JP2009224728A - Light source apparatus, optical scanning apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent temperature in a light source apparatus from being raised to stably emit laser light. <P>SOLUTION: Temperatures generated in each of VCSELs are collected to be discharged to an outside air through: a ground pad 10c formed on a case 10b; a first and second lands 76c and 76d formed on a substrate 76; a biasing member 78 where a pressing part 78c comes into contact with the second land 76d; and heat-receiving parts 81a formed on a heat pipe 81. Moreover, heats conducted from a circuit and electric element provided on the substrate 76 to a light source 10 through the substrate 76 is collected to be discharged to the outside air through: the first and second lands 76c and 76d formed on the substrate 76; the biasing member 78 where the pressing part 78c comes into contact with the second land 76d; and the heat-receiving parts 81a formed on the heat pipe 81. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light source device, an optical scanning device, and an image forming apparatus. More specifically, the present invention relates to a light source device that emits laser light, an optical scanning device that scans a surface to be scanned, and an image forming apparatus that forms an image on a recording medium. About.

  As an image forming apparatus that forms an image using laser light, for example, the surface of a rotating photosensitive drum is scanned with laser light to form a latent image on the surface of the photosensitive drum, and the latent image is visualized. An image forming apparatus that forms an image by fixing the obtained toner image on a sheet as a recording medium is known.

  In recent years, this type of image forming apparatus is often used for simple printing as an on-demand printing system, and there is an increasing demand for higher image density and faster image output. Therefore, recently, a plurality of light emitting areas are monolithically arranged two-dimensionally, for example, provided with a light source such as a vertical cavity surface emitting laser (VCSEL), and a plurality of laser beams emitted from the light source. Thus, an image forming apparatus capable of simultaneously scanning a plurality of scanning lines on the surface to be scanned has been proposed.

  In the surface light emitting element, the number of wirings for a plurality of light emitting regions is enormous, and therefore, the light emitting element is usually mounted on a circuit board in a state of being accommodated in a ceramic package or the like (see, for example, Patent Document 1) . A driver IC and a power source for driving the light emitting element are also mounted on the circuit board.

JP 2007-79295 A

  When the driver IC and the power source are mounted apart from the light emitting element, there is a disadvantage that the wiring length between the driver IC and the light emitting element becomes long and the response speed of the light emitting element is delayed. For this reason, it is necessary to mount the driver IC and the light emitting element close to each other.

  However, when the driver IC or the like and the light emitting element are arranged close to each other, heat generated from the driver IC or the like is transmitted to the light emitting element through the circuit board, and the temperature of the light emitting element is increased. For example, the power required for emitting one light emitting area by the driver IC is only about 0.2 mW, but for example, the power required for emitting 32 light emitting areas is 6 mW or more. For this reason, the temperature rise of the light emitting element due to the heat transmitted from the driver IC is expected to be approximately 15 ° C. Further, in consideration of self-heating of the light emitting element itself, the temperature rise is expected to exceed 15 ° C.

  In general, when the temperature of the active layer of the light emitting device rises by 10 ° C., the lifetime of the light emitting device is halved. To extend the life of the light emitting device, the amount of heat transmitted to the light emitting device is suppressed as much as possible and the light emission is performed. It is necessary to efficiently dissipate the heat generated in the element and minimize the temperature rise of the active layer.

  As a configuration of the light source unit capable of suppressing the temperature rise of the semiconductor laser, for example, a light source unit using a Peltier element is disclosed as disclosed in JP-A-60-172017. It is difficult to directly ground the Peltier device to the package that houses the light emitting type light emitting device.

  The present invention has been made under such circumstances, and a first object of the present invention is to provide a light source device capable of suppressing the temperature rise of the light source and stably emitting laser light.

  Also. A second object of the present invention is to provide an optical scanning device capable of stably and accurately scanning a surface to be scanned.

  A third object of the present invention is to provide an image forming apparatus capable of stably and accurately forming a high-definition image.

  According to a first aspect of the present invention, there is provided a light source device that emits laser light, wherein a light source in which a plurality of light emitting regions that emit laser light are two-dimensionally formed; and a lead terminal wired to the light source; A light source device comprising: a package that accommodates the light source; a substrate on which a land in contact with the package is formed and on which the package is mounted; and a heat dissipation mechanism that dissipates heat from the land.

  According to this, the heat generated from the light source is transmitted to the land formed on the substrate. The heat transmitted to the land is radiated by the heat dissipation mechanism. The heat transmitted to the light source through the substrate is stored in a land formed on the substrate and then radiated to the outside by the heat dissipation mechanism. Therefore, it is possible to suppress the temperature rise of the light source and emit a stable laser beam.

  According to a second aspect of the present invention, there is provided an optical scanning device that scans a surface to be scanned in the main scanning direction using laser light, the light source device of the present invention; and laser light emitted from the light source device. A scanning optical system that deflects and scans in the main scanning direction.

  According to this, since the laser light is stably emitted from the light source, it becomes possible to scan the surface to be scanned stably and accurately.

  According to a third aspect of the present invention, there is provided an image forming apparatus for forming an image by fixing a toner image formed on the basis of a latent image obtained from information relating to an image to a recording medium. An optical scanning device of the invention; a photosensitive member on which a latent image is formed by the optical scanning device; a developing unit that visualizes a latent image formed on a surface to be scanned of the photosensitive member; and a visible image formed by the developing unit An image forming apparatus comprising: transfer means for fixing the converted toner image to the recording medium.

