JP2001255737A - Developer layer forming member and developing device utilizing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer layer restricting member where an even thin layer of developer can be formed with a simple constitution over a long period of time and generation of image deterioration such as white stripes can be surely prevented and a developing device utilizing it. SOLUTION: In the developer layer forming member that is in a pressurized contact with a surface of a developer carrier which is rotated and driven in a state where the developer is carried, the thin layer of the developer is formed on a surface of the developer carrier and the developer electrified, it is constituted so that a low repulsion member is utilized in at least in one part of the developer forming member part where it is in the pressurized contact with the developer carrier surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer layer forming member used in an image forming apparatus such as a copying machine, a printer, a facsimile or the like using an electrophotographic system or an electrostatic recording system.
More specifically, the present invention relates to a developer layer forming member for forming a non-magnetic one-component type developer layer, and a developing device using the same. It concerns the device.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine, a printer, a facsimile or the like using an electrophotographic system or an electrostatic recording system of this type performs image exposure on a photosensitive drum,
Forming an electrostatic latent image according to image information, visualizing this electrostatic latent image with a developing device, and transferring and fixing the visualized toner image on a transfer material to form an image It is configured to be.

In such an image forming apparatus, a one-component developer containing no carrier is used as a developer, and an electrostatic latent on the surface of the photosensitive drum is used in order to reduce the size and cost of the apparatus and to consider the environment. A one-component developing device for visualizing an image, that is, developing the image, is often used.

As shown in FIG. 12, a developing device 100 stores a toner 102 as a one-component developer in a device housing 101, and
The toner 102 is supplied to the surface of the developing roll 105 via the supply roll 104 while the toner 102 in the toner cartridge 01 is stirred by the stirrer 103. Then, the developing device 100
Represents the toner 102 supplied to the surface of the developing roll 105
Is regulated to a predetermined layer thickness by the developer layer forming member 106 and is triboelectrically charged, regulated to the predetermined layer thickness,
Further, the toner 102 that has been triboelectrically charged is
Is transported to a development area facing the photoconductor drum 107 with the rotation of the photoconductor drum 107, and the electrostatic latent image formed on the surface of the photoconductor drum 107 is developed.

When such a developing device is used, as a layer forming / charging means for forming a layer of a developer and charging on a developer carrying member carrying a non-magnetic one-component developer, Japanese Patent Application Laid-Open No. As described in Japanese Patent No. 279283, a metal layer forming blade that is pressed and rubbed against a developer carrying member is generally used. Further, as described in JP-A-4-86852, means for pressing and rubbing an elastic member having a convex cross section on a developer carrying member by a layer forming blade provided on a part of a metal blade. Etc. have also been proposed.

[0006]

However, the above-mentioned prior art has the following problems. That is, in a conventional one-component developing device, when a metal layer forming blade is used, the nip amount at the contact portion of the developer carrier is small, and it is difficult to form a uniform layer. There was a problem. In addition, when a layer forming blade in which an elastic member having a convex cross section is provided on a part of a metal blade is used, the nip width of the contact portion with the developer carrier can be increased. However, there has been a problem that the contact pressure in the nip is locally increased, so that the toner is likely to be fixed on the blade, which causes white streaks and the like, resulting in deterioration of image quality. Also,
When the contact pressure in the nip is locally increased, there is a problem that the developer is deteriorated and it is difficult to use the nip for a long time.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to form a uniform thin developer layer over a long period with a simple structure. It is an object of the present invention to provide a developer layer regulating member capable of reliably preventing image quality deterioration such as white streaks, and a developing device using the same.

[0008]

According to an aspect of the present invention, there is provided an image forming apparatus, comprising: A thin layer of developer is formed on the surface of the developer carrier, and at least a part of a portion of the developer layer forming member that comes into pressure contact with the developer carrier surface in the developer layer forming member that charges the developer. And a developer layer forming member using a low resilience member.

Further, in the invention described in claim 2, a sample of φ50 mm is compressed at a compression rate of 1 at least at a part of the portion of the developer layer forming member which is pressed against the surface of the developer carrier.
The 25% compression load when pressed at mm / min is 0.6kg
/ Cm ² or less and 50% according to JIS K6401
It is a low resilience member which is left in an environment of 70 ° C. in a compressed state for 22 hours and then released in a compressed state and changes in thickness of 3.0% or less after a lapse of 30 minutes. Item 2. The developer layer forming member according to Item 1.

Further, according to a third aspect of the present invention, a developer layer regulating member is pressed against the surface of a developer carrier which is rotated while the developer is carried thereon, and the surface of the developer carrier is contacted. In a developing device that forms a thin layer of the developer on the surface and performs development by charging the developer, at least a part of the portion of the developer layer forming member that is in pressure contact with the surface of the developer carrier has low repulsion. A developing device using a conductive member.

