JPH0446360A - printer - Google Patents

Abstract

PURPOSE:To form stable dots of high contrast and to obtain a high-speed, quiet printer with a simple structure by uniformly heating a thin layer made of a pyroelectric material and, after destaticization, developing the dots by the use of the reversed polarity electric field generated when the temperature of the layer 2 reaches an ordinary temperature. CONSTITUTION:When the temperature of the thin layer 2 made of the pyroelectric material reaches back to the ordinary temperature in an insulated ink 4, the pyroelectric effect disappears. Consequently, polarization comes back to the original state, and the developed potential comes back to the state of the stand-by time. On the other hand, a latent image part 5 whose potential is adjusted by a stylus head 3 is heated, so that the reversed potential to the above-mentioned generated potential is generated. By the electrostatic attraction, the insulated ink 4 overcomes the hydrophobic force to be attracted to the surface of the thin layer 2 made of the pyroelectric material; thereby development dots are formed. Since the potential is generated at the normal temperature, it is stable. Further, since all the generated charges determined by the dielectric constant of a conductive film can be used for the dot formation, the dots of high contrast can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printer using a pyroelectric material as a latent image forming member.

BACKGROUND OF THE INVENTION In recent years, there has been an increasing demand for printers to be compatible with plain paper, to be faster, and to have lower noise, and a variety of printers have been proposed and commercialized. Among these, laser printers have attracted attention because they are the closest to meeting the above requirements, and are rapidly becoming popular.

However, since laser printers use light, they require a precise optical system and a light shielding structure. Furthermore, the process is complicated, resulting in a complicated structure and requiring high voltage. Furthermore, the constant wear heater consumes a large amount of current. As described above, although laser printers are generally satisfactory in terms of functionality, their complicated structure, large size, high price, long setup time, and difficulty in producing color printers pose major challenges in the future.

Also, JP-A-57-70677, JP-A-60-1
As disclosed in Japanese Patent No. 04965, a printer using a pyroelectric material has been proposed, but it is not satisfactory in terms of speeding up.

Therefore, it is an object of the present invention to solve the structural defects of laser printers while using pyroelectric materials.
Functionally, it supports plain paper and is faster.

The aim is to achieve low noise.

The configuration of a conventional pyroelectric printer will be described below with reference to FIG.

In FIG. 2, a thermosensitive drum 13 is made of a pyroelectric material, and a conductive layer is provided inside the drum and grounded to determine the potential due to the generated charges. 14 is a thermal head,
It is configured linearly to allow line printing. A developing section 15 is arranged close to the thermal head 14 in order to perform development before the spontaneous polarization of the pyroelectric material disappears. 16 is a transfer section, 17 is a fixing section, and 18 is a toner cleaner.

The operation of the conventional pyroelectric printer configured as described above will be described below.

When the pyroelectric material is selectively heated with the thermal head 14, a potential is generated on the surface of the pyroelectric material. The thermal drum 13 rotates,
Before the spontaneous polarization disappears, toner adheres to the heat-sensitive drum 13 in the developing section 15, and after being transferred in the transfer section 16, it is transferred to the fixing section 1.
At step 7, the image is fixed on the recording paper 8 by pressure or heat. The toner remaining on the thermal drum 13 is removed by a toner cleaner 18, and the thermal drum 13 returns to its initial state.

Problems to be Solved by the Invention However, with the above conventional configuration, the temperature of the pyroelectric material cannot be sufficiently raised by the thermal head. This is because ceramic-based pyroelectric materials are difficult to mold thinly, and polymer film-like materials have a low Curie point at which they lose their pyroelectric properties and low thermal conductivity, so they absorb heat from the thermal head. Even if a laser beam is applied from the outside, only the surface temperature of the pyroelectric material rises rapidly, easily exceeding the Curie point, and the internal temperature does not rise. Therefore, it is extremely difficult to generate a potential sufficient to form a latent image using a thermal head or a laser beam in a short period of time by the pyroelectric effect, and it is not easy to increase the speed of image formation.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a small thermal printer that has a simple configuration and is capable of high-speed printing.