  According to this, a final image is formed based on the latent image formed based on the stably emitted laser beam. Therefore, it is possible to form an image on the recording medium with high accuracy.

  According to a fourth aspect of the present invention, a toner image formed based on a latent image for each color obtained from information on a multicolor image is superimposed and fixed on a recording medium, whereby a multicolor image is obtained. An image forming apparatus to be formed, the optical scanning device of the present invention; a plurality of photoreceptors on which latent images corresponding to respective colors are formed by the optical scanning device; and a scanning surface of each of the plurality of photoreceptors An image forming apparatus comprising: a developing unit that visualizes the formed latent image; and a transfer unit that superimposes and fixes the toner images for each color visualized by the developing unit on the recording medium.

  According to this, a final image is formed based on the latent image formed based on the stably emitted laser beam. Therefore, it is possible to form an image on the recording medium with high accuracy.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus 500 according to the present embodiment.

  The image forming apparatus 500 is, for example, a tandem color printer that prints a multicolor image by superimposing and transferring black, yellow, magenta, and cyan toner images on plain paper (paper). As shown in FIG. 1, the image forming apparatus 500 includes an optical scanning device 100, four photosensitive drums 30A, 30B, 30C, and 30D, a transfer belt 40, a paper feed tray 60, a paper feed roller 54, a first resist. A roller 56, a second registration roller 52, a fixing roller 50, a paper discharge roller 58, a control device (not shown) that comprehensively controls each of the above parts, and a substantially rectangular parallelepiped housing 501 that accommodates the above components. .

  The housing 501 is formed with a paper discharge tray 501a on which the printed paper is discharged on the upper surface, and the optical scanning device 100 is disposed below the paper discharge tray 501a.

  The optical scanning device 100 scans the photosensitive drum 30A with a laser beam of a black image component modulated based on image information supplied from a host device (such as a personal computer), and cyan the photosensitive drum 30B. The image component laser beam is scanned, the photosensitive drum 30C is scanned with the magenta image component laser beam, and the photosensitive drum 30D is scanned with the yellow image component laser beam. The configuration of the optical scanning device 100 will be described later.

  The four photosensitive drums 30A, 30B, 30C, and 30D are cylindrical members each having a photosensitive layer having a property that becomes electrically conductive when irradiated with laser light. Below the scanning device 100 are arranged at equal intervals along the X-axis direction.

  The photosensitive drum 30A is disposed at the −X side end in the housing 501 with the Y-axis direction as the longitudinal direction, and is rotated clockwise in FIG. 1 (the direction indicated by the arrow in FIG. 1) by a rotation mechanism (not shown). It is like that. In the vicinity thereof, a charging charger 32A is arranged at the 12 o'clock (upper) position in FIG. 1, a toner cartridge 33A is arranged at the 2 o'clock position, and a cleaning case 31A is arranged at the 10 o'clock position. .

  The charging charger 32A is arranged with a predetermined clearance with respect to the surface of the photosensitive drum 30A with the longitudinal direction as the Y-axis direction, and charges the surface of the photosensitive drum 30A with a predetermined voltage.

  The toner cartridge 33A includes a cartridge main body filled with black image component toner, a developing roller charged with a voltage having a polarity opposite to that of the photosensitive drum 30A, and the toner filled in the cartridge main body is passed through the developing roller. The toner is supplied to the surface of the photosensitive drum 30A.

  The cleaning case 31A includes a rectangular cleaning blade whose longitudinal direction is the Y-axis direction, and is arranged so that one end of the cleaning blade is in contact with the surface of the photosensitive drum 30A. The toner adsorbed on the surface of the photosensitive drum 30A is peeled off by the cleaning blade as the photosensitive drum 30A rotates, and is collected in the cleaning case 31A.

  The photosensitive drums 30B, 30C, and 30D have the same configuration as the photosensitive drum 30A, and are sequentially arranged at a predetermined interval on the + X side of the photosensitive drum 30A. Around the periphery, charging chargers 32B, 32C, and 32D, toner cartridges 33B, 33C, and 33D, and cleaning cases 31B, 31C, and 31D are arranged in the same positional relationship as the above-described photosensitive drum 30A.

  The charging chargers 32B to 32D are configured similarly to the charging charger 32A described above, and charge the surfaces of the photosensitive drums 30B to 30D with a predetermined voltage.

  Each of the toner cartridges 33B to 33D includes a cartridge main body filled with cyan, magenta, and yellow image component toners and a developing roller that is charged with a voltage having a polarity opposite to that of the photosensitive drums 30B to 30D. The toner thus supplied is supplied to the surfaces of the photosensitive drums 30B to 30D via the developing roller.

  The cleaning cases 31B to 31D are configured in the same manner as the cleaning case 31A and function in the same manner.

