JPH01186352A - Apparatus and method for controlling output of laser beam - Google Patents

Abstract

PURPOSE:To inexpensively form an image having high image quality by guiding laser beam to a quantity-of-beam detection means through a filter having the beam pervious characteristic corresponding to the wavelength sensitivity characteristic of a photosensitive material and controlling the output of laser beam on the basis of the detected quantity of beam. CONSTITUTION:When reference image data d1, d2 for exposing a photosensitive material F to low and high densities are supplied to a D/A converter 44a from a ROM 50 on the basis of the order of a CPU 48, said data are converted to analogue signals which are, in turn, supplied to an amplifying circuit 46a to form drive currents 37a while laser beams are outputted from an LED 32a. Said laser beams are incident to a quantity-of-beam detector 35a through a filter 37a to be converted to electric signals and supplied to the CPU 48 as the quantities of beam q1, q2. The CPU 48 compares said quantities with the quantities of beam Q1, Q2 in an ideal state to calculate the correction offset quantity and correction gain of the circuit 46a and outputs the same to a buffer 54. When the buffer 54 supplies said correction data to the circuit 46a, a corrected drive current flows to the LED 32a to obtain beams having desired quantities of beam Q1, Q2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a light beam output adjustment device for recording images, etc. by scanning a photosensitive material, and a method for adjusting the output of the light beam. is guided to a light detection means through a filter with light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material, the amount of light is detected, and the output of the light beam is adjusted based on the amount of light, thereby producing a high-quality image. The present invention relates to a light beam output adjusting device and a method for adjusting the same.

[Background of the Invention] For example, there is an image recording device that records an image or the like by scanning an exposure head along a photosensitive material such as a film.

In this case, the exposure head has a light emitting element such as an LED, and by driving and controlling the light emitting element based on an image signal, the intensity of the light beam is modulated and an image or the like is recorded on the photosensitive material.

By the way, in such an image recording device, if the adjustment of the circuit that converts the image signal into a drive signal for the light-emitting element is not appropriate, or if the characteristics of the light-emitting element change over time, it may be difficult to record an accurate image on the photosensitive material. It becomes impossible to record. Therefore, for example, the light beam output from the light emitting element may be monitored using a light amount detection means, and the gain of the drive circuit of the light emitting element may be adjusted, or a predetermined image may be printed on the photosensitive material based on the reference image signal. Adjustment operations such as correcting the image signal in advance based on the density of the image and supplying the corrected image signal to the drive circuit are performed.

On the other hand, in the image recording apparatus, if an attempt is made to record an image or the like on the photosensitive material of one light emitting element, it will take a long time to obtain the desired image or the like. Therefore, a method has been proposed in which a plurality of pixels are formed on a photosensitive material at the same time by forming an exposure head with a plurality of light emitting elements and causing each light emitting element to emit light at the same time, thereby shortening the recording time.

However, if the light intensity of the light beams output from the plurality of light emitting elements for the same image signal is not the same, periodic unevenness will occur on the photosensitive material corresponding to the number of light emitting elements constituting the exposure head. occurs in the direction in which the light emitting elements are arranged. In this case, the unevenness is similar to the case described above.
This can be removed by adjusting the gain of the drive circuit, etc. However, the sensitivity characteristics of photosensitive materials depend not only on the amount of light beam but also on the wavelength. Therefore, if there is a shift in output wavelength between light emitting elements that emit light simultaneously due to individual differences or changes over time, periodic unevenness will occur in images etc. if the output of each light emitting element is adjusted without considering the wavelength.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and includes guiding a light beam to a light amount detection means through a filter having light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material. , to provide a light beam output adjustment device and its adjustment method, which make it possible to form high-quality images at extremely low cost by adjusting the output of the light beam based on the amount of light detected by the light amount detection means. The purpose is to

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a filter having light transmission characteristics corresponding to the wavelength sensitivity characteristics of a photosensitive material on which an image or the like is recorded by an intensity-modulated light beam. , a light amount detection means for receiving a light beam through the filter and detecting the light amount; and a correction means for correcting the output of the light beam so that the light amount detected by the light amount detection means becomes a predetermined light amount. It is characterized by being prepared.

Further, the present invention is characterized in that the filter has light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material, taking into account the wavelength sensitivity characteristics of the light amount detection means. .

Further, the present invention is characterized in that the correction means is constituted by a correction mechanism that corrects the offset amount and gain of the drive circuit of the light source that outputs the light beam.

