JP2001042627A - Toner transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner transport device which almost uniformly transports toner to a desired spot without deviation. SOLUTION: In this toner transport device, three toner discharging holes 90a, 90b and 90c is kept closed, at the initial stage of starting the transport of the toner, by an opening/closing door 92. Accordingly, the toner transported through a transport groove 90 is intercepted by the opening/closing door 92 and is transported without being discharged from the three toner discharging holes 90a, 90b and 90c. The toner discharging holes 90a, 90b and 90c are opened by making 3 positions of the toner discharging holes 90a, 90b and 90c align with 3 openings 92a, 92b and 92c by shifting the opening/closing door 92 in timings such that the transport groove 90 is filled with the toner moreover transported through the transport groove 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner conveying device incorporated in an image forming apparatus such as a copying machine, a printer, a facsimile or the like employing an electrophotographic system.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus for forming an image on a recording medium using a toner (developer) has been widely used.

Referring to FIG. 8, an example of a conventional image forming apparatus using an electrophotographic method will be described.

FIG. 8 is a schematic diagram showing an example of a conventional image forming apparatus.

[0005] The image forming apparatus 10 includes a motor (not shown).
The photosensitive drum 12 is rotated in a direction indicated by an arrow A in FIG. A main charger 14 is arranged to face the photosensitive drum 12, and the photosensitive drum 12 is uniformly charged by corona discharge from the main charger 14. The uniformly charged photosensitive drum 12 is irradiated with light (document exposure) 16 carrying information of an image recorded on a document (not shown), and an electrostatic latent image is formed on the photosensitive drum 12. You. A developing device 18 that develops an electrostatic latent image is arranged downstream of the position where the photosensitive drum 12 is irradiated with the document exposure in the rotation direction of the photosensitive drum 12. The developing device 18 has a developing sleeve 20 that is rotated in the direction of arrow B by a motor (not shown), and toner (developer) is supplied from the developing sleeve 20 to the photosensitive drum 12 so that the photosensitive drum 1
2, a toner image (developed image) is formed. The developing device 1
A hopper 19 containing toner is disposed on the top of the hopper 8.

[0006] The registration rollers 22 and 2 are synchronized with the moving speed of the toner image formed on the photosensitive drum 12 at timing.
4 rotate in the directions of arrows C and D, respectively, and a recording medium (not shown) such as recording paper is guided by the guide section 26 and conveyed toward the transfer charger 28. The toner image on the photosensitive drum 12 is transferred to the recording medium that has reached the transfer charger 28. The recording medium onto which the toner image has been transferred is placed on the separation charger 30.
Is separated from the photosensitive drum 12. Separate charger 3
A cleaning device (cleaner unit) 34 including a cleaning blade 32 is arranged downstream of the photosensitive drum 12 in the rotation direction of the photosensitive drum 12. The toner remaining on the photosensitive drum 12 after the transfer is scraped off by the cleaning blade 32. The scraped toner is conveyed and stored in a waste toner box 72 (see FIG. 13). The waste toner box 72 is mainly collected or replaced by a service person, and the capacity of the waste toner box is large in order to reduce the frequency of such collection and replacement.

A pre-exposure device 36 is disposed downstream of the cleaning device 34 in the rotation direction of the photosensitive drum 12, and the pre-exposure device 36 removes the residual potential on the photosensitive drum 12. On the other hand, the recording medium on which the toner image has been transferred is guided by the guide portions 38 and 40 and is conveyed to the fixing device 42. The fixing device 42 has a fixing roller 46 rotating in the direction of arrow F and a pressure roller 44 rotating in the direction of arrow E. The recording medium is fixed by the fixing device 42, and then the recording medium is ejected outside the apparatus, and one copy cycle is completed.

As described above, in the electrophotographic image forming apparatus 10, since a visible image is obtained using toner, a toner conveying device for conveying toner is incorporated. Examples of the toner conveying device include a toner supply device that supplies toner from the hopper 19 to the developing device 18.

Referring to FIGS. 9 to 12, hopper 1
A description will be given of a toner supply device for supplying toner from 9 to the developing device 18.

FIG. 9 is a perspective view showing a schematic configuration in the case where a toner conveying device is used as a toner supply device for supplying toner from a hopper to a developing device, and FIG. 10 is a toner supply device removed from the developing device. FIG. FIG.
1 is a side view schematically illustrating a schematic configuration of a toner supply device, and FIG. 12 is a side view schematically illustrating a transport groove in which toner is accumulated.

