JPH1152727A - Developer carrying member and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stir suspending toner suspending on the upper surface of developer newly supplied and housed inside a developing container even in a condition where the amount of the developer inside the developing container is comparatively large. SOLUTION: This developing device is provided with the developing container 41 housing a developing roll R0, carrying members R1 and R2, and the developer, a rotating shaft 56 rotating when the members R1 and R2 extend in the carrying direction of the developer, a spiral rotary wing 57 fixed to the shaft 56 and rotating, and plural projecting members 58 projecting on the upstream side of the carrying direction from the outer peripheral part of the wing 57, formed shorter than the pitch of the wing 57 and arranged at a specified interval around the shaft; and the members 58 of the members R1 and R2 move the developer around the shaft, stir and carry the developer adjacent to the upper end side and upstream side of the outer peripheral part of the wing 57 with the developer below the outer peripheral part upper end side of the wing 57, and supply it to the roll R0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image formed on an image carrier into a toner image in an image forming apparatus such as an electrophotographic copying machine or a laser printer. The present invention relates to a developer conveying member that rotates around and conveys a developer while stirring it around an axis, and a developing device including the developer conveying member.

[0002]

2. Description of the Related Art In recent years, with the spread of facsimile machines and personal computers, opportunities for outputting digital images have been remarkably widespread. The demand for digital image output has also increased for image forming apparatuses of the electrophotographic type, and digitization in which a digital-compatible exposure apparatus is mounted on a conventional analog image forming apparatus is progressing. In such an environment, users who create documents are increasingly demanding an output image with a good image quality, that is, an output image that faithfully reproduces even minute pixels.

A conventional electrophotographic image forming apparatus employs a developing method using a two-component developer composed of a toner and a magnetic carrier. When image formation is performed continuously in this manner, the toner supplied into the developing container of the developing device is helically wrapped around the rotating shaft and the rotating shaft in the developer stirring area in the developing container and fixed. After being mixed and agitated with the magnetic carrier by a developer conveying member composed of the formed spiral rotor, the magnetic carrier is supplied to a developing roll accommodated in a developing roll accommodating portion adjacent to the developer agitating region. The developing roll transports the toner to a developing area on the image carrier where the electrostatic latent image is developed, and develops the electrostatic latent image. Incidentally, in order to faithfully reproduce the minute pixels, it is effective to make the toner fine. Further, when the toner is made finer, the ratio of covering the surface of the carrier increases even with the same weight of toner. Therefore, when the particle size of the carrier is the same, if the particle size of the toner is small,
Since the entire surface of the carrier is covered with a small amount of toner, the amount of toner attached to the carrier and conveyed to the developing area is reduced. For this reason, in order to hold a sufficient amount of toner in the developer, it is necessary to make the carrier fine at the same time.

However, in the case of a developer in which the toner and the carrier are made fine, powder fluidity deteriorates, and the replenished toner is stored in the developing container when being stirred and transported by the developer transporting member. The floating toner which is not taken into the developer while floating on the upper surface of the developer is generated, and the floating toner is conveyed to the developing roll in a state where it is not sufficiently charged in contact with the carrier. For this reason, when the electrostatic latent image on the image carrier is developed, the background is smeared (that is, when the charge of the developer decreases, toner charged to the opposite polarity is generated, and the non-image on the image carrier is developed at the time of development. (A phenomenon that toner adheres to a portion). In a developing device for a two-component developer having a pair of developer conveying members composed of the rotating shaft and the helical rotating blade, the following technology (J01) has been used to sufficiently charge the replenished toner with the carrier. ) To (J04) are known.

(J01) (Technique described in JP-A-56-70576) The technique described in this publication is composed of a rotating cylindrical member and a helical rotating blade fixed to the inner peripheral surface of the rotating cylindrical member. A pair of developer conveying members are arranged in the developing container.
The developer supplied into the developing container is agitated and transported inside the rotating cylindrical member. (J02) (Technology described in Japanese Patent Application Laid-Open No. 62-288873) The technique described in this publication is such that a regulating member is brought into contact with the upper end of a spiral rotating blade (developer conveying member) disposed in a developing container,
When the developer is agitated and transported by the developer transport member, the movement of the floating toner that floats on the upper surface of the developer contained in the developing container and does not sufficiently contact and charge the carrier is regulated. This prevents the toner from being transported to the developing roll without being sufficiently contact-charged with the carrier.

(J03) (Technique described in JP-A-4-254879) FIG. 7 is an explanatory view of a developer conveying member described in JP-A-4-254879, and FIG. 7A is a view of the developer conveying member. FIG. 7B is a partially enlarged explanatory view, FIG. 7B is a sectional view taken along the line VIIB-VIIB of FIG. 7A, and FIG. 7C is an explanatory view showing a state of the developer conveying member in a developing container containing a normal amount of developer.
D is an explanatory diagram showing a state of the developer conveying member in a developing container in which a large amount of developer is stored. The developer conveying member 01 shown in FIG. 7 includes a rotating shaft 02 and a helical rotating blade 03 fixed to the outer periphery of the rotating shaft 02, and a rotating shaft between the rotating blades 03 in the axial direction. On the outer peripheral surface 02, a plate-like stirring blade 04 extending in the diameter direction and having a plane parallel to the developer transport direction Y (the arrow Y direction shown in FIG. 7A) is arranged. As shown in FIG. 7C, when the amount of the developer is normal, the rotation of the rotating shaft 02 also rotates the plate-like stirring blade 04 around the axis, and the floating toner 07 on the upper surface of the developer 06 is caught by the plate-like stirring blade 04. To move around the axis, and is stirred with the developer 06 in the container.
Further, when a large amount of developer is stored in the container as shown in FIG. 7D, a depression 06a of the developer is formed on the upper surface of the developer 06 after the spiral rotary blade 03 has passed. . The floating toner 07 is formed in the developer cavity 06a.
, And are rolled into the developer 06 by the plate-like stirring blade 04 and mixed.

