JP2006197012A - Image reading apparatus and image forming apparatus using the same - Google Patents

Abstract

In an image reading apparatus mounted on a digital copying machine or a facsimile apparatus, the drive frequency of the CCD is increased and the sensitivity is improved. As a result, the heat generation of the CCD image sensor becomes a problem. Although a method for suppressing heat generation is proposed by changing the CCD drive condition according to the situation, it cannot cope with heat generation in the case of continuous CCD drive. Although a configuration in which a heat sink is sandwiched between the CCD and the CCD substrate has been proposed, there is a problem in cooling the heat sink itself.
A part of a heat conductor is in contact with a side surface of a CCD mounted on a CCD substrate. The other part 23 b of the heat conductor 23 is fixed in contact with the scanner housing 22. Heat generated in the CCD is transmitted to the scanner housing 22 by the heat conductor 23.
[Selection] Figure 2

Description

  The present invention relates to a technique for suppressing a temperature rise of a CCD image sensor in an image reading apparatus using the CCD image sensor.

An image reading apparatus mounted on a digital copying machine or a facsimile apparatus reads an image by irradiating light on a manuscript with a light source and converting reflected light from the manuscript into an electrical signal with a CCD image sensor.
In recent years, CCD drive frequency has been increased and sensitivity has been improved for the purpose of improving reading speed. As a result, heat generation of the CCD image sensor has become a problem.
A large number of optical parts such as a CCD, a mirror, a lens, and the like are mounted inside the scanner casing, and it is difficult to perform normal reading because dust or dust adheres to these parts. Therefore, if outside air is introduced by a fan to cool the CCD, there is a risk of dust adhesion, and it is necessary to install an expensive electrostatic filter, which increases costs, and maintenance such as periodic cleaning is also required. Because it is necessary, it will put a burden on customers.
As a method for suppressing the temperature rise of the CCD, for example, a solution has been invented by changing the drive frequency of the CCD in the reading standby state and the reading state (see, for example, Patent Document 1). According to the present invention, the circuit configuration is complicated for switching the drive pulse of the CCD, and time for switching is required. Furthermore, there is a problem that the temperature changes every time the drive pulse is changed, which affects the read data.
In addition, a method of suppressing temperature rise by controlling power supply to the CCD has been invented (see, for example, Patent Document 2). This method also requires power supply switching means, complicates the circuit configuration, and cannot cope with the temperature rise during continuous reading.

There is a proposal to attach a light emitting member in close contact with a resin casing surrounded by a heat sink, connect a ground ground from the light emitting member to a heat sink via a ground ground layer, and dissipate heat by this ground ground layer ( For example, see Patent Document 3.) In this method, since the cross-sectional area of the ground earth layer is not so large and the thermal resistance is large, sufficient heat dissipation cannot be expected.
A method has been proposed in which heat is released from the heat dissipation plate by attaching a heat dissipation plate between the CCD and the PCB substrate (see, for example, Patent Document 4). In the embodiment shown here, since the heat sink is in direct contact with the CCD, heat conduction to the heat sink is improved, but the heat sink itself is not in direct contact with the housing, so the heat of the heat sink is Only by diffusing inside the casing, the cooling action of the heat sink is weakened as the temperature inside the casing rises. In another embodiment, the heat radiating plate is cooled by exposing a part of the heat radiating plate to the cooling air or contacting the housing or the cover via another heat conductive member. However, since the cooling air is passed through the inside of the apparatus, the above-mentioned dust problem cannot be solved. Moreover, since the method of passing through the heat conducting member indirectly cools the heat sink, the cooling effect is not so great.

Japanese Patent Laid-Open No. 06-268821 Japanese Patent Laid-Open No. 06-141132 Japanese Patent Application Laid-Open No. 06-253093 JP-A-10-210221

  The present invention is an invention for solving such a problem, and provides a CCD heat radiation means having a very wide application range because it has a simple structure, has a large heat radiation effect, and can be variously modified. With the goal.

