JP2572857Y2 - Thermal transfer type multi-color printing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal transfer type multicolor printing apparatus, and more particularly, to a thermal transfer type multicolor printing apparatus which corrects dot crushing at the time of surface printing.

[Conventional technology]

As is known, in order to obtain multiple colors by thermal transfer printing, various means such as an area gradation method and a dither method have been devised and put to practical use.

For example, as shown in FIG. 3, when performing area gradation with a 2 × 2 matrix, the number of dots from n = 1 to 4 can be selected, and four gradations can be realized.

Here, assuming that the transfer area per dot is S, the total transfer area ΣS at each n is as follows: n = 1 ΣS = S n = 2 ΣS = 2 × S + ΔS ₂ n = 3 ΣS = 3 × S + ΔS _{3 When} n = 4 ΔS = 4 × S + ΔS ₄

ΔS ₂ , ΔS ₃ , and ΔS ₄ are inks that are transferred when adjacent dots are transferred.

If ΔS ₂ , ΔS ₃ and ΔS ₄ are not transcribed concomitantly,
The total transfer area ΔS linearly increases in proportion to the number n of dots as indicated by a circle, and a good gradation can be obtained. However, in order to prevent adjacent dots from sticking to each other, it is necessary to reduce the size of the heating resistor of the TPH and increase the distance between the resistors, but it is not possible to print a line drawing Close to.

In the current apparatus, since a line drawing is mainly used, the total transfer area ΔS increases in proportion to the number n of dots as indicated by a mark ●.

It should be noted here that when the relational expression of ΔS ₂ <ΔS ₃ <ΔS ₄ holds, and the number of adjacent dots increases,
That is, the transfer area is extremely increased, and a linear gradation cannot be obtained.

This is remarkable when, for example, an attempt is made to realize 64 gradations in an 8 × 8 matrix. When a certain level is exceeded, most dots are crushed, which is the same as solid printing.

For this reason, even if the print data has a linear gradation gradient, the dots are crushed in the middle of the actual printing, and a good surface image cannot be obtained.

[Means for solving the problem]

In order to solve the above problems, a thermal transfer type multicolor printing apparatus of the present invention includes a memory for storing image data input from the outside, a print correction unit for controlling print data read from the memory, and a printing device. A thermal head driven by a signal based on the output data of the correction means. In the case of face printing in which the gradation is obtained by the area of the printed dot, the print correction means converts the print data of the odd-numbered dot or the even-numbered version dot into non-printing data for each line in the sub-scanning direction. The replacement operation is sequentially and alternately performed.
Then, when performing line drawing printing in another printing mode, the printing data is passed as it is.

[Action]

In the case of face printing, the resolution is
Although it falls to 1/2, in the main scanning and sub-scanning directions,
Since there are no adjacent print dots, the dots are less crushed and a good surface image can be obtained.

In the case of line drawing printing having a printing mode other than area gradation,
Since all print data is used, a good print result can be obtained without lowering the resolution.

〔Example〕

FIG. 1 is an embodiment of the present invention, and FIG. 2 is a timing diagram thereof.

Hereinafter, the present invention will be described with reference to the drawings. As is well known, a thermal transfer type multicolor printing apparatus inputs image data from a user interface circuit (not shown),
The data is temporarily stored in a memory, read out while synchronizing with the printing cycle, and transferred to the TPH to obtain printing.

In FIG. 1, a signal a is an input signal to a selector b and is print data read from a memory. Signal c
Is a clear signal to the flip-flop d, which is true when printing a face image.

The signal e is a select signal to the selector f, and the signal g is an output signal from the selector f and a select signal to the selector b. The signal h is an input clock to the flip-flop d and a data transfer clock to the TPH. The signal i is an output signal from the selector b, and the input signal a or the GND is selected depending on the state of the select signal g.

When the signal g is a low status signal, the signal a is selected by the selector b and transferred to the TPH as the signal i.

When the signal c becomes High, the flip-flop d performs a toggle operation at the rising edge of the signal h. The signal e is a status signal. High is input when the sub-scanning direction is an even line, and low when the odd scanning line is an odd line. Here, a case where the sub-scanning direction is an odd line will be described as an example.

The signal c changes from low to high, and the circuit becomes operable. At this time, the signal h is not input, and the flip-flop d holds the clear state. At this time, the signal e is
When the selector f is Low, the input A is selected and the signal g is Low.

As a result, selector b selects signal a and outputs it as signal i. Here, when the clock is at the signal h, as shown in Figure 2, print data n ₁ read from the memory passes through the selector b, is conveyed to the TPH.

At the rising edge of signal h, flip-flop d is inverted and signal g goes high.

Therefore, the original memory data n ₂ at the next clock was supposed to be transferred to the TPH is, since is selected the input data B by the selector b, the output data i to the TPH becomes GND. (Here, GND means blank data of TPH.) In addition, the flip-flop d is inverted again by the clock,
The signal g becomes low again.

As described above, when the sub-scan is an odd line, only the odd dots in the main scanning direction are valid as print data.
Similarly, when the sub-scanning direction is an even line, the selector f
Is selected, the initial value of the signal g starts at High, and only the even-numbered dots in the main scanning direction are valid as print data.

When performing line drawing printing, the control means (not shown), when recognizing the line drawing printing, sets the signal c to Low and sets the flip-flop d.
Is kept in the clear state. Further, the control means changes the signal e to Lo
Since it is held at w, the output signal g of the selector f always indicates Low. Therefore, the selector b always selects the signal a and outputs it as the signal i. That is, all print data is valid.

[Effect of the invention]

The present invention can be used inexpensively and effectively by switching the operation mode between the line drawing and the face drawing, and it is possible to obtain a good quality face drawing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a timing chart in FIG. 1 when the sub-scanning direction is an odd number, and FIG. 3 (A) is an explanatory view showing an example of a conventional print dot. ,
FIG. 3B is an algorithm diagram in a conventional example. b: selector d: flip-flop f: selector

Claims (1)

(57) [Scope of request for utility model registration] At least a memory for storing image data input from the outside, a print correction means for controlling print data read from the memory, and a drive based on output data of the print correction means A print head, wherein the print correction unit is configured to perform printing of a face image, and when the print data is print data of an odd-numbered line in the sub-scanning direction of printing, the print correction unit is configured to print one line. The print data of one of the odd-numbered and even-numbered dots of the print data is validated, and the print data of the other dot is replaced with non-printed data and output. In the case of the print data of the first line, the print data of the other odd-numbered or even-numbered dot of the print data of one line is regarded as valid. The thermal transfer type multi-color printing, wherein the print data of one dot is replaced with non-printing data and output, and when printing a line drawing, all the print data read from the memory are output as valid. Printing device.