(J04) (Technique described in JP-A-9-26694) FIG. 8 is an explanatory view of a developer conveying member described in JP-A-9-26694, and FIG. 8A is a view of the developer conveying member. FIG. 8B is a sectional view taken along line VIIIB-VIIIB of FIG. 8A, and FIG. 8C is a view showing a state of the developer conveying member in a developing container containing the developer. FIG.
7, the same components as those in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and detailed description thereof will be omitted. In FIG. 8, an elastic member 08 formed of a coil spring or the like is arranged at several positions on the spiral rotary wing 03 in parallel with the rotary shaft 02. In FIG. 8C, when the developer 06 is agitated, the conveying force of the developer 06 is weakened at the position where the elastic member 08 is disposed, so that a bulging portion 06b of the developer 06 is formed. When the bulging portion 06b becomes a certain size, it collapses, and the collapsed developer and the toner 07 to be conveyed in a floating state are mixed and stirred.

[0008]

[Problems to be solved by the invention]

(Problem of (J01)) The developer transport member of the prior art (J01) has a problem that it is difficult to adopt in an actual apparatus because the structure is complicated and expensive. (Problem of (J02)) In the conventional technology (J02),
When a soft toner (toner having a small molecular weight) is used, an aggregate of the developer is formed at a portion where the upper end of the helical rotary blade and the regulating member come into contact with each other in the developer transport path, and a point-like stain is generated on an image. There is a problem of doing.
For this reason, there is a problem that it is not preferable for the relatively soft toner used by the present inventors.

(Problem of (J03)) According to the prior art (J03), the method of manufacturing the developer conveying member 01 is simple and has few defects. However, when the amount of the developer contained in the developing container (the amount of the developer, that is, the height of the developer in the developing container) becomes higher than the height of the upper end of the developer conveying member 01, the following problem occurs. That is, the bulk of the developer is affected by the toner density of the developer, and when the toner density is low, the bulk decreases and when the toner density is high, the bulk increases. The toner density depends on the humidity environment near the image forming apparatus. The reason is as follows. In general, when the humidity environment of the developer changes, the charge amount of the toner changes. In the case of low humidity, the charge amount of the toner increases. In an electrophotographic image forming apparatus, when the charge amount of the toner is high, the potential of the developed toner image on the image carrier balances with the bias voltage in a state where a small amount of toner adheres to the image carrier. The amount of toner for forming an image decreases, that is, the density of the developed toner image decreases.

When the humidity becomes high, the charge amount of the toner becomes low. When the charge amount of the toner is low, the potential of the developed toner image on the image carrier balances with the bias voltage in a state where a large amount of toner adheres to the image carrier, so that the amount of toner for forming an image increases. That is, the density of the developed toner image increases. In the image forming apparatus studied by the present inventor, the amount of toner (toner image density) for forming an image on the image carrier is controlled within a certain range regardless of the humidity environment. Since the toner is replenished so as to increase the density and the developer is discharged such that the toner density in the developing container decreases when the humidity is high, the amount of the developer changes depending on the humidity environment.

Therefore, since the amount of developer changes depending on the humidity environment near the image forming apparatus, the amount of developer 06 increases as shown in FIG. 7D due to the change in the humidity environment around the image forming apparatus. When the upper surface of the developer 06 reaches the upper end of the spiral rotary blade 02 and the plate-like stirring member 04, the resistance of the developer 06 increases, and the conveying force of the developer 06 by the plate-like stirring member 04 increases. As a result, the developer bulge 06b is formed. For this reason, the upper end side of the outer peripheral portion of the plate-shaped stirring member 04 is buried in the bulge 06b of the developer, and the floating toner 07
Is raised by the bulge 06b of the developer and cannot be rolled into the developer 06.

(Problem of (J04)) In the prior art (J04), the position where the cover (upper lid) C of the developing container (see a two-dot chain line in FIG. 8C) is close to above the developer conveying member 01 is described. In the small developing container, the developer 06 rises from the upper surface of the developer 06 accommodated in the developing container and rises from the upper surface of the developer 06 (see FIG. 8C). The side surface is rubbed, causing a change in the surface of the toner and the carrier. As a result, there is a problem that the chargeability and the transfer efficiency of the developer 06 significantly change. When the consumption of toner is large, it is necessary that the time from the supply of the toner to the development area is short and the charge amount of the toner is sufficient. However, in the conventional technique (J04), the toner supplied is There is also a problem that the time for transport to the developing roll is delayed while the inner surface of the cover of the developing container is rubbed.

The present inventor conducted the following experiment to obtain a more effective developer conveying member. A developer in a conventional developing device includes a ferrite carrier having a volume center diameter of 50 × 10 ⁻⁶ (m) and a density of about 3.5 × 10 ⁶ (g / m ³ ), and a volume center containing styrene acrylic as a main component. 9.5 × 1 diameter
0 ^-6 (m), stirred and mixed toner density of about ^{1.1 × 10 6 (g / m} 3), the toner in the image forming apparatus 20 ([mu] C
/ G) that was adjusted to be used with the charge amount before and after. The present inventor has reported that the volume center diameter is 35 × 10 ^−6.
(M), a ferrite core with a density of about 3.5 × 10 ⁶ (g / m ³ ) coated on a ferrite core (material: fluorine resin, thickness: 2 μm)
Created a career. 6.5x with the carrier
A conventional developing device using a two-component developer (small-diameter developer) in combination with a toner having a diameter of 10 ^-6 (m), that is, a developing device having a developer conveying member that does not include a member for incorporating floating toner. When trying to faithfully reproduce the minute pixels, the powder flow deteriorated, and the replenished toner was not taken into the developer when transported by the developer transport member, and was not sufficiently contact-charged with the carrier. The developer was transported to the developing roll as it was, causing a problem of causing background contamination during development of the electrostatic latent image.

