JPH11138851A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder with a head failure control means that does not produce poor discharge even if a pigment ink that does not disperse or melt again after dried and solidified, is used. SOLUTION: The recorder has a head failure control means that operates an ink-end program when the relationship among the amount of ink M that is used in maintenance including the movement of ink, the amount of ink P that is used for printing several sheets, the residual amount of ink Z, the critical amount of ink PMax that can print, the critical amount of ink MMax that allows maintenance and the amount of ink error z for detection of a residual amount, satisfies PMax-MMax>P, if Z<=MMax+M+▵z is satisfied or when it satisfies PMax-MMax<=P, if Z<=PMax+M+P+▵z is satisfied.

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 forming an ink image on a recording medium such as recording paper by flying ink droplets, and more particularly to a head down preventing means.

[0002]

2. Description of the Related Art An ink jet recording apparatus directs ink from a plurality of nozzle openings of an ink jet head, a droplet diameter,
This is a recording apparatus capable of obtaining good printing quality by discharging while keeping the discharge speed constant. Further, since the number of ejection ports and the type of ink can be easily increased in the ink jet recording apparatus, color recording has progressed and the ink jet recording apparatus has become a mainstream recording apparatus at present. For this reason, the number of nozzles per ink jet recording apparatus also tends to increase, reaching 80 to 100 holes or more. However, on the other hand, there is a disadvantage that a nozzle surface having a number of nozzle openings for discharging ink becomes dirty, and if one of the nozzle openings becomes entangled, a discharge failure occurs and good printing cannot be performed. The reason why good printing is not possible is that clogging due to drying of the ink around the nozzle opening or in the flow path, etc., or that the amount of ink stored for printing decreases and the ink required for ejection cannot be supplied sufficiently. is there.

[0003] The ink can be roughly classified into a dye ink in which all components of the ink are constituted by a dye having resolubility, and the like.
There is a pigment ink using a pigment which is dispersed without being dissolved as a colorant in the ink. Dye inks are excellent in resolubility, and once dried and solid, the ink dissolves and returns to liquid when it comes in contact with fresh ink again. Once the pigment ink is dried and solidified, it re-disperses or re-dissolves even if it touches the fresh ink again because the pigment particles aggregate and the polymer for fixing the pigment component on the recording paper becomes insoluble. Do not wake up. That is, in the case of the pigment ink, unlike the dye ink, when the ink attached to the wall surface is dried, it is not possible to remove the stain caused by the attached ink by flowing the ink. However, compared to dyes, pigments have better light fastness and do not dissolve, so it is necessary to preserve the printing results for a long period of time or to have water resistance, such as for printing mailing addresses. When it is necessary to obtain a print result for the above, it is necessary to perform printing using a pigment ink.

[0004] As a means for recovering a discharge failure such as clogging, an ink jet recording apparatus is provided with a maintenance station. In order to recover the clogging caused by drying of the ink, all the components of the ink are composed of a re-soluble dye, etc. However, if such a method is adopted, there is a problem that it is not possible to obtain water resistance and light resistance of a printed result. The role of the maintenance station is to clean the nozzle surface of the inkjet head, the inside of the nozzle opening, and the flow path due to ink drying due to various factors such as during printing and long-term storage. It has a function of cleaning and recovering the discharge state to a good state by a method of washing away by dissolving so that good printing can be performed.

As means for returning to a good ejection state by using a re-soluble ink, Japanese Patent Publication No. Hei 3-430 is used.
For example, as shown in FIG.
There has been proposed a method of suppressing backflow by releasing the ink to the atmosphere while sucking ink as in 795. Generally, a wiper is brought into contact with the discharge port surface of an ink jet head and the wiper and the discharge port surface are moved relatively to each other. Wiping means for removing ink adhering to the surface, a suction port connected to a suction pump or the like, and a cap having an air communication port equipped with a valve for communicating with the atmosphere covers the discharge port and forcibly sucks. Thus, suction recovery means for re-dissolving the dry ink clogged in the discharge port with fresh ink again, making the solid liquid again, and recovering by discharging the liquid to the outside of the discharge port is combined.

[0006] In such a conventional ink jet recording apparatus, it is possible to clean the nozzle surface or the like due to the drying of the water-resistant and re-soluble ink. In the case of using an ink containing non-hazardous pigments and high molecular components, simply performing maintenance will not allow cleaning of the ink-stained parts that do not re-dissolve by flowing fresh ink again. However, good printing cannot be permanently obtained, or the ink jet recording apparatus itself may be broken in some cases.

