JP2009044048A - Correction method, light source apparatus, program, recording medium, optical scanning apparatus, image forming device, testing device, and test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To individually correct, with high accuracy, a drive current of each light emission part of laser array which has a plurality of light emission parts. <P>SOLUTION: After turning on all light emission parts in a plurality of light emission parts and determining a total optical output Pt, one light emission part out of a plurality of light emission parts is turned off (step S427) to determine an optical output Ptd as a total output of all light emission parts except one light emission part (step S429). The optical output of one light emission part under the environment where almost all lights in a two dimensional array are turned on can be determined this way. Then, based on the difference between the optical output Pt and the optical output Ptd and the slope efficiency of one light emission part, a compensation value ΔIon of drive current in one light emission part is obtained (Step S433). With the compensation value ΔIon, the drive current in one light emission part can be corrected in accordance with the condition of actual operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a correction method, a light source device, a program, a recording medium, an optical scanning device, an image forming device, a test device, and a test method, and more specifically, corrects a drive current value of a laser array having a plurality of light emitting units. Correction method, light source device capable of outputting a plurality of lights, a program used for a computer for controlling a light source device including a laser array having a plurality of light emitting units, a computer-readable recording medium on which the program is recorded, and scanned by light The present invention relates to an optical scanning apparatus that scans a surface, an image forming apparatus including the optical scanning apparatus, a laser array test apparatus and a test method having a plurality of light emitting units.

  In recent years, image forming apparatuses such as laser printers and digital copying machines have been desired to improve printing speed (high speed) and write density (high image quality). As a method for achieving these requirements, a method of scanning a surface to be scanned with a plurality of light beams using a multi-beam light source capable of emitting a plurality of light beams has been considered.

  In a laser array having a plurality of light emitting units, the interval between the light emitting units is close to several tens of μm, and it is difficult to monitor the light output of each light emitting unit alone. Therefore, it is difficult to perform so-called APC (Automatic Power Control) driving in which a feedback operation is performed so as to obtain a constant light output. Therefore, even if the temperature of the active layer of the light emitting part increases and the light output decreases due to thermal interference between adjacent light emitting parts, it is difficult to individually correct the light output.

  For example, in Patent Document 1, a voltage is selectively applied to a driving transistor provided for each of a plurality of semiconductor laser elements integrated in an array, and a plurality of semiconductor laser elements are applied with an operating current corresponding to the applied voltage. In the selectively driven semiconductor laser array driving circuit, the input terminal of the applied voltage of the driving transistor of the semiconductor laser element and the base of the driving transistor of the semiconductor laser element integrated adjacent to the semiconductor laser element are: A semiconductor laser array drive circuit is disclosed in which a resistor and one end thereof are connected via a grounded capacitor. This semiconductor laser array drive circuit adds a temperature-compensated current corresponding to the light output fluctuation of the adjacent semiconductor laser element due to the heat generated by the semiconductor laser element to the operating current of the adjacent semiconductor laser element by a combination of a resistor and a capacitor. The light output fluctuation due to thermal interference between the semiconductor laser elements is corrected with a simple circuit configuration.

JP-A-5-327084

  However, in the semiconductor laser array driving circuit disclosed in Patent Document 1, it is necessary to measure the optical output fluctuation due to thermal interference in advance and set a circuit constant for correcting the optical output fluctuation. In this case, there is a disadvantage that the circuit constant must be changed. Further, when the semiconductor laser array is a two-dimensional array, there is a disadvantage that the circuit becomes complicated.

  The present invention has been made under such circumstances, and its first object is to provide a correction method capable of individually and accurately correcting the drive current value of each light emitting unit of a laser array having a plurality of light emitting units. It is to provide.

  A second object of the present invention is to provide a light source device that can stably output a plurality of lights.

  A third object of the present invention is to provide a program that can be executed by a computer for controlling a light source device and that can stably output a plurality of lights, and a recording medium on which the program is recorded. is there.

  A fourth object of the present invention is to provide an optical scanning device capable of performing stable optical scanning.

  A fifth object of the present invention is to provide an image forming apparatus capable of forming a high quality image.

  A sixth object of the present invention is to provide a test apparatus and a test method capable of accurately measuring the characteristics of each light emitting part of a laser array having a plurality of light emitting parts.

  According to a first aspect of the present invention, there is provided a correction method for correcting a drive current value of a laser array having a plurality of light emitting units, the step of obtaining a slope efficiency of at least one light emitting unit among the plurality of light emitting units. And turning on all of the plurality of light emitting units to obtain a total light output Pt; and turning off the at least one light emitting unit and total light of all remaining light emitting units excluding the at least one light emitting unit. A correction method comprising: obtaining an output Ptd; obtaining correction information of a drive current value of the at least one light emitting unit based on a difference between the light output Pt and the light output Ptd and the slope efficiency. It is.

  According to this, when all of the plurality of light emitting units are turned on and the total light output Pt is obtained, at least one light emitting unit of the plurality of light emitting units is turned off, and all the remaining except for the at least one light emitting unit. The total light output Ptd of the light emitting units is obtained. Then, based on the difference between the light output Pt and the light output Ptd and the slope efficiency, correction information on the drive current value of at least one light emitting unit is acquired. In this case, the correction information is acquired so that the drive current value matches the actual usage situation. Therefore, it is possible to individually correct the drive current value of each light emitting unit of the laser array having a plurality of light emitting units with high accuracy.

  According to a second aspect of the present invention, there is provided a laser array having a plurality of light emitting units; a photodetector for receiving light emitted from the laser array; The light output Pt is obtained via the photodetector, at least one of the plurality of light emitting units is turned off, and the total light output Ptd of all the remaining light emitting units excluding the at least one light emitting unit is calculated as the light output Ptd. The correction information of the drive current value of the at least one light emitting unit is obtained based on the difference between the light output Pt and the light output Ptd and the slope efficiency of the at least one light emitting unit. And a correction device.

  According to this, after all of the plurality of light emitting units are turned on by the correction device and the total light output Pt is obtained through the photodetector, at least one of the plurality of light emitting units is turned off. The total light output Ptd of all the remaining light emitting units except at least one light emitting unit is obtained via the photodetector. Then, correction information for the drive current value of at least one light emitting unit is acquired by the correction device based on the difference between the light output Pt and the light output Ptd and the slope efficiency of at least one light emitting unit. In this case, the correction information is acquired so that the drive current value matches the actual usage situation. Therefore, it becomes possible to output a plurality of lights stably.

