JPH0692006A - Image recording method and apparatus - Google Patents

Abstract

PURPOSE:To form a pixel by ink without using a nozzle for discharging ink, by supplying the ink to an ink holding area of an image carrier, forming a latent image in the ink holding area and transferring the ink of the latent image to a to-be-recorded material. CONSTITUTION:An ink feed part 5, an electric charge feed part 6 and a transfer part 7 are provided along the outer periphery of a drum 1. On the other hand, a pattern corresponding to an ink holding area is formed in an ink retainer layer 2 on the surface of the drum 1 by a pattern forming part 11. The ink supplied from the ink feed part 5 to the ink retainer layer 2 is held in the ink holding area first. Subsequently, electric charges based on image signals are supplied to the held ink from the charge feed part 6, whereby a latent image is formed. Then, only the ink to which the electric charges are supplied is selected and transferred to a to-be-recorded medium 8 by the transfer part 7. The remaining ink is collected by an ink collecting part 12, and the charges of the ink retainer layer 2 are removed by a charge removing means 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording method and an image recording apparatus for recording an image on a recording medium such as plain paper or a plastic sheet using ink, which is different from conventional ink jet and thermal transfer. The present invention relates to an improved image recording method and image recording apparatus.

[0002]

2. Description of the Related Art Ink jet recording and thermal transfer recording have been known as a device for recording an image on a recording medium such as paper.

In the ink jet recording method, ink droplets are ejected from fine nozzles to selectively form pixels by the ink droplets on a recording medium to obtain a desired image. This recording method is advantageous in that it is economical because it is possible to form pixels by ejecting ink only where it is needed. However, due to the use of a nozzle with a small diameter corresponding to the size of the ink droplets to be generated,
For example, the nozzle is often clogged due to the drying of ink in the nozzle, the precipitation of impurities, and the like.
In particular, in a line type head in which a plurality of nozzles are arranged in correspondence with the width of the recording paper, it is difficult to solve the problem of clogging, and thus it is difficult to realize.

On the other hand, in the thermal transfer recording method, an ink ribbon having a constitution in which a heat-melting or heat-subliming ink is applied to a support made of, for example, a polyester film, is formed on the ink ribbon by a thermal head or the like. The ink is transferred to the recording medium by selectively applying heat energy. This thermal transfer recording method has an advantage that an image with relatively high contrast and rich gradation can be obtained. However, this ink ribbon cannot be used repeatedly, and after recording, the ink left unrecorded and the support coated with this ink are discarded, which is not economical.

[0005]

In the conventional ink jet recording, there is a drawback that the nozzle is clogged and the reliability is inferior. On the other hand, in the thermal transfer recording, the use efficiency of the ink ribbon is poor and the running cost is high. there were.

The present invention has been made in view of the above problems, and a first object thereof is to provide means for forming a pixel by ink to obtain a recorded image without using a nozzle for ejecting ink. Especially.

A second object of the present invention is to provide an image recording apparatus capable of obtaining an image with high contrast and rich gradation by efficiently using ink and an ink holder without using an ink ribbon. .

[0008]

According to a first aspect of the present invention, an image carrier having an ink holding region having a predetermined pattern formed on the surface thereof, and an ink being held in the ink holding region on the image carrier. A means for supplying, a means for selectively causing a potential difference in the ink held in the ink holding area according to an image signal to form a latent image in the ink holding area, and the latent image. Provided is an image recording apparatus comprising a unit for transferring ink to a recording material.

Further, according to a second aspect of the present invention, an ink holding region having a conductive layer and a photoconductive layer laminated on the conductive layer, and having a predetermined pattern is formed in the photoconductive layer. Image carrier, means for supplying ink to the ink holding area, means for supplying substantially uniform charge to the ink held in the ink holding area, and the photoconductive layer according to an image signal. Means for forming a latent image based on the potential difference of the ink in the ink holding area by selectively irradiating the charge holding ink by reducing the resistance of the photoconductive layer. And an image recording apparatus comprising means for transferring the latent image-formed ink onto a recording material.

With the device according to the second aspect,
Using a laminate of a conductive layer and a photoconductive layer as an image carrier,
By applying uniform charge to the ink in advance and then irradiating the photoconductive layer with light to reduce the resistance of the photoconductive layer, the charge can be selectively attenuated from the ink holding the charge.

According to a third aspect of the present invention, a step of supplying ink to an ink holding area having a predetermined pattern formed on an image carrier, the ink held in the ink holding area is provided with an image signal. An image recording method comprising: a step of forming a latent image in the ink holding area by generating a potential difference in accordance with the potential difference; and a step of transferring the latent image-formed ink to a recording material. I will provide a. The method according to the third aspect of the present invention can be performed using, for example, the apparatus according to the first aspect of the present invention.

The potential difference means that the transfer operation at the time of transfer can be differentiated according to this potential difference. Examples of such a potential difference include a potential difference due to electric energy, a temperature difference due to thermal energy, and a difference in molecular binding force due to chemical energy. Further, it is possible to use a plurality of these potential differences together.

