JPS59116670A - Electrophotographic developing head - Google Patents

Abstract

PURPOSE:To simplify the structure of a carrying system where a liquid toner is sprayed to a photosensitive face, by providing the first flow passage through which only the toner passes, the second flow passage through which only a gas passes, and a valve which closes the second flow passage when the toner is sent with pressure. CONSTITUTION:A mask 12 of a body 11 of a developing head has an aperture 12a having a size corresponding to a farme to be developed of a photosensitive material 13, and a liquid toner 14 is sprayed through this aperture 12a to develop a latent image, and air is sprayed to a photosensitive face 13a after development to squeeze the toner. The liquid toner 14 is sucked from a tank 15 by a pump 16 and is carried from the first flow passage 18 through a valve 17. The first flow passage 18 is connected to the second flow passage 19 by the valve 17, and the air pressure-feeding from the second flow passage 19 is stopped by the valve 17 when the toner 14 is fed with pressure, and air carried from the second flow passage 19 by an air pump 20 is sent to the aperture 12a through the valve 17 when the toner 14 is not fed with pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing head for an electrophotographic apparatus, and is intended to simplify a mechanism for spraying liquid toner and for removing liquid toner.

Unlike photographic films that use silver salt photographic materials as photoreceptors, electrophotographic materials take advantage of the characteristic that they can be reused by cleaning them after development and before fixing, regardless of whether they are exposed or not. A long roll film is used as the material, and it is partially charged, exposed, developed,
It is used for microfilm, etc., in which an image is recorded by fixation, and the resulting image is used for purposes such as projection, along with unrecorded parts, and then new records are added to the unrecorded parts. ing.

Among electrophotographic devices using microfilm as described above, so-called wet-type electrophotographic devices that develop electrostatic latent images with liquid toner perform charging, exposure, development, drying, and fixing for each frame. During the development process, it is preferable that toner not overflow or ooze out of areas other than the area of the photosensitive material to be processed, and excess developer solution should be removed before the photosensitive material is separated from the developing section and transferred to another processing section. Remove the liquid drainer (
(hereinafter referred to as "squeeze")).

Here, a conventional electrophotographic apparatus using a wet type vacuum pump will be described with reference to FIG. As shown in the figure, there is a mask 2 on the body 1 of the developing head in this building.
The mask 2 has an opening 2a having a width corresponding to one frame of the photosensitive material 3, and the opening end 2b is in contact with the photosensitive material 3. As a result, the photosensitive breakfast material 3
The photosensitive surface 3a for one frame faces the opening 2a, and a predetermined latent image is developed by spraying liquid toner 4 onto the photosensitive surface 3a through the opening 2ai. Following this development, it is necessary to squeeze the toner 4 adhering to the photosensitive surface 3a.
(This is done by blowing a gas such as air onto the photosensitive surface 3a through i7. Therefore, it is necessary to transport the liquid toner 4 and the gas (air in this example) to the full opening 2a. In the charging process, the toner 4 stored in the tank 5 is sucked up by the vacuum pump 6, and when the valve 7 is opened, the air is sucked in from the air by the vacuum pump 6.In other words, the toner 4 stored in the tank 5 is sucked up by the vacuum pump 6. A flow path 8 that reaches the inside of the body, passes through the opening 2ai, reaches the outside of the bodyier, passes through the entire vacuum pump 6, and returns to the tank 5, and from the end open to the atmosphere passes through the valve 7 to the inside of the body 1.
A flow path 9 that joins the flow path 8 is formed upstream of the opening 2a.

In FIG. 1, reference numeral 10 denotes a developing electrode, which faces the photosensitive surface 3a to increase the overall development speed and obtain a good image with little edge effect.