The toner supply device 50 is mounted above the developing device 18. The toner supply device 50 includes a transport screw 56 including a shaft portion 52 extending along the developing sleeve 20 and a blade surface 54 spirally formed on an outer peripheral surface of the shaft portion 52. The transport screw 56 is accommodated in a “U” -shaped transport groove 58 whose inner diameter is substantially equal to the radius of the blade surface 54, and toner is transported inside the transport groove 58. The shaft 52 is connected to the developing sleeve 20 via a gear (not shown), and rotates together with the developing sleeve 20 by a driving force from the main body of the image forming apparatus 10.

As shown in FIG. 10, a drop port 58a through which toner falls is formed in the side wall of the conveyance groove 58 in the longitudinal direction. As shown in FIG. 11, the lower end of the falling port 58 a is located at a portion of the side wall of the transport groove 58 that is lower than the horizontal line 60 by an angle Θ. The angle Θ increases toward the downstream side in the toner transport direction (the direction of arrow G).
That is, the falling port 58a becomes wider toward the downstream side in the toner transport direction. The downstream portion of the falling port 58a in the toner transport direction extends to the bottom wall of the transport groove 58 so that all the toner transported to this portion does not fall and cause toner clogging. .

The manner in which the toner supplied from the hopper to the toner supply device is transported to the developing device will be described.

The toner from the hopper 19 (see FIG. 8)
A predetermined amount is supplied to the most upstream portion of the transport groove 58 in the toner transport direction. The supplied toner is conveyed inside the conveyance groove 58 toward the downstream side in the toner conveyance direction with the rotation of the conveyance screw 56. As shown in FIG. 12, the toner being conveyed is conveyed in the conveying groove 58 in a state of being raised to a height h determined by the conveying force of the conveying screw 56, the gravitational force, the amount of toner, the fluidity of the toner, and the like. . When the toner reaches the drop port 58a, when the lower end of the drop port 58a is located lower than the top of the toner,
The toner falls into the developing unit 18 from the drop port 58a. The amount of toner falling is determined mainly based on the difference between the top of the toner and the falling port 58a.

The toner that has not fallen from the falling port 58a is transported further downstream in the transport direction. When the toner being conveyed falls from the drop port 58a, the amount of the dropped toner decreases, and the height h of the toner also decreases. However, as shown in FIG. 11, the angle Θ between the horizontal line 60 and the lower end of the dropout 58a increases downward toward the downstream side in the transport direction. Therefore, even if the height h of the toner decreases, The toner falls from the falling port 58a.

As described above, the toner being conveyed is gradually dropped into the developing device 18 from the falling port 58a and is stored.
Therefore, the toner can be uniformly dropped over the entire width of the developing device 18 by setting the inclination of the transport groove 58 and the position of the lower end of the drop port 58a to appropriate values. Also,
As described above, since the portion of the falling port 58a on the downstream side in the toner conveying direction extends to the bottom wall of the conveying groove 58, all the toner conveyed to the most downstream side falls into the developing device 18, and The transport groove 58 is not clogged by the toner.

Next, with reference to FIG. 13, a description will be given of a waste toner conveying device for conveying the toner scraped off by the cleaning blade to a waste toner box.

FIG. 13 is a perspective view schematically showing a waste toner conveying device.

The toner scraped off by the cleaning blade 32 is transported to the connecting pipe 70 by a transport screw (not shown) arranged at the bottom of the cleaning device 34. The upper end of the connecting pipe 70 is connected to the most downstream portion in the transport direction of the transport screw. On the other hand, the lower end of the connection pipe 70 is connected to a waste toner box 72 disposed below the cleaning device 34. For this reason, the toner transported to the transport screw falls inside the connecting pipe 70 and is stored in the waste toner box 72.

[0020]

As described above, the toner conveying device is used in an image forming apparatus. However, the conventional toner conveying device has the following problems.

First, the developing device 18 (see FIGS. 9 and 10)
A toner transport device for transporting toner to the printer will be described.

The width of the developing device 18 is at least the maximum sheet passing width in the image forming apparatus 10. Hopper 1
9 (see FIG. 8) must be replenished into the developing device in a uniform amount over the width of the developing device. If the replenishment amount is not uniform over the entire width of the developing device, the distribution of the amount of toner inside the developing device 18 is not uniform, and the amount of toner supplied to the photosensitive drum 12 may also vary. Due to this variation, a difference in density of a recorded image may occur, or fog may occur, thereby deteriorating the image quality.

