JPS61100775A - Applying method of toner - Google Patents

Abstract

PURPOSE:To obtain a highly faithful picture stabilized in picture quality by applying an insulating and non-magnetic toner. CONSTITUTION:Magnetic grains are held on a non-magnetic sleeve 49 by magnetic force to form a brush and then the sleeve 49 is rotated, so that toner or a mixture 13 of the toner and the magnetic grains is drawn up by the magnetic brush and contacted and applied with/to a toner carrier 2 to form a uniform toner layer 5. Since the magnetic grains are held on the magnetic roller 48 by the magnetic force, the grains are not transferred to the toner carrier 2. Then, the toner is field from the toner carrier 2 to the surface of an electrostatic image holding body 1 and the gap between the magnetic roller 48 and the toner carrier 2 is adjusted so that the thickness of the toner layer on the toner carrier 2 is about 5-100mu. The gap between the toner carrier 2 and the electrostatic image holding body 1 is set up to a value larger than the thickness of the toner layer and a developing bias voltage may be applied to the toner carrier 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner application method for forming a suitably thin and uniform layer of insulating, substantially non-magnetic toner on a toner carrier.

More specifically, the present invention relates to a toner carrier related to a developing process in which an electrostatic image formed on the surface of an electrostatic image carrier is suitably developed using an insulating and substantially non-magnetic toner. The present invention relates to a toner application method.

Conventional saturation magnetization I Q emn with external magnetic field 5000″6e
Several methods have been proposed for developing toners that can be considered to be substantially non-magnetic, using a -component system. Among these, there is a developer container that stores non-magnetic toner and magnetic particles for toner application, a toner carrier that conveys the toner to the latent image carrier, and a toner carrier that is located upstream of the toner outlet of the developer container. An effective method is to form a thin layer of toner on the toner carrier by placing a magnet forming a magnetic brush made of magnetic particles for toner application in contact with the toner carrier, and to develop the -component.

However, these methods are methods in which insulating non-magnetic toner is carried on a carrier mainly by non-magnetic force in a developing section and developed. The forces are mainly dominated by electrostatic attraction and physical adhesion, and this development method is much more effective than the conventional developing method using insulating magnetic toner, in which the toner is supported on the carrier by the Kuroiso force and electrostatic force. The problem arises. For example, many toners may not be applied relatively thinly and uniformly on the carrier, or even if the toner is applied relatively thinly and uniformly (C), toner may adhere to non-image areas, resulting in so-called smearing. Even if the toner is applied, the amount of toner adhering to the image area is insufficient, resulting in a low-density image.Also, even if most toner is applied thinly and evenly, the fidelity is low, resulting in an extremely poor image with low resolution. In addition, regular insulating non-magnetic toner may cause a decrease in image density or low quality images if used repeatedly, and regular insulating non-magnetic toner may
Environmental changes such as high temperature and high humidity, low temperature and low humidity can sometimes cause a decrease in image density, and other times can cause soil blurring.
L, f“′.

Since e-edge non-magnetic toner has inferior adhesion to the toner carrier compared to magnetic toner, toner spillage due to toner scattering and scraping of a thin toner layer by magnetic particles used for toner application. There was a tendency to discover the phenomenon of

In other words, non-magnetic toner is capable of producing beautiful colors, is inexpensive, and the toner coating method required to obtain a good developed image is difficult to achieve. It has been difficult to apply a coating that stably forms a uniform thin layer over a long period of time.

The present inventors have arrived at the present invention as a result of intensive research aimed at solving various problems.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner application method for applying insulating non-magnetic toner or toner having weak magnetism and which can be considered to be substantially non-emissive, which solves the above-mentioned problems. That is, an object of the present invention is to provide a toner application method that enables development to obtain an image with high fidelity and stable image quality. Another object of the present invention is to provide a toner application method that removes background color and enables development to provide a high-resolution image with uniform density and sufficient density in the image area.

