JP6953833B2 - Develop equipment and image forming equipment - Google Patents

Description

The present invention relates to a developing device and an image forming device. More specifically, the present invention relates to a developing apparatus and an image forming apparatus capable of making the amount of the developing agent held in the developing agent holding member uniform.

Electrophotographic image forming devices include MFPs (Multifunction Peripheral) equipped with scanner functions, facsimile functions, copying functions, printer functions, data communication functions, and server functions, facsimile machines, copiers, printers, and the like. be.

An electrophotographic image forming apparatus generally develops an electrostatic latent image formed on an image carrier using a developing apparatus to form a toner image, transfers the toner image to paper, and then uses a fixing device. An image is formed on the paper by fixing the toner image on the paper. Further, in the image forming apparatus, the electrostatic latent image on the surface of the photoconductor is developed by using a developing apparatus to form a toner image, and the toner image is transferred to an intermediate transfer belt by using a primary transfer roller. In some cases, the toner image on the intermediate transfer belt is secondarily transferred to paper using a secondary transfer roller. In this case, the photoconductor and the intermediate transfer belt serve as the image carrier.

The developing apparatus includes a developing tank, a toner replenishing unit, a developer composed of toner and carriers, a stirring and transporting member, a developing agent holding member (mag roller), a regulating member, and the like. The toner supplied to the developing tank by the toner replenishing unit is agitated and conveyed together with the developer in the developing tank by the stirring and transporting member. The developer is supplied onto the image carrier via a developer holding member that rotates after reaching a predetermined charge amount, and development is performed.

When the developer held by the developer holding member passes through the gap between the blade-shaped regulating member and the developing agent holding member, an excess amount is scraped off by the regulating member. As a result, the amount of the developer conveyed by the developer holding member becomes uniform.

The developing tank is divided into a supply tank and a stirring tank by a partition wall. The partition wall extends along the rotation axis of the developer holding member, and the developer is transferred between the supply tank and the stirring tank at both ends along the rotation axis of the developer holding member. There is an opening for this. Rotating stirring and transporting members such as screws are arranged in each of the supply tank and the stirring tank. As a result, the developer is circulated and transported along the transfer path inside the supply tank and the stirring tank.

In recent years, the manufacturing cost has been reduced by reducing the amount of the developer contained in the developing tank in the developing apparatus. However, if the amount of the developer contained in the developing tank is reduced, the circulating amount of the developing agent circulating in the developing tank is reduced. In that case, when the toner consumption of the image forming apparatus on which the developing apparatus is mounted is large, the toner concentration in the developing agent held by the developing agent holding member fluctuates (tilts, in the longitudinal direction) in the rotation axis direction (longitudinal direction). Unevenness) is likely to occur, which causes density unevenness in an image formed by using a developing device.

As a method for preventing the occurrence of density unevenness, a method of increasing the circulation speed of the developer by increasing the rotation speed of the screw is generally used. However, this method has a problem that the torque of the developing device increases due to the increase in the rotation speed of the screw, and a problem that the toner is melted by the heat generated by the rotation of the screw and the developing device is easily damaged.

Therefore, in the following Patent Document 1 and the like, a technique for suppressing fluctuations in the toner concentration in the developer held by the developer holding member in the direction of the rotation axis is proposed. In Patent Document 1 below, the number of openings provided in the partition wall for partitioning the developing tank is increased to branch the developing agent circulation path, so that the developing agent can be supplied to the supply tank even from the middle of the developing agent circulation path. The technology that makes it possible to supply is disclosed.

Japanese Unexamined Patent Publication No. 2009-236964

In the configuration in which the circulation path is branched as in Patent Document 1, since openings are provided in portions other than both ends of the partition wall, the height difference of the liquid level of the developer in the supply tank becomes large, and the developer holding member The amount of developer retained in is uneven in the direction of rotation.

FIG. 12 is a diagram schematically showing a variation in the amount of the developer held by the developer holding member in the rotation axis direction of the developer holding member. The middle line L21 in FIG. 12 shows the variation in the amount of the developer held in the developer holding member before passing through the regulating member when the amount of the developer in the developing tank is sufficiently large. FIG. 12 center line L22 shows the variation in the amount of the developer held in the developer holding member before passing through the regulating member when the amount of the developer in the developing tank is small. FIG. 12 center line L23 shows fluctuations in the amount of developer held in the developer holding member after passing through the regulating member (in other words, truly) when the amount of developer in the developing tank is sufficiently large. The amount of developer required) is shown.

With reference to FIG. 12, in a configuration in which the amount of developer contained in the developing tank is sufficiently large, the developer retained in the developer holding member is homogenized as it passes through the restricting member and is truly required. Since the amount is adjusted to a large amount, the unevenness in the amount of the developing agent is eliminated (FIG. 12, middle line L21 → line L23). However, in the configuration in which the amount of the developing agent contained in the developing tank is reduced, the unevenness in the amount of the developing agent is not eliminated (FIG. 12, middle line L22).

FIG. 13 shows the variation in the rotation axis direction of the developer holding member in the ratio of the amount of the developer excessively supplied to the developer holding member to the minimum value of the amount of the developer excessively supplied to the developer holding member. It is a figure which shows typically. The middle line L41 in FIG. 13 shows the ratio when the amount of the developer in the developing tank is sufficiently large. The middle line L42 in FIG. 13 shows the ratio when the amount of the developer in the developing tank is small.

With reference to FIGS. 12 and 13, the amount of developer held in the developer holding member (when the amount of developer in the developing tank is sufficiently large: center line L21 in FIG. 12, of the developing agent in the developing tank. When the amount is small: By subtracting the truly required amount of developer (center line L23 in FIG. 12) from the center line L22 in FIG. 12, the amount of the developer excessively supplied to the developer holding member in the rotation axis direction Find the variation (when the amount of developer in the developing tank is sufficiently large: the amount indicated by arrows L31a and L31b in FIG. 12, and when the amount of developing agent in the developing tank is small: indicated by the middle lines L32a and 32b in FIG. amount).

Next, the minimum value of the amount of the developer excessively supplied to the developer holding member (when the amount of the developer in the developing tank is sufficiently large: the amount indicated by the arrow L31a in FIG. 12, the developing agent in the developing tank). When the amount of the developer is small: The variation in the rotation axis direction of the ratio of the amount of the developer excessively supplied to the developer holding member with respect to the amount indicated by the middle line L32a in FIG. 12 is obtained (the amount of the developer in the developing tank is When the amount is sufficiently large: center line L41 in FIG. 13, when the amount of the developer in the developing tank is small: center line L42 in FIG. 13). As a result, the amount of variation in the rotation axis direction of the ratio of the amount of the developer excessively supplied to the developer holding member to the minimum value of the amount of the developer excessively supplied to the developer holding member is in the developing tank. It becomes larger when the amount of the developer is small.

Here, by observing the behavior of the developer in the vicinity of the regulating member in detail, even if the distance between the regulating member and the developer holding member is constant, if the density of the developing agent passing through is different, the developer passes through the regulating member. It is known that the amount of developer is different. It is known that the density of the developer increases in proportion to the amount of the developer excessively supplied to the developer holding member.

That is, if the amount of the developer excessively supplied to the developer holding member is large, the developer passing through the regulator member receives a force in the direction of being compressed by the excessively supplied developer, and thus passes through the regulator member. The density of the developing agent is increased, and the amount of the developing agent passing through the regulating member is increased. Therefore, in the conventional configuration in which the amount of the developer in the developing tank is sufficiently large, the unevenness in the amount of the developing agent held in the developing agent holding member in the rotation axis direction is eliminated. On the other hand, in the configuration where the amount of the developer in the developing tank is small, the developer passing through the regulating member is received from the excessively supplied developer at the place where the amount of the developer held by the developer holding member is small. The force is reduced and the density of the developer passing through the regulatory member is not increased. As a result, the amount of the developer passing through the regulating member did not increase, and the unevenness of the amount of the developer held in the developer holding member in the rotation axis direction of the developer holding member was not eliminated.

