JP2008083565A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which allows production of a high-quality image having good gradation of a highlight portion, reduced granularity and roughness, and a uniform gloss comparable to that of a silver salt photograph while maintaining a long lifetime in a full-color copying machine or printer required to achieve high image quality and high speed. <P>SOLUTION: In the image forming method using a two-component developer, development is performed while replenishing a replenisher developer including a toner and carrier to a development unit and carrier which becomes excess in the development unit is discharged from the development unit. The replenisher developer includes the carrier and toner in a specific blending ratio. The two-component developer includes a specific toner prescribed by lightness L<SP>*</SP>in the powder state and a carrier. The carriers have a specific true specific gravity. A transportability index of the replenisher developer satisfies a specific value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method using electrophotography.

  As electrophotographic color image forming apparatuses become widespread, their applications have been diversified and demands on image quality have become stricter. Among the methods for developing electrostatic images using toner, the two-component development method using a two-component developer in which toner is mixed with a carrier is suitable for a full-color copying machine or printer that requires high image quality and high speed. It is used for. In the two-component development method, toner is consumed by development and stays in the developing unit without consuming the carrier. Therefore, carrier contamination occurs due to transfer of the toner component to the carrier, or the carrier itself is subjected to stress in the developing unit. When a coated carrier is used as the carrier, the coating layer is peeled off, which affects the developer characteristics such as chargeability, and the image density fluctuates or fog occurs.

  As a solution to this problem, for example, a carrier is added together with toner consumed by development, and the carrier in the developing unit is replaced little by little, thereby suppressing the change in the charge amount and stabilizing the image density. A developing device is disclosed. (For example, refer to Patent Document 1).

In addition, the use of a replenishment developer containing a carrier and toner having a resistivity higher than the resistivity of the carrier stored in advance in the developing device can maintain chargeability and suppress deterioration in image quality. It is disclosed (for example, see Patent Document 2). Further, it has been disclosed to use a replenishment developer in which a carrier that imparts a higher charge amount to the toner is contained in the toner, to maintain chargeability and to suppress deterioration in image quality (see, for example, Patent Document 3). However, in these methods, since the amount of carriers replaced by the difference in toner consumption differs, and change in resistivity or charge amount of the developer in the developing device, will change in image density is apt to occur, satisfactory It wasn't.

  Further, it has been disclosed to use a replenishment developer containing a magnetic fine particle dispersed resin carrier and a toner to maintain chargeability and suppress deterioration in image quality (see, for example, Patent Document 4). Although this method reduced image density fluctuations and fogging, it was still not satisfactory. Further, in the image forming method using the dark toner and the light toner as described below, a new problem has occurred that the carrier adheres to the image particularly in the light toner.

  On the other hand, copying of images such as photographs, catalogs, and maps is required to reproduce very finely and faithfully, even down to the finest parts. It is desired to extend the color reproduction range. In recent years, especially in the field of printing, where high-definition is required, the electrophotographic method is required to have high definition equal to or higher than the printing quality.

In a recent electrophotographic image forming apparatus using a digital image signal, a latent image is formed by gathering dots of a constant potential on the surface of a latent image carrier, a so-called photoconductor. The tone part and the line part are expressed by changing the dot density. However, in this method, the toner particles are not developed faithfully to the dots, and the toner particles protrude from the dots, and the gradation of the toner image corresponding to the ratio of the black density and the white density of the digital latent image is obtained. The problem of not being able to occur is likely to occur. Furthermore, when the resolution is improved by reducing the dot size in order to improve the image quality, the reproducibility of the latent image formed from minute dots becomes more difficult, and the resolution and particularly the gradation of the highlight area There is a tendency for images to be poor and lack sharpness. Further, irregular dot irregularities are perceived as graininess, which causes a reduction in the image quality of the highlight portion. Such an image has to be said to be inferior when compared with the recent ink jet technology which has been thinned to the silver salt photographic image quality.

In order to improve these, a method has been proposed in which an image is formed using a dark color toner (dark toner) in the solid portion and a lighter toner (light toner) in the highlight portion.
For example, an image forming method for forming an image by combining a plurality of toners having different densities has been proposed (see, for example, Patent Documents 5 and 6). Further, an image forming apparatus has been proposed in which a light color toner having a maximum reflection density less than half of the maximum reflection density of dark toner is combined (see, for example, Patent Document 7). In addition, an image forming apparatus is proposed that combines a dark toner having an image density of 1.0 or more and a light toner having a toner density of less than 1.0 when the toner amount on the recording member is 5 g / m ^2. (See, for example, Patent Document 8). Furthermore, a proposal has been made to improve the image quality by using the magnetic fine particle dispersed resin carrier and the light and dark toner (see, for example, Patent Document 9).
These techniques have improved the image quality of the highlight area. However, when a high image quality such as a photograph is output, a large amount of toner is consumed, so that the carrier and the developer are easily deteriorated. Therefore, further study is necessary to stably output high quality images over a long period of time.
Furthermore, in recent years, electrophotographic image forming apparatuses have begun to be required to have high image quality equivalent to that of silver salt photographs with excellent graininess and glossiness. Here, as a technique for obtaining a color image having excellent glossiness, for example, a color toner image made of a thermoplastic resin is transferred to a recording material provided with a transparent resin layer made of a thermoplastic resin, and the toner image Is fixed on a recording material to make it smooth and glossy. For example, Patent Document 10 is disclosed as such an image forming method. In the image forming method of Patent Document 10, a toner image (toner layer) is embedded in a transparent resin layer of a recording material so that the entire surface of the recording material becomes a smooth surface, and a color image having excellent glossiness is obtained. However, even if high glossiness is obtained, the graininess deteriorates, and further studies are necessary to obtain a high image quality equivalent to a silver salt photograph excellent in graininess and glossiness.

There is a need for a two-component developer and a replenishment developer that can meet today's demanding quality requirements, and further satisfy high image quality, high quality, high speed, and high durability.
Japanese Patent Publication No. 2-21591 Japanese Patent Laid-Open No. 3-145678 Japanese Patent Laid-Open No. 11-223960 JP 2002-258538 A Japanese Patent Laid-Open No. 11-84764 JP 2000-305339 A JP 2000-347476 A JP 2000-231279 A JP 2005-164980 A JP 2004-1108020 A

An object of the present invention is to provide an image forming method capable of solving the above-described problems of the prior art.
That is, the present invention is a full-color copier or printer that requires high image quality and high speed, has a high tone gradation while maintaining a long life, reduces graininess and roughness, and is similar to silver halide photography. An object of the present invention is to provide an image forming method capable of outputting a high-quality image with uniform gloss.
In the present invention, 1) there is no variation in charge distribution, 2) toner scattering from the developing device is minimized, 3) fine lines are not crushed, 4) there is no change in gradation after durable use, and 5). Provide an image forming method that suppresses carrier adhesion on the initial photoreceptor as much as possible, 6) no image density unevenness, 7) no waste of replenishment developer consumption, and 8) prevents color variation in mixed colors. The purpose is to do.

The object of the present invention is achieved by the following. That is,
(1) A first electrostatic image is formed on a first electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component cyan developer. To form a first cyan toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component cyan developer. Forming a second cyan toner image,
The first cyan toner image and the second cyan toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first cyan toner image and a second cyan toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component cyan developer is either a light cyan toner (LC) having a lightness L * in a powder state of 45 <L * ≦ 75 or a dark cyan toner (DC) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component cyan developer contains the other cyan toner and the second carrier,
The first replenishment developer has a lightness L * in a powder state of replenishment light cyan toner (LC) with 45 <L * ≦ 75 or replenishment dark cyan toner (DC) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply cyan toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a transfer index of the replenishment developer containing a replenishment pale cyan toner _(LC) (I LC) and dark cyan toner replenishment _(DC) (I DC) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LC ) <25.0
0.5 <(I _DC ) ≦ 25.0
(I _LC ) <(I _DC )

(2) A first electrostatic image is formed on the electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component cyan developer. One cyan toner image,
A second electrostatic image is formed on the electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component cyan developer, and the second electrostatic image is developed. Forming a cyan toner image,
The first cyan toner image and the second cyan toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first cyan toner image and a second cyan toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component cyan developer is either a light cyan toner (LC) having a lightness L * in a powder state of 45 <L * ≦ 75 or a dark cyan toner (DC) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component cyan developer contains the other cyan toner and the second carrier,
The first replenishment developer has a lightness L * in a powder state of replenishment light cyan toner (LC) with 45 <L * ≦ 75 or replenishment dark cyan toner (DC) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply cyan toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a transfer index of the replenishment developer containing a replenishment pale cyan toner _(LC) (I LC) and dark cyan toner replenishment _(DC) (I DC) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LC ) <25.0
0.5 <(I _DC ) ≦ 25.0
(I _LC ) <(I _DC )

(3) The image forming method as described in (1) or (2) above, wherein (I _LC ) and (I _DC ) satisfy the following formula.
0 <(I _DC ) − (I _LC ) ≦ 10.0

(4) Carrier / toner mass ratio (C / T (LC)) of the light cyan toner (LC) and the replenishment developer containing the carrier, replenishment containing the dark cyan toner (DC) and the carrier (1) to (3), wherein the carrier / toner mass ratio (C / T (DC)) of the developer for toner is (C / T (LC)) <(C / T (DC)) The image forming method according to any one of the above.

(5) A first electrostatic image is formed on the first electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component magenta developer. To form a first magenta toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component magenta developer. Forming a second magenta toner image,
Transferring the first magenta toner image and the second magenta toner image to a transfer material with or without an intermediate transfer member;
An image forming method for fixing a first magenta toner image and a second magenta toner image on a transfer material by using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component magenta developer is either a light magenta toner (LM) having a lightness L * in the powder state of 45 <L * ≦ 75 or a dark magenta toner (DM) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component magenta developer contains the other magenta toner and the second carrier;
The first replenishment developer is a replenishment light magenta toner (LM) with a lightness L * in the powder state of 45 <L * ≦ 75 or a replenishment dark magenta toner (DM) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply magenta toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light magenta toner transfer index of the replenishment developer containing the _(LM) (I LM) and dark magenta toner replenishment _(DM) (I DM) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LM ) <25.0
0.5 <(I _DM ) ≦ 25.0
(I _LM ) <(I _DM )

(6) A first electrostatic image is formed on the electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component magenta developer. One magenta toner image,
A second electrostatic charge image is formed on the electrostatic image carrier, and the second electrostatic charge image is developed using a second developer containing a second two-component magenta developer, Forming a magenta toner image,
Transferring the first magenta toner image and the second magenta toner image to a transfer material with or without an intermediate transfer member;
An image forming method for fixing a first magenta toner image and a second magenta toner image on a transfer material by using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component magenta developer is either a light magenta toner (LM) having a lightness L * in the powder state of 45 <L * ≦ 75 or a dark magenta toner (DM) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component magenta developer contains the other magenta toner and the second carrier;
The first replenishment developer is a replenishment light magenta toner (LM) with a lightness L * in the powder state of 45 <L * ≦ 75 or a replenishment dark magenta toner (DM) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply magenta toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light magenta toner transfer index of the replenishment developer containing the _(LM) (I LM) and dark magenta toner replenishment _(DM) (I DM) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LM ) <25.0
0.5 <(I _DM ) ≦ 25.0
(I _LM ) <(I _DM )

(7) The image forming method according to (5) or (6), wherein (I _LM ) and (I _DM ) satisfy the following formula:
0 <(I _DM ) − (I _LM ) ≦ 10.0

(8) Carrier / toner mass ratio (C / T (LM)) of the light magenta toner (LM) and the replenishment developer containing the carrier, replenishment containing the dark magenta toner (DM) and the carrier (5) to (7), wherein the carrier / toner mass ratio (C / T (DM)) of the developer for toner is (C / T (LM)) <(C / T (DM)) The image forming method according to any one of the above.

(9) A first electrostatic image is formed on the first electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component black developer. To form a first black toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component black developer. Forming a second black toner image,
The first black toner image and the second black toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first black toner image and a second black toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component black developer is either a light black toner (LK) with a lightness L * in a powder state of 20 <L * ≦ 55 or a dark black toner (DK) of 0 ≦ L * ≦ 20. Contains one and the first carrier,
The second two-component black developer contains the other black toner and the second carrier,
The first replenishment developer is a replenishment light black toner (LK) having a lightness L * in a powder state of 20 <L * ≦ 55 or a replenishment dark black toner (DK) having 0 ≦ L * ≦ 20. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply black toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light black toner _(LK) (I LK) and the transfer index of the replenishment developer containing the deep black toner replenishment _(DK) (I DK) satisfies the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LK ) <25.0
0.5 <(I _DK ) ≦ 25.0
(I _LK ) <(I _DK )

(10) A first electrostatic charge image is formed on the electrostatic charge image carrier, and the first electrostatic charge image is developed using a first developer containing a first two-component black developer. One black toner image,
A second electrostatic image is formed on the electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component black developer, Forming a black toner image,
The first black toner image and the second black toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first black toner image and a second black toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component black developer is either a light black toner (LK) with a lightness L * in a powder state of 20 <L * ≦ 55 or a dark black toner (DK) of 0 ≦ L * ≦ 20. Contains one and the first carrier,
The second two-component black developer contains the other black toner and the second carrier,
The first replenishment developer is a replenishment light black toner (LK) having a lightness L * in a powder state of 20 <L * ≦ 55 or a replenishment dark black toner (DK) having 0 ≦ L * ≦ 20. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply black toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light black toner _(LK) (I LK) and the transfer index of the replenishment developer containing the deep black toner replenishment _(DK) (I DK) satisfies the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LK ) <25.0
0.5 <(I _DK ) ≦ 25.0
(I _LK ) <(I _DK )

(11) The image forming method as described in (9) or (10) above, wherein (I _LK ) and (I _DK ) satisfy the following formula.
0 <(I _DK ) − (I _LK ) ≦ 10.0

(12) Carrier / toner mass ratio (C / T (LK)), dark black toner (DK) and replenishment containing the carrier of the light black toner (LK) and replenishment developer containing the carrier (9) to (11), wherein the carrier / toner mass ratio (C / T (DK)) of the developer for toner is (C / T (LK)) <(C / T (DK)) The image forming method according to any one of the above.

(13) The value of a * in the powder state of the light black toner (LK) and the dark black toner (DK) is 0 ≦ a * ≦ 5, and the value of b * is 0 ≦ b * ≦ 5. The image forming method according to any one of (9) to (12).

(14) The carrier is a carrier formed by coating the surface of a carrier core with a coating material, and the coating material contains a coating resin and resin fine particles. The image forming method according to any one of the above.

(15) The transfer material has a toner receiving layer on a surface layer, and the fixing device heats and pressurizes the transfer material on which the toner image is transferred;
A second image heating device that further heats and pressurizes the transfer material that has passed through the first image heating device;
The second image heating apparatus has an endless belt to which the image surface of the transfer material is in close contact, and forcibly cools the transfer material that remains in close contact with the endless belt after heating and pressurization before separation. The image forming method according to any one of (1) to (14).

In the image forming method of the present invention, in an electrophotographic image forming apparatus that continuously outputs high-quality images such as photographs at a high speed, it is possible to improve the mixing property of the replenishment developer and the two-component developer. Therefore, it is possible to make the charging property of the toner uniform and prevent color fluctuations caused by variations in the charge distribution over a long period of time.
In the image forming method of the present invention, it is possible to most effectively exert the long life of the two-component developer, which is an effect of the auto-refresh development method, and it is possible to suppress the consumption of the replenishment developer.
Further, in the image forming method of the present invention, the toner particles are uniformly arranged by charging the toner uniformly, and a high-quality image with uniform gloss such as a silver salt photograph is obtained without collapsing characters and fine lines. Can be output.

In the present invention, the lightness L ^* indicates a value obtained as a toner in a powder state. In general, the lightness L ^* indicates the degree of brightness of a color that can be compared regardless of hue and saturation in the range of 0 to 100 in the L ^* a ^* b ^* color system. In the present invention, L ^* in the toner in the powder state is measured using a spectroscopic color difference meter “SE-2000” (manufactured by Nippon Denshoku Industries Co., Ltd.).

  In the present invention, cyan and magenta toners of 45 <L * ≦ 75, and black toners of 20 <L * ≦ 55 (hereinafter sometimes referred to as “L toners”) are compared to normal toners. The tinting strength is suppressed and the brightness is increased. The reason why the image in the highlight portion is good when toner having high brightness is used is as follows.

  First, a problem when developing a highlight portion using toner having low brightness will be described. When an image in a highlight portion is formed with toner having low lightness (dark color), a low lightness portion developed with toner has a locally high density, and a clear contrast can be formed with a portion not developed with toner. In this case, in the highlight portion, there are naturally many portions that are not developed with toner, and an image is formed in which high density points with low brightness are scattered. This results in an image with a very noticeable graininess.

  On the other hand, in the present invention, the highlight portion is developed using toner having high brightness. When toner with high brightness is used, development is performed using a larger amount of toner than when toner with low brightness is used, so that a highlight image is formed by a large number of toners, that is, image points (color points). It is possible to form a highlight portion having a small difference in brightness between paper and toner and good in terms of graininess (small graininess).

  In the present invention, the lightness of the toner is defined not by the spectral sensitivity characteristic of the image after fixing, but by the spectral sensitivity characteristic in the powder state for the following reason. There are various types of fixing devices and recording members. Depending on the conditions and combinations thereof, the gloss and color gamut that appear even when the same toner is fixed vary greatly. Also, depending on the pressure of the fixing device, the way the toner is crushed differs, which affects the graininess (roughness). In that respect, when the direct colorimetry method according to the present invention is employed, the brightness of the toner itself can be accurately defined because it is not affected by the structure of the fixing device or the transferred material.

  For example, dark solid toner (hereinafter sometimes referred to as “D toner”) is used for the solid portion of the formed image, and the light color toner (L toner) of the present invention is used for the highlight portion. A more preferable effect can be obtained by using different toners depending on the image density to form an image. It is also a preferred embodiment to use a suitable combination of dark color toner (D toner) and light color toner (L toner) according to the density gradation of the image to be formed. The same effect can be obtained by using toners of any hue of magenta (DM toner, LM toner), cyan (DC toner, LC toner) and black (DK toner, LK toner).

  On the other hand, as an image forming method satisfying high image quality and high speed, a two-component developing method using a two-component developer in which toner is mixed with a carrier is adopted in the present invention. The color of the first and last output images varies. This is because the two-component developer is deteriorated due to heavy carrier consumption, resulting in variations in toner charge distribution and fogging. Therefore, in the present invention, development is performed while supplying a replenishment developer containing toner and a carrier to the developing device, the deteriorated carrier in the developing device is sequentially collected, and a fresh carrier of the replenishment developer is sequentially replenished. Auto refresh development method is adopted. The auto-refresh development method can achieve a long life of the two-component developer.

