JP2005138376A - Transfer device and thermal transfer printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a mechanism for applying a constant tension to a rolled medium at all times through a simple structure regardless of variation in diameter of the medium when various kinds of stripe medium, e.g. an ink ribbon, stretched between a feed roller and a winding roller is transferred in a thermal transfer printer. <P>SOLUTION: The transfer device 120 for transferring a stripe medium R wound around each roller of first and second transfer mechanisms while being stretched between two transfer mechanisms by winding the roller of the second transfer mechanism is provided with a control roller 304 being pressed with the predetermined pressure against the medium R wound around the roller 120a of the first transfer mechanism and rotating as the medium R is transferred, and torque limiters 305-1 and 305-2 for controlling torque of the control roller 304 during rotation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermal transfer printing apparatus that performs thermal melting recording and thermal sublimation recording, and a transfer device that can be applied to the printing apparatus and transports a belt-like medium such as an ink ribbon.

  Generally, a thermal transfer printing apparatus (thermal transfer printing apparatus) that performs thermal melting recording or thermal sublimation recording sublimates ink ribbon ink by a print head in a state where the ink ribbon is superimposed on a recording medium such as photographic paper. Alternatively, the image is printed on the recording medium by melting.

  The ink ribbon set in the thermal transfer printing apparatus is stretched between a so-called supply roller and a take-up roller, and is superposed on a recording medium with an appropriate tension applied to the ink ribbon. High quality printing can be realized.

  As a method for applying an appropriate tension, for example, when a torque limiter is arranged on the rotation shaft of the supply roller and a predetermined torque is applied to the rotation shaft (that is, the ink ribbon is pulled with a certain tension). In addition, a mechanism has been proposed that allows an appropriate back tension to be applied to the ink ribbon by setting it to rotate. According to such a mechanism, a back tension can be applied to the ink ribbon, and an excessive tension is not applied.

  However, the method of arranging the torque limiter on the rotating shaft has a problem that the back tension changes as the diameter of the ink ribbon wound at the start and end of winding of the ink ribbon varies. For example, the tension applied to the ink ribbon is small because the diameter of the ink ribbon is about φ60 mm at the start of winding, but the tension applied to the ink ribbon increases because the diameter of the ink ribbon reaches about φ30 mm at the end of winding. End up.

Therefore, in Patent Document 1 below, a sensor for detecting the diameter of the ink ribbon is provided, and when the back tension is required (when the diameter of the ink ribbon is large) according to preset setting information, the winding side is excited and the ink ribbon is excited. A technique has been proposed in which a constant tension is always applied to the ink ribbon by exciting the feed side when the diameter of the ink ribbon becomes smaller.
Japanese Patent Laid-Open No. 08-002078

  However, according to the above prior art, it is necessary to provide a complicated control system such as excitation on the winding side or the feeding side based on the output from the sensor, and it is difficult to adjust the optimum control gain. There's a problem. Therefore, it is desired to realize a transfer device capable of always applying a constant tension to the transferred ink ribbon with a simple mechanism.

  The present invention has been made in view of such problems, and is wound in a roll shape when transporting various belt-like media such as an ink ribbon stretched between a supply roller and a take-up roller. An object of the present invention is to realize a mechanism capable of constantly applying a constant tension to the medium with a simple structure regardless of fluctuations in the diameter of the medium.

In order to achieve the above object, a transfer apparatus according to the present invention has the following configuration. That is,
The roller of the second transfer mechanism winds the belt-shaped medium wound around each roller included in the first transfer mechanism and the second transfer mechanism and stretched between the two transfer mechanisms. A transfer device for transferring the medium between the transfer mechanisms by taking,
A control roller that is pressed with a predetermined pressure against a medium wound in a roll around a roller included in the first transfer mechanism, and rotates in accordance with the transfer of the medium;
A torque limiter for controlling torque during rotation of the control roller.

