JP2002273928A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate appropriate setting of an interval ΔLk between a toner carrier 1 and a toner passing controlling means 3 and to improve quality of a formed image by indirectly providing a contact distance ΔCp from a standard face passing through a straight line dividing a region S of passing hole rows where toner passing hole rows 5 and 5 in the toner passing controlling means are arranged into two equal parts in the width direction and a straight line passing through a center O of a curvature radius R in the neighborhood of the toner passing hole rows 5 and 5 and extending in the direction of the toner passing hole rows 5 and 5 to a contact position Cp of a spacer 12 and the toner carrier 1 in an image forming apparatus. SOLUTION: A constitution is provided in such a way that the contact distance ΔCp is exclusively determined only in accordance with the axial center distance Δe from the standard face L to the axial center of the toner carrier 1. Namely, it is constituted in such a way that when k is a constant, ΔCp=kΔe and 1.1<=k<=1.7 are satisfied.

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, a printer, and the like. More particularly, the present invention controls the flying of toner from a toner carrier to an opposing member, and applies toner to the opposing member. The present invention belongs to a technical field related to an image forming apparatus that forms an image by being attached thereto.

[0002]

2. Description of the Related Art In recent years, with the improvement of personal computer capabilities and the advancement of network technology, there has been an increasing demand for printers and copiers capable of handling a large amount of documents and capable of handling color documents. ing. However, an image forming apparatus capable of outputting satisfactory high-quality black and white or color documents and having a high processing speed is under development and is expected to appear.

As one of them, a so-called "toner jet (registered trademark)" type image forming technique for forming an image by causing toner to fly on an image receiving means such as a recording paper or an intermediate image carrying belt by the action of an electric field is known. Have been.

An image forming apparatus of this kind is disclosed in
No. 4-26333 and U.S. Pat. No. 3,689,935.
Japanese Unexamined Patent Application Publication No. 60-20747 and Japanese Patent Publication No. 9-500842 are known. One example is Japanese Patent Application No. 10-100780.
What is disclosed in the above item will be described with reference to FIG.

In FIG. 12, reference numeral 31 denotes a grounded toner carrier for carrying and transporting the charged toner, and reference numeral 32 denotes a regulating blade which controls the toner on the toner carrier 31 in one to three layers and further charges the toner. . A supply roller 33 supplies the toner to the toner carrier 31 and charges the toner. Numeral 34 denotes a toner passage control means.
5 are formed, and a control electrode 36 is provided therearound. A voltage corresponding to an image signal is applied to the control electrode 36 from a control power supply 37. 38 is a back electrode, 39
Is a back electrode power supply. Reference numeral 40 denotes an image receiving unit such as a recording paper conveyed on the back electrode 38.

In the above-described configuration, the supply roller 33 and the toner carrier 31 are operated to form a uniform toner layer on the toner carrier 31 by the regulating blade 32 and to convey the toner. Apply voltage to 38,
When a voltage corresponding to an image signal is applied to the control electrode 36 by a control power supply 37 such as a drive IC while moving the image receiving means 40 in synchronization with the movement, the toner on the toner carrier 31 responds to the image signal. Then, the toner flies and adheres to the image receiving means 40 through the toner passage hole 35, and a required image is formed on the image receiving means 40.

By the way, for example, 6
In order to form a fine image of 00 dpi (a density of 600 dots per inch), it is necessary to arrange the toner passage holes 35 at such a pitch in the toner passage control means 34. As shown in FIG. 14, a large number of rows (eight rows in the illustrated example) of toner passage holes 35 and control electrodes 36 are arranged. The toner passage hole 35 and the control electrode 36 are circular, and connection electrodes that are electrically connected to the control electrodes 36 extend on both sides in the moving direction of the toner carrier 31 to avoid mutual interference, and drive ICs that output control voltages respectively. Connected to the lead.

FIG. 12 shows an example in which the image receiving means 40 is made of recording paper or the like and an image is formed directly on the recording paper or the like. In the case of a color printer, there are problems such as difficulty in synchronizing the image forming timing of each color due to variations in the conveyance of recording paper and deterioration of image quality. As disclosed in JP-A-100780, it may be preferable to use an intermediate image carrying belt as the image receiving means 40 and to transfer the images formed on the image carrying belt to recording paper or the like at once. .

