JPH1165160A - Developer and developing device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a developing device to realize high reliability and to prolong a service life by preventing a developer from being melt-stuck on a doctor blade as a controlling member of a toner layer occurring at the layer thickness controlling time of the toner layer on a developing roller being a developer carrier in the developer and the developing device provided with the developer. SOLUTION: This developing device 1 is constituted by providing a toner 51 being a developer, a developing roller 2 made of chloroprene rubber holding the toner 51 being fed from a toner feeding roller 4 on a surface and feeding the toner to an image carrier on which an electrostatic latent image is formed and a doctor blade 3 made of aluminum for controlling the thickness of the toner 51 on the developing roller 2. Then, for the toner 51, a material composed of a resin base material and a color material incorporated in the resin base material and moreover a material containing urea as the material causing an endothermic reaction are adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in an electrophotographic recording apparatus such as an electrophotographic copying machine or an electrophotographic printer,
The present invention relates to a developer for developing an electrostatic latent image and a developing device having the developer for performing such development, and particularly to forming a uniform thin layer of the developer on the surface of a development carrier and supplying the developer to an image carrier. And a developing device having the developer and performing such development.

2. Description of the Related Art Electrophotographic recording apparatuses such as electrophotographic copying machines and electrophotographic printers using an electrophotographic recording method are widely used due to their high speed, high resolution, and low noise. In the electrophotographic recording method, generally, a uniformly charged photoreceptor surface is exposed by a laser or the like according to image information to form an electrostatic latent image. Thereafter, in a developing step, the charged latent toner is adhered to the electrostatic latent image on the photoreceptor, developed and visualized. Next, after the toner on the photoreceptor is electrostatically transferred onto the recording paper, the toner transferred to the recording paper is fixed on the recording paper by heat, pressure, light, or the like, thereby obtaining a copy or a print.

In recent years, the cost and size of an electrophotographic recording apparatus which performs printing using the electrophotographic recording method have been reduced, and as a result, an apparatus having high reliability and high printing quality has been developed. It has become desired. And
As a result, such demands reach the components constituting the electrophotographic recording apparatus. That is, there is a need for improvements in each part of the electrophotographic recording apparatus configured to correspond to each step of the above-described electrophotographic recording method in order to meet the above-mentioned demands.

The present invention has been made in order to meet such a demand, and relates to a developing device for performing the above-described developing step of an electrophotographic recording device using an electrophotographic recording system as described above, and to improve its reliability.・ Longer life,
High reliability and high printing quality in electrophotographic recording devices,
It is intended to further reduce costs.

[0005]

2. Description of the Related Art A uniform thin layer of a developer is formed on a conventional developing device, in particular, a developer carrier, and the developer is supplied to an electrostatic latent image holding member provided in an electrophotographic recording device to perform development. In the developing device, a developer carrier close to the electrostatic latent image carrier, a developer supply member provided to be in contact with the developer carrier, and a developer There is known a device provided with a layer thickness regulating means for uniformly reducing the thickness of a developer on an agent carrier.

A developing process using the conventional developing device will be described with reference to FIG. The conventional developing device is a main component of the conventional electrophotographic recording apparatus 100 together with the photoconductor unit. In this developing device,
The developing roller 102 as a developer carrier rotates while being in contact with a sponge roller 104 as a developer supply member and a doctor blade 103 as a layer thickness regulating unit.

The toner, which is a developer carried to the contact portion with the developing roller 102 by the rotation of the sponge roller 104, is rubbed at the contact point and charged. The charged toner adheres to the surface of the developing roller 102 by its electrostatic force,
The rotation of the developing roller 102 causes the doctor blade 10 to rotate.
3 is carried to the abutment part. Doctor blade 103
Is pressed against the developing roller 102 by a predetermined urging force,
The toner adhering to the surface of the developing roller 102 is regulated to a desired constant thickness, and a toner layer as a developer layer having a uniform layer thickness is formed.

