JPS59171664A - Printing apparatus - Google Patents

Abstract

PURPOSE:To provide a low cost, high speed and high quality color printing apparatus, constituted of such a mechanism that a plurality of recording electrodes are simultaneously selected and time sharing driving is performed while areal modulation is applied by input energy. CONSTITUTION:An LS signal 31 showing the front of one line and a request clock 32 are sent to an image signal generating part 40 from a control part 41 and a pulse corresponding to data is formed through an image treating ROM table 42, a shift register 44, a preset counter 45 and a flip-flop 46. A modulation pulse is outputted to return electrodes 101-121 from a distribution part 47 through a drive part 48 while two adjacent combinations of the return electrodes 101-121 are selected by a timing signal. A selection signal is formed in a shift register 49 by a clock 58 and a timing signal 59 and outputted to selection signal electrodes 301-350 from a highly pressure resistant driver 60 of open drain.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, and more specifically, the present invention relates to a printing device, and more specifically, by passing an electric current through a conductive sheet, heat-melting ink is melted by the heat generated by the sheet, and the ink is transferred to a transfer set. The present invention relates to so-called energized heat-generating transfer to obtain a print.

Various attempts have already been made to melt solid ink using heat generated by electricity and transfer it to recording paper.The basic concept is shown in FIG. The energizing heat generating sheet 1 consists of an energizing layer 2, a support layer 3, and a heat-melting ink layer 4, and the supporting layer 6 may also serve as the energizing layer.

The recording principle is as follows. When a signal voltage generator 7 applies a voltage corresponding to a recording pattern to the zero recording electrode 5, 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 current-carrying layer 2, Joule heat due to energization is generated directly below the electrode 5. The generated Joule heat passes through the support filter by thermal conduction [7] and melts the heat-melting ink 4, and the melted portion 10 of the ink is transferred to the recording paper 8, thereby making a print.

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 advantages such as However, despite having the advantages mentioned above, the prospects for commercialization are extremely low compared to other printing methods such as inkjet methods and thermal transfer methods using thermal heads. This is due to the following reasons.

The electric heating transfer method that has been proposed in the past basically performs serial printing with a single recording electrode as shown in Figure 1, or has multiple recording electrodes and one return electrode. Either multiple recording electrodes were driven in a time-division manner.

The former has an extremely slow recording speed, and the latter requires as many drivers to drive the recording electrodes as there are recording electrodes, making it very expensive and requiring a high time-sharing duty, which requires the input of 1ilIlI element. The power increases,
There is a drawback.

Furthermore, in the structure of the recording head, uniformity of recording dots cannot be obtained due to variations in the dimensional positional accuracy of the electrodes and unevenness in the flatness of the contact surface with the current-carrying sheet. Currently, high-quality prints are not provided. In addition, heat accumulation and electric m due to accidents such as paper jamming etc.
It had the disadvantage of insufficient durability due to damage to the head surface caused by the 1 tfl discharge. For this reason, although it has various advantages, the development of the electric heating method has been hindered.The present invention eliminates these disadvantages, and its purpose is to provide a low-cost, high-speed, high-quality full-color printer. be.

The gist of the present invention is to simultaneously select a plurality of recording charges (11,
Moreover, it performs time-division driving, is inexpensive, has high precision, high density,
The object is to achieve the above object by realizing a highly durable electrically heated recording head.

FIG. 2 shows a diagram of the principle of time-division driving of the recording head according to the present invention. As for the electrode shape, as shown in (a), recording electrodes 201 to 206 are arranged between a plurality of pairs of return conductors AI+i l 01 to 104 that are arranged opposite to each other. Hereinafter, this pair of opposing forces will be treated as one electrode.

Figure 6 shows the equipotential surfaces when different ffi levels are applied to the electrodes that are in conflict with each other. FIG. 6 shows an electrically conductive heating sheet having a conductive layer brought into contact with the recording head.
These are the equipotential surfaces in the conductive turtle layer when potentials K (v) and 0 (V) are applied to 01 and 102, respectively.

As shown in the figure, at this time, there is almost no electric field entering the divided region 11 of the pole 102, so for example, if the recording electrodes 13 and 14 are set to a potential of 0 (■) at the same time, In the recording electrode 13, a current flows from the return electrode 101, and printing is performed according to the principle of energization heat transfer described in 7 above. Therefore, no printing is done. By arranging the return electrodes as shown below, selective printing could be achieved by selecting the potentials of the return electrodes and the recording electrodes.

FIG. 2(b) shows a driving principle according to the present invention. Selection signal 'fjl, pole 8, 301, S2502, S, 3
C13 indicates the backflow prevention diodes 501 to 5o6, respectively. It is connected to four city poles 20i to 206.