[0013]

In the present invention, after such a potential difference is generated, the ink is transferred to the recording medium by utilizing this potential difference between the holder and the recording medium. For example, when applying the potential difference as the potential difference,
The transfer unit that applies an electrostatic force or the like can transfer the ink to the recording medium by utilizing the potential difference of the ink. In this way, a selective potential difference is generated in the ink in the ink holding area based on the image signal to form an ink latent image, and the obtained ink latent image is transferred by utilizing this potential difference. With such a device, it is easy to transfer the desired ink to the recording medium. Further, according to the present invention, in forming ink pixels,
Since nozzles for ejecting ink are not required, there is no concern that the nozzles will be clogged, as seen in inkjet recording.

Further, according to the present invention, the image carrier can be circulated so that the once used carrier can be used any number of times. In addition, by reusing the ink that has not been transferred and remains on the image carrier, it is possible to effectively use the carrier and the ink. It is also possible to collect the residual ink once and reuse it. Further, even if the ink is not collected, the image carrier is divided into a region excellent in ink retention and a region inferior in ink retention, and therefore ink is further supplied onto the image carrier with ink remaining. However, the supplied ink can be sufficiently retained in the area excellent in ink retention. Since the image carrier can be repeatedly used in this manner and the liquid ink can be used as in the conventional ink jet recording, it is possible to provide an image recording apparatus having a lower running cost than thermal transfer recording using an ink ribbon. You can

[0015]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a view showing the schematic arrangement of an image recording apparatus according to the first aspect of the present invention. Ink supply section 5, charge supply section 6, transfer section 7 are provided along the outer circumference of cylindrical drum 1. Are arranged respectively. First, an outline of the overall operation will be described.

Driving force from a motor (not shown) or the like is transmitted to the central axis of the drum 1, and the drum 1 rotates in the direction of the arrow in the figure in accordance with a command from a CPU or the like (not shown). Drum 1
The image processing unit processes image signals of the CPU, the transmission system, the memory, and the like according to the rotation of the image forming unit, and the charge supply unit 6 is processed through the drive circuit.
To perform the operation of each part.

The surface of the drum 1 has an ink holding layer 2. As shown in FIG. 2A, the pattern forming section 11 provided on the drum 1 forms a pattern on the ink holding layer 2 corresponding to the ink holding region 3a having excellent ink holding ability. As a result, the ink holding layer 2 is divided into the ink holding area 3a and the area 3b having a poor ink holding property. The ink supplied onto the holding layer 2 is held in the ink holding region 3a due to the difference in the ink holding property of the holding layer 2 shortly or before reaching the charge supply unit described below. In FIG. 1, the ink holding area 2 is formed on the ink holding layer 2 by using the ink forming portion 11.
Although a is formed, the ink forming portion 11 can be omitted by applying the ink holding layer 2 in which the ink holding area 3a is formed in advance on the drum. Further, the formation of the ink holding area 3a using the ink forming portion 11 does not have to be performed for each image recording step, and the formed ink holding area 3a can be used any number of times.

Next, the charge supplying section 6 selectively supplies charges to the ink held in the ink holding area 3a based on the image signal. That is, the ink that has been separated and held in the plurality of regions of the ink holding layer 2 is divided into ink that has been supplied with electric charge and ink that has not been supplied with electric charge. In this way, a latent image is formed in the ink area.

Next, in the transfer section 7, only the ink supplied with the electric charge by the electric charge supply section 6 is selected from the inks held in the ink holding layer 2, and the plain paper or the plastic arranged oppositely is selected. The image is transferred onto a recording medium 8 such as a sheet.

After the transfer, for example, the ink collecting section 12 collects the remaining ink. However, if there is no change in the formed pattern and the pattern is reused, it is not necessary to operate the ink recovery unit 12. Even if the residual ink is not collected, the ink retaining layer is divided into the region 3a having excellent ink retaining property and the region 3b having poor ink retaining property. Even if the ink is supplied onto the holding layer 2, the ink can be held substantially uniformly over the entire region 3a having excellent ink holding properties. Next, the ink holding layer 2 is removed by the charge removing unit 10.
To remove the electricity.

As described above, by selecting the ink region based on the image signal by the charge supply unit 6 and supplying the charge, a recorded image based on the image signal can be obtained on the recording medium 8. Next, details of each unit will be described.

The ink holding layer 2 provided on the surface of the drum 1 has an ink holding area 3a formed by the pattern forming section 11.
Mainly has a function of separating and holding ink in a pixel shape. As shown in FIG. 2A, the ink holding layer 2 includes a region 3a having excellent ink holding property and a region 3 having poor ink holding property.
and b. In this figure, the regions 3a are regularly arranged vertically and horizontally. As such an ink holding layer 2, a polyester film having high water repellency can be used. A water-based ink is used as the ink. The polyester film is remarkably inferior in retainability to water-based ink. Therefore, the flat polyester film cannot hold the ink. However, the region 3a having excellent ink retention is obtained by partially providing fine irregularities or holes on the surface of the polyester film, and the ink retention is improved. That is, when ink is supplied to the ink holding layer 2, the ink cannot be held in the region 3b having poor ink holding property, and soon, the ink is aggregated on the surface of the region 3a having excellent ink holding property to form irregularities or holes on the surface. Retained.

