Image forming apparatus

Abstract

To provide an optical scanner that can prevent the occurrence of an image defect while preventing an increase in manufacturing cost, and an image forming apparatus including the same.SOLUTION: An optical scanner comprises a light source unit, a polygon mirror, a scanning lens, a housing, and a temperature sensor. The light source unit emits a laser beam. The polygon mirror rotates around a rotation axis extending in a vertical direction to reflect the laser beam emitted from the light source unit, and scans a peripheral surface of an image carrier with the laser beam in a main scanning direction. The scanning lens forms the laser beam reflected by the polygon mirror into an image on the peripheral surface of the image carrier. The housing accommodates the light source unit, the polygon mirror, and the scanning lens. The temperature sensor detects the temperature inside the housing. The temperature sensor detects the temperature of the image carrier.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine, a printer, a facsimile, or a combination machine thereof, that is equipped with an optical scanning device that forms a latent image on a scanned surface by exposure scanning. [Background technology]

[0002] A conventional image forming apparatus is disclosed in Patent Document 1. This image forming apparatus includes an optical scanning device. The optical scanning device includes a light source unit, a polygon mirror, a scanning lens, a housing, and a temperature sensor. The light source unit emits laser light. The polygon mirror rotates around a rotation axis extending in the vertical direction to reflect the laser light emitted from the light source unit and scan the peripheral surface of the image carrier in the main scanning direction. The scanning lens forms an image of the laser light reflected by the polygon mirror on the peripheral surface of the image carrier. The housing accommodates the light source unit, the polygon mirror, and the scanning lens. The temperature sensor detects the temperature inside the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-194613 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional image forming apparatus described above, there is a problem that a rise in temperature of the developing device causes image defects in the toner image formed on the image carrier.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of suppressing the occurrence of image defects while suppressing an increase in manufacturing costs. [Means for solving the problem]

[0006] In order to achieve the above object, a first configuration of the present invention is an image forming apparatus including an optical scanning device, an image carrier, a charging device, a developing device, and a control unit. The optical scanning device includes a light source unit, a polygon mirror, a scanning lens, a housing, and a temperature sensor. The light source unit emits a laser beam. The polygon mirror rotates around a rotation axis extending in the vertical direction to reflect the laser beam emitted from the light source unit and scans the peripheral surface of the image carrier in the main scanning direction. The scanning lens forms an image of the laser beam reflected by the polygon mirror on the peripheral surface of the image carrier. The housing accommodates the light source unit, the polygon mirror, and the scanning lens. The temperature sensor detects the temperature inside the housing. One or more image carriers are provided with a photosensitive layer formed on the surface. The charging device charges the image carrier to a predetermined surface potential. The developing device is disposed opposite the image carrier, has a developer carrier that carries a developer, and forms a toner image by applying a predetermined development voltage to the developer carrier to cause toner to adhere to an electrostatic latent image formed on the image carrier. The control unit controls the optical scanning device and the developing device. The temperature sensor detects the temperature of the developing device. The control unit controls the optical scanning device based on the temperature inside the housing detected by the temperature sensor, and also controls the developing device based on the temperature of the developing device detected by the temperature sensor. Effect of the Invention

[0007] According to the first aspect of the present invention, it is possible to provide an image forming apparatus capable of suppressing the occurrence of image defects while suppressing an increase in manufacturing costs. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus 100 equipped with an optical scanning device 5 according to the present invention. [Diagram 2] FIG. 1 is a perspective view of an optical scanning device 5 according to an embodiment of the present invention. [Diagram 3] FIG. 1 is a perspective view of an optical scanning device 5 according to an embodiment of the present invention. [Figure 4] Cross section along the line AA in Figure 2 [Diagram 5] FIG. 1 is an explanatory diagram showing an enlarged view of the circuit board 90 and its surroundings in the optical scanning device 5 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [1. Configuration of image forming apparatus 100] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus 100 in which an optical scanning device 5 of the present invention is mounted. For convenience of explanation, the vertical direction in an installation state (as shown in FIG. 1) in which the image forming apparatus 100 can be used is defined as the up-down direction (Z1-Z2 direction). In addition, the front side of the paper of the image forming apparatus 100 shown in FIG. 1 is defined as the front (front face) and the front-rear direction (Y1-Y2 direction) is defined. In addition, the left-right direction (X1-X2 direction) is defined with the front face of the image forming apparatus 100 in the installation state as a reference. In this embodiment, the left-right direction (X1-X2 direction) is perpendicular to the up-down direction (Z1-Z2 direction) and the front-rear direction (Y1-Y2 direction).

