JPH08216388A - Image forming device, image forming method and image formed matter - Google Patents

Abstract

PURPOSE: To reduce the warping of printing medium after the formation of an image by a method wherein the ratio of the total sum of ink and a printability improving liquid to the total amount of ink, which is discharged to all the picture elements of a printing medium, is controlled by controlling the discharging of the printability improving liquid. CONSTITUTION: The total sum of the amount of ink and the amount of a printability improving liquid, both of which are discharged to a printing medium 10 is calculated by a CPU. On the basis of the ratio (or printing density) of the total sum of ink and the printability improving liquid given to the printing medium to the total amount of ink for all the picture elements and the amount of warpage of the printing medium, the discharge of the printability improving liquid is calculated by the CPU and the discharging position is also determined. On the basis of the result, the printability improving liquid and the ink are discharged to the printing medium from heads 9A, 9B, 9C, 9D and 9E in order to form image on the printing medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus capable of printing a high-quality image on a print medium, an image forming method and the obtained image formed product, and more specifically, to wrinkles (wrinkles) on the print medium. ) And an image forming technique capable of reducing warpage.

The present invention is applicable to paper, woven cloth, non-woven cloth, textile products, O
The present invention can be applied to all devices that use print media such as HP paper and leather, and specific applicable devices include office equipment such as printers, copiers and facsimiles, and industrial mass production equipment.

[0003]

2. Description of the Related Art Ink jet recording methods are used in printers, copying machines, facsimiles and the like because of their low noise, low running cost, easy downsizing of devices, and easy colorization.

Generally, the color ink jet printing method is a method of performing color recording using three colors of cyan, magenta, and yellow, or four colors of ink with black added. By the way, when the inkjet recording method is applied to a color recording apparatus, in order to obtain a color image with high colorability without ink bleeding, it is necessary to use a special paper that has been treated to prevent bleeding. . However, in recent years, those having printability on plain paper have been put into practical use by improving the ink. However, there is still room for improvement in the printing quality.

Further, the ink used in conventional ink jet recording generally contains water as a main component, and water is added to the ink to prevent drying.
It is common to contain a water-soluble high-boiling solvent such as glycol for the purpose of preventing clogging, and when recording on plain paper using such an ink, sufficient fixability cannot be obtained. In addition, there is a problem in that a non-uniform image is generated, which is presumed to be due to the non-uniform distribution of the filler and the sizing agent on the recording paper surface.

In particular, when a color image is to be obtained, the inks of a plurality of colors are superposed one upon another before being fixed on the paper, so that the color bleeds or becomes uneven at the boundary portion of the different color images. Sometimes they were mixed and a satisfactory image was not obtained.

Therefore, in order to solve the above problems, a method of applying a treatment liquid onto a print medium is known. For example, in JP-A-5-202328, an ink composition containing at least one chemical dye agent having at least one carboxyl group and a polyvalent metal salt solution are used, and the polyvalent metal salt solution is applied to a print medium. Later, a method of applying an ink composition to obtain a good image is disclosed.

[0008]

In the ink jet printing method, since an ink containing water as a main component is applied to a print medium for recording, the print medium absorbs the ink to elongate the print medium to cause wrinkles. appear. Further, the water is evaporated from the ink applied to the print medium, so that the warp occurs. Furthermore, since the elongation rate differs between the surface of the print medium on which the ink is applied and the back surface on which the ink is not applied, in the thickness direction of the print medium, warpage occurs.

FIG. 7 shows wrinkles and warpage of the print medium. In FIG. 7, the head 101 reciprocates in the direction of the arrow X in the drawing to eject ink droplets in the downward direction in the drawing and apply ink to the surface of the print medium 103 to form an image.

However, as described above, the print medium 103
By applying ink to the print medium 10,
_No. 3 is a wrinkle 102a that extends laterally and has a height in the Y direction of L ₁ .
Occurs, and water is evaporated from the ink applied to the print medium 103, so that a warp 102b having a horizontal height L ₂ is generated, and the print medium is in a deformed state as shown by 102. The portion of the print medium 102 facing the head 101 cannot be regulated by spurs, and thus such deformation is allowed.

In such a state of the print medium 102,
When the head 101 is further moved in the X direction to eject ink droplets to form an image on the print medium 102, the front surface (ink ejection port surface) 101 of the head 101 is ejected.
The predetermined distance L between the a and the print medium 103 is changed by L ₁ and L ₂ , so that the image quality is deteriorated and the front surface of the head and the print medium are rubbed with each other, and the end portion of the print medium is changed by the recording head. Problems such as damage to the print medium due to being caught and curl after discharging the print medium may occur.

In particular, the amount of ink on the print medium is large,
This problem is remarkable in the color image forming apparatus.

