JPS61196273A - Electrophotographic developing device - Google Patents

Abstract

PURPOSE:To reduce the weight and size of an electrophotographic developing device and to facilitate its extraction and replacement by taking a toner supply part out while the supply part contains toner without a toner carrier. CONSTITUTION:When a developing unit B which includes a toner tank 6 needs to be replaced, a solenoid 11 is operated firstly to rotate the bottom wall 63 of the toner tank to the position where the toner tank 6 is separable, and then the solenoid 11 and a spring member 12 are disengaged from each other to place the developing unit B in a free state. Then, the developing unit B is drawn out as shown by an arrow Y and then a toner layer thickness control member 7 is rotated to a developing roll 2 side with the pressing force of an elastic member 9 and locked by a projection part 62a to close an opening part 6a above the developing roll 2, so that toner is stored in toner storage space above the toner tank 6. Further, the developing unit B is drawn out upward.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic developing device used in copying machines, facsimile machines, printers, etc. The present invention relates to an electrophotographic developing device including a toner supply section that supplies toner.

``Prior Art'' Conventionally, for example, a developing roll that carries toner and transports it to a developing position (a position facing the photosensitive drum) is placed on the opening side facing the photosensitive drum in a toner tank containing toner. , a developing device in which a layer thickness regulating member for regulating the thickness of the toner layer carried on the developing roll is arranged upstream of the facing position is already known, and this type of device is easy to assemble and maintain. In order to achieve this, various excitation members are integrated into a unit, and each unit can be taken out or replaced.

"Problems to be Solved by the Invention" However, if all the members of the developing device are integrated in this way, if the toner layer thickness regulating member or other parts become worn out, they must be replaced for each unitized developing device. First, even if the particularly expensive developing roll is still usable, it must be discarded, which tends to increase replacement costs.

Furthermore, since all of these various members are stored in the toner tank, it is not possible to check the degree of deterioration of the members, and development may be performed in a deteriorated state, which tends to deteriorate the quality of development.

Furthermore, since the developing roll includes a fixed magnet assembly, it has various drawbacks, such as the fact that the weight burden tends to be large when it is removed.

In addition, in recent years, various so-called color image forming apparatuses that form images using toners of different colors have been proposed, but when this developing unit is applied to such apparatuses,
Color developing units that integrate the developing roll and other developing members must be prepared for the corresponding number of colors, and as mentioned above, developing rolls are extremely expensive, and developing units that include developing rolls are inevitable. Due to the large size of the developing unit, preparing a plurality of such developing units is likely to cause problems both in terms of cost and storage space for both the manufacturer and the user.

In view of the drawbacks of the prior art, the present invention has a structure in which the toner carrier (developing roll) and toner supply section (toner tank) can be separated while maintaining the unitization effect, thereby facilitating maintenance work and An object of the present invention is to provide an electrophotographic developing device suitable for the color image forming apparatus.

"Means for Solving the Problems" In order to achieve the above technical problems, the present invention provides an electrophotographic developing device that includes at least a toner carrier and a toner supply section that supplies toner to the carrier. A technique in which a closing means is provided to close an opening on the toner supply section side facing the toner carrier, and the toner supply section and the toner carrier/special holiday can be separated while the toner is stored in the toner supply section. Suggest a method.

In this case, by configuring the toner supply section so that it can be separated in a direction away from the toner carrier, there is no risk of damaging the surface of the toner carrier during the separation.

Preferably, the closing means includes a layer thickness regulating member that regulates the layer thickness of the toner carried on the toner carrier, and further applies an elastic force to the toner layer thickness regulating member. It is preferable that the opening of the toner supply section be configured to be automatically closed.

"Function" According to this technical means, the toner supply section can be taken out without containing the toner carrier and with the toner stored therein, so that it is lightweight and compact, and furthermore, it is easy to take out and replace it. become.

In addition, since the toner carrier can be taken out independently, its degree of deterioration can be easily checked, and the toner layer thickness regulating member can also be used as a closing means to prevent toner supply. When the part is taken out, the side of the toner layer thickness regulating member facing the toner carrier is exposed to the outside, so it is easy to check the degree of deterioration, facilitating maintenance and inspection, and preventing deterioration in development quality. It is possible.

Furthermore, the toner supply section is configured such that the toner can be separated and taken out from the toner carrier while the toner is stored in the supply section, and since the toner supply section does not include a toner carrier, the toner supply section can be produced at an extremely low cost, and as a result,
The toner supply section itself can be made into a cassette and formed as a toner replenishment cartridge, and as a result, the hassle of toner replenishment can be eliminated.

Furthermore, it is also possible to unitize all the members constituting the developing device except the toner supply section and the toner carrier, since the unit does not include an expensive toner carrier (developing roll). , can be manufactured inexpensively and compactly.

As a result, even if this developing unit is applied to the color image forming apparatus and a corresponding number of different color units containing toners of different colors are prepared, the different color units do not require extremely expensive developing rolls. Since it is not included, there is no problem in terms of cost or storage space.

