JP2005074978A - Heat radiation structure for laser light scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the temperature adjustment effect in a laser light scanner by enabling the effective radiation of the heat of the heat radiation fins of the housing in the laser light scanner. <P>SOLUTION: The heat radiation structure for a laser light scanner has in the housing a laser light generating means for generating a beam-like laser light, a scanning means for guiding to scan the laser light generated by the laser light generating means to a irradiation object surface and heat radiation fins on the outer surface of the housing, allowing the heat generated by the laser light generating means to be transmitted to the heat radiation fins for radiation. As a heat radiation means, a ventilation duct with the heat radiation fins facing the ventilation path is provided, and the ventilation duct is provided with an opening part for taking in the outside air into the ventilation duct and with a fan for discharging only the air inside of the ventilation duct. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure for effectively radiating heat generated by a laser beam scanning device that irradiates a surface to be irradiated with laser light.

Conventionally, as a laser beam scanning device, for example, an image of a photographic film such as a negative film or a positive film, or image data shot with a digital camera and stored in an IC card (memory card) is formed on a photographic photosensitive material. Laser beam scanning devices are known.
This laser beam scanning device includes a laser beam generator that generates R (red), G (green), and B (blue) laser beams in a beam shape, and R, G, and B generated by the laser beam generator. Main scanning provided with a laser intensity modulating member that modulates the laser light of each color in accordance with image data of each color, and a polygon mirror that scans the modulated laser light (referred to as modulated light) on the photosensitive material surface in the main scanning direction. By providing a mechanism and a transport mechanism for transporting the photosensitive material in the sub-scanning direction, a two-dimensional color image can be formed on the surface of the photosensitive material.
The laser light generator includes a red light source unit, a green light source unit, and a blue light source unit in order to generate R, G, and B laser beams.
The laser beam scanning device is incorporated in, for example, a photographic processing device.

  The laser light emitting diode used in the laser light generating section has a characteristic that the wavelength of the laser light changes according to a temperature change, but if the wavelength of the laser light is unstable, the image of the image formed on the photosensitive material Since the image quality deteriorates, the temperature of the laser beam generator is adjusted in order to keep the wavelength of the laser beam constant in the laser beam generator.

In particular, since a red laser light emitting diode is easily affected by temperature, a temperature adjusting means is provided by a Peltier element arranged near the red laser light emitting diode.
As described above, when the temperature adjusting means using the Peltier element is provided, the temperature of the electrode on the heat dissipation side of the Peltier element rises. Therefore, in order to dissipate this heat to the outside of the casing, heat is dissipated on the outer surface of the casing. Fins are formed.
In addition, in order to cool a motor and a driving semiconductor for driving a polygon mirror of a laser beam scanning apparatus, a scanning apparatus having a duct and a fan has been proposed. (See Patent Document 1.)

Japanese Patent Laid-Open No. 11-52267

However, the technique described in Patent Document 1 is for cooling a motor for driving a polygon mirror and a driving semiconductor, and effectively adjusts the temperature of a laser light source for forming a color image. Not for doing.
The heat of the laser light source is transmitted to the heat radiating fins, but the heat radiating from the heat radiating fins is insufficient and not effective. The reason is that the heat of the radiating fin is radiated by the air inside the photographic processing apparatus or the like in which the laser beam scanning device is incorporated, but the air inside the photographic processing apparatus or the like is This is because it becomes warm due to the heat of other components and the like, and since there is little temperature difference with the radiation fins, effective heat radiation cannot be performed.
Therefore, for example, when the temperature of the air inside the photographic processing apparatus or the like is high, the temperature adjustment of the laser light source by the Peltier element is not sufficiently effective, so the temperature of the laser light source is controlled to a low target temperature. It was difficult. Thus, there has been a problem that unless the temperature of the laser light source can be lowered, the life of the laser light source cannot be extended.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to improve the temperature adjustment effect in a laser beam scanning device by effectively discharging the heat of a radiating fin.

