JPH03212666A - Developing device - Google Patents

Abstract

PURPOSE:To surely mix and stir the toner freshly supplied into a developing case and the developer existing already in the developing case by providing resilient splashing-up agitating members on the revolving shaft of a developer transfer means. CONSTITUTION:Plural stages of the splashing-up agitating members 55 having adequate resilience and elasticity are provided on the revolving shaft 49 of the developer transfer means 43. The agitating members 55 curve when the members come into contact with a partition wall 58 between an agitating part K and a transfer part I and peripheral walls 56, 57 on the periphery of the transfer means 43. The members extend to project upward from the front surface of the developer G transferred by the transfer means 43 when the contact with the partition wall 58 and the peripheral walls 56, 57 is released. The toner riding atop the developer G is, therefore, included in the internal direction of the developer G by a change in the movement of the agitating members 55 arising from the movement of the transfer means 43, by which the developer G and the toner are surely agitated and mixed within a short period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device installed in an image forming apparatus such as an electrostatographic copying machine or a printer.

[Conventional technology]

For example, some developing devices installed in electrostatographic copying machines use a so-called two-component developer consisting of toner, which is plastic powder, and carrier, which is magnetic metal powder. .

In such a developing device, for example, in the developing case, there is a developer agitation supply device that agitates toner and carrier and supplies the mixture to the developing roller, and a developer agitation supply device that is installed in parallel with the developer agitation supply device with a partition wall interposed therebetween. , a developer transfer tool that transfers the developer introduced from one end of the developer agitation supply tool and the toner supplied from a toner supply port provided in the developing case to the other end of the developer agitation supply tool; A developing roller is provided to supply the agitated developer to the photoreceptor.

By the way, among the developer supplied to the photoreceptor, toner is gradually consumed as it is used for developing the electrostatic latent image formed on the surface of the photoreceptor, and the toner and carrier in the developer are mixed. The ratio (T/D) decreases, but in electrostatographic copying machines, in order to make clear copies, it is necessary that the T/D always be at a predetermined value. It is necessary to detect the toner concentration of the toner and replenish the toner when this toner concentration is less than a predetermined value.

Therefore, in a developing device using a two-component developer, a toner control sensor is conventionally provided in the developing case to control the T/D.

[Problem to be solved by the invention]

However, since the toner is made of plastic powder and is lighter than the developer, it is difficult for the toner supplied from the toner supply port to enter the developer that was originally in the developer case, and the toner does not reach the surface of the developer. Especially in miniaturized developing devices,
Because the distance from the toner supply port to the toner control sensor is short, even if a developer agitation supply device is provided, the newly replenished toner and the developer in the developer case are not sufficiently agitated. There is a problem that the toner concentration cannot be accurately grasped, and the toner on the surface of the developer is scattered outside the developing case from between the developing roller and the photoreceptor, causing damage to other parts of the electrostatographic copying machine. There is a problem in that it stains the parts and the paper used for copying.

On the other hand, it is conceivable to increase the distance from the toner supply port to the toner control sensor to ensure sufficient agitation, but this would increase the size of the developing device and increase the distance. The response deviates by the amount that T/DIil? There is a problem that deviations occur in i.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to ensure that the toner newly supplied into the developing case and the developer already present in the developing case are mixed and stirred. The object of the present invention is to provide a useful developing device that eliminates the above-mentioned problems.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention includes a developer agitation and supply tool that agitates and supplies a developer made of toner and carrier to a developing roller, and a developer agitation and supply tool that agitates and supplies a developer made of toner and carrier to a developing roller. The developer agitation and supply tools are arranged in parallel with each other through a partition wall, and the developer introduced from one end of the developer agitation supply tool and the toner supplied from the toner supply port provided in the developer case are connected to the other end of the developer agitation and supply tool. In the developing device, a rotating shaft of the developer transporting tool is provided with a developer transporting tool for transporting the developer.
It bends when it comes into contact with the partition wall and the peripheral wall around the developer transfer device, and expands when the contact with the partition wall and the peripheral wall is released, and protrudes from the upper surface of the developer transferred by the developer transfer device. It is characterized by the provision of a flexible, flip-up stirring member.

