JP6543821B2 - Transport apparatus, developing apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a conveying device, a developing device, and an image forming device, and more specifically, a conveying device for conveying a developer in a developing container of the developing device, a developing device provided with the conveying device, and the developing device The present invention relates to an image forming apparatus provided.

  2. Description of the Related Art Conventionally, there has been used a developing device in which a deteriorated carrier contained in a developer is replaced by supplying and discharging a two-component developer. The developing method in this developing device is called a trickle developing method.

  For example, Patent Document 1 discloses a developing housing that contains a two-component developer and has a development opening, and is disposed facing the development opening of the development housing and carries the two-component developer. A developer carrier and a plurality of stirring and conveying members disposed on the back side of the developer carrier among the developing housing and extending in the axial direction of the developer carrier are provided. Disclosed is a developing device provided with a developer circulating and conveying mechanism for circulating and conveying while stirring, and a trickle mechanism capable of gradually discharging an old developer out of the developer in the developing housing and replacing it with a new developer. There is.

  The trickle mechanism that constitutes this trickle development system controls the discharge amount of the developer from the trickle discharge port and the trickle discharge port opened in a part of the developing housing on the downstream side of the stirring conveyance member in the conveyance direction. And a backflow generating member capable of transporting the developer in a direction opposite to the direction of conveyance of the developer by the stirring and conveying member, and a gap region between the trickle discharge port and the outer periphery of the backflow generating member is above the backflow generating member It is set to the uneven distribution which narrowed the side locally.

JP 2005-221852 A

  In a developing device using such a trickle development system, the quality of the developer in the developing housing is uniformed by gradually discharging the old developer among the developers in the developing housing and replacing it with a new developer. By keeping the amount within a predetermined amount, it is possible to maintain the quality of printing.

  On the other hand, as image forming apparatuses, models having different printing speeds such as a medium-speed machine and a high-speed machine are provided in accordance with user needs. And, in these models with different printing speeds, the developing device is also designed and manufactured according to the required printing speeds. However, with regard to recent image processing apparatuses, there is a demand to reduce the total cost necessary for manufacturing by commonizing various parts in order to reduce the mold even for models with different printing speeds.

  For this reason, even in the developing device adopting the trickle developing method, it is desirable to commonly use the developing container, the stirring and conveying member, and the like in models having different printing speeds. However, in the high-speed machine, it is necessary to increase the rotational speed of the developing roller and also to speed up the transport speed of the developer by the stirring and transporting member as compared with the medium speed machine. The conveying speed of the developer of the stirring and conveying member greatly affects the height of the developer surface at the circulation junction in the developing container, and the higher the conveying speed, the larger the discharge amount of the developer.

  For example, while the rotation speed of the stirring and conveying part is about 350 rpm in the medium speed machine, it is about 500 rpm in the high speed machine, and when the developing device for the medium speed machine is used for the high speed machine As the internal pressure in the container increases and the rotation speed of the stirring and conveying member increases, the level of the liquid surface of the developer increases, and excessive discharge of the developer from the trickle discharge port occurs. In addition, when a developing device for a high-speed machine is used for a medium-speed machine, on the contrary, there arises a problem that the developer is not properly discharged from the trickle discharge port.

  In the trickle mechanism described in Patent Document 1, a backflow generating member is provided on the downstream side of an extension coaxial with the stirring and conveying member, and a trickle discharge port is provided on the downstream side thereof. In the trickle mechanism having such a configuration, even if there is a difference between the rotational speed of the developing roller and the conveyance speed of the stirring conveyance member, no consideration is given to the problem of discharging the developer from the trickle discharge port without excess or deficiency. Not.

  The present invention has been made in view of the above-described actual situation, and its object is to extend the amount of developer in the developing container even when the printing speed is different when adopting the trickle development system. Accordingly, it is an object of the present invention to provide a conveying device, a developing device provided with the conveying device, and an image forming apparatus provided with the developing device, which can be constantly maintained uniformly.

In order to solve the above problems, according to a first technical means of the present invention, a first conveyance path and a second conveyance path are disposed in parallel, and provided at both ends of the first conveyance path and the second conveyance path. And a first conveyance member for conveying the developer while stirring the developer in the first conveyance path, and stirring the developer in the second conveyance path. While transporting the developer in the second transport path, a second transport member transporting in a direction opposite to the first transport member, a transport path main body member accommodating the first transport member and the second transport member, and A third conveyance path connected to the second conveyance path on the upstream side of the direction, and the developer overflowing from the second conveyance path to the third conveyance path in the third conveyance path, the second conveyance member To the discharge port provided in the third conveyance path. A third transport member, and a third transport path member that accommodates the third transport member and is positioned and fixed with respect to the transport path main body member, and the communication from the first transport path to the second transport path A block member for restricting the flow of the developer from the first conveyance path to the second conveyance path is provided on the third conveyance path side of the mouth , and the block member has an attachment hole provided in the block member. By fitting the protrusion provided on the side of the conveyance path main body member of the third conveyance path member, the third conveyance path member is detachably provided to the third conveyance path member .

According to a second technical means of the present invention, in the first technical means, the first transport path and the second transport path have a substantially cylindrical shape, and the block member has a first transport path and a second transport path. The side surface of the block member on the side of the first conveyance path faces the outer periphery of the first conveyance member with a predetermined gap, and has a predetermined length in the axial direction. The side surface is characterized in that it has a shape in which a notch is formed in an upper portion on the communication port side.

A third technical means of the present invention is the first or second technical means, wherein the third transport path is formed coaxially with the second transport path and smaller in diameter than the second transport path. An annular plate-shaped step member for adjusting the inflow of the developer conveyed into the third conveyance path between the end portion of the third conveyance path and the block member. Furthermore, the step member is detachably provided to the third conveyance path member.

A fourth technical means of the present invention is the third technical means, wherein the step member is provided with a mounting hole provided in the step member on a protrusion provided on the side of the conveyance path main body member of the third conveyance path member. It is characterized in that it is detachably provided to the third conveyance path member by being fitted.

According to a fifth technical means of the present invention, in the third or fourth technical means, the block member and the step member are formed in the same system color.