  Hereinafter, the photosensitive drum 30A, the charging charger 32A, the toner cartridge 33A, and the cleaning case 31A are collectively referred to as a first station, and the photosensitive drum 30B, the charging charger 32B, the toner cartridge 33B, and the cleaning case 31B are collectively referred to as a second station, The photosensitive drum 30C, the charging charger 32C, the toner cartridge 33C, and the cleaning case 31C are collectively referred to as a third station, and the photosensitive drum 30D, the charging charger 32D, the toner cartridge 33D, and the cleaning case 31D are collectively referred to as a fourth station. .

  The transfer belt 40 is an endless annular member, and is driven by driven rollers 40a and 40c disposed below the photosensitive drums 30A and 30D, and a driving roller 40b disposed at a position slightly lower than the driven rollers 40a and 40c, respectively. The upper end surface is wound so as to be in contact with the lower end surfaces of the photosensitive drums 30A, 30B, 30C, and 30D. The drive roller 40b rotates counterclockwise (in the direction indicated by the arrow in FIG. 1) by rotating counterclockwise in FIG. A transfer charger 48 to which a voltage having a polarity opposite to that of the above-described charging chargers 32A, 32B, 32C, and 32D is applied is disposed near the + X side end of the transfer belt 40.

  The paper feed tray 60 is disposed below the transfer belt 40. The paper feed tray 60 is a substantially rectangular parallelepiped tray, and a plurality of sheets 61 to be printed are stacked and stored therein. A rectangular paper feed port is formed near the + X side end of the upper surface of the paper feed tray 60.

  The paper feed roller 54 takes out the paper 61 one by one from the paper feed tray 60 and leads it to a gap formed by the transfer belt 40 and the transfer charger 48 via a first registration roller 56 composed of a pair of rotating rollers. To do.

  The fixing roller 50 is composed of a pair of rotating rollers, overheats and pressurizes the paper 61, and guides it to the paper discharge roller 58 via the second registration roller 52.

  The paper discharge roller 58 includes a pair of rotating rollers, and sequentially stacks the derived paper 61 on the paper discharge tray 501a.

  Next, the configuration of the optical scanning device 100 will be described. 2 is a perspective view showing the optical scanning device 100, and FIG. 3 is a view of the optical scanning device 100 as seen from the side. 2 and 3, the optical scanning device 100 includes a polygon mirror 104, an fθ lens 105, a reflection mirror 106B, and a reflection mirror 106A, fθ that are sequentially arranged in the −X direction of the polygon mirror 104. Reflective mirror 108B disposed below lens 105, toroidal lens 107B sequentially disposed in the -X direction of reflective mirror 108B, reflective mirror 108A, toroidal lens 107A, and fθ disposed in the + X direction of polygon mirror 104 Scanning including a lens 305, a reflection mirror 306C and a reflection mirror 306D, a reflection mirror 308C disposed below the fθ lens 305, a toroidal lens 307C, a reflection mirror 308D, and a toroidal lens 307D sequentially disposed in the + X direction of the reflection mirror 308C With optics Two incident optical systems: an incident optical system 200A that makes laser light that scans the photosensitive drums 30A and 30B enter the polygon mirror 104, and an incident optical system 200B that makes the laser light that scans the photosensitive drums 30C and 30D enter the polygon mirror 104. And.

  The incident optical systems 200A and 200B are optical systems that allow laser light to be incident on the deflection surface of the polygon mirror 104 from a direction that forms 120 degrees or 60 degrees with respect to the X axis, and are representative of the incident optical system 200B in FIG. As shown, the light source device 70, a light beam splitting prism 202, a set of liquid crystal elements 203A and 203B, and a set of cylinder lenses arranged in order along the path of the laser light emitted from the light source device 70. 204A and 204B are provided. Here, for convenience of explanation, an xyz coordinate system defined by rotating an XY coordinate by an angle of 30 degrees around the Z axis is defined, and the explanation using this coordinate system will be given as appropriate.

  FIG. 4 is a perspective view showing the light source device 70. As shown in FIG. 4, the light source device 70 includes a substrate 76, a first holder 74, a second holder 72 that holds the coupling lens 11, a heat dissipation unit 80, and the like.

  5 and 6 are exploded perspective views of the light source device 70. FIG. 5 and 6, the substrate 76 is a substrate whose longitudinal direction is the x-axis direction. For example, the light source 10 and the light receiving element 18 are mounted on the surface on the −y side. A driving IC 77 for driving the light source 10 and a monitor circuit (not shown) for monitoring a signal output from the light receiving element 18 are formed on the surface on the + y side. The substrate 76 is formed with three round holes 76 a and three slits 76 b so as to surround the light source 10.

  FIGS. 7A and 7B are perspective views of the substrate 76. As can be seen from the overall view of FIG. 7A and FIG. 7B, in the present embodiment, the portion on the −y side surface of the substrate 76 where the light source 10 is mounted has a circular first. One land 76c is formed, and a plurality of connection patterns 76e are arranged around the first land 76c in the x-axis direction and the z-axis direction. A square second land 76d is formed in a portion of the substrate 76 on the + y side opposite to the portion where the first land 76c is formed. Each of the first land 76c and the second land 76d is formed by bonding, for example, a copper foil, and is electrically connected through a through hole (not shown) provided in the substrate 76.

  FIG. 8A and FIG. 8B are perspective views of the light source 10. 8A and 8B, the light source 10 is formed in a square case 10b, a square plate-like transparent glass 10e fixed to the case 10b, and the case 10b. It has the light emitting element 10a arrange | positioned.

