JP2013055152A - Surface emitting laser unit, optical scanner, and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface emitting laser unit which enables the downsizing and highly accurate light quantity monitoring at low cost.SOLUTION: A surface emitting laser unit comprises: a surface emitting laser element 10 where multiple surface emitting lasers are formed; a light receiving element 20 receiving a part of laser light emitted from the surface emitting lasers; a package part 30 and a cap 40 which cover the surface emitting laser element and the light receiving element; and a control part controlling the surface emitting laser element on the basis of the output obtained by the light receiving element. A transparent member 41, allowing the laser light emitted from the surface emitting lasers to transmit, is provided at the cap part, and the part of the laser light emitted from the surface emitting lasers is reflected at the transparent member and incident into the light receiving element. Multiple groups of surface emitting lasers, which include a part of the multiple surface emitting lasers, are provided at the surface emitting laser element.

Description

  The present invention relates to a surface emitting laser unit, an optical scanning device, and an image forming apparatus.

  In recent years, higher-definition image quality is required in multicolor image forming apparatuses. For this reason, the speed is increasing year by year and it is being used for simple printing as an on-demand printing system. In such an image forming apparatus, by using a two-dimensional array element in which surface emitting lasers (VCSEL: Vertical Cavity Surface Emitting LASER) are two-dimensionally arranged, the sub-scanning interval on the photosensitive member is set to the recording density. 1 / n, and the unit pixel can form a matrix structure of n × m dots. Further, it is possible to simultaneously scan with a plurality of light beams.

  Usually, since a semiconductor laser used for optical writing performs APC (Automatic Power Control) control, it is necessary to monitor the light emission amount of the semiconductor laser. With an edge-emitting laser, the amount of light can be monitored by receiving light emitted from the end surface opposite to the light emitting end. However, with a surface-emitting laser, light is emitted to the surface opposite to the emitting surface. Is not emitted, the amount of light cannot be monitored by a method similar to that of the edge emitting laser. Therefore, in the surface emitting laser, various methods for branching a part of the emitted light and monitoring the light amount have been studied and disclosed.

  For example, Patent Document 1 discloses a method in which a beam spiriter is disposed on the emission surface side of a surface emitting laser, light emitted from the surface emitting laser is branched by the beam spiriter, and is detected by a photodetector as monitor light. Has been.

  Further, in Patent Document 2, an aperture formed by a mirror is provided on the exit slope side of the surface emitting laser, and is separated into light passing through the aperture and light reflected by the mirror provided in the aperture, and provided in the aperture. A method of detecting and monitoring light reflected by a reflected mirror with a light receiving element is disclosed.

  However, since the method described in Patent Document 1 is a method of branching light to be used by a beam splitter, the light utilization efficiency is lowered, and the beam splitter is expensive, leading to an increase in cost. Have the following problems.

  In addition, the method described in Patent Document 2 requires special optical components, or requires optical components for making light incident on the light receiving element. Similarly, the cost increases and the size increases. Have the problem of

  Furthermore, there is a method in which a VCSEL array and a light receiving element are mounted adjacent to each other on the package and the reflected light from the exit window is monitored. Thus, there is a problem that the position of the reflected light on the light receiving element is deviated and correct APC control cannot be performed.

  In this method, since it is difficult to adjust the light receiving position after sealing the package, a package whose light receiving position is out of position must be discarded after being mounted, which increases the manufacturing cost. As a means for solving this, a method such as enlarging the light receiving element is conceivable. However, if a large light receiving element is used, the package size is increased accordingly, and the surface emitting laser module is increased. A problem occurs.

  Further, while the laser beam used for writing is light that has passed through the aperture, the light amount monitor monitors the entire beam spot of the laser beam, and thus there is a problem that the APC accuracy deteriorates.

  The present invention has been made in view of the above, and an object thereof is to provide a surface-emitting laser unit that can be miniaturized at a low cost and capable of monitoring a light amount with high accuracy. It is another object of the present invention to provide an optical scanning apparatus and an image forming apparatus that can form a high-quality image with high reliability.

  The present invention includes a surface emitting laser element in which a plurality of surface emitting lasers are formed, a light receiving element that receives a part of laser light emitted from the surface emitting laser, the surface emitting laser element, and the light receiving element. And a control unit that controls the surface-emitting laser element based on an output obtained by the light-receiving element, and the cap unit includes a laser beam emitted from the surface-emitting laser. A part of the laser light emitted from the surface emitting laser is reflected by the transparent member and is incident on the light receiving element, and the surface emitting laser element includes A plurality of surface emitting laser groups including a part of the plurality of surface emitting lasers are provided, and the controller emits the surface emitting laser and outputs detected by the light receiving element. Based on Nita signal, from the group of the plurality of surface emitting lasers, and selects a group of one of the surface emitting laser.

