JP2002036581A - Ink jet recording device - Google Patents

Abstract

(57) [Summary] To improve the throughput by adjusting the execution timing of a flushing operation. SOLUTION: The timing of a flushing operation for idly discharging ink droplets from a recording head is adjusted so as to be executed during a page break operation of recording paper as indicated by a mark. By making such adjustments, it is possible to reduce the chances of entering a regular flushing operation during the printing operation of the recording paper, thereby contributing to improving the throughput.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus having a recording head which prints an image on recording paper by discharging ink droplets from nozzle openings, and more particularly to clogging of the recording head due to thickening of ink. The present invention relates to a technique for controlling a flushing operation for preventing the flashing.

[0002]

2. Description of the Related Art A recording head used in an ink jet type recording apparatus discharges ink pressurized in a pressure generating chamber from a nozzle as ink droplets onto recording paper to perform printing. There is a problem that a printing failure occurs due to an increase in ink viscosity, solidification of the ink, adhesion of dust, and mixing of air bubbles. For this purpose, the ink jet recording apparatus is provided with a capping means for sealing the nozzle openings of the recording head during non-printing, and a wiping member for cleaning the nozzle forming surface as required.

[0003] The capping means not only functions as a cover for sealing the recording head during printing suspension and preventing the ink from being dried at the nozzle opening, but also when the nozzle opening becomes clogged. Is to seal the nozzle formation surface of the recording head, suck ink from the nozzle openings by negative pressure from the suction pump, and clog the nozzle openings due to solidification of the ink, or poor ink ejection due to air bubbles entering the ink flow path. It also has a function to eliminate the problem.

The forcible suction / discharge process of ink for eliminating the clogging of the recording head and the mixing of air bubbles into the ink flow path is called a cleaning operation. This is executed when restarting the printing operation or when the user recognizes that the quality of the recorded image has deteriorated and operates the cleaning switch. An operation of wiping (wiping) the nozzle forming surface by a wiping member made of a plate is involved.

[0005] The recording head is also provided with a function of applying a drive signal unrelated to printing and causing ink droplets to be ejected idly, which is called a flushing operation. As a result, the uneven meniscus near the nozzle opening of the recording head caused by this may be recovered, the mixed color ink flowing backward from the nozzle by the wiping operation may be ejected, and the ink may be ejected at the nozzle opening with a small ejection amount of the ink droplet during printing. It is configured to be executed at regular intervals for the purpose of preventing clogging due to thickening.

[0006]

By the way, the above-mentioned flushing operation is controlled so as to be executed at regular intervals, for example, every 12 seconds as described above while the printing operation is continued. Therefore, while the printing operation of the first page is completed and the recording paper of the first page is discharged, and the recording paper of the second page is supplied, the timer is set to perform the next flushing operation. An operation of continuously counting up is performed. Therefore, when the printing operation of the second page of the recording paper is started,
The flushing operation may be started soon, and there is a factor that the throughput cannot be improved.

FIG. 6 shows an example of this. For example, the printing operation of the first page is started, and after 12 seconds, a flushing operation is executed as indicated by a black circle.
While the printing operation for the first page is completed and the recording paper for the first page is discharged, and while the recording paper for the second page is supplied, the timer is set to perform the next flushing operation. The operation of continuously counting up is continued. Then, when the printing operation of the second page of the recording paper is started, the flushing operation indicated by the black mark is executed again because 12 seconds have elapsed since the previous flushing operation.

In FIG. 6, the period of the flushing operation is indicated by one point indicated by a black circle. However, when the flushing operation is performed, the carriage is moved to a predetermined flushing position so that An operation is performed to execute idle discharge of ink droplets and return the carriage to the print position where printing was interrupted again. Therefore, the time axis shown in FIG. 6 actually becomes longer, and it is difficult to improve the throughput. In addition, the example shown in FIG. 6 shows a case where the printing speed is relatively low. Therefore, a flushing operation is further performed just before the printing of the second page of recording paper is completed, and the throughput is further reduced. A situation occurs in which it drops.