  The light emitting element 10a is an element having a light emitting surface on which a plurality of VCSELs are two-dimensionally arranged. As shown in FIG. 9, 32 VCSELs that emit divergent light in the −y direction are parallel to a straight line L1 that forms an angle θ1 with the x axis on the light emitting surface (−y side surface) of the light emitting element 10a. Are arranged in a matrix of 4 rows and 8 columns, with the direction being the row direction and the direction parallel to the z-axis being the column direction. In the present embodiment, as an example, the distance Dz in the sub-scanning direction of the VCSEL is 18.4 μm, the distance Dx in the main scanning direction is 30 μm, and the adjacent light emitting sources in the z-axis direction (sub-scanning direction) of each VCSEL The distance dz is 2.3 μm (= Dz / 8). And the light emitting element 10a is arrange | positioned in the center of case 10b in the state in which the light emission surface became parallel to the surface by the side of -y of case 10b.

  In the light source 70, each VCSEL formed in the light emitting element 10a is electrically connected to a corresponding lead terminal 10d provided around the case 10b by, for example, solder. The drive signal is supplied from the lead terminal 10d so that the laser beam is emitted in the -y direction. Further, as shown in FIG. 8B, a circular grounding pad 10c is formed on the surface of the case 10b on the + y side by plating. In the present embodiment, the ground pad 10c is connected to the + y side surface of the light emitting element 10a by, for example, a VIA hole.

  As can be seen from the light source 10 configured as described above, referring to FIG. 7A, the ground pad 10c formed on the case 10b has a first land 76c formed on the -y side surface of the substrate 76. The lead terminals 10d formed on the case 10b are mounted on the substrate 76 in a state of being electrically connected to the connection patterns 76e formed around the first land 76c.

  As shown in FIG. 5, the light receiving element 18 is disposed on the + x side of the light source 10 and outputs a signal (photoelectric conversion signal) corresponding to the intensity of the incident laser light.

  5 and 6, the first holder 74 is a box-shaped member that is open on the −y side, and the light guide optical system 20 is accommodated therein, and + y On the side surface, rectangular recesses 74b and 74c into which the light source 10 and the light receiving element 18 mounted on the substrate 76 are fitted, and the three round holes 76a of the substrate 76 are inserted so as to surround the recesses 74b. A cylindrical portion 74a is formed. A circular opening communicating with the inside of the first holder 74 is formed on the bottom wall surface of the recesses 74b and 74c.

  As described above with reference to FIG. 6, the light source 10 and the light receiving element 18 mounted on the substrate 76 are fitted in the recesses 74 b and 74 c formed in the first holder 74. In combination, the three cylindrical portions 74a formed in the first holder 74 are inserted into the three round holes 76a formed in the substrate 76, and the cylindrical portion 74a of the first holder 74 is substantially combined with the cylindrical portion 74a. The relative positional relationship is defined by attaching the triangular biasing member 78.

  The biasing member 78 is formed, for example, by processing a plate-like member having elasticity into a sheet metal, and includes three anchor portions 78b that can be inserted into the three slits 76b formed in the substrate 76, and the −y direction. A pressing portion 78c for applying an elastic force is provided. The urging member 78 is configured so that the screws 79 are inserted into the first holder through the round holes 78 a formed in the corner portions of the urging member 78 in a state where the anchor portions 78 b are respectively inserted into the slits 76 b of the substrate 76. It is fixed to the first holder 74 by being screwed into the cylindrical portion 74 a of 74. As a result, the substrate 76 is urged in the direction approaching the first holder 74 by the pressing portion 78c of the urging member 78, as shown in FIG. The surface on the −y side of the light receiving element 18 is in pressure contact with the bottom wall surface of the recesses 74 b and 74 c formed in the first holder 74.

  As shown in FIG. 5, the second holder 72 is formed so as to surround the circular opening 72 b on the plate-like main body portion formed with a circular opening 72 b in the center and on the −y side surface of the main body portion. It has three portions: an annular convex portion 72a and a lens support portion 72c extending in the −y direction from below the annular convex portion 72a. A groove having a V-shaped cross section is formed along the y-axis on the upper surface of the lens support portion 72c, and the position of the coupling lens 11 in the x-axis direction and the z-axis direction is defined by the groove. Held in a state.

  The coupling lens 11 is a lens having a refractive index of about 1.5, and couples the laser light emitted from the light source 10.

  As for the 2nd holder 72 comprised as mentioned above, the surface at the side of + y is fixed to the -y side end of the 1st holder 74 with a screw etc., for example.

  As shown in FIG. 10, the light guide optical system 20 includes a branch optical element 21, a condensing lens 22, and a reflection mirror 23 housed in a first holder 74.

  The branch optical element 21 is a plate-like member having a rectangular opening formed in the center, and a reflection surface for reflecting laser light is formed on the surface on the light source 10 side. The branch optical element 21 is held in a state inclined by 45 degrees with respect to the y-axis, and a part of the laser light incident from the + y side passes through the opening and the rest is reflected in the + x direction.

  The condensing lens 22 is a lens having positive power, and condenses the laser light reflected in the + x direction by the branching optical element 21 onto the light receiving surface of the light receiving element 18 via the reflection mirror 23.

