JPH04115268A - Developing device - Google Patents

Abstract

PURPOSE:To prevent toner clogging by means of a toner mass and the leakage of toner by providing the communicating parts of a developer on the top surface side of the developer container of partition plates, and flowing the developer into the other housing rooms through the communicating parts when the fluidity of the developer is reduced and pressure is added on the upper parts of the housing rooms. CONSTITUTION:A developing sleeve 11 is disposed on the front opening part of the developer container 10. A doctor blade 12 regulating the coating of the toner is attached to a supporting plate 13 on the upper part of the developing sleeve 11. On the other hand, the developer container 10 is partitioned by the partition plates 30 and 31, inside, to obtain respective housing rooms of a developing room 20, a stirring room 21, and a hopper room 22. Respective stirring/carrying members 40, 41, and 42 are sequentially rotatively disposed in respective housing rooms, and the toner is carried to the side of the developing sleeve 11 while being stirred. The toner is carried from communicating/opening parts formed on the lower parts of the partition plates 30 and 31. On the other hand, openings are provided on the upper parts of the partition plates, as well, and the communicating parts among respective housing rooms are formed. Thus, even if the fluidity of the toner is reduced, and the toner is compressed on the upper parts of the housing rooms, the toner flows into the other housing rooms through the communicating parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device for visualizing electrostatic latent images such as electrophotography.

C. Prior Art] Conventionally, developing devices using a -component developer (hereinafter referred to as toner) have been of the enclosing type as shown in FIG. 7, or as shown in FIG. 8, depending on the position of a part of the hopper. It can be divided into independent types such as As shown in FIG. 7, the enclosing type developing device consists of a hopper portion 22 and a developing section 20, each of which is provided with an agitating member 42, 40. The hopper of the enclosing type developing device is usually of a fixed-quantity replenishment type, and when the remaining toner sensor 14 in the hopper chamber indicates that the toner capacity is low, a display prompts the user to replenish toner. On the other hand, those with independent hoppers are
As shown in FIG. 8, it is called a small amount replenishment type, and a toner level sensor 15 in the developing chamber rotates a replenishing member 16 to keep the amount of toner in the developing chamber constant, and toner is replenished little by little from a hopper container. This is what we do. This type of developing device further includes a remaining toner sensor I4 that detects the amount of toner in the hopper container and indicates that there is no toner in the hopper.

In the case of the above-mentioned C-shaped fixed-quantity replenishment type, the toner in the developer container and the replenishment toner are supplied to the developing sleeper, which is a developer carrier, before they are sufficiently mixed during replenishment, as shown by the solid line a in FIG. This resulted in extreme density unevenness or thinness that could be seen.

In Fig. 9, the "heter image density" is the image formed by the contrast of the dusk area, measured using a reflection densitometer.In order to solve this problem, It is known to attach a partition plate 32 to restrict the movement of toner.However, since there is not enough space for the toner to be fed by the conveyance device inside the hopper to be sufficiently agitated, the solid line shown in FIG. As shown in the figure, subtle density unevenness or lightness has not been completely resolved.

On the other hand, in a small quantity replenishment system with an independent hopper, by replenishing small amounts at a location away from the developing section, it is constantly stirred little by little to suppress the shock during replenishment and prevent thick and thin concentrations. I'm there. However, since a small amount TiJ supply type developing device has an independent hot-sover section, a large space is required above the developer container, making the entire device large. Furthermore, a sensor and a control system are required to keep the amount of toner in the developer container constant, and electrical control becomes complicated. In addition, if the type is to supply the liquid at a location away from the developing section, one stirring member or one conveying member is required.

Therefore, a developing device as shown in FIG. 11 was proposed as a structure that takes advantage of the advantages of the above-mentioned enclosed type and independent type. This developing device includes a developing chamber 20 and a hopper chamber 22.
A developer agitation and conveyance member 41 (hereinafter referred to as agitation and conveyance member) is provided between the developer agitation and conveyance member 41, and two partition plates (10) are provided before and after the agitation and conveyance member 41 to regulate the cross-sectional area of toner movement. ，
31 are arranged. The storage chamber surrounded by the partition plates 30 and 31 is a stirring chamber 2I independent of the L developing chamber 20 and the hopper chamber 22. Although it has the external shape of a fixed-rate replenishment type that does not have an independent hopper 23 as shown in Fig. 8 or a sensor I5 for replenishing small amounts and a control system, etc., it has the advantage of not causing concentration unevenness or thinning during replenishment. It is something that

[Problem to be solved by the invention] However, when the amount of toner consumed decreases and a large amount of toner is stored in each storage chamber, and the fluidity of the toner decreases due to a low humidity environment, However, there have been problems in that the toner is compressed in the upper part of the storage chamber surrounded by the partition plate and the upper wall of the developer container, resulting in toner lumps and toner clogging. Furthermore, there was a problem in that toner leaked from the developing chamber due to poor fluidity within the storage chamber.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a developing device that does not cause toner lumps, toner clogging, or toner leakage.