  The present invention also provides a surface-emitting laser element in which a plurality of surface-emitting lasers are formed, a light-receiving element that receives a part of laser light emitted from the surface-emitting laser, the surface-emitting laser element, and the light-receiving element And a control unit that controls the surface-emitting laser element based on an output obtained by the light-receiving element, and the cap part is emitted from the surface-emitting laser. A transparent member that transmits laser light is provided, and a part of the laser light emitted from the surface emitting laser is reflected by the transparent member and is incident on the light receiving element. The surface emitting light is divided into a plurality of regions, and the control unit emits the surface emitting laser and emits the surface light based on output monitor signals detected by the plurality of regions in the light receiving element. And selects the area of the light receiving elements corresponding to the over THE.

  According to the present invention, it is possible to provide a surface emitting laser unit that can be miniaturized at a low cost and can monitor a light amount with high accuracy. Furthermore, by using this surface emitting laser unit, Therefore, it is possible to provide an optical scanning apparatus and an image forming apparatus that can form a high-quality image with high reliability.

Configuration diagram of a surface emitting laser module according to the first embodiment Explanatory drawing of the surface emitting laser module in 1st Embodiment Explanatory drawing of the surface emitting laser unit in 1st Embodiment Explanatory drawing of the surface emitting laser element in 1st Embodiment Explanatory drawing (1) of the correction | amendment method of the surface emitting laser unit in 1st Embodiment Explanatory drawing (2) of the correction method of the surface emitting laser unit in 1st Embodiment Explanatory drawing (3) of the correction | amendment method of the surface emitting laser unit in 1st Embodiment Explanatory drawing of the other surface emitting laser element in 1st Embodiment Explanatory drawing of the surface emitting laser unit in 2nd Embodiment Explanatory drawing (1) of the correction method of the surface emitting laser unit in 2nd Embodiment Explanatory drawing (2) of the correction | amendment method of the surface emitting laser unit in 2nd Embodiment Explanatory drawing (3) of the correction method of the surface emitting laser unit in 2nd Embodiment Explanatory drawing of the surface emitting laser unit in 3rd Embodiment Explanatory drawing (1) of the correction method of the surface emitting laser unit in 3rd Embodiment Explanatory drawing (2) of the correction | amendment method of the surface emitting laser unit in 3rd Embodiment Explanatory drawing of the surface emitting laser unit in 4th Embodiment Explanatory drawing of the other surface emitting laser unit in 4th Embodiment Configuration diagram of laser printer in fifth embodiment Configuration of Optical Scanning Device in Fifth Embodiment Configuration diagram of color printer according to sixth embodiment

  The form for implementing this invention is demonstrated below. In addition, about the same member etc., the same code | symbol is attached | subjected and description is abbreviate | omitted.

[First Embodiment]
The surface emitting laser module and the surface emitting laser unit according to the first embodiment will be described. As shown in FIGS. 1 and 2, in the surface emitting laser module according to the present embodiment, the light receiving element 20 formed by the surface emitting laser element 10 and the photodiode is covered with a package part 30 and a cap part 40. Yes. 1 is a view of the inside of the surface emitting laser module according to the present embodiment as seen from the side, and FIG. 2 is a view of the inside as seen from the top, that is, a top view with the cap portion 40 removed. It is.

  The surface emitting laser element 10 and the light receiving element 20 are installed on the concave bottom surface of the package unit 30. A wiring 31 is provided on the bottom surface of the package unit 30, the surface emitting laser element 10 and the wiring 31 are connected by a bonding wire 32, and the light receiving element 20 and the wiring 31 are connected by a bonding wire 33. Yes.

  The cap portion 40 is entirely made of a metal material, but the transparent member 41 made of a material such as glass is applied to the region irradiated with the laser light emitted from the surface emitting laser in the surface emitting laser element 10. Is provided. The transparent member 41 transmits most of the laser light emitted from the surface emitting laser, but about 10% of light is reflected on the front and back surfaces of the transparent member 41. In this manner, the light reflected by the transparent member 41 is formed with an angle θ with respect to the surface of the surface emitting laser element 10 so that the light is incident on the light receiving element 20. In the present embodiment, the angle θ is about 19 °. Moreover, the package part 30 and the cap part 40 are joined by seam welding, and are sealed by this.

