JP7317287B2 - developer container, image forming apparatus - Google Patents

Description

The present invention relates to a developer container and an image forming apparatus provided with the developer container.

In an electrophotographic image forming apparatus, the surface of an image carrier such as a photosensitive drum that moves on the surface is charged by a charging member such as a charging roller to form an electrostatic latent image. is adhered to form a developer image, and the developer image is transferred onto a transfer material such as a recording medium or an intermediate transfer member.

A charging member that charges the surface of a photosensitive drum by contact with the photosensitive drum is repeatedly used, and foreign matter such as an external additive adheres and accumulates on the surface of the charging member. As a result, foreign matter accumulates on the charging member, causing an abnormal image such as a streak image. Conventionally, it is known to provide a cleaning member for cleaning the charging member against adhesion of foreign matter to the charging member.

For example, in the image forming apparatus disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-53370), a photosensitive member, a charging roller, a charging roller cleaning member, a cleaning blade, etc. form an integrated photoconductor unit. removes foreign matter from the surface of the charging roller.

In addition to the provision of the cleaning member as described above, there has been a demand for measures to prevent foreign matter from accumulating on the surface of the charging member and causing abnormal images.

In order to solve the above problems, the present invention includes a container body, a charging member for contacting an image carrier and charging the image carrier, a holding member for holding the charging member, and the holding member. a pressing member for pressing the charging member against the image bearing member, wherein the holding member is a longitudinal member, one side of which is attached to the container main body, and the other side of which is attached to the charging member. or indirectly holding the charging member via another member .

According to the present invention, deposition of foreign matter on the surface of the charging member can be suppressed.

1 is a schematic configuration diagram of an image forming apparatus; FIG. 4 is a diagram showing a state in which an upper cover of the image forming apparatus is opened; FIG. 3 is a cross-sectional view showing a process cartridge and a toner cartridge; FIG. 3 is a perspective view of a holding frame and its peripheral members; FIG. FIG. 2 is a cross-sectional view showing a process cartridge and a toner cartridge in which a guide portion is provided in the image forming apparatus; FIG. 3 is a cross-sectional view showing a process cartridge and a toner cartridge having cleaning rollers; FIG. 7 is a perspective view of a holding frame and its peripheral members in FIG. 6; FIG. 11 is a perspective view showing a modified example of a toner cartridge including a holding frame; FIG. 10 is a perspective view showing a modified example of a toner cartridge including a holding frame; FIG. 10 is a perspective view showing a modified example of a toner cartridge including a holding frame; FIG. 10 is a perspective view showing a modified example of a toner cartridge including a holding frame;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant description thereof will be appropriately simplified or omitted.

First, referring to FIG. 1, the overall configuration and operation of a color laser printer according to one embodiment of the present invention will be described. However, the present invention is not limited to this. The configuration of the present invention can also be applied to image forming apparatuses such as monochrome printers, other printers, copiers, facsimiles, and multifunction machines of these.

As shown in FIG. 1, four process cartridges 1Y, 1M, 1C, and 1Bk as image forming units are detachably attached to an apparatus main body (image forming apparatus main body) 100 of a color laser printer. Each of the process cartridges 1Y, 1M, 1C, and 1Bk contains different color toners (developers) of yellow (Y), magenta (M), cyan (C), and black (Bk) corresponding to color separation components of a color image. It has the same configuration except that it is accommodated.

Specifically, each of the process cartridges 1Y, 1M, 1C, and 1Bk includes a drum-shaped photosensitive drum 2 as an image carrier, and a charging roller 3 as a charging member for charging the surface of the photosensitive drum 2. a developing device 4 for supplying toner to the latent image on the photoreceptor drum 2; and a cleaning device including a cleaning blade 5 for cleaning the surface of the photoreceptor drum 2. . In FIG. 1, only the photosensitive drum 2, the charging roller 3, the developing device 4, and the cleaning blade 5 of the yellow process cartridge 1Y are denoted by reference numerals. are omitted. Further, in this embodiment, a one-component developer made of toner is used as the developer. However, the developer is not limited to this, and may be a two-component developer consisting of toner and carrier.