On the other hand, in this type of ink jet recording apparatus, it is desired to increase the printing speed, and recently, for example, a specification of about 12 PPM (one page is printed in 5 seconds) is required. . In order to satisfy such specifications, it is impossible to realize this in the above-described control mode of the flushing operation.

An object of the present invention is to solve the technical problem as described above, and an ink jet recording apparatus capable of improving the throughput particularly at high speed printing by adjusting the timing of the flushing operation. The purpose is to provide.

[0011]

In order to achieve the above-mentioned object, an ink jet recording apparatus according to the present invention is mounted on a carriage moving in the width direction of a recording sheet, and ejects ink droplets from nozzle openings. An ink jet recording head that prints an image on a recording sheet, and supplies a flushing drive signal to the recording head, so that a flushing operation of idly discharging ink droplets from a nozzle opening of the recording head is performed. An ink jet recording apparatus, characterized in that an adjusting means for adjusting the flushing operation so that the flushing operation is performed during a period of discharging and feeding a recording sheet is provided.

In this case, in a preferred embodiment, the flushing operation is executed every time a first predetermined time is counted from the previous flushing operation while the printing operation is continued, and the recording paper is discharged. In addition, when the paper feeding period has been reached, the flushing operation is performed again before the first predetermined time is measured. Further, in this case, preferably, the timing of the first predetermined time is started again from the flushing operation executed during the period of discharging and feeding the recording sheet.

According to the above-described configuration, if it is assumed that the first predetermined time is 12 seconds, that is, the flushing operation is performed every 12 seconds during the continuation of the printing operation, one page is deleted by 12 seconds. Less than seconds (= 5 PPM
In the recording apparatus capable of printing as described above, flushing is always performed during the period of discharging and feeding the recording paper. Therefore, in the recording apparatus having the high-speed printing function described above, the flushing operation is not performed during the printing of the page, and the throughput can be further improved.

In another preferred embodiment of the present invention, the flushing operation is executed every time a first predetermined time is counted from the previous flushing operation while the printing operation is continued. In the case where the period of discharging and feeding of the recording sheet has been reached, the flushing operation is performed again when the second predetermined time shorter than the first predetermined time is measured. Further, in this case, preferably, the timing of the first and second predetermined times is started again from the flushing operation executed during the period of discharging and feeding the recording sheet.

In the recording apparatus configured as described above,
If the first predetermined time is set to 12 seconds in the same manner as described above and the second predetermined time is set to, for example, 5 seconds, when the period for discharging and feeding the recording paper is reached, 5 seconds from the previous flushing operation is performed. , The flushing operation is performed. In other words, if five seconds have not elapsed since the previous flushing operation, the flushing operation is not performed during the period during which the recording paper is discharged and fed. Even in such a configuration, for example, in a recording apparatus having a function of printing one page in 5 seconds (= 12 PPM), the flushing operation is not performed during the printing of the page, thereby improving the throughput. be able to.

Further, according to the latter recording apparatus, the flushing operation is not necessarily performed during the period of discharging and feeding the recording paper, so that the waste of ink due to the flushing operation can be suppressed, and the running can be suppressed. This can contribute to reducing costs.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 shows a configuration of a recording apparatus main body to which the present invention can be applied. In FIG. 1, reference numeral 1 denotes a carriage. The carriage 1 is guided by a carriage shaft 4 horizontally supported and supported by left and right frames 2 and 3 via a timing belt driven by a carriage motor described later. It is configured to be reciprocated.

An ink jet recording head 5 is mounted on the carriage 1 downward, and a black ink cartridge 6 for supplying ink to the recording head 5 and a color ink cartridge 7 are detachably mounted on an upper portion thereof. Loaded as possible. Below the recording head 5, a paper guide member 8 is arranged corresponding to the scanning direction. A recording paper 9 is placed on the paper guide member 8, and the recording paper 9 is a paper not shown. The feeding unit is configured to be conveyed in a direction orthogonal to the scanning direction of the recording head 5.

