JPS59171662A - Printing apparatus - Google Patents

Abstract

PURPOSE:To provide a low cost, high speed, high quality and low power full color printing apparatus, provided with a revolving apparatus operated following a synchronous signal when receives the signal from a generation apparatus for issueing an output signal in synchronous relation to the moving speed of recording paper. CONSTITUTION:A current supplied heat generating sheet 1 is brought to a roll form and heat meltable ink layers are applied thereto at every one page portion in the order of a yellow 95, a magneta 96, a cyan 97 and a black 98. After recording paper 8 is wound around a roll 80 to be fixed thereto, the position signal from a rotary encoder 91 is sent to a control part 90 from which in turn fed back to the roll 80 to rotate the same at a constant speed and transmitted to rollers 82, 83 and a recording head driving circuit 84 to perform positional alignment. The signal generated from the drive circuit (a recording paper speed synchronous signal generating apparatus) 84 is subjected to frequency dividing to generate pulses equal to the numbers of resolving powers of recording dots or 1/integer thereof while these pulses are used as the synchronous signals of the recording dots.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to a printing device, and more specifically, blood flow is caused to flow through a conductive sheet, and heat generated by Joule heat is generated. 7 fever#
;Relates to so-called energized heat-generating transfer in which a print is obtained by melting fusible ink and transferring it to transfer paper.

5. The solid ink is melted by the heat generated by electricity and transferred to the recording paper.
Various methods of copying on paper have been tried.

The basic concept is shown in Figure 1. The energizing 1 heat generating sheet 1 is
Current-carrying layer 2. Support layer 3. It consists of a heat-melting ink layer 4, and the support layer 3 may also serve as a current-carrying layer. The recording principle is as follows. When a voltage according to a recording pattern is applied to the recording electrode 5 by the signal voltage generator 7, a current flows to the return electrode 6 via the current-carrying layer 2. At this time, if the return electrode is made sufficiently larger than the contact area between the recording electrode 5 and the energized figure 2, Joule heat due to the energization will mostly be generated directly below the recording electrode 5. The generated Joule heat passes through the support 3 by thermal conduction and melts the heat-melting ink 4, and the melted portion of the ink is transferred onto the recording paper 8 and printed.

As described above, recording by energized heat transfer can be performed on plain paper. ■No noise. ■Can record gradations. ■Can record in color. It has the merits of Gin. However, despite having the above-mentioned advantages, the prospects for commercialization are extremely low compared to other printing methods, such as inkjet methods and thermal transfer methods using thermal heads. The following reason is due to rc.

The conventionally proposed electrical heating transfer method basically prints serially with a single recording electrode as shown in Figure 1, but in some cases it has multiple recording electrodes and one return electrode. , which is to drive multiple recording electrodes in a time-division manner.

The former has an extremely slow recording speed, and the latter requires as many fiber bars for driving the recording electrodes as there are recording poles, making it very expensive and requiring a high time-sharing duty. The drawback is that the input power for one stroke is high. For this reason, the development of electrical heating systems has been hindered, although they have various advantages.

In addition, mechanically, due to the relative misalignment between the signal speed of the recording electrode and the recording paper, the print quality transferred onto the recording paper may be uneven, and due to graphics, solid color, etc., color unevenness, The current situation is that streak-like voids occur and printed matter of surface quality is not provided. In addition, in a rotating device that supports and rotates the recording paper and has a fixed load on the recording electrode and the return electrode, voids are also generated due to poor contact between the recording electrode and the current-carrying layer. If the contact pressure is increased, various problems will occur, such as twisting of the paper, expansion of pits, and measures to deal with the load on the rotating device. On the other hand, if the current flowing through the recording electrode is increased, problems such as dealing with high voltage, dealing with heat, and increasing the power arise, resulting in an increase in cost.

The present invention has been made to eliminate the above-mentioned drawbacks, and its purpose is to provide a low-cost, high-speed, high-quality, low-power full-color printer, which will be explained in detail below with reference to the drawings.

The gist of the present invention is to use an energized heating recording head that selects a plurality of recording electrodes at the same time and performs time-division driving, and to synchronize the signal speed of the recording electrodes and the recording paper feeding speed, and to ensure proper alignment between the recording electrodes and the energized layer. The purpose is to achieve the above objective by realizing a rotation device by compression.

FIG. 2 shows a diagram of the principle of time-division driving of the recording head according to the present invention. Recording is performed between a plurality of pairs of return electrodes 101 to 104 that are arranged opposite each other as shown in the bar shape.
j Camellias 201 to 206 are arranged. Hereinafter, this pair of opposing return path electrodes will be treated as one.