The ink supply section 5 has a sponge-like roller 51 having a soft surface. The roller 51 is in contact with the ink holding layer 2 with an appropriate pressure while the inside of the sponge structure is impregnated with the ink 4. Then, the roller 51 rotates with the rotation of the drum 1, so that the liquid ink 4 is uniformly applied to the ink holding layer 2. When the area where the ink is applied leaves the roller 51 as the drum 1 rotates,
The ink is separated and held due to the difference in the ability of the ink holding layer 2 to hold the ink. FIG. 2A is a view showing a cross section of the ink holding layer 2 holding the ink 4 in this state.
The ink holding layer 2 is arranged in the charge supply unit 6 by the rotation of the drum 1 while keeping such a state.

FIG. 4 is an example showing a detailed configuration of the charge supply section 6. FIG. 4 is an example in which a potential difference is applied as the energy difference that contributes to the transfer operation. The charge supply unit 6 supplies charges to the ink region in order to generate this potential difference.
Further, in this example, negative-polarity ions are supplied as electric charges, and it is mainly composed of an ion generator and a pair of control electrodes for supplying ions.

Here, the dielectric layer 6 made of polyimide or the like is used.
An ion generating electrode 63 for generating ions is provided on one surface of 1. The induction electrode 62 is provided on the other surface.
AC voltage 6 is applied between the ion generating electrode 63 and the induction electrode 62.
When 5 is applied, positive and negative ions are generated in the vicinity of the ion generating electrode 63 due to the generation of the alternating electric field. However, due to the bias voltage 67 applied between the control electrode 66 disposed on the side of the control electrode pair closer to the ion generation electrode 63 and the ion generation electrode 63, only the negative ions 60 are directed toward the control electrode 66. Move to. Here, a signal voltage 69 is applied between the control electrode 66 and one control electrode 68 so as to move the ions to the control electrode 68 side, and the ions 60 are allowed to pass through. The signal voltage 69 at this time is set so that the potential of the control electrode 68 is equal to or slightly higher than that of the control electrode 66. The ions 60 that have passed through the pair of control electrodes 66 and 68 are accelerated by the voltage 64 and supplied in the direction of the arrow in the figure. On the other hand, when the ions are not supplied, the signal voltage 69 is set so that the potential of the control electrode 68 becomes lower than that of the control electrode 66, and the passage of the ions 60 is blocked.

Thus, the supply of ions, that is, charges, is
This is performed by turning on / off the signal voltage 69. FIG. 5 shows a block diagram from the input of the image signal to the charge supply unit 6. As shown in FIG. 5, an image signal output from a scanner, a video camera, or the like (not shown) or an image signal sent via a computer or a transmission line is converted in an image processing unit as needed, and sent to a drive circuit to generate a signal voltage 69. Control. It should be noted that this device can also perform gradation recording. FIG. 6 shows a block diagram from the input of the image signal to the charge supply unit 6 when performing gradation recording.

In FIGS. 5 and 6, the image signal or the gradation image signal is data obtained by A / D converting data from a scanner or a video camera, digital data from a computer or the like, data from various memories, and the like. It is possible.

The image processing unit is a block for converting an image signal or a gradation image signal as necessary, and for example, various filter processes such as a high pass filter and a low pass filter, a color conversion process, a density correction process, and a gradation process. Control processing and the like are performed.

The gradation control processing is processing for gradation recording, and sets the application time of the signal voltage 69 according to the data of the image signal, for example. The signal voltage 69 is controlled by the drive circuit based on the application time set here. The application time of the signal voltage 69 corresponds to the amount of charge supplied to the ink. FIG. 7 is a graph showing the relationship between the charge amount and the transfer amount to the transfer material. As shown in this graph, when the supplied charge amount does not reach Qt, a transferable potential difference cannot be obtained. For this reason, the ink does not rise or fly. However, when the charge amount becomes Qt or more,
The transfer amount of the charged ink in the holding region increases in accordance with the charge amount, and when it exceeds Qm, all the charged ink in the holding region is transferred, and the transfer amount becomes constant. Therefore, the application time may be controlled according to the image signal within the range of the charge amount of Qt to Qm. By controlling the application time in this manner, the amount of electric charge supplied can be easily controlled, and gradation recording can be easily performed.

On the other hand, unlike the above-mentioned example, when positive charges are supplied, the polarities and values of the signal voltage 69, the bias voltage 67, and the voltage 64 are appropriately changed in the same configuration. To be achieved. Regarding the charge supply means, Japanese Patent Application No. 02-518 filed by the present applicant.
32, etc., and can be variously modified and applied as the charge supply unit of the present invention.

