JP2000168092A - Image forming method and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic continuance ink-jet type method for forming images and an apparatus therefor whereby more nozzles can be easily arranged with a high-density in comparison with the case using a flat deflecting electrode and a shift in impact position of charged ink drops from nozzles can be made small. SOLUTION: The image-forming apparatus has an ink drop-discharging means for discharging charged ink drops 52 from a nozzle hole 12 of an ink container 10, and an ink drop flight controlling means for selectively deflecting charged ink drops 52 in accordance with image information, and selectively adheres charged ink drops 52 onto a paper 53 thereby forming images on the paper 53. In the apparatus, the ink drop flight-controlling means is constituted by using an ink drop flight-controlling member 30 having a plurality of through holes 33 surrounded by image electrodes 31 and a control voltage-impressing means for impressing a control voltage to the image electrodes 31 so as to selectively deflect the charged ink drops 52 according to image information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile and the like, and an image forming method executable by the apparatus. The present invention relates to an ink jet type image forming method and an apparatus for forming an image on an image forming object by selectively deflecting the charged ink droplet on the image forming object by deflecting the charged ink droplet.

[0002]

2. Description of the Related Art Conventionally, this type of ink jet type image forming apparatus includes an on-demand ink jet type image forming apparatus which controls whether or not ink droplets are ejected from nozzles according to image information, and an ink jet type image forming apparatus which includes all nozzles. 2. Description of the Related Art A continuous ink jet type image forming apparatus is known which continuously ejects ink droplets and selectively deflects flying ink droplets from the nozzles according to image information. In the former on-demand ink jet type image forming apparatus, it is necessary to form small partitioned and independent ink storage chambers in a portion adjacent to each nozzle hole of an ink container constituting a nozzle head, and a multi-nozzle nozzle head is required. Was difficult to produce in high yield. On the other hand, the latter continuous ink jet type image forming apparatus has an advantage in that it is not necessary to partition the inside of the ink container into a small size, and the manufacture of the nozzle head is relatively easy.

In the continuous ink jet type image forming apparatus, a charged ink droplet ejected from a nozzle of an ink container is selectively deflected by an electrostatic force to select the charged ink droplet on an image forming object. Continuous ink jet (hereinafter, referred to as “electrostatic IJ”) for forming an image on the image forming object by being adhered thereto
2. Description of the Related Art A type of image forming apparatus is known. FIG. 91 is a schematic configuration diagram showing an example of the electrostatic IJ type image forming apparatus.
In this apparatus, an ink column 102 discharged from a nozzle 101 is cut in a ring-shaped charging electrode 103 to which a predetermined voltage (+200 V in this example) is applied, and an ink droplet 104 is formed.
Is formed, the positive charge that has been electrostatically induced (charge injected) remains in the low-resistance ink column 102. As a result, the ink droplet 104 is positively charged. This charged ink droplet 104
Is a deflecting electrode 1 which goes straight and is composed of a pair of conductive parallel plates.
Enter between 05a and b. In the figure, +1800 V is applied to the upper deflection electrode 105a, and the lower deflection electrode 105b is grounded.
04 receives a downward electrostatic force, its flight path is deflected downward, and enters the garter 106 as an ink droplet receiving member and is collected. When the nozzle 101 is grounded, no electric charge is injected into the ink column 102, so that an uncharged ink droplet 104 is formed, and the nozzle 101 moves straight without receiving a downward electrostatic force between the deflection electrodes 105a and 105b.
7 lands on the paper (image forming object). Here, the voltage applied to the nozzle 101 based on the image data is +20.
By switching between 0V and 0V, an image can be formed on the paper. Further, as shown in FIG. 92, the uncharged ink droplet 104a that goes straight is collected by the garter 106, and the charged ink droplet 1 deflected by the deflection electrodes 105a and 105b.
There is also known an electrostatic IJ-type image forming apparatus configured to form an image on the paper 108 by using 04b. Typical dimensions of each member and typical characteristics of ink droplets in these electrostatic IJ-type image forming apparatuses are as follows. For example, in the apparatus shown in FIG. 91, the length of the charging electrode 103 in the ink droplet flying direction is about 10 mm, the length of the deflecting electrodes 105a and 105b is about 30 mm, the distance between the nozzle 101 and the charging electrode 103, and the distance between the charging electrode 103 and the deflecting electrode. The distance between the electrodes 1051 and 105b is 1 mm or less, the diameter of the charging electrode 103 is 2 mm or less, and the distance between the upper and lower deflection electrodes 105a and 105b is several mm. The flying speed of the ink droplet 104 is about 20 m / sec, and the diameter of the ink droplet 104 varies depending on the resolution of an image to be formed.
μm, and the charge amount (Q / M) of the ink droplet 104 is 3 μC / g.

However, when applying the configuration shown in FIG. 91 or 92 to an apparatus having a plurality of nozzles, it is necessary to apply different voltages to the nozzles and the charging electrodes according to image data. It is difficult to make the nozzle narrow, and this is disadvantageous in that a high-density multi-nozzle is achieved. Also, in the configuration of FIG. 91 or FIG. 92, a constant voltage is applied to the nozzle and the charging electrode to uniformly charge the ink droplet ejected from the nozzle, and the ink droplet is applied to the deflecting electrodes 105a and 105b in accordance with the image information. Although it is conceivable to adopt a configuration for selectively deflecting, it is necessary to apply different voltages to the deflection electrodes 105a and 105b in accordance with image information. This is disadvantageous in that high-density multi-nozzles are achieved.

Therefore, an electrostatic IJ type image forming apparatus as shown in FIG. 93 has been proposed as an apparatus which can be easily provided with more nozzles than the configuration shown in FIG. 91 or FIG.
1988 `` THE FOURTH INTERNATIONAL CONGRESS ON ADV
ANCES IN NON-IMPACT PRINTING TECHNOLOGIES '', `` DROP CHARGING AND DEFLECTION USING A PLA '' presented by JAMES A. KATEERBERG of EASTMAN KODAK
NAR CHARGE PLATE "). In the apparatus shown in FIG. 93, the ground electrode of the pair of deflection electrodes is eliminated, and the deflection electrode also serves as a charging electrode. As a result, it is possible to make the interval between nozzles smaller than in the conventional method. When a signal voltage is applied to the deflection electrode 109 also serving as a charging electrode, the ink column 1
A charge of the opposite polarity is electrostatically induced (charge injection) at the tip of 02, and the torn ink droplet 104 is charged to the opposite polarity. The charged ink droplet having the opposite polarity is drawn by the deflection electrode 109 and deflected, and is caught by the catcher 110. On the other hand, the uncharged ink goes straight to form an image on the paper 108. FIG. 94
FIG. 94 is an explanatory view for explaining the principle of charging and deflection in the apparatus of FIG. 93. A negative voltage is applied to the charging electrode (deflecting electrode) 109, and the nozzle (orifice plate) 111 a on the lower surface of the ink container 110 and the catcher 110
Is grounded, lines of electric force are formed as shown in FIG. 94, and a positive charge is induced at the tip of the ink column 102. An electrostatic force toward the charging electrode 109 acts on the ink droplet 104 formed with the positive charge, and the ink droplet 104 is deflected in that direction. The length of the charging electrode 109 in the vertical direction in the drawing is 0.635 mm, and the ink column 102 is cut at a distance of 0.127 mm from the upper end to form an ink droplet 104. As a result, the ink droplet is deflected by 0.23 mm below the charging electrode 109 by 2.8 mm.

Further, an electrostatic IJ type image forming apparatus as shown in FIG. 95 has also been proposed (Reference 2: “THE” of 1989).
FIFTH INTERNATIONAL CONGRESS ON ADVANCES IN NON-IM
PACTPRINTING TECHNOLOGIES '', `` TRAVELING WAVE D '' announced by Naoki Morita of FUJI XEROX
ROP GENERATOR FOR MULTI-NOZZLE CONTINUOUS INK JE
T "). The apparatus shown in FIG. 95 is basically a general electrostatic IJ type image forming apparatus having only a multi-nozzle.
In order to reduce the number of plate-shaped deflection electrodes to half, the deflection voltage is changed to + and-every other electrode as shown in the figure. As a result, the charged ink droplets 104 to be collected are alternately deflected right and left. Thereby, only one garter 106 is required. The drop sensor 112 behind the paper 108 would measure the point of impact for each nozzle and feed the results back to the charging controller.

An electrostatic IJ type image forming apparatus as shown in FIG. 96 has also been proposed (Reference 3: IS &T's NIP1).
2: International Conference on Digital Printing Te
chnologies-'87 Proceedings, Shogo Ma of Hitachi Ltd.
"Flight Stability of Dro" announced by tsumoto
plets in an Electrostatic Ink-Jet Printer ”). In the apparatus shown in FIG. 96, each ink droplet 104 ejected from the nozzle 101 travels straight without being charged by the charging electrode 103 and is collected by hitting the garter 106, or is charged by the charging electrode 103 and deflected by paper. 108 was printed. At this time, by changing the voltage applied to the charging electrode 103 (the deflection voltage applied to the deflection electrodes 105a and 105b is fixed), the printing position can be changed by changing the charge amount of the ink droplet 104. According to the above document describing the configuration of the apparatus, the deflection electrodes 105a, 105
The length of b is about 40 mm, the distance between the electrodes is about 4 mm, and the deflection voltage is about 4 kV.

[0008]

However, FIG.
96 has the following problems. (1) Crosstalk occurs and the landing position shifts. For example, in FIG. 93, the foremost ink droplet 104 is charged and collected by the catcher 110, and the second ink droplet from the foreground is straightened without being charged and applied to the paper 108. Is induced, and the electric field formed between the first and second charging electrodes (deflection electrodes) 109 causes
It is deflected in the direction of the second charging electrode, and the landing point on the paper 108 is out of order. (2) To reduce crosstalk, the charging electrode 10
9 must be widened, and it is difficult to increase the density.
(The thickness of the charging electrode (length in the vertical direction)
However, there is no description about the width of the depth and the distance between adjacent electrodes. Judging from the fact that the thickness of the charging electrode 109 is 0.6 mm and FIG. 93, it is considered that the pitch of the charging electrode 109 is substantially the same as the thickness. (3) Since a high voltage cannot be applied to reduce crosstalk, the deflection distance is short and unstable. In a typical electrostatic IJ-type device, a deflection electrode is provided separately from the charging electrode, and a high voltage (several kV) is applied to the deflection electrode. Therefore, the deflection distance is several mm, and the paper is sufficiently reliable. And the ink drops to be collected can be separated.

Particularly, in the apparatus shown in FIG.
If the dimensions of 05a and 105b are large and the voltage is high, it is very difficult to form a line head by closely arranging them.
In a commercialized line head electrostatic IJ type image forming apparatus (DIJIT printer manufactured by Mead: trade name), the nozzle pitch was 0.5 mm. Such long deflection electrodes 105a and 105b and a high deflection voltage are required because the speed of the ink droplet is very high (for example, in the above-mentioned reference 3 which describes the apparatus of FIG. 96, it becomes 20.2 m / sec). It is thought that it is because.

The apparatus shown in FIG. 95 has the following problems. (1) Since there is a limit to reducing the thickness of the deflection electrode,
It is difficult to increase the density of the nozzle. In order to accurately maintain the position of the deflecting electrodes opposed to each other across the flight path of the ink droplet, the thickness is at least 0.1 m from the viewpoint of mechanical strength.
m is required. In addition, the ink droplets are selectively deflected to be divided into ink droplets for image formation and ink droplets to be collected. The deflection distance needs to be at least 0.1 mm or more. Considering these, the minimum pitch between nozzles is 0.5m
m, ie, 50 dpi, is expected to be the maximum density. This is the case where the nozzles are arranged in a straight line. However, when the nozzles are arranged in a zigzag pattern, thin deflection electrodes having a length of several mm must be arranged in a staggered arrangement, and both production and holding are difficult. (2) The speed cannot be increased because there are too many dots to be formed by ink droplets ejected from one nozzle hole.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a high-density multi-nozzle nozzle as compared with a case where a conventional flat deflection electrode is used as ink droplet flight control means. And a continuous ink jet type image forming method capable of reducing crosstalk in a control electric field for controlling charged ink droplets ejected from each nozzle and reducing displacement of an impact position of the ink droplet, and a method thereof. It is to provide a device.

[0012]

In order to achieve the above object, the invention of claim 1 is to selectively deflect a charged ink droplet flying in one direction in accordance with image information, so that the charged ink droplet is charged. In an image forming method for forming an image on an image forming object by selectively adhering ink droplets on the image forming object, a through hole surrounded by an image electrode to which a control voltage corresponding to image information is applied , The charged ink droplets are made to fly toward, and the charged ink droplets passing through the through holes are selectively deflected. In this image forming method, a control electric field for controlling the deflection of ink droplets is provided inside a through-hole that is not easily affected by static electricity from the surroundings by an image electrode to which a control voltage is applied according to image information. It is formed. By this control electric field, the charged ink droplet which is going to pass through the through hole is selectively deflected.
An image is formed by ink droplets of the charged ink droplets flying toward the image forming object.

According to a second aspect of the present invention, in the image forming method of the first aspect, the charged ink droplets flying in a direction different from the direction toward the image forming object are collected. In this image forming method, by collecting charged ink droplets flying in a direction different from the direction toward the image forming object, the inside of the apparatus is not contaminated by the ink droplets, and the ink droplets are re-used. Make it available.

According to a third aspect of the present invention, in the image forming method of the first aspect, the charged ink droplet flying toward the through hole is decelerated. In this image forming method, the charged ink droplet flying toward the through hole is decelerated so that the ink droplet can be deflected with a smaller control voltage.

According to a fourth aspect of the present invention, in the image forming method of the first aspect, based on the image information, the charged ink droplet passing through the control electric field forming region by the image electrode and flying toward the image forming object is formed. Deflection of the charged ink droplets on the image forming object. In this image forming method, based on image information, a charged ink droplet passing through a control electric field forming region by the image electrode and flying toward an image forming object is deflected, and the ink droplet on the image forming object is deflected. By changing the attachment position, a plurality of dots of an image can be formed by ink droplets passing through one control electric field forming region.

According to a fifth aspect of the present invention, there is provided an ink droplet ejecting means for ejecting a charged ink droplet from a nozzle hole of an ink container, and an ink droplet flying control means for selectively deflecting the charged ink droplet in accordance with image information. An image forming apparatus for forming an image on the image forming object by selectively adhering the charged ink droplets on the image forming object, wherein the ink droplet flying control means includes a penetrating member surrounded by an image electrode. An ink droplet flight control member having a plurality of holes formed therein, and control voltage applying means for applying a control voltage for selectively deflecting the charged ink droplets according to image information to the image electrode. It is characterized by the following. In this image forming apparatus, a control voltage is applied to each image electrode of the ink droplet flying control member according to image information by a control voltage application unit. Each image electrode to which the control voltage is applied controls the deflection of ink droplets inside each through hole surrounded by the image electrode and hardly affected by static electricity from the surroundings. An electric field is formed. By this control electric field, the charged ink droplets passing through each through hole are selectively deflected. An image is formed by ink droplets of the charged ink droplets flying toward the image forming object.

According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, ink drop collecting means for collecting charged ink drops flying in a direction different from the direction toward the image forming object is provided. It is assumed that. In this image forming apparatus, the inside of the apparatus is prevented from being contaminated by the ink droplets by collecting charged ink droplets flying in a direction different from the direction toward the image forming object by the ink droplet collecting means, and Make ink drops reusable.

According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, the ink droplet collecting means is provided in a direction different from a direction toward the image forming object, with respect to a collecting container for storing the collected ink droplets. An ink droplet collecting member is provided for receiving the flying charged ink droplets and guiding the charged ink droplets to the collection container. In this image forming apparatus, the charged ink droplet flying in a direction different from the direction toward the image forming object is received by the ink droplet collecting member, guided to the collecting container, and the ink droplet is collected in the collecting container.

According to an eighth aspect of the present invention, in the image forming apparatus according to the sixth aspect, the ink droplet collecting means is provided with a collecting port through which charged ink droplets flying in a direction different from the direction toward the image forming object directly enter. The present invention is characterized in that it is configured using a collection container having the same. In this image forming apparatus,
Charged ink droplets flying in a direction different from the direction toward the image forming object are directly inserted into the collection port of the collection container and collected in the collection container.

According to a ninth aspect of the present invention, in the image forming apparatus of the sixth aspect, the ink droplet collecting means is constituted by using the ink container which is also used as the collecting container, so that the direction toward the image forming object can be improved. Is characterized in that the flying direction of the charged ink droplet flying in a different direction is set so that the ink droplet directly enters the collection port of the ink container. In this image forming apparatus, charged ink droplets that fly in a direction different from the direction toward the image forming object are directly put into the collecting port of the ink container also serving as the collecting container and collected in the ink container.

The invention of claim 10 is the invention of claim 7, 8 or 9
In the above image forming apparatus, an accelerating means for accelerating the charged ink droplet toward the collection container is provided. In this image forming apparatus, the collection time of each ink droplet is shortened by accelerating the charged ink droplet toward the collection container by an acceleration unit.

According to an eleventh aspect of the present invention, in the image forming apparatus of the tenth aspect, an airflow generating means for generating an airflow in a direction for accelerating the charged ink droplet toward the collection container is provided as the acceleration means. It is assumed that. In this image forming apparatus, the charged ink droplet heading toward the collection container is accelerated by the airflow generated by the airflow generating means.

According to a twelfth aspect of the present invention, in the image forming apparatus of the tenth aspect, an electric field forming means for forming an electric field for accelerating the charged ink droplet toward the collection container is provided as the acceleration means. It is assumed that. In this image forming apparatus, the charged ink droplet heading toward the collection container is accelerated by the electric field generated by the electric field forming means.

According to a thirteenth aspect of the present invention, in the image forming apparatus of the twelfth aspect, the electric field forming means is provided with a pair of recovery accelerating electrodes provided side by side along a flight path of the charged ink droplet toward the recovery container. And a power supply for applying a voltage for forming an electric field in a direction for accelerating the charged ink droplets between the pair of recovery accelerating electrodes. In this image forming apparatus, a predetermined voltage is applied from the power supply to a pair of recovery accelerating electrodes provided side by side along a flight path of the charged ink droplet toward the recovery container, and an electric field for accelerating the charged ink droplet is applied. To form

According to a fourteenth aspect of the present invention, the charged ink droplet travels from the ink container to the through hole along a flight path.
A pair of deceleration electrodes for forming an electric field for decelerating the ink droplets is provided, and the flying direction of the charged ink droplet toward the through-hole and the collection flying direction of the charged ink droplet toward the collection container are in opposite directions. 13. The image forming apparatus according to claim 12, wherein the deceleration electrode is also used as the collection acceleration electrode. In this image forming apparatus,
An electric field for decelerating the ink droplet is formed by a pair of deceleration electrodes provided along a flight path of the charged ink droplet from the ink container toward the through hole. The deceleration electrode is also used as a recovery accelerating electrode, and an electric field for accelerating the charged ink droplet toward the recovery container is formed.

The invention of claim 15 is the invention of claim 7, 8 or 9
The flying path of the charged ink droplets collected in the collection container from the ink container toward the through hole and the collection flight path toward the collection container are different from each other. In this image forming apparatus, by making the trajectory toward the through-hole different from the recovery trajectory, it is possible to eject the ink droplets such that a plurality of charged ink droplets are simultaneously present in the trajectory. .

According to a sixteenth aspect of the present invention, in the image forming apparatus according to the fifteenth aspect, the image electrode is divided into a plurality of electrodes in a plane direction intersecting a flight direction from the ink container. By applying different voltages, the charged ink droplets ejected from the ink container fly while being shifted in a direction inclined from the initial ejection direction. In this image forming apparatus, a different voltage is applied to each of the image electrodes divided into a plurality of electrodes in a plane direction intersecting the flight direction from the ink container. By the electric field formed by each of the electrodes, the charged ink droplet ejected from the ink container is caused to fly while being shifted in a direction inclined from the initial ejection direction, so that the flight path toward the through-hole and the recovery flight path are made different. .

According to a seventeenth aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to the nozzle hole of the ink container than the image electrode. In the image forming apparatus, the auxiliary electrode is divided into a plurality of electrodes in a plane direction intersecting with a flight direction from the ink container. It is characterized in that the discharged charged ink droplets fly while being shifted in a direction inclined from the initial discharge direction.
In this image forming apparatus, an auxiliary electrode provided at a position closer to the nozzle hole of the ink container than the image electrode is divided into a plurality of electrodes in a plane direction intersecting a flight direction from the ink container. Apply different voltages. By the electric field formed by each of the electrodes, the charged ink droplet ejected from the ink container is caused to fly while being shifted in a direction inclined from the initial ejection direction, so that the flight path toward the through-hole and the recovery flight path are made different. .

