JP2008072068A - Laser light emitting device and optical scanning device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser light emitting device capable of emitting light of a constant output light intensity stabilized even if a temperature change is caused in a laser light emitting package, and to provide an optical scanning device using the laser light emitting device. <P>SOLUTION: A monitor current is outputted from a PD 4 when receiving back-side laser light 3 emitted accompanied by the start-up of an LD1, and the monitor current is corrected based on a temperature in a region 13 (a laser light emitting package) which houses the LD 1, the PD 4 and a temperature measuring device 5 with a cover 8 of the laser light emitting package 10, in which the temperature within the region 13 is detected by a temperature measuring device 5 at a correction circuit 21. A driving current for causing the LD 1 to emit light at a control circuit 22 is controlled based on the corrected monitor current. The controlled driving current is supplied to a driving circuit 23, where the driving current boots LD 1 to emit laser light in synchronization based on an external signal such as an image signal 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser light emitting device and an optical scanning device using the same.

  In a laser light emitting device used as an exposure unit of an image forming apparatus such as a laser printer, a laser diode that is a light source is a photo that detects a rear end side output light amount output from the laser diode in a laser light emitting package. This is integrated with the diode, and by detecting the output (monitor current) of this photodiode, the drive current of the laser diode that drives the laser diode to emit light is controlled and output from the laser diode. The amount of light is controlled and adjusted.

  However, due to the temperature rise in the laser light emitting package accompanying the light emission of the laser diode, the temperature of the laser diode and photodiode stored in the laser light emitting package changes. Due to this temperature change, a change in the ratio of the output light quantity in front of and behind the laser diode, a change in the oscillation wavelength of the drive current of the laser diode, and a change in the sensitivity of the photodiode occur. Due to these changes, for example, when the temperature in the laser light emitting package rises, the light emission characteristics of the laser diode deteriorate, and if the laser diode is driven with a constant monitor current of the photodiode, the output light quantity of the laser diode Is reduced, and it becomes impossible to perform appropriate printing.

As a countermeasure against this problem, a thermistor for detecting the temperature in the laser light emitting package is attached in the laser light emitting package, and the driving current of the laser diode is controlled based on the temperature in the laser light emitting package detected by the thermistor. (For example, Patent Document 1).
JP 2004-237633 A

  However, in the method described in Patent Document 1, since the drive current of the laser diode is directly controlled by the temperature detection output by the thermistor, the monitor current fluctuates with the temperature change of the photodiode housed in the laser light emitting package. Since this is not supported, there is a problem that the amount of light output from the laser diode is not stabilized, and good printing characteristics cannot be maintained.

  The present invention has been made in consideration of the above circumstances, and a laser light emitting device capable of emitting a stable and constant output light amount even when a temperature change in the laser light emitting package occurs, and optical scanning using the same. An object is to provide an apparatus.

In order to solve the above-mentioned problem, the invention described in claim 1 is provided with a laser light emitting package in which a laser diode and a photodiode for detecting the output light amount on the rear end side of the laser diode are integrated, and is detected by the photodiode. In the laser light emitting device comprising a control means for controlling the drive current of the laser diode based on the monitor current based on the output light quantity, the detecting means for detecting the temperature in the laser light emitting package, and the detection means Correction means for correcting the monitor current according to the detected temperature.
According to a second aspect of the present invention, in the laser light emitting device according to the first aspect, the detecting means is a temperature measuring element for detecting a temperature in the laser light emitting package, and the correcting means is the laser light emitting package. And a monitor current value relationship table at that temperature, and based on the relationship table, the reference monitor current value when the standard light amount is output from the laser diode is corrected.

According to a third aspect of the present invention, in the laser light emitting device according to the first aspect, the detecting means measures in advance based on the detected output light amount detected by the light amount detecting means for detecting the output light amount of the laser diode. The detected temperature is converted to a corresponding temperature from a relation table between the detected output light quantity and the temperature in the laser light emitting package.
According to a fourth aspect of the present invention, in the laser light emitting device according to the first aspect,
The detecting means measures the lighting time of the laser diode, and converts the measured lighting time into a corresponding temperature from a relation table between the lighting time measured in advance and the temperature in the laser light emitting package. The detected temperature is used.