[0007] Therefore, in order to solve the above-mentioned problems, the present applicant has proposed an inkjet head having a nozzle port on at least a nozzle surface for discharging ink, a pigment ink using a pigment as a colorant, and A drive waveform generating circuit for discharging ink from the nozzle openings of the inkjet head, a timer for measuring the time from the start of the discharge, and at least the ink absorber is brought into contact with the nozzle surface of the inkjet head to clean the nozzle surface. A nozzle surface cleaning device that moves the ink absorber and the nozzle surface relative to each other after absorbing the absorbed ink, a maintenance station including an ink moving device for discharging ink from the nozzles, and printing is completed. Print end button to detect that the printing An ink jet recording apparatus equipped with a software power switch for detecting, before the time from the start of ejection reaches the time until the pigment ink attached to the nozzle surface dries, at least the nozzle surface is cleaned, and printing is completed. A head protection means has been proposed in which a button signal is detected, a signal from a software power switch is detected, and at least the nozzle surface is cleaned when ink is discharged from a nozzle by an ink moving device.

On the other hand, if the amount of ink stored for printing is reduced and the ink required for ejection cannot be supplied sufficiently, it is detected that the re-soluble ink has no remaining amount of ink. It suffices if printing is not performed and the stored ink is exhausted. When the ink for printing is not supplied, the ink that should have been filled from the tank storing the ink to the discharge port for discharging the ink is exhausted, the atmosphere is full, The remaining ink is on the wall of the road. If left in this state, the ink remaining on the wall surface is dried, and the dried ink adheres. When ink with resolubility is used, even in such a state, by flowing fresh ink through the flow path again, it is necessary to remove dirt from the flow path and restore it to the initial state before drying. Can be. However, in the case of a pigment ink in which the dried and solidified ink cannot be removed with fresh ink, the solidified ink remains in the flow path, so that the performance of the head is significantly reduced or the head is broken.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides an ink jet recording apparatus having a head down preventing means which does not cause a discharge failure even when a pigment ink which does not disperse or dissolve again even after being dried and solidified. It is in.

[0010]