[Effect]

In the developing device according to the present invention having the above-mentioned characteristic configuration, the flip-up stirring member rotates about the rotation axis as the developer transfer device rotates in a predetermined direction. The flip-up stirring member has appropriate flexibility, and is bent when it comes into contact with the partition wall between the developer agitation supply tool and the developer transfer tool or the peripheral wall around the developer transfer tool, and bends when it comes into contact with the partition wall between the developer stirring and supply tool and the developer transfer tool, and the peripheral wall around the developer transfer tool. When the contact with the peripheral wall is released, the developer expands and changes its movement so that it protrudes above the upper surface of the developer being transported by the developer transporting device.This change in the movement of the stirring member causes the upper surface of the developer to change. The toner on the toner is drawn into the developer, and the developer and toner are reliably stirred and mixed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention.

First, FIG. 5 shows an electrophotographic copying machine incorporating a developing device according to the present invention. As will be described later, this electrophotographic copying machine can produce monochrome images or superimpose monochrome images using two different color developers. Not only can a combined image be obtained, but also a full-color image using yellow, cyan, and magenta developers.

Now, in this figure, 1 is the main body of the electrostatic photocopying machine,
A document resting section 2 is formed on the upper surface thereof, and inside thereof, with a photoreceptor 3 at its center, a charging device 4, an exposure section 6 of an exposure optical system 5, a developing section 7 (the structure of which will be described later), A transfer device 8, a paper separation device 9, a cleaning device 10, and the like are provided.

Inside the copying machine body 1, there is a paper feed conveyance device 12 for conveying the paper in the cassette case 11 toward the transfer device 8;
A paper ejection transport device 14 that transports the paper after transfer and separation to the fixing device 13, a pair of paper ejection rollers 16 that ejects the paper after the fixation to the tray 15, and a loading section 17 of the cassette case 11 are provided. A paper refeeding section 18 having a double feeding prevention function is disposed between the paper ejection conveyance device 14 and the paper refeeding section 18, and a paper refeeding path 19 that selectively discharges the fixed paper to the paper refeeding section 18. Further, a conveying device 20 is provided which merges and feeds the sheets after single-sided copying stored in the paper refeeding device 18 to the sheet feeding and conveying device 12, and feeds the sheets fed from the cassette case 11. A copy mode in which an image is copied on one side and the paper after the single-sided copy is discharged as is into the tray 15, and a combination in which the paper after the single-sided copy, which is stocked in the refeeding device 18, is re-fed to the transfer device 8. The configuration is such that the copy format can be selected.

The developing section 7 includes a plurality of (four in the illustrated example) developing devices 2.
1 and a hopper unit 23 for replenishing toner, which are provided so as to be vertically movable.

That is, the developing unit 22 includes four developing devices 21 (detailed configuration thereof will be described later) arranged vertically within a unit frame 24 thereof. On the other hand, in the hopper unit 23, four toner replenishment hoppers 25 each containing yellow, cyan, magenta, and black toners are attached in parallel to the hopper frame 26 in the lateral direction. 25 is a flexible tube 2
7 to the developing device 21, and
Each toner replenishment hopper 25 has a toner feeding helical rotation shaft 29 installed horizontally within the flexible tube 27 and driven by a motor 28, respectively.