As a solution to the above-mentioned problems, Japanese Patent Laid-Open No. 114450/1989 uses a colorless transparent ink in addition to the three primary colors of yellow, magenta, and cyan or four primary colors including black. For example, a method of obtaining a high quality with a constant elongation rate of the recording medium by applying a colorless transparent ink on the one-color printed portion on the print medium and making the same as the total amount of ink when two-color ink is applied is known. It is disclosed.

However, as described above, the colorless transparent ink is applied onto the one-color printed portion on the print medium so that the total amount of the ink is the same as that of the two-color printing, so that the elongation rate of the print medium becomes constant. Although it is possible to make the height of the wrinkle constant, the amount of warp of the print medium cannot be reduced.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and an image forming apparatus capable of reducing the warp of a print medium after image formation,
An object of the present invention is to provide an image forming method and the obtained image formed product.

[0016]

SUMMARY OF THE INVENTION The present invention for solving the above problems is an image forming apparatus for forming an image on a print medium using a head for ejecting ink and a head for ejecting a printability improving liquid. By controlling the ejection of the printability improving liquid, the ratio of the total amount of the ink and the printability improving liquid per unit area to the total ink amount when the ink is ejected to all the pixels per unit area of the print medium. The image forming apparatus is provided with a control unit that controls the temperature within a predetermined range.

Further, according to the present invention, there is provided an image forming apparatus for forming an image on a print medium by using a head for ejecting ink and a head for ejecting the printability improving liquid, wherein the printability improving liquid is ejected. Control means for controlling the ratio of the total number of ink dots per unit area and the total number of dots of the printability improving liquid to the total number of pixels per unit area of the print medium within a predetermined range. An image forming apparatus is provided.

Further, according to the present invention, there is provided an image forming method for forming an image on a print medium by ejecting ink and the printability improving liquid, wherein by controlling the ejection of the printability improving liquid, the unit of the print medium An image forming method is characterized in that an image is formed on a print medium by controlling the ratio of the total number of ink dots per unit area and the total number of dots of the printability improving liquid to the total number of pixels per area within a predetermined range. Provided.

Further, according to the present invention, an image formed product in which an ink and a printability improving liquid are ejected to form an image on a print medium, the ink per unit area of the total number of pixels per unit area of the print medium. There is provided an image-formed product characterized in that the ratio of the total number of dots to the total number of dots of the printability improving liquid is within a predetermined range over the entire area where an image is formed.

[0020]

According to the above construction, by suppressing the warp amount of the print medium after the image formation within the allowable range, it is possible to prevent the head of the image forming apparatus and the print medium from coming into contact with each other, and to obtain a high-quality image. It is possible to reduce the curl after the medium is discharged from the image forming apparatus, and it is possible to improve the handling of the print medium after the image formation.

[0021]

EXAMPLE FIG. 6 is a diagram showing the relationship between the warp amount of the print medium and the print density. In FIG. 6A, the print density of the print range 202 on the print medium 201 is D [%]. Here, the print density is the ratio of the total amount of the ink and the printability improving liquid per unit area to the total ink amount when ink is ejected to all the pixels per unit area of the print medium. It is the ratio of the total number of ink dots per unit area and the number of dots of the printability improving liquid to the total number of pixels per unit area.

FIG. 6B shows a view of the print medium 201 of FIG. 6A as viewed from the direction of arrow M in the figure. The amount of warp of the print medium 201 after printing is k. FIG. 6C is a graph showing the relationship between the print density D [%] and the warp amount k [mm].

For example, the resolution of the image forming apparatus is 360
dpi, and 1 at every 1/360 inch with the minimum interval
Assuming that dots can be ejected, the state in which dots are printed in all directions in all pixels of the print range 202 at this minimum interval by ejecting only a single color ink liquid is 10
The print density is 0%.

In the embodiments described below, the print liquid is superposed on the ink and the printability-improving liquid is ejected. Therefore, even if the print density is 100%, dots are not necessarily formed in four directions at the above-mentioned minimum intervals. Since the dot ejection amount per unit area influences the warp of the print medium, the print density can be managed by the number of dots formed in a predetermined block (unit area). Actually, one block is set to 64 dots × 64 dots, and the print density is calculated for each block. That is, 64 in one block
The print density is 100% when X64 = 4096 dots are formed.

The present inventor has confirmed by experiments that the amount of warp of the print medium is related to the total amount of ink on the print medium, that is, the print density.

When the present inventor conducted experiments on various plain papers, the relationship shown in FIG. 6 (c) was obtained. The print density was about 100%, the amount of warpage was maximum, and the print density exceeded 60%. It was confirmed that when it was less than 140%, the front surface of the print head was rubbed with the print medium, the print head was caught at the end of the print medium, and the curl after discharging the print medium was considerably large.

