JP2001096800A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recorder in which the emission quantity of a semiconductor emission light source can be increased, the number of the semiconductor emission light source can be decreased and the light source can be controlled easily. SOLUTION: The image recorder comprises an LED emission light source (semiconductor emission light source) wherein the light emitting section of the LED light source is cooled by a cooling means 2000 at the time of exposure and upper limit of emission is set higher than the rated quantity of light of the LED light source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image recording apparatus for forming an image by light exposure, and more particularly to an image recording apparatus for performing stable exposure at high speed and high resolution.

[0002]

2. Description of the Related Art In recent years, with the spread of Desk Top Publishing and the like, the work of editing an image input from a scanner on a computer software and performing page imposition has become common, and full digital editing has become commonplace. .

In such a process, an image setter output for directly outputting image-edited page data to a film, a computer-to-plate (CTP) output for directly recording an image on a printing plate, and a Is a computer to cylinder (CTC) for directly recording an image on a printing plate wound on a cylinder of a printing press.

In this case, once a film output or a printing plate output is performed only for the purpose of checking the proof, and printing proofing and proofreading with other proof materials are performed, waste of the film and the printing plate and unnecessary work are increased. There's a problem.

[0005] Therefore, in particular, in the step of creating and editing a full digital image by such a computer, the D
There is a demand for a system called DCP (Direct Digital Color Proof) for performing direct color image output.

[0006] Such a DDCP is used to record digital image data processed on a computer on a film for plate making using an image setter or the like, perform a final printing operation for directly creating a printing plate by CTP, or perform CTC. Before performing image recording directly on the printing plate wound on the cylinder of the printing press with, a color proof that reproduces the output target indicated by the digital image processed on the computer is created, and its pattern, color tone, This is for checking text characters and the like.

[0007] Further, in such a proofing process in the printing process, 1) confirmation of a mistake inside the work site, that is, an inner school, 2) an outer school submitted for confirmation of a finish to an orderer and a designer, 3) Proofs are created and used mainly for three purposes: a print sample provided as a sample of the final printed matter to the captain of the printing press.

[0008] At this time, for the purpose of checking the inside, and for some outside school applications, there are needs for shortening the delivery time and reducing costs.
There are cases where calibration materials that cannot reproduce halftone images, that is, calibration using the sublimation transfer method, and output products such as ink jet and electrophotography are mainly used as calibration for placement confirmation, but the reproducibility of highlights and fine In order to confirm details, etc., it is a reality that a proof that is reproduced with printing dots is also desired.

Therefore, as an apparatus for producing such a color proof, there is provided a drum and a rotation drive mechanism for rotating the drum, and the rotation drive mechanism holds the photosensitive material on the drum while holding the photosensitive material. There has been proposed an image recording apparatus that records a halftone image by exposing a laser beam according to a digital image signal while rotating the drum.

On the other hand, since a laser light source is expensive, another semiconductor light emitting light source (for example, LE
It is also considered to use D) as a light source.

[0011]

When a semiconductor light emitting light source is used as a light source, there are the following problems. (1) Since the light emission amount of each semiconductor light emitting light source is smaller than that of a laser light source, the number of LEDs is increased to increase the speed. Therefore, there is a problem that the control of the semiconductor light emitting light source becomes complicated.

(2) When an LED is used as a semiconductor light emitting source, if images are continuously recorded, the temperature of the LED rises, and the light emission amount of the LED fluctuates due to the temperature rise.

The control of the amount of light emission based on this temperature change is performed by LE
This is possible by monitoring the amount of light irradiation from D and performing feedback control. However, when the temperature of the LED rises, the wavelength of the LED also fluctuates due to the rise in temperature.

FIG. 13A is a diagram showing an example of the relationship between the temperature of the LED and the wavelength, and FIG. 13B is a diagram showing an example of the relationship between the wavelength and the sensitivity of the photosensitive material. For example, it is assumed that the temperature of the LED in the standard state (or the initial state) is 10 ° C., and has been increased to 30 ° C. by continuous use. At this time, the emission wavelength at 10 ° C. is 534 nm, and the emission wavelength at 30 ° C. is 540 nm.
Can be read from the temperature wavelength relationship in FIG.

Such a change in wavelength from 534 nm to 540 nm causes an increase in sensitivity, as can be seen from the wavelength sensitivity relationship shown in FIG. In the case of this specific example, the sensitivity is increased by about 20%, and a desired density cannot be obtained on the photosensitive material.

Further, as the temperature of a semiconductor light emitting light source such as an LED or a laser diode increases, the rated light amount decreases, the light emission amount must be reduced, and the life is shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide a semiconductor light emitting source having a large light emission amount, a small number of semiconductor light emitting light sources, and an image which is easy to control. A recording device is provided.

The second object is to use LE as a semiconductor light source.
An object of the present invention is to provide an image recording apparatus capable of obtaining an image having no change in the density of a photosensitive material due to wavelength fluctuation when D is used.

[0019]

According to a first aspect of the present invention, there is provided a semiconductor light emitting device, comprising: a semiconductor light emitting light source for cooling the semiconductor light emitting light source during exposure; Wherein the upper limit light amount exceeding the rated light amount is used as the upper limit of the light emission amount.

The rated current of a semiconductor light-emitting light source has the characteristic that it increases as the ambient temperature decreases, and that the amount of light emission increases as the value of the flowing current increases. By cooling the semiconductor light emitting light source, a large current can be passed through the semiconductor light emitting light source, and the amount of light emission can be increased.

By increasing the light emission amount of the semiconductor light emitting light source, the number of the semiconductor light emitting light sources can be reduced, and the light source control becomes easy. On the other hand, the life of the semiconductor light source is determined by the operating current and its temperature. By cooling, the temperature of the semiconductor light source can be lowered and the life can be secured.

Further, a large wavelength change due to a large temperature change caused by overheating can be suppressed, and a change in sensitivity of the photosensitive material can be reduced. As such a semiconductor light emitting light source, LE
D, a laser diode, a super luminescent diode (SLD) and the like.

