JPH0946487A - Original reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and light-weight original reader at low cost to read the originals at high speed by using a cooling means to keep the member of the reader at a prescribed temperature and therefore attaining the use of the resin component parts. SOLUTION: An air duct 9b is contained in an original reader 1, and a cooling device is prepared at an air intake 9c of the duct 9b. A pump 9a is started with braking by a thermostat 10 to supply the cooling air into the intake 9c. Then the cooling air is sent to such optical component parts as the reflectors M2, M3 and M4, an optical receptor 5d, an original mounting glass 2, a projection lens 5c, etc., through the nearby air ducts 9b11 and 9b21. Thus the temperature is kept at 50 deg.C or less or the difference of temperature is kept at 50 deg.C or less against the outside air. Thus, even the resin component parts of the reader 1 never suffer the thermal deformation, deterioration and characteristic change. In such a constitution, a compact and light-weight device 1 is obtained at low cost and therefore can read at high speed the orginals owing to this compact/light-weight structure and also can improve the stability of picture quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine,
The present invention relates to a document reading device used for a facsimile transmitter, a scanner and the like.

[0002]

2. Description of the Related Art A document reading apparatus used in, for example, a copying machine, a document table supporting a document, a light source facing the document table and illuminating the document, and reflected light reflected by the document illuminated by the light source. Some have at least one photoreceptor for receiving light and an optical component for collecting or guiding the reflected light to the photoreceptor.

[0003]

In such a document reading apparatus, the components such as the holder of the light source, the reflection mirror of the light source, the mirror holding member and the like are formed of a metal material such as an extruded aluminum material or a pressed material. It is heavy, and it has a high manufacturing cost due to molding.

Further, in the document reading apparatus, high-speed reading is demanded. For example, for high-speed reading, if the components of the reading / scanning system are heavy, the scanning drive system becomes large and the moment of inertia is large. In addition to complicated and difficult braking and drive control at the time of reciprocating scanning, there is a problem in that the vibration unique to the large moment of inertia has a great influence on the reading accuracy of the document and cannot be ignored.

Therefore, in order to increase the speed, it is conceivable that, for example, the components of the reading and scanning system are made of resin to reduce the weight, or the irradiation light quantity of the light source is increased, but in order to increase the irradiation light quantity, Increasing the output of the light source causes a rise in temperature of surrounding components and photoreceptors. Moreover, as the temperature rises, in particular, the resin component parts may be heated, deformed, deteriorated, or changed in characteristics, or the document mounting glass may be deformed, resulting in unstable image quality.

When the original placing glass is heated to a high temperature, the original placing glass is burned when touched by a hand or the like when placed on the original placing glass, or the original is deformed or discolored under the influence of heat. There is a risk of doing it.

Conventionally, cooling is performed by a cold air fan or the like in order to lower the space temperature of the entire inside of the original reading device. However, only the cooling by such a cold air fan or the like constitutes the inside of the original reading device. Measures against parts and photoreceptors, especially optical system parts that require high-precision processing and mounting drive stability are insufficient.

The present invention has been made in view of the above points, and it is possible to suppress the influence of heat, reduce the cost, reduce the size, and reduce the weight, improve the stability of the image quality, and read the original at high speed. It is an object of the present invention to provide a document reading device that does.

[0009]

In order to solve the above-mentioned problems and to achieve the object, a document reading apparatus according to the invention of claim 1 has at least a document table supporting a document and a document table facing the document table. A light source and a reflecting mirror that illuminate the document, at least one photoreceptor that receives the reflected light reflected by the document that is illuminated by the light source, and the reflected light is condensed on the photoreceptor or It is characterized by having an optical component for guiding and a temperature maintaining means for directly maintaining the temperature of at least one of this component, the reflector or the photoreceptor.

As the light source, for example, a halogen lamp, a xenon lamp, a fluorescent lamp is used, and the photoreceptor is
Indicates an object on the optical path of the reflected light reflected in the original illuminated by the light source, a light reflector that re-reflects the reflected light to another photoreceptor, a lens that converges or diffuses the reflected light, A typical example thereof is a photoelectric conversion element that converts reflected light into an electric signal. In addition, the component parts
It is a component that composes a document reading device excluding a light source and a photoreceptor. By maintaining the temperature of at least one of the component, the reflecting mirror or the photoreceptor directly by the temperature maintaining means and suppressing the influence of heat, the component or the photoreceptor can be manufactured at low cost,
In addition to downsizing and weight reduction, the stability of image quality is improved and high-speed reading of originals becomes possible.

According to a second aspect of the present invention, the document reading apparatus is characterized in that the temperature maintaining means maintains the temperature of at least one of the component, the reflecting mirror and the photoreceptor at 50 ° C. or lower. There is.

As described above, by maintaining the temperature of at least one of the component parts, the reflecting mirror or the photoreceptor at 50 ° C. or lower, the resin component parts are heated, deformed, deteriorated or changed in characteristics, or the original document is manufactured. It is possible to prevent the mounting glass from being deformed and the image quality from becoming unstable, so that the original can be read at high speed.

