Patent Publication Number: US-2015086254-A1

Title: Image Forming Apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 USC 119 of Japanese patent application no. 2013-196863, filed on Sep. 24, 2013, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming apparatus configured to form an image on a paper with pigment. 
     2. Description of the Related Art 
     There is conventionally known an image forming apparatus including an image forming unit configured to form an image on a paper with pigment such as ink or toner and a heating unit configured to heat the pigment and the paper. Since the heating unit heats the paper or the like, the ink that adheres to the paper is dried or the toner is fused to the paper. 
     There is known an image forming apparatus configured to heat the pigment and the paper by applying microwaves. Furthermore, there is known an image forming apparatus configured to fuse the toner on the paper using a heat roller, but the image forming apparatus includes an auxiliary heating unit configured to heat the paper with microwaves to dry the paper before fusing. 
     Therefore, an object of the present invention is, in consideration of the above-described circumstances, to provide an image forming apparatus capable of efficiently heating pigment and a paper. 
     SUMMARY OF THE INVENTION 
     An image forming apparatus according to the present invention includes an image forming unit configured to form an image on a paper with pigment, a heating unit configured to heat the pigment and the paper from one or both surfaces of the paper, a microwave generator, and a microwave applicator arranged downstream of the heating unit and configured to heat the pigment and the paper by applying microwaves generated by the microwave generator. 
     With the image forming apparatus according to the present invention, the image forming unit forms the image on the paper with the pigment, and the heating unit heats the pigment and the paper from the one or both surfaces of the paper. Then, the microwave applicator arranged downstream of the heating unit heats the pigment and the paper with microwaves output from the microwave generator, and thus an interior portion and the like of the paper that have not been sufficiently heated by the heating unit can be heated. Therefore, the pigment and the paper can be efficiently heated. 
     In the image forming apparatus according to another embodiment of the present invention, the image forming unit forms the image on the one surface of the paper with wet-type pigment, and the heating unit heats the pigment and the paper from the other or both surfaces of the paper. 
     In the image forming apparatus according to another embodiment of the present invention, the heating unit is a heat roller configured to heat the paper from the other or both surfaces of the paper. 
     In the image forming apparatus according to another embodiment of the present invention, the microwave generator supplies power to the microwave applicator such that a temperature of the pigment that contains a moisturizing agent (for example, glycerin) is higher than a boiling temperature of the moisturizing agent. 
     In the image forming apparatus according to another embodiment of the present invention, the image forming unit forms the image on the one surface of the paper with dry-type pigment, and the heating unit heats the pigment and the paper from the one or both surfaces of the paper. 
     In the image forming apparatus according to another embodiment of the present invention, the heating unit is a heat roller configured to heat the paper from the one or both surfaces of the paper. 
     The image forming apparatus according to another embodiment of the present invention includes a pair of feed belts configured to sandwich and feed the paper. The microwave applicator includes a heat chamber into which microwaves output from the microwave generator are introduced to heat the pigment and the paper. The heat chamber includes a pair of openings through which the paper passes an interior portion of the heat chamber. The pair of feed belts passes through the pair of openings. 
     The image forming apparatus according to another embodiment of the present invention includes a plurality of feed rollers with the feed belt provided around each outer circumference thereof to cause the pair of feed belts to travel. The heating unit is a heat roller configured to heat the paper from the one or both surfaces of the paper and is one of the plurality of feed rollers. 
     In the image forming apparatus according to another embodiment of the present invention, the feed belt is heat-resistant and has a mold release property. 
     As described above, the image forming apparatus according to the present invention provides an excellent effect in that the pigment and the paper can be efficiently heated. 
     Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating main portions of an image forming apparatus according to a first embodiment of the present invention. 
         FIG. 2  is a schematic drawing illustrating a microwave applicator according to the first embodiment. 
         FIG. 3  is a schematic diagram illustrating a heat chamber of the microwave applicator according to the first embodiment. 
         FIG. 4  is an overall schematic drawing illustrating an image forming apparatus according to a second embodiment of the present invention. 
         FIG. 5  is a schematic diagram illustrating main portions of the image forming apparatus according to the second embodiment. 
