JP2001063136A - Optical head and optical printer having it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent emission efficiency from lowering while reducing power consumption. SOLUTION: The optical head 14 for use in a printer comprises a printed board 50 mounting a plurality of light sources S, an aperture plate 80 disposed on the side of the printed board facing a sheet, a Peltier element 60 disposed to touch the printed board 50 thermally at a cooling side part 62, and a heating section 71 disposed to touch a heat dissipation side part 63 of the Peltier element 60 thermally. The heating section 71 has a roller 72 for heating the sheet by rolling on the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical head for recording pattern information on a medium by emitting pattern information in the form of an optical signal.
For example, the present invention relates to a color exposure head suitable for forming a photosensitive latent image on a photosensitive pressure-sensitive color print sheet and a color printer using the same.

[0002]

2. Description of the Related Art A plurality of light sources composed of LED (light emitting diode) chips are mounted on the surface of a printed circuit board at intervals, and an aperture plate provided with an aperture for narrowing light from each light source is mounted on the front surface of the printed circuit board. An exposure head for a printer which is fixed at a distance from a light source is known. The LED emits light in response to an image signal, and the light narrowed down by the aperture is irradiated on the photosensitive printing paper to form a photosensitive latent image on the printing paper.

[0003]

However, in this type of exposure head, a part of the energy consumed by the LED is converted into heat, which may cause the exposure head to be heated. The luminous efficiency of the LED significantly decreases depending on the temperature of the element. For example, in a GaP red LED, when heated from a room temperature level of 20 ° C. to 80 ° C., the luminance is reduced to about 50%. For this reason, there is a possibility that an appropriate exposure amount cannot be obtained, or that a drive current is increased to obtain an appropriate exposure amount, and that luminous efficiency is further reduced. In the worst case, there is a possibility that the LED element itself may be destroyed.

In order to radiate the heat generated from the exposure head, for example, a radiator is provided on a carriage to which the exposure head is attached, and further, the heat of the carriage is transmitted to a carriage guide to radiate the heat. It was due to natural radiation into the air, natural heat transfer to other objects, and had insufficient power to cool the exposure head. In addition, since temperature control cannot be performed with natural heat radiation, the temperature of the exposure head also fluctuates depending on the temperature of the outside world,
For this reason, the luminance also fluctuated, and the image quality could not be kept constant. The radiated heat was merely wasted to the outside world and was not actively used. For example, a printer using photosensitive pressure-sensitive print paper requires a fixing heater for promoting a development reaction after pressure development. This is provided irrespective of the heat generated by the exposure head, and the printer as a whole generates a considerable amount of heat and thus consumes a large amount of power.

The present invention has been made in view of the above points, and has as its object to provide an optical head capable of actively cooling a light source and thus maintaining a high luminous efficiency, and an optical head having the same. An object of the present invention is to provide a printer using an optical head. It is another object of the present invention to provide a printer using an optical head that can divert generated heat to another purpose in the printer, and thus can increase energy use efficiency.

[0006]

According to the present invention, there is provided an optical head comprising: a light source for forming a latent image on a photosensitive medium by exposing the photosensitive medium to light; A Peltier element arranged with conductivity,
The light source is cooled by the Peltier element.

In the optical head of the present invention, since the light source can be actively cooled by the Peltier element, the light emission efficiency of the light source does not decrease. To configure the optical head more specifically, a light source that forms a latent image on the photosensitive medium by exposing the photosensitive medium, a printed circuit board on which the light source is mounted, and a cooling-side portion of the substrate are provided. A Peltier element arranged with thermal conductivity, and radiating means arranged with thermal conductivity at a portion on the heat radiation side of the Peltier element, The light source is configured to be cooled.

In this case, the heat generated by the light source is conducted to the printed circuit board, but the printed circuit board is disposed on the cooling side of the Peltier element with thermal conductivity, so that the Peltier element is driven. This cools the printed circuit board and thus the light source. Further, since the heat radiating means is disposed on the heat radiating side of the Peltier element with thermal conductivity, the heat generated by the light source and the heat generated by the Peltier element are radiated to the outside from the heat radiating means.

