Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1998-06-17
2001-03-06
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S018000
Reexamination Certificate
active
06196672
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink-jet printer using hot-melt type ink and capable of heating a recording medium such as a paper and cooling the recording medium after the hot-melt type ink has been printed on the recording medium.
A conventional hot-melt type ink-jet printer includes a recording head mounted on a carriage. The recording head includes a nozzle head having a plurality of nozzles, an ink melting section including a heater, and a hopper for storing solid ink pellets. Further, a platen is provided in confrontation with the nozzle head for supporting the recording medium. The carriage is moved in a main scanning direction orthogonal to a recording medium feeding direction, while hot-melt ink droplets are ejected from the nozzles in the nozzle head to form images such as characters and graphs on the surface of the recording medium. The hot melt ink, once printed on a print medium, is extremely durable and has a weather proof characteristic. Hot-melt ink liquefies when heated and hardens at room temperature. Therefore, to print using hot melt ink, the hot melt ink in the print head is heated and melted before it is ejected from the print head.
If the hot-melt ink is ejected from the nozzle heads onto the surface of the recording medium having a relatively low temperature, the ink droplet is immediately solidified at the surface. Therefore, ink fixing property on the recording medium may be lowered. Thus, the solidified ink may be easily peeled off from the surface of the recording medium to degrade the imaging quality. In this connection, the recording medium must be sufficiently heated prior to the ink ejection. To this effect, conveying speed of the recording medium must be low prior to the printing operation to obtain sufficient heat transmission to the recording medium. As a result, high speed printing cannot be performed.
If the hot-melt ink is ejected onto pre-heated recording medium having a prescribed elevated temperature, the fixing properties of the ink on the recording medium can be improved. However, downstream of the recording head, the recording medium continues to be fed between a discharge roller and a pinch roller. If the hot-melt ink fixed on the recording medium has not solidified completely before passing through these rollers, some of the ink is transferred to the pinch roller and the like, thereby reducing the quality of the printed image.
In order to avoid these problems, in a subsequent conventional printer, a heater is provided at a back side of the platen opposite a side along which the recording medium passes for increasing the temperature of the recording medium. Further, a sheet conveying distance between the platen and a discharge section including the discharge roller and the pinch roller is designed to be longer to allow the recording medium just printed to cool while being conveyed over this longer distance. This allows the hot-melt ink to solidify before reaching the discharge section.
However, in order to lengthen the conveying distance, it is necessary to increase the overall dimensions of the printer. Moreover, if the conveying speed of the recording medium is increased after printing operation, the time required to convey the recording medium from the printing portion to the discharge section is essentially decreased. As a result, it is impossible to achieve the cooling effect when performing high-speed printing on a printer of this construction and, therefore, impossible to achieve an image of desirable quality.
Further, in a conventional hot-melt type ink jet printer, a power board is provided in a main case of the printer. Since a temperature of the power board tends to be elevated, a cooling fan is provided in the main case to cool the power board by blowing air on the same. The cooling fan is disposed in a wall of the main case, from which location external air can be easily taken in or expelled.
U.S. Pat. No. 5,005,025 discloses an ink jet printer having a heater whose upstream part serves as a platen and whose downstream part extending to a discharge roller. Because the heater provides an elongated conveying path, sufficient heat can be transmitted to the recording medium for improving fixation.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a hot-melt type ink jet printer compact in size and capable of performing high speed printing yet maintaining high imaging quality.
Further, attention is drawn to the utilization of the cooling fan which conventionally is used for cooling the power board. In the present invention, the recording medium must be sufficiently heated immediately before the ink ejection for improving the image-fixing. On the other hand, the fixed inked image must be immediately cooled to avoid ink transfer to the sheet discharge section. Thus, another object of the present invention is to provide the hot-melt type ink jet printer including the cooling fan which generates a stream of air for cooling not only the power board but also the recording medium so as to promote cooling of the recording medium, thereby allowing the formation of high quality images on the recording medium even during high-speed printing.
Still another object of the present invention is to provide such printer capable of providing a suitable heating temperature, a suitable cooling temperature, a suitable printing speed of the recording medium and a suitable discharge timing of the recording medium.
Still another object of the present invention is to provide such printer capable of performing efficient cooling to a power board provided in a printer frame.
These and other objects of the present invention will be attained by providing a hot-melt type ink jet printer for forming an inked image on an image receiving medium including a frame, a nozzle head, a main platen, a cooling platen, and a discharge roller. The nozzle head is movable relative to the frame and ejects a hot-melt ink onto the image receiving medium. The main platen has one surface in confrontation with the nozzle head. The image receiving medium is fed in a feeding direction along the one surface. The cooling platen is positioned downstream of the main platen in the feeding direction for cooling the inked image formed on the image receiving medium. The discharge roller is disposed downstream of the cooling platen for discharging the image receiving medium. The frame havs has a sheet discharge opening adjacent the discharge roller. An order of the main platen, the cooling platen and the discharge roller defines a sheet feed passage.
In another aspect of the invention, there is provided a hot-melt type ink jet printer for forming an inked image on an image receiving medium including a frame having a front side and a rear side, a nozzle head, a main platen, a main heater, a second platen, a fan, and a power board. The nozzle head is movable relative to the frame and ejects a hot-melt ink onto the image receiving medium. The main platen has one surface in confrontation with the nozzle head. The image receiving medium is fed in a feeding direction along the one surface. The main heater is provided at the opposite surface of the main platen for heating the main platen. The second platen is disposed immediately downstream of the main platen. A combination of the main platen and the second platen defines a sheet feed passage extending toward the front side of the frame. A first suction port is formed between the main platen and the second platen for introducing a cooling air into an interior of the frame through the first suction port. A second suction port is formed at the front side of the frame. The first suction port is open to the sheet feed passage and the second suction port is open to the front side. The fan is positioned at an intermediate portion between the front side and the rear side of the frame. The power board is positioned between the fan and the rear side of the frame. The power board is cooled by the cooling air introduced into the frame by the fan through the first suction
Asano Kazuya
Igarashi Hiroshi
Ito Noritsugu
Kamimura Naoya
Kimura Shinji
Brother Kogyo Kabushiki Kaisha
Le N.
Nguyen Judy
Oliff & Berridg,e PLC
LandOfFree
Hot-melt type ink jet printer having heating and cooling... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hot-melt type ink jet printer having heating and cooling..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hot-melt type ink jet printer having heating and cooling... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2506688