JPH0741726A - Coating material for recording medium, and ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To enable a stable high-quality ink jet recording without being affected by the condition of preservation of the recording medium used by applying a coating material contg. a polyvinyl alcohol having a specified degree of saponification to the medium after it is printed by ink jet recording. CONSTITUTION:The coating material is used for coating a recording medium after the medium is printed by ink jet recording, and contains a partially saponified polyvinyl alcohol with a degree of saponification of 60-97.5% or a fully saponified polyvinyl alcohol with a degree of saponification of 97.5% or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating material for coating the surface of a recording medium on which ink-jet recording has been carried out, and in particular, it provides stable, high-quality image quality without being affected by the storage state of the recording medium. The present invention relates to a coating material for a recording medium that can be maintained. Furthermore, the present invention relates to an inkjet recording apparatus for coating an image on a recording medium and then coating the coating material.

[0002]

2. Description of the Related Art Ink jet recording systems use various ink ejection systems such as an electrostatic suction system, a system in which a piezoelectric element is used to mechanically vibrate or displace the ink, and the ink is heated and foamed to utilize its pressure. The method is to generate and fly small droplets of ink, and then attach some or all of them to a recording medium such as paper for recording, which produces less noise, high-speed printing, and high-quality printing. It is attracting attention as a recording method that enables printing and multicolor printing.

The inks used for such ink jet recording include solid inks that are melted by heat and liquid inks in which a dye is dissolved in water or a solvent.
Liquid ink is often used in inexpensive devices.

[0004]

However, in the case of printing with liquid ink, the ink adhering to the recording medium is dissolved again by writing with a water-based pen or by sweat or moisture of humidity, resulting in color loss or tailing. Occurs. Further, there is a problem that the print quality is deteriorated due to various factors such as fading due to light irradiation and scratches due to external impact.

Therefore, the present invention provides a coating material for a recording medium which solves the above-mentioned problems and enables stable high-quality ink jet recording without being affected by the storage state of the recording medium. Where it is.

[0006]

The above-mentioned problems can be solved by the present invention described below. That is, the present invention provides a partially saponified polyvinyl alcohol having a saponification rate of 60 to 97.5% in a coating material used for coating after the ink is deposited by inkjet recording on a recording medium used for inkjet recording. Or a fully saponified polyvinyl alcohol having a saponification rate of 97.5% or more.

Further, the ink jet recording apparatus of the present invention ejects recording ink according to a recording signal to record an image on a recording medium, a delaying means for delaying the recording signal, and the delaying means. And a coating means for coating the recording material on the recording medium after recording according to the output signal of the recording medium.

[0008]

FUNCTION The structural formula of polyvinyl alcohol is shown in [Chemical formula 1].

[0009]

[Chemical 1]

This is produced by hydrolyzing polyvinyl acetate having the structural formula shown in [Chemical Formula 2] in an alkali.

[0011]

[Chemical 2]

As described above, polyvinyl alcohol is generally referred to as polyvinyl acetate having some or all of the COOR groups replaced with OH groups. Particularly, polyvinyl alcohol having 97.5% or more of this substitution is used. Fully saponified polyvinyl alcohol, less than 97.5% is sometimes called partially saponified polyvinyl alcohol, and the rate of this substitution changes the solubility in a solvent.

Regarding the solubility in water, the completely saponified polyvinyl alcohol has a characteristic that it swells in room temperature water at about 20 ° C. but hardly dissolves, and dissolves in warm water at 80 ° C. or higher. The lower the rate of substitution with OH groups, the higher the solubility in room temperature water.

Further, it shows almost no solubility in solvents other than water, but it shows solubility in methanol and ethanol in a mixed solvent with water, and in fully saponified polyvinyl alcohol, methanol and ethanol are 40%. It can be dissolved in a mixed solvent to a certain extent,
It has a characteristic that it becomes more soluble in a mixed solvent having a higher mixing ratio of methanol and ethanol as the replacement ratio with the H group becomes lower.

In the present invention, the saponification rate is 60 to 9
7.5% partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol having a saponification rate of 97.5% or more is selected, and the recording material is coated with a recording ink to which the recording ink is adhered. Form a coating film on the recording medium. This enables stable high-quality ink jet recording without being affected by the storage of the recording medium.

