JPH10258511A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always jet a definite amt. of ink and to form a high quality image with a uniform dot diameter by changing the electric field between a recording electrode and a recording medium in accordance with the recording pattern of the image. SOLUTION: When an electric potential V1 or V2 is applied on a recording electrode 32 and an electric potential V0 is applied on an opposing electrode 6 and a relation among these electric potentials is V0<V1<V2, an equipotential line a and an electric field b are formed between both electrodes 6 and 32. In addition, when the electric potential V2 is applied on the recording electrode 32, ink drops 42 are released from the recording electrode 32 and the released ink drops 42 fly toward the opposing electrode 6 and are transferred on a paper. In this instance, by controlling the pulse width of a recording pulse applying image data transferred from an outside image instrument on the recording electrode 32 of an aimed picture element in accordance with a recording pattern before the aimed picture element, a definite amt. of ink can be always jetted and transferred on a paper regardless of the recording patterns of the picture elements before the aimed picture element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supplying ink to a recording electrode by dispersing charged colorant particles (toner particles) in an insulating liquid (liquid carrier). The present invention relates to an ink jet recording apparatus that records an image on a recording medium by separating and discharging toner particles from ink by forming a predetermined electric field between the recording medium and the medium.

[0002]

2. Description of the Related Art Conventionally, ink jet recording methods include a piezo piezoelectric method, a thermal (bubble) method, an electrostatic acceleration method, and the like.

[0003] Among them, an ink jet recording method using static electricity is based on supplying ink into a nozzle or a slit-shaped ink holding portion having a large number of electrodes and selectively applying a high voltage to the nozzles and the electrodes. Ink is ejected onto a recording medium that is in close proximity to a nozzle or an electrode to record an image.

Here, the ink is 10 ⁶ to 10 ⁸ Ω · c.
A material having an electric resistance of about m is generally used, and a material in which a coloring agent composed of a pigment or a dye is dispersed in an oily solvent with a dispersing aid to adjust the resistance value is used.

[0005] The principle of the ink flying is that a high voltage applied to the electrode causes electric charge to be injected into the ink in contact with the electrode,
It is interpreted that the ink is charged and the electric field causes the ink to be ejected. Therefore, the ink is not normally charged, and only when a voltage is applied, the ink near the electrodes is charged to obtain the ejection force.

As can be seen from the above description, in this ink jet recording method, all components (solvent, colorant, dispersion aid) in the ink are consumed together.

[0007]

Some of the above-described ink jet recording techniques are small in size and consume little power, and have become remarkably popular in the personal field. However, there are many common problems to be solved in the ink jet recording technology. First, since a dye is used as a coloring component, the color is remarkably faded to sunlight, and it is difficult to use it for long-term recording. Secondly, since a carrier liquid ink having high fluidity is used, an image defect called bleeding or feathering occurs on a recording medium such as paper as an image receiving body. Therefore, an image receiving paper coated with silica or a water-soluble binder must be used as a recording medium, and there is a problem that the recording medium cannot be freely selected.

To solve such a problem, for example, Japanese Patent Application Laid-Open No. Sho 62-5282 discloses a recording apparatus using an ink in which charged coloring material particles are dispersed in an insulating liquid. ing. In this recording apparatus, ink is supplied to a recording electrode arranged opposite to a recording medium, and a bias voltage is applied to the recording electrode to which the ink is supplied, so that toner particles are proximate to the leading end of the recording electrode. Aggregation is performed, and the aggregate is separated and discharged from the insulating liquid toward the recording medium by electrostatic force, thereby recording an image on the recording medium.

However, with such a technique, although the bleeding or the like is small and the conventional problem can be solved, the ink discharge amount varies depending on the image recording pattern,
There was a problem that a uniform dot shape could not be obtained and image quality deteriorated.

Also, problems such as securing reliability (prevention of toner particles in ink from adhering to recording electrodes), high-speed recording (improvement of recording sensitivity) and improving image quality (prevention of ink transfer in non-recording pixels). It was difficult to meet everything.

Accordingly, the present invention provides an ink jet recording apparatus capable of always discharging a fixed amount of ink regardless of the recording pattern of a pixel group before the pixel of interest and obtaining a high quality image with a uniform dot diameter. The purpose is to do.

Further, according to the present invention, irrespective of the recording pattern of the pixel group before the pixel of interest, it is possible to prevent sticking of the toner particles, to obtain the ink ejection in good response to the recording pulse, and to obtain the unnecessary ink by the bias pulse. It is an object of the present invention to provide an ink jet recording apparatus capable of preventing ejection, obtaining a recording electrode with high reliability and a high quality image.

[0013]

According to the present invention, there is provided an ink jet recording apparatus for supplying an ink obtained by dispersing charged coloring agent particles in an insulating liquid to a recording electrode provided opposite to a recording medium. Supply means, and by forming an electric field between the recording electrode and the recording medium according to an image signal to be recorded, the coloring means particles in the ink supplied to the recording electrode by the supply means Electric field forming means for discharging toward a recording medium, and electric field controlling means for changing an electric field between the recording electrode and the recording medium formed by the electric field forming means according to a recording pattern of an image. I have.

Further, the ink jet recording apparatus of the present invention comprises a supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium. Forming an electric field between the recording electrode and the recording medium by applying a pulsed voltage to the recording electrode in accordance with an image signal to be recorded; and supplying the ink supplied to the recording electrode by the supply unit. An electric field forming unit for discharging the colorant particles therein toward the recording medium, and a pulse width control unit for controlling a pulse width of a voltage applied to the recording electrode in accordance with an image recording pattern.

Further, the ink jet recording apparatus of the present invention comprises a supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium. Forming an electric field between the recording electrode and the recording medium in accordance with an image signal to be recorded, thereby directing the colorant particles in the ink supplied to the recording electrode by the supply unit toward the recording medium. An electric field forming means for ejecting the recording electrode, an electric field applying means for changing the electric field between the recording electrode and the recording medium to such an extent that the ink is not ejected, and the recording electrode and the recording provided by the electric field applying means. Electric field control means for controlling a change in an electric field between the medium and the medium in accordance with an image recording pattern.

