JPS5820470A - Thermal transfer recorder - Google Patents

Abstract

PURPOSE:To maintain the load applied on a driving motor approx. constant by varying the braking force of a donor feeding roll or the torque to a donor winding roll according to the changes in the diameter thereof being detected. CONSTITUTION:As soon as the delivery of a recording paper 7 starts with a start button pressed ON, the load adjustment of a driving motor 8 is started. A variable resistor 26 detects change in the diameter of a feed roll 2 which is inputted into a load signal generator 32 after an analog-digital conversion. From an address corresponding to the inputs, load signals are read out corresponding to the load to be corrected and inputted into an electromagnetic brake driving circuit 34 after a digital-analog conversion to set a current value for an electromagnetic brake 27 so that the load of the driving motor 8 can be maintained at a fixed value. Otherwise, the load can be controlled with a clutch on the side of a winding roll 6. This permits the correction of changes in the load only depending on changes in the diameter of an arbitrary roll thereby simplifying the equipment and reducing the size thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording device equipped with a mechanism for adjusting the tension of an ink donor sheet.

In a thermal transfer recording device, an ink donor sheet coated with thermally transferable (thermal melting or thermal sublimation) ink and recording paper are overlapped, and heat is selectively supplied from the ink donor sheet l- side. Information is recorded by transferring the ink melted or sublimated in a bath onto recording paper.

By the way, in a thermal transfer recording device that records on cut recording paper, (i) an ink donor sheet of the same size as the SA recording paper is prepared in advance and superimposed on all the recording paper, and this is sequentially supplied to the recording section. and one in which recording is performed by
(fl) There is a method in which a long ink donor sheet is continuously supplied to 1ii12 recording locations using a donor supply roll.

Compared to the former, the latter type of device has the advantage of: - In addition to the lower running cost of the ink donor sheet, - For example, the recording paper can follow the path of the ink donor sheet after passing through the recording section. By using a method such as changing the ink donor sheet suddenly to the extent that it does not occur, it is possible to first mechanically separate the ink donor sheet from the recording paper sheet. There is an advantage that the inconvenience of 1- is eliminated.

However, in the latter device using a donor supply roll, since the ink donor sheet 1-k is conveyed alone, wrinkles may occur in the ink donor sheet 1-k, which may cause a situation where thermal transfer recording becomes partially ineffective. Ta. In other words, since the ink donor sheet from the point of view of thermal transfer efficiency is made very thin, if the tension becomes uneven, undulations may occur on the optical surface of the sheet, and in this state, the ink donor sheet When pressed against a thermal head for heat-sensitive recording, wrinkles may occur, which may impede ink transfer.

FIG. 1 shows a thermal transfer recording device proposed to eliminate these drawbacks. In this device, the entire ink-doped sheet 1 is fed out from the donor supply roll 2 in the same way as in the conventional device, and the ink doped sheet 1 is fed out from the donor supply roll 2, and the ink-doped sheet 1 is fed out between the thermal head 3 and the back roller 4 (recording section), and between the back roller 1 and the drive roller 5. 1, conveyance of the ink donor sheet 1, which is to be wound up on the donor take-up roll 6 after passing j1φ (r, 1+:, contacting dry blow for 25 seconds), and the donor take-up roll 6 When the recording operation is started, the recording paper 7 is supplied to the lower part of the back roller 4 from a recording paper supply tray (not shown).

At this point, the driving motor 8 starts to transport the ink donor /-1; at 1l-1p, the self-recording paper 7 passes between the thermal head 3 and the back roller 4 together with the ink donor sheet 1. do. At this time, thermal transfer recording is performed. When the recorded recording paper passes between the back roller 4 and the drive roller 5, it is peeled off from the ink donor sheet 1 and is discharged to a discharge tray (not shown).

By the way, in this proposed device, the donor supply roll 2
A brake mechanism 12 is attached to the rotating shaft 11 of the ink donor sheet to apply back tension to the ink donor sheet. Further, a drive shaft 14 is connected to the rotating shaft of the donor take-up roll 6 via a slip clutch 13.1. During the rotation of the drive shaft 14 and drive roller 5, the torque of the drive motor 8 is transmitted by the bells 1 and 16, so that the torque delivered to the donor take-up row/roller 6 can be adjusted by i rotations. The ink donor sheet 1 was adjusted to prevent it from being rolled up with excessive tension.

By the way, as shown in FIG. 2, the respective load curves 17 due to the inertia of the donor supply roll 2 and the donor take-up roll 6.
18 is expressed as a function of the square of the radius of each roll. On the other hand, the load curve 19 caused by the brake mechanism 12 is proportional to the roll radius, and the slip clutch 13
The load curve 21 becomes a constant value. Therefore, although the tension of the ink donor sheet 1 is adjusted according to the proposed device, as shown by the load curve 22 representing the load variation of the drive motor 8, the tension of the drive motor 8 due to the use of the ink donor sheet 1 is There was a noticeable load fluctuation. Therefore, in this proposed device, the ink donor sheet 1 and the recording paper 7 could not be stably run in the sub-scanning direction, and there was a problem that the image quality was adversely affected. .

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a thermal transfer recording device that can keep the load applied to the drive motor substantially constant.

In the present invention, the diameter of the donor supply roll or the donor take-up roll is detected, and the braking force of the donor supply roll or the i
・Achieve the above objectives by changing the

The present invention will be described in detail with reference to Examples below.

FIG. 3, in which the same parts as in FIG. 1 are denoted by the same reference numerals, shows a thermal transfer recording apparatus in which the load is adjusted on the donor supply roll side. The end of a shear actuator 25 is in light contact with the outer periphery of the donor supply roll 2 of this device by means of a compression spring 24. The other end of the actuator 25 is fixed to a rotating shaft 26A of a variable resistor 26 fixed on a stationary member (not shown). An electromagnetic brake 27 is attached to the rotating shaft of the donor supply roll 20.

