JPH0789110A - Method and apparatus for thermal liquefying electrostatic transfer type recording - Google Patents

Abstract

PURPOSE:To apply printing of high image quality to any paper and to realize smooth gradation properties by eliminating a tailing phenomenon and preventing the blur of an image. CONSTITUTION:An ink layer 27 having phase transfer properties or phase transfer and overcooling properties formed on the conductive support 26 of an ink supply feed member 25 is heated corresponding to an image signal by a thermal head 28 and the heated ink layer 27 is subjected to phase transfer corresponding to heating quantity to be liquefied. The ink 33 of the liquefied and charged ink layer 27 is transferred to the recording paper 30 arranged in contact with or in close vicinity to the ink layer 27 by electrostatic attraction due to an electrostatic field using a transfer electric field forming roller before cooled and solidified to form an image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method by heat-sensitive liquefaction electrostatic transfer and a heat-sensitive liquefaction electrostatic transfer type recording apparatus used in copying machines, printers, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, there are a dot printer method, a thermal transfer method, an electrophotographic method, an ink jet method and the like as recording methods used in the fields of copying machines, printers, facsimiles and the like. Each of these methods has merits and demerits, and at the present time, the user side selects and uses them according to the purpose of use. Therefore,
Now, a thermal transfer method will be described as an example of the present invention, which will be described later.

This thermal transfer system uses a thermal head from the back side of a PET (trade name Mylar, scientific name biaxially oriented polyethylene terephthalate) film coated with a solid ink layer of about several microns in which a coloring material is mixed with wax or resin. The image is formed by selectively heating and melting (liquefying) the solid ink in the heated portion, and transferring the solid ink to the paper in contact with the molten portion by adhesive force. In this case, a long head can be easily manufactured (commercially available up to A0 document size), the recording speed is fast, the apparatus is inexpensive and small, and the image density is high. In such a recording method, since the adhesive force between the paper, the molten ink, and the molten inks is stronger than the adhesive force between the base PET film and the molten ink, a phenomenon called “tailing” ( It does not occur that the ink trails beyond the planned range, that is, the place where it should be a circle becomes a tadpole.

In addition to such a thermal transfer system, there are those related to the present invention, which have been technically researched and developed but have not yet been put into practical use.
There are melt transfer recording methods as listed below (4 cases). First, as a first conventional example, as shown in FIG.
There is one disclosed as "Novel Printing Using Polymeric Gel as Ink". Gel-like (eraser-like) ink 2 is attached to the surface of the metal roller 1.
Now, by contacting the recording electrode 3 with the gel-like ink 2,
When a voltage of 0 V is applied and a current is applied, the PH of the ink 2 changes, and as a result, the viscosity drops significantly and changes from gel to sol (syrup). Then, as the metal roller 1 rotates, only the sol ink 2 is selectively transferred onto the paper 5 sandwiched between the metal roller 1 and the transfer roller 4, thereby forming an image. The holes from which the sol-like ink 2 has escaped are uniformly filled between the metal roller 1 and the metal roller 6 having a different peripheral speed. The method using such a sol-like ink requires a small voltage, can be used in an IC circuit, has a high image density, and the image density (gradation) changes depending on the voltage, and the device is simple and the ink is wasted. No use, no need for ink supply for a long time, recording speed 2
It is about 2 mm / sec, which is optimal for a personal printer.

Next, as a second conventional example, there is one disclosed as a "heat control type electrostatic suction slit jet" as shown in FIG. This is 8 heaters / m
The high-resistance mineral oil ink 10 is injected between the thermal head 8 and the slit forming plate 9 (40 μm) arranged side by side, and the suction electrode roller 11 is arranged on the thermal head 8 at a distance of 0.225 mm. Then, the paper 12 is conveyed between the suction electrode roller 11 and the thermal head 8. In this case, when a voltage (160 mW, 1.8 msec) is applied to the selected heater 7, the heat of the peripheral portion increases and the electric resistance and viscosity of the ink 10 in that portion decrease. In this state, the suction electrode roller 11
When a voltage of -2.4 KV is applied to the heater for 0.8 msec, a uniform electric field is formed between the heater 7 and the induction electrode, and uniform electrostatic attraction acts on the induction charges of all the inks 10 in the slits. To do. As a result, the ink 10 rises at the portion where the viscosity is reduced by heating and reaches the paper 12 in the form of pulling a thread. The ink 10 that has arrived penetrates the paper 12 and is printed to form an image.
In such a method, since the thermal head 8 can be used in a nozzleless (slit) shape, the driving method is facilitated, the head portion can be lengthened, and gradation can be obtained depending on the heating amount. become.

