JPH07214792A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent waste consumption of ink and ejection failure thereof by a method wherein the numbers of times of the preliminary ejection for recovering a clogging are varied in accordance with kinds of inks. CONSTITUTION:After an ink jet head is preliminary heated by an electric signal by which ink is not ejected up to a specific temperature by which the ejection may be stable (S2), the ink is preliminary ejected in accordance with an electric signal of which frequency is lower than that in the recording so that the ejection failure of the ink after a long interval of non-recording is prevented. At that time, in the case where, for example, a plurality of colors of inks such as black, cyan, magenta and yellow are used in the color printing, the numbers of times of preliminary ejection are different with each other by setting them corresponding to the colors, that is, a record head of black ink corresponds to Nk times (S4), cyan to Nc times (S6), magenta to Nm times (S8) and yellow to Ny times (S10). Thus, the numbers of times of preliminary ejection correspond to the respective colors so that it is possible to recover the clogging without operating unnecessary number of times of the preliminary ejection in the case of the inks of cyan, magenta and yellow each having non-drying property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pre-driving an ink jet recording apparatus for recording by ejecting ink liquid from a recording head onto a recording medium.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, the tip of a nozzle for ejecting a recording liquid is constantly open to the outside air regardless of whether or not the apparatus is driven. In particular, when the operating environment temperature of the recording apparatus is low, the viscosity of the recording liquid increases, and the ejection nozzles are easily clogged. Immediately after restarting recording, the ejection signal is applied. Nevertheless, there is a problem that defective ejection of droplets is likely to occur and a defect occurs in initial printing of a recorded image. In addition,
When the recording device is not used, a method of covering the ejection surface provided with the nozzle with a cap is also used, but since the nozzle is not completely shielded from the outside air, it is essential to solve the above problem. I won't.

Conventionally, in order to solve the above problems, the drive pulse period and drive pulse width of the head are set by converting them into clock periods in order to optimize the printing state quickly and easily. A method for pre-driving a recording head by setting the number of drive pulses is disclosed in Japanese Patent Laid-Open No.
It is described in JP-A-2-179945. Japanese Patent Laid-Open No. 3-155952 discloses a method of calculating the immediately preceding recorded image information and setting the number of idle discharges of the energy generator in order to slightly change the idle discharge amount or to suppress it as much as possible. .

[0004]

However, when there is a difference in the type of ink in color printing such as ink that is easy to dry and ink that is difficult to dry, when the state in which recording is not performed for a long time continues. Such as
There is a difference in the increase in the viscosity of the ink due to the evaporation of the volatile solvent of the ink. Since the increase in the viscosity of the ink causes defective ejection, the preliminary ejection operation described above may be performed on the recording head before the printing operation.
Unnecessary for ink that does not easily increase in ink viscosity and that does not increase in viscosity if the same number of preliminary ejections are performed for all recording heads based on the ink head that is easy to dry, that is, the one that has a large increase in ink viscosity. Ink will be ejected. On the contrary, if the same number of preliminary ejections are performed on all the recording heads based on the recording heads of the ink that is difficult to dry, the ejection failure of the inks is likely to occur in the inks that easily increase in the viscosity of the ink and tend to dry. There was such a problem.

The present invention is intended to solve the above problems, and in color printing having a plurality of colors of ink, the number of preliminary ejection operations for recovering clogging is made different for each ink. Accordingly, it is an object of the present invention to provide an inkjet recording apparatus capable of preventing wasteful consumption of ink and preventing defective ejection of ink.

[0006]

To this end, an ink jet recording apparatus of the present invention has a plurality of color inks, and in an ink jet recording apparatus for performing color print recording, each ink is used for recovery from clogging. It is characterized in that the number of preliminary ejection operations is different.

[0007]

In the present invention, when the recording is not performed for a long time, the volatile solvent of the ink accumulated in the ejection port and its vicinity evaporates even if the recording head is in a standby state, and the ink viscosity is increased. Therefore, the ejection failure is likely to occur in the next printing operation. So, for example, black ink is the easiest to dry,
In the case where cyan, magenta, and yellow are less likely to dry in this order, it is possible to recover from clogging with cyan, magenta, and yellow inks that are difficult to dry without performing unnecessary preliminary ejection.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a system configuration diagram showing an embodiment of an ink jet recording apparatus of the present invention, FIG. 2 is a schematic configuration diagram of a carriage periphery in an embodiment of the ink jet recording apparatus of the present invention, and FIG. 3 is an ink of the present invention. 7 is a flowchart for setting the number of preliminary ejection operations by.

In FIG. 1, 1 is an ink jet recording apparatus, 2 is a host computer, 3 is a CPU, 4 is a work RAM, 5 is a font ROM, 6 is a program ROM,
7 is an EEPROM, 8 is an interface, 9 is an operation panel, 10 is a memory controller, and 11 is an image RA.
M, 12 are head controllers, 13 are recording heads, 1
4 is a motor controller, 15 is a motor, 16 is an I / O
A controller, 17 is a sensor, and 18 is a common bus.