  Although the carrier deterioration has been improved by the auto-refresh development method, and the variation in the toner charge distribution and the occurrence of fogging have been slightly suppressed, the durability of the two-component developer is not yet satisfactory, and the two-component is not satisfactory. Further studies were necessary on the mixing property of the developer and the replenishment developer and the discharge property of the deteriorated carrier.

  Therefore, the inventors analyzed the movement of the replenishment developer from when the replenishment developer was replenished until it passed through the developing device and developed. In addition, a correlation between the ease of movement of the replenishment developer in the developing unit and the variation in the charge distribution was found, and an index representing the ease of movement of the replenishment developer in the developer was found.

  The transportability index of the present invention is a measurement of the moving speed of a sample when a specific physical force is applied. The replenishment developer transportability index and the replenishment developer for replenishment are developed by the developer. It was found that there is a very high correlation with the “speed to reach the developer carrying member (developing sleeve) through the inside”.

The transportability index of the replenishment developer used in the present invention is 0.5 ≦ (I _LC , I _LM , I _LK ) <25.0, 0.5 <(I _DC , I _DM , I _DK ) ≦ 25 .0.
When the transportability index exceeds 25.0, the replenishment developer is 2 in the auto-refresh development method.
Since it moves at a high speed in the developing device before being mixed with the component developer, the frequency of discharging even undegraded carriers is increased. For this reason, the effect of improving the durability of the two-component developer, which is the aim of the auto-refresh development method, is reduced, and the consumption of the replenishment developer is increased.

If it is less than 0.5, it becomes difficult for the replenishment developer to be conveyed in the developing device, and the mixing property of the replenishment developer and the two-component developer is deteriorated particularly in a high-speed image forming apparatus. If the mixing property is deteriorated, the toner and carrier concentrations in the two-component developer become non-uniform, so that density unevenness and color variation frequently occur in the image.

In the present invention, cyan, magenta, and black replenishment developers are specified. However, when full color output is performed, the transportability index of yellow (DY) replenishment developer is 0.5 <I _DY ≦ 25. 0 is preferred.

Further, the transportability index of the replenishment developer used in the present invention is 0.5 ≦ (I _LC , I _LM , I _LK ) <25.0, 0.5 <(I _DC , I _DM , I _DK ) ≦ With 25.0, even if a fixing device that imparts uniform glossiness such as a silver salt photograph used in the present invention is used, it is possible to output a high-quality image in which characters and fine lines are not crushed. This is because, when the transportability index is in the above range, the charging is very stable, so that the toner image transferred to the transfer material is reproduced faithfully to the electrostatic charge image. For this reason, even if pressure is applied by the fixing device, the collapse of characters and fine line portions becomes very inconspicuous.

Although the details of the transportability index will be described later, the transportability index in the present invention is different from an index representing simple fluidity. In the present invention, the replenishment developer is a mixture of toner and carrier, and even if the same toner and carrier are used, the transportability index changes if the mixing ratio of the toner and carrier changes. Further, since the transportability index varies depending on the shape, particle size, and bulk density of the toner and carrier, the transportability index of the replenishment developer can be controlled by the combination of the toner and the carrier.
For example, when the carrier is the same, the transportability index increases as the particle size of the toner decreases and the flowability decreases. When the toner is the same, the transportability index increases as the particle diameter of the carrier decreases and the true specific gravity increases.
There have been many methods for measuring the powder characteristics of a single substance such as a toner or a carrier, but there has been no index for expressing the powder characteristics of the entire mixture such as a developer for replenishment.

In addition, the transportability index of the replenishment developer used in the present invention may be (I _LC ) <(I _DC ), (I _LM ) <(I _DM ), (I _LK ) <(I _DK ). is important. The reason is as follows.
When outputting the picture quality, L toner is consumed in a larger amount than cyan toner, magenta and black for one image. Therefore, the amount of replenishment developer using L toner is larger than the amount replenished in the developing device at one time. At this time, the toner and the carrier are easily scattered around the developing unit using the L toner. Further, since the total amount of the two-component developer in the developing device varies greatly, the discharge of the deteriorated carrier becomes unstable. This causes a variation in the charge distribution of the L toner compared to the D toner, and causes image deterioration. Further, when the photographic image quality is continuously output, the deteriorated carrier discharge port tends to be easily clogged in the developing device using L toner.

On the contrary, the amount of D toner to be replenished at one time is smaller than that of the replenishment developer using L toner. However, D toner may be used not only in photographic image quality but also in a normal full color mode that does not use L toner. Since the normal full color mode is generally used more frequently, the total toner consumption results in the D toner being higher. Therefore, the replenishment developer using D toner is replenished more frequently, and the replenishment developer must be efficiently conveyed to the developing sleeve.

  The developing units for developing the L toner and the D toner are preferably the same or similar in the configuration of the developing unit from the viewpoint of imparting the same charge, the ease of designing the main body, and the cost. . Therefore, in order to output photographic image quality at a particularly high speed, it has been necessary to adjust the balance between supply of replenishment developer and discharge of deteriorated carriers. For this purpose, it is necessary to finely adjust the physical properties of the replenishment developer using L toner and D toner.

Therefore, the present inventors replenished the developer for replenishment using L toner with D toner so that the developer is sufficiently agitated and charged in the developing device as compared with D toner, and the discharged property of the deteriorated carrier is stabilized. The problem has been solved by making the transportability index smaller than that of the developer.
When (I _LC ) ≧ (I _DC ), (I _LM ) ≧ (I _DM ), (I _LK ) ≧ (I _DK ), the total amount of the two-component developer in the developing device using L toner is inadequate. Since it becomes stable, the density fluctuation in the highlight portion occurs. In addition, the replenishment developer containing L toner increases the amount of toner discharged together with the carrier, and the amount of consumption of L toner becomes very large.

  The present inventors have also found that the specific gravity difference between the carrier and the toner must be made as small as possible in order to fully exhibit the effect of controlling the transportability.

When the true specific gravity of the carrier exceeds 4.2 g / cm ³ , the mixing property of the replenishment developer and the two-component developer is deteriorated, and even if the transportability index of the replenishment developer is within the above range, the color tone varies. Will occur. Further, the stress applied to the two-component developer is increased, the developer is likely to be deteriorated, and the effect of extending the life is reduced.

On the other hand, if the true specific gravity of the carrier is less than 2.5 g / cm ³ , carrier adhesion to the image occurs due to the influence of the magnetic characteristics of the carrier, and a high-quality image cannot be obtained. Therefore, the true specific gravity of the carrier is 2.5 to 4.2 g / cm ³ .

In particular, regarding carrier adhesion, since L cyan, L magenta and L black are more likely to adhere than D cyan, D magenta and D black, the true specific gravity of the carrier was 2.5 to 4.2 g / cm ^3. Even when the transportability index increases, carrier adhesion tends to deteriorate. Therefore, in order to prevent carrier adhesion, it is essential that the transportability index of the replenishing L toner is less than 25.0. However, in particular for L cyan, L magenta and L black, transportability is prevented in order to prevent carrier adhesion. More preferably, the index is 20.0 or less.

In addition, 0 <(I _DC ) − (I _LC ) ≦ 10.0, 0 <(I _DM ) − (I _LM ) ≦ 10.0, 0 <(I _DK ) − (I _LK ) ≦ 10.0 Preferably there is. (I _DC ) − (I _L
C ), (I _DM )-(I _LM ), and (I _DK )-(I _LK ) are larger than 10, the difference in chargeability between D toner and L toner increases, so that the gradation of the image varies. It becomes easy to do.
In the present invention, more preferable ranges of (I _DC )-(I _LC ), (I _DM )-(I _LM ), and (I _DK )-(I _LK ) are 1 ≦ (I _DC ) − (I _LC ), respectively. ) ≦ 8, 1 ≦ (I _DM ) − (I _LM ) ≦ 8, 1 ≦ (I _DK ) − (I _LK ) ≦ 8, and particularly preferable ranges are 2 ≦ (I _DC ) − (I _LC ) ≦ 6, 2 ≦ (I _DM ) − (I _LM ) ≦ 6, 2 ≦ (I _DK ) − (I _LK ) ≦ 6.

  The method for adjusting the transportability index of the replenishment developer is not particularly limited as to which method is used in the present invention, but a preferred embodiment is shown in the present invention.

  The weight average particle diameter of the toner is preferably 4.0 to 10.0 [mu] m, and particularly preferably 5.0 to 9.0 [mu] m. If it is smaller than 4.0 μm, fog is likely to occur in the image. On the other hand, if it exceeds 10.0 μm, it becomes difficult to obtain a high-definition image.

  The cohesion degree indicating the fluidity of the toner is preferably 5 to 90, and particularly preferably 15 to 80. If the degree of aggregation is less than 5, toner may be scattered from the developing device. On the other hand, if it exceeds 90, the developability deteriorates and the image may be lowered.

  The carrier (C) and toner (T) in the replenishment developer have 2 toners per 1 part by mass of the carrier (C / T mass ratio = 1/2, carrier concentration: 33.33% (= 1/3 ×). 100)) to 50 parts by mass (C / T mass ratio = 1/50, carrier concentration: 1.96% (= 1/51 × 100)), but particularly preferable to 1 part by mass of the carrier The toner is 5 (carrier concentration: 16.67%) to 30 (carrier concentration: 3.2%) parts by mass (C / T mass ratio refers to the mass of C per unit T (mass)). If the toner is less than 2 parts by mass, the life of the two-component developer is improved, but since the amount of carrier is large, the amount of replenisher becomes heavy and the supply ability from the replenisher container to the developing device deteriorates. . Moreover, since the amount of discharged deteriorated carriers is increased, it is not preferable because the deteriorated carrier recovery means becomes complicated. Furthermore, the actual toner amount in the replenisher container decreases, the replacement frequency of the replenisher container increases, and not only the load on the user increases but also the cost increases, which is not preferable. On the other hand, when the amount exceeds 50 parts by mass, the toner and the carrier are not uniformly dispersed in the replenisher container, and the image quality may become unstable. Further, it is not preferable because the two-component developer needs to be replaced before the end of the life of the image forming apparatus that outputs an electrophotographic image.

In the present invention, since (I _LC ) <(I _DC ), (I _LM ) <(I _DM ) and (I _LK ) <(I _DK ), the developer for replenishing D toner and the replenishing for L toner are used. The physical properties of the toner and carrier may be changed depending on the developer for use, but the C / T mass ratio is (C / T (LC)) <(C
/ T (DC)), (C / T (LM)) <(C / T (DM)) and (C / T (LK)) <(C / T (DK)) It is most preferable to adjust. This is very easy to adjust because the transportability index can be changed without changing the properties of the toner or carrier. In addition, since the amount of deteriorated carrier discharged from the developer for L toner is suppressed, packing and the like are less likely to occur, and a very stable image quality can be output even if an image is output at high speed. is there. In the present invention, a particularly preferable difference in C / T mass ratio is 2% ≦ (C
/ T (DC))-(C / T (LC)) ≦ 10%, 2% ≦ (I _DM ) − (I _LM ) ≦ 10% and 2% ≦ (C / T (DK)) − (C / T (LK)) ≦ 10%.

These configurations in the present invention are very effective when the developing devices for developing the L toner and the D toner have the same or similar configurations.
In the present invention, there are D toner and carrier used in the two-component developer, and D toner and carrier used in the replenishment developer. At this time, the D toner contained in the two-component developer or the replenishment developer may be the same, or different if the transportability index of the replenishment developer satisfies the above range. There may be. Similarly for the carrier, the carrier used in the two-component developer and the carrier used in the replenishment developer may be the same, or the transportability index of the replenishment developer satisfies the above range. If it is, it may be different.
This also applies to the relationship between the L toner and the carrier contained in the two-component developer for L toner and the replenishment developer.
The carriers contained in the two-component developer for D toner and L toner may be the same or different. The carrier contained in the developer for replenishment for D toner and L toner may be the same, or may be different as long as the carrier satisfies the range of the transportability index.
Furthermore, it is possible to use different carriers for each color.

Next, constituent components of the toner used in the present invention will be described.
The toner used in the present invention contains at least a binder resin and a colorant.
As the binder resin contained in the toner used in the present invention, those commonly used for toner are used, and vinyl copolymers represented by styrene- (meth) acrylic copolymers, polyester resins, vinyls. Various resins such as a hybrid resin in which a system copolymer unit and a polyester unit are chemically bonded, an epoxy resin, and a styrene-butadiene copolymer can be used.

  When a polyester resin or a hybrid resin having a polyester unit is used as the binder resin contained in the toner used in the present invention, a polyhydric alcohol is used as a polyester monomer for forming the polyester unit of the polyester resin or the hybrid resin. And polyvalent carboxylic acid, polyvalent carboxylic acid anhydride, or polyvalent carboxylic acid ester can be used as raw material monomers. Specifically, for example, as the dihydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2 -Bisphenol A alkylene oxide adducts such as bis (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1 , 2-Propylene glycol, 1,3-propylene glycol, 1,4-butanediol Neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A And hydrogenated bisphenol A.

  Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Can be mentioned.

  Examples of the divalent carboxylic acid component include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, dodecenyl succinic acid, adipic acid, sebacic acid and azelaic acid, or anhydrous And succinic acid substituted with an alkyl group having 6 to 12 carbon atoms or an anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, and citraconic acid, or anhydrides thereof.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (also known as trimellitic acid), 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, Examples include 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof.

Among the above, in particular, a bisphenol derivative represented by the following general formula (1) as a diol component and a carboxylic acid component (for example, a divalent or higher carboxylic acid or an acid anhydride thereof, or a lower alkyl ester thereof) , Fumaric acid, maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) as the acid component, and polyester resins obtained by condensation polymerization of these are particularly preferred. The polyester resin having this composition has good charging characteristics.

  When the binder resin contained in the toner used in the present invention is a vinyl copolymer or a hybrid resin having a vinyl copolymer unit, the vinyl copolymer or the vinyl copolymer unit of the hybrid resin is used. The following can be used as a vinyl-type monomer for producing | generating this. Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chloro styrene, 3, Styrene derivatives such as 4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene; unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; C, such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride Vinyl halides; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacryl Α-methylene aliphatic monocarboxylic acid esters such as dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, acrylic acid Propyl, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, Acrylic esters such as phenyl laurate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N- N-vinyl compounds such as vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

Further, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Unsaturated dibasic acid half esters such as alkenyl succinic acid methyl half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester; dimethyl maleic acid, dimethyl fumaric acid and the like; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group, such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof. Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  When a hybrid resin having a vinyl copolymer or a vinyl copolymer unit is used as the binder resin to be included in the toner used in the present invention, these resins are crosslinking agents having two or more vinyl groups. It may be cross-linked. The following are mentioned as a crosslinking agent used in this case. Examples of aromatic divinyl compounds include divinylbenzene and divinylnaphthalene; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,4-butanediol di Examples include acrylate, 1,5-pentanediol diacrylate, 1,6 hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylate; linked by alkyl chains containing ether linkages. Examples of the diacrylate compounds include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene glycol # 400 diacrylate. Acrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate and acrylates of the above compounds in place of methacrylate; diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, Polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate and acrylates of the above compounds The thing replaced with a methacrylate is mentioned. Other polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; Examples include allyl cyanurate and triallyl trimellitate.

Examples of radical polymerization initiators used for producing a vinyl resin or a hybrid resin having a vinyl copolymer unit include 2,2′-azobisisobutyronitrile and 2,2′-azobis. (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (-2,4-dimethylvaleronitrile), 2,2′-azobis (-2methylbutyronitrile), dimethyl-2, 2'-azobisisobutyrate, 1,1'-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2'-azobis (2,4,4-trimethylpentane) 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2′-azobis (2-methyl-propane), methyl ethyl ketone peroxide , Ketone peroxides such as acetylacetone peroxide and cyclohexanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetra Methyl butyl hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, di-cumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide Oxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2 Ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, Acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneodecanoate, t-butylperoxy 2-ethylhexanoate, t-butylperoxylaur Rate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy-2-ethyl Sanoeito, di -t- butyl peroxy hexahydro terephthalate, di -t- butyl peroxy azelate and the like.

As the colorant contained in the toner used in the present invention, pigments and / or dyes can be used.
Examples of the color pigment for cyan toner include C.I. I. Pigment blue 2, 3, 15: 3, 15: 4, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45, and a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on a phthalocyanine skeleton having a structure represented by the following formula.

As a coloring pigment for magenta toner, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90 , 112, 114 , 122, 123 , 163, 202 , 206, 207 , 209, 238 , C.I. I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned.

  Examples of the magenta toner dye include C.I. I solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; I. Disper thread 9; I. Solvent violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. B. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; I. Basic dyes such as basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28 may be mentioned.

    As the colorant, the above-mentioned pigment may be used alone, but it is more preferable from the viewpoint of the image quality of a full-color image to improve the sharpness by using a dye and a pigment together.

  In the case of outputting a full color image, the color pigment for yellow toner includes C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; I. Bat yellow 1, 3, 20, etc. are mentioned.

  Examples of the coloring dye for yellow toner include C.I. I. Solvent Yellow 162 and the like, and it is also preferable to use a pigment and a dye together.

  As the colorant for black toner, carbon black; magnetic material; a color adjusted to black using yellow, magenta, and cyan colorants is used.

Examples of the magnetic material include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. Among them, those containing iron oxide as a main component such as triiron tetroxide and γ-iron oxide are preferable. Further, from the viewpoint of controlling the chargeability of the toner, other metal elements such as silicon element and aluminum element may be contained. The magnetic material preferably has a BET specific surface area of ² to 30 m ² / g, particularly 3 to 28 m ² / g, and further preferably has a Mohs hardness of 5 to 7 by a nitrogen adsorption method.

When the L toner is prepared, the content of the colorant in the present invention is preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the binder resin. In addition, when the D toner is prepared, the content of the colorant is preferably 2.5 to 15.0 parts by mass with respect to 100 parts by mass of the binder resin. When using a magnetic material as a colorant for black toner, unlike other colorants, 50 to 200 parts by mass for D toner and 1 to 50 parts by mass for L toner are added to 100 parts by mass of binder resin. Are preferably used.
Especially for black D toner and L toner, the value of a * in the powder state is 0 ≦ a * ≦ 5, b *.
Is preferably 0 ≦ b * ≦ 5. When a * and b * of both the D toner and the L toner or one of them exceeds 5, the difference in the hue of the halftone portion is easily noticeable.

