JPH04363245A - Film feed control method - Google Patents

Abstract

PURPOSE:To shorten the transfer film feed time per heat transfer cycle to make a high speed decoration image transfer possible and avoid the waste of the transfer film in the transfer of decoration image on the surface of work using transfer film. CONSTITUTION:A heat transfer is carried out with transfer film X held against the surface of work W by a transfer roll 9 and wound on a film winding shaft and the film winding is stopped by detecting a positioning mark M depicted on the transfer film X with a mark detecting sensor 13 during the heat transfer operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film control method when a transfer film is used to decorate the surface of an object to be transferred.

0002

2. Description of the Related Art As a thermal transfer device for manufacturing decorated products by transferring designs, such as designs and letters, onto the surface of resin molded products, a transfer film X having a transfer layer on the film surface is used as shown in FIG. The object W to be transferred (hereinafter referred to as a work) is carried directly under the transfer roll A and the transfer film X while passing under the rotating and heated transfer roll A, and the transfer film X is transferred to the transfer roll A. Work by W
Transfer film
A roll-type thermal transfer device is known that transfers a transfer layer onto a workpiece W in a predetermined pattern.

[0003] In this case, in the film feeding control in the above-mentioned roll-type thermal transfer device, the transfer roll A is lowered in response to a start signal while the transfer film X is wound around the guide rollers B, Immediately after the start of the thermal transfer operation in which the transfer film X contacts the workpiece W, the transfer film X is wound on the film winding side, and the film winding is stopped as the transfer roll A rises upon completion of the thermal transfer operation. I will let you do it. Therefore, in addition to controlling the feed amount of the transfer film for each thermal transfer operation, the transfer film A positioning mark M is drawn every time the thermal transfer operation is completed, and after the thermal transfer operation is completed, the positioning mark M is detected by a mark detection sensor S and winding of the transfer film X is stopped.

0004

[Problems to be Solved by the Invention] By the way, the trajectory of the transfer film passing between guide rollers B and B (hereinafter referred to as a path) in a state where no thermal transfer operation is being performed and a state where thermal transfer is being performed is as follows. If you look, transfer roll A
In the state shown by the solid line in FIG. 7 in which the transfer roll A is rising, the transfer film X is positioned approximately horizontally, whereas when the transfer roll A is descending, the transfer film X is pushed down. In particular, on the side of the transfer roll A, a pressing member C is installed so that the transfer film X is in surface contact with the circumferential surface of the workpiece W during thermal transfer. The transfer film X is pressed down more significantly by the pressing member C. Therefore, the path changes greatly between thermal transfer operations and during the thermal transfer operation.

In addition, the film feeding speed during thermal transfer is
It is not determined by the winding speed of the transfer film, but is actually determined by the rotational speed of the transfer roll A rotating in contact with the transfer film X. In thermal transfer, in order to perform high-quality painting, During thermal transfer operation,
When the transfer film X is released from the pressing pressure of the transfer roll A, the transfer film X does not immediately separate from the workpiece W, but the transfer film X is slightly attached to the circumferential surface of the workpiece W at the arrow d portion in FIG. desirable. Therefore, the work W
The transfer film X becomes slack in the portion where it passes through.

[0006] Because the transfer film X changes in its path and sag as described above, back tension is applied to the transfer film X on the film feeding side, and as the transfer roll A rises upon completion of thermal transfer, It is necessary to absorb the change and slack by pulling it back to the film feeding side.

However, in the conventional film feed control method in which the positioning mark M of the transfer film X is detected after the thermal transfer operation is completed and the winding of the transfer film X is stopped, when the transfer roll A starts to rise, the positioning mark M is detected. Since the film winding has not been stopped (that is, the positioning mark has not been detected), the motion in the direction of pulling back the path change and slack (arrow P in Fig. 7)
1) and the movement in the feeding direction (indicated by arrow P2 in FIG. 7) occur in combination, making the behavior of the transfer film X extremely unstable. Therefore, even if the above-mentioned positioning mark is detected and the feeding of the transfer film X is controlled when the behavior is unstable, precise control cannot be achieved, and the transfer film Therefore, it is necessary to detect the positioning mark M after this period of unstable behavior has elapsed, resulting in time loss, which impedes high-speed transfer and reduces the feed amount of the transfer film X. There was the inconvenience of adding more.

SUMMARY OF THE INVENTION An object of the present invention is to provide a film feed control method that does not cause the above-mentioned time loss or increase in film feed amount.

