JPS6018364A - Transfer type thermal recording apparatus - Google Patents

Abstract

PURPOSE:To obtain a multi-color image free from color shift by maintaining high speed capacity, by detecting the running state of a detection sheet running in synchronous relation to recording paper to compare the detected value with the objective value of the running state of the recording paper while controlling the driving of an ink donor film corresponding to the compared value. CONSTITUTION:A stepping motor 20 is driven by the pulse output from a pulse oscillator 25 from a motor driving circuit 21 corresponding to a drive order 26. At this time, said pulse is also output to a pulse counter 22 to store the amount of rotation of the stepping motor 20. A drive roller 5 is driven by the rotation of the stepping motor 20 to convey an ink donor film 4 and recording paper 1 and a detection sheet 10 are conveyed with the advance of said film 4. In this state, a detection roller 7 is revolved and the amount of revolution thereof is transmitted to a rotary encoder 9 while the output of said encoder 9 is supplied to calculator 23 to calculate the number of pulses imparted to the stepping motor 20. Subsequently, pulses corresponding to an objective value are output from the motor driving circuit 21 by a comparator 24 to control the stepping motor 20.

Description

[Detailed Description of the Invention] (Field of Application) The present invention relates to a transfer type thermal recording device.
In particular, the present invention relates to a transfer type thermal recording device with improved color resist.

(Prior art) As one method for realizing multicolor recording using transfer type thermal recording technology, as shown in FIG. It is known to use ink donors of different colors applied in a sequential and periodic manner, and to sequentially perform recording with a negative set of recording head sections.

FIG. 2 is a schematic diagram of the transfer type thermal recording apparatus in this case.

The recording paper 1 is placed between the back roller 2 and the thermal head 3.
and ink donor film 4 are fed in a superimposed manner. The ink donor film 4 is supplied from an ink donor film supply roller 13 and taken up by an ink donor film take-up roller 14 .

An image signal corresponding to one color tone (yellow Y, cyan C, or magenta M) corresponding to the ink donor film 4 is supplied to the thermal head 3, so that print recording is performed in the corresponding color tone.

After printing in the first color is completed, for example, by separating the back roller 2 from the thermal head 3 and rotating it in reverse (rotating in one direction in the example shown), the recording paper 1 is moved to the recording start position. Then, print in the second color in the same way as above, and then print in the third color in exactly the same way.
Performs color print recording.

In this way, yellow Y1 cyan C1 magenta M
A three-color image is obtained.

However, with this method, (1) recording takes a long time because the recording paper 1 is conveyed in the opposite direction; (2) a special ink donor film 4 as shown in FIG. 1 is used; Not only does this increase the cost of recording, but it also has the disadvantage that it is difficult to use for monochrome recording.

In order to overcome these drawbacks, a transfer type thermal recording apparatus has been proposed which is provided with three independent recording head sections for each color, as shown in FIG. In this figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

Note that the subscripts Y, M, and C indicate that the respective parts or parts are for yellow (Y), cyan (C), and magenta (M), and the dotted lines indicate the transport path of recording paper 1. It's raining.

In the transfer-type thermal recording apparatus shown in FIG. 3, there is no need to transport the recording paper 1 in the reverse direction, and since the ink donor film 4 is for monochrome use, as described above with respect to FIGS. 1 and 2, These drawbacks can be improved, and a transfer-type thermal recording device capable of high-speed recording and relatively low cost can be realized.

However, in this case, since the maximum feed or feed speed of the recording paper 1 in each recording head section is controlled independently, the recording start point at a5 is accurately synchronized in each thermal head section. Even in this case, there is a drawback that if there are variations in the feed rate or the feed speed, color shift is likely to occur in the recorded image, making it difficult to realize color registration with high precision.

Further, as a method for detecting the feed amount or feed speed of the recording paper 1, a rotary encoder or the like is installed directly on the back roller 2, and the rotation of the recording paper 1 is detected as representing the movement of the recording paper 1. I can think of it.

However, the pressure and rubber hardness of the back roller 2 are limited in order to maintain good quality of recorded images, and the pack tension and pressure are also limited in terms of rubber deformation, load, etc. Detecting the movement of the recording paper 1 by the rotation of the back roller 2 is not sufficient because it is not only impossible to remove the slip between the paper 1 and the recording paper 1, but also the hardness of the rubber may change due to changes over time. Accuracy could not be obtained.

(Objective) The present invention has been made to eliminate the above-mentioned drawbacks, and its object is to maintain high-speed recording performance while maintaining high-speed recording performance.
Moreover, the object of the present invention is to develop a transfer-type thermal recording device that can realize a highly accurate color regime.

