JPH106531A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the forcible ink discharge operation by the proper timing in compliance with the condition at the time of completing the recording or in the state of leaving a device as it is. SOLUTION: The time of leaving a device as it is after completing the recording operation is counted by a time counting section 3. Ink in a jet opening section of a recording head 2 is sucked and discharged forcibly by a recovery device 4 to recover the function of the recording head 2. The recovery device 4 is controlled by a discharge control section 5 and the ink is discharged forcibly from the recording head 2. The temperature in the recording head 2 is sensed by a temperature sensor 6. The time count value for the leaving time counted by the time count section 3 is compared with the reference value kept in a reference value keeping section 51 by a comparison section 52, and when the time count value reached the reference value, the recovery value 4 is driven to discharge ink forcibly. Based on the temperature information in the recording head at the time of completing the recording provided by the temperature sensor 6, at least either of the leaving time or the set time of the reference value input into the comparison section 52 is multiplied by the weighting coefficient by a weight correction section 53 to correct the leaving time for the forcible discharge.

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 for recording on a recording material by discharging ink from a recording head, and more particularly to an improvement in a cleaning technique for a recording head.

[0002]

2. Description of the Related Art Recording devices such as printers and plotters used as output devices such as computers, word processors and workstations, or recording devices in copiers and facsimile machines, etc., use a recording medium, ie, a recording medium, based on given image information. An image including characters or symbols is recorded on the material. As the recording material, recording paper made of paper such as plain paper or special paper, OHP (overhead projector) paper, or a thin plastic sheet used as some special paper is used. The recording apparatus is an ink jet type, a wire dot type, and a thermal type (including a thermal transfer type) depending on a recording type.
Or it is roughly classified into a laser beam type or the like.

A recording apparatus of a type called a serial type or the like employs a recording method in which a recording material is conveyed in a direction intersecting a main scanning direction, which is a direct scanning by a recording head, to perform a sub-scan. In a recording apparatus of this type, after a recording material is set at a predetermined recording position, an image (including characters or symbols) is recorded by a recording head mounted on a carriage that moves along the recording material ( After the recording of one line is completed, a predetermined amount of paper feeding (sub-scanning) is performed, and then the operation of recording the image of the next line (main scanning) is repeated. An image is recorded in a desired range. On the other hand, the recording material is set at a predetermined recording position, and the recording unit is arranged in the entire scanning direction of the recording material without scanning the recording head. There is also a recording apparatus of a type that performs pitch feeding for feeding a predetermined amount at a time and records an image on the entire recording material.

An ink-jet recording apparatus, which is an ink-jet recording apparatus, performs recording by ejecting ink from a recording head onto a recording material by mechanical movement or heating. This inkjet recording device
It is easy to make the recording head compact, can record high-definition images at high speed, can record on plain paper without special processing, has low running cost, and is a non-impact method. Therefore, there are advantages such as low noise and easy recording of a color image using multicolor inks.

[0005] In particular, an ink jet recording head that uses heat energy to heat the vicinity of a nozzle, which is an ink discharge hole, to discharge ink, includes etching, vapor deposition,
Through semiconductor manufacturing processes such as and sputtering,
By forming an electrothermal transducer, an electrode, a liquid path wall, a top plate, and the like formed on a substrate, a high-density liquid path arrangement, that is, one having a nozzle arrangement can be easily manufactured. Can be made more compact. further,
By utilizing IC (integrated circuit) technology and micro-machining technology, the recording head can be easily made longer and two-dimensional, that is, planarized. Is also easy.

In such an ink jet recording apparatus, since recording is performed by directly discharging ink, which is a recording liquid, from nozzles of a recording head, it is necessary to always maintain a state in which ink can be discharged. There are special problems not found with other recording devices.

For example, when air bubbles are mixed into an ink supply path for supplying ink to a nozzle which is an ejection hole or an ink reservoir called a common liquid chamber near the nozzle, and the air bubble becomes a certain size, the air bubbles enter the nozzle. The ink may not be ejected due to, for example, obstructing the supply of the ink.

[0008] The causes of the air bubble mixing are as follows: (1) Atmosphere enters the recording head.

The portion forming the above-described ink supply path and the common liquid chamber is composed of a plurality of members, and the gap between the joints of the members is closed with a sealing material. The pressure inside the recording head is kept lower than the atmospheric pressure in order to prevent ink leakage or for other reasons. for that reason,
Gas such as air enters the recording head from a very small gap in the sealing material or the sealing portion.

(2) Dissolved gas dissolved in the ink is generated as bubbles.

The dissolved gas dissolved in the ink saturates due to an increase in the temperature of the ink and cannot be dissolved.
Bubbles are generated in the ink and accumulated near the ink supply path and the nozzle.

Conventionally, it is difficult to directly detect the presence and size of bubbles in a print head in order to solve such a problem. For example, when ink is not ejected for a long period of time, For example, the idle time is measured, and when the idle time exceeds a predetermined time, a forced ink discharge operation such as suction of ink is performed to forcibly discharge bubbles due to gas entering the ink together with the ink. The method was taken.

[0013]

However, in the case where the leaving time is measured as in the prior art and the forced discharge operation is performed when the leaving time exceeds a predetermined time, the situation immediately before the The method of generating bubbles varies depending on conditions such as the history until the discharge is performed and changes in the environment during leaving, so that there is a problem that the time required for causing inconvenience in ejection varies. For this reason, under certain conditions, bubbles in the print head grow before the forced discharge operation is performed, and it becomes impossible to discharge ink from the nozzles. Conversely, under other conditions, the forced discharge operation is performed even when the bubble has not yet grown and recording can be continued without performing the forced discharge operation. Is wasted and the running cost is reduced.