[0010] The image forming apparatus 100 includes an optical scanning device 5, photosensitive drums (image carriers) 1a-1d, charging devices 2a-2d, developing devices 3a-3d, primary transfer rollers 6a-6d, a secondary transfer roller 9, a paper feed cassette 16, a fixing unit 13, and a control unit 50.

[0011] Specifically, the image forming apparatus 100 is a tandem type color printer. The image forming apparatus 100 includes rotatable photoconductor drums 1a to 1d as image carriers. For the photoconductor drums 1a to 1d, an organic photoconductor (OPC photoconductor) having an organic photosensitive layer formed thereon, or an amorphous silicon photoconductor having an amorphous silicon photosensitive layer formed thereon, or the like, is used. The photoconductor drums 1a to 1d are arranged in tandem corresponding to the respective colors of yellow, cyan, magenta, and black.

[0012] Around the photoconductor drum (image carrier) 1a, a developing device 3a, a charger 2a, and a cleaning device 7a are arranged. Similarly, around the photoconductor drums 1b to 1d, developing devices 3b to 3d, chargers 2b to 2d, and cleaning devices 7b to 7d are arranged, respectively. In addition, an optical scanning device 5 is arranged above Z1 the developing devices 3a to 3d.

[0013] The developing devices 3a to 3d are disposed on the right side X1 of the photoconductor drums 1a to 1d, respectively. The developing devices 3a to 3d are disposed facing the photoconductor drums (image carriers) 1a to 1d, and have developing rollers (developer carriers) 21a to 21d. The developing devices 3a to 3d apply a predetermined developing voltage to the developing rollers (developer carriers) 21a to 21d to attach toner to the electrostatic latent images formed on the photoconductor drums (image carriers) 1a to 1d, forming toner images. The developing devices 3a to 3d face the photoconductor drums 1a to 1d, respectively, and supply toner to the photoconductor drums 1a to 1d. The developing devices 3a to 3d have containers 4a to 4d, in which magenta, cyan, yellow, and black toners are stored.

[0014] The chargers 2a to 2d are disposed upstream of the developing devices 3a to 3d in the rotation direction of the photoconductor drums 1a to 1d and face the surfaces of the photoconductor drums 1a to 1d, respectively. The chargers 2a to 2d uniformly charge the surfaces of the photoconductor drums 1a to 1d, respectively.

[0015] In this embodiment, the optical scanning device 5 is disposed above the photoconductor drums 1a-1d at Z1. The optical scanning device 5 irradiates light (optical scanning) onto the surfaces of the photoconductor drums 1a-1d uniformly charged by the chargers 2a-2d based on image data such as characters and patterns input to an image input unit from a personal computer or the like. As a result, electrostatic latent images are formed on the surfaces of the photoconductor drums 1a-1d.

[0016] The housing 48 of the optical scanning device 5 is a resin molded product, and includes a housing portion 481 having one opening on one surface (the upper surface in this embodiment) and a lid portion 482 that covers the opening (see FIG. 4). The housing portion 481 houses the scanning optical system therein.

[0017] The laser beams D1 to D4 are irradiated onto the surfaces of the photoconductor drums 1a to 1d from downstream of the chargers 2a to 2d in the direction of rotation of the photoconductor drums 1a to 1d, respectively. As a result, electrostatic latent images are formed on the surfaces of the photoconductor drums 1a to 1d. These electrostatic latent images are developed into toner images by the developing devices 3a to 3d.

