is held only by the clamping force by soldering between the CCD 9 and the PCB substrate 13. However, when vibration of a force larger than the holding force or an unexpected external pressure is applied to the heat radiating plate 20, The heat radiating plate 20 easily moves (especially the amount of deviation downward increases). When the amount of deviation increases, the worst case is that the heat sink 20 contacts the pins of the CCD 9 and causes an electrical short to destroy the CCD 9. Also shown in FIG.ExampleSince the heat sink 20 is attached only to the CCD 9, the optical position of the CCD 9 is shifted even if the heat sink 20 is touched a little. Furthermore, since all the weight of the heat sink 20 is applied to the pins of the CCD 9 and the direction of the application is also in the direction of falling to the CCD 9 side, problems such as deformation of the pins of the CCD 9 and disconnection from the socket 22 occur. there, ReleaseThe occurrence of the above problem is prevented by regulating the displacement of the hot plate 20 and reducing the weight load on the CCD 9.
[0026]
  FIG.Other image forming apparatus to which the present invention is appliedThe main part configuration diagram of the present invention, LStopper portions 20c, which are partially bent to the PCB substrate 13 side, are provided at both ends (front and back of the paper) of the heat radiating portion 20b provided on the upper portion of the letter-shaped heat radiating plate 20. When the heat sink 20 is sandwiched and held between the CCD 9 and the PCB substrate 13, the stopper portion 20 c comes into contact with the portion 13 a in the thickness direction of the upper portion of the PCB substrate 13, so that the heat sink 20 has a downward direction and a rotational direction ( The movement around the optical axis is restricted, and the displacement of the CCD 9 is prevented.
[0027]
  Further, since the heat sink 20 is placed on the PCB substrate 13 by the stopper portion 20c, all the weight of the heat sink 20 is applied to the PCB substrate 13. Therefore, the CCD 9 is not subjected to any stress. Even if the weight of the heat sink 20 is applied to the PCB substrate 13, the PCB substrate 13 is not bent and deformed because it is applied in a direction strong against the load. By devising the shape and position of the stopper portion 20c provided on the heat radiating plate 20, it is possible to prevent not only the downward and rotational displacements but also the upward and lateral displacements. The deviation regulation and weight reduction means for the CCD 9 are shown in the figure.ExampleThe configuration and method are not limited as long as the PCB substrate 13 and the heat dissipation plate 20 are used. For example, onExampleThe same results are obtained even if the heat radiating portion 20b (bent portion thereof) is directly brought into contact with the portion 13a in the thickness direction of the PCB substrate 13 instead of providing the stopper portion 20c as described in the above in the heat radiating plate 20. Is obtained. Also shown in FIG.ExampleIn this case, for example, a portion having the same shape as the stopper portion 20 c may be provided on the heat radiating plate 20 and extended until the stopper portion 20 c comes into contact with the PCB substrate 13.
[0028]
  In the above explanation,Heat dissipation plate 20 as countermeasure against heat generation and temperature gradient of CCD 9The, Shown in FIG.ExampleAs described above, the heat can be efficiently dissipated even in a device having no space by dividing the portion (vertical portion 20a) that absorbs and transmits the heat of the CCD 9 and the portion that releases the absorbed heat (heat dissipating portion 20b). I did it. However, the heat dissipating part 20b alone is not sufficient as a heat generation countermeasure associated with the high-speed driving of the CCD 9 that is expected in the future, and the heat dissipating plate 20 itself may become a heat generating element because it cannot dissipate heat. Nevertheless, there is a limit even if the heat radiation part 20b is enlarged. Therefore, in the present invention, even if a heat quantity equal to or greater than the heat dissipation capacity enters the heat dissipation plate 20, the heat is absorbed by the apparatus main body 1 side through the flexible heat conductive member.