  FIG. 11 is a perspective view showing the heat dissipation unit 80. As shown in FIG. 11, the heat radiating unit 80 is disposed on the cooling fan 83 disposed in the center of the upper surface of the rectangular plate-like base 84 whose longitudinal direction is the x-axis direction, on the −x side and the + x side of the cooling fan 83. There is a set of heat dissipating fins 82A and 82B arranged, and a heat pipe 81 filled with hydraulic fluid and having both ends connected to the heat dissipating fins 82A and 82B, respectively.

  In the heat radiating unit 80, when a bent portion of the heat pipe 81 (hereinafter referred to as a heat receiving portion 81a) receives heat, the heat is carried to the heat radiating fins 82A and 82B by the working fluid of the heat pipe 81. Then, cooling air is supplied to each of the radiation fins 82A and 82B by the cooling fan 83 to be discharged into the outside air.

  In the light source device 70 according to the present embodiment, as can be seen from a comprehensive view of FIGS. 6 and 10 as an example, the + y of the urging member 78 in a state in which the heat receiving portion 81a of the heat radiating unit 80 surrounds the light source 10. Welded to the side surface. Accordingly, the heat generated from the light emitting element 10a is in contact with the second land 76d by the ground pad 10c formed on the case 10b, the first land 76c and the second land 76d formed on the substrate 76, and the pressing portion 78c. Heat is collected through the urging member 78 and the heat receiving portion 81a formed in the heat pipe 81, and is radiated to the outside air. Similarly, the heat transmitted to the light source 10 through the substrate 76 is collected through the first land 76c, the second land 76d, the urging member 78, and the heat receiving portion 81a and is radiated to the outside air. ing.

  In the light source device 70 configured as described above, as an example, as illustrated in FIG. 12, the annular protrusion 72 a of the second holder 72 is fitted into an opening formed in the support member 101 such as an optical housing. Thus, the coupling lens 11 is supported so as to be rotatable around the optical axis. Thereby, by rotating the light source device 70, it is possible to adjust the pitch of the laser light condensed on the photosensitive drum in the sub-scanning direction to a predetermined pitch.

  Returning to FIG. 2, the light beam splitting prism 202 splits the laser light that has passed through the opening 21a of the branching optical element 21 into two laser lights that are separated by a predetermined distance (for example, 6 mm) in the vertical direction (sub-scanning direction). .

  The liquid crystal elements 203A and 203B are arranged adjacent to each other in the vertical direction so as to correspond to each of the laser beams divided into two by the light beam splitting prism 202, and the laser beams are subdivided according to a voltage signal from a control device (not shown). Deflection in the scanning direction.

  The cylinder lenses 204 </ b> A and 204 </ b> B are arranged adjacent to each other in the vertical direction corresponding to each of the laser beams divided into two by the light beam splitting prism 202, and collect the incident laser beams on the polygon mirror 104. The cylinder lenses 204A and 204B have a positive curvature at least in the sub-scanning direction, and the deflection points on the polygon mirror 104 and the surfaces of the photosensitive drums 30A to 30D are sub-driven by toroidal lenses 107A to 107D described later. A surface tilt correction optical system having a conjugate relationship in the scanning direction is formed.

  The polygon mirror 104 is composed of a pair of regular quadrangular prism-shaped members having side surfaces formed with laser beam deflection surfaces, and the members are arranged adjacent to each other in the vertical direction with a phase difference of 45 degrees from each other. ing. Then, it is rotated at a constant angular velocity in the direction of the arrow shown in FIG. 2 by a rotation mechanism (not shown). As a result, the two laser beams divided into two by the light beam splitting prism 202 of the incident optical system 200A or the incident optical system 200B and condensed on the deflecting surface of the polygon mirror 104 are deflected on different deflecting surfaces. By being deflected, they are incident on the photosensitive drum alternately.

  The fθ lenses 105 and 305 have an image height proportional to the incident angle of the laser beam, and move the image plane of the laser beam deflected at a constant angular velocity by the polygon mirror 104 at a constant speed with respect to the Y axis.

  The reflection mirrors 106A, 106B, 306C, and 306D are arranged with the longitudinal direction as the Y-axis direction, and turn back the laser light that has passed through the fθ lenses 105 and 305 to enter the toroidal lenses 107A, 107B, 307C, and 307D, respectively.

  The toroidal lenses 107A, 107B, 307C, and 307D are arranged with the longitudinal direction as the Y-axis direction, and the laser beams folded by the reflection mirrors 106A, 106B, 306C, and 306D are reflected with the Y-axis direction as the longitudinal direction. Images are formed on the surfaces of the photosensitive drums 30A, 30B, 30C, and 30D via the mirrors 108A, 108B, 308C, and 308D, respectively.

  Light detection sensors 141A and 141B are arranged near the + Y side (laser light incident side) end portions of the toroidal lenses 107A and 107B, respectively, and near the −Y side (laser light incident side) end portions of the toroidal lenses 307C and 307D. Are respectively provided with photodetection sensors 141C and 141D. Further, photodetection sensors 142A and 142B are arranged near the −Y side end portions of the toroidal lenses 107A and 107B, respectively, and photodetection sensors 142C and 142D are arranged near the + Y side end portions of the toroidal lenses 307C and 307D, respectively. ing. For example, the light detection sensors 141A to 141D and 142A to 142D output a signal that is turned on while the laser light is incident and turned off otherwise.

