JP2010194934A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of reducing ink injected wastefully, by controlling a condition pre-delivered evenly to a recording head, to a suitable pre-delivery condition in response to a delivery amount from the recording head. <P>SOLUTION: The pre-delivery amount is reduced, or an interval for pre-delivery is prolonged, in response to an increase of the delivery amount out of stored delivery amount information, based on head delivery amount information stored in the recording head. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs recording using a recording head having a plurality of ejection openings for ejecting ink. More specifically, the present invention relates to waste ink prevention such that waste ink is reduced as much as possible by controlling the preliminary discharge amount and the preliminary discharge interval based on the discharge amount information stored in the recording head.

  In an ink jet recording type recording apparatus that discharges ink droplets to form an image on a recording medium, a plurality of fine discharge ports and liquid passages communicating with them (hereinafter referred to as nozzles) are formed. The recording head used is used. In this ink jet recording apparatus, the ink in the liquid path evaporates with time, so that the ink near the meniscus surface in contact with the atmosphere at the tip of the nozzle is thickened, and there is a phenomenon that prevents ink ejection. In order to eliminate this ejection failure due to ink thickening, preliminary ejection is performed before image formation to discharge the thickened ink from the nozzles, and normal ejection is possible during image formation. However, with regard to preliminary ejection, it is not the ink that is used for the original image formation, so it is desirable to minimize wasteful ejection as much as possible. When the ejection amount of the head is large, it is possible to sufficiently discharge the thickened ink by ejecting a small number of times or by preliminary ejection with a long predetermined interval.

  Conventionally, a means for storing information on the ejection amount of the head and a means for measuring the temperature are provided, and the output γ correction table is switched between the ejection amount information and the temperature information of the head, thereby reducing graininess due to variations in the ink ejection amount and recording. There have been proposed methods for suppressing image adverse effects such as density change and bleeding (ink overflow) caused by exceeding the ink receiving capacity of the recording medium. (See Patent Document 1)

JP 2004-082625 A

  However, in the method of switching the output γ correction table from the ejection amount information and temperature information of the head proposed in the above-mentioned Japanese Patent Application Laid-Open No. 2004-082625, the graininess is reduced by aligning the gradation that varies depending on the ejection amount variation. However, it is possible to eliminate image problems such as density change and bleeding, but it is not possible to reduce wasted ink due to preliminary ejection.

  The present invention has been made paying attention to the reduction of wasted ink that cannot be solved by the above-described prior art, and controls the amount of ink required for preliminary ejection to be small when it is determined from the ejection amount information of the head that the ejection amount is large. Or, if it is determined from the discharge amount information of the head that the discharge amount is large, the minimum required amount according to the discharge amount of each head without discharging excess waste ink by controlling the preliminary discharge interval long. An object of the present invention is to provide an ink jet recording apparatus that can be controlled to a limited preliminary discharge amount.

  In order to solve the above problems, an ink jet recording apparatus of the present invention has the following configuration.

  That is, recording is performed using a recording head having an ejection port for ejecting ink, and based on the head ejection amount information stored in the recording head, the larger the ejection amount in the stored ejection amount information, the more the image It is characterized by reducing the amount of preliminary discharge used other than formation. In addition, based on the head discharge amount information stored in the recording head, the larger the discharge amount in the stored discharge amount information, the longer the interval for performing the preliminary discharge used for other than image formation. It is characterized by that.

  According to the present invention, from the discharge amount information of the recording head, it is suitable for each head by controlling to reduce the preliminary discharge amount as the discharge amount increases, or by increasing the preliminary discharge interval as the discharge amount increases. As a result, it is possible to reduce the amount of wasted ink compared to the conventional method of discharging wasted ink uniformly with respect to the discharge amount of the head. It becomes.