Next, as a third conventional example, there is one disclosed as "thermal rheography" as shown in FIG. This is because a semi-solid ink 13 is filled in an ink container 14, an ink passage hole 15 is formed in the center of one end of the ink container 14, and a heating element 16 is arranged in the periphery thereof. A thermal head 17 is attached. Now, when the heating element 16 of the thermal head 17 is energized, the ink 13 near the ink passage hole 15 is heated and melted, and the viscosity is lowered. As a result, the pressure P from above causes the ink 13 to move downward from the ink passage hole 15. Then, recording is performed by adhering to the paper 19 that has flowed out to and held between the platen roller 18 and the paper.

Next, as a fourth conventional example, there is one disclosed as "study on cohesive failure type thermal transfer multiple times process". This is 1 in order to reduce the recording cost.
The present invention relates to research on an ink ribbon that can be used not only once but also many times. As shown in FIG. 6, the ink ribbon 20 has an ink layer 22 provided on one surface of a PET film 21, and the heat-meltable ink layer 22 is cohesively destroyed in the layer during recording. CF because it is a type that partially records by CF
(Cohesive Failure) It is called a ribbon. In this system, the ink layer 22 is configured so that wax islands are formed in the sea of the supercooling material having a large supercooling property.
After heating at 3, the transfer paper 24 is applied, and when the wax is solidified and the supercooling material is peeled off in the liquid state, the ink layer 22 is peeled off from the portion of the supercooling material, and transfer is performed.
As a result, it becomes possible to use it repeatedly a plurality of times. Specifically, the ink layer of a normal ink ribbon has a thickness of several μm, and the entire transfer is completed by one transfer. However, the ink layer 22 is made of a special material and formed as thick as 11 μm. By doing so, it can be used repeatedly 3 to 4 times.

[0008]

In the example of the thermal transfer method as described in the preceding paragraph, the phenomenon of so-called "tailing" does not occur, but the ink ribbon is expensive and difficult to replace. Image remains, no gradation,
On paper with poor smoothness, there is a problem that the contact is bad and the image quality is deteriorated.

Further, in the melt transfer recording method described in the latter part, although the first conventional example to the fourth conventional example have been announced at academic societies and the like, they have not yet been put to practical use. The biggest reason for this is that in each method, the ink that is heated and melted from the solid ink layer that is the base material is transferred to the paper like printing, so that the phenomenon of "tailing" occurs and the image quality This is because the gradation and the gradation are deteriorated.

[0010]

According to a first aspect of the present invention, a phase changeable or phase changeable and supercoolable ink layer formed on a conductive support of an ink supply carrier is heated by a thermal head. It is heated according to the image signal, and the heated ink layer undergoes phase transition according to the amount of heat to be liquefied,
Before the liquefied and charged ink of the ink layer is cooled and solidified, the transfer electric field forming roller is used to transfer the ink onto the recording paper which is in contact with or close to the ink layer by the electrostatic attraction by the transfer electric field. To create an image.

According to a second aspect of the present invention, an ink supply carrier having a phase changeable or phase changeable and supercooling ink layer on a conductive support, and the ink layer of the ink supply carrier. A thermal head that contacts and heats to cause the ink layer to undergo phase transition in accordance with the amount of heat to be liquefied, and the ink of the ink layer that has been liquefied and charged by the thermal head is brought into contact or electrostatically attracted by a transfer electric field. A heat-sensitive liquefaction electrostatic transfer type recording device was constituted by a transfer electric field forming roller for transferring to a recording paper arranged in close proximity.

According to a third aspect of the invention, in the second aspect of the invention, the ink of the ink layer obtained by liquefaction contains a component of a conductive material that can be charged by a transfer electric field.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the charging of the ink of the ink layer is performed by charging the ink in the ink layer before being liquefied or transferred to the recording paper. Means were provided.

According to a fifth aspect of the present invention, in the second aspect of the present invention, after the liquefied ink is transferred, mechanical pressure is applied to the recesses formed on the surface of the ink layer to make them uniform, and the next printing is performed. Before that, an ink layer smoothing means for smoothing the surface of the ink layer was provided.

According to a sixth aspect of the invention, in the second aspect of the invention, the liquefied ink is kept at a temperature higher than the temperature at which the ink is solidified until the thermal head moves from the position to the transfer position. An ink temperature adjusting means was provided.

According to a seventh aspect of the invention, in the second aspect of the invention, the liquefaction range in which the extent and depth of liquefaction of the ink layer is changed by changing the voltage applied to the thermal head or the application time thereof. Adjustment means were provided.

[0017]

According to the first aspect of the present invention, a phase transition type ink, particularly a supercooling type ink, is used, and the ink layer is heated by the thermal head to cause the phase transition to be liquefied. Before the ink was cooled and solidified, it was transferred to the recording paper using the transfer electric field forming roller to create an image, so the ink was separated from the interface between the solid and the liquid and the liquid state was kept stable. As a result, tailing is less likely to occur, which makes it possible to obtain high image quality and gradation, and it is possible to transfer not only in contact but also in non-contact state, and the image does not change due to contact pressure. It can also be used for rough or rough paper.
Furthermore, it is possible to provide an ideal recording method that can perform high-speed printing with a quick start-up and no negative image remaining.