In the drawing, reference numeral 10 denotes capping means disposed in a non-printing area (home position), which can seal the nozzle forming surface of the recording head 5 when the recording head 5 moves directly above. It is configured to be able to. Below the capping means 10, a suction pump 11 for applying a negative pressure to the internal space of the capping means 10 is arranged. The capping unit 10 functions as a lid for sealing the nozzle forming surface of the recording head 5 to prevent the nozzle openings of the recording head 5 from drying during the suspension period of the recording apparatus. The pressure also acts on the recording head 5 to perform a cleaning operation of sucking and discharging ink from the recording head.

In the vicinity of the capping means 10, a wiping member 12 formed of an elastic plate made of rubber or the like in a strip shape is disposed so as to be able to advance and retreat with respect to the movement locus of the recording head 5. When reciprocating to the capping unit 10 side, a wiping operation for wiping the nozzle forming surface of the recording head 5 is performed as necessary.

On the other hand, a flushing area 13 is formed in the other non-printing area facing the capping means 10 via the central printing area. This flushing area 13 is constituted by an opening hole formed in the paper guide member 8. And, at the inner bottom portion of the opening hole 13,
A waste liquid absorber 14 is disposed to absorb and hold the ink waste liquid sucked and discharged by the pump 11 in the internal space of the capping means 10. The waste material 14 is disposed along the longitudinal direction of the paper guide member 8. It is stored in the tank 15.

FIG. 2 shows an example of a control circuit mounted on the recording apparatus having the above-described configuration. In FIG. 2, the recording head 5, the ink cartridges 6, 7, the capping means 10, the suction pump 11, and the waste liquid tank 15 containing the waste liquid absorbing material 14, which have already been described, are denoted by the same reference numerals. Omitted.

In FIG. 2, reference numeral 30 denotes print control means. The print control means 30 generates bitmap data based on print data from a host computer.
A function is provided in which a drive signal is generated by the head drive unit 31 based on this data, and ink droplets are ejected from the recording head 5. The head driving unit 31 receives a flushing command signal from the flushing control unit 32 and outputs a drive signal for a flushing operation to the recording head 5 in addition to a drive signal based on print data, and has no relation to printing. It is also configured to be able to perform idle discharge of ink.

Reference numeral 33 denotes cleaning control means.
The pump drive means 34 is operated by a command from the cleaning control means 33, and the drive of the suction pump 11 is controlled. The cleaning control unit 33 is configured to be supplied with a command signal from the printing control unit 30 and the cleaning command detection unit (CL command detection unit) 35. Note that a command switch 36 is connected to the cleaning command detection means 35,
When the user pushes the switch 36, for example, the command detecting means 35 is operated to execute a manual cleaning operation.

A carriage control means 37 is connected to the print control means 30 and the flushing control means 32, and a control signal for moving the carriage to, for example, a home position is transmitted from the print control means 30 at the timing of a page break. Is done. At the time of a flushing operation, a control signal is sent from the flushing control means 32 to the carriage control means 37, thereby driving the carriage motor 38 and causing the carriage 1 to operate.
Is controlled so as to move the recording head 5 mounted on the paper guide member 8 immediately above the flushing area 13 formed in the paper guide member 8.

A flushing timer 39 is connected to the flushing control means 32. The flushing timer 39 is reset when the flushing operation is performed by the flushing control means 32, and the elapsed time is counted up after the flushing operation is performed. It is made to do. Then, as described later, when a predetermined time has elapsed, the flushing control means 32 is activated to perform a flushing operation.

FIG. 3 shows a recording head flushing operation routine performed in the above configuration.
FIG. 3 shows an example in which the printing of the second page is started from the time when the printing operation of the first page is completed when printing a plurality of pages. However, the printing operation of the second page is completed. When the printing of the third page is started, and thereafter, the same operation is performed as described below.

When the printing operation of the first page is completed, control is performed so that the two routines shown in FIG. First, when the printing operation of the first page is completed, the sheet of the first page is discharged from the recording apparatus in step S11 shown as. Subsequently, as shown in step S12, the sheet of the second page is loaded (supplied) to the recording apparatus. In step S13 shown in parallel with this, an operation is performed to move the carriage 1 to the standby position. This is because the print control unit 30 sends the carriage control unit 3
7 by sending a control signal.