According to the first aspect of the present invention, in a digital image reading apparatus that scans a document and converts optical information of an image into an electrical signal using a CCD image sensor, a thermal conductor is provided in a casing of the CCD image sensor. A part of the heat conductor is brought into contact with the other part, and another part of the heat conductor is brought into contact with the inside of the scanner housing.
According to a second aspect of the present invention, in the image reading apparatus according to the first aspect of the present invention, the image reading apparatus further includes a cooling unit that cools the vicinity of a part of the thermal conductor of the scanner casing that is in contact with the scanner casing.

According to a third aspect of the present invention, in the image reading apparatus according to the second aspect, the cooling means is a heat radiating member attached to the outside of the scanner housing.
According to a fourth aspect of the present invention, in the image reading apparatus according to the second aspect, the cooling means is a cooling fan attached to the outside of the scanner casing.

According to a fifth aspect of the present invention, in the image reading apparatus according to the third aspect, the cooling means includes a cooling fan for cooling the heat radiating member.
According to a sixth aspect of the invention, there is provided an image forming apparatus using the image reading device according to any one of the first to fifth aspects.

  In the present invention, a part of the heat radiating body is brought into contact with the side surface of the CCD and the other part is brought into contact with the scanner housing. Further, since forced cooling using a cooling fan can be performed, the amount of heat generated by the CCD can be efficiently dissipated.

FIG. 1 is a diagram showing an overall layout of the configuration of an image reading apparatus to which the present invention is applied.
In the figure, reference numeral 1 is a lamp, 2 is a first mirror, 3 is a first carriage, 4 is a second mirror, 5 is a third mirror, 6 is a second carriage, 7 is a white reference plate, 8 is an original scale, 9 Is a contact glass, 10 is a document cover, 11 is a drive motor, 12 is a drive transmission belt, 13 is a drive wire pulley, 14 is a drive wire, 15 is a driven pulley, 16 and 17 are shaft-driven driven pulleys, 18 is a wire tension spring, Reference numeral 19 denotes a lens block, 20 denotes a CCD, 21 denotes a CCD substrate, and 22 denotes a scanner housing.
The original is irradiated with the lamp 1, and the image information is turned back by the first mirror 2, the second mirror 4, and the third mirror 5 and input to the CCD 20 through the lens in the lens block 19 fixed to the main body.
The first mirror 2 forms the first carriage 3 together with the lamp 1, and the second mirror 4 and the third mirror 5 form the second carriage 6 together with the driven pulley 15. The carriages are respectively locked by the drive wires 14, and when the white reference plate 7 and the book document are read, the first carriage 3 and the second carriage 6 can be read. A load is applied to the drive wire 14 by a wire tension spring 18, and the drive motor 11 operates through a drive transmission belt 12 and a drive (wire) pulley 13.

FIG. 2 is a diagram for explaining an embodiment of the present invention.
In the figure, reference numeral 23 denotes a heat conductor, 28 denotes a connecting member, and 29 denotes an adhesive.
The CCD 20 attached to the CCD substrate 21 is attached to the lens block 19 with an adhesive 29 via a plurality of resin connection members 28.
The CCD 20 that converts image information into electrical signals generates heat when driven. Conventionally, natural heat dissipation was supported, but recently, due to high image quality and high speed (clock up) of the scanner image, the ambient temperature of the CCD 20 or the temperature of the CCD 20 itself has risen too much, resulting in performance degradation (image quality, durability). Etc.).
As a normal cooling method, it is conceivable to provide a fan or the like inside the scanner. However, in that case, dust and dirt inside the housing, and dust from the outside are sucked in, causing side effects such as streak images. As a result, regular cleaning is required and often causes complaints from users. Therefore, the heat conductor 23 is brought into contact with the housing of the CCD 20 itself, and the heat generated from the CCD is brought into contact with the inside of the scanner housing 22 so that the heat can be efficiently radiated from the inside of the scanner housing to the outside. Since the scanner housing 22 has a large area exposed to the outside, it has a very large heat capacity and can sufficiently dissipate heat even by natural cooling. In the figure, the contact portion of the thermal conductor 23 with respect to the CCD 20 is shown to be on the side surface of the CCD housing. ) May be contacted. In short, it is important to make the contact area as wide as possible. Note that the contact points between the connecting member 28 and the CCD 20 are discrete and because the connecting member 28 itself is made of a resin having low thermal conductivity, the heat conduction to the lens block 19 is not so large.
This method always dissipates heat regardless of the reading timing, and heat generated by continuous reading can be efficiently transmitted to the housing, so that the temperature rise of the CCD can be suppressed.