The toner used in the present invention may contain a wax.
Although it does not specifically limit as said wax, For example, the following are mentioned. Oxides of aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight olefin copolymer wax, microcrystalline wax, Fischer-Tropsch wax, paraffin wax, and oxidized hydrocarbon wax Or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax and montanic acid ester wax; esters that are a synthetic reaction product of higher fatty acids such as behenyl behenate and behenyl stearate and higher alcohols Examples thereof include waxes and fatty acid esters such as deoxidized carnauba wax that are partially or fully deoxidized.

In addition, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, and seryl alcohol , Saturated alcohols such as melyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis laurin Saturated fatty acid bisamides such as acid amide and hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N'dioleyl adipic acid amide, N, N 'geo Unsaturated fatty acid amides such as irsebacic acid amide; Aromatic bisamides such as m-xylene bis-stearic acid amide and N, N ′ distearyl isophthalic acid amide; Calcium stearate, calcium laurate, zinc stearate, magnesium stearate, etc. Aliphatic metal salts (generally referred to as metal soaps); waxes grafted with aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; fatty acids such as behenic acid monoglycerides and many others Examples include partially esterified products of monohydric alcohols; methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and the like.

  In the endothermic curve in the differential scanning calorimetry (DSC) of the wax in order to achieve excellent low-temperature fixability, high coloring power, clear color and color mixing, and excellent environmental stability and durability, The peak temperature of the maximum endothermic peak is preferably in the range of 60 to 105 ° C, and more preferably in the range of 70 to 90 ° C. When the temperature is lower than 60 ° C., for example, the storage stability of the toner may be inferior, and when the temperature exceeds 105 ° C., it may be difficult to perform low-temperature fixing desired from the viewpoint of energy saving.

  The wax is used in an amount of 1 to 20 parts by mass, preferably 2 to 15 parts by mass, per 100 parts by mass of the binder resin. If the amount is less than 1 part by mass, there is no effect on the low-temperature fixability, and if it exceeds 20 parts by mass, there may be a problem in storage stability and developability of the toner.

  The toner used in the present invention may contain a charge control agent. As the charge control agent, known ones can be used, and in particular, a charge control agent that has a high charging speed and can stably maintain a constant charge amount is preferable. Specific compounds include negative charge control agents, aromatic carboxylic acids such as salicylic acid, naphthoic acid or dicarboxylic acid, aromatic carboxylic acid derivatives or their metal compounds; sulfonic acid or carboxylic acid groups in the side chain Examples thereof include a polymer compound having boron, a boron compound, a urea compound, a silicon compound, and calixarene. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound or an imidazole compound.

Among the above, the charge control agent that is particularly preferably used is an aromatic carboxylic acid derivative selected from aromatic oxycarboxylic acid and aromatic alkoxycarboxylic acid, and a metal compound of the aromatic carboxylic acid derivative. It is preferable that it is more than the value. The metal compound of the aromatic carboxylic acid is prepared by, for example, dropping an aqueous solution in which a divalent or higher valent metal ion is dissolved into an aqueous sodium hydroxide solution in which the aromatic carboxylic acid is dissolved, heating and stirring, and then adjusting the pH of the aqueous solution. Although it can synthesize | combine by adjusting and cooling to normal temperature and washing with filtered water, it is not limited only to said synthesis | combining method. Examples of the divalent metal include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Pb ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ^{2+, and} Cu ²⁺ . Of these, Zn ²⁺ , Ca ²⁺ , Mg ²⁺ or Sr ²⁺ are preferred. Examples of the trivalent or higher metal include Al ³⁺ , Cr ³⁺ , Fe ³⁺ , Ni ^{3+, and} Zr ⁴⁺ . Among these trivalent or higher metals, Al ³⁺ , Cr ³⁺ or Zr ⁴⁺ is preferable, and Al ³⁺ or Zr ⁴⁺ is particularly preferable. The aromatic carboxylic acid derivative is preferably a salicylic acid derivative. The charge control agent is preferably used in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. If the content falls within this range, the charge level of the toner can be adjusted appropriately, so that the charge amount necessary for development can be easily obtained. Further, during kneading, which is a part of the toner manufacturing process, a metal cross-linking reaction between the carboxyl group present in the binder resin and the central metal of the metal compound of the aromatic carboxylic acid described above is caused appropriately, and the viscoelasticity of the toner It is also possible to adjust the heat melting characteristics of the toner. In addition, the charge control agent concentration on the surface of the toner particles is made higher than that in the toner, and a charge control agent having a higher charging property than the charge control agent existing in the toner is present on the toner particle surface, thereby improving the charging characteristics. It becomes easy to control and is preferable.

It is preferable that a fluidity improver is externally added (hereinafter referred to as external addition) to the toner used in the present invention. Here, the fluidity improver has a function of increasing fluidity by being externally added to the toner particles, and is added from the viewpoint of improving the image quality. For example, fluorine resin powder such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; silica fine powder such as silica fine powder by wet process, silica fine powder by dry process, silica fine powder such as silane compound, titanium cup A treated silica fine powder subjected to a surface treatment with a treating agent such as a ring agent or silicone oil; a titanium oxide fine powder; an alumina fine powder, a treated titanium oxide fine powder, or a treated alumina oxide fine powder is used. Such a fluidity improver gives a good result when the specific surface area by nitrogen adsorption measured by the BET method is 30 m ² / g or more, preferably 50 m ² / g or more. The fluidity improver is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles.

  The toner used in the present invention preferably has a weight average particle diameter of 4.0 to 10.0 μm. By reducing the weight average particle size of the toner in this way, the reproducibility in developing the contour portion of an image, particularly a character image or a line pattern is improved. When the weight average particle size is less than 4.0 μm, for example, the adhesion force to the surface of the photosensitive drum is increased, which tends to cause uneven image unevenness due to transfer defects. Further, the charge amount per unit mass of the toner becomes high, and the image density may be lowered in a low temperature and low humidity environment, for example. Furthermore, due to a decrease in fluidity and an increase in adhesion to a member, for example, frictional charging with a carrier is difficult to be performed smoothly, toner that cannot be sufficiently charged increases, and fogging of non-image areas becomes conspicuous. . In addition, when the weight average particle size exceeds 10.0 μm, since there are few fine particles that can contribute to high image quality, there is a merit that the fluidity of the toner is excellent, but on the fine electrostatic charge image on the photosensitive drum. In some cases, it is difficult to adhere faithfully, the reproducibility of the highlight portion is lowered, and the gradation is also lowered. In addition, fusion to a member such as the surface of the photosensitive drum is likely to occur. Further, when the content of the toner having a particle size of 4.0 μm or less is 3 to 40% by number and the content of the toner having a particle size of 10.0 μm or more is 10% by volume or less, the developability and transfer It is particularly preferable because a toner having a good balance of properties can be easily obtained.

The carrier used for the replenishment developer and the two-component developer will be described.
As described above, the carrier used in the present invention may have a true specific gravity of 2.5 to 4.2 g / cm ³ , and there are no particular restrictions on the type and manufacturing method.

  Examples of the carrier include surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, or rare earth acidic metals, alloys thereof or oxides thereof and ferrite, or binder resins, Examples thereof include a magnetic fine particle dispersed resin carrier composed of a nonmagnetic metal oxide and a magnetic metal oxide.

The carrier is preferably coated with a resin or a coupling agent in order to provide charging stability and environmental stability.
As the carrier, a light metal-containing ferrite carrier having a light metal-containing ferrite as a core and a magnetic fine particle-dispersed resin carrier having a magnetic fine particle-dispersed resin carrier core are preferably used for the following reasons. Ferrite particles that do not contain light metals composed of Cu-Zn, Ni-Zn, and the like used in conventional development methods have a true specific gravity of about 4.9. Must be 4.2 or less.
The light metal-containing ferrite carrier and the magnetic fine particle-dispersed resin carrier can reduce the true specific gravity as compared with a ferrite carrier containing heavy metal, and can be preferably used as the carrier of the present invention. Among them, particularly preferred in the present invention is a polymerized magnetic fine particle dispersed resin carrier containing a nonmagnetic metal oxide and magnetite and produced by a polymerization method. Polymerized magnetic fine particle dispersed resin carrier containing non-magnetic metal oxide and magnetite can control the magnetic properties and specific gravity relatively easily, and can achieve a sharp particle size distribution with little shape distortion. It is relatively easy to make a sphere with high particle strength, has excellent fluidity and transportability during replenishment, and has an effect of making the toner charge distribution very uniform. Therefore, it is difficult for the carrier developer to segregate in the replenishment developer, and it is preferable for improving the discharge property from the replenishment developer container. In particular, the polymerized magnetic fine particle-dispersed resin carrier has a smaller porosity than its shape and particle size distribution, so that the capacity of the replenishment developer storage container can be reduced and the image forming apparatus can be easily downsized. In addition, since the particle size and resistance can be controlled over a wide range, it is particularly preferable because it is suitable for a high-speed copying machine, a high-speed laser beam printer, or the like in which the developing sleeve or the number of magnets in the sleeve is large.

Next, the magnetic fine particle dispersed resin carrier most preferably used in the present invention will be described.
As the metal compound particles used for the carrier, the above-described metal compound particles having magnetism and the following non-magnetic metal compound particles may be mixed and used.

Nonmagnetic metal compound particles include, for example, Al ₂ O ₃ , SiO ₂ , CaO, TiO ₂ , V ₂ O ₅ , CrO, MnO ₂ , α-Fe ₂ O ₃ , CoO, NiO, CuO, SnO, ZnO. , S
Examples include rO, Y ₂ O ₃ and ZrO ₂ . In this case, one kind of metal compound particles can be used, but it is particularly preferable to use a mixture of at least two kinds of metal compound particles. As the metal compound particles, it is more preferable to use particles having similar specific gravity and shape in order to increase the adhesion to the binder resin and the strength of the carrier core particles.

Preferred specific examples of the combination include magnetite and hematite, magnetite and γ-Fe ₂ O ₃ , magnetite and SiO ₂ , magnetite and Al ₂ O ₃ , magnetite and TiO ₂ , magnetite and Ca—Mn—Fe ferrite, magnetite and Examples thereof include Ca—MgFe ferrite. Of these, a combination of magnetite and hematite is particularly preferred.

The content of the metal compound particles is preferably 80 to 95% by mass with respect to the magnetic fine particle dispersed resin carrier core.
When the content of the metal compound particles is less than 80% by mass, the chargeability tends to become unstable, and the residual charge of the carrier tends to remain particularly in a low temperature and low humidity environment. It becomes easy to adhere to the surface of the fine particle dispersed resin carrier particles. When the content of the metal compound particles exceeds 95% by mass, the strength of the magnetic fine particle dispersed resin carrier is lowered, and problems such as cracking of the magnetic fine particle dispersed resin carrier due to durable use are likely to occur. Furthermore, it becomes difficult to obtain a carrier having a true specific gravity within the range defined by the present invention.

  The binder resin used for the magnetic fine particle-dispersed resin carrier core particles is a thermosetting resin and is preferably a resin that is partly or wholly crosslinked three-dimensionally. As a result, the dispersed metal compound particles can be firmly bound, so that the strength of the magnetic fine particle-dispersed resin carrier core can be increased, and the detachment of the metal compound particles hardly occurs even in a large number of copies. The coating resin can be coated better.

  The method for obtaining the carrier core particles is not particularly limited to the method described below, but in the present invention, in a solution in which the monomer, metal oxide and solvent are uniformly dispersed or dissolved. Therefore, a production method by a polymerization method in which particles are produced by polymerizing monomers is preferably used. In particular, a method of obtaining a magnetic material-dispersed resin carrier core having a sharp particle size distribution and a small amount of fine powder by subjecting a metal oxide to a lipophilic treatment is suitably used.

  In the present invention, in the case of a magnetic fine particle dispersed resin carrier used in combination with a small particle size toner having a weight average particle size of 4.0 to 10.0 μm in order to achieve high image quality, the carrier particle size is also the same as that of the toner. It is preferable to reduce the particle size according to the particle size, and the above-described manufacturing method is particularly preferable because a carrier with less fine powder can be manufactured regardless of the average particle size even if the carrier particle size is reduced.

As the monomer used to form the binder resin for the carrier core particles, a radical polymerizable monomer can be used. For example, styrene; styrene derivatives such as o-methyl styrene, m-methyl styrene, p-methoxy styrene, p-ethyl styrene, p-tertiary butyl styrene; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate Acrylates such as n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; methacrylic acid, methyl methacrylate , Ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, meta Methacrylic acid esters such as phenyl laurate, dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate, benzyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide; methyl vinyl ether, ethyl vinyl ether , Propyl vinyl ether, n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether And vinyl ethers; and diene compounds such as butadiene.
These monomers can be used alone or in combination, and a suitable polymer composition can be selected so that preferable characteristics can be obtained.

Other monomers include bisphenols and epichlorohydrin as starting materials for epoxy resins; phenols and aldehydes of phenol resins; ureas and aldehydes of urea resins; melamines and aldehydes of melamine resins.
The most preferred binder resin is a phenolic resin. Examples of the starting material include phenol compounds such as phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcil, and p-tert-butylphenol, and aldehyde compounds such as formalin, paraformaldehyde, and furfural. A combination of phenol and formalin is particularly preferable.

  When these phenol resins or melamine resins are used, a basic catalyst can be used as a curing catalyst. As the basic catalyst, various catalysts used in the production of ordinary resole resins can be used. Specific examples include amines such as aqueous ammonia, hexamethylenetetramine, diethyltriamine, and polyethyleneimine.

  In the present invention, the metal compound particles contained in the carrier core are preferably oleophilic in order to sharpen the particle size distribution of the carrier particles and to prevent the metal compound particles from being detached from the carrier. . When forming carrier core particles in which metal compound particles having been subjected to lipophilic treatment are dispersed, particles insolubilized in the solution are formed at the same time as the polymerization reaction proceeds in a liquid in which the monomer and solvent are uniformly dispersed or dissolved. . The oleophilic treatment is considered to have an effect of taking the metal oxide into the particles uniformly and at a high density during particle generation and an effect of preventing aggregation of the particles and sharpening the particle size distribution.

The lipophilic treatment is one or two selected from an epoxy group, an amino group and a mercapto group
It is preferable to treat with an organic compound having a functional group of more than one species or a lipophilic treatment agent that is a mixture thereof. In particular, an epoxy group is preferably used in order to obtain a carrier having a stable charge imparting ability.

The metal oxide particles are preferably treated with a lipophilic agent of 0.1 to 10 parts by weight, more preferably 0.2 to 6 parts by weight per 100 parts by weight of the metal compound particles. It is preferable for enhancing lipophilicity and hydrophobicity.
The oleophilic treatment can be carried out by either a continuous method or a badge method, but usually a batch method is adopted.

  The carrier used in the present invention is preferably coated with a resin or a coupling agent in order to provide charging stability and environmental stability.

  The carrier is preferably in a form in which a resin is coated on the surface of the carrier core (that is, a form having a resin coating layer), but the resin is not particularly limited as long as it can be used as a matrix resin. It can be appropriately selected depending on, for example, polyolefin resins such as polyethylene and polypropylene; polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone. Polyvinyl resins and polyvinylidene resins such as: vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or a modified product thereof; Fluorocarbon resins such as rafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene; silicone resins; polyesters; polyurethanes; polycarbonates; phenol resins; urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamides Examples thereof include amino resins such as resins; and known resins such as epoxy resins. These may be used individually by 1 type and may use 2 or more types together.

  In the present invention, among these resins, it is preferable to use at least a fluororesin and / or a silicone resin. Use of a fluorine-based resin and / or a silicone resin as the resin is advantageous in that it has a high effect of preventing carrier contamination (impact) due to toner and external additives.

  As the coupling agent, aminosilane is preferably used. As a result, an amino group having positive chargeability can be introduced on the surface of the carrier, and the toner can be favorably imparted with negative charge characteristics. Furthermore, in the case of a magnetic material-dispersed resin carrier, the presence of an amino group activates both the lipophilic agent used in the metal compound and the silicone resin, so that the adhesion between the silicone resin and the carrier core is improved. A stronger coating layer can be formed by further increasing and simultaneously promoting the curing of the resin.

  Resin particles and / or conductive particles can be dispersed in the resin coating layer, but it is particularly preferable to disperse resin particles.

  Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among them, thermosetting resin particles that are relatively easy to increase the hardness are suitable, and in order to impart negative chargeability to the toner, it is preferable to use resin particles containing nitrogen atoms. These resin particles and conductive particles may be used alone or in combination of two or more.

Examples of the conductive particles include metal particles such as gold, silver or copper, carbon black particles, semiconductive oxide particles such as titanium oxide or zinc oxide, or titanium oxide, zinc oxide, barium sulfate, aluminum borate or titanium. Particles whose surfaces such as potassium acid powder are covered with tin oxide, carbon black or metal can be used. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular in the formation method of the said resin coating layer. For example, a method using a resin coating layer forming liquid containing the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin, a fluorine resin, or a silicone resin as a matrix resin in a solvent. Is mentioned. Specifically, the dipping method in which the carrier core is immersed in the resin coating layer forming liquid, the spray method in which the resin coating layer forming liquid is sprayed on the surface of the carrier core, and the resin coating in a state where the carrier core is suspended by flowing air. Examples thereof include a kneader coater method in which the solvent is removed by mixing with a layer forming solution.

  There are various methods for producing the toner used in the present invention. For example, in the case of manufacturing by a pulverization method, a predetermined amount of materials (internal additives) such as a binder resin and a colorant constituting the toner particles are weighed and mixed and mixed (this is a “raw material mixing step”). Called). As an example of a mixing apparatus used when mixing raw materials, there are a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauter mixer, and the like.

  Next, the mixed toner raw materials are melted and kneaded to melt resins, and a colorant or the like is dispersed therein to obtain a colored resin composition (this is referred to as “melting and kneading step”). In this melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to the advantage of being capable of continuous production. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd. In general, a twin-screw extruder manufactured by Kay C.K. or a co-kneader manufactured by Buss is used.

  Further, the colored resin composition obtained by the melt kneading step is melted and kneaded, rolled with two rolls or the like, and cooled through a cooling step of cooling with water cooling or the like.

