JPH0383085A - Recorder - Google Patents

Abstract

PURPOSE:To eliminate base fogging by applying a signal obtained by converting an electrical signal into a heat signal to a toner carrier containing a heat- friction altering substance on its surface and selectively raising a friction coefficient so that toner attaches to the surface. CONSTITUTION:When a toner roller 1 is rotated and driven counterclockwise, an electric signal is applied to a thermal head 1. Then, a heating part 7 selectively emits heat, and the temperature of the external layer 4 of the facing toner roller 1 rises to raise the friction coefficient for toner T. Namely, the heat signal obtained by converting the electrical signal is applied to the external layer 4 composed of the heat-friction coefficient altering substance to selectively raise the friction coefficient of the surface according to the electric signal. Then, the toner carrying force of this part is improved to attach the toner T in a toner hopper 5. The toner is carried out of the hopper 5 after passing through the top of the thermal head 6. Consequently, only a desirable toner image TI is formed on the toner roller 1 and transferred onto a transfer material 9. Thus, base fogging never occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording device that obtains a recorded image by transferring toner on a toner carrier to a transfer material.

[Problems to be solved by conventional techniques and inventions] The so-called L
Recording apparatuses employing the IST system are well known in the art. Conventional recording devices of this type write electrical signals on a toner layer on the surface of a toner carrier, bring the toner layer into contact with a transfer material, and electrically transfer the toner onto the transfer material to form a predetermined toner image. (For example, Japanese Patent Application Laid-Open No. 55-849
(Refer to the 55% publication).

However, as described above, in conventional recording apparatuses, the toner layer on the toner carrier is brought into direct contact with the transfer material to transfer the toner, so even toner that should not be transferred is transferred to the transfer material by Van der Waertska, etc. However, there is a risk that toner adheres to the background portion of the transfer material where toner should not adhere, resulting in so-called background fog. In order to obtain a high-density toner image, it is necessary to carry multiple layers of toner on a toner carrier, but this causes electrical repulsion between the toners, which tends to cause negative layers and background fog. Become.

Furthermore, as disclosed in JP-A No. 54-47650, conductive magnetic toner is used and magnetic force is used as an auxiliary means in addition to electric diagnosis, resulting in toner images with no background fog and high density. A LIST type recording device has also been proposed, but since the toner used in this recording device is conductive, it cannot be transferred to plain paper, so processed paper is used exclusively as the transfer material. I had to.

Furthermore, when magnetic toner is used, it is difficult to make it colored, and it has been difficult to apply this method to a recording device that forms color toner images.

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording device that is free from background fog, can transfer toner to form a toner image even on plain paper, and can use non-magnetic toner that can be easily colored.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a toner carrier having at least on its surface a heat-friction coefficient converting material that increases the coefficient of friction with respect to toner when heated, and a toner carrier that converts an electrical signal into a thermal signal, a signal converting means for selectively increasing the friction coefficient of the surface of the material in accordance with the electric signal so that the toner adheres to the surface by applying the heat to the friction coefficient converting material; and a toner carrier. The present invention proposes a recording device comprising a transfer means for transferring a toner image formed on a transfer material to a transfer material.

〔Example〕

Hereinafter, five embodiments of the present invention will be described in detail with reference to the drawings.

1 shows an example of a main part of the recording apparatus according to the present invention, in which a donor roller 1 is supported so as to be rotatable in the counterclockwise direction in the figure. The donor roller is composed of a core material 2 made of a conductor such as metal, a conductive rubber layer 3 layered around the core material, and an outer layer 4 laminated around the outer periphery of the core material 2. The outer layer 4 is It is made of a heat-friction coefficient converting material that increases the coefficient of friction against toner when heated. In this example, a copolymer of fluororesin and urethane resin with a weight ratio of 7:3 is used as this material. has a low friction coefficient of 0.5 at room temperature, but if it is heated to a temperature of about 45 degrees, the friction coefficient increases to 1.5. This is a phenomenon that cannot be seen with citane resin alone, and is thought to be caused by the 4# structure change of the resin.

As described above, in this example, the donor roller 1 constitutes an example of a toner carrier having, on at least its surface, a heat-friction coefficient converting substance that increases the coefficient of friction with respect to toner when heated.

The reference numeral 5 in FIG. 1 is a toner hopper that stores toner T, and one side wall of the toner hopper is configured as a thermal head 6 that also serves as a doctor. The tip of the thermal head 6 is in pressure contact with the donor roller 1 and the second thermal head 6 is in pressure contact with the donor roller 1.
As schematically shown in the figure, the donor roller 1 has a large number of heating elements 7 arranged in the axial direction of the roller 1 (direction perpendicular to the plane of the paper in the figure) at the tip facing the surface of the donor roller 1. . The thermal head 6 is the same as those conventionally used in thermal transfer type thermal printers, etc.; each heating section 7 selectively generates heat in response to an electric signal (image signal) applied to the thermal head 6; Exchange electrical signals with thermal signals.

The toner T is a powder consisting of toner particles alone or with additives added thereto.

The donor roller is moved to the first position by an opening device (not shown).
When the toner T in the toner hopper 5 is rotated counterclockwise in the figure and no electric signal is applied to the thermal head 6, the coefficient of friction of the outer layer 4 is low, and the toner T in the toner hopper 5 is heated by the heat applied to the donor roller 1. The head 6 prevents it from exiting the hopper 5.

When an electrical signal is applied to the thermal head 6 and the heat generating section 7 selectively generates heat in response to this signal, the temperature of the portion of the outer layer 4 facing the heat generating section 7 that generates heat rises, and the coefficient of friction against the toner increases. Rise. That is, a thermal signal converted from an electrical signal is transferred to the outer layer 4 made of a heat-friction coefficient converting material.
The friction coefficient of the surface is selectively increased in accordance with the electrical signal. When the friction coefficient of the outer layer 4 increases in this way, the toner conveying force in this area increases, the toner in the toner hopper 5 adheres to this area, and as the donor roller 1 rotates, the tip of the thermal head 6 is It passes through and is carried out of the hopper.

FIG. 2 is a diagram explaining the situation at this time.

What is schematically shown as a circle is toner particles within the toner hopper 5. Assuming that toner particles labeled T1 are present in the outer layer portion 4a of the donor roller l facing the heat generating portion 7 of the thermal head 6, the toner particles T1 have donor particles as shown in FIG. A force Fa directed in the rotational direction of the roller 1 and a force Fb directed into the toner hopper in the opposite direction act. The force Fb is the sum of the adhesion force due to frictional force between toner particles and the conveyance blocking force due to the thermal head 6, and the force Fa is the frictional force between the outside N4 of the donor roller 1 and the toner particle T1, and the force inside the toner hopper 5. This is the sum of the pressing forces caused by other toners present in the toner.

When the heat generating portion 7 is not generating heat, the friction coefficient of the outer layer portion 4a facing it is small, so Fa<Fb, and although the donor roller 1 is rotating, the toner particles T
1 is retained in the toner hopper 5. That is, no toner passes between the thermal head 6 and the donor roller 1.

When the heat-generating portion 7 is energized and generates heat to raise the temperature of the outer layer portion 4a, the coefficient of friction increases, resulting in a force F.
a becomes larger and becomes Fa)Fb.

Therefore, the toner particles T1, or the toner particles located nearby, pass through the thermal head 6 together.

On the surface of the donor roller 1 that has passed through the toner hopper 5 in this manner, a pattern of toner (IITI) is formed as schematically shown in FIG.

The thermal head 6 also functions as a doctor that allows only a predetermined toner to pass through.

Furthermore, when the heat generating section 7 generates heat, the toner particles T1.

Other toner particles near the heat generating part T2. T3. T4 are heated together and become semi-molten, toner particles T1 and other toner particles T2 . T3. It can also be considered that T4 pass together through the thermal head 6 and form the toner image TI.

As mentioned above, toner is attached only to the portion of the donor roller to which a thermal signal is applied by the thermal head 6 and is carried out from the toner hopper 5, so that the surface of the donor roller 1 corresponds to the electrical signal (image signal). Thus, a toner image TI is formed.

On the other hand, as shown in FIG. 1, a conductive transfer roller 8 that is rotated clockwise is placed opposite the donor roller 1, and a transfer material is conveyed between the rollers 1 and 8 in the direction of arrow A. 9
For example, plain paper passes through, and the toner image TI formed on the donor roller 1 is transferred onto the transfer material 9. More specifically, when the toner particles pass through the thermal head 6, the toner particles are triboelectrically charged to a predetermined polarity, in this example negative polarity, due to friction with the thermal head 6. on the other hand.

To the transfer roller 8, a power supply 10 applies a bias voltage having a polarity opposite to the charged polarity of the toner described above (in this example, a positive polarity), and thereby an electric field is formed between both rollers 1 and 8, and the donor roller 1 The upper toner image TI is electrically transferred onto the transfer material 9. To increase this transfer efficiency,
It is preferable to use a toner, especially an electrically insulating toner with high charge retention properties as toner particles, to prevent the charging polarity of the toner from reversing during transfer.

Heat and pressure are applied to the toner image transferred to the transfer material 9 by a fixing device (not shown), and the toner is thermally melted and fixed onto the transfer material, thereby obtaining an R final recorded image.

According to the above configuration, only the toner image TI to be obtained is formed on the donor roller 1 and transferred to the transfer material 9, so that even if the transfer material 9 is brought into direct contact with the surface of the donor roller 1, , background fog does not occur, and high-quality recorded images can be obtained.

Furthermore, since an insulating toner can be used, the toner image TI on the donor roller 1 can be transferred to the transfer material 9 made of plain paper without any problem. In this way, the material of the transfer material 9 can be freely selected.

Furthermore, non-magnetic toners are easy to color because they do not use magnetic force to form toner images.

Alternatively, magnetic toner can also be used for the zero pile, and the configuration according to the present invention can be applied to color recording apparatuses without any problems.

In the experiment, the donor roller 1 with an outer diameter of 20 m was used, the thickness of the conductive rubber layer 3 was 6 m, and the specific volume resistivity was in the 10@Ω range. The donor roller l is driven at a linear speed of 40 m/56 C, and the thermal head 6, which has a doctor function, is heated at 60 g.
/cs of pressure to the surface of the donor roller 1. As a result, when no electric signal is applied to the thermal head 6, the toner in the toner hopper 5 is not carried out to the outside of the hopper.
Further, a toner layer having a thickness of 50 μm could be formed on the donor roller portion corresponding to the heat generating portion 7 to which the electric signal of the thermal head 6 was applied. At this time, the toner in the toner layer is 14
The toner image was frictionally charged to μc/H, and by applying a voltage of +500 V between the donor roller 1 and the transfer roller 8, a toner image could be transferred onto the transfer material 9.

The embodiment shown in FIG. 4 is similar to the previous embodiment in that the thermal head 106 and the doctor 206, which constitutes a part of the toner hopper 5, are constructed from separate members.

A high frictional resistance portion is selectively formed on the outer layer 4 of the donor roller 1 by the thermal head 106 according to an electric signal, and the toner T is placed on the entire surface of the outer layer 4, and the doctor 206 pressed against the donor roller 1 applies the toner T. A scraping action is applied to this toner, and only the toner adhering to the surface of the donor roller with high resistance is allowed to pass under the doctor 206 to form a toner image TI. When the toner passes through the doctor 206, the toner is frictionally charged to a predetermined polarity, and the toner image is electrically transferred onto the transfer material 9 passed between the transfer roller 8 and the donor roller 1. There is no difference from the previous embodiment.

In each of the above-mentioned examples, the heat-friction coefficient conversion material is
Although a fluororesin-urethane resin copolymer was used, other thermoplastic resins such as polyethylene, polypropylene, polybutadiene, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyacrylonitrile, and polyvinyl alcohol were also used. By selectively heating the resin with a thermal head, the resin can be made into a semi-molten state to increase its coefficient of friction, and toner can be attached thereto to form a toner image.

In addition, paraffin wax, microcrystalline wax, polyethylene wax, carnauba wax, and white wax are used as heat-friction coefficient conversion substances.

By using a wax such as beeswax and selectively heating it with a thermal head to lower its viscosity, the coefficient of friction on its surface is increased, and toner can be attached to this surface to form a toner image. It is possible.

