JPH10142949A - Liquid developing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a uniform and excellent image on both surfaces of a body to be developed provided with a photoconductive layer on both surfaces of a supporting body by forming an electrostatic latent image on the surface of the body to be developed provided with the photoconductive layer on both surfaces of the supporting body by an electrophotographic method and developing it by liquid by almost vertically holding the body to be developed while liquid developer is supplied from both sides. SOLUTION: This device is constituted of a liquid developing part 1, a drying part and a thermal fixing part. The body to be developed 5 provided with the photoconductive layer on both surf aces of the supporting body and obtained by forming a latent image on both photoconductive layer-surfaces is carried in the developing electrode part 3 of the liquid developing device by a carrying roll pair 21 and developed by the liquid at the electrode part 3. Thereafter, it is carried out to the drying part and the thermal fixing part by a liquid squeezing roll pair 22. After the body to be developed 5 is developed by the liquid at the developing part 1, the evaporation of media scattered in the liquid developer left on both photoconductive layer- surfaces is eliminated at the drying part and toner grains are thermally fixed on the photoconductive layer at the thermal fixing part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid developing method and a liquid developing apparatus for developing a developing object having a photoconductive layer on both sides of a support on both sides, and more particularly, to a developing method having a minute concave portion on the surface of the developing object. The present invention relates to a liquid developing method and a liquid developing apparatus suitable for developing a developing object having a through-hole such as a printed wiring board having a through-hole.

[0002]

2. Description of the Related Art In an image forming method by electrophotography using a liquid developer, a predetermined charging step is performed on a photoconductive layer in a dark place, and a uniform charge is applied. Next, an electrostatic latent image corresponding to the image is formed by exposure. Subsequently, after a toner image corresponding to the electrostatic latent image is formed using a liquid developer in a toner developing section, excess liquid developer is removed. Depending on the purpose of image formation, the obtained toner image is transferred to another image forming body, or the liquid developer dispersion medium is dried and the toner is thermally fused while being held on the photoconductive layer, and the toner image is fixed. Is done.

At present, the photosensitive region of the photoconductive layer used in these devices has reached the infrared region, and with the development of computer image processing technology, large-capacity data memory development and data communication technology, etc., original input, correction, editing, An electronic editing system has been put into practical use that can be operated from a computer consistently from layout to page layout, and can be immediately output to a remote terminal plotter through a high-speed communication network or satellite communication. Light source (semiconductor laser, H
A direct exposure system from a computer using an e-Ne laser or the like without using a silver halide film has been put to practical use.

On the other hand, in the production of printed wiring boards, as electronic devices have become lighter, thinner, smaller and more diversified, printed wiring boards are also required to have higher densities and shorter construction periods. Applications of the electrophotographic photosensitive member are being studied. The method for producing a resist layer using electrophotography is as follows. A conductive substrate provided with a metal conductive layer on an insulating substrate is provided with a photoconductive layer on the metal conductive layer, and the surface of the photoconductive layer is uniformly charged in the dark. Thereafter, an electrostatic latent image corresponding to the circuit image is formed by exposure. The electrostatic latent image is developed with a liquid developer, and a fixing process is performed to form a toner image. The photoconductive layer in the portion where the toner image is not formed is dissolved and removed, and a resist image of the metal conductive layer composed of the toner image and the photoconductive layer is prepared.

At present, in order to cope with the high density of printed wiring boards, not only are printed circuits provided on both sides of a substrate, but also printed circuits having a multilayer structure and each substrate connected by a hole called a through hole. 2. Description of the Related Art Production of wiring boards has been performed. A method in which a resist layer is formed on both surfaces of a base material using electrophotography is also disclosed in Japanese Patent Application Laid-Open No. 6-224541, and a laminate in which a metal conductive layer and a photoconductive layer are provided on both surfaces of an insulating substrate. The plate can be developed on both sides simultaneously to form toner images on both sides.

Conventional developing devices including such a double-sided liquid developing device generally have a horizontal developing section as shown in FIG. 4, and the surface of the object on which an electrostatic latent image is provided is horizontal. And the liquid development process is performed. In order to obtain a toner image having high resolution, it is necessary to remove excess liquid developer after toner image formation as quickly and uniformly as possible. In general, as a method for removing the excess liquid developer, various methods such as a squeeze roll method in which the object to be developed is sandwiched between upper and lower roll pairs, an air knife method in which gas is blown onto the surface of the object to be developed, and a squeeze method in which corona charging is used are disclosed. Have been. Among them, the squeeze roll method is predominantly used as the squeeze means in view of simplicity, squeezing effect, uniformity in the squeezing width direction, and the like.

[0007] However, in the developing process of a developing object having a shape in which an image forming surface of the developing object is not smooth and surplus liquid developer remains as a result, or a printed wiring board having through holes, the latter method is used. 5, the surplus liquid developer 8 accumulated in the through-hole 6 is removed from the through-hole 6 even after passing through the squeeze roll pair 22 when the squeeze roll pair 22 is used as the squeezing means. Will remain inside. This phenomenon becomes more conspicuous as the diameter of the through hole 6 becomes smaller. However, in any case, the remaining liquid developer 8 may go under the substrate from inside the through hole 6 to disturb the toner image on the lower surface. . Further, the liquid developer 8 remaining in the through hole 6 adheres to the squeeze roll pair 22 and solidifies,
This causes re-adhesion to the developing object, and also causes a problem that the uniform squeeze effect of the squeeze roll pair 22 is reduced.

