JPH06336024A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To improve a reliability of a printing action by a method wherein a recording head temperature is monitored, a head temperature is estimated from an energy to be inputted to the head and the like, and the non-delivery state of a recording head is judged from these two temperature-related information. CONSTITUTION:An ink jet cartridge 9 formed by integrally providing a delivery device 9a serving as a recording head body and an ink tank 9b is replaceably provided on a carriage. Ink in the ink tank 9b is led into a common ink chamber 902 through a filter 905 and an ink path 904 to be delivered out of delivery ports through a plurality of liquid paths. On a heater head substrate 907, a delivery heater 908 and a head temperature sensor 903 are formed correspondingly to each of the liquid paths. In this invention, the temperature of the recording head is constantly monitored as well as estimated from at least an energy inputted to the head. The non-delivery state of the recording head is judged from the obtained two information.

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 provided with a non-ejection detecting means for an ink jet recording apparatus.

[0002]

2. Description of the Related Art In a recording head of an ink jet recording apparatus, when left for a long time without discharging,
In particular, ink may thicken in the ink liquid passage near the ejection port and normal ejection may not be performed. Further, when ejection is continuously performed, for example, when recording is performed with a relatively high print duty, fine bubbles generated in the ink in the liquid passage due to ejection grow, and the grown bubbles cause the liquid passage to grow. In some cases, the ink may remain inside and affect the ejection, and similarly, the ejection may not be performed normally. In addition to the air bubbles that accompany ejection as described above, there are air bubbles that are mixed in the ink in the ink supply system, such as the connection portion of the ink supply path.

Not only does the reliability of the recording apparatus deteriorate due to the above-mentioned non-ejection, but when a high-duty printing is performed by the recording head in a state where the recording head cannot eject normally, the temperature of the recording head is much higher than that in the normal state. The temperature may rise to damage the recording head itself, and the durability may be impaired.

In the ink jet recording apparatus, for the ejection failure due to these various causes, for example, a capping process for covering the ejection opening surface of the recording head to prevent thickening of the ink when the ejection is not performed, and this capping. In this state, the ink is sucked from the discharge port to discharge the thickened ink, and the thickened ink is discharged to the predetermined ink receiver, which is composed of an ink absorber, in the same way as during normal recording. A discharge recovery process such as empty discharge to be discharged is performed.

Of the above processes, the discharge recovery process is as follows.
For example, it is performed automatically when the apparatus is turned on or at a predetermined time interval during recording operation, or when the user presses a recovery button or the like as necessary.

However, in an ink jet recording apparatus which performs ejection recovery processing when the apparatus is turned on, the number of times the ejection recovery processing is performed unnecessarily increases when used by a user who repeatedly turns the power on and off. Consumption,
There is a problem that the amount of waste ink sucked from the ejection port increases. On the other hand, in the case where the user performs the recovery process by operating the recovery button according to the judgment, the user actually has to print whether the recording head is in a normal state or is not ejecting. There is a problem that the user does not understand and lacks reliability.

In response to this problem, there has been proposed a technique for judging whether or not the print head is not ejected according to a temperature rise in the print head caused by the idle discharge and a temperature drop in the print head after the idle discharge. . That is, when the recording head has no ejection, the temperature difference of the temperature rise and the temperature difference of the sound fall are larger than those when the ejection is performed favorably. Therefore, for example, when the temperature change between the temperature increase and the temperature decrease (for example, the sum thereof) exceeds a predetermined value, it can be determined that ejection failure has occurred in the print head. (Hereafter, this process is called ink drop detection process.) The ink drop detection process is performed when the power is turned on, or every time a fixed period of time has elapsed after the power was turned on. If it is determined that the print head is out of ink, the ejection recovery process is performed. To do. Thereby, it is possible to prevent unnecessary ejection recovery processing, and it is possible to reduce the ink consumption amount and the waste ink amount.

[0008]

The above-mentioned ink jet recording apparatus for performing the ink drop detection processing still has the following problems. Even if the ink drop detection process is performed every time a certain time elapses after the power is turned on, if it is performed unnecessarily, the throughput of the recording apparatus is reduced. If the recording head is in a non-ejection state during printing for some reason and the user does not notice it, the recording device may continue printing operation and damage the recording head due to excessive temperature rise. obtain.

In particular, for example, in an ink jet recording apparatus having a structure in which ink is supplied to a recording head from an ink cartridge and the user replaces the ink with a new ink cartridge when the ink in the ink cartridge is used up, the ink cartridge and the ink supply system Unless the function for detecting that the ink in the ink cartridge is exhausted is not provided, the ink is not supplied to the recording head every time the ink in the ink cartridge is exhausted, resulting in a non-ejection state. Each time, the recording head is exposed to the risk of overheating.

The present invention has been made in view of the above-mentioned problems of the prior art, and constantly or frequently monitors whether the recording head is in a non-ejection state and overheats.
When it is determined that the recording head is in such a state, ejection recovery processing, processing for protecting the recording head, or warning to the user is performed to improve the durability of the head or to improve the reliability of the inkjet recording apparatus. The purpose is to improve.