Above the four developing devices 4 of each of the process cartridges 1Y, 1M, 1C, and 1Bk, there is provided a toner cartridge 50 as a developer container containing toner to be supplied to each developing device 4. It is

An exposure device 6 for exposing the surface of the photosensitive drum 2 of each of the process cartridges 1Y, 1M, 1C, and 1Bk is arranged near the bottom of each toner cartridge 50. As shown in FIG. The exposure device 6 has a light source, a polygon mirror, an f-.theta.

At the top of the apparatus main body 100, an upper cover 109 that can be opened and closed vertically by rotating about a fulcrum 110 and an inner cover that can be opened and closed vertically by rotating about a fulcrum 117 are provided. 116 is provided.

A transfer device 7 is arranged below each of the process cartridges 1Y, 1M, 1C, and 1Bk. The transfer device 7 has an intermediate transfer belt 8 made up of an endless belt as a transfer body. The intermediate transfer belt 8 is stretched between a drive roller 9 and a driven roller 10. As the drive roller 9 rotates counterclockwise in the drawing, the intermediate transfer belt 8 circulates in the direction indicated by the arrow in the drawing ( rotating).

Four primary transfer rollers 11 as primary transfer means are arranged at positions facing the four photosensitive drums 2 . Each primary transfer roller 11 presses the inner circumferential surface of the intermediate transfer belt 8 at its respective position, and a primary transfer nip is formed at a location where the pressed portion of the intermediate transfer belt 8 and each photosensitive drum 2 contact each other. It is Each primary transfer roller 11 is connected to a power supply, and a predetermined direct current (DC) and/or alternating voltage (AC) is applied to the primary transfer roller 11 .

A secondary transfer roller 12 as a secondary transfer means is provided at a position facing the driving roller 9 . The secondary transfer roller 12 presses the outer peripheral surface of the intermediate transfer belt 8 , and a secondary transfer nip is formed where the secondary transfer roller 12 and the intermediate transfer belt 8 contact each other. Like the primary transfer roller 11 , the secondary transfer roller 12 is connected to a power supply, and a predetermined direct current (DC) and/or alternating voltage (AC) is applied to the secondary transfer roller 12 . ing.

A belt cleaning device 13 for cleaning the surface of the intermediate transfer belt 8 is arranged on the outer peripheral surface of the intermediate transfer belt 8 on the right end side of the drawing. A waste toner transfer hose extending from the belt cleaning device 13 is connected to an entrance portion of a waste toner container 14 arranged below the transfer device 7 .

A paper feed cassette 15 for storing paper P as a recording medium is arranged in the lower part of the apparatus main body 100 . The paper feed cassette 15 is provided with a paper feed roller 16 for sending out the paper P contained therein. On the other hand, a pair of paper ejection rollers 17 for ejecting the paper P to the outside is arranged on the upper part of the apparatus main body 100 . A paper discharge tray 18 for stocking the paper P discharged by the paper discharge rollers 17 is provided on the upper cover 109 .

A transport path R for transporting the paper P from the paper feed cassette 15 to the paper discharge tray 18 through the secondary transfer nip is arranged in the apparatus main body 100 . On the transport path R, a pair of registration rollers 19 as transport means for transporting the paper P to the secondary transfer nip at the timing of transport are arranged upstream of the position of the secondary transfer roller 12 in the paper transport direction. ing. A fixing device 20 is arranged downstream of the position of the secondary transfer roller 12 in the sheet conveying direction.