Although the cooling capacity of the Peltier element may be constant, the cooling capacity of the Peltier element may be varied in accordance with the amount of heat generated by the light source. In this case, a Peltier element drive control means is provided. . Further, in the present invention, the optical head is provided as an exposure head for printing to constitute an optical printer. In the configuration of the optical printer, the heat radiating means may be arranged so that the heat radiating surface faces the photosensitive medium and the photosensitive medium is heated. In the case of a printer using a photosensitive pressure-sensitive medium, pressure developing means for developing a latent image formed on the photosensitive medium by pressing the photosensitive medium downstream of the exposure head in the feeding direction of the photosensitive medium. Is provided. At this time, the heat dissipating means is disposed downstream of the pressure developing means in the feeding direction of the photosensitive medium, with its heat dissipating surface facing the photosensitive medium and heating the photosensitive medium.

[0010] In some cases, the printing paper is heated in a fixing process for accelerating the development reaction after the pressure development. In this printer, the heat generated by the exposure head is used to heat the photosensitive medium by the heat radiating means. . Accordingly, the fixing heater provided in the conventional printer is not required, and the power consumed by the heater is not required, so that the power consumption of the printer can be reduced.

It is preferable that the heat radiating means is configured to heat the photosensitive medium by rolling on the photosensitive medium. Further, in order to use the heating before the exposure in place of the heating in the fixing process, the heat-dissipating surface of the exposure head faces the photosensitive medium on the upstream side in the feeding direction of the photosensitive medium. It may be arranged to be heated. It is clear that the power consumption of the printer can be reduced even in this case.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a printer having an optical head according to a preferred embodiment of the present invention will be described with reference to a preferred embodiment shown in the accompanying drawings.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) First, a preferred example of a photosensitive / pressure-sensitive print sheet 1 used in the printer 10 shown in FIG. 6 will be described with reference to FIG. In this example, the photosensitive / pressure-sensitive print paper 1 is coated with photosensitive / pressure-sensitive microcapsules, and can be printed by an exposure operation (latent image forming operation) by an exposure head and a pressure development operation by a pressure development head. Refers to a sheet. The sheet material may have any three-dimensional shape as long as it has a width, a length, and a thickness such that the sheet material can be intermittently fed in the sheet feeding direction at the time of printing (printing). The print paper 1 is, for example, as shown in FIG.
A sheet-like base (base) 2 made of ET (polyethylene terephthalate), an image receiving layer 3 formed on the sheet-like base 2 and containing a color developer, and a photosensitive / pressure-sensitive microcapsule are formed of a binder (adhesive). ) Comprises a photosensitive / pressure-sensitive microcapsule layer 4 uniformly dispersed on the image receiving layer 3 and a protective layer 5 such as transparent PET. The substrate or substrate 2 of the sheet may be another material such as paper instead of a plastic material. The microcapsule layer 4 does not need to have a binder, and the image receiving layer 3 and the microcapsule layer 4 may be a single mixed layer. The paper 1 having the above-described laminated structure is typically 0.1 mm
Of the order of

The light-sensitive and pressure-sensitive microcapsules have a transparent outer capsule wall made of gelatin or the like and having a diameter of about several microns. A color-forming substance that contacts the developer of the image receiving layer 3 to form a color when the capsule that has not been crushed is crushed is enclosed. Typically, each microcapsule includes a color-forming substance that develops into one of the three primary colors of the paint when contacted with a developer, and a color that is actually complementary to the color developed by the color-forming substance ( A light-curing substance that cures with light of the three primary colors of light is enclosed together. That is, there are three types of microcapsules, each of which selectively absorbs a red (magenta) magenta (M) color-forming substance and a green light (G) complementary thereto. Type M microcapsules enclosing a photocurable substance that cures by curing, yellow (Y) exhibiting yellow
Y type microcapsules enclosing a color-forming substance for use and a photo-curing substance that cures with blue light (B), and a color-forming substance for cyan (C) and a red light (R) exhibiting a blue (blue-violet) color. Type C encapsulating a photocurable substance that cures
Of microcapsules. In the microcapsule layer 4, these three types of microcapsules are uniformly dispersed and applied.

