JP2744161B2 - Printer clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp device for a printer for fixing the leading end of a recording paper to an outer periphery of a platen drum.

[0002]

2. Description of the Related Art In general, a gate-shaped clamp arm is used as a clamp device of a printer, and the leading end of a recording paper is pressed against the outer periphery of a platen drum and fixed by this pressing portion. However, since the platen drum is made of rubber, the portion is deformed when the pressing by the pressing portion takes a long time. For this reason, guide pins for regulating, for example, the movement direction of the clamp arm only in the radial direction of the platen drum are implanted on the side surface of the platen drum so that the position where the platen drum is pressed is constant.

[0003]

However, as described above, since the guide pins are provided on the side surfaces of the platen drum, there is a disadvantage that the cost of the clamping device is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a clamp device for a printer which can fix the leading end of a recording paper at a fixed position on a platen drum at low cost.

[0005]

According to the present invention, at least a part of a platen shaft has a substantially D-shaped cross-section, and a long hole of a clamp arm inserted through the platen shaft is provided. A narrow opening that is engaged with the narrowest portion of the D-shaped cross section so that the relative position between the clamp arm and the platen drum is constant when the clamp arm is set at the clamp position; The platen drum has a wide opening having an inner diameter larger than the diameter of the platen shaft so that the platen drum is rotated independently of the clamp arm when set at the sheet discharge position.

[0006]

1 to 4, a plurality of sheet-like color thermosensitive recording materials 10 are stacked in a cassette 11, and the uppermost one is a paper feed roller 12;
And is sent to the paper feed passage 13. The paper feed path 13 is provided with a pair of transport rollers 14 for feeding the color thermosensitive recording material 10 sent from the cassette 11 toward the platen drum 15. The platen drum 15 is driven to rotate by a stepping motor 17 via a platen shaft 16.

The clamp arm 18 is substantially gate-shaped, and its pressing portion 18a presses and fixes the front end 10a of the color thermosensitive recording material 10 to the outer peripheral surface 15a of the platen drum 15. Also, the legs 18 of the clamp arm 18
b, a slot 19 is formed in the platen shaft 1.
6 passes. As shown in FIG. 2A, the platen shaft 16 has a D-shaped cross section.

The elongated hole 19 is formed by two openings 19a and 19b having widths d ₁ and d ₂ . The width d ₁ is smaller than the diameter 2r of the platen shaft 16, the width d ₂ of the other is wider than the diameter 2r of the platen shaft 16. FIG.
As shown in (A), when the platen shaft 16 is in the opening 19a, the platen arm 18 is
6 and both rotate integrally. FIG. 2 (B),
As shown in (C), when the platen shaft 16 is in the opening 19b, the platen shaft 16 and the platen arm 1
8 can rotate relatively. Also, the clamp arm 18 can be moved in the radial direction of the platen drum 15 only when the longitudinal direction of the elongated hole 19 is parallel to the plane portion 16a of the platen shaft 16, so that the clamp arm 18 is pressed by the pressing portion 18a during clamping. The portion of the outer peripheral surface 15a becomes constant. A spring 20 is stretched between the platen shaft 16 and the leg 18b via two pins to urge the clamp arm 18 toward the clamp position.

A pair of stop portions 18c are formed at corners of the pressing portion 18a and the leg portions 18b. When the clamp arm 18 is set at the sheet feeding position (see FIG. 3), the stop portion 18c receives the distal end portion 10a so as not to pass between the pressing portion 18a and the platen drum 15. When the clamp arm 18 is set at the paper discharge position (see FIG. 4), the tip of the stop portion 18c and the outer peripheral surface 15a of the platen drum 15 are
Is sufficient, the color thermosensitive recording material 10 can pass through between the outer peripheral surface 15a and the pressing portion 18a, and the forward rotation discharge is enabled.

