JP2001249527A - Image forming machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To very excellently carry the developer through an upstream-side path and a downstream-side path in a developing container, and further to very uniformly mix toner with carrier particles and also to sufficiently electrify the toner by sufficiently stirring developer, especially, in the upstream-side path and/or to very uniformly distribute the developer all over a downstream- side path, especially, in the downstream-side path. SOLUTION: A downstream-side carrying and stirring mechanism and an upstream-side carrying and stirring mechanism include many paddle pieces disposed on the peripheral surface of a rotary shaft at some intervals in a peripheral direction, and the respective paddle pieces are extended in a radial direction from the peripheral surface of the rotary shaft and in an axial direction between spiral blades, then the edges of the respective paddle pieces in the radial direction are positioned on the inside in the radial direction from the outer periphery of the spiral blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a developing means for developing an electrostatic latent image formed on an image bearing means into a toner image.

[0002]

2. Description of the Related Art As an image forming machine such as a copying machine, a printing machine and a facsimile, an electrostatic latent image is formed on an image bearing means,
Image forming machines that develop such an electrostatic latent image into a toner image and transfer the toner image to a sheet member are widely used in practice. Such an image forming apparatus includes, in addition to the image carrying means, an electrostatic latent image forming means for forming an electrostatic latent image on the image carrying means, and an electrostatic latent image on the image carrying means for developing the toner into a toner image. Developing means, transferring means for transferring the toner image on the image bearing means onto the sheet member, and carrying the toner remaining on the image bearing means after transferring the toner image on the image bearing means onto the sheet member Cleaning means for removing from the means. Further, it has already been proposed and put to practical use to provide a toner recycling means for recycling the toner removed from the image bearing means by the cleaning means to the developing means. Regarding an image forming machine provided with a toner recycling means, for example,
5-101979, JP-A-63-8682, JP-A-63-29776 or U.S. Pat.
768, 055.

The developing means generally includes a developing container for storing a developer composed of toner and carrier particles, a developer applying means for applying the developer in the developing container onto the image bearing means, and a developing container. Means for replenishing the toner with the toner, and the toner concentration in the developer contained in the developing container (that is, the toner weight TW with respect to the developer weight DW).
(TW / DW), and a toner replenishment control means for controlling the operation of the toner replenishment means. The toner replenishment control unit controls the toner replenishment unit by comparing the detection value of the toner density detection unit with a threshold. Normally, the toner concentration detecting means is constituted by a magnetic permeability detector whose output voltage changes in accordance with the magnetic permeability of the developer, and the output voltage increases when the toner concentration decreases. The threshold is a voltage value. If the toner density indicated by the detected value of the toner density detecting means exceeds the toner density indicated by the threshold, and therefore the output voltage of the magnetic permeability detector does not reach the threshold, the toner replenishing means is deactivated. However, when the toner density indicated by the detected value of the toner density detecting means becomes equal to or lower than the toner density indicated by the threshold value, and therefore, the output voltage of the magnetic permeability detector becomes equal to or higher than the threshold value, the toner replenishing means is activated.

When the toner recycle means is provided, the toner replenishment means includes a new toner storage means for storing new toner, a recycled toner receiving chamber for receiving recycled toner recycled by the toner recycle means, and a new toner storage means. A toner mixing chamber for mixing new toner supplied from the toner container and toner supplied from the recycled toner receiving chamber, and a recycled toner feeding means for supplying recycled toner in the recycled toner receiving chamber to the mixing chamber. And a toner carrying means for carrying the toner in the mixing chamber into the developing container.

[0005] The toner carrying means of the toner replenishing means includes an electric motor for replenishing the toner. When the toner replenishing means is activated, the electric motor for replenishing toner is normally energized repeatedly at predetermined intervals for a predetermined time. You.

In the developing container of the developing means,
A stirring means is provided. In a typical example, a circulation path including an upstream path and a downstream path extending in parallel in the width direction is defined in the developing container, and the upstream path and the downstream path are both ends in the width direction. The parts are communicated with each other. The conveying / stirring means includes an upstream conveying / stirring mechanism disposed on the upstream path and a downstream conveying / stirring mechanism disposed on the downstream path. The upstream conveying / stirring mechanism is composed of a rotating shaft extending in the width direction in the upstream path and a spiral blade disposed on the peripheral surface of the rotating shaft, and the downstream conveying / stirring mechanism has a width in the downstream path. And a spiral blade disposed on the peripheral surface of the rotating shaft. The developer applying means in the developing means includes a sleeve member extending in the width direction along the downstream path, pumps up the developer existing in the downstream path in the developer pumping area, and statically operates on the image bearing means in the developing work area. Applies to electro-latent images. A developer regulating member for regulating the amount of developer held on the peripheral surface of the sleeve member between the developer pumping area and the developing work area is also provided. At both ends of the sleeve member, stationary seal members extending in an arc along the sleeve member are provided.

[0007]

However, the conventional image forming apparatus has the following problems to be solved. As described above, in a typical example of the developing means, a circulation path including an upstream path and a downstream path extending in parallel in the width direction is defined in the developing container, and the upstream path and the downstream path are defined. The side path is communicated with each other at both ends in the width direction. And, on the upstream route,
A stirring mechanism is arranged, and a downstream transport / stirring mechanism is arranged on the downstream path. In the circulation path in the developing container in such a developing means, in addition to the developer being sufficiently satisfactorily conveyed through the upstream path and the downstream path, the developer is sufficiently stirred especially in the upstream path. Therefore, it is important that the toner and the carrier particles are sufficiently uniformly mixed and the toner is sufficiently charged. In particular, in the case of the downstream path, the developer is sufficiently uniformly distributed throughout the downstream path. It is important that If the distribution of the developer in the downstream path becomes non-uniform, the developer pumped up by the developer application unit becomes non-uniform in the width direction, and as a result, the development tends to be non-uniform. However, in the conventional image forming apparatus, the above requirements cannot be sufficiently satisfied in the upstream path and / or the downstream path of the circulation path.

Therefore, a technical problem of the present invention is that a circulation path including an upstream path and a downstream path extending in parallel in the width direction is defined in the developing container. The downstream path is communicated with each other at both ends in the width direction, the upstream path is provided with an upstream transport / stirring mechanism, and the downstream path is provided with the downstream transport / stirring mechanism. In addition to the fact that the developer is sufficiently satisfactorily conveyed through the upstream path and the downstream path in the image forming machine, especially in the upstream path, the developer is sufficiently agitated and the toner and the carrier particles are sufficiently uniform. And / or to ensure that the toner is sufficiently charged and / or to distribute the developer sufficiently uniformly throughout the downstream path, especially in the downstream path. A.

[0009]

According to the present invention, there is provided an image forming apparatus which achieves the above technical object, comprising: an image bearing means;
Electrostatic latent image forming means for forming an electrostatic latent image on the image carrying means, developing means for developing the electrostatic latent image on the image carrying means into a toner image, and Transfer means for transferring the toner image on the sheet member, and removing the toner remaining on the image bearing means after transferring the toner image on the image bearing means onto the sheet member from the image bearing means A developing container containing a developer composed of toner and carrier particles, and a developer for applying the developer in the developing container onto the image bearing unit. An application unit, and a conveying / stirring unit disposed in the developing container, wherein a circulation path including an upstream path and a downstream path extending in parallel in the width direction is provided in the developing container. The upstream path and the downstream path are defined at both ends in the width direction. There has been caused to communicate with each other,
The conveying / stirring means includes an upstream conveying / stirring mechanism disposed on the upstream path, and a downstream conveying / stirring mechanism disposed on the downstream path. A rotary shaft extending in the width direction in the upstream circulation path and a spiral blade disposed on a peripheral surface of the rotation shaft, and the downstream transport / stirring mechanism extends in the width direction in the downstream circulation path. The developer applying means includes a sleeve member extending in a width direction along the downstream path, and a sleeve member extending in a width direction along the downstream path. In the image forming apparatus, the developer present in the image forming apparatus is pumped up to the peripheral surface of the sleeve member and applied to the image bearing means. And a number of paddle pieces arranged on the rotating shaft, Extending radially from the surface and axially between the spiral blades, the radial leading edge of each of the paddle pieces is located radially inward of the outer peripheral edge of the spiral blade, and / or The stirring mechanism includes a large number of paddle pieces arranged on the peripheral surface of the rotating shaft at intervals in the circumferential direction, each of the paddle pieces extending radially from the peripheral surface of the rotating shaft and between the spiral blades. In the axial direction, and the radial leading edge of each of the paddle pieces is located radially inward of the outer peripheral edge of the spiral blade.

[0010] Preferably, in the downstream conveying / stirring mechanism, the paddle pieces are disposed substantially uniformly over substantially the entire developing action area of the sleeve member. Each extends continuously between the spiral blades in the axial direction. In the upstream conveying / stirring mechanism, it is preferable that the paddle piece does not exist in an axially intermediate region between the spiral blades in at least a part of the rotating shaft. Conveniently, the radial length from the peripheral surface of the rotary shaft to the radial leading edge of the paddle piece is approximately half the radial length from the peripheral surface of the rotary shaft to the outer peripheral edge of the spiral blade. is there. In a preferred embodiment, the developing means includes a toner replenishing means for replenishing toner in the developing container, and the toner replenishing means carries toner into one end in the width direction of the upstream path, and The side transport / stirring mechanism transports the developer in the upstream path in a direction from the one end to the other end, and the downstream transport / stirring mechanism transports the developer through the downstream path in the upstream path. The upstream side conveying / stirring mechanism, the arrangement density of the paddle pieces at one end and in the vicinity thereof is higher than that of the paddle pieces at the other end and in the vicinity thereof. It is made smaller than the installation density.