This will be described with reference to FIG.
Reference numeral denotes an endless image carrying belt as the image receiving means 40, which is formed 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 44a and 44b. A pickup roller 45 feeds the recording paper 46 one by one from a paper feed tray, a timing roller 47 synchronizes the image position with the fed recording paper 46, and a toner image 48 formed on the image carrying belt 42. The transfer roller is a transfer roller that transfers the image to the recording paper 46. The transfer roller is pressed toward the roller 44 a 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 onto which the toner image has been transferred.

[0010]

In the above-described image forming apparatus, the amount of toner passing through the toner passage hole is determined by the distance between the toner carrier and the toner passage control means provided with the control electrode. It is greatly affected by ΔLk. That is, when the interval ΔLk is too small,
While the amount of toner passing through the toner passage hole increases, causing a problem of so-called fogging in which the opposing means such as recording paper becomes dirty, while the interval ΔLk becomes too large, the amount of toner passing through the toner passage hole decreases. As a result, there arises a problem that the formed image becomes thin. Therefore, in order to improve the quality of the formed image, it is necessary to appropriately secure the interval ΔLk between the toner carrier and the toner passage control unit.

The toner passage hole passing through the center of the radius of curvature near the toner passage hole array and a straight line bisecting the passage hole array region where the toner passage hole array is disposed in the toner passage control means in the width direction. A plane passing through a straight line extending in the column direction is defined as a reference plane, and a contact distance ΔCp from this reference plane to a contact position Cp of a spacer provided on the toner passage control means so as to contact the toner carrier with the toner carrier. Is set to a target value within a predetermined range, the distance Δ
It is conceivable to secure Lk.

However, in practice, when the contact distance ΔCp is changed, parameters such as the contact pressure between the spacer and the toner carrier and the curvature of the toner passage control means are also changed. I will. In other words, there is a problem that it is extremely difficult to properly secure the interval ΔLk by setting the contact distance ΔCp to the magnitude of the target value.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to control parameters such as a contact pressure between a spacer and a toner carrier and a curvature of a toner passage control means in an image forming apparatus. Without changing, the contact distance ΔC
An object of the present invention is to make it possible to indirectly define p so that it is easy to appropriately secure the interval ΔLk between the toner carrier and the toner passage control unit, and to improve the quality of a formed image.

[0014]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a toner carrier comprising a roller for carrying and transporting toner, and a toner carrier disposed opposite to the toner carrier. And a toner passage hole, which is provided between the opposed member and the toner carrier and the opposed member and passes the toner of the toner carrier toward the opposed member, is arranged in parallel with the axis of the toner carrier. A toner passage control means for controlling the passage of toner through the toner passage holes based on an external image signal; and a toner carrier on the toner passage control means. It is assumed that the image forming apparatus includes a spacer provided to be in contact with the image forming apparatus. A straight line bisecting the passage hole array region where the toner passage hole array is disposed in the toner passage control means in the width direction and a center of the radius of curvature near the toner passage hole array and passing through the toner passage hole array direction. The contact distance ΔCp from the reference plane passing through the straight line extending to the contact position between the spacer and the toner carrier is uniquely determined only according to the axial distance Δe from the reference plane to the axis of the toner carrier. It is characterized by being done.

Further, according to the second aspect of the present invention, a toner carrier comprising a roller for carrying and transporting the toner, an opposing member disposed opposite to the toner carrier, the toner carrier and the opposing member And a toner passage hole array in which toner passage holes for passing the toner of the toner carrier toward the opposing member are arranged in parallel with the axis of the toner carrier. Image formation comprising: toner passage control means for controlling the passage of toner through a toner passage hole based on an external image signal; and a spacer provided on the toner passage control means so as to contact the toner carrier. The device is assumed. Then, a reference plane extending in a direction in which the toner passes from the toner carrier to the opposing member passes through a straight line bisecting the width direction of the passage hole array region in which the toner passage hole array is provided in the toner passage control means. ,
The contact distance ΔCp from the contact position between the spacer and the toner carrier is uniquely determined according to only the axis distance Δe from the reference plane to the axis of the toner carrier.

According to these inventions, the contact distance ΔCp
Is uniquely determined only according to the axial distance Δe,
A parameter that is a precondition for the target value of the contact distance ΔCp described above, that is, a contact pressure between the spacer and the toner carrier,
The contact distance ΔCp can be indirectly defined by the axial center distance Δe without changing other parameters such as the curvature of the toner passage control means at the contact position. That is, the setting of the axial center distance Δe is not direct,
Indirectly defining the contact distance ΔCp, the distance ΔLk between the toner carrier and the toner passage control means can be easily and appropriately set, and the amount of toner passing through the toner passage hole is adjusted appropriately. Image quality can be improved.

