JPH07214815A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device which can form the multicolor images free from color-shift by a simple structure. CONSTITUTION:An image forming device supplies by a single toner carrying roller 14 the toners 16a, 16b and 16c, each of which has a different toner characteristic such as charged amount of electricity, charged electricity polarity, particle diameter, etc., and a different color, and controls the toner streams of the different colors simultaneously by an aperture electrode body 1 according to the toner characteristic, thereby forming color images on a supporting body.

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 which can be used in copying machines, printers, plotters, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, as an image forming method for forming a multicolor image, for example, JP-A-60-20371
0, JP-A-61-297480, JP-A-63-2114
58, JP-A-63-273163, JP-A-63-295.
An image of each color is sequentially developed on an image bearing member (photosensitive drum, photosensitive belt or intermediate transfer medium) using an electrophotographic developing device of a number corresponding to the number of colors as disclosed in each publication such as 665. Then, there is an image forming method in which this is transferred to a support.

Further, as one of the image forming apparatuses, an electrode having a plurality of openings (hereinafter referred to as apertures) is used, and a voltage is applied to the electrode based on image data, and toner particles are applied. Is controlled so that the toner can pass through the aperture to form an image on a support by the toner particles that have passed therethrough, and is disclosed in the specification of US Pat. No. 3,689,935.

This image forming apparatus comprises a flat plate made of an insulator, a continuous reference electrode formed on one surface of the flat plate, and a plurality of control electrodes insulated from each other formed on the other surface. , An aperture electrode body having at least one row of apertures formed through each of the control electrodes, and a means for selectively applying a potential between the reference electrode and the control electrode. A means for supplying the charged toner particles so that the flow of the toner particles passing through the aperture is modulated by the electric potential, and a means for relatively moving the support and the aperture electrode body to position the support in the particle flow path. It consists of and.

Also, for example, US Pat. No. 4,743,926.
Nos. 4,755,837, 4,780,733, and 4,847,796 disclose an image forming apparatus in which an aperture electrode body is arranged with a control electrode on the support side and a reference electrode on the toner supply side. There is.

In contrast, US Pat. No. 4,912,489
In the specification of the above U.S. Pat. It is described that it can be suppressed to about 1/4 as compared with the image forming apparatus.

Here, the "off" means a time when the toner particles are not adhered to the support, that is, a time when a blank portion of an image is formed, and conversely, "on" means that the support is on the support. It means a time point when a toner image is formed on.

Even in the image forming apparatus of such a system,
When a multicolor image is to be formed, a method is used in which a plurality of developing devices corresponding to the respective colors are arranged and the images of the respective colors are sequentially formed.

[0009]

However, in the conventional image forming apparatus as described above, when a multicolor image is to be formed, a plurality of developing devices must be installed for each color. Therefore, the device was large and expensive. Further, in this case, since images of respective colors are sequentially formed, it takes a long time to form an image, making it difficult to increase the speed. further,
Problems such as misalignment between the developing devices for each color and color misalignment due to transport system fluctuations such as skewing, slipping, and speed unevenness during transport of the image carrier or the support have occurred.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an image forming apparatus capable of forming a multicolor image with no color shift at a high speed with a simple structure. Has an aim.

[0011]

To achieve this object, the image forming apparatus of the present invention is provided with a plurality of types of toner having different characteristics in a single toner supply means, and these toners supplied by the toner supply means are supplied. And a toner flow control means for controlling the toner in accordance with the above characteristics.

[0012]

The image forming apparatus of the present invention having the above structure is
A single toner supply means is equipped with multiple types of toner,
The toner supplying means charges or magnetizes these toners so that they can be electromagnetically controlled to supply the toners to the toner flow control means, and these toners are electromagnetically controlled by the toner flow control means according to the characteristics of each toner. Control toner flow.

[0013]

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

FIG. 1 is a diagram showing an outline of the image forming apparatus of the present invention. A toner flow control means and an aperture electrode body 1 as an electrode body have a gap of 1 mm above the aperture electrode body 1 as a rear electrode. The cylindrical back electrode roller 22 is rotatably arranged on a chassis (not shown), and is configured to be able to convey the support 20 inserted into the gap. The back electrode roller 22 is configured so that at least its surface is conductive, and this conductive portion is grounded.