[0011] Still further, the invention described in claim 4 is:
When a sample of φ50 mm is pressed at a compression speed of 1 mm / min against at least a part of a portion of the developer layer forming member which is pressed against the surface of the developer carrier, a 25% compression load is 0.6%.
kg / cm ² or less and according to JIS K6401;
It is a low resilience member which is left in an environment of 70 ° C. in a state of being compressed at 50% for 22 hours and then released for 30 minutes after the compressed state is released and a change in thickness of 3.0% or less after 30 minutes. 4. The developing device according to claim 3, wherein:

[0012]

According to the above technical means, a low resilience member is used for at least a part of the portion of the developer layer forming member which is in pressure contact with the surface of the developer carrying member. Without this, a good nip width can be formed at a low linear pressure, and the contact pressure in the nip can be made substantially constant, so that a thin layer of developer that is stable for a long period of time can be formed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 shows an image forming apparatus to which a developing device according to Embodiment 1 of the present invention is applied.

In FIG. 2, reference numeral 1 denotes a photosensitive drum as an electrostatic latent image carrier.
For example, a member having a photoconductor layer made of OPC (organic photoconductor) is used. The photosensitive drum 1
Is uniformly charged to, for example, a predetermined potential of negative polarity by a charging roll 2 as a primary charging unit, and then the image is exposed to light by a laser exposure device or the like (not shown).
And an electrostatic latent image corresponding to the image information is formed. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing device 4 according to Embodiment 1 of the present invention to become a toner image, and the toner image formed on the photosensitive drum 1 is The image is transferred onto a transfer sheet 6 as a transfer material by a transfer roll 5. Transfer paper 6 on which the toner image has been transferred
Is separated from the surface of the photosensitive drum 1 and then conveyed to a fixing device (not shown), where the toner image is fixed on the transfer paper 6 by heat and pressure by the fixing device, and is discharged outside the device. It is discharged on a tray.

Incidentally, the cleaning device 7 removes residual toner from the surface of the photosensitive drum 1 after the completion of the toner image transfer step, so that the surface is ready for the next image forming step.

However, in the above-described image forming apparatus, the transfer efficiency in the transfer step is made almost 100% by using a toner having a high degree of sphericity such as a polymerization toner in a developing device for forming a toner image. A so-called cleanerless image forming apparatus which does not require a cleaning device may be configured.

FIG. 1 is a block diagram showing a developing device of a non-magnetic one-component developing system according to Embodiment 1 of the present invention.

This non-magnetic one-component developing system developing device 4
As shown in FIG. 1, a device housing 10 is provided, and a large-volume portion on the back side of the device housing 10 is a toner storage container 12 for storing a toner 11 as a non-magnetic one-component developer. I have. A developing roll 13 as a developer carrier is rotatably arranged at a predetermined speed at a position facing the photosensitive drum 1 of the apparatus housing 10. The developing roll 13 is disposed close to the surface of the photosensitive drum 1 as an electrostatic latent image carrier, and supplies toner to the electrostatic latent image on the photosensitive drum 1 to form a visible image. I do.

A supply roll 15 is arranged on the downstream side of the development region 14 in the rotation direction of the development roll 13 so as to be close to or in contact with the supply roll 15. Part of the toner supplied to the developing roll 13 by the supply roll 15 adheres to the surface of the developing roll 13 by electrostatic force or non-electrostatic adhesive force. In this way, the supply roll 15 is
In the case where the toner is supplied to the developing roll 3 and the supply roll 15 is in contact with the developing roll 13, the toner on the developing roll 13 after development is scraped to eliminate the history. Further, on the back side of the supply roll 15, while stirring the toner 11 in the toner container 12,
A paddle 16 for feeding the toner 11 to the supply roll 15 is arranged to rotate at a predetermined timing.

On the other hand, the toner 11 supplied to the developing roll 13 by the supply roll 15 is further subjected to a developing roll 13 by a layer forming blade 17 as a developer layer regulating member.
The toner 11 is frictionally charged to a predetermined polarity and charge amount by the frictional force generated by the contact between the layer forming blade 17 and the developing roll 13 via the toner layer, while the toner 11 is uniformly leveled. I have.

In this embodiment, as shown in FIG. 1, the pressure of the toner 11 stored in the toner container 12 is adjusted so that the pressure of the toner 11 does not excessively act on the layer forming blade 17. A partition member 18 is provided between the inside and the layer forming blade 17 so as to hang from the ceiling. The lower end of the partition member 18 is located, for example, slightly below a linear extension L connecting the photosensitive drum 1 and the center of the developing roll 13.

In the first embodiment, a low resilience member is used for at least a part of the portion of the developer layer forming member that is pressed against the surface of the developer carrier.