[0011]

In the image forming apparatus of the present invention, the downstream transport / stirring mechanism and / or the upstream transport / stirring mechanism provided in the developing container has a unique configuration provided on the peripheral surface of the rotating shaft. In addition to the fact that the developer is sufficiently satisfactorily conveyed through the upstream path and the downstream path by the action of the large number of paddle pieces, especially in the upstream path, the developer is sufficiently agitated and the toner and the carrier particles become Are mixed sufficiently uniformly and the toner is sufficiently charged, and / or the developer is sufficiently uniformly distributed throughout the downstream path, especially in the downstream path.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image forming machine constructed according to the present invention will be described below in detail with reference to the accompanying drawings.

[0013]Overview of overall configuration of image forming machine  Referring to FIG. 1, the image forming machine is indicated by arrow 4
The rotating drum 2 includes a rotating drum 2 which can be rotated in a direction. This
The image bearing member 6 is disposed on the peripheral surface of the rotary drum 2.
I have. The image bearing member 6 constituting the image bearing means is provided with an appropriate electrostatic
It can be formed from a photoreceptor. The rotating drum 2 is an arrow
When rotated in the direction indicated by 4, the image bearing member 6 rotates.
Through an endless path defined by the peripheral surface of the transfer drum 2
The electrostatic latent image forming area 8, the developing area 10,
Passing through the imaging area 12 and the cleaning area 14 sequentially
It is. In the electrostatic latent image forming area 8, the corona discharger 16
Causes the surface of the image bearing member 6 to have a specific polarity evenly.
Charged and then shaped as schematically shown by arrow 18
Light is applied to the image bearing member 6 corresponding to the image to be formed.
The charges are selectively eliminated, and thus the image bearing member 6
An electrostatic latent image is formed thereon. In the development area 10, all
Image bearing member by the action of developing means, designated by the numeral 20
6. The toner is applied to the electrostatic latent image on
Is developed. In the transfer area 12, on the image bearing member 6
Sheet member on which the toner image is conveyed through the transfer area 12
(Not shown). In this case, plain paper
Is transferred from the corona discharger 22 to the back of the sheet member such as
An electric current is applied. In the cleaning area 14,
By the action of the cleaning means, which shows the body at number 24,
Residual toner is removed from the image bearing member 6. Image formation
The toner removed from the image bearing member 6 is
From the cleaning means 24 to the developing means 20
A toner recycling means 26 (FIG. 4) is also provided.
Developing unit 20, cleaning unit 24, and toner recycle
The cling means 26 will be described in more detail below.

[0014]Outline of developing means  Referring to FIG. 2 together with FIG. 1, the developing means 20
A developing container 28 is included. This developing container 28 is located on the lower side.
It is composed of a material 30 and an upper member 32. Lower member
30 designates a bottom wall 34, a rear wall 36 and both side walls 38 and 40.
Have. The upper member 32 has an upper wall 42 and a front wall 44
You. The lower member 30 and the upper member 32 are illustrated in FIG.
The developer container 28 is formed by being mutually connected to the cage. Lower
The member 30 is substantially separated from the bottom wall 34 except on both sides thereof.
The separation wall 46 protruding vertically upward is also integrated
The space in the developing container 28 is formed on the separation wall 46.
Therefore, the upstream path 48 (the right side of the separation wall 46 in FIG. 1)
2 and the upper side of the separation wall 46 in FIG.
Path) and the downstream path 50 (the left side of the separation wall 46 in FIG. 1).
, And in FIG.
Road). The upstream path 48
A feeding / stirring mechanism 52 is provided, and the downstream
A side transport / stirring mechanism 54 is provided. Developing container 28
Is also provided with a developer applying means 56. This developer
The application means 56 has a width along the downstream side transport / stirring mechanism 54.
Direction (direction perpendicular to the paper surface in FIG. 1, left direction in FIG. 2)
Rotating sleeve member 58 extending rightward), and a sleeve portion.
And a stationary magnet member 60 disposed in the material 58.
ing. An opening extending in the width direction is provided on the front surface of the developing container 28.
62, the sleeve of the developer applying means 28
Member 58 partially projects forward through such opening 62
The rotating drum in the developing zone 10
2 is close to the peripheral surface. On the developer container 28
The developer restricting member 6 is connected to the side member 32 via a connecting piece 63.
4 is fixed. This developer restricting member 64 is
And is suspended substantially vertically toward the
Around the end of the developer restricting member 64 and the sleeve member 58.
It is about 0.3 to 0.8 mm between the surface and
An advantageous distance d1 is formed. Developing container 28
The toner density is substantially at the center of the rear wall 36 in the width direction.
Detection means 66 is provided. Such toner density detection
The means 66 exposes the detection surface to the upstream path 48.
From the magnetic permeability detector provided.

The developer container 28 contains a developer 68 composed of toner and carrier particles. While the developer 68 is being stirred by the action of the upstream conveying / stirring mechanism 52, the upstream path 48 moves from one end to the other end as shown by an arrow 69 (from the right end to the left end in FIG. 2). 2), and is transferred from the other end (the left end in FIG. 2) of the upstream path 48 to the other end (the left end in FIG. 2) of the downstream path 50. In the downstream path 50, the downstream conveying / stirring mechanism 54 stirs the developer 68 and conveys it from the other end to one end as shown by an arrow 70 (from the left end to the right end in FIG. 2). Then, it is transferred from one end of the downstream path (the right end in FIG. 2) to one end of the upstream path 48 (the right end in FIG. 2).
Thus, the developer 68 is circulated through the upstream path 52 and the downstream path 54, and during this circulation, the toner and the carrier particles are stirred, and the toner is charged to a predetermined characteristic. The configuration and operation of the upstream transport / stirring mechanism 52 and the downstream transport / stirring mechanism 54 will be described later in further detail. The sleeve member 58 of the developer applying means 56 is rotated in the direction indicated by the arrow 71 in FIG. 1 to attract the developer 68 to the peripheral surface in the developer pumping area 72 by the magnetic attraction of the stationary magnet member 60. The developer 68 is transported to the developing area 10 and applied to the electrostatic latent image on the image bearing member 6, and the toner is selectively adhered to the image bearing member 6 and developed into a toner image. The developer restricting member 64 is
The amount of the developer 68 held on the peripheral surface of the sleeve member 58 and carried to the developing area 10 is regulated. When the toner in the developer 68 is consumed in accordance with the development, and the toner concentration in the developer 68 becomes lower than a predetermined value, the toner is supplied into the developing container 28 by the operation of a toner supply unit described later. A toner supply opening 74 shown by a two-dot chain line in FIG. 2 is formed in the upper member 32 of the developing container 28, and toner is supplied to the upstream path 48 through the toner supply opening 74. The toner supply will be described later in more detail.

[0016]Upstream and downstream transport in developing means
Stirring mechanism  Continuing the description with reference to FIG. 1 and FIG.
The stirring mechanism 52 is provided for the lower member 30 of the developing container 28.
It is rotatably mounted between the side walls 38 and 40 and
It has a rotating shaft 76 extending in the path 48. This rotating shaft 7
6 have circular flanges 78 and 80 at both ends.
I have. The rotating shaft 76 has a portion between the circular flanges 78 and 80.
Are also formed. Round
The outer diameters of the flanges 78 and 80 and the spiral blade 82 are substantially
Above may be the same. One end of the spiral blade 82 and the circular flange 78
Is relatively small, but the other end of the spiral blade 82 and
The spacing between the circular flange 80 is relatively large. Spiral wings
The rotating shaft 7 is provided between one end of the root 82 and the circular flange 78.
6 radially from the peripheral surface and from one end of the spiral blade 82
Continuously extends straight in the axial direction up to the circular flange 78
An end paddle piece 84 is formed. Half of end paddle piece 84
The radial leading edge is substantially aligned with the outer peripheral edge of the spiral blade 82.
Position (in other words, the end
The radius of the circular locus drawn by the radial leading edge of the dollar piece 84 is
The radius is substantially the same as the radius of the outer peripheral edge of the turning blade 82). Spiral
Between the other end of the blade 82 and the circular flange 80,
A pair of rotation shafts 76 are arranged at an angle of 180 degrees.
A transfer paddle piece 86 is formed. A pair of transfer paddles
The piece 86 faces the circular flange 80 in FIG.
It extends slightly clockwise as viewed from the side. Pair of
The leading edge of the transfer paddle piece 86 in the radial direction is
Substantially aligned with or slightly inside the outer edge
It is convenient to do so. As clearly shown in FIG.
The circumferential surface of the rotating shaft 76 is radially away from the circumferential surface of the rotating shaft 76.
A substantially rectangular shape extending in the axial direction between the spiral blades 82
Large paddle pieces 88a, 88b, 88c, 88d, 88e and
And 88f are formed. These six large paddle pieces 8
8a, 88b, 88c, 88d, 88e and 88f are actual
It is arranged at the same angular position qualitatively,
Continuously extending straight and their radial leading edges spiral
It is located substantially in alignment with the outer peripheral edge of the blade 82. In addition,
As shown in FIG.
At an angle to the large paddle pieces 88c and 88d
One large paddle piece 88g is also formed.
The large paddle piece 88g also has a substantially rectangular shape and extends between the spiral blades 82.
Continuously extending straight and their radial leading edges spiral
It is located substantially in alignment with the outer peripheral edge of the blade 82. Rotating shaft 7
6 is further radially away from the peripheral surface of the rotating shaft 76.
A substantially rectangular shape extending in the axial direction between the spiral blades 82
A number of small paddle pieces 90 are also formed. Refer to FIG.
As will be appreciated, one half of the rotating shaft 76
(At the right half in FIG. 2)
While small paddle pieces 90 are formed at intervals
And the other half of the rotating shaft 76 (the left half in FIG. 2)
Small paddle pieces 90 are formed at 90 degree intervals
Have been. Therefore, it is formed on one half of the rotating shaft 76.
The number of the small paddle pieces 90 is formed on the other half of the rotary shaft 76.
Half of the number of the small paddle pieces 90 that are provided. Small paddle pieces
Each of 90 does not extend continuously between spiral blades 82
In the axially central region between the spiral blades 82, a pad is provided.
There are no pieces. Also, the small paddle pieces 90 project in the radial direction.
The protruding length is large paddle pieces 88a, 88b, 88c, 88d,
Shorter than the radial projection length of 88e, 88f and 88g
In the radial direction of the small paddle piece 90 from the peripheral surface of the rotating shaft 76.
The radial length up to the leading edge is
Approximately half of the radial length up to the outer peripheral edge of the turning blade 82
Is preferred.