FIG. 9 is an explanatory view of a developer conveying member prepared for an experiment, FIG. 9A is an enlarged explanatory view of a main part of the developer conveying member, and FIG. 9B is a sectional view taken along line IXB-IXB of FIG. 9A. is there. In FIG. 9, the same components as those in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and detailed description thereof will be omitted. In FIG. 9, the outer periphery of the rotary blade of the spiral rotary blade 02 is connected by a plate-shaped or rod-shaped stirring member 09. If the small-diameter developer 06 has little bulk, the stirring member 09 jumps up the floating toner, so that the replenishment toner is not carried to the developing roll while floating on the upper surface of the developer 06. However, the rotation axis 02
Since the force for moving the developer 06 in the rotation direction is too strong, the force in the transport direction is weaker than the force for moving the developer 06 in the rotation direction. Therefore, there has been a problem that the conveying force of the entire developer (the moving speed of the developer in the longitudinal direction of the developing device (that is, the conveying direction of the developer)) as well as the replenishment toner deteriorates. When the small-diameter developer used by the present inventor is transported, the bulk of the developer 06 (the upper surface of the developer 06) exceeds the height of the upper end of the rotating shaft 02 due to poor fluidity of the small-diameter developer. Since the stirring member 09 does not splash up the developer 06 and the floating toner from around, there is a problem that the intended effect of sufficiently stirring the floating toner with the developer 06 cannot be obtained.

In view of the above circumstances, the present invention provides the following (O01)
Is the subject of the description. (O01) Even when the developer amount in the developing container is relatively large,
The newly-supplied floating toner floating on the upper surface of the developer stored in the developing container and the stored developer can be stirred.

[0016]

Next, a description will be given of the present invention which has solved the above-mentioned problems. In the description of the present invention, reference numerals in parentheses added after constituent elements of the present invention denote constituent elements of the present invention. Reference numerals of corresponding components of the embodiment described later. The reason why the present invention is described in correspondence with the reference numerals of the components of the embodiments described later is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(1st invention) In order to solve the aforementioned problem,
The developer transport member of the first invention of the present application has the following requirements: (A01) a rotating shaft (56) that extends in the developer transport direction and rotates around an axis in the transport direction. A spiral rotating blade (57) fixed to the outer periphery of the rotating shaft (56) and rotating around the axis; and a spiral rotating blade (5).
7) projecting from the outer peripheral portion to the upstream side in the transport direction, and moving the developer around the axis with the rotation of the helical rotary blade (57) to thereby move the developer around the axis to form an upper end of the outer peripheral portion of the helical rotary blade (57) Conveying member (R1 + R2) having a plurality of projecting members (58) for mixing the developer adjacent to the upstream side and the upstream side with the developer below from the upper end side of the outer peripheral portion of the spiral rotor (57); A02) The protruding member (58) in which the protruding length of the protruding member (58) is formed shorter than the pitch of the helical rotor (57) and the interval around the axis is arranged to be constant. The protruding member (58) can be changed to various shapes such as a rod-shaped member, a hollow cylindrical member, and a plate-shaped member.

(Operation of the First Invention) In the developer transport member of the first invention of the present application having the above-described features, the rotating shaft (56) of the transport member (R1 + R2) extending in the developer transport direction is moved in the transport direction. , The helical rotating blade (57) fixed to the outer periphery of the rotating shaft (56) rotates around the axis. When the helical rotor (57) rotates, a plurality of projecting members (58) projecting from the outer peripheral portion of the helical rotor (57) to the upstream side in the transport direction are formed on the helical rotor (57). The developer is moved around the axis along with the rotation so that the developer adjacent to the upper end side of the outer peripheral portion of the spiral rotating blade (57) and the upstream side is accommodated in the developing container (41). The developer is mixed with the developer from the upper end side of the outer peripheral portion of the rotary blade (57).

Therefore, when the developer transport member (R1 + R2) according to the first invention of the present application is used, the spiral rotor (5
The floating toner (69) floating on the upper surface of the developer at a position adjacent to the outer peripheral portion of the helical rotor (57) by the projecting member (58) of the outer peripheral portion of (7), and the developer (68) contained in the developer. ) Is stirred. Further, the projecting length of the projecting member (58) of the conveying member (R1 + R2) is shorter than the pitch of the helical rotating blade (57), so that even if the projecting member (58) rotates around the axis, the resistance to the developer is reduced. And a large amount of developer does not require a large force for rotation around the axis. Therefore, the rotational force of the conveying member (R1 + R2) does not decrease, and the force of the conveying member (R1 + R2) for conveying the developer does not decrease. Therefore, the swelling of the developer (68
a) is not formed, and the floating toner (69) on the upper surface of the developer can be entrained even in a state where the amount of the developer is relatively large, so that the floating toner (69) is transferred to the spiral rotor (57). Can be mixed and transported from the upper end of the outer peripheral portion with the developer below. Further, since the swelling (68a) of the developer is not formed, the swelling (68a) of the developer does not contact the upper wall of the developer conveyance path. Therefore, the present invention can also be used in a small-sized developer conveyance path in which the upper wall of the developer conveyance path is close to the upper side of the conveyance member (R1 + R2).