Further, the ink jet recording apparatus of the present invention comprises a supply means for supplying an ink in which charged colorant particles are dispersed in an insulating liquid to a recording electrode provided opposite to a recording medium. Forming an electric field between the recording electrode and the recording medium by applying a pulsed voltage to the recording electrode in accordance with an image signal to be recorded; and supplying the ink supplied to the recording electrode by the supply unit. An electric field forming means for discharging the colorant particles in the recording medium toward the recording medium; and applying a pulse-like voltage having substantially the same voltage as that for discharging the ink to the recording electrode, thereby forming the recording electrode and the recording medium. Between the recording electrode and the recording medium provided by the electric field applying means for giving a change in the electric field to such an extent that the ink is not ejected. It is and a electric field control means for controlling in response to the over down.

According to the present invention, by controlling the width of the recording pulse applied to the recording electrode of the pixel of interest in accordance with the recording pattern of the pixel group before the pixel of interest, the recording pattern of the pixel group before the pixel of interest is controlled. Instead, a constant amount of ink can always be ejected and recorded on a recording medium, so that a high-quality image with a uniform dot diameter can be obtained.

Further, according to the present invention, the bias pulse applied to the recording electrode of the target pixel is controlled in accordance with the recording pattern of the pixel group before the target pixel, so that the recording pattern of the pixel group before the target pixel is controlled. In addition, it is possible to prevent toner particles from sticking and to discharge ink satisfactorily in response to a recording pulse, and to prevent unnecessary discharge of ink by a bias pulse. it can.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment will be described.

FIG. 1 schematically shows the structure of an ink jet recording apparatus according to the present invention. In FIG.
The inkjet recording apparatus 1 includes yellow Y, magenta M, cyan C, and black BK recording heads 2, 3,
By ejecting ink from 4 and 5 toward the transfer belt 6 also serving as the counter electrode, an image is formed on the transfer belt 6 once, and the image is collectively transferred onto the paper An image is formed on P.

The recording heads 2, 3, 4, and 5 of each color are connected to ink reservoirs 7, 8, 9, and 10 corresponding to the respective colors via an ink circulation mechanism (only Y is shown). For example, regarding the recording head 2 of Yellow Y,
Ink is circulated between the recording head 2 and the ink reservoir 7 through tubes 13 and 14 using an ink supply pump 11 and an ink recovery pump 12. The same applies to recording heads of other colors.

The operations of driving and controlling the recording heads 2, 3, 4, and 5, circulating the ink, and transporting the transfer belt 6 and the sheet P are controlled by a control unit (not shown) and a power supply in the ink jet recording apparatus 1, respectively. Is being done. The transfer belt 6 is stretched between rollers 15 and 16 and is transported and driven by a driving device (not shown) in the direction of the arrow in the figure (clockwise in the figure).

The transfer speed of the transfer belt 6 and the recording heads 2
By synchronizing with the ink ejection frequencies of 3, 4, and 5, an image corresponding to the image data can be obtained on the transfer belt 6. The ink ejection points of the recording heads 2, 3, 4, and 5 are arranged at a density lower than the recording resolution. For this reason, while conveying the transfer belt 6 a plurality of times,
By scanning the recording heads 2, 3, 4, and 5 in the depth direction of the paper, an image of the entire surface is formed.

A transport unit for the paper P on which an image is finally formed is a paper feed cassette 1 for storing the paper P before recording.
7, take-out rollers 18 for taking out the paper P one by one from the paper feed cassette 17, a group of transport rollers 19 for transporting the taken-out paper P, a guide plate 20 for guiding the transported paper P, and an image on the transfer belt 6 for the paper P Fixing roller 21 for transferring and fixing the image thereon, and tray 2 for receiving sheet P after image formation
2 is provided.

During image formation on the transfer belt 6, the fixing roller 21 is separated from the transfer belt 6. After the image is formed on the transfer belt 6, the fixing roller 21 comes into contact with the image. At this time, the fixing roller 21 is heated by the heater 23 to adjust the temperature to a temperature range of 80 to 200 ° C. in order to promote the transfer and fixing of the image onto the paper P.

Here, the ink used in the present embodiment will be described. In the present embodiment, as the ink,
An isoparaffin-based solvent which is an insulating carrier liquid (for example, isoper G, H, L / electric resistance of 10
^In an insulating dispersion medium (hereinafter, referred to as a carrier liquid) composed of ¹² to 10 ¹³ Ω · cm or more, having a particle diameter of about 0.01 to 5 μm, and having a predetermined polarity in the carrier liquid;
Resin particles having at least a coloring component (hereinafter, referred to as toner particles) are dispersed at a concentration by weight of 10% or less. Such an ink is basically the same as a carrier liquid developer used in electrophotography and the like, but requires a higher electric resistance of the liquid.

When such an ink is directly transferred to a sheet in this state, only an image having a low density can be obtained. The reason is that the concentration of the toner particles (hereinafter referred to as toner concentration) is low at the above value, and the amount of the toner particles as the color material is insufficient. However, if the toner concentration is increased in the initial state, the viscosity also increases, so that it becomes difficult to transport the ink.

Therefore, in the present embodiment, when the ink is supplied from the ink tank to the recording head and the ink is conveyed to the recording head, the toner particles are concentrated at a low concentration immediately before the ink is ejected from the recording head. Is transferred to paper.

Next, the recording heads 2, 3, 4, and 5 will be described. Since the recording heads 2, 3, 4, and 5 have the same configuration, the recording head 2 will be described as a representative.

In FIG. 2, the recording head 2 includes a plurality of ink supply paths 31 (see FIG. 3), two recording electrode substrates 33 each having a plurality of recording electrodes 32 on the respective ink supply path surfaces, and ink A film-shaped ink guide 35 formed of a dielectric material leading to the discharge point 34 is provided. In this case, the ink guide 3 is provided between the two recording electrode substrates 33.
5 is sandwiched, and the tip 35a of the ink guide 35 projects from the opening of each ink supply path 31.

The ink supplied to the ink supply path 31 is
As shown by an arrow 36 in the figure, the ink overflows from the opening of the ink supply path 31 and flows down the slope 33 a of the recording electrode substrate 33. Until the ink travels from the ink supply path 31 through the ink guide 35 to reach the ink discharge point 34, the ink is prevented from mixing with the ink in the adjacent ink supply path 31 by the partition wall 37 between the ink supply paths 31. .

FIG. 3 is a longitudinal sectional view of the recording heads 2, 3, 4, and 5, and will be described in more detail with reference to FIG. The ink is supplied by a pump (not shown) from the inlet of the ink supply path 31 in the direction of arrow 38, overflows from the opening of the ink supply path 31, and flows out of the slope 33 a.
Flows down in the direction of the arrow 36 and is stored in the common ink chamber 39. Further, the ink is pumped by a pump (not shown).
The ink is sucked out of the common ink chamber 39 in the direction of arrow 40 and collected by the ink reservoirs 7, 8, 9, and 10.

