JP3720522B2 - Electrophotographic image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a laser beam printer. More specifically, a plurality of developing cartridges are used to form a toner image for each color on an electrophotographic photosensitive drum, and a plurality of intermediate transfer members are formed. The present invention relates to an electrophotographic image forming apparatus that forms a color toner image and forms a color image on a recording material.
[0002]
[Problems to be solved by the invention]
The present invention is a further development of the prior art described below.
[0003]
An object of the present invention is to provide an electrophotographic image forming apparatus having a developing device carrying a developing cartridge by a developing rotary, and an electronic device having a mechanical brake mechanism that can fix the developing rotary without using electric power when replacing the developing cartridge. A photographic image forming apparatus is provided.
[0004]
[Means for Solving the Problems]
The first invention according to the present application is In an electrophotographic image forming apparatus that forms an image on a recording medium, a drive motor; An electrophotographic photosensitive drum, a rotatable developing rotary, a mounting portion for detachably mounting a developing cartridge for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, and the developing rotary of To move the developer cartridge provided on the outer periphery Said Drive motor From of A development rotary having a rotary gear for receiving a driving force; An opening for mounting the developing cartridge to the mounting portion, an opening / closing member capable of taking an open position for opening the opening and a closed position for closing the opening; It is provided rotatably in the main body of the electrophotographic image forming apparatus. The A first gear meshing with the rotary gear, and a rotatable on the apparatus main body. The A second gear that meshes with the first gear; a third gear that meshes with the first gear; and a first roller that rotates integrally with the second gear, the diameter of the tip circle of the second gear. A first roller having a larger diameter, a second roller rotating integrally with the third gear, the second roller having a diameter larger than the diameter of the tip circle of the third gear, and the device Provided in the body Further, the third gear and the second roller are rotatably supported and moved in conjunction with the opening / closing member. When the opening / closing member is located at the open position, the second roller is moved to the first roller. In When the contact position to be contacted and the opening / closing member are located at the closed position, the second roller is moved to the first roller. From An electrophotographic apparatus comprising: a swinging member that can be separated; and a biasing member that biases the swinging member in a direction in which the second roller contacts the first roller. An image forming apparatus.
[0005]
The second invention according to the present application is Further, the apparatus main body includes a fixing member in which the first gear, the first roller, and the second gear are rotatably provided. The electrophotographic image forming apparatus according to the first aspect of the present invention.
[0006]
The third invention related to this application is The fixing member, the swinging member supported by the fixing member so as to be swingable, and the biasing member are configured as an integral unit and are fixed to the apparatus main body. An electrophotographic image forming apparatus according to a second aspect of the present invention.
[0007]
The fourth invention related to this application is In an electrophotographic image forming apparatus that forms an image on a recording medium, a drive motor; An electrophotographic photosensitive drum, a rotatable developing rotary, a mounting portion for detachably mounting a developing cartridge for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, and the developing rotary of To move the developer cartridge provided on the outer periphery Said Drive motor From of A development rotary having a rotary gear for receiving a driving force; An opening for mounting the developing cartridge to the mounting portion, an opening / closing member capable of taking an open position for opening the opening and a closed position for closing the opening, and movement in conjunction with the opening / closing member A meshing member that engages with the rotary gear when the open / close member is in the open position; Development rotary rotation Do And when the opening / closing member is located at the closed position, the engagement with the rotary gear is released, Development rotary rotation Do An electrophotographic image forming apparatus characterized by having a release position that permits the engagement, and a meshing member that can take the position.
[0008]
The fifth invention related to this application is The meshing member is a projection that meshes with the rotary gear. An electrophotographic image forming apparatus according to a fourth aspect of the present invention.
[0009]
The sixth invention according to this application is The electrophotographic image forming apparatus includes a biasing member for biasing the meshing member to the meshing position when the opening / closing member is in the open position. An electrophotographic image forming apparatus according to the fifth invention.
