Abstract:
A surface processing method for a casing is disclosed. The method includes the following steps: performing an anodic treatment to a casing material, drying the casing material and printing a pattern on the casing material via digital printing. The method can reduce the surface processing cost and provide the appearance of the object with diverse patterns or colors.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The non-provisional patent application claims priority to U.S. provisional patent application with Ser. No. 61/436,885 filed on Jan. 27, 2011. This and all other extrinsic materials discussed herein are incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The invention relates to a processing method and, more particularly, to a surface processing method for a casing. 
         [0004]    2. Related Art 
         [0005]    A casing of an electronic device is usually made of aluminum or aluminum alloy which is easy to be oxidized. Although the oxidation layer is a passivation layer, however, if it exposed in the air for a long time, the oxidation layer may peel off and lose the protection to electronic devices. Consequently, manufacturers usually utilize an anodic treatment on the casing made of the aluminum or the aluminum alloy. Since the aluminum and the aluminum alloy are easy to be oxidized, the anodic treatment is performed on the casing and forms an oxidation layer via electrochemistry treatment, thus to prevent a further oxidation of the material, and therefore to strengthen the mechanical property of the surface. Moreover, chemical reaction in the anodic treatment brings various colors and presents a better looking of the object. 
         [0006]    The object after the anodic treatment is conventionally colored via dip-dye, however, only single dye can be used in each dip-dye process. If the object is required to present two or more colors, complicated processes including screen coating, exposing, covering and cleaning has to be performed, which wastes too much manpower and resources. Furthermore, when one more color wants to be performed, the complicated processes described above should be repeated. Because of the high cost of the manufacture in multi-color as well as the complicated process, most anodic treated objects in the market are showed in single color. 
       SUMMARY OF THE INVENTION 
       [0007]    A surface processing method for a casing which decreases the casing manufacturing cost and presents more diverse patterns or colors on the casing is disclosed. 
         [0008]    The surface processing method for a casing includes following steps: performing an anodic treatment to a casing material, drying the casing material, and printing a pattern on the casing material via digital printing. 
         [0009]    In an embodiment, the casing material includes aluminum or aluminum alloy. 
         [0010]    In an embodiment, the digital printing is a non-impact printing. 
         [0011]    In an embodiment, the non-impact printing is performed with charged ink. 
         [0012]    In an embodiment, a plurality of holes is formed by the anodic treatment at the surface of the casing material. 
         [0013]    In an embodiment, the non-impact printing sprays out the charged ink, the charged ink passes through an electric field and fills into the holes according to the charges of the charged ink. 
         [0014]    According to the disclosure herein, if the casing material is required to present two or more colors, no more complicated processes including screen coating, exposing, covering and cleaning should be performed, and the cost of manpower, resources and time is reduced. Moreover, the surface processing method for a casing provides the casing material presenting in multi-colors and have advantages via using anodic treatment. More specifically, the printing ink and the resolution can be selected according to various requirements. The pattern can be printed automatically simply by inputting relating information, which is flexible, precise, and efficient, and provides the casing material with more diverse patterns and colors. 
         [0015]    These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a flow chart showing steps of the surface processing method for a casing in a first embodiment; 
           [0017]      FIG. 2  is a block diagram showing a surface processing system in a first embodiment; 
           [0018]      FIG. 3A  and  FIG. 3B  are schematic diagrams showing a casing material of the surface processing method for a casing in a first embodiment; 
           [0019]      FIG. 4  is a flow chart showing steps of the surface processing method for a casing in a second embodiment; 
           [0020]      FIG. 5  is a block diagram showing a surface processing system in a second embodiment; and 
           [0021]      FIG. 6  is a schematic diagram showing a casing material of the surface processing method for a casing in a second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    A surface processing method for a casing is illustrated below with relating figures, and the same symbols denote the same components. 
         [0023]      FIG. 1  is a flow chart showing steps of a surface processing method for a casing in a first embodiment, and  FIG. 2  is a block diagram showing a surface processing system  1  in a first embodiment. 
         [0024]    The surface processing method for a casing includes following steps: performing an anodic treatment to a casing material, drying the casing material, and printing a pattern on the casing material via digital printing. 
