JP2013078881A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in an inkjet recording apparatus having a cap for integrating and sealing a plurality of colors, wherein dye concentration in the head might change after the leaving, and then, image unevenness occurs by concentration distribution in the nozzle row if the multipath recording is carried out by the mask in which the duty of the nozzle center part is high, and the duty of the nozzle end is low.SOLUTION: When the predetermined time from the last auxiliary discharge has passed during printing, the auxiliary discharge is executed after the recording of the scanning has completed. On this occasion, the auxiliary discharge is executed in the number of departures, few at the nozzle center part, and a lot at the nozzle ends.

Description

  The present invention relates to an ink jet recording apparatus and a discharge recovery method of the ink jet recording apparatus.

  In recent years, OA devices such as relatively inexpensive personal computers and word processors have become widespread, and various recording devices for printing out information input by these devices, speed-up technology for the devices, and technology for improving image quality have rapidly increased. It has been developed.

  Among the recording apparatuses, a serial printer using an ink jet recording method has attracted attention as a recording apparatus that realizes high-speed or high-quality printing at low cost.

  For such a printer, a technique for performing high-speed printing includes, for example, a bidirectional printing method, and a technique for performing high-quality printing includes, for example, multipass.

  As a technique for achieving both high-speed multi-pass printing and high image quality, for example, as shown in Patent Document 1 and Patent Document 2, a technique for distributing the mask duty in the nozzle row direction is known.

  In an ink jet recording apparatus, a configuration in which a nozzle portion is sealed with a cap is generally used to prevent drying of the nozzle tip during non-printing. From the viewpoint of cost and the like, as a cap configuration, for example, as shown in Patent Document 3, for example, a configuration that employs a configuration in which the nozzles of a plurality of colors are sealed with a single cap is widely known.

  In this configuration, the following problems may occur if there is a difference in the amount of water in each color ink sealed with one cap.

  At the time of sealing the cap, although the water vapor pressure in the cap is kept constant, moisture is always exchanged between the inks. That is, among a plurality of inks, ink having a relatively large amount of water releases moisture into the cap, and ink having a relatively small amount of water absorbs moisture in the cap. For this reason, when the cap is left for a long period of time, the dye concentration in the vicinity of the ink nozzle having a high water content increases, and the dye concentration in the vicinity of the ink nozzle having a low water content decreases. When printing is started in this state, recording is performed with an ink density different from the original ink density, and therefore, recording is performed with a density different from the intended density. By ejecting ink, normal density ink is gradually supplied from the flow path to the vicinity of the nozzles, so that density abnormalities are eliminated by performing recording.

  At this time, if ink is ejected evenly at any nozzle position during recording, there is a problem that the density of the recorded image differs from the intended density, but unevenness does not occur, and the degradation of the recording quality is slight. However, as described above, when printing is performed with a mask distributed in the nozzle row direction, the usage ratio of the nozzle center and the nozzle end is different, so the degree of density abnormality cancellation depends on the nozzle position. Different. For this reason, for example, the density of the ink ejected at the nozzle end portion and the ink ejected at the nozzle center portion are different, causing unevenness in the image and greatly reducing the recording quality.

  This phenomenon will be described with reference to FIGS. FIG. 1 schematically shows multi-pass printing (three passes in this example) in which all nozzles are used evenly, and FIG. 2 shows multi-pass in which the frequency of use varies in the direction of the nozzle array using an uneven mask. It is a schematic representation of the record. FIGS. 1B and 2B schematically show how the density is distributed at each nozzle position in each pass when the ink density is normal. FIGS. 1 (c) and 2 (c) schematically show how the density is distributed at each nozzle position in each pass when a density abnormality occurs (in this example, an example of darkening). It is a representation. In FIG. 1 (c), the nozzles are uniformly darkened at any nozzle position as compared with FIG. In this case, the recording density is high overall, but it is uniform and no unevenness occurs. FIG. 2C shows how the density is distributed at each nozzle position in each pass when the use frequency is different. At this time, since the density abnormality is quickly eliminated at the place where the usage frequency is high, the difference in density from the normal time is small, and since the density abnormality is not easily solved at the place where the usage frequency is low, the density difference from the normal time is large. At this time, the recording density is not only thickened as a whole, but also a relatively dark part and a relatively thin part are generated and recognized as unevenness.

