JPH10309821A - Image forming equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form dots of a good shape by a simple structure by setting the size of a toner passage hole in the direction perpendicular to the recording member transport direction larger as compared with the size in the recording member transport direction. SOLUTION: In a toner control member, the size W1 of multiple independent toner passage holes 31 in the direction perpendicular to the recording paper transport direction, that is, in the main scanning direction B, is set at a value higher than the size W2 in the subscanning direction A. And, the size W1 in the main scanning direction B is, when dots are formed on recording paper due to the adhesion of a toner passing the toner passage holes 31, set so that the length of the dot in the main scanning direction B and the length in the sub-direction A may be equal to each other. The toner that passes through the toner passage holes 31 while recording paper is transported, can prevent dots formed on the recording paper from being lengthened in the recording paper transport direction and thereby makes it possible to form dots of a good shape with a simple structure.

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 such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus of this type, a toner carrier for carrying a toner, a counter electrode facing the toner carrier, and a toner carrier and a counter electrode are disposed between the toner carrier and the counter electrode. A toner flight control member having a plurality of independent toner passage holes and a plurality of control electrode portions for controlling toner passage through each toner passage hole, wherein the control electrode portion of the toner flight control member responds to an image signal. By applying a voltage to the toner carrier, the toner on the toner carrier is selectively caused to fly, and the fluttered toner is transferred to the counter electrode side through the toner passage hole. 2. Description of the Related Art There is known an image forming apparatus which forms an image by being attached to a recording member conveyed in one direction and located between a counter electrode.

[0003]

However, according to the image forming apparatus having the above structure, the toner adheres to the recording member while the recording member is being conveyed. Further, since the electric field is weak at a portion where the control electrode does not exist between the toner passage holes (hereinafter, referred to as a non-opening portion), the toner does not easily fly toward the recording member corresponding to the non-opening portion.
For this reason, even if the toner flies in a circular shape from the toner passage hole, a long dot is formed in the recording member transport direction (hereinafter referred to as a sub-scanning direction) when the toner adheres to the recording member. There was a problem.

Further, since the toner does not easily fly toward the recording member corresponding to the non-opening portion, a linear image extending in a direction perpendicular to the sub-scanning direction (hereinafter referred to as a main scanning direction) is formed. In such a case, the toner adhering amount is large in the recording member portion corresponding to the toner passage hole, but the toner adhering amount is small in the recording member portion corresponding to the non-opening portion, and uneven density may occur in the main scanning direction. There was also a problem.

Here, in Japanese Patent Application Laid-Open No. 8-112293, a portion of a back electrode body, which is a counter electrode, is separated from an image recording medium at a portion facing the toner passage hole and faces a non-opening portion. Image formation in which concave annular portions and convex annular portions are alternately formed so as to approach an image recording medium at a portion, and the intensity of the electric field in the non-opening portion is made closer to the intensity of the electric field in the opening portion. An apparatus is disclosed. According to this device, the amount of toner adhered to the recording medium portion corresponding to the non-opening portion and the recording medium portion corresponding to the opening portion become substantially equal, and the above problem can be solved. However, it is difficult to align the unevenness of the surface of the back electrode body with the toner passage hole and the non-opening, and the accuracy of the unevenness for making the electric field uniform is also required. It is.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an image forming apparatus capable of forming dots of a good shape with a simple structure. It is to be.

It is a second object of the present invention to provide an image forming apparatus capable of eliminating the shading unevenness in the main scanning direction in addition to the first object.

[0008]

According to one aspect of the present invention, there is provided a toner carrier for supporting a toner, a counter electrode facing the toner carrier, and a counter electrode facing the toner carrier. A toner flight control member provided between the electrodes and having a plurality of toner passage holes independent of each other and a plurality of control electrode portions for controlling toner passage through each toner passage hole. By applying a voltage to the control electrode portion according to an image signal, the toner on the toner carrier is selectively fly, and the flying toner is passed through the toner passage hole to the opposite electrode side. In the image forming apparatus for forming an image by adhering onto a recording member conveyed in one direction and located between the toner flight control member and the counter electrode, the recording member having the toner passage hole Carrying The dimension perpendicular to the direction, is characterized in that it has set larger than the size of the recording member conveyance direction.

In this image forming apparatus, since the size of the toner passage hole in the direction orthogonal to the recording member conveyance direction is set to be larger than the size in the recording member conveyance direction, the toner passage hole passes through the toner passage hole. It is possible to prevent the formation of dots having a long shape in the recording member conveyance direction when the deposited toner adheres to the recording member.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the maximum diameter direction of the toner passage hole is oblique with respect to a direction orthogonal to the recording member transport direction, and in the recording member transport direction. Each toner passage hole is arranged in at least one row arranged in a direction perpendicular to the recording member conveyance direction such that a part of the toner passage holes adjacent in the direction perpendicular to the recording member conveyance direction are on the same line in the recording member conveyance direction. It is characterized by the following.