The heat radiation structure of the laser beam scanning device according to claim 1 according to the present invention includes:
In the housing, there are provided laser light generating means for generating beam-shaped laser light, and scanning means for guiding the laser light generated by the laser light generating means to an irradiation target surface for scanning. In the heat radiation structure of the laser beam scanning device configured to dissipate heat by providing heat radiation fins on the outer surface of the body and transmitting the heat generated by the laser light generation means to the heat radiation fins,
A ventilation duct having the heat radiating fins facing the ventilation path is provided, and the ventilation duct has an opening for taking outside air into the ventilation duct and a fan for exhausting only air inside the ventilation duct. We took measures to provide it.

In the present invention, since the heat radiating fins formed on the outer surface of the housing face the air passage in the air duct, the heat radiating fins are effectively radiated by the airflow flowing through the air passage inside the air duct. Therefore, since the temperature of the laser light source can be kept low, the life of the laser light source can be extended.
Further, the fan does not need to exhaust excess air other than the ventilation duct, and only the air inside the ventilation duct needs to be exhausted. Therefore, the capacity of the fan can be reduced and the cost can be reduced.

Hereinafter, a heat radiation structure of a laser beam scanning device according to the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 is a diagram showing a configuration example of a photographic processing apparatus that employs a heat radiation structure of a laser beam scanning apparatus according to the present invention.

First, an overall outline of the photo processing apparatus will be described.
The photo processing apparatus 1 uses images such as image data read from a film (negative, positive) by a line CCD scanner, image data taken by a digital camera, and image data created by a personal computer on a photosensitive material (printing paper). A laser beam scanning device 100 to be exposed, a photosensitive material storage unit 200 that stores photographic paper wound in a roll shape, cuts it to a predetermined size, and supplies it to the laser beam scanning device 100 as an exposure unit, and laser beam scanning The image forming apparatus 100 includes a developing unit 300 that develops, bleach-fixes, and stabilizes the photographic paper exposed by the apparatus 100, and a drying unit 400 that dries the photographic paper that has been stably processed.
In addition, a ventilation duct 550 having a heat dissipation structure according to the present invention is disposed below the laser beam scanning apparatus 100, and a louver 111 having a heat dissipation structure according to the present invention is provided at the front door 11 of the photographic processing apparatus 1. Is formed.

  The photosensitive material storage unit 200 is provided at, for example, the lower portion of the laser beam scanning device 100, and stores a photographic paper magazine 201 built therein so as not to expose the photographic paper wound in a roll shape. Inside the opening of the door 202, there are provided support rails (not shown) that can be pulled out to place the photographic paper magazine 201 and store it in the photosensitive material storage unit 200. When the photographic paper magazine 201 is loaded in the photosensitive material storage unit 200, the photographic paper is fed out from the photographic paper magazine 201, cut into a predetermined size by a cutter (not shown), and then conveyed to the laser beam scanning device 100. The

  The laser beam scanning device 100 will be described in detail later. The laser beam generation unit 104, a laser intensity modulation member 108 that modulates the intensity of the laser beam generated by the laser beam generation unit 104, and these components are shielded from light. And at least a housing 102 for storing in a state.

The photographic paper 2 developed, bleach-fixed, and stabilized by the developing unit 300 is conveyed to the drying unit 400, dried, and then discharged onto the first conveying belt 402 from the discharge port 401 at the top of the drying unit 400. Is done.
On the first conveyor belt 402, for example, photographic papers 2 for the number of frames photographed on one film are stacked. Then, the photographic paper 2 is transferred onto the second conveyor belt 403 by the first conveyor belt 402 and held on the second conveyor belt 403.
Each time the second conveyor belt 403 is transferred from the first conveyor belt 402, the second conveyor belt 403 is advanced by a predetermined length, so that photographs (dried photographic paper) for a plurality of films can be placed.