For example, when performing color printing on print paper at 300 dpi, one dot is formed in an area having a diameter of about 85 μm. When the dot area is irradiated with, for example, red light from the exposure head, the photocurable substance in the type C microcapsules is cured, but the photocurable substance in the type M and Y microcapsules is not cured. A red latent image is formed in this dot area. When this dot area is placed under pressure, the cured type C microcapsules are kept as they are, but the uncured type M and Y microcapsules are crushed,
Each color-forming substance reacts with the color developer in the image receiving layer 3 to exhibit a purple-red color and a yellow color, and exhibit a substantially red color as a whole. The degree to which the type C microcapsules are cured depends on the intensity (light amount) of light applied to the dot area, and depending on the degree, the type C microcapsules are slightly crushed or not crushed at all. Thus, the degree of mixing of blue in the dot area changes. Therefore, the degree of hardening of the three types of microcapsules differs depending on the color of the irradiation light, and the color developed by the crushing of the microcapsules differs.

The microcapsules are, as described above, instead of being composed of three types M, Y, and C capable of developing a color according to each of the three wavelengths of light corresponding to the three primary colors of light, or one or more. Two or more one or two that enable color development in response to light in any particular wavelength range,
Or it may be of any number of types greater than that. Each type of microcapsule is typically
Although the microcapsules are uniformly distributed on the application surface of the paper 1, the distribution of the microcapsules may be different depending on the area of the paper 1 in some cases.

Next, the configuration of the printer 10 will be described. In the printer 10 of FIG. 6, the print paper 1 is fixed at a constant pitch in the Z direction by paper feed mechanisms 12, 13 such as upstream and downstream rollers supported between the side walls 11a, 11b of the frame 11 of the printer 10. While the sheet 1 is intermittently fed at the sheet feed pitch Q and the feeding of the sheet 1 in the sheet feeding direction Z is stopped, the carriage 16 on which the exposure head 14 and the pressure developing head 15 are mounted is guided by a guide such as a guide rail. Scanning is performed in the scanning direction X perpendicular to the sheet feeding direction Z along the mechanism 17.

The reciprocating movement or scanning of the carriage 16 is performed, for example, by circulating a timing belt around timing pulleys provided at both ends in the scanning direction X, and fixing the timing belt to a slot formed in the carriage 16 in the sheet feeding direction. This is done by engaging the pins.
Instead, the shaft is extended in the scanning direction so as to be rotatable around its axis, and an engaging pin integrally formed on the carriage 16 is engaged with a bidirectional spiral groove formed on the outer periphery of the shaft. The carriage 16 may be reciprocated or scanned by rotating the shaft in one direction, or by other means.

In FIG. 6, reference numeral 18 denotes a scale read from a scale 19, and the exposure head 1 is controlled under the control of a controller 20.
X-direction scanning position sensor for detecting the X-direction position of 4, 21
Is an X-direction drive mechanism for driving the carriage 16 in the X direction (X1, X2 directions), 22 is a Z-direction drive mechanism for intermittently moving the paper 1 in the Z direction via the paper feed mechanisms 12, 13, and 23 is power transmission. Each drive mechanism 21, including the mechanism
2 is a driving source for driving the driving device 2.

Image information or the like to be printed is provided to the controller 20 of the printer 10 from an image information processing apparatus such as a digital camera or a print pattern information source 24 such as an image information recording medium. The controller 20 including a microprocessor drives the exposure head driving device 25 at each paper feed position Z based on the pattern information from the print pattern information source 24 and the X-direction position data from the scanning position sensor 18 to drive the exposure head. 14
As a result, a dot-shaped latent image having a predetermined color and sensitivity (curing degree) is formed at positions x and z of the sheet 1. X of exposure head 14
A latent image is formed in the X direction with the directional scan, and X1 or X
Each time the scanning in the two directions is completed, the paper 1 is intermittently fed by one pitch in the Z direction, and then the scanning of the exposure head 14 in the X direction is repeated, so that the two-dimensional pattern is formed on the paper 1 in the XZ plane. A latent image such as a form image or a character is formed. The exposed area of the sheet 1 is pressed by a pressure developing head 15 which is located downstream of the exposure head 14 in the sheet feed direction Z and is moved in the X direction together with the exposure head 14 when the exposure head 14 scans in the X direction. The microcapsules are crushed according to the exposure (photosensitivity) state of each dot area, and development is performed.