In the toner conveying device 50 described with reference to FIGS. 9 to 12, the distribution of the amount of toner supplied to the developing device 18 in the width direction of the developing device is determined by the position and size of the dropout 58a, and The height h of the toner in the transport groove 52 (FIG. 12)
Reference). However, for example, in a high-humidity environment and a low-humidity environment, the amount of toner absorbed changes and the fluidity changes. When the fluidity of the toner fluctuates in this manner, the height h of the toner fluctuates, and the amount of the toner that falls from a predetermined position of the fall port 58a also fluctuates. For example, when the toner is dry in a low humidity environment, the fluidity of the toner is good.
A predetermined amount of toner always falls from 8a, and the toner can be supplied uniformly in the width direction of the developing device. On the other hand, when the toner absorbs moisture in a high-humidity environment and becomes poor in fluidity or easily aggregates, the height h of the toner becomes higher than in a low-humidity environment. In this case, since a predetermined amount of toner does not drop from the drop port 58a, the toner may not be supplied uniformly in the width direction of the developing device.

Consider a case where toner is supplied to the developing device 18 containing no toner, such as when a new image forming apparatus 10 (see FIG. 8) is installed.

In such a case, in order to prevent the toner from being scattered, a special operation mode such as an installation mode is provided instead of directly supplying the toner to the developing device outside the apparatus, and the developing device 18 is provided with the image forming device 10. The toner is supplied from the hopper 19 in a state where the toner is attached to the hopper 19. When the toner is supplied in such a state, the toner is supplied in order from the front side portion (the portion near the hopper 19) of the developing device 18 by the transport screw 56. Therefore, the developing device 18
A large amount of toner is supplied to the front side, and only a small amount of toner is supplied to the back side (part far from the hopper 19), and the toner is biased inside the developing device 18.

As described above, when the toner is biased inside the developing device 18 from the initial state in which the new image forming apparatus 10 is installed, the above-described deterioration of the image quality occurs from the beginning. Such bias of the toner is particularly likely to occur in a CAD output electrophotographic plotter or a large-size copying apparatus in which the width of the developing device is close to about 1 m, and causes deterioration in image quality.

Next, with reference to FIG. 14, a problem when the toner scraped off by the cleaning blade 32 shown in FIG. 13 is transported to the waste toner box 72 will be described.

FIG. 14 is a schematic view showing the waste toner stored in the waste toner box.

In the waste toner box 72, usually, waste toner is dropped and stored from above. In this case, as shown in FIG. 14, when the waste toner box 72 is formed in a horizontally long shape having a large bottom area, the waste toner 72a is piled up at a place where the waste toner 72a falls, and the waste toner box 72 is stored in the waste toner box 72. There is a problem that it is difficult to uniformly house 72a. This problem can be solved by forming the waste toner box 72 in a vertically long shape having a small bottom area. However, it is often difficult to secure a space for incorporating such a vertically long waste toner box inside the image forming apparatus 10 (FIG. 8).

The present invention has been made in view of the above circumstances, and has as its object to provide a toner transport device that transports toner substantially uniformly to a target location without bias.

[0031]

According to a first aspect of the present invention, there is provided an image forming apparatus for supplying a toner to an electrostatic latent image formed on an image carrier to obtain a toner image. In a toner transport device that transports toner from a predetermined first location to a predetermined second location, (1) one toner to which toner is transported, wherein the first location and the second location are formed A transport path; (2) a toner supply port formed in the first location to which toner is supplied; and (3) a plurality of toner discharge apertures formed in the second location and discharging toner. And (4) an opening / closing door for opening and closing the plurality of toner discharge holes.

Here, (5) the opening and closing door may open and close the plurality of toner discharge holes simultaneously.

(6) The opening and closing door may open and close the plurality of toner discharge holes independently of each other.

(7) The toner transport path is
(7-1) Toner conveyance that has a shaft portion extending in the direction in which the conveyance path extends and a wing surface spirally formed on the outer peripheral surface of the shaft portion, and conveys toner by rotating the shaft portion. And (7-2) a conveying groove in which the toner conveying screw is accommodated and in which the toner passes.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a toner conveying device according to the present invention will be described with reference to the drawings.

An image forming apparatus incorporating the toner conveying device of the present invention has the same basic configuration as the conventional image forming apparatus shown in FIG.

First, a first embodiment of the toner conveying device will be described with reference to FIG.

FIG. 1 is a perspective view showing a first embodiment of the toner conveying device.

The toner conveying device 80 includes a “U” -shaped conveying groove 90 through which the toner passes, and a toner conveying screw 100 housed in the conveying groove 90.

