JP5315806B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  Conventionally, by applying toner to a photosensitive drum on which an electrostatic latent image has been formed, the toner image is developed on the surface of the drum, and the toner image is transferred to a substrate such as paper via a transfer belt, followed by a fixing process. An image forming apparatus that performs image formation such as printing and copying by performing the above is known.

A process cartridge in which a developing unit that applies toner contained in a toner container to a photosensitive drum by a developing roller and a photosensitive unit that forms a latent image of a desired image on the surface of the photosensitive drum is integrated. An image forming apparatus provided is known (for example, see Patent Document 1).
As described above, in the case of a process cartridge in which the developing unit and the photosensitive unit are integrated, when one unit has reached the end of its life, the other unit that can still be used has to be replaced.
JP 2003-162135 A

On the other hand, when the developing unit and the photosensitive unit are separated and each unit can be replaced individually, the surface of the developing roller of the developing unit and the photosensitive drum of the photosensitive unit are replaced when each unit is replaced. It is necessary to make it difficult for the developing roller and the photosensitive drum to come into contact with each other so that the surface of the photosensitive drum is not damaged.
However, since the space in the apparatus is limited due to the recent downsizing of the image forming apparatus, the retraction operation is performed to separate the developing unit and the photosensitive unit so that the developing roller and the photosensitive drum are difficult to contact. There were limitations.

  An object of the present invention is to provide an image forming apparatus capable of easily exchanging a developing unit and a photosensitive unit.

In order to solve the above problems, the invention described in claim 1
An image forming apparatus comprising: a photoreceptor unit having a photoreceptor on which a latent image is formed; and a developing unit that forms a developer image by attaching a developer to the photoreceptor.
The developing unit is provided movably by rotating around a predetermined support shaft to a retracted position separated from the photosensitive unit.
A replenishment path for replenishing the developer to the development unit is connected to the development unit from a developer accommodating portion in which the developer is accommodated.
The replenishment path is constituted by a bellows-shaped pipe, and the pipe has a pitch of the bellows on the outer surface of the replenishment path rather than the pitch of the inner surface of the replenishment path facing the photoconductor unit. by is formed longer than the inside surface in the supply path, characterized in that towards the outer surface of the supply passage is constituted by large extendible become structure.

According to a second aspect of the invention, in the image forming apparatus according to claim 1,
The replenishment path is connected to the developing unit so as to shrink in a direction in which the developing unit is brought closer to the photosensitive unit.

According to the present invention, in the image forming apparatus, the replenishment path connected between the developer accommodating portion and the developing unit is located on the outer surface of the replenishment path from the inner surface facing the photoreceptor unit. Since the developing unit is separated from the photosensitive unit and moved to the retracted position, the movement amount becomes longer based on the movement of the developing unit. This surface can be suitably extended.
The supply path can preferably follow the movement of the developing unit due to the deformation of the outer surface of the supply path, so that the supply path connected to the developing unit is disconnected from the developing unit. It is possible to avoid trouble that makes it difficult to replenish the developer.
Therefore, when the photosensitive unit or the developing unit in the image forming apparatus is replaced, the developing unit can be suitably moved to the retracted position, and the occurrence of problems related to the supply path connected to the developing unit can be prevented. Therefore, it is possible to easily replace the photoconductor unit and the developing unit.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus 10.
The image forming apparatus 10 is an apparatus that performs electrophotographic image formation based on input print data (image data), and is, for example, a tandem color page printer.

As shown in FIG. 1, the image forming apparatus 10 includes an image forming unit 20, a toner storage unit 30, a cleaning unit 40, a transfer belt 50, a paper feeding unit 60, a conveyance unit 70, a fixing unit 80, and the like. It is configured with.
Further, the image forming unit 20 has a photosensitive unit 1 having a photosensitive drum 21 on which an electrostatic latent image is formed, and a toner image (developer image) by attaching toner (developer) to the photosensitive drum 21. ) Is formed.

  The image forming unit 20 of the present embodiment can be charged with toners of different colors when forming images of up to four colors (yellow (Y), magenta (M), cyan (C), and black (K)). The image forming units 20Y, 20M, 20C, and 20K for each color are provided.

