JP2002347263A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable of controlling the ribbon tension to a necessary and sufficient level at the time of finding the top of a ribbon and at the time of printing. SOLUTION: In a thermal sublimation type image recording apparatus for recording an image by heating an ink ribbon 3 with a thermal head 32 and transferring the heated color material to a recording medium, a main friction clutch 6 and a sub friction clutch 16 are provided for changing over the friction of the ribbon 3 to a higher or lower level such that a large torque is applied on the taking out side core 1 by the main friction clutch 6 at the time of printing so as to control the ribbon tension at the higher side, and a small torque is applied on the taking out side core 1 according to changeover to the sub friction clutch 16 side at the time of finding the top of the ribbon so as to control the ribbon tension at the lower side. Thereby, a trouble derived from excessive or insufficient tension of the ribbon can be solved as well as a high quality color image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal sublimation type image recording apparatus for recording an image on a recording medium by heating an ink ribbon by a thermal head and transferring the heated coloring material to the recording medium. .

[0002]

2. Description of the Related Art In a thermal sublimation type image recording apparatus, a two-roll type ink ribbon having a ribbon core on both a winding side and a feeding side, or a ribbon cassette containing a two-roll type ink ribbon is used. When the ribbon core of the ribbon cassette is set in the image recording apparatus, the winding-side core fits into a winding-side core boss driven directly by a motor or via a clutch mechanism, and the feeding-side core has friction. A constant torque is applied to the pay-out core through a clutch or the like to fit the pay-out core boss that applies tension to the ribbon.

As is apparent from this configuration, since the torque applied by a friction clutch or the like to the conventional delivery-side core is always constant, the following problem occurs. 1. At the time of cueing, the torque of the winding-side core needs to be larger than the torque of the feeding-side core. For this reason, especially when a ribbon having a large ribbon winding amount is used, the difference in the winding diameter is inversely proportional to the ribbon tension, so that the adjustment range of the torque setting on the winding side and the feeding side becomes very small. As a result, the ribbon may be wrinkled due to insufficient tension, causing print misalignment, or the ribbon may be easily broken due to excessive tension. 2. If the feeding side torque is set to be small, the above-mentioned problem 1 can be solved, but conversely, cueing cannot be accurately performed due to insufficient ribbon tension, or problems such as printing deviation due to insufficient tension at the time of printing occur. High quality images cannot be obtained. 3. Since the ribbon tension is adjusted at the time of printing,
Since the tension is excessive during cueing, the cueing speed is delayed and the amount of electric power consumed by the motor during cueing increases.

[0004]

As described above, as described above,
In a conventional image recording apparatus, since a single friction clutch applies a torque to the feeding side core based on the ribbon tension at the time of printing, the ribbon tension at the time of cueing is excessive. It is necessary to release excessive tension at the time of delivery. On the other hand, in printing, it is necessary to apply a sufficient tension to the ribbon in order to record a high-quality image.

The present invention has been made in view of the above points, and a first object of the present invention is to provide an apparatus for controlling a ribbon tension to be necessary and sufficient at the time of ribbon cueing and printing. It is to provide. Further, the second purpose is in synchronization with the elevation of the thermal head, that is, when the thermal head is lowered, it is at the time of printing.
At this time, the ribbon tension (torque) is controlled to a large value, and when the thermal head rises, it is at the time of ribbon cueing. At this time, the ribbon tension (torque) is automatically controlled (switched) to a small value. It is to provide a device.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, in an image recording apparatus, an ink ribbon is heated by a thermal head, and the heated coloring material is transferred to a recording medium. In the thermal sublimation type image recording apparatus which records an image by performing the operation, a tension switching means for switching the tension of the ink ribbon to a large or small value is provided on the ribbon feeding side, and the tension switching means is switched to the large tension side at the time of image recording. In addition, it is configured to switch to the small side at the time of ribbon cueing.

Further, in the invention according to claim 2,
According to the first aspect of the present invention, the tension switching means can be switched in synchronization with the vertical movement of the thermal head by attaching a tension switching cam to a thermal head lifting / lowering cam shaft for driving the thermal head up and down. It is characterized by having done.

Further, in the invention according to claim 3,
According to the first aspect of the present invention, the tension switching means includes a main friction clutch that controls the tension to a large side in synchronization with the elevation of the thermal head, and a sub friction clutch that controls the tension to a small side. Things.

[0009]

The operation of the image recording apparatus having the ribbon tension switching means according to the present invention will be described below. First, the thermal transfer ribbon of the image recording apparatus is based on three primary colors of yellow, magenta, and cyan, and is color-coded periodically for each color.
The ribbon is wound around a feeding-side core of a ribbon cassette, and the leading end is tied to a winding-side core. This ribbon cassette is set in the image recording apparatus.

