JP2003182134A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate properly securing an interval ΔLK between a toner pass control means 3 and a toner carrier 1 and to improve the quality of forming images, by specifying a parameter that influences the interval ΔLK in an imaging apparatus which images by discharging a toner 2 via the toner pass control means 3 from the toner carrier 1. <P>SOLUTION: When a radius of the toner carrier 1 is made (r), a radius of curvature of the toner pass control means 3 at a butting position Cp between a spacer 12 set on the toner pass control means 3 to butt against the toner carrier 1 and the toner carrier 1 is made R, and a contact pressure of the spacer 12 and the toner carrier 1 is made P, the relations r<R<4r and 0.005 N/mm<SP>2</SP><P<0.2 N/mm<SP>2</SP>are satisfied. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus applied to a copying machine, a facsimile machine, a printer, etc., and more particularly, it controls the flying of toner from a toner carrier to a facing member so that the toner can be applied to the facing member. It belongs to the technical field of an image forming apparatus that adheres to form an image.

[0002]

2. Description of the Related Art In recent years, with the improvement of personal computer capacity and the progress of network technology, there has been a strong demand for a printer or a copying machine having a high processing capacity capable of handling a large amount of documents and color documents. ing. However, an image forming apparatus capable of outputting a satisfactory high-quality black and white or color document and having a high processing speed is under development, and its appearance is awaited.

As one of them, there is known an image forming technique of a so-called "toner jet (registered trademark)" system in which toner is caused to fly by an action of an electric field onto an image receiving means such as a recording paper or an intermediate image carrying belt to form an image. Has been.

As an image forming apparatus of that kind, Japanese Patent Publication No.
4-263333 and U.S. Pat. No. 3,689,935.
There are known ones disclosed in Japanese Patent Publication No. 60-20747 and Japanese Patent Publication No. 9-500842. As an example, Japanese Patent Application No. 10-100780
What was disclosed in No. 1 will be described with reference to FIG.

In FIG. 13, 31 is a grounded toner carrier for carrying and carrying charged toner, and 32 is a regulating blade for controlling the toner on the toner carrier 31 to 1 to 3 layers and further charging. . A supply roller 33 supplies toner to the toner carrier 31 and charges the toner. Reference numeral 34 denotes a toner passage control means, which is the toner passage hole 3
5 is formed, and the control electrode 36 is arranged around it. A voltage corresponding to an image signal is applied from the control power supply 37 to the control electrode 36. 38 is a back electrode, 39
Is the back electrode power supply. Reference numeral 40 is an image receiving means such as a recording paper conveyed on the back electrode 38.

In the above-mentioned structure, by operating the supply roller 33 and the toner carrier 31, the regulating blade 32 forms a uniform toner layer on the toner carrier 31 and conveys the back electrode. Applying voltage to 38,
When the voltage corresponding to the image signal is applied to the control electrode 36 by the control power source 37 such as the driving IC in synchronization with the movement of the image receiving means 40, the toner on the toner carrier 31 responds to the image signal. And flies onto the image receiving means 40 through the toner passage hole 35 and adheres thereto, and a desired image is formed on the image receiving means 40.

On the entire surface of the image receiving means 40, for example, 6
In order to form a fine image of 00 dpi (density of 600 dots per inch), it is necessary to dispose the toner passage holes 35 at such a pitch in the toner passage control means 34, which cannot be arranged in a single row. As shown in FIG. 15, the toner passage holes 35 and the control electrodes 36 are arranged in a large number of rows (8 rows in the illustrated example). The toner passage hole 35 and the control electrode 36 are circular, and the connection electrodes that are electrically connected to the respective control electrodes 36 are provided on both sides in the moving direction of the toner carrier 31 in order to avoid mutual interference, and drive ICs that output control voltages respectively. Connected to the lead.

In FIG. 13, the image receiving means 40 is made of recording paper or the like and an image is directly formed on the recording paper. However, the recording paper or the like has variations in thickness, changes in properties due to humidity, and movement. Since there is a problem in that the internal deformation easily occurs, and in the case of a color printer, it is difficult to synchronize the image forming timing of each color due to variations in recording paper conveyance, and the image quality easily deteriorates. As disclosed in No. 100780, it may be preferable to use an intermediate image bearing belt as the image receiving means 40 and to collectively transfer the images formed on the image bearing belt to a recording paper or the like. .

This will be described with reference to FIG.
Is an endless image bearing belt as the image receiving means 40, which is made of a film having a resistance of about 10 ¹⁰ Ω · cm in which a conductive filler is dispersed in a resin, and is wound between a pair of rollers 44 a and 44 b. Reference numeral 45 is a pickup roller for feeding the recording papers 46 from the paper feed tray one by one, 47 is a timing roller for synchronizing the image position with the fed recording papers 46, and 48 is a toner image formed on the image carrying belt 42. The transfer roller is a transfer roller that transfers the recording paper 46. The transfer roller is pressed toward the roller 44a with the image carrying belt 43 interposed therebetween, and a transfer voltage is applied. A fixing device 49 fixes the toner image on the recording paper 46 by heating and pressing the recording paper 46 on which the toner image is transferred.