When the print density is more than 60% and less than 140%, warpage occurs because the surface of the print medium on which ink is ejected and the back surface on which ink is not ejected have different elongations in the thickness direction. On the other hand, the print density is 140
When it is at least%, the amount of ink is large, the ink permeates in the thickness direction of the print medium, and there is no difference in the elongation in the thickness direction, so warpage is less likely to occur.

Here, 64 × 64 = 409 in one block.
If 6 dots are formed and the print density is 100%, the print density of 60% means 4096 × 0.6.
= 2457.6 dots are formed in one block. The print density of 140% means 4096 ×
This is a state in which 1.4 = 5734.4 dots are formed in one block. Therefore, if the total number of pixels in one block is set to 64 dots x 64 dots, the print density is 60%.
Controlling the print density to 140% or more or below is to control the ejection of the printability improving liquid as necessary so that the total number of dots T in each block is T ≦ 2457 or T ≧ 5735. The ejection amount of the printability improving liquid is set to 70 pl / dot, similar to the ink.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic perspective view of an image forming apparatus to which the present invention can be applied.

In FIG. 1, the print medium 10 includes a transport roller 2, a pressure contact roller 3, a paper discharge roller 4, and a spur shaft 11.
It is supported by a spur 12 which is rotatably supported, and the transport roller 2 and the discharge roller 4 are rotationally driven by a drive motor (not shown), and are transported in the direction of arrow A in the figure.

The pressing roller 3 and the spur shaft 11 are urged toward the conveying roller 2 and the discharging roller 4 by pressing springs (not shown) for holding the print medium 10 therebetween. . A pair of guide shafts 5 are provided on the front side of the transport roller 2 and the paper discharge roller 4 in parallel with them, and the carriage 6 is driven by the drive motor 7 along the guide shafts 5. It is reciprocally driven in the direction of arrow B in the figure via the belt 8.

An ink jet print head 90 is mounted on the carriage 6. The inkjet print head 90 is a head for forming a color image, and has a printability improving liquid ejecting head 9A, a cyan ink ejecting head 9B, a magenta ink ejecting head 9C, and a yellow ink in the main scanning direction (arrow B direction). -Ink ejection head 9D and black ink ejection head 9E are arranged. Ejecting ports for the printability improving liquid or ink are formed at a predetermined pitch at a position facing each print medium 10 of each head, and a heating resistor provided in a nozzle communicating with each ejecting port based on image information. An image is formed by driving an electrothermal converter such as the above to cause a state change in the ink or the like, ejecting a droplet from the ejection port, and applying the ink or the like to the print medium 10.

FIG. 2 is a block diagram showing the control arrangement of the image forming apparatus according to an embodiment of the present invention. CPU1
00 constitutes the control means according to the present invention,
According to the processing procedure stored in the M100A, control of each part of the apparatus and data processing are executed. Transport motor 60M
Is a motor for driving the transport roller 2, the pressure contact roller 3, and the paper discharge roller 4 shown in FIG.
It is controlled via the motor driver 60D. Similarly, the carriage motor 20M is a motor for moving the carriage 6, and is controlled via the carriage motor driver 20D. The ink ejection from the head 90 is controlled via the head driver 90D based on the image data sent from the host device.

FIG. 3 shows that the CPU 100 executes 1
6 is a flowchart showing a control method for correcting the discharge amount of the printability improving liquid in the block. First, step S1
Then, the number of dots of the initial printability improving liquid is set to one half of the number of ink dots. Next, based on the image data, the total number of dots of the ink and the printability improving liquid is calculated in step S2. In step S3, step S2
The total number of dots obtained in step S is T ≦ 2457 or T ≧ 573
If YES, the process proceeds to step S4 and printing is performed with this total number of dots. On the other hand, step S3
In case of 2458 ≦ T ≦ 5734, step S5
In, the correction of the discharge amount of the printability improving liquid is added. That is, the total number of dots T is T ≦ 2457 or T ≧ 573.
The number of dots of the printability improving liquid is increased one by one until it falls within the range of 5, and then when this condition is satisfied, step S4
Record at.

The printability improving liquid ejecting head 9A has the CPU 1 prior to the ink ejecting heads 9B, 9C, 9D and 9E ejecting ink onto the print medium 10.
The printability improving liquid is discharged to the discharge position calculated by 00.