In the document reading apparatus according to the third aspect of the present invention, the temperature maintaining means causes the temperature difference between the temperature of at least one of the constituent parts, the reflecting mirror or the photoreceptor and the temperature of the outside air to be 50 ° C. It is characterized by maintaining the following.

The outside air refers to the space outside the document reading apparatus. The temperature of the outside air is usually equal to room temperature, 25 ° C. is standard, but it is about 10 ° C. to 40 ° C. depending on the use environment. It is preferable that the range varies.

As described above, the temperature maintaining means includes the components,
By keeping the temperature difference between at least one of the reflecting mirror or the photoreceptor and the outside air at 50 ° C or less, the resin component is heated, deformed, deteriorated, changed in characteristics, or deformed on the original placing glass. It is also possible to prevent the image quality from becoming unstable and to read the original at high speed.

The document reading apparatus according to a fourth aspect of the present invention is characterized in that the temperature maintaining means is a cooling means for directly cooling the component, the reflecting mirror or the photoreceptor.

The cooling means is for cooling the parts whose temperature rises, and includes cooling by air, cooling by a refrigerant, and other means. Examples of the air cooling means include a cooling fan and an air duct configured to directly introduce the cool air toward at least one of the component, the reflecting mirror, and the photoreceptor. Further, as the cooling means by the cooling medium, there is, for example, a cooling device utilizing adiabatic expansion for directly cooling at least one of the component, the reflecting mirror and the photoreceptor, and the cooling device using at least one of the component, the reflecting mirror and the photoreceptor. There is a heat pipe that removes heat. Further, as cooling means other than cooling by air and cooling by a refrigerant, there is a thermoelectric element such as a Peltier element configured to directly cool at least one of the component, the reflecting mirror and the photoreceptor.

As described above, the cooling means is a means for directly cooling at least one of the component parts, the reflecting mirror or the photoreceptor, and is selected from a cooling fan, an air duct, a cooling device, a heat pipe, a thermoelectric element and the like. Attaching one to at least one of the components, reflector or photoreceptor is a common means of cooling.

The cooling fan is driven by a drive source,
At least one of the component, the reflecting mirror, and the photoreceptor is introduced with external air and blown, or the air in the document reading apparatus is exhausted to the outside of the apparatus, so that At least one of them is maintained at a constant temperature or the difference between the temperature inside the device and the temperature of the outside air is made small.

In the heat pipe, one end of the pipe in which the heat-conducting medium is enclosed is attached directly to or in the vicinity of at least one of the component, the reflecting mirror and the photoreceptor, and the other end of the pipe is connected to a heat source to generate heat. By circulating the conducting medium in the pipe, it is possible to cool at least one of the component, the reflector or the photoreceptor through the heat conducting medium in the pipe. A fluid such as water, mineral oil, vegetable oil, chlorofluorocarbon gas, carbon dioxide, or air can be arbitrarily selected as the heat conduction medium enclosed in the pipe, but at least one of component parts, reflecting mirror or photoreceptor or device The most preferable one is selected in consideration of the temperature to be maintained inside, the temperature of the outside air, the safety, toxicity, and handleability of the heat transfer medium. For example, the outside air temperature is 25 ° C, the temperature to be maintained in the device is 50 ° C or less, and the maximum temperature of the heat generation source is 400 ° C.
In the case of, water in which an additive for raising the boiling point is dissolved is preferably used. The power to circulate the heat transfer medium in the heat pipe can use an independent drive source, but it is also possible to use a pump driven as the components move.

The thermo-electromotive element, by passing an electric current,
An element that absorbs or generates heat by the Peltier effect or the Thomson effect, and is attached directly to or in the vicinity of at least one of the components, the reflector or the photoreceptor. The thermoelectric element is generally an element in which dissimilar metals are joined, but at least one of a component, a reflecting mirror or a photoreceptor or the temperature to be maintained in the device and the temperature of the outside air, a unit of a heat generation source. The most preferable one is selected in consideration of the amount of heat generated per time, but those in which platinum and a platinum / 10% rhodium alloy are joined and those in which chromel alloy and alumel alloy are joined are generally used.

As described above, by directly cooling at least one of the component, the reflecting mirror and the photoreceptor by the cooling means, the resin component is heated, deformed, deteriorated, changed in characteristics, or placed on the original placing glass. To prevent the image from becoming deformed or the image quality becoming unstable.

According to a fifth aspect of the present invention, in the document reading apparatus, the temperature maintaining means is a heat insulating means that directly blocks heat transfer to at least one of the component, the reflecting mirror or the photoreceptor. Is characterized by.

The heat insulating means is means for cutting off heat transfer from the heat generating source, and a typical means is heat radiation blocking means for blocking the heat radiation from the heat generating source. As the heat insulating means, for example, a component, a reflecting mirror or a heat insulating material that is arranged at a connection portion connected to a photoreceptor and blocks heat transfer through the component,
In addition, it is made of a heat insulating material that is placed between the components and between the reflector and the photoreceptor to block heat transfer through the air, and the device body has an airtight structure, and the device body has a vacuum atmosphere. be able to.

Further, the heat insulating means may be composed of a coating for blocking heat radiation deposited on at least one of the component, the reflecting mirror and the photoreceptor.