A bent portion 21 is formed on the leg portion 18b, and the clamp arm 18 is pressed from the clamp position to the sheet feeding position and the discharge position by pressing the bent portion 21 of the leg portion 18b on the side of the platen drum 15. Paper feed lever 2 displaced to paper position
3. A paper discharge lever 24 is provided rotatably. At this clamp position, as shown in FIG.
The platen shaft 16 is inserted into the back of the opening 19a, and is guided by the flat portion 16a of the platen shaft 16 at the sheet feeding position.
It slides in the opening 19a. At the sheet discharge position, as shown in FIGS.
Is in the opening 19b. The paper feed lever 23,
The discharge lever 24 is driven by solenoids 25 and 26, respectively, and is retracted to the outside of the rotation locus of the bent portion 21 except during paper supply and paper discharge. The platen drum 15 has a pair of grooves 15b into which the stop portions 18c enter during clamping.

On the outer periphery of the platen drum 15, a thermal head 2 is located at a thermal recording position of the color thermal recording material 10.
7, a magenta optical fixing device 28 is disposed at a position downstream of the thermal head 27, and a yellow optical fixing device 29 is further disposed downstream thereof. Thermal head 27
Has a large number of heating elements arranged in a line in the main scanning direction, and each heating element generates heat energy according to the density of a pixel. The magenta light fixing device 28 includes an ultraviolet lamp 31 having a light emission peak of approximately 365 nm and a reflector 32, and the yellow light fixing device 29 has a light emission peak of approximately 4 nm.
20 nm rod-shaped UV lamp 33 and reflector 3
4 It should be noted that one ultraviolet lamp that emits ultraviolet light in the wavelength range of 365 to 420 nm and a filter that can be put in and out in front of the lamp are used.
The kind of ultraviolet rays may be selectively extracted. This optical fixing device is arranged at the position of the magenta optical fixing device 28.

A stopper 36 is provided between the thermal head 27 and the magenta optical fixing device 28. The stopper 36 is used to release the fixing of the color thermosensitive recording material 10 so that the clamp arm 18 is positioned at the paper discharge position (see FIG. 4).
After being moved to the clamp arm 18, the clamp arm 18 is prevented from rotating together with the platen drum 15.
Take it.

Between the magenta light fixing device 28 and the yellow light fixing device 29, a color thermosensitive recording material 1 in which all the heat recording is completed with the outer wall surface of the reflector 34 as a part thereof.
A paper discharge path 37 for discharging paper 0 is provided, and a transport roller pair 39 for nipping the color thermosensitive recording material 10 and transporting the paper toward a paper discharge tray 38 is provided at the back of the paper discharge passage 37.

FIG. 5 shows an example of a color thermosensitive recording material. On the support 41, the cyan thermosensitive coloring layer 4
2, magenta thermosensitive coloring layer 43, yellow thermosensitive coloring layer 4
4, protective layers 45 are sequentially provided. These thermosensitive coloring layers 42 to 44 are provided from the surface in the order of thermal recording. For example, when thermal recording is performed in the order of magenta, yellow, and cyan, a yellow thermosensitive coloring layer and a magenta thermosensitive coloring layer are provided. The positions of the layers are interchanged. Since the deeper the heat-sensitive coloring layers 42 to 44, the higher the coloring heat energy, the three-color heat-sensitive coloring layers 42 to 44 can be selectively recorded by changing the coloring heat energy.

When the magenta thermosensitive coloring layer 43 is irradiated with an ultraviolet ray near 365 nm after the magenta image is thermally recorded by the thermal head 27, the diazonium salt compound undergoes photolysis and loses its coloring ability. The yellow thermosensitive coloring layer 44
Irradiation with near-ultraviolet light near 420 nm causes light fixation and loss of color-forming ability. For this reason, light is fixed even by near-ultraviolet rays of 365 nm having higher energy. Since the magenta thermosensitive coloring layer 43 and the yellow thermosensitive coloring layer 44 contain a diazonium salt compound, the color thermosensitive recording material 10 originally has a light yellow color.