The present invention is for solving the above problems, and an object of the present invention is to provide a developing device and an image forming device capable of making the amount of the developing agent held in the developing agent holding member uniform. be.

The developing apparatus according to one aspect of the present invention is a developing apparatus for developing an electrostatic latent image formed on an image carrier, and has a housing for accommodating a developer and housings for a first accommodating chamber and a second accommodating chamber. A partition wall partitioning the containment chamber, the partition wall including the three or more openings, and a plurality of transport paths formed by the three or more openings inside the first and second containment chambers. A transport means that circulates and conveys the developer along the line, and a developer holding member that rotates around the axis of rotation. The developer is acquired from the inside of the second storage chamber, and the acquired developer is applied to the outer peripheral surface. A developer holding member that guides the developer to the developing region facing the image carrier while holding the image, a first regulating member that regulates the amount of the developing agent that is guided to the developing region by the developing agent holding member, and a first regulating member. On the upstream side in the rotational direction of the developer holding member, a second regulating member for regulating the amount of the developing agent guided to the developing region by the developing agent holding member is provided , and three or more openings are provided with a second accommodating member. Arranged along the direction of transport of the developer inside the chamber, three or more openings are provided on one end side of the partition wall in the direction of rotation, from the first containment chamber to the second. An end inlet, which is an inlet of the developer to the containment chamber, and a developer flow from the second containment chamber to the first containment chamber, which are provided on the other end side of the partition wall in the rotation axis direction. It includes an end outlet, which is an outlet, and an intermediate circulation port provided between the end inlet and the end outlet in the partition wall, and the intermediate circulation port is in three or more openings arranged. Then, in the first intermediate circulation port, which is an opening adjacent to the end inflow port on the upstream side in the developing agent transport direction inside the second storage chamber, and in three or more arranged openings. The second intermediate circulation port, which is an opening adjacent to the first intermediate circulation port on the upstream side in the developing agent transport direction inside the second storage chamber, is included, and the end inflow port and the second The amount of the developing agent regulated by the second regulating member at the position corresponding to the portion of the partition wall sandwiched between the first intermediate circulation port and the first intermediate circulation port is sandwiched between the first intermediate circulation port and the second intermediate circulation port. The amount of the developer regulated by the second regulating member at the position corresponding to the portion of the partition wall.

A developing apparatus according to another aspect of the present invention is a developing apparatus that develops an electrostatic latent image formed on an image carrier, and has a housing for accommodating a developer and housings for a first accommodating chamber and a second accommodating chamber. A partition wall partitioning the containment chamber, the partition wall including the three or more openings, and a plurality of transport paths formed by the three or more openings inside the first and second containment chambers. A transport means that circulates and conveys the developer along the line, and a developer holding member that rotates around the axis of rotation. The developer is acquired from the inside of the second storage chamber, and the acquired developer is applied to the outer peripheral surface. A developer holding member that guides the developer to the developing region facing the image carrier while holding the image, a first regulating member that regulates the amount of the developing agent that is guided to the developing region by the developing agent holding member, and a first regulating member. On the upstream side of the developer holding member in the direction of rotation, a second regulating member that regulates the amount of developer guided to the developing region by the developer holding member is provided, and three or more openings are rotated in the partition wall. An end inlet, which is provided on one end side in the axial direction and is an inlet of the developer from the first storage chamber to the second storage chamber, and the other end side in the rotation axis direction of the partition wall. On the way between the end outlet, which is the outlet of the developer from the second storage chamber to the first storage chamber, and the end inlet and the end outlet of the partition wall. The shape of the second regulating member in the rotation axis direction, including the circulation port, changes at a position corresponding to the circulation port on the way, and in the direction of the rotation axis in the second storage chamber, the liquid level during transport of the developing agent. The amount of the developing agent regulated by the second regulating member at a position where the height is higher than the height of the liquid level when the developing agent is not conveyed by the first difference or more is determined in the rotation axis direction in the second accommodating chamber. The amount of the developing agent regulated by the second regulating member is larger than the amount of the developing agent regulated by the second regulating member at a position where the height of the liquid level when the developing agent is conveyed is lower than the height of the liquid level when the developing agent is not conveyed by a second difference or more.

Preferably, in the developing apparatus, the second restricting member includes a plurality of regulating portions provided at intervals in the rotation axis direction, and each of the plurality of regulating portions is provided in the rotation axis direction in the second accommodating chamber. At a position where the height of the liquid level when the developer is transported is higher than the height of the liquid level when the developer is not transported by a first difference or more.

In the developing apparatus, preferably, the second regulating member extends continuously in the rotation axis direction, and the distance between the second regulating member and the developer holding member is the rotating shaft in the second accommodating chamber. It changes according to the change in the height of the liquid level when the developer is conveyed in the direction.

Preferably, in the developing apparatus, the intermediate circulation port includes an intermediate inflow port which is an inflow port of the developer from the first accommodating chamber to the second accommodating chamber, and the second regulating member and the developing agent holding member. The spacing decreases along the developer transport direction at a position corresponding to the midway inlet in the axis of rotation.

Preferably, in the developing apparatus, the intermediate circulation port includes an intermediate outlet which is an outlet of the developer from the second accommodating chamber to the first accommodating chamber, and the second regulating member and the developing agent holding member. The spacing increases along the developer transport direction at positions corresponding to the midstream outlets in the direction of rotation.

In the above-mentioned developing apparatus, preferably, the conveying means includes a shaft extending in the direction of the rotation axis and rotating, and a blade member spirally provided on the outer peripheral surface of the shaft, and the diameter of the shaft and the second accommodating chamber. At least one of the sizes of the cross-sectional area of the cross section orthogonal to the rotation axis of is changed at the position corresponding to the intermediate circulation port in the rotation axis direction.

Preferably, in the developing apparatus, the conveying means further includes a paddle provided at a position corresponding to an intermediate circulation port in the rotation axis direction on the outer peripheral surface of the shaft in the second accommodating chamber.

In the above developing apparatus, preferably, the number of blade members in the second accommodating chamber corresponds to each other at a position corresponding to the position of the intermediate circulation port in the rotation axis direction and a position not corresponding to other than the intermediate circulation port in the rotation axis direction. different.

In the developing apparatus, preferably, the maximum value of the distance between the second regulating member and the developer holding member at the position corresponding to the partition wall in the rotation axis direction is set to a value C, and the position corresponding to the intermediate circulation port in the rotation axis direction. When the minimum value of the distance between the second regulating member and the developer holding member is set to the value D, the relationship of 1.5 × C ≧ D> C holds between the value C and the value D.

In the developing apparatus, preferably, the maximum value of the distance between the first regulating member and the developer holding member is set to a value A, and the maximum value of the distance between the second regulating member and the developing agent holding member is set to a value B. , The relationship of 2 × A ≧ B> A holds between the value A and the value B.

An image forming apparatus according to still another aspect of the present invention includes the above-mentioned developing apparatus and a transfer means for transferring an electrostatic latent image developed by the developing apparatus onto paper.

According to the present invention, it is possible to provide a developing device and an image forming device capable of making the amount of the developing agent held on the developing agent holding member uniform.