The invention according to claim 18 is the image forming apparatus according to claim 15, wherein the ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of the ink container. And using, as the charging electrode, an electrode divided into a plurality of electrodes in a plane direction intersecting with a flight direction from the ink container, and applying a different voltage to each electrode, thereby charging the ink discharged from the ink container. The method is characterized in that an ink droplet flies while being shifted in a direction inclined from an initial ejection direction. In this image forming apparatus, a charging electrode arranged so as to sandwich an ink droplet to be ejected from a nozzle hole of the ink container is divided into a plurality of electrodes in a plane direction intersecting a flight direction from the ink container. Apply different voltages to the electrodes. By the electric field formed by each of the electrodes, the charged ink droplet ejected from the ink container is caused to fly while being shifted in a direction inclined from the initial ejection direction, so that the flight path toward the through-hole and the recovery flight path are made different. .

According to a nineteenth aspect of the present invention, in the image forming apparatus according to the fifteenth aspect, the inner peripheral surface of the image electrode has an axially symmetric shape with respect to a center axis of the through hole. The incident light is shifted from the central axis of the through hole. In this image forming apparatus, the charged ink is incident on the ink droplet while being shifted from the center axis of the through-hole, so that an electrostatic force is applied to the ink droplet in a direction intersecting the incident direction. Due to this electrostatic force, the charged ink droplets ejected from the ink container fly while being shifted in a direction inclined from the initial ejection direction, and the flight path toward the through hole and the collection flight path are made different.

According to a twentieth aspect of the present invention, in the image forming apparatus of the seventh aspect, the surface of the ink droplet collecting member with which the charged ink droplets come into contact is subjected to a water-repellent treatment. In this image forming apparatus, the surface of the ink droplet collecting member that contacts the charged ink droplets is subjected to a water-repellent treatment,
The ink droplet received by the member does not remain attached to the surface of the member, but flows to the collection container along the surface of the member due to its own weight or the like.

According to a twenty-first aspect of the present invention, in the image forming apparatus according to the ninth aspect, the recovery port of the ink container is located at a position away from the nozzle hole of the ink container so that the ink droplets are not ejected from the recovery port. It is characterized by having been formed. In this image forming apparatus, the recovery port of the ink container is formed at the predetermined position so that the ink droplet is not ejected from the recovery port.

According to a twenty-second aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode, and the recovery container is provided. 10. The image forming apparatus according to claim 7, wherein the auxiliary electrode is disposed on a side opposite to the image electrode, and the charged ink flying from the ink container toward the through hole as the auxiliary electrode. The present invention is characterized in that a single metal plate having a hole through which the droplet passes and a hole through which the charged ink droplet that flies backward toward the collection port of the collection container passes is used. In this image forming apparatus, by forming the two holes in an auxiliary electrode for forming an electric field that assists the deflection of the charged ink droplet, the charged ink droplet flies from the ink container to the through hole, The auxiliary electrode does not block the reverse flight of the charged ink droplet toward the collection port of the collection container. And
By using a single metal plate for the auxiliary electrode, an auxiliary electrode that is inexpensive, accurate, and excellent in mechanical strength can be manufactured.

According to a twenty-third aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode. 10. The image forming apparatus according to claim 7, wherein the auxiliary electrode is disposed on a side opposite to the image electrode, and the charged ink droplet to be collected in the collection container is formed in a nozzle hole of the ink container. The shape, arrangement, and applied voltage of the auxiliary electrode are set so that an electric field that accelerates in the direction is not formed. In this image forming apparatus, the charged ink droplets to be collected in the collection container are formed by the predetermined setting of the shape, arrangement, and applied voltage of the auxiliary electrode for forming an electric field that assists the deflection of the charged ink droplets. An electric field that accelerates in the direction of the nozzle hole of the ink container is not formed. By suppressing the formation of the accelerating electric field, the ink droplet can be collected at a position away from the nozzle hole of the ink container.

According to a twenty-fourth aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode. 10. The image forming apparatus according to claim 7, wherein the auxiliary electrode is disposed on the opposite side of the image electrode from the image electrode, wherein a charged ink droplet to be collected in the collection container is formed in a nozzle hole of the ink container. The shape of the auxiliary electrode, so that an electric field that reduces the speed in the direction to go is formed,
The arrangement and the applied voltage are set. In this image forming apparatus, the shape, arrangement and applied voltage of the auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet are determined by the predetermined setting of the charged ink droplet to be collected in the collection container. An electric field is formed that reduces the speed in the direction toward the nozzle holes of the ink container. The formation of the electric field enables the ink droplet to be collected at a position away from the nozzle hole of the ink container.

According to a twenty-fifth aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode. 10. The image forming apparatus according to claim 7, wherein the auxiliary electrode is disposed on a side opposite to the image electrode, and the charged ink droplet to be collected in the collection container is formed in a nozzle hole of the ink container. The shape, arrangement, and applied voltage of the auxiliary electrode are set such that an electric field that accelerates in a direction opposite to the direction is formed. In this image forming apparatus, the charged ink droplets to be collected in the collection container are formed by the predetermined setting of the shape, arrangement, and applied voltage of the auxiliary electrode for forming an electric field that assists the deflection of the charged ink droplets. An electric field is formed which accelerates in the direction opposite to the direction of the nozzle holes of the ink container. The formation of the electric field enables the ink droplet to be collected at a position away from the nozzle hole of the ink container.

According to a twenty-sixth aspect of the present invention, in the image forming apparatus according to the seventh or eighth aspect, of the charged ink droplets discharged from the ink container, the charged ink droplets to be adhered to the image forming object travel straight and fly. The image electrodes are provided so as to deflect the charged ink droplets collected in the collection container in a direction along the surface of the ink droplet flight control member. In this image forming apparatus, the charged ink droplets adhered to the image forming object fly straight and fly, so that even when the particle diameter of the ink droplet changes and its flight speed changes, the image forming object is Landing point does not change. By deflecting the charged ink droplets collected in the collection container in a direction along the surface of the ink droplet flight control member, the ink droplet flight control member does not block the ink droplets heading to the collection container. .

According to a twenty-seventh aspect of the present invention, in the image forming apparatus according to the twenty-sixth aspect, a ring-shaped first image electrode disposed so as to surround a through hole through which a charged ink droplet passes is provided as the image electrode. A second image electrode and a third image electrode disposed so as to face each other so as to sandwich a through hole through which the charged ink droplet passes on the upstream side in the ink droplet flight direction of the first image electrode; When the collected charged ink droplet is flying, a voltage having the same polarity as the charged polarity of the charged ink droplet is applied to the first image electrode and the second image electrode, and the voltage is applied to the third image electrode. It is characterized in that a voltage having a polarity opposite to the charging polarity of the charged ink droplet is applied. In this image forming apparatus, when the charged ink droplets to be collected in the collection container are flying, the first ring-shaped ink droplets are formed.
A voltage having the same polarity as the charged polarity of the charged ink droplet is applied to the image electrode and the second image electrode, and a voltage having a polarity opposite to the charged polarity of the charged ink droplet is applied to the third image electrode. The charged ink droplet is deflected in a direction along the surface of the ink droplet flying control member by an electric field formed by each electrode to which the voltage having the predetermined polarity is applied.

According to a twenty-eighth aspect of the present invention, in the image forming apparatus of the twenty-sixth aspect, an electric field is formed to deflect the charged ink droplets collected in the collection container in a direction along the surface of the ink droplet flight control member. In which a pair of collecting electrodes are provided. In this image forming apparatus, an electric field is formed by the pair of collecting electrodes so as to deflect the charged ink droplets collected in the collecting container in a direction along the surface of the ink droplet flying control member. The electric field accelerates the ink droplet toward the collection container, so that the ink droplet can be collected more quickly.

According to a twenty-ninth aspect, in the image forming apparatus of the twenty-eighth aspect, the recovery electrode is formed on the same member together with the image electrode.
In this image forming apparatus, by forming the recovery electrode and the image electrode on the same member, the relative positional accuracy between the two electrodes can be improved, and the manufacturing cost of both electrodes can be reduced. .

According to a thirtieth aspect of the present invention, in the image forming apparatus according to the twenty-eighth aspect, the charged ink droplet passing through the control electric field forming region by the image electrode travels between the flying path toward the image forming object and the collecting electrode. And a shield electrode. In this image forming apparatus,
By providing the shield electrode at the predetermined position, the electric field formed by the recovery electrode is prevented from acting on the charged ink droplet passing through the control electric field forming region by the image electrode and facing the image forming object. .

According to a thirty-first aspect of the present invention, in the image forming apparatus of the fifth aspect, an auxiliary electrode disposed so as to surround the through hole and a voltage for forming an electric field for assisting the deflection of the charged ink droplet are applied. And a power supply to be applied to the auxiliary electrode. In this image forming apparatus, the predetermined voltage is applied to the auxiliary electrode arranged so as to surround the through hole, thereby assisting the deflection of the charged ink droplet by the image electrode. With the assistance of this deflection, the ink droplet is easily deflected, so that the applied voltage (control voltage) to the image electrode required to deflect the ink droplet by a predetermined distance can be reduced. Further, even when the speed of the charged ink droplet discharged from the ink container is high, the deflection of the ink droplet according to the image information can be stably performed.

According to a thirty-second aspect of the present invention, in the image forming apparatus of the thirty-first aspect, the auxiliary electrode is formed on the same member together with the image electrode.
In this image forming apparatus, by forming the auxiliary electrode and the image electrode on the same member, the relative positional accuracy between the two electrodes is improved, and the manufacturing cost of the two electrodes can be reduced. .

A thirty-third aspect of the present invention is the image forming apparatus according to the thirty-first aspect, wherein said auxiliary electrode is provided at a position closer to a nozzle hole of said ink container than said image electrode. The shape, arrangement and applied voltage of the auxiliary electrode are set so that an electric field in the direction of accelerating the ink droplet is not formed in the flight path until the ink droplet reaches the control electric field forming region formed by the image electrode. It is characterized by having done. With this image forming apparatus, the charged ink droplets ejected from the ink container fly until reaching the control electric field forming region formed by the image electrode by the predetermined setting of the shape, arrangement, and applied voltage of the auxiliary electrode. In the path, an electric field for accelerating the ink droplet is prevented from being formed. The suppression of the formation of the accelerating electric field makes it easier to deflect the ink droplet, so that the voltage (control voltage) applied to the image electrode required to deflect the ink droplet by a predetermined distance can be reduced.
Further, even when the speed of the charged ink droplet discharged from the ink container is high, the deflection of the ink droplet according to the image information can be stably performed.

According to a thirty-fourth aspect of the present invention, in the image forming apparatus of the fifth aspect, there is provided an ink droplet deceleration means for decelerating a charged ink droplet flying from the ink container toward the through hole. It is. In this image forming apparatus, the ink droplets are easily deflected by decelerating the charged ink droplets flying from the ink container toward the through hole by the ink droplet deceleration means. Further, the applied voltage (control voltage) to the image electrode can be reduced.

According to a thirty-fifth aspect of the present invention, in the image forming apparatus according to the thirty-fourth aspect, an airflow generating means for generating an airflow in a direction for decelerating the charged ink droplet toward the through hole is provided as the ink droplet decelerating means. It is characterized by the following. In this image forming apparatus, the charged ink droplet heading toward the through hole is decelerated by the airflow generated by the airflow generating means. It can be easily decelerated.

According to a thirty-sixth aspect of the present invention, in the image forming apparatus according to the thirty-fourth aspect, an electric field forming means for forming an electric field for decelerating the charged ink droplet toward the through-hole is provided as the ink droplet reducing means. It is characterized by the following. In this image forming apparatus, the charged ink droplet heading to the through hole is decelerated by the electric field which is easily controlled by the electric field forming means, so that the ink droplet can be decelerated more accurately.

According to a thirty-seventh aspect of the present invention, in the image forming apparatus of the thirty-sixth aspect, the electric field forming means is provided with a pair of deceleration electrodes provided side by side along a flight path of the charged ink droplet toward the through hole. And a power supply for applying a voltage for forming an electric field for decelerating the ink droplet between the pair of deceleration electrodes.
In this image forming apparatus, the charged ink droplet toward the through hole is decelerated by an electric field formed by the pair of ring-shaped deceleration electrodes arranged along the flight path of the charged ink droplet toward the through hole.

(38) The image forming apparatus according to (37), wherein the ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of the ink container. Wherein the charging electrode is also used as a deceleration electrode of the pair of deceleration electrodes which is closer to a nozzle hole of the ink container. In this image forming apparatus, since the charging electrode is also used as the deceleration electrode near the ink droplet nozzle hole of the ink container among the pair of deceleration electrodes, the apparatus configuration is simplified.

In a thirty-ninth aspect of the present invention, an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to the nozzle hole of the ink container than the image electrode. An image forming apparatus, wherein the auxiliary electrode is also used as a deceleration electrode closer to the image electrode among the pair of deceleration electrodes. In this image forming apparatus, since the auxiliary electrode is also used as a deceleration electrode near the image electrode of the pair of deceleration electrodes, the configuration of the apparatus is simplified.

According to a fortieth aspect of the present invention, in the image forming apparatus of the thirty-seventh aspect, the image electrode is also used as a deceleration electrode of the pair of deceleration electrodes which is closer to the image forming object. is there. In this image forming apparatus, the image electrode is also used as the deceleration electrode closer to the image formation target among the pair of deceleration electrodes, so that the apparatus configuration is simplified.

According to a forty-first aspect of the present invention, in the image forming apparatus of the fifth aspect, the particle diameter of the charged ink droplet is set to such an extent that the charged ink droplet flying toward the through hole is decelerated by air resistance. It is characterized by the following. In this image forming apparatus, by setting the particle size of the charged ink droplet to the predetermined particle size, the charged ink droplet flying toward the through hole is decelerated by air resistance, so that the ink droplet is deflected. Therefore, the voltage (control voltage) applied to the image electrode required to deflect the light by a predetermined distance can be reduced. Further, even when the speed of the charged ink droplet discharged from the ink container is high, the deflection of the ink droplet according to the image information can be stably performed. The specific preferable range of the particle diameter of the ink droplet for the ink droplet to be decelerated by air resistance is 5 μm or less.

The invention according to claim 42 is the image forming apparatus according to claim 5, wherein a counter electrode disposed at a position facing the image forming object from a side opposite to the image electrode;
And a power supply for applying a voltage having a polarity opposite to the charging polarity of the charged ink droplet to the counter electrode. In this image forming apparatus, the electric field formed by the counter electrode applied with a voltage having a polarity opposite to the charging polarity of the charged ink droplet causes the electric charge formed by the image electrode to pass through the control electric field forming region by the image electrode toward the image forming object. Accelerate the ink drop. By accelerating the ink droplets, the speed of image formation can be increased.

According to a forty-third aspect of the present invention, in the image forming apparatus according to the fifth aspect, the flying path of the ink droplet is located at a position which does not hinder the flying of the charged ink droplet between the image electrode and the image forming object. A pair of deflection electrodes arranged so as to sandwich it,
A power source for applying a voltage to the deflection electrode for forming an electric field in a direction to deflect the ink droplets attached to the image forming object. In this image forming apparatus, an electric field formed by the pair of deflecting electrodes to which the predetermined voltage is applied deflects a charged ink droplet passing through a control electric field forming region formed by the image electrodes toward an image forming object. By deflecting the ink droplets, a plurality of dots of an image can be formed by ink droplets passing through one control electric field forming region.

According to a forty-fourth aspect of the present invention, in the image forming apparatus of the forty-third aspect, the intensity of the control electric field by the image electrode is made stronger than the intensity of the deflection electric field by the deflection electrode. In this image forming apparatus,
By making the intensity of the control electric field by the image electrode stronger than the intensity of the deflection electric field by the deflection electrode, the influence of the deflection electric field on the selective deflection of the charged ink droplet by the control electric field is reduced.

According to a forty-fifth aspect, in the image forming apparatus of the forty-third aspect, one of the pair of deflection electrodes is grounded,
It is characterized in that a voltage having a polarity opposite to the charging polarity of the charged ink droplet is applied to the other side. In this image forming apparatus, since a voltage is applied to only one of the pair of deflection electrodes, it is easy to control the applied voltage for forming the plurality of dots.

According to a forty-sixth aspect, in the image forming apparatus of the forty-third aspect, the deflection electrode is formed on the same member together with the image electrode.
In this image forming apparatus, by forming the deflection electrode and the image electrode on the same member, the relative positional accuracy between the two electrodes can be improved, and the cost of manufacturing the two electrodes can be reduced. .

According to a forty-seventh aspect, in the image forming apparatus of the fifth aspect, a shield electrode is provided on the ink container side and the image forming object side of the image electrode. In this image forming apparatus, by shielding the image electrode with the shield electrode provided on the ink container side and the image forming object side, the charged ink droplet that flies ahead passes through the control electric field forming region by the image electrode. Immediately after that, or immediately before a subsequent charged ink droplet enters the control electric field forming region, the voltage applied to the image electrode can be switched. Therefore, it is possible to increase the speed of image formation by shortening the discharge interval of the charged ink droplets.

The invention according to claim 48 is the image forming apparatus according to claim 47, wherein the shield electrode is grounded, and a pair of image electrodes arranged so as to face each other with the through hole interposed therebetween as the image electrodes. Wherein one of the pair of image electrodes is grounded, and a voltage having the same polarity as the charging polarity of the charged ink droplet is applied to the other. In this image forming apparatus, since the charged ink droplet is deflected in the direction of the grounded image electrode having the same potential as the shield electrode of the pair of image electrodes, the ink droplet adheres to the image electrode and Even if the shield electrode and the shield electrode are electrically connected, no excess current flows. Therefore, the risk of breaking the electric circuit for applying the voltage to each electrode is reduced.

According to a forty-ninth aspect, in the image forming apparatus of the forty-seventh aspect, the shield electrode is formed on the same member together with the image electrode. In this image forming apparatus, by forming the shield electrode and the image electrode on the same member, the relative positional accuracy between the two electrodes can be improved, and the manufacturing cost of the two electrodes can be reduced. .

According to a fifty aspect of the invention, in the image forming apparatus according to the fifth aspect, the charged ink droplets are converged in the through hole so as to surround a flight path of the charged ink droplet from the ink container toward the through hole. And a focusing electrode for forming an electric field. In this image forming apparatus, the charged ink droplet is converged in the through hole by an electric field formed by a focusing electrode provided so as to surround a flight path of the charged ink droplet from the nozzle hole of the ink container toward the through hole. . Due to the convergence of the ink droplets, even when the ejection angle of the ink droplets ejected from the ink container varies, the ink droplets are surely incident on the through-holes, and the ink droplets are selectively formed according to image information. Deflection can be reliably performed.

A fifty-first aspect of the present invention is the image forming apparatus according to the fifty-second aspect, wherein the inner diameter of the focusing electrode is larger than the inner diameter of the image electrode. In this image forming apparatus, since the inner diameter of the focusing electrode is larger than the inner diameter of the image electrode, the range of variation in the ejection direction of the ink droplet is widened.

According to a fifty-second aspect of the present invention, a grounded shield electrode is provided on the focusing electrode side of the image electrode.
0, wherein the focusing electrode is grounded. In this image forming apparatus, by grounding the focusing electrode, an unnecessary electric field is prevented from being formed between the focusing electrode and the shield electrode provided on the focusing electrode side, and the charged ink flowing toward the through hole is prevented. Droplet flight stabilizes.

The invention according to claim 53 is the image forming apparatus according to claim 50, wherein said ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of said ink container. And forming a potential difference between the charging electrode and the focusing electrode so that the charged ink droplets discharged from the nozzle holes of the ink container reach and adhere to predetermined positions on the image forming object. It is characterized by the following. In this image forming apparatus, by forming the predetermined potential difference between the charging electrode and the focusing electrode, the charged ink droplet discharged from the ink container reaches a predetermined position on the image forming target. Adhere to.

According to a fifty-fourth aspect of the present invention, in the image forming apparatus of the fifth to fifty-third aspects, at least one of the electrodes is formed on a flexible printed circuit (FPC) member. In this image forming apparatus,
At least one of the above-mentioned electrodes is provided with an inexpensive flexible printed circuit (F
(PC) member.

It should be noted that the image forming object in each of the above-mentioned claims includes not only a recording medium such as paper, but also an intermediate transfer body which temporarily carries an image to be transferred to the recording medium. In the invention of each of the above claims,
The speed of the charged ink droplet when passing through the control electric field forming region formed by the image electrode is preferably 2 m / sec or less.

[0067]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment. Although FIG. 1 shows only one nozzle hole, the actual device has a multi-nozzle structure in which a plurality of nozzle holes are formed in a line.