As shown in FIG. 1, the exposure head 14 of the printer 10 includes an exposure unit 14a having a light source S and a heat radiation unit 14b for radiating heat generated by the exposure unit 14a. , A printed circuit board 50 on which the light source S is mounted, and an aperture plate 80 having an aperture opening. FIG. 3 is a plan view of the exposure unit 14a excluding the aperture plate 80. As shown in FIG. 3, the light source S is, in this example,
Two blue light sources Sb1 and Sb2 (blue light sources are generally denoted by a symbol Sb) and three red light sources Sr1 and Sr
2, green light sources Sg1 and Sg2 (green light sources are collectively represented by reference symbol Sg). And at a desired interval in the scanning direction X. R, G, B light sources Sr, Sg,
The number of Sb is the number of light sources necessary for printing at one point (dot area). If the intensity of light from the light source is higher, the number of light sources of each color may be smaller,
If the light intensity is weaker, the number of light sources may be increased.

Each light source is an LED emitting light of each color.
(Light emitting diode). Each light source may be another one such as a semiconductor laser or a plasma display tube instead of the LED. The type and number of colors to be emitted,
The number of light sources for each color can be appropriately selected according to the photosensitive characteristics of the printing paper and pattern information that may be printed.

As shown in FIGS. 3 and 5, the printed circuit board 50 includes a ceramic substrate main body 51, a connection pattern or wiring pattern 52 for the light source S formed on the substrate main body 51, and a wiring. Formed on the pattern,
Spacer plate 53 having a recess for accommodating each light source S
And The thickness of the spacer plate 53 is set to be large enough to accommodate the bonding wires that are spatially wired in addition to the thickness of the LED light source S.

As shown in FIGS. 4 and 5, the aperture plate 80 fixed on the spacer plate 53 is, for example, a thin metal plate having a thickness of about 0.05 mm.
A stop aperture A is provided at a position just facing the center of the ED light source S. That is, the aperture plate 80 is provided with the LED light source Sb.
1, Sb2, Sr1, Sr2, Sr3, Sg1, Sg2
Apertures or apertures Ab1, Ab2, Ar1, Ar2, Ar3, Ag
1 and Ag2 (collectively represented by the symbol A).
In the illustrated example, the aperture A is, for example, about 0.1 mm in diameter.
The circles have the same size of about 0.2 mm to 0.2 mm. The center position of the aperture opening A defines a representative position of the light source S in the scanning direction X of the light source and the sheet feeding direction Z.

The size and shape of the aperture opening A include the size and shape of a dot (a dot-like latent image in this example) to be formed on the paper 1, the size and shape of the light source S, and the light source S and the opening A. Is selected according to the distance between
It may be large or small, and may be an oval instead of a circle. For example, the size and shape of the opening may be different depending on the color of the light source, the size and shape of the opening may be different for each light source, and the size and shape of the opening may be different for some light sources. Further, in some cases, the position of the opening may be shifted in one or both of the X direction and the Z direction from the position just facing the center of the light source.

FIG. 2 is a sectional view of the exposure head 14 taken along the line II-II of FIG. In this figure, reference numeral 60 denotes a Peltier element. The Peltier element 60 connects a number of N-type thermoelectric material chips and P-type thermoelectric material chips 61 alternately in series, and among the joints, alternately arranged joints are formed on the first substrate, and the remaining joints are formed. The part is arranged on the second substrate. When an electric current is applied to the Peltier element 60 configured as described above, one of the first and second substrates absorbs heat and the other substrate generates heat.

In the exposure head 14 shown in FIG.
The heat absorbing side substrate 62 of the Peltier element 60 is arranged in contact with the printed circuit board 50 of 4a. Also, the heat generating side substrate 63
, A heat transfer section 70 is arranged in contact with the heat transfer section 70. Currently 1 /
As the Peltier element having a heat absorption of about 4 W, a sufficiently small Peltier element has been put into practical use. For example, there is a product of about 3 mm square and 0.36 W. Therefore, it is sufficiently possible to arrange the Peltier element on the back side of the exposure head in this way.