In order to solve these problems, Japanese Patent Laid-Open Publication No.
Japanese Patent Application Laid-Open No. 603-603 discloses a liquid developing device in which at least one of a squeeze roll pair is a liquid absorbing roll having a capillary action, and a liquid developing device that processes a developing target using a liquid developer in a developing unit. At least one pair of squeeze rolls is provided on the downstream side of the developing unit, at least one of the squeeze rolls is a suction roll having a capillary action, and a liquid developing device provided with a reduced-pressure suction means connected to the suction roll. An apparatus is disclosed.

However, even when the above-mentioned liquid absorbing roll is used and the pressure reducing suction means is additionally provided, if the transport speed of the developing object is increased, the excess liquid developer in the through-hole is not enough. The liquid developer may remain because the developing object passes through the liquid absorbing roll before the liquid is absorbed by the developer. In order to prevent this, if a plurality of sets of liquid absorbing means including a liquid absorbing roll are provided or the degree of decompression of the decompression and suction means is increased, not only the size of the liquid developing apparatus itself but also the original image area should be increased. There is a high possibility that the toner before fixing is also removed. Further, when the thickness of the substrate is increased, the amount of the excess liquid developer inside the through-hole is increased, so that the substrate sometimes remains inside the through-hole.

Further, in order to form a uniform and good image on both surfaces of the object to be developed, the liquid developer must be supplied from the liquid developer supply means to both surfaces of the object under the same conditions. When the developing electrode is provided substantially horizontally,
Even if some liquid developer holding means is provided on the lower surface side of the developing object, the supply amount and the supply pressure of the liquid developer to the developing object are different on the upper and lower surfaces, and as a result, the toner image on both surfaces of the developing object is And the like, it was difficult to form a uniform and good image on both sides.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid developing method and a liquid developing apparatus for developing both sides of a developing object having a photoconductive layer on both sides of a support. The size of the liquid developing device can be increased even if the surface of the developing object has minute concave portions or the developing object has a through-hole such as a through hole and an excess liquid developer may remain. It is an object of the present invention to provide a liquid developing method and a liquid developing apparatus which can form a uniform and good image with no necessity and stains on both surfaces.

[0012]

As a result of intensive studies to solve the above problems, an electrostatic latent image is provided by electrophotography on both sides of a developing object having a photoconductive layer on both sides of a support, and from both sides. It has been found that it is sufficient to carry out liquid development processing while the liquid developer is supplied and the developing object is held substantially vertically.

[0013] In the liquid developing process for holding the object to be developed substantially vertically, in a liquid developing apparatus for performing a developing process by supplying a liquid developer while transporting the object to be developed between opposing developing electrodes, Both of the opposed developing electrodes may have liquid developer supply means, and the developing electrodes may be installed substantially vertically.

Accordingly, the supply amount and the supply pressure of the liquid developer supplied from the liquid developer supply means to the developing object can be made the same on both surfaces of the developing object without providing the liquid developer holding means. In addition, uniform and good images can be formed on both surfaces.

In addition, a through hole is formed in the laminate, in which the first metal conductive layer is provided on both sides of the insulating substrate, and a metal plating process is performed on the laminate to form a second hole in the through hole and on the surface of the laminate. A photoconductive layer is formed on the second metal conductive layer after the metal conductive layer is provided, and a surplus liquid developer remains inside the through-hole after passing through the squeezing liquid roll pair. However, since the excess liquid developer is retained inside the through hole as shown in FIG. 3, it is suitable because it does not flow out to the surface of the photoconductive layer and does not disturb the toner image.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The liquid developing method and the liquid developing apparatus of the present invention will be described in detail below. The liquid developing apparatus of the present invention basically employs the liquid developing method of the present invention. Further, the liquid developing method of the present invention is advantageously achieved by using the liquid developing apparatus of the present invention. Therefore, the liquid developing method of the present invention will be described below while describing the liquid developing apparatus of the present invention.

According to the liquid developing method of the present invention, a through-hole is formed in a developing object having a photoconductive layer on both sides of a support, for example, a laminated plate having a first metal conductive layer provided on both sides of an insulating substrate. After a plating process is performed to provide a second metal conductive layer inside the through-hole and on the surface of the laminated plate, a photoconductive layer is formed on the second metal conductive layer. This is a liquid developing method in which an electrostatic latent image is provided, and a liquid developer is supplied from both sides while a developing target is held substantially vertically while liquid developing processing is performed. Further, in the object to be developed according to the present invention, both of the opposed developing electrodes have liquid developer supply means,
The development can be performed by a liquid developing device in which the developing electrode is installed substantially vertically.

Prior to the liquid developing process according to the present invention,
An electrostatic latent image is provided on both surfaces of a developing object having a photoconductive layer on both surfaces of the support by electrophotography. The electrostatic latent image forming method includes:
It comprises a charging step of the photoconductive layer and a drawing step by light irradiation. As the charging means in the charging step, conventionally, non-contact charging methods such as corotron method and scorotron method,
Contact charging methods such as conductive brush charging and conductive roll charging are known, and at least the photoconductive layer according to the present invention can be uniformly charged, and a potential of a certain degree or higher without deterioration or deformation of the photoconductive layer. Any method can be used as long as it can be secured. The corotron method is advantageously used in terms of charging efficiency and charging stability, but in this method, it is preferable to continuously charge, but it is preferable that each side be charged. A charging system is preferred.