SUMMARY OF THE INVENTION The present invention has been made to address the above-described problem, and an ink jet recording apparatus capable of performing a forced discharge operation at an appropriate timing according to conditions of a state before leaving or during leaving is provided. It is intended to provide.

[0015]

In order to achieve the above object, an ink jet recording apparatus according to a first aspect of the present invention has a discharge head and performs recording by discharging ink from the discharge hole. Recovery means for forcibly discharging ink from at least the ejection holes of the printhead; time detection means for detecting an elapsed time from a previous forcible discharge operation by the recovery means; and Temperature detecting means for detecting the temperature inside the head, the elapsed time detected by the time detecting means is compared with a predetermined value, and when the elapsed time exceeds a predetermined value, the recovery means performs a forced discharge operation, Correcting at least one of the elapsed time and a predetermined value in accordance with the temperature of the recording head at the time of completion of the recording detected by the temperature detecting means, It is characterized by comprising a control means for performing control for adjusting the time interval from the end to the forcible discharge operation by the recovery unit.

The ink jet recording apparatus further comprises a counting means for counting the number of times of ink ejection from the last forcible discharge operation by the recovery means to the end of the last recording, and the control means comprises a discharging means for discharging the ink by the counting means. A means for correcting at least one of the elapsed time and a predetermined value according to a count value of the number of times may be included.

The ink jet recording apparatus further includes an environmental temperature detecting means for detecting an environmental temperature around the recording head at least for a predetermined period after the end of the last recording, and the control means detects the environmental temperature by the environmental temperature detecting means. A means for correcting at least one of the elapsed time and a predetermined value according to the environmental temperature to be performed may be included.

[0018] The ink jet recording apparatus further comprises an air pressure detecting means for detecting an air pressure around the recording head at least during a predetermined period after the end of the last recording, and the control means comprises a pressure detecting means for detecting the air pressure detected by the air pressure detecting means. Means for correcting at least one of the elapsed time and a predetermined value in accordance with

An ink jet recording apparatus according to a second aspect of the present invention has a recording head which has an ejection hole and performs recording by intermittently ejecting ink from the ejection hole, and at least the inside of the ejection hole of the recording head. Recovery means for forcibly discharging ink, time detection means for detecting the elapsed time from the previous forced discharge operation by the recovery means, and ink discharge from the previous forced discharge operation by the recovery means to the end of the last recording The counting means for counting the number of times, the elapsed time detected by the time detecting means is compared with a predetermined value, and when the elapsed time exceeds a predetermined value, a forced discharge operation is performed by the recovery means, and At least one of the elapsed time and the predetermined value is corrected according to the count value of the number of times of ejection, and the time from the end of the recording to the forced ejection operation by the recovery unit is corrected. It is characterized by comprising a control means for performing control to adjust the spacing.

An ink jet recording apparatus according to a third aspect of the present invention has a discharge head having a discharge hole for discharging ink from the discharge hole, and forcing ink in at least the discharge hole of the recording head. Recovery means for discharging, time detecting means for detecting an elapsed time from a previous forcible discharging operation by the recovery means, and environmental temperature detection for detecting an environmental temperature around the recording head at least for a predetermined period after the end of the last recording. Means for comparing the elapsed time detected by the time detecting means with a predetermined value, and when the elapsed time exceeds the predetermined value, the recovery means performs a forced discharge operation and is detected by the environmental temperature detecting means. At least one of the elapsed time and the predetermined value is corrected according to the environmental temperature, and the time from the end of the recording to the forced ejection operation by the recovery unit is corrected. It is characterized by comprising a control means for performing control to adjust the spacing.

[0021] The environmental temperature detecting means may include means for detecting at least one of the temperature inside and outside the ink jet recording apparatus.

According to a fourth aspect of the present invention, there is provided an ink jet recording apparatus having a discharge hole for discharging ink from the discharge hole to perform recording, and forcing ink in at least the discharge hole of the recording head. Recovery means for discharging, time detection means for detecting the elapsed time from the previous forced discharge operation by the recovery means, and pressure detection means for detecting the pressure around the recording head at least for a predetermined period after the end of the last recording. Comparing the elapsed time detected by the time detecting means with a predetermined value, and when the elapsed time exceeds the predetermined value, causes the recovery means to perform a forced discharge operation, and according to the air pressure detected by the air pressure detecting means, And correcting at least one of the elapsed time and the predetermined value to adjust a time interval from the end of the recording to the forced ejection operation by the recovery unit. It is characterized by comprising a control means for performing control.

[0023] The air pressure detecting means may include means for detecting at least one of an external pressure and an internal pressure of the ink jet recording apparatus.

The control means may include means for making a correction by applying a weighting factor based on a standard state to at least one of the elapsed time to be compared and a predetermined value.

The ink jet recording apparatus according to the present invention comprises:
At least one of the elapsed elapsed time and a predetermined value serving as a comparison reference is corrected according to the idle condition, and the time interval from the end of recording to the forced ejection operation is appropriately adjusted to perform the forced ejection operation.

With this control, the degree of change of the dissolved gas into bubbles based on the temperature of the recording head at the end of recording changes, and the sealing material based on the amount of gas in the head accompanying the print amount until the end of recording. Considering conditions such as changes in the degree of mixing of outside air, changes in the degree of dissolved gas becoming bubbles based on temperature changes during standing, and changes in the degree of outside air mixing into the head based on changes in atmospheric pressure during standing The proper forced discharge operation is performed within the appropriate leaving time. Therefore, it is possible to prevent the ink from being wastefully discharged by the premature forced discharge operation, and to prevent the occurrence of a defective recorded image due to bubbles generated by the prematurely forced discharge operation.

