JP2002304024A - Toner and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce residual toner left after transfer on a photoreceptor to little. SOLUTION: As for the toner used for an image forming apparatus provided with a photoreceptor and an intermediate transfer body whose circumferential speed is different from that of the photoreceptor, and as to the toner measured by a particle analyzing method for guiding the toner particles in a plasma, detecting the emission spectrum, detecting the component amount from the emitted light intensity and then detecting whether the additive agent is synchronized with the toner or isolated from the toner based on the effect whether or not the light is simultaneously emitted, the ratio of the toner with which charging controlling agent is not synchronized is controlled to be <=2%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner to which a charge control agent is added, and an image forming apparatus using the toner.

[0002]

2. Description of the Related Art An electrostatic latent image formed on a photoreceptor is developed with toner, transferred from the photoreceptor to an intermediate transfer member to perform color superposition, and the toner image on the intermediate transfer member is collectively transferred to recording paper. A full-color image forming apparatus is known. The toner used in such an image forming apparatus includes a pigment as a coloring agent, an external additive such as silica and titanium oxide for improving fluidity and chargeability, and a rise in toner charge. And a charge control agent (CCA) for controlling the charge amount and a wax for improving the fixing performance.

[0003]

When developing an electrostatic latent image on a photoreceptor with toner, toner is peeled off from the surface of the developing device by a Coulomb force generated by a developing electric field and adhered onto the photoreceptor. In this case, some of the toners have CCA separated from the surface, and these toners are mixed with the surrounding toner moving to the photoreceptor by the coulomb force due to the developing electric field, and are exposed without the coulomb force being generated. Adhered to the body and developed.

The thus-developed CCA-released toner does not act on the Coulomb force due to the transfer electric field when transferring from the photoreceptor to the intermediate transfer member, and therefore remains on the photoreceptor as transfer residual toner. Probability is high. Although the transfer residual toner needs to be removed by a cleaning unit, it is desired that the transfer residual toner be reduced as much as possible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended to reduce the transfer residual toner on a photoreceptor as much as possible. Accordingly, the invention of claim 1 is directed to a toner used in an image forming apparatus having a photosensitive member having a peripheral speed difference and an intermediate transfer member, wherein toner particles are introduced into plasma to detect an emission spectrum of the toner, and a light emission intensity is detected. The ratio of the charge control agent-asynchronous toner measured by the particle analyzer method that detects whether the additive is synchronized with the toner or is separated from the toner by detecting the component amount and whether the emission timing is simultaneous or not 2% or less. According to a second aspect of the present invention, there is provided a photosensitive member on which at least an electrostatic latent image is formed, a developing unit for developing the electrostatic latent image on the photosensitive member with toner, and a peripheral speed difference between the photosensitive member and the photosensitive member. An intermediate transfer member on which the upper toner image is transferred, and a transfer unit for transferring the toner image on the intermediate transfer member onto paper, wherein the toner is the toner according to claim 1.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining the transfer efficiency of toner used in the image forming apparatus of the present invention.
The asynchronous ratio and the vertical axis indicate the transfer efficiency. First, CCA
The asynchronous rate will be described.

In recent years, toner particles have been analyzed by a particle analyzer method. In the particle analyzer method, toner particles are introduced into plasma to excite and emit light. The toner particles are obtained by adding an external additive such as silica or a charge control agent (CCA) such as a metal-azo complex to base particles made of a resin (carbon) such as polyester. An emission spectrum (frequency) peculiar to the above and an emission intensity corresponding to the amount of the element are obtained. Therefore, the emission frequency and its intensity are measured, the amounts of the base particles and CCA are respectively measured from the measurement results, and the amounts of the base particles and CCA are converted into true spherical particles and expressed in terms of particle diameter, and the equivalent particle diameter is obtained. It is obtained as the cube root voltage of the signal intensity (proportional to mass) of the measured emission spectrum (see Japanese Patent Application Laid-Open No. 12-47425).