According to the second aspect of the invention, an ink supply carrier having a phase-transition or phase-transition and supercooling ink layer is used, and the ink layer is heated by contacting it with a thermal head. The ink in the liquefied and charged ink layer is transferred to a recording paper which is in contact with or in close proximity by electrostatic attraction by a transfer electric field using a transfer electric field forming roller, by causing a phase transition in accordance with the amount to be liquefied. Since an image is created, tailing is unlikely to occur, and it is possible to provide a device that can obtain high-quality printing at high speed on any paper, and the device itself is small and has a simple structure. It becomes possible to do.

In the third aspect of the present invention, since the ink contains the component of the conductive material that is charged by the transfer electric field, it is not necessary to use a charger required for charging, and the entire ink is charged. It is possible to prevent the occurrence of tailing by applying a force in the direction toward the paper surface to the entire ink at the same time.

According to the fourth aspect of the present invention, it is possible to use an ordinary insulating resin as the base material of the ink by applying the electric charge to the ink by using the charging means.

According to the fifth aspect of the invention, the ink layer smoothing means is used to smooth the surface of the ink layer before the next printing, thereby performing high-speed processing using one ink supply carrier. This makes it possible to create a large number of prints.

In the sixth aspect of the present invention, the liquefied ink temperature adjusting means is used to keep the liquefied ink at a temperature higher than the temperature at which the liquefied ink solidifies until it moves from the position of the thermal head to the transfer position. This makes it possible to prevent the liquefied ink from solidifying.

In the invention according to claim 7, the liquefaction range adjusting means is used to change the voltage applied to the thermal head or the application time thereof to change the liquefaction width and depth range of the ink layer. It is possible to arbitrarily change the amount of ink to be transferred and obtain smooth gradation by one dot multi-value.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention described in claims 1, 2, 4, and 5 will be described with reference to FIG. First, the overall structure of the heat-sensitive liquefied electrostatic transfer recording device (corresponding to the invention of claim 2) will be described. The donor roller 25 as an ink supply carrier is a conductive support roller 26 (which is not limited to such a roller and may be in the form of a belt) as a conductive support located on the inner peripheral side, and this conductive support. Roller 26
And an ink layer 27 formed on the outer peripheral surface of the. As an example, the surface of the conductive support roller 26 made of an aluminum pipe having a diameter of 30 mm and a wall thickness of 5 mm has a thickness of 5 m.
The donor roller 25 can be formed by forming the m ink layer 27. The conductive support roller 2
Although 6 is normally grounded, an electrostatic transfer roller (described later) may be grounded to apply a transfer voltage.
The ink layer 27 has a phase-transition property or a phase-transition property and a supercooling thermal property. Here, a material composed of a supercooling phase-transition wax is used.

Ink layer 2 of such donor roller 25
A thermal head 28 for thermal transfer is provided in contact with the outer peripheral surface of 7. The thermal head 28 heats the ink layer 27 and causes a phase transition in accordance with the amount of heating to obtain a liquefied ink (not shown). An example of the thermal head 28 is a one-line head for writing an image, which has a width of 210 mm and 400 DPI, and the surface of the head is subjected to oil-repellent treatment. In addition,
It may be 600 DPI in consideration of the future.

An electrostatic transfer roller 29 as a transfer electric field forming roller is arranged in contact with the outer peripheral surface of the ink layer 27 of the donor roller 25 on which the thermal head 28 is arranged. Although they are arranged in contact with each other here, they may be arranged in proximity to the ink layer 27 to form a gap. The electrostatic transfer roller 29 forms a transfer electric field for transferring the ink of the ink layer 27 which is liquefied and charged by the thermal head 28 to the transfer paper 30 side as a recording paper. As an example of the electrostatic transfer roller 29, a non-chargeable Teflon-coated SUS round bar having a diameter of 10 mm can be used to be in contact with the ink layer 27 at a light pressure of 10 to 100 g / cm. In this case, the value of the transfer voltage is 50 to 50 in order to transfer the charged liquid ink to the transfer paper 30 by electrostatic attraction.
A voltage of 500V is applied. Further, as the transfer paper 30, since wax ink is used, all papers including OHP paper can be used, and by conveying at 10 to 40 mm / sec, 2 to 8 prints can be made per minute. Can be created.