The present invention also provides a reference signal supply means in which the correction mechanism supplies a reference signal to the drive circuit, and a light amount of a light beam output from a light source based on the reference signal and a desired reference light amount related to the reference signal. The present invention is characterized by comprising a correction amount calculating means for comparing the values, calculating an offset amount and a gain correction amount of the drive circuit, and supplying the calculated offset amount and gain correction amount to the drive circuit.

Furthermore, the present invention provides that when recording an image or the like on a photosensitive material by simultaneously outputting light beams having the same or substantially the same wavelength from a plurality of light sources, the light beam has light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material. The amount of light is detected by guiding it to the light amount detection means through a filter having
Another optical vinyl is guided through the filter to the light amount detection means to detect the amount of light, and further, the offset amount and gain of the drive circuit for driving each light source are adjusted so that the amounts of light are equal. do.

[Embodiments] Next, preferred embodiments of the light beam output adjustment device and its adjustment method according to the present invention will be described in detail below with reference to the accompanying drawings.In FIG. 1, reference numeral 10 is 1 shows a main body of an image recording apparatus in which a light beam output adjustment device according to the present embodiment is incorporated. In this case, the main body part 10 is surrounded by a casing 12, and the inside thereof includes an exposure part 14, a water application part 16,
A thermal development transfer section 18 and a control section 20 for controlling these are provided. In the main body 10, image information is recorded on the photosensitive material F by a light beam output from a light emitting element, and image information is recorded on the photosensitive material F by heating the image receiving material P in a superimposed state on the photosensitive material F. The image is transferred and recorded onto the material P.

A magazine 22 for storing a photosensitive material F wound into a roll is loaded in the main body 10, and the photosensitive material F taken out from the magazine 22 is passed through a cutter 24 to the exposure section 1.
Transferred to 4. The exposure section 14 includes a drum 26 that rotates at high speed in the main scanning direction (six directions of arrows), and as shown in FIG.
The exposure head 30 is arranged close to the drum 26 and moves in the sub-scanning direction (direction of arrow B) via a wire 28.

On the support body 31 constituting the exposure head 30, six sets of two LEDs 32a to 32f are arranged at predetermined intervals in the main scanning direction.

32a, 32b, LED32c, 32d and LED3
2e and '32f simultaneously output light of different wavelengths to the photosensitive material F wound around the drum 26.

For example, L'E D32 a's 32 b irradiates the photosensitive material F with infrared light that develops a cyan (C) dye,
The LEDs 32c and 32d emit red light that causes a magenta (M') dye to develop, and the LEDs 32e and 32f irradiate yellow light that causes a yellow (Y) dye to develop.

Here, in the end of the drum 26, L E of the photosensitive material F is
On the extension of the exposure surface by D32a to 32f, light amount detection units 33a, 33b, and 33C, which constitute the light beam output adjustment device according to this embodiment, are arranged. in this case,
Each party amount detection unit 33a to 3'3C has LEDs 32a, 32
light intensity detectors 35a to 35c for detecting the light intensity of each light beam output from LED 32C 132d and LED32e, 32f, and the wavelength sensitivity of the light intensity detectors 35a to 35C in the vicinity of the wavelength of each light beam. It is composed of filters 37a to 37c having light transmission characteristics corresponding to the long-length sensitivity characteristics of the photosensitive material F, taking into account the characteristics.

The water application section 16 applies dampening water to the exposed surface of the photosensitive material F transferred from the exposure section 14 and transfers this photosensitive material F to the thermal development transfer section 18 . A tray 34 for storing a sheet-like image receiving material P is loaded in the upper part of the thermal development transfer section 18 . The image-receiving material P is sheeted by a conveying roller 36 and transferred to the thermal development transfer section 18 . In this case, the thermal development transfer section 1
At step 8, the photosensitive material F and the image receiving material P are superimposed and subjected to a heat development process and a color image transfer process.

On the other hand, a take-out tray 38 is provided on the upper surface of the casing 12, and the image-receiving material P on which the color image has been transferred is delivered to the take-out tray 38. Also, casing 1
A waste box 40 is disposed at the bottom of 2, and the photosensitive material F carried out from the thermal development transfer section 18 is stored in this waste box 40.

On the other hand, FIG. 3 is a configuration block diagram of an output adjustment circuit that constitutes the light beam output adjustment device according to the present embodiment and is incorporated in the control section 20, and an image processing circuit that is adjusted by the output adjustment circuit.

Note that this figure shows an output adjustment circuit and an image processing circuit related to the LEDs 32a and 32b, and since the circuits related to the other LEDs 32c to 32f are configured in the same manner, their explanations will be omitted.