On the lower side of the aperture electrode body 1,
A toner supply device 10 as a toner supply means is arranged along the longitudinal direction of the aperture electrode body 1, and further, a fixing device is provided at the destination of the support body 20 conveyed by the back electrode roller 22. 26 are provided.

Next, the respective components will be described in detail. The toner supply device 10 includes a toner case 11 which also serves as a housing of the entire device, a supply roller 12, and a toner carrier roller 14 as a toner carrier. The toner layer control blade 18 is provided.

In the toner case 11, three types of toner, that is, a first type toner 16a and a second type toner 16 are provided.
b and the third type toner 16c are stored. The toner 16a of the first type, the toner 16b of the second type, and the toner 16c of the third type respectively have a volume average particle diameter,
At least one, preferably two, and more preferably two or more toner characteristics such as charge amount, charge polarity, cohesion degree, fluidity index, presence / absence of magnetic substance, and the like are different.

In the present embodiment, the first type toner 16a is yellow, has a volume average particle diameter of 15 μm, and has a negative polarity and a small charge amount. The second type toner 16b is magenta and has a volume average particle size. Particle size 6 μm, negative polarity and large charge amount, third type toner 16c of cyan color, volume average particle size 4 μm, positive polarity and large charge amount, and aggregation degree and fluidity index are used. The one with no big difference was used.

Here, the toner carrying roller 14 carries the toners 16a, 16b, and 16c and conveys them toward the aperture electrode body 1, and the supply roller 1
2 are toners 16 a and 1 with respect to the toner carrying roller 14.
6b and 16c are supplied.

The supply roller 12 and the toner carrying roller 14 are rotatably supported by the toner case 11 in the direction of the arrow shown in FIG. Further, the toner layer regulating blade 18
Is toner 16a carried on the toner carrying roller 14,
This is for adjusting the amounts of 16b and 16c to be uniform on the roller surface, and is pressed against the toner carrying roller 14.

In the aperture electrode body 1, as shown in FIG. 2, a plurality of apertures 6 are formed on an insulating sheet 2 made of polyimide having a thickness of 25 μm, and a control electrode 4 having a thickness of 1 μm is provided on the upper surface of each aperture 6. It was formed in.

The aperture 6 has an aperture 6a having a diameter of at least 16 μm or more so as to pass the toner 16a, and a diameter of at least 7 μm or more and not more than 14 μm so as to pass the toner 16b without passing through the toner 16a. There are three types, an aperture 6b and an aperture 6c whose diameter is at least 5 μm or more and is 14 μm or less so that the toner 16c does not pass through and the toner 16c passes through.
One column is provided at a fixed interval.

The control electrodes 4 provided around the apertures 6a, 6b, and 6c are the control electrodes 4 respectively.
Called a, 4b, and 4c.

As shown in FIG. 1, the aperture electrode body 1 has the toner carrying roller 1 at the aperture position of the insulating sheet 2 with the control electrode 4 facing the support body 20 side.
4, the aperture 6a is arranged by the toner carrying roller 14 on the upstream side in the toner conveying direction, and the aperture 6b and the aperture 6c are arranged on the downstream side.

A control voltage applying circuit 8 is connected between the control electrode 4 and the toner carrying roller 14.
The control voltage application circuit 8 applies a voltage of 0V or + 30V to the control electrode 4a, 0V or + 60V to the control electrode 4b, or 0V or -60V to the control electrode 4c based on the image signal. Is configured to.

Next, the operation of the image forming apparatus configured as described above will be described.

