JP2006272731A - Inkjet recording apparatus and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide inkjet recording apparatus and recording method wherein inkjet recording images of a high quality is obtained by heating which does not need high temperatures and high energy. <P>SOLUTION: The inkjet recording apparatus 10 has an infrared heater 12 of 60W or lower set in a head carriage part 22 so as to be in non-contact with a printing face of a recording medium 11. In the recording method, the printing face is heated by using the infrared heater of an input energy of 60W or lower set in the head carriage part so as to be in non-contact with the printing face of the recording medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method. According to the present invention, drying of ink can be promoted by heating assist on the surface of a recording medium, and a high-quality inkjet recording image can be obtained.

  The ink jet recording method is a printing method in which printing is performed by ejecting ink droplets from a printer head and landing on a recording medium such as paper. The ink used in this ink jet recording method needs to have low viscosity in order to fly from the printer head, and ink with a high water content is used. Accordingly, problems of the ink jet recording method include occurrence of feathering, bleeding, decrease in density, decrease in color developability, decrease in fixability (dryability), and occurrence of cockling and curling. . A number of heat drying methods have been proposed as a means for solving such drawbacks.

  For example, an ink jet printer has been proposed in which a heater is mounted on a head carriage, and a printing surface is heated and dried by a pressure roller while printing (Patent Document 1). However, in this printer, since the pressure roller comes into contact with the printing surface immediately after printing, there is a possibility that contamination occurs before drying.

  Further, an ink jet printer that promotes evaporation by arranging a bar-shaped halogen heater on the back side of the printing surface has been proposed (Patent Document 2). In this printer, a quick start is possible by using a halogen heater, but for the purpose of completely evaporating the liquid component of the ink, an energy of about 200 W is added on average to heat it to a paper surface temperature of 200 ° C. Heat. Therefore, the ambient temperature rises, and even the ink in the printer head dries and causes clogging, and adverse effects due to the temperature rise of each part occur. Therefore, a heat exhaust mechanism for the printer is required. Will bring up costs and size.

  Furthermore, an inkjet printer that arranges and heats an infrared heater having a specific peak waveform on the back surface of the conveyance path has been proposed (Patent Document 3). In this printer, in order to increase the efficiency of the infrared heater, the heater surface and the paper surface are set to a short distance of 0.35 mm, and since the heater becomes as high as 170 ° C., paper dust falls from the back side of the paper and ignites. There is even a danger. Further, since heating is performed from the back side of the printing surface, not only the drying efficiency is poor, but also the printer head is constantly exposed to hot air, which causes clogging.

JP 2004-142385 A Japanese Patent Laid-Open No. 10-86353 JP-A-10-323974

Among the heat drying methods conventionally proposed in the ink jet recording apparatus, there has been no practical use including the apparatuses described in Patent Documents 1 to 3. The reason is that, in order to solve the above-mentioned various problems that the ink jet recording method has, the goal was to evaporate all or almost all liquid components such as water in the ink. In addition, a large amount of heat and a heater for that purpose are required, which creates new problems.
On the other hand, the present inventor has found that the above-mentioned various problems of the ink jet recording method can be substantially solved if the paper surface temperature rises from room temperature to about 10 to 20 ° C. at most. It was. Accordingly, by providing a heating means capable of raising the paper surface temperature from room temperature by about 10 to 20 ° C., that is, a heating assist means or a drying assist means, the above-mentioned various problems of the ink jet recording method are present. In addition, there are no disadvantages due to the provision of heating means. Further, the present inventor has also found that this effect is particularly remarkable in a low water-absorbing recording medium (for example, coated paper for printing).
The present invention is based on these findings.

The above-described problem can be solved by an ink jet recording apparatus in which an infrared heater of 60 W or less is arranged in a head carriage portion so as to be in a non-contact state with a printing surface of a recording medium according to the present invention.