The toner conveying direction (arrow H) in the conveying groove 90
A toner supply port 98 to which the toner is supplied is formed at the most upstream side in the direction (i.e., direction). The place where the toner supply port 98 is formed is an example of the first place according to the present invention. On the other hand, three toner discharge holes 90a, 90b, and 90c of the same size are formed in the transfer groove 90 from the middle flow side portion to the downstream side in the toner transfer direction, from which all the transferred toner is discharged (falls). Have been.

From the toner discharge hole 90a to the toner discharge hole 90
b, the distance from the toner discharge hole 90b to the toner discharge hole 90c is Lb, and the toner discharge hole 9
Assuming that the distance from 0c to the toner supply port 98 is Lc, three toner discharge holes 90a, 90b, 90c are formed at equal intervals at a position where La = Lb = Lc. Three
The positions of the two toner discharge holes 90a, 90b, 90c are respectively the front part, the central part, and the second place where the toner is discharged.
Corresponds to the rear. That is, the three toner discharge holes 90a, 90
0b and 90c are almost uniformly distributed in the second place where the toner is discharged.

The transport screw 100 includes a shaft portion 100a extending in the toner transport direction (the direction of arrow H) and a shaft portion 100a.
Is provided with a spirally formed blade surface 100b on the outer peripheral surface. The radius of the blade surface 100b is substantially equal to the inner diameter of the semicircular bottom wall of the transport groove 90. The diameter of the blade surface 100b is substantially equal to the depth of the transport groove 90. The transport groove 9 described above
0 and the conveying screw 100 constitute an example of a conveying path according to the present invention. Further, an upstream portion of the shaft portion 100 a in the toner transport direction protrudes to the outside of the transport groove 90 through the toner supply port 98. The gear 100c is fixed to the protruding portion. By rotating a gear 100c by rotating a drive motor (not shown), the shaft portion 100a rotates at a constant speed to rotate the blade surface 100b. With this rotation, the toner supplied to the toner supply port 98 is transported in the toner transport direction through the transport groove 90.

A "U" shaped opening / closing door 92 covers the transport groove 90 from below so as to cover the outer peripheral surface thereof. The opening / closing door 92 has three openings 92 of the same size at an interval of a distance La.
a, 92b and 92c are formed. The size of these three openings 92a, 92b, 92c is
0a, 90b and 90c are almost the same size. The opening / closing door 92 is moved by an arrow I by a drive motor (not shown).
Move in the direction.

Referring to FIG. 2, the opening and closing of the toner discharge hole will be described.

FIG. 2 is a schematic diagram showing a state in which the toner opening / closing hole is opened / closed.

When the door 92 moves in the direction of arrow I,
As shown in (A) and (B), three openings 92a and 92
b, 92c are three toner discharge holes 90a, 90b, 90
c, three toner discharge holes 9
Since 0a, 90b and 90c are closed, no toner is discharged from these three toner discharge holes 90a, 90b and 90c. On the other hand, as shown in (A) and (C), three openings 92a, 92b and 92c
0a, 90b, and 90c, 3
Since two toner discharge holes 90a, 90b, 90c are opened,
The toner can be discharged from these three toner discharge holes 90a, 90b, 90c. Thus, in the toner conveying device 80, by moving the opening / closing door 92 in the direction of the arrow I,
The three toner discharge holes 90a, 90b, 90c can be opened at the same time, or they can be closed at the same time.

The operation (toner conveying operation) for conveying the toner by the toner conveying device 80 will be described.

The toner conveying operation is started by rotating the gear 100c and starting to rotate the shaft 100a. When toner is supplied to the toner supply port 98 from a hopper (not shown) or the like, the supplied toner is transported downstream in the toner transport direction (the direction of arrow H) by the blade surface 100b that rotates together with the shaft portion 100a. You.

When the opening / closing door 92 is at the position shown in FIG. 2B, the three toner discharge holes 90 are provided as described above.
a, 90b, 90c are closed by an opening / closing door 92. For this reason, the toner conveyed through the conveyance groove 90 is
2 and three toner discharge holes 90a, 90b, 90
The paper is transported without being discharged from c.

The toner is further transported through the transport groove 90, and the opening / closing door 92 moves at a timing such that the transport groove 90 is filled with the toner, reaches the position shown in FIG. When the door 92 is at this position, the positions of the three toner discharge holes 90a, 90b, 90c coincide with the positions of the three openings 92a, 92b, 92c of the door 92 as described above. Therefore, the toner discharge holes 90a, 90b, 9
0c is opened and the toner conveyed through the conveyance groove 90 is supplied to the three toner discharge holes 90a, 90b, 90c and the three openings 9a.
It is discharged through 2a, 92b, 92c.

Here, the three toner discharge holes 90a, 90
Consider the toner amount W discharged from b, 90c.