Reference numerals 30 and 31 denote two rotation shafts provided in the upper space of the developing section 7 so that the rotation axes are parallel to the rotation axis of the photoreceptor 3. Pulleys 32 and 33 are provided at a predetermined interval,
Wire row 134 to these boo IJ-32, 33
The developing unit 22 and the hopper unit 23 are connected to both ends of the wire lobe 34, respectively.
Both units 22 and 23 can be moved up and down contrary to each other. In addition, one rotating shaft 31 has a speed reduction mechanism (not shown).
A position control means 3 that interlocks and connects a motor 35 for raising and lowering the unit through the unit and selectively positions a developing roller 40 (described later) of the developing device 21 in the developing area of the photoreceptor 3.
6 is linked to the control section 37 of the motor 35, whereby a monochrome image or a full color image can be obtained by selectively positioning the developing roller 40 with respect to the developing area.

Next, referring to FIGS. 1 to 4, the developing device 2
1 will be explained in detail.

First, in FIGS. 1 and 2, reference numeral 38 denotes a developing case that accommodates developer G consisting of toner and carrier. The developing case 38 has an opening in the portion facing the photoreceptor 3 (see FIG. 5). 39 is formed.

Inside the developing case 38, a developing roller 4 is provided.
0, a developer agitation supply tool 41, a developer return member 42, and a developer transfer tool 43 are provided so as to be parallel to the photoreceptor 3.

That is, the developing roller 40 is configured to rotate in the direction of arrow A around a rotation axis 44 parallel to the rotation axis (not shown) of the photoreceptor 3 to convey the developer G toward the surface of the photoreceptor 3. has been done. The developer stirring and supplying tool 41 is formed by forming a spiral blade 46 on a rotating shaft 45 that is parallel to the rotating shaft 44 of the developing roller 40 and rotates in the direction of arrow B.
The developing roller 40 is configured to stir the developer G and supply the developer G toward the developing roller 40. In addition, the developer return member 42
Similar to the developer agitation supply tool 41, this device is formed by forming a spiral blade 48 on a rotating shaft 47 parallel to the rotating shaft 44 of the developing roller 40, and by rotating in the direction of arrow C, the excess on the developing roller 40 is removed. The developer G is fed to the developer agitation supply tool 4.
It is configured to return in one direction.

The developer transfer tool 43 is arranged in parallel with the developer agitation supply tool 41 via a partition wall 58 (described later), and the developer G introduced from one side end of the developer agitation supply tool 41 and the developer case 3
The toner supplied from a toner supply port 62 (described later) provided at 8 is transferred to the other end side of the developer stirring and supplying tool 41 .

That is, this developer transporting tool 43 has a rotating shaft 49 parallel to the rotating shaft 44 of the developing roller 40, and the developer stirring and supplying tool 41.
A spiral blade 50 is formed in the same direction as the spiral blade 46, and a gear 51 is provided at one end of the rotating shaft 49. is mechanically coupled to a gear 54 formed at one end of the rotating shaft 45 of the developer agitation and supply tool 41. Therefore, when the developer agitation and supply tool 41 rotates in the direction of arrow B, the developer transfer tool 43 rotates in the direction indicated by the arrow in the opposite direction, in the transfer section I where the developer transfer device 43 is provided, the developer G and toner are transferred in the direction of the arrow X in FIG. In the stirring section K in which the developer stirring supply tool 41 is provided, a portion of the developer G is stirred and transferred in the direction of arrow Y (opposite direction to arrow X) in FIG.

As shown in FIG. 3, a plurality of flip-up stirring members 55 are provided on the rotating shaft 49 of the developer transfer device 43 by a method such as implantation. This flip-up stirring member 5
5 is bent when it comes into contact with the partition wall 58 and the peripheral wall around the developer transfer tool 43 (such as the bottom wall 56 and the peripheral wall 57 of the developing case 38 (see FIG. 1)), and the partition wall 58 and the peripheral wall 5
6. A material having appropriate flexibility and elasticity, such as piano wire, is used so that it can expand when the contact with 57 is released and protrude from the upper surface of the developer G transferred in the transfer section (3). Also, the tip on the free end side is
As shown in FIG. 4, the rotary shaft 4 is formed in a flat shape, and the rotary axis
It is set at 9.