Subsequently, the carriage 1 is moved to the flushing position as shown in step S14, and the flushing operation is executed as shown in step S15. After this flushing operation, as shown in step S16, the carriage is moved to the standby position again, and the system is ready to start the printing operation of the next second page.

FIG. 5A shows the timing of the flushing operation when the above control routine is executed. The example shown in FIG. 5A shows a case where the flushing interval (first predetermined time) measured by the flushing timer 39 is set to 12 seconds. 5 shows a case where the present invention is applied to a recording apparatus of 5 PPM (a recording apparatus for printing one page in 12 seconds). When the printing operation of the first page is started as shown in FIG. 5A, as shown in FIG.
The printing operation is completed within about 0 seconds. Then, the sheet of the first page is discharged, and the sheet of the second page is fed.

At this time, according to the control routine shown in FIG.
The flushing operation is performed as indicated by the mark. That is, the flushing is executed in a state where the first predetermined time measured by the flushing timer 39 is less than 12 seconds. In this state, the flushing timer 39
Is reset and time counting is started again. Then, the printing operation of the second page is executed, and in a state where the printing operation is completed and the sheet is discharged, about 12 seconds have elapsed since the previous flushing operation.

In this state, the flushing operation is executed again, as indicated by the black circle, in order to enter the period of paper ejection and paper feeding. In this case, as described above, the flushing timer 39 measures approximately 12 seconds, and if the timing reaches even slightly earlier, the flushing operation is executed by a command from the flushing timer 39. Such an operation is repeatedly performed until the end of all printing, and therefore, the flushing operation is performed only during the sheet discharging and paper feeding periods.

The timing chart shown in FIG. 5A is applied to a recording apparatus having a printing speed of 5 PPM as described above, and a recording apparatus having a printing speed higher than that, ie, printing of one page. When the present invention is applied to a recording apparatus that is executed for a time of 12 seconds or less, flushing is always executed during a paper discharge and paper feed period. Therefore, flushing is not performed during printing of the page, and the throughput can be improved.

According to the above configuration, although the throughput can be improved, the flushing is executed every time during the paper discharging and paper feeding periods, and there is a problem that the waste of ink becomes a problem. . Thus, the control routine shown in FIG. 4 is designed to solve such a problem. The difference between the control routine shown in FIG. 4 and the routine shown in FIG. 3 is that a determination unit shown in step S21 is added between steps S13 and S14.

That is, here, it is determined whether or not a second predetermined time (X seconds) has elapsed since the previous flushing operation. Then, if it is determined that the second predetermined time has elapsed (Yes), step S1 is executed.
The control routine after step 4 is entered, and flushing is executed during the sheet discharging and sheet feeding periods. Step S
At 21, the second predetermined time has not elapsed (N
If it is determined to be o), the printing of the next page is started without executing the flushing operation.

The second predetermined time is measured by a flushing timer 39 shown in FIG. 2, and the flashing operation is performed in the same manner as the first predetermined time (12 seconds). It is reset by execution, and is controlled to start timing again. Such a control routine is particularly effective when used in a printing apparatus having a high printing speed. For example, the present invention is applied to a recording apparatus having a printing capability of 12 PPM or more, and the timing chart of the flushing operation when the second predetermined time (X seconds) is set to be shorter than the first predetermined time, for example, 5 seconds. , FIG. 5 (B).

As shown in FIG. 5B, during the period in which printing on the page before the nth page is completed and the sheet is discharged and the nth page is fed, flushing is performed as indicated by a black circle. Assuming that the action has been performed,
In a recording device having a printing capability of 2 PPM or more,
In the period in which the recording paper of the nth page is discharged and the recording paper of the (n + 1) th page is fed, the above-mentioned second predetermined time (5 seconds) has not elapsed. Therefore, in step S21 in FIG. 4, it is determined that the second predetermined time has not elapsed (less than 5 seconds), and at this timing, the flushing operation is not performed as indicated by a circle.