In this case, the different colored toner remaining on the toner carrier side can be removed by rotating the toner carrier with the toner supply section separated and performing a cleaning process (peta black copy) on the carrier. It is possible to clean toners that are mixed with other colors, and toners of different colors do not mix even in the early stages of reproduction.

On the other hand, since the toner carrier is also configured separately from the developing unit, by integrating the toner carrier with the electrostatic latent image carrier, the facing distance between the two can be kept constant. A good and uniform developing effect can be maintained.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. It's nothing more than that.

1 to 3 show a developing device according to an embodiment of the present invention.

In FIG. 3, 1 is a photosensitive drum with a photoconductive layer formed on its surface; 2 is a developing roll containing a fixed magnet assembly 3; A member 1.2 is rotatably supported and fixed, and both members 1,
The facing interval between the two is maintained at a constant interval.

A gear train 4 driven by a drive source (not shown) is fitted to the rotating shafts 1a and 2a, and the photosensitive drum 1
and the developing roll 2 are configured to rotate at the same circumferential speed in the directions indicated by the arrows.

And these photoreceptor drums 1. The developing roll 2, fixed arm 5, and gear train 4 are integrally assembled to form a drum unit A.

Further, as shown in FIGS. 1 and 2, the developing roll 2
The fixed magnet assembly 3 enclosed in the fixed magnet assembly 3 has a plurality of fixed magnets 3a... arranged at predetermined positions on its outer peripheral surface,
Fixed magnets 3a and 3b of the same polarity are arranged adjacent to each other at the toner layer thickness formation position upstream of the development position, so that a repulsive magnetic field is formed by the fixed magnets 3a and 3b at the toner layer thickness formation position on the developing roll 2. Configure.

B is a toner tank surrounding the developing roll 2;

a vertical jJi 81 located downstream of the toner layer thickness forming position with its lower end close to the developing roll 2; and a vertical jJi 81 located upstream of the toner layer thickness forming position with its lower inner wall surface facing the developing roll 2. It consists of an inclined wall 62 arranged close to each other and a bottom wall 63 rotatably supported at the lower end of the inclined wall 62, and the space between the vertical wall 81 and the inclined wall 82 is surrounded by a pair of side walls (not shown). Ori.

The toner is configured so that it can be stored above the developing roll 2.

Further, above the toner layer thickness forming position between the vertical wall 61 and the inclined wall 82, a partition wall θ4 is arranged parallel to the vertical wall 81.

A toner layer thickness regulating member 7, a magnet blade 8, and an elastic member 8, which will be described later, are integrally assembled in the toner tank 8 to constitute a developing unit B that can be separated from the drum unit A.

Next, the configurations of the various members will be explained.

The toner layer thickness regulating member 7 is formed of a non-magnetic conductive material,
It is rotatably supported at the lower end of the vertical wall 61, extends in a substantially straight line upstream of the developing roll 2 from its base-end rotation fulcrum 7a, and is disposed upstream of the layer thickness regulation position. After contacting the developing roll 2 at a position facing the fixed magnet 3a, the roller is further extended upstream, and its free end is connected to the inclined wall 8.
2, and a predetermined opening 8a is provided between the protrusion 82a and the free end.

In addition, this layer thickness regulating member 7 generally has a thickness of 105Ω/cm''
It is preferably made of phosphor bronze, aluminum plate, etc. having the following surface resistance, and as described later, the free end of the layer thickness regulating member 7 is latched to the protrusion E12a to close the toner tank opening 8a. When this happens, the toner tank 8 has a wall thickness and rigidity that will not bend due to the weight of the toner stored in the toner tank 8.

Further, the magnetic blade 8 has its tip side connected to the fixed magnets 3a, 3.
b, and is arranged to hang down from the lower end of the partition wall 64 in proximity to the back side of the layer thickness regulating member 7, and its tip is located in the repulsion magnetic field forming area by the fixed magnets 3a and 3b. Deploy.

The elastic member 9 is formed into a thin plate shape, hangs down from the upstream wall of the magnet blade 8, and is connected to the layer thickness regulating member on its free end side. The back side is arranged so that it can be pressed.

Further, a solenoid 11 and a spring member 12 are disposed facing each other on the inner and outer walls of the bottom wall 63 supported at the lower end of the inclined wall 62, and the operation of the solenoid 11 causes the bottom wall 83 to move into the toner tank. B is rotated to the separable position (the position shown in FIG. 2), and when the solenoid 11 returns, the spring member 12 returns it to the initial position (the position shown in FIG. 1).

Next, the operation of this embodiment will be explained.

FIG. 1 shows a state in which a developing unit B and a drum unit A are arranged at predetermined positions, and in this state, the following image formation is performed.

