JP4053722B2 - Image recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image recording apparatus, and more particularly to a recording medium pretreatment means effective for an inkjet image recording method. Specifically, before applying a pretreatment liquid for improving image quality. The present invention relates to an image recording apparatus provided with a treatment liquid coating apparatus.
[0002]
[Prior art]
In recent years, inkjet printers are rapidly spreading due to advantages such as low noise, low running cost, and easy colorization. However, when recorded on plain paper, in addition to initial quality problems such as bleeding, density, color tone, and show-through, there were problems related to image robustness such as water resistance and weather resistance. Proposals have been made.
[0003]
As a means for solving these problems, when an image is formed with ink, a recording material in which a material for fixing the dye in the ink is fixed on the surface of the recording material, such as plain paper, or a white pigment or the like on the surface. It is possible to use a recording material coated with a water-soluble polymer as disclosed in JP-A-56-86789, JP-A-55-144172, JP-A-52-53012, or JP-A-56-89594. No. gazette and the like. However, this method requires the purchase of special paper that has been pre-coated, so there is the inconvenience that it is not possible to freely use paper that is close to you, and there is a problem with the ease of writing with a pencil or pen. there were.
[0004]
JP-A-55-65269 discloses that ink permeability is improved by adding a surfactant to the ink in order to suppress bleeding at a color boundary such as a two-color overlapping portion. ing. This method is effective for resolving bleeding at the color boundary such as the two-color overlapped area and smearing (image contamination due to contact after printing) because the ink penetrates the recording paper at a high speed. The image cannot be resolved. Furthermore, a method of adding a volatile solvent to the ink is disclosed in Japanese Patent Application Laid-Open No. 55-66976. However, the same effect as that of the penetrating ink can be obtained, but the nozzle is easily clogged. In addition, in order to improve water resistance and light resistance, the use of ink containing a pigment as a colorant has also increased, but it is difficult to maintain the reliability around the nozzle such as clogging with an ink containing a pigment, Further, when high color reproducibility such as a photographic image or CG is required, there is a problem that cyan and magenta color development is insufficient and a satisfactory image cannot be obtained.
[0005]
In order to solve such problems, Japanese Patent Application Laid-Open No. 56-89595 discloses that a polymer solution such as carboxymethyl cellulose, polyvinyl alcohol, polyvinyl acetate or the like is previously sprayed on a recording material, and then the polymer solution. There has been proposed an ink jet recording method in which ink is ejected onto a portion where the ink adheres to perform printing. However, although this method can improve the sharpness of the printed image, it is not effective to improve the drying property of the printed image, and the effect of improving the image quality in the color image is not recognized so much. In addition, an ink jet recording method in which an image recording acceleration liquid containing a compound that insolubilizes the dye in the ink is deposited on a recording material by an ink jet method and then ink is ejected onto the portion where the image recording acceleration liquid is adhered to perform printing. Although disclosed in Japanese Laid-Open Patent Application No. 64-63185, Japanese Patent Application Laid-Open No. 8-20159, Japanese Patent Application Laid-Open No. 8-20161, etc., this method has a large amount of water adhering at the two-color overlapping portion. There is a problem that the bleeding of the ink cannot be sufficiently suppressed and the show-through of the ink is large. Furthermore, there is a problem that cockling (waving) of the recording material occurs. In addition, since the image recording acceleration liquid is sprayed with an inkjet head, there are restrictions on the viscosity and surface tension of the liquid in order to obtain stable injection, and there are restrictions on the nozzle diameter and composition of the liquid in order to prevent clogging. There was a problem that conditions were added and the degree of freedom was significantly reduced.
[0006]
As a method for solving this problem, a method of applying to the entire paper surface using a roller is disclosed in Japanese Patent Laid-Open No. 7-156538 (hereinafter referred to as a conventional example). FIG. 4 is a schematic cross-sectional view showing a configuration in which a coating material is applied to a recording medium using a conventional roller. In the figure, a recording medium 63 is wound around a platen roller 61 rotated by a motor or the like (not shown) with a presser chuck 62. A coating material 65 is accommodated in the coating unit 64, and the coating material 65 is thinned on the roller surface of the coating roller 69 by the stirring / supply roller 66 and the transport / thinning rollers 67, 68. The coating roller 69 is rotated while being pressed onto the recording medium 63 wound around the rotating platen roller 61, and the coating material 65 is applied to the surface of the recording medium 63. At the same time, the inkjet head 70 performs recording by discharging ink onto the surface of the recording medium 63 coated with the coating material 65. As described above, according to the conventional method in which the pretreatment liquid for improving the image quality is previously applied to the recording area by the application roller, the liquid having a relatively high viscosity is thinly applied as compared with the method of spraying using the ejection head. It is excellent in that image bleeding and color bleeding can be further reduced.
