JP3074088B2 - Developing cartridge and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming a multi-color image such as a full-color image by utilizing an electrophotographic system or the like, and a developing cartridge used for the same.

[0002]

2. Description of the Related Art FIG. 12 shows an example of a conventional image forming apparatus for obtaining a multicolor image using an electrophotographic system. The image forming apparatus has a photosensitive drum 200 at a substantially central portion, and image exposure is performed on the photosensitive drum 200 by the optical unit 207 to sequentially form latent images of respective colors. Each time a latent image of each color is formed, a developing device d of each color disposed around the photosensitive drum 200, that is, a yellow developing device dy and a magenta developing device d
m, the toner images are sequentially developed by the cyan developing device dc and the black developing device db, and toner images of respective colors are sequentially formed on the photosensitive drum 200.

A transfer drum 203 is provided on the opposite side of the photosensitive drum 1 from the developing device.
03 is supplied with the recording material 202. The leading end of the recording material 202 is gripped by a gripper 203f on the outer periphery of the transfer drum 203, and is conveyed while being held on the outer periphery by rotation of the transfer drum 203. The toner images of each color formed on the photosensitive drum 200 are sequentially superimposed and transferred onto a recording material 202 held on the outer periphery of the transfer drum 203 in an image transfer unit facing the transfer drum 203, and are transferred. A multicolor image consisting of four toner images is obtained on the top.

[0004] Recording material 202 onto which four color toner images have been transferred
After that, the toner image is separated from the transfer drum 203 and transported to the fixing unit 204, where the toner image is fixed to mix the toner of each color and fix the toner image to the recording material 202 to form a full-color permanent image. After, discharge roller pair 2
At 05, the sheet is discharged onto the sheet discharge tray 206.

Each of the developing devices dy to db is held by a developing device switching mechanism 208, and a predetermined developing device d is moved to a developing position facing the photosensitive drum 1 by rotation of the switching mechanism 208, and The developing device for developing the electrostatic latent image is switched. Further, toner replenishing mechanisms 209y, 209c, 209m, and 209b are connected to the respective developing devices dy, dc, dm, and db to replenish the respective toners.

[0006]

By the way, in order to simplify the maintenance of the developing device and the toner replenishment so that the user can handle the developing device, it has been attempted to make each developing device into a cartridge.

In this case, it is necessary to prevent the worker from soiling his / her hand or clothes when mounting or replacing the developing cartridge, and to prevent the developer carrying member of the developing cartridge from being damaged. This problem has been dealt with by covering the developer carrier of the developing cartridge with a cover. Therefore, when the developing cartridge is newly mounted on the switching mechanism and used, the cover must be removed.

It is an object of the present invention to provide a developing cartridge having improved operability at the time of replacement.

Another object of the present invention is to provide an image forming apparatus capable of exchanging developing cartridges of respective colors with good operability.

[0010]

The above object is achieved by a developing cartridge and an image forming apparatus according to the present invention. In summary, the present invention has at least a developing unit having a developer carrier and a developer accommodating unit for accommodating the developer, and is removably mounted on a moving mechanism and moved to a developing position facing the image carrier. In the developing cartridge, the developing cartridge is a developing device having the developing unit and the developer accommodating unit, and a supporting container having an opening that accommodates the developing device and supports the developing device so as to be relatively rotatable; A lock member that holds the support container and the developing device in such a manner that the opening and the developer carrier do not face each other in a non-rotatable relationship with each other; A first engagement member for holding the posture of the container in a predetermined posture, and a second engagement member for engaging with a release member provided on the moving mechanism to release the lock member, the first engagement member being attached to the moving mechanism. When
And a second engaging member that engages with the release member after the first engaging member engages with the attitude holding member.