  Next, as shown in FIG. 3, the control of the surface emitting laser module in the present embodiment will be described. A wiring 31 provided in the package unit 30 is connected to a wiring (not shown) outside the package unit 30, and a wiring outside the package unit 30 is connected to a write control unit 50 having a write control circuit or the like. Yes. In the present embodiment, a surface emitting laser unit is formed by the surface emitting laser module and the writing control unit 50.

  The light detected by the light receiving element 20 is converted into an electrical signal and then input to the write control unit 50 as an output monitor signal via the wiring 31 and the like. The writing control unit 50 detects the light intensity of the laser light applied to the light receiving element 20 based on the output monitor signal, compares the light intensity with a reference value, and compares the light intensity with the surface emitting laser in the surface emitting laser element 10. The amount of current is adjusted so that the intensity of the emitted laser light becomes a predetermined value, and is input to the surface emitting laser element 10 as a writing signal. The value of this writing signal is held until the next output monitor signal is detected and the amount of current flowing through the surface emitting laser element 10 is adjusted based on the output monitor signal. The output of the emitted laser light can be kept constant.

  Next, the surface emitting laser formed in the surface emitting laser element 10 will be described. In the present embodiment, as shown in FIG. 4, the surface emitting laser element 10 is formed with a two-dimensional surface emitting laser array and has 8 × 6 surface emitting lasers 11. In this surface emitting laser element 10, the number of surface emitting lasers 11 used for optical writing or the like is 8 × 4.

  In the surface emitting laser unit according to the present embodiment, in such a surface emitting laser element 10, the six surface emitting lasers 11a, 11b, 11c, 11d, 11e, and 11f shown in the region 4A in FIG. Based on the light quantity of the light that is emitted by and partially reflected by the transparent member 41 and enters the light receiving element 20, it is selected which of the surface emitting laser groups 12a, 12b, and 12c to be used is used.

  For example, as shown in FIG. 5, when the light receiving element 20 is installed at a desired position with respect to the surface emitting laser element 10, that is, emitted from a surface emitting laser located substantially at the center of the surface emitting laser element 10. When light is received at substantially the center of the light receiving element 20, the surface emitting laser group 12a in the central portion of the surface emitting laser array in FIG. 4 is selected and used. Specifically, as shown in FIG. 5A, when the light receiving element 20 is installed at a desired position with respect to the surface emitting laser element 10, the surface emitting lasers 11a, 11b, 11c in the region 4A, When 11d, 11e, and 11f are caused to emit light, as shown in FIG. 5B, the light receiving element 20 detects the monitor current value of the laser light emitted from the surface emitting laser 11c or 11d as the highest value. . Therefore, in this case, in the surface emitting laser element 10, the surface emitting laser group 12a in the central portion of the surface emitting laser array is selected and used. Information indicating that the surface emitting laser group 12 a has been selected in the surface emitting laser element 10 is stored as a parameter in the write control unit 50.

  Further, as shown in FIG. 6, in the drawing, when the light receiving element 20 is installed at a position shifted to the right side with respect to the light spot by the surface emitting laser element 10, the right side of the surface emitting laser array in FIG. The surface emitting laser group 12b in the portion is selected and used. Specifically, as shown in FIG. 6A, when the light receiving element 20 is installed at a position shifted to the right side with respect to the light spot by the surface emitting laser element 10, the surface emitting laser 11a in the region 4A. , 11b, 11c, 11d, 11e, and 11f, as shown in FIG. 6B, monitor current values of laser beams emitted from the surface emitting lasers 11d, 11e, and 11f detected by the light receiving element 20 However, it becomes higher than the monitor current value of the laser light emitted from the surface emitting lasers 11a, 11b, and 11c. Therefore, in this case, in the surface emitting laser element 10, the surface emitting laser group 12b in the right portion of the surface emitting laser array is selected and used. Information indicating that the surface emitting laser group 12 b has been selected in the surface emitting laser element 10 is stored as a parameter in the write control unit 50.

  As shown in FIG. 7, in the drawing, when the light receiving element 20 is installed at a position shifted to the left side with respect to the light spot by the surface emitting laser element 10, the left side portion of the surface emitting laser array in FIG. The surface emitting laser group 12c in FIG. Specifically, as shown in FIG. 7A, when the light receiving element 20 is installed at a position shifted to the left with respect to the light spot by the surface emitting laser element 10, the surface emitting laser 11a in the region 4A. , 11b, 11c, 11d, 11e, and 11f, as shown in FIG. 7B, the monitor current value of the laser light emitted from the surface emitting lasers 11a, 11b, and 11c detected by the light receiving element 20 However, it becomes higher than the monitor current value of the laser light emitted from the surface emitting lasers 11d, 11e, and 11f. Therefore, in this case, in the surface emitting laser element 10, the surface emitting laser group 12c in the left portion of the surface emitting laser array is selected and used. Information indicating that the surface emitting laser group 12c is selected in the surface emitting laser element 10 is stored as a parameter in the writing control unit 50.

