JP2009025191A - Method and system for evaluating toner scattering properties - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating the toner scattering properties in a gaseous phase reflecting the actual behavior of toner particles in an actual machine, and to provide a system for evaluating the toner scattering properties. <P>SOLUTION: A toner scattering device constituted so as to be matched with an actual toner scattering model case is used as a source to scatter toner particles and the air flow containing the scattered toner particles is introduced into a separation part (e.g., Andersen sampler) constituted of a combination of a nozzle 1 and a collision plate 2 by dry gas (e.g., air) dynamical force and ejected from the nozzle 1 to separate and classify the toner particles in the air flow into a particle group with low scattering properties and a particle group with high scattering properties in a plurality of the separation parts arranged to a separator. The content of the classified particulates with a predetermined size is calculated to evaluate the scattering degree of toner. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner scattering property evaluation method and an evaluation system thereof, and more particularly to toner scattering and image inside a copying machine from evaluation of toner scattering property reflecting the actual behavior of a toner particle group in a gas phase in an actual machine. The present invention relates to a toner scattering property evaluation method and an evaluation system that can determine background stains in formation.

Conventionally, various proposals regarding the particle size and shape of toner particles have been made as approaches for realizing high image quality in the electrophotographic field.
For example, Patent Document 1 [0021] discloses an electrostatic charge image developing toner that can form a black or full color image with high image quality and high reliability without toner scattering by removing fine powder in the toner. It describes that it can be manufactured, and shows the influence of the amount of fine powder in the toner on the scattering property of the toner.

As a toner particle size evaluation method, for example, Coulter Multisizer is known as an electric resistance particle size distribution measuring device that detects the volume of toner particles dispersed in a liquid and outputs a spherical equivalent diameter from the volume. (For example, see Patent Document 2 [0038].)
However, according to Patent Document 2 [0003], with regard to toner scattering properties and background stains, it is necessary to further evaluate the shape of the particles. For example, an irregularly shaped toner causes scattering and background stains even in a small amount. It is described that it becomes.

  As described above, a value measured by an electric resistance type Coulter multisizer or the like is widely used as the particle diameter of the toner. However, the value measured by the Coulter Multisizer is a sphere equivalent diameter converted from the volume of particles measured in the liquid phase, so-called gas dynamics important for knowing the behavior in the gas phase, In particular, it does not take into account aerodynamic characteristics.

In addition, a particle size distribution measuring device in a liquid phase including a Coulter multisizer is measured by dispersing as many primary particles as possible in order to measure the particle size accurately. However, in the dry electrophotographic process, since the toner is handled in the gas phase (so-called handling), it is necessary to evaluate the aerodynamic characteristics of the particles.
For example, even if the toner has a spherical equivalent diameter of 5 μm, the aspherical toner and the flat toner have different aerodynamic characteristics, and the flat toner has the aerodynamic characteristics similar to those of smaller spherical particles. Even in the same shape, particles made of a material with a low specific gravity have characteristics as finer particles.

  Another problem is the difference between the dispersibility in the gas phase and the dispersibility of the toner particles in the liquid phase. In Coulter Multisizer, etc., the particle size of particles dispersed forcibly with ultrasonic waves or the like is measured using a surfactant in the liquid phase. However, it is clear that the scattering property of the toner handled in the gas phase is different from the dispersibility in the liquid phase.

There is also a problem of external additives in the toner. In the toner, in order to adjust various physical properties required in actual printing, an external additive such as silica fine particles is added to the toner base. It is known that the addition of such an external additive changes the powder properties such as fluidity, dispersibility, and scattering properties of various powders including the toner base. However, in the method such as the Coulter Multisizer, the influence of the external additive is not considered.
Moreover, it is known that the change in the powder physical properties due to the external additive also changes depending on, for example, the humidity. Conventionally, these problems have not been sufficiently considered.

Further, a toner having a charging problem is generally used for printing utilizing its charging property, and this charging property has a great influence on the scattering property and fluidity of particles. However, in the method such as the Coulter Multisizer, the influence of charging is still not taken into consideration.
Similarly, problems with external additives, chargeability, and humidity can affect the transfer and development process of other toners, for example, the adhesion force including the electrical transfer with the intermediate transfer belt and the photoreceptor, and the scattering state. give.

  That is, in order to evaluate the properties of the toner, the behavior of the toner particle group in the gas phase must be considered, but there is a problem with the conventional method.

JP 2007-93669 A JP 2007-94358 A

As described above, Coulter Multisizer and the like are applied for the evaluation of the properties of conventional toners, particularly the shape of toner particles, but under these evaluation conditions, ultrasonic waves or the like are used in the liquid phase using a surfactant. There has been a problem that the particle size of the forcibly dispersed particles is measured, and the influence of the external additive and chargeability of the toner is not taken into consideration.
The present invention has been made in view of the above prior art, and is a toner scattering property evaluation method reflecting the actual behavior of the toner particle group in the gas phase in an actual machine, that is, the shape of the toner and its specific gravity, To provide a gas dynamic (particularly aerodynamic) characteristic that comprehensively considers external additives and charging characteristics of a toner, a so-called toner scattering evaluation method in a gas phase and a toner scattering evaluation system. It is another object of the present invention to evaluate the level of toner scattering by the toner scattering property evaluation method and the toner scattering property evaluation system, and to prevent toner scattering inside the copying machine and background stains in image formation.

  As a result of intensive studies, the present inventors have determined that the toner scattered from a toner scattering device configured according to an actual toner scattering model case can be separated into a plurality of separation units by dry and aerodynamic, in particular aerodynamic forces. Can be properly evaluated in the gas phase by separating and classifying the particles into a particle group having a low scattering property and a particle group having a high scattering property. And the present invention has been found to solve the above problems. Hereinafter, the present invention will be specifically described.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [12], and have reached the present invention. Hereinafter, the present invention will be specifically described.