The image forming apparatus operates as follows.
When the image forming operation is started, the photosensitive drums 2 of the process cartridges 1Y, 1M, 1C, and 1Bk are driven to rotate clockwise in FIG. is uniformly charged. An exposure device 6 irradiates the charged surface of each photoreceptor drum 2 with laser light based on the image information of the document read by the image reading device, forming an electrostatic latent image on the surface of each photoreceptor drum 2 . be. At this time, the image information to be exposed on each photosensitive drum 2 is monochromatic image information obtained by decomposing a desired full-color image into yellow, magenta, cyan and black color information. As toner is supplied from each developing device 4 to the electrostatic latent image formed on the photosensitive drum 2 in this way, the electrostatic latent image is developed (visualized) as a toner image. .

Subsequently, the driving roller 9 around which the intermediate transfer belt 8 is stretched is driven to rotate, and the intermediate transfer belt 8 is caused to circulate in the direction of the arrow in the figure. Further, by applying a constant voltage having a polarity opposite to the charging polarity of the toner or a voltage controlled by a constant current to each primary transfer roller 11, primary transfer between each primary transfer roller 11 and each photosensitive drum 2 is performed. A transfer field is formed at the nip. Then, the toner images of the respective colors on the respective photosensitive drums 2 are sequentially superimposed and transferred onto the intermediate transfer belt 8 by the transfer electric field formed in the primary transfer nip. The intermediate transfer belt 8 thus carries a full-color toner image on its surface. Further, the toner on each photosensitive drum 2 that has not been completely transferred to the intermediate transfer belt 8 is removed by the cleaning blade 5 .

On the other hand, in the paper feed cassette 15 , the paper P contained therein is sent out to the transport path R by rotating the paper feed roller 16 . The paper P sent out to the conveying path R is sent to the secondary transfer nip between the secondary transfer roller 12 and the intermediate transfer belt 8 with timing by the registration rollers 19 . At this time, a transfer voltage having a polarity opposite to that of the toner image on the intermediate transfer belt 8 is applied to the secondary transfer roller 12, thereby forming a transfer electric field in the secondary transfer nip. Then, the toner image on the intermediate transfer belt 8 is collectively transferred onto the paper P by the transfer electric field formed in the secondary transfer nip. Toner remaining on the intermediate transfer belt 8 after transfer is removed by a belt cleaning device 13, and the removed toner is conveyed to a waste toner container 14 and collected.

After that, the paper P to which the toner image has been transferred is conveyed to the fixing device 20 , and the toner image on the paper P is fixed to the paper P in the fixing device 20 . Then, the paper P is discharged outside the apparatus by a pair of paper discharge rollers 17 and is stocked on a paper discharge tray 18 .

Next, a structure for attaching and detaching the toner cartridge 50 to and from the apparatus main body 100 will be described with reference to FIGS. 1 and 2. FIG.

As shown in FIG. 1, the inner cover 116 is attached to the apparatus main body 100 so as to be vertically openable and closable by rotating about a fulcrum 117 . Toner cartridges 50 containing toner of each color can be mounted on the inner cover 116 . As shown in FIG. 2, the toner cartridge 50 can be attached and detached with the upper cover 109 opened. Further, by further opening the inner cover 116 from the state of FIG. 2, the process cartridge 1 and the photosensitive drum 2 can be replaced while the toner cartridge 50 is attached.

The above description is for the image forming operation when forming a full-color image on the paper P, but any one of the four process cartridges 1Y, 1M, 1C, and 1Bk can be used to form a single-color image, or two process cartridges can be used. It is also possible to form two-color or three-color images using one or three process cartridges.

Next, more detailed configurations of the process cartridge 1 (for example, the process cartridge 1Y) and the toner cartridge 50 will be described.

As shown in FIG. 3, the process cartridge 1 has a developing device 4, a photosensitive drum 2, a cleaning blade 5, and the like. A toner cartridge 50 is provided above the developing device 4 .

Photoreceptor drum 2 and cleaning blade 5 are held by common frame 21 .

