JPH0312677A - One-pack developing device - Google Patents

Abstract

PURPOSE:To obtain the image quality equal to the initial image quality even after continuous copying by coating the surface of a toner supplying member with a specific arom. fluorine compd. and biasing this member with 0 to 500V positive potential from a toner transporting member. CONSTITUTION:The surface of the toner supplying member 4 is coated with the arom. fluorine compd. expressed by formula I. This toner supplying member 4 is biased with 0 to 500V potential from the toner transporting member 2. In the formula I, Rf denotes any among -CaF2a-, -OCaF2a-, -CaH2-, -OCaH2a-; X, Y denote positive integers including 0. The positive chargeable toner 6 in a toner tank 7 of a developing section is, therefore, smoothly replenished to the toner supplying member 4, by which the flow of the toner 6 on the toner supplying member is smoothed and the thickness of the toner layer on the toner transporting member 2 is always uniformized. The sharp images which are the same as the initial images are obtd. in this way even after the continuous copying.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a one-component developing device, particularly a one-component developing device for positively chargeable toner.

[Prior Art] Dry developing methods used in electrophotography, electrostatic recording, etc. include a method using a two-component developer consisting of toner and a carrier, and a method using a single-component developer containing no carrier. be. The former method allows relatively stable and good images to be obtained, but it is difficult to obtain constant quality over a long period of time because carrier deterioration and the mixing ratio of toner and carrier tend to fluctuate. Additionally, there are difficulties in maintaining the device and making it more compact. Therefore, the latter method using a one-component developer, which does not have these drawbacks, is attracting attention.

By the way, in this method, the toner (developer) is usually conveyed by at least one toner conveying member, and means for visualizing the electrostatic latent image formed on the latent image carrier by the conveyed toner is provided. It is taken. At that time, it is said that the layer thickness of the toner transported on the surface of the toner transporting member must be made as thin as possible. This applies even when using a two-component developer with a carrier of a very small diameter, and is especially true when using a -component developer and the toner has a high electrical resistance. When used, it is necessary to charge this toner with a developing device, so the toner layer thickness must be made extremely thin. This is because if this layer thickness is large, only the near surface of the toner layer will be charged, making it difficult to charge the entire toner layer uniformly.

In response to these demands, various methods have been proposed as means for regulating the toner layer thickness on the toner transport member (toner layer thickness regulating means), and a typical example is to use a doctor blade and place this blade on the toner transport member. There is a device in which the thickness of the toner layer is controlled by placing them opposite each other and pressing the toner conveyed on the surface of the toner conveying member with a suppressing member (doctor blade).

However, this alone makes it difficult to uniformly transport the toner to the transport member. Therefore, a developing device has been proposed that is rotatably supported in contact with a toner conveying member and has a toner supply means that supplies toner onto the toner conveying member. However, if development is performed continuously, The ability to supply toner to the toner conveying member is reduced, leading to a reduction in image density. There are two reasons for this: a decrease in the ability to replenish toner from the toner hopper to the toner supply member, and a decrease in the ability to replenish toner from the toner supply member to the toner transport member. In order to solve the above-mentioned drawbacks, attempts have been made to add surfactant substances and fluidity modifiers to the toner, but the problem has not yet been solved satisfactorily.

[Problems to be Solved by the Invention] The present invention provides a one-component developing device for electrophotography that forms a thin layer of toner on a toner conveying member and performs development to obtain high-quality images. The objective is to provide a developing device that exhibits no abnormalities and can provide image quality equivalent to the initial image quality.

[Means for Solving the Problems] The configuration of the present invention for solving the above problems is as described in the claims. That is, the present invention
A developing device including at least a toner conveying member, a toner layer thickness regulating member, and a toner supplying member, the toner supplying member being rotatably supported while in contact with the toner conveying member, and supplying toner to the toner conveying member. It is supposed to be done.

After the toner is supplied to the toner supply member, the toner is supplied to the toner transport member, and is further thinned through a toner layer thickness regulating member that regulates the thickness of the toner layer. The latent image is developed by being supplied to the image carrier.

In the present invention, when a positively chargeable toner is used in the above-mentioned developing device, at least the surface of a toner supply member is coated with an aromatic fluorine compound represented by the following general formula, and the toner supply member is charged with a positive voltage of 0 to 500 V from a toner transport member. This method solves the problems of the prior art by using a developing device to which a potential bias is applied.

general formula %formula% any of the X, Y; Positive integers including O.