As described above, the heat insulating means is a means for cutting off heat transfer from the heat generation source to at least one of the component, the reflecting mirror and the photoreceptor, and the heat insulating material is used as the component, the reflecting mirror or the photoreceptor. It is a general means as a heat insulating means to be provided around at least one of the above.

There is a method of forming a vacuum layer as the heat insulating material. The vacuum layer is to provide a vacuum layer between the heat generation source and the object whose temperature is maintained, and to provide a closed space between the heat generation source and the object whose temperature is maintained, and to vacuum the closed space. And a means for making a space containing a heat generation source and an object whose temperature is maintained airtight, and making a vacuum in the entire enclosed space including the heat generation source and an object whose temperature is maintained. is there. At this time, if the atmospheric pressure of the vacuum layer is 50 Pa or less, a heat insulating effect can be obtained, but it is preferably maintained at 0.1 Pa to 0.001 Pa in consideration of equipment for vacuum maintenance and the heat insulating effect.

As described above, by vacuuming the inside of the document reading apparatus, in addition to the heat insulation effect, dust and dust are less adhered to the constituent parts, and air is used in driving the constituent parts. Resistance is reduced and smooth high speed operation is possible. Further, even if a component that is easily subjected to air oxidation is used, it is possible to use a photoelectric conversion element that does not easily deteriorate, has low heat resistance, and is easily air-oxidized.

As the heat insulating material, a material having a low thermal diffusivity is generally used. Asbestos, titanium carbide, zirconium silicate, boron carbide, etc. are mentioned, but titanium carbide is black and absorbs scattered light, so it prevents flare and suppresses heat transfer from heat generation source to other parts. It has a great effect and is preferably used in a document reading device. Further, by enclosing a gas having a low thermal conductivity such as carbon dioxide, freon, xenon, or chlorine in the document reading device, it is possible to use it as a heat insulating material.

The heat radiation blocking means is a means for blocking heat radiation from the heat generation source to at least one of the component, the reflecting mirror and the photoreceptor, and the heat radiation reflecting layer for reflecting the heat radiation and absorbing the heat radiation. However, it is general to provide a thermal radiation absorbing layer that converts electrical and chemical energy around at least one of the component, the reflecting mirror and the photoreceptor as the thermal radiation blocking means. The heat radiation reflection layer reflects heat radiation such as infrared rays and microwaves emitted from the heat generation source, and at least one of component parts, a reflecting mirror or a photoreceptor or an object for controlling the temperature is a heat generation source. Prevents radiant heat from being generated. A gold vapor deposition film as the thermal radiation reflection layer,
Aluminum vapor deposition film and silver vapor deposition film are generally used.

As described above, by directly cooling at least one of the component, the reflecting mirror and the photoreceptor by the heat insulating means, the resin component is heated, deformed, deteriorated, changed in characteristics, or placed on the original mounting glass. To prevent the image from becoming deformed or the image quality becoming unstable. In addition, the cooling means and the shutoff means,
It is also possible to use them together so long as the function of each means is not lost.

The document reading apparatus according to the sixth aspect of the present invention is characterized in that the constituent parts are parts constituting the document reading apparatus excluding the light source, the reflecting mirror and the photoreceptor. The components include a light source and a member that supports them, a holder that holds a part of a driving unit when driving, a holder that holds a mirror, a light source code, sensors, and the like. By cooling the components, it is possible to prevent the components from being heated, deformed, altered, changed in characteristics, and unstable in image quality.

According to a seventh aspect of the present invention, there is provided a document reading apparatus characterized in that at least one of the component, the reflecting mirror and the photoreceptor has a member made of resin. In this way, by directly cooling the component, the reflector or the photoreceptor, it can be formed of resin,
Even when it is formed of this resin, it is possible to prevent heating, deformation, deterioration, and characteristic changes, the image quality is stabilized, and since the component parts are made of resin, the weight is reduced, and high-speed reading becomes possible.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the document reading apparatus of the present invention will be described below. The document reading apparatus of this embodiment is used for a copying machine, but is not limited to this and is also used for a facsimile transmitter, a scanner and the like with a similar configuration.

FIG. 1 is a schematic configuration diagram of the document reading device, FIG. 2 is a perspective view of the document reading device with a document cover opened, and FIG.
FIG. 3 is a plan view of the document reading device with a document cover removed. This document reading device 1 is provided in a copying machine, a document table is provided above the document reading device 1, and a document placing glass 2 corresponding to the size of a sheet document of a specified size is fixedly installed. A document cover 90 is provided so as to be openable and closable around the fulcrum. Light receiving elements 91a to 91g are provided on the upper back surface of the document reading apparatus 1, and these light receiving elements 91a are provided.
Reflectors 92a and 92b are attached so as to be openable and closable on the upper surface of the to 91g. The light-emitting element 9 is provided on the lower portion of the light receiving elements 91a to 91g with the original placing glass 2 interposed therebetween.
3a to 93g are provided. Light emitting elements 93a to 93
After passing through the document placing glass 2, the light of g is reflected by the reflector 92.
The light is reflected by a and 92b and is received by each of the light receiving elements 91a to 91g. Each pair of the light receiving elements 91a to 91g and the light emitting elements 93a to 93g constitutes a sensor, and the light receiving elements 91a to 91g and the light emitting elements 93a to 93g are document detection sensors corresponding to a plurality of document sizes, and the light receiving element 91g. The light emitting element 93g is an open / close detection sensor that detects the open / closed state of the document cover 90.

