JPS5853460A - Heat transfer printer - Google Patents

Abstract

PURPOSE:To enable to always perform printing in a high density and with high quality, by a method wherein the reflective density of a printing paper before printing and that of blank part of the paper immediately after printing are detected, and the heating power of a thermal head is controlled so that the difference between the densities detected becomes constant. CONSTITUTION:A detector 12 for the reflective density of the printing paper 3 before printing is provided at a former stage of the thermal head 2, while a detector 13 for the reflective density of the blank parts left between characters or symbols on the paper after printing is provided at a later stage of the head 2. Both detection signals are fed into a comparing circuit 15 through a memory circuit 14, and are compared to each other on the basis of a printing command 19, and when there is a difference between the signals, a command for correcting a voltage impressed on the head 2 is fed to correcting circuit 16. Accordingly, it is possible to always print in a high density and with high quality, in response to changes in the ambient temperature and the temperature of the thermal head.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer printing device that prints on paper using a thermofusible intercalant.

Recently, data Asahi's technology has been improved and expanded to %! In the field of 1'&, =MBI-YU has come to be used, and printing devices using various methods have been proposed for outputting I&O data.

Among them, printing devices that utilize thermal transfer methods are attracting attention as a simple, highly stable, and economical output device.

Fig. 1 explains the printing mechanism in such a printing device.
The nine heating resistors 4 provided in the thermal head 2 between the printing papers 3 and 0 are energized, and the ink? By heating from the side of f-no-10 pace 5, the heat-melting pie/melo coated on the side of p-pace 5 is melted, and the ink 1 contained in the binder is transferred onto printing paper 3 for printing. It is carried out.

Conventionally, thermal transfer printing devices use the heat generated by the thermal spatula V- as energy for printing, so the amount of heat generated by the head has a large effect on printing quality, and it also depends on the surrounding temperature, printing device, printing paper, etc. Alternatively, printing quality may be greatly affected by the temperature of the ink cleaner, etc. For example, when the ambient temperature is transmitted, the thermal energy for melting the ink is insufficient, and the ink completely peels off from the ink cleaner. Because the printed characters, symbols, etc., remain on the ink clean without being washed away, the printed characters, symbols, etc. become blurred. Excess ink near the heating resistor is also deposited on the printing paper.
The ink melted in the margins between characters that should not have been printed. This may cause stains.

828B At %O, which indicates this situation, ink is transferred to the margin part 8 between 30 characters on the print paper printed by the thermal head (i.e., a place that should not be printed), and the print quality is significantly degraded. It shows signs of deterioration. In order to avoid the above-mentioned drawbacks, in the past, -? - A method is adopted in which a voltage adjustment circuit is provided for adjusting the voltage applied to the mark r, and the operator adjusts the voltage applied to the p by increasing the voltage as necessary, thereby optimizing the printing density. h is *Environmental conditions, if the ambient temperature or paper temperature changes in 49, or if the thermal head is replaced, in i1, the applied voltage adjustment -9m-m should be adjusted to 1lIt/
There is a disadvantage in having to do so.

The present invention is proposed by Kadoro Kushijo K1m-)#&)
The objective is to provide a thermal transfer printing device that can provide high-resolution and high-quality printing.

Below, please refer to the attachments mw and t for a detailed explanation of the unexploded train.
do. - 1X'Ar11o*marty111o-*11s %
In eD, the digital transfer ink qeyx is on supply reel 1.
The supply reel 10 heats up and passes between the front side of the thermal spatula WZO and the printing paper 3 on the back plate 9. Therefore, in the front stage of the thermal spatula 1P2, there is an O-printed M paper 3k in front of the impression, and a detection device 13 for detecting the reflection density is installed.After the thermal head 2, RFC company printing 78j110 printing
The margin dedicated to the letters, III is 0 @ minute O reflection density I!
A detecting device 13 for detecting is arranged. Detection device 12. Is can move from the light emitting element and the light source to the thermal spatula P2 and %. t
- Back Luhetsu IF! A portion of the printing paper 30 on the movement path of the heating element (not shown in 011) is placed at a position where tW can be determined.
)%The latter stage detection device 13 is the first stage O detection device 120111
A detection device 13 is installed at a position where it is possible to adjust the same zero point as the fixed point. Thermal spatula P1! , a detection device 13 is provided. 14 is a storage circuit that stores the signal from the detection device 12; 1! ! is the detection device 13 and the storage device 1.
A comparison circuit compares the signals from 4, 1- is a comparison circuit Is
One of the correction circuits outputs a correction signal (according to a signal from the correction circuit 16), and one is a head drive circuit that provides an output to the enlarger 1118 according to the correction signal of the correction circuit 16 in response to the print command 1eK.