This apparatus comprises an ink container 10 and a charging electrode 2
0, a plate-shaped ink droplet flight control member 30 as ink droplet flight control means, and a counter electrode 40. A grounded base electrode 11, which is also used as a casing, is provided on the upper surface of the ink container 10 containing the ink 50 as a liquid image forming substance. In this base electrode 11, nozzle holes 12 having a predetermined diameter are formed in a line at a predetermined pitch. Further, the ink container 10 is provided with a discharge unit (not shown) for discharging ink droplets from the nozzle holes 12. This discharge means can be configured to use a piezo method using a piezoelectric (piezo) element, a bubble method, an electrostatic pressure method, an electrostatic suction method, or the like. In addition to these methods, the 1989 “THE FIFTH INTERNATIONAL CONGRESS ON ADVANCES IN
`` TRAVELING WAVE DROP GENERATOR FOR MULTI- '' proposed in the proceedings of `` NON-IMPACT PRINTING TECHNOLOGIES ''
Traveling Wave Drop Genera used in "NOZZLE CONTINUOUS INK JET" (hereinafter referred to as "conventional technology B")
tor (TWDG) method and spray method (WO95 / 158)
22, PCT / GB94 / 02692) or the like.

The charging electrode 20 has a diameter of 0.1 to 1.0 mm corresponding to each nozzle hole 12 on a metal plate having a thickness of 0.1 to 1 mm.
The plurality of holes 21 are formed. This hole 21
Are formed so that the tip of the ink column 51 ejected from each nozzle hole 12 of the ink container 10 is cut off to surround a place where an ink droplet 52 is formed. A voltage having a polarity opposite to the charging polarity of the charged ink droplet 52 is applied to the charging electrode 20 from a power supply (not shown). Charged electrode 2 to which this voltage is applied
0, a charge having a polarity opposite to the voltage is electrostatically induced in the ink column 51 ejected from the ink container 10, and the ink column 51 is discharged.
The charge remains on the ink droplet that has been cut off from the
Becomes The thickness of the charging electrode 20 is determined by the position where the ink column 51 extending from the nozzle hole 12 is cut, and the diameter of the hole 12 is determined by the amount of charge applied to the ink droplet 52 and the potential difference between the ink droplet and the charging electrode. . For example, when a charge amount of −9 μC / g is given to an ink droplet having a diameter of 30 μm, if the potential difference between the conductive ink column 51 and the charging electrode is 60 V, the diameter becomes 100 μm. Note that, instead of the metal plate as in the present embodiment, a ring-shaped electrode generally used in a nozzle head having a single nozzle hole may be used as the charging electrode 20. Further, as a method for charging the ink droplets, other known charging methods may be used instead of the method using electrostatic induction as in the present embodiment.

The charged ink droplets 5 are discharged from the nozzle holes 12 of the ink container 10 by the discharging means and the charged electrodes 21.
2 is configured as an ink droplet discharging means for discharging the ink droplets 2. By this ink droplet discharging means, the charged ink droplets 52 are simultaneously discharged from the plurality of nozzle holes 12 of the ink container 10.

FIGS. 2A and 2B are a cross-sectional view and a vertical cross-sectional view of the ink droplet flying control member 30, respectively. In the figure, the lead electrodes are omitted. The ink droplet flight control member 30 has a thickness of about 50 μm on both sides of a resin film (for example, a polyimide film) 34.
A copper foil of about 20 μm is applied, and the ring-shaped image electrode 3
A flexible printed circuit (FPC) member produced by exposing and etching the pattern of the first pattern and the pattern of the ring-shaped auxiliary electrode 32 on the back was used. In the center of the image electrode 31 and the auxiliary electrode 32 of the ink droplet flight control member 30, through holes 33 corresponding to the nozzle holes 12 are formed so that the charged ink droplets 52 from the nozzle holes 12 can pass through. You. In addition, a resin coating may be applied to the surface of each of the electrodes on which the pattern is formed, as necessary. Ring-shaped image electrode 31 of the ink droplet flight control member 30
Is mainly for forming a control electric field for selectively deflecting the charged ink droplet 52 according to the image information, and a control voltage that changes according to the image information is applied. The ring-shaped auxiliary electrode 32 forms an electric field for assisting the deflection of the charged ink droplet 52, and is applied with a constant voltage.

The counter electrode 40 is made of a conductive sucker for sucking and holding a paper 53 as an object to be image-formed.
A voltage having a polarity opposite to the charging polarity of the charged ink droplet 52 is applied from a power supply (not shown).

Further, in the apparatus of the present embodiment, the particle size of the ink droplet is set so that the charged ink droplet 52 flying from the ink container 10 toward the ink droplet flying control member 30 is decelerated by air resistance. The ink droplet 52 can be deflected with a low control voltage. In order to reduce the speed by the air resistance, it is preferable to set the particle diameter of the ink droplet to 5 μm or less.

The particle diameter, charge amount and initial velocity of ink droplets formed by various methods are generally 30 to 90 μm, respectively.
m, 3 to 15 μC / g, 5 to 20 m / sec. In the simulation of the present embodiment, the particle diameter of the charged ink droplet 52, the absolute value of the charge amount, and the initial velocity are respectively 5 to 60 μm,
１５15 μC / g and 5-20 m / sec.
In the simulations after the second embodiment, the particle size of the charged ink droplet 52 is 30 μm, and the charge amount is −9 μC /
g, the initial speed was assumed to be about 5 m / sec.

Next, a more specific configuration example of this embodiment will be described together with the results of simulation. In the simulation described below, particles having a radius r (m), a mass m (g), and a charge amount q / m (μC / g) are calculated by a numerical calculation based on the difference method at a position X0 (m) in a two-dimensional space. , Y0 (m) at an X-direction velocity Vx0 (m / sec) and a Y-direction velocity Vy0 (m / sec),
By solving the equation of motion expressed by the following equation using the X and Y components Fx and Fy of the sum of the seven forces acting on the particle, dt (sec)
Later a new position and velocity were determined.

Fx = m · αx Fy = m · αy x = x0 + Vx0 · dt + (1/2) αx · (dt) ² y = y0 + Vy0 · dt + (1/2) αy · (dt) ² Vx = Vx0 + αx ・ dt Vy = Vy0 + αy ・ dt

The following seven types of forces are considered in the above simulation. Electrostatic force due to the electric field formed at the position of the target particle by the voltage applied to the electrode. Image power based on the charge of the target particle. Electrostatic attraction with charged particles present around the target particle,
Electrostatic repulsion. gravity. Viscous resistance (air resistance). Adhesive force with electrodes (Van der Waaltz force). Repulsion force when colliding with electrodes and other toner.

In the configuration shown in FIG.
When simulating a change in the speed of the ink droplet 52 when the 0 μm ink droplet 52 is vertically launched at an initial speed of 5 m / sec, the speed becomes zero at a height of about 12 mm from the nozzle hole 12. In the present configuration example, the ink droplet 52 is controlled so as to enter the through hole 33 having a diameter of about 100 μm of the ink droplet flying control member 30 as described later. However, considering the variation of the ejection angle, the through hole is controlled. There is a possibility that the laser beam cannot be incident on the laser beam 33. For example, if the discharge angle from the nozzle hole 12 is inclined by 1 degree, the position is shifted by 200 μm in the horizontal direction at a distance of 12 mm, so that the nozzle deviates from the through hole 33. On the other hand, when the maximum speed is 1 mm, the lateral displacement can be suppressed to 17 μm. Therefore, even if the ink droplet having a diameter of 30 μm is shifted left and right, the through-hole 33 having a diameter of 100 μm can be obtained.
Can be made to enter.

FIG. 3 is a simulation result in which the highest point is obtained by changing the particle diameter and initial velocity of the ink droplet. FIG.
Symbols “×”, “▲”, “■” and “◆” in the table indicate initial speeds of 20 m / sec, 15 m / sec, 10 m / sec and 5 m, respectively.
The data for / sec is shown. FIG. 3 shows that when the particle diameter is 5 μm and the initial velocity is 15 m / sec or less, the highest point of the ink droplet is 1 mm or less.

Therefore, in the present embodiment, as shown in FIG. 1, an ink droplet flight control member 30 having an image electrode 31 and an auxiliary electrode 32 is arranged at a position 0.3 mm above the nozzle hole 12, and further above the nozzle hole 12. The counter electrode 40 is placed at a position of 0.4 mm.
The paper 53 supported by the paper 53 is arranged. 0 V was applied to the auxiliary electrode 32 and +600 V was applied to the counter electrode. Then, by applying -100 V to the image electrode, an ink droplet having a particle diameter of 5 μm discharged at an initial speed of 5 m / sec, charged at −9 μC / g by the charging electrode 20, is passed through the through hole 33 of the ink droplet flying control member 30. And is pushed back below the member 30. FIGS. 4A to 4O show simulation results in which the charged ink droplet 52 reversely moves.
By applying the same 0 V to the image electrode 31 as that of the auxiliary electrode 32, the charged ink droplet 52 passes through the through hole 33 of the ink droplet flight control member 30, and the charged ink droplet 52
Was adhered to the paper 53, and an image could be formed on the paper 53. FIGS. 5A to 5O show the charged ink droplets 5.
2 is a simulation result in which 2 passes through the through hole 33 and adheres to the paper 3. In this configuration example, the ink droplet flight control member 30 is affixed with a 17 μm (20 μm in simulation) copper foil on both sides of a 50 μm thick polyimide film.
The pattern of the auxiliary electrode 32 was formed on the back by exposure and etching. 4 and FIG. 5 has a time step of 50 μsec between each subdivision, and FIG. 1, FIG. 4 and FIG. 5 are upside down.

As described above, according to the image forming apparatus of the present embodiment, the through-hole 3 surrounded by the image electrode 31 of the ink droplet flight control member 30 and not easily affected by the surroundings by the electrostatic force.
3, a control electric field for controlling the deflection of the charged ink droplets 52 is formed. Therefore, even if the respective through holes are arranged close to each other, the control electric field for controlling the charged ink droplets discharged from each nozzle is reduced. Crosstalk is reduced. Therefore,
Compared to the case where ink droplets are deflected by using a conventional flat plate-shaped deflection electrode, it is easy to increase the number of nozzles with high density, and to reduce the deviation of the landing position of ink droplets due to the crosstalk. Can be. Further, according to the image forming apparatus of the present embodiment, the charged ink droplets 52 flying in the forward direction from the ink container 10 toward the ink droplet flying control member 30 by setting the particle diameter of the charged ink droplets 52 to a predetermined value or less.
Is decelerated by air resistance, the voltage (control voltage) applied to the image electrode 31 required to deflect the charged ink droplet 52 by a predetermined distance can be reduced. Moreover, even when the initial speed of the charged ink droplet 52 discharged from the ink container 10 is high, the deflection of the ink droplet 52 according to the image information can be stably performed.

[Embodiment 2] In the image forming apparatus shown in FIG.
It is conceivable to collect the ink droplets to be collected that have been pushed back from 0 downward, for example, by sending air to the ink container. When an airflow generating device is provided as a deceleration means for decelerating ink droplets ejected from the nozzle holes 12 at a high speed by a headwind (airflow), the headwind (airflow) becomes a collection wind as it is, which is very convenient. Yes, but it is less preferred because the wind is unstable and changes from place to place or from time to time. Although it is possible to wait for the ink droplet ejected upward to return only by gravity, it takes a very long time due to the large air resistance, and the image forming speed (recording speed) does not increase. Even if the diameter of the ink droplet is increased to 60 μm to reduce the contribution of air resistance, the time required for return is 0.66.
sec and still very long. Since the contribution of gravity is very small, almost the same result is obtained when the liquid is discharged in the horizontal direction and decelerated only by the air resistance. As mentioned above, air resistance, gravity,
It is theoretically possible but practically difficult to collect ink droplets by decelerating with wind. It is preferable to apply a more accurate and strong force to the ink droplets to collect them.

Therefore, in the image forming apparatus of the present embodiment,
The deceleration of the charged ink droplet 52 flying in the forward direction from the ink container 10 toward the ink droplet flight control member 30 using the electrostatic force generated by the electric field formed by the deceleration electrode, and the reverse (return) from the ink droplet flight control member 30 The charged ink droplet 52 flying in the direction is accelerated.

FIG. 6 is a schematic configuration diagram of an image forming apparatus according to the second embodiment. Note that, in FIG.
The same reference numerals are given to the same components as those of the embodiment shown in FIG. 1 and the configurations and functions thereof are also the same, and the description thereof will be omitted. Further, effects similar to those of the device of the first embodiment are omitted. In the apparatus shown in FIG. 6, a distance of 0.5 mm is provided between the charging electrode member 23 made of FPC having the ring-shaped charging electrode 22 and the ink droplet flying control member 30 above the base electrode 11 of the ink container 10. At intervals of deceleration electrodes 61A, 61A.
B are provided with deceleration electrode members 60A and 60B each composed of a pair of FPCs having B. Then, the deceleration electrode 61B is grounded, +1350 V is applied to the deceleration electrode 61A, the charge amount discharged at an initial speed of 5 m / sec is −9 μC / g, and the particle size is 30 μm.
The speed of the charged ink droplet 52 is controlled by the ink droplet flying control member 3.
The speed was reduced to about 1.4 m / sec before entering the through hole 33 of zero.
Then, similarly to the first embodiment, −1 is applied to the image electrode 31.
By applying 00V, the ink droplets 52 can be inverted and collected. On the other hand, by applying 0V to the image electrodes 31, the ink droplets 52 can pass through the through holes 33 and form an image on the paper 53. Was. The charged ink droplet 52 which is inverted by the control electric field formed by the image electrode 31 and comes out from the through-hole 33 downward is formed by the deceleration electrode 6 which is also used as a collection acceleration electrode.
It was accelerated by the opposite acceleration electric field formed between 1A and 61B and returned to the ink container 10. The time required for collecting the ink droplets is the same as that of the charged ink droplets 52
Is discharged, the through-hole 3 of the ink droplet flight control member 30 is formed.
3 is about 150 μsec, the time from entering the through-hole 33 to exit is about 200 μsec, and the time from exiting the through-hole 33 to returning to the ink container 10 is about 150 μsec, for a total of about 500 μsec. Was. When the resolution of an image is 300 dpi, one dot (one line) is 500 μsec.
, So the printing speed is about 17 ppm.

The ink droplets 52 collected in the ink container 10 are directly collected in the ink container 10 after a flight of 0.5 msec in time and a distance of about 1 mm, so that there is little contamination in the air. . Further, a collecting device including a garter, a pipe, a motor, a filter, and the like is not required. Further, since only one ink droplet 52 exists in the air for one nozzle hole 12, mutual interference between the ink droplets does not occur. Of course, interference between adjacent dots is conceivable, but if the image electrodes 31 and the nozzle holes 12 are arranged in a staggered manner as shown in FIG.
It is 300 μm, and no mutual interference occurs. FIG.
Means that an image electrode 31 having an inner diameter φ of about 160 μm has a width W of about 2 m.
m and pitch P = 84.5 μm (corresponding to a resolution of 300 dpi)
Shows an example of a staggered arrangement.

[Embodiment 3] FIG. 8 is a schematic configuration diagram of an image forming apparatus according to a third embodiment. In FIG. 8, the same parts as those of the apparatus shown in FIGS. 1 and 6 of the above embodiment are denoted by the same reference numerals, and their configurations and functions are also the same. Further, effects similar to those of the device of the first embodiment are omitted.

In the apparatus shown in FIG. 8, the deceleration electrodes 61A, 61B
And the charging electrode member 23 and the ink droplet flying control member 30
Is reduced to 0.500 mm, and the charging electrode 22 of the charging electrode member 23 is also used as the deceleration electrode 61A in FIG.
The auxiliary electrode 32 was also used as the deceleration electrode 61B. Then, +1350 V is applied to the charging electrode 22 and +
Similar results were obtained by applying 600V, 0V to the auxiliary electrode 32, and 0V and -100V to the image electrode 31 according to image information. 9 (a) to 9 (o) and FIG.
(A) to (o) respectively show an operation mode for forming an image on the paper 53 (hereinafter, referred to as “image forming mode”) and an operation mode for collecting the charged ink droplets 52 into the ink container 10 (hereinafter, “collection mode”). ).
7 is a simulation result showing a state of flight. The simulation of each figure shows that the charged ink droplet 52 is
2 is performed from the point where it comes out of the charging area.

In this embodiment, the charged ink droplets 52
In order to maintain the same charge amount, the inner diameter of the charging electrode 22 was made wider than in the case of the second embodiment to reduce the electric capacity between the charging electrode 22 and the ink column 51. Further, +600 V applied to the counter electrode 40 is not essential. Since the charged ink droplet 52 for forming an image has a speed of 1.5 m / sec when entering the through hole 33 of the ink droplet flying control member 30, the voltage applied to the counter electrode 40 is accelerated by setting it to 0V. Even if it is flown without flowing, as shown in the simulation result of FIG.
0 μsec becomes 700 μsec).

In this embodiment, when a common ground electrode is disposed on the back side (lower side in FIG. 8) of the polyimide film and a ring-shaped image electrode is disposed on the front side, the image electrode 31 is disposed as shown in FIG. It is possible to easily increase the density by arranging in a staggered manner. Further, as will be described in an embodiment described later, when an image electrode is arranged on the back side and a half-moon-shaped deflection electrode is arranged on the front side, the density can be similarly increased in a staggered arrangement.

[Embodiment 4] FIG. 12 is a schematic configuration diagram of an image forming apparatus according to a fourth embodiment. FIG.
In this embodiment, the same reference numerals are given to the same parts as those of the above-described embodiment shown in FIGS.
Further, effects similar to those of the device of the first embodiment are omitted.

In the apparatus shown in FIG. 12, the auxiliary electrode 32 also serving as the deceleration electrode 61B of the apparatus shown in FIG. 8 is omitted, and the image electrode 31 is directly opposed to the charged electrode, and +1400 is applied to the charged electrode 22.
V, +600 V for the counter electrode 40 and 0 V /
By applying -100 V, an image could be formed on the paper 53 and ink droplets could be collected in the same manner as in the apparatus of FIG. FIG.
3 (a) to 3 (o) and FIGS. 14 (a) to 14 (o) show the ink droplets 5 in the image forming mode and the collecting mode, respectively.
2 is a simulation result showing a state of flight 2; The simulation in each figure is performed from the place where the charged ink droplet 52 comes out of the charged area by the charged electrode 22.

[Fifth Embodiment] FIG. 15 is a schematic configuration diagram of an image forming apparatus according to a fifth embodiment. Note that FIG.
In this embodiment, the same reference numerals are given to the same parts as those of the above-described embodiment shown in FIGS.
Further, effects similar to those of the device of the first embodiment are omitted.

In the apparatus shown in FIG. 15, an image electrode 31 is provided on the back side (lower side in the figure) of the ink droplet flight control member 30, and a pair of deflection electrodes 35A and 35B are provided on the front side (upper side in the figure). The voltage applied to each of the left and right deflection electrodes 35A and 35B is set to +
By changing the voltage to 30 V / −30 V and −30 V / + 30 V, the landing point of the charged ink droplet 52 that has passed through the control electric field forming region by the image electrode 31 is approximately 70 μm from the center.
It could be deflected to the left and right. FIG. 16 (a)
17 (a) to 17 (o) and FIGS. 17 (a) to 17 (o) are simulation results showing how the ink droplet 52 flies when deflected to the left in the figure and when deflected to the right in the figure, respectively.

In the apparatus of the present embodiment, the deflection electrode 3
When the deflection voltage applied to 5A and 35B is lowered to deflect about 42 μm for one dot of 600 dpi, 200 d
An image of 600 dpi can be printed by the nozzle holes 12, the through holes 33, the image electrodes 31, and the high-voltage ICs for pi, and the number of expensive high-voltage ICs can be reduced to ３.

[Embodiment 6] In the apparatuses according to the first to fifth embodiments, the next ink droplet cannot be ejected until the ink droplet 52 ejected from the nozzle hole 12 returns to the nozzle hole 12.
The image forming speed (recording speed) cannot be increased. Therefore, in the apparatus of the present embodiment, the ink droplet flying control member 3
The image forming speed is improved by making the outward path of the ink droplet heading toward 0 and the return path where the ink droplet for recovery returns a separate path.

In the apparatus according to the third embodiment (see FIG. 8), when the nozzle hole 12 was shifted to the left by 30 μm from the center, as shown in the simulation result of FIG. The flight path of the ink droplets to be collected once entering and returning to 33 was shifted rightward in the figure and landed approximately 45 μm right from the center.
It is probable that the landing point shifted in this way because the through-hole 33 was accelerated to the right by receiving an electrostatic force from the left to the center in the drawing. In order to further increase the shift amount, a simulation was performed by dividing the auxiliary electrode 32 into left and right and applying -50 V to the left auxiliary electrode 32A and +50 V to the right auxiliary electrode 32B instead of grounding. As a result, as shown in FIG. 19, the rightward electrostatic force of the negatively charged ink droplet 52 entering the through hole 33 increased, and the ink droplet 52 landed about 80 μm to the right of the center.

FIG. 20 is a schematic configuration diagram of an image forming apparatus according to the sixth embodiment. In FIG. 20, the same components as those of the embodiment shown in FIGS. 1 and 8 are denoted by the same reference numerals, and their configurations and functions are also the same. In addition, the first
Effects similar to those of the device according to the embodiment are also omitted. In the apparatus shown in FIG. 20, the nozzle holes 12 are provided off the center based on the simulation results shown in FIG.
Then, electrodes 32A and 32B divided into two in the horizontal direction in the figure were provided as auxiliary electrodes, and different voltages were applied between the two electrodes. Further, since the landing point of the ink container 10 is different from the nozzle hole 12, the recovery hole 13 is provided separately from the nozzle hole 12.