First, by rotating the toner carrying roller 14 and the supply roller 12 in the direction of the arrow shown in FIG. 1, the toners 16a, 16b and 16c sent from the supply roller 12 are rubbed against the toner carrying roller 14. . As described above, the toners 16a, 16b, and 16c sandwiched between the toner carrying roller 14 and the supply roller 12 and subjected to friction have the toner 16a having a small negative polarity and the toner 16b having a large negative polarity, and 16c, respectively. Can be charged with a large positive polarity. Further, the materials and compositions of the respective components of the toners 16a, 16b, and 16c, the materials and amounts of additives such as well-known charge control agents, external additives such as fluidizing agents, and internal additives, the toner carrying roller 1
4 and the supply roller 12 and the distance between the rotation center axes, and materials and rotation speeds of the toner carrying roller 14 and the supply roller 12 are appropriately selected.
It is possible to arbitrarily adjust the charging polarities and the charging amounts of b and 16c.

Toner 16 charged as described above
The particles a, 16b, and 16c are carried on the toner carrying roller 14 by the force (image force) by which the charged particles are attracted onto the conductor plate and the non-electrostatic adhesion force due to the Van der Waals force, the liquid bridging force or the like. It Here, the image force is 2 of the electric charge.
Since the toners 16b and 16c have a small particle size and a large charge amount, the toners 16b and 16c having a small particle size and a large charge amount receive a significantly larger image force than the toner 16a having a large particle size and a small charge amount. .

Toners 16a, 16b, and 1 carried
6c is thinned by the layer regulating blade 18,
The aperture electrode body 1 is rotated by the rotation of the toner carrying roller 14.
Be transported towards. Then, the toner carrying roller 14
The upper toner is rubbed by the insulating sheet 2 of the aperture electrode body 1 and supplied below the aperture 6.

Here, in accordance with the image signal, the control voltage applying circuit 8 is applied to the control electrode 4a corresponding to the yellow image portion.
To +30 V is applied. As a result, in the vicinity of the aperture 6a corresponding to the image portion, due to the potential difference between the control electrode 4a and the toner carrying roller 14, the control electrode 4a is formed.
More lines of electric force are formed toward the toner carrying roller 14. As a result, the negatively weakly charged toner 16
The a is subjected to an electrostatic force in the direction of high potential, and is drawn from the toner carrying roller 14 through the aperture 6a to the control electrode 4a side. The extracted toner 16a is further deposited on the support 20 supported by the back electrode 22 to form pixels.

On the other hand, the toner 16b, which is highly charged to the same polarity as the toner 16a, has a small particle size and a large amount of charge, so that it is constrained on the toner carrying roller 14 by a very strong image force, so that the control voltage is + 30V. With a weak electric field, the toner cannot be separated from the toner carrying roller 14 and pass through the aperture 6a to fly onto the support 20.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4a corresponding to the non-yellow image portion. As a result, since no electric field is formed between the toner carrying roller 14 and the control electrode 4a, the toner 16a on the toner carrying roller 14 does not receive the electrostatic force and therefore does not pass through the aperture 6a.

Similarly, according to the image signal, the control voltage applying circuit 8 is applied to the control electrode 4b corresponding to the magenta image portion.
Therefore, a voltage of +60 V is applied. As a result, in the vicinity of the aperture 6b corresponding to the image portion, due to the potential difference between the control electrode 4b and the toner carrying roller 14, the control electrode 4b is generated.
More lines of electric force are formed toward the toner carrying roller 14. As a result, the toner 16 that is strongly charged negatively
b is subjected to an electrostatic force in the direction of higher potential, and is drawn from the toner carrying roller 14 through the aperture 6a to the control electrode 4b side. The extracted toner 16a is further deposited on the support 20 supported by the back electrode 22 to form pixels.

On the other hand, since the toner 16a, which is charged to the same polarity as the toner 16b and has a small polarity, has a large particle size and a small charge amount, the image force is weak and the toner 16a tries to fly away from the toner carrying roller 14 toward the aperture 6b. However, the particle size is too large to pass through the aperture 6b. For the toner 16a that could not pass through the aperture 6b, the toner 16a on the aperture electrode body 1 and the toner 16a on the toner carrying roller 14
Since b and 16c are in contact with each other at the entrance portion of the aperture 6, the toner 16a which is about to be deposited at the entrance portion of the aperture 6 is swept away by the toner sequentially supplied by the toner carrying roller 14, so that the aperture 16a 6
It does not block b.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4b corresponding to the non-magenta image portion. As a result, since no electric field is formed between the toner carrying roller 14 and the control electrode 4b, the toner 16b on the toner carrying roller 14 does not receive the electrostatic force and therefore does not pass through the aperture 6b.