According to a second aspect of the present invention, in the image recording apparatus according to the first aspect, the semiconductor light source is an LED. The cost is reduced by using the LED. LED is R (red), G (green), B (blue)
, RGB color exposure is possible.

According to a third aspect of the present invention, by the cooling,
3. The image recording apparatus according to claim 1, further comprising temperature control means for controlling the temperature to be constant. By making the temperature constant, the temperature control unit suppresses a change in sensitivity of the photosensitive material due to a wavelength variation, and suppresses a density variation to stably obtain an image.

According to a fourth aspect of the present invention, there is provided an LED chip comprising:
A plurality of LED light sources having a heat sink electrode of the LED chip, a resin lens encapsulating the LED chip, a block for holding the plurality of LED light sources side by side, and transferring heat from the heat sink electrode of the LED light source to the block An image recording apparatus comprising: a heat conductive member; and a cooling unit that cools the block.

The heat generated from the LED light source is transferred to the LE
By cooling from the heat sink electrode of the D light source via the heat conduction member, the cooling efficiency is good and heat is stored in the LED light source,
The rise in temperature can be effectively suppressed.

Therefore, a large current can be supplied to the LED light source, and a high light emission amount and a long life can be realized at low cost.
The image recording apparatus according to claim 4, wherein the block is made of metal, and the heat conducting member is made of heat conductive silicon filled between the block and the heat sink electrode. Device.

The block is made of metal, and the heat conducting member is made of heat conductive silicon filled between the block and the electrode portion of the LED light source. Therefore, the heat conductive member can be cooled through the block and the heat conductive silicon. It is possible to prevent the LED light source from accumulating heat and increasing the temperature.

Therefore, a large current can be supplied to the LED light source, and a high light emission amount and a long life can be realized at low cost.
In addition, the use of heat conductive silicon makes the production simple.

[0030] The invention according to claim 6 is characterized in that the heat conducting member is a metal electrically connected to each heat sink electrode of the plurality of LED light sources and thermally connected to the block. An image recording apparatus according to claim 4.

Since the metal is electrically connected to each of the heat sink electrodes of the plurality of LED light sources and is thermally connected to the block, it is possible to prevent the LED light source from storing heat and increasing the temperature.

Therefore, a large current can be supplied to the LED light source, and a high heat generation and a long life can be realized at low cost.
The invention according to claim 7 is characterized in that the cooling means has a Peltier element for cooling the block, a radiation fin connected to the Peltier element, and a fan for blowing air to the radiation fin. An image recording apparatus according to any one of claims 4 to 6.

As a result, the LED light source can be cooled, so that a large current can flow to the LED light source, and a larger amount of emitted light and a longer life can be realized at low cost. 8. The image forming apparatus according to claim 7, wherein a heat pipe is provided between a portion of the block near the Peltier element and a portion of the block away from the Peltier element. It is.

By providing a heat pipe between a portion of the block near the Peltier device and a portion of the block away from the Peltier device, a plurality of LEDs are provided.
Is cooled uniformly.

Therefore, it is possible to suppress the variation in the wavelength between the LEDs and the variation in the upper limit light emission amount. According to a ninth aspect of the present invention, there is provided the image recording apparatus according to any one of the fourth to eighth aspects, further comprising a temperature control unit for controlling the temperature to be constant by the cooling unit.

The cooling means has a temperature control means for controlling the temperature to be constant, thereby suppressing a change in sensitivity of the photosensitive material due to a wavelength fluctuation, and suppressing a fluctuation in density to stably obtain an image.

According to a tenth aspect of the present invention, the LED chip, the heat sink electrode of the LED chip, and the LE
An LED light source having a resin lens enclosing a D chip,
An image recording apparatus, further comprising a blower for blowing air toward a heat sink electrode of the LED light source.

The provision of the air blowing means for blowing air toward the heat sink electrode of the LED light source allows a simple structure to be achieved.
The effect of increasing the amount of emitted light by cooling the ED light source can be obtained.

According to an eleventh aspect of the present invention, a fin is formed on the heat sink electrode.
An image recording apparatus according to any one of the preceding claims. By forming the fins on the heat sink electrode, the cooling efficiency is improved, and a higher light emission amount and longer life can be realized.

According to a twelfth aspect of the present invention, there is provided the image recording apparatus according to any one of the first to eleventh aspects, wherein the LED light source is cooled to a temperature lower than the ambient air temperature. L
By cooling the ED light source to a temperature equal to or lower than the ambient air temperature, the ED light source can emit light with a light amount larger than the rated light amount at the ambient air temperature, the number of light sources can be reduced, and the light source control becomes easy.

[0041]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described below. In the following description, the meanings of the terms are explained. However, the meanings of the terms in the embodiments are only described, and the meanings of the terms of the present invention are not limited to this description. <Overall Configuration and Operation of Apparatus> First, the overall configuration and operation of an image recording apparatus according to an embodiment of the present invention will be described.

The image recording apparatus according to the present embodiment is an apparatus for obtaining a color proof for obtaining a proof to confirm the finish of a printed matter in advance from a digital image signal. Specifically, in producing a color print, before producing a printing plate from a digital image signal, a color proof for simulating an image obtained by printing from a digital image signal on a printing plate produced from the digital image signal is obtained. Create a layout on the image indicated by the digital image signal,
It is a device that creates a color proof in order to check for errors such as errors in colors, characters, etc., and to confirm the finish of printed matter in advance.

Further, in the image recording apparatus of this embodiment, a roll-shaped silver halide color photographic material is set as a photosensitive material, cut into a sheet at an exposure section, and then, in response to the digital image signal described above. Then, the substrate is exposed to a laser beam, and then developed in a developing section to create a color proof.

FIG. 2 is a schematic diagram showing the internal configuration of the image recording apparatus. The image recording apparatus has an exposure unit 3 for exposing an image on a photosensitive material and a processing unit 4 for developing the exposed photosensitive material.