The ink jet recording apparatus 1 is connected to the host computer 2 and exchanges data between them. CPU3 is work RAM4, font ROM5,
It is connected to the program ROM 6 and the EEPROM 7, and according to the program stored in the program ROM 6, set values stored in the EEPROM 7, for example,
It operates while referring to correction data and the like for high image quality. The CPU 3 is also connected to the common bus 18, and controls each unit in the inkjet recording apparatus 1 through the common bus 18.

The work RAM 4 is used as a work storage area of the CPU 3, and is also used to store information and the like in various systems. The font ROM 5 stores image format data of characters to be printed. The program ROM 6 stores a program for instructing the operation of the CPU 3. Since the EEPROM 7 is a non-volatile memory and retains its contents even when the power is cut off, it stores correction data for improving image quality, various set values such as a system operation mode, and the like. These data may be set using the operation panel 9.

The interface 8 is connected to the common bus 18 and the host computer 2, and the host computer 2
Send and receive data directly with. The operation panel 9 is connected to the common bus 18, receives various inputs from the user, and displays various states and messages to the user.

The memory controller 10 uses the image RA
It is connected to the M11, the common bus 18, and the head controller 12, and controls the image RAM 11. Image RA
Data to be recorded is stored in M11 in the form of an image. The image RAM 11 can be divided into areas corresponding to the recording heads.

The head controller 12 is the recording head 1.
3, connected to the common bus 18 and the memory controller 10 to control the recording head 13. The control of the recording head 13 includes at least control of ink ejection timing from each nozzle of each recording head, ink temperature, and the like. Further, a part of the control of the CPU 3, such as the control of the used nozzle based on the nozzle selection information as described later, may be performed instead.

The recording head 13 is composed of a plurality of heads having N nozzles. For example, in the case of color printing, it is composed of four recording heads of black (K), cyan (C), magenta (M) and yellow (Y).

The motor controller 14 includes a motor 15
And is connected to the common bus 18 to control the motor 15. The motor 15 relatively moves the carriage on which the recording head 13 is placed and a recording medium, for example, recording paper. The I / O controller 16 is connected to the various sensors 17 and the common bus 18, and controls the various sensors 17 and acquires sensor data. The sensor 17 is, for example, a sensor for detecting the edge of the paper, detecting the width of the paper, detecting the amount of ink, or the like.

The common bus 18 includes a CPU 3, an interface 8, an operation panel 9, a memory controller 10, a head controller 12, a motor controller 14 and I.
It is connected to the / O controller 16 and transmits various data and control signals. Although the above-mentioned configurations are functionally separated, the image RAM 11 and the work RA
Modifications such as using the same RAM for M4 are also possible.

The operation of the system shown in FIG. 1 will be described. CPU
3 operates in accordance with the program stored in the program ROM 6 while referring to the set values and the like stored in the EEPROM 7. At that time, the work RAM 4 is used if necessary. The setting values and the like stored in the EEPROM 7 are set using the operation panel 9. Also, C
The PU 3 is connected to the sensor 17 via the I / O controller 16.
The information on the print position is checked to determine whether printing is possible, the motor controller 14 is instructed to move the carriage, convey the recording paper, and the like, and the printing position is adjusted.

When data to be recorded, such as image information or character code, is sent from the host computer 2, the interface 8 receives the information and transfers the received data to the work RAM 4. The CPU 3 converts the received data into image data capable of recording, for example, a bitmap according to the print format. For example, if the received data is a character code, it is converted into image data of the character using the font ROM 5. The converted image data is stored in the image RAM 11 via the memory controller 10.

At this time, if the head temperature is low immediately before printing, the ink ejection characteristics are adversely affected. Therefore, the power supply to the power supply is determined based on the temperatures detected by the temperature detecting elements incorporated in the printer body and each head. The head drive pulse width and drive frequency are determined according to the system configuration from the burden and cost increase, and the head drive pulse width and drive frequency are sent to the head controller 12 and the head is heated to a predetermined temperature at which the ink ejection characteristics are stable.

Next, the CPU 3 controls the motor controller 14
The carriage is requested to be moved and scanning is performed. An encoder for generating print timing is attached to the carriage on which the recording head 13 is mounted, and the print timing according to the scanning speed of the carriage is input to the CPU 3 and the head controller 12. The CPU 3 determines the print start position at this timing and supplies a print enable gate signal to the head controller 12. The head controller 12 outputs a head drive signal to the recording head 13 in response to the print permission gate signal and the print timing signal. When this operation is continuously performed and printing for one scan is completed, an interrupt is generated from the memory controller 10 and the interrupt is input to the CPU 3. Receiving this interrupt signal, the CPU 3 requests the motor controller 14 to convey the recording medium of the print recording width and rescan the carriage. In this way, printing for one scan is performed a plurality of times until the print recording operation in the transport direction of the recording medium is completed.