It is sectional drawing which shows the structure of the image forming apparatus 100 in 1st Embodiment of this invention. It is an enlarged view around the developing apparatus 31 in FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. It is sectional drawing which shows the structure of the developing apparatus of a comparative example. It is a figure which shows the distribution of the amount of the developer held on the mag roller 52 in the comparative example in the rotation axis R direction. It is a figure which shows the distribution of the amount of the developer held on the mag roller 52 of the developing apparatus 31 of 1st Embodiment of this invention in the rotation axis R direction. It is a figure which shows the structure of the pre-regulatory member 56 in the 2nd Embodiment of this invention. It is a figure which shows the structure of the pre-regulatory member 56 in the 3rd Embodiment of this invention. It is a figure which shows the structure of the pre-regulatory member 56 in 4th Embodiment of this invention. It is sectional drawing which shows the structure of the developing apparatus 31 in 5th Embodiment of this invention. It is sectional drawing which shows the structure of the developing apparatus 31 in 6th Embodiment of this invention. It is a figure which shows typically the variation in the rotation axis direction of the developer holding member of the amount of the developer held by the developer holding member. The variation in the rotation axis direction of the developer holding member in the ratio of the ratio of the amount of the developer excessively supplied to the developer holding member to the minimum value of the amount of the developer excessively supplied to the developer holding member is shown. It is a figure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the following embodiment, the case where the image forming apparatus is an MFP will be described. The image forming apparatus may be a facsimile apparatus, a copying machine, a printer, or the like, in addition to the MFP.

[First Embodiment]

First, the configuration of the image forming apparatus according to the present embodiment will be described.

FIG. 1 is a cross-sectional view showing the configuration of the image forming apparatus 100 according to the first embodiment of the present invention.

With reference to FIG. 1, the image forming apparatus 100 in the present embodiment is an MFP, and mainly includes a paper conveying unit 10, a toner image forming unit 30, and a fixing device 40.

The paper transport unit 10 includes a paper feed tray 11, a paper feed roller 13a, a paper transport roller 13b, a paper discharge roller 13c, and a paper discharge tray 14. The paper feed tray 11 is provided in the lower part of the image forming apparatus main body 100a, and accommodates the paper P for forming an image. There may be a plurality of paper feed trays 11. The paper feed roller 13a is provided between the paper feed tray 11 and the transport path TR. The transport roller 13b is provided in the transport path TR. The paper ejection roller 13c is provided at the most downstream portion of the transport path TR. The output tray 14 is provided outside the image forming apparatus main body 100a.

The toner image forming unit 30 synthesizes four color images of Y (yellow), M (magenta), C (cyan), and K (black) by a so-called tandem method, and transfers the toner image to paper. The toner image forming unit 30 is intermediate between the YMCK color developing devices 31a, 31b, 31c, and 31d (an example of a developing device), the YMCK color photoconductor units 32a, 32b, 32c, and 32d, and the exposure device 33. It includes a transfer belt 34, primary transfer rollers 35a, 35b, 35c, and 35d, a secondary transfer roller 36 (an example of transfer means), a cleaning device 37, a rotary roller 39, and the like.

In the present specification, the developing devices 31a, 31b, 31c, and 31d may be collectively referred to as a developing device 31, and the photoconductor units 32a, 32b, 32c, and 32d may be collectively referred to as a photoconductor unit 32.

The developing device 31 and the photoconductor unit 32 of each color are juxtaposed directly below the intermediate transfer belt 34. The photoconductor unit 32 includes a photoconductor drum 81 (an example of an image carrier), a charging device 82, and a cleaning device 83.

The photoconductor drum 81 has photoconductivity and is cylindrical. The photoconductor drum 81 is rotationally driven in the direction indicated by the arrow AR1 in FIG. A charging device 82, a developing device 31, and a cleaning device 83 are arranged around the photoconductor drum 81. The charging device 82 is for charging the photoconductor drum 81, and the surface potential of the photoconductor drum 81 is set to a predetermined charging potential by the charging device 82. Each of the four developing devices 31 contains toner of each color of YMCL and develops an electrostatic latent image formed on the photoconductor drum 81. The cleaning device 83 removes waste toner on the photoconductor drum 81.

The exposure apparatus 33 is provided below the developing apparatus 31 and the photoconductor unit 32 for each color. The intermediate transfer belt 34 has an endless shape and is bridged over a rotating roller 39. The intermediate transfer belt 34 is rotationally driven in the direction indicated by the arrow AR2 in FIG. Each of the primary transfer rollers 35a, 35b, 35c, and 35d faces each of the photoconductor drums 81 in the photoconductor unit 32 of each color with the intermediate transfer belt 34 interposed therebetween. The secondary transfer roller 36 is in contact with the intermediate transfer belt 34 in the transfer path TR. The distance between the secondary transfer roller 36 and the intermediate transfer belt 34 can be adjusted by a pressure contact separation mechanism (not shown). The cleaning device 37 is provided in the vicinity of the intermediate transfer belt 34.

The fixing device 40 includes a heating roller 41 and a pressure roller 42. The fixing device 40 fixes the toner image on the paper by transporting the paper carrying the toner image along the transport path TR while grasping the paper carrying the toner image by the nip portion of the heating roller 41 and the pressure roller 42.

When the image forming apparatus 100 receives the print request, the paper transport unit 10 feeds the paper (recording sheet) P stored in the paper feed tray 11 into the transport path TR by the paper feed roller 13a. The paper transport unit 10 transports the paper along the transport path TR by the transport roller 13b (timing roller), and guides the paper between the intermediate transfer belt 34 and the secondary transfer roller 36 at a predetermined timing.

The charging device 82 charges the surface of the rotating photoconductor drum 81 to a predetermined charging potential. The exposure apparatus 33 irradiates the surface of the photoconductor drum 81 charged with a predetermined charging potential with an exposure beam based on the image information requested to be printed. As a result, an electrostatic latent image is formed on the surface of the photoconductor drum 81. The developing device 31 supplies toner to the surface of the photoconductor drum 81 to develop an electrostatic latent image formed on the surface of the photoconductor drum 81. The developed electrostatic latent image becomes a toner image. Each of the primary transfer rollers 35a, 35b, 35c, and 35d sequentially transfers the toner image formed on the photoconductor drum 81 of the photoconductor unit 32 of each color to the surface of the intermediate transfer belt 34 (primary transfer). A toner image in which toner images of each color are combined is formed on the surface of the intermediate transfer belt 34. The cleaning device 83 removes the toner remaining on the photoconductor drum 81 without being transferred to the intermediate transfer belt 34.

The rotary roller 39 rotationally drives the intermediate transfer belt 34. As a result, the toner image formed on the surface of the intermediate transfer belt 34 is conveyed to a position facing the secondary transfer roller 36. The secondary transfer roller 36 transfers the toner image formed on the surface of the intermediate transfer belt 34 to the paper conveyed between the intermediate transfer belt 34 and the secondary transfer roller 36. The cleaning device 37 removes and recovers the toner remaining on the surface of the intermediate transfer belt 34 without being transferred to the paper.

The paper on which the toner image is transferred is guided to the fixing device 40. The fixing device 40 fixes the toner image on the paper. After that, the paper transport unit 10 discharges the paper on which the toner image is fixed to the paper ejection tray 14 by the paper ejection roller 13c.

The image forming apparatus 100 is not limited to the one having the above-described configuration, and the rotary developing apparatus holding a plurality of developing apparatus is rotated so that each developing apparatus is sequentially guided to the photoconductor drum in full color. A full-color image forming apparatus for forming an image of the above, or an image forming apparatus for forming a black-and-white image may be used.

FIG. 2 is an enlarged view of the vicinity of the developing device 31 in FIG. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. It should be noted that the development agent is not shown in the drawings.

With reference to FIGS. 2 and 3, the developing apparatus 31 includes a housing 51, a mag roller 52 (an example of a developer holding member), a partition wall 60, a stirring screw 53, a supply screw 54, and a regulating member 55. (An example of a first regulatory member) and a pre-regulatory member 56 (an example of a second regulatory member) are included.

The housing 51 houses the developer. A discharge port 51a for discharging the developing agent from the inside of the housing 51 is provided near the right end portion in FIG. 3 of the housing 51.

