JP2000183499A - Apparatus for exposing electrophotographic printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a uniformly charged state without depending upon performance of an exposure apparatus by providing a charger having a variable height and capable of scanning on a surface plate. SOLUTION: After an electrophotographic laminate 4 is mounted on a surface plate 3, a charger 5 applied by a voltage necessary for charging is scanned in a Y direction at a preset height and scanning speed to complete charging. Thereafter, exposure is finished, and a desired electrostatic latent image is obtained on the laminate 4. Accordingly, a charging step and an exposure step are separated, and since a charger scanning mechanism 6 and a moving mechanism of the plate 3 are separate, a scanning range of the charging condition is not narrowed according to the moving speed of the plate 3 of the apparatus, and the charging conditions of high degree of freedoms can be selected. When a thickness of the used laminate 4 is altered, a height of the charger 5 is changed to meet the thickness to obtain substantially similar charging state according to conventional charging conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printed wiring board exposure apparatus used for a charging and exposure process in a process of manufacturing a printed wiring board using electrophotography.

[0002]

2. Description of the Related Art As electronic devices become lighter, thinner, smaller and more diversified,
At present, high density and shortened construction period are also required for printed wiring boards.Instead of the conventional surface exposure drawing method using a photomask, direct drawing method using a flatbed scanning exposure apparatus is being studied. On the other hand, application of an electrophotographic photosensitive member as a resist material has been studied.

A method of forming a resist layer using electrophotography is to provide a photoconductive layer on a metal conductive layer of an insulating substrate in which a metal conductive layer is provided on an insulating substrate, and to uniformly form the surface of the photoconductive layer in the dark. Then, an electrostatic latent image corresponding to the wiring pattern is formed by exposure. The electrostatic latent image is subjected to toner development processing and fixing, and the toner image is used as a resist to dissolve and remove the photoconductive layer in the toner image non-formed portion, and a resist image of a metal conductive layer including the toner image and the photoconductive layer is formed. Is produced. 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.

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

In a printed wiring board, a photopolymer conventionally used and a resist material mentioned in a dry film include a photopolymer provided with a certain film thickness, or a dry film layer formed of ultraviolet light or the like. The exposed portion is cured or solubilized to form a resist layer. Therefore, since the charging step is not required for the resist material, it is not necessary to install at least a device capable of charging in the flatbed scanning exposure apparatus or in a step before that. When a resist material utilizing electrophotography is applied to a resist material that does not require such a charging step, the surface of the photoconductive layer is introduced before being introduced into the drawing apparatus as described above. Requires a step of charging.

[0006] As a flatbed scanning exposure apparatus which can be used when preparing a resist layer utilizing electrophotography, it is possible to use various lasers or those using light emitting diodes as light sources. The process is performed while moving at least one of the optical system and the object to be exposed. In addition, regardless of whether the optical system or the object to be moved during exposure, at least the surface plate on which the object to be exposed is mounted has a process of relatively moving to the exposure unit. An electrophotographic printed wiring board exposure apparatus has been developed which is capable of charging a photoconductive layer on the surface of an electrophotographic laminate within the exposure apparatus by being installed.

In the charging step including the above exposure apparatus, a corona charging method or a contact charging method is used. In general, an applied voltage of 5 to 10 kV is required for the corona charging method, and an applied voltage of about 0.5 to 2 kV may be used for a contact charging method using a roll-shaped charging body or a brush-shaped charging body. In the former case, there are not a few problems of safety maintenance and a problem of image defects due to discharge breakdown of the photoconductive layer due to the magnitude of the applied voltage. Even in the latter case, from the viewpoint of contacting the charged body, dust and dirt adhering to the charged body itself are liable to be affected, so that there is a problem that frequent cleaning of the charged body by a cleaner blade or the like is necessary. There are advantages and disadvantages. Generally, both charging methods are selected according to the applicable case.

Heretofore, regarding the exposure processing, a method of simultaneously performing exposure when the electrophotographic laminate is first moved to the exposure section while being charged, and the movement of the surface plate to the exposure section while being charged have been completed. Later, there were two methods of performing the exposure process separately from the charging process as the next step. In both cases, the charging device is fixed at a position just before the entrance of the exposure unit. In the former case, it is necessary to perform the charging process at the moving speed of the surface plate in accordance with the exposure processing, and therefore, the charging conditions are restricted. On the other hand, in the latter case, the charging step and the exposure step are separate, so that the charging conditions can be set flexibly. Therefore, the latter is preferable in terms of positioning of the exposure processing including the charging processing.
However, in some exposure devices, it is not possible to satisfy the operating conditions such as the moving speed and moving distance of the surface plate required as charging conditions due to space problems and problems in the specifications of the device. In some cases, it may be necessary to change the design of control or control, and it may be difficult to uniformly charge the entire surface of the electrophotographic laminate.