(Overview) In order to achieve the above object, the present invention interposes a detection sheet between the recording paper and the back roller, which is driven in synchronization with the recording paper and detects the feed Φ or the feed speed. , is characterized in that it is configured to accurately measure the feeding speed or feeding speed of the detection sheet.

<Example) The present invention will be described in detail below with reference to the drawings.

FIG. 4 is a side view showing essential parts of an embodiment of the present invention.

In this figure, the same reference numerals as in FIG. 2 represent the same or equivalent parts.

d'3, Figure 4 shows the structure of only the recording head section for one color in Figure 3, but the transfer type thermal recording device of the present invention has a similar recording head section for each color independently. It is natural that there are several.

In addition to the recording paper 1 and the ink donor film 4, a detection sheet 10 is further superimposed and fed between the back roller 2 and the thermal head 3.

It is preferable that the detection sheet 10 has an endless configuration as shown in the figure, and it is necessary that the detection sheet 10 does not slip between it and the recording paper 1 when used monthly. As the detection sheet 10, for example, a glass fiber cord coated with a rubber material is suitable.

A pinch roller 6 is pressed against the drive roller 5 with a predetermined pressure so as to sandwich the ink donor film 4 therebetween. Further, a pressure roller 8 is pressed against the detection roller 7 with a predetermined pressure so as to sandwich the detection sheet 10 therebetween.

The rotary encoder 9 is mechanically connected to the detection roller 7 and outputs a signal representing the amount of rotation thereof.

During the recording operation, for example, by a stepping motor,
When the drive roller 5 is driven, the ink donor film 4 is conveyed to the left, and at the same time, the recording paper 1 and the detection sheet 10 are also conveyed to the left.

On the other hand, since image signals are supplied to the thermal head 3 by a known appropriate method, the ink donor film 4
The selective heating and melting of the second ink layer and the transfer of the melted ink to the recording paper 1 are carried out.

In this way, a desired image is recorded on the recording paper 1.

During the recording operation described above, the detection sheet 10 is driven in the direction of the arrow in the figure at a speed that completely matches the conveyance speed of the recording paper 1. As the detection sheet 10 is driven, the detection roller 7 and the pressure roller 8 are rotated.

The rotation amount of the detection row 57 is converted into an electric signal by the rotary encoder 9, and based on this, the -
Therefore, the feed base or feed speed of the recording paper 1 is detected.

Next, referring to FIG. 5, a recording paper 1 suitable for the present invention will be described.
The general structure and operation of the dovetail lifting or feed rate detection and control device will be explained. In addition, in the figure, the same reference numerals as in FIG. 4 refer to the same or equivalent parts.

The stepping motor 20 is driven by output pulses from a motor drive circuit 21, which are obtained by controlling drive pulses generated by a pulse oscillator 25 in accordance with a drive command 26.

The output pulses from the motor drive circuit 21 are also supplied to a pulse counter 22 and counted there. Therefore, the pulse counter 22 includes the stepping motor 20
The amount of rotation will be stored.

On the other hand, as is clear from the explanation related to FIG. It is transported in the same way.

Then, the detection roller 7 is rotated by the detection sheet 10, and the amount of rotation is transmitted to the rotary encoder 9.

Here, the recording paper 1, the detection sheet 10, the detection roller 7, and the rotary encoder 9 can be configured so that there is virtually no slip or play between them.
The output change m of the rotary encoder 9 can be seen as representing the actual feeding amount of the recording paper 1.

The output of the rotary encoder 9 is supplied to a calculator 23, where the actual feed ω of the recording paper 1 is converted into a pulse value to be supplied to the stepping motor 20 assuming that there is no slip or rattle. Ru.

In other words, the calculator 23 calculates the number of pulses to be applied to the stepping motor 2° in order to convey the recording paper 1 by a distance corresponding to the amount of change in the output of the rotary encoder 9.

The outputs of the pulse counter 22 and the arithmetic unit 23 are supplied to a comparator 24 and compared.

As is clear from the above explanation, the output of the comparator is O-
That is, the fact that the outputs of the arithmetic unit 23 and the comparator 24 are equal means that the amount of rotation of the stepping motor 2° is transmitted to the recording paper 1 without slipping.

Furthermore, if the output of the arithmetic unit 23 is smaller than the output of the pulse counter 22, a slip occurs between the stepping motor 20, the drive roller 5, the ink donor film 4, and the recording paper 1, causing the rotation of the stepping motor 2o. This means that the amount is not completely transferred to the recording paper 1.