  According to a third aspect of the present invention, there is provided a program for use in a computer for controlling a light source device including a laser array having a plurality of light emitting units, wherein the slope efficiency of at least one light emitting unit among the plurality of light emitting units. A procedure for turning on all of the plurality of light emitting portions to obtain a total light output Pt; and a step of turning off the at least one light emitting portion and removing all of the remaining light emitting portions excluding the at least one light emitting portion. A procedure for obtaining a total light output Ptd; and a procedure for obtaining correction information for the drive current value of the at least one light emitting unit based on the difference between the light output Pt and the light output Ptd and the slope efficiency. A program to be executed by the control computer.

  According to this, when the program of the present invention is loaded into a predetermined memory and the head address thereof is set in the program counter, the control computer of the light source device causes the slope of at least one light emitting unit among the plurality of light emitting units. After obtaining the efficiency, when all of the plurality of light emitting units are turned on to obtain the total light output Pt, at least one light emitting unit is turned off and the total of all remaining light emitting units excluding the at least one light emitting unit is calculated. The optical output Ptd is obtained. Then, based on the difference between the light output Pt and the light output Ptd and the slope efficiency, correction information on the drive current value of at least one light emitting unit is acquired. In this case, the correction information is acquired so that the drive current value matches the actual usage situation. Therefore, the light source device can stably output a plurality of lights.

  From the fourth viewpoint, the present invention is a computer-readable recording medium on which the program of the present invention is recorded.

  According to this, since the program of the present invention is recorded, it is possible to stably output a plurality of lights by causing the computer to execute the program.

  According to a fifth aspect of the present invention, there is provided an optical scanning device that scans a surface to be scanned with light, the light source device of the present invention; a deflector that deflects light output from the light source device; And a scanning optical system for condensing the light deflected by the instrument on the surface to be scanned.

  According to this, since the light source device of the present invention is provided, as a result, stable optical scanning can be performed.

  According to a sixth aspect of the present invention, there is provided an image comprising: at least one image carrier; and at least one optical scanning device according to the invention that scans the at least one image carrier with light containing image information. Forming device.

  According to this, since at least one optical scanning device of the present invention is provided, as a result, a high-quality image can be formed.

  According to a seventh aspect of the present invention, there is provided a test apparatus for testing a laser array having a plurality of light emitting units, wherein a socket in which a laser array to be tested is set; and light emitted from the laser array is received. A light output Pt obtained from the light detector when all of the plurality of light emitting units are turned on, and a light output obtained from the light detector when only one of the plurality of light emitting units is sequentially turned off. A measuring device for measuring a light output Ptd to be obtained and obtaining a driving current value necessary for obtaining a predetermined light output based on a difference between the light output Pt and the light output Ptd and a slope efficiency for each light emitting unit; A test apparatus.

  According to this, when all of the plurality of light emitting units are turned on by the measuring device and the total light output Pt is obtained via the photodetector, the light is emitted when only one of the plurality of light emitting units is sequentially turned off. The light output Ptd obtained from the detector is measured. Then, a driving current value necessary for obtaining a predetermined light output is obtained for each light emitting unit by the measuring device based on the difference between the light output Pt and the light output Ptd and the slope efficiency. In this case, a drive current value in accordance with the actual use situation is obtained. Therefore, it is possible to accurately measure the characteristics of each light emitting part of the laser array having a plurality of light emitting parts.

  According to an eighth aspect of the present invention, there is provided a test method for testing a laser array having a plurality of light emitting units, the step of obtaining a slope efficiency of at least one light emitting unit among the plurality of light emitting units; Turning on all of the light emitting parts to obtain the total light output Pt; turning off the light emitting part to be tested and obtaining the total light output Ptd of all the remaining light emitting parts excluding the at least one light emitting part. Obtaining a driving current value necessary for obtaining a predetermined light output for the at least one light emitting unit based on a difference between the light output Pt and the light output Ptd and the slope efficiency; It is a correction method including.

  According to this, the slope efficiency of at least one light emitting unit among the plurality of light emitting units is required. Then, after all of the plurality of light emitting units are turned on and the total light output Pt is obtained, at least one light emitting unit is turned off, and the total light output of all the remaining light emitting units excluding the at least one light emitting unit. Ptd is determined. Then, based on the difference between the light output Pt and the light output Ptd and the slope efficiency, a driving current value necessary for obtaining a predetermined light output is obtained for at least one light emitting unit. In this case, a drive current value in accordance with the actual use situation is obtained. Therefore, it is possible to accurately measure the characteristics of each light emitting part of the laser array having a plurality of light emitting parts.

<Image forming apparatus>
Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a printer 1000 as an image forming apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the printer 1000 includes an optical scanning device 1010, a photosensitive drum 1030, a charging charger 1031, a developing roller 1032, a transfer charger 1033, a static elimination unit 1034, a cleaning blade 1035, a toner cartridge 1036, a paper feeding roller. 1037, a paper feed tray 1038, a registration roller pair 1039, a fixing roller 1041, a paper discharge roller 1042, a paper discharge tray 1043, and the like.

  A photosensitive layer is formed on the surface of the photosensitive drum 1030. That is, the surface of the photoconductor drum 1030 is a scanned surface. Here, the photosensitive drum 1030 rotates in the direction of the arrow in FIG.

  The charging charger 1031, the developing roller 1032, the transfer charger 1033, the charge removal unit 1034, and the cleaning blade 1035 are each arranged in the vicinity of the surface of the photosensitive drum 1030. Then, with respect to the rotation direction of the photosensitive drum 1030, the charging charger 1031 → the developing roller 1032 → the transfer charger 1033 → the charge eliminating unit 1034 → the cleaning blade 1035 are arranged in this order.

  The charging charger 1031 uniformly charges the surface of the photosensitive drum 1030.

  The optical scanning device 1010 irradiates the surface of the photosensitive drum 1030 charged by the charging charger 1031 with a light beam modulated based on image information from a host device (for example, a personal computer). As a result, a latent image corresponding to the image information is formed on the surface of the photosensitive drum 1030 on the surface of the photosensitive drum 1030. The latent image formed here moves in the direction of the developing roller 1032 as the photosensitive drum 1030 rotates. The configuration of the optical scanning device 1010 will be described later.

  The toner cartridge 1036 stores toner, and the toner is supplied to the developing roller 1032.

