JP2006030526A - Toner transporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner transporting device which allows the transporting precision and reliability to be improved by stably transporting toner without loss in a delivery part neither occurrence of toner stagnancy. <P>SOLUTION: In a toner transporting device 100, a first toner transporting path 111 in an upstream side, a second toner transporting path 121 placed below it, and first and second toner transporting screws 112 and 122 are provided, and toner 102 transported in the first toner transporting path 111 by the first toner transporting screw 112 is delivered from a delivery part 103 to the second toner transporting path 121, and the delivered toner 102 is transported along the second toner transporting path 121 by the second toner transporting screw 122, and a brush (toner discharging means) 111 is provided near the delivery part 103 on a screw shaft 112a of the first toner transporting screw 112. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toner conveying apparatus for conveying toner in an image forming apparatus that forms an image by electrophotography using toner.

  In an image forming apparatus employing an electrophotographic system, waste toner that is discharged without being transferred from a photoreceptor to a recording material or a transfer belt is generated. This waste toner is collected in a collection container installed inside the image forming apparatus. There is a need.

  By the way, since the toner used in the electrophotographic image forming apparatus has sufficient fluidity in a state before use, it is rare that the toner forms a coagulation flaw. Also, since the fluidity is stable, there is almost no difference in fluidity due to environmental differences and toner lot differences.

  However, the waste toner once passed through the image forming process has different properties from that of the toner before use due to decomposition of the filler and mixing of paper dust, and the fluidity is greatly reduced. The transportability is also greatly reduced. In addition, agglomerated soot is easily formed, and if the agglomerated toner continues to stay in the conveyance path, the toner conveyance means may be locked or damaged due to toner clogging, and further, the toner may be discharged onto the photoreceptor due to defective toner discharge inside the developing device. Toner adhesion may occur and image defects may occur.

  On the other hand, in order to reduce the size of the image forming apparatus, there is a case in which means for returning waste toner to the inside of a hopper that has been filled with toner without using a collection container is employed. In this case, only a cartridge system in which the developing device is replaced when the toner becomes empty can be employed (see Patent Document 1). In this system, the conveyance path for returning the waste toner faces upward, which is difficult as a conveyance means. However, a configuration is adopted in which the conveyance is performed upward using a flexible screw without a shaft only in the spiral portion. An example is shown in FIG.

  FIG. 6 is a perspective view of a process cartridge 22 having a conventional toner conveying device. In the illustrated process cartridge 22, the process cartridge 22 is discharged from a photosensitive member (not shown) provided upstream of the image forming process in the main body of the image forming apparatus. The waste toner is dropped by gravity, the waste toner is received from the upper part of the entrance opening 19 of the transport pipe, and the waste toner is guided into the flexible tube 21 having the flexible screw 20 built therein.

  Here, the flexible screw 20 is directed to the upper part of the process cartridge 22, and conveys the waste toner to the upper part of the process cartridge 22 and collects it in a bag 24 disposed inside the hopper 23. Although not shown, the flexible screw 20 is coupled to a drive shaft 25 that is rotationally driven by a drive source such as a motor at an end, and is rotationally driven by the drive shaft 25. In addition, the edge part of the part inserted in the inside of the tube 21 of the flexible screw 20 is a free end.

  By the way, the conventional waste toner conveying device accommodates the waste toner directly in the waste toner container from the developing device, and conveys the waste toner from the transfer belt and the waste toner from the developing device through separate conveyance paths, respectively. Some waste toner containers are collected. In addition, the direction of waste toner conveyance is set to be horizontal or downward in order to minimize the possibility of a conveyance failure due to stagnation or the like, and the connecting portion of the conveyance path also uses the gravity to dispose the waste toner downward. The composition to drop is mainstream.

  Further, in the conveyance of waste toner, there is a possibility that the toner adheres to the wall surface of the pipe line due to the influence of charging or the like even in the transfer section using the gravity, and the toner clogging with the attached toner as the head may occur. For such toner clogging due to charging, there is also a toner clogging prevention device provided at a connecting portion between units of a toner recovery path (see, for example, Patent Document 2).

  In the example shown in FIG. 6, the waste toner generated in each process cartridge 22 is only collected, and it is sufficient that the waste toner can be collected until the life of the process cartridge 22, that is, until the toner in the hopper 23 becomes empty. For this reason, the amount of toner transported by the transport unit is small, and it is only necessary to ensure the performance of the process cartridge 22 only, so that the configuration with the flexible screw 20 is realized.

