JP2007237673A - Ink-jet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always maintain a good image quality and suppress an increase in printing time and increase in an ink consumption amount to minimum levels. <P>SOLUTION: Before printing in a back direction, total printing time required for back and forth printing for which wait time is taken into consideration is calculated. In accordance with the time, whether preliminary discharge is to be carried out before back and forth printing and standby preliminary discharge is to be carried out is determined. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to optimization of preliminary ejection timing of the ink jet recording apparatus and a control method thereof.

  The ink jet recording apparatus is configured to form an image by ejecting ink droplets from a recording head having a plurality of ink ejection openings and attaching them to a recording medium. The ink discharge ports are arranged in a direction parallel to the conveyance direction of the recording medium.

  As a scanning method of an ink jet recording apparatus, a method called serial scanning is often adopted, and in this serial scanning method, a recording head mounted on a carriage intersects with a conveyance direction (sub-scanning direction) of a recording medium. By repeating the operation of scanning in the direction, feeding a predetermined amount of paper after completing the recording for one scan, and then recording the image for the next one scan on the recording medium stopped again, Recording is performed on the entire recording medium.

  In the above-described ink jet recording apparatus, variations occur in the usage frequency of the ejection ports of the recording head during the printing operation. Therefore, some of the ejection ports of the recording head are not used for a certain period of time during recording. If the ink is left in the air for a long time with the ink filled in the ejection port, the ink viscosity will rise due to precipitation of the components that make up the ink and evaporation of the water, resulting in poor printing such as twisting and ejection, There is a problem that clogging occurs and discharge failure occurs.

  In the above ink jet recording apparatus, dust and bubbles are mixed in the ink supply system from the ink tank to the recording head, and are guided to the liquid path of the recording head to adhere to the liquid path, thereby inhibiting the ink flow. In addition, ink ejection efficiency may be reduced, or clogging may occur in severe cases.

  Therefore, in order to avoid these problems, a method of executing a preliminary ejection operation in which a small amount of ink is ejected in advance immediately before printing is employed.

Preliminary ejection is performed at the ink receiving section provided outside the recording area at the timing determined based on the start of each scan, a predetermined time interval during execution of the printing operation, the usage rate of the ink ejection port, etc., and the ink consumption and recording Patent Documents 1 and 2 disclose a control method for making time compatible.
JP2001-205823 JP2004-82629

  In the prior art, optimization is performed by a method of selecting the execution of preliminary ejection by comparing the printing time required for printing for the next one scan with the time until the next preliminary ejection every time one printing is performed. It has been.

  However, when the amount of image data to be handled is large as in a large format printer, a wait operation depending on the transfer time may occur. In such a case, the conventional calculation method may cause a deviation from the actual comparison time.

  Further, when the wait time becomes longer, the carriage moves onto the preliminary ejection receptacle, and a standby preliminary ejection operation is performed in which the preliminary ejection is periodically performed on the preliminary ejection receptacle to prevent an increase in the viscosity of the ink in the nozzles.

  Since this standby preliminary ejection is performed by preliminary ejection outside the printing area, it takes time to move to a predetermined location, leading to an increase in printing time.

  The present invention has been made in consideration of the above-described problems, and provides an ink jet recording apparatus and a control method for the ink jet recording apparatus in which a reduction in printing speed and an ink consumption amount are minimized while maintaining a good image quality.

  In one embodiment of the present invention, the printing time required for reciprocal printing is calculated at the time of reverse scanning in the forward direction, and the total time required for reciprocal printing is calculated from the value obtained by adding the wait time. Then, an ink jet recording apparatus and a preliminary ejection control method that perform optimum printing by selecting an appropriate preliminary ejection method according to the time at the start of printing in the backward direction are proposed.

  In the present invention, by selecting an appropriate preliminary discharge means at the start of printing in the backward direction, it is possible to perform high-quality printing with a minimum printing time and ink consumption.

<Embodiment 1>
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing the entire inkjet recording apparatus of the present invention.