Figure 3 shows the equipotential surface when different potentials are applied to the now adjacent return path 1' poles. Figure 3 shows that an energizing heating sheet having a 21! electrical layer is brought into contact with the recording head. This is the equipotential surface at the conductive J- when the potentials E(υ) and O(υ) are applied to the return path rgi and the poles 101 and 1.02, respectively.As shown in the figure, at this time, the return path'-pole 1020 divided area 1
Since there is almost no electric field entering 1, for example, if the recording chambers M 13 and 14 are simultaneously KOed (at a potential of υ1),
In the recording electrode 13, a current flows from the return electrode 101, and printing is performed according to the principle of energization and heat generation recording described above, but since the vicinity of the recording electrode 14 is at the same potential, no current flows, and therefore no printing is performed. . As described above, selective printing was achieved by arranging the return electrode and selecting the potentials of the return electrode and the recording electrode.

FIG. 2 1b) shows the driving principle according to the invention. The selection signal electrodes S, 301, 52302, 53303 are connected to recording electrodes 201-206 via backflow prevention diodes 501-506, respectively. For example, select the selection signal electrode 8, 301 (for example, O(υ)), 52302
．． 53303 is unselected (floating) icL, the return electrodes 101 and 103 are set vertically, 01υ) or E1
Apply υ1 at the same time. Regardless of the combination of applied potentials, as described above, the electric field tends to wrap around between the pair of opposing return electrodes, so the recording electrodes 201,
202 can be printed independently. Recording electrode 20 with one-way valve selection
3, 204, 205, 206 are return electrodes 101 and 103
A closed loop is formed between the two, but since the current is blocked by the backflow prevention diodes 503, 504, 505, and 506, no printing is performed. Next, when the selection signal electrode 302. or 303 is selected, the recording electrode 203.204 or 205.207 becomes
2 and 103, and 104 and 105, it is affected by the matching return electrode. Therefore, to avoid this, adjacent return electrodes are driven as a pair. For example, when selecting the selection signal electrode 302, the set of return electrodes 101 and 102, the silk of 103 and 104, and the selection signal electrode 303
When this is selected, all the recording electrodes can be driven by driving the set of return path electrodes 102 and 103 and the set of 104 and 105, respectively.

In order to drive two adjacent return electrode sets in the first half and second half by changing the combination so as to print one line as described above, 1. The following irregular time division method is used.

In other words, the number of selection signal electrodes is M, and the number of return electrodes is (2N+1
), then M+(2N+1) drive circuits are required
N recording electrodes can be driven, in which case 1
During one selection period, N recording electrodes perform one recording at the same time, and the duty becomes 1/'M. This'11. C. Compared to conventional multi-heads, assuming the same speed, the selection time is N times longer, so the power can be reduced to a large IM, and the number of drive circuits is also significantly reduced, which improves image quality. It is possible to reduce costs over time.

By the way, the electrode shape and driving principle described above are similar to those of a static printer with a multi-stylus, but in the energized heat-generating transfer method, time-division driving is not possible with the conventional driving method of a multi-stylus electrostatic printer. What is achieved for the first time by the drive method according to the invention is shown below.

In contrast to the electrode configuration shown in Figure 4, in conventional multi-stylus electrostatic printers, C
A selection signal is applied to 1101 to C6105, and the recording electrode side is divided into A group and 8 groups 21, and each of them is driven alternately and simultaneously. In the energization heat transfer method, when such driving is performed, the potential distribution in the energization layer becomes as shown in FIG. 5. In FIG. 5, the opposing return electrodes 101 are selected, for example, as E(υ), and the adjacent recording electrodes 207, 208, and 209 are selected as ○.
(vl shows the potential distribution in the current-carrying layer when the others are floating. Between each recording electrode set to 0 [τ),
Since there is no potential gradient, the recording electrode is placed independently at O(υIKl,
The current density decreased compared to when the recording electrode 20 in the middle
Most of the current flows through 8 and there is a force. As a result, uneven printing and missing printing occur.

In the driving method according to the present invention, 301 to 31 on the recording electrode side
8 and simultaneously apply signal voltages according to the data to the return electrodes 101 to 105. Therefore, only one recording electrode is always selected for one set of return electrodes, so the above recording is possible. No electric field leakage occurs between electrodes. As described above, although the present invention looks similar to a multi-stylus electrostatic printer, it is a novel printer based on a completely different driving principle.

Next, gradation recording according to the present invention will be described. Recording electrode 201 and return electrode 1 when the recording head according to the present invention is brought into contact with a heat-generating sort having a current-carrying layer and an ink layer and is energized.
Figure 6 Cα)K schematically shows the potential distribution of the current-carrying layer according to 01.
Indicated. There is a very steep potential gradient near the recording electrode. Therefore, the heat distribution of the heat generating sheet due to the heat generated by energization is 1b
As shown in 1, it becomes a mountain shape with a peak in the center. The dotted line indicates the case where the input energy is larger than the solid line. In the figure, the vertical axis is the temperature, and the horizontal axis is the position corresponding to the figure (α).

