JPH07209985A - Developing device and recording device using the same - Google Patents

Abstract

PURPOSE:To always realize stable development by correcting the irregularity of developing density and one-sided thinning in a developing device. CONSTITUTION:A blade 2 is supported in a rotary frame 14 through a blade stay 9. Furthermore, a supporting shaft 5 is fixed on the upper surface of the frame 14, and the frame 14 is attached to a main body frame 17 so that the frame 14 can be rotated around the supporting shaft 15 with respect to the main body frame 17. When the blade 2 is pressed to a developing roller 1 by such constitution, the blade 2 is automatically turned in a direction where load distribution is uniformly dispersed with respect to the pressing part in the longitudinal direction of the roller 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic device, an electrostatic recording device and the like, and more particularly to a developing device for visualizing an electrostatic latent image used in those devices.

[0002]

2. Description of the Related Art As a conventional developing technique, a pressure developing method as shown in FIG. 6 is known as a one-component non-magnetic developing method. The developing roller 1 is arranged so as to face the photoconductor drum 6 and be spaced at a constant interval g.

A blade 2 is arranged facing the developing roller 1, and a toner supply roller 3 is arranged facing the developing roller 1. The one-component non-magnetic developer 5 (hereinafter referred to as toner) that has entered the toner hopper 8 is carried in the direction of arrow A by the toner supply roller 3 and is pumped up to the developing roller 1 to
And the blade 2 pressed against the developing roller 1. Here, the toner 5 is charged by the friction between the two, and at the same time, is made thin by the pressure of the blade 2 and is sent out to the photosensitive drum 6 side.

At this time, since the bias voltage is applied to the developing roller 1, the toner 5 is directed toward the electrostatic latent image on the photoconductor drum 6 facing the developing roller 1 and the photoconductor at a minute interval. Flies and the electrostatic latent image is visualized.
The toner 5 remaining on the developing roller 1 without flying.
After being collected by the recovery blade 7, the toner is scraped off the developing roller 1 by the toner supply roller 3. Then, it is configured to return to the toner hopper 8 in the container 4 after passing below the toner supply roller 3.

Therefore, in the conventional developing device, as shown in FIG. 6, the blade stay 9 for holding the blade 2 is rotatably held around the support shaft 10 and the blade stay 9 is pushed by the adjusting screw 11. The pressing force of the blade 2 is adjusted by rotationally displacing it.

For example, Japanese Patent Laid-Open No. 4-80774 discloses such a conventional structure. FIG. 5 shows the pressing force of the layer forming member and the developing density (OD value: Opticity).
It is a graph which shows the relationship of (value). The pressing force of the layer forming member is a factor that greatly contributes to the development density, and the pressing force and the development density have a monotonically decreasing relationship. Therefore, if the pressing force of the layer forming member is non-uniform, the development density is also non-uniform.
At this time, the pressing force indicates the load per contact length between the layer forming member and the developer holder.

[0007]

However, when the above structure is used, there are the following problems. (1) Due to the component tolerance, the layer forming member is inclined with respect to the developer holder. Therefore, the parallelism of the layer forming member with respect to the axial direction of the developer carrying member cannot be guaranteed. (2) Since the parallelism of the layer forming member with respect to the axial direction of the developer carrying member cannot be guaranteed, the pressing force of the layer forming member against the developer holding member becomes non-uniform, resulting in uneven development density and blurring on one side. (3) Since the inclination of the layer forming member with respect to the developer holder cannot be adjusted from the outside, unevenness in development density and blurring on one side cannot be corrected.

(4) High quality recorded images cannot be obtained with a recording apparatus using a developing device which causes uneven development density and blurring on one side.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device capable of correcting unevenness in developing density and blurring on one side, and always obtaining stable development, in order to solve such a conventional problem. Still another object of the present invention is to provide a recording apparatus capable of obtaining a high quality recorded image.

[0010]

In order to solve the above-mentioned problems, a developing device of the present invention forms a developer layer on a developer holding member by pressing a layer forming member against the developer holding member. In a developing device that develops a developer layer by facing an electrostatic latent image formed on an image bearing member, the developing device includes a layer forming member and a holding member that directly or indirectly holds the layer forming member. The member is supported so as to be rotatable about an axis parallel to the pressing surface of the layer forming member and perpendicular to the rotation axis of the developer holder.