Below the original placing glass 2, an exposure lamp L which is a light source, a concave mirror Ml, a first mirror unit 5a having a reflecting mirror M2, a reflecting mirror M3, and a second mirror unit 5b having a reflecting mirror M4. Further, an exposure optical system 5 including a projection lens 5c and a reflecting mirror 5d and an image sensor 6 are provided. A light source cord 94 is connected to the exposure lamp L.

The sheet original has the original surface with the original placing glass 2
After being fixed so as to face the upper surface, the first mirror unit 5a and the second mirror unit 5b move to the position of the alternate long and two short dashes line to expose and scan the original surface of the sheet original on the original stacking glass 2, Image is formed on the surface of the image pickup device 6 by the projection lens 5c via the reflection mirror 5d, and the image pickup device 6 converts the image formed on the surface into an electric signal to read the original. Sensors 95 to 97 for position detection are provided in the exposure scanning system of the first mirror unit 5a and the second mirror unit 5b.

A louver 98 for taking in air is provided on the side wall of the document reading apparatus 1, and a cooling fan 99 is provided on the opposite side wall to cool the entire inside of the document reading apparatus 1.

An air duct 9 is provided inside the document reading apparatus 1.
b is arranged. A pump 9a activated by a thermostat 10 is arranged on the air intake 9c side of the air duct 9b. The air duct 9b has an air blowing portion 9b1 extending below the original placing glass 2 and an air blowing portion 9b2 extending above the projection lens 5c. The air blowing portion 9b1 of the air duct 9b has an air outlet 9b11 near the lower surface of the original placing glass 2, and the air blowing portion 9b2 of the air duct 9b has a first mirror unit 5a, a second mirror unit 5b, and a projection unit. The air outlet 9b is provided in the vicinity of the lens 5c, the reflection mirror 5d, and the image sensor 6.
21. When the temperature inside the document reading device 1 reaches a predetermined temperature or higher, the thermostat 10 starts the pump 9a, and the driving of the pump 9a removes the outside air from the air duct 9.
From b to the document mounting glass 2, the first mirror unit 5a, the second mirror unit 5b, the projection lens 5c, the reflection mirror 5
It is sprayed on d and the image pickup device 6 to reduce the temperature difference from the outside air.

In this document reading apparatus 1, a cooling condenser 11 can be arranged on the air intake 9c side of the air duct 9b as shown in FIG. The cooling condenser 11 has a compressor and a condenser, and cools the air with the liquefied refrigerant, so that the cooled air is sent through the pump 9a and the air duct 9b to improve the cooling effect.

5 and 6 show another embodiment of the document reading device, FIG. 5 is a schematic configuration diagram of the document reading device, and FIG. 6 is a principle diagram of a cooling device utilizing adiabatic expansion. This document reading device 1 is an embodiment in which it is cooled by a refrigerant. In this document reading apparatus 1, the members denoted by the same reference numerals as those in FIG. The document reading apparatus 1 includes a first mirror unit 5a and a second mirror unit 5
A cooling device A utilizing adiabatic expansion is arranged corresponding to the position where b is stopped, the position above the projection lens 5c, and the positions of the reflection mirror 5d and the image sensor 6. The cooling device A includes cooling fins 12a and a device body 12b. Compressed air is sent from the compressed air supply mechanism B to the device body 12b and cooled by the cooling device A by utilizing adiabatic expansion. The compressed air supply mechanism B is composed of, for example, a compressor, and when the internal temperature of the document reading apparatus 1 reaches a predetermined temperature or higher, a solenoid valve 15 provided in the supply pipe 14 by the thermostat 13 is provided.
Is operated to control the supply of compressed air.

The principle of the cooling device A will be described with reference to FIG. An orifice 17 is provided at one end of the tube body 16, a donut-shaped gap 18 is provided at the end portion, and an air supply port 19 is provided at the middle abdominal portion near the one end. When the compressed air X is blown into the pipe body 16 from the air supply port 19, a super-high speed vortex 20 is formed in the pipe body 16. Therefore, a large pressure difference is generated between the central portion and the outer peripheral portion of the vortex 20, air is moved toward the central portion, and the temperature is lowered by adiabatic expansion. The low temperature air Y generated in the central portion flows out from the orifice 17, and the high temperature air Z in the outer peripheral portion is discharged from the donut-shaped gap 18. The cooling device A varies depending on the model and the pressure of the compressed air X supplied, etc.
By supplying air at a specified pressure, the temperature will rise from room temperature to 4
It is possible to easily generate low temperature air that is as low as 0 to 50 ° C. The cooling device A is an application of the vortex theory, and is a dew condensation type cooler that utilizes a temperature decrease due to adiabatic expansion of compressed air.