According to a fifth aspect of the present invention, in the laser light emitting device according to the first aspect, the detection means detects the detected output light quantity detected by the light quantity detection means for detecting the output light quantity of the laser diode and the laser diode at that time. The laser emission start current is calculated from the input current value, and based on the laser emission start current, the laser emission start current is converted into the corresponding temperature from the preliminarily measured relationship table between the laser emission start current and the temperature in the laser emission package. The detected temperature is used.
According to a sixth aspect of the present invention, a latent image is formed by scanning a laser beam from the laser light emitting device including the laser diode according to any one of the first to fifth aspects one-dimensionally on the surface of the photosensitive member. It is characterized by forming.

  According to a seventh aspect of the present invention, there is provided an optical scanning device for forming a latent image by one-dimensionally scanning a laser beam from a laser light emitting device having a laser diode on the surface of the photosensitive member. Synchronization detecting means for detecting the laser beam, and the synchronization detecting means synchronizes the scanning start timing to the photosensitive member and the output timing of the laser beam from the laser diode, and is detected by the synchronization detecting means. The temperature inside the laser light emitting package in which the laser diode and the photodiode for detecting the output light amount on the rear end side of the laser diode are integrally detected is detected from the output light amount of the laser diode, and is detected by the photodiode according to the detected temperature. The monitor current due to the output light amount is corrected, and the laser diode is corrected based on the corrected monitor current. Wherein the driving current is controlled.

  According to an eighth aspect of the present invention, there is provided an optical scanning device for forming a latent image by one-dimensionally scanning a laser beam from a laser light emitting device having a laser diode on the surface of the photosensitive member. And a scanning time measuring means for detecting the scanning start timing and the scanning end laser beam of the one scanning line on the photosensitive member, and the scanning time measuring means measures the scanning time of one scanning line. The laser light emission that integrally stores the laser diode and the photodiode that detects the output light amount at the rear end side of the laser diode from the transmission wavelength is calculated from the measured scanning time and the transmission wavelength of the drive current supplied to the laser diode is calculated. The temperature inside the package is detected, and the monitor current due to the output light amount detected by the photodiode is corrected according to the detected temperature, and the corrected monitor power is corrected. Drive current of the laser diode is characterized in that it is controlled on the basis of.

  According to a ninth aspect of the present invention, there is provided an optical scanning device for forming a latent image by one-dimensionally scanning a laser beam from a laser light emitting device having a laser diode on the surface of the photosensitive member. And a synchronization detection means for detecting the laser beam, wherein the synchronization detection means synchronizes the scanning start timing of one scanning line to the photosensitive member and the output timing of the laser beam from the laser diode, and Based on the detection voltage of the synchronization detection signal detected by the synchronization detection means, the temperature in the laser light emitting package in which the laser diode and the photodiode for detecting the output light amount on the rear end side of the laser diode are integrated is detected, and the temperature is detected. The monitor current based on the output light amount detected by the photodiode is corrected, and the laser die is corrected based on the corrected monitor current. Wherein the driving current of over de is controlled.

  According to the present invention, there is provided a laser light emitting device capable of emitting a stable and constant output light amount even when a temperature change in the laser light emitting package occurs, and an optical scanning device using the same. It becomes possible to provide.

  In the present invention, as shown in FIG. 1, when the monitor current obtained by receiving the backward laser beam with a photodiode is fixed, the output light quantity of the laser diode driven based on this monitor current is the laser. It has been found that the temperature in the light emitting package decreases as the temperature increases. Based on this result, a monitor output by the photodiode corresponding to the detected temperature detected from the detecting means for detecting the temperature in the laser light emitting package for the variation in the output amount of the laser diode accompanying the temperature change in the laser light emitting package. The above object is achieved by correcting the driving current of the laser diode based on the current.