  The image forming unit 20Y includes, for example, a photosensitive unit 1Y including a photosensitive drum 21Y, a charging device 22Y, and a cleaning device 27Y, a developing unit 2Y including a toner conveying blade 24Y, and a developing roller 25Y, and an exposure device. 23Y and a transfer device 26Y, and a yellow (Y) image is formed.

  Specifically, a latent image is formed by irradiating light corresponding to yellow (Y) image data from the exposure device 23Y to the photosensitive drum 21Y as a photosensitive member charged by the charging device 22Y. The developing roller 25Y of the developing unit 2Y develops the toner image by attaching yellow (Y) toner to the surface of the photosensitive drum 21Y on which the latent image is formed. The photosensitive drum 21Y to which the toner is adhered by the developing roller 25Y transfers a yellow (Y) toner image onto the surface of the transfer belt 50 while rotating at a constant speed toward the transfer belt 50 portion where the transfer device 26Y is disposed. To do. After the toner image is transferred to the transfer belt 50, the cleaning device 27Y removes residual charges, residual toner, and the like on the surface of the photosensitive drum 21Y.

  The image forming units 20M, 20C, and 20K have the same configuration as the image forming unit 20Y, and include photoconductor units 1M, 1C, and 1K, development units 2M, 2C, and 2K, and the like, and photoconductor drums 21M, 21C. , 21K, charging devices 22M, 22C, and 22K, exposure devices 23M, 23C, and 23K, developing units 2M, 2C, and 2K, transfer devices 26M, 26C, and 26K, and cleaning devices 27M, 27C, and 27K, respectively. Magenta (M), cyan (C), and black (K) toner images are formed and transferred to the transfer belt 50.

  The toner storage unit 30 replenishes the developing units 2Y, 2M, 2C, and 2K to form images of up to four colors (yellow (Y), magenta (M), cyan (C), and black (K)), respectively. The toner storage units 30Y, 30M, 30C, and 30K are provided as developer storage units that store the toners of the respective colors.

As shown in FIGS. 2 and 3, the toner storage unit 30Y includes, for example, a toner cartridge 31Y that stores yellow (Y) toner and toner for transporting the toner in the toner cartridge 31Y toward the developing unit 2Y. A replenishing device 32Y and the like are provided.
2 and 3, the toner replenishing device 32Y is connected to one end of a bellows-like pipe 33Y, which is a replenishment path for replenishing yellow (Y) toner to the developing unit 2Y. The other end of the pipe is connected to the developing unit 2Y.
The toner replenishing device 32Y includes, for example, a rotatable screw roller 34Y. According to the rotation of the screw roller 34Y, the toner in the toner cartridge 31Y is supplied to the developing unit 2Y through the bellows-like pipe 33Y. It has become.

The developing unit 2Y temporarily stores yellow (Y) toner supplied from the toner storage unit 30Y.
As shown in FIGS. 2 and 3, for example, the developing unit 2Y feeds the toner contained therein to the developing roller 25Y by the rotation of the toner conveying blade 24Y, and the developing roller 25Y sends the toner to the photosensitive member. This is applied to the drum 21Y.
The developing unit 2Y is pivotally supported on the apparatus main body via a support shaft 28Y. The developing unit 2Y is rotatably provided with a support shaft 28Y as a fulcrum, a printing operation position where the developing roller 25Y of the developing unit 2Y is brought into contact with the photosensitive drum 21Y of the photosensitive unit 1Y, and the photosensitive drum. The arrangement can be switched to a retreat position for separating the developing roller 25Y from 21Y.
The support shaft 28Y is provided on the photosensitive unit 1Y side in the developing unit 2Y.

The toner storage units 30M, 30C, and 30K have the same configuration as the toner storage unit 30Y, and store toner of each color (magenta (M), cyan (C), and black (K)), and develop each toner. Replenish units 2M, 2C, 2K.
The developing units 2M, 2C, and 2K have the same configuration as the developing unit 2Y, and apply toners of respective colors (magenta (M), cyan (C), and black (K)) to the photosensitive drums 21M, 21C, and 21K, respectively. To do.

