JPH0618425B2 - Laser recording device - Google Patents

Description

The present invention relates to a laser recording device for recording a continuous tone image by scanning a photosensitive material with a laser beam modulated based on an image signal, and more particularly, to a laser recording device. The present invention relates to a laser recording device capable of recording a high gradation image by modulating the light intensity of a laser beam in an analog manner.

(Prior Art) Conventionally, an optical scanning recording apparatus that records an image on a photosensitive material by deflecting a light beam by an optical deflector to scan the photosensitive material has been widely put into practical use. A semiconductor laser has been conventionally used as one of means for generating a light beam in such an optical scanning recording apparatus. This semiconductor laser has a number of advantages such as smaller size, lower cost, lower power consumption, and direct modulation by changing the drive current, as compared with a gas laser or the like.

On the other hand, however, this semiconductor laser is applied to recording a continuous tone image because the light output characteristic with respect to the drive current is extremely different between the LED area (natural light emitting area) and the laser oscillation area as shown in FIG. There is a problem that it is difficult. That is, when the intensity modulation is performed using only the laser oscillation region in which the drive current-optical output characteristic is linear,
The dynamic range of light output can be at most about two digits. As is well known, it is impossible to obtain a high-quality continuous tone image with such a dynamic range.

Then, for example, JP-A-56-115077 and 56-1
No. 52372, the optical output of the semiconductor laser is kept constant, and the semiconductor laser is continuously turned on.
Attempts have also been made to record a continuous tone image by turning the scanning beam N-OFF to turn the scanning beam into pulsed light, and controlling the number or width of this pulse for each pixel to change the amount of scanning light.

However, when performing the pulse number modulation or the pulse width modulation as described above, for example, the pixel clock frequency is 1M.
In order to secure the density scale, that is, the resolution of the scanning light quantity at 10 bits (about 3 digits) at Hz, the pulse frequency must be set at a very high level of at least 1 GHz. The semiconductor laser itself turns on at this frequency.
-Although it can be turned off, a pulse count circuit or the like for controlling the number of pulses or pulse width cannot operate in response to such a high frequency, and in the end, the pixel clock frequency must be higher than the above value. It has to be lowered significantly. Therefore, the recording speed of the device must be significantly reduced.

Further, in the above method, the heat generation amount of the semiconductor laser chip changes depending on the number or width of the pulses output during the recording period of each pixel, which causes the drive current-optical output characteristics of the semiconductor laser to change. It may change and the exposure amount per pulse may fluctuate. In this case, the gradation of the recorded image is deviated, and it becomes impossible to obtain a high-quality continuous tone image.

On the other hand, as disclosed in, for example, Japanese Patent Laid-Open No. 56-71374, there has been proposed a method of recording a high gradation image by combining the above-mentioned pulse number modulation or pulse width modulation with the above-mentioned light intensity modulation. However, also in this case, as described above, the amount of heat generated by the semiconductor laser chip changes depending on the number or width of the pulses, and as a result, the amount of exposure per pulse fluctuates.

In view of the above, for example, a concentration scale of 10 bits
That is, in order to record a high gradation image of about 1024 gradations,
It is desired to perform light intensity modulation over the LED region and the laser oscillation region shown in FIG. 2 so that the dynamic range of the light output can be secured by about three digits. However, over the above two regions, the driving current vs. optical output characteristic of the semiconductor laser is naturally not linear, so that a high gradation image can be recorded easily and accurately at a constant density interval with respect to a certain change in the image signal. In order to make the image density controllable, it is necessary to compensate for the above characteristics by some method and linearly change the relationship between the emission level command signal of the semiconductor laser and the optical output.

