JPS58181072A - Dry type developing device - Google Patents

Abstract

PURPOSE:To prevent agglomeration of toner located near a secondary developer layer thickness regulator, by controlling the relative positions of a primary developer layer thickness regulator in a developer tank and the secondary regulator for regulating the layer thickness of the developer fed out of the tank and the magnetic poles opposite to the two regulators. CONSTITUTION:Magnets 3 are arranaged in a rotary sleeve 2. A primary regulator 6 for regulating the layer thickness of developer on the sleeve 2 is installed in a developer tank 4, and a doctor blade 7 for regulating the layer thickness of the developer fed out of the tank 4 with a sleeve 2 is installed at the outlet of the tank 4. At least one of two lines joining the centers of magnetic poles 3a, 3b opposite to thes regulators 6, 7 with the center of magnetic roll are provided more forward in the direction of feeding the developer than the two lines joining the regulators 6, 7 with the center of the magnetic roll, by theta1 or theta2. Preferable theta1 and theta2 are 0-15 deg., more preferably, 4-10 deg., and more favorable results are obtained by setting theta3, as shown in the figure, to 50-70 deg..

Description

[Detailed Description of the Invention] A tank containing a developer, a primary regulation part paulownia for primarily regulating the layer thickness of the developer on a developer carrier present in the tank, and a tank that is removed from the tank. a secondary regulating member for secondarily regulating the layer thickness of the developer;
first and second magnetic poles located substantially opposite to each of the primary and secondary regulating members, and transporting from the tank. -J The present invention relates to a dry developing device that visualizes a latent image formed on a latent image carrier using a stone developer.

Developing devices of the above type are well known in the art and are used in various recording devices such as electronic copying machines, electrostatic recorders, laser printers, and magnetic printers. In this type of developing device V, the layer thickness of the developing material on the developer carrier is primarily roughly regulated by a primary regulating member in a tank containing the developer. ) The layer thickness of the regulated developer is 2.
Since the structure is such that the secondary regulating member further regulates the developer and transports it out of the tank, it is possible to prevent an excessive amount of developer from being added to the secondary regulating member. It is possible to suppress deterioration of the agent. Current 1
'In the gap between the 4-carved support body and the secondary rising part,
This is because if a large amount of developer is forced to be fed in just one step, an excessive load will be applied to the developer attempting to pass through this gap, and the deterioration of the developer will be accelerated. In this way, this type of developing device is able to reduce developer deterioration compared to the conventionally known developing device V which does not have a regulating member in the tank. Since the developer continuously enters the VC secondary regulation member and breaks off, the developer partially accumulates in the vicinity of this secondary regulation member, and as seen in C, a reservoir of detergent '=! It has recently been discovered that there is a risk of agglomeration and solidification over time. The developer is like this V
Once solidified, the layer of developer after passing through the secondary regulating member will have sliver-like unevenness, and the stone that makes the latent image visible will become loose. Obtaining a visible image becomes difficult.

The present invention aims to provide a dry developing device capable of alleviating the above-mentioned conventional drawbacks. Advantageous embodiments of the present invention will be described below, and the above-mentioned conventional drawbacks will also be illustrated in the drawings. This will be explained in more detail.

FIG. 1 is a partial diagram showing an example of a laser printer equipped with a developing device 1 according to the present invention. Illustrated phenomenon device]
has a developer carrier configured as a sleeve 2, and the sleeve 'lvC has a plurality of magnets 3 disposed inside. Each magnet 3 extends parallel to the sleeve 2 and extends over the entire length of the sleeve 2. The magnet 3 is fixed and fixed, but the sleeve 2 is rotatably driven in the counterclockwise direction in the figure. The polarities S and N of the magnetic poles on the snoop 2 side of each magnet are as shown in the figure.
The polarity is alternately reversed. Reference numeral 4 denotes a tank containing the developer 5, and the sleeve 2 is located in the lower opening of the tank 4. As the developer 5, a magnetic developer in which at least a portion of the developer is made of a magnetic material is used, for example, a one-component developer containing toner is used. A primary regulating member formed as a regulating rod 6 is fixedly installed in the tank 4, and it is desirable that this primary regulating member is made of a non-magnetic material. Also, the left f and lI tank walls 4a and ? The O-regulating rod 6 and the doctor blade 7, to which the secondary regulating part formed as the doctor blade 7 is fixed, extend parallel to the sleeve 2 and extend over almost the entire length of the sleeve 2. It extends between the regulating rod 6 and the lid blade 7 and the sleeve 1 and the knob 2.
Then, there is a predetermined minute gap gt+g2force i]-r-. Among the plurality of magnets installed in the sleeve 2, the stones 6b, which are shown with reference numerals 3a and 3b in FIG. Ru. However, accurate (・ means these magnets 3
a, 3 1) magnetic poles 8, 9, 7, rad 7, and regulating rod 6 are not completely oriented 4,
They are slightly shifted in position and facing each other, but details regarding this will be explained later. In the description of the book, one of the magnets 3a and 3b may be replaced with the first magnet 3a, if necessary.
The ten magnetic poles 8 of the magnets are called the first sharpened pole, and the other magnet 3b is called the second M! The magnetic pole 9 of the L stone will be referred to as the second magnetic pole. lOC is an agitator that rotates in the direction of arrow A within the tank 4.