7 to 9 show still another embodiment of the cooling of the document reading device by the refrigerant, FIG. 7 is a schematic configuration diagram of the document reading device, and FIG. 8 shows cooling of the first mirror unit by a heat pipe. FIGS. 9A and 9B are diagrams showing cooling of the second mirror unit, the projection lens, the reflection mirror, and the image sensor by the heat pipe. This document reading device 1 is an embodiment in which it is cooled by a refrigerant. In the document reading apparatus 1, the members denoted by the same reference numerals as those in FIG. The document reading apparatus 1 includes a heat pipe 30 for cooling the first mirror unit 5a, a second mirror unit 5b, a projection lens 5c, a reflection mirror 5d, and an image sensor 6.
A heat pipe 40 for cooling is disposed.

The heat pipe 30 for cooling the first mirror unit 5a is attached as shown in FIG.
That is, the heat pipe supporting portion 32 is integrally formed with the opening forming portion 33 and the reflecting mirror portion 31 on the reflecting mirror portion 31 of the first mirror unit 5a by using the same resin. . The heat pipe supporting portion 32 is preferably a long one having the same length as the reflecting mirror portion 31, and has a hollow portion 34 into which the heat pipe 30 is inserted and a cut portion 35 continuous with the hollow portion 34. Then, the plate wall of the cut portion 35 is fastened with a screw 36 so that the heat pipe 30 is closely held on the inner wall surface of the hollow portion 34. The inside of the heat pipe 30 is, for example, a groove type wick, and water, for example, is filled as a working liquid inside, and heat radiation fins 37 are attached to the ends of the heat pipe 30 to remove the heat taken by the heat pipe 30. Is designed to radiate heat. Since the heat pipe support portion 32 is integrated with the reflecting mirror portion 31 and the opening forming portion 33 is integrated with the reflecting mirror portion 31, the heat of the molded product is extremely easily transferred to the heat pipe 30. Moreover, since the heat pipe 30 is provided over substantially the entire length of the reflecting mirror portion 31, the molded product is uniformly cooled in the longitudinal direction of the exposure lamp L, and the temperature of the glass 38 and the ambient temperature around the first mirror unit 5a. Can also be suppressed.

Second mirror unit 5b, projection lens 5
The heat pipe 40 for cooling the c, the reflection mirror 5d, and the image pickup device 6 is attached as shown in FIG. That is, the heat pipe 40 runs in the vicinity of the second mirror unit 5b from the front side to the back side of the device and is bent.
a, 40b, the heat absorbing part 40c running near the projection lens 5c from the front side to the back side of the apparatus and bent at the back side, and the vicinity of the reflection mirror 5d and the image pickup element 6 bent from the front side to the back side of the apparatus. The heat absorbing parts 40d and 40e are combined with a collecting part 40f.

A fin 41 and a heat dissipation fan 42 for improving heat dissipation efficiency in the heat dissipation parts 40a to 40e are connected to the heat dissipation part 40g connected to the collecting part 40f of the heat pipe 40. The heat pipe 40 is configured by lowering the pressure inside the metal pipe having high thermal conductivity and enclosing the heat medium liquid therein, and the heat absorbing parts 40a and 40b are radiated from the second mirror unit 5b, and the heat absorbing part 40c is projected onto the projection lens. When the heat absorbing parts 40d and 40e are heated by the radiant heat from the reflection mirror 5d and the image pickup device 6 by the radiant heat from the 5c, the heat transfer liquid inside the pipe is vaporized, and at that time, a large amount of heat of vaporization is taken away. The saturated vapor of the heat transfer medium thus generated reaches the collecting portion 40f, where it radiates heat and is reliquefied. The liquefied heat medium liquid propagates along the inner wall surface of the collecting portion 40f by gravity or a capillary phenomenon and returns to the heat absorbing portions 40a to 40e again. By repeating this cycle, the heat absorbing portion 40
The heat generated in the a to 40e is instantaneously transferred to the heat exhausting unit 40g without raising the temperature in the device, and the fins 41a
From the exhaust heat fan 42 to the exhaust port 43
Is efficiently exhausted from.

10 and 11 show another embodiment of the document reading apparatus, and FIG. 10 is a schematic configuration diagram of the document reading apparatus, FIG.
1 is a principle diagram of a cooling device using a thermoelectric element. This document reading apparatus 1 is an embodiment in which a Peltier element as a thermoelectromotive element is used for cooling. In the document reading device 1,
Members given the same reference numerals as those in FIG. As shown in FIG. 10, the document reading apparatus 1 includes a cooling device C attached to cool the first mirror unit 5a, a cooling device D attached to cool the second mirror unit 5b, and a projection device. Lens 5c
A cooling device E attached to cool the image pickup device, a reflection mirror 5d, and a cooling device F attached to cool the image sensor 6 are arranged.