[0018] An endless intermediate transfer belt 8 is stretched around a drive roller 10 and a driven roller 11. When the drive roller 10 is rotated by a motor (not shown), the intermediate transfer belt 8 is driven to circulate in the clockwise direction in FIG.

[0019] The photoconductor drums 1a to 1d are arranged adjacent to each other along the transport direction (the direction of the arrow in FIG. 1) above the intermediate transfer belt 8. The photoconductor drums 1a to 1d are in contact with the intermediate transfer belt 8, respectively.

[0020] The primary transfer rollers 6a to 6d face the photoconductor drums 1a to 1d, respectively, with the intermediate transfer belt 8 therebetween. The primary transfer rollers 6a to 6d are pressed against the intermediate transfer belt 8, respectively, and form primary transfer portions together with the photoconductor drums 1a to 1d. In these primary transfer portions, toner images are transferred to the intermediate transfer belt 8.

[0021] Specifically, a primary transfer voltage is applied to the primary transfer rollers 6a to 6d, so that the toner images on the photoconductor drums 1a to 1d are transferred sequentially at a predetermined timing onto the intermediate transfer belt 8. As a result, a full-color toner image is formed on the surface of the intermediate transfer belt 8, in which toner images of four colors, magenta, cyan, yellow, and black, are superimposed in a predetermined positional relationship.

[0022] The secondary transfer roller 9 faces the drive roller 10 with the intermediate transfer belt 8 sandwiched therebetween. The secondary transfer roller 9 is pressed against the intermediate transfer belt 8 and forms a secondary transfer section together with the drive roller 10. In this secondary transfer section, a secondary transfer voltage is applied to the secondary transfer roller 9, so that the toner image on the surface of the intermediate transfer belt 8 is transferred to the paper S. After the toner image is transferred, a belt cleaning device (not shown) cleans off any toner remaining on the intermediate transfer belt 8.

[0023] A paper feed cassette 16 is disposed at the bottom inside the image forming apparatus 100. The paper feed cassette 16 is capable of storing a plurality of sheets of paper S. To the right X1 of the paper feed cassette 16, a paper transport path 19 is disposed.

[0024] The paper transport path 19 transports the paper S fed from the paper feed cassette 16 to the secondary transfer unit. A fixing unit 13 and a paper transport path 20 are disposed in the upper right corner of the image forming apparatus 100. The fixing unit 13 performs a fixing process on the paper S on which an image has been formed. The paper transport path 20 transports the paper S which has been subjected to the fixing process to the paper discharge unit 17.

[0025] The sheets S stored in the paper feed cassette 16 are fed one by one to the paper transport path 19 side by the pickup roller 12a.

[0026] The pair of registration rollers 12b transports the paper S to the secondary transfer section in accordance with the timing of the image forming operation on the intermediate transfer belt 8 and the paper feeding operation to the secondary transfer section. The full-color toner image on the intermediate transfer belt 8 is secondarily transferred onto the paper S transported to the secondary transfer section by a secondary transfer roller 9 to which a secondary transfer voltage is applied. The paper S to which the full-color toner image has been transferred is transported to a fixing section 13.

[0027] The fixing unit 13 includes a fixing belt heated by a heater, a fixing roller in contact with the fixing belt, and a pressure roller pressed against the fixing roller with the fixing belt sandwiched therebetween. The fixing unit 13 heats and presses the paper S onto which the toner image has been transferred. This performs the fixing process. The paper S onto which the toner image has been fixed in the fixing unit 13 is turned over in the paper transport path 18 as necessary. The paper S is then transported again to the secondary transfer unit via the pair of registration rollers 12b, after which a new toner image is secondarily transferred onto the rear surface of the paper S by the secondary transfer roller 9, and fixed in the fixing unit 13. The paper S onto which the toner image has been fixed passes through the paper transport path 20 and is discharged to the paper discharge unit 17.