Further, in the particle analyzer method, when the toner base particles and the additive are integrated, the light emission is detected at the same timing, so that they are synchronized (synchronous toner).
When the toner base particles and additives are free,
Since the light emission is detected at different timings, it is called asynchronous (asynchronous toner). The asynchronous ratio in FIG. 1 indicates the ratio of the asynchronous toner in which CCA is released from the base particles.

According to the present invention, when the transfer residual toner on the photoreceptor is analyzed in various ways by the particle analyzer method, it is noted that the ratio of the toner whose CCA is not synchronized is large, and the relationship between the CCA asynchronous ratio and the transfer efficiency is determined. It was found and reached.

In the experiments leading to the present invention, as shown in Table 1, three types of CCA were selected as zinc salicylate, chromium salicylate, and a combination of zinc salicylate and chromium salicylate. 0.97%, 2.5%, 3.8%, and for chromium salicylate, the asynchronous rate was 0.68%, 2.2%, 2.9.
%, The asynchronous rate is 0.42%,
Nine types of toners were prepared at 1.3% and 1.7%.

[0011]

[Table 1] Table 2 shows the measurement results of the transfer efficiency when a predetermined speed difference (peripheral speed difference) was applied between the photosensitive member and the intermediate transfer belt for the toners having the nine asynchronous rates. In Table 2, the speed difference is (+) when the intermediate transfer belt is fast, and (-) when the photoconductor is fast, and is -1.4%, +0.8.
%, + 1.4%, + 3%, and + 5%. The transfer efficiency is measured by stopping the engine in the process of performing all solid printing (printing of the entire image), and measuring the toner amount M1 on the photoconductor before the primary transfer and the toner amount on the intermediate transfer belt after the transfer. M2 was measured and calculated as M2 / M1.

[0012]

[Table 2] FIG. 1 is a graph of the results in Table 2. In FIG. 1, the characteristics A, B, C, D, and E each have a speed difference of 5
%, 3%, 1.4%, -1.4%, and 0.8%. From FIG. 1, it can be seen that the larger the speed difference, the better the transfer efficiency, and the smaller the CCA asynchronous ratio, that is, the less the asynchronous toner, the better the transfer efficiency. In the characteristics A and B where the speed difference is large, the transfer efficiency is maintained satisfactorily until the CCA asynchronous ratio is slightly larger than 2%. In the case of the characteristics C, D and E where the speed difference is small, the CCA asynchronous ratio is 2 or less.
%, The transfer efficiency is well maintained. As described above, it is preferable that the CCA asynchronous rate is small. However, when the CCA asynchronous rate is approximately 2% or less, it can be seen that good transfer efficiency is maintained within the range of the normally used speed difference. Examining this in the transfer process, CCA asynchronous toner is mixed with CCA synchronous toner and developed on the photoconductor. However, the transfer efficiency also depends on the speed difference. When transferring from to the intermediate transfer belt, not only the Coulomb force,
It is considered that the toner on the photoreceptor is peeled off by the mechanical force and the transfer is performed. it is conceivable that. Incidentally, if the speed difference between the photosensitive member and the intermediate transfer belt is too large, the image is disturbed, which is not preferable. Comparing the characteristics C and D, it can be seen that if the absolute value of the speed difference is the same, almost the same transfer efficiency can be obtained irrespective of whether the photosensitive member or the intermediate transfer belt is faster. The transfer from the intermediate transfer belt to the paper has a small speed difference because the toner adheres to the paper, and the transfer efficiency is good even if there is no speed difference.

Next, CCA (Charge Controller)
ol Agent). The charge amount required for the toner must be an appropriate charge amount. It is instantaneously charged by friction with the charging member and is stable over time. The change in charge amount due to temperature and humidity is small. And the like. It is also important that the toner does not thermally decompose when kneading the toner or by heating during fixing.

From the above viewpoints, compounds having the chemical structures shown in Chemical Formulas 1 and 2 are currently used as charge control agents. Chemical formula 1 is a typical negative charge control agent, and chemical formula 2 is a typical positive charge control agent.

