JPH09201984A - Inkjet printer - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To manage the time for performing a maintenance operation for each print head to eliminate wasteful consumption of ink. In step 131, a black head 22
The timer Ta that counts the elapsed time of B. F. If it reaches, the preliminary ejection of the black head 22 is performed in step 132, and the timer Ta is reset in step 133. These steps are step 134
Through heads of different colors 23 to 2 as shown in FIG.
By carrying out also for No. 5, preliminary ejection is performed at a time corresponding to the head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printer that prints by ejecting ink onto a printing medium.

[0002]

2. Description of the Related Art Conventionally, in an ink jet printer (hereinafter abbreviated as a printer) which ejects ink onto a print medium to perform printing, in order to maintain a good ink ejection state, flushing, purging, etc. Maintenance operation is being performed. In order to prevent the nozzles of an inkjet head (hereinafter abbreviated as “head”) from running dry, flushing is performed by periodically moving the head to a position where an ink absorber is provided, and removing all ink from the ink absorber. It is an operation to eject ink from all nozzles of the head,
Purging is to move the head to a position where a suction mechanism is provided in order to remove air bubbles in the nozzles, and the suction mechanism causes the ink containing air bubbles from all nozzles of all the heads to be removed. This is an operation of sucking and discarding.
In addition, there are maintenance operations such as capping for covering the nozzle when printing is not used for a certain period of time or wiping for wiping the ejection surface of the nozzle.

[0003]

By the way, the properties such as the drying speed and the viscosity are different depending on the ink. In particular, in a color printer that performs color printing by ejecting a plurality of colors of ink, the usage amount also differs depending on the ink. Therefore,
When flushing or purging is performed like the above-mentioned conventional one, if ink is ejected to all nozzles of all heads or ink is sucked, originally,
Even the ink on the head that does not require maintenance is discarded. That is, the above-mentioned conventional one has a problem that ink is wasted.

Therefore, the present invention has been made to solve the above-mentioned problems, and the purpose thereof is to manage the time for performing the maintenance operation for each head to eliminate wasteful consumption of ink. To do.

[0005]

In order to achieve the above object, the present invention provides a printing method by ejecting different inks from nozzles provided in an ink chamber onto a printing medium in the invention described in claim 1. In an inkjet printer that is provided with a plurality of print heads to perform, and the maintenance means for improving the ink discharge state of each print head, the maintenance means is a predetermined one set for each print head. A technical means is adopted in which a predetermined maintenance operation is executed for each of the print heads on the basis of time to improve the ink ejection state of each print head.

According to a second aspect of the present invention, in the ink jet printer according to the first aspect, there is provided technical means that the predetermined maintenance operation is to eject a predetermined amount of ink from the nozzle of the print head. adopt.

According to a third aspect of the present invention, in the ink jet printer according to the first aspect, there is provided technical means that the predetermined maintenance operation is to suck a predetermined amount of ink in the ink chamber of the print head. adopt.

According to a fourth aspect of the present invention, in the ink jet printer according to any one of the first to third aspects, the predetermined time is set based on a property of ink ejected from each print head. The technical means of being adopted is adopted.

According to a fifth aspect of the present invention, in the ink jet printer according to any one of the first to fourth aspects, the maintenance means includes a time period from a time when the last maintenance operation is performed to a current time. A technical means is adopted in which maintenance operation execution means is provided for executing the maintenance operation when the elapsed time reaches the predetermined time.

According to a sixth aspect of the present invention, in the ink jet printer according to any one of the first to fifth aspects, each of the print heads ejects ink of a different color. To adopt.

[0011]

According to the invention described in claims 1 to 6, the maintenance means executes a predetermined maintenance operation for each print head based on a predetermined time set for each print head to perform each printing. Since the ink ejection state of the head can be improved, maintenance management can be performed for each print head. For example, as described in an embodiment of the invention described below, wasteful consumption of ink can be eliminated by managing the maintenance cycle for each color of ink.

According to the second aspect of the invention, since the predetermined maintenance operation is to eject a predetermined amount of ink from the nozzles of the print head, the ink from the nozzles is wasted for each print head. Discharge can be prevented.

According to the third aspect of the invention, since the predetermined maintenance operation is to suck a predetermined amount of ink in the ink chamber of the print head, the ink from the nozzle is wasted for each print head. Suction can be prevented.