  In this case, as a means for detecting the temperature in the laser light emitting package, a temperature measuring element such as a thermocouple, thermistor, or photocoupler may be used to directly detect the temperature in the laser light emitting package. In this way, the fluctuation of the output wavelength of the laser diode and the drive current due to the temperature change in the laser light emitting package is detected, and the fluctuation is converted into a temperature change to indirectly change the temperature in the laser light emitting package. A detection method can also be employed. As described above, when using the method of indirectly detecting the temperature in the laser light emitting package, a new component such as a temperature measuring element is not used, and the synchronization detecting means in the optical scanning device is used as described later. This has the advantage that it can also be used as the temperature detecting means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a diagram showing the laser light emitting package unit 10 of the laser light emitting apparatus according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes a laser diode (hereinafter referred to as an LD) that outputs laser light to the front side 2 and the rear side 3, and reference numeral 4 denotes a photodiode (hereinafter referred to as a monitor current) that controls the drive current of the LD 1 by the rear side laser light 3. (Referred to as PD) 5 is a temperature measuring element such as a thermistor, 6 has LD1, PD4, and temperature measuring element 5 mounted on the upper surface, and has a connection terminal 7 connected to the LD1, PD4, and temperature measuring element on the lower surface. A base 8 is a cover attached to the upper surface of the base 6 and protects the LD 1, PD 4, temperature measuring element 5, etc. 9 is a front laser beam in which an opening drilled in the center of the cover 8 is sealed with glass Reference numerals 11 and 12 denote a reference surface and a flange formed on the upper surface of the base 6.

  As shown in FIG. 3, the laser light emitting device according to the first embodiment includes a driving circuit 20 for emitting laser light from the LD 1 together with the laser light emitting package unit 10 described above. , A correction circuit 21, a control circuit 22, and a drive circuit 23. The rear laser beam 3 emitted with the activation of the LD 1 is received and a monitor current is output from the PD 4. This monitor current is detected by the temperature measuring element 5 in the correction circuit 21 and covers the laser light emitting package unit 10. 8 is corrected based on the temperature in the region 13 (laser light emitting package) in which the LD1, the PD4, and the temperature measuring element 5 are accommodated. Based on the corrected monitor current, the control circuit 22 controls the drive current for causing the LD 1 to emit light. The drive current controlled in this way is supplied to the drive circuit 23, and the LD 1 is activated while synchronizing based on an external signal such as the image signal 24 to emit laser light.

  FIG. 4 is a diagram illustrating the relationship between the temperature in the laser light emitting package 13 and the monitor current output from the PD 4 when the output light amount of the front side laser light 2 output from the LD 1 is constant. Reference temperature immediately after manufacturing, TB is the temperature at the time of measurement, TC is the temperature at the time of use in a cold region, and IA (reference monitor current), IB, and IC are output at the temperatures at TA, TB, and TC, respectively. Monitor current. As is apparent from this figure, when the temperature in the laser light emitting package is raised by the light emission of the laser diode during measurement, the output light amount of the laser diode at the reference temperature must be corrected unless the monitor current for IB-IA is additionally corrected. Are not the same, and if the LD1 is driven with the reference monitor current IA, the amount of light is insufficient. On the other hand, when used in a cold region, if the laser diode is driven with the reference monitor current IA, the output light quantity becomes excessive. Therefore, the monitor current obtained by subtracting IA-IC from the reference monitor current IA. It becomes clear that it is necessary to correct to. In this case, as the reference temperature, select the temperature in the laser light emitting package immediately after the product is manufactured or immediately after the laser diode is not lit for a certain period of time, and use the monitor current at that time as the reference monitor current. Can do.

  In setting the reference monitor current IA, the reference monitor current is set using the output light quantity control device of the LD 1 shown in FIG. That is, in this control device, the LD 1 that is supplied with the voltage Vcc and outputs laser light outputs laser light with a light amount corresponding to the drive current flowing through the transistor Q and the resistor R. Further, the PD 4 generates a monitor current upon receiving the rear laser 3 of the LD 1. This monitor current is supplied to the input terminal P1 of the light quantity control circuit 15 as a voltage Vm. On the other hand, the control voltage Vcont is input to the input terminal P2 of the light amount control circuit 15, and the light amount control circuit 15 compares Vcont and Vm, and the transistor is output from the terminal P3 so that Vcont and Vm have the same voltage. The drive current of LD1 is controlled by controlling the base voltage of Q. Further, since Vm and the monitor current Im have a relationship of Vm = VR × Im, the monitor current Im and the control voltage Vcont have a proportional relationship as shown in FIG. Therefore, if a control voltage of VK is selected as the standard light amount now, ImK that intersects the proportional straight line in FIG. 6 becomes the reference monitor current. In this way, the reference monitor current is set when the apparatus is adjusted immediately after manufacture of the product. In FIG. 5, the terminal P4 of the light quantity control circuit is connected to the sample hold capacitor C.