During the recording operation, since the ink is constantly flowing, a sufficient amount of toner particles can be supplied to the ink discharge point 34. The meniscus 41 at the tip 35a of the ink guide 35, which is the ink discharge point 34, is almost stationary due to the surface tension of the ink and the wetting with the ink guide 35. For this reason,
At the ink discharge point 34, the meniscus 41 does not vibrate and stable ink discharge becomes possible. Furthermore, ink guide 3
5 is thinner toward the front end, so that the toner particles are efficiently aggregated and concentrated when moved to the ink discharge point 34 at the front end.

FIG. 4A shows recording heads 2, 3, 4, and 5
FIGS. 4B and 4C are diagrams schematically showing the electric field and the equipotential surface near the ink discharge point of FIG. 4, and FIGS. 4B and 4C are diagrams schematically showing the behavior of the toner particles.

First, the relationship between the potential of the recording electrode 32 (hatched portion) and the potential of the transfer belt 6 as the counter electrode will be described assuming that the charging polarity of the toner particles is positive. When the operation of the apparatus starts and ink is not ejected, a potential V1 is applied to the recording electrode 32 and a potential V0 is applied to the counter electrode (transfer belt) 6, and the relationship between the two potentials is [V0 <V1. ].

At this time, the recording electrode substrate 33, the recording electrode 3
2, an equipotential line a and an electric field b are formed between the electrodes 6 and 32 depending on the shape and the dielectric constant of the counter electrode 6 and the ink meniscus 41, as shown in FIG. Next, when ink is ejected, the potential relationship is [V0 <V1 <V2].
Is applied to the recording electrode 32. Also at this time, the equipotential lines become dense and the electric field becomes strong, but the distribution is almost the same.

FIG. 4B is a diagram schematically showing the behavior of the toner particles when the voltage V1 is applied to the recording electrode 32. As described above with reference to FIG. 3, when the ink overflows from the opening of the ink supply path 31, the positively charged toner particles are electrically moved in the direction of the counter electrode 6 by the electric field shown in FIG. It moves by electrophoresis, is further guided to the surface of the ink, and aggregates at the front end 35 a of the ink guide 35. Further, the voltage V1 is set to a potential at which the Coulomb force received by the toner particles in the electric field at this time is weaker than the surface tension and the ink is not ejected.

Here, even when the ink is not ejected, an electric field is formed on the opposite electrode 6 by applying the potential V1 to the recording electrode 32 (DC bias), so that the toner particles are constantly applied to the tip 35a of the ink guide 35. Since the concentration can be achieved, the discharge frequency can be increased, and the switching voltage can be reduced, the drive circuit can be reduced in size and cost can be reduced.

FIG. 4C is a diagram schematically showing the behavior of the toner particles when the voltage V2 is applied to the recording electrode 32. In this case, a stronger electric field is generated than in the case of FIG. By the action of this strong electric field,
The Coulomb force received by the toner particles exceeds the surface tension of the ink, and the ink droplet 42 comes off the recording electrode 32. The detached ink droplet 42 flies toward the counter electrode 6 and is transferred to a sheet. At this time, since the ink droplets 42 that fly and transfer have agglomerated toner particles, a large amount of solid components, and a high concentration, they do not flow and bleed on the transfer belt 6 in the surface direction.

Further, from the state where the potential V1 which is a DC bias is applied to the recording electrode 32, the state shown in FIG.
When the electric potential V2 is applied, an electric field acts on the charged toner particles to move in the direction of the counter electrode 6 to overcome the surface tension of the liquid surface and to discharge, but the carrier liquid also has the surface tension and viscosity. As a result, the toner particles move together with the toner particles, and the meniscus 41 rises to the counter electrode 6.

Next, when the application of the potential V2 ends, the ejection of the ink also ends, and the meniscus 41 also attempts to restore the state of FIG. 4B where the potential V1 is applied. Since the ejection of ink is a phenomenon that occurs in a very small region of the tip end portion 35a of the ink guide 35, the cycle is short, but the meniscus 4
1 is much larger than the area where ink is ejected over the entire opening of the ink supply path 31 and the restoration cycle is long. Therefore, when recording (ink ejection) is performed at a certain pixel, the meniscus 41 is restored. Requires a plurality of non-recording pixels.

For this reason, the meniscus 41 at the time when the operation of ejecting ink starts is different depending on the presence or absence of the recording before the pixel and the recording pattern, and the same V is applied to the recording electrode 32.
Even if 2 (potential, pulse width) is applied, the amount of ink to be ejected fluctuates, resulting in deterioration of image quality.

More specifically, when pixels for which recording is not performed before that pixel continue, the meniscus 41 becomes the counter electrode 6.
, The time from when the potential V2 is applied to the recording electrode 32 to when the ink is ejected is long, and the ink ejection amount is small. Further, when the pixels to be recorded before the pixel continue, the meniscus 41 is located at a position close to the counter electrode 6, the time from when the potential V2 is applied to the recording electrode 32 to when the ink is ejected is short, and the ink ejection is performed. Large amount.

FIG. 5 is a timing chart showing the relationship between the potentials of the recording electrodes in the recording operation of the present embodiment in comparison with the conventional example.

FIG. 5A shows the potential of the recording electrode of the conventional example, and the recording cycle is the time for recording one pixel, and the potential (A) of V2 (A) is applied to the pixel for recording (ink ejection) according to the image data. (Hereinafter, a pulse voltage applied to a recording electrode for recording according to image data is referred to as a recording pulse).

FIG. 5B shows the potential of the recording electrode according to the present embodiment, and FIG. 5A shows that a recording pulse is applied to a pixel which performs recording (ink ejection) according to image data. In the same manner, the potential V2 for a long time is applied to the recording electrode at the first pixel (location B) of the image and at the pixel (location C) where the non-recording pixels continue before itself. As a result, even when the meniscus is located at a position distant from the counter electrode, the time during which a strong electric field acts on the toner particles becomes longer, and a predetermined amount of ink can be ejected.

Here, at the position C, the pulse width for applying the potential V2 is increased when the three pixels preceding the pixel are not recorded, but the condition for increasing the pulse width is that of the meniscus. It is necessary to change the size, the target ink ejection amount, the characteristics of the ink, and the like.