[0009]

[Means for Solving the Problems] That is, the invention according to claim 1 of the present invention (hereinafter referred to as the first invention) rotates a transfer film stretched across a film feeding side and a film winding side. Pressing the transfer film against the object to be transferred using a transfer roll, and winding up the transfer film at the time of the pressing to transfer the transfer layer formed on the transfer film to the object to be transferred, and stopping the winding of the transfer film. In the film feeding control method, the positioning is performed by detecting positioning marks formed at regular intervals on the transfer film, and the slack of the transfer film that occurs during the thermal transfer operation is absorbed by the back tension on the film feeding side. The present invention is characterized in that the mark is detected during the transfer operation in which the transfer roll is pressed against the object to be transferred.

[0010] Furthermore, the invention according to claim 2 (hereinafter referred to as the second
The present invention is characterized in that the positioning mark is detected during the thermal transfer operation, and the timing of each operation is set so that winding of the transfer film is stopped after the thermal transfer operation is completed.

Furthermore, the invention according to claim 3 (hereinafter referred to as the third invention) is such that the positioning mark is detected during the thermal transfer operation, and the winding of the transfer film is stopped after the thermal transfer operation is completed. It is characterized in that the time from mark detection to winding stop is controlled by a delay timer.

0012

[Operation] According to the first aspect of the present invention, the positioning marks on the transfer film are detected during the thermal transfer operation when the transfer roll is in contact with the object to be transferred via the transfer film. Even if the transfer film is pulled back by the back tension on the film feeding side when the transfer roll is raised upon completion of the thermal transfer operation, the transfer film can be controlled to be fed regardless of this movement.

By the way, as mentioned above, the path change and slack of the transfer film that occurs during the thermal transfer operation are absorbed by the back tension on the film feeding side after the thermal transfer operation, but depending on the thermal transfer conditions, Due to the return, the positioning mark once detected by the mark detection sensor may return to the film feeding side beyond the sensor, which may make film feeding control difficult. The second aspect of the present invention addresses this problem, and sets the timing of each operation so that winding of the transfer film is stopped after the thermal transfer operation. That is, even if a stop signal is input to the motor used for winding the film, the motor rotates with inertia for a certain period of time, so the film winding is not immediately stopped. Also, the above time varies depending on the type of motor. Furthermore, the thermal transfer time also changes depending on the thermal transfer conditions. Therefore, the timing of these operations is set so that the actual film winding stops after the thermal transfer is completed. According to this, in the movement of the transfer film after the thermal transfer operation, the return due to back tension and the feed due to winding overlap, and the amount of return is suppressed. Therefore, the positioning mark once detected will not be returned to the film feeding side beyond the mark detection sensor.

Furthermore, according to the third invention, since the film winding stop after the thermal transfer operation is completed is controlled using a delay timer, the time from mark detection to winding stop is controlled depending on the thermal transfer conditions. You can adjust it to the best one.

[0015]

Embodiments Next, embodiments of the present invention will be explained based on the drawings.

FIG. 1 shows a thermal transfer apparatus 1 to which the method of the present invention is applied.
The schematic configuration is shown below. That is, this thermal transfer device 1 is a device for painting the circumferential surface of a workpiece W having a cylindrical shape or a similar shape, and an endless chain 4 is wound around a pair of sprockets 3, 3 that are pivotally supported on a support plate 2. The workpieces W to W to be painted are held in a jig (not shown) attached to the endless chain 4 and are rotated by an inverter 6. By inputting the rotational force of the speed-controlled motor 7 via the brake device 8, the conveying means 5 is driven to convey the works W to W held in the jig in the direction of the arrow a. There is.

A transfer roll 9 is positioned above the conveyance means 5 so as to be movable up and down in the direction of arrow b in FIG. Film X is supplied. That is, the transfer film It is wound up on the winding shaft 12. In that case, the transfer film X is fed by rotating the film winding shaft 12 while applying back tension in the pulling direction to the transferred film X fed out on the film feed shaft 10 side. In addition, positioning marks M drawn at regular intervals on the transfer film X are detected in the film transport path from the film feed shaft 10 to the film take-up shaft 12 and on the film feed shaft 10 side rather than the transfer roll 9. Mark detection sensor 13
is provided.

Further, on the side of the transfer roll 9, in order to ensure that the transfer film X is adapted to the circumferential surface of the workpiece W during the thermal transfer operation when the transfer roll 9 is descending, the transfer film X is moved downward. A pressing member 14 for pressing is attached.

Further, a controller 15 shown in FIG. 3 is provided to control the thermal transfer apparatus 1 shown in FIG. 1, and a mark detection sensor 13 and a rotation angle sensor 16 are connected to the controller 15. An inverter 6 that performs speed control and a film winding device 17 that controls driving of the film winding shaft 12 described above are connected. In that case, the mark detection sensor 13 inputs a detection signal of the positioning mark M to the controller 15, and the controller 15 outputs a stop signal to the film winding device 17 based on the detection signal. is set to be performed while the transfer roll 9 is lowered and comes into contact with the workpiece W via the transfer film X to perform a thermal transfer operation. On the other hand, the transport means 5 for the workpiece W
has a cam mechanism (not shown) that is interlocked with the brake device 8 by a rotational force transmission means 18 and is driven by the rotational force input from the rotational force transmission means 18,
The cam mechanism is configured to drive the conveyance means 5 and the elevating means for the transfer roll 9 synchronously, and the rotation angle sensor 16 detects the rotation angle in the cam mechanism and inputs it to the controller 15. The controller 15 is configured to read the top dead center, bottom dead center, etc. of the transfer roll 9, and to control the rotational speed of the motor 7 by the inverter 6.