After that, the toner layer reaching the developing point, which is the contact portion of the photoconductor unit with the photoconductor 105,
According to the latent image formed on the photoconductor 105, a part of the latent image is consumed by moving to the surface of the photoconductor 105. That is,
The latent image is developed and visualized by the toner. And
On the other hand, in the toner layer on the developing roller 102, a portion where the toner is lost and a portion where the toner remains are generated according to the shape of the latent image. Due to the rotation of the developing roller 102, the residual toner layer after the development is again sponge roller 104.
Then, a new toner is attached to the portion where the toner has been lost, and the same developing process is repeated.

[0009]

However, in a developing process using a conventional developing device, a doctor blade 103 is used to form a uniform thin layer of toner on the developing roller 102 as described above. The thickness of the toner is regulated.
3 had a problem of fusing.

[0010] The fusion to the blade which occurs in the developing device does not occur from the beginning of use of the developing device, but gradually occurs while the developing device is operated for a long time. Then, when fusion to the blade occurs, the fusion site is changed to the developing roller 1.
In this case, the regulation of the thickness of the toner on the surface of the toner layer 02 makes it impossible to form a uniform toner layer. As a result, a streak-like toner layer can be removed from the toner layer on the developing roller 102. Then, in such a case, the quality of printing is completely degraded.

As described above, the fusion to the blade is a major problem that hinders the improvement of the reliability of the developing device and the improvement of the reliability and printing quality of the electrophotographic recording apparatus using the developing device. . However, in the developing device, regulation of the thickness of the toner layer is indispensable, and this is an unavoidable structural problem. Therefore, the solution has been considered to be a problem of a conventional developing device and an electrophotographic recording device using the developing device.

Accordingly, the present invention provides a novel developer which solves the above-mentioned problems and a developing device having the developer, and regulates the thickness of a toner layer on a developing roller as a developer carrier. Suppressing occasional fusion to the blade,
To provide a developer capable of increasing the reliability and extending the life of a developing device, and further, to increase the reliability, printing quality, and cost of an electrophotographic recording device, and to provide a developing device having the developer. It is.

[0013]

According to the first aspect of the present invention,
A developer comprising a resin base material and a colorant contained in the resin base material is characterized in that the developer further contains a substance causing an endothermic reaction. The invention according to claim 2 is
2. The developer according to claim 1, wherein the substance causing the endothermic reaction is at least one substance selected from the group consisting of urea, ammonium nitrate and potassium nitrate.

According to a third aspect of the present invention, there is provided a developer carrier which holds the supplied developer on the surface and supplies the developer to an image carrier on which an electrostatic latent image is formed. In a developing device having a regulating member for regulating the thickness of the developer on the developer carrier, the developer comprises a resin base material and a coloring agent contained in the resin base material, and causes an endothermic reaction. It is characterized by further containing a substance.

According to a fourth aspect of the present invention, in the developing device of the third aspect, the developer carrier is made of a material having a specific heat capacity larger than that of normal butyl rubber (NBR). According to a fifth aspect of the present invention, in the developing device of the third or fourth aspect, the regulating member is made of a material having a specific heat capacity larger than that of stainless steel.

According to the first aspect of the present invention, the developer is:
Even if the temperature rises, friction can be caused by endothermic reaction of a substance causing an endothermic reaction due to friction caused by the application of charge in the developing step. Therefore, it is possible to suppress the developer from being deteriorated due to a rise in temperature and being fused to the developing device, to prevent the performance of the developing device from being deteriorated, to increase the reliability, and to extend the life of the developing device.

According to the second aspect of the invention, the developer is:
Even if heat is generated on the surface due to friction caused by the charge applied in the developing process, the contained urea, ammonium nitrate, and potassium nitrate cause a dissolution reaction with moisture in the atmosphere to cause heat on the developer. Can be deprived.
Therefore, the developer is cooled due to the endothermic effect of the dissolution reaction of the urea and the like, and the temperature rise can be suppressed.

