Incremental printing of symbolic information – Thermal marking apparatus or processes – Having an intermediate medium for transferring ink
Reexamination Certificate
2002-09-30
2004-03-30
Tran, Huan Huu (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Having an intermediate medium for transferring ink
C347S222000
Reexamination Certificate
active
06714227
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus and method, and a transferring medium cassette used in the image forming apparatus. The image forming apparatus and method utilize an indirect transferring method, in which a record-image is once formed on an intermediate transferring medium, then a layer including the formed record-image is transferred from the intermediate transferring medium to a target object, which requires image formation, such as a card-, sheet-, booklet-, or disk-like object (though the shape is not necessarily limited).
2. Description of the Related Art
An indirect transferring method is known, in which a mirror image of a record-image is formed on the image-forming layer of an intermediate transferring medium, and then the record-image is transferred onto a target object to form a normal image of the record-image. In this method, for example, the used intermediate transferring medium is formed of an intermediate transfer film having a film-like long substrate and the image-forming layer, which is disposed on the substrate and capable of being transferred onto the target object by separation from the substrate. For example, this method is utilized along with an image forming technique for forming a gradated and especially multi-colored image by means of thermal fusion transfer, thermally adhesive film separation transfer or the like, using a dot-on-dot method (a method of stacking differently colored dots one on another at substantially the same position to obtain a predetermined color) and an area gradation method (a method of setting gradations based on the dot sizes in pixels), or by means of sublimation transfer using a density gradation method, which utilizes thermal sublimation of sublimation dyes.
Specifically, in the primary transfer, only the ink layer of an ink ribbon, or sublimation dyes for sublimation transfer are selectively transferred to an intermediate transfer film by a thermal head, so that a record-image is formed. Then, the intermediate transfer film with the record-image is put on a target object, and is supplied with heat and pressure by a heating and pressing mechanism to perform the secondary transfer. By doing so, the record-image is transferred along with the image-forming layer from the intermediate transfer film onto the target object. Then, the intermediate transfer film is separated from the target object, so that the transfer of the record-image onto the surface of the target object is completed.
With this method, it is possible to transfer a record-image onto various kinds of objects, such as paper materials (normal paper, fine quality paper, art paper, synthetic paper, processed paper, etc.), plastic goods, metal goods, glass materials, and ceramics. Accordingly, an image can be formed on various kinds of target objects, such as booklets, e.g., bankbooks and passports, and other items, of, e.g., sheet or card.
FIG. 1
is a schematic structural view showing an image forming apparatus using a conventional indirect transferring method, while putting emphasis on the path of an intermediate transfer film and an ink ribbon in use.
As shown in
FIG. 1
, an intermediate transfer film
3
and an ink ribbon
4
pass between a thermal head
1
and a platen roller
2
, which work as an image forming mechanism. The ink ribbon
4
is selectively heated by the thermal head
1
while the intermediate transfer film
3
and the ink ribbon
4
are put one on the other on the platen roller
2
, so that a mirror image of a record-image is formed on the image-forming layer
10
(see
FIG. 9
) of the intermediate transfer film
3
.
The intermediate transfer film
3
further passes between a heating roller
5
and a pressure roller
6
, which work as a heating and pressing mechanism, and is set in a state where it is put around a guide roller
7
and a separation roller
8
. A target object
9
is set on the right side in
FIG. 1
, and is sent between the heating roller
5
and the pressure roller
6
. The intermediate transfer film
3
and the target object
9
are supplied with heat and pressure between the heating roller
5
and the pressure roller
6
, so that the image-forming layer
10
of the intermediate transfer film
3
is transferred along with the record-image onto the target object
9
.
In such an image forming apparatus, especially when the intermediate transfer film
3
is set, there is a case where the intermediate transfer film
3
is set at an improper position in the width direction, thereby disturbing the path of the film.
FIG. 2
is a perspective view showing a setting method of the intermediate transfer film
3
, using the method above. When the intermediate transfer film
3
is replaced, the distal end of the outermost surface of the intermediate transfer film
3
is first fixed to a take-up reel
11
by a fixing tape
15
or the like. Then, a pay-off reel
13
is put and set on a pay-off axis connector
14
provided in the apparatus. Then, the take-up reel
11
is put and set on a take-up axis connector
12
provided in the apparatus, thereby completing the setting.
In another setting method (not shown), the pay-off reel
13
is first put and set on the pay-off axis connector
14
provided in the apparatus. Then, the take-up reel
11
is put and set on the take-up axis connector
12
. Then, the distal end of the outermost surface of the intermediate transfer film
3
is fixed to the take-up reel
11
by a fixing tape
15
or the like, thereby completing the setting.
In either case of the setting methods described above, since the path of the intermediate transfer film
3
is long and not linear, it is difficult to properly (accurately) set the orientation of the transfer film at the position fixed by the fixing tape
15
, thereby likely causing variations therein. Consequently, as shown in
FIG. 3A
, the intermediate transfer film
3
shifts in the width direction relative to a target object
9
, when they are near a position directly below the heating roller
5
for performing secondary transfer. As a result, an image-forming layer
10
to be transferred shifts or crinkles on the target object
9
, thereby bringing about transfer errors, such as a transfer positional shift
16
shown in
FIG. 3B
, or a transfer crinkle
17
shown in FIG.
3
C.
In the case of image formation performed by thermal transfer using the dot-on-dot method and an area gradation method, it is important to accurately position and set the intermediate transfer film
3
to have a proper orientation. If the set orientation of the intermediate transfer film
3
positionally shifts, it is difficult to accurately stack differently colored ink dots at a predetermined position, thereby bringing about a problem in that hardly any high quality image with predetermined color or gradation can be obtained.
Furthermore, when the setting method described with reference to
FIG. 2
is performed, key parts of image formation, such as the thermal head
1
and the platen roller
2
, which are disposed near the path of the ink ribbon
4
and the intermediate transfer film
3
, are contaminated directly or indirectly with foreign substances
18
and
19
(see
FIG. 1
, though they are exaggerated), such as dust and grease, which have stuck to the operator's hands, clothes, and so forth. As a result, an image transferred to a target object is caused by the foreign substances
18
and
19
to have image defects
20
and
21
in the finally transferred matter, as shown in
FIGS. 3D and 3E
.
In the apparatus shown in
FIG. 1
, the ink ribbon
4
is also set by a method as in the intermediate transfer film
3
. Consequently, also when the ink ribbon
4
is set, key parts of image formation in the apparatus are stained with foreign substances from operator's hands, clothes, and so forth, thereby bringing about image defects
20
and
21
in the finally transferred matter, as shown in
FIGS. 3D and 3E
.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming
Honma Nobuaki
Marugame Tomoyuki
Mita Tomoko
Toppan Printing Co. Ltd.
Tran Huan Huu
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