In the first embodiment, a sample having a diameter of 50 mm is compressed at a compression rate of 1 mm / at least on a part of the developer layer forming member which is pressed against the surface of the developer carrier.
25% compression load when pressed in minutes is 0.6kg / cm
² or less and according to JIS K 6401, left in an environment of 70 ° C. for 22 hours in a state of 50% compression, and then released the compressed state, and the change in thickness after 30 minutes passed.
It is configured to use a low resilience member of 0% or less.

FIG. 3 shows a layer forming blade according to the first embodiment.

As shown in FIG. 3, the layer forming blade 17 is fixed to a plate member 19 having a base end 19a attached to the apparatus housing 10 and a distal end 19b of the plate member 19, and And a contact member 20 that contacts the surface. The plate member 19 holding the contact member 20 is made of a metal having a spring property such as stainless steel or phosphor bronze, and is set to have a spring property so as to press the contact member 20 against the surface of the developing roll 13 with a desired pressure. ing.

As for the material used for the contact member 20, as shown in FIG. 4, a sample of φ50 mm was pressed at a compression speed of 1 mm / min from the evaluation result of the formation state of the thin toner layer and the number of prints until the generation of white streaks. 25% compression load at the time of 0.6 kg / cm ² or less and according to JIS K6401, 50% compression in a 70 ° C. environment.
It is necessary that the material has a material characteristic value of 3.0% or less in a change in thickness after 30 minutes after leaving it for 2 hours and then releasing the compressed state. In FIG. 4, ○ indicates that the target can be achieved in any state (environment, etc.), Δ indicates that some targets cannot be achieved due to changes in the state (environment, etc.), and x indicates the target can always be achieved. The cases where it cannot be achieved are indicated. The above material properties have a high density microcell,
It can be realized by using a foam having a uniform cell structure. In this embodiment, “Microcell polymer sheet PORON (trade name)” manufactured by Inoac Corporation is used as the material of the contact member. However, it is not limited to this,
Of course, other materials may be used as long as they have the above-mentioned material characteristics. Further, according to the characteristics of the non-magnetic one-component developer used, an extremely thin member made of silicon, PET, or the like may be attached to the surface of the contact member that comes into contact with the developing roll.

FIG. 5 shows SS curve data (load-deflection curve) of the low resilience member and the elastic member having no low resilience used in the present embodiment. As is clear from FIG. 5, unlike the elastic member having no low resilience, the low resilience member hardly increases the load even when the deflection rate increases, and the load substantially decreases with the increase in the deflection rate. It can be seen that it rises slightly linearly.

FIG. 6 shows the measured values of the linear pressure and the nip width when the low resilience member and the elastic member having no low resilience are used. As can be seen from the SS curve data, the low resilience member has a small load with respect to the deflection rate, so that a wide nip width can be formed at a low pressure. Further, since the amount of change in the load with respect to the change in the deflection rate is small, the pressure distribution in the nip becomes substantially constant as shown in FIG.

FIG. 8 is a graph comparing the life and layer uniformity of the low resilience member and the low hardness elastic member when the linear pressure is changed.

In this embodiment, the layer forming blade as a layer forming member is configured to be easily detachable from the developing device. Since the contact member is a member having low compression residual strain, it does not cause setting even if it is pressed against the developing roll for a long period of time. The forming member can be reused (recycled) without replacing the contact member.

As described above, in the above-described embodiment, since the abutting member 20 made of a low resilience member is used for at least a part of the portion of the image forming blade 17 which is in pressure contact with the developing roll 13, the structure is complicated. A good nip width can be formed at a low linear pressure without employing a simple structure, and the contact pressure in the nip can be made substantially constant, so that a thin layer of the developer that is stable for a long time can be formed. it can.

Embodiment 2 FIG. 9 shows another configuration example of the layer forming member. Layer forming member 17
Has a contact member 20 formed of a member having low resilience at a contact portion with the developer carrier 13. The contact member 20 is fixed to a contact member holding member 21 having no spring elasticity, and the contact member holding member 21 is arranged on the developer carrier 13 at a predetermined interval. Contact member holding member 21
Is determined by the required nip width. Since the low resilience member has low compressive residual strain, it is possible to always maintain a constant contact pressure, and there is no need to press with a metal member having spring elasticity such as stainless steel or phosphor bronze. . Therefore, the layer forming member 17 can form a uniform thin developer layer only by setting the disposition position with the developer carrier 13, and the configuration of the layer forming member 17 is simplified.