The image processing circuit includes a line buffer 41 that stores image signals as line data for each main scanning line of the image, and a lookup table 4 that performs gradation conversion processing on the image signals output from the line buffer 41 based on a predetermined data table.
2, D/A converters 44a and 44b that convert the image signal subjected to gradation conversion processing by the lookup table 42 into an analog signal, and each D/A converter 44a, 44b.
An amplifier circuit 46 that outputs a drive current that drives the LEDs 32a and 32b based on analog signals from the LED32a and 32b.
a and 46b.

The output adjustment circuit includes the CP, U48, a ROM50 that outputs reference data to the D/A converters 44a and 44b based on instructions from the CPU48, and converts the light amount data of the light beam detected by the light amount detector 33a into digital data. An A/D converter 52 that converts the data and supplies it to the CPU 48, a buffer 54 that holds correction data calculated by Cptus based on the light amount data, and an amplifier that converts the correction data stored in the buffer 54 into an analog signal. circuit 4
D/A converters 56a and 56 that supply to 6a and 46b
It consists of b.

The image recording apparatus incorporating the light beam output adjustment device according to this embodiment is basically constructed as described above, and its operation and effects will be explained next.

First, the photosensitive material F stored in the magazine 22 is placed in the exposure section 1.
4, and when a predetermined amount has been delivered, the rear end portion is cut by a cutter 24. Next, the photosensitive material F transferred to the exposure section 14 is wound around a drum 26, and then the photosensitive material F transferred to the exposure section 14 is wound around a drum 26, and then the light-sensitive material F is wound around a drum 26, and then the photosensitive material F is wound around a drum 26, and then the photosensitive material
exposed by f.

In this case, an LED 32a is placed on the photosensitive material F.

32b and the cyan pixel by L E D32 c
.

Magenta pixels by 32d and LED32es32
A yellow pixel according to f is formed at the same time. In addition,
L'ED32a, 32bXLF, D32C.

32d and the LEDs 32e and 32f are arranged offset by a predetermined distance in the main scanning direction (six directions of arrows), and as the drum 26 rotates in the main scanning direction, cyan, magenta, and yellow colors are superimposed to produce the desired color. Colored pixels are formed. Further, the exposure head 30 is moved in the sub-scanning direction (direction of arrow B) by a wire 28 (see FIG. 2), and two pixels are simultaneously formed in this direction. As a result, a color image is two-dimensionally recorded on the photosensitive material F.

Here, in this embodiment, the LEDs 32 . High-speed recording of color images is achieved by emitting light from a to 32f simultaneously. in this case,
For example, if the light amounts or wavelengths of the light beams output from the LEDs 32a and 32b arranged in the sub-scanning direction are different, unevenness will occur in the image formed on the photosensitive material F. That is, since the density of the image formed on the photosensitive material F depends on the amount of light beam, the LED 32
If the light quantities of the light beams output from a and 32b are different, unevenness in density will occur in the sub-scanning direction of the photosensitive material F. Further, the photosensitive material F generally exhibits cyan (C), magenta (M), and yellow (Y) coloring characteristics having the wavelength sensitivity characteristics shown in FIG. 4 with respect to the wavelength of the light beam.

Therefore, even if the wavelength of the light beam output from the LED 32a and the wavelength of the light beam output from the LED 32b are different, density unevenness will occur in the image formed on the photosensitive material F.

Therefore, in this embodiment, the output adjustment circuit shown in FIG. 3 is used to adjust the L! , D32a to D32f, by adjusting the amount of light beams outputted from the D32a to D32f, a high quality image with no unevenness is formed. In this case, as shown in FIG. 5, the method for adjusting the output will be described below assuming that original beams having different wavelengths and light intensities are output from the LEDs 32a and 32b.

First, the exposure head 30 is connected to the drum 26 via the wire 28.
Move the L E D32 a to the end of the light amount detection section 3.
Direct it to the center of 3a. Note that the light transmission characteristic for the wavelength of the filter 37a attached to the light receiving surface of the light amount detector 35a constituting the light amount detector 33a is the same as that of the light amount detector 35a.
The cyan (
C) Set to correspond to the wavelength sensitivity characteristics for. That is, the increase/decrease in the sensitivity of the photosensitive material F with respect to the wavelength and the increase/decrease in the transmittance of the filter 37a with respect to the wavelength are made to correspond in the vicinity of the output wavelength of the LEDs 32a and 32b, as shown in FIG.