[0027]

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

[First Embodiment] An ink jet recording apparatus according to a first embodiment of the present invention will be described with reference to FIGS. The ink jet recording apparatus according to the first embodiment of the present invention is configured as, for example, an ink jet type plotter.

FIG. 1 shows a functional configuration of an ink-jet plotter according to a first embodiment of the present invention, FIG. 2 shows a configuration near a recording portion thereof, and FIG. 3 shows a cross-section of a schematic configuration near a recording head and a recovery device. Are schematically shown.

The ink jet plotter shown in FIG.
A recording control unit 1, a recording head 2, a timing unit 3, a recovery device 4,
An emission control unit 5 and a temperature sensor 6 are provided.

The recording control unit 1 is a part for controlling basic operations as a plotter, and controls input processing from outside, signal processing for recording based on the input processing, driving processing of a recording operation mechanism, and the like. I do. The recording head 2 is driven under the control of the recording control unit 1, and performs recording by discharging ink onto recording paper.

The clock section 3 is configured as a clock counter that counts clock pulses and measures elapsed time, for example, and may use a normal timer circuit, clock circuit, or the like. In this case, the timer 3 measures at least the elapsed time after the end of the recording operation, that is, the idle time.

The recovery device 4 includes a cleaning unit 14 to be described later, and sucks and forcibly discharges ink from the ejection holes of the recording head 2, that is, the ink nozzle portion, to recover the function of the recording head 2.

The discharge control unit 5 controls the recovery device 4 to forcibly discharge ink from the recording head 2. The temperature sensor 6 detects the temperature inside the recording head 2 and gives it to the discharge control unit 5.

The discharge control section 5 includes a reference value holding section 51, a comparison section 52, and a weight correction section 53. The reference value holding unit 51 holds a set time value of an elapsed time from the end of recording to the time when forced ejection is performed, that is, a leaving time, that is, a reference value. The setting time of the reference value of the leaving time for forced discharge held in the reference value holding unit 51 is, for example, 260 × 10
^It may be set to ³ seconds, and can be changed and set as desired. The comparing unit 52 compares the count value of the idle time measured by the timer unit 3 with the reference value held in the reference value holding unit 51. Basically, the count value of the idle time reaches the reference value. Then, the recovery device 4 is driven to forcibly discharge the ink. The weight correction unit 53 multiplies at least one of the idle time and the reference time set by the comparison unit 52 by a weighting coefficient based on the temperature information in the print head at the end of printing provided from the temperature sensor 6. Then, the leaving time for the forcible discharge is corrected. The weight correction unit 53 multiplies, for example, the time count value by a weighting coefficient corresponding to the temperature information. Specifically, the weight correction unit 53 obtains a weight coefficient according to the temperature detected by the temperature sensor 6 at the end of recording using a table set and stored in advance, and causes the comparison unit 52 to act on the weight coefficient. Note that the weight correction unit 53 may use an arithmetic expression for obtaining a weighting coefficient from the detected temperature, instead of using a table.

FIG. 2 shows, in addition to the recording head 2, a platen 11, a guide shaft 12, a carriage 13, a cleaning unit 14, a control device 15, and a recording sheet P.

The platen 11 places a recording sheet P as a recording material on the upper surface. The recording paper P is recorded on the platen 11 by the recording head 2 and is driven and conveyed to move on the platen 11.

Above the platen 11, for example, two mutually parallel guide shafts 12 are installed in parallel with the platen 11. A carriage 13 is attached to the guide shaft 12 via a slide bearing (not shown) so as to be reciprocally movable, so that the carriage 13 can be moved in parallel along the guide shaft 12. The recording head 2 that ejects ink is mounted on the carriage 13. The carriage 13 is operated by a motor and a belt (both not shown) in accordance with the control of the recording control unit 1, and can reciprocate the mounted recording head 2 in parallel with the guide shaft 12.

At a retracted position outside the image forming area at one end of the movable range of the carriage 13, there is provided a cleaning unit 14 for performing cleaning by forcibly discharging the recording head 2 by suctioning ink. The cleaning unit 14 is a part of the recovery device 4.

The control device 15 includes the recording control unit 1 and the discharge control unit 5, and controls the operation of the ink jet plotter.

The cleaning unit 14 shown in FIG.
A cap 21, a suction cylinder 22, a pump 23, a waste ink discharge pipe 24, and a waste ink container 25 are provided. FIG. 3 also shows the recording head 2.

The recording head 2 contains ink therein,
This ink is ejected from the nozzle 2a to perform recording. At the time of recording, for example, nozzle 2
The ink at the nozzle 2a is heated and discharged by a heating element (not shown) provided at the portion a. The recording operation of the recording head 2 is controlled by the recording control unit 1. A temperature sensor 6 is provided near the nozzle 2a inside the recording head 2.

The cap 21 is made of a flexible material such as rubber, and has an opening 21a and an ink discharge 21b. The cap 21 forms an airtight space between the recording head 2 and the cap 21 by bringing the opening 21a into close contact with the recording head 2 so as to cover the surface of the nozzle 2a.

The suction cylinder 22 has an ink suction port 22.
a, a pump port 22b, a discharge port 22c, and check valves 22d and 22e. The ink suction port 22a is fitted to the ink discharge portion 21b of the cap 21 to hold the cap 21, and forms a suction path for sucking ink.
The pump port 22b fits and connects the pump 23. The discharge port 22c forms a discharge path for discharging ink. The check valves 22d and 22e prevent backflow of the sucked ink when sucking the ink.

The pump 23 has a piston 23a, is connected to a pump port 22b of the suction cylinder 22, and reciprocates the piston 23a in a direction indicated by an arrow A by a pump driving mechanism (not shown). A negative pressure is generated in 22.