(Second invention) In order to solve the above problems,
The developing device of the second invention of the present application has the following requirements: (B01) a developing roll (R0) for transporting a developer to a developing area (Q2); and (B02) the developing roll ( R0), and a developing roll (R) adjacent to the developing roll housing (42).
0), a first developer stirring area (43) extending in the axial direction, and a first developer stirring area (43) which is disposed on the opposite side to the developing roll (R0) adjacent to the first developer stirring area (43). The removed portion is partitioned from the first developer stirring area (43) by a partition wall (45), and both ends in the axial direction are connected to the first developer stirring area (43) and are separated from the partition wall (45). Developing containers (41), (B03) having a second developer stirring region (44) formed between the container outer wall extending along the partition wall (45) and containing the developer;
A first transport member (R1) disposed in the first developer stirring area (43) and agitating while transporting the developer in the axial direction of the developing roll; (B04) disposed in the second developer stirring area (44); Then, the second transport member (R2), which stirs the developer while transporting the developer in the opposite direction to the first transport member (R1), (B0
5) a rotary shaft (56) extending in the transport direction of the developer and rotating around an axis in the transport direction; and a spiral rotary wing (5) fixed to the outer periphery of the rotary shaft (56) and rotating around the axis.
7) and projecting from the outer peripheral portion of the spiral rotary blade (57) in the upstream direction in the transport direction to form the spiral rotary blade (5).
7) The developer is moved around the axis with the rotation of the spiral rotating blade (57), and the developer adjacent to the upper end side of the spiral rotating blade (57) and on the upstream side is moved to the outer periphery of the spiral rotating blade (57). The first transport member (R1) and the second transport members (R2), (B06) having a plurality of projecting members (58) to be mixed with the developer from the upper end side of the projecting member (58); The protruding member (58), the length of which is shorter than the pitch of the spiral rotor (57), and the interval around the axis is arranged to be constant. The projecting member (5)
8) can be changed to various shapes such as a rod-shaped member, a hollow cylindrical member, and a plate-shaped member.

(Operation of the Second Invention) In the developing device according to the second invention of the present application having the above-mentioned features, the developing container (41) is provided with the developing roll accommodating portion (4) for accommodating the developing roll (R0).
2) a first developer stirring area (4) that extends in the axial direction of the developing roll (R0) adjacent to the developing roll housing section (42);
3) and a second developer stirring area (44) disposed adjacent to the first developer stirring area (43) and on the side opposite to the developing roll (R0). The first developer stirring area (43) and the second developer stirring area (44) are separated by a partition wall (45) except for the both ends in the axial direction, and are connected at both ends in the axial direction. The first conveying member (R1) disposed in the first developer stirring area (43) and the second conveying member (R2) disposed in the second developer stirring area (44) transfer the developer in opposite directions. And stir while transporting. Therefore, the developer is conveyed and stirred while circulating in the first developer stirring area (43) and the second developer stirring area (44).

When being transported and agitated, the rotating shaft (56) of the first transporting member (R1) and the second transporting member (R2) extending in the transporting direction of the developer rotates around the axis in the transporting direction. By rotating, the spiral rotary wing (57) fixed to the outer periphery of the rotary shaft (56) rotates around the axis. When the helical rotor (57) rotates, a plurality of projecting members (58) projecting from the outer peripheral portion of the helical rotor (57) in the upstream direction in the transport direction are formed by the helical rotor (5).
With the rotation of 7), the developer is moved around the axis, and the developer adjacent to the upper end side of the outer peripheral portion of the spiral rotating blade (57) and the upstream side is accommodated in the developing container (41). The developer is mixed with the developer below from the upper end side of the outer peripheral portion of the spiral rotor (57). The first developer stirring area (4
The developer stirred while being transported in 3) is transported to the development area (Q2) by the development roll (R0) stored in the development roll storage section (42).

Therefore, the developer device according to the second invention of the present application provides the projecting member (5) on the outer peripheral portion of the spiral rotary blade (57).
According to 8), the floating toner (69) floating on the upper surface of the developer adjacent to the outer peripheral portion of the spiral rotor (57) and the stored developer (68) can be stirred. Further, the first and second transport members (R1, R2,
R2), the projecting length of the projecting member (58) is shorter than the pitch of the spiral rotor (57), and the projecting member (5)
Even when 8) rotates, the resistance with the developer is small, and even when the amount of the developer is relatively large, a large force is not required for rotation around the axis. Therefore, the first and second transfer members (R1, R
The rotation force of 2) does not decrease, and the first and second transport members (R
The force for transporting the developer of (1, R2) does not decrease.
Therefore, the swelling (68a) of the developer due to a decrease in the force for transporting the developer is not formed, and the floating toner (69) on the upper surface of the developer can be involved.
Even if the developer amount is relatively large, the floating toner (69)
Can be mixed and conveyed from the upper end side of the outer peripheral portion of the spiral rotating blade (57) to the developer below. Further, since the swelling of the developer (68a) is not formed, the swelling of the developer (68a) does not contact the upper wall of the developing container (41). Therefore, a small-sized developing container (41) in which the wall of the developing container (41) is located above the first and second transport members (R1, R2) can be used.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Embodiment 1 of the present invention is based on the following requirement (AB0) in the first invention and the second invention of the present application.
(AB01) The projecting member (5) integrally formed with the spiral rotor (57).
8). (Operation of the First Embodiment) In the first embodiment of the present invention having the above-described configuration, the protruding member (58) is formed integrally with the spiral rotor (57). Therefore, the projecting member (58) and the spiral rotor (57) do not need to be manufactured separately, so that the number of parts can be reduced and the manufacturing cost of the conveying members (R1, R2) can be reduced. it can.

[0025]

Next, examples (embodiments) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In order to facilitate understanding of the following description, arrows X, Y,
The orthogonal coordinate axes X axis, Y axis, and Z axis are defined in the Z direction, and the arrow X direction is forward, the arrow Y direction is left, and the arrow Z direction is upward. In this case, the direction opposite to the X direction (front) (−X direction) is backward, the direction opposite to the Y direction (left) (−Y direction) is right, and the direction Z (upward) is opposite (−Z direction). Is below. Also referred to as the front-rear direction or the X-axis direction including the front (X direction) and the rear (-X direction), and the left-right direction or the Y-axis direction including the left (Y direction) and the right (-Y direction). Good,
It is referred to as a vertical direction or a Z-axis direction including the upper part (Z direction) and the lower part (-Z direction). Furthermore, in the figure, those with "•" in "○" mean arrows pointing from the back of the paper to the front, and those with "x" in "○" are from the table on the paper. It shall mean an arrow pointing to the back.

