JP2000131947A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of preventing the blocking phenomenon of developer from occurring at an end on a device side, and preventing a carrying member of developer or a drive transmission gear from being damaged due to that the carrying member is locked. SOLUTION: This device having a 1st carrying member 11 carrying toner in the longitudinal direction of a case 1 from a toner storing part 10 and a 2nd carrying member 12 carrying the toner in a reverse direction to the carrying direction of the member 11 in the case 1 is provided with a reverse carrying part 13 for carrying the toner carried by the member 11 in the reverse direction to the carrying direction of the member 11 at the final end in the carrying direction of the member 11. Thus, the toner carried by the member 11 reaches the carrying area of the member 12 and is prevented from being packed near the final end in the carrying direction of the member 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
A case having an opening for the latent image carrier, a developer carrier provided in the case, and arranged so as to be partially exposed from the opening, and supplying a developer to the developer carrier; Supply member, and a developer accommodating section for accommodating the developer,
A first transport member that transports the developer in the longitudinal direction of the supply member, and a developer that is located above the first transport member and that is opposite to the transport direction of the first transport member. The present invention relates to a developing device having a second conveying member for conveying.

[0002]

2. Description of the Related Art Conventionally, a developing device which has been widely put into practical use includes a developing roller, a toner hopper for storing toner to be supplied to the developing roller, and an agitator for sending toner in the toner hopper to the developing roller. There is a horizontal type arranged in the direction. However, in such a horizontal developing device, the cross section of the developing device is larger than the ratio occupied by the photoreceptor cross section, and the degree of freedom in layout in the main body of the apparatus is reduced, which causes an increase in size of the apparatus. I was

In order to solve the above-mentioned problem, a conveying member for conveying the toner in parallel with the developing roller and the supply roller is provided, and a developing device for conveying the toner in a longitudinal direction from a toner container provided at an end of the apparatus. (See Japanese Patent Application Laid-Open No. 5-313488). Thereby, the necessary toner can be supplied to the developing roller and the supply roller, and even when configuring an image forming apparatus such as a color copying machine or a color printer, which requires three to four developing devices,
The degree of freedom in layout within the device body can be increased,
The entire device can be reduced in size.

Further, in the developing device disclosed in the above-mentioned publication, in addition to the first conveying member for conveying the toner from the toner storage section to the developing section, the developing apparatus is arranged in a direction opposite to the conveying direction of the first conveying member. A developing device provided with a second transport member for transporting toner has also been proposed. As a result, the bias of the toner in the longitudinal direction in the developing device can be prevented.

[0005]

However, the above-mentioned 2
Also in the developing device having the two conveying members, the toner conveyed from the toner container by the rotation of the first conveying member has such a force that the toner is always pressed against the case side opposite to the toner container in the longitudinal direction. work. As a result, the toner is packed in the vicinity of the final end of the first conveying member in the conveying direction, the rotational torque of the first conveying member increases, and in some cases, a complete developer blocking phenomenon occurs, and the conveying member locks. There is a possibility that the transfer member, the drive transmission gear or the like may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to transfer the developer conveyed by the first conveying member to the final end of the first conveying member in the conveying direction. By providing a displacing means for displacing the first conveying member from the first conveying member to the starting end of the second conveying member in the conveying direction, the first conveying member is locked and the first conveying member or the drive transmission is prevented. It is an object of the present invention to provide a developing device which can prevent the gears and the like from being damaged.

[0007]

According to another aspect of the present invention, there is provided a developing device, comprising: a case having an opening to a latent image carrier; A developer carrying member arranged so that the portion is exposed,
A supply member for supplying the developer to the developer carrier, a developer accommodating portion for accommodating the developer, a first conveyance member for conveying the developer in a longitudinal direction of the supply member, and the first conveyance And a second transporting member that transports the developer in a direction opposite to the transporting direction of the first transporting member and that is transported by the first transporting member. Displacement means for displacing the developer from a final end in the transport direction of the first transport member to a start end in the transport direction of the second transport member is provided.

In the developing device according to the first aspect, the displacing means causes the developer conveyed by the first conveying member to start in the conveying direction of the second conveying agent from the final end in the conveying direction of the first conveying member. Displace to the end. Therefore, the developer transported by the first transport member reaches the transport area of the second transport member without remaining at the final end in the transport direction of the first transport member, and is transported again to the developing unit for use. Thus, packing is less likely to occur in the vicinity of the final end of the first transport member in the transport direction.

The developing device according to a second aspect of the present invention is the developing device according to the first aspect, wherein the developer conveyed by the first conveying member to the final end in the conveying direction of the first conveying member as the displacement means. And a reverse transport unit that transports the first transport member in a direction opposite to the transport direction of the first transport member.