A sixth technical means of the present invention is a developing device provided with any one of the first to fifth technical means and a developer carrier, wherein the developer carrier is obtained by the second transport member. And the developer is supplied to the developing device.

According to a seventh technical means of the present invention, there is provided an image forming apparatus comprising: the developing device of the sixth technical means; and an image forming section for forming an image on a recording medium with the developer supplied by the developing device. It is an apparatus.

  According to the present invention, when adopting the trickle development method, even if the printing speed is different, since the block member can be replaced, the amount of developer in the developing container can be constantly and uniformly kept over a long period of time It is possible to provide a conveying device, a developing device provided with the conveying device, and an image forming apparatus provided with the developing device, which can be maintained.

FIG. 1 is a perspective view showing a configuration example of a developing device provided with a conveyance device according to a first embodiment of the present invention. It is the side view which looked at the image development apparatus of FIG. 1A from the paper surface right side. It is AA sectional drawing in the image development apparatus of FIG. 1B. It is BB sectional drawing in the image development apparatus of FIG. 1B. It is an enlarged view of the paper surface right end part in the image development apparatus of FIG. 2A. It is an enlarged view of the paper surface right end part in the image development apparatus of FIG. 2B. It is CC sectional drawing in the image development apparatus of FIG. 3A. FIG. 5 is a cross-sectional view taken along the line DD in the developing device of FIG. 4. It is a figure showing an example of a block member. It is a figure which shows the other example of a block member. It is a figure showing an example of a level difference member. It is a figure which shows the other example of a level | step-difference member. FIG. 2 is an exploded perspective view of the right side of the developing device shown in FIG. 1A. FIG. 1 is a diagram showing an exemplary configuration of an image forming apparatus according to the present invention.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments according to a conveying device of the present invention, a developing device provided with the conveying device, and an image forming apparatus provided with the developing device will be described with reference to the drawings. In the following description, components denoted by the same reference numerals in different drawings may be omitted as they are the same.

First Embodiment
A first embodiment of the present invention will be described with reference to FIGS. 1A-5. FIG. 1A is a perspective view showing an example of the configuration of a developing device provided with a conveyance device according to a first embodiment of the present invention, and FIG. 1B is a side view of the developing device of FIG. 2A and 2B are a cross-sectional view taken along the line A-A and a cross-sectional view taken along the line B-B of the developing device shown in FIG. 1B respectively. FIGS. 3A and 3B respectively show the right end of the drawing sheet in the developing device shown in FIGS. FIG. 4 is a cross-sectional view taken along the line C-C in the developing device shown in FIG. 3A, and FIG. 5 is a cross-sectional view taken along the line D-D in the developing device shown in FIG.

  The developing device 1 illustrated in FIGS. 1A to 5 includes communication ports provided at both ends of the first conveyance path 10a and the second conveyance path 10b, in which the first conveyance path 10a and the second conveyance path 10b are disposed in parallel. (Slit) This is a device for circulating a developer (not shown) through 10aa and 10ab. As the developer, a two-component developer in which a toner and a carrier are mixed is stored. The carrier is a magnetic material such as iron powder or ferrite.

  The first transport path 10a and the second transport path 10b are partitioned by a partition wall 10d except for the communication ports 10aa and 10ab. In FIG. 2A, although the partition 10da is also illustrated in addition to the partition 10d, the partition 10da is a partition which is continued with the partition 10d and differs in a shape.

  The casing of the developing device 1 for forming the first conveyance path 10a and the second conveyance path 10b is called a development container and is denoted by reference numeral 10 in the figure. In addition, in FIG. 1A, in order to avoid confusion with the below-mentioned 1st conveyance member 11 and the 2nd conveyance member 12, some numerals, such as numerals 10a and 10b, are not attached. Details of the developing container 10 will be described later.

  The developing device 1 includes a developing roller (magnet roller) 15 in the developing container 10 as illustrated in FIG. 1A and the like. The developing roller 15 is disposed above the second conveyance member 12 in the vertical direction. The developing roller 15 functions as a developer carrier and is disposed at a position facing the photosensitive drum (not shown) in the image forming apparatus. The developing roller 15 carries the developer in the developing container 10 on the surface, and supplies the toner contained in the carried developer to the surface of the photosensitive drum. As a result, the electrostatic latent image formed on the surface of the photosensitive drum is developed (visualized).

  Although not shown in FIGS. 1A to 5, the doctor blade is fixed to the developing container 10 with a predetermined gap with respect to the surface of the developing roller 15. The doctor blade is a plate-like member extending in the direction of the shaft portion 15 b of the developing roller 15. The amount of the developer carried on the developing roller 15 is regulated to a predetermined amount by the doctor blade.

  Note that the actual developing container 10 is provided with a cover member covering the first conveying member 11 and the second conveying member 12 described later and the developing roller 15 in the upper part of the developing container 10 in the vertical direction. In 1A, a part of this cover member is omitted. Further, the developing device 1 also includes a toner concentration detection sensor, but these are also omitted in FIG. 1A and the like.

  Further, the development device 1 excluding the developing roller 15 and the doctor blade (and the toner concentration detection sensor) may be called a conveyance device for conveying the developer, and this conveyance device corresponds to the conveyance device according to the present invention. Do. That is, the developing device according to the present invention is a device including the transport device according to the present invention and the developer carrier, and the developer is supplied to the developer carrier side by the second transport member 12 described later.

  In the developing container 10, a third conveyance path 10c connected to the second conveyance path 10b is disposed on the upstream side in the conveyance direction of the developer in the second conveyance path 10b. As illustrated, the third transport path 10c is formed as an internal space of the projecting member 10e connected to the right end of the second transport path 10b. The projecting member 10 e is provided such that its axial position is projected as compared with the right end of the first conveyance path 10 a as viewed in the drawing. The protrusion 10e is provided with a discharge port 10t for discharging the developer downward. The discharge port 10t or the third conveyance path 10c including the same is also referred to as a trickle port. The outlet 10t is a trickle outlet. The protruding member 10 e corresponds to a third conveyance path member of the present invention.

  The portion of the developing container 10 in which the first transport member 11 and the second transport member 12 are accommodated corresponds to the transport path main body member of the present invention. The protruding member 10e constituting the third conveyance path member is manufactured separately from the portion of the developing container 10 in which the first conveyance member 11 and the second conveyance member 12 are accommodated, that is, the conveyance path main body member, The third transport path member is positioned and fixed relative to the transport path main body member.