The inside of the exposure section 3 has the following configuration. The roll set unit 10 is a part for loading a magazine 18 containing a roll of the photosensitive material P in a roll shape (see FIG. 2), and is provided at an upper portion of the apparatus main body. The loading of the magazine 18 is performed by opening and closing the paper feed cover 19. The roll setting section 10 of the present embodiment is a section for loading a magazine 18 containing a roll of the photosensitive material P (see FIG. 2), but may be a section capable of directly setting the roll of the photosensitive material.

The magazine 18 set in the roll set section 10 is a magazine containing rolls wound with the photosensitive surface of the photosensitive material P facing outward. When the roll setting section 10 can directly set a roll of photosensitive material, it is preferable to set a roll wound with the photosensitive surface of the photosensitive material P facing outward.

A roller pair 21 and a cutter 22 for cutting the photosensitive material into a predetermined length are provided vertically below the roll set portion 10 of the magazine for storing the photosensitive material P. Further, when the magazine is loaded, the roller pair 21
It is arranged at a position close to the outlet of the loaded magazine 18.

The squeeze roller 23 is provided vertically below the roller pair 21, and is capable of coming into contact with and separating from the drum 30 provided in the main scanning unit 30. The conveying path of the photosensitive material from the outlet of the magazine 18 to the squeeze roller 23 extends substantially vertically downward. When the photosensitive material P is supplied to the drum 30, the squeeze roller 23 is pressed against the drum 30 to bring the supplied photosensitive material P into close contact with the outer peripheral surface of the drum 30. Meanwhile, photosensitive material P
Is fed a predetermined length, the squeeze roller 23 stops, and the cutter 22 cuts the photosensitive material P into a sheet of a predetermined length. Thereafter, the squeeze roller 23 is driven to rotate to bring the photosensitive material P into close contact with the outer peripheral surface of the drum 30.

The peripheral speed of the drum 30 at the time of paper feeding is 2 m
/ Sec or less (especially 1 m / sec or less). As a result, the toner can be stably fed to the drum 30, the adhesion to the drum 30 is increased, and the retention by suction is improved. Also,
The peripheral speed of the drum 30 during paper feeding is 2 cm / sec or more (especially
cm / sec or more). Thereby, the feeding time can be reduced, and the image recording time and the image recording time interval can be reduced. In the device of the present embodiment, the speed is 0.1 m / sec.

The surface substrate of the squeeze roller 23 is made of rubber in the apparatus of the present embodiment, but is not limited to rubber, and may be an elastic material from the viewpoint of the adhesion of the photosensitive material P to the drum 30. preferable. Thereby, the photosensitive material P sufficiently adheres to the drum by the elastic deformation of the surface substrate of the squeeze roller 23.

The drum 30 is rotatable by a squeeze roller 23. When the photosensitive material P is fed, the photosensitive material P is fixed on the outer peripheral surface by air suction while being rotated by the squeeze roller 23. When the fixing of the photosensitive material P on the outer peripheral surface of the drum 30 is completed, the squeeze roller 23 is separated from the drum 30. When the squeeze roller 23 separates from the drum 30, the rotation driving mechanism of the drum 30 rotates the drum 30 at a higher rotation speed than the rotation speed during the close contact operation, so that the photosensitive material P is main-scanned during recording. It rotates at a high speed while fixing the photosensitive material P on the outer peripheral surface.

The peripheral speed of the drum 30 during image recording is
It is preferably at least 3 m / sec (particularly at least 5 m / sec, more preferably at least 10 m / sec). Thereby, the image recording time can be shortened. The peripheral speed of the drum 30 during image recording is preferably 70 m / sec or less (particularly 50 m / sec or less). Thereby, the peripheral speed of the drum 30 is stabilized,
The time required to stabilize the peripheral speed is shortened, and the cost of the device is reduced, and the device becomes safe. In the apparatus of the present embodiment, the peripheral speed of the drum 30 during image recording is about 30 (m / sec).

The optical unit 400 is disposed so as to face the drum 30, and is driven by the sub-scanning mechanism 300.
It moves parallel to the 0 axis of rotation. Also, the optical unit 40
0 is the photosensitive material P on the drum 30 receiving the digital signal.
Then, an image is written by an LED chip.

The rotation of the drum 30 on which the photosensitive material P is fixed on the outer peripheral surface corresponds to the main scanning and the optical unit 4.
00 is moved in a direction parallel to the rotation axis of the drum 30 as sub-scanning, and exposure is performed in accordance with a digital image signal.
The latent image of the halftone dot image is recorded on the photosensitive material P.

The paper discharging section 50 has a peeling guide 51 which can be brought into contact with and separated from the drum 30. The peeling guide 51 is usually
When the drum 30 is stopped after being separated from the drum 30 and the image writing is completed, the peeling guide 51 comes into contact with the drum 30, and the squeeze roller 23 is pressed against the drum 30.
The squeeze roller 23 is driven to rotate to rotate the drum 30, and the peeling guide 51 peels the photosensitive material P from the drum 30.

The peripheral speed of the drum 30 when the photosensitive material is peeled from the drum 30 is preferably 2 m / sec or less from the viewpoint of stable peeling and prevention of breakage of the tip of the photosensitive material. 0.01m /
It is preferably at least seconds. In the device of the present embodiment,
The peripheral speed of the drum 30 when peeling the photosensitive material from the drum 30 is about 0.05 to 0.1 m / sec.

When the separation of the photosensitive material P is completed, the separation guide 51 is separated from the drum 30. Then, the paper discharge unit 50
Sends the peeled photosensitive material P to the development processing unit 4. Also,
The development processing unit 4 includes a color development processing unit 42, a bleach-fix processing unit 43, a stabilization processing unit 44, a drying unit 45, and a discharge tray 4
6 is provided. When using a chemical fog type direct positive photosensitive material, color development processing, bleach-fixing processing, stabilization processing,
Processing is performed in the order of drying, and the developed photosensitive material P is discharged to a discharge tray 46.