For example, select the selection signal electrode S, 501 (for example, 0 (V)
) L, S230'2, S, Ro03 not selected (70~
0(v) or E(v) is simultaneously applied to the return electrodes 101 and 106 independently.

Regardless of the combination of applied potentials, as described above, the electric field does not wrap around between the pair of opposing return electrodes, so the recording electrodes 201 and 202 can print independently.One-way feed selection Recording electrode 20!1, 204, 205,
206 create a closed loop between the return electrodes 101 and 103, respectively, but the backflow prevention diodes 503, 504.
Since the current is blocked by 505 and 506, no printing is done. Next, when the selection signal' electrode 302 or 06 is selected, the recording electrodes 203, 204 or 205, 207 are connected to the return electrode pair 101 and 102, respectively.
．． 103 and 104 or 102 and 103.104 and 10
5, it is affected by the adjacent return electrodes. Therefore, to avoid this, adjacent return electrodes are combined and driven. For example, when selecting the selection signal electrode 302, the set of return electrodes 101 and 102 and the set of return electrodes 103 and 1 are selected.
When the silk of 04 and the selection signal electrode 306 are selected (17), all the recording electrodes can be driven by driving the silk of path electrodes 102 and 103 and the silk of 104 and 105, respectively.In fact, all the recording electrodes can be driven. Divide one sub-scanning period 171 into the first half and the second half, for example, in the first half there are
2. 106 and 104 pairs, 102 and 103 in the second half.
The silks 104 and 105 are driven in pairs.

By the way, when different potentials are applied to the Hyl path electrode set, a current also flows between the return path electrodes. But - is the area of the return path electrode recorded? (J is sufficiently large compared to the poles, so the ta flow density is sufficiently small, so there is almost no problem.

As described above, when printing one line, the silks of two adjacent return path electrodes are driven in different combinations in the first half and the second half, resulting in the following irregular time division method. In other words, if the number of selection signal electrodes is M and the number of return electrodes is (2N+1), 111+(2N+1) drive circuits are required to perform M
N recording electrodes can be driven. At this time, 1
Writing is performed simultaneously using N recording electrodes during one selection period, and the duty is 1/M. Assuming the same speed compared to the conventional multi-node, the selection time is N times longer, so the power can be reduced to 1 (IM), and the number of drive circuits is also significantly reduced, so the image It is possible to reduce costs over time.

By the way, the electrode shape and driving principle described above are similar to those of an electrostatic printer with multiple styluses, but in the current heat transfer method, time-division driving is not possible with the drive method of conventional multi-stylus electrostatic printers, and this is not possible. 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 Fig. 4, in conventional multi-stylus electrostatic printers, c, which corresponds to the return electrode,
Add a selection signal to io1 to C, 105, and set the recording electrode side to A.
It is divided into a group 20 and eight groups 21 and each 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. FIG. 5 shows the opposing return electrodes 101, for example, E (v).
Figure 7 shows the potential distribution in the current-carrying layer when the recording electrodes 207, 208, and 209 that overlap each other are set to 0 (V) and the others are set to 70-Ting. 0 (v) and there is no potential gradient between each recording electrode, so the current density decreases compared to when recording tK Th is set to 0 (v). Current stops flowing.

As a result, uneven printing of the seal and omissions in printing occur.

In the driving method according to the present invention, 301 to 31 on the recording electrode side
8 and apply signal voltages corresponding to the take to the return electrodes 101 to 105 at the same time, so only one recording electrode is always selected for each return electrode, so the above recording is possible. No electric field leakage occurs between electrodes. As described above, the present invention provides a multi-stylus electrostatic printer and an -fA
&i Although similar, it is a new product based on a completely different driving principle.

Next, gradation recording according to the present invention will be described. The recording electrode 201 and the return path 'ti when the recording head according to the present invention is brought into contact with a heat generating sheet having a current-conducting layer and an ink layer and energized.
The potential distribution of the current-carrying layer due to the L pole 101 is schematically shown in FIG.
Shown in a). There is a very steep gradient of about 1L near the recording electrode. Therefore, the heat distribution of the heat generating sheet due to the heat generated by energization becomes a mountain shape with a peak at the center as shown in (b). The wavy line indicates the case where the input energy is larger than the solid line. In the figure, the vertical axis indicates temperature, and the horizontal axis indicates the position corresponding to figure (a). If Ts is the melting point of the thermofusible ink, the area of the heat distribution cut by Ts 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 is now possible by selecting heat-melting ink for yellow-magenta, cyan, and, if necessary, black.

Here are some examples.