In order to solve the above problems, an ink jet head having a nozzle opening at least on a nozzle surface for discharging ink, a pigment ink using a pigment as a coloring agent, and an ink jet head A drive waveform generating circuit for discharging from a nozzle opening of the head, an ink tank for storing ink, a remaining amount detecting unit for detecting the remaining amount of ink, at least a nozzle surface cleaning device, and ink from the nozzle. An ink jet recording apparatus comprising: an ink moving device for discharging ink; and a maintenance station including an ink evaporation preventing unit for preventing ink from evaporating from a nozzle, wherein an ink amount used in a maintenance operation including ink movement is provided. Printing with M, ink amount P and ink remaining amount Z used to print several sheets Can the amount of ink remaining in the limit PMax
And the remaining ink level M at which maintenance can be performed
The relationship between Max and the ink error amount △ z of the remaining amount detection is expressed by PM
When ax-MMax> P is satisfied, Z ≦ MMax +
When M + △ z is satisfied, or PMax−MMax ≦
If Z ≦ PMax + M + P + △ z is satisfied when P is satisfied, the ink end program of the head-down prevention unit performs printing within the ink amount P, then moves the ink with the ink moving device, and moves the ink with the nozzle surface cleaning device. Clean the nozzle surface, prevent ink evaporation by ink evaporation prevention means, and then use the ink or evaporate ink other than the signal to recover the stored amount of ink and the signal to turn off the power. Either stop receiving the command to cause, or after the ink end program of the head down prevention unit performs printing within the ink amount P, move the ink with the ink moving device, perform idle discharge, and perform the nozzle surface cleaning device. Clean the nozzle surface, prevent ink evaporation by ink evaporation prevention means, and then recover the stored amount of ink. Other than the signal for cutting issue and a power supply,
Activate an ink end program that does not accept a command that causes the phenomenon of using or evaporating the ink, or the ink amount M used in the maintenance operation and the ink amount P used for printing several sheets and the ink remaining amount. The relationship between the amount Z, the remaining ink amount PMax at which printing can be performed, the remaining ink amount MMax at which maintenance can be performed, and the ink error amount △ z of remaining amount detection satisfies Z ≦ PMax + P + △ z. If the ink amount P
After printing, the nozzle surface is cleaned by the nozzle surface cleaning device, the ink evaporation prevention means is used to prevent ink evaporation, and then the signal for restoring the stored amount of ink and the signal for turning off the power Other than the above, a command that causes a phenomenon of using or evaporating ink is not accepted, or after performing printing within the ink amount P, performing idle discharge, cleaning the nozzle surface with the nozzle surface cleaning device, Ink evaporation is prevented by the ink evaporation preventing means, and thereafter, commands other than a signal for restoring the stored amount of ink and a signal for turning off the power, which do not accept a command that causes a phenomenon of using or evaporating ink, other than a signal for turning off the power. Or, after printing within the ink amount P, the nozzle surface is cleaned by the nozzle surface cleaning device, idle discharge is performed, and the ink After that, operate the ink end program to stop receiving commands that cause the phenomenon of using or evaporating ink, other than the signal for recovering the stored amount of ink and the signal for turning off the power. If it is detected that the remaining amount of ink has already reached the set amount before turning on the power and printing,
Ink evaporation is prevented by the ink evaporation preventing means, and thereafter, commands other than a signal for restoring the stored amount of ink and a signal for turning off the power, which do not accept a command that causes a phenomenon of using or evaporating ink, other than a signal for turning off the power. The problem can be solved by providing the inkjet recording apparatus with a head down prevention unit for operating the ink end program. That is, in the ink jet recording apparatus according to the first aspect, an ink jet head having a nozzle port on at least a nozzle surface for discharging ink, a pigment ink using a pigment as a colorant, and discharging the ink from the nozzle port of the ink jet head A drive waveform generating circuit, an ink tank for storing ink, a remaining amount detecting unit for detecting the remaining amount of ink, at least a nozzle surface cleaning device, and an ink for discharging ink from the nozzle. An ink jet recording apparatus comprising: a moving device; and a maintenance station including an ink evaporation preventing unit for preventing ink from evaporating from a nozzle, wherein an ink amount M used in a maintenance operation including ink movement and several sheets of printing are recorded. It is possible to print with the ink amount P and the ink remaining amount Z used for printing. Relationship between the ink error amount △ z ink levels MMax remaining amount detection limits that can perform ink remaining amount PMax and maintenance limit, PMax-MM
If Z ≦ MMax + M + △ z is satisfied when ax> P is satisfied, or Z ≦ PMax + M + P + △ z is satisfied when PMax−MMax ≦ P is satisfied.
A head down prevention unit for operating an ink end program is provided. In the ink jet recording apparatus according to the second aspect, after the ink end program of the head down prevention means performs printing within the ink amount P,
Move the ink with the ink moving device, clean the nozzle surface with the nozzle surface cleaning device, prevent the ink from evaporating by the ink evaporation preventing means, and then turn off the signal and power to recover the stored amount of ink. It is characterized in that a command other than a signal that causes a phenomenon of using or evaporating ink is not accepted. In the ink jet recording apparatus according to the third aspect, after the ink end program of the head down prevention means performs printing within the ink amount P,
The ink moving device moves the ink, performs idle discharge, cleans the nozzle surface with the nozzle surface cleaning device, prevents the ink from evaporating by the ink evaporating prevention means, and thereafter outputs a signal for recovering the stored amount of the ink. It is characterized in that a command other than a signal for turning off the power, which causes a phenomenon of using or evaporating ink, is not accepted. In the ink jet recording apparatus according to the fourth aspect, an ink jet head having a nozzle port on at least a nozzle surface for discharging ink, a pigment ink using a pigment as a colorant, and discharging the ink from the nozzle port of the ink jet head Drive waveform generating circuit, an ink tank for storing ink, a remaining amount detecting means for detecting the remaining amount of ink, at least a nozzle surface cleaning device, and an ink moving device for discharging ink from the nozzles An ink jet recording apparatus comprising: a maintenance station comprising: an ink evaporation preventing unit for preventing ink from evaporating from a nozzle; an ink amount M used in a maintenance operation; and an ink used for printing several sheets. Quantity P
And the remaining amount of ink Z, the remaining amount of ink PMax at which printing can be performed, the remaining amount of ink MMax at which maintenance can be performed, and the ink error amount △ z of remaining amount detection, Z ≦ PMax + P + △ When z is satisfied, a head down prevention means for operating an ink end program is provided. In the ink jet recording apparatus according to the fifth aspect, the ink end program of the head down prevention unit performs printing within the ink amount P, then cleans the nozzle surface with the nozzle surface cleaning device, and prevents ink evaporation by the ink evaporation prevention unit. Thereafter, other than a signal for restoring the stored amount of ink and a signal for turning off the power, a command that causes a phenomenon of using or evaporating the ink is not accepted. In the ink jet recording apparatus according to the sixth aspect, the ink end program of the head down prevention means performs idle discharge after printing within the ink amount P, and cleans the nozzle surface with the nozzle surface cleaning device. In this way, the ink is prevented from evaporating, and thereafter, other than the signal for restoring the stored amount of ink and the signal for turning off the power, a command that causes a phenomenon of using or evaporating the ink is not accepted. I do. In the ink jet recording apparatus according to the seventh aspect, after the ink end program of the head down prevention unit performs printing within the ink amount P, the nozzle surface cleaning unit cleans the nozzle surface, performs idle discharge, and performs the ink evaporation prevention unit. In this way, the ink is prevented from evaporating, and thereafter, other than the signal for restoring the stored amount of ink and the signal for turning off the power, a command that causes a phenomenon of using or evaporating the ink is not accepted. I do.
In the ink jet recording apparatus according to the eighth aspect, when the ink end program of the head down prevention unit detects that the remaining amount of ink has already reached the set amount before the power is turned on and printing is performed, the ink evaporation prevention unit is used. In this way, the ink is prevented from evaporating, and thereafter, other than the signal for restoring the stored amount of ink and the signal for turning off the power, a command that causes a phenomenon of using or evaporating the ink is not accepted. I do.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following configuration.