In the printer shown in FIG.
lf body f. - The photoreceptor 11 is formed into an endless belt shape,
This photoreceptor 1] has a drive roller 12 shown in the figure, a drive roller 12 shown in the figure,
, τ are wound around an externally powered roller and driven in the direction of arrow B. Instead of a belt-shaped photoreceptor,
Of course, a drum-shaped or sorted photoreceptor may also be used.

When the recording operation starts, the sleeve 2 is moved counterclockwise by 1.
The agitator 10 is driven in the direction of arrow A.

At this time, the developer 5 located in a relatively low part of the tank 4 flows between the tank wall 4b on the right side in the figure and the regulating frame 6 as shown by an arrow C1, and reaches the surface of the sleeve 2. Supplied. In addition, the developer is attracted to the surface of the sleeve 2 by the magnetic force of the magnet, and the developer is attracted to the surface of the sleeve 2 by the magnetic force and the sleeve 2.
A counterclockwise conveying force is applied by the cooperation with the rotation. When this developer is about to pass through the gap g1 between the regulating frame 6 and the sleeve 2, the amount of developer transported is regulated by the regulating frame 6, and a predetermined amount of developer determined by the size of the gap g is regulated. Pass under the bar.

The developed image 11 whose amount has been regulated in this manner is carried by the sleeve 2 and is conveyed in layers (arrow C2) until it reaches the area r where the doctor blade 7 is located (and the blade...
A predetermined amount of developer passes through the gap g2 between the sleeves (arrow C3), and the developer that has passed under the doctor blade 7 forms a thin layer 5a on the sleeve 2 and is completely conveyed over the sleeve 2, and is then transferred to the photoreceptor 11. The area facing the sleeve 2, that is, the developing area D4C is reached.

The developer that does not pass under the doctor blade and is scraped off by the blade 7 hits the doctor blade 7 or the tank wall 4a located near it, and is pushed upward in the figure, as indicated by arrow C4. Return to the Dobe area of Tank 4 again as shown in Figure 2, and agitator I
OK, so it is sent in the F) If arrow C1 direction. However, in the configuration according to the present invention, a portion of the developer returned to the upper region of the tank 4 is indicated by the arrow 0. The fluid rotates as shown in the figure, and this will be explained later.

On the other hand, the photoreceptor 11 is rotated and driven in the direction of arrow B, and at this time, an electrostatic latent image is formed on the thorny surface of the photoreceptor by a latent image forming device (not shown), and the latent image is moved as the photoreceptor moves. Accordingly, it is brought to the development area described above. At this time, the developer, especially the toner, that has reached the development area DK electrostatically adheres to the latent image.
The latent image is transferred to a transfer paper (not shown) as is well known.The developer passes through the development area I without transferring to a latent image. is then transported counterclockwise and returned to tank 4. At this time, as described above, the developer flowing in the direction of the arrow C1 and completely supplied to the surface of the sleeve 2 and the developer returned to the tank 4 are stirred.

As mentioned above, in the illustrated four developing devices, the tank 4
The amount of developer contained in the tank 4 is roughly regulated by a regulating frame 6, which is a primary regulating member, and its layer thickness is then regulated by a doctor blade 7. Therefore, the amount of developer sent to the doctor blade 7 does not become excessive as in the case without the regulation frame 6, and deterioration of the developer can be suppressed. However, in conventional devices of this type, as briefly explained above, there is a risk that developer may accumulate in the vicinity of the doctor blade 7, for example in the area designated by the symbol X2 in the figure. This is because some of the developer that was not pushed upward without passing through the gap g2 reaches the doctor blade 7.
The developer is pressed against the tank wall 4a, and this developer is transported one after another in the direction of arrow C2. This phenomenon is thought to occur because of the According to experiments, when the printing operation was performed about 20,000 times, some developer that did not move was formed in the region It turns out that it was.

