JPH0447832B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drying method designed to speed up the drying process and to prevent uneven drying when developing an electrophotographic light-sensitive material using a liquid developer.

In a so-called wet electrophotographic recording (or copying) system that develops an electrophotographic light-sensitive material using a liquid developer, charging, exposure,
After going through the five-stage processing process of development, drying, and fixing, the image information is recorded on microfilm, etc.
Or be copied. That is, the surface of the electrophotographic light-sensitive material is first charged by corona discharge or the like in a charging step. Next, in an exposure step, the image information to be recorded is exposed onto the electrophotographic light-sensitive material through a lens or the like to form an electrostatic latent image. is sent to a developing process, where a liquid developer is applied to the photosensitive surface. As a result, depending on the pattern of the electrostatic latent image,
Toner is supported on the photosensitive surface by Coulomb force. After that, the electrophotographic photosensitive material is sent to a drying process, where the welding of the liquid developer is dried and removed, and then, as a fixing process, the toner electrically supported on the photosensitive surface is heated, pressurized, or coated with a resin. established by As a result, image information is permanently stored on the surface of the electrophotographic material.

As described above, in a recording system using electrophotography, all the processing up to development and fixing proceeds every time one piece of image information is exposed, so there is an advantage that the image information can be immediately reproduced. Additionally, since the photoreceptor is not sensitive to light until it is charged, it has the advantage that it does not need to be completely shielded from light when the photoreceptor is being stored or being projected using a reader. Recording by electrophotography has begun to be put to practical use not only in the field of so-called copying machines but also in the field of microfilm systems.

By the way, in the above-mentioned electrophotographic recording system, since toner is electrically supported on the photosensitive material before fixing, it is necessary to fix the toner immediately after exposure and development. Further, when the electrophotographic light-sensitive material is a film used for recording a large number of frames, such as a roll film or a flash film, it is necessary to sequentially perform the above-mentioned processing steps for each frame. In this case, the problem is that the liquid developer does not leak out to places other than the electrophotographic light-sensitive material or to frames other than the frames to be developed, and that the liquid developer does not leak from the top of the photosensitive surface until fixing. The solvent in the developer must be sufficiently dried and removed. If the fixing process is performed with the solvent remaining on the photosensitive surface, the fixing quality will be affected, such as heat fixing causing blistering on the photosensitive surface, pressure fixing causing the toner to flow, and coating fixing causing the resin not to harden. Getting worse. Therefore, it took a relatively long time to dry the solvent.

In order to solve these problems, a developing processing apparatus as shown in FIG. 1 has been proposed. In general, if the part that undergoes development processing is formed independently from the parts that undergo other processing, it is called the development head, and if it is formed integrally with the part that undergoes other processing, it is called the development section. It is often called.

In FIG. 1, 1 is a developing head or developing section, and its opening 12 is a developing chamber. Developing chamber 1
2 is surrounded by a developing mask 2, and the photosensitive surface side of the electrophotographic photosensitive material 3 is tightly attached to the end surface 2b of the opening frame 2a by a presser plate (not shown) or the like. The inner peripheral shape of the opening frame of the development mask 2 is a shape that limits the area to be developed, for example, the area for one frame of the electrophotographic photosensitive material. There are an inlet and an outlet, that is, a developer inlet 5, a gas inlet 6, and an outlet 7.
The liquid developer 4 in the developer tank 8 is fed to the developer inlet 5 by a developer pump 13, and a certain amount of the liquid developer is sprayed onto the electrophotographic photosensitive material 3 after exposure. An electrode that faces the photosensitive surface of the electrophotographic photosensitive material and assists in electrically supporting the toner in the liquid developer on the photosensitive surface. A portion of the liquid developer sprayed onto the electrophotographic photosensitive material flows down the photosensitive surface and returns to the developer tank 8 through the discharge port 7. When the supply of the liquid developer is completed, that is, the development is completed, a gas such as air is flowed into the developing chamber 12 from a blower pump or a gas cylinder (not shown) through the gas intake port 6 using the valve 16, and the electrophotographic photosensitive material is The solvent of the liquid developer on the photosensitive surface of No. 3 is evaporated, and the liquid developer attached to various parts such as the inner wall of the developing chamber 12 is blown away. At the same time, the suction pump 15
The electrophotographic photosensitive material 3 and the developing mask 2 are activated.
The liquid developer that has entered the space between the end faces 2b of the opening frame is sucked. This suction is continued until the electrophotographic photosensitive material 3 is sent to the next drying process, and when the electrophotographic photosensitive material 3 separates from the aperture frame end face 2b, most of the liquid held therebetween is sucked. Note that 9 is a suction slit, 10 is a suction port, and 14 is a trap.