Further, in the recording apparatus of the present invention, an electrostatic latent image is formed by exposing the image carrier, charging means for charging the image carrier, and the image carrier charged with a signal corresponding to a desired image. An exposure unit for forming a latent image; a developing device according to claim 1 for developing the electrostatic latent image on the image carrier to obtain a visible image; and a visible image obtained by the developing device. The transfer unit for transferring to the transfer medium, the discharging unit for discharging the charged image carrier after the transfer, and the cleaning unit for removing the developer remaining on the image carrier are provided.

[0012]

In the developing device configured as described above,
When the layer forming member presses the developer holder, the layer forming member rotates in a direction such that the load distribution is uniformly dispersed with respect to the pressing portion in the longitudinal direction of the developer holder. That is, the layer forming member is in a state of always maintaining parallelism with the developer holding member.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the configuration of a developing device in one embodiment of the present invention. The developing roller 1 as a developer carrying member is 150 to 300 μm in opposition to the photoconductor drum 6.
They are arranged with a minute gap g of about a certain degree, and rotate in the direction of arrow A. The developing roller 1 is made of a conductive material such as aluminum, stainless steel, carbon steel, and conductive rubber. Aluminum is particularly preferable because of its workability and weight reduction. Then, the developing roller 1 is subjected to surface roughening processing such as sandblasting so that the toner 5 easily adheres to the surface thereof.
Further, if the material has a low hardness, it is preferable to perform surface treatment such as nickel plating. At this time, the appropriate surface roughness of the developing roller 1 varies depending on the size of the toner 5, but if the toner particle size is around 10 μm, it is preferably about 2 to 6 μmRz.

A blade 2 as a layer forming member is arranged facing the developing roller 1, and its free end is arranged in a direction opposite to the rotating direction of the developing roller 1 (direction of arrow A). The length L of the free end of the blade 2 serves to limit the amount of the toner 5 that intervenes between the developing roller 1 and the blade 2, and preferably 1
Set to ~ 3 mm. Since the toner 5 is rubbed between the blade 2 and the developing roller 1 and charged, the material of the blade 2 is determined by the physical property value of the toner 5. In the present embodiment, since the toner is negatively charged, the toner 5 is selected to be negatively charged, and the blade 2 is selected to a material that causes the toner 5 to be negatively charged by friction. The blade 2 is a block or a flat plate, but a flat plate having elasticity and a low spring constant is preferable in order to absorb the undulation of the surface facing the developing roller 1. Therefore, the blade 2 is preferably made of a leaf spring material having a thickness of about 0.1 to 0.3 mm, such as phosphor bronze or beryllium copper.
Further, in order to form a uniform toner layer, it is desirable to regulate the flatness of the blade 2 to 100 μm or less.

A toner supply roller 3 is provided at a position upstream of the blade 2 in the rotational direction of the developing roller 1 so as to face the developing roller 1 and rotates in the same direction as the developing roller 1. The roller portion of the toner supply roller 3 is a sponge-like foam material, and the toner is supplied to the bubble portion to supply the toner 5. The number of bubbles in the roller portion of the toner supply roller 3 is about 30 to 80 pieces / 25 mm. Further, the toner supply roller 3 is preferably set in a state of being pressed against the developing roller 1 by a contact depth of 0.5 mm or more.

An agitator 12 is provided behind the toner supply roller 3 and has a structure in which a flat plate material such as a PET film is attached to the rotary shaft. Then, by rotating in the same direction as the developing roller 1, the toner hopper 8
The toner inside is stirred and the toner 5 is supplied to the toner supply roller 3.

Since the developing process for this developing device is shown in the conventional example, it is omitted here. FIG. 2 is an exploded perspective view showing the configuration of the blade unit 20 in this embodiment,
FIG. 3 is a sectional view showing a mounting state of the rotary frame 14 and the main body frame 17 in this embodiment.