         FIG. 6  is a schematic diagram illustrating main portions of an image forming apparatus according to a further embodiment of the present invention. 
         FIG. 7  is a schematic diagram illustrating main portions of an image forming apparatus according to a further embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A First Embodiment 
     A first embodiment of an image forming apparatus according to the present invention will be hereinafter described with reference to  FIGS. 1 to 3 . 
     As illustrated in  FIG. 1 , an image forming apparatus  1  according to the present embodiment includes a paper feed unit  2  configured to feed a paper  100  along a feed direction D1, an image forming unit  3  configured to form an image on the paper  100  with wet-type pigment  101 , and a drying unit  4  configured to dry the wet-type pigment  101 . In the present embodiment, the pigment  101  is an ink  101  that contains glycerin. 
     The paper feed unit  2  includes a supplying unit  21  configured to supply the paper  100  and a recovery unit  22  configured to recover the paper  100  on which the image has been formed. The image forming unit  3  includes a nozzle unit  31  configured to discharge the ink  101  onto one surface of the paper  100 . 
     The drying unit  4  includes a heating unit  5  configured to heat the ink  101  and the paper  100  from both surfaces of the paper  100 . In addition, the drying unit  4  includes a microwave applicator  6  configured to heat the ink  101  and the paper  100  with microwaves. The microwave applicator  6  is arranged downstream of the heating unit  5 . 
     The heating unit  5  includes a heat roller  51  configured to make contact with the other surface of the paper  100  to heat the ink  101  and the paper  100  from the other surface of the paper  100 . In addition, the heating unit  5  includes a hot-air heater  52  configured to blow hot air towards the one surface of the paper  100  to heat the ink  101  and the paper  100  from the one surface of the paper  100 . 
     The heat roller  51  includes a cylindrical roller unit  51   a  formed of metal or the like, for example, and heat source  51   b  arranged inside of the roller unit  51   a  and configured to heat the roller unit  51   a.  In the present embodiment, the heat source  51   b  is a halogen lamp. Since the heat generated from the heat source  51   b  is propagated to the other surface of the paper  100  via the roller unit  51   a,  the ink  101  and the paper  100  are heated from the other surface of the paper  100 . 
     As illustrated in  FIGS. 2 and 3 , the microwave applicator  6  includes a microwave generator  61  formed of a magnetron that outputs microwaves, and a power supply  62  configured to supply power to the microwave generator  61 . The microwave applicator  6  includes a heat chamber  63  into which the microwaves output from the microwave generator  61  are introduced to heat the ink  101  and the paper  100 , and a tuner  64  arranged between the microwave generator  61  and the heat chamber  63 . 
     The microwave applicator  6  includes an isolator  65  arranged between the microwave generator  61  and the tuner  64 . The isolator  65  is a protection equipment configured, in a case in which microwaves are reflected from the tuner  64  in a direction of the microwave generator  61 , to convert power of the reflected microwaves into thermal energy and to stably operate the microwave generator  61 . 
     In the microwave applicator  6 , since the power source  62  supplies prescribed power to the microwave generator  61 , the ink  101  and the paper  100  reach a temperature (for example, 200° C.) close to a boiling temperature of glycerin or preferably high temperature (for example, 300° C.). Therefore, since the glycerin serving as a moisturizing agent evaporates from the ink  101  heated by the microwave applicator  6 , the ink  101  can be more dried. 
     The heat chamber  63  includes a heat chamber main body  63   a  formed into a square-tube shape, and a partition plate  63   e  that partitions the heat chamber main body  63   a  into a plurality of (three in the present embodiment) rooms  63   b  to  63   d  along the feed direction D1. The heat chamber  63  includes a short-circuited  plate  63   f  configured to reflect the microwaves introduced from the microwave generator  61  to form standing waves W1 to W3. 
     The heat chamber  63  includes a plurality of dielectrics  63   g  having permittivity higher than air such that phases of the respective standing waves W1 to W3 of the rooms  63   b  to  63   d  are shifted from each other by one sixth of a wavelength. Furthermore, the heat chamber  63  includes a pair of openings  63   h,    63   h  through which the paper  100  passes an interior portion of the heat chamber  63 . 
