JP5836769B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a color laser beam printer or a color digital copying machine using a scanning optical device.

  In a scanning optical device used in a laser beam printer, a digital copying machine, or the like, a light beam that is light-modulated and emitted from a light source unit according to an image signal is periodically deflected by an optical deflector such as a rotating polygon mirror, for example. Let it scan. Then, imaging optics having an fθ characteristic (a characteristic of a lens that forms an image of a size (Y = f × θ) obtained by multiplying the focal length f of the lens when the scanning beam enters at an angle θ). The beam is focused on the image forming surface on the photosensitive drum by the system.

  The spot on the imaging surface forms an electrostatic latent image in accordance with the main scanning by the optical deflector and the sub scanning by the rotation of the photosensitive drum, and image recording is performed.

  In recent years, the rotational speed of rotating polygon mirrors has become tens of thousands of rpm due to the demand for higher density and faster printing of images from the market. When the rotating polygon mirror is rotated at a high speed, dust contained in the air is sucked into the optical scanning device and is struck against the reflecting surface of the rotating polygon mirror, and the reflecting surface of the rotating polygon mirror becomes dirty.

  On the other hand, the scanner motor rotating the rotary polygon mirror needs to supply power and a control signal from the outside, and a through hole communicating with the outside is necessary in the vicinity of the scanner motor. However, since dust is sucked from the through-hole, it is important to close the through-hole when the rotating polygon mirror is rotated at a high speed.

  A scanning optical device described in Patent Document 1 is generally known as a scanning optical device that takes measures against contamination on the reflecting surface of the rotary polygon mirror as described above. In this configuration, a cable is passed through a cutout in a side wall provided on the side of the optical box, the scanner motor is electrically connected, and then the through hole is closed with a sealing member.

JP-A-9-26553 (FIG. 2B)

  However, as described above, in the configuration in which the notch of the side wall of the optical box is filled with the sealing member and the scanning optical device is sealed, the sealing member is detached when an impact or vibration is applied to the scanning optical device, There is a problem that the sealing cannot be maintained.

  Further, when the sealing member is buried, the sealing member may be shifted or twisted, and sufficient sealing performance may not be realized.

  With the recent increase in printing speed of image forming apparatuses, the number of rotations of the rotating polygon mirror increases, and the suction force generated by the rotating polygon mirror also increases. Therefore, if there is even an opening or a gap even in the vicinity of the rotating polygon mirror, a large amount of outside air is sucked from there, and the reflecting surface of the rotating polygon mirror is rapidly contaminated. As a result, the reflectance of the rotating polygon mirror is reduced, and printing defects such as thin images occur.

  In order to solve the above problem, it is necessary to clean the reflecting surface of the rotating polygon mirror or replace the rotating polygon mirror. However, this causes another problem that the maintenance cost increases significantly.

  The above trouble is a major obstacle to the high performance of the deflection scanning device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that is less likely to cause printing defects such as image thinness due to the ingress of dust and that has a long life and excellent maintainability.

In order to achieve the above object, a typical configuration of an image forming apparatus according to the present invention includes a deflecting unit that converts a light beam generated from a light source into scanning light, and an imaging that forms the scanning light on a photosensitive member. Means, an optical box for accommodating the deflecting means and the imaging means, a lid for sealing the opening of the optical box, a control means disposed outside the optical box, and fixing the optical box An optical bench, the control means, a connecting means for electrically connecting the driving means of the deflecting means, and the optical bench facing the optical bench to draw the connecting means out of the optical box. A through hole provided in the surface to be sealed, and a sealing member that seals between the through hole and the outside air, and the sealing member is disposed in a recess provided in the optical bench facing the through hole. while being fitted, the sealing member is in said optical bench and the optical box Characterized in that it is Rikyoji.

  ADVANTAGE OF THE INVENTION According to this invention, the dustproof effect of an optical box can be improved, printing defects, such as image thinness by the entrance of dust, can be suppressed, and the image forming apparatus excellent in maintainability with long life can be provided. .

1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus according to the present invention. It is a perspective explanatory view showing the configuration of the scanning optical device. 1 is an explanatory cross-sectional view illustrating a configuration of a first embodiment of an image forming apparatus according to the present invention. It is a section explanatory view showing the important section of a 1st embodiment. It is a disassembled perspective view which shows the structure of 1st Embodiment. FIG. 6 is a perspective explanatory view illustrating a configuration of a second embodiment of the image forming apparatus according to the present invention. It is sectional explanatory drawing which shows the principal part of 2nd Embodiment. FIG. 9 is an explanatory cross-sectional view illustrating a configuration of a third embodiment of an image forming apparatus according to the present invention.

  An embodiment of an image forming apparatus according to the present invention will be specifically described with reference to the drawings.

  First, the configuration of the first embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS.

