JP5150145B2 - Lubricant coating apparatus and image forming apparatus equipped with the same - Google Patents

Description

  The present invention relates to a lubricant application device used in an image forming apparatus represented by a copying machine, a printer, a facsimile, and the like, and an image forming apparatus equipped with the same.

  An image carrier is provided in this type of image forming apparatus, and a toner image formed on the image forming surface is transferred to a medium. A technique is known in which the image forming surface is cleaned after transfer to remove residual toner, and a lubricant is applied to the image forming surface (see, for example, Patent Documents 1 and 2).

  Specifically, in this technique, the brush is provided so as to be able to contact and separate from the image forming surface, and a solid lubricant is installed on the back side of the brush. The lubricant is applied to the image forming surface via a brush to keep the surface friction coefficient of the image forming surface low.

JP 7-271142 A Japanese Patent Laid-Open No. 7-271262

However, in the above conventional technique, the brush and the solid lubricant are in contact with each other even when the brush is in contact with the image forming surface or when the brush is separated from the image forming surface. This has various problems.
Specifically, since the brush and the lubricant are always in contact with each other, for example, when the brush is rotating, the lubricant is scraped more than necessary, and the consumption of the lubricant becomes very large. On the other hand, when the brush is stopped, a load from the lubricant is always applied to the brush, and creep deformation of the brush occurs.

Thus, in the above-described conventional technology, no special consideration is given to the point where the brush and the lubricant are brought into contact only when necessary.
In order to solve this problem, it is necessary to pay attention to the particle size of the lubricant. This is because, when lubricants having various particle sizes of large and small are applied to the image forming surface, it affects the uniformity of the image forming surface.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and provide a lubricant application device that does not always contact a brush and a solid lubricant, and an image forming apparatus equipped with the lubricant application device.

To achieve the above object, a first invention is directed to an application member engaged with a torsion spring in a state where it can be pressed against and separated from an image forming surface of an image carrier having a toner image, and an application member. And a solid lubricating member that imparts lubricity to the image forming surface via the coating member. When the coating member is pressed against the image forming surface, the solid lubricating member is applied. When the application member is separated from the image forming surface while being separated from the member, the solid lubricating member is brought into contact with the application member.

According to the first invention, the image forming surface of the image carrier is given lubricity by the solid lubricating member via the coating member. Here, only when the application member is separated from the image carrier, the solid lubricating member and the application member come into contact with each other. That is, when the application member is separated from the image forming surface, the solid lubricating member is brought into contact with the application member, and the lubricant is not supplied to the image forming surface. On the other hand, when the application member is brought into pressure contact with the image forming surface, the solid lubricating member is separated from the application member, and the lubricant is supplied to the image forming surface. Therefore, as compared with the case where the solid lubricating member and the coating member are always in contact with each other, the consumption of the solid lubricating member is reduced. As a result, the coating device can be downsized and the manufacturing cost can be reduced. Longer service life can be achieved.
In addition, when the coating member is brought into pressure contact with the image forming surface, the lubricant is not applied to the image forming surface with its particle size as compared with the case where the solid lubricating member and the coating member are brought into contact with each other. An image forming surface can be obtained.

Particularly in the first aspect of the invention, the application member is moved away from the image forming surface by moving the application member in a direction according to the biasing force of the torsion spring, and the application member is moved in a direction against the biasing force of the torsion spring. And a coating member operating mechanism that presses the coating member against the image forming surface. The coating member also has a function of cleaning the image forming surface. When the application member moves the application member in a direction against the biasing force of the torsion spring to bring the application member into contact with the image forming surface, the toner image formed on the image forming surface is transferred to the medium. The member operating mechanism moves the application member in a direction according to the urging force of the torsion spring to separate the application member from the image forming surface.
In addition to the above action, the solid lubricant is in contact with the coating member only when the coating member is separated from the image forming surface. Can be applied to the surface.