Next, the film feed control operation will be explained with reference to the flowchart of FIG. 4. The workpiece W is carried directly below the transfer roll 9 located at the top dead center position (solid line position) in FIG. Accordingly, the controller 15 outputs a thermal transfer start signal. As a result, in step S1, the transfer roll 9 is lowered, and the thermal transfer operation is started at the bottom dead center of step S2, where the transfer roll 9 contacts the workpiece W via the transfer film X, and following this, in step S3 The film winding device 17 is driven, and the transfer film X is wound around the film winding shaft 12. Then, by keeping the contact state of the transfer roll 9 for a predetermined time, the workpiece W is rotated by the rotational force of the transfer roll 9, and during that time, the transfer layer of the transfer film X is rotated by the pressing pressure and heat of the transfer roll 9. The image is transferred and painted onto the circumferential surface of the workpiece W. During the thermal transfer, the transfer film The feeding speed of the film X is determined by the rotational speed of the transfer roll 9 in the portion where thermal transfer is performed. Then, during a thermal transfer operation in which the transfer roll 9 is in contact with the workpiece W via the transfer film X, the positioning mark M drawn on the transfer film X is detected by the mark detection sensor 13 in step S4, and the positioning mark M drawn on the transfer film X is detected in step S5. Upon completion of the thermal transfer operation, winding of the transfer film X is stopped in step S6, and the transfer roll 9 starts to rise. As a result, the feeding of the transfer film X is stopped almost simultaneously with the completion of thermal transfer, and during the thermal transfer operation, the pressing member 1
4 pushes the transfer film X downward between the guide rollers 11 and 11, a change in path occurs, and the transfer film X slightly adheres to the circumferential surface of the workpiece W, causing some slack on the downstream side in the film feeding direction. occurs in Therefore, when the thermal transfer operation is completed and the transfer roll 9 is raised, the transfer film X is pulled back in the direction of arrow P1 in FIG. Become.

However, in the present invention, as described above, the positioning marks on the transfer film X are detected during the thermal transfer operation.
Even if unstable behavior occurs, the positioning mark can be detected at a point unrelated to this. Furthermore, during thermal transfer, the transfer film X is fed at a constant speed by the rotational force of the transfer roll 9 as described above, so that the above detection can be performed stably and accurately. Therefore, the time interval of the thermal transfer operation can be determined while ignoring the time during which the transfer film X exhibits unstable behavior, and by shortening the time interval, high-speed transfer is possible, and one thermal transfer cycle The feeding amount of the transfer film X can be shortened, and the waste of the transfer film X can be eliminated.

By the way, as mentioned above, the positioning mark M
By performing the detection during the thermal transfer operation, film control can be performed regardless of the behavior of the transfer film When considering the amount of return of the transfer film X due to the back tension, depending on the thermal transfer conditions, the mark detection sensor 1 may
The positioning mark M detected by 3 is the film feeding shaft 1.
A situation may occur in which the film returns to the 0 side beyond the sensor 13, and the positioning mark M will be detected again during the next film feed, which may make film feed control difficult.

Therefore, in the second embodiment of the present invention, FIG.
As shown in the flowchart, mark detection is performed during the thermal transfer operation in step S14, and then, after the thermal transfer operation is completed in step S15 and the transfer roll 9 starts to rise in step S16,
The timing of each operation is set so that film winding is stopped in step S17 (note that step S1
1 to S13 are the same operations as steps S1 to S3 in FIG. 4). This timing is set in accordance with the thermal transfer time, the characteristics of the motor used in the film winding device 17, and the like. For example, when the mark detection sensor 13 detects the positioning mark M and inputs a detection signal to the controller 15, and the controller 15 outputs a stop signal to the film winding device 17, the above motor will not operate even if the stop signal is input. Since it rotates due to inertia, it takes some time for it to actually stop, and this time varies depending on the type of motor selected, so it depends on the time it takes for film winding to actually stop from mark detection and the thermal transfer operation. In relation to the time required for this, the timing is set so that the film winding is stopped after the transfer roll 9 starts rising upon completion of the thermal transfer operation.

