TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus including an optical unit that condenses an emitted light beam on a scanning surface and performs linear scanning.
2. Description of the Related Art Conventionally, a laser printer, for example, has been widely used as an image forming apparatus including an optical unit that focuses and scans a light beam on a scanning surface. In a laser printer, a photosensitive drum is exposed by an optical unit to form a latent image corresponding to characters and image information, and is visualized as a toner image by a developing device. After that, the image is transferred onto a recording sheet by a transfer unit and fixed, thereby performing printing. In this case, since the untransferred toner exists on the photosensitive drum after the transfer, the toner is removed by the cleaner. Conventionally, an optical unit in such a laser printer mainly scans a light beam using a polygon mirror.
Here, FIG. 6 shows a schematic configuration diagram of an optical unit using a conventional polygon mirror. The laser light emitted from the semiconductor laser of the optical unit 11 shown in FIG. 6 is incident on the rotatable polygon mirror 15 via the collimator lens 13 and the cylindrical lens 14 and is reflected. The laser light reflected by the polygon mirror 15 is condensed on the photosensitive drum 18 via the fθ lens 16 to perform a linear scan.
In the optical unit 11, the size of the apparatus is reduced so that the optical unit 11 is housed in a predetermined space, and the positions of the optical unit 11 and the photosensitive drum 18 are limited in order to effectively use the space in the apparatus. Often done. In that case, as shown in the schematic configuration diagram of the optical unit in FIG. 5, a plurality of reflection mirrors 20a and 20b are arranged on the optical axis from the polygon mirror, and the optical axis is changed to reach the photosensitive drum 18. Is configured. The reflection mirrors 20a and 20b are fixed with both ends in the longitudinal direction supported by the frame of the optical unit.
FIG. 7 is a schematic configuration diagram of a conventional image forming apparatus that forms an image by irradiating such light. In such an image forming apparatus, a high-quality image cannot be recorded if dust or dust adheres to the optical unit. Therefore, conventionally, in an electrophotographic system or the like, an optical unit such as a light source and a lens is hermetically sealed in a case to form an optical unit 11, and an emission opening in which a dustproof glass 17 is attached to the unit is provided. Light is emitted from the section.
[Problems to be solved by the invention]
However, since the surface of the dust-proof glass 17 is exposed by the apparatus 1, the paper dust is scattered due to the conveyance of the recording paper, the toner is scattered when the toner is supplied to the developing device, and the residual toner on the photosensitive drum 18 by the cleaner is removed. Dust and dust may adhere to the surface of the dust-proof glass 17 due to scattering of toner during cleaning. Normally, intrusion of impurities such as toner and paper dust is prevented by the shape of a cover or a frame. However, when the toner or paper dust adheres to the dust-proof glass 17, a laser beam emitted from the dust-proof glass 17 is used. Is partially shielded from light, which causes deterioration of a printed image and the like, which affects optical characteristics. In particular, when the optical unit 11 is provided below the apparatus main body and the emission opening is opened upward, there is a strong possibility that dust adheres to the dust-proof glass. Therefore, conventionally, in the case of maintenance and inspection of the apparatus, the dustproof glass 17 and the reflection mirror 20 have to be cleaned at last, and this operation is very troublesome.
The present invention has been made in view of the above problems, and has a simple configuration, in which a shielding member that shields the dust-proof glass in conjunction with the cartridge replacement operation is provided, and the shielding member cleans the dust-proof glass 17. It is another object of the present invention to improve optical characteristics in scanning of a light beam.
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes an optical unit having a light source and a dustproof transparent member that transmits light emitted from the light source, and irradiates the photosensitive member with light emitted from the light source to form an image. The image forming apparatus to be formed is characterized by having movable shielding means for shielding the dust-proof transparent member, and cleaning means provided on the shielding means for cleaning the dust-proof transparent member.
The shielding means is moved by opening and closing a door of the apparatus, and the door is opened and closed when the process cartridge is attached and detached.
The image forming apparatus is a color image forming apparatus for superimposing images of a plurality of colors, wherein one optical unit has a plurality of dustproof transparent members.
Further, the optical unit is located below the image forming means and irradiates light to the image forming apparatus above.
According to the above configuration, the dustproof transparent member provided on the optical unit is shielded and cleaned at the same time as the normal operation of the image forming apparatus such as opening the door of the apparatus for replacing the process cartridge. become. This is effective even in a case where a plurality of dustproof members are provided in accordance with the number of drums in a color image forming unit including a plurality of drums.