(Embodiment) FIG. 1 is an overall explanatory view of an image forming apparatus provided with an embodiment of a developer conveying member and a developing device according to an embodiment of the present invention. FIG. 2 is an enlarged explanatory view of the developing device shown in FIG. FIG. 3 is a sectional view taken along the line III-III of FIG. FIG. 4 is a sectional perspective view of a developer retaining portion formed at the developer outlet. FIG. 5 is an explanatory view of first and second transport members provided in the developing device. FIG. 5A is an enlarged view of a main part of the transport member, and FIG. 5B is a sectional view taken along line VB-VB of FIG. 5A. In FIG. 1, an image forming apparatus U includes a digital copying machine U1 as an image forming apparatus main body having a platen glass (transparent platen) A1 on an upper surface and an automatic removably mounted on the platen glass A1. And a document feeder U2. The automatic document feeder U2 is adapted to copy documents Gi (i = 1, 2, 2, 3) of various sizes to be copied.
..) Are placed on top of each other. The document placed on the document feed tray TRk is transported to a copy position on the platen glass A1, and the copied document Gi is discharged to the document discharge tray TRh.

The copying machine U1 has a UI (user interface), an image input terminal IIT (hereinafter referred to as IIT) as an image reading unit and an image as an image recording operating unit which are sequentially arranged below the platen glass A1. Output Terminal IOT (I
OT) and an IP provided between the IIT and the IOT.
S (image processing system).

The UI is a portion for the user to input an operation command signal such as a copy start command, and has a display section, a copy start button, a copy number input key, and the like. On the display unit of the UI, information on the current setting state of the image forming apparatus U is displayed. An IIT as an original reading device disposed below the transparent platen glass A1 on the upper surface of the copying machine main body U1 includes an exposure system registration sensor (platen registration sensor) Sp and a image writing device arranged at a platen registration position (OPT position). The exposure optical system 1 is provided. This exposure optical system 1
Has a movable lamp unit 2, and the lamp unit 2 is configured by integrating a lamp 3 for document illumination and a first mirror 4. Further, the exposure optical system 1 has a movable mirror unit 5 that moves at half the speed of the lamp unit 2. The movable mirror unit 5 includes a second mirror 6 and a third mirror 7.

Then, the lamp unit 2 moves in the horizontal direction in FIG. 1 in parallel with the original, and the moving mirror unit 5 moves at a speed half the moving speed of the lamp unit 2 and a distance of 1/2. , The distance between the document Gi and the lens 8 is kept constant. During this time, the reflected light of the document Gi illuminated by the lamp 3 passes through the exposure optical system 1 and passes through the CCD (solid-state imaging device). Element). The CCD has a function of converting the original reflected light converged on the imaging surface into an electric signal.

The IPS has image read data output means 11 for adjusting the gain of an analog electric signal of a read image obtained by the CCD of the IIT, converting the analog signal into a digital signal, performing shading correction and the like, and outputting the digital signal. ing. The IPS has a write image data output unit 12 to which the image read data output from the image read data output unit 11 is input, and the write image data output unit 12 temporarily stores the image data. It has an image memory 13 to be used. The write image data output unit 12 has a function of performing data processing such as density correction and enlargement / reduction correction on the input image read data and outputting the image read data to the IOT as write image data (laser drive data). ing.

The IPS write image data output means 12
The laser drive signal output device 14 of the IOT to which the image write data (laser drive data) output by the IOT is input, outputs a laser drive signal corresponding to the input image data to an ROS (optical write scanning device, that is, a latent image). Forming device). The ROS scans the electrostatic latent image writing position Q1 on the surface of the rotating image carrier 16 with the laser beam L modulated by the input laser drive signal. The image carrier 1
6 around the latent image writing position Q along the rotation direction.
A charging charger 17 is arranged upstream of 1
A developing device D is sequentially arranged at a developing position Q2 downstream of the latent image writing position Q1, a transfer unit 19 is arranged at a transfer position Q3, and a cleaner unit 20 is arranged further downstream thereof. A toner image density sensor SNd for detecting the density of a small area toner image (that is, a patch) formed on the image carrier 16 is disposed between the development position Q2 and the transfer position Q3.

In the copying machine body U1, a first paper supply tray T1 and a second paper supply tray T2 for sequentially storing image recording sheets, a temporary stock used for duplex copying, etc. Intermediate tray T0, third paper tray T3,
A fourth paper supply tray T4 and a fifth paper supply tray T5 for storing a large number of sheets are detachably stored. The intermediate tray T0 is an intermediate tray used for circulating the recording sheet (hereinafter, sheet) S on which the first copy has been performed at the time of double-sided copying or multiple copying, and re-transmitting the recording sheet S to the transfer position Q3.

At the upper right side of the first paper feed tray T1, a manual feed tray 21 is provided. Each sheet sent from the manual feed tray 21 and each of the paper feed trays T1 to T5 passes through a first sheet conveying path 22 and is transferred to the transfer position Q3.
To be transported. First sheet transport path 22
Is detected by the sheet registration sensor SNy. At the end of the first sheet conveying path 22, the sheet S conveyed is temporarily stopped upstream of the transfer position Q3 in the sheet conveying direction, and then the transfer position Q3
Gate 23 and register roll 24 for carrying in
Is arranged. The transfer device 19 arranged at the transfer position Q3 transfers the toner image on the surface of the image carrier 16 to the sheet S passing through the transfer position Q3. After the toner remaining on the surface of the image carrier 16 that has passed the transfer position Q3 is recovered by the cleaner unit 20, the charger 17 uniformly charges the surface again.

The sheet S to which the toner image has been transferred at the transfer position Q3 is conveyed to the fixing position Q4 through the conveyance belt 26 of the second sheet conveyance path 25 connected to the sheet discharge tray TR. At the fixing position Q4, a pair of fixing rolls 27 and 2 including a heating roll 27 and a pressure roll 28 are provided.
A fixing device F having a fixing position Q4
Is configured to fix the unfixed toner image on the sheet S passing through the sheet S by heating and pressing. The fixing roll 27
A fixing heater 27h is built therein. In addition,
The surface temperature of the heating roll 27 is detected by a fixing temperature sensor SNt, and a fixing device discharge sensor SNf is disposed immediately after the fixing device F. A discharge roller 29 for discharging the sheet S to the sheet discharge tray TR downstream of the fixing position Q4 is provided in the second sheet conveying path 25.
Is provided.

