JP2004001411A - Inkjet recorder and method of inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder and a method of inkjet recording that can always obtain a high quality output with high reliability by suppressing density variation of an ink in an ink supply passage or a recording head without performing a waste recovery operation. <P>SOLUTION: This inkjet recorder that performs the recording by using a recording head for ejecting ink, comprises a moving means for moving the recording head to scan a recording medium, a measuring means for measuring a time period from completion of the recording operation of the recording head to starting of the previous operation thereof, and a judging means for judging whether or not the time period measured by the measuring means exceeds a predetermined time period. The moving means moves the recording head idly before the starting of the recording operation according to the result judged by the judging means. <P>COPYRIGHT: (C)2004,JPO

Description

【００６４】
以上述べたように本発明では、前回の記録動作終了時から今回の記録動作開始時までの経過時間を直接的に取得しても間接的に取得してもよい。要は、前回の記録動作終了時から今回の記録動作開始時までの時間に対応した情報を取得できればよく、この場合、前回の記録動作終了時から今回の記録動作開始時までの時間に対応した情報を取得し、当該取得した情報に応じて空スキャンの実行有無やその回数を決定すればよいのである。
【００６５】
（その他の実施形態）
実施形態１や２をさらに発展させ、インクタンクの攪拌手段を組み合わせたりすることも可能である。インクタンクの攪拌手段としては前述した従来例のようにチューブに設けられた弁を動作させてインクの流れを発生させることや、タンクの中に羽等の攪拌機構を設けてあっても構わない。この場合、前回の記録動作からの時間間隔に応じて空スキャンと攪拌を合わせて行っても良いし、また、時間間隔の長さに応じて組み合わせて行ってもよい。
【００６６】
本実施形態ではチューブ等の流路を有するインクジェット記録装置について説明したが、流路を持たないインクジェット記録装置であっても、本発明により記録ヘッド内の液室におけるインク濃度の不均一を緩和できることは言うまでもない。
【００６７】
【発明の効果】
以上説明したように本発明によれば、前回の記録動作時からの経過時間に対応した情報に基づき空スキャンを実行するために、供給チューブ内と記録ヘッド内のインクの濃度が不均一になっている状態を記録動作前に緩和することができるので、高品位な画像を出力することができるとともに濃度の高いインクによる吐出特性の悪化を防止することができる。
【００６８】
また、時間間隔に応じて空スキャンの実施回数を異ならせるので、より効果的で信頼性の高い吐出特性の回復が図れる。
【図面の簡単な説明】
【図１】本発明に係るインクジェット記録装置の概略図である。
【図２】図１のインクジェット記録装置におけるインク供給系の概略図である。
【図３】図１のインクジェット記録装置における電気回路の全体構成の概略図である。
【図４】図１のインクジェット記録装置におけ概略制御ブロック図である。
【図５】
第１の実施形態における記録動作を説明する図である。
【図６】
第２の実施形態における記録動作を説明する図である。
【図７】
記録ヘッドとインクタンクをチューブで結んだインクジェット記録装置の概略図である。
【符号の説明】
１　　　記録ヘッド
２　　　キャリッジ
３　　　供給チューブ
４　　　大気連通チューブ
５　　　インクタンク
１２　　キャリッジモータ
１３　　フレキシブルケーブル
１４　　回復手段
１５　　給紙トレイ
１６　　光学位置センサ
２１　　キャップ
２２　　吐出受け
２３　　ワイパーブレード
２０１　メインタンク
２０２　サブタンク
２０３　バッファ室
２０７　チューブ
２０８　ジョイント
３０１　キャリッジ基板
３０２　メインＰＣＢ
３０３　電源ユニット
３０４　コンタクトＦＰＣ
３０５　エンコーダセンサ
３０６　エンコーダスケール
３０８　紙端検出センサ（ＰＥセンサ）
３０９　ＡＳＦセンサ
３１０　カバーセンサ
３１１　パラレルインターフェース（パラレルＩ／Ｆ）
３１２　リジュームキー
３１３　ＬＥＤ
３１４　電源キー
３１５　ブザー
３１６　ＣＲモータ
３１７　ＬＦモータ
３１８　ＰＧモータ
３１９　ＰＧセンサ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet recording apparatus and an inkjet recording method, and more particularly to an inkjet recording apparatus and an inkjet recording method using a pigment ink.
[0002]
[Prior art]
2. Description of the Related Art In recent years, inkjet recording apparatuses such as printers, facsimile machines, and copiers using an inkjet recording method have been rapidly expanding into the market.
[0003]
This ink jet recording apparatus comprises a recording head for discharging ink droplets and an ink tank for supplying ink to the recording head. Among them, in the case where the recording head and the ink tank are integrated, when the ink in the ink tank runs out, the recording head also needs to be replaced, so that the consumables are increased, and as a result, the running cost is increased.