FIG. 4 shows the arrangement relationship between the donor supply roll and the electromagnetic brake. A movable iron core 27A of an electromagnetic brake 27 is housed at the -y height of the rotating shaft 11 of the donor supply roll 2. Asbestos &27B, which has excellent heat resistance and wear resistance, is pasted on the end face of the movable iron core 27A. The joint plate 27C of the DC electromagnet of the electromagnetic brake 27 is
A tension spring 29 completely fixed at one end to the frame 2 and 3 of the device.
It is arranged so that it can move a certain distance in the axial direction of the rotating shaft 11, and there is a slight gap between it and the asbestos plate 27'B when the electromagnetic brake 27 is not operating.

Now, when a start button (not shown) for starting a recording operation is pressed in this thermal transfer recording apparatus, feeding of recording paper 7 from a recording paper supply tray (also not shown) is started.

At the same time, load adjustment of the first drive motor 8 starts.

FIG. 5 shows a circuit configuration for load adjustment. The variable resistor 26 exhibits a resistance value that corresponds to a change in the rotation angle 1' of the actuator, that is, a change in the diameter of the donor supply roll 2. At the start of the recording operation, this resistance value is converted into a current value or voltage value and input to the AD converter 31. A
-D converter 31 converts this into a digital signal and supplies it to load signal generator: 32. The load signal generator 32 is RO
M (read-only memory) is built in, and the supplementary 1 memory is stored at the address corresponding to the supplied digital signal.
■Is the load signal equivalent to the load that should be applied? 11-Read.

FIG. 6 is for explaining the contents of the load signal stored in ROi■. As already explained in FIG. 2, the load curves 17, 18 of the donor supply roll 2 and the donor take-up roll 6 are expressed as a function of the square of the roll radius, and the load curve 21 due to the slip clutch 13 is a constant value. becomes. Therefore, the load curve representing the sum of each load in the apparatus of this embodiment becomes a quadratic curve as shown in the figure.

The maximum value of this load curve 36 is assumed to be f F max . In order to prevent wrinkles from occurring in the ink donor sheet 1 during running, it is necessary that the electromagnetic brake 27 has a certain amount of braking 1q during the running. Therefore, the load curve 37 for setting the negative +-r ffi applied to the drive motor 8 becomes a constant value FA that is somewhat larger than the maximum value Fmax of the load curve 36. In this case, the donor take-up roll 2
The difference F between the load curve 37 and the load curve 36 at each radius VC of
B is the content (digital detail) of each load signal stored in /l in R01.

Similar load signals are stored in the ROM for all types of replacement donor supply rolls available for use with the machine, and are sent to the load signal generator 32 when the machine operator replaces the donor supply roll 2. When all the provided switches (not shown) are selected, a load signal corresponding to a change in the diameter of the replaced donor supply roll 2 is read out from the ROM.

The load signal read out in this manner is converted into an analog signal by the 1-A converter 33 and then supplied to the electric brake drive circuit 34. Electromagnetic brake, 1g
The dynamic circuit 34 amplifies the analog signal, sets the current value supplied to the electromagnetic brake 27, and maintains the load on the drive motor 8 at a constant value FA.

As described above, according to the present invention, since fluctuations in the load applied to the +g drive motor are corrected by the donor 11 (feed roll shunting/ner take-up roll alone), for example, a device for attaching a mechanism for load correction to both rolls is used. Compared to this, the device can be manufactured in a smaller size and at a lower cost.

In addition, in the actual example, an electromagnetic brake was used to adjust the load, but for example, like a powder brake, the input voltage or t
d. Of course, any component that can vary the braking force depending on the input current can be applied. The same applies to the case where the negative 1di is controlled by the clutch of the toner collecting roll 10].

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventionally proposed thermal transfer recording device.
Fig. 2 is a characteristic diagram showing the relationship between the radius of the donor supply roll and the load change of each component in this device, and Figs. 3 to 5 are for explaining one embodiment of the present invention. 3
The figure is a schematic configuration diagram of the thermal transfer recording device, Figure 4 is a sectional view showing the electromagnetic brake attached to the donor supply roll, Figure 5 (d) is a block diagram of the load 1A distortion circuit, and Figure 6 is the donor supply port. 1 is a characteristic diagram showing the relationship between the radius of the roller and the load change of each component. 1. Ink donor sheet 2. Donor supply roll 3. Thermal head 4. Back roll 6. Donor take-up roll 7 ・・・・・・1 Self-registration test ・ 8・・・・1 Drive motor 25 ・・Actuator 26・・Variable resistor 27・・・Electromagnetic brake 32・・・Load signal generator Applicant Fuji Serotox Co., Ltd. Representative Patent Attorney Umeo Yamauchi = 11-1

Claims (1)

[Claims] The ink donor sheet coated with thermally transferable ink is selectively heated to the donor supply roll, which is entirely wound into a roll, and the ink donor sheet fed out from the donor supply roll. A recording section that performs transfer, a donor take-up roll that collects the used ink donor sheet that has passed through the recording section, a detection means that detects the diameter of the donor supply roll or the donor take-up roll, and a detection means that detects the rotation of the donor supply roll. A braking means for braking, a torque adjusting means for adjusting the torque transmitted to the donor take-up roll, a power source for conveying the ink donor sheet, and a power source for controlling the power source in response to the detection result of the detecting means. A thermal transfer recording apparatus characterized by comprising: load adjustment means for adjusting the braking force or torque of the braking means or torque adjustment means so that the load is approximately constant.