JPH07115514B2 - Media feeding device for printing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium feeding mechanism for a single-cut medium in a printing device.

[Conventional technology]

2. Description of the Related Art Conventionally, as a method of feeding a single-cut medium in a printer or a printer of a typewriter, there is known a method of nipping and feeding by a cylindrical platen made of rubber on the surface and a pinch roller pressed against the platen.

A conventional technique for implementing the above method will be described with reference to the side sectional view of FIG.

In the figure, 1 is a cylindrical platen whose surface is covered with rubber, and 2 is a paper sheet which is formed so as to surround the platen 1 from the lower side to the vicinity of the printing position. The single-cut medium 3 can be smoothly fed. Is formed.

4a and 4b are pinch rollers, which are in pressure contact with the platen 1 above.
When the platen 1 is pressed against the platen 1, the single-cut medium 3 is nipped and sequentially fed.

Reference numeral 5 denotes a presser spring, which presses the pinch rollers 4a and 4b against the platen 1 via the pinch roller holder 6.

A bail roller 7 is movably attached between a position in contact with the platen 1 and a position separated from the platen 1. Reference numeral 8 is a print head, and 9 is a base.

According to the above configuration, the end 3a of the single-cut medium 3 inserted from the open end of the paper sheet 2 behind the platen 1
Is set and set at the pressure contact portion between the platen 1 and the pinch rollers 4a and 4b. Therefore, when the platen 1 rotates in the feeding direction indicated by the arrow, the single-cut sheet medium 3 is sandwiched between the platen 1 and the pinch rollers 4a and 4b, guided by the paper sheet 2 and passes through the print position of the print head 8, and then the bail roller. The platen 1 is pressed by 7 and positioned.

After that, printing and line feed are repeated by the printing head 8, and the single-cut sheet medium 3 is sequentially fed while being sandwiched by the platen 1 and the pinch rollers 4a and 4b.

[Problems to be solved by the invention]

According to the conventional technique described above, as shown in FIG. 6, the angle θ formed by the line connecting the axis of the platen 1 and the axis of the pinch roller 4a and the inserting direction of the cut medium 3 is θ> 90 °. In the case of a thin single-cut medium, the medium is slack toward the paper chute side because the medium is weak, and if the medium is conveyed as it is, wrinkles may occur or pressure-sensitive copy paper may be generated if the pressure force of the pressure spring 5 is strong. There is a problem that there is a trace of Laura.

Therefore, when the pressing force of the pressurizing spring 5 is reduced, in the case of a thick single-cut sheet medium, since the bending rigidity of the medium when guided by the paper sheet 2 is large, the single-cut sheet medium 3 bends with the platen 1. There is a problem with slipping and poor feeding.

Therefore, as a means for solving these problems, by setting θ << 90 ° as shown in the side sectional view of FIG. Since the platen 1 and the pinch rollers 4a and 4b do not have a wrinkle between them and the thick single-cut sheet medium 3 has a small bending rigidity due to the change of direction after the sheet is sandwiched, resulting in less slippage.

However, when a thick cut medium 3 is inserted, the tip 3a of the cut medium 3 does not reach the pressure contact portion between the platen 1 and the pinch rollers 4a, 4b due to the bending rigidity of the cut medium, and the tip end of the cut medium 3 is inserted. Since 3a must be pushed into the pressure contact portion by hand, there is a problem that the auto-loading of the single-cut medium 3 cannot be performed and the operability is poor.

Further, as shown in FIG. 6, another pinch roller 4b is required in the vicinity of the print head 8 in order to stably feed the medium to the vicinity of the end thereof, and there is a problem that the parts structure is complicated.

[Means for solving problems]

In a medium feeding device of a printing device, which comprises a cylindrical platen connected to a drive control means, a pinch roller pressed against the platen, and an arcuate paper sheet for guiding a single-cut medium to a printing position, a platen is provided. Swing arms are attached to both sides of the shaft, a rotary shaft having a pinch roller is attached to this swing arm, and this pinch roller is pressed against the platen so that the pinch roller can be moved along the platen periphery according to the movement of the swing arm. A feature is that stoppers are provided at the respective positions so that the arm can reciprocate between the feeding position and the printing position of the single-cut medium.

[Action]

According to the above configuration, the swing arm can be rotated with the rotation of the platen to move the pinch roller along the periphery of the platen, and when setting the single-cut medium, θ> 90 °. The vicinity of the pressure contact area between the platen and the pinch roller is opened to facilitate the feeding of the leading edge of the single-cut medium into the pressure contact area.After the feeding, the pinch roller moves along the platen peripheral surface as the platen rotates. Therefore, θ can be set to 90 °, so that the single-cut medium can be curled and wrinkles do not occur even on thin paper, and even thick paper can be fed without slipping.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a disassembled perspective view, and Fig. 2 is a sectional view taken along the line I-I in Fig. 1. In the figure, 1 is a platen, 1a is a platen shaft of the platen 1, 2 is a paper sheet, 3 is a single-cut medium. , 7
Is a bail roller, and 8 is a print head, which are the same as those in the prior art.

Reference numeral 10 denotes a pair of pinch rollers, which are supported by a rotating shaft 10a at predetermined intervals.

11 is a pair of left and right swing arms, and has a shaft hole 11a at one end.
Is provided so that the platen shaft 1a can be passed therethrough.

11b is an elongated hole provided in the middle, through which the rotary shaft 10a is passed. Reference numeral 11c is a locking tongue, and 11d is a locking portion.

Reference numeral 12 denotes a holder having a bearing recess 12a, and the locking portion 11d
It is slidably fitted to and the bearing recess 12a is aligned with the elongated hole 11b.

