JP2004223908A - Image recorder and image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recorder and an image recording method capable of producing an image having high image quality while shortening the printing time. <P>SOLUTION: In the initialization immediately after turn on power, light is emitted continuously from an LD and the quantity of light is regulated by increasing the operating current gradually to reach a target quantity of light P<SB>O</SB>and storing an LD operating current I<SB>CW</SB>corresponding to the target quantity of light P<SB>O</SB>. While emitting a pulse light from the LD with an LD operating current I<SB>OS</SB>lower by a specified level than the LD operating current I<SB>CW</SB>similarly to the case of image output, a starting point is detected and the quantity of light is regulated (APC control) and then an LD operating current I<SB>PS</SB>corresponding to the target quantity of light is stored for stand-by. At the time of print sequence, an image is outputted while updating the LD operating current I<SB>PS</SB>by performing APC control using the LD operating current I<SB>PS</SB>stored at stand-by. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image recording apparatus and an image recording method, and more particularly to an image recording apparatus and an image recording method for recording an image by scanning a recording medium with laser light emitted from a semiconductor laser.
[0002]
[Prior art]
In optical scanning of an image recording apparatus that records various information such as image information by scanning a light beam on a recording medium, laser light emitted from a semiconductor laser is used as a scanning light beam.
[0003]
As shown in FIG. 9, the semiconductor laser has an operating environment temperature (T ₁ , T ₂ , T ₃ ) Changes the optical output with respect to the drive current. Therefore, in general, APC (Auto Power Control) control is performed in which the laser light emitted from the semiconductor laser is detected and the semiconductor laser is driven so that the detected light amount becomes a predetermined target light amount. Done.
[0004]
Further, as shown in FIG. 10, when the image is written, the semiconductor laser is driven first after adjusting the light amount immediately after the power is turned on. In the light amount adjustment, the light amount is raised so that the light amount becomes the target light amount continuously, and then, as a standby, the start point is detected by scanning several times, and APC control is performed during this time. Similarly, at the time of image recording (printing), image output is performed after light amount adjustment and standby.
[0005]
When performing standby after performing this light amount adjustment, as shown in FIG. 11, the target light amount P obtained during the light amount adjustment is shown. _O LD operating current I _CW Is the initial LD drive current during standby, the semiconductor laser is not sufficiently warmed, and as shown in the lower side of FIG. 11, the light output becomes large, which may destroy the semiconductor laser. As shown in FIG. 10, the LD operating current I _CW LD operating current I smaller than _OS The LD operating current is gradually increased so that the target light quantity is obtained, and the LD operating current I becomes the target light quantity. _PS Like to get.
[0006]
In addition, when performing continuous printing, the amount of light of the semiconductor laser is not stable, so as shown in FIG. 10, the amount of light is increased, as shown in FIG. 10, starting up the amount of light → standby → printing → starting up the amount of light → standby → printing. The standby and print cycles are repeated.
[0007]
Thereby, in each print, it is possible to stably record an image and to obtain a high-quality print.
[0008]
In addition, since the APC control described above takes time when a plurality of semiconductor lasers are used, various proposals for reducing the time have been made. (For example, Patent Documents 1 to 4).
[0009]
[Patent Document 1]
Japanese Patent No. 2941873
[Patent Document 2]
Japanese Patent No. 2918939
[Patent Document 3]
Japanese Patent No. 2905229
[Patent Document 4]
Japanese Patent Laid-Open No. 11-40875
[0010]
[Problems to be solved by the invention]
However, in conventional techniques such as APC control, since the light amount is gradually increased from 0 to the target light amount when the light amount is raised, it takes time, and in standby, the actual image output control for starting point detection is performed. There is a problem that the time for one line takes a plurality of lines.
[0011]
In addition, since the temperature state of the semiconductor laser changes in each of the light amount rising, standby, and printing states, the APC control amount is large and it takes time to reach the target value. Furthermore, when APC control is performed, the temperature of the semiconductor laser is often not controlled, and the APC control amount tends to increase.
[0012]
Here, in order to shorten the printing time, when printing is started without simply starting up the amount of light or standby, due to the light output characteristics due to the temperature of the semiconductor laser, more light than expected is output immediately after the start of image output, This causes not only unevenness on the image and image quality, but also causes the semiconductor laser to be driven exceeding the maximum rating of the optical output determined by the specification, thereby degrading the semiconductor laser.
