JP2001042650A - Liquid developing method and device for electrophotographic printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid developing method and a liquid developing device for an electrophotographic printed wiring board, by which an optimum fixing state is always obtained by preventing the fluctuation of the fixing state due to the thickness of a double-sided printed wiring board or the difference of the material of the board or the atmospheric temperature of a fixing part in the case of producing the board, and stable fixing processing is realized without causing transport jamming. SOLUTION: In this liquid developing method, fixing output of an arbitrary part position is dynamically controlled in matching with the fixing degree of toner particles by using a liquid developing device provided with a fixing output changing means 31, a fixing degree detection means 2 and a fixing output control means 33 in addition to a fixing means 16 in a fixing section 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board using an electrophotographic reversal developing method, and more particularly to a liquid developing method for performing a liquid toner developing process on an electrophotographic laminated board having an electrostatic latent image. The present invention relates to a liquid developing device.

[0002]

2. Description of the Related Art The preparation of a resist layer using an electrophotographic reversal development method is performed as follows. After providing a photoconductive layer on a copper-clad laminate and uniformly charging the surface of the photoconductive layer in the dark, by performing exposure in accordance with a wiring pattern, the charged portion of the exposed portion disappears and an electrostatic latent image is formed. . The electrostatic latent image is subjected to liquid toner development, drying, and fixing to form a toner image, and the toner image is used as a resist to dissolve and remove the photoconductive layer other than the toner image portion. A resist image of a metal conductive layer made of is formed.
Dissolution and removal of the unnecessary portion of the metal conductive layer and the subsequent steps of manufacturing the printed wiring board can be performed in the same manner as in the related art.

In this reversal developing method, the surface of the photoconductive layer is charged in the dark, and then, by exposing the image area, the charge in the exposed area is eliminated to form an electrostatic latent image. This is performed by adhering fine toner particles to an exposed portion, that is, a portion where the electric charge has disappeared. At this time,
A conductive member called a developing electrode is installed facing the electrostatic latent image surface, and by applying a bias voltage of the same polarity to this electrode, adhesion of toner particles to the exposed portion is promoted, and a high-quality toner is formed. An image is obtained.

A method of developing toner on both surfaces of a substrate using an electrophotographic method is disclosed in Japanese Patent Application Laid-Open No. Hei 6-224541. A metal conductive layer and a photoconductive layer are provided on both surfaces of an insulating substrate. It is possible to form a toner image on both sides by simultaneously developing both sides of the laminated plate.

Further, in accordance with application to an actual system, a liquid toner developing method by a one-side sequential developing method of obtaining toner images on both sides by repeating charging, exposure, and liquid toner development one by one has been put to practical use. JP-A-10-2096
No. 06, for example.

In the fixing process at the time of liquid development, toner particles are adhered to a portion corresponding to an electrostatic latent image through a liquid toner developing process and a drying process, and then the toner particles are melted by heat treatment to form a film. To obtain a toner resist image. The fixing unit is generally provided in a plurality of stages in the traveling direction, and when changing the degree of fixing, changing the transport speed during processing, changing the distance between the fixing unit and the substrate to be transported, or fixing. This was done by changing the amount of means used.

[0007] In the fixing process, if the amount of heat applied to the toner particles is insufficient, a fixing failure occurs, the function as a resist is deteriorated, and the toner that is not sufficiently melted when the alkali elution process is performed in the next step is performed. The photoconductive layer is also removed together with the particles, and eventually becomes a defect as a wiring pattern. In addition, fixing processing (excessive fixing) due to excessive heat
Is carried out, the film of the toner resist image is degraded, and if it is excessive, the photoconductive layer may be melted.

Therefore, in practice, substrates of various thicknesses and materials are processed, and therefore, under certain fixing conditions, when processing different substrates, poor fixing or over-fixing may occur due to the difference in heat capacity. Was.

Further, when the balance of the amount of heat during the fixing process on both sides of the substrate is different, the double-sided copper-clad laminate is a state in which copper foil is overlaid on both sides of the substrate such as glass epoxy.
The substrate itself may be warped due to the difference in the coefficient of thermal expansion between copper and resin, which may hinder the substrate transport in the fixing unit.