  The developing roller 1032 causes the toner supplied from the toner cartridge 1036 to adhere to the latent image formed on the surface of the photosensitive drum 1030 to visualize the image information. Here, the latent image to which the toner is attached (hereinafter also referred to as “toner image” for the sake of convenience) moves in the direction of the transfer charger 1033 as the photosensitive drum 1030 rotates.

  Recording paper 1040 is stored in the paper feed tray 1038. A paper feed roller 1037 is disposed in the vicinity of the paper feed tray 1038, and the paper feed roller 1037 takes out the recording paper 1040 one by one from the paper feed tray 1038 and conveys it to the registration roller pair 1039. The registration roller pair 1039 temporarily holds the recording paper 1040 taken out by the paper supply roller 1037, and in the gap between the photosensitive drum 1030 and the transfer charger 1033 according to the rotation of the photosensitive drum 1030. Send it out.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 1033 in order to electrically attract the toner on the surface of the photosensitive drum 1030 to the recording paper 1040. With this voltage, the toner image on the surface of the photosensitive drum 1030 is transferred to the recording paper 1040. The recording sheet 1040 transferred here is sent to the fixing roller 1041.

  In the fixing roller 1041, heat and pressure are applied to the recording paper 1040, whereby the toner is fixed on the recording paper 1040. The recording paper 1040 fixed here is sent to the paper discharge tray 1043 via the paper discharge roller 1042 and is sequentially stacked on the paper discharge tray 1043.

  The neutralization unit 1034 neutralizes the surface of the photosensitive drum 1030.

  The cleaning blade 1035 removes toner (residual toner) remaining on the surface of the photosensitive drum 1030. The removed residual toner is used again. The surface of the photosensitive drum 1030 from which the residual toner has been removed returns to the position of the charging charger 1031 again.

<Optical scanning device>
Next, the configuration of the optical scanning device 1010 will be described.

  As shown in FIG. 2 as an example, the optical scanning device 1010 includes a light source 14, a coupling lens 15, an aperture plate 16, a cylindrical lens 17, a reflection mirror 18, a polygon mirror 13, a deflector side scanning lens 11a, an image plane. A side scanning lens 11b, a half mirror 23, an imaging lens 24, a light receiver 25, a scanning control device (not shown), and the like are provided. In this specification, the longitudinal direction of the photosensitive drum 1030 will be described as a Y-axis direction, and two directions orthogonal to each other in a plane perpendicular to the Y-axis direction will be described as a Z-axis direction and an X-axis direction.

  The scanning control device generates a writing signal based on image information from the host device.

  As shown in FIG. 3 as an example, the light source 14 includes a two-dimensional array 14A, a drive circuit 14B, and a drive current correction circuit 14C.

  In the two-dimensional array 14A, as shown in FIG. 4 as an example, 40 light emitting units are two-dimensionally arranged on one substrate.

  The two-dimensional array 14A is also referred to as a direction corresponding to the sub-scanning direction (hereinafter also referred to as “S direction” for convenience) from a direction corresponding to the main scanning direction (hereinafter also referred to as “M direction” for convenience). The same as the Z-axis direction), and the four light emitting units arranged at equal intervals (for example, 40 μm) along a direction (hereinafter referred to as “T direction” for convenience) that forms an inclination angle α. There are 10 columns. And these 10 light emission part row | line | columns are arrange | positioned at equal intervals (for example, 40 micrometers) in the direction orthogonal to T direction. That is, 40 light emitting units are arranged in a matrix. Here, for the sake of convenience, the first light emitting unit row, the second light emitting unit row,..., The tenth light emitting unit row are referred to from the top to the bottom in FIG. In the present specification, the “light emitting portion interval” refers to the distance between the centers of two light emitting portions.

  Further, in order to specify each light emitting unit, for convenience, the four light emitting units constituting the first light emitting unit row are configured from v1 to v4 and the second light emitting unit row from the upper left to the lower right in FIG. .., And the four light emitting units constituting the tenth light emitting unit row are numbered v37 to v40.

Each light emitting unit is a vertical cavity surface emitting laser (VCSEL) of 780 nm band, and emits light in the + X direction. Here, as an example, the area of the opening due to oxidation constriction in each light emitting portion is 20 μm ² .

  As shown in FIG. 5 as an example, the drive current correction circuit 14C includes a CPU 141, a flash memory 142, and a RAM 143, and generates a signal for correcting the drive current value (hereinafter referred to as “correction signal”).

  The flash memory 142 stores various programs including a program according to an embodiment of the present invention described by a code readable by the CPU 141.

  The RAM 143 is a working memory.

  The CPU 141 performs predetermined processing including processing for correcting the driving current value (hereinafter referred to as “driving current value correction processing”) in accordance with the program stored in the flash memory 142. The drive current value correction process performed by the CPU 141 will be described later.

  The drive circuit 14B determines the drive current value of each light emitting section of the two-dimensional array 14A based on the write signal from the scanning control device and the correction signal from the drive current correction circuit 14C, and supplies the drive current value to the two-dimensional array 14A.

  Returning to FIG. 2, the coupling lens 15 is disposed on the + X side of the light source 14, and makes the light beam emitted from the light source 14 substantially parallel light.

  The aperture plate 16 is disposed on the + X side of the coupling lens 15 and has an aperture that defines at least the beam diameter of the light passing through the coupling lens 15 in the Z-axis direction.

  The half mirror 23 is disposed on the + X side of the aperture plate 16 and reflects a part of the light beam that has passed through the aperture of the aperture plate 16.

  The cylindrical lens 17 is disposed on the + X side of the half mirror 23, and forms an image of the light that has passed through the half mirror 23 in the vicinity of the deflection reflection surface of the polygon mirror 13 with respect to the Z-axis direction via the reflection mirror 18.

  By the way, the optical system arranged on the optical path between the light source 14 and the polygon mirror 13 is also called a pre-deflector optical system. In the present embodiment, the pre-deflector optical system includes a coupling lens 15, an aperture plate 16, a half mirror 23, a cylindrical lens 17, and a reflection mirror 18.

  A soundproof glass 21 is disposed between the reflection mirror 18 and the polygon mirror 13 and between the polygon mirror 13 and the deflector side scanning lens 11a.

  The polygon mirror 13 has a four-sided mirror, and each mirror serves as a deflection reflection surface. The polygon mirror 13 rotates at a constant speed around a rotation axis parallel to the Z-axis direction, and deflects light incident through the reflection mirror 18.

  The deflector-side scanning lens 11 a is disposed on the optical path of the light beam deflected by the polygon mirror 13.