  In FIG. 1, a paper feed roller 101 sandwiches the recording medium 102 between a pair of rollers, and moves the recording medium in the sub-scanning direction by rotating. The recording head has an ejection port on the surface facing the platen 106. The recording head 105 is detachably attached to the carriage 104, and the carriage is moved along the main scanning guide 103 by carriage driving means (not shown), so that the recording medium is scanned (hereinafter referred to as "main scanning"). Ink droplets can be ejected. The recording head is coupled to an ink supply device (not shown) and is supplied with ink. The platen 106 is provided under the ink recording head. During recording, the recording medium is positioned between the platen and the recording head, and is held by the platen 106 so that the interval between the recording medium and the recording head is appropriate. Retained. Although not shown in FIG. 1, this ink jet recording apparatus has a recording medium supply means for supplying the recording medium to the paper feed roller, a recovery means for maintaining the state around the ejection opening of the recording head, and recording. A recording medium discharge means for taking out the finished recording medium is provided.

  The recording operation is performed as follows.

  When a recording start command signal is input to this ink jet recording apparatus, a recording medium is supplied from a recording medium supply means (not shown) from the upper right direction in FIG. 1 until the tip comes to the position of the paper feed roller, In response to the recording signal, the recording medium is fed by the paper feed roller so that the recording head is positioned at the printing start position on the recording medium. Subsequently, printing is performed by spraying ink droplets onto the recording medium while the carriage and the recording head perform main scanning. Thereafter, a predetermined amount of recording medium is fed by a paper feed roller (this operation is hereinafter referred to as “sub-scanning”), and ink droplets are sprayed onto the recording medium again while the carriage and recording head perform main scanning. . After recording is performed on the recording medium by repeating this sub-scanning and main scanning, the recording medium is discharged in the lower left direction in FIG. Note that paper is often used as the recording medium, but other materials may be used. Further, in the case of an OHP sheet, a compact disk, and a DNA chip manufacturing apparatus and a display manufacturing apparatus using an ink jet, a substrate made of a material suitable for each may be used.

  Although not shown, the inkjet recording apparatus according to the first embodiment includes a control unit configured by a CPU, a ROM, a RAM, and a dedicated circuit that control and execute recording and image processing. Furthermore, an interface unit for exchanging image information and various control information with an external computer or the like is also provided. Also provided is a printhead drive driver for driving a carriage motor for driving the carriage, a paper feed motor for driving the paper feed roller, a paper transport motor for driving the paper transport, and the like. An operation panel for inputting control information by the user is also provided.

  Various pre-discharge methods implemented in the present invention will be described.

  Along with the movement of the carriage according to the print command, the preliminary discharge before the forward printing is performed on the preliminary discharge receiver 107 immediately before the start of the forward printing.

  After the carriage stops and before the start of the reverse return printing, if necessary, the preliminary discharge before the return print is placed on the borderless printing hole installed outside the printing area (not shown) or on the platen. Do.

  The position of the preliminary discharge before the return pass printing is determined according to the size of the recording medium.

  When data transfer takes a long time or when there is no print command for a certain period of time in the manual pause state, the carriage moves to the preliminary discharge outside the print area and continues the preliminary discharge until it receives a print command again This operation is called standby preliminary discharge.

  Next, the preliminary ejection method of the present invention will be described with reference to the flowchart of FIG.

  From step S201, the carriage scanning speed is determined by determining the printing conditions.

  In response to the print command, in step S202, the print area is detected from the image data for one scan of the print, and the movement distance of the carriage is known accordingly.

  In step S203, preliminary ejection before printing is performed, and printing in the forward direction is started.

  When the forward printing is completed, the carriage stop time from the step S204 to the start of the backward printing, that is, the wait time ta is measured.

  In step S205, a time T required for the carriage to reciprocate is calculated before starting the return pass printing.

  The calculation method of T is shown below.

  From the scanning speed v (inch / sec) determined in S201 and the printing area r (inch) detected in S202, the forward printing time tb is obtained by r / v.

The time required for the return pass printing is the same as the time tb required for the forward pass, so that T = ta + 2tb together with the wait time
This value T is compared with the threshold value set in advance in step S206.
Here, the threshold A is a value set to a time during which the ink in the nozzle can be printed without causing defective ejection.