[0010]

In the image forming apparatus as described above, the amount of toner passing through the toner passage hole is determined by the toner carrier and the control electrode at the position where the toner passage hole is arranged. The distance ΔLk from the existing toner passage control means is greatly affected. That is, when this interval ΔLk is too small, the amount of toner passing through the toner passage hole increases, causing a problem of so-called fogging in which the facing means such as the recording paper becomes dirty, while the interval ΔLk
When is too large, the amount of toner passing through the toner passage hole is reduced, and the formed image becomes thin. Therefore, in order to improve the quality of the formed image, it is necessary to properly maintain the interval ΔLk.

However, at present, the relationship between the layout condition between the toner carrier and the toner passage control means and the above-mentioned interval ΔLk has not been clarified. Therefore, it is difficult to stably maintain the appropriate interval ΔLk and improve the image quality. That is, a method of setting the above-mentioned interval ΔLk to a desired size has not been established yet, and there is room for development.

The present invention has been made in view of the above problems, and an object of the present invention is to clearly set layout conditions when a toner carrier and a toner passage control unit of an image forming apparatus are combined. The purpose is to facilitate proper and stable holding of the interval ΔLk between the toner carrier and the toner passage control means, and improve the quality of the formed image.

[0013]

In order to achieve the above-mentioned object, the inventors of the present invention have conducted extensive studies to realize a radius of curvature in the vicinity of the contact position of the toner passage control means with the toner carrier. R and the contact pressure P of the toner carrier and the toner passage control means respectively affect the interval ΔLk, and further, the radius of curvature R and the contact pressure P for making the interval ΔLk within a proper range. Each size range was found.

Specifically, according to the first aspect of the invention, a toner carrier composed of a roller for carrying and carrying toner, a facing member arranged to face the toner carrier, and the toner carrier. And a toner passage hole, which is disposed between the opposing member and allows the toner of the toner carrier to pass toward the opposing member side, has a toner passage hole array arranged parallel to the axis of the toner carrier. An image formation including a toner passage control means for controlling passage of toner through the toner passage hole based on an image signal from the outside, and a spacer provided on the toner passage control means and abutting on the toner carrier. The device is the target. When the radius of the toner carrier is r and the radius of curvature of the toner passage control means at the abutting position of the spacer and the toner carrier is R, r <R <4r. It is characterized by satisfying ‥‥‥‥‥‥‥‥‥‥‥‥‥.

If the radius of curvature R near the contact position of the toner passage control means is less than the radius r of the toner carrier (R≤
In the case of r), as shown in FIG. 11A, the toner carrier comes into contact with the toner passage control means at a position other than the contact position. Therefore, the distance ΔLk between the toner carrier and the toner passage control means at the position where the toner passage hole is arranged becomes small, and it is not possible to secure an appropriate size. Further, since the toner stays in the space defined by the toner passage control means, the spacer and the toner carrier between the two contact positions, so-called fogging occurs and the opposing member is contaminated.

On the other hand, the radius of curvature R is 4r or more (4r ≦
When it is R), as shown in FIG. 11B, the interval ΔLk becomes large and exceeds the appropriate range of the interval ΔLk. Therefore, the density of the formed image is reduced and the image quality is degraded.

Further, in the case where a plurality of toner passage hole rows are provided, the larger the radius of curvature R is set, the larger the gap between the toner passage control means and the toner carrier in each toner passage hole row is. The difference increases. Therefore, the density difference between the images formed by the respective toner passage hole arrays becomes large, resulting in density unevenness.

That is, since the interval ΔLk can be set to an appropriate size by the configuration of the present invention, the toner carrier and the toner passage control means are prevented from coming into contact with each other at a position other than the abutting position. Thus, it is possible to prevent the occurrence of fogging and to improve the image quality by appropriately adjusting the density of the formed image.

According to a second aspect of the present invention, a toner carrier that is a roller that carries and conveys toner, a facing member that is disposed to face the toner carrier, and a space between the toner carrier and the facing member. And a toner passage hole for passing the toner of the toner carrier toward the facing member side has a toner passage hole array arranged in parallel with the axis of the toner carrier, The image forming apparatus is provided with a toner passage control means for controlling the passage of the toner on the basis of an image signal from the outside, and a spacer provided on the toner passage control means and in contact with the toner carrier. . Then, the contact pressure P of the spacer and the toner carrying member, and satisfies the ^{0.005N / mm 2 <P <0.2N} / mm 2 ‥‥‥‥‥‥.