It is not clear why the problems of the prior art can be solved by coating the above compound, but by coating the toner supply member with the above compound, the positively charged toner in the toner tank of the developing section can be transferred to the toner supply member. Replenishment is smooth. Furthermore, by applying a positive potential bias of 0 to 500 V to the toner supplying member relative to the toner transporting member, the toner flow on the toner supplying member is smoothed, and the toner layer thickness on the toner transporting member is reduced. This is thought to be due to the fact that it can always be kept uniform.

The aromatic fluorine compounds represented by the above general formula used in the present invention include the following.

(1) (4) 1 F3 1 (5) CF Co (6) (2) P3 (7) P3 (3) CF Co (8) CP Co F3 113 CF Co CH Co (9) (lO) P3 (11 ) CP (12) The toner supply member of the present invention may be made of a sponge-like material, a fur brush-like material, etc., but is not limited to these materials. In addition, as a method for coating the surface of the toner supply member with the aromatic fluorine compound, the toner supply member is immersed in a coating liquid obtained by dissolving or dispersing it in a solvent or dispersion medium as necessary, and spraying or brush coating is employed. It is possible to apply by etc.

What is important in the present invention is that the surface of the toner supply member is treated with a substance that shows negative chargeability to the toner. If the material does not show negative chargeability, the toner is removed by the toner supply member. In fact, the toner is not sufficiently charged by friction and the supply member is not sufficiently supplied with toner, and furthermore, the toner is not sufficiently supplied to the toner conveying member, making it impossible to obtain a uniformly charged toner thin layer. What is even more important is that the coating material on the surface of the toner supply member must be stably negatively charged to the toner without changing thermally or over time, even after long-term use. be.

In addition, the toner supply member has a 0 to +50
By applying a bias of 0 V, toner is quickly replenished from the toner supply member onto the toner transport member. If the applied bias is a negative potential, the toner transfer onto the conveying member will be insufficient.1 If it is more than +500V, toner filming will occur on the toner conveying member, and background fogging etc. will occur due to running. occurs on the image.

As the toner used in the developing device of the present invention, substantially all of the toners conventionally used as positively chargeable toners for electrostatic charge development can be effectively used.

That is, both non-magnetic and magnetic toners are used.

Further, the toner is a colored particle in which a colorant is dispersed in a binder resin, and may also contain a dye, a pigment, or a so-called charge control agent to impart charge. Also,
A fluidity improver such as colloidal silica, an abrasive agent such as cerium oxide or silicon carbide, a lubricant such as a metal stearate, a conductivity imparting agent such as tin oxide, etc. may be contained as necessary.

[Example] The present invention will be explained below with reference to Examples. Note that the amounts (parts) of each component described in the Examples are parts by weight.

Example 1 Styrenic resin (D-125 made by Kotsuso Co., Ltd.) 85 parts Carbon black (#44 made by Mitsubishi Carbon Co., Ltd.) 12 parts Nigrosine dye 3 parts After thoroughly stirring and mixing the mixture of the above composition in a Henschel mixer,
The mixture was melt-kneaded using a hot roll mill, cooled to room temperature, coarsely ground using a hammer mill, and then finely ground using an air jet mill. The obtained fine powder was classified to obtain a toner having a particle size of 5 to 25 μm.

Next, the following composition was prepared using a ball mill at room temperature for 10 minutes.
A toner supplying member made of a sponge-like material was immersed in the coating solution obtained by dispersing and dissolving the solution over time, and the solvent was completely evaporated at 110°C.

Exemplary compound (1) 5.0 g Solvent (toluene) aoo f As shown in the drawing, the present toner supply member (sponge roller 4) is used as a developing image consisting of a toner conveying member 2 and a toner layer thickness regulating member (elastic blade 3). installed in the device. To explain the developing method using this developing device, as shown in the figure, the toner 6 contained in the toner tank 7 is forcibly brought to the toner supply member 4 by the stirring blade 5. Supplied.

As the toner supply member rotates in the direction of the arrow, the toner taken into the sponge roller 4 is transported to the toner conveying member 2, where it is rubbed and electrostatically or physically adsorbed. rotate strongly in the direction,
A uniform thin toner layer is formed by the elastic blade 3 and triboelectrically charged. Thereafter, the toner is transported to the surface of the latent image carrier 1 that is in contact with or in close proximity to the toner transport member 2, and the latent image is developed.