[0016]
[Prior art]
Conventionally, toner images are formed one by one on an electrophotographic photosensitive drum using a plurality of developing cartridges, the toner images are sequentially transferred to an intermediate transfer member, and a plurality of color toner images are superimposed on the intermediate transfer member to form an intermediate image. In an electrophotographic image forming apparatus that forms a color image by transferring a color image on a transfer member onto a recording material, a plurality of developing cartridges are installed in a developing rotary that rotates around a single axis by a driving source. Many electrophotographic image forming apparatuses employ a method in which the developing rotary is indexed and rotated so that the developing cartridge faces the electrophotographic photosensitive drum to form toner images of a plurality of colors on the electrophotographic photosensitive drum.
[0017]
In such an apparatus, it is necessary to stop the rotation operation of the developing rotary in order to replace the developing cartridge. For this reason, in general, there is a brake mechanism in which the rotation operation of the developing rotary is stopped or the stop is released in conjunction with the operation of the cover that is opened for replacing the developing cartridge.
[0018]
The brake is generally a method in which the rotation of the developing rotary is fixed by electrically exciting a drive source such as a stepping motor that rotates the developing rotary.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
[Description of Embodiments of the Invention]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0020]
In the following description, the short direction of the process cartridge C is the direction in which the process cartridge C is attached to and detached from the apparatus main body 14 and coincides with the conveyance direction of the recording medium. Further, the longitudinal direction of the process cartridge C is a direction intersecting (substantially orthogonal to) the direction in which the process cartridge C is attached to and detached from the apparatus main body 14, is parallel to the surface of the recording medium, and transports the recording medium. Is a direction intersecting (substantially orthogonal). The left and right with respect to the process cartridge is the right or left when the recording medium is viewed from above according to the conveyance direction of the recording medium.
[0021]
(Embodiment 1)
Embodiments of the present invention will be described below with reference to the drawings.
[0022]
{Overall configuration of image forming apparatus}
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an entire electrophotographic image forming apparatus (hereinafter referred to as an image forming apparatus) according to the present invention.
[0023]
First, an outline of the entire image forming apparatus A will be described with reference to FIG. The image forming apparatus A shown in the figure is a four-color full-color laser beam printer.
[0024]
The image forming apparatus A shown in FIG. 1 includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 3 as a first image carrier. The photosensitive drum 3 is rotationally driven counterclockwise in the drawing by a driving means (not shown). A charging device 32 that uniformly charges the surface of the photosensitive drum 3 in order according to the rotation direction around the photosensitive drum 3, and irradiates a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 3. As a second image carrier to which a toner image on the photosensitive drum 3 is primarily transferred, a scanner unit 107 which is an exposure unit to be formed, a developing device 34 which develops a toner image by attaching toner to an electrostatic latent image A cleaning device 36 for removing residual toner remaining on the surface of the intermediate transfer member 4 and the photosensitive drum 3 after the primary transfer is disposed.
[0025]
Here, the photosensitive drum 3, the charging device 32, and the cleaning device 36 for removing the toner are integrally formed into a cartridge to form a process cartridge C, which is detachable from the apparatus main body 14 of the image forming apparatus A.
[0026]
In addition, the recording material (third image carrier) 102 is fed toward the intermediate transfer member 4, and the feeding / conveying means 37 for conveying the recording material 102, and the toner image is applied to the recording material 102 after the secondary transfer. A fixing unit 104 for fixing is provided.
[0027]
Hereinafter, the photosensitive drum 3 will be described in detail.
[0028]
The photosensitive drum 3 is configured, for example, by applying an organic photoconductor layer (OPC photosensitive member) to the outer peripheral surface of an aluminum cylinder having a diameter of about 47 mm. Both ends of the photosensitive drum 3 are rotatably supported by a support member, and a driving force from a driving motor (not shown) is transmitted to one end, so that the photosensitive drum 3 is rotationally driven in the arrow direction. .
[0029]
As the charging device 32, for example, a so-called contact charging method as shown in Japanese Patent Laid-Open No. 63-149669 can be used. The charging member is a conductive roller formed in a roller shape. The roller is brought into contact with the surface of the photosensitive drum 3, and a charging bias voltage is applied to the roller by a power source (not shown), whereby the photosensitive member. The surface of the drum 3 is uniformly charged.