In the invention according to the fourth aspect, the predetermined time can be set based on the property of the ink ejected from each of the print heads. Therefore, the maintenance cycle corresponding to the property of the ink is set. By setting, it is possible to prevent wasteful consumption of ink according to the property of the ink.

According to a fifth aspect of the present invention, the maintenance means performs the maintenance operation when the elapsed time from the time when the last maintenance operation is executed to the current time reaches the predetermined time. Since the maintenance operation executing means for executing the maintenance operation is provided, it is possible to surely execute the maintenance operation when it is time to perform the maintenance operation. In other words, unnecessary maintenance operations are not executed during times other than the maintenance operations, so that wasteful consumption of ink can be prevented.

According to the sixth aspect of the present invention, since each of the print heads ejects ink of a different color, it is possible to manage the maintenance cycle for each color of ink. That is, it is possible to prevent wasteful consumption of ink for each color of ink.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing the main structure of the printer of the present invention, and FIG. 2 is a block diagram showing its control system.

As shown in FIG. 1, the printer 10 is provided with a platen 12 into which printing paper, which is a printing medium, is loaded. The platen 12 is connected to an LF motor (paper feed motor) 58. It is rotated by the paper feeding mechanism 62 (see FIG. 2). At the position facing the platen 12,
A head (printing head) 20 is provided, and the head 20 is mounted on a carriage 21. A guide shaft 14 mounted in the width direction of the printer 10 is inserted through a lower front portion of the carriage 21, and a lower rear portion is slidably supported on a rail 16. Further, the carriage 21 is connected to an endless belt 30 which is wound around a CR motor (carriage moving motor) 18. That is, the head 20 causes the platen 12 to move over the guide shaft 14 and the rail 16 by the rotation of the CR motor 18.
Reciprocates opposite to. A step motor is used for the LF motor 58, and a DC motor whose rotation speed is controlled by PWM control is used for the CR motor 18.

To the head 20, a black head 22 for ejecting black ink, a yellow head 23 for ejecting yellow ink, a cyan head 24 for ejecting cyan ink, and a magenta ink are ejected. And a magenta head 25. Ink is stored in each head, and an ink chamber (not shown) in which nozzles are formed is provided in each head.
By applying a voltage to the piezoelectric element attached to the ink chamber to change the volume of the ink chamber, the ink in the ink chamber is pressurized and the ink is ejected from the nozzle toward the printing paper to perform printing. . Each head is provided with a removable ink cartridge.

Below the guide shaft 14, there is provided a linear timing slit (not shown) in which 90 slits are marked in one inch. A sensor element (not shown) that reads the interval of the slits marked on the timing slits and outputs a pulse signal corresponding to the position of the carriage 21 is provided. The timing slit and the sensor element form a linear encoder 55 (see FIG. 2).

At the left end of the head 20 in the moving direction, an ink absorber 3 for absorbing ink ejected from the nozzles when the head flushes at a position outside the printing area.
2 is provided, and on the right side in the moving direction of the head 20,
A suction cap 34 is provided to cover the head for purging. A purging mechanism 35 is connected to the suction cap 34. This purging mechanism 35
Is provided with a pump 38 connected to the suction cap 34, and the pump 38 has a switching mechanism 61 (see FIG. 2).
Drive) via the LF motor 58.

On the right side of the suction cap 34, there is provided a cap 36 for covering each head when the head is not used for a certain period of time or more. When the cap is moved to the capping position, the nozzle surface of the head 20 is moved in the opposite direction to perform capping.

Next, the main structure of the control system of the printer will be described with reference to FIG. The printer 10 includes a CPU 50 that performs various types of arithmetic processing described below. The CPU 50 has an interface 52 for receiving a signal such as print data output from the host computer 51, a flushing time and a purging time set for each of the heads 22 to 25, and a program used for the arithmetic processing. The ROM 53 and the RAM 54, which store the above information, are respectively connected. Further, the CPU 50 has a timer 6 for counting the time for flushing and purging for each head.
7 is connected. In addition, the timer 67 is the CPU 50
It may be a model built in the.

The CPU 50 is the host computer 5
In order to store the print data received from 1 through the interface 52 in a predetermined area of the RAM 54 and to drive the LF motor 58, the CR motor 18, and the head 20 according to the print program stored in the ROM 53 in advance. It outputs various control signals of. Then, of the control signals, the LF motor drive control signal for driving the LF motor 58 is input to the LF drive circuit 57, and the LF motor 58 is driven according to the LF motor drive signal output from the LF drive circuit 57. To be done. That is, by driving the LF motor 58, the printing paper is fed in the vertical direction.