Example 1 An example according to the present invention is shown in No. 81J. In figure (a)!
, = 44 sides, 12 = 0.6 tmrb, /,, =
1 M, recording pitch P2: 200 μm.

Figure (b) shows the shield and plan of the driving method. The division is M=5
0. N-=107', 50 selection signal electrodes S, 50
1~Ss.

350, 2 N+1 = 21 noujJ path electrode 101
~121, N, XM = 5000) 1 pole is driven. Recording 'Electrode II bonding box, starting from the center of pole 101 to the center of pole 121, 10 crn wide with a density of 5 T/M! I:! It is placed. Therefore, as mentioned above, when selecting the selection signal 'electrodes 301 to 325, the 11th electrode is used as 101 and 102, io6 and 1o4.
... When the combinations 119 and 120 are driven together and the selection signal V<poles 326 to 35111 are selected, the return electrodes 102 and 1 (33, 104 and 105, . . .
...It is driven by the combination of 120 and 121. By performing such driving, it was possible to perform normal printing even on recording electrodes arranged between adjacent single-pass electrodes.

FIG. 9 shows a timing chart of drive waveforms.

Selection ID numbers 401 to 4'50 are selection signal electrodes 301 to 3.
50 and at the H level in the figure. (■), the potential is 70-ting at L level. At the timing of the signal 3o, for example, when it is at H level, the return electrodes 1°1 and 1'02,1
03 and 104. ...119 and 120, LL, Bell +
7) The hours are 102 and 105. j04 and 105. ...12
A combination of 0 and 121 is applied as a signal corresponding to the write data.

In this embodiment, 16 gray levels were achieved by varying the pulse width w1v of the voltage applied to the return electrodes 101 to 121 in 16 steps.

FIG. 10 shows an example of a drive circuit. Control section 41
to the image signal generating unit 4o to indicate the beginning of one line f LS signal 61 and request clock s 2 (so.

pvls). The 4-bit pixel data 5o synchronized with the sent request clock 32 is input to the address of the FIOM table 42 for image processing such as gamma correction, and image processing according to each color or output content is performed using a multi-bit signal 51. The pixel data table is selected and transferred to the shift register 44 as 8-bit pixel data 52.

The shift register 44 has 10 stages of 8 bits in parallel, and after the transfer is completed by the transfer clock 33, the preset counter 4
5, the signal 64 is used to make seven strokes 'i'. There are ten preset counters 45 with 8-bit input, which are counted by a clock 53 to create a pulse width according to the input data. A flip-flop 46 is hit with the carry obtained from the cent signal 35 and the preset count to generate a pulse according to the data. As the pulse width modulation is performed as described above, the key is 161P+2+〃・, 256th floor n! 14
You can select the gradation in minute increments.

The obtained variable;';lx pulse is used in the distribution unit 47 to select two adjacent silk alignments of the return electrodes 101 to 121 by the signal 3o.1. , converted into a driving voltage by the driving unit 48 and 21
Return voltages 101 to 121 are output.

On the other hand, selection signals 401 to <SO are generated by a clock 58 and a timing signal 59 in a 5G stage shift register 49, and are outputted from an oven drain high breakdown voltage driver 60 to selection signal electrodes 301 to 650.

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

The energizing heat generating sheet 1 is in the form of a roll, and as shown in FIG. 12, a layer of heat-melting ink is applied in the order of yellow 95, magenta 96, cyan 97 and black 98 for each page. Therefore, to obtain one full-color record, four times of writing are performed. 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 fed back to the roll 80 for electro-hydraulic rotation, and the sheet feed roller 8 for positioning.
2. A signal is sent to the sheet winding killer roller 83 and the recording gutter drive circuit 84.

As described above, the present invention has achieved highly accurate positioning.

FIG. 13 shows an embodiment of the structure of the recording head. The figure is a sectional view perpendicular to the scanning direction of the recording head. Recording using a winding wire, tIIl<201 and the return electrode 201 are held by epoxy resin 601 with excellent heat resistance mixed with quartz glass powder [7, later mounted on the basic ZORO 02 equipped with a drive circuit It is. Recording electrode 20
By using a winding wire in 1, it was possible to manufacture a recording head with good recording electrode dimensions and pinch accuracy. Furthermore, by using an epoxy resin mixed with quartz glass powder, the flatness of the electrode surface can be easily processed, and the heat resistance has also been improved.

FIG. 14 shows another embodiment of the recording head structure.
Ceramic material 603 is used for the holding material around the recording '& PIfi, which is the hottest area on the head surface, so that thermal damage to the head surface due to discharge or overload during recording does not occur.