The upstream transport / stirring mechanism 5 as described above
2, the rotating shaft 76 is rotated clockwise as viewed from the right side in FIG. 2, and the spiral blade 82 is stirred in the direction indicated by an arrow 69 while stirring the developer 68 (that is, in the direction from right to left in FIG. 2). ) Transport. Large paddle piece 88
a, 88b, 88c, 88d, 88e, 88f and 88
g and a number of small paddle pieces 90 allow the developer 68 to
6 and the developer 68 by the spiral blade 82
Enhances stirring. In general, when the paddle piece has a longer protruding length in the radial direction, the stirring action of the developer 68 is increased, but the transport action in the direction indicated by the arrow 92 is reduced. In view of such a fact, in the illustrated upstream-side transport / stirring mechanism 52, the radially projecting lengths of the large number of small paddle pieces 90 are set to the large paddle pieces 88a, 88b, 88c, 88.
D, 88e, 88f, and 88g are set to approximately half, so that the conveyance and the stirring of the developer 68 are appropriately coordinated. The number of the small paddle pieces 90 in one half of the rotating shaft 76, that is, the right half in FIG. 2, is half the number of the small paddle pieces 90 in the other half of the rotating shaft 76, that is, the left half in FIG. Due to this, in one half of the rotation shaft 76, particularly in the area where the toner supply opening 74 described above is provided, the upper surface level u1 of the developer 68 is equal to the average upper surface level u2 (in the other half of the rotation shaft 76). (Top level of developer). As a result, the replenishment toner dropped from the toner replenishment opening 74 is sufficiently satisfactorily supplied to the upstream path 48.
Is mixed into the developer 68 existing in the inside. On the other hand, in the area where the toner density detecting means 66 is provided, the upper surface level u3 of the developer 68 is slightly higher than the average upper surface level u2 due to the presence of the large paddles 88c, 88d and 88g. . Thereby, the toner density detecting means 66
Erroneous detection of the toner concentration can be sufficiently and reliably avoided. Further, the following facts should be noted regarding the upstream transport / stirring mechanism 52. That is, many small paddle pieces 90 do not extend continuously between the spiral blades 82 in the axial direction, and no paddle pieces exist in the axially intermediate region between the spiral blades 82, and the small paddle pieces 90 Side edge 92 is formed. Therefore, while the rotation shaft 76 is rotated, the side edge 92 of the small paddle piece 90 exerts a so-called shearing action on the developer 68 in the axially intermediate region between the spiral blades 82, and the shearing action causes The agitation action of 68 is significantly increased. Thus, the upstream path 48
In this case, the developer 68 is transported at a desired transport rate in the direction indicated by the arrow 69, and is sufficiently sufficiently stirred during the transport. The developer 68 transported to the other end (the left end in FIG. 2) of the upstream path 48 is transferred to the downstream path 50 by the action of the pair of transfer pad pieces 86.

Next, the downstream transport / stirring mechanism 54 will be described.
A rotary shaft 94 rotatably mounted between the side walls 38 and 40 of the lower member 30 and extending through the downstream path 50.
Having. Circular flanges 9 are provided at both ends of the rotating shaft 94.
6 and 98 are formed. The rotary screw 94 has a continuous spiral blade 10 disposed between the circular flanges 96 and 98.
0 is also formed. The outer diameters of the circular flanges 96 and 98 and the spiral blade 100 may be substantially the same. Spiral blade 1
While the distance between one end of the spiral blade 100 and the circular flange 98 is relatively small, the distance between the other end of the spiral blade 100 and the circular flange 96 is relatively large. Between one end of the spiral blade 100 and the circular flange 98, a circular flange 98 is provided in a radial direction from the peripheral surface of the rotating shaft 94 and from one end of the spiral blade 100.
End paddle piece 102 extending straight in the axial direction continuously to
Are formed. The radial leading edge of the end paddle piece 102 is positioned substantially in alignment with the outer peripheral edge of the spiral blade 100 (in other words, the rotation of the rotary shaft 94 causes the end paddle piece 1
The radius of the circular locus drawn by the radial leading edge of No. 02 is substantially the same as the radius of the outer peripheral edge of the spiral blade 100). Between the other end of the spiral blade 100 and the circular flange 96, a pair of transfer paddle pieces 104 are formed on the rotating shaft 94 at an angle of 180 degrees. The pair of transfer paddle pieces 104 extend toward the circular flange 96 with a slight inclination in the counter direction as viewed from the right side in FIG. The tip end in the radial direction of the pair of transfer paddle pieces 104 is the spiral blade 1
Conveniently, it is substantially aligned with or slightly inward of the outer periphery of 00. Further, as clearly shown in FIG. 2, a large number of substantially rectangular middle paddle pieces 106 extending radially from the peripheral surface of the rotary shaft 94 and axially between the spiral blades 100 are provided on the peripheral surface of the rotary shaft 94. Are formed. Such middle paddle pieces 106 are arranged substantially uniformly over the entire area of the spiral blade 100. Middle paddle piece 1
Each of the reference numerals 06 is arranged at an angular interval of 90 degrees in the entire axial direction region where the spiral blade 100 is formed, and extends substantially straight between the spiral blades 100 continuously. The radial projection length of each of the middle paddle pieces 106 is
The length in the radial direction of the small paddle piece 90 in the upstream transport / stirring mechanism 52 described above is set to be substantially the same as the radial length from the peripheral surface of the rotating shaft 94 to the radial leading edge of the middle paddle piece 106. The length is substantially half the radial length from the peripheral surface of the rotating shaft 94 to the outer peripheral edge of the spiral blade 100.

Downstream transport / stirring mechanism 5 as described above
4, the rotating shaft 94 is rotated counterclockwise when viewed from the right side in FIG.
2, the spiral blade 100 transports the developer 68 in the direction indicated by the arrow 70 (ie, from left to right in FIG. 2) while stirring the developer 68. The middle paddle piece 106 is the developer 68
Is forced in the rotation direction of the rotation shaft 94 to promote the stirring of the developer 68 by the spiral blade 100. Further, the following facts should be noted regarding the middle paddle piece 106 in the downstream-side transport / stirring mechanism 54. As described above, the sleeve member 58 of the developer applying unit 28 is provided with the developer pumping area 72.
, The developer 68 existing in the downstream path 50 is pumped up and conveyed to the development area 10. Width direction, ie, sleeve member 5
In order to achieve sufficiently uniform development over the entire axial direction of the sleeve 8, it is important that the developer 68 is pumped sufficiently uniformly over the entire peripheral surface of the sleeve member 58 over the entire axial direction. It is important that the developer 68 is sufficiently uniform over substantially the entire end of the downstream path 50. However, the spiral blade 1
When only 00 is formed, the developer 68 drawn on the peripheral surface of the sleeve member 58 tends to generate a spirally extending spot corresponding to the spiral blade 100. According to the experiments of the present inventors, the middle paddle pieces 106 uniformly arranged over the entire spiral blade 100 suppress the occurrence of the above-mentioned unevenness in the developer 68 pumped to the peripheral surface of the sleeve member 58, and It has been confirmed that the developer 68 pumped to the peripheral surface of the member 58 is made uniform. Further, with respect to the middle paddle piece 106, the following facts should be noted. Arrow 6 by the upstream transport / stirring mechanism 52
It is important that the developer transfer operation in the direction indicated by 9 and the developer transfer operation in the direction indicated by arrow 70 by the downstream transfer / stirring mechanism 54 are balanced. otherwise,
The developer 68 is unevenly distributed in the upstream path 48 or the downstream path 50. In the upstream transport / stirring mechanism 52, the large paddle pieces 88a, 88b, 88c, 88d, 88e, and 8 have a large transport suppressing action for the various reasons described above.
8f and 88g, a small paddle piece 90 having a small conveyance suppressing action
Whereas, in the downstream-side transport / stirring mechanism 54, the transport suppressing action has a large paddle piece 88a,
The middle paddle pieces 106 between the small paddle pieces 90 and 88b, 88c, 88d, 88e, 88f, and 88g are evenly arranged over the entire spiral blade 100, and thus the arrow 69 by the upstream conveying / stirring mechanism 52. The developer conveying action in the direction indicated by the arrow and the arrow 7 by the downstream conveying / stirring mechanism 54
This balances the developer transport action in the direction indicated by 0.

