VACUUM FORMING MACHINE AND METHOD OF MAKING VACUUM FORMED PRODUCT
The present invention relates to a vacuum forming machine for attaching a decorative sheet onto a base member under a reduced pressure while forming the sheet and also relates to a method of making such a vacuum formed product.
Such a decorative sheet is attached onto a base member while the decorative sheet is being formed under a reduced pressure so as to trace the surface shape of the base member. A vacuum forming machine for performing such a vacuum forming process is disclosed in Japanese Patent Application Laid-Open Publications No. 2006-7422 and No. 63-214424, for example. By using such a vacuum forming machine, a vacuum formed product, in which the decorative sheet has been attached onto the surface of the base member, can be obtained.
When the decorative sheet is attached, the pressure inside the vacuum forming machine is reduced rapidly as a result of evacuation. That is why a violent air drag will generate a lot of static electricity on the surface of the base member, thus adsorbing dust, which has been settled inside the vacuum forming machine, onto the surface of base member. Consequently, if a vacuum forming process is carried out, the final vacuum formed product will contain dust between the base member and the decorative sheet. Since the humidity is low in winter, in particular, static electricity is generated easily and the fine appearance tended to be ruined quite often. Also, if the decoration layer of the decorative sheet includes a metal layer, then the optical reflectance at the surface of the vacuum formed product will be so high that even a minor degree of unevenness, which will have been caused on the decoration layer (i.e., the metal layer) by the adsorption of the dust, will ruin the fine appearance noticeably and destroy its aesthetic quality and beautiful appearance.
In this manner, the accumulation of dust caused by the static electricity that has been generated on the surface of the base member will ruin the appearance of a vacuum formed product. To overcome such a problem, that static electricity generated on the surface of the base member should be removed in one way or another.
Furthermore, Japanese Patent Application Laid-Open Publication No. 58-90925 discloses a bonded lens in which a glass lens and a polymer sheet have been stacked one upon the other, and teaches removing dust and preventing the generation of static electricity by blowing deionized air onto the inner surface of the glass substrate just before the polymer sheet is bonded onto the glass lens.
Accordingly, preferred embodiments of the present invention provide a vacuum forming machine that prevents dust, which could otherwise be gathered on the surface of a base member during a vacuum forming process using a decorative sheet, from ruining the appearance of a vacuum formed product to be obtained by that process.
A vacuum forming machine according to a preferred embodiment of the present invention is designed to attach a decorative sheet onto a base member under a reduced pressure while forming the sheet, and preferably includes a chamber configured to be loaded with the base member and the decorative sheet and including an exhaust port, an exhauster arranged to exhaust air from inside the chamber through the exhaust port, at least one static remover arranged to remove static electricity from the surface of the base member that has been loaded into the chamber, and a dust collector arranged so as to oppose the exhaust port.
A method of making a vacuum formed product according to yet another preferred embodiment of the present invention includes the steps of preparing a decorative sheet and a base member, and attaching the decorative sheet onto the base member in a chamber. The method further includes the steps of loading the base member into the chamber, exhausting air from inside the chamber in which the base member has been loaded, removing static electricity from the surface of the base member that has been loaded into the chamber, and collecting dust from inside of the chamber.
The vacuum forming machine according to a preferred embodiment of the present invention further includes a dust collector, which is arranged so as to oppose an exhaust port. That is why when the air is exhausted from a chamber by an exhauster, the air needs to go around (or bypass) the dust collector. As a result, violent drag is produced between the dust collector and the air, thereby electrifying the dust collector. Then, the dust inside the chamber is adsorbed onto the dust collector and collected there. Consequently, the accumulation of the dust onto the surface of the base member can be prevented more reliably and completely. By using the static remover and the dust collector in this manner, the vacuum forming machine according to a preferred embodiment of the present invention can avoid the unwanted situation where the dust gathered on the surface of the base member ruins the appearance of the resultant vacuum formed product as is often the case with the prior art.
The vacuum forming machine according to a preferred embodiment of the present invention preferably further includes an elevating mechanism arranged to raise or lower the decorative sheet with respect to the base member in the chamber. In that case, the static remover(s) is preferably located outside of the region in which the decorative sheet and/or the base member are/is raised or lowered by the elevating mechanism (such a region will be referred to herein as a “forming region”). By arranging the static remover(s) outside of the forming region, it is possible to prevent the static remover(s) from interfering with the forming process (e.g., to avoid an unwanted situation where the decorative sheet becomes attached to the static remover unintentionally). Also, at least a portion of the static remover(s) is preferably located at a height between the decorative sheet and the base member that are spaced farthest apart from each other by the elevating mechanism. By arranging at least a portion of static remover(s) between the decorative sheet and the base member that are farthest apart from each other, static electricity can be removed effectively.
The elevating mechanism may include a holder arranged to hold the decorative sheet so that the sheet is ready to be raised or lowered, for example. Alternatively, the elevating mechanism may include a supporting stage arranged to support the base member so that the base member is ready to be raised or lowered.
The vacuum forming machine according to a preferred embodiment of the present invention may further include an electrifier arranged to electrify the dust collector. By electrifying the dust collector via the electrifier securely, dust can be collected more perfectly.
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