[0030]
The scanner unit 107 includes a polygon mirror 107a. The polygon mirror 107a is irradiated with image light corresponding to an image signal by a laser diode (not shown). The polygon mirror 107a is rotated at a high speed by a scanner motor (not shown), and the reflected image light is selectively exposed on the surface of the charged photosensitive drum 3 through an imaging lens (not shown), the reflection mirror 107b, and the like. Thus, an electrostatic latent image is formed.
[0031]
The developing device 34 includes a developing rotary 1 that can be indexed and rotated about the shaft core 2 and four developing devices mounted thereon, that is, a developer that stores toner of each color of yellow, magenta, cyan, and black. Cartridges Dy, Dc, Dm, Db are provided. When developing the electrostatic latent image on the photosensitive drum 3, any one of the predetermined developing cartridges Dy, Dc, Dm, and Db of the color to be attached to the electrostatic latent image is disposed at the developing position. That is, the gear 1a on the outer periphery of the developing rotary 1 and the motor gear 1b provided at the output shaft end of the stepping motor M0 are meshed with each other, and a predetermined developing cartridge due to the rotation of the stepping motor M0 is exposed by the indexing rotation of the developing rotary 1. The developing sleeve Ds of the developing cartridge is positioned so as to face the photosensitive drum 3 with a minute gap (about 300 μm), and then the static on the photosensitive drum 3 is stopped. Develop the electrostatic latent image. This development is performed as follows. The toner in the container of the developing cartridge corresponding to the color to be developed is sent to the application roller Dp by the feeding mechanism, and a thin layer of toner is applied to the outer periphery of the rotating development blade Ds by the rotating application roller Dp and the toner regulating blade Dt. In addition, the toner is charged (frictionally charged). By applying a developing bias between the developing sleeve Ds and the photosensitive drum 3 on which the electrostatic latent image is formed, the toner image is attached to the electrostatic latent image and developed as a toner image. Further, the developing sleeves Ds of the developing cartridges Dy, Dc, Dm, and Db are connected to high-voltage power supplies for developing the respective colors provided in the image forming apparatus main body 14 when the developing cartridges are arranged at the developing positions. A voltage is selectively applied for each color development. Each of the developing cartridges Dy, Dc, Dm, and Db is configured to be detachable from the developing rotary 1 and the developing rotary 1 can be attached to and detached from the apparatus main body 14.
[0032]
The intermediate transfer member 4 as a second image carrier is a member that secondary-transfers a plurality of toner images that are sequentially primary-transferred from the photosensitive drum 3 to the recording material 102 at once. The intermediate transfer member 4 includes an intermediate transfer belt 4a that travels in the direction of arrow R5. The intermediate transfer belt 4a of the present embodiment is a belt having a circumferential length of about 440 mm, and is stretched around three rollers: a drive roller 4b, a secondary transfer counter roller 4c, and a driven roller 4d. In the vicinity of the driven roller 4d, there is provided a pressing roller 4j that retreats so as to take a position where the intermediate transfer belt 4a is pressed against the photosensitive drum 3 and a position where the intermediate transfer belt 4a is separated from the photosensitive drum 3. The intermediate transfer belt 4a travels in the direction of the arrow R5 by the rotation of the driving roller 4b. Further, a cleaning unit 4e that can be brought into contact with and separated from the surface of the intermediate transfer belt 4a is provided at a predetermined position outside the intermediate transfer belt 4a. Remove toner. The toner to which the reverse charge is applied by the cleaning unit 4e is electrostatically attached to the photosensitive drum 3, and is then collected by the cleaning device 36 for the photosensitive drum 3. The cleaning method for the intermediate transfer belt 4a is not limited to the electrostatic cleaning described above, but may be a mechanical method such as a blade or a fur brush, or a combination thereof.