According to the third aspect of the present invention, when a constant is k, ΔCp = kΔe ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 1.1 ≦ k ≦ 1.7 ‥‥‥‥ ‥‥‥‥‥‥‥‥‥‥‥‥‥ is satisfied.

When the constant k is smaller than 1.1, the values of the contact distance ΔCp and the axial center distance Δe become smaller, and the radius of curvature near the toner passage hole array becomes larger. At this time, when the axial distance Δe increases, the interval ΔLk rapidly increases, and the density of the formed image decreases.
Lk cannot be set to an appropriate size. That is, an appropriate value of the axial center distance Δe cannot be obtained.

On the other hand, when the constant k is larger than 1.7, the radius of curvature in the vicinity of the row of toner passage holes becomes small and becomes very close to the radius of the toner carrier, so that the contact position becomes unstable. Further, since the interval ΔLk becomes small, so-called fogging occurs. At this time, the axial center distance Δe
However, since the rate of increase of the interval ΔLk with respect to the increase of the axial center distance Δe is small, this fogging cannot be eliminated.

Therefore, according to the configuration of the present invention, it is possible to obtain an appropriate value of the axial center distance Δe for setting the interval ΔLk at which the amount of toner passing through the toner passage hole becomes appropriate. Then, by setting the axial center distance Δe, the contact distance ΔCp is indirectly defined, and the desired distance Δ
Lk can be easily set, and the quality of the formed image can be improved.

According to the fourth aspect of the present invention, when the constant is k, ΔCp = kΔe ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 1.2 ≦ k ≦ 1.6 ‥‥ ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ is preferably satisfied.

According to the fifth aspect of the present invention, when the constant is k, ΔCp = kΔe ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ k = 1.4 ‥‥‥‥‥‥‥‥ ‥‥‥‥‥‥‥‥‥ is satisfied. As a result, a desirable value of the constant k can be obtained.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1 showing a schematic configuration of the image forming apparatus of the present embodiment, reference numeral 1 denotes a toner carrier which carries and conveys charged toner 2, which is formed of a grounded rotatable roller, and which is charged with toner 1. It is adsorbed in a thin state of up to three layers.

Reference numeral 3 denotes a toner passage control unit, the structure of which will be described in detail later. Usually, the toner passage control unit 3 is made of a flexible resin film such as polyimide containing control electrodes. The toner passage control means 3 is supported by a fixed body such as a casing at both ends in a direction perpendicular to the axial direction of the toner carrier 1, and at least one of the both ends is elastically supported. In the present embodiment, the toner passage control means 3 is elastically supported by a fixed body via a spring 13 on the upper side (upper side in the drawing) of the toner 2 in the conveying direction near the toner passage hole array 4 described later, On the side (lower side in the figure), it is fixedly supported by the fixed body. Incidentally, the toner passage control means 3 may be fixedly supported by the fixed body on the upper side, and may be elastically supported by the fixed body on the lower side.

At this time, the contact pressure between the toner carrier 1 and the toner passage control means 3 generated by the spring 13 is set to 0.1.
002 to 0.2 N / mm ² is appropriate (for example, when the contact length is 200 mm, the contact width is 0.5 mm, and the contact force is 2 N, the contact pressure is 0.02 N / mm ² ). This is because the toner carrier 1 and the toner carrier 1 always follow the eccentricity of the rotation axis of the toner carrier 1 in order to always maintain the interval between the toner carrier 1 and the toner passage control means 3 at the toner passage hole. This is because the passage control means 3 must be in contact in the same state, and the toner layer on the toner carrier 1 must not be deformed by too strong contact pressure. This contact pressure slightly fluctuates depending on the material of the toner carrier 1 and the toner passage control means 3 and the like.

Reference numeral 6 denotes a back electrode which is composed of a rotatable roller and is disposed 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 carrying belt which is disposed 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.

