JPH08164629A - Image formation apparatus - Google Patents

Abstract

PURPOSE: To provide an image formation apparatus with the capability to eliminate in advance the static electricity charged in an image recording medium. CONSTITUTION: The cloth W is carried in front of an aperture electrode body 40 annexed at the left end of a process cartridge 31 by means of a cloth carrying mechanism 10 after eliminating the static electricity by a dielectric brush 56, and toner 3 carried by a toner carrying roller 32 flies from the opening by applying driving voltage to the control electrode of the aperture electrode 40, and then it comes into collision against and eventually adhere to the cloth W by an electric field from the rear surface electrode roller 50. Thereafter, it is heat fixed by a fixing mechanism 20.

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 applicable to a copying machine, a printer, a facsimile, etc., by controlling the voltage of control electrodes of a plurality of openings formed in an aperture electrode body, The present invention relates to an image forming apparatus in which toner that has passed through an opening is electrostatically attached to an image recording medium for recording, and in particular, it is possible to improve the toner flying property by recording the image after removing the static electricity charged in the image recording medium. Regarding what you did.

[0002]

2. Description of the Related Art Conventionally, an insulating sheet is formed with a plurality of openings arranged in a line in a direction orthogonal to the conveying direction of an image recording medium and an electrode array consisting of a plurality of control electrodes located near these openings. An aperture electrode body, a toner supply mechanism that supplies toner to the electrode array of the aperture electrode body, and a back electrode that closely faces the electrode array of the aperture electrode body with a conveyance gap of the image recording medium. A control unit that individually controls the drive voltage applied to the plurality of control electrodes of the electrode array based on the image signal is provided, and the control unit applies the voltage to each control electrode via the electrode drive circuit based on the image signal. The drive voltage is controlled so that the toner on the surface of the toner transport roller passes through the opening through the electric field between the control electrode and the toner transport roller and the electric field between the control electrode and the back electrode. An image forming apparatus configured with an electrostatic recording method to record the image recording medium (recording paper) by static electricity, have been proposed (e.g., JP-2─
297570 and JP-A-6-155798).

In this type of image forming apparatus, a recording paper of a predetermined size such as A4 size is generally used as an image recording medium, and the plurality of openings are usually formed.
A minute opening having a diameter of about 65 to 100 μm,
The toner supply mechanism is configured such that the peripheral surface of the toner transfer roller is negatively charged and toner is adhered to the toner, and then the toner is supplied. About +1000 V is applied to the back electrode, and the control electrode is responsive to the presence or absence of pixel formation. + 30B or -30V
Is configured to be applied.

[0004]

As described above, in the image forming apparatus described in JP-A-2-297570 and JP-A-6-155798, the recording paper of a predetermined size such as A4 size is used. It is used as an image recording medium to form an image by adhering a toner image corresponding to an image signal to this recording sheet by an electrostatic recording method. For example, a colorfully dyed cloth or an overhead sheet other than the recording sheet is used. Transparent synthetic resin OH used for projectors
It is also conceivable to record an image on various image recording media such as a P sheet.

By the way, in particular, these OHP sheets,
When using fabrics made of chemical fibers such as nylon, cupra, jersey, etc., fabrics made of natural fibers such as wool, tweed, art-coated paper or high-quality paper as the image recording medium, these image recording media may be Since a large amount of static electricity is likely to be charged, when the toner is charged on the negative electrode, if the static electricity on the negative electrode is charged on the image recording medium, for example, the toner and the image recording medium have the same polarity. Therefore, the toner flying through the opening of the aperture electrode body is attracted by the large electrostatic force of the back electrode while repelling the image recording medium, and thus the image is diffused to the back electrode. There is a problem that the image quality is deteriorated because the image adheres to the recording medium and the image is distorted.

On the other hand, when the image recording medium is charged with, for example, the static electricity of the positive electrode, the toner and the image recording medium have different polarities. The flying property of the toner is not deteriorated by being attracted to the recording medium, but when the image recording medium comes into contact with the control electrode, the static electricity of the image recording medium and the negative drive voltage applied to the control electrode are short-circuited. Then, there is a problem that the electronic parts may be damaged.

An object of the present invention is to remove excess static electricity charged on the image recording medium in advance, thereby improving the straightness of the toner when flying to the back electrode and improving the image quality. An object of the present invention is to provide an image forming apparatus capable of preventing damage.