  Further, a replenishment port 10 f for replenishing the developer into the developing container 10 is provided on the upper side of the developing container 10 and at a downstream portion on the second conveyance path 10 b side. The supply port 10 f may be provided on the upper side of the developing container 10 and on the upstream portion on the side of the first conveyance path 10 a. Although not shown, a toner supply pipe extending from a toner bottle is connected to the supply port 10f, and unused toner and unused carrier are supplied from here.

The developing device 1 supplies developer from the supply port 10f and then circulates the developer, and discharges the developer from the discharge port 10t.
In order to circulate and discharge such a developer, the developing device 1 is provided with a first conveyance member 11, a second conveyance member 12, and a third conveyance member 13 inside the development container 10.

  The first conveyance member 11 is configured as a conveyance screw that conveys the developer while stirring the developer in the first conveyance path 10a. This conveyance screw is an auger screw in which the blade portion 11a is formed in a spiral shape around the shaft portion 11b. The blade portion 11a can also be called a transfer blade or a screw blade. The blade portion 11a and the shaft portion 11b are integrally molded of resin, or metal is used for part or all of the shaft portion 11b.

  The first transport member 11 provided in the first transport path 10a supplies the developer replenished from the replenishment port 10f through the communication port 10aa to the second transport path 10b through the communication port 10ab. Here, at the downstream end of the first conveyance path 10a in the conveyance direction, the developer conveyed on the first conveyance path 10a collides with the developer stagnating at the downstream end or the wall (inner side wall) of the developing container 10 . Therefore, the developer stagnates at the downstream end in the transport direction of the first transport path 10a, and is pushed out from the communication port 10ab to the second transport path 10b.

  The first conveyance member 11 is provided with a wing portion 11c of reverse winding with the wing portion 11a at the downstream end (the right end in the drawing of FIG. 2A, FIG. 3A) of the developer in the conveyance direction. As shown in FIG. 3A etc., the blade portion 11c has a shorter pitch than the blade portion 11a, and the angle between the surface (one of the surface of the blade) pushing the developer and the shaft portion 11b is more orthogonal It's getting close. By providing such reversely wound blade portions 11c, the momentum of conveyance of the developer can be reduced. The pitch, angle, and axial length of the reverse-wound blade portion 11c may be determined so that the amount of the developer and the number of rotations of the conveyance member change so as to achieve the desired momentum of conveyance of the developer.

  The second conveyance member 12 is configured as a conveyance screw that conveys the developer in the second conveyance path 10 b in the opposite direction to the first conveyance member 11 while stirring the developer. This transport screw is also an auger screw in which the blade portion 12 a is formed in a spiral shape around the shaft portion 12 b as in the first transport member 11. The blade portion 12a and the shaft portion 12b are integrally molded of resin, or metal is used for part or all of the shaft portion 12b.

  The second conveyance member 12 provided in the second conveyance path 10 b supplies the developer to the developing roller 15 which is a developer carrier. Here, at the downstream end of the second conveyance path 10b in the conveyance direction of the second conveyance path 10b, the developer replenished from the replenishment port 10f, the developer stagnated at the downstream end, and the developer container 10 collide with the wall (inner side wall). Therefore, the developer is retained at the downstream end of the second conveyance path 10 b in the conveyance direction, and is pushed out from the communication port 10 aa to the first conveyance path 10 a.

  The second conveyance member 12 illustrated here is provided with a wing portion 12c of reverse winding with the wing portion 12a at the downstream end (the left end in the drawing of FIG. 2A) of the developer conveyance direction. The difference between the blade portion 12c and the blade portion 12a is the same as the difference between the blade portion 11c and the blade portion 11a. By providing such reversely wound blade portions 12c, the momentum of conveyance of the developer can be reduced. The pitch, angle, and axial length can be appropriately set such that the amount of developer and the number of rotations of the transport member can be changed to achieve the desired momentum of transport of the developer. In the present embodiment, the blade portion 11a and the blade portion 12a are formed to have a diameter of about 16 mm.

  The conveying screws constituting the first conveying member 11 and the second conveying member 12 can also be referred to as stirring / conveying screws in order to convey and agitate the developer. In the developing container 10, the first transport member 11 and the second transport member 12 are provided rotatably around the shaft portions 11b and 12b, respectively, and as shown in FIG. 1A and FIG. It is arranged to be parallel. Then, in the first conveying member 11 and the second conveying member 12, the developer circulation as described above is made possible by rotating the shaft portion 11b and the shaft portion 12b in opposite directions. The state of circulation is indicated by a broken arrow in FIG. 2A and the like. Moreover, when the direction of the blade | wing of a conveyance screw of each other is formed so that it may become reverse winding, both will be rotated in the same direction.

The third conveyance member 13 is configured as a conveyance screw formed to convey the developer in the opposite direction to the second conveyance member 12 in the third conveyance path 10c. The transport screw is formed as a helical thread 13a around the shaft 13b.
The third conveyance member 13 does not have to be stirred as long as it can convey the developer, as compared to the first conveyance member 11 and the second conveyance member 12, and may be, for example, merely in a screw shape. Of course, the threading portion 13a may be a blade as in the case of the first conveying member and the like. The threaded portion 13a and the shaft portion 13b are integrally molded of resin, or metal is used for part or all of the shaft portion 13b.

  The transport screw of the third transport member 13 is formed coaxially with the transport screw of the second transport member 12. That is, the shaft portion 12b and the shaft portion 13b are in series. The transport screws of the second transport member 12 and the third transport member 13 may be separately formed and then assembled, but are preferably integrally formed.

  Then, the third conveyance member 13 conveys the developer overflowing from the second conveyance path 10b to the third conveyance path 10c to the discharge port 10t provided in the third conveyance path 10c. Specifically, the threading portion 13a is formed in reverse winding with the blade portion 12a, and by rotating the shaft portions 12b and 13b, it becomes possible to transport the developer in the opposite direction to the blade portion 12a. ing.