In the case where continuous processing of liquid toner development is performed, the ambient temperature of the fixing section of the liquid developing device rises due to continuous heating during the fixing processing, and as a result, over-fixing tends to occur as processing is repeated. That was the problem. Further, the above-described problem of transport failure due to the warpage of the substrate tends to occur remarkably when the ambient temperature rise speeds near both surfaces of the substrate during the continuous processing are different, and this is also one of the problems during the continuous processing. In addition, although the ambient temperature reaches a certain level due to the forced evacuation in the fixing unit, even if the optimum fixing condition is obtained in this state, a fixing defect may be caused in the initial rising stage of the continuous processing. .

[0011]

SUMMARY OF THE INVENTION According to the present invention, when a double-sided printed wiring board is manufactured by an electrophotographic reversal development method, a change in the fixing state due to a difference in the thickness of the substrate or the material of the substrate or the ambient temperature of the fixing section. To provide a liquid developing method and a liquid developing apparatus for an electrophotographic printed wiring board, which can always obtain an optimal fixing state while preventing the occurrence of a jam, and realize a stable fixing process without causing a conveyance jam or the like. Aim.

[0012]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have obtained an electrophotographic laminate obtained by forming a photoconductive layer on both sides of a double-sided copper-clad laminate. When manufacturing a printed wiring board by electrophotographic reversal development using the method, it is possible to continuously change the output of the fixing means when fixing the toner particles electrodeposited in the liquid toner developing section. As a result, it has been found that even when there is a difference depending on the thickness and the material of the electrophotographic laminate, it is possible to carry out the processing under optimum fixing conditions in accordance with the difference.

When the fixing output is changed, the fixing output is changed independently for any of the plurality of fixing means, so that the amount of heat on both sides of the electrophotographic laminate can be balanced. In addition, by detecting the degree of fixing at the time of the fixing process by the independent fixing unit and feeding it back to the fixing unit to dynamically and independently control the fixing output, during the continuous processing of the substrate, In this case, stable conveyance is always realized, and an optimal fixing state can be maintained.

The production of a printed wiring board by the above-mentioned method is performed by forming an electrophotographic laminate obtained by forming a photoconductive layer on both sides of a double-sided copper-clad laminate by electrophotographic reversal development. In a liquid developing device to be manufactured, the present invention is achieved by a liquid developing device for an electrophotographic printed wiring board having a fixing / fixing output changing unit, a fixing degree detecting unit, and a fixing output control unit.

Therefore, the liquid developing method of the present invention is achieved by using the above liquid developing apparatus for an electrophotographic laminate having an electrostatic latent image formed on at least one side by an appropriate charging and exposure process. In particular, with respect to the fixing process, it is possible to prevent a change in the fixing state due to a difference in the thickness of the substrate or the material of the substrate and an ambient temperature of the fixing section, to always obtain an optimum fixing state, and to cause a conveyance jam or the like. This is a method for realizing a stable fixing process without any problem.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A liquid developing method and a liquid developing apparatus for a printed wiring board according to the present invention will be described in detail below. The liquid developing apparatus for a printed wiring board according to the present invention basically includes a printed wiring board according to the present invention. A board liquid developing method can be applied, and the printed wiring board liquid developing method of the present invention can be made superior by using the printed wiring board liquid developing apparatus of the present invention. Therefore, hereinafter, the printed wiring board liquid developing method of the present invention will be described while describing the printed wiring board liquid developing apparatus of the present invention.

The liquid developing apparatus for a printed wiring board of the present invention is an apparatus for performing a liquid toner developing process when a printed wiring board is manufactured by utilizing an electrophotographic reversal developing method. In the process of manufacturing a printed wiring board having a circuit on both sides from a developing object having at least a photoconductive layer on both sides of the board, it is responsible for forming a toner image corresponding to a wiring pattern.

Specifically, as a liquid developing apparatus of the present invention, an apparatus of the following system can be used as a basic configuration. Japanese Patent Application Laid-Open No. 2-91649 discloses a conventional horizontal / horizontal developing method in which a conventionally used electrostatic latent image forming surface is conveyed substantially horizontally in the vertical direction and liquid toner is supplied to one surface from the upper or lower surface. A vertical substrate is transported substantially vertically, and toner is supplied to one side of the substrate. One-sided vertical and horizontal development, and a substrate as described in JP-A-6-224541 is laid down and transported substantially horizontally. -Side horizontal and horizontal development that supplies toner to both sides of a substrate from Japanese Patent Application No. 8-2983
As described in No. 63, there is a method such as double-sided vertical and horizontal development in which a substrate is set up and conveyed substantially vertically, and toner is supplied to both sides thereof. The liquid development method by the photo reversal development method is followed.

