JPS6078773A - Printing apparatus - Google Patents

Abstract

PURPOSE:To perform high speed printing for imparting high image quality with high reliability by using a highly economical ink film, by simple constitution wherein the current supply heat generation of a resistance layer is controlled by simultaneously opening and closing high and low potential switches alternately connected to a large number of recording needles of a recording head. CONSTITUTION:A large number of recording needles L1, H1, L2, H2... are mounted to the plate shaped electrode substrate of a recording head and low and high potential switches 51, 50 are alternately connected to said needles. These needles L1, H1... are uniformly and well contacted with the resistance layer of an ink film and the supply of a current to the resistance layer and a current supply time are controlled by the simultaneous opening and closing of the switches 50, 51 while the area of molten ink based on resistance heat generation is changed and multi-value recording is simultaneously performed by a large number of the needles 21. By this method, high speed printing imparting high image quality can be performed with high reliability by using a highly economical ink film through simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device capable of gradation printing.
The present invention relates to a printing device capable of expressing gradations using a total heat generation type thermal transfer film. More specifically, the present invention relates to a printing device that outputs printed matter such as a color photograph.

The main purpose of the present invention is to produce color television images, and furthermore, it is possible to develop a printing device that does not use expensive silver halide film and has high speed, high image quality, and high reliability at a low cost. 1
It's about doing.

Further, the present invention is not limited to the above-mentioned printing, but also relates to a printing device that outputs color printed matter, such as a printing device for a color copying machine, a hard copy device for a color graphic processing device, and the like.

In the current era of 'li7 information,' color display devices, which are output devices, are becoming more and more popular. In response to this, several attempts have been made to color printing apparatuses. Examples include an inkjet recording method, a thermal transfer recording method, and a wire dot recording method. Although these methods have some drawbacks, they can be used in several colors (7 to 7 colors).
It can be used as a color printing device (approximately 16 colors) and is in practical use. However, copying a color television screen using these printing devices requires additional effort.
It is difficult to achieve high speed, high image quality, high reliability, and low cost, which are the objectives of the present invention, with the above method. The reason for this will be briefly explained. All of the above methods are binary recording methods (in some cases, 3 or 4 values are possible); in other words, they are binary recording methods that either print one dot or not. In order to express halftones, it is necessary to use signal processing such as the matrix plane gradation method or the dither method, in which several dots are used as one unit. Using these methods significantly increases the cost and also results in slower printing speeds and lower image quality. Such a problem is caused by second-place recording, and the only solution seems to be to use a multilevel recording method.

Currently, there is an electrically conductive thermal transfer recording method as a method that allows multilevel recording and color printing. This method will be explained using FIGS. 1 and 2.

FIG. 1 shows several examples of structures of ink films for electrically conductive thermal transfer recording. 1 is the melting ink layer, which is a layer in which pigment or pigment and dye are dispersed in wax;
It has the property of being mild at temperatures around ℃. 2 is made of resin film or capacitor paper using PET etc. (a)
This layer becomes the support layer for this film. Reference numeral 5 denotes a layer in which fine carbon powder is dispersed in one finger, and is electrically conductive (hereinafter, 6 is referred to as a resistance layer). 4 is a conductive layer like 6, but in the case of (b) and (e), this layer becomes the film support layer. 5 is a color prevention layer, which is made of heat-resistant SI
It is I + ¥ layer. An electric current is passed through the resistance layer of these films, and the rainbow ink layer is melted and dissolved by the Joule heat generated, and the ink layer is transferred to the paper to be transferred, thereby performing printing.

Although each film structure in FIG. 1 has its own characteristics, they will not be mentioned in this specification.

Figure 2 shows the principle of multilevel recording. (a) shows a cross section. FIG. 2(a) shows an example of the ink film 19 having the structure shown in FIG. 1(a).

10 is a transfer paper. Using the recording needle 6 and the common electrode 7,
Wire the power supply 8 and switch 9 and close the switch 9.
A current 11 flows through the resistive layer 3. (b) is a diagram showing (a) from above. The distribution of current 11 is shown. Since Joule heat is proportional to the square of the current density, the temperature distribution is as shown in (,). 12.1 depending on how long switch 9 is closed! A difference in temperature distribution occurs as shown in l. There are 12 examples where the closed time is short and the amount of heat generated is small.
It is. Tm14 is the melting temperature of the ink, and in a temperature range higher than Tm, the ink melts and is transferred to the transfer paper 10. Corresponding to the temperature distribution of 12.13, the area of the transferred ink changes as shown in 15.16. Multi-level recording becomes possible by changing the time during which the current flows in this manner.