  As a countermeasure against this problem, suction recovery is performed before recording, and ink that is not in the desired density existing near the nozzle is forcibly discharged, or preliminary ejection is performed during recording, and the ink is present near the nozzle. It is conceivable to perform recording while discharging ink that does not have a desired density. Patent Document 4 discloses a method of counting the number of times of ejection during printing for each nozzle and determining the number of preliminary ejections according to the number of times.

JP2009-061773 JP 2002-96455 A JP 2001-063102 A Japanese Patent Laid-Open No. 05-338134

  However, in a system that performs suction recovery before recording, a new problem arises in that the amount of ink consumed by suction becomes enormous and the amount of ink that can be used for recording is greatly reduced.

  Moreover, the following problems exist in the method of Patent Document 3.

  In recent inkjet recording apparatuses, a large number of nozzles has been implemented in order to achieve high speed. When the method of Patent Document 3 is applied when the number of nozzles is large, it is necessary to hold the result of counting the number of ejections during printing for each nozzle, and thus a huge amount of memory is required. For this reason, it leads to the cost increase of an inkjet recording device.

  The ink jet recording apparatus of the present invention for solving the above-described problems is as follows.

  An ink jet recording apparatus that performs preliminary ejection at a duty different from a mask duty in a mode in which printing is performed using a mask having a duty distribution in the nozzle row direction.

  In a mode where printing is performed using a mask whose mask duty distribution is low at the nozzle end and high at the nozzle center, the pre-discharge duty during recording is high at the nozzle end and at the nozzle center. Is an ink jet recording apparatus having a low duty.

  In a mode that uses a mask with a duty distribution in the nozzle row direction, the mask duty is regarded as the frequency of use in the nozzle row direction in printing, and preliminary ejection is performed with a duty distribution different from the mask duty, thereby suppressing ink waste and cost increase. However, unevenness can be reduced.

It is a figure explaining image formation when the usage frequency of each nozzle is equal. It is a figure explaining image formation when the usage frequency of each nozzle differs. 1 is a block diagram conceptually showing an overall configuration of an ink jet recording system of an embodiment. 1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a perspective view which shows the detail of the head cartridge 1000 used in embodiment of this invention. It is sectional drawing which shows the internal structure of the inkjet head of a present Example. It is a schematic diagram which shows a mode when sealing to a head by capping. It is a figure explaining the interface screen of the control apparatus of a present Example. It is a figure explaining the mask duty of each scan at the time of recording of this example (part 1). It is a figure explaining the mask duty of each scan at the time of recording of this example (part 2). It is a figure explaining the mask duty of each scan at the time of recording of this example (part 3). It is a figure explaining the mask duty of each scan at the time of recording of this example (part 4). It is a figure which shows the flow of the recording mode determination in the recording device of a present Example. It is a figure which shows the processing flow of the recording operation of a present Example. It is a figure which shows the number of preliminary discharges in the recording operation of a present Example (the 1). It is a figure which shows the number of preliminary discharges in the recording operation of a present Example (the 2). It is a figure which shows the processing flow of the recording operation of a present Example. It is a schematic diagram of the ink flow in the liquid chamber.

[Example 1]
Specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a diagram illustrating a control configuration of a recording system including the recording apparatus 200 and the information processing apparatus (host computer) 100 according to the present embodiment. Reference numeral 200 denotes an ink jet recording apparatus that performs recording by discharging ink from a recording head. Reference numeral 100 denotes an information processing apparatus that serves to supply image data to the ink jet recording apparatus 200 and to control the ink jet recording apparatus 200. The recording apparatus 200 and the information processing apparatus 100 are connected by a known communication means (interface) and can communicate with each other. The information processing apparatus 100 generates image data to be supplied to the recording apparatus 200 based on a user instruction, or causes the recording apparatus 200 to perform a recording operation based on the image data. In the information processing apparatus 100, one recording mode can be selectively designated from among a plurality of recording modes that can be executed by the recording apparatus 200. In this embodiment, as will be described later, one recording mode is selectively designated from among a plurality of recording modes by a combination of “type of recording medium” and “recording quality” designated by the user. In this way, information regarding the recording mode specified in the information processing apparatus 100 is transmitted to the recording apparatus 200. In the recording apparatus 200, a recording mode to be executed is set based on the transmitted information.

