Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-03-29
2001-04-17
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06217152
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink-transfer-type printer which transfers ink to a recording sheet (such as a plain paper) to form an image thereon, and more particularly to a film member to be employed in the ink-transfer-type printer.
One of the present inventors has proposed an ink-transfer-type printer as disclosed in Japanese laid-open patent publication No. Hei 10-329345 published on Dec. 15, 1998, which employs a film member having a plurality of pores extending in a direction of the thickness of the film member. One surface of the film member is arranged to contact a recording sheet while the other surface to face a thermal line head with holding ink therebetween.
The pores of the film member are designed to normally prevent the permeation of ink. However, in case the thermal line head generates heat based on print information, the heated portions of the film member become easy to be elastically deformed so that the pores in the heated portions become easy to be widened. Then, the pores allow the penetration of ink therethrough to be transferred onto a recording sheet contacted to the opposite side of the film member.
Thus, by moving a recording sheet, with keeping the contact with the film member surface, in the direction perpendicular to the thermal line head while the heat control of the thermal line head is being continuously performed based on print information, a two-dimensional ink image can be formed on a recording sheet.
In the above ink-transfer-type printer, in order to allow a recording sheet to slide on a film member, the friction coefficient of the film member surface to which a recording sheet contacts must be small. Further, a film member must have such a characteristic as that pores formed in the film member must become easy to be widened when heated. For satisfying the above requirements, a film member made of polytetrafluoroethylene (for instance, “Nifutoron” produced by Nitto Denko K.K.) has been employed.
With the above film member, however, sometimes trailings of ink on a recording sheet have occurred during printing operation. The reason why this occurs seems because polytetrafluoroethylene needs relatively large amount of heat to change the elasticity thereof, so that it takes time to close the pores of the film member after heat generation at the thermal line head is ceased, than allowed for performing clear printing.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved film member, the pores of which can be timely closed to prevent trailings of ink during printing operation, while having a small friction coefficient at the surface thereof.
For the above purpose, in accordance with the present invention, there is provided a film member adapted to be employed in an ink-transfer-type printer in which a film member having a plurality of pores is disposed between a recording sheet and ink, the ink and the film member being heated by a heating means so that the pores are selectively expanded to allow the ink to permeate the expanded pores to be transferred onto a recording sheet, the film member comprises: at least an integrated pair of layers, the uppermost layer of which is made of a low-friction material whose elasticity is changed when heated while the lowermost layer is made of an elastomer, the plurality of pores being formed to extend through the integrated layers.
The uppermost layer of the film member faces a recording sheet to contact therewith when employed in the ink-transfer-type printer, and it is preferable that the low-friction material is one of or the mixture of more than one of polytetrafluoroethylene, polydifluoroethylene, polyurethane and polyethylene.
The lowermost layer of the film member faces a thermal line head through ink, and it is preferable that the elastomer is one of or the mixture of more than one of silicon rubber, polyethylene, polypropylene, polyvinyl acetate, chloroprene, isoprene, polyurethane and polyamide.
With the above constituted film member, when it is employed in a ink-transfer-type printer, the elasticity of the uppermost layer is changed to allow the pores to be widened at the portions selectively heated, and the corresponding pores of the lowermost layer are widened by the expanding pressure of ink at the portions selectively heated, thereby allowing ink to permeate through the selected pores of the uppermost and lowermost layers. On the other hand, when selective heating is ceased, the elasticity of the uppermost layer returns to its normal state to prevent permeation of ink through the pores thereof, and the pores of the lowermost layer are closed as the expanding pressure of ink dismisses. Here, even if it is delayed for the pores of the uppermost layer to be closed, the permeation of ink can be timely prevented as the corresponding pores of the lowermost layers are closed immediately when the expanding pressure of ink dismissed.
Optionally, a plurality of fillers may be dispersed in the lowermost layer. That is, as the lowermost layer is made of an elastomer, some cracks may appear around the inner circumferential surfaces of the pores thereof after repeated usage thereof. If the cracks are progressed and extended in the lowermost layer, the durability of the lowermost layer will decrease and it becomes difficult to function as designed. In order to prevent it, a plurality of fillers are to be dispersed in the lowermost layer.
Preferably, each of the fillers is of a substantially cylindrical shape made of glass, and the amount of the fillers to be dispersed is in the range of 0.1 wt % to 20 wt % of the lowermost layer. More preferably, the amount of the fillers is to be in the range of 1 wt % to 5 wt %.
In the preferred embodiment, the lowermost layer of the film member is directly integrated with the uppermost layer.
REFERENCES:
patent: 10-799 (1998-01-01), None
patent: 10-147032 (1998-06-01), None
patent: 10-147031 (1998-06-01), None
patent: 10-193654 (1998-07-01), None
patent: 10-329345 (1998-12-01), None
Chiba Toru
Suzuki Minoru
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Tran Huan
LandOfFree
Film member for use in ink-transfer-type printer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Film member for use in ink-transfer-type printer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Film member for use in ink-transfer-type printer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2520265