  [1]: The above problem is that the air flow including the scattered toner particles generated by the toner scattering device is introduced into the separation device by a dry and aerodynamic force, and the plurality of separation units provided in the separation device Separating and classifying toner particles in the air stream into low-scattering particle groups and high-scattering particle groups, and determining the fine powder content of the classified predetermined size to evaluate the level of toner scattering This is solved by a toner scattering property evaluation method characterized by the above.

  [2]: In the toner scattering property evaluation method according to [1], the airflow is an airflow.

  [3]: In the toner scattering property evaluation method described in [1] or [2] above, the toner is composed of a single toner base containing at least a binder resin and a colorant, or the toner base and an external additive. It is one of the structures which consist of an agent.

  According to the above [1] to [3], the actual condition of the toner particle group in the gas phase is similar to the actual machine environment in which the shape of the toner and its specific gravity, the external additive and the charging characteristics of the toner are comprehensively taken into account. It is possible to evaluate the scattering property of the toner reflecting the behavior. From the high and low evaluation of the toner scattering property equivalent to the actual environment, it is possible to avoid the toner scattering inside the copying machine and the background stain at the time of image formation, and it is possible to form an image with high image quality and high reliability. Further, contamination inside the copying machine and the like is prevented.

  [4]: In the toner scattering property evaluation method according to any one of [1] to [3], the toner to be evaluated is scattered from a two-component developer mixed with a carrier. Features.

  As described above, even in the toner using the two-component developer, the scattering property reflecting the actual behavior considering the interaction with the carrier can be evaluated.

  [5]: In the toner scattering property evaluation method according to any one of [1] to [4], the separating device uses an inertial collision method to separate toner particles into particles having low scattering properties and particles having high scattering properties. It is characterized by being separated and classified into groups.

  By the inertial collision method, the particle group with low scattering property and the particle group with high scattering property are reliably separated and classified, and the fine powder content of the scattering toner particles can be measured suitably.

  [6]: The toner scattering property evaluation method according to any one of [1] to [5], wherein the toner scattering device includes a toner agitation unit, and the agitation unit generates scattered toner in the airflow. It is characterized by being.

  With the toner scattering device configured as the model case, for example, the actual toner scattering property at the time of stirring in the toner container can be evaluated.

  [7]: In the toner scattering property evaluation method according to any one of [1] to [5], the toner scattering device includes a fluidizing unit for particles, and the fluid group includes a particle group including a toner base. It is characterized in that it is fluidized to generate scattered toner in an air stream.

  With the toner scattering device configured as the model case, for example, the actual toner scattering property when the toner in the copying machine or the printer is transported and conveyed from the toner container to another toner container can be evaluated.

  [8] In the toner scattering property evaluation method according to any one of [1] to [5], the toner scattering device includes a magnetic generation unit, and the carrier is held by the magnetic force of the magnetic generation unit. The toner present together with the held carrier is blown by an air flow to generate scattered toner in the air flow.

  With the toner scattering device configured as the model case, the toner scattering property can be evaluated in a scattering state in consideration of the influence of adhesion force including electrostatic force between the toner and the carrier. That is, it is possible to evaluate the actual toner scattering property that is scattered in a charged state closer to the charged state in the copying machine or printer.

  [9]: The toner scattering property evaluation method according to any one of [1] to [8], wherein an air flow including the scattering toner particles is conditioned.

  By controlling the airflow, the toner scattering property against humidity fluctuations in the actual environment can be evaluated.

  [10]: In the toner scattering property evaluation method according to any one of [1] to [9], the separation device introduces a suction air flow including scattered toner particles from a nozzle by a suction unit, and collides with an ejection air flow. A cascade impactor comprising a plurality of impactor units that collide with a plate, and configured to collect a particle group having a low scattering property and a particle group having a high scattering property separated and classified in each impactor unit. .

  By using a cascade impactor configuration for the separation device, the scattered toner particles are separated into a low-scattering particle group and a highly-scattering particle group by aerodynamic force, and the toner particle size distribution is measured at once. Therefore, it is extremely suitable as a so-called toner scattering evaluation apparatus.

  [11]: In the toner scattering property evaluation method according to [10], the separation device introduces a predetermined suction air flow including scattering toner particles by a suction unit, and particles having low scattering property by a plurality of impactor units. An under-sensor sampler configured to be separated and classified into a group and a highly scattering particle group, and the suction air flow is set to 28.3 L / min.

  It is a device configuration suitable as a toner scattering evaluation device and air flow rate conditions at the time of measurement, and this makes it possible to evaluate the level of toner scattering reflecting the actual behavior of toner particles in the gas phase in an actual machine. . In particular, a standard apparatus used for environmental dust evaluation and the like can be used, which is preferable from the viewpoint of compatibility.

[12]: The above problem is a toner scattering device that generates scattered toner in an air stream;
Separation provided with a plurality of separation parts for separating and classifying into a group of particles having low scatterability and a group of particles having high scatter property by introducing an air flow including scattered toner generated by the toner scatter device by dry and aerodynamic force Consisting of equipment,
This is solved by a toner scattering property evaluation system configured to evaluate the level of toner scattering property from the classified fine powder content of a predetermined size.

According to the toner scattering property evaluation method of the present invention, toner scattered from a toner scattering device configured in accordance with an actual toner scattering model case is introduced into a separation device having a plurality of separation units, and scattered. This is a method that separates and classifies the particle group into a particle group with low scattering properties and a particle group with high scattering properties, so that the behavior of the toner particle groups actually acting in the gas phase in the actual use environment can be reflected and the toner scattering property can be reflected. Can be evaluated appropriately. Based on this evaluation, it is possible to comprehensively take into account the shape of the toner, the specific gravity of the toner material, or the external additive and charging characteristics of the toner. Thus, it is possible to take measures to prevent or avoid toner scattering and background stains in image formation.
According to the toner scattering property evaluation system of the present invention, the toner shape, the specific gravity of the toner material, or the external additive and charging characteristics of the toner are comprehensively taken into consideration in accordance with an actual toner scattering model case. It is possible to evaluate the toner scattering property reflecting the actual behavior of the toner particle group in the gas phase as the use environment.