[0020]Uniform member in developing means  Continuing the description with reference to FIG.
Connecting piece 63 connected to upper member 32 of developing container 28
Of the sleeve member 58 in the developer applying means 56
Positioned upstream of the developer restricting means 64 when viewed in the rotational direction
The uniformizing member 108 is also fixed. The connecting piece 63
A piece of droop having a droop depending substantially vertically
The developer restricting member 64 is fixed to the surface (the left side in FIG. 1).
The uniformizing member 108 is fixed on the other surface (the right surface in FIG. 1).
Is defined. The uniformizing member 108 is provided with the developer restricting unit 6.
4, along the circumferential surface of the sleeve member 58 in the width direction.
(In the direction perpendicular to the plane of FIG. 1). Uniform
The forming member 108 moves downward in the rotation direction of the sleeve member 58.
Toward the flow side, and thus to the developer restricting member 64
The working surface 1 gradually approaching the peripheral surface of the sleeve member 58
With 10. Downstream edge of such working surface and sleeve member
The distance d2 between the peripheral surface of the developer 58 and the developer restricting member 64 is
It is larger than the distance d1 with the peripheral surface of the leave member 58.
However, in the developer pumping area 72, the sleeve member 58
Layer thickness of developer 68 pumped and held on the peripheral surface
It is important that the value is set smaller than
It is preferable that it is about 3.0 to 3.0 mm. Developer restrictions
Connecting piece 6 located between member 64 and homogenizing member 108
The lower edge of the hanging part of the third unit 3 is the working surface 11 of the equalizing member 108.
0 is substantially aligned with the downstream edge. Uniformization section
The working surface of the member 108 is an even surface of the peripheral surface of the sleeve member 58.
Portion where the downstream edge of the working surface 110 of the monolithic member 108 faces
Tangent at the position (in the illustrated embodiment such tangent is
20 to 30 degrees to extend substantially horizontally)
Are extended at an appropriate inclination angle α.
You.

As described above, the downstream transport / stirring mechanism 54
In, the spiral blade 100 is formed on the peripheral surface of the rotating shaft 94, and the middle paddle piece 106 is disposed over the entire area of the spiral blade 100. Therefore, the layer thickness of the developer 68 which is pumped and held on the peripheral surface of the sleeve member 58 in the developer pumping area 72 is relatively uniform in the width direction, but the uniformity is not sufficient. Not
There is some non-uniformity due to the presence of the spiral blade 100. According to experiments performed by the present inventors, when the uniforming member 108 is not provided, the unevenness in the layer of the developer 68 held on the peripheral surface of the sleeve member 58 is caused by the developer limiting member 64. However, some unevenness tends to remain in the layer of the developer 68 conveyed to the developing area 10, but when the equalizing member 108 is provided, the unevenness is retained on the peripheral surface of the sleeve member 58. First, the homogenizing member 108 acts on the developer 68 to make it uniform in the width direction, and thereafter, the developer restricting member 64 acts to develop the developer 6.
It has been found that the thickness of the layer 8 is limited as required, and that the developer 68 held on the peripheral surface of the sleeve member 58 is sufficiently uniform in the width direction to have a predetermined thickness.

[0022]Seal member in developing means  Referring to FIG. 3 together with FIG.
Each of the side walls 38 and 40 of the lower member 30 includes
Both ends of sleeve member 58 in developer applying means 56
The stationary sealing members 112 and 114 are brought into close contact with each other.
It is arranged. It is good to be formed from felt
Each of the mating seal members 112 and 114 is
As will be clearly understood from FIG.
Along an arc of approximately 200 degrees
The downstream end of the sleeve member 58 is upward when viewed in the rotational direction.
Located close to and upstream of the developer restricting member 64,
The upstream end is the lowermost end on the peripheral surface of the sleeve member 58.
It is located somewhat upstream. Figure 3 clearly shows
As shown, the sealing members 112 and 114
Downstream edges 116 and 118 are substantially
It extends horizontally. However, the sealing members 112 and
And the upstream edges 120 and 122 of the
Portion extends substantially horizontally, but the widthwise inner half
In the part, incline in the downstream direction toward the width direction inside
Extending.

The seal members 112 and 114 are provided along the peripheral surface of the sleeve member 58 of the developer applying means 56.
The developer 68 is prevented from moving to both ends. However, the sealing members 112 and 114 are arc-shaped,
Downstream edges 116 and 11 of seal members 112 and 114
8 to the upstream edges 120 and 122 (in most of the range, the peripheral surface of the sleeve member 58 is exposed from the developing container 28 through the opening 62), and there is no seal member. When the developer 68 held on the peripheral surface of the sleeve member 58 passes through the above-described range, an arrow 7
When moved in the direction indicated by 1, the developer 68 tends to flow somewhat to both sides in the width direction beyond the regulation edge defined by the inner edges of the sealing members 112 and 114. In the conventional sealing member, since not only the downstream edge but also the upstream edge thereof extends substantially horizontally over the entire width direction, the developer 68 flowing on both sides in the width direction beyond the regulating end is used. It tends to stay on the upstream edge of the seal member and scatter around when the stay becomes excessive. However, in the seal members 112 and 114, the widthwise inner halves of the upstream edges 120 and 122 are inclined inward in the widthwise direction toward the downstream side. The developer 68 which has flowed to both sides in the direction moves in the direction indicated by the arrow 71 in accordance with the rotation of the sleeve member 58 when the seal member 112 is moved.
And 114 are guided back to the widthwise inside by the inclined inner halves of the upstream edges 120 and 122, and thus, excessive developer 68 may stay on the upstream edges 120 and 122 of the seal members 112 and 114. Effectively prevented.

[0024]Toner supply means in developing means  Describing with reference to FIG.
A toner supply means 124 is also included. This toner
The replenishing means 124 is for assembling a plurality of synthetic resin members.
With a housing structure 126 formed by
are doing. The housing structure 126 has a relatively lower half
128 and a relatively high other half 130. Such c
The mixing structure 132 and the recycle
Toner receiving chamber 134, toner carry-in path 136, and recycling
A toner feeding path 138 is defined. 4 and
Referring to FIGS. 5 and 6, the mixing chamber 132
A corner portion of the housing structure 126 (right portion in FIG. 5, FIG.
6 in the upper right), more specifically the housing structure
126 is arranged on one side of one half 128 of
One side (the left side in FIG. 5, the lower side in FIG. 6),
The upper surface and the front surface (the left surface in FIG. 6) are open.
The recycled toner receiving chamber 134 is provided in the housing structure 12.
6, the diagonal to the corner where the mixing chamber 132 is located
To the corner formed, more specifically to the other side of the other half 130
Are located. This recycled toner receiving chamber 134
Is the relatively high other half 130 of the housing structure 124.
From the receiving opening 140 formed in the upper surface of the
Is extended downward, and one end face of the lower part (see FIG.
4 is open. Toner loading path 13
6 in FIG. 6 from the open front of the mixing chamber 132
To the right, then upward, and further to the developer container 28
It is extended toward the upper surface. Such toner transport
The upstream end of the entrance 136 is recycled by the partition 142
Toner feeding path 138 and recycled toner receiving chamber 1
34, and the middle and downstream sections are appropriately curved
The cross-sectional shape extending is defined by the circular hollow part
I have. Then, on the lower surface of the downstream portion of the toner carrying path 136,
Is formed on the upper member 32 of the developing container 28 described above.
The toner supply opening 74 (FIG. 2)
A horn discharge opening (not shown) is formed. Re
The cycle toner feeding path 138 includes a housing structure.
The other half of the one half 128 of FIG.
Lower side) above the recycled toner receiving chamber 134
It extends from one open end face to the right in FIG.
You. As clearly shown in FIG. 4 and FIG.
At the downstream portion (right portion in FIG. 6) of the feeder feeding path 138.
In this case, the partition 142 is omitted, and
One side surface at the downstream portion of the toner feeding path 138 (FIG. 5)
The right side in FIG. 6 and the upper side in FIG.
It is in direct communication with the released one side.