The waste ink discharge pipe 24 is flexible and has one end connected to the suction cylinder 22 and the other end provided with the ink discharge end 24 a positioned above the waste ink container 25.

The portion consisting of the cap 21, the suction cylinder 22, the pump 23 and the waste ink discharge pipe 24 is moved in the vertical direction, that is, in the direction of arrow B in the figure, by a suction unit driving mechanism (not shown) such as a solenoid. Can be.

The output of the temperature sensor 6 incorporated in the recording head 2 is transmitted to the discharge control unit 5 through an appropriate transmission line such as a lead wire.

When the ink is forcibly discharged, the recording head 2
Is moved to the evacuation position, and in a state where it is located directly above the cap 21, the portion including the cap 21, the suction cylinder 22, the pump 23, and the waste ink discharge pipe 24
The cap opening portion 21a is moved upward in the drawing along the direction of the arrow B in the drawing by the suction unit drive mechanism to press the cap opening 21a against the nozzle 2a of the recording head 2. The ink is sucked from the recording head 2 by generating a negative pressure by moving the piston 23a of the pump 23 in the direction of arrow A to the left in the figure. The sucked waste ink is used as cap 2
1 or once in the suction cylinder 22. Then, the part consisting of the cap 21, the suction cylinder 22, the pump 23, and the waste ink discharge pipe 24 is integrally moved downward in the direction of the arrow B in the figure to move the cap 2
1 is separated from the recording head 2. The piston 23a
By reciprocating several times in the direction of arrow A, the waste ink retained in the cap 21 and the suction cylinder 22 is discharged. The discharged waste ink passes through a waste ink discharge pipe 24 and is discharged to a waste ink container 25 from a discharge end 24a.

Next, the flow of the operation in the ink jet plotter configured as described above will be specifically described with reference to FIG.

When the power of the ink jet plotter is turned on for the first time, the operation shown in FIG. 4 is started.

First, the counting of the idle time of the idle time counter of the timer 3 is started (step S11).
Next, it is determined whether or not there is a recording command (step S12).
If the recording command is given, the counting of the idle time counter is stopped, and the count value data at that time is suspended (step S13). The recording head 2 performs recording by discharging ink onto a recording paper P as a recording medium on the platen 11 while reciprocating on the platen 11 under the control of the recording control unit 1. 6 detects the head temperature accompanying the recording. In this state, the process waits for the end of the print command (step S14). When the print command ends, the discharge control unit 5 takes in the temperature information inside the print head 2 by the temperature sensor 6 (step S1).
5) A weighting coefficient corresponding to the head temperature is determined (step S16).

The relationship between the head temperature and the weighting coefficient is as follows.
For example, as shown in FIG.

That is, when the head temperature is lower than 30 ° C., the weighting factor is 0.9, and when the head temperature is higher than 30 ° C. and lower than 40 ° C., the weighting factor is 1.0, and the weighting factor is higher than 40 ° C. and 50 ° C.
When it is less than 1.1, the weighting factor is 1.1
When the temperature is lower than 0 ° C., the weighting factor is 1.2, and when the temperature is 60 ° C. or higher, the weighting factor is 1.3.

When the weighting coefficient is determined, the counting of the idle time by the idle time counter is restarted (step S17). Hereafter, the count value of the idle time is the following: hold data + subsequent count value x weighting coefficient.

During the counting of the idle time, the presence or absence of a recording command is checked (step S18). If there is no recording command, it is checked whether or not the time is less than a set time (step S19). If it is determined in step S19 that the time is less than the set time, the process returns to step S18 again, and
The determination of step S18 and step S19 is repeated. If it is determined in step S19 that the power is not less than the set time, that is, it is determined that the set time has been reached, it is checked whether the power is on (step S20). Is performed (step S21), and the count value of the idle time counter is cleared (step S22). If it is determined in step S20 that the power is not on, the forced ink discharge and the counter clear are performed after the power is turned on. In addition, this forced ink discharge operation is not performed immediately when the idle time reaches the set time, but it is not performed immediately.
The recording operation may be performed before the start of the recording operation when the recording start signal is supplied again.

If it is determined in step S12 that there is no recording command, it is determined whether the time is less than the set time (step S23).
Returning to step S12, if the set time has been reached, the process proceeds to step S20.

If it is determined in step S18 that a recording command has been given, the process returns to step S13.

When the count value is cleared in step S22, the flow returns to step S11, and the above processing is repeated.
If the idle time during which recording is not performed is prolonged even after forced ink discharge, bubbles grow, so the time is counted again and the forced discharge operation is performed. For example, when the power is once turned on and forced discharge is performed after leaving the apparatus, but the power is turned off again without recording and the apparatus is left for a long time, the forced discharge is naturally required. In this case, weighting based on the state at the end of recording is unnecessary.

In this manner, forced ink discharge can be performed in accordance with the degree of air bubble generation due to the temperature rise in the print head during printing, and wasteful consumption of ink and defective printed images can be prevented. .

[Second Embodiment] An ink-jet plotter according to a second embodiment of the present invention will be described with reference to FIGS.

FIG. 6 schematically shows a functional configuration of an ink jet plotter according to the second embodiment of the present invention, and FIG. 7 shows a flowchart of the operation.

The ink jet plotter shown in FIG.
A recording control unit 1, a recording head 2, a timing unit 3,
A recovery device 4 and a discharge control unit 5 are provided, and a dot number counter 7 is provided instead of the temperature sensor 6.

The dot number counter 7 counts the number of ink ejections since the last forcible discharge operation, that is, the number of recording dots.