The blade 2 has its fixed end fixed to the D surface of the blade stay 9. The fixing method is, for example, adhesion, screw fastening, chucking or the like, and screw fastening is preferable for securely fixing the blade 2. In this embodiment, the blade 2 is fixed by being sandwiched between the blade stay 9 and the blade cover 4 and fastened by the set screw 19. It is preferable to regulate the flatness of the D surface as much as possible so that the waviness of the D surface of the blade stay 9 does not affect the blade 2.

A support shaft 10 is fixed to both ends of the blade stay 9 in the longitudinal direction in the axial direction of the developing roller 1. As a method of fixing, for example, press fitting, caulking,
Adhesion, screw fastening, etc. are available, but any method may be used as long as the strength can be secured. Here, insertion holes having a diameter larger than the diameter of the support shaft 10 are provided at both ends in the longitudinal direction of the rotary frame 14 as a holding member in the axial direction of the developing roller 1. The support shaft 10 is inserted into the insertion hole via a bush (not shown). With such a structure, the blade stay 9 is rotatably supported with respect to the rotating frame 14 about the support shaft 10 as a rotation center.

Further, the rotary frame 14 has a support shaft 15 fixed to the center of the G surface in the longitudinal direction. The fixing method is the same as that of the support shaft 10. Here, as shown in FIG. 3, the main body frame 17 is provided with an insertion hole having a diameter larger than that of the support shaft 15. A female screw is formed on the upper portion of the support shaft 15 in the axial direction. After the support shaft 15 is inserted into the insertion hole through the bearing 16, the support shaft 15 is fastened from above the support shaft 15 with a set screw 18. At this time, the screw head of the set screw 18 is larger than the outer diameter of the support shaft 15. With such a structure, the rotary frame 14 is rotatably supported with respect to the main body frame 17 about the support shaft 15 as a rotation center.

Further, the elastic body is arranged so as to be sandwiched between the E surface of the rotary frame 14 and the F surface of the blade stay 9.
A spring or rubber is used as the elastic body, and a compression coil spring is preferable as the spring because the load can be easily managed. In this embodiment, the compression coil spring 13 is used. With such a structure, the blade stay 9 is rotationally displaced together with the blade 2 in the arrow B direction in FIG.

Therefore, the load determined by the displacement amount of the compression coil spring 13 and the spring constant is transmitted as a pressing force to the contact portion between the blade 2 and the developing roller 1 via the mechanism of the rotational displacement. The operation of the blade unit 20 configured as above will be described below.

FIG. 4 is an explanatory diagram showing the operation of this embodiment. The blade 2 is the developing roller 1 as shown by the solid line.
When pressing the peripheral surface of the developing roller 1, one of the blades 2 in the longitudinal direction (the left side in FIG. 4) first contacts the developing roller 1. Therefore, if the blade 2 presses the developing roller 1 in this state, the pressing force increases due to the concentration of the load by the compression coil spring 13 on the side that hits first, and the blade pressing force and the developing density shown in FIG. From the relationship, the development density is lower on the left side. On the other hand, in the case of a bad hit, the pressing force becomes low and the developing density rises, or the pressing force is insufficient to cause excessive toner spillage, causing phenomena such as fogging and toner scattering inside the device. .

However, with the structure of the blade unit as described above, the blade 2 is rotationally displaced to the position shown by the broken line by the rotation of the rotary frame 14, and the applied load is automatically dispersed on the developing roller 1. , Try to keep the load distribution in the longitudinal direction balanced. Therefore, the distribution of the pressing force is made uniform, and a thin toner layer having a uniform layer thickness and a uniform charge amount is formed on the developing roller 1, and stable development is performed.

In the present embodiment, the member that is parallel to the pressing surface of the blade 2 and is rotatable around the axis of the developing roller 1 is the rotating frame 14.
Since No. 4 holds the blade 2 via the blade stay 9, it can be said to be indirectly held.

Further, the support shaft 15 is fixed to the F surface of the blade stay 9 in the same manner as described above, and the blade stay 9 is fixed to the main body frame 17 or other members so as to be rotatable around the support shaft 15. If so, the member that is parallel to the pressing surface of the blade 2 and rotatable about the axis of the developing roller 1 is the blade stay 9, and it can be said that the blade stay 9 directly holds the blade 2. Therefore, even with such a configuration, the same operation and effect can be obtained.