Further, the saponification rate is 60 to 97.5%.
Partially saponified polyvinyl alcohol or saponification rate 9
When forming a coating film on a recording medium with a coating material containing 7.5% or more of completely saponified polyvinyl alcohol, the characteristics of the coating film change depending on the degree of polymerization of the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol. To do. In the present invention, the average degree of polymerization of the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol contained is 15
0 to 750, coating material having a content of partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol of 0.2 to 30%, average of partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol contained When the degree of polymerization is 750 to 2000, the coating material has a partially saponified polyvinyl alcohol content or a fully saponified polyvinyl alcohol content of 0.1 to 20%, a partially saponified polyvinyl alcohol content, or a fully saponified polyvinyl alcohol content. When the average degree of polymerization of alcohol is 2000 to 5000, by forming a coating film with a coating material having a content of partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol of 0.05 to 15%, moisture and light can be reduced. Or Enabling high-quality ink jet recording which is stable attack less susceptible to.

As can be seen from the fact that polyvinyl alcohol is widely used as a synthetic paste and an additive when making paper from pulp, it is a very inexpensive material, and it is possible to provide an inexpensive coating material. It is possible. As described above, the coating material for a recording medium according to the present invention is a coating on an inexpensive recording medium that enables stable high-quality ink jet recording without being affected by the storage state of the recording medium. It is a material.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. However, these embodiments specifically describe the present invention, and the embodiment is not limited thereto. (Example 1) 3 g of completely saponified polyvinyl alcohol having an average degree of polymerization of 550 and a saponification rate of 98.5% was placed in a mixed solvent of 95 g of ion-exchanged water and 2 g of ethanol and allowed to swell sufficiently, followed by a hot water bath. It heated and melt | dissolved and the coating material was produced.

This coating material was applied to an ink jet recording apparatus filled with an ink having the following composition to
The recording medium on which dots of 00 dots were printed was coated with a bar coater and dried. Here, as the recording medium, plain paper PPC-K (trade name of Daishowa Paper Manufacturing Co., Ltd.), which is a general recording paper for electrophotography generally called PPC, was used.

(Ink Composition) C. I. DirectBlack 168 3.0% by weight Ethanol 8.0% by weight Diethylene glycol 8.0% by weight Ion-exchanged water 81.0% by weight Also, prepare a recording medium on which 100 dots are printed by the same device and not coated. A comparison was made. The size of the opening of the nozzle orifice of the ink jet recording apparatus used in this example is 25 μm in length and 40 in width.
It has a square shape of μm, and ink droplets having a diameter of about 30 to 40 μm can be ejected at one time.

Pure water was dropped on the printed dots on the recording medium, the water was wiped off after 30 seconds, and the optical density of the dots (hereinafter referred to as OD value) was measured. As a result, coating was performed using a coating material. When printing was performed on the recording medium, all the dots were O. When the D value was reduced by about 0.2, the D value was maintained at 1.4 or more, and the roundness was not significantly affected. In other words, the coating maintained high-quality printing. However, plain paper P without coating
When printing on PC-K, When the D value is reduced by about 0.5, the optical density is greatly reduced to 1.0 or more, and further,
Due to the bleeding of the fibers of the paper, the shape of the dots was greatly broken from the perfect circle, and high-quality printed records could not be expected.

As described above, it was confirmed that the coating material for the recording medium of the present invention improves the water resistance, suppresses the influence of the storage state of the recording medium, and can maintain stable and high quality image. The coating material used in Example 1 contained 3% by weight of completely saponified polyvinyl alcohol having an average degree of polymerization of 550, but a smaller content, specifically about 0.2% by weight. In the above, the effect of the present invention could be recognized. Further, when the average degree of polymerization is in the range of 150 to 750, partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol shows almost similar solubility and can be used as a coating material up to a content of about 30% by weight. It showed good solubility. The effect of the present invention was confirmed even when the content of the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol in the coating material was larger than the value in Example 1.

Example 2 1.2 g of partially saponified polyvinyl alcohol having an average degree of polymerization of 1700 and a saponification rate of 82%
Was placed in a mixed solvent of 73.8 g of ion-exchanged water and 25 g of ethanol, allowed to swell sufficiently, then heated by a water bath and dissolved to prepare a coating material.

This coating material was applied to an ink jet recording apparatus filled with an ink having the following composition to
The recording medium on which dots of 00 dots were printed was coated with a bar coater and dried. Here, as the recording medium, plain paper PPC-K (trade name of Daishowa Paper Manufacturing Co., Ltd.), which is a general recording paper for electrophotography generally called PPC, was used.