  The recording apparatus 200 is provided with a controller 213, a recording head 21, a head drive circuit 202, a carriage 2, a carriage motor 204, a conveyance roller 14, a conveyance motor 206 and the like. The head driving circuit 202 is a circuit for driving the recording head 21, and the recording head 21 is driven by the head driving circuit 202 to eject ink. The carriage motor 204 is a motor for reciprocating the carriage 2 for mounting the recording head 21. The transport motor 206 is a motor for transporting the transport roller 14 for transporting the recording medium. A controller 213 for controlling the entire apparatus is provided with a CPU 210 in the form of a microprocessor, a ROM 211 storing a control program, a RAM 212 used when the CPU processes image data, and the like. The ROM 211 stores a plurality of types of mask patterns corresponding to each printing mode, a control program for controlling multi-pass printing, and the like. The controller 213 sets a recording mode to be executed based on the information regarding the recording mode transmitted from the information processing apparatus 100. Further, the controller 213 controls the head drive circuit 202, the carriage motor 204, and the transport motor 206 in order to execute multi-pass printing, and generates image data corresponding to each scan of multi-pass printing. Specifically, the controller 213 generates image data corresponding to each scan by dividing image data corresponding to the same image area (predetermined area) using the mask pattern read from the ROM 211 in accordance with the control program. Further, the controller 200 controls the head driving circuit 202 so that ink is ejected from the recording head 21 in accordance with the divided image data.

  FIG. 4 is a perspective view for explaining the internal structure of the ink jet recording apparatus applicable to the present invention. In the figure, reference numeral 1000 denotes a replaceable head cartridge, which includes a recording head 21 for ejecting ink and an ink tank for supplying ink to the recording head 21. Reference numeral 2 denotes a carriage that detachably holds the head cartridge 1000. Reference numeral 3 denotes a holder for fixing the head cartridge 1000 to the carriage 2. When the cartridge fixing lever 4 is operated after the head cartridge 1000 is mounted in the carriage 2 by the holder 3, the head cartridge 1000 is pressed against the carriage 2 in conjunction therewith. The head cartridge 1000 is positioned by the pressure contact, and at the same time, a contact between a required signal transmission electrical contact provided on the carriage 2 and an electrical contact on the head cartridge 1000 side is made. Reference numeral 5 denotes a flexible cable for transmitting an electric signal to the carriage 2. Reference numeral 6 denotes a pulley interlocked with a carriage motor that serves as a driving source for reciprocating the carriage 2 in the main scanning direction, and reference numeral 7 denotes a carriage belt that transmits the driving force to the carriage 2. Reference numeral 8 denotes a guide shaft that extends in the main scanning direction to support the carriage 2 and guide its movement. Reference numeral 9 denotes a transmissive photocoupler attached to the carriage 2, and reference numeral 10 denotes a light shielding plate provided near the home position. When the carriage 2 reaches the home position, the light shielding plate 10 blocks the optical axis of the photocoupler 9, and it is detected that the carriage 2 is at the home position. Reference numeral 12 denotes a home position unit including a recovery system such as a cap member that caps the front face of the recording head, a suction means that sucks the inside of the cap, and a member that wipes the front face of the head.

  Reference numeral 13 denotes a discharge roller for discharging the recording medium, which sandwiches the recording medium in cooperation with a spur roller (not shown) and discharges it outside the recording apparatus. A conveyance roller 14 conveys the recording medium by a predetermined amount in the sub-scanning direction.

  FIG. 5 is a perspective view for explaining details of the head cartridge 1000. In FIG. 5, 15 is a replaceable ink tank for storing Bk (black) ink, and 16 is a replaceable ink tank for storing inks of C (cyan), M (magenta), and Y (yellow) colorants. is there. Reference numeral 17 denotes an ink supply port of the ink tank 16 which is connected to the head cartridge 1000 and supplies ink, and 18 denotes an ink supply port of the ink tank 15 similarly. The ink supply ports 17 and 18 are connected to the supply pipe 20 and configured to supply ink to the recording head 21. Reference numeral 19 denotes an electrical contact that is connected to the flexible cable 5 and transmits a signal based on the recording data to the recording head 21.