Next, the structure of the laser beam scanning apparatus 100, which is a main part of the photographic processing apparatus 1, will be described.
FIG. 2 is a plan view for explaining the structure of the laser beam scanning device 100. Note that in FIG. 2, the upper portion of the housing 102 is omitted, but a darkroom is provided so that external light does not enter the housing 102 and a laser beam does not leak from the housing 102 to the outside. And is sealed so that dust does not enter.

The laser beam scanning apparatus 100 includes three laser light sources 104R, 104G, and 104B on a housing 102.
The laser light source 104 </ b> R including the red laser light emitting diode is covered with a cover 800. The cover 800 is provided with a hole 810 so as not to obstruct the optical path of the laser beam.
In the following, when R (red), G (green), and B (blue) of the laser light source 104 are described, they are 104R, 104G, and 104B. A description will be given.

  The laser light source 104R includes a laser light emitting diode (LD) 104XR that emits a laser beam (hereinafter referred to as an R laser beam) having an R (red) wavelength (for example, 685 nm). For example, the laser light source 104G emits a laser light emitting diode 104XG that emits a laser beam having a wavelength of 1064 nm (hereinafter referred to as a G laser beam) and a G laser beam emitted from the laser light emitting diode 104XG at a wavelength of G (green). It comprises a wavelength conversion element (SHG) 104YG that converts the laser beam to a certain half wavelength (for example, 532 nm). The oscillation wavelength of the laser light emitting diode 104XG is determined so that a 532 nm laser beam is emitted from the wavelength conversion element. Similarly, the laser light source 104B, for example, emits a laser beam having a wavelength of 946 nm (hereinafter referred to as a B laser beam) and a B laser beam emitted from the laser light emitting diode 104XB to B (blue). And a wavelength conversion element 104YB that converts the laser beam into a laser beam having a half wavelength (for example, 473 nm). The oscillation wavelength of the laser light emitting diode 104XB is determined so that a laser beam of 473 nm is emitted from the wavelength conversion element 104YB.

  On the laser emission side of the laser light sources 104R, 104G, and 104B, an acousto-optic modulator (Acousto-Optic Modulator, hereinafter simply referred to as AOM) 108 that functions as a laser intensity modulation member, and a mirror 110 are sequentially arranged. A polygon mirror 118 is disposed on the laser reflection side.

  A lens group including an fθ lens 120 and a cylindrical lens 122 is disposed on the laser emission side of the polygon mirror 118. The photographic paper 2 that has been conveyed is irradiated with the R, G, and B laser beams that have passed through the lens group, and image exposure is performed.

  Next, the AOM 108 will be described. Three AOMs 108 are arranged at required positions of the housing 102 so that the laser beams incident from the laser light sources 104R, 104G, and 104B pass through the acoustooptic medium inside the AOM 108, and each AOM 108 has an AOM driver (see FIG. Abbreviation).

  When a signal corresponding to the R, G, and B density of an image (output for each of R, G, and B) is input from the AOM driver to each AOM 108, an ultrasonic wave corresponding to the output of the AOM driver is input to the acoustooptic medium of the AOM 108. Diffraction occurs due to the optical effect, and the laser beam incident on the AOM 108 has an intensity corresponding to the density of the image, is emitted from the AOM 108 as diffracted light (modulated light), reaches the photosensitive material 2, and forms an image.

Next, the operation of the laser beam scanning apparatus 100 configured as described above will be described.
The laser beam emitted from the laser light source 104 enters the AOM 108. Note that the red laser light emitted from the laser light source 104 </ b> R having the red laser light emitting diode enters the AOM 108 through the hole 810 provided in the cover 800.
A signal corresponding to the R, G, B density of the image is input from the AOM driver to the AOM 108, and the laser beam incident on the AOM 108 has an intensity corresponding to the density of the image and is emitted as diffracted light (modulated light). . The laser beam emitted from the AOM 108 is reflected by the polygon mirror 118 rotating at a constant speed, scanned in the main scanning direction, and irradiated onto the photographic paper 2 through the fθ lens 120 and the cylindrical lens 122. On the other hand, the photographic paper 2 is conveyed by a conveyance unit (not shown) in a direction substantially orthogonal to the main scanning direction. As a result, an image is formed on the photographic paper 2.
Thus, the scanning of the laser beam by the rotation of the polygon mirror 118 has a function as a main scanning for forming a two-dimensional image, and the conveyance of the photographic paper 2 has a function as a sub scanning. .
The polygon mirror 118 has a configuration corresponding to the scanning means described in the claims.