Japanese Patent Laid-Open No. 9-281866 Japanese Patent Laid-Open No. 11-084968

  However, in the method shown in FIG. 6, since the entire process cartridge 22 is replaced and used when the toner becomes empty, the process cartridge 22 is replaced as compared with the toner replenishing method that replenishes and uses only the toner. There is a problem that the cycle is shortened and the running cost is increased. Therefore, in order to reduce the running cost, it is necessary to adopt a toner replenishing method.

  However, in the toner replenishment method, it is necessary to collect all waste toners together. Particularly, in a full-color machine, since four developing devices are installed, the amount of waste toner becomes large and the collection container has a large capacity. is necessary. Also, it is necessary to increase the amount of waste toner transported by the transport means for collecting waste toner, and a transport amount that is four times as much as that of the developing device is required as compared with the cartridge system.

  Also, in the image forming apparatus using the transfer belt, if the waste toner generated in each unit of the developing device and the transfer belt is collected by one waste toner container, the space of the waste toner container can be reduced, and image formation is performed. The entire apparatus can be miniaturized. In the case of toner conveyance that always uses gravity, the degree of freedom in the arrangement of the conveyance path is small, and the arrangement of the toner replenishing container and the waste toner container is naturally determined. If the upward conveyance is realized, the degree of freedom of arrangement of the replenishment toner container and the waste toner container is increased.

  However, since the powder is conveyed, the flow rate is difficult to be constant, and depending on the type and state of the toner, the toner is liable to stay at a bent portion in the middle. In particular, waste toner may contain paper dust, so that the fluidity of the toner is poor, and toner stays and aggregates easily.

  Further, in the upper conveyance path for conveying the toner against the gravity by the screw, the downstream toner that is dropped by the gravity is configured to be conveyed by the conveyance force of the toner conveyed from the upstream. The toner is filled in the upper conveyance path. For this reason, the loss of the toner conveyance amount becomes large at the transfer portion to the upper conveyance path, causing toner congestion and toner clogging at the upstream portion of the toner conveyance path.

  Also, in the method of dropping toner by the vibration of the flexible film as in Patent Document 2, if the toner jam occurs on the downstream side of the connecting portion as in the case of upward conveyance, the conveyance force is insufficient. A toner jam occurs on the upstream side of the connecting portion.

  The present invention has been made in view of the above problems, and the object of the present invention is to prevent toner congestion without loss at the transfer section even in toner conveyance that easily aggregates or toner conveyance with upward conveyance. It is an object of the present invention to provide a toner transport device that can stably transport toner without generating toner and can improve transport accuracy and reliability.

  In order to achieve the above object, the present invention can rotate at least in the first toner transport path on the upstream side, the second toner transport path located on the downstream side thereof, and the first and second transport paths, respectively. A first toner conveying screw and a second toner conveying screw arranged, and the toner conveyed through the first toner conveying path by the first toner conveying screw is delivered from the delivering unit to the second toner conveying path, In the toner transport device for transporting the transferred toner along the second toner transport path by the second toner transport screw, a toner discharge means is provided in the vicinity of the transfer portion of the screw shaft of the first toner transport screw. Is provided.

  The present invention also includes at least a toner transport path and a toner transport screw rotatably disposed therein, and a toner recovery container connected to a toner discharge port that opens in the toner transport path. In the toner transport device for discharging the toner transported through the toner transport path from the toner discharge port to the toner recovery container and collecting the toner, a toner discharge unit is provided in the vicinity of the toner discharge port of the screw shaft of the toner transport screw. It is characterized by that.

  Here, the toner discharge means is composed of a flexible film, an elastic member such as rubber, or a brush.

  Further, the length of the toner discharge means in the screw radial direction is set longer than the radius of the screw blades of the toner conveying screw.

  Further, the toner discharge means is rotationally driven integrally with the toner conveying screw.

  According to the toner transport device of the present invention, the toner discharge means rotates integrally with the screw shaft and discharges the toner from the delivery section to the second toner transport path, or from the toner discharge port to the toner collection container. In order to perform the discharging function, the toner conveyed through the toner conveyance path is reliably discharged to the second toner conveyance path or the toner collection container without staying. As a result, the toner can be stably transported without loss at the transfer section or the toner discharge port and without causing toner congestion even in the transport of toner that easily aggregates and the transport of the toner upward. The conveyance accuracy and reliability can be improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Since the image forming method by the developing device and the toner replenishment and recovery method are well known, description thereof will be omitted, and the configuration of the transfer unit of the toner conveyance path and the toner conveyance method, which are the gist of the present invention, are described below. Only that will be described.

<Embodiment 1>
1 is a perspective view of a toner conveying device according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view of the delivery unit of the toner conveying device as seen from the upstream conveyance direction, and FIG. 3 is a delivery unit of the toner conveying device. It is sectional drawing which looked at from the downstream conveyance direction.