Thus, in the developing head of this type of electrophotographic apparatus, after developing the photosensitive surface 3a by spraying the toner 4 and squeezing,
However, since the development head uses a vacuum pump 6 as a conveyance system for the toner 4 and squeeze gas, the structure of this part is complicated. It has become a thing. Alternatively, a system in which the toner is force-fed using a liquid pump or the like without using a vacuum pump can be considered, but the space between the photosensitive surface 13a in the developing area and the developing electrode IO is usually quite narrow, and the viscosity of the toner causes liquid resistance, causing the toner to flow. (ri, it becomes easy for the toner to get into the gas conveyance pipe. At this time, if the toner gets into the gas conveyance pump, it will cause trouble, and even if it just gets into the pipe, the gas conveyance pump will not work.) When this process is started, the toner that has entered the tube is blown out into the developing chamber, reducing the efficiency of squeezing.

The present invention solves the above-mentioned problems and improves the structure of the transport system.
It is an object of the present invention to provide a developing head for an electrophotographic apparatus that can fully measure the development of the electrophotographic material. While spraying liquid toner on the surface,
Similarly, in a developing head of an electrophotographic apparatus in which the toner is sprayed with the full opening valve and the toner is drained by spraying gas onto the photosensitive surface, there is a means for pumping the toner, and a means for pumping the gas completely. , a first channel through which toner exclusively passes, a second channel through which gas exclusively passes, and the second channel 1-I-i is completely closed when toner is pumped, and when the gas is pumped, the second channel is closed. It is characterized by the provision of a valve that opens completely, and the toner is pumped into the gas conveyance pipe by %1.
The basis of its technical philosophy is the provision of a valve to prevent 7k.

Embodiments of the present invention will be described in detail below based on the drawings. As shown in FIG. 2, the body 11 of the developing head of this embodiment
The LC mask 12 is also provided as in the prior art, and this mask 12 has an opening 12ai of a width corresponding to the frame of the photosensitive material 13 to be developed, and the opening end 12b is in contact with the photosensitive material 13. ing. As a result, the photosensitive surface 13a of one frame of the photosensitive material 13 faces the opening 12a, and the liquid toner 14 is sprayed through the opening 12ai.
Due to aging, a predetermined 1' image is formed in total 3M+y, and after this development is completed, air is similarly blown onto the photosensitive surface 13a to perform squeezing. 1st class: l! ;'r 1
Reference numeral 8 has one end open to a tank 15 in which toner 14 is stored, and exclusively transports the toner 14 pumped up by a pump 16 interposed in the middle. As the pump for pumping the toner, known pumps such as an emperor pump, a gear pump, and a vane pump can be used.

On the other hand, the second flow path] 9 has one end open to the atmosphere,
The air pump 20 interposed in the middle exclusively transports the air sucked in. It's cool, these first flow paths 1
8 and the other end of the second flow path 19 are both connected to the valve 17 . This valve 17 is also connected to the inlet of the third flow path 21 communicating with the opening 12a, and closes between the second flow path 19 and the third flow path 21 when the toner 14 is pumped. At the same time, when the toner 4 is not pumped, the second
The flow path 19 and the third flow path 21 are opened. This box 17 prevents the toner from going around into the gas conveying pipe, thereby achieving good development and squeezing.

FIGS. 3(a) to 3(e) show a more detailed structure of the valve j7. The valve 17 shown in the third step a) is...
A ball 17c is placed in a chamber 17b formed in the housing 17a.
The first flow path 18, the second flow path 19, and the third flow path 21 each serve as a three-way valve that communicates with the chamber 17b. Thus, when the toner 14 is pumped, that is, the pump 16
When driving, the ball 17c is pushed by the toner 14 and moves to the right in the figure, and the second flow path 19 is fully closed.
When the toner 4 is not being pumped, that is, when the air is being pumped by the air pump 20, the ball 17c is pushed by the air and moves to the left in the figure, and the second flow path 19 is fully opened. The flow path 18 is closed. The valve 17 shown in FIG. 3(b) has a thin plate-shaped valve body 17f disposed at the opening of the second flow path 19 in the chamber 17e formed in the /1 housing 17d. Second flow path 19 and third flow path 2
1 is a three-way valve that communicates with the chamber 17e. Kagude, when the toner 14 is fed under pressure, the toner 14 is fed by the cylinder 17.
f is pushed and moves upward in the figure to close the second flow path 19, and when air is pumped, the valve body 17f is pushed by the air and moves downward in the figure to open the second flow path 9. .