  As described above, in the toner scattering property evaluation method according to the present invention, an air flow including scattered toner particles generated by the toner scattering device is introduced into the separation device by dry and aerodynamic force, and is provided in the separation device. The toner particles in the air stream are separated and classified into a group of particles having low scattering properties and a group of particles having high scattering properties by a plurality of separation units, and the fine powder content of the classified predetermined size is obtained. It is characterized by evaluating the height of.

The best mode for carrying out the present invention will be described below with reference to the drawings.
In the first embodiment of the toner scattering property evaluation method of the present invention, the toner particles are dispersed in the gas phase (dry type) by aerodynamic force and introduced into the separation device. It is to separate and classify into highly functional particle groups, and to evaluate the fine powder content of toner of a predetermined size. Here, if the air flow is an air flow, the actual printing environment can be reflected. For example, air that comprehensively takes into account the shape of the toner, the specific gravity of the material, the external additive and charging characteristics of the toner, and the like. The scattering property of the toner in the gas phase can be evaluated based on the mechanical characteristics. As a specific method of classification by aerodynamic force, an air flow and a separation force are used. As the separation force, an inertial force, a centrifugal force, an electric field, or the like can be used.
The toner may be composed of a toner base alone containing at least a binder resin and a colorant, or a structure composed of the toner base and an external additive.

In the second embodiment of the toner scattering property evaluation method of the present invention, toner particles are separated and classified into a particle group having a low scattering property and a particle group having a high scattering property by an inertial collision method using a separation device. . That is, the toner particles in the air stream are classified in a dry manner by a plurality of separation units provided in advance in the separation device, and the classified fine powder content is determined to evaluate the level of toner scattering.
For example, the schematic diagram of FIG. 1 schematically shows a cross section of a main part of a separation device that separates and classifies toner particles by an inertial collision method. A plurality of separation units having a configuration in which the nozzle and the collision plate shown in the cross-sectional view of the main part of FIG. 1 are combined are provided, and in each separation unit, a particle group having a low scattering property and a particle group having a high scattering property are sequentially provided according to the size of toner particles By collecting the toner particles, the scattered toner particles are reliably separated and classified, and the fine powder content can be suitably measured.
As shown in FIG. 1, an air flow (in this case, air sucked by a pump or the like) containing scattered toner particles generated by a toner scattering device (not shown) is ejected from the nozzle 1 in the vertical direction, and the ejected fluid is abruptly Although the direction is changed, among the toner particles that have been on the fluid streamline until now, the particles with large inertia cannot move on the streamline, move in the vertical direction as they are, collide with the collision plate 2 and adhere to the collision plate. Will be collected. On the other hand, the particles with small inertia escape the collision and are sequentially discharged together with the air current to a separation unit of a similar mechanism (not shown). This is a kind of classification mechanism. The larger the airflow jet velocity from the nozzle, the smaller the nozzle diameter d, and the shorter the distance L (3) from the nozzle tip to the collision plate, the smaller the collision plate. Will be collected, and the classification diameter will be small.

Here, the measurement by the inertial collision method will be described. If the streamline radius of the airflow bending in front of the impingement plate 2 is R, the inertial force F of the particle of mass m and velocity v is:
F = mv ² / R
It is represented by In laminar flow, from the Stokes equation,
F = 3πDηU _t
It is. Here, U _t is the tangential velocity, η is the viscosity of air, and D is the particle diameter.

The distance L over which the particles move in the time t required for the air flow to flow through the streamline of πR / 2 at the velocity U is, if the buoyancy of the particles is ignored
L = U _t t = πρD ² U / 36η
It is.
That is, if L is half the width of the flow, the minimum particle diameter based on the aerodynamic diameter that can be effectively separated is obtained by the following equation.
D _min = √ (36 Lη / πρU)

  Examples of the separation device that separates particles based on the principle as described above (hereinafter sometimes referred to as “measuring device” or “measuring device” or “measuring means”) include, for example, a cascade impactor, particularly an under-sensing sampler. And so-called twin impinger are preferable, and an under-sensor sampler is particularly preferable.

Here, a more specific example of a separation device (measuring instrument) for classifying toner particles by an inertial collision method suitable for the implementation of the present invention will be described.
The schematic diagram of FIG. 2 shows a configuration of a measuring device generally called a twin impinger that is suitable as a separating device for separating and classifying toner particles by the inertial collision method. A twin impinger with such a configuration is a device that has been certified as Apparatus A (EP Chapter 2.9.18) to correlate with the aerodynamic diameter of the particles of the inhalation formulation.
A twin impinger 41 shown in FIG. 2 schematically includes a mouthpiece adapter (connection portion with a toner scattering device not shown) 42, a throat 43, a neck 44, an upper collision chamber 45, a coupling tube 46, an inlet 47, It consists of a lower jet collecting part 48, a lower collision chamber 49, and a pump (not shown). The twin impinger 41 is sucked from the suction port 47 by a pump (not shown). Then, the toner particle dust scattered from the mouthpiece adapter 42 is sucked from a construction model (toner scattering device configured according to the actual toner scattering model case) configured according to a toner scattering model case determined separately. To do.