The heat transfer section 70 provided on the heat generating side substrate 63 side of the Peltier element 60 extends along the downstream Z direction in the sheet feeding direction, and is connected to the heating section 71 serving as the heat radiating section 14b on the downstream side. . The heating unit 71 includes a heating unit structure 75, a heating roller 72 supported by the heating unit structure 75, and a spring 73 that elastically supports the heating roller 72 on the heating unit structure 75. The heating roller 72 has shafts 72a on both end surfaces of the roller. The heating unit structure 75 has an elongated hole 76 into which the shaft 72a is inserted, and the heating roller 72 is supported so as to be movable in a direction perpendicular to the sheet. The spring 73 has a shaft 72a in the elongated hole.
The shaft 72a is urged so as to push the upper side downward in the paper direction. Reference numeral 74 denotes a pressure roller hole provided so that the pressure roller 30 of the pressure development head 15 penetrates as described later.

The exposure head 14 configured as described above
Is attached to the carriage 16 as shown in FIG. The exposure unit 14 a is arranged facing the print paper 1 placed on the exposure table 81. A heating unit 71 is arranged downstream of the heat transfer unit 70 in the sheet feeding direction Z, and the heating roller 72 rolls on the print sheet 1 placed on the heating table 82. . Hole 7 for pressure roller
4, the pressure roller 30 of the pressure development head 15 penetrates, projects toward the print paper 1 side, and presses it.

The exposure head 1 constructed as described above
In 4, when each LED constituting the light source S is driven,
The LED is heated with the light emission, and the printed circuit board 50 constituting the exposure unit 14a is heated. Therefore, a current is passed through the Peltier element 60 to
By cooling the heat absorption side substrate 62 that is in contact with 0, the exposure unit 14a can be cooled. The absorbed heat and the heat generated by the Peltier element 60 itself are radiated from the radiator 14b.

The Peltier element 60 can generate a constant cooling capacity by passing a constant current. However, it is preferable to provide a Peltier element driving circuit 26 and control the cooling capacity by using the circuit. . FIG.
, Information on the current flowing through the exposure unit 14a is input from the exposure head driving device 25 to the controller 20. The controller 20 performs current-voltage conversion of this current information, digitizes it with an A / D converter, and inputs it.
This current information is used as an index of the calorific value of the exposure unit 14a. The controller 20 controls the Peltier device driving circuit 26 based on the current information. The exposure unit 14a
When the current information is large, the Peltier element driving circuit 26 is instructed to supply a large current to the Peltier element 60. Therefore, the cooling capacity of the Peltier element 60 increases.
When the current information is small, a small current is supplied to the Peltier element 60 by instructing the Peltier element driving circuit 26 to be reversed. Therefore, the cooling capacity of the Peltier element 60 decreases. If the relationship between the consumed current of the exposure unit 14a and the amount of heat generated, and the relationship between the drive current of the Peltier element 60 and the cooling capacity are not linear, the controller 20 performs appropriate conversion for control.

The calorific value of the exposure unit 14a may be measured by another means. For example, a temperature may be directly measured by attaching a thermistor to the exposure unit 14a. As described above, the cooling capacity is controlled by controlling the current for driving the Peltier element 60 according to the measured temperature. By the way, after the photosensitive and pressure-sensitive print paper 1 is developed by pressure development, the print paper 1 is generally heated in order to promote a development reaction. This process is called a fixing process, and a conventional printer is provided with a fixing heater downstream of the pressure developing unit. In the printer according to the present invention, the heat radiating portion 14b is provided on the downstream side of the pressure developing head 15 as described above. The heating roller 72 forming the heat radiating portion 14b rolls on the print sheet 1 together with the carriage 16, and transfers the heat emitted by the Peltier element 60 onto the print sheet 1 to advance the fixing process.

When the amount of heat generated from the exposure head and the balance of the amount of heat required in the fixing process were measured, the results were as follows. First, the heat value of the LED was about 0.25 W.
On the other hand, assuming that the LED is heated by this heat generation and is cooled by the Peltier element, if the efficiency of the Peltier element is estimated to be about 40%, the heat generation on the heat generation substrate side is 0.25 / 0.4. * 2 = about 1.25W. This calorific value was found to be substantially equal to the calorific value required in the fixing process. Therefore, if the amount of heat generated by the exposure head is used for fixing by the Peltier element, the conventionally required fixing heater becomes unnecessary.