[0033]
The cleaning device 36 removes so-called transfer residual toner remaining on the surface of the photosensitive drum 3 without being primarily transferred after the toner developed on the photosensitive drum 3 by the developing device 34 is primarily transferred to the intermediate transfer belt 4a. To be removed. In the cleaning device 36 shown in the figure, the transfer residual toner is accumulated in the cleaning container 41a. In FIG. 1, the inside of the cleaning container 41a is not shown.
[0034]
The feeding / conveying unit 37 feeds the recording material 102 from the feeding unit 101 to the image forming unit, and stores a plurality of recording materials 102 and is loaded in the lower part of the image forming apparatus main body 14. A cassette 37a is provided. At the time of image formation, the pickup member 37e and the conveyance roller 37b are driven and rotated in accordance with the image forming operation to separate and feed the recording material 102 in the paper feed cassette 37a one by one, and are guided by the guide plate 37c, and the registration roller 37d. Is fed to the intermediate transfer belt 4a.
[0035]
The fixing unit 104 fixes a plurality of toner images secondarily transferred onto the recording material 102. As shown in FIG. 1, the fixing unit 104 is in contact with a driving roller 104a that rotates and heats the recording material 102 to heat. And a fixing roller 104b for applying pressure. That is, the recording material 102 that has passed through the secondary transfer roller 103 that collectively transfers the toner on the intermediate transfer belt 4a is conveyed by the driving roller 104a when passing through the fixing unit 104, and heat and pressure are applied by the fixing roller 104b. Applied. As a result, a plurality of color toner images are fixed on the surface of the recording material 102.
[0036]
An interlock power switch 109 is provided in the apparatus body 14 to be closed by being pushed by a dog 11b provided on the opening / closing cover 11 when the opening / closing cover 11 is closed. When the opening / closing cover 11 is opened, the interlock power switch 109 is opened, and power is supplied from the high-voltage power supply unit of the apparatus main body 14 to the high-voltage power supply metal part 108 for applying the developing bias to the developing cartridges Dy, Dc, Dm, Db. Is no longer done.
[0037]
Next, an image forming operation of the image forming apparatus configured as described above will be described.
[0038]
The photosensitive drum 3 is rotated in the direction of the arrow (counterclockwise) in FIG. 1 in synchronization with the rotation of the intermediate transfer belt 4 a, and the surface of the photosensitive drum 3 is uniformly charged by the charging device 32, and the scanner unit 107 The yellow image is irradiated with light to form a yellow electrostatic latent image on the photosensitive drum 3. Simultaneously with the formation of the electrostatic latent image, the developing device 34 is driven so that the yellow developing cartridge Dy is disposed at the developing position, and the yellow toner is attached to the electrostatic latent image on the photosensitive drum 3 so that the yellow toner adheres. A voltage having the same polarity as the charging polarity and substantially the same potential is applied to cause yellow toner to adhere to the electrostatic latent image for development. A yellow toner image on the photosensitive drum 3 is primarily transferred onto the intermediate transfer belt 4a by applying a voltage having a polarity opposite to that of the toner to the primary transfer roller (driven roller) 4d.
[0039]
When the primary transfer of the yellow toner image is completed as described above, the next developing cartridge Dc rotates and is positioned at the developing position facing the photosensitive drum 3, and in the same way as yellow, cyan, magenta, Then, for each color of black, electrostatic latent image formation, development, and primary transfer are sequentially performed, and four color toner images are superimposed on the intermediate transfer belt 4a. These toner images are secondarily transferred collectively to the recording material 102 supplied from the feeding / conveying means 37.
[0040]
Then, the recording material 102 after the secondary transfer is conveyed to the fixing unit 104, where the toner image is fixed, and then driven by the belt 106a wound around the discharge roller 105 and the belt 106a moving in the direction indicated by the arrow. The discharged rollers 106b are discharged onto a discharge tray 40 outside the image forming apparatus main body 14 to complete image formation.