The present invention is also directed to a developing cartridge of each color having at least a developing section having a developer carrying member and a developer accommodating section accommodating the developer, and an image carrier having the developing cartridge of each color detachably mounted. By rotating the developing cartridge around the axis parallel to the body axis, the developing cartridge of each color is moved to a developing position facing the image carrier, and a developing cartridge for developing a latent image on the image carrier is selected. And a developing cartridge switching mechanism for switching between the developing units, wherein the developing cartridges of the respective colors are relatively rotatable by accommodating the developing units having the developing unit and the developer accommodating unit and the developing units. And a lock that holds the support container and the developing unit so that they cannot rotate with each other in a positional relationship where the opening and the developer carrier do not face each other. The switching mechanism comprises: a position holding member for holding the developing cartridge in a predetermined position; and a lock member after the developing cartridge mounted on the switching mechanism is engaged with the position holding member. And a releasing member for releasing the image.

[0012]

【Example】

Embodiment 1 A developing cartridge according to an embodiment of the present invention and an image forming apparatus having the same will be described with reference to FIGS. 1 to 7 and FIG. First, the overall configuration of the image forming apparatus will be schematically described with reference to FIG.

As shown in FIG. 11, the present image forming apparatus
A process cartridge C having an electrophotographic photosensitive drum 1, a primary charging unit 2 and a cleaner 3 is provided at a substantially central portion.
A waste toner container 4 is mounted outside the cleaner 3.

The image forming apparatus rotates the photosensitive drum 1 in the direction of the arrow in synchronism with the rotation of the transfer drum 103 placed adjacent thereto, and uniformly charges the surface of the photosensitive drum 1 with the charging means 2. Charges. At the same time, light corresponding to the yellow image is irradiated on the primary charged photosensitive drum 1 by the optical scanner 107 to form a latent image of the yellow image on the photosensitive drum 1.

The optical scanner 107 has a laser diode (not shown). When the laser diode receives an image signal, it generates image light corresponding to the image signal and irradiates the polygon mirror 107a with the image light. This polygon mirror 1
The image light reflected at 07a is irradiated onto the photosensitive drum 1 from an exposure unit of the process cartridge C via a coupling lens and a reflecting mirror 107b (not shown), and latent images of each color are selectively formed on the photosensitive drum 1 sequentially. You.

Prior to the formation of the latent image, the developing cartridge switching mechanism S provided adjacent to the process cartridge C is rotated so that the yellow developing cartridge Dy mounted on the switching mechanism S faces the photosensitive drum 1. Move to the development position. The switching mechanism S includes a rotating body 15 that is a developing cartridge holding member. The rotating body 15 has a rotating shaft 15 a parallel to the rotating shaft of the photosensitive drum 1 at the center.
Developing cartridges D containing toner of each color, that is, a yellow developing cartridge Dy, a magenta developing cartridge Dm, a cyan developing cartridge Dc, and a black developing cartridge Db are detachably mounted on the rotating body 15, whereby the developing cartridges Dy to Db is detachable from the image forming apparatus main body. The developing cartridge and its switching mechanism S will be further described later.

When the yellow developing cartridge Dy is moved to the developing position, the developing sleeve 1 serving as the developer carrying member is moved.
0b (see FIG. 1) to carry and transport the toner, and apply a developing bias voltage having the same polarity and substantially the same potential as the charging polarity for forming the latent image on the photosensitive drum 1 to the developing sleeve 10b. Photosensitive drum 1 facing 10b
The upper latent image is developed by attaching yellow toner to it, and is visualized as a yellow toner image.

In synchronization with the formation of the yellow toner image on the photosensitive drum 1, the transfer drum 103 provided on the side of the process cartridge C opposite to the developing cartridge switching mechanism S
Then, the transfer material 102 is fed from the paper feeding unit 101. A transfer material 102 is stacked and stored in a paper feed cassette 101a, and one sheet of the transfer material 102 is separated and fed to a transfer drum 103 by rotating a feed roller 101b.