  The threshold value B is a value set to shift to standby preliminary discharge, and A <B.

  The thresholds A and B are different values depending on the type of ink and the ejection conditions, and do not take particular values.

  It is assumed that the value varies depending on the maximum print width of the printer.

  FIG. 4 shows threshold values A and B in this embodiment.

  From step S206, if there is a print command, the process proceeds to step S207, and compared with the threshold A. If T ≦ A, the process proceeds to step S208, and the backward print is started without performing the preliminary discharge in the reverse direction.

  In this case, printing is completed in a time when no ejection failure occurs. That is, since the reciprocal printing can be performed in a time shorter than the time required for the preliminary ejection in the backward direction, the backward printing is started without performing the preliminary ejection in the backward direction.

  From step S206, if there is no print command, the value of T is periodically calculated according to step S209 until there is a print command.

  When T ≧ B is reached from step S209, the process proceeds to step S210 to move to a predetermined preliminary discharge position and perform standby preliminary discharge.

  If a print command is received in accordance with step S211, the process proceeds to step S212, and the return pass printing is performed after the return pass preliminary discharge is performed.

  If A <T <B from steps S206 and S207, the process proceeds to step S212 to perform preliminary ejection before the return pass printing at a predetermined position and resume printing.

  When printing in the backward direction is finished, the process proceeds to step S213, and the timer and the value of T are reset.

  According to step S214, if there is a print command, the above operation is repeated.

  By repeating the above printing for each scan, it is possible to perform printing with a reduction in printing speed and a minimum ink consumption while maintaining a good image quality.

<Embodiment 2>
In the above-described embodiment, the carriage scanning time is calculated, but there is a method in which the carriage scanning time is also measured by a timer.

  Hereinafter, the second embodiment of the present invention will be described with reference to the flowchart of FIG.

  When print data is received in step S301, the process proceeds to step S302 to perform preliminary discharge before printing. The timer is started in step S303 from the time when the preliminary ejection starts, and the time from when the forward printing is finished, that is, the time until the carriage stops when the carriage is reversed, is measured as the time tc required for the forward printing.

  When the carriage is stopped, the process proceeds to step S304, the wait time is measured, and the process proceeds to step S305, where the print time T ′ is calculated.

  The method for calculating T ′ is shown below.

  The time required for printing in the backward direction is the same as the time required for forward printing and is time tc.

  Measure the time from the carriage stop to the time printing restart, and let this be td.

That is, the printing time T ′ required for reciprocation is T ′ = td + 2tc
Is calculated as

  From step S306, if there is a print command, the process proceeds to step S307, and compared with the threshold value A. If T ′ ≦ A, the process proceeds to step S308, and the backward print is started without performing preliminary discharge in the reverse direction.

  In this case, printing is completed in a time when no ejection failure occurs. That is, since the reciprocal printing can be performed in a time shorter than the time required for the preliminary ejection in the backward direction, the backward printing is started without performing the preliminary ejection in the backward direction.

  From step S306, when there is no print command, according to step S309, the value of T ′ is calculated periodically until there is a print command.

  When B ≦ T ′ is reached from step S309, the process proceeds to step S310 to move to a predetermined preliminary discharge position and perform standby preliminary discharge.

  If a print command is received in accordance with step S311, the process proceeds to step S312 to perform return pass printing after performing return pass preliminary discharge.

  If A <T ′ <B from Steps S306 and S307, the process proceeds to Step S312 to perform preliminary discharge before the return pass printing at a predetermined position and restart printing.

  When printing in the backward direction is finished, the process proceeds to step S313, and the timer and the value of T are reset.

  According to step S314, if there is a print command, the above operation is repeated.

  By repeating the above printing for each scan, it is possible to perform printing with a reduction in printing speed and a minimum ink consumption while maintaining a good image quality.

  The above method is particularly effective when performing control in which the scanning speed is changed according to image data.

(Other)
The present invention is provided with means (for example, an electrothermal converter, a laser beam, etc.) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system, and the ink is generated by the thermal energy. In the recording head and the recording apparatus of the type that causes the state change, excellent effects are brought about. This is because such a system can achieve high recording density and high definition.