[0004]
Therefore, the mainstream is configured such that the recording head and the ink tank are separately configured, and even if the ink in the ink tank runs out, only the ink tank needs to be replaced. In this case, the running cost is lower than that in which the recording head and the ink tank are integrally formed, but if the running cost is to be further reduced, the capacity of the ink tank must be increased. In addition, in a case where a large amount of ink is used for one recording, such as a large-format printer that performs recording on a recording medium (recording paper) having a large size such as A0 or B0, printing can be performed per ink tank. If the number of sheets is not large enough, the frequency of replacement of the ink tanks increases and it becomes cumbersome.
[0005]
When the capacity of the ink tank is increased, the carriage for performing the serial scan for printing by mounting the print head and the ink tank becomes larger and heavier. When the carriage is heavy, it becomes difficult to scan the carriage at a high distance. Even so, if scanning is performed at high speed, an expensive motor having torque must be used, which leads to an increase in the cost of the apparatus.
[0006]
Therefore, the ink tank is not mounted on the scanning carriage, but is fixed at a predetermined location in the ink jet recording apparatus. Only the recording head is mounted on the carriage, and a tube is provided between the recording head and the ink tank. Recording devices connected by such means have also been put to practical use. In the case of this apparatus, it is necessary to connect the recording head and the ink tank with a member such as a tube. However, since only the recording head is mounted on the carriage, it is light in weight and can perform high-speed scanning. Further, since the capacity of the ink tank can be increased as needed, the capacity may be set in consideration of the running cost, the size of the apparatus, the frequency of ink tank replacement, and the like.
[0007]
FIG. 7 is a schematic configuration diagram of a recording apparatus in which a recording head and an ink tank are connected by a tube. 1 is a recording head mounted on a carriage (not shown), 5 is an ink tank, 3 is a supply tube connecting the recording head 1 and the ink tank 5, and 4 is an atmosphere communication tube. When printing is performed by the recording head 1, the ink in the ink tank 5 is supplied from the ink tank 5 to the recording head 1 via the supply tube 3. On the other hand, air is supplied from the atmosphere communication tube 4 by an amount supplied. According to this configuration, the size of the ink tank can be freely set according to the application. Therefore, when it is assumed that the amount of used ink is large like a large format printer or a network printer, it is possible to set the ink tank large. Good.
[0008]
In recent years, there has been an increasing demand for recording a poster or the like posted outdoors as one of the uses of a large format printer. Therefore, weather resistance is required as a condition of a recorded material (printed on recording paper) for posting outdoors, but a dye ink conventionally used generally in an ink jet recording apparatus has insufficient weather resistance. there were. Particularly with respect to light resistance and gas resistance, there is a problem that the dye changes with time and the color is remarkably faded. Although the dyes have been improved recently and the weather resistance has been improved under relatively favorable conditions such as indoors, it can be said that the level is still far from the level that can be used outdoors. In the case of a large format, the recorded matter may be laminated to form a notice, but the gas resistance is improved, but the light resistance is not at a practical level.
[0009]
[Patent Document 1]
JP-A-8-281967
[0010]
[Problems to be solved by the invention]
Therefore, in recent years, those using pigment ink instead of dye ink have been put to practical use. Usually, the dye ink dissolves the dye in the solution, while the pigment ink disperses the pigment particles in the solution. The long-term dispersion stability of the pigment particles is a very important factor for a recording apparatus that can always obtain high-quality output with high reliability. The dispersion stability of a pigment greatly affects the type and composition of a dispersant such as a resin and an activator used for dispersion, but it is very difficult to obtain a pigment that does not change over a long period of time. Normally, if the pigment ink is left for a long time, the pigment concentration in the pigment ink will not be constant. For example, since the pigment concentration differs between the upper part and the lower part of the ink tank, when used in that state, the result is that the concentration differs as compared with the case where the pigment is uniformly dispersed.
[0011]
If the device is not used for a long period of time, the dispersibility can be improved to some extent by performing a recovery operation using a pump or the like, but it is not sufficient. Also, wasting more ink by the recovery operation leads to an increase in running cost, and furthermore, the amount of waste ink increases, so that the volume for storing waste ink in the recording apparatus increases, and the size of the apparatus increases. This leads to an increase in the cost of the device.
[0012]
Therefore, the applicant of the present application has developed a recording apparatus that, when not used for a long time, creates a flow of ink by operating a valve provided in a tube for supplying ink, thereby mitigating a density change in an ink tank. Proposed.