In this image forming apparatus, the maximum diameter direction of the toner passage holes is oblique to the direction perpendicular to the recording member transport direction, and at least one line arranged in the direction perpendicular to the recording member transport direction. Thus, some of the toner passage holes adjacent in the direction perpendicular to the recording member transport direction are on the same line in the recording member transport direction. With such an arrangement, when the dots are recorded on the recording member,
When the recording member is conveyed, there is no portion that does not completely oppose the toner passage hole other than the portion where the control electrode is not present between the toner passage holes. As a result, the toner flies in any direction in the direction orthogonal to the recording member conveyance direction, that is, in any portion in the main scanning direction, and it is difficult to generate a portion where the amount of adhered toner decreases. further,
It is also possible to realize the arrangement of the toner passage holes in which such a portion where the amount of attached toner is small is less likely to be generated in one line.

According to a third aspect of the present invention, the toner passage hole is
The other toner passage holes are arranged in a plurality of rows parallel to the direction orthogonal to the recording member conveyance direction, and are located on the same line in the recording member conveyance direction where the end of each toner passage hole in the direction perpendicular to the recording member conveyance direction is located. The toner passage holes are arranged so that a part of the toner passage hole exists.

In this image forming apparatus, the toner passage holes are arranged in a plurality of rows parallel to a direction perpendicular to the recording member conveyance direction, and the end of each toner passage hole in the direction perpendicular to the recording member conveyance direction is formed. Some of the other toner passage holes exist on the same line in the recording member conveyance direction. With such an arrangement, when the dot is recorded on the recording member, when the recording member is conveyed, the dot is completely opposed to the toner passage hole other than the portion where the control electrode is not present between the toner passage holes. There are no parts to do. As a result, the toner flies in any direction in the direction perpendicular to the recording member conveyance direction, that is, in the main scanning direction.
A portion where the amount of toner attached is reduced is less likely to occur. By arranging the toner passage holes in a plurality of rows, a space is formed around the toner passage holes, so that the shape of the toner passage holes can be easily changed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram illustrating a main part of the image forming apparatus according to the present embodiment. The image forming apparatus includes a sleeve-shaped toner carrier 1 that carries a toner, an opposing electrode member 2 as an opposing electrode arranged to face the toner carrier 1, a toner control member 3, and the like. The toner carrier 1 carries the toner supplied from the toner container 4 containing the toner on its surface and conveys the toner to a portion facing the toner control member 3. In the present embodiment, the negatively frictionally charged insulating toner is carried on the toner carrier 1 by electrostatic force.

The toner carrier 1 is grounded, and a flying electric field for causing the toner carried on the toner carrier 1 to fly toward the counter electrode member 2 between the toner carrier 1 and the counter electrode member 2. Are connected to a power supply 5 as a flying electric field forming means for forming the electric field. The power supply 5 applies a DC high voltage having a polarity opposite to the average charge polarity of the toner, for example, a voltage of plus 1.2 kV, to the opposite electrode member 2.

The toner control member 3 includes a toner carrier 1
A plurality of toner passage holes 31 and a ring-shaped control electrode formed around each of the plurality of toner passage holes 31 so as to control the flying of the toner from the toner carrier 1 to the counter electrode member 2. 32. The diameter of the toner passage holes 31 and the pitch between the toner passage holes 31 in a direction perpendicular to the conveying direction of the recording paper 6 as a recording member (hereinafter, referred to as a main scanning direction) are determined by the It is set according to the resolution. In the illustrated device, the resolution is 300d
In order to record an image of about pi, a toner passage hole 31 having a dimension described later is formed on a polyimide substrate as an insulating substrate.
The pitch is formed at an interval of 0.0845 mm. Further, ring-shaped control electrodes 32 that are electrically independent from each other are formed around each toner passage hole 31.
Each control electrode 3 of the toner carrier 1 and the toner control member 3
2, a power supply 7 for applying a control voltage generated based on image information to each control electrode 32 is connected.
The power supply 7 controls each control electrode 32 based on image information.
Are applied to each other. For example, a voltage of +300 V is applied to the control electrode corresponding to the image portion where the toner flies, and 0 V or a negative voltage is applied to the control electrode corresponding to the non-image portion where the toner does not fly.