The next important thing is high-speed recording. To do this, it is essential to be able to record simultaneously with a large number of needles.

FIG. 3 shows an example in which a plurality of recording needles are used.

19 is an ink film, and 7 and 6 are a common electrode and a recording needle as in @2 (b). A simplified equivalent circuit of FIG. 3 is shown in FIG. 7 and 6 correspond to a common electrical connection and a recording needle, respectively. Each recording needle is connected to a power source 8 through a switch 9. 17, rl is the equivalent resistance between the recording needle and the common electrode, and r is the equivalent resistance between adjacent recording needles.

As is clear from Fig. 4, except for the case of r I(r It is impossible to fully control the current of the recording stylus only by opening and closing.Furthermore, even if r 1 << r 2 is realized, the common electrode and multiple recording stylus can be uniformly controlled as shown in Figure 3. It is very difficult to make electrical contact with the resistive layer.

To summarize the problems here, when putting into practical use a recording system using a large number of recording needles using the ink film with the above-mentioned resistive layer, the most important problem that must be solved is the first. Firstly, electrical contact can be made more uniformly without mistakes, and secondly, recording can be performed simultaneously with a plurality of recording needles. The present invention solves the above problems and achieves even higher reliability and lower cost.

The present invention will be described below.

FIG. 5 shows a recording head 22 used in the present invention. The material of the electrode substrate 20 is preferably ceramic from the viewpoint of reliability such as heat resistance and i=I durability, but inexpensive materials such as glass epoxy can also be used depending on the purpose. 21 has a recording needle and has multiple needles. The number of recording needles varies depending on the signal to be recorded, but approximately 500 needles are required for recording television screens.

FIG. 6 shows the recording head 22 and ink film 1 of the present invention.
9 contact methods were shown. The main roller 50 is made of an elastic material such as rubber, and the transfer paper 10 is wound around the main roller 50 and fixed with a fixing jig 32. The ink film 22 is stored in a roll 53 and is wound up into a roll 34 along the direction of the arrow. 35 and 36 are ink film transport rollers. The end portion 23 of the recording head 22 is pressed against the main roller by a spring 37 with a skin 38.

By pressing the recording head having the structure shown in FIG. 5 against the ink film in the manner shown in FIG. 6, the recording needle and the resistive layer are brought into complete electrical contact. From Figures 5 and 6・
As is clear, the only recording electrode is the recording needle, and for this reason, the recording needle is Fl! It became possible to touch the resistive layer in an imaginative way.

Next, a method for recording and a method for performing gradation recording using a recording head having such ideal contact properties will be described.

FIG. 7(a) shows how to flow current. 40° 41 is a portion where the recording needle is in contact with the resistance layer, and 42 is a current.

The voltages are applied such that 40 is negative and 41 is positive. As in FIG. 2, by changing the energization time, the temperature distribution changes as shown in 43.44. 4
3 is a case where the energization time is short, and 44 is a case where the energization time is long. As a result, it is possible to add area gradation to each ink transferred as shown in 45.46. FIG. 7 shows a method for recording between all the matching side mold electrodes. For the power supply 8, use the positive side switch 50 and the negative side switch 51 alternately as shown in the figure, and
It is connected to the needle electrodes Hm and L1 to Lm. The number of needle electrodes is 2m (mij: positive integer), and the number of recording pixels is 2.
It becomes m-1. Then, connect the negative side switch (low potential switch) to the tL switch, the positive side switch (high potential switch) to the ■ switch, the needle electrode connected to the negative side to the L electrode, and the positive side? It is called the H electrode. Focusing on Hl, by not flowing one current between Hl and Ll, I
A pixel is formed between ll and Ll, and a pixel is formed therebetween by Hl and L2. In this way, all Lw
A pixel can be formed between the pole and the H electrode.

FIG. 9 shows an equivalent circuit when focusing on the k-th L electrode. A resistor 52 is interposed between all the H electrodes and the Lk electrode, and the way the current flows changes depending on how the H switch is turned on. This is similar to the conventional example shown in FIG. 4 and cannot be used. A method for solving this problem is the most important part of the driving method according to the present invention. The basic outline of this method is shown in Figure 9. (,) shows how current flows in the resistance layer, and '('b) is its equivalent circuit.

The potential of the H electrode 41 and the L electrode 4o u,b (b) is determined by the open/closed state of the switch as shown in the figure. The switch is 6"open" is 57.1"closed" is 58. In such an open/closed state, currents flow like 54 and 55.

