Incremental printing of symbolic information – Thermal marking apparatus or processes – Preheating
Reexamination Certificate
2000-06-22
2001-04-17
Tran, Huan (Department: 2861)
Incremental printing of symbolic information
Thermal marking apparatus or processes
Preheating
Reexamination Certificate
active
06219078
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printer with sheet preheating in which a thin film heat transfer toner ribbon material is heat-transferred onto a recording sheet by a thermal head or a laser.
2. Description of the Related Art
Conventionally, for example, as shown in
FIG. 8
, a printer
1
using a line thermal head includes as main structural members: a thermal head
3
; a platen roller
5
which opposes a resistance heat generating body
3
a
of the thermal head
3
; a toner ribbon
7
which is disposed between the thermal head
3
and the platen roller
5
and which is supplied from a conveying side
7
a
and is taken up onto a winding side
7
b
; a guide roller
9
which guides the toner ribbon
7
; a pinch roller
11
and a capstan roller
13
which are provided at the downstream side of the thermal head
3
in the feeding direction of a recording sheet; and a back-up roller
15
which abuts the pinch roller
11
.
As shown in
FIGS. 9A through 9C
, in order to effect heat recording onto a recording sheet in the printer
1
structured as described above, firstly, a heat adhesive recording sheet (a recording sheet)
17
which has a heat adhesive layer
17
a
on the surface is fed (see FIG.
9
A). The toner ribbon
7
is superposed on the recording sheet
17
, and the toner ribbon
7
and the recording sheet
17
are inserted between the thermal head
3
and the platen roller
5
. Next, when a portion of the resistance heat generating body dots corresponding to an image to be printed is selectively heated, adhesive strength of the surface of the recording sheet is increased and toner adheres onto the recording sheet
17
from the toner ribbon
7
(see FIG.
9
B). Subsequently, when the toner ribbon
7
separates from the recording sheet
17
while the recording sheet
17
is conveyed, only the toner portion t adhered to the surface of the recording sheet is remained and fixed onto the recording sheet
17
(see FIG.
9
C). In this way, the image information is recorded onto an image receiving surface of the recording sheet
17
.
However, in the aforementioned conventional heat transfer type printer
1
, a predetermined amount of thermal energy is supplied to the toner ribbon
7
from the thermal head or laser, and the toner and the surface of the recording sheet are heated for transfer. Accordingly, the heat adhesiveness of the surface of the recording sheet is changed by environment to be used (in particular, temperature) and sensitivity (the degree of amount of transfer relative to the amount of heat to be supplied) varies. Thus, there is a drawback in that recording densities become different.
Namely, in the recording sheet
17
shown in
FIG. 10A
, a surface polymer which forms the heat adhesive layer
17
a
tends to harden at low temperature. As a result, the adhesive strength of the recording sheet
17
lowers in low-temperature environment. On the other hand, if the heat adhesive layer
17
a
is heated in advance, the adhesive strength of the recording sheet remains high even if the recording takes place several hours later.
Therefore, as shown in
FIG. 10B
, when a plurality of colors are superposed and recorded onto the recording sheet
17
, a first color
19
a
is directly recorded onto the surface of the recording sheet
17
and a second color
19
b
is superposed and recorded onto the toner of a first color
19
which has been recorded onto the recording sheet
17
. In this case, the head adhesive strength of the second color
19
b
, which is heated again, is higher than that of the first color
19
a
. As a result, the sensitivities become different and a drawback arises in that the recording densities become different.
SUMMARY OF THE INVENTION
The present invention was developed in light of the above circumstances, and the object thereof is to provide a printer with sheet preheating in which sensitivity does not vary due to the difference in environment and difference in the order of transfer.
In order to achieve the above-described object, a first aspect of the present invention is a printer with sheet preheating in which toner applied to a toner ribbon is heat-transferred onto a heat adhesive recording sheet, wherein: heating means which heats the recording sheet at a temperature within a range of predetermined temperatures before the heat transfer is provided.
It is preferable that said heating means is a pinch roller in which a heater is built.
Further, said heating means may be a heat roller provided at the upstream side of said heat transfer means in the feeding direction of the recording sheet.
Moreover, said heating means can be a radiation heater provided at the upstream side of said heat transfer means in the feeding direction of the recording sheet.
Furthermore, it is preferable that the range of predetermined temperatures is from 70° C. to 120° C.
Because the above-structured printer includes the heating means which heats the recording sheet at a temperature before the heat transfer, the adhesiveness of the heat adhesive recording sheet can be substantially constant regardless of the environment of circumferential temperature and the like.
In the printer with sheet preheating in which the pinch roller serves as heating means, it is not necessary to provide a new member independently, such that the number of parts of the device does not increase.
Further, in the printer with sheet preheating in which the heat roller provided at the upstream side of the heat transfer means in the feeding direction of the recording sheet serves as heating means, there is no need to convey the recording sheet reciprocally for heating.
Moreover, in the printer with sheet preheating in which the radiation heater provided at the upstream side of the heat transfer means at the feeding direction of the recording sheet serves as heating means, because the recording sheet is heated by radiation, the contact between the heating means and the recording sheet is prevented.
Furthermore, in the printer with sheet preheating which uses the heating means for heating the surface of the recording sheet at the side opposite the transferred surface thereof, the adhesion of toner to the heating means, which occurs in a case in which the heating means contacts and heats the transferred surface of the recording sheet, is prevented.
Still further, in the printer with sheet preheating in which the heat source and the heat roller for transferring the toner on the recording sheet to the main paper are used as heating means, there is no need to provide separate heating means.
REFERENCES:
patent: 5553951 (1996-09-01), Simpson et al.
patent: 2-538 (1990-01-01), None
patent: 2-88253 (1990-03-01), None
patent: 3-126561 (1991-05-01), None
patent: 7-290735 (1995-11-01), None
patent: 8-025677 (1996-01-01), None
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Tran Huan
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