Means for Solving the Problems In order to achieve the above object, the present invention provides a thin layer of hydrophobic pyroelectric material on the surface of a conductive drum, and heats the thin layer of pyroelectric material by a heater placed along the thin layer of pyroelectric material. After uniformly heating and generating a -like potential on the surface of the thin layer of pyroelectric material due to the pyroelectric effect, the surface of the thin layer of pyroelectric material is neutralized according to the image pattern using a latent image creation electrode such as a stylus head. After that, the insulating ink is immediately cooled and developed.

Effect of the present invention With the above configuration, the surface of the thin layer of pyroelectric material that is sufficiently heated by the heater generates a higher or lower potential than the surface of the conductive drum on the back side, and the thin layer of pyroelectric material is used as a developing medium. While the temperature is higher than the temperature, the electric potential of the portion corresponding to the image pattern is made closer to the electric potential of the conductive drum on the back side than the electric potential of the portion that is not neutralized by the electric discharge electrode. Then, when the temperature on the thin pyroelectric material layer 2 becomes equal to the temperature of the developing medium, a reverse potential is generated in the portion where the static electricity has been removed, the developing medium is attached, and it can be transferred to paper.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

Example 1 In Figures 1 and 2 (a) and fb), 1 is a conductive drum, and 2 is a thin layer of pyroelectric material coated with a thin film of pyroelectric material on the outer periphery of the rotatable conductive drum 1. , 3 is a stylus head with a plurality of electrodes whose surface is covered with a conductive wear-resistant layer and which lowers the potential of any part of the thin pyroelectric layer 2 to ground, and which contacts the thin layer 2 of pyroelectric material 2 with a low load. are doing. 4 is insulating ink, which also serves to cool the heated thin layer 2 of pyroelectric material. 5 is a latent image formed by the stylus head 3; 6 is attached by the electric potential on the pyroelectric thin layer 2;
This is a developing ink that forms dots. Reference numeral 7 denotes a platen around which a recording paper 8 is wound, and presses the recording paper 8 against the conductive drum 1 so as to be rotatable. Reference numeral 9 denotes an initialization drum having the same potential as the conductive drum 1, which removes the potential remaining on the surface of the pyroelectric thin layer 2 after dot transfer and initializes the potential of the pyroelectric thin layer 2. A far-infrared heater 10 is located near the pyroelectric thin layer 2 and the stylus head 3 and heats the pyroelectric thin layer 2 and the stylus head 3 in a fixed area without contact.

The operation of the printer configured as above will be described below. In the development standby state, no current flows through the far-infrared heater 10 and the thin pyroelectric material layer 2 on the outer periphery of the conductive drum l is not irradiated with far-infrared rays, so the temperature of the thin pyroelectric material layer 2 decreases. remains at room temperature, and no potential is generated on the surface of the thin pyroelectric material layer 2. Therefore, even if the conductive drum 1 is rotated in this state, since the pyroelectric thin layer 2 has hydrophobicity, even if the insulating ink 4 is in contact with it, it will not be able to wet the surface of the pyroelectric thin layer 2. Therefore, the insulating ink 4 does not rise above the surface of the insulating ink 4. During development, a current flows through the far infrared heater 10 and far infrared rays are generated. Since the far-infrared heater 10 is provided along the conductive drum 1, the heating time is secured.
The thin layer of pyroelectric material 2 is sufficiently heated. Polarization occurs in the heated thin pyroelectric material layer 2 due to the pyroelectric effect, and a large potential difference is generated between the surface of the thin pyroelectric material layer on the conductive drum 1 side and the surface on the opposite side. The tip of the weight-relieving electrode of the stylus head 3 is within the heating area of the far-infrared heater 10, and the pyroelectric material thin layer 2
While the temperature of the pyroelectric material thin layer 2 does not decrease, that is, while a large potential difference is generated, the potential of any part of the pyroelectric material thin layer 2 is made equal to the potential of the surface on the conductive drum 1 side.

Further, it is more preferable that the stylus head 3 is heated by another heating at to a temperature higher than the temperature of the thin pyroelectric material layer 2 during static elimination. However, if the temperature of the stylus head 3 during static electricity removal exceeds the Curie point of the pyroelectric thin layer 2, the pyroelectric properties of the pyroelectric thin layer 2 will be lost. It is important that the temperature be higher than the temperature of the thin pyroelectric material layer 2 and lower than the Curie point of the thin pyroelectric material layer 2.

Of course, it goes without saying that the temperature may be lower than the temperature of the pyroelectric thin layer 2 as long as it is within a suitable range for latent image formation.

When the temperature of the pyroelectric thin layer 2 returns to room temperature in the insulating ink 4,
The pyroelectric effect disappears, the polarization returns to its original state, and the generated potential returns to its standby state.

On the other hand, the latent image area 5 whose potential has been adjusted with the stylus head 3 is heated and generates a potential with the opposite sign to the generated potential, and due to the electrostatic attraction, the insulating ink 4 overcomes the hydrophobic force and forms the pyroelectric material thin layer 2. It adheres to the top and forms a development dot. The potential is stable because it is generated at room temperature, and all of the generated charge determined by the dielectric constant of the conductive film can be used for dot formation, so dots with high contrast are formed.

Insulating ink 4 can be attached to any location in the manner described above. The thin pyroelectric material layer 2 used was a 9 μ thick polyvinylidene resin (PVDF) film (manufactured by Kureha Chemical Industry Co., Ltd.) with the physical properties shown in the table below, and a surface potential of 200 μ was generated with a temperature increase of 50 cleg. It was confirmed.

If the amount of temperature increase is less than 20 degrees, the amount of potential generated will be 8 degrees.
In some cases, the voltage is about 0 V or less, and electrostatic charge is not sufficiently generated, and the insulating ink 4 cannot overcome the hydrophobic force, and a developed dot portion cannot be formed on the pyroelectric thin layer 2. 20 again
If the temperature is increased by 0 degree or more, heat will be accumulated in the insulating ink 4 due to continuous development, and the solvent of the insulating ink 4 will evaporate rapidly, leading to an increase in viscosity due to an increase in ink concentration, which will cause scumming, which is not suitable.

The recording paper 8 is lightly pressed against the conductive drum 1 by the platen 7 and is rotating at the same peripheral speed, so the developing ink 6 adheres to and soaks into the synchronously rotating recording paper 8 and is continuously transferred. be exposed. Furthermore, the initializing drum 9 removes the potential remaining on the pyroelectric thin layer 2, making the potential on the surface of the pyroelectric thin layer 2 equal to that of the conductive drum 1.

The heating means is visible light energy (halogen lamp +
It goes without saying that this can also be achieved using a condensing lens), a laser beam, heated gas, etc.

Further, the pyroelectric material can also be realized by a ceramic having pyroelectricity (for example, a piezoelectric element).

Example 2 Another embodiment of the present invention will be described below.

In Fig. 3, 1 is a conductive drum, 2 is a thin layer of pyroelectric material,
3 is a stylus head, 4 is an insulating ink, 5 is a latent image part,
6 is a developing ink, 7 is a platen, 8 is a recording paper, and 9 is an initialization drum, and since these are the same as those in Example 1, their explanation will be omitted. 11 is an insulating heating drum, and 12 is a sliding arm that holds the central axis of the insulating heating drum 11 and slides left and right.

The insulating heating drum 11 is a rotatable metal drum whose outer peripheral surface is coated with a heat-resistant resin such as tetrafluoroethylene resin or polyamide, and an electric heater is provided at the center of the drum.

The operation of the printer configured as above will be described below. In the development standby state, the sliding arm 1
2, the insulating heating drum 11 is not brought into contact with the pyroelectric thin layer 2 on the outer periphery of the conductive drum 1, the temperature of the pyroelectric thin layer 2 remains at room temperature, and there is no potential on the surface of the pyroelectric thin layer 2. It has not occurred. Therefore, even if the conductive drum 1 is rotated in this state, the thin pyroelectric material layer 2 has hydrophobicity, so the insulating ink 4 cannot wet the surface of the thin pyroelectric material layer 2 even if it is in contact with it. Therefore, the insulating ink 4 does not rise above the water surface of the insulating ink 4. During development, the sliding arm 12 lightly presses the insulating heating drum 11 against the thin layer 2 of pyroelectric material. Insulated heating drum 11 for elasticity
heats the pyroelectric thin layer 2 uniformly and sufficiently. The heated thin pyroelectric material layer 2 undergoes polarization due to the pyroelectric effect, and therefore a large potential difference is generated between the surface of the thin pyroelectric material layer 2 on the conductive drum 1 side. While the temperature of the pyroelectric material thin layer 2 does not drop, that is, while a large potential difference is generated, the stylus head 3 makes the potential of any part of the stylus head 3 equal to the potential of the surface on the conductive drum 1 side.