  Next, the cooled product of the obtained colored resin composition is generally pulverized to a desired particle size in a pulverization step. In the pulverization step, first, coarse pulverization is performed with a crusher, a hammer mill, a feather mill, or the like, and further, pulverization is performed with a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a super rotor manufactured by Nisshin Engineering. After that, if necessary, it is classified using a classifier such as an inertia class elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.) or a centrifugal classifier turboplex (manufactured by Hosokawa Micron Co., Ltd.), and the weight average particle diameter Gives toner particles of 4.0 to 10.0 μm.

  If necessary, surface modification (ie, spheroidization) may be performed in the surface modification step to form toner particles. Examples of such an apparatus for surface modification include a hybridization system manufactured by Nara Machinery Co., Ltd., a mechano-fusion system manufactured by Hosokawa Micron Corporation, and a surfing system manufactured by Nippon Pneumatic Co., Ltd. Further, if necessary, a sieving machine such as a wind-type sieve high voltor (manufactured by Shin Tokyo Machine Co., Ltd.) may be used.

  Also, a method of directly producing toner particles by suspending a polymerizable monomer composition in water and polymerizing the composition, directly using a water-based organic solvent that is soluble in the monomer and insoluble in the obtained polymer. Conventionally known production methods such as a dispersion polymerization method for producing toner particles and a method for producing toner particles by aggregating and associating an emulsion produced by emulsion polymerization with a colorant can also be employed.

  Furthermore, as a method of externally adding the external additive, a predetermined amount of classified toner and various known external additives are mixed, and a high-speed stirrer that applies shear force to the powder such as a Henschel mixer or a super mixer is removed. The toner can be obtained by stirring and mixing as an accessory.

Next, the structure of an example of the surface modification apparatus preferably used in the present invention is shown.
The batch type surface reforming apparatus shown in FIG. 1 includes a cylindrical main body casing 30, a top plate 43 installed on the upper portion of the main body casing so as to be openable and closable; A cooling jacket 31 through which cooling water or antifreeze can be passed; a plurality of square disks 33 on the upper surface, which are attached to the central rotating shaft in the main body casing 30 as surface modification means, in a predetermined direction Dispersion rotor 32, which is a disk-like rotating body that rotates at high speed; liner 34 that is fixedly arranged around dispersion rotor 32 at a constant interval and that has a large number of grooves on the surface facing dispersion rotor 32 A classification rotor 35 for continuously removing fine powder and ultrafine powder having a predetermined particle size or less in the finely pulverized product; cold air inlet 4 for introducing cold air into the main body casing 30; A charging pipe having a raw material charging port 37 and a raw material supplying port 39 formed on the side surface of the main body casing 30 for introducing finely pulverized material (raw material); discharging toner particles after the surface modification treatment to the outside of the main body casing 30; A product discharge pipe having a product discharge port 40 and a product extraction port 42 for opening and closing; an openable and closable raw material installed between the raw material input port 37 and the raw material supply port 39 so that the surface modification time can be freely adjusted A supply valve 38; and a product discharge valve 41 installed between the product discharge port 40 and the product extraction port 42.
The surface of the liner 34 has grooves as shown in FIGS. 6A and 6B, which is preferable for efficiently modifying the surface of the toner particles. As shown in FIGS. 3A and 3B, the number of the rectangular disks 33 is preferably an even number in consideration of the rotational balance. FIGS. 5A and 5B are explanatory diagrams of the rectangular disk 33. FIG.
The classification rotor 35 shown in FIGS. 1, 2 and 7 is preferably rotated in the same direction as the rotation direction of the dispersion rotor 32 in order to increase the efficiency of classification and the efficiency of surface modification of toner particles.
The fine powder discharge pipe has a fine powder discharge port 45 for discharging fine powder and ultrafine powder removed by the classification rotor 35 to the outside of the apparatus.

  The surface modification apparatus further includes a cylindrical guide ring 36 as a guide means having an axis perpendicular to the top plate 43 in the main body casing 30 as shown in FIGS. 4 (A) and 4 (B). Have. The upper end of the guide ring 36 is provided at a predetermined distance from the top plate, and the guide ring is fixed to the main body casing 30 by a support so as to cover at least a part of the classification rotor 35. The lower end of the guide ring 36 is provided at a predetermined distance from the rectangular disk 33 of the dispersion rotor 32. In the surface modification apparatus, a space between the classification rotor 35 and the dispersion rotor 32 is guided into a first space 47 outside the guide ring 36 and a second space 48 inside the guide ring 36. Divided by 36. The first space 47 is a space for guiding the finely pulverized product and the surface-modified particles to the classification rotor 35, and the second space guides the finely pulverized product and the surface-modified particles to the dispersion rotor. It is a space for. A gap between the plurality of rectangular disks 33 installed on the dispersion rotor 32 and the liner 34 is a surface modification zone 49, and the classification rotor 35 and a peripheral portion of the classification rotor 35 are classification zones 50. .

As shown in FIG. 7, the finely pulverized product introduced into the raw material hopper 380 passes through the fixed amount feeder 315, enters the apparatus from the raw material supply port 37 through the raw material supply valve 38 through the raw material supply port 38. Supplied. In the surface reforming apparatus, the cold air generated by the cold air generating means 319 is supplied into the main body casing from the cold air introduction port 46, and the cold water from the cold water generating means 320 is supplied to the cold water jacket 31, Adjust the temperature to a predetermined temperature. The supplied finely pulverized product swirls in the first space 47 outside the cylindrical guide ring 36 by the swirl flow formed by the suction air volume by the blower 364, the rotation of the dispersion rotor 32, and the rotation of the classification rotor 35. However, the classification process is performed by reaching the classification zone 50 in the vicinity of the classification rotor 35. The direction of the swirl flow formed in the main body casing 30 is the same as the rotation direction of the dispersion rotor 32 and the classification rotor 35.

  The fine powder and super fine powder to be removed by the classification rotor 35 are sucked from the slit of the classification rotor 35 (see FIG. 2) by the suction force of the blower 364 and are passed through the fine powder discharge port 45 and the cyclone inlet 359 of the fine powder discharge pipe. 369 and bug 362. The finely pulverized product from which fine powder and ultrafine powder have been removed reaches the surface modification zone 49 in the vicinity of the dispersion rotor 32 via the second space 48, and the square disk 33 (hammer) provided in the dispersion rotor 32 and the main body. The surface modification treatment of the particles is performed by the liner 34 provided in the casing 30. The particles subjected to the surface modification reach the classification rotor 35 again while turning along the guide ring 36, and fine particles and ultrafine particles are removed from the surface-modified particles by the classification rotor 35 classification. . After performing the treatment for a predetermined time, the discharge valve 41 is opened, and the surface-modified toner particles from which fine powder having a predetermined particle diameter or less and ultrafine powder are removed are taken out from the surface reforming apparatus. The toner particles adjusted to a predetermined weight average diameter, adjusted to a predetermined particle size distribution, and further surface-modified to a predetermined circularity are transferred to the external additive adding step by the toner particle transport means 321. .

  The surface reforming apparatus used in the present invention includes a dispersion rotor 32, a finely pulverized product (raw material) input unit 39, a classification rotor 35, and a fine powder discharge unit from the lower side in the vertical direction. Therefore, normally, the drive portion (motor or the like) of the classification rotor 35 is provided further above the classification rotor 35, and the drive portion of the dispersion rotor 32 is provided further below the dispersion rotor 32. The surface reforming apparatus used in the present invention is a classifying rotor for finely pulverized material (raw material) such as a TSP classifier (manufactured by Hosokawa Micron) having only a classifying rotor 35 described in JP-A-2001-259451. It is difficult to supply from the vertically upward direction of 35.

  In the present invention, it is preferable that the tip peripheral speed of the classification rotor 35 having the largest diameter is 30 to 120 m / sec. The tip circumferential speed of the classification rotor is more preferably 50 to 115 m / sec, and further preferably 70 to 110 m / sec. If it is slower than 30 m / sec, the classification yield tends to decrease, and the amount of ultrafine powder tends to increase in the toner particles. If it is faster than 120 m / sec, the problem of increased vibration of the device is likely to occur.

    Furthermore, it is preferable that the tip peripheral speed of the portion with the largest diameter of the dispersion rotor 32 is 20 to 150 m / sec. The tip peripheral speed of the dispersion rotor 32 is more preferably 40 to 140 m / sec, and further preferably 50 to 130 m / sec. When it is slower than 20 m / sec, it is difficult to obtain surface-modified particles having sufficient circularity, which is not preferable. When the speed is higher than 150 m / sec, particles are likely to be fixed inside the apparatus due to the temperature rise inside the apparatus, and the classification yield of the toner particles is likely to be lowered. By setting the tip peripheral speeds of the classification rotor 35 and the dispersion rotor 32 in the above range, the classification yield of the toner particles can be improved and the surface modification of the particles can be performed efficiently.

Next, the transportability index will be described.
The “transportability index” is obtained, for example, by measuring with a parts feeder shown in FIG. 9 (see Konica Minolta, Inc., JP-A-2004-109603). This is an index of the mobility of toner particles in a state where a constant vibration is applied.

In the present invention, the transportability index is used as an index of easiness of movement in the developing device when the replenishment developer is supplied to the developing device.
Specifically, as shown in FIG. 9, the parts feeder A is composed of a drive source C for generating a specific vibration and a cylindrical ball D supported above the drive source C. The ball D is formed with a spiral slope E connecting the bottom surface and the upper end edge along the inner peripheral wall surface.

Here, the slope E is disposed in such a manner that its upper end Ea protrudes radially outward from the side wall of the ball D at the same height position as the upper end edge of the ball D.
In FIG. 9, F is a central axis of the ball D, G is a saucer provided below the upper end Ea of the slope E, and B is a weighing means connected to the saucer G.

  In this parts feeder A, the rotational power supplied by the drive source C is transmitted to the ball D to convert it into a vibrating motion that vibrates the ball D as a whole, and the return position of the vertical motion is arranged at an angle. When the toner is changed by the action of the spring, the toner positioned in the ball D is transferred upward along the slope E and falls onto the tray G from the upper end Ea of the slope E.

  Thus, in the measurement of the toner transportability index according to the present invention, 1 g of toner is introduced around the central axis F inside the ball D, the driving source C is set to a frequency of 135 Hz, and the amplitude of the ball D is 0.26 mm. And the toner is transported upward along the slope E to reach the receiving tray G. When the amount of toner reaching the receiving tray G measured by the measuring means B reaches 300 mg and 700 mg, The time from when the driving of the driving source C is started can be measured and calculated using the following general formula (1).

  In the general formula (1), T300 indicates the time required to transfer 300 mg of toner to the tray G, and T700 indicates the time required to transfer 700 mg of toner to the tray G. In the present invention, the transportability index was set to 0 when 700 mg or more did not fall on the pan G even after 20 minutes from the start of measurement.

  Next, an example of an image forming apparatus using the two-component developing method of the present invention will be described. However, the developing device used in the two-component developing method of the present invention is not limited to this.

FIG. 10 is a schematic configuration diagram of an electrophotographic full-color image forming apparatus equipped with a rotary rotating developing device. As shown in FIG. 10, a color scanner 101 and a color printer 102 are provided. The color scanner 101 has an illumination lamp 104 for illuminating the original 103, and reflected light from the original 103 illuminated by the illumination lamp 104 is a color sensor 107 through mirror groups 105 a, 105 b, 105 c and a lens 106. Imaged on top. The color sensor 107 converts the formed optical image, that is, the color image information of the original 103 into, for example, blue (hereinafter referred to as B), green (hereinafter referred to as G), and red (hereinafter referred to as R) color separation light. Read and convert to electrical image signal. The R, G, B image signals from the color sensor 107 are converted into black (hereinafter referred to as K), cyan (hereinafter referred to as C), magenta by color conversion processing in an image processing unit (not shown). (Hereinafter referred to as M) and yellow (hereinafter referred to as Y) image data.
The color printer 102 has a laser scanner unit 28. The laser scanner unit 28 modulates laser light based on the color image data from the color scanner 101, and scans the laser light with a polygon mirror 28a, so that it is statically placed on the photosensitive member (latent image carrier) 21. An electrostatic latent image is formed. The photosensitive member 21 is rotationally driven in a direction (counterclockwise direction) indicated by an arrow A in the drawing. Around the photoconductor 21, a photoconductor cleaning unit (including a pre-cleaning static eliminator) 212, a charger 27, and a rotary developer 213 are disposed. The rotary developer 213 includes an M developer 13DM and a C developer. 13DC, Y developing unit 13DY, DK developing unit 13DK, and LK developing unit 13LK are held. The rotation developer 213 is controlled to rotate in the direction indicated by the arrow R in the drawing so that the developer of a predetermined color is in contact with the photosensitive member 21. The inside of each developing device includes, for example, a developer carrier, a developing tank in which a two-component developer is stored, a replenishing agent container in which a replenishing agent is stored, and a replenisher from the replenishing agent container to the developing tank. At least a replenisher supplying means for supplying and a developer discharging means for removing a part of the two-component developer in the developing tank when necessary. FIG. 11 is a schematic configuration diagram of the developing devices 13DM, 13DY, 13DC, 13DK, and 13LK in FIG. Referring to FIG. 11, the flow of transport until the two-component developer in the developing device is developed will be described.

  The developing sleeve 6 as a developer carrying member includes a fixed magnet roll 8 and is driven to rotate while maintaining a predetermined developing interval with the peripheral surface of the image carrying member 1. The developing sleeve 6 and the image carrier 1 may be in contact with each other. The regulating member 7 has rigidity and magnetism, and is pressed against the developing sleeve 6 with a predetermined load with no developer interposed therebetween, or is arranged with a predetermined interval between the developing sleeve 6 and the developing member 6. Etc., used in various forms. The pair of developer agitating / conveying members 10 and 11 has a screw structure, conveys and circulates the two-component developer in opposite directions, and sufficiently agitates and mixes the toner and the magnetic carrier to form a two-component developer. It acts to send to the sleeve 6. The magnet roll 8 is formed of, for example, a four-pole magnet having equal magnetic force in which N poles and S poles are alternately arranged at equal intervals, or forms a repulsive magnetic field at a portion in contact with a scraper (not shown). In order to facilitate peeling of the system developer, one pole may be missing to form five poles, and the developer may be included while being fixed in the developing sleeve 6.

The two developer agitating / conveying members 10 and 11 also serve as agitating members that rotate in directions opposite to each other. The developer is transported to the developing sleeve 6 and is made into a homogeneous two-component developer that is triboelectrically charged by the mixing action of the toner and the magnetic carrier. The two-component developer is layered on the peripheral surface of the developing sleeve 6. Adhere to. 2-component developer on the surface of the developing sleeve 6, the regulating member 7 having a double structure comprising a non-magnetic material and a magnetic materials provided to face the magnetic poles of the magnet roll 8 to form a uniform layer. The uniformly formed developer layer develops the electrostatic latent image on the peripheral surface of the image carrier 1 in the development region, and forms a toner image.

  In FIG. 10, the toner image formed on the photoconductor 21 is transferred onto the intermediate transfer belt 22. The intermediate transfer belt 22 is stretched around a first transfer bias roller 217, a driving roller 220 that drives the intermediate transfer belt 22, and driven roller groups 218, 219, and 237. The second transfer bias roller 221 is disposed at a position facing the driven roller 219 of the intermediate transfer belt 22, and the second transfer bias roller 221 is separated from the intermediate transfer belt 22 by a separation / contact mechanism (not shown). It is driven so that it can be detached.

A belt cleaning unit 222 is provided at a predetermined position facing the driven roller 237 on the surface side of the intermediate transfer belt 22. This belt cleaning unit 222 is separated from the belt surface of the intermediate transfer belt 22 by a contact / separation mechanism (not shown) from the start of printing until the belt transfer of the rear end portion of the final color toner image is completed. At this predetermined timing, the belt surface of the intermediate transfer belt 22 is contacted, and the belt surface is cleaned.
The intermediate transfer belt 22 is provided with a reference flag (mark) for adjusting an exposure position, which will be described later. The position of the reference flag is arranged at a position upstream of the photoconductor 21. It is detected by an existing HP (home position) sensor 22a.
To the intermediate transfer belt 22, the toner images formed on the photosensitive member 21 are sequentially superimposed and transferred by the first transfer bias roller 217, and finally the full-color toner images (Y, M, C, DK, LK images are superimposed). The full-color toner image is transferred by the second transfer bias roller 221 to the transfer material fed from the cassette 223 via the paper feed roller 224, the transport roller 226, and the registration roller 225, and the full-color toner image is transferred. The transfer material is hot-pressed in the fixing device 25, and the toner image is fixed to the transfer material.
Thereafter, the image not subjected to the glossing process is discharged out of the apparatus, and the image subjected to the glossing process is conveyed to the fixing device F. The fixing device F will be described later.

  When the copying operation as described above is repeated, the toner in the two-component developer housed in the developing tank 17 in the developing units 13DM, 13DY, 13DC, 13DK and 13LK in FIG. The ratio of the toner to the carrier, that is, the toner concentration is decreased. This change in toner density is detected by a toner density sensor (not shown) provided in the developing tank 17, and feedback control is performed by the replenisher supply means so that the toner density always falls within an appropriate range necessary for development. The toner is supplied from the supply port of the supply device 9 to the developing tank 17 in the developing device. In the present invention, since a carrier is also included in the replenisher, the replenisher is replenished so that the consumed toner amount matches the toner amount in the replenisher to be replenished.

  On the other hand, the carrier in the two-component developer in the developing tank 17 is not consumed by the development, and is stirred together with the toner in the developing tank 17, or the magnetic force of the magnet roll 8 and the image carrier 1. The surface is gradually contaminated and deteriorated due to the influence of contact and the like. As the carrier deteriorates in this way, a predetermined charge amount cannot be applied to the toner, resulting in a reduction in image quality. Therefore, it is necessary to replace the deteriorated carrier which is not consumed in the developing device with a new carrier. In FIG. 10, as a means for replenishing a new carrier into the developing device, a replenisher in which a toner for replenishment and a predetermined amount of carrier are mixed in a replenisher supply device (not shown) is conveyed by a replenisher supplier 9. The developing tanks 13DM, 13DY, 13DC, 13DK and 13LK are replenished from the replenishing port. The excess two-component developer is discharged from the developer discharge means (including the developer discharge port 34, the communication pipe 36, and the developer recovery port 35) on the developing device side as described below.

