JP6684469B2 - Powder conveying device and image forming device - Google Patents

Description

  The present invention relates to a powder carrying device and an image forming apparatus.

  2. Description of the Related Art Conventionally, in image forming apparatuses such as copiers, facsimiles, printers, etc., a toner conveying pipe that guides toner that is powder to a conveying destination and the inner wall of the toner conveying pipe are in contact with each other to crosslink the toner by adhesion of the toner to the inner wall. There is known one using a toner conveying device provided with a cross-linking prevention member for preventing the above.

  For example, Patent Document 1 describes a toner transport device that uses a spring coil as a cross-linking prevention member. This toner carrying device includes a first toner carrying pipe that houses a toner carrying coil and a second toner carrying pipe that is connected to the first toner carrying pipe and carries the toner in the gravity direction by the weight of the toner. I have it. A spring coil that moves up and down by the rotation of the toner carrying coil is provided in the second toner carrying pipe. The spring coil scrapes off the toner adhering to the inner wall of the second conveying pipe, so that the viscosity of the toner becomes high at a high temperature and the like, and the toner adheres to the inner wall of the pipe to cause toner cross-linking, which causes clogging. It is said that this can be prevented.

  However, in the toner conveying device of Patent Document 1, since the spring coil is used as the cross-linking preventing member, the toner rides on the entire linear region of the spring coil, and the toner carried on the spring coil is deposited on the inner wall of the toner carrying pipe. There is a risk of adhesion.

In order to solve the above-mentioned problems, the present invention provides a powder carrying device including a powder carrying pipe for guiding powder to a carrying destination by its own weight, and a bridge preventing member provided in the powder carrying pipe, The cross-linking prevention member is a plate member that is movable in the powder transfer pipe by contacting the inner wall of the powder transfer pipe, and the side surface of the plate member is parallel to the powder transfer direction in the powder transfer pipe. And in the end surface of the plate member on the upstream side in the powder conveying direction in the powder conveying pipe, the width direction length of the powder conveying pipe on the side surface of the plate member is from the conveying direction upstream to the downstream. It is characterized in that it has an inclined portion that becomes longer toward the end .

  According to the present invention, it is possible to prevent the powder from adhering to the inner wall of the powder transfer tube in the powder transfer tube that transfers the powder by its own weight.

1 is a schematic configuration diagram of a copying machine according to an embodiment. FIG. 3 is a perspective view of a toner supply unit included in the printer. FIG. 3 is a perspective view showing an overall configuration of the toner supply unit and the developing device. Sectional drawing of the principal part of the toner supply unit. FIG. 6 is an explanatory diagram of a connecting portion between the link portion and the oscillating plate member of the toner replenishing unit. The perspective view which shows the attachment state of the same link part and a rocking | fluctuation board member. The figure explaining the structure of the same oscillating plate member. Explanatory drawing which looked at the operating state of the same link part from the axial direction of the screw. FIG. 7 is a cross-sectional view of the main part of a conventional toner supply unit.

Hereinafter, an embodiment of a color laser printer (hereinafter referred to as "printer 1") as an image forming apparatus to which the present invention can be applied will be described.
FIG. 1 is a schematic configuration diagram of a printer 1 according to the embodiment.
The printer 1 is provided with four image forming units 4 (Y, M, C, K) at the center of its main body. The image forming units 4 (Y, M, C, K) develop different colors of yellow (Y), magenta (M), cyan (C), and black (K) corresponding to the color separation components of the color image. It has the same configuration except that it contains the agent.
Specifically, each image forming unit 4 (Y, M, C, K) includes a drum-shaped photoconductor 5 as a latent image carrier, a charging device 6 that charges the surface of the photoconductor 5, and a photoconductor. A developing device 7 that supplies toner to the surface of the photoconductor 5, a cleaning device 8 that cleans the surface of the photoconductor 5, and the like are provided.

