JP2007276292A - Inkjet recording device and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish an excellent recording by inhibiting a recording medium from uplifting against the recording medium curling which changes depending on the changing of humidity. <P>SOLUTION: An inkjet recording device is controlled so as to change the suction pressure generated through a platen according to the humidity detected by a humidity sensor. The labor-saving and noise-reduction of the device are made possible while inhibiting uplift of the recording medium, without raising the suction pressure beyond a level needed, by controlling so as to raise the suction pressure in the environment in which the amount of curling increases. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that forms an image by ejecting ink onto a recording medium.

  The ink jet recording method is a low noise recording method for recording on a recording paper in a non-contact manner and a low running cost because ink is ejected on demand. Also, color recording can be performed relatively easily by preparing ink for recording color and discharging it from the corresponding recording head. A large format printer (hereinafter also referred to as LFP) that employs this ink jet recording method and can record an image on a relatively large size paper has been put into practical use. In particular, recording on large format paper and media has a very wide range of uses such as photo, POP, signature, art, and CAD (Computer Aided Design). For this reason, the LFP needs to be compatible with media of various types and materials according to the application.

  Among various media, there is a media in which the media is curled by being influenced by the use environment of the printer and the environment in which the media before use is stored. In particular, it has been found that media base materials and coating layer materials suitable for inkjet are susceptible to humidity.

  As a conventional inkjet printer, a printer provided with a temperature sensor is widely known in order to cope with environmental changes. In addition, a configuration of an ink jet printer provided with a sensor so as to detect humidity in addition to temperature is also known (for example, Patent Document 1).

The invention described in Patent Document 1 discloses a configuration of an ink jet printer that performs recording by melting solid ink and ejecting liquid ink, and is transported to a recording medium deformed by heat or humidity. A configuration for adjusting the amount is disclosed.
Japanese Patent Laid-Open No. 10-230588

  The present invention pays attention to the above-mentioned problems caused by changes in humidity, particularly in the environment. In particular, as an ink jet medium, a receiving layer (hereinafter also referred to as a coat layer) is often formed on the surface on which recording is performed in order to receive ink. In some cases, the material of the receiving layer is affected by humidity change, and the medium itself curls.

  For example, when a resin-coated (RC) paper having a low water absorption of a substrate or a film-type recording medium is placed under a low humidity, the moisture in the receiving layer having a high water absorption evaporates. Due to the evaporation of the water, the side on which the medium receiving layer is provided shrinks. On the other hand, the base material hardly shrinks. Therefore, the medium curls in a state where the receiving layer side, that is, the surface to be printed is inside. When such curling occurs before printing, the end position of the leading edge of the roll paper is in a state of being lifted by curling as shown in FIG. An arrow 51 in FIG. 5 indicates a direction of relative movement between the recording head 52 and the recording medium 103 when the recording medium 103 is conveyed. In the figure, an arrow 52 indicates the direction in which the edge of the paper is lifted by curling. As a result of the occurrence of curling as described above, when the medium is transported to a position where the ink jet recording head is scanned, the recording head rubs the surface of the medium, which may cause the medium surface to become unnecessarily dirty.

  In addition, a recording medium having high rigidity and high water absorption, such as thick mat-coated paper and art paper, has a higher rigidity because the moisture of the recording paper itself evaporates under low humidity. In general, large-sized paper is often supplied in the form of roll paper, and in this case, the paper is unwound and conveyed to a printing position. Since it is stored in a rolled state until it is printed, there are wrinkles in the wound state on the medium. The platen 104 is a member that supports the transported recording medium at a recording position by the recording head. When recording, a recording medium exists between the recording head and the platen. In the configuration in which the suction mechanism 91 is provided on the platen, as shown in FIG. 9, even if the media is wrinkled so that the central portion is lifted, the media can be kept flat. In FIG. 9, the same reference numerals as those in FIG. The recording medium 103 is conveyed from the right side to the left side in the drawing. In FIG. 9, the configuration of the roll-shaped recording medium is omitted without being shown. After the recording medium 103 passes between the rollers 105 and 106, curling occurs due to the rigidity of the recording medium. This curl is generated when the state wound on the roll paper becomes a wrinkle.