[0028] A control unit 50 is also disposed inside the image forming apparatus 100. The control unit 50 comprehensively controls the image forming apparatus 100. Specifically, the control unit 50 controls the image forming unit. The image forming unit includes an optical scanning device 5, photoconductor drums (image carriers) 1a-1d, charging devices 3a-3d, and developing devices 3a-3d. That is, the control unit 50 controls the optical scanning device 5 and the developing devices 3a-3d.

[0029] [2. Configuration of optical scanning device] 2 and 3 are perspective views of the optical scanning device 5, and FIG. 3 shows a state in which the cover 482 is removed. FIG. 4 is a cross-sectional view taken along line AA in FIG. 2. A part of FIG. 4 shows the configuration of each member in a schematic manner, and does not strictly show the shape and positional relationship of each member. Also, FIG. 4 does not show the scanning lens 41 and the scanning lens 42.

[0030] In the following description, the main scanning direction (Y1-Y2 direction) is the longitudinal direction of the reflecting mirrors 49a to 49c. The main scanning direction (Y1-Y2 direction) coincides with the direction in which the rotation axes of the photosensitive drums 1a to 1d extend and with the front-rear direction of the image forming apparatus 100. The sub-scanning direction (Z1-Z2 direction) is parallel to the rotation axis J of the polygon mirror 45 and coincides with the up-down direction of the image forming apparatus 100. The left-right direction (X1-X2 direction) is perpendicular to the main scanning direction (Y1-Y2 direction) and the sub-scanning direction (Z1-Z2 direction), and coincides with the juxtaposition direction of the reflecting mirrors 49a to 49c.

[0031] The optical scanning device 5 outputs (irradiates) multiple (four in this embodiment) laser beams D1 to D4 modulated according to each image signal onto the photosensitive drums 1a to 1d, exposing the surfaces of the photosensitive drums 1a to 1d to form electrostatic latent images with attenuated charge.

[0032] The optical scanning device 5 includes a light source unit 46, a polygon mirror 45, a pair of scanning lenses 41, a pair of scanning lenses 42, a pair of reflecting mirrors 49a, 49b, and 49c, a housing 48, and a circuit board 90.

[0033] The housing 48 includes a storage section 481 and a cover section 482. The storage section 481 is formed in a substantially rectangular shape when viewed from above. The storage section 481 stores the light source section 46, the polygon mirror 45, the pair of scanning lenses 41, the pair of scanning lenses 42, the pair of reflecting mirrors 49a, 49b, and 49c, and the circuit board 90.

[0034] The storage section 481 has a bottom wall section 481a and a peripheral wall section 481b. The bottom wall section 481a expands in a direction perpendicular to the rotation axis J of the polygon mirror 45. The bottom wall section 481a has exit ports 483a to 483d penetrating in the up-down direction (see FIG. 4). The exit ports 483a to 483d extend in the main scanning direction (Y1-Y2 direction). The laser beams D1 to D4 emitted from the scanning optical system are emitted to the outside of the housing 48 through the exit ports 483a to 483d and enter the corresponding photoconductor drums 1a to 1d, respectively. The exit ports 483a to 483d are covered with dustproof glasses 70a to 70d, respectively. This makes it possible to prevent dust from entering the inside of the housing 48.

[0035] An opening 483e is formed in the bottom wall 481a, penetrating in the vertical direction (see FIG. 5). In this embodiment, the opening 483e is disposed behind (on the Y2 side of) the light source unit 46, and opens facing the photosensitive drums (image carriers) 1a to 1d and the developing devices 3a to 3d. A temperature sensor (thermistor) 91, which will be described later, is disposed in the housing 48, facing the opening 483e. This allows the temperature sensor 91 to accurately detect the temperatures of the developing devices 3a to 3d from inside the housing 48. For example, the temperature sensor 91 can accurately detect the temperatures of the developing rollers (developer carriers) 21a to 21d of the developing devices 3a to 3d.