In addition to this, the present apparatus is provided with a mechanism as described below. A flattening roller 31 as an ink layer smoothing unit is arranged in contact with the outer peripheral surface of the ink layer 27 of the donor roller 25 on which the thermal head 28 and the electrostatic transfer roller 29 are arranged. 5 corresponds to the invention described in 5). After the liquefied ink is transferred to the flattening roller 31, the ink layer 27
Apply mechanical pressure to the recesses on the surface of the
It has a function of smoothing the surface of the ink layer 27 before the next printing. As the flattening roller 31, the same one as the electrostatic transfer roller 29 can be used, the pressing force can be increased, and the flattening roller 31 can be heated and used in some cases.

Thermal head 28 and electrostatic transfer roller 29
And a charger 32 as a charging means at a position close to the outer peripheral surface of the ink layer 27 of the donor roller 25.
Are arranged (corresponding to the invention of claim 4).
The charger 32 has a function of applying an electric charge to the ink of the ink layer 27 to charge the ink before being liquefied or transferred to the recording paper 30 thereafter. In this case, as the charger 32, a corotron, a scorotron (used here), a charging roller, a frictional charging member, for applying a charge to a photoconductor or a toner (not shown) by electrophotography,
All charge injection electrodes and the like can be used. In addition,
In this apparatus as described above, if the temperature of the liquefied ink may drop to the solidification temperature before transfer, it is necessary to add a heating and heat retaining device (not shown).

A recording method by heat-sensitive liquefaction electrostatic transfer using this apparatus with such a configuration will be described (corresponding to the invention of claim 1). In addition, as a recording method in the present embodiment, an ordinary ink 33 (ink 3
A case in which an insulating resin is used as the base material of No. 3) and an electric charge is applied to the ink 33 by the charger 32 arranged around the ink layer 27 will be described.

An ink layer 27 made of a supercooling phase transition type wax is rotated by the donor roller 25 by using a thermal head 28 for each heating element (not shown, this heating element corresponds to a pixel). When heated, the temperature exceeds the liquefaction temperature (T1) at a depth of several μm from the surface of the ink layer 27 within the area of resistance, and the solid ink becomes liquid. At this time,
When the voltage applied to the thermal head 28 or its voltage application time is changed, the volume exceeding the T1 temperature changes in proportion to the voltage or the voltage application time, whereby the density can be changed for each pixel. Next, the surface of the ink layer 27 having the ink 33 liquefied in this way is charged by corona discharge in a non-contact state using the charger 32 of the scorotron. In this case, both the liquefied ink 33 portion and the solid ink portion are charged, but there is no problem because the solid ink portion does not transfer even if the electrostatic attraction of transfer acts. Next, when the thus charged and liquefied ink 33 reaches below the electrostatic transfer roller 29 as the donor roller 25 rotates, the charging polarity of the ink 33 is opposite from the electrostatic transfer roller 29 side. When a polar transfer electric field is applied, the ink 33 charged by electrostatic attraction transfers from the donor roller 25 side to the surface of the transfer paper 30. in this case,
Even if there is a gap between the donor roller 25 and the transfer paper 30, the charged ink 33 can fly and transfer in the gap by electrostatic attraction. Next, the ink droplets thus transferred and adhered to the transfer paper 30 (plain paper) are naturally cooled during the transfer of the transfer paper 30 and solidified below the solidification temperature (Ts). As a result, the desired image has been created. After that, when the liquefied ink 33 is transferred in this manner, the surface of the concave portion generated on the surface of the donor roller 25 is flattened by the flattening roller 31, and the next printing is performed.

As described above, the ink 33 of the phase transition type, in particular, the supercooling type is used, and the ink layer 27 is heated by the thermal head 28 to cause the phase transition to be liquefied, and the liquefied and charging device 32 is used. By transferring the charged ink 33 to the transfer paper 30 using the electrostatic transfer roller 29 before being cooled and solidified, the ink 33 is kept in a stable liquid state and is separated from the interface between the solid and the liquid. For this reason, it is possible to provide a device capable of performing high-quality printing at high speed and achieving high gradation even when the "tailing" unlike in the related art is less likely to occur. In addition, it can be transferred not only in contact but also in non-contact state, and since the image does not change due to contact pressure, it can be used for any paper such as paper of varying thickness or rough paper,
It is possible to provide an ideal recording method that does not start up quickly and leave no negative image. Furthermore, since the ink 33 can be fixed by natural cooling, a fixing device is not required, and the size of the device can be reduced and the structure can be simplified.

Further, in the present embodiment, a normal insulating resin can be used as a base material of the ink 33 by applying an electric charge to the ink 33 using the charger 32. Furthermore, by smoothing the surface of the ink layer 27 using the flattening roller 31 before the next printing, high-speed processing can be performed using one donor roller 25, and a large number of prints can be created. .

Next, an embodiment of the invention described in claim 3 will be described. The description of the same parts as those of the above-described inventions according to claims 1, 2, 4, and 5 is omitted, and the same reference numerals are used for the same parts.