  According to the present invention, when various belt-shaped media such as an ink ribbon stretched between a supply roller and a take-up roller are transferred, the media is irrespective of fluctuations in the diameter of the media wound around the rollers. On the other hand, a mechanism capable of always applying a constant tension can be realized with a simple structure.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[First embodiment]
First, the outline of the present invention will be briefly described. As described above, conventionally, a torque limiter is arranged on the rotary shaft of the take-up roller, and a constant load is applied to the rotary shaft. Therefore, when the diameter of the ink ribbon is large, the tension applied to the ink ribbon is small. When the diameter of the ink ribbon is small, the tension applied to the ink ribbon is large.

  In contrast, according to the present invention, a tension is applied to the ink ribbon by pressing another roller against the outer surface of the ink ribbon wound around the roller at a constant pressure, and the rotation axis of the pressed roller is applied to the roller. By arranging a torque limiter, the tension of the ink ribbon is controlled to be constant. In other words, by adopting a structure in which tension is directly applied to the ink ribbon, it is possible to always apply a constant tension to the ink ribbon even if the diameter of the ink ribbon varies. As described above, according to the present invention, since the torque limiter is arranged on the rotating shaft of the roller pressed at a constant pressure and the torque is controlled mechanically, the above-described problem can be solved with a simple structure without requiring a complicated control system. There is an effect. Hereinafter, a sublimation printer is taken as an example of a thermal transfer printing apparatus to which the transfer device having such a structure is applied, and after describing the overall configuration and operation of the printer, the transfer device in the sublimation printer will be described in detail. . The thermal transfer printing apparatus to which the transfer apparatus having the above structure is applied is not limited to a sublimation type printer, and may be a melt type printer.

<Overall configuration of sublimation printer>
FIG. 1 is an external perspective view showing an example of a sublimation printer. The sublimation printer 100 is assumed to be a photo printing printer including a printer main body 101 and a drawer 102 provided so as to be able to be pulled out from the printer main body 101.

  A cover 101 a that can be opened and closed is provided on the upper surface of the printer main body 101. When the cover 101a is rotated (arrow D1) to be opened, the inside of the printer main body 101 is exposed, and the ink ribbon cassette 120 (transfer device) can be exchangeably attached thereto (arrow D3). The ink ribbon cassette 120 is rotatably provided with an ink ribbon supply roller 120a around which the ink ribbon R is wound, and a take-up roller 120b that winds up the used ink ribbon R from the ink ribbon supply roller 120a. (The details will be described later). Further, a slit 101 b for discharging a recording medium printed by the sublimation printer 100 is provided in the vicinity of the center of the front surface of the printer main body 101.

  The drawer portion 102 includes a front panel 1021 and a pair of left and right side plates 1022. The drawer portion 102 is pulled out from the printer main body portion 101 (arrow D 2) by operating a handle 1021 a provided on the front panel 1021. Can be returned.

  Roll paper RP is loaded between the side plates 1022 in the drawer 102 so as to be replaceable. Bearings 1023 are attached to the inner sides of the respective side plates 1022, and are supported by the bearings 1023 by the roller shafts 103 inserted into the center holes of the roll paper RP, and are configured to be rotatable. The bearing 1023 has a notch opened upward, and the shaft 103 is dropped into the notch to support it. When the roll paper RP is lifted upward, the shaft 103 is disengaged from the bearing 1023, whereby the roll paper RP can be replaced.

  A pair of left and right guide rails 1024 extending to the rear of the drawer portion 102 are provided at the bottom of the drawer portion 102. The guide rail 1024 is supported by a guide 104 fixed on the bottom plate of the printer main body 101. The guide rail 1024 is guided by the guide 104, so that the drawer portion 102 can be taken in and out of the printer main body 101. can do.

  On the back surface of the front panel 1021 of the drawer portion 102, a container 1028 having an open top for accommodating a cut piece of the roll paper RP is detachably mounted.