According to the apparatus of this embodiment, the ink droplets 52
The recording speed could be increased 2.5 times by setting the ejection interval of 500 μsec to 200 μsec. This 200μsec
Is the time from the time when the preceding ink droplet is ejected from the nozzle hole 12 to the time when it shifts from the through hole 33 in the left-right direction and emerges downward. At this time, the charge amount of the ink droplet is -9 μm.
At C / g, the speed of the ink droplet 52 when entering the through hole 33 is 1.3 m / sec, and the interval between the ink droplets at that time is about 260
μm and mutual interference between ink droplets need not be taken into account. Instead of shifting by the auxiliary electrodes 32A and 32B, the decelerating electrode serving also as the charging electrode may be divided into right and left and a potential difference may be provided to shift the flying ink droplets in the same manner to separate the forward path and the return path. Further, the shift may be performed by a magnetic force, gravity, wind power, or the like instead of the electrostatic force.

[Embodiment 7] FIG. 21 is a schematic configuration diagram of an image forming apparatus according to a seventh embodiment. Note that FIG.
In this embodiment, the same reference numerals are given to the same parts as those of the above-described embodiment shown in FIGS. Further, effects similar to those of the device of the first embodiment are omitted.

In the apparatus shown in FIG.
A metal plate having a thickness of 0.1 to 1.0 mm and a hole 20A having a diameter of 0.1 to 1.0 mm corresponding to the nozzle hole 12 and a hole A0B corresponding to the recovery hole 13 was used. The plate thickness of the charging electrode 20 is determined by the position where the ink column 51 extending from the nozzle hole 12 is cut, and the hole diameter is determined by the amount of charge applied to the ink droplet and the potential difference between the ink and the charging electrode. For example, when a charging amount of −9 μC / g is applied to the ink droplet 52 having a diameter of 30 μm, if the potential difference between the conductive ink column 51 and the charging electrode 20 is 60 V, the diameter becomes 100 μm.

The auxiliary electrode 62 provided separately from the ink droplet flight control member 30 has a diameter of 0.25 mm on a metal plate having a thickness of 0.1 mm.
The inlet hole 62D and the outlet hole 62E having a diameter of 0.2 mm were formed apart from each other by 0.2 mm. In the case of a multiple nozzle, a slit-shaped hole may be formed instead of a circular hole. For example, thickness 50μ
A copper foil having a thickness of 17 μm (20 μm in the simulation) was attached to the surface of a polyimide film having a length of about m, and the pattern of the auxiliary electrode was exposed to light and then etched.
It may be manufactured by opening a slit having a width of 36 mm and a width of 0.10 mm with a laser (for example, a YAG laser) at a distance of 0.18 mm.

The image electrode 31 and the deflection electrode 35 are provided integrally with the ink droplet flight control member 30 made of FPC.
Each is divided into image electrodes 31A and 31B and deflection electrodes 35A and 35B in the horizontal direction in the figure. The image electrodes 31A and 31B and the deflection electrodes 35A and 35B are 17 μm thick on both sides of a 50 μm thick polyimide film.
(In the following simulation, it was set to 20 μm.) A copper foil was adhered, the pattern of the deflecting electrode was exposed on the front side, and the image electrode pattern was exposed on the back side, and then etched. Produced. Also,
As the counter electrode 40, a conductive belt that also serves to transport the paper 53 was used.

The auxiliary electrode 62 is connected to the charge electrode 20 by a voltage of 0.1.
It was located 5 mm above. An ink droplet flying control member 30 is arranged 0.1 mm above the auxiliary electrode 62, and is placed 0.4 m above the member.
The counter electrode 40 was arranged m above. Then, a charged ink droplet 52 having a diameter of 30 μm and a charge amount of −9 μC / g is moved upward from the position 0.5 mm to the left of the center of the charging electrode 20 in FIG. Injection was performed at an initial velocity of 1.6 m / sec in the X direction, and the flight trajectory after that was simulated.

FIG. 22 shows that the deflection electrodes 35A and 35B are not provided, the charging electrode 20 has + 1200V, and the auxiliary electrode 62 has 0V.
V, -200 V for image electrodes 31A and 31B, counter electrode 4
Charged ink droplet 5 when +600 V is applied to 0
2 is a simulation result of a flight trajectory of FIG. Note that FIG. 9 shows a simulation performed only after the charged ink droplet 52 has protruded from the charged electrode, and the time interval (one frame) between each drawing is 50 μsec. As can be seen from FIG. 22, the charged ink droplet 52 reaches an intermediate point between the charged electrode 20 and the auxiliary electrode 62 50 μsec after jumping out of the hole 20A of the charged electrode 20, and approaches the auxiliary electrode 62 after 100 μsec to reach 150 μsec. Later, the auxiliary electrode 62
After 200 μsec, it passes therethrough and enters a control electric field forming region formed by the image electrodes 31A and 31B and the auxiliary electrode 62. In this area, since -200V is applied to the upper image electrodes 31A and 31B and 0V is applied to the lower auxiliary electrode 62, the negatively charged ink droplet 52 is applied.
Receives electrostatic force in the downward direction. Therefore, at this time, the speed is still 1.5 m / sec in the Y direction (upward direction in the figure), but is strongly decelerated in the control electric field, and further reversed to have a speed in the −Y direction. Become like The velocity component in the X direction (right direction in the figure) does not change more than the initial velocity of 1.6 m / sec. After jumping out of the hole 20A of the charging electrode 20, 2
After 50 μsec, it approaches the ink droplet flight control member 30, and after 300 μsec, it comes directly below the through-hole 33 of the member 30. However, here, the speed in the Y direction is almost 0 m / sec.
Turn to the lower right, 450μse
c After entering the outlet hole 62E of the auxiliary electrode 62,
After passing through here, it is accelerated and then reaches the charging electrode 20 after 650 μsec. The velocity in the Y direction at the time of this landing is-
It is 4.8 m / sec. Since the distance between the point at which the charged electrode 20 protruded and the point at which the charged electrode 20 returned was 1.0 mm, a hole 20B was opened at the landing point of the charged electrode 20, and the ink droplet 52 to be collected was passed through. The ink can be returned to the recovery port 13 of the ink container 10 sufficiently away from the hole 12. 1.00m by changing the discharge angle, initial speed, etc.
It is easy to obtain distances of more than m.

FIG. 23 shows a simulation result obtained by changing the voltage applied to the right image electrode 31A of the pair of image electrodes shown in FIG. 22 from -200V to -50V.
Other conditions are the same as those in FIG. As can be seen from FIG. 23, the flight path of the ink droplet 52 is not different from that of FIG. 22 until 200 μsec after passing through the auxiliary electrode 62, but the control electric field surrounded by the auxiliary electrode 62 and the image electrodes 31A and 31B is reduced. Unlike the case of the above, the deceleration electric field in the region formed by the image electrode 31A and the auxiliary electrode 62 is weak. Therefore, even after 300 μsec, it has a velocity of 0.7 m / sec in the Y direction, is accelerated in the Y direction by the electric field between the ink droplet flight control member 30 and the counter electrode 40 through the through-hole 33, and
After μsec, the paper lands on the paper on the counter electrode 40.

FIG. 24 shows a simulation result obtained by adding the deflection electrodes 35A and 35B and applying -200V to the image electrodes 31A and 31B and 0V to the deflection electrodes 35A and 35B. Other conditions are the same as those in FIG. In this case, the flight path of the charged ink droplet 52 is almost the same as in FIG. 22 having no deflection electrode, and is 1.0 m to the right of the pop-out point.
Land at a distance of m.

FIG. 25 shows a simulation result obtained by changing the voltage applied to the right image electrode 31A from -200V to -50V while the voltage applied to the deflection electrodes 35A and 35B is kept at 0V. Other conditions are the same as those in FIG. In this case, the ink droplet 52 passes through the through hole 33 and lands on the paper on the counter electrode 40 as in FIG.

FIG. 26 is a simulation result obtained by changing the voltage applied to the deflection electrode 35A (left side in the figure) to + 30V and the voltage applied to the deflection electrode 35B (right side in the figure) to -30V. Other conditions are the same as those in FIG. In this case, since the electrostatic force acts on the negatively charged charged ink droplet 52 in the through hole 33 between the deflection electrodes 35A and 35B in the left direction in the figure, the flight path of the ink droplet 52 is slightly leftward. shift. As a result, the landing point on the counter electrode 40 is about 6
Shift to the left by 0 μm.

FIG. 27 shows a simulation result obtained by changing the voltage applied to the deflection electrode 35A (left side in the figure) to -30 V and the voltage applied to the deflection electrode 35B (right side in the figure) to +30 V. Other conditions are the same as those in FIG. In this case, the electrostatic force acts on the negatively charged charged ink droplet 52 in the through hole 33 between the deflecting electrodes 35A and 35B in the right direction in the figure, so that the flight path of the ink droplet 52 is slightly to the right. shift. As a result, the landing point on the counter electrode 40 is about 6
Shift right by 0 μm.

Since the shift amount of the ink droplet 52 can be adjusted by the voltage applied to the deflection electrodes 35A and 35B, for example, four adjacent dots are formed by one nozzle hole and a pair of image electrodes. If adjusted to 150dp
i number of image electrodes, high voltage IC for control), 600d
You can get a print of pi. As a result, not only can the use of expensive high-voltage ICs be reduced to one-fourth,
With a 50 dpi image electrode array, a 600 dpi print with high resolution can be obtained.

[Embodiment 8] In the apparatus of the seventh embodiment, as shown in the simulation results of FIGS. 22 and 23, the flight path of the charged ink droplet 52 is
In order to switch from the recovery flight path to the flight path toward the recording paper by passing through the through hole 33 interposed between the image electrodes 31A and 31B, the voltage applied to the image electrode 31A (left side in the figure) is changed from -200 V to- It is necessary to change 150V to 50V. Since high-voltage ICs that can change 150 V are very expensive, if they can be used for general-purpose 24 V IC control, the cost will be greatly reduced. The reason why the voltage change amount for switching the flight path is also required to be 150 V is as follows.
It is considered that the speed of the ink droplet 52 was not sufficiently reduced before entering the control electric field forming region. Therefore, looking at the speed 200 μsec after the injection just into the control electric field forming region, v (x) = 1.6 m / sec, v (y) = 1.5 m / s
ec. Compared to the initial speed, the vertical direction (vertical direction in the figure) is reduced by 70%, but the horizontal direction (horizontal direction in the figure) is not changed at all.

When the time change of the flight speed of the ink droplet 52 is examined in detail, as shown in FIG. 28, the horizontal speed is accelerated once in the middle, then decelerated again, and returns to the original speed. This result indicates that an electric field that accelerates in the horizontal direction was present in the flight path. Note that the symbols “記号” and “■” in FIG. 28 indicate data of the flight speed in the horizontal direction and the flight speed in the vertical direction, respectively. Also, the charging electrode 20
FIG. 29 shows the electric field formed between the ink droplet flight control member 30 and the electric field lines. FIG. 2 showing the distribution of the lines of electric force and the flying state of the ink droplet 52.
In comparison with No. 3, 10 minutes after ejection from the charging electrode 20
It can be seen that from 0 μsec to 150 μsec, the film was accelerated by receiving an electrostatic force in the horizontal direction (X direction).

Therefore, in this embodiment, the auxiliary electrode 62 is provided so that an acceleration electric field for accelerating the ink droplet in the horizontal direction (X direction) is not formed in the flight path from the charging electrode 20 to the ink droplet flight control member 30. Was. Specifically, the entrance hole 62D and the exit hole 62E of the auxiliary electrode 62 are widened so that the left end of the entrance hole 62D is located directly above the left end of the emission hole 20A of the charging electrode 20. The thickness of the auxiliary electrode 62 was also changed from 100 μm to 20 μm. Other configurations are
This is the same as FIG. FIG. 30 shows the distribution of the electric flux lines after this change. As can be clearly seen from FIG. 30, there is no horizontal (X-direction) accelerating electric field in the flight path from the charging electrode 20 to the ink droplet flight control member 30. FIG. 3 shows the speed change of the ink droplet 52 at this time.
As shown in FIG. 1, the speed in the horizontal direction (X direction) is also decelerated without being accelerated on the way. Also, comparing FIG. 28 with FIG. 31, it can be seen that the degree of deceleration in the vertical direction hardly changes regardless of the change in the shape of the auxiliary electrode 62.

FIG. 32 shows that the charging electrode 20 has +1400 V,
0 V for the auxiliary electrode 62 and -10 for the image electrodes 31A and 31B.
When 0 V is applied to the deflection electrodes 35A and 35B and +600 V is applied to the counter electrode 40, the diameter is 2.0 m / sec in the horizontal direction (X direction) and 4.9 m / sec in the vertical direction (Y direction). Charged ink droplet 52 of 30 μm and charge amount of -9 μC / g
Is a simulation result of the flight trajectory of the ink droplet 52 after being ejected from the charging electrode 20. Note that FIG. 9 shows a simulation performed only after the charged ink droplet 52 has protruded from the charged electrode, and the time interval (one frame) between each drawing is 50 μsec. Comparing FIG. 32 with FIG. 31, 200 μs
c) Lateral speed when entering the control electric field forming area is 1.1
m / sec. 1.6m / se in case of above Fig.28
c. Also, the vertical speed has been reduced to 1.0 m / sec. In the case of FIG. 28, it was 1.5 m / sec. The cause of this decrease in vertical speed was that the initial vertical speed was 5.0 m.
This is because the voltage applied to the charging electrode 20 was increased from + 1200V to + 1400V. Under the same conditions as in the case of FIG. 28, the ink droplets 52 hit the ink droplet flying control member 30, and this is a result of re-adjusting the conditions. Since the speed of entering the control electric field forming region has decreased, the control voltage required to deflect the flight path of the ink droplet 52 toward the paper on the counter electrode 40 should have been smaller than 150V.

FIG. 33 shows that the voltage applied to the image electrode 31A is
It is a simulation result performed by changing 50V from 100V to -50V. Other conditions are the same as those in FIG. From FIG. 32, it can be seen that the ink droplet passes through the through hole 33 of the ink droplet flight control member 30 and adheres to the paper on the counter electrode 40. Also in this case, similarly to the case of FIGS. 26 and 27 of the seventh embodiment, the deflection electrodes 35A, 35A are used.
A voltage of +/− 30 V is applied to B and the landing point on the paper is +/−
It can deflect by 60 μm.

[Embodiment 9] In the apparatus according to the seventh embodiment (see FIG. 21), the charging electrode 20 is 0.58 mm from the charging electrode 20.
The auxiliary electrode 62 is arranged on the upper side, and 0.10 m from the auxiliary electrode 62.
m, an ink droplet flight control member 30 is disposed
The counter electrode 40 is placed 0.40 mm above the charging electrode 2.
The ink droplet 52 having a diameter of 30 μm and a charge amount of −9 μC / g is moved upward from the position 0.5 mm to the left from the center of 0 toward the upper right.
Injection was performed at an initial velocity in the direction of 4.9 m / sec and an initial velocity in the X direction of 2.0 m / sec, and the subsequent flight trajectory was simulated.

FIG. 34 shows that +1400 V,
0V for auxiliary electrode 62, -20 for image electrodes 31A and 31B
It is a simulation result when 0V, 0V is applied to the deflection electrodes 35A and 35B, and + 600V is applied to the counter electrode 40. Other conditions are the same as those in FIG. As shown in FIG. 34, the ink droplet 52 is deflected downward in the control electric field forming area and returns to the ink container 10. The ink droplet 52 lands at a position 0.95 mm to the right of the ejection point. The flight speed at the time of 600 μsec immediately before landing is 1.7 m / sec in the horizontal direction,
It was -4.4 m / sec in the vertical direction. Increase the horizontal speed,
Unless the vertical speed is reduced, the landing point cannot be moved away. In order to keep the landing point away, it is necessary to increase the horizontal acceleration electric field and weaken the vertical acceleration electric field in the recovery flight path. When the electric field formed between the charging electrode 20 and the ink droplet flying control member 30 is viewed from the electric lines of force, FIG.
It looks like 5. A horizontal acceleration electric field exists above the auxiliary electrode 62, but no horizontal acceleration electric field exists at all in a wide space between the auxiliary electrode 62 and the charging electrode 20, and only a strong vertical acceleration electric field exists.

Therefore, in the present embodiment, +1400 V is applied to the auxiliary electrode 62C (the auxiliary electrode on the right side in FIG. 21) located on the collection path side of the ink droplet 52, and
The configuration was such that the potential difference between C and the charging electrode 20 was 0V. The auxiliary electrode 62 is a polyimide film having a thickness of about 50 μm, a copper foil having a thickness of 17 μm (20 μm in the simulation) attached, and a pattern of the auxiliary electrode is exposed to light and then etched to a length of 0.36 mm. ,
It was manufactured by opening a slit having a width of 0.10 mm with a laser (for example, a YAG laser) at a distance of 0.18 mm. The configuration of other parts is the same as that of FIG.

FIG. 36 shows an electric field formed between the charging electrode 20 and the ink droplet flying control member 30 in the device of this embodiment. A strong horizontal acceleration electric field exists over a wide range between the auxiliary electrodes 62B and 62C and the charging electrode 20, and an upper half of the electric field has an upward electric field (deceleration electric field) and a lower half has a downward electric field (acceleration electric field). Electric field), between which there is a narrow region that is neither accelerated. Here, if ink droplets are applied at a large horizontal speed, it should fly horizontally to a great distance.

FIG. 37 shows that, in the device of this embodiment, the charging electrode 20 has +1400 V, the auxiliary electrodes 62A and 62B have 0V, the auxiliary electrode 62C has 1400V, and the image electrodes 31A and
It is a result of simulating the flying state of the ink droplet when 50 Vsec is applied to one frame when -200 V is applied to 31B and +600 V is applied to the counter electrode 40. As can be seen from FIG. 37, after the ink droplet 52
At the time point when 0 μsec had elapsed, the horizontal speed was 4.6 m / sec and the vertical speed was -1.7 m / sec. Calculating the landing point of the ink droplet 52 in the case of this simulation, it was 2.2 mm to the right of the ejection point, which was more than twice that in the case of FIG. This effect is due not only to the vertical (Y-direction) velocity dropping from -4.4 m / sec to -1.7 m / sec, but also to the horizontal (X-direction) velocity falling below 1.7 m / sec. It depends on the speed being increased to .6m / sec. Incidentally, when the speed in the horizontal direction (X direction) is the same, the landing point drops to 1.9 mm.
The speed in the horizontal direction (X direction) was increased because a horizontal acceleration electric field was generated there. It is apparent from the distribution of the electric flux lines in FIG. 36 that the horizontal acceleration electric field was generated as a result of applying a higher voltage to the auxiliary electrode 62B at the same height by the auxiliary electrode 62C.

FIG. 37 (n) and FIG. 37 (n) show 650 μsec after the ink droplet 52 was ejected from the charging electrode 20.
In FIG. 37 (o) after elapse of μsec, it is displayed that the ink droplet that has escaped to the right of the diagram enters from the left, and therefore cannot be used as it is. Since the positions of the ink droplets 52 in FIGS. 37 (n) and (o) correspond to the neutral electric field region in FIG. 36, it is considered that the ink droplets 52 to be collected proceed as they are without being affected by the electric field. In FIG. 37, the simulation was performed assuming that the charging electrode 20 extends to the right end. However, when the charging electrode 20 is limited to the left end, the same result is obtained by applying 0 V to the auxiliary electrode 62C. .

[Embodiment 10] In the apparatus of the ninth embodiment, even if the ink droplet to be collected is brought to the neutral electric field region, the landing point does not extend so much. 1.7m / sec downward due to the downward acceleration electric field
It was because of the speed. Since the ink droplet to be collected is always accelerated downward by the control electric field formed by the image electrodes 31A and 31B, it is necessary to pass the upwardly accelerated electric field region to eliminate the downward speed.

Therefore, in the present embodiment, the voltage applied to the auxiliary electrode 62C on the recovery path side is increased from + 1400V to + 2100V.
V to raise the potential of the auxiliary electrode to 700 V from the charged electrode 20
I raised it. Other conditions were the same as in the ninth embodiment. Other configurations were the same as those in FIG.

FIG. 38 shows an electric field (lines of electric force) formed between the charging electrode 20 and the ink droplet flying control member 30 in the device of this embodiment. Here, the charging electrode 2
0 at + 1400V, auxiliary electrodes 62A and 62B at 0V, auxiliary electrode 62C at + 2100V, image electrodes 31A and 31B
-200V is applied. As can be seen from FIG. 38, an electric field is generated between the auxiliary electrode 62C on the recovery path side and the charging electrode 20 to accelerate the negatively charged ink droplet 52 upward. This electric field should cancel out the velocity in the −Y direction given by the electric field generated by the image electrodes 31A and 31B.