8 and 9 are views for explaining the structure and operation of the transfer section 7. By applying an electric field in the transfer section 7, electrostatic force is applied to the ink,
It is transferred to the recording medium 8.

A transfer electrode 71 provided on a substrate 72 is provided on the back surface side of the recording medium 8 which is arranged facing the ink holding layer 2 with a gap. Ink holding layer 2
Between the back surface of the drum, that is, the drum 1 and the transfer electrode 71,
The transfer voltage 73 is applied. Regarding the magnitude of the transfer voltage 73, of the ink 4 held in the ink holding layer 2, the ink that has not been supplied with the charge in the charge supply unit 2 is not transferred and the charge is supplied by the charge supply unit 2. It is set so that only the ink is transferred to the recording medium 8.

In the transfer step, when the gap between the ink holding layer 2 and the recording medium 8 is relatively large, the ink is ejected to transfer. FIG. 8 is a schematic diagram showing a state of transfer performed by ejecting ink. As shown in FIG. 8, the transfer electric field generated by the transfer voltage 73 causes an electrostatic force to act on the ink 4 held in the ink holding layer 2, and the charge is supplied in the charge supply unit 6 by the electrostatic force. The ink 41 flies toward the recording medium 8 and the transfer is performed. The ink 42 that has reached the recording medium side forms an ink image point by permeating on the surface of the recording medium 8 or inside.
On the other hand, the ink 43 that has not been supplied with the charge in the charge supply unit 6 passes through the transfer unit 7 as the residual ink while being held in the ink holding layer 2.

When the gap between the ink holding layer 2 and the recording medium 8 is relatively small, the ink is raised to transfer. FIG. 9 is a schematic diagram showing the state of transfer performed by raising the ink. As shown in FIG. 9, the transfer electric field formed by the transfer voltage 73 causes an electrostatic force to act on the ink held in the ink holding layer 2, and the static electricity causes the ink charged with the charge supply unit 6 to be covered. The recording medium 8 is raised in the direction of the recording medium 8 and thus transferred. In this case, when the raised ink 44 reaches the surface of the recording medium 8, the ink retaining layer 2 is more excellent in retaining the ink in the recording medium 8 than the ink retaining layer 2 is retaining the ink. And the ink image points 45 are formed on the recording medium 8 in the same manner as shown in FIG.

When the ink is raised and transferred to the recording medium 8, there is an advantage that the transfer operation can be performed with a relatively low transfer voltage. However, on the other hand, it is necessary to set the gap between the ink holding layer 2 and the recording medium 8 so that the ink comes into contact with the recording medium only when the ink rises.

On the other hand, when the ink is ejected and transferred to the recording medium 8, only the ink which is separated from the ink holding layer 2 and is ejected is transferred. Therefore, the transfer voltage defined by whether or not the ink is ejected is applied. If it is set, the minimum transfer operation can be guaranteed, so the stability against noise is relatively large.

As described above, the ink to which the electric charge is selectively supplied based on the image signal in the electric charge supplying section 2 is transferred to the recording medium 8, and the recorded image by the ink based on the image signal is obtained. It should be noted that this transfer voltage may be applied at a constant voltage during the operation of transferring the ink to the recording medium.

Further, the recording medium 8 is arranged on the transfer portion by the following operation. That is, in FIG. 1, the recording medium 8 is sent to the transfer unit 7 at the same timing as the rotation of the drum 1 by a carrying means having carrying rollers 91, 93 and the like which are rotated by a driving force such as a motor (not shown). Normally, a sensor including a pair of light emitting element 95 and light receiving element 96 is provided immediately before the transfer section 7 to detect the intrusion of the recording medium 8. By making the recording medium stand by at this position, the timing is controlled so that the position of the ink to be transferred on the drum and the position of the recording medium to be transferred coincide with each other. The recording medium is conveyed to the transfer portion by driving the conveying roller 91 at such timing. Furthermore, since the transfer operation is normally performed continuously, the recording medium is continuously conveyed at a speed proportional to the rotation speed of the drum 1. On the other hand, the recording medium 8 that has completed the transfer operation is ejected by the transport roller 93 provided on the exit side.

When the drum 1 is further rotated, the area of the ink holding layer 2 which has passed through the transfer section 7 is destaticized by the destaticizing means 10 and is then placed again on the ink supply section 5. At this time, the ink remaining on the ink holding layer 2 without being transferred to the recording medium 8 in the transfer section 7 (ink 43 in FIG. 8).
Alternatively, the ink 46) in FIG. 9 is used in the ink supply unit 5 in the next recording operation together with the ink stored therein. In this way, the ink holding layer 2
By circulating the above, the holding layer 2 itself can be repeatedly used. Along with this, it is possible to use the residual ink without wasting it. These advantages are particularly remarkable when the number of contact members for the holding layer 2 is reduced as much as possible and the holding layer 2 is not deteriorated due to wear or damage.