The transfer belt 50 is, for example, a semiconductive endless belt that is suspended and supported by a transfer driving roller 51, a tension roller 52, and a driven roller 53, and is driven to rotate as the roller rotates.
The transfer belt 50 is pressure-bonded to the photosensitive drums 21Y, 21M, 21C, and 21K by transfer devices 26Y, 26M, 26C, and 26K. As a result, the toner images of the respective colors (yellow, magenta, cyan, and black) developed on the surfaces of the photoconductive drums 21Y, 21M, 21C, and 21K are sequentially superimposed and transferred onto the transfer belt 50.

The paper feed unit 60 includes a paper feed tray 61 that can be attached to and detached from the image forming apparatus 10. The paper feed tray 61 stores paper of a predetermined size.
Further, a paper feed roller 62 is provided above the paper feed tray 61, and the paper stored in the paper feed tray 61 is transported one by one from the top toward the transport unit 70 by the paper feed roller 62. To do.

The transport unit 70 transports the paper transported from the paper feed tray 61 to a transfer position corresponding to the transfer drive roller 51 portion of the transfer belt 50 by driving a plurality of transport rollers 71.
A transfer roller 72 is provided at the transfer position to bring the conveyed paper into close contact with the surface of the transfer belt 50, and the toner image on the transfer belt 50 is transferred to the paper passing through the transfer position.
After each toner image is transferred to the paper at the transfer position, residual toner and the like are removed from the transfer belt 50 by the cleaning unit 40.

The fixing unit 80 includes, for example, a fixing roller 81 with a built-in heater, a pressure roller 82 that is pressed against the fixing roller 81, and the like. An elastic body layer is provided on the surfaces of the fixing roller 81 and the pressure roller 82, and can be brought into close contact with each other while being elastically deformed.
The fixing unit 80 heats and presses the sheet conveyed by the conveying unit 70 between the fixing roller 81 and the pressure roller 82, thereby thermally fixing the toner image transferred to the sheet.
The paper that has been subjected to the fixing process in the fixing unit 80 is discharged onto a paper discharge tray 90 by a paper discharge roller 91.

  Next, the contact / separation movement of the developing unit 2 with respect to the photosensitive unit 1 and the bellows-like pipe 33 in the image forming apparatus 10 according to the present invention will be described.

Since the photoconductor unit 1 and the developing unit 2 in the image forming apparatus 10 are so-called consumables, each unit is replaced with a new unit when it reaches the end of its service life.
When the unit is replaced, if the photosensitive drum 21 of the photosensitive unit 1 and the developing roller 25 of the developing unit 2 remain in contact with each other, the surface of the usable drum or roller may be damaged. Therefore, the developing unit 2 is separated from the photosensitive unit 1 and the developing unit 2 is moved to the retracted position.
The photosensitive drum 21 of the photosensitive unit 1 is a unit that should maintain a predetermined arrangement with respect to the transfer belt 50 in order to transfer the toner image formed on the surface thereof to the transfer belt 50. The arrangement of the developing unit 2 instead of the body unit 1 is preferably switchable, and the developing unit 2 is configured to be movable.

However, since the space in the apparatus is limited due to the recent downsizing of the image forming apparatus, the toner container 30 is disposed at a position away from the developing unit 2 as in the image forming apparatus 10 shown in FIG. There are things you have to do. When there is such a restriction, a toner supply is performed by connecting a tubular supply path such as a tube or a pipe between the toner container 30 and the developing unit 2.
When the replenishment path is attached to the developing unit 2, the replenishment path should preferably follow the movement associated with the switching of the arrangement of the development unit 2. It was necessary to avoid a situation where the toner was removed, torn, or crushed and it became difficult to replenish toner thereafter.
Therefore, in the image forming apparatus 10 of the present invention, the expandable bellows-like pipe 33 is used as the supply path, and the toner containing unit 30 and the developing unit 2 are connected.

The bellows-shaped pipe 33 is a bellows-like pipe configured such that the outer surface of the bellows-shaped pipe 33 can extend from the inner surface of the bellows-shaped pipe 33 facing the photoreceptor unit 1.
Specifically, as shown in FIGS. 4 and 5, the bellows in the bellows-shaped pipe 33 has a longer bellows pitch on the outer surface than the bellows pitch on the inner surface in the bellows-shaped pipe 33. The outer surface having a longer bellows pitch is more extensible than the inner surface.