[0013]
In this recording apparatus, it is possible to make the density in the ink tank uniform, but it is insufficient to reduce the change in density in the tube or the recording head. It is difficult to eliminate the non-uniform density in the recording head only by preliminary ejection before the start of recording, and even if high-density ink can be ejected in a portion close to the nozzle, low-density ink remains in the recording head. Therefore, the quality of the recorded image is degraded.
[0014]
Patent Document 1 discloses an apparatus in which the configuration of the tube is devised or a projection is provided in the tube in order to reduce a change in the concentration of ink in the supply tube. In such a device, the degree of freedom in design is reduced, and a normal tube cannot be used, so that the device becomes complicated and cost increases.
[0015]
Therefore, the present invention has been made to improve the above-mentioned problems, and has been made to improve the ink supply path and the ink in the recording head without performing useless recovery operation and without complicating the configuration of the supply tube. It is an object of the present invention to provide an ink jet recording apparatus and an ink jet recording method which can alleviate a change in density of an ink jet recording and can always obtain high quality output with high reliability.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, an inkjet recording apparatus of the present invention is an inkjet recording apparatus that performs recording using a recording head for discharging ink, wherein a scanning unit that scans the recording head against a recording medium is provided. Measuring means for measuring the time from the end of the previous recording operation to the start of the current recording operation, and determining means for determining whether the measurement result by the measuring means has exceeded a predetermined time, The scanning unit performs an idle scan of the recording head before starting a recording operation, according to a result of the determination by the determining unit.
[0017]
Further, a plurality of different predetermined times are provided as the predetermined time used in the determination by the determining means, and the determining means performs the determination in a plurality of stages according to the plurality of different predetermined times. Is preferably performed.
[0018]
Furthermore, it is preferable that the scanning unit changes the number of the empty scans according to the length of time measured by the measuring unit. Here, it is preferable that the scanning unit increases the number of times of the empty scan when the length of time measured by the measuring unit is relatively long, as compared with the case where the length is relatively short. Further, it is preferable that the scanning unit performs the idle scan at a speed higher than the scan speed of the normal scan for scanning the recording head while discharging the ink.
[0019]
Furthermore, it is preferable that the ink is a pigment ink.
[0020]
Furthermore, an ink tank for storing the ink is provided, and the recording head and the ink tank are connected via a tube flow path for supplying the ink.
[0021]
Furthermore, the ink tank is provided with stirring means for stirring the ink in the empty scan as well as the empty scan.
[0022]
Further, the present invention provides an ink jet recording apparatus which performs recording using a recording head for discharging ink, a scanning unit for scanning the recording head with respect to a recording medium, Acquiring means for acquiring information corresponding to the time until the start of the recording operation, and determining means for determining whether or not to cause the recording head to perform idle scanning before the start of the recording operation, according to the information acquired by the acquiring means. It is characterized by having.
[0023]
Further, the present invention provides an ink jet recording apparatus which performs recording using a recording head for discharging ink, a scanning unit for scanning the recording head with respect to a recording medium, Acquisition means for acquiring information corresponding to the time until the start of the recording operation, and determination means for determining the number of empty scans to be executed before the start of the recording operation, according to the information acquired by the acquisition means. It is characterized by the following.
[0024]
An inkjet recording method according to the present invention is the inkjet recording method in which recording is performed using a recording head that ejects ink, wherein a scanning step of scanning the recording head with respect to a recording medium, A measuring step of measuring a time until a recording operation is started, and a determining step of determining whether or not a measurement result of the measuring step has exceeded a predetermined time, wherein the scanning step includes a determination result of the determining step. And causing the print head to perform an idle scan before the start of a printing operation.
[0025]
Also, the present invention provides an inkjet recording method for performing recording using a recording head for discharging ink, wherein a scanning step of scanning the recording head with respect to a recording medium, An acquisition step of acquiring information corresponding to a time until the start of a recording operation, and a determining step of determining whether to cause the recording head to perform idle scanning before the start of a recording operation, according to the information acquired in the acquisition step. It is characterized by having.
[0026]
Also, the present invention provides an inkjet recording method for performing recording using a recording head for discharging ink, wherein a scanning step of scanning the recording head with respect to a recording medium, An acquisition step of acquiring information corresponding to the time until the start of the recording operation, and a determining step of determining the number of empty scans to be executed before the start of the recording operation, according to the information acquired in the acquisition step. It is characterized by the following.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0028]
In this specification, the “blank scan” refers to an operation of scanning the print head without discharging ink from the print head.
[0029]
Further, in this specification, “time (elapsed time) from the end of the previous printing operation to the start of the current printing operation” means (1) after the end of ink discharge by the print head accompanying the previous printing operation. The time until the printing apparatus receives a print operation start signal for the next print operation, or (2) the discharge port surface of the print head to be executed after the end of ink discharge by the print head in the previous print operation. It refers to the time from the operation of covering with the cap (cap closing operation) to the operation of separating the ejection opening surface of the recording head from the cap for the next recording operation (cap opening operation).
