JP2009137120A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that ink drying time is not decided just until the leading edge of a printing medium under printing comes into contact with a printing medium printed precedently in conventional ink drying waiting control, consequently, printing operation suspension control for head protection is started before a printing head attains predetermined conveying amount, and then efficient head protection is not performed. <P>SOLUTION: In the inkjet printer, whether or not head temperature detected by a head temperature detection means exceeds predetermined temperature is decided before conveying the printing medium. When it exceeds the predetermined temperature, the ink drying time is decided by an ink drying time deciding means even when a printing medium conveying amount deciding means decides that the conveying amount of the printing medium does not exceed the predetermined one. A control means which suspends conveyance of the printing medium under printing until the ink drying time elapses when deciding that the ink drying time does not elapse as a result is provided to the inkjet printer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet printing apparatus, and more particularly to an ink jet printing apparatus characterized in that print medium holding control by ink drying is performed while referring to a head temperature.

  Conventionally, the time required for ink drying elapses in order to prevent the print medium that has been printed in advance from coming into contact with the subsequent print medium and rubbing the ink on the previous print medium to cause deterioration of the image. There has been an inkjet printing apparatus that suspends a printing operation up to. For example, the control method sets a drying time for ink fixing according to the ink density, and stores the position on the recording medium printed at a high density. Then, it is determined whether or not the drying time has elapsed when the leading edge of the print medium of the next page reaches a predetermined conveyance amount immediately before contacting the high-density print position of the preceding print medium. As a result of the determination, if the drying time has not elapsed, the printing operation is suspended until the time elapses.

Conventionally, in order to protect the recording head, the head temperature is monitored, and when the head temperature exceeds a predetermined temperature, the printing operation is suspended and the head temperature is lowered (hereinafter, head protection control). There has been an inkjet printing apparatus that performs the above.
JP-A-7-205416 JP-A-6-336024

  In the conventional ink waiting control, the ink drying time is not determined until immediately before the leading edge of the printing medium being printed comes into contact with the previously printed printing medium. For this reason, head protection control may be entered before the print medium reaches a predetermined transport amount, and efficient head protection control has not been performed.

  In the present invention, the head temperature is determined before transporting the print medium, and if the predetermined temperature just before the head protection control is reached, the ink drying time is determined regardless of the total transport amount of the print medium. Do. As a result, when the ink drying time has not elapsed, it is possible to efficiently suppress the temperature rise of the head by previously deferring the conveyance of the print medium.

  In order to solve the above-described problem, the ink jet printing apparatus according to the present invention determines whether or not the head temperature detected by the head temperature detecting means exceeds a predetermined temperature before transporting the print medium. When it is determined that the temperature exceeds the predetermined temperature, the ink drying time determination unit performs determination even when the print medium conveyance amount determination unit determines that the predetermined conveyance amount is not exceeded. As a result, when it is determined that the ink drying time has not elapsed, it has a control means for holding the conveyance of the printing medium being printed until the time has elapsed.

  In the present invention, the head temperature is determined before transporting the print medium, and if the predetermined temperature just before the head protection control is reached, the ink drying time is determined regardless of the total transport amount of the print medium. Do. As a result, when the ink drying time has not elapsed, it is possible to efficiently suppress the temperature rise of the head by previously deferring the conveyance of the print medium. By doing so, it is possible to optimally protect the recording head and improve durability.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view schematically showing an inkjet printing apparatus to which the present invention can be applied. The print medium 105 inserted into the paper feed position of the printing apparatus 100 is fed in the direction of arrow P by the feed roller 106 and conveyed to the printable area of the recording head 104. A platen 107 is provided below the print medium 105 in the printable area. The carriage 101 is movable in the direction along the axial direction by two guide shafts 102 and 103, and the scanning region including the printing region is the main scanning direction by driving a stepping motor (not shown). Reciprocal scanning is performed along the directions indicated by arrows Q1 and Q2. When one main scan is completed, the print medium is conveyed by a fixed amount in the sub-scanning direction, which is the direction of arrow P, to prepare for the next main scan. These main scanning and sub-scanning are repeated to perform printing operation for one page.

  In FIG. 1, a recording head 104 mounted on a carriage 101 includes an ejection port capable of ejecting ink and an ink tank that accommodates ink, and the ejection port of the recording head applies ink to a print medium positioned below. It is mounted on the carriage so as to discharge and print. Reference numeral 108 denotes a switch unit and a display unit. The switch unit is used to turn on / off the printing apparatus and set various printing modes. The display unit is configured to display the state of the printing apparatus. Yes.

  The configuration of the recording head is capable of printing four colors Y, M, C, and Bk, the number of Y, M, and C ejection openings is 128 each, and the number of Bk is 320, and the arrangement of ejection openings for each color The pitch is 1/600 dpi and about 42 microns with respect to several sub-scanning directions. The drive frequency of the recording head is 15 kHz, and a printing operation is possible at a density of 600 dpi in the main scanning direction. Therefore, the main scanning speed of the carriage during the printing operation is 25 inches / s.

  In the present embodiment, a heating element that generates thermal energy is provided in the vicinity of each ejection port of the recording head in order to eject ink droplets. The ink in the nozzle heated rapidly by the heat generated by the heating element forms bubbles by film boiling, and ink droplets are ejected toward the print medium by the pressure of bubble generation to form characters and images. Further, a head temperature sensor is provided on the same substrate as the heating element, and the head temperature can be detected. A recording method using a heating element, which is an electrical / thermal converter, is called a so-called bubble jet (registered trademark) recording method because it uses bubbles formed by applying thermal energy when ink droplets are ejected.