The pulse width (pulse width of a recording pulse) of a pixel to be recorded is controlled not only by simply recording unrecorded pixels but also by a recording pattern such as non-recording-recording-non-recording. Thus, the amount of ink to be ejected can be made uniform regardless of the recording pattern.

FIG. 5C also shows the potential of the recording electrode of the present embodiment, and FIG. 5A shows that the recording pulse is applied to the pixel that performs recording (ink ejection) according to image data. Same pixels, but pixels (D,
At (E), a short-time potential V2 is applied to the recording electrode. As a result, even when the meniscus is close to the counter electrode, the time during which a strong electric field acts on the toner particles is shortened, and a predetermined amount of ink can be ejected.

Here, at the point D, the pulse width for applying the potential V2 is shortened when three pixels before the self are recorded, and the pulse width is further shortened when three pixels are continuous. However, the conditions for shortening the pulse width also need to be changed according to the size of the meniscus, the target ink ejection amount, and the ink characteristics as described above.

The amount of ink to be ejected is controlled by controlling the pulse width of the pixel to be recorded in accordance with a recording pattern such as recording-non-recording-recording, for example, not only when the recorded pixels are continuous. It is possible to make it uniform regardless of the pattern.

FIG. 6 is a block diagram of an ink jet recording apparatus according to the present invention. In FIG. 6, the CPU
The (central processing unit) 51 controls the operation of the entire apparatus, and its operation and control procedure are stored in a ROM (read only memory) 52. The user operates the present apparatus via the control panel 53. Input interface (I / F)
Reference numeral 54 is used to communicate and transfer image data and control data from an external image input and editing device such as a scanner or a personal computer.

RAM (Random Access Memory) 5
Reference numeral 5 is used as a working memory when storing image data transferred from an external image device and when processing image data to be described later. The pulse generating circuit 56 converts the image data stored in the RAM 55 into a pulse, and transfers the pulse to the driving circuit 57 of the recording heads 2, 3, 4, and 5. A high-voltage power supply 58 is connected to the drive circuit 57, and the drive circuit 57 switches the voltage from the high-voltage power supply 58 according to a pulse transferred from the pulse generation circuit 56.

The paper / transfer belt control circuit 59 controls the operation of the motor 60 for driving the transfer belt 6, and the pump control circuit 61 controls the operations of the pumps 11 and 12, respectively.

FIG. 7 illustrates a method of converting image data transferred from an external image device into image data with a corrected pulse width as shown in the timing charts of FIGS. 5B and 5C. FIG. Here, in order to simplify the description, the image data of one recording electrode is arranged from top to bottom in the recording order.

FIG. 7A shows, before correction, the presence or absence of the recording of FIG. 5B by two values of 1 (recording) and 0 (non-recording). FIG. 7B shows the state after the correction, as shown in FIG.
This is image data whose pulse width has been corrected by the previous recording pattern. Pixels that do not need correction are converted to image data of “04” and pixels that need correction are converted to image data of “07”.

Here, the case of recording (1) with the first pixel and the case of non-recording (0)
When the user is the record (1), the data of “1” is “0”.
7 ". In addition,
In FIG. 7, the pixels A and B are corrected.

FIG. 7 (c) shows the presence or absence of the recording of FIG. 5 (c) by two values of 1 (recording) and 0 (non-recording) before correction. FIG. 7D shows, after the correction, as shown in FIG.
This is image data whose pulse width has been corrected by the previous recording pattern. Pixels that do not require correction are converted to image data of “04”, and required pixels are converted to image data of “03” or “02”.

In this case, when three pixels before the subject are successively recorded (1) and the subject is the recorded (1),
The data of "1" is converted to "03", and further six pixels are continuously recorded (1), and when the self is the recording (1), the data of "1" is converted to "02". Is programmed as In FIG. 7, C and D pixels are corrected.

FIG. 8 shows a configuration of the pulse generating circuit 56 for applying the corrected image data shown in FIG. 7 to the recording electrodes 32 as recording pulses having different pulse widths.
The pulse generation circuit 56 divides one recording cycle into scanning of a plurality of sub-lines, and varies the pulse width by changing the number of sub-lines in which recording pulses are generated. The write control circuit 71, two FIFOs 72, 73, read control circuit 7
4, a sub-line counter 75, and a memory 76.

The image data is written into the FIFO selected by the write control circuit 71. The HSYNC signal generated every recording cycle is input to the write control circuit 71. When the HSYNC signal is input, the FIFO for writing the image data is switched.

On the other hand, the read control circuit 74 has the same HS
The FNC to which the YNC signal is input and which is to be read
O is switched. Further, image data for each one line (the direction of arrangement of the recording electrodes of the recording head) is stored in the FIFO.
And the other is read, this operation is performed by two F
The operations are alternately performed by the IFOs 72 and 73.

The sub-line counter 75 counts a sub-line clock sent from a timing circuit (not shown), and the value is cleared by the HSYNC signal. In the present embodiment, seven counts are performed in one recording cycle, and the output of the sub-line counter 75 is input to the memory 76.

The read operation from the FIFOs 72 and 73 is as follows.
It is performed eight times within one recording cycle in synchronization with the counting operation of the sub-line counter 75. The data read by these eight reading operations is the same data. The read data is supplied to the memory 76 as an address.

FIG. 9 shows a memory 7 built in a pulse generating circuit 56 for generating a pulse as shown in FIGS.
FIG. The memory 76 stores the address of the sub-line counter 75 described above as an address,
Read data from O72 and O73 is input. The role of the memory 76 is to output pulse generation data to the drive circuit 57 of the recording head using the value of the image data and the value of the sub-line counter 75 as address inputs.

In the memory map, a data area is divided according to image data. That is, the address "000
0H ”to“ 0007H ”means that the image data is“ 00 ”
The addresses “0100H to“ 0107H ”correspond to the image data“ 01 ”and the addresses“ 0700H ”to“ 0707 ”.
“H” stores pulse generation data with image data “07”.

The distribution of addresses in the memory 76 will be described in more detail.
Bits are assigned to outputs of the sub-line counter 75, respectively. In the present embodiment, only the lower 3 bits of the upper 8 bits are allocated to the image data, and the upper 5 bits are fixed to “0”. Further, since the number of sub-lines is "8", only the lower 3 bits of the lower 8 bits are allocated, and the upper 5 bits are fixed to "0".