Each of the cooling devices C to F is a specific example of cooling a member with a Peltier element, and is constructed as shown in FIG. In the figure, 50 is a heat dissipation plate, 51 is a metal piece terminal plate made of a material having good thermal conductivity and electrical conductivity, for example, pure copper, 52 is a Peltier element which is a thermoelectric element, 53 is a terminal plate, 54 Is an insulating plate such as a ceramic insulating substrate, which has good thermal conductivity but is a poor conductor of electricity, 56
Is a member to be cooled, 62 is a temperature detection circuit, 63 is a temperature control circuit, and V is a power source. The temperature detection circuit 62 sends a signal to the temperature control circuit 63 to cool the member 56 to be cooled if the temperature of the member 56 to be cooled is higher than the standard operating temperature. The temperature control circuit 63 supplies a current to the Peltier element 52, and when the Peltier element 52 is energized, a heat dissipation phenomenon occurs at the joint surface with the terminal plate 53 and is dissipated by the heat dissipation plate 50, and a heat absorption phenomenon occurs at the joint surface with the terminal plate 51. Occurs and cools down. Generally, the temperature of the first mirror unit 5a, the second mirror unit 5b, the projection lens 5c, the reflection mirror 5d and the image pickup device 6 which are the members to be cooled rises, so that only cooling is performed as in this embodiment. However, it is also possible to heat the member 56 to be cooled by passing a current through the Peltier element in the opposite direction to the above.

12 to 15 show another embodiment of the document reading device, FIG. 12 is a perspective view of the document reading device, FIG. 13 is a schematic configuration diagram of the document reading device, and FIG. 14 is attachment of a document placing glass. FIG. 15 is an enlarged cross-sectional view of the drive section, and FIG. 15 is an enlarged cross-sectional view of the drive section.

In this document reading apparatus 1, the apparatus main body 70 is formed of a pressure wall, has an airtight structure, and is in a vacuum state.
When reading a sheet original, the original reading apparatus 1 moves the sheet original inserted into the feed roller 3b to the left on the original placing glass 2 by the conveyor belt 3a.

A drive motor 71 is arranged in the upper portion inside the apparatus main body 70, and the power of the drive motor 71 is transmitted to the scanning mechanism 73 via a belt 72. By the operation of the scanning mechanism 73, the first mirror unit 5a and the second mirror unit 5b expose and scan the image of the document surface moving on the document mounting glass 2, and the projection lens 5c causes the protection filter unit 7 and the reflection mirror 5d to move. An image is formed on the surface of the image sensor 6 via the image sensor 6, and the image sensor 6 converts the image formed on the surface into an electric signal.

The original placing glass 2 is placed so as to cover the upper wall opening 70a of the apparatus main body 70, and the original placing glass 2 is placed.
The end portion 2 a of the is supported via a stopper 74. An O-ring 7 is provided between the document placing glass 2 and the apparatus main body 70.
5 is interposed and sealed by this O-ring 75, so that the inside of the apparatus main body 70 has an airtight structure. In this way, the apparatus main body 70 and the original placing glass 2 are hermetically sealed, and the flow of gas with the outside air is extremely small. An exhaust duct 76 is connected to the side wall of the device body 70.
In FIG. 6, a diffusion pump 77 and a rotary pump 78 are sequentially arranged from the upstream side to the downstream side. The diffusion pump 77 and the rotary pump 78 are driven to evacuate, and the inside of the apparatus main body 70 having an airtight structure becomes a vacuum state. The atmospheric pressure is maintained at 0.1 Pa vacuum. Either one of the diffusion pump 77 and the rotary pump 78 may be used, and generally only the rotary pump 78 is used.

The drive motor 71 is cooled by the cooling device G. The cooling device G has a heat receiving portion 80a through which a refrigerant circulates and a heat radiating portion 80b. The heat receiving portion 80a is arranged inside the device body 70, and the heat radiating portion 80b is arranged outside the device body 70. The heat of the drive motor 71 is absorbed by the heat receiving portion 80a, and is dissipated by the heat dissipation plate 81 of the heat dissipation portion 80b to cool the drive motor 71.

Aluminum is vapor-deposited on the light-reflecting surfaces of the first mirror unit 5a and the second mirror unit 5b, which reflects the heat radiation emitted from the exposure lamp L, so that each of the first mirror unit 5a and the second mirror unit 5b. The unit 5b is configured to minimize the heat generation of itself. Further, a titanium carbide pigment is applied as a heat insulating material and a scattered light absorbing material to the non-reflective portions of each of the first mirror unit 5a and the second mirror unit 5b, and flare due to light scattering and inside the device body 70 due to heat conduction. Suppresses the temperature rise.

As an example, FIG. 16 shows an example of the first mirror unit 5a. Aluminum is vapor-deposited on the light reflecting surfaces of the concave mirror M1 and the reflecting mirror M2 to form a coating C1 for blocking heat radiation, and the concave mirror M1 and the reflecting mirror M2 are also formed.
A titanium carbide pigment is applied to the surface opposite to the light reflection surface of the above, or a ceramic is provided to form a coating C2.

An example of the first mirror unit 5a is
As shown in FIG. In the figure, an exposure lamp L such as a halogen lamp for irradiating an original on the original placing glass 2 is provided below the original placing glass 2. Exposure lamp L
Is surrounded by a reflector 85 so that the light emitted from the exposure lamp L is focused on the original side, and between the exposure lamp L and the original placement glass 2. A light-shielding plate 86 having a slit 86a for transmitting the light from the exposure lamp L is provided, and a reflection tape 87 or the like is attached to the side surface of the light-shielding plate 86 that is projected above the exposure lamp L. As a result, the reflecting surface 87a is formed. Reference numeral 88 is a lens. As described above, since the reflection tape 87 is attached to the side surface of the light source such as the light shielding plate 86 provided near the exposure lamp L to form the reflection surface 87a, the radiant heat from the exposure lamp L is reflected. The light is reflected by the surface 87a, so that the light shielding plate 86 does not reach a high temperature, no extra space is required, and the cost is low.