(Embodiment) A head down preventing means of the present invention will be described. If the ink is not supplied enough due to the low remaining amount of ink between the tank storing the pigment ink and the nozzle opening for discharging the ink, the pigment ink remaining on the wall of the flow path Solidifies as soon as it dries, impairing the function of the inkjet head. Since the pigment is not soluble in water, it is necessary to use an ink using a pigment as a coloring material in order to obtain a printing result requiring water resistance. In order to require complete water resistance for the printing result, a resin for fixing the pigment to the recording paper is required. As a method of adding the resin, when dispersing the pigment in the liquid, a polymer that does not dissolve in water once dried in the dispersant is used, or the resin having a fixing function is dispersed in the ink as an emulsion. There are methods.
The pigments in the ink are configured so that they do not agglomerate due to Van der Waals forces or the like, but when the liquid component in the ink evaporates, the pigment particles adhere to each other to form a large mass. This mass has the property that it does not redisperse when the liquid component is simply given again. As described above, since the pigment ink contains components that are not dissolved again after drying once or components that are not redispersed, once dried and solidified, the pigment ink cannot be removed by dispersion or dissolution.

In order to perform printing with an ink jet head, it is necessary to inject ink into a flow channel without fail. At this time, if air bubbles or the like are mixed in the flow path, the gas mixed in the liquid acts as an elastic body,
When ejecting the ink, the desired pressure cannot be sufficiently transmitted to the ink, causing non-ejection, or bubbles blocking the ink flow path, making it impossible to supply the ink for ejection. For this reason, in the inkjet recording apparatus,
The main part from the tank storing the ink to the nozzle opening for discharging the ink is subjected to a hydrophilic treatment. When the hydrophilization treatment is performed, the contact angle between the ink and the flow path is reduced, so that the wettability is increased, and there is a characteristic that the ink easily flows in the flow path. In addition, since the air bubbles are less likely to adhere to the wall surface of the flow channel due to the change in the surface hydrophilicity, it is easier to remove the ink when moving the ink from the tank direction toward the nozzle opening. However, with insufficient ink supply,
If ink is used and air is mixed into the flow path, conversely if air is mixed into the flow path of ink, more ink will be left. The probability of head down also increases. Therefore, in the case where such an ink that cannot be redissolved or redispersed once dried is used, a head down prevention means for maintaining a state in which the ink is filled in the flow path is required.