     As described above, with the image forming apparatus  1  according to the present embodiment, the image forming unit  3  forms an image on the paper  100  with the ink  101 . The heating unit  5  heats the ink  101  and the paper  100  from both surfaces of the paper  100 . Specifically, a hot-air heater  52  heats the one surface of the paper  100  on which the ink  101  has been discharged, and the heat roller  51  heats the other surface of the paper  100 . 
     Then, the microwave applicator  6  arranged downstream of the heating unit  5  heats the ink  101  and the paper  100  with the microwaves output from the microwave generator  61 . Consequently, an interior portion of the paper  100  that has not been sufficiently heated by the heating unit  5  and the ink  101  that has infiltrated in the interior portion of the paper  100  can be heated. The ink  101  and the paper  100  thus can be efficiently heated. 
     A Second Embodiment 
     Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to  FIGS. 4 and 5 . In  FIGS. 4 and 5 , parts denoted by the same reference numerals as  FIGS. 1 to 3  indicate the same configurations or elements as the first embodiment. 
     As illustrated in  FIG. 4 , an image forming apparatus  10  includes a paper feed unit  20  configured to feed a paper  100 , an image forming unit  30  configured to form an image on the paper  100  with dry-type pigment  102 , and a fuser  40  configured to fuse the dry-type pigment  102  on the paper  100 . In addition, the image forming apparatus  10  includes an apparatus main body  8  configured to accommodate each unit  20 ,  30 , and  40  therein, and a document scanning unit  9  configured to scan a document. In the present embodiment, the pigment  102  is a toner  102 . 
     The paper feed unit  20  includes a cassette  25  configured to accommodate layered papers  100  therein and inserted in a lower part of the apparatus main body  8 , and a pick-up roller  26  configured to feed a compressed uppermost paper  100  of the layered papers  100 . In addition, the paper feed unit  20  includes a lifting plate  27  configured to press the paper  100  against the pick-up roller  26  by urging an end portion thereof upward, and a paper exit roller  28  configured to discharge the paper  100  on which the image has been formed by the image forming unit  30  and the fuser  40  towards a paper exit tray  81  of the apparatus main body  8 . 
     The image forming unit  30  includes a cylindrical photoconductive drum  34  configured to form a photoconductor on a surface thereof, and a charger  35  configured to evenly charge the surface of the photoconductive drum  35 . In addition, the image forming unit  30  includes an exposure unit  36  configured to expose the surface of the photoconductive drum  34  based on image data and the like scanned by the document scanning unit  9 , and a developing unit  37  configured to cause the toner  102  to adhere to the surface of the photoconductive drum  34 . Furthermore, the image forming unit  30  includes a transfer unit  38  configured to transfer the toner  102  that adheres to the surface of the photoconductive drum  34  to one surface of the paper  100 . 
     As illustrated in  FIG. 5 , the fuser  40  includes a heating unit  50  configured to heat the toner  102  and the paper  100  from the one surface of the paper  100 , and the microwave applicator  6  configured to heat the toner  102  and the paper  100  with microwaves. Furthermore, the fuser  40  includes a feed device  7  configured to feed the paper  100  along the feed direction Dl. 
     The heating unit  50  includes the heat roller  51  configured to make contact with the one surface of the paper  100  to heat the toner  102  and the paper  100  from the one surface of the paper  100 . In addition, the heating unit  50  includes a press roller  55  configured to make contact with the other surface of the paper  100  to press the paper  100  against the heat roller  51 . 
     The microwave applicator  6  includes the microwave generator  61 , the power supply  62 , the heat chamber  63 , the tuner  64 , and the isolator  65  (only the heat chamber  63  is illustrated in  FIG. 5 ). Since configurations of each unit  6 , and  61  to  65  are substantially same as configurations of each unit  6 , and  61  to  65  according to the above-described first embodiment, redundant explanation will be omitted. 
     The feed device  7  includes a pair of feed belts  71 ,  72  configured to sandwich and feed the paper  100 . In addition, the feed device  7  includes a plurality of (four in the present embodiment) feed rollers  73  with the first feed belt  71  provided around each outer circumference of the feed rollers  73  to cause the first feed belt  71  to travel, and a plurality of (four in the present embodiment) feed rollers  74  with the second feed belt  72  provided around each outer circumference of the feed rollers  74  to cause the second feed belt  72  to travel. 