[0008]

According to another aspect of the present invention, there is provided an image forming apparatus, wherein a plurality of openings are provided in an insulating sheet in a direction orthogonal to a conveying direction of an image recording medium, and a plurality of openings are provided near the openings. Aperture electrode body formed with an electrode array consisting of control electrodes, a toner supply mechanism for supplying toner to the electrode array of the aperture electrode body, and a gap for conveying the image recording medium with respect to the electrode array of the aperture electrode body. In an image forming apparatus provided with back electrodes that face each other in close proximity and an electrode control unit that individually controls a drive voltage applied to a plurality of control electrodes of an electrode array based on an image signal, an image is formed via a conveyance gap. A charge removing unit that is provided so as to face the transport path on the upstream side of the electrode array in the transport direction of the transport path that transports the recording medium in a predetermined transport direction. Those having a charge eliminating means for removing prior to static electricity of the toner adhesion.

Here, the image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect of the present invention, wherein the charge eliminating means is composed of a grounded conductive brush. According to a third aspect of the present invention, in the first aspect of the invention, the discharging unit is composed of a grounded conductive roller member.

[0010]

In the image forming apparatus according to the present invention, the aperture electrode body is formed by forming a plurality of openings in the insulating sheet and an electrode array consisting of a plurality of control electrodes located in the vicinity of these openings. The back electrode closely faces the electrode array with a conveyance gap of the image recording medium therebetween, toner is supplied to the electrode array by the toner supply mechanism, and the electrode control means causes the plurality of electrodes of the electrode array to be supplied based on the image signal. By individually controlling the drive voltage applied to the control electrode, the toner passing through the opening is caused to fly through the electric field between the control electrode and the toner supply mechanism and the electric field between the control electrode and the back electrode, and the image is formed. An image is recorded on the recording medium.

Here, among the transport paths for transporting the image recording medium in the predetermined transport direction through the transport gap, the static elimination means provided so as to face the transport path upstream of the electrode array in the transport direction. , The static electricity charged on the image recording medium,
Since the toner is removed before the toner is attached, the electric field generated between the control electrode and the back electrode and the toner are not electrostatically affected by the image recording medium. Electrostatic force due to the electric field of the electrodes improves the straightness when flying to the back electrode, so that the image quality can be improved, and even when the image recording medium comes into contact with the control electrode, no short circuit occurs, and therefore the electrode control means is provided. The electronic components of will not be damaged.

In the image forming apparatus according to the second aspect of the present invention, the same operation as that of the first aspect is achieved, but since the discharging means is composed of a grounded conductive brush, image recording is performed by using a simple brush. The static electricity charged on the medium can be reliably removed.

In the image forming apparatus according to the third aspect of the present invention, the same operation as that of the first aspect is achieved, but since the discharging unit is composed of a grounded conductive roller member, the image recording medium is particularly thick. Even with a fluffy cloth, the static electricity charged on the cloth can be reliably removed without any trouble.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the image forming apparatus 1 is an electrostatic image recording apparatus applicable to a copying machine, a printer, a facsimile, a plotter, and the like.
Is configured to record an image such as a cutting mark on various kinds of cloth W, and a cloth conveying mechanism 10 for conveying the cloth W (image recording medium) to a main body frame (not shown), The fixing mechanism 20, a predetermined amount of toner 3, a toner supply mechanism 30 having a process cartridge 31, an aperture electrode body 40 attached to the left end of the process cartridge 31, an aperture electrode body 40, and a cloth conveyance gap (for example, The back electrode roller 50 is provided at a distance of about 20 mm.

The cloth transporting mechanism 10 has a flat cloth W.
A wide conveyance belt 11 composed of an endless belt body that conveys while supporting a sheet, a plurality of conveyance rollers 14 and 15 that conveys and drives the conveyance belt 11, and a roller driving mechanism that drives the cloth conveyance mechanism 10. (Not shown) and the like. Here, the transport belt 11 detachably supports and fixes the front end portion of the cloth W used for image formation, and the rear end portion of the cloth W is detachably supported and fixed thereto. The rear end fitting 13 is fixed. The fixing mechanism 20 includes a fixing roller 16 having a halogen lamp built therein and a pressing roller 17, and presses the toner 3 recorded on the surface of the cloth W (the recording surface on the right side in FIG. 1) while heating the cloth W. Is to be fixed in.