As a circuit for linearizing the relationship between the light emission level command signal of the semiconductor laser and the light output, conventionally, the light intensity of the laser beam is detected, and a feedback signal corresponding to the detected light intensity is sent as a light emission level command of the semiconductor laser. An optical output stabilizing circuit (hereinafter referred to as an APC circuit) for feeding back a signal is known. FIG. 3 shows an example of the APC circuit, and the APC circuit will be described below with reference to FIG. A light emission level command signal Vref that commands the light emission intensity of the semiconductor laser 1 is input to a voltage-current conversion amplifier 3 through an addition point 2, and the amplifier 3 supplies a drive current proportional to the command signal Vref to the semiconductor laser 1. . The light beam 4 emitted forward from the semiconductor laser 1 is used for scanning the photosensitive material through a scanning optical system (not shown). On the other hand, the intensity of the light beam 5 emitted to the rear side of the semiconductor laser 1 is detected by, for example, a pin photodiode 6 for light amount monitoring installed in the case of the semiconductor laser. The intensity of the light beam 5 thus detected is proportional to the intensity of the light beam 4 actually used for image recording. The output current of the photodiode 6, which indicates the intensity of the light beam 5, that is, the intensity of the light beam 4, is
Feedback signal (voltage signal) by the current-voltage conversion amplifier 7.
Converted to Vpd, the feedback signal Vpd is input to the addition point 2 described above. From this addition point 2, a deviation signal Ve indicating the deviation between the emission level command signal Vref and the feedback signal Vpd is output, and the deviation signal Ve is converted into a current by the voltage-current conversion amplifier 3 and the semiconductor laser 1 To drive.

If ideal linear compensation is performed in the above APC circuit, the intensity of the light beam 5 is proportional to the emission level command signal Vref. That is, the intensity (light output to the semiconductor laser 1) Pf of the light beam 4 used for image recording is proportional to the emission level command signal Vref. The solid line in FIG. 4 shows this ideal relationship.

(Problems to be Solved by the Invention) It is relatively easy to drive and control a semiconductor laser so that the light intensity Pf is always at a constant level using the APC circuit as described above. It is difficult to obtain the characteristics shown by the solid line in FIG. 4 when the semiconductor laser is driven by changing the emission level command signal Vref at high speed in an analog manner to record a continuous tone image. In particular,
As described above, when the pixel clock frequency is set to about 1 MHz and a high gradation image of a density scale of about 10 bits is recorded, it is very difficult.

The reason will be described below. The drive current vs. optical output characteristic of the semiconductor laser 1 inserted in the third system is extremely non-linear as shown in FIG. In other words, the differential quantum efficiency, which is the gain of the semiconductor laser alone, changes greatly in the LED region and the laser oscillation region as shown in logarithm as shown in FIG. 5, so that the characteristics shown by the solid line in FIG. 4 are obtained. Therefore, it is necessary to make the loop gain of the system of FIG. 3 very large. The curve shown by the broken line in FIG. 4 shows an example of the emission level command signal vs. optical output characteristic of the semiconductor laser which changes according to the loop gain, and as shown in the figure, the characteristic close to the ideal characteristic is shown by the solid line. In order to obtain it, a high gain of about 60 dB is required.

The characteristic shown in FIG. 4 is that the emission level command signal Vref
Is a very low frequency signal close to direct current, but when the command signal Vref is a high frequency signal,
Yet another problem arises. Hereinafter, this point will be described. FIG. 6 shows the case temperature dependence of the drive current vs. optical output characteristics of the semiconductor laser shown in FIG. As shown in the figure, the optical output of the semiconductor laser decreases as the case temperature increases if the drive current is constant. Generally, when a semiconductor laser is applied to a laser recording device or the like, control is performed to keep the case temperature constant, but transient temperature change of the laser diode chip that occurs when a drive current is applied to the semiconductor laser. It is absolutely impossible to control even this. That is, when a stepwise drive current is applied to the semiconductor laser as shown in FIG. 7 (1), the temperature of the laser diode chip is controlled by the case temperature stabilization control as shown in FIG. 7 (2). It transiently changes until it reaches a steady state, and as a result, the optical output of the semiconductor laser fluctuates as shown in FIG. 7C according to the characteristics of FIG. This is known as the droop characteristic of a semiconductor laser. In the APC circuit of FIG. 3, it is known that the loop gain of about 10 dB is required to correct the non-linearity of the laser drive current vs. optical output characteristic due to the droop characteristic. When a signal from a low frequency to a high frequency (for example, 1 MHz) is used as Vref, in order to obtain the emission level command signal-optical output characteristic (linearity) close to the solid line in FIG. 4 while maintaining high response. , 60 in the laser oscillation region
A total loop gain of about 70 dB is required together with dB. At present, it is almost impossible to realize such a high-speed, high-gain APC circuit.

Therefore, according to the present invention, the semiconductor laser emission level command signal vs. optical output characteristic can be made linear from the LED region to the laser oscillation region without using the high gain APC circuit as described above. An object of the present invention is to provide a laser recording device capable of recording a high gradation image at high speed by intensity modulation.