The total amount Wa of toner discharged from the toner discharge port 90a is the amount of toner existing in a portion between the toner discharge port 90b and the toner discharge port 90a in the transport groove 90. The toner existing upstream of this portion in the toner transport direction is the toner outlet 90b or the toner outlet 90c.
From the toner outlet 90a.
Do not reach. Similarly, the total amount Wb of toner discharged from the toner discharge port 90b is the amount of toner existing in a portion between the toner discharge port 90c and the toner discharge port 90b in the transport groove 90. Since the toner existing on the upstream side in the toner conveyance direction from this portion is discharged from the toner discharge port 90c, the toner does not reach the toner discharge port 90b.

Incidentally, as described above, the distance La from the toner discharge hole 90a to the toner discharge hole 90b and the distance Lb from the toner discharge hole 90b to the toner discharge hole 90c.
Is equal to Therefore, the total amount Wa of the toner is equal to the total amount Wb of the toner. Similarly, the total amount Wc of the toner discharged from the toner discharge hole 90c is equal to the total amount Wb of the toner because the distance Lc is equal to the distance Lb. Therefore, the three toner total amounts Wa, Wb, Wc are equal to each other, and the toner amounts discharged from the three toner discharge holes 90a, 90b, 90c are also equal to each other. That is, the three toner discharge holes 90
Since almost the same amount of toner is discharged from a, 90b, and 90c almost simultaneously, the toner is conveyed almost uniformly to the second place where the toner is discharged. When all of the toner present in the transport groove 90 is discharged as described above, the drive motor (not shown) is stopped to stop the shaft portion 100a, and the toner transport operation ends. When the toner is further transported, the above operation is repeated.

Referring to FIGS. 3 and 4, an example in which the above-described toner conveying device 80 is incorporated in a developing device will be described.

FIG. 3 is a perspective view showing an example in which the toner conveying device shown in FIG. 1 is detached from the developing device. FIG. 4 is a perspective view showing an example in which the toner conveying device shown in FIG. 1 is incorporated in a developing device. In these drawings, the same components as those in FIG. 1 are denoted by the same reference numerals.

A toner conveying device 80 is arranged above the developing device 110. This toner conveying device 80
It functions as a toner supply device that supplies toner to the developing sleeve 112. The toner discharge holes 90a, 90b, 90c of the toner conveying device 80 are located at appropriate positions of the developing device 110, for example, at positions where the width of the developing device 110 is divided at equal intervals. The toner is supplied to the toner supply port 98 from a separately provided hopper (not shown).

In supplying the toner to the developing device 110, first, the toner is supplied from the hopper to the toner supply port 98. The toner supplied to the toner supply port 98 is transferred by the toner transfer device 80 in the toner transfer direction (the direction of arrow H).
And is supplied to the inside of the developing device 110 from the toner discharge holes 90a, 90b, 90c.

At the time of this supply, the toner conveying device 80
As described above, the toner supplied to the toner supply port 98 is transported through the transport groove 90, and the toner is supplied to each toner discharge hole 90.
a, 90b and 90c are simultaneously discharged in equal amounts. As a result, the toner can be supplied almost uniformly into the developing device 110 (which is an example of the second location in the present invention) without bias.

When the developing device 110 is empty, an equal amount of toner is simultaneously passed through the conveying groove 90 to each of the toner discharge holes 90.
a, 90b and 90c. This operation is repeated until a necessary amount of toner is supplied to the developing device 110.
For this reason, each toner discharge hole 90 is provided in the developing device 110.
Since the same amount of toner is repeatedly and simultaneously supplied from a, 90b, and 90c, the initial distribution amount of toner in the developing device 110 can be made substantially uniform. As a result, the amount of toner supplied to the photosensitive drum 12 (see FIG. 8) is also reduced.
2 is substantially uniform in the width direction, so that it is possible to prevent a difference in the density of the recorded image and to prevent the occurrence of fogging, thereby preventing a deterioration in image quality.

Referring to FIG. 5, a second embodiment of the toner conveying device will be described.

FIG. 5 is a perspective view showing a second embodiment of the toner conveying device.

The toner conveying device 120 includes a “U” -shaped conveying groove 130 through which the toner passes, and a toner conveying screw 140 housed in the conveying groove 130.

A toner supply port 138 to which toner is supplied is formed in the most upstream portion of the transport groove 130 in the toner transport direction (the direction of arrow J). This toner supply port 1
The place where 38 is formed is an example of the first place according to the present invention.