  This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface of the liquid and, as a result, bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness.

  In addition, a recording head fixed to the apparatus main body, or a replaceable chip type recording head that can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body. Alternatively, the present invention is also effective when a cartridge type recording head in which an ink tank is provided integrally with the recording head itself is used.

  Also, regarding the type or number of recording heads to be mounted, for example, a plurality of recording heads are provided corresponding to a plurality of inks having different recording colors and densities, in addition to one provided corresponding to a single color ink. May be used. That is, for example, as a recording mode of the recording apparatus, not only a mainstream color recording mode such as black, but also a recording head may be configured integrally or a plurality of combinations may be used. Alternatively, the present invention is extremely effective for an apparatus having at least one of full-color recording modes by color mixing.

  In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, ink that is solidified at room temperature or lower and that softens or liquefies at room temperature may be used. In the ink jet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that it is in the stable discharge range. A liquid material may be used. In addition, it is solidified and heated in an untreated state in order to actively prevent the temperature rise caused by thermal energy from being used as the energy for changing the state of the ink from the solid state to the liquid state, or to prevent the ink from evaporating. You may use the ink which liquefies by. In any case, by applying thermal energy according to the application of thermal energy according to the recording signal, the ink is liquefied and liquid ink is ejected, or when it reaches the recording medium, it already starts to solidify. The present invention can also be applied to the case of using ink having the property of liquefying for the first time. In the present invention, the most effective one for each of the above-described inks is to execute the above-described film boiling method.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. The thing etc. may be sufficient.

1 is a perspective view schematically showing a configuration of a main part of an ink jet recording apparatus according to the present invention. It is a flowchart which shows the procedure of 1st Embodiment about the preliminary discharge control operation | movement in this invention. It is a flowchart which shows the procedure of 2nd Embodiment about the preliminary discharge control operation | movement in this invention. It is a figure for demonstrating the value of the threshold values A and B in a present Example.

Explanation of symbols

101 Paper feed roller
102 Recording media
103 Main scan guide
104 Carriage
105 Recording head
106 Platen
107 Pre-discharge

Claims (4)

Using an ink discharge head in which a plurality of ink discharge ports are arranged, ink is discharged while scanning the ink discharge head in a direction different from the ink discharge port, and recording is performed on a recording medium. An ink jet recording apparatus that performs a preliminary discharge operation of moving the ink discharge head to a position facing a preliminary discharge receiver provided outside an area and discharging ink from the plurality of ink discharge ports to the preliminary discharge receiver. In an inkjet recording apparatus having means for detecting the time required for printing scan and means for measuring the wait time when the carriage is reversed, the printing time required for reciprocation before the start of the return pass printing is calculated, and a preliminary value is set according to the calculated value. An ink jet recording apparatus, wherein a discharging means is selected. Using an ink discharge head in which a plurality of ink discharge ports are arranged, ink is discharged while scanning the ink discharge head in a direction different from the ink discharge port, and recording is performed on a recording medium. An ink jet recording apparatus that performs a preliminary discharge operation in which the ink discharge head is moved to a position facing a preliminary discharge receiver provided outside an area and ink is discharged from the plurality of ink discharge ports to the preliminary discharge receiver.
Compare the print time calculated when reversing one scan with the set value,
If the calculated value is less than or equal to the first set value, the preliminary discharge before the return pass printing is not performed.
If the calculated value is greater than or equal to the second set value, standby preliminary discharge is performed,
2. The ink jet recording apparatus according to claim 1, wherein when the obtained calculated value is a value between the first set value and the second set value, preliminary ejection is performed before printing on the return path side. Detects the print area from the image data, calculates the print time from the moving speed from the scan speed determined by the print conditions,
2. The ink jet recording apparatus according to claim 1, wherein the print time is calculated by measuring the wait time with a timer device provided in the main body. A first timer device for measuring a carriage scanning time;
A second timer device for measuring the carriage wait time in the main body;
The inkjet recording apparatus according to claim 1, wherein the printing time is calculated using the first and second timers.

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