Next, the toner supply mechanism 30 will be described. A detachable process cartridge 31 is provided in a body frame (not shown). The process cartridge 31 has a width wider than the maximum width of the cloth W in a direction orthogonal to the cloth conveying direction (from the lower side to the upper side), and the toner 3 having an electrically insulating property is stored in the process cartridge 31. ing. Further, inside the process cartridge 31, there are a toner transport roller 32, a toner supply roller 33 that supplies the toner 3 to the toner transport roller 32, and a toner supply plate 34 that supplies the toner 3 to the toner supply roller 33. The rollers 32, 33 and the toner supply plate 34 are horizontally arranged in the left-right direction, and are rotatably supported.

Here, the toner supply roller 33 is made of a silicone foam, and the toner supply roller 33 transfers the toner 3 toward the toner conveying roller 32 and is in frictional contact with the toner 3. The toner 3 is charged on the negative electrode. The toner carrying roller 32 is a roller body 32a made of a synthetic resin foam made of an insulating material.
A toner sleeve 32b made of nickel is externally fitted to the outer circumference of the toner carrier roller 32, and the toner 3 attached to the surface of the toner carrier roller 32 by electrostatic force is carried in the direction of arrow A. The toner supply roller 33 and the toner transport roller 32 are rotationally driven in the arrow B direction and the arrow A direction by a roller driving mechanism (not shown). Incidentally, a synthetic resin insulating coating or semi-conductive coating may be formed on the entire circumferential surface of the toner transport roller 32.

Inside the process cartridge 31, a toner layer regulating blade 35 made of an insulating material having a thin plate-like elasticity is attached, and its curved portion is in contact with the toner conveying roller 32 in a pressing manner to convey toner. Roller 3
The layer thickness of the toner 3 layered on the surface of 2 is regulated to a predetermined thickness (about 40 to 50 μm) by the toner layer regulation blade 35.

At the left end of the process cartridge 31,
An aperture electrode body 40 that is inclined approximately in a roof shape is attached so as to cover the opening portion at the left end of the process cartridge 31 and to contact the left end portion of the toner transport roller 32 from the left side via the layered toner 3. . The aperture electrode body 40 will be described. As shown in FIGS. 2 and 3, the aperture electrode body 40 includes an insulating sheet 41 made of synthetic resin (for example, polyimide) and having a thickness of about 25 μm.
A large number of minute openings 42, and an electrode array 44 composed of a large number of annular control electrodes 43 respectively formed on the outer periphery of the large number of openings 42 on the surface (the surface on the left side in FIG. 2) of the insulating sheet 41. The control electrodes 43 are composed of a large number of conducting wires 45 extending in a predetermined direction.

A large number of openings 42 are formed in a row in the horizontal direction orthogonal to the conveyance direction of the cloth W at predetermined minute intervals at a position substantially in the center of the insulating sheet 41 in the vertical direction. On the surface of the insulating sheet 41, an annular control electrode 43 made of a copper film and surrounding the outer circumference of each opening 42 and a conductive wire 45 made of a copper film integrally extending from the control electrode 43 are formed. . The diameter of the opening 42 is, for example, about 65 μm.
The pitch between the openings 42 is about 127 μm, and a large number of openings 42 are formed according to the size of the fabric W.

On the other hand, as shown in FIG. 1, the back electrode roller 50 (this corresponds to the back electrode) is provided on the immediate left side of the aperture electrode body 40 with a feeding gap for feeding the cloth W therebetween.
The rear electrode roller 50 is provided with a support shaft 5
It is rotatably supported by the main body frame via 0a, and is rotationally driven in the direction of arrow C in synchronization with the conveyance of the conveyance belt 11 by a roller driving mechanism (not shown). The cloth W is conveyed in the conveying direction while being in contact with the front end portion of the back electrode roller 50, and the surface of the cloth W is controlled by the control electrode 4 during conveyance.
The toner transport roller 3 according to the drive voltage applied to the roller 3.
The toner 3 that has flown from the surface of 2 and has passed through the opening 42 is attached. That is, the transport path for transporting the fabric W in the transport direction via the transport gap between the aperture electrode body 40 and the back electrode roller 50 corresponds to the transport trajectory of the transport belt 11 that is orbitally driven.