1 is a plan view showing an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing a recording head and a blade in an embodiment of the present invention. It is a flowchart figure which memorize | stores the discharge amount information in embodiment of this invention, and determines preliminary | backup discharge amount based on storage information. It is an image pattern diagram for determining the discharge amount rank of each nozzle row group. It is a figure which shows the relationship between the patch of each nozzle row group, a density | concentration, and a discharge amount rank. It is a figure which shows the relationship between a discharge amount rank, a preliminary discharge amount, and a preliminary discharge interval. It is a flowchart figure which memorize | stores the discharge amount information in embodiment of this invention, and determines a preliminary | backup discharge interval based on memory | storage information.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing an ink jet recording apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a recording apparatus main body provided with various mechanisms including a transport system unit (not shown) for the recording medium 12. Note that the ink jet recording apparatus in the present embodiment is a serial type ink jet recording apparatus. In this serial type recording apparatus, the recording medium 12 is intermittently conveyed in the Y direction by the conveying system unit, and the recording head 3 is moved in a direction orthogonal to the Y direction (sub-scanning direction) which is the conveying direction of the recording medium 12. The recording operation is performed while moving in a certain X direction (main scanning direction). Further, the recording apparatus main body 1 shown in FIG. 1 has a configuration in which the size in the X direction is increased so that recording can be performed on a relatively large recording medium (for example, A1 size).

  In FIG. 1, reference numeral 2 denotes a carriage. A recording head 3 and an in-tank (not shown) supplied to the recording head 3 are detachably mounted on the carriage 2. The carriage 2 reciprocates along with the recording head 3 along a direction (X direction) orthogonal to the recording medium conveyance direction. Specifically, the carriage 2 is supported so as to be movable along a guide shaft 4 disposed along the X direction, and is fixed to an endless belt 5 that moves substantially parallel to the guide shaft 4. The endless belt 5 reciprocates by the driving force of a carriage motor (CR motor), thereby reciprocating the carriage 2 in the X direction (main scanning direction).

  Further, as shown in the schematic diagram of FIG. 2, the recording head 3 includes a plurality of discharge ports 3a formed on the discharge port forming surface 3b and a plurality of liquid paths formed corresponding to the individual discharge ports 3a. (Not shown) and a common liquid chamber (not shown) for supplying ink to the plurality of liquid paths are formed. In each recording head 3 of the present embodiment, 1280 ejection ports 3a are arranged at a density of 1200 dpi (dots / inch) in the sub-scanning direction.

  Furthermore, an energy generating element that generates ejection energy for ejecting ink from the ejection port 3a is disposed in each liquid path of the recording head 3. In this embodiment, an electrothermal converter that heats the ink locally to cause film boiling and ejects the ink by the pressure is used as the energy generating element. However, the present invention is not limited to this, and an electromechanical conversion element can also be used. In the following description, the discharge port 3a and the liquid path are collectively referred to as a nozzle.

  The recording head mounted on the carriage 2 is supplied from ink tanks containing inks containing different color materials. In this embodiment, in addition to cyan, magenta, yellow, and black inks, a total of six colors of ink are stored, including light cyan and light magenta inks used to reduce the graininess of the image to be formed. The six ink tanks (not shown) are provided in the main body. Each ink tank provided in the main body is connected to an ink supply port of the corresponding recording head 3 by a tube (not shown) to supply ink to each recording head.

  Reference numeral 7 denotes a recovery processing device for keeping the ink ejection performance from each ejection port 3a of the recording head 3 in a good state. The recovery processing device 7 is held and fixed at a predetermined position of the recording apparatus main body 1. The recovery processing device 7 includes suction recovery mechanisms 7A and 7B, a lifting mechanism (not shown) that lifts and lowers them, a wiping recovery device 9, and an ink receiving box 8.

  The suction recovery mechanisms 7A and 7B perform a suction recovery process that is a form of the recovery process. Here, the suction recovery process refers to a process of replacing ink in a nozzle with ink in a state suitable for ejection by forcibly sucking ink from a plurality of nozzles formed in the recording head. Specifically, the suction recovery mechanisms 7A and 7B cover the discharge port forming surface 3b (see FIG. 2) with a cap, and generate a negative pressure in the cap by a pump (not shown) communicating with the cap. The ink is forcibly sucked from the ejection port 3a by the negative pressure. Each of the suction recovery mechanisms 7A and 7B performs a suction recovery process for each of the three nozzle row groups.

  Another form of recovery processing is preliminary ejection. This preliminary ejection is a process of keeping the ink in each nozzle of the recording head in a state suitable for ejection by ejecting ink that does not contribute to the recording operation to the ink receiving box 8. This preliminary discharge is performed mainly at the start or end of the recording operation. Further, it is performed at predetermined intervals during the recording operation.

  Further, the wiping recovery device (wiping recovery means) 9 is provided at a position that can face the end position of the moving path of the recording head 3 (for example, the home position of the recording head) in the vertical direction. The wiping recovery mechanism 9 includes a wiping mechanism (wiping means) that wipes the ejection port forming surface 3 b of the recording head using a wiping member (blade) 10, and an operating portion of the blade 10.