  A pair of rollers 1025 and 1026 that sandwich and convey the roll paper RP is provided behind the drawer unit 102. The roller 1025 is rotatably supported between the side plates 1022, and the roller 1026 is rotatably supported between a pair of rotating plates 1027 that are rotatably supported by the side plates 1022 via pins 1027a. ing. The pair of rotating plates 1027 and the rollers 1026 are formed in a U-shaped frame and rotate as a whole around the pin 1027a.

<Description of operation of sublimation printer>
FIG. 2 is an explanatory diagram of the operation of the sublimation printer 100. After the setting of the roll paper RP is completed, the drawer unit 102 is returned to the original position, and the print standby state is entered.

  The roll paper RP set with the leading end held between the rollers 1025 and 1026 is first conveyed upward in the figure by urging the roller 1025 with a rotational force. The rotational force urged by the roller 1025 is generated by the motor 105 and transmitted through the belt 106 and the pulley 107. A gear that meshes with a gear 1025a attached to the roller 1025 is attached to the pulley 107, and when the pulley 107 rotates, the roller 1025 also rotates.

  Due to the rotation of the roller 1025, the leading edge of the roll paper RP is next guided by the guide plate 108a toward the guide guide 109 that changes the conveyance direction of the roll paper RP to a substantially right angle. The guide guide 109 has an inner curved surface whose surface is smoothed, and a guide roller 110 is provided facing the inner curved surface. The leading edge of the roll paper RP passes through a gap between the inner curved surface of the guide guide 109 and the guide roller 110, is guided by the inner curved surface of the guide guide 109, and bends at a substantially right angle.

  When the leading edge of the roll paper RP passes through the guide roller 110, it is sandwiched between the pinch roller 111 and the conveying roller 112 and further conveyed by the rotation of the conveying roller 112. The conveyance roller 112 is attached to the pulley 112a, and rotates when the rotational force of the motor 105 is transmitted to the conveyance roller 112 via the belt 106 and the pulley 112a.

  The roll paper RP is inserted between the thermal head 113 and the platen roller 114 by the rotation of the transport roller 112. An ink ribbon R is inserted between the thermal head 113 and the platen roller 114, and the ink on the ink ribbon R is sublimated by the thermal head 113 to perform image printing on the roll paper RP. In the case of color printing, the ink ribbon R is repeatedly provided with an ink layer of each color of yellow (Y), magenta (M), and cyan (C) and an overcoat layer serving as a protective layer in predetermined units. By repeating the forward rotation and reverse rotation of the transport roller 112 and reciprocating the roll paper RP, printing of each color and overcoat are performed. The used ink ribbon R is sequentially wound by a winding roller 120b that is rotated by a driving mechanism (not shown).

  The printed roll paper RP is guided by the guide plate 108c to the cutting machine 115, and is cut into a single photograph by being cut at a predetermined size. The cutting machine 115 cuts the blank space provided between the photographs. Thereafter, the photograph is guided by the guide plate 108d, and discharged from the slit 101b to the outside of the sublimation printer 100 by its own weight. On the other hand, the cut piece CS generated by cutting the blank portion of the roll paper RP falls due to its own weight and is accommodated in the container 1028 disposed at the dropping position (below the cutting machine 115). It becomes.

  The container 1028 is made of metal, is detachably attached to the front panel 1021 by a magnet 1021b fixed to the back surface of the front panel 1021, and is positioned by a guide member 1021c attached to the front panel 1021. By repeating the above procedure, images such as photographs are sequentially printed.

<Ink ribbon cassette structure>
FIG. 3 is a diagram showing the ink ribbon supply roller 120a and its peripheral mechanism in the ink ribbon cassette 120 (transfer device) constituting the sublimation type printer 100. In FIG. 3A, reference numerals 301-1 and 301-2 denote bearings for the ink ribbon supply roller 120a and are attached to the housing 302 of the ink ribbon cassette 120. Reference numeral 304 denotes a torque control roller having a cylindrical shape, and is attached to the roller mount 306 via torque limiters 305-1 and 305-2. As a result, the torque control roller 304 rotates when a constant torque is applied. Further, the roller mount 306 is rotatably supported by the housing 302 of the ink ribbon cassette 120, and one end thereof is connected to springs 303-1 and 303-2 attached to the ink ribbon cassette 120.