Here, when the image data is "00",
Access is made from addresses "0000H" to "0007H". That is, when the value of the sub line counter 75 is “0”, the data “0” stored at the address “0000H” is transferred to the drive circuit 57 of the print head. Further, as the value of the sub-line counter 75 is incremented by one, the value is “0” when “1”, “0” when “2”,. "0" is output.

When the image data is "07", the addresses "0700H" to "0707H" are accessed. When the value of the sub line counter 75 is "0" to "6", "1" is changed to "7". In this case, "0" is output. Similarly, when the image data is “01”, “02”,..., “06”, appropriate data is written in the address accessed by the image data and the value of the sub-line counter 75.

"1" is set according to the output pulse data.
In this case, the pulse width can be varied according to the image data by switching so that the potential V2 is applied to the recording electrode 32 when the potential V2 is "0".

As described above, the image data transferred from the external image device is corrected according to the recording pattern before the pixel of interest, and the number of sub-lines in which a recording pulse is generated in one recording cycle is controlled. The width can be varied.

As described above, according to the first embodiment, the pulse width of the recording pulse applied to the recording electrode of the target pixel is controlled in accordance with the recording pattern of the pixel group before the target pixel. Regardless of the recording pattern of the pixel group before the target pixel, a constant amount of ink can always be ejected and transferred to paper, so that a high-quality image with a uniform dot diameter can be obtained.

In particular, when there is a means for controlling the pulse width of the recording pulse applied to the recording electrode according to the recording pattern of the image, and there is a recording pixel after a predetermined number of non-recording pixels continue on the same recording electrode, By increasing the pulse width of the recording pulse applied to the recording electrode, the same dot diameter as other recording patterns can be obtained.

Further, when there is another recording pixel after a predetermined number of recording pixels are continuously arranged on the same recording electrode, the pulse width of the recording pulse applied to the recording electrode is shortened so that the same dot diameter as other recording patterns can be obtained. Obtainable.

Next, a second embodiment will be described.

The difference between the second embodiment and the first embodiment is that the application of the bias pulse applied to the recording electrode of the target pixel is controlled according to the recording pattern of the pixel group before the target pixel. This will be described in detail below.

FIG. 10 is a diagram for explaining the adhesion of toner particles to the ink guide 35. Even when the ink is not ejected, if a DC bias that causes a constant potential difference between the recording electrode 32 and the counter electrode 6 is applied, in a recording pattern in which non-recording pixels are continuous, the toner particles remain in the ink for a long time. The state is such that the guide stays at the distal end portion 35a of the guide 35.

In this state, the toner particles are pressed against and adhere to the ink guide 35 and hinder the subsequent supply of the toner particles. This is presumably because the newly supplied toner particles are repelled by the charge of the toner particles attached to the ink guide 35. In the experiment, when the printing operation is once finished, the meniscus returns to the ink supply path 31, and then the ink is again supplied to the tip portion 35a of the ink guide 35, and the printing operation is performed, the ejection frequency decreases. Such as deterioration of recording characteristics.

FIG. 11 is a diagram for explaining a recording method for solving the problem described in FIG. 10, and is a timing chart showing the relationship between the potentials of the recording electrodes in the recording operation. As the potential of the counter electrode 6, V0, which is a negative potential during the recording operation, is applied although not shown. The potential of the recording electrode 32 is normally V1 (for example, 0 V), and the potential of V2 (for example, 60 V) in a cycle of a pixel for recording (ink ejection).
0V) is applied.

In the period of a pixel that does not eject ink, a voltage that is shorter than the recording pulse 81 at a potential of V2 at the recording electrode 32 and that does not eject ink (hereinafter referred to as a bias pulse) 82 is applied to the recording electrode 32. Is applied, and the electric field periodically fluctuates between the recording electrode 32 and the counter electrode 6.

FIG. 12 is a diagram schematically showing the behavior of toner particles in ink at the tip 35a of the ink guide 35 when the bias pulse 82 is applied. FIG.
(A) shows the movement of the toner particles when the potential of the recording electrode 32 becomes V2 as the bias pulse 82. Due to the electric field from the recording electrode 32 to the counter electrode 6,
The toner particles are at the tip 3 of the ink guide 35 having a low potential.
Although the toner particles move to the position 5a and aggregate, the number of aggregated toner particles does not simply increase. When a certain number of toner particles aggregate at the front end 35a of the ink guide 35, the charge of the aggregated toner particles and the ink The toner particles coming out of the supply path 31 repel each other and return in the direction of arrow C in the figure.

As described above, the amount of toner particles that can be aggregated on the tip 35a of the ink guide 35 is limited by the relationship between the potential of the recording electrode 32 and the potential of the counter electrode 6. In this state, the application of the bias pulse 82 is completed, and the potential of the recording electrode 32 becomes V
FIG. 12B shows the movement of the toner particles when the number of the toner particles becomes 1. FIG. 12A shows a state in which the recording electrode 32 and the counter electrode 6
Is large as [V2−V0], a large amount of toner particles can be aggregated at the tip portion 35a of the ink guide 35. However, in FIG. 12B, the potential difference becomes small as [V1−V0]. The particles cannot be aggregated at the leading end 35a of the ink guide 35 as in the state of FIG.

As described above, by changing the potential difference between the recording electrode 32 and the counter electrode 6, that is, the intensity of the electric field,
The toner particles in the vicinity of the tip of the ink guide 35 can be moved.

As described above, by applying the bias pulse 82 and periodically oscillating the toner particles at the tip 35a of the ink guide 35, the toner particles
The recording characteristics can be prevented from deteriorating even when used for a long time. In addition, when the bias pulse 82 is applied to the recording electrode 32, the ejection response of the ink is improved, and the switching voltage, which is the potential difference between V1 and V2, can be reduced. Therefore, a small and low-cost switching element can be used. it can.

However, if the pulse width of the bias pulse 82 is set too short, the above-described effects cannot be obtained. If the pulse width is long, and if the non-recording pixels continue, the application of the bias pulse 82 Is ejected, unnecessary transfer of ink to an image occurs, and the image quality deteriorates. As described above, the application condition of the bias pulse 82 that achieves both the effect of the bias pulse 82 and high image quality is only in a very small range, and it is difficult to adjust.

FIG. 13 is a timing chart showing the relationship between the potentials of the recording electrodes in the recording operation of the present embodiment in comparison with the conventional example.