In the corona charging method, the amount of charge is adjusted by the distance between the electrode and the laminate, the applied voltage, and the transport speed of the laminate. In the conventional charging of the electrophotographic photosensitive member by the corona charging method, the thickness of the member to be charged is almost constant, so that the above conditions can be fixed.
Since the thickness of the electrophotographic laminate is as large as several tens of μm to several mm, the distance between the surface of the electrophotographic laminate and the charging device or other conditions must be set according to the electrophotographic laminate to be used. I needed to fix it.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a flatbed type electrophotographic printed wiring for charging and exposing an electrophotographic laminate having a metal conductive layer and a photoconductive layer provided on at least one surface of an insulating substrate by electrophotography. An object of the present invention is to provide an electrophotographic printed wiring board exposure apparatus capable of realizing a uniform charging state under a constant charging condition regardless of the performance of the exposure apparatus.

[0011]

In order to solve the above-mentioned problems, a flatbed scanning exposure apparatus for a printed wiring board includes at least a charging device, a power supply for the charging device, and a photoconductive layer in addition to a portion having an exposure function. A surface voltmeter for inspecting the charged potential of the surface is provided, and a grounding mechanism for ensuring grounding of the charged surface of the electrophotographic laminate is provided. A mechanism that scans at an arbitrary constant speed in the direction (hereinafter, charging device scanning mechanism) and a charging device height adjustment mechanism are provided.

Therefore, when the electrophotographic printed wiring board exposure apparatus of the present invention is used, a charging device to which a required voltage is applied is applied to the electrophotographic laminated board mounted on the surface plate separately from the exposure step. Since the scanning is performed by the driving mechanism, not only can charging be performed under any charging conditions, but the height of the charging device can be varied with respect to the thickness of the electrophotographic laminate, so that electrophotographic laminates having different thicknesses can be obtained. Also, when using, it is not necessary to change the charging condition drastically.

[0013] Further, a charging potential inspection system for an electrophotographic laminate by a surface voltmeter, a charging device scanning mechanism, a charging device height adjustment mechanism, and feedback control of at least one charging condition of a voltage applied to the charging device are performed by feedback control. In addition, it is possible to easily determine the optimal charging condition.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrophotographic printed wiring board exposure apparatus according to an embodiment of the present invention will be described in detail. FIG. 1 is a perspective view of an embodiment of an electrophotographic printed wiring board exposure apparatus according to the present invention. In FIG. 1, the electrophotographic printed wiring board exposure apparatus includes a charging device 5 and a charging device scanning mechanism including a driving device (not shown) for scanning the charging device in a sub-scanning direction (Y direction) of exposure. 6, a charging device height adjusting mechanism 7, and a surface electrometer measuring probe 8 for inspecting the charged potential of the photoconductive layer after charging. In addition, the charging device 5 is connected to a DC voltage applying unit (not shown) so that a constant voltage can be applied during charging. Further, by a grounding member (not shown),
At least while the photoconductive layer on the surface of the electrophotographic laminate 4 is charged, the grounding of the metal conductive layer portion of the electrophotographic laminate 4 is ensured.

As the charging device 5 according to the present invention, a general corona charging device, a roll charging device using a roll charging member, and a brush charging device using a brush charging member are applied.

In the electrophotographic printed wiring board exposure apparatus according to the present invention, after the electrophotographic laminate 4 is mounted on the surface plate 3, a voltage required for charging is applied at a preset height and scanning speed. The charging is completed by scanning the charged charging device 5 in the Y direction. Thereafter, the conventional exposure processing is completed, and a desired electrostatic latent image is obtained on the electrophotographic laminate 4.

Therefore, the charging step and the exposing step are separated, and the charging device scanning mechanism 6 and the moving mechanism of the surface plate are separate. Therefore, the operating range of the charging condition is narrowed by the moving speed of the surface plate of the exposure device. This makes it possible to select a charging condition having a high degree of freedom without being performed.

When the thickness of the electrophotographic laminate 4 to be used is changed, the same charging state can be obtained under the conventional charging conditions by changing the height of the charging device 5 in accordance with the change. Becomes If necessary, a system for measuring the distance between the surface of the electrophotographic laminate 4 and the charging device 5 using an optical sensor and automatically feeding back the measured result to the charging device height adjusting mechanism 7 may be added.

Further, the surface potential meter measurement probe 8 is provided at a position behind the charging device, and the surface potential can be measured immediately after charging is performed by scanning the charging device 5. I have. In this embodiment, the number of the surface potential measuring probes 8 is one, but the main scanning direction (X direction)
By providing a plurality of lines on the line, it is possible to confirm the uniformity of the surface potential in the main scanning direction. If the charging potential inspection system is added, the charging device scanning mechanism according to the present invention, and in combination with the function of the charging device height adjustment mechanism, the charging device scanning speed, the distance between the charging device and the surface of the electrophotographic laminate, If the feedback control is performed with respect to at least one charging condition of the voltage applied to the charging device, it is possible to easily determine the optimum charging condition.

[0020]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it departs from the gist. Further, details of a method and an apparatus for manufacturing a printed wiring board using electrophotography are described in JP-A-10-209606. Hereinafter, the charging and exposing steps, which are particularly regarded as a technical field to which the present invention belongs, will be described in detail.