In this way, the electrophotographic photosensitive material 3 is placed in the developing chamber 12.
By squeezing the liquid in advance while the product is still in storage, the drying process in the next step can be completed in a short time.

Conventionally, it has been considered preferable to drain the liquid as completely as possible in the development process. FIG. 2 is a graph of the amount of liquid remaining on the electrophotographic photosensitive material versus the time of air blowing from the gas intake port 6. However, the electrophotographic photosensitive material is a 16 mm microfilm, and the opening of the developing chamber 12 is 10 mm square. In FIG. 2, curve A shows the characteristics when only air is blown without suction, and curve B shows the characteristics when air is blown and suction is applied at the same time.

However, as can be seen from FIG. 2, the amount of liquid on the photosensitive surface decreases significantly within one second after the start of air blowing or air blowing and suction, but the amount of liquid hardly decreases during this transition. The reason for this is that the liquid held between the electrophotographic photosensitive material 3 and the opening frame end surface 2b of the development mask is not completely removed regardless of whether suction is applied or not.

On the other hand, if the air blowing continues for a long time, for example, 2 seconds or more, the electrophotographic photosensitive material 3 facing the inside of the developing chamber 12 begins to be partially dried. If an attempt is made to proceed to the drying process in such a partially dried state, when the electrophotographic photosensitive material 3 separates from the opening frame end surface 2b of the development mask, the liquid held during this time flows out onto the drying surface. Since it will then be re-dried,
Uneven drying occurs and the quality of recorded images deteriorates.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drying method for electrophotographic liquid development that eliminates the problems of the prior art and speeds up the drying process while preventing uneven drying.

The structure of the drying method of the present invention that achieves this objective is that a development mask in a developing chamber is brought into close contact with the electrophotographic photosensitive material after exposure, and a liquid developer is supplied to only a limited area for development. Gas is flowed into the developing chamber while the developing chamber is in close contact with the developing mask, and the liquid is drained until a liquid film of the liquid developer remains on the entire surface of the limited area. The electrophotographic material is relatively moved from the developing chamber to the drying chamber while the electrophotographic material remains on the entire surface of the liquid developer, thereby drying the region wetted by the liquid developer.

That is, by supplying the liquid developer with the development mask in close contact with the electrophotographic photosensitive material, the liquid developer is prevented from leaking to areas other than the photosensitive surface. In addition, the time required for drying can be shortened by draining the electrophotographic material by flowing gas while the electrophotographic material is in the developing chamber. Furthermore, by limiting the amount of liquid developer that remains on the entire surface of the liquid developer, even if the liquid held between the developing mask and the electrophotographic photosensitive material flows out when the electrophotographic photosensitive material is transferred to the drying chamber, , since the entire surface is still wet with liquid developer, uneven drying does not occur.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic perspective view of a microfilm process head that integrates processing steps from exposure to fixing. In the figure, 20 is a charging/exposure section, 1 is a developing section, 25 is a drying section, and 28 is a fixing section. part, 32 is 16
32a is a blip mark, and 33 is a blip mark detection sensor. Figures 4a to 4d show the cross-sectional structure of each part. Fourth
Figure a shows a cross section of the charging/exposure section 20, and in the figure, 2
1 is a corona wire, 22 is a side electrode, 23 is a lens, and 24 is a film holding plate. Figure 4b
1 shows a cross section of the developing section 1, the details of which are the same as in FIG. FIG. 4c shows a cross section of the drying section, in which 26 is a drying chamber and 27 is a drying gas intake port. FIG. 4d shows the fixing section, in which 29 is a xenon lamp, 30 is a glass plate, and 31 is a suction port.