As a tank for storing ink, there is a method of filling a porous body or felt with ink, storing ink in a container, or using these at the same time. The stored ink cannot use all of the injected ink. This is particularly noticeable when a fibrous ink holder such as a porous body or felt is used. When the ink is sufficiently filled in the porous or felt fibrous ink holding member, the supply pressure is low and the supply speed is high, but the amount of the ink is about 30% of the injection amount. As the supply pressure increases, the supply speed also decreases. Further, when the remaining amount of ink decreases, it becomes impossible to supply ink required for printing gradually, and a discharge failure occurs. The supply speed required for the ink tank when performing maintenance including the process of discharging ink from the nozzle orifice using the ink moving device is 10 times or more higher than the supply speed when performing printing. When the ink supply speed is insufficient and the ink is ejected from the nozzle orifice using the ink moving device, the air becomes bubble-like with the ink and flows into the flow path. Since the drying of the ink is started by the flowing air, the head goes down. Therefore, maintenance is already disabled before printing becomes impossible.

As a method of detecting the remaining amount of ink, a method of measuring the ink supply pressure, a method of calculating from the total number of ink droplets ejected and the amount of suction, a method of utilizing a change in volume, and the like are used. be able to.

In the head down prevention means of the present invention, the state in which the pigment ink in the flow path is always filled is maintained. This will be described with reference to FIG. FIG. 1 shows the remaining amount of ink on the horizontal axis, where the amount of ink stored in the ink tank is 100. The limit ink amount that can perform maintenance operations including ink movement
ax. This point indicates that the ink discharge speed when the ink moving device is operated is equal to the ink supply speed from the ink tank. The maximum ink amount at which ink can be ejected is shown as PMax. This point indicates that the ink use speed required for printing is equal to the ink supply speed from the ink tank. The amount of ink used in the maintenance operation including one ink movement is represented by a line segment M, and the amount of ink required to print several sheets is represented by a line segment P. Next, the timing at which the ink end program is executed will be described. The condition is set so that a large amount of the remaining amount of Δz is left. In the case where the operation of discharging the ink from the nozzle port is not included in the ink end program during the ink end program, the ink end program is executed when the remaining amount of ink reaches PMax + P + △ z. In the case where the ink end program includes an operation of discharging the ink from the nozzle orifice during the ink end program, and the relation between the respective ink amounts satisfies PMax−MMax> P, the remaining amount of ink is MMax + M + When Δz is reached, the ink end program is executed. Also, the relationship between the respective ink amounts is PMax-M
When Max ≦ P is satisfied, the remaining amount of ink
When ax + P + M + △ z is reached, an ink end program is executed.

