JP2000141735A - Direct recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form smaller dots with holes of an qual diameter, prevent toner particles from clogging the holes of a substrate and facilitate cleaning of the holes by enabling the holes to be enlarged in a toner jet type recording apparatus. SOLUTION: A substrate 50 arranged between a recording roller 30 for holding charged toner particles 38 and a back electrode 44 opposite to the recording roller 30 for electrostatically attracting the toner particles 38 has a plurality of holes 56 where the toner particles 38 flying from on the recording roller 30 can pass. Control electrodes 58a and 58b are arranged in the periphery of the holes 56. A direction of an electric field formed by impressing a voltage to the control electrodes 58a and 58b is inclined to a center axis of the hole 56.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an apparatus for recording an image on a recording sheet by causing recording particles to fly and directly attaching to a recording sheet such as paper.

[0002]

2. Description of the Related Art One recording apparatus is disclosed in U.S. Pat. No. 5,477,250. This recording apparatus has a rotating cylindrical toner holding member for holding charged toner particles on the outer peripheral surface, and a back electrode spaced from the toner holding member. The back electrode is electrically connected to a power supply, and forms an electric field for electrostatically attracting charged toner particles on the toner holding member toward the back electrode.
An insulating plate having a plurality of holes through which toner particles can pass is disposed between the toner holding member and the back electrode. The insulating plate has a ring-shaped electrode surrounding the hole.

In the above recording apparatus, when a voltage corresponding to the image data is applied to the ring-shaped electrode, the toner particles at the position facing the ring-shaped electrode on the toner holding member are separated and fly to the corresponding holes. The recording particles that have passed through the holes adhere to the recording sheet to form dots, and an image corresponding to the image data is recorded on the recording sheet by the aggregation of the dots.

[0004]

However, in the above recording apparatus, since the holes in the insulating plate are very small (for example, the inner diameter is 80 to 140 μm), toner particles are easily clogged in the holes. Once the toner particles are clogged in the holes, the toner particles do not fly from the clogged holes, so that a white streak defect occurs in the recorded image.
As a solution to this problem, a method of making the hole diameter less likely to cause toner clogging can be considered. However, as the hole diameter increases, the dot diameter formed accordingly increases, and the recorded image lacks sharpness. There was a problem of becoming something.

[0005]

In order to solve the above-mentioned problems, a direct recording apparatus according to the present invention comprises a holding member for holding charged recording particles, and a recording member which electrostatically opposes the recording particles in opposition to the holding member. Back electrode, which is disposed between the holding member and the back electrode, and a substrate made of an insulating material having a plurality of holes through which the recording particles can pass, and a gap between the substrate and the back electrode. An image holding member that moves in a predetermined direction and has dots formed by the recording particles that have passed through the holes in the substrate and that forms an dot; and an electric field that is arranged around the holes in the substrate and that is formed by applying a predetermined voltage. A control electrode for further strongly electrostatically attracting the recording particles held by the holding member to fly toward the holes, and to control the electric field formed by applying a voltage to the control electrode. Direction Is provided with a said control electrode so as to be inclined with respect to the central axis of Kiana.

In the direct recording apparatus of the present invention, the control electrodes are divided into a plurality of parts, and the plurality of control electrodes are shifted from each other by a predetermined angle with respect to the center axis of the hole, and are provided stepwise in the direction of the center axis of the hole. Alternatively, the control electrode may have a ring shape, and the ring-shaped control electrode may be provided to be inclined with respect to a vertical plane orthogonal to the central axis of the hole.

In the direct recording apparatus of the present invention, the control electrode is obtained by dividing the ring-shaped electrode into a plurality of electrodes, and the conditions for applying a voltage to each of the divided control electrodes may be different. In this case, the timing of turning off the voltage applied to each of the divided control electrodes may be different, or the potential of the voltage applied to each of the divided control electrodes may be different.

Further, in the direct recording apparatus of the present invention, the control electrode is obtained by dividing a ring-shaped electrode into a plurality of electrodes.
Each of the divided control electrodes may have a different size.

[0009]

According to the direct recording apparatus of the present invention, the direction of the electric field formed by the control electrode to which the voltage is applied is inclined with respect to the central axis of the hole in the substrate. The path through which recording particles can pass inside the hole is narrower than when the hole is formed in the central axis direction of the hole. As a result, smaller dots can be formed using holes having the same diameter as in the related art, and a precise and sharp image can be recorded.