Next, temperature adjusting means in the laser beam scanning device 100 will be described.
FIG. 3 is a side sectional view showing the detailed structure of the laser light source 104R for red laser light constituting the laser light scanning device 100.
In FIG.
The laser light emitting diode (LD) 104XR is attached in close contact with a first heat transfer member 502 made of chromium copper alloy via a ceramic spacer 501.
One pole of a Peltier element 510 is attached in close contact with the first heat transfer member 502, and an aluminum second heat transfer member 503 is attached in close contact with the other pole of the Peltier element 510. Yes. The second heat transfer member 503 is attached in close contact with the casing 102 made of metal such as aluminum die-cast via a third heat transfer member 504 made of aluminum.
A temperature sensor 520 is disposed in the vicinity of the laser light emitting diode (LD) 104XR. The temperature sensor 520 is thermally coupled as closely as possible to the laser light emitting diode (LD) 104XR.

The ceramic spacer 501 is a material having electrical insulation and excellent thermal conductivity.
The laser light emitting diode (LD) 104XR is attached to a substrate 505 provided with a necessary drive circuit. A ceramic member 506 having electrical insulation and thermal insulation is interposed between the first heat transfer member 502 and the third heat transfer member 504.
Thus, the laser light emitting diode (LD) 104XR is thermally coupled to one pole of the Peltier element 510 via the ceramic spacer 501 and the first heat transfer member 502, and the other of the Peltier element 510 is The poles are thermally coupled to the housing 102 and the radiation fins 530 formed on the housing 102 via the second heat transfer member 503 and the third heat transfer member 504.

The red laser light source 104 </ b> R configured as described above is covered with a cover 800. A hole 810 is provided on the optical path of the laser light emitted from the cover 800 so as not to disturb the laser light.
With the above configuration, the laser light emitted from the laser light emitting diode (LD) 104XR is emitted through the lens system 507, passes through the hole 810 provided in the cover 800, and enters the optical system such as the AOM 108. .
The cover 800 surrounds at least the laser light emitting diode (LD) 104XR, the Peltier element 510, and the temperature sensor 520 in the same space, and air flows between the internal space and the external space. Or it is provided with a material and a structure capable of suppressing convection.
Instead of the hole 810, a laser beam transmitting portion may be formed by a member that transmits laser beam, such as a lens or glass.

  As described above, the cover 800 surrounds at least the laser light emitting diode (LD) 104XR, the Peltier element 510, and the temperature sensor 520 in the same space. The temperature of the internal space is detected without being affected by the environmental temperature, and only the internal space of the cover 800 is efficiently heated or cooled by the Peltier element 510. Therefore, the temperature of the laser light emitting diode (LD) 104XR disposed in the temperature-controlled space is accurately adjusted to the target temperature.

In addition to the temperature adjustment of the laser light source by the temperature sensor 520, the overall temperature adjustment of the internal space of the laser beam scanning apparatus 100 is also performed. Conventionally, these two systems of temperature adjustment are completely individual. Were controlled independently. For this reason, when a large temperature difference occurs between the temperature of the laser light source and the temperature of the internal space of the laser beam scanning device 100 that is the surrounding space, the dissimilar materials such as metal and resin that constitute the laser light source are used. Since the degree of expansion changes, the laser optical axis may shift.
In the laser beam scanning device 100, the temperature adjustment of the laser light source by the temperature sensor 520 and the Peltier element 510 and the temperature adjustment of the internal space of the laser beam scanning device 100 are associated and controlled.