Reference numeral 13 denotes a bottom plate 12b of the holder 12 and a locking tongue piece 1 of the swing arm 11.
It is a compression spring installed between 1c and compression.

Therefore, on both sides of the platen shaft 1a, the shaft holes of the swing arm 11
11a is fitted and rotatably integrated, and further the rotary shaft 10a is fitted into the long hole 11b of the swing arm 11, and the rotary shaft 10a is pressed by the compression spring 13 through the bearing recess 12a of the holder 12. The pinch roller 10 is supported and pressure-bonded to the platen 1 through the window 2a of the paper sheet 2.

The platen shaft 1a of the platen 1 thus configured is attached to the chassis 14
The paper bush 2 is rotatably supported by the bearing bush 15 through the bearing hole 14a, and one end of the paper shout 2 is also fixed to the chassis 14.

Reference numerals 16 and 17 denote stoppers, which are set so that the swing arm can be reciprocated between the feeding position of the single-cut sheet medium and the front position of the printing position.

The operation of this embodiment having the above structure will be described with reference to the sectional views of FIGS. 3 and 4. FIG. 3 shows a state in which the single-cut medium 3 is set, and FIG. 4 shows a state immediately after the single-cut medium 3 is fed. First, from the rear of the platen 1 to the paper sheet 2, the single-cut medium 3 is shown. Insert, the single-cut medium 3 is θ
Since the angle is> 90 °, the tip 3a is positioned by abutting the pressure contact portion between the platen 1 and the pinch roller 10.

In this state, when the platen 1 is rotated in the direction of the arrow in FIG. 3 by the drive control means (not shown), the leading edge 3a of the single-cut sheet medium 3 is pinched by the platen 1 and the pinch roller 10 and, at the same time, the swing arm around the platen shaft 1a. 11 rotates in the direction of the arrow, and the pinch roller 10 also holds the cut sheet medium 3 while holding the stopper 16
From to Stuppa 17. In this state, the pinch roller 10 is rotated around the rotary shaft 10a in cooperation with the rotation of the platen 1, the cut sheet medium 3 is fed, and is pressed by the bail roller 7 to be positioned at a predetermined position.

In this state, printing and line feed are repeated, and each time the platen 1 rotates, the pinch roller 10 continues to rotate at this position, and when printing is completed, the cut sheet medium 3 is ejected.

Next, when the single-cut medium 3 is set again, if a command for setting the single-cut medium 3 is issued by pressing a switch, for example,
The platen 1 is rotated in the direction of the arrow in FIG. 4 by the platen drive control means. Along with the rotation, the left and right swing arms 11 rotate around the platen shaft 1a in the direction of the arrow to come into contact with the stopper 16 and stop, returning to the initial state.

Next, a second embodiment will be described with reference to the disassembled partial perspective view of FIG.

This embodiment has a structure in which gears 18 and 19 are attached to and meshed with the platen shaft 1a and the rotary shaft 10a, respectively. In the first embodiment, the force for moving the swing arm 11 is the platen 1
In this embodiment, the driving force of the gear 18 is transmitted to the gear 19 to rotate the rotary shaft 10a, and the swinging motion of the swing arm 11 is further ensured.

〔The invention's effect〕

According to the present invention described above, the swing arm attached to the platen shaft is pivotally supported by the rotary shaft attached with the pinch roller to bring the pinch roller into contact with the platen, and the swing arm is rotated along with the rotation of the platen. By moving the pinch roller around the platen, the angle between the line connecting the platen and the center of the pinch roller and the insertion direction of the cut medium θ> 90 ° Therefore, the vicinity of the pressure contact portion between the platen and the pinch roller is opened, the leading end of the single-cut medium is easily fed into the pressure contact portion, and auto loading is also possible. And
After feeding, the pinch roller moves along the platen as the platen rotates and becomes θ << 90 °, so the single-cut medium curls and does not cause wrinkles even on thin paper and on thick paper. It will be possible to deliver without slipping.

Further, since the pinch roller moves to the vicinity of the print head, the distance l from the pressure contact portion of the pinch roller and platen to the printing can be shortened, and stable medium feeding can be performed by the platen, pinch roller and bail roller. In addition, there is the effect that the single-cut medium does not float and the print quality can be improved, and the second pinch roller, which has been conventionally required, is not required.

[Brief description of drawings]

FIG. 1 is a disassembled perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II of FIG. 1, and FIG. 3 is a sectional view taken along the line II of FIG. 1 when a single-cut medium is inserted. FIG. 4 is a sectional view taken along the line II of FIG. 1 in a state in which the single-cut sheet medium is discharged after printing is completed, FIG. 5 is a partially exploded perspective view of the second embodiment, and FIG. 6 is the side of the first conventional example. Cross section,
FIG. 7 is a side sectional view of the second conventional example. 1 ... Platen, 1a ... Platen axis, 2 ... Paper sheet, 3 ... Single-cut medium, 8 ... Printing head, 10 ... Pinch roller, 10a ... Rotation axis, 11 ... Swing arm

Claims (2)

[Claims] 1. A medium feeding device for a printing apparatus comprising a cylindrical platen connected to drive control means, a pinch roller pressed against the platen, and an arcuate paper chute for guiding a single-cut medium to a printing position. In the device, swing arms are attached to both sides of the platen shaft, a rotary shaft having a pinch roller is attached to this swing arm, this pinch roller is pressed against the platen, and the pinch roller can be moved along the platen periphery according to the movement of the swing arm. A medium feeding device for a printing device, wherein stoppers are provided at respective positions so that the swing arm can reciprocate between a feeding position of a single-cut medium and a front position of a printing position. 2. An intermediate feeding device for a printing apparatus according to claim 1, wherein gears are attached to the platen shaft and the rotary shaft, respectively, and these gears are meshed with each other.