An object of the present invention is to provide a method of applying toner that is excellent in durability, such as a special ratio for continuous reading boxes.

Another object of the present invention is to provide a toner application method that is stable against environmental changes such as high temperature and high humidity, and low temperature and low humidity.

Another object of the present invention is to provide a toner application method for color toners that provides images with sharp hues.

Another object of the present invention is to provide a toner application method that causes less scattering and spillage during development even though the toner is substantially non-magnetic.

More specifically, the object of the present invention is to charge a substantially non-magnetic toner and toner coating magnetic particles to a charge amount T2.

Charge amount T1 of the thin layer toner formed on the toner carrier
A toner (f, yellow) characterized by comprising the steps of: charging the toner so that the amount of charging becomes larger than the charging amount T2; and applying the charged toner in a thin layer onto the carrier. Method fK
: To provide.

In the present invention, the substantially non-magnetic toner is defined by the external magnetic field 50.
This means a toner whose saturation magnetization at 000e is lQemn/ or less.

As a result of studying the toner application method when using non-magnetic toner, the present inventors found that in order to solve the above-mentioned problems, the distance between the toner and the toner carrier is 1.1 t. We have found that it is important to appropriately adjust the balance of electrostatic attraction that acts between magnetic particles.

That is, if the former force is weaker than the latter force, the toner tends to adhere to the magnetic particles, and smooth movement of the toner from the aggregated particle side onto the toner carrier, that is, uniform application is hindered. Even if uniform coating is initially achieved, the strong attractive force from the toner coating magnetic particles causes the toner to gradually be scraped off, resulting in toner spillage and contaminating the inside of the copying machine and the edge image. There, the static attraction between the toner and the toner carrier (the former force).

In other words, the amount of triboelectric charge of the thin layer of toner on the toner carrier is determined by the static attraction between the toner and the magnetic particles for toner application (
In other words, the material and surface properties of the toner carrier are adjusted so that the latter force is greater than the amount of frictional charge between the toner and the magnetic particles.
It becomes necessary to select the material and particle size of the magnetic particles, the material of the toner, etc.

In particular, it is necessary to precisely control the surface conditions of the toner carrier and magnetic particles, which directly affect the charging of the toner. desirable.

On the other hand, if the latter force is significantly lower than the former force,
The movement of the toner from the magnetic particles for toner application onto the toner carrier is extremely fast, and the magnetic particles are unable to carry the next toner in time.
(7) #″9:2-%TJilL,!:!″There is a possibility that a phenomenon in which both images do not appear may occur, so preferably, the friction zone ’TJtt of the thin toner layer on the toner carrier is It is desirable that the amount of frictional electrification is 5 times or less than the amount of frictional electrification with the magnetic particles.

Next, a method for measuring the amount of triboelectric charge in the present invention will be described.

In the present invention, the charge amount of a single layer of toner per unit area on the toner carrier was determined using the so-called suction type Faraday cage method. This suction-type toner is sucked and collected in a filter in the inner cylinder, and from the increase in weight of the filter, it is possible to calculate the number of layers of toner per unit area on the toner carrier. At the same time, by measuring the amount of charge accumulated in an inner cylinder that is electrostatically shielded from the outside, it is possible to determine the amount of charge per unit area on the toner carrier. The suction type Faraday cage method is introduced, for example, in the Journal of the Society of Electrophotography Vol. 1.11.41. From this, the amount of triboelectric charge (Tl) of the thin toner layer on the toner carrier
) can be calculated as the amount of charge per unit weight of toner.

On the other hand, a preferred embodiment 91I for measuring the amount of friction zone 'tIt (abbreviated as T2) between the toner and the magnetic particles will be described with reference to FIG. 3 of the accompanying drawings.

First, a metallic measuring container 6102 having a 400-mesh screen 103 at the bottom is covered with a metal lid 104 containing approximately 41 gold particles of a mixture of toner and magnetic particles whose triboelectric charge is to be adjusted.