[0041]
In the developing device 34 configured as described above, the developing cartridges Dy, Dc, Dm, and Db can be attached and detached from the radial direction of the developing rotary 1. When the opening / closing cover 11 constituting a part of the paper discharge tray 40 is rotated counterclockwise in FIG. 1 around the hinge 11a attached to the apparatus main body 14, an opening is generated and the Dy of the developing cartridge is generated. , Dc, Dm, Db appear. The developing cartridges Dy, Dc, Dm, and Db are detachably mounted in the same posture at four positions in the circumferential direction of the developing rotary 1 and equidistant from the shaft core 2. Therefore, when an operation button (not shown) for indexing the developing rotary 1 is pressed, the developing rotary 1 is indexed and a desired one of the developing cartridges Dy, Dc, Dm, Db is attached to the above-described opening / closing cover 11. Can rotate to position.
[0042]
Next, the main part of the present invention will be described. As shown in FIG. 3, the first gear 5 of the three gears configured in the mechanical brake mechanism M is always meshed with the gear 1 a formed on the outer periphery of the developing rotary 1. The first gear 5 is rotatably fitted to a shaft 13b fixed to a bracket 13 fixed to the side plate 14a of the apparatus main body 14 with a machine screw 13a. The second gear 6 and the third gear 7 are always meshed with the first gear 5. The second gear 6 is rotatably fitted to a fixed shaft 13 c fixed to the bracket 13. The third gear 7 is rotatably fitted to a fixed shaft 7 a fixed to a swinging member 8 that swings around the center of the first gear 5. Further, on the second gear 6 and the third gear 7 coaxially, elastic rollers 9 having a larger coefficient of friction and a diameter larger than the diameter of the tip of each gear are formed integrally with the gears 6 and 7, respectively. . The outer peripheral member of the roller 9 is rubber, for example.
[0043]
The rollers 9 formed integrally with the second gear 6 and the third gear 7 are biased by a biasing member such as a spring in a direction in which they contact each other. That is, the tension coil spring 10 is stretched between the bracket 13 and the swing member 8.
[0044]
As shown in FIG. 4, a protrusion 12 is provided on the opening / closing cover 11 that can be opened by the user in order to replace the developing cartridges Dy, Dc, Dm, and Db. The protrusion 12 is brought into contact with the cam portion 8a of the swing member 8 of the mechanical brake mechanism M by the closing operation of the opening / closing cover 11, so that the swing member 8 is centered on the fixed shaft 5a against the spring force of the tension coil spring 10. , The roller 9 formed integrally with the second gear 6 and the third gear 7 is separated from the contact, and the first gear 5, the second gear 6 and the third gear 7 are not The development rotary 1 becomes rotatable by being in a loaded state and being rotatable. On the contrary, when the opening / closing cover 11 is opened to replace the developing cartridges Dy, Dc, Dm, Db, the protrusion 12 of the opening / closing cover 11 is separated from the swing member 8 of the mechanical brake mechanism M, and the spring force of the tension coil spring 10 is changed. As a result, the rollers 9 formed integrally with the second gear 6 and the third gear 7 are urged in the direction of contact with each other, so that the first, second, third gears 5, 6 and 7 are all non-rotatable. . Therefore, since the gear 1a formed on the outer periphery of the developing rotary 1 is in a non-rotatable state, the rotational movement of the developing rotary 1 is stopped.
[0045]
Thereby, the rotation of the developing rotary 1 can be mechanically stopped in conjunction with the opening / closing operation of the opening / closing cover 11. Therefore, the interlock power switch 109 of the apparatus main body 14 can be turned off.
[0046]
For this reason, since the high-voltage current to the developing rotary 1 is cut off, it is not necessary to install a cover having a complicated shape around the high-voltage power supply metal part 108 to the developing cartridge, and the apparatus is not enlarged. Conventionally, the excitation force is remarkably weakened by the temperature rise of the motor when left unattended for a long time, which has been caused by the method of fixing the rotation of the developing rotary 1 by electrically exciting a drive source such as a stepping motor. However, when trying to insert the developing cartridge, the developing rotary is rotated, and the serious disadvantage that the developing cartridge cannot be inserted well can be avoided.