That is, in the latter case, the amount of feed of the recording paper 1 will be less than the set value. Therefore, in the present invention,
In such a case, a number of pulses corresponding to the output of the comparator 24 are additionally supplied from the motor drive circuit 21 to the stepping motor 20 to drive it, thereby supplementing the feed amount of the recording paper 1. -I try to do it.

In addition, when supplying additional pulses to the stepping motor 20 as described above, either clear the outputs of the pulse counter 22 and the arithmetic unit 23, or subtract the count value of the pulse counter 22 by the amount of the additional pulses, or It is necessary to add an additional pulse to the output of the arithmetic unit 23 to return the comparator 24 to an equilibrium state.

In the above manner, the maximum feed of the recording paper 1 can be accurately matched to the set value, so similar feed amount control can be performed for the recording head sections for each color tone, and the pulse oscillator 25 can be shared. If J5 is used, it is possible to accurately match the feeding amount of the recording paper 1 for each reliable recording head section, and it is possible to realize highly accurate color registration.

Moreover, if the above-mentioned feed rate control is performed in an extremely short period, the feed speeds can be matched, and color registration with even higher precision can be achieved.

FIG. 6 is a schematic block diagram showing another example of a detection and control device for the feed amount or feed speed of the recording paper 1 suitable for the present invention. In the figure, the same reference numerals as in FIG. 5-C1 represent the same or equivalent parts.

As is clear from the comparison with FIG. 5, in this example, the pulse counter 22 of FIG. 5 is replaced with a function generator 28, and the function generator 28 is activated by the drive command 26.

The function generator 28 uses the elapsed time from the start of recording as a parameter to generate an electric signal representing the number of pulses to be supplied to the stepping motor 20 at that time (therefore, the amount of feed of the recording paper 1).

That is, the output of the function generator 28 corresponds to the target value along the feed of the recording paper 1, while the output of the arithmetic unit 23 corresponds to the fifth value.
As explained with reference to the figures, this shows the actual feeding of the recording paper 1.

Therefore, as is clear, the comparison between the two is performed using the comparator 24.
If this is done and the motor drive circuit 21 is controlled according to the result, the actual feeding position of the recording paper 1 will be equal to the target value.

Therefore, if the function generator 28 is set equally for each color tone recording head section, a multicolor image with no color shift and extremely high color registration accuracy can be obtained.

Note that the present invention can be implemented with the following modifications.

(1) The detection sheet 10 is not endless but is shaped like a long and thin film.

(2) A detection slit is formed in the detection sheet 10, and the amount of movement thereof is detected by a light source and a light detection means.

(3) A magnetic mark is formed on the surface of the detection sheet 10, and the amount of movement thereof is detected by an appropriate magnetic detection means.

(Effects) As is clear from the above description, the following effects can be achieved according to the present invention.

(1) Since the feeding amount or feeding speed of the recording paper can be accurately detected and controlled for each recording head group for each color tone, a multicolor image without color shift can be obtained.

(2) Since the conventional configuration and recording method shown in FIG. 3 can be applied as is, a high recording speed can be maintained.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams showing the configuration of an ink donor film and a transfer-type thermal recording device for performing multicolor recording with a single thermal head, respectively, and Figure 3 is a schematic diagram showing the configuration of an ink donor film and a transfer type thermal recording device that uses multiple sets of recording heads. FIG. 4 is a side view showing a main part of an embodiment of the present invention, and FIGS. FIG. 5 is a schematic block diagram of a suitable recording paper feed or feed speed detection J5 and a control device. 1... Recording paper, 2... Back roller, 3... Thermal head, 4... Ink donor film, 5...
- Drive roller, 6... Binge roller, 7... Detection roller, 8... Pressure V-roller, 9... Rotary encoder, 10... Detection sheet, 20...
Stepping motor, 21... Motor drive circuit, 22
...Pulse counter, 23... Arithmetic unit, 24...
Comparator, 25...Pulse oscillator, 26 River drive command, 2
8...Function generator representative patent attorney Michito Hiraki and 1 other person

Claims (1)

[Claims] (1) A plurality of sets each consisting of a thermal head, a back roller press-contacted to the thermal head so as to sandwich a recording paper and an ink donor film, and means for driving the ink donor film, and arranged in series with each other. In a transfer type thermal recording device having a recording head section and means for feeding the recording paper between the back roller of each recording head section and the thermal head, overlapping the ink donor film, the recording paper is overlapped with the recording paper. Additionally, a detection sheet is fed between the back roller and the thermal head and is fed in synchronization with the recording paper, a means for detecting the running state of the detection sheet, and an output of the detection means for detecting the running state of the recording paper. 1. A transfer type thermal recording apparatus, comprising: means for comparing a running state with a target value; and means for controlling a driving means for the ink donor film in accordance with an output of the comparing means.