[0013]
In addition, even when a cycle consisting of light intensity startup, standby, and printing is performed, it is possible to set the operating current value when starting with continuous light emission as it is in the standby state or during printing. Regardless of the difference, the temperature of the semiconductor laser changes (downward) due to the light output characteristics depending on the temperature of the semiconductor laser. As a result, unevenness in the image is generated and the image quality is deteriorated. In addition, the semiconductor laser is driven beyond the maximum rating determined in the specification, and the semiconductor laser may be deteriorated.
[0014]
On the other hand, in the techniques described in Patent Documents 1 to 4, there is no description of the driving cycle of the semiconductor laser in the cycle from the light quantity start-up to printing, and in the case of continuous printing, as described above, for each print of each page. Since it is considered that the light quantity rise and standby cycles are repeated, it takes time to drive the semiconductor laser.
[0015]
The present invention has been made to solve the above problems, and an object of the present invention is to provide an image recording apparatus and an image recording method capable of reducing a printing time and obtaining a high-quality image. .
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is directed to a semiconductor laser that emits laser light, detection means that detects the amount of laser light emitted from the semiconductor laser, and the semiconductor laser when power is turned on. Are continuously emitted, and a light amount control means for driving and controlling the semiconductor laser so that a light quantity detected by the detection means becomes a predetermined target light quantity, and the target at the time of driving the semiconductor laser by the light quantity control means. The semiconductor laser is pulsed to emit light based on the driving amount at the time of light quantity, and the semiconductor laser is driven and controlled so as to obtain the target light quantity, and the semiconductor laser is driven by the standby control means when the semiconductor laser is driven. Storage means for storing the drive amount at the time of the target light amount, and at the time of the target light amount stored in the storage means at the time of image recording Image recording means for recording an image based on the amount of movement, driving and adjusting the semiconductor laser so as to obtain the target light amount, and storing and updating the drive amount at the target light amount stored in the storage means. It is characterized by that.
[0017]
According to the first aspect of the present invention, the semiconductor laser emits laser light, and the amount of light of the laser light is detected by the detecting means.
[0018]
As described above, since the light output of the semiconductor laser changes depending on the temperature environment, the light amount control means causes the semiconductor laser to emit light continuously when the power is turned on, and the light quantity detected by the detection means becomes a predetermined target light quantity. As described above, the semiconductor laser is driven and controlled. Further, the standby control unit emits a pulse of the semiconductor laser based on the driving amount at the target light amount when the semiconductor laser is driven by the light amount control unit, and the driving amount of the semiconductor laser is controlled so that the target light amount is also obtained here. . In this way, by causing the semiconductor laser to emit light in pulses, the temperature of the semiconductor laser can be made the same as that at the time of image recording so that the temperature of the semiconductor laser becomes the same temperature as at the time of actual image recording, At the time of image recording, the light output can be stabilized and a high-quality image can be obtained.
[0019]
Then, the drive amount at this time is stored in the storage means, and at the time of image recording, image recording is performed by the image recording means based on the drive amount of the storage. That is, since the image is recorded by the semiconductor laser adjusted to the target light amount, the image can be recorded with a stable light amount, and a high-quality image can be obtained.
[0020]
Furthermore, since the semiconductor laser is driven and adjusted so that the target light amount is also obtained in the image recording means, the light amount of the semiconductor laser is adjusted as needed. Since the drive amount at the time of the adjustment is stored and updated in the storage means, the light amount can be adjusted as needed, image recording can be performed with a stable light amount, and a high-quality image can be obtained.
[0021]
According to the first aspect of the present invention, it is possible to obtain a high-quality image without performing light amount adjustment and standby control again as in the prior art during image recording. it can.
[0022]
The standby control means causes the semiconductor laser to emit pulses with a drive amount that is a predetermined amount smaller than the drive amount at the target light amount when the semiconductor laser is driven by the light amount control means. By controlling the driving of the semiconductor laser so as to achieve the target light amount, it is possible to prevent light emission above the rating of the semiconductor laser.