  As described above, when the rigidity is increased by the evaporation of moisture, it is difficult to keep the medium flat at the printing position even if the curl generated in the state where the medium is wound is sucked by the platen 104. When the recording head is scanned in a state where such curling has occurred, the recording head may rub against the surface of the medium, which may cause the surface of the medium to become unnecessarily dirty.

  Note that the problem caused by the curling of the medium is not limited to the above-described contamination of the surface of the recording medium, and there is also a conveyance failure caused by the recording head colliding with the recording medium.

  An object of the present invention is to maintain the flatness of a recording sheet against curling caused by humidity as described above, and to prevent the problem of contamination on the surface of a recording medium and poor conveyance.

  The present invention has been made to solve the above-described problems, and uses a recording head in which a plurality of ejection openings for ejecting ink are arranged, and the recording head and the recording medium are moved relative to each other to thereby perform the recording. An ink jet recording apparatus that performs recording by discharging ink from a head onto a recording surface of a recording medium, the transporting platen supporting a recording medium transported at a recording position by the recording head, and the transporting platen Based on the detection result of the humidity detection means, the suction means for sucking the recording medium transported above to the transport platen side, the humidity detection means for detecting the humidity of the environment of the recording apparatus, and the suction means And a control means for controlling the suction force by.

  Also, using a recording head in which a plurality of ejection openings for ejecting ink are arranged, the recording head and the recording medium are relatively moved, and ink is ejected from the recording head to the recording surface of the recording medium. A method for controlling an inkjet recording apparatus that performs recording, a humidity detection step for detecting the humidity of the environment of the recording apparatus, and a recording that is generated on a transport platen that supports a recording medium to be transported according to the detected humidity And a step of controlling a suction force for sucking the medium onto the transport platen.

  According to the present invention, it is possible to prevent a conveyance failure caused by curling of a recording medium caused by humidity and a problem of contamination of the recording medium caused by the recording head rubbing the surface of the recording medium. According to the present invention, it is possible to prevent a conveyance failure in a low humidity environment and the surface of the recording medium from becoming dirty. Further, according to the configuration of the present invention, it is possible to strongly set the suction force of the platen only under a specific environment, so that it is possible to save the apparatus. Furthermore, by performing control to increase the suction force only when it is necessary to increase the suction force of the platen, it is possible to reduce noise generated by suction during normal use.

  FIG. 1 is a schematic diagram of a color ink jet recording apparatus to which the present invention can be applied. In the figure, reference numeral 101 denotes a carriage on which the ink jet recording head 102 is mounted. In this embodiment, the recording head is provided with a plurality of ejection openings so that a plurality of color inks and black ink can be ejected. Note that the ejection port is provided with a recording element for performing recording by ejecting ink.

  The apparatus is provided with a plate-like platen 104 for receiving the recording paper 103, and the platen 104 is provided with a plurality of fine suction ports (not shown). The recording paper 103 can be brought into close contact with the platen 104 by sucking air from the suction port. The suction means in the configuration of the present invention is configured by general means such as a pump for generating a force for sucking air, a suction path for generating pressure by the pump to the fine holes of the platen 104, and the like. The

  Further, a paper discharge roller 105 for paper feeding and an auxiliary roller 106 that follows the paper discharge roller and feeds the paper while pressing the recording paper 103 are provided in the apparatus. The recording paper 103 is conveyed on the platen 104 while being gradually sent out by the paper discharge roller 105 and the auxiliary roller 106.

  FIG. 2 is a block diagram showing the configuration of the control system of the ink jet printer shown in FIG. Reference numeral 201 denotes an interface for inputting image data from an external personal computer or the like. Further, the printer has a temperature sensor 202 as a means for detecting the temperature in the usage environment of the inkjet printer 1 and a humidity sensor 203 as a means for detecting humidity. The control unit 300 includes a CPU 301, a ROM 302, and a RAM 303. The control unit 300 controls the ink jet recording head 209, the head carriage 210, and the paper transport unit 211 based on the above-described interface 201, temperature sensor 202, humidity sensor 203, and various signals and data input from the operation panel 204. Control.