[0029]
  FIG.BookinventionForming apparatus to which is appliedThe principal part block diagram for demonstrating one Example is shown, The example using the thin copper plate 23 as a flexible heat conductive member is shown as an example. The thin copper plate 23 has a central portion fixed to the upper portion of the heat radiating portion 20 b, and both end portions are provided in contact with the back side of the light shielding cover 17. At this time, the thin copper plate 23 comes into contact with the light-shielding cover 17 in a wide range and in a pressed state so that heat transfer is performed efficiently and smoothly. Needless to say, the thin copper plate 23 may be fixed on the light shielding cover 17 side. Alternatively, the thin copper plate 23 may be detachable so that the thin copper plate 23 can be attached or removed depending on the result of the heat dissipation effect of the heat sink 20 alone. The reason why the thin copper plate 23 which is a heat conductive member is made flexible is to absorb and relieve the load applied to the heat radiating plate 20 due to the pressing contact so as not to apply stress to the CCD 9. 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 member of the apparatus main body 1 that can expect a heat radiating effect is a base or a side plate. It doesn't matter. According to such a configuration, even if the amount of heat generated by the CCD 9 increases, the heat dissipation of the CCD 9 can be reliably ensured.
[0030]
  Figure7 isExample shown in FIG.In addition, FIG.Example shown in FIG.The present invention is adapted toThe example shown in FIG. 2 or the example shown in FIG.The mounting method of the heat radiating plate 20 is based on a pinching 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 assembling workability is not so good and takes time.there,What is the heat sink 20 with the CCD 9?Examples shown in FIGS. 2 and 4In the same manner as above, the surface contact is made, but the PCB substrate 13 is fixed by soldering. In the heat radiating plate 20 of FIG. 7, U-shaped bent portions 20d that are bent so as to pass over the PCB substrate 13 and wrap around the back side of the PCB substrate 13 are provided at both ends of the heat radiating portion 20b. It was. A part of the PCB substrate 13 is in contact with the bent portion 20d on the back side, and a soldering margin portion 13b that is erected on the circuit is provided at the contact portion. In assembling the CCD substrate 19, first, the heat sink 20 is attached to the PCB substrate 13 at a predetermined position, and the CCD 9 side surfaces are pressed against each other so that the surfaces are in close contact with each other. In this state, the bent portion 20d of the heat sink 20 is soldered and fixed to the soldering portion 13b of the PCB substrate 13 turned over. Finally, the CCD 9 is soldered and fixed to the PCB substrate 13 while the back surface is in close contact with the heat sink 20. As described above, the three members are integrally fixed by soldering. However, since the CCD 9 and the heat radiating plate 20 are in surface contact, there is no problem due to thermal expansion.
[0031]
  Shown in FIG.ExampleThen, the U-shaped bent portion 20d is provided on the heat radiating plate 20, and the soldering portion 13b is provided on the back side of the PCB substrate 13 to fix them together. However, the present invention is not limited to this. The shape for fixing, the soldering position, and the like may be changed flexibly depending on the configuration of the CCD substrate 19. For example, in the example shown in FIG. 8, the PCB substrate 13 provided so that the legs 20e having the same height as the ventilation space by the socket 22 from the heat sink 20 are extended to the PCB substrate 13 side and opposed to the legs 20e. Both are fixed by soldering with the soldering margin 13c. Then, the CCD 9 is attached by inserting pins into the socket 22 of the PCB substrate 13 while keeping the back surface of the CCD 9 in close contact.
[0032]
【The invention's effect】
  (Effect of Claim 1)
  In the image reading apparatus according to claim 1, a heat radiating plate is interposed between the light receiving sensor and the circuit board so that the back surface of the light receiving sensor and the heat radiating plate are in contact with each other or through a heat conductive material. Since the light receiving sensor is soldered and fixed on the circuit board while holding and holding the heat radiating plate, heat radiation of the light receiving sensor can be performed efficiently with a simple configuration. Therefore, it is possible to easily suppress the heat generation of the light receiving sensor and make the temperature gradient uniform without problems of dust and noise. Furthermore, since it is possible to eliminate stress on the light receiving sensor due to thermal expansion, stable image reading can always be performed.
  Further, a flexible heat conductive member is interposed between the extending portion of the heat sink extending from the circuit board and the constituent members constituting the image reading device, and the extending portion of the heat sink and the image reading device Since both components are in contact with each other, the heat of the heat radiating plate can be efficiently radiated. Therefore, heat can be reliably dealt with no matter how much the amount of heat generated by the light receiving sensor increases, so that stable heat generation suppression of the light receiving sensor and uniform temperature gradient can be achieved.