Therefore, the developer deteriorates due to the temperature rise,
The fusion to the developing device is suppressed, the performance of the developing device is prevented from lowering, the reliability can be increased, and the life of the developing device can be extended. According to the third aspect of the present invention, when the developer is supplied to the image carrier, the developer is rubbed on the developer carrier to impart a charge to the developer, thereby generating heat. Also, the developer can be cooled by an endothermic reaction of an endothermic substance contained in the developer.

Therefore, the developer deteriorates due to the temperature rise,
Fusing in the apparatus is suppressed, performance of the apparatus such as printing quality is prevented from deteriorating, and high reliability can be achieved, and the life of the apparatus can be extended. According to the fourth aspect of the present invention, when supplying the developer to the image carrier, the developer is rubbed on the developer carrier to impart a charge to the developer, thereby generating heat. In addition, since the developer carrying member that carries the developer has a large specific heat capacity, it is possible to suppress a rise in the temperature of the developer.

Therefore, the developer deteriorates due to the temperature rise,
The fusion in the device is suppressed, the performance of the device is prevented from deteriorating, the reliability can be increased, and the life of the device can be extended. According to the fifth aspect of the present invention, when the developer is supplied to the image carrier, the developer is rubbed on the developer carrier to impart a charge to the developer, thereby generating heat. However, since the regulating member that contacts the developer and regulates the thickness thereof has a large specific heat capacity, it is possible to suppress the temperature rise of the developer on the regulating member.

Therefore, the developer deteriorates due to the temperature rise,
Fusing inside the device, especially fusing to the regulating member, is suppressed, and a decrease in the performance of the device is prevented, enabling high reliability, and extending the life of the device.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventor has investigated the conditions under which the fusion of toner as a developer, which occurs during the regulation of the thickness of a developer layer, which is a problem of the above-described conventional developing device, is caused. Was. As a result, it has become clear that the fusion of the toner does not occur in the early stage of use of the developing device, but occurs when the developing device is operated for a long time.

By this long-term operation, external additives such as inorganic fine particles of titania and silica generally added to the surface of the toner to improve the fluidity of the toner and to control the charging property are obtained. It has been found that the resin matrix embedded and lost in the resin matrix constituting the toner, and the resin matrix inside the toner normally supposed to be hidden by the external additive on the surface is exposed on the toner surface.

Further, when the resin base material is exposed on the surface of the toner, if the surface temperature of the toner rises to the glass transition temperature or higher in the apparatus due to friction or the like for applying electric charges, it is found that the fusion of the toner occurs. Was. By clarifying the problematic phenomena, it became possible to solve it by the following method.

First, it is conceivable to suppress the loss of the external additive in order to prevent fusion. That is, most of the loss of the external additive is caused by the embedding into the resin base material inside the toner which occurs during the long-term operation, and therefore, it is conceivable to increase the strength of the resin as compared with the conventional one. Actually, when such an attempt was made, the resin was an organic substance, and there was a limit in the improvement of its strength.Moreover, the resin was sufficiently suppressed from being embedded in an external additive that was mostly inorganic. Cannot be achieved, and the effect is not sufficient.

In view of the above, it was conceived to prevent a rise in the temperature of the toner, which is another factor that causes the fusing phenomenon, and was performed next. Specifically, for the toner, a substance that causes an endothermic reaction is blended in order to suppress a rise in the temperature of the toner,
The phenomenon that the toner temperature becomes higher than the glass transition temperature of the resin base material constituting the toner on the developing material carrier such as the developing roller is less likely to occur, and the fusion is less likely to occur even if the resin base material is exposed on the toner surface. The configuration is as follows.

As for the endothermic reaction used herein, when a thermodynamic process such as a chemical reaction or a change in state proceeds while absorbing heat, the chemical reaction or change in the state is not detected. Point and say. Here, a substance causing an endothermic reaction (hereinafter abbreviated as an endothermic substance as appropriate) and a mechanism for preventing the toner temperature from rising will be further described.