In FIG. 1, reference numerals are given only to the photoconductor 5, the charging device 6, the developing device 7, and the cleaning device 8 included in the black image forming unit 4K, but the other three image forming units 4 (Y, M, C). ) Also has a similar configuration.
An exposure device 9 that exposes the surface of the photoconductor 5 is disposed below the four image forming units 4 (Y, M, C, K). The exposure device 9 has a light source, a polygon mirror, an f-θ lens, a reflection mirror, etc., and irradiates the surface of each photoconductor 5 with laser light based on image data.
The transfer device 3 is disposed above the four image forming units 4 (Y, M, C, K). The transfer device 3 includes an intermediate transfer belt 30, four primary transfer rollers 31, a secondary transfer roller 36, a secondary transfer backup roller 32, a cleaning backup roller 33, a tension roller 34, and a belt cleaning device 35. Equipped with.

The intermediate transfer belt 30 is an endless belt and is stretched around a secondary transfer backup roller 32, a cleaning backup roller 33, and a tension roller 34. Here, as the secondary transfer backup roller 32 is rotationally driven, the intermediate transfer belt 30 is circulated (rotated) in the direction indicated by the arrow in the figure.
The four primary transfer rollers 31 sandwich the intermediate transfer belt 30 between them and the respective photoconductors 5 to form a primary transfer nip. A power source is connected to the four primary transfer rollers 31, and at least one of a predetermined DC voltage (DC) and AC voltage (AC) is applied to each of the primary transfer rollers 31. ing.

The secondary transfer roller 36 sandwiches the intermediate transfer belt 30 with the secondary transfer backup roller 32 to form a secondary transfer nip. A power source is also connected to the secondary transfer roller 36 so that at least one of a predetermined DC voltage (DC) and AC voltage (AC) is applied to the secondary transfer roller 36.
The belt cleaning device 35 has a cleaning brush and a cleaning blade which are arranged so as to contact the intermediate transfer belt 30. The belt cleaning device 35 includes a waste toner transfer hose and is connected to a waste toner container.

A bottle accommodating portion 15 is provided on the top of the printer 1 main body, and four toner bottles 2 (Y, M, C, K) accommodating replenishment toner are detachably attached to the bottle accommodating portion 15. Has been done. A toner replenishing unit 40, which will be described later, is provided between the four toner bottles 2 (Y, M, C, K) and the four developing devices 7, and each toner bottle 2 is connected via the toner replenishing unit 40. Toner is supplied from (Y, M, C, K) to each developing device 7.
At the lower part of the main body of the printer 1, there are provided a paper feed tray 10 that contains paper P as a recording medium, a paper feed roller 11 that carries out the paper P from the paper feed tray 10, and the like. As the recording medium, in addition to plain paper, thick paper, postcard, envelope, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet and the like can be used. Further, a manual sheet feeding mechanism may be provided as a configuration for feeding the recording medium.

Inside the main body of the printer 1, a conveyance path R is provided for ejecting the paper P from the paper feed tray 10 through the secondary transfer nip to the outside of the apparatus. A pair of registration rollers 12 is provided on the transport path R upstream of the position of the secondary transfer roller 36 in the sheet transport direction as a transport unit that transports the sheet P to the secondary transfer nip.
Further, a fixing device 20 for fixing the unfixed image transferred to the sheet P is disposed downstream of the position of the secondary transfer roller 36 in the sheet conveying direction. A paper discharge roller pair 13 for discharging the paper P out of the apparatus is provided on the downstream side of the fixing device 20 in the paper carrying direction of the carrying path R. Further, a paper discharge tray 14 for stocking the paper P discharged to the outside of the apparatus is provided on the upper surface of the main body of the printer 1.

The basic operation of the printer 1 shown in FIG. 1 is as follows.
When the image forming operation is started, each photoconductor 5 in each image forming unit 4 (Y, M, C, K) is rotationally driven in the clockwise direction in FIG. The surface of 5 is uniformly charged to a predetermined polarity by each charging device 6.
Laser light is irradiated from the exposure device 9 onto the surface of each of the charged photoconductors 5 to form an electrostatic latent image on the surface of each of the photoconductors 5. At this time, the image information exposed on each photoconductor 5 is monochromatic image information obtained by dividing a desired full-color image into color information of yellow, magenta, cyan, and black. In this way, the toners are supplied to the electrostatic latent images formed on the photoconductors 5 by the developing devices 7, so that the electrostatic latent images are visualized as toner images (visualized images). ) Is done.