[0030]
Further, the “end of ink ejection by the print head accompanying the previous printing operation” may refer to the end of ink ejection by the print head based on image data for image formation, or based on image data. It may indicate the end of the preliminary ejection of the ink from the recording head to the recovery unit, which is executed after the end of the ink ejection by the recording head.
[0031]
FIG. 1 is a schematic diagram of a main part of an inkjet recording apparatus (hereinafter, also referred to as a printer) to which the present invention can be applied. This ink jet recording apparatus is a so-called serial scan type recording apparatus, and forms an image by scanning the ink jet recording head in a direction (main scanning direction) orthogonal to the transport direction of the recording medium (sub scanning direction). Record.
[0032]
A carriage 2 on which an ink jet recording head (hereinafter, also simply referred to as a recording head) is mounted, a carriage motor 12 for moving the carriage in the main scanning direction, and a flexible cable for sending an electric signal from a control unit (not shown) of the printer to the recording head. 13, a recovery means 14 for performing a print head recovery process, a paper feed tray 15 for storing printing paper as a recording material in a stacked state, an optical position sensor 16 for optically reading the position of the carriage, and the like. . The ink jet recording apparatus having such a configuration performs serial scanning of the carriage 2 to perform printing with a width corresponding to the discharge ports (number of nozzles) of the recording head, and intermittently conveys a predetermined amount of recording paper during non-printing. .
[0033]
Further, in the enlarged view of the recovery means 14, reference numeral 21 denotes a suction and protection cap. The cap 22 covers the discharge port surface of the recording head during the non-printing operation, and opens the discharge port surface of the recording head during the recording operation. It is. Reference numeral 22 denotes an ejection receiver for receiving the ink ejected during ejection recovery, and reference numeral 23 denotes a wiper blade for wiping the face surface while wiping the face surface while moving in the direction of the arrow.
[0034]
FIG. 2 is a diagram illustrating a recording apparatus in which a recording head and an ink tank are connected by a tube.
[0035]
The ink is supplied from the main ink tank 201 to the sub ink tank 202 on the carriage 2 via the tube 207 and the joint 208, and then supplied to the recording head 1. In the main ink tank 201, 201Y, 201M, 201C, and 201B are storage units for yellow, magenta, cyan, and black inks, respectively. The recording head 1 moves in the main scanning direction along the shaft 10 together with the carriage 2. 203 is a buffer room.
[0036]
The ink may be directly supplied to the recording head 1 from the main tank 201 provided at a fixed position of the apparatus main body. However, in order to reduce the load applied to the carriage 2 and achieve high-speed printing and reduction in size and weight, it is effective to reduce the size of the sub tank 202 mounted on the carriage 2 as in this example. That is, a relatively small-capacity sub-tank 202 is mounted on the carriage 2 to supply ink to the recording head 1 from the sub-tank 202, and a relatively fixed sub-tank 202 is fixed to a predetermined position of the apparatus body with respect to the sub-tank 202. A configuration in which ink is supplied from the large-capacity main tank 201 is effective for high-speed recording and reduction in size and weight. The supply joint 208 forms an ink supply path between the main tank and the sub tank when the carriage 2 moves to a predetermined position such as a home position. Therefore, ink can be supplied from the main tank 201 to the sub-tank 202 at an optimal time according to the capacity of the sub-tank 202 and the ink consumption of the recording head 1.
[0037]
FIG. 3 is a diagram schematically showing an overall configuration of an electric circuit according to this embodiment.
[0038]
The electric circuit in this embodiment mainly includes a carriage substrate 301, a main PCB (Printed Circuit Board) 302, a power supply unit 303, and the like. Here, the power supply unit is connected to the main PCB 302 and supplies various driving powers. The carriage substrate 301 is a printed circuit board unit mounted on the carriage 2 (FIG. 1), functions as an interface for transmitting and receiving signals to and from the recording head through the contact FPC 304, and also has an encoder sensor 305 as the carriage moves. , A change in the positional relationship between the encoder scale 306 and the encoder sensor 305 is detected, and the output signal is output to the main PCB 302 through the flexible flat cable (CRFFC) 302.
[0039]
Further, a main PCB is a printed circuit board unit that controls the driving of each unit of the ink jet recording apparatus in this embodiment, and includes a paper edge detection sensor (PE sensor) 308, an ASF sensor 309, a cover sensor 310, and a parallel interface (parallel I / F). ) I / O ports for 311, resume key 312, LED 313, power key 314, buzzer 315, etc. are provided on the board, and further connected to CR motor 316, LF motor 317, PG motor 318 to control their driving. It also has a connection interface with the PG sensor 319, CRFFC 307, and power supply unit 303.