In the second sheet conveying path 25, a switching gate 31 is disposed upstream of the discharge roller 29.
The switching gate 31 is used when switching the transport direction of the sheet S on the second sheet transport path 25 to the direction of the sheet circulation path 32 or the sheet discharge tray TR. The sheet circulation path 32 is connected to a sheet reversing path 34 and the intermediate tray T0 via a switching gate 33. The switching gate 33 directs the sheet S of the sheet circulation path 32 to the sheet reversing path 34 when performing double-sided copying, and directly to the intermediate tray T0 when performing multiple copying. The sheet-shaped and comb-shaped mylar gate 36 provided in the sheet reversing path 34 allows the sheet S to move downward by elastic deformation when the passing sheet S is conveyed downward. When the sheet S that has passed through the gate 36 is switched back and conveyed upward, the sheet S is guided in the direction of the intermediate tray T0. Sheet S once stored in intermediate tray T0
Are transported again from the intermediate tray T0 to the transfer position Q3 by the first sheet transport path 22.

In FIG. 2, a developing device D arranged opposite to the image carrier 16 in the developing area Q2 includes a negatively charged toner and a positively charged magnetic carrier.
It has a developing container 41 for storing the component developer. The developing container 41 includes a developing roll accommodating section 42 for accommodating the developing roll R0, and a first
It has a first developer reservoir 43 that is a developer stirring region and a second developer reservoir 44 that is a second developer stirring region adjacent to the first developer reservoir 43. As shown in FIG. 3, between the first developer reservoir 43 and the second developer reservoir 44, partition walls 45 are provided at portions other than both ends thereof, and the first developer reservoir 43 is provided. 43
The second developer reservoir 44 is connected at the connection portions E at both ends in the front-rear direction (X-axis direction). In FIG. 3, a first transport member R is provided in the first developer pool 43.
1 is disposed, and a second transport member R2 is disposed in the second developer reservoir 44.

As shown in FIG. 2, a layer thickness regulating member 47 for regulating the layer thickness of the developer on the developing roll R0 is disposed in the developing roll accommodating section 42. Further, a developer supply port 48 is formed on the upper surface of the second developer reservoir 44. 2 to FIG.
The developer reservoir 44 is provided with a developer stagnation portion 50 swelling outward from the outer surface of the developing container 41. The developer retaining section 50 includes a bottom surface 51a, an upper surface 51b,
4, an upstream end wall 51 disposed downstream of the developer conveyed through the developer reservoir 44.
d, and an outwardly projecting wall 51 having a downstream end wall 51e. The downstream end wall 51e (see FIGS. 3 and 4)
), A developer outlet 52 is formed near the developer reservoir 44. The developer discharged from the developer discharge port 52 is collected in a developer collection container 54 through a developer discharge path 53.

The developer reservoir 50 is a region of the second developer reservoir 44 shown in FIG. 3 and a region partitioned from the first developer reservoir 43 by the partition wall 45 (a front-rear connection). (Excluding the portion E). The area from the first developer reservoir 43 where the surface height of the developer fluctuates due to the rotation of the developing roll R0 is separated from the partition wall 45.
This is a region where the flow of the developer is limited in a certain direction by being partitioned by the above, and a region where the upper surface position of the developer is stable.
Note that the developer supply port 48 is formed downstream of the position of the developer stagnation section 50 in the transport direction in order to reduce the rate at which the supplied new developer stagnates in the developer stagnation section 50. . As described above, from the elements indicated by the reference numerals 42 to 53, the developing containers 41 (42 to
3) is configured.

In FIG. 3, driven gears G1 and G2 meshing with each other are fixed to the rear ends (-X side ends) of the shafts of the first and second transport members R1 and R2.
The gear G1 of the first transport member R1 is a gear G0 attached to the rear end (the -X side end) of the shaft of the developing roll R0.
Are engaged. When a rotational force is transmitted to the gear G0 by a rotation drive device (not shown) and the gear G0 rotates, the gears G1 and G2 also rotate in opposite directions. As shown in FIG. 3, the first and second developer reservoirs 43 are formed by the first and second transport members R1 and R2 which rotate integrally with the gears G1 and G2.
And the developer circulates in 44. The developing roll R0 has a configuration in which a sleeve is provided outside a magnet roll, and is conventionally known. With the rotation of the developing roll R0, the developer in the first developer pool 43 adheres to the surface of the developing roll R0 and is transported to the developing position Q2.

Since the first and second transport members R1 and R2 have the same structure, the second transport member R2 will be described as a representative.
In FIG. 5, the second conveying member R2 of the present embodiment has a rotating shaft 56 having a diameter a = 8 mm and a height b = 5 mm from the outer periphery of the rotating shaft 56 disposed on the outer periphery of the rotating shaft 56.
(Outer diameter a + 2b = 18 mm) and a spiral rotating blade 57 having a pitch c = 25 mm. The second transport member R2
A projecting member 58 is provided on the outer peripheral portion of the surface of the spiral rotary blade 57 on the upstream side in the transport direction of the two-component developer.
And are integrally molded. The protruding member 58 has a protruding length d = 3 mm, which is the length of the protruding member 58 in the transport direction, and has a cross-sectional shape of 1.5 mm in a direction orthogonal to the rotation shaft 56.
It is a square member of × 1.5 mm, and is arranged at four locations at equal intervals during one pitch of the helical rotor 57.
The rotation speed of the first and second transport members R1, R2 is 18
It is set to 0 rpm. The first transport member R
From the first and second transport members R2, the transport member (R1
+ R2).