Further, a voltage of -60V is applied from the control voltage applying circuit 8 to the control electrode 4c corresponding to the cyan image portion. As a result, the aperture 6 corresponding to the image portion
A line of electric force directed from the toner carrying roller 14 to the control electrode 4c is formed in the vicinity of c due to the potential difference between the control electrode 4c and the toner carrying roller 14. As a result, the positively charged toner 16c receives an electrostatic force in the direction of a lower potential, passes through the aperture 6c from the toner carrying roller 14, and is drawn to the control electrode 4c side. The extracted toner 16c is further deposited on the support 20 supported by the back electrode 22 to form pixels.

A voltage of 0V is applied from the control voltage applying circuit 8 to the control electrode 4c corresponding to the non-cyan image portion. As a result, the toner carrying roller 14 and the control electrode 4
Since an electric field is not formed between the toner 16c and the toner c, the toner 16c on the toner carrying roller 14 does not receive the electrostatic force and therefore does not pass through the aperture 6c.

Further, the support 20 is fed by one pixel in the direction perpendicular to the aperture row while the pixels of each row are formed by the toners 16a, 16b and 16c on the surface thereof. Then, the toner image is formed on the entire surface of the support 20 by repeating the above process. After that, the formed toner image is fixed on the support 20 by the fixing device 26, whereby the toner 16 is fixed on the support 20.
A color image is formed by a, 16b, and 16c.

In the image forming apparatus configured as described above, since multicolored dots are simultaneously formed in the same row, high-speed image formation is possible, and the support 20
It is possible to perform good image formation without color misregistration due to defective conveyance of the support such as uneven conveyance speed, paper slip, and skew. For example, when a black character is formed with three colors of yellow, magenta, and cyan, the conventional image forming method is
Due to the defective conveyance of the support as described above and the misalignment of the developing device for each color, the contour line of the misaligned color was seen around the target black character, and it became unsightly.
In the image forming apparatus configured as described above, such a problem does not occur.

In the image forming apparatus constructed as described above, if the insulating toner is used, the toner carrying roller 14 is used.
The insulation between the control electrode 4 and the control electrode 4 is maintained, and the aperture 6 does not cause dielectric breakdown.

In the above process, the control electric field generated by the control electrode 4 is formed between the control electrode 4 and the inside of the aperture 6, and between the aperture 6 and the toner carrying surface of the toner carrying roller 14 which faces the aperture 6, so that the carrying is carried. Toner 1
Since the control electric field can be directly applied to 6a, 16b, and 16c, the control efficiency is good.

The supplied toners 16a, 16b,
And 16c receive mechanical force or the like due to sliding with the aperture electrode body 1 and enter the aperture 6 corresponding to the non-image portion, the electric field inside the aperture 6 does not pass through the aperture 6. Therefore, the controllability of the toner is good.

Further, since the toner carrying roller 14 and the aperture electrode body 1 are opposed to each other with the toner layer interposed therebetween, they can be arranged at a relatively short distance, so that the control voltage can be lowered and an inexpensive driving element can be provided. Can be used.

As shown in FIG. 1, the aperture electrode body 1 is installed with the control electrode 4 facing the support body 20, that is, the back side of the surface on which the control electrode 4 is formed. Since the surface of the insulating sheet 2 corresponding to is directed toward the toner carrying roller 14 side, even when the toner 16a, 16b, and 16c are not present on the toner carrying roller 14 due to a defect in the toner supply system, toner exhaustion, or the like. ,
The control electrode 4 and the toner carrying roller 14 do not come into contact with each other and electrically short-circuit, and the drive element is not destroyed.