  (Effect of claim 2)
  In the image reading apparatus according to claim 2, a heat radiating plate is interposed between the light receiving sensor and the circuit board so that the back surface of the light receiving sensor and the heat radiating plate come into contact with each other or through a heat conductive material. The light receiving sensor is mounted on the circuit board so that there is a ventilation space between the heat sink and the circuit board, and the heat radiation of the light receiving sensor is more efficient due to the heat sink and the ventilation space. Is up. Accordingly, it is possible to further improve the suppression of heat generation of the light receiving sensor and the uniform temperature gradient. Furthermore, since the problem due to thermal expansion is taken into consideration, stress on the light receiving sensor can be eliminated.
  Further, a flexible heat conductive member is interposed between the extending portion of the heat sink extending from the circuit board and the constituent members constituting the image reading device, and the extending portion of the heat sink and the image reading device Since both components are in contact with each other, the heat of the heat radiating plate can be efficiently radiated. Therefore, heat can be reliably dealt with no matter how much the amount of heat generated by the light receiving sensor increases, so that stable heat generation suppression of the light receiving sensor and uniform temperature gradient can be achieved.
  (Effect of claim 3)
  In the image reading apparatus of claim 3, a restriction part for restricting the displacement of the heat sink is provided on a part of the heat sink of claims 1 and 2, while applying the restriction part to a portion in the thickness direction of the circuit board, Since the light receiving sensor is mounted on the circuit board, it is possible to easily and reliably prevent the heat sink from shifting, and to reduce the weight of the heat sink to the light receiving sensor. Therefore, it is possible to suppress the heat generation and temperature gradient of the light receiving sensor, and to eliminate stress on the light receiving sensor due to the heat sink.
  (Effect of claim 4)
  In the image reading device according to claim 4, a heat sink is interposed between the light receiving sensor and the circuit board, and a surface of the heat sink facing the light receiving sensor is equal to or greater than a back surface range of the light receiving sensor, and at least A part of the heat sink extends from the circuit board and extends to the ventilation space in the image reader, so heat can be efficiently dissipated even in a compact device with no space. Can be obtained. Accordingly, it is possible to further improve the suppression of heat generation of the light receiving sensor and the uniform temperature gradient.
  Further, a flexible heat conductive member is interposed between the extending portion of the heat sink extending from the circuit board and the constituent members constituting the image reading device, and the extending portion of the heat sink and the image reading device Since both components are in contact with each other, the heat of the heat radiating plate can be efficiently radiated. Therefore, heat can be reliably dealt with no matter how much the amount of heat generated by the light receiving sensor increases, so that stable heat generation suppression of the light receiving sensor and uniform temperature gradient can be achieved.
  (Effect of Claim 5)
  In the image reading device of claim 5,Claim 4A part of the image reader is provided with a vent hole for outside air, and a part of the heat sink is extended so as to face the vent hole, so that the heat dissipation effect can be further improved, and at the same time it flows into the apparatus. Can also take measures against dust.
  (Claim6Effect)
  Claim6In this image reading apparatus, a heat sink is interposed between the light receiving sensor and the circuit board, and the heat sink and the circuit board can be fixed to each other by soldering. At least the heat sink and the circuit board are fixed by soldering. Since the light receiving sensor is mounted on the circuit board, the heat radiating plate can be fixed to the circuit board easily and reliably without using special parts, and is not affected by vibration or external pressure. Therefore, it is possible to eliminate stress on the light receiving sensor due to the heat radiating plate, to suppress heat generation of the light receiving sensor, and to equalize the temperature gradient.
  Further, a flexible heat conductive member is interposed between the extending portion of the heat radiating plate extending from the circuit board and the constituent members constituting the image reading device, and the extending portion of the heat radiating plate and the image reading device are arranged. Therefore, the heat of the heat radiating plate can be radiated efficiently. Therefore, heat can be reliably dealt with no matter how much the amount of heat generated by the light receiving sensor increases, so that stable heat generation suppression of the light receiving sensor and uniform temperature gradient can be achieved.
[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.
[Fig. 3]Example of heat sinkIt is a principal part block diagram for demonstrating.
[Fig. 4]1 shows an example of an image reading apparatus to which the present invention is applied.It is a principal part block diagram.