[Means for Solving the Problems] According to the present invention, the above objects include: a developer container for storing a developer; and a plurality of storage chambers formed by partitioning the inside of the developer container into front and back, a partition plate having a communication opening on the bottom side of the drug container;
The developer carrier is rotatably arranged in each storage chamber partitioned by the partition plate, and stirs the developer in the storage chamber, and connects the developer carrier from the rear storage chamber through the communication opening to the front storage chamber. In the developing device including a developer stirring and conveying member that conveys the developer to a chamber, the partition plate is disposed so as to have a developer communication portion on the upper surface side of the developer container. This is achieved by

[Function] According to the present invention, when the fluidity of the developer decreases and pressure is applied at the upper part of the storage chamber, the developer flows into another storage chamber through the communication portion formed in the partition plate. I wanted to,
To suppress the occurrence of toner lumps and toner clogging, and also to prevent toner leakage.

[Example] The first to fourth embodiments of the present invention are illustrated in the first to fourth embodiments of the attached drawings.
This will be explained based on FIGS. 6 to 6.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

In FIG. 1, IO is a developer container and is made of ABS resin. A developing sleeve 11, which is a developer carrier made of stainless steel and having a magnetic field generating means (not shown) therein, is disposed at the front opening of the developer container IO. Above the developing sleeve 11, there is a doctor plate 12 made of magnetic metal or a support plate 13 made of stainless steel that regulates the coach ink of the developer (hereinafter referred to as toner).
is attached to. Furthermore, inside the developer container 10, A
It is partitioned by a partition plate 30 and a partition plate 31 made of BS resin, and is divided into a developing chamber 20, a stirring chamber 2], and a hopper chamber 22. Each of the storage chambers includes developer agitation and conveyance members (hereinafter referred to as agitation and conveyance members) 40, 41.
42 are rotatably disposed in sequence, and convey the toner to the developing sleeve 11 side while stirring the toner.

The toner is conveyed through communication openings formed at the lower portions of the partition plates 30 and 31, as shown in the second ['A].

In addition, in this embodiment, the upper part of the partition plate also has an opening, so as to form a communication section between the respective storage chambers, as shown in FIG.

According to this embodiment, even if the fluidity of the toner decreases and the toner is compressed in the upper part of the storage chamber, the toner flows into the other storage chamber through the communication portion, resulting in toner lumps, toner clogging, and toner leakage. will not occur.

In order to confirm such an effect, the following experiment was conducted. The conditions are as follows.

(Conditions) Developing device size: Height 70mm, Radius 130mm, Longitudinal length 300mm Developing sleeve diameter 20+V, Circumferential speed 225mm/s Counterclockwise development chamber agitation conveyance member 40: Diameter 2mm, Circumferential speed 5 rpm
, clockwise, rotation radius 12mm stirring conveyance member 4 of stirring chamber
■: Diameter 21■, circumferential speed 20 rpm, clockwise, rotation radius 20 points Hopper chamber stirring and conveying member 42: diameter 2t+w
, circumferential speed 11 rpm, radius of one rotation clockwise 31 degrees. Note that the stirring and conveying members 40, 41, and 42 are made of stainless steel,
As shown in Figure 3, it has a crank shape.

Toner: Negatively charged styrene acrylic toner 00g When I printed about 10,000 sheets under the above conditions, I was able to obtain a good solid density of 1.4 on average. In addition, there is approximately 1 toner in the hopper container.
Either 50g of toner was replenished to create an excess toner condition in the developing device, and the toner overflowed into the developing chamber and stirring chamber to produce an image, or the toner overflowed through the communication part without becoming clogged. It had no effect on image density, etc.

Second Embodiment Next, a second embodiment of the present invention will be described based on FIGS. 4 and 5. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

This embodiment differs from the first embodiment in that the communicating portion of the partition plate 3 is lower than the communicating portion of the partition plate 30. developing room,
When the amount of developer in both the stirring chamber and the hopper chamber increases and the 5M flow area rises, toner that is not being stirred moves in the upper part of the developing device, making it impossible to obtain the effect of making the storage chamber independent. In other words, unstirred toner entered the developing chamber, causing uneven density in the image. Therefore, as shown in FIG.
Partition plate 3
1 into the shape shown in Figure 5. Partition plate 3
The positional relationship is such that the communication part of the partition plate 31 is lower than the communication part of the partition plate 31. As a result of a durability test conducted under the same conditions as the experiment in the first embodiment, the flow of toner from the stirring chamber into the developing chamber was completely eliminated.