As a result of repeated studies on the causes of the above-mentioned defects and their countermeasures, the inventor has discovered the following new fact.

First? For the sake of simplicity, the first and second magnetic poles 8 described above in the moving direction (rotation direction in this example) of the sleeve 7
, 9, and the centers of these widths WI + W2 in the sleeve rotation direction are the first and second
Center E1. We will call it E7.

In this case, when the magnet or the rod is used as in the specific example shown in FIG. The second center EI+E2 is 1°, which is assumed to coincide with the width and center of each magnet 3a, 3b in the direction of rotation of the sleeve.
1. The direction of movement of the sleeve (also the direction of rotation in this example) is defined as positive, and the opposite direction is defined as negative, and the center of the width W3 of the regulating frame 6 in the direction of rotation of the sleeve is defined as the third width center E3. 1. The first normal F of the sleeve surface passing through the center EI
1 and the second v-th normal F2 of the sleeve surface tracing to the second center E2'.

In this example, since the regulation frame 6, which is the primary regulation member, is made of a round bar-shaped member, the third center E coincides with the axial center of the regulation frame 6.

The structure of a conventional developing device having a primary regulating member and a secondary regulating member will be briefly described with reference to FIG. 1
Moreover, the inner surface of the tank 4 of the doctor blade 7, that is, the surface 7a in contact with the developer 5 in the tank was located at the second modulus iFz1. However, as a result of repeated various experiments, it was found that positioning each element in this way was the main cause of the developer pooling, or its aggregation and assimilation phenomenon, as explained earlier. It became clear that The present invention is based on this new recognition, and in the embodiment shown in FIG. 1U, the third center E3 is located on the negative side of the first normal line Do1 by an angle θ1 , Moreover, the surface 7a of the doctor blade 7 is at an angle θ of 1°M2r from the second normal.
Also, each element 3a, 3b is positioned on the negative side
, fi, 7 are determined. With this configuration, it is possible to effectively suppress the inconvenience that the developer accumulates in the above-mentioned region X VC and coagulates and solidifies. That is, the developer scraped off by the doctor blade 7 does not accumulate in the region
It rises along d. However, the theoretical basis for this configuration has not yet been clarified as to why developer retention can be reduced. However, when conducting experiments, as explained earlier, It has been observed that part of the developer pushed up to the top of the screen rotates and flows as shown by arrow C5, and this is presumed to be a factor in preventing the developer from stagnation (as compared to the conventional configuration). (In this case, such rotational flow of the developer is not clearly recognized.)

Similarly, through experiments, the deviation angles θ and θ2 were set to 0〈
θ1≦15°, 0≦θ2≦15°, 1st position In addition, when the developer carrier is a cylindrical sleeve 2 as in the illustrated example, the angle formed by the first modulus a FI and the second modulus a P2 θ, 50°
Also confirm that it is advantageous to set it to 70°.
By the way, it goes without saying that the primary regulating member can be formed in various shapes other than round bars. At this time, in the embodiment shown in FIG. 1, this primary regulating member is configured as a round bar-shaped regulating frame 6, so that almost the entire regulating member functions to regulate the amount of developer conveyed. become. However, for example, when the cross section of the primary regulating member 6 is shaped like a letter 7 as shown in FIG.
Only the portion 6a facing 1 functions to effectively regulate the amount of developer conveyed, and the other portion 6b does not substantially perform parent control of the developer. When bending, the width w3 and the center E3 of the primary regulating member are the same as the regulating member 6.
It goes without saying that the width and center of the effective regulating portion 6a in the direction of rotation of the sleeve should be considered (FIG. 2). The same applies when the primary regulating member has a shape other than that shown in FIG.

- It is not necessary to arrange the entire part 7a of the doctor blade 7 on the side that contacts the developer in the tank on the negative side of the second normal F, and at least It is sufficient to place a part of it on the negative side of the second normal F2.

Furthermore, as shown in FIG. 2, it is sufficient if the doctor blade 7 is constituted by the wall of the tank itself. Similarly to the case shown in Fig. 1, when the grooved sleeve 2 has a roller-shaped magnet as shown in Fig. 2,
By positioning each element 7, 8, 6.9, the conventional drawbacks can be reduced (in the case of the second [ゝZ:, the center E1 of the first magnetic pole 8 and the second magnetic pole, 9. E2 is
It is natural to consider the center of each magnetic pole 8, 9 itself, not the center of the magnet.)