The inner surface of the bellows-shaped pipe 33 is a surface on the photosensitive unit 1 side in a state where the bellows-shaped pipe 33 is attached to the developing unit 2, and the outer surface of the bellows-shaped pipe 33 is This is the surface on the opposite side of the photoreceptor unit 1 when the bellows-like pipe 33 is attached to the developing unit 2.
Further, the inner surface of the bellows-shaped pipe 33 is a surface on the support shaft 28 side of the developing unit 2 in a state where the bellows-shaped pipe 33 is attached to the developing unit 2, and is outside the bellows-shaped pipe 33. It is also a surface that is closer to the support shaft 28 than the surface. That is, the outer surface of the bellows-shaped pipe 33 is outside the rotation centering on the support shaft 28 than the inner surface of the bellows-shaped pipe 33. With the rotation of the developing unit 2 having the support shaft 28 as an axis, the outer surface of the bellows-like pipe 33 rotates with a longer turning radius than the inner surface.

FIG. 4 shows a printing operation state of the image forming unit 20 in the image forming apparatus 10.
As shown in FIG. 4, in the printing operation state, the developing unit 2 is rotated clockwise in the drawing around the support shaft 28, and the developing roller of the developing unit 2 is moved to the photosensitive drum 21 of the photosensitive unit 1. It is switched to the arrangement in which 25 is brought into contact.
In the arrangement of the printing operation state, the developing unit 2 can apply toner to the photosensitive drum 21 of the photosensitive unit 1.

In particular, in the arrangement in the printing operation state, the bellows-like pipe 33 is connected and attached between the toner storage unit 30 and the developing unit 2 in a state where the bellows-like pipe 33 is slightly stretched from the most contracted state. Reference numeral 33 is connected to the developing unit 2 so as to contract in the direction in which the developing unit 2 is brought closer to the photosensitive unit 1.
That is, when the bellows-like pipe 33 attached between the toner containing portion 30 and the developing unit 2 contracts, the developing unit 2 is attracted to the toner containing portion 30 side, and the developing unit 2 is attached to the photoreceptor unit 1. It is energized to come close.
As the bellows-like pipe 33 contracts in this way, the developing unit 2 is brought close to the photosensitive unit 1 so that the developing roller 25 of the developing unit 2 is moved to the photosensitive drum of the photosensitive unit 1. 21 can be suitably brought into contact with each other, and the arrangement of the developing units 2 in the printing operation state can be favorably maintained.

On the other hand, FIG. 5 shows a standby state of the image forming unit 20 in the image forming apparatus 10.
As shown in FIG. 5, when each unit is replaced, the developing unit 2 is rotated counterclockwise in the drawing around the support shaft 28, and the developing unit 2 is retracted away from the photosensitive unit 1. It is switched to the state arrangement (retreat position).

In a state where the developing unit 2 is disposed at the retracted position, the bellows-like pipe 33 is connected between the toner containing portion 30 and the developing unit 2 in a state where the bellows-like pipe 33 is further extended than in the printing operation state.
In particular, since the developing unit 2 rotates around the support shaft 28 and moves away from the photosensitive unit 1, the developing unit 2 is located away from the photosensitive unit 1 in the developing unit 2. The amount of movement of the unit 2 away from the support shaft 28 is longer.
In other words, the outer surface of the bellows-like pipe 33 connected to the developing unit 2 has a relatively longer turning radius with the support shaft 28 as the axis than the inner surface on the photoconductor unit 1 side. For this reason, since the arc-shaped movement amount becomes longer, the bellows-like pipe 33 preferably follows the movement accompanying the switching of the arrangement of the developing unit 2 by extending the outer surface from the inner surface. become.

In this way, by making the bellows pitch of the outer surface of the bellows-like pipe 33 longer and making it extendable than the inner surface, the support shaft 28 is centered when the developing unit 2 is moved to the retracted position. Due to the rotation of the developing unit 2, the outer surface of the bellows-like pipe 33 whose movement amount is long is preferably extended.
The bellows-like pipe 33 is suitable for the rotation of the developing unit 2 due to the deformation in which the outer surface of the bellows-like pipe 33 extends more than the inner surface in accordance with the movement of the developing unit 2 to the retracted position. Therefore, there is no problem in connection and connection of the bellows-like pipe 33.