<Third Embodiment> Next, a third embodiment of the present invention will be described using FIG. 6. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

This embodiment differs from the second embodiment in that a valve is provided in the communication portion of the partition plate 31.

In the first embodiment, when a large amount of toner is replenished into the hopper part 22, there is a problem in that the toner flows directly from the hopper chamber into the stirring chamber 2 from the communication section.

In particular, when replenishing 400 g or more of toner when the amount of remaining toner in the stirring chamber is low, it has been confirmed that the toner may flow directly into the stirring chamber or be transported to the developing chamber without being stirred well, resulting in uneven image density. Figure 6 shows a regulating member equipped with an overflow valve 33 to prevent the toner from flowing in during replenishment.Since the toner level in the developing device is low at the time of replenishment, there is no need for overflow. , is configured to block the communication part. With the developing device equipped with this valve 33, the amount of remaining toner is 150.
If it's more than 4g, even if you replenish 450g of toner. There were no adverse effects such as uneven density. However, when the amount of remaining toner falls below 150 g, there is almost no toner remaining in the stirring chamber, and the effect of the stirring chamber is lost, so that C degree thinning during replenishment could not be prevented.

<Fourth Example> Next, a fourth embodiment of the present invention will be described.

Note that the same reference numerals are given to the same parts as in the third embodiment, and the explanation thereof will be omitted.

In the third embodiment, if the overflow valve 33 is expanded by the pressure of the toner inside the agitation chamber, or if even a small amount of toner remains in the hopper chamber, the operation of the valve becomes difficult. Therefore, when the valve 33 was repeatedly opened and closed once every two seconds, a good overflow was obtained although some toner flowed in from the hopper chamber.

In addition, in this embodiment, the timing for moving the movable valve may vary depending on the environment in which the developing device is placed.
In a low-humidity environment, toner tends to overflow due to its low fluidity, and toner clogging could be resolved by opening the overflow valve more times.

Also, if the toner has high fluidity in a high humidity environment,
Good agitation was achieved by reducing the number of times the valve was opened to prevent toner from flowing into the hopper chamber.

In the following examples, either a styrene acrylic negatively charged toner was used as the toner, or 0.5% of silica was externally added to this toner to improve its fluidity. The height of the L portion level of the toner was lowered, making it difficult to overflow, and even when the level was higher, smooth overflow occurred.

[Effects of the Invention] As explained above, according to the present invention, since the partition plate or the developer container has the communication portion on the upper surface side, even if the fluidity and conveyance state of the developer changes, the toner remains unchanged. No lumps, toner clogging, or toner leakage.

Therefore, a good developing state can be maintained for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a schematic configuration of the apparatus according to the first embodiment of the present invention, FIG. 2 is a plan view showing a schematic configuration of a partition plate with the first partition, and FIG. 3 is a stirring apparatus of the first embodiment of the present invention. 4 is a plan view showing a schematic structure of the conveying member, FIG. 4 is a cross-sectional view showing a schematic structure of a device according to a second embodiment of the invention, FIG. FIG. 6 is a cross-sectional view showing a schematic configuration of a device according to a third embodiment of the present invention, FIG. 7 is a cross-sectional view showing a schematic configuration of a conventional built-in type device, and FIG. 8 is a schematic diagram of a conventional stand-alone device. FIG. 9 is a cross-sectional view showing the configuration; FIG. 9 is a diagram showing the transition of image density when the devices in FIG. 7 and the device in FIG.
FIG. 0 is a sectional view showing a schematic configuration of a conventional device using one partition plate, and FIG. 1.1 is a sectional view showing a schematic configuration of a conventional device using two partition plates. 10......Developer container 30.
31・・・・・・・・・Partition plate

Claims (2)

[Claims] (1) A developer container that stores developer; a partition plate that forms a plurality of storage chambers by partitioning the inside of the developer container back and forth, and that has a communicating opening on the bottom side of the developer container; It is rotatably arranged in each storage chamber partitioned by a plate, stirs the developer in the storage chamber, and flows from the rear storage chamber to the front storage chamber in which the developer carrier is arranged through the communication opening. and a developer stirring and conveying member for conveying the developer, wherein the partition plate is disposed so as to have a developer communication portion on the upper surface side of the developer container. A developing device. (2) The developer according to claim (1), wherein the communication portion is arranged such that the developer flows in one direction from the front storage chamber to the rear storage chamber. Device.