  As described above, the surface emitting lasers 11 a, 11 b, 11 c, 11 d, 11 e, and 11 f are sequentially made to emit light with substantially the same light amount, and the light that is partially reflected by the transparent member 41 by the light receiving element 20 Based on the monitor current value detected and detected by the light receiving element 20, one of the group of surface emitting lasers 12a, 12b, 12c to be used in the surface emitting laser array in the surface emitting laser element 10 is selected. Thereby, the APC operation can be performed in a state where the position of the monitor light received by the light receiving element 20 is optimized. In the present embodiment, the surface emitting laser groups 12a, 12b, and 12c may also be described as surface emitting laser arrays.

  In the above description, the left and right positional shifts have been described in the drawings. However, the same method can be used for vertical positional shifts. Specifically, the surface emitting laser element 10 is also provided with surface emitting lasers 11 in the vertical direction, that is, as shown in FIG. 8, 10 × 6 surface emitting lasers 11 are provided in the surface emitting laser element 10. By selecting a group of 8 × 4 surface emitting lasers by the same method, it is possible to further correct the positional deviation in the vertical direction. The surface emitting laser element shown in FIG. 8 can cope with vertical and horizontal positional shifts.

[Second Embodiment]
Next, a second embodiment will be described. In this embodiment, the light receiving element is divided into a plurality of regions. Based on FIG. 9, the surface emitting laser module and the surface emitting laser unit in the present embodiment will be described. In the surface emitting laser module according to the present embodiment, the surface emitting laser element 10 is formed with a two-dimensional surface emitting laser array and has 8 × 3 surface emitting lasers 11. The light receiving element 20 is divided into a plurality of regions 21, 22, 23, 24, and 25.

  Each of the divided regions 21, 22, 23, 24, and 25 is connected to the light receiving element region selecting unit 60, and the light receiving element region selecting unit 60 is connected to the writing control unit 50. The light receiving element region selection unit 60 selects any one of the regions 21, 22, 23, 24, and 25 in the light receiving element 20, outputs an output monitor signal from the selected region to the write control unit 50, The amount of light emitted from the surface emitting laser element 10 is controlled by controlling the current flowing through the light emitting laser. The surface emitting laser unit in the present embodiment includes a surface emitting laser module, a light receiving element region selecting unit 60, and a writing control unit 50.

  Next, in the surface emitting laser unit according to the present embodiment, the surface emitting laser 11g in the surface emitting laser element 10 is corrected with respect to a method of correcting the relative displacement of the light receiving element 20 with respect to the surface emitting laser in the surface emitting laser element 10. The case where light is emitted will be described as an example with reference to FIGS.

  As shown in FIG. 10, when the light receiving element 20 is installed at a desired position with respect to the surface emitting laser element 10, the light receiving element 20 is used to detect monitor light when the surface emitting laser 11g emits light. The region 23 is selected and used. Specifically, as shown in FIG. 10, when the light receiving element 20 is installed at a desired position with respect to the surface emitting laser element 10, when the surface emitting laser 11g emits light, the central portion of the light receiving element 20 is obtained. The monitor current value detected in the region 23 is the highest. Therefore, in this case, when the surface emitting laser 11g emits light, the output monitor signal detected in the region 23 in the light receiving element 20 is used. Information that the region 23 is selected in the light receiving element 20 when the surface emitting laser 11g emits light is stored as a parameter in the write control unit 50.

  As shown in FIG. 11, in the drawing, when the light receiving element 20 is installed at a position slightly shifted to the right side with respect to the light spot by the surface emitting laser element 10, the surface emitting laser 11g is caused to emit light. In this case, the region 22 in the light receiving element 20 is selected and used for detecting the monitor light. Specifically, as shown in FIG. 11, when the light receiving element 20 is installed at a position slightly shifted to the right with respect to the light spot by the surface emitting laser element 10, when the surface emitting laser 11g emits light, The monitor current value detected in the region 22 of the light receiving element 20 is the highest. Therefore, in this case, when the surface emitting laser 11g emits light, the output monitor signal detected in the region 22 in the light receiving element 20 is used. Information indicating that the region 22 in the light receiving element 20 is selected when the surface emitting laser 11g emits light is stored as a parameter in the write control unit 50.

