JP3320167B2 - Thermal printer paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a sheet feeding apparatus of Therma Help printer.

[0002]

2. Description of the Related Art There are two types of thermal printers: a thermal transfer recording type, in which a thermal head is heated from behind an ink film to transfer the ink of the ink film to recording paper to record an image; There is a heat-sensitive recording type in which an image is recorded by developing a color. In these thermal printers, the recording paper sent from a paper cassette is conveyed toward a recording position. At this recording position, a thermal head and a platen for receiving recording paper pressed by the thermal head are arranged.

In a thermal line printer, a recording paper is passed through a thermal head at a predetermined speed by a paper feeding device, and an image is recorded on the recording paper during the passage. Conventional paper feeders include a type in which recording paper is wound around the outer periphery of a large-diameter platen drum, and the recording paper is conveyed by rotating the platen drum. There is a type in which the recording paper is nipped and conveyed between the capstan roller and the pinch roller.

The latter capstan type has an advantage that the thermal line printer can be reduced in size because a platen roller having a small diameter can be used. However, when the end portion of the recording sheet is nipped by the capstan roller and the pinch roller, the position where the thermal head faces is the recording start position, so that a large margin is formed on the recording sheet.

To cope with this problem, Japanese Patent Laid-Open No.
As described in Japanese Patent No. 411961, a capstan roller is arranged so as to contact a platen roller at a position close to a thermal head using a platen roller having a large diameter, and a distance between the capstan roller and the thermal head. There is known a paper feeder in which the length is shortened.

[0006]

However, since the capstan roller rotates the platen roller indirectly and nips the recording paper between them to feed the paper, the capstan roller has a moderate size. Is used. Therefore, there is naturally a limit in reducing the margin by bringing the capstan roller close to the thermal head.

[0007] The present invention is intended to solve the above problems, and an object thereof is to provide a paper feeding mechanism of Therma pulp printer that allow thermal recording to the sheet feeding direction of the distal end portion of the recording paper.

[0008]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, during rotation of the platen roller,
The rotating shaft through which the heart is inserted is freely rotatable with respect to the platen roller.
And a pair of rotating shafts
A capstan roller is arranged, and a pair of pinch rollers are arranged to face each capstan roller, and the recording paper is conveyed by nipping both sides between them. Claim 2
In the described invention, the thermal line printer records an image line by line on the recording paper. According to the third aspect of the present invention, a pressing mechanism for pressing the pinch roller against the capstan roller is provided.

[0009]

Since the pinch roller and the thermal head are arranged in a straight line, the recording start position of the recording paper can be set near the paper end, and the margin becomes small.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS.
Uses a relatively hard rubber roller and is rotatably mounted on a chassis (not shown). Above the platen roller 2, a vertical thermal head 3 for performing thermal recording on the color thermosensitive recording paper 16 supported thereon is disposed. In the thermal head 3, a number of heating elements constituting a heating element 3 a are arranged in a line in the axial direction of the platen roller 2. Each heating element generates thermal energy according to the density of the pixel and thermally records an image on the color thermosensitive recording paper 16. The platen roller 2 is rotatably supported on a rotating shaft 4.

A capstan roller 5 having substantially the same diameter as the platen roller 2 so as to sandwich the platen roller 2.
6 is fixed to the rotating shaft 4 of the platen roller. The capstan rollers 5 and 6 are metal rollers having fine irregularities on the surface, and control the amount of paper feed of the color thermosensitive recording paper 16. When the capstan rollers 5 and 6 rotate, the inter-color thermal recording paper 16 is sent to the platen roller 2.
Follow it.

The pinch rollers 7 and 8 are located so as to face the capstan rollers 5 and 6 on both sides of the thermal head 3. The pinch rollers 7 and 8 are provided with respective arms 9a,
9b is rotatably mounted in a cantilever manner. The arms 9a and 9b are fixed to a rotating shaft 9d rotated by a motor. One arm 9b is urged counterclockwise by a coil spring 9c, and pinch rollers 7, 8 are pressed against capstan rollers 5, 6. These pinch rollers 7, 8 rotate following the capstan rollers 5, 6. These pinch rollers 7 and 8 are usually rubber rollers.

On both sides of the thermal head 3, ultraviolet lamps 10 and 11 for emitting ultraviolet light for light fixing are arranged, respectively. The ultraviolet lamp 10 has an emission peak of almost 4
A 20 nm rod-shaped yellow fixing is used, and the ultraviolet lamp 11 is used for magenta fixing having an emission peak of about 365 nm. Since these ultraviolet lamps 10 and 11 are formed with a reflection film except for the opening, ultraviolet rays are emitted in a fan shape. Here, in order to reduce the margin of the color thermal paper 16, it is preferable that the ultraviolet lamps 10 and 11 are located as close to the thermal head as possible.