In either case, this valve 17 directs Nq to the flow path 18.
is open. The valve 17 shown in FIG. 3(c) K houses a ball 174 in a chamber 17h formed in a housing 17g, and has a first flow path 18, a second flow path 19, and a third flow path.
The flow path 2I is a three-way valve that communicates with the chamber 17h. At this time, the convex portion 1 protrudes into the ball 17i chamber 17h.
In 7j, it is possible to prevent the fall due to its own l【(・ζ
In this state, the main air flows into the chamber 17h through the second flow path 19 through the y# 171 provided on the inner wall of the housing 17g.
When the toner 14 is being pumped, it moves upward in the figure and passes through the 27th passage I9 and the passage I9 1.c.
I] based on 4). fjlJ, ball 1
The width of the chamber 17h, the diameter of the ball 17i, and the opening diameter of the second flow path 19 are set appropriately so that the toner 7i is lighter than the toner 14 and prevents the toner 14 from going around to the second flow path 19 when the ball 17i rises. It is selected. Thus, toner 14
When the toner 14 is forced to feed, the ball 17i is pushed by the toner 14 and moves upward in the figure, blocking the second flow path 19. At the same time, when the air is being forced to be fed, that is, when the toner 14 is not being forced to be fed, the ball 17i is
i falls to the position of the convex portion +7j due to its own weight and opens the @2 channel 19.

In this square 17, in any case, the first flow path 18Ii
It's open.

In the embodiment of the present invention having such a valve 17, when the toner 14 is pumped by driving the pump 16, the valve 17 is
Since the second flow path 19 is closed by the V, the toner 14 does not go around to the second flow path 19 and is completely transferred to the third flow Il\32
It is sprayed onto the photosensitive surface 13a through the opening 12a in 1i ways. Incidentally, the toner 4 in the developing head shown in FIG.
If the toner 4 is pumped only by using the pressure-feeding system as shown in the above embodiment, the toner 4 will be transferred to the flow path 9, the intersection of the flow path 9 and the flow path 8, and the valve 7 and'. In the next squeeze step, this amount of toner 4 is mixed with air and sprayed onto the photosensitive surface 3a, causing stains on the photosensitive surface 3a or completely reducing the squeezing efficiency.On the other hand, In the squeeze step by driving the air pump 20 following the developing step in this embodiment, the valve 17 is
Channel L9'el:i! 4, the air flows into the third flow path 2.
1 and is sprayed onto the photosensitive surface 13a through the opening 12a. At this time, the valve 1 shown in FIG. 3(b) and FIG. 3(C)
7, since the first flow path 18 is also opened at the same time, some air enters the first flow path 18, but this does not have any adverse effect.

FIG. 4 shows another embodiment of the invention. A valve 17 is provided on the developing head side of the second flow path 19 through which air for full squeezing flows,
The toner 14f'i is directly supplied to the developing head through the first flow path 18. The valve 17 may be a one-way valve that allows flow only in the Rad direction from the second flow path 19 to the developer, and has advantages such as lower cost and simpler operation. Furthermore, when the pump 16 for feeding the developer is operated, the valve 17 is closed and air is accumulated in the piping 22, so the toner 14 does not reach the valve 17 and the squeeze air is wetted by the toner 14. Since there are fewer piping sections for flow, it is possible to further reduce defects such as staining of the photosensitive surface 13a during squeezing as described above.