[0047]
[Embodiment 2]
Next, an image forming apparatus according to another embodiment of the present invention will be described with reference to FIG.
[0048]
The swing member 8 is configured such that a roller 9b formed integrally with the third gear 7 is pressed against a roller 9a formed integrally with the second gear 6 by a rotational moment generated by the rotation of the developing rotary 1. The position has its center of rotation. That is, the fixed shaft 5 a is fitted into the swing member 8.
[0049]
In this configuration, when the developing rotary 1 tries to rotate in the clockwise direction indicated by the arrow in FIG. 4, the tooth load between the gear 1 a and the first gear 5 is supported by the fixed shaft 5 a that supports the first gear 5. Is done. When the first gear 5 tries to rotate in the counterclockwise direction indicated by the arrow in the figure, the tooth load between the first gear 5 and the third gear 7 acts in the direction of the line of engagement of the two gears 5, 7. Force acting on the fixed shaft 7a that supports the third gear 7 as shown by the arrow a. . Since the fixed shaft 7a is fixed to the swing member 8, the roller 9b is pressed against the roller 9a by a moment for rotating the swing member 8 counterclockwise about the fixed shaft 5a. The rollers 9a and 9b, which are elastic members, are pressed against the rollers 9a and 9b by the force of the developing rotary 1 to rotate even if the peripheral surfaces of the rollers 9a and 9b move in opposite directions. It will be. Accordingly, a sufficient braking force applied to the developing rotary 1 can be secured. Since the spring force of the tension coil spring 10 can be reduced, the force with which the swing member 8 pushes the projection 12 of the opening / closing cover 11 can be reduced. Further, in the second embodiment, the fixed shaft 7a that supports the third gear 7 rotates around the fixed shaft 5a that supports the first gear 5, and therefore the first and third gears. 5 , 7 Are engaged with each other at a constant inter-axis distance.
[0050]
[Embodiment 3]
Next, an image forming apparatus according to Embodiment 3 of the present invention will be described with reference to FIG.
[0051]
A lever 21 is supported on the apparatus body 14 by a pin 14b so as to be swingable. One end of the lever 21 has a gear-shaped portion 21 a that can mesh with the gear 1 a of the developing rotary 1, and the other end that is pushed by the protrusion 12 of the opening / closing cover 11 when the opening / closing cover 11 is closed. The lever 21 is closed when the opening / closing cover 11 is closed and the other end is pushed by the projection 12 so that the gear-shaped portion 21a is disengaged from the gear 1a of the developing rotary 1, and when the opening / closing cover 11 is opened, the gear-shaped portion from the gear 1a is opened. 21a Mesh The position can be taken. Then, one end of the tension coil spring 22 is locked to the gear-shaped portion 21a side from the position supported by the pin 14b of the lever 21, the other end is locked to the apparatus main body 14, and the lever 21 rotates counterclockwise. Under the force, the gear-shaped portion 21 a is biased so as to be able to mesh with the gear 1 a of the developing rotary 1.
[0052]
The relationship of the interlock power switch is not shown, but is the same as in the first embodiment.
[0053]
When the opening / closing cover 11 is closed, the protrusion 12 rotates the other end of the lever 21 against the spring force of the tension coil spring 22, and the gear 1 a of the developing rotary 1 and the gear-shaped portion of the lever 21. Since 21a is disengaged, the developing rotary 1 can rotate, and image formation is performed in this state.
[0054]
When the developing cartridges Dy, Dc, Dm, and Db were replaced, the lever 21 that had been pressed by the protruding portion 12 when the opening / closing cover 11 was opened was pressed by the protruding portion 12 as the protruding portion 12 moved upward. The end portion is movable upward, the lever 21 swings counterclockwise around the pin 14b by the spring force of the tension coil spring 22, the gear-shaped portion 21a meshes with the gear 1a of the developing rotary 1, and the developing rotary 1 Is fixed. At the same time, the power of the developing rotary 1 is turned off by opening the power switch. Here, any one of the developing cartridges Dy, Dc, Dm, and Db is replaced.