On the other hand, from the middle portion to the downstream portion in the toner conveying direction of the conveying groove 130, all of the conveyed toner is discharged (falls), and three toner discharging holes 130a, 130b, and 130 of the same size are discharged. 130c is formed.

From the toner discharge hole 130a to the toner discharge hole 1
The distance from the toner discharge hole 130b to the toner supply hole 138 is Lb, and the distance from the toner discharge hole 130c to the toner supply port 138 is L.
When c is set, three toner discharge holes 130a, 130b, and 130c are formed at equal intervals in a position where La = Lb = Lc. Three toner discharge holes 130a, 130
The positions b and 130c correspond to the front, center, and rear of the second location where the toner is discharged, respectively. That is, the three toner discharge holes 130a, 130b, and 130c are arranged almost uniformly at the second location where the toner is discharged.

The transport screw 140 includes a shaft 140a extending in the toner transport direction (the direction of arrow J) and a shaft 140a.
Is provided with a spirally formed blade surface 140b on the outer peripheral surface. The radius of the blade surface 140b is substantially equal to the inner diameter of the semicircular bottom wall of the transport groove 130. The diameter of the blade surface 140b is substantially equal to the depth of the transport groove 130. The transport groove 130 and the transport screw 140 constitute an example of the transport path according to the present invention.

The upstream portion of the shaft portion 140a in the toner conveyance direction protrudes to the outside of the conveyance groove 130 through the toner supply port 138. The gear 140c is fixed to the protruding portion. By rotating a gear 140c by rotating a drive motor (not shown), the shaft 140a rotates at a constant speed and the blade surface 140
Rotate b. By this rotation, the toner supply port 138
Is transported in the toner transport direction through the transport groove 130.

The transport groove 130 has three toner discharge holes 1
Three opening / closing doors 122a, 122b, 122c which can individually cover 30a, 130b, 130c are covered from below. These three doors 122a, 122b, 122c
Are moved in the direction of arrow K independently of each other by a drive motor (not shown). Thus, the three doors 122
a, 122b, and 122c independently move in the direction of arrow K, so that three toner discharge holes 130a, 130c are formed.
b and 130c are opened and closed independently of each other.

The operation (toner conveying operation) for conveying the toner by the toner conveying device 120 will be described.

The toner conveying operation is started by rotating the gear 140c and starting to rotate the shaft 140a. A toner supply port 138 from a hopper (not shown) or the like.
Is supplied, the supplied toner is transported downstream in the toner transport direction (the direction of the arrow J) by the blade surface 140b that rotates together with the shaft 140a.

As described above, the three doors 122a, 122
By moving 22b and 122c in the direction of arrow K,
The three toner discharge holes 130a, 130b, 130c can be opened and closed independently of each other. In this case, the toner transport operation is the same as in the first embodiment. Here, the operation of moving the three doors 122a, 122b, 122c independently in the direction of arrow K will be described.

As described above, the toner supplied from the hopper or the like is supplied to the three toner discharge holes 130a, 130b,
It is discharged from the open one of 130c. If any one of the portions where toner discharged from the three toner discharge holes 130a, 130b, and 130c accumulates (for example, the toner discharge hole 130a) and the amount of toner is small and the amount of toner is small, the toner discharge hole 130
a with the toner discharge holes 130b and 130c
The control device (not shown) opens and closes the door 122 so as to close the door.
a, 122b, 122c. The opening / closing doors 122a and 122a are set in accordance with the amount of toner discharged and accumulated from the three toner discharge holes 130a, 130b and 130c.
By independently controlling and moving b and 122c,
The toner can be transported almost uniformly without deviation in the target place (second place).

Referring to FIG. 6, the above-described toner conveying device 1
An example in which 20 is incorporated in a developing device will be described.

FIG. 6 is a perspective view showing an example in which the toner conveying device shown in FIG. 5 is incorporated in a developing device. In this figure,
The same components as those in FIG. 5 are denoted by the same reference numerals.

A toner conveying device 120 is arranged above the developing device 110. This toner transport device 120
Functions as a toner supply device that supplies toner to the developing sleeve 112. The toner discharge holes 130a, 130b, and 130c of the toner conveying device 120 are
0, for example, at a position where the width of the developing device 110 is divided at equal intervals. The toner supply port 138 is supplied with toner from a separately provided hopper (not shown).

In supplying toner to the developing device 110, first, toner is supplied from the hopper to the toner supply port 138. The toner supplied to the toner supply port 138 is
The toner conveyance direction (arrow J)
Direction) and the toner discharge holes 130a, 130
b and 130c are supplied to the inside of the developing device 110.
At the time of this supply, in the toner transport device 120, as described above, the toner supplied to the toner supply port 138 is transported through the transport groove 130, and the toner discharge holes 130a, 1
Equal amounts are simultaneously discharged from 30b and 130c. As a result, the toner can be supplied almost uniformly into the developing device 110 (which is an example of the second location in the present invention) without bias.