Regarding the relationship of FIG. 4, immediately after manufacturing the product, a light receiving element 14 such as a photodiode is disposed on the front surface of the LD 1 as shown in FIG. 7, and the light receiving element 14 is irradiated with the front side laser light 2 from the LD 1. Then, the temperature in the laser light emitting package 13 can be changed, and the measurement can be performed by changing the monitor current so that the output light amount of the LD 1 becomes constant. This measurement result is stored and stored in a LUT (lookup table) in the correction circuit as a relationship table between the temperature in the laser light emitting package and the monitor current, and detected by the temperature measuring element 5 in the laser light emitting package 13 at the time of measurement. The drive current of the LD 1 can be controlled by obtaining the temperature and the monitor current corresponding to this temperature from the relation table in the LUT and correcting the reference monitor current.
As described above, the monitor current is corrected to the monitor current corresponding to the temperature measured by the temperature measuring element 5 in the laser light emitting package to control the drive current of the LD 1. Even if this occurs, a stable and constant output light quantity can be obtained.

In the second embodiment, unlike the case of the first embodiment described above, the temperature in the laser light emitting package 13 is detected indirectly without providing the temperature measuring element 5 in the laser light emitting package section 10 to monitor current. Is to be corrected.
That is, as described with reference to FIG. 1 above, when the LD 1 is driven with a constant monitor current, for example, a reference monitor current, the output light amount of the LD 1 changes with the temperature of the laser light emitting package 13 and this output The relationship between the light amount and the temperature is recorded and stored in the LUT in the correction circuit 21 as a relationship table. At the time of measurement, as shown in FIG. 7, the light receiving element 14 is installed on the front surface of the LD 1, and the output light amount of the LD 1 at the time of measurement is measured. From this output light amount, the relationship between the output light amount stored in the LUT and the temperature. The temperature is obtained from the table, and the correction amount of the monitor current is obtained from the relationship table between the monitor current and the temperature based on this temperature in the same manner as in the first embodiment. The drive current of the LD 1 is controlled based on the monitor current taking this correction amount into account. In this case, the light receiving element 14 need not always be attached to the laser light emitting device, and can be attached when necessary.
In the case of such a laser light emitting device, since a special device incorporating the temperature measuring element 5 such as the laser light emitting package portion 10 used in the first embodiment is not used, a general-purpose laser light emitting package portion 10 is used. Can be used and can be made inexpensive.

The third embodiment is an example in which the temperature in the laser light emitting package 13 is indirectly detected as in the second embodiment, and the temperature in the laser light emitting package 13 changes depending on the lighting time of the LD 1. Attention is paid to the temperature detection by measuring the lighting time of the LD1.
FIG. 8 shows the relationship between the lighting time of the LD 1 and the temperature in the laser light emitting package 13, and the temperature rises as the lighting time becomes longer. This relationship is stored as a relationship table in the LUT as in the case of the second embodiment, the lighting time is measured during measurement to determine the temperature, and the monitor current correction amount is determined in the same manner as in the second embodiment. .
By using such a laser light emitting device, the temperature in the laser light emitting package can be detected by a simple method, so that a cheaper device can be obtained.

In the fourth embodiment, similarly to the second embodiment described above, the temperature in the laser light emitting package 13 is indirectly detected, and the pulse transmission start current of the pulse driving current for driving the LD 1 is in the laser light emitting package 13. Focusing on the fluctuation in accordance with the temperature change, the pulse transmission start current is measured to detect the temperature.
FIG. 9 is a diagram showing the relationship between the pulse drive current of the LD 1 and the output light amount. Curve 1 shows an example when the temperature is 10 ° C., curve 2 shows 25 ° C., and curve 3 shows 60 ° C. As is clear from this figure, the pulse drive currents (transmission start current Ith) I10, I25, I60 when extrapolated at the extended portions of the curves at these temperatures to zero are changed according to the temperature, It is found that Ith increases with increasing temperature. From this relationship, as shown in FIG. 10, a relationship graph between the transmission start current and the temperature can be obtained. A relationship table between the transmission start current and temperature is stored in the LUT, and the temperature at the time of measurement can be obtained using this table. Based on the obtained temperature, the correction amount of the monitor current is obtained in the same manner as in the second embodiment.