The replacement of the two-component developer using the rotational movement in the rotating developing device 213 shown in FIG. 10 will be described with reference to FIGS. The replenisher supplied from the replenishing port of the replenisher supplier 9 on the near side in FIG. 11 is agitated with the two-component developer by the developer agitating / conveying member 10, and 10 and 11 at the end opposite to 9 are connected. It is conveyed to the hole. The agitated two-component developer moves toward 11, and is further conveyed to the developing sleeve 6 while being agitated by the developer agitating / conveying member 11, and adhered in a layered manner. The two-component developer on the developing sleeve 6 used for development is from the developer agitating / conveying member 11 to the 10th side from the hole where the replenishing port of the replenishing agent feeder 9 is connected to the front side 10 and 11. Move to the stirring chamber.
When the replenisher container 9 continues to be replenished as described above, the magnetic carrier in the replenisher is not consumed, and the two-component developer in the developing device increases. When the developing device is located at 13DY in the developing device 213 and the surface height of the two-component developer in the developing device exceeds a certain level, excess two-component developer is discharged from 34 to the outside of the developing device. .

In the developing device 213 that employs the rotational movement method of the full-color image forming apparatus, the developing devices 13DM, 13DY, 13DC, 13DK, and 13LK rotate and move inside the developing device 213 and are opposed to the image carrier 1 during development. The image is rotated and moved for development, and when not developed, the image is rotated to a position not facing the image carrier 1.
The two-component developer overflowing from the developer discharge port 34 provided in the developing device 2 at the position where the developing device 13DY is opposed to the photosensitive member 21 and performing the developing operation passes through the communication pipe 36 by the rotating operation. It moves, is discharged from the developer recovery port 35 provided near the rotation center axis of the rotary developing device switching device, and is recovered by the developer recovery device 38.
Specifically, as the two-component development method of the present invention, a magnetic brush developer is used as the developer, and an alternating voltage is applied to the developer carrying member to form an alternating electric field in the development region, It is preferable to perform development while in contact with the photoreceptor 21. The distance between the developer carrying member (developing sleeve) 6 and the photosensitive member 21 (SD distance) is preferably 100 to 1000 μm because it is favorable in preventing magnetic carrier adhesion and improving dot reproducibility. If it is narrower than 100 μm, the supply of the two-component developer tends to be insufficient, and the image density tends to be low. Or the force that restrains the magnetic carrier is weakened, and the magnetic carrier is likely to adhere.

The voltage between the peaks of the alternating electric field formed by applying the developing bias is preferably 300 to 3000 V, and the frequency is 500 to 10000 Hz, preferably 1000 to 7000 Hz, which can be appropriately selected depending on the process. In this case, examples of the waveform of the AC voltage for forming the alternating electric field include a triangular wave, a rectangular wave, a sine wave, or a waveform with a changed duty ratio. In order to cope with the change in the toner image formation speed, development is performed by applying a developing bias having a discontinuous AC voltage (a DC voltage intermittently superimposed with an AC voltage) to the developer carrier. Is preferred. When the applied voltage is lower than 300 V, it is difficult to obtain a sufficient image density, and the fog toner in the non-image area may not be recovered well. On the other hand, when the voltage exceeds 3000 V, the electrostatic latent image is disturbed through the magnetic brush, and the image quality may be deteriorated.
By using a two-component developer having a well-charged toner, the antifogging voltage (Vback) can be lowered, and the primary charge of the image carrier can be lowered. Long life can be achieved. Vback is 200 V or less, more preferably 150 V or less, although it depends on the development system. The contrast potential is preferably 100 to 400 V so that a sufficient image density is obtained.
On the other hand, when the frequency is lower than 500 Hz, although it is related to the process speed, when the toner in contact with the image carrier is returned to the developing sleeve, sufficient vibration is not applied and fogging is likely to occur. If it exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is likely to deteriorate.

A photoconductor used in an image forming apparatus to which the two-component developing method of the present invention is applied will be described. The structure of the image carrier used in the image forming apparatus to which the two-component developing method of the present invention is applied may be the same as that of a photoreceptor used in a normal image forming apparatus. For example, a conductive substrate such as aluminum or SUS. A photosensitive member having a structure in which a conductive layer, an undercoat layer, a charge generation layer, a charge transport layer, and, if necessary, a charge injection layer are provided in this order.
The conductive layer, undercoat layer, charge generation layer, and charge transport layer may be those usually used for a photoreceptor.

  With reference to FIG. 13, another aspect of an image forming method having a developing device to which the two-component developing method of the present invention is applied will be described. FIG. 13 is a schematic diagram of a full-color image forming apparatus. The full-color image forming apparatus in FIG. 13 does not have an independent cleaning unit for collecting and storing the transfer residual toner remaining on the photoreceptor, and the image carrier after the developing unit transfers the toner image onto the transfer material. A developing simultaneous cleaning method for collecting the toner remaining in the toner is performed.

Similarly to the developing device shown in FIG. 11, the developing means of the full-color image forming apparatus shown in FIG. 13 also has a developer carrier, a developing tank, a replenisher supplying means, and a developer discharging means, and the copying operation is repeated. Thus, the toner concentration detecting sensor 85 detects that the toner concentration in the developing tank has decreased, and the replenisher supply means performs feedback control so that the toner concentration falls within an appropriate range necessary for development. A replenisher is supplied from 65a to the developing device 63a. When the replenisher is replenished by the replenisher supplying means, the two-component developer in the developing tank increases in the amount of the magnetic carrier, so that the increased amount overflows and is discharged by the developer discharging means.

  Since the developing device (see FIG. 11) used in the image forming apparatus shown in FIG. 13 is not of the rotational movement type, for example, the discharged two-component developer drops from 34 to the communication pipe 36. The two-component developer that has fallen into the communication pipe 36 is conveyed to the developer recovery port 35 by a conveyance screw (not shown) installed in the communication pipe 36 and is collected by the developer collection unit 38.

  The full-color image forming apparatus main body includes a first image forming unit Pa, a second image forming unit Pb, a third image forming unit Pc, a fourth image forming unit Pd, a fifth image forming unit Pe, a sixth image forming unit Pf, And a seventh image forming unit Pg, and images of different colors are formed on the transfer material through processes of electrostatic latent image formation, development, and transfer.

  The configuration of each image forming unit provided in the image forming apparatus will be described by taking the first image forming unit Pa as an example.

  The first image forming unit Pa includes a photoconductor 61a having a diameter of 30 mm as an image carrier, and the photoconductor 61a is rotated in the direction of arrow a. The primary charging device 62a has a charging magnetic brush formed on the surface of a sleeve having a diameter of 16 mm, and is disposed so as to contact the surface of the photoreceptor 61a. The laser beam 67a is irradiated by an exposure device (not shown) in order to form an electrostatic latent image on the photoreceptor 61a whose surface is uniformly charged by the primary charging device 62a. A developing device 63a as developing means for developing the electrostatic latent image carried on the photoreceptor 61a to form a color toner image holds color toner. The transfer blade 64a as a transfer means transfers the color toner image formed on the surface of the photoreceptor 61a onto the surface of the transfer material (recording material) conveyed by the belt-like transfer material carrier 88. The transfer blade 64 a is in contact with the back surface of the transfer material carrier 88 and can apply a transfer bias.

  When toner is consumed by development and the toner concentration (T / C ratio) with respect to the carrier in the two-component developer decreases, the decrease is measured by using the inductance of the coil to measure the change in the magnetic permeability of the two-component developer. The replenisher is supplied from the replenisher container 65a to the developing tank according to the amount of toner detected by the toner concentration detecting sensor 85 and consumed by the replenisher supply means. The toner concentration detection sensor 85 has a coil (not shown) inside.

The image forming apparatus shown in FIG. 13 has the same configuration as the first image forming unit Pa, and the second image forming unit Pb, the third image forming unit Pc, and the fourth image forming unit having different color toner colors. Seven image forming units of a unit Pd, a fifth image forming unit Pe, a sixth image forming unit Pf, and a seventh image forming unit Pg are provided side by side. For example, the first image forming unit Pa is yellow toner, the second image forming unit Pb is D magenta toner, the third image forming unit Pc is L magenta toner, the fourth image forming unit Pd is D cyan toner, L cyan toner is used for the image forming unit Pe, D black toner is used for the sixth image forming unit Pf, and L black toner is used for the seventh image forming unit Pg, and each color toner is transferred at the transfer section of each image forming unit. Are sequentially transferred onto the transfer material. In this step, the color toners are superimposed on each other by moving the transfer material once on the same transfer material while aligning the registration. When the transfer is completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. Then, it is sent to the fixing device 70 by a conveying means such as a conveying belt, and a final full-color image is obtained by a single fixing.

The fixing device 70 includes a pair of a fixing roller 71 having a diameter of 40 mm and a pressure roller 72 having a diameter of 30 mm. The fixing roller 71 includes heating means 75 and 76 therein. The unfixed color toner image transferred onto the transfer material passes through the pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70 and is fixed onto the transfer material by the action of heat and pressure. The Furthermore, images that are not subjected to glossing are ejected outside the device, and images that are subjected to glossing are processed by the fixing device F.
Be transported. The fixing device F will be described later.

  In FIG. 13, the transfer material carrier 68 is an endless belt-like member, and this belt-like member is moved in the direction of arrow e by 80 drive rollers. In addition, the image forming apparatus includes a transfer belt cleaning device 79, a belt driven roller 81, and a belt static eliminator 82 around the transfer material carrier 68, and the pair of registration rollers 83 uses the transfer material in the transfer material holder. It is conveyed to the transfer material carrier 68.

  As the transfer means, instead of a transfer blade that contacts the back side of the transfer material carrier, contact transfer means that can contact the back side of the transfer material carrier such as a roller-shaped transfer roller and directly apply a transfer bias can be used. It is possible to use. Further, a non-contact transfer unit that performs transfer by applying a transfer bias from a corona charger arranged in a non-contact manner on the back side of a transfer material carrier that is generally used instead of the contact transfer unit described above. It is also possible to use. However, it is more preferable to use the contact transfer means in that the amount of ozone generated when the transfer bias is applied can be controlled.

Next, an example of the fixing device F and a transfer material having a toner receiving layer on the surface layer will be described.
FIG. 8 shows an enlarged model view of the fixing device F. The fixing device F in this embodiment is a belt fixing device. The belt fixing device F includes a first fixing roller (hereinafter referred to as a fixing roller) 91 and a rotation roller (hereinafter referred to as a separation roller) as a separation roller disposed at a predetermined distance from the fixing roller 91. 93 and a rotation roller (hereinafter referred to as a tension roller) 94 as a tension roller disposed on the upper side of the separation roller 93. An endless (endless) fixing belt 97 is stretched between the three rollers 91, 93, and 94. A second fixing roller (hereinafter referred to as a pressure roller) 92 is provided as a pressure roller that is pressed against the fixing roller 91 with the fixing belt 97 interposed therebetween. An auxiliary roller 95 is provided in contact with the outer surface of the fixing belt at a position near the separation roller 93 at a fixing belt portion between the fixing roller 91 and the separation roller 93. A cooling fan 96 is provided between the fixing roller 91 and the separation roller 93 inside the fixing belt 97 and air-cools the fixing belt portion between the fixing roller 91 and the separation roller 93. The fixing roller 91, the pressure roller 92, the separation roller 93, the tension roller 94, and the auxiliary roller 95 are arranged substantially in parallel with each other.

  The fixing roller 91 has a concentric three-layer structure, and has a core portion, an elastic layer, and a release layer. The core portion is composed of an aluminum hollow pipe having a diameter of 44 mm and a thickness of 5 mm. The elastic layer is made of silicon rubber having a JIS-A hardness of 50 degrees and a thickness of 300 μm. The release layer is made of PFA having a thickness of 50 μm. A halogen lamp 98 as a heat source (roller heater) is disposed inside the hollow pipe of the core portion.

  The pressure roller 92 has the same configuration. For the elastic layer, silicon rubber having a thickness of 3 mm is used. This is to earn a fixing nip by the elastic layer. Reference numeral 99 denotes a halogen lamp as a heat source (roller heater) disposed in the hollow pipe of the core portion of the pressure roller 92.

  The fixing roller 91 and the pressure roller 92 are pressed against each other with a predetermined pressing force with the fixing belt 97 interposed therebetween, thereby forming a fixing nip portion N as a heating / pressing portion having a predetermined width in the transfer material conveyance direction. The pressure applied by the pressure roller 92 was 490 N (50 kgf) in total pressure. At this time, the width of the fixing nip portion N was 5 mm.

  Here, the surface hardness of the fixing roller 91 needs to be selected according to the fixing belt 97. If the surface hardness of the fixing roller 91 is soft, the fixing belt 97 is bent, and the toner is not sufficiently pushed into the receiving layer of the transfer material, so that a toner step remains. When the fixing belt 97 has a soft hardness, the fixing roller 91 is sufficiently hard so that the elastic layer is made thin, or only the surface layer of the PFA is removed, or only the aluminum core is used. Also good.

  The fixing roller 91 is rotationally driven at a predetermined speed in a clockwise direction indicated by an arrow by a driving mechanism (not shown). As the fixing roller 91 rotates, the fixing belt 97 rotates in the clockwise direction indicated by the arrow. The separation roller 93, tension roller 94, pressure roller 92, and auxiliary roller 95 are driven to rotate as the fixing belt 97 rotates. The tension roller 94 applies a predetermined tension to the fixing belt 97.

  Electric power is supplied to the halogen lamps 98 and 99 disposed inside the fixing roller 91 and the pressure roller 92, respectively, and the fixing roller 91 and the pressure roller 92 are internally heated by the heat generated by the halogen lamps 98 and 99, and the surface temperature is increased. Rises. The surface temperatures of the fixing roller 91 and the pressure roller 92 are respectively detected by a thermistor (not shown), and the detected temperatures of the thermistors are fed back to a control circuit (not shown). The control circuit controls the power supplied to the halogen lamps 98 and 99 so that the detected temperature input from each thermistor is maintained at a predetermined temperature set in the fixing roller 91 and the pressure roller 92, respectively. That is, the temperature of the fixing roller 91 and the pressure roller 92 are controlled to a predetermined temperature, and the temperature of the fixing nip portion N is controlled to a predetermined fixing temperature.

  The transfer material P having an unfixed toner image on the surface is introduced between the fixing belt 97 and the pressure roller 92 in the fixing nip N, and is nipped and conveyed through the fixing nip N. The unfixed toner image surface of the transfer material P faces the surface of the fixing belt 97. The transfer material P is heated and pressurized in the process of being nipped and conveyed through the fixing nip portion N to mix the color toner images and fix (fix) to the transfer material P. At the same time, the transfer material P adheres to the surface of the fixing belt 97. Thereafter, the transfer material P is conveyed in a cooling region (cooling portion) R between the fixing nip portion N and the separation roller 93 as the fixing belt 97 rotates while being in close contact with the fixing belt 97. In this cooling region R, the transfer material P is forcibly and efficiently cooled by the action of the airflow flowing through the cooling fan 96 and the air duct 96a surrounding it. An air flow perpendicular to the paper surface is generated by the cooling fan 96.

  The transfer material P in close contact with the surface of the fixing belt 97 is sufficiently cooled in the cooling region R, reaches the position of the separation roller 93, and the fixing belt in a region where the curvature of the fixing belt 97 changes by the separation roller 93. It is peeled off (curvature separation) from its surface by its own stiffness.

  The auxiliary roller 95 prevents the transfer material P from being peeled off from the surface of the fixing belt 97 in the middle of the fixing belt cooling region R from the fixing roller 91 to the separation roller 93, thereby preventing the image from being disturbed or being unable to be conveyed.

  It goes without saying that the cooling means 96 is not limited to a fan, but can be a contact-type cooling system. A Peltier element, a heat pipe, or a water circulation type cooling device may be used.

In the case where a transfer material having a toner receiving layer (image receiving layer, glossing layer) made of resin on the surface is used as the transfer material P for outputting a glossy image formed product, the transfer material passes through the fixing nip portion N. In the process of nipping and conveying, the temperature of the receiving layer rises and becomes soft due to the heat of the fixing nip N, and further, the toner is buried in the high-temperature receiving layer by applying the pressure of the fixing nip N. At the same time, the transfer material is in close contact with the surface of the fixing belt 97. Thereafter, the transfer material P is conveyed through the cooling region R along with the rotation of the fixing belt 97 in a state of being in close contact with the fixing belt 97, and is forcibly and efficiently cooled sufficiently. Then, the curvature is separated from the surface of the fixing belt 97 in a region where the curvature of the fixing belt 97 changes by the separation roller 93.
At this time, the resin media and the toner image are solidified according to the shape of the mirror-like belt surface, and the entire surface of the transfer material becomes a smooth surface, so that an image with excellent gloss can be obtained.

The transfer material P used in the present invention will be described in more detail. The most characteristic feature of this coated paper is that the outermost toner receiving layer melts near the fixing temperature. As a result, when the toner image is fixed on the transfer material, the toner image is embedded in the toner receiving layer, so that the level difference due to the toner is reduced. The transfer material P can be produced by providing a transparent resin layer on a coated paper having a pigment coating layer. As a result, there is a pigment layer in the lower layer, and a high white and smooth surface is formed, so there is no need to add a pigment to the outermost resin layer and the function of increasing the whiteness is unnecessary. The transparent resin layer can be designed giving priority to functions such as increasing the glossiness and embedding a toner image. Furthermore, there is an advantage that it is not necessary to newly manufacture a coated paper. As such a transfer material, POD super gloss coated paper manufactured by Oji Paper Co., Ltd. is on the market.

Introducing an example of a specific method for producing the transfer material, the coated paper having the above-mentioned pigment coating layer formed on a base material as a base paper, a thermoplastic resin on one side or both sides of the base paper, A desired coated paper can be produced by coating using a gravure coater or the like.
As the resin constituting the transparent resin layer, a polyester resin, a styrene-acrylic ester resin, a styrene-methacrylic ester resin, or the like can be used, and it is particularly preferable to use a polyester resin. The following are illustrated as a polyhydric alcohol component and polyhydric carboxylic acid component which comprise a polyester resin.

  Polyhydric alcohol components include ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, a monomer obtained by adding olefin oxide to bisphenol A, and the like can be used.

  Examples of the polyvalent carboxylic acid component include maleic acid, maleic anhydride, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid, dodecyl succinic acid, n-octyl succinic acid, and n-dodecyl succinic acid. Acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2 -Methyl-2-methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, trimellitic acid, pyromellitic acid, lower alkyl esters of these acids, and the like can be used. .

The polyester resin constituting the transparent resin layer is synthesized by polymerization of one or more of the polyhydric alcohol components and one or more of the polyvalent carboxylic acid components. As the resin component of the toner, a polyester resin is used in color toners, and a styrene-acrylic resin is mainly used in monochrome toners. It is preferable to select a highly compatible one.