Next, based on a command from the CPU 48, reference image data d1 and d2 for exposing the photosensitive material F to a lower density and a higher density, respectively, are sent from the ROM 2O to the D/A converter 4.
4a. Here, when the image processing circuit including the LED32a is in an ideal state, light beams of predetermined light amounts Q1 and Q2 are output from the LED32a based on the reference image data d1 and d2. shall be.

The relationship between the image data and the amount of light beam in this case is shown by a solid line α in FIG.

Therefore, the reference image data d1 output from ROM2O
and d2 are each converted into analog signals by the D/A converter 44a and supplied to the amplifier circuit 46a, thereby generating a drive current and outputting a light beam from the LED 32a. This light beam enters the light amount detector 35a via the filter 37a and is converted into an electrical signal. Next, the electric signal is supplied to the CPU 48 by the A/D converter 52 as digital data of light quantities q1 and q2.

Here, it is assumed that the relationship between the image data and the amount of light beam output from the LED 32a is as shown by the broken line β in FIG. In this case, the CPU 48 calculates the light amounts Q1 and Q2 in the ideal state and the light amount Q obtained from the light amount detection section 33a.
By comparing l, Q2'(!:), the correction offset amount and correction gain of the amplifier circuit 46a are obtained, and these are output to the buffer 54 as correction data.Buffer 54
supplies the correction data to the amplifier circuit 46a via the D/A converter 56a. As a result, the corrected drive current is supplied to the L and ED 32a from the amplifier circuit 4aa, and light beams having desired light quantities Q1 and Q2 are obtained for the reference image data d1 and d2.

Note that if the initial amount of light emission deviates significantly from the desired amount of light, one measurement correction may not be able to sufficiently correct it within the allowable range. At this time, it is possible to improve the accuracy of correction by going through the same process once again.

When the adjustment work of the amplifier circuit 46a that controls the LED32a is completed, the exposure head 30 is then displaced so that the LED32b is directed toward the center of the light amount detection section 33a. Then, as in the previous case, ,ROM
50, the reference image data dl, d2 are transferred to the D/A converter 4.
4b and L E D3 using the amplifier circuit 46b.
2b is caused to emit light, and the amount of light is detected by the light amount detection section 33a. In this case, as shown in FIG.
A filter 37a having light transmission characteristics that takes into account the wavelength sensitivity characteristics of the light amount detector 35a and corresponds to the wavelength sensitivity characteristics of the photosensitive material F is attached. Therefore, the light amount detector 35a
The light beam output from L E D32 a and the L
A light beam from which the influence of the difference in sensitivity of the photosensitive material F due to the difference in the wavelength of the light beam outputted from the E D32 b has been removed is incident. The light beam incident on the light amount detector 35a is converted into an electrical signal and then supplied to the CP 048 via the A/D converter 52 as light amount data. Then, as in the case described above, correction data is calculated and supplied to the amplifier circuit 46b via the buffer 54 and the D'/A converter 56b. As a result, the amplifier circuit 46b (7EH offset amount and gain are corrected and L
E I) The output of 32 b is adjusted. As a result of adjusting the outputs of L E D'32'a and 32b in this way, the density of the pixel formed on the photosensitive material F for the same image signal is as shown in FIG. E D
Even if the wavelengths of the light beams output from 32a and 32b are different, they are set to be equal.

Similarly, the offset amount and gain are adjusted for the L E Ds 32c to 32f using the light amount detection units 33b and 33C. As above, LE, D32
When an image is formed on the photosensitive material F based on the desired image signal after adjusting the values a to 32f, a high quality image without unevenness can be obtained. Note that instead of using the bumper 54 and the D/A converters 56a, 56b, it is also possible to adjust the offset amount and gain of the amplifier circuits 45a, 46b using a volume or the like.

Next, the photosensitive material F on which the color image has been recorded is transferred to a drum 2.
By rotating 6 in the direction opposite to the direction of arrow A, the water is transferred to the water application section 16. The photosensitive material F transferred to the water application section 16 has its exposure surface coated with dampening water, and is sent to the thermal development transfer section 18 . On the other hand, the image-receiving material P stored in the tray 34 is conveyed into sheets by a conveying roller 36, and is overlapped with the photosensitive material F in the thermal development transfer section 18. In this case, in the thermal development transfer section 18, a color image is developed by heating the photosensitive material F, and then this color image is transferred onto the image receiving material P. After the image-receiving material P on which the color image has been transferred is separated from the photosensitive material F, it is carried out to a take-out tray 38. Further, the photosensitive material F is discharged into the waste box 40.