  As shown in FIG. 12, in the drawing, when the light receiving element 20 is installed at a position slightly shifted to the left side with respect to the light spot by the surface emitting laser element 10, the surface emitting laser 11g is caused to emit light. In this case, the region 24 in the light receiving element 20 is selected and used for detecting the monitor light. Specifically, as shown in FIG. 12, when the light receiving element 20 is installed at a position slightly shifted to the left with respect to the light spot by the surface emitting laser element 10, when the surface emitting laser 11g emits light, The monitor current value detected in the region 24 of the light receiving element 20 is the highest. Therefore, in this case, when the surface emitting laser 11g emits light, the output monitor signal detected in the region 24 in the light receiving element 20 is used. Information indicating that the region 24 in the light receiving element 20 is selected when the surface emitting laser 11g emits light is stored as a parameter in the write control unit 50.

  By the above-described method, correction of the relative displacement of the light receiving element 20 with respect to the surface emitting laser is performed for all the surface emitting lasers in the surface emitting laser element 10, that is, in the case shown in FIG. 9, 8 × 3 surface emitting lasers. Then, each region of the light receiving element 20 selected in each surface emitting laser is stored in the write control unit 50. Thus, by selecting each region used in the light receiving element 20 and using the output monitor signal in that region, the light receiving position of the monitor light is optimized, so that the accuracy of the APC operation can be improved.

  In the above description, as shown in FIG. 9 and the like, the case where the region of the light receiving element 20 is divided vertically to correct the positional deviation in the left-right direction has been described. However, the region of the light receiving element 20 is divided horizontally. By doing so, it is possible to cope with the correction of the positional deviation in the vertical direction.

  The contents other than those described above are the same as those in the first embodiment.

[Third Embodiment]
Next, a third embodiment will be described. This embodiment is the same as the surface emitting laser module and the surface emitting laser unit in the second embodiment, and is a surface emitting laser element in which the interval between adjacent surface emitting lasers is narrow, specifically, FIG. As shown in FIG. 13, this corresponds to the surface emitting laser element 10 in which the distance between the surface emitting laser 11g and the surface emitting laser 11h is narrow.

  As shown in FIG. 14, among the monitor current values detected in the respective regions 21, 22, 23, 24, and 25 in the light receiving element 20 when the surface emitting laser 11 g emits light, the monitor detected in the region 23. When the current is maximum, when the surface emitting laser 11g is caused to emit light, most of the light spot is formed on the region 23, and therefore, the output monitor signal detected in the region 23 of the light receiving element 20 is used. . Information that the region 23 is selected in the light receiving element 20 when the surface emitting laser 11g emits light is stored as a parameter in the write control unit 50.

  As shown in FIG. 15, among the monitor current values detected in the respective regions 21, 22, 23, 24, and 25 in the light receiving element 20 when the surface emitting laser 11 h is caused to emit light, the regions 22 and 23. When the surface emitting laser 11h is caused to emit light, the light spot is formed across the region 22 and the region 23. Therefore, the output monitor detected in the region 22 of the light receiving element 20 is detected. An output monitor signal that is the sum of the signal and the output monitor signal detected in the region 23 is used. When the surface emitting laser 11h is caused to emit light in this way, the region 22 and the region 23 are selected in the light receiving element 20, and information indicating that the output monitor signal of the sum of these regions is used is set in the parameter in the write control unit 50. Saved as

  Thereby, in the present embodiment, the light receiving region in the light receiving element 20 can be finely adjusted even in the surface emitting laser element 10 in which the interval between the surface emitting lasers is narrow.

[Fourth Embodiment]
Next, a fourth embodiment will be described. In the present embodiment, regions divided in the light receiving element 20 are formed corresponding to the shape of the aperture through which the laser light emitted from the surface emitting laser module passes.

  This embodiment will be described with reference to FIG. Usually, in an image forming apparatus or the like, light that has passed through an aperture 70 among laser light emitted from a surface emitting laser module is used. For this reason, in the present embodiment, the light receiving element 20 detects the amount of light corresponding to the laser light that has passed through the aperture 70, thereby performing a more appropriate APC operation. FIG. 16A shows the corresponding relative relationship between the surface emitting laser element 10 and the aperture 70 for convenience, and does not show the actual installation position.

  As shown in FIG. 16A, the laser beam 15 emitted from the surface emitting laser in the surface emitting laser element 10 is partially blocked by the aperture 70 having an opening 71 having a predetermined shape. The laser beam that has passed through the opening 71 is used as a laser beam having a predetermined shape for various purposes. For example, as shown in FIG. 16A, the opening 71 provided in the aperture 70 is formed long in the vertical direction as indicated by an arrow. In this case, the regions 21, 22, 23, 24 and 25 divided in the vertical direction in the light receiving element 20 are formed so as to be close to the shape of the opening 71 in the aperture 70. That is, the light receiving element 20 is formed so that the longitudinal direction of the opening 71 in the aperture 70 and the longitudinal direction of the regions 21, 22, 23, 24, and 25 in the light receiving element 20 are the same.