         [0025]    More specifically as shown in  FIG. 1 , the surface processing method for a casing includes the following steps: performing the anodic treatment to the casing material O to form a plurality of holes at the surface of the casing material O (S 01 ); drying the casing material O (S 02 ); and printing a pattern on the casing material O (S 03 ). 
         [0026]    As shown in  FIG. 2 , the surface processing system  1  for performing the surface processing method for a casing includes an anodic treatment device  11 , a heat treatment device  12  and a digital printing device  13 . The devices above can be integrated to a single system to simplify the process and save time, and they can also be operated independently, which is not limited herein. 
         [0027]    The casing material O may be a casing of an electronic product, and the material may be aluminum or aluminum alloy, which is not limited herein. In the embodiment, the aluminum is taken as an example. 
         [0028]      FIG. 3A  is a schematic diagram showing a casing material in a first embodiment. The anodic treatment device  11  performs an electrolysis and oxidation process on the surface of the casing material O by electrochemistry method. Then, an oxidation layer is formed at the surface of the casing material O to prevent the casing material O to be further oxidized. In the embodiment, the oxidation layer is aluminum oxide (Al 2 O 3 ). After the anodic treatment, a plurality of holes H are formed at the surface of the casing material O, which is so-called cellular tube layer  2 . 
         [0029]    After the anodic treatment, the surface of the casing material O is with moisture. In order to avoid the subsequent process is affected, a heat treatment is performed by the heat treatment device  12  to remove the moisture from the holes H of the cellular tube layer  2 . The moisture condition may be adjusted by demand, which is not limited herein. 
         [0030]    As showed in  FIG. 3B , ink M is sprayed to fill into the holes H of the cellular tube layer  2  by the digital printing device  13 , and the ink M may be in one color or a combination of multiple colors. Ink M is sprayed to fill into the holes H in a non-impact printing way. When the charged ink passes through an electric field, the charged ink with different charges will have different shift paths, and thus the non-impact printing method controls the position of each drop of the charged ink accordingly, and to fill the charged ink into the holes H. Since the ink is injected or sprayed out, the digital printing device  13  does not need to contact the casing material O. Consequently, the surface processing method for a casing disclosed herein has the advantages of high speed, high data variability and can be applied to various materials. In an embodiment, the digital printing device  13  may be an electronic printing device or an inkjet printing device, which is not limited herein. 
         [0031]      FIG. 4  is a flow chart showing steps of the surface processing method for a casing in a second embodiment, and  FIG. 5  is a block diagram showing a surface processing system la in a second embodiment. 
         [0032]    The surface processing method for a casing as showed in  FIG. 4  further includes a step of sealing the holes H of the cellular tube layer  2  (step S 04 ), which is different with that in  FIG. 1 . In an embodiment, the holes H of the cellular tube layer  2  are sealed by a sealing device  14  of the surface processing system  1   a.    
         [0033]    As shown in  FIG. 6 , the sealing device  14  may seal the holes H of the cellular tube layer  2  via vapor, boiling water or chemicals, which is not limited herein. In the embodiment, the holes H are sealed via high temperature. Thus, the surface of the casing material O includes three layers; a material layer (an aluminum layer), an oxidation layer with ink (a cellular tube layer  2 ) and a sealing layer  3  from bottom up. In the embodiment, the sealing layer  3  is an anodic coating layer which prevents the ink M peeled off from the casing material O. Furthermore, a sealing layer comprises other materials, such as nickel, may also be provided on the surface of the casing material O to prevent the ink M to be peeled off. 
         [0034]    After the sealing process is performed in the step S 04 , the surface processing method for a casing may further include a step of heating the casing material O up to dry the casing material O. 
         [0035]    The conventional casing manufacture process includes degreasing, alkali washing, chemical polishing, neutralization layer removing, anodic treatment, dying, sealing and heating, which is a complicated process. The casing material after the anodic treatment is usually colored via dip-dye, and only one single dye can be used in each dip-dye process. Thus, if the casing material is required to present two colors, the complicated processes including screen coating, exposing, covering and cleaning has to be performed, and when one more color is added, the complicated processes above should be repeated. 
         [0036]    The surface processing method for a casing in the embodiments provides the casing material presenting in multiple colors in a simple process, which includes the anodic treatment and the digital printing, and thus omits the complicated processes as described above. 
         [0037]    Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.