JP3255479B2 - Inkjet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer for performing a dummy ink discharging operation (purging) for moving a print head to a predetermined position and discharging ink.

[0002]

2. Description of the Related Art An ink jet printer includes a print head provided with a plurality of ink discharge nozzles. The print head is mounted on a carriage and controlled to move along a platen to selectively discharge ink from each nozzle. Dot printing is performed on paper.

In such an ink jet printer, not all nozzles of the print head are always used,
In some cases, nozzles in which ink is not ejected for a long time may occur. If the ink is not ejected for a long time as described above, there is a problem that the nozzle is clogged with the ink.

For this reason, conventionally, a timer is provided, and when the timer measures a predetermined time, if printing is being performed, the printing head is moved to a dummy ink ejection execution position set outside the printing range after printing of the line is completed. The so-called purging operation (dummy ink discharging operation) that moves and discharges ink from all nozzles is performed, and when the purging operation is completed, the print head is returned to the printing operation position and printing is continued to perform control. To prevent clogging.

[0005]

However, if the dummy ink ejection operation is performed during printing as described above, there is a problem that the printing speed of the page during printing is reduced. Also, when printing continuous lines in the vertical direction as in the case of vertical ruled line printing, a slight displacement occurs in the position of the print head due to the execution of the dummy ink discharge operation, the lines are disturbed, and the printing quality is reduced. There was a problem.

[0006] The present invention is by no score and the execution of the dummy ink ejection operation during the printing, it is intended to provide an ink-jet printer capable of improving the printing quality it is possible to improve the printing speed.

[0007]

The invention corresponding to claim 1 is:
A timer is provided, in an ink jet printer that time measured by the timer to perform the dummy ink ejection operation of ejecting an ink moved to a predetermined position the print head to the lapse of a predetermined time, the paper is the timer before the start printing from being inhaled Time checking means for checking the elapsed time or the remaining time up to a predetermined time; and, if the elapsed time checked by the time checking means is equal to or more than a predetermined time or the remaining time is less than a predetermined time, a dummy of the print head before starting printing. A dummy ink ejection forced execution means for forcibly executing an ink ejection operation is provided .
The ink ejection operation is eliminated .

According to a second aspect of the present invention, the sheet is sucked.
A paper width detecting means for detecting the width of the paper to control the movement of the print head before printing starts from the time of the paper width detection by the paper width detecting means, time check to check the remaining time until counting elapsed time or a predetermined time of the timer Means and the time elapsed time checked by the time checking means is equal to or longer than a predetermined time.
A dummy ink discharge forcibly executing means for forcibly executing a dummy ink discharge operation of the print head when the upper or remaining time is less than a predetermined time;
That is, the ejection operation is eliminated .

[0009]

According to the first aspect of the present invention, the timer measures the elapsed time of the timer or the remaining time up to a predetermined time before the start of printing, and based on the checked elapsed time or the remaining time, the print head before the start of printing. Is forcedly executed. For example, when checking the elapsed time, if the elapsed time exceeds a predetermined time, the dummy ink ejection operation of the print head is forcibly executed before printing is started. When checking the remaining time,
If the remaining time is not equal to or longer than a predetermined time, or if not equal to or longer than the standard time required for printing one page, the dummy ink ejection operation of the print head is forcibly executed before printing starts.

According to the present invention, before the start of printing, the elapsed time of the timer or the remaining time up to the predetermined time is checked, and printing is performed when the sheet width is detected based on the checked elapsed time or the remaining time. The dummy ink ejection operation of the head is forcibly executed.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an ink-jet printer. In the figure, reference numeral 1 denotes a CPU (central processing unit) constituting a control unit main body, and 2 denotes a ROM (read) storing program data and the like for the CPU 1 to control each unit. ·only·
3) a RAM (random access memory) provided with a memory for storing dot data for printing and variable data necessary for program control, and a timer 3a for managing a dummy ink ejection operation, and 4) a host computer. And an interface for controlling transmission and reception of data with the host computer. The CPU 1 starts the dummy ink discharging operation every time the timer 3a measures 45 seconds, for example.

[0013] Paper feed motor driving circuit for driving the paper feed motor 6 consisting of a stepping motor in the figure 5 is to feed controls the paper to be printed, for 7 prints the print head 8 having a plurality of ink ejection Deno Zur A carriage driving circuit 9 drives a carriage motor 10 composed of a stepping motor for controlling the movement of a carriage on which the print head 8 is mounted along a platen.

In the drawing, 11 is a paper sensor used for detecting the leading edge of the paper and the presence or absence of the paper, 12 is an encoder for detecting the moving position of the carriage, and 13 is the left and right edges of the paper for detecting the left and right edges of the paper based on the output of the encoder 12. It is a detector.

The paper sensor 11 is connected to an input port 14, the head drive circuit 7 is connected to an output port 15, and the left and right paper edge detector 13 is connected to both the input port 14 and the output port 15. .