Further, in this embodiment, the blade stay 9
The blade 2 was pressed against the developing roller 1 by rotationally displacing the blade. However, the present invention is not limited to this method, and for example, the blade stay 9 is directly displaced to press the blade 2 against the developing roller 1. However, the same effect can be obtained.

Next, an embodiment of a color image recording apparatus using the developing device of the present invention will be described with reference to FIG. Figure 7
In the color image recording apparatus, a charging device 102, an exposure device 103, a first developing device 104, and a second developing device 104 are provided around a photoconductor drum 101 having an electrophotographic photosensitive layer formed on the surface thereof.
The developing device 105, the third developing device 106, the transfer medium winding drum 107 for winding the transfer medium 110 on which the final image is formed, the charge eliminating device 108, and the cleaning device 109 are arranged. Each operation is controlled by the control signal 122 output from the main controller 121. In this embodiment, three developing devices of the present invention described above are used to record a color image.

The transfer medium 110 includes paper feed mechanisms 111, 1
It is supplied to the transfer medium winding drum 107 that rotates in the Y direction by 12 and is wound around the transfer medium winding drum 107 by the winding roller 113.
Then, in the transfer section T, the transferred medium 110 for which each color has been transferred is sent to the fixing device 114.

The photosensitive drum 101 rotates in the direction of arrow X, and a latent image is formed by a latent image forming means composed of a charging device 102 and an exposure device 103, and a developing device 104,
A visible image is formed by one of 105 and 106, and the visible image is transferred onto the transfer medium 110 at the transfer portion T.
The photoconductor drum 101 after the transfer is finished
Then, the cleaning device 109 removes the remaining visible image forming substance.

The exposure device 103 is composed of, for example, a semiconductor laser, a polygon mirror, an fθ lens, etc., and scans the photosensitive drum 101 with a laser beam modulated based on a drive signal 140 corresponding to image data. The developing devices 104, 105, and 106 are the developing devices of the present invention, and all form a visible image with a visible image forming substance that colors the electrostatic latent image on the photosensitive drum 101. The plurality of developing devices develop with visible image forming substances of different colors, and usually yellow, magenta and cyan are used.

The fixing device 114 is composed of a roller having a heat generating portion and heat-fixes the visible image forming substance on the transfer medium 110. Next, the operation of the color image recording apparatus will be described. To simplify the description, the transfer medium 110 is supplied to the transfer medium winding drum 107 that rotates in the arrow Y direction by the sheet feeding mechanisms 111 and 112, and is already wound around the transfer medium winding drum 107 by the winding roller 113. It is supposed to be.

When the data corresponding to the color signal of the yellow surface is prepared, the photosensitive drum 101 is charged by the charging device 102. The data corresponding to the color signal of the yellow surface is the drive signal 140 for modulating the laser beam.
And is input to the exposure device 103, modulation of the beam corresponding to the color signal of the yellow surface is started, and the modulated laser beam scans the photoconductor 101. A latent image corresponding to yellow is formed on the peripheral surface of the photosensitive drum 101 by the main scanning by the laser beam and the sub-scanning by the rotation of the photosensitive drum 101. The latent image is developed and visualized in the first developing device 104 with a yellow visible image forming substance. The obtained visible image is transferred to the transfer medium 110 wound around the transfer medium winding drum 107 at the transfer portion T. After the visible image is transferred by the visible image forming substance, the charge removing device 108 removes the residual charges from the photosensitive drum 101, and the cleaning device 109 removes the visible image forming substance that is not completely transferred. It is cleaned and prepared for the next latent image formation.

When the yellow image forming cycle ends in this way, the main controller section (not shown) instructs the main controller 121 to perform a magenta image forming cycle. In the magenta image forming cycle, when the data for the color signal of the magenta surface is prepared, the photosensitive drum 101 is charged again by the charging device 102. Data corresponding to the color signal of the magenta surface is converted into a drive signal 140 for modulating the laser beam, and the exposure apparatus 1
03, and writing to the photosensitive drum 101 is performed in the same manner as in the case of the color signal of the yellow surface described above to form a latent image. The latent image is developed and visualized in the second developing device 105 by a magenta visible image forming substance. The obtained visible image is transferred at the transfer portion T onto the already formed yellow visible image of the transfer medium 110 wound around the transfer medium winding drum 107. After the visible image is transferred by the visible image forming substance, the charge removing device 108 removes the residual charges from the photosensitive drum 101, and the cleaning device 109 removes the visible image forming substance that is not completely transferred. It is cleaned and prepared for the next latent image formation.