Next, the static elimination mechanism 55 provided so as to face the transport path on the upstream side of the electrode array 44 in the transport direction will be described with reference to FIG. Immediately upstream of the process cartridge 31 in the transport direction, that is, immediately below the process cartridge 31, a conductive static elimination brush 56 having a large number of metallic wires such as fine stainless fibers planted at its tip is provided as a main body. The static elimination brush 56 is attached to the frame and is grounded. Then, the tip end of the static elimination brush 56 slightly contacts the conveyed fabric W, whereby the static electricity charged on the fabric W is surely removed, and then the neutralized fabric W is discharged.
The toner 3 that has passed through the opening 42 is attached. Here, the static elimination brush 56 is not limited to the stainless fiber, and a fiber in which copper is mixed with carbon fiber or acrylic, or a fiber in which carbon is mixed with acrylic may be used.

Next, the control system of the image forming apparatus 1 will be briefly described with reference to FIG. 3. A high voltage of about +1 KV is constantly applied to the back electrode roller 50 by the power supply circuit 61, and a negative voltage is applied. The charged toner 3 is attracted to the back electrode roller 50 by a large electrostatic force. On the other hand, a control unit 60 that receives an image signal from the outside, a power supply circuit 62, and an electrode drive circuit 63 are provided, and the control unit 60 causes a large number of control electrodes to be transmitted via the electrode drive circuit 63 based on the image signal. It is configured to control the drive voltage applied to 43. Also,
The toner transport roller 32 is always grounded.

That is, a large number of conductive wires 4 of the aperture electrode body 40.
5 is connected to an electrode drive circuit 63 via a control line 64 composed of a large number of signal lines.
Two kinds of drive voltages of + 30V and -30V are supplied from the power supply circuit 62. The control unit 60 sends a control signal corresponding to the image signal for the plurality of control electrodes 43 to the electrode drive circuit 6
3 simultaneously, and the electrode drive circuit 63 applies a drive voltage of +30 V to each control electrode 43 for recording a pixel.
Each control electrode 4 which outputs through 4 and does not record pixels
A drive voltage of −30 V is output to the control line 3 via the control line 64.

Next, the image forming operation of the image forming apparatus 1 described above and the operation of the image forming apparatus 1 will be described. First, at a predetermined cloth attachment position, the cloth W to be used for image formation is fixed to the conveyance belt 11 by the front end fitting 12 and the rear end fitting 13 at the front end and the rear end of the cloth W. Then, the conveyor belt 11 is driven to rotate by the plurality of conveyor rollers 14 and 15, and as shown in FIG. 1, the cloth W conveyed by the conveyor belt 11 sequentially contacts the static elimination brush 56 from its tip. By doing so, the charged static electricity is transported to the electrode array 44 while being reliably removed by the static elimination brush 56.

Then, as shown in FIG. 3, the toner 3 charged on the negative electrode is transported to the electrode array 44 while being attached to the peripheral surface of the toner transport roller 32, and +30 V is applied to the control electrode 43. Then, the toner 3 receives an electrostatic force from the electric field traveling from the control electrode 43 to the toner transport roller 32, passes through the opening 42, and flies toward the control electrode 43, and further from the back electrode roller 50 to the control electrode 4.
3 receives the electrostatic force from the strong electric field toward 3, and flies linearly toward the back electrode roller 50, collides with the cloth W and adheres thereto. However, when −30 V is applied to the control electrode 43, the toner 3 is transferred from the toner transport roller 32 to the control electrode 4
3 receives an electrostatic force from the electric field directed toward 3 and does not pass through the opening 42. Then, the toner image on the cloth W is then heat-fixed on the cloth W by the fixing mechanism 20.

As described above, since the static elimination brush 56 is provided so as to face the transport path on the upstream side in the transport direction of the electrode array 44 of the aperture electrode body 40, the static electricity charged on the cloth W is attached to the toner 3. Is removed prior to
The electric field generated between the control electrode 43 and the back electrode roller 50 and the toner 3 are not affected by the cloth W at all, so that the toner 3 passing through the opening 42 flies straight to the back electrode roller 50. As a result, the image quality can be improved. Further, the static electricity charged on the cloth W can be surely removed by using the simple static elimination brush 56. In addition, since the static electricity of the cloth W used for image formation is surely removed and conveyed to the electrode array 44, even if the cloth W comes into contact with the control electrode 43, a short circuit does not occur. Therefore, an electronic component of the electrode drive circuit 63 is provided. Will not be damaged.