[0007]
[Problems to be solved by the invention]
However, according to the above conventional example, the driving of the conveying roller and the coating roller for conveying the recording medium according to the main scanning which is the recording scanning is interlocked, so that the coating roller is pressed by the platen roller even during the recording scanning. During the main scan, which is the recording scan, the rotation of the coating roller is interrupted and the coating roller is stopped while being pressed against the recording medium, and the coating material is concentrated and applied to a part of the recording medium during the stop. It becomes. For this reason, there has been a problem that coating unevenness is generated, and undulation and image quality unevenness occur.
[0008]
The present invention is for solving such problems, and the application conditions by the application roller are always kept constant, there is no waviness or image quality unevenness due to application unevenness, and excellent reproducibility of fine lines and the like at color boundaries. It is an object of the present invention to provide an image recording apparatus capable of continuously and stably obtaining an image having excellent image quality with good color tone without blurring and excellent water resistance.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a pretreatment liquid application means having a coating roller for applying the pretreatment liquid to the recording region of the recording medium, the image pretreatment liquid to record an image on a recording area of the coated recording medium and a recording unit, according to the image recording apparatus according to the present invention, conveying the recording medium which is applied by the preprocessing liquid application means to the image recording unit, a conveying row La driven independently of the drive of the application roller coating A slack space for loosening the recording medium is provided between the roller and when the average transport speed of the transport roller is higher than the average transport speed of the coating roller, only the coating roller is driven to put a predetermined amount of the recording medium in the slack space. It is characterized in that the driving of the conveying roller is started after the slackening. Therefore, even in intermittent transport in the printing, coating roller so rotated at a constant speed in the conveying rows La and another drive for conveying the recording medium to the image recording means, without wavy or uneven image quality due to uneven coating, coating by a coating roller Conditions can always be kept constant. If it is strong, an image with excellent reproducibility of fine lines and the like, excellent image quality with excellent color tone without blurring at the color boundary, and excellent water resistance can be obtained stably. Further, the difference in the conveyance distance of the recording medium, which is the difference between the printing speed and the pretreatment liquid application speed, can be absorbed in the slack space.
[0010]
The pretreatment liquid is a liquid containing a solvent that disperses or dissolves the colorant in the recording liquid and a compound that insolubilizes the colorant .
[0011]
Further, the conveyance rollers form a pair of conveyance rollers , and the conveyance rollers are started to drive after the leading edge of the recording medium abuts against the conveyance roller pair for a predetermined time to loosen the recording medium by a predetermined amount in the slack space. Therefore, the entire apparatus can be configured compactly.
[0013]
Further, a sensor for detecting the leading edge of the recording medium on the downstream side of the coating roller, when the average conveyance speed of the conveyance row La is larger than the average transport speed of the application roller, the tip of the applying roller only is driven, the sensor recording medium and detecting, by initiating the drive of the conveying roller to the recording medium after the detection constant at between slack for Mi space after a predetermined amount slackened, the conveyance of the recording medium is a difference in printing speed and the pretreatment liquid application speed The difference in distance can also be absorbed in the slack space for the recording medium.
[0014]
Further, if the average conveying speed of the coating roller is V2, the time required for image recording is t, and the length in the longitudinal direction of the recording medium is L, the predetermined amount for loosening the recording medium in the slack space is V2 × t and L By setting it to be greater than or equal to the difference, the recording medium can be stored in the slack space.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
According to the image recording apparatus according to the present invention, the pretreatment liquid recording medium that has been applied by the coating means is conveyed to the image recording means, between the transport row La and the application roller to be driven independently of the drive of the application roller, When a slack space for loosening the recording medium is provided, and the average transport speed of the transport roller is larger than the average transport speed of the coating roller, the transport roller is driven after the recording medium is slackened to a slack space by driving only the coating roller. Start driving. Therefore, even in intermittent transport in the printing, coating roller so rotated at a constant speed in a different drive and conveying rows La, no wavy and uneven image quality due to uneven coating can be kept always constant coating conditions by the coating roller . Further, the difference in the conveyance distance of the recording medium, which is the difference between the printing speed and the pretreatment liquid application speed, can be absorbed in the slack space.