  Specifically, by connecting a toner scattering model device (toner scattering device), which is a generation source of scattered toner, to a twin-pinger and sucking, the total amount of toner reaching stage 1 and stage 2 is expressed as α. .Beta. And .gamma. =. Alpha. +. Beta., The toner having the smaller .beta. Is most difficult to scatter, and the toner having the smaller .alpha. Is more difficult to scatter. In addition, toner with smaller γ is more difficult to be scattered.

  In this case, the suction flow rate from the suction port 47 is preferably 60 L / min. By sucking the gas in the twin impinger 41 from the suction port 47, the mouthpiece adapter 42, the throat 43, the neck 44, the upper collision chamber 45, the coupling tube 46, the suction port 47, the lower jet collection part 48, the lower part The toner particles move on the airflow in the order of the collision chamber 49. The particles deposited in the stage 2 region are determined to be a highly scattering particle group. That is, the toner having a small weight ratio of the particles reaching the stage 2 has a low scattering property, and is determined to be a toner that hardly causes the toner scattering and the background contamination inside the copying machine.

The third embodiment is to measure the toner scattering property of a two-component developer in which toner and carrier are mixed. The mixing means of the toner and the carrier may be a mixing method disclosed in the related art, or may be a mixing method used when the toner is actually commercialized. In other words, the scattering model configuration in which the toner accommodated and scattered in the toner scattering device is derived from the two-component developer makes it possible to evaluate the scattering property reflecting the actual behavior considering the interaction between the toner and the carrier.
As the carrier to be mixed with the toner, it is preferable to use a carrier used when making a product unless there is a particular limitation. However, when measuring a one-component developer, a carrier may be selected separately.

  Specifically, at the time of mixing, the toner and the carrier are mixed so as to have an appropriate mixing amount (the toner is 2 to 15% by mass), and are mixed, for example, for 180 seconds with a tumbler mixer. At this time, in the case of toner for one-component developer, TEFV (manufactured by Powder Tech Co., Ltd.) or a standard carrier provided by the Imaging Society of Japan can be used as a so-called standard carrier.

  The mixing time of the toner and the carrier may be arbitrary depending on the purpose of the measurement. For example, when it is desired to observe the state immediately after the mixing of the toner and the carrier, it is preferably 15 seconds to 5 minutes, more preferably 15 seconds to 1 minute. is there. When it is desired to observe a state where the toner and the carrier are sufficiently mixed, 5 minutes to 30 minutes is preferable. When it is desired to observe the state of the deteriorated toner, mixing may be performed for a longer time.

The schematic diagram of FIG. 3 shows an example in which the toner in the two-component developer contained in the toner scattering device is introduced into the separation device by suction.
The mixed powder of the toner and the carrier is put into a toner scattering device 30 formed of a metal container having a pair of conductive screens (mesh portions) 31 having a mesh structure, and sprayed (blow) from one side. Then, the sample is sucked into a separation device (measuring means) (not shown), or a metal container is placed in a measuring device and sucked.
The conductive screen (mesh portion) 31 has a mesh structure with a mesh size (for example, 635 mesh) that does not allow the carrier to pass but allows the toner to pass.

  Hereinafter, FIG. 3 will be described. In FIG. 3, the opening diameter of the mesh portion 31 is larger than the diameter of the toner and smaller than the diameter of the carrier. Then, a toner / carrier mixture (developer) 32 is accommodated in the container and the mesh portion is sucked from the outside, or as shown in the schematic view of FIG. More preferably, the toner in the component developer is blown by an air nozzle and introduced into the separation device. In FIG. 4, a mixture of toner and carrier (developer) 22 is obtained by blowing (blowing) gas (mainly air) with an air nozzle 23 so as to scan the entire conductive screen (mesh portion) 21 having a mesh structure. Are physically separated with stirring. Thereby, only the separated toner smaller than the opening of the mesh portion 21 passes through the opening of the mesh and is blown off to the outside, and is guided to the separating device (measuring means). At this time, since the toner is blown off while being charged, it is possible to evaluate the scattering property of the toner in a state closer to that used in a copying machine or a printer as a model case. The schematic diagram of FIG. 5 shows an enlarged view of the scattering state of the toner and the carrier constituting the two-component developer of FIG. In FIG. 5, reference numeral 24 denotes a carrier, and 25 denotes toner.

In the fourth embodiment, the toner scattering device includes a toner agitation unit, and the measurement is performed while the toner is agitated. Thus, the agitation property due to agitation can be evaluated. This agitation may be according to a conventional method such as a model of agitation mechanism inside the copying machine or agitation in the production process. These configurations are shown in the schematic diagrams of FIGS.
FIG. 6 is a schematic diagram showing a configuration example of a toner scattering device that generates scattered toner in the airflow by the stirring blade 64, and FIG. 7 is a toner scattering device that generates scattered toner in the airflow by the stirring roller 64R with the stirring blade 64F. It is the schematic which shows the example of a structure.

The agitation blade 64 (FIG. 6) and the agitation roll 64R with the agitation blade 64F (FIG. 7) respectively physically disperse the toner or the toner-carrier mixture (developer) 66 while stirring.
That is, toner or a mixture of toner and carrier (developer) is stored in a container of the separation device, and the toner is physically scattered while air is circulated from the outside. The toner scattered by the agitation is conveyed by the air flow 65 and guided to the separation device (measurement means). In particular, if a configuration using a stirring roll or a stirring blade used in a copying machine or printer is used, the evaluation can be made based on the scattering characteristics of toner scattered from the copying machine or printer.