[0055]
When the opening / closing cover 11 is closed after replacing the developing cartridge, the projection 12 pushes the other end of the lever 21 and the gear 1a and the gear-shaped portion 21a are disengaged.
[0056]
The bias of the lever 21 may be set such that the primary moment on the one end side of the gear 21 of the lever 21 with or without the tension coil spring 22 is greater than the primary moment on the other end side. It is valid.
[0057]
In this embodiment, since the gear-shaped portion 21a is engaged with the gear 1a of the developing rotary 1, the developing rotary 1 is fixed very strongly. Since the gear-shaped portion 21a may be a protrusion, the gear-shaped portion 21a does not have to be in the shape of a gear.
[0058]
According to the present embodiment, the developing rotary 1 rotates by four indexing rotations, that is, every 90 degrees. The developing rotary 1 is provided with indexing rotation position detecting means (not shown). Therefore, according to the present embodiment, the number of teeth of the gear 1a of the developing rotary 1 is, for example, 4n (n is a positive integer).
[0059]
With the configuration described above, the rotation of the developing rotary can be braked in conjunction with the movement of the opening / closing cover 11 opened by the user in order to replace the developing cartridges Dy, Dc, Dm, Db in a very inexpensive manner.
[0060]
As described above, according to this embodiment, the rotation of the developing rotary can be mechanically stopped in conjunction with the opening / closing operation of the opening / closing cover by installing a simple brake mechanism. Therefore, the interlock power switch of the main unit can be turned off in conjunction with the opening / closing operation of the opening / closing cover.
[0061]
Therefore, the high voltage current to the development rotary is interrupted. In addition, the excitation force is significantly weakened due to the temperature rise of the motor when left unattended for a long time, which was caused by the method of fixing the rotation of the developing rotary by electrically exciting a drive source such as a stepping motor. In this case, it was possible to avoid that the developing rotary was rotated and the developing cartridge could not be inserted well.
【The invention's effect】
As described above, according to the present invention, the rotation of the developing rotary can be mechanically stopped in a simple configuration in conjunction with the opening / closing operation of the opening / closing member. Therefore, it is not necessary to electrically excite the drive motor so that the development rotary does not rotate.
[Brief description of the drawings]
Each drawing shows an embodiment of the present invention,
FIG. 1 is a longitudinal sectional view showing a state where a brake of a developing rotary of an image forming apparatus of the present invention is released.
FIG. 2 is a longitudinal cross-sectional view showing the developing rotary of the image forming apparatus of the present invention when a brake is operated.
FIG. 3 is a perspective view of the brake mechanism of the present invention.
FIG. 4 is a front view of the brake mechanism of the present invention.
FIG. 5 is a front view of another embodiment 2 of the present invention.
[Explanation of symbols]
A: Image forming apparatus
C ... Process cartridge
Dy ... Yellow developer cartridge
Dc: Cyan developing cartridge
Dm ... Magenta developer cartridge
Db ... Black developing cartridge
Ds ... Development sleeve
Dp ... Application roller
Dt ... Toner regulating blade
M ... Mechanical brake mechanism
DESCRIPTION OF SYMBOLS 1 ... Development rotary 1a ... Gear formed in the outer periphery of rotary 1b ... Motor gear
2 ... Rotary shaft
3 ... Photosensitive drum
4 ... Intermediate transfer member 4a ... Intermediate transfer belt 4b ... Drive roller 4c ... Secondary transfer counter roller 4d ... Driven roller 4e ... Cleaning unit 4j ... Pressing roller
5 ... 1st gear comprised in the mechanical brake mechanism M 5a ... Fixed shaft
6 ... The second gear configured in the mechanical brake mechanism M
7 ... 1st gear comprised in the mechanical brake mechanism M 7a ... Fixed shaft
8: Swing member that rotates around the first gear 5
9, 9a, 9b... Elasticity with a large friction coefficient having a diameter larger than the diameter of the tip circle of each gear formed integrally with the gear on the same axis of the center axis of each of the second gear 6 and the third gear 7. Body roller
10 ... Tension coil spring
11: Open / close cover opened to replace developing cartridges Dy, Dc, Dm, Db 11a ... Hinge 11b ... Dog
12 ... Protrusions
13 ... Bracket 13a ... Machine screw 13b ... Shaft 13c ... Fixed shaft
14 ... device main body 14a ... side plate 14b ... pin
21 ... Lever 21a ... Gear-shaped part
22 ... Tension coil spring
32 ... Charging device
34. Developing device
36 ... Cleaning device
37... Feeding means 37 a.
