JPS5945468A - Electrostatic developing device for latent image - Google Patents

Abstract

PURPOSE:To enable the formation of a uniform thin layer of a one-component developer by bringing a flexible powder coating member and a movable developer carrying body into surface contact with each other and preventing the contact of the end part of the flexible powder coating member with the developer carrying body. CONSTITUTION:A developing roll 1 is a developer carrying body and is a conductive hollow cylinder consisting of metal such as stainless steel which is supported rotatably in an arrow direction. An elastic blade 2 is a developer powder coating member which is made of an elastic material such as urethane rubber. A one-component developer 3 is contained in a developer vessel 4. When a developer roll 1 is grounded and the roll 1 is rotated at a prescribed speed in an arrow direction, a good thin layer of a uniform thickness is formed on the surface of the roll 1.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to an electrophotographic device or an electrostatic recording device,
The present invention relates to an electrostatic latent image developing device that visualizes an electrostatic latent image formed on a photoreceptor or dielectric material using a one-component developer consisting only of magnetic or non-magnetic toner.

[Prior art and its problems]

Developing is t? This is done by electrostatically attracting colored fine powder called toner, which is charged with a polarity opposite to that forming the electrostatic latent image. In addition to single-component developers consisting only of powdered toner, there are also two-component developers consisting of a mixture of powdered toner and magnetic powder called a carrier or fine powder such as resin or glass. In a two-component developer, the toner is charged by friction with the carrier, and the toner is reliably charged.

On the other hand, in order to maintain a constant development density, the mixing ratio of toner and carrier, that is, the toner preparation must always be maintained constant. A one-component developer made only of toner does not require such toner four-time management, and is superior to a two-component developer in its ease of handling.

- Component developers are classified into non-magnetic and magnetic.

Non-magnetic toner is generally a mixture of resin powder and a coloring agent such as carbon, and magnetic toner is a mixture of resin powder and magnetic powder.

- Conventional general developing devices using component developers have used rigid blades, elastic blades, etc. as developer coating parts. However, in order to form a thin layer of developer on the surface of the developer carrier with the rigid blade, a high level of mechanical strength is required in setting the gap between the rigid blade and the developer carrier, and aggregated toner and foreign matter If the temple blocks this gap, unevenness will occur in the thickness of the developer layer. On the other hand, in all conventional examples in which an elastic blade is used as a developer powder application part, developer is applied to the surface of the developer carrier by pressing the edge of the blade or a certain area including the edge against the developer carrier. The aim was to form a thin M. When forming a thin layer using this contact method, the pressure force is concentrated on the edges of the grade, so the shape of the edges, wear conditions, contact conditions, etc. have a subtle effect on the flexibility of the thin layer being formed. It has been difficult to stably form a uniform developer layer with a constant thickness. Furthermore, due to the same reason that the pressing force is concentrated, the developer layer becomes very thin and the image density of the developed image becomes insufficient. In addition, when applying a load to the developer by creating a friction zone between the developer carrier 411 and the developer gold powder member, the above-mentioned conventional method can be used. Since the contact with the developer carrier (4-t) is small, the developer is attached to the surface of the developer carrier (tr#L-) and the contact between the developer carrier and the developer powder application area 1g is 1g. - Acquire sufficient friction zone '1iLf17+ load when passing Ii t'iB (
There was a bug where it was not possible to do 1.

[Purpose of the invention]

This invention is an improvement on all the drawbacks of the conventional device mentioned above.
Magnetic or non-magnetic component 1 is applied to the surface of the movable developer carrier.
A first object of the present invention is to provide a static latent image developing device capable of forming a uniform thin layer of urine agent.

A second object of the present invention is to provide a silent 11C latent image developing device capable of forming a thin layer of sufficiently and uniformly charged magnetic wire saw Q non-magnetic component developer on the surface of a movable developer carrier. It is about providing.

[Summary of the invention]

In the present invention, a movable developer carrier, for example, a developing roll,
A flexible powder coating member, such as a comb blade, is brought into surface contact with its belly surface, and the free end of the OJ' powder coating member, that is, the edge located downstream 6111 of the developer flow, is allowed! The present invention is characterized in that it is set so that it does not come into contact with the surface of the dust carrier, and by setting it in this way, the object of the present invention is achieved.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained.31 According to the present invention, it is possible to set a large contact surface Aλ between the surface of the movable developer carrier and the piling powder coating member, and Since the edge of the flexible blood powder cavity does not come into contact with the surface of the controlled developer carrier, the pressure contact force will not be concentrated on the microscopic surface (1). It is possible to reduce the non-uniformity of the pressure contact force caused by wear and the like, and it is possible to form a more uniform agent layer.

In addition, since the contact area between the IJT dynamic developer carrier surface and the flexible grinding member is large, the developer is subjected to friction under pressure for a longer period of time when passing through this contact area. Therefore, the current heel agent has a uniform and sufficient friction zone...11L load'J! c can be obtained.

Thus, according to the present invention, the 7ζ
Formation of a uniform thin layer of the 5A ball can be achieved by this, which allows for good performance of the static 11 immersion process.

[Embodiments of the invention]

Hereinafter, IJJ will explain this example in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. The current 1y roll 1 is the developing jill: I'! It is a durable hollow cylinder made of gold such as stainless steel and is rotatably supported in the direction of the arrow in the figure. .