Accordingly, one or a mixture of two or more of polyester resin, styrene-acrylic acid ester resin, styrene-methacrylic acid ester resin and the like is used depending on the purpose.
Furthermore, the transparent resin layer can contain a pigment, a release agent, a conductive agent, and the like within a range that does not impair the transparency. In that case, the resin content of the main component is preferably 80% by mass or more with respect to the total mass of the resin layer. Further, the transparent resin layer preferably has a composition adjusted so that the surface electrical resistance is 8.0 × 10 ⁸ Ω or more at a temperature of 20 ° C. and a relative humidity of 85%.

  In addition, it is not limited to such a manufacturing method, as long as it is a coated paper provided with a thermoplastic resin layer having a melting characteristic whose surface melts near the fixing temperature, it is not always necessary to have a multilayer structure, such as a pigment It goes without saying that various additives may be added.

Hereafter, the measuring method of each physical property in this invention is demonstrated.
<Measurement of brightness L ^* in powder state>
L ^* in the toner in the powder state is a spectral color difference meter “S” according to JIS Z-8722.
E-2000 "(manufactured by Nippon Denshoku Industries Co., Ltd.) is used, and the light source is measured with a C light source with a 2-degree field of view. The measurement is performed according to the attached instruction manual. For standard adjustment of the standard plate, it is preferable to perform the measurement through a glass of 2 mm thickness and φ30 mm in an optional powder measurement cell. More specifically, the measurement is performed in a state in which a cell filled with sample powder (toner) is placed on a sample table (attachment) for powder sample of the spectroscopic color difference meter. Before placing the cell on the sample table for powder sample, fill the powder sample with 80% or more of the internal volume in the cell, and apply 1 vibration / second on the vibration table for 30 seconds. Measure with

<Measurement of weight average particle diameter and particle size distribution of toner>
In the present invention, the weight average particle size and particle size distribution of the toner can be measured using a Coulter Counter TA-II type (manufactured by Coulter). It is also possible to use a Coulter Multisizer (manufactured by Coulter). In the measurement, an electrolytic solution is used, and a 1% NaCl aqueous solution is used for this electrolytic solution. The 1% NaCl aqueous solution may be prepared using primary sodium chloride, or a commercially available product such as ISOTON R-II (manufactured by Coulter Scientific Japan) may be used.
As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume and the number of toner particles of 2.00 μm or more are measured and measured by the measuring device using a 100 μm aperture as the aperture. The distribution and the number distribution are calculated to determine the weight average particle diameter (D4) (the median value of each channel is the representative value for each channel).
As channels, 2.00 to 2.52 μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm; 4.00 to 5.04 μm; 5.04 to 6.35 μm; 6.35 to 8. 00μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32.00 μm; 13 channels of 32.00-40.30 μm are used.

<Measurement of average circularity of toner>
The average circularity of the toner is measured using a flow type particle image measuring device “FPIA-2100 type” (manufactured by Sysmex Corporation), and is calculated using the following equation.

Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define. The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm).
In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity.
The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following equation, where ci is the circularity (center value) at the dividing point i of the particle size distribution and m is the number of measured particles.

  Further, the circularity standard deviation SD is calculated from the following equation where the average circularity C, the circularity ci of each particle, and the number of measured particles are m.

  In addition, “FPIA-2100”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity and the circularity standard deviation. The degrees 0.40 to 1.00 are divided into classes equally divided every 0.01, and the average circularity and the circularity standard deviation are calculated using the center value of the division points and the number of measured particles.

  As a specific measuring method, 10 ml of ion-exchanged water from which impure solids have been removed in advance is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, followed by further measurement. Add 0.02 g of sample and disperse uniformly. As a means for dispersion, an ultrasonic disperser “Tetora 150 type” (manufactured by Nikka Ki Bios Co., Ltd.) is used, and dispersion treatment is performed for 2 minutes to obtain a measurement dispersion. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more. In order to suppress variation in circularity, the installation environment of the apparatus is controlled at 23 ° C. ± 0.5 ° C. so that the temperature inside the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C. Preferably, autofocus is performed using 2 μm latex particles every 2 hours.

To measure the circularity of the toner particles, the flow type particle image measuring device is used, and the concentration of the dispersion is readjusted so that the toner particle concentration at the time of measurement is 3000 to 10,000 particles / μl. Measure more than one. After the measurement, using this data, data having an equivalent circle diameter of less than 2 μm is cut to determine the average circularity of the toner particles.
Furthermore, “FPIA-2100”, which is a measuring device used in the present invention, improves the magnification of the processed particle image compared to “FPIA-1000”, which has been used for calculating the shape of the toner. Furthermore, the accuracy of toner shape measurement has been improved by improving the processing resolution of the captured image (256 × 256 → 512 × 512), thereby achieving more reliable capture of fine particles. Therefore, when it is necessary to measure the shape more accurately as in the present invention, the FPIA 2100 that can obtain information on the shape more accurately is more useful.

<Measurement of toner aggregation degree>
The degree of toner aggregation was measured using a powder tester PT-R (manufactured by Hosokawa Micron). Specifically, on the shaking table, three stages of sieves are set in the order of 150 μm, 75 μm, and 38 μm from the top, the vibration amplitude is 0.6 mm, the vibration time is 15 seconds, and the toner is accurately weighed 5 g. 2
Gently shake what was left at 3 ° C and 60% RH for 24 hours or more. After stopping vibration, measure the mass remaining on each sieve. And a, b, and c are defined as follows.
a = (the amount of toner remaining on the upper screen) ÷ 5 (g) × 100
b = (amount of toner remaining on the middle screen) ÷ 5 (g) × 100 × 0.6
c = (amount of toner remaining on the lower screen) ÷ 5 (g) × 100 × 0.2
The degree of aggregation (%) was calculated as a + b + c. A smaller degree of aggregation indicates a toner with better fluidity.

<Measurement method of true specific gravity of carrier>
The true specific gravity of the carrier in the present invention was measured according to JIS Z2504 using a true denser (manufactured by Seishin Enterprise).

<Measurement method of carrier particle size>
The particle size of the carrier is measured by a laser diffraction particle size distribution analyzer SALD-300V (manufactured by Shimadzu Corporation), and a 50% particle size (D50) based on volume distribution is calculated.

<Measurement of maximum temperature of maximum endothermic peak of wax>
The maximum endothermic peak of toner and wax is measured according to ASTM D3418-82 using a differential scanning calorimeter (DSC measuring apparatus) DSC2920 (manufactured by TA Instruments Japan).
The measurement sample is precisely weighed in an amount of 3 to 7 mg, preferably 4 to 5 mg. It is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 10 ° C./min at normal temperature and humidity in a measurement range of 30 to 200 ° C. For the peak temperature of the wax, the temperature at which the peak is reached in the process of temperature increase II is measured.
Temperature curve: Temperature increase I (30 ° C. to 200 ° C., temperature increase rate 10 ° C./min)
Temperature drop I (200 ° C-30 ° C, temperature drop rate 10 ° C / min)
Temperature increase II (30 ° C. to 200 ° C., temperature increase rate 10 ° C./min)

<Measurement of toner charge distribution>
E-SPART Analyzer MODEL EST-III ver. Using 9.03 (manufactured by Hosokawa Micron Corporation), the toner charge amount distribution is measured as follows.
The developer described above is held in a two-component feeder (developer holding table having a rotating disk with a built-in magnet) attached to the E-SPART Analyzer. Next, nitrogen gas is sprayed from the air nozzle to the developer held magnetically in the two-component feeder to blow off only the toner, and only the toner is sucked into the E-SPART Analyzer measuring section through the sample introduction tube under the two-component feeder. Then, the particle diameter d (μm) and the charge amount q (femto-C) are measured. A q / d distribution is obtained based on this data. In addition, the measurement conditions of E-SPART Analyzer in this embodiment were as follows.
Number of toner particles measured: 3000 pcs PM VOLTAGE: -460V
FIELD VOLTAGE: 100V
Measuring unit suction flow rate: 6.6 × 10 ⁻⁶ m ³ / s
Two-component feeder rotation speed: 0.025 to 0.050 s ^-1
Rectifier DC voltage for electromagnetic coil: 90V
Nitrogen gas blow pressure: 20 kPa
Nitrogen gas blow time: 1 second Nitrogen gas blow interval: 4 seconds

<Measuring method of glass transition temperature of resin>
The glass transition temperature (Tg) of the resin was measured in accordance with ASTM D3418-82 using a differential scanning calorimeter (DSC apparatus) and DSC2920 (TA Instruments Japan).
The measurement sample was used by weighing 10 mg. An empty aluminum pan was used as a reference.

<Measurement of molecular weight of resin by GPC>
The molecular weight of the chromatogram by gel permeation chromatography (GPC) is measured under the following conditions.
The column was stabilized in a 40 ° C. heat chamber, and tetrahydrofuran (THF) as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min, and the sample concentration was adjusted to 0.05 to 0.6% by mass. About 50 to 200 μl of THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number (retention time). Examples of standard polystyrene samples for preparing a calibration curve include those manufactured by Tosoh Corporation or Pressure Chemical Co. The molecular weights produced are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8 .6
It is appropriate to use × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.
As the column, in order to accurately measure a molecular weight region of 10 ^{3 to} 2 × 10 ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, shodex GPC KF-801, 802, 803 manufactured by Showa Denko , 804, 805, 806, and 807, and the combination of μ-styragels 500, 103, 104, and 105 manufactured by Waters.

<Measurement method of magnetization intensity of magnetic carrier>
The strength of magnetization of the magnetic carrier can be obtained by a vibrating magnetic field type magnetic property device VSM (Vibrating sample magnetometer) or a direct current magnetization characteristic recording device (BH tracer). Preferably, it can measure with an oscillating magnetic field type magnetic property apparatus. Examples of the oscillating magnetic field type magnetic property apparatus include an oscillating magnetic field type magnetic property automatic recording apparatus BHV-30 manufactured by Riken Denshi Co., Ltd. In this invention, it measured in the following procedures using this apparatus. The cylindrical plastic container is filled with the carrier sufficiently dense, while 1000 / 4π (kA / m)
An external magnetic field of (1000 oersted) is created, and in this state, the magnetization moment of the carrier filled in the container is measured. Further, the actual mass of the carrier filled in the container is measured to determine the magnetization strength (Am ² / kg) of the carrier.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples. In the following examples, “parts” and “%” are “parts by mass” and “% by mass” unless otherwise specified.

<Production example of polyester resin>
In a reaction vessel equipped with a thermometer, a stirrer, a condenser and a nitrogen introduction tube, 35 parts by mass of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2 ) -2,2-bis (4-hydroxyphenyl) propane 20 parts by mass, terephthalic acid 23 parts by mass, trimellitic anhydride 7 parts by mass, fumaric acid 15 parts by mass and 2-ethylhexanoic acid tin 0.02 parts by mass. Then, after replacing the inside of the reaction vessel with nitrogen gas, the temperature was gradually raised while stirring, and a condensation reaction was carried out at 215 ° C. for 4 hours to obtain a polyester resin. The Tg of the polyester resin was 58 ° C., the weight average molecular weight (Mw) was 65000, and the number average molecular weight (Mn) was 4500.

<Example of toner particle production>
(D / L cyan toner particles 1 to 5, 10 and 11, D / L magenta toner particles 1 to 5, 10 and 11, yellow toner particles 1 to 5, 10 and 11, D black toner particles 1 to 5, 10 and 11 and production examples of L black toner particles 1 to 5, 11 and 12)
With respect to 100 parts by mass of the polyester resin, the toner materials shown in Table 1 were sufficiently premixed by a Henschel mixer with the composition shown in Table 1. The obtained mixture was melt-kneaded with a twin screw extruder, the melt-kneaded product was cooled, and the cooled product was coarsely pulverized to a particle size of about 1-2 mm using a hammer mill. Next, the coarsely pulverized product was finely pulverized to a particle size of 20 μm or less with an air jet type fine pulverizer.
Thereafter, D cyan toner particles 1, 2, 4, and 10, D magenta toner particles 1, 2, 4, and 10, yellow toner particles 1, 2, 4, and 10, D black toner particles 1, 2, 4, and 10, L For the cyan toner particles 1 to 4, 10 and 11, the L magenta toner particles 1 to 4, 10 and 11, and the L black toner particles 1 to 4, 11 and 12, the finely pulverized products obtained above are shown in FIGS. Surface treatment was performed using the processing apparatus shown in FIG. 7 to obtain toner particles.
As the surface treatment conditions, the tip peripheral speed of the classification rotor is set to 110 m / sec for the purpose of removing fine particles, and the tip peripheral speed of the dispersion rotor is set to 120 to 140 m / sec for the purpose of adjusting the circularity. Then, the surface treatment was carried out for 45 seconds (after the finely pulverized product was charged from the raw material supply port 39, after the treatment for 45 seconds, the discharge valve 41 was opened and taken out as a treated product).
At that time, twelve square disks 33 were installed on the top of the dispersion rotor 32, the distance between the guide ring 36 and the square disk 33 on the dispersion rotor 32 was 10 mm, and the distance between the dispersion rotor 32 and the liner 34 was 5 mm. . The blower air volume was 14 m ³ / min, the temperature of the refrigerant passed through the jacket and the cold air temperature T1 were −20 ° C.
Also, D cyan toner particles 3, 5 and 11, D magenta toner particles 3, 5 and 11, yellow toner particles 3, 5 and 11, D black toner particles 3, 5 and 11, L cyan toner particles 5 and L magenta The toner particles 5 and the L black toner particles 5 were classified using an air classifier (elbow jet classifier: manufactured by Nittetsu Mining Co., Ltd.) instead of the surface treatment device, thereby obtaining toner particles.

<Toner Particle Production Example 6>
(Production example of D / L cyan toner particles 6, D / L magenta toner particles 6, yellow toner particles 6 and D / L black toner particles 6)
The D / L cyan toner particle 1, the D / L magenta toner particle 1, the yellow toner particle 1 and the D / L black toner particle 1 manufactured in the toner particle manufacturing example 1 are combined with a surfing system manufactured by Nippon Pneumatic Co., Ltd. In addition, toner particles were spheroidized. The temperature in the tank was set to 300 ° C., and the residence time was set to 0.5 seconds.

<Toner Particle Production Example 7>
(Production example of D / L cyan toner particles 7, D / L magenta toner particles 7, yellow toner particles 7 and D / L black toner particles 7)
[Synthesis of toner particle binder]
726 parts by mass of bisphenol A ethylene oxide 2-mole adduct, 274 parts by mass of isophthalic acid and 2 parts by mass of dibutyltin oxide were placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. After reacting for 5 hours, the reaction was allowed to proceed for 5 hours under a reduced pressure of 10 to 15 mmHg. This was cooled to 160 ° C., 32 parts by mass of phthalic anhydride was added and reacted for 2 hours. Furthermore, this was cooled to 80 ° C. and reacted with 190 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-containing prepolymer (1). Next, 278 parts by mass of this prepolymer (1) and 14 parts of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester (1) having a weight average molecular weight of 63,500.
In the same manner as above, 720 parts by mass of bisphenol A ethylene oxide 2-mole adduct and 280 parts by mass of terephthalic acid were subjected to polycondensation at 230 ° C. for 8 hours under normal pressure, and then reacted at a reduced pressure of 10 to 15 mmHg for 5 hours to obtain a peak molecular weight of 4900. A polyester (a) which was not modified was obtained.
200 parts by mass of urea-modified polyester (1) and 800 parts by mass of unmodified polyester (a) are dissolved and mixed in 2000 parts by mass of an ethyl acetate / ethyl methyl ketone (MEK) (1/1) mixed solvent, and a toner binder ( An ethyl acetate / MEK solution of 1) was obtained. Part of the mixture was dried under reduced pressure to isolate toner binder (1). Tg was 62 ° C.

(Production of toner particles)
In a beaker, 240 parts by mass of the above-mentioned toner binder (1) in ethyl acetate / MEK solution, 20 parts by mass of pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 25 cps), colorant shown below, 3,5-di -2 parts by mass of an aluminum tert-butylsalicylate compound was added and stirred at 60 ° C. and 12,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and uniformly dissolved and dispersed. In a beaker, 706 parts by mass of ion-exchanged water, 294 parts by mass of hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.) and 0.2 parts by mass of sodium dodecylbenzenesulfonate were uniformly dissolved. Next, the temperature was raised to 60 ° C., and the toner material solution was added and stirred for 10 minutes while stirring at 12000 rpm with a TK homomixer. The mixture was then transferred to a Kolben equipped with a stir bar and a thermometer, and the temperature was raised to 98 ° C. to remove the solvent. After filtration, washing and drying, air classification was performed, and the weight average particle size was 6.5 μm. Toner particles were obtained.
The colorant for each toner particle is as follows.
D cyan toner: C.I. I. Pigment Blue 15: 3 5.0 parts by mass L Cyan toner: C.I. I. Pigment Blue 15: 3 0.8 parts by mass D Magenta Toner: C.I. I. Pigment Red 122 7.0 parts by mass L magenta toner: C.I. I. Pigment Red 122 1.0 part by mass Yellow Toner: C.I. I. Pigment Yellow 74 7.0 parts by mass D black toner:
Carbon black / C.I. I. Pigment Blue 15: 3 5.0 / 0.5 parts by mass L black toner:
Carbon black / C.I. I. Pigment Blue 15: 3 0.8 / 0.08 parts by mass

<Production Example 8 of Toner Particles>
(Production example of D / L cyan toner particle 8, D / L magenta toner particle 8, yellow toner particle 8 and D / L black toner particle 8)
[Preparation of acidic polar group-containing polymer resin]
Styrene monomer (St) 80 parts by mass Butyl acrylate (BA) 20 parts by mass Acrylic acid (AA) 5 parts by mass

100 parts by mass of water The above monomer mixture is added to 1 part by weight of Emulgen 950 (manufactured by Kao Corporation), 1 part by weight of Neogen R (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and potassium persulfate is used as a catalyst. Then, polymerization was carried out at 70 ° C. for 8 hours with stirring to obtain an acidic polar group-containing resin emulsion having a solid content of 50%.