Transfer material 10 fed to transfer drum 103
2 is a gripper 10 on the outer periphery of the transfer drum 103
3f, and is held on the outer peripheral surface of the transfer drum 103 by electrostatic attraction by the attraction roller 103g.
The transfer material 102 held on the transfer drum 103 is conveyed toward the image transfer unit facing the photosensitive drum 1 by rotation of the transfer drum 103, and the yellow image on the photosensitive drum 1 is transferred by a transfer charging unit (not shown). You.

When the transfer of the yellow toner image is completed as described above, the same applies to cyan, magenta, and black. The primary charging of the photosensitive drum 1, the formation of each latent image, the cyan developing cartridge Dc, and the magenta developing cartridge Dm and the black developing cartridge Db, and the resulting cyan toner image, magenta toner image and black toner image are transferred onto the transfer material 102 on which the yellow image has been transferred.
A color image in which color toner images are superimposed is obtained.

Transfer material 102 onto which four color toner images have been transferred
Is then separated from the transfer drum 103 and the fixing unit 10
The toner image is fixed to the transfer material 102 to fix the toner image of each color, and the toner image is fixed to the transfer material 102 to form a full-color permanent image.
Is discharged onto the paper discharge tray 106, and the image formation is completed.

According to the present invention, each of the developing cartridges D includes, as shown in FIG.
Developing unit 10 at least integrating a developing unit 10c having a toner storage unit 10a storing the toner and a developing sleeve 10b to which toner is supplied from the toner storage unit 10a.
And accommodated the developing device 10 and supported so as to be relatively rotatable about a rotation axis parallel to the rotation axis of the developing sleeve 10b.
A substantially cylindrical support container 1 having an opening 11a on its periphery
1 and a lock member 12 movably supported near the center of the end face of the developing device 10 and constantly urged radially outward of the developing device 10 by a spring member 13.

As shown in FIG. 3, a circular notch is provided at the end surface of the support container 11, and as shown in FIG. 1, the claw 12b of the lock member 12 is provided at the notch end (see FIG. 6). )
There is provided a groove 11b into which the groove 11b fits. When the developing cartridge D is not attached to the image forming apparatus, the lock member 12 is fitted into the groove 11b by the elastic biasing force of the spring member 13, so that the support container 11 and the developing device 10 are engaged with each other and The developing sleeve 10b is locked in a non-rotational state, and is held at a position where the developing sleeve 10b is separated from the opening 11a of the support container 11, as shown in FIG. That is, at this time, the developing sleeve 10b
Is covered by the peripheral wall of the support container 11, and the scattering of the developer and the damage of the developing sleeve 10b can be prevented.

As shown in FIGS. 4 and 5, the developing cartridge switching mechanism S includes a developing cartridge rotating support 15 having four semi-cylindrical chambers each having a four-leaf clover-shaped cross section. Developing unit attitude control member 14 disposed at one end (the end in the developing cartridge insertion direction) of each of the two hollow cylinders, and a developing cartridge comprising a projection with a hole inside the attitude control member 14. A support 16 is formed. The developing cartridge D is held on the support 15 in a predetermined posture (orientation) by fitting the boss 10 d provided on the developing device 10 of the developing cartridge D into the hole of the support portion 16.

At the developing position facing the photosensitive drum 1, the attitude control member 14 is attached to the end face of the rotary support 15 in the same direction as described above in order to move and position the developing cartridge D in the direction of the photosensitive drum 1 to enable development. It is installed so that it can be moved. In order to return the developing cartridge D to the original position in the direction opposite to the photosensitive drum 1 at the developing position after the development, a spring 17 for urging the member 14 in the same direction is applied to the attitude control member 14.

On the other hand, a rotating member 15 for pressing the developing cartridge D in the direction of the photosensitive drum 1 at the developing position is non-rotatably carried on the rotating shaft 15a of the developing cartridge support 15.