When the printing operation on one recording medium is completed in this way, the CPU 3 causes the motor controller 14 to operate.
The recording medium is discharged, the carriage is moved to the position of the cap member that covers the nozzle portion to prevent the ink from drying, the cap operation is performed, and the printer waits until the next printing operation. . The printing operation on one recording medium is completed by the above series of operations.

Here, in the case where recording is not performed for a long time, the volatile solvent of the ink that has accumulated in the ejection port and its vicinity evaporates even when the recording head is in the capped state, and the viscosity of the ink increases. Therefore, ejection failure is likely to occur when the printing operation is performed next time. Therefore, as shown in the flow chart of FIG. 3, the temperature of the recording head is detected before the printing operation, and as described above, it is preliminarily heated to a predetermined temperature at which the ink ejection characteristics are stabilized by an electric signal that does not eject ink. After that, the ink is preliminarily ejected by an electric signal having a frequency lower than that at the time of recording, thereby preventing the ejection failure of the ink after the recording is not performed for a long time. In this case, for example, ink color printing, black, cyan, magenta, when there are a plurality colors as such yellow, N _K times the number of preliminary ejection with respect to the black ink recording head for the cyan recording head Is N
_C times, N _M times for the magenta ink recording head,
It is set to N _Y times for the yellow recording head. Here, for example, in the case where the black ink is the ink that dries the most, and it becomes difficult to dry in the order of cyan, magenta, and yellow, the set number of preliminary ejections is N _K > N.
_C > N _M > N _Y. As described above, by varying the number of preliminary ejections for each ink color, it is possible to recover from clogging with cyan, magenta, and yellow inks that are difficult to dry without performing unnecessary preliminary ejections.

The number of times of preliminary ejection is set when the position of the recording head for each ink color is determined.
Whether to set the number of idle discharges for each position,
Alternatively, identification information or the like may be put in the recording heads, and the number of idle ejections of each recording head may be selected and set according to the information. In this way, when the number of times of preliminary ink ejection is set in the head controller 12, the operation of preliminarily ejecting the recording head is performed.

FIG. 2 is a schematic configuration diagram of the periphery of the carriage in one embodiment of the ink jet recording apparatus of the present invention. In the figure, 19 is a recording head unit, 20 is a carriage, 21 is a recording medium, and 22 is a transport roller. One or a plurality of recording head units 19 are mounted on the carriage 20. Each of the recording head units 19 or a plurality of recording head units 19 are integrally configured to be attachable to and detachable from the carriage 20. Further, the recording head unit 19 is provided with a plurality of nozzles. While scanning the carriage 20 left and right, ink is ejected from the nozzles to perform printing. This printing is performed by using a plurality of recording head units 1 on the carriage 20.
9 is mounted, each recording head unit 19
The ink is ejected from the ink, and the dots of the ink are overlapped to form an image. A color image can be formed by using, for example, four recording heads of black, cyan, magenta, and yellow as the plurality of recording head units 19. Carriage 2
When one scan operation of 0 is completed, the transport roller 22 conveys the recording medium 21 by a predetermined amount. This operation is repeated to finish printing on one recording sheet.

In this embodiment, the movement of the recording medium in the vertical direction is performed on the side of the recording medium, but it is also possible to move the carriage 20. In addition, this movement amount is performed only for one print width or a predetermined line feed width,
You can also send a blank scan only. Further, for example, when the recording medium is fed or when the recording medium is positioned when recording according to a predetermined format, the recording medium can be moved in accordance with an instruction from the CPU 3, and an instruction from the host computer 2 can be given. It is also possible to change the movement amount by.

[0027]

As described above, according to the present invention, the number of preliminary ejection operations for recovering the clogging is made different for each of the inks of a plurality of colors, so that the inks which are hard to dry can be obtained. It is possible to prevent unnecessary ejection, minimize ink consumption in the clogging recovery operation, and prevent defective ejection of ink.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an inkjet recording apparatus of the present invention.

FIG. 2 is a schematic configuration diagram around a carriage in an embodiment of the inkjet recording apparatus of the present invention.

FIG. 3 is a flowchart for setting the number of preliminary ejection operations with ink according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink jet recording device, 2 ... Host computer, 3 ... CPU 4 ... Work RAM, 5 ... Font ROM, 6 ... Program ROM 7 ... EEPROM, 8 ... Interface, 9 Operation panel 10 ... Memory controller, 11 ... Image RAM 12 ... Head controller, 13 ... Recording head, 14 ...
Motor controller 15 ... Motor, 16 ... I / O controller, 17 ... Sensor, 18 ... Common bus 19 ... Recording head unit, 20 ... Carriage, 21 ...
Recording medium 22 ... Transport roller

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Claims (1)

[Claims] 1. An inkjet recording apparatus having a plurality of color inks for performing color print recording, wherein the number of preliminary ejection operations for recovering clogging is made different for each ink. Inkjet recording device.