In FIG. 2, a two-component developer having a high toner concentration stored in a developer storage container 61 (hereinafter, referred to as a “high-concentration developer”) is provided in a developer supply port 48 of the developing container 41.
Are supplied from the developer transport auger 62. 2 and 3, the developer transport auger 62
Is rotated by a developing device motor M via a clutch 64.

In FIG. 2, the developing device motor M is driven by a developing device motor drive circuit 66 controlled by a controller C which controls the operation of the copying machine U1. While the developing device motor M is being driven, when the clutch 64 is on, the auger rotating shaft 63 and the developer conveying auger 62 are driven to rotate. At this time, the high-concentration developer for replenishment stored in the developer storage container 61 is supplied from the developer supply port 48 into the developer container 41 by the developer transport auger 62. The replenishment of the high-concentration developer is performed when the toner concentration Tb in the container detected by the in-container toner concentration sensor SNv (see FIG. 2) disposed in the developing container 41 during normal use is equal to or lower than the reference value Tbo. Will be Note that the high-density developer is supplied by the toner image density sensor SNd.
This is also performed when the density of the developed toner image detected in (see FIG. 1) is lower than the reference value. Further, the developing device motor M
Is transmitted to the gear G0 via the clutch 67.

(Operation of Embodiment) In FIG. 1, the surface of the image carrier 16 is uniformly charged to a negative polarity by the charging device 17. Next, the image carrier 1 is exposed by ROS.
On the surface of No. 6, an electrostatic latent image is formed. The first and second transport members R1 and R2 accommodated in the first and second developer reservoirs 43 and 44 in the developing container 41 of the developing device D rotate in directions opposite to each other, and a developer supply port is provided. The high-concentration developer supplied from 48 is stirred and conveyed, and is made into a homogeneous two-component developer triboelectrically charged by the mixing action of the toner and the carrier.

FIG. 6 is an explanatory diagram of the operation of the first and second transport members provided in the developing device according to the embodiment of the present invention. In FIG. 6, the bulk of the developer 68 (the amount of the developer stored in the developing container 41 and the height of the upper surface of the stored developer) is at the upper end of the first and second transport members R1 and R2. When the developer reaches the position, a recess 68a of the developer is formed in the developer 68 of the developer pools 43 and 44 after the spiral rotor has passed. The floating toner 69 which is supplied into the developing container 41 and floats on the upper surface of the developer 68 falls into the developer recess 68a. The floating toner 69 that has fallen into the developer recess 68a is entangled in the developer in the developer reservoirs 43 and 44 by the projecting member 58,
Mixed. The uniformly mixed two-component developer is deposited in a layer on the peripheral surface of the developing roll R0. The developer on the surface of the developing roll R0 is formed into a uniform layer by the layer thickness regulating member 47. The uniform developer layer formed on the surface of the developing roll R0 is applied to the image carrier 16 in the developing area Q2.
The upper electrostatic latent image is developed into a toner image.

A sheet S such as a recording sheet or a transparent transfer material on which the toner image is transferred is taken out from the sheet feed trays T0 to T5, conveyed, temporarily stopped by a registration gate 23, and then stopped by a registration roller 24. Is transferred to the transfer position Q3 between the image carrier 16 and the transfer device 19 at the timing shown in FIG. At the transfer position Q3, the toner image on the image carrier 16 is transferred onto the sheet S by the transfer device 19.
Then, the sheet S on which the toner image has been transferred is fixed to the fixing device F.
Is heated and fixed, and is discharged to the sheet discharge tray TR. After the transfer of the toner image, the toner remaining on the surface of the image carrier 16 is scraped off by the cleaner unit 20.

When the copying operation as described above is repeated,
The toner in the developer accommodated in the developing container 41 of the developing device D in FIG. 2 is gradually consumed, and the ratio of the toner to the carrier, that is, the toner concentration decreases.
This change in toner density is detected by an in-container toner density sensor SNv provided in the developing container 41. When the toner concentration Tb in the container falls below an appropriate range necessary for development, the controller C turns on the clutch 64 to drive the developer transport auger 62, and the developer storage container 6
1 is supplied to the developing container 41 from the developer supply port 48.

On the other hand, the carrier in the developer in the developing container 41 is not consumed by the developing operation, but is agitated together with the toner in the developing container 41 or the magnetic force of the magnet roller of the developing roll R0. Due to the influence and the contact with the image carrier 16 and the toner, the toner adheres to the carrier surface, and the surface is gradually contaminated and deteriorated. When the carrier deteriorates in this way, the charging performance of the developer is reduced, and a predetermined amount of charge cannot be given to the toner, and the image quality is reduced. 2 and 3, the developer circulating in the first and second developer reservoirs 43 and 44 is
The developer stays in the developer staying section 50 formed by the outwardly projecting walls 51 formed on the four side walls. The developer that is retained in the developer retaining section 50 and that is close to the developer reservoir 44 moves while being dragged by the developer being conveyed through the developer reservoir. The developer is discharged to a developer discharge passage 53 from a developer discharge port 52 formed in a portion of the downstream end wall 51e near the developer reservoir 44. The discharged developer is collected in the developer collection container 54.