Example 1
Next, an example of control according to the present invention will be described with reference to FIG. First, in step S1, the recording paper 103 is set, and the setting process to the conveyance unit 211 is performed. Next, in step S2, recording data is generated by a personal computer, and in step S3, recording paper (glossy paper, plain paper, matte paper, art paper, synthetic paper, cloth, etc.) that is actually recorded is recorded. The printing speed or the number of printing passes is selected. By executing steps S2 and S3, the result selected together with the image signal from the personal computer is transmitted to the control unit of the printer. Furthermore, in accordance with the input value of the humidity sensor at this time, the required suction pressure of the paper transport unit 211 is calculated in the print mode table in step S4. The control unit 204 controls the paper transport unit 211 according to the suction pressure.

  FIG. 4 shows the temperature and humidity environment in which this apparatus is used. For example, when using in the range of temperature 10-30 degreeC and humidity 10-80%, it divides into the low humidity environment A and the high humidity environment B. In this embodiment, the humidity of less than 40% is classified as a low humidity environment A, and the humidity of 40% or more is classified as a high humidity environment B. Then, the set value of the suction pressure in the following embodiment may be changed in the environmental classification.

  In particular, in this embodiment, as shown in FIG. 5, for a medium having a large curling surface side curl with respect to the humidity of the recording paper 103, such as RC (resin coat) -based glossy / semi-glossy paper, synthetic paper, film, etc. The suction pressure is increased under low humidity. When these recording media are dried under low humidity, the curling to the print surface side is large, the ends of the recording media are lifted with respect to the platen 104, and the recording head 101 and the carriage 102 are easily rubbed. . FIG. 6 is a graph showing characteristics of humidity and print surface side curl for various media. FIG. 6 shows the curl characteristics of synthetic paper, clear film, and glossy paper as an example. It can be understood from FIG. 6 that the curl amount on the printing surface greatly depends on the humidity of each medium.

  FIG. 10 is a table showing, as a comparative example, the case where the suction pressure is not changed with respect to the quality of the conveyance state when the suction pressure is increased. In the table shown in FIG. 10, “x” indicates that the carriage rubs the media surface, and “◯” does not occur. In this way, the curling problem occurring in the low humidity environment A can be suppressed by strongly shifting the suction pressure, and the curling on the printing surface side of the recording medium 103 can be suppressed, and the carriage rubs the printing surface of the printing medium 103. Print can be achieved without.

  In the example of FIG. 10, since the occurrence of curl varies depending on the type of media, in order to perform more appropriate control, the suction pressure during conveyance is controlled based on the type of media and the detected humidity. It is preferable to do.

  In step S3 of FIG. 3, the control may be made different in light of the table section shown in FIG. 4 with reference to the temperature detected by the temperature sensor. In the table of FIG. 4, control is performed in a temperature range of 10 to 30 degrees Celsius. If the detected temperature is outside the temperature range to be controlled, the suction pressure may be further increased when the humidity is low, or the printing operation may be stopped outside the control target.

(Example 2)
Next, a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 7 shows the relationship between stiffness and humidity with respect to a medium having a large curl (roll curl curl) caused by roll paper curl. The definition of “winding curl” here is the curl amount of the recording medium 103 with respect to the winding direction of the paper sheet 501 as shown in FIG. This curl amount is shown in FIG. 8 as an amount (arrow 80) curled in the “−” (minus) direction in the figure when the medium is pulled out horizontally from the roll paper. This medium with a large curl curl becomes more rigid when the humidity is lowered, and is difficult to suck into the platen.

  FIG. 11 is a table showing the quality of the conveyance state when the suction pressure is increased as an example. In the table, the case where the suction pressure is not changed is shown as a comparative example. In FIG. 11, “×” indicates a case where the carriage rubs the surface of the medium, and “◯” indicates a case where no occurrence occurs. In this way, in the low humidity environment A, it is possible to prevent the recording medium 103 from floating on the platen by increasing the suction pressure, and print well without rubbing the surface of the medium when the carriage is scanned. I was able to.