<Configuration of image forming apparatus>
FIG. 1 is a view showing an image forming apparatus 26 equipped with a scanning optical device 5. In FIG. 1, a scanning optical device 5 that generates a laser beam 8 to be a light beam is installed on an optical bench 23.

  A process cartridge 9, which is an image carrier that forms an electrostatic latent image upon receipt of the laser beam 8 and is a developing means incorporating a photosensitive drum 19 as a photosensitive member, is disposed below the scanning optical device 5. It is incorporated inside the forming device 26. The process cartridge 9 is detachable in the direction of arrow a in FIG.

  A recording material 40 such as paper or an OHT (OverHead Transparency) sheet (a transparent sheet used for an OHP (OverHead Projector)) is supplied from the feeding cassette 15 or the feeding tray 13. The recording material 40 is transported along the transport path 16 by transport rollers 14, 11, 10, 20, 22 and the discharge roller 1.

  The laser beam 8 emitted from the emission port 5a provided at the lower part of the frame of the scanning optical device 5 shown in FIG. 2 scans the surface of the photosensitive drum 19 that is uniformly charged by the charging roller 43 to obtain image information. Based on the electrostatic latent image, a surface of the photosensitive drum 19 is formed.

  The electrostatic latent image formed on the surface of the photosensitive drum 19 is developed with toner by the developing device 17, and the image information is transferred to the recording material 40 conveyed along the conveying path 16 by the transfer roller 18. Further, when the recording material 40 passes through the fixing unit 21, the toner is fixed on the recording material 40 by heat and is discharged to the discharge portion 46.

  As shown in FIG. 2, the scanning optical device 5 includes a rotating polygon mirror 7 serving as a deflecting unit that converts a laser beam 8 generated from a laser light source unit 2 serving as a light source that generates a light beam into scanning light. A scanner motor 51 serving as a driving unit is included. The scanner motor 51 is electrically connected to a controller 42 serving as control means disposed outside the optical box 3 via a cable 54 as connection means.

<Configuration of scanning optical device>
FIG. 2 is a diagram illustrating the configuration of the scanning optical device 5. The laser beam 8 emitted from the laser light source unit 2 is limited to a predetermined beam diameter by the optical diaphragm 4 formed in the optical box 3. The optical box 3 accommodates a rotary polygon mirror 7 and an fθ lens 24 that serves as an image forming means for forming an image of the scanning light on the photosensitive drum 19.

  Then, it is condensed only in the sub-scanning direction by the cylindrical lens 6, and is condensed into a long line in the main scanning direction on the laser beam reflecting surface 12 of the rotary polygon mirror 7. The rotary polygon mirror 7 is rotationally driven by the scanner motor 51 to deflect the incident laser beam 8. The deflected laser beam 8 passes through the fθ lens 24, is reflected by the folding mirror 25, and is condensed and scanned on the surface of the photosensitive drum 19 to form an electrostatic latent image.

  The fθ lens 24 is designed so that the laser beam 8 is condensed so as to form a spot on the surface of the photosensitive drum 19 and the scanning speed of the spot is kept constant. In order to obtain such characteristics of the fθ lens 24, the fθ lens 24 is formed of an aspheric lens.

  A part of the deflected laser beam 8 is guided to the synchronization detection sensor 27 to detect the synchronization of the writing position in the main scanning direction. The scanner motor 51 is fixed to a boss 28 formed on the optical box 3 with screws 29. In the scanning optical device 5, as shown in FIG. 5, the optical box 3 is fixed to the optical bench 23 with screws 56. The opening of the optical box 3 is sealed with a lid 41 shown in FIG.

<Configuration of scanner motor>
The configuration of the scanner motor 51 will be described in detail with reference to FIG. FIG. 3 is a schematic cross-sectional view of the scanner motor 51 provided in the present embodiment.

  First, the rotor unit 50 of the scanner motor 51 will be described. The rotor unit 50 includes a rotating shaft 31, a flange member 32, a rotor yoke 49, and a rotor magnet 33. The rotating shaft 31 is supported on the optical box 3 via a sleeve 30 serving as a bearing. The flange member 32 provided integrally with the rotating shaft 31 is coupled integrally with the rotor yoke 49. The rotor yoke 49 is integrally coupled to the rotor magnet 33.

  Next, the substrate and the stator portion of the scanner motor 51 will be described. The iron substrate 34 is provided integrally with the sleeve 30, and the stator core 35 and the stator coil 36 are fixed thereto.

  Further, an electronic component 38 such as an integrated circuit is mounted on the iron substrate 34 as a driving means for the rotary polygon mirror 7 on the same surface as the rotor portion 50 (the upper surface side of the iron substrate 34 in FIG. 3). Further, on the surface opposite to the rotor portion 50 (the lower surface side of the iron substrate 34 in FIG. 3), the electronic component 38 and the scanner motor 51 that are the driving means of the rotary polygon mirror 7 that is the deflecting means and the connecting means. A connector 37 is mounted as a coupling portion that electrically connects the cable 54.