The second invention further comprises a housing having an opening facing the image forming surface in the configuration of the first and second inventions, and a housing in which an application member and a solid lubricating member are disposed. The member is configured to be capable of being pressed against and separated from the image forming surface at the opening, and the solid lubricating member is disposed on the back surface of the application member opposite to the opening.
According to the second invention, in addition to the operation of the first invention, the application member and the solid lubrication member are disposed in the housing, and the solid lubrication member is separated from the opening on the back side of the application member. Are arranged. Therefore, if the arrangement space for the solid lubricating member is ensured, the solid lubricating member can be installed without greatly changing the existing coating apparatus. This also contributes to downsizing of the coating apparatus.

A third aspect of the invention is an image forming apparatus equipped with the first or second lubricant application device.
According to the third aspect of the invention, in addition to the effects of the first and second aspects, the selected lubricant is applied to the image forming surface and a good image is obtained. As a result, the reliability of the image forming apparatus is improved. Contribute to.

  According to the present invention, it is possible to provide a lubricant coating device that can achieve downsizing of the coating device, a reduction in manufacturing cost, and a long life, and an image forming apparatus equipped with the lubricant coating device.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the printer 1 in this embodiment, in which the right side corresponds to the front side of the printer 1 and the left side corresponds to the back side.
An image forming unit 3 having a photosensitive drum 4 is built in the apparatus main body 2. A photosensitive layer made of, for example, amorphous silicon is formed on the outer peripheral surface of the drum 4, and the drum 4 rotates counterclockwise in FIG. A series of operations with the primary transfer of the toner image is performed.

Specifically, a charger 6 is provided around the drum 4 in the vicinity of the upper position thereof, and the outer peripheral surface of the drum 4 is charged by the charger 6. Then, in a state where the drum 4 is charged, scanning light is irradiated from the laser scanning unit 8 toward the outer peripheral surface thereof.
For example, the unit 8 reflects laser light while rotating a polygon mirror at a high speed, and reflects the laser light scanned in the axial direction of the drum 4 with a plane mirror to expose the outer peripheral surface of the drum 4. As a result, an electrostatic latent image is formed on the outer peripheral surface of the drum 4.

  Further, the developing unit 10 is disposed downstream of the scanning light irradiation position in the rotation direction of the drum 4. Specifically, the unit 10 is disposed in the vicinity of the outer peripheral surface of the drum 4 and develops an electrostatic latent image by a rotary method using toners of four colors (for example, magenta, cyan, yellow, and black). . That is, the unit 10 is also configured to be rotatable, and has four developing devices 10a, 10b, 10c, and 10d that are classified according to the respective colors in the rotation direction.

  Each of the developing devices 10a to 10d contains toner, and each of the developing devices 10a to 10d is provided with developing rollers 11a to 11d that rotate while carrying the toner on the outer peripheral surface thereof. Yes. Further, a toner container 9 is built in an appropriate position on the front side of the printer 1, and each developing device 10 a to 10 d is supplied with toner for each color through a supply pipe 13.

  In the unit 10, with the rotation, one of the developing devices 10 a to 10 d corresponding to the color to be developed is stopped in a state where it faces the outer peripheral surface of the drum 4. On the other hand, in each developing device 10a to 10d, each developing roller 11a to 11d rotates while carrying a toner thin layer on its outer peripheral surface, and each roller 11a to 11d has a developing bias composed of an AC component and a DC component. A voltage is applied. As a result, the toner carried on each of the rollers 11a to 11d moves toward the electrostatic latent image on the drum 4, and the electrostatic latent image is developed with toners of different colors.

  A rubbing member 14 and a cleaning member 16 are disposed around the drum 4 along the outer peripheral surface thereof. Specifically, the rubbing member 14 and the cleaning member 16 are respectively disposed upstream of the charger 6 as viewed in the rotation direction of the drum 4. The rubbing member 14 polishes the outer peripheral surface of the drum 4 after the toner image is primarily transferred, and removes oxidation products adhering to the photoreceptor layer. On the other hand, the cleaning member 16 removes the toner remaining on the outer peripheral surface of the drum 4 and cleans the outer peripheral surface before the next image formation.