[0040]
FIG. 4 is a block diagram of a main PCB of the recording apparatus according to the present embodiment. In the figure, reference numeral 401 denotes a CPU, which is connected to a ROM 402 and an ASIC (Application Specific Integrated Circuit) 403 through a control bus, and controls the ASIC, an input signal 404 from a power key, and a resume key in accordance with a program stored in the ROM. , A cover detection signal 406, and various logic operations and conditions such as driving a buzzer 407 in response to a buzzer signal (BUZ). In addition, the CPU 401 has a function of measuring the time from the last recording operation described later to the present recording operation by software.
[0041]
A CR motor driver 408 generates a CR motor drive signal in accordance with a CR motor control signal from the ASIC 403, and drives the CR motor 409. An LF / PG motor driver 410 generates an LF motor drive signal in accordance with a pulse motor control signal (PM control signal) from the ASIC 403, thereby driving the LF motor 411 and generating a PG motor drive signal. The PG motor 412 is driven.
[0042]
A power control circuit 413 controls power supply to each sensor having a light emitting element according to a power control signal from the ASIC 403. The parallel I / F 414 transmits a parallel I / F signal from the ASIC 403 to a parallel I / F cable connected to the outside, and transmits a signal of the parallel I / F cable to the ASIC 403.
[0043]
The ASIC 403 is a one-chip semiconductor integrated circuit, which is controlled by the CPU 401 through a control bus and outputs the above-described CR motor control signal, PM control signal, power control signal, head power ON signal, motor power ON signal, and the like. In addition to transmitting and receiving signals to and from the parallel I / F 414, the state of the PE detection signal from the PE sensor 415, the ASF detection signal from the ASF sensor 416, and the PG detection signal from the PG sensor 417 are detected to indicate the state. The data is transmitted to the CPU 401 through the control of the data, and based on the input data, the CPU 401 controls the driving of the LED driving signal to blink the LED 418.
[0044]
In the recording apparatus described above, the time from the previous recording operation to the current recording operation (elapsed time from the end of the previous recording operation to the start of the current recording operation) is measured, and the measured time is measured. Accordingly, the carriage is caused to perform idle scanning before the printing operation. By this empty scan, the ink in the supply tube 207 and the ink in the sub tank 202 are vibrated and stirred. Therefore, it is possible to alleviate the unevenness of the ink density in the supply tube 207 and in the sub tank 202 of the print head, to prevent a change in the print density, and to improve the discharge characteristics when discharging the ink droplets from the print head. It is possible to keep good.
[0045]
Hereinafter, a specific embodiment will be described in more detail.
[0046]
(1st Embodiment)
FIG. 5 illustrates the operation procedure of the first embodiment.
[0047]
First, when the recording apparatus receives the recording operation start signal in S1, the elapsed time T from the end of the previous recording operation to the start of the current recording operation is measured in S2. Here, the elapsed time T is measured as follows. That is, the CPU 401 in FIG. 4 reads out the end time (latest end time) in the previous recording operation stored in the memory unit (not shown), and subtracts the end time from the current time to obtain the previous recording time. Obtain the elapsed time from the end of operation. Subsequently, in S3, it is determined whether or not the measured time T exceeds a predetermined time T0. If the predetermined time T0 has been exceeded, an empty scan is executed in the next S4. In the present embodiment, the predetermined time T0 is 72 hours, and the number of empty scans is three. After the end of the idle scan, a recording operation based on the image data is executed in the subsequent S5. If the elapsed time T does not exceed the predetermined time T0 in S3, the idle scan is not performed, and the recording operation is performed in S5. In S6, it is determined whether or not the next recording (recording on the next page) is to be performed. If there is no next recording (recording on the next page), the recording operation is terminated in S7. If there is a record (recording on the next page), the recording operation is continued. In S7, in addition to terminating the recording operation, the end time in the current recording operation is stored in a memory unit (not shown). The end of the printing operation in S7 may be (1) the end of ink ejection by the print head based on the image data, or (2) executed after the end of ink ejection by the print head based on the image data. It may also refer to the end of the preliminary ink ejection from the recording head to the recovery means, or (3) the operation of covering the ejection opening surface of the recording head with a cap after the ink ejection by the recording head based on the image data (cap closing). (Operation) may be performed.
[0048]
Further, in the flowchart of FIG. 5, the time when the printing apparatus receives the printing operation start signal is defined as “start of the current printing operation”. However, the present invention is not limited to this. The start of the operation of separating the cap from the ejection port surface (cap open operation) may be referred to as “start of the current recording operation”.