In the fifth embodiment, the toner scattering device is provided with a particle fluidizing means, whereby the toner particles are dispersed while being fluidized, and introduced into a separating device (measuring means) to measure the toner scattering property. It is possible to evaluate the toner scattering property when the toner in the copying machine or printer is transported or transported from the toner container to another toner container.
For example, a member that can circulate air while holding toner particles (toner powder), such as a metal sintered filter or a punching plate, is installed at the bottom of the toner powder container of the toner scattering device. In addition, the toner powder can be fluidized by circulating air from the lower part to the toner powder container.
The direction in which air is circulated (the direction of the air flow) preferably has an upward vector in the vertical direction with respect to the powder layer in the toner powder container. The magnitude of the upward vector in the vertical direction of the airflow velocity when fluidizing the toner powder is preferably 0.05 to 1.0 m / s, more preferably 0.1 to 0.7 m / s, and still more preferably. Is 0.2 to 0.6 m / s.
Note that a member that can circulate air and has directionality to the outflow of air is installed at the bottom of the toner powder container. Such a member is not limited, but for example, as shown in the schematic diagram of FIG. 14A, if the flow member 6 is formed with a slit-like opening 5 with an opening shape inclined, When the flow 7 passes through the flow member 6 with directionality and is a swirl type flow member 6 as shown in the top view of FIG. 14B, air can swirl and flow in the flow member 6.
That is, to circulate air having an upward vector in the vertical direction with respect to the powder layer in the toner powder container describes the air flow after passing through the flow member.

A specific method is shown in the schematic diagram of FIG. FIG. 8 shows a configuration example of a toner scattering device that generates a scattered toner in an air flow by fluidizing a particle group including a toner base by a fluidizing unit.
The apparatus shown in FIG. 8 accommodates toner powder 72 in a toner powder container 71 of a toner scattering apparatus 70, and air is sucked from outside through a mesh member 73 that can be vented to scatter toner. The example of a structure for making it guide to a separation apparatus (measurement means) is shown. A material such as a mesh member that does not leak toner powder downward is used. Specifically, a breathable cloth, felt, sintered filter or the like is preferable.

In the sixth embodiment, the toner scattering device includes a magnetism generating unit, and while holding the carrier by the magnetic force of the magnetism generating unit, the toner existing with the held carrier is sprayed by an air flow to scatter the toner and separate it. It is introduced into an apparatus (measuring means) to evaluate toner scattering properties.
This makes it possible to evaluate the scattering performance of the toner in consideration of the influence of the adhesive force including the electrostatic force between the toner and the carrier, and the scattering performance of the toner scattered in a charged state closer to the charged state inside the copying machine or printer. Can be evaluated. In other words, by holding the carrier with a magnetic force and blowing the toner while blowing the toner present together with the carrier with an air flow, the scattering property of the toner particles can be evaluated in a state in which the carrier is prevented from being scattered when blown. .
The schematic diagram of FIG. 9 shows a configuration example of a toner scattering device that generates toner scattered in an air flow by blowing toner existing with a carrier by an air flow.
For example, a magnetic brush is formed on a magnetic roll 93 having a magnet inside, and a blown air flow 96 blown from a nozzle-like device, that is, an air supply means 95 is collided with the magnetic brush to separate and scatter toner. Then, an air flow containing toner is sucked into the separation device (measurement means).

Referring further to FIG. 9, one or more stirring rolls 92 are provided in a mixing container 91 for storing a mixture of toner and carrier as required. Carrier particles and toner adhering to the carrier particles are pumped up from the inside of the mixing container by the magnetic roll 93, and the adhering amount is adjusted by a regulating means 94 such as a doctor blade installed as necessary, and then air is supplied. The toner particles blown by the air flow from the means 95 and separated from the carrier by the blow air flow 96 ejected from the air nozzle 97 are guided to a separation device (measurement means).
FIG. 10 is a schematic view schematically showing the state of the magnetic brush formed on the magnetic roll in FIG. FIG. 11 is an enlarged view schematically showing, as an example, the case of the two-component developer composed of toner and carrier in FIG.

In the seventh embodiment, the airflow for separating and classifying the scattered toner particles is conditioned, and for example, the airflow is conditioned when the particle diameter of the toner is measured by a dry inertial collision method. It relates to the thing which reproduces the scattering property in the specific environment. By adjusting the airflow, the scattering property of the toner with respect to the humidity can be evaluated.
As humidity control conditions, the temperature may be adjusted, and the temperature is preferably 0 to 45 ° C, more preferably 5 to 40 ° C, and still more preferably 8 ° C to 35 ° C.
The humidity range is preferably 10 to 100 RH%, more preferably 13 to 98 RH%, and still more preferably 15 to 93 RH%. Moreover, in order to compare each measurement or evaluation result, it is good to make humidity into the same conditions in each measurement. Further, it is desirable that the humidity of the atmosphere including the suction unit, the toner scattering device, and the separation unit is adjusted not only from the air flow but also from the toner storage environment.

  In the eighth embodiment, an impactor unit is configured such that a separation device introduces a suction airflow containing scattered toner particles from a nozzle by a suction means, and collides the ejected airflow with a collision plate to collect the scattered toner particles. This is due to the cascade impactor provided with a plurality of. In other words, a cascade impactor is a device that combines multiple stages of units that classify and collect the required particle size particles using streamlines created by airflow passing through a plate having a hole of a fixed size. It is an apparatus that sequentially collects particles having a large aerodynamic diameter from a unit located upstream of an air flow to a unit located downstream. As a result, the scattered toner particles can be separated and classified according to the level of scattering properties by aerodynamic force, and the toner particle size distribution can be measured at once.

  As the type of the cascade impactor, a type called an under sensor sampler is particularly preferable. For example, Model AN-200 manufactured by Tokyo Direc Co., Ltd., low volume air sampler AN-200 type Andsen type manufactured by Shibata Kagaku Co., Ltd., etc. It is. Here, the principle of the cascade impactor and the under sensor sampler will be further described.