The total amount of ink ejected onto the print medium 10 and the total amount of printability improving liquid are calculated by the CPU 100, and the total amount of ink and printability improving liquid applied to the print medium shown in FIG. 6C is calculated. Based on the ratio (print density) D to the total amount of ink for all pixels and the warp amount k of the print medium, the CPU 100 again calculates the ejection amount of the printability improving liquid, determines the ejection position, and based on the result. , The heads 9A, 9 with respect to the print medium
The printability improving liquid and the ink are ejected from B, 9C, 9D and 9E to form an image on the print medium.

In this embodiment, when an image is formed on plain paper, the warp amount k of the print medium is large when the print density is more than 60% and less than 140% as described above, and the head is placed on the print medium. Since there is a risk of contact, the print density is set to 60% or less or 140% or more.

FIG. 4 shows a specific method of ejecting the ink and the printability improving liquid of this embodiment. 4 (a) to 4
In (d), the ratio of the ink amount to the total ink amount of all pixels for the print medium is 25%, 50%,
The relationship between the ratio of the applied amount of the printability improving liquid in the case of 100% and 200% and the position where the dots of the printability improving liquid are arranged is shown. It should be noted that the diagram showing the arrangement of the dots shows only the positions of the dots, not the size of the dots.

The printability-improving liquid reacts with the ink to generate its effect, so that it is always applied to the positions where the dots of the ink are arranged. When the ink dots are printed in one color, the ratio of the amount of the ink to the printability improving liquid is 1: 1. When the ink dots are two-color prints (printing by mixing colors), the ink and the printability improving liquid are used. Although the amount of day is 2: 1, it has been experimentally confirmed that the function can be sufficiently achieved even if the printability improving liquid is discharged with such a ratio value.

FIG. 4B shows the case where the ink amount ratio is 50%. In this case, the ratio of the total amount is 100% when the printability improving liquid is simply ejected to the dot positions of the ink. Therefore, the ratio of the total amount is set to 150%,
The printability-improving liquid is also ejected onto the area where the ink dots are not located.

In this example, an ink having the following composition and a printability improving liquid were used. (Ink) 1. Yellow diethylene glycol 10 parts by weight Isopropyl alcohol 2 parts by weight Urea 5 parts by weight Acetylenol EH 1 part by weight C.I. I. Direct Yellow 86 3 parts by weight Water balance 2. Magenta diethylene glycol 10 parts by weight Isopropyl alcohol 2 parts by weight Urea 5 parts by weight Acetylenol EH 1 part by weight C.I. I. Acid Red 289 3 parts by weight Water balance 3. Cyanidiethylene glycol 10 parts by weight Isopropyl alcohol 2 parts by weight Urea 5 parts by weight Acetylenol EH 1 part by weight C.I. I. Direct Blue 199 3 parts by weight Water balance 4. Black thiodiglycol 5 parts by weight Glycerin 5 parts by weight Isopropyl alcohol 4 parts by weight Urea 5 parts by weight C.I. I. Food Black 3 parts by weight Water remaining (printability improving liquid) Polyallylamine-hydrochloride 1 part by weight Benzalkonium chloride 1 part by weight Thiodiglycol 10 parts by weight Acetylenol EH 0.5 parts by weight Water remaining part

With the above composition, ink that has a relatively high penetration speed into the print medium is used as the color ink to reduce ink bleeding between the color print areas, and as black ink, penetrate into the print medium. By using an ink having a relatively low speed, it is possible to obtain a high-density black image in which feathering hardly occurs.

In the above-described mixing of the printability improving liquid and the ink, the above-mentioned printability improving liquid and the ink are mixed at the position on the print medium or at the position where the ink has penetrated, and as a result, the printability is improved as the first step of the reaction. Among the cationic substances contained in the liquid, a low molecular weight component or a cationic oligomer and a water-soluble dye having an anionic group used in the ink or an anionic compound used in the ink are used. An ionic interaction causes association, and instantaneously causes separation from the solution phase. As a result, dispersion destruction occurs in the pigment ink, and pigment aggregates are formed.

Next, as the second step of the reaction, the above-mentioned dye and a low molecular weight cationic substance or cationic oligomer are used.
The aggregate of the pigment or the aggregate of the pigment is adsorbed by the polymer component contained in the printability improving liquid, so that the size of the aggregate of the dye or the aggregate of the pigment generated by the association is further increased, and the print medium. It becomes difficult to enter into the gap between the fibers, and as a result, only the liquid portion that has undergone solid-liquid separation penetrates into the print medium, so that both print quality and fixability are achieved. At the same time, the agglomerates or pigment agglomerates formed by the low molecular weight component of the cationic substance or the cationic oligomer, the anionic dye and the cationic substance produced by the mechanism as described above have a high viscosity, and the movement of the solvent body Since they do not move together with each other, even if adjacent ink dots are formed of different color inks as in full-color image formation, they do not mix with each other and bleeding does not occur. In addition, the above-mentioned aggregate is essentially insoluble in water, and the water resistance of the formed image is perfect. Further, it also has the effect of improving the light fastness of an image formed by the shielding effect of the polymer.