On the left side of the thermal head 3, a paper discharge passage 15 and a retreat passage 20 formed by guide plates 13 and 14 are provided. At the junction of these passages, a path switch is provided, and when the color thermosensitive recording paper 16 is conveyed, the path switch 17 causes
It is guided to either the discharge port 15a or the evacuation passage 20. The paper discharge roller pair 18 is provided in the paper discharge passage 15, rotates at the same peripheral speed as the capstan roller 5, and
And send it to the tray 19 through the discharge port 15a.

On the right side of the thermal head 3, there is provided a paper feed passage 25 comprising guide plates 23 and 24. In a cassette chamber connected to the paper feed passage 25, a paper feed cassette 26 in which color thermal recording papers 16 are stacked and stored is set. A paper supply roller 27 is provided above the paper supply cassette 26, and pushes out the first color thermal recording paper 16 and sends it to an entrance 25 a of a paper supply passage 25.

A bottom plate 26a is mounted in the paper feed cassette 26. When the leading end is pushed up by the lift lever 30, the color thermal recording paper 16 at the top is
Is brought into contact with the paper feed roller 27.

FIG. 8 shows an example of a color thermosensitive recording paper. On a support 30, a cyan thermosensitive coloring layer 31,
A magenta thermosensitive coloring layer 32, a yellow thermosensitive coloring layer 33, and a protective layer 34 are sequentially provided. These thermosensitive coloring layers 31 to 33 are layered from the surface in the order of thermal recording. The cyan thermosensitive coloring layer 31 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops cyan when heated.

As the magenta thermosensitive coloring layer 33, a diazonium salt compound having a maximum absorption wavelength of about 365 nm;
It contains a coupler that reacts with heat and develops magenta. When the magenta thermosensitive coloring layer 56 is irradiated with an ultraviolet ray near 365 nm after the magenta image is thermally recorded by the thermal head 3, the diazonium salt compound is photodecomposed and the coloring ability is lost.

The yellow thermosensitive coloring layer 33 contains a diazonium salt compound having a maximum absorption wavelength of about 420 nm and a coupler which reacts with the diazonium salt compound to develop yellow color. The yellow thermosensitive coloring layer 33 is fixed by light when irradiated with near ultraviolet rays near 420 nm, and loses its coloring ability.

The operation of the thermal printer configured as described above will be described. When the print start switch is turned on, the paper feed roller 27 rotates clockwise. At the same time, a solenoid (not shown) operates to rotate the lift lever 30 counterclockwise. This lift lever 3
0 raises the front end side of the bottom plate 26a and makes the first color thermosensitive recording paper 16 contact the paper feed roller 27.

As shown in FIG. 5, the paper feed roller 27 pushes out the first color thermosensitive recording paper 16 toward the paper feed passage 25. At this time, the path switching 17 is performed so that the color thermosensitive recording paper 16 is guided to the escape passage 20.

The capstan rollers 5 and 6 start rotating counterclockwise simultaneously with the sheet feeding roller 27. When the capstan rollers 5 and 6 rotate, the pinch rollers 7 and 8 in contact therewith also follow and rotate clockwise. Color thermosensitive recording paper 1 entering paper feed passage 25 from paper feed port 23a
6 is a pinch roller 7, 8 and a capstan roller 5, 6
Nipped between.

The leading end 16 of the color thermosensitive recording paper 16
At the timing when a is nipped between the pressing rollers 7, 8 and the capstan rollers 5, 6, the lift lever 30 is lowered and the color thermosensitive recording paper 16 being conveyed is fed to the paper feeding roller 27.
Move away from

When the leading end 16a of the color thermosensitive recording paper 16 is nipped between the pinch rollers 7, 8 and the capstan rollers 5, 6, thermal recording by the thermal head 3 is started. At the time when this thermal recording is started, the thermal head is located on the center line of the capstan rollers 5, 6 and the nip rollers 7, 8, so that the recording start position of the color thermal recording paper 16 is near the leading end and the margin is considerably large. Become smaller.

The thermosensitive recording paper 16 is conveyed toward the retreat passage 20 while nipping the color thermosensitive recording paper between the pinch rollers 7 and 8 by the rotation of the capstan rollers 5 and 6. During this conveyance, each heating element of the thermal head 3 is heated to a temperature in consideration of the coloring characteristics of the yellow thermosensitive coloring layer 31, and the yellow thermosensitive coloring layer 31 is thermally recorded one line at a time. The ultraviolet lamp 10 is turned on during the thermal recording of the yellow image, and the recorded yellow thermosensitive coloring layer 33 is fixed.