FIG. 5 is a main part configuration diagram showing another example of an image reading apparatus to which the present invention is applied;
[Fig. 6]An image reading apparatus to which the present invention is appliedIt is a principal part block diagram for demonstrating an Example.
[Fig. 7]Other image reading apparatus to which the present invention is appliedIt is a principal part block diagram for demonstrating an Example.
[Fig. 8]Further of the image reading apparatus to which the present invention is appliedIt is a principal part block diagram for demonstrating another Example.
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 ... 1st traveling body, 11 ... 2nd traveling body, 12 DESCRIPTION OF SYMBOLS ... Filter, 13 ... PCB board, 14 ... Scanner board, 15 ... Lens holder, 16 ... Lens unit, 17 ... Shading cover, 18 ... Bracket, 19 ... CCD board, 20 ... Heat sink, 21 ... Ventilation hole, 22 ... Socket 23 ... A thin copper plate.

Claims (6)

In an image reading apparatus for illuminating a document with illumination means and projecting and forming a light beam including information to be read from the document on a light receiving sensor mounted on a circuit board by an imaging element, the back surface of the light receiving sensor And a heat radiating plate having at least a high thermal conductivity between the circuit board and the heat radiating plate so that at least the back surface of the light receiving sensor and the heat radiating plate are in contact with each other or through a heat conductive material. The light receiving sensor is soldered and fixed onto the circuit board by sandwiching and holding , and flexible between the extension part of the heat sink extending from the circuit board and the constituent members constituting the image reading device An image reading apparatus characterized in that a heat conductive member having high heat conductivity is interposed so as to be in contact with both the extending portion of the heat radiating plate and the constituent members of the image reading apparatus. In an image reading apparatus for illuminating a document with illumination means and projecting and forming a light beam including information to be read from the document on a light receiving sensor mounted on a circuit board by an imaging element, the back surface of the light receiving sensor And a heat dissipation plate having at least high thermal conductivity between the circuit board and the circuit board, and at least the back surface of the light receiving sensor and the heat dissipation plate are in contact with each other or are in contact with each other via a heat conductive material. 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 extending portion of the heat radiating plate extends from the circuit board. And a heat conductive member having a high thermal conductivity is interposed between the heat sink and the component members constituting the image reading device. Image reading apparatus characterized by being in contact with both the forming member.   A restricting portion for restricting the displacement of the heat sink is provided in a part of the heat sink, the restricting portion is applied to a portion in the thickness direction of the circuit board, and the light receiving sensor is mounted on the circuit board. The image reading device according to claim 1, wherein the image reading device is an image reader. In an image reading apparatus for illuminating a document with illumination means and projecting and forming a light beam including information to be read from the document on a light receiving sensor mounted on a circuit board by an imaging element, the back surface of the light receiving sensor And a heat sink having at least high thermal conductivity between the circuit board and the surface of the heat sink facing the light receiving sensor is equal to or greater than or equal to the back surface range of the light receiving sensor, and at least A part of the heat radiating plate extends from the circuit board , extends to a ventilation space in the image reading apparatus, and an extending portion of the heat radiating plate extending from the circuit board and a component constituting the image reading apparatus; between, especially that it has to flexibly and is interposed a thermally conductive member having a high thermal conductivity, in contact with both of the components of the heat radiating plate extending portion and the image reading apparatus Image reading apparatus according to.   The image reading apparatus according to claim 4, wherein a part of the image reading apparatus is provided with a vent hole for outside air, and a part of the heat radiating plate extends so as to face the ventilation hole. In an image reading apparatus for illuminating a document with illumination means and projecting and forming a light beam including information to be read from the document on a light receiving sensor mounted on a circuit board by an imaging element, the back surface of the light receiving sensor And a circuit board having at least a high thermal conductivity between the heat sink and the circuit board, the heat sink and the circuit board can be soldered to each other, and at least the heat sink and the circuit board are soldered. The light receiving sensor is mounted on the circuit board , and is flexible and has high heat between the extending part of the heat sink extending from the circuit board and the constituent members constituting the image reading device. An image reading apparatus characterized in that a thermally conductive member having conductivity is interposed so as to be in contact with both the extending portion of the heat radiating plate and the constituent members of the image reading apparatus.

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