On the other hand, by utilizing the fact that the passage of recording particles inside the holes is narrowed by the inclined electric field, the size of the holes used to form dots of the same size as in the prior art is made larger than in the prior art. be able to. Since the holes can be made larger in this way, clogging of recording particles is less likely to occur, and cleaning of the holes becomes easier.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a direct recording apparatus of the present invention indicated by reference numeral 2 as a whole. The recording device 2 has a sheet supply station indicated generally by the reference numeral 4. The sheet supply station 4 has a cassette 6 which is detachable, and stores sheets (image holding members) 8 such as paper in a stacked state. The sheet supply roller 10 is disposed on the cassette 6, rotates while contacting the uppermost sheet 8, and sends out the sheet 8 to the inside of the recording apparatus 2. Near the sheet supply roller 10, a pair of timing rollers 12 are arranged. The sheet 8 sent out from the cassette 6 moves in a predetermined direction along a sheet path 14 indicated by a dashed line, and goes to a recording station (generally indicated by reference numeral 16) for forming an image composed of recording particles on the sheet 8. Supplied. The recording device 2 also includes a fixing station 18 for permanently fixing an image composed of recording particles,
A final stack station 20 for receiving a sheet 8 on which an image of recording particles has been fixed.

Referring to FIG. 2, the recording station 1
Numeral 6 has a recording particle supply section indicated by reference numeral 24 on the sheet path 14. The recording particle supply unit 24 has a container 26, in which an opening 28 facing the sheet passage 14 is formed. A recording roller (holding member) 30 is supported near the opening 28 so as to be rotatable in the direction of arrow 32. The recording roller 30 is made of a conductive material,
It is electrically grounded via a DC power supply 34. The blade 36 is preferably made of a plate made of rubber or stainless steel, and is arranged in contact with the recording roller 30. The recording roller 30 may be directly grounded without passing through the DC power supply 34.

The container 26 contains recording particles, that is, toner particles 38. The toner particles 38
The recording roller 30 is supplied to the outer peripheral surface of the recording roller 30 by a supply roller (not shown) provided therein, and is conveyed as the recording roller 30 rotates. Subsequently, the toner particles 38 held by the recording roller 30 are transported to a contact area between the recording roller 30 and the blade 36, where the toner particles 38 are brought into frictional contact with the blade 36 and charged to a predetermined polarity. In the present embodiment, the toner particles 38 that are negatively charged are used. Therefore, the outer peripheral surface of the recording roller 30 that has passed through the contact area between the recording roller 30 and the blade 36 carries the negatively charged toner particles 38 in a uniform thin layer state. As shown in the figure, the recording roller 30 is supplied with a positive voltage from a power supply 34, thereby electrically adsorbing the negatively charged toner particles 38 to the recording roller 30. When the recording roller 30 is directly grounded, the toner particles 38 are held on the recording roller 30 by a mirror image.

An electrode mechanism, generally designated by the reference numeral 40, is disposed below the recording particle supply section 24 beyond the sheet path 14. The electrode mechanism 40 has a support 42 made of an insulating material and a back electrode 44 made of a conductive material. The back electrode 44 is connected to a power supply 46 for supplying a positive voltage of, for example, +1200 volts, so that the negatively charged toner on the recording roller 30 is
4 so as to be electrostatically attracted. However, the voltage applied from the power supply 46 to the back electrode 44 does not cause the toner particles 38 held on the recording roller 30 to fly by only the electric field formed between the back electrode 44 and the recording roller 30. It is as size.

A substrate, generally designated by the reference numeral 50, is fixed between the recording particle supply section 24 and the electrode mechanism 40 and above the sheet passage 14. The substrate 50 has a thickness of about 100
Preferably, it is made of a flexible printed circuit board 52 made of an insulating material of about 200 μm. As shown in FIGS. 2 and 3,
The portion of the substrate 50 where the recording roller 30 is located in the recording area 54 facing the back electrode 44 has a plurality of holes 56 through which the toner particles 38 flying from above the recording roller 30 can pass. These holes 56 are uniformly arranged at predetermined intervals in a direction perpendicular to the sheet conveying direction (a direction perpendicular to the paper surface of FIGS. 2 and 3).

In the substrate 50, around the hole 56, two divided control electrodes 58a and 58b are provided. As shown in FIG. 4A, each of the control electrodes 58a and 58b has a semi-ring shape, and has a central axis 56a of the hole 56.
Are shifted from each other by about 180 °, and are provided stepwise in the direction of the central axis 56a. That is, one control electrode 58a is arranged near the surface of the substrate 50 on the recording roller 30 side, and the other control electrode 58b is arranged near the surface of the substrate 50 on the back electrode 44 side. A signal output unit 60 is connected to each of the control electrodes 58a and 58b thus arranged.
When a voltage is applied in accordance with the image data, an electric field in a direction inclined with respect to the central axis 56a of the hole 56 is formed in the flying space 53 between the hole 56 and the recording roller 30 and inside the hole 56. It is supposed to be. Hereinafter, such an inclined electric field is referred to as an inclined electric field.