In the present specification, the effect of improving the printability of the printability-improving liquid can be achieved only by the first step, and preferably both of the first step and the second step. Achieved by The printability is improved by improving image quality such as density, saturation, sharpness of edge portion, dot diameter and the like, ink fixability, weather resistance such as water resistance and light resistance, that is, image storability. At least one of the things is obtained.

Further, in carrying out the present invention, it is not necessary to use a cationic polymer substance having a large molecular weight or a polyvalent metal salt as in the prior art, or even if it is necessary, the effect of the present invention. Since it is only necessary to use it as an auxiliary in order to further improve, the usage amount can be minimized. As a result, the deterioration of the color developability of the dye, which is a problem when trying to obtain the water resistance effect by using the conventional cationic polymer substance or polyvalent metal salt, is eliminated.

The print medium used for carrying out the present invention is not particularly limited.
Conventionally used so-called plain paper such as copy paper and bond paper can be preferably used. Of course, specially made coat paper and OH for inkjet printing
A transparent film for P can also be suitably used, and general high-quality paper or glossy paper can also be suitably used.

Further, the ink jet printing apparatus of the present invention is not only a printer, a copying machine, a facsimile machine or other office equipment, but also a large size system such as a decorative printer or a computer design printing system for directly printing a pattern on a cloth. It can also be used as a mass production device such as a printing device.

As the color material of each ink, for example, a pigment-containing material or a mixture of a dye and a pigment may be used.

The following can be mentioned as an example of the pigment ink which causes aggregation by mixing with the above-mentioned printability improving liquid. That is, as described below,
Yellow, magenta, cyan, and black color inks, each containing a pigment and an anionic compound, Y2, M2, C2
And K2 can be obtained.

Black ink K2 anionic polymer P-1 (styrene-methacrylic acid-ethyl acrylate, acid value 400, weight average molecular weight 6,0)
00, an aqueous solution with a solid content of 20%, a neutralizing agent: potassium hydroxide) was used as a dispersant, and the following materials were placed in a batch type vertical sand mill (made by AIMEX Co., Ltd.) and 1 mm diameter glass beads were filled as a medium. Then, while cooling with water, 3
Time-dispersed processing was performed. Viscosity after dispersion is 9 cps, pH
Was 10.0. This dispersion was centrifuged to remove coarse particles, to prepare a carbon black dispersion having a weight average particle diameter of 100 nm. (Composition of carbon black dispersion) -P-1 aqueous solution (solid content 20%) 40 parts-Carbon black Mogul L (manufactured by Cablack Co.) 24 parts-Glycerin 15 parts-Ethylene glycol monobutyl ether 0 .5 parts-Isopropyl alcohol 3 parts-Water 135 parts

Next, the dispersion obtained above was sufficiently diffused to obtain a black ink K2 for ink jet containing a pigment. The solid content of the final preparation was about 10%.

Yellow-ink Y2 anionic polymer P-2 (styrene-acrylic acid-methyl methacrylate, acid value 280, weight average molecular weight 1
1,000, an aqueous solution with a solid content of 20%, a neutralizing agent: diethanolamine) was used as a dispersant, and the following materials were used to carry out a dispersion treatment in the same manner as in the preparation of the black ink K2. A yellow color dispersion having a particle size of 103 nm was prepared. (Composition of yellow-color dispersion) P-2 aqueous solution (solid content 20%) 35 parts C.I. I. Pigment Yellow 180 24 parts (Novapa Muier PH-G, manufactured by Hoechst) -Triethylene glycol 10 parts-Diethylene glycol 10 parts-Ethylene glycol monobutyl ether 1.0 part-Isopropyl alcohol 0 .5 parts ・ Water 135 parts

Next, the yellow color dispersion obtained above was sufficiently diffused to obtain an inkjet yellow ink Y2 containing a pigment. The final product has a solid content of about 1
It was 0%.

Cyan ink C2 Black ink K2 was prepared by using the anionic polymer P-1 used as a dispersant and using the materials shown below, as in the case of the carbon black dispersion described above. Dispersion treatment was performed to prepare a cyan color dispersion having a weight average particle diameter of 120 nm. (Composition of cyan color dispersion) P-1 aqueous solution (solid content 20%) 30 parts C.I. I. Pigment Bull-15: 3 24 parts (Fast Gemble-FGF, manufactured by Dainippon Ink & Chemicals, Inc.)-Glycerin 15 parts-Diethylene glycol monobutyl ether 0.5 parts-Isopropyl alcohol 3 parts-Water 135 parts

Next, the cyan color dispersion obtained above was sufficiently diffused to obtain a cyan ink C2 for ink jet containing a pigment. The final product has a solids content of about 9.6.
%Met.