  FIG. 3B is a diagram showing a positional relationship between the ink ribbon supply roller 120a around which the ink ribbon R is wound and the roller mount 306 to which the torque control roller 304 is attached. As shown in the figure, the roller mount 306 is pulled in the direction of the arrow by springs 303-1 and 303-2 around a fulcrum 307. As a result, the torque control roller 304 comes into contact with the outer peripheral surface of the ink ribbon R in a state of being pressed with a predetermined pressure.

  With this configuration, the torque control roller 304 rotates following the winding of the ink ribbon, and a certain amount of force is applied in a direction that prevents the supply of the ink ribbon. The constant amount of force applied at this time is determined by the torque limiters 305-1 and 305-2 attached to the rotation shaft of the torque control roller 304, and no tension exceeding a certain tension is applied to the ink ribbon.

  FIG. 4 shows the positional relationship between the ink ribbon R and the torque control roller 704 at the start of winding of the ink ribbon R (see (A)), and the ink ribbon R and torque control at the end of winding of the ink ribbon R. The positional relationship with the roller 304 (see (B)) is shown respectively.

  As shown in the figure, the distance from the rotation center of the ink ribbon supply roller 120a to the outer peripheral surface of the ink ribbon differs greatly at the start and end of winding of the ink ribbon. For this reason, even if the ink ribbon supply roller 120a is rotated by attaching a torque limiter to the rotation shaft of the ink ribbon supply roller 120a and applying a constant torque to the rotation shaft as in the prior art, the ink ribbon at that time The back tension of R depends on the distance from the rotation center of the ink ribbon supply roller 120a to the outer peripheral surface of the ink ribbon. For this reason, the tension applied to the ink ribbon changes at the start and end of winding of the ink ribbon.

  On the other hand, as shown in FIG. 4, in the ink ribbon cassette (transfer device) according to the present embodiment, the torque control roller 304 is attached so as to be rotatable around the fulcrum 307, and the springs 303-1 and 303-2. Therefore, the outer peripheral surface of the ink ribbon R can be pressed with a constant pressure. At this time, since torque limiters 305-1 and 305-2 are attached to the torque control roller 304, a certain amount of force is applied in a direction that prevents the supply of the ink ribbon R. As a result, a constant back tension is applied to the ink ribbon R.

  The force in the direction that prevents the supply of the ink ribbon R varies depending on the pressing force when the torque control roller 304 is pressed against the outer peripheral surface of the ink ribbon R by the springs 303-1 and 303-2. Therefore, the fulcrum 307 and the springs 303-1 and 303-2 are arranged so that a constant pressing force is applied regardless of the change in the distance from the rotation center of the ink ribbon supply roller 120 a to the outer peripheral surface of the ink ribbon R. It is desirable.

  In this way, by adopting a structure in which tension is directly applied to the ink ribbon, even if the distance from the rotation center of the ink ribbon supply roller to the outer peripheral surface of the ink ribbon varies, a constant tension is always applied to the ink ribbon. It becomes possible. Further, since the torque is mechanically controlled, there is an effect that it can be realized with a simple structure without requiring a complicated control system.

[Second Embodiment]
In the first embodiment, the shape of the torque control roller has a cylindrical shape. However, the shape is not limited to this, and as shown in FIG. It may be a large drum shape.

  FIG. 5 is a view showing a torque control roller according to the present embodiment. As shown in the figure, for a 170 mm wide roller, the outer diameter of the roller center is 16 mm, the outer diameter of the roller end is 12 mm, and the cross-sectional shape in the width direction of the roller is smooth from the center to the end. It has a curve.

  By having such a shape, in the first embodiment, the torque control roller presses the ink ribbon, and there is a possibility that crimping and wrinkling may occur on the ink ribbon. The generation of wrinkles can be avoided. In other words, pressing with the drum-shaped roller adds a force to the ink ribbon to extend outward in the width direction, and even if the ink ribbon sags at the center, the ink ribbon is extended outward.