  In addition, when calculating | requiring the transmission start current at the time of this measurement, as shown in FIG. 11, the light quantity in two measurement points a and b which changed the pulse drive current is measured, and these measurement points and pulse current values are measured. The transmission start current Ith at that temperature can be obtained by extrapolating from the above. Also in this case, as in the above-described third embodiment, the temperature can be detected without using a temperature measuring element or the like, so that the laser light emitting device can be manufactured at low cost.

  FIG. 12 is a diagram showing a schematic configuration of the optical scanning device according to the fifth embodiment of the present invention. Reference numeral 101 indicates that an external signal such as an image signal is modulated into a pulse width modulation signal, and the laser light emitting device 109 is modulated according to the external signal. LD modulator for controlling the output of the laser beam, 102 is a polygon scanner rotating at a constant speed, 103 is an fθ lens, 104 is a rotating photosensitive drum, and 105 is scanned in the direction of arrow A by the polygon scanner 102. A preceding synchronization detecting means for detecting a preceding synchronization signal by receiving a preceding beam of the scanning laser beam 110; a trailing synchronization detecting means for receiving a trailing beam of the scanning laser beam 110 and detecting a trailing synchronization signal; Reference numeral 107 denotes a travel time based on the detection signal DETP1 from the preceding synchronization detection means 105 and the detection signal DETP2 from the subsequent synchronization detection means 106. A time difference measuring unit for constant.

In the optical scanning device according to the fifth embodiment, the image signal is modulated into a pulse width modulation signal by the LD modulation device 101 to which the image signal is supplied, and laser light is emitted from the laser light emitting device 109 based on this modulation signal. The polarized laser beam 110 is scanned by the polygon scanner 102, converted into a constant velocity motion by the fθ lens 103, and scanned on the photosensitive drum 104 to produce an electrostatic latent image. The electrostatic latent image thus produced is made a visualized image by a developing device (not shown), and the visualized image is transferred to a transfer sheet and printed.
At this time, the leading and trailing portions of the scanning beam 110 forming the scanning line are detected by the leading synchronization detecting means 105 and the trailing synchronization detecting means 106, and the synchronization signals DETP1 and DETP2 are output. A time difference measuring unit 107 measures a time difference from these synchronization signals DETP1 and DETP2. The measured time difference is input to the LD modulator, and the transmission wavelength when the pulse modulation signal is formed is adjusted based on the time difference. At the same time, the synchronization signal DETP1 detected by the preceding synchronization detection means 105 is input to the LD modulator 101 to adjust the image signal to synchronize with the scanning timing on the photosensitive drum 104.

In the fifth embodiment, focusing on the fact that the transmission wavelength of the pulse signal adjusted by the time difference measured by the time difference measuring unit 107 varies depending on the temperature in the laser light emitting package 13, the laser light emitting package 13 from this transmission wavelength λ. As described in the first embodiment, the monitor current correction amount is obtained from the temperature stored in the LUT of the correction circuit 21 of the laser light emitting device and the monitor current. The drive current of the LD 1 is controlled based on the corrected monitor current.
FIG. 13 is a diagram showing the relationship between the transmission wavelength λ and the temperature in the laser light emitting package 13, and it is clear that the transmission wavelength λ increases as the temperature in the laser light emitting package 13 increases. From this relationship, it is possible to obtain the transmission wavelength from the time difference measured by the time difference measuring unit 107 and detect the temperature in the laser light emitting package 13 from this transmission wavelength.

  As described above, in the optical scanning device according to the fifth embodiment, the temperature in the laser light emitting package 13 is detected using the time difference in the time difference measuring unit 107, and the monitor current is corrected based on the detected temperature. Since an electrostatic latent image is produced on the photosensitive drum 104 using the laser light emitting device 109 that controls the drive current of the LD 1, the laser light emitting package 13 is always stable even if there is a temperature variation. Thus, it is possible to produce an electrostatic latent image with a certain amount of output light. In addition, since the time difference measuring unit 107 that adjusts the pulse wavelength of the pulse modulation signal is used as the laser light emitting device 109, an inexpensive optical scanning device can be obtained.