As described above, the fixing heater can be made unnecessary if the conditions are adjusted. However, if the amount of heat generated by the Peltier element is insufficient, a small-sized fixing heater may be provided. Even with such a configuration, the power consumption is increased only by the small-sized heater, so that it is clear that the power consumption is lower than that of the conventional printer. This small-scale fixing heater may be used as an auxiliary even when the LED has not yet generated heat, such as immediately after power-on.

The printing operation on the paper 1 by the printer 10 configured as described above will be briefly described with reference to FIG. When a print command is given to the printer 10 while the paper feed mechanisms 12 and 13 are stopped,
The X-direction drive mechanism 21 is driven by the drive source 23,
The scanning in the scanning direction X is started from the initial position on the carriage 16 on which the exposure head 14 and the pressure developing head 15 are mounted, and a scale read signal is sent from the exposure head position sensor 18 to the controller 20, and the exposure is performed by the controller 20. The information is decoded as position information of the head 14. The controller 20 determines the position of the exposure head 14 based on the position information of the exposure head 14 and the image information data (position and color data) from the pattern information source 24.
Is given to the exposure head 14 according to the scanning position of
If desired, the light source S of the exposure head 14 emits light at a predetermined intensity to form a latent image of a predetermined color at a predetermined position (dot area) in the scanning direction of the printing paper 1. This operation is continued until the exposure head 14 completes one-way scanning (forward scanning or backward scanning) from the initial position. Exposure head 1
At the point in time when the one-way scanning by the carriage 4 is completed, the pressure developing head 15 of the carriage 16 is in a state where the paper 1 can be fed in the Z direction, and the paper feed mechanisms 12 and 13 feed the paper 1 by one pitch (dot area). It is sent in the Z direction by Q) (for one row). After that, the same exposure operation and paper feeding operation are repeated until the exposure operation by the light source S for the last line of the pattern of one page of the paper 1 (the length in the Z direction is variable) is completed.

On the other hand, until the exposed area (latent image forming area) of the sheet 1 reaches the pressure development head 15, the pressure development scanning by the pressure development head 15 is practically invalid. When the exposure area of the sheet 1 reaches the pressure development head 15, the microcapsules corresponding to the latent image are crushed and collapsed at the time of the pressure development scan by the pressure development head 15 accompanying the scanning of the carriage 16 and the predetermined distance. The development that develops a color proceeds simultaneously. Further, when the pressurized development area of the sheet 1 reaches the heating section 71, the sheet 1 is heated by the heating roller 72 of the heating section 71, and the fixing process is accelerated. (Second Embodiment) In the first embodiment, the heating unit 71 has a roller structure. However, the heating unit 71 may have another structure. FIG. 8 is a sectional view of an exposure head according to a second embodiment in which the heating unit 71 has another configuration.

In this embodiment, in the heating section structure 75 of the heating section 71, a radiating fin 77 is provided on the surface of the heating sheet 71 with respect to the printing paper 1, and heat is transmitted from the fins 77 to the printing paper. Since the feeding speed of the paper in the Z direction is relatively slow,
If the length of the radiation fins 77 in the Z direction is increased to some extent as shown in the figure, a specific point on the printing paper can receive heat during the scanning of the exposure head 14 a plurality of times. Further, if the radiation fins 77 are provided in the scanning direction as shown in the drawing, air flows between the fins with the scanning, and the radiation fins 77 can be sufficiently cooled. When heat is not applied to the print paper, the heat radiation fins 77 may be provided on the side opposite to the print paper to increase the heat radiation efficiency. (Other Embodiments) In some printers using a photosensitive medium, the photosensitive medium is heated to an appropriate temperature before exposure. In such a printer, there has conventionally been a printer provided with a preheating heater upstream of the exposure head in the sheet feeding direction. Instead of this heater, the heat generated in the exposure unit may be guided by a Peltier element to heat the printing paper as in the above-described embodiment. This configuration also eliminates the need for a conventional heater, thereby saving power in the printer.

In the exposure head described above, a plurality of LEDs are provided on a printed circuit board, and the LEDs are cooled by cooling the printed circuit board. However, in some cases, the printed board is not provided. You may comprise so that a Peltier element may contact a LED directly and cool an LED directly. In this case, when an exposure head using a plurality of LEDs is configured, a plurality of combinations of an LED and a Peltier element may be provided. In this configuration, the temperature of each LED can be individually controlled,
The exposure amount can be precisely controlled.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of an optical head according to a preferred embodiment of the present invention.