The ink end program mounted on the circuit board will be described with reference to FIGS. FIG. 2 shows the skeleton of the ink end program of the head down prevention means of the present invention. The remaining amount of the ink reaches the set amount by grasping the remaining amount. At this point, the ink end program is executed. In the ink end program, an ink end is displayed to notify the user that the ink stored in the ink jet recording apparatus has run out.
Subsequently, if printing is in progress, printing of the current data is continued within the unit amount. If printing is not being performed, ink end maintenance is performed. The unit amount is one page if the recording paper is cut sheet, and if the recording paper is continuous paper such as roll paper,
Set the unit length for the print output length. If the printing is completed at this time, the ink end maintenance is performed. If the printing is not completed at this time, the ink amount P left for performing the printing and the ink end program are being executed. It is determined whether or not the difference between the ink amounts used for one or more units remains. When the difference is less than one unit amount, ink end maintenance is performed. If the difference is equal to or more than one unit amount, printing is continued within the printing range of one unit amount, and it is confirmed whether printing is completed by confirming the presence or absence of print data. If the printing is completed, the ink end maintenance is performed. If the printing is not completed, the difference between the ink amount P left for printing and the ink amount used during the execution of the ink end program is 1 again. It is repeatedly determined whether or not a unit amount or more remains and whether to perform printing or execute ink end maintenance is repeated. The amount of ink to be left for printing is set on the assumption that the entire surface is printed at full duty. In the case of cut sheet paper, when one page is set as a unit amount, about 5 to 8 pages are preferable. In the case of continuous paper, the unit is length, but 5c
It is preferable to set the length from m to about 30 cm.
The length direction can be reset to the number of rows according to the inkjet head. Of course, even in the case of cut-sheet paper, the unit amount may be the length or the number of lines as in the case of continuous paper. Since the relationship between the unit amount and the amount of ink P left for printing varies depending on the application, it is preferable that the relationship can be changed according to the purpose of use. Ink end maintenance is
There are cases where ink is discharged from the nozzle orifices using the ink moving means, and cases where ink movement is not included. The choice between the two is that the remaining amount of ink is PMax + P
When the ink end program is executed when + △ z is reached, the ink end maintenance does not include the ink movement. In other cases, ink end maintenance including ink movement is selected. The ink end maintenance will be described with reference to FIGS. 3 to 5 show the ink end maintenance not including the ink movement, and FIGS. 6 and 7 show the ink end maintenance including the ink movement. The ink end maintenance shown in FIGS. 3 to 7 selectively performs operations of cleaning the nozzle surface, idle discharge, and ink movement, and shows the order in which these operations are performed. After performing the ink end maintenance, the pigment ink is not attached to the nozzle surface in any case. After performing the ink end maintenance, evaporation prevention is performed so that the ink in the nozzles does not dry. In this state, among the signals for operating the inkjet recording apparatus, a signal using ink is not accepted. The accepted signal is
A signal for refilling ink and a signal for turning off the power. Turn off the power when you receive the power off signal from the power switch. When receiving a signal to refill the ink, it prepares for replenishment of the ink and waits for the replenishment of the ink. In order not to prevent it from evaporating. The setting of the constant waiting time must be set to the time during which a failure occurs due to drying of the ink from the nozzles.
It is desirable to set the time to about 0 to 60 seconds.
The determination as to whether or not ink has been replenished can be detected by remaining amount detection. When the ink is replenished, a maintenance operation is performed so that good printing is obtained, the ink end display is canceled, and the ink end program is ended. FIG. 8 shows an ink end program when it is detected that the remaining amount of ink is small when the power is turned on. As soon as it is detected that the remaining amount of ink is less than the set value, an ink end display is performed to prevent evaporation.
In this state, among the signals for operating the inkjet recording apparatus, a signal using ink is not accepted. The received signals are a signal for replenishing the ink and a signal for turning off the power. Turn off the power when you receive the power off signal from the power switch.
When receiving a signal to refill the ink, it prepares for replenishment of the ink and waits for the replenishment of the ink.If the replenishment is not performed within a certain period of time, the inkjet recording device may be damaged due to evaporation or the like. In order not to prevent it from evaporating. The fixed waiting time must be set to a time during which a failure occurs due to drying of the ink from the nozzles, but is desirably set to a time of about 30 to 60 seconds. The determination as to whether or not ink has been replenished can be detected by remaining amount detection. When the ink is replenished, a maintenance operation is performed so as to obtain good printing, the ink end display is canceled, and the ink end program is ended. In addition, if it is displayed that the ink end is approaching before the ink remaining amount for starting the ink end program is reached, the user can
Ready for when the ink end is reached,
Easy to use.

An ink moving device for discharging ink from the nozzle includes a suction device that covers the nozzle provided on the nozzle surface using a cap, and depressurizes the inside of the cap to suction and discharge ink. Any type of pressurizing device can be used, which presses ink out of the nozzles to discharge unnecessary ink. As a nozzle surface cleaning device for removing ink on the nozzle surface, a nozzle surface cleaning member in which an elastic base is attached to a holder serving as a support and the surface of the elastic body is covered with a sheet-like ink absorbing member is used. did. As the base elastic body, a porous body such as rubber or sponge or a fiber entangled with felt or the like can be used. In this embodiment, rubber is used. As the ink absorbing member, polyester and nylon were used. The ink absorbing member is made to be able to expose a new surface when the ink is absorbed and becomes dirty. As an operation, the nozzle surface cleaned with ink and the nozzle surface cleaning member are moved to the opposite position. Next, by bringing the nozzle surface cleaning member into contact with the nozzle surface, the ink penetrates the ink absorbing member and the ink on the nozzle surface is moved to the nozzle surface cleaning member side. The contact pressure was set to a pressure at which the ink absorbing member was brought into close contact with the nozzle surface. The contact was maintained while the ink on the nozzle surface moved to the ink absorbing member.
Next, since there is a case where ink that cannot be absorbed by the ink absorber remains, the nozzle surface cleaning member and the nozzle surface are removed by relatively moving. The number of operations of moving the nozzle surface cleaning member and the nozzle surface in relative contact with each other was performed twice. Thus, the nozzle surface was cleaned.
As the ink evaporation preventing means for preventing the drying of the ink,
Made caps and seals.