Next, an example of the protection filter unit 7 will be described.
As shown in FIG. The protection filter unit 7 has a configuration in which a Peltier element 7b for cooling the protection filter 7a is mounted around a protection filter 7a made of a resin plate having a thickness of 3 mm and having a blue pigment dispersed therein. The Peltier element 7b is formed by joining platinum and platinum / 10% rhodium, and a current is passed through the Peltier element 7b.
The temperature rise of the protection filter 7a is suppressed.

The original read by the original reading device 1 is not limited to the sheet original shown in the embodiment, and includes a three-dimensional original. Further, the document reading apparatus 1 of this embodiment forms an image on the surface of the image sensor 6 via the reflection mirror 5d, and the image sensor 6 converts the image formed on the surface into an electric signal. The same can be applied to the case of an analog type copying machine which forms an image on the photosensitive drum from the reflecting mirror 5d without using the element 6 and performs exposure.

Further, in the document reading apparatus 1 of each of the above-described embodiments, the temperature of at least one of the component parts and the photoreceptor is maintained at 50 ° C. or lower. The components are components that constitute the document reading device 1 excluding the light source and the photoreceptor as described above. This component includes a member made of resin.

At least one member of the component parts or the photoreceptor of the document reading device 1 suppresses the influence of heat on the document reading device, thereby achieving low cost, downsizing and weight saving, and stability of image quality. The temperature is maintained at 50 ° C. or lower for improvement and high speed reading.

At least one of the components of the document reading apparatus 1 or the photoreceptor is made of resin such as polyethylene terephthalate (PET) or polycarbonate (PC) for weight saving.

These members are affected by heat, and from the viewpoint of thermal expansion, the coefficient of thermal expansion (10 ⁻⁶ / ° C.) is as follows: Aluminum alloy: 25 Polyethylene terephthalate (PET): 70 Polycarbonate (PC): 65.

For example, when a plate material having a length of 300 mm is molded at 20 ° C., the length (mm) at each temperature is as follows: temperature 20 ° C. 50 ° C. 80 ° C. 120 ° C. Aluminum alloy 300 300.2 300.3 300.6 PET 300 300 6 301.1 302.1 PC 300 300.5 300.9 301.8.

The amount of deformation observed at 120 ° C. in the aluminum alloy was observed at 50 ° C. in PET and PC,
If the resin-made component or photoreceptor is not maintained below 50 ° C., the amount of deformation will be large.

That is, the aluminum alloy, polyethylene terephthalate (PET) and polycarbonate (P
When a reflection mirror is molded with the plate material of C) and fixed with a thermal expansion margin of 1 mm, it is 1 for aluminum alloy.
Even if the expansion amount is less than the margin even at 20 ° C., no problem occurs, but in polyethylene terephthalate (PET) and polycarbonate (PC), the amount exceeding the margin is absorbed as the deformation of the plate material, and as shown in FIG. , The mirror angle is polyethylene terephthalate (PE
T) about 4.9 degrees, polycarbonate (PC) about 4.
It changes twice and the optical path is significantly different from that set at 20 ° C., so that normal reading of the original cannot be performed.

When the mirror is fixed with a margin of about 1 mm, polyethylene terephthalate (PET) is 70
It is required that the temperature is maintained at or below 0 ° C, and that for polycarbonate (PC) is maintained at or below 80 ° C.

Further, the coefficient of thermal expansion (10 ^-6 / ° C.) of vinyl chloride, which is often used for coating the light source cord and the like, is 8
0. A vinyl coating that was 1 m at 20 ° C. will expand 8 mm at 120 ° C. If the length changes by this amount, the connection with the substrate may be lost.

[0068]

As described above, according to the first aspect of the present invention, at least one photoreceptor that receives the reflected light reflected from the original illuminated by the light source, and the reflected light is collected to this photoreceptor. It has an optical component for guiding light or light and temperature maintaining means for directly maintaining the temperature of at least one of this component, the reflecting mirror or the photoreceptor, and the temperature maintaining means allows the component, the reflecting mirror Alternatively, by directly maintaining at least one temperature of the photoreceptor and suppressing the influence of heat, the cost, size and weight of the component, reflecting mirror or photoreceptor can be reduced, and the stability of the image quality can be improved. Thus, the document can be read at high speed.

According to a second aspect of the invention, the temperature maintaining means comprises:
By maintaining the temperature of at least one of the component parts, the reflecting mirror or the photoreceptor at 50 ° C. or lower, the resin component parts are heated, deformed, deteriorated, changed in characteristics, or deformed on the original placing glass. It is possible to prevent the image quality from becoming unstable, and it becomes possible to read the original at high speed.