  In this way, the longitudinal direction of the opening 71 in the aperture 70 and the longitudinal direction of the shape in each of the regions 21, 22, 23, 24, and 25 in the light receiving element 20 are matched to pass through the opening 71 in the aperture 70. The amount of light corresponding to the laser beam to be detected can be detected in any of the regions. That is, as shown in FIG. 16B, in the light receiving element 20, the light 16 corresponding to the laser light that has passed through the opening 71 of the aperture 70 out of the light spot 15 a of the laser light irradiated on the light receiving element 20. Is detected in the region 23 having a shape close to the shape of the opening 71 of the aperture 70. Therefore, even when a change occurs in the FFP (Far Field Pattern) characteristics and the intensity distribution of the light spot, a good APC operation can be performed with high accuracy.

  In the above description, the case where the longitudinal direction of the opening 71 in the aperture 70 is the longitudinal direction has been described, but the same applies to the case where the lateral direction is the longitudinal direction. Specifically, as shown in FIG. 17A, the opening 171 of the aperture 170 is formed long in the lateral direction as indicated by an arrow. In this case, the regions 121, 122, 123, 124, and 125 divided in the horizontal direction in the light receiving element 20 are formed so as to be close to the shape of the opening 171 in the aperture 170. That is, the light receiving element 20 is formed so that the longitudinal direction of the opening 171 in the aperture 170 and the longitudinal direction of the regions 121, 122, 123, 124, 125 in the light receiving element 20 are the same. FIG. 17A shows the corresponding relative relationship between the surface emitting laser element 10 and the aperture 170 for convenience, and does not show the actual installation position.

  In this way, the longitudinal direction of the opening 171 in the aperture 170 and the longitudinal direction of the shape in each of the regions 121, 122, 123, 124, and 125 in the light receiving element 20 are matched to pass through the opening 171 in the aperture 170. The amount of light corresponding to the laser beam to be detected can be detected in any of the regions. That is, as shown in FIG. 17B, in the light receiving element 20, the light 116 corresponding to the laser light that has passed through the opening 171 of the aperture 170 out of the light spot 15 a of the laser light irradiated on the light receiving element 20 is , In the region 123 having a shape close to the shape of the opening 171 of the aperture 170. Therefore, even when a change occurs in the FFP characteristic or the intensity distribution of the light spot, a good APC operation can be performed with high accuracy. The contents other than the above are the same as in the second or third embodiment.

[Fifth Embodiment]
Next, a fifth embodiment will be described. The present embodiment is a laser printer 1000 as an image forming apparatus using any one of the surface emitting laser units in the first to fourth embodiments.

  Based on FIG. 18, a laser printer 1000 according to the present embodiment will be described. The laser printer 1000 according to this embodiment includes an optical scanning device 1010, a photosensitive drum 1030, a charging charger 1031, a developing roller 1032, a transfer charger 1033, a charge eliminating unit 1034, a cleaning unit 1035, a toner cartridge 1036, a paper feeding roller 1037, a feeding roller. A paper tray 1038, a registration roller pair 1039, a fixing roller 1041, a paper discharge roller 1042, a paper discharge tray 1043, a communication control device 1050, and a printer control device 1060 that comprehensively controls each of the above parts are provided. These are housed in predetermined positions in the printer housing 1044.

  The communication control device 1050 controls bidirectional communication with a host device (for example, a personal computer) via a network or the like.

  The photosensitive drum 1030 is a cylindrical member, and a photosensitive layer is formed on the surface thereof. That is, the surface of the photoconductor drum 1030 is a scanned surface. The photosensitive drum 1030 rotates in the direction indicated by the arrow X.

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

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

  The optical scanning device 1010 scans the surface of the photosensitive drum 1030 charged by the charging charger 1031 with a light beam modulated based on image information from the host device, and corresponds to the image information on the surface of the photosensitive drum 1030. A latent image is formed. 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.

  Toner cartridge 1036 stores toner, and this toner is supplied to 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. 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 unit 1035 removes the toner remaining on the surface of the photosensitive drum 1030 (residual toner). The surface of the photosensitive drum 1030 from which the residual toner has been removed returns to the position facing the charging charger 1031 again.

