JP2002046258A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus in which adverse effect on the electrostatic attraction of a recording medium or the imaging is eliminated by eliminating uneven charging of a carrying means. SOLUTION: The imaging apparatus comprises a carrying belt 20 for carrying a recording paper P while attracting to the carrying plane A electrostatically, means 1 for supplying ink particles toward the recording paper P under carriage in order to image on the recording face of the recording paper P, means 4 disposed on the upstream side of the carrying passage of the ink supply means 1 and charging the carrying belt 20 to attract the recording paper P, a cleaning means 5 disposed on the downstream side of the carrying passage of the ink supply means 1 and removing ink adhering to the carrying plane A of the carrying belt 20, and a neutralization brush 7 disposed in the carrying passage between the cleaning means 5 and the charging means 4 and removing excess charges on the carrying plane A.

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 for forming an image on a recording surface of a recording medium by supplying ink particles to the recording medium to be conveyed.

[0002]

2. Description of the Related Art The prior art of such an image forming apparatus will be described with reference to FIG. In FIG. 3, an image forming apparatus includes an ink supply unit 1 that forms a color image by supplying ink particles to a recording paper P (corresponding to a recording medium).
Transport means 2 for electrostatically attracting and transporting recording paper P
A recording paper supply unit 3 for supplying the recording paper P to the ink supply unit 1; a charging unit 4 for charging the transport unit 2; and cleaning of the ink adhered to the transport surface of the transport unit 2. And a discharging unit 6 for discharging the recording paper P on which an image is formed. The ink supply unit 1 includes an ink cartridge 10 that ejects (one mode of supply) cyan, magenta, and yellow ink particles sequentially from an upstream side along a transport path.
C, 10M, and 10Y are provided. Each of the ink cartridges 10C, 10M, and 10Y is provided with supply ports 11C, 11M, and 11Y for discharging ink particles. Each ink cartridge 10C, 10M, 10Y
Accordingly, the two-dimensional image can be formed on the recording paper P by conveying the recording paper P in the direction of the arrow S in FIG. 3 while forming the image one line at a time.

[0005] The conveying means 2 includes a conveying belt 20 and conveying rollers 21, 22, 23 and 24. The transport belt 20 is formed of a material that is easily charged, and transports the recording paper P to the transport surface A facing the ink supply unit 1 in a state of being electrostatically attracted.

The recording paper supply means 3 includes a magazine 30 for accommodating a plurality of recording papers P in a stacked state, and a supply roller 31 for supplying the recording papers P from the magazine 30 toward a transport path.
And a timing roller pair 32 for feeding the recording paper P toward the ink supply means 1 at an appropriate timing.

The charging means 4 comprises a charging roller 4 made of conductive rubber.
0 and a high-voltage transformer 41. The charging roller 40 is located at a position facing the transport roller 21. The transport roller 21 has a high resistance, so that the transport belt 20
Is easily charged. As a result, the transport belt 20 is charged and the recording paper P sent from the recording paper supply means 3 is electrostatically attracted.

The cleaning means 5 removes ink adhered to the transport surface of the transport belt 20 by the cleaning roller 55 to perform cleaning, and a bias voltage may be applied in order to facilitate the removal of the ink. The discharge unit 6 includes a discharge roller pair 60 that discharges the recording paper P on which an image is formed. Discharge roller pair 60
Also function as a fixing roller pair.

[0007]

By the way, even after the conveyor belt 20 is charged by the charging means 4, the conveyor belt 20 may be frictionally charged by contact with each of the conveyor rollers 21 to 24. In this case, extra charges are generated by the transfer belt 2.
0 is added. As a result, charging unevenness occurs on the surface of the transport belt 20, and there is a possibility that poor suction of the recording paper P occurs. In addition, when the ink particles are charged, there is a problem that a desired image is not formed because the ink particles are affected by uneven charging.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to remove an uneven charging of a conveying means so as not to adversely affect the electrostatic attraction of a recording medium and the formation of an image. It is to provide.