FIG. 15 also shows another embodiment of the recording head structure, in which pairs of opposing return electrodes are each connected to an insulating substrate 604.6G.
6f-, by etching, and the recording electrode 20
1 is formed on an insulating substrate 605, the respective substrates are pasted together, and then the gaps between the respective substrates are filled with an insulating filler 607.

Since the I-pole is formed by etching, dimensional accuracy can be easily obtained, and the drive circuit can be mounted on the same substrate, making it inexpensive and suitable for mass production. With this, a full color copy of iDcmXIQcm could be made in 20 seconds.

As described above, the present invention realizes the energization heat generation recording method using time-division driving.Moreover, since it is an analog modulation method that applies area modulation depending on the input energy, it is possible to achieve very high resolution, high speed, and full color recording. Achieving a printer at a low price 1. It is groundbreaking. Its applications are extremely wide, including color video printers and color copies.

Embodiment 2 If the driving method according to the present invention is used, a thermal head 95 as shown in FIG. 16 can be constructed. This has a current-carrying layer 96 as a recording head, and the recording principle is exactly the same as that described above. Heat generated by the current-carrying layer 9B melts the thermofusible ink and prints.

Unlike conventional thermal heads, the area is smaller! ! Analog gradation recording using t' scale is possible.

[Brief explanation of the drawing]

Fig. 1 shows the original J (Fig. 11) of the conventional energized heat-generating transfer recording method. Fig. 2 (α) and (b) show the principle diagram of the recording head according to the present invention. Fig. 3 shows the return path. Fig. 4 is a diagram showing the potential distribution of the current-carrying layer due to the electrodes. Fig. 4 is a diagram showing the electrode shape showing the driving principle of the multi-stylus electrostatic printer. Fig. 5 is a diagram showing the driving method of the multi-stylus electrostatic printer. 6A and 6B are diagrams showing the potential distribution in the current-carrying layer when using the recording head according to the present invention, and the temperature distribution in the current-carrying layer. Fig. 7 is a diagram showing the relationship between input energy and printing density in the present invention. Figs. 8(a) and (b) are diagrams showing an outline of a recording head according to an embodiment of the present invention. 9 and 10 are diagrams showing various driving signals and drive circuits. FIG. 11 is a diagram showing a conceptual diagram of the printing apparatus &' according to the present invention. 13 is a diagram showing the energized heating sheet used in the present invention. FIGS. 13, 14, and 15 are diagrams showing the cross-sectional structure of the recording throat of the embodiment of the present invention. FIG. , is a diagram showing a thermal head to which the driving principle according to the present invention is applied. 1. Current-carrying heat-generating sheet 2. Current-carrying layer 4 heat-melting ink 8... Recording papers 101 to 121
・Return electrodes 201 to 250 ・Recording electrodes 307 to 350 ・Selection signal electrodes 501 to 550 ・Backflow prevention +) - diode 42 RO
M table 80... Recording roller 81... Recording head 88... Presser spring 84... Drive circuit 82... Sheet feed roller 86... Sheet winding roller 91... Position detector 90... Positioning controller 601... Ergonomic system 602 - Circuit mounting board 603... Ceramic material 604.605.606... Insulating board IV... 03 □ Figure 6 (α) (b) Figure 8 Figure 9 Figure 11 γ Figure AJ15

Claims (1)

[Scope of Claims] 1. A printing device in which ink is melted by heat generated by electricity and is transferred onto recording paper to obtain a record, the printing device being divided into a plurality of pairs and arranged facing each other. A recording head having a pair of return electrodes, a plurality of recording electrodes arranged between the pairs of return electrodes, and a current-carrying heat generating sheet having a drive circuit, a recording roller, a conductive layer, and a heat-melting ink layer. , sheet feeding roller, sheet winding roller,
A printing apparatus characterized in that the recording head performs time-division driving divided into M, and N recording electrodes are simultaneously driven during one division. 2 The return electrodes are (2N+1) pairs, and the recording electrodes are MXN pairs.
2. The printing device according to claim 1, wherein the printing device is: 6. A patent d characterized in that when the recording electrodes are divided into N groups of M electrodes, each group is arranged so as to face one pair of adjacent path electrodes. . . . The printing device according to item 1. 4 The return path electrode is driven by two adjacent pairs of silk wires 7, and during one sub-scanning period, the return path electrode is driven by (n-1) of the pole pairs.
The printing apparatus V ( o (n == 2.3.4...2N) 5. The printing apparatus according to claim 1, wherein each of the recording 't4i and poles has a backflow prevention diode. The printing device according to claim 1, characterized in that a selection signal is applied to the recording electrode and a data signal is applied to the return path electrode.7 The recording electrode and the return path electrode are made of a hard and flame-retardant material. 2. The printing device according to claim 1, wherein the printing device is held through an insulating material and a throat is used for recording.