A second exposure unit 41 for uniformly exposing the photosensitive material after completion of image writing, which is sent from the exposure unit 3 side, is provided, and when an internal latent image type direct positive photosensitive material is used. The second exposure section 41 is for exposing in the state where the photosensitive material P is present in the color developing solution, and the second exposure section 41 and the color developing section 42 in FIG. 2 are substantially composed of one processing tank. The portion of the shallow processing tank is a second exposure unit 41.

Next, the drum 30 and the optical unit 40
Based on FIG. 3 which is a plan view showing the periphery of
0 and the periphery of the optical unit 400 will be described. The drum 30 is provided with shaft portions 31 and 32 at both ends of the rotation shaft. The shaft portions 31 and 32 of the drum 30 are rotatably supported on a support base 34 via bearings. Drum 30
The rotation drive mechanism for rotating the drum about the rotation axis is a drum 3
0, a drive pulley 35 provided on one of the shaft portions 32, an output pulley 38 which is motively connected to the drive pulley 35 via a belt 36, a drum rotation motor M6 for rotating the output pulley 38, and a belt. 36, the drum rotation motor M6 rotates the output pulley 38, and the driving force is transmitted to the driving pulley 35 via the belt 36 to
0 is rotationally driven. The drum rotation motor M6 is a motor that can release the excitation. Since the motor is normally excited, there is resistance when trying to rotate the motor shaft by another mechanism. However, the drum rotation motor M
By releasing the excitation, 6 can prevent resistance when the drum 30 is rotated by another mechanism.

A rotary encoder 37 is provided on one shaft of the drum 30 and further outside the position where the driving pulley 35 is provided, and a pulse signal output from the rotary encoder 37 is used for writing control. Used. The other shaft 31 of the drum is connected to a suction blower 39.

The drum 30 is recorded as a hollow aluminum body and has a large number of suction holes penetrating from the outer peripheral surface of the drum 30 to the inside thereof. The pressure inside is reduced, and the photosensitive material P can be fixed on the surface of the drum 30 by air suction.

The diameter of the drum 30 is set to a value of 10 from the viewpoint of the usefulness of the color proof to be produced, curl, exposure accuracy, and the like.
cm or more, and an LED chip or
In order to obtain a good image easily and at high speed in an optically conjugate relationship between the LED light source (unit) having the LED chip and the photosensitive material, the distance is preferably 15 cm or more (particularly 20 cm or more). Equipment cost, equipment size,
The thickness is preferably 1 m or less (particularly 50 cm or less, more preferably 40 cm or less) from the viewpoints of manufacturability for obtaining the required exposure accuracy and a small adverse effect of thermal expansion. In addition, in the apparatus of this embodiment, it is 29 cm.

The width of the drum 30 (the length of the outer peripheral surface of the drum 30 in the rotation axis direction) is preferably 30 cm or more (especially 50 cm or more) from the viewpoint of the usefulness of the color proof to be produced. Equipment cost, equipment size,
From the viewpoint of manufacturability to obtain the required exposure accuracy, 1.
It is preferably 5 m or less (especially 1 m or less). As a result, there is no need for special mechanical strength, so that the cost is reduced,
Further, since the machine weight is not large and the installation place is not particularly limited, it can be installed at a highly convenient position. In addition, in the apparatus of this embodiment, it is about 60 cm.

The sheet width of the photosensitive material P to be exposed (the length of the photosensitive material P in the direction of the rotation axis of the drum 30) depends on the cost of the apparatus, the size of the apparatus, and the manufacturability for obtaining the required exposure accuracy. To 1.5 m or less, so that the size in the drum axis direction can be small, and the weight for obtaining the structural accuracy and strength required for the drum itself, the drum mounting portion, and the optical scanning portion can be reduced. , It is possible to eliminate the need to select an installation location. In addition, it is preferably at least 25 cm (especially 50 cm or more) from the viewpoint of the usefulness of the produced color proof.

The length of the sheet of the photosensitive material P to be exposed (the length of the photosensitive material P in the rotating direction of the drum 30) is determined in view of the apparatus cost, the apparatus size, and the manufacturability for obtaining the required exposure accuracy. To a maximum of 2 m or less (especially 1.5 m or less).
Processing accuracy can be easily obtained, the weight required for obtaining the required structural accuracy and strength can be reduced, and the installation location can be selected. In addition, it is preferably at least 25 cm or more from the viewpoint of the usefulness of the produced color proof.

The sheet size of the photosensitive material P to be exposed is preferably 0.06 square meters or more (particularly 0.12 square meters or more) from the viewpoint of the usefulness of the produced color proof. Further, the size is preferably 3 m 2 or less (especially 2 m 2 or less), whereby the size of the device can be reduced and the weight for obtaining the required structural strength can be reduced to any location.

In the apparatus of the present embodiment, the width and length of the photosensitive material P to be exposed are 57 cm × 3.
It corresponds to the size of 5cm, 57cm x 70cm, 57cm x 85cm, and in the case of the size of 57cm x 35cm,
When the effective image area is 55.5 cm x 33.7 cm, an A3 size image can be reproduced. In the case of 57 cm x 70 cm, the effective image area is 55.5 cm x 67.4 cm, and an A2 size image can be reproduced. 57 cm x 85 cm Size, the effective image area is 55.5 cm × 82.8 cm and B2
Can reproduce the image of the size.

Next, the sub-scanning mechanism 300 for moving the optical unit 400 to perform sub-scanning will be described with reference to FIG. The optical unit 400 is fixed to the metal belt 340, and is guided by a pair of guide rails 341 and 342 provided in parallel with the rotation axis of the drum 30 and can move in parallel with the rotation axis of the drum 30. The metal belt 340 is wound around a pair of pulleys 343 and 344,
Reference numeral 4 is directly connected to a rotation shaft 345 of the drive motor M7.
When the drive motor M7 rotates the rotating shaft 345, the pulley 344 fixed to the rotating shaft 345 rotates,
The metal belt 340 wound around the pulley 3 and the pulley 344 rotates. Then, the optical unit 4 is attached to the metal belt 340.
00 moves parallel to the rotation axis of the drum 30.