[0009]

In order to solve the above-mentioned problems, an image forming apparatus according to the present invention comprises a conveying means for conveying a recording medium in a state where the recording medium is electrostatically attracted to a conveying surface; By supplying it to the recording medium,
An ink supply unit for forming an image on a recording surface of the recording medium, and an ink supply unit provided upstream of a transport path of the ink supply unit;
A charging unit that charges the transport unit and electrostatically attracts the recording medium to the transport surface, and is provided downstream of a transport path of the ink supply unit, and after the recording medium is separated from the transport unit, A cleaning unit for removing ink attached to the transport surface of the transport unit; and a charge removing unit provided on a transport path between the cleaning unit and the charging unit for removing excess charge on the transport surface. It is characterized by the following. According to this configuration,
The recording medium is conveyed while being electrostatically attracted to the conveying surface of the conveying means. Before the recording medium is electrostatically attracted, the conveying means is charged by the charging means. As a result, the recording medium is reliably attracted to the transport surface. Then, ink particles are supplied to the recording medium by the ink supply means, whereby an image is formed. After the image is formed, the recording medium is separated from the transport unit, and the ink attached to the transport surface is removed by the cleaning unit. Then, after the cleaning of the transfer surface, before the charging by the charging unit is performed, the excess charge generated by frictional charging or the like is removed by the discharging unit. Therefore, it is possible to provide an image forming apparatus that eliminates charging unevenness of the conveying unit and does not adversely affect electrostatic attraction of a recording medium and image formation.

In a preferred embodiment of the present invention, the charge removing means is arranged in the vicinity of the charging means. Since the extra charge is generated in the middle of the transport path, the charge unevenness is removed more effectively by arranging the charge eliminating means near the charging means, that is, immediately before the charging by the charging means is performed. be able to.

In another preferred embodiment of the present invention, the charge removing means is a charge removing brush in contact with or in proximity to the transport surface. Use of a charge elimination brush as a charge elimination means has a cost advantage. Since the discharging brush is arranged downstream of the cleaning means, there is no possibility that ink particles adhere to the tip of the brush and become dirty.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the configuration of an image forming apparatus, and FIG. 2 is a diagram illustrating the principle of dielectric polarization. <Configuration of Image Forming Apparatus> In FIG. 1, an image forming apparatus includes an ink supply unit 1 for forming a color image by supplying ink particles to a recording sheet P (corresponding to a recording medium). Transport means 2 for electrostatically attracting and transporting; recording paper supply means 3 for supplying recording paper P to ink supply means 1; charging means 4 for charging transport means 2; The cleaning unit 5 includes a cleaning unit 5 for cleaning and removing ink adhered to the conveying surface of the unit 2 and a discharging unit 6 for discharging the recording paper P on which an image is formed. Cleaning means 5
A charge removing brush 7 functioning as a charge removing unit is provided in a transport path between the charging unit 4 and the charging unit 4. The ink supply means 1 is provided with ink cartridges 10C, 10M, and 10Y for discharging (one mode of supply) the cyan, magenta, and yellow ink particles in order from the upstream side along the transport path. Each ink cartridge 10C, 10M,
10Y has a supply port 11 for discharging ink particles.
C, 11M, and 11Y are provided. Supply port 11C,
Positive (+) charged ink particles are ejected from 11M and 11Y. Each ink cartridge 10C, 10M, 1
0Y, the recording paper P is formed while forming an image line by line.
Is transported in the direction of arrow S in FIG.
A two-dimensional image can be formed.

The conveying means 2 includes an endless conveying belt 20,
Transport rollers 21, 22, 23 and 24 are provided.
The conveyor belt 20 is formed of a material that is easily charged,
The recording paper P is mounted on the transport surface A facing the ink supply unit 1 in a state where the recording paper P is electrostatically attracted. The transport belt 20 is preferably one selected from the group consisting of a polyimide resin and a polyvinylidene fluoride resin.