Weigh the entire weight of the measurement container 102 at this time W1 (?)
shall be. Next, in the suction device 1o1 (at least the part that follows the measurement container 2 is an insulator), suction is taken from the suction port 107, and the air volume control valve 106 is adjusted to set the pressure of the vacuum gauge 105 to 70 mraH9.

In this state, optical suction (for about 1 minute) is performed to remove the toner. The potential of the -position meter 109 at this time is assumed to be v (volt). Here, 108 is a capacitor and the capacitance is C
(μF'). Also, weigh the entire measurement container after suction. The amount of triboelectric charge of this toner (
μc/1) is calculated using the equation below.

The mixing ratio of toner (1) and magnetic particles (C) (weight ratio = t/C ratio) is expected to vary in actual practice, so toner and magnetic particles with different mixing ratios are prepared in advance. Preferably, the mixture is subjected to tail measurement.

As the binder resin for toner used in the toner application method of the present invention, various material resins conventionally known as toner binder resins for electrophotography are used.

Polystyrene, polystyrene/copolymer, styrene-acrylic copolymer.

Styrenic copolymers such as styrene-acrylic-aminoacrylic copolymers, polyethylene/ethylene copolymers such as polyethylene-vinyl acetate copolymers, polyethylene-vinyl alcohol copolymers, phenolic resins, epoxy-based resin, allyl phthalate resin, polyamide resin.

These include polyester resin, maleic acid resin, etc.

Furthermore, there are no particular restrictions on the manufacturing method of any of the resins.

As the coloring material used in the toner of the present invention, conventionally known coloring materials such as carbon black, dyes, and pigments can be used.

Further, a fluidity improver such as silica or alumina may be added to the toner.

Further, the toner structure described above may be implemented in the core material, the shell material, or both in a microcapsule toner.

The magnetic particles for toner application used in the present invention include, for example, surface oxidized or unoxidized iron, nickel, cobalt,
Metals such as manganese, chromium, rare earths, and alloys or oxides thereof can be used. Also, there are no special restrictions on the backdoor method. As a method for treating magnetic particles, generally a method is used in which a resin, a dye or pigment, a charge control agent, a fluidity control agent, or the like is fixed to the surface of the magnetic particles, either singly or in combination. Fixing method and 1.1 Yu, Kao, 11□1
13. stomach.

A method of at least adhering it to magnetic particles, a method of dissolving or suspending it in a solvent and applying it to the magnetic particles,
Any conventionally published method, such as a method of simply mixing powder, can be applied. Further, similar processing is also possible for the toner carrier.

Magnetic particles and adhesion substances to the surface of the toner carrier vary depending on the toner material, but include, for example, polytetrafluoroethylene, monochlorotrifluoroethylene wood composite, polyvinylidene fluoride, silicone/resin, polyester resin, di-tertiary resin, etc. 8 types of gold vA of butylsalicylic acid, styrene resin, acrylic resin, polyacid.

Polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake.

It is appropriate to use fine silica powder, fine alumina powder, etc. singly or in combination, but the invention is not necessarily limited to this. The amount of the above-mentioned compound to be treated may be appropriately determined so that the magnetic particles meet all the conditions described in FqtI, but in general, the amount of the above compound to be treated with respect to the magnetic particles of the present invention is 0.1 to 3 in total.
0 weight percent (preferably 0.5 to 20 weight percent).For toner carriers, there is no particular restriction on the amount as long as the surface can be uniformly treated, but in general, the average thickness is 0. The thickness is preferably about .1 to 100 μm.