In this case, the weight correction section 53 of the discharge control section 5
Is obtained by multiplying at least one of the idle time and the reference value setting time, which are the inputs of the comparison unit 52, by a weighting coefficient based on the count value at the end of printing provided by the dot number counter 7, that is, the number of printing dots. The leaving time for the forced discharge is corrected. Weight correction unit 53
Multiplies the time count value of the time counting unit 3 by a weighting coefficient corresponding to the count value, for example. Specifically, the weight correction unit 53 obtains a weighting coefficient corresponding to the count value of the dot number counter 7 at the end of recording using a table set and stored in advance, and compares the weighting coefficient with the comparison unit 52.
To act on. Note that the weight correction unit 53 may use an arithmetic expression for obtaining a weighting coefficient from the count value, instead of using the table.

Next, the flow of operation in the ink jet plotter configured as described above will be specifically described with reference to FIG.

When the power of the ink jet plotter is turned on for the first time, the operation shown in FIG. 7 is started.

First, the counting of the idle time of the idle time counter of the timer unit 3 is started (step S31).
Next, the presence or absence of a recording command is determined (step S32),
If the recording instruction has been given, the counting of the idle time counter is stopped, and the count value data at that time is suspended (step S33). Under the control of the recording control unit 1, the recording head 2 ejects ink onto recording paper P, which is a recording medium, on the platen 11 while reciprocating on the platen 11, and performs recording. Based on the operation of the control unit 1, the number of times of ink ejection during recording, that is, the number of recording dots since the previous forced ink discharging operation is integrated and counted. In this state, the process waits for the end of the print command (step S34). When the print command ends, the discharge control unit 5 captures the integrated count value of the dot counter 7 (step S35), and assigns a weighting coefficient corresponding to the number of print dots. It is determined (step S36).

The relationship between the number of recording dots and the weighting coefficient is, for example, as shown in FIG.

[0070] That is, the number of recording dots, 6 × 10 ⁷ weighting factor when weighting coefficients and less than 8 × 10 ⁷ dots 0.6,6 × 10 ⁷ pixels or when less than dots 0.7,8 × When the number is 10 ⁷ dots or more and less than 10 × 10 ⁷ dots, the weighting coefficient is 0.8. When the weight is 10 × 10 ⁷ dots or more and less than 12 × 10 ⁷ dots, the weighting coefficient is 0.9, 12 × 10 ⁷ dots or more. In this case, the weighting coefficient is set to 1.0.

When the weighting coefficient is determined, the counting of the idle time by the idle time counter is restarted (step S37). Hereafter, the count value of the idle time is the following: hold data + subsequent count value x weighting coefficient.

During the counting of the idle time, the presence or absence of a recording command is checked (step S38). If there is no recording command, it is checked whether or not the time is less than a set time (step S39). If it is determined in step S39 that the time is less than the set time, the process returns to step S38 again.
The determination in steps S38 and S39 is repeated. If it is determined in step S39 that it is not less than the set time, that is, it is determined that the set time has been reached, it is checked whether the power is on (step S40). Is performed (step S41), and the count value of the idle time counter is cleared (step S42). If it is determined in step S40 that the power is not on, the forced ink discharge and the counter clear are performed after the power is turned on. In addition, this forced ink discharge operation is not performed immediately when the idle time reaches the set time, but it is not performed immediately.
The recording operation may be performed before the start of the recording operation when the recording start signal is supplied again.

If it is determined in step S32 that there is no recording command, it is determined whether the time is less than the set time (step S43).
Returning to step S32, if the set time has been reached, the process proceeds to step S40.

If it is determined in step S38 that a recording command has been given, the process returns to step S33.

When the count value is cleared in step S42, the flow returns to step S31, and the above processing is repeated.
If the idle time during which recording is not performed is prolonged even after forced ink discharge, bubbles grow, so the time is counted again and the forced discharge operation is performed. For example, when the power is once turned on and forced discharge is performed after leaving the apparatus, but the power is turned off again without recording and the apparatus is left for a long time, the forced discharge is naturally required. In this case, weighting based on the state at the end of recording is unnecessary.

Also in this case, it is possible to forcibly discharge ink in accordance with the degree of bubble generation based on ink discharge in the print head accompanying printing, thereby preventing wasteful consumption of ink and defective printed images. Can be.

[Third Embodiment] An ink jet plotter according to a third embodiment of the present invention will be described with reference to FIGS.

FIG. 9 schematically shows a functional configuration of an ink-jet plotter according to the third embodiment of the present invention, and FIGS. 10 and 11 show flowcharts of the operation.

The ink jet plotter shown in FIG.
A recording control unit 1, a recording head 2, a timing unit 3,
The apparatus includes a recovery device 4 and a discharge control unit 5, and further includes an environmental temperature sensor 8 instead of the temperature sensor 6.

The environmental temperature sensor 8 is provided, for example, in the vicinity of a portion of the ink jet plotter which is in contact with the outside air, for example, at the end of the platen 11, or the like. Detect temperature.

In this case, the weight correction section 53 of the discharge control section 5
Is obtained by multiplying at least one of the idle time and the reference time set by the comparing unit 52 by a weighting coefficient based on the environmental temperature given from the environmental temperature sensor 8 to obtain the idle time for forced discharge. Is corrected. The weight correction unit 53 multiplies, for example, the idle time count value by a weighting coefficient corresponding to the environmental temperature. Specifically, the weight correction unit 53 obtains a weighting coefficient corresponding to the environmental temperature using a table set and stored in advance, and causes the comparing unit 52 to act on the weighting coefficient. The weight correction unit 53
In, instead of using a table, an arithmetic expression for obtaining a weighting coefficient from the environmental temperature may be used.

Next, the flow of operation in the ink jet plotter configured as described above will be described with reference to FIGS.
This will be specifically described with reference to FIG.

When the power of the ink jet plotter is turned on for the first time, the operation shown in FIG. 10 is started.