If the contact pressure P between the spacer and the toner carrier is 0.005 N / mm ² or less (P ≦ 0.005 N /
When it is mm ² ), the interval ΔLk becomes unstable, so that the density of the formed image is not stable.

On the other hand, when the contact pressure P is 0.2 N / mm ² or more (0.2 N / mm ² ≤P), the toner on the toner carrier is scraped off at the contact position, so that the toner is removed. The layer becomes thin and the density of the formed image becomes thin.

Therefore, according to the above-described structure of the present invention, the toner carrier can be brought into uniform contact with the spacer on the toner passage control means to stably secure the interval ΔLk. Furthermore, since the toner on the toner carrier can pass through the toner passage hole without being scraped by the spacer,
The density of the formed image can be made appropriate.

According to another aspect of the present invention, a toner carrier that is a roller that carries and conveys toner, a facing member that is disposed so as to face the toner carrier, and a space between the toner carrier and the facing member. And a toner passage hole for passing the toner of the toner carrier toward the facing member side has a toner passage hole array arranged in parallel with the axis of the toner carrier, The image forming apparatus is provided with a toner passage control means for controlling the passage of the toner on the basis of an image signal from the outside, and a spacer provided on the toner passage control means and in contact with the toner carrier. . When the radius of the toner carrier is r, the radius of curvature of the toner passage control means at the contact position of the spacer and the toner carrier is R, and the contact pressure of the spacer and the toner carrier is P, r <R <4r ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 0.005N / mm ² <P <0.2N / mm ² ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ And By this,
It is possible to prevent the occurrence of fogging and to stably secure the interval ΔLk to optimize the density of the formed image.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2 showing the schematic configuration of the image forming apparatus of the present embodiment, reference numeral 1 denotes a toner carrier that carries and conveys the charged toner 2, which is composed of a rotatable roller that is grounded, and the charged toner 2 is 1 It is adsorbed in a thin layer of 3 layers.

Reference numeral 3 denotes a toner passage control means, the structure of which will be described in detail later. Normally, the toner passage control means 3 is made of a flexible resin film containing a control electrode, and is made of a different material having different elastic coefficients. It is composed by. The toner passage control means 3 is supported by a fixed body such as a casing at both ends in the direction orthogonal to the toner passage hole rows 5 and 5. Specifically, as shown in FIG. 1, one end is elastically held by the elastic holding means 24, while the other end is fixedly held by the fixed holding means 14.

The elastic holding means 24 has a curved surface portion 25a formed as an R surface, and a flat surface portion continuously formed at one end of the curved surface portion 25a and extending perpendicularly to the tangential direction at one end of the curved surface portion 25a. 25b and the curved surface portion 2
An abutting portion 25 that abuts the toner passage control means 3 at 5a is provided. The shaft portion 26 extending in the direction perpendicular to the plane of the plane portion 25b of the contact portion 25 is fitted and fixed to the plane portion 25b. A spring 27 is wound around the outer peripheral surface of the shaft portion 26, and one end thereof is fixed to the flat surface portion 25b of the contact portion 25. Further, a cylinder portion 28 having a substantially bottomed cylindrical shape is provided so as to be loosely fitted to the shaft portion 26 and the spring 27. A through hole that is larger than the diameter of the shaft portion 26 and smaller than the diameter of the spring 27 is formed at the bottom of the cylinder portion 28, and the tip of the shaft portion 26 projects into this through hole. . On the other hand, on the outer peripheral surface of the cylinder portion 28, a holding portion 28a having opposing flat surfaces for holding the toner passage control means 3 is integrally formed with the cylinder portion 28.

As described above, the elastic holding means 24 is composed of the abutting portion 25, the shaft portion 26, the spring 27 and the cylinder portion 28, and one end of which passes the toner fixedly held by the fixing holding means 14 which will be described later. The other end of the control unit 3 is brought into contact with the curved surface portion 25a of the contact portion 25, and the toner passage control unit 3 is moved to the cylinder portion 2 while the spring 27 is further compressed.
It is configured to be elastically held by being sandwiched by eight holding portions 28a.

On the other hand, as shown in FIGS. 1 and 2, in the image forming apparatus according to the present embodiment, the toner passage control means 3 is
Via the spacer 12 on the toner passage control means 3,
The fixed holding means 14 is provided to hold the toner carrier 1 in contact with the contact position Cp. The fixed holding means 14 is provided with a first support portion supporting one end side of the toner passage control means 3 and a predetermined distance from the first support portion toward the contact position Cp, and the toner passage control means is provided. 3 has a second support portion that supports the contact position Cp side.

That is, as shown in FIG. 1, the fixed holding means 14 is movably arranged in a casing (not shown) of the image forming apparatus, and has a rectangular rod-shaped base extending in the axial direction of the toner carrier 1. The portion 15, the shaft portion 16 fixed to the base portion 15 in a state of penetrating the base portion 15, and arranged so as to be movable in the axial direction with respect to the shaft portion 16,
Similar to the base portion 15, a substantially plate-shaped contact portion 17 extending in the axial direction of the toner carrier 1 is provided. This contact portion 17
Has an edge receiving portion 17a formed as an R surface, and a flat surface portion 17b continuously formed at one end of the edge receiving portion 17a and extending tangentially at one end of the edge receiving portion 17a.