In this embodiment, the toner is supplied to the developing device, and the toner conveying member is supplied with -200V, and the toner supply member is supplied with -too much voltage.
A bias of v was applied to develop the negative latent image on the photoreceptor, and a clear image was obtained through a transfer and fixing process. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial ones were obtained.

In addition, a suction type specific charge ffi measuring device that sucks the toner on the toner conveying member through a Faraday cage (not shown) equipped with a filter on the exit side and determines the specific charge of the toner trapped in the Faraday cage by 1111. When we measured the specific charge amount (Q/M) of the toner on the toner conveying member using is +11.
6 (μC/g), which was almost the same as the initial value.

Furthermore, under high temperature and high humidity conditions of 35°Cφ90%RH, and 1
Even in a low-temperature, low-humidity environment of 0° C. and 15% RH, image quality equivalent to that at normal temperature and humidity was obtained.

Note that the frictional charging property between the metal plate surface coated with the coating liquid and the toner is determined by the toner attraction type specific charge ff as described above.
When we applied an i-measuring device to investigate the charge polarity, we found that
The metal plate surface coated with the coating liquid was negatively charged.

Example 2 Styrene-acrylic resin (SBM-73 manufactured by Sanyo Chemical Co., Ltd.) 80 parts Carbon black (#44 manufactured by Mitsubishi Carbon Co., Ltd.) 10 parts Low molecular weight polypropylene 5 parts Quaternary ammonium salt 5 parts A mixture of the above composition was used as Example 1 and A toner was prepared in the same manner. Genuine toner 100
Colloidal silica (R- manufactured by Nippon Aerosil Co., Ltd.)
972) 0.1 part was added.

Next, the following composition was prepared using a ball mill at room temperature for 10 minutes.
A toner supplying member made of a sponge-like material was immersed in the coating solution obtained by dispersing and dissolving the solution over time, and the solvent was completely evaporated at 110°C.

Exemplary compound A-2 + acrylic resin 10 + 20f solvent (
Toluene) A 1000 g toner supply member 4 was placed in the developing device in the same manner as in Example 1. The toner is supplied to the developing device, and the toner conveying member is supplied with -300
A bias of -200 V was applied to the v-toner supply member, and development was carried out in the same manner as in Example 1. When the image was printed out, a clear image was obtained. Subsequently, when 500 sheets were continuously copied, the same clear image as the initial one was obtained.

In addition, the specific charge amount (Q/M) of the toner on the toner conveying member
The initial value is +11.1 (μC/g), which is sufficient, and 500
Q/M after continuous copying of 00 sheets is +10.2 (μC/g)
It remained almost unchanged from the beginning.

Furthermore, 35℃/90%I? Image quality equivalent to that under normal temperature and normal humidity was obtained even under the high temperature and high humidity environment of H and the low temperature and low humidity environment of 10° C. and 15% RH.

Note that the frictional charging property between the metal plate surface coated with the coating liquid and the toner is determined by the toner suction type specific charge Q as described above.
When we investigated the charge polarity by applying an nj constant device, we found that
The metal plate surface coated with the coating liquid was negatively charged.

Example 3 Styrene-2-ethylhexyl acrylate-n-butyl methacrylate resin 80 parts Carbon black (#4
4 Mitsubishi Carbon Co., Ltd.) 12 parts Low molecular weight polypropylene 5 parts Nigrosine dye 3 parts A mixture having the above composition was made into a toner in the same manner as in Example 1. Genuine toner 100
Colloidal silica (R- manufactured by Nippon Aerosil Co., Ltd.)
972) 0.1 part was added.

Next, the following composition was dispersed and dissolved at room temperature for 10 hours using a ball mill to obtain a coating solution. A toner supply member made of a sponge-like material was immersed in this solution, and the solvent was completely evaporated at 110°C.

Exemplified Compound (3) S, or Solvent (Toluene) 300° The toner supply member 4 was placed in the developing device in the same manner as in Example 1. The toner is replenished to the present developing device, and the toner is supplied to the toner conveying member.
A bias of -100 V was applied to the 0 V toner supply member, and development was carried out in the same manner as in Example 1 to produce an image, and a clear image was obtained. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial ones were obtained.