FIG. 39 shows that, in the apparatus of this embodiment, +1400 V is applied to the charging electrode 20, 0 V is applied to the auxiliary electrodes 62A and 62B, 2100V is applied to the auxiliary electrode 62C, and the image electrodes 31A and
It is a result of simulating the flying state of the ink droplet when 50 Vsec is applied to one frame when -200 V is applied to 31B and +600 V is applied to the counter electrode 40. As can be seen from FIG. 39, after the ink droplet 52 has been ejected from the charging electrode 20, 45
From the time when 0 μsec elapses to the time when 550 μsec elapses, the Y-direction speed is -1.67 m / sec, -0.62 m / sec, and 0.0.
The speed is greatly reduced to 5 m / sec. The speed of the ink droplet 52 in the X direction at the time when 550 μsec has elapsed is 5.81 m / sec. When the flight path after this is calculated, when the vehicle travels 0.83 mm horizontally, it rises 0.13 mm and rises to the auxiliary electrode 62C.
Has adhered to. That is, this result indicates that the Y-direction accelerating electric field is unnecessary after canceling out the −Y-direction velocities given by the image electrodes 31A and 31B. It should be noted that FIG.
(M) to (o)) cannot be used as they are as in the case of FIG.

In FIG. 39, it is assumed that both the charging electrode 20 and the auxiliary electrode 62C are cut off at the right end of the drawing, and that there is no electric field to the right. After calculating the subsequent flight path in sec, the aircraft landed 15.8mm to the right of the launch point.

When it is desired to land closer, it is preferable to narrow the upward accelerating electric field region (specifically, shorten the auxiliary electrode 62C a little) and relax the degree of deceleration. For example, the velocity in the Y direction when leaving the electric field region is -0.4 m.
Assuming that the speed in the X direction is 5.81 m / sec at / sec, the landing point is 7.7 mm to the right of the emission point. FIG. 40 shows the landing point (distance from the nozzle hole 12) when the Y direction (vertical direction) velocity Vy is changed. From the result of FIG. 40, it can be seen that the landing point can be arbitrarily selected. In FIG. 40, before entering the non-electric field area, the ink droplet 52 is
It moves 1.5mm in the direction (horizontal direction).

[Embodiment 11] In the apparatus of the tenth embodiment (see FIG. 21), a positive voltage is applied to the negatively charged ink droplet 52 which is projected obliquely upward from the hole 20A of the charging electrode 20 at high speed. In the electric field formed by the charged charging electrode 20 and the upper grounded auxiliary electrode 62, the auxiliary electrode 62 and the image electrode 31 are decelerated by receiving an electrostatic force in the opposite direction.
A, and enters the control electric field forming region sandwiched between 31B. When a negative voltage is applied to the pair of image electrodes 31A and 31B, the ink droplet 52 further receives an electrostatic force in the −Y direction, and the speed in the Y direction decreases.
With the speed in the Y direction, it is collected diagonally to the lower right. On the other hand, a positive voltage is applied to the left image electrode 31B, and a right image electrode 31A
When a negative voltage is applied to the through hole 33 (the relative potential difference between the two image electrodes may be applied), an electrostatic force is applied to the upper left to
And land on the paper 53 on the counter electrode 40 to form dots.

FIG. 41 shows an electrode arrangement in a simulation performed as a comparative example of the present embodiment. In this simulation, since the simulation was performed only after the charged ink droplet 52 jumped out of the hole of the charging electrode 20, the ink container 10 and the charging electrode 20 are not shown. The paper 53 is also omitted.

FIG. 42 shows that the auxiliary electrode 6 is placed 0.58 mm above the charged electrode 20 in the recovery mode of the configuration shown in FIG.
2 and the ink droplet flight control member 30 is placed 0.10 mm above the auxiliary electrode 62, and 0.40 mm from the member 30.
The counter electrode 40 is disposed on the upper side, and the diameter is 30 μm from the position 0.5 mm to the left of the center of the charging electrode 20 toward the upper right,
An ink droplet 52 having a charge amount of −9 μC / g is applied at an initial velocity of 4.9 m in the Y direction.
/ sec, a simulation result of the flight trajectory after injection at an initial velocity of 2.0 m / sec in the X direction. + To the charging electrode 20
1400V, 0V for auxiliary electrode 62, image electrodes 31A, 3
The flight positions of the ink droplets 52 simulated by applying -100V to 1B, 0V to the deflection electrodes 65A and 65B, and + 600V to the counter electrode 40 are shown every 50 μsec. The ink droplet is deflected downward in the drawing in the control electric field forming area and returns to the ink container 10.

FIG. 43 shows a simulation result in the image forming mode. The conditions were set to the same as those in FIG. 42 except that -76 V was applied to the image electrode 31A and -124 V was applied to the image electrode 31B. In this case, the charged ink droplet 52 is deflected in the control electric field forming region, flies upward in the drawing, and lands on the counter electrode 40.

Although the particle diameter of the ink droplet 52 is relatively stable, there is still a fluctuation of about 10%. Therefore, considering the margin, the particle size of the ink droplet 52 is changed from 30 μm to ± 4 μm (1
(3.3%) The case where it increased or decreased was simulated. FIG.
Is a simulation result in the recovery mode when the particle size of the ink droplet 52 is changed from 30 μm to 34 μm. Other conditions were set in the same manner as in the case of FIG. Originally, it must be deflected to the right in the drawing in the control electric field forming area to form a recovery route. However, when entering the control electric field forming area (after 150 μsec), the Y-direction speed is too high and the through-hole 33 is formed before bending. Into the through hole 3
3 and adhered to the counter electrode 40. This dot becomes a very large defect because it becomes a background stain. FIG.
Is a simulation result in the collection mode when the particle size of the ink droplet 52 is reduced from 30 μm to 26 μm. Other conditions were set in the same manner as in the case of FIG. This time, when entering the control electric field forming region, the deflection was applied too quickly (strongly) and landed on the central auxiliary electrode 62B without entering the recovery route. In this case, this does not affect the image, but if ink is accumulated here, the auxiliary electrode 62B
There is a possibility that the ink droplets that should pass close to the printer may come into contact and be caught and the image may not be displayed. As described above, a problem occurs in the recovery mode regardless of whether the particle size is large or small.

FIG. 46 shows that the diameter of the ink droplet 52 is 30 μm.
Is a simulation result in an image forming (printing) mode when the distance becomes from 34 μm. Other conditions were set in the same manner as in the case of FIG. Printing was successful, but the landing point was larger than when the particle size was 30 μm, and shifted by 61 μm to the right in the figure. Since the interval between one dot when printing at 600 dpi is 42 μm, this greatly affects the image. FIG. 47 shows that the particle size of the ink droplet 52 is 30 μm.
10 is a simulation result in an image forming (printing) mode when the distance is reduced from m to 26 μm. Other conditions were set in the same manner as in the case of FIG. In this case, since it was attracted too quickly (strongly) to the image electrode 31A (left) on the left side in the figure, it collided with the ink droplet flight control member 30 and could not pass through the through-hole 33, so that printing could not be performed after all. As described above, even in the image forming (printing) mode, when the particle diameter is increased or decreased from 30 μm to 4 μm, the landing point is greatly changed or printing is not performed. As described above, in the case of the comparative example,
There is no room in the flight path for normal printing and collection, and the change in speed due to the change in particle size cannot be absorbed.

Therefore, in the image forming apparatus of the present embodiment,
As shown in the schematic configuration diagram of FIG. 48, the ejection from the nozzle hole 12 of the ink container 10 is stopped obliquely, the ejection is performed horizontally (perpendicular to the paper 53), and printing is performed without deflection, and collection is performed. Was deflected by 90 ± 45 degrees to strike a collecting wall (not shown), from which it was dropped by its own weight and collected. In the case of such a configuration, in the image forming mode, the flight course does not change even if the flight speed increases or decreases due to a change in particle diameter or the like. Further, in the collection mode, even if the deflection angle changes due to an increase or decrease in the flight speed, it can be collected by hitting either the left or right wall (the right surface of the auxiliary electrode 36 or the left surface of the ink droplet flight control member in the figure).

FIG. 49 shows an electrode configuration used in the simulation of the apparatus of this embodiment. Since the effect of gravity on the flight of the ink droplet 52 is negligible, it rotates 90 degrees,
The actual horizontal direction was taken vertically.

FIG. 50 shows a simulation result (50 μsec per frame) when the ink droplet 52 having a standard particle diameter of 30 μm is collected in the apparatus of this embodiment. The image electrode 31A of the second ink droplet flight control member 36 at the lower left in the figure
And -24 V are applied to the ring-shaped image electrode 31B on the back surface of the first ink droplet flight control member 30 thereon,
When +24 V is applied to the image electrode 31C of the second ink droplet flight control member 36 at the lower right in the figure, the charged ink droplet 52 charged to -9 .mu.C / g causes the image electrode 31A, 3
Speed 0.8 in the control electric field forming region surrounded by 1B and 31C.
Entering at 5 m / sec, receiving a rightward electrostatic force in the figure, turning right, the ink collecting groove (the first ink droplet flying control member 3)
0 and a wall (a wall of both members 30 and 36) between the second ink droplet flying control member 36). After that, it is dropped and collected by its own weight. The rightward direction in FIG. 50 is the lower side in the vertical direction of the actual apparatus, that is, the direction of gravity.

FIG. 51 shows a simulation result (50 μsec per frame) when an image is formed by the standard ink droplet 52 having a particle diameter of 30 μm in the apparatus of this embodiment. The voltage applied to all of the image electrodes 31A, 31B, and 31C is set to 0 V, and printing is performed by passing straight through the control electric field forming region. The speed of the charged ink droplet 52 entering the control electric field forming region at a speed of 0.9 m / sec drops to 0.6 m / sec, but when the charged ink droplet 52 enters the through hole 33 of the ink droplet flying control member 30, the deflection electrode 35 Accelerated at + 100V. Further, when passing through the through-hole 33, it is accelerated at +800 V of the counter electrode 40, and lands at the counter electrode 40 at a speed of 3.2 m / sec or more when 650 μsec elapses after the injection.

FIG. 52 shows a simulation result (50 μsec per frame) when the small ink droplet 52 having a particle diameter of 26 μm is collected in the apparatus of the present embodiment. In this case, since the influence of the air resistance is relatively large, the speed when entering the control electric field forming region is further reduced to 0.75 m / sec. As a result, the image electrode 31C approaches the image electrode 31C (lower right in the figure) earlier.
3), and moves to the upper right, adheres to the surface of the ink droplet flight control member 30 above the ink collecting groove (the right side in the actual apparatus shown in FIG. 48), and is collected.

FIG. 54 shows a simulation result (50 μsec per frame) when a large ink droplet 52 having a particle diameter of 34 μm is collected in the apparatus of this embodiment. In this case, contrary to the above, the influence of the air resistance becomes smaller, and the speed at the time of entering the control electric field forming region is higher at 0.93 m / sec. As a result, it became difficult to receive the electrostatic force in the right direction in the figure, and it adhered to the left side (the upper side in the actual device shown in FIG. 48) of the ink collecting groove (the surface of the second ink droplet flight control member 36).

As described above, in the apparatus of this embodiment, when the electrostatic force is applied to the ink droplet 52 flying vertically (actually horizontal) to deflect it to the right (actually downward) and collect it, the particle diameter becomes 13 Even if it is increased or decreased by%, it can be collected in the ink collecting groove. Since the walls of the ink collecting grooves (the surfaces facing the first and second ink droplet flight control members 30 and 36) are subjected to a water-repellent treatment (lipophilic treatment), the water-based ink is repelled. And fall by its own weight and collected.

FIG. 55 shows a simulation result (50 μsec per frame) when an image is formed with a small ink droplet 52 having a particle size of 26 μm in the apparatus of this embodiment. In this case, since the influence of air resistance was relatively large and the flight speed was low, the landing time at the counter electrode 40 was extended to 950 μsec from 650 μsec at 30 μm, but the landing point was not changed. Since the moving distance of the paper during this period is about 15 μm, there is no effect on the image. Note that the image forming speed is 10 pp
m, and the paper transport speed was 50 mm / sec.

FIG. 56 shows a simulation result (50 μsec per frame) when an image is formed with a large ink droplet 52 having a particle diameter of 34 μm in the apparatus of this embodiment. In this case, the landing time is about 5 times as compared with the case where the particle size is 30 μm.
Although it is 0 μsec earlier, there is no deviation of the landing point.

As described above, the ink droplets 52 are moved in the vertical direction in the drawing (the horizontal direction in the actual apparatus shown in FIG. 48) as in the present embodiment.
In the image forming apparatus in which the ink droplets 52 are ejected and travel straight without being deflected in the image forming (printing) mode, the image can be formed (printed) without any problem even if the particle diameter of the ink droplet 52 increases or decreases.

[Embodiment 12] In the case of the device of the eleventh embodiment, the image electrodes 31A and 31C and the image electrodes 31
Since B must be formed on another substrate (FPC), it is expected that not only the cost will increase but also the gap management between these electrodes will be very difficult. There is no problem when the potentials of the adjacent image electrodes 31A and 31C are 0V / 0V in the image forming mode, but when one of the potentials is -24V / + 24V in the recovery mode and the other is 0V / 0V in the image forming mode, It is deflected to the recovery mode and the landing point shifts. These two problems are described in the third embodiment.
This does not occur in the apparatus described above, but is not preferable because the ejection point of the ink droplet 52 and the landing point of the collected ink droplet are almost the same.

Therefore, in the apparatus according to the present embodiment, as shown in FIG. 57, necessary electrodes (image electrode, auxiliary electrode, and recovery electrode) are formed on the same substrate (FPC) to reduce costs and to manage gaps. Made unnecessary. Further, the potentials of the electrodes on the surface from which the charged ink is ejected are all the same so that crosstalk is eliminated, and the collecting point is far away from the ejection point so that the ink can be easily collected.

In FIG. 57, the ink droplet 52 is ejected in the horizontal direction and is charged, and the charged ink droplet 52 is decelerated between the charging electrode 22 and the grounded auxiliary electrode 32 by electrostatic force.
Is the auxiliary electrode 32 and the image electrode 31 at a speed of 1 m / sec or less.
Then, as shown in the figure, it enters the control electric field forming region of the hole sandwiched and surrounded. In the image forming mode, since the image electrode 31 is also at 0 V, there is no electric field in this area, and the straight line passes through the through hole 33 and is accelerated by the voltage of the counter electrode 40 to be accelerated.
Land on. On the other hand, in the collection mode, since a voltage having the same polarity as that of the charged ink droplet 52 is applied to the image electrode 31,
It is decelerated and stopped in the through-hole 33 which is a control electric field forming region, accelerates in the opposite direction, and goes out of the through-hole 33. At this time, when a high voltage of opposite polarity is applied to the upper and lower collecting electrodes 37, the charged ink droplet 52 moves downward and is collected.

FIG. 58 shows the electrode arrangement used in the simulation of the apparatus of this embodiment. In FIG. 58, the simulation was performed only after the charged ink droplet 52 protruded from the charged electrode 22.
0 and the charging electrode 22 are not shown. The paper 53 is also omitted. Also, for the sake of simulation, the right direction was set to the direction of gravity. As shown in FIG.
An ink droplet flight control member 30 composed of an FPC including an auxiliary electrode 32, a recovery electrode 37 and an image electrode 31 is placed 0.70 mm above the counter electrode 40, and a counter electrode 40 is placed 0.40 mm above the member 30. The charged ink droplet 52 having a diameter of 30 μm and a charge amount of −9 μC / g is moved upward from the center of Y.
Injection was performed at an initial velocity in the direction of 5.0 m / sec and an initial velocity in the X direction of 0.0 m / sec, and the subsequent flight trajectory was simulated.

FIG. 59 shows a case where +1330 V is applied to the charging electrode 22, 0 V is applied to the auxiliary electrode 32, 0 V is applied to the image electrodes 31, 0 V is applied to the recovery electrodes 37 A and 37 B, and +800 V is applied to the counter electrode 40 in the apparatus of this embodiment. Simulation result of image formation (printing) mode (50 μse per frame)
c). Note that FIG. 59 is upside down from the electrode configuration diagram of FIG. 58. In the simulation of FIG. 59, the charged ink droplet 52 enters the through hole 33 at a point of time 300 μsec after the ejection, and proceeds straight as it is,
At the time point c, the light exits from the through hole 33 and faces the counter electrode 40. This result is the same as in the third embodiment (collection electrode 37).
A, 37B).

FIG. 60 shows a simulation result (50 μs per frame) of the recovery mode in which only the voltage applied to the image electrode 31 was changed from 0 V to −24 V in the apparatus of this embodiment.
c). The other conditions were set in the same manner as in the case of FIG. In this case, the charged ink droplet 52 is 300 μs after ejection.
After the passage of c, the light enters the through-hole 33, where it is decelerated and inverted, and after 400 μs, it passes through the through-hole 33 and returns to the starting point of the charging electrode 22. This result is the same as in the third embodiment. The simulation results of FIGS. 59 and 60 are basically the same as those of the third embodiment.

In the apparatus according to the present embodiment, unlike the apparatus according to the third embodiment, when the ink droplet 52 to be collected comes out from the through hole 33, another force is applied to deflect the ink droplet 52 by about 90 degrees to the collection course. You may comprise so that it may be carried. The other force may be given by the flow of air (airflow = wind), but since it tends to be unstable, it is preferable to provide an electrostatic force. Therefore, in a modified example of the apparatus of the present embodiment, after the ink droplet to be collected has passed through the through hole 33 and 500 μsec has elapsed after the ejection, the left and right collection electrodes 37 are set.
The voltage applied to A and 37B was changed from 0 V to ± 1.5 kV, and a strong horizontal electric field was applied to the space between the charging electrode 20 and the ink droplet flight control member 30.

FIG. 61 shows the recovery electrodes 37A, 37A at a point 500 μsec after the injection in the apparatus of this embodiment.
The applied voltage of B is changed from 0 V to -1.5 kV and +1.
It is a simulation result (50 microseconds per frame) of the collection mode changed to 5 kV. The other conditions were set in the same manner as in the case of FIG. In this case, the ink droplet 52 to be collected is strongly flowed to the left (gravity direction) in the figure, and hits the left wall of the simulation area at a time point of 700 μsec after the ejection. Thereafter, it is easy to further move in the horizontal direction and guide it to an appropriate recovery port.

As described above, the ink drops to be collected can be placed on the collection course by the electrostatic force.
The following new problems have been found to occur. When a collection voltage of ± 1.5 kV is applied to the left and right collection electrodes 37A and 37B, the ink droplets passing through the through holes 33 and proceeding straight to the counter electrode 40 in the image forming (printing) mode are added to the collection electrodes 37A and 37B.
The course of the electric field formed by A and 37B acts and the landing point shifts. The recovery voltage is applied to all the through holes at the same time.

FIG. 62 shows that, in the apparatus of this embodiment, the collection electrodes 37A and 37A are 500 μsec after the injection.
The applied voltage of B is changed from 0 V to -1.5 kV and +1.
9 is a simulation result (50 μsec per frame) of an image forming (printing) mode changed to 5 kV. The other conditions were set in the same manner as in the case of FIG. From the result of FIG. 62, it is apparent that the charged ink droplet 52 still flying toward the counter electrode 40 is largely shaken to the left side in the figure (vertically downward in the actual apparatus). Understand. This side effect is caused by adding a shield electrode 38 on the counter electrode 40 side of the ink droplet flight control member 30 and
8 can be solved by grounding. This shield electrode 38
Can be easily formed by coating with a conductive paint.

FIG. 63 shows that, in the apparatus of this embodiment, the above-mentioned grounded shield electrode 38 is provided, and 500 μs
This is a simulation result (50 μsec per frame) of the image forming (printing) mode in which the applied voltage to the collection electrodes 37A and 37B was changed from 0 V to −1.5 kV and +1.5 kV at the point where c elapsed. The other conditions were set in the same manner as in the case of FIG. In this case, the charged ink droplet 52 that has passed through the through hole 33 is clearly traveling straight. In addition, as a precautionary measure, when the applied voltage to the collecting electrodes 37A and 37B was kept at 0 V, a simulation was performed to compare the landing points, but no difference of 1 μm occurred.

[Embodiment 13] In the apparatus according to the twelfth embodiment, the printing ink droplet and the ink droplet to be collected can be separated with a small head and a low (24 V) control voltage. The next ink droplet cannot be ejected until the recovery electric field (very strong) is extinguished, ie, until the recovery electric field (extremely strong) disappears. From the simulation result of FIG. 61, it is estimated that the ejection interval of the ink droplet 52 is required to be 700 μsec or more.

Therefore, in the present embodiment, as shown in FIG. 64, the charged ink droplet 52 is decelerated by electrostatic force, and both the printing ink droplet and the ink droplet to be collected are advanced, and an image is formed based on the image information. The ink droplet 52A to be collected deflected by the control electric field formed by the electrode 31 and the auxiliary electrode 32 is applied to the collection plate 63, dropped by gravity, collected, and the non-deflected printing ink droplet 52B is moved straight to the paper 53. It was configured to print on top.