The drive motor M7 is connected to the optical unit 4
When the optical unit 400 is moved backward, the rotation speed is faster than that during the forward movement, and the optical unit 400 is returned at a faster moving speed than when the forward movement. In order to make it rotate, it is driven at high speed.

The optical unit 400 stops at the sub-scanning reference position, starts sub-scanning from this position, and returns to the sub-scanning reference position when the sub-scanning is completed with a movement amount corresponding to the image size.

As shown in FIG. 3, an encoder 37 for detecting the rotation position of the drum 30 is mounted coaxially with the rotation shaft 90 of the drum 30. The encoder 37 outputs a pulse signal, and outputs a tip position signal of the photosensitive material P from a tip position sensor S9 that detects the tip position of the photosensitive material P. Based on these signals, the writing control and the rotation of the drum rotation motor M6 are performed. Perform rotation control. The drum rotation motor M6 rotates the drum 30 at high speed using a servomotor.

The image recording density of the image recorded on the photosensitive material P is 600 dpi or more (especially 1000 dpi or more, further 1200 dpi or more) in both the main scanning direction and the sub-scanning direction from the viewpoint of the reproducibility of gradation by a halftone dot image. )
In addition, from the viewpoints of saturation of gradation reproducibility by a halftone image, image recording speed, and apparatus cost, 10,000 dpi or less (especially 5000 dpi) in both the main scanning direction and the sub-scanning direction.
i or less) is preferred. The image recording density of the image recorded on the photosensitive material in the apparatus of this embodiment is 2000 dpi in both the main scanning direction and the sub-scanning direction. Needless to say, the image recording densities in the main scanning direction and the sub-scanning direction indicate how many pixels to be image-recorded are arranged within one inch in the main scanning direction or the sub-scanning direction. It is indicated in units of dpi.

One halftone dot is 100 or more (especially 2 dots).
(00 or more) is preferable because the reproduction is close to halftone dots of actual printing. Further, it is preferable that one halftone dot is recorded from 5000 or less (especially, 2000 or less) pixels because the handling of image data is easy and the image data can be processed at high speed.

The RIP 200 provided outside the apparatus 1 and connected to the apparatus 1 converts Y, M, C, and K halftone raster image format digital halftone dots from image data for electronic plate making which is the basis of electronic plate making. Image data is generated for each color in order (surface-sequential).

It is preferable to reproduce the image data for electronic plate making from a set of halftone dots having the same screen ruling as that of the printed matter from the image data for electronic plate making, and reproduce the pixel gain amount by approximating that of the printed matter. As a result, not only can the printed halftone image be faithfully reproduced, but also tone jumps, moirés, and image defects, which are common problems in electronic plate making image data, can be accurately reproduced and calibrated. of course,
The approximate calibration does not require faithful reproduction up to that point, and the approximate calibration is possible with a halftone image.

Then, the RIP 200 sends the generated digital halftone image data to the image data I / F section 500 in the order of each color (screen-sequential). Image data I / F section 500
Represents each color (Y, M, C,
The halftone image data of the raster image format (BK) is converted into an exposure format for each of the number of scanning lines simultaneously recorded in one main scan, and stored in an external storage device attached to the image data I / F unit 500. Then, the digital halftone image data converted into an exposure format for each scanning line (for one main scan) is stored in an external storage device attached to the image data I / F section 500 in the Y, M, C, and K colors. After one image is stored, the image data I / F unit 500 stores Y, M, C,
The pixel data composed of all the K data is read out in an exposure format for each scanning line number, and the data of all colors is transmitted to the image recording control unit 100 simultaneously (dot-sequentially).

The image recording control unit 100 transmits the transmitted Y,
Control is performed such that an image is exposed on the photosensitive material P based on image data obtained by converting pixel data including all data of M, C, and K into an exposure format for each scanning line.

FIG. 4 is a schematic diagram showing an example of the optical configuration of the optical unit 400 of the image recording apparatus according to the present invention. In the optical unit 400, a red LED unit 420, a green LED unit 421, and a blue LED unit 422, which are characteristic parts of the present invention, are arranged.

Part of the light from the red LED unit 420 is reflected by the mirror 425, passes through the dichroic mirrors 426 and 427, and enters the imaging optical system 431. Also, some light from the green LED unit 421 is
The light is reflected by the dichroic mirror 426, passes through the dichroic mirror 427, and enters the imaging optical system 431. Further, a part of the light from the blue LED unit 422 is reflected by the dichroic mirror 427 to form the image forming optical system 431.
to go into. The imaging optical system 431 includes the red LED unit 420, the green LED unit 421, and the blue L
An image is exposed on the photosensitive material P by an imaging optical system in which the lens of the ED unit 422 and the photosensitive material on the drum 30 are conjugate.

The image forming optical system 431 in FIG.
The front lens of each of the LED units 420 to 422 and the photosensitive surface of the photosensitive material P are configured to be substantially optically conjugate. In addition to having such a conjugate relationship, the LED unit 420 is located at the position of the photosensitive material P.
It is also a reduction optical system in which light from .about.422 is reduced and projected.

<First Embodiment> Here, referring to FIG. 1, a red LE which is a feature of the embodiment of the present invention will be described.
The D unit 420, the green LED unit 421, and the blue LED unit 422 will be described. In addition, red LE
Since the D unit 420, the green LED unit 421, and the blue LED unit 422 have the same structure,
The description will be made using the ED unit 420, and the description of the green LED unit 421 and the blue LED unit 422 will be omitted.