FIG. 13A shows the conventional recording method described with reference to FIG. 11, in which the potential of the recording electrode such that a constant electric field fluctuation always occurs between the recording electrode and the counter electrode regardless of the recording pattern. Is shown.

FIG. 13B shows the potential of the recording electrode according to the present embodiment.
A bias pulse 82 having a potential of V2 and a pulse width shorter than the recording pulse 81 is applied to the recording electrode, and the electric field periodically fluctuates between the recording electrode and the counter electrode. The application is not performed.

FIG. 13C shows another example of the present embodiment, in which the cycle of applying the bias pulse 82 is increased according to the recording pattern. Normally, the bias pulse 82 is applied twice in one recording cycle, but here it is applied once.

FIG. 13D shows another example of the present embodiment, in which the time for applying the bias pulse 82 according to the recording pattern, that is, the pulse width is shortened.

What is common in FIGS. 13B to 13D is that focusing on a certain pixel, the pixel does not record, and if there is a pixel which does not record before that pixel, the pixel faces the recording electrode. That is, the bias pulse 82 is controlled so as to reduce the fluctuation of the electric field between the electrode and the electrode.

Specifically, in FIGS. 13B to 13D,
Focusing on the pixel corresponding to the recording cycle A, if the pixel of interest is non-recording and three pixels corresponding to the preceding recording cycles B, C, and D are successively non-recording, FIG. )
In FIG. 13 (c), the period is lengthened, and in FIG. 13 (d), the time for fluctuation is shortened.

As a result, the pulse width of the normal bias pulse 82 can be set to a length sufficient to prevent toner particles from adhering to the ink guide and to obtain ink ejection in response to the recording pulse 81. , Even if non-recording pixels continue,
Ink is not ejected by the bias pulse 82, and both the reliability of the recording head and the improvement of image quality can be achieved.

In the above description, as a specific embodiment, when a plurality of non-recording pixels continue before the pixel of interest, the bias pulse is controlled so as to reduce the electric field in the direction of the counter electrode. However, the ink is ejected by the bias pulse not only when the non-printed pixels are continuous but also when the ratio of the non-printed pixels in a certain continuous pixel group is high.

In such a case, the amount of toner particles concentrated at the tip of the ink guide is large, and ink is ejected even with a bias pulse. Therefore, in order to satisfy both the toner particle fixation of the ink guide and the ink discharge by the bias pulse, it is not necessary to consider only the continuous number of non-recording pixels,
It is necessary to consider the ratio of non-printed pixels in a certain continuous pixel group.

FIG. 14 is another timing chart showing the relationship between the potentials of the recording electrodes in the recording operation of the present embodiment in comparison with the conventional example.

FIG. 14A shows the conventional recording method described with reference to FIG. 11, in which the potential of the recording electrode is such that a constant electric field variation always occurs between the recording electrode and the counter electrode regardless of the recording pattern. Is shown.

FIG. 14B shows the potential of the recording electrode according to the present embodiment.
A bias pulse 82 having a potential of V2 and a pulse width shorter than that of the recording pulse 81 is applied to the recording electrode, and the electric field periodically fluctuates between the recording electrode and the counter electrode. The application cycle is shortened.

FIG. 14C shows another example of the present embodiment, in which the time for applying the bias pulse 82 according to the recording pattern, that is, the pulse width is increased.

What is common in FIGS. 14 (b) and 14 (c) is that, noting a certain pixel, the pixel does not record, there is a pixel that does not record before that pixel, and the pixel that records after that is not recorded. In other words, the bias pulse 82 is controlled so as to increase the fluctuation of the electric field between the recording electrode and the counter electrode.

More specifically, in FIGS. 14B and 14C, when attention is paid to the pixel corresponding to the recording cycle A, the pixel of interest is non-recording and further corresponds to the preceding recording cycles B, C, and D. Three non-recording pixels are continuously non-recorded, and E after the two pixels
14B, the period of the fluctuation of the electric field is shortened in FIG. 14B, and the period of the fluctuation is increased in FIG. 14C.

Thus, the pulse width of the normal bias pulse 82 is such that the toner particles do not adhere to the ink guide and ink is not ejected even when non-recording pixels continue, and the response is good even for recording pixels. Ink can be ejected, and both the reliability of the recording head and the improvement in image quality can be achieved.

In the above description, as a specific embodiment, when a plurality of non-recording pixels continue before the pixel of interest and there is a recording pixel after a predetermined number of pixels, the electric field in the direction of the counter electrode becomes strong. Although the bias pulse is controlled so that the non-recording pixel becomes difficult to eject in response to the recording pulse, it is not always the case that the non-recording pixel in the continuous pixel group is not only when the non-recording pixel is continuous. This is the case when the ratio is high.

In such a case, the concentration of the toner particles at the tip of the ink guide is small, and the ink is not ejected even by the recording pulse. Therefore, in order to satisfy all of the prevention of toner particle sticking of the ink guide, the prevention of ink ejection by the bias pulse, and the favorable ink ejection by the recording pulse, it is not necessary to consider only the continuous number of non-recording pixels, but rather continuous. It is necessary to consider the ratio of non-recording pixels in the pixel group.

FIG. 15 illustrates a method of converting image data transferred from an external image device into image data with a corrected pulse width as shown in the timing charts of FIGS. 13 (b) to 13 (d). FIG. Here, in order to simplify the description, the image data of one recording electrode is arranged from top to bottom in the recording order.

FIG. 15A shows a state before correction and FIG.
Is represented by two values, 1 (recorded) and 0 (non-recorded).

FIG. 15B shows the state after the correction shown in FIG.
13 (b) to 13 (d) show image data in which the bias pulse has been corrected by the previous recording pattern as shown in FIG.
(D) In any case, the application pattern of the recording pulse and the bias pulse within one recording cycle is as follows:
(2) normal bias pulse application, (3) corrected bias pulse application, each of which is "00H",
The image data “01H” and “02H” correspond.

Here, the non-recording (0) is usually converted to “01”, but when the three pixels preceding the self are non-recording (0) consecutively, for example, the pixels A and B are It is programmed so that data of “0” is converted to “02”.

FIG. 16 illustrates a method of converting image data transferred from an external image device into image data with a corrected pulse width as shown in the timing charts of FIGS. FIG. Here, in order to simplify the description, the image data of one recording electrode is arranged from top to bottom in the recording order.