  On the other hand, an intermediate transfer unit 7 is disposed below the drum 4 and the toner container 9. The unit 7 includes an endless intermediate transfer belt (image carrier) 12, and the surface (image forming surface) thereof is disposed close to the outer peripheral surface of the drum 4. As the belt 12, for example, a belt in which both end portions of a dielectric resin sheet material are overlapped and joined to each other, or a seamless belt is used.

  The belt 12 is wound around a driving roller 18a and a tension roller 12a, and a primary transfer position with the drum 4 is provided between these rollers. Specifically, the roller 18a is disposed upstream of the primary transfer position in the circumferential direction of the belt 12, and the roller 12a is disposed downstream. An appropriate tension is applied to the latter roller 12a toward the belt 12 by a repulsive force of a spring (not shown), for example.

The belt 12 passes through a position in contact with the outer peripheral surface thereof in synchronization with the rotation of the drum 4 and travels in the circumferential direction. The toner image formed on the drum 4 is transferred from the outer peripheral surface to the surface of the belt 12. Primary transfer is performed.
A transfer portion 18 is formed in the vicinity of the drive roller 18a. The transfer unit 18 includes a roller 18b. The roller 18b rotates in pairs with the roller 18a across the belt 12, and a transfer nip is formed between the belt 12 and the roller 18b.

  Here, in the same figure, the conveyance direction of the sheet is indicated by an arrow. A paper cassette 24 is disposed in the lower part of the apparatus main body 2, and sheets are stored in the cassette 24 in a stacked state. A paper feed roller 26, a registration roller 28, a transfer unit 18 and a fixing unit 20 are arranged in this order on the downstream side of the cassette 24 in the paper transport direction. When the paper passes through the transfer unit 18, a full-color toner image for each page. Is secondarily transferred from the belt 12 to the paper.

  When an image is formed only on one side of the sheet, the sheet that has passed through the fixing unit 20 is discharged to the discharge tray 22 via the discharge roller 21. On the other hand, when images are formed on both sides of the sheet, the sheet that has passed through the fixing unit 20 is drawn back into the sheet reversing path 23 via the reversed discharge roller 21. One end of the path 23 is communicated between the paper feed roller 26 and the registration roller 28, and the paper in the path 23 is conveyed again toward the transfer unit 18.

Incidentally, a cleaning unit (lubricant coating device) 40 is installed in the vicinity of the transfer portion 18 of the present embodiment.
Specifically, the unit 40 is disposed so as to face the driving roller 18a of the intermediate transfer unit 7, and after the toner image on the belt 12 is secondarily transferred to the paper, it adheres to the belt 12. Residual toner and the like are removed.

  More specifically, as shown in FIGS. 2 and 3 in which the exterior cover of the apparatus main body 2 is omitted, the intermediate transfer unit 7 is exposed to the outside when the exterior cover is opened and the toner container 9 is removed. In this state, for example, when the user holds the handle portion (not shown) and lifts the unit 7 diagonally to the upper right, the cleaning unit 40 is also removed from the apparatus body 2 together with the unit 7.

  As shown in FIG. 4, the intermediate transfer unit 7 is provided with support portions that rotatably support both ends of the rollers 12 a and 18 a that are wound around the belt 12. On the other hand, as shown in FIG. 5, the cleaning unit 40 includes a roller-shaped fur brush (application member) 48, and the brush 48 can rotate while contacting the belt 12 at a position facing the roller 18a. The residual toner after the secondary transfer is electrically removed.

  Specifically, as shown in FIG. 6, the cleaning unit 40 includes a bottomed housing 42 that opens toward the belt 12, and image formation in which the opening 44 of the housing 42 is the surface of the belt 12. It is formed opposite to the surface 30. The housing 42 is gradually reduced in diameter from the opening 44 toward the bottomed portion, and a recovery spiral 58 is disposed in the bottomed portion.