When the developing device 110 is empty, an equal amount of toner is simultaneously passed through the conveying groove 130 to each of the toner discharge holes 1.
Discharge from 30a, 130b, 130c. This operation is repeated until a necessary amount of toner is supplied to the developing device 110. For this reason, since the same amount of toner is repeatedly and simultaneously supplied into the developing device 110 from the toner discharge holes 130a, 130b, and 130c, the initial distribution amount of the toner in the developing device 110 can be made substantially uniform.

If the distribution of the toner amount is not uniform inside the developing device 110 and the distribution is not uniform,
The three opening / closing doors 122a, 122 are configured such that only one of the toner discharge holes 130a, 130b, 130c corresponding to a portion having a small amount of toner is opened and the other discharge holes are closed.
2b and 122c are moved. As a result, the toner is discharged only to the portion where the toner amount is small, and the unevenness of the toner amount can be eliminated.

As a result, the photosensitive drum 12 (see FIG. 1)
Is also substantially uniform in the width direction of the photosensitive drum 12, so that it is possible to prevent a difference in the density of the recorded image and to prevent the occurrence of fogging, thereby preventing a deterioration in image quality.

Referring to FIG. 7, the above-described toner conveying device 1
An example in which 20 is used as a toner discharge device that conveys toner from a cleaning device 34 (see FIG. 13) to a waste toner box will be described.

FIG. 7 is a perspective view showing an example in which the toner conveying device shown in FIG. 5 is used as a toner discharging device for conveying toner from a cleaning device to a waste toner box.
In this figure, the same components as those in FIG. 5 are denoted by the same reference numerals.

A toner conveying device 120 is disposed above the waste toner box 74. The toner transport device 120 functions as a toner discharge device that discharges waste toner to the waste toner box 74. Toner conveying device 120
The toner discharge holes 130a, 130b, and 130c are located at appropriate positions of the waste toner box 74, for example, at positions where the width of the waste toner box 74 is divided at equal intervals. Also,
The toner supply port 138 is located slightly below the lower end of the connecting pipe 70 (see FIG. 13). The waste toner collected by the cleaning device 34 is supplied to the toner supply port 138 via the connecting pipe 70 (see FIG. 13).

When the waste toner is discharged to the waste toner box 74, first, the waste toner collected by the cleaning device 34 is transferred from the cleaning device 34 to the connecting pipe 7 by a transport screw (not shown) of the cleaning device 34.
It is conveyed to the upper end of 0. The waste toner conveyed to the upper end of the connection pipe 70 falls in the connection pipe 70 and is supplied to the toner supply port 138. The waste toner supplied to the toner supply port 138 is transported by the toner transport device 120 in the toner transport direction (the direction of arrow J).
0a, 130b, and 130c are discharged into the waste toner box 74.

At the time of this discharge, first, only the toner discharge hole 130a (see FIG. 5) is opened, and the other doors 122a, 122c are closed so that the other toner discharge holes 130b, 130c are closed.
122b and 122c are moved. In this way, first, the waste toner is discharged only to the inner part of the waste toner box 74. When a certain amount of waste toner accumulates in the back portion, only the toner discharge hole 130b is opened, and the other toner discharge holes 130a and 130c are closed.
22a, 122b and 122c are moved. As a result, the waste toner is discharged to the center of the waste toner box 74. When a certain amount of waste toner accumulates in this central portion, only the toner discharge hole 130c is opened and the other toner discharge holes 13c are opened.
0a, 130b to close the doors 122a, 122b.
2b and 122c are moved. As a result, the waste toner is discharged to a portion in front of the waste toner box 74. As a result, the waste toner is substantially uniformly stored in the waste toner box 74 without bias.

In each of the above-described embodiments, an example has been described in which a plurality of opening / closing doors appropriately open and close a plurality of toner discharge holes so that an equal amount of toner is conveyed to a second location such as a waste toner box. However, for example, a configuration may be adopted in which a larger amount of toner is discharged from the middle toner discharge hole than from the other discharge holes. With this configuration, a larger amount of toner can be supplied to the central portion in the width direction of the developing device, which consumes a relatively large amount of toner, than the other portions.
Therefore, it is possible to prevent the amount of toner stored in the developing device from being biased. Further, in each of the above embodiments, the number of the toner discharge holes and the opening / closing door is three, but the number is not limited to three and may be four or more, and the toner transport destination (the present invention) The number is determined appropriately according to the size and shape of the second place.