[0023]
Further, as described above, the standby control means causes the semiconductor laser to emit light so as to emit light in pulses during image recording, so that the temperature of the semiconductor laser is adjusted during actual image recording as described above. Thus, the temperature of the semiconductor laser can be made the same as that at the time of image recording, the light output can be stabilized at the time of image recording, and a high-quality image can be obtained. For example, by emitting a pulse of a semiconductor laser based on dummy image data in the absence of a recording material or the like, it is possible to emit a pulse as in the case of image recording.
[0024]
Further, as in the invention described in claim 4, when continuously recording images, the image recording unit records an image based on the driving amount of the semiconductor laser stored in the storage unit, By adjusting and driving the semiconductor laser so that the drive amount becomes equal, and the drive amount at the target light amount stored in the storage means is stored and updated, the light amount adjustment and standby are always performed even during continuous printing as in the conventional technique. Compared to the above, the printing time during continuous printing can be greatly shortened.
[0025]
The invention according to any one of claims 1 to 4 further includes a heating and cooling means for adjusting the temperature by heating or cooling the semiconductor laser, as in the invention according to claim 5. May be. By further providing the heating and cooling means in this way, the semiconductor laser can emit light more stably, so that a high-quality image can be obtained.
[0026]
According to the sixth aspect of the invention, when the power is turned on, the semiconductor laser continuously emits light, the laser light emitted from the semiconductor laser is detected, and the semiconductor laser is driven so that the detected light amount becomes a predetermined target light amount. Based on the light amount control step to be controlled and the driving amount of the semiconductor laser at the target light amount in the light amount control step, the semiconductor laser is driven to control the pulse so that the detected light amount becomes the target light amount. A standby step, a storage step for storing a driving amount of the semiconductor laser at the target light amount in the standby step, and an image recording based on the driving amount at the target light amount stored in the storage step, While recording an image, the semiconductor laser is driven and adjusted so that the detected light amount becomes the target light amount. An image recording step of storing and updating the driving amount at the time 憶 been the target quantity, and comprising a.
[0027]
According to the invention described in claim 6, in the light amount control step, when the power is turned on, the semiconductor laser is continuously emitted to detect the light amount, and the semiconductor laser is driven so that the detected light amount becomes a predetermined target value. Control. In the standby step, the semiconductor laser is driven and controlled so that the semiconductor laser emits pulses based on the driving amount of the semiconductor laser at the target light amount in the light amount control step so that the detected light amount becomes the target light amount. In this way, by causing the semiconductor laser to emit pulses, the temperature of the semiconductor laser becomes the same as that at the time of actual image recording, and the temperature of the semiconductor laser can be set to the same state as at the time of image recording. The light output can be stabilized and a high-quality image can be obtained.
[0028]
The drive amount at this time is stored in the storage step, and at the time of image recording, image recording is performed in the image recording step based on the stored drive amount. That is, since the image is recorded by the semiconductor laser adjusted to the target light amount, the image can be recorded with a stable light amount, and a high-quality image can be obtained.
[0029]
Further, in the image recording step, the semiconductor laser is driven and adjusted so as to obtain the target light amount, so that the light amount of the semiconductor laser is adjusted as needed. Then, since the drive amount at the target light amount stored in the storing step is stored and updated from the adjustment, the light amount is adjusted at any time, an image can be recorded with a stable light amount, and a high-quality image can be obtained.
[0030]
Further, in the invention according to the sixth aspect, when recording an image, a high-quality image can be obtained without performing light amount adjustment and standby control again as in the prior art, so that the printing time can be shortened. Can do.
[0031]
In the standby step, as in the invention according to claim 7, the semiconductor laser is pulse-emitted with a drive amount smaller than the drive amount at the target light amount at the time of driving the semiconductor laser in the light amount control step, By driving and controlling the semiconductor laser so as to achieve the target light amount, it is possible to prevent light emission above the rating of the semiconductor laser.
[0032]
In the standby step, as described above, the semiconductor laser is caused to emit light so as to emit light in pulses during image recording. The temperature becomes the same, and the temperature of the semiconductor laser can be made the same as that at the time of image recording. At the time of image recording, the light output can be stabilized and a high-quality image can be obtained. For example, by emitting a pulse of a semiconductor laser based on dummy image data in the absence of a recording material or the like, it is possible to emit a pulse as in the case of image recording.