Reference numeral 58 denotes a partition wall erected at the bottom of the developing case 38 so as to partition the agitation section and the transfer section (2). Developer passages 60 and 61 are formed to allow the developer to move. Therefore, when the developer transfer tool 43 rotates in the direction of the arrow,
The developing JPIC and toner transported in the direction of arrow X are
The developer is sent to the stirring section through the developer passage 60 on the downstream side in the transfer direction of the developer transfer tool 43, and at this time, it is transferred in the direction of arrow Y by the developer agitation supply tool 41 rotating in the direction of arrow B. The developer G is sent to the transfer section I side through the developer passage 61 on the upstream side in the transfer direction.

Reference numeral 62 denotes a toner supply port provided in a part of the earthen wall of the developer case 38, and in the illustrated example, it is located at a position approximately in the middle of the transfer section (2), that is, above the developer transfer device 43 and above the rotation axis 49 of the developer case 38.
It has been established at a location roughly in the center of the city (see Figure 2). The other end of the flexible tube 27 is connected to the toner supply port 62, and a toner feeding helical rotation shaft 63 is provided inside the flexible tube 27. 5) is configured to fall onto the developer G in the transfer section f.

Reference numeral 64 denotes a toner control sensor provided on a part of the bottom wall 56 of the developing case 38, and in the illustrated example, the toner control sensor 64 is located at a downstream position in the transporting direction of the transporting section (2), that is, on the downstream side in the transporting direction (arrow X direction) of the developer transporting tool 43. The developer passage 60 is provided in the vicinity of the developer passage 60 .

In the developing device 21 having the above configuration, the developing case 3 detected by the toner control sensor 64
When the toner concentration in the toner 8 is less than a predetermined value, a predetermined amount of toner T is sent out from the toner replenishment hopper 25 in response to a signal from a control section (not shown), passes through the flexible tube 27, and is further supplied with toner. It is dropped and supplied to the transfer section I through the supply port 62. At this time, the toner T is transferred to the developer G in the transfer section I.
Since the specific gravity is smaller than that of the developer G, the developer will ride on the upper surface of the developer G. However, since the developer transfer tool 43 is rotating in a predetermined direction in the transfer section I, the developer transfer tool 43 will be rotated along with this rotation. A flip-up stirring member 55 provided on the rotating shaft 49 rotates around the rotating shaft 49.

The flip-up stirring member 55 has appropriate flexibility,
Moreover, when it comes into contact with the partition wall 58 between the stirring section and the transfer section I and the peripheral wall 56.57 around the developer transfer tool 43, it is bent, and the contact with the partition wall 58 and the peripheral wall 56.57 is released. At times, the developer G is elongated and protrudes upward from the upper surface of the developer G transferred by the developer transfer tool 43. Therefore, due to the change in the movement of the splashing stirring member 55 accompanying the rotation of the developer transfer tool 43, the developer G is The toner T riding on the toner T is drawn into the inside of the developer G, and the developer G and the toner T are reliably stirred and mixed within a short time. In particular, as shown in the illustrated example, since the distal end of the free end of the flip-up stirring member 55 is formed flat, the toner T is drawn in and the toner T and developer G are mixed and stirred reliably.

Then, when the developer G in the transfer section (2) is mixed and stirred with the newly supplied toner T and passes through the toner control sensor 64 provided on the downstream side in the conveyance direction of the transfer section (2), the toner concentration changes. However, as described above, the developer G and toner T are detected sufficiently within a short time, that is, during the time between the developer G and toner T from the toner supply port 62 to the toner control sensor 64. Since the components are mixed and stirred, T/D can be detected accurately.

Further, since the toner T is no longer placed on the upper surface of the developer G, the toner T is prevented from scattering outside the developing case 38. Further, since the distance from the toner supply port 62 to the toner control sensor 64 can be reduced, the developing case 38 and, by extension, the developing device 21 can be downsized, and responsiveness is improved, and the T/
D control can be performed stably.