  In the present invention, the recording head is not limited to this type, and for example, an ejection type recording head using a piezoelectric element may be used.

  FIG. 2 is a block diagram showing a main part of an ink jet printing apparatus to which the present invention can be applied. Character or image data to be printed is transmitted from the host apparatus 500 to the printing apparatus 100 and stored in the reception buffer 401. Further, data for confirming whether the data is correctly transferred and data for informing the operation state of the printing apparatus 100 are transmitted from the printing apparatus 100 to the host apparatus 500.

  Data stored in the reception buffer 401 is processed into data for performing printing when the recording head performs main scanning under the control of the CPU 402, and is stored in the print buffer unit in the random access memory unit 403. . The data of the print buffer unit is transferred to the recording head 104 by the recording head control unit 410, and the recording head is controlled to print character and image data. The random access memory unit 403 also holds information such as ink drying time. The recording head control unit 410 detects temperature information or the like indicating the state of the recording head 104 and sends it to the CPU 402, transmits the information to the recording head control unit 410, and controls the recording head.

  A machine control unit 404 drives and controls a machine unit 405 such as a carriage motor or a line feed motor in response to a command from the CPU 402.

  The sensor / SW control unit 406 sends a signal from the sensor / SW unit 407 including various sensors and SW (switch) to the CPU 402.

  The display element control unit 408 is configured to control the display unit 409 composed of LEDs, liquid crystal display elements, and the like of the display panel group according to a command from the CPU 402.

  FIG. 3 is a flowchart showing control of waiting for ink drying in the ink jet printing apparatus according to the present invention. A program for realizing this processing is stored in the ROM 411 in FIG. 2, and the CPU 402 executes the program. In this embodiment, printing is performed based on a print command and data transferred by the host computer to the reception buffer 401 in FIG. The print command includes a print medium conveyance command. The predetermined temperature described in step S304 of this flowchart is a temperature lower than the temperature at which the above-described head protection control is necessary. If printing is continued at a temperature close to that, the head protection control is performed. The temperature that is expected to enter. It is assumed that the head protection control execution determination is performed separately from the control in this flowchart. Normally, a periodic timer is used to periodically detect the head temperature and make a determination.

  Based on the above, a description of the flowchart is given below.

  First, in step S301, it is determined whether or not it is a print medium conveyance command. If it is not a print medium conveyance command, the process proceeds to step S302, and control according to the received command is performed. When a print medium command is received, the head temperature is acquired (step S303), and it is determined whether the head temperature exceeds a predetermined temperature (step S304). If the temperature is lower than the predetermined temperature, the process proceeds to step S305 to determine the conveyance amount. It is determined whether or not the total transport amount of the print medium exceeds the predetermined transport amount for which the ink drying time determination should be performed in the current transport. If it is determined that it exceeds, the process proceeds to step S306 to enter the ink drying waiting determination. If it does not exceed, the process proceeds to print medium conveyance processing in step S309. If the head temperature exceeds the predetermined temperature in step S304, it is immediately determined whether it is necessary to wait for ink drying in step S306 regardless of the transport amount of the print medium. As a result, if it is determined that it is necessary, in step S308, the conveyance of the print medium is suspended until the time necessary for ink drying has elapsed. If it is determined in step S307 that it is not necessary to wait for ink to dry, or if the print medium holding process is completed in step S308, the print medium is conveyed (step S310).

  Finally, in step S310, it is determined whether or not printing is finished. If printing is finished, the printing medium is discharged in step S311 and printing is finished. If printing has not ended, the process returns to step S301.

1 is a perspective view illustrating an outline of a recording unit of an ink jet printing apparatus according to an embodiment of the present invention. It is a block diagram which shows schematic structure of the inkjet printing apparatus which concerns on this Embodiment. 4 is a flowchart showing control of waiting for ink drying in the ink jet printing apparatus according to the embodiment of the present invention.

Explanation of symbols

100 Printing device 101 Carriage 102 Guide shaft a
103 Guide shaft b
DESCRIPTION OF SYMBOLS 104 Recording head 105 Recording medium 106 Feed roller 107 Platen 108 Switch part and display part 401 Reception buffer 402 CPU
403 Random Access Memory Unit 404 Machine Control Unit 405 Machine Unit 406 Sensor / SW Control Unit 407 Sensor / SW Unit 408 Display Element Control Unit 409 Display Element Unit 410 Recording Head Control Unit 500 Host Device

Claims (1)

In an inkjet printing apparatus that performs printing by ejecting ink while moving a recording head in the main scanning direction and transporting a print medium in the sub-scanning direction,
Detecting means for detecting the temperature of the recording head;
Storage means for storing the time required to dry the ink ejected by the recording head;
A transport amount determination means for determining whether or not the total transport amount of the print medium being printed by the transport exceeds a predetermined transport amount before transporting the print medium;
Whether the ink drying time has elapsed with reference to the ink drying time of the preceding print medium stored in the storage means when it is determined by the transport amount determining means that the predetermined transport amount is exceeded. A drying time determining means for determining;
If it is determined by the drying time determination means that the drying time has not elapsed, a holding means for holding the conveyance of the print medium until the time has elapsed,
It is determined whether or not the head temperature detected by the detection unit exceeds a predetermined temperature before transporting the print medium. If the head temperature exceeds the predetermined temperature, the predetermined transport amount is set by the transport amount determination unit. Even when it is determined that the time does not exceed, the determination is made by the drying time determination means, and when it is determined that the drying time has not elapsed, the conveyance of the printing medium being printed is suspended until the time has elapsed. An ink jet printing apparatus.

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