Next, the progress of the experiment conducted using the printer shown in FIG. 1 will be briefly explained.

As the developer 5, a one-component developer containing a toner with a relatively high specific volume resistivity and magnetic fine particles that can transfer the latent image during development was used (a developer containing such magnetic fine particles) was used. J. (sometimes referred to as a five-component developer). The developer used in the experiment is a type of developer suitable for thermally fixing the visible image transferred onto the transfer paper.

A developer end sensor (not shown) is attached to the tank 4 to detect when the developer runs out. As the regulating rod 6, a bar material made of a non-magnetic brass and having a diameter of 10 was used. The sleeve 2 was made of 11E [B-type stainless steel, but of course aluminum or the like may also be used], and its outer diameter was 36 mm. sleeve 2
Among the magnets 3 disposed inside the magnet 3, a bar magnet having a groove 3c in the center and having its north pole facing the photoreceptor was used as the main magnet facing the photoreceptor 11. The photoreceptor II is a belt having a photosensitive layer of an organic semiconductor on the surface C, and the drive roller 12 for the photoreceptor has an outer diameter of 25φ, which is smaller than the normal drive L]-ra. . For this reason, the width of the developing area (the length of the developing area in the circumferential direction of the sleeve) is also narrow, approximately 1/'2 of the width M of a general copying machine (11!). ′. The gap between the blade 7 and the sleeve 2 (Tt was about 0.3 to 0.5 mm. Also, the first normal line 1"
1 and the second normal line B2o is 6oO1 deviation angle θ1. Both θ2 were set to 7°.

When the above-described developing operation was repeated under the above 811 conditions, there was very little developer accumulation in area X, and the deterioration in visible image quality that was conventional could be suppressed. The problem is that the developer that has risen along the wall surface 7a of the frame 7 is removed from the intator 1 (N), so that the detergent at the top of the tank 4 is effectively agitated. This is thought to be due to insufficient supply of the developer to the surface of the sleeve 2.In this way, in order to prevent the deterioration in the image quality of the cleaning agent mentioned above, the developer in the tank 4 is completely replaced with new developer. The trouble of having to replace the developer can be avoided or reduced, and simply replenishing the tank 4 with developer is sufficient for a long period of time.

Although advantageous embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways.

For example, in the illustrated developing rW device, a sleeve is used as the developer carrier, but the present invention can also be advantageously applied to a developing device that uses a belt as the carrier. Furthermore, instead of the developing device in a laser printer, for example, the developing device in an electrostatic recording device equipped with a latent image carrier containing a dielectric, the image device in an electronic copying machine, or the latent image carrier is the final recording material. The present invention can also be applied to a developing device of a so-called direct copy recording device used for sorting.The third center E3 is placed closer to the sacral side of the first normal F. However, even if only one of these two conditions is satisfied, the intended purpose of the present invention can be achieved, and the same applies when the present invention is applied to a developing device other than that shown in the drawings. This can be said to be true.

As can be understood from the above description, the present invention can achieve its intended purpose with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a developing device according to the present invention, and FIG. 2 is a sectional view showing another embodiment of the developing device.

Claims (1)

[Scope of Claims] (]) A rotatably supported ζa, a developer carrier, a tank for accommodating the developer, and a layer thickness of the developer on the developer carrier existing in the tank, which is The primary regulatory department that regulates
Secondary regulation of the layer thickness of developer that can be carried out of the tank 2
a secondary regulating member; and first and second G poles that are disposed within the developer carrier and are located substantially opposite to each of the primary and secondary regulating members, and the developer is transported out of the tank. In a dry developing device that visualizes a 1-1 image formed on a latent image bearing member by a developer), the centers of the first and second magnetic poles in the moving direction of the developer bearing member are and the width of the effective regulating portion of the primary regulating portion in the moving direction of the developer and the carrier, where the moving direction of the developer carrier is positive and the opposite direction is negative. The center is located on the negative side of a first normal line of the surface of the developer carrier including the first center, and at least one of the surfaces of the secondary regulating member that contacts the developer in the tank. or a second normal to the surface of the developer carrier including the second center;
The dry developing method is characterized in that the positions of the first and second magnetic poles and the primary and secondary regulating members are respectively determined so as to satisfy at least one of the two conditions. Device. (2) The dry development according to claim 1, wherein the developer carrier is a sleeve, and the first normal line and the second normal line form an angle of 50° to 70°. Device.