The elastic blade 2 is coated with the developer for 4 minutes, then the urethane 7
It is made of an elastic body such as -f-mu. Honji b′i! In example i, a urethane rubber grade with a hardness of 30 degrees and a thickness of 2 mm was used, and as shown in the figure, it was brought into contact with the current 1y roll 1 at the j-back surface. - The component developer 3 is housed inside the developer container 4. In this example, a non-magnetic toner having an average particle diameter of 10 μm and made of polystyrene, carbon + 4Tf 1-f-C suppressant, etc. was used as the -component developer. The developing roll 1 is placed on the ground and the circumferential speed is 100+m/in the direction of the arrow in the figure.
When the roller was rotated at a speed of 1.5 seconds, a uniform thin layer of the monocomponent developer could be formed on the surface of the developing roller 1. Further, this developing device 1J was installed as shown in the figure with a gap of 350 μm between the selenium photosensitive drum 5 having a surface potential of 800 mm, and when each was rotated in the direction of the arrow in the figure, the developer was transferred to the photosensitive drum. It was transferred to the surface and good development was performed.

Figure 2 shows the adhesion of toner particles formed on the surface of the developing roll and the amount of triboelectric charge that the toner acquires when the pressure contact force of the blade is changed under the setting conditions shown in Figure 1. These are experimental results showing how the change occurs. As can be seen from the figure, when the contact mode of the blade is a line contact, that is, when the edge of the grade is brought into contact with the developing roll, the surface of the developing roll changes in response to minute changes in the grade pressure P. Since the toner adhesion amount m varies greatly, a problem arises in that setting conditions must be strictly maintained in order to maintain m at a constant value.

On the other hand, when the contact mode is full-surface j contact, the change in toner applied layer j4 (' rn with respect to the change in grade pressure is gradual C, therefore, toner 1 = J after 1.i m
It can be seen that it is relatively easy to maintain a constant value. Also, from the same figure, regarding Toner's dark side, Le Emperor's death,
It can be seen that the surface contact method is superior to the line contact method. That is, even under the same pressure of 11'M, when surface contact is made, a larger toner energy -Fjj is produced.

FIG. 3 shows experimental results that more clearly demonstrate the superiority of the surface contact method regarding toner charging ff, f. Toner band 'ton' U4 ((μ
0/g), the amount of toner band 'α for the same toner adhesion body is a large value in the case of surface contact method, tn = 0.4 <mg/cnt"
), the amount of charge obtained by the surface contact method is approximately 3 times that obtained by the line contact method. Therefore, when using non-contact type development as shown in Fig. 1, it is not possible to form a single layer of toner using the surface contact method. This has the effect of making transfer possible and easing the strictness of the mechanical precision required when setting this gap. 9. Figure 4 shows that development is carried out using the structures () and f in Figure 1. , shows the results of measuring the image I# degree by transferring this onto plain paper. In this case as well, the line contact method fails to provide sufficient density for both images, and is found to be inferior to the surface contact method.

FIGS. 5 and 6 are schematic diagrams showing the contact portion between the blade and the developing roll. When the contact state is as shown in FIG. 5, the contact area between the surface of the current 1y roll 6 and the rubber blade 7 is large, so it is thought that pressure unevenness is dispersed and a uniform layer of toner is formed. Furthermore, since the angle formed between the surface of the developing roll 60 and the rubber blade 7 is small, the distance between the two changes gradually until it reaches the contact area.
During this time, it is thought that the toner will be further organized and uniformed. Furthermore, in the contact area, since the nip width between the two is large, the toner is not subjected to friction under pressure for a long time, which promotes the charging of the toner, and the individual toner particles are captured +rJ'Itp (!). +J' and Lll become more uniform.

In contrast to these advantages of the surface contact method, the line contact method shown in FIG. 6 has the following drawbacks. Firstly, since the pressure contact force is concentrated on the edge, the effect of regulating the passage of toner becomes excessive, and the toner layer λ゛t1□) that is formed tends to become too small. Second, because the angle between the developing roll 9 and Grade 10 is large, the toner layer cannot be sufficiently organized and homogenized before reaching the contact area, and thirdly, the toner layer may have irregularities in output force. The nip width is small in Q11J4, so the frictional charging of the toner is insufficient and uneven. Fifthly, the grade is easily worn out in 15 minutes. There are many problems such as the fact that IA6 is easily affected by impurities such as dust mixed into the toner layer.

As mentioned above, for the purpose of forming a uniform thin layer of toner and uniformly and sufficiently charging the toner, the grade's surface contact method is used in many respects, and this method allows for good performance using a single-component developer. A JJL image can be performed.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view showing an embodiment of the present invention device 1, and Fig. 2 shows the surface of the developing roll when the pressure contact force of the grade is changed under the setting conditions shown in Fig. 1. Figure 3 is a curve diagram of experimental results showing how the amount of toner adhesion formed in a single layer and the j7:friction zone '#JL charge meter changes. Figure 4 is a curve diagram of the experimental results showing the relationship between blade pressure and image density. Figure 5 is a curve diagram of the experimental results showing the relationship between blade pressure and image density. Figure 5 is when the contact mode between the blade and the developing roll is surface contact. 1.>I, Figure 6 is an enlarged cross-sectional view of the contact area when the contact mode between the grade and the developing roll is line contact. 1: Developing roll (developer agent carrier) 2: Rubber blade (flexible gold powder member). 3: Toner (-component developer) 6: Current roll. 7: Rubber blade, 8: Toner. 9: Developing roll, 10: Rubber blade. 11: Toner. S - . Proxy ノP り± iJ'J ＞!f +tt:
, BA1 (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] a movable developer carrier that carries and conveys a monocomponent developer made of only magnetic or non-magnetic toner on its surface; a developer supply device that supplies the monocomponent developer to the movable developer carrier; In a developing device fM having a flexible powder coating member of the developer carrier pressed against the surface of the developer carrier, a contact mode between the flexible powder coating member and the movable developer carrier is surface contact. An electrostatic latent image developing device characterized in that, and an end portion of the flexible powder coating portion does not come into contact with the developer carrier.