The control electrodes may be divided into three or more, and the angle at which the position of each control electrode is shifted with respect to the central axis 56a of the hole 56 can be arbitrarily changed.

Next, the operation of the recording apparatus 2 will be described. In the recording particle supply section 24, as shown in FIG. 2, the recording roller 30 rotates in the direction of arrow 32. Toner particles 38
Is supplied to the recording roller 30 and is conveyed to a contact area between the blade 36 and the recording roller 30, where a negative electrostatic charge is given to the toner particles 38 by friction with the blade 36. Thus, as shown in FIG. 3, the outer peripheral portion of the recording roller 30 that has passed through the contact area holds the charged toner particles 38 in a uniform thin layer state.

During non-image formation, a negative base voltage of, for example, -100 volts is applied to the control electrodes 58a and 58b. As a result, the negatively charged toner particles 38 on the recording roller 30 are removed from the control electrodes 58a and 58.
b, and is stably held on the recording roller 30 without flying toward the hole 56.

At the time of image formation, a pulse voltage of, for example, +300 volts is applied from the signal output section 60 to the control electrodes 58a and 58b in accordance with the image data. By this voltage application, an inclined electric field is formed inside the flying space 53 and the hole 56. By the action of the inclined electric field, the negatively charged toner particles 38 held on the recording roller 30 are more strongly electrostatically attracted together with the attraction force of the back electrode 44, and peeled off from the recording roller 30 to respond. It flies toward the hole 56.

Here, in the case of a conventional ring-shaped control electrode arranged in parallel with a vertical plane perpendicular to the central axis 56a of the hole 56, the flying space 53 and the hole 56 Therefore, the toner particles 38 flying from the recording roller 30 by the action of the electric field have passed almost the entire circular cross section of the hole 36.
Therefore, when the toner particles 38 that have flown over substantially the entire circular cross section of the hole 56 as a passage path adhere to the sheet 8,
A dot having a size substantially corresponding to the hole 56 was formed.

On the other hand, in the recording apparatus 2, as shown in FIG. 5, since an inclined electric field is formed inside the hole 56, even if the inner diameter of the hole 56 is the same as the conventional one, the toner particles 38 Is substantially narrower. When the toner particles 38 that have flown in the substantially narrow passage 62 adhere to the sheet 8, small dots of high density with clear contours are formed. Therefore, the image formed by the set of dots becomes precise and sharp.

On the other hand, if dots of the same size as in the prior art are formed in the recording apparatus 2, the size of the hole 56 can be made larger than in the prior art. Since the size of the hole 56 can be increased in this manner, the toner particles 38 are less likely to be clogged, and the hole 56 can be easily cleaned with a brush or air.

The sheet 8 on which the image has been recorded as described above is conveyed to the fixing station 18 where the toner particles 38 are heated and permanently fixed to the sheet 8, and finally discharged to the stack station 20.

By the way, in the recording apparatus 2, in order to form an inclined electric field inside the flying space 53 and the hole 56,
The control electrodes 58a and 58b are shifted from each other by about 180 ° with respect to the center axis 56a of the hole 56, and are provided stepwise in the direction of the center axis 56a. As shown in FIG. It may be provided to be inclined with respect to a vertical plane orthogonal to the central axis 56a. This also allows a gradient electric field to be formed.

As shown in FIG. 4 (c), a ring-shaped electrode arranged in parallel with a vertical plane perpendicular to the central axis 56a of the hole 56 is divided into two to form a half-ring-shaped control electrode 58d. , 58e, and these control electrodes 58d,
A gradient electric field may be formed by changing the conditions for applying voltage to 58e. Specifically, each control electrode 58
The timing for turning off the voltage applied to each of the control electrodes 58d and 58e may be different.
May be made to have different potentials,
Alternatively, these control methods may be combined. As a method of changing the timing of turning off the voltage, a voltage of, for example, +300 volts is simultaneously applied to the control electrodes 58d and 58e to turn on the control electrodes 58d and 58e, thereby causing the toner particles 38 to fly from the recording roller 30.
By turning off 8e and returning it to a base voltage of, for example, -100 volts, the control electrode 58 still on
An inclined electric field biased to the d side can be formed. Also,
As a method of making the voltage potential different, the on-potential of the control electrode 58d is set to, for example, +300 volts, and the on-potential of the control electrode 58e is set to, for example, +200 volts, whereby an inclined electric field biased toward the control electrode 58d can be formed. It should be noted that the arrangement of each control electrode as shown in FIG. 4C has an advantage that the production becomes easier as compared with the case where the control electrodes are arranged stepwise.

