JPH05193182A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To provide an image forming apparatus uniformizing the supply amount of toner over the entire width of an aperture, that is, the density of an output image. CONSTITUTION:Since the width of a toner feed belt 26 is sufficiently larger than the width of a row of apertures 6, the effect of the parts weak in tension at both end parts of the toner feed belt 26 does not appear and a toner cloud uniform over the entire width of the rows of the apertures 6 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a printer,
The present invention relates to an image forming apparatus that can be used for plotters, facsimiles, and the like.

[0002]

2. Description of the Related Art Conventionally, an image recording apparatus for obtaining an image on a support by controlling the passage of toner particles through an aperture by applying an image signal to an electrode having an aperture has been proposed in US Pat. No. 3,689,935. Has been done. In this proposal, it is composed of a reference electrode that is continuous on one side with a layer of an insulator interposed between it and a plurality of control electrodes that are insulated from each other on the other side. Each insulated plurality of control electrodes penetrates three layers. An aperture electrode body having at least one row of apertures, means for selectively applying a potential between the control electrode and the reference electrode, and the applied potential modulates the flow of toner particles through the aperture. It is composed of means for projecting electrically charged particles and means for positioning the support in the particle flow path by the relative movement of the support and the aperture electrode body. In this method, as a means for supplying the charged toner particles to the vicinity of the aperture, a method of conveying the charged toner in a cloud shape by a vibrator has been proposed.

[0003]

However, even if an endless toner conveying belt is to be uniformly tensioned by a plurality of rollers, the restraining conditions are different, so that the tension is weaker at both ends than at the center of the belt.

Therefore, even if the surface of the toner conveying belt facing the aperture is vibrated by the vibrating means, the vibration at both ends is weaker than the center of the belt for the above reason, and the toner cloud is less supplied to both ends of the aperture. For,
There is a problem that the density of the output image is high at the center and light at both ends.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus in which the toner supply amount is made uniform over the entire width of the aperture, that is, the density of an output image is made uniform. I am trying.

[0006]

To achieve this object, the image forming apparatus of the present invention controls the passage of the charged toner through the aperture by applying an image signal to an electrode having an aperture. An image forming apparatus for forming an image on a support provided on the opposite side with a toner supply source by a cloud and an electrode with an aperture interposed therebetween, wherein a toner supply unit is arranged so that one surface faces the aperture,
The toner transport belt has a width sufficiently larger than the width of the aperture train, and a vibrating means for vibrating the surface of the toner transport belt facing the aperture.

[0007]

According to the present invention having the above-mentioned structure, the vibrating means vibrates the surface of the toner conveying belt having a width sufficiently larger than the width of the aperture array, the surface facing the aperture, and supplies the toner to the aperture array.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an image forming apparatus 100 according to an embodiment of the present invention. As shown in detail in FIG. 2, the aperture electrode body 1 has a reference electrode 3 on the toner supply source side of the insulating layer 2 and a control electrode 4 on the support side.
A large number of apertures 6 penetrating the reference electrode 3, the insulating layer 2, and the control electrode 4 are formed in a row in the width of the support. In FIG. 1, the support 1 is provided to the left of the image forming apparatus 100.
A cassette 50 for storing 0, a half-moon roller 51 for supplying the supports 10 one by one, a support supply roller 52 for sending out the supports 10 and a chute 53 are arranged in the downstream portion.

On the downstream side, on the control electrode side of the aperture electrode body 1, the support carrier roller 14, the sensor 57, and
A back electrode 11 is disposed in contact with the back surface of the support body 10, and each control electrode 4 is connected to a control voltage drive circuit 8 that generates a voltage according to an image signal. The back electrode 11 is connected to a negative high voltage power supply 12.

On the side of the reference electrode of the aperture electrode body 1, a toner transport belt 26 is wound between the drive roller 20 and the backup roller 24, and the back side of the transport belt facing the aperture electrode body has an elliptical cross section. The cam roller 27 is provided with the static elimination brushes 37 on the upstream side thereof. These are housed in the toner case 21 together with the toner 22 accumulated near the supply roller 23, and a carrying roller 30 that is in contact with the supply roller 23 and has a clearance of 0.1 to 0.4 mm with the toner conveying belt 26. . The supply roller 23 has a sponge or the like, and the supporting roller 30 has a resin surface.