First, in the operation start state, the thermal head and the ribbon are separated from the platen drum,
The recording medium can be transported. In this state, the printing medium is conveyed, that is, fed, and the printing medium is started after the head side of the printing medium is fixed between the platen drums by the clamper.

After the printing operation is started, first, an arbitrary color of the thermal transfer ribbon is searched. At this time, the thermal head rises by the action of the thermal head elevating camshaft and is separated from the platen drum, so that the tension switching cam attached to the thermal head elevating camshaft to switch the tension switching means moves to the sub friction clutch side. Since the ribbon is switched, a small tension is generated in the ribbon, and the cueing can be smoothly performed. Next, the platen drum rotates so that the recording medium comes to the printing start position, and the position of the platen drum, that is, the cueing of the recording medium is performed. After the cueing is completed, the thermal head elevating cam moves (falls) the thermal head toward the platen drum and applies an appropriate pressure in order to bring the thermal transfer ribbon and the recording medium into close contact. In synchronization with this movement, the tension switching cam switches to the main friction clutch side, and a greater tension is generated on the ribbon as compared with the above-mentioned cueing.

Next, the thermal head is energized in accordance with an arbitrary dot to generate heat by synchronizing with rotation of the platen drum, and heat is generated. The color material is thermally transferred by the heat and the pressure between the thermal head and the platen drum. The image is recorded by transferring the image from the ribbon to the recording medium. After the completion of the first color, the thermal head is separated from the platen drum, and the thermal transfer ribbon is fed to find the next color. Next, the platen drum is rotated, and the cue of the recording medium is performed again. By the above operation, the tension acting on the ribbon is automatically switched optimally at the time of cueing and printing, so that the driving force required for ribbon conveyance can be reduced, speeding up ribbon feeding and saving power. In addition, the cost can be reduced. It is also possible to improve the quality of the recorded image.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the first to third aspects of the present invention will be described in detail with reference to FIGS. However, this FIG.
FIG. 5 is a view showing known components such as a platen drum, a paper feeder, and the like in the image recording apparatus.
Since it is basically the same as that described in JP-A-01-47651, it is omitted and only the main part is shown.

First, in FIG. 1, reference numeral 1 denotes a feeding core incorporated in a ribbon cassette (not shown), 2 denotes a winding core, and 3 denotes a known thermal transfer ribbon. Reference numeral 4 denotes a core boss to which the feeding-side core 1 is fitted,
The core boss 4 is connected to the main friction clutch 6 via a rotating shaft 5.

As shown in FIGS. 1 and 2, the main friction clutch 6 includes a main friction disk 7 having a felt 9 fixed to the payout side rotation shaft 5 by a pin 8 and a spring 12 having an adjustable elasticity. The main friction disk 7
The sliding friction disk 10 with the felt 11 pushed out to the side, the main friction disk 7 and the sliding friction disk 10 are sandwiched between the felts 9 and 11 via the felts 9 and 11, and are free to the feeding side rotating shaft 5. And a main friction clutch gear 13 mounted on the main friction clutch gear 13.

In FIG. 2, reference numeral 14 denotes a presser for the spring 12, and the elasticity of the spring 12 can be adjusted by sliding the presser 14 on the feed-out rotary shaft 5 with a screw or the like. Reference numeral 15 denotes a bearing with a bearing attached to the frame a. Reference numeral 16 denotes a sub-friction clutch. As shown in FIGS. 1 and 3, the sub-friction clutch 16 has a main friction clutch gear 13 and a sub-friction clutch gear 17 engaged with the sub-friction clutch gear 17. It is freely attached to the clutch shaft 18. Reference numeral 19 denotes a cylindrical shaft attached to the sub clutch shaft 18 by a pin 19a, and a receiving disk 19b is formed on the side of the cylindrical shaft 19 on the side of the sub friction clutch gear 17. Reference numeral 20 denotes a sub-friction clutch disk which engages the engagement claw 20a with the sub-friction clutch gear 17 and is freely mounted on the cylindrical shaft 19, and is provided between the sub-friction clutch disk 20 and the receiving disk 19b. Has a felt 21 interposed.

Reference numeral 22 denotes a sub-friction disk which is freely attached to the cylinder shaft 19. The sub-friction disk 22 is pressed by a spring 23 toward the sub-friction clutch disk 20 via a felt 24. . The elasticity of the spring 23 is adjustable by a spring receiver 25.

In FIG. 1, reference numeral 26 denotes a switching arm which is rotatably mounted on a frame a by a central arm rotating shaft 27, and has a stop gear at the end of the arm 26 which can be engaged with the main friction clutch gear 13. 2
8 is mounted, and a cam receiving pin 29 is mounted on the opposite side. Also, the arm 26 is pivoted about an arm rotation shaft 27 so that the stop gear 28 meshes with the main friction clutch gear 13 as shown in FIG.
, An arm tension spring 30 for applying a force to rotate clockwise is provided.