By the way, the area of the ink holding layer 2 having excellent ink holding ability and the area of poor ink holding ability can be obtained as follows. That is, thermal energy is partially applied to a portion where an area having excellent ink holding property is provided, so that at least the surface is partially contracted, or a release agent such as a fluororesin which is previously uniformly coated. It is obtained by removing the conductive material. Further, instead of giving mechanical deformation, modification of surface property by heat or light irradiation can be utilized.

Since the holder using the heat method can be manufactured with a relatively simple structure, the manufacturing method will be described below. FIG. 10 is a diagram showing an outline of an apparatus in which a region having an excellent ink retaining property is provided in a partial region of the holder 21 made of a polyester sheet. In this structure, the polyester sheet 21 is interposed between the platen 31 formed of a rubber roller on a cylinder and the thermal head 32, and the polyester sheet 21 is wound from the supply roll 34 to the winding roll 35 while urging the polyester sheet 21 with a predetermined pressure. Side to side at a constant speed. A plurality of heating elements 33 are arranged in the thermal head in the depth direction of the drawing. In this thermal head, the heating element 33 is selectively driven by an external signal based on a drive circuit (not shown), and heat energy is applied to the polyester sheet surface. As the thermal head 32, one having the same structure as that used as a recording unit of a general facsimile apparatus can be used. The position of the ink holding layer 21 which should be a region having excellent ink holding property is the heating element 3
When the position of 3 is reached, the thermal head is driven to 300 ° C.
The heat generation energy of a certain degree is applied to the ink holding layer 21.
The ink holding layer 21 causes heat shrinkage or the like in the heat pattern portion provided by the thermal head 32. Thereby, the ink holding property is improved, and an ink holding layer having a region having poor ink holding property and a region having excellent ink holding property is obtained. By such a procedure, the pattern of the ink holding area can be regularly provided in a two-dimensional manner.
The ink holding layer 2 shown in can be manufactured. Further, in order to form the holding layer 2 into the cylindrical shape shown in FIG. 1,
It can be obtained by cutting it into an appropriate size as necessary and pasting it on the peripheral surface of the drum 1 with an adhesive or the like. The thickness of the ink holding layer applied to the present invention is not particularly specified, but in the polyester sheet applied in the configuration of FIG. 7 described above, it is taken into consideration from the degree of freedom in handling during transportation and attachment to the drum. Thickness of 50μm to 200μm
Those having a thickness of about 100 μm are most suitable.

Further, the heating element 33 of the thermal head 32 is used.
It is also possible to arrange the regions having excellent ink retaining properties in, for example, a zigzag pattern by controlling the driving timing of. An example of the pattern thus obtained is shown in FIG. 3A. Further, the shape of each pattern constituent element in the ink holding area on the ink holding layer does not necessarily have to be circular, and various shapes such as an ellipse, a rectangle, and a rhombus can be used. Such an example is shown in FIGS. 3B and 3C.

It should be noted that it is not always necessary to regularly arrange the regions having excellent ink retaining properties. It is possible to obtain a desired area pattern on the holding layer 2 by controlling the signal for driving the thermal head based on an image signal or the like.

Further, it is not always necessary to make one pattern constituent element correspond to one image point of an image to be formed.
When a plurality of pattern constituent elements are associated with one image point, even if some of the plurality of pattern constituent elements are not sufficiently transferred, a large defect does not occur in the image.

The image carrier used in the present invention has an ink holding region formed on the surface of the image carrier. For this reason, the surface of the image carrier is divided into an ink holding region having excellent holding properties for the ink used and other regions, that is, regions having poor ink holding properties.

The ink holding region is obtained, for example, by forming an ink holding layer on the surface of the base of the image carrier and subjecting it to heat processing or treatment in a predetermined pattern. In addition, various metals can be obtained by providing a predetermined pattern on a substance having poor ink retention by means such as vacuum deposition, electroplating, and electroless plating. Alternatively, a region having excellent retention may be used as a base, and a region having poor retention may be provided in the partial region. In this case, for example, a method of partially coating various release agents by means such as spraying can be used.

The material of the ink holding layer is selected by paying attention to the following points. The main function of the ink holding layer is to separate and hold the ink in a predetermined pattern. It is preferable that ink loss due to the influence of the holding layer is minimized. Therefore, a material that does not allow ink to penetrate is suitable. Further, it is suitable to use a material that does not cause deterioration such as erosion caused by contact with ink as much as possible. Further, it is preferable that the charge supplied to the ink does not escape. For this reason, it is suitable that the conductivity with respect to the ink is relatively small and that it is substantially insulating.

Examples of such materials include a polyester film such as polyethylene terephthalate, a fluororesin such as polytetrafluoroethylene, a heat resistant polymer such as polyimide, a silicone resin, and a polycarbonate.

The ink used in the present invention is sufficiently retained in a region having an excellent ink retaining property, a potential difference is selectively imparted to the ink region, and a latent image is formed based on this potential difference. A material that can transfer the ink to the recording medium is selected. As inks having such characteristics, water-based inks, oil-based inks, neutral inks, and the like can be used, and even solid inks at room temperature can be used. Below, the modification of the 1st aspect of this invention is demonstrated. FIG. 11 is a diagram showing a schematic configuration of an image recording apparatus according to a modified example of the first aspect of the present invention. The major difference from the above-mentioned embodiment is that
The point is that two charge supply units are provided as the potential difference generating means.