The anionic polymer P-1 used in the preparation of the magenta ink M2 black ink K2 was used as a dispersant, and the following materials were used, the same as in the case of the carbon black dispersion described above. Dispersion treatment was performed to prepare a magenta color dispersion having a weight average particle diameter of 115 nm. (Composition of magenta color dispersion) P-1 aqueous solution (solid content 20%) 20 parts C.I. I. Pigment Red 122 (manufactured by Dainippon Ink & Chemicals, Inc.) 24 parts ・ Glycerin 15 parts ・ Isopropyl alcohol 3 parts ・ Water 135 parts

Next, the magenta color dispersion obtained above was sufficiently diffused to obtain a magenta ink M2 for ink jet containing a pigment. The solid content of the final preparation was about 9.2%.

(Embodiment 2) Hereinafter, a method for ejecting ink and printability improving liquid when an image forming apparatus in which the ejection amount of the printability improving liquid ejecting head is variable will be described. The image forming apparatus used in this embodiment is the same as the image forming apparatus described in the first embodiment except that the ejection amount of the printability improving liquid ejecting head is variable, and a detailed description thereof will be omitted.

FIG. 5 is a diagram for explaining a specific method for ejecting ink and printability improving liquid according to the second embodiment.
Similar to FIG. 4, in FIGS. 5A to 5D, the ink amount ratio to the print medium is 25%, 50%, and 10%, respectively.
The ratio of the discharge amount of the printability improving liquid and the arrangement of dots of the printability improving liquid in the case of 0% and 200% are shown.

5 (b) and 5 (d) show the first embodiment.
However, as described above, the printability improving liquid exerts a sufficient function when the amount of ink which is ½ of the ink amount is applied. Therefore, in FIG. 3A and FIG. The ejection amount of the printability improving liquid ejection head is set to the ink ejection amount (70 p
It is changed to 1/2 of 1), that is, 35 pl to reduce the consumption of the printability improving liquid.

An image formed product in which an image is formed on a print medium by ejecting the ink and the printability improving liquid according to the above-mentioned embodiment, and the image is formed per unit area of the print medium with respect to the total number of pixels. It was possible to obtain an image-formed product characterized in that the ratio of the total number of ink dots to the total number of dots of the printability improving liquid was within a predetermined range over the entire area where an image was formed. The printed matter obtained in this way has an amount of warpage after image formation suppressed within an allowable range, maintains a high-quality image, reduces rounding after being discharged from the image forming apparatus, and is easy to handle. It was

Further, the printability improving liquid acts on the ink to improve the fixability of the ink, and the bleeding at the boundary between the black portion and the color portion is reduced to obtain a high-quality image. I was able to.

Further, since the amount of warp of the print medium after image formation can be suppressed within an allowable range, contact between the head of the image forming apparatus and the print medium is prevented, and image contamination and damage to the head and print medium are prevented. I was able to prevent it.

(Others) In the present invention, the means for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system (for example, electrothermal converter or laser light). ), And brings about an excellent effect in a recording head and a recording apparatus of a system in which a change in ink state is caused by the thermal energy. This is because such a system can achieve high density recording and high definition recording.

With regard to its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
At least one drive signal corresponding to recorded information and giving a rapid temperature rise exceeding nucleate boiling is applied to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored. As a result, the heat energy is transferred to the electrothermal converter.
Is effective to cause film boiling on the heat acting surface of the recording head, and as a result, bubbles can be formed in the liquid (ink) corresponding to this drive signal in a one-to-one correspondence. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications, A configuration using US Pat. No. 4,558,333 or US Pat. No. 4,459,600, which discloses a configuration in which the heat acting portion is arranged in the bending region, may be used.

In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a structure in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters.
It is also possible to adopt a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which the opening for absorbing the pressure wave of (1) corresponds to the discharge portion. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. As such a recording head, a combination of a plurality of recording heads satisfies the length,
Any of the configurations as one recording head may be used.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the ink is supplied from the apparatus main body when electrically connected to the apparatus main body by being attached to the apparatus main body. It is also possible to use a replaceable chip type recording head capable of performing the above or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. to the recording head because the effects of the present invention can be further stabilized. Specific examples thereof include capping means, cleaning means, pressurizing or suctioning means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and recording. It is also effective to perform stable recording by performing a preliminary discharge mode for performing discharge different from the above.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but the ink solidifies at room temperature or lower and softens at room temperature, or is a liquid. Or, in the above-mentioned inkjet method, it is general that the temperature of the ink itself is adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. It is sufficient that the ink is in a liquid state when applied.