When the thermosensitive coloring layers 43 and 44 are sufficiently light-fixed, the unrecorded portion of the color thermosensitive recording material 10 changes from light yellow to transparent. As the magenta light fixing device 28 and the yellow light fixing device 29, small devices having a small light emission amount are used in order to reduce the size of the apparatus, so that sufficient bleaching cannot be performed by one irradiation. . Therefore,
In order to perform sufficient bleaching and shorten the printing time, in the present embodiment, while the color thermosensitive recording material 10 is discharged, thermal recording of the lowermost cyan thermosensitive coloring layer 42 is performed.
At the same time, the magenta optical fixing device 28 is turned on to irradiate sufficient ultraviolet rays. Further, as a result, the ultraviolet light is also applied to the distal end portion 10a which is shielded by the pressing portion 18a of the clamp arm 18, so that the yellow band in the unfixed state is completely bleached.

Next, the operation of the above embodiment will be described with reference to the sequence shown in FIG. At the time of sheet feeding, the platen drum 10 is stopped at the set position shown in FIG. At this time, the solenoid 25 is turned on and the paper feed lever 23 is turned on.
Is rotated counterclockwise, and the bent portion 21 is pressed by the tip of the paper feed lever 23. As a result, the clamp arm 18 is moved from the clamp position to the paper feed position. During this time, the clamp arm 18 is guided by the flat portion 16a of the platen shaft 16 and slides in the opening 19a. Only be moved.

The transport roller pair 14 is provided with a color thermosensitive recording material 10 supplied from a cassette 11 by a paper feed roller 12.
Is nipped and transported toward the platen drum 15. At the same time that the leading end 10a of the color thermosensitive recording material 10 comes into contact with the stop 18c of the clamp arm 18, the transport roller pair 14 is temporarily stopped, and then the solenoid 25 is turned off.
As a result, the pressing of the bent portion 21 by the sheet feeding lever 23 is released. As a result, the clamp arm 18 is pulled back by the spring 20, so that the distal end portion 10a
Is clamped by the holding portion 18a. After this clamping, the stepping motor 17 is driven, and the platen drum 15 and the transport roller pair 14 rotate. Since the platen drum 15 rotates integrally with the clamp arm 18, the color thermosensitive recording material 10 is wound around the outer peripheral surface 15 a of the platen drum 15.

When the platen drum 15 rotates, the leading end of the recording area of the color thermosensitive recording material 10 is
7, the thermal head 27 thermally records a yellow image line by line. In the thermal recording of this yellow image, each heating element of the thermal head 27
The yellow heat-sensitive coloring layer 44 is heated to a temperature in consideration of the coloring properties. The portion where the yellow image is thermally recorded reaches the yellow optical fixing device 29, where optical fixing is performed. Approximately 420n by the yellow light fixing unit 29
The near-ultraviolet light near m is irradiated on the color thermosensitive recording material 10, and the color is fixed to the extent that yellow does not develop in the next thermal recording of the magenta thermosensitive coloring layer 44.

When the rotation of the platen drum 15 advances and the recording area reaches the position of the thermal head 27 again, a magenta image is thermally recorded on the magenta thermosensitive coloring layer 43 line by line. At the time of thermal recording of the magenta image, the yellow light fixing device 29 is turned off and the magenta light fixing device 2 is replaced.
8 is turned on until the rear end of the color thermosensitive recording material 10 passes. As a result, ultraviolet light having a wavelength of about 365 nm is irradiated to the color thermosensitive recording material 10, and the cyan thermosensitive coloring layer 4 is irradiated with ultraviolet light.
At the time of thermal recording of No. 2, light is fixed to the extent that magenta does not develop color.

Next, when the color thermosensitive recording material 10 faces the thermal head 27, recording of a cyan image is started. Immediately before the recording of the cyan image, the solenoid 26 is turned on, and the paper discharge lever 24 is rotated in the direction of the arrow (clockwise) shown in FIG. As a result, the clamp arm 18 is moved to the paper discharge position to release the clamping of the leading end portion 10a, and also the state shown in FIG.
Since the platen shaft 16 is moved to the opening 19b, the platen drum 15 is disengaged from the clamp arm 18 as shown in FIG.

At the same time, the magenta light fixing device 28 is turned on, and the tip portion 10a, which has been covered with the pressing portion 18a and has become a yellow band, is irradiated with ultraviolet rays to be bleached. Then, the clamp arm 18 abuts against the stopper 36 and the rotation thereof is stopped at that position. However, since the platen drum 15 is continuously rotated by the stepping motor 17, the color thermosensitive recording material 10 passes under the stop portion 18c. And is conveyed toward the paper discharge path 37.