To explain the outline of the operation of this modified example, the ink 4 is supplied to the ink holding layer 2 in the ink supply section 5 as in the operation of FIG. The ink 4 is held in a region of the holder having excellent ink holding properties, reaches the first charge supply unit 601, and is uniformly supplied with charges. The charges supplied here are negative ions, and the ink 4 on the ink holding layer 2 is all negatively charged. Next, in the second charge supply unit 602, charges are selectively supplied to the ink area based on the image signal. The charges supplied here are positive ions and selectively cancel or at least weaken the ink charged by the first charge supply unit 601. In this way, the charge given by the first charge supplying unit 601 is stored in the ink region where the charge is not removed by the second charge supplying unit 602, and a latent image is formed in the ink holding region. . The ink is sent to the transfer unit 7 in this state. In the transfer section 7, the ink having the electric charge is selectively transferred to the recording medium 8 as in the previous embodiment. Therefore, the ink region to which the electric charge is selectively supplied in the second electric charge supplying section 602 is not transferred to the recording medium 8, and is obtained by processing the image signal in advance.
The second charge supply unit 602 is driven based on the image signal of so-called negative information.

As described above, the potential difference is selectively generated in the ink regions in the first and second charge supply portions,
A recorded image with ink is obtained on the recording medium according to the potential difference.

With such a configuration, the first
Even if some of the inks hold electric charges as noise before reaching the electric charge supply section of
Since the electric charge is uniformly supplied in the electric charge supplying section, there is an advantage that noise can be removed.

Here, the configuration shown in FIG. 4 can be applied to both of the two charge supply units 601 and 602 by appropriately changing the polarity of the applied voltage and the like. Since it is not necessary to selectively supply the toner, a general corona charger used in a copying machine or the like can be used.

It is also possible to change the arrangement of the first charge supply section 601 and the second charge supply section 602.
In this case, first, the second charge supply unit 602 selectively supplies the charge to the ink according to the image signal, and then the first charge supply unit 601 spreads the second charge over the entire ink in the ink holding region. By supplying a charge having a polarity opposite to that of the supply portion 602, the already supplied charge may be canceled and a new charge may be supplied to another region.
Even in this case, as a result, a potential difference similar to that described above can be generated, and a recorded image can be obtained at the transfer portion. Next, still another modification of the first aspect of the present invention will be described.

FIG. 12 is a view showing the schematic arrangement of an image recording apparatus according to another modification of the first aspect of the present invention. Similar to the previous modification, the ink supplied to the ink holding layer 2 in the ink supply unit 5 has the same charge supply unit 603 as that of the second charge supply unit 602 in the second embodiment.
The positive polarity electric charge is selectively supplied to the image signal. Here, the image signal used for selecting the ink region is processed as used in the other modification of the present invention. That is, it is an image signal of negative information.

After that, the ink to which the electric charge is selectively supplied in the first transfer portion 710 is removed from the ink holding layer. The residual ink 48 that is not removed here and is still held in the ink holding layer is sent to the second transfer unit 720.
At the second transfer portion, the residual ink 48 is transferred onto the recording medium 8 to form recording image points 49, and a recorded image is obtained.

FIG. 13 is a diagram showing a detailed structure of the first transfer portion 710. The drum 711 also serves as a transfer electrode whose outer periphery is covered with a resin 712 having an insulating property. That is, the ink latent image having a positive charge held in the holding layer 2 is the voltage 714 applied to the drum 711.
Is transferred to the drum 711 side by the negative potential generated by the, and unnecessary ink is removed. The transfer operation is performed in the same manner as the transfer unit 7 described above. Also,
The drum 711 is rotated by a driving unit such as a motor (not shown), and the transferred ink is collected by a sponge-like ink collecting pad 713.

A transfer roller 721 is attached to the second transfer portion 720.
Therefore, the transfer roller 721 and the drum 1 are arranged so as to be added with a predetermined pressure via the recording medium 8. The transfer roller 721 is a rubber roller made of silicone rubber or the like and does not have its own power and rotates with the rotation of the drum 1. Here, when the residual ink 48 that has passed through the first transfer portion 710 reaches the second transfer portion 720,
The recording medium 8 provided by the same transporting means as in FIG. 1 is transported to the second transfer portion 720. Then, the recording medium 8 comes into contact with the ink held on the drum 2, and the ink is transferred to the recording medium 8 side to obtain a recorded image.

In such a structure, since the transfer to the recording medium is performed by contacting with the ink holding layer, the predetermined pressure contact force can be used in addition to the adhesive force of the ink itself to transfer the ink. There is an advantage that various transfer can be easily performed.

In the three types of apparatus according to the first aspect of the present invention described above, the case where the ink holding layer is consistently arranged on the peripheral surface of the drum is described, but the shape of the ink holding layer is The shape is not limited to the cylindrical shape, and may be a sheet shape or an endless belt shape.