  The fluid ejected in the vertical direction from the nozzle (here, the air sucked by the pump) as in the upper impactor unit shown in FIG. 1 suddenly changes direction, but of the particles that have been on the fluid streamline until then. The particles with large inertia do not survive the streamline, move in the vertical direction as they are, collide with the collision plate, and are attached and collected. Particles with low inertia escape the collision and go to the next stage with the air current. That is, in the cascade impactor, each stage of the impactor unit is one fluid classifier. In each impactor, the larger the airflow jet velocity from the nozzle, the smaller the nozzle diameter d (FIG. 1), and the shorter the distance L (FIG. 1) from the nozzle tip to the collision plate, the smaller the collision plate. Will be collected, and the classification diameter will be small. Cascade impactors classify and collect fine particles or aggregated particles contained in the airflow to be sucked into each aerodynamic diameter by arranging the impactor units in an order that the classification diameter decreases toward the downstream. can do.

  There are various types of multistage cascade impactors, but the 8-stage multistage cascade impactor devised by Andersen is generally called the Andersen Sampler, and is designed for a constant flow rate of 28.3 L / min. The relationship between the nozzle diameter and the flow velocity at each stage is as shown in Table 1 below.

The number of stages of the under sensor sampler is preferably 2 stages or more, more preferably 4 stages or more, and still more preferably 8 stages or less. If the number of stages is nine or more, the distribution can be measured more accurately, but the measurement becomes complicated and a significant effect cannot be obtained for the scattering evaluation.
Each stage of the under sensor sampler is set as shown in Table 2 below, for example.

  The ninth embodiment relates to a suction air flow rate in a scale of a preferable separation device (measuring instrument) of the under-sensor sampler. That is, by using an under sensor sampler with a suction air flow rate of 28.3 L / min, a standard product of an under sensor sampler used for environmental dust evaluation and the like can be used, which is preferable from the viewpoint of compatibility. Thus, it is possible to evaluate the toner scattering property reflecting the actual behavior of the toner particle group in the gas phase in the actual machine.

Here, an under sensor sampler suitable for implementing the present invention will be described with reference to FIG. FIG. 12 is a schematic view showing a configuration of a cascade impactor configured to collect a group of toner particles by an impactor unit.
The under sensor sampler 81 is a device in which collectors by the inertial collision method are combined in multiple stages for each target aerodynamic diameter.

  The under sensor sampler 81 generally includes an inhalation device (toner scattering model device and connection portion) 82, a pipe portion 83, a connection portion (throat) 84, a main body 85, an intake port 86, and a pump (not shown). . In the main body 85, eight filters 87a to 87h having holes of different sizes are provided. The under sensor sampler 81 is sucked from the suction port 86 by a pump (not shown). In this example, the suction flow rate from the suction port 86 is preferably about 28.3 (L / min). Although the pipe part 83 is curved in the drawing, it may be an appropriate flow path depending on a method for attaching a measurement target.

  By sucking the gas inside the main body 85 from the suction port 86, the toner particles move on the airflow in the order of the suction device 82, the pipe 83, the connection portion 84, and the main body 85. The filters 87a to 87h inside the main body 85 have holes that become smaller in order from 87a to 87h, and are divided into eight stages 0 to 7 by the filters 87a to 87h.

  The aerodynamic diameter distribution of the toner particles can be evaluated according to which of the stages 0 to 7 the toner particles have reached. Specifically, it is evaluated as shown in Table 2 above. The toner particles divided into the stages 0 to 7 are collected by a plate provided for each of the filters 87a to 87g.

  Here, a method for evaluating the toner scattering property will be described. Basically, when there are more particles with a small aerodynamic diameter, it is evaluated that the scattering property is high. Specific scattering evaluation criteria will be described below, but the scattering evaluation criteria vary depending on the experimental method and purpose, and are not necessarily limited to the following examples.

Hereinafter, the weight of stages 0 to 2 is X, the weight of stage n after stage 3 is Y _n , and the total of Y ₃ to Y ₇ is Y.
In a predetermined toner scattering model, a toner having a small Y value is a toner that is difficult to scatter, and a toner that is more difficult to scatter is a toner having a smaller absolute value of X + Y. Further, the toner is more difficult to scatter as Y / X is smaller, and the toner is more difficult to scatter as Y _n > Y _{n + 1} .

Further, the toner scattering property evaluation system in the present invention introduces a toner scattering device for generating scattered toner in an air flow, and an air flow including the scattering toner generated by the toner scattering device by dry and aerodynamic force, It consists of a separation device with multiple separation parts that separate and classify particles with low scattering properties and particles with high scattering properties, and evaluate the level of toner scattering properties based on the fine powder content of the classified size. It is comprised so that it may carry out.
With the toner scattering property evaluation system, it is possible to evaluate the toner scattering property according to the model case of toner scattering, and it is possible to evaluate the toner scattering property reflecting the actual behavior of the copying machine or printer.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited at all by these Examples.

The following were prepared as observation toners for evaluation of toner scattering properties and image quality (background stain).
Toner A: Weight average particle diameter of 5.4 μm, ratio of less than 4.00 μm on a volume basis 2.62%
Toner B: ratio of weight average particle diameter 5.8 μm, volume basis less than 4.00 μm 2.20%
In addition, the said weight average particle diameter and particle size distribution are the values measured as follows with the Coulter Multisizer II (Coulter company make) measuring apparatus.
First, 0.1 to 5 ml of polyoxyethylene alkyl ether as a dispersant is added to 120 ml of an electrolytic aqueous solution prepared to about 1% NaCl aqueous solution using primary sodium chloride, and 8 mg of a measurement sample (toner) is added thereto.
The electrolytic solution in which the toner is suspended is subjected to a dispersion process for about 1 minute with an ultrasonic disperser, and the measurement device is used to measure particles having a particle diameter of 2.00 μm or more and less than 40.30 μm using an aperture of 100 μm. did. That is, the measurement channel is 2.00 to less than 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. Less than 35 μm; less than 6.35 to less than 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Thirteen channels of 20-25.40 μm; 25.40-32.00 μm; 32.00-40.30 μm were used.