The developing member having at least one surface of the photoconductive layer charged is exposed to an image by a known operation to form an electrostatic latent image. Examples of the exposure method include reflection image exposure using a xenon lamp, a tungsten lamp, a fluorescent lamp, or the like as a light source, contact exposure through a transparent positive film, and scanning exposure using a laser beam, a light emitting diode, or the like. The light source in the scanning exposure is He-Ne laser, argon ion laser, krypton ion laser, ruby laser, YAG laser, nitrogen laser, dye laser, excimer laser, GaAs / GaAlAs,
A laser light source such as a semiconductor laser such as InGaAsP can be used, or scanning exposure using a light emitting diode and a liquid crystal shutter (including a line printer type light source using a light emitting diode array, a liquid crystal shutter array, etc.) may be performed. .

In the present invention, an electrostatic latent image is provided on both surfaces of the object to be developed before the development processing of the present invention, but the photoconductive layer may be charged prior to image exposure (light irradiation). Even if charging and exposure are performed twice (both sides) one by one, both sides are charged one side at a time, one side or both sides are exposed simultaneously, and both sides are charged simultaneously, and one side or both sides are exposed simultaneously. Alternatively, after one surface is charged, the other surface may be charged at the same time as the surface is exposed, and the surface may be exposed last. If scanning exposure is performed, simultaneous double-sided exposure is not preferred. Further, the charging unit and the exposure unit may use the same unit on both sides, or may use different units.

In the present invention, a developer having a photoconductive layer on both sides of a support and an electrostatic latent image provided on both sides by electrophotography as described above is a liquid developer from both sides in the present invention. The liquid development process is performed while the developing object is held substantially vertically while supplying the liquid.
Hereinafter, the liquid developing process according to the liquid developing method of the present invention will be described based on the main part of the liquid developing device illustrated in FIG.

The liquid developing apparatus of the present invention comprises a liquid developing section 1 shown in FIG. 1, a drying section and a heat fixing section. Developed object 5 having photoconductive layers on both surfaces of a support, and having latent images formed on both surfaces of the photoconductive layers by charging and exposure treatment (not shown)
Is transported into the developing electrode unit 3 of the liquid developing device by the transport roll pair 21, subjected to liquid development processing in the developing electrode unit 3, and then to the drying unit and the heat fixing unit (not shown) by the squeeze roll pair 22. Is to be carried out. After the developing target 5 is liquid-developed in the liquid developing section 1, the drying medium is subjected to evaporation and removal of the dispersion medium in the liquid developer remaining on the surfaces of both photoconductive layers. Thus, the toner particles are thermally fixed on the photoconductive layer.

The liquid developing section 1 supplies a liquid developer 8 to the developing object 5 to substantially perform a liquid developing process on the developing object 5. , And a squeeze roll pair 22 for nipping and transporting the developing object 5 to the drying unit and squeezing the liquid developer remaining on the photoconductive layer. A liquid developer storage tank 29 for storing the liquid developer 8 is disposed below these, and the liquid developer 8 is supplied to the developing electrode via a liquid supply pipe 27 constituting liquid developer supply means. It is supplied to the section 3.

As shown in FIG. 2, the developing electrode section 3 is further provided substantially perpendicularly to each other with a predetermined gap therebetween. Liquid developer 8 stored in liquid storage tank 29
Is temporarily stored, rectified, made static, and the developing electrode 1 opposed thereto
Liquid developer supply means 12 and 14 for supplying the gaps 0 and 11 and a substantial transport path of the developing object 5 are formed, and the developing electrodes 10 and 11 and the electrostatic latent image forming surface of the developing object 5 are fixed to each other. Guides 24 and 25 having a concave structure for holding in a gap between
It is composed of Further, a bias voltage applying means (not shown) is connected to the developing electrodes 10 and 11 so that a bias voltage can be applied to the surface of the developing object 5 where an electrostatic latent image is formed.

A liquid developer supply port 40 is provided above the developing electrodes 10 and 11 and immediately below a junction with the upper transport guide 24. The liquid developer supply port 40 is desirably provided substantially over the entire length of the developing electrodes 10 and 11 in the transport direction (length direction) of the developing object, and is perpendicular to the length direction of the supply port (width direction). The opening diameter (width) may be any size that can supply an amount that can fill the gap between the developing electrodes 10 and 11. The specific width of the liquid developer supply port 40 is 1
10 to 10 mm is preferred, and 2 to 7 mm is preferred. The cross section of the liquid developer supply port 40 is a circle, an ellipse, an ellipse,
Any shape such as a polygon having more than a triangle, an irregular shape, or the like may be used. In the case of a shape having no continuity, it is preferable that a plurality of shapes are provided in a row in the transport direction.

In the vicinity of the joint between the developing electrodes 10 and 11 and the lower portions 13 and 15 of the liquid developer supply means, there are provided drainage holes 42 for the stored liquid developer. After the supply of the liquid developer 8 to the liquid developer supply means 12 and 14 is stopped, the stored liquid developer drain hole 42 is provided inside the liquid developer supply means 12 and 14 due to evaporation of the evaporation component in the liquid developer 8. The supply of the liquid developer 8 from the stored liquid developer drain hole 42 to the developing object 5 is not intended as a main component. Therefore, in order to enable ejection from the liquid developer supply port 40, at least the lowermost part of the liquid developer supply port 40 in the space formed by the developing electrodes 10 and 11 and the liquid developer supply means 12 and 14. The liquid developer 8 is filled.