As shown in FIGS. 1 and 2, the toner passage control means 3 is disposed between the toner carrier 1 and the opposing member 7, and passes the toner 2 of the toner carrier 1 toward the opposing member 7. A toner passage hole array 5 in which toner passage holes 4 to be formed are arranged in parallel with the axis of the toner carrier 1 is provided. More specifically, in the toner passage hole array 5, the toner passage holes 4 are arranged along the axial direction of the toner carrier 1, and in this embodiment, the two toner passage hole arrays 5 and 5 are close to each other. It is provided so that

The toner passage control means 3 controls the passage of the toner 2 through the toner passage hole array 5 based on an external image signal. That is, as shown in FIG.
Main film 8 of about 50 μm thickness and 10 to 10
10-3 pasted with an adhesive layer of about 15 μm thickness
It is composed of a three-layer polyimide resin film composed of upper and lower cover films 9a and 9b having a thickness of about 0 μm.
In addition, the material and dimensions of each film, the number of constituent layers, and the like are not limited thereto, and may be arbitrarily designed. In FIG. 2, the control electrode 1 is provided on the upper surface of the main film 8 so as to surround the periphery of each toner passage hole 4.
A pair of deflecting electrodes 11a, 11b are provided 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 by 8 to 2
It is composed of a Cu film having a thickness of about 0 μm.

The opening shape of the toner passage hole 4 is circular as shown in FIG. 5A, but may be oval or elliptical. Dimensionally, the diameter is set to about 70 to 120 μm. The surface roughness R of the inner peripheral wall surface of the toner passage hole 4 is equal to or less than the average particle diameter of the external additive of the toner 2.
The thickness is 1 to 0.5 μm or less. Such a surface roughness R
Can be formed by forming a hole with an excimer laser or a press, or may be formed by forming a hole with a YAG laser, a CO ₂ laser, or the like, and then performing post-processing such as etching.

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. Further, as shown in FIG. 5B, the deflecting electrodes 11a and 11b are shared by the adjacent toner passage holes 4.

Further, a spacer 12 having a predetermined thickness is provided on the toner passage control means 3 so as to be in contact with the toner carrier 1. That is, the spacer 12 is provided on the surface of the toner passage control unit 3 facing the toner carrier 1 and is fixed to the vicinity of the toner passage hole arrays 5 and 5. Spacer 1
2 is electrically grounded and has a thickness of 5 to 20 μm
It is preferably 10 μm in the present embodiment.

As a characteristic of the present invention, as shown in FIGS.
Is a region where the toner passage hole arrays 5 and 5 are disposed, and the passage hole array region S extending in a belt shape along the toner passage hole array is arranged in the width direction (that is, the toner conveyance in the vicinity of the toner passage hole array). Direction) and a plane passing through a reference straight line extending in the direction of the row of toner passing holes and a straight line passing through the center O of the radius of curvature R near the row of toner passing holes 5 and 5 and extending in the direction of the row of toner passing holes. is there. The image forming apparatus according to the present embodiment has a contact distance ΔCp from the reference plane L to the contact position Cp between the spacer 12 and the toner carrier 1.
Is uniquely determined in accordance with only the axis distance Δe from the reference plane L to the axis of the toner carrier 1.

That is, the image forming apparatus according to the present embodiment satisfies the relational expression of ΔCp = kΔe ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥, where k is a constant. It is configured. Further, the constant k is set so as to satisfy 1.1 ≦ k ≦ 1.7 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥.

In the above configuration, the voltage Vp applied to each control electrode 10 during the image forming operation is, for example, −50.
V, 200 V and 250 V, the deflection electrodes 11 a and 11
The applied voltages VDD-L and VDD-R with respect to b are, for example, 150
The voltage is switched between V, 0 V, and -150 V at the timing shown in FIG. 4, and the voltage applied to the back electrode 6 is, for example, 1000 V.

In FIG. 4, the deflection electrodes 11a and 11b
Are 0V, the control electrode 10 is set to -50V, and the electric field generated by the back electrode 6 is applied to the toner 2 adsorbed on the toner carrier 1.
First, +150 V is applied to the left deflection electrode 11a, and -150 V is applied to the right deflection electrode 11b.
In a state in which the charged toner 2 is deflected to the left by applying V, 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 the 200 V By applying the voltage of
As shown in FIG. 3A, the toner 2 passes through the toner passage hole 4 and deflects to the left and flies, and is, for example, about 40 μm to the left of the position facing the toner passage hole 4 on the opposing member 7. The toner is applied to the displaced position. Next, in a state where both the left and right deflection electrodes 11a and 11b are set to 0V, a voltage is applied to the control electrode 10 in the same manner as described above, so that the toner passing through the opposing member 7 as shown in FIG. The toner 2 is applied to a position facing the hole 4.
Next, while applying -150 V to the left deflection electrode 11a and +150 V to the right deflection electrode 11b to deflect the negatively charged toner 2 to the right, a voltage is applied to the control electrode 10 in the same manner as described above. As a result, as shown in FIG. 3C, the toner is applied to a position on the opposing member 7 which is displaced by about 40 μm to the right from the position opposing the toner passage hole 4. Thus, the control electrode 10 and the deflection electrode 11
The toner is applied to the left, right, and center three points by one toner passage hole 4 by sequentially switching the applied voltages to a and 11b.