As shown in FIG. 6, the color thermosensitive recording paper 16
When the rear end portion 16b reaches a position immediately below the thermal head 3, the thermal recording of the yellow image ends, and the rotation of the pinch rollers 7, 8 and the capstan rollers 5, 6 is temporarily stopped.

Next, the capstan rollers 5, 6 rotate clockwise, and the pinch rollers 7, 8 rotate counterclockwise. As a result, the color thermosensitive recording material 16 is returned toward the paper feed cassette 26, and as shown in FIG.
b enters the paper feed cassette 26. While the color thermosensitive recording paper 16 is returned toward the paper feed cassette 26, the thermal head 16 thermally records a magenta image line by line on the magenta thermosensitive coloring layer 32. With this,
When the ultraviolet lamp 11 is turned on, almost three
Magenta thermosensitive coloring layer 3 thermally recorded with 65 nm ultraviolet rays
2 is fixed.

Again, the capstan rollers 5, 6 rotate clockwise, and thermal recording of the cyan image starts from the state shown in FIG. In the thermal recording of the cyan image, since the path switching 17 operates to open the paper discharge passage, the color thermosensitive recording paper 16 enters the paper discharge passage 15 with the leading end 16a at the head. Then, the sheet is nipped by a pair of sheet discharge rollers 18 and discharged to a tray 19.

In the embodiment shown in FIG. 9, a horizontal thermal head is used instead of a vertical thermal head. In this embodiment, the two ultraviolet lamps 10 and 11 are connected to the evacuation passage 50 because the ultraviolet lamp on the paper feed side is in the way.
And near the entrance of the paper discharge passage 45. The printing procedure is the same as that of the embodiment shown in FIGS. 1 to 7, and the same members are denoted by the same reference numerals.

Although the above embodiment is directed to a thermal recording type color thermal printer, the present invention can also be applied to a thermal transfer recording type color thermal printer using an ink film. This thermal transfer recording type color thermal printer does not require an ultraviolet lamp for fixing, and thus can theoretically eliminate printing margins. Further, the present invention can be used for monochrome thermal printers in addition to color printers.

[0031]

As described above in detail, according to the present invention, the rotating shaft through which the rotation center of the platen roller is inserted is pressed.
It is provided so that it can rotate with respect to the Latin roller.
A pair of capstan rollers that rotate with the rotating shaft
And location, provided pinch rollers on both sides of the thermal head so as to face the respective capstan roller, it is so arranged to convey the clamped on both sides of the recording paper, and a wide recording area of the recording paper, extreme margins Can be made smaller. Further, the recording paper is conveyed by driving the capstan roller, so that the platen roller can be formed of a hard material with little deformation. Thereby, the thermal head and the recording paper can be effectively brought into close contact with each other, and the printing quality is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a paper feeding device of the present invention.

FIG. 2 is a side view of the paper feeding device shown in FIG.

FIG. 3 is a front view of the paper feeding device shown in FIG. 1;

FIG. 4 is a schematic diagram of a printer using the paper feeding device of the present invention.

FIG. 5 is a schematic view similar to FIG. 4, showing a paper feeding state.

FIG. 6 is a schematic diagram illustrating a state in which recording of a yellow image has been completed.

FIG. 7 is a schematic diagram illustrating a state where recording of a cyan image is started.

FIG. 8 is an explanatory diagram showing a layer structure of a color thermosensitive recording paper.

FIG. 9 is an explanatory view showing another embodiment of the present invention.

[Explanation of symbols]

 2 Platen Roller 3 Thermal Head 3a Heating Element 4 Rotating Axis 5,6 Capstan Roller 7,8 Pinch Roller 10,11 Ultraviolet Lamp 15,45 Paper Ejection Path 16 Color Thermal Recording Paper 25,50 Evacuation Path 25 Feeding Path 26 Feeding Paper cassette 27 Paper feed roller

Claims (3)

(57) [Claims] 1. A thermal printer for recording an image on recording paper supported by a platen roller by using a thermal head extending in an axial direction of a platen roller, wherein a rotation shaft passing through a rotation center of the platen roller is connected to the thermal shaft.
Provided so that it can rotate freely with respect to the platen roller.
On both sides of the platen roller, a pair of capstan rollers that rotate together with the rotating shaft are arranged, and a pair of pinch rollers are arranged opposite to each capstan roller, and both sides of the recording paper are nipped between them. A paper feed device characterized in that the paper is transported. 2. The paper feeder according to claim 1, wherein the thermal printer is a thermal line printer that records an image line by line on the recording paper. 3. The paper feeder according to claim 1, further comprising a pressing mechanism for pressing said pinch roller against a capstan roller.