The mag roller 52 has a cylindrical shape and is arranged so as to face the photoconductor drum 81 with a required interval. The mag roller 52 is supported by the housing 51. The mag roller 52 includes a rotary sleeve 52a and a magnet member 52b provided on the inner peripheral side of the rotary sleeve 52a. The rotary sleeve 52a has a cylindrical shape and rotates around the rotation axis R in the direction indicated by the arrow AR3. The magnet member 52b has a cylindrical shape, and its outer peripheral surface is magnetized alternately with north and south poles along the circumferential direction. The mag roller 52 acquires the developer from the inside of the supply tank SP2, and guides the acquired developer to the developing region RG facing the photoconductor drum 81 while holding the acquired developer on the outer peripheral surface of the sleeve 52a by the magnetic force of the magnet member 52b. ..

The partition wall 60 is provided inside the housing 51 and extends along the rotation axis R. The partition wall 60 partitions the inside of the housing 51 into a stirring tank SP1 (an example of a first storage chamber) and a supply tank SP2 (an example of a second storage chamber). Both the stirring tank SP1 and the supply tank SP2 extend along the rotation axis R. The partition wall 60 includes three or more openings 61a, 61b, 61c, 61d, 61e, and 61f. The partition wall 60 is separated into five by each of the openings 61a, 61b, 61c, 61d, 61e, and 61f. The opening 61a is an end inlet provided at one end of the partition wall 60 in the rotation axis R direction, and the opening 61f is an end provided at the other end of the partition wall 60 in the rotation axis R direction. It is a part outlet. Each of the openings 61b, 61c, 61d, and 61e is an intermediate circulation port provided between the opening 61a and the opening 61f, and is provided in this order from the side closer to the opening 61a.

Each of the stirring screw 53 and the supply screw 54 (an example of the conveying means) is provided in each of the stirring tank SP1 and the supply tank SP2, and the developer is mixed and stirred by rotating in the directions indicated by the arrows AR4 and AR5, respectively. Transport while transporting. Each of the stirring screw 53 and the supply screw 54 has substantially the same shape except that the length of the stirring screw 53 in the rotation axis direction is longer than the length of the supply screw 54 in the rotation axis direction. The blade member 72 and the paddle 73 are included. The shaft 71 extends in the rotation axis R direction and rotates. The shaft 71 is rotatably supported with respect to the housing 51. The blade member 72 is spirally provided on the outer peripheral surface of the shaft 71. The paddle 73 has a plate shape and is provided at a predetermined position on the outer peripheral surface of the shaft 71.

As an example of each size of the stirring screw 53 and the supply screw 54, the outer diameter of each of the stirring screw 53 and the supply screw 54 is 12 mm, and the shaft diameter is 6 mm.

The regulating member 55 has a plate shape and extends continuously parallel to the rotation axis R. The regulating member 55 is fixed to the housing. The end of the regulating member 55 on the side close to the mag roller 52 (the end in the direction perpendicular to the rotation axis R) faces the S pole of the magnet member 52b, and is spaced from the outer peripheral surface of the mag roller 52. They are facing each other via T. The regulating member 55 regulates the amount of the developer guided to the developing region RG by the mag roller 52.

The pre-regulatory member 56 has a plate shape and extends continuously parallel to the rotation axis R. The pre-regulatory member 56 is fixed to the housing 51. The pre-regulatory member 56 regulates the amount of the developer guided to the developing region RG by the mag roller 52 at a position upstream of the regulating member 55 in the rotational direction of the mag roller 52.

A toner replenishment unit (not shown) is provided in the lower right part of FIG. 3 in the housing 51, and toner is supplied from a sub-hopper (not shown) into the stirring tank SP1 through the toner replenishment unit.

The stirring screw 53 and the supply screw 54 circulate and transport the developer inside the housing 51 along a plurality of transport paths formed by the openings 61a, 61b, 61c, 61d, 61e, and 61f.

Specifically, the stirring screw 53 conveys the developer from the right side to the left side in FIG. 3 in the stirring tank SP1 as shown by the arrow D1, and the supply screw 54 is carried in the supply tank SP2 as shown by the arrow D2. The developer is conveyed from the left side to the right side in FIG. The developer flows into the supply tank SP2 from the stirring tank SP1 through the opening 61a as shown by the arrow D3, and flows out from the supply tank SP2 to the supply tank SP1 through the opening 61f as shown by the arrow D4. As a result, a long annular transport path (the transport path indicated by the solid arrow in FIG. 3) is constructed.

On the other hand, the openings 61b, 61c, 61d, and 61e, which are intermediate circulation ports, are branched or merged with respect to a long annular transport path (the transport path indicated by the solid arrow in FIG. 3) (dotted line in FIG. 3). The transport path indicated by the arrow) is configured. The intermediate circulation ports are openings 61c and 61e constituting the intermediate inlet, which is the inlet of the developer from the stirring tank SP1 to the supply tank SP2, and the outlet of the developer from the supply tank SP2 to the stirring tank SP1. It is divided into openings 61b and 61d that form an intermediate outlet.

Specifically, as shown by the arrow D5, a part of the developer conveyed by the stirring screw 53 passes through each of the openings 61c and 61e, which are intermediate inflow ports, before reaching the opening 61a, and the stirring tank SP1 Flows into the supply tank SP2. In other words, the long annular transport path branches from the flow path in the stirring tank SP1 at each position of the openings 61c and 61e and joins the flow path in the supply tank SP2.

Similarly, a portion of the developer conveyed by the supply screw 54 is agitated from the supply tank SP2 through each of the midway outlets 61b and 61d before reaching the opening 61f, as indicated by arrow D6. It flows out to the tank SP1. In other words, the long annular transport path branches off from the supply tank SP2 at each position of the openings 61b and 61d and joins the stirring tank SP1.

By supplying a new developer in the middle of the long annular transport path described above, it is possible to suppress fluctuations in the amount of the developer along the rotation axis R direction.

The length of each of the plurality of openings 61a, 61b, 61c, 61d, 61e, and 61f in the vertical direction in FIG. 2 is, for example, 20 mm. The length of the partition wall 60 existing between the openings along the rotation axis R is, for example, 20 mm. Each of the plurality of openings 61a, 61b, 61c, 61d, 61e, and 61f has a partition wall 60 from substantially the same height as the lower surface of the shaft 71 of the stirring screw 53 and the supply screw 54 to substantially the same height as the upper surface of the housing 51. It is provided in.

The amount of the developer conveyed in the directions indicated by the arrows D3 and D4 is larger than the amount of the developer conveyed in the directions indicated by the arrows D5 and D6 described later. For this reason, the arrows D3 and D4 are indicated by double arrows.

If the amount of the developer inside the housing 51 becomes excessive, the excess developer is discharged from the discharge port 51a. The discharge port 51a may not be provided.

By the way, it is possible to move the developer between the stirring tank SP1 and the supply tank SP2 just by providing the opening, but the paddle is attached to the screw on the feed side at the position corresponding to the opening in the rotation axis R direction. By providing the developer, the feed amount of the developer can be increased, and the flow of the developer in a fixed direction can be created. In this case, it is better to install a paddle on the sending side (branch side) and not to install a paddle on the receiving side (merging side).

Specifically, the paddle 73 of the stirring screw 53 is provided at a position corresponding to each of the openings 61c and 61e in the rotation axis R direction, and serves to convey the developer from the stirring tank SP1 to the supply tank SP2. Fulfill. The paddle 73 of the supply screw 54 is provided at a position corresponding to each of the openings 61b and 61d in the rotation axis R direction, and serves to convey the developer from the supply tank SP2 to the stirring tank SP1.

The paddle 73 is a flat plate parallel to the shaft 71, and has a width (length in the horizontal direction in FIG. 3) of each of the openings 61a, 61b, 61c, 61d, 61e, and 61f in the rotation axis R direction. Has a width. The paddle 73 has substantially the same height (length in the vertical direction in FIG. 3) as the outer diameter of each of the stirring screw 53 and the supply screw 54. Although only one paddle 73 is provided here in the circumferential direction, a plurality of paddles 73 may be provided in the circumferential direction.

The supply screw 54 supplies the developer in the supply tank SP2 to the outer peripheral surface of the mag roller 52 (the outer peripheral surface of the rotary sleeve 52a) while conveying the developer. The mag roller 52 rotates in the direction indicated by the arrow AR3 to convey the supplied developer to the developing region RG facing the photoconductor drum 81.