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment according to the present invention will be described in detail with reference to the drawings. Members corresponding to the members described with reference to FIGS. 5 to 7 are denoted by the same reference numerals, and detailed description is omitted.
FIG. 1 is a schematic front view of an image forming apparatus having an optical component cleaning mechanism according to a first embodiment of the present invention, and FIG. 2 is a top view showing the configuration of the cleaning mechanism. Here, as the order of the description, the overall configuration of the image forming apparatus according to the present invention will be described, and then the configuration of the optical component cleaning mechanism will be described.
The configuration of the image forming apparatus 2 shown in FIG. 1 is roughly divided into an image forming section, a sheet feeding / conveying section, and a fixing section, and the image forming section is located in the front view of FIG. . The paper feed unit is located from the lower right hand side to the upper right hand side of the front view, and the fixing unit is located at the uppermost right hand side. As shown in FIG. 1B, a part extending from a part of the conveying unit to the fixing unit is collectively provided in a block unit that opens and closes from the main body. Can be processed.
First, the image forming unit will be described. As an image forming procedure, an optical image based on image information of the optical unit 11 described later is irradiated to form an image of a developer (hereinafter, referred to as “toner”) on a photosensitive drum 18 as an image carrier. At this time, an image forming apparatus that forms an image in full color includes a plurality of image carriers on which these image forming processes are performed, and converts each color image of a cyan image, a magenta image, a yellow image, and a black image into each image. A full-color image is formed by synchronizing and transferring each color image to a sheet material at a transfer position of each image carrier at a transfer position of each image carrier.
In FIG. 2, the image forming unit is formed as a process cartridge 10 for each color. Here, the photosensitive drum 18, the charging unit 19, the developing unit 30, and the cleaning unit 31 are formed into a cartridge. Since the process cartridges of the respective colors have substantially the same configuration, numbers are assigned only to the process cartridge 10 at the left end, and the description will be added below.
The configuration of the optical unit 11 is as follows. A laser emitting unit (not shown) emits a laser beam, and a laser is emitted through a dustproof glass 17 in the generatrix direction of a photosensitive drum 18 provided above the optical unit 11 by the rotation of the polygon mirror 15. Deflection scanning is performed to form a latent image on the drum surface that has been charged by the charger 19 in advance. This latent image is developed as a toner image by a developing unit 30 provided around the photosensitive drum 18 and is transferred by applying a voltage to a transfer belt 12 supported by a plurality of rollers as transfer means. . The toner remaining on the drum surface after the image transfer is removed by the cleaning device 31. Thereafter, each color image such as a cyan image, a magenta image, a yellow image, and a black image is sequentially formed on the transfer belt 12 in synchronization with each other to form a full-color image, and a voltage is applied again on the secondary transfer roller pair 32 to perform recording. The image is transferred to a sheet as a medium.
Next, the paper feeder will be described. In the image forming apparatus shown in FIG. 2, the sheet feeding / conveying unit includes a cassette 3 on which sheets S as recording media are stacked, a pickup roller 4, a pair of registration rollers 5, and the like. First, the sheet S fed one by one from the sheet stacking unit in the cassette 3 by the pickup roller 4 once abuts the nip of the registration roller pair 5 that is stopped adjacent to the sheet conveyance upstream of the image forming unit. . At that time, the leading edge of the sheet is detected by a sheet detecting sensor (not shown) arranged near the upstream of the pair of registration rollers. The conveying roller upstream of the roller pair 5 is stopped. As a result, the leading edge of the sheet is made parallel to the nip line of the registration roller at the waist of the sheet, and the skew of the sheet material is corrected. Thereafter, the registration roller and the conveyance roller are driven in synchronization with the above-described image formation of each color on the transfer belt 12, and the transfer of the image to the sheet and the alignment are performed on the secondary transfer roller pair 32. At this time, the peripheral speed of the registration roller is set substantially equal to the image forming speed.
Finally, the sheet on which the full-color transfer toner image is formed is conveyed to the fixing unit. The fixing unit includes a driving roller 40 and a fixing roller 41 having a built-in heater, and applies heat and pressure to a passing sheet to fix the transferred toner image. The sheet is conveyed by a pair of discharge rollers 43 and is discharged to a discharge unit 44.