As described above, in the image forming apparatus 10, the bellows-like pipe 33 attached between the toner storage unit 30 and the developing unit 2 has a bellows so that the outer surface extends more than the inner surface. Therefore, when the developing unit 2 is moved away from the photosensitive unit 1 and the developing unit 2 is moved to the retracted position, the outside of the bellows-like pipe 33 whose moving amount becomes longer based on the rotation of the developing unit 2. This surface can be suitably extended.
The bellows-like pipe 33 can suitably follow the rotation of the developing unit 2 due to the deformation of the outer surface of the bellows-like pipe 33, so that the bellows-like pipe connected to the developing unit 2 can be obtained. 33 does not come off from the developing unit 2, and the bellows-like pipe 33 is not torn or crushed, so that it is possible to avoid trouble that makes it difficult to supply toner thereafter.

Therefore, when replacing the photosensitive unit 1 or the developing unit 2, the developing unit 2 can be suitably moved to the retracted position, and problems associated with the bellows-like pipe 33 connected to the developing unit 2 can be generated. Can be prevented.
Therefore, the image forming apparatus 10 can easily replace the photoreceptor unit 1 and the developing unit 2.

  In the above embodiment, the tubular supply path is the bellows-like pipe 33. However, the present invention is not limited to this. For example, the outer surface of the pipe is made of the material of the inner surface of the pipe. This material may be formed of a highly elongated resin or the like to form a tubular supply path.

Further, in the image forming apparatus 10, since the replacement frequency of the photosensitive unit 1K of the image forming unit 20K for black (K) is high, the bellows-like pipe 33K for supplying toner to the developing unit 2K of the image forming unit 20K is used. It is particularly preferable to apply the technique of the present invention.
The image forming apparatus is not limited to a color printer, and may be a monocolor printer.

  The image forming apparatus is not limited to a tandem type color page printer, but may be a multifunction machine having a copy function.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

1 is a schematic configuration diagram illustrating an image forming apparatus. FIG. 4 is a front view showing a toner storage unit, a bellows pipe, and a developing unit. FIG. 3 is a side view of the toner storage unit, the bellows pipe, and the development unit from the direction of arrow III in FIG. FIG. 7 is an explanatory diagram illustrating a printing operation state in which a developing unit is brought into contact with a photosensitive unit. FIG. 6 is an explanatory diagram illustrating a retracted state in which the developing unit is separated from the photosensitive unit.

Explanation of symbols

10 Image forming apparatus 1 (1Y, 1M, 1C, 1K) Photosensitive unit 2 (2Y, 2M, 2C, 2K) Developing unit 20 (20Y, 20M, 20C, 20K) Image forming unit 21 (21Y, 21M, 21C, 21K) Photosensitive drum (photosensitive member)
25 (25Y, 25M, 25C, 25K) Developing roller 28 (28Y, 28M, 28C, 28K) Support shaft 30 (30Y, 30M, 30C, 30K) Toner container (developer container)
33 (33Y, 33M, 33C, 33K) Bellows-shaped pipe (supply path)

Claims (2)

An image forming apparatus comprising: a photoreceptor unit having a photoreceptor on which a latent image is formed; and a developing unit that forms a developer image by attaching a developer to the photoreceptor.
The developing unit is provided movably by rotating around a predetermined support shaft to a retracted position separated from the photosensitive unit.
A replenishment path for replenishing the developer to the development unit is connected to the development unit from a developer accommodating portion in which the developer is accommodated.
The replenishment path is constituted by a bellows-shaped pipe, and the pipe has a pitch of the bellows on the outer surface of the replenishment path rather than the pitch of the inner surface of the replenishment path facing the photoconductor unit. by is formed longer than the inside surface in the supply path, the image forming apparatus characterized by towards the outer surface of the supply passage is constituted by large extendible become structure . The image forming apparatus according to claim 1 , wherein the replenishment path is connected to the developing unit so as to contract in a direction in which the developing unit is brought closer to the photosensitive unit.

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