The developing device of the embodiment of the present invention extends in the axial direction from the outer peripheral edge of the helical rotary blade 57 even when a small-diameter developer composed of a toner and a carrier having a small particle diameter and having poor fluidity is used. Since the projecting member 58 rotates around the axis and entrains the floating toner, a sufficient charge amount can be obtained until the replenishment toner is conveyed to the development area Q2. In addition, the projecting length of the projecting member 58 of the first and second transport members R1 and R2 is shorter than the pitch of the helical rotary blade 57, and the resistance to the developer is reduced even when the projecting member 58 rotates around the axis. The rotation force of the first and second transport members R1 and R2 does not decrease. For this reason, the first and second transport members R
1, There is no decrease in the force for transporting the R2 developer. Therefore, since the developer swelling 68a due to a decrease in the force for transporting the developer cannot be performed, a small developing container in which the wall of the upper lid of the developing container 41 closes near the first and second transport members R1 and R2 is used. Even in this case, the developer does not rub against the upper lid, so that the chargeability and the transfer efficiency do not change due to the change in the surface of the toner and the carrier.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various changes can be made. Modified embodiments of the present invention will be exemplified below. (H01) The developer transport member of the present invention may be a developer transport member in a conventionally known various developer container or a developer storage container for storing a developer to be replenished in the developer container, or the developer transport member. The present invention is also applicable to a developer conveying member that conveys a developer. (H02) The present invention can be applied to analog copying machines, printers, facsimile machines, etc., in addition to digital copying machines. (H03) Instead of forming the developer storage container with one developer storage container 61 containing a high-concentration developer having a high toner concentration in the above embodiment, two storage containers, a toner storage container and a carrier storage container, are used. It is possible to configure. Further, the developer storage container includes a container storing a high-concentration developer having a high toner concentration and a toner storage container.
It is possible to configure with individual containers. (H04) The shape of the projecting member 58 of the first and second transport members R1 and R2 provided in the embodiment of the present invention can be changed to various shapes such as an elongated plate shape and a hollow cylindrical member. (H05) The number of the projecting members 58 of the first and second conveying members R1 and R2 provided in the embodiment of the present invention may be two or more during one pitch of the helical rotor if the cost and the manufacturing method are not specified. It is possible to provide.

[0050]

The developer conveying member and the developing device of the present invention described above have the following effects. (E01) Even when the developer amount in the developing container is relatively large,
Provided is a developing device including a developer transporting member capable of agitating the stored developer by taking floating toner floating on the upper surface of the developer stored in the developing container into the stored developer. can do. (E02) Even when a developer having a small particle diameter is used, the developer transport member and the developing device of the present invention can take in the floating toner into the stored developer and stir the toner.

[Brief description of the drawings]

FIG. 1 is an overall explanatory diagram of an image forming apparatus including an embodiment of a developer conveying member and a developing device according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of the developing device shown in FIG. 1;

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional perspective view of a main part shown in FIG. 3;

FIG. 5 is a view showing first and second units provided in the developing device.
5A is an enlarged view of a main part of the conveying member, and FIG. 5B is a cross-sectional view taken along line VB-VB of FIG. 5A.

FIG. 6 is an explanatory diagram of an operation of first and second transport members provided in the developing device according to the embodiment of the present invention.

7 is an explanatory view of a developer conveying member described in Japanese Patent Application Laid-Open No. 4-254879, FIG. 7A is a partially enlarged explanatory view of the developer conveying member, and FIG. 7B is VIIB of FIG. 7A.
FIG. 7C is an explanatory view showing a state of the developer conveying member in a developer container containing a normal amount of developer, and FIG. 7D is a view showing the state of the developer container containing a large amount of developer. FIG. 3 is an explanatory diagram illustrating a state of the developer conveying member.

8 is an explanatory view of a developer conveying member described in Japanese Patent Application Laid-Open No. 9-26694, FIG. 8A is a partially enlarged explanatory view of the developer conveying member, and FIG. 8B is a VIIIB of FIG. 8A.
FIG. 8C is a sectional view taken along the line VIIIB, and FIG. 8C is a diagram illustrating a state of the developer conveying member in the developing container in which the developer is stored.

9 is an explanatory view of a developer conveying member created for an experiment, FIG. 9A is an enlarged explanatory view of a main part of the developer conveying member, and FIG. 9B is a sectional view taken along line IXB-IXB of FIG. 9A. It is.

[Explanation of symbols]

Q2: developing area, R0: developing roll, R1: first conveying member, R2: second conveying member R1 + R2: conveying member 41: developing container, 42: developing roll accommodating section, 43: first
Developer stirring area, 44: second developer stirring area, 45: partition wall, 56: rotating shaft, 57: spiral rotating blade, 58: projecting member

Claims (2)

[Claims] 1. A developer conveying member having the following requirements: (A01) a rotating shaft extending in a developer conveying direction and rotating around an axis in the conveying direction; A helical rotor that is fixed and rotates around the axis, and protrudes from the outer periphery of the helical rotor to the upstream side in the transport direction, and rotates the developer around the axis with the rotation of the helical rotor. A plurality of projecting members for moving the developer to mix the developer adjacent to the upstream side and the upper end side of the outer periphery of the spiral rotor with the lower developer from the upper end side of the outer periphery of the spiral rotor. (A02) The protruding member, wherein the protruding length of the protruding member is shorter than the pitch of the helical rotor, and the interval around the axis is arranged to be constant. 2. A developing device having the following requirements: (B01) a developing roll for transporting a developer to a developing area; (B02) a developing roll accommodating section accommodating the developing roll; A first developer stirring region extending in the axial direction of the developing roll adjacent to the roll accommodating portion; and a first developer stirring region adjacent to the first developer stirring region and opposite to the developing roll and excluding both ends in the axial direction. The first part is a partition wall.
A second developer stirring area which is partitioned from the developer stirring area and has both ends in the axial direction connected to the first developer stirring area and formed between the partition wall and a container outer wall extending along the partition wall. Having a developer container for containing the developer,
(B03) a first transport member disposed in the first developer stirring area and agitating while transporting the developer in the axial direction of the developing roll; and (B04) a developer disposed in the second developer agitating area and stirring the developer. (B05) a rotating shaft extending in the carrying direction of the developer and rotating around an axis in the carrying direction, and being fixed to the outer periphery of the rotating shaft. A spiral rotor that rotates about the axis,
Projecting upstream from the outer periphery of the spiral rotor in the transport direction, moving the developer around the axis with the rotation of the spiral rotor, at the upper end side of the outer periphery of the spiral rotor and A first projecting member having a plurality of projecting members for mixing the developer adjacent to the upstream side with a developer below from an upper end side of an outer peripheral portion of the spiral rotor;
(B06) The projecting member wherein the projecting length of the projecting member is shorter than the pitch of the helical rotor and the interval around the axis is fixed.