In FIG. 1, (a) is a front view, and (b) is a right side view of (a). A box-shaped block 1000 made of a metal having a good thermal conductivity (for example, copper or aluminum) and having one open surface is used as a base block 100.
1 and standing wall blocks 1002, 1003, 1004, 1005 standing on the side of the base block 1001.
It is composed of

The base block 1001 is provided with a plurality of holes 1007 at equal pitches. This hole 1007
, An LED light source 1010 is held. In this embodiment, the plurality of holes 1007 are 5 rows (sub-scanning direction) × 6.
The first group A is composed of columns (main scanning direction), and the second group B is composed of 5 rows × 6 columns. The arrangement of the holes 1007 in the row direction of the first group A and the second group B is a predetermined arrangement. It is shifted by the pitch L2.

The pitch L2 is set to be the same as or slightly smaller than the diameter of the light emitting portion of the LED light source 1010. Therefore, the LED units 420, 421, and 422 disposed along the main scanning direction are arranged in the main scanning direction. , The borders are in contact with each other or partially overlap each other.

As shown in FIG. 6, the LED light source 1010 has an LED (chip) 1013 sealed in a resin lens 1011. One of the two electrodes 1015 and 1017 (heat sink electrode) 1015 is connected to the other. The light emitting portion of the LED 1013 is set to be thicker than the electrode 1017.
(Light-Emitting Junction) It functions as a heat-dissipating electrode (heat sink) for dissipating the heat at 1019 to the outside.

Returning to FIG. 1, a cooling means 2000 is connected to the block 1000. The cooling means of this embodiment is provided by the standing wall block 100 of the block 1000.
4, a Peltier element 2100 that cools the block 1000, a fin 2200 that is connected to the Peltier element 2100, and that keeps heat well, and a fan 230 that cools the fin 2200 by blowing air to the fin 2200.
0.

Further, the electrodes 1015, 1 of the LED light source 1010 are provided on the base block 1001 of the block 1000.
A frame 1100 is formed so as to surround 017.

The frame portion 1100 is filled with heat conductive silicon 3000 having high electrical insulation and transmitting heat from the electrode (heating electrode) 1017 of the LED light source 1010 to the block 1000.

Further, a block 1000 includes a temperature sensor.
(Thermistor) 490 is attached. Therefore, L
The heat generated in the light emitting portion 1019 of the LED 1013 of the ED light source 1010 is supplied to the electrode 1015 and the heat conductive silicon 3000.
To block 1000.

The standing wall block 1005 provided below the block 1000 is formed of a heat insulating member to prevent heat from flowing from the base of the optical unit 4000.

On the other hand, the Peltier device 2 of the cooling means 2000
By driving the fan 100 and the fan 2300, the light emitting unit 1019 of the LED 1013 of the LED light source 1010 is cooled.

Next, the electrical configuration of the optical unit 400 of the image recording apparatus will be described with reference to FIG. As shown in FIG. 5, the image recording control unit 100 includes a C that controls each unit.
PU 101, RAM 102 storing various tables,
The data processing unit LUT 103 and the LED unit 42 that sequentially convert the exposure format transmitted from the image data I / F unit 500 and supply the data to the drivers D420 to D422.
Drivers D420 to D4 for driving 0, 421, 422
22 are arranged.

The sensors connected to the CPU 101 include an encoder 37 for detecting the rotational position of the drum 30, a tip position sensor S9 for detecting the tip position of the photosensitive material P, and the LED units 420, 421, and 422. There is a temperature sensor 490 and the like. The actuator group includes a drum rotation motor M6, a sub-scanning drive motor M7, LED units 420, 421, and 42.
2 Peltier element 2100, fan 2300, etc.
It is driven under the control of the PU 101.

A densitometer 480 is provided to detect the density obtained on the photosensitive material P by exposure from the LED chips of each LED unit. Then, a predetermined test patch is recorded and developed, and
The operator sets the density of the photosensitive material discharged to 6 on the densitometer 480, thereby obtaining the density characteristic value of the photosensitive material.

By the way, in the LED, the current (rated current) that can be passed through the LED is determined depending on the ambient temperature. That is, as shown in FIG. 7 showing the relationship between the ambient temperature and the rated current and rated light amount (relative light amount) of the LED,
Rated current (●) increases as the ambient temperature decreases,
It has the characteristic that the light emission amount (relative light amount: ○) can be increased as the value of the flowing current increases.

On the other hand, in the present embodiment, the cooling means 200
By using 0, the light emitting unit 1019 of the LED 1013 can be forcibly cooled, and the temperature of the light emitting unit 1019 can be kept lower than the ambient temperature.

For example, when the ambient temperature in the device is about 40 ° C., the temperature of the light emitting section 1019 can be maintained at about 25 ° C., and the operating temperature can be the same as that at the ambient temperature of 25 ° C.
For example, at an ambient temperature of 40 ° C., the rated current of the LED 1013 is 25 mA, and the upper limit light quantity is 1.1 as a relative ratio. However, when the light emitting unit 1019 of the LED 1013 is kept at 25 ° C. The rated current at 25 ° C. allows a current to flow up to 30 mA, and the upper limit light amount is 1.25 as a relative ratio.

That is, by cooling the light emitting portion 1019 of the LED 1013 by the cooling means 2000,
A large current can be passed to 013, and the light emission amount increases.

On the other hand, the life of the LED 1013 is determined by the operating current and the temperature of the light emitting unit 1019. By cooling, the temperature of the light emitting unit 1019 can be lowered and the life can be ensured.

Therefore, by increasing the light emission amount of the LED light source 1010, the number of the LED light sources 1010 can be reduced, and the light source control is facilitated. Also, the LED light source 101
By using 0, cost can be reduced and RGB color exposure can be performed.

Further, the CPU 101 fetches the output of the temperature sensor 490 and sends the block 1000 (LED light source 10
By keeping the temperature of the light emitting portion 1019) of the ten LEDs 1013 constant, a change in the sensitivity of the photosensitive material due to a wavelength change is suppressed, and an image without a density change can be obtained.