In addition, the temperature rise due to the thermal energy is positively prevented by being used as the energy for changing the state of the ink from the solid state to the liquid state, or the ink is left standing for the purpose of preventing the evaporation of the ink. Either using solidifying ink, the ink is liquefied by application of thermal energy according to the recording signal, and ejected as liquid ink, or the one that already begins to solidify when it reaches the recording medium, etc. The use of an ink having the property of being liquefied only by thermal energy as described above is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or JP-A No. 60-71260, so as to face the electrothermal converter in the state of being held as a liquid or a solid in the recesses or through holes of the porous sheet. It may be in any form. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, as a form of the recording apparatus according to the present invention, other than the one provided integrally or separately as the image output terminal of the information processing equipment such as the word processor or the computer as described above, It may be in the form of a copying machine combined with a reader or the like, or a facsimile machine having a transmission / reception function.

FIG. 8 is a block diagram showing a schematic configuration when the recording apparatus of the present invention is applied to an information processing apparatus having the functions of a word processor, a personal computer, a facsimile machine and a copying machine. .

In the figure, reference numeral 1801 denotes a control unit for controlling the entire apparatus, which includes a CPU such as a microprocessor and various I / Os.
It is equipped with a port and outputs control signals and data signals to each section and inputs control signals and data signals from each section for control. A display unit 1802 displays various menus, document information, image data read by the image reader 1807, and the like.
A transparent pressure-sensitive touch panel 1803 is provided on the display unit 1802. By pressing the surface of the touch panel 1803 with a finger or the like, items or coordinate positions can be input on the display unit 1802.

1804 is an FM (Frequency M)
sound source section, the music information created by a music editor or the like is stored in the memory section 1810 or the external storage device 18
The data is stored as digital data in 12, and is read from the memory or the like to perform FM modulation. FM
The electric signal from the sound source unit 2804 is converted into an audible sound by the speaker unit 1805. The printer unit 1806 has the recording apparatus according to the present invention applied as an output terminal of a word processor, a personal computer, a facsimile apparatus, and a copying apparatus.

Reference numeral 1807 denotes an image reader portion for photoelectrically reading and inputting original data, which is provided in the middle of the original feeding path and reads various originals in addition to facsimile originals and copy originals. Reference numeral 1808 denotes a facsimile transmission of original data read by the image reader unit 1807,
It is a facsimile transmission / reception unit that receives and decodes a transmitted facsimile signal and has an interface function with the outside. Reference numeral 1809 denotes a telephone unit having various telephone functions such as a normal telephone function and an answering machine function.

Reference numeral 1810 denotes a ROM for storing system programs, manager programs, other application programs, character fonts, dictionaries, etc.
It is a memory unit including a RAM for storing the application program and character information loaded from the external storage device 1812, a video RAM, and the like.

Reference numeral 1811 denotes a keyboard section for inputting document information and various commands. An external storage device 1812 uses a floppy disk, a hard disk, or the like as a storage medium. The external storage device 1812 stores character information, music or voice information, a user application program, and the like.

FIG. 9 is an external view of the information processing apparatus shown in FIG. In the figure, reference numeral 1901 denotes a flat panel display using liquid crystal or the like, which displays various menus, graphic information, document information and the like. A touch panel 1803 is installed on the display 1901. By pressing the surface of the touch panel 1803 with a finger or the like, coordinate input or item designation input can be performed. 1902 is a handset used when the device functions as a telephone.

The keyboard 1903 is detachably connected to the main body via a code, and various character information and various data are stored.
Data can be input. Also, this keyboard 19
03 is provided with various function keys 1904 and the like. 1
Reference numeral 905 is an insertion port of a floppy disk into the external storage device 1812.

Reference numeral 1906 denotes a paper placing portion on which an original read by the image reader portion 1807 is placed, and the read original is discharged from the rear portion of the apparatus. When receiving a facsimile or the like, the image is recorded by the inkjet printer 1907.

The display 1802 is a CRT.
However, a flat panel such as a liquid crystal display using a ferroelectric liquid crystal is preferable. This is because in addition to being small and thin, it is possible to reduce the weight. When the information processing apparatus functions as a word processor, the character information input from the keyboard section 1811 in FIG. 8 is processed by the control section 1801 according to the document processing program and output as an image to the printer section 1806. It

The above information processing apparatus is a personal computer.
In the case of functioning as data, various data input from the keyboard section 1811 are calculated by the control section 1801 in accordance with the application program, and the printer section 1811.
The calculation result is output as an image in 06.