  In the illustrated toner conveyance device 100, reference numeral 111 denotes a first toner conveyance path, 121 denotes a second toner conveyance path, and both the toner conveyance paths 111 and 121 intersect at a predetermined angle. As shown in FIGS. 2 and 3, the end of the path 111 opens into the end of the second toner transport path 121 via the transfer unit 103.

  Here, the first toner transport path 111 is an upstream transport path that passes the toner 102 to the second toner transport path 121 that is the upper transport path, and is included in the first toner transport path 111. A first toner conveying screw 112 is rotatably arranged. The first toner conveying screw 112 is configured by attaching a spiral first screw blade 112b to a first screw shaft 112a, and is driven to rotate in the direction indicated by an arrow a by a driving means (not shown). .

  The second toner transport path 121 is a transport path that is located on the downstream side of the first toner transport path 111 and transports the toner 102 upward, and includes a second toner transport screw therein. 122 is rotatably arranged. The second toner conveying screw 122 is configured by attaching a spiral second screw blade 122b to a second screw shaft 122a, and is driven to rotate in the direction of arrow b in FIG. 3 by a driving means (not shown). Is done.

  Thus, in the toner conveying apparatus 100 according to the present embodiment, when the first and second toner conveying screws 112 and 122 are driven to rotate, the toner 102 is transferred to the first toner conveying screw 112 by the first toner conveying screw 112. 2 is conveyed in the direction of the arrow c in FIG. 2 and falls into the second toner conveyance path 121 due to gravity (self-weight) at the transfer unit 103 and is received by the second toner conveyance path 121. Passed. The toner 102 delivered to the second toner conveyance path 121 is conveyed against the gravity in the second toner conveyance path 121 in the direction of the arrow d in FIGS. 2 and 3 by the second toner conveyance screw 122. Is done.

  In this way, if the transport direction of the toner 102 is different between the first toner transport path 111 and the second toner transport path 121, the toner 102 is likely to be congested. Further, when the second toner transport path 121 transports upward as in the present embodiment, the toner 102 is congested due to the transport force that moves upward in the second toner transport path 121 and the gravity that tends to return downward. Occurs, and the second toner transport path 121 is filled with the toner 102. For this reason, the toner 102 is likely to stay in the vicinity of the transfer unit 103 of the first toner conveyance path 111. Further, when the toner 102 to be transported is waste toner, the possibility of aggregation of the toner 102 in the vicinity of the transfer unit 103 is further increased.

  Therefore, in this embodiment, in order to reliably transfer the toner 102 staying in the vicinity of the transfer unit 103 to the second toner transfer path 121, the transfer unit of the first screw shaft 112a of the first toner transfer screw 112 is used. A brush 101 serving as a toner discharge unit is provided in the vicinity of 103. Here, the screw radial direction length (hair height) of the brush 101 is set to be longer than the height (radius) of the first screw blade 112b.

  Thus, the brush 101 has a function of rotating in the same direction (in the direction of arrow a in FIG. 2) integrally with the first screw shaft 112a and discharging the toner 102 from the transfer unit 103 to the second toner transport path 121. Therefore, the toner 102 transported to the delivery unit 103 of the first toner transport path 111 is reliably discharged to the second toner transport path 121 without staying. As a result, the toner 102 can be stably transported without loss at the transfer unit 103 and without causing the toner 102 to be jammed even when transporting the toner 102 that easily aggregates or transporting the toner 102 upward. It is possible to improve the conveyance accuracy and reliability.

  The first screw blade 112b is provided with a returning screw blade 112ca as shown in FIG. 3 in order to prevent the toner 102 from being jammed or aggregated at the end of the first toner transport path 111. Also good. In this case, the brush 101 is disposed between the first screw blade 112b and the returning screw blade 112ca, and the toner 102 is always conveyed to a place where the brush 101 is disposed (near the delivery unit 103). The brush 101 is disposed on the first screw shaft 112a side, and the toner 102 conveyed to the vicinity of the transfer unit 103 is downstream (second) with respect to the transfer unit 103 as the first screw shaft 112a rotates. The toner is forcibly discharged regardless of the toner filling state in the toner transport path 121).

  In the present embodiment, the brush 101 is used as the toner discharge means, but instead, a flexible film, an elastic member such as rubber, or the like may be used.

<Embodiment 2>
Next, an embodiment of the present invention will be described with reference to FIGS.