[0016]
【Example】
FIG. 1 is a sectional view showing the structure of an image recording apparatus according to the first embodiment of the present invention. In FIG. 1, the image recording apparatus 1 of this embodiment mainly includes a paper supply unit 10, a pretreatment liquid application unit 20, and an image recording unit 30. The paper supply unit 10 includes a paper supply roller 12 that sends out the paper 11. The pretreatment liquid application unit 20 contains a pretreatment liquid 22 that contains a pretreatment liquid 22 that is a liquid containing a colorant and a compound that insolubilizes the colorant in a recording liquid composed of a solvent that disperses or dissolves the colorant. The tank 21, a pumping roller 23 that stirs and pumps the pretreatment liquid 22, a film thickness control roller 24 that controls the pumped pretreatment liquid to a uniform film thickness, and a coating roller 25. A counter roller 26 for applying the pretreatment liquid 22 to the sheet 11 is included. The image recording unit 30 includes transport rollers 31 to 33 that transport the transported paper 11 to a recording area of the recording head 36 described later, and a recording head 37 mounted on a carriage 35 that moves along the guide rod 34. And a discharge section 38 to 41 for discharging the recorded paper 11.
[0017]
Next, a series of image recording operations in the image recording apparatus 1 of the present embodiment having such a configuration will be described.
The paper 11 stored in the paper feed unit 10 is sent out by a paper feed roller 12. On the other hand, the pretreatment liquid 22 in the pretreatment liquid tank 21 of the pretreatment liquid coating unit 20 is pumped up by the pumping roller 23, and is controlled to have a uniform film thickness on the roller surface of the coating roller 25 by the film thickness control roller 24. . Then, the pretreatment liquid 22 is uniformly and thinly applied to the recording area of the paper 11 by the application roller 25 and the counter roller 26. The recording area of the paper 11 is sent to a recording area where the recording head 37 is provided by the conveying rollers 43 and 44 and the conveying rollers 31 to 33 while the pretreatment liquid 22 is applied by the pretreatment liquid application unit 20. Thereafter, the carriage 35 reciprocates along the guide rod 34 based on the image signal, and recording is sequentially performed on the recording area of the paper 11 on which the pretreatment liquid 22 is applied by the recording head 37 mounted on the carriage 35 and discharged. It is discharged to a discharge portion by rollers 38-41.
[0018]
Here, according to the image recording apparatus 1 of the present embodiment, printing is performed by the reciprocating operation of the recording head 37 mounted on the carriage 35 as described above, while the paper 11 is stopped at the recording scanning unit. Retained. After the reciprocating operation of the carriage 35, the carriage 35 is transported by a certain amount to be broken. For this reason, the sheet behavior is intermittent conveyance, and repeats from stop to conveyance (line feed) during printing. The average speed (= printing distance / printing time) of the paper 11 during printing is V1, and the conveying speed of the application roller 25 is V2. Hereinafter, the operation will be described in accordance with FIG. 2 and FIG. 3 showing operation time charts for the case of V1 <V2 and the case of V1> V2.
[0019]
First, when V1 <V2, when a print command is issued (time t ₀ ), the paper 11 separated and conveyed one by one by the paper feed roller 12 is between the application roller 25 and the counter roller 26 driven at a constant speed V2. Is conveyed while the pretreatment liquid 22 is applied (time t ₁ ). When the paper is further conveyed between the guide plates 27 and 28, the leading edge of the sheet is bent along the curved line of the guide plate 28, and is guided to the nip of the conveying rollers 43 and 44 as indicated by solid line arrows in FIG. . Then, the conveyance rollers 43 and 44 are driven to convey the sheet to the recording scanning unit (time t ₂ ). The conveyance speed V1 of the conveyance rollers 43 and 44 is set to be smaller than V2 by driving separately from the application roller 25. Further, when the leading edge of the sheet reaches the recording scanning unit and printing starts, the above-described intermittent conveyance is performed (time t ₃ ). The transport rollers 43 and 44 are transported at the same speed as the transport rollers 31 to 33, 38, and 39 of the recording scanning unit. Since the average transport speed during printing is slower than the transport speed of the application roller 25, the paper 11 sags in the space provided in the guide plate 27 and increases as printing is performed (indicated by the broken line in FIG. 1). When the length of the sheet is L, the time is t, and printing is required, the sheet 11 is fed out from the application roller 25 by an amount of V2 × t. For this reason, if the slack space of the paper 11 is set to be equal to or greater than the difference between V2 × t and L, the entire length of the paper 11 can be accommodated in the space of the guide plate 27. That is, even if the full length of the paper 11 is conveyed, the slack of the paper 11 does not exceed the guide plate 27.