At this time, currents such as 56 and 57 cannot exist in principle. Therefore, the equivalent resistance of this circuit is only 56 shown in figure (b) and &, ? , the current that flows is always determined only by the resistance between the matching electrodes. (b)
The equivalent circuit of 54 and 55 is established only when the directions (arrows) of the currents are opposite.
), the H switch and L switch must be closed for the same amount of time. For example, when the k@th H switch and L switch are closed, k+1
When the H-th switch is closed and the (k+2)-th L switch is open, a current of 57 is generated, which does not hold true. The tabs are not single-ended switches 60 and 61 in Figure 11(a), but double-sided switches 62, and the adjacent H and L switches as shown in Figure 11(b). Must open and close with the same signal. Figure 11(b)
So, 65 is Ll and Hl, 64 is Hl and N2.65
are the open/close signals for N2 and N2 switches. 65,6
4.65, the closed signal sections must be different from each other. 9th
When the recording method shown in the figure is used, one-sixth of all the pixels in one column can be formed at the same time. On the other hand, to form one row of pixels,
It is necessary to record six times at different times. FIG. 12 shows this. <-'), (b) and (C)
By opening and closing each switch 't-, one row of all pixels can be formed. A current 70 flows in the equivalent resistance 53 between adjacent electrodes as shown by the arrow.

As described above, the present invention uses a recording head with ideal contact properties to realize high-speed recording that can form a plurality of pixels simultaneously.

Examples will be described below.

<Example> The recording head shown in FIG. 13 was used. This shows the tip of the recording head. Ni-C on ceramic substrate 101
r102 and C! u103 is deposited, the entire electrode is formed by photoetching, and N1-W- is selectively deposited on this electrode.
P electroless plating was applied. As shown in Fig. 14, the number of recording needles is 318 each for the L electrode and the H electrode (the 14th
In the arrangement shown in the figure, L1 to L318. There are 636 needle electrodes on the H1 to I (51B) sides, and the number of pixels formed by these needle electrodes is 665. (P1 to P665 in FIG. 14). The pitch (P) 105 of the needle electrodes is 200μ. Using this recording head, as shown in No. 64, a conveyance line for transfer paper and ink film was constructed. The ink film is wound into two rolls, and as shown in FIG. 15, there is a part where there is no ink. 111 is yellow, 112 is magenta,
113 is cyan. 110 is a resistance layer.

FIG. 16 shows a block diagram of signals of the present printing apparatus. 1
20 is a video signal. It is a 121-digit accompaniment processing one-color separation circuit, and is displayed on 122 CRTs. 123 is RG
, B signals, and 125 is a circuit for inverse gamma correction and correcting the difference in color difference between the CRT and the main printing device. 124 is a pressure adjustment signal, which can be input to 121 and monitored on the CRT. A circuit 125 is a circuit that corrects printing so that the color tone displayed on the CRT is printed.The correction signal 155 is converted into 6-pit data by an analog-to-digital converter 126, and temporarily stored in a line memory 128.-
636 points are sampled from the scanning line. A shift register -129iC signal is sent from the line memory 128 in response to a signal from the printing order selection signal generation circuit 136. The shift register 129 is a 6-bit parallel 2
It has 12 stages. 212 rows means - 655 pixels in a line
It is the value of 1 of 3 of +1. The signal is sent from the line memory to the shift register in three parts. The signal sent to the shift register is once stored in a latch 130, and is converted into a pulse width at 131 according to this data. This signal is sent to each needle electrode 1 by a selector 132.
The signal is converted into a signal for opening and closing the switch 133 connected to the switch 34. The selector 132 selects the data (
] (converted into a pulse width) to each switch 136. Details of the selector and switch are shown in Figure 17.

Data converted to pulse width is input to 140 . Data is distributed to each switch 146 and 147 according to the recording order selection signal 141 (E101 to 5c2). 142 and 143 are non-inverting type and inverting type transistors with five-state output. 145 is a current limiting resistor, and 146 is a PNP
It is a type transistor and becomes an H switch. 147 is NP
It is an N type transistor and becomes an L switch. 14B(R
1-R6) is the equivalent resistance of the resistance layer of the ink film.

A basic logic diagram of this circuit is shown in FIG. 18 and Table 1. Table 1
0'' and '1'' in this figure are logically L level and H level, respectively. "Hz" is a high impedance state.

Table 1 Table 2 As is clear from Table 1, the output B1 (1
49) and the output B 2 (150) of the H switch are turned ON when D and C are 1'', and lightning and current flow from B2 to B1.