The width of the toner conveying belt 26 is as shown in FIG.
It is necessary to make it sufficiently larger than the width of the aperture row as shown in. The specific amount L is at least several millimeters, preferably 10 millimeters or more.

Further downstream, the fixing device 13 and the chute 5 are provided.
4, a discharge roller 55, and a tray 56 are arranged.

The operation of the above structure will be described in detail below.

The support 10 housed in the cassette 50 is
Half moon roller 51 feeds out one by one and shoots 5
3 is guided by the supporting member feeding roller 52 and is conveyed to the supporting member conveying roller 14. When the tip of the support 10 is detected by the sensor 57, the toner transport belt 26 rotates between the backup roller 24 and the drive roller 20 by the rotation of the drive roller 20 in the arrow direction, and the toner 22 is rotated by the rotation of the supply roller 23 in the arrow direction. After being rubbed by the carrying roller 30 to be positively triboelectrically charged, the toner is carried on the toner carrying belt 26 by electrostatic coating with a high voltage power source.

The carried toner is conveyed toward the surface facing the aperture electrode, but the conveying belt 26 is discharged from the back side of the toner conveying belt 26 on the upstream side of this position by the discharging brush 37. Since the cam roller 27 is rotating at the position of the surface facing the aperture electrode, the surface of the toner carrying belt 26 vibrates. Therefore, the toner transport belt 26
The toner carried by the toner is subjected to a force by the vibration acceleration of the toner conveying belt 26, is released from the image force, the van der Waals force, and the adhesion force such as the electrostatic force with the toner conveying belt 26, and soars to form a toner cloud. ..

At this time, since the width of the toner conveying belt 26 is sufficiently larger than the width of the row of apertures 6, the effect of the weak tension at both ends of the toner conveying belt 26 does not appear, and the entire width of the row of apertures 6 does not appear. A uniform toner cloud is formed.

On the other hand, when a negative voltage is applied to the control electrode 4 according to an image signal from a storage means (not shown), the aperture 6 of the applied control electrode 4 goes from the back surface to the front surface of the aperture 6. The toner 22 that has a line of electric force and is positively charged is drawn from the back surface of the aperture 6 to the front surface, and is further scattered onto the support by the flying electric field formed by the back electrode 11. , Held to form the image portion. By applying the same potential or a positive voltage as the reference electrode 3 to the control electrode 4 of the aperture 6 corresponding to the non-image part, the flying electric field by the back electrode 11 is shielded, or from the front surface inside the aperture 6. The passage of the toner 22 through the aperture 6 is suppressed by forming an electric force line toward the reference electrode 3 on the back surface. By repeating this process while transporting the support 10, a toner image is formed on the entire surface of the support 10.

As described above, since the uniform toner cloud is formed over the entire width of the row of the apertures 6, a toner image having a uniform density is formed on the entire surface of the support 10.

The support on which the toner image is formed is the fixing device 1.
After passing through 3, the image is fixed on the support 10. Further, it is guided by the chute 54 and discharged onto the tray 56 by the discharge roller 55.

Further, the present invention is not limited to the above-mentioned embodiment and can be modified within a range not departing from the gist thereof.

[0022]

As is clear from the above description,
According to the present invention, since the width of the toner conveying belt is sufficiently larger than the width of the row of apertures, the effect of weak tension at both ends of the toner conveying belt does not appear, and a uniform toner cloud is formed over the entire width of the row of apertures. Thus, a toner image having a uniform density is formed on the entire surface of the support.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment embodying the present invention.

FIG. 2 is a perspective view showing details of an aperture electrode body.

[Explanation of symbols]

 1 Aperture electrode body 2 Insulating layer 3 Reference electrode 4 Control electrode 6 Aperture 8 Control voltage drive circuit 10 Support 11 Back electrode 12 High voltage power supply 22 Toner 26 Toner conveying belt 27 Cam roller

Claims (1)

[Claims] 1. A support provided on the opposite side of an electrode provided with an aperture so as to control the passage of the charged toner through the aperture by applying an image signal to the electrode, and to sandwich the toner supply source by the toner cloud and the electrode with the aperture. In an image forming apparatus for forming an image on a toner conveyance unit, a toner supply unit includes a toner conveyance belt arranged so that one surface faces the aperture, and a vibration unit that vibrates a surface of the toner conveyance belt opposed to the aperture. An image forming apparatus, wherein the width of the toner conveying belt is sufficiently larger than the width of the aperture array.