[0036] The peripheral wall portion 481b extends upward from the outer periphery of the bottom wall portion 481a and surrounds the light source portion 46, the polygon mirror 45, the pair of scanning lenses 41, the pair of scanning lenses 42, the pair of reflecting mirrors 49a, 49b, 49c, and the circuit board 90 from the sides.

[0037] The lid portion 482 has a top surface portion 482a and a peripheral surface portion 482b. The top surface portion 482a covers the open upper surface of the storage portion 481. The peripheral surface portion 482b extends downward from the outer periphery of the top surface portion 482a and covers a part of the peripheral wall portion 481b from the radially outer side.

[0038] The light source unit 46 has a plurality of light-emitting modules 46a that emit laser light. Each of the light-emitting modules outputs laser light D1 to D4 corresponding to each color of Y (yellow), C (cyan), M (magenta), and K (black). The laser light D1 to D4 emitted from each of the light-emitting modules 46a is irradiated onto a polygon mirror 45. The laser light D1 to D4 forms a line image near the deflection surface of the polygon mirror 45.

[0039] In this embodiment, the circuit board 90 is disposed behind (on the Y2 side) the light source unit 46, and is held in an accommodation unit 481 in an upright state perpendicular to the main scanning direction (Y1-Y2 direction) (see FIG. 3). A temperature sensor 91 and an IC driver 92, which will be described later, are mounted on the circuit board 90. The circuit board 90 will be described in detail later.

[0040] Polygon mirror 45 rotates around rotation axis J extending in the vertical direction (Z1-Z2 direction) to reflect laser beams D1 to D4 emitted from light source unit 46, and scans the peripheral surfaces of photosensitive drums (image carriers) 1a to 1d in the main scanning direction.

[0041] The polygon mirror 45 is composed of a plurality of reflecting surfaces. In this embodiment, the polygon mirror 45 is a polygonal mirror formed in a quadrangular prism shape. The laser beams D1 and D2 incident on the polygon mirror 45 are deflected and scanned by any of the reflecting surfaces that rotate, reflected in the left direction (X2 direction) by the reflecting surface of the polygon mirror 45, and guided to the scanning lenses 41 and 42. On the other hand, the laser beams D3 and D4 incident on the polygon mirror 45 are deflected and scanned by any of the reflecting surfaces that rotate, reflected in the right direction (X1 direction) by the reflecting surface of the polygon mirror 45, and guided to the scanning lenses 41 and 42 (see FIG. 4).

[0042] The scanning lens 42 is disposed downstream of the scanning lens 41 in the optical paths of the laser beams D1 to D4.

[0043] The scanning lens 41 is a lens having distortion (fθ characteristics) and is a long lens extending along the main scanning direction (Y1-Y2 direction). The scanning lens 41 collects the laser beams D1 to D4 reflected by the deflection surface of the polygon mirror 45.

[0044] The scanning lens 42 is a lens having distortion aberration (fθ characteristics) similar to the scanning lens 41, and is a long lens extending along the main scanning direction (Y1-Y2 direction). The scanning lens 42 collects the laser beams D1 to D4 that have passed through the scanning lens 41, and forms images on the scanned surfaces of the photosensitive drums 1a to 1d, respectively.

[0045] The pair of reflecting mirrors 49a reflect the laser beams D1 and D4, respectively. The pair of reflecting mirrors 49b and the pair of reflecting mirrors 49c reflect the laser beams D2 and D3, respectively.

[0046] Scanning lenses 41 and 42 form images of laser beams D1 to D4 reflected by polygon mirror 45 on the scanned surfaces (circumferential surfaces) of photosensitive drums (image carriers) 1a to 1d.

[0047] The laser beams D1 to D4 reflected and deflected by the polygon mirror 45 pass through the scanning lens 41 and the scanning lens 42 and are condensed onto the scanned surfaces of the photosensitive drums 1a to 1d, respectively. As a result, beam spots are formed on the scanned surfaces of the photosensitive drums 1a to 1d. The laser beams D1 to D4 condensed onto the scanned surfaces of the photosensitive drums 1a to 1d scan the scanned surfaces of the photosensitive drums 1a to 1d at a constant speed.