[0015]

Embedded image

[0016]

Embedded image FIG. 2 is a diagram illustrating the configuration of a tandem image forming apparatus using the toner of the present invention. The exposure device 20 is Y, C,
The laser light modulated by the M and K images is applied to the image forming unit 30.
(Y), 30 (C), 30 (M), and 30 (K) are irradiated. In each of the Y, C, M, and K image forming sections, after the photosensitive member 31 is uniformly charged by the charging device 32, an electrostatic latent image is formed by the laser beam from the exposure device 20, and the electrostatic latent image is developed by the developing roller 33. The intermediate transfer belt 38 is pressed between the photoreceptor 31 and the primary transfer roller 34 so that the intermediate transfer belt 38
Next is transferred. The residual toner on the photoconductor after the transfer is removed by a cleaning blade 35. Thus, each of the image forming units 30 (Y), 30 (C), 30 (M), 30 (K)
The toner images formed on the photoreceptor are sequentially transferred and color-superimposed on an intermediate transfer belt 38 which is driven by a drive roller 36 with a peripheral speed difference between the backup roller 37 and the photoreceptor. On the other hand, the recording paper is sent from the paper tray 40 to the paper transport path P by the paper feeding device 41, and is sent to the secondary transfer unit by the supply roller 42. The secondary transfer section is formed by the backup roller 37 and the secondary transfer roller 43, and the four color toner images on the intermediate transfer belt 38 are transferred onto paper and fixed by the fixing device 44. The toner remaining on the intermediate transfer belt after the secondary transfer is the cleaning blade 3
9 is cleaned. As described above, in the toner used in this image forming apparatus, since the ratio of the toner whose charge control agent is asynchronous is 2% or less, the toner is transferred from the photoconductor to the intermediate transfer belt with high transfer efficiency. In the transfer, the toner is efficiently adhered to the paper, so that the transfer is efficient.

[0017]

As described above, according to the present invention, CCA
By setting the ratio of the asynchronous toner to 2% or less, it is possible to maintain good transfer efficiency and extremely reduce transfer residual toner on the photoconductor.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the relationship between the transfer efficiency and the asynchronous ratio of the toner of the present invention.

FIG. 2 is a diagram illustrating a configuration of a tandem image forming apparatus using the toner of the present invention.

[Explanation of symbols]

20 exposure apparatus, 30 (Y), 30 (C), 30
(M), 30 (K): image forming unit, 31: photoconductor, 32
... Charging device, 33 ... Developing roller, 34 ... Primary transfer roller, 35 ... Cleaning blade, 36 ... Drive roller
37 backup roller, 38 intermediate transfer belt, 3
9 cleaning blade, 40 paper tray, 41
Paper feeding device, 42: supply roller, 43: secondary transfer roller, 44: fixing device.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G043 AA01 CA06 DA05 EA06 LA01 2H005 CA25 DA02 EA10 2H200 FA20 GA12 GA23 GA29 GA44 GA47 HA02 HB12 HB22 JA02 JC03 JC19 PA11

Claims (2)

[Claims] In a toner used in an image forming apparatus having a photosensitive member having a peripheral speed difference and an intermediate transfer member, toner particles are introduced into plasma to detect an emission spectrum thereof, and a component amount is detected from emission intensity. However, depending on whether the light emission timing is simultaneous or not, the ratio of the charge control agent-asynchronous toner measured by the particle analyzer method for detecting whether the additive is synchronized with the toner or separated from the toner is 2% or less. A toner characterized in that: 2. A photoreceptor on which at least an electrostatic latent image is formed, a developing unit for developing the electrostatic latent image on the photoreceptor with toner,
2. An image forming apparatus according to claim 1, further comprising: an intermediate transfer member having a peripheral speed difference with respect to the photosensitive member, to which a toner image on the photosensitive member is transferred, and a transfer unit for transferring the toner image on the intermediate transfer member onto paper. An image forming apparatus comprising the toner described in claim 1.