Each of the regulating member 55 and the pre-regulating member 56 regulates the amount of the developer held on the outer peripheral surface of the mag roller 52 and conveyed to the developing region RG.

The distance between the regulating member 55 and the mag roller 52 (maximum value of the distance when the distance is not constant) is value A, and the distance between the pre-regulating member 56 and the mag roller 52 (minimum value of the distance when the distance is not constant). ) Is the value B, and it is preferable that the relationship of 2 × A ≧ B> A is established between the value A and the value B. By making the value B larger than the value A, it is possible to avoid a situation in which an excessive amount of the developer is regulated by the pre-regulating member 56, and a sufficient leveling effect by the regulating member 55 can be obtained. Further, by setting the value B to twice or less the value A, the pre-regulatory member 56 can sufficiently obtain the function of regulating the developer.

Further, the regulating member 55 and the pre-regulating member 56 are provided at a predetermined interval. In this case, the developer that has passed through the pre-regulatory member 56 passes through the regulatory member 55 after passing through a state in which it is not regulated. The regulating member 55 and the pre-regulating member 56 may be in contact with each other at regular intervals. In this case, the developer that has passed through the pre-regulatory member 56 immediately passes through the regulatory member 55.

In the developing region RG, the mag roller 52 supplies the toner in the developer to the electrostatic latent image formed on the surface of the photoconductor drum 81 to develop the electrostatic latent image.

According to the present embodiment, the amount of the developer guided to the developing region RG by the pre-regulating member 56 can be regulated on the upstream side in the rotation direction of the mag roller 52 with respect to the regulating member 55. This is due to the configuration in which the partition wall 60 includes three or more openings 61a, 61b, 61c, 61d, 61e, and 61f (a configuration in which a transport path for branching or merging is formed in the housing 51). The amount of the developer held on the mag roller 52 can be made uniform by suppressing unevenness in the rotation axis R direction.

In order to confirm this effect, the inventors of the present application circulate the developer in each of the developing apparatus 31 of the present embodiment and the developing apparatus of the comparative example, and rotate the axis of the amount of the developer held in the mag roller 52. The distribution in the R direction was examined.

FIG. 4 is a cross-sectional view showing the configuration of the developing apparatus of the comparative example.

With reference to FIG. 4, as a comparative example, the member that regulates the amount of the developer held on the outer peripheral surface of the mag roller 52 and conveyed to the developing region RG does not include the pre-regulating member and does not include the pre-regulating member 55. We assumed a developing device that included only. The configuration of the developing apparatus other than this is the same as the configuration of the developing apparatus 31 of the present embodiment shown in FIG. The distance between the regulating member 55 and the mag roller 52 was set to 0.4 mm.

FIG. 5 is a diagram showing the distribution of the amount of the developer held on the mag roller 52 in the comparative example in the rotation axis R direction. FIG. 5 center line L11 shows the distribution of the amount of the developer before passing through the regulating member 55, and FIG. 5 center line L12 shows the distribution of the amount of the developing agent after passing through the regulating member 55. Is.

With reference to FIG. 5, in the comparative example, the unevenness of the amount of the developer in the rotation axis R direction remained even after passing through the regulating member 55. In this way, in the configuration in which the developer is circulated and transported along the plurality of transport paths, the height difference of the liquid level of the developer in the supply tank becomes large, and the restricting member 55 alone is held by the mag roller 52. It is not possible to make the unevenness of the amount of the developer in the rotation axis R direction uniform.

FIG. 6 is a diagram showing the distribution of the amount of the developer held on the mag roller 52 of the developing apparatus 31 of the first embodiment of the present invention in the rotation axis R direction. FIG. 6 center line L1 shows the distribution of the amount of the developing agent before passing through the regulating member 55 and the pre-regulating member 56, and FIG. 6 center line L2 shows the distribution after passing through the regulating member 55 and the pre-regulating member 56. It shows the distribution of the amount of the developer in.

With reference to FIG. 6, the developing apparatus 31 of the present embodiment includes a regulating member 55 and pre-regulation as members for regulating the amount of the developing agent held on the outer peripheral surface of the mag roller 52 and conveyed to the developing region RG. Includes member 56. The distance between the regulating member 55 and the mag roller 52 was set to 0.4 mm. The distance between the pre-regulatory member 56 and the mag roller 52 was set to 0.7 mm.

In the developing apparatus 31 of the present embodiment, the amount of the developing agent after passing through the regulating member 55 could be uniformly leveled in the rotation axis R direction as compared with the case of the comparative example.

[Second Embodiment]

FIG. 7 is a diagram showing the configuration of the pre-regulatory member 56 according to the second embodiment of the present invention. FIG. 7A is a diagram showing the height of the liquid level of the developer along the rotation axis R direction in the supply tank SP2 when the developer is conveyed. FIG. 7B is a cross-sectional view taken along the line III-III of FIG. FIG. 7C is a diagram showing a first configuration of the pre-regulatory member 56 according to the second embodiment of the present invention. FIG. 7D is a diagram showing a second configuration of the pre-regulatory member 56 according to the second embodiment of the present invention.

When the liquid level of the developer in the supply tank SP2 is observed in detail with reference to FIGS. 7 (a) and 7 (b), the liquid level of the developer along the rotation axis R direction of the supply screw 54 in the supply tank SP2 is , It increases at the position corresponding to each of the openings 61c and 61e which are the intermediate inflow ports, and decreases at the position corresponding to each of the openings 61b and 61d which are the intermediate flow outlets, and the partition wall where the opening does not exist. At the position of 60, it remains high or low and is substantially constant.

As described above, in the configuration having a plurality of transport paths, the openings 61b and 61c are provided with respect to the developer transported along the long annular transport path (the transport path indicated by the solid line arrow in FIG. 7B). , 61d, and 61e, respectively, because the developer branches or merges (the transport path indicated by the arrow in the middle dotted line in FIG. 7B), at positions corresponding to each of the openings 61b, 61c, 61d, and 61e. The height of the liquid level of the developer fluctuates.

Therefore, the shape of the pre-regulatory member 56 of the present embodiment in the rotation axis R direction changes depending on the positions of the openings 61b, 61c, 61d, and 61e. Specifically, at a position in the rotation axis R direction in the supply tank SP2, the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed by the first difference or more. The amount of the developer regulated by the pre-regulatory member 56 is such that the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed in the rotation axis R direction in the supply tank SP2. The amount of the developer regulated by the pre-regulating member 56 is larger than the amount regulated by the pre-regulating member 56 at a position lower than the difference of 2.

With reference to FIGS. 7 (a), 7 (b), and 7 (c), in the first configuration of the pre-regulatory member 56 in the second embodiment, the pre-regulatory member 56 is a rotating shaft R. It includes a plurality of regulatory sections 56a, 56b, and 56c that are spaced (intermittently) from each other along. In each of the plurality of regulating portions 56a, 56b, and 56c, the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed in the rotation axis R direction in the supply tank SP2. It is provided at a position PO1 that is higher than the first difference (hereinafter, may be referred to as a position PO1 where the liquid level of the developer is high). In each of the plurality of regulating portions 56a, 56b, and 56c, the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed in the rotation axis R direction in the supply tank SP2. It is not provided at the position PO2 where the liquid level of the developer is lower than the second difference (hereinafter, it may be referred to as the position PO2 where the liquid level of the developer is low).

With reference to FIGS. 7 (a), 7 (b), and 7 (d), in the second configuration of the pre-regulatory member 56 in the second embodiment, the pre-regulatory member 56 is a rotating shaft R. The distance between the pre-regulatory member 56 and the mag roller 52 corresponds to a change in the height of the liquid level during transfer of the developer in the rotation axis R direction in the supply tank SP2. Is changing. The distance between the pre-regulatory member 56 and the mag roller 52 at the position corresponding to the position PO1 where the liquid level of the developer in the rotation axis R direction is high corresponds to the position corresponding to the position PO2 where the liquid level of the developer in the rotation axis R direction is low. It is narrower than the distance between the pre-regulatory member 56 and the mag roller 52 in the above.