The present invention will be described in detail below based on embodiments with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of the toner application method of the present invention. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 5 is a monocomponent toner, 43 is a developing device, 48 is a magnetic roller, 49 is a non-magnetic sleeve thereof, 50 is a magnet, 52 is a magnetic brush, 13 represents a component toner or a mixture of toner and magnetic particles. By magnetically holding magnetic particles on the non-magnetic sleeve 49 to form a brush and rotating the sleeve 49, the toner or a mixture 13 of toner and magnetic particles is drawn up by the magnetic brush and the toner carrier 2 is drawn up.
A uniform toner layer 5 is formed by applying the toner in contact with the top. At this time, since the magnetic particles are held on the magnetic roller 48 by the output, they do not move onto the toner carrier 2. Next, the toner carrier 2 is statically transferred to the image carrier 1 for pA development.The gap between the magnetic A roller 48 and the toner carrier 2 is set so that the thickness of the toner layer on the toner carrier 2 is approximately 5 to 100μ. Toner carrier 2 and static 4 image carrier l
A developing bias voltage may be applied to the toner carrier 2 so that the gap between the toner and the toner is larger than one layer of toner.

FIG. 2 is a diagram showing another example of the embodiment of the toner application method of the present invention. In the figure, 1 is an electrostatic image carrier, 2 is a toner carrier, 3 is a hopper 16 is a bias power source for development, 5 is mono-component toner, 50 is a fixed magnet, and 52 is a magnet made of a mixture of magnetic particles and toner. A brush 58 indicates a blade for controlling magnetic particle flux nyt. 59 is a magnetic particle circulation regulating member. The magnetic brush 52 formed on the toner carrier 2 is circulated by rotating the toner carrier 2,
The toner carrier 2 takes in the toner in the bar 3.
Then, the toner carrier 2 and the electrostatic image holder 1 are placed against each other with a gap 4 that is thicker than the toner layer, and the one-component toner 5 on the toner carrier 2 is statically coated. tif,
The image is developed by flying onto the static '1u charge image on the lj*hosei 1. The level of the toner layer is controlled by the size of the magnetic brush 52, that is, the amount of magnetic particles, and the regulating blade 58.

The gap between the electrostatic image carrier 1 and the toner carrier 2 may be made larger than the thickness of the toner, and a developing bias may be applied from the bias power source 6.

Hereinafter, the present invention will be explained in more detail based on Examples.

All numbers are for multiple copies unless otherwise noted.

Example 1 0.6 parts of colloidal silica was added to 100 parts of fine particles with an average particle diameter of 1 μm, which were made of 100 parts of styrene-2-ethylhexyl acrylate (Si ÷ 215:5) and 5 parts of a 7-talocyanine backcolor pigment. The externally loaded material was used as a toner. on the other hand.

? Magnetic particles for toner coating were prepared by surface-treating 100 parts of ib, 6 spherical iron powder with a particle size in the range of 150 to 250"7z" with 1 part of silicone resin.

In advance, toner and abrasive particles for toner coating cans were mixed and stirred in various ratios in a polyethylene container, and the amount of friction banding between the toner and magnetic particles for toner coating was measured using the measuring device shown in Figure 3. It was measured. The results are shown in Table 1 and Figure 4.

Ten parts of the toner prepared in Table 1 and 100 parts of magnetic particles for toner application were placed in the developing device shown in FIG. 7 of the attached drawings. The toner carrier 2 is made of aluminum that has been treated with $300 alundum particles to form an uneven surface.
The gap between the magnetic rollers 4 and 8 is approximately 2, and the magnetic brush 5
It was set based on the fact that the maximum thickness of 2 is approximately 3 thicknesses. When the developing device was moved, a uniform thin toner layer of 26 μm was formed on the surface of the toner carrier.

Next, a Canon copier PC-2 equipped with the above developing device.
A copying test was conducted using 0. Incidentally, the gap between the toner carrier 2 and the silent image holder was maintained at 300μ, and the frequency was 1.6 KH as an AC waveform.A DC component of -250V was applied to the peak f of the voltage of 650V in direct direction. 9
00V + 400vt? Gave. The obtained copied image was good, and even after 10,000 copies were made while successively replenishing toner, the image was good, and the thin toner layer on the toner carrier was uniform. Furthermore, there was hardly any toner scattering to the lower part of the developing device. In addition, the environmental conditions of temperature 15℃, humidity 10 and temperature 3
A copying test was conducted under environmental conditions of 5° C. and humidity of 90×RH, and good results were obtained.