[Evaluation of toner scattering properties]
In this embodiment, a measurement system provided with a toner scattering device (dispersing means) 51 and a separation device (inertial collision type particle diameter measuring device: under-sensor sampler) 52 as shown in FIG. 13 was used. The toner scattering device shown in FIG. 13 is the same as that shown in FIGS. 3 and 4 in principle. 13 is an under-sensor sampler configuration shown in FIG. 12, and assumes a constant flow rate of 28.3 L / min under the setting conditions shown in Tables 1 and 2. Scale.
Although not shown in FIG. 13, the system of FIG. 13 is installed in an environment (space) provided with humidity control means 85, and the temperature and humidity of the entire apparatus is set to 5 to 40 ° C. and the relative humidity is 13 to 98 RH%. It can be controlled. The air nozzle 53 of the toner scattering device (dispersing means) 51 in FIG. 13 is an air nozzle having an opening diameter of 2 mm, and is supplied with an air flow having a pressure of 0.3 MPa. The opening size of the mesh 84 is 795 mesh.
In this embodiment, the toner and the carrier are mixed and accommodated in the toner scattering device. The carrier is a ferrite carrier of about 34 μm, and the same toner A and toner B are used. In the measurement, first, a fixed amount of a mixed sample in which the toner and the carrier were mixed at a weight ratio of 5: 100 for 5 minutes with a turbuler mixer was weighed and accommodated in a toner scattering device.

After a mixed sample of toner and carrier was put into the toner scattering device, it was separated and classified according to the following procedure and measured.
(1) The three-way valve 56 is set to the bypass channel 57 and the suction means is started up.
(2) Wait until the suction flow rate of the suction means 58 reaches a predetermined flow rate.
(3) Further, the humidity control means 55 is activated and waits for the surrounding temperature and humidity to reach a predetermined value.
(This time, the temperature is 10 ° C and the relative humidity is 15%.)
(4) The three-way valve is switched to the toner scattering device 51 and the air nozzle 53 is activated immediately.
(5) The entire area of the mesh portion 54 of the toner scattering device 51 is repeatedly scanned by the air nozzle 53 for a predetermined time, and the toner particles are scattered.
(6) The humidity control means 55 and the suction means 58 are stopped, and the mass of the toner particles collected on each stage of the separation device (under sensor sampler) 52 is measured.
(7) From the charged amount of toner (5/100 of the mixed sample), the mass-based ratio of the toner collected on each stage is obtained.

The mass-based ratio of the toner collected in stages 3 to 7 obtained as described above was as follows.
Toner A: 2.4%
Toner B: 3.8%

  From the above results, according to the measurement method used in the conventional toner particle size measurement (measured value by Coulter Multisizer in this example), the toner A has more fine particles having a volume basis of less than 4.00 μm. Many of them are highly scattered and are evaluated to easily cause background stains. However, according to the evaluation method of the present invention, the toner B is evaluated to have higher scattering properties than the toner A and is likely to cause background stains. The result is different.

[Evaluation of image quality (background stain)]
Using the toner A and toner B, the image quality (background stain) was evaluated.
Developers each consisting of 4% by weight of toner A and toner B and 96% by weight of a copper-zinc ferrite carrier having an average particle diameter of about 35 μm coated with a silicone resin were prepared. Using each developer, RICOH Imagio Neo 450, which can print 45 sheets of A4 size paper per minute, continuously prints 5000 sheets of an image area of 0.5% in an environment with an air temperature of 10 ° C and a relative humidity of 15%. After that, a blank paper image is further output, the blank paper image is stopped during development, and a total of three toners on the both ends and the center of the photosensitive member after development are transferred to the tape, and the difference from the image density of the untransferred tape. Was measured with a 938 spectrodensitometer (manufactured by X-Rite), and the following values were obtained.
Average value of toner A: 0.01
Average value of toner B: 0.03
That is, it was confirmed that toner B has a higher degree of background stain, and toner B has higher toner scattering properties than toner A.

As described above, the inertial collision method uses scattered toner generated from a toner scattering device configured to match the model case of actual toner scattering, rather than the fine powder amount based on the volume average particle diameter measured in the liquid phase by a Coulter Multisizer. By calculating the content of fine powder of a predetermined size that is classified by gas dynamics (especially aerodynamics), it is possible to relatively compare the scattering properties of toners, and to determine the degree of occurrence of background stains. It can be evaluated more easily. That is, the actual behavior of the toner particle group in the gas phase in the actual machine can be reflected.
That is, according to the toner scattering property evaluation method and the toner scattering property evaluation system, the scattering property due to the air current of the toner, the aggregation in the air current due to humidity, the influence of the particle shape and aerodynamic characteristics, the charging property, etc. Thus, the toner scattering property can be evaluated, and further, the characteristics of the toner against background stains can be evaluated.