Example 1 In this example, a red LED array type flatbed scanning exposure apparatus (Pulsar 9000 manufactured by Lavenir) (hereinafter, exposure apparatus) was applied as an exposure apparatus for an electrophotographic printed wiring board. In the exposure apparatus, the surface plate is 2
It moves at a speed of 0 m / min. In the exposure apparatus,
A corona charging device having a width of 520 mm was installed as a charging device. Further, the corona charger can scan on the surface plate in the sub-scanning direction (Y direction), and can adjust the distance between the wire of the corona charger and the surface of the surface plate. The scanning speed, the applied voltage, and the distance between the wire and the platen surface can be set to arbitrary values from 0 to 8.0 m / min, from 0 to 10 kV, and from 5 to 30 mm, respectively. In addition, a surface electrometer (GENTE)
C. E. S. V. METER_CATE 701), and the measurement probe of the surface voltmeter was attached to the corona charger so as to scan near the center of the surface plate in the main scanning direction (X direction).

First, a double-sided copper-clad laminate (340 × 510 × 0.8 mm, copper thickness 18 μm, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
An electrophotographic laminate having a 5 μm-thick photoconductive layer formed on both surfaces of m) by an immersion method was produced. Next, after placing and fixing the electrophotographic laminate on the surface plate of the exposure apparatus,
An electrostatic latent image was formed on the upper surface of the electrophotographic laminate through the charging and exposure steps in the dark. At this time, the scanning speed of the charging device,
The applied voltage and the height of the wire were 5.5 m /
min, 6.0 kV, and 15 mm,
A charging potential of 270 V was obtained on the surface of the photoconductive layer of the electrophotographic laminate.

Thereafter, a good resist image was obtained by a conventional liquid toner developing process. Furthermore, a desired resist image could be formed on both surfaces by treating the surface on which no resist image was obtained by the same process. Furthermore, removal of the non-resist part photoconductive layer, Cu etching treatment, and resist peeling treatment were performed to obtain a desired printed wiring board. No problems were found in the obtained copper wiring pattern, such as missing wiring, increased line width, and contamination of the non-image area.

Example 2 Using the same exposure apparatus as in Example 1, a thickness of 0.1 mm
Double-sided copper-clad laminate (Mitsubishi Gas Chemical Co., Ltd., 340 × 5
(10 × 0.1 mm, copper thickness: 18 μm) was attempted to produce a double-sided printed wiring board. The processing steps after the formation of the photoconductive layer and the development of the liquid toner were performed in the same manner as in Example 1.

Embodiment 1 concerning the charging device of the exposure apparatus
The charging conditions were the same as those described above, that is, the scanning speed of the charging device, the applied voltage, and the height of the wire were each 5.5 m / m.
in, 6.0 kV, 15 mm, and charged to 240 V on the surface of the photoconductive layer of the electrophotographic laminate.
Was obtained.

Further, regarding the charging conditions, when only the scanning speed of the charging device was reduced from 5.5 to 5.2 m / min, a surface potential of 270 V could be obtained. Also, when the height of the wire was changed to 14.3 mm,
Similarly, a surface potential of 270 V was obtained. Therefore, it is possible to easily cope with a change in the thickness of the electrophotographic laminate.

Comparative Example In the exposure apparatus of Example 1, the charging device was fixed, and the electrophotographic laminate was charged by moving the surface plate (moving speed: 20 m / min). We tried to make a printed wiring board. When charging was performed with the applied voltage of the charging device and the height of the wire set to 6.0 kV and 15 mm, respectively, only a surface potential of 50 V was obtained. Furthermore, the surface potential was 150 V even when the applied voltage was 10 kV. When the height of the wire was further reduced from this state to 5 mm, it was possible to increase the surface potential to 230 V. When the charge amount was 230 V, a circuit pattern could be formed.

However, when the applied voltage is increased, not only there is a problem in safety maintenance of the device, but also it is easy to cause charging unevenness due to contamination of the wire, and it is easy to induce discharge breakdown of the photoconductive layer. There is a problem, and the degree of freedom of the charging conditions is extremely reduced, so that it is difficult to cope with electrophotographic laminates of various specifications.

[0029]

As described above, in the present invention, a printed wiring board is manufactured from an electrophotographic laminate having a metal conductive layer and a photoconductive layer on at least one surface of an insulating substrate in this order by electrophotography. In the step of performing, by using an electrophotographic printed wiring board exposure apparatus having a charging device capable of scanning on the surface plate and having a variable height,
It is possible to realize a uniform charged state regardless of the performance of the exposure apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of an electrophotographic printed wiring board exposure apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic printed wiring board exposure apparatus main body 2 Exposure part entrance 3 Surface plate 4 Electrophotographic laminate 5 Charging device 6 Charging device scanning mechanism 7 Charging device height adjustment mechanism 8 Surface electrometer measurement probe

Claims (1)

[Claims] 1. A stationary electrophotographic laminator in a flatbed type electrophotographic printed wiring board exposure apparatus for charging and exposing an electrophotographic laminate having a metal conductive layer and a photoconductive layer provided on at least one surface of an insulating substrate. An electrophotographic printed wiring board exposure apparatus, comprising: a charging means capable of scanning on a board and varying a distance from the surface of the electrophotographic laminated board.