Since the configuration of the image forming apparatus other than the above is the same as the configuration of the image forming apparatus in the first embodiment, the same members are designated by the same reference numerals, and the description thereof will not be repeated.

According to the present embodiment, the shape of the pre-regulatory member 56 in the rotation axis R direction changes according to the positions of the openings 61b, 61c, 61d, and 61e which are the intermediate circulation ports, and the pre-regulatory member 56 and the pre-regulatory member 56 Since the distance from the mag roller 52 changes according to the change in the height of the liquid level during the transfer of the developer in the rotation axis R direction in the supply tank SP2, the amount of the developer held in the mag roller 52. The unevenness in the rotation axis R direction can be effectively suppressed.

[Third Embodiment]

FIG. 8 is a diagram showing the configuration of the pre-regulatory member 56 according to the third embodiment of the present invention. FIG. 8A is a diagram showing the height of the liquid level of the developer along the rotation axis R direction in the supply tank SP2 when the developer is conveyed. FIG. 8B is a cross-sectional view taken along the line III-III of FIG. FIG. 8C is a diagram showing a first configuration of the pre-regulatory member 56 according to the third embodiment of the present invention. FIG. 8D is a diagram showing a second configuration of the pre-regulatory member 56 according to the third embodiment of the present invention.

When the liquid level of the developer in the supply tank SP2 is observed in more detail with reference to FIGS. 8 (a) and 8 (b), the developer along the rotation axis R direction of the supply screw 54 in the supply tank SP2 is observed. The liquid level gradually increases from the upstream side to the downstream side in the developing agent transport direction in the supply tank SP2 indicated by the arrow D2 at the positions corresponding to the openings 61c and 61e, which are the inflow ports on the way. At each of the openings 61b and 61d, which are the outlets on the way, the amount gradually decreases from the upstream side to the downstream side in the transport direction of the developer in the supply tank SP2 indicated by the arrow D2. There is.

Therefore, the shape of the pre-regulatory member 56 of the present embodiment in the rotation axis R direction is adjusted to the fluctuation of the liquid level of the developer at each position of the openings 61b, 61c, 61d, and 61e which are the intermediate circulation ports. Therefore, the distance between the pre-regulatory member 56 and the mag roller 52 is gradually changing.

With reference to FIGS. 8 (a), 8 (b), and 8 (c), in the first configuration of the pre-regulatory member 56 in the third embodiment, the pre-regulatory member 56 is a second. Similar to the first configuration (FIG. 7 (c)) of the pre-regulating member 56 in the embodiment, a plurality of regulating portions 56a, 56b provided at intervals (intermittently) along the rotation axis R. , And 56c are included. Each of the plurality of regulating portions 56b and 56c is indicated by an arrow at a position corresponding to the openings 61c and 61e which are intermediate inlets in the rotation axis R direction (position PO3 where the height of the liquid level of the developer gradually increases). The distance between the pre-regulatory member 56 and the mag roller 52 gradually decreases from the upstream side to the downstream side in the transport direction of the developer in the supply tank SP2 shown by D2. Each of the plurality of regulating portions 56a and 56b is located at a position corresponding to each of the openings 61b and 61d which are intermediate outlets in the rotation axis R direction (position PO4 where the height of the liquid level of the developing agent gradually decreases). , The distance between the pre-regulatory member 56 and the mag roller 52 gradually increases from the upstream side to the downstream side in the transport direction of the developer in the supply tank SP2 indicated by the arrow D2.

With reference to FIGS. 8 (a), 8 (b), and 8 (d), in the second configuration of the pre-regulatory member 56 in the third embodiment, the pre-regulatory member 56 is the second. Similar to the second configuration (FIG. 7 (d)) of the pre-regulatory member 56 in the embodiment, the pre-regulatory member 56 extends continuously along the rotation axis R. At the positions corresponding to the respective positions of the openings 61c and 61e (the position PO3 where the height of the liquid level of the developing agent gradually increases), which are the inflow ports on the way, the developing agent in the supply tank SP2 indicated by the arrow D2. The distance between the pre-regulatory member 56 and the mag roller 52 gradually decreases (for example, from 0.9 mm to 0.7 mm) from the upstream side to the downstream side in the transport direction. Each of the plurality of restricting portions 56a and 56b has an arrow D2 at a position corresponding to each position of the openings 61b and 61d which are intermediate outlets (position PO4 where the height of the liquid level of the developer gradually decreases). The distance between the pre-regulatory member 56 and the mag roller 52 gradually increases (for example, from 0.7 mm to 0.9 mm) from the upstream side to the downstream side in the transport direction of the developer in the supply tank SP2 shown by. There is.

The height of the liquid level of the developer at the position corresponding to each of the openings 61b, 61c, 61d, and 61e is lower than the height of the liquid level of the developer at the position corresponding to the partition wall 60. .. In order to adjust the regulatory force of the pre-regulatory member 56 according to the height of the liquid level of the developer, the pre-regulatory member 56 and the mag roller 52 at positions corresponding to each of the openings 61b, 61c, 61d, and 61e The distance between the two is preferably larger than the distance between the pre-regulatory member 56 and the mag roller 52 at the position corresponding to the partition wall 60.

In particular, the distance between the pre-regulatory member 56 and the mag roller 52 at the position corresponding to the partition wall 60 in the rotation axis R direction (the maximum value of the distance when the distance is not constant) is set to a value C, and the opening in the rotation axis R direction. When the distance between the pre-regulatory member 56 and the mag roller 52 at the positions corresponding to 61b, 61c, 61d, and 61e (the minimum value of the distance when the distance is not constant) is set to the value D, the value C and the value D It is preferable that the relationship of 1.5 × C ≧ D> C is established between them. As a result, unevenness in the amount of the developer held on the mag roller 52 in the rotation axis R direction can be effectively suppressed.

Since the configuration of the image forming apparatus other than the above is the same as the configuration of the image forming apparatus in the first and second embodiments, the same members are designated by the same reference numerals and the description thereof will not be repeated. ..

According to the present embodiment, the distance between the pre-regulatory member 56 and the mag roller 52 is reduced along the transport direction of the developer at the positions corresponding to the openings 61c and 61e, which are the inlets in the middle. , The number increases along the transport direction of the developer at the positions corresponding to the openings 61b and 61d, which are the midway outlets. As a result, the distance between the pre-regulatory member 56 and the mag roller 52 corresponds to the height of the liquid level of the developer at the positions corresponding to each of the intermediate inflow port and the intermediate inflow port, and is held by the mag roller 52. The unevenness of the amount of the developing agent in the rotation axis R direction can be further suppressed.

[Fourth Embodiment]

FIG. 9 is a diagram showing the configuration of the pre-regulatory member 56 according to the fourth embodiment of the present invention. FIG. 9A is a diagram showing the height of the liquid level of the developer in the rotation axis R direction in the supply tank SP2. FIG. 9B is a diagram showing a first configuration of the pre-regulatory member 56 according to the fourth embodiment of the present invention. FIG. 9C is a diagram showing a second configuration of the pre-regulatory member 56 according to the fourth embodiment of the present invention.