[0049]
As described above, in the present embodiment, the empty scan of the carriage is executed when the elapsed time from the previous printing operation exceeds a predetermined time, that is, when the ink density tends to be uneven. Since the ink density in the supply tube, the print head, and the sub-tank (the sub-tank mounted on the carriage together with the print head) is not uniform, it is possible to alleviate the state before the printing operation. High-quality images can be output. Specifically, even in the case where the elapsed time from the previous printing operation exceeds a predetermined time, in the conventional mode in which the printing operation is performed without performing the idle scan, the inside of the supply tube or the inside of the printing head is not used. The initial operation of the printing operation (between the first scan and several scans) due to the fact that the ink density in the sub tank (the sub tank mounted on the carriage together with the print head) becomes higher than the ink density in the main tank. There is a high possibility that the density of the image formed on the image will be higher than the density of the other portions, resulting in an image having uneven density. In particular, a sub-tank of a recording head normally holds several milliliters of ink, and density unevenness due to non-uniform ink density in this sub-tank is remarkable. On the other hand, when the elapsed time from the previous printing operation exceeds a predetermined time, the empty scan is executed, and then the printing operation is performed. In the present embodiment, the empty scan is performed in the supply tube or the print head (in the sub tank). Of the ink in the supply tube, the print head, the sub-tank (the sub-tank mounted on the carriage together with the print head) and the ink density in the main tank are alleviated. The density of an image formed at the beginning of the operation (between the first scan and several scans) is suppressed from becoming higher than the density of other portions, and a high-quality image with sufficiently reduced density unevenness can be formed. .
[0050]
(Second embodiment)
In the first embodiment, the idle scan is performed if the elapsed time from the end of the previous recording operation exceeds the predetermined time. However, the number of idle scans is set to a constant value regardless of the elapsed time. I was As for the number of empty scans, if emphasis is placed on the mitigation of non-uniformity of the ink density, it is desirable to set a large number of empty scans, but in this case, the recording time becomes longer. On the other hand, if emphasis is placed on shortening the recording time, it is desirable to set the number of blank scans small, but in this case, it may not be possible to reduce the non-uniformity of the ink density.
[0051]
Therefore, in the second embodiment, in order to both reduce the non-uniformity of the ink density and shorten the printing time, the second embodiment is designed to control the elapsed time from the end of the previous printing operation to the start of the current printing operation. The configuration is such that the number of empty scans is made different. That is, the longer the elapsed time from the end of the previous printing operation, the higher the non-uniformity of the ink density is, and the number of scans is increased, while the elapsed time from the end of the previous printing operation is shorter. Accordingly, it is considered that the non-uniformity of the ink density is correspondingly low, and the number of scans is reduced.
[0052]
FIG. 6 illustrates the operation procedure of the second embodiment. Steps S1 to S3 are the same as those in the first embodiment. At S3, in the present embodiment, T1 is set to 168 hours, and if it exceeds 168 hours, the process proceeds to S4, and the empty scan is executed eight times. Thereafter, steps S5 to S7 are the same as those in the first embodiment, and a description thereof will not be repeated. If it does not exceed T1 in S3, the process proceeds to S8, and it is determined whether or not the measurement time T exceeds T2. Here, T2 was set to 72 hours. If it exceeds T2, three empty scans are executed in the subsequent S9, and the process proceeds to S5. If it is determined in S8 that the measured time does not exceed T1, the process proceeds to S5 without executing the blank scan and executes the recording operation.
[0053]
In the present embodiment, it is determined that the longer the unused period is, the more the degree of the loss of the uniformity of the concentration in the tube or the sub-tank is large. A highly reliable recording device is obtained. From the opposite point of view, if the unused period is short, it is considered that the density non-uniformity can be resolved with a small number of blank scans, and if the elapsed time from the end of the previous printing operation is short, the blank scan number is reduced. Since the number is reduced, unnecessary blank scanning is not performed, and the recording time can be reduced.
[0054]
Further, in the present embodiment, two threshold values of T1 and T2 are provided, but the present invention is not limited to this, and an arbitrary number of threshold values (judgment values) can be set.
[0055]
As described above, according to the present embodiment, the number of empty scans is appropriately varied according to the elapsed time from the end of the previous recording operation to the start of the current recording operation. While minimizing the recording time by minimizing it, ensure that the ink concentration in the supply tube, the recording head, and the sub-tank (the sub-tank mounted on the carriage together with the recording head) is uneven. Can be eased.
[0056]
(Third embodiment)
In the present embodiment, the scan speed in the idle scan operation in which the print head scans without discharging the ink from the print head, and the scan speed in the normal scan operation in which the print head scans while discharging the ink from the print head are set as follows. The feature is that scanning operation control is performed so as to positively differ. In other respects, the configuration is the same as that of the first embodiment and the second embodiment, and the description thereof is omitted.