In the above-described embodiment, the toner control sensor 64 is provided at the bottom of the developing case 38, and furthermore, on the way from the transfer section I to the agitation section, to control the toner concentration of the developer G before being supplied to the developing roller 4o. However, the present invention is not limited to this, and the toner concentration of the developer G cut into spikes by the developing roller 40 may be detected.

That is, FIGS. 6 and 7 show an example of a developing device configured as described above, and in these figures, the same reference numerals as those in FIGS. 1 to 5 indicate the same or equivalent parts. .

In the developing device 65 of this embodiment, the developing roller 40
The developing roller 4 is connected to a cutting plate 66 that cuts off excess developer G on the developing roller 40 as the developing roller 4 rotates in a predetermined direction.
The developer agitation supply tool 41 is provided above the developer agitation supply tool 41 while biasing the developer G after cutting the ears toward one end side of the developer agitation supply tool 41.
A partition plate 67 that allows the toner to flow back upward is provided in the developing case 38, and a toner control sensor 64 is provided in the developing case 38 near the cutting plate 66, that is, in the upper wall 68 of the developing case 38.

It goes without saying that the effects of the developing device t65 constructed in this way are similar to those of the above-described embodiment.

The spring-up stirring member 55 only needs to have at least flexibility, and therefore may be made of a suitable resin and its shape can be set arbitrarily.

〔Effect of the invention〕

As explained above, the developing device according to the present invention bends when the rotating shaft of the developer transporting tool comes into contact with a surrounding partition wall, etc., and extends when the contact with the partition wall etc. is released, Since it is equipped with a flexible stirring member that protrudes from the upper surface of the developer transferred by the developer transfer device, the newly replenished toner in the developer case and the developer originally present in the developer case are separated. Stirring and mixing with the toner is reliably performed in a short period of time, and therefore the toner concentration of the developer can be detected accurately.As a result, T/D control by the toner control sensor is stabilized, and stable development is always performed. be able to.

And, since the stirring and mixing can be performed in a short time,
Since the toner is sufficiently stirred with the developer, the toner is not scattered from the developing case, and the members around the developing device and the paper used for image formation are not soiled.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a sectional view showing the configuration of a developing device according to the invention, FIG. 2 is a developed view showing the main parts thereof, and FIG. FIG. 4 is an enlarged sectional view showing an example of a developer transfer device, FIG. 4 is an enlarged perspective view showing an example of a flip-up stirring member, and FIG. 6 and 7 show other embodiments of the present invention, and FIG.
The figure is a sectional view showing the structure of the developing device according to the present invention, and FIG. 7 is a perspective view showing the main parts thereof. 21.65...Developing device, 38...Developing case, 4
0...Developing roller, 41...Developer stirring supply tool, 4
3...Developer transfer device, 55...Splash stirring member,
56.57... Peripheral wall, 58... Partition wall, 62... Toner supply port, G... Developer, T... Toner Applicant: Sanda Kogyo Co., Ltd. Agent

Claims (1)

[Claims] Inside the developing case, there is a developer agitation and supply tool that agitates the developer consisting of toner and carrier and supplies it to the developing roller, and a developer agitation and supply tool that is installed in parallel with the developer agitation and supply tool through a partition wall. A developing device provided with a developer transfer device that transfers the developer introduced from one side end of the tool and the toner supplied from a toner supply port provided in the developer case to the other end side of the developer agitation supply device. In this case, when the rotating shaft of the developer transfer device comes into contact with the partition wall and the peripheral wall around the developer transfer device, it is bent, and when the contact with the partition wall and the peripheral wall is released, it is extended, and the developer transfer device is bent. A developing device characterized by being provided with a flexible flip-up stirring member that protrudes from the upper surface of the developer transported by the tool.