FIG. 9 is a schematic diagram of an ink jet recording apparatus embodying the present invention. In FIG. 9, reference numeral 1 denotes a carriage, which is an inkjet head 2 having a nozzle surface subjected to a water-repellent treatment.
, An ink tank 4, a relay member 5 for connecting the ink jet head 2 to the ink tank 4, and a circuit board 7. The circuit board 7 has a power switch, a timer for measuring the time until ink is filled, a circuit for executing an ink end program, and the like. Further, it has a remaining amount detecting means (not shown). The inkjet head 2 has a plurality of ejection ports for ejecting inks of different colors. A carriage motor (not shown) drives the carriage 1 via the timing belt 8 and reciprocates left and right along the guide rail 9 in the figure. The FPC 30 connects a drive circuit (not shown) to the circuit board 7. On the other hand, a paper feed motor (not shown) drives the paper feed roller 31 and the paper discharge roller 12, pulls out the recording paper 32 onto the platen 14, and moves the recording paper 32 in a direction perpendicular to the moving direction of the carriage. In this manner, while moving the carriage 1 and the recording paper 32, the positions of the respective heads 2 on the recording paper 32 are two-dimensionally changed, and the ink is supplied from the heads 2 according to a recording signal by a known means such as piezoelectric driving. , The recording pattern such as an image and a character can be recorded on the recording paper 32. A nozzle surface cleaning means 18 for removing dirt on the nozzle surface of the ink jet head, an ink moving means 21 for removing unnecessary ink and air bubbles in the nozzle, and a nozzle surface having a plurality of nozzles beside the printing area. Is provided with an evaporation preventing means 33 including a cap, a seal member, and the like for preventing the ink from drying by covering the ink. In the ink jet recording apparatus of this embodiment, an ink moving device capable of discharging ink by suctioning with a cap is provided. At least phthalocyanine as a colorant as an ink, azo-based,
A water-based pigment ink was used in which a pigment such as perylene or carbon black was dispersed in water, and 0 to 40 parts by weight of a humectant having a moisturizing function such as glycerin, diethylene glycol, or propanediol was added.

(Embodiments 1 to 25) Printing is continuously performed from 0 ° to 60 ° using the ink jet recording apparatus of the present invention, ink is consumed, and FIGS. 2 and 3 to 7 The ink end program shown in FIG. After turning off the power after confirming that printing has stopped. Thereafter, the apparatus was left for one month, turned on again, and it was observed whether or not good printing could be obtained by replenishing the ink. Table 1 shows the results. As a result, good printing could be obtained in any case.

[0021]

[Table 1]

(Comparative Examples 21 to 5) Printing was continuously performed from 0 ° to 60 ° using an ink jet recording apparatus not equipped with the head down prevention means of the present invention, and ink was consumed. Was. The power was turned off after confirming that printing was not possible due to lack of ink. Then 1
After leaving it for a month, the power was turned on again, and it was observed whether good printing could be obtained by refilling the ink. Table 2 shows the results. As a result, the ink remaining in the flow path dries, clogs the nozzles, and printing cannot be obtained.

[0023]

[Table 2]

[0024]

As described above, according to the present invention, it is possible to prevent head-down caused by running out of ink, so that it is possible to use an ink containing a pigment which does not re-dissolve or disperse when dried and solidified. , And the reliability of the ink end was greatly improved because the ink end failure was eliminated.
In addition, since ink containing a pigment can be used, printing with excellent water resistance and light resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a head down prevention unit of the present invention.

FIG. 2 is a diagram for explaining an ink end program of the present invention.

FIG. 3 is a diagram for explaining an ink end program of the present invention.

FIG. 4 is a diagram for explaining an ink end program of the present invention.

FIG. 5 is a diagram for explaining an ink end program of the present invention.

FIG. 6 is a diagram for explaining an ink end program of the present invention.

FIG. 7 is a diagram for explaining an ink end program of the present invention.

FIG. 8 is a diagram for explaining an ink end program of the present invention.

FIG. 9 is a schematic diagram of an ink jet recording apparatus.