Third Embodiment FIG. 10 shows an example of a configuration in which a low resilience member is used for a developer carrier. As shown in FIG. 11, the developer carrier 13 is composed of a roller formed by covering a metal shaft 30 with a low resilience member 31. The developer carrier 13 is disposed at a position pressed against the electrostatic latent image carrier 1,
The electrostatic latent image written on the electrostatic latent image carrier 1 by the exposure device is developed into a developed image by a thin developer layer formed on the developer carrier 13. The developer carrier 13 is a roll formed of a low resilience member 31 on a metal shaft 30 and a thin layer of a material different from the low resilience member on the surface of the roll and the contact surface with the electrostatic latent image carrier. In some cases, a surface layer is formed.

When an elastic member having low resilience is used for the developer carrier 13, the contact pressure between the developer carrier 13 and the electrostatic latent image carrier 1 increases as the nip width increases. As a result, it is necessary to increase the rigidity of the developing device components such as the developer carrier 13 and the electrostatic latent image carrier 1, as well as the developing device main body. However, the use of a low resilience member makes it possible to reduce the amount of increase in the contact pressure even when the nip width is widened, so that the degree of freedom in setting the nip width can be increased without increasing the rigidity of the components. it can.

[0036]

As described above, according to the present invention,
By using a member having low resilience at the contact portion of the developer layer forming member with the developer carrier, it is possible to form a wide nip at a low linear pressure and provide a uniform developer thin layer for a long period of time. can do. Further, a reusable layer forming member can be provided by making the layer forming member easily detachable from the developing device.

Further, when the developer carrier is formed of a low resilience member, there is no need to increase the rigidity of the components constituting the developing device even when a wide nip is required, so that a lightweight and inexpensive developing device is provided. can do.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a developing device to which a developer layer forming member according to Embodiment 1 of the present invention is applied.

FIG. 2 is a configuration diagram illustrating an image forming apparatus to which the developing device according to the first embodiment of the present invention is applied;

FIG. 3 is a configuration diagram showing a developer layer forming member according to Embodiment 1 of the present invention.

FIG. 4 is a table showing experimental results.

FIG. 5 is a graph showing experimental results.

FIG. 6 is a table showing experimental results.

FIG. 7 is a schematic diagram showing a linear pressure of a layer forming blade.

FIG. 8 is a graph showing a relationship between life and layer uniformity with respect to linear pressure of a layer forming blade.

FIG. 9 is a configuration diagram showing a developing device to which a developer layer forming member according to Embodiment 2 of the present invention is applied.

FIG. 10 is a configuration diagram showing a developing device to which a developer carrier according to Embodiment 3 of the present invention is applied.

FIG. 11 is a configuration diagram showing a developer carrying member according to Embodiment 3 of the present invention.

FIG. 12 is a configuration diagram showing a developing device to which a conventional developer carrier is applied.

[Explanation of symbols]

1: photosensitive drum (electrostatic latent image carrier) 4: developing device
13: developing roll (developer carrying member), 17: layer forming blade (developer layer regulating member), 19: plate member (support member), 20: contact member.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shuichi Nishiide 2274 Hongo, Ebina-shi, Kanagawa Prefecture F-Xerox Co., Ltd. F-term (reference) 2H077 AB04 AC04 AD06 AD13 AD17 AD23 AD31 AE03 AE04 EA14 FA13 FA21 FA22

Claims (4)

[Claims] An image forming apparatus according to claim 1, wherein said developer carrier is pressed against a surface of said developer carrier which is rotationally driven while said developer is carried thereon, and a thin layer of developer is formed on said surface of said developer carrier, and said developer is charged. A developer layer forming member, wherein a low resilience member is used in at least a part of a portion of the developer layer forming member that comes into pressure contact with the surface of the developer carrier. 2. A 25% compression load of 0.6 kg / min when a φ50 mm sample is pressed at a compression speed of 1 mm / min against at least a part of a portion of the developer layer forming member which is pressed against the surface of the developer carrier. cm ² or less and JIS K6
It is a low resilience member having a thickness change of 3.0% or less after leaving for 30 minutes in an environment of 70 ° C. in a state of being compressed by 50% and then releasing the compressed state for 30 minutes in accordance with 401. The member for forming a developer layer according to claim 1, wherein: 3. A developer layer regulating member is pressed against the surface of a developer carrier that is rotated while holding the developer, and a thin layer of developer is formed on the surface of the developer carrier. In a developing device which performs development by charging the developer, a low resilience member is used in at least a part of a portion of the developer layer forming member which comes into pressure contact with a surface of a developer carrier. Developing device. 4. A 25% compression load when a φ50 mm sample is pressed at a compression speed of 1 mm / min against at least a part of a portion of the developer layer forming member which is in pressure contact with the surface of the developer carrier, is 0.6 kg / min. cm ² or less and JIS K6
It is a low resilience member having a thickness change of 3.0% or less after leaving for 30 minutes in an environment of 70 ° C. in a state of being compressed by 50% and then releasing the compressed state for 30 minutes in accordance with 401. 4. The developing device according to claim 3, wherein: