Typewriting machines – Typing by other than type-face or type-die – Thermal
Reexamination Certificate
1999-06-21
2001-04-17
Colilla, Daniel J. (Department: 2854)
Typewriting machines
Typing by other than type-face or type-die
Thermal
C400S088000, C347S197000
Reexamination Certificate
active
06217240
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a miniature printer used in a cash register or the like. Particularly the present invention relates to a device for controlling the head pressure in a miniature printer, in which a pair of hinge parts with an elongate shaft retaining slot in each of them are formed on the bottom of a head frame so as for a printer head to be closely contacted to the surface of a platen roller. Elastic members are fixed to the head frame, and a supporting bracket is installed in rear of the head frame across the elastic members so as to be pivoted together with the head frame, so that a stable running of the printer paper is ensured, and the printing state is made clear.
2. Description of the Prior Art
In the generally known miniature printers used in a cash register or the like, as shown in
FIG. 1
, a printer head
10
is integrally formed with a head frame
12
, and at the rear of the head frame
12
, there is installed a supporting bracket
16
to be elastically supported by springs, so that the head frame
12
and the supporting bracket
16
would be elastically supported. A pair of hinge parts
18
are formed on the bottom of the head frame
12
and the supporting bracket
16
.
Further, a shaft
22
is formed upon a base plate
20
, and a locking piece
28
is pivotally installed on the rear face of the supporting bracket
16
. When the lower end of the locking piece
28
contacts a projected step
24
, the printer head
10
contacts a platen roller
26
.
In the above described printer, the head frame
12
together with the printer head
10
is pivoted forward by a certain angle to be contacted to the platen roller
26
(the printing paper passes by the roller
26
), thereby carrying out the printing. In this case, springs
14
are installed to the rear face of the head frame
12
, and thus the supporting bracket
16
pivots together with the head frame
12
. Thus if the locking piece
28
is turned downward, the supporting bracket
16
pivots around the shaft
22
. Under this condition, the head frame
12
together with the printer head
10
pivots forward to make the printer head
10
contact the platen roller
26
, and therefore, a printing operation is carried out on the paper which passes through the platen roller
26
.
However, in the above described printer, the head frame
12
is pivoted in accordance with the pivoting of the locking piece
28
. Therefore, when a contacting force acts on the platen roller
26
, a part of the printer head
10
closely contacts with the platen roller
26
owing to the incoming paper, while gaps remain at either of the end portions of the printer head
10
. Due to these gaps between the printer head
10
and the platen roller
26
, a clear printing cannot be realized.
A printer related to this technique is disclosed in Japanese Patent Application Laid-open No. Hei-7-25084.
This printer is illustrated in FIG.
2
. As shown in this drawing, springs
52
are secured to the rear face of a head frame
50
, and a printer head
54
is supported by the springs
52
. A platen rubber member
64
is supported by a shaft
58
which is secured on a base frame
56
. Inside the platen rubber member
64
, there are installed a main platen supporting member
62
and an auxiliary platen supporting member
60
, so that the platen rubber member
64
can be closely contacted to the shaft
58
. Further, the platen supporting members
60
and
62
respectively have contacting parts
66
′ and
66
. A printing paper roll
68
is disposed on a side of the base frame
56
.
In the above described printer, when the printer head
54
, which is elastically supported by the springs
52
of the head frame
50
, is contacted to the platen rubber member
64
, the platen rubber member
64
contacts both of the contacting parts
66
′ and
66
, and therefore, a stable position is maintained all the time. The contacting parts
66
and
66
′ which are formed respectively within the platen supporting members
60
and
62
contact with the shaft
58
so as to be rotated together with the shaft
58
. Accordingly the printer head
54
stably contacts with the platen rubber member
64
, thereby carrying out a printing on the paper of the paper roll
68
.
However, the printer head
54
which closely contacts with the platen rubber member
64
always contacts with a side of the base frame
56
. Therefore, if the platen supporting members
60
and
62
are damaged, then a part of the printer head
54
contacts with the platen rubber member
64
, while a gap is formed between the other ends of the printer head
54
and the platen rubber member
64
. At this situation, the adjustment of the gap is very difficult, and therefore, the printing quality is aggravated, or the paper is ejected in a skew posture, or the paper may be jammed.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the above described disadvantages of the conventional techniques.
Therefore it is an object of the present invention to provide a device for controlling the head pressure in a miniature printer, in which a gap between a printer head and a platen roller is compensated by elongate slots of hinge parts, so that the contact between the platen roller and the printer head is improved, that a clear printing can be maintained, that a paper jam can be prevented to avoid the damage of the head, and that a running stability can be ensured to extend the life expectancy of the printer.
In achieving the above object, the device for controlling a head pressure in a miniature printer according to the present invention includes: a printer head installed on front of a head frame; a platen roller for carrying a printing paper in contact with the printer head; a supporting bracket connected through elastic members to the rear face of the head frame; a frame pivoting part with the head frame and the supporting bracket pivotally connected thereto; a frame supporting part installed on the head frame, for preventing a biasing of the frame pivoting part; a frame degapping part formed on the frame pivoting part, for making both ends of the head frame degapped; and a locking piece for preventing the pivoting of the supporting bracket back and forth.
In another aspect of the present invention, the device for controlling a head pressure in a miniature printer according to the present invention includes: a printer head installed on front of a head frame; a platen roller for carrying a printing paper in contact with the printer head; a supporting bracket connected through elastic members to the rear face of the head frame; a frame pivoting part with the head frame and the supporting bracket pivotally connected thereto; a frame supporting part installed on the head frame, for preventing a biasing of the frame pivoting part; a frame degapping part formed on the frame pivoting part, for making both ends of the head frame degapped; a locking piece for preventing the pivoting of the supporting bracket back and forth; a frame connecting part for connecting the supporting bracket to the head frame; and a bracket pivoting part for allowing the supporting bracket to move back and forth.
REFERENCES:
patent: 4560292 (1985-12-01), Takahasi
patent: 5040461 (1991-08-01), Van-Ocker
patent: 5148187 (1992-09-01), Ono et al.
patent: 5157415 (1992-10-01), Seyasu
patent: 5160205 (1992-11-01), Mistyurik
patent: 5309176 (1994-05-01), Faes et al.
patent: 5594487 (1997-01-01), Nuita et al.
patent: 5886725 (1999-03-01), Miyadera et al.
patent: 7-25084 (1995-01-01), None
patent: 7-246751 (1995-09-01), None
Colilla Daniel J.
Renner , Otto, Boisselle & Sklar, LLP
Samsung Electro-Mechanics Co. Ltd.
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