(Ink Composition) C. I. DirectBlue 199 4.0% by weight Ethanol 10.0% by weight Triethylene glycol 15.0% by weight Isopropyl alcohol 5.0% by weight Ion-exchanged water 66.0% by weight Also, 100 dots are printed and coated by the same device. A recording medium not subjected to the above was prepared and compared. The size of the opening of the nozzle orifice of the ink jet recording apparatus used in this example is 25 μm in length and 40 in width.
It has a square shape of μm, and ink droplets having a diameter of about 30 to 40 μm can be ejected at one time.

Pure water was dropped on the printed dots on the recording medium, the water was wiped off after 30 seconds, and the optical density of the dots was measured. As a result, in the printing on the recording medium coated with the coating material, Any dot is O. When the D value was reduced by about 0.3, the D value was maintained at 1.3 or more, and the roundness was not significantly affected. In other words, the coating maintained high-quality printing. However, when printing on plain paper PPC-K which is not coated, O. When the D value is reduced by about 0.5, the optical density is greatly reduced to 1.0 or more, and the bleeding of paper fibers causes the shape of dots to be greatly broken from a perfect circle. It was something I couldn't hope for.

As described above, it was confirmed that the coating material of the recording medium of the present invention improves the water resistance, suppresses the influence of the storage state of the recording medium, and can maintain stable and high quality image. The coating material used in Example 2 contained 1.2% by weight of partially saponified polyvinyl alcohol having an average degree of polymerization of 1700.
The effect of the present invention could be recognized at a lower content, specifically, a content of about 0.1% by weight. Further, in the range of the average degree of polymerization of 750 to 2000,
Partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol showed similar solubilities, with solubilities usable as coating materials up to a content of almost 20% by weight. The effect of the present invention was confirmed even when the content of the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol in the coating material was larger than the value in Example 2.

(Example 3) 0.5 g of partially saponified polyvinyl alcohol having an average degree of polymerization of 2300 and a saponification rate of 95%
Was placed in a mixed solvent of 95 g of ion-exchanged water and 4.5 g of ethanol to be sufficiently swollen, and then heated by a hot water bath and dissolved to prepare a coating material.

An ink jet recording apparatus filled with an ink having the following composition was used to apply the coating material 1
The recording medium on which dots of 00 dots were printed was coated with a bar coater and dried. (Ink composition) C.I. I. DirectBlack 168 3.0% by weight Ethanol 10.0% by weight Diethylene glycol 5.0% by weight Ion-exchanged water 82.0% by weight In addition, a 100-dot dot is printed by a similar device and a recording medium without coating is prepared. A comparison was made. The size of the opening of the nozzle orifice of the ink jet recording apparatus used in this example is 25 μm in length and 40 in width.
It has a square shape of μm, and ink droplets having a diameter of about 30 to 40 μm can be ejected at one time.

Pure water was dropped on the printed dots on the recording medium, the water was wiped off after 30 seconds, and the optical density of the dots was measured. As a result, in the printing on the recording medium coated with the coating material, Any dot is O. When the D value was reduced by about 0.2, the D value was maintained at 1.4 or more, and the roundness was not significantly affected. The coating maintained high-quality printing. However, when printing on plain paper PPC-K without coating,
O. When the D value is reduced by about 0.5, the optical density is greatly reduced to 1.0 or more, and the bleeding of paper fibers causes the shape of dots to be greatly broken from a perfect circle. It was something I couldn't hope for.

As described above, it was confirmed that the coating material of the recording medium of the present invention has improved water resistance and can maintain stable and high-quality image quality while suppressing the storage state of the recording medium. The coating material used in Example 3 contained 0.5% by weight of partially saponified polyvinyl alcohol having an average degree of polymerization of 2300, but a smaller content, specifically about 0.05% by weight. The effect of the present invention could be recognized in the content. Also,
When the average degree of polymerization is in the range of 2000 to 5000, the partially saponified polyvinyl alcohol or the fully saponified polyvinyl alcohol shows almost the same solubility, and up to the content of about 15% by weight, the solubility that can be used as a coating material is high. Showed sex. The effect of the present invention was confirmed even when the content of partially saponified polyvinyl alcohol or completely saponified polyvinyl alcohol in the coating material was larger than the value in Example 3.