  In the second embodiment, as in the first embodiment, the occurrence of curl differs depending on the type of media. Therefore, in order to perform more appropriate control, the amount of curling is determined based on the type of medium and the detected humidity. It is preferable to control the suction pressure.

(Example 3)
Next, a third embodiment of the present invention will be described with reference to the drawings.

  In the third embodiment, the suction pressure may be increased in consideration of both the curl and curl toward the printing surface and the stiffness. (Table 3) For example, the suction pressure is applied to a medium having a curl amount of 20 mm (10 ° C./10%) or more on the printing surface side, a media stiffness of 1000 mgf (10 ° C./10%), and a curl curl curl of −60 mm or more. It may be increased.

  FIG. 12 is a table showing the quality of the conveyance state for each medium when the suction pressure is changed in each of the low humidity environment A and the high humidity environment B. The table also shows the conveyance state when the suction pressure is not changed as a comparative example. In the table, “x” indicates a case where the recording head rubs the media surface due to curling, and “◯” indicates a case where printing can be performed without the recording head rubbing the media surface. As shown in FIG. 12, in the low-humidity environment A, by increasing the suction pressure, curling on the platen can be suppressed, and printing can be achieved without rubbing the surface of the recording medium 103 by the recording head. Can do.

  Also in the third embodiment, since the occurrence of curl differs depending on the type of media as in the above-described embodiment, in order to perform more appropriate control, the conveyance time is determined based on the type of medium and the detected humidity. It is preferable to control the suction pressure.

(Other examples)
The table shown in FIG. 4 shows an example in which the suction pressure of the platen is made different in two environments of a low humidity environment and a high humidity environment, but the present invention is not limited to this configuration. For example, the detected humidity may be classified into 3 or more, and the suction pressure may be changed for each classified humidity range.

It is a figure explaining an example of an inkjet recording device structure which can apply the present invention. It is a figure explaining the inkjet recording device control part which can apply this invention. It is a figure which shows an example of the control sequence which can apply this invention. It is a figure which shows the temperature and humidity range which can apply this invention. It is a figure explaining the definition of the curl on the printing surface side. It is a figure which shows the relationship between the printing surface side curl of recording media, and humidity. It is a figure which shows the relationship between the rigidity and humidity with respect to a medium with a large curl curl of a recording medium. The figure which shows the definition of a curl curl amount. It is a figure which shows the relationship between a curl curl and carriage rubbing. It is a table | surface which shows the quality of the conveyance state in Example 1 of this invention. It is a table | surface which shows the quality of the conveyance state in Example 2 of this invention. It is a table | surface which shows the quality of the conveyance state in Example 1 of this invention.

Explanation of symbols

102 Inkjet recording head 103 Recording paper 104 Platen 202 Temperature sensor 203 Humidity sensor 204 Control unit

Claims (4)

Using a recording head in which a plurality of ejection openings for discharging ink are arranged, the recording head and the recording medium are moved relative to each other, and ink is ejected from the recording head onto the recording surface of the recording medium. An inkjet recording apparatus that performs
A transport platen for supporting a transported recording medium at a recording position by the recording head;
A suction means for sucking a recording medium transported on the transporting platen toward the transporting platen;
Humidity detecting means for detecting the humidity of the environment of the recording device;
Control means for controlling the suction force by the suction means based on the detection result of the humidity detection means;
An ink jet recording apparatus comprising:   2. The ink jet recording apparatus according to claim 1, wherein the control unit performs control to increase the suction force when the detected humidity is relatively low than when the humidity is relatively high.   3. The ink jet recording apparatus according to claim 1, wherein the control of the air suction force based on the result of detecting the humidity is varied according to the type of recording medium on which recording is performed. Using a recording head in which a plurality of ejection openings for discharging ink are arranged, the recording head and the recording medium are moved relative to each other, and ink is ejected from the recording head to the recording surface of the recording medium. A method for controlling an inkjet recording apparatus, comprising:
A humidity detection process for detecting the humidity of the environment of the recording device;
A step of controlling a suction force for sucking the recording medium to the transporting platen, which is generated on the transporting platen that supports the transported recording medium according to the detected humidity;
An ink jet recording apparatus comprising:

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