As shown by a two-dot chain line in FIGS. 4 and 6,
Above the mixing chamber 132 defined in the other half 130 of the housing structure 126, the toner cartridge 14
4 is detachably mounted. The toner cartridge 144 itself constituting the new toner container may be of a known type, and a toner outlet is formed at the lower end of the toner cartridge 144.
2 and communicates with the open top surface. Therefore, the new toner contained in the toner cartridge 144 is dropped through the toner outlet of the toner cartridge 144 and the open upper surface of the mixing chamber 132 and is supplied into the mixing chamber 132.

Continuing the description with reference to FIG. 1 in conjunction with FIG.
Is the cleaning container 146, the cleaning blade 1
48, cleaning roller 150 and toner conveying means 1
52. An auxiliary blade 156 is provided on the cleaning roller 150 which is rotationally driven in a direction indicated by an arrow 154.
Is attached. The tip of the cleaning blade 148 is pressed against the surface of the image bearing member 6, and the residual toner on the image bearing member 6 rotated in the direction indicated by the arrow 4 is removed by the action of the cleaning blade 148, and is left on the cleaning roller 148. It is dropped. The cleaning roller 150 carries the toner dropped on the surface of the image bearing member 6 by the action of the cleaning blade 148 along with the toner removed from the surface of the image bearing member 6 in the direction indicated by the arrow 154 while holding the toner on the peripheral surface. And
The arrow 1 held on the peripheral surface of the cleaning roller 150
The toner carried in the direction indicated by 54 is the auxiliary blade 156.
Is removed from the peripheral surface of the cleaning roller 150 and collected on one side (the left side in FIG. 1) of the cleaning container 150. The toner conveying means 152
Is constituted by a rotating shaft extending in one side of the cleaning container 146 in a width direction (a direction perpendicular to the paper surface in FIG. 1) and a spiral blade disposed on a peripheral surface of the rotating shaft. The toner conveying means 152 is driven to rotate in the direction indicated by the arrow 158, and conveys the toner collected on one side of the cleaning container 146 forward in FIG. As shown in FIG.
Is disposed in relation to the front of the cleaning container 146. The toner recycling means 26 includes a hollow member 160 in which a toner recycling path is formed. This hollow member 160 is used for the cleaning container 1.
Inclined rising portion 162 extending upward from the front of 46
And the hanging portion 16 extending downward from the inclined rising portion 162
And 4. The lower end of the inclined rising portion 162 is communicated with the cleaning container 146, and the lower end of the hanging portion 164 is communicated with the receiving opening 140 of the recycled toner receiving chamber 134. Hollow member 160
Of the recycled toner conveying means 1
66 are provided. The recycled toner conveying means 166 is composed of a rotating shaft extending inside the inclined rising portion 162 and a spiral blade disposed on the peripheral surface of the rotating shaft. The recycled toner conveying means 166 is the arrow 1
It is driven to rotate in the direction indicated by 68.

In the cleaning area 14, the cleaning blade 148 and the cleaning roller 150 remove the toner from the image bearing member 6 and remove the cleaning container 146.
The toner collected on one side (left side in FIG. 1) of
The toner is transported to the front of the cleaning container 146 by the operation of the toner transporting unit 152, and the toner is recycled by the toner recycling unit 26.
At the upstream end of the hollow member 160, ie, the inclined rising portion 16
2 to the lower end. Next, the inside of the inclined rising portion 162 of the hollow member 160 is raised from its lower end toward its upper end by the action of the recycled toner conveying means 166, and then the hanging portion 164 of the hollow member 160 is moved from the upper end of the inclined rising portion 162. Through the receiving opening 140 and the recycled toner receiving chamber 1
34.

Referring again to FIG. 4 and FIGS. 5 and 6, the recycled toner accommodated in the recycled toner receiving chamber 134 is supplied to the recycled toner receiving chamber 134 and the recycled toner feeding path 138 described above. Mixing chamber 132 through feed path 138
Toner feeding means 170 for feeding toner
Are arranged. The recycled toner feeding means 170 has a rotating shaft 172 extending through the bottom of the recycled toner receiving chamber 134 and the recycled toner feeding path 138. A spiral blade 174 is provided on the peripheral surface of the rotating shaft 172 that is driven to rotate in the direction indicated by the arrow 173. The spiral blade 174 does not extend to the downstream portion of the rotation shaft (the right end portion in FIG. 6 and the portion extending along the open one side surface of the mixing chamber 132). An end disk 176 is formed at the downstream end (right end in FIG. 6) of the rotating shaft 172, and a paddle piece 178 is formed between the end disk 176 and the downstream end of the spiral blade 174. . As can be easily understood by referring to FIGS. 5 and 6, the paddle piece 178 has a rectangular shape and extends radially from the peripheral surface of the rotating shaft 172 and the rotating shaft 1.
72 extends in the axial direction on the peripheral surface.

The description will be continued with reference to FIGS.
A toner carrying means 180 is provided in the mixing chamber 132 and the toner carrying path 136. This toner carrying means 180
Is constituted by a spiral spring extending through the bottom of the mixing chamber 132 and the toner carrying path 136. The spiral spring constituting the toner carrying means 180 is preferably formed by spirally forming a rectangular steel wire having a cross section other than a circular shape. As shown in FIGS. 4 and 6, an electric motor 182 for supplying toner is mounted on an outer surface of a rear wall (right wall in FIG. 6) of the mixing chamber 132, and an output shaft of the electric motor 182 for supplying toner is It penetrates the rear wall and protrudes into the mixing chamber 132. One end of the toner carrying means 180 is connected to the output shaft.
When the toner replenishing electric motor 182 is energized, the toner carrying means 180 is rotated in the direction shown by the arrow 184, and the toner is supplied from the mixing chamber 132 to the developing container 28 (FIGS. 1 and 2) through the toner carrying path 136. Replenished. The supply of the toner to the developing container 28 will be further described later.

The toner conveying means 152 in the cleaning means 24, the recycled toner conveying means 166 in the toner recycling means 26, and the toner feeding means 170 provided in the recycled toner feeding path 138 are each provided with an appropriate transmission means ( (Not shown) is connected to a main electric motor 186 (FIG. 7) for rotating the rotary drum 2 (the developing means 2).
The upstream conveying / stirring mechanism 52 and the downstream conveying / stirring mechanism 54 disposed in the developing container 28 at 0 can also be connected to the main electric motor 186 via appropriate transmission means). Therefore, the main electric motor 186 is energized,
When the rotating drum 2 is being rotated in the direction indicated by the arrow 4, the rotating drum 2 is disposed in the toner transporting unit 152 in the cleaning unit 24, the recycled toner transporting unit 166 in the toner recycling unit 26, and the recycled toner feeding path 138. Each of the supplied toner feeding means 170 is also operated. Thus, the toner removed from the surface of the image bearing member 6 disposed on the peripheral surface of the rotating drum 2 in the cleaning area 14 is stored in the recycled toner receiving chamber 134 from the cleaning means 24 through the toner recycling means, and furthermore, Toner feed path 1 from recycled toner receiving chamber 134
38 to the mixing chamber 132,
Is mixed with fresh toner supplied from the toner cartridge 144 to the mixing chamber 132.

The capacity of the recycled toner receiving chamber 134 in the toner replenishing means 124 is set to about 20% of the capacity of the toner cartridge constituting the new toner storing means. More specifically, if the capacity of the recycled toner receiving chamber 134 is excessively small, the following problem occurs. For example, in a normal electrostatic copying machine, when a copy process of forming a copy image of a small document on a small sheet member is repeatedly performed many times in a state where the document cover is kept in an open position, or when a sheet member is to be jammed. If a large amount of toner is moved at one time in the cleaning unit 24 and / or the toner recycling unit 26 due to a considerable physical impact applied to the cleaning unit 24 and / or the toner recycling unit 26, the recycled toner is received. Room 134
In some cases, a large amount of recycled toner may be temporarily supplied. In such a case, the recycled toner receiving room 1
If the capacity of 34 is excessively small, there is a possibility that the recycled toner overflows from the recycled toner receiving chamber 134 and scatters around. On the other hand, if the recycled toner receiving chamber 134 is set to be excessively large, the toner
4 becomes bulky. As will be further described later, the operation of the toner replenishing electric motor 182 in the toner replenishing means 124 in accordance with the toner concentration in the developer 68 in the developing container 28, that is, from the mixing chamber 132 to the developing container 28
The supply of toner to the developing container 28 is controlled, so that the amount of toner in the developing container 28 is maintained at a substantially constant amount. On the other hand, as is well known to those skilled in the art, the transfer efficiency in a normal image forming machine is about 80.
% Of the toner adhered on the image bearing member 6.
0% is transferred to the sheet member in the transfer area 12, and the remaining 20% is removed from the image bearing member 6 in the cleaning 14. Generally, at the start of use of the image forming apparatus, a predetermined amount of toner is previously filled in the developing container 28 together with carrier particles, and thereafter, the developer 68 in the developing container 28 is filled.
In accordance with the consumption of the toner inside, the toner cartridge 144 newly attached to the toner replenishing means 124 is used for the mixing chamber 1.
The toner supplied to the developer container 32 is supplied to the developing container 28.
Therefore, the theoretical maximum value of the toner existing in the cleaning unit 24, the toner recycling unit 26, and the recycled toner receiving chamber 134 is the
4, which is 20% of the capacity of the toner cartridge 144. Therefore, even if substantially all of the toner in the cleaning unit 24 and the toner recycling unit 26 is supplied to the recycled toner receiving chamber 134 due to a special situation, the theoretical maximum amount of the recycled toner to be stored in the recycled toner receiving chamber 134 is considered. The large amount is approximately 20% of the capacity of the toner cartridge 144. Since the capacity of the recycle toner receiving chamber 134 is approximately equal to the capacity of the toner cartridge 144,
If it is set to 0%, it is possible to reliably avoid the possibility that the recycled toner overflows from the recycled toner receiving chamber 134 and scatters around without increasing the capacity of the recycled toner receiving chamber 134 excessively.