In a preferred aspect of the apparatus of the present invention, a plurality of the infrared heaters are arranged at the front end portion and the rear end portion with respect to the main scanning direction of the head carriage portion.
In another preferable aspect of the device of the present invention, the sum of the plurality of input energies of the infrared heater is 60 W or less.
In still another preferred embodiment of the apparatus of the present invention, the infrared heater is a halogen lamp.
In still another preferred embodiment of the device of the present invention, the infrared heater is disposed at a distance of 20 mm or more from the printing surface of the recording medium.

  According to another aspect of the present invention, there is provided an ink jet recording method characterized in that the print surface is heated using an infrared heater having an input energy of 60 W or less arranged in the head carriage so as to be in a non-contact state with the print surface of the recording medium. Also related.

In a preferred embodiment of the method of the present invention, the irradiation range of the infrared heater is removed to the outside of the recording medium for each print scanning pass. In the preferred embodiment, when the irradiation range of the infrared heater is removed to the outside of the recording medium, control is performed to reduce the heating energy.
In another preferred embodiment of the method of the present invention, the upper limit of the surface temperature of the recording medium is set to a temperature 20 ° C. higher than room temperature.
In another preferred embodiment of the method of the present invention, a low water-absorbing recording medium is used.
In still another preferred embodiment of the method of the present invention, the low water-absorbing recording medium is a recording medium having a water absorption of 6 mL / m ² or less from the start of contact to 20 msec ^1/2 in the Bristow method.

According to the present invention, the printing surface can be heated without contact with the printing surface and directly from the printing surface side instead of from the back surface side, and further, high temperature and high energy are not required, so that the printer head can be heated. Without being exposed, various problems of the ink jet recording method can be solved and a high quality ink jet recorded image can be obtained.
In particular, when applied to a low-water-absorbing recording medium (for example, a coated paper for printing), the above-mentioned effect appears remarkably.

One embodiment of the device of the present invention is shown in FIG.
FIG. 1 is a partial perspective view of an ink jet recording apparatus 10 according to the present invention, and particularly shows the structure of a printing unit 2. The printing unit 2 includes, for example, a carriage 22 on which an ink cartridge is placed, a recording head 24 that ejects ink, a shaft hole 26 provided in the carriage 22, and a shaft hole 26 that passes through the carriage 22 in the feeding direction (FIG. 1). The guide shaft 28 is slidably supported in a direction (in the direction of arrow Y in FIG. 1) substantially perpendicular to the direction of the arrow X in FIG. The recording head 24 has a plurality of ink ejection openings arranged along the feeding direction of the recording medium 11. The printing unit 2 further includes a timing belt 32, a carriage motor 34, a black ink cartridge 36, and a color ink cartridge 38. The ink jet recording apparatus 10 according to the present invention further includes an infrared heater 12 in the carriage 22. The recording medium 11 is conveyed by a conveyance roller (not shown) and the discharge roller 5.

  When the carriage motor 34 drives the timing belt 32, the carriage 22 is guided by the guide shaft 38 and is substantially perpendicular to the feeding direction of the recording medium 11 (the direction of the arrow X in FIG. 1) (the arrow in FIG. 1). Reciprocate in the Y direction). A recording head 24 including a black ink discharge port and a color ink discharge port is mounted on the side of the carriage 22 facing the recording material. A black ink cartridge 36 and a color ink cartridge 38 for supplying ink to the recording head 24 are detachably mounted on the carriage 22.

  In the ink jet recording apparatus 10 shown in FIG. 1, printing is performed by sliding the carriage 22 in a direction (in the direction of arrow Y in FIG. 1) substantially perpendicular to the feeding direction (in the direction of arrow X in FIG. 1). If it does, since the infrared heater 12 will also slide at the same time with the slide movement of the carriage 22, if the infrared heater 12 is turned on, the printing part of the recording medium 11 will be heated and drying will be accelerated | stimulated.