Further, the fixed holding means 14 has a contact portion 17
A cover portion 18 having a substantially plate shape extending along is provided. The cover portion 18 is supported by the base portion 15 by fastening both ends of the cover portion 18 and the base portion 15 in the axial direction of the toner carrier 1 with adjusting screws 19. Therefore, the adjusting screw 19 can change the distance between the cover portion 18, the base portion 15 and the contact portion 17.

The flat portion 18c of the cover portion 18 has
A block-shaped pressing member 18b provided so as to be retractable from the flat surface is provided, and the toner passage control unit 3 is held between the flat member 17b of the contact member 17 and the flat member 17b by protruding from the flat member 18c. It is designed to be held in a fixed state.

The cover portion 18 has a flat surface portion 18c and a curved portion 18d which respectively face the flat surface portion 17b and the edge receiving portion 17a of the contact portion 17, and the edge receiving portion 17a and the curved portion 18d are separated from each other. It has the same R surface.
The cover portion 18 has an edge portion 18a in which an edge is formed as a boundary between the curved surface of the curved portion 18d and a plane extending in a direction substantially perpendicular to the tangential direction of the curved portion 18d.

Thus, the flat surface portion 17b of the contact portion 17 is
And the pressing member 18b of the cover portion 18 constitute the first support portion, while the edge receiving portion 17a and the edge portion 18a.
And constitute the second support portion, and as shown in FIG.
A predetermined space is provided between the first and second support portions.

Further, the second supporting portion is formed by the edge portion 18a and the edge receiving portion 17a so that the contact portion of the toner passage control means 3 with the second supporting portion is linear and parallel to the axial center of the toner carrier 1. I support it.

In this way, the first support portions 17b, 18
While b holds the toner passage control means 3 in a fixed manner, the second supporting portions 17a and 18a support the toner passage control means 3 in a state of being bent at a predetermined angle.

In the present embodiment, as shown in FIGS. 1 and 2, the toner passage control means 3 is located on the upstream side (upper side in FIG. 1) of the toner 2 in the conveying direction in the vicinity of the toner passage hole array 4 described later. While the toner passage control means 3 is elastically held on the lower side (lower side in the figure), the toner passage control means 3 is elastically held on the upper side and fixedly held on the lower side. Good.

Reference numeral 6 denotes a back electrode which is composed of a rotatable roller and is arranged so as to face the toner carrier 1 with the toner passage control means 3 interposed therebetween. Reference numeral 7 denotes a facing member such as a recording paper or an image bearing belt which is disposed so as to face the toner carrier 1 and is conveyed in the direction of arrow a on a fixed path between the back electrode 6 and the toner passage control means 3. is there.

The toner passage control means 3 includes the toner carrier 1
Is provided with a spacer 12 having a predetermined thickness. That is, the spacer 12 is on the surface of the toner passage control means 3 facing the toner carrier 1, and includes the contact position Cp with the toner carrier 1, and from this side, the moving direction of the toner carrier 1 is on the better side. And is in contact with the toner carrier 1. As a result, the distance between the toner carrier 1 and the toner passage control means 3 is regulated by the thickness of the spacer 12 itself and maintained constant. The spacer 12 is electrically grounded and has a thickness of 5 to 20.
μm is preferable, and is 10 μm in this embodiment.

As shown in FIGS. 1 and 2, the toner passage control means 3 is disposed between the toner carrier 1 and the facing member 7, and the toner 2 of the toner carrier 1 is placed against the facing member 7.
It has a toner passage hole array 5 composed of toner passage holes 4 that pass toward the side. More specifically, the toner passage hole array 5 has the toner passage holes 4 arranged in parallel with the axis of the toner carrier 1. Then, the passage of the toner 2 through the toner passage hole 4 is controlled based on an image signal from the outside. As shown in FIG. 3, the toner passage control means 3 includes a main film 8 having a thickness of about 50 μm.
And a three-layer polyimide resin film consisting of upper and lower cover films 9a and 9b having a thickness of about 10 to 30 μm, which are attached to both surfaces thereof with an adhesive layer having a thickness of about 10 to 15 μm. Of course, the material, size, and number of constituent layers of each film are not limited to this.
It may be designed arbitrarily. Further, in the present embodiment, the toner passage hole rows 5 and 5 are located at a proper distance from the contact position Cp between the toner carrier 1 and the toner passage control means 3 to the lower side in the moving direction of the toner carrier 1. Two rows are arranged in the moving direction of the toner carrier 1.

In the figure, the control electrode 1 is provided on the upper surface of the main film 8 so as to surround each toner passage hole 4.
0 is disposed on the lower surface of the main film 8 so as to surround the toner passage hole 4 from both sides.
11b is provided. These electrodes 10, 11a, 1
1b is a pattern formed on the main film 8 8 to 2
It is composed of a Cu film having a thickness of about 0 μm.

Although the shape of the toner passage hole 4 is circular as shown in FIG. 6A, it may be oval or elliptical. Dimensionally, the diameter is set to about 70 to 120 μm. Further, the surface roughness of the inner peripheral wall surface of the toner passage hole 4 is 0.1 to less than the average particle diameter of the external additive of the toner 2.
It is set to 0.5 μm or less. Drilling with such a surface roughness can be performed by drilling with an excimer laser or press, and other YAG laser or CO.
₂ After drilling with a laser or the like, post-treatment such as etching may be performed.

The control electrode 10 around the toner passage hole 4 also preferably has a shape corresponding to the planar shape of the toner passage hole 4 as shown in FIG. 6A. Further, as shown in FIG. 6B, the deflection electrodes 11a and 11b are shared by the adjacent toner passage holes 4.

As a feature of the present invention, in the image forming apparatus according to the present embodiment, the radius of the toner carrier 1 is r, the curvature of the toner passage control means 3 at the contact position Cp of the spacer 12 and the toner carrier 1. When the radius is R and the contact pressure between the spacer 12 and the toner carrier 1 is P, r <R <4r ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 0.005N / mm ² <P <0.2 N / mm ² ···············

Specifically, the radius of curvature R at the contact position Cp of the toner passage control means 3 is, for example, three times the radius of the toner carrier 1, that is, R = 3r. Further, the contact pressure P between the spacer 12 and the toner carrier 1 is set to, for example, 0.1 N / mm ² . It should be noted that the present invention is not limited to this, and it goes without saying that the radius of curvature R and the contact pressure P may be set to the above formulas and other sizes that satisfy the formulas.

In the above structure, the applied voltage Vp to each control electrode 10 during the image forming operation is, for example, -50.
Deflection electrodes 11a, 11 between V, 200V and 250V
The applied voltages VDD-L and VDD-R to b are, for example, 150
The voltage is switched among V, 0V, and -150V at the timings shown in FIG. 5, and the voltage applied to the back electrode 6 is set to 1000V, for example.

In FIG. 5, deflection electrodes 11a and 11b are provided.
Is 0V, the control electrode 10 is -50V, and the electric field generated by the back electrode 6 is attracted to the toner carrier 1 by the toner 2
From the state in which it is not affected, first, + 150V is applied to the left deflection electrode 11a and -150 is applied to the right deflection electrode 11b.
In the state in which V is applied and the negatively charged toner 2 is deflected to the left, a voltage of 250 V is first applied to the control electrode 10 to peel off the toner 2 adsorbed on the toner carrier 1, and then 200 V is applied. By applying the voltage of
As shown in FIG. 4A, the toner 2 passes through the toner passage hole 4 and is deflected to the left to fly, and is, for example, about 40 μm on the left side of the position facing the toner passage hole 4 on the facing member 7. Toner is applied to the displaced position. Next, with the left and right deflection electrodes 11a and 11b both set to 0 V, a voltage is applied to the control electrode 10 in the same manner as described above, and as shown in FIG. The toner 2 is applied to the position facing the hole 4.
Next, in the state where −150V is applied to the left deflection electrode 11a and + 150V is applied to the right deflection electrode 11b so that the −charged toner 2 is deflected to the right, a voltage is applied to the control electrode 10 in the same manner as above. By doing so, as shown in FIG. 4C, the toner is applied to the position on the facing member 7 which is also displaced by about 40 μm to the right of the position facing the toner passage hole 4. Thus, the control electrode 10 and the deflection electrode 11
By sequentially switching the applied voltage to a and 11b, the toner is applied to the left, right, and center three points by one toner passage hole 4.

Even when the toner 2 is prevented from passing through the toner passage hole 4, the voltage applied to the control electrode 10 is temporarily changed from -50V to 0V as shown by the phantom line, so that The toner 2 that is charged to the opposite polarity (+ polarity) and is deposited on the surface of the toner passage control unit 3 is adsorbed by the toner carrier 1 and returns to the negatively charged toner 2 side. The oppositely-polarized toner 2 deposited above 10 is used as a core to prevent negatively charged toner 2 from depositing around the toner passage hole 4 and causing clogging of the toner passage hole 4.

At that time, since the radius of curvature R in the vicinity of the contact position Cp of the toner passage control means 3 satisfies the above expression, the radius of curvature R is larger than the radius r of the toner carrier 1. (R <R), since the toner carrier 1 contacts the spacer 12 only at the contact position Cp, the distance ΔLk between the toner carrier 1 and the toner passage control means 3 at the position where the toner passage holes 4 and 4 are arranged is set. By ensuring an appropriate size, it is possible to prevent contamination of the facing member 7 due to fogging.

On the other hand, since the radius of curvature R is smaller than 4r (R <4r), the interval ΔLk does not exceed the appropriate range, so that it is possible to prevent the density of the formed image from being diluted. . Further, since the difference in the distance between the toner passage control means 3 and the toner carrier 1 in each of the two rows of toner passage holes 5 and 5 is suppressed, it is formed by each of the toner passage holes 5 and 5. It is possible to prevent the occurrence of density unevenness by making the density difference between the formed images as small as possible.

That is, since the interval ΔLk can be set to an appropriate size, fogging is caused by preventing the toner carrier 1 and the toner passage control means 3 from coming into contact with each other at a position other than the contact position Cp. It is possible to prevent the occurrence of the above-mentioned problem and to improve the image quality by appropriately adjusting the density of the formed image.

By setting the contact pressure P between the spacer 12 and the toner carrier 1 so as to satisfy the above formula, the contact pressure P is larger than 0.005 N / mm ² (0.005 N / mm ^2). mm ² <P), toner carrier 1
Since the toner passage control means 3 follows the eccentricity of the rotation axis of the toner carrier 1 and always contacts in the same state, the interval ΔLk can be stabilized. Therefore, the density of the formed image can be stabilized.

On the other hand, since the contact pressure P is smaller than 0.2 N / mm ² (P <0.2 N / mm ² ), the contact position Cp
Since the toner 2 on the toner carrier 1 is not scraped off by the spacer 12, it is possible to prevent a decrease in the density of the formed image due to a thin toner layer on the toner carrier 1.

Therefore, the toner carrier 1 is brought into uniform contact with the spacer 12 on the toner passage control means 3 so that the distance ΔLk.
Can be stably ensured, and the density of the formed image can be made appropriate.

In this embodiment, the image forming apparatus which satisfies both the formula and the formula at the same time is shown. However, the present invention is not limited to this, and the constitution is made so as to satisfy the formula or one of the formulas. Good.

The spacer 12 is not limited to this embodiment and may not be electrically grounded.
Alternatively, an insulating material such as resin may be used as the material. Also,
The spacer 12 may have a thickness of 0, that is, the toner passage control means 3 itself may be used as the spacer.
It does not impair the gist of the present invention.

[0056]

EXAMPLES Next, concretely implemented examples will be described.

(A) Relation between radius of curvature R and image quality In the image forming apparatus described in the above embodiment also shown in FIGS. 1 and 2, the radius of curvature R of the toner passage control means 3 near the contact position Cp. And the relationship between the quality of the formed image and the quality of the formed image were examined. Various parameters forming the image forming apparatus are as follows.

That is, the radius r of the toner carrier 1 is set to 9 m.
m, the thickness of the toner passage control means 3 is 0.1 mm, and the rigidity of the toner passage control means 3 is 150 Nmm ² . Then, one end portion of the toner passage control means 3 is fixed to the holding means 14
While the other side is fixedly supported by the elastic holding means 24, the roller side surface of the toner carrier 1 is set to a constant value of 0.1 N / at the center between the one end and the other end. The contact pressure was set to mm ² .

Then, the holding position of the toner passage control means 3 by the holding means is adjusted so that the radius of curvature R is about 1.5 times the radius r of the toner carrier 1 (R = 1.5r). The one having a certain thickness of 14 mm is the first embodiment. Similarly, the radius of curvature R is 7.2 mm (R = 0.8r), 45 m
Those having m (R = 5r) are referred to as a first comparative example and a second comparative example, respectively.

The radius of curvature R was measured by the measuring system shown in FIG. In the figure, the passing direction of the toner 2 (horizontal direction in the figure) is taken as the Y axis, and the direction orthogonal to the Y axis and the axis center of the toner carrier 1 (the vertical direction in the figure) is taken as X.
The axis. Further, the intersection point of the X and Y axes is the origin O. Then, a CCD laser displacement sensor (LK-030, manufactured by Keyence Corporation) 53 is arranged at a predetermined interval from the toner passage control means 3. By measuring the distance to the toner passage control means 3 while moving the CCD laser displacement sensor 53 in the X-axis direction, a graph showing the shape of the toner passage control means 3 as shown in FIG. 8 can be obtained. still,
The downward direction in FIG. 7 and the rightward direction in FIG. 8 are the positive direction of the X axis, and the rightward direction in FIG. 7 and the upward direction in FIG. 8 are the positive direction of the Y axis.

The distance between the displacement sensor 53 and the toner passage control means 3 at the position where the toner passage hole array on the toner passage control means 3 is arranged and the position moved ± 1 mm from this position in the X-axis direction. Was measured respectively. Specifically, the graph shown in FIG. 8 is regarded as a function Y = S (X), and the magnitude of Y when X = -1, 0, 1 is calculated.
That is, three points Y = S (−1), S (0), and S (1) are measured, and the radius of curvature R is calculated as the radius of the circle passing through these three points.

These first embodiment, first comparative example, and second
For each of the comparative examples, the image forming apparatus was operated to form an image, and the density of the formed image was measured. As shown in FIG. 12, regarding the density of the formed image, the density of the printed portion was measured with a Macbeth densitometer. In particular,
The so-called solid tone formed image 55a having the highest density has a Macbeth density of 1.4 or more, and the intermediate tone formed image 55b has a Macbeth density of 0.5 to 0.7. That is, the high image quality is set. In addition, the fog (that is, the stain on the non-printed portion 56 on the recording paper) was measured by the Macbeth densitometer for the density of the non-printed portion 56 on the recording paper.

As a result, in the case of the first comparative example in which the radius of curvature R is equal to or smaller than the radius r of the toner carrier 1 (R = 0.8r), as shown in FIG. Will contact the toner passage control means 3 at a position other than the contact position Cp. Therefore, it was confirmed that fogging occurred and the non-printed area of the recording paper as the facing member was contaminated.

On the other hand, the radius of curvature R is 4r or more (R = 5r).
In the second comparative example, as shown in FIG. 11B, the interval ΔLk becomes large and the solid image 55 is formed.
The average Macbeth densities of the a and half-tone formed images 55b were 1.1 and 0.2, respectively, which were smaller than the above high image quality conditions, and the image quality of both images 55a and 55b deteriorated. In the second comparative example, the image density was not uniform, and uneven density was observed.

On the other hand, in the first embodiment in which the radius of curvature R satisfies the above expression (R = 3r), the Macbeth densities of the solid image 55a and the halftone image 55b are 1.4. , 0.6, and a high-quality formed image was obtained.

(B) Relationship between Contact Pressure P and Image Next, the relationship between the contact pressure P of the toner passage control means 3 and the toner carrier 1 and the image quality of the formed image was examined. Various parameters constituting the image forming apparatus are the same as those shown in (a) above. The toner passage control means 3 is also held in the same manner. Then, the curvature radius R of the toner passage control means 3 near the contact position Cp is set to a constant value of R = 14 mm.

Then, the roller side surface of the toner carrier 1 is pressed against the central portion of the toner passage control means 3,
By changing the pressing force, the contact pressure P between the toner passage control means 3 and the toner carrier 1 is changed.

The contact pressure P was measured by a spring weigher 54 as shown in FIGS. That is, as shown in the figure, the cylindrical protrusions 1a, 1a having ring-shaped tips integrally formed with the springs of the springs 54, 54 are formed at both axial ends of the toner carrier 1. The toner carrier 1 was pressed against the toner passage control means 3 in a state where the toner carrier 1 was inserted, and the pressing force was measured. Then, the contact pressure P is changed to 0.1 N / mm ² , 0.
Those having 002 N / mm ² and 0.24 N / mm ² are referred to as a second example, a third comparative example and a fourth comparative example, respectively.

The second example, the third comparative example, and the fourth example
For each of the comparative examples, the image forming apparatus was operated to form an image, and as in the case of (a) above,
The density of the formed image was measured with a Macbeth densitometer. The same applies to high-quality conditions.

As a result, the contact pressure P was 0.005 N / m.
In the case of the third comparative example of m ² or less (P = 0.002 N / mm ² ), the interval ΔLk became unstable and the density of the formed image became unstable.

On the other hand, in the case of the fourth comparative example in which the contact pressure P is 0.2 N / mm ² or more (P = 0.24 N / mm ² ), the toner 2 on the toner carrier 1 at the contact position Cp A scraped state was observed. The Macbeth densities of the solid-tone formed image 55a and the half-tone formed image 55b are 1.2 and 0.3, respectively, which are smaller than the above high-quality conditions, and the image quality of both images 55a and 55b deteriorates.

On the other hand, in the second embodiment in which the contact pressure P satisfies the above formula (P = 0.1 N / mm ² ), the solid image 55a and the halftone image 5 are formed.
The Macbeth concentrations of 5b are 1.4 and 0.6, respectively,
A high quality formed image was obtained.

[0073]

As described above, according to the first aspect of the present invention, the toner carrying member composed of the roller carrying and carrying the toner, the facing member arranged to face the toner carrying member, and the toner carrying member. A toner passage hole arranged between the bodies, for passing the toner toward the facing member side, has a toner passage hole array arranged parallel to the axis of the toner carrier,
An image forming apparatus including a toner passage control unit that controls passage of toner through a toner passage hole based on an image signal from the outside, and a spacer that is provided on the toner passage control unit and abuts on a toner carrier. When the radius of the carrier is r and the radius of curvature of the toner passage control means at the contact position of the spacer and the toner carrier is R, r <R <
By satisfying 4r, the occurrence of fogging can be prevented, and the interval ΔLk between the toner carrier and the toner passage control means can be set to an appropriate size, and the density of the formed image can be made appropriate to improve the image quality. Can be achieved.