[0020]
Next, when V1> V2, when a print command is issued (time t ₀ ), the paper 11 separated and conveyed one by one by the paper feed roller 12 is applied at a constant speed V2 and the application roller 25 and the counter roller 26. The pretreatment liquid 22 is conveyed while being applied (time t ₁ ). When the paper is further conveyed between the guide plates 27 and 28, the leading edge of the sheet is bent along the curved line of the guide plate 28, and is guided to the nip of the conveying rollers 43 and 44 as indicated by solid line arrows in FIG. . The transport rollers 43 and 44 are stopped and held for a while even if the leading edge of the sheet reaches the nip. For this reason, the sheet 11 is slack in the space portion of the guide plate 27 as shown by the broken line in FIG. The transport rollers 43 and 44 are driven separately from the application roller 25 after a predetermined time T (time t ₃ ) from when the sensor 29 provided on the downstream side of the application roller detects the leading edge of the paper (time t ₂ ), and is larger than V2. It is driven to rotate at the conveyance speed. By satisfying such a rotation start timing, the sheet slack is controlled to a constant amount. When the leading edge of the sheet reaches the recording scanning unit by the rotation of the conveying rollers 43 and 44 and printing starts, the above-described intermittent conveyance is performed (time t ₄ ). The conveyance rollers 43 and 44 are driven and driven at the same speed as that of the recording scanning unit. Since the average conveyance speed during printing is faster than the conveyance speed of the application roller 25, the above-mentioned sheet sag decreases as printing is performed. When the length of the sheet is L, the time is t, and printing is required, the sheet 11 is fed out from the coating roller by an amount of V2 × t. This amount is smaller than the paper length L. If the slack space of the paper is set to be equal to or larger than the difference between V2 × t and L, even if the paper is transported over the entire length, the slack does not disappear and the difference in transport speed between the two can be absorbed. The conveyance roller 43 is formed of a member having a low friction coefficient, such as metal, so that the leading edge of the sheet is along the nip between the rollers 43 and 44. If the parallelism accuracy of the transport rollers 43 and 44 with the recording scanning unit is ensured, the leading edge of the sheet can be guided in parallel to the recording scanning unit, and good skew correction can be performed.
[0021]
In this embodiment, the configuration of the transport roller is only the transport rollers 43 and 44, but it may be provided between them and is not limited to this. Further, the recording method is not limited to the ink jet method described here. Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and substitutions are possible as long as they are described in the scope of the claims.
[0022]
【The invention's effect】
As described above, a pretreatment liquid application means having a coating roller for applying the pretreatment liquid to the recording region of the recording medium, and image recording means for pre-treatment liquid for recording an image on a recording area of the coated recording medium the a, according to the image recording apparatus according to the present invention, conveying the recording medium which is applied by the preprocessing liquid application means to the image recording unit, the conveying row La and the application roller to be driven independently of the drive of the application roller A slack space for loosening the recording medium is provided between them. When the average transport speed of the transport roller is higher than the average transport speed of the coating roller, only the coating roller is driven to loosen the recording medium by a predetermined amount in the slack space. It is characterized in that driving of the conveying roller is started later. Therefore, even in intermittent transport in the printing, coating roller so rotated at a constant speed in the conveying rows La and another drive for conveying the recording medium to the image recording means, without wavy or uneven image quality due to uneven coating, coating by a coating roller Conditions can always be kept constant. If it is strong, an image with excellent reproducibility of fine lines and the like, excellent image quality with excellent color tone without blurring at the color boundary, and excellent water resistance can be obtained stably. Further, the difference in the conveyance distance of the recording medium, which is the difference between the printing speed and the pretreatment liquid application speed, can be absorbed in the slack space.