  Next, the optical scanning device 1010 will be described with reference to FIG. The optical scanning device 1010 collectively includes a light source unit 1100, a coupling lens 1111, an aperture 1112, a cylindrical lens 1113, a polygon mirror 1114, an fθ lens 1115, a toroidal lens 1116, two mirrors (1117, 1118), and the above parts. A control device (not shown) for controlling is provided. As the light source unit 1100, the light source unit 1100 including any one of the surface emitting laser units in the first to fourth embodiments is used. Further, the aperture 70 and the like in the fourth embodiment correspond to the aperture 1112 in the present embodiment.

  The coupling 1111 shapes the laser light emitted from the surface emitting laser in the light source unit 1100 into substantially parallel light.

  The aperture 1112 defines the laser light from the coupling lens 1111 so as to have a predetermined beam shape.

  The cylindrical lens 1113 condenses the light output from the light source unit 1100 in the vicinity of the deflection reflection surface of the polygon mirror 1114 via the mirror 1117.

  The polygon mirror 1114 is made of a regular hexagonal columnar member having a low height, and six deflection reflection surfaces are formed on the side surface. Then, it is rotated at a constant angular velocity in the direction indicated by the arrow Y by a rotation mechanism (not shown).

  Accordingly, the light emitted from the light source unit 1100 and condensed near the deflection reflection surface of the polygon mirror 1114 by the cylindrical lens 1113 is deflected at a constant angular velocity by the rotation of the polygon mirror 1114.

  The fθ lens 1115 has an image height proportional to the incident angle of light from the polygon mirror 1114, and moves the image surface of light deflected by the polygon mirror 1114 at a constant angular velocity with constant speed in the main scanning direction. The toroidal lens 1116 forms an image of the light from the fθ lens 1115 on the surface of the photosensitive drum 1030 via the mirror 1118.

  The toroidal lens 1116 is disposed on the optical path of the light beam through the fθ lens 1115. Then, the light beam that has passed through the toroidal lens 1116 is irradiated onto the surface of the photosensitive drum 1030 to form a light spot. This light spot moves in the longitudinal direction of the photosensitive drum 1030 as the polygon mirror 1114 rotates. That is, the photoconductor drum 1030 is scanned. The moving direction of the light spot at this time is the “main scanning direction”. The rotation direction of the photosensitive drum 1030 is the “sub-scanning direction”.

  The optical system arranged on the optical path between the polygon mirror 1114 and the photosensitive drum 1030 is also called a scanning optical system. In this embodiment, the scanning optical system includes an fθ lens 1115 and a toroidal lens 1116. Note that at least one folding mirror may be disposed on at least one of the optical path between the fθ lens 1115 and the toroidal lens 1116 and on the optical path between the toroidal lens 1116 and the photosensitive drum 1030.

  Since the laser printer 1000 according to the present embodiment uses any one of the surface emitting laser units according to the first to fourth embodiments, the laser printer 1000 can perform stable writing with light. High-definition and high-quality image formation can be performed.

  In the description of the present embodiment, the case of the laser printer 1000 as the image forming apparatus has been described. However, the present invention is not limited to this.

  For example, an image forming apparatus 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.

[Sixth Embodiment]
Next, a sixth embodiment will be described. The sixth embodiment is a color printer 2000 including a plurality of photosensitive drums.

  Based on FIG. 20, the color printer 2000 in this Embodiment is demonstrated. The color printer 2000 in the present embodiment is a tandem multicolor printer that forms a full-color image by superimposing four colors (black, cyan, magenta, and yellow). “Charging device K2, developing device K4, cleaning unit K5, and transfer device K6”, “photosensitive drum C1, charging device C2, developing device C4, cleaning unit C5, and transfer device C6” for cyan, and magenta “Photosensitive drum M1, charging device M2, developing device M4, cleaning unit M5, and transfer device M6” and yellow “photosensitive drum Y1, charging device Y2, developing device Y4, cleaning unit Y5, and transfer device Y6” ”, Optical scanning device 2010, transfer belt 2080, fixing unit 2030, and the like. It is equipped with a.

  Each photosensitive drum rotates in the direction of the arrow shown in FIG. 20, and a charging device, a developing device, a transfer device, and a cleaning unit are arranged around each photosensitive drum in the order of rotation. Each charging device uniformly charges the surface of the corresponding photosensitive drum. The surface of each photoconductive drum charged by the charging device is irradiated with light by the optical scanning device 2010, and a latent image is formed on each photoconductive drum. Then, a toner image is formed on the surface of each photosensitive drum by a corresponding developing device. Further, the toner image of each color is transferred onto the recording paper on the transfer belt 2080 by the corresponding transfer device, and finally the image is fixed on the recording paper by the fixing unit 2030.