As shown in FIGS. 4 and 6, when the developing cartridge D is moved in the axial direction of the developing sleeve 10b at the mounting / removing position of the apparatus main body different from the developing position and inserted into the rotary support 15 along the axis. As shown in FIG. 7, a fitting boss 10d formed on the distal end face of the developing device 10 in the insertion direction is provided.
Are fitted in the developing cartridge support portion 16, and then the unlocking protrusions 14 formed on the attitude control member 14.
a pushes the arm portion 12a formed on the lock member 12 against the elastic force of the spring 13, displaces the lock member 12 inward in the radial direction and removes the lock member 12 from the groove 11b.
The lock between the developing device 10 and the support container 11 by the second claw 12b is released. Therefore, after that, the operator holds the knob 11e (FIG. 4) of the support container 11 and rotates the support container 11 in the X direction of FIG.
The opening 1 of the support container 11 is provided at the position of the developing sleeve 10b.
1a, the developing sleeve 10b is exposed to the outside.
0b can be brought to a position facing the photosensitive drum 1. In the illustrated example, the developing sleeve 10b of each developing cartridge always faces outward in the radial direction of the support 15.

According to the present embodiment, as shown in FIG. 4, the support container 11 of the developing cartridge D and the main assembly of the apparatus are used to adjust the insertion angle (position in the circumferential direction) of the developing cartridge D to be inserted into the support 15. A corresponding convex portion 11c for guiding, a fitting hole 100b, and a fitting groove 15a can be provided at about two places in the circumferential direction in the insertion opening 100a and the developing cartridge support body 15 provided in the side plate 100, respectively. This can prevent the developer cartridge D from being inserted at an incorrect angle when it is mounted.

When the developing cartridge D is mounted on the apparatus main body, and the developing sleeve 10b is exposed by rotating the supporting container 11 as described above, the supporting container 11 is
Of the projection 11c is displaced from the position corresponding to the fitting hole 100b.
c mechanically interferes with the inner surface of the side plate 100 and cannot be taken out. That is, unless the support container 11 is rotated in the direction opposite to the X direction to shield the developing sleeve 10 b with the peripheral wall of the container 11, the developing cartridge D cannot be removed from the support 15.

When the toner in the toner container 10a of the developing device 10 is exhausted and the developing cartridge D is replaced, the operation reverse to the above is performed.

That is, at the developing cartridge attaching / detaching position, the supporting container 11 is turned in the opposite direction to the above, and the developing sleeve 10b is shielded by the peripheral wall surface of the container 11. Next, the developing cartridge D is pulled out in the direction opposite to the direction when the developing cartridge D is mounted. On this occasion,
Before the boss 10d comes out of the developing cartridge support portion (fitting hole) 16 of the attitude control member 14, the locking member 1
The second arm portion 12a comes off the unlocking projection 14a. As a result, when the attitude of the developing cartridge D is still held at the predetermined attitude, the lock member 12
The developing device 10 and the support container 11 are locked so that they cannot rotate with each other, by being fitted into the groove 11b of the support container 11 by the urging force of 3. Thereafter, the boss 10d is inserted into the fitting hole 1 of the posture control member 14.
6 and then the developing cartridge D is pulled out of the main body.

Here, the height relationship between the fitting boss 10d of the developing device 10 and the arm portion 12a of the lock member 12 is such that the fitting boss 10d is high in the present embodiment, but the positioning of the developing device 10 is performed. Is performed prior to unlocking, the arm portion 12a may be higher as shown in FIG.

In the present invention, since the developing cartridge D and its switching mechanism S are configured as described above, when the user takes out the developing cartridge D from the apparatus main body and mounts a new developing cartridge D, it is always required. Since the developing sleeve 10b of the developing device 10 is covered by the support container 11 and the developing sleeve 10b is opened and closed only in a state where the developing cartridge D is held in the predetermined position on the rotary support 15, the toner Contamination and damage to the developing sleeve 10b can be easily prevented. Further, since the lock of the developing device 10 with respect to the support container 11 can be released only by inserting the developing cartridge D into the apparatus main body, workability at the time of mounting the developing cartridge D is improved.