40 ... Output tray
101 ... feeding section
102 ... Recording material
103 ... Secondary transfer roller
104 ... Fixing section 104a ... Drive roller 104b ... Fixing roller
105 ... discharge roller
106 ... discharge section 106a ... belt 106b ... discharge roller
107 ... Scanner 107a ... Polygon mirror 107b ... Reflection mirror
108 ... Metal parts for high-voltage power supply
109 ... Interlock power switch of the device body
MO ... Stepping motor

Claims (6)

In an electrophotographic image forming apparatus for forming an image on a recording medium,
A drive motor;
An electrophotographic photosensitive drum;
A rotatable developing rotary, a mounting portion for detachably mounting a developing cartridge for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, and an outer periphery of the developing rotary; A rotary gear that receives a driving force from the driving motor to move the developing cartridge;
An opening for mounting the developing cartridge to the mounting portion; an opening / closing member capable of taking an open position for opening the opening and a closed position for closing the opening;
A first gear meshing with the rotary gear, which is rotatably provided in the main body of the electrophotographic image forming apparatus;
A second gear that is rotatably provided in the apparatus main body and meshes with the first gear;
A third gear meshing with the first gear;
A first roller that rotates integrally with the second gear, the first roller having a diameter larger than the diameter of a tip circle of the second gear;
A second roller that rotates integrally with the third gear, the second roller having a diameter larger than the diameter of the tip circle of the third gear;
A swing member provided in the apparatus main body, rotatably supporting the third gear and the second roller, and moving in conjunction with the opening / closing member, wherein the opening / closing member is located at the open position. A contact position for contacting the second roller with the first roller, and a separation position for separating the second roller from the first roller when the opening / closing member is located at the closed position; A swinging member capable of taking
A biasing member that biases the swing member in a direction in which the second roller contacts the first roller;
An electrophotographic image forming apparatus comprising: Furthermore, the device body is
The electrophotographic image forming apparatus according to claim 1, further comprising a fixing member on which the first gear, the first roller, and the second gear are rotatably provided.   The fixing member, the swinging member supported by the fixing member so as to be swingable, and the biasing member are configured as an integral unit and fixed to the apparatus main body. Item 3. The electrophotographic image forming apparatus according to Item 2. In an electrophotographic image forming apparatus for forming an image on a recording medium,
A drive motor;
An electrophotographic photosensitive drum;
A rotatable developing rotary, a mounting portion for detachably mounting a developing cartridge for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, and an outer periphery of the developing rotary; A rotary gear that receives a driving force from the driving motor to move the developing cartridge;
An opening for mounting the developing cartridge to the mounting portion; an opening / closing member capable of taking an open position for opening the opening and a closed position for closing the opening;
A meshing member that moves in conjunction with the opening and closing member, and when the opening and closing member is in the open position, a meshing position that meshes with the rotary gear and prevents the developing rotary from rotating; When the opening / closing member is located at the closed position, a meshing member capable of taking a release position where the meshing with the rotary gear is released and the development rotary is allowed to rotate,
An electrophotographic image forming apparatus comprising:   The electrophotographic image forming apparatus according to claim 4, wherein the meshing member is a projection meshing with the rotary gear.   6. The electrophotographic image forming apparatus according to claim 4, further comprising a biasing member for biasing the meshing member to the meshing position when the opening / closing member is positioned at the open position. The electrophotographic image forming apparatus described in 1.

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