Further, when the image forming operation is started, the secondary transfer backup roller 32 is rotationally driven in the counterclockwise direction in FIG. 1, and the intermediate transfer belt 30 is circulated in a direction indicated by an arrow “A” in FIG. Let Then, to each of the primary transfer rollers 31, a constant-voltage-controlled or constant-current-controlled voltage having a polarity opposite to the charging polarity of the toner is applied. As a result, a transfer electric field is formed in the primary transfer nip between each primary transfer roller 31 and each photoconductor 5.
After that, when the toner images of the respective colors on the photoconductors 5 reach the primary transfer nip as the photoconductors 5 rotate, the toner images on the photoconductors 5 are transferred by the transfer electric field at the primary transfer nip. The images are transferred onto the intermediate transfer belt 30 so as to be sequentially superposed. In this way, a full-color toner image is carried on the surface of the intermediate transfer belt 30.

The toner on the photoconductor 5 that has not been completely transferred to the intermediate transfer belt 30 is removed by each cleaning device 8. Then, the surface of each of the photoconductors 5 is neutralized by the static eliminator, and the surface potential is initialized.
At the lower part of the main body of the printer 1, the paper feed roller 11 starts to rotate and the paper P is sent out from the paper feed tray 10 to the transport path R. The paper P sent out to the transport path R is sent to the secondary transfer nip between the secondary transfer roller 36 and the secondary transfer backup roller 32, with the timing being measured by the registration roller pair 12. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 30 is applied to the secondary transfer roller 36, whereby a transfer electric field is formed in the secondary transfer nip. There is.

After that, when the toner image on the intermediate transfer belt 30 reaches the secondary transfer nip as the intermediate transfer belt 30 orbits, the toner image on the intermediate transfer belt 30 is generated by the transfer electric field at the secondary transfer nip. Are collectively transferred onto the paper P. At this time, the residual toner on the intermediate transfer belt 30 that could not be transferred to the paper P is removed by the belt cleaning device 35, and the removed toner is conveyed to the waste toner container and collected.
After that, the paper P is conveyed to the fixing device 20, and the toner image on the paper P is fixed on the paper P by the fixing device 20. Then, the paper P is discharged to the outside of the apparatus by the paper discharge roller pair 13 and is stocked on the paper discharge tray 14.

  The above description is for the image forming operation when forming a full color image on a sheet, but a single color image is formed using any one of the four image forming units 4 (Y, M, C, K). It is also possible to form a two-color or three-color image by using two or three image forming units 4.

  Next, the toner replenishing unit 40, which is a toner conveying device for conveying toner from each toner bottle 2 (Y, M, C, K) to each developing device 7, will be described. The toner replenishing unit 40 is provided for each toner bottle 2 (Y, M, C, K), but since it has the same configuration, the suffix (Y, M, C, K) will be used. Will be omitted.

FIG. 2 is a perspective view of the vicinity of the toner supply unit 40 included in the printer 1.
In the printer 1 of the present embodiment, the transfer device 3, which is an intermediate transfer unit, is disposed between the toner bottle 2 and the developing device 7, so that the developing device 7 and the toner bottle 2 are separated in a substantially vertical direction. It is arranged. Therefore, in the printer 1 of the present embodiment, as shown in FIG. 2, the vertical transport unit 41, which is the first transport pipe for transporting the toner filled in each toner bottle 2 to the developing device 7, It is provided between the toner bottle 2 and the developing device 7. The toner conveyed from the toner bottle 2 to the upper end of the vertical conveyance unit 41 via the conveyance unit 43, which is a second conveyance pipe described later, falls in the vertical conveyance unit 41 by gravity, and the lower end of the vertical conveyance unit 41. The toner is discharged to the developing device 7 from the toner discharge port 41a provided in the.

FIG. 3 is a perspective view showing an overall configuration of the toner supply unit 40 and the developing device 7.
The developing device 7 of the present embodiment can be pulled out from the main body of the printer 1 and is provided with an intake port 7a for taking in toner. As shown in FIG. 3, when the developing device 7 is mounted on the main body of the device, the toner discharge port 41a of the vertical transport unit 41 and the intake port 7a of the developing device 7 are connected.