In the apparatus of the present embodiment, in order to estimate an appropriate ejection interval of the ink droplet 52, the image signal application timing of printing / collection (non-deflection / deflection) is changed to change the ink droplet 5.
2 was simulated. FIG. 65 shows the electrode arrangement used in the simulation. In this simulation, the particle size was 30 μm and the charge amount was -15 μC / g.
Of the charged ink droplets 52 in the Y direction Vy = 4.0 m / sec, X
The conditions were set so that injection was performed at the directional speed Vx = 0.0 m / sec. Note that FIG. 65 is a diagram inverted upside down from the simulation configuration in the twelfth embodiment.

FIG. 66 shows the charged electrode 2 of the device of this embodiment.
0V is applied to 0, the image electrode 31 is also grounded (0V), and the flying state of the ink droplet 52 in the image forming (printing) mode in which the ink droplet 52 moves straight and lands on the counter electrode 40 is simulated at 100 μsec per frame. The result. FIG. 67 shows the flight state of the ink droplet 52 in the collection mode in which −24 V is applied to the image electrode 31 to bend the ink droplet 52 leftward (vertically downward in the actual apparatus) and land on the collection plate 63. This is a result of a simulation performed at 100 μsec per frame. The initial speed is 4.0 m / sec. However, since the speed is reduced by receiving an electrostatic force from the electric field formed by the potential difference between the charging electrode 20 and the image electrode 31 and the auxiliary electrode 32, the speed when entering the through hole 33 is reduced. The speed is about 1.2 m / sec in the image forming mode and about 1.1 m / sec in the collecting mode. In the image forming mode, since there is almost no electric field up to the counter electrode 40, the light beam advances straight and hits the counter electrode 40 at a speed of about 1.0 m / sec. The landing position is exactly the same as the position from which the light was emitted (the position 200 μm from the left end in FIG. 65). On the other hand, in the recovery mode, the control electric field formed between the auxiliary electrode 32 (0 V) and the image electrode 31 (−24 V) in the through hole 33 receives the electrostatic force in the −X direction and reduces the speed in the −X direction. Then, it continues to fly while turning to the left in the drawing (vertically downward in the actual device) and hits the recovery plate 63.
At this time, the speed in the Y direction is about 0.9 m / sec, and the speed in the X direction is about-
It was 0.5 m / sec.

In order to increase the recording speed in the apparatus of the present embodiment, it is necessary to continuously eject the ink droplets 53. At that time, the preceding ink droplet is collected by the image electrode 31 by -2.
When 4 V is applied, the subsequent printing ink droplets are also affected by this and the landing point shifts to the left. It is not clear how much deviation is a problem, but here, it is assumed that one dot formed on the paper 53 has a size of 10% of 60 μm.
It is assumed that there is no problem if it is within 6 μm. Diameter 3
The 0 μm ink droplet forms a dot having a diameter of 60 μm on the paper 53.

The data indicated by the symbol “◆” in FIG. 68 indicates that the control voltage (image signal) applied to the image electrode 31 is changed from −24 V to 0.
The result of simulating the shift amount of the landing point by changing the time for switching to V is shown. From the results shown in FIG. 68, within 200 μsec after the ejection, in other words, at a position about 70 μm or more away from the ink droplet flight control member 30 (see FIG. 66), the control voltage is changed from the collection signal (−24 V) to the print signal (0 V). If it changes to, the deviation of the landing point is the target 6μm
It can be seen that it fits within.

The data indicated by the symbol “◆” in FIG. 69 indicates that, when the succeeding ink droplet is to be collected, the control voltage when the preceding printing ink droplet has passed through the through-hole 33 of the ink droplet flying control member 30 is reached. It shows a result of simulation as to whether switching of (image signal) is permitted. From the result of FIG. 69, it is found that the position is set to 550 μsec after the ejection and the position is set to 200 μm from the ink droplet flying control member 30 after the ejection.
It can be seen that the switching should be performed at a point more than m (see FIG. 66).

Based on the results of the above simulation, 3
Assuming that ink drops continue to be collected, printed and collected,
The control voltage (image signal) was switched from −24 V to 0 V when 200 μsec had elapsed after the second ink droplet was ejected, and from 0 V to −24 V when 550 μsec had elapsed. It has shifted by 15 μm. Therefore, the switching time of the control voltage is further increased by 50 in front of the ink droplet flying control member 30.
μsec earlier, later 50 μsec later, 150 μsec and 6
When switching was performed in 00 μsec, the deviation of the landing point was within 6 μm. That is, the time difference between the ink droplets 52 is changed from about 700 μsec in the case of the apparatus of the twelfth embodiment to 450 μsec.
μsec. If three ink droplets continue in the order of printing → collection → printing, 300 μsec and 35
Even when switching was performed at 0 μsec, that is, at an interval of only 50 μsec, it was OK.

[Embodiment 14] FIG. 70 is a schematic structural view of an image forming apparatus according to a fourteenth embodiment. In the apparatus of the present embodiment, the influence of the control electric field (image electric field) does not leak out from the through hole 33 of the ink droplet flying control member 30, and the control voltage (image signal) can be switched immediately before and after the member 30. In order to achieve this, the entire surface of the front surface (front) and the back surface (rear) of the member 30 is uniformly thin (20 in the simulation).
(thickness: μm) Shield electrodes 39A and 39B were provided, and the shield electrodes were grounded. These shield electrodes 39A, 39B
Can be easily formed by coating a conductive paint at the end of the manufacturing process of the ink droplet flight control member 30 made of FPC. In FIG. 70, the same parts as those of the apparatus shown in FIGS.
Since their configurations and functions are the same, their description will be omitted. Further, effects similar to those of the device of the first embodiment are omitted.

FIG. 71 shows a simulation result of the recovery mode in the apparatus of this embodiment. The electrode configuration and the ink droplet characteristics in this simulation are the same as those in FIG. 65 of Embodiment 13 except that shield electrodes 39A and 39B having a thickness of 20 μm are provided on both surfaces of the ink droplet flight control member 30. It was set similarly. In addition, the simulation result in the image forming mode is the same as that of the thirteenth embodiment, and thus the description is omitted.

In the simulation of FIG. 71, the left electrode was grounded as the auxiliary electrode 32, and the right electrode was applied with -24 V as the image electrode 31 (see FIG. 65). Even if +24 V is applied as 31 and the left electrode is grounded as the auxiliary electrode 32, it is electrically equivalent. However, in this case, the ink droplet 52A to be collected hits the left electrode for some reason and stops, and the ink droplet 52A spreads through the through-hole 33 to form the shield electrode 39.
A, 39B, there is a high possibility that a large current flows here and the control IC is destroyed. On the other hand, when the left electrode is grounded, even if the ink droplet 5
Even if 2A adheres and is connected to the shield electrodes 39A and 39B, it is safe.

In the apparatus according to the present embodiment, as in the thirteenth embodiment, assuming that the preceding or succeeding ink droplet is to be collected, a control voltage (image signal) is provided before and after the ink droplet flight control member 30. ) Was changed from -24V to 0V and from 0V to -24V at different timings to simulate the deviation of the landing point. The results are shown in FIGS. 68 and 69 as data with the symbol “□”. Obviously, it is significantly improved as compared with the case where the shield electrodes 39A and 39B are not provided. Based on this result, as in the case of the thirteenth embodiment, assuming collection → printing → collection, the control voltage (image signal) is reduced by −280 μsec and 380 μsec after the injection.
When the simulation was switched from 24 V to 0 V and from 0 V to −24 V, the deviation of the landing point was within 6 μm (see FIG. 72).

According to the simulation results shown in FIG. 72, when the preceding ink droplet enters the through hole 33 of the ink droplet flying control member 30, a control voltage (image signal) for the preceding ink droplet is applied, and the preceding ink droplet is applied to the through hole. It can be seen that the control voltage (image signal) can be switched to the control voltage for the subsequent ink droplet at the moment of passing through 33. The interval of 100 μsec between the ink droplets is almost equal to the time for the ink droplet to cross the ink droplet flight control member 30. The speed during this period is about 1.2 m / sec, and the width of the ink droplet flight control member 30 is 140 μm (100 μm excluding the shield electrodes 39A and 39B).

The above assumption that the shield electrodes 39A and 39B are not affected by the voltage applied to the electrodes inside the ink droplet flight control member 30 outside the ink droplet flight control member 30 is based on the following ink droplets. It can be confirmed by electric fields (lines of electric force) inside and outside the flight control member 30.

FIGS. 73, 74, and 75 respectively show the electric fields (the lines of electric force) above the ink droplet flight control member 30, inside the through hole 33, and below when the −24 V is applied to the image electrode 31. Is the distribution of

Referring to FIG. 73 and FIG. 74, the lines of electric force are vertical above the ink droplet flight control member 30 until immediately before entering the through hole 33 of the member 30, and almost horizontal when entering the through hole 33. Has changed to This means that the negatively charged ink droplet 52 moves straight to the position immediately before the ink droplet flight control member 30 and enters the through hole 33 and shifts to the left by receiving an acceleration in the left direction in the figure. Further, FIG.
75 and FIG. 75, the ink droplet to be collected that has flowed to the left immediately after leaving the ink droplet flight control member 30 receives a further weaker leftward force, but there is no electric field acting on the printing ink droplet that goes straight, After that, no electric field exists up to the counter electrode 40,
It can be seen that both ink droplets continue to fly while maintaining the velocity at the time of leaving the ink droplet flight control member 30 (slightly reduced by gravity and air resistance).

[Embodiment 15] Based on the results of the above-described Embodiment 14, by adding the shield electrodes 39A and 39B to both surfaces of the ink droplet flying control member 30, the distance between ink droplets becomes 100 μm.
It became clear that it can be shortened to sec. As a result, high-speed printing became possible. For example, if a 600 dpi head is used, one line of 600 dpi (= 25.4 mm /
(600 = 42.3 μm) can be recorded in 100 μsec, and the recording speed becomes 423 mm / sec. This is a high speed equivalent to 80 ppm.

However, in many cases, the nozzle holes 12 cannot be arranged in a staggered manner in an actual ink jet. Although they must be arranged in a straight line, high resolution cannot be achieved in this case. In the case of an image of 600 dpi, the pitch between dots is 42.3 μm, but the required dot diameter is (√
2) about 60 μm. The diameter of the ink droplet required to realize this dot diameter is 30 μm. Diameter 3
The nozzle hole 12 must have an inner diameter of at least 80 μm in order to allow 0 μm ink droplets to pass without difficulty. Also, the electrode width of the image electrode 31 must be at least 20 to 30 μm.

Therefore, in the present embodiment, as shown in FIG. 76, in consideration of these points, the through holes 33 are arranged in a straight line to form a line head for 150 dpi. In the line head of FIG. 76, the ink droplet flight control member 30
A through hole 33 having a diameter φ = 80 μm was formed at a pitch of 169 μm corresponding to 0 dpi, and a pair of image electrodes 31 and auxiliary electrodes 32 in a half-moon shape were arranged above and below each through hole 33. Electrode width W
Was 30 μm. Since printing at 600 dpi is impossible with this state, a pair of deflecting electrodes 35A and 35B are added to the left and right of the through hole 33 as shown in FIG. 77, so that a single through hole 33 (a pair of image electrode 31 and auxiliary electrode 32) can be used. We decided to print four dots indicated by the middle dotted line. In general, the deflection electrodes 35A and 35B are formed on another plane ahead of the plane where the image electrode 31 and the auxiliary electrode 32 are located in the direction of ink droplet travel.
A and 39B are added to make the number of electrode surfaces four, which makes it difficult to manufacture by FPC. Therefore, they were formed on the same plane for cost reduction.

In the apparatus of this embodiment, the deflection electrode 35
A, 35B (normally, one of them is grounded), the ink droplet passing through the center of the through hole 33 is moved to −42.3 μm and −21.2 μm in the left direction in FIG.
By deflecting in this order by 1.2 μm and 42.3 μm, four dots are formed. The deflection voltage required for this deflection is 2 when the shield electrodes 39A and 39B are not provided.
V and 6.2V, 6V and 18V with shield electrode
And was determined by simulation.

FIG. 78 shows that, at the start, 0 V is applied to the left deflection electrode 35A, 6 V is applied to the right deflection electrode 35B, and the left deflection electrode 35
A, 18 V to the right deflection electrode 35B, 18 V to the left deflection electrode 35A after 380 μsec,
Is a simulation result for every 100 μsec per frame when 0 V is applied to. In this simulation, 10
Since one dot is formed every 0 μsec, the deflection voltage is also switched every 100 μsec.
From the simulation of No.4, before 280μsec and 380μs
Changes in the electrode potential of the ink droplet flight control member 30 after ec are known to have no effect on the trajectory of the charged ink droplet 52, and are therefore omitted.

In FIG. 78, the right deflection electrode 35B is switched between 280 μsec and 380 μs after the injection.
+18 V was applied. The deflected printing ink droplet lands at a position of 67.4 μm (= 1.5 dots of 600 dpi) on the right side of the center. The deflection electric field formed by the pair of deflection electrodes 35A and 35B is the same electric field is applied to all holes at the same time.
Not only the ink drops for printing but also the ink drops to be collected are similarly deflected. However, as a result, there is no problem because the position corresponding to the collecting plate 63 is only shifted right and left. However, if the deflection electric field is too large compared to the image electric field, the ink droplets to be collected may flow laterally earlier than go down and do not hit the collection plate 63. This problem does not occur at least if the deflection electric field is made smaller than the control electric field (image electric field).

In the simulation shown in FIG. 78, a positive voltage having a polarity opposite to the charging polarity of the ink droplet is applied to the deflection electrode. However, even if a negative voltage having the same polarity is applied, the deflection can be performed in exactly the same manner. However, ink drops do not pass through the center,
Problems arise when passing slightly above or below the center. That is, in this case, since the ink droplet is a negatively charged ink droplet, the electric force lines shown in FIGS. 79A and 79B are reversed and shifted upward or downward. On the other hand, when a deflection voltage having a polarity opposite to the charging polarity of the ink droplet is applied, a force is applied downward when passing above the hole, and upward when passing below the hole, that is, in a direction for correcting misalignment. It is very effective.

[Embodiment 16] In the image forming apparatus according to the conventional example shown in FIG. 96 described above, it is considered that no particular measure is taken against the irregular ejection angle of ink droplets. For example, in FIG. 96, it is estimated that the garter 106 is extended slightly above the horizontal line by that amount in order to reliably collect the ink droplets to be collected that have been ejected slightly upward. In this case, it is necessary to apply a stronger deflecting electric field to pass the ink droplets for printing ejected slightly downward to pass above the garter 106. Further, in the above-mentioned document 3 in which this device is described, the charging electrode 103
Is about 8 mm, the distance between the upper and lower electrodes is about 0.6 mm, the charging voltage is about 0.2 kV, the length of the deflecting electrodes 105a and 105b is about 40 mm, the distance between the upper and lower electrodes is about 4 mm, and the deflection voltage is It is about 4 kV. The charging electrode 103 is moved in the main scanning direction (paper 10
8 at right angles to the transport direction), a high-density line head can be formed, but this is very difficult. 150 to 200 dpi (pitch between charged electrodes, 0.16
9 to 0.127 mm). As described above, in the electrostatic continuous ink jet (DIAD printer manufactured by Mead, trade name) of a line head which is actually commercialized, the nozzle pitch was 0.5 mm. In the apparatus shown in FIG. 96, the charging electrodes 103 are arranged at 150 dpi, and left and right deflecting electrodes are provided in addition to the vertical deflecting electrodes 105a and 105b so that ink droplets from one nozzle are scanned in the left and right directions. If it is deflected 4 times in the direction and 4 dots are printed, 6
Although recording can be performed at 00 dpi, it is very difficult to form a line head by closely arranging such large and high-voltage deflection electrodes. If the velocity is reduced, the momentum of the ink droplet is reduced by its square, so that it is possible to deflect with a small deflection electrode and a low deflection voltage. It is best to use electrostatic force to uniformly reduce the speed of all ink droplets. However, in the conventional apparatus of FIG. 96, this cannot be done because the amount of charge differs for each ink droplet. On the other hand, when all the ink droplets are uniformly charged as in the apparatuses of the above-described embodiments, the speed can be uniformly reduced by electrostatic force, and as a result, printing can be performed with a small deflection electrode and a low voltage. A high-density line head can be obtained by separating and printing ink droplets to be collected and ink droplets to be collected.

In the image forming apparatus of the fourteenth embodiment, as shown in FIG. 70, the charged ink droplet 52 ejected in the horizontal direction is applied to the auxiliary electrode 32 grounded to the charged electrode 22.
The ink droplet 52 is decelerated by the electrostatic force of the electric field formed between the auxiliary electrode 32 and the image electrode 31 at a speed of about 1 m / sec. Enter the area. In the image forming mode, the image electrode 31 is also 0.
V, there is no electric field in the through-hole 33, and as shown in FIG.
Land on. On the other hand, in the recovery mode, since a voltage having the same polarity as that of the ink droplet 52 is applied to the image electrode 31, a downward speed is applied in the control electric field forming region in the through hole 33, and From the outside, hits the collecting plate 63 and falls by its own weight to be collected.

Here, a simulation was performed in which the injection angle was shifted by one degree from the vertical direction in the apparatus shown in FIG. FIG. 80 shows a vertical initial velocity of the ink droplet 52 of 4.00 m / sec.
To give an initial horizontal velocity of 0.07 m / sec,
9 is a simulation result showing a flight path of an ink droplet when shifted by a degree. In this simulation, the conditions were set such that 420 V was applied to the charging electrode 22 and 0 V was applied to the image electrode 31, the auxiliary electrode 32, and the shield electrodes 39A and 39B. The time step between each diagram is 100 μsec. In this simulation, the ink droplet 52 does not enter the through-hole 33 geometrically and does not enter the upper shield electrode 39.
A, which should be A.
And landed on the counter electrode 40. However, the deviation of the landing point from the landing point when ejected vertically was -8 μm, which was unacceptable. The allowable range is 10% of the diameter of one dot of an image of 600 dpi, that is, 6 μm. As shown in FIG. 81, the reason why the ink droplet 52 entered the through-hole 33 though it was impossible geometrically was that the ink droplet flight control member 3
This is because the electrostatic force in the −X direction was obtained near 0 and the power was slightly returned to the center direction.

Next, a similar simulation was performed with the ejection angle of the ink droplet 52 shifted from the perpendicular by two degrees. In this case as well, it was possible to pass through the through-hole 33 similarly to the case of FIG. 80, but the landing point was shifted by +9 μm and was also NG. Further, a simulation was performed for a case where the injection angle deviation was 3 degrees. The result is shown in FIG. In this case, the ejected ink droplet 52 did not enter the through-hole 33 and landed on the surrounding shield electrode 39A, so that printing could not be performed. That is, in the device layout of FIG. 70, if the ejection angle of the ink droplet 52 is shifted by one degree, the deviation of the landing point exceeds the allowable range, and
If it goes wrong three times, printing itself will not be possible.

Therefore, in the apparatus of this embodiment, the deviation of the ejection angle of the ink droplet 52 is corrected by an electrostatic field, that is, a converging electric field that converges the trajectory displaced from the perpendicular to the center of the through hole 33. . Since the image electrode 31 and the auxiliary electrode 32 do not have a degree of freedom to share the role of forming the converging electric field, a converging electrode for forming the converging electric field is provided separately from these electrodes.

FIG. 83 is a schematic configuration diagram of an image forming apparatus according to this embodiment. In FIG. 83, the same components as those in the apparatus shown in FIG. 70 of the fourteenth embodiment are denoted by the same reference numerals, and their configurations and functions are also the same, and thus description thereof will be omitted. Further, effects similar to those of the device of the fourteenth embodiment are omitted. As shown in FIG. 83, a metal plate having a thickness of 0.1 mm and a hole diameter of 80 μm is provided between the charging electrode member 23 and the ink droplet flying control member 30 as the focusing electrode 64 in parallel with the members 23 and 30. It was arranged.

FIG. 84 shows a simulation result in the case where the focusing electrode 64 is grounded and the ejection angle deviation of the ink droplet 52 is set to 1 degree as in FIG. In this simulation, the conditions were set such that 440 V was applied to the charging electrode 22 and 0 V was applied to the image electrode 31, the auxiliary electrode 32, and the shield electrodes 39A and 39B. The time step between each diagram is 100 μsec. Illustration of the collecting plate is omitted. In this simulation, the ink droplet 52 passed through the through hole 33, but the landing point was shifted by -9 μm. However, the degree of allowance through the through-hole 33 was higher than in the case of FIG. 80, and it was possible to pass through the through-hole 33 up to an injection angle of 4 degrees. As described above, the printing margin was improved from 2 degrees to 4 degrees as compared with the case of FIG. 80, but the deviation of the landing point was extremely large.