The developing device 4 includes a developing housing 40 containing toner, a developing roller 41 as a developer carrying member for carrying the toner, a supply roller 42 as a developer supplying member for supplying toner to the developing roller 41, and a developing roller. It has a developing blade 43 as a regulating member for regulating the amount of toner carried on the surface 41, two conveying screws 44 and 45 for conveying toner, and the like.

The developing operation of the developing device 4 will be described with reference to FIG.
When there is an instruction to start the image forming operation and the developing roller 41 and the supply roller 42 start rotating, the toner is supplied to the surface of the developing roller 41 by the supply roller 42 and carried thereon. As the toner carried on the developing roller 41 passes through the nip portion between the developing roller 41 and the developing blade 43, the thickness of the toner layer is regulated and is triboelectrically charged. Then, when the toner on the developing roller 41 is conveyed to a position (developing area) facing the photosensitive drum 2, the toner is electrostatically transferred to the electrostatic latent image on the photosensitive drum 2 to form a toner image. It is formed.

The toner cartridge 50 includes a container body 51 having a space for containing toner therein, an agitator 52 as an agitating member for agitating the toner in the container body 51, and extending in a direction perpendicular to the plane of FIG. It has a conveying screw 53 as a conveying member, a holding frame 54 as a holding member, and the like. The agitator 52 and the conveying screw 53 are provided inside the container body 51 . A discharge port 51a for discharging the toner in the container body 51 to the outside is provided at a position facing the developing device 4 of the container body 51 .

When the toner amount detection mechanism detects that the toner amount in the developing housing 40 has become equal to or less than the reference amount, the conveying screw 53 and the agitator 52 in the toner cartridge 50 start rotating. As the conveying screw 53 rotates, the toner is conveyed toward the discharge port 51a, and the toner is replenished into the developing housing 40 from the discharge port 51a. The rotation of the agitator 52 agitates the toner in the toner cartridge 50 and transports the toner to the rotation area of the conveying screw 53 . When the amount of toner in the developing housing 40 exceeds a predetermined reference value, the conveying screw 53 and the agitator 52 stop rotating, and toner replenishment ends.

Further, as shown in FIG. 4, the holding frame 54 is a pair of elongated members, and the shaft portions of the charging roller 3 are inserted into one ends 54a thereof. In other words, the holding frame 54 is a pair of arm-shaped members that hold the charging roller 3 from both sides in the axial direction.

As shown in FIG. 3, the other end 54b of the holding frame 54 is attached to the container body 51. As shown in FIG. The other end 54b of the holding frame 54 is provided with a spring 55 as a pressing member. In this embodiment, the spring 55 is a torsion spring. One end 55 a of the spring 55 is fixed to the container body 51 , and the other end 55 b is in contact with the contact portion 54 c provided on the holding frame 54 . Due to the elastic restoring force of the spring 55, the holding frame 54 receives force in the counterclockwise rotating direction in FIG. Thereby, the charging roller 3 is pressed against the photosensitive drum 2, and a good contact state can be formed.

A rotation stopping member 56 is attached to the container body 51 . The rotation stopping member 56 is provided downstream of the holding frame 54 in the direction in which the spring 55 presses the holding frame 54 .

The rotation stop member 56 is a member that abuts on the holding frame 54 to regulate the rotation range of the holding frame 54 . For example, when the toner cartridge 50 is assembled to the process cartridge 1, before the charging roller 3 contacts the photosensitive drum 2, the rotational force of the holding frame 54 rotated by the elastic restoring force of the spring 55 is applied to the photosensitive drum. 2 cannot be received. Therefore, by providing the rotation stop member 56 at the position described above, it is possible to prevent the holding frame 54 from rotating more than necessary.

In the present embodiment, by providing the charging roller 3 on the holding frame 54 provided in the toner cartridge 50, the charging roller 3 can be replaced with a new one at the same time as the toner cartridge 50 is replaced. For example, unlike the present embodiment, when compared to the configuration in which the charging roller 3 is held by the frame 21 that holds the photosensitive drum 2, the timing of replacing the toner cartridge 50 is earlier than the timing of replacing the photosensitive drum 2. Therefore, the charging roller 3 can be replaced earlier. Therefore, in the configuration of the present embodiment, it is possible to prevent the occurrence of an abnormal image due to adhesion of foreign matter such as an external additive to the toner that occurs over time to the charging roller 3 .