  4 is a cross-sectional view of the toner discharge port portion of the toner transfer device according to the present embodiment as viewed from the transfer direction, and FIG. 5 is a cross-sectional view of the toner discharge port portion of the toner transfer device as viewed from the screw rotation direction. In these drawings, the same elements as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted below.

  In the toner transport apparatus 100 according to the present embodiment, a toner discharge port 103 is opened in the toner transport path 111, and a toner recovery container 104 is connected to the toner discharge port 103.

  Thus, in the toner conveying apparatus 100 according to the present embodiment, when the toner conveying screw 112 is rotationally driven in the direction of the arrow a in FIG. 5, the toner 102 is moved in the toner conveying path 111 by the toner conveying screw 112 as shown in FIG. , And is dropped and collected from the toner discharge port 103 into the toner collection container 104 by gravity (self-weight).

  Here, also in the present embodiment, a brush 101 serving as a toner discharge unit is provided in the vicinity of the toner discharge port 103 of the screw shaft 112a of the toner conveying screw 112.

  The brush 101 rotates in the same direction as the screw shaft 112a (in the direction of the arrow a in the figure) and discharges the toner 102 from the toner discharge port 103 to the toner collection container 104. Even if temporary congestion or cross-linking of the toner 102 occurs at the toner discharge port 103 due to an increase in the flow rate or the like, the toner 102 can be reliably discharged, and as in the first embodiment, the conveyance accuracy and reliability are improved. Can be achieved.

  The present invention is useful for toner conveyance in an image forming apparatus that forms an image using toner by electrophotography.

1 is a perspective view of a toner conveying device according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of a delivery unit of the toner conveyance device according to Embodiment 1 of the present invention as viewed from the upstream conveyance direction. FIG. 4 is a cross-sectional view of a delivery unit of the toner conveyance device according to the first exemplary embodiment of the present invention as viewed from a downstream conveyance direction. FIG. 6 is a cross-sectional view of a toner discharge port portion of a toner transport device according to a third embodiment of the present invention as viewed from the transport direction. FIG. 6 is a cross-sectional view of a toner discharge port portion of a toner conveyance device according to a third embodiment of the present invention as viewed from the screw rotation direction. It is a diagram of a conventional toner conveying device.

Explanation of symbols

100 Toner Conveying Device 101 Brush (Toner Discharge Unit)
102 Toner 103 Delivery section (toner discharge port)
104 Toner collection container 111 First toner transport path 112 First toner transport screw 112a First screw shaft 112b First screw blade 112c Return screw blade 121 Second toner transport path 122 Second toner transport screw 122a Second screw shaft 122b Second screw blade

Claims (11)

At least a first toner transport path on the upstream side, a second toner transport path positioned on the downstream side thereof, and first and second toner transports rotatably disposed in the first and second transport paths, respectively. A screw, which is transferred to the second toner transfer path from the transfer section by the first toner transfer screw, and is transferred to the second toner transfer path. In a toner conveying device that conveys along the second toner conveying path by a conveying screw,
A toner conveying device, wherein a toner discharge means is provided in the vicinity of the delivery portion of the screw shaft of the first toner conveying screw.   2. The toner conveying device according to claim 1, wherein the toner discharge means is constituted by an elastic member.   3. The toner conveying device according to claim 1, wherein the toner discharging means is constituted by a brush.   The toner conveying device according to claim 1, wherein a length of the toner discharging unit in a screw radial direction is set longer than a radius of a screw blade of the first toner conveying screw. At least a toner conveying path, a toner conveying screw rotatably disposed in the toner conveying path, and a toner recovery container connected to a toner discharge port that opens in the toner conveying path, and the toner conveying screw conveys the toner conveying path. In a toner transport device for discharging the toner to be discharged from the toner discharge port to the toner recovery container and recovering the toner,
A toner conveying device comprising toner discharge means provided in the vicinity of the toner discharge port of the screw shaft of the toner conveying screw.   6. The toner conveying device according to claim 5, wherein the toner discharge means is constituted by an elastic member.   7. The toner conveying device according to claim 5, wherein the toner discharging means is constituted by a brush.   The toner conveying device according to claim 5, wherein a length of the toner discharging unit in the radial direction of the screw is set longer than a radius of a screw blade of the toner conveying screw.   The toner transport device according to claim 1, wherein the toner transport path is a waste toner transport path.   The toner conveying device according to claim 1, wherein the toner discharging unit is rotationally driven integrally with the toner conveying screw.   At the end of the toner conveying screw, a return screw blade having a spiral winding direction opposite to the conveying direction is provided, and the toner discharge means is disposed between the screw blade wound in the conveying direction and the returning screw blade. The toner conveying device according to claim 1, wherein the toner conveying device is disposed in the toner conveying device.

Images