Next, the toner conveyance from the toner bottle 2 to the developing device 7 will be described in detail.
FIG. 4 is a sectional view of a main part of the toner replenishing unit 40.
As shown in FIG. 4, the toner bottle 2 is connected to a carrying section 43 installed in the main body. The toner dropped from the toner bottle 2 by gravity or driven to rotate is stored in the transport unit 43 through the receiving port 43 a of the transport unit 43. A screw 44, which is a rotary transport unit, is provided in the transport unit 43, and the toner transported in the transport unit 43 is transported to the downstream of the transport unit 43 by the rotation of the screw 44.

  The vertical transport unit 41 is connected downstream of the transport unit 43 in the toner transport direction. When the toner transported by the screw 44 is transported to the opening of the vertical transport unit 41, the toner drops into the vertical transport unit 41 as shown by an arrow B in the figure.

  In recent years, there has been a tendency for the temperature inside the machine to increase due to the reduction of the space of the apparatus and the adoption of environmentally friendly toner mainly for low-temperature fixing. As a result, the toner deteriorates in fluidity with respect to temperature, and the toner or the like that freely falls due to its own weight and adheres to the side wall may increase in viscosity and adhere to the spot.

FIG. 9 is a sectional view of a main part of the conventional toner supply unit 140.
Therefore, in order to prevent the toner that has fallen freely from adhering to the side wall inside the vertical conveyance unit, conventionally, as shown in FIG. 9, a coil spring 145 having one end fixed to the screw 44 is provided above the vertical conveyance path 141. This coil spring 145, which has been known as a toner transporting device suspended in a vertical direction, moves up and down by the rotation of the screw 44 to scrape off the toner adhering to the side wall of the vertical transporting path 141.
However, in the coil spring 145, as described above, the toner on the coil spring may adhere to the side wall of the vertical transport path. Further, since it is not possible to contact all the wall surfaces of the vertical transport path, there is a possibility that a portion where the toner remains attached to the side wall may occur.

Therefore, in the toner replenishing unit 40 of the present embodiment, as shown in FIG. 4, the swing plate member 45, which is a plate member that swings in the vertical transport unit 41 and contacts the inner wall surface of the vertical transport unit 41, is provided. Prepared The oscillating plate member 45 is arranged such that the side surface 45 a of the oscillating plate member 45 is parallel to the toner carrying direction in the vertical carrying section 41.
A swing plate member 45 is held in a part of the screw 44 facing the opening of the vertical transport unit 41 connected to the transport unit 43, and the swing plate member 45 is swung by the rotation of the screw 44. The link unit 46, which is a mechanism, is provided. The link portion 46 is arranged downstream of the opening of the vertical transport portion 41 in the toner transport direction of the screw 44.

Hereinafter, the swing plate member 45 and the link portion 46 will be described in detail.
FIG. 5 is an explanatory diagram of a connecting portion between the link portion 46 and the swing plate member 45 of the toner replenishing unit 40.
FIG. 6 is a perspective view showing an attachment state of the link portion 46 and the swing plate member 45.
As shown in FIG. 5A, the link part 46 includes two support parts 46b, which are two support members provided by dividing a part of the rotary shaft 44a of the screw 44, and the two support parts 46b. And a columnar portion 46a having a columnar shape that is long in the direction of the rotation axis 44a of the screw 44 supported by. In the present embodiment, the columnar portion 46a is supported by the two supporting portions 46b at both ends at a position that is flush with the outer circumferential arc of the screw 44.

  Further, as shown in FIG. 5B, a notched cylindrical portion 45d is provided at one end of the rocking plate member 45. As shown in FIG. 6, the rocking plate member 45 is held by the screw 44 by fitting the cylinder portion 45 d into the cylinder portion 46 a of the link portion 46 provided on the screw 44. The cylindrical portion 45d is rotatable with respect to the cylindrical portion 46a of the link portion 46, and when the screw 44 is rotated, the swing plate is not moved in the vertical transport portion 41 without tilting the side surface 45a of the swing plate member 45. The member 45 can be swung.