According to the second aspect of the invention, the toner is carried while being carried.
Toner carrier consisting of a sending roller and toner carrier
It is arranged between the facing member and the toner carrier which are arranged facing each other.
Toner that is installed to pass the toner toward the facing member.
-Toner whose through holes are arranged parallel to the axis of the toner carrier
-There is a through hole array that allows toner to pass through the toner passage hole.
Toner passage that controls excess based on image signals from the outside
The toner is provided on the control means and the toner passage control means.
An image forming apparatus provided with a spacer that abuts the carrier.
And the contact pressure P between the spacer and the toner carrier is 0.
005 N / mm ²<P <0.2 N / mm²To be satisfied
The toner carrier to the space on the toner passage control means.
To evenly contact the blade to secure the above-mentioned interval ΔLk stably.
And the density of the formed image is appropriate.
be able to.

[Brief description of drawings]

FIG. 1 is a front view showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is an enlarged vertical sectional front view of the vicinity of a toner passage hole of the image forming apparatus.

FIG. 4 is a vertical cross-sectional side view showing three operating states of an arbitrary toner passage hole.

FIG. 5 is a timing diagram of applied voltages to a control electrode and a deflection electrode.

FIG. 6 is a plan view showing an arrangement state of each electrode.

FIG. 7 is an explanatory diagram showing a measuring system of a radius of curvature R.

FIG. 8 is an explanatory view schematically showing the shape of the measured toner passage control means.

FIG. 9 is a perspective view schematically showing a toner carrier and springs.

FIG. 10 is an explanatory diagram showing a method for measuring the contact pressure between the toner carrier and the toner passage control means.

FIG. 11 is a front view showing a contact state between a toner carrier and a toner passage control unit.

FIG. 12 is an explanatory diagram showing an image formed on a recording sheet.

FIG. 13 is a main part configuration diagram of a conventional image forming apparatus.

FIG. 14 is a configuration diagram showing an overall configuration of a conventional image forming apparatus.

FIG. 15 is a plan view showing an arrangement state of electrodes in the conventional example.

[Explanation of symbols]

Cp contact position P contact pressure R radius of curvature r Toner carrier radius 1 Toner carrier 2 toner 3 Toner passage control means 4 Toner passage hole 5 Toner passage hole row 7 Opposing member 12 spacers

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasutaka Tamai             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Akira Fukano             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Taichi Ito             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 2C162 AE08 AE25 AE31 AE47 AE56                       AE69 AE74 AF13 AF51 CA03                       CA12 CA24                 2H029 DB00

Claims (3)

[Claims] 1. A toner carrier comprising a roller carrying and carrying toner, a facing member arranged facing the toner carrier, and a member arranged between the toner carrier and the facing member. The toner passing holes for passing the toner of the toner carrying member toward the facing member have a toner passing hole array arranged in parallel with the axis of the toner carrying member, and the toner passes through the toner passing hole. An image forming apparatus comprising: a toner passage control unit that controls the toner passage unit based on an image signal from the outside; and a spacer that is provided on the toner passage control unit and is in contact with the toner carrier. When the radius is r, and the radius of curvature of the toner passage control means at the contact position of the spacer and the toner carrier is R, r <R <4r is satisfied. . 2. A toner carrier comprising a roller carrying and carrying toner, a facing member arranged facing the toner carrier, and a member arranged between the toner carrier and the facing member. The toner passing holes for passing the toner of the toner carrying member toward the facing member have a toner passing hole array arranged in parallel with the axis of the toner carrying member, and the toner passes through the toner passing hole. An image forming apparatus comprising: a toner passage control unit that controls the toner passage based on an image signal from the outside; and a spacer that is provided on the toner passage control unit and abuts on the toner carrier. contact pressure P of the body, the image forming apparatus characterized in that it satisfies the ^{0.005N / mm 2 <P <0.2N} / mm 2. 3. A toner carrier comprising a roller for carrying and carrying toner, a facing member arranged facing the toner carrier, and a member arranged between the toner carrier and the facing member, The toner passing holes for passing the toner of the toner carrying member toward the facing member have a toner passing hole array arranged in parallel with the axis of the toner carrying member, and the toner passes through the toner passing hole. An image forming apparatus comprising: a toner passage control unit that controls the toner passage unit based on an image signal from the outside; and a spacer that is provided on the toner passage control unit and is in contact with the toner carrier. The radius is r, the radius of curvature of the toner passage control means at the contact position between the spacer and the toner carrier is R, and the contact pressure between the spacer and the toner carrier is P.
When a, r <image forming apparatus characterized in that it satisfies ^{R <4r 0.005N / mm 2 <} P <0.2N / mm 2 at the same time.