[0023]
The pretreatment liquid is a liquid containing a solvent that disperses or dissolves the colorant in the recording liquid and a compound that insolubilizes the colorant .
[0024]
Further, the conveyance rollers form a pair of conveyance rollers , and the conveyance rollers are started to drive after the leading edge of the recording medium abuts against the conveyance roller pair for a predetermined time to loosen the recording medium by a predetermined amount in the slack space. Therefore, the entire apparatus can be configured compactly.
[0026]
Further, a sensor for detecting the leading edge of the recording medium on the downstream side of the coating roller, when the average conveyance speed of the conveyance row La is larger than the average transport speed of the application roller, the tip of the applying roller only is driven, the sensor recording medium and detecting, by initiating the drive of the conveying roller to the recording medium after the detection constant at between slack for Mi space after a predetermined amount slackened, the conveyance of the recording medium is a difference in printing speed and the pretreatment liquid application speed The difference in distance can also be absorbed in the slack space for the recording medium.
[0027]
Further, if the average conveying speed of the coating roller is V2, the time required for image recording is t, and the length in the longitudinal direction of the recording medium is L, the predetermined amount for loosening the recording medium in the slack space is V2 × t and L By setting it to be greater than or equal to the difference, the recording medium can be stored in the slack space.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an image recording apparatus according to the present invention.
FIG. 2 is a time chart showing an image recording control operation in the first embodiment of the present invention.
FIG. 3 is a time chart showing an image recording control operation in the second embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view showing a configuration of a pretreatment liquid application unit in a conventional example.
[Explanation of symbols]
1; image recording apparatus; 10; paper supply unit;
11; paper, 12; paper feed roller, 20; pretreatment liquid application unit,
21; Pretreatment liquid tank, 22; Pretreatment liquid, 23; Pumping roller,
24; film thickness control roller; 25; coating roller; 26; counter roller;
27, 28; guide plate, 29; sensor, 30; image recording unit,
31-33, 43, 44; conveying roller, 34; guide rod,
35; carriage, 36; recording unit, 37; recording head,
38-41; discharge roller, 42; blade.

Claims (6)

Image recording with a pretreatment liquid application means having a coating roller for applying the pretreatment liquid to the recording region of the recording medium, and image recording means for the pre-treatment liquid for recording an image on a recording area of the coated the recording medium In the device
Between the front said recording medium which is applied by the treatment liquid application unit and conveyed to the image recording means, wherein the application roller and the conveying rows La driven independently of the drive of the application roller, the slack to slack recording medium Space for
When the average conveying speed of the conveying roller is larger than the average conveying speed of the applying roller, the driving of the conveying roller is started after the recording medium is loosened by a predetermined amount in the slack space by driving only the applying roller. An image recording apparatus. 2. The image recording apparatus according to claim 1 , wherein the pretreatment liquid is a liquid containing a solvent that disperses or dissolves the colorant in the recording liquid and a compound that insolubilizes the colorant . The conveyance roller forms a conveyance roller pair, and after driving the conveyance roller pair after the leading edge of the recording medium abuts against the conveyance roller pair for a predetermined time to loosen the recording medium in the slack space by a predetermined amount. the image recording apparatus according to claim 1 or 2, characterized in. A sensor for detecting the leading end of the recording medium on the downstream side of the coating roller, when the average conveyance speed of the conveyance row La is larger than the average transport speed of the coating roller, is driven only the application roller, said sensor by detecting the leading end of the recording medium, to claim 1 or 2, wherein said initiating a drive of the conveying roller after the recording medium after the detection constant time between before Kiyurumi space was predetermined amount slackened The image recording apparatus described. The pretreatment coating means, an image recording apparatus according to any one of claims 1-4, characterized in that it comprises a counter roller opposing the application roller. The average conveying speed of the applying roller V2, the time required for image recording t, when the longitudinal length of the recording medium is L, a predetermined amount of slack of the recording medium to the slack space is, V2 × t The image recording apparatus according to claim 1, wherein the image recording apparatus is set to be equal to or greater than a difference between L and L.

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