The brush 48 described above is disposed in the vicinity of the opening 44, disposed substantially parallel to the axis of the drive roller 18 a, and both ends of the shaft 50 are disposed on a plate 68 positioned in the vicinity of the side surface of the housing 42. It is rotatably supported (FIGS. 8 and 9).
In this embodiment, a sweep roller 52 is provided in the housing 42. The roller 52 is disposed above the brush 48, is disposed substantially parallel to the axis of the brush 48, and both ends of the shaft 53 are rotatably supported by the plate 68.

The sweep roller 52 is configured to be able to apply a voltage, and a voltage is also applied to the brush 48. As a result, the roller 52 frictionally contacts the brush 48 and electrically adsorbs the residual toner attached to the brush 48.
On the other hand, the shaft 53 of the roller 52 and the shaft 50 of the brush 48 are engaged by a torsion spring 69 (FIG. 9), and the spring 69 biases the brush 48 in a direction in which the brush 48 is separated from the image forming surface 30. doing.

  Returning again to FIG. 6, a support base 56 is disposed between the brush 48 and the collection spiral 58, and a blade 54 is provided on the support base 56. The blade 54 of this embodiment is disposed so as to be in contact with the sweep roller 52 and scrapes off the residual toner adsorbed by contacting the outer peripheral surface of the roller 52. Then, the scraped toner is collected in the collection spiral 58.

  In this embodiment, a solid lubricating member 66 is provided below the blade 54. The lubricating member 66 is formed in a rectangular parallelepiped shape, is disposed substantially parallel to the axis of the brush 48, and is held on the support base 56 on the back surface of the brush 48. That is, the lubricating member 66 of the present embodiment is disposed on the opposite side of the opening 44 with the brush 48 interposed therebetween. For example, it contains zinc stearate and is configured to come into contact with the brush 48 to impart lubricity to the image forming surface 30.

  Here, the plate 68 described above is connected to a brush operating mechanism (application member operating mechanism) 70. Specifically, as shown in FIGS. 7 and 8, the operating mechanism 70 has a shaft 74 disposed above the sweep roller 52, and both ends of the shaft 74 are at one end of the side surface of the housing 42. The other end is fitted on the upper side of the plate 76. In addition, a pressing piece is fixed to the shaft 74, and the pressing piece is configured to be able to contact the upper end side of the plate 68.

On the other hand, the operating mechanism 70 has an arm 78, and this arm 78 is rotatably supported below the center of gravity of the plate 76. The arm 78 extends toward the solenoid 80, and the solenoid 80 is fixed to the apparatus main body 2.
When the image forming surface 30 is cleaned, the solenoid 80 is excited by a signal from a controller (not shown), and the arm 78 moves toward the solenoid 80.

At the same time, the plate 76 rotates clockwise as shown in FIG. 8 from the state of FIG. 9, and the pressing piece rotates the plate 68 counterclockwise against the biasing force of the torsion spring 69. As a result, the brush 48 moves toward the belt 12 and presses against the image forming surface 30, and residual toner on the image forming surface 30 adheres to the brush 48.
Next, the residual toner adhering to the brush 48 is attracted to the sweep roller 52, and the residual toner adsorbed to the roller 52 is scraped off and collected by the blade 54. As the brush 48 moves, the front end of the lubricating member 66 moves away from the brush 48 (FIG. 6).

  On the other hand, when the toner image on the image forming surface 30 is secondarily transferred to the sheet, the solenoid 80 is demagnetized and the plate 68 is rotated clockwise by the biasing force of the torsion spring 69. As a result, the brush 48 moves toward the collection spiral 58 and is separated from the image forming surface 30. As the brush 48 moves, the front end of the lubricating member 66 comes into contact with the brush 48 at the surface instead of the ridge line edge (FIG. 10).