The CPU 1 is electrically connected to the ROM 2, RAM 3, interface 4, motor drive circuits 5, 9, input port 14 and output port 15 via a bus line 16.

FIG. 2 shows a carriage 17 on which the print head 8 is mounted. The carriage 17 is also mounted with a paper width sensor 18 constituting a part of the paper left and right edge detector 13.

The carriage 17 moves left and right along a platen as shown by an arrow in the figure, and can move outside a maximum width A in which paper can be inserted. An ink discharge operation execution position B is set, and a sheet left end detection start position and a sheet right end detection end position C are set outside the position. A sheet left end detection end position and a sheet right end detection start position D are set outside the right end of the maximum width A. Is set.

FIG. 3 shows a process when the CPU 1 sucks a sheet. It is checked whether or not the sheet sensor 11 detects the leading edge of the sheet. When the sheet sensor 11 detects the leading edge of the sheet, a sheet width detecting process is performed. . If the paper sensor 11 does not detect the leading edge of the paper even if the paper feed motor 6 is driven in a predetermined step after the start of paper suction, a suction error is determined and error processing (error display or the like) is performed.

In the paper width detection processing, as shown in FIG. 4, first, the carriage 17 is moved to a paper left end detection start position and a paper right end detection end position C. Subsequently, it is checked whether or not the timer 3a has already counted a predetermined time, for example, 20 seconds or more. (Time Check Means) If the time has been measured for 20 seconds or more, the carriage 17 is moved to the dummy ink discharge operation execution position B and the print head 8 is forcibly executed. That is, dummy ink is ejected from all nozzles of the print head 8. (Dummy ink ejection forced execution means) When the dummy ink ejection operation is completed, the timer 3a is reset and restarted.

If the time measured by the timer 3a has not reached 20 seconds, the execution of the dummy ink discharge operation and the restart of the timer 3a are not performed.

Subsequently, the carriage 17 is moved to the paper left end detection end position and the paper right end detection start position D. At this time, the left edge of the sheet is detected by the sheet width sensor 18 and the data is stored in the RAM 3 from the sheet left and right end detector 13 via the input port 14.

Subsequently, the carriage 17 is again moved to the sheet left end detection start position and sheet right end detection end position C. At this time, the right end of the paper is detected by the paper width sensor 18, and the data is stored in the RAM 3 via the input port 14 from the right and left edge detector 13 of the paper.

Thus, the CPU 1 fetches the sheet width data from the RAM 3 at an appropriate timing and grasps the sheet width.

When the above-described paper width detection processing is completed, the RA
Based on the dot data stored in M3, the paper feed motor 6, the carriage motor 10 and the print head 8 are driven to start the printing operation. If the timer 3a measures 45 seconds during the printing operation, the carriage 17 is moved to the dummy ink discharging operation execution position B and the print head 8 executes the dummy ink discharging operation.

In the embodiment having such a configuration, when a sheet is sucked for printing, the sheet sensor 11 detects the leading edge of the sheet, and the sheet width detecting process is started. In this paper width detection process, the carriage 17 is once moved to the paper left end detection start position and the paper right end detection end position C, and then moved from the position C to the paper left end detection end position and the paper right end detection start position D. With paper width sensor 18
Detects the left end of the sheet. Further, the sheet is moved from the position D to the sheet left end detection start position and the sheet right end detection end position C again.

In this way, the sheet width data from the sheet left and right edge detector 13 is temporarily stored in the RAM 3 via the input port 14, and is read out by the CPU 1 at an appropriate timing to grasp the sheet width.

In this paper width detection process, it is determined whether or not to execute the dummy ink discharging operation at the same time based on the time measured by the timer 3a. That is, it is checked whether or not the timer 3a has already timed for more than 20 seconds.
If the time has been measured for more than one second, the carriage 17 is moved to the dummy ink discharge operation execution position B before the carriage 17 is moved to the paper left end detection end position and the paper right end detection start position D to force the print head 8 to execute the dummy ink discharge operation. .

When the dummy ink discharge operation is completed, the timer 3a is reset and restarted, and the carriage 17 is moved to the paper left end detection end position and the paper right end detection start position D.

As described above, the time counted by the timer 3a is checked at the same time as the paper width detection processing. If the time has been measured for 20 seconds or more, the dummy is read before the carriage 17 is moved to the paper left end detection end position and the paper right end detection start position D. Since the print head 8 is moved to the ink discharge operation execution position B and the print head 8 is forcibly executed, the next dummy ink discharge operation is executed by the timer 3a.
This is the time when 45 seconds have been counted again, and during this time, if normal character printing is performed, printing of one page can be completed sufficiently. Then, when printing the next one page, the paper width detection process is similarly performed before the start of printing. Therefore, also at this time, the dummy ink ejection operation is performed at the time of the paper width detection process. Does not execute the dummy ink discharge operation.