When a sheet-shaped ink holding layer is used, it may be provided with a feeding means for appropriately feeding the sheet-shaped ink holding layer to each part, and by further arranging the feeding path to circulate. The ink holding layer and the ink can be effectively used. Further, in order to facilitate the transportation of the sheet-shaped ink holding layer, an auxiliary material may be provided on the back surface of the ink holding layer.

On the other hand, when an endless belt-shaped ink holding layer is used, it is suitable to circulate and use the ink holding layer as in the above-described embodiment using the drum, and further, the shape of the apparatus is changed. It has the effect of giving a degree of freedom. less than,
An example of the second aspect of the present invention will be described.

In the above-mentioned example, the charge supply section for generating ions is used to generate the potential difference as the potential difference. The charge supply section can directly apply ions to the ink and selectively supply the charge according to an image signal. On the other hand, in the following apparatus, a laminated body of a conductive layer and a photoconductive layer laminated on the conductive layer is used as an image carrier, which is uniformly charged and then selected according to an image signal. By selectively irradiating light, the resistance of the photoconductive layer is selectively lowered, and the charge is selectively attenuated from the uniformly charged ink. In this apparatus, the light irradiation indirectly leaks the charges in the ink in the uniformly charged ink holding area through the photoconductive layer, and generates a potential difference depending on the presence or absence of the light irradiation. FIG. 14: is a figure which shows an example of the apparatus concerning the 2nd aspect of this invention.

In this apparatus, the ink supply unit 5, the charge supply unit 52, and the light irradiation unit 53 are provided along the outer circumference of the cylindrical drum 1 having the conductive layer 54 and the photoconductive layer 55 formed on the conductive layer 54. , And the transfer section 7 are arranged respectively.

To explain the outline of the operation of this apparatus, the ink 4 is supplied to the ink holding layer 2 in the ink supply section 5 as in the operation of FIG. The ink 4 is held in a region of the holder having excellent ink holding properties, reaches the first charge supply unit 601, and is uniformly supplied with charges. In this device, next, in the light irradiation section 53, an ink area is selected based on the image signal and light is irradiated to the photoconductive layer 55 from the inside of the drum. Photoconductive layer 55 irradiated with light
Has a low resistance and is in a conductive state, so that the charges held in the ink move to the conductive layer 54 through the portion where the ink and the photoconductive layer 55 are in contact with each other. In this way, the charge of the ink above the photoconductive layer irradiated with light is erased,
A potential difference occurs. Due to this potential difference, a latent image of ink corresponding to the image signal is formed in the ink holding area. The ink on which the latent image is formed is then sent to the transfer section 7, and the transfer section 7 selectively transfers the charged ink to the recording medium 8. The ink whose electric charge is selectively erased in the light irradiation section 53 is not transferred to the recording medium 8, so that the light irradiation section 53 is driven based on an image signal of so-called negative information obtained by previously processing the image signal. To be done.

Next, the latent image formation by light irradiation will be further described. FIG. 15A shows a cross-sectional view of the drum 2 with the ink droplets 1 attached. The drum 1 has a conductive layer 54 on the back surface.
And the ink holding layer 202 made of a substance having an excellent ink holding property is formed in a pattern corresponding to pixels on the surface of the photoconductive layer 55. An ink droplet 49 having a charge is held inside. A support layer (not shown) may be laminated on the back surface of the conductive layer 54. When light 56 is selectively emitted from the light source 53 to the ink droplet 49 of FIG. 15A according to the image signal, the irradiated portion 5 of the photoconductive layer 55 is irradiated.
Since 7 has a low resistance and is in a conductive state, the charge held in the ink droplet 49 is transferred to the ink droplet 49 and the photoconductive layer 55.
Move to the conductive layer 54 through the portion in contact with. FIG. 15B is a schematic diagram showing how the charges of the ink 49 are moved by this light irradiation, and FIG. 15C is a diagram showing how the charges of the ink 49 are erased by the movement of the charges. As shown in FIG. 15B, the ink 49 to which the electric charges have been transferred has the electric charges erased from inside as shown in FIG. 15C. . In this way, only the ink droplet 1 irradiated with light loses the electric charge, and an electrostatic image can be formed.

Since the back surface of the drum 1 is exposed in FIG. 15B, the conductive layer 54 needs to be light-transmissive. When a support is laminated on the back surface of the conductive layer 54, a light-transmitting substance is used as the support.

The pattern of the ink holding layer 202 used in FIGS. 15A to 15C is the same as the pattern shown in FIG. In this example, circular pattern components are arranged at substantially equal intervals. (Fig. 1
6) However, the size of the circular pattern component may be any size, thickness and shape as long as it can maintain the surface tension to the extent that the ink droplets 202 are not separated in the ink holding layer 49. Good. Further, the interval can be appropriately changed according to the characteristics required for the image, such as the resolution and the sharpness. Further, it is possible to make a plurality of pattern constituent elements correspond to one stroke point of an image to be formed.