As the substance causing the endothermic reaction, for example, a substance capable of removing heat from the outside when dissolved in water (dissolution reaction) can be used. Specifically, urea, ammonium nitrate, potassium nitrate and the like can be used. When the endothermic substance added to the toner is present inside the resin constituting the toner, the endothermic substance does not touch the atmosphere due to the action of an external additive such as inorganic fine particles already added, and the endothermic dissolution reaction does not occur. Don't wake up.

However, as described above, when the developing device is operated for a long time, the toner is physically deteriorated, that is, when the external additive on the toner surface disappears from the surface and the resin containing the heat absorbing substance is exposed on the toner surface, It interacts with and absorbs moisture that constitutes atmospheric moisture. At this time, an endothermic dissolution reaction of the endothermic substance occurs, and the temperature of the toner decreases.

Therefore, the effect of the endothermic dissolution reaction is exerted on the deteriorated toner. If the temperature of the toner is equal to or lower than the glass transition temperature of the resin constituting the toner, the fusion of the toner to a member for regulating the layer thickness such as a doctor blade is suppressed, and the phenomenon that causes a problem in the developing device is suppressed. You. Next, for portions other than the toner, when a charge is applied to the toner by friction or when the layer thickness of the toner layer is regulated, a developing member such as a regulating member such as a doctor blade or a developing roller is developed so that the temperature of the toner is hardly increased. A material having a large specific heat capacity is selected for the material carrier to constitute a developing device.

More specifically, a stainless steel material is often used for the regulating member, and the specific heat capacity of the stainless steel material is 0.11 cal / g · deg. Therefore, instead of stainless steel, a material having a higher specific heat capacity, for example, aluminum (specific heat capacity is 0.2 c
al / g · deg) or a resin material such as polyethylene (specific heat capacity 0.55 cal / g · deg) or nylon (specific heat capacity 0.5 cal / g · deg) to regulate the layer thickness of the toner layer. At times, it is possible to make it difficult for the toner temperature to rise.

Similarly, conventionally, a urethane rubber (a specific heat capacity of 0.45 cal / g · deg), a silicone rubber (a specific heat capacity of 0.37 cal / g · deg),
Normal butyl rubber (NBR) (specific heat capacity 0.47 ca
l / g · deg) or the like is often used, but instead of these synthetic rubbers, synthetic rubber having a higher specific heat capacity, for example, chloroprene rubber (CR) (specific heat capacity 0.52 cal / g) By using (deg), it is possible to make it difficult for the temperature of the toner to rise when regulating the thickness of the toner layer.

Based on the above description, a developer according to an embodiment of the present invention and a developing device having the same will be described below.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developer according to an embodiment of the present invention will be described, and a developing apparatus having the same will be described in detail with reference to the drawings. (Example 1) Preparation of a toner as a developer of an example according to the present invention will be described.

The toner according to the embodiment comprises a resin base material and a coloring agent contained in the resin base material, and has a structure further containing a substance causing an endothermic reaction. Specifically, a polyester resin having an average molecular weight of about 3500 is used as a resin base material, and 5 parts by weight of carbon black as a coloring agent and 4 parts by weight of a charge control agent are added to 100 parts by weight of the main binder.
Urea is prepared by internally adding 10 parts by weight of urea as a substance which causes an endothermic reaction, and further provided as an external additive of inorganic fine particles having a size of about 10 nm so as to cover the surface thereof.

The obtained toner is negative and non-magnetic,
The volume resistivity is about 10 ¹⁴ Ωcm. The average particle size has a volume average of 8 μm. Thus, the appearance of the color and the like was not different from that of the conventional toner, and similarly, a toner having appropriate fluidity and electric charge characteristics was prepared. (Embodiment 2) An embodiment according to the present invention, and
A developing device having the developer prepared in the above will be described.

FIG. 1 is a cross-sectional view illustrating the structure of a main part of a developing device according to an embodiment of the present invention. The developing device 1 according to the embodiment holds a toner 51 as a developer and a toner 51 supplied from a supply roller 4 for supplying the developer on the surface and holds the toner 51 on which an electrostatic latent image is formed. Roller 2 which is a developer carrier to be supplied to a body (not shown)
And a doctor blade 3 as a regulating member for regulating the thickness of the toner as the developer on the developer carrier 2.