Of the above control signals, the CR motor 1
The CR motor drive control signal for driving 8 is input to the CR drive circuit 59, and the CR motor 18 is driven according to the CR motor drive signal output from the CR drive circuit 59. The carriage 21 is reciprocated by driving the CR motor 18, and the position of the carriage 21 is detected by the encoder 55. Then, the pulse signal output from the encoder 55 is transmitted to the gate array 5
6, the edge of the pulse signal is detected, the print timing pulse is generated, and the like, as will be described later.

Of the control signals output from the CPU 50, the head drive control signal for driving the head 20 created based on the print data is the head drive circuit 60.
The head 20 is driven in accordance with the head drive signal input to the head drive circuit 60 and output from the head drive circuit 60. That is, when the head drive signal is input to the head 20,
A voltage is applied to the piezoelectric element forming each element of each head, the diaphragm of the cavity provided with the piezoelectric element is displaced, and the ink in the cavity is pressurized and ejected from the nozzle.

Further, the CPU 50 counts the pulse signal which is the drive signal of the LF motor 58, and the LF motor 5
8 and the paper feed mechanism 62 count the feed amount of the printing paper, the rotation amount of the cam driving the purging mechanism 35, and the like. Further, an HP (home position) sensor 63 that detects that the carriage 21 has returned to the origin is provided in the purging mechanism 35, and a PE (paper empty) sensor that detects insertion of printing paper is provided in the paper feeding mechanism 62. 64 are provided respectively.

Now, the gate array 56 will be described with reference to FIG. FIG. 3 is a block diagram illustrating the gate array 56 in the control system shown in FIG. As shown in FIG. 3, the gate array 56 includes an encoder 55.
Based on the edge detection circuit 65 that detects the edge (rising edge) of the encoder signal generated from the sensor element and that generates the reference pulse at the detection timing, and the reference pulse output from the edge detection circuit 65,
A print timing generation circuit 6 that generates speed data calculated from the pulse period (edge interval of the encoder signal) and a print timing pulse for driving the head 20.
6 is comprised.

Then, the CPU 50 inputs the speed data (the time interval value between each edge of the encoder signal) output from the print timing generation circuit 66, and receives the PWM signal (the drive of the CR motor 18) necessary for the speed control of the carriage. The pulse width of the signal) is calculated. Further, the CPU 50 inputs the position control pulse (reference pulse) output from the edge detection circuit 41 and calculates the current position of the carriage. Further, the CPU 50 outputs data such as a delay count value for matching the print positions and permission of the print start signal when the print direction is reversed, to the gate array 5.
Control operations such as writing to the register in 6 are performed.

Next, control for executing flushing and purging processing by the CPU 50 based on time (cycle) management will be described with reference to FIGS. 4 to 7. 4 and 5 are main flowcharts showing main control contents for the above processing. FIG. 6 is a process for performing flushing (hereinafter referred to as preliminary ejection process), and FIG. 7 is a process for performing purging (hereinafter referred to as suction process).
3 is a flowchart showing each of the above.

First, as shown in FIG. 4, in step 100, initialization of a timer for counting the flushing and purging cycle of each head is performed. Here, the black head 22, the yellow head 23, and the magenta head 2 stored in the ROM 53 in advance.
4, the flashing time (cycle) of the cyan head 25 is set to B.E. F. , Y. F. , M .; F. , C.I.
F. And timers for counting those elapsed times are Ta, Tb, Tc, and Td, respectively. Further, the time (cycle) for purging each head 22 to 25 is set to B. P. , Y. P. , M .; P. , C.I. P. And a timer for counting the elapsed time is Te,
Tf, Tg, and Th. These timers Ta to Th
Are provided in the timer 67 so as to independently perform the timer operation.

The time (cycle) for flushing and purging of each head is set to the most optimum value according to the properties such as the drying speed and the viscosity which are different for each color ink. Black, yellow,
The most suitable flushing times (cycles) for magenta and cyan inks are 10 seconds, 15 seconds, and 20 seconds, respectively.
If the second is 20 seconds, the B. F. As "10
Seconds ", Y. F. "15 seconds" as M. F. As "2
0 seconds ", C.I. F. Each value of "20 seconds" is set as
Further, assuming that the optimum purging times (cycles) for the black, yellow, magenta, and cyan inks are 10 days, 15 days, 20 days, and 15 days, respectively.
B. P. As “10th”, Y. P. As "15
Sun ", M.I. P. As "20th", C.I. P. As "1
Each value of "5 days" is set. Of course, each of these values should be appropriately changed according to the properties of the ink used, or should be modified appropriately according to the environment in which the ink is used, and these values are not specified in any way.

