Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2001-02-16
2002-06-18
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
Reexamination Certificate
active
06406141
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink drier for drying an ink on a paper after image formation and an ink jet type image forming apparatus mounting the ink drier, and more particularly, to an ink drier comprising a semicylindrical paper drying passageway for upward inverting a paper conveyed immediately after printing and a heat source provided on the central side of a circular arc of the semicylindrical paper drying passageway, and an ink jet type image forming apparatus mounting the ink drier.
2. Description of the Prior Art
In an ink jet type image forming apparatus, a time required for drying an ink after image formation considerably influences an efficiency of a whole printing process. In particular, a pigment based black ink capable of easily obtaining high picture quality generally requires a long time for drying. Therefore, in the case of an image having a high area ratio of a black dot such as a black solid, a long time is required for drying the ink, thereby deteriorating an increase in the speed of a printing operation. On the other hand, if the speed of the printing operation is increased carelessly, a conveying roller comes in contact with a print surface of a paper or the paper is mounted on a discharge tray in such a state that the ink is dried:incompletely, for example. Consequently, there is a drawback that the print surface or back face of the paper is stained with the ink.
For example, Japanese Patent Application Laid-Open Sho 63 No.252772 has proposed an ink jet type printer mounting an ink drier for drying a paper immediately after printing.
As shown in
FIG. 1
, a printer Z
0
proposed in the above-mentioned publication comprises a paper tray
51
for storing a print paper, a pinch roller
52
for conveying the paper in the paper tray
51
one by one, an ink jet type print head
53
for forming an image on the paper conveyed by the pinch roller
52
, a semicylindrical paper drying passageway
54
for upward inverting the paper on which an image is formed by the print head
53
, an infrared heat source
55
provided in the vicinity of the center of a circular arc of the paper drying passageway
54
, a reflecting plate
56
provided on the rear face side of the infrared heat source
55
with respect to the paper drying passageway
54
, a discharge roller
57
for discharging the paper conveyed along the paper drying passageway
54
, and a discharge tray
58
for accumulating the paper discharged through the discharge roller
57
.
A series of printing processes in the printer Z
0
will be briefly described below. First of all, one uppermost paper mounted in the paper tray
51
is taken out and is conveyed at a constant speed below the print head
53
through the pinch roller
52
. In that case, the print head
53
forms an image on the paper while carrying out a scan in a direction orthogonal to a paper conveying direction. The paper sequentially enters the paper drying passageway
54
from a portion where an image is formed by the print head
53
, and is conveyed along the semicylindrical paper dying passageway
54
. At this time, an ink on the paper is dried with infrared rays directly irradiated from the infrared heat source
55
or infrared rays reflected by the reflecting plate
56
and indirectly irradiated. The paper having the ink dried which is conveyed along the paper drying passageway
54
is discharged onto the discharge tray
58
through the discharge roller
57
.
The printer Z
0
mounts an ink drier comprising the semicylindrical paper drying passageway
54
, the heat source
55
, the reflecting plate
56
and the like. Therefore, a black solid image formed by a lazy drying black ink can also be dried in a short time, for example. Thus, it is possible to increase the speed of a printing operation while maintaining high picture quality. Moreover, the paper is inverted upward and discharged along the semicylindrical paper drying passageway
54
. Consequently, there are also advantages that the size of the device can be reduced and the paper can be mounted in correct order.
In the conventional printer Z
0
, however, only the pinch roller
52
and the discharge roller
57
are provided on the upstream and downstream sides of the paper drying passageway
54
as conveying means for conveying the paper along the paper drying passageway
54
. Accordingly, the paper basically conforms to an internal surface with only the rigidity of the paper itself over the paper drying passageway
54
. In the case of a paper having a small rigidity such as a thin sheet or a paper in a high humid state, accordingly, a tip thereof droops down by self weight during conveying over the paper drying passageway
54
. Consequently, there is a fear that a paper jam might be caused and the paper might come in contact with the heat source
55
, thereby catching fire in the worst case.
With the above-mentioned structure, furthermore, a paper having a smaller size than a path length between the pinch roller
52
and the discharge roller
57
cannot be used.
If such a paper is used by mistake, there is a fear that the paper jam might be caused or the paper might come in contact with the heat source
55
, thereby catching fire in the same manner as in the case in which the paper having a small rigidity is used.
Moreover, the heat source is provided in the vicinity of the center of the circular arc of the semicylindrical paper conveying passageway. Therefore, heat is uniformly irradiated over the whole paper conveying passageway so that a constant time or more is required for drying an ink. For this reason, there is also a problem in that a drying path length is determined by the drying time and the size of the apparatus cannot be reduced.
SUMMARY OF THE INVENTION
In consideration of the above-mentioned circumstances, it is an object of the present invention to provide an ink drier capable of normally and safely drying an ink on a paper having a small rigidity or a paper having a small size without disadvantages such as a paper jam or an ignition caused by a contact with a heat source, and an ink jet type image forming apparatus mounting the ink drier.
In order to achieve the above-mentioned object, the present invention has the following aspects.
A first aspect of the present invention is directed to an ink drier comprising a semicylindrical paper drying passageway for upward inverting a paper conveyed immediately after printing, a heat source provided on a central side of a circular arc of the paper drying passageway, and paper holding means for continuously holding the paper along the paper drying passageway.
A second aspect of the present invention is directed to the ink drier according to the first aspect, wherein more heat energy sent from the heat source is irradiated onto a paper input side of the paper drying passageway than a paper output side thereof.
A third aspect of the present invention is directed to the ink drier according to the second aspect, wherein the heat source is provided closer to the paper input side than the center of the circular arc of the paper drying passageway.
A fourth aspect of the present invention is directed to the ink drier according to the second aspect, further comprising a reflecting plate provided on a rear face side of the heat source with respect to the paper drying passageway and serving to reflect more heat energy which is not used for paper drying but is dissipated toward the paper input side of the paper drying passageway than the paper output side thereof.
A fifth aspect of the present invention is directed to the ink drier according to the third aspect, further comprising a reflecting plate provided on a rear face side of the heat source with respect to the paper drying passageway and serving to reflect more heat energy which is not used for paper drying but is dissipated toward the paper input side of the paper drying passageway than the paper output side thereof.
A sixth aspect of the present invention is directed to the ink drier according to the first aspect, wherein the pa
Akagawa Yu-hi
Koyama Kazuya
Yamada Masanori
Yosimura Hisasi
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