  Next, the operation of the image forming apparatus 500 including the optical scanning device 100 configured as described above will be described. When image information is supplied from a host device or the like, laser light is emitted from the light source devices 70 of the incident optical system 200A and the incident optical system 200B. The light beam emitted from the light source device 70 of the incident optical system 200A is divided into two in the vertical direction by the light beam splitting prism 202. Each of the divided laser beams is subjected to position correction in the sub-scanning direction by passing through the liquid crystal elements 203A and 203B, and then condensed on the deflection surface of the polygon mirror 104 by the cylinder lenses 204A and 204B. Then, the laser beam deflected by the polygon mirror 104 enters the fθ lens 105.

  The upper laser beam incident on the fθ lens 105 is reflected by the reflection mirror 106B and enters the toroidal lens 107B. Then, the light is condensed on the surface of the photosensitive drum 30B by the toroidal lens 107B via the reflection mirror 108B. The lower laser light incident on the fθ lens 105 is reflected by the reflection mirror 106A and enters the toroidal lens 107A. Then, the light is condensed on the surface of the photosensitive drum 30A by the toroidal lens 107A via the reflection mirror 108A. The polygon mirror 104 has a phase difference of 45 degrees between the upper and lower deflection surfaces as described above. Therefore, the scanning of the photosensitive drum 30B by the upper laser beam and the scanning of the photosensitive drum 30A by the lower laser beam are performed in the −Y direction based on the signals output from the light detection sensors 141A, 141B, 142A, and 142B, respectively. Will be performed alternately.

  On the other hand, the laser light emitted from the light source device 70 of the incident optical system 200B is divided into two in the vertical direction by the light beam splitting prism 202. Each of the divided laser beams passes through the liquid crystal elements 203A and 203B, and is subjected to position correction in the sub-scanning direction, and then condensed on the deflection surface of the polygon mirror 104 from the cylinder lenses 204A and 204B. The laser beam deflected by the polygon mirror 104 enters the fθ lens 305.

  The upper laser light incident on the fθ lens 305 is reflected by the reflection mirror 306C and enters the toroidal lens 307C. Then, the light is condensed on the surface of the photosensitive drum 30C by the toroidal lens 307C via the reflection mirror 308C. The lower laser light incident on the fθ lens 305 is reflected by the reflection mirror 306D and incident on the toroidal lens 307D. Then, the light is condensed on the surface of the photosensitive drum 30D by the toroidal lens 307D via the reflection mirror 308D. The polygon mirror 104 has a phase difference of 45 degrees between the upper and lower deflection surfaces as described above. Therefore, the scanning of the photosensitive drum 30C by the upper laser beam and the scanning of the photosensitive drum 30D by the lower laser beam are directed in the + Y direction based on the signals output from the light detection sensors 141C, 141D, 142C, and 142D, respectively. Will be performed alternately.

  In the light source device 70, as shown in FIG. 10, the laser light emitted from the light source 10 and reflected by the reflecting surface of the branch optical element 21 is incident on the light receiving element 18 by the condenser lens 22. In the light source device 70, a signal output when the laser light enters the light receiving element 18 is constantly monitored, and the light amount control of the laser light emitted from the light source 10 is performed.

  Specifically, the laser light is received by the light receiving element 18 after the laser light is deflected by the deflection surface of the polygon mirror 104 and before reaching the writing area of the photosensitive drum. The light source device 70 detects the intensity of the laser light emitted from the light source 10 based on the photoelectric conversion signal output from the light receiving element 18 by receiving the laser light, and the intensity of the laser light emitted from the light source 10. Is set (determined) to the value of the injected power supplied to each VCSEL so that the intensity is set in advance. As a result, the laser light that has passed through the opening 21a of the branch optical element 21 enters the writing areas of the photosensitive drums 30A to 30D in a state adjusted to a preset intensity. Note that the value of the above-described injection power is once reset when scanning of the writing area is completed, and is set again before scanning of the next writing area. That is, the output adjustment of each VCSEL is performed every time the writing area is scanned.

  On the other hand, the photosensitive layer on the surface of each of the photosensitive drums 30A, 30B, 30C, and 30D is charged with a predetermined voltage by the charging chargers 32A, 32B, 32C, and 32D, so that charges are distributed at a constant charge density. . As described above, when each of the photosensitive drums 30A, 30B, 30C, and 30D is scanned, the photosensitive layer where the laser light is focused comes to have conductivity, and the potential is almost zero at that portion. Become. Accordingly, when the photosensitive drums 30A, 30B, 30C, and 30D rotating in the directions of the arrows in FIG. 1 are scanned with the laser light modulated based on the image information, the respective photosensitive drums 30A and 30B are scanned. , 30C and 30D, electrostatic latent images defined by the charge distribution are formed.