FIG. 16A shows a state before correction and FIG.
The presence or absence of recording is represented by two values, 1 (recording) and 0 (non-recording).

FIG. 16B shows the state after the correction.
As shown in FIG. 14C, the image data is obtained by correcting the bias pulse according to the preceding and succeeding recording patterns.
(C) In either case, the application pattern of the recording pulse and the bias pulse within one recording cycle is as follows:
(2) normal bias pulse application, (3) corrected bias pulse application, each of which is "00H",
The image data “01H” and “02H” correspond.

Here, the non-recording (0) is usually converted to “01”, but the three pixels preceding the self are consecutively non-recording (0), and the subsequent one or two pixels are recorded. in the case of,
For example, the pixels A and B are programmed so that data of “0” is converted to “02”.

FIG. 17 is a diagram for explaining the memory 76 incorporated in the pulse generation circuit 56. The value of the sub-line counter 75 described above and the data read from the FIFOs 72 and 73 are input to the memory 76 as addresses. The role of the memory 76 is to output pulse generation data to the drive circuit 57 of the recording head using the value of the image data and the value of the sub-line counter 75 as address inputs.

In the memory map, a data area is divided according to image data. That is, the address "000
0H ”to“ 0007H ”means that the image data is“ 00 ”
The addresses “0100H to“ 0107H ”correspond to the image data“ 01 ”and the addresses“ 0200H ”to“ 0207 ”.
“H” stores pulse generation data whose image data is “02”.

The distribution of addresses in the memory 76 will be described in more detail.
Bits are assigned to outputs of the sub-line counter 75, respectively. In the present embodiment, only the lower 2 bits of the upper 8 bits are allocated to the image data, and the upper 6 bits are fixed to “0”. Further, since the number of sub-lines is "8", only the lower 3 bits of the lower 8 bits are allocated, and the upper 5 bits are fixed to "0".

Here, data of a memory for obtaining the timing chart of FIG. 13B is shown. When the image data is "00", that is, when a recording pulse is output, addresses from "0000H" to "0007H" are accessed. That is, the value of the sub-line counter 75 is “0”
In this case, the data “1” stored at the address “0000H” is transferred to the drive circuit 57 of the printhead.
Further, as the value of the sub-line counter 75 is incremented by one, "1" is output for "1", "1" is output for "2", and so on. In the case of “6” and “7”, “0” is output.

When the image data is "01", that is, when a normal bias pulse is output, the address "0100
H ”to“ 0107H ”, and“ 1 ”when the value of the sub-line counter 75 is“ 0, 1 ”or“ 4, 5 ”
In other cases, “0” is output.

When the image data is "02", that is, when the corrected bias pulse (in this case, no bias pulse is generated) is output, "0" is output as the value of all the sub-line counters 75. The drive circuit 57 to which the output data has been transferred outputs V2 when the data is “1”.
, Three patterns of pulse voltages are applied within one recording cycle.

The image data and the sub line counter 7
By writing appropriate data to the address accessed with the value of 5, the data shown in FIGS.
The timing chart of (c) is obtained.

As described above, the image data transferred from the external image device is corrected in accordance with the recording pattern before and after the pixel of interest, and the number of sub-lines in which one pulse is generated within one recording cycle is controlled, whereby the bias is increased. Control the pulse.

As described above, according to the second embodiment, by controlling the application of the bias pulse applied to the recording electrode of the pixel of interest in accordance with the recording pattern of the pixel group before the pixel of interest, Irrespective of the recording pattern of the pixel group before the pixel, it is possible to prevent the toner particles from sticking, discharge ink satisfactorily in response to a recording pulse, and prevent unnecessary ink discharge due to a bias pulse. High quality images can be obtained.

Further, by controlling the application of the bias pulse applied to the recording electrode of the pixel of interest in accordance with the recording pattern of the pixel group before and after the pixel of interest, it is possible to prevent the toner particles from sticking and to record regardless of the recording pattern. Since it is possible to prevent ejection of ink satisfactorily in response to a pulse and unnecessary ejection of ink due to a bias pulse, it is possible to obtain a high-quality image with high reliability of the recording head.

In the above-described embodiment, an image is formed on the transfer belt by discharging ink from the recording head toward the transfer belt also serving as the counter electrode, and the image is collectively transferred onto paper. Although the case where the present invention is applied to an ink jet recording apparatus of a system has been described, the present invention is not limited to this.For example, a counter electrode is provided facing a recording head, and a sheet is placed in front of the counter electrode. The present invention can be similarly applied to an ink jet recording apparatus of a type in which an image is formed directly on a sheet by discharging ink from a recording head toward a counter electrode.

In the above embodiment, the control for recording the next pixel after the target pixel according to the state before the target pixel is described. However, the control is not limited to the pixel immediately after the target pixel. It is needless to say that the image is recorded after the pixel and is close to the pixel of interest. These controls may be appropriately set according to the recording pattern of the image to be recorded.

[0126]

As described above in detail, according to the present invention, a fixed amount of ink is always ejected regardless of the recording pattern of the pixel group before the target pixel, and a high quality image with a uniform dot diameter is obtained. And an ink jet recording apparatus capable of performing the above.

Further, according to the present invention, regardless of the recording pattern of the pixel group before the pixel of interest, prevention of toner particles from sticking,
It is possible to provide an ink jet recording apparatus which can discharge ink satisfactorily in response to a recording pulse, can prevent unnecessary discharge of ink by a bias pulse, and can obtain recording electrode reliability and a high quality image.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing a configuration of an inkjet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the vicinity of an ink ejection point of a recording head.

FIG. 3 is a longitudinal sectional view of a recording head.

FIG. 4A is a schematic diagram illustrating an electric field and an equipotential surface near an ink discharge point of a recording head, and FIGS. 4B and 4C are schematic diagrams illustrating behavior of toner particles.

FIG. 5 is a timing chart showing a relationship between potentials of recording electrodes in a recording operation in comparison with a conventional example.

FIG. 6 is a block diagram of an inkjet recording apparatus.

FIG. 7 is a view for explaining a method of converting image data into image data having a corrected pulse width.

FIG. 8 is a block diagram illustrating a configuration of a pulse generation circuit that generates corrected image data as recording pulses having different pulse widths.

FIG. 9 illustrates a memory incorporated in a pulse generation circuit.

FIG. 10 is a diagram illustrating attachment of toner particles to an ink guide.

FIG. 11 is a diagram illustrating a conventional recording method.