In this copying test, the mixing ratio (hereinafter, t/C) of the toner and toner application magnetic particles in the magnetic brush 52 was
ratio) is 11.5/100 to 15/100, and the frictional electrification of the toner and the magnetic particles for toner application is 1tt.
T2 is 4.0 to 5.3 μc/l, and when the triboelectric charge amount T1 of the thin toner layer on the toner carrier is measured by the suction type Faraday cage method, T1 is 12.0 to 15.7.
It was μC151. The value of triboelectric charge Jt T2 is 1-, which is substantially the same as the value on the graph shown in FIG. 4, which was prepared based on the amount of friction band 4 measured using the polyethylene container in Table 1.

This suggests that the amount of triboelectric charge of the toner in the magnetic brush of the developing device can be substituted with the amount of triboelectric charge of the toner measured in another container such as a polyethylene container (7). A similar relationship was observed in Example 2. From the above results, it is found that M triboelectric charging, ITl, and r2 satisfy the following relationship.

T2 <'I't< 4 T2 Comparative Example 1 The same procedure as in Example 1 was carried out except that flat iron powder with a particle size of 150 to 200 mesh, which had not been surface-treated, was used as the magnetic particles for toner application. . In addition, the value measured in the same manner as in Example 1 using a polyethylene G machine was substituted for the friction band 4 discharge T2. The results are shown in Table 2 and Figure 4.

Table 2 The mixing ratio (t/c ratio) of toner and magnetic particles for toner application through the copying test was 14.5/100 to 22/100.
According to FIG. 4, T is -20 to 24 (μC/?).

j On the other hand, the friction band tolerance Tl is +14.3~+
It was 17.5μC/f. Therefore, 4 therapeutic charges tTt
The relationship between Tz and Tz was TI<Tz, and therefore, the toner thickness on the toner carrier was uneven and the layer thickness was extremely thin at 10 μm. The copied image was spotty and poor compared to the original image. moreover,
Toner often spilled to the bottom of the developing device, frequently contaminating images.

Example 2 Comparative Example 1 except that a toner carrier was used in which 100 parts of polystyrene and 10 parts of vinylidene fluoride fine particles were coated on the surface of the toner carrier to give an average film thickness of 10 μm. When all the tests were carried out in the same manner as above, the mixing ratio (r/C ratio) of toner and releasable particles for toner coating was 21.0/100 to 31.8/10 during the copying test and sparing.
0 Teari% From Figure 4, Tz is T2#+19.6~2
2.0 Cttc4). On the other hand, the amount of toner friction zone on the toner carrier is T, = +24.0 to 27
．． 5 (μc/7) te, fz -) taoTl and T
The relationship between the two is 1.5 Tz >'r1> Tz (!
: fx, the toner thin layer on the toner carrier has a layer thickness of 23
μ was uniform, and as a result, good results similar to Amakawa Example 1 were obtained.

Example 3 Toner was prepared by externally adding 0.4 part of colloidal silica to 100 fJ of fine particles with an average particle size of 10 μ, consisting of 100 parts of styrene-butyl methacrylate copolymer, 5 parts of rhodamine red pigment, and 2 parts of chromium salicylate complex. used. On the other hand, amorphous iron powder having a mesh size of 200 to 300, the surface of which was treated with an acrylic resin, was used as magnetic particles for toner application. 20 parts of toner and 100 parts of magnetic particles for toner application are mixed in advance, and the mixture is spread between the regulating blade 58 and the stainless steel toner carrier 2 so that the gap is approximately 2.
Put it into the developing device shown in Figure 2, which is set to have a thickness of 50μ.
The gap between the toner carrier and the D4 image carrier is maintained at 300μ, and a single layer of approximately 80μ of toner is formed on the toner carrier, and the frequency of the AC waveform is 1.6KHz! Peak pressure value ±65
Add DC component +250V to 0V to get the peak voltage +
Applying 900V and -400V to Canon Copy Iso NP
-270, and the same test as in Example 1 was conducted.