In the above-described embodiment, the case where the recording is carried out by using the ink 33 whose base material is the ordinary insulating resin in the heat-sensitive liquefaction electrostatic transfer type recording apparatus (see FIG. 1) has been described. In the embodiment, the case where a material containing a special component is used as the material of the ink 33 will be described. That is, the ink layer 2 obtained by liquefaction
Ink 33 of No. 7 contained a component of a conductive material that can be charged by a transfer electric field. In general, an ordinary ink 33 that gives an electric charge by using the charger 32 is formed by variously combining a wax composed of ethylbenzenesulfoamide, polyethylene glycol, polyurethane or the like and a colorant composed of nigrosine or the like in various combinations. ing. In this embodiment, a special ink material is formed by adding a chargeable material such as polyethylene oxide or polyaniline as a conductive material to the ink 33 made of such a component. In addition,
Polyethylene oxide is colorless and transparent, but polyaniline has a blue color, so that the ink 33 can be formed without using a coloring agent. Below, special ink 33
Specific configuration examples of the ink formulations 1 to 3 are listed below.

[Ink Formulation 1] Ethylbenzenesulfoamide 70 (parts by weight) (EBSA manufactured by Fujiamide Chemical Co., Ltd.) Nigrosine 3 (parts by weight) Polyethylene oxide (molecular weight 8000) 27 (parts by weight) A powder composition of this formulation was prepared. After mixing, the mixture was heated to 100 ° C. to form the ink layer 27 on the metal substrate. As an initial experiment, a flat ink sheet was prepared instead of the donor roller 25.

[Ink Formulation 2] Ethylbenzenesulfoamide 60 (parts by weight) Polyaniline 35 (parts by weight) Liquid polyurethane 5 (parts by weight) (trade name, Desmophen 670) After mixing the powder composition of this formulation, 100 ° The ink layer 27 was formed on the metal plate by heating to C.

Ink Formulation 3 Ethylbenzenesulfoamide 60 (parts by weight) Polyaniline 20 (parts by weight) Nigrosine 3 (parts by weight) Polyethylene glycol (molecular weight 3000) 17 (parts by weight) N-methylpyrrolidone (solvent) 400 (parts by weight) The term “parts by weight” means weight (wt)%, and a solid content solution of 20 wt% is obtained by using 400 wt% of the solvent. A solution of this formulation was applied on a metal substrate and dried under reduced pressure at 80 ° C to prepare an ink sheet. When the ink sheet thus created was heated at the tip of a thin soldering iron and brought close to a charged film, a part of the film flew and adhered to the film (a charging flight phenomenon due to this electric field will be described later). Similarly, when heated and melted, and the charged film was lightly contacted, the heated portion was transferred to the charged film. In the case of ordinary inks excluding polyaniline and polyethylene oxide, light transfer did not cause the transfer, and even when the transfer occurred, only a part of the transfer occurred.

Next, the charging phenomenon when the ink 33 made of the above-mentioned special material is placed in an electric field will be described. The solid powder used in this charging experiment is
There are two types, polyaniline and polyethylene oxide.
First, the first experimental example will be described. +200 for a 50μm thick mylar film with aluminum vapor deposition on one side
When electrically charged to 0 V and brought closer to 10 mm above the polyaniline powder scattered on the ground plate, the polyaniline powder flew all at once and adhered to the mylar film (the interval was 200 μm).
m flew even at 35V). When the surface potential was measured in that state, it decreased from + 2000V to + 1000V. Also, when charged to -2000 V and brought close to the polyaniline powder, the particles similarly fly and the surface potential of the mylar film is reduced to about half. In this case, the surface potential of the polyaniline powder before flight was measured and found to be + 2V. From this result, it can be seen that the polyaniline powder does not normally have an electric charge, and when it is placed under an electric field, it obtains a large electric charge in both positive and negative directions and fly by an electrostatic force acting on it. The amount of charge at this time was calculated to be 37 μc / g (however, the amount of polyaniline powder deposited on the ground plate was 1.0 mg / cm ³ and the relative permittivity of the Mylar film was 2.1). Such a charge is 1 at + 2000V
It is considered that the electrons induced on the ground plate by the electric field of the Mylar film separated by 0 mm injected electric charges into polyaniline.
Only 0.18 μc / g (however, the spray amount was 1.0 mg / cm ² ). The above-mentioned charging phenomenon of polyaniline due to the electric field also occurred when the polyaniline powder was placed on an insulator such as paper or mylar film, or on the film of polyaniline itself instead of on the conductor. From this, it is understood that the charging phenomenon here is not the phenomenon of charge injection from the electrodes and does not depend on the support.