  In the ink jet recording apparatus of the present invention, a plurality of the infrared heaters can be arranged at the front end portion and the rear end portion of the head carriage portion. This embodiment is schematically shown in FIG. FIG. 2 is a schematic front view showing only the head carriage portion 2 (2A, 2B, 2C) and the recording medium 11. The head carriage portion 2 (2A, 2B, 2C) has a front end portion and a rear end portion. Each has one infrared heater 12A, 12B. When a plurality of infrared heaters are provided in the head carriage portion, it is preferable to provide them symmetrically with respect to the feeding direction (the direction of arrow X in FIG. 1) as shown in FIG. This is because if the infrared heater is only on one side, during the reciprocating printing, the case where the infrared heater hits before ink hits and the case where it hits after landing occurs, and there is a difference in ink absorption and drying. It is for preventing. Therefore, when a plurality of the infrared heaters are provided, it is preferable to adjust the heating conditions so that the left and right heating conditions are the same. Note that the three types of head carriage portions 2A, 2B, and 2C shown in FIG. 2 will be described later.

  The input energy of the infrared heater provided in the ink jet recording apparatus of the present invention is 60 W or less, preferably 50 W or less. In the present invention, it is sufficient that the infrared heater can perform a simple heating assist function, and therefore it is not necessary to provide an infrared heater exceeding 60 W. In addition, if an infrared heater exceeding 60 W is provided, there is a problem that the cost for heat dissipation is required and the printer size is increased.

  When a plurality of infrared heaters are provided in the head carriage portion, the sum of the total input energy is preferably 60 W or less, more preferably 50 W or less. For example, a halogen lamp or a heating halogen lamp can be used as the infrared heater. A far-infrared heater (for example, a ceramic heater) can also be used as the infrared heater. It is preferable to use a halogen lamp because the response is quick, quick start is possible, and control is easy.

  In the ink jet recording apparatus of the present invention, the infrared heater is disposed at an interval of 20 mm or more (preferably 30 to 45 mm) from the printing surface of the recording medium. If the distance to the printing surface is less than 20 mm, ink mist adhesion may increase.

  The ink jet recording method of the present invention can be carried out, for example, using the ink jet recording apparatus of the present invention. Since the heating in the ink jet recording method according to the present invention is merely drying assistance, the upper limit of the heating surface temperature of the recording medium is preferably a temperature 20 ° C. higher than room temperature (for example, 25 ° C.), more preferably 15 ° C. higher than the room temperature. It is sufficient that the temperature is more preferably 10 ° C. higher than room temperature. When heating to a temperature higher than 20 ° C. above room temperature, problems arising from the provision of heating means (for example, drying of ink in the printer head due to an increase in ambient temperature and generation of harmful effects due to a temperature increase of each component) appear. The lower limit of the heating surface temperature of the recording medium is not particularly limited, but is, for example, a temperature 5 ° C. higher than room temperature.

  In the ink jet recording method of the present invention, it is preferable to remove the irradiation range of the infrared heater to the outside of the recording medium for each printing scan pass. Here, to remove the irradiation range of the infrared heater to the outside of the recording medium means to move to the outside of the recording medium 11 as in the head carriage part 2A and the head carriage part 2B shown in FIG. In order to irradiate heat energy evenly to the recording medium, if the irradiation area of the infrared heater always goes out of the recording medium and does not reciprocate, the end of the recording medium has a longer heating time than the central part. This is to prevent this from happening. In the head carriage portion 2C shown in FIG. 2, the irradiation range of the infrared heater is on the recording medium 11.

  In the inkjet recording method of the present invention, when the irradiation range of the infrared heater is removed outside the recording medium as described above, the control for reducing the heating energy when the irradiation range of the infrared heater is removed outside the recording medium. It is preferable to carry out. That is, in the reciprocating motion of the head carriage portion, it is preferable to perform control to reduce the heating energy when changing the direction. In general, a non-printing portion of an ink jet recording apparatus has an ink flushing position and is equipped with a cap and an ink absorbing material. Heat energy is accumulated by repeated reciprocation of the head carriage portion. This is because when they are heated, harmful effects occur. Note that, when the halogen lamp is turned on / off, the lifetime is extremely reduced. Therefore, it is preferable to reduce the influence of heating on the portion other than the recording medium as much as possible by applying current control to reduce the current at a position away from the recording medium.