Therefore, when the temperature of the thin pyroelectric material layer 2 in the insulating ink 4 returns to room temperature, the pyroelectric effect disappears, the polarization returns to its original state, and the generated potential returns to its standby state. On the other hand, the latent image portion 5, whose potential has been adjusted with the stylus head 3, is heated and generates a potential with the opposite sign to that generated, and due to the electrostatic attraction, the insulating ink 4 overcomes the hydrophobic force, and the insulating ink 4 is transferred to the pyroelectric material thin layer 2. It adheres to the top and forms a development dot. The potential is stable because it is generated at room temperature, and the generated charge, which is determined by the dielectric constant of the thin layer, can be used for dot formation, resulting in the formation of dots with high contrast.

Insulating ink 4 can be attached to any location in the manner described above. The recording paper 8 is transferred to the conductive drum 1 by the platen 7.
The developing ink 6 adheres to and soaks into the recording paper 8, which is lightly pressed and rotated at the same peripheral speed, and is thus rotating synchronously, and is continuously transferred. Furthermore, the initializing drum 9 removes the potential remaining on the pyroelectric thin layer 2, making the potential on the surface of the pyroelectric thin layer 2 equal to that of the conductive drum 1.

Although the insulating ink 4 was used in the embodiment of the present invention, a chargeable ink (insulating solvent + charged toner) may also be used, and instead of the conductive drum 1, a conductive belt or a conductive coating on an insulating drum may be used. Applied pyroelectric material thin layer 2
It is also possible to realize this by using a device equipped with .

Effects of the Invention As is clear from the above embodiments, the present invention utilizes a conductive drum, a thin layer of hydrophobic pyroelectric material on the surface of the conductive drum, a heater for sufficiently heating the thin layer of pyroelectric material, and a thin layer of pyroelectric material on the surface of the conductive drum. Consisting of multiple static eliminating electrodes that eliminate static electricity from any part, and a chargeable developing medium, the thin layer of pyroelectric material is uniformly heated, and after static electricity removal, development is performed using the reverse polarity electric field that is generated when the temperature is brought to room temperature. It is possible to provide a printer that can form dots with high contrast, has a simple structure, is low cost, and is fast and quiet.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a printer according to an embodiment of the present invention, FIG. 4 is a side sectional view of a conventional pyroelectric printer. 2... Thin layer of pyroelectric material, 3... Stylus head (static elimination electrode), 4... ... Insulating ink (development medium), 7 ... Platen, 8 ... Recording paper, 9 ... Initialization drum, 10 ...
... Far infrared heater (heating means), 11...
Insulating heating drum (heating means). Name of agent Patent attorney Shigetaka Awano and 1 other person

Claims (6)

[Claims] (1) It is composed of a hydrophobic pyroelectric thin layer, a heating means for heating the pyroelectric thin layer, a plurality of static eliminating electrodes for neutralizing any part of the pyroelectric thin layer, and a chargeable developing medium. Featured printers. (2) The printer according to claim 1, wherein the temperature of the thin layer of pyroelectric material is 20° C. to 200° C. higher than the temperature of the developing medium while the static eliminating electrode is eliminating static from the thin layer of pyroelectric material. (3) Claim (1) characterized in that, while the static eliminating electrode is neutralizing the pyroelectric thin layer, the temperature of the static eliminating electrode is higher than the temperature of the pyroelectric thin layer and lower than the Curie point of the pyroelectric thin layer. Printer listed. (4) Claim (1) wherein the pyroelectric thin layer is made of a ferroelectric polymer.
) listed printers. (5) The printer according to claim (1), wherein the thin layer of pyroelectric material is made of ferroelectric ceramic. (6) The printer according to claim (1), wherein the heating means for heating the thin layer of pyroelectric material is an insulating heating drum.