FIG. 5 shows an example of the processing order when the integrated process head of FIG. 3 is used. #1 in the diagram
#4 is the frame number of the film 32. Now, if we focus on frame #1, we see that film 3 is in the charging/exposure section 20.
2 and press it down with the presser plate 24, charge it in the first 1 second, and finish the exposure in the next 3 seconds. Next, the holding plate 24 is removed and the film 32 is sent to the developing section 1 for 0.5 seconds, and the developing pump 13 is operated for about 1.5 seconds to apply the liquid developer 4 to the film 32. In this state, the #2 frame is designed to be located in the charging/exposure section 20, and photography is performed as necessary. Next, before moving the piece, air is blown to the #1 piece for about 1 second. The amount of air blown in this case is about 5/min. Although the amount of residual liquid is less than 0.5 mg/piece, a liquid film remains on the entire surface, making it wet. After draining the liquid with the entire surface wet, the holding plate 24 is released, the film 32 is fed one frame, and the #1 frame is transferred to the drying chamber 26. A drying gas such as air is passed through the #1 piece for about 5 seconds to completely dry it. In this case, the opening of the drying chamber 26 is such that the film 32 is located at the end surface of the opening frame of the developing mask.
In order to also dry the portion in contact with b, it is desirable that the opening frame be larger than the opening frame of the development mask. Since the #1 piece was transferred to the drying chamber 26 while its entire surface was wet with liquid, it was dried evenly. While the #1 frame is drying, the #2 frame is developed and drained, and the #3 frame is charged and exposed. Next, the film 32 is advanced by one frame, and frame #1 is heated for a short time by a xenon lamp 29 in the fixing section 28 to be fixed. Thereafter, pieces #2 and subsequent pieces are sequentially processed in the same manner. Air is blown for one second just before the film is moved to drain the liquid, but this may be done at any time after development and before the film is moved. Further, although suction is performed between blowing and moving, it is not necessary to limit the suction to this, and it is also possible to perform the suction continuously, for example.

Although the film 32 is moved in the above embodiment, the same applies to the case where the film is fixed and the process head is moved. The same applies when the developing section, drying section, etc. are not integrated but are independent. Further, in the case of a special liquid developer, the toner is fixed only by a drying process without performing a fixing process, and the present invention can also be applied to this case. Furthermore, as disclosed in JP-A-53-76035, the present invention is also applicable to electrophotography in which positive images and negative images are selectively obtained by double charging in forward and reverse directions, followed by exposure and then recharging and uniform irradiation. can be applied.

[Brief explanation of the drawing]

The figures relate to the present invention; FIG. 1 is an explanatory diagram of the structure of the developing head or developing section, FIG. 2 is a graph of residual liquid amount versus air blowing time, FIG. 3 is a schematic perspective view of the integrated process head, and FIG. 4 A to d are cross-sectional views of each part in FIG. 3, and FIG. 5 is a diagram showing an example of a processing procedure. In the drawing, 2 is a developing mask, 3 is an electrophotographic photosensitive material, 4 is a liquid developer, 6 is a gas intake port, 9 is a suction slit, 12 is a developing chamber, and 15 is a suction pump.

Claims (1)

[Claims] 1. After exposure, the electrophotographic light-sensitive material is brought into close contact with the development mask in the development chamber, and a liquid developer is supplied to only the limited area for development. By flowing gas into the chamber, the liquid developer is drained until a film of liquid developer remains on the entire surface of the limited area, and the electrophotographic material is processed while the film of liquid developer remains on the entire surface of the limited area. A drying method for liquid development in electrophotography, characterized by drying an area wetted by a liquid developer by relatively moving it from a developing chamber to a drying chamber.