Next, control for performing preliminary discharge (flushing) based on time management will be described. First, the preliminary ejection of all the four heads 22 to 25 is executed, and the elapsed time T is set by the timer 67.
Counting of a to Th is started (step 11).
0). Subsequently, when it is determined that the print command is output from the host computer 51 (step 120), the preliminary ejection process shown in FIG. 6 is executed. Step 131 of FIG.
As shown in FIG. 7, the timer Ta counting the flushing cycle of the black head 22 has a preset time B. F. It is determined whether or not the number of ink reaches the ink absorber 3 when it is determined.
After being moved to the flushing position facing 2,
A preliminary ejection command is issued to the black head 22 to perform preliminary ejection (step 132), and the timer Ta is reset (step 133).

On the other hand, when it is determined in step 131 that the time for performing the preliminary ejection of the black head 22 has not been reached, the process proceeds to step 134 and the timer for performing the preliminary ejection of the next yellow head 23 is performed. Tb is set to a preset time Y.T. F. If it is determined that it has reached, after the head 20 is moved to the flushing position, the yellow head 2
A pre-ejection command is issued to No. 3, pre-ejection is performed (step 135), and the timer Tb is reset (step 1).
36).

When it is determined in step 134 that the time for performing the preliminary ejection of the yellow head 23 has not been reached, the process proceeds to step 137, and the timer Tc for flushing the next magenta head 24 is used.
For a preset time M. F. If it is determined that it has reached, after the head 20 is moved to the flushing position, a preliminary ejection command is issued to the magenta head 24 to perform preliminary ejection. (Step 138), the timer Tc is reset (step 139).

On the other hand, when it is determined in step 137 that the time for performing the preliminary ejection of the magenta head 24 has not been reached, the process proceeds to step 140, and the timer for performing the preliminary ejection of the next cyan head 25 is performed. Td is a preset time C.T. F. If it is determined that it has reached, after the head 20 is moved to the flushing position, the cyan head 25
A preliminary discharge command is issued to perform preliminary discharge (step 141). Then, the timer Td is reset (step 142), and the preliminary ejection process 130 ends. In this way, since it is possible to manage the time for performing preliminary ejection for each head, it is possible to prevent ink from being wasted.

Then, returning to step 150 shown in FIG. 4, printing is executed based on the print data output from the host computer 51. In this way, the preliminary ejection process (step 130) and printing (step 1) are performed.
Step 50) is repeated until it is determined in the next step 160 that printing has ended, and when printing has ended, capping is executed (step 170). Then, the process returns to step 120, and if there is no next print command, the process proceeds to step 180 and it is determined whether or not the head replacement is performed.

If the head has not been replaced, the process proceeds to step 210 shown in FIG. 5 and it is determined whether the ink cartridge of any of the heads has been replaced. If none of the cartridges has been replaced, the process proceeds to the suction process in step 240 and the suction process shown in FIG. 7 is executed.

Next, control for performing suction (purging) based on time management will be described. First, as shown in step 241 in FIG. 7, the timer Te counting the purging cycle of the black head 22 is set to a preset time B. P. It has been determined whether or not the black head 2 has been reached.
A series of control commands necessary for the second suction is issued to perform the suction (step 242), and the timer Te is reset (step 243).

On the other hand, when it is determined in step 241 that the time for sucking the black head 22 has not been reached, the process proceeds to step 244, and the purging cycle of the next yellow head 23 is counted. Timer Tf is set to a preset time Y. P. If it is determined that the yellow head 23 has been reached, a series of control commands necessary for the suction of the yellow head 23 are issued and suction is performed (step 245), and the timer Tf is set. Are reset (step 246).

If it is determined in step 244 that the time for sucking the yellow head 23 has not been reached, the process proceeds to step 247 to count the purging cycle of the next magenta head 24. Timer Tg is set to a preset time M. P. If it is determined that it has reached, a series of control commands necessary for suction of the magenta head 24 is issued and suction is performed (step 248), and the timer Tg Are reset (step 249).