[Explanation of symbols]

 Reference Signs List 1 carriage 2 inkjet head 3 head holder 4 ink tank 5 relay member 7 circuit board 8 timing belt 9 guide rail 12 paper discharge roller 14 platen 18 nozzle surface cleaning means 21 ink moving means 30 FPC 31 paper feed roller 32 recording paper 33 evaporation prevention means

Claims (8)

[Claims] 1. An ink jet head having a nozzle port on at least a nozzle surface for discharging ink, a pigment ink using a pigment as a colorant, and a drive waveform generation for discharging the ink from the nozzle port of the ink jet head. A circuit, an ink tank for storing ink,
A remaining amount detecting means for detecting the remaining amount of ink, at least a nozzle surface cleaning device, an ink moving device for discharging ink from the nozzles, and an ink evaporation preventing means for preventing evaporation of ink from the nozzles An ink jet recording apparatus comprising a maintenance station, comprising: an ink amount M used in a maintenance operation including ink movement, an ink amount P used to print several sheets, and an ink remaining amount Z; When the relationship between the maximum remaining amount of ink PMax that can be performed, the maximum remaining amount of ink MMax at which maintenance can be performed, and the amount of ink error △ z for remaining amount detection satisfies PMax−MMax> P, Z ≦ MMax + M + △ z Is satisfied, or when PMax-MMax ≦ P is satisfied. Z ≦ PMax + M + P + △ z is satisfied. An ink jet recording apparatus having a head down prevention means for operating an ink end program. 2. An ink end program of a head down prevention unit, after printing within an ink amount P, moves ink by an ink moving device, cleans a nozzle surface by a nozzle surface cleaning device, and executes an ink evaporation prevention unit. In this way, the ink is prevented from evaporating, and thereafter, other than the signal for restoring the stored amount of ink and the signal for turning off the power, a command that causes a phenomenon of using or evaporating the ink is not accepted. The ink jet recording apparatus according to claim 1, wherein 3. An ink end program of a head-down prevention unit performs printing within an ink amount P, moves ink with an ink moving device, performs idle discharge, and cleans a nozzle surface with a nozzle surface cleaning device. The ink evaporation preventing means prevents the ink from evaporating, and thereafter does not accept any command that causes the phenomenon of using or evaporating the ink other than the signal for recovering the stored amount of ink and the signal for turning off the power. The ink jet recording apparatus according to claim 1, wherein 4. An ink-jet head having a nozzle port on at least a nozzle surface for discharging ink, a pigment ink using a pigment as a colorant, and a drive waveform generation for discharging the ink from the nozzle port of the ink-jet head. A circuit, an ink tank for storing ink,
A remaining amount detecting means for detecting the remaining amount of ink, at least a nozzle surface cleaning device, an ink moving device for discharging ink from the nozzles, and an ink evaporation preventing means for preventing evaporation of ink from the nozzles And an ink amount M used in a maintenance operation, an ink amount P used to print several sheets, a remaining ink amount Z, and a limit ink that can be printed. Head-down prevention means for operating the ink end program when the relationship between the remaining amount PMax and the remaining amount of ink MMax at the limit where maintenance can be performed and the ink error amount △ z for remaining amount detection satisfies Z ≦ PMax + P + △ z. An ink jet recording apparatus comprising: 5. An ink end program of a head down prevention unit performs printing within an ink amount P, cleans a nozzle surface with a nozzle surface cleaning device, prevents ink evaporation with an ink evaporation prevention unit, and thereafter, , Except for the signal to recover the ink storage amount and the signal to turn off the power,
5. The ink jet recording apparatus according to claim 4, wherein a command causing a phenomenon of using ink or evaporating the ink is not accepted. 6. An ink end program of a head down prevention unit performs printing within an ink amount P, performs idle discharge, cleans a nozzle surface with a nozzle surface cleaning device, and controls ink evaporation by an ink evaporation prevention unit. Prevent, then
5. The ink jet recording apparatus according to claim 4, wherein a command that causes a phenomenon of using or evaporating the ink, other than a signal for recovering the stored amount of ink and a signal for turning off the power, is not accepted. 7. An ink end program of a head down prevention unit performs printing within an ink amount P, cleans a nozzle surface with a nozzle surface cleaning device, performs idle discharge, and controls ink evaporation by an ink evaporation prevention unit. Prevent, then
5. The ink jet recording apparatus according to claim 4, wherein a command that causes a phenomenon of using or evaporating the ink, other than a signal for recovering the stored amount of ink and a signal for turning off the power, is not accepted. 8. When the ink end program of the head down prevention means detects that the remaining amount of ink has already reached the set amount before turning on the power and performing printing, the ink evaporation prevention means stops ink evaporation. 2. The method according to claim 1, further comprising: receiving a command that causes a phenomenon of using or evaporating the ink other than a signal for restoring the stored amount of ink and a signal for turning off the power. An ink jet recording apparatus according to any one of claims 1 to 7.