The recording paper supply means 3 includes a magazine 30 for accommodating a plurality of recording papers P in a stacked state, and a supply roller 31 for supplying the recording papers P from the magazine 30 toward a transport path.
And a timing roller pair 32 for feeding the recording paper P toward the ink supply means 1 at an appropriate timing.

The charging means 4 includes a charging roller 4 made of conductive rubber.
0, a high-voltage transformer 41, and a polarization roller 42 (ground roller). The charging roller 40 and the polarization roller 42 are located at positions facing the transport roller 21.
The transport roller 21 has high resistance, thereby facilitating charging of the transport belt 20. Polarizing roller 4
2 is grounded, thereby causing the recording paper P to generate dielectric polarization.

The cleaning means 5 cleans ink adhered to the surface of the transport belt 20 by the cleaning web 50. The cleaning means 5 includes an opposing roller 51 facing the transport roller 23, a supply roller 52, and a take-up roller 53. Have. The discharge unit 6 includes a discharge roller pair 60 that discharges the recording paper P on which an image is formed. The discharge roller pair 60 also functions as a fixing roller pair.

To ensure that the recording paper P is electrostatically attracted to the conveyor belt 20, the conveyor belt 20 is charged by the charging means 4. Because the recording paper P has various sizes and has a curl habit,
To ensure adsorption, it is necessary to give a considerable amount of charge. Further, as described later, both the recording surface of the recording paper P and the transport surface A of the transport belt 20 are negatively charged.

Next, the charge removing brush 7 which is a feature of the present invention will be described. The recording paper P is electrostatically attracted by charging the transport belt 20 by the charging means 4. This ensures that the recording paper P is adsorbed, but the charging of the conveyor belt 20 is not limited to the charging means 4. For example, since the transport belt 20 is driven by the transport rollers 21 to 24, the transport belt 20 is also charged by friction between the transport belt 20 and the transport rollers 21 to 24.
Therefore, there is a possibility that the transport belt 20 is charged even in a process after charging by the charging unit 4. Due to such charging, extra charges accumulate on the transport belt 20 and cause uneven charging.

When charging unevenness occurs, when the recording paper P is adsorbed, there is a possibility that the recording paper P cannot be reliably adsorbed. Further, when the ink particles are charged as in the present embodiment, there is a possibility that the ink particles are not ejected straight due to uneven charging, which may lower the quality of an image formed.

Therefore, in the present invention, the neutralizing brush 7 is used.
Are arranged to remove extra charges on the transport surface of the transport belt 20. Thereby, charging unevenness is eliminated. The static elimination brush 7 is provided on a transport path between the cleaning unit 5 and the charging unit 4, but is disposed downstream of the position where the transport roller 24 is disposed, in particular, in the vicinity (just before) the charging unit 4. Is preferred. As a result, the charging unevenness can be removed immediately before the charging unit 4, and the charging unit 4 can perform charging without unevenness.

The neutralizing brush 7 has fine metal fibers, amorphous fibers, carbon fibers, and the like provided at the tip thereof in the width direction of the transport belt 20. By bringing the metal fibers into contact with or close to the transport surface of the transport belt 20, excess charges can be removed. Instead of the neutralizing brush 7, a non-contact neutralizing means for causing ions of opposite polarity to fly to a transport surface or the like may be employed, but the neutralizing brush 7 is advantageous in terms of cost. <Principle of Electrostatic Attraction and Supply of Coloring Material> Next, referring to FIG.
And the principle of supplying a color material to the device will be described. In the image forming apparatus according to the present invention, a mixture of the solvent and the ink particles 12 a ionized in opposite polarities is used as the coloring material 12. As a configuration for supplying the ink particles 12a toward the recording paper P, for example, ink is ejected and supplied, and various methods can be selected to control the traveling direction and speed of the ink. . For example, the ink can be continuously ejected and vibrated to form the ink into particles, or the ink particles 12a can be ejected in a droplet state as in the present embodiment.