  When electrostatic latent images are formed on the surfaces of the photosensitive drums 30A, 30B, 30C, and 30D, the developing rollers of the toner cartridges 33A, 33B, 33C, and 33D shown in FIG. Toner is supplied to each surface of 30D. At this time, since the developing rollers of the toner cartridges 33A, 33B, 33C, and 33D are charged with a voltage having a polarity opposite to that of the photosensitive drums 30A, 30B, 30C, and 30D, the toner adhering to the developing rollers is exposed to the photosensitive drums 30A, 30B, It is charged with the same polarity as 30C and 30D. Therefore, the toner does not adhere to the portions of the surfaces of the photosensitive drums 30A, 30B, 30C, and 30D where the electric charges are distributed, and the toner adheres only to the scanned portions, whereby the photosensitive drums 30A, 30B, and 30C. , A toner image in which the electrostatic latent image is visualized is formed on the surface of 30D.

  As described above, the respective toner images formed at the first station, the second station, the third station, and the fourth station based on the image information are transferred while being superimposed on the surface of the transfer belt 40, It is transferred by the transfer charger 48 to the surface of the paper 61 taken out from the paper feed tray 60 and fixed by the fixing roller 50. The paper 61 on which the image is thus formed is discharged by the paper discharge roller 58 and is sequentially stacked on the paper discharge tray 501a.

  As described above, in the light source device 70 according to the present embodiment, the heat generated in each VCSEL formed in the light emitting element 10a constituting the light source 10 is formed in the ground pad 10c and the substrate 76 formed in the case 10b. The collected first land 76c and second land 76d, the biasing member 78 in which the pressing portion 78c is in contact with the second land 76d, and the heat receiving portion 81a formed in the heat pipe 81 are collected and radiated into the outside air. Is done. In addition, heat transmitted from the circuit and electric elements provided on the substrate 76 including the driving IC 77 to the light source 10 through the substrate 76 is transmitted to the first land 76c, the second land 76d, the urging member 78, and the heat receiving portion. Heat is collected via 81a and radiated to the outside air.

  Thereby, the temperature rise of the light emitting element 10a which comprises the light source 10 is suppressed, a laser beam can be stably emitted from the light source 10, and the lifetime of the light source 10 can be extended.

  Further, in the light source device 70, heat is radiated through an electric circuit such as the ground pad 10c formed on the case 10b and the first land 76c and the second land 76d formed on the substrate 76. Therefore, it is not necessary to provide a separate heat transfer path from the VCSEL, and the light source device 70 can be downsized and the device structure can be simplified.

  Further, in the light source device 70, by arbitrarily arranging the heat pipe 81, it is not necessary to dispose the radiation fins 82A and 82B in the vicinity of the light source 10, so that the degree of freedom of the device structure can be improved. .

  In this embodiment, the substrate 76 is urged to the first holder 74 by the pressing portion 78c of the urging member 78. However, the present invention is not limited to this, and for example, as shown in FIG. 13, a heat pipe having sufficient elasticity. The elastic force 81 may be applied to the substrate 76 to bias the substrate 76 to the first holder 74. According to this, since the heat pipe 81 is in direct contact with the second land 76d formed on the substrate 76, the thermal resistance is reduced, and the heat radiation efficiency can be improved.

  In this embodiment, the case where the heat pipe 81 of the heat radiating unit 80 is attached to the urging member 78 has been described. However, the present invention is not limited thereto, and the heat pipe 81 may be attached in contact with the substrate 76. As an example, as shown in FIG. 14, a groove portion 74 d in which the heat receiving portion 818 a of the heat pipe 81 is disposed is formed on the −y side surface of the first holder 74 so as to surround the concave portion 74 b. As shown in FIG. 15, a method is conceivable in which the heat receiving portion 81 a of the heat pipe 81 arranged in the groove portion 74 d is formed between the substrate 76 and the surface on the + y side of the first holder 74.

  In this case, as shown in FIG. 16, the second land 76 d that contacts the heat pipe 81 is formed on the −y side surface of the substrate 76. Thereby, by fastening the screw 79 screwed to the first holder 74, the second land 76d and the heat pipe 81 are pressure-bonded, and the thermal resistance between them is reduced. Therefore, the heat dissipation efficiency of the light source device 70 can be improved. As shown in FIG. 15, since the light source 10 is surrounded by the heat pipe 81, it is possible to efficiently dissipate heat transmitted from the mounted components on the substrate 76 to the light source 10 via the substrate 76.

  The optical scanning device 100 according to the present embodiment includes a light source 70. Therefore, the photosensitive drums 30 </ b> A to 30 </ b> D can be scanned with a laser beam that is stable over a long period of time.

  In the image forming apparatus 500 according to the present embodiment, a final image is formed based on the latent image formed by the optical scanning device 100. Accordingly, an image can be accurately formed on the paper 61 over a long period of time.

  In the above-described embodiment, the image forming apparatus 500 that forms a multicolor image including the plurality of photoconductors 30A to 30D has been described. However, the present invention is not limited to this, and the present invention may include, for example, a single photoconductor. The present invention can also be applied to an image forming apparatus that forms a monochrome image by scanning with light.

  In the above embodiment, the case where the optical scanning device 100 of the present invention is used in a printer has been described. However, the image forming apparatus other than the printer, for example, a copier, a facsimile, or a multifunction machine in which these are integrated. Is preferred.