[0048] At this time, the laser beams D1 to D4 scan the scanned surfaces (circumferential surfaces) of the photoconductor drums (image carriers) 1a to 1d in the main scanning direction (Y1-Y2 direction) due to the rotation of the polygon mirror 45. Also, the laser beams D1 to D4 scan in the sub-scanning direction (Z1-Z2 direction) due to the rotation of the photoconductor drums 1a to 1d to form electrostatic latent images on the surfaces of the photoconductor drums 1a to 1d.

[0049] [3. Configuration of Circuit Board 90] 5 is an explanatory diagram showing an enlarged view of the vicinity of the circuit board 90. In this embodiment, the circuit board 90 is disposed behind (on the Y2 side) the light source unit 46, and is held in an accommodating unit 481 in an upright state perpendicular to the main scanning direction (Y1-Y2 direction) (see FIG. 3). A temperature sensor 91 and an IC driver 92 are mounted on the circuit board 90. The temperature sensor 91 is disposed on the circuit board 90 on the opposite side to the IC driver 92 with an external connection terminal 93 interposed therebetween. The temperature sensor 91 detects the temperature inside the housing 48, and also detects the temperatures of the developing devices 3a to 3d.

[0050] In this embodiment, the temperature sensor 91 is disposed at the lower end of the circuit board 90 and faces the opening 483e. This allows the temperature sensor 91 to detect the temperatures of the developing devices 3a to 3d from inside the housing 48 with high accuracy.

[0051] In addition, a duct 80 is disposed between the optical scanning device 5 and the photosensitive drums (image carriers) 1a to 1d. The duct 80 covers the rear (Y2) ends of the developing devices 3a to 3d in the main scanning direction (Y1-Y2 direction) from above, and guides the heat of the developing devices 3a to 3d to the temperature sensor 91. The internal flow path 80a of the duct 80 narrows toward the temperature sensor 91 (upward Z1 direction). This allows the temperature sensor 91 to detect the temperatures of the developing devices 3a to 3d from inside the housing 48 with higher accuracy.

[0052] The IC driver 92 is connected to the control unit 50 described above. The IC driver 92 is connected to the light source unit 46 and the temperature sensor 91. The control unit 50 transmits a signal to the light source unit 46 via the IC driver (control unit) 92 based on the temperature inside the housing 48 detected by the temperature sensor 91. In this way, the control unit 50 controls the scanning start timing (light emission timing) of the laser beams D1 to D4 emitted by the light source unit 46. Therefore, color shifts and the like can be corrected and image defects can be suppressed.

[0053] The control unit 50 can also control the rotation of the polygon mirror 45 based on the temperature inside the housing 48 detected by the temperature sensor 91. By controlling the light emission timing of the light source unit 46 and controlling the rotation of the polygon mirror 45 based on the temperature inside the housing 48 detected by the temperature sensor 91, it is possible to correct color shifts and further suppress image defects.

[0054] Although the IC driver 58 generates heat during operation, the temperature sensor 91 is disposed on the circuit board 90 on the opposite side of the IC driver 92 with the external connection terminal 93 in between, and is therefore less susceptible to the heat generated by the IC driver 58. This makes it possible to precisely control the emission timing of the light source unit 46 based on the temperature detected by the temperature sensor 91.

[0055] Furthermore, control unit 50 is connected to developing devices 3a-3d, and control unit 50 is also capable of controlling developing devices 3a-3d based on the temperatures of developing devices 3a-3d detected by temperature sensor 91. By sharing temperature sensor 91 that detects the temperature inside housing 48 and that detects the temperatures of developing devices 3a-3d, it is possible to provide image forming apparatus 100 that can suppress the occurrence of image defects while suppressing increases in manufacturing costs.