The polarizing roller 42 is disposed so as to contact the recording surface of the recording paper P. The polarizing roller 42 is arranged so that the recording surface of the recording paper P has the opposite polarity to the ink particles 12a. Is dielectrically polarized. And charging means 13
(Power supply) applies the ink particles 12
It is charged to the same polarity as a. Further, the transport belt 20 is charged by the charging roller 40 to have a polarity opposite to that of the ink particles 12a. In the present embodiment, the transport belt 20 and the recording surface of the recording paper P are negatively charged, and the ink particles 12a are positively charged. However, the polarity may be reversed. <Operation of Image Forming Apparatus> Next, the operation of the image forming apparatus according to the present embodiment will be described. First, the recording paper P is supplied from the magazine 30 by the one-sheet supply roller 31. When it is confirmed that the recording paper P does not exist at the position of the ink supply means 1, the timing roller pair 32 is driven to send out the recording paper P toward the ink supply means 1. On the other hand, the transport belt 20 is circulated by transport rollers 21 to 24, and the transport surface of the transport belt 20 is charged by the charging unit 4. At a position immediately after the conveyance belt 20 is charged, the recording paper P is conveyed while being sandwiched between the conveyance roller 21 and the polarization roller 42.

Next, the recording paper P is sent to the ink supply means 1 and a desired image is formed on the recording surface. The recording paper P on which the image has been formed is separated from the transport surface A and discharged to the outside of the apparatus main body by the discharge roller pair 60. In order to easily separate the recording paper P from the transport surface A, an ink supply unit 1
Another static elimination means may be provided on the downstream side of. On the other hand, the transport belt 20 is driven to circulate and sent to the cleaning unit 5, and the ink adhered to the transport surface A is removed by the cleaning web 5.
Removed by 0. Then, the excess charge accumulated on the transport surface of the transport belt 20 is removed by the charge removing brush 7 to remove uneven charging. With the charging unevenness removed,
The conveyor belt 20 is charged again by the charging means 4, and the newly fed recording paper P is electrostatically attracted again, and the same procedure is repeated thereafter.

<Another Embodiment> (1) The transport means is not transported by a transport belt.
The present invention can be applied to the case of conveyance by a drum (rotary body). (2) The recording medium is not limited to recording paper, but may be a film or the like. In the case of paper, it is preferable to subject the paper material to a surface treatment (forming an acrylic resin layer) so as to easily cause dielectric polarization. Further, a film made of a synthetic resin having a large relative dielectric constant such as an acrylic resin or a polyester resin may be used. (3) The present invention can be applied to a case where a monochrome image is formed instead of a color image as an image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus.

FIG. 2 illustrates the principle of dielectric polarization.

FIG. 3 is a diagram illustrating a configuration of an image forming apparatus according to the related art.

[Explanation of symbols]

 Reference Signs List A transport surface P recording paper 1 ink supply means 2 transport means 3 recording paper supply means 4 charging means 7 static elimination brush 20 transport belt 40 charging roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65H 5/00 B41J 29/00 S

Claims (3)

[Claims] A transport unit configured to transport a recording medium in a state where the recording medium is electrostatically attracted to the transport surface; and supplying ink particles toward the transported recording medium, thereby forming an image on the recording surface of the recording medium. An ink supply unit to be formed; a charging unit provided upstream of a conveyance path of the ink supply unit to charge the conveyance unit and electrostatically attract the recording medium to the conveyance surface; A cleaning unit that is provided downstream of the conveyance path and removes ink attached to the conveyance surface of the conveyance unit after the recording medium is separated from the conveyance unit; and a conveyance path between the cleaning unit and the charging unit. An image forming apparatus provided with the image forming apparatus, wherein the image forming apparatus further includes a charge removing unit configured to remove excess charges on the conveying surface. 2. The image forming apparatus according to claim 1, wherein the charge removing unit is arranged near the charging unit. 3. The method according to claim 2, wherein the static elimination unit contacts the transfer surface,
The image forming apparatus according to claim 1, wherein the image forming apparatus is a static elimination brush adjacent to the image forming apparatus.