In the embodiments shown in FIGS. 2 and 4, the air pump 20i is used as the means for pumping gas, but even if all compressed gas cylinders or liquefied gas cylinders are connected to the second flow path 19, the same operation and effect can be obtained. Ru. In addition to air, carbon dioxide gas, chlorofluorocarbon gas, propane gas, butane gas, etc. may be used as the gas for squeezing at this time. In addition, the photosensitive surface 13
Since the toner a is arranged vertically or nearly vertically as shown in FIGS. 2 and 4 VC, the liquid contained in the toner 14 falls under its own weight to the lower part of the photosensitive surface 13a.

Therefore, the squeezing gas may be sprayed toward the lower part.

As specifically explained above in conjunction with the embodiments, according to the present invention, the toner and squeeze gases are fully pumped, which not only simplifies the structure, but also provides a second flow channel that is exclusively used for gas conveyance. A valve can prevent toner from entering the tank.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the prior art, FIGS. 2 and 4 are sectional views showing an embodiment of the present invention, and FIGS. 3(a) to 3(C)
) is a sectional view showing the valve in detail. In the figure, 12a is an opening, 13 is a photosensitive material, 13a is a photosensitive surface, 14 is a toner, 16 is a pump, 17 is a valve, 18 is a first flow path, 19 is a second flow path, 20 is an air pump, 21 is a This is the third flow path. Patent Applicant: Fuji Photo Film Co., Ltd. Representative Patent Attorney: Shibu Mitsuishi (and 1 other person) Procedural amendment power 1968 z month λ / "ko", 1' Director-General of the Agency J ・11 A' 1 Indication 1982 Year patent application No. 2250475 Showa
Year number 11'' No. 2 Name of the invention Electrophotographic developing head 3, 711 city rent 1 (ill and B! Co., Ltd. 4 Agent Postal Code 107 Box 0 of the "Claims" in the specification 7. Details of the amendment M1 [4 yen - Scope of claims - I]
The amendment shall be made in accordance with the amended scope of patent claims. 8. Catalog of Attached Documents Amended Claims 1. Amended Claims (1) It has an opening facing the photosensitive surface of an electrophotographic photosensitive drum, and liquid toner is sprayed onto the photosensitive surface through this opening. U
At the same time, similarly, the toner is sprayed through the opening, and the toner is removed by spraying gas on the photosensitive surface afterward. In the developing head of the electrophotographic device, there is a means for force-feeding the toner, and a means for pumping the toner. An electrophotographic apparatus comprising a means for force feeding, a first channel through which toner exclusively passes, a second channel through which gas exclusively passes, and a valve that closes the second channel when toner is force fed. (2) The valve is provided at the intersection of the first flow path, the second flow path, and the third flow path that communicates with the opening and allows the toner and gas to mutually flow. Developing head for an electrophotographic apparatus according to item 1 iC. (3) Developing head for an electrophotographic apparatus according to claim 1, characterized in that the valve is provided in the second flow path =59 ) (

Claims (3)

[Claims] (1) An aperture facing the photosensitive surface of the electrophotographic photosensitive material is provided, and liquid toner is sprayed onto the photosensitive surface through this opening, and the toner is similarly sprayed onto the subsequent photosensitive surface through the opening. In a developing head of an electrophotographic apparatus in which toner is drained by fully applying gas, the means for fully pumping the toner, the means for fully pumping the gas, a first flow path through which toner exclusively passes, and a first flow path through which gas exclusively passes. A developing head for an electrophotographic apparatus, comprising: a second flow path; and a valve that completely closes the second flow path when toner is pumped and completely opens the second flow path when the gas is pumped. (2) The valve is provided at an intersection of a first flow path, a second flow path, and a third flow path that communicates with the opening and through which toner and gas alternately flow. A developing head for an electrophotographic apparatus as described in 1. (3) A developing head for an electrophotographic apparatus according to claim (1), wherein the valve is provided in the second flow path.