A frame 21 that holds the photosensitive drum 2 and the cleaning blade 5 is provided with a guide portion 22 for guiding the holding frame 54 in its insertion direction and arranging the charging roller 3 at an appropriate position. By providing the guide portion 22 , the positional deviation of the holding frame 54 to the left in the drawing is regulated, and contact between the charging roller 3 and the cleaning blade 5 is prevented. This can prevent the charging roller 3 from being damaged.

Instead of the guide portion 22 described above, a guide portion may be provided on the body side housing of the image forming apparatus. Further, the target to be guided is not limited to the holding frame 54, and may be a shaft portion (see FIG. 4) of the charging roller 3 passing through the holding frame 54. FIG. For example, in the image forming apparatus shown in FIG. 5, an apparatus body 100 is provided with a guide shape 101 (guide portion 101) for guiding the shaft portion of the charging roller 3. As shown in FIG. The guide shape 101 has a shape in which the path narrows toward the mounting position of the charging roller 3 (the position where it slides on the photosensitive drum 2). By providing the guide shape 101, the shaft portion of the charging roller 3 is guided by the guide portion 101 when the toner cartridge 50 is assembled to the process cartridge 1, such as when the toner cartridge 50 is replaced. can be smoothly arranged at an appropriate position. Therefore, the ease of assembly of the toner cartridge 50 is improved, and the charging roller 3 can be properly brought into contact with the photosensitive drum 2 .

Further, a configuration in which a cleaning roller for cleaning the surface of the charging roller 3 may be provided. For example, the image forming apparatus shown in FIGS. 6 and 7 is provided with a cleaning roller 23 as a cleaning member that contacts the charging roller 3 .

As with the charging roller 3, the cleaning roller 23 has its shaft held by the holding frame 54 and is rotatable around the shaft. The cleaning roller 23 slides on the rotating charging roller 3 and can remove foreign matter adhering to the surface of the charging roller 3 .

Further, in the present embodiment, as described above, by providing the holding frame 54 for holding the charging roller 3 in the toner cartridge 50, the replacement frequency of the charging roller 3 is increased. In addition to this, by providing the cleaning roller 23 for cleaning the charging roller 3 , it is possible to more reliably prevent the formation of abnormal images due to adhesion of foreign matter to the surface of the charging roller 3 .

Further, a pressing member for pressing the charging roller 3 against the photosensitive drum 2 may be provided inside the holding frame 51 .

For example, as shown in FIG. 8, in this embodiment, the holding frame 54 has a slide hole 54d on one end side 54a. A spring 57 as a pressing member is provided in the slide hole 54d. Both ends of the shaft portion of the charging roller 3 are supported by bearings 58, and the bearings 58 are held by the holding frame 54 so as to be slidable in the slide holes 54d.

The end of the spring 57 opposite to the side fixed to the holding frame 54 is fixed to a bearing 58, and biases the bearing 58 toward one end of the holding frame 54 (see FIG. 1). (see arrow direction). The urging force of the spring 57 presses the charging roller 3 toward the photosensitive drum 2 (see FIG. 5), stabilizing the contact state between the charging roller 3 and the photosensitive drum 2, so that the two rotate together more stably. state can be formed.

Further, as shown in FIG. 9, a cleaning roller 23 may be further provided in the above configuration. In this case, the bearing 58 supports the shaft portions of the charging roller 3 and the cleaning roller 23, as shown in FIG. Both the charging roller 3 and the cleaning roller 23 are pressed toward the photosensitive drum 2 by the spring 57 . Thereby, a good contact state between the charging roller 3 and the photosensitive drum 2 and between the charging roller 3 and the cleaning roller 23 can be formed.

