JPS6027406Y2 - Wet developing device - Google Patents

Description

[Detailed description of the invention] This invention enables faster development of charged latent images, which is insufficient only by contact with the developer attached to the surface of the developing roller, in an apparatus using a wet developer. This invention relates to a wet-type developing device that has been improved to achieve the following.

2. Description of the Related Art Conventionally, devices using liquid developers have been put into practical use when visualizing a latent charge image formed on a recording paper surface.

This type of device is equipped with a developing roller with a cylindrical part immersed in developer, and by rotating the developing roller, the developer is drawn up in a thin film form on the roller surface, and the recording paper is placed on the developing roller surface. The recording paper is brought into contact with a thin film of developer drawn up by rubbing, and development is performed.

In order to sufficiently develop the charge latent image to a saturated state, it is necessary to increase the time during which it is in contact with the developer.

Therefore, conventionally, a counter electrode plate is installed on the rotation direction side of the developing roller, and the developer drawn up by the rotation of the developing roller is spread over the counter electrode plate, and after contact with the roller surface, the developer on the counter electrode plate is developed. Wet development has been attempted in which the surface of the recording paper is brought into contact with the liquid.

However, even if the contact time with the developer is increased by using the counter electrode plate, it is difficult to say that fresh developer is smoothly supplied to the contact surface of the recording paper.

In other words, the surface of the conventionally used counter electrode plate is formed to be smooth, so when the recording paper passes through, the gap between the counter electrode plate and the recording paper is pinched by the weight of the recording paper, and the developer flows through this gap. In this case, a very large sheet resistance occurs, and due to this sheet resistance, the developer drawn up by the developing roller is returned to the developer tank without being injected onto the counter electrode plate. There was a fear that the function of the system would not be able to achieve its intended purpose.

The present invention eliminates the drawbacks of the above-mentioned conventional apparatus and provides an apparatus capable of obtaining high-speed and high-performance development with a sufficient supply of developer.The present invention will be explained in detail below with reference to the drawings. do.

In FIG. 1, reference numeral 1 denotes a developing tank for storing a developer 2, and a developing roller 3 is provided in the developing tank 1 with a part of the roller surface immersed in the developer 2. By rotating in the direction of the middle arrow, the developer 4 is drawn up in a thin film form.

A counter electrode plate 5 is installed above the developing roller 3 in the rotational direction with its tip abutting against the roller surface.

The counter electrode plate 5 has the upper surface thereof further supplied with the developer 4 drawn up by the rotation of the developing roller 3, and serves to expand the range in which the recording paper 6 comes into contact with the developer.

That is, the plane formed by the upper part of the developing roller 3 and the counter electrode plate 5 forms a part of the conveyance path of the recording paper 6, and the recording paper 6 on which the electrostatic latent image is formed is conveyed by a pair of feed rollers and pinch rollers (not shown). ), etc., onto the developing roller 3, and is brought into contact with the drawn-up thin film developer 4 to be developed.

Following contact with the developing roller 3, the recording paper 6 is further conveyed and sent onto the counter electrode plate 5, where it comes into contact with the developer spread on the plate and is sufficiently developed to a saturated development state. Ru.

Here, in order for the recording paper 6 to be developed efficiently and with high performance, it is necessary that fresh developer 4 be drawn up by the developing roller 3 and sufficiently supplied onto the counter electrode plate 5. .

The developer once pumped up to the top of the developing roller 3 leaks from the gap at the contact area between the circumferential surface of the four-force button roller and the counter electrode plate, and is returned to the developer tank 1 without reaching the counter electrode plate. Otherwise, the efficiency will decrease.

Therefore, the tip of the counter electrode plate 5 is finished into an acute angle shape so that it can come into butt contact with the roller surface.

However, the opposing electrode plate 5 and the developing roller 3 are usually made of a rigid body such as metal, and it requires advanced technology to finish the entire developing width of the opposing portion to prevent leakage of the developer. It's not practical.

Further, if the two are strongly pressed against each other, rotational load will be added, which will not only burden the device and cause noise, but also may cause uneven development due to abnormal rotation of the developing roller 3.

Therefore, a flexible sheet 7 made of plastic or the like is bonded to the main body portion of the opposing electrode plate 5 made of a rigid body and the tip portion that contacts the developing roller 3. By being in pressure contact with the circumferential surface of 3, leakage of the developer is prevented, and the problem of processing accuracy is also solved.

Further, when the surface of the counter electrode plate 5 is finished smooth, the developer pumped up as in the conventional apparatus described above is not deposited on the counter electrode plate 5 due to the sheet resistance between the recording paper and the counter electrode plate. There is a risk that the water will not flow in and will be returned to the tank 1.

For this purpose, a large number of concave grooves 8 are formed on the surface of the counter electrode plate 5, as shown in FIG. 2, which are continuous in the direction in which the recording paper travels.

Therefore, even if the recording paper 6 comes very close to the counter electrode plate 5, the liquid can be supplied through the groove 8, and the recording paper 6 that is close to it is pushed upward by this liquid supply pressure.
The liquid is also supplied to the convex portions around the grooves, and the entire surface of the recording paper comes into contact with the developer.

In addition to the above example, the groove shape on the surface of the counter electrode plate is
Various shapes can be adopted, such as a cross groove shape as shown in FIG. 3A, a wavy groove shape as shown in FIG. 3, and an oblique groove shape as shown in FIG.

Further, the convex portion between adjacent grooves can be designed to have any shape such as a mountain shape, a trapezoid shape, etc. even if the top portion is flat.

Furthermore, the pitch between the grooves, the dimensions of the groove bodies, etc. can be changed as appropriate depending on conditions such as the liquid pumping ability of the developing roller 3 and the recording paper conveyance speed.

The smaller the distance between the recording paper and the developing electrode, the stronger the electric lines of force, and the more strongly the developer particles can be attracted to the charged recording paper, resulting in high-speed, high-performance development. Since there is a convex part between the grooves,
High-speed, high-performance development can be achieved by reducing the distance from the recording paper.

The developer that has flowed onto the counter electrode plate 5 is swept away from the other end on the opposite side where it comes into contact with the developing roller 3 and is returned to the developer tank 1 again.

In the figure, reference numeral 9 denotes a rear regulating plate provided on the recording paper conveyance path, which prevents the recording paper 6 from floating up.

As described above, according to the present invention, a counter electrode plate is installed at the next stage of the developing roller, and by forming a concave groove continuous in the recording paper transport direction on the upper surface of the counter electrode plate, even if the recording paper is Even if they are very close to each other, fresh developer can be supplied to the recording paper surface by the liquid supply pressure to the groove, and uneven development can be prevented and high quality development can be obtained.

Also, since the developing efficiency of the recording paper on the counter electrode plate is improved,
It is possible to achieve even higher speeds.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of the present invention, FIG. 2 is a plan view of the same embodiment, and FIGS. 3 a, b, and c are plan views showing other embodiments of the main parts of the present invention. . 1: developer tank, 3: developer roller, 4: thin film developer, 5:
Counter electrode plate, 6: recording paper, 7: flexible sheet, 8: groove.

Claims (1)

[Scope of utility model registration request] A rotating developing roller partially immersed in developer, a developing electrode facing the developing roller at one end and extending in the conveyance direction of the recording paper on which a latent charge image has been formed, and the developing electrode itself. A wet type developing device comprising a concave portion formed continuously along the conveying direction of the recording paper on the upper surface thereof, through which the developer drawn up by the developing roller is passed.