  As is apparent from the above description, according to the present embodiment, it is possible to apply a constant back tension to the ink ribbon, and it is also possible to avoid the occurrence of crimping and wrinkling of the ink ribbon.

[Third Embodiment]
In the second embodiment, the generation of the crimping wrinkle is avoided by changing the shape of the torque control roller. However, the present invention is not limited to this. By generating a spiral groove on the torque control roller from the center position in the width direction toward the outside in the width direction, the occurrence of crimping wrinkles may be avoided.

  FIG. 6 is a view showing a torque control roller according to the present embodiment. As shown in the figure, the cross-sectional shape of the groove is a triangle (see FIG. 6B) or a quadrangle (see FIG. 6C), the groove depth is 1.25 mm, and the groove opening. The width is 2.5 mm. However, the present invention is not limited to the dimensions, and may be changed according to the material of the ink ribbon.

  Further, in the present embodiment, the rotational pitch of the grooves is 3 rotations per half of the roller width (here, 85 mm) in the width direction of the torque control roller. That is, the groove has a pitch of moving 22 mm outward in the width direction every time the roller is rotated once, and has an angle of 43.15 degrees with respect to a plane perpendicular to the width direction of the roller (FIG. 6 ( A)). However, the rotation pitch is not limited to this. That is, in this embodiment, since the rotation speed of the roller is 77 rpm, this rotation pitch is optimal. However, if the rotation speed of the roller is different, the rotation speed of the groove also changes, so that the winding speed of the ink ribbon is increased. It is desirable to design accordingly.

  As is apparent from the above description, according to the present embodiment, it is possible to apply a constant back tension to the ink ribbon, and it is also possible to avoid the occurrence of crimping and wrinkling of the ink ribbon.

1 is a diagram illustrating an external configuration of a thermal transfer printing apparatus (sublimation printer) according to an embodiment of the present invention. It is operation | movement explanatory drawing of a sublimation type printer. It is a figure which shows an ink ribbon supply roller and its peripheral mechanism among the ink ribbon cassettes which comprise a sublimation type printer. FIG. 4 shows a positional relationship with a torque control roller at the start of ink ribbon winding and a positional relationship with a torque control roller at the end of ink ribbon winding. It is a figure which shows the roller for torque control of the transfer apparatus (ink ribbon cassette) concerning the 2nd Embodiment of this invention. It is a figure which shows the roller for torque control of the transfer apparatus (ink ribbon cassette) concerning the 3rd Embodiment of this invention.

Explanation of symbols

RP roll paper R ink ribbon 100 sublimation printer 101 printer main body portion 102 drawer portion 120 ink ribbon cassette 120a ink ribbon supply roller 120b ink ribbon take-up roller 113 thermal head 114 platen roller 301-1, 2 bearing 302 housing 303-1, 2 Spring 304 Torque control roller 305-1, Torque limiter 306 Roller mount 307

Claims (5)

The roller of the second transfer mechanism winds the belt-shaped medium wound around each roller included in the first transfer mechanism and the second transfer mechanism and stretched between the two transfer mechanisms. A transfer device for transferring the medium between the transfer mechanisms by taking,
A control roller that is pressed with a predetermined pressure against a medium wound in a roll around a roller included in the first transfer mechanism, and rotates in accordance with the transfer of the medium;
A transfer device comprising: a torque limiter that controls torque during rotation of the control roller. The said control roller is supported by the mount attached so that rotation was possible, and this roll is pressed to the said medium by pulling this stand with an elastic body. Transfer device. 2. The transfer device according to claim 1, wherein the control roller has an outer diameter of a roller center portion larger than an outer diameter of a roller end portion. The transfer device according to claim 1, wherein the control roller has a spiral groove from the roller center to the roller end. A thermal transfer printing apparatus comprising the transfer device according to claim 1.

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