  The optical scanning device 2010 has a light source unit including any one of the surface emitting laser units in the first to fourth embodiments for each color, and the optical scanning described in the fifth embodiment. An effect similar to that of the device 1010 can be obtained. In addition, since the color printer 2000 includes the optical scanning device 2010, it is possible to obtain the same effect as the laser printer 1000 in the fifth embodiment.

  By the way, in the color printer 2000, color misregistration may occur due to manufacturing error or position error of each component. Even in such a case, each light source of the optical scanning device 2010 is formed by the light source unit including the surface emitting laser unit according to any one of the first to fourth embodiments. By selecting, color misregistration can be reduced.

  Therefore, since the color printer 2000 according to the present embodiment uses any one of the surface emitting laser units according to the first to fourth embodiments, a high-quality image can be formed.

  As mentioned above, although the form which concerns on implementation of this invention was demonstrated, the said content does not limit the content of invention.

DESCRIPTION OF SYMBOLS 10 Surface emitting laser element 11 Surface emitting laser 11a, 11b, 11c, 11d, 11e, 11f Surface emitting laser 12a, 12b, 12c Group of surface emitting laser 20 Light receiving element 21 Opening part 30 Package part 31 Wiring 32 Bonding wire 33 Bonding wire 40 Cap unit 41 Transparent member 50 Write control unit 1000 Laser printer (image forming apparatus)
1010 Optical scanning device 2000 Color printer (image forming apparatus)

JP-A-8-330661 JP 2007-298563 A

Claims (10)

A surface emitting laser element in which a plurality of surface emitting lasers are formed;
A light receiving element that receives part of the laser light emitted from the surface emitting laser;
A package portion and a cap portion covering the surface emitting laser element and the light receiving element;
A control unit for controlling the surface emitting laser element based on the output obtained by the light receiving element;
Have
The cap portion is provided with a transparent member that transmits the laser light emitted from the surface emitting laser,
A part of the laser light emitted from the surface emitting laser is reflected by the transparent member and enters the light receiving element,
The surface-emitting laser element is provided with a plurality of groups of surface-emitting lasers including a part of the plurality of surface-emitting lasers,
The control unit emits the surface emitting laser, and selects any one group of surface emitting lasers from a group of surface emitting lasers based on an output monitor signal detected by the light receiving element. A surface emitting laser unit.   2. The surface emitting laser unit according to claim 1, wherein the selected group of surface emitting lasers includes a surface emitting laser having the highest amount of light detected by the light receiving element. A surface emitting laser element in which a plurality of surface emitting lasers are formed;
A light receiving element that receives part of the laser light emitted from the surface emitting laser;
A package portion and a cap portion covering the surface emitting laser element and the light receiving element;
A control unit for controlling the surface emitting laser element based on the output obtained by the light receiving element;
Have
The cap portion is provided with a transparent member that transmits the laser light emitted from the surface emitting laser,
A part of the laser light emitted from the surface emitting laser is reflected by the transparent member and enters the light receiving element,
The light receiving element is divided into a plurality of regions,
The control unit emits the surface emitting laser and selects a region of the light receiving element corresponding to the surface emitting laser based on an output monitor signal detected by a plurality of regions in the light receiving element. Surface emitting laser unit.   4. The surface emitting laser unit according to claim 3, wherein the selected region of the light receiving element is one region for one surface emitting laser.   4. The surface emitting laser unit according to claim 3, wherein the selected region of the light receiving element is one or more regions for one surface emitting laser. The laser light emitted from the surface emitting laser and transmitted through the transparent member passes through the aperture,
The aperture has an opening formed long in one direction,
6. The surface emitting laser according to claim 3, wherein a longitudinal direction of the region divided in the light receiving element and a longitudinal direction of the opening in the aperture are the same direction. unit.   7. The surface emitting laser according to claim 1, wherein a two-dimensional surface emitting laser array is formed in the surface emitting laser element by a plurality of the surface emitting lasers. unit. An optical scanning device that scans a surface to be scanned with light,
A light source comprising the surface emitting laser unit according to claim 1;
A light deflector for deflecting light from the light source;
A scanning optical system for condensing the light deflected by the light deflection unit on the surface to be scanned;
An optical scanning device comprising: An image carrier;
The optical scanning device according to claim 8, wherein the image carrier is scanned with light modulated according to image information;
An image forming apparatus comprising:   The image forming apparatus according to claim 9, wherein there are a plurality of the image carriers, and the image information is multicolor color information.

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