  Reference numeral 11 denotes an optical sensor mounted on the carriage 2. In addition to detection of the ink ejection state from the recording head 3, detection of the end and leading and trailing ends of the recording medium, and detection of the height of the recording head 3, the recording head 3. This is used to determine the discharge amount information of the ink and is composed of a photodiode and a phototransistor not shown.

  FIG. 3 is a flowchart for storing the ejection amount information of the ink jet recording head in the present embodiment and controlling the preliminary ejection amount based on the stored information. After mounting the recording head 3 on the main body at the user's site, at 101, patches of various densities predetermined for each nozzle array group as shown in FIG. 4 are printed on the recording medium, and the densities of the patches printed at 102 are printed. Is read by the optical sensor 11.

  In FIG. 103, the density of each patch in FIG. 5 is obtained from the density information read by the optical sensor 11 to obtain a linear form by the least square method, the head discharge amount rank is determined from the slope and the intercept, and the discharge amount rank is stored in the EEPROM of the head. Write information. The determination of the head discharge amount rank is not limited to the determination based on the inclination and the intercept, and can be determined based on the inclination or the intercept alone. Further, not only conversion from density data of a plurality of patches but also conversion from density data of a single patch is possible.

  In 104, it is determined whether the discharge amount rank stored in the head is equal to or greater than the threshold value or less than the threshold value, and the preliminary discharge amount is determined according to FIG. The determination of the preliminary discharge amount is not limited to the determination based on the discharge amount rank threshold value or less, and the preliminary discharge amount can be controlled to correspond to each discharge amount rank.

  FIG. 7 is a flowchart for storing the ejection amount information of the ink jet recording head in the present embodiment and controlling the preliminary ejection interval based on the stored information. After the recording head 3 is mounted on the main body at the user's destination, at 101, patches of various densities predetermined for each nozzle array group as shown in FIG. 4 are printed on the recording medium, and the density of each patch printed at 102 is printed. Is read by the optical sensor 11.

  103, the density of each patch in FIG. 5 is obtained by the least square method from the density information read by the optical sensor 11, and the head ejection amount rank is determined from the slope and the intercept, and the ejection amount rank is stored in the head EEPROM. Write information. The determination of the head discharge amount rank is not limited to the determination based on the inclination and the intercept, and can be determined based on the inclination or the intercept alone. Further, not only conversion from density data of a plurality of patches but also conversion from density data of a single patch is possible.

  In 104, it is determined whether the discharge amount rank stored in the head is greater than or less than the threshold value, and the preliminary discharge interval is determined according to FIG. The determination of the preliminary discharge interval is not limited to the determination based on the discharge amount rank threshold value or less, and the preliminary discharge interval can be controlled to correspond to each discharge amount rank.

  The storage of the discharge amount rank information to the recording head 3 is not limited to when the recording head is mounted at the user's destination, and can be stored at the time of factory inspection before shipping the head. In that case, when the user places the recording head 3 on the main body, the discharge rank information is read, and the preliminary discharge amount and the preliminary discharge interval are determined according to FIG.

  The present invention is applicable to all devices using recording media such as paper, cloth, leather, non-woven fabric, OHP paper, and metal. Specific examples of applicable equipment include office equipment such as printers, copiers, and facsimiles using an ink jet recording method, and industrial production equipment.

DESCRIPTION OF SYMBOLS 1 Recording device main body 2 Carriage 3 Recording head 3a Ejection port 3b Ejection port formation surface 4 Guide shaft 5 Endless belt 6 Encoder film 7 Recovery processing device 7A, 7B Suction recovery mechanism 8 Preliminary ejection ink receiving box 9 Wiping mechanism 10 Wiping member (blade) )
11 Optical sensor 12 Recording medium

Claims (2)

  An inkjet recording apparatus that performs recording using a recording head having an ejection port for ejecting ink, wherein the ejection amount of the stored ejection amount information is based on the head ejection amount information stored in the recording head. An ink jet recording apparatus characterized in that the larger the amount, the smaller the amount of preliminary ejection used for purposes other than image formation.   An inkjet recording apparatus that performs recording using a recording head having an ejection port for ejecting ink, wherein the ejection amount of the stored ejection amount information is based on the head ejection amount information stored in the recording head. An ink jet recording apparatus characterized in that the larger the number, the longer the interval for performing preliminary ejection used for purposes other than image formation.