When functioning as a receiver of a facsimile apparatus, a facsimile transmission / reception unit 1808 is provided via a communication line.
The facsimile information input from the printer unit 1 is received by the control unit 1801 according to a predetermined program, and the printer unit 1
The received image is output to 806.

Further, when functioning as a copying apparatus, a document is read by the image reader unit 1807, and the read document data is transferred to the printer unit 1 via the control unit 1801.
It is output to 806 as a copied image. When functioning as a transmitter of a facsimile machine, document data read by the image reader unit 1807 is stored in the control unit 1.
After transmission processing according to a predetermined program by 801 is performed, it is transmitted to the communication line via the facsimile transmission / reception unit 1808.

The information processing apparatus described above may be an integral type in which an ink jet printer is built in the main body as shown in FIG. 10, and in this case, the portability can be further enhanced. In the figure, parts having the same functions as those in FIG. 9 are designated by the corresponding reference numerals.

By applying the recording apparatus of the present invention to the multifunctional information processing apparatus described above, a high-quality recorded image can be obtained, so that the function of the information processing apparatus can be further improved. Become.

[0092]

As described above, according to the present invention,
By suppressing the amount of warp of the print medium after image formation within the allowable range, it is possible to prevent contact between the head of the image forming apparatus and the print medium to obtain a high-quality image, and after the print medium is discharged from the image forming apparatus. It is possible to reduce the rounding and improve the handling of the print medium after image formation.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an inkjet printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of electrical control of the inkjet printing apparatus according to the present invention.

FIG. 3 is a flowchart showing a procedure for correcting the ejection amount of the printability improving liquid.

FIG. 4 is a diagram for explaining a total amount of ink and printability improving liquid and a dot arrangement of ink and printability improving liquid in Example 1.

FIG. 5 is a diagram for explaining a total amount of ink and printability improving liquid and a dot arrangement of ink and printability improving liquid in Example 2.

FIG. 6 is an explanatory diagram showing a relationship between a warp amount of a print medium and print density.

FIG. 7 is an illustration showing wrinkles and warpage of the print medium.

FIG. 8 is a block diagram showing an example of an information processing system using the inkjet printing apparatus according to each of the above embodiments.

FIG. 9 is an external perspective view of the system.

FIG. 10 is an external view showing another example of the system.

[Explanation of symbols]

 2 Conveyor Roller 4 Paper Ejecting Roller 5 Guide Shaft 6 Carriage 9A Printability Improving Liquid Head 9B, 9C, 9D, 9E Ink Head 10 Print Medium 90 Inkjet Printhead Unit 90D Head Driver 100 CPU 100A ROM 100B RAM

Claims (8)

[Claims] 1. An image forming apparatus for forming an image on a print medium using a head for ejecting ink and a head for ejecting printability improving liquid, wherein the ejection of the printability improving liquid is controlled. And a control means for controlling the ratio of the total amount of ink and printability improving liquid per unit area to the total amount of ink when ink is ejected to all pixels per unit area of the print medium within a predetermined range. A characteristic image forming apparatus. 2. An image forming apparatus for forming an image on a print medium using a head for ejecting ink and a head for ejecting printability improving liquid, wherein the ejection of the printability improving liquid is controlled. The image forming method further comprises a control means for controlling the ratio of the total number of ink dots per unit area and the total number of dots of the printability improving liquid to the total number of pixels per unit area of the print medium within a predetermined range. apparatus. 3. The image forming apparatus according to claim 2, wherein the ratio is 60% or less or 140% or more. 4. The image according to claim 1, wherein the printability improving liquid contains a cationic substance having a low molecular weight component and a high molecular weight component, and the ink contains an anionic dye. Forming equipment. 5. The printability improving liquid contains a cationic substance having a low molecular component and a high molecular component, and the ink contains an anionic compound and a pigment.
4. The image forming apparatus according to any one of 3 to 3. 6. The head is a head for ejecting ink or a printability improving liquid by using heat energy, and generating heat energy for generating heat energy given to the ink or the printability improving liquid. The image forming apparatus according to claim 1, further comprising a body. 7. An image forming method for forming an image on a print medium by ejecting ink and a printability improving liquid, wherein the ejection of the printability improving liquid is controlled so that the total area per unit area of the print medium is increased. An image forming method comprising: forming an image on a print medium by controlling the ratio of the total number of ink dots per unit area to the number of pixels and the total number of dots of the printability improving liquid within a predetermined range. 8. An image formed product in which an image is formed on a print medium by ejecting ink and a printability improving liquid, wherein the number of ink dots per unit area and the number of prints per unit area of the print medium. An image-formed product, wherein the ratio of the total number of dots of the property-improving liquid is within a predetermined range over the entire area where the image is formed.