  In the printer 1 equipped with the above-described cleaning unit 40, the sheets are fed one by one from the cassette 24, and the sheets reach the registration rollers 28. The roller 28 temporarily stops in a state where the sheet is held, and then feeds the sheet to the transfer unit 18 at a timing synchronized with the running of the belt 12 while correcting the inclination and skew of the sheet.

  Further, the toner carried on each of the rollers 11 a to 11 d of the developing unit 10 moves toward the electrostatic latent image on the drum 4 and forms a toner image on the outer peripheral surface of the drum 4. This toner image is primarily transferred from the outer peripheral surface of the drum 4 to the surface of the belt 12 and synthesized. Subsequently, the full color toner image in units of one page transferred and synthesized on the belt 12 is secondarily transferred onto a sheet by the transfer unit 18. Thereafter, the toner remaining on the surface of the belt 12 is removed by the cleaning unit 40.

The sheet on which the toner image has been secondarily transferred is sent toward the fixing unit 20 and is heated and pressed by passing through the nip between the heat roller 20a and the pressure roller 20b to fix the toner image. Next, the sheet from the fixing unit 20 is discharged to the tray 22.
When double-sided printing is performed in contrast to this single-sided printing, a part of the sheet from the fixing unit 20 protrudes onto the tray 22 and then is reversely rotated to be pulled back into the sheet reversing path 23. This sheet is sent again toward the transfer section 18 via the registration roller 28. In this case, the toner image is secondarily transferred onto the side of the paper that has not been printed.

As described above, the present invention focuses on the fact that the solid lubricating member 66 and the brush 48 are not always brought into contact with each other, but are brought into contact only when necessary.
In this embodiment, the image forming surface 30 of the belt 12 is provided with lubricity by the solid lubricating member 66 via the brush 48. Here, only when the brush 48 is separated from the belt 12, the lubricating member 66 and the brush 48 come into contact with each other.

  That is, when the brush 48 is separated from the image forming surface 30, the lubricating member 66 is brought into contact with the brush 48 and the lubricant is not supplied to the image forming surface 30. On the other hand, when the brush 48 is brought into pressure contact with the image forming surface 30, the lubricating member 66 is separated from the brush 48 and the lubricant is supplied to the image forming surface 30. Therefore, the consumption of the lubricating member 66 is reduced as compared with the case where the lubricating member 66 and the brush 48 are always in contact. As a result, the lubrication member 66 can be reduced in size, the unit 40 can be reduced in size and the manufacturing cost can be reduced, and maintenance of the brush 48 and the lubrication member 66 can be freed, resulting in a long life of the unit 40. Can also be achieved.

  In addition, when the brush 48 is brought into pressure contact with the image forming surface 30, the lubricant is not applied to the image forming surface 30 with its particle size as compared with the case where the lubricating member 66 and the brush 48 are brought into contact with each other. For example, among the particles of the lubricant, those having a large particle size fall downward as the brush 48 rotates, and only those having a small particle size are selected and applied to the image forming surface 30 to be uniformized. . Therefore, a good image forming surface can be obtained.

Further, since the lubricating member 66 contacts the brush 48 only when the brush 48 is separated from the image forming surface 30, the lubricant after the particle size has been reliably selected can be applied to the image forming surface. Become.
Further, since there is no need to provide a mechanism for separately operating the lubricating member 66 in addition to the operating mechanism 70, this point also contributes to the downsizing of the unit 40, the reduction of the manufacturing cost, and the extension of the service life.

  Furthermore, the brush 48 and the lubricating member 66 are disposed in the housing 42, and the lubricating member 66 is disposed away from the opening 44 on the back side of the brush 48. Therefore, if the arrangement space for the lubricating member 66 is secured in the housing 42, the solid lubricating member can be installed without greatly changing the existing cleaning unit. This also reduces the size of the unit 40 and the like. Contribute.