In addition, the specific charge amount (Q/M) of the toner on the toner conveying member
The initial value is +11.8 (μC/g), which is sufficient, and 500
Q/M after continuous copying of 00 sheets is +10.5 (μC/g)
It remained almost unchanged from the beginning.

Furthermore, under high temperature and high humidity conditions of 35°C and 90% RH, and 1
Even in a low-temperature, low-humidity environment of 0° C. and 15% R11, image quality equivalent to that under normal temperature and normal humidity was obtained.

In addition, when we investigated the triboelectricity of the toner and the coating liquid coated on the surface of a metal plate by applying the above-mentioned toner attraction specific charge measuring device, we found that the coating liquid was coated on a metal plate. The material coated on the plate surface was negatively charged.

Comparative Example 1 Images were produced using the same apparatus and toner as in Example 1, except that the coating material in Example 1 was not used as the coating material for the toner supply member 4. Clear images were obtained from the initial stage to continuous copying of 100 sheets. However, after 20,000 sheets, the image density began to decrease, and after 50,000 sheets, the image density further decreased and afterimages occurred.When the toner Q/M on the toner conveying member was measured, the initial +10.2
(807g), +3.2 after 20,000 sheets (807g)
, after 50,000 sheets, it was +1.2 (807 g).

Comparative Example 2 -250V for the same device and toner conveying member as in Example 1
When a similar image was produced by applying a bias of -300V to the toner supply member, a clear image was obtained from the initial stage to continuous copying of too many copies, but after 20
After 1,000 sheets, the image density begins to decrease, and after 50,000 sheets, the image density further decreases, afterimages, etc. occur, and a uniform thin toner layer is not formed on the toner conveying member, and the toner layer thickness regulation Toner filming occurred on the surfaces of the member and the toner transport member.

Further, as in Example 1, the toner Q/Q on the toner conveying member is
When I measured M, the initial value was +11.3 (807g),
It was +5.7 (807 g) after 20,000 sheets, and +2.6 (807 g) after 5,000 G sheets.

Example 4 Exemplified compound (4) was used instead of Exemplified compound (1) of Example 1.
) was used as the covering material for the toner supply member 4, the same equipment and toner as in Example 1 were used, and a bias of -350 V was applied to the toner conveying member, and a bias of -200 V was applied to the toner supply member. When developed and imaged, a clear image was obtained. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial one were obtained.

Also, the specific charge amount (07M) of the toner on the toner conveying member
The initial value is +13.1 (807g), which is sufficient, and 50
Q after 000 sheets continuous copying/old +12.0 (807g
) remained almost unchanged from the beginning.

Furthermore, under high temperature and high humidity conditions of 35°C and 90% RH, and 1
0℃・15%l? ) Image quality equivalent to that under normal temperature and humidity was obtained even under a low temperature and low humidity environment.

In addition, when we investigated the triboelectricity of the toner and the coating liquid coated on the surface of a metal plate by applying the above-mentioned toner attraction specific charge measuring device, we found that the coating liquid was coated on a metal plate. The material coated on the plate surface was negatively charged.

Example 5 Exemplified compound (6) was substituted for Exemplified compound (2) of Example 2.
) was used as the covering material for the toner supply member 4, but the same apparatus and toner as in Example 2 were used, and the toner transport member was coated with -
A bias of -150V was applied to the 300V toner supply member, and development was carried out in the same manner as in Example 2. When an image was formed, a clear image was obtained. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial one were obtained.

In addition, the ratio 7δ load amount of toner on the toner conveying member (07M
) is sufficient at the initial +8.6 (807g), and 500
The Q/M after continuous copying of 00 sheets was +8.1 (807 g), which was almost the same as the initial value.

Furthermore, under high temperature and high humidity conditions of 35°C and 90% RH, and 1
Even in a low-temperature, low-humidity environment of 0° C. and 15% RH, image quality equivalent to that at normal temperature and humidity was obtained.

Note that the frictional charging property between the metal plate surface coated with the coating liquid and the toner is expressed as the toner attraction ratio charge ff as described above.
When we applied an i-measuring device to investigate the charge polarity, we found that
The metal plate surface coated with the coating liquid was negatively charged.

Example 6 Exemplified compound (8) was substituted for Exemplified compound (2) of Example 2.
) was used as the covering material for the toner supply member 4, using the same apparatus and toner as in Example 2, applying a bias of -400 V to the toner conveying member and -200 V to the toner supply member, and developing in the same manner as in Example 2. However, when I took an image, a clear image was obtained. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial one were obtained.