｛Cleaning mechanism for optical parts｝
Next, a cleaning mechanism of the dustproof glass 17 in the optical unit 11 will be described with reference to FIGS. The optical unit 11 cannot record a high-quality image if dust or dirt adheres to the optical unit. In particular, in the configuration shown in the figure, the optical means is located below the image forming apparatus, and the toner particles scattered due to the replacement operation of the process cartridge easily adhere to the dustproof glass. Therefore, an optical unit 11 is configured by sealing optical components such as a polygon mirror 15 and a lens in a case, and an emission opening to which a dustproof glass 17 is attached is provided in the unit, and light is radiated from the opening. ing. Further, on the optical unit 11 in the main body of the apparatus 2, a cleaning member for cleaning the dustproof glass 17 along the optical case is provided. This cleaning member also functions as a shielding plate for shielding the dustproof glass when the process cartridge is replaced. Accordingly, it is possible to prevent scattered toner particles from adhering due to a cartridge replacement operation which is likely to cause contamination of the dustproof glass 17.
FIG. 2 is a top view of the optical unit 11 and the cleaning member according to the first embodiment. The cleaning member is an elongated cleaning plate 50a, 50b, 50c, 50d arranged so as to cover the slit-shaped dustproof glass 17 of each color by moving along the optical case, and each cleaning plate is disposed in the longitudinal direction. It comprises support arms 51a and 51b supported at both ends and a shaft 53 connecting the support arms 51a and 51b. Further, a brush serving as a cleaning unit for the dustproof glass 17 is attached to the cleaning plate 50 toward the dustproof glass 17.
On the other hand, the transport / fixing block shown on the right hand side in the front view of FIG. 1B is opened so that the processing can be performed when a process cartridge of each color is exchanged or a sheet is jammed in the paper feed transport unit. It has become. At both ends of the shaft 53, transmission arms 52a and 52b are mounted so as to be slidable and lockable within a predetermined range with respect to the shaft 53, and the ends of the transmission arms 52a and 52b It is supported by a rotation shaft 55 so as to be rotatable in conjunction with opening and closing of the fixing block.
In the above configuration, when the transport / fixing block is opened, first, the transmission arms 52a and 52b move in a direction away from the optical unit 11 while rotating with respect to the transport / fixing block. That is, since the shaft 53 is pulled in the direction of arrow A shown in FIG. 2B, the support arms 51a and 51b connected to the shaft 53 are also pulled in the same direction. As a result, the cleaning plate 50 supported by the support arms 51a and 51b moves in a direction to shield the dustproof glass 17, and the brush provided on the cleaning plate 50 cleans the dustproof glass. At this time, the cleaning plate is configured to have such a positional relationship that the dust-proof glass 17 is completely shielded when the transport / fixing block is completely opened.
Therefore, the dirt on the dust-proof glass 17 is automatically cleaned every time the transport / fixing block is opened when the process cartridge 10 is attached or detached by the above-described process. Deterioration is prevented. At the same time, since the dust-proof glass 17 is shielded, it is possible to prevent the scattered toner caused by attaching and detaching the process cartridge 10 from adhering to the dust-proof glass.
As described above, according to the embodiment described in detail, it is understood that the dustproof glass 17 can be cleaned and the dustproof glass 17 can be shielded at the same time as the process cartridge 10 is replaced with a simple configuration.
The dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
For example, in this embodiment, the optical unit is mounted below and irradiates the laser light toward the upper process unit, but conversely, from the optical unit mounted above to the lower process unit. This is also true in a configuration in which laser irradiation is performed.
With a simple configuration, the means for cleaning and shielding the dustproof glass 17 when replacing the process cartridge is not limited to the first embodiment. Hereinafter, a second embodiment according to the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Further, since the overall configuration of the apparatus main body is the same as that of the first embodiment, the description is omitted.
Also in the second embodiment, a cleaning member for cleaning the dustproof glass 17 along the optical case is provided on the optical unit 11. FIG. 3 is a top view of the optical unit 11 and the cleaning member according to the second embodiment. FIG. 4 is a perspective view of the optical unit 11 and the cleaning member according to the second embodiment.