FIG. 85 shows that the inner diameter of the focusing electrode is 80,12.
6 is a graph showing the relationship between the ejection deviation angle of an ink droplet and the deviation amount at a landing point in the case of 0, 160, and 200 μm.
The numbers described in FIG. 85 indicate the injection shift angles. As shown by the data when the inner diameter of the focusing electrode 64 in FIG. 84 is 80 μm, the fact that the ink droplet 52 ejected to the right is shifted to the left beyond the center of the through hole 33 on the contrary It is considered that the working converging electric field is too strong. FIG. 86 shows the electric field near the hole of the focusing electrode 64 (inner diameter: 80 μm) in this case. Here, the voltages applied to the charging electrode 22 and the focusing electrode 64 are 400 V and 0 V, respectively.
Set to. From FIG. 86, it can be seen that there is a strong horizontal electric field directed toward the center when the hole slightly deviates from the center of the hole of the focusing electrode 64.

[Embodiment 17] The device of this embodiment has basically the same configuration as that of the device of Embodiment 16 (see FIG. 83), however, in order to weaken the horizontal electric field at a point slightly distant from the center. And only the inner diameter of the focusing electrode 64 was increased from 80 μm to 120 μm while keeping the position in the Y direction. In this case, the landing position deviation at an injection deviation angle of 1 degree was -4 μm, which was within the allowable range. However, at two degrees or more, the positional deviation exceeded the allowable value. As shown in the data in FIG. 85 when the inner diameter of the focusing electrode 64 is 120 μm, there is no positional deviation up to an ejection angle deviation of 1 degree, and thereafter printing can be performed even if there is a positional deviation up to 7 degrees. This is a better result than in the case of the sixteenth embodiment (position shift occurs at one degree, and printing is possible up to four degrees). Looking at the electric field in this case, a strong horizontal electric field still exists at a point slightly away from the center (see FIG. 87).

[Embodiment 18] The device of this embodiment has basically the same configuration as that of the device of Embodiment 16 (see FIG. 83), however, in order to weaken the horizontal electric field at a point slightly distant from the center. , While keeping the position in the Y direction as it is, only the inner diameter of the focusing electrode 64 was further expanded from 120 μm to 160 μm. In this case, the inner diameter of the focusing electrode 64 in FIG.
As shown in the data for the case (1), the injection shift angle is from 1 degree to 6 degrees.
All the positional deviations were within 6 μm to the degree, and the deviation at 7 degrees was as small as −8 μm.

FIG. 88 shows a simulation result when the focusing electrode 64 having an inner diameter of 160 μm is grounded and the ejection angle deviation of the ink droplet 52 is set to 6 degrees in the apparatus of this embodiment. In this simulation, 44
0 V was applied, and the conditions were set such that 0 V was applied to the image electrode 31, the auxiliary electrode 32, and the shield electrodes 39A and 39B. The time step between each diagram is 100 μsec. Illustration of the collecting plate is omitted.

[Embodiment 19] The device of this embodiment has basically the same configuration as that of the device of Embodiment 16 (see FIG. 83). However, in order to weaken the horizontal electric field at a point slightly distant from the center. , While keeping the position in the Y direction as it is, only the inner diameter of the focusing electrode 64 was further increased from 160 μm to 200 μm. In this case, the inner diameter of the focusing electrode 64 in FIG.
As shown by the data for the case (1), the injection deviation angle is from 1 degree to 3 degrees.
All the positional deviations were within 6 μm, and the deviations at 4 and 5 degrees were as small as +8 μm and +11 μm. But,
As shown in the simulation result of FIG. 89, at the ejection deviation angle of 6 degrees, the ink droplet 52 could not return to the left and hit the ink droplet flying control member 30. FIG. 89 shows a simulation result when the focusing electrode 64 having an inner diameter of 200 μm is grounded and the ejection angle deviation of the ink droplet 52 is set to 6 degrees in the apparatus of the present embodiment. In this simulation, the conditions were set such that 440 V was applied to the charging electrode 22 and 0 V was applied to the image electrode 31, the auxiliary electrode 32, and the shield electrodes 39A and 39B. 100 time steps between each chart
μsec. Illustration of the collecting plate is omitted.

In the apparatus of the present embodiment, unlike the case of the eighteenth embodiment, the reason why the ink droplet 52 could not completely return to the left and hit the ink droplet flying control member 30 is the flight of the ink droplet having the ejection deviation angle of 6 degrees. The horizontal electric field in the path
It is supposed that, as shown by 0, it was too weak compared to the case of the eighteenth embodiment. FIGS. 90 (a) and (b) show the case where the inner diameter of the focusing electrode 64 is 160 μm and 200, respectively.
FIG. 4 is an explanatory diagram showing an electric field (distribution of lines of electric force) in the case of μm.

From the results of Embodiments 16, 17 and 18, the horizontal focusing electric field has an optimum value. If it is too strong, the electric field returns too much to hit the ink droplet flying control member 30 or the displacement in the minus direction is allowed. It can be seen that if the value exceeds the value, and if the value is too weak, it will not be able to be completely returned and will hit the ink droplet flying control member 30 or exceed the allowable value of positional deviation in the plus direction. Although it is difficult to show the optimum value by a mathematical expression, basically, the maximum amount of the horizontal displacement from the center is calculated from the
A convergent horizontal electric field may be used to provide a reverse velocity that just cancels while flying to zero.

In the embodiments 16, 17, 18 and 19, the focusing electrodes 64 are all grounded. However, in order to form a necessary focusing electric field, an appropriate potential is applied without grounding. You may. However, in this case, when a potential difference occurs between the shield electrode 39A and the focusing electrode 64A, an electric field is generated between the focusing electrode 64 and the shield electrode 39A to diffuse or converge the charged ink droplet 52 from the center.
Optimal design becomes complicated. Of course, it is theoretically possible to control using this, but it is not practical. It is safer to ground all the parts except the charging electrode 22 and the image electrode 31, and there is no influence of the displacement of the electrodes.

In each of the above embodiments, the case where an image is directly formed on paper as an image forming object has been described. However, the present invention is directed to a case where an image is formed on an intermediate transfer member having a good surface property as an image forming object. Is formed and then transferred to an image forming apparatus configured to transfer it to paper.

[0193]

According to the first to fourth aspects of the present invention, the deflection of the charged ink droplet is controlled inside the through hole surrounded by the image electrodes and hardly affected by the electrostatic influence from the surroundings. Since the control electric field is formed, the crosstalk in the control electric field for controlling the charged ink droplets discharged from each nozzle is reduced even when the through holes are arranged close to each other. Therefore, compared with the case where a conventional flat-shaped deflection electrode is used as the ink droplet flight control means, it is easy to increase the number of nozzles with high density,
In addition, there is an effect that the displacement of the landing position of the ink droplet due to the crosstalk can be reduced.

In particular, according to the second aspect of the present invention, the inside of the apparatus is not contaminated by charged ink droplets flying in a direction different from the direction toward the image forming object, and the ink droplets can be reused. Has the effect of becoming

In particular, according to the invention of claim 3, there is an effect that a charged ink droplet flying toward the through hole can be deflected with a smaller control voltage.

In particular, according to the invention of claim 4, there is an effect that a plurality of dots of an image can be formed by ink droplets passing through the control electric field forming region formed in one through hole.

According to the fifth to 54th aspects of the present invention, the control electric field for controlling the deflection of the charged ink droplet is provided inside the through hole surrounded by the image electrodes and hardly affected by the electrostatic influence from the surroundings. Is formed, the crosstalk in the control electric field for controlling the charged ink droplets discharged from each nozzle is reduced even when the through holes are arranged close to each other. Therefore, compared with the case where a conventional flat-shaped deflection electrode is used as the ink droplet flight control means, it is easy to increase the number of nozzles with high density,
In addition, there is an effect that the displacement of the landing position of the ink droplet due to the crosstalk can be reduced.

In particular, according to the present invention, the inside of the apparatus is not contaminated by charged ink droplets flying in a direction different from the direction toward the image forming object. The effect is that it can be used.

In particular, according to the invention of claims 7, 10 to 20 and 22 to 30, the layout of the collection container for collecting the charged ink droplets flying in a direction different from the direction toward the image forming object is described. This has the effect of increasing the degree of freedom.

According to the eighth, tenth to nineteenth, and twenty-second to thirty-second aspects of the present invention, a member is provided for guiding a charged ink droplet flying in a direction different from the direction toward the image forming object to the collection container. There is an effect that there is no need.

In particular, claims 9 to 19 and 21
According to the twenty-fifth to twenty-fifth aspects, since the ink container is also used as the collection container, there is an effect that the device configuration is simplified.

In particular, according to the tenth to fourteenth aspects of the invention, there is an effect that the collection time of each ink droplet is shortened.

According to the eleventh aspect of the present invention, since the charged ink droplet toward the collection container is accelerated by an air current, there is an effect that the configuration of the accelerating means is simplified.

According to the twelfth to fourteenth aspects of the present invention, since the charged ink droplets heading toward the collection container are accelerated by an electric field which can be easily controlled, the ink droplets can be collected stably. This has the effect.

In particular, according to the thirteenth aspect of the present invention, a ring-shaped plane electrode is used as each of a pair of recovery accelerating electrodes provided side by side along a flight path of the charged ink droplet toward the recovery container. There is an effect that can be.

Further, in particular, according to the fourteenth aspect of the present invention, a pair of deceleration electrodes for forming an electric field for decelerating a charged ink droplet from the ink container toward the through hole is used as the recovery accelerating electrode. Since it is possible, there is an effect that the device configuration is simplified.

In particular, according to the invention of claims 15 to 19, the ink droplets can be ejected from the nozzle holes such that a plurality of charged ink droplets are simultaneously present in the flight path toward the through hole. There is an effect that the speed of image formation can be increased.

In particular, according to the nineteenth aspect of the present invention, charged ink droplets discharged from an ink container can be initially discharged without employing a configuration in which the image electrodes are divided to provide a potential difference between the electrodes. This makes it possible to fly while shifting in a direction inclined from the direction, so that the flight path toward the through-hole and the recovery flight path can be made different.

According to the twentieth aspect of the present invention, in particular, the ink droplets received by the ink droplet collecting member do not remain attached to the surface of the member. There is an effect that the flow is collected smoothly in the collection container.

According to the twenty-first aspect of the present invention, there is an effect that ink droplets are not ejected from the recovery port of the ink container.

According to the present invention, the flying of the charged ink droplet from the ink container toward the through hole and the reverse flying of the charged ink droplet toward the collection port of the collection container are not blocked by the auxiliary electrode. . Moreover, by using one metal plate for the auxiliary electrode, there is an effect that an auxiliary electrode that is inexpensive, accurate, and excellent in mechanical strength can be manufactured.

According to the present invention, the charged ink droplets to be collected in the collection container can be collected at a position away from the nozzle hole of the ink container. This has the effect of making it easier.

In particular, according to the twenty-sixth to thirty-seventh aspects of the present invention, even if the flying speed of the charged ink droplet changes due to a change in the particle diameter of the charged ink droplet adhered to the image forming object, the amount of the ink droplet deposited on the image forming object changes. Since the point does not change, stable image formation can be performed. In addition, since the charged ink droplet heading toward the collection container is not blocked by the ink droplet flight control member, there is an effect that the ink droplet can be collected stably.

According to the twenty-seventh aspect of the present invention, the predetermined voltage is applied to the first image electrode, the second image electrode, and the third image electrode. There is an effect that the charged ink droplet can be deflected in a direction along the surface of the ink droplet flight control member.

Further, in particular, according to the inventions of claims 28 to 30, there is an effect that the ink droplets heading toward the collection container can be accelerated by the pair of collection electrodes and can be collected more quickly.

In particular, according to the twenty-ninth aspect of the present invention, there is an effect that the manufacturing cost of the recovery electrode and the image electrode can be reduced.

According to the invention, the electric field formed by the collecting electrode does not act on the charged ink droplet passing through the control electric field forming region formed by the image electrode toward the image forming object. Therefore, there is an effect that stable image formation can be performed without disturbing the flight of the charged ink droplet toward the image forming object.

Further, in particular, according to the inventions of claims 31 to 33, it is possible to reduce the applied voltage (control voltage) to the image electrode required to deflect the charged ink droplet by a predetermined distance. Moreover, even when the speed of the charged ink droplets discharged from the ink container is high, there is an effect that the ink droplets can be stably deflected according to the image information.

In particular, according to the invention of claim 32, it is possible to improve the relative positional accuracy between the auxiliary electrode and the image electrode and to reduce the cost of manufacturing both electrodes. effective.

In particular, according to the inventions of claims 34 to 40, the deceleration of the charged ink droplets facilitates the deflection of the ink droplets, so that the application to the image electrode necessary for deflecting by a predetermined distance is performed. There is an effect that the voltage (control voltage) can be reduced.

In particular, according to the thirty-fifth aspect of the invention, there is an effect that even an ink droplet having a small charge amount and a large particle diameter, which is not easily decelerated by air resistance or electrostatic force, can be easily decelerated.

According to the present invention, the charged ink droplets are decelerated by an electric field which can be easily controlled, so that the ink droplets can be decelerated more accurately and stably. There is.

According to the present invention, a planar electrode can be used as each electrode of the pair of ring-shaped deceleration electrodes as an electrode for decelerating the charged ink droplet toward the through hole. effective.

In particular, according to the thirty-eighth to thirty-ninth aspects of the present invention, since the other of the pair of deceleration electrodes is also used as the deceleration electrode near the ink droplet nozzle hole of the ink container, the apparatus configuration is reduced. This has the effect of being simple.

In particular, according to the invention of claim 41, the applied voltage (control voltage) to the image electrode required to deflect the charged ink droplet flying toward the through hole by a predetermined distance is reduced. be able to. Moreover, even when the speed of the charged ink droplets discharged from the ink container is high, there is an effect that the ink droplets can be stably deflected according to the image information.

In particular, according to the invention of claim 42, the speed of image formation can be increased because the charged ink droplets passing through the control electric field forming region by the image electrode and moving toward the image forming object are accelerated. effective.

In particular, according to the inventions of claims 43 to 46, the charged ink droplets passing through the control electric field forming region formed by the image electrodes toward the image forming object are deflected by the deflecting electrodes. There is an effect that a plurality of dots of an image can be formed by ink droplets passing through the formed control electric field forming region.

In particular, according to the invention of claim 44, there is an effect that the influence of the deflection electric field by the deflection electrode on the selective deflection of the charged ink droplet by the control electric field by the image electrode is reduced.

In particular, according to the forty-fifth aspect, there is an effect that the control of the applied voltage for forming the plurality of dots is facilitated.

In particular, according to the forty-sixth aspect, the relative positional accuracy between the deflection electrode and the image electrode can be improved, and the cost of manufacturing both electrodes can be reduced. effective.

In particular, according to the invention of claims 47 to 49, immediately after the previously flying charged ink droplet has passed through the control electric field formation region by the image electrode, or the subsequent charged ink droplet is formed by the control electric field formation. Since the voltage to be applied to the image electrode can be switched just before entering the area, the effect of shortening the discharge interval of the charged ink droplet and increasing the speed of image formation can be obtained.

In particular, according to the forty-eighth aspect of the present invention, even if a charged ink droplet adheres to an image electrode and the image electrode and the shield electrode are electrically connected, an excess current flows. Therefore, there is an effect that the risk of breaking an electric circuit for applying to each electrode is reduced.

In particular, according to the invention of claim 49, it is possible to improve the relative positional accuracy between the shield electrode and the image electrode and to reduce the cost of manufacturing both electrodes. effective.

In particular, according to the inventions of claims 50 to 53, the charged ink droplets directed from the nozzle holes of the ink container to the through holes are converged in the through holes by the converging electrodes, so that the ink droplets are ejected from the ink containers. Even when the ejection angle of the ink droplet varies, there is an effect that the ink droplet can be reliably incident on the through-hole and the selective deflection of the ink droplet according to the image information can be reliably performed. .

In particular, according to the invention of the fifty-first aspect, there is an effect that the adjustment range of the variation in the ejection direction of the ink droplet is widened.

In particular, according to the invention of claim 52, an unnecessary electric field is prevented from being formed between the focusing electrode and a shield electrode provided on the focusing electrode side of the image electrode, and the through-hole is prevented. This has the effect that the flying of the charged ink droplet toward the head becomes stable.

Further, in particular, according to the invention of claim 53, the charged ink droplets discharged from the ink container reach a predetermined position on the image forming object and adhere thereto, thereby enabling stable image formation. effective.

In particular, according to the invention of claim 54, at least one of the above-mentioned electrodes is connected to an inexpensive flexible printed circuit (FP) in which electrode pattern alignment is easy.
C) Since it can be formed on a member, there is an effect that the positional accuracy of each electrode is further improved and the cost of manufacturing can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2A is a cross-sectional view of an ink droplet flight control member 30 used in the image forming apparatus. (B) is a longitudinal sectional view of the ink droplet flight control member 30.

FIG. 3 is a graph showing a relationship between a particle diameter of an ink droplet and a highest point in the image forming apparatus.

FIGS. 4A to 4O are explanatory diagrams showing simulation results of reversal movement of charged ink droplets in the image forming apparatus.

FIGS. 5A to 5O are explanatory diagrams showing simulation results of a flight path of a charged ink droplet adhering to paper in the image forming apparatus.

FIG. 6 is a schematic configuration diagram of an image forming apparatus according to a second embodiment.

FIG. 7 is an explanatory diagram showing the arrangement of through holes and image electrodes in an ink droplet flight control member used in the image forming apparatus.

FIG. 8 is a schematic configuration diagram of an image forming apparatus according to a third embodiment.

FIGS. 9A to 9O are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 10A to 10O are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus. FIGS.

FIGS. 11A to 11O are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode when a voltage applied to a counter electrode of the image forming apparatus is set to 0V.

FIG. 12 is a schematic configuration diagram of an image forming apparatus according to a fourth embodiment.

FIGS. 13A to 13O are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 14A to 14O are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIG. 15 is a schematic configuration diagram of an image forming apparatus according to a fifth embodiment.

FIGS. 16 (a) to (o) are explanatory views showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 17 (a) to (o) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode when the light beam is deflected in a direction opposite to that of FIG. 17;

FIGS. 18A to 18O are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of an image forming apparatus according to a comparative example of the sixth embodiment.

FIGS. 19 (a) to (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the recovery mode when a voltage (+50 V / −50 V) is applied to the auxiliary electrode pair of the image forming apparatus. .

FIG. 20 is a schematic configuration diagram of an image forming apparatus according to a sixth embodiment.

FIG. 21 is a schematic configuration diagram of an image forming apparatus according to a seventh embodiment.

FIGS. 22 (a) to (o) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in a collection mode of the image forming apparatus.

FIGS. 23A to 23O are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 24 (a) to (o) are explanatory diagrams showing simulation results of the flight paths of the charged ink droplets in the collection mode when a deflection electrode is added to the image forming apparatus of FIG. 22.

FIGS. 25A to 25O are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 26A to 26O are diagrams illustrating simulation results of flight paths of charged ink droplets in an image forming mode when a voltage (+30 V / −30 V) is applied to a deflection electrode of the image forming apparatus. FIG.

FIGS. 27 (a) to (o) are explanatory diagrams showing simulation results of flight paths of charged ink droplets in an image forming mode when voltages of opposite polarities (−30 V / + 30 V) are applied to the same deflection electrode. .

FIG. 28 is a graph showing a flying speed change of a charged ink droplet in an image forming apparatus according to a comparative example of the eighth embodiment.

FIG. 29 is an explanatory diagram showing a line of electric force distribution between a charging electrode and an ink droplet flying control member of the image forming apparatus.

FIG. 30 is an explanatory diagram showing a line of electric force distribution between a charging electrode and an ink droplet flight control member of the image forming apparatus according to the eighth embodiment.

FIG. 31 is a graph showing a change in flying speed of a charged ink droplet in the image forming apparatus.

FIGS. 32 (a) to (o) are explanatory views showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIGS. 33 (a) to (o) are explanatory views showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 34 (a) to (o) are explanatory views showing simulation results of the flight path of the charged ink droplet in the collection mode of the image forming apparatus according to the comparative example of the ninth embodiment.

FIG. 35 is an explanatory diagram showing a distribution of lines of electric force between a charging electrode and an ink droplet flying control member of the image forming apparatus.

FIG. 36 is an explanatory diagram illustrating a distribution of lines of electric force between a charging electrode and an ink droplet flying control member of the image forming apparatus according to the ninth embodiment.

FIGS. 37 (a) to (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIG. 38 is an explanatory diagram showing a distribution of lines of electric force between a charging electrode and an ink droplet flying control member of the image forming apparatus according to the tenth embodiment.

FIGS. 39 (a) to (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIG. 40 shows a vertical velocity Vy when entering an electric fieldless area of the image forming apparatus, and a distance Dx from an injection hole to a landing point.
The graph which shows the relationship with.

FIG. 41 is an explanatory diagram of an electrode arrangement in a simulation performed as a comparative example of the eleventh embodiment.