A second experimental example will be described. Dissolve polyaniline in a solvent and spray coat to a thickness of 1
4, create a polyaniline film layer with an area of 1 μm,
Similar to the first experimental example, a Mylar film charged to +2000 V was brought close to it, but neither moved nor charged. Peel off such a film 1
When a small piece of about 5 mm square was prepared, and a charged mylar film was brought close to the small piece, it flew in a standing state with the edge at the head. The electric potential of the polyaniline film piece which flew in this way and which was flatly attached to the Mylar film was measured and found to be about -200V. From such experimental results, a large amount of electric charges having a polarity different from that of the polyaniline film are generated at the edge of the polyaniline film by an external electric field, and the electrostatic attraction that acts on the electric charge causes the electric charge to fly from the edge and become flat after the adhesion. It is considered that the electric charge spreads over the entire piece of the film and showed a lower potential than that of the powder. This is because a large area of the non-charged portion was pulled and charged only by the charge of the edge. In other words, it is understood that polyaniline only needs to be present in the edge portion to be charged.

From the above two experimental results, the charging mechanism is
An electric field concentrates on the amorphous portion of polyaniline or polyethylene oxide powder, and a large amount of polarization charge is generated, and the charge (electrons) below it is an ion of a different polarity in the very thin film of attached water on the surface of the support. It is considered that (H +) was taken in and neutralized, and only the upper charges (holes) remained to be positively charged. Although the charging phenomenon described here is based on the phenomenon of electric charge flight due to electrostatic attraction, the ink layer 27 and the transfer paper 30 are both used in the above-described two embodiments (see FIG. 1).
Since there is no gap between the inks and the contact transfer is premised, the image width is widened by the electrostatic reaction force between the inks 33 having the same charge in the gap (on the surface of the transfer paper 30). There is no possibility that the landing point of the ink droplet in (1) will be displaced and the position will be displaced from the desired position), and this will not cause image deterioration. Also, in the case of non-contact transfer,
Since electric charges can be applied to the entire ink 33 made of a conductive material by the transfer electric field and a force in the direction perpendicular to the paper surface can be simultaneously applied to the entire ink 33, so-called tailing is less likely to occur. Can prevent image deterioration.

Next, taking the above two experimental examples into consideration, the special chargeable ink 33 as described in the ink recipes 1 to 3 is used, and the ink 33 is formed only by the transfer electric field without the charger 32. The case of charging to form an image will be described with reference to FIG. In addition, here, the charger 32 in FIG.
Shall not exist.

First, when the ink layer 27 of the supercooling phase-change wax is heated for each pixel by the thermal head 28, the temperature is liquefied at a depth of several μm from the surface of the ink layer 27 in the area of resistance. T1) is exceeded, whereby the solid ink is liquefied. Next, when the liquefied ink 33 passes through the position below the thermal head 28 and exits into a free space, it is innumerable in size of 0.1 to 10 μm above the solid ink due to surface tension or the like. Become a small ball. Next, when 33 small spherical ink droplets in the non-charged state reach the position below the electrostatic transfer roller 29, the electrostatic transfer roller 29 causes the 33 electric field ink to have a polarity opposite to that of the transfer electric field. It is charged and transferred from the donor roller 25 to the transfer paper 30 by electrostatic attraction. At this time, the donor roller 2
Even if there is a gap between the sheet 5 and the transfer paper 30, the charged ink 33 flies and is transferred by electrostatic attraction. Next, 33 drops of the ink transferred and attached to the transfer paper 30 are
While the transfer paper 30 is being conveyed, it naturally cools to a temperature not higher than the solidification temperature (Ts) and is firmly fixed to the transfer paper 30, whereby an image is formed. After that, the liquefied ink 33 is transferred, so that the recesses formed on the surface of the donor roller 25 are flattened by the flattening roller 31.

As described above, the ink 33 is made of the material containing the component of the conductive material which is charged by the transfer electric field, so that the use of the charger 32 necessary for charging becomes unnecessary. Further, by giving a charge to the entire ink 33 containing such a special material by the transfer electric field, a vertical force toward the paper surface can be simultaneously applied to the entire ink 33, so that so-called tailing occurs. Can be prevented. Therefore, because of this, it is possible to transfer without causing tailing not only when the transfer paper 30 and the ink layer 27 are in contact, but also in the non-contact state, so that rough paper or transfer paper is transferred. Even if the thickness of 30 is changed, a good image can be obtained without any problem.

Next, an embodiment of the invention described in claim 6 will be described with reference to FIG. It should be noted that description of the same parts as those of the above-described inventions according to claims 1 to 5 is omitted, and the same reference numerals are used for the same parts.

In the heat-sensitive liquefied electrostatic transfer type recording apparatus of FIG. 1, as a thermal characteristic of the ink layer 27 of the donor roller 25, a usual heat-meltable resin (wax) whose viscosity gradually decreases according to the amount of heat is used. It can be used as the ink 33. However, at a certain temperature (liquefaction temperature T1), a solid is suddenly liquefied (phase transition), and even if it is considerably cooled from the liquefied temperature, it remains liquid (supercooling property) and another temperature (solidification temperature Ts). The ink 33 having a thermal characteristic of a type that suddenly returns from a liquid to a solid when it goes down is easy to handle on this apparatus. FIG. 2 shows an example of a change in viscosity with respect to temperature of the supercooling ink 33 having such thermal characteristics.
From FIG. 2, it can be seen that when the temperature rises to 60 ° C., it liquefies suddenly, and when the temperature is gradually lowered from that temperature, it suddenly solidifies at 30 ° C.

Therefore, in this embodiment, in order to effectively utilize the ink 33 having the thermal characteristics as shown in FIG. That is, a liquefied ink temperature adjusting means (not shown) is provided to keep the liquefied ink 33 at a temperature higher than the temperature at which the ink 33 solidifies from the position of the thermal head 28 to the transfer position L. Is. As a result, in the apparatus of FIG. 1, when recording by heat-sensitive liquefaction electrostatic transfer, the liquefied ink temperature adjusting means is used, and the liquefied ink is moved during the movement from the position of the thermal head 28 to the transfer position L. Three
By keeping 3 higher than the solidification temperature T1 at which the ink 33 solidifies, it is possible to prevent the liquefied ink 33 from solidifying, whereby the transfer accuracy can be further improved.

Next, an embodiment of the invention described in claim 7 will be described. It should be noted that the description of the same parts as those of the invention described in claims 1 to 6 is omitted, and the same reference numerals are used for the same parts.

In the heat-sensitive liquefaction electrostatic transfer recording apparatus (see FIG. 1), the ink layer 2 is formed by using the thermal head 28.
In the case where 7 is heated, how much range (width and depth) of the ink layer 27 is liquefied is one key point from the viewpoint of image quality and gradation. Therefore, in the present embodiment, in view of such a point, a liquefaction range adjusting means (FIG. 7) for changing the range and depth of liquefaction of the ink layer 27 by changing the voltage applied to the thermal head 28 or the application time. (Not shown).

By decreasing the voltage applied to the thermal head 28 in contact with the ink layer 27 or shortening the application time to lower the temperature of the thermal head 28, the range of liquefaction area and depth is reduced. As a result, the liquefied volume is reduced. On the contrary, by increasing the voltage applied to the thermal head 28 or increasing the application time, the range of liquefaction width and depth is increased and the liquefaction volume is increased. Using such a phenomenon, printing is performed by changing the range of liquefaction width and depth of the ink layer 27 by changing the voltage or the application time applied to the thermal head 28 by using the liquefaction range adjusting means. It is possible to arbitrarily change the size and density of the pixel, and thus it is possible to realize smooth gradation by one dot (pixel) multivalue.

[0050]

According to the first aspect of the present invention, a phase changeable or phase changeable and supercoolable ink layer formed on a conductive support of an ink supply carrier is subjected to an image signal by a thermal head. By heating, the phase of the heated ink layer is changed according to the amount of heating to liquefy, and the transfer field forming roller is used before the liquefied and charged ink of the ink layer is cooled and solidified. Since an image is created by transferring to a recording paper which is in contact with or close to the ink layer by electrostatic attraction by a transfer electric field, the phase transition type ink is used to transfer an image from the interface between a solid and a liquid. It becomes easy to separate, and the liquid state is kept stable by adopting the supercooling type, so that so-called tailing does not easily occur, thereby improving the image quality and gradation and performing high-speed printing. One in which it is bet. Further, not only can the transfer be performed in a state where the recording paper and the ink layer are in contact with each other as described above, but the transfer can be performed even in a non-contact state, and the image does not change due to the contact pressure. It is possible to provide an ideal recording method that can be used for any kind of paper such as rough paper, and that has a quick start-up and does not leave a negative image.

According to a second aspect of the present invention, there are provided an ink supply carrier having a phase changeable or phase changeable and supercooling ink layer on a conductive support, and the ink layer of the ink supply carrier. A thermal head that contacts and heats to cause the ink layer to undergo phase transition in accordance with the amount of heat to be liquefied, and the ink of the ink layer that has been liquefied and charged by the thermal head is brought into contact or electrostatically attracted by a transfer electric field. Since a heat-sensitive liquefaction electrostatic transfer type recording device was configured with a transfer electric field forming roller that transfers to a recording paper placed in close proximity, so-called tailing is less likely to occur, and high-quality printing on any paper is possible. It is possible to provide a device that obtains at high speed. Also, this eliminates the need for a fixing device,
The device itself can be made small to have a simple structure.