At the time of paper ejection, a cyan image is thermally recorded line by line on the cyan thermosensitive coloring layer 42 of the color thermosensitive recording material 10 by the thermal head 27, and immediately thereafter, ultraviolet light is irradiated from the magenta optical fixing device 28 to color. The thermal recording material 10 is sufficiently bleached.

As the rotation of the platen drum 15 proceeds, FIG.
As shown in (C), after the rotation angle of the platen shaft 16 exceeds 180 ° from the start of the sheet discharge, the solenoid 26 is turned off. At this time, the clamp arm 18 is likely to be pulled back toward the clamp position by the spring 20, but since the flat portion 16a is not parallel to the longitudinal direction of the elongated hole 19, the boundary portion 19c between the opening 19a and the opening 19b is located on the platen shaft. 16 is not returned to the sheet feeding position by abutting on the outer peripheral surface.

When the rear end portion 10b of the color thermosensitive recording material 10 passes the stop position of the clamp arm 18 and the platen drum 15 makes one rotation and returns to the paper discharge start position, the flat portion 16
a is parallel to the longitudinal direction of the elongated hole 19 and the platen shaft 16
Can be moved from the opening 19b to the opening 19a, and the clamp arm 18 is returned to the clamp position by the bias of the spring 20. On the other hand, the color thermosensitive recording material 10 is nipped by a pair of conveying rollers 39 through a paper discharge path 37 and discharged to a paper discharge tray 38.

In the embodiment described above, the entire platen shaft is formed in a D-shaped cross section. However, only the portion engaging with the elongated hole of the clamp arm may be formed in a D-shaped cross section. Further, in this embodiment, the magenta optical fixing device 28 is turned on again immediately before the recording of the cyan image is started. However, the light fixing device 28 may be turned on continuously after the magenta image is fixed.

The above embodiment is an example in which a thermal head or a color thermal recording material is applied to a line printer for recording by relatively moving in the sub-scanning direction. It can also be applied to This serial printer uses a thermal head in which heating elements are arranged in the main scanning direction, moves in the sub-scanning direction during thermal recording, and the color thermosensitive recording material moves in the main scanning direction.

[0028]

As described above in detail, according to the clamp device of the present invention, at least a part of the platen shaft has a substantially D-shaped cross-sectional shape, and the oblong hole of the clamp arm inserted therethrough. Is constituted by two openings having different widths, it is possible to keep the portion of the platen drum pressed by the clamp arm constant without providing a separate component such as a guide pin on the platen drum, contributing to a low cost printer. it can.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a clamp device of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a platen shaft and a long hole.

FIG. 3 is a schematic view of the color thermal printer showing a state where a clamp arm is at a paper feeding position.

FIG. 4 is a schematic view of the color thermal printer showing a state where a clamp arm is at a paper discharge position.

FIG. 5 is an explanatory diagram showing a layer structure of a color thermosensitive recording material.

FIG. 6 is a flowchart showing a sequence of the color thermal printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Color thermosensitive recording material 15 Platen drum 16 Platen shaft 16a Flat part 18 Clamp arm 18a Holding part 19 Slot 19a, 19b Opening 20 Spring 23 Feed lever 24 Discharge lever 25, 26 Solenoid 27 Thermal head 28 Magenta light Fixing unit 29 Optical fixing unit for yellow

Claims (1)

(57) [Claims] 1. A printer for recording by winding a recording paper around an outer periphery of a platen drum, wherein a clamp arm for clamping a leading end of the recording paper is mounted on the outer periphery of the platen drum via a platen shaft of the platen drum. At least a part of the platen shaft has a substantially D-shaped cross-sectional shape, and a long hole of the clamp arm inserted into the platen shaft is formed by the clamp arm and the platen drum when the clamp arm is set at the clamp position. And the platen drum is independent of the clamp arm when the clamp arm is set to the discharge position so that the relative position of A wide opening having an inner diameter larger than a diameter of a platen shaft so that the platen shaft can be rotated. Clamping device.