In the fifth embodiment, the time difference measuring unit 107 is used. However, the laser beam received by the synchronization detection units 105 and 106 using the preceding synchronization detection unit 105 and the subsequent synchronization detection unit 106 of the optical scanning device. 110, the temperature in the laser light emitting package 13 is detected from the amount of light received by the synchronization detecting means, and the monitor current is corrected from this temperature to detect the LD1. The drive current can be controlled.
In this case, as in the case of using the time difference measuring unit 107, the temperature in the laser light emitting package 13 is detected using the synchronization detection means, so that an inexpensive optical scanning device can be manufactured. In this case, only one of the synchronization detection means 105 and 106 may be used.
In the fifth embodiment, the time measurement unit 107 and the synchronization detection means 105 and 106 are used to detect the temperature in the laser light emitting package 13. However, the above-described first embodiment, third and fourth embodiments will be described. Similarly, it is possible to irradiate the photosensitive drum 104 with the laser beam 110 having a stable and constant output light amount from the laser light emitting device 109 also by the method of detecting the temperature in the laser light emitting package 13 by the above method.

In the sixth embodiment, the monitor current is corrected using one of the detection signals DETP1 and DETP2 detected by the synchronization detection means 105 and 106 described in the fifth embodiment.
FIG. 14 shows waveform diagrams of the detection signals DETP1 and DETP2. In these detection signals, the pulse 16 shown in FIG. 14 is generated, and this pulse 16 is usually detected and used as a synchronization signal. In the sixth embodiment, attention is paid to the drop voltage Vd of the pulse 16. This voltage drop Vd varies due to temperature variations in the laser light emitting package 13. Therefore, this drop voltage Vdc at the reference temperature is measured in advance, the reference drop voltage Vdc is compared with the drop voltage at the time of measurement, and the monitor current is set so that the drop voltage at the time of measurement is the same as the reference drop voltage Vdc. By adjusting and controlling the drive current of the LD 1, it is possible to obtain a laser beam 110 having a constant output light amount that is appropriately stable.
The optical scanning device according to the sixth embodiment does not require temperature conversion as described above, and thus has an advantage that the drive current of the LD 1 can be controlled more easily.

It is a graph which shows the relationship between the temperature in the laser light emitting package of the laser light emitting device when the monitor current is made constant, and the output light quantity. It is the perspective view which notched a part of laser light emitting package part of the laser light emitting apparatus which concerns on Embodiment 1 by this invention. It is a block diagram which shows schematic structure of the drive circuit of the laser beam emitting apparatus which concerns on Embodiment 1 by this invention. It is a graph which shows the relationship between the monitor electric current when the output light quantity used in the laser beam emission apparatus which concerns on Embodiment 1 by this invention is made constant, and the temperature in a laser emission package. It is a circuit diagram which shows schematic structure of the light quantity control apparatus used in the laser beam emitting apparatus concerning Embodiment 1 by this invention. It is a graph which shows the relationship between the control voltage and monitor current which are obtained in the light quantity control apparatus shown in FIG. It is a top view which shows schematic structure of the light quantity measuring apparatus used in the laser beam emitting apparatus concerning Embodiment 2 by this invention. It is a graph which shows the relationship between the lighting time of LD used in the laser-light-emitting device based on Embodiment 3 by this invention, and the temperature in a laser-light-emitting package. It is a graph which shows the relationship between the drive current of LD, and output light quantity for demonstrating the laser beam light-emitting device which concerns on Embodiment 4 by this invention. It is a graph which shows the relationship between the transmission start current of the laser light-emitting device concerning Embodiment 4 by this invention, and the temperature in a laser light-emitting package. It is a graph which shows the relationship between the drive current of LD for measuring the transmission start current of the laser beam emitting apparatus concerning Embodiment 4 by this invention, and an output light quantity. It is a figure which shows schematic structure of the optical scanning device which concerns on Embodiment 5 by this invention. It is a graph which shows the relationship between the temperature in the laser-light-emitting package of the laser-light-emitting device used with the optical scanning device concerning Embodiment 5 by this invention, and the transmission wavelength of a pulse modulation signal. It is a wave form diagram of the synchronous detection signal of the laser beam emitting apparatus used with the optical scanning device concerning Embodiment 6 by the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Laser diode, 2 Front side laser beam, 3 Back side laser beam, 4 Photodiode, 5 Temperature measurement element, 6 Base, 8 Cover, 10 Laser emission package part, 13 Laser emission package, 14 Light receiving element, 15 Light quantity control Circuit, 20 Drive circuit, 21 Correction circuit, 22 Control circuit, 23 Drive circuit, 24 Image signal, 101 LD modulator, 102 Polygon scanner, 103 fθ lens, 104 Photosensitive drum, 105 Pre-synchronization detection means, 106 Trailing synchronization Detection means, 107 time difference measuring unit, 109 laser light emitting device, 110 laser beam