  In FIG. 5, four lines shown on the front surface of the recording head 21 are nozzle rows in which a plurality of nozzles that eject ink are arranged. Bk (black) ink, C (cyan) ink, M (magenta) ink, and Y (yellow) ink are ejected from each of the four nozzle arrays.

  FIG. 6 is a schematic side sectional view for explaining the nozzle structure of the recording head 21. Reference numerals 5102, 5104, 5106, and 5108 denote common liquid chambers that receive inks of respective colors, and correspond to black, cyan, magenta, and yellow inks in this order. The common liquid chambers 5102 to 5108 are formed by anisotropic etching from the rear surface of the heater board 4001 and 4002 on which the semiconductor process is performed, and a liquid path group (5004 or 5005) corresponding to the discharge heater group (5003 or 5005). 5006). Ink supplied to each liquid path is bubbled by abrupt heat generation of the heater based on the recording signal, and a predetermined amount of ink is ejected as droplets from the ejection port toward the recording medium P by this foaming energy. The In this specification, a unit constituted by one heater, one liquid path, and one discharge port is defined as one nozzle.

  FIG. 5 shows that four nozzle rows are arranged on the recording head 21, but in the actual recording head of this embodiment, as shown in FIG. The same color ink is supplied to two nozzle rows arranged on both sides. Here, the left nozzle row, that is, 5004 is referred to as an even nozzle, and the right nozzle row, that is, 5006 is referred to as an odd nozzle, as viewed in FIG. The common liquid chambers and nozzle rows for other colors have the same configuration. However, such a configuration does not characterize the present invention. A configuration may be adopted in which each color ink is ejected from one nozzle row, or a recording head composed of one nozzle row corresponding to only black.

  Reference numerals 5101, 5103, 5105 and 5107 are formed on the base plate 4000 and constitute a common liquid chamber together with the common liquid chambers 5102, 5104, 5106 and 5108. Reference numerals 5001 and 5002 denote orifice plates in which the respective nozzles are formed, and are usually made of a heat resistant resin.

  FIG. 7 is a schematic diagram in which the cap 12 caps the head 1000. As shown, all the cyan, magenta, yellow, and black nozzles are sealed with a single cap 12. An in-cap absorber 7000 is accommodated in the cap 12. A tube is connected to the cap and connected to a pump (not shown). When not printing or turning off the power, the head nozzle portion is capped to prevent the nozzle from drying.

  The ink used in this embodiment has a relatively small amount of water for magenta and yellow and a relatively large amount of water for black and cyan. Although it depends on the ambient humidity, environmental temperature, etc., a density change that can be recognized by leaving for about 120 hours or more occurs. That is, in the cap, magenta and yellow inks are thinned to receive moisture, and black and cyan inks are darkened to release ink.

  Next, the printing mode in this embodiment will be described.

  FIG. 8 is a diagram for explaining a partial screen of the user interface that the information processing apparatus 100 presents to the user. The user can select a medium (recording medium type) used for recording and a recording quality on the screen. In this example, the recording medium can be selected from glossy paper, coated paper, and plain paper. Also, the recording quality can be selected from “fast”, “standard”, and “beautiful”. One of the recording modes shown in Table 1 is set depending on the combination of the type of recording medium and the recording quality. The special paper is set to be larger than the plain paper, and the number of multi-passes is increased as a higher quality image is required even with the same recording medium.

  Table 1 is a table for explaining a recording mode determined by a combination of media and quality in the recording apparatus of the present embodiment.

As shown in the table, the present embodiment has the number of recording passes of 1 pass, 3 passes, 7 passes, and 8 passes. The printing method and mask pattern for each pass number will be described.

[1 pass]
This will be described with reference to FIG. As shown in the figure, a recorded image corresponding to the nozzle width is completed in one scan. Mask processing is not performed on the recording data. After one scan recording, the recording medium is moved in the sub-scanning direction by the nozzle width, and the same operation is repeated.

  In terms of control, the usage frequency of each nozzle is the same.

[3 passes]
This will be described with reference to FIG. As shown in the figure, an image is completed by three scans involving conveyance in the sub-scanning direction of a recording medium having an amount smaller than the nozzle width (about 1/3 of the nozzle width). The dot to be recorded in each scan is determined by the logical sum of the image data and the mask pattern shown in the figure. In terms of control, the nozzle usage frequency depends on the mask pattern, the nozzle center frequency is high, and the nozzle edge frequency is low.