On the other hand, if it is determined in step 247 that the time for sucking the magenta head 24 has not been reached, the process proceeds to step 250 and the purging cycle of the next cyan head 25 is counted. Timer Th is set to a preset time C. P. Is determined, and if it is determined that it has reached, a series of control commands necessary for suction of the cyan head 25 is issued and suction is performed (step 251). Then, timer T
h is reset (step 252), and suction processing 240
To end.

If it is determined in step 180 shown in FIG. 4 that the heads have been replaced, all the four heads 22 to 25 are sucked (step 190), and each head is sucked. Timers Te to Th that control the time of suction are reset (step 20).
0). That is, in the initial unused state after replacement, the ink in the ink cartridge is not supplied to the nozzle surface of the head, so suction processing is performed to suck the ink in the ink cartridge to the nozzle surface of the head. , Ready to eject ink.

If it is determined in step 210 shown in FIG. 5 that the ink cartridge of any of the heads has been replaced, the head of the replaced cartridge is suctioned (step 220). A timer that manages the time for suctioning the head is reset (step 230). In other words, when the ink cartridge is replaced, air often enters the head to generate bubbles. Therefore, suction processing is performed to remove the bubbles and bring the ink into a good ejection state.

By the way, in the main flow shown in FIGS. 4 and 5, while there is no print command from the host computer 51, the processes of steps 120, 180, 210 and 240 are repeated so that one of the timers Te to Th is over. When, or when the head is replaced or the ink cartridge is replaced, a predetermined head suction process is executed. Then, the print command from the host computer 51 requires at least the maximum time for managing the flushing (“20 in the present embodiment”).
If the timer is interrupted for more than “second”), the timers Ta to Td reset during the printing immediately before that time all expire during the standby for printing. Therefore, when the next print command is issued, the preliminary ejection process of all the heads is executed in step 130 immediately after it is determined in step 120 that “the print command is present”, and then the process proceeds to step 150. Printing is executed.

As described above, according to the printer of the embodiment of the present invention, it is possible to manage the time for flushing and suction for each head, so that the ink is uniformly ejected or sucked as in the conventional case. It is possible to eliminate wasteful consumption of ink as compared with the case of discarding the ink.

In the embodiment of the invention described above, the case where the time for flushing and purging is controlled for each color of ink has been described. For example, a plurality of inks having the same color but different properties are used together. In the printer, it is also possible to set the time for individual management according to the properties such as the drying time and viscosity of each ink. Further, in the embodiment of the invention described above, steps 131 to 142 and steps 241 to 252 correspond to the maintenance operation executing means according to the present invention.

[0048]

As described above, according to the present invention, since it is possible to manage the maintenance time for each head, wasteful consumption of ink can be eliminated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main structure of a printer according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of the printer shown in FIG.

3 is a block diagram illustrating a gate array 40 in the control system shown in FIG.

FIG. 4 is a main flowchart showing main control contents executed by a CPU.

FIG. 5 is a continuation of the main flowchart of FIG.

FIG. 6 is a flowchart showing a preliminary ejection process.

FIG. 7 is a flowchart showing a suction process.

[Explanation of symbols]

 10 Printer 20 Head (Printing Head) 32 Ink Absorber 34 Suction Cap 35 Purging Mechanism 36 Cap 38 Pump 50 CPU (Maintenance Operation Execution Unit) 67 Timer

Claims (6)

[Claims] 1. A plurality of print heads for performing printing by ejecting different inks from nozzles provided in an ink chamber onto a print medium are provided, and the ink ejection state of each print head is improved. In the inkjet printer provided with a maintenance unit, the maintenance unit executes a predetermined maintenance operation for each print head on the basis of a predetermined time set for each print head and An inkjet printer characterized by a good ejection state. 2. The ink jet printer according to claim 1, wherein the predetermined maintenance operation is to eject a predetermined amount of ink from a nozzle of the print head. 3. The ink jet printer according to claim 1, wherein the predetermined maintenance operation is to suck a predetermined amount of ink in the ink chamber of the print head. 4. The ink jet printer according to claim 1, wherein the predetermined time is set based on a property of ink ejected from each of the print heads. 5. The maintenance means includes a maintenance operation executing means for executing the maintenance operation when an elapsed time from a time when the last maintenance operation is executed to a current time reaches the predetermined time. The inkjet printer according to any one of claims 1 to 4, wherein the inkjet printer is provided. 6. The ink jet printer according to claim 1, wherein each of the print heads ejects ink of a different color.