1 is a diagram illustrating a schematic configuration of an image forming apparatus 500 according to an embodiment of the present invention. 1 is a perspective view of an optical scanning device 100. FIG. 2 is a side view of the optical scanning device 100. FIG. 3 is a perspective view of a light source device 70. FIG. FIG. 3 is a developed perspective view (No. 1) of a light source device. FIG. 6 is a developed perspective view (No. 2) of the light source device 70; 7A and 7B are perspective views of the substrate 76. FIG. FIG. 8A and FIG. 8B are perspective views of the light source 10. It is a top view of the light emitting element 10a. 3 is a cross-sectional view of a light source device 70. FIG. FIG. 6 is a perspective view of a heat dissipation unit 80. It is a figure for demonstrating the method to attach the light source device. It is a figure which shows the modification of the heat pipe. It is a figure which shows the modification of the light source device. It is sectional drawing of the light source device 70 concerning a modification. It is a perspective view of the board | substrate 76 used for the light source device 70 concerning a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Light source, 10a ... Light emitting element, 10b ... Case, 10c ... Ground pad, 10d ... Lead terminal, 10e ... Transparent glass, 11 ... Coupling lens, 18 ... Light receiving element, 20 ... Light guide optical system, 21 ... Branch optical Elements 22 ... Condensing lens 23 ... Reflecting mirror 30A-30B ... Photosensitive drum 31A-31D ... Cleaning case 32A-32D ... Charger charger 33A-33D ... Toner cartridge 40 ... Transfer belt 40a, 40c ... Drive roller, 40b ... drive roller, 48 ... transfer charger, 50 ... fixing roller, 52 ... second registration roller, 54 ... feed roller, 56 ... first registration roller, 58 ... discharge roller, 60 ... feed tray, 61 ... paper, 70 ... light source device, 72 ... second holder, 72a ... annular convex part, 72b ... circular opening, 72c ... lens support part 74 ... first holder, 74a ... cylindrical portion, 74b, 74c ... concave, 74d ... groove, 76 ... substrate, 76a ... round hole, 76b ... slit, 76c ... first land, 76d ... second land, 76e ... connection Pattern, 77 ... Drive IC, 78 ... Biasing member, 78a ... Round hole, 78b ... Anchor part, 78c ... Pressing part, 80 ... Heat radiation unit, 81 ... Heat pipe, 81a ... Heat receiving part, 82A, 82B ... Heat radiation fin, 83 ... Cooling fan, 84 ... Base, 100 ... Optical scanning device, 104 ... Polygon mirror, 105, 305 ... fθ lens, 106A, 106B, 108A, 108B, 306C, 306D, 308C, 308D ... Reflection mirror, 107A, 107B, 307C, 307D ... Toroidal lens, 141A, 141B, 141C, 141D, 142A, 142B, 142C, 142D ... light detection sensor, 202 ... light beam splitting prism, 203A, 203B ... liquid crystal element, 204A, 204B ... cylinder lens, 500 ... image forming apparatus, 501 ... housing, 501a ... discharge tray.

Claims (12)

A light source device that emits laser light,
A light source in which a plurality of light emitting regions for emitting laser light are two-dimensionally formed;
A package comprising a lead terminal wired to the light source and containing the light source;
A land in contact with the package, and a substrate on which the package is mounted;
A light source device for radiating heat from the land.   The light source device according to claim 1, further comprising a transmission member that transmits heat of the land to the heat dissipation mechanism. The land has a first land portion formed on one surface of the substrate on which the light source is mounted, and a second land portion connected to the first land portion,
The light source device according to claim 1, wherein one end portion of the transmission member is in contact with the second land portion. A coupling element for adjusting a divergence angle of laser light emitted from the light source;
The light source device according to claim 1, further comprising: a support member that supports the coupling element with respect to the substrate.   The light source device according to claim 4, wherein the transmission member has elasticity, and the one end portion is in pressure contact with the second land.   The light source device according to claim 5, wherein the transmission member positions the light source with respect to the support member by pressing the light source against the support member via the substrate.   The light source device according to claim 4, wherein the transmission member is sandwiched between the substrate and the support member.   The light source device according to claim 7, wherein the transmission member positions the light source with respect to the support member by pressing the light source against the support member.   The light source device according to claim 2, wherein one end portion of the support member is disposed so as to surround the periphery of the light source. An optical scanning device that scans a surface to be scanned in a main scanning direction using laser light,
A light source device according to any one of claims 1 to 9;
A scanning optical system that deflects and scans the laser light emitted from the light source device in the main scanning direction. An image forming apparatus that forms an image by fixing a toner image formed based on a latent image obtained from information related to an image to a recording medium,
An optical scanning device according to claim 10;
A photoreceptor on which a latent image is formed by the optical scanning device;
Developing means for visualizing a latent image formed on the surface to be scanned of the photoreceptor;
An image forming apparatus comprising: a transfer unit that fixes the toner image visualized by the developing unit to the recording medium. An image forming apparatus that forms a multicolor image by superimposing and fixing a toner image formed based on a latent image for each color obtained from information about a multicolor image on a recording medium,
An optical scanning device according to claim 10;
A plurality of photosensitive members on which latent images corresponding to the respective colors are formed by the optical scanning device;
Developing means for visualizing latent images formed on the scanned surfaces of the plurality of photoconductors;
An image forming apparatus comprising: a transfer unit configured to superimpose and fix the toner image of each color visualized by the developing unit on the recording medium.

Images