In the above-described toner replenishing means 124, the following facts should be noted. Mixing room 1
At 32, new toner is dropped from the toner cartridge 144 through the open top surface,
Recycled toner is fed through the opened one side. Due to a unique supply style such as new toner and recycled toner to the mixing chamber 132, the mixing chamber 13
It has been found that the new toner and the recycled toner can be mixed sufficiently well within 2. In addition, sending the recycled toner to the mixing chamber 132
This is effected effectively by the action of the paddle pieces 178 which are rotated in the direction indicated by the arrow 173 and thus from the bottom to the upper side on the side of the mixing chamber 132 facing the open one side, which also results in fresh toner and Mixing with recycled toner is promoted. The rotation shaft 172 on which the paddle piece 178 is formed is rotated in the direction opposite to the direction shown by the arrow 173 (in this case, the rotation shaft 172
It is necessary to reverse the direction of the spiral blades 174 formed on the paddle.) However, according to experiments by the present inventors, it is more preferable to rotate the paddle piece 178 in the direction indicated by the arrow 173. It has been found to be suitable both in terms of feeding the recycled toner into the mixing chamber 132 and mixing new and recycled toner in the mixing chamber 132.

[0033]Toner supply control  As already mentioned with reference to FIGS. 2 and 4, the developing means
Reference numeral 20 denotes the toner concentration in the developer 68 in the developing container 28.
(That is, the weight TW of the toner with respect to the weight DW of the developer 68)
Density detecting means 66 for detecting the ratio TW / DW)
Are arranged. The toner density detecting unit 66 includes:
The output voltage changes according to the toner concentration in the developer 68.
More specifically, the toner concentration in the developer 68 decreases.
And the output voltage rises, a permeability detector known per se
It is composed of It consists of a microcomputer
The toner supply control means 188 (FIG. 7)
The toner density detected by the toner density detecting means 66, that is,
Developing container 2 based on the output voltage of toner concentration detecting means 66.
8, the toner replenishing means 12
4 controls the operation of the toner supply electric motor 182.

Referring to the flow chart shown in FIG. 8, in step N-1, the rotating drum 2, the upstream conveying / stirring mechanism 52, the downstream conveying / stirring mechanism 54 in the developing means 20, and the recycled toner feeding means 170, it is determined whether or not a predetermined time (for example, 5 seconds) has elapsed since the main electric motor 184 for driving the toner conveying unit 152 in the cleaning unit 24 and the recycled toner conveying unit 166 in the toner recycling unit 26 is energized. Is determined. When a predetermined time has elapsed since the main electric motor 184 was energized, the process proceeds to step N-2. That is, when the main electric motor 184 is deenergized, toner replenishment is not performed, and the toner replenishment control is started only after a predetermined time has elapsed since the main electric motor 184 was energized. In step N-2, it is determined whether or not the toner density detected by the toner density detecting means 66 is equal to or lower than a predetermined lower limit toner density value (this lower limit toner density value will be further described later). It is determined whether the voltage is equal to or higher than a predetermined upper limit voltage value set by upper limit voltage value setting means 190). If the toner density exceeds the lower limit toner density value, the process proceeds to step N-3, and it is determined whether the toner density detected by the toner density detecting means 66 is equal to or less than a predetermined threshold (for example, 3.5%) It is determined whether the output voltage of the density detecting means 66 is equal to or higher than a predetermined voltage threshold set by the voltage threshold setting means 192). If the toner density exceeds the threshold value, the process proceeds to step N-4. When the toner replenishing electric motor 182 is in the operating state, the toner replenishing motor 182 is deactivated, so that the developing container 28 is replenished with toner. Never. If the toner density is equal to or less than the threshold value in step N-3, the process proceeds to step N-5, where the toner supply electric motor 182 is set to the normal operation state. In this normal operation state, until the toner concentration detected by the toner concentration detecting means 66 exceeds the threshold value, the toner supply electric motor 182 sets the normal supply time T1 (for example, 1 second) at the normal supply interval T2 (for example, 1 second). ), The toner supply means 180 is operated to supply toner from the mixing chamber 132 to the developing container 28.

For example, due to the fact that an image having a relatively large so-called solid black portion is continuously developed many times, the toner concentration in the developer 68 in the developing container 28 sharply decreases,
When the toner density is equal to or lower than the lower limit toner density (for example, 2.5%) in step N-2, the process proceeds to step N-6. Then, in step N-6, the toner supply electric motor 182 is continuously operated, and during that time, the start of a new image forming process is prohibited. In this continuous operation, a predetermined continuous supply time T3 (for example, 2
The toner replenishing electric motor 182 is continuously energized for only one minute), so that the toner carry-in means 180 is continuously operated, and the toner is continuously supplied from the mixing chamber 132 to the developing container 28. Then, proceed to Step N-7,
It is determined whether or not the toner density detected by the toner density detecting means 66 is equal to or less than the threshold. If the toner density exceeds the threshold, the toner control routine ends. If the toner density is lower than the threshold, the process proceeds to step N-8.
In step N-8, it is determined whether or not the toner density detected by the toner density detecting means 66 is lower than a predetermined toner density value (for example, 3.2%) which is higher than the lower limit toner density value but lower than the threshold value. (Therefore, it is determined whether the output voltage of the toner density detecting unit 66 is equal to or higher than a predetermined determination voltage value set by the determination voltage value setting unit 194). If the toner density exceeds the judgment toner density value, the process proceeds to step N-9.
, The electric motor 182 for toner replenishment is set in an excessive supply state. In this oversupply state, the toner replenishing electric motor 182 keeps the oversupply interval T5 until the toner concentration detected by the toner concentration detection means 66 exceeds the threshold.
(For example, one second), the toner is repeatedly urged for an excessive supply time (for example, two seconds).
0 is activated, and the toner is supplied to the developing container 28. The excess supply interval T5 is shorter than the normal supply interval T2, and / or the excess supply time T4 is longer than the normal supply time T1, and it is important that toner is replenished in an excessive supply state more than in the normal supply state. It is. Due to the fact that the consumption of toner progresses and there is not a sufficient amount of toner in the mixing chamber 132 and no toner is replenished in the developing container 28 even when the electric motor 182 for replenishing toner is energized, In N-8, the toner density detecting means 6
If the detected toner density is equal to or lower than the determined toner density, the process proceeds to step N-10. This step N-1
At 0, the execution of the continuous image forming process is prohibited (performance of the image forming process is allowed each time), and
A warning signal is generated, a warning lamp is lit, and the user is prone to toner depletion (hence, a need to replace toner cartridge 144 with a new one). Next, the process proceeds to step N-11, where it is determined whether or not the toner cartridge 144 has been replaced. If a signal generated by the replacement operation of the toner cartridge 144 is detected, the toner supply control routine ends.

Regarding the toner supply control as described above, the following facts should be noted. In the conventional toner supply control, steps N-8 and N-9 are not employed, and if the toner density is equal to or less than the threshold in step N-7, the process directly proceeds to step N-10. . In such a case, when there is sufficient toner in the mixing chamber 132, it is necessary to make the toner concentration exceed the threshold value by the continuous supply performed in step N-6, and thus the continuous supply time T3 is reduced. It needs to be set relatively long. In other words, the so-called waiting time during which the start of a new image forming process is prohibited is relatively long. On the other hand, when Steps N-8 and N-9 are adopted, the continuous supply time T3 in Step N-6 is set to a value shorter than the time required to return the toner concentration to the threshold. It is possible to set the time required to return to the determined toner density value lower than the threshold value, so that the so-called waiting time during which the start of a new image forming process is prohibited can be made relatively short.
The determination toner density is not the optimum toner density, but can be set to a density at which development can be performed without causing any particular trouble. If it is determined in step N-8 that the toner density exceeds the determined toner density, the start of a new image forming process is permitted. Then, in step N-9, the toner is replenished to the developing container 28 in excess of the normal case, and the toner concentration of the developer 68 in the developing container 28 is quickly returned to the threshold.

[0037]Compensation of toner supply control threshold  In the illustrated image forming machine, the cleaning area 14
The toner removed from the image bearing member 6
Recycled to zero and reused. Such a toner
When the cycle style is adopted, as already mentioned,
Depending on the performance of the image forming process, it is present in the developing container 28.
The ratio of the recycled toner in the toner in the developer 68 is
When it increases, the output of the toner density detecting means 66 and the actual
It has been found that the relationship with the toner concentration varies.