The transfer guides 24 and 25 slide on the side surfaces of the developing object 5 in the recesses, and can transfer the developing electrodes 10 and 11 and the developing object 5 electrostatic latent image forming surface at a predetermined gap. The groove width has a margin of at least about 0.5 to 2 mm from the maximum thickness of the developing object 5.
Further, the width of the two convex portions is substantially equal to the width of the developing electrodes 10 and 11.
And a gap between the surface and the surface of the developing object 5 where the electrostatic latent image is to be formed.
Further, if the depth of the groove of the concave portion is too shallow, there is a risk that the developing object 5 may come off from the concave portion during conveyance and the gap between the developing object 5 and the electrostatic latent image forming surface may not be kept constant. 1
mm or more is preferable, and about 2 to 5 mm is preferable.

The transport guides 24 and 25 preferably have resistance to a liquid developer. In addition to metals such as iron, stainless steel and aluminum, resin guides such as polyethylene, polypropylene, polyvinyl chloride and Teflon are used. Can also be used. When a conductive material such as iron is used, it is necessary to prevent the developing electrodes 10 and 11 from being electrically connected to the developing object 5 through the transport guides 24 and 25.

The liquid developer supply means comprises a liquid supply pump (not shown), liquid amount adjusting valves 17 and 18, and a liquid supply pipe 27. The liquid developer 8 is supplied to the liquid developer storage tank 29 by the operation of the liquid supply pump. Is supplied to the liquid developer supply means 12 or 14 through the liquid amount adjustment valve 17 or 18. The supply amount of the liquid developer 8 to the developing object 5 is adjusted by the liquid amount adjusting valve 17 or 18 so that the discharge pressure from the liquid developer supply port 40 becomes the same on both surfaces of the developing object 5. .

The transport roll pair 21 is composed of at least a shaft and a roll made of an elastic material provided on the outer periphery thereof.
It is preferable that both the shaft and the elastic body have resistance to the liquid developer 8. Iron, stainless steel, aluminum or the like can be used for the shaft. Natural rubber, butyl rubber, urethane rubber, nitrile butyl rubber, or the like can be used for the elastic body. The transport roll pair 21 is supported by a pair of side plates 31 and 32 arranged along the transport direction of the developing object 5, and receives a driving force from a motor (not shown). A roll pressing mechanism (not shown) is disposed at both ends of the transport roll pair 21 so that the transport roll pair 21 is pressed by the pressure mechanism at least while the developing object 5 is being transported. Has become.

The squeeze roll pair 22 includes a pair of side plates 33 and 3
4 and is driven by a motor (not shown) to rotate at the same peripheral speed as the transport roll pair 21. Further, a roll pressing mechanism (not shown) is arranged at both ends of the squeeze roll pair 22, so that the squeeze roll pair 22 is pressed against at least while the developing object 5 is being conveyed.

The squeeze roll pair 22 has a structure described in Japanese Patent Application Laid-Open No. 8-766.
As described in Japanese Patent Publication No. 03-203, a member composed of a shaft and a liquid absorbing member having a capillary action can also be used. Iron, stainless steel, aluminum or the like can be used for the shaft.
As the liquid absorbing member, a sponge structure of an elastic body such as natural rubber, butyl rubber, urethane rubber, or nitrile butyl rubber, a woven fabric, a nonwoven fabric, and a resin impregnated material thereof can be used. The shaft and the liquid absorbing member are liquid developer 8
It is preferable that the material has resistance to. For example, a SUS304 shaft as a squeeze roll pair has a basis weight of 70 g / m2.
A non-woven fabric obtained by winding the non-woven fabric in ^{two or} more layers can be used.

The squeeze roll pair may be a squeeze roll composed of a squeeze member having a shaft and a capillary action, and may be provided with a reduced-pressure suction means connected to the squeeze roll.

A grounding mechanism (not shown) is arranged near the transport roll pair 21 and the squeeze roll pair 22 so as to be in contact with the copper foil or the copper plating layer on the side end portion or the side surface of the developing object 5. Is provided. Developing electrodes 10 and 1
A power source (not shown) is connected to the grounding mechanism 1 and the grounding mechanism. When an electrophotographic reversal developing method is performed, a bias voltage is applied to the developing object 5.

The bias voltage to be applied includes factors of the material system such as the type of the photoconductive layer, characteristics of the liquid developer (type, concentration, solvent, etc.), the surface potential of the charged portion and the non-charged portion of the electrostatic latent image,
It has an optimum range due to a plurality of factors such as factors such as a developing condition such as a distance between the developing electrode and the developing object and a transport speed of the developing object.

Next, the object to be developed according to the present invention will be described. Since the present invention is a liquid developing method and a liquid developing apparatus for developing a developing object substantially on both sides, the developing object according to the present invention can be developed on at least both sides with a liquid developer. Specifically, it has a photoconductive layer on at least both sides of the support.

In particular, according to the liquid developing method and the liquid developing apparatus of the present invention, a through-hole is formed in a laminated plate having a first metal conductive layer provided on both surfaces of an insulating substrate, and a metal plating process is performed to perform the inside of the through-hole. And a developing member having a photoconductive layer formed on the second metal conductive layer after the second metal conductive layer is provided on the surface of the laminate (hereinafter, this developing member is referred to as a developing member having a through hole). It is suitable for the development of

The support used for the object to be developed according to the present invention is such that at least a layer adjacent to the photoconductive layer according to the present invention has conductivity. Electrically conductive material, or a material in which a conductive layer is laminated on both surfaces of an insulating substrate.
Since the object to be developed according to the present invention has both sides of the support covered with the photoconductive layer, the ground for dissipating the charge of the photoconductive layer at the time of exposure is substantially connected to the end of the support. It will be. Therefore, it is desirable that the conductive layer has a thickness that can be substantially grounded. The specific thickness of the conductive layer is preferably 2 μm or more, more preferably 5 to 50 μm.
μm is good. The thickness of the entire support is 0.1 to
It is preferably 3 mm, more preferably 0.2 to 1.5 mm.

Examples of the support according to the present invention include thermoplastic resin sheets and thermosetting resin sheets such as polyester having a conductive layer made of metal or the like on both sides, impermeable and conductive paper, and the like. Or bimetals such as aluminum, zinc, copper-aluminum, copper-stainless, chromium-copper, chromium-copper-aluminum, chromium-lead-iron, chromium-copper-
Examples include a metal plate such as a trimetal such as stainless steel.

If the object to be developed having the above-mentioned support is finally used as a lithographic printing plate, the support preferably has at least the surface on which the photoconductive layer is to be subjected to a hydrophilic treatment. For lithographic printing plate applications, aluminum plates are preferably used. The aluminum plate may contain aluminum as a main component and contain a trace amount of a different element, and conventionally known and publicly available materials can be appropriately used.

The surface of the support may be subjected to graining treatment or anodic oxidation treatment by a known method for improving hydrophilicity and surface strength. The graining method includes a mechanical surface roughening method, an electrochemical surface roughening method, and a chemical surface selective dissolution method.
As the mechanical surface roughening method, methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method are known. The electrochemical surface roughening method is carried out in a hydrochloric acid or nitric acid electrolytic solution by using an alternating current or a direct current. The substrate thus roughened is used after being subjected to an alkali etching treatment and a neutralization treatment as necessary. On the other hand, the anodizing treatment is performed using sulfuric acid, phosphoric acid, oxalic acid or the like as an electrolyte, or a mixed acid thereof, and the amount of the anodized film is preferably 0.1 to 10 g / m ² , and more preferably 1 to 6 g. A range of / m ² is preferred.

Further, as a support relating to a developing object having a through-hole, a through-hole is formed in a laminated plate provided with a first metal conductive layer on both surfaces of an insulating substrate, and the through-hole is formed by performing a metal plating process. 2nd inside and on the laminate surface
Provided with the above-mentioned metal conductive layer.

The laminated board is a glass-based epoxy resin board, a paper-based phenolic board, a paper-based epoxy resin board,
Glass substrate polyimide resin plate, polyester film,
A first metal conductive layer made of copper, silver, aluminum, stainless steel, nichrome, tungsten, or the like is provided on both sides of a polyimide film, a polyamide film, a polyvinyl fluoride film, or the like. These laminated boards are described in "Printed Circuit Technology Handbook-Second Edition-"
Printed Circuit Society, published in 1993, published by Nikkan Kogyo Shimbun) can be used.

The thickness of the first metal conductive layer in the laminate is generally 5 μm to 35 μm, but a thicker or thinner one can be used. In order to provide high resolution, the thickness of the first metal conductive layer is preferably thin.

The support relating to the developing object having the through-hole is formed by forming a through-hole having a desired diameter in the above-mentioned laminated plate, and then performing a metal plating treatment to form a second plating on the inside of the through-hole and on the surface of the laminated plate. A metal conductive layer is formed. Copper is most often used for the second metal conductive layer, but when the metal used for the second metal conductive layer is copper, “Surface mounting technology” (June 1993, published by Nikkan Kogyo Shimbun) ) Described electroless copper plating-electrolytic copper plating process,
Lamination can be performed by a direct plating (direct electrolytic copper plating) process or the like.

A photoconductive layer is provided on the above-mentioned support. Casein, polyvinyl alcohol, hydroxyethylcellulose is provided between the support and the photoconductive layer, if necessary, in order to improve the adhesiveness and electrophotographic properties. Phenolic resins, styrene / maleic anhydride copolymers, maleic / acrylic acid copolymers, acrylic / methacrylic acid copolymers, polyacrylic acids, and alkali metal and / or ammonium salts of these polymer electrolytes, Ethanolamines and their hydrochlorides, oxalates, phosphates, citric acid,
And hydroxycarboxylic acids such as tartaric acid, and salts thereof, glycine, alanine, amino acids such as glutamic acid,
Aliphatic aminosulfonic acid such as sulfamic acid, (poly) aminopolyacetic acid such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, and triethylenetetraminehexaacetic acid, aminotri (methylenephosphonic) acid, 1-hydroxyethylidene-
(Poly) aminopoly (methylenephosphonic acid) such as 1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid) and the like, and at least a part of the acid groups of these compounds are composed of alkali metal salts or ammonium salts. An intermediate layer may be provided.

Further, fine particles such as titanium oxide, alumina, silica, zirconia, and antimony oxide may be used in combination in the intermediate layer. The thickness of the intermediate layer is not particularly limited, but may be at most about 10 μm irrespective of the support to be used, if the purpose is to provide adhesion of the photoconductive layer. Also,
When the electric conductivity of the intermediate layer is low, the electric charge of the photoconductive layer is hardly dissipated, and the photosensitivity is lowered to lower the resolution of the toner image. Therefore, the electric conductivity of the intermediate layer should be 10 ^-9 S / cm or more. preferable.

A photoconductive layer is provided on both sides of the above-mentioned support to obtain an object to be developed. The photoconductive layer according to the present invention contains at least a photoconductive compound and a binder resin. As the photoconductive compound, a known organic or inorganic photoconductive compound can be used. Examples of the organic photoconductive compound include metal-free or metal (oxide) phthalocyanine and naphthalocyanine, and derivatives thereof. Examples of the inorganic photoconductive compound include zinc oxide, titanium oxide, and cadmium sulfide. These photoconductive compounds may be used alone or in combination of two or more.

Specific examples of the binder resin used in the photoconductive layer according to the present invention include styrene / maleic acid monoester copolymer, methacrylic acid / methacrylic acid ester copolymer, styrene / methacrylic acid / methacrylic acid ester Such as copolymers, acrylic acid / methacrylic acid ester copolymers, styrene / acrylic acid / methacrylic acid ester copolymers, vinyl acetate / crotonic acid copolymers, and vinyl acetate / crotonic acid / methacrylic acid ester copolymers ,
Styrene, (meth) acrylate, vinyl acetate,
And copolymers of vinyl benzoate monomers and the like with (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid and the like, or carboxyl group-containing monomers such as maleic anhydride and fumaric acid monoesters, phenol Resins.

The mixing ratio of the photoconductive compound to the binder resin depends on the desired electrophotographic properties of the photoconductive layer, more specifically, the electrophotographic properties of the photoconductive compound used. In the minimum application amount of the binder resin obtained in (1), the mixing ratio of the minimum amount of the photoconductive compound capable of obtaining the desired photosensitivity is appropriate, and specifically, about 1 to 100% by weight of the binder resin. And more preferably about 5 to 40% by weight.

The object to be developed according to the present invention is obtained by applying and laminating a coating solution for forming a photoconductive layer on both sides of a support in a conventional manner. The coating liquid for forming a photoconductive layer is prepared by dissolving or dispersing components constituting the photoconductive layer in an appropriate solvent. The concentration of the effective components (such as the photoconductive compound and the binder resin) of the coating liquid and the solvent used for the coating liquid are appropriately selected depending on the coating method, drying conditions and the like. In particular, when producing a photoconductive layer by an electrodeposition method, at least water is used in combination as a solvent. Further, in order to make the binder resin water-soluble, the binder resin may be neutralized with a liquid containing a basic compound before use. As the basic compound, for example, an organic base such as triethylamine, diethylamine, and monoethanolamine, and an inorganic base such as sodium hydroxide, potassium hydroxide, and aqueous ammonia can be used.

When a component insoluble in a solvent, such as phthalocyanine, is used as the photoconductive compound, the average particle size is preferably 0.4 μm or less, more preferably 0.2 μm, using a disperser.
The following are used dispersedly. Further, if necessary, in addition to the photoconductive compound and the binder resin, the coating liquid, for the purpose of improving the film physical properties of the photoconductive layer, the viscosity of the coating liquid, and the dispersibility,
Plasticizers, surfactants and other additives can be added.

The lamination of the photoconductive layer according to the present invention on a support is performed by a dipping method, a bar coating method, a spray coating method, a roll coating method, a curtain coating method, an electrodeposition method, or the like. The photoconductive layer may be formed on one side and the other side by different methods, except when the photoconductive layer can be simultaneously laminated on both sides of the support as in the immersion method. In addition, the lamination of the photoconductive layer is performed by a method in which the components constituting the photoconductive layer are contained in the same layer, or a method in which the components constituting the photoconductive layer are separately contained in two or more layers. There is known a method of arranging a binder resin having strong adhesiveness, arranging a resin having a good charge in an upper layer, increasing the content of a photoconductive compound, and using a separated layer in different layers. Or the method of lamination. In the drying of the coating solution, it is preferable to set a mild drying condition because the electrophotographic characteristics may be deteriorated depending on the drying conditions (temperature and air volume) particularly in the initial drying zone.

When the photoconductive layer is thin, a required charging potential cannot be ensured, and a high-quality toner image cannot be obtained. Conversely, when the photoconductive layer is thick, the photoconductive layer other than the toner image portion in the subsequent process is eluted and removed. Not only promotes the deterioration of the eluate, but also deteriorates the thinning of the photoconductive layer due to the flow of the eluent from the layer direction of the photoconductive layer. Therefore, the thickness of the photoconductive layer according to the present invention is suitably about the minimum thickness at which a desired charging potential can be stably obtained in consideration of development. In the present invention, the thickness of the photoconductive layer is preferably 0.5 to 10 μm,
Further, the thickness is preferably 1 to 7 μm.

As the developing method in the liquid developing process according to the present invention, there are a reversal developing method in which an exposed portion is developed using toner particles having the same polarity as the electrostatic latent image, and a polarity opposite to the electrostatic latent image. Any of the normal development methods of developing non-exposed portions using toner particles having the following formulas can be used. In addition to the reversal development method, it is preferable to apply a bias voltage in the normal development method in order to prevent toner particles from adhering to non-image areas and pinholes in solid areas.

As the liquid developer used in the present invention, the liquid developer used for an electrophotographic printing plate can be used. However, the liquid developer has a resist property for elution and removal of a photoconductive layer of a circuit portion in a later step. Must be something. Therefore, as the toner particle particle component in the liquid developer, for example, methacrylic acid, acrylic resin composed of methacrylic acid ester, vinyl acetate resin, a copolymer of vinyl acetate and ethylene or vinyl chloride, vinyl chloride resin, Vinylidene chloride resin, vinyl acetal resin such as polyvinyl butyral, polystyrene, copolymer of styrene with butadiene or methacrylic acid ester, polyethylene, polypropylene and its chloride, polyester resin such as polyethylene terephthalate or polyethylene isophthalate, polycapramid or Polyamide resins such as polyhexamethylene adipamide, phenolic resins, xylene resins, alkyd resins, vinyl-modified alkyd resins, gelatin, cellulose ester derivatives such as carboxymethylcellulose, and the like. It is preferable to contain other wax, wax and the like.

The liquid developer may contain a dye or a charge control agent as long as the development or fixing is not adversely affected. Further, it is necessary to use either positive or negative charging depending on the photoconductive compound used and the charging polarity.

Lastly, the processing after the liquid development processing of the object to be developed according to the present invention will be described. The developing object according to the present invention including the developing object having through-holes provided with the toner development on both surfaces thereof is subsequently subjected to elution and removal of at least the non-image area photoconductive layer other than the toner image area with an alkaline processing liquid.

The treatment solution (eluate) used for elution includes
Liquid pH after preparation of eluate, containing at least alkaline agent
It is better to have a buffering capacity in the vicinity. Examples of the alkali agent to be contained include inorganic salts such as silicate, alkali metal hydroxide, alkali metal and ammonium salts of phosphoric acid and carbonic acid represented by the general formula SiO ₂ / M ₂ O (M represents an alkali metal atom). Alkaline agents, ethanolamines, ethylenediamine, propanediamines, triethylenetetramine, and organic alkali agents such as morpholine, and mixtures thereof can be used. Particularly, as the alkali agent, the above silicate is used for the photoconductive layer. It is advantageously used to show a suitable penetration rate and a strong buffering capacity.

The above-mentioned processing solution is further described in JP-A-55-25
No. 100, JP-A-56-14
No. 2528, a water-soluble amphoteric polymer electrolyte, a chelating agent described in JP-A-58-190952,
No. 177541, a liquid viscosity modifier described in
Components such as preservatives and bactericides described in JP-A-226657, various surfactants, and water-soluble polymers may be contained as necessary. The solvent used for the treatment liquid is not particularly limited as long as it can stably disperse and dissolve the above components, but soft water is advantageously used. Further, in order to more stably mix and disperse the above components, an organic solvent may be added to the treatment liquid together with the active ingredient of the treatment liquid within a range that does not substantially promote elution.

The developing object from which at least the non-image portion photoconductive layer has been eluted and removed is then rinsed on both sides to wash and remove the solubilized photoconductive layer components remaining on the support. The rinsing liquid used for rinsing is adjusted so that the binder resin used for the photoconductive layer according to the present invention does not re-aggregate. That is, if the initial pH of the rinsing liquid does not at least promote the insolubilization of the binder resin, the resin flowing together with the treatment liquid is kept in a solubilized state, and thus troubles due to re-insolubilization of the resin can be prevented. However, conversely, the pH of the rinse solution
If the pH is high, an elution effect is exhibited and image thinning is caused. Therefore, it is desirable to maintain the pH of the rinsing liquid at 10 or less.

When the object to be rinsed by the rinsing treatment is used as a lithographic printing plate, the protective gum treatment is performed for the purpose of improving the scratch resistance of the plate surface and desensitizing the non-image area. Is done. The protective gum solution that can be used in the present invention contains, in addition to hydrophilic polymer compounds such as gum arabic, organic and inorganic acids, acidic buffers, lipophilic substances, surfactants, and the like. All known ones can be used.

As the method and apparatus for eluting and removing the non-image area photoconductive layer of the developing object, conventionally known methods and apparatuses can be applied. In particular, the photosensitive layer and the image forming layer of the photoconductive layer are provided on both surfaces of the support. As a method and an apparatus for eluting and removing the image forming layer of the plate-like body having the above-mentioned features, see JP-A-2-52352 and JP-A-2-52352.
No. 52353, No. 2-52354, No. 2-52355
No. 2-52356, No. 2-93474, No. 2-
No. 132247, No. 2-275457, No. 2-275
Nos. 461, 3-29953 and 3-48849
Nos. 5,009,098 and 5,087,098, and these can also be used advantageously.

On the other hand, a developing object having a through hole is
Finally, since the photoconductive layer is advantageously used as a printed wiring board, the photoconductive layer other than the toner image portion is eluted and removed to form a resist image, and the metal conductive layer other than the resist image portion is etched away. The above-mentioned processing solution and apparatus can be used for elution and removal of the photoconductive layer, and the method described in the above-mentioned “Printed Circuit Technology Handbook-Second Edition” can be used for etching. The etchant may be any solution that can dissolve and remove the metal conductive layer and at least does not dissolve the photoconductive layer. In general, when a copper layer is used as the metal conductive layer, a ferric chloride solution, a cupric chloride solution, or the like can be used as an etching solution.

After the etching step, the circuit portion resist image
As with the manufacture of printed wiring boards using general resists such as resist inks, liquid resists, and dry film photoresists, by processing with a more alkaline solution than the processing liquid used for elution removal of the circuit part Can be removed. Also, if necessary,
Butanone, 1,4-dioxane, 1,2-dimethoxyethane, methanol, ethanol, 2-propanol, 1
Organic solvents that can dissolve the binder resin of the photoconductive layer, such as -methoxy-2-propanol, 2-methoxyethanol, and 2-butoxyethanol, can also be used.

[0066]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Embodiment 1 FIG. 1 is a schematic sectional view of an example of a liquid developing apparatus according to the present invention. After opening a through hole (0.5 mmφ) in a copper-clad laminate obtained by laminating copper foil on both sides of a 1.6 mm thick insulating substrate, copper plating is performed and copper plating is applied to the inside of the through hole and the surface of the copper foil. The developing member 5 having a photoconductive layer formed on the surface of the copper plating layer including the inside of the through hole 6 is formed with a latent image on both surfaces thereof by charging and exposure treatment (not shown). The pair is held by the pair 21 and transported to the developing electrode unit 3. The transport speed at this time is 10 m / m
in. As the transport roll pair 21, a roll formed by winding nitrile butyl rubber as an elastic body around a SUS304 shaft and having a finished hardness of 45 degrees was used.

As the squeeze roll pair 22, a non-woven fabric (BEMLISE CL, manufactured by Asahi Kasei Corporation) is attached to a stainless steel shaft.
EAN WIPE-P), and the diameter was the same as that of the transport roll pair 21.

The developing object 5 on which the electrostatic latent image has been formed by the charging and exposing steps is conveyed to the developing electrode unit 3 in the liquid developing apparatus of FIG. The developing object 5 is held substantially vertically by the conveying guides 24 and 25, and is conveyed without contacting the developing electrodes 10 and 11. The liquid developer 8 is adjusted in liquid amount by liquid amount adjusting valves 17 and 18 and is supplied with liquid developer supply means 12 and 14.
The liquid developer is supplied from the liquid developer supply port 40 so as to fill the gap formed by the developing electrodes 10 and 11. The liquid amount adjusting valves 17 and 18 are arranged such that the liquid amount of the liquid developer 8 from the respective liquid developer supply ports 40 is 3 liter / m.
It was adjusted to be in / cm ² . The bias voltage was set to 100V.

The surplus liquid developer 8 on both surfaces is squeezed by the squeeze roll pair 22 on the developed object 5 after the development. The surplus liquid developer 8 remained in the through-hole 6 after passing through the squeeze roll pair 22, but was not discharged to both surfaces of the substrate because it was located in the center of the through-hole. A uniform and clear toner image was obtained on the surface.

Example 2 As a member 5 to be developed, a through-hole (0.5 m) was formed in a copper-clad laminate in which copper foil was laminated on both sides of an insulating substrate having a thickness of 2.0 mm.
mφ), copper plating is performed to form a copper plating layer on the inside of the through hole and on the surface of the copper foil, and a photoconductive layer is provided on the copper plating layer including the inside of the through hole 6. The transport speed of the developing object 5 is 6 m /
The developing object was developed in the same manner as in Example 1 except that the min was set. The surplus liquid developer 8 remained in the through-hole 6 after passing through the squeeze roll pair 22, but was not discharged to both surfaces of the substrate because it was located in the center of the through-hole. A uniform and clear toner image was obtained on the surface.

Comparative Example A developing member was developed in the same manner as in Example 1, except that a conventional liquid developing device in which developing electrodes were horizontally arranged as shown in FIG. 4 was used as the liquid developing device. . The surplus liquid developer 8 remains in the through hole 6 of the developing object 5 after passing through the squeezing liquid roll pair 22, and is discharged to the lower surface of the substrate before entering the drying section and the fixing section in the next step, and The toner image is disturbed,
No clear toner image was obtained.

In the above embodiment, an example in which a printed wiring board having a through-hole, in which the effects of the present invention are advantageously exhibited, is developed, but the electrophotographic liquid developing apparatus of the present invention is a printed wiring board having no through-hole. It can also be used for developing a lithographic printing plate having a photoconductive layer provided on an aluminum or paper support.

[0074]

As described above, since the present invention has the above-described structure and operation, it is possible to develop a developing object having a through hole used for manufacturing a printed wiring board and having a photoconductive layer on both surfaces. The surplus liquid developer accumulated in the through hole does not stain the unfixed toner image on the developing object, and the liquid developer is supplied to both surfaces under the same conditions, so that a uniform and clear image can be obtained. Can be formed on both sides.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a liquid developing device of the present invention.

FIG. 2 is a schematic sectional view of a developing electrode and a liquid developer supply unit.

FIG. 3A is a schematic horizontal cross-sectional view near a squeeze roll pair using one example of the liquid developing device of the present invention. b: A schematic perspective cross-sectional view near a squeeze roll pair using an example of the liquid developing device of the present invention.

FIG. 4 is a schematic longitudinal sectional view of a conventional liquid developing device.

FIG. 5 is a schematic vertical cross-sectional view near a squeeze roll pair using a conventional liquid developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid developing part 3 Developing electrode part 5 Developed object 6 Through-hole 8 Liquid developer 10, 11 Developing electrode 12, 14 Liquid developer supply means 17, 18 Liquid amount control valve 21 Transport roll pair 22 Squeeze roll pair 24, 25 transport guide 27 liquid feed pipe 29 liquid developer storage tank 31, 32, 33, 34 side plate 40 liquid developer supply port

Claims (3)

[Claims] An electrostatic latent image is provided by electrophotography on both sides of a developing object having a photoconductive layer on both sides of a support, and the developing object is held substantially vertically while supplying a liquid developer from both sides. A liquid developing method comprising: 2. A through-hole is opened in a laminated plate having a first metal conductive layer provided on both surfaces of an insulating substrate, and a metal plating process is performed to provide a second metal conductive layer inside the through-hole and on the surface of the laminated plate. 2. The liquid developing method according to claim 1, wherein, after the developing, the developing object having the photoconductive layer formed on the second metal conductive layer is held substantially vertically to perform liquid developing processing. 3. A liquid developing apparatus for supplying a liquid developer while carrying a developing object between opposed developing electrodes and performing a developing process, wherein both of the opposed developing electrodes have a liquid developer supply means. A liquid developing device, wherein the developing electrode is installed substantially vertically.