First, the counting of the idle time of the idle time counter of the timer section 3 is started (step S51).
Next, the presence or absence of a recording command is determined (step S52).
If the recording command has been given, the counting of the idle time counter is stopped, and the count value data at that time is suspended (step S53). The recording head 2 performs recording by discharging ink onto a recording paper P as a recording medium on the platen 11 while reciprocating on the platen 11 under the control of the recording control unit 1. In this state, the process waits for the end of the recording command (step S54). When the recording command ends, counting of the idle time by the idle time counter is restarted (step S55). Hereafter, the count value of the idle time shall be the hold data + the count value after.

During the counting of the idle time, the presence or absence of a recording command is checked (step S56). If there is no recording command, it is checked whether or not the time is less than a set time (step S57). If it is determined in step S57 that the time is less than the set time, the process returns to step S56 again, and
The determinations in step S56 and step S57 are repeated. If it is determined in step S57 that it is not less than the set time, that is, it is determined that the set time has been reached, it is checked whether the power is on (step S58). Is performed (step S59), and the count value of the idle time counter is cleared (step S60). If it is determined in step S58 that the power is not on, the forced ink discharge and the counter clear are performed after the power is turned on. In addition, this forced ink discharge operation is not performed immediately when the idle time reaches the set time, but it is not performed immediately.
The recording operation may be performed before the start of the recording operation when the recording start signal is supplied again.

If it is determined in step S52 that there is no recording command, it is determined whether the time is less than the set time (step S61).
Returning to step S52, if the set time has been reached, the process proceeds to step S58.

If it is determined in step S56 that a recording command has been given, the process returns to step S53.

When the count value is cleared in step S60, the process returns to step S51, and the above processing is repeated.
If the idle time during which recording is not performed is prolonged even after forced ink discharge, bubbles grow, so the time is counted again and the forced discharge operation is performed. For example, when the power is once turned on and forced discharge is performed after leaving the apparatus, but the power is turned off again without recording and the apparatus is left for a long time, the forced discharge is naturally required. Also in this case, it is necessary to perform weighting based on the state.

On the other hand, the routine for measuring the environmental temperature is shown in FIG.
In parallel with the routine of FIG.

First, with the counting of the idle time (step S71), after a predetermined time has elapsed (step S7).
2) The ambient temperature is measured (Step S73). When the environmental temperature is measured, a weighting factor is determined (Step S74).

The relationship between the environmental temperature and the weighting coefficient is, for example, as shown in FIG.

That is, when the environmental temperature is lower than 15 ° C., the weighting factor is 0.8. When the environmental temperature is higher than 15 ° C. and lower than 20 ° C., the weighting factor is 0.9. When the environmental temperature is higher than 20 ° C. and lower than 25 ° C., the weighting factor is higher. Is 1.0, 25 ° C. or higher and 30
When the temperature is lower than 30 ° C., the weighting factor is 1.1, and when the temperature is 30 ° C. or higher, the weighting factor is 1.2.

When the weighting coefficient is determined, the count of the idle time by the idle time counter is changed (step S).
75). Hereafter, the count value of the idle time is the following: hold data + subsequent count value x weighting coefficient.

After changing the count value in step S75, the process returns to step S71, and the above-described processing is repeated.

In this manner, forced ink discharge can be performed in accordance with the degree of air bubble generation due to the ambient temperature of the outside air, and wasteful consumption of ink and defective printed images can be prevented.

[Fourth Embodiment] An ink jet plotter according to a fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 13 schematically shows a functional configuration of an ink jet plotter according to a fourth embodiment of the present invention.
14 and 15 show flowcharts of the operation.

The ink-jet plotter shown in FIG. 13 includes a recording control unit 1, a recording head 2, a timing unit 3, a recovery device 4, and a discharge control unit 5 similar to those in FIG. The air pressure sensor 9 is provided.

The atmospheric pressure sensor 9 is, for example, a part in contact with the outside air of the ink jet plotter, for example, the platen 11.
And detects the external pressure, that is, the atmospheric pressure in the environment where the inkjet plotter is installed, always or during the idle time.

In this case, the weight correction section 53 of the discharge control section 5
Is based on the atmospheric pressure given from the atmospheric pressure sensor 9,
A weighting coefficient is multiplied by at least one of the idle time and the set time of the reference value, which are input to the comparing unit 52, to correct the idle time for forced discharge. Weight correction unit 5
3 multiplies the idle time count value by a weighting coefficient corresponding to the atmospheric pressure, for example. Specifically, the weight correction unit 53 obtains a weighting coefficient corresponding to the atmospheric pressure using a table set and stored in advance, and causes the comparison unit 52 to act on the weighting coefficient. In the weight correction unit 53,
Instead of using a table, an arithmetic expression for obtaining a weighting coefficient from the atmospheric pressure may be used.

Next, FIG. 14 and FIG. 1 show the operation flow of the ink jet plotter configured as described above.
This will be specifically described with reference to FIG.

The operation shown in FIG. 14 is started when the power of the ink jet plotter is first turned on.

First, the counting of the idle time of the idle time counter of the timer section 3 is started (step S81).
Next, it is determined whether there is a recording command (step S82).
If the recording command has been given, the counting of the idle time counter is stopped, and the count value data at that time is suspended (step S83). The recording head 2 performs recording by discharging ink onto a recording paper P as a recording medium on the platen 11 while reciprocating on the platen 11 under the control of the recording control unit 1. In this state, the end of the recording command is waited for (Step S84). When the recording command is completed, the counting of the idle time by the idle time counter is restarted (Step S85). Hereafter, the count value of the idle time shall be the hold data + the count value after.