An example of a change in the relationship between the output of the toner density detecting means 66 and the actual toner density will be described. FIG. 9 shows a product name "DC-2256" from Mita Kogyo Co., Ltd.
4 shows the results of an experiment performed using an electrostatic copying machine sold as "E". The developer used is a developer sold under the trade name "DC-2556 developer" by Mita Kogyo Co., Ltd., and is composed of carrier particles having an average particle size of 105 μm formed of a ferrite material and styrene acrylic material. And a formed toner having an average particle size of 10 μm. As the toner concentration detecting means, a magnetic permeability detector sold by Hitachi Metals, Ltd. under the trade name "5-046A" was used. The abscissa in FIG. 9 indicates the number of sheet members onto which the toner image on the image bearing member 6 has been transferred (accordingly, the number of times the image forming process has been performed), and the ordinate indicates toner supply control with 3V as a voltage threshold (accordingly, magnetic permeability). 4 shows the actual toner concentration of the developer in the developing container when the toner supply is controlled so that the output voltage of the detector becomes 3 V). The actual toner concentration in the developer was determined by extracting a required amount of the developer from the developing container and measuring the toner concentration in the extracted developer. A line A in FIG. 9 indicates a one-time copying process in which one copy of an average document of A4 size is generated when the copying machine is used in an average use mode of a normal copying machine, and a copy of an average document of A4 size. Are shown, the results of an experiment when a three-sheet continuous copying process of continuously forming three sheets are repeated. A line B in FIG. 9 is an experimental result when only a continuous copying process of continuously copying without interrupting a copy of an average A4 size original is performed. A line C in FIG. 9 is a line C in FIG. This is an experimental result when only a single-shot copying process of generating a copy of an average document for each sheet is repeatedly performed.

As can be understood from FIG. 9, when the copying machine is used in the average use mode, the actual toner density with respect to the predetermined output voltage value (3 V) of the magnetic permeability detector constituting the toner density detecting means is copied. It will be appreciated that as the process is performed, and thus as the proportion of resilient toner in the toner in the developer increases, it will increase progressively. When only the continuous copying process is performed, the increase in the actual toner concentration with respect to the predetermined output voltage value (3 V) of the magnetic permeability detector is relatively gradual. However, when only the single copying process is performed,
The increase in the actual toner concentration with respect to the predetermined output voltage value (3 V) of the magnetic permeability detector is extremely sharp. The present inventors presume the reason for such a difference in the increase in the toner density as follows. When the one-shot copying process is repeatedly performed, the rotation time of the rotary drum other than during the actual image forming process, that is, the cumulative time of the so-called idle rotation of the rotary drum becomes longer, and even in such idle rotation, the developing area is not used. Some toner deposits on the image bearing member, such toner is removed from the image bearing member in the cleaning zone and recycled to the developing means. Therefore, when the one-shot copying process is repeatedly performed, the amount of recycled toner is large with respect to the number of copies to be produced, and as a result, the actual toner concentration is increased with respect to the predetermined output voltage value (3 V) of the magnetic permeability detector. It is presumed to be extremely sharp.

FIG. 10 is a graph showing the relationship between the output voltage of the magnetic permeability detector and the toner concentration in the developer. The solid line indicates that the toner in the developer is all new toner and contains recycled toner. The above relationship is shown when there are no copies, and the broken line shows the relationship after 10,000 copies have been generated in the above average usage pattern.

In view of the above facts confirmed by the experiments of the present inventors, the output voltage of the magnetic permeability detector constituting the toner density detecting means 66 and the predetermined voltage threshold value are simply determined without performing any special compensation. When the toner replenishment is controlled on the basis of the image forming process, the number of times the image forming process is performed is increased.
The actual toner concentration of the developer 68 contained in the inside 8 gradually increases. If the actual toner concentration of the developer 68 is excessively increased from the required value, the charging of the toner becomes insufficient, so that the toner adsorbability to the carrier particles is reduced. Problems such as toner scattering and generation of so-called fog (toner adhesion to non-image portions) in a toner image occur.

Therefore, in the present invention, the threshold value used for the toner supply control is appropriately changed according to the performance of the image forming process. As understood from FIG. 9, when the toner density detecting means 66 is constituted by a magnetic permeability detector, it is understood that the output voltage of the toner density detecting means 66 for a predetermined toner density gradually increases as the image forming process is performed. Is done. Therefore, as the image forming process is performed, the voltage threshold set by the voltage threshold setting unit 192 (FIG. 7) is gradually increased. Such an increase in the voltage threshold is theoretically such that the actual toner concentration of the developer 68 in the developing container 28 is maintained substantially constant regardless of the number of image forming steps as shown by the line D in FIG. It is hoped that it is fake. Alternatively, in consideration of the fact that the recycled toner has a lower chargeability than the new toner, and thus the chargeability of the toner decreases as the ratio of the recycled toner increases, the number of times of performing the image forming process is reduced as shown by a line E in FIG. For example, when the number of times exceeds 6,000, the actual toner concentration of the developer 68 in the developing container 28 gradually decreases as the image forming process is performed, so that the chargeability of the toner is maintained substantially constant. The voltage threshold can be increased.

According to experiments by the present inventors, when a copying machine is used in an average usage mode of a normal copying machine (in the case indicated by line A in FIG. 9), a sheet member onto which a toner image has been transferred is used. It has been found that no problem generally occurs even if the voltage threshold is not increased until the number of sheets (the number of times the image forming process is performed) reaches a specific number, for example, about 6000 sheets. Therefore, from the viewpoint of ease of control and the like, for example, the count value of the counting means 196 (FIG. 7) for counting the number of sheet members onto which the toner image has been transferred is a predetermined value, for example, 600.
The voltage threshold is kept constant until reaching 0, and the counting means 19
When the count value of 6 exceeds a predetermined value, the voltage threshold can be increased by a predetermined value each time the count value increases by a predetermined number, for example, 100. The degree of increase in the voltage threshold can be determined experimentally and / or empirically. The counting means 196 includes:
For example, the count value is added each time a sheet member detector disposed near the outlet of the housing of the image forming machine detects a sheet member discharged through the outlet. As mentioned with reference to the lines A, B and C shown in FIG. 9, the relationship between the number of sheet members on which the toner image has been transferred and the variation in the toner density depends on the manner of performing the copying process in the copying machine (ie, single shot). The ratio of the performance of the copying process to the performance of the continuous copying process). Therefore, when it is expected that the use mode of the copying machine is not always average, in order to avoid or suppress the occurrence of an error due to the variation due to the manner of performing the copying process, the rotating drum 2 (accordingly, The increase of the voltage threshold can also be controlled based on the operation time of the main electric motor 186 (FIG. 7) for driving the image bearing member 6) disposed on the surface. In this case, for example,
The time value of the time counting means 198 (FIG. 7) for counting the accumulated operation time of the main electric motor 186 is a specific time, for example, 6 hours (the time required is 60 in an average use mode in a medium-speed copying machine).
The voltage threshold is maintained constant until the time of the cumulative operation time of the main electric motor 186 required for transferring the toner image to the 00 A4 size sheet members is reached. When the time is exceeded, the voltage threshold can be increased by a predetermined value every time the time value increases by a predetermined time, for example, 10 minutes.

Further, if desired, the voltage threshold setting means 19
2 as well as the upper limit voltage value set by the upper limit voltage setting means 109 and the judgment voltage value set by the judgment voltage setting means 194, the count value of the counting means 196 or the counting time of the counting means 198. It can be varied appropriately based on the value.

[0045]

According to the image forming apparatus of the present invention, in addition to the fact that the developer is sufficiently satisfactorily conveyed through the upstream path and the downstream path provided in the developing container of the developing means, particularly, In the upstream path, the developer is sufficiently agitated so that the toner and the carrier particles are mixed sufficiently uniformly and the toner is sufficiently charged, and / or especially in the downstream path, the downstream path The developer is sufficiently uniformly distributed over the entire surface.

[Brief description of the drawings]

FIG. 1 is a simplified cross-sectional view showing a main part of a preferred embodiment of an image forming machine constituted according to the present invention.

FIG. 2 is a partially cutaway plan view showing a developing container, a developer applying unit, an upstream conveying / stirring mechanism, and a downstream conveying / stirring mechanism in a developing unit provided in the image forming machine shown in FIG. FIG.

3 is a partial perspective view showing a seal member in a developing device provided in the image forming machine shown in FIG.

FIG. 4 is a partial perspective view showing a toner replenishing unit, a part of a cleaning unit, and a toner recycling unit of the developing device in the image forming machine shown in FIG.

FIG. 5 is a partial cross-sectional view showing a part of the toner supply unit shown in FIG.

FIG. 6 is a partial cross-sectional view showing a part of the toner supply unit shown in FIG.

FIG. 7 is a block diagram showing control-related elements provided in the image forming apparatus shown in FIG. 1;

FIG. 8 is a flowchart for describing toner supply control in the image forming apparatus shown in FIG. 1;

FIG. 9 is a diagram illustrating a relationship between the number of sheet members onto which a toner image has been transferred and a toner density detected by a toner density detecting unit including a magnetic permeability detector.