(Means for Solving Problems) A laser recording apparatus of the present invention includes a semiconductor laser, a beam scanning system for scanning a light beam emitted from the semiconductor laser on a photosensitive material, and an emission level corresponding to an image signal. A laser operation control circuit for generating a command signal and controlling the drive current of the semiconductor laser based on the command signal to modulate the light intensity of the laser beam; And the optical output of the semiconductor laser based on the corrected signal, by correcting the emission level command signal so as to compensate the non-linearity of the drive current vs. optical output characteristic of the semiconductor laser.
It is characterized in that a correction table for linearizing the relationship of the light emission level command signal before correction is provided.

(Operation) If the emission level command signal of the semiconductor laser is corrected by the correction table as described above, the emission level command signal before correction and the semiconductor laser light output are shown in FIG. 4 even if the gain of the APC circuit is low. It is possible to obtain a light output characteristic close to the ideal characteristic indicated by the solid line.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows a laser recording apparatus according to the first embodiment of the present invention. The image signal generator 10 generates an image signal S1 carrying a continuous tone image. The image signal S1 is, for example, a digital signal indicating a continuous tone image of a 10-bit density scale. The image signal generator 10 switches signals for one main scanning line based on a line clock S2 described later, and outputs an image signal S1 for each pixel based on a pixel clock S3. In this example, the pixel clock frequency is 1 MHz, in other words, one pixel recording time is 1 μsec.
(Seconds).

The above-mentioned image signal S1 is passed through the multiplexer 11 to the RAM
The correction table 40 consisting of is subjected to a later-described correction and converted into, for example, a 16-bit emission level command signal S5. This emission level command signal S5 is a multiplexer
It is input to the D / day converter 16 via 15 and converted into a light emission level command signal Vref composed of an analog voltage signal. This light emission level command signal Vref is supplied to the APC circuit 8
Is input to the addition point 2 of. The addition point 2, the voltage-current conversion amplifier 3, the semiconductor laser 1, the photodiode 6, and the current-voltage conversion amplifier 7 of the APC circuit 8 are the third described above.
The semiconductor laser 1 emits a light beam 4 having an intensity corresponding to the emission level command signal Vref (that is, corresponding to the image signal S1). This light beam 4 is collimator lens 17
To be a parallel beam, which is then incident on an optical deflector 18 such as a polygon mirror and reflected and deflected there. The light beam 4 thus deflected is passed through a focusing lens 19 which is usually an fθ lens to be focused on a minute spot on the photosensitive material 20, and the photosensitive material 20 is scanned (main scanning) in the X direction. The photosensitive material 20 is transferred by a transfer means (not shown).
The light beam 4 is transferred in the Y direction which is substantially perpendicular to the main scanning direction X, whereby the light beam 4 is sub-scanned. In this way, the photosensitive material 20 is two-dimensionally scanned by the light beam 4 and exposed. Since the light beam 4 is intensity-modulated based on the image signal S1 as described above, the continuous tone image carried by the image signal S1 is recorded as a photographic latent image on the photosensitive material 20. When the light beam 4 scans the photosensitive material 20 as described above, the photodetector 21 detects that the beam 4 has passed the starting point of the main scanning, and the start point detection signal output by the photodetector 21. S6 is input to the clock generator 36. The clock generator 36 outputs the line clock S2 and the pixel clock S described above in synchronization with the input timing of the start point detection signal S6.

Next, the light-sensitive material 20 is passed through a developing machine 22, where it is subjected to development processing. As a result, the continuous tone image is recorded on the photosensitive material 20 as a visible image.