According to the third aspect of the invention, the developer is transported in the reverse direction by the reverse transport section provided at the last end of the first transport member in the developer transport direction. For this reason, the developer transported by the first transport member is pushed up by a bulging action occurring near the reverse transport section, reaches the transport area of the second transport member, is transported again to the developing section, and is used. In addition, unlike the conventional case of receiving the protruding action by hitting the side surface of the case, when the pressure is excessively increased, the developer is moved upstream in the reverse conveying direction in the reverse conveying section. Can escape, so the first
Packing in the vicinity of the final end of the conveying member in the conveying direction is unlikely to occur.

According to a third aspect of the present invention, in the developing device according to the first aspect, the bottom of the case serves as the displacement means, and the second transporting means moves from a final end of the first transporting member in a transporting direction. A slope is formed over the starting end of the member in the transport direction.

According to a fourth aspect of the present invention, in the developing device according to the third aspect, the last end of the first conveying member in the conveying direction is moved to the second conveying member in the conveying direction of the first conveying member. Is set on the upstream side of the start end in the conveying direction.

In the developing device according to the third and fourth aspects, the slope provided at the bottom of the case from the final end in the conveying direction of the first conveying member to the starting end of the second conveying member in the conveying direction, Push up the developer. Therefore, the developer transported by the first transport member is forcibly pushed up along the slope, reaches the transport area of the second transport member, is transported again to the developing unit, and is used. Further, since the developer is pushed up by the slope provided in advance in this way, packing is not easily generated in the vicinity of the end of the first conveying member in the conveying direction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device provided in an image forming apparatus such as a copying machine will be described below. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the developing device according to the present embodiment. FIG. 2 is a perspective view of the appearance of the developing device according to the present embodiment.

As shown in FIG. 1, the developing device 30 is disposed below the photosensitive member 20 serving as an electrostatic latent image carrier, and applies an electrostatic latent image formed on the photosensitive member 20 rotating in the direction of arrow A to the developing device. A non-magnetic one-component developer (hereinafter, referred to as toner) is supplied. As shown in FIG. 2, the developing device 30 includes a case 1, a toner container 10 connected to one end of the case 1 in the longitudinal direction, and a toner cartridge 15 detachably connected to the upper portion of the toner container 10. It is composed of

In FIG. 1, an opening 1a is formed in the case 1 at a portion facing the photoreceptor 20 which rotates in the direction of arrow A. In the case 1, there is provided a developing roller 2 as a developer carrying member arranged so that a part thereof is exposed from the opening 1a. This developing roller 2
Is arranged so as to rotate in the direction of arrow B in the opening 1a in the same direction as the moving direction of the photoconductor 20 at a predetermined peripheral speed ratio with respect to the photoconductor 20.

A supply roller 3 as a developer supply member made of an elastic material such as foamed polyurethane is provided below the development roller 2 so as to rub the surface of the supply roller 3 with the development roller 2. The supply roller 3 is configured to rotate in a direction indicated by an arrow C in the same direction as the developing roller 2 at a rubbing portion a with the developing roller 2 at a predetermined peripheral speed ratio with respect to the developing roller 2. The rubbing portion a is a position where the supply roller 3 supplies toner to the developing roller 2. The opening 1a is located downstream of the rubbing portion a of the developing roller 2 in the movement direction.
Is provided with a blade 4 made of an elastic body such as a metal plate having a spring property or urethane rubber so that its free end contacts the developing roller 2.

Further, in the case 1, a first toner conveying member 11 located on the upstream side in the moving direction from the rubbing portion a of the supply roller 3, and a first toner conveying member 11 located above the first toner conveying member 11 are provided. And two toner conveying members 12.
The first toner conveying member 11 and the second toner conveying member 12 are formed in a screw shape as shown in FIGS. 3 and 4 described later, and a developing roller is provided from the toner container 10 to the other side plate of the case 1. 2, and is arranged in parallel with the supply roller 3, and conveys the toner in the longitudinal direction of the case 1. Specifically, the first toner conveying member 11 is not shown in the direction of arrow D in FIG. 1, and the second toner conveying member 12 is not shown in the direction of arrow E opposite to the first toner conveying member 11. The drive mechanism is configured to rotate in conjunction with a predetermined peripheral speed ratio. Here, in the case 1, the supply roller 3 is disposed so as to also be in contact with the case 1, and a rib 1 b is formed, so that a toner conveying space surrounding the first toner conveying member 11 is formed. As a result, the first toner conveying member 11 conveys the toner from the toner container 10 to the other side surface 6 of the case 1 (from left to right in FIG. 2), and the rubbing portion a in the rotation direction C of the supply roller 3. Is supplied upstream of the toner. Second toner transport member 12
Transports the toner in the opposite direction to the first toner transport member 11, that is, from the other side surface 6 of the case 1 to the toner storage unit 10.