In this image forming apparatus, the recording paper 6 is conveyed in the direction of arrow A and is sent between the counter electrode member 2 and the toner control member 3. The control electrode 3 corresponding to the image portion is fed while the toner is being fed horizontally over the toner control member 3.
When a voltage of +300 V is applied to 2, an electric field is formed by the potential difference between the control electrode 32 and the toner carrier 1, and the toner flies toward the toner passage hole 31. The toner that has passed through the toner passage hole 31 continues to fly toward the counter electrode member 2 due to the electric field between the counter electrode member 2 and the toner control member 3 and adheres to the recording paper 6. Thereby, an image is recorded. As described above, 0 V or a minus voltage is applied to the control electrode 32 corresponding to the non-image portion, and no electric field is formed between the toner carrier 1 and the control electrode 32, or An electric field is formed in a direction opposite to the direction in which the toner flies. Therefore, the toner does not fly in the non-image portion.

If the shape of the toner passage hole 31 provided in the toner control member 3 is circular, the toner adheres to the recording sheet while the recording sheet is being conveyed, and the control electrode 32 between the toner passage hole 31 is formed. (Hereinafter referred to as a non-opening portion), the electric field is weakened, and the toner hardly flies toward the recording member corresponding to the non-opening portion. Therefore, a dot having a short length in a direction orthogonal to the direction is formed.

Conventionally, since the toner does not easily fly toward the recording member corresponding to the non-opening portion, for example, when a linear image extending in a direction perpendicular to the recording paper conveyance direction is formed, the recording paper conveyance In some cases, density unevenness occurs in a direction perpendicular to the direction, and white stripes parallel to the recording paper conveyance direction may occur. If the diameter of the toner passage hole is increased so that such density unevenness does not occur, the resolution in the recording paper conveyance direction is undesirably reduced.

Therefore, in the toner control member 3 of the present embodiment, the dimension of the toner passage hole 31 in the direction orthogonal to the recording paper transport direction, that is, the dimension in the main scanning direction, is set in the recording paper transport direction (hereinafter, referred to as the sub-scanning direction). It is set to be larger than the size of. FIG. 2 is an enlarged view of the toner control member 3 used in the present embodiment. The direction of arrow A in the figure is the sub-scanning direction, and the direction of arrow B in the figure is the main scanning direction. In the toner control member 3, the dimension W1 of the toner passage hole 31 in the main scanning direction is set.
Is larger than the dimension W2 in the sub-scanning direction. In the illustrated toner control member 3, the size of the toner passage hole 31 in the sub-scanning direction is set to 0.13 in order to realize a resolution of 300 dpi.
It is set to 5 mm. Then, the dimension W in the main scanning direction
1 is set so that the length of the dot in the main scanning direction is equal to the length of the dot in the sub-scanning direction when a dot is formed on the recording paper due to the adhesion of the toner passing through the toner passage hole 31. . The pitch Ph of each toner passage hole 31 in the main scanning direction is 0.0845 m as described above.
m.

As described above, when the size of the toner passage hole 31 in the direction orthogonal to the recording paper conveyance direction is set to be larger than the size in the recording paper conveyance direction, the toner passage hole 31 is conveyed while the recording paper is being conveyed. Even if the toner that has passed through the recording paper adheres to the recording paper, it is possible to prevent the dots formed on the recording paper from becoming long in the recording paper conveyance direction. Therefore, it is possible to form a dot having a good shape with a simple structure.

Further, in the toner control member 3 of the illustrated example, each toner passage hole 31 is arranged such that the maximum radial direction of each toner passage hole 31 is oblique to the direction orthogonal to the recording member conveyance direction. I have. Each toner passage hole is arranged in at least one row arranged in the main scanning direction such that a part of the toner passage holes 31 adjacent in the main scanning direction are on the same line in the sub-scanning direction. Specifically, the toner passage holes 31 are arranged in a line in the main scanning direction.
A part of the toner passing holes 31 adjacent to the toner passing holes 31 in the main scanning direction is located on the same line in the sub-scanning direction where the end of the toner passing holes 31 in the main scanning direction is located in one row of the array. Each toner passage hole is arranged to be present. With such an arrangement, when the dots are recorded on the recording paper, there is no portion that does not completely oppose the toner passage hole that is a portion other than the non-opening portion when the recording paper is conveyed. As a result, the toner flies in any portion in the main scanning direction, and a portion in which the amount of toner adhered is less likely to occur. Therefore, density unevenness can be prevented. Further, by disposing the toner passage hole 31 obliquely, the toner passage hole 3 in which such a portion where the amount of adhered toner is reduced is less likely to occur.
It is also possible to realize one arrangement by one line. When the toner passage holes 31 are arranged on one line in this manner, compared with the case where the toner passage holes 31 are arranged on a plurality of lines,
The writing timing in each toner passage hole 31 can be easily controlled.