[0033]
Further, as in the invention according to claim 9, when continuously recording images, the image recording step records an image based on the driving amount at the target light amount stored in the storing step, By adjusting the drive of the semiconductor laser so that it becomes the target light amount and storing and updating the drive amount at the target light amount stored in the storage step, the light amount adjustment and standby are always performed even during continuous printing as in the conventional technology In comparison, the printing time for continuous printing can be greatly reduced.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, the present invention is applied to a laser printer applicable to a digital laboratory system or the like.
[0035]
FIG. 1 shows an optical system of a laser printer according to an embodiment of the present invention. As shown in FIG. 1, the laser printer includes three laser light sources 211R, 211G, and 211B. The laser light source 211R is configured by a semiconductor laser (LD) that emits laser light (hereinafter referred to as R laser light) having a red (R) wavelength (for example, 685 nm). The laser light source 211G is configured by a semiconductor laser (LD) that emits laser light (hereinafter referred to as G laser light) having a green (G) wavelength (for example, 532 nm). The laser light source 211B is configured by an LD that emits laser light (hereinafter referred to as B laser light) having a blue (B) wavelength (for example, 440 nm). In addition, it is good also as a structure provided with the wavelength conversion element (SHG) in the laser beam emission side of a semiconductor laser.
[0036]
A collimator lens 212, a collimator lens 213, and a cylindrical lens 217 are sequentially arranged on the laser light emission side of each laser light source 211R, 211G, 211B, and the laser light emitted from each laser light source 211R, 211G, 211B is collimated. The lens 213 converts the light into substantially parallel light, irradiates the reflecting surface of the polygon mirror 218 via the cylindrical lens 217, and reflects the reflected light by the polygon mirror 218.
[0037]
The three R, G, and B laser beams reflected by the polygon mirror 218 are sequentially transmitted through the fθ lens 220 and the cylindrical lens 221, reflected by the cylindrical mirror 222, and then reflected substantially vertically downward by the folding mirror 223. Then, the printing paper 224 is irradiated through the opening 226. Alternatively, the folding mirror 223 may be omitted, and the photographic paper 224 may be irradiated by being directly reflected substantially vertically downward by the cylindrical mirror 222. Note that the photographic paper 224 has sensitivity to C, M, and Y with respect to R, G, and B light, respectively.
[0038]
The polygon mirror 218 rotates in the direction of arrow A in FIG. 1, whereby the laser beam moves in the direction of arrow B in FIG. 1, whereby main scanning is performed, and the photographic paper 224 moves in the direction of arrow C in FIG. By doing so, sub-scanning is performed.
[0039]
On the other hand, in the vicinity of the scanning exposure start position side on the photographic printing paper 224, an optical synchronization detection means 228 for detecting the laser light that has reached through the opening 226 is disposed. In the present embodiment, the signal output from the optical synchronization detection means 228 is normally at a low level and is configured to be at a high level only when a laser beam is detected.
[0040]
Next, the functional configuration of the laser printer configured as described above will be described with reference to FIG.
[0041]
As shown in FIG. 2, the laser printer includes image data memories 12R, 12G, and 12B. That is, although not shown, the laser printer includes a microcomputer, and includes image data memories 12R, 12G, and 12B as memories for storing image data for recording images on the photographic paper 224. . The image data memory 12R is a memory for storing R color image data, the image data memory 12G is a memory for storing G color image data, and the image data memory 12B is a memory for storing B color image data. It is.
[0042]
Each of the image data memories 12R, 12G, and 12B is connected to modulation means 14R, 14G, and 14B in charge of the laser light sources 211R, 211G, and 211B for the respective colors. The modulation means modulates the laser beam based on the image data. The modulation means 14R, 14G, and 14B may be indirect modulation using an acousto-optic element (AOM) or the like, or may be direct modulation using pulse width modulation or the like.
[0043]
Further, in order to suppress the light amount fluctuation over time and the light amount fluctuation due to the environmental temperature change and stably drive the laser light sources 211R, 211G, 211B, the light output corresponding to each laser light source 211R, 211G, 211B. Control means 10R, 10G, 10B and temperature control means 18R, 18G, 18B are provided.