  Further, even if the lubricating member 66 is a soft lubricant, it is not applied to the image forming surface 30 as a fine aggregate from the brush 48, and the selected lubricant is applied to the image forming surface 30. The Specifically, variations in the hardness and particle size of the lubricant are avoided, and only the lubricant having the optimum hardness and particle size is applied to the image forming surface 30. As a result, a good image is obtained and the reliability of the printer 1 is improved. Contributes to improvement.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims.
For example, in the above embodiment, the blade 54 is in contact with the sweep roller 52. However, if the roller 52 is not provided, the blade may directly contact the brush 48. It is not limited to fur brushes.

  In the above embodiment, an example in which the image forming apparatus is embodied in the printer 1 having the intermediate transfer belt is shown. However, the cleaning apparatus of the present invention is a printer that does not have the belt, that is, a photosensitive member having residual toner. It may be an apparatus for cleaning the image forming surface of the drum, and is naturally applicable to a multifunction machine, a copying machine, a facsimile machine, and the like.

1 is a schematic configuration diagram of a printer in the present embodiment. FIG. 2 is a perspective view illustrating a state where an intermediate transfer unit is attached to the apparatus main body of FIG. 1. FIG. 2 is a perspective view showing a state where an intermediate transfer unit and a cleaning unit are removed from the apparatus main body of FIG. 1. FIG. 2 is a perspective view of the intermediate transfer unit in FIG. 1. It is a perspective view of the cleaning unit of FIG. It is sectional drawing of the cleaning unit of FIG. FIG. 6 is a perspective view of the cleaning unit of FIG. 5. FIG. 8 is an enlarged view of FIG. 7, illustrating a pressure contact operation. It is a figure explaining the separation | spacing operation | movement in the unit of FIG. FIG. 10 is a cross-sectional view of the unit of FIG. 9.

Explanation of symbols

1 Printer (image forming device)
7 Intermediate transfer unit 12 Intermediate transfer belt (image carrier)
30 Image forming surface 40 Cleaning unit (lubricant coating device)
42 Housing 44 Opening 48 Brush (Coating Member)
66 Solid Lubrication Member 70 Brush Actuation Mechanism (Coating Member Actuation Mechanism)

Claims (3)

Residual toner that is engaged with a torsion spring in a state where it can be pressed against and separated from an image forming surface of an image carrier having a toner image, and is coated with a lubricant and adhered to the image forming surface An application member that also has a function of cleaning while rotating according to the traveling direction of the image forming surface ,
It is configured to be able to come into contact with and separate from the application member, and when contacted on the downstream side of the contact position of the sweep roller that adsorbs the residual toner adhering to the application member when viewed in the rotation direction of the application member. A solid lubricating member that imparts lubricity to the image forming surface through the coating member;
The application member is moved away from the image forming surface by moving the application member in a direction according to the urging force of the torsion spring, and the application member is moved in a direction against the urging force of the torsion spring. An application member operating mechanism that presses the application member against the image forming surface.
When the coating member is pressed against the image forming surface, the solid lubricating member is separated from the coating member, while when the coating member is separated from the image forming surface, the solid lubricating member is Contacting the application member,
Wherein when cleaning the image forming surface, while contacting the coating member by moving the application member in a direction in which the coating member actuating mechanism is anti to the biasing force of the torsion spring to the image forming surface, wherein When the toner image formed on the image forming surface is transferred to a medium, the application member operating mechanism moves the application member in a direction according to the urging force of the torsion spring, thereby moving the application member to the image forming surface. A lubricant application device characterized in that the lubricant application device is separated from the device. The lubricant application device according to claim 1,
A housing that has an opening facing the image forming surface and in which the coating member and the solid lubricating member are disposed;
The application member is configured to be capable of being pressed against and separated from the image forming surface at the opening, and the solid lubricating member is disposed on the back surface of the application member opposite to the opening. A lubricant application device characterized by comprising:   An image forming apparatus comprising the lubricant application device according to claim 1.

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