Further, the configuration of the holding frame 54 having a different configuration and its surroundings will be described with reference to FIG. 10 .
As shown in FIG. 10 , in this embodiment, a bearing 59 that supports the shaft of the charging roller 3 is held by the holding frame 54 . More specifically, one end of the bearing 59 holds the shaft of the charging roller 3 . A shaft provided on one end 54 a of the holding frame 54 is inserted into the hole on the other end side of the bearing 59 , so that it is attached (held) to the holding frame 54 . The bearing 59 is provided rotatably with respect to the holding frame 54 around the other end side held by the holding frame 54 .

A spring 60 as a pressing member is provided between the bearing 59 and the holding frame 54 . The spring 60 is a torsion spring, one end 60a of which is inserted into the hole of the holding frame 54 and abuts against the inner wall surface of the holding frame 54, and the other end 60b of which is inserted into the hole of the bearing 59 to engage the bearing. It abuts on the inner wall surface of 59 . With such a configuration, the elastic restoring force of the spring 60 urges the bearing 59 and the charging roller 3 clockwise (see the arrow direction in the drawing). The urging force of the spring 60 presses the charging roller 3 toward the photosensitive drum 2 (see FIG. 5), stabilizing the contact state between the charging roller 3 and the photosensitive drum 2, so that the two rotate together more stably. state can be formed.

Further, as shown in FIG. 11, a cleaning roller 23 may be further provided in the above configuration. In this case, as shown in FIG. 11, bearings 59 support the shafts of charging roller 3 and cleaning roller 23 . Even with such a configuration, the biasing force of the spring 60 can press the charging roller 3 toward the photosensitive drum 2 (see FIG. 5).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

Recording media include paper P (plain paper), thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet, plastic film, prepreg, copper foil, and the like. included.

1 process cartridge 2 photoreceptor drum (image carrier)
3 charging roller (charging member)
4 developing device 22 guide section 23 cleaning roller (cleaning member)
50 toner cartridge (developer container)
51 container body 54 holding frame (holding member)
55 spring (pressing member)
56 rotation stop member 57 spring (pressing member)
58 bearing 59 bearing 60 spring (pressing member)
100 image forming apparatus main body 101 guide shape (guide portion)
P paper (recording medium)

Japanese Patent Application Laid-Open No. 2012-53370

Claims (7)

a container body;
a charging member for contacting the image carrier and charging the image carrier;
a holding member that holds the charging member;
a pressing member for pressing the holding member and pressing the charging member against the image carrier ;
The holding member is an elongated member, one side of which is attached to the container body, and the other side of which directly holds the charging member or indirectly holds the charging member via another member. A developer container characterized by: a container body;
a charging member having a shaft portion and contacting the image carrier to charge the image carrier;
a bearing that holds an axial end of the shaft;
a holding member that holds the bearing;
a pressing member for pressing the bearing to press the charging member against the image carrier ;
A developer container according to claim 1, wherein said holding member is a longitudinal member, one side of which is attached to said container body, and the other side of which holds said charging member indirectly via said bearing. the bearing holds the shaft portion of the charging member on one side, is held by the holding member on the other side, and is rotatable with respect to the holding member about the other side;
3. A developer container according to claim 2, wherein said pressing member presses said bearing so that said bearing rotates about the other side and presses said charging member against said image carrier. 4. The developer container according to any one of claims 1 to 3 , further comprising a cleaning member that contacts the charging member and cleans the charging member. 5. An image forming apparatus, wherein the developer container according to any one of claims 1 to 4 is detachably provided. 6. The image forming apparatus according to claim 5 , further comprising a guide portion for guiding said holding member toward a predetermined mounting position. The charging member has a shaft,
6. The image forming apparatus according to claim 5 , further comprising a guide portion for guiding said shaft portion and for guiding said charging member to a predetermined mounting position.

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