[7 passes]
This will be described with reference to FIG. As shown in the figure, an image is completed by seven scans involving conveyance in the sub-scanning direction of a recording medium having an amount smaller than the nozzle width (about 1/7 of the nozzle width). The dot to be recorded in each scan is determined by the logical sum of the image data and the mask pattern shown in the figure. In terms of control, the nozzle usage frequency depends on the mask pattern, and the nozzle end portion usage frequency is relatively low.

[8 passes]
This will be described with reference to FIG. As shown in the drawing, an image is completed by eight scans involving conveyance in the sub-scanning direction of a recording medium of an amount smaller than the nozzle width (about 1/8 of the nozzle width). The dot to be recorded in each scan is determined by the logical sum of the image data and the mask pattern shown in the figure. For control purposes, the frequency of use of each nozzle is the same.

(Recording operation)
A series of recording operations and preliminary ejection operations in the present embodiment will be described.

  First, mode selection in the recording apparatus will be described with reference to FIG. A recording signal is transmitted from the host computer to the recording apparatus by the host computer operation by the user. At this time, the type of recording medium and the recording quality information are also transmitted at the same time. In the recording apparatus, the recording mode shown in Table 1 is selected based on the type of recording medium and the recording quality.

  Next, details of the operation for each selected recording mode will be described with reference to FIG.

[1-pass printing mode and 8-pass printing mode]
This will be described with reference to FIG.

  Pre-discharge into the cap and feed the paper. Recording data is received from the host computer, and recording is performed by scanning the carriage. At this time, the time from the previous preliminary discharge is counted, and when the predetermined time is reached, the recording of the scan is completed, and then the carriage is moved onto the cap to perform the preliminary discharge. At this time, the number of preliminary ejections is the same for all nozzles (10 in this embodiment). After all the recording data transmitted from the host computer is recorded, the recording operation is terminated.

[3-pass recording mode]
This will be described with reference to FIG.

  Pre-discharge into the cap and feed the paper. Recording data is received from the host computer, and recording is performed by scanning the carriage. At this time, the time from the previous preliminary discharge is counted, and when the predetermined time is reached, the recording of the scan is completed, and then the carriage is moved onto the cap to perform the preliminary discharge. At this time, the number of preliminary ejections of the nozzles near the end is set relatively large, and the number of preliminary ejections of the nozzles in the center is set relatively large. Details of the number of preliminary discharges are shown in FIG. After all the recording data transmitted from the host computer is recorded, the recording operation is terminated.

[7-pass recording mode]
This will be described with reference to FIG.

  Pre-discharge into the cap and feed the paper. Recording data is received from the host computer, and recording is performed by scanning the carriage. At this time, the time from the previous preliminary discharge is counted, and when the predetermined time is reached, the recording of the scan is completed, and then the carriage is moved onto the cap to perform the preliminary discharge. At this time, the number of preliminary ejections of the nozzles near the end is set relatively large, and the number of preliminary ejections of the nozzles in the center is set relatively large. Details of the number of preliminary ejections are shown in FIG. After all the recording data transmitted from the host computer is recorded, the recording operation is terminated.

  The effect of the above operation will be described. When printing is performed using a mask having a different frequency of use in the nozzle row direction, for example, a mask having a high duty at the nozzle center and a low duty at the nozzle end in a state where the ink in the head has a density change, A density difference occurs in the direction, resulting in unevenness. At this time, by performing preliminary discharge that cancels out the difference in use frequency due to the mask, that is, preliminary discharge with a relatively small number of preliminary discharges at the nozzle center and a relatively large number of preliminary discharges at the nozzle end. The occurrence of unevenness can be reduced. This is because by performing the preliminary ejection, it is possible to generate an ink flow different from the ink flow generated in the head liquid chamber during printing. This is because the distribution can be relaxed.