The next cyan image formation cycle is also yellow,
Similar to the case of magenta, for the color signal of the cyan surface,
Exposure, development, and transfer are performed, and a visible image is formed on the transfer medium 110 by the visible image forming substance of cyan. Here, the development is performed by the third developing device 106. In addition, as with the case of yellow and magenta, the photosensitive drum 101 is subjected to static elimination and cleaning after transfer.

The color image formed on the transfer medium 110 in this manner is sent to the fixing device 114 and fixed therein, and becomes a final color image. In the above description, charging is performed after the data for the color signal is prepared, but it goes without saying that charging may be performed in advance. Further, the case where three developing devices of yellow, magenta and cyan are used has been described, but the case of further containing black can be similarly implemented by adding another developing device. Of course, it is also possible to configure a monochromatic recording device, and in this case, only one developing device is required. Further, although both the photosensitive drum and the transfer medium winding drum are drum-shaped, it is also possible to implement either one or both belt-shaped. Furthermore, although the exposure apparatus is composed of a semiconductor laser, a polygon mirror, an fθ lens and the like, it may be composed of other means such as an LED array.

Since the developing device of the present invention using the developing device of the present invention automatically corrects the uneven development density and the blurring on one side, the present invention provides a sufficient effect even when applied to a monochromatic recording device. However, the effect is more remarkable when applied to a color recording apparatus that superposes colors.

[0038]

As described above, according to the present invention, the layer forming member is pressed against the developer holding member to form the developer layer on the developer holding member, and the developer layer is formed on the image bearing member. In a developing device that develops by facing the electrostatic latent image, it is composed of a layer forming member and a holding member that directly or indirectly holds the layer forming member, and the holding member is parallel to the pressing surface of the layer forming member. In addition, since it is configured to be supported rotatably around an axis perpendicular to the rotation axis of the developer holder, uniform pressing can be obtained over the entire width in the longitudinal direction of the developer holder. There is an effect that blurring is automatically corrected and stable development can always be achieved.

Further, in the recording device using the developing device of the present invention, a stable visible image is formed in the developing process, so that the final recorded image on the transfer medium has higher image quality. be able to.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a developing device according to the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a blade unit of the developing device according to the present invention.

FIG. 3 is a cross-sectional view showing an attached state of a rotary frame and a main body frame of the developing device in the present invention.

FIG. 4 is an explanatory diagram showing a blade operation in the developing device of the present invention.

FIG. 5 is a graph showing the relationship between the pressing force of the blade and the development density.

FIG. 6 is a side view showing a configuration of a conventional developing device.

FIG. 7 is an explanatory diagram showing a configuration of a recording apparatus according to the present invention.

[Explanation of symbols]

 101 Photoreceptor Drum 102 Charging Device 103 Exposure Device 104, 105, 106 Developing Device 108 Gradual Charge Device 109 Cleaning Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shino Koiwa 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd.

Claims (2)

[Claims] 1. A developer holding member is pressed against a layer forming member to form a developer layer on the developer holding member, and the developer layer is made to face the electrostatic latent image formed on the image bearing member. In a developing device for developing, a layer forming member and a holding member for holding the layer forming member directly or indirectly are provided, and the holding member is parallel to the pressing surface of the layer forming member and the developer holding body. A developing device, which is rotatably supported about an axis perpendicular to the rotation axis of the developing device. 2. An image carrier, charging means for charging the image carrier, and exposure means for exposing the image carrier charged with a signal corresponding to a desired image to form an electrostatic latent image. The developing device according to claim 1, wherein the electrostatic latent image on the image carrier is developed to obtain a visible image, and a transfer unit for transferring the visible image obtained by the developing device to a transfer medium. A recording apparatus, comprising: a discharging unit that discharges the charged image bearing member after transfer; and a cleaning unit that removes the developer remaining on the image bearing member.