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 a virtual line, so that the The control electrode moves in such a manner that the toner 2 charged to the opposite polarity (+ polarity) and deposited on the surface of the toner passage control means 3 is attracted to the toner carrier 1 and returns to the negatively charged toner 2 side. The negatively charged toner 2 accumulated above the core 10 prevents the charged toner 2 from accumulating around the toner passage hole 4 and causing clogging of the toner passage hole 4.

At this time, in order to improve the formed image, the distance ΔLk between the toner carrier 1 and the toner passage control means 3 is set by setting the magnitude of the contact distance ΔCp to a target value within a predetermined range. It is conceivable to secure it appropriately. However, actually, when the contact distance ΔCp is changed, parameters such as the contact pressure between the spacer 12 and the toner carrier 1 and the radius of curvature R of the toner passage control means 3 also change. Will change. That is,
It is difficult to properly secure the interval ΔLk by setting the contact distance ΔCp to the magnitude of the target value.

On the other hand, according to the configuration of the present invention, the contact distance ΔCp is uniquely determined only in accordance with the axial center distance Δe. The contact distance ΔCp can be indirectly defined by the axial center distance Δe without changing various parameters. That is, the distance ΔLk between the toner carrier 1 and the toner passage control means 3 is easily and appropriately set by setting the contact distance ΔCp indirectly, not directly, by setting the axial center distance Δe. be able to. Therefore, the quality of the formed image can be improved by appropriately setting the amount of toner passing through the toner passage hole 4.

Further, since the image forming apparatus according to the present embodiment is configured to satisfy the above formulas and the formulas, it is necessary to set the interval ΔLk at which the amount of toner passing through the toner passage hole 4 becomes appropriate. Can be obtained.

That is, when the constant k is smaller than 1.1, the values of the contact distance ΔCp and the axial center distance Δe are close, and the radius of curvature R near the toner passage hole arrays 5 and 5 is large. At this time, if the axial distance Δe increases, the interval ΔLk increases rapidly, and the density of the formed image decreases, so that the interval ΔLk cannot be set to an appropriate size. That is, an appropriate value of the axial center distance Δe cannot be obtained.

On the other hand, when the constant k is larger than 1.7, the radius of curvature R near the toner passage hole arrays 5 and 5 becomes small and becomes very close to the radius of the toner carrier 1, so that the contact position is unstable. Will be. In addition, the interval ΔLk
Is reduced, so-called fogging occurs. At this time, even if the axial distance Δe is increased, the rate of increase of the interval ΔLk with respect to the increase of the axial distance Δe is small.
This fog cannot be eliminated.

Therefore, an appropriate value of the axial distance Δe can be obtained, and by setting the axial distance Δe, the contact distance ΔCp is indirectly defined, and the desired distance ΔLk
Can be easily set, and the quality of the formed image can be improved.

In the above-described embodiment, the reference plane L is defined as a reference straight line that divides the passage hole array area S where the toner passage hole arrays 5 and 5 are arranged in the toner passage control means 3 into two in the width direction. , The center O of the radius of curvature R near the toner passage hole arrays 5 and 5
And a plane passing through the straight line extending in the direction of the row of toner passing holes. However, instead of this, it is an area where the rows of toner passing holes 5 and 5 in the toner passing control means 3 are arranged,
The passage hole array region S extending in a band along the toner passage hole arrays 5 and 5 extends in the width direction (that is, the toner passage hole arrays 5 and 5).
(The conveying direction of the toner 2 in the vicinity), and passes through a reference straight line extending in the direction of the toner passage hole rows 5 and 5 and extends in the direction of passage of the toner 2 from the toner carrier 1 to the facing member 7 such as recording paper. It may be a plane. Even when the reference plane is defined in this manner, the same operation and effect as the above embodiment can be obtained.

Further, the image forming apparatus is configured so that the constant k satisfies 1.2 ≦ k ≦ 1.6 ≦ together with the above formula. Even when the range of the constant k is defined in this manner, the toner carrier 1
It is preferable to appropriately secure an interval ΔLk between the image forming apparatus and the toner passage control unit 3 to improve the quality of a formed image.

Further, the above constant k
May be configured such that satisfies k = 1.4 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥. As a result, a desirable value of the constant k can be obtained.

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

[0047]

FIG. 6 schematically shows the image forming apparatus shown in the above embodiment in which the toner carrier 1 is held, the radius of curvature R of the toner passage control means 3 near the toner passage hole 4, and the like. The relationship between the magnitude of the contact distance ΔCp and the axial center distance Δe and the image quality of the formed image when is set to a predetermined value was examined.

Various specification parameters in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in the upper part of Table 1.

[0049]

[Table 1]

Specifically, the radius of the toner carrier 1 is 9 m
m, the thickness of the toner passage control unit 3 is 0.1 mm, the rigidity of the toner passage control unit 3 is 150 Nmm ^2, and one end of the toner passage control unit 3 is fixedly supported, while the other end (upper side in FIG. 6) As indicated by the arrow inside, the contact position C
A tension of 5N was applied in a direction away from p to support.

As shown in FIG. 6, a contact position C between the toner carrier 1 and the spacer on the toner passage control means 3 is also set.
p is the origin O, the tangential direction at the origin O contacting the toner carrier 1 is the X direction (the upward direction in the figure is the positive direction), and the direction orthogonal to the X direction is the Y direction (the right direction in the figure is the right direction). Set the coordinate system to be (positive direction).

The holding position of the toner passage control means 3 in Table 1 is the coordinates of the holding position at one end where the tension of the toner passage control means 3 is loaded, that is, the distances from the origin O in the X and Y directions. Is shown. At this time, the holding position of the other end is such that the Y coordinate is the same as the one end, and the X coordinate is a minus coordinate with respect to the X coordinate of the one end. That is, the toner passage control means 3 is held at two points symmetrical with respect to the Y axis. For example, in the first embodiment, the coordinates (Xmm, Xmm, Ymm) is (1
9 mm, 3 mm) and (−19 mm, 3 mm).

In the first to fourth embodiments, the holding position (Xm
m, Ymm) are (19 mm, 3 mm) and (1
9mm, 5mm), (19mm, 7mm), (19m
m, 9 mm), and in Comparative Examples 1 to 3, (19 mm, 1 mm), (25 mm, 3 mm), (19
mm, 11 mm).

The radius of curvature R near the origin O of each of Examples 1-4 and Comparative Examples 1-3 at this time is 28, respectively.
19, 14, 10, 80, 48, 9 mm. The radius of curvature R can be measured by measuring the coordinates of three points near the origin O.

Under such specifications, the reference plane L
Is increased from 0, the density of the formed image at that time, and the contact position Cp of the spacer and the toner carrier 1 from the reference plane L to the toner carrier 1.
And the contact distance ΔCp was measured.

As shown in FIG. 7, the axial center distance Δe is measured by a scaled magnifying scope 21 through the axial center of the toner carrier 1 and a passage hole array area where two rows of toner passage holes are arranged. The measurement was performed by measuring the distance from a reference straight line that bisects S in the width direction.

The contact distance ΔCp is measured by rotating the toner carrier 1 for several seconds, stopping the rotation of the toner carrier 1, and applying a predetermined voltage to the control electrode 10 and the back electrode 6 for several seconds. Apply. After that, the toner carrier 1 is taken out from a casing (not shown) of the image forming apparatus,
The observation was performed by observing the surface with the magnifying scope 21 similarly.

That is, as shown in FIG. 8A, a toner layer is formed on the surface of the toner carrier 1, and the portion where the toner carrier 1 and the spacer are in contact is The layer is removed, leaving a linear contact mark 22 with a predetermined contact width. On the other hand, the application of the voltage causes a portion of the toner corresponding to the toner passage hole on the toner carrier 1 to be peeled off from its surface and landed on the recording paper.
Are formed on two surfaces of the print marks 21 and 21 having no toner layer so as to correspond to the toner passage holes. FIG.
As shown in FIG. 2B, the distance between the reference line 21a passing through the center of the two lines of print marks 21 and 21 and the center line 22a passing through the center of the contact width of the contact mark 22 is determined by the enlargement scope 21.
The contact distance ΔCp was measured by measuring according to.

Further, at this time, the state of the formed image was measured. As shown in FIG. 9, regarding the density of the formed image,
The density of the printed portion was measured with a Macbeth densitometer. Specifically, for the so-called solid image 25a having the highest density, the Macbeth density is 1.4 or more, and for the intermediate image half-tone image 25b,
A Macbeth density of 0.5 to 0.7 was defined as a high image quality condition. Further, the fog (that is, the stain of the non-printed portion 26 on the recording paper) was measured by using a Macbeth densitometer in the same manner as the density of the non-printed portion 26 on the recording paper.