With reference to FIG. 9, due to the configuration of the developing apparatus 31, the developing agent tends to be biased toward one of the openings 61a and 61f at both ends of the mag roller 52 in the rotation axis R direction. In some cases, the liquid level of the developer inside is inclined in the R direction of the rotation axis. As an example, in a configuration in which the supply screw 54 is provided above the stirring screw 53 in order to reduce the width of the developing device 31 in the rotation axis R direction, one end side (here, an opening) in the rotation axis R direction is provided. A pumping portion for pumping the developing agent from the stirring tank SP1 to the supply tank SP2 is provided on the portion 61a side), and the stirring tank from the supply tank SP2 is provided on the other end side (here, the opening 61f side) in the rotation axis R direction. The SP1 is provided with a pumping section for pumping the developer. In the supply tank SP2 near the pumping portion, the developer tends to accumulate, and the liquid level of the developer rises. In the supply tank SP2 near the pumping portion, the developer tends to be deficient, and the liquid level of the developer becomes low. As a result, as shown by line E, the height of the liquid level of the developer in the supply tank SP2 is roughly seen, and the liquid level of the developer in the supply tank SP2 is from the opening 61a side to the opening 61f side. Decreases toward. As another example, the same phenomenon occurs when the developing device 31 (rotation axis R) is arranged at an angle with respect to the horizontal plane.

In the present embodiment, the size of the distance between the pre-regulatory member 56 and the mag roller 52 changes according to the inclination of the liquid level of the developer in the supply tank SP2 as described above. Specifically, as the liquid level of the developer in the supply tank SP2 rises (as it approaches the left end in FIG. 9), the distance between the pre-regulatory member 56 and the mag roller 52 becomes narrower. 9 (b) shows a configuration in which the pre-regulatory member 56 includes a plurality of regulatory portions 56a, 56b, and 56c, and FIG. 9 (c) shows the pre-regulatory member 56 extending continuously along the rotation axis R. It is an existing configuration.

Since the configuration of the image forming apparatus other than the above is the same as the configuration of the image forming apparatus in the third embodiment, the same members are designated by the same reference numerals, and the description thereof will not be repeated.

According to the present embodiment, since the distance between the pre-regulatory member 56 and the mag roller 52 changes according to the inclination of the liquid level of the developer in the supply tank SP2, the development held by the mag roller 52 The unevenness of the amount of the agent in the rotation axis R direction of the mag roller 52 can be further suppressed.

[Fifth Embodiment]

FIG. 10 is a cross-sectional view showing the configuration of the developing apparatus 31 according to the fifth embodiment of the present invention.

With reference to FIG. 10, in the developing apparatus 31 of the present embodiment, the diameter of the shaft 71 of the supply screw 54 changes at a position corresponding to the intermediate circulation port in the rotation axis R direction. Specifically, the diameter of the shaft 71 of the supply screw 54 is at a position corresponding to each of the openings 61b and 61d which are intermediate outlets (position PO4 where the height of the liquid level of the developing agent gradually decreases). The partition wall 60 between the opening 61b and the opening 61c and the partition wall 60 between the opening 61d and the opening 61e are increased from the original size to a predetermined size (for example, from 6 mm to 10 mm). The size remains constant at the position corresponding to each (position PO2 where the liquid level of the developer is low), and the position corresponding to each of the openings 61c and 61e which are the inlets in the middle (the height of the liquid level of the developer). At the position PO3) where is gradually increasing, it is reduced from a predetermined size to the original size (for example, from 10 mm to 6 mm).

Instead of changing the diameter of the shaft 71 at the position corresponding to the intermediate circulation port in the rotation axis direction as described above (or the diameter of the shaft 71 changes at the position corresponding to the intermediate circulation port in the rotation axis direction). In addition, the size of the cross-sectional area of the cross section of the supply tank SP2 orthogonal to the rotation axis R may change at a position corresponding to the intermediate circulation port in the rotation axis direction. When reducing the cross-sectional area of the supply tank SP2, a member (gap filling member) for filling the internal space of the housing 51 may be provided in the housing 51.

Since the configuration of the image forming apparatus other than the above is the same as the configuration of the image forming apparatus in the first embodiment, the same members are designated by the same reference numerals, and the description thereof will not be repeated.

According to the present embodiment, at a position where the liquid level of the developer in the supply tank SP2 is low, the cross-sectional area of the cross section orthogonal to the rotation axis R direction of the supply screw 54 decreases, so that the developer in the supply tank SP2 The liquid level of the developing tank can be raised at a position where the liquid level of the developing tank is low, and the liquid level of the developing agent in the supply tank SP2 can be made uniform. Further, since the cross-sectional area of the cross section orthogonal to the rotation axis R direction of the supply screw 54 changes according to the position corresponding to the opening, it is possible to compensate for the change in the supply property due to the change in the liquid level of the developer. As a result, when used together with the above-mentioned pre-regulatory member 56, unevenness in the amount of the developer held on the mag roller 52 in the rotation axis R direction of the mag roller 52 can be further suppressed.

[Sixth Embodiment]

FIG. 11 is a cross-sectional view showing the configuration of the developing apparatus 31 according to the sixth embodiment of the present invention.

With reference to FIG. 11, in the developing apparatus 31 of the present embodiment, the supply screw 54 further includes a supply paddle 74. The supply paddle 74 is provided at a position corresponding to an intermediate circulation port in the rotation axis R direction on the outer peripheral surface of the shaft 71 of the supply screw 54. Specifically, the supply paddle 74 is provided at each of a position corresponding to the position from the opening 61b to the opening 61c and a position corresponding to the position from the opening 61d to the opening 61e.

The height of the supply paddle 74 along the radial direction of the shaft 71 is at a position corresponding to each of the openings 61b and 61d which are intermediate outlets (position PO4 where the height of the liquid level of the developer gradually decreases). , Increasing from zero to a predetermined height (for example, to a height comparable to the outer diameter of the blade member 72), the partition wall 60 between the opening 61b and the opening 61c, and the opening 61d and the opening 61e. At the position corresponding to each of the partition walls 60 between them (position PO2 where the liquid level of the developing agent is low), the height remains constant at a predetermined height, and the positions corresponding to each of the openings 61c and 61e which are the inlets in the middle (development). At the position PO3) where the height of the liquid level of the agent gradually increases, it decreases from a predetermined height to zero.

The supply paddle 74 extends along the shaft 71 of the supply screw 54, and the thickness of the supply screw 54 along the circumferential direction of the shaft 71 is, for example, 1 mm. Although only one supply paddle 74 is provided along the circumferential direction of the supply screw 54, the number of supply paddles 74 may be plural.

Instead of providing the supply paddle 74 at a position corresponding to the intermediate circulation port on the outer peripheral surface of the shaft 71 of the supply screw 54 as described above (or the supply paddle 74 corresponds to the intermediate circulation port on the outer peripheral surface of the shaft 71 of the supply screw 54). The number of blade members 72 of the supply screw 54 is different between the position corresponding to the intermediate circulation port in the rotation axis R direction and the position not corresponding to the intermediate circulation port in the rotation axis R direction. It may be.

Since the configuration of the image forming apparatus other than the above is the same as the configuration of the image forming apparatus in the first embodiment, the same members are designated by the same reference numerals, and the description thereof will not be repeated.

According to the present embodiment, by providing the supply screw 54, even if the height of the liquid level of the developer in the supply tank SP2 is low, the developer can be scooped up to supply power to the mag roller 52. Can be enhanced. Further, since the height of the supply paddle 74 changes according to the position corresponding to the opening, it is possible to compensate for the change in supplyability due to the change in the liquid level of the developer. As a result, when used together with the above-mentioned pre-regulatory member 56, unevenness in the amount of the developer held on the mag roller 52 in the rotation axis R direction of the mag roller 52 can be further suppressed.

[others]

The above-described embodiments can be combined as appropriate. For example, the diameter of the shaft 71 of the supply screw 54 of the fifth embodiment is changed at a position corresponding to the intermediate circulation port in the rotation axis R direction, or the supply paddle 74 of the sixth embodiment is the supply screw. The configuration provided at the position corresponding to the intermediate circulation port in the rotation axis R direction on the outer peripheral surface of the shaft 71 of 54 can be applied to any of the configurations of the first to fourth embodiments. ..