Claims (9)

A laser light emitting package that integrally houses a laser diode and a photodiode that detects the output light amount on the rear end side of the laser diode, and the drive current of the laser diode is determined based on a monitor current based on the output light amount detected by the photodiode. In the laser light emitting device provided with the control means for controlling,
A laser light emitting device comprising: detecting means for detecting a temperature in the laser light emitting package; and correcting means for correcting the monitor current in accordance with a detected temperature detected from the detecting means. The laser light emitting device according to claim 1,
The detecting means is a temperature measuring element that detects a temperature in the laser light emitting package, and the correcting means includes a relationship table between the temperature in the laser light emitting package and a monitor current value at the temperature, and the relationship table includes And a reference monitor current value when the standard amount of light is output from the laser diode. The laser light emitting device according to claim 1,
The detection means corresponds from a relation table between the detected output light quantity measured in advance and the temperature in the laser light emitting package based on the detected output light quantity detected by the light quantity detection means for detecting the output light quantity of the laser diode. A laser light emitting device characterized by converting the temperature to the detected temperature. The laser light emitting device according to claim 1,
The detecting means measures the lighting time of the laser diode, and converts the measured lighting time into a corresponding temperature from a relation table between the lighting time measured in advance and the temperature in the laser light emitting package. A laser light emitting device having the detected temperature. The laser light emitting device according to claim 1,
The detection means calculates a laser light emission start current from the detected output light quantity detected by the light quantity detection means for detecting the output light quantity of the laser diode and the input current value of the laser diode at that time, and based on the laser light emission start current The laser light emitting device is characterized in that the detected temperature is converted into a corresponding temperature from a relation table between a laser light emission starting current measured in advance and a temperature in the laser light emitting package.   An optical scanning characterized in that a latent image is formed by scanning a laser beam from a laser light emitting device comprising the laser diode according to any one of claims 1 to 5 one-dimensionally on a surface of a photosensitive member. apparatus. In an optical scanning device that forms a latent image by scanning a laser beam from a laser light emitting device including a laser diode on a surface of a photosensitive member in a one-dimensional manner,
The optical scanning device includes synchronization detection means for detecting the laser beam, and the synchronization detection means synchronizes the scanning start timing to the photoconductor and the output timing of the laser beam from the laser diode, and the synchronization The temperature in the laser light emitting package in which the laser diode and the photodiode for detecting the output light amount on the rear end side of the laser diode are integrated is detected from the output light amount of the laser diode detected by the detecting means, and the photo is detected according to the detected temperature. An optical scanning device characterized in that a monitor current due to the output light amount detected by a diode is corrected, and a drive current of the laser diode is controlled based on the corrected monitor current. In an optical scanning device that forms a latent image by scanning a laser beam from a laser light emitting device including a laser diode on a surface of a photosensitive member in a one-dimensional manner,
The optical scanning device includes a scanning time measuring unit that detects a scanning start timing and a scanning end laser beam of one scanning line on the photosensitive member, and the scanning time measuring unit scans one scanning line. The time is measured, the transmission wavelength of the drive current supplied to the laser diode is calculated from the measured scanning time, and the laser diode and the photodiode for detecting the output light amount on the rear end side of the laser diode are integrated from the transmission wavelength. The temperature in the laser light emitting package housed in the sensor is detected, and the monitor current based on the output light amount detected by the photodiode is corrected according to the detected temperature, and the drive current of the laser diode is corrected based on the corrected monitor current Is controlled, an optical scanning device. In an optical scanning device that forms a latent image by scanning a laser beam from a laser light emitting device including a laser diode on a surface of a photosensitive member in a one-dimensional manner,
The optical scanning device includes synchronization detection means for detecting the laser beam, and the synchronization detection means determines the scanning start timing of one scanning line to the photosensitive member and the output timing of the laser beam from the laser diode. Synchronize and detect the temperature in the laser light emitting package integrally housing the laser diode and the photodiode for detecting the output light amount on the rear end side of the laser diode from the detection voltage of the synchronization detection signal detected by the synchronization detection means, An optical scanning device characterized in that a monitor current based on an output light amount detected by a photodiode is corrected according to the detected temperature, and a drive current of the laser diode is controlled based on the corrected monitor current.

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