When the ink jet recording method of the present invention is carried out using a low water-absorbing recording medium, the effect of heat assist can be remarkably obtained. The low-absorbency recording medium is, for example, a recording medium having a water absorption of 6 mL / m ² or less from the start of contact to 20 msec ^1/2 in the Bristow method.

  The Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (J'TAPPI). The details of the test method are described in J'TAPPI No. 51, “Method for testing liquid absorbency of paper and paperboard”. During measurement, the head box slit width of the Bristow test is adjusted according to the surface tension of the ink. Also, the point where the ink is removed from the back of the paper is excluded from the calculation.

FIG. 3 is a graph showing the results of measuring the water absorption of four types of paper by the Bristow method by the Japan Paper Pulp Technology Association. As described in the reference examples described later, the line a is a coated paper for printing (trade name = OK top coat N; manufactured by Oji Paper Co., Ltd .; hereinafter, “OKTN” is used as an abbreviation), and the line b is a high-quality PPC. Paper (product name = BM paper; manufactured by Nippon Paper Industries Co., Ltd.), line c is another PPC paper (product name = Xerox Premium Multipurpose 4024; manufactured by Xerox Corporation; hereinafter, “4024” is used as an abbreviation), and line d is , Inkjet exclusive paper (trade name = super fine paper; manufactured by Seiko Epson Corporation; hereinafter, “SF paper” is used as an abbreviation) is shown.
Further, in the present specification, "contact water absorption from the start until 20 msec ^1/2 is 6 mL / ^{m 2} or less" is "20" from the "0" ^{msec 1/2} of the horizontal axis of FIG. 3 ^{msec 1/2} This means that the cumulative volume of water absorbed within the time period up to (that is, 0.4 sec: 20 msec ^1/2 = 400 msec = 0.4 sec) does not exceed “6” mL / m ² on the vertical axis. That is, low water-absorbing paper is used.

  As is clear from FIG. 3, the only paper that satisfies the requirements for low water absorption defined in this specification is coated paper for printing (OKTN: line a), and other PPC paper (lines b, c) and None of the inkjet paper (SF paper: line d) satisfies the requirement of low water absorption.

  In the ink jet recording method of the present invention, as long as it is a low water-absorbing recording medium, in particular, a recording medium that satisfies the above-mentioned low water-absorbing requirements, letterpress printing, flat printing (for example, offset printing), or Any coated paper used as printing paper for intaglio printing (for example, gravure printing) can be used. The coated paper includes ordinary coated paper, cast coated paper, and matte coated paper.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.

<Example 1>
A printing experiment was conducted by attaching a 50 W small halogen lamp (JCR3551; manufactured by Iwasaki Electric Co., Ltd.) to the head carriage portion of an inkjet printer (PX-G900; manufactured by Seiko Epson). As the recording medium, the coated paper for printing described in Reference Examples (trade name = OK topcoat N; manufactured by Oji Paper Co., Ltd .; abbreviation = OKTN) was used. The amount of water absorbed from the start of contact by the Bristow method of this coated paper for printing to 20 msec ^1/2 was 6 mL / m ² . The ink set used was an aqueous pigment ink set (ink set for PX-G4000; manufactured by Seiko Epson) of four colors (cyan, magenta, yellow, and black).
At the power input shown in Table 1 (“W” in Table 1), the color bleed determination pattern is printed at various duty intervals of 4%, and the maximum duty value that color bleed can tolerate (that is, bleeding between colors). Was measured). The results are shown in Table 1.