[0057]
As described above, the reason for performing the idle scan is to reduce the non-uniformity of the ink density by vibrating and stirring the ink in the supply tube, the print head, and the sub-tank (the sub-tank mounted on the carriage together with the print head). It is in. If only a lot of ink is vibrated and agitated, it is effective to increase the number of empty scans. However, in this case, the time required for the empty scan is prolonged.
[0058]
Therefore, in the present embodiment, it is an object to provide an empty scan operation in which the ink vibration is large and the ink is easily stirred while shortening the time required for the empty scan as much as possible. I have. Specifically, the scan speed during the blank scan is set higher than the scan speed during the normal scan. In other words, the normal scan involves driving conditions (drive frequency, recording resolution, etc.) due to the ink discharge, but the blank scan does not involve the ink discharge, thereby eliminating the drive condition restrictions. Therefore, the scan speed of the blank scan can be increased to the limit of the device performance, and can be set faster than the scan speed of the normal scan.
[0059]
According to the above configuration, since the idle scan speed is high, the ink vibration can be further increased, and accordingly, the ink is more easily stirred, and the unevenness of the ink density can be further reduced. Further, the time required for the empty scan can be reduced. That is, if the configuration of the third embodiment is applied to the first and second embodiments, the time required for the empty scan is shorter than that of the first and second embodiments. In addition, the non-uniformity of the ink density can be reduced while shortening.
[0060]
In the first and second embodiments, scan operation control is not performed so that the scan speed during the idle scan operation and the scan speed during the normal scan operation are positively different. Therefore, as compared with the present embodiment in which the scan speed in the idle scan operation and the scan speed in the normal scan operation are positively different from each other, the configuration relating to the scan operation control can be advantageously simplified.
[0061]
(Fourth embodiment)
In the first to third embodiments, when the elapsed time from the end of the previous recording operation to the start of the current recording operation is measured by software, the end time (the latest end time) in the previous recording operation is read. The elapsed time is measured by subtracting the end time from the current time. That is, the elapsed time itself is directly measured. However, the present invention is not limited to the configuration in which the elapsed time itself is directly measured, but may be a configuration in which the elapsed time is indirectly acquired. That is, the present invention can be applied to a configuration for acquiring information corresponding to the elapsed time.
[0062]
For example, a counter that counts up by “1” every 100 msec is provided in the printing apparatus. Then, the count-up by the counter is started at the end of the previous recording operation, and the count-up by the counter is ended at the start of the current recording operation, thereby acquiring the count value. The presence / absence of empty scans and the number of empty scans are obtained by referring to the count value thus obtained and a predetermined table (a table in which the range to which the count value belongs and the number of empty scans) is referred to. is there. Specifically, information (counter value) corresponding to the time from the end of the previous recording operation to the start of the current recording operation is acquired, and the blank scan corresponding to the range to which the acquired information (count value) belongs. The number of times is acquired, and the acquired number of empty scans is executed.
[0063]
[Table 1]

[0064]
As described above, in the present invention, the elapsed time from the end of the previous recording operation to the start of the current recording operation may be obtained directly or indirectly. In short, it is only necessary to obtain information corresponding to the time from the end of the previous recording operation to the start of the current recording operation. In this case, the information corresponding to the time from the end of the previous recording operation to the start of the current recording operation is obtained. The information may be acquired, and whether or not the empty scan is performed and the number of times of the empty scan may be determined according to the acquired information.
[0065]
(Other embodiments)
Embodiments 1 and 2 can be further developed to combine an ink tank stirring means. As a stirring means of the ink tank, the flow of the ink may be generated by operating a valve provided in the tube as in the conventional example described above, or a stirring mechanism such as a wing may be provided in the tank. . In this case, the idle scan and the stirring may be performed in accordance with the time interval from the previous recording operation, or may be performed in combination according to the length of the time interval.
[0066]
In the present embodiment, an ink jet recording apparatus having a flow path such as a tube has been described. Needless to say.
[0067]
【The invention's effect】
As described above, according to the present invention, since the idle scan is performed based on the information corresponding to the elapsed time from the previous printing operation, the ink concentrations in the supply tube and the printing head become uneven. Since the state can be alleviated before the printing operation, it is possible to output a high-quality image and to prevent deterioration of ejection characteristics due to high-density ink.
[0068]
In addition, since the number of times of performing the empty scan is changed according to the time interval, more effective and reliable recovery of the ejection characteristics can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an ink jet recording apparatus according to the present invention.
FIG. 2 is a schematic diagram of an ink supply system in the inkjet recording apparatus of FIG.
FIG. 3 is a schematic diagram of an overall configuration of an electric circuit in the inkjet recording apparatus of FIG.