The axial distance Δe, the contact distance ΔCp and the state of the formed image are shown in the lower part of Table 1 as experimental results. As can be seen from the experimental results, in the cases of Comparative Examples 1 and 2, the state where the fogging occurred and the state where the image density was low were shifted when the axial center distance Δe was 0.28 and 0.27 mm. Further, in the case of Comparative Example 3, fogging occurs over the entire area of 0 or more. As described above, in Comparative Examples 1 to 3, there is no value of the axial center distance Δe at which the formed image has high image quality.

On the other hand, in the first to fourth embodiments, the values of the axial center distance Δe are 0.25, 0.23, 0.2
When it is less than 1,0.19, fogging occurs, while the values of the axial center distances Δe are 0.33, 0.3, respectively.
When it is larger than 6, 0.44, 0.90, the image density becomes low. However, it can be seen that there is a range of values of the axial center distance Δe at which the formed image is in a high image quality state before the state where the fogging occurs to the state where the image density is low.

Therefore, the image forming apparatuses satisfy the relation of ΔCp = kΔe, and the constant k at that time satisfies the above equation (1.1 ≦ k ≦ 1.7). While the image can be of high quality, the constant k
However, it can be seen that the images formed in Comparative Examples 1 to 3 which do not satisfy the above-mentioned formulas cannot provide high quality images.

Incidentally, the target value of the predetermined range of the contact distance ΔCp for properly securing the interval ΔLk can be obtained based on the above-mentioned parameters constituting the image forming apparatus. That is, for example, when the radius of curvature R in the vicinity of the contact position Cp is 14 mm, the maximum value of ΔLk required to achieve high image quality without thinning the formed image is 6 μm. ΔCp ≦ 0.5 mm is a necessary condition.

On the other hand, as shown in FIG. 11, the distance between the rows of toner passing holes 5 and 5 is 0.3 mm, and the size of the toner passing holes 4 in the direction perpendicular to the direction in which the rows of toner passing holes 5 and 5 are arranged. Is 0.1 mm, the distance between the reference line passing through the center of the toner passage hole arrays 5 and 5 and the end of the spacer is 0.25.
Since it is necessary to be larger than 0.3 mm, ΔCp ≧
0.3 is a necessary condition. Therefore, the predetermined range of the target value of the contact distance ΔCp at this time is 0.3 ≦ ΔCp ≦ 0.5 °.

Accordingly, the toner passage control means 3
When assembling the toner carrier 1 with respect to, a constant k that satisfies the equation (1.1 ≦ k ≦ 1.7), for example, k =
As 1.4, based on the equation (ΔCp = kΔe) and the equation, the range of values that the axial center distance Δe should satisfy is: 0.21 ≦ Δe ≦ 0.36６ Therefore, by directly setting the axial center distance Δe to a size that satisfies the range of this equation, it is possible to easily realize an image forming apparatus with a high quality formed image.

[0066]

As described above, according to the first aspect of the present invention, the toner on the toner carrier is disposed between the toner carrier and the opposing member disposed opposite to the toner carrier. A toner passage control means for controlling the passage of toner through the toner passage holes based on an external image signal, and a toner passage control means for controlling the passage of toner through the toner passage holes; For an image forming apparatus having a spacer provided on the passage control means so as to be in contact with the toner carrier, the passage hole array region in which the toner passage hole array in the toner passage control means is arranged in the width direction. The contact distance ΔCp from the reference plane that passes through the straight line that divides equally and the straight line that passes through the center of the radius of curvature near the toner passage hole row and extends in the toner passage hole row direction from the reference position to the contact position of the spacer and the toner carrier is: It formed by uniquely determined in accordance with only the axial distance Δe from reference plane to the axis of the toner carrier. According to the second aspect of the present invention, the passage hole array area in which the toner passage hole array is provided in the toner passage control means is arranged in the width direction by two.
The contact distance ΔCp from the reference plane, which passes through the straight line that divides and extends in the direction in which the toner passes from the toner carrier toward the opposing member, to the contact position between the spacer and the toner carrier is from the reference plane to the axis of the toner carrier. Is determined solely in accordance with only the axial distance Δe, without changing other parameters such as the contact pressure between the spacer and the toner carrier and the curvature of the toner passage control means at the contact position. The contact distance ΔCp can be indirectly defined by the axial distance Δe. Therefore, the distance ΔLk between the toner carrier and the toner passage control means is determined by setting the axial distance Δe.
Can be easily and appropriately set, and the quality of the formed image can be improved.