That is, the photosensitive drum 1 and the developing roll 2 are rotated in the direction of the arrow through the gear train 4 by the driving of the driving source. On the other hand, since the toner storage space of the toner tank 8 above the developing roll 2 is opened between the free end of the layer thickness regulating member 7 and the inclined wall 62,
Toner is supplied onto the developing roll 2 from the opening 8a,
By rotating on the developing roller 2, the developing roller 2 is not frictionally charged and is transported to a contact position on the upstream side of the layer thickness regulating member 7.

At the contact position, after the layer thickness of the toner is controlled to be thin and uniform by the layer thickness regulating member 7 maintained at a predetermined contact pressure by the elastic force of the elastic member 9, the magnetic blade 8 on the downstream side It reaches within the repelling magnetic field formation region located.

In the repulsive magnetic field forming region, the re-fixed magnets 3a and 3b
After the toner layer is rearranged and thickened by the repulsive force of the magnet blade 8 and the toner layer is thickened, the toner layer is conveyed to a developing position, and the electrostatic latent image is held at the developing position. The toner is selectively transferred onto the drum 1, and then the visualized toner is conveyed to the photosensitive drum 1 to form a predetermined image.

Now, after the completion of the development or during the development, the development unit B including the toner tank 6 may be used for toner replenishment or other reasons.
If it becomes necessary to replace the
First, the solenoid 11 is activated to rotate the toner tank bottom wall B3 to the position where the toner tank 8 can be separated (the position shown in FIG. 2), and then the solenoid 11 and the spring member 12 are disengaged, The developing unit B is set in a free state, and then the developing unit B is moved in the direction of the arrow Y, that is, the developing roll 2
By pulling it out in the direction of further separation, the toner layer thickness regulating member 7 is rotated toward the developing roll 2 by the pressing force of the elastic member 9, and is exposed to the protrusion 62a, and the opening 6a above the developing roll 2 is pulled out. is closed, and the toner is stored in the toner storage space above the toner tank 8. Further, the developing unit B is configured to be able to be pulled out upwardly or in the direction of one axis of the photoreceptor drum, and the developing unit B
By pulling out the developing unit B, the developing unit B can be taken out without damaging the photosensitive drum 1.

When the developing unit B is returned to the predetermined position, the toner layer thickness regulating member 7 automatically comes into contact with the surface of the developing roll 2 by performing the opposite operation to the above, and then the protruding portion 82a
The opening 6a above the developing roll 2 is opened, and toner can be supplied from the toner storage space to the developing roll 2 side.

In this case, since the toner layer thickness regulating member 7 is biased with a predetermined elastic force by the elastic member 8 on its back side, even if the developing unit B is repeatedly removed and installed, the developing roll 2 remains unchanged. The contact pressure of the layer does not fluctuate, making it possible to regulate the layer thickness at a constant level.

In this way, in addition to the effects of the present invention, in this embodiment, the toner tank 6 is closed and opened by the toner layer thickness regulating member 7, so the number of parts can be reduced and the structure can be simplified. is achieved, and furthermore, since an elastic force is applied to the back side of the layer thickness regulating member 7, the separation and installation of the developing unit B and the drum unit A, that is, the toner tank 6 and the developing roll 2, will cause the opening to close. 6a can be automatically closed and opened, further facilitating maintenance work, and even with this configuration, the thickness of the toner layer, which is regulated, will not fluctuate.

"Effects of the Invention" As described above, according to the present invention, the toner supply section can be separated and taken out with toner stored therein, separately from the toner carrier, and as a result, various members constituting the developing device can be removed. It is possible to confirm the degree of deterioration of the toner, eliminate the hassle of toner replenishment, and facilitate maintenance and inspection work.

Further, according to the present invention, since the developing device excluding the toner carrier is unitized, the developing unit can be made lighter, smaller, and less expensive.As a result, the developing unit is particularly suitable for color image forming apparatuses. Equipment can be provided.

It has various effects such as

[Brief explanation of drawings]

Figures 1 to 3 all show embodiments of the present invention; Figure 1 shows a state in which the developing unit and drum unit are placed at predetermined positions, and Figure 2 shows a state in which the developing unit and drum unit are arranged at predetermined positions. FIG. 3 is a schematic cross-sectional view showing a state in the middle of separation, and FIG. 3 is a schematic view showing the configuration of the drum unit. Figure 1 Figure 3

Claims (1)

[Claims] 1) In an electrophotographic developing device that includes at least a toner carrier and a toner supply unit that supplies toner to the carrier, an opening on the side of the toner supply unit that faces the toner carrier is closed. An electrophotographic developing device characterized in that a closing means is provided so that the toner supply section and the toner carrier can be separated while the toner is stored in the toner supply section.2) The toner supply section is a toner carrier. 3) The electrophotographic developing device according to claim 1 is configured to be separable in a direction in which the toner is separated from the toner carrier. 4) An electrophotographic developing device according to claim 1 or 2, wherein an elastic force is applied to the toner layer thickness regulating member, and the elastic force causes the toner supply section side to An electrophotographic developing device according to claim 3, characterized in that the opening is configured to be automatically closed.