The cleaning member is an elongated cleaning plate 50a, 50b, 50c, 50d arranged so as to cover the slit-shaped dustproof glass 17 of each color by moving along the optical case, and each cleaning plate is disposed in the longitudinal direction. Support arms 61a and 61b are supported at both ends, and turning arms 62a and 62b are provided to support the supporting arms 61a and 61b so as to be rotatable around a turning shaft 68. Further, a brush serving as a cleaning unit for the dustproof glass 17 is attached to the cleaning plate 50 toward the dustproof glass 17. Further, on the optical unit, there are provided rotating shafts 63a and 63b of the rotating arm and a stopper 64, and at the end of the rotating arm b located on the back side of the apparatus main body, the back end of the cassette 3 is provided. A locking shaft 65 having a length engaging with the side is provided. The rotating arms 62a and 62b are urged around the rotating shafts 63a and 63b in the direction of arrow B shown in FIG. 4 by urging means such as a torsion coil spring (not shown).
On the other hand, the cassette 3 arranged at the lower part of the front view of FIG. 1 can be stored and pulled out freely in the front-rear direction in FIG. This configuration is the same in the second embodiment.
Under the above configuration, when the cassette 3 is stored and pulled out in FIG. 4, first, when the cassette 3 is pulled out, the rotating arm is rotatable around the rotating shaft 63b, so that it is rotated in the direction of arrow B in FIG. I do. At this time, since the cassette 3 is pulled out, the locking shaft 65 does not interfere with the rear end side of the cassette 3, so that the rotating arm 62 b rotates to a position where it is locked by the stopper 64.
The rotation angle and length of the rotation arm 62b are configured such that the cleaning plate 50 supported by the rotation shaft 68 just shields the dustproof glass when the rotation arm 62b is abutted against the stopper 64. Therefore, at this time, the brush on the cleaning plate 50 passes over the dustproof glass, and as a result, the dustproof glass is cleaned. At the same time, the dustproof glass can be shielded.
When the front door is closed, the locking shaft 65 is locked to the rear end side of the cassette 3 to be urged in the direction opposite to the arrow B shown in FIG. Passes over the dust-proof glass 17 through the reverse process. The locking shaft 65 is arranged so that the cleaning plate 50 does not shield the dustproof glass 17 when the cassette 3 is completely stored.
Therefore, it can be understood that the dirt on the dust-proof glass 17 is automatically cleaned and the dust-proof glass is shielded every time the process cartridge is exchanged through the above process.
As described above, similarly to the first embodiment, it is understood that cleaning and shielding of the dustproof glass 17 can be performed with a simple configuration in the normal operation of the image forming apparatus.
The scope of the present invention is not limited to the second embodiment unless otherwise specified. For example, a brush is used to clean the dustproof glass 17, but a pad member may be used.
【The invention's effect】
As described above, according to the present invention, in an image forming apparatus that forms an image by irradiating light, the cleaning member is optically coupled with the opening operation of the opening of the image forming apparatus when the process cartridge is replaced. It is possible to shield and clean the dust-proof transparent member on the unit with a simple configuration. Thus, the dust-proof glass 17 can be cleaned in conjunction with frequent operations such as opening and closing of the front door, and the frequency of cleaning the dust-proof glass 17 can be increased. Further, when the process cartridge is attached or detached, the dust-proof glass can be reliably shielded. As a result, it is possible to provide an image forming apparatus that automatically improves optical characteristics in light beam scanning with a simple configuration without the user's awareness. In addition, the time and effort for cleaning the dustproof glass 17 at the time of maintenance and inspection of the apparatus can be omitted, and the effect of improving the efficiency of the maintenance work of the apparatus can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic front view of an image forming apparatus according to a first embodiment of the present invention; FIG. 2 is a top view of an optical unit and a cleaning member according to the first embodiment of the present invention; FIG. 4 is a top view of an optical unit and a cleaning member according to a second embodiment of the present invention. FIG. 4 is a perspective view of an optical unit and a cleaning member according to a second embodiment of the present invention. FIG. FIG. 6 is a schematic configuration diagram of an optical unit using a conventional polygon mirror. FIG. 7 is a schematic configuration diagram of an image forming apparatus having a conventional optical unit.
DESCRIPTION OF SYMBOLS 1 Conventional image forming apparatus 2 Image forming apparatus 3 according to the present invention 3 Cassette 4 Pickup roller 5 Registration roller 10 Process cartridge 11 Optical unit 12 Transfer belt 15 Polygon motor 17 Dustproof glass 18 Photosensitive drum 32 Secondary transfer roller pair 40 Drive roller 41 Fixing roller 50 Cleaning plate