FIG. 3 is an enlarged view showing a modification of the toner control member 3. As shown in FIG. The direction of arrow A in the figure is the sub-scanning direction, and the direction of arrow B in the figure is the main scanning direction. This toner control member 3
Also, in the main scanning direction dimension W1 of the toner passage hole 31
Is larger than the dimension W2 in the sub-scanning direction, and a dot having a good shape can be formed. Further, the toner control member 3 is configured such that the toner passage holes 31 are parallel to the main scanning direction.
The other toner passage holes 31 are arranged in a row, and a part of the other toner passage holes 31 is present on the same line in the sub-scanning direction where the end of each toner passage hole 31 in the direction orthogonal to the recording member conveyance direction is located.
Each toner passage hole is arranged. The toner passage holes 31 may be arranged in three or more rows in parallel with the main scanning direction. When dots are formed by using this toner control member, when the portion of the recording paper conveyed in the direction of arrow A where the toner is to be attached faces the toner passage hole, it is applied to the control electrode of the toner passage hole. The voltage application timing to the control electrode is controlled so that the above-mentioned voltage of the image portion, for example, plus 300 V is applied.

With this arrangement, when the dots are recorded on the recording paper, the recording paper is not confronted by the toner passage holes 31 other than the non-opening portions when the recording paper is conveyed. Parts are gone. As a result, the toner flies in any portion in the main scanning direction, and a portion in which the amount of toner adhered is less likely to occur. Therefore, density unevenness can be prevented. Also,
In the example shown in the drawing, by arranging the toner passage holes 31 in a plurality of rows, a space is formed around the toner passage holes 31, so that the shape of the toner passage holes 31 can be easily changed. Further, in the illustrated example, a direction in which the maximum radial direction of the toner passage hole 31 is orthogonal to the recording member conveyance direction,
That is, the toner passage holes are arranged so as to be parallel to the main scanning direction. When the maximum diameter direction of the toner passage hole is disposed so as to be oblique to the main scanning direction as in the toner control member of FIG. It may be formed obliquely to the scanning direction. When the dots are formed obliquely as described above, the contours of the dots adjacent in the main scanning direction are more conspicuous than in the case where the maximum radial direction of the dots is formed parallel to the main scanning direction. In the example of FIG. 3, the maximum diameter direction of the toner passage hole is parallel to the main scanning direction,
The dots are formed such that the maximum radial direction of the dots is parallel to the main scanning direction, and the irregularities are less likely to occur.

In this embodiment, an example has been described in which an insulating toner is used as the toner and charge is applied to the toner by frictional charging. However, a conductive toner is used as the toner and the toner carrier is Charge may be provided to the toner by charge injection from the toner.

[0026]

According to the first to third aspects of the present invention, there is an excellent effect that it is possible to form dots of a good shape with a simple structure.

Further, according to the second and third aspects of the invention, there is an excellent effect that the shading in the main scanning direction can be eliminated.

In particular, according to the invention of claim 2, since the arrangement of the toner passage holes can be realized by one line, there is also an effect that control of voltage application to each control electrode is simplified.

According to the third aspect of the present invention, since a space is formed around the toner passage hole, there is also an effect that the shape of the toner passage hole can be easily changed to a preferable shape.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a schematic configuration of an image forming apparatus according to an embodiment.

FIG. 2 is an enlarged view of a toner control member of the image forming apparatus.

FIG. 3 is an enlarged view showing a modified example of the toner control member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner carrier 2 Counter electrode member 3 Toner control member 31 Toner passage hole 32 Control electrode 4 Toner container 5 Power supply 6 Recording paper 7 Power supply

Claims (3)

[Claims] A toner carrying member for carrying a toner, a counter electrode facing the toner carrying member, a plurality of toner passage holes provided between the toner carrying member and the counter electrode and independent of each other. A toner flight control member having a plurality of control electrode units for controlling the passage of toner through the toner passage hole, and by applying a voltage to the control electrode unit of the toner flight control member in accordance with an image signal, The toner on the toner carrier is selectively caused to fly, and the flying toner is transferred to the counter electrode side through the toner passage hole, and is located between the toner flight control member and the counter electrode. An image forming apparatus for forming an image by adhering on a recording member conveyed in one direction, wherein a size of the toner passage hole in a direction orthogonal to the recording member conveyance direction is compared with a size in the recording member conveyance direction. hand An image forming apparatus characterized by being set large. 2. The image forming apparatus according to claim 1, wherein a maximum diameter direction of the toner passage holes is oblique to a direction orthogonal to the recording member conveyance direction and is arranged in a direction orthogonal to the recording member conveyance direction. An image characterized by arranging each toner passage hole in such a manner that at least one of the toner passage holes adjacent in the direction orthogonal to the recording member conveyance direction is located on the same line in the recording member conveyance direction. Forming equipment. 3. The image forming apparatus according to claim 1, wherein the toner passage holes are arranged in a plurality of rows parallel to a direction perpendicular to the recording member conveyance direction, and each toner passage hole is perpendicular to the recording member conveyance direction. An image forming apparatus, wherein each toner passage hole is arranged such that a part of another toner passage hole exists on the same line in the recording member conveyance direction where an end of the toner passage hole is located.