Next, the operation 1 effect in the above embodiment will be explained.

The storage circuit 14 receives and receives the signal of the reflection density of the printing paper 30 before printing from the detection device 12, and then sends it to the thermal head 2.
] Printing is performed, and the printed capital letters and margins between symbols are stored in memory until they reach the detection device 130 position and the detection device 13 detects the reflection density at that location.

Then, the signal of the reflection density of the blank area after printing is transferred from the detection device 13 to the comparison circuit 15, and at the same time, the storage circuit 1
4 selects the reflection density signal of the fixed point in the field whose reflection density was detected by the detection device 13 and transfers it to the comparison circuit 14. Knowing that the margin 0 portion has come to the position of the detection device 13, the transferred 92 O signals are compared to see if there is a difference. If there is a difference, Kfl is sent to the correction circuit 16 to correct the voltage applied to the thermal head 2. The part O reflection 11IIt of the margin after printing detected by the detection device 13 is the reflection 1 before printing.
If it is higher than 1JIE, this indicates that the ink has been transferred to a place on the printing paper 3 that should not be printed, and that the voltage applied to the thermal head 2 is too high.
P), the correction circuit 16 issues a correction command to lower the applied voltage.On the other hand, in the O case where the degree of reflection before and after printing is constant, ink is not transferred in the margin of the printing paper 30,
In this case, there is a possibility that the printed character or symbol O transfer density is insufficient.

In the latter case, the correction circuit 16 is connected to the thermal head 2.
A correction command is issued to 5 to increase the applied voltage.

-) The correction circuit 16 issues a correction command to lower the voltage applied to the thermal spatula Pg only when the value of the degree of reflection a after printing is higher than the value before printing, and raises it at other times.

As explained above, by giving control to the thermal head 2 so that the difference in reflection density becomes a problem, the ink O transfer on the ink cartridge #y is always at its peak state, that is, at high backlight and high It is carried out in a relaxed state. Since the print density O control is performed by comparing the print results in this way, it is possible to automatically correct changes in illumination conditions, such as changes in ambient temperature.

In the above embodiments, only the means for correcting the voltage applied to the thermal head in order to obtain high-quality printing has been described; -! Of course, it is also possible to control the amount of heat generated by the head O.

As explained above, according to the present invention, there is provided a detection device that detects the reflection density of the printing paper before printing and a detection device that detects the printing paper O reflection once from the extra thick part of the printed IlO character and the symbol jump. 1 Go for printing detected by the detection device
By adopting a configuration that controls the amount of heat generated by the thermal head so that the reflected density has a constant difference), high-density and high-quality printing is always possible in response to temperature changes such as ambient temperature and thermal head 011 heat. be able to.

[Brief explanation of the drawing]

No. 111 is a partially enlarged cutaway diagram illustrating the printing state of a general Nermal Transfer Ink Clean. No. xml is a diagram showing a printing state when the amount of heat generated by the printer head increases. FIG. 3 is a schematic diagram illustrating an embodiment of the present invention. With this ζ, 2-Nermal Hetsu IP, 12. 15- (reflection density) detection device. Patent applicant Canon Co., Ltd. Figure 1 Figure 2 Figure 3 Seal

Claims (2)

[Claims] (1) A detection device is installed in the front and rear stages of the thermal spatula 20, and the printing 11i before printing (using the armpit front and rear O detection device)
, o The reflection density is detected, and the latter detecting device detects the reflection density of the blank area of the printing paper after printing. A circular transfer printing device characterized in that the amount of heat generated by the thermal head R is controlled so as to coincide with each other. (2) If the O reflection density before printing detected by the front-stage detection device and the reflection density of the margin after printing detected by the rear-stage O detection device are equal, increase the heat generation amount of fw r. The server according to claim 1, further characterized in that: Transfer printing device.