FIGS. 42 (a) to (o) are explanatory views showing simulation results of the flight paths of the charged ink droplets in the collection mode of the image forming apparatus according to the comparative example.

FIGS. 43 (a) to (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 44A to 44R are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the collection mode when the ink droplet diameter in the image forming apparatus has changed from 30 μm to 34 μm.

FIGS. 45 (a) to (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the collection mode when the ink droplet diameter in the image forming apparatus has changed from 30 μm to 26 μm.

FIGS. 46 (a) to (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the image forming mode when the ink droplet diameter in the image forming apparatus is changed from 30 μm to 34 μm. .

FIGS. 47 (a) to (o) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode when the ink droplet diameter in the image forming apparatus is changed from 30 μm to 26 μm. .

FIG. 48 is a schematic configuration diagram of an image forming apparatus according to an eleventh embodiment.

FIG. 49 is an explanatory diagram of an electrode arrangement in a simulation of the image forming apparatus.

FIGS. 50 (a) to (o) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in a collection mode of the image forming apparatus.

FIGS. 51 (a) to 51 (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 52 (a) to 52 (o) are explanatory views showing simulation results of the flight path of the charged ink droplet in the collection mode when the particle size of the ink droplet of the image forming apparatus is 26 μm.

FIG. 53 is an explanatory diagram showing electric line of force distribution between first and second ink droplet flight control members of the image forming apparatus.

FIGS. 54 (a) to (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the collection mode when the particle size of the ink droplet of the image forming apparatus is 34 μm.

FIGS. 55 (a) to (t) are explanatory views showing simulation results of the flight path of the charged ink droplet in the image forming mode when the particle diameter of the ink droplet of the image forming apparatus is 26 μm.

FIGS. 56 (a) to 56 (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the image forming mode when the particle diameter of the ink droplet of the image forming apparatus is 34 μm.

FIG. 57 is a schematic configuration diagram of an image forming apparatus according to a twelfth embodiment.

FIG. 58 is an explanatory diagram of an electrode arrangement in a simulation of the image forming apparatus.

FIGS. 59 (a) to 59 (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 60 (a) to (o) are explanatory diagrams showing simulation results of the flight path of the charged ink droplet in the collection mode of the image forming apparatus.

FIGS. 61 (a) to (o) are explanatory views showing simulation results of a flight path of a charged ink droplet in a collection mode of an image forming apparatus according to a modification of the twelfth embodiment. FIGS.

FIGS. 62 (a) to 62 (o) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of the image forming apparatus according to the modification.

FIGS. 63 (a) to 63 (o) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of an image forming apparatus according to another modification.

FIG. 64 is a schematic configuration diagram of an image forming apparatus according to a thirteenth embodiment.

FIG. 65 is an explanatory diagram of an electrode arrangement in a simulation of the image forming apparatus.

FIGS. 66 (a) to (l) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 67 (a) to 67 (l) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIG. 68 is a graph showing a relationship between an image signal (control voltage) switching time and a landing point shift amount in the image forming apparatus.

FIG. 69 is a graph showing a relationship between an image signal (control voltage) switching time and a landing point shift amount in the image forming apparatus.

FIG. 70 is a schematic configuration diagram of an image forming apparatus according to a fourteenth embodiment.

FIGS. 71 (a) to (l) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in a collection mode of the image forming apparatus.

FIGS. 72 (a) to (l) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIG. 73 is an explanatory diagram showing an electric line of force distribution above an ink droplet flying control member when −24 V is applied to an image electrode of the image forming apparatus.

74 is an explanatory diagram showing a distribution of electric lines of force inside a through hole of the ink droplet flight control member. FIG.

FIG. 75 is an explanatory diagram showing a line of electric force distribution below the ink droplet flight control member 30.

FIG. 76 is an explanatory view showing electrode arrangement in an ink droplet flight control member of the image forming apparatus according to the fifteenth embodiment.

FIG. 77 is an explanatory view showing another electrode arrangement in the ink droplet flight control member.

FIGS. 78 (a) to (l) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIGS. 79A and 79B are explanatory diagrams showing distributions of electric force lines inside the through holes of the ink droplet flight control member of the image forming apparatus. FIGS.

FIGS. 80 (a) to (l) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in an image forming mode of an image forming apparatus according to a comparative example of the sixteenth embodiment.

FIG. 81 is an explanatory diagram showing a line of electric force distribution between a charging electrode and an ink droplet flying control member in the image forming mode.

FIGS. 82 (a) to (d) are explanatory views showing simulation results of a flying path of a charged ink droplet in an image forming mode of an image forming apparatus according to another comparative example of the sixteenth embodiment.

FIG. 83 is a schematic configuration diagram of an image forming apparatus according to a sixteenth embodiment.

84 (a) to (l) are explanatory diagrams showing simulation results of a flying path of a charged ink droplet in an image forming mode of the image forming apparatus.

FIG. 85 is a graph showing a relationship between an ejection deviation angle of an ink droplet and a landing position deviation amount of the image forming apparatus.

FIG. 86 is an explanatory view showing a line of electric force distribution between a charging electrode and a focusing electrode of the image forming apparatus.

FIG. 87 is an explanatory diagram showing a line of electric force distribution between the charging electrode and the focusing electrode of the image forming apparatus according to the seventeenth embodiment.

FIGS. 88 (a) to (l) are explanatory diagrams showing simulation results of a flight path of a charged ink droplet in the image forming apparatus according to the eighteenth embodiment.

FIGS. 89 (a) to 89 (h) are explanatory diagrams showing simulation results of flying paths of charged ink droplets in the image forming apparatus according to the nineteenth embodiment. FIGS.

FIGS. 90A and 90B are explanatory diagrams showing distributions of electric force lines when the inner diameter of the focusing electrode of the image forming apparatus is 160 μm and 200 μm, respectively.

FIGS. 91A and 91B are schematic configuration diagrams of an image forming apparatus according to a conventional example.

FIG. 92 is a schematic configuration diagram of an image forming apparatus according to another conventional example.

FIG. 93 is a schematic configuration diagram of an image forming apparatus according to still another conventional example.

FIG. 94 is an explanatory diagram illustrating the principle of charging and deflection in the image forming apparatus.

FIG. 95 is a schematic configuration diagram of an image forming apparatus according to still another conventional example.

FIG. 96 is a schematic configuration diagram of an image forming apparatus according to still another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ink container 11 Base electrode 12 Nozzle hole 13 Collection hole 20, 22 Charge electrode 20A, 20B Hole 21 Hole 23 Charge electrode member 30, 36 Ink droplet flight control member 31 Image electrode 31A First image electrode 31B Second image electrode 31C Third image electrode 32 Auxiliary electrode 33 Through hole 34 Resin film 35A, 35B Deflection electrode 37A, 37B Recovery electrode 38 Shield electrode 39A, 39B Shield electrode 40 Counter electrode 50 Ink 51 Ink column 52 Charged ink droplet 52A Ink to be collected Drops 52B Ink drops for printing 53 Paper 60A, 60B Deceleration electrode member 61A, 61B Deceleration electrode 62 Auxiliary electrode 62A First auxiliary electrode 62B Second auxiliary electrode 62C Third auxiliary electrode 62D Inlet hole 62E Exit hole 63 Recovery plate 64 focusing electrode

 ──────────────────────────────────────────────────続 き Continuation of front page (71) Applicant 597063831 Owneds Brygga 13 421 57 Vestro Fround a Sweden F-term (reference) 2C057 AF30 AH07 AM03 AM22 BD05 BD12 EC04

Claims (54)

[Claims] An image forming apparatus configured to selectively deflect a charged ink droplet flying in one direction in accordance with image information so that the charged ink droplet is selectively attached to an image forming object; In an image forming method for forming an image on an object, the charged ink droplet flies toward a through hole surrounded by an image electrode to which a control voltage corresponding to image information is applied, and attempts to pass through the through hole. An image forming method, wherein the charged ink droplet is selectively deflected. 2. An image forming method according to claim 1, wherein said charged ink droplets flying in a direction different from a direction toward said image forming object are collected. 3. The image forming method according to claim 1, wherein the charged ink droplet flying toward the through hole is decelerated. 4. The image forming method according to claim 1, wherein a charged ink droplet passing through a control electric field forming region formed by said image electrode and flying toward said image forming object is deflected based on image information. An image forming method, comprising: changing a position where the charged ink droplet is attached on an object to be formed. 5. An apparatus according to claim 1, further comprising: an ink droplet ejection means for ejecting the charged ink droplet from a nozzle hole of the ink container; and an ink droplet flight control means for selectively deflecting the charged ink droplet in accordance with image information. In an image forming apparatus for forming an image on an image forming object by selectively adhering droplets on the image forming object, a plurality of through holes surrounded by image electrodes are formed as the ink droplet flying control means. An image characterized by comprising an ink droplet flight control member, and control voltage applying means for applying a control voltage for selectively deflecting the charged ink droplet according to image information to the image electrode. Forming equipment. 6. An image forming apparatus according to claim 5, further comprising an ink droplet collecting means for collecting charged ink droplets flying in a direction different from a direction toward said image forming object. . 7. An image forming apparatus according to claim 6, wherein said ink droplet collecting means comprises: a collecting container for storing the collected ink droplets; and a charged ink droplet flying in a direction different from the direction toward the image forming object. And an ink droplet collecting member for receiving the ink droplets and guiding the collected ink to the collection container. 8. The image forming apparatus according to claim 6, wherein said ink droplet collecting means is a collecting container having a collecting port for directly receiving charged ink droplets flying in a direction different from a direction toward said image forming object. An image forming apparatus comprising: 9. An image forming apparatus according to claim 6, wherein said ink droplet collecting means is constituted by using said ink container also serving as said collecting container, and said ink droplet collecting means flies in a direction different from a direction toward said image forming object. The flying direction of the charged ink droplet is set such that the ink droplet directly enters the collection port of the ink container. 10. An image forming apparatus according to claim 7, 8 or 9, further comprising an accelerating means for accelerating the charged ink droplet toward said collection container. 11. An image forming apparatus according to claim 10, further comprising an airflow generating means for generating an airflow in a direction for accelerating the charged ink droplets directed to said collection container as said acceleration means. . 12. An image forming apparatus according to claim 10, wherein said accelerating means includes electric field forming means for forming an electric field for accelerating charged ink droplets directed to said collection container. . 13. An image forming apparatus according to claim 12, wherein said electric field forming means comprises a pair of recovery accelerating electrodes provided side by side along a flight path of the charged ink droplet toward said collection container, and accelerating said charged ink droplet. An image forming apparatus comprising: a power source for applying a voltage for forming an electric field in a direction between the pair of recovery accelerating electrodes. 14. A pair of deceleration electrodes for forming an electric field for decelerating the ink droplets along a flight path of the charged ink droplets from the ink container toward the through hole,
13. The image forming apparatus according to claim 12, wherein a flying direction of the charged ink droplet toward the through-hole and a collecting flight direction of the charged ink droplet toward the collection container are opposite to each other. An image forming apparatus, wherein the image forming apparatus is also used. 15. The image forming apparatus according to claim 7, 8 or 9, wherein a trajectory of the charged ink droplets collected in the collection container from the ink container to the through hole and a collection trajectory to the collection container. An image forming apparatus characterized by being different. 16. An image forming apparatus according to claim 15, wherein said image electrode is divided into a plurality of electrodes in a plane direction intersecting a flight direction from said ink container, and different voltages are applied to each electrode. Thus, the image forming apparatus is characterized in that the charged ink droplet ejected from the ink container flies while shifting in a direction inclined from the initial ejection direction. 17. The image forming apparatus according to claim 15, wherein an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode. The auxiliary electrode is divided into a plurality of electrodes in a plane direction intersecting the flight direction from the ink container, and a different voltage is applied to each electrode, whereby charged ink droplets discharged from the ink container are applied. An image forming apparatus which flies while shifting in a direction inclined from an initial ejection direction. 18. An image forming apparatus according to claim 15, wherein said ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of said ink container. As the charging electrode, one divided into a plurality of electrodes in a plane direction intersecting with the flight direction from the ink container is used, and a different voltage is applied to each electrode, so that the charged ink droplets ejected from the ink container are initialized. An image forming apparatus, which flies while shifting in a direction inclined from a discharge direction. 19. An image forming apparatus according to claim 15, wherein an inner peripheral surface of said image electrode has an axially symmetric shape with respect to a center axis of said through hole. An image forming apparatus, wherein the light is incident off the axis. 20. The image forming apparatus according to claim 7, wherein a surface of said ink droplet collecting member with which the charged ink droplet contacts is subjected to a water-repellent treatment. 21. The image forming apparatus according to claim 9, wherein the recovery port of the ink container is formed at a position away from the nozzle hole of the ink container to such an extent that the ink droplet is not ejected from the recovery port. Image forming apparatus. 22. An auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode, and the recovery container is sandwiched between the auxiliary electrode. 10. The image forming apparatus according to claim 7, wherein the image electrode is disposed on a side opposite to the image electrode, wherein a charged ink droplet flying from the ink container toward the through hole passes as the auxiliary electrode. Holes and
An image forming apparatus using a single metal plate having a hole through which a charged ink droplet that flies backward toward a collection port of the collection container passes. 23. An auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to the nozzle hole of the ink container than the image electrode, and the recovery container is sandwiched between the auxiliary electrode and the auxiliary electrode. 10. The image forming apparatus according to claim 7, which is disposed on a side opposite to the image electrode, wherein the electric field accelerates a charged ink droplet to be collected in the collection container in a direction of a nozzle hole of the ink container. An image forming apparatus wherein the shape, arrangement, and applied voltage of the auxiliary electrode are set so that no image is formed. 24. An auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to the nozzle hole of the ink container than the image electrode, and the recovery container is sandwiched between the auxiliary electrode. 10. The image forming apparatus according to claim 7, wherein the image electrode is disposed on a side opposite to the image electrode, wherein a speed of the charged ink droplet to be collected in the collection container in a direction toward a nozzle hole of the ink container is reduced. An image forming apparatus, wherein the shape, arrangement, and applied voltage of the auxiliary electrode are set so as to form a decelerating electric field. 25. An auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode, and the recovery container is sandwiched between the auxiliary electrode. 10. The image forming apparatus according to claim 7, wherein the charged ink droplets to be collected in the collection container are in a direction opposite to a direction of a nozzle hole of the ink container. An image forming apparatus wherein the shape, arrangement, and applied voltage of the auxiliary electrode are set so that an electric field that accelerates is formed. 26. The image forming apparatus according to claim 7, wherein, of the charged ink droplets discharged from the ink container, the charged ink droplets to be attached to the image forming object are caused to fly straight and fly. An image forming apparatus, comprising: the image electrode provided to deflect a charged ink droplet collected in a collection container in a direction along a surface of the ink droplet flight control member. 27. The image forming apparatus according to claim 26, wherein said image electrode includes a ring-shaped first image electrode disposed so as to surround a through hole through which a charged ink droplet passes. A second image electrode and a third image electrode are provided facing each other so as to sandwich a through hole through which the charged ink droplet passes on the upstream side in the ink droplet flight direction, and the charged ink droplet collected in the collection container is provided. Is flying, a voltage having the same polarity as the charged polarity of the charged ink droplet is applied to the first image electrode and the second image electrode,
An image forming apparatus, wherein a voltage having a polarity opposite to the charging polarity of the charged ink droplet is applied to the image electrode. 28. The image forming apparatus according to claim 26, wherein a pair of collections for forming an electric field for deflecting the charged ink droplets collected in the collection container in a direction along a surface of the ink droplet flight control member. An image forming apparatus provided with electrodes. 29. The image forming apparatus according to claim 28, wherein said recovery electrode is formed on the same member together with said image electrode. 30. An image forming apparatus according to claim 28, wherein a shield electrode is provided between the recovery electrode and a flight path of the charged ink droplet passing through the control electric field forming region by the image electrode toward the image forming object. An image forming apparatus, comprising: 31. The image forming apparatus according to claim 5, wherein a voltage for forming an electric field for assisting the deflection of the charged ink droplet is applied to the auxiliary electrode arranged to surround the through hole. An image forming apparatus comprising a power supply. 32. An image forming apparatus according to claim 31, wherein said auxiliary electrodes are formed on the same member together with said image electrodes. 33. The image forming apparatus according to claim 31, wherein the auxiliary electrode is provided at a position closer to a nozzle hole of the ink container than the image electrode.
In the image forming apparatus, an electric field for accelerating the ink droplet is not formed in a flight path until the charged ink droplet discharged from the ink container reaches a control electric field forming region formed by the image electrode. An image forming apparatus wherein the shape, arrangement, and applied voltage of the auxiliary electrode are set as described above. 34. The image forming apparatus according to claim 5, further comprising an ink droplet reducing means for reducing a charged ink droplet flying from said ink container toward said through hole. 35. An image forming apparatus according to claim 34, wherein said ink droplet decelerating means is provided with airflow generating means for generating an airflow in a direction to decelerate charged ink droplets directed to said through holes. Forming equipment. 36. An image forming apparatus according to claim 34, wherein said ink droplet decelerating means is provided with an electric field forming means for forming an electric field for decelerating the charged ink droplet toward said through hole. Forming equipment. 37. The image forming apparatus according to claim 36, wherein said electric field forming means is provided with a pair of deceleration electrodes arranged along a flight path of the charged ink droplet toward said through hole, and decelerates said charged ink droplet. An image forming apparatus comprising: a power source for applying a voltage for forming a direction electric field between the pair of deceleration electrodes. 38. The image forming apparatus according to claim 37, wherein said ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of said ink container. An image forming apparatus characterized in that the charging electrode is also used as a deceleration electrode of the pair of deceleration electrodes which is closer to a nozzle hole of the ink container. 39. The image forming apparatus according to claim 37, wherein an auxiliary electrode for forming an electric field for assisting the deflection of the charged ink droplet is provided at a position closer to a nozzle hole of the ink container than the image electrode. An image forming apparatus, wherein the auxiliary electrode is also used as a deceleration electrode closer to the image electrode among the pair of deceleration electrodes. 40. The image forming apparatus according to claim 37, wherein the image electrode is also used as a deceleration electrode of the pair of deceleration electrodes which is closer to the image forming object. 41. The image forming apparatus according to claim 5, wherein the particle diameter of the charged ink droplet is set to such an extent that the charged ink droplet flying toward the through hole is decelerated by air resistance. Forming equipment. 42. The image forming apparatus according to claim 5, wherein a counter electrode disposed at a position facing the image forming object from a side opposite to the image electrode is opposite to a charging polarity of the charging ink droplet. An image forming apparatus, comprising: a power supply for applying a polarity voltage to the counter electrode. 43. The image forming apparatus according to claim 5, wherein the flying path of the ink droplet is interposed at a position where the flying of the charged ink droplet is not hindered between the image electrode and the image forming object. An image forming apparatus, comprising: a pair of deflecting electrodes; and a power supply for applying a voltage to the deflecting electrodes to apply a voltage for forming an electric field for deflecting the ink droplets attached to the image forming object. 44. The image forming apparatus according to claim 43, wherein the intensity of the control electric field by said image electrode is made stronger than the intensity of the deflection electric field by said deflection electrode. 45. An image forming apparatus according to claim 43, wherein one of said pair of deflecting electrodes is grounded and a voltage having a polarity opposite to that of said charged ink droplet is applied to the other. apparatus. 46. An image forming apparatus according to claim 43, wherein said deflecting electrodes are formed on the same member together with said image electrodes. 47. The image forming apparatus according to claim 5, wherein a shield electrode is provided on the ink container side and the image forming object side of the image electrode. 48. The image forming apparatus according to claim 47, wherein the shield electrode is grounded, and a pair of image electrodes arranged so as to face each other with the through hole interposed therebetween is used as the image electrode. An image forming apparatus, wherein one of a pair of image electrodes is grounded, and a voltage having the same polarity as the charging polarity of the charged ink droplet is applied to the other. 49. The image forming apparatus according to claim 47, wherein said shield electrode and said image electrode are formed on the same member. 50. The image forming apparatus according to claim 5, wherein an electric field for converging the charged ink droplet in the through hole is formed so as to surround a flight path of the charged ink droplet from the ink container toward the through hole. Forming apparatus provided with a focusing electrode for the image forming apparatus. 51. The image forming apparatus according to claim 50, wherein an inner diameter of said focusing electrode is larger than an inner diameter of said image electrode. 52. An image forming apparatus according to claim 50, wherein a grounded shield electrode is provided on said focusing electrode side of said image electrode, wherein said focusing electrode is grounded. 53. The image forming apparatus according to claim 50, wherein said ink droplet discharging means is constituted by using a charging electrode arranged so as to sandwich an ink droplet to be discharged from a nozzle hole of said ink container. A potential difference is formed between the charging electrode and the focusing electrode so that the charged ink droplet discharged from the nozzle hole of the ink container reaches and adheres to a predetermined position on the image forming object. Image forming device. 54. The image forming apparatus according to claim 5, wherein at least one of said electrodes is formed on a flexible printed circuit (FPC) member.