Also, the specific charge amount (07M) of the toner on the toner conveying member
is sufficient at the initial +9.3 (807g), which is 5000
The Q/M after continuous copying of 0 sheets was +8.5 (μctg>, which was almost the same as the initial value.

Furthermore, under high temperature and high humidity conditions of 35°C and 90% RH, and 1
Even in a low-temperature, low-humidity environment of 0° C. and 15% RH, image quality equivalent to that at normal temperature and humidity was obtained.

Note that the frictional charging property between the metal plate surface coated with the coating liquid and the toner is determined by the toner attraction specific charge amount a as described above.
-1 When we applied a constant device to investigate the charge polarity, we found that
The metal plate surface coated with the coating liquid was negatively charged.

Example 7 Exemplified compound (l) was used instead of exemplary compound (1) of Example 1.
O) was prepared using the same apparatus and toner as in Example 1 except that the toner supply member 4 was used as the material, and a bias of 150V was applied to the toner conveying member and 1200V to the toner supply member, and the same as Example 1 was used. When developed and imaged in the same manner, a clear image was obtained. Continue, 5000
When 0 sheets were continuously copied, a clear image was obtained that was the same as the initial image.

In addition, the specific charge amount (G/M) of the toner on the toner conveying member
The initial value is +9.1 (μC/g), which is sufficient, and 5000
The Q/M after continuous copying of 0 sheets was +7.6 (μC/g), which was almost the same as the initial value.

Furthermore, image quality equivalent to that at normal temperature and humidity was obtained even under a high temperature and high humidity environment of 35° C. and 90% R11 and a low temperature and low humidity environment of 10° C. and 15% R1.

Note that the frictional charging property between the metal plate surface coated with the coating liquid and the toner is determined by the toner attraction ratio charge fi as described above.
When the charge polarity was investigated using the all setup, the metal plate surface coated with the above coating liquid was negatively charged.

Example 8 Exemplified compound (1) was substituted for Exemplified compound (1) of Example 1.
2) was used as the coating material for the toner supply member 4, the same equipment and toner as in Example 1 were used, and a bias of -250V to the toner supply member was applied to the toner supply member, and the same as in Example 1 was used. When the film was developed and imaged, a clear image was obtained. Subsequently, when 50,000 sheets were continuously copied, the same clear images as the initial one were obtained.

In addition, the specific charge amount (G/M) of the toner on the toner conveying member
The initial value is +12.1 (μC/g), which is sufficient, and 50
Q/M after 000 sheets continuous copying! Yo+11.2 (μC/
g) was almost unchanged from the initial stage.

Furthermore, image quality equivalent to that under normal temperature and normal humidity was obtained even under a high temperature and high humidity environment of 35° C. and 90% R11 and a low temperature and low humidity environment of 10° C. and 15% RH.

In addition, when we investigated the triboelectricity of the toner and the coating liquid coated on the surface of a metal plate by applying the above-mentioned toner attraction specific charge measuring device, we found that the coating liquid was coated on a metal plate. The material coated on the plate surface was negatively charged.

[Effects of the Invention] By coating the toner supply member with the compound of the present invention, its surface energy is reduced, prevention of toner adhesion and stability over time and environment of frictional charging with toner are improved, and the toner transport member is improved. Improves toner replenishment performance.

Fluorine makes it easier to positively charge the toner, improving the efficiency of triboelectrically charging the toner as a developing device.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing the configuration of an example of the device of the present invention. 1... Electrostatic latent image carrier 3... Elastic blade 5... Stirring blade 7... Toner tank 2... Toner conveying member 4... Sponge roller 6... Toner

Claims (1)

[Scope of Claims] A developing device including at least a toner conveying member, a toner layer thickness regulating member, and a toner supplying member that is freely rotatably supported while in contact with the toner conveying member and supplies toner onto the toner conveying member, At least the surface of the toner supplying member is coated with an aromatic fluorine compound represented by the following general formula, and the voltage is lower than that of the toner transporting member by 0 to 500V.
A single-component developing device for positively chargeable toner, characterized in that a positive potential bias is applied. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ However, Rf; -C_nF_2_n-, -OC_nF_2_n-
, -C_nH_2_n-, -OC_nH_2_n-, X, Y; A positive integer including 0.