  Here, the maximum outer diameter of the threaded portion 13a is formed smaller than the maximum outer diameter of the blade 12a (and the blade 12d described later). The reason for this is that the transport amount (that is, the discharge amount) in the third transport path 10c is smaller than the transport amount of the developer in the first transport path 10a or the second transport path 10b.

  For the same reason, it is preferable that the third conveyance path 10c be a substantially cylindrical conveyance path formed to have a smaller diameter than the second conveyance path 10b. When the developing device 1 is inclined, for example, by making the inner diameter of the third conveyance passage 10c smaller than the inner diameter of the second conveyance passage 10b and coaxial with the second conveyance passage 10b, for example, the second conveyance passage 10b It is possible to prevent in advance the situation where a large amount of developer overflows into the third conveyance path 10c and the developer is discharged more than necessary from the third conveyance path 10c.

  As described above, in the third conveyance path 10c, the developer is conveyed by the third conveyance member 13 to the discharge port 10t, and dropped from the discharge port 10t and discharged. The state of discharge is indicated by the double-dotted arrow in FIGS. 3A and 3B. Since the third conveyance path 10c is provided on the upstream side of the second conveyance path 10b in the conveyance direction of the developer, the discharge amount from the discharge port 10t is the development amount to be conveyed in the first conveyance path 10a and the second conveyance path 10b. It is less affected by the momentum of the agent, and it becomes easier to control the developer discharge amount.

  Although not shown, a container for recovering the discharged developer or a pipe connected to the container is attached to the discharge port 10t. Further, although the example in which the discharge port 10t is opened downward in the vertical direction when the developing device 1 is installed is given, it may be obliquely downward, sideways, or the like.

(Configuration in the vicinity of the connection portion between the second and third conveyance paths)
In the second transport member 12, the wing portions 12d and the wing portions 12a are formed at different pitches in the same winding direction. As compared with the blade portion 12a, the blade portion 12d is closer to the angle at which the surface pressing the developer and the shaft portion 12b are at a right angle. As a result, the action of pushing out the developer toward the outside of the outer periphery of the blade portion 12d is reduced, the transport force of the developer is weakened, the developer is retained, and the upper surface thereof is easily raised. Moreover, the pitch of the blade portions 12 d of the second conveyance member 12 is as short as about 5 mm as compared to the blade portions 12 a. The shorter the pitch, the more the retention amount of the developer can be.

  Further, the diameter of the blade portion 12d is formed to be about 15 mm, which is shorter than the diameter of the blade portion 12a of the second conveyance portion except for a part on the third conveyance path 10c side. On the other hand, the diameter of the blade portion 12d of the approximately one-turn portion on the third conveyance path 10c side is formed as large as approximately 16.5 mm. As a result, the developer easily enters the blade portion 12d from the first conveyance path 10a, and the developer discharged to the third conveyance path 10c side is not excessive when the flowability of the developer is good. ing.

  Then, as a configuration characterizing the present embodiment, the developer from the first conveyance path 10a to the second conveyance path 10b is located on the third conveyance path 10c side of the communication port 10ab of the first conveyance path 10a and the second conveyance path 10b. A block member 17 for restricting the flow is provided detachably. FIG. 6A is a view showing an example of the block member, and shows a block member 17 used for a medium speed machine. The block member 17 has a shape shown in FIG. 6A, and as shown in FIG. 4, the surface 17a on the first conveyance path 10a side is formed in an arc shape. Thereby, the block member 17 faces the blade portion 11 c of the first conveyance member 11 with a substantially constant gap. On the other hand, the upper surface 17b of the block member 17 on the second conveyance path 10b side is a predetermined region on the third conveyance path 10c side of the second conveyance path 10b, as shown in FIG. It has a substantially straight surface so that the notch K is formed. In FIG. 4, the notch K is shown as a portion where a part of the cylindrical inner wall is cut away.

  By providing the notch K, the gap (opening) between the blade portion 12 d of the second conveyance member 12 and the block member 17 can be expanded in the vicinity of the circulation junction in the second conveyance path 10 b. Since the opening by the notch K exists, for example, when the transport member is decelerated, etc., the developer stagnates excessively in the vicinity of the circulation junction in the second transport path 10b even if the flowability of the developer deteriorates. The developer can be smoothly discharged to the side of the third conveyance path 10c without causing the problem. Therefore, by changing the shape of the surface of the second conveyance path 10b of the block member 17, the amount of the developer to be discharged to the third conveyance path 10c side can be adjusted.

  Further, FIG. 6A shows a block member used for a medium speed machine, and a protruding portion in which the axial length L1 is short at the upper part of the height h or more of the base 17c with respect to the axial length L of the base 17c. The protrusion 17d is formed as 17d, and the flow of the developer from the first conveyance path 10a to the second conveyance path 10b is restricted by the protruding portion 17d of the axial length L1. For this reason, the developer stagnating at the downstream end in the transport direction of the first transport path 10a passes over the portion of the base 17c other than the projecting portion 17d even at the portion where the block member 17 is provided, and the second transport path It is pushed out to 10b.

  Therefore, by adjusting the axial length L of the base portion 17c of the block member 17, the axial length L1 of the projecting portion 17d, and the height h of the base portion 17c, the first conveyance path 10a to the second conveyance path 10b The developer flow rate can be adjusted. The axial length L1 of the projecting portion 17d of the block member 17 is about 60% or more of the axial length of the portion where the diameter of the blade portion 12d of the second conveyance member 12 is large, that is, one pitch ( It is desirable to form so as to be 3 mm or more which is 60% or more of about 5 mm), whereby excessive discharge of the developer from the second conveyance path 10 b to the third conveyance path 10 c can be prevented.

  FIG. 6B shows a block member 17 'for a high-speed machine, and in the axial direction of the projecting portion 17d' having a height h or more of the base 17c 'as compared with the block member 17 for medium-speed machine shown in FIG. The length L2 is as long as about 10 mm. Therefore, when the block member 17 'for high speed machine is used, the developer flow path from the first conveyance path 10a to the second conveyance path 10b becomes narrower than that of the medium speed block member 17 . Further, the block member 17 'for a high speed machine has a slightly arc-shaped surface 17b' on the second conveyance path side as compared with the block member 17 for a medium speed machine, and the notch K shown in FIG. To make it narrower. Thereby, the discharge amount of the developer from the second conveyance path 10 b to the third conveyance path 10 c side is limited compared to the block member 17 for the medium-sized machine. The shape of the surface 17 a ′ on the first conveyance path 10 a side of the block member 17 ′ for high-speed machines is the same as that of the block member 17 for medium-sized machines.