As is apparent from Table 1, the duty was improved by about 12% at 50W. The temperature of the printed surface at this time was 35 ° C., and was room temperature (25 ° C.) + 10 ° C.
If the temperature is about + 10 ° C., the environment in the printer is also within the normal use conditions, so that there is little adverse effect on the clogging of the head and ink evaporation at the flushing point. That is, 60 W or less, preferably 50 W or less is preferable.

<Reference example>
The water absorption of four types of paper was measured by the Bristow method by the Japan Paper Pulp Technology Association. As paper, coated paper for printing (trade name = OK top coat N; manufactured by Oji Paper Co., Ltd .; abbreviation = OKTN), high-quality PPC paper 1 (trade name = BM paper; manufactured by Nippon Paper Industries Co., Ltd.), PPC paper 2 (Trade name =: Xerox Premium Multipurpose 4024; manufactured by Xerox Corporation; abbreviation = 4024) and inkjet paper (trade name = super fine paper; manufactured by Seiko Epson Corporation; abbreviation = SF paper) were used. The absorption performance of the paper was measured using an automatic scanning absorption meter by the Bristow method.
The measurement results are shown in FIG. In FIG. 3, line a is coated paper for printing (OKTN), line b is high-quality PPC paper 1 (BM paper), line c is PPC paper 2 (4024), and line d is ink jet dedicated paper (4024). (SF paper) results are shown.

  According to the ink jet recording apparatus and the ink jet recording method of the present invention, drying of the print surface is assisted, so that a high quality ink jet recorded image can be obtained. In particular, it can be used particularly effectively in ink jet recording of low water-absorbing recording media (for example, coated paper for printing).

1 is a partial perspective view of an ink jet recording apparatus according to the present invention. FIG. 3 is a schematic front view showing only a head carriage section and a recording object. It is a graph which shows the result of having measured the water absorption of 4 types of paper by Bristow method.

Explanation of symbols

2 ... printing section; 5 ... discharge roller;
DESCRIPTION OF SYMBOLS 10 ... Inkjet recording apparatus; 11 ... Recording medium;
12, 12A, 12B, 12C ... infrared heaters;
22 ... carriage; 24 ... recording head;
26 ... shaft hole; 28 ... guide shaft;
32 ... Timing belt; 34 ... Carriage motor;
36 ... Black ink cartridge;
38: Color ink cartridge.

Claims (11)

  An inkjet recording apparatus, wherein an infrared heater of 60 W or less is disposed in a head carriage portion so as to be in a non-contact state with a printing surface of a recording medium.   The inkjet recording apparatus according to claim 1, wherein a plurality of the infrared heaters are arranged at a front end portion and a rear end portion with respect to a main scanning direction of the head carriage portion.   The inkjet recording apparatus according to claim 2, wherein a sum of a plurality of input energies of the infrared heater is 60 W or less.   The inkjet recording apparatus according to claim 1, wherein the infrared heater is a halogen lamp.   The inkjet recording apparatus according to any one of claims 1 to 4, wherein the infrared heater is disposed at a distance of 20 mm or more from a printing surface of a recording medium.   An ink jet recording method, comprising: heating a print surface using an infrared heater having an input energy of 60 W or less arranged in a head carriage so as to be in a non-contact state with a print surface of a recording medium.   The ink jet recording method according to claim 6, wherein the irradiation range of the infrared heater is removed outside the recording medium for each pass of printing scanning.   The ink jet recording method according to claim 7, wherein when the irradiation range of the infrared heater is removed to the outside of the recording medium, control for reducing the heating energy is performed.   The inkjet recording method according to any one of claims 6 to 8, wherein the upper limit of the surface temperature of the recording medium is set to a temperature 20 ° C higher than room temperature.   The inkjet recording method according to any one of claims 6 to 9, wherein a low water-absorbing recording medium is used. The inkjet recording method according to claim 10, wherein the low water-absorbing recording medium is a recording medium having a water absorption amount of 6 mL / m ² or less from the start of contact to 20 msec ^1/2 in the Bristow method.

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