  The image plane side scanning lens 11b is disposed on the optical path of the light beam via the deflector side scanning lens 11a.

  The optical system arranged on the optical path between the polygon mirror 13 and the photosensitive drum 1030 is also called a scanning optical system. In the present embodiment, the scanning optical system includes a deflector side scanning lens 11a and an image plane side scanning lens 11b.

  The light deflected by the polygon mirror 13 is imaged by the scanning optical system and condensed as a light spot on the surface of the photosensitive drum 1030. This light spot moves in the Y-axis direction as the polygon mirror 13 rotates. The moving direction of the light spot at this time is the main scanning direction.

  The imaging lens 24 condenses the light beam reflected by the half mirror 23. A light receiver 25 is disposed in the vicinity of the light collection position, and a signal (photoelectric conversion signal) corresponding to the amount of received light is output to the drive current correction circuit 14C. The light receiver 25 has a plurality of light receiving elements or light receiving regions corresponding to the plurality of light emitting portions of the two-dimensional array 14A.

  A dustproof glass 22 is disposed between the image surface side scanning lens 11b and the photosensitive drum 1030.

<< Drive current value correction process >>
Next, drive current value correction processing performed by the CPU 141 will be described with reference to FIGS. 6 (A) and 6 (B). The flowcharts of FIGS. 6A and 6B correspond to a series of processing algorithms executed by the CPU 141.

  For example, when the CPU 141 receives a drive current value correction request from the scanning control device, the start address of the program corresponding to the flowcharts of FIGS. 6A and 6B is set in the program counter of the CPU 141, and the drive current value The correction process starts.

  In the first step S401, the initial value 1 is set to the counter n, and 40 is set to the number Num of light emitting units.

  In the next step S403, the light emitting unit vn which is the nth light emitting unit is set as the designated light emitting unit.

  In the next step S405, the designated light emitting unit is driven with a plurality of drive current values via the drive circuit 14B, and the current-light output characteristics of the designated light emitting unit are obtained from the output signal of the light receiver 25 at each drive current value. To do.

  In the next step S407, the slope efficiency η is calculated from the current-light output characteristics of the designated light emitting unit. For example, a value of η = 0.8 W / A is calculated for the light emitting unit v1.

  In the next step S409, a drive current value Ion corresponding to the planned light output Po (for example, 1.2 mW) is calculated. For example, a value of Ion = 3 mA is calculated for the light emitting unit v1.

  In the next step S411, it is determined whether or not the value of the counter n is smaller than the number of light emitting units Num. If the value of the counter n is smaller than the number of light emitting units Num, the determination here is affirmed and the process proceeds to step S413.

  In step S413, 1 is added to the value of the counter n, and the process returns to step S403.

  Thereafter, the processes in steps S403 to S413 are repeated until the determination in step S411 is denied.

  When the value of the counter n becomes equal to the number of light emitting units Num, the determination in step S411 is denied and the process proceeds to step S415.

  In step S415, all the light emitting units are driven (lighted) at the respective drive current values Ion via the drive circuit 14B.

  In the next step S417, when the light output is stabilized, the light output Pt at this time is obtained from the output signal of the light receiver 25. For example, a value of Pt = 36 mW is obtained.

  In the next step S421, an initial value 1 is set to the counter n.

  In the next step S423, the light emitting unit vn is set as the target light emitting unit.

  In the next step S425, the drive current value of the target light emitting unit is gradually decreased via the drive circuit 14B, and the current-light output characteristic of the target light emitting unit is obtained from the output signal of the light receiver 25 at each drive current value. To do.

  In the next step S427, the target light emitting unit is turned off via the drive circuit 14B.

  In the next step S429, the optical output Ptd at this time is acquired from the output signal of the light receiver 25. For example, when the light emitting unit v1 is turned off, a value of Ptd = 35 mW is obtained.

  In the next step S431, the slope efficiency η of the target light emitting unit is corrected based on the current-light output characteristics of the target light emitting unit. For example, the light emitting unit v1 is corrected to η = 0.67 W / A.

  In the next step S433, the correction amount ΔIon of the drive current value Ion of the target light emitting unit is calculated using the following equation (1). For example, if Po = 1.2 mW, Pt = 36 mW, Ptd = 35 mW, and η = 0.67 W / A for the light emitting unit v1, ΔIon = 0.30 mW.

  ΔIon = (Po− (Pt−Ptd)) / η (1)

  In the next step S435, the corrected drive current value Ioc of the target light emitting unit is calculated using the following equation (2). For example, if Ion = 3 mA and ΔIon = 0.30 mW for the light emitting unit v1, Ioc = 3.30 mW.

  Ioc = Ion + ΔIon (2)

  In the next step S437, it is determined whether or not the value of the counter n is smaller than the number of light emitting units Num. If the value of the counter n is smaller than the number of light emitting units Num, the determination here is affirmed and the process proceeds to step S439.

  In step S439, 1 is added to the value of the counter n, and the process returns to step S423.

  Thereafter, the processes in steps S423 to S439 are repeated until the determination in step S437 is denied.

  When the value of the counter n becomes equal to the number of light emitting units Num, the determination in step S437 is denied, and the process proceeds to step S441.

  In step S441, all the light emitting units are driven (lighted) with the respective drive current values Ioc via the drive circuit 14B.

  In the next step S443, when the light output is stabilized, the light output Pot at this time is acquired from the output signal of the light receiver 25.

  In the next step S445, the optical output difference ΔP is calculated using the following equation (3). For example, if Po = 1.2 mW and Pot = 44 mW, ΔP = 4 mW.

  ΔP = | Po × Num−Pot | (3)

  In the next step S447, it is determined whether or not ΔP is smaller than a preset allowable value ΔPo. If ΔP is not smaller than the allowable value ΔPo, the determination here is denied and the processing returns to step S421. On the other hand, if ΔP is smaller than the allowable value ΔPo, the determination here is affirmed and the drive current value correction process is terminated. For example, if the allowable value per light emitting unit is ± 0.125 mW, ΔPo = 5 mW.

  Thereby, the drive current value of each light emitting part of the two-dimensional array 14A is individually corrected with high accuracy.

  As an example, FIG. 7 shows a timing chart of light output in the drive current value correction process.

(1) Time t1 to t2
Here, the processes of steps S401 to S413 are performed.

(2) Time t3
Here, the process of step S415 is performed.

(3) Time t4
Here, the process of step S417 is performed.