Table 2 shows the signals from 801 to SC4 in the 17th session. t
l, t2. The signal is divided into six times at t3 and distributed to each switch. At the timing tl, current flows through the equivalent resistances R1 and R4 of the ink film, as shown in FIG. 17. The signals in Table 2 are tl, t2 . At the timing of t3, respectively t+,, g 12 u (a)
A current flows as shown in + (b) s (c), and all pixels on the - line can be formed.

Gradation recording is performed by controlling the time of the current flowing according to the data input to 140 (pulse width of number a).The selector 132 and switch 136 in FIG. R1 of the first block corresponds to pixel P1 in FIG. 14, and R5 of the 106th block corresponds to 'P635.

The recording head, ink film transport system and signal processing,
A television screen was printed using the drive circuit. The equivalent resistance value of the resistance layer of the ink film is 4Ω. The voltage of the power supply 8 was 20v1 to form pixels in the column in arm seconds, the pulse width was 2.7mseconds, (2.7mseconds x a3mseconds out of 3 times),
480 rows of the entire screen were printed in 4 seconds in each of the three colors yellow, magenta, and cyan. The quality of the printed image was almost the same as that of a CRT screen. The size is 96X127. The recording energy is the maximum pixel (dot size of approximately 0.2 x 0.2 ann for a 2.7 msec pulse)
At that time, it was 0.5 mJ. When printing the entire screen at maximum density, a current of about 1A always flows, and the total power of WF recording is about 2
It was 0W. This energy is one-fifth to one-seventh of the thermal transfer method using a normal thermal head.

As in the above embodiments, the present invention makes it possible to copy a color CRT screen, and in addition to being capable of high-speed recording,
A simple recording head structure, gradation recording using a pair of L electrodes and I (poles), and low stylus energy that reduces the burden on the power supply and drive circuits, making it possible to create a color image printing device at an extremely low cost. It is something to do.

[Brief explanation of drawings]

FIGS. 1(a) to 1(C) are cross-sectional views of the ink film used in the present invention. FIGS. 2(a) to 2(d) are diagrams showing a method of performing all area gradation recording using an ink film and a conventional recording head. 3 and 4 are diagrams showing a conventional recording method and its equivalent circuit. FIGS. 5(a) to 5(C) are diagrams showing the tip portion of the recording head used in the present invention. FIG. 6 is a diagram showing the configuration of a conveyance system for the ink film and transfer paper used in the present invention. FIGS. 7A to 7C are diagrams showing a method of performing area gradation recording using the recording head of the present invention. FIG. 8 is a diagram showing the basic switch connections to each recording needle of the present invention. FIG. 9 is a diagram showing an equivalent resistance circuit between each recording stylus and adding several circuits. FIGS. 11(a) and 11(b) are diagrams showing a method for controlling opening and closing of a switch. FIGS. 12(a) to 12(c) are diagrams showing the basic opening/closing order of the switches of the present invention. FIGS. 13 and 14 are diagrams showing the recording head of the present invention. FIG. 15 is a diagram showing the ink film used in the present invention. FIG. 16 is a block diagram of the circuit of the present invention. 17 and 18 are diagrams of selector and switch circuits of the present invention. 3.4, 110... Resistance layer 1.111, 112, 113... Melting ink layer 10... Transfer paper 19... Ink film 22... ... Recording head 21 ... Recording needle 20.101 ... Electrode substrate 50 ... H switch 51 ... L switch and above Applicant Akira Co., Ltd.゛J Hoseikosha Agent Patent Attorney Tsutomu Mogami (Hisashi) (b) 1st ζC Figure 2, 1; 3 Figure 4 Zheng Figure 5 Figure -26! ;7 Fig. 107 (b) (shi) Fig. 11 Fig. 12 Fig. 16 +1) ( Fig. 14

Claims (3)

[Claims] (1) Using an ink film that has a resistance layer and a melting ink layer, the melting ink layer is melted by Joule heat generated by passing a current through the resistance layer, and is transferred to transfer paper to obtain a record,
The recording head is composed of a plate-shaped electrocup substrate and a plurality of recording needles, the recording needles are provided on one surface of the electrode substrate, and an L switch that opens and closes a low potential and an H switch that opens and closes a high potential. A printing device characterized in that it has recording heads alternately connected to the recording needles. (2) The printing apparatus according to claim 1, wherein the resistor layer is energized to generate heat by simultaneously closing the L switch and the H switch that are adjacent to each other. (3) The printing apparatus according to claim 2, wherein the melting area of the melting ink layer is changed by changing the time during which the current is applied.