According to a third aspect of the invention, in the second aspect of the invention, the ink of the ink layer obtained by liquefaction is
Since it contains the components of the conductive material that can be charged by the transfer electric field, it is not necessary to use the charger required for charging,
Further, it is possible to prevent the occurrence of tailing by giving a charge to the whole ink and simultaneously applying a force in the direction toward the paper surface to the whole ink.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the charging of the ink of the ink layer is performed by applying an electric charge to the ink in the ink layer before being liquefied or before being transferred to the recording paper. Since the means is provided, a normal insulating resin can be used as the base material of the ink without using a special material.

According to a fifth aspect of the present invention, in the second aspect of the present invention, after the liquefied ink is transferred, mechanical pressure is applied to the recesses formed on the surface of the ink layer to make them uniform, and the next printing is performed. Since the ink layer smoothing means for smoothing the surface of the ink layer is provided before, it is possible to perform high-speed processing using one ink supply carrier, thereby producing a large number of prints and improving work efficiency. Can be increased.

In a sixth aspect of the invention, in the second aspect of the invention, the liquefied ink is kept at a temperature higher than the temperature at which the ink solidifies until the thermal head moves from the position to the transfer position. Since the ink temperature adjusting means is provided, it is possible to prevent the once liquefied ink from being solidified, thereby improving the transfer efficiency and improving the image quality.

According to a seventh aspect of the present invention, in the second aspect of the invention, the liquefaction range in which the range of liquefaction and depth of the ink layer is changed by changing the voltage applied to the thermal head or the application time thereof. Since the adjusting means is provided, it is possible to arbitrarily change the amount of ink to be transferred and obtain smooth gradation by one dot multi-value.

[Brief description of drawings]

FIG. 1 is a front view showing the overall configuration of a heat-sensitive liquefying electrostatic transfer recording apparatus which is an embodiment of the invention described in claims 1, 2, 4, and 5.

FIG. 2 is a characteristic diagram showing how the viscosity of supercooling ink according to an embodiment of the invention of claim 6 changes with temperature.

FIG. 3 is a front view showing a first conventional example.

FIG. 4 is a perspective view showing a second conventional example.

FIG. 5 is a partially cutaway front view showing a third conventional example.

FIG. 6 is a front view showing a fourth conventional example.

[Explanation of symbols]

 25 Ink Supply / Conveyor 26 Conductive Support 27 Ink Layer 28 Thermal Head 29 Transfer Electric Field Forming Roller 30 Recording Paper 31 Ink Layer Smoothing Means 32 Charging Means 33 Ink

Claims (7)

[Claims] 1. A phase-transition or phase-transition and supercooling ink layer formed on a conductive support of an ink supply carrier is heated by a thermal head according to an image signal and heated. The ink layer undergoes a phase transition in accordance with the amount of heat to be liquefied, and before the liquefied and charged ink of the ink layer is cooled and solidified, a transfer electric field forming roller is used to electrostatically attract the ink by the transfer electric field forming roller. A recording method by heat-sensitive liquefaction electrostatic transfer, wherein an image is created by transferring to a recording paper which is in contact with or close to an ink layer. 2. An ink supply carrier having a phase-changeable or phase-transferable and supercooling ink layer on a conductive support, and the ink supply carrier is heated by contacting with the ink layer. A thermal head that liquefies by causing the ink layer to undergo a phase transition in accordance with the amount of heating, and recording paper on which the ink of the ink layer that has been liquefied and charged by this thermal head is brought into contact with or placed close to it by electrostatic attraction by a transfer electric field. A heat-sensitive liquefaction electrostatic transfer type recording device comprising a transfer electric field forming roller for transferring to a recording medium. 3. The heat-sensitive liquefied electrostatic transfer recording apparatus according to claim 2, wherein the ink of the ink layer obtained by liquefying contains a component of a conductive material which can be charged by a transfer electric field. 4. A charging means for charging and charging the ink of the ink layer at a stage before being liquefied or thereafter being transferred to a recording paper.
The heat-sensitive liquefied electrostatic transfer recording device described. 5. An ink layer smoothing method for smoothing the surface of the ink layer before the next printing by applying mechanical pressure to the recesses formed on the surface of the ink layer to make it uniform after the liquefied ink is transferred. 3. The heat-sensitive liquefied electrostatic transfer recording apparatus according to claim 2, further comprising a liquefying means. 6. A liquefied ink temperature adjusting means for keeping the liquefied ink at a temperature higher than the temperature at which the ink is solidified until it is moved from the position of the thermal head to the transfer position. 2. The heat-sensitive liquefied electrostatic transfer recording device according to 2. 7. A liquefaction range adjusting means for changing the extent and depth of liquefaction of the ink layer by changing the voltage applied to the thermal head or its application time. Heat-sensitive liquefaction electrostatic transfer recording device.