In other words, for example, it is preferable to set the target temperature for adjusting the temperature of the laser light source and the target temperature for adjusting the temperature of the internal space of the laser beam scanning device 100 to a close temperature. Alternatively, in one temperature adjustment, it is preferable to control so as not to generate a large temperature difference while monitoring the other temperature.
As described above, the temperature adjustment of the laser light source and the temperature adjustment of the internal space of the laser beam scanning apparatus 100 are controlled in association with each other so that a large temperature difference does not occur. It is also possible to prevent the laser optical axis from shifting.

Next, details of the heat dissipation structure, which is a feature of the present invention, will be described.
As shown in FIGS. 4A, 4 </ b> B, and 4 </ b> C, heat radiating fins 530 are formed on the lower outer surface of the casing 102. The heat dissipating fins 530 are made of aluminum die-cast as in the case 102, and a plurality of plate-like ridges are formed in rows. Around these radiating fins 530, ribs 540 having substantially the same height as the radiating fins are formed and arranged so as to surround all the radiating fins 530.
These heat radiation fins 530 are formed in a region including the back side of the region where the three color laser light sources 104R, 104B, and 104G are disposed.
Therefore, the heat of the laser light source that generates a large amount of heat is effectively transmitted to the heat radiating fins.

As shown in FIGS. 5A and 5B, the space including the heat radiating fins 530 surrounded by the ribs 540 communicates with the air duct 550, and the heat radiating fins 530 are ventilated inside the air duct. The road is in the desired state.
The ventilation duct 550 is surrounded by the opening 551 for taking in outside air from the outside of the casing, the introduction portion 552 for introducing outside air from the opening 551 to the space surrounded by the rib 540, and the rib 540. A fin cover portion 553 that covers the ventilation cross-sectional area of the space to be narrow, and a discharge portion 554 that discharges air that has passed through the vicinity of the heat dissipating fins 530 and received heat. Two exhaust fans 560 are disposed in the discharge portion 554, and are configured to generate an air flow flowing in from the opening portion 551 by discharging air inside the ventilation duct 550.

Since the exhaust fan 560 has a small diameter, the exhaust fan 560 is arranged in two so as to be efficiently accommodated in the ventilation duct 550 having a rectangular cross-sectional shape.
The opening 551 is disposed at a position corresponding to the louver 111 formed on the door 11 provided on the front surface of the photographic processing apparatus 1.
With such a configuration, the outside air taken in from the louver 111 of the door 11 provided on the front surface of the photographic processing apparatus 1 is introduced into the ventilation duct 550 from the opening and flows between the radiation fins 530 to dissipate heat. The heat of the fins is taken away and exhausted by the exhaust fan 560.
Note that the heat dissipation fin 5 530, the ventilation duct 550, and the exhaust fan 560 constitute a heat dissipation structure 5. The heat dissipation structure 5 corresponds to the heat dissipation structure of the laser beam scanning device described in the claims.

Next, a specific detailed structure of the heat dissipation structure according to the present invention will be described.
First, with respect to the ventilation duct, by reducing the cross-sectional area in the vicinity of the heat radiating fins from the cross-sectional area of the introduction part 552 and the exhaust part 554 of the air duct 550, the flow velocity of air in the vicinity of the radiating fins is increased. Increased heat dissipation effect by fins.
In addition, the contact portion between the rib 540 and the fin cover portion 553 of the ventilation duct 550 is in close contact with each other so that there is no air leakage or the like and only the portion surrounded by the rib 540 can be exhausted. It has become. For example, as shown in a partial cross section in FIG. 6, a groove 555 having a concave cross section is provided on the ventilation duct 550 side, and a packing 556 such as a cushion material is attached to the bottom of the groove 555, and the end of the rib 540 is provided. It is good to comprise so that the said packing 556 may be pressed by a part.