FIG. 17 shows a modification of the pattern of the ink holding layer shown in FIG. Further, FIG. 18 shows a state of charge transfer when the ink holding layer shown in FIG. 17 is used. Figure 1
5A to 15C, the ink holding layer 49 shown in FIG.
As shown in FIG. 17, when the opening 203 is provided inside the ink holding layer,
As shown in FIG. 18, the ink droplet 202 and the photoconductive layer 55.
The area in contact with is increased, and the charge transfer during light irradiation is smoothly performed. The openings 203 may have any size and shape, or a plurality of openings may be provided as long as the surface tension that does not separate the ink droplets 202 can be maintained in one ink holding layer 49.

FIG. 19 shows the drum 1 for the ink droplet 49.
This is an example of irradiating the light 56 from the surface. In this case, the conductive layer 54 on the back surface of the photoconductive layer 55 needs to be a non-translucent substance so that the light 56 is not transmitted. In addition, the type of ink and the wavelength of light must be selected in advance so that the ink droplet 49 transmits the incident light 56. In the example of FIG. 19, when the light 56 is applied from the surface of the drum 1, the light 5 is applied only to a portion corresponding to the periphery of the ink holding layer 202 in the photoconductive layer 55.
Since 6 is reached, the range in which the charges move is narrowed. Particularly in such a case, it is preferable to form the pattern as shown in FIG. 17 in order to secure the area of charge transfer.

[0072]

As described above, according to the present invention, a recorded image can be obtained without using a nozzle for forming an ink pixel, and the ink can be selectively transferred onto a recording medium. An economical image recording method and image recording apparatus can be provided. Further, by circulating the ink holding layer that holds the ink in a drum shape or a belt shape, the ink holding layer and the ink can be effectively used.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an image recording apparatus according to an example of a first aspect of the present invention.

FIG. 2 is a schematic view of an ink holding layer used in the image recording apparatus of the present invention.

FIG. 3 is a diagram showing another example of an ink holding layer.

FIG. 4 is a diagram for explaining the operation of a charge supply unit.

FIG. 5 is a block diagram showing a process of processing an image signal.

FIG. 6 is a block diagram showing a processing step of a gradation image signal.

FIG. 7 is a graph showing the relationship between the amount of charge supplied to ink and the amount of transfer to a transfer material.

FIG. 8 is a diagram for explaining the operation of the transfer unit.

FIG. 9 is a diagram for explaining another operation of the transfer unit.

FIG. 10 is a schematic configuration diagram showing an example of an apparatus for producing an ink holding layer.

FIG. 11 is a schematic configuration diagram showing a modified example of the image recording apparatus according to the first aspect of the present invention.

FIG. 12 is a schematic configuration diagram showing another modified example of the image recording apparatus according to the first aspect of the present invention.

FIG. 13 is a diagram for explaining the operation of the transfer unit in FIG.

FIG. 14 is a diagram showing an example of an image forming apparatus according to a second aspect of the present invention.

FIG. 15 is a diagram showing an example of how a potential difference is generated by light irradiation.

16 is a diagram showing an example of an ink holding layer used in FIG.

FIG. 17 is a diagram showing another example of the ink holding layer used in FIG.

FIG. 18 is a diagram showing another example of how a potential difference is formed by light irradiation.

FIG. 19 is a diagram showing still another example of how a potential difference is formed by light irradiation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Drum 2 ... Ink retention layer 3a ... Area with excellent ink retention 3b ... Area with poor ink retention 4 ... Ink 5 ... Ink supply section 6 ... Charge supply section 7 ... Transfer section 8 ... Recording medium

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication location B41J 27/00 Z 9211-2C 27/18 9211-2C H04N 1/034 8721-5C (72) Invention Person Koichi Ishii 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Research and Development Center

Claims (3)

[Claims] 1. A step of supplying ink to an ink holding region having a predetermined pattern formed on an image carrier, and causing a potential difference in the ink held in the ink holding region according to an image signal. Accordingly, the image recording method comprises: a step of forming a latent image in the ink holding area; and a step of transferring the latent imaged ink to a recording material. 2. An image carrier having an ink holding area having a predetermined pattern formed on its surface, means for supplying ink to the ink holding area on the image carrier, and ink held in the ink holding area. And a means for selectively generating a potential difference according to an image signal to form a latent image in the ink holding area, and a means for transferring the latent imaged ink onto a recording material. Image recording device. 3. An image carrier having a conductive layer and a photoconductive layer laminated on the conductive layer, wherein the photoconductive layer is provided with an ink holding region having a predetermined pattern, and the ink holding region. Means for supplying ink to the ink, means for supplying a substantially uniform charge to the ink held in the ink holding region,
In response to an image signal, the photoconductive layer is irradiated with light to lower the resistance of the photoconductive layer, thereby selectively attenuating the charge from the ink that retains the charge, and reducing the ink in the ink holding region. An image recording apparatus comprising: a unit that forms a latent image based on a potential difference; and a unit that transfers the latent image-formed ink to a recording material.