FIG. 6 is a schematic view schematically showing a cross section of a main part of a separation device for separating and classifying toner particles by an inertial collision method in a second embodiment of the present invention. FIG. 2 is a schematic view showing a configuration of a twin impinger suitable as a separating device for separating and classifying toner particles by an inertial collision method in the present invention. FIG. 10 is a schematic diagram illustrating an example in which toner in a two-component developer housed in a toner scattering device is introduced into a separation device by suction in the third embodiment of the present invention. FIG. 10 is a schematic diagram illustrating an example in which toner in a two-component developer housed in a toner scattering device is blown by an air nozzle and introduced into a separation device in a third embodiment of the present invention. FIG. 5 is an enlarged schematic diagram illustrating a scattering state of a toner and a carrier constituting the two-component developer in FIG. 4. FIG. 10 is a schematic diagram illustrating a configuration example of a toner scattering device that generates scattered toner in an air stream by a stirring blade in a fourth embodiment of the present invention. It is the schematic which shows the structural example of the toner scattering apparatus which generate | occur | produces a scattering toner in airflow with the stirring roll with a stirring blade in the 4th Embodiment of this invention. FIG. 10 is a schematic diagram illustrating a configuration example of a toner scattering device that generates scattered toner in an air stream by fluidizing a particle group including a toner base by a fluidizing unit in a fifth embodiment of the present invention. FIG. 10 is a schematic diagram illustrating a configuration example of a toner scattering device that generates scattered toner in an air flow by spraying toner existing with a carrier by an air flow in a sixth embodiment of the present invention. It is the schematic which shows typically the magnetic brush formed on a magnetic roll in FIG. FIG. 11 is an enlarged view schematically illustrating, as an example, a two-component developer including a toner and a carrier in FIG. 10. It is the schematic which shows the structure of the cascade impactor made to collect a toner particle group by the impactor unit in the 7th Embodiment of this invention. It is the schematic which shows the structure of the under sensor sampler used for the Example of this invention. It is the schematic diagram (a) which shows a mode that an air flow flows out from a slit-shaped opening with directionality in the 5th Embodiment of this invention, and the top view (b) which shows a turning-type distribution | circulation member.

Explanation of symbols

(Figure 1)
1 Nozzle 2 Collision plate 3 Distance L from nozzle tip to impact plate
(Figure 2)
41 Twin Impinger 42 Mouthpiece Adapter 43 Throat 44 Neck 45 Upper Collision Chamber 46 Coupling Tube 47 Inlet 48 Lower Jet Collection Portion 49 Lower Collision Chamber (Figure 3)
30 Toner scattering device 31 Conductive screen with mesh structure 32 Toner and carrier mixture (developer)
(Figs. 4 and 5)
21 Conductive screen with mesh structure (mesh part)
22 Toner and carrier mixture (developer)
23 Air nozzle 24 Carrier 25 Toner (Figs. 6 and 7)
64 stirring blades 64F stirring blades 64R stirring rolls 65 air flow 66 toner or toner-carrier mixture (developer)
(Fig. 8)
70 Toner scattering device 71 Toner powder container 72 Toner powder 73 Mesh member (FIGS. 9, 10, and 11)
91 Mixing container 92 Stirring roll 93 Magnetic roll 94 Restricting means 95 Air supply means 96 Blow air flow 97 Air nozzle 98 Magnetic brush 99 Toner (FIG. 12)
81 Under sensor sampler 82 Inhalation device 83 Pipe part 84 Connecting part (throat)
85 Body 86 Suction port 87a-h Filter (Fig. 13)
51 Toner scattering device (dispersing means)
52 Separation device (under sensor sampler)
53 Air nozzle 54 Mesh part 55 Humidity control means 56 Three-way valve 57 Bypass flow path 58 Suction means (FIG. 14)
5 Opening 6 Distribution member 7 Air flow

Claims (12)

  An air flow including scattered toner particles generated by the toner scattering device is introduced into the separation device by dry and aerodynamic force, and the toner particles in the air flow are scattered by a plurality of separation units arranged in the separation device. The toner scattering property evaluation is characterized by separating and classifying the particles into a particle group having a low property and a particle group having a high scattering property, and determining the content of the classified fine powder of a predetermined size to evaluate the level of toner scattering property. Method.   The toner scattering property evaluation method according to claim 1, wherein the air flow is an air flow.   3. The toner according to claim 1, wherein the toner has either a configuration including a toner base alone containing at least a binder resin and a colorant, or a configuration including the toner base and an external additive. Toner scattering property evaluation method.   4. The toner scattering property evaluation method according to claim 1, wherein the toner to be evaluated is scattered from a two-component developer mixed with a carrier.   5. The separator according to claim 1, wherein the separating device separates and classifies toner particles into a particle group having a low scattering property and a particle group having a high scattering property by an inertial collision method. Toner scattering property evaluation method.   6. The toner scattering property evaluation method according to claim 1, wherein the toner scattering device includes a toner agitation unit, and the agitation unit generates scattering toner in an air stream.   6. The toner scattering device includes a fluidizing means for particles, and fluidized means fluidizes a particle group including a toner base to generate scattered toner in an air stream. The toner scattering property evaluation method according to any one of the above.   The toner scattering device includes magnetism generating means, and while holding the carrier by the magnetic force of the magnetism generating means, the toner existing with the held carrier is blown by an air flow to generate the scattering toner in the airflow. The toner scattering property evaluation method according to any one of claims 1 to 5.   9. The toner scattering property evaluation method according to claim 1, wherein an air flow containing the scattering toner particles is conditioned.   The separation device includes a plurality of impactor units that introduce suction airflow containing scattered toner particles from a nozzle by a suction unit and collide the jetted airflow with a collision plate, and a group of particles having low scattering properties that are separated and classified in each impactor unit The toner scattering property evaluation method according to claim 1, wherein the toner scattering property evaluation method is a cascade impactor configured to collect particles having high scattering property.   The separation device is configured to introduce a predetermined suction air flow including scattered toner particles by a suction unit, and to separate and classify the particles into a group of particles having low scattering properties and a group of particles having high scattering properties by a plurality of impactor units. The toner scattering property evaluation method according to claim 10, wherein the toner scattering property evaluation method is an under sensor sampler, and the suction air flow is set to 28.3 L / min. A toner scattering device for generating scattered toner in the airflow;
Separation provided with a plurality of separation parts for separating and classifying into a group of particles having low scatterability and a group of particles having high scatter property by introducing an air flow including scattered toner generated by the toner scatter device by dry and aerodynamic force Consisting of equipment,
A toner scattering property evaluation system configured to evaluate the level of toner scattering property from the classified fine powder content of a predetermined size.

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