FIG. 7 is a diagram illustrating the configuration of the rocking plate member 45.
The oscillating plate member 45 of the present embodiment has a length in the width direction of the vertical conveying unit 41 on the side surface 45 a of the oscillating plate member 45 at the end face of the oscillating plate member 45 on the upstream side in the toner conveying direction in the vertical conveying unit 41. Has an inclined portion 45b that becomes longer from the upstream side to the downstream side in the toner transport direction. The above-mentioned cylindrical portion 45d is provided ahead of the inclined portion 45b, and a connecting portion 45c between the inclined portion 45b and the cylindrical portion 45d is provided.

The length of the connecting portion 45c in the toner transport direction is oscillated when the cylindrical portion 45d of the oscillating plate member 45 is fitted in the cylindrical portion 46a of the link portion 46 and is positioned at the highest position in the vertical direction. The length of the inclined portion 45b of the plate member 45 is set so as not to project to the side of the transport unit 43. As described above, since the inclined portion 45b does not jump out to the side of the transport unit 43, it is possible to make it difficult for the swing plate member 45 to interfere with the transport of the toner in the transport unit 43.
Further, the oscillating plate member 45 of the present embodiment is formed of a thin, light, and hard member such as a PET member, but not limited to this, other materials can be used.

Next, the movement of the rocking plate member 45 will be described.
FIG. 8 is an explanatory view of the operating state of the link portion as seen from the axial direction of the screw.
As shown in FIGS. 8A to 8C, in the movable range of the columnar portion 46 a of the link portion 46, the side surface 45 a of the rocking plate member 45 held by the link portion 46 becomes the inner wall 41 b of the vertical transport portion 41. It is within the range of contact. Accordingly, when the columnar portion 46a of the link portion 46 rotates with the rotation of the screw 44, the side surface 45a of the swing plate member 45 can always contact the inner wall 41b of the vertical transport unit 41. As a result, it is possible to prevent the toner conveyed by its own weight from adhering to the inner wall 41b of the vertical conveyance unit 41.

  Further, regarding the conveyance of toner in the vertical conveyance unit 41, only the thickness of the oscillating plate member 45 blocks the toner conveyance direction. Therefore, compared with the case where a spring is used as the cross-linking prevention member, it is less likely to hinder the toner conveyance.

  What has been described above is an example, and unique effects are obtained for each of the following aspects.

(Aspect A)
A powder conveying pipe such as a vertical conveying unit 41 that guides the powder to its destination by its own weight, and an oscillating plate member that prevents the powder bridging due to the adhesion of the powder on the inner wall by contacting the inner wall of the powder conveying pipe. In a powder conveying device such as a toner replenishing unit 40 including a bridge preventing member such as 45, the bridge preventing member is a plate member such as an oscillating plate member 45 movable in the powder conveying pipe. The side surface of the member is parallel to the powder conveying direction in the powder conveying pipe.

  In this aspect, since the side surface of the plate member is parallel to the powder carrying direction in the powder carrying pipe, the place where the carried powder is placed on the plate member is on the upstream side in the powder carrying direction of the plate member. It can be only the end face. Therefore, as compared with the conventional device that uses the spring coil as the bridging prevention member, the range of the powder on the contact member during the powder conveyance can be narrowed. It is possible to prevent the powder on the inner surface of the powder carrier pipe from adhering to the inner wall surface of the powder carrier pipe.

  Further, since the side surface of the plate member is parallel to the powder carrying direction in the powder carrying tube, it is possible to prevent the powder carrying from being disturbed.

(Aspect B)
In Aspect A, a first transfer pipe that is the powder transfer pipe such as the vertical transfer unit 41, and a transfer unit 43 that is connected to the first transfer unit and transfers powder by a rotary transfer member such as a screw 44. And a second transport unit such as the above, and a movable mechanism such as a link unit 46 that moves the plate member by rotation of the rotary transport member.