According to the invention of claim 3, the temperature maintaining means comprises:
By maintaining the temperature difference between the temperature of at least one of the component, the reflecting mirror or the photoreceptor and the temperature of the outside air at 50 ° C. or less, the resin component is heated, deformed, deteriorated, changed in characteristics, or It is possible to prevent the original placing glass from being deformed and the image quality from becoming unstable, so that the original can be read at high speed.

According to a fourth aspect of the invention, the temperature maintaining means comprises:
A cooling means for directly cooling the component, the reflecting mirror or the photoreceptor, and by directly cooling at least one of the component, the reflecting mirror or the photoreceptor by the cooling means, the resin component is heated or deformed, It is possible to prevent alteration, characteristic changes, deformation of the document placing glass, and instability of image quality.

According to the invention of claim 5, the temperature maintaining means comprises:
A heat insulating means for directly blocking heat transfer to at least one of the component, the reflecting mirror and the photoreceptor, and by directly cooling at least one of the component, the reflecting mirror and the photoreceptor by the heat insulating means, the resin It is possible to prevent the manufactured component parts from being heated, deformed, altered, or changed in characteristics, deformed on the original placing glass, and become unstable in image quality.

According to a sixth aspect of the present invention, the constituent parts are constituent parts of the document reading device excluding the light source, the reflecting mirror and the photoreceptor, and as the constituent parts, for example, a holder for holding the light source and a mirror are held. A holder, a light source code, sensors for detecting the size of originals, open / close detection, etc. are included.By cooling these components, the components are heated, deformed,
It is possible to prevent alteration, characteristic changes, and unstable image quality.

According to a seventh aspect of the present invention, at least one of the component, the reflecting mirror or the photoreceptor has a member formed of resin, and the component, the reflecting mirror or the photoreceptor is directly cooled. , It can be made of resin, and even if it is made of this resin, it is possible to prevent heating, deformation, alteration, and characteristic changes, the image quality is stabilized, and the parts are made of resin to reduce the weight. It enables high speed reading.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a document reading device.

FIG. 2 is a perspective view showing a state in which a document cover of the document reading device is opened.

FIG. 3 is a plan view of a document reading device with a document cover removed.

FIG. 4 is a diagram showing an embodiment in which a cooling condenser is arranged on the air intake side of an air duct of the document reading apparatus.

FIG. 5 is a schematic configuration diagram of a document reading device.

FIG. 6 is a principle view of a cooling device using adiabatic expansion.

FIG. 7 is a schematic configuration diagram of a document reading device.

FIG. 8 is a diagram showing cooling of the first mirror unit by a heat pipe.

FIG. 9 is a diagram showing cooling of a second mirror unit, a projection lens, a reflection mirror, and an image sensor by a heat pipe.

FIG. 10 is a schematic configuration diagram of a document reading device.

FIG. 11 is a principle view of a cooling device using a thermoelectric element.

FIG. 12 is a perspective view of a document reading device.

FIG. 13 is a schematic configuration diagram of a document reading device.

FIG. 14 is an enlarged cross-sectional view of a mounting portion of a document placing glass.

FIG. 15 is an enlarged cross-sectional view of a drive unit.

FIG. 16 is a diagram showing an example of a first mirror unit.

FIG. 17 is a diagram showing another example of the first mirror unit.

FIG. 18 is a diagram showing an example of a protection filter unit.

FIG. 19 is a diagram illustrating load deformation of polyethylene terephthalate (PET).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original reading device 2 Original placing glass 5 Exposure optical system 5a First mirror unit 5b Second mirror unit 5c Projection lens 5d Reflecting mirror 6 Imaging device 9a Pump 9b Air duct 9c Air intake port 10 Thermostat L Exposure lamp M1 Concave mirror M2 Reflecting mirror M3 reflecting mirror M4 reflecting mirror

Claims (7)

[Claims] At least a document table supporting a document, a light source and a reflecting mirror facing the document table to illuminate the document, and a reflected light reflected from the document illuminated by the light source. At least one photoreceptor,
It has an optical component for collecting or guiding the reflected light to the photoreceptor, and a temperature maintaining means for directly maintaining the temperature of at least one of the component, the reflecting mirror and the photoreceptor. An original reading device characterized by the above. 2. The temperature maintaining means controls the temperature of at least one of the component, the reflecting mirror, and the photoreceptor.
The original reading device according to claim 1, wherein the original reading device is maintained at 50 ° C or lower. 3. The temperature maintaining means maintains a temperature difference between the temperature of at least one of the component, the reflecting mirror or the photoreceptor and the temperature of outside air at 50 ° C. or less. The document reading device according to item 1. 4. The temperature maintaining means is a cooling means for directly cooling at least one of the component, the reflecting mirror, and the photoreceptor, according to any one of claims 1 to 3. The document reading device according to item 1. 5. The temperature maintaining means is an adiabatic means for directly blocking heat transfer to at least one of the component, the reflecting mirror and the photoreceptor. 3. The document reading device according to any one of 3 above. 6. The component according to claim 1, wherein the constituent parts are constituent parts of an original reading device excluding the light source, the reflecting mirror and the photoreceptor. Document reader. 7. The document according to claim 1, wherein at least one of the component, the reflecting mirror and the photoreceptor has a member formed of resin. Reader.