Therefore, the correction of the image signal S1 in the correction table 40 described above will be described. The correction table 40 is a gradation correction table 12, an inverse log conversion table 13, and a correction table (hereinafter referred to as a VP characteristic correction table) 14 for linearly correcting the emission level command signal-optical output characteristic of the semiconductor laser 1. The gradation correction table 12 consisting of
And a known one for correcting the gradation characteristic of the development processing system. The gradation correction table 12 may have a fixed correction characteristic, but in the present embodiment, the gradation characteristic of the photosensitive material 20 changes from lot to lot, or development in the developing machine 22 is performed. In consideration of the liquid characteristics changing with time, the correction characteristics can be appropriately modified in accordance with the actual gradation characteristics. That is, the test pattern generation circuit 26
From which a test pattern signal S4 carrying an image density of several steps (for example, 16 steps) on the photosensitive material 20 is output, and the signal S4 is input to the multiplexer 11.
At this time, the multiplexer 11 uses the image signal S1 as described above.
Is switched to the correction table 40, and the test pattern signal S4 is input to the correction table 40. The semiconductor laser 1 is driven based on this test pattern signal S4 as described above, and thus the light beam 4 is intensity-modulated. As a result, 16 step wedges (test patterns) whose densities change stepwise are recorded as photographic latent images on the photosensitive material 20. The photosensitive material 20 is sent to the developing machine 22, and the step wedge is developed. After development, the photosensitive material 20 is set in the densitometer 23, and the optical density of each of the step wedges is measured. The optical density thus measured is input to the density value input means 24 in association with each step wedge, and the density value input means 24 outputs a density signal S7 indicating the optical density of each step wedge. The density signal S7 is input to the table creating means 37, and the table creating means 37 determines a predetermined image signal S based on the density signal S7 and the test pattern signal S4.
A gradation correction table that produces a predetermined image density with a value of 1 is created. As described above, the gradation correction table is such that the image signal values of about 16 steps are made to correspond to the respective predetermined image density values. The data S8 indicating the gradation correction table is input to the data interpolating means 38, and the interpolation processing is performed here to obtain the gradation correction table that can correspond to the image signal S1 of 1024 steps (= 10 bits). The above-described gradation correction table 12 is formed based on the data S9 indicating this gradation correction table.

When recording an image based on the image signal S1, the multiplexer
The image signal S input to the gradation correction table 12 via 11
1 is converted into a signal S1 'by the gradation correction table 12, and then converted into a light emission level command signal S1 "by the inverse log conversion table 13.

Next, the VP characteristic correction table 14 will be described. As described above, even if the feedback signal Vpd is fed back to the addition point 2 in the APC circuit 8, the ideal relationship between the emission level command signal and the intensity of the light beam 4 (the relationship shown by the solid line in FIG. 4) is obtained. ) Is difficult. The VP characteristic correction table 14 is provided to obtain the above ideal relationship. That is, the light emission level command signal Vref
8 and the optical output of the semiconductor laser 1 is a straight line indicated by a in FIG. 8 and the actual relation is a curve indicated by b in FIG. 8, the VP characteristic correction table 14 shows Assuming that the voltage value when the level command signal S1 ″ is directly D / A converted is Vin, the voltage value Vin is formed to be converted to a value V. That is, the light emission level command signal Vref If the value is Vin,
Only the light intensity of P ′ can be obtained, but if the above conversion is performed, the light intensity of P _O can be obtained for the voltage value Vin.
That is, the voltage value V corresponding to the light emission level command signal S1 ″
The relationship between in and the optical output Pf is linear.

With this configuration, the density of the photosensitive material 20 can be controlled at equal intervals by changing the image signal S1 by a predetermined amount. The characteristic curve b in FIG. 8 is obtained when the semiconductor laser 1 is driven over the LED region and the laser oscillation region as described above.
Since the optical output dynamic range of the order of magnitude is secured,
As described above, it becomes possible to easily and highly accurately record a high gradation image of about 1024 steps.

As described above, the non-linearity of the emission level command signal-laser light output characteristic due to the non-linear drive current-optical output characteristic of the semiconductor laser 1 is linearly corrected by the VP characteristic correction table 14. For example, in the loop gain of the system in which the addition point 2 of the APC circuit 8, the voltage-current conversion amplifier 3, the semiconductor laser 1, the photodiode 6, and the addition point 2 from the current-voltage conversion amplifier are returned to correct the above non-linearity. You no longer need to include the gain you need. That is, this loop gain corrects a deviation from the drive current-optical output characteristic of the semiconductor laser 1 due to a transient temperature change that occurs during the operation of the semiconductor laser 1 or an error in the case temperature constant control of the semiconductor laser 1. Furthermore, it is sufficient to secure as much as necessary to correct the drift of the amplifier or the like. Specifically, for example, the pixel clock frequency is 1 MH
In the state where the semiconductor laser 1 is operating at a light output of 3 mW at z, it is sufficient if the loop gain is secured at about 30 dB. This level of loop gain can be easily secured with the current state of the art.