If T8 is the melting point of the thermofusible ink, the area of the heat distribution cut by T8 changes depending on the input energy. In other words, area modulation is applied to the printed dots depending on the applied energy. Figure 7 shows the relationship between printing energy and optical density. Since modulation is applied to one dot, there is no need to construct a matrix, which is very advantageous in terms of cost and speed. In terms of color printing, full-color printing has become possible by selecting thermofusible inks of yellow-magenta, -cyan, and, if necessary, black.

Examples are shown below.

Example 1 FIG. 8 shows an example according to the present invention. Figure (A1=
4.4ms g Zz= 0.6rug, A3=
IIIJ recording electrode pitch P2=200 μm. Figure (b) shows a conceptual diagram of the driving method. The division is M=50.
N=1 (l, 50 selection signal electrodes S1301~Ss
6350 and 2N+1=21 return electrodes lO1~121
Accordingly, NXM=500 recording electrodes are driven. The recording electrode starts from the center of the return path type @11.01, 121
Hl tyn at a density of 5 dots/MJl to the center of
It is arranged in width. Therefore, as described above, when selecting the selection signal electrodes 301 to 325, the return electrode is
and 102, 103 and 104. . ,, the threads 119 and 120 are combined and driven together, and the selection signal electrode 32
When selecting 6 to 350, return electrodes 102 and 103
．． 104 and 105°. . It is driven by a combination of 120 and 121. By performing such driving, it was possible to perform normal printing even on the recording rod placed between adjacent return electrodes.

FIG. 9 shows a timing chart of drive waveforms.

Selection signals 401 to 450 are selected from selection signal electrodes 301 to 350.
As shown in the figure, the localization is ○rυl at the H level and floating at the L level. At the timing of the signal 30, for example, when it is at H level, the return electrodes 101 and 102 are
3 and 104. ,. . 119 and 120, 102 and 103 at L level, 104 and 105,... 120 and 12
With a combination of 1, a signal corresponding to the write data is applied.

In this embodiment, 16 gray levels were achieved by pulse width modulating the voltage applied to the return electrodes 101 to 121 in 16 steps.

FIG. 1O shows an example of a drive circuit. Control section 4]
LS signal 31 indicating the beginning of one line from to the image signal generating unit 40
and sends the request clock 32 (500 Pu1s).

The 4-pit pixel data synchronized with the sent request clock 32 is a ROM for image processing such as gamma correction.
When the address of the table 42 is input, an image processing table corresponding to each color or output content is selected using a multi-bit signal 51, and is transferred to the shift register 44 as 8-bit pixel data 52. The shift register 44 is 8 bits parallel and has 10 stages. After the transfer is completed by the transfer clock 33, the preset counter 45 is set by the signal 34. The preset counter 45 receives an 8-bit input and counts by the clock 53 to create a pulse width according to the input data. A flip-flop 46 is hit with the set signal 35 and the carry obtained from the preset counter to generate a pulse according to the data. Pulse width modulation is performed as described above, so although there are 16 gradations, there are 256
You can select the gradation in gradation steps.

The obtained modulated pulse is sent to the distribution unit 47 to select two spaced combinations of the return electrodes 101 to 121 using the signal 30, and the drive unit 48 converts it into a driving voltage and outputs it to 21 return voltages 101 to 121. be done.

- Force selection signals 401 to 450 are obtained by a 50-stage shift register 49 using a clock 58 and a timing signal 59r, and are outputted from a high withstand voltage fiber 60 of the oven drain to selection signal electrodes 301 to 350.

FIG. 11 shows a conceptual diagram of a full-color printer according to the present invention. A recording paper 80 wound around a roller 80 and an energized heat generating sheet 1 supplied from a sheet supply section 82 via a feed roller 85 are overlapped on the roller 80 and recorded by a recording head 81. The head is pressed against the roller 80 by a presser spring 88 to maintain an appropriate pressing pressure and to maintain uniform contact between the recording head 8 and the normal heat generating sheet 1 and the recording paper.

The energizing heating sheet 1 is in the form of a roll, and as shown in FIG. 12, the heat-melting ink layer is yellow 95I magenta 96. Cyan 97. Plaques 98 are applied one page at a time. Therefore, four figures of writing are performed to obtain one full-color record. Therefore, highly accurate positioning is required when overlapping colors. In the present invention, the recording paper 8 is wound around a roll 80 and fixed, and the absolute position is determined by a rotary encoder 91.

The position signal from the rotary encoder 91 is sent to the control unit 91-\, and is sent to the constant speed rotating roll 80.
82. Sheet feeding slope for feedback and positioning. A signal is sent to the sheet winding roller 83, the recording head, and the drive circuit 84.