(Preparation of toner particles)
Acidic polar group-containing resin emulsion 200 parts by mass Various colorants Polyethylene wax dispersion 20 parts by mass (Chemical WF-640 manufactured by Mitsui Petrochemical Co., Ltd.)
3,5-Di-tert-butylsalicylic acid aluminum compound 2 parts by weight Water A mixture of 350 parts by weight or more was heated to 25 ° C while stirring with a disper. The dispersion was then stirred for about 2 hours and then heated to 60 ° C., which was adjusted to pH 8.0 with ammonia. Further, when this dispersion was heated to 90 ° C. and kept at this temperature for 5 hours, particles having a weight average particle diameter of about 6.5 μm were obtained. The particle dispersion was cooled, separated, washed with water, and dried. When this particle was observed with a scanning electron microscope, it was observed that it was composed of secondary particles of polymer particles and magnetic fine particles.
The colorant for each toner particle is as follows.
D cyan toner: C.I. I. Pigment Blue 15: 3 5.0 parts by mass L Cyan toner: C.I. I. Pigment Blue 15: 3 0.8 parts by mass D Magenta Toner: C.I. I. Pigment Red 122 7.0 parts by mass L magenta toner: C.I. I. Pigment Red 122 1.0 part by mass Yellow Toner: C.I. I. Pigment Yellow 74 7.0 parts by mass D Black Toner: Carbon Black Carbon Black / C.I. I. Pigment Blue 15: 3 5.0 / 0.5 parts by mass L black toner:
Carbon black / C.I. I. Pigment Blue 15: 3 0.8 / 0.08 parts by mass

<Production Example 9 of Toner Particles>
(Production example of D / L cyan toner particle 9, D / L magenta toner particle 9, yellow toner particle 9 and D / L black toner particle 9)
To 710 parts by mass of ion-exchanged water, 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution was added and heated to 60 ° C., and then at 14000 rpm using a TK homomixer (made by Tokushu Kika Kogyo). Stir. To this, 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium having a pH of 5.9 containing a calcium phosphate compound.
・ Styrene 160 parts by mass ・ n-butyl acrylate 36 parts by mass ・ Various colorants
・ 3,5-di-tert-butylsalicylic acid aluminum compound 2 parts by mass ・ Ester wax (Mw: 500, Mn: 400, Mw / Mn: 1.25, peak temperature of DSC maximum endothermic peak: 75 ° C.) 15 parts by mass The above material was heated to 60 ° C., and uniformly dissolved and dispersed at 13000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). Into this, 10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition was put into the aqueous medium, and stirred at 10,000 rpm for 10 minutes in a Claire mixer (manufactured by M Technique Co., Ltd.) at 65 ° C. in an N ₂ atmosphere. Granulated. Thereafter, while stirring the aqueous medium with a paddle stirring blade, the temperature was raised to 80 ° C., and the polymerization reaction was carried out for 8 hours while maintaining the pH at 6.
After completion of the polymerization reaction, the mixture is cooled, and hydrochloric acid is added so that the pH is 1.5 to dissolve calcium phosphate, followed by filtration, washing with water, drying, and classification to obtain polymerizable toner particles having a weight average particle diameter of about 6.5 μm. Obtained.
The colorant for each toner particle is as follows.
D cyan toner: C.I. I. Pigment Blue 15: 3 5.0 parts by mass L Cyan toner: C.I. I. Pigment Blue 15: 3 0.8 parts by mass D Magenta Toner: C.I. I. Pigment Red 122 7.0 parts by mass L magenta toner: C.I. I. Pigment Red 122 1.0 part by mass Yellow Toner: C.I. I. Pigment Yellow 74 7.0 parts by mass D black toner:
Carbon black / C.I. I. Pigment Blue 15: 3 5.0 / 0.5 parts by mass L black toner:
Carbon black / C.I. I. Pigment Blue 15: 3 0.8 / 0.08 parts by mass

<Example 10 of production of L black toner particles>
L black toner particles 10 were obtained in the same manner as in the production example of L black toner particles 1 except that the colorant was only 0.8 parts by mass of carbon black with respect to L black toner particles 1.

<Toner Production Examples 1 to 12>
<External addition of fluidity improver>
To 100 parts by mass of the obtained toner particles, a fluidity improver shown in Tables 2 to 8 is added and mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain a toner. It was. The physical properties of the toner are shown in Tables 2-8.

<Lightness L * of each color toner and a *, b * of black toner>
The lightness L * of each color toner is 35-40 for D cyan toner and 58-63 for L cyan toner.
D magenta toner was 30 to 35, L magenta toner was 54 to 59, yellow toner was 80 to 85, D black toner was 10 to 15, and L black toner was 40 to 45.
For each D / L black toner, a * and b * in the powder state were in the range of 0 to 5 except for the L black toner 10. The L black toner 10 had a * = 1.56 and b * = 5.41.

<Example of carrier production>
(Example of manufacturing carrier A)
4.0% by mass of a silane coupling agent (3- (2-aminoethylaminopropyl) trimethyl) with respect to a magnetite powder having a number average particle size of 0.30 μm and a hematite powder having a number average particle size of 0.30 μm. Methoxysilane) was added, and the mixture was stirred at a high speed at 100 ° C. or higher in the container to treat each fine particle.
・ Phenol 10 parts by mass ・ Formaldehyde solution 6 parts by mass (formaldehyde 40%, methanol 10%, water 50%)
・ Processed magnetite 77 parts by mass ・ Processed hematite 7 parts by mass The above material, 5% by mass of 28% ammonia water, and 20 parts by mass of water are placed in a flask, and heated to 85 ° C. for 30 minutes while stirring and mixing. The resulting phenol resin was cured by a polymerization reaction for 3 hours. Thereafter, the cured phenol resin was cooled to 30 ° C., water was further added, the supernatant was removed, the precipitate was washed with water, and then air-dried. Subsequently, this was dried under reduced pressure (5 mmHg or less) at a temperature of 60 ° C. to obtain a spherical magnetic substance-containing resin carrier core in which the magnetic substance was dispersed.
As a coating material, a copolymer of methyl methacrylate and perfluorooctyl acrylate (copolymerization ratio (mass% ratio) 8: 2, weight average molecular weight 45,000) is used, and this is 100 mass of the magnetic material dispersed resin core at the time of coating. A carrier coat solution containing 10% by mass of a copolymer of methyl methacrylate and perfluorooctyl acrylate was prepared using a mixed solvent of methyl ethyl ketone and toluene as a solvent so as to be 1 part by mass with respect to parts. In addition, 0.4 parts by mass of melamine resin (number average particle size 0.2 μm) and 0.5 parts by mass of carbon black (number average particle size 30 nm, DBP oil absorption 50 ml / 100 g) may be added to the carrier coat solution using a homogenizer. Mix. Next, the magnetic material-dispersed resin core is added to the mixed solution, and the solvent is volatilized at 70 ° C. while continuously applying shear stress to the mixed solution, and the methyl methacrylate and perfluorooctyl acrylate are applied to the surface of the magnetic material-dispersed resin core. And a copolymer.
The resin-coated magnetic material-dispersed resin core coated with a copolymer of methyl methacrylate and perfluorooctyl acrylate is heat-treated by stirring at 100 ° C. for 2 hours, cooled, crushed, and classified with a 200 mesh sieve. Thus, a magnetic carrier A having a number average particle diameter of 35 μm and a true specific gravity of 3.7 g / cm ³ was obtained. Table 9 shows the physical properties of the carrier.

(Example of manufacturing carrier B)
Carrier B was prepared in the same manner as carrier A except that melamine resin and carbon black were not added to the coating resin. Table 9 shows the physical properties of the carrier.

(Example of manufacturing carrier C)
As a ferrite component, 26.0 mol% MnO, 4.0 mol% MgO, 69.0 mol% Fe ₂ O ₃ and 1.0 mol% SrCO ₃ were pulverized and mixed in a wet ball mill for 5 hours, and dried. The obtained dried product was held at 900 ° C. for 3 hours and calcined. This temporarily fired product was pulverized for 7 hours with a wet ball mill to a thickness of 2 μm or less. A binder (polyvinyl alcohol) is added to this slurry in an amount of 2.0% by mass based on the total mass of the dried pulverized product, and then granulated and dried by a spray dryer (manufacturer: Okawara Kako), and a volume-based 50% particle size. A granulated product having (D50) of about 42 μm was obtained. This granulated product was put in an electric furnace, and held at 1300 ° C. for 3 hours in a mixed gas in which the oxygen concentration in the nitrogen gas was adjusted to 2.0 vol%, followed by firing. The obtained fired product was crushed and further sieved with a sieve (aperture 75 μm) to obtain a magnetic carrier core.
Monomer 55 having 2 parts by mass of a methyl methacrylate macromer having an ethylenically unsaturated group at one end, and — (CH ₂ —CH) —CO—O—CH ₂ —CH ₂ — (CF ₂ ) ₇ —CF ₃ as a unit Part by mass and 43 parts by mass of methyl methacrylate were added to a four-necked flask equipped with a reflux condenser, a thermometer, a nitrogen suction tube, and a friction stirrer. To this, 90 parts by mass of toluene, 110 parts by mass of methyl ethyl ketone, and 2.0 parts by mass of azobisisovaleronitrile were added, and the mixture was maintained at 70 ° C. for 10 hours under a nitrogen stream. The graft copolymer solution (solid content: 33% by mass) Got.
2 parts by mass of melamine resin (number average particle size 0.2 μm) and 200 parts by mass of toluene were mixed well with a homogenizer with respect to 60 parts by mass of the graft copolymer solution (solid content 33% by mass) to obtain a coating solution. . Next, 2000 parts by mass of the core particles are stirred while continuously applying a shearing stress, the coating solution is gradually added, and the solvent is volatilized while maintaining the temperature at 70 ° C. while stirring, to the surface of the magnetic carrier core. Resin coating was performed. The resin-coated carrier core particles were heat-treated with stirring at 100 ° C. for 2 hours, cooled and crushed, and then sieved with a sieve having an aperture of 74 μm, and a 50% particle size (D50) of 42 μm based on volume distribution. Carrier C having a true specific gravity of 4.0 g / cm ³ was obtained. Table 9 shows the physical properties of the carrier.

(Example of manufacturing carrier D)
As a ferrite component, 20.0 mol% MgO, 58.0 mol% Fe ₂ O ₃ and 22.0 mol% SrCO ₃ were adjusted in the same manner as the carrier C except that the main firing temperature was changed to 1100 ° C. A magnetic carrier core having a standard 50% particle size (D50) of 38 μm was obtained.
For the above core,
Straight silicone resin (KR255 manufactured by Shin-Etsu Chemical Co., Ltd. (solid content conversion)) 100 parts by mass Silane coupling agent (γ-aminopropylethoxysilane) 10 parts by mass Carbon black (CB) (number average particle size 30 nm, DBP oil absorption 50 ml / 100 g) 10 parts by mass The above components were mixed with 300 parts by mass of xylene to obtain a magnetic carrier resin coating solution. While stirring the resin coating solution using a fluidized bed heated to 70 ° C., the magnetic carrier core was coated with a solvent so that the mass of the straight silicone resin was 12.0% by mass with respect to the mass of the magnetic carrier core. A removal operation was performed. Furthermore, after processing for 2.5 hours at 230 ° C. using an oven, pulverization and classification with a sieve (aperture 75 μm) were performed to obtain a magnetic carrier D. Table 9 shows the physical properties of the carrier.

(Example of manufacturing carrier E)
Add 2.0% of polyvinyl alcohol using magnetite with a number average particle size of 0.25 μm as a binder, granulate with a spray dryer, and calcine at 650 ° C. for 2 hours in a nitrogen gas atmosphere with an oxygen gas concentration of 0.5%. Core particles were obtained.
Using the obtained core particles,
Methanol 290 parts by mass Polyhydroxystyrene 10 parts by mass The above core particles 60 parts by mass Methyl methacrylate 35 parts by mass Perfluoropropyl methyl methacrylate 5 parts by mass 2,2′-azobisisobutyronitrile 5 parts by mass

The composition consisting of the above was put into a reaction vessel, stirred at 100 ° C. for 2 hours, heat-treated, cooled, crushed, classified with a 200 mesh sieve, and 50% particle size based on volume distribution (D50) A carrier E of 43 μm and a true specific gravity of 2.0 g / cm ³ was obtained. Table 9 shows the physical properties of the carrier.

(Example of manufacturing carrier F)
Fe ₂ O ₃ : 50 mol%, CuO: 25 mol%, ZnO: 25 mol% were wet mixed in a ball mill for 24 hours, dried and pulverized, calcined at 800 ° C. for 2 hours, and 0% using a pulverizer. Crushed to about 1 to 1.0 mm. Furthermore, it is wet pulverized with a ball mill to form a slurry, 1.0% of polyvinyl alcohol is added as a binder, granulated with a spray dryer, baked at 1020 ° C. for 12 hours in an air atmosphere, and sieved with a sieve having an opening of 250 μm. Then, coarse particles were removed to obtain 40 μm core particles.
Then
Toluene 1000 parts by mass Silicone resin (SR2410 manufactured by Toray Dow Corning) 97 parts by mass Aminopropyltrimethoxysilane 3 parts by mass The above components were mixed to prepare a resin liquid. Next, the formulation of the solution is adjusted so that the resin solid content is 2% by mass with respect to the particles, and coating is performed with a fluidized bed coating apparatus (SPIR-A-FLOW, manufactured by Freund Sangyo Co., Ltd.), and further 140 ° C. Was baked for 2 hours and sieved with a sieve having an aperture of 74 μm to obtain a carrier F having a volume distribution standard 50% particle size (D50) of 40 μm and a true specific gravity of 5.0 g / cm ³ . Table 9 shows the physical properties of the carrier.

<Preparation of two-component developer and developer for replenishment>
Each toner used in the present invention produced in Toner Production Examples 1 to 12 and the carrier shown in Table 9 has a toner density [toner density = toner mass / (carrier mass + toner mass) × 100] of 7. The two-component developer of the present invention was obtained by uniformly mixing so as to be in mass%.
Further, each toner manufactured in Toner Production Examples 1 to 12 and the carrier shown in Table 9 are mixed so as to have a C / T mass ratio (carrier / toner mass ratio) shown in Tables 10 to 16 for replenishment. A developer was obtained.

<Examples 1-19, Comparative Examples 1-6>
The image forming apparatus used in this embodiment will be described. FIG. 13 is a schematic view of an image forming apparatus applied to this embodiment, and FIG. 11 is a schematic view of a developing unit of the image forming apparatus.
The image forming apparatus shown in FIG. 13 has yellow toner in the first image forming unit Pa, D magenta toner in the second image forming unit Pb, L magenta toner in the third image forming unit Pc, and fourth image forming. D cyan toner is used for the unit Pd, L cyan toner is used for the fifth image forming unit Pe, D black toner is used for the sixth image forming unit Pf, and L black toner is used for the seventh image forming unit Pg. Transfer of each color toner onto the transfer material is sequentially performed at the transfer portion of the unit.
As the fixing device 70, a heat roll type fixing device having no oil application function was used. In addition, both the upper roller and the lower roller having a fluorine resin surface layer were used. The fixing temperature was set to 180 ° C. and the nip width was set to 10 mm.
In the full color mode for photographic image quality, after passing through the fixing device 70, the fixing device F is further passed. Details of the fixing device F are as shown in FIG. The fixing belt 97 is made of a polyimide resin having silicon rubber as an elastic layer and a polyimide silicon resin film coated thereon as a release layer. The fixing temperature was 190 ° C., and the temperature cooled by the cooling fan was 40 ° C.
As shown in FIG. 11, the developing means of the full-color image forming apparatus shown in FIG. 13 has a developer carrier, a developing tank, a replenisher supplying means, and a developer discharging means, and the copying operation is repeated. The toner density detection sensor 85 detects that the toner density in the developing tank has dropped, and the replenisher supply means performs feedback control so that the toner density falls within an appropriate range necessary for development, and replenishes from the replenisher container 65a. The agent is supplied to the developing device 63a.
The two-component developer was put in a developing device, the replenishing developer was put in a replenishing agent container, and left overnight in an environment of normal temperature and humidity (23 ° C., 60% RH). Thereafter, a developing device was set in the above-described image forming apparatus, and image output was performed as shown below while sequentially supplying a replenishing developer so that the toner density was constant.
This image forming apparatus also uses a magnetic brush developer, and performs development while the magnetic brush is in contact with the photosensitive member 21 while applying an alternating voltage to the developer carrying member to form an alternating electric field in the developing region. The distance between the developer carrying member (developing sleeve) 6 and the photosensitive member 21 (SD distance) was 350 μm.
The voltage between the peaks of the alternating electric field formed by applying the developing bias was 1800 V, the frequency was 3000 Hz, and the waveform of the alternating voltage for forming the alternating electric field was a rectangular wave. By using a two-component developer having a well-charged toner, the fog removal voltage (Vback) was 140 V, and the contrast potential was appropriately adjusted according to the image density.

<Image output method 1>
Plain paper (color laser copier paper TKCLA4; manufactured by Canon) is used as a transfer material, and a halftone image of gradation data 190 is output in a single color mode of cyan, magenta, and black (a single color is output using both L / D toners). Also, 20000 sheets were output at a speed of 60 sheets (A4 size) / min in the monochrome mode of yellow.

<Image output method 2>
The above plain paper is used as a transfer material, and 4000 sheets are output at a speed of 60 sheets (A4 size) / min in normal full color mode (without using L toner) of cyan, magenta, yellow and black, and then the transfer material is Oji. Using POD super gloss coated paper manufactured by Paper Manufacturing Co., Ltd., 1000 sheets were output at a speed of 15 sheets (A4 size) / min in a full color mode (using L toner) for photographic image quality. In the full color mode for photographic image quality, the consumption amount of L toner was twice that of D toner.
Four sets of the above were output, and a total of 20000 images were output.
The combinations of the two-component developers and the replenishment developers in Examples 1 to 15 and Comparative Examples 1 to 5 are shown in Table 17, the combinations of Example 16 in Table 18, and the combinations of Example 17 in Table 19. Table 20 shows the combinations of Examples 18 and 19 and Comparative Example 6, respectively.

Next, each evaluation item will be described.
(1) Evaluation of Dispersion of Charge Distribution After the image output of 20 sheets was completed by the image output method 1, 1 g of the two-component developer on the developing sleeve was collected, and E-SPART Analyzer MODEL EST-III ver. The variation of the charge distribution was evaluated based on the half-value width (femto-C / μm) of the main peak in the q / d distribution (see FIG. 14) measured by 9.03 (manufactured by Hosokawa Micron).
A: Less than 0.20 (A very stable image can be output over a long period of time)
B: 0.20 or more and less than 0.25 (Although there is some variation in the charge distribution, a stable image can be output)
C: 0.25 or more and less than 0.30 (the image density and the color are slightly fluctuated somewhat, and there is a sense of incongruity)
D: 0.30 or more (Image density and color may vary for each output image, and fogging may occur) The results are shown in Tables 10 to 16.