<Second Embodiment> In the first embodiment, the LED light source 10
Block the heat from the 10 heat sink electrodes 1015
000, but may have a configuration as shown in FIG.

This embodiment is the same as the first embodiment except for the following differences. 8, FIG. 8A is a front sectional view, and FIG. 8B is a view taken in the direction of arrow I in FIG. 8A.

Heat sink electrode 1 of LED light source 1010
015 was connected by a conductive metal (copper or aluminum) plate 3100 having good thermal conductivity to form a common electrode. In addition, LED
The other electrode 1017 of the light source 1010 and the conductive metal plate 3
100 is separated from the other via an insulating member.

Further, the metal plate 3100 includes an insulating layer 3110
Is thermally connected to the frame 1100 of the block 1000 via the. According to the above configuration, the LED light source 1010
The heat generated in the light emitting portion 1019 of the LED 1013 is transmitted to the block 1000 via the heat sink electrode 1015 and the metal plate 3100.

Therefore, a large current is supplied to the LED light source 1010
And a light source with good optical efficiency and cooling efficiency can be realized at low cost. Further, by using the metal plate 3100, the cooling efficiency is good. <Third Embodiment> The difference between this embodiment and the first embodiment is the LED unit.

This embodiment is the same as the first embodiment except for the following differences. In FIG. 9 showing the third embodiment, a block 5000 made of a metal having good thermal conductivity (for example, copper or aluminum) includes a base block 5001 and standing walls provided on both sides of the base block 5001. Blocks 5002 and 5003 are provided.

[0108] A plurality of holes 5007 are formed in the base block 5001 at an equal pitch. This hole 5007
, An LED light source 1010 is held. In the present embodiment, the plurality of holes 5007 are 5 rows (sub-scanning direction) × 6.
The first group A is composed of columns (main scanning direction), and the second group B is composed of 5 rows × 6 columns. The arrangement of the holes 5007 in the row direction of the first group A and the second group B is a predetermined arrangement. It is shifted by the pitch L2.

The standing wall lock 5002 is provided with the same cooling means 2000 as in the first embodiment. Also, as shown in FIG. 10 showing a cross section taken along line II of FIG. 9, the base block 5001 and the electrodes 1015, 101 of the LED light source 1010 are provided.
7 and filled with heat conductive silicon 3000,
The heat from the electrode (heating electrode) 1017 of the ED light source 1010 is transmitted to the base block 5001.

Returning to FIG. 9, the standing wall block 500 provided with the base block 5001 and the Peltier element 2100
2 is thermally connected to two heat pipes 5100 and 5200.

Further, the standing wall block 5003 provided below the base block 5001 is formed of a heat insulating material.
The heat from the base of the optical unit 400 does not flow.

One heat pipe 5100 connects the upright wall block 5002 and the boundary between the first group A and the second group B of the base block 5001, and the other heat pipe 5100
200 is a standing wall block 5002 and a standing wall block 500
It is provided so as to connect to the base block 5001 in the vicinity of 3.

According to the above configuration, one heat pipe 5
100 is the standing wall block 5002 and the base block 50
01 is connected to the boundary between the first group A and the second group B, and the other heat pipe 5200 is provided so as to connect the standing wall block 5002 and the base block 5001 near the standing wall block 5003, that is, a Peltier. A portion near the element 2100 and the Peltier element 21 of the base block 5001
Heat pipes 5100, 5
200, the plurality of LED light sources 1010
Is cooled uniformly. <Fourth Embodiment> The difference between this embodiment and the first embodiment is the LED unit.

The present embodiment is the same as the first embodiment except for the following differences. In FIG. 11 showing the fourth embodiment, a block 6000 is made of a metal having good thermal conductivity (for example, copper or aluminum), and a block 6000 is provided upright on a side of the base block 6001. And a standing wall block 6002.

The base block 6001 is provided with a plurality of holes 6007 at equal pitches. This hole 6007
The base block 6001 holding the LED light source 1010 and the electrodes 1015 and 1010 of the LED light source 1010
Between 17 and 17 is filled with heat conductive silicon 3000,
The heat from the electrode (heating electrode) 1017 of the LED light source 1010 is transmitted to the base block 5001.

Further, the standing wall lock 5002 is provided with the same cooling means 2000 as in the first embodiment, and a fan 6500 for blowing air toward the electrode 1017 of the LED light source 1010 is provided.

According to the above configuration, since the fan 6500 that blows air toward the electrode 1015 of the LED light source 1010 is provided, the configuration of the cooling unit 2000 is simplified.
By providing the fins 6600 as shown in FIG. 12 on the electrodes (heating electrodes) 1015 of the LED light source 1010, the cooling efficiency is further improved.

[0118]

As described above, according to the first aspect of the present invention, the rated current of the semiconductor light emitting source increases as the ambient temperature decreases, and the emission amount increases as the flowing current value increases. Has characteristics.

By cooling the semiconductor light emitting light source, a large current can flow through the semiconductor light emitting light source, and the amount of light emission can be increased. By increasing the light emission amount of the semiconductor light emitting light source, the number of the semiconductor light emitting light sources can be reduced, and the light source control becomes easy.

On the other hand, the life of the semiconductor light source is determined by the operating current and its temperature. By cooling, the temperature of the semiconductor light source can be lowered and the life can be secured. Further, a large wavelength change due to a large temperature change caused by overheating can be suppressed, and a change in sensitivity of the photosensitive material can be reduced. According to the second aspect of the present invention, the cost is reduced by using the LED. Further, since there are LEDs of each color of R (red), G (green), and B (blue), RGB color exposure can be performed.

According to the third aspect of the present invention, the temperature control means keeps the temperature constant, thereby suppressing the sensitivity change of the photosensitive material due to the wavelength fluctuation, and suppressing the density fluctuation, thereby obtaining a stable image.

According to the fourth aspect of the present invention, the LED
By cooling the heat generated from the light source from the heat sink electrode of the LED light source via the heat conducting member, the cooling efficiency is good and the LED light source is effectively kept from being trapped in heat and increasing in temperature.