(4) Time t5 to t6
Here, the processes of steps S421 to S439 are performed.

(5) Time t7
Here, the process of step S441 is performed.

(6) Time t8
Here, the process of step S443 is performed.

  When an image is formed, each light emitting unit of the two-dimensional array 14A is driven with the corrected drive current value, and optical scanning is performed.

  As is clear from the above description, in the optical scanning device 1010 according to the present embodiment, the light source 14 and the light receiver 25 constitute a light source device. The two-dimensional array 14A constitutes the laser array of the light source device, the light receiver 25 constitutes the photodetector of the light source device, and the drive current correction circuit 14C constitutes the light source device correction device.

  It should be noted that at least a part of the processing according to the program by the CPU 141 may be configured by hardware, or all may be configured by hardware.

  In the present embodiment, the program according to the present invention is executed by the programs corresponding to FIGS. 6A and 6B among the programs recorded in the flash memory 142 as the recording medium. .

  In the present embodiment, the correction method according to the present invention is implemented in the drive current value correction process.

  As described above, according to the optical scanning device 1010 according to the present embodiment, the light source 14, the light receiver 25, the polygon mirror 13 that deflects the light output from the light source 14, and the light deflected by the polygon mirror 13. And a scanning optical system that collects the light on the surface of the photosensitive drum 1030.

  Then, the drive current correction circuit 14C of the light source 14 turns on all of the plurality of light emitting units and obtains the total light output Pt, and then turns off the light emitting unit to be corrected among the plurality of light emitting units. The total light output Ptd of a plurality of light emitting parts excluding the light emitting parts is obtained. Accordingly, it is possible to measure the light output of the light emitting unit to be corrected when the two-dimensional array 14A is in an environment (state) extremely close to full lighting. Then, the drive current correction circuit 14C acquires the correction amount ΔIon (correction information) of the drive current value of the light emitting unit to be corrected based on the difference between the light output Pt and the light output Ptd and the slope efficiency of the light emitting unit to be corrected. To do. Therefore, with this correction amount ΔIon, the drive current value of the light emitting unit to be corrected can be corrected to the drive current value in accordance with the actual use situation. Therefore, it is possible to individually correct the drive current value of each light emitting unit of the laser array having a plurality of light emitting units with high accuracy.

  Thereby, it is possible to stably output a plurality of lights having a substantially uniform light output from the light source 14. As a result, the optical scanning device 1010 can perform stable optical scanning.

  That is, it is possible to correct the output distribution reflecting the temperature distribution in the two-dimensional array in the fully lit state, which has been impossible in the past, and to drive all the light emitting units with a substantially constant output.

  In addition, the printer 1000 according to the present embodiment includes the optical scanning device 1010 that can perform stable optical scanning, and as a result, a high-quality image can be formed.

  In the above embodiment, the case where the slope efficiency η is corrected in the drive current value correction process has been described. However, the present invention is not limited to this, and the slope efficiency η may not be corrected as shown in FIG. In this case, step S425 and step S431 are not necessary. As a result, the time required for the drive current value correction process can be shortened.

  In this case, the slope efficiency η used in step S433 is the slope efficiency η before correction (the slope efficiency η calculated in step S407). Therefore, for example, if Po = 1.2 mW, Pt = 36 mW, Ptd = 35 mW, and η = 0.8 W / A, ΔIon = 0.25 mW.

  FIG. 9 shows a timing chart of the light output in this case.

  In the above embodiment, the case where one light emitting unit is set as a target light emitting unit at a time in the drive current value correction processing is described. However, the present invention is not limited thereto, and a plurality of light emitting units may be set as target light emitting units at a time. . As an example, FIG. 10 shows a part of a flowchart in a case where two light emitting units are set as target light emitting units at a time. As a result, the time required for the drive current value correction process can be shortened.

  In this case, the process of step S423 ′ is performed instead of the process of step S423, and the process of step S433 ′ is performed instead of the process of step S433. Then, the process of step S436 is inserted between step S435 and step S437.

  In step S423 ′, the light emitting unit vn and the light emitting unit vn + 1 are set as target light emitting units.

  In the next step S425, the drive current value of the target light emitting unit (light emitting unit vn and light emitting unit vn + 1) is gradually decreased similarly through the drive circuit 14B, and the output signal of the light receiver 25 at each drive current value is determined. The current-light output characteristics of the target light emitting units (light emitting unit vn and light emitting unit vn + 1) are acquired.

  In the next step S427, the light emitting unit vn and the light emitting unit vn + 1 are turned off.

  In the next step S429, the optical output Ptd at this time is acquired from the output signal of the light receiver 25. For example, a value of Ptd = 34.2 mW is obtained.

  In the next step S431, the slope efficiency η of the target light emitting unit (light emitting unit vn and light emitting unit vn + 1) is corrected based on the current-light output characteristics of the target light emitting unit (light emitting unit vn and light emitting unit vn + 1). For example, it is corrected to η = 0.67 W / A.

  In step S433 ′, the correction amount ΔIon of the drive current value Ion of each target light emitting unit is calculated using the following equation (4). For example, if Po = 1.2 mW, Pt = 36 mW, Ptd = 34.2 mW, and η = 0.67 W / A, ΔIon = 0.45 mW.

  ΔIon = (Po− (Pt−Ptd) / 2) / η (4)

  In step S435, the corrected drive current value Ioc of each target light emitting unit is calculated using the above equation (2). For example, if Ion = 3 mA and ΔIon = 0.45 mW, then Ioc = 3.45 mW.

  In step S436, 1 is added to the value of the counter n.

  Also in this case, it is not necessary to correct the slope efficiency η as shown in the flowchart of FIG. In this case, step S425 and step S431 are not necessary. As a result, the time required for the drive current value correction process can be further shortened.

  In this case, the slope efficiency η used in step S433 is the slope efficiency η before correction (the slope efficiency η calculated in step S407). Therefore, for example, if Po = 1.2 mW, Pt = 36 mW, Ptd = 34.2 mW, and η = 0.8 W / A, ΔIon = 0.375 mW.

  In the above embodiment, the program according to the present invention is recorded in the flash memory 142, but is recorded in another recording medium (CD, magneto-optical disk, DVD, memory card, USB memory, flexible disk, etc.). May be. In this case, the program according to the present invention is loaded into the flash memory 142 via the playback device (or dedicated interface) corresponding to each recording medium. Further, the program according to the present invention may be transferred to the flash memory 142 via a network (LAN, intranet, Internet, etc.). In short, the program according to the present invention may be loaded into the flash memory 142.