Therefore, the speed of page printing is not reduced by the execution of the dummy ink discharging operation, and the printing speed can be improved. Further, since the dummy ink ejection operation is not performed during the printing of one page, the printing of the vertical ruled line can be satisfactorily performed without causing a positional shift, and the printing quality can be improved.

Further, since the dummy ink discharge operation is executed by using the paper width detection processing which is normally performed, it is not necessary to set a separate process for executing the dummy ink discharge operation. In this case, it is possible to prevent the speed of the entire printing from decreasing.

[0033]

In this embodiment, the determination as to whether or not to execute the dummy ink discharge operation during the paper width detection processing is made based on the time measured by the timer 3a.
May be determined based on a predetermined time, that is, the remaining time until 45 seconds are measured. That is, in the case of the embodiment, if the remaining time is not more than 25 seconds, the dummy ink discharging operation is executed.

In this embodiment, the time for executing the dummy ink discharging operation managed by the timer 3a is set to 45 seconds, and the time for executing the dummy ink discharging operation in the paper width detecting process is set to 20 seconds. Time is, of course, not necessarily limited to a value derived from repeated experiments.

Next, another embodiment of the present invention will be described with reference to the drawings. In this embodiment, 1
An application to a page printer type ink jet printer that receives dot data in page units and performs printing in page units will be described.

In this type of ink jet printer, a buffer having a capacity of one page is provided, and dot data transmitted from the host computer in units of one page is stored in this buffer. As shown in FIG. When the dot data is received, the time required to print the received dot data for one page is calculated.

In the paper width detection process performed when the leading edge of the paper is detected by the paper sensor 11 when the paper is sucked, the remaining time until the predetermined time of the timer 3a is measured and the time required for printing are compared as shown in FIG. , Timer 3a
When the remaining time is shorter than the time required for printing, the dummy ink ejection operation execution position B is required before the carriage 17 is moved to the paper left end detection end position and the paper right end detection start position D.
To force the print head 8 to execute the dummy ink discharge operation.

In this way, when the data amount of one page is relatively small and the time required for printing one page is short, even if the remaining time of the timer 3a is less than 25 seconds, the dummy ink discharge operation is performed during the paper width detection processing. Is not executed,
An efficient dummy ink discharge operation can be performed, and the printing speed can be further improved.

In this embodiment, it is needless to say that the printing quality can be improved in printing vertical ruled lines.

In each of the above embodiments, the forcible execution of the dummy ink ejection operation is performed during the paper width detection processing. However, the present invention is not limited to this. The paper width is not limited until the printing of one page is started. It does not have to be during the detection process.

[0042]

According to the present invention as described in detail above, to eliminate the execution of the dummy ink ejection operation during printing
Accordingly, it is possible to provide an ink jet printer that can improve the printing speed and the printing quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship among a carriage and a maximum width of a sheet, a dummy ink discharge operation execution position, and a sheet left and right end detection position according to the embodiment.

FIG. 3 is a flowchart showing a sheet suction process of the embodiment.

FIG. 4 is a flowchart showing a sheet width detection process in FIG. 3;

FIG. 5 is a flowchart showing main part processing at the time of data reception in another embodiment of the present invention.

FIG. 6 is a flowchart showing a sheet width detection process of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU (Central processing unit) 2 ... ROM (Read only memory) 3a ... Timer 8 ... Print head 10 ... Carriage motor 11 ... Paper sensor 13 ... Paper left and right edge detector 17 ... Carriage 18 ... Paper width sensor

Claims (2)

(57) [Claims] An ink jet printer is provided with a timer, and when a time measured by the timer elapses a predetermined time, a print head is moved to a predetermined position to execute a dummy ink discharge operation for discharging ink, and paper is sucked.
The timer and time checking means for checking the remaining time until counting elapsed time or a predetermined time, counting elapsed time checked this time checking means before starting printing from
When is the time remaining or more than a predetermined time is less than the predetermined time, provided the dummy ink ejection forcing means for forcing the dummy ink ejection operation of the print head before starting the printing, 1
An ink jet printer , wherein a dummy ink ejection operation during printing of a page is eliminated . Wherein providing a timer, the inkjet printer time measured by the timer to perform the dummy ink ejection operation of ejecting an ink moved to a predetermined position the print head to the lapse of a predetermined time, the sheet is sucked
Checking and paper width detecting means, when the paper width detection by the paper width detecting means, the time remaining until counting elapsed time or a predetermined time of the timer by moving control the print head before printing starts detecting the width of the paper from Time checking means to perform and the time elapsed time checked by the time checking means
A dummy ink ejection forcibly executing means for forcibly executing a dummy ink ejection operation of the print head when the remaining time is equal to or longer than a predetermined time or less than the predetermined time .
An ink jet printer characterized by eliminating the dummy ink ejection operation in the printer.