[0056] Specifically, the control unit 50 controls the magnitude of the developing voltage based on the temperature of the developing devices 3a-3d detected by the temperature sensor 91. By controlling the magnitude of the developing voltage, the image density of the toner image can be adjusted. Furthermore, the control unit 50 stops driving the developing devices 3a-3d when the temperature of the developing devices 3a-3d detected by the temperature sensor 91 exceeds a predetermined threshold value. This makes it possible to prevent development defects by stopping the driving of the developing devices 3a-3d in advance before problems occur due to aggregation or characteristic changes of toner, etc. in the developing devices 3a-3d.

[0057] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. [Industrial Applicability]

[0058] The present invention can be used in an optical scanning device that forms a latent image on a scanned surface by exposure scanning. [Explanation of symbols]

[0059] 1a to 1d Photoconductor drum (image carrier) 2a~2d Charger 3a~3d developing device 4a~4d Container 5 Optical Scanning Device 6a~6d Primary transfer roller 7a~7d Cleaning device 8 Intermediate transfer belt 9 Secondary transfer roller 10 Drive roller 11 Driven roller 12a Pick-up roller 12b Registration roller pair 13 Fixing section 16 Paper feed cassette 17, 18, 19, 20 Paper transport path 41 Scanning Lens 42 Scanning Lens 45 Polygon Mirror 46 Light source section 48 Case 49a, 49b, 49c Reflecting mirror 50 Control section 70a~70d Dustproof glass 80 Duct 80a Internal flow path 90 Circuit Board 91 Temperature sensor (thermistor) 92 IC Driver 93 External connection terminal 100 Image forming device 481 Storage Unit 481a Bottom wall 481b Peripheral wall 482 Lid 482a Top section 482b Peripheral part 483a~483d Output port 483e opening D1~D4 Laser light J Rotation axis S paper

Claims

1. A light source unit that emits laser light; a polygon mirror that rotates about a rotation axis extending in a vertical direction to reflect the laser light emitted from the light source unit and scans the peripheral surface of an image carrier in a main scanning direction; a scanning lens that forms an image of the laser light reflected by the polygon mirror on a peripheral surface of the image carrier; a housing that accommodates the light source unit, the polygon mirror, and the scanning lens; a temperature sensor for detecting a temperature inside the housing; an optical scanning device including: One or more of the image carriers each having a photosensitive layer formed on a surface thereof; a charging device for charging the image carrier to a predetermined surface potential; a developing device disposed opposite to the image carrier, the developing device having a developer carrier that carries a developer, and applying a predetermined developing voltage to the developer carrier to cause toner to adhere to an electrostatic latent image formed on the image carrier, thereby forming a toner image; A control unit that controls the optical scanning device and the developing device; Equipped with the temperature sensor detects a temperature of the developing device; The control unit controls the optical scanning device based on a temperature inside the housing detected by the temperature sensor, and controls the developing device based on a temperature of the developing device detected by the temperature sensor.

2. An IC driver for controlling the light source unit; The IC driver further includes a circuit board mounted on the circuit board and housed in the housing; 2. The image forming apparatus according to claim 1, wherein the temperature sensor is mounted on the circuit board and is disposed on the circuit board on an opposite side to the IC driver across an external connection terminal.

3. the housing has an opening facing the developing device, 3. The image forming apparatus according to claim 1, wherein the temperature sensor is disposed inside the housing and faces the opening.

4. the optical scanning device is disposed adjacent to and above the developing device, 3. The image forming apparatus according to claim 1, further comprising a duct disposed between the optical scanning device and the developing device, for guiding heat of the developing device to the temperature sensor.

5. The image forming apparatus according to claim 4 , wherein an internal flow path of the duct narrows toward the temperature sensor.

6. The image forming apparatus according to claim 5 , wherein the control section controls the magnitude of the developing voltage based on the temperature of the developing device detected by the temperature sensor.

7. The image forming apparatus according to claim 6 , wherein the control unit stops driving the developing device when the temperature of the developing device detected by the temperature sensor exceeds a predetermined threshold value.

Images