Reference numeral 31 denotes a thermal head elevating camshaft to which a cam 33 for elevating and lowering the thermal head 32 is attached. The rotation of the camshaft 31 causes the thermal head 32 to escape upward when the ribbon is caught and prints. Sometimes, it descends and comes into contact with the ribbon to heat it.

Numeral 34 denotes a clutch switching cam mounted on a camshaft 31. The cam 34 is engaged with a cam receiving pin 29 of the arm 26, and the thermal head 32 is lifted to locate the ribbon. Sometimes arm 26
The arm 26 is rotated counterclockwise about the rotation shaft 27 by lowering the cam receiving pin 29 side against the tension spring 30, and the stop gear 28 is separated from the main friction clutch gear 13 so that the main friction clutch gear 13 The main friction disk 7 and the slide friction disk 10 are controlled so as to rotate while receiving constant friction. As a result, the main friction clutch gear 13 rotates the sub friction clutch gear 17, and this rotation rotates the sub friction clutch disc 20 and the cylindrical shaft 19, and at this time, the felt 24 and the receiving disk 19b on the sub friction disc 22 side are rotated. And the felt 21 in the sub-friction clutch disc 20 applies a small torque to the sub-friction clutch disc 20, that is, the brake is weakly applied. The tension is transmitted from the shaft 5 to the delivery-side core boss 4 → the delivery-side core 1 → the ribbon 3 to generate a small tension on the ribbon at the time of cueing (see FIG. 4).

Conversely, when the camshaft 31 rotates so that the thermal head 32 moves down, the clutch switching cam 34 escapes from the cam receiving pin 29 as shown in FIG. Reference numeral 26 rotates clockwise, and a stop gear 28 meshes with the main friction clutch gear 13 to fix the main friction clutch gear 13. As a result, since the main friction disc 7 and the slide friction disc 10 are pressed against the main friction clutch gear 13 from both sides via the felts 9 and 11, a large torque, that is, a strong brake is applied to the rotary shaft 5 by this friction. This brake is transmitted from the rotating shaft 5 to the core boss 4 on the delivery side → the core 1 on the delivery side → the ribbon 3.
Large tension is applied to the ribbon during printing.

Reference numeral 35 denotes a take-up core boss rotated by a drive motor (not shown). The take-up core 2 rotates to take up the ribbon 3. The tension applied to the ribbon 3 is determined by the winding torque and the braking action of the main friction clutch 6 or the sub friction clutch 16 described above.

[0023]

As described above, according to the present invention, the ribbon tension is controlled to be small by switching from a large load (torque) of the main friction clutch to a small load (torque) of the sub-friction clutch at the time of cueing of the ribbon. Can stabilize cueing. Further, the following effects are obtained. 1. Since the ribbon tension can be set small at the time of ribbon cueing, the driving force required for transporting the ribbon can be reduced accordingly, and high speed and power saving can be achieved. 2. At the time of ribbon cueing, the ribbon tension can be set small, so that the ribbon is less likely to be broken, and a ribbon that is easily broken can be used. 3. At the time of printing, a large tension can be applied to the ribbon as required by the main friction clutch, so that the transferability is improved and a high-quality color image without color shift can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a ribbon tension device according to the present invention.

FIG. 2 is an explanatory diagram of a main friction clutch.

FIG. 3 is an explanatory diagram of a sub friction clutch.

FIG. 4 is an explanatory diagram of an operation of a sub friction clutch at the time of cueing.

FIG. 5 is an explanatory diagram of an operation of a main friction clutch during printing.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 feeding core 2 take-up core 6 main friction clutch 13 main friction clutch gear 16 sub friction clutch 17 sub friction clutch gear 20 sub friction clutch disc 26 arm 28 stop gear

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C065 AB10 DA03 DA20 DA37 2C068 AA02 AA08 FF14 FF19

Claims (3)

[Claims] In a thermal sublimation type image recording apparatus for recording an image by heating an ink ribbon by a thermal head and transferring the heated color material to a recording medium, the tension of the ink ribbon is increased or decreased on a ribbon feeding side. An image recording apparatus comprising: a tension switching unit for switching to a small position; switching the tension switching unit to a large tension position when recording an image; 2. A configuration in which a tension switching cam is attached to a thermal head lifting / lowering cam shaft for driving the thermal head up and down, so that the tension switching means can be switched in synchronization with the vertical movement of the thermal head. Item 2. The image recording apparatus according to Item 1. 3. The tension switching means comprises a main friction clutch for controlling the tension to a large side in synchronism with the elevation of the thermal head, and a sub-friction clutch for controlling the tension to a small side. 2. The image recording apparatus according to 2.