As a result of various experiments conducted in accordance with the present invention, it was found that an elastic body best matched the flatness of the roller 80, the recording head 81, and the close contact of the recording paper 8. Among them, it has been found that a roller with no rubber roller shown is more suitable because of its uniformity of pressure.

The hardness of the rubber roller is an important parameter as it is related to the diameter of the rubber roller, and HC45 to 55 is appropriate. Also, the roller diameter due to the contact property is φ (a) ~ φ80 'tu
g is a good condition, and the pressing pressure is 1.5~2°5TI.
y/(7)2 is an important condition for achieving high quality. Next, a rotary encoder is used because it is necessary to electrically align the recording paper 8 and the recording electrodes 201 to 250, but the signal generated from the drive circuit 84 (recording paper speed synchronization signal generator) is used for highly accurate positioning. The number must be equal to the resolution of the recording dat in the recording paper feeding direction from the top of the alignment, or the synchronization signal of the recording dat must be multiplied by an integer and the pulse frequency divided by an integer. used as

Although the present invention has been described in detail above, the present invention can also be applied to a full-color printer using a plurality of recording heads.

Now, the effect of the present invention is that the rotation device receives a recording speed synchronization signal that outputs an output signal in synchronization with the moving speed of the recording paper, and a signal from the recording paper speed synchronization signal generator, and operates in accordance with the synchronization signal. The details include the proper diameter, hardness, pressure, etc. of the rubber roller, and by emitting a generation pulse of an output signal equal to the resolution of the recorded data, it improves color matching defects caused by conventional alignment defects and eliminates voids. This has made it possible to create a high-resolution, high-speed, full-color printer that eliminates spots at a low price.

[Brief explanation of drawings]

Figure 1 shows the principle of the conventional energized heat transfer recording system. FIG. 2 (a+ 1bI I-i) shows a principle diagram of the recording head according to the present invention. FIG. 3 shows the potential distribution of the current-carrying layer by the return electrode. FIG. 4 shows the driving of the multi-stylus electrostatic printer. FIG. 5 is a diagram showing the electrode shape showing the NL principle. FIG. 5 is a diagram showing the potential distribution in the current-carrying layer when the driving method of the multi-stylus electrostatic printer is used. FIG. FIG. 7 is a diagram showing the potential distribution and temperature distribution of the current-carrying layer due to the head. FIG. 7 is a diagram showing the relationship between input energy and printing density in the present invention. FIG. 8 1 α) j7; + is 1 is a diagram showing an outline of a recording head according to an embodiment of the present invention. FIGS. 9 and 11 are diagrams showing various driving signals and driving circuits. FIG. 11 is a diagram showing a conceptual diagram of a printing apparatus according to the present invention. FIG. 12 is a diagram showing the energized heat generating sheet used in the present invention. Current-carrying heat-generating sheet-1 Current-carrying layer-2 Heat-melting ink-4 Recording paper-8 Return path electrodes-101 to 121 Recording electrodes-201 to 250 Selection signal 'r! Mi-301-350 Backflow prevention diode-501-350 ROM table-42 Recording roller 80 Recording head-81 Presser spring-8
8 Drive circuit 84 Sheet feed roller 82 Sheet winding roller 83 Position detector 91 Positioning controller 90 Applicant Suwa Seikosha Co., Ltd. Representative Patent Attorney Mogami Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (11) A printing device which obtains a record by melting ink by heat generated by energization and transferring it to recording paper, between a return electrode divided into a plurality of pairs and a return electrode. A printhead having a recording head having a plurality of recording electrodes arranged in a time-divisionally driven manner, a drive circuit, a recording roller, an energized heat-generating sheet having at least a conductive layer and a heat-melting ink layer, a sheet feeding roller, and a sheet winding roller. In the copying apparatus, a recording paper speed synchronization signal generator outputs an output signal in synchronization with the moving speed of the recording paper, and a circuit that receives a signal from the recording paper speed synchronization signal generator and operates in accordance with the synchronization signal. A printing device characterized by having a rotating device (21) A rubber roller is used for the rotating device, and the diameter of the rubber roller is set to φU] to φ80. The printing apparatus according to claim 1 and 2, characterized in that the number of output signals from the recording paper speed synchronization signal generator is equal to the resolution number of recording dat in the recording paper feeding direction. (4) A patent characterized in that the number of output signals from the recording paper speed synchronization signal generator t is equal to ] times the resolution of the recording dat in the recording paper feeding direction. The printing device according to Claims 1 and 2! JiIK. 151 The hardness of the rubber roller of the rotating device is HC45 to H.
The printing device ft according to claims 1 to 4, characterized in that the oil is C55. (6) Patent claims characterized in that the adhesion force between the recording electrode head and the energizing W is set in the range of 1.5 Kf/cm2 to 2°5 Kf/cm2. The printing device described.