Next, the creation of the VP characteristic correction table 14 will be described. A table creating device 35 can be appropriately connected to the device of FIG. This table making device 35
Is composed of a test signal generating circuit 27, a table creating circuit 28 and a memory 29. When the VP characteristic correction table 14 is created, the test signal generating circuit 27 outputs the level-variable digital test signal S10 and the multiplexer 15
Entered in. At this time, the multiplexer 15 switches the emission level command signal S5 from the state at the time of image recording for sending the light emission level command signal S5 to the D / A converter 16 as described above, and outputs the test signal S10 to D / A.
It is ready to be sent to the A converter 16. Also table making circuit
28 is connected so that the feedback signal Vpd output from the current-voltage conversion amplifier 7 of the APC circuit 8 is input. The test signal S10 is output so that the level is increased or decreased stepwise. And at this time the table creation circuit 28
First generates a reference signal corresponding to the lowest optical output from the built-in level variable signal generator, and compares the reference signal with the feedback signal Vpd. This reference signal has the voltage value Vin shown in FIG. The table creating circuit 28 then outputs the test signal S when these two signals match.
Latch the value of 10. This latched test signal S10
Since the voltage value shown by corresponds to the voltage value V in FIG. 8, the relationship between the voltage values Vin and V can be understood.
The table creating circuit 28 changes the value of the reference signal in 1024 ways, and obtains the relationship between the voltage values Vin and V in each case. As a result, as described above, the correction table for converting the voltage value Vin of 1024 steps into V is created.
The correction table thus created is once stored in the memory 29 and then set as the VP characteristic correction table 14. After creating the VP characteristic correction table 14 in this way,
The table creating device 35 is separated from the APC circuit 8.

Note that, as described above, the relationship between the voltage values Vin and V corresponding to all the image densities is obtained one by one, and the voltage value Vin is the same as in the case of creating the gradation correction table 12 described above.
The relationship between V and V may be obtained only in some main cases, and the data may be interpolated to create the VP characteristic correction table 14. The VP characteristic correction table 14 can also be created by calculation from the VP characteristic of the semiconductor laser. Furthermore, gradation correction table 1
2. The inverse log conversion table 13 and the VP characteristic correction table 14 may be formed as a single correction table by including all the respective conversion characteristics, or they may be configured separately. Good.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 9, elements that are the same as the elements in FIG. 1 are given the same numbers, and explanations thereof are omitted (the same applies hereinafter). Further, although FIG. 9 shows only the portion of the laser operation control circuit, the portions (not shown) such as the light beam scanning system in this apparatus are formed in the same manner as in the apparatus of FIG. In the device of the second embodiment, the emission level command signal S1 ″ output from the inverse log conversion table 13 is directly passed through the multiplexer 15 to D
It is input to the / A converter 16. On the other hand, the image signal S
1 ″ is branched and input to the VP characteristic correction table 44. This VP characteristic correction table 44 is the V of the apparatus of FIG.
Unlike the -P characteristic correction table 14, it is formed so as to obtain the difference ΔV between the voltage values V and Vin in FIG. The digital signal S5 'indicating this voltage difference ΔV is D /
The signal is passed through the A converter 45, converted into an analog signal, and added to the voltage value Vin (corresponding to the light emission level command signal S1 ″) at the addition point 2. By doing so, in the end, FIG. This is the same as inputting the signal of the voltage value V as the emission level command signal Vref to the addition point 2 as in the device of (1), and the same effect as described above can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. In the apparatus of FIG. 10, the light emission level command signal S1 ″ is branched and input to the VP characteristic correction table 44, where the correction as described above is performed, and the obtained signal S5 ′ is D / A converted. It is formed in the same way as the device of Fig. 9 until it is converted to analog in the converter 45. However, the voltage signal ΔV output from the D / A converter 45 is not input to the addition point 2 and the voltage- The current Δi is passed through the current conversion amplifier 46. This current Δi is the current Δi.
At the addition point 47 in the subsequent stage of the voltage-current conversion amplifier 3 of
The deviation signal Ve is added to the converted driving current. In the device of the third embodiment, the voltage signal Δ
It is different from the device of the second embodiment in that V is not input to the APC circuit 8 as it is, but is converted to a current Δi and then input to the APC circuit 8. Therefore, in this case also, in the device of the first embodiment, The same effect can be obtained.

(Effects of the Invention) As described in detail above, in the laser recording apparatus of the present invention, the nonlinearity of the emission level command signal vs. laser light output characteristic due to the nonlinearity of the driving current vs. optical output characteristic of the semiconductor laser is considered. Since the correction is provided by a correction table provided separately from the semiconductor laser light output stabilizing circuit, the loop gain of the closed loop configured by the light output stabilizing circuit is a low value that can be sufficiently realized at the current technical level. Even if it is set to, the relationship between the light emission level command signal and the semiconductor laser light output is maintained while maintaining high response.
It can be made linear over the D region and the laser oscillation region. Therefore, according to the apparatus of the present invention, the image density can be controlled at equal density intervals by changing the image signal by a predetermined amount, and the light output dynamic range of the semiconductor laser, that is, the exposure amount of the photosensitive material can be spread over a wide range of about three digits. Since this can be ensured, it is possible to record a continuous tone image of extremely high gradation with a density resolution of about 10 bits at high speed and precisely.

Further, according to the present invention, when a different photosensitive material whose characteristics do not change even when the semiconductor laser is replaced due to a failure or the like is used, gradation correction can be easily performed by substituting a correction table suitable for the photosensitive material. Such an effect can also be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a laser recording apparatus according to a first embodiment of the present invention, FIG. 2 is a graph showing driving current vs. optical output characteristics of a semiconductor laser, and FIG. 3 is an example of a semiconductor laser optical output stabilizing circuit. 4 is a graph showing the relationship between the emission level command signal and the semiconductor laser light output, FIG. 5 is a graph showing the relationship between the semiconductor laser light output and the differential quantum efficiency, and FIG. 6 is a semiconductor. FIG. 7 is a graph showing the droop characteristic of the semiconductor laser, and FIG. 8 is a graph showing the operation of the VP characteristic correction table in the device of the present invention. 9 is a block diagram showing a semiconductor laser operation control circuit of a laser recording apparatus according to a second embodiment of the present invention, and FIG. 10 is a semiconductor laser operation control circuit of a laser recording apparatus according to a third embodiment of the present invention. Is a block diagram showing the. 1 ... semiconductor laser, 2,47 ... adding point 3,46 ... voltage-current conversion amplifier 4,5 ... light beam, 6 ... photodiode 7 ... current-voltage conversion amplifier 8 ... APC circuit, 10 …… Image signal generator 14, 44 …… VP characteristic correction table 16, 45 …… D / A converter, 17 …… Collimator lens 18 …… Optical deflector, 19 …… Focusing lens 20 …… Photosensitive Material 35 ... Table preparation device 40 ... Correction table, S1 ... Image signal S1 ″ ... Emission level command signal before correction Vref ... Emission level command signal, Vpd ... Feedback signal Ve ... Deviation signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 59-128865 (JP, A) JP 61-230467 (JP, A) JP 60-233978 (JP, A)

Claims (4)

[Claims] 1. A semiconductor laser emitting a light beam, a beam scanning system for scanning the light beam on a photosensitive material, an emission level command signal corresponding to an image signal, and based on the signal, a semiconductor laser of the semiconductor laser. In a laser recording device having a laser operation control circuit that controls a drive current to modulate the intensity of the light beam, the laser operation control circuit detects the intensity of the light beam and responds to the detected light intensity. A light output stabilizing circuit for feeding back a feedback signal to the light emission level command signal, and correcting the light emission level command signal so as to compensate for the non-linearity of the drive current vs. light output characteristics of the semiconductor laser, and after the correction And a correction table for linearizing the relationship between the light output of the semiconductor laser based on the signal and the emission level command signal before correction. Recording device. 2. The laser recording apparatus according to claim 1, wherein the correction table is arranged in a stage preceding the optical output stabilizing circuit. 3. The correction table is arranged in a path branched from the path of the light emission level command signal to obtain a correction amount of the light emission level command signal, and a correction signal indicating the correction amount is emitted. The laser recording device according to claim 1, wherein the laser recording device is added to the level command signal. 4. The correction table is arranged on a path branched from the path of the light emission level command signal, the correction amount of the light emission level command signal is obtained, and a current corresponding to the correction amount is output. 2. The laser recording device according to claim 1, wherein the current is added to the semiconductor laser drive current.