FIG. 3 is a diagram for explaining another embodiment of the present invention.
In the figure, reference numeral 24 denotes a heat radiating member.
An example in which heat dissipating means is further provided outside the scanner housing 22 is shown. In the figure, a further heat dissipation effect can be obtained by attaching a heat dissipation member 24 as a heat dissipation means. Although this method is natural cooling as in the above-described embodiment, since the heat dissipation in the heat radiating means is large, an increase in the temperature of the entire scanner housing can be suppressed.
In the figure, the heat radiating member 24 has a fin-like shape, but a metal plate having a similar function by processing a sheet metal or a heat radiating sheet may be used.
In order to facilitate understanding, the longitudinal direction of the fin is shown in the horizontal direction in the figure, but this direction does not have to be horizontal. In the case of using a fin-shaped heat radiating member, the direction of the fin is preferably directed in the vertical direction in order to efficiently generate natural convection of air.
According to this configuration, not only the heat from the CCD substrate but also the heat transmitted from the light source lamp or the like to the scanner housing can be efficiently radiated.

FIG. 4 is a view for explaining still another embodiment of the present invention.
In the figure, reference numeral 25 denotes a cooling fan, and 26 denotes a fan cover.
A further cooling effect can be obtained by attaching a cooling fan 25 or the like as a heat radiating means to the scanner casing 22 having the configuration shown in FIG. 2 and forcibly cooling the outside of the scanner casing. The direction of the air may be a direction in which air is applied to the scanner housing or a direction in which air is sucked out from the scanner housing. A fan cover 26 having a hole at a predetermined position restricts the flow of air so that the air efficiently strikes the scanner housing.
Although the cooling fan is directly attached to the casing in this figure, the casing may be cooled by using a duct-like object and applying the wind of the cooling fan.
According to this configuration, in addition to the effects of the above-described embodiments, only the outside of the scanner housing is cooled using a fan, so that the inside of the machine is not contaminated by outside air, and an increase in abnormal images can be prevented. it can.

FIG. 5 is a view for explaining still another embodiment of the present invention.
In the same figure, the code | symbol 27 shows a heat sink cover.
In the configuration shown in the figure, a cooling fan 25 is attached in the vicinity of the heat radiating plate 24 having the configuration shown in FIG. The figure shows an example in which the fin-shaped heat radiating plate 24 has the fins oriented in the vertical direction. The direction of the wind can be reduced by making it sucked from the fin side. The heat radiating plate 24 regulates the air flow with a heat radiating plate cover 27 having holes at predetermined positions so that the inflowing air efficiently hits the heat radiating plate 24.
When the image reading apparatus according to each of the embodiments described above is adopted in an image forming apparatus, the image reading apparatus having good heat dissipation of the CCD and capable of continuous reading is mounted. The service life is improved. .

1 is a diagram illustrating an overall layout of a configuration of an image reading apparatus to which the present invention is applied. It is a figure for demonstrating one Embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention. It is a figure for demonstrating other embodiment of this invention.

Explanation of symbols

20 CCD
21 CCD substrate 22 Scanner housing 23 Thermal conductor 24 Heat sink 25 Cooling fan

Claims (6)

  In a digital image reading apparatus that scans an original and converts optical information of an image into an electrical signal using a CCD image sensor, a part of a heat conductor is brought into contact with the casing of the CCD image sensor, and the heat An image reading apparatus, wherein another part of the conductor is brought into contact with the inside of the scanner housing.   The image reading apparatus according to claim 1, further comprising a cooling unit that cools a vicinity of a part of the thermal conductor of the scanner housing that is in contact with the image reading apparatus.   The image reading apparatus according to claim 2, wherein the cooling unit is a heat radiating member attached to the outside of the scanner casing.   3. The image reading apparatus according to claim 2, wherein the cooling means is a cooling fan attached to the outside of the scanner casing.   4. The image reading apparatus according to claim 3, wherein the cooling unit includes a cooling fan for cooling the heat radiating member.   An image forming apparatus using the image reading apparatus according to claim 1.

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