[0044]
Further, the laser printer includes a light emission timing control unit 16R, and the light synchronization detection unit 228 is connected to the light emission timing control unit 16R. The light synchronization detection means 228 detects the start of scanning and outputs the detection signal to the light emission timing control means 16R. The light emission timing control means 16R is based on the detection signal from the light synchronization detection means 228. The light emission timings of the laser light sources 211R, 211G, and 211B are controlled. Note that a light emission timing control unit may be provided for each color, and the light synchronization detection unit 228 may be connected to the light emission timing control unit for each color.
[0045]
The light output control means 10R, 10G, 10B for each color are connected to light output detection means 20R, 20G, 20B and LD operating current setting means 22R, 22G, 22B corresponding to the respective colors. Each light output detection means 20R, 20G, 20B is for detecting the amount of light emitted from the corresponding laser light source 211R, 211G, 211B, and the detected value is input to the corresponding light output control means 10R, 10G, 10B. Then, each light output control means 10R, 10G, 10B outputs a control signal to the corresponding LD operation current setting means 22R, 22G, 22B, so that each LD operation current setting means 22R, 22G, 22B corresponds to a laser light source. 211R, 211G, and 211B are driven (for example, so that it may become a fixed light quantity).
[0046]
Also, LD temperature detecting means 24R, 24G, 24B and LD heating / cooling means 26R, 26G, 26B are connected to the temperature control means 18R, 18G, 18B for each color corresponding to each color. Each LD temperature detection means 18R, 18G, 18B is for detecting the temperature of the corresponding laser light source 211R, 211G, 211B, and the detected value is input to the corresponding temperature control means 18R, 18G, 18B, Each temperature control means 18R, 18G, 18B outputs a control signal to the corresponding LD heating / cooling means 26R, 26G, 26B, whereby each LD heating / cooling means 26R, 26G, 26B corresponds to the corresponding laser light source 211R, 211G, 211B. The temperature is adjusted (for example, to be a constant temperature).
[0047]
As described above, in this embodiment, the light amount adjustment and the temperature adjustment are performed for each laser light source of a different color, so that it is possible to obtain a stable laser light without variation of each laser light source. it can.
[0048]
Next, the flow during exposure control during printing in the laser printer configured as described above will be described with reference to the flowcharts of FIGS.
[0049]
The entire flow of exposure control in FIG. 3 will be described. The exposure control is performed for each of the laser light sources 211R, 211G, and 211B. In the following description, the laser light sources 211R, 211G, and 211B are simply referred to as LD.
[0050]
In step S10, the light amount is adjusted. That is, the amount of light is adjusted by controlling the drive current so that each LD continuously emits light and reaches a predetermined target amount of light. Specifically, the light amount adjustment is performed according to the flowchart of FIG.
[0051]
First, in step S100, the LD continuous emission signal is turned on and the LD operating current I _CW Starts setting. That is, the LD emits light continuously.
[0052]
In step S102, the amount of laser light emitted from the LD is detected by the light output detection means 20R, 20G, 20B, and the process proceeds to step S104.
[0053]
In step S104, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is smaller. When the determination is affirmative, the process proceeds to step S106, the LD operating current is increased by the LD operating current setting means 22R, 22G, and 22B, the process proceeds to step S108, and the determination in step S104 is denied , The process proceeds to step S108 as it is.
[0054]
In step S108, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is larger. If the determination is affirmative, the process proceeds to step S110, where the LD operating current setting means 22R, 22G, 20B decreases the LD operating current, the process proceeds to step S112, and the determination in step S108 is negative , The process proceeds to step S112 as it is.
[0055]
In step S112, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether or not. If the determination is negative, the process returns to step S102 described above, and the detected light amount P is changed to the target light amount P. _O The above process is repeated until
[0056]
If the determination in step S112 is affirmative, the process proceeds to step S114, and the target light amount P _O LD operating current I _CW Is stored, the light amount adjustment process is terminated, and the process proceeds to step S20 in FIG.
[0057]
In step S20 of FIG. 3, standby processing is performed. In the standby process, optical scanning is performed for each line for each of the laser light sources 211R, 211G, and 211B, and the start point is detected. At this time, APC control is simultaneously performed. Specifically, standby processing is performed according to the flowchart of FIG.