During the counting of the idle time, the presence or absence of a recording command is checked (step S86). If there is no recording command, it is checked whether or not the time is less than the set time (step S87). If it is determined in step S87 that the time is less than the set time, the process returns to step S86 again,
The determination in steps S86 and S87 is repeated. If it is determined in step S87 that the power is not shorter than the set time, that is, it is determined that the set time has been reached, it is checked whether the power is on (step S88). Is performed (step S89), and the count value of the idle time counter is cleared (step S90). If it is determined in step S88 that the power is not on, the forced ink discharge and the counter clear are performed after the power is turned on. In addition, this forced ink discharge operation is not performed immediately when the idle time reaches the set time, but is not performed immediately.
The recording operation may be performed before the start of the recording operation when the recording start signal is supplied again.

If it is determined in step S82 that there is no recording command, it is determined whether the time is less than the set time (step S91).
Returning to step S82, if the set time has been reached, the process proceeds to step S88.

If it is determined in step S86 that a recording command has been given, the process returns to step S83.

When the count value is cleared in step S90, the flow returns to step S81, and the above processing is repeated.
If the idle time during which recording is not performed is prolonged even after forced ink discharge, bubbles grow, so the time is counted again and the forced discharge operation is performed. For example, when the power is once turned on and forced discharge is performed after leaving the apparatus, but the power is turned off again without recording and the apparatus is left for a long time, the forced discharge is naturally required. Also in this case, it is necessary to perform weighting based on the state.

On the other hand, the atmospheric pressure measurement routine operates as shown in FIG. 15 in parallel with the routine of FIG.

First, with the counting of the idle time (step S101), the elapse of a predetermined time is waited (step S1).
02), the atmospheric pressure is measured (step S103). When the atmospheric pressure is measured, a weighting coefficient is determined (Step S104).

The relationship between the environmental temperature and the weighting coefficient is, for example, as shown in FIG.

That is, when the atmospheric pressure is less than 0.6 atm, the weighting coefficient is 0.8,
When it is less than tm, the weighting coefficient is 0.9, 0.8atm or more and when it is less than 1.0 atm, the weighting coefficient is 1.0, 1.
When the value is 0 atm or more and less than 1.1 atm, the weighting coefficient is 1.1, and when it is 1.1 atm or more, the weighting coefficient is 1.2.

When the weighting coefficient is determined, the count of the idle time by the idle time counter is changed (step S).
105). Hereafter, the count value of the idle time is the following: hold data + subsequent count value x weighting coefficient.

After changing the count value in step S105, the process returns to step S101, and the above-described processing is repeated.

In this way, forced ink discharge can be performed in accordance with the degree of bubble generation due to atmospheric pressure, and wasteful consumption of ink and defective printed images can be prevented.

In each of the above-described embodiments, the printhead temperature at the end of printing, the total number of printed dots at the end of printing, the environmental temperature, and the weighting factor according to the atmospheric pressure are set under conditions close to normal standard conditions. Is set as the standard weighting coefficient 1.0, but other conditions may be weighted with the standard weighting coefficient 1.0.

In each embodiment, the timing of the forced discharge operation is corrected in accordance with the print head temperature at the end of printing, the total number of print dots at the end of printing, the ambient temperature, and the atmospheric pressure. However, these two or more can be combined as appropriate. In such a case, if the standard weighting factor is set to 1.0, a comprehensive correction that addresses various factors can be realized by multiplying the weighting factors by each other.

Note that the total number of dots, numerical values of weights for correction, and the like shown in the above-described embodiments are merely examples, and do not limit the present invention. Further, the correction method is not limited to the weighting using the reference table, and an appropriate correction method such as using a function of a measured or detected value for correction can be applied.

The present invention can be applied not only to the plotter but also to an ink jet printer, a copying machine, a facsimile machine and the like in the same manner as described above.

[0119]

As described above, in the ink jet recording apparatus according to the present invention, at least one of the elapsed time and a predetermined value serving as a comparison reference is corrected in accordance with the condition of leaving, and the ejection is forcibly performed after the recording is completed. The time interval until the operation is properly adjusted to perform the forced discharge operation. With such control, the change in the degree to which the dissolved gas becomes bubbles based on the temperature of the recording head at the end of recording, and the outside air from the sealing material based on the amount of gas in the head accompanying the print amount until the end of recording. Conditions such as a change in the degree of mixing, a change in the degree to which dissolved gas becomes bubbles based on a temperature change during standing, and a change in the degree of outside air mixed into the head based on a change in atmospheric pressure during standing were considered. An appropriate forced discharge operation is performed in an appropriate leaving time. Therefore, the ink is not wastefully discharged by the forced discharge operation, and the occurrence of a defective recorded image due to bubbles can be prevented.

That is, according to the ink jet recording apparatus of the present invention, the forced discharge operation can be performed at an appropriate timing in accordance with the condition of the idle state, and wasteful consumption of ink and defective printed images can be effectively prevented. An ink jet recording apparatus capable of preventing the above problem can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an inkjet plotter according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a partial configuration of the plotter of FIG.

FIG. 3 is a schematic sectional view showing another configuration of another part of the plotter of FIG. 1;

FIG. 4 is a flowchart for explaining the operation of the plotter of FIG. 1;

FIG. 5 is a diagram for explaining weighting variables for explaining the operation of the plotter in FIG. 1;

FIG. 6 is a block diagram illustrating a configuration of an inkjet plotter according to a second embodiment of the present invention.

FIG. 7 is a flowchart for explaining the operation of the plotter in FIG. 6;

FIG. 8 is a diagram for explaining weighting variables for explaining the operation of the plotter of FIG. 6;

FIG. 9 is a block diagram illustrating a configuration of an inkjet plotter according to a third embodiment of the present invention.