  A schematic diagram of the ink flow in the liquid chamber is shown in FIG. The figure is a sectional view of the head (a sectional view in a direction perpendicular to FIG. 6). FIG. 14A shows the ink flow in the liquid chamber during printing. As can be seen, the ink flow toward the center of the nozzle is strong and the ink flow toward the ink end is small. FIG. 14B shows the ink flow in the liquid chamber during preliminary ejection. As can be seen, the ink flow toward the nozzle end is strong and the ink flow toward the ink center is weak. The flow shown in FIG. 14A is performed during carriage scanning for recording, and the flow shown in FIG. 14B is performed during preliminary ejection. That is, the flows of FIG. 14A and FIG. 14B are alternately generated, and the ink in the liquid chamber can be diffused.

  As described above, it is possible to reduce the occurrence of unevenness even when there is a change in the ink density due to neglect.

[Example 2]
A second embodiment to which the present invention is applicable will be described. Since the recording operation is the same as that of the first embodiment, a description thereof will be omitted.

(Recording operation)
A series of recording operations and preliminary ejection operations in the second embodiment will be described.

  First, as in the first embodiment, the recording mode is selected according to the flow of FIG. Details of the operation for each selected recording mode will be described with reference to FIGS.

[1-pass printing mode and 8-pass printing mode]
This will be described with reference to FIG. The same as in the first embodiment.

  Pre-discharge into the cap and feed the paper. Recording data is received from the host computer, and recording is performed by scanning the carriage. At this time, the time from the previous preliminary discharge is counted, and when the predetermined time is reached, the recording of the scan is completed, and then the carriage is moved onto the cap to perform the preliminary discharge. At this time, the number of preliminary ejections is the same for all nozzles (10 in this embodiment). After all the recording data transmitted from the host computer is recorded, the recording operation is terminated.

[3-pass recording mode]
This will be described with reference to FIG.

  When the elapsed time from the previous recording exceeds 120 hours, the preliminary ejection during printing shown in FIG. If it is 120 hours or less, it is determined that the image deterioration due to the dye density change in the head is an acceptable level, and the preliminary ejection during printing is the same number of shots (10 shots in this embodiment) for all nozzles.

[7-pass recording mode]
This will be described with reference to FIG.

  When the elapsed time from the previous recording exceeds 120 hours, the preliminary ejection during printing shown in FIG. If it is 120 hours or less, it is determined that the image deterioration due to the dye density change in the head is an acceptable level, and the preliminary ejection during printing is the same number of shots (10 shots in this embodiment) for all nozzles.

  By branching the processing based on the elapsed time from the previous recording, it is possible to suppress the number of preliminary ejections during printing when the change in the dye density is at an acceptable level, so that ink is not unnecessarily wasted.

  The time of 120 hours is a parameter changed by the system. It is preferable to set optimum parameters according to the surrounding environment such as ink characteristics, head characteristics, cap sealing characteristics, temperature and humidity. In this embodiment, the determination is made based on the elapsed time from the previous recording. However, since the dye density change occurs in the cap, the determination may be made based on the total time of capping from the previous recording to the current recording. .

100 Information processing device (host computer)
200 Recording device

Claims (4)

A multi-pass means for performing multi-pass printing using a mask having a relatively high duty at the center of the nozzle row and a relatively low duty at the end of the nozzle row, and when a predetermined time elapses during printing, Preliminary ejection means for performing preliminary ejection, and the predetermined pattern is characterized in that the number of preliminary ejections at the center of the nozzle is relatively large and the number of preliminary ejections at the nozzle end is relatively small. Inkjet recording device. The first multi-pass means for performing multi-pass printing using a mask having a relatively high duty at the center of the nozzle row and a relatively low duty at the end of the nozzle row, and using a mask with an equal duty for all nozzles A second multi-pass means for performing multi-pass recording; and a pre-discharge means for performing a pre-discharge of a predetermined pattern when a predetermined time has elapsed during printing, the predetermined pattern being a first multi-pass means. When recording with the second multi-pass means, the number of preliminary ejection at the center of the nozzle is relatively large, the number of preliminary ejection at the nozzle end is relatively small, An ink jet recording apparatus, wherein each nozzle has a substantially equal number of preliminary ejections. The inkjet recording apparatus according to claim 1, further comprising a cap that integrally seals the multi-color nozzle rows. 4. The pre-discharge predetermined pattern is changed according to any one of claims 1 to 3, when the recording is performed, when the elapsed time from the previous recording exceeds a predetermined time and when it is equal to or shorter than the predetermined time. The ink jet recording apparatus described.