The toner 51, which is a developer, comprises a resin base material and a coloring agent contained in the resin base material, and further contains a substance that causes an endothermic reaction. Specifically, the toner 51
Is the toner shown in Example 1. The supply of the toner 51 to the supply roller 4 is performed from the toner cartridge 5 via two transfer rollers 6 and 7.

The developing roller 2 is obtained by imparting conductivity to synthetic rubber, and has a volume resistivity of 10 ⁸ Ωcm in this embodiment.
It is. The synthetic rubber material is CR. The doctor blade 3 is made of aluminum. And the supply roller 4
Is made of a sponge that is rotatable about a rotation axis and has conductivity. To be conductive,
By applying a voltage, an electric charge is injected into the toner 51 by the electric charge injection effect, and the electric charge can be applied. In the present embodiment, a urethane sponge is used,
-500 V is applied.

FIG. 2 is a view for explaining development performed by the developing device according to the embodiment of the present invention. The present embodiment is an embodiment according to the present invention by combining with a photoconductor unit 11 known as a conventional technique to form an image forming apparatus 12 and further including a fixing roller 21 known as a conventional technique. An electrophotographic recording device 31 using a developing device is configured. Hereinafter, the developing operation and the printing operation on the recording paper will be specifically described with reference to FIG.

In the developing device 1 according to the embodiment of the present invention, the developing roller 2 rotates while being in contact with the supply roller 4 and the doctor blade 3 as the layer thickness regulating means. The toner 51 carried to the contact portion with the developing roller 2 by the rotation of the supply roller 4 is rubbed and charged at the contact point. The charged toner 51 adheres to the surface of the developing roller 2 by the electrostatic force, and is carried to the contact portion with the doctor blade 3 by the rotation of the developing roller 2.

The doctor blade 3 is in pressure contact with the developing roller 2 with a predetermined urging force, and regulates the toner 51 attached to the surface of the developing roller 2 to a desired constant thickness. A barrel toner layer is formed. Thereafter, the photosensitive drum 13 is sent to the photosensitive drum 13 of the photosensitive unit 11, and a voltage is applied to the photosensitive drum 13 so that electric fields in opposite directions are generated in the image portion and the background portion of the latent image formed thereon. In this embodiment, a voltage of -300 V is applied so that the image portion is about -100 V and the background portion is at -600 V. The toner layer that reaches a developing point, which is a contact portion between the photosensitive drum 13 and the developing roller 2, is partially formed on the photosensitive drum 13 by a laser beam according to a latent image having the above-described voltage characteristics. It is consumed by moving to the drum 13 surface. That is, development and visualization of the latent image by the toner 51 are performed.

On the other hand, a portion where the toner 51 is lost and a portion where the toner 51 remains are generated in the toner layer on the developing roller 2 according to the shape of the latent image. Due to the rotation of the developing roller 2, the residual toner layer after the development returns to the contact portion with the supply roller 4 again, a new toner 51 is attached to the portion where the toner 51 has been lost, and the same developing process is repeated.

The layer of the toner 51 formed by development on the photosensitive drum 13 is provided so as to be in contact with the photosensitive drum 13 and uses a rotatable transfer roller 14 so that the transfer roller 14 is The image is transferred onto the recording paper 15 conveyed between the drum 13. Next, the recording paper 15 to which the toner 51 has been transferred passes through the fixing roller 21 to fix the toner 51, and the information provided by the laser beam is fixed as a print on the recording paper.

Next, two developing devices having exactly the same configuration except that the constituent materials of the doctor blade were different were similarly manufactured. The materials used for the doctor blade are polyethylene and nylon. In the following, the developing device in which the doctor blade is made of aluminum is referred to as Example A,
A developing device having a doctor blade made of polyethylene is called Example B, and a developing device made of nylon is called Example C.