Subsequently, in the period in which the printing of the (n + 1) th page is completed and discharged, and the recording sheet of the next page is fed, the second predetermined time (from the previous flushing operation) is counted from the previous flushing operation. 5 seconds), and therefore, at this timing, the flushing operation is performed as indicated by the mark ●. Note that, in this case, although counting from the previous flushing operation is shorter than the first predetermined time (12 seconds), the flushing is executed, and the clocking operation of the first predetermined time and the clocking operation of the second predetermined time are performed. The timing operation is reset together.

As a result, in the recording apparatus having the above-mentioned specifications, the flushing operation is executed at every other ejection and feeding timing. As a result, the number of flushing operations can be reduced without lowering the throughput, and waste of ink can be suppressed.

[0040]

As is apparent from the above description, according to the ink jet type recording apparatus of the present invention, the flushing operation is executed when the period of recording paper discharge and paper supply is reached. Therefore, in a recording apparatus having a relatively high-speed printing function, the flushing operation is not performed during the printing operation of one page of recording paper, thereby improving the throughput. Further, by providing the function of counting the second predetermined time, it is possible to prevent the flash sync operation from being executed for each page break, and to suppress waste of ink.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an ink jet recording apparatus to which the present invention can be applied in a partially broken state.

FIG. 2 is a block diagram illustrating an example of a control circuit installed in the recording apparatus illustrated in FIG.

FIG. 3 is a flowchart showing a flushing operation routine of the recording head performed by the control circuit shown in FIG. 2;

FIG. 4 is a flowchart illustrating another flushing operation routine of the recording head performed by the control circuit illustrated in FIG. 2;

FIG. 5 is a timing chart of a flushing operation performed by the operation routine shown in FIGS. 3 and 4;

FIG. 6 is a timing chart of a flushing operation performed by a conventional recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Carriage 4 Carriage shaft 5 Recording head 6 Black ink cartridge 7 Color ink cartridge 8 Paper guide member 9 Recording paper 10 Capping means 11 Suction pump 12 Wiping member 13 Flushing area 14 Waste liquid absorbing material 15 Waste liquid tank 30 Printing control means 31 Head driving means 32 Flushing control means 33 Cleaning control means 34 Pump driving means 35 Cleaning command detection means 36 Command switch 37 Carriage control means 38 Carriage motor 39 Flushing timer

Claims (5)

[Claims] An ink jet recording head is mounted on a carriage that moves in the width direction of a recording sheet and prints an image on the recording sheet by ejecting ink droplets from nozzle openings, and a flushing drive signal is sent to the recording head. An ink jet recording apparatus configured to perform a flushing operation of idly discharging an ink droplet from a nozzle opening of a recording head by supplying the recording paper, wherein the flushing operation is performed during a period of discharging and feeding a recording sheet. An ink jet recording apparatus, comprising: an adjusting unit for performing an adjustment so as to be executed. 2. The flushing operation is executed every time a first predetermined time is counted from the previous flushing operation during the continuation of the printing operation, and the flushing operation reaches a period of discharging and feeding a recording sheet. 2. The ink jet recording apparatus according to claim 1, wherein in such a case, the flushing operation is performed again before the first predetermined time is measured. 3. A method according to claim 1, wherein the flushing operation performed during a period of discharging and feeding the recording sheet is performed.
3. The ink jet recording apparatus according to claim 2, wherein the timing of the first predetermined time is started again. 4. The flushing operation is executed each time a first predetermined time is measured from the previous flushing operation during the continuation of the printing operation, and the flushing operation reaches a period for discharging and feeding a recording sheet. 2. The ink jet recording apparatus according to claim 1, wherein the flushing operation is executed again when a second predetermined time shorter than the first predetermined time is measured. 5. A method according to claim 1, wherein said flushing operation is performed during a period of discharging and feeding a recording sheet.
5. The ink jet recording apparatus according to claim 4, wherein timing of the first and second predetermined times is started again.