In Examples 1 to 3, partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol having respective average degree of polymerization and saponification rate was selected. There is no correlation in the relationship, and generally independent choices are possible.

Although a bar coater is selected as the recording means, the present invention is not limited to these recording means, and any of various general recording means such as a micro dispenser may be used. It goes without saying that the effects are similar. (Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4.

FIG. 1 is a block diagram showing the construction of the ink jet recording apparatus of the present invention. FIG. 2 is a schematic diagram of an inkjet recording apparatus according to the present invention. FIG. 3 is an explanatory diagram for explaining the relationship between the recording area and the coating area in the inkjet recording apparatus of the present invention. FIG. 4 is a timing chart for explaining the temporal relationship between the coating operation and the recording operation in the inkjet recording apparatus of the present invention. Further, the same reference numerals are used for the same portions in each drawing.

In FIG. 1, reference numeral 1 is a recording means, which is a known ink jet recording head. Reference numeral 2 denotes a delay means, which is composed of a FIFO (first-in first-out memory), a RAM (random access memory), a latch, or the like. The delay means 2 temporarily stores the input data and outputs it as needed. Reference numeral 3 is a coating means, which coats a recording medium with a coating material containing polyvinyl alcohol or the like according to a recording signal 51. The coating means 3 can be used for various inkjet recording heads such as an inkjet recording head using the vibration force of a piezoelectric element and a bubble jet head using film boiling.
In this embodiment, an on-demand type ink jet recording head is used.

In FIG. 2, reference numeral 14 is a recording medium,
It is a coated paper, a small amount of coated special paper, PPC paper, OHP film, or the like. A platen roller 15 is rotated by a motor or the like. Reference numeral 16 is a carrier, on which the coating means 3 and the recording means 1 are fixed. Reference numeral 17 is a lead screw, which scans the carrier 16 by rotating. Reference numeral 18 is a guide rail that slides the carrier 16. Reference numeral 19 denotes a housing in which the platen roller 15, the lead screw 17 and the like are arranged.

In FIG. 4, a position 57 indicates a position where the recording means 1 can record, and a numeral in the drawing indicates a column of pixels. Similarly, the position 58 is the coating means 3
Indicates the position where coating is possible, and the number indicates which column of pixels the pixel corresponds to. Further, in the case of the present embodiment, the recording means 1 precedes the coating means 3 in the main scanning direction of the arrow 104 by a distance corresponding to two pixels. In this case, the delay unit 2 delays the recording signal 51 until the coat unit 3 moves by two pixels in the main scanning direction of the arrow 104.

Next, the operation of this embodiment will be described with reference to FIGS. The platen roller 15 has an arrow 101.
By rotating in the direction of, the recording medium 14 wound around the platen roller 15 is transported in the direction of arrow 102. The platen roller 15 aligns the desired recording start position with the position of the recording unit 1 and temporarily stops the conveyance. In addition, the lead screw 17 is rotated to move the carriage 16 to the home position 105 to prepare for recording.

Recording is performed as follows. The recording signal 51 is input to the recording means 1 and the delay means 2. The recording unit 1 ejects recording ink onto the recording medium 14 in response to the recording signal 51. With this, the lead screw 17 rotates,
The carrier 16 includes a lead screw 17 and a guide rail 18.
It moves up in the main scanning direction of arrow 104. This allows
The recording unit 1 moves in the main scanning direction of the arrow 104,
Images such as characters, line drawings, and patterns are formed on the recording medium 14. The delay means 2 delays the recording signal 51 for a predetermined time and inputs the delayed signal 52 delayed to the coat means 3. The delay time depends on the recording position of the recording means 1 and the coating means 3.
It takes at least a time longer than the time required for the carrier 16 to move in order to adjust the coating positions. The coating unit 3 discharges the coating material according to the delay signal 52 to coat the image formed on the recording medium 14 with the recording ink.

The above recording operation will be described in more detail by taking the case of recording the letter T in FIG. 3 as an example.
It is assumed that one box in FIG. 3 corresponds to a pixel, which is the minimum unit of recording, and a case of recording and coating the second row 23 in the drawing on the recording medium will be described as an example.

The lead screw 17 has a driving clock 63.
And the carrier table 16 is moved by one pixel in one clock. When the drive clock 63 is input by one clock, the recording unit 1 moves to a position where the pixels in the first column can be recorded, but the recording signal 51 is a pulse because it is a pixel that does not record (second row, first column). Does not form. Recording means 1
Does not record according to the recording signal 51.

Next, when one clock is input, the recording means 1 moves to a position where the pixels in the second column can be recorded. At this time, since the recording unit 1 is on the pixel for recording, a pulse of the recording signal 51 is input to the recording unit 1 and recording is performed in an area corresponding to the pixel on the second row, second column on the recording medium. Ink is ejected to form an image.

Next, when one clock is input, the recording means 1 moves to a position where the pixels of the third column can be recorded, and the coating means 3 moves to a position where the pixels of the first column can be coated. At this time, since the recording unit 1 is on the pixel for recording, the pulse of the recording signal 51 is input to the recording unit 1,
The recording ink is ejected to form an image on a region corresponding to the pixel on the second row, third column on the recording medium. The delay signal 52 is a signal obtained by delaying the recording signal 51 by two clocks of the drive clock 63 and is LOW. The coating unit 3 does not coat the pixels in the first column according to the delayed signal 52.

Further, when one clock is input, the recording means 1 moves to a position where the pixels in the fourth column can be recorded, and the coating means 3 moves to a position where the pixels in the second column can be coated. At this time, since the recording unit 1 is on the pixel for recording, the pulse of the recording signal 51 is input to the recording unit 1 and for recording in the area corresponding to the pixel of the second row, fourth column on the recording medium. Ink is ejected to form an image. Further, the coating unit 3 discharges the coating material onto the pixels recorded with the recording ink in the second column to perform coating.

By repeating the above operation, recording and coating in the main scanning direction can be realized.
Then, when the operation in the main scanning direction is completed, the lead screw 17 is rotated in the opposite direction to that at the time of recording, the transport base 16 is moved to the home position 105, and the next recording is prepared. Further, the platen roller 15 is rotated in the direction of arrow 101, the coated medium 14 wound around the platen roller 15 is conveyed by one line in the direction of arrow 102, and recording is performed in the next main scanning direction.

Recording and coating are performed in one direction by repeating the above operation. At this time, after the recording with the recording ink is performed on the recording medium, the recording area can always be coated with the coating material. This makes it possible to realize stable, high-quality recording that is less likely to be affected by the storage state of the recording medium.

(Embodiment 5) A fifth embodiment of the present invention will be described with reference to FIGS. 5, 6, 7 and 8. FIG. 5 is a block diagram of another configuration of the inkjet recording apparatus of the present invention. FIG. 6 is another schematic view of the ink jet recording apparatus according to the present invention. FIG. 7 is an explanatory diagram for explaining the relationship between the recording area and the coating area in the inkjet recording apparatus of the present invention. FIG. 8 is a timing chart for explaining the temporal relationship between the coating operation and the recording operation in the inkjet recording apparatus of the present invention. Further, the same reference numerals are used for the same portions in each drawing.

In FIG. 5, the same pre-coating means 4 as the coating means 3 was used. In FIG.
The coating means 4 precedes the recording means 1 by a distance of one line in the sub-scanning direction of the arrow 107. Similarly, the recording unit 1 precedes the coat unit 3 by a distance of one line in the sub-scanning direction of the arrow 107.

In FIG. 8, a position 59 indicates a position where the pre-coating unit 4 can coat, a position 60 indicates a position where the recording unit 1 can record, and a position 61 indicates a position where the coating unit 3 can coat. In the figure, the tens place indicates the row and the ones place indicates the column. For example, 24 indicates that it corresponds to the pixel in the second row and the fourth column. Further, in the case of the present embodiment, the pre-coating means 4 precedes the recording means 1 by a distance corresponding to one line in the sub-scanning direction of the arrow 107. The recording signal 51 is delayed until it moves one line in the scanning direction. The delay unit 2 can cope with a delay of an arbitrary number of lines by increasing or decreasing the memory capacity.

Next, the operation of this embodiment will be described with reference to FIGS. The platen roller 15 has an arrow 101.
By rotating in the direction of, the recording medium 14 wound around the platen roller 15 is transported in the direction of arrow 102. It should be noted that the platen roller 15 aligns the desired recording start position with the position of the pre-coating means 4, and suspends the conveyance. In addition, the lead screw 17 is rotated to move the carriage 16 to the home position 105 to prepare for recording.

Recording is performed as follows. The recording signal 51 is input to the pre-coat means 4 and the delay means 2. The pre-coating means 4 coats the recording medium with a coating material according to the recording signal 51. Along with this, the lead screw 17 rotates, and the carrier 16 moves on the lead screw 17 and the guide rail 18 in the main scanning direction of arrow 104. As a result, the pre-coating means 4 has the arrow 10
The coating material is coated on the recording medium while moving in the main scanning direction 4. The delay means 2 delays the recording signal 51 by one line, and the delayed signal is the delayed signal 52. The recording means 1 has a delayed signal 5
The recording ink is ejected in accordance with No. 2 to record the recording medium 14
An image is formed on the top coating material. The image formed in this way is easily affected by moisture and light, and there is a high risk of degrading image quality. Therefore, this image is further coated by the coating means 3.

The above recording operation will be described in more detail by taking the case of recording the letter T in FIG. 7 as an example.
The pre-coating means 4 is present at a position where the first line can be coated, and the recording signal 51 is the pre-coating means 4.
Is input to the recording means 12. However, the recording signal 51 is always LOW because the first row is an area where recording is not performed, and the pre-coating means 4 does not perform coating. Further, the delay means 2 sequentially stores the input recording signal 51. This completes the first scan.

The lead screw 17 is rotated in the opposite direction to that at the time of recording, and the carrier 16 is moved to the home position 105. Further, the platen roller 15 is rotated in the direction of arrow 101, and the recording medium 14 wound around the platen roller 15 is conveyed by one line in the direction of arrow 102 to prepare for the next recording start.

The recording means 12 is at a position where the pre-coating means 4 can coat the second row and the recording means 12 is where the first row can be stored. The recording signal 51 is for recording the pixels of the second to seventh columns, and the pre-coating means 4
Is input to the delay means 2. The pre-coating unit 4 coats the positions corresponding to the pixels in the second to seventh columns with the coating material according to the recording signal 51. Also,
The delay unit 2 sequentially stores the input recording signal 51, and further sequentially outputs the data of the first row as the delay signal 52. The delay signal 52 is input to the recording means 12. The recording unit 12 ejects the recording ink in response to the delay signal 52, but when scanning in the preceding line, the delay unit 2 is all L
OW is written and no pulse is output. Therefore, the recording unit 1 does not eject ink. From the above, 2
After the second scanning is completed, the lead screw 17 is rotated in the opposite direction to that at the time of recording, and the carrier 16 is moved to the home position 105.
Move to. Further, the platen roller 15 is rotated in the direction of arrow 101, and the recording medium 14 wound around the platen roller 15 is conveyed by one line in the direction of arrow 102 to prepare for the next recording start.

The pre-coating unit 4 is in a position where the third line can be coated, the recording unit 1 is in a position where the second line can be stored, and the coating unit 3 is in a position where the first line can be coated. The recording signal 51 inputs pulses to the pre-coating means 4 and the delaying means 2 so as to record the pixels in the second to seventh columns. The pre-coat means 4 has a recording signal 51.
Accordingly, the coating material is coated on the positions corresponding to the pixels on the second to seventh columns. The delay signal 52 delayed by one line is input to the recording means 12. The recording unit 1 ejects the recording ink in response to the delay signal 52, but in the scanning in the previous line, the delay unit 2 performs recording at the positions corresponding to the pixels of the second to seventh columns. Since the data is stored, the recording unit 1 ejects ink to the positions corresponding to the pixels in the second to seventh columns. Therefore, it is possible to perform recording with the recording ink on the pixels coated in the scanning in the previous line. The overcoat means 4 coats the first row in accordance with the coat signal 53 which is the output signal of the delay means 2. The coat signal 53 is a signal for instructing the coat means 3 to coat the pixels from the first column to the last pixel, and coats all the recordable areas of the recording means 1. The actual operation timing is shown in FIG.

With the above, the third scanning is completed. The lead screw 17 is rotated in the opposite direction to that at the time of recording, and the carrier 16 is moved to the home position 105. Further, the platen roller 15 is rotated in the direction of arrow 101, and the recording medium 14 wound around the platen roller 15 is moved in the direction of arrow 1.
One line is conveyed in the direction 02 to prepare for the start of the next recording.

By repeating the above operation, as shown in FIG. 7, the recording material can be pre-coated with the coating material, and recording can be further performed with the recording ink to further coat the recorded image. The coating method is not limited to this. For example, even if the coating unit 3 has a lower resolution than the recording unit 1, the same effect can be obtained.

As a result, stable high-quality recording can be realized without being affected by the storage state of the recording medium. Further, as in the case of the fourth embodiment, it is possible to perform the coating by the coating means 3 only on the recorded pixels. Note that this embodiment is also compatible with bidirectional recording in the direction of arrow 104 and the opposite direction, and enables high speed printing.

In this embodiment, the description has been made by using the example of ink jet coating using a single color ink, but the effect of the present invention is also applicable to the ink jet coating using a multi color ink or a full color ink. Needless to say.

[0060]

As described above, after ink is deposited on the recording medium, the partially saponified polyvinyl alcohol having a saponification rate of 60 to 97.5% or the saponification rate of 97.
By coating with a coating material containing 5% or more of completely saponified polyvinyl alcohol, the storage state of the recording medium, such as writing with an aqueous pen, moisture of sweat or humidity, irradiation of light, external There is an effect that stable high-quality ink jet recording can be performed without being affected by scratches caused by a large impact.

Further, since the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol used in the present invention is a very inexpensive material, there is an effect that an inexpensive recording material can be provided.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an inkjet recording apparatus of the present invention.

FIG. 2 is a schematic diagram of an inkjet recording apparatus of the present invention.

FIG. 3 is an explanatory diagram illustrating a relationship between a coating area and a recording area by the inkjet recording apparatus of the present invention.

FIG. 4 is a timing diagram illustrating a temporal relationship between a coating operation and a recording operation by the inkjet recording apparatus of the present invention. .

FIG. 5 is a block diagram of another configuration in the inkjet recording apparatus of the present invention.

FIG. 6 is another schematic view of the inkjet recording apparatus of the present invention.

FIG. 7 is an explanatory diagram illustrating a relationship between a coating area and a recording area in the inkjet recording apparatus of the present invention.

FIG. 8 is a timing diagram illustrating a temporal relationship between a coating operation and a recording operation in the inkjet recording apparatus of the present invention. .

[Explanation of symbols]

 1 recording means 2 delay means 3 coating means 4 pre-coating means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location D21H 19/20 (72) Inventor Hiroshige Ikeno 6-31-1 Kameido, Koto-ku, Tokyo Seiko Denshi Industry Co., Ltd.

Claims (7)

[Claims] 1. A partially saponified polyvinyl alcohol having a saponification rate of 60 to 97.5% in a coating material to be coated after ink is deposited by inkjet recording on a recording medium used for inkjet recording, or A coating material containing completely saponified polyvinyl alcohol having a saponification rate of 97.5% or more. 2. The partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol contained has an average degree of polymerization of 150 to 750, and the content of the partially saponified polyvinyl alcohol or the fully saponified polyvinyl alcohol is 0. The coating material according to claim 1, which is 2 to 30%. 3. The partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol contained therein has an average degree of polymerization of 750 to 2000, and the content of the partially saponified polyvinyl alcohol or the completely saponified polyvinyl alcohol is 0. The coating material according to claim 1, which is 1 to 20%. 4. The partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol contained has an average degree of polymerization of 2000 to 5000, and the content of the partially saponified polyvinyl alcohol or the fully saponified polyvinyl alcohol is 0. The coating material according to claim 1, wherein the coating material is 05 to 15%. 5. An ink jet recording apparatus for recording an image on a recording medium by ejecting recording ink according to a recording signal, and then recording on the recording medium after the recording ink is recorded on the recording medium. The inkjet recording apparatus according to claim 1, further comprising a coating unit for coating the coating material on the substrate. 6. An ink jet recording apparatus for ejecting a recording ink according to a recording signal to record an image on a recording medium, wherein the recording ink is ejected according to a recording signal,
Recording means for recording an image on a recording medium, delay means for delaying the recording signal, and coating of the coating material on the recording medium after recording according to an output signal of the delay means. The inkjet recording apparatus according to claim 1, further comprising coating means. 7. An ink jet recording apparatus for recording an image on a recording medium by ejecting recording ink according to a recording signal, before recording on the recording medium by the recording ink. 7. The ink jet recording apparatus according to claim 5, further comprising means for coating the medium with the coating material.