Embodiment 2 FIG. 9 is a front view showing a developing cartridge switching mechanism according to another embodiment of the present invention. A major feature of this embodiment is that a planetary gear mechanism is used for the developing cartridge switching mechanism. Other configurations of the present embodiment are shown in FIGS.
11 is basically the same as the first embodiment described with reference to FIG. 11, and the members having the same configuration as the first embodiment are denoted by the same reference numerals in FIG. 9 and the description thereof is omitted.

The developing cartridge switching mechanism S 'in this embodiment comprises an attitude control section 20 and a rotating support 21. The attitude control unit 20 includes a center sun gear 22 fixed to a rotation shaft 21 a of a rotation support 21, and an attitude control gear 24 provided at a mounting position of each developing cartridge.
And an idle gear 23 provided between the sun gear 22 and each attitude control gear 24 and meshing with them. Further, in order to move the developing cartridge D in the direction of the photosensitive drum 1 at the developing position facing the photosensitive drum 1 to enable development, the developing cartridge D movably supported on each attitude control gear 24 in the same direction as described above. A cartridge support member 25 (similar to the attitude control member 14 shown in FIGS. 4 and 5) is provided. In order to return the developing cartridge to the original position in the opposite direction to the photosensitive drum 1 after development, the support member 25 Is provided with a return spring 26 which urges in the same direction as above.

On the other hand, a pressing member 27 for pressing the developing cartridge D against the photosensitive drum 1 is fixed to the rotating shaft 21a of the rotating support 21 so as not to rotate. The sun gear 22 and the attitude control gear 24 are formed to have the same number of teeth, and since the sun gear 22 is fixed to the rotating shaft 21a, when the attitude control unit 20 and the rotary support 21 rotate integrally, The attitude control gear 24 rotates around the rotation shaft 21a without changing its attitude. Therefore, the support members 25 provided on the gear 24 always face the same direction.

Therefore, when the developing cartridge D is inserted and mounted on the rotary support 21 at the mounting / detaching position, the developing unit 10 and the supporting container 11 of FIG.
The lock with is released. Further, in this mounting state, the developing cartridge D is in a posture when the developing device 10 faces the photosensitive drum 1 and the opening 11a of the supporting container 11
Is already held in the same posture (orientation) as the posture located at the location of the developing unit 10c, and this posture is changed to the switching mechanism S '.
Is maintained unchanged during the conveyance by the rotation of the toner cartridge, so that the inserting operation of the developing cartridge D is simplified, and the toner aggregates in the vicinity of the developing sleeve which is the developer carrying member and the developing blade which is the developer layer thickness regulating member. Such adverse effects can be eliminated. In addition, the opening 1 of the support container 11 except for the developing position.
Since 1a is not located outside the rotating body 25, the toner can be prevented from spilling.

Embodiment 3 In this embodiment, as shown in FIG. 10, instead of the attitude control gear 24 of the attitude control section 20 in Embodiment 2 described with reference to FIG. Embodiment 2 is that an attitude control gear 24 'in which a developing roller D is directly formed is used, and a long hole 25a having the same length as the moving amount of the developing cartridge D at the developing position is formed in a supporting member 25'.
And different.

The elongated hole 25a is provided in the developing cartridge D
Is formed obliquely upward with respect to the pressing direction, the developing cartridge D after the development at the developing position returns to the original position by its own weight. Therefore, according to this embodiment, there is an advantage that the return spring can be omitted.

[0040]

As described above, according to the present invention, the developing cartridge of each color is provided with a developing unit having a developing unit having a developer carrier and a developer accommodating unit accommodating a one-component developer. A supporting container that accommodates the container and is rotatably supported,
A holding member for holding the developing device in a non-rotatable manner with respect to the support container, and a switching mechanism for detachably mounting the developing cartridge of each color, moving to a developing position facing the image carrier, selecting and switching, A release member is provided to release the holding member when the developing cartridge is mounted, so that the developing unit is located at a position other than the opening of the support container, and the developer cartridge of each color can be easily operated in a posture in which the developer is unlikely to leak or scatter. Can be exchanged well.