FIG. 10 is a diagram illustrating a relationship between an output voltage of a toner density detecting unit formed from a magnetic permeability detector and a toner density;

[Explanation of symbols]

 2: rotating drum 6: image bearing member 8: electrostatic latent image forming area 10: developing area 12: transfer area 14: cleaning area 20: developing means 24: cleaning means 26: toner recycling means 28: developing container 48: upstream side Route 50: Downstream route 52: Upstream transport / stirring mechanism 54: Downstream wheel transport / stirring mechanism 56: Developer applying means 58: Sleeve member 64: Developer limiting member 66: Toner density detecting means 68: Developer 72: Developer pumping area 76: Rotary shaft of upstream conveyance / stirring mechanism 82: Spiral blade of upstream conveyance / stirring mechanism 88a: Large paddle piece of upstream conveyance / stirring mechanism 88b: Large paddle piece of upstream conveyance / stirring mechanism 88c: Large paddle piece of the upstream transport / stirring mechanism 88d: Large paddle piece of the upstream transport / stirring mechanism 88e: Large paddle piece of the upstream transport / stirring mechanism 88f: Upstream Large paddle piece 88g of the transport / stirring mechanism Large paddle piece 90g of the upstream transport / stirring mechanism 90: Small paddle piece 90% of the upstream transporting / stirring mechanism 94: Rotating shaft of the downstream transporting / stirring mechanism 100: Downstream transporting / stirring Spiral blade of the mechanism 106: Middle paddle piece on the downstream-side transport / stirring mechanism 108: Uniform member 110: Working surface of the uniform member 112: Seal member 114: Seal member 120: Upstream edge of the seal member 122: Seal member Upstream edge 124: Toner supply means 132: Mixing chamber 134: Recycled toner receiving chamber 136: Toner carry-in path 138: Recycled toner supply path 144: Toner cartridge 170: Recycled toner supply means 172: Rotating shaft of recycled toner supply means 174: Spiral blade of recycled toner sending means 178: Recycled toner feed Write means paddles 182: toner dispensing motor 184: main electric motor 188: toner supply control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) (31) Priority Claim Number Japanese Patent Application No. 6-3127 (32) Priority Date January 17, 1994 (1994) 3.1.17) (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 6-3128 (32) Priority date January 17, 1994 (Jan. 17, 1994) (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 6-3129 (32) Priority date January 17, 1994 (Jan. 17, 1994) (33) Priority claiming country Japan ( JP) (31) Priority claim number Japanese Patent Application No. 6-3130 (32) Priority date January 17, 1994 (Jan. 17, 1994) (33) Priority claim country Japan (JP) (31) Priority Claim No. Hei 6-3131 (32) Priority date January 17, 1994 (Jan. 17, 1994) (33) Priority claim country Japan (JP) (31) Priority claim no. 42382 (32) Priority Date March 14, 1994 (March 14, 1994) (33) Priority Country Japan (JP) (72) Inventor Tetsuro Kawashima 1-2-28 Tamazo, Chuo-ku, Osaka City Inside Kyocera Mita Corporation

Claims (10)

[Claims] An image bearing means, an electrostatic latent image forming means for forming an electrostatic latent image on the image bearing means, and a developing means for developing the electrostatic latent image on the image bearing means into a toner image Developing means;
Transfer means for transferring the toner image on the image carrying means onto a sheet member; and transferring the toner remaining on the image carrying means after transferring the toner image on the image carrying means onto the sheet member. Cleaning means for removing the developer from above the developing means, wherein the developing means comprises a developing container containing a developer comprising toner and carrier particles, and applying the developer in the developing container to the image bearing means. And a conveying / stirring means disposed in the developing container, and an upstream path and a downstream path extending in the width direction in parallel in the developing container. The upstream path and the downstream path are communicated with each other at both ends in the width direction, and the conveying / stirring means is provided on the upstream path provided in the upstream path. Side transfer / stirring mechanism and the downstream path A downstream-side conveying / stirring mechanism, the upstream-side conveying / stirring mechanism comprising a rotating shaft extending in the width direction in the upstream circulation path and a spiral blade disposed on a peripheral surface of the rotating shaft. The downstream-side transport / stirring mechanism includes a rotating shaft extending in the width direction in the downstream-side circulation path and a spiral blade disposed on a peripheral surface of the rotating shaft. An image forming machine, comprising: a sleeve member extending in a width direction along a downstream path, wherein the developer present in the downstream path is pumped to a peripheral surface of the sleeve member and applied to the image bearing means. The conveying / stirring mechanism includes a plurality of paddle pieces arranged on the peripheral surface of the rotating shaft at intervals in a circumferential direction, each of the paddle pieces being radially and spirally extending from the peripheral surface of the rotating shaft. A radial leading edge extending axially between the vanes and each of the paddle pieces; An image forming apparatus is located radially inward of an outer peripheral edge of the spiral blade. 2. In the downstream conveying / stirring mechanism, the paddle pieces are disposed substantially uniformly over substantially the entire developing action area of the sleeve member, and each of the paddle pieces is The image forming apparatus according to claim 1, wherein the spiral blade continuously extends between the spiral blades in the axial direction. 3. The upstream conveying / stirring mechanism also includes a large number of paddle pieces arranged on a peripheral surface of the rotating shaft at intervals in a circumferential direction, and each of the paddle pieces is provided around a periphery of the rotating shaft. The image according to claim 1 or 2, wherein the paddle piece extends radially from a surface and axially between the spiral blades, and a radial leading edge of each of the paddle pieces is located radially inward of an outer peripheral edge of the spiral blade. Forming machine. 4. The image forming apparatus according to claim 3, wherein in the upstream conveying / stirring mechanism, the paddle piece does not exist in an axially intermediate region between the spiral blades in at least a part of the rotating shaft. 5. A radial length from a peripheral surface of the rotary shaft to a radial leading edge of the paddle piece is substantially half of a radial length from a peripheral surface of the rotary shaft to a peripheral edge of the spiral blade. The image forming apparatus according to claim 1. 6. The developing means includes a toner replenishing means for replenishing toner in the developing container, the toner replenishing means carrying toner into one end in the width direction of the upstream path, and The transport / stirring mechanism transports the developer in the upstream path in a direction from the one end to the other end, and the downstream transport / stirring mechanism.
The stirring mechanism transports the developer in the downstream path in a direction opposite to the transport direction in the upstream path, and
6. The stirring mechanism according to claim 1, wherein the arrangement density of the paddle pieces at one end and the vicinity thereof is smaller than the arrangement density of the paddle pieces at the other end and the vicinity thereof. An image forming machine according to any one of the above. 7. An image carrying means, an electrostatic latent image forming means for forming an electrostatic latent image on the image carrying means, and an image forming means for developing the electrostatic latent image on the image carrying means into a toner image. Developing means;
Transfer means for transferring the toner image on the image carrying means onto a sheet member; and transferring the toner remaining on the image carrying means after transferring the toner image on the image carrying means onto the sheet member. Cleaning means for removing the developer from above the developing means, wherein the developing means comprises a developing container containing a developer comprising toner and carrier particles, and applying the developer in the developing container to the image bearing means. And a conveying / stirring means disposed in the developing container, and an upstream path and a downstream path extending in the width direction in parallel in the developing container. The upstream path and the downstream path are communicated with each other at both ends in the width direction, and the conveying / stirring means is provided on the upstream path provided in the upstream path. Side transfer / stirring mechanism and the downstream path A downstream-side conveying / stirring mechanism, the upstream-side conveying / stirring mechanism comprising a rotating shaft extending in the width direction in the upstream circulation path and a spiral blade disposed on a peripheral surface of the rotating shaft. The downstream-side transport / stirring mechanism includes a rotating shaft extending in the width direction in the downstream-side circulation path and a spiral blade disposed on a peripheral surface of the rotating shaft. An image forming apparatus, comprising: a sleeve member extending in a width direction along a downstream path, wherein the developer present in the downstream path is pumped up to a peripheral surface of the sleeve member and applied to the image bearing means. The conveying / stirring mechanism includes a large number of paddle pieces arranged on the peripheral surface of the rotating shaft at intervals in a circumferential direction, each of the paddle pieces being radially and spirally extending from the peripheral surface of the rotating shaft. A radial leading edge extending axially between the vanes and each of the paddle pieces; An image forming apparatus is located radially inward of an outer peripheral edge of the spiral blade. 8. The image forming apparatus according to claim 7, wherein in the upstream conveying / stirring mechanism, the paddle piece does not exist in an axially intermediate region between the spiral blades in at least a part of the rotating shaft. 9. A radial length from a peripheral surface of the rotary shaft to a radial leading edge of the paddle piece is substantially half of a radial length from a peripheral surface of the rotary shaft to an outer peripheral edge of the spiral blade. The image forming apparatus according to claim 7 or 8, wherein 10. The developing means includes a toner replenishing means for replenishing toner in the developing container, wherein the toner replenishing means carries toner into one end in the width direction of the upstream path,
The upstream transport / stirring mechanism transports the developer in the upstream path in a direction from the one end to the other end, and the downstream transport / stirring mechanism transports the developer in the downstream path in the upstream path. The upstream side conveying / stirring mechanism conveys the developer in a direction opposite to the conveying direction. The image forming apparatus according to any one of claims 7 to 9, wherein the density is smaller than the disposition density of the image forming apparatus.