Accordingly, a large current can be supplied to the LED light source, and a high light emission amount and a long life can be realized at low cost.
According to the invention described in claim 5, the block is made of metal and the heat conductive member is made of heat conductive silicon filled between the block and the electrode portion of the LED light source. Coolable through silicon, LE
The heat buildup in the D light source and the rise in temperature can be suppressed.

Therefore, a large current can be supplied to the LED light source, and a high light emission amount and a long life can be realized at low cost.
In addition, the use of heat conductive silicon makes the production simple.

According to the invention described in claim 6, each of the plurality of LED light sources is electrically connected to each heat sink electrode,
Since the metal is thermally connected to the block, it is possible to prevent the LED light source from accumulating heat and increasing the temperature.

Therefore, a large current can be supplied to the LED light source, and a high heat value and a long life can be realized at low cost.
According to the seventh aspect of the present invention, the LED light source can be cooled, so that a large current can flow to the LED light source, and a larger amount of emitted light and a longer life can be realized at low cost.

According to the eighth aspect of the present invention, since a heat pipe is provided between a portion of the block near the Peltier element and a portion of the block away from the Peltier element, a plurality of LEDs can be uniformly arranged. Is cooled.

Accordingly, it is possible to suppress the variation in the wavelength between the LEDs and the variation in the upper limit light emission amount. According to the ninth aspect of the present invention, the cooling means has a temperature control means for controlling a temperature to be constant, thereby suppressing a change in sensitivity of the photosensitive material due to a wavelength change, and suppressing a density change to stably. You can get an image.

According to the tenth aspect of the present invention, by providing the air blowing means for blowing air toward the heat sink electrode of the LED light source, the effect of increasing the amount of emitted light by cooling the LED light source can be achieved with a simple configuration. can get.

According to the eleventh aspect of the present invention, since the fins are formed on the heat sink electrode, the cooling efficiency is improved, and a higher light emission amount and a longer life can be realized. Claim 12
According to the described invention, by cooling the LED light source to a temperature equal to or lower than the ambient air temperature, the LED light source can emit light with a light amount larger than the rated light amount of the ambient air temperature, the number of light sources can be reduced, and light source control becomes easy.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an LED unit which is a characteristic part of the first embodiment.

FIG. 2 is a schematic diagram illustrating an internal configuration of the image recording apparatus.

FIG. 3 is a plan view illustrating the periphery of a drum and an optical unit in FIG. 2;

FIG. 4 is a schematic diagram illustrating an example of an optical configuration of an optical unit of the image recording apparatus of FIG.

FIG. 5 is a diagram illustrating an electrical configuration of an optical unit of the image recording apparatus of FIG.

FIG. 6 is a diagram illustrating an LED light source.

FIG. 7 is a diagram illustrating a relationship between an ambient temperature of an LED light source, a rated current, and a light amount (relative light amount).

FIG. 8 is a diagram illustrating a second embodiment.

FIG. 9 is a diagram illustrating a third embodiment.

FIG. 10 is a diagram showing a cross section taken along line II of FIG. 9;

FIG. 11 is a diagram illustrating a fourth embodiment.

FIG. 12 is a diagram illustrating another embodiment.

13A is a diagram illustrating an example of a relationship between the temperature of the LED and the wavelength, and FIG. 13B is a diagram illustrating an example of the relationship between the wavelength and the sensitivity of the photosensitive material.

[Explanation of symbols]

 1010 LED light source 2000 Cooling means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Oishi 1 Sakuracho, Hino-shi, Tokyo Inside Konica Corporation (72) Inventor Yasuaki Tamakoshi 591-7, Kazahirose, Oyama, Sayama-shi, Saitama F-term ( Reference) 2C162 AE12 AE23 AE28 AE48 AE77 AE96 AF15 AF16 AF29 AF86 FA04 FA17 FA34 FA44 FA64 2H106 AA41 AA76 AB73

Claims (12)

[Claims] 1. A semiconductor light-emitting light source, wherein the semiconductor light-emitting light source is cooled at the time of exposure, and an exposure is performed with an upper limit light amount exceeding a rated light amount of the semiconductor light-emitting light source as an upper limit of the light emission amount. Image recording device. 2. The image recording apparatus according to claim 1, wherein said semiconductor light source is an LED. 3. The apparatus according to claim 1, further comprising temperature control means for controlling the temperature to be constant by said cooling.
The image recording apparatus as described in the above. 4. An LE having an LED chip, a heat sink electrode of the LED chip, and a resin lens enclosing the LED chip.
A plurality of D light sources; a block for arranging and holding the plurality of LED light sources; a heat conducting member for transmitting heat from a heat sink electrode of the LED light source to the block; and cooling means for cooling the block. Image recording device. 5. The image recording apparatus according to claim 4, wherein the block is made of metal, and the heat conductive member is made of heat conductive silicon filled between the block and the heat sink electrode. 6. The image according to claim 4, wherein the heat conducting member is a metal electrically connected to each heat sink electrode of the plurality of LED light sources and thermally connected to the block. Recording device. 7. The cooling means includes a Peltier element for cooling the block, a radiator fin connected to the Peltier element, and a fan for blowing air to the radiator fin. The image recording device according to any one of the above. 8. The image forming apparatus according to claim 7, wherein a heat pipe is provided between a portion of the block near the Peltier device and a portion of the block away from the Peltier device. 9. An image recording apparatus according to claim 4, further comprising a temperature control means for controlling a temperature to be constant by said cooling means. 10. An LED chip, a heat sink electrode of the LED chip, an LED light source having a resin lens enclosing the LED chip, and a blower for blowing air toward the heat sink electrode of the LED light source. Image recording device. 11. An image recording apparatus according to claim 10, wherein fins are formed on said heat sink electrode. 12. The image recording apparatus according to claim 1, wherein said LED light source is cooled to a temperature equal to or lower than an ambient air temperature.