  Moreover, although the said embodiment demonstrated the case where the light source 14 had 40 light emission parts, it is not limited to this. In short, the light source 14 may have a plurality of light emitting units. A plurality of light emitting units may be arranged one-dimensionally.

  In the above embodiment, the printer 1000 is described as the image forming apparatus. However, the present invention is not limited to this. In short, an image forming apparatus including the optical scanning device 1010 can form a high-quality image as a result.

  For example, an image forming apparatus that includes the optical scanning device 1010 and that directly irradiates laser light onto a medium (for example, paper) that develops color with laser light may be used.

  Further, an image forming apparatus using a silver salt film as the image carrier may be used. In this case, a latent image is formed on the silver salt film by optical scanning, and this latent image can be visualized by a process equivalent to a developing process in a normal silver salt photographic process. Then, it can be transferred to photographic paper by a process equivalent to a printing process in a normal silver salt photographic process. Such an image forming apparatus can be implemented as an optical plate making apparatus or an optical drawing apparatus that draws a CT scan image or the like.

  Further, even an image forming apparatus that forms a multicolor image can form a high-quality image by using an optical scanning device corresponding to the color image.

  For example, as shown in FIG. 12, a tandem color machine 1500 corresponding to a color image and including a plurality of photosensitive drums may be used. The tandem color machine 1500 includes a black (K) photosensitive drum K1, a charger K2, a developing unit K4, a cleaning unit K5, a transfer charging unit K6, a cyan (C) photosensitive drum C1, a charging unit. A developing unit C2, a developing unit C4, a cleaning unit C5, a transfer charging unit C6, a magenta (M) photosensitive drum M1, a charging unit M2, a developing unit M4, a cleaning unit M5, and a transfer charging unit M6; It includes a yellow (Y) photosensitive drum Y1, a charger Y2, a developing device Y4, a cleaning unit Y5, a transfer charging unit Y6, an optical scanning device 1010A, a transfer belt T80, a fixing unit T30, and the like. .

  In this case, the optical scanning device 1010A includes a light source device for black, a light source device for cyan, a light source device for magenta, and a light source device for yellow. Each light source device is a light source device equivalent to a light source device including the light source 14 and the light receiver 25. The light from the light source device for black is irradiated to the photosensitive drum K1 via the scanning optical system for black, and the light from the light source device for cyan is irradiated to the photosensitive drum C1 via the scanning optical system for cyan. The light from the light source device for magenta is irradiated to the photosensitive drum M1 through the scanning optical system for magenta, and the light from the light source device for yellow passes through the scanning optical system for yellow. The drum Y1 is irradiated.

  Each photosensitive drum rotates in the direction of the arrow in FIG. 12, and a charger, a developer, a transfer charging unit, and a cleaning unit are arranged in the order of rotation. Each charger uniformly charges the surface of the corresponding photosensitive drum. The surface of the photosensitive drum charged by the charger is irradiated with light by the optical scanning device 1010A, and an electrostatic latent image is formed on the photosensitive drum. Then, a toner image is formed on the surface of the photosensitive drum by the corresponding developing device. Further, the toner images of the respective colors are transferred onto the recording paper by the corresponding transfer charging means, and finally the image is fixed on the recording paper by the fixing means T30.

  In this tandem color machine 1500, instead of the optical scanning device 1010A, a black optical scanning device, a cyan optical scanning device, a magenta optical scanning device, and a yellow optical scanning device may be used. In short, the optical scanning device only needs to have a light source device equivalent to a light source device including the light source 14 and the light receiver 25.

<Test equipment>
Next, a test apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 13 shows a schematic configuration of a continuous operation test apparatus 2000 as a test apparatus according to an embodiment of the present invention.

  The continuous operation test device 2000 includes a two-dimensional array socket 2010, a drive circuit 2020, a light receiver 2030, a control device 2040, an input device 2050, a display device 2060, and the like.

  In the two-dimensional array socket 2010, a two-dimensional array equivalent to the two-dimensional array 14A can be set. A two-dimensional array set in the two-dimensional array socket 2010 is a test object of a continuous operation test.

  The drive circuit 2020 supplies a drive current to the two-dimensional array set in the two-dimensional array socket 2010 in accordance with an instruction from the control device 2040.

  The input device 2050 includes, for example, at least one input medium (not shown) of a keyboard, a mouse, a tablet, a light pen, a touch panel, and the like, and notifies the control device 2040 of various information input by the user. Note that information from the input medium may be input in a wireless manner.

  The display device 2060 includes a display unit (not shown) using, for example, a CRT, a liquid crystal display (LCD), a plasma display panel (PDP), and the like, and displays various information instructed by the control device 2040.

  The light receiver 2030 receives light from the two-dimensional array set in the two-dimensional array socket 2010 and outputs a signal (photoelectric conversion signal) corresponding to the amount of received light to the control device 2040. The light receiver 2030 has a plurality of light receiving elements or light receiving regions corresponding to a plurality of light emitting portions of the two-dimensional array.

  In the test, both the two-dimensional array socket 2010 and the light receiver 2030 are housed in a thermostatic bath in order to keep the temperature constant.

  As illustrated in FIG. 14, the control device 2040 includes a CPU 2041, a flash memory 2042, and a RAM 2043.

  The flash memory 2042 stores various programs described in codes that can be decoded by the CPU 2041.

  The RAM 2043 is a working memory.

  The CPU 2041 performs a predetermined process (hereinafter referred to as “continuous operation test process”) in accordance with the program stored in the flash memory 2042.

《Continuous operation test processing》
Here, the continuous operation test process performed by the CPU 2041 will be described with reference to FIGS. The flowcharts of FIGS. 15A to 15C correspond to a series of processing algorithms executed by the CPU 2041.

  When a continuous operation test request is received from the input device 2050, a program (hereinafter referred to as a “continuous operation test program”) corresponding to the flowcharts of FIGS. The start address is set in the program counter of the CPU 2041, and the continuous operation test process starts.

  It is assumed that the two-dimensional array to be tested has already been set in the two-dimensional array socket 2010 by the user. Moreover, the temperature of a thermostat shall be set to 90 degreeC.

  In the first step S501, information for specifying a two-dimensional array to be tested (for example, a model number) and an input request screen for various test conditions are displayed on the display unit of the display device 2060. As a result, the user inputs test conditions and the like via the input device 2050.