By the way, as shown in FIG. 4, in the image forming apparatus 1A, a metal roller member 57, which is wider than the cloth width in the roller axial direction, is rotated in place of the static elimination brush 56 on the main body frame. The static elimination mechanism 55A may be configured so as to be pivotally supported and grounded as much as possible, and to be disposed in contact with the conveyed fabric W. In this case, even if the fabric W transported by the transport belt 11A for image formation has a particularly thick fluff, the static electricity charged on the fabric can be reliably removed without any trouble. Further, the curved portion of the grounded static eliminator, which is wider than the cloth width and has a substantially curved shape in a side view, may be disposed in contact with the cloth W.

When the polarity of the static electricity charged on the cloth W is known, the static elimination mechanism is constructed so as to discharge the static electricity by discharging a high voltage, or the surface of the cloth W opposite to the toner adhering surface. Within the scope of the technical idea of the present invention, such as by separately providing a static eliminating mechanism for removing static electricity on the cloth surface on the side,
Various modifications may be made based on existing technology or technology obvious to those skilled in the art. Incidentally, various image recording media such as recording paper, OHP sheets for overhead projectors, and cloths are configured to be conveyed not only in the vertical direction but also in the horizontal direction, and the toner 3 is attached to the image recording medium by the aperture electrode body. Of course, the present invention can be applied to various image forming apparatuses configured to be controlled by 40.

[0030]

According to the image forming apparatus of the first aspect of the present invention, the static eliminating means is provided so as to face the transport path on the upstream side of the electrode array in the transport direction. Since the toner is removed prior to the adhesion, the electric field generated between the control electrode and the back electrode is not affected by the image recording medium at all, so that the straightness when the toner passing through the opening flies to the back electrode is reduced. As a result, the image quality can be improved, and even if the image recording medium comes into contact with the control electrode, the electronic component of the electrode control means is not damaged because the short circuit does not occur.

According to the image forming apparatus of the second aspect, the same effect as that of the first aspect can be obtained. However, since the discharging unit is composed of a grounded conductive brush, an image is formed by using a simple brush. The static electricity charged on the recording medium can be reliably removed. According to the image forming apparatus of the third aspect, the same effect as that of the first aspect is obtained, but since the discharging unit is composed of a grounded conductive roller member, the image recording medium has a particularly thick fluff. Even with cloth, the static electricity charged on the cloth can be reliably removed without any trouble.

[Brief description of drawings]

FIG. 1 is a partial vertical schematic side view of an image forming apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a partial perspective view of the aperture electrode body of the image forming apparatus as viewed from the control electrode side.

FIG. 3 is an enlarged cross-sectional view of a main part of the image forming apparatus in FIG.

FIG. 4 is a view corresponding to FIG. 1 in which a roller member is provided according to a modification.

[Explanation of symbols]

 1 Image Forming Apparatus 3 Toner 11 Transport Belt 30 Toner Supply Mechanism 32 Toner Transport Roller 33 Toner Supply Roller 40 Aperture Electrode Body 42 Opening 43 Control Electrode 44 Electrode Array 50 Back Electrode Roller 55 Static Elimination Mechanism 56 Static Elimination Brush 57 Roller Member 60 Control unit 63 electrode drive circuit W cloth

Claims (3)

[Claims] 1. An aperture electrode in which a plurality of openings arranged in a line in a direction orthogonal to a conveyance direction of an image recording medium and an electrode array formed of a plurality of control electrodes near the openings are formed on an insulating sheet. Body, a toner supply mechanism that supplies toner to the electrode array of the aperture electrode body, a back electrode that closely opposes the electrode array of the aperture electrode body across the conveyance gap of the image recording medium, and based on the image signal. And an electrode control unit for individually controlling drive voltages applied to a plurality of control electrodes of an electrode array, wherein a transport path for transporting an image recording medium in a predetermined transport direction via the transport gap. Of the above, the static elimination means is provided so as to face the transport path on the upstream side of the electrode array in the transport direction, and removes static electricity charged on the image recording medium prior to toner adhesion. An image forming apparatus comprising the charge-eliminating unit that. 2. The image forming apparatus according to claim 1, wherein the charge removing unit is formed of a grounded conductive brush. 3. The image forming apparatus according to claim 1, wherein the charge removing unit is formed of a grounded conductive roller member.