  Thus, for example, the block member 17 changes the amount of developer flowing from the first conveyance path 10a to the second conveyance path 10b by changing the axial length L1 of the projecting portion 17d which is equal to or greater than the height h of the base 17c. The amount of developer discharged from the second conveyance path 10b to the third conveyance path 10c can be adjusted by changing the surface shape on the second conveyance path side. For this reason, a plurality of types of block members are prepared for medium-speed machines or high-speed machines, and by changing the block members, a conveyance apparatus for medium-speed machines or a conveyance apparatus for high-speed machines is obtained. be able to. For this reason, in the present embodiment, as described later, the block member is detachably provided to the transport device.

  Further, in the present embodiment, the step member 16 is provided at the connection portion between the second conveyance path 10 b and the third conveyance path 10 c. As described above, the third conveyance path 10 c is a cylindrical conveyance path formed coaxially with the second conveyance path 10 b and smaller in diameter than the second conveyance path 10 b. Here, the step member 16 is provided at the position of the second conveyance path 10 b in the connection portion between the second conveyance path 10 b and the third conveyance path 10 c. FIG. 7A is a view showing an example of the step member, and shows the step member 16 used for a medium speed machine. The step member 16 is provided projecting in the direction of the shaft portion 12b of the second conveyance member 12 from a position coinciding with the inner wall surface of the third conveyance path 10c, and has an annular plate shape extending in the circumferential direction There is. The inner diameter φ1 of the annular plate portion is smaller than the inner diameter of the third conveyance path 10c, whereby a step is formed in the axial direction of the second conveyance member 12. The step is provided over the entire circumference of the inner wall surface of the second conveyance path 10b.

  As described above, in the second conveyance path 10b, since the step member 16 member is provided at the upstream end in the conveyance direction of the developer, the liquid surface of the developer in the second conveyance path 10b passes the step and the third conveyance path When it overflows to 10 c, the overflowing developer is conveyed by the third conveyance member 13 and travels to the discharge port 10 t. Since the step by the step member 16 is provided, for example, even if the developing device 1 is inclined, many developers do not overflow on the third conveyance path 10 c side, and waste is prevented from being discharged can do.

  Then, by changing the inner diameter of the annular plate portion of the step member 16, it is possible to adjust the amount of developer discharged from the second conveyance path 10b to the third conveyance path 10c over the level difference. FIG. 7B is a view showing another example of the step member, and shows a step member 16 ′ used in a high speed machine. The inner diameter φ2 of the annular plate portion of the step member 16 ′ for high speed machine is smaller than the inner diameter φ1 of the annular plate portion of the step member for medium speed machine, and the developer is excessively discharged in the high speed machine To prevent the developer from decreasing.

  Thus, by preparing a plurality of types of step members having different inner diameters of the annular plate-like members and changing the circular step members, a transfer device for a medium speed machine or a transfer device for a high speed machine can be obtained. You can get it. For this reason, in the present embodiment, as will be described later, the step member is detachably provided to the transport device in the same manner as the block member.

  FIG. 8 is an exploded perspective view of the right side of the drawing of the developing device shown in FIG. 1A. A method of detachably providing the block member 17 and the step member 16 to the developing device 1 will be described. A projection 10g is provided on the end face of the conveyance path main body member side (first and second conveyance path side) of the projecting member 10e which is the third conveyance path member, and a mounting hole is provided at a position corresponding to the projection 10g of the step member 16 16a is provided. Furthermore, mounting holes 17e are provided in the block member 17 at positions corresponding to the protrusions 10g, and the protrusions 10g of the protruding members are first fitted and fitted into the mounting holes 16a provided in the step member 16, and further The block member 17 and the step member 16 are attached to the projecting member 10 e by fitting into the attachment holes 17 e provided in the block member 17. In this state, the projecting member 10e is positioned and fixed to the transport path main body member.

  In the present embodiment, the block member 17 is detachably provided to the projecting member 10e, but the portion to which the block member 17 is fixed is not limited to the projecting member 10e. For example, while providing a projection or mounting hole on the lower surface of the base portion 17c of the block member 17, providing a mounting hole or projection on the lower bottom wall of the developing container 10 in which the first transport member 11 and the second transport member 12 are stored. Alternatively, the block member 17 may be detachably attached to the transport device by fitting the projection or attachment hole of the block member 17 with the attachment hole or projection of the lower bottom wall of the developer container 10. Further, since the block member 17 has a function of adjusting the discharge amount of the developer from the second conveyance path 10b to the third conveyance path 10c, only the block member 17 can be detachably attached to the conveyance device as necessary. The step member 16 may be formed integrally with the projecting member 10 e.

  In the conveyance device configured in this manner, the liquid surface of the developer is maintained at a height above the top of the shaft portions 11 b and 12 b of the first and second conveyance members 11 and 12 in a normal state. It is transported. Further, at the end portion of the second conveyance path 10b on the side of the third conveyance path 10c, retention of the developer is promoted by the blade portion 12d, and the liquid surface of the developer rises. As a result, the developer fills the notch K, which is the space between the block member 17 and the blade portion 12d of the second conveyance member 12 shown in FIG. 4, and the developer from the second conveyance path 10b to the third conveyance path 10c. Passage of Then, when the liquid surface of the developer in the second conveyance path 10 b exceeds the level difference due to the step member 16 and overflows in the third conveyance path 10 c, the overflowing developer is conveyed by the third conveyance member 13. Thus, the developer in the second conveyance path 10b can be discharged from the discharge port 10t via the third conveyance path 10c.

  In the present embodiment, as described above, the block member and the step member can be replaced according to the type of medium-sized machine, high-speed machine, etc. Therefore, the amount of developer in the developer container 10 according to the type You will be able to maintain it constantly and uniformly over the long term.