[0086]

As described above, according to the toner conveying apparatus of the present invention, the toner is conveyed to the toner conveying path by closing the opening / closing door so that the toner cannot be discharged from the plurality of toner discharging holes. When substantially the same amount of toner reaches the vicinity of the plurality of toner discharge holes, the opening / closing door is opened, and the toner is discharged from the plurality of toner discharge holes. As a result, substantially the same amount of toner is discharged from the plurality of toner discharge holes at substantially the same time, so that the toner is transported to the second location almost uniformly without bias. When a large amount of toner can be stored in the second location, the above operation is repeated, so that a large amount of toner can be stored almost uniformly in the second location.

In the case where the opening / closing door opens and closes the plurality of toner discharge holes at the same time, the toner discharge holes can be opened and closed at the same time, so that a user-friendly toner conveying device can be obtained.

In the case where the opening / closing door opens and closes the plurality of toner discharge holes independently of each other, even if the toner discharged from the plurality of toner discharge holes accumulates for some reason, the open / close door is biased. By closing only the toner discharge holes corresponding to the toner that has accumulated a lot, it is possible to eliminate the bias of the toner and to transport the toner substantially uniformly.

Further, the toner conveying path has the shaft portion and the blade surface, and the toner conveying screw for conveying the toner by rotating the shaft portion, and the toner conveying screw is housed therein. In the case where the toner conveying path is formed by a conveying groove through which the toner passes, a toner conveying path is constituted by the toner conveying screw and the conveying groove, so that a toner conveying path having a relatively simple structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a first embodiment of a toner conveying device.

FIG. 2 is a schematic diagram illustrating a state in which a toner opening / closing hole is opened / closed.

FIG. 3 is a perspective view illustrating a state in which the toner conveying device illustrated in FIG. 1 is removed from a developing device.

FIG. 4 is a perspective view showing an example in which the toner conveying device shown in FIG. 1 is incorporated in a developing device.

FIG. 5 is a perspective view illustrating a second embodiment of the toner conveying device.

FIG. 6 is a perspective view showing an example in which the toner conveying device shown in FIG. 5 is incorporated in a developing device.

7 is a perspective view illustrating an example in which the toner conveying device illustrated in FIG. 5 is used as a toner discharging device that conveys waste toner from a cleaning device to a waste toner box.

FIG. 8 is a schematic diagram illustrating an example of a conventional image forming apparatus.

FIG. 9 is a perspective view illustrating a schematic configuration when a toner conveying device is used as a toner supply device that supplies toner from a hopper to a developing device.

FIG. 10 is a perspective view showing the toner supply device removed from the developing device.

FIG. 11 is a side view schematically illustrating a schematic configuration of a toner supply device.

FIG. 12 is a side view schematically illustrating a conveyance groove in which toner is accumulated.

FIG. 13 illustrates a waste toner transport device that transports toner scraped off by a cleaning blade to a waste toner box.

FIG. 14 is a schematic diagram illustrating waste toner stored in a waste toner box.

[Explanation of symbols]

10 Image Forming Apparatus 80, 120 Toner Conveying Apparatus 90, 130 Conveying Groove 90a, 90b, 90c, 130a, 130b, 130
c Toner discharge holes 92, 122a, 122b, 122c Open / close doors 98, 138 Toner supply ports 100, 140 Conveyor screws 100a, 140a Shafts 100b, 140b Blade surfaces

Claims (4)

[Claims] 1. An image forming apparatus for supplying a toner to an electrostatic latent image formed on an image carrier to obtain a toner image, the toner conveying the toner from a predetermined first location to a predetermined second location. In the transport device, one toner transport path in which the first location and the second location are formed and toner is transported, and a toner supply port formed in the first location and supplied with toner And a plurality of toner discharge holes formed at the second location for discharging toner, and an opening / closing door for opening and closing the plurality of toner discharge holes. 2. The toner conveying device according to claim 1, wherein the opening and closing door opens and closes the plurality of toner discharge holes simultaneously. 3. The toner conveying device according to claim 1, wherein the opening and closing door opens and closes the plurality of toner discharge holes independently of each other. 4. The toner conveying path has a shaft extending in a direction in which the conveying path extends and a blade surface spirally formed on an outer peripheral surface of the shaft, and by rotating the shaft, 2. A toner conveying screw for conveying toner, and a conveying groove in which the toner conveying screw is accommodated and through which the toner passes.
4. The toner conveying device according to 2 or 3.