The operation of the developing device 30 configured as described above will be described. As shown in FIG. 1, the developing roller 2 and the supply roller 3 are rotated in a direction indicated by arrows B and C at a predetermined peripheral speed ratio. Then, the toner cartridge 15
The toner supplied from the toner supply unit 10 to the toner storage unit 10 is transported by the first toner transporting member 11 from the near side to the far side of the drawing, and is supplied over the entire area of the supply roller 3 in the axial direction.
The toner supplied to the supply roller 3 is supplied while being charged to the surface of the developing roller 2 in the rubbing portion a, and is carried on the surface of the developing roller 2. The toner carried on the surface of the developing roller 2 is formed into a uniform and thin toner layer having a predetermined thickness by the blade 4, and the electrostatic latent image formed on the surface of the photoconductor 20 is developed by contact or non-contact development.

Here, the amount of toner in the toner conveying space surrounding the toner conveying member 11 must be equal to or larger than the maximum amount consumed in the developing process. However, an image developed by a copying machine or the like does not consume a constant amount of toner due to its entire area and image arrangement in the width direction. The toner in the transport space is always transported to the side surface 6 of the case 1 on the opposite side of the toner storage unit 10 by the rotation of the first toner transport member 11 and is accumulated. Further, depending on the image size (sheet passing size), image layout, image area, etc., the developing device 30
Since there is a difference in the toner consumption amount in the width direction, a deviation occurs in the toner amount in the conveyance space width direction.

Therefore, as shown in FIG. 1 (a), when the toner amount of each part in the toner conveying space is equal to or less than the second toner conveying member 12, the toner is transferred to the case 1 by the first toner conveying member 11. From the near side to the far side (from left to right in FIG. 2). However, as shown in FIG. 1B, when the amount of toner in each part in the toner conveying space reaches the conveying area of the second toner conveying member 12, that is, the amount of surplus toner, the surplus toner becomes the second amount. Toner conveying member 12
As a result, the toner is conveyed from the back side to the front side (from right to left in FIG. 2) of the case 1, and at the same time, the toner is supplemented to the portion where the toner amount is small, and the surplus toner is returned to the above-described toner storage unit 10. As a result, it is possible to maintain a constant amount of toner in the toner transport space and a substantially uniform amount of toner in the width direction without requiring complicated control.

By the way, the toner conveyed to the back of the case 1 by the rotation of the first toner conveying member 11 is always pressed against the side face 6 of the case 1 opposite to the longitudinal direction of the case 1. The toner is packed in the vicinity of the final end of the first toner conveying member 11 in the conveying direction. Therefore, the rotational torque of the first toner conveying member 11 increases, and in some cases, a complete toner blocking phenomenon occurs, the first toner conveying member 11 locks, and the first toner conveying member 11 or the drive transmission The gear may be damaged.

Therefore, in the developing device 30 of the present invention, as shown in FIG. 3, the toner conveyed by the first toner conveying member 11 is conveyed to the final end of the first toner conveying member 11 in the conveying direction. A reverse transport portion 13 is formed in a screw shape having a reverse pitch of one pitch so as to transport in a direction opposite to the transport direction of the first toner transport member 11.
As a result, in the vicinity of the final end of the first toner conveying member 11 in the conveying direction, the toner conveyed by the first toner conveying member 11 and the toner returned in the reverse direction by the reverse conveying portion 13 collide with each other. The toner conveyed by the first conveying member 11 is pushed up in the direction of arrow F in the drawing by a bulging action. Therefore, the toner is not pressed against the side surface 6 of the case 1, reaches the transport area of the second toner transport member 12, and is not packed at the final end of the first toner transport member 11 in the transport direction. .

Further, a developing device according to another embodiment will be described. For example, as shown in FIG. 4, the shape of the bottom of the case 1 near the final end in the transport direction of the first toner transport member 11 may be formed as an inclined surface as the displacement means. In FIG. 4, parts and members having the same functions as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the last end of the first toner conveying member 11 in the conveying direction is connected to the first toner conveying member 1.
In the first transport direction, the second toner transport member 12
Is set upstream from the start end in the conveyance direction of
A slope 7 is formed at the bottom from the end of the first toner conveying member 11 in the conveying direction to the start end of the second conveying member 12 in the conveying direction. As a result, the toner transported by the first toner transport member 11 to the final end in the transport direction is pushed up along the slope 7 in the direction of arrow G in the figure, and reaches the transport area of the second toner transport member 12. As described above, packing is not performed at the final end in the transport direction of the first transport member.