FIG. 1 is a sectional view showing the structure of an embodiment of the liquid developing apparatus for a printed wiring board according to the present invention. In FIG. 1, the liquid developing device basically has the same configuration as the above-described two-sided horizontal and horizontal developing system, and includes a liquid toner developing unit 2, a drying unit 3, and a fixing unit 4. The liquid toner developing unit 2 includes an upper developing electrode 11, a lower developing electrode 12, a feed roll pair 13, and a squeeze roll pair 14, which supply a liquid toner and simultaneously apply a bias voltage. A toner image is formed on the electrostatic latent image obtained by the exposure process. In addition, the drying unit 3 performs evaporation and removal of the dispersion medium in the liquid toner remaining on the surface by the blowing unit 15 to dry the liquid toner. The fixing unit 4 includes a fixing unit 16,
Fixing / fixing output changing means 31 and fixing degree detecting means 3
2. The fixing output control means 33, which basically melts and fixes the toner particles by uniformly heating the substrate surface, and finally obtains a resist corresponding to the wiring pattern on the electrophotographic laminate. .

In the process for producing a printed wiring board according to the present invention, first, one side or both sides of an electrophotographic laminate obtained by forming a photoconductive layer on both sides of a double-sided copper-clad laminate are subjected to charging and exposure treatments, After forming an electrostatic latent image corresponding to the wiring pattern, the liquid developing device performs a liquid toner developing process and a drying process, and then the fixing unit 16, the fixing output changing unit 31, and the fixing degree detection In the fixing section 4 including the fixing means 32 and the fixing output control means 33, the fixing output changing means 31 sets initial fixing output conditions in accordance with the thickness and material of the substrate to be processed, so that the fixing failure can be prevented.
Alternatively, it is possible to obtain a toner resist image free from defects due to overfixing. Further, during continuous processing, the fixing degree is constantly monitored by the fixing degree detecting means 32, and the output of the fixing means 16 is dynamically adjusted while feeding back the fixing degree to the fixing output changing means 31 through the fixing output control means 33. By always uniformly heating the substrate surface under the optimal fixing conditions, it is possible to always appropriately fuse and fix the toner particles.

Further, with respect to a plurality of fixing units 16 (at least two at positions opposed to both surfaces of the developing object), separate fixing output changing units 31, fixing degree detecting units 32, and fixing output control units are independently provided. The fixing means 16 is connected to the fixing means 33 so that the fixing output of each fixing means 16 can be controlled independently. As a result, it is possible to control the balance of the amount of heat during the fixing process on both surfaces of the substrate, without causing warpage of the substrate itself due to the difference in the coefficient of thermal expansion between the copper and the resin of the substrate, and providing a favorable fixing portion. Substrate conveyance can be realized.

As the fixing means according to the present invention, it suffices that the toner particles are melted by applying a predetermined amount or more of heat per fixed time to the toner particles on the substrate.
Specifically, a halogen lamp, a hot air dryer, an infrared panel heater, and the like can be given.

The fixing degree detecting means according to the present invention only needs to be capable of directly or indirectly detecting the fixing state of the toner particles, and specifically, the substrate surface temperature, the toner reflection density, and the fixing state. Although there is a detecting means for detecting the ambient temperature of the section, the present invention is not limited to this. When controlling a plurality of fixing units independently, the fixing degree detecting unit is basically preferably installed independently at a position corresponding to each fixing unit. It is also possible to control the fixing output by correlating the control settings of the respective fixing means with the means.

[0024]

Embodiments of the present invention will be described below in more detail with reference to FIG. 1. However, the present invention is not limited to the following embodiments without departing from the gist thereof.