Further, the contact portion between the opening 551 of the ventilation duct and the door 11 has a structure that is in close contact with each other so as not to leak light or air. For example, as shown in a partial cross section in FIG. 7, a groove 112 having a concave cross section is provided inside the door 11, and a packing 113 such as a light-shielding cushioning material is attached to the bottom of the groove 112. It is good to comprise so that the said packing 113 may be pressed in the edge part of the opening part 551. FIG.
And since the circumference | surroundings of the louver 111 formed in the said door 11 are surrounded by the said concave groove | channel 112, in the state which closed the door, the light which leaks in the ventilation duct from the said louver 111, the exterior of a ventilation duct, That is, leaking into the photographic processing apparatus 1 is prevented. Further, since air leakage is also prevented, only the outside air that has passed through the slit of the louver 111 is taken into the ventilation duct.

Next, the operation and effect of the heat dissipation structure according to the present invention will be described.
The Peltier element 510 moves excessive heat in the laser light emitting diode (LD) 104XR to the radiation fins 530 by a temperature adjustment circuit (not shown). Then, since the heat of the radiating fin 530 is taken away by the air flowing through the ventilation duct, the temperature adjustment of the laser light source by the Peltier element 510 is effectively performed.
Therefore, for example, when the ambient temperature is high and the target temperature for temperature adjustment is low, the temperature adjustment of the laser light source by the Peltier element 510 is not effective with the conventional radiating fin alone, and the target temperature is controlled to a low target temperature. However, since the heat of the radiating fin is forcibly radiated by the air flow flowing through the ventilation duct, the temperature of the laser light source can be effectively adjusted by the Peltier element 510, and the target temperature is sufficiently low. Can be controlled.
In this way, the temperature of the laser light source can be adjusted to a low temperature, so that the lifetime of the laser light emitting diode can be extended.

  Furthermore, since the exhaust fan only needs to exhaust the air inside the ventilation duct, there is no waste as in the conventional case, and a small fan can be employed. Therefore, the cost of the exhaust fan can be reduced as compared with the prior art.

It is a figure which shows one structural example of the photographic processing apparatus in which the laser beam scanning apparatus of this invention is used. It is a top view explaining the structure of a laser beam scanning apparatus. It is a partial cross section side view which shows the structure around a laser light emitting diode. It is a schematic side view of the housing | casing of a laser beam scanning apparatus. 4A is a bottom view of the laser beam scanning device, FIG. 4B is a partial cross-sectional view along line XX, and FIG. 4C is a partial cross-sectional view along line YY. FIG. It is the schematic of the state which attached the ventilation duct to the housing | casing of a laser beam scanning apparatus. FIG. 5A is a cross-sectional view of the main part, and FIG. 5B is a bottom view thereof. It is an expanded sectional view of the principal part of the contact part with the rib of the housing | casing of a laser beam scanning apparatus, and a ventilation duct. It is an expanded sectional view of the principal part of the contact part of the door of a photographic processing apparatus, and the opening part of a ventilation duct.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photo processing apparatus 100 Laser beam scanning apparatus 104 Laser light source (laser beam generation means)
102 Housing 118 Polygon mirror, scanning means 5 Radiation structure 530 of laser beam scanning device Radiation fin 550 Ventilation duct 551 Opening 560 Exhaust fan

Claims (1)

In the housing, there are provided laser light generating means for generating beam-shaped laser light, and scanning means for guiding the laser light generated by the laser light generating means to an irradiation target surface for scanning. In the heat radiation structure of the laser beam scanning device configured to dissipate heat by providing heat radiation fins on the outer surface of the body and transmitting the heat generated by the laser light generation means to the heat radiation fins,
A ventilation duct having the heat radiating fins facing the ventilation path is provided, and the ventilation duct has an opening for taking outside air into the ventilation duct and a fan for exhausting only air inside the ventilation duct. A heat dissipating structure for a laser beam scanning device, comprising: