JPH0414043A - Powder coating device - Google Patents

Abstract

PURPOSE:To smoothly apply a large amount of 1st powder without making the powder coarse by mixing the 1st powder and 2nd powder which are charged electrostatically to the opposite polarities and scattering them over plain paper in an electric field which has the opposite polarity from the 1st powder. CONSTITUTION:A latent image is formed on photosensitive pressure-sensitive paper 7 which travels between a paper feed roll 5 and a take-up roll 6 and the paper is conveyed to a pressure developing device 3. Further, developer toner S is charged electrostatically and supplied to a carrying roller 22 and plain paper P in a paper feed cassette 18 is conveyed by a guide roller 19 and a conveyor belt 24. A positive high voltage is applied to an electrode roller 23, so the 1st powder (A) of the toner S which is charged electrostatically to the negative polarity is scattered toward the roller 23 and applied over the paper P and the 2nd powder which is charged to the positive polarity, on the other hand, stays at the roller 22 and is returned into a case 20. Then the paper P which is coated with the powder A is conveyed to the device 3 and pressure- developed while superposed on the paper 7 to form a color image on the paper P.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a powder coating device for electrostatically coating charged powder onto a support such as plain paper in image recording, etc. .

[Prior Art] Conventionally, for example, in a color copying machine, microcapsule paper, which is a photosensitive and pressure-sensitive medium, is exposed to light to form a latent image on the microcapsule paper, and this is superimposed on developer paper. A method has been devised in which a color image is formed on developer paper by pressure development.

In such copying machines, the color developer paper used is commercially available color developer paper coated with a color developer in advance. but,
Since using commercially available color developer paper is not versatile, the applicant of this application first developed a color developer that can be easily produced by color copying machine users or by using plain paper, etc. A coating device is proposed, for example, in the specification and drawings attached to the application of Utility Model Application No. 170660/1982.

This device charges developer toner, which has a color developer as its main component, and causes it to be carried on a carrier such as a roller. to face each other in a state. This device generates an electric field between the carrier and the support and applies the developer toner onto the support using the electrostatic force.

[Problems to be Solved by the Invention] However, since the color developer toner has poor charging efficiency, it does not fly in large quantities even if the electric field is strengthened. Furthermore, since the color developer toner has a high cohesive property, its particles tend to adhere to each other to form coarse particles, and the coated surface of the support coated with the color developer toner becomes highly uneven. Therefore, it has been difficult to form high quality images. In order to solve this problem, the present applicant mixes a color developer toner with magnetic particles called a carrier to improve chargeability and fluidity, as shown in the specification and drawings attached to the application, for example, Japanese Patent Application No. 63-333941. We are proposing a color developer application device that improves color properties. However, since the magnetic particles are black or brownish-black, when they are mixed with the developer toner and fly onto the support and are applied,
A problem arises in that even a small amount can seriously damage the image.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a powder coating device that can coat only a first powder in large quantities and smoothly on a support. shall be.

[Means for Solving the Problems] In order to achieve this object, the powder coating device of the present invention has the following features:
A powder case for storing a mixture of a first powder that is charged with positive polarity or negative polarity and a second powder that is charged with a polarity opposite to that of the first powder, and the powder case a carrier for transporting the first and second powders from the substrate to a region where the powders fly toward the support; a support such that the support is charged to a polarity opposite to that of the first powder; and electric field generating means for generating an electric field between the carrier and the carrier.

C Effect: The powder coating device of the present invention having the above configuration is configured such that the first powder and the second powder have opposite charge polarities, so that the first powder and the second powder have opposite charge polarities. By mixing the second powder, the second powder acts to break up the agglomeration of the first powder, and as a result, the mixed powder has excellent fluidity, resulting in coarse particles. It is supported on a carrier without forming a .

Further, since the support is charged with the opposite polarity to the first powder due to the electric field generated by the electric field forming means, an electrostatic attraction force acts between the support and the first powder, and the Only one powder flies toward the support and is coated onto the support.

On the other hand, electrostatic repulsion acts between the second powder and the support,
The second powder does not fly towards the support and is not applied to the support.

[Example] Hereinafter, an example embodying the present invention will be described with reference to FIGS. 1 and 2. First, the configuration of a color image recording apparatus M equipped with a powder coating apparatus to which the present invention is applied will be explained with reference to FIG.

The color image recording apparatus M is broadly divided into an exposure device 1, a powder coating device 2, a pressure developing device 3, and a heat fixing device 4.

An exposure device 1 is provided at the top of a casing C of a color image recording device M. This exposure device 1 includes a halogen lamp 8 that exposes microcapsule paper 7, a rotatable color separation filter 9 for the three primary colors of light, and a rotatable color separation filter 9 located below the halogen lamp 8. and a document table 11 on which a document 10 is placed. Here, a latent image is formed on the microcapsule paper (photosensitive pressure sensitive paper) 7 by exposure.

In the central part of the casing C of the color image recording device M,
A powder coating device 2 is provided. This powder coating device 2
, a carrier roller 22 constituting a carrier, an electrode roller 23 arranged at a predetermined distance from the carrier roller 22, and a conveyor belt 24 that is passed between the electrode roller 23 and the guide roller 25. is provided. The toner case 20 constituting the powder case has the supporting roller 22
It is arranged so that a part of it is located inside it. Then, the carrier roller 22 is grounded, while the electrode roller 2
3 is connected to the positive pole of a DC power supply 26. Further, the negative electrode of the DC power supply 26 is grounded. As a result, a coating electric field is generated between both rollers 22 and 23. This DC power supply 26 constitutes an electric field generating means, and its output voltage is approximately 1 kilovolt. A rotatable supply roller 21 is provided in pressure contact with the circumferential surface of the carrier roller 22 upstream in the rotational direction of the carrier roller 22 from the position of the application area 27 where the carrier roller 22 and the electrode roller 23 oppose each other. ing. Further, inside the toner case 20, a color developer toner S containing a first powder 31 and a second powder 32, which will be described later, are mixed is stored. This developer toner S
is an agitator (
(not shown).

A paper feed cassette 18 is provided on the right side of the powder coating device 2 and stores a plurality of stacked sheets of plain paper P constituting a support. It is inserted into 2. The inserted plain paper P is electrostatically coated with powdered color developer toner S to become color developer paper. The color developing paper discharged from the outlet 28 is conveyed by the guide roller 13, and then superimposed on the microcapsule paper 7 on which the latent image has been formed, and is placed in the pressure developing device 3.
The film is conveyed inside and subjected to pressure development.

A pressure developing device 3 is provided below the exposure device 1 . The microcapsule paper 7 exposed by the exposure device 1 passes through a guide roller 12 and is conveyed into the pressure developing device 3 so as to be overlapped with the color developing paper. The pressure developing device 3 is comprised of a pair of pressure rollers 14 that sandwich the superimposed color developer paper and microcapsule paper 7 and develop them under pressure.

A thermal fixing device 4 is provided on the downstream side of the pressure developing device 3, and the developing paper subjected to pressure development is conveyed to the thermal fixing device 4 by a guide roller 15.

The heat fixing device 4 heats and fixes the recorded image on the color developing paper on which the recorded image has been formed. On the downstream side of the thermal fixing device 4, a guide roller 16 is provided for transporting the color developing paper on which the image has been fixed to the outside of the color image recording device M.

The microcapsule paper 7 is supplied from the paper feed roll 5, passed through each guide roller and the pressure roller 14, and then wound onto the take-up roll 6.

Next, the color developer toner S will be explained with reference to FIG. FIG. 1 is a schematic diagram illustrating the developer toner S.

FIG. 1(a) shows the first powder 31. FIG.

The first powder 31 mainly contains a color developer essential for image formation, specifically, a color developer such as phenol formaldehyde resin, phenolacetylene condensation resin, acidic polymer, and metal salt of aromatic carboxylic acid. Particles with a particle size of 1 to 50 μm that contain wax to improve fixing properties, a charge control agent to adjust chargeability, and additives or lubricants to improve fluidity. It is a powder. Since this first powder 31 has high cohesiveness,
Particles tend to adhere to different areas, forming large secondary particles as a whole. FIG. 1(b) shows the second powder 32 (hatched with diagonal lines to distinguish it from the first powder 31). The second powder 32 is mainly composed of a binder resin used in toner for electrophotographic copying machines, specifically, polystyrene resin, styrene-acrylic copolymer resin, polyester resin, etc., and is charged with an electric charge. A charge control agent for imparting and adjusting properties, an additive for improving fluidity, or a surface treatment agent are added, resulting in transparent particles. The particle size may be in the range of 1 to 200 μm. Since the first powder 31 is charged to a negative polarity, the second powder 32 is adjusted with the charge control agent or the like so that it is easily charged to a polarity opposite to that of the first powder 31, that is, to a positive polarity. ing.

Since this second powder 32 has excellent fluidity, the particles do not adhere to each other and become individual particles. A developer toner S obtained by mixing the first powder 31 and the second powder 32 at room temperature and pressure is shown in FIG. 1(C). Since the particles of the first powder 31 and the particles of the second powder 32 have different charge polarities, they adhere to each other due to electrostatic attraction and form the bonded particles C.
form. At this time, since the particles of the second powder 32 act to break up the agglomeration of the particles of the first powder 31, the bonded particles C do not form coarse secondary particles. In this embodiment, the following color developer toner S is used. The first powder 31 contains zinc salicylate color developer as a main component and has an average particle size of 15 μm. The amount of charge of this first powder 31 on the ferrite carrier is -6 μC/g. The second powder 32 is mainly composed of styrene acrylic resin, and a charge control agent is added thereto so that the second powder 32 is charged with a polarity opposite to that of the first powder 31, that is, so that the ferrite carrier is positively charged. , with a particle size of 100 μm. 50% by weight of the first powder 31 and the second powder 32
A developer toner S is obtained by mixing well at a ratio of . Furthermore, the first
The mixing ratio of the powder 31 and the second powder 32 is not limited to the above ratio, and the mixing ratio of the second powder 32 is 30 to 6
It is sufficient if it is mixed at 0% by weight.

The operation of the color image recording apparatus M configured as above will be explained.

After placing the original 10 on the original table 11, the user presses a start switch (not shown). This starts image recording. First, the No. 10 Gen lamp 8 lights up,
Color correction is performed by rotating the color separation filter 9, and a latent image of the document 10 is formed by exposure on the microcapsule paper (photosensitive and pressure-sensitive paper) 7 running between the paper feed roll 5 and the take-up roll 6. The microcapsule paper 7 exposed by the exposure device 1 is conveyed toward the pressure developing device 3 by a guide roller 12.

On the other hand, the developer toner S is stirred by the agitator and charged. The charged color developer toner S is supplied to the supply roller 21
The developer is supplied to the developer carrying roller 22 by the developer. Then, this charged developer toner S is conveyed to the coating area 27 while being adhered onto the carrier roller 22 . Further, the plain paper P stacked in the paper feed cassette 18 is
9 into the powder coating device 2 through the insertion port 29,
It is transported to the application area 27 by the transport belt 24 .

Here, a positive high voltage is applied to the electrode roller 23 by a DC power supply 26 with respect to the ground.

As a result, a coating electric field is generated in the coating area 27 between the carrying roller 22 and the electrode roller 23. At this time, of the two types of powder constituting the color developer toner S, the first powder 31 is negatively charged, so the electrode roller 23
There is an electrostatic attraction between the two. As a result, the first powder 31 flies toward the electrode roller 23 and is applied onto the plain paper P. On the other hand, since the second powder 32 is positively charged, electrostatic repulsion acts between it and the electrode roller 23 . As a result, the second powder 32 remains on the carrier roller 22 without flying toward the electrode roller 23, and is returned into the toner case 2o by the rotation of the carrier roller 22.

In this way, the first powder 31 whose main component is a developer that contributes to color development among the developer toner S is selectively applied to the plain paper P. In experiments conducted by the applicants, developer toner S was collected from plain paper P coated with developer toner S, and component analysis was performed using an infrared absorption method. 96% by weight of powder 31, second powder 3
2 was 4% by weight.

The plain paper P coated with the color developer S as described above is at the outlet 2.
After being discharged from 8 and conveyed by guide rollers 13 , the microcapsule paper 7 on which the latent image has been formed is overlapped with the microcapsule paper 7 , and then supplied into the pressure developing device 3 . The microcapsule paper 7 and color developer paper P supplied to the pressure developing device 3 are sandwiched between a pair of pressure rollers 14 and subjected to pressure development, and a color image is recorded on the plain paper P. The plain paper P subjected to pressure development by the pressure development device 3 is conveyed to the heat fixing device 4 by the guide roller 15. The color developer paper P is heated by the heat fixing device 4, and the recorded image is fixed onto the color developer paper P.

The plain paper P on which the image has been fixed is further conveyed by a guide roller 16 and discharged to the outside of the color image recording apparatus M.

As detailed above, the color image recording device M of this embodiment
Since a mixture of a negatively charged first powder 31 and a positively charged second powder 32 was used as the developer toner S, the particles of the second powder 32 acts to break off the agglomeration of particles of the first powder 31, and the first powder 3
1 does not aggregate to form coarse particles. Also,
Since a positive high voltage with respect to the ground is applied to the electrode roller 23 by the DC power supply 26, electrostatic attraction acts between the first powder 31 and the electrode roller 23, and only the first powder 31 flies toward the electrode roller 23 and is applied onto the plain paper P. On the other hand, electrostatic repulsion acts between the second powder 32 and the electrode roller 23, so that the second powder 32 remains on the carrier roller 22 without flying toward the electrode roller 23.

Therefore, it is possible to apply only the first powder 31 on the plain paper P in a large amount and smoothly. Moreover, since the second powder 32 is a transparent particle, even if it is applied to some extent on the plain paper P, the image will not be damaged.

The present invention is not limited to the above embodiments, and numerous changes can be made without departing from the spirit thereof.

For example, as shown in FIG. 3, the present invention can be applied to a color image recording apparatus N in which developer toner S is applied to microcapsule paper 7 on which a latent image is formed. still,
The same members as those in the color image recording apparatus M shown in FIG. 1 are given the same numbers, and their explanations will be omitted.

In the color image recording device N, the microcafusel paper 7
runs between the paper feed roll 5 and the take-up roll 6 while contacting the electrode roller 23 of the powder coating device 42 in the middle thereof. Further, the powder coating device 42 is not equipped with the conveyor belt 24 that is passed around the guide roller 25, so that the plain paper P is supplied to the pressure developing device 3 without passing through the powder coating device 42. It is composed of

Then, a latent image corresponding to the original is formed on the microcapsule paper 7 by the exposure device 1. Subsequently, the developer toner S is applied to the microcapsule paper 7 by the electric field existing between the electrode roller 23 and the carrier roller 22. At this time, only the first powder 31 containing a color developer as a main component is applied onto the microcapsule paper 7, as in the case of the color image recording apparatus M. In this way, developer toner S
The microcapsule paper 7 coated with
Therefore, it is sent to the pressure developing device 3. On the other hand, plain paper P is taken out from the paper feed cassette 18 and sent to the pressure developing device by the guide roller 13.

Here, the microcapsule paper 7 coated with the color developer
and plain paper are superimposed and developed under pressure by a pressure roller 14. Here, the capsule-supporting surface of the microcapsule paper 7 is made of PET film and has an extremely smooth surface, but the plain paper P has a rough surface compared to the capsule-supporting surface, so it has poor adhesion with the color developer. Plain paper P is better.

Therefore, the image is transferred to the receiver paper. The image-receiving paper on which the image has been formed in this manner passes through a heat fixing device and is sent out of the device.

In this color image recording apparatus N, the same effects as in the color image recording apparatus M described above can be obtained.

Further, in the above embodiment, the first powder 31 of the developer toner S is negatively chargeable, the second powder 32 is negatively chargeable, but the first powder 31 is positively chargeable. The second powder 32 may be negatively chargeable.

In this case, it is clear that the same effect as in this embodiment can be obtained by connecting the electrode roller 23 to the negative electrode side of the DC power supply 26 and making the electric field in the coating area 27 opposite to that in this embodiment. .

[Effects of the Invention] As is clear from the detailed description above, the present invention provides a powder coating device that can smoothly coat only a large amount of the first powder onto a support. be able to.

[Brief explanation of the drawing]

1 to 3 show embodiments embodying the present invention,
FIG. 1 is a schematic diagram illustrating the developer toner used in the powder coating device of the present invention, FIG. 2 is a schematic diagram of a color image recording device, and FIG. 3 is a diagram showing another embodiment. It is. In the figure, 2 is a powder coating device, 20 is a toner case, 22 is a carrier roller, 26 is a DC power supply, 31 is a first powder, 32
is the second powder, and P is plain paper.

Claims (1)

[Scope of Claims] 1. A powder coating device that electrostatically coats charged powder by flying it onto a support, comprising: a first powder charged to a positive polarity or a negative polarity; a powder case in which a second powder charged with a polarity opposite to that of the first powder is mixed and stored; a carrier for transporting the powder to a region where it flies toward the body, such that the carrier is charged to a polarity opposite to that of the first powder;
A powder coating device comprising an electric field generating means for generating an electric field between a support and a carrier.