Next, the liquid developing apparatus for an electrophotographic printed wiring board used in the present embodiment shown in FIG. 1 will be described in detail. The present liquid developing apparatus performs edge support conveyance, and has a different thickness of 51%.
It is possible to perform continuous liquid development simultaneously on both sides of an electrophotographic laminate (development object) having a width of 0 mm without contact. In the liquid toner developing unit 2, an upper developing electrode 11 that supplies a liquid toner and simultaneously applies a bias voltage, a lower developing electrode 12,
It comprises a feed roll pair 13 and a squeeze roll pair 14, and forms a toner image on both sides simultaneously on the electrostatic latent image obtained by the charging and exposure steps in the previous step. Further, the drying section 3 performs evaporation and removal of the dispersion medium in the liquid toner remaining on the surface by the blowing means 15 provided above and below, and performs drying of the liquid toner. Further, the fixing section 4 is provided with a total of four sets of fixing means 16 using seven halogen lamps, two sets of upper and lower, each of which is provided in two stages, and a fixing degree detecting means 32 for continuously setting the ambient temperature of the fixing section. By using a thermocouple so that it can be detected in an appropriate manner, by installing the thermocouples one by one on the top and bottom,
It is possible to independently detect the ambient temperature of the upper surface and the lower surface of the substrate. Further, general-purpose power controllers and temperature controllers are used as the fixing output changing means 31 and the fixing output control means 33, respectively. These enable independent control of the fixing output on the upper and lower surfaces of the substrate. In the fixing section 4, forced exhaust is performed from the upper side of the apparatus.

Basically, a liquid developing process is performed using the above-described liquid developing apparatus, but a photoconductive layer is formed on the copper-clad laminate before the liquid developing process (production of an electrophotographic laminate), and Formation of an electrostatic latent image on the obtained electrophotographic laminate was performed as follows.

Preparation of Electrophotographic Laminate (Developed Object) A rectangular double-sided copper-clad laminate (CCL-E170, manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a through hole of 340 mm × 512 mm and a copper thickness of 18 μm. An electrophotographic laminate having a 5 μm-thick photoconductive layer formed on both sides by a roll coating method was prepared. At this time, the copper-clad laminate is subjected to a roll coating process with a width of 512 mm, and the roll width used for the roll coating is set to 492 mm, so that both sides of the short side of the electrophotographic laminate have a width of 10 mm from the end. No photoconductive layer was formed, and a margin for grounding was secured.

Formation of Electrostatic Latent Image In the dark, both sides of the electrophotographic laminate are charged substantially uniformly to +250 V using a corona charger, and then exposed to light by a general contact exposure apparatus. To form an electrostatic latent image corresponding to the resist image. Thus, it was possible to perform one continuous exposure process per minute.

Example 1 First, after a developing object having been subjected to an exposure process with a thickness of 0.2 mm was placed at the entrance, conveyance was started at 1.0 m / min. Thereafter, in the liquid toner developing section 2, in order from the transport direction, the toner developing solution (positive charge toner: manufactured by Mitsubishi Paper Mills, Inc., “E”) is supplied from both the upper developing electrode 11 and the lower developing electrode 12.
LOPC-TW ") and +
By applying a bias voltage of 120 V, the electrodeposition of the toner on the development surface by the electrophotographic reversal development method was completed. Further, in the drying unit 3, the toner developing solution was dried by removing the dispersion medium in the toner developing solution remaining on the surface by evaporation.

Further, in the fixing section 4, the fixing output was not controlled by the fixing output control means 33, and the fixing output was set to 60% in both the upper and lower directions by the fixing output changing means 31 to perform the fixing. As a result, the toner particles of the first sheet in the liquid development process are completely fixed with respect to the development target having a thickness of 0.2 mm, and after the alkali elution process and the copper etching process in the subsequent steps, there is no defect due to disconnection. A printed wiring pattern was obtained.

Example 2 One electrophotographic laminate having a thickness of 0.6 mm was prepared in the same manner as in Example 1, and subjected to charging, exposure, double-sided liquid development, and drying.
After that, the fixing output control was turned off, and the fixing output was 85% for both upper and lower sides.
The fixing process was performed under the following settings.

As a result, the liquid developing process can be performed with respect to the developing object having a thickness of 0.6 mm without changing the conveying speed during the liquid developing process (fixing) or changing the distance of the fixing unit from the surface of the developing object. The first sheet of toner particles was completely fixed, and a favorable printed wiring pattern free from defects due to disconnection was obtained through alkali elution treatment and copper etching treatment in the subsequent steps.