The embodiments described above should be considered exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10 Paper transport unit 11 Paper feed tray 13a Paper feed roller 13b Transport roller 13c Paper discharge roller 14 Paper discharge tray 30 Toner image forming unit 31, 31a, 31b, 31c, 31d Developer 32, 32a, 32b, 32c, 32d Photoconductor Unit 33 Exposure device 34 Intermediate transfer belt 35a, 35b, 35c, 35d Primary transfer roller 36 Secondary transfer roller (example of transfer means)
37 Cleaning device 39 Rotating roller 40 Fixing device 41 Heating roller 42 Pressurizing roller 51 Housing 51a Housing discharge port 52 Mag roller (example of developer holding member)
52a Rotating sleeve 52b Magnet member 53 Stirring screw (Example of transport means)
54 Supply screw (an example of transport means)
55 Regulatory member (an example of the first regulatory member)
56 Pre-regulatory member (an example of the second regulatory member)
56a, 56b, 56c Control part 60 Partition wall 61a, 61b, 61b, 61c, 61d, 61e, 61f Opening 71 Shaft 72 Blade member 73 Paddle 74 Supply paddle 81 Photoreceptor drum (example of image carrier)
82 Charging device 83 Cleaning device 100 Image forming device 100a Image forming device body P Paper R Mag roller rotation axis RG Development area SP1 Stirring tank (example of first storage chamber)
SP2 supply tank (an example of the second containment chamber)
TR transport route

Claims (12)

A developing device that develops an electrostatic latent image formed on an image carrier.
A housing that houses the developer and
A partition wall that divides the housing into a first accommodation chamber and a second accommodation chamber, and includes a partition wall including three or more openings.
A transport means for circulating and transporting the developer along a plurality of transport paths formed by the three or more openings inside the first and second storage chambers.
A developer holding member that rotates around a rotation axis, which acquires a developer from the inside of the second storage chamber, holds the acquired developer on the outer peripheral surface, and forms a developing region facing the image carrier. Leading developer holding member and
A first regulating member that regulates the amount of the developer guided to the developing region by the developer holding member, and
A second regulating member that regulates the amount of the developing agent guided to the developing region by the developing agent holding member is provided on the upstream side of the developing agent holding member in the rotational direction with respect to the first regulating member .
The three or more openings are arranged along the transport direction of the developer inside the second storage chamber.
The three or more openings
An end inlet, which is provided on one end side of the partition wall in the direction of the rotation axis and is an inlet of the developer from the first accommodating chamber to the second accommodating chamber.
An end outlet, which is provided on the other end side of the partition wall in the direction of the rotation axis and is an outlet of the developer from the second accommodation chamber to the first accommodation chamber.
Including an intermediate circulation port provided between the end inlet and the end outlet in the partition wall.
The intermediate circulation port is
Among the three or more openings arranged, the first intermediate circulation which is an opening adjacent to the end inflow port on the upstream side in the developing agent transport direction inside the second storage chamber. Mouth and
Among the three or more openings arranged, the second opening which is adjacent to the first intermediate circulation port on the upstream side in the transport direction of the developer inside the second storage chamber. Including the circulation port on the way
The amount of the developer regulated by the second regulating member at a position corresponding to the portion of the partition wall sandwiched between the end inlet and the first intermediate circulation port is the amount of the developing agent regulated by the first intermediate circulation port. A developing apparatus having a position corresponding to a portion of the partition wall sandwiched between the second intermediate circulation port and the second intermediate circulation port, which is larger than the amount of the developing agent regulated by the second regulating member. A developing device that develops an electrostatic latent image formed on an image carrier.
A housing that houses the developer and
A partition wall that divides the housing into a first accommodation chamber and a second accommodation chamber, and includes a partition wall including three or more openings.
A transport means for circulating and transporting the developer along a plurality of transport paths formed by the three or more openings inside the first and second storage chambers.
A developer holding member that rotates around a rotation axis, which acquires a developer from the inside of the second storage chamber, holds the acquired developer on the outer peripheral surface, and forms a developing region facing the image carrier. Leading developer holding member and
A first regulating member that regulates the amount of the developer guided to the developing region by the developer holding member, and
A second regulating member that regulates the amount of the developing agent guided to the developing region by the developing agent holding member is provided on the upstream side of the developing agent holding member in the rotational direction with respect to the first regulating member.
The three or more openings
An end inlet, which is provided on one end side of the partition wall in the direction of the rotation axis and is an inlet of the developer from the first accommodating chamber to the second accommodating chamber.
An end outlet, which is provided on the other end side of the partition wall in the direction of the rotation axis and is an outlet of the developer from the second accommodation chamber to the first accommodation chamber.
Including an intermediate circulation port provided between the end inlet and the end outlet in the partition wall.
The shape of the second regulating member in the direction of the rotation axis changes at a position corresponding to the intermediate circulation port.
In the direction of the rotation axis in the second storage chamber, the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed by the first difference or more. The amount of the developing agent regulated by the restricting member of the above is such that the height of the liquid level when the developing agent is conveyed is higher than the height of the liquid level when the developing agent is not conveyed in the direction of the rotation axis in the second accommodating chamber. greater than the amount of the developer in which the second regulating member is regulated by the second difference or lower position, the current image device. The second regulating member includes a plurality of regulating portions provided at intervals in the rotation axis direction.
In each of the plurality of regulating portions, the height of the liquid level when the developer is conveyed is higher than the height of the liquid level when the developer is not conveyed in the direction of the rotation axis in the second accommodating chamber. The developing apparatus according to claim 2 , which is provided at a position higher than the difference between the two. The second regulating member extends continuously in the direction of the rotation axis.
A claim that the distance between the second regulating member and the developer holding member changes according to a change in the height of the liquid level during transportation of the developer in the direction of the rotation axis in the second accommodating chamber. 2. The developing apparatus according to 2. The intermediate circulation port includes an intermediate inlet which is an inlet of the developer from the first accommodation chamber to the second accommodation chamber.
Any of claims 2 to 4 , wherein the distance between the second regulating member and the developer holding member decreases along the developer transport direction at a position corresponding to the intermediate inflow port in the rotation axis direction. The developing apparatus according to. The intermediate circulation port includes an intermediate outlet which is an outlet of the developer from the second accommodation chamber to the first accommodation chamber.
Any of claims 2 to 5 , wherein the distance between the second regulating member and the developer holding member increases along the developer transport direction at a position corresponding to the intermediate outlet in the rotation axis direction. The developing apparatus according to. The transport means
A shaft that extends and rotates in the direction of the rotation axis,
Including a blade member spirally provided on the outer peripheral surface of the shaft.
At least one of the diameter of the shaft and the size of the cross-sectional area of the cross section orthogonal to the rotation axis of the second storage chamber changes at a position corresponding to the intermediate circulation port in the rotation axis direction. The developing apparatus according to any one of claims 2 to 6. The developing apparatus according to claim 7 , wherein the transport means further includes a paddle provided at a position corresponding to the intermediate circulation port in the rotation axis direction on the outer peripheral surface of the shaft in the second accommodation chamber. The claim that the number of rows of the blade member in the second accommodating chamber is different between a position corresponding to the intermediate circulation port in the rotation axis direction and a position not corresponding to the intermediate circulation port in the rotation axis direction. 7. The developing apparatus according to 7. The maximum value of the distance between the second regulating member and the developer holding member at the position corresponding to the partition wall in the rotation axis direction is a value C, and the position corresponding to the intermediate circulation port in the rotation axis direction. When the minimum value of the distance between the second regulating member and the developer holding member is set to the value D, the relationship of 1.5 × C ≧ D> C holds between the value C and the value D. , The developing apparatus according to any one of claims 2 to 9. The value when the maximum value of the distance between the first regulating member and the developer holding member is a value A and the maximum value of the distance between the second regulating member and the developing agent holding member is a value B. The developing apparatus according to any one of claims 1 to 10 , wherein a relationship of 2 × A ≧ B> A holds between A and the value B. The developing apparatus according to any one of claims 1 to 11.
An image forming apparatus including a transfer means for transferring an electrostatic latent image developed by the developing apparatus onto paper.

Images