FIG. 12 is a schematic diagram showing the behavior of toner particles at the tip of an ink guide when a bias pulse is applied.

FIG. 13 is a timing chart showing a relationship between potentials of recording electrodes in a recording operation of an ink jet recording apparatus according to a second embodiment of the present invention, as compared with a conventional example.

FIG. 14 is another timing chart showing the relationship between the potentials of the recording electrodes in the recording operation of the ink jet recording apparatus according to the second embodiment in comparison with the conventional example.

FIG. 15 is a view for explaining a method of converting image data into image data having a corrected pulse width as in the timing charts shown in FIGS. 13 (b) to 13 (d).

FIG. 16 is a view for explaining a method of converting image data into image data having a corrected pulse width as in the timing charts shown in FIGS. 14 (b) and (c).

FIG. 17 illustrates a memory incorporated in a pulse generation circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink jet recording apparatus, 2-5 ... Recording head, 6 ... Transfer belt (counter electrode), 21 ... Fixing roller, P ... Paper (recording medium), 31 ... Ink supply path,
32 recording electrode, 35 ink guide 39 common ink chamber 41 meniscus 51 CPU 5
6 pulse generating circuit, 57 driving circuit, 58 high-voltage power supply, 81 recording pulse, 82 bias pulse.

Claims (13)

[Claims] A supply unit configured to supply an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium; By forming an electric field between the recording electrode and the recording medium, an electric field forming means for discharging colorant particles in the ink supplied to the recording electrode by the supply means toward the recording medium, An ink jet recording apparatus comprising: an electric field control unit that changes an electric field between the recording electrode and the recording medium formed by the electric field forming unit according to a recording pattern of an image. 2. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An ink jet recording apparatus comprising: an electric field forming unit configured to discharge toward a medium; and a pulse width control unit configured to control a pulse width of a voltage applied to the recording electrode according to a recording pattern of an image. 3. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for discharging toward the medium; a target pixel of the same recording electrode is a recording pixel; and if n of the m pixel groups before the target pixel are non-recording pixels, the recording electrode of the target pixel is And a pulse width control unit for controlling a pulse width of the voltage applied to the recording electrode so as to increase a pulse width of the voltage applied to the recording electrode. 4. A supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for discharging toward the medium; a target pixel of the same recording electrode is a recording pixel; and if n of the m pixel groups before the target pixel are non-recording pixels, the recording electrode of the target pixel is And a pulse width control means for controlling the pulse width of the voltage applied to the recording electrode so as to shorten the pulse width of the voltage applied to the ink jet recording apparatus. 5. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. By forming an electric field between the recording electrode and the recording medium, an electric field forming means for discharging colorant particles in the ink supplied to the recording electrode by the supply means toward the recording medium, An electric field applying unit that changes the electric field between the recording electrode and the recording medium so that the ink is not ejected; and a change in the electric field between the recording electrode and the recording medium provided by the electric field applying unit. And an electric field control unit for controlling the electric field according to an image recording pattern. 6. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. Electric field applying means for giving a change in the electric field to such an extent that the electric field does not change, and electric field control means for controlling a change in the electric field between the recording electrode and the recording medium given by the electric field applying means in accordance with a recording pattern of an image, An ink jet recording apparatus characterized by comprising. 7. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. An electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, and if n of the m pixel groups before the target pixel are non-recording pixels, the target pixel Recording cycle Electric field control means for controlling a change in an electric field between the recording electrode and the recording medium provided by the electric field applying means, so as to reduce a rate of occurrence of a strong electric field in the direction of the recording medium due to the change in the electric field. An ink jet recording apparatus comprising: 8. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. An electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, and if n of the m pixel groups before the target pixel are non-recording pixels, the target pixel Record in the recording cycle of An electric field control means for controlling a change in an electric field between the recording electrode and the recording medium provided by the electric field applying means so as not to generate a strong electric field in a medium direction; Recording device. 9. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. An electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, and if n of the m pixel groups before the target pixel are non-recording pixels, the target pixel Recording cycle Electric field control means for controlling a change in an electric field between the recording electrode and the recording medium provided by the electric field applying means so as to lengthen a cycle in which a strong electric field in the direction of the recording medium is generated. An ink jet recording apparatus characterized by the above-mentioned. 10. A supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. An electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, and if n of the m pixel groups before the target pixel are non-recording pixels, the target pixel Recording cycle Electric field control means for controlling a change in an electric field between the recording electrode and the recording medium provided by the electric field applying means so as to shorten a time in which a strong electric field in the direction of the recording medium is generated. An ink jet recording apparatus characterized by the above-mentioned. 11. A supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. Electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, n of the m pixel groups before the target pixel are non-recording pixels, Record after a certain number When there is a pixel, the distance between the recording electrode and the recording medium provided by the electric field applying means is increased so as to increase the rate at which a strong electric field is generated in the recording medium direction due to a change in the electric field in the recording cycle of the target pixel. An ink jet recording apparatus, comprising: electric field control means for controlling a change in an electric field. 12. A supply means for supplying an ink obtained by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. Electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, n of the m pixel groups before the target pixel are non-recording pixels, Record after a certain number When there is a pixel, a change in the electric field between the recording electrode and the recording medium given by the electric field applying means is set so as to shorten a period in which a strong electric field in the recording medium direction in the recording cycle of the target pixel is generated. An ink jet recording apparatus, comprising: an electric field control means for controlling. 13. A supply means for supplying ink formed by dispersing charged colorant particles in an insulating liquid to a recording electrode provided opposite to a recording medium, and according to an image signal to be recorded. An electric field is formed between the recording electrode and the recording medium by applying a pulse-like voltage to the recording electrode, and the colorant particles in the ink supplied to the recording electrode by the supply unit are recorded. An electric field forming means for ejecting the ink toward a medium; and applying a pulse-like voltage having substantially the same voltage as that for ejecting the ink to the recording electrode, whereby the ink is ejected between the recording electrode and the recording medium. Electric field applying means for giving a change in electric field to such an extent that the target pixel of the same recording electrode is a non-recording pixel, n of the m pixel groups before the target pixel are non-recording pixels, Record after a certain number When there is a pixel, a change in the electric field between the recording electrode and the recording medium given by the electric field applying means is set so as to lengthen a time in which a strong electric field in the recording medium direction in the recording cycle of the target pixel is generated. An ink jet recording apparatus, comprising: an electric field control means for controlling.