  Next, the trickle development system will be briefly described from the viewpoint of supply and discharge of the developer. The carrier in the toner bottle is mixed at a constant ratio, and the new carrier (unused carrier) is replenished into the developing device 1 at the same time the toner is replenished, while the deteriorated carrier is developed It is discharged from 1. However, not only the deteriorated carrier but also the developer in which the deteriorated carrier and the toner are mixed is discharged. Although the discharge of the developer has been described above, this means that the deteriorated carrier or the developer in which the deteriorated carrier and the toner are mixed is discharged.

  In this way, the degraded carrier is replaced with an unused carrier. Of course, only the deteriorated carrier is not necessarily replaced with the unused carrier, but basically, the developing device 1 is configured such that such replacement is performed.

  Specifically, in the developing device 1, when the toner is consumed by forming an image on a recording medium such as a sheet, the toner corresponding to the consumed amount is replenished. Therefore, for example, a toner concentration detection sensor (not shown) is provided at the bottom of the development container 10 as described above, and the toner concentration in the development container 10 (T is determined based on the detection result of the toner concentration detection sensor). / D: T is toner, D is a developer) is detected. Then, toner replenishment is controlled in accordance with the detected toner concentration.

  Generally, as a toner concentration detection sensor, a transmission type optical sensor, a reflection type optical sensor, or a magnetic permeability sensor is used. For example, it is preferable to use a permeability sensor. Permeability is the proportion of magnetic material in the developer. Therefore, when the mixing ratio of the magnetic material to the nonmagnetic material in the developer, that is, the relative concentration of the magnetic material changes, the output of the magnetic permeability sensor changes. Therefore, by detecting the magnetic permeability of the developer, the concentration of the carrier as the magnetic material in the developer is measured. Alternatively, the concentration of the nonmagnetic material toner in the developer is measured.

  In such a developing device 1, as described above, when replenishing unused toner from the toner bottle, the unused carrier is also replenished. Further, a part of the developer stored in the developing container 10 is discharged from the discharge port 10t. In this way, the degraded carrier is replaced with an unused carrier.

  The configuration of the developing device according to the present invention is not limited to the illustrated one, and may be, for example, a process cartridge provided with a photosensitive drum as an image carrier.

Second Embodiment
In the present embodiment, the block member and the step member used in the same model of the medium speed machine or the high speed machine are formed in the same system color. Specifically, it is formed in the same system color as the block member 17 for medium speed machine and the step member 16 for medium speed machine, and the block member 17 'for high speed machine and the step member 16' for high speed machine are the same. It is a systematic color and is formed with a systematic color different from that for medium speed machines. As a result, when the block member and the step member are incorporated into the transfer device according to the plurality of types of models, it is possible to select and attach the block member and the step member of the same system color. It is possible to prevent the set of members from being attached to the transport device.

Third Embodiment
FIG. 9 is a view showing an example of the arrangement of an image forming apparatus according to the present invention. This image forming apparatus can be mounted with the developing devices of the first and second embodiments, and forms an image on a recording medium by the developing device of the above embodiment and a developer supplied by the developing device. And a unit. The specific configuration of the image forming unit will be described below.

  The image forming apparatus according to the present embodiment is configured as a multifunction peripheral having a plurality of functions such as a scanner, a printer, and a copy. The image forming apparatus according to the present invention is not limited to the configuration exemplified here, and may be, for example, an image forming apparatus for single color printing or a single function printer.

  The image forming apparatus 100 forms an image on a recording sheet by electrophotography based on image data transmitted from the outside or read by a scanner (image reading apparatus). The apparatus body 101 and the automatic document processing apparatus 102 And consists of.

  The apparatus main body 101 includes an exposure unit 81, a developing unit 82, a photosensitive drum 83, a cleaner unit 84, a charger 85, an intermediate transfer belt unit 86, a fixing unit 87, a sheet feeding cassette 91a, a sheet discharge tray 94 and the like. Here, the developing device 82 corresponds to an example of the developing device according to the present invention. In addition, the apparatus main body 101 includes a control unit (not shown) that controls the entire image forming apparatus 100.

  A document placing table 96 made of transparent glass is provided on the upper part of the apparatus main body 101, and an automatic document processing apparatus 102 for automatically feeding the document on the document placing table 96 is attached on the upper side thereof. The automatic document processing apparatus 102 is configured to be rotatable in the direction of the arrow M, and by opening the top of the document placement table 96, a document can be placed manually.

  The apparatus main body 101 has an image reading apparatus 95 housed in a housing. The image reading device 95 is an image reading device of a reduction optical system including a light source unit 95a holding a light source and a first mirror, a mirror unit 95b holding a second and a third mirror, and a lens and a CCD 95c. . Further, the apparatus main body 101 is provided with an operation panel (not shown) so that the user can input an operation. Further, the apparatus main body 101 includes means for inputting image data from an externally connected apparatus, or means for reading image data from a portable recording medium (none of which is shown).

  The image data handled by the image forming apparatus 100 corresponds to a color image of four colors, for example, black (K), cyan (C), magenta (M), and yellow (Y). Therefore, four developing units 82, photosensitive drums (image carriers) 83, cleaner units 84 and chargers 85 are provided so as to form four types of latent images corresponding to the respective colors. An imaging station is configured. The developing devices 82 for the respective colors are connected to the toner bottles 90 for the respective colors through paths (not shown) so that the toners of the respective colors are supplied.

  The exposure unit 81 is configured as a laser scanning unit (LSU) including a laser emitting unit, a reflection mirror, and the like. The exposure unit 81 includes a polygon mirror for scanning a laser beam, and an optical element such as a lens or a mirror for guiding the laser beam reflected by the polygon mirror to the photosensitive drum 83. In addition, as the exposure unit 81, a method using a writing head in which light emitting elements are arranged in an array can also be adopted.

  The exposure unit 81 has a function of forming an electrostatic latent image according to image data on the surface of the charged photosensitive drum 83 by exposing the charged photosensitive drum 83 according to the input image data. The developing unit 82 visualizes the electrostatic latent images formed on the respective photosensitive drums 83 with toners of four colors (Y, M, C, K). The cleaner unit 84 also removes and collects the toner remaining on the surface of the photosensitive drum 83 after development and image transfer. The charger 85 is a charging means for uniformly charging the surface of the photosensitive drum 83 to a predetermined potential, and in addition to the charger type as shown in FIG. 5, a contact type roller type or brush type charger is used. It may be used.