FIG. 2 is an explanatory sectional view taken along line II-II of the optical head of FIG. 1;

FIG. 3 is an explanatory plan view showing a printed board and a light source (LED) of the optical head of FIG. 1 excluding an aperture plate.

FIG. 4 is an explanatory plan view of an aperture plate of the optical head of FIG. 1;

5 is a diagram illustrating the optical head and paper of FIG. 1 taken along line VV of FIG. 1;
FIG.

FIG. 6 is a schematic plan view of a printer according to a preferred embodiment including an optical head according to the present invention.

FIG. 7 is an explanatory sectional view taken along line VII-VII of the printer in FIG. 6;

FIG. 8 is an explanatory cross-sectional view of the optical head of the second embodiment at the same position as the line II-II in FIG. 1;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 photosensitive / pressure-sensitive printing paper 2 sheet-shaped base (base material) 3 image receiving layer 4 photosensitive / pressure-sensitive microcapsule layer 5 protective layer 10 printer 11 frames 11 a, 11 b side walls 12, 13 paper feed mechanism 14 exposure head (optical head) 14a Exposure section 14b Heat radiating section 15 Pressure developing head 16 Carriage 17 Guide mechanism 18 Scan position sensor 19 Scale 20 Controller 21 X direction drive mechanism 22 Z direction drive mechanism 23 Drive source 24 Pattern information source 25 Exposure head drive device 26 Peltier element drive Circuit 30 Pressure roller 50 Printed circuit board 51 Substrate body 52 Wiring pattern 53 Spacer plate 60 Peltier element 61 Thermoelectric material chip 62 Heat-absorbing side substrate 63 Heating-side substrate 70 Heat transfer section 71 Heating section 72 Heating roller 72a Shaft 73 Spring 74 Pressure roller Hole Reference Signs List 5 heating section structure 76 elongated hole 77 radiation fin 80 aperture plate 81 exposure table 82 heating table A, Ab1, Ab2, Ag1, Ag2, Ar1, Ar2, Ar3 aperture (opening) E beam Q paper feed pitch S, Sb, Sb1, Sb2, Sg, Sg1, Sg2, S
r, Sr1, Sr2, Sr3 Light source X, X1, X2 Scanning direction (row direction) Z Paper feed direction

Claims (8)

[Claims] 1. A light source comprising: a light source for forming a latent image on a photosensitive medium by exposing the photosensitive medium to light; and a Peltier element arranged with thermal conductivity to the light source; An optical head, wherein the light source is cooled by an element. 2. A light source for forming a latent image on a photosensitive medium by exposing the photosensitive medium, a printed circuit board on which the light source is mounted, and a substrate on a cooling side of the substrate. A Peltier element arranged and provided, and heat dissipating means arranged thermally conductive at a portion on the heat dissipation side of the Peltier element, wherein the light source is cooled by the Peltier element. An optical head, comprising: 3. The Peltier device driving control means for changing a cooling capacity of the Peltier device in accordance with a heat generation amount of the light source. Light head. 4. An optical printer comprising the optical head according to claim 1 as an exposure head for printing. 5. An optical head according to claim 2, wherein the optical head is provided as an exposure head for printing. An optical printer, wherein the optical printer is arranged so as to heat a conductive medium. 6. An optical head according to claim 2, wherein the optical head is provided as an exposure head for printing, and the optical head is disposed downstream of the exposure head in a feeding direction of a photosensitive medium. A pressure developing unit that develops a latent image formed on the photosensitive medium by pressing the photosensitive medium, wherein the heat radiating unit is located on the downstream side of the pressure developing unit in the feeding direction of the photosensitive medium. An optical printer, wherein the heat radiation surface faces the photosensitive medium and the photosensitive medium is arranged to heat the photosensitive medium. 7. The heat radiating means according to claim 5, wherein the heat radiating means is configured to heat the photosensitive medium by rolling on the photosensitive medium. Optical printer as described. 8. An optical head according to claim 2, wherein the optical head is provided as an exposure head for printing, and the optical head is disposed on an upstream side of the exposure head in a feeding direction of a photosensitive medium. An optical printer having a surface facing a photosensitive medium and arranged to heat the photosensitive medium.