Further, as shown in FIG.
By dividing a ring-shaped electrode arranged in parallel with a vertical plane perpendicular to the central axis 56 of the control electrode 58f into two,
A gradient electric field can also be formed by forming 58 g and making the control electrodes 58 f and 58 g different in size.

Further, as shown in FIG. 6, half-ring shaped control electrodes 58d and 58e (FIG.
(See (c)), the control electrodes 58h and 58i, which are divided into the second layer, are further provided on the back electrode 44 side.
By shifting the division position of h and 58i from the division position of control electrodes 58d and 58e by a predetermined angle (for example, 90 °), the second inclination that is inclined in a direction different from the inclination electric field formed by control electrodes 58d and 58e. An electric field can be formed inside the hole 56. In this way, the hole 56
Is further narrowed by the second inclined electric field, so that the control electrodes 58d,
The dots formed on the sheet 8 can be made even smaller than in the case where only the inclined electric field is provided by 58e. Therefore, if dots of the same size as in the related art are formed, the hole 56 can be formed larger than in the case where only the control electrodes 58d and 58e are used.

The recording particle supply section 24 in the recording apparatus 2 is not limited to the above-described one, and any type of developing device used in an electrophotographic image forming apparatus may be replaced with the recording particle supply section. Available.

In the recording apparatus 2, an image is recorded by directly adhering the toner particles 38 to the sheet 8. However, the image holding member is, for example, a belt-like or drum-like intermediate transfer body, and is formed on the intermediate transfer body. After an image is once formed by the toner particles 38, the image may be transferred to a sheet such as paper.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a direct recording apparatus.

FIG. 2 is a schematic sectional view of a recording station.

FIG. 3 is a partially enlarged view of a substrate, a recording roller, and a back electrode when a thin layer of toner particles is carried on the recording roller.

4A is a diagram showing an arrangement state of a control electrode with respect to a hole in a substrate, and FIGS. 4B to 4D are diagrams showing a modified example of an arrangement state of a control electrode with respect to a hole in a substrate.

FIG. 5 is a partially enlarged view of a substrate, a recording roller, and a back electrode when toner particles fly from a recording roller and adhere to a sheet through holes in the substrate.

FIG. 6 shows a second control electrode on the back electrode side of the first-layer divided control electrode.
The figure which shows the example which provided the division | segmentation control electrode of the layer.

[Explanation of symbols]

2: Direct recording device, 8: Sheet (image holding member), 30:
Recording roller (holding member), 38: toner particles (recording particles), 44: back electrode, 50: substrate, 56: hole, 58
a, 58b: Control electrodes.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Shibata 2-313 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2C162 AE04 AE31 AE74 AE84 AF70 AH23 CA12 CA19 CA24 2H029 DB04

Claims (7)

[Claims] 1. A holding member that holds charged recording particles, a back electrode that opposes the holding member and electrostatically attracts the recording particles, and is disposed between the holding member and the back electrode. A substrate made of an insulating material having a plurality of holes through which the recording particles can pass; moving in a predetermined direction between the substrate and the back electrode; and the recording particles passing through the holes of the substrate adhere to the substrate and form dots. Is formed, and the recording particles, which are arranged around the hole in the substrate and are held by the holding member by an electric field formed by applying a predetermined voltage, are more strongly electrostatically attracted. A control electrode for flying toward the hole, and the control electrode is provided such that a direction of an electric field formed by applying a voltage to the control electrode is inclined with respect to a center axis of the hole. Features That direct recording device. 2. The control electrode according to claim 1, wherein the plurality of control electrodes are separated from each other by a predetermined angle with respect to a center axis of the hole, and are provided stepwise in a center axis direction of the hole. 2. The direct recording device according to 1. 3. The control electrode has a ring shape,
2. The direct recording apparatus according to claim 1, wherein said ring-shaped control electrode is provided to be inclined with respect to a vertical plane orthogonal to a central axis of said hole. 4. The direct recording apparatus according to claim 1, wherein the control electrode is obtained by dividing a ring-shaped electrode into a plurality of parts, and conditions for applying a voltage to each of the divided control electrodes are different. . 5. The direct recording apparatus according to claim 4, wherein the timing for turning off the voltage applied to each of the divided control electrodes is different. 6. The direct recording apparatus according to claim 4, wherein potentials of voltages applied to the divided control electrodes are different from each other. 7. The direct recording apparatus according to claim 1, wherein the control electrode is obtained by dividing a ring-shaped electrode into a plurality of parts, and each of the divided control electrodes has a different size.