  In the next step S503, it is determined whether or not input of test conditions and the like has been completed. If the input of test conditions or the like has not been completed, the determination here is denied and the determination is made again after a certain period of time. If the input of the test conditions and the like has been completed, the determination here is affirmed and the process proceeds to step S505.

  In the next step S505, an initial value 1 is set to the counter n, and 40 is set to the number Num of light emitting units.

  In the next step S507, the light emitting unit vn which is the nth light emitting unit is set as the designated light emitting unit.

  In the next step S509, the designated light emitting unit is driven with a plurality of drive current values via the drive circuit 2020, and the current-light output characteristics of the designated light emitting unit are obtained from the output signal of the light receiver 2030 at each drive current value. To do.

  In the next step S511, the slope efficiency η is calculated from the current-light output characteristics of the designated light emitting unit.

  In the next step S513, a drive current value Ion corresponding to the planned light output Po is calculated.

  In the next step S515, it is determined whether or not the value of the counter n is smaller than the number of light emitting units Num. If the value of the counter n is smaller than the number of light emitting units Num, the determination here is affirmed and the process proceeds to step S517.

  In step S517, 1 is added to the value of the counter n, and the process returns to step S507.

  Thereafter, the processes in steps S507 to S517 are repeated until the determination in step S515 is denied.

  When the value of the counter n becomes equal to the number of light emitting units Num, the determination in step S515 is denied and the process proceeds to step S519.

  In step S519, all the light emitting units are driven (lighted) with the respective drive current values Ion via the drive circuit 2020.

  In the next step S521, when the light output is stabilized, the light output Pt at this time is acquired from the output signal of the light receiver 2030.

  In the next step S531, an initial value 1 is set to the counter n.

  In the next step S533, the light emitting unit vn is set as the target light emitting unit.

  In the next step S535, the target light emitting unit is turned off via the drive circuit 2020.

  In the next step S537, the optical output Ptd at this time is acquired from the output signal of the light receiver 2030.

  In the next step S539, the correction amount ΔIon of the drive current value Ion of the target light emitting unit is calculated using the above equation (1).

  In the next step S541, the corrected drive current value Ioc of the target light emitting unit is calculated using the above equation (2).

  In the next step S543, it is determined whether or not the drive current value Ioc is greater than or equal to a preset upper limit value Imax (for example, 10 mA). If the drive current value Ioc is less than Imax, the determination here is denied and the process proceeds to step S545.

  In step S545, it is determined whether the value of the counter n is smaller than the number of light emitting units Num. If the value of the counter n is smaller than the number of light emitting units Num, the determination here is affirmed and the process proceeds to step S547.

  In step S547, 1 is added to the value of the counter n, and the process returns to step S533.

  Thereafter, the processes in steps S533 to S547 are repeated until affirmative in step S543 or negative in step S545.

  When the value of the counter n becomes equal to the number of light emitting units Num, the determination in step S545 is denied and the process proceeds to step S549.

  In step S549, all the light emitting units are driven (lighted) at the respective drive current values Ioc via the drive circuit 2020.

  In the next step S551, when the light output is stabilized, the light output Pot at this time is acquired from the output signal of the light receiver 2030.

  In the next step S553, the optical output difference ΔP is calculated using the above equation (3).

  In the next step S561, it is determined whether or not ΔP is smaller than the allowable value ΔPo. If ΔP is not smaller than the allowable value ΔPo, the determination here is denied and the processing returns to step S531. On the other hand, if ΔP is smaller than the allowable value ΔPo, the determination here is affirmed, and the routine proceeds to step S563.

  In the next step S563, it is determined whether or not there is an end request from the user. If there is no termination request from the user, the determination here is denied and the process proceeds to step S511.

  In this step S565, it is determined whether or not the test time designated as one of the test conditions by the user has elapsed. If the designated test time has not elapsed, the determination here is denied, and the routine goes to Step S567. If the user does not specify the test time, a large value (for example, 400 hours) is set as the dummy for the test time.

  In step S567, it is determined whether a preset waiting time has elapsed. If the waiting time has not elapsed, the determination here is denied and the processing returns to step S563. On the other hand, if the waiting time has elapsed, the determination here is affirmed, and the routine goes to Step S569.

  In step S569, the value of Pot is set to Pt. Then, the process returns to step S531.

  If the drive current value Ioc is equal to or greater than Imax in step S543, the determination in step S543 is affirmed, and the process proceeds to step S569. In step S569, the test result (see FIGS. 16 and 17) is displayed on the display unit of the display device 2060. Then, the continuous operation test process ends.

  If there is an end request from the user in step S563, the determination in step S563 is affirmed, and the process proceeds to step S569.

  If the designated test time has elapsed in step S565, the determination in step S565 is affirmed, and the process proceeds to step S569.

  FIG. 16 shows the relationship between the energization time and the light output during full lighting. FIG. 17 shows the relationship between the energization time and the drive current value for each light emitting unit. In this case, it can be seen that, up to 130 hours, each drive current value increases with the energization time, but operates in the set light output range. Then, after 130 hours, the current suddenly increases and many light emitting portions that become defective frequently occur.

  As is clear from the above description, in the continuous operation test apparatus 2000 according to the present embodiment, the two-dimensional array socket 2010 constitutes a socket, the light receiver 2030 constitutes a photodetector, and the control apparatus 2040 constitutes a measuring apparatus. It is configured.

  It should be noted that at least a part of the processing according to the program by the CPU 2041 may be configured by hardware, or all may be configured by hardware.

  In the present embodiment, the test method according to the present invention is performed in the continuous operation test process.

  As described above, according to the continuous operation test apparatus 2000 according to the present embodiment, the light output of each light emitting unit in an environment very close to the full lighting state is measured by turning off the light emitting unit from the full lighting state. As a result, it is possible to measure the light output distribution in the two-dimensional array in the operating state, which has been difficult until now, and perform more accurate APC driving.

  Therefore, it is possible to accurately measure the characteristics of each light emitting part of the laser array having a plurality of light emitting parts.

  In the continuous operation test process, the slope efficiency η may be corrected as described above.

  In the continuous operation test process, as described above, a plurality of light emitting units may be set as target light emitting units at a time.