<Configuration around the connector>
Next, the configuration near the connector 37 will be described with reference to FIG. 4 is a detailed view of part A in FIG. A through hole 39 is provided in the bottom wall 3a which is a surface facing the optical bench 23 of the optical box 3 in order to pull out the cable 54 of the optical box 3 near the scanner motor 51 to the outside of the optical box 3. .

  The connector 53 connected to the connector 37 serving as a coupling portion is connected to the connector 37 through the through hole 39. On the other hand, the connector 53 serving as a coupling portion is integrated with the cable 54 and is electrically connected to the controller 42 serving as the control means shown in FIG.

  In other words, in the present embodiment, the connectors 37 and 53 that are connecting portions that electrically connect the electronic component 38 and the scanner motor 51 that are driving means of the rotary polygon mirror 7 that is deflecting means and the cable 54 that is connecting means. Is provided. The connectors 37 and 53 are provided on the back side of the iron substrate 34 which is the surface facing the optical bench 23 through the through hole 39 provided in the bottom wall 3a on the back side of the iron substrate 34 which is the substrate of the rotary polygon mirror 7. Is provided.

  After connecting the connector 53 to the connector 37, the through hole 39 is sealed by a sealing member 52 that seals between the through hole 39 and the outside air. As shown in FIG. 5, the sealing member 52 of the present embodiment has a hexahedron shape having an area larger than the diameter of the through hole 39, and is configured to directly block the through hole 39.

  As a material of the sealing member 52, urethane foam, elastomer, or the like can be applied. Further, the sealing member 52 is fitted into a recess 55 (in the recess) formed in the optical bench 23 so as to face the through hole 39 and is sandwiched between the optical bench 23 and the bottom wall 3 a of the optical box 3. Compressed. The recess 55 is formed by drawing into a shape corresponding to the area and height of the sealing member 52.

<Assembly of scanning optical device and optical bench>
Next, a method for assembling the scanning optical device 5 and the optical bench 23 will be described with reference to FIG. First, the sealing member 52 is fitted and disposed in the recess 55. At that time, the sealing member 52 may be fixed to the surface of the concave portion 55 of the optical bench 23 with a double-sided tape or the like. Next, the scanning optical device 5 is fastened to the optical bench 23 with screws 56. At that time, the sealing member 52 is sandwiched and compressed between the bottom wall 3 a of the optical box 3 of the scanning optical device 5 and the optical bench 23. Thereby, the sealing member 52 seals the through hole 39 in a compressed state.

  According to this embodiment, the through hole 39 of the optical box 3 necessary for the scanner motor 51 to be electrically connected to the outside is installed on the back side of the iron substrate 34 of the scanner motor 51. As a result, the iron substrate 34 serves as a shield against the rotary polygonal mirror 7 serving as a pressure source for sucking outside air, and the force for sucking outside dust from the through hole 39 can be weakened.

  Further, since the sealing member 52 is sandwiched between the optical box 3 and the optical bench 23, the sealing member 52 is compressed and the confidentiality of the scanning optical device 5 is improved. Further, it is possible to prevent the sealing member 52 from being detached when an impact or vibration is applied to the image forming apparatus 26.

  Next, the configuration of the second embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to the said 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

  In the first embodiment, the through hole 39 is directly closed by the hexahedral sealing member 52. In this embodiment, a sealing member 61 that seals between the through hole 39 and the outside air is formed in an annular shape surrounding the through hole 39 and fixed to the bottom wall 3 a of the optical box 3. The sealing member 61 of the present embodiment is an example configured with a rectangular annular shape having a through hole 63 having an inner diameter larger than the diameter of the through hole 39. In addition to the square shape, a ring shape and various annular shapes can be applied. As a material of the sealing member 61, urethane foam, elastomer, or the like can be applied.

  FIG. 6 is a perspective view of the scanning optical device 5 as viewed from below. In the scanning optical device 5, the sealing member 61 is attached in advance to the bottom surface 3 a 1 of the bottom wall 3 a that is a surface facing the optical bench 23 of the optical box 3. The sealing member 61 is pasted so as to surround the through hole 39, and a through hole 63 through which the cable 54 and the connector 53 are passed is provided.

  FIG. 7 shows a state in which the scanning optical device 5 is assembled to the optical bench 23. The scanning optical device 5 is fixed to the optical bench 23. At that time, the sealing member 61 is sandwiched and compressed by the bottom wall 3a of the optical box 3 of the scanning optical device 5 and the optical bench 23, and the through hole 39 provided in the bottom wall 3a of the optical box 3 and the outside air are Seal the gap. Other configurations are the same as those in the first embodiment, and the same effects can be obtained.