Here, in the above embodiment, a tapered slope is provided at the bottom of the case 1 as shown in FIG. 4, but the present invention is not limited to this, and it is a matter of course that a curved slope may be used. It is.

As described above, according to each embodiment, the toner conveyed by the first conveying member is supplied to the reverse conveying section 13 or the slope 7.
As a result, the toner does not reach the transport area of the second transport member and is not packed at the final end in the transport direction of the first transport member, so that the toner blocking phenomenon is prevented and the first toner transport member 11 is locked. Thus, it is possible to prevent the first toner conveying member 11 or the drive transmission gear or the like from being damaged.

In this embodiment, the toner container 10
Although a detachable toner supply member, a so-called toner cartridge 15, is used, the present invention is not limited to this. For example, as shown in FIG. 5, a predetermined number of replacement toners of the developing device 30 may be stored in the toner storage portion 10, and the developing device 30 may be replaced when the toner is insufficient. In this embodiment, an example in which a non-magnetic one-component toner is used as a developer has been described. However, the present invention can be applied to a developing device using a magnetic one-component toner or a two-component toner.

[0029]

According to the first aspect of the present invention, the developer conveyed by the first conveying member is moved from the final end in the conveying direction of the first conveying member to the start end of the second conveying member by the displacement means. The developer is conveyed to the developing unit again, and the developer is effectively used. Therefore, the developer blocking phenomenon can be prevented, and the first conveying member or the drive transmission gear can be prevented from being damaged. .

According to the second aspect of the present invention, the developer conveyed by the first conveying member is pushed up by the bulging action of the reverse conveying portion provided at the last end of the first conveying member in the developer conveying direction. To reach the transport area of the second transport member, and is transported again to the developing section, so that the developer is effectively used. Therefore, the developer blocking phenomenon is prevented, the first transport member is locked, and the first transport member is locked. It is possible to prevent the transport member or the drive transmission gear from being damaged.

According to the third and fourth aspects of the present invention, the developer transported by the first transport member is moved from the final end of the first transport member in the transport direction to the transport direction of the second transport member. Forcibly pushed up by a slope provided at the bottom of the case toward the start end, the conveyance reaches the conveyance area of the second conveyance member, and is conveyed again to the developing section, so that the developer is effectively used. This prevents the phenomenon and prevents the first transporting member from being locked and the first transporting member or the drive transmission gear from being damaged.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view illustrating a case where the amount of toner inside a toner conveying space in a developing device according to an embodiment is equal to or less than a second conveying member. FIG. 4B is a schematic cross-sectional view illustrating a case where the amount of toner inside the toner conveyance space in the developing device is equal to or larger than the conveyance area of the second conveyance member.

FIG. 2 is a schematic perspective view of the developing device.

FIG. 3 is an axial sectional view of the developing device.

FIG. 4 is an axial sectional view of a developing device according to another embodiment.

FIG. 5 is a schematic perspective view of a developing device according to another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 case 2 developing roller 3 supply roller 4 blade 6 case side surface 7 slope 10 toner container 11 first toner transport member 12 second toner transport member 13 reverse transport portion 15 toner cartridge 20 photoconductor 30 developing device

Claims (4)

[Claims] A case having an opening for a latent image carrier;
A developer carrying member provided in the case and arranged so that a part thereof is exposed from the opening, a supply member for supplying the developer to the developer carrying member, and a developer containing the developer An accommodating portion, a first transport member for transporting the developer in a longitudinal direction of the supply member, and a position located above the first transport member and opposite to the transport direction of the first transport member And a second transporting member for transporting the developer to the second transporting member. The developer transported by the first transporting member is transferred from a final end in the transporting direction of the first transporting member to the second transporting member. And a displacing means for displacing to the start end in the conveying direction. 2. The developing device according to claim 1, wherein the developer conveyed by the first conveying member is transferred to a final end of the first conveying member in the conveying direction by the first conveying member. A reverse transport section for transporting in a direction opposite to the transport direction of the developing device. 3. The developing device according to claim 1, wherein, as the displacement means, a bottom of the case extends from a final end in the conveying direction of the first conveying member to a starting end in the conveying direction of the second conveying member. A developing device having a slope. 4. The developing device according to claim 3, wherein the end of the first conveying member in the conveying direction is set to the starting end of the second conveying member in the conveying direction of the first conveying member. A developing device set upstream of the developing device.