  An intermediate transfer belt unit 86 disposed above the photosensitive drum 83 includes an intermediate transfer belt 86a, an intermediate transfer belt drive roller 86b, an intermediate transfer belt driven roller 86c, an intermediate transfer roller 86d, and an intermediate transfer belt cleaning unit 86e. Have. Four intermediate transfer rollers 86 d are provided corresponding to the respective colors of Y, M, C, and K. The intermediate transfer belt drive roller 86b, the intermediate transfer belt driven roller 86c, and the intermediate transfer roller 86d stretch the intermediate transfer belt 86a and drive it to rotate. Each intermediate transfer roller 86d provides a transfer bias for transferring the toner image on the photosensitive drum 83 onto the intermediate transfer belt 86a.

  The intermediate transfer belt 86 a is provided in contact with each photosensitive drum 83. Then, the color toner images (multicolor toner images) are formed on the intermediate transfer belt 86a by sequentially overlapping and transferring the toner images of the respective colors formed on the photosensitive drum 83 onto the intermediate transfer belt 86a. The intermediate transfer belt 86a is formed endlessly using, for example, a film having a thickness of about 100 μm to 150 μm.

  The transfer of the toner image from the photosensitive drum 83 to the intermediate transfer belt 86a is performed by an intermediate transfer roller 86d in contact with the back side of the intermediate transfer belt 86a. A high voltage transfer bias (a high voltage opposite in polarity (+) to the charging polarity (−) of the toner) is applied to the intermediate transfer roller 86 d in order to transfer the toner image. The intermediate transfer roller 86d is a roller based on a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm, and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, etc.). The conductive elastic material can apply a high voltage uniformly to the intermediate transfer belt 86a. In the present configuration example, a roller shape is used as the transfer electrode, but in addition to this, it is possible to use a brush or the like.

  As described above, the electrostatic images visualized according to the respective colors on the respective photosensitive drums 83 are stacked by the intermediate transfer belt 86a. The electrostatic images stacked in this manner are transferred onto the recording sheet by the transfer roller 88, which is a secondary transfer mechanism disposed at the contact position of a sheet described later and the intermediate transfer belt 86a, by the rotation of the intermediate transfer belt 86a. Ru. The secondary transfer mechanism unit is not limited to the transfer roller, but may be a corona charger or a transfer belt.

  At this time, the intermediate transfer belt 86a and the transfer roller 88 are in pressure contact with each other at a predetermined nip, and a voltage for transferring the toner to the sheet is applied to the transfer roller 88 (a reverse polarity to the charging polarity (−) of the toner) (+) High voltage). Furthermore, in order to obtain the above-mentioned nip regularly, as for the transfer roller 88, either one of the transfer roller 88 or the intermediate transfer belt drive roller 86b is made a hard material (metal etc.), and the other is a soft material (elasticity Rubber roller, foamable resin roller, etc.).

  Further, as described above, the toner attached to the intermediate transfer belt 86a by contacting the photosensitive drum 83, or the toner remaining on the intermediate transfer belt 86a without being transferred onto the recording paper by the transfer roller 88 is the next step. The intermediate transfer belt cleaning unit 86 e is set to be removed / collected in order to cause toner color mixture. The intermediate transfer belt cleaning unit 86e is provided with, for example, a cleaning blade as a cleaning member in contact with the intermediate transfer belt 86a, and the intermediate transfer belt 86a with which the cleaning blade contacts is supported by the intermediate transfer belt follower roller 86c from the back side. ing.

  The sheet feeding cassette 91 a is a tray for storing recording sheets (sheets) used for image formation, and is provided below the exposure unit 81 of the apparatus main body 101. Also, recording sheets used for image formation can be placed on the manual sheet feeding cassette 91b. A discharge tray 94 provided above the apparatus main body 101 is a tray for stacking recording sheets on which an image has been formed facedown.

  In the apparatus main body 101, a substantially vertical sheet conveyance path S1 for feeding the recording sheets of the sheet feeding cassette 91a and the manual sheet feeding cassette 91b to the sheet discharge tray 94 via the transfer roller 88 and the fixing unit 87. Is provided. In the vicinity of the sheet conveyance path S1 from the sheet feeding cassette 91a or the manual sheet feeding cassette 91b to the sheet discharge tray 94, pickup rollers 92a and 92b, a plurality of conveying rollers 93a to 93d, registration rollers 89, transfer rollers 88, and a fixing unit 87 mag is arranged.

  The conveyance rollers 93a to 93d are small rollers for promoting and assisting the conveyance of the recording sheet, and a plurality of the conveyance rollers 93a to 93d are provided along the sheet conveyance path S1. The pickup roller 92a is provided near the end of the sheet feeding cassette 91a, picks up recording sheets one by one from the sheet feeding cassette 91a, and supplies the sheet to the sheet conveyance path S1. Similarly, the pickup roller 92b is provided in the vicinity of the end of the manual sheet feeding cassette 91b, picks up recording sheets one by one from the manual sheet feeding cassette 91b, and supplies the sheet to the sheet conveyance path S1.

  Further, the registration roller 89 temporarily holds the recording sheet conveyed on the sheet conveyance path S1. The recording sheet is conveyed to the transfer roller 88 at the timing when the leading end of the toner image on the photosensitive drum 83 and the leading end of the recording sheet are aligned.

  The fixing unit 87 includes a heat roller 87a and a pressure roller 87b. The heat roller 87a and the pressure roller 87b are configured to rotate while sandwiching the recording sheet. The heat roller 87a is controlled to a predetermined fixing temperature on the basis of a signal from a temperature sensor (not shown), and is transferred onto the recording sheet by thermocompression bonding of the toner to the recording sheet together with the pressure roller 87b. It has a function to thermally fix the multicolor toner image on the recording paper. In addition, an external heating belt 87c for heating the heat roller 87a from the outside is provided.