FIG. 10 is a first flowchart for explaining the operation of the plotter in FIG. 9;

FIG. 11 is a second flowchart for explaining the operation of the plotter in FIG. 9;

FIG. 12 is a diagram for explaining weighting variables for explaining the operation of the plotter in FIG. 9;

FIG. 13 is a block diagram illustrating a configuration of an inkjet plotter according to a fourth embodiment of the present invention.

FIG. 14 is a first flowchart for explaining the operation of the plotter in FIG. 13;

FIG. 15 is a second flowchart for explaining the operation of the plotter in FIG. 13;

FIG. 16 is a diagram for explaining weighting variables for explaining the operation of the plotter in FIG. 13;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording control part, 2 ... Recording head, 3 ... Clock part, 4 ... Recovery device, 5 ... Discharge control part, 6 ... Temperature sensor, 7 ... Dot number counter, 8 ... Environmental temperature sensor, 9 ... Atmospheric pressure sensor,
11: platen, 12: guide shaft, 13: carriage, 14: cleaning unit, 15: control device,
21: cap, 22: suction cylinder, 23: pump,
24: waste ink discharge pipe, 25: waste ink container,
51: Reference value holding unit, 52: Comparison unit, 53: Weight correction unit

Claims (10)

[Claims] A recording head having an ejection hole for ejecting ink from the ejection hole to perform recording; a recovery unit for forcibly discharging ink in at least the ejection hole of the recording head; Time detecting means for detecting an elapsed time from the forced ejection operation of the recording head; a temperature detecting means for detecting at least a temperature inside the recording head at the end of the last recording; an elapsed time detected by the time detecting means and a predetermined value When the elapsed time exceeds a predetermined value, the recovery unit performs a forced ejection operation, and the elapsed time and the temperature of the recording head at the end of recording detected by the temperature detecting unit. Control means for correcting at least one of the predetermined values and controlling a time interval from the end of the recording to the forced discharge operation by the recovery means. Ink jet recording apparatus characterized by. 2. The apparatus according to claim 1, further comprising a counting unit that counts the number of times of ink ejection from a previous forcible ejection operation by the recovery unit to the end of the last printing, and wherein the control unit calculates the number of ejections by the counting unit. 2. The ink jet recording apparatus according to claim 1, further comprising means for correcting at least one of an elapsed time and a predetermined value. 3. An image forming apparatus according to claim 1, further comprising: an environmental temperature detecting unit configured to detect an environmental temperature around the recording head for at least a predetermined period after the end of the last recording. 3. The ink jet recording apparatus according to claim 1, further comprising means for correcting at least one of an elapsed time and a predetermined value. 4. At least a pressure detecting means for detecting a pressure around the recording head at least for a predetermined period after the end of the last recording, and the control means controls an elapsed time and an air pressure according to the pressure detected by the pressure detecting means. The inkjet recording apparatus according to claim 1, further comprising a unit that corrects at least one of the predetermined values. 5. A recording head having an ejection hole and performing recording by intermittently ejecting ink from the ejection hole, a recovery unit for forcibly discharging ink in at least the ejection hole of the recording head, and the recovery. Time detecting means for detecting the time elapsed from the previous forced discharging operation by the means; counting means for counting the number of ink discharges from the previous forced discharging operation by the recovery means to the end of the last recording; and The elapsed time detected by the means is compared with a predetermined value, and when the elapsed time exceeds the predetermined value, the recovery means is caused to perform a forced discharge operation, and the elapsed time is calculated according to the count value of the number of ejections by the counting means. And control means for correcting at least one of the predetermined value and adjusting the time interval from the end of the recording to the forced discharge operation by the recovery means. An ink jet recording apparatus according to claim and. 6. A recording head having an ejection hole and performing recording by ejecting ink from the ejection hole, a recovery unit for forcibly discharging ink in at least the ejection hole of the recording head, and a previous operation performed by the recovery unit. Time detecting means for detecting an elapsed time from the forced discharge operation, an environmental temperature detecting means for detecting an environmental temperature around the recording head at least for a predetermined period after the end of the last recording, and the time detecting means. The elapsed time is compared with a predetermined value, and when the elapsed time exceeds a predetermined value, the recovery means is caused to perform a forced discharge operation, and the elapsed time and the predetermined value are determined according to the environmental temperature detected by the environmental temperature detecting means. Control means for correcting at least one of the above and adjusting the time interval from the end of the recording to the forced discharge operation by the recovery means. An ink jet recording apparatus according to claim and. 7. The ink jet recording apparatus according to claim 6, wherein the environmental temperature detecting means includes means for detecting at least one of the temperature inside and outside the ink jet recording apparatus. 8. A recording head having an ejection hole and performing recording by ejecting ink from the ejection hole, recovery means for forcibly discharging ink in at least the ejection hole of the recording head, Time detecting means for detecting an elapsed time from the forced discharge operation of the above, pressure detecting means for detecting the atmospheric pressure around the recording head at least for a predetermined period after the end of the last recording, and elapsed time detected by the time detecting means And a predetermined value, and when the elapsed time exceeds a predetermined value, the recovery means performs a forced discharge operation, and determines at least one of the elapsed time and the predetermined value according to the atmospheric pressure detected by the air pressure detecting means. And control means for performing control for adjusting the time interval from the end of recording to the forced discharge operation by the recovery means. Ink jet recording apparatus. 9. The ink jet recording apparatus according to claim 8, wherein the air pressure detecting means includes a means for detecting at least one of an external pressure and an internal pressure of the ink jet recording apparatus. 10. The apparatus according to claim 1, wherein the control means includes means for making a correction by applying a weighting factor based on a standard state to at least one of an elapsed time to be compared and a predetermined value. 2. The ink jet recording apparatus according to claim 1.