Each of the manufactured developing devices of the embodiments B and C is combined with the above-mentioned conventional photoconductor unit 11 in the same manner as in the embodiment A to constitute an image forming apparatus. By providing the fixing roller 21,
An electrophotographic recording apparatus using a developing device according to an embodiment of the present invention is configured. Then, development and printing on recording paper were possible in the same manner as in Example A.

Next, the occurrence of the phenomenon of the toner fusing to the doctor blade was examined using an electrophotographic recording apparatus constituted by using the developing apparatus of this embodiment. As a comparative example, a conventional electrophotographic system using a conventional developing device having exactly the same configuration except that a toner containing no endothermic substance was used for the toner, the doctor blade was made of stainless steel, and the developing roller was made of NBR. Using a recording device,
A comparison of the properties was made.

The results are shown in the table below. When the developing device of the present embodiment according to the present invention is used, the time from the start of use to the occurrence of the fusing phenomenon is larger than that of the conventional device of the comparative example. The time required for the developing device to become unusable due to a decrease in print quality, that is, the life of the developing device was increased by 2 to 4 times.

[0049]

[Table 1]

It has also been found that the effect of extending the life is particularly remarkable when a resin material such as polyethylene or nylon is used for the doctor blade. As described above, according to the present invention, it is possible to provide a developing device capable of suppressing fusion of a toner to a doctor blade as compared with a conventional device.

[0051]

According to the first aspect of the present invention, it is possible to prevent the developer from being deteriorated due to a rise in temperature and from being fused to the developing device, to prevent the performance of the developing device from being deteriorated, and to improve the reliability. And the service life can be extended. Claim 2
According to the described invention, the developer is cooled due to the endothermic effect of the contained urea, ammonium nitrate, and potassium nitrate, and the temperature rise can be suppressed.

Therefore, the developer deteriorates due to the temperature rise,
The fusion to the developing device is suppressed, the performance of the developing device is prevented from lowering, the reliability can be increased, and the life of the developing device can be extended. According to the third aspect of the present invention, it is possible to prevent the developer from being deteriorated due to a rise in temperature and from being fused to the inside of the apparatus, to prevent a decrease in performance such as printing quality of the apparatus and to increase reliability. And the service life can be extended.

According to the fourth aspect of the present invention, it is possible to prevent the developer from being deteriorated due to a rise in temperature and from being fused to the inside of the apparatus. , Its life can be extended. According to the fifth aspect of the present invention, it is possible to prevent the developer from being deteriorated due to a rise in temperature and fusing in the apparatus, and in particular, from fusing to the regulating member, thereby preventing the performance of the apparatus from deteriorating. High reliability, and the service life can be extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main configuration of a developing device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating development performed by a developing device according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a developing process of a conventional electrophotographic recording apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 developing device 2 developing roller 3 doctor blade 4 supply roller 5 toner cartridge 6,7 transport roller 11 photosensitive unit 12 image forming device 13 photosensitive drum 14 transfer roller 15 recording paper 21 fixing roller 31 electrophotographic recording device 51 toner

Claims (5)

[Claims] 1. A developer comprising a resin base material and a coloring agent contained in the resin base material, further comprising a substance which causes an endothermic reaction. 2. The developer according to claim 1, wherein the substance causing the endothermic reaction is at least one substance selected from the group consisting of urea, ammonium nitrate and potassium nitrate. 3. A developer carrier, a developer carrier that holds the supplied developer on a surface thereof, and supplies the developer to an image carrier on which an electrostatic latent image is formed. A developing device comprising a regulating member for regulating the thickness of the developer, wherein the developer comprises a resin base material and a colorant contained in the resin base material, and further contains a substance which causes an endothermic reaction. A developing device. 4. The developing device according to claim 3, wherein the developer carrier is made of a material having a specific heat capacity larger than a specific heat capacity of normal butyl rubber (NBR). 5. The developing device according to claim 3, wherein said regulating member is made of a material having a specific heat capacity larger than that of stainless steel.