Furthermore, in the illustrated embodiment, the electrical signal is converted into a net signal,
This thermal signal is applied to a heat-friction coefficient converting material, and the friction coefficient of the surface of the material is changed so that the toner adheres to the surface.
A thermal head 6.106 was used as a signal converting means for selectively increasing the electrical signal in accordance with the electrical signal, but other means, such as a donor A multi-stylus having a large number of electrode needles arranged in the axial direction of the roller 1 is used, and the electrode needles are energized in response to an electric signal to increase the friction coefficient of the heat-friction coefficient converting material on the surface of the donor roller. It is also possible to use a laser as this signal conversion means, and a specific example thereof is shown in FIG.

The donor roller 1 shown here has an electrically conductive transparent electrode 15.
The transparent electrode 15 is formed into a hollow cylindrical shape, and a laser 11 such as a semiconductor laser is disposed inside the transparent electrode 15. ing.

A laser beam L is emitted from the laser 1 in response to an electric signal (picture signal), and this is transmitted to the outer layer 4 via the transparent electrode 15.
is irradiated and selectively heated to increase the coefficient of friction of its surface. As a result, a toner image TI in a predetermined pattern is formed on the surface of the donor roller 1, and the toner image is transferred onto the transfer material 9 in exactly the same manner as in the previous embodiment.

In this example, one side wall of the toner hopper 5 is
As in the case of FIG. 4, it has the function of a doctor 206, but does not have the function of a thermal head.

In each of the above-mentioned embodiments, the toner is stored in the toner container 5, but for example, tofu is scattered in powder form in the area between the heat exchanger 106 and the doctor 206 shown in FIG. A toner layer is formed by adhering to the donor roller L, and a scraping action is applied to this layer by a doctor 206 to scrape off toner other than the toner adhering to the donor roller portion with a high friction coefficient, thereby forming a toner image T.
I may be formed. Alternatively, a toner layer is formed by flowing the toner and bringing it into contact with the donor roller 1, and this is scraped off with a doctor.

A toner image can also be formed.

In the embodiment shown in FIG. 6, a donor roller 1, which is the same as the donor roller shown in FIG. ing.

The thermal head 106 selectively increases the coefficient of friction of the outer layer 4 of the donor roller 1. On the other hand, toner hopper 10
The toner T contained in the second donor roller 12 is supplied to the entire surface of the second donor roller 12, which rotates clockwise while being in pressure contact with the donor roller 1, and a toner layer is formed thereon. When this toner passes through the doctor 206, it is triboelectrically charged to a predetermined polarity.

When the toner layer on the second donor roller 12 comes into contact with the t-th donor roller 1, the toner moves and adheres to the high friction coefficient portion of the first donor roller 1. In this way,
A predetermined toner image TI is formed on the first donor roller 1 that has passed the second donor roller 12, and this is formed on the transfer material 9.
transcribed into.

In each of the embodiments described above, the transfer roller 8 is used as a transfer means for transferring the toner image formed on the donor roller 1 onto the transfer material 9. However, instead of this, a transfer roller 8 is used as a transfer means for transferring the toner image formed on the donor roller 1 to the transfer material 9. A transfer corona charger or the like may also be used.

〔Effect of the invention〕

As described above, according to the present invention, recorded images with suppressed background blur can be obtained, plain paper can be used as a transfer material, and recording with excellent practicality can be adopted in color recording devices. Equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram showing the main parts of the recording device. FIG. 2 is an explanatory diagram showing the behavior of toner particles. FIG. 3 is an explanatory diagram showing how to act on toner particles. FIGS. 4 to 6 2A and 2B are schematic cross-sectional views showing other embodiments, respectively. 9... Transfer material T... Toner TI... Toner image

Claims (1)

[Claims] a toner carrier having at least on its surface a heat-friction coefficient converting substance whose friction coefficient increases with respect to the toner when heated; , a signal conversion means for selectively increasing the coefficient of friction of the surface of the substance in accordance with the electric signal so that the toner adheres to the surface; and transferring the toner image formed on the toner carrier to the transfer material. A recording device comprising a transfer means.