The t/c ratio of the magneto-electric blank area 52 in the copying machine is 18.
/100 to 24.5/loO, and the friction band acid amount T1 was -13.1 to -16.3 (μC/f). on the other hand,
For ¥4 amount of chafing = 1+, the values measured in the same manner as in Example 1 using polyethylene volume a were substituted. The results are shown in Table 3 and Figure 5.

43: fc As is clear from the rice milling above, the cylindrical belt, L amount T1 and f
2 has 1 system of Shimoagaki and 1 system.

Tz < Tt <2 Tz The image 'd obtained in the first copy trial was good, with almost no toner scattering or 7"L of magnetic particles for toner application in the first copy.

Comparative Example 2 Silicone (sealed) on 5 sides as +B particles for toner coating cans
Except for using 100 parts of spherical iron powder with a pattern of 100 to 200 mesh, which was processed in 2 parts and 5 parts, the result was 11 in the same way as *Zettai 3. For friction band '1 T2, the value measured in the same manner as in Example 1 using a polyethylene container was substituted. The results are shown in Table 4 and Figure 55.

4th Roasted'1 Meanwhile, set aside in the reconnaissance aircraft 4 t7c, 7) iu
16/□o.

~19.5/100, and the amount of triboelectric charge Tl is -10,
It was 5 to -11.3 (μc/f). therefore,
Friction zone Ii t Tl (!: Tz t(7) Relationship (i, Tx > 5 Tz teal.

The first drawing obtained in the copying test was defective with many υ distortions.
It was a 1Ii statue. This is because the toner cannot be applied onto the toner carrier via the toner coating magnetic particles in accordance with the toner consumption, and a uniform toner cannot be formed on the toner carrier.

Example 4 The same procedure as Comparative Example 2 was conducted except that a toner carrier whose surface was modified to have a polyester resin having an average film thickness of 5 μm was used. The mixing ratio (t/c ratio) with particles is 14.0/100
~18.5/100, and from Figure 5 Tz # -
1.6 to 1.8 (μC/2). Further, the amount of the toner rubbing band 14 on the toner carrier is T□=-3,2 to -6.
, 1 (μc/f), and the relationship between b'rl and Tz is 4'
r, )'L', nT2, resulting in fruit IM example 3
A similar good result was obtained.

[Brief explanation of drawings]

FIGS. 1 to 6S2 are cross-sectional views for explaining a specific example of a developing device used in the developing method related to the toner application method of the present invention. FIG. 3 is a schematic diagram illustrating an apparatus for measuring the magnetic friction band t Tz between a toner and magnetic particles for toner application. FIGS. 4 and 5 are diagrams showing the relationship between the mixing ratio of toner and toner magnetic particles and the amount of triboelectric charge. DESCRIPTION OF SYMBOLS 1... Static one-image holder, 2... Toner carrier, 3...
Hopper, 5...-Component toner, 6... Developing bias power supply, 13...-Component toner or a mixture thereof with magnetic particles, 48... Toner carrier, 49... Non-magnetic Sleeve, 50... Permanent magnet, 52... Magnetic brush, 58... Magnetic particle flux regulation blade, 59...
・Material particle circulation control member.

Claims (1)

[Claims] A step of triboelectrically charging the toner by a substantially non-magnetic toner and magnetic particles for toner application to a charge amount T_2, and a charge amount of the thin layer of toner formed on the toner carrier. A toner application method comprising: charging the toner so that T_i is larger than the charge amount T_2; and applying the charged toner onto the carrier in a thin layer.