According to the third aspect of the present invention, when the constant is k, two intervals of ΔCp = kΔe and 1.1 ≦ k ≦ 1.7 are satisfied. Can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an image forming apparatus according to an embodiment.

FIG. 2 is an enlarged vertical sectional front view of a main part of the embodiment.

FIG. 3 is a vertical sectional side view showing three operation states in an arbitrary toner passage hole of the embodiment.

FIG. 4 is a timing chart of voltages applied to a control electrode and a deflection electrode in the same embodiment.

FIG. 5 is a plan view showing an arrangement state of each electrode in the embodiment.

FIG. 6 is a schematic diagram illustrating a coordinate system of the image forming apparatus according to the present exemplary embodiment.

FIG. 7 is an explanatory diagram showing a measurement system of an axial center distance Δe.

FIG. 8 is an explanatory diagram showing a measurement system for a contact position ΔCp.

FIG. 9 is an explanatory diagram illustrating an image formed on a recording sheet.

FIG. 10 is a graph showing a relationship between a contact distance ΔCp and an interval ΔLk between a toner carrier and a toner passage control unit.

FIG. 11 is an enlarged plan view showing the vicinity of the toner passage hole array together with spacers.

FIG. 12 is a main part configuration diagram of a conventional image forming apparatus.

FIG. 13 is a configuration diagram illustrating an overall configuration of a conventional image forming apparatus.

FIG. 14 is a plan view showing an arrangement state of each electrode in the conventional example.

[Explanation of symbols]

 S Passage hole array region O Center of radius of curvature R Radius of curvature L Reference surface Cp Contact position ΔCp Contact distance Δe Axial distance k Constant 1 Toner carrier 2 Toner 3 Toner passage control means 4 Toner passage hole 5 Toner passage hole array 7 Opposite Member 12 Spacer

 ──────────────────────────────────────────────────の Continuation of the front page (71) Applicant 597063831 Owneds Brygga 13 421 57 Vestro Fround a Sweden (72) Inventor Taichi Ito 1006 Odakadoma, Kadoma City, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F-term (reference) 2C162AE25 AE31 AE47 AE56 AE74 CA02 CA12 CA24 2H029 DB04

Claims (5)

[Claims] 1. A toner carrier comprising a roller for carrying and transporting toner, an opposing member arranged opposite to the toner carrier, and disposed between the toner carrier and the opposing member; The toner carrier has a toner passage hole array in which toner passage holes for passing the toner toward the opposing member are arranged in parallel with the axis of the toner carrier. An image forming apparatus comprising: a toner passage control unit configured to control passage based on an external image signal; and a spacer provided on the toner passage control unit so as to contact the toner carrier. A straight line that bisects the passage hole array region where the toner passage hole array is disposed in the width direction, and a straight line that passes through the center of the radius of curvature near the toner passage hole array and extends in the toner passage hole array direction. From a reference plane passing through the contact distance ΔCp to the contact position of the spacer and the toner carrying member,
Axle distance Δe from the reference plane to the axis of the toner carrier
An image forming apparatus characterized in that the image forming apparatus is uniquely determined in accordance with only the image forming apparatus. 2. A toner carrier comprising a roller for carrying and transporting toner, an opposing member arranged opposite to the toner carrier, and disposed between the toner carrier and the opposing member; The toner carrier has a toner passage hole array in which toner passage holes for passing the toner toward the opposing member are arranged in parallel with the axis of the toner carrier. An image forming apparatus comprising: a toner passage control unit configured to control passage based on an external image signal; and a spacer provided on the toner passage control unit so as to contact the toner carrier. A reference surface extending in a direction in which the toner passes from the toner carrier to the opposing member through a straight line bisecting the passage hole array region in which the toner passage hole array is disposed in the width direction. An image forming method, wherein a contact distance ΔCp between the spacer and the contact position of the toner carrier is uniquely determined according to only an axis distance Δe from the reference plane to the axis of the toner carrier. apparatus. 3. The image forming apparatus according to claim 1, wherein when a constant is k, ΔCp = kΔe 1.1 ≦ k ≦ 1.7 is satisfied. 4. The image forming apparatus according to claim 1, wherein when a constant is k, ΔCp = kΔe 1.2 ≦ k ≦ 1.6 is satisfied. 5. The image forming apparatus according to claim 1, wherein when a constant is k, ΔCp = kΔe k = 1.4 is satisfied.