[0058]
First, in step S200, it is determined whether or not the synchronization of the polygon mirror 218 has been detected. The process waits until the determination is affirmed, and the process proceeds to step S202.
[0059]
In step S202, the LD light emission signal is turned on, and the LD operating current I _PS Starts setting. That is, the LD operating current I for recording an image _PS The setting of is started. At this time, first, the LD operating current I stored at the time of adjusting the light amount _CW Read out the LD operating current I _CW LD operating current I smaller by a predetermined value than _OS As a result, the LD is driven.
[0060]
Next, in step S204, the start point is detected by the optical synchronization detection means 228, and the process proceeds to step S206, where image output control is started for each line.
[0061]
Then, the process proceeds to step S208, and the amount of laser light emitted from the LD is detected by the light output detection means 20R, 20G, 20B, and the process proceeds to step S210.
[0062]
In step S210, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is smaller. If the determination is affirmative, the process proceeds to step S212, the operating current is increased by the LD operating current setting means 22R, 22G, and 22B, the process proceeds to step S214, and the determination in step S210 is denied. Proceeds directly to step S214.
[0063]
In step S214, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is larger. If the determination is affirmative, the process proceeds to step S216, the operating current is decreased by the LD operating current setting means 22R, 22G, 22B, the process proceeds to step S218, and the determination in step S214 is denied. Proceeds directly to step S218.
[0064]
In step S218, the detected light amount detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether or not. If the determination is negative, the process returns to step S208 described above, and the detected light quantity P is the target light quantity P. _O The above process is repeated until
[0065]
When the determination in step S218 is affirmed, the process proceeds to step S220, and the target light amount P _O LD operating current I _PS Is stored, the standby process is terminated, and the process proceeds to step S30 in FIG.
[0066]
FIG. 7 shows an example of control in units of one line during standby processing. In the standby process, in detail, with the photographic paper 224 not passed, as shown in FIG. 7, pulse light emission is performed in units of one line using dummy image data (for example, gray solid fixed data) and APC control is performed. I do. For the laser light source 211R, the start point is detected after the APC control. That is, since pulse emission is performed as in the case of image output, the temperature of the semiconductor laser becomes the same as that at the time of actual image recording, and the temperature of the semiconductor laser can be set to the same state as at the time of image recording. Sometimes, the light output can be stabilized and a high-quality image can be obtained. In FIG. 7, pulse light emission is performed using dummy image data. However, APC control and start point detection may be performed. In other words, the APC control and the start point detection in the standby process cause the LD to emit light for a short time, and thus can be said to be pulsed emission. In addition, only the pulse emission at the time of APC control and detection of the start point can bring the temperature of the semiconductor laser close to the same state as at the time of image recording, although the effect is less than the above. It is possible to obtain a high-quality image.
[0067]
In step S30 in FIG. 3, an image output process is performed. In other words, the laser light is modulated by the modulation means 14R, 14G, and 14B based on the image data and irradiated onto the photographic paper 224, whereby the image is recorded on the photographic paper 224. At this time, in this embodiment, APC control is performed as needed during each line scan. Specifically, image output processing is performed according to the flowchart of FIG.
[0068]
First, in step S300, the LD light emission signal is turned on, and the LD operating current I _PS The setting of is started. That is, the LD operating current I for recording an image _PS The setting of is started. At this time, first, the LD operating current I recorded at the time of standby or the previous image output is obtained. _PS And the LD operating current I _PS As a result, the LD is driven.
[0069]
Next, in step S302, image output control is started for each line, and the process proceeds to step S304 where the laser beam is modulated based on the image data and optically scanned on the recording medium.
[0070]
Then, the process proceeds to step S306, where the light amount of the laser light emitted from the LD is detected by the light output detection means 20R, 20G, 20B, and the process proceeds to step S308.
[0071]
In step S308, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is smaller. If the determination is affirmative, the process proceeds to step S310, the operating current is increased by the LD operating current setting means 22R, 22G, and 22B, the process proceeds to step S312 and the determination in step S308 is denied. Shifts directly to step S312.
[0072]
In step S312, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether it is larger. If the determination is affirmative, the process proceeds to step S314, where the operating current is decreased by the LD operating current setting means 22R, 22G, and 22B, the process proceeds to step S316, and the determination in step S312 is denied. Shifts directly to step S316.
[0073]
In step S316, the detected light amount P detected by the light output detection means 20R, 20G, 20B is a predetermined target light amount P. _O It is determined whether or not. If the determination is negative, the process returns to step S306 described above, and the detected light amount P is changed to the target light amount P. _O The above process is repeated until Note that the increase or decrease in the LD operating current in steps S310 and S314 is performed sequentially for each line so that the LD operating current I can be set to the target light amount. _PS Will be set.
[0074]
If the determination in step S316 is affirmative, the process moves to step S318, and it is determined whether or not the image data output is completed, that is, the image recording for one page is completed. If the determination is negative, the process returns to step S304 described above, and the above process is repeated until the output of the image data is completed.
[0075]
If the determination in step S318 is affirmed, the process proceeds to step S320, where the target light amount P _O LD operating current I _PS Is updated, the image output process is terminated, and the process proceeds to step S40 in FIG.
[0076]
In step 40 of FIG. 3, it is determined whether or not continuous printing is performed. This determination is made by determining whether or not continuous printing has been instructed, whether or not a printing instruction has been issued immediately following the initial print instruction, and in the case of continuous printing, the determination is affirmed and the above-described determination is made. Returning to step S30, the image output process is performed, and the process is repeated until the determination in step S40 is denied. When the determination in step S40 is denied, the series of exposure control processes is terminated.
[0077]
That is, in the present embodiment, as shown in FIG. 8, first, initialization is performed immediately after the power is turned on. Initialization immediately after power-on is performed by causing the LD to emit light continuously and the target light amount P as in the prior art. _O Gradually increase the operating current so that the target light amount P _O LD operating current I _CW Is stored, and the light amount is adjusted. The LD operating current I _CW LD operating current I smaller by a predetermined value than _OS In this way, the LD is caused to emit light in the same manner as when outputting an image while detecting the start point and adjusting the light amount (APC control) to obtain the LD operating current I that becomes the target light amount _PS Is stored.
[0078]
Then, at the time of image output of the present embodiment, that is, at the time of the print sequence shown in FIG. _PS The image is output while performing APC control using the. In other words, APC control is performed at any time during image output, and the LD operating current I _PS Is updated and stored as needed, so that an image is output with a stable light quantity. Also, during the continuous sequence (continuous printing), the LD operating current I updated and stored _PS Is used to output an image and APC control is performed as needed. Accordingly, during continuous printing, the amount of light adjustment and the printing time for standby can be shortened as compared with the conventional technique (see FIG. 10). As the number of continuous prints increases, the print time can be shortened compared to the conventional case.
[0079]
In addition, as described above, APC control is performed at any time during image output, and the LD operating current I _PS Is updated, and the LD operating current I _PS Since the image is output using the, an image can be recorded with a stable light amount, and a high-quality image can be obtained.
[0080]
It should be noted that when printing is performed after a certain amount of time has elapsed since the LD light amount is raised, the printing may be performed from the standby in step S20 in FIG. In other words, in the present embodiment, the temperature of each LD is adjusted by the LD cooling and heating means 26R, 26G, and 26B. Therefore, by adjusting the light amount during standby, variations in the light amount due to temperature changes can be suppressed. .
[0081]
Further, standby may be performed between image outputs during continuous printing. That is, when step S40 in FIG. 3 is affirmed, the process may return to step S20. As a result, the printing time is longer than in the above-described embodiment, but the amount of light is adjusted by standby, so that the image quality can be recorded stably.
[0082]
【The invention's effect】
As described above, according to the present invention, since the drive amount of the semiconductor laser at the time of standby control is stored and used at the time of image recording, an image can be recorded with a stable light amount without repeating light amount adjustment and standby control. In addition, the printing time can be shortened and a high-quality image can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an optical system of a laser printer according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a functional configuration of a laser printer according to an embodiment of the present invention.
FIG. 3 is a flowchart showing the overall flow of exposure control during printing in the laser printer according to the embodiment of the present invention.
FIG. 4 is a flowchart illustrating light amount adjustment processing.