     The pair of feed belts  71 ,  72  is arranged so as to pass through the pair of openings  63   h,    63   h  provided in the heat chamber  63 . The first feed belt  71  is in contact with the one surface of the paper  100 , and the second feed belt  72  is in contact with the other surface of the paper  100 . In the present embodiment, each feed belt  71 ,  72  is formed of polyimide film coated with polytetrafluoroethylene (PTFE). 
     As described above, with the image forming apparatus  10  according to the present embodiment, the image forming unit  30  forms the image on the one surface of the paper  100  with the toner  102 , and the heating unit  50  heats the toner  102  and the paper  100  from the one surface of the paper  100 . Then, the microwave applicator  6  arranged downstream of the heating unit  50  heats the toner  102  and the paper  100  with microwaves output from the microwave generator  61 . 
     Consequently, an interior portion of the paper  100 , the other surface of the paper  100 , and the like that have not been sufficiently heated by the heating unit  50  can be heated. The toner  102  and the paper  100  thus can be efficiently heated. 
     The image forming apparatus according to the present invention is not limited to configurations of the above-described embodiments or effects described above, and it is needless to mention that various modifications may be made within the scope as long as these do not depart from the essence of the present invention. For example, each configuration and each method of the above-described embodiments may be freely adopted and combined, and each configuration and each method according to one exemplary embodiment may be applied to those according to other exemplary embodiments. It is also needless to mention that any of the configurations and the methods concerning the following modifications may be selected to apply to the configurations and the methods according to the above-described embodiments. 
     In the image forming apparatus  10  according to the above-described second embodiment, the heating unit  50  and the feed device  7  are mechanisms separated from each other. However, the image forming apparatus  10  according to the present invention is not limited to such a configuration. Specifically, in the image forming apparatus  10  according to the present invention, a part or all parts of the heating unit  50  and the feed device  7  may be used in common. 
     For example, in the image forming apparatus according to a further embodiment of the present invention, as illustrated in  FIG. 6 , the heat roller  51  of the heating unit  50  may double as the feed roller  73  to cause the first feed belt  71  to travel, and the press roller  55  of the heating unit  50  may double as the feed roller  74  to cause the second feed belt  72  to travel. With such a configuration, the heat roller  51  heats the paper  100  from the one surface via the first feed belt  71 . 
     Furthermore, in the image forming apparatus according to a further embodiment of the present invention, as illustrated in  FIG. 7 , for example, the press roller  55  of the heating unit  50  may double as the feed roller  74  to cause the second feed belt  72  to travel. Although not illustrated, in the image forming apparatus according to the present invention, for example, the heat roller  51  of the heating unit  50  may double as the feed roller  73  to cause the first feed belt  71  to travel. 
     In the image forming apparatus  1  according to the above-described first embodiment, the heating unit  5  includes the heat roller  51  and the hot-air heater  52 . In the image forming apparatus  10  according to the above-described second embodiment, the heating unit  50  includes the heat roller  51  and the press roller  55 . However, the image forming apparatus according to the present invention is not limited to such configurations. For example, in the image forming apparatus according to the present invention, a heating unit may be formed only by the heat roller  51  or only by the hot-air heater  52 . Alternatively, the heating unit may be formed of an infrared ray irradiation device using an electronic flash. 
     Furthermore, the image forming apparatus  1  according to the above-described first embodiment is an ink jet printing machine. The image forming apparatus  10  according to the above-described second embodiment is a toner printing machine. However, the image forming apparatus according to the present invention is not limited to such configurations. For example, the image forming apparatus according to the present invention may be a relief printing machine using a relief printing plate, an offset printing machine using a flat plate, an intaglio printing machine using an intaglio plate, or a stencil printing machine such as a silkscreen printing machine or a mimeograph. 
     While the present invention has been described with respect to embodiments thereof, it will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than those specifically set out and described above. Accordingly, the appended claims cover all modifications that fall within the true spirit and scope of the present invention.