According to this, when the transfer film X returns due to back tension, the return direction P1
Since the film is fed in the opposite direction, the amount of return can be kept small, and a situation in which the detected positioning mark M returns beyond the mark detection sensor 13 can be avoided. Therefore, film feed control is not hindered.

Furthermore, when the film winding is stopped after the thermal transfer operation is completed as described above, it is important that the mark detection sensor 13 reliably detects the next positioning mark M in a timely manner during the next thermal transfer operation. Yes, but
As described above, if the thermal transfer conditions change, the above-mentioned timing also changes, and it is conceivable that the detection time of the positioning mark M may be shifted.

FIG. 6 shows a control circuit of a third embodiment that deals with such a problem.
9 is built in, and by setting a delay time using this delay timer 19, the film winding device 17 is stopped when the above-mentioned delay time has elapsed from the time when the mark detection sensor 13 detects the mark. According to this, by adjusting the delay time according to the thermal transfer conditions, it is possible to adjust the mark detection sensor 13 to detect marks in a timely manner during the thermal transfer operation.

[0027]

Effects of the Invention As is clear from the above description, according to the first aspect of the present invention, the positioning mark detection on the transfer film is performed by a thermal transfer operation in which the transfer roll is in contact with the object to be transferred via the transfer film. Go inside and stop feeding the transfer film. Therefore, even if the transfer film is pulled back by the back tension on the film feeding side when the transfer roll rises due to the completion of the thermal transfer operation, the transfer film can be controlled regardless of this, and the transfer film can be fed at high speed by shortening the transfer film feeding time. Not only can the transfer be performed, but also the waste of the transfer film can be eliminated.

Further, in the second invention, while mark detection is performed during the thermal transfer operation, the timing is set so that the actual film winding stops after the completion of the thermal transfer.
The amount of return due to back tension of the transfer film is reduced. Therefore, the positioning mark once detected by the mark detection sensor is not pulled back beyond the sensor, and stable film control can be performed.

Furthermore, in the third aspect of the invention, since the time point at which the film winding is stopped after the thermal transfer is completed is adjusted by a delay timer, even if the thermal transfer conditions change, the mark can be reliably detected during the thermal transfer operation. Good film control can be achieved even under various thermal transfer conditions.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a thermal transfer apparatus to which the method of the present invention is applied.

FIG. 2 is an explanatory diagram of the method of the present invention.

FIG. 3 is a control circuit diagram of the device in FIG. 1.

FIG. 4 is a flowchart diagram illustrating control operations.

FIG. 5 is a flowchart diagram of the second embodiment.

FIG. 6 is a control circuit diagram of the third embodiment.

FIG. 7 is an explanatory diagram of a conventional control method.

[Explanation of symbols]

1 Thermal transfer device 9 Transfer roll 13 Mark detection sensor 19 Delay timer M Positioning mark W Work X Transfer film

Claims (3)

[Claims] Claim 1: A transfer film stretched across a film feeding side and a film winding side is pressed onto an object to be transferred by a rotating transfer roll, and
At the time of the pressing, the transfer film is wound up to transfer the transfer layer formed on the transfer film to the object to be transferred,
In addition, the winding of the transfer film is stopped by detecting positioning marks formed at regular intervals on the transfer film, and the slack of the transfer film that occurs during the thermal transfer operation is absorbed by the back tension on the film feeding side. 1. A film transport control method, characterized in that the positioning mark is detected during a transfer operation in which a transfer roll is pressed against an object to be transferred. [Claim 2] A transfer film stretched across a film feeding side and a film winding side is pressed onto an object to be transferred by a rotating transfer roll, and
At the time of the pressing, the transfer film is wound up to transfer the transfer layer formed on the transfer film to the object to be transferred,
In addition, the winding of the transfer film is stopped by detecting positioning marks formed at regular intervals on the transfer film, and the slack of the transfer film generated during the thermal transfer operation is absorbed by the back tension on the film feeding side. The film feeding control method includes detecting the positioning mark during the transfer operation in which the transfer roll is pressed against the transferred object, and detecting the positioning mark during each operation so that the winding is stopped after the thermal transfer operation is completed. A film advance control method characterized by setting timing. 3. A transfer film stretched across a film feeding side and a film winding side is pressed onto an object to be transferred by a rotating transfer roll, and
At the time of the pressing, the transfer film is wound up to transfer the transfer layer formed on the transfer film to the object to be transferred,
In addition, the winding of the transfer film is stopped by detecting positioning marks formed on the transfer film at regular intervals, and the slack of the transfer film that occurs during the thermal transfer operation is absorbed by the back tension on the film feeding side. A film feeding control method that detects the positioning mark during the transfer operation when the transfer roll is pressed against the transfer target, and detects the mark so that the winding stop is performed after the thermal transfer operation is completed. A film advance control method characterized in that the time from start to stop of winding is controlled by a delay timer.