FIG. 4 is a schematic control block diagram of the inkjet recording apparatus of FIG. 1;
FIG. 5
FIG. 3 is a diagram illustrating a recording operation according to the first embodiment.
FIG. 6
FIG. 11 is a diagram illustrating a recording operation according to the second embodiment.
FIG. 7
FIG. 2 is a schematic diagram of an ink jet recording apparatus in which a recording head and an ink tank are connected by a tube.
[Explanation of symbols]
1 Recording head
2 carriage
3 Supply tube
4 Atmosphere communication tube
5 Ink tank
12 Carriage motor
13 Flexible cable
14 means of recovery
15 Paper tray
16 Optical position sensor
21 cap
22 Discharge tray
23 Wiper blade
201 Main tank
202 Sub tank
203 buffer room
207 tubes
208 Joint
301 carriage board
302 Main PCB
303 power supply unit
304 Contact FPC
305 Encoder sensor
306 Encoder scale
308 Paper edge detection sensor (PE sensor)
309 ASF sensor
310 cover sensor
311 Parallel interface (parallel I / F)
312 Resume key
313 LED
314 Power key
315 Buzzer
316 CR motor
317 LF motor
318 PG motor
319 PG sensor

Claims (13)

In an inkjet recording apparatus that performs recording using a recording head for discharging ink,
Scanning means for causing the recording head to scan a recording medium,
Measuring means for measuring the time from the end of the previous recording operation to the start of the current recording operation,
Determining means for determining whether the measurement result by the measuring means has exceeded a predetermined time,
With
The inkjet recording apparatus according to claim 1, wherein the scanning unit causes the recording head to perform idle scanning before starting a recording operation in accordance with a result of the determination by the determination unit. As the predetermined time used at the time of the determination by the determination means, a plurality of different predetermined time is provided,
The apparatus according to claim 1, wherein the determination unit performs the determination in a plurality of stages according to the plurality of different predetermined times. 3. The ink jet recording apparatus according to claim 1, wherein the scanning unit changes the number of times of the blank scan according to a length of time measured by the measuring unit. 4. The inkjet recording according to claim 3, wherein the scanning unit increases the number of times of the empty scan when the length of time measured by the measuring unit is relatively long, as compared with a case where the time is relatively short. apparatus. 5. The ink jet recording apparatus according to claim 1, wherein the ink is a pigment ink. An ink tank for storing the ink,
6. The ink jet recording apparatus according to claim 1, wherein the recording head and the ink tank are connected via a tube flow path for supplying the ink. The ink jet recording apparatus according to claim 6, wherein the ink tank includes a stirring unit that stirs the ink in the empty scan and the ink therein. The inkjet recording apparatus according to claim 1, wherein the scanning unit performs an idle scan at a speed higher than a scan speed of a normal scan that scans the print head while discharging ink. In an inkjet recording apparatus that performs recording using a recording head for discharging ink,
Scanning means for causing the recording head to scan a recording medium,
Acquisition means for acquiring information corresponding to the time from the end of the previous recording operation to the start of the current recording operation,
Determining means for determining whether or not to cause the print head to perform idle scan before starting a printing operation, according to the information obtained by the obtaining means;
An ink jet recording apparatus comprising: In an inkjet recording apparatus that performs recording using a recording head for discharging ink,
Scanning means for causing the recording head to scan a recording medium,
Acquisition means for acquiring information corresponding to the time from the end of the previous recording operation to the start of the current recording operation,
Determining means for determining the number of empty scans to be performed before the start of a printing operation, according to the information obtained by the obtaining means;
An ink jet recording apparatus comprising: In an ink jet recording method for performing recording using a recording head that discharges ink,
A scanning step of causing the recording head to scan the recording medium,
A measuring step for measuring a time from the end of the previous recording operation to the start of the current recording operation,
A determination step of determining whether or not the measurement result by the measurement step has exceeded a predetermined time;
With
The inkjet recording method according to claim 1, wherein the scanning step includes a step of causing the recording head to perform an idle scan before a recording operation is started, according to a result of the determination. In an inkjet recording method for performing recording using a recording head for discharging ink,
A scanning step of causing the recording head to scan the recording medium,
An acquisition step of acquiring information corresponding to a time from the end of the previous recording operation to the start of the current recording operation,
A determining step of determining whether to cause the print head to perform idle scan before starting a printing operation, according to the information obtained in the obtaining step;
An ink jet recording method comprising: In an inkjet recording method for performing recording using a recording head for discharging ink,
A scanning step of causing the recording head to scan the recording medium,
An acquisition step of acquiring information corresponding to a time from the end of the previous recording operation to the start of the current recording operation,
A determining step of determining the number of empty scans to be performed before the start of a printing operation, according to the information acquired in the acquiring step;
An ink jet recording method comprising:

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