  As described above, the correction method of the present invention is suitable for correcting the drive current value of each light emitting unit of a laser array having a plurality of light emitting units individually with high accuracy. The light source device of the present invention is suitable for stably outputting a plurality of lights. Further, the program and the recording medium of the present invention are suitable for causing a computer for controlling the light source device to stably output a plurality of lights. Further, the optical scanning device of the present invention is suitable for performing stable optical scanning. The image forming apparatus of the present invention is suitable for forming a high quality image. In addition, the test apparatus and test method of the present invention are suitable for accurately measuring the characteristics of each light emitting part of a laser array having a plurality of light emitting parts.

FIG. 2 is a diagram for explaining a schematic configuration of a printer according to an embodiment of the invention. It is the schematic which shows the optical scanning device in FIG. It is a figure for demonstrating the light source in FIG. It is a figure for demonstrating the two-dimensional array in FIG. It is a figure for demonstrating the drive current correction circuit in FIG. It is a flowchart (the 1) for demonstrating a drive current value correction process. It is a flowchart (the 2) for demonstrating a drive current value correction process. It is a timing chart for explaining drive current value amendment processing. It is a flowchart for demonstrating the modification 1 of FIG.6 (B). 9 is a timing chart of drive current value correction processing corresponding to FIG. 8. It is a flowchart for demonstrating the modification 2 of FIG. 6 (B). It is a flowchart for demonstrating the modification 3 of FIG. 6 (B). It is a figure for demonstrating schematic structure of a tandem color machine. It is a figure for demonstrating schematic structure of the continuous operation | movement test process which concerns on one Embodiment of this invention. It is a figure for demonstrating the control apparatus in FIG. It is a flowchart (the 1) for demonstrating a continuous operation test process. It is a flowchart (the 2) for demonstrating a continuous operation | movement test process. It is a flowchart (the 3) for demonstrating a continuous operation | movement test process. It is FIG. (1) for demonstrating the result of a continuous operation | movement test process. It is FIG. (2) for demonstrating the result of a continuous operation | movement test process.

Explanation of symbols

  11a ... Scanning lens (part of scanning optical system), 11b ... Scanning lens (part of scanning optical system), 13 ... Polygon mirror (deflector), 14A ... Two-dimensional array (laser array), 14C ... Drive current correction Circuit (correction device), 25: light receiver (light detector), 1000: printer (image forming device), 1010 ... optical scanning device, 1010A: optical scanning device, 1030 ... photosensitive drum (image carrier), 1500 ... Tandem color machine (image forming apparatus), 2000 ... continuous operation test apparatus (test apparatus), 2010 ... two-dimensional array socket (socket), 2030 ... light receiver (photodetector), 2040 ... control apparatus (measurement apparatus), K1 , C1, M1, Y1... Photosensitive drum (image carrier).

Claims (11)

A correction method for correcting a drive current value of a laser array having a plurality of light emitting units,
Obtaining a slope efficiency of at least one light emitting part among the plurality of light emitting parts;
Lighting all of the plurality of light emitting units to obtain a total light output Pt;
Turning off the at least one light emitting unit and obtaining a total light output Ptd of all remaining light emitting units excluding the at least one light emitting unit;
Obtaining correction information of a drive current value of the at least one light emitting unit based on a difference between the light output Pt and the light output Ptd and the slope efficiency. In the step of obtaining the light output Ptd, at least some of the plurality of light emitting units are simultaneously turned off to obtain the light output Ptd,
In the step of acquiring the correction information, the correction information of the drive current values of the at least some of the plurality of light emitting units is respectively acquired based on the difference between the light output Pt and the light output Ptd and the slope efficiency. The correction method according to claim 1. Prior to the step of obtaining the light output Ptd, the step of obtaining the current-light output characteristic of the at least one light emitting unit while reducing the drive current value of the at least one light emitting unit and correcting the slope efficiency is further included. Including
In the step of acquiring the correction information, the correction information of the drive current value of the at least one light emitting unit is acquired based on the difference between the light output Pt and the light output Ptd and the corrected slope efficiency. The correction method according to claim 1, wherein the correction method is a characteristic of the correction method. A laser array having a plurality of light emitting portions;
A photodetector for receiving light emitted from the laser array;
All of the plurality of light emitting units are turned on to obtain a total light output Pt through the photodetector, at least one of the plurality of light emitting units is turned off, and the at least one light emitting unit is excluded. A total light output Ptd of all the remaining light emitting units is obtained through the photodetector, and based on the difference between the light output Pt and the light output Ptd and the slope efficiency of the at least one light emitting unit, the at least 1 A light source device comprising: a correction device that acquires correction information of drive current values of two light emitting units. A program used in a computer for controlling a light source device including a laser array having a plurality of light emitting units,
A procedure for determining a slope efficiency of at least one light emitting unit among the plurality of light emitting units;
A procedure for lighting all of the plurality of light emitting units to obtain a total light output Pt;
A procedure of turning off the at least one light emitting unit and obtaining a total light output Ptd of all the remaining ones excluding the at least one light emitting unit;
A program for causing the control computer to execute a procedure for acquiring correction information of a drive current value of the at least one light emitting unit based on a difference between the light output Pt and the light output Ptd and the slope efficiency.   A computer-readable recording medium on which the program according to claim 5 is recorded. An optical scanning device that scans a surface to be scanned with light,
A light source device according to claim 4;
A deflector for deflecting light output from the light source device;
A scanning optical system for condensing the light deflected by the deflector onto the surface to be scanned. At least one image carrier;
An image forming apparatus comprising: at least one optical scanning device according to claim 7, wherein the at least one image carrier is scanned with light including image information.   The image forming apparatus according to claim 8, wherein the image information is multicolor image information. A test apparatus for testing a laser array having a plurality of light emitting units,
A socket in which the laser array to be tested is set;
A photodetector for receiving light emitted from the laser array;
The light output Pt obtained from the light detector when all of the plurality of light emitting units are turned on, and the light output Ptd obtained from the light detector when only one of the light emitting units is sequentially turned off are measured. And a measuring device for obtaining a driving current value necessary for obtaining a predetermined light output based on a difference between the light output Pt and the light output Ptd and a slope efficiency for each light emitting unit. A test method for testing a laser array having a plurality of light emitting portions,
Obtaining a slope efficiency of at least one light emitting part among the plurality of light emitting parts;
Lighting all of the plurality of light emitting units to obtain a total light output Pt;
Turning off the light emitting part to be tested, and obtaining a total light output Ptd of all remaining light emitting parts excluding the at least one light emitting part;
Obtaining a driving current value necessary for obtaining a predetermined light output for the at least one light emitting unit based on a difference between the light output Pt and the light output Ptd and the slope efficiency. .

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