Further, by providing a planetary gear mechanism in the switching mechanism, the operability of exchanging the developing cartridge of each color is further improved, and the developing cartridge of each color can always be maintained at a constant posture, and adverse effects such as toner spilling and agglomeration. Can also be prevented.

[Brief description of the drawings]

FIG. 1 is a front view showing a developing cartridge according to an embodiment of the present invention.

FIG. 2 is a front view illustrating a state where the developing cartridge of FIG. 1 is in a developing posture after being mounted on a switching mechanism provided in the image forming apparatus.

FIG. 3 is a perspective view of the developing cartridge of FIG. 1;

FIG. 4 is a perspective view showing a state where the developing cartridge of FIG. 1 is mounted on a rotating body of a switching mechanism.

FIG. 5 is a front view showing a switching mechanism to which the developing cartridge of FIG. 1 is mounted.

FIG. 6 is a side view showing a state where the developing cartridge of FIG. 1 is mounted on a rotating body of a switching mechanism.

FIG. 7 is a side view showing a state where the lock of the lock member provided on the developing cartridge is released by the mounting of FIG. 6;

FIG. 8 is an explanatory diagram showing another example of the attitude control mechanism.

FIG. 9 is a front view showing a developing cartridge switching mechanism according to another embodiment of the present invention.

FIG. 10 is a front view showing a developing cartridge switching mechanism according to still another embodiment of the present invention.

FIG. 11 is an overall configuration diagram showing an image forming apparatus of the present invention.

FIG. 12 is an overall configuration diagram showing a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 10 Developing device 11 Support container 11a Opening 12 Lock member 14 Attitude control member 15 Developing cartridge rotating body D Developing cartridge S Developing cartridge switching mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/08-15/095

Claims (3)

(57) [Claims] An image forming apparatus includes: a developing unit having a developer carrier; and a developer accommodating unit accommodating the developer. The developer accommodating unit is detachably mounted on a moving mechanism and is moved to a developing position facing the image carrier. In the developing cartridge, the developing cartridge includes a developing device having the developing unit and the developer accommodating unit, a supporting container having an opening that accommodates the developing device and rotatably supports the developing device, and A lock member that holds the container and the developing device so that they cannot rotate relative to each other in a positional relationship in which the opening and the developer carrier do not face each other; and a locking member that engages with a posture holding member provided in the moving mechanism to move the developing device. A first engaging member for holding the posture in a predetermined posture, and a second engaging member for releasing the lock member by engaging with a releasing member provided on the moving mechanism, the first engaging member being mounted on the moving mechanism. ,
And a second engagement member that engages with the release member after the first engagement member engages with the attitude holding member. 2. A developing cartridge of each color having at least a developing section provided with a developer carrier and a developer accommodating section accommodating the developer, and a shaft of the image carrier having the developing cartridge of each color detachably mounted. The developing cartridge for each color is moved to a developing position facing the image carrier by rotating about an axis parallel to the image carrier, and a developing cartridge for developing a latent image on the image carrier is selected and switched. In the image forming apparatus provided with a developing cartridge switching mechanism, the developing cartridges of the respective colors are supported by the developing unit having the developing unit and the developer accommodating unit, and the developing unit are relatively rotatably accommodated. A support container having an opening, and a lock member that holds the support container and the developing unit so that they cannot rotate with each other in a positional relationship where the opening and the developer carrier do not face each other. Wherein the switching mechanism includes a posture holding member that holds the developing cartridge in a predetermined posture,
An image forming apparatus comprising: a release member that releases the lock member after the developing cartridge mounted on the switching mechanism engages with the attitude holding member. 3. The image forming apparatus according to claim 2, wherein the developing cartridge switching mechanism includes an attitude control mechanism for maintaining the developing unit in a predetermined constant attitude in response to rotation of the developing cartridge of each color by the switching mechanism. apparatus.