(Aspect C)
In Aspect B, the movable mechanism is provided by dividing a part of a rotary shaft of the rotary transport member facing the opening of the first transport pipe connected to the second transport pipe such as the transport unit 43. Two supporting members such as the two supporting portions 46b that are provided, and a columnar portion 46a that is long in the rotation axis direction and has both ends supported by the two supporting members at positions that are flush with the outer circumferential arc of the rotary conveying member. A cylindrical portion and a cylindrical portion such as a cylindrical portion 45d provided at one end of the plate member such as the oscillating plate member 45 and rotatably attached to the cylindrical portion are provided. The plate member is swung in the first transport pipe.

(Aspect D)
In any one of Modes A to C, the end surface of the plate member such as the oscillating plate member 45 on the upstream side in the powder conveying direction in the first conveying pipe such as the vertical conveying unit 41 and the side surface of the plate member. It is characterized in that it has an inclined portion such as an inclined portion 45b such that the length in the width direction of the first conveying pipe becomes longer from the upstream side to the downstream side in the conveying direction.
In this aspect, as described in the above embodiment, it is possible to make it difficult for the transported powder to ride on the end surface of the plate member on the upstream side in the transport direction.

(Aspect E)
In mode C, the first transfer on the side surface of the plate member is performed on the end surface of the plate member such as the rocking plate member 45 on the upstream side in the powder transfer direction in the first transfer pipe such as the vertical transfer unit 41. The portion has an inclined portion such as an inclined portion 45b in which the length in the width direction increases upstream in the conveying direction toward the downstream, and when the plate member swings, the inclination is formed only in the first conveying portion. It is characterized in that the department moves.
In this aspect, as described in the above embodiment, it is possible to make it difficult for the plate member to hinder the toner conveyance.

(Aspect F)
An image carrier such as a photoconductor 5 carrying a latent image, a developing unit such as a developing device for developing the latent image carried on the image carrier with a developer, and a developer carrying the developer to the developing unit. In the image forming apparatus such as the printer 1 including the conveying means, the powder conveying apparatus according to any one of Aspects A to E is used as the developer conveying means.

1 Printer 2 Toner Bottle 3 Transfer Device 5 Photosensitive Member 7 Developing Device 8 Cleaning Device 40 Toner Replenishing Unit 41 Vertical Conveying Section 41a Toner Discharge Port 41b Inner Wall 43 Conveying Section 43a Port 44 Screw 44a Rotating Shaft 45 Oscillating Plate Member 45a Side 45b Tilt Part 45c Connection part 45d Cylindrical part 46 Link part

JP-A-2000-284594

Claims (5)

In a powder carrying device provided with a powder carrying pipe for guiding powder to a carrying destination by its own weight, and a bridge preventing member provided in the powder carrying pipe , the bridge preventing member has an inner wall of the powder carrying pipe. Is a plate member that is movable in the powder transfer pipe by contacting the above, the side surface of the plate member is parallel to the powder transfer direction in the powder transfer pipe , and The end face of the plate member on the upstream side in the conveying direction has an inclined portion such that the length in the width direction of the powder conveying pipe on the side surface of the plate member increases from the upstream side to the downstream side in the conveying direction. And a powder transfer device.   The powder carrying device according to claim 1, wherein the first carrying pipe is the powder carrying pipe, and the second carrying pipe is connected to the first carrying pipe and carries the powder by a rotary carrying member. And a movable mechanism that moves the plate member by rotation of the rotary conveying member. 3. The powder carrying device according to claim 2, wherein the movable mechanism divides a part of a rotary shaft of the rotary carrying member facing an opening of the first carrying pipe connected to the second carrying pipe. And two columnar members, both ends of which are supported by the two columnar members at positions that are aligned with the outer circumferential arc of the rotary conveyance member by the two columnar members, and one end of the plate member. And a cylindrical portion rotatably attached to the cylindrical portion, wherein the plate member is swung in the first conveying pipe by rotation of the rotary conveying member. Equipment . In the powder conveying device according to 請 Motomeko 2 or 3, prior to during swinging of Kiban member, the powder conveying device, characterized in that said inclined portion only at the first conveying tube to move. An image forming apparatus including an image carrier for carrying a latent image, a developing unit for developing the latent image carried on the image carrier with a developer, and a developer carrying unit for carrying the developer to the developing unit. in the image forming apparatus characterized by using a powder conveying apparatus of claim 1 to 4 any one as the developer conveying unit.

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