FIG. 5 is a flowchart illustrating standby processing.
FIG. 6 is a flowchart illustrating image output processing.
FIG. 7 is a timing chart illustrating an example of control in units of one line during standby processing.
FIG. 8 is a diagram showing exposure control operating current and light output in the laser printer according to the embodiment of the present invention;
FIG. 9 is a graph showing the relationship between the drive current and the optical output for each operating environment temperature of the semiconductor laser.
FIG. 10 is a diagram showing an operation current and light output for exposure control in a conventional laser printer.
FIG. 11 is a diagram showing an exposure control operating current and optical output in another conventional laser printer.
[Explanation of symbols]
10R, 10G, 10B Light output control means
12R, 12G, 12B Image data memory
14R, 14G, 14B Modulation means
20R, 20G, 20B Optical output detection means
22R, 22G, 22B LD operating current setting means
211R, 211G, 211B Semiconductor laser

Claims (9)

A semiconductor laser that emits laser light;
Detecting means for detecting the amount of laser light emitted from the semiconductor laser;
A light amount control means for driving and controlling the semiconductor laser so that the semiconductor laser continuously emits light when the power is turned on, and the light amount detected by the detection means becomes a predetermined target light amount;
Standby control means for driving and controlling the semiconductor laser so that the target light quantity is obtained by causing the semiconductor laser to emit pulses based on the drive quantity at the target light quantity when the semiconductor laser is driven by the light quantity control means; ,
Storage means for storing a drive amount at the target light amount when the semiconductor laser is driven by the standby control means;
When recording an image, an image is recorded based on the driving amount at the target light amount stored in the storage unit, and the semiconductor laser is driven and adjusted so that the target light amount is obtained, and stored in the storage unit. Image recording means for storing and updating the driving amount at the target light amount;
An image recording apparatus comprising: The standby control unit causes the semiconductor laser to emit light with a driving amount that is a predetermined amount smaller than a driving amount at the time of the target light amount when the semiconductor laser is driven by the light amount control unit so as to obtain the target light amount. The image recording apparatus according to claim 1, wherein the semiconductor laser is driven and controlled. 3. The image recording apparatus according to claim 1, wherein the standby control unit causes the semiconductor laser to emit light so as to emit light during image recording when the pulsed light is emitted. The image recording unit records an image based on the driving amount at the target light amount stored in the storage unit and continuously drives the semiconductor laser to obtain the target light amount when recording images continuously. 4. The image recording apparatus according to claim 1, wherein the image recording apparatus adjusts and updates the drive amount at the target light amount stored in the storage unit. 5. The image recording apparatus according to claim 1, further comprising a heating / cooling unit that adjusts a temperature by heating or cooling the semiconductor laser. A light amount control step for continuously driving the semiconductor laser at power-on, detecting laser light emitted from the semiconductor laser, and driving and controlling the semiconductor laser so that the detected light amount becomes a predetermined target light amount;
A standby step for driving and controlling the semiconductor laser so that the detected light amount becomes the target light amount by pulse-emitting the semiconductor laser based on the drive amount of the semiconductor laser at the target light amount in the light amount control step;
A storage step for storing a driving amount of the semiconductor laser at the target light amount in the standby step;
When recording an image, based on the drive amount at the target light amount stored in the storage step, the image is recorded, and the semiconductor laser is driven and adjusted so that the detected light amount becomes the target light amount. An image recording step of storing and updating the drive amount at the target light amount stored in
An image recording method comprising: In the standby step, the semiconductor laser is pulse-emitted with a driving amount smaller than a driving amount at the target light amount at the time of driving the semiconductor laser in the light amount control step, so that the target light amount is obtained. 7. The image recording method according to claim 6, wherein the semiconductor laser is driven and controlled. 8. The image recording method according to claim 6, wherein, in the standby step, the semiconductor laser is caused to emit light so as to emit a pulse at the time of image recording when the semiconductor laser emits the pulse. In the image recording step, when continuously recording images, an image is recorded based on the drive amount at the target light amount stored in the storage step, and the semiconductor device is configured so that the detected light amount becomes the target light amount 9. The image recording method according to claim 6, wherein the laser is driven and adjusted, and the driving amount at the target light amount stored in the storing step is stored and updated.

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