  Next, the configuration of the third embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. In addition, what was comprised similarly to each said embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

  In each of the above-described embodiments, the sealing member 52, 61 is used to seal between the through hole 39 and the outside air. In this embodiment, the space between the through hole 39 provided in the bottom wall 3a of the optical box 3 and the outside air is sealed by a plurality of sealing members 61 and 71 stacked on each other. The cable 54 is held between the plurality of sealing members 61 and 71. As the material of the sealing member 71, urethane foam, elastomer, or the like can be applied.

  In the present embodiment, two sealing members 61 and 71 are sandwiched between the optical box 3 and the optical bench 23. As in the second embodiment, the sealing member 61 that seals between the through hole 39 and the outside air is formed in a rectangular shape surrounding the periphery of the through hole 39, and the bottom surface of the bottom wall 3a of the optical box 3 Affixed to 3a1 and fixed. The sealing member 61 has a rectangular annular shape having a through hole 63 having an inner diameter larger than the diameter of the through hole 39. The sealing member 71 has a larger area than the diameter of the through-hole 63 of the sealing member 61 and is formed in a hexahedron shape. Is done. The sealing member 71 is configured to indirectly close the through hole 39 via the sealing member 61.

  According to the present embodiment, by holding the cable 54 from above and below by the two sealing members 61 and 71 having elasticity, it is possible to more effectively prevent the generation of a small gap near the cable 54. Therefore, it is possible to further enhance the airtightness when the space between the through hole 39 of the optical box 3 provided for electrically connecting the scanner motor 51 to the outside and the outside air is sealed. As a result, the dustproof effect of the scanning optical device 5 can be further enhanced.

  In addition, although this embodiment demonstrated the structure in case there are two sealing members 61 and 71, it cannot be overemphasized that it is good also as a structure which uses three or more sealing members depending on the shape of a sealing member. Other configurations are the same as those in the above embodiments, and the same effects can be obtained.

  In each of the above embodiments, the connecting means for electrically connecting the scanner motor 51 serving as the driving means of the rotary polygon mirror 7 and the controller 42 serving as the control means disposed outside the optical box 3. The cable 54 has been described as an example. As other connection means, an FFC (flexible flat cable) having a flat electric wire structure and a significantly reduced thickness can be applied, and the connection means is not limited by the type of the cable 54.

2 ... Laser light source unit (light source)
3 Optical box 7 Rotating polygon mirror (deflection means)
8 ... Laser beam (light beam)
19… Photosensitive drum (photoconductor)
23 Optical stage
24 fθ lens (imaging means)
39… through hole
41… Lid
42 ... Controller (control means)
51… Scanner motor (drive means)
52… Sealing member
54… Cable (connection means)

Claims (5)

Deflection means for converting a light beam generated from a light source into scanning light;
An imaging means for imaging the scanning light on a photoconductor;
An optical box that houses the deflecting means and the imaging means;
A lid for sealing the opening of the optical box;
Control means disposed outside the optical box;
An optical bench for fixing the optical box;
Connection means for electrically connecting the control means and the drive means of the deflection means;
A through-hole provided in a surface of the optical box facing the optical bench for pulling the connecting means out of the optical box;
A sealing member for sealing between the through hole and the outside air;
Have
The image is characterized in that the sealing member is inserted into a recess provided in the optical bench facing the through hole, and the sealing member is sandwiched between the optical box and the optical bench. Forming equipment.   The coupling unit that connects the driving unit of the deflecting unit and the connecting unit is provided on a surface of the deflecting unit facing the optical bench through the through hole of the substrate. The image forming apparatus according to 1. The sealing member, the formed annular surrounding the through hole, an image forming apparatus according to claim 1 or claim 2, characterized in that it is fixed to the optical box. The sealing member comprises a plurality of sealing members which are stacked together, the image forming apparatus according to any one of claims 1 to 3 wherein said connecting means is characterized in that it is clamped by the sealing member of the plurality of. Deflection means for converting a light beam generated from a light source into scanning light ;
An imaging means for imaging the scanning light on a photoconductor;
An optical box that houses the deflecting means and the imaging means ;
A lid for sealing the opening of the optical box ;
Control means disposed outside the optical box ;
An optical bench for fixing the optical box ;
Connection means for electrically connecting the control means and the drive means of the deflection means ;
A through-hole provided in a surface of the optical box facing the optical bench for pulling the connecting means out of the optical box ;
A sealing member for sealing between the through hole and the outside air ;
Have
The sealing member is composed of a plurality of sealing members stacked on each other, the connecting means is sandwiched between the plurality of sealing members, and the plurality of sealing members are sandwiched between the optical box and the optical bench. An image forming apparatus .

Images