  Next, the conveyance path of the recording paper will be described more specifically. As described above, the image forming apparatus 100 is provided with the sheet feeding cassette 91a for storing recording sheets in advance and the manual sheet feeding cassette 91b. Pickup rollers 92a and 92b are disposed to feed recording sheets from the sheet feeding cassettes 91a and 91b, respectively, and the recording sheets are guided one by one to the sheet conveyance path S1.

  The recording sheet conveyed from each of the sheet feeding cassettes 91a and 91b is conveyed to the registration roller 89 by the conveyance roller 93a of the sheet conveyance path S1, and the timing to align the leading end of the recording sheet with the leading end of the image information on the intermediate transfer belt 86a Then, the sheet is conveyed to the transfer roller 88, and the image information is written on the recording sheet. Thereafter, the recording sheet passes through the fixing unit 87, whereby the unfixed toner on the recording sheet is melted and fixed by heat, and is discharged onto the sheet discharge tray 94 through the conveying roller 93b disposed thereafter.

  The above conveyance path is for the single-sided printing request for the recording paper, but when the double-sided printing request is issued, the single-sided printing is completed as described above, and after the recording paper which has passed the fixing unit 87 When the end is gripped by the final conveyance roller 93b, the conveyance roller 93b reversely rotates to guide the recording sheet to the sheet conveyance path S2 in which the conveyance rollers 93c and 93d are disposed. The sheet conveyance path S2 joins the sheet conveyance path S1, and the recording sheet is conveyed from the registration roller 89 to the transfer roller 88. At this time, since the front and back of the recording sheet is reversed at the stage of joining the sheet conveyance path S2 to S1, the transfer roller 88 performs printing on the back surface of the recording sheet. Then, the recording sheet printed on the back side is fixed by the fixing unit 87 and discharged to the sheet discharge tray 94.

DESCRIPTION OF SYMBOLS 1 ... Development apparatus, 10 ... Development container, 10a ... 1st conveyance path, 10b ... 2nd conveyance path, 10c ... 3rd conveyance path, 10d, 10da ... Partition, 10e ... Protrusion member, 10f ... Supply port, 10g ... Projection 10t: discharge port, 10aa, 10ab: communication port, 11: first conveying member, 11a: blade portion of first conveying member, 11b: shaft portion of first conveying member, 11c: blade portion of first conveying member, 12: second conveying member 12a: blade of second conveying member 12b: shaft of second conveying member 12c: blade of second conveying member 12d: blade of second conveying member 13: second 3 Conveying member, 13a: Threaded portion, 13b: Shaft portion of third conveying member, 15: Developing roller, 15b: Shaft portion of developing roller, 16: Step difference member, 16a: Mounting hole, 17, 17 '... Block member, 17a, 17a ', 17b, 17b' ... surface, 17c 17c ': base, 17d, 17d': projecting portion, 17e: mounting hole, 81: exposure unit, 82: developing device, 83: photosensitive drum, 84: cleaner unit, 85: charging device, 86: intermediate transfer belt unit , 86a: intermediate transfer belt, 86b: intermediate transfer belt drive roller, 86c: intermediate transfer belt driven roller, 86d: intermediate transfer roller, 86e: intermediate transfer belt cleaning unit, 87: fixing unit, 87a: heat roller, 87b: addition Pressure roller, 87c: external heating belt, 88: transfer roller, 89: registration roller, 90: toner bottle, 91a: paper feed cassette, 91b: manual paper feed cassette, 92a: pickup roller, 92b: pickup roller, 93a, 93b , 93c, 93d: Transport roller, 94: Ejection tray, 95: Image reading Taking device, 95a: light source unit, 95b: mirror unit, 95c: CCD, 96: document placing table, 100: image forming apparatus, 101: apparatus main body, 102: automatic document processing apparatus.

Claims (7)

A conveyance device in which a first conveyance path and a second conveyance path are disposed in parallel, and a developer is circulated through communication openings provided at both ends of the first conveyance path and the second conveyance path,
A first conveyance member that conveys the developer while stirring the developer in the first conveyance path;
A second conveyance member that conveys the developer in the second conveyance path in a direction opposite to the first conveyance member while stirring the developer;
A transport path main body member accommodating the first transport member and the second transport member;
A third conveyance path connected to the second conveyance path on the upstream side in the conveyance direction of the developer in the second conveyance path;
The developer overflowing from the second conveyance path to the third conveyance path in the third conveyance path is conveyed in the opposite direction to the second conveyance member, and the developer is provided to the discharge port provided in the third conveyance path A third conveying member for conveying;
And a third conveyance path member that accommodates the third conveyance member and is positioned and fixed with respect to the conveyance path main body member.
A block member for restricting the flow of the developer from the first conveyance path to the second conveyance path is provided on the third conveyance path side of the communication port from the first conveyance path to the second conveyance path .
The block member is detachably attachable to the third conveyance path member by fitting a mounting hole provided in the block member to a projection provided on the conveyance path main body side of the third conveyance path member. A transport apparatus provided in The first transport path and the second transport path have a substantially cylindrical shape, and the block member has a predetermined length in the axial direction with respect to the first transport path and the second transport path. The side surface of the first conveyance path side faces the outer periphery of the first conveyance member with a fixed gap, and the side surface of the block member on the second conveyance path side has a shape in which a notch is formed in the upper part on the communication port side The transport apparatus according to claim 1, further comprising: The third transport path is a cylindrical transport path formed coaxially with the second transport path and smaller in diameter than the second transport path, and the end portion of the third transport path and the block It further has an annular plate-like step member for adjusting the inflow of the developer conveyed into the third conveyance path between the member and the third conveyance passage, and the step member is detachably attachable to the third conveyance path member conveying apparatus according to claim 1 or 2, characterized in that provided in the. The step member is detachably attachable to the third conveyance path member by fitting an attachment hole provided in the step member to a projection provided on the conveyance path main body side of the third conveyance path member. The transport apparatus according to claim 3 , wherein the transport apparatus is provided in The conveyance device according to claim 3 or 4 , wherein the block member and the step member are formed in the same system color. A developing device comprising the transport device according to any one of claims 1 to 5 and a developer carrier, wherein the developer is supplied to the developer carrier by the second transport member. A developing device characterized by An image forming apparatus comprising: the developing device according to claim 6 ; and an image forming unit for forming an image on a recording medium by the developer supplied by the developing device.

Images