Note that in the embodiment described above, each of the filters 37a to 37
For example, filters 37a to 37a are provided for each light amount detector 35a to 35c.
It is also possible to configure 7c to be replaceable. In this case, a filter 3' that takes into consideration only the wavelength sensitivity characteristics of the photosensitive material F for a light intensity detector with a single wavelength sensitivity characteristic.
Since the light transmission characteristics of 7a to 37c can be set, the setting work becomes easier.

[Effects of the Invention] As described above, according to the present invention, a light beam for recording an image or the like by scanning a photosensitive material is passed through a filter having light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material. The light beam is guided to a light amount detecting means, and the output of the light beam is adjusted based on the light amount obtained from the light amount detecting means.

In this case, the light beam enters the light amount detection means as a light beam from which the wavelength sensitivity characteristics of the photosensitive material have been removed by the filter. Therefore, by adjusting the output of the light emitting elements so that the light intensity of the light beam incident on the light intensity detection means is equal for the same reference image data, the light emitting elements that simultaneously form pixels on the photosensitive material can be Differences in image density due to differences in wavelength can be corrected, making it possible to obtain extremely high-quality images without unevenness.゛This also makes it possible to simultaneously drive multiple light emitting elements that output light beams with slightly different wavelengths to form highly accurate images, increasing the tolerance for selecting the quality of the light emitting elements. However, there is also an advantage that an inexpensive image recording device can be provided.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, it is also possible to use a semiconductor laser or the like as the light emitting element. Furthermore, instead of correcting the offset amount and gain of the light source driving circuit, it is possible to consider a method of digitally correcting the image data by performing arithmetic processing on the image data itself or using a conversion table, etc., within the scope of the present invention. Of course, various improvements and changes in design are possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image recording apparatus incorporating a light beam output adjustment device according to the present invention, FIG. 2 is an explanatory diagram of the configuration of an exposure section of the image recording apparatus shown in FIG. 1, and FIG. A configuration block diagram of an output adjustment circuit and an image processing circuit incorporated in the image recording device shown in the figure, FIG. 4 is a wavelength sensitivity characteristic diagram of a photosensitive material, and FIG. 5 is applied to the light beam output adjustment device according to the present invention. A diagram showing the relationship between the wavelength and light intensity before adjusting the output of the light emitting element, FIG. 6 is a characteristic diagram of the filter in the light beam output adjustment device according to the present invention, and FIG. 7 is image data in the light beam output adjustment device according to the present invention. FIG. 8 is a diagram illustrating the density of an image formed using a light emitting element whose output is adjusted by the light beam output adjustment device according to the present invention. 10... Main body part 14... Exposure part 16.
...Water application section 18...Heat development transfer section 20
...Control unit 26...Drum 30...
Exposure head 32a-32f...LEDF・
...Photosensitive material P...Image receiving material wavelength Wavelength (nm) Image data wavelength

Claims (5)

[Claims] (1) A filter that has light transmission characteristics corresponding to the wavelength sensitivity characteristics of a photosensitive material on which an image or the like is recorded by an intensity-modulated light beam, and a light amount detection that receives a light beam through the filter and detects the amount of light. A light beam output adjusting device comprising: a correcting means for correcting the output of the light beam so that the light quantity detected by the light quantity detecting means becomes a predetermined light quantity. (2) The light beam output adjusting device according to claim 1, wherein the filter has light transmission characteristics corresponding to the wavelength sensitivity characteristics of the photosensitive material, taking into account the wavelength sensitivity characteristics of the light amount detection means. (3) The light beam output adjusting device according to claim 1, wherein the correction means comprises a correction mechanism that corrects the offset amount and gain of the drive circuit of the light source that outputs the light beam. (4) In the apparatus according to claim 3, the correction mechanism includes a reference signal supply means for supplying a reference signal to the drive circuit, and a light amount of the light beam output from the light source based on the reference signal and the reference signal. A light beam output adjustment device comprising: a correction amount calculating means for comparing the amount of light with the desired reference light amount, calculating an offset amount and a gain correction amount of the drive circuit, and supplying the calculated offset amount and gain correction amount to the drive circuit. (5) When recording images, etc. on a photosensitive material by simultaneously outputting light beams of the same or substantially the same wavelength from multiple light sources, the light beam has light transmission characteristics that correspond to the wavelength sensitivity characteristics of the photosensitive material. The light quantity is detected by guiding the light beam to the light quantity detection means through the filter, and then the other light beam is guided to the light quantity detection means through the filter to detect the light quantity, and further, the light quantity is made equal to the other light beam. A light beam output adjustment method comprising adjusting the offset amount and gain of a drive circuit that drives each light source.