In Examples 1 and 2, with respect to the first sheet of the liquid development processing, the warpage of the substrate due to the difference in the amount of fixing heat between the front and back surfaces of the developing object did not cause a conveyance failure.

Example 3 Fifty 0.2 mm-thick electrophotographic laminates were prepared, and one
The double-sided liquid toner developing process was performed continuously for 50 sheets at a takt time of 50 minutes. At this time, the fixing output control was turned on (upper limit of 100 degrees for both upper and lower ambient temperatures, P control), and the upper surface fixing output 6
The fixing process was performed at a setting of 0% and a lower surface fixing output of 50% (initial).

Fixing of toner particles For all substrates, melting and fixing of toner particles are performed without any problem. Also, no transport failure due to substrate warpage caused by a difference in upper and lower fixing heat amounts occurs, and alkali elution treatment in a subsequent process is performed. By the copper etching process, good printed wiring patterns free from defects due to disconnection were obtained on all 50 sheets. On this occasion,
The ambient temperature rose to a maximum of 83 degrees above and 95 degrees below.

COMPARATIVE EXAMPLE 1 In the same manner as in Example 3, 50 electrophotographic laminates having a thickness of 0.2 mm were prepared, and a double-sided liquid toner developing process was continuously performed on 50 sheets at a takt time of 1 sheet / min. . At that time, the fixing output control was turned off, the upper surface fixing output was 60%, and the lower surface fixing output was 5%.
The fixing process was performed at a setting of 0% (initial).

Fixing of toner particles The melting and fixing of the toner particles were carried out on all the substrates without any problem. However, from the sixth sheet onward, the warpage of the substrates due to the difference between the upper and lower ambient temperatures increased, and some defects were found in the wiring pattern. Admitted. In addition, 13
For the first and subsequent sheets, crack defects were observed in the melted toner film, and the pattern was lost due to the alkali elution treatment and copper etching treatment in the subsequent steps, causing disconnection defects. This is due to overfixing. At this time, the ambient temperature rose to a maximum of 113 degrees on the upper side and 130 degrees on the lower side.

[0038]

As described above, according to the liquid developing method using the liquid developing apparatus of the present invention, when a double-sided printed wiring board is manufactured by the electrophotographic reversal developing method, the thickness of the substrate is reduced.
Alternatively, it is possible to prevent the fluctuation of the fixing state due to the difference in the substrate material and the ambient temperature of the fixing section, to always obtain the optimum fixing state, and to realize a stable fixing process without causing a conveyance jam or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of a liquid developing device for a printed wiring board according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic laminate on which electrostatic latent image is formed 2 liquid toner developing section 3 drying section 4 fixing section 11 upper developing electrode 12 lower developing electrode 13 feed roll pair 14 squeeze roll pair 15 blowing means 16 fixing means 21 liquid developed toner 22 Toner Pipe 23 Toner Pump 31 Fixing Output Changing Means 32 Fixing Degree Detection Means 33 Fixing Output Control Means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsutaka Inoue 3-4-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2H074 AA44 BB02 BB14 BB32 BB44 BB54 CC01 EE09

Claims (4)

[Claims] When a printed wiring board is manufactured by an electrophotographic reversal development method using an electrophotographic laminate obtained by forming a photoconductive layer on both sides of a double-sided copper-clad laminate, electrodeposition is performed in a liquid toner developing section. A method for developing a liquid for an electrophotographic printed wiring board, comprising: changing the output of a fixing unit when fixing the toner particles obtained. 2. When the fixing output is changed as described above,
Regarding any one of the plurality of fixing means,
2. The liquid developing method for an electrophotographic printed wiring board according to claim 1, wherein the fixing output is changed independently. 3. The electrophotographic print according to claim 1, wherein the fixing output is dynamically and independently controlled by detecting a fixing degree at the time of fixing of the toner particles and feeding back to the fixing means. Liquid development method for wiring boards. 4. A liquid toner developing apparatus for manufacturing a printed wiring board by an electrophotographic reversal development method using an electrophotographic laminate obtained by forming a photoconductive layer on both sides of a double-sided copper-clad laminate. A liquid developing apparatus for an electrophotographic printed wiring board, comprising: a fixing output changing unit; a fixing degree detecting unit; and a fixing output control unit.