(2) Evaluation of Developer Degradation (Toner Scattering from Developer) After outputting 20000 sheets by the image output method 1, the amount of toner scattering in the machine was visually evaluated based on the following criteria.
A: No toner scattering B: Little toner scattering C: There is a slight toner scattering, and there is a possibility that the image is slightly contaminated after long-term use.
D: There is toner scattering, and the image is contaminated in the second half of image output.
The results are shown in Table 21.

(3) Evaluation of crushing of fine lines After outputting 20000 sheets by image output method 1, fine line images (20 lines, line width 100 μm, interval 300 μm) output individually at each station are fixed by fixing devices 70 and F. An obtained image was obtained. At this time, D cyan, D magenta, yellow, and D black are solid images, and an X-Rite color reflection densitometer (Color reflection density meter).
The development contrast was adjusted and output so that the image density measured with etter X-Rite 404A) was 1.80. The development contrast was adjusted so that the image density of L cyan, L magenta and L black was 1.00.
The resolution of the line was observed using a loupe, and the degree to which the resolution was reduced was confirmed and evaluated. That is, the number of distinguishable lines was evaluated. At this time, the number of lines that can be discriminated was an average value of 10 vertical lines and 10 horizontal lines.
A: 19 or more (very high-definition images)
B: 13-18 (high definition image)
C: 7 to 12 (images with a slight roughness)
D: 6 or less (images with a very rough feel)
The results are shown in Table 22.

(4) Gradation after endurance After the image output method 1 produced 20000 sheets, the image density was determined by measuring each image density with the X-Rite color reflection densitometer.
In this evaluation, evaluation was performed only in the single color mode of cyan (D / L cyan) and magenta (D / L magenta). In the gradation data shown in FIG. 15, the density of the following pattern 8 is gradation data 256 at the right end of the graph.
In the initial setting, each pattern was set to the density shown below, and a shift in gradation before and after outputting 20000 sheets of images was confirmed.
Pattern 1: 0.10-0.15
Pattern 2: 0.25 to 0.30
Pattern 3: 0.45-0.50
Pattern 4: 0.65 to 0.70
Pattern 5: 0.85-0.90
Pattern 6: 1.05-1.10
Pattern 7: 1.25 to 1.30
Pattern 8: 1.40 or more Judgment criteria are as follows.
A: All pattern images satisfy the above density range (smooth gradation and no discomfort compared to the initial image).
B: One pattern image deviates from the above density range (the reflection density measurement value is different from the initial image, but it is not noticed visually).
C: Two pattern images deviate from the above density range (no problem in use).
D: The three pattern images deviate from the above density range (slightly annoying visually compared to the initial image).
E: Four or more pattern images deviate from the above density range (the visual image is uncomfortable compared to the initial image).
The results are shown in Table 21.

(5) Carrier adhesion amount The carrier adhesion level on the initial photoreceptor was judged. This evaluation method is described in Vback. Taping was performed on a solid white drum at 200 V, and the inside of a 5 × 5 cm field of view was observed with a 25 × magnifying glass.
In this evaluation, both the evaluation of single colors of L cyan, L magenta, and L black using the image output method 1 and the full color using the image output method 2 were performed.
A: There is no carrier adhesion at all.
B: Five or less carrier particles are observed.
C: 6 to 10 carrier particles are observed. (Usable level)
D: 11 to 20 carrier particles are observed (the image forming apparatus may be deteriorated).
E: 21 or more carrier particles are observed (the image is uncomfortable and the image forming apparatus deteriorates).
Evaluations for L cyan, L magenta and L black are shown in Tables 8 and 9, and evaluation results for full color output are shown in Table 21.

(6) Density unevenness After outputting 20000 sheets by the image output method 1, a monochrome halftone image (cyan, magenta, black also uses L toner) is printed out, and the vertical streak image density generated on the image is printed out. The number of occurrences of unevenness was visually measured and evaluated.
A: 0 (high definition image quality)
B: One minor vertical image streak occurs (can be used without problems)
C: 2 to 4 (density unevenness is slightly noticeable)
D: 5 or more (density unevenness is conspicuous and very worrisome)
The results are shown in Table 23.

(7) Evaluation of Toner Concentration of Discharge Agent About 1 g of each of the discharge agent and the two-component developer on the developing sleeve after the output of a total of 20000 sheets by the image output method 2 is taken and accurately weighed. A few drops of nonionic surfactant (Contaminon N manufactured by Wako Pure Chemical Industries, Ltd.) and water are added to each of the weighed discharge agent and the two-component developer on the developing sleeve and mixed well. Thereafter, the water from which the toner is eluted is discarded while the carrier is not allowed to flow with a strong magnet.
If the carrier can be washed until the water becomes transparent by repeating the above procedure, drain the water well and dry it in a drying room at 50 ° C. for one day. The mass of the dried carrier is measured, and the toner concentration is determined by the following formula.

The evaluation criteria are as follows.
A: Less than 0% (Deteriorated carriers are discharged very efficiently, and replacement with fresh carriers is performed firmly)
B: 0% or more and less than 0.3%
(Deteriorated carriers are discharged efficiently)
C: 0.3% to less than 0.8% (Slightly fresh carrier and toner are discharged as well as deteriorated carrier, but can be used without any problem)
D: 0.8% or more and less than 1.3% (A lot of undegraded carriers and toners are discharged and consumption increases)
E: 1.3% or more (Undegraded carrier and toner are discharged very much, and replenishment developer is wasted)
The results are shown in Table 24.

(8) Color Variation of Mixed Colors After outputting a total of 20,000 images by the image output method 2, the colors of the mixed colors of green, red, and blue were measured before and after the endurance to confirm the degree of variation.
<Measurement method of color fluctuation difference>
The color variation difference is determined by measuring a ^* and b ^* using SpectroScan Transmission (manufactured by GretagMacbeth). An example of specific measurement conditions is shown below.
(Measurement condition)
Observation light source: D50
Observation field: 2 °
Concentration: DIN NB
White standard: Pap
Filter: None
In general, a ^* and b ^* are values used in the L ^* a ^* b ^* color system, which is a useful means for expressing a color numerically. a ^* and b ^* both represent hue. Hue is a measure of hue such as red, yellow, green, blue, and purple. Each of a ^* and b ^* indicates a color direction, a ^* indicates a red-green direction, and b ^* indicates a yellow-blue direction. In the present invention, the difference in color variation (ΔC) is defined as follows.
[Delta] C = {(endurance initial image a ^* - a ^* of after durability image) ²
+ (Endurance initial image b ^* - Post-durability image b ^{*) 2} 1/2}


In the measurement, arbitrary five points in the image were measured and the average value was obtained. As an evaluation method, a ^* and b ^* of halftone images output at the initial stage of durability and after the end of durability were measured, and ΔC was obtained by the above formula.
A: 0 ≦ ΔC <1.5 (a level that cannot be judged visually)
B: 1.5 ≦ ΔC <3.0 (although it can barely be seen visually, but is not bothered)
C: 3.0 ≦ ΔC <4.5 (usable level)
D: 4.5 ≦ ΔC <6.0 (the color of the image before and after the endurance has changed, and there is a sense of incongruity)
E: 6.0 ≦ ΔC (color variation is conspicuous and there is a sense of incongruity)
The results are shown in Table 25.

<Examples 18 and 19 and Comparative Example 6>
Evaluation was performed using the machine shown in FIG. The developer carrier, the developing tank, the replenisher supply means, and the developer discharge means are as shown in FIGS. Put the two-component developer in the developing unit, put the replenishment developer in the replenisher container, and let it stand overnight at room temperature and normal humidity (23 ° C., 60% RH) so that the toner concentration becomes constant. The image output methods 1 and 2 were evaluated while toner was replenished sequentially. Table 20 shows combinations of the two-component developer and the replenishment developer.
In this evaluation, 30 sheets (A4 size) / min in the monochrome mode of the image output method 1 and 6 sheets (A4 size) / min in the full color mode of the image output method 2, POD super gloss coat manufactured by Oji Paper Co., Ltd. In the full color mode (using L black toner) for photographic image quality using paper, the output speed was 3 sheets (A4 size) / min. The results are shown in Tables 21-24.

In the toner production method of the present invention, the finely pulverized product is classified and surface-modified, and the surface is preferably used in a process for obtaining surface-modified toner particles having a suitable particle size distribution. The schematic sectional drawing of an example of a reformer is shown. (A) shows a schematic horizontal projection plane view of the classification rotor, and (B) shows a schematic cross-sectional view of the classification rotor. (A) shows a horizontal projection plane view of the distributed rotor, and (B) shows a schematic vertical projection plane view of the distributed rotor. (A) shows the figure for demonstrating the diameter of a guide ring, (B) shows the perspective view of the support body of a guide ring and a guide ring. (A) shows a schematic horizontal projection plane view of a square disk, and (B) shows a schematic vertical projection plane view of a square disk. (A) shows a schematic horizontal projection plane view of the liner, and (B) shows a partial explanatory view of the liner. FIG. 3 shows a partial flow chart for explaining a toner manufacturing method of the present invention. 2 is an enlarged model view of a fixing device F portion. FIG. It is the schematic of the parts feeder which measures the transportability index | exponent of this invention. 1 is a schematic diagram of a preferred rotary rotation type image forming apparatus of the present invention. It is a schematic block diagram of a developing device. FIG. 2 is a schematic view of a rotary rotation type developing device. 1 is a schematic view of a preferred image forming apparatus of the present invention. It is a figure which shows the q / d value of a peak top. It is a graph which shows a gradation.

Claims (15)

A first electrostatic image is formed on the first electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component cyan developer. One cyan toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component cyan developer. Forming a second cyan toner image,
The first cyan toner image and the second cyan toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first cyan toner image and a second cyan toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component cyan developer is either a light cyan toner (LC) having a lightness L * in a powder state of 45 <L * ≦ 75 or a dark cyan toner (DC) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component cyan developer contains the other cyan toner and the second carrier,
The first replenishment developer has a lightness L * in a powder state of replenishment light cyan toner (LC) with 45 <L * ≦ 75 or replenishment dark cyan toner (DC) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply cyan toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a transfer index of the replenishment developer containing a replenishment pale cyan toner _(LC) (I LC) and dark cyan toner replenishment _(DC) (I DC) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LC ) <25.0
0.5 <(I _DC ) ≦ 25.0
(I _LC ) <(I _DC )
A first electrostatic image is formed on the electrostatic image bearing member, and the first electrostatic image is developed using a first developer containing a first two-component cyan developer to produce a first cyan image. Forming a toner image,
A second electrostatic image is formed on the electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component cyan developer, and the second electrostatic image is developed. Forming a cyan toner image,
The first cyan toner image and the second cyan toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first cyan toner image and a second cyan toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component cyan developer is either a light cyan toner (LC) having a lightness L * in a powder state of 45 <L * ≦ 75 or a dark cyan toner (DC) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component cyan developer contains the other cyan toner and the second carrier,
The first replenishment developer has a lightness L * in a powder state of replenishment light cyan toner (LC) with 45 <L * ≦ 75 or replenishment dark cyan toner (DC) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply cyan toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a transfer index of the replenishment developer containing a replenishment pale cyan toner _(LC) (I LC) and dark cyan toner replenishment _(DC) (I DC) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LC ) <25.0
0.5 <(I _DC ) ≦ 25.0
(I _LC ) <(I _DC ) The image forming method according to claim 1, wherein the (I _LC ) and (I _DC ) satisfy the following formula.
0 <(I _DC ) − (I _LC ) ≦ 10.0   Carrier / toner mass ratio (C / T (LC)) of the light cyan toner (LC) and the replenishment developer containing the carrier, the replenishment developer containing the dark cyan toner (DC) and the carrier The carrier / toner mass ratio (C / T (DC)) is (C / T (LC)) <(C / T (DC)). The image forming method according to item. A first electrostatic image is formed on the first electrostatic image carrier, and the first electrostatic image is developed using a first developer containing a first two-component magenta developer. One magenta toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component magenta developer. Forming a second magenta toner image,
Transferring the first magenta toner image and the second magenta toner image to a transfer material with or without an intermediate transfer member;
An image forming method for fixing a first magenta toner image and a second magenta toner image on a transfer material by using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component magenta developer is either a light magenta toner (LM) having a lightness L * in the powder state of 45 <L * ≦ 75 or a dark magenta toner (DM) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component magenta developer contains the other magenta toner and the second carrier;
The first replenishment developer is a replenishment light magenta toner (LM) with a lightness L * in the powder state of 45 <L * ≦ 75 or a replenishment dark magenta toner (DM) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply magenta toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light magenta toner transfer index of the replenishment developer containing the _(LM) (I LM) and dark magenta toner replenishment _(DM) (I DM) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LM ) <25.0
0.5 <(I _DM ) ≦ 25.0
(I _LM ) <(I _DM )
A first electrostatic image is formed on the electrostatic image bearing member, and the first electrostatic image is developed using a first developing unit containing a first two-component magenta developer to form a first magenta Forming a toner image,
A second electrostatic charge image is formed on the electrostatic image carrier, and the second electrostatic charge image is developed using a second developer containing a second two-component magenta developer, Forming a magenta toner image,
Transferring the first magenta toner image and the second magenta toner image to a transfer material with or without an intermediate transfer member;
An image forming method for fixing a first magenta toner image and a second magenta toner image on a transfer material by using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component magenta developer is either a light magenta toner (LM) having a lightness L * in the powder state of 45 <L * ≦ 75 or a dark magenta toner (DM) having 20 <L * ≦ 45. Contains one and the first carrier,
The second two-component magenta developer contains the other magenta toner and the second carrier;
The first replenishment developer is a replenishment light magenta toner (LM) with a lightness L * in the powder state of 45 <L * ≦ 75 or a replenishment dark magenta toner (DM) with 20 <L * ≦ 45. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply magenta toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light magenta toner transfer index of the replenishment developer containing the _(LM) (I LM) and dark magenta toner replenishment _(DM) (I DM) is the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LM ) <25.0
0.5 <(I _DM ) ≦ 25.0
(I _LM ) <(I _DM ) The image forming method according to claim 5, wherein (I _LM ) and (I _DM ) satisfy the following formula.
0 <(I _DM ) − (I _LM ) ≦ 10.0   A replenishment developer containing a carrier / toner mass ratio (C / T (LM)), a dark magenta toner (DM) and the carrier of the replenishment developer containing the light magenta toner (LM) and the carrier. The carrier / toner mass ratio (C / T (DM)) is (C / T (LM)) <(C / T (DM)). The image forming method according to item. A first electrostatic charge image is formed on the first electrostatic charge image carrier, and the first electrostatic charge image is developed using a first developer containing a first two-component black developer. One black toner image,
A second electrostatic image is formed on the second electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component black developer. Forming a second black toner image,
The first black toner image and the second black toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first black toner image and a second black toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component black developer is either a light black toner (LK) with a lightness L * in a powder state of 20 <L * ≦ 55 or a dark black toner (DK) of 0 ≦ L * ≦ 20. Contains one and the first carrier,
The second two-component black developer contains the other black toner and the second carrier,
The first replenishment developer is a replenishment light black toner (LK) having a lightness L * in a powder state of 20 <L * ≦ 55 or a replenishment dark black toner (DK) having 0 ≦ L * ≦ 20. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply black toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light black toner _(LK) (I LK) and the transfer index of the replenishment developer containing the deep black toner replenishment _(DK) (I DK) satisfies the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LK ) <25.0
0.5 <(I _DK ) ≦ 25.0
(I _LK ) <(I _DK ) A first electrostatic charge image is formed on the electrostatic charge image carrier, and the first electrostatic charge image is developed using a first developer containing a first two-component black developer to produce a first black Forming a toner image,
A second electrostatic image is formed on the electrostatic image carrier, and the second electrostatic image is developed using a second developer containing a second two-component black developer, Forming a black toner image,
The first black toner image and the second black toner image are transferred to a transfer material with or without an intermediate transfer member,
An image forming method for fixing a first black toner image and a second black toner image on a transfer material using a fixing device to form a fixed image on the transfer material,
The first developing device develops while supplying at least the first replenishment developer containing toner and carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
A configuration in which the second developing device develops while supplying at least a second replenishment developer containing toner and a carrier to the developing device, and discharges at least the excess carrier in the developing device from the developing device. Have
The first replenishment developer and the second replenishment developer contain 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier,
The first two-component black developer is either a light black toner (LK) with a lightness L * in a powder state of 20 <L * ≦ 55 or a dark black toner (DK) of 0 ≦ L * ≦ 20. Contains one and the first carrier,
The second two-component black developer contains the other black toner and the second carrier,
The first replenishment developer is a replenishment light black toner (LK) having a lightness L * in a powder state of 20 <L * ≦ 55 or a replenishment dark black toner (DK) having 0 ≦ L * ≦ 20. Contains either one and the first replenishment carrier,
The second supply developer contains the other supply black toner and the second supply carrier;
The true specific gravity of the first carrier, the second carrier, the first replenishment carrier and the second replenishment carrier is 2.5 to 4.2 g / cm ³ ;
Transfer index of the replenishment developer containing a replenishment light black toner _(LK) (I LK) and the transfer index of the replenishment developer containing the deep black toner replenishment _(DK) (I DK) satisfies the following formula An image forming method characterized by satisfying the above.
0.5 ≦ (I _LK ) <25.0
0.5 <(I _DK ) ≦ 25.0
(I _LK ) <(I _DK ) The image forming method according to claim 9, wherein (I _LK ) and (I _DK ) satisfy the following formula.
0 <(I _DK ) − (I _LK ) ≦ 10.0   Carrier / toner mass ratio (C / T (LK)) of the light black toner (LK) and the replenishment developer containing the carrier, the replenishment developer containing the dark black toner (DK) and the carrier The carrier / toner mass ratio (C / T (DK)) is (C / T (LK)) <(C / T (DK)). The image forming method according to item.   In the powder state of the light black toner (LK) and the dark black toner (DK), the a * value is 0 ≦ a * ≦ 5, and the b * value is 0 ≦ b * ≦ 5. The image forming method according to claim 9.   The carrier is a carrier formed by coating the surface of a carrier core with a coating material, and the coating material contains a coating resin and resin fine particles. The image forming method described. The transfer material has a toner receiving layer on a surface layer, and the fixing device heats and pressurizes the transfer material on which a toner image is transferred, and a first image heating device;
A second image heating device that further heats and pressurizes the transfer material that has passed through the first image heating device;
The second image heating apparatus has an endless belt to which the image surface of the transfer material is in close contact, and forcibly cools the transfer material that remains in close contact with the endless belt after heating and pressurization before separation. The image forming method according to any one of claims 1 to 14.

Images