Further, since the aperture electrode body 1 and the toners 16a, 16b, and 16c on the toner carrying roller 14 are in contact with each other at the entrance portion of the aperture 6, the toner 16a deposited at the entrance portion of the aperture 6, The toners 16b and 16c are washed away by the toner sequentially supplied by the toner carrying roller 14, so that the toners 16a and 16c are discharged.
b and 16c do not deposit and bridge to block the aperture 6.

The present invention is not limited to the embodiments described in detail above, and various modifications can be made without departing from the spirit of the invention.

For example, although the control voltage of the aperture corresponding to the non-image portion is set to 0V in the above embodiment, a potential having the same polarity as the charging polarity of various toners may be applied. In this case, an image with less fogging can be obtained.

In the above embodiment, the aperture electrode body is used as the toner flow control means, but it is also possible to use a mesh-shaped electrode body as described in the specification of US Pat. No. 5,036,341. Is.

The back electrode roller in the above embodiment is constructed so that at least its surface is electrically conductive and is electrically grounded, but this electrically conductive portion need not be grounded and is suitable. It is also possible to connect a different power supply and apply a direct current, an alternating current, or a voltage in which both are superimposed. Further, at least the surface of the back electrode roller may be made of a dielectric material, and this surface may be electrostatically charged by a method such as corona discharge or frictional charging.

Further, in the above-mentioned embodiment, the aperture electrode body is installed with the control electrode facing the support side, but it is installed with the control electrode facing the toner carrying roller side. Good.

In this case, if a sufficient amount of toner is present on the toner carrying roller, the toner layer can guarantee the insulating property between the control electrode and the surface of the toner carrying roller, but when the toner runs out, the control electrode and Since a short circuit occurs with the surface of the toner carrying roller and the driver IC for applying a voltage to the control electrode is destroyed, a toner sensor may be installed to replenish the toner before the toner runs out. The toner supply device or the cartridge in which the aperture electrode body and the toner supply device are integrated is exchanged, an appropriate insulating coat layer is provided on the control electrode, or a toner carrying roller is provided as shown in FIG. A suitable insulating spacer 13 is provided on 14 so that a short circuit does not occur between the control electrode and the surface of the toner carrying roller. Theft is more preferable.

[0052]

As is apparent from the above description, the image forming apparatus of the present invention can supply multicolor toners having different characteristics as toners by a single toner supply means. Can be simultaneously controlled by a single toner flow control means, so that multicolor printing can be performed simultaneously in a single printing process, and therefore, a simple configuration can be performed at high speed to form a multicolor image without color misregistration. It is possible to supply an image forming apparatus capable of performing the operation.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment embodying the configuration of an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration of an aperture electrode body used in the image forming apparatus of the present invention.

FIG. 3 is a diagram showing a configuration of an aperture electrode body and a toner carrying roller used in the image forming apparatus of the present invention.

FIG. 4 is a diagram showing a modified example.

[Explanation of reference numerals] 1 aperture electrode body 2 insulating sheet 4 control electrode 6 aperture 8 control voltage applying circuit 14 toner carrying roller 22 back electrode roller

Claims (6)

[Claims] 1. A single toner supply means is provided with a plurality of types of toner having different characteristics, and a toner flow control means is provided for controlling these toners supplied from the toner supply means according to the characteristics. A characteristic image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the toner flow control unit is composed of an electrode body having a large number of apertures through which the toner can pass. 3. The toner having a different charging polarity is used as the toner.
The image forming apparatus according to claim 1, wherein different types of toner are used, and the color of the toner is changed according to the polarity. 4. The toner having different outer diameters is used as the toner.
Two types of apertures having different diameters according to the toner particle size are formed on the electrode body while using different types of toner and different toner colors and toner charge amounts according to the toner particle size. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus. 5. The toner according to claim 4, further comprising a toner having a charging polarity different from that of the two types of toner having different particle diameters, and the three types of toner having different colors. The image forming apparatus described. 6. The image forming according to claim 4, wherein the electrode body is formed with an aperture having a large diameter so as to be positioned on the upstream side in the toner supply direction by the toner supply means. apparatus.