[0011]

SUMMARY OF THE INVENTION In the present invention, at least head temperature monitoring means for monitoring the temperature of a recording head and head temperature estimation means for estimating the head temperature from energy input to the head, The above object is achieved by additionally having a non-ejection judging means for judging the non-ejection state of the recording head using the information on the two head temperatures.

[0012]

With the above-described means, the presence or absence of excessive temperature rise due to the drive of the recording head in the non-ejection state is constantly or frequently monitored, and when such a state occurs, the ejection recovery process and the recording are performed. Head protection processing, warning to the user, etc. can be performed.

[0013]

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

[1] First, a configuration example of the ink jet recording apparatus used in this embodiment will be described.

FIG. 1 is a diagram showing a configuration example of an embodiment of an ink jet recording apparatus according to the present invention.

In the figure, 9 is a head cartridge having an ink jet recording head which will be described in detail with reference to FIGS.
Reference numeral 11 denotes a carriage for mounting this and operating it in the S direction in the drawing. Reference numeral 13 is a hook for attaching the head cartridge 9 to the carriage 11, and reference numeral 15 is an operation lever for operating the hook 13. This operating lever 15
In addition, a marker 17 is provided for indicating a scale provided on a device cover (not shown) so that the print position and the set position by the recording head of the head cartridge 9 can be read. Reference numeral 19 is a support plate that supports an electrical connection portion for the head cartridge 9. Reference numeral 21 is a flexible cable for connecting the electric connection portion and the main body control portion.

Reference numeral 23 denotes a guide shaft for guiding the carriage 11 in the S direction, and a bearing 25 of the carriage 11
Has been inserted into. 27 is fixed to the carriage 11,
It is a timing belt that transmits the power to move this in the S direction.
It is suspended on 9A and 29B. On one of the pulleys 29B, a carriage motor 31 is passed through a transmission mechanism such as a gear.
More driving force is transmitted.

Reference numeral 33 denotes a conveyance roller that regulates a recording surface of a recording medium such as paper (hereinafter also referred to as recording paper) and conveys the recording surface at the time of recording, and is driven by a conveyance motor 35. Reference numeral 37 denotes a paper pan for guiding the recording medium from the side of the paper feed tray to the recording position, and 39 is provided in the middle of the feeding path of the recording medium and presses the recording medium toward the conveying roller 33 to convey the same. Feed roller. Reference numeral 34 denotes a platen that faces the ejection port forming surface of the head cartridge 9 and regulates the recording surface of the recording medium. Reference numeral 41 is a paper roller arranged downstream of the recording position in the recording medium conveyance direction and for feeding the recording medium toward the paper port when not illustrated.

Reference numeral 42 is a spur provided corresponding to the paper feeding roller 41 and presses the roller 41 via the recording medium to generate a conveying force by the paper feeding roller 41. 43
Is a feed roller 39 for setting a recording medium,
A release lever for releasing the urging force of each of the presser plate 45 and the spur 42.

Reference numeral 45 is a restraint plate for restraining the lift of the recording medium in the vicinity of the recording position and for ensuring a close contact with the conveying roller 33. In this example, an inkjet recording head that performs recording by ejecting ink is used as the recording head. Therefore, the distance between the ink ejection port forming surface of the recording head and the recording surface of the recording medium is relatively small, and the distance must be strictly controlled to avoid contact between the recording medium and the ejection port forming surface. The arrangement of the restraining plate 45 is effective. 47
Is a graduation provided on the pressing plate 45, and 49 is a marker provided on the carriage 11 corresponding to the graduation, by which the printing position and setting position of the recording head can be read.

Reference numeral 51 denotes a cap made of an elastic material such as rubber which faces the ink ejection port forming surface of the recording head at the home position, and is supported so as to be able to come into contact with and separate from the recording head. The cap 51 is used for protection of the recording head during recording, prevention of ink drying, and the above-described ejection recovery process of the recording head. The ejection recovery process is to eject ink from all ejection ports by driving an energy generating element that is provided inside the ink ejection port and is used for ejecting ink, thereby recording bubbles, dust, and viscosity. To remove the cause of ejection failure such as ink that is no longer suitable for the above (the above-mentioned blank ejection), or to separately remove the cause of ejection failure by forcibly ejecting ink from the ejection port by suction (above-mentioned) Ink suction).

Reference numeral 53 denotes a pump which acts as a suction force for forcibly discharging the ink and also for sucking the ink received in the cap 51 during the discharge recovery process by the forced discharge or the discharge recovery process by the idle discharge. . 55 is a waste ink tank for storing the waste ink sucked by the pump 53, and 57 is a tube for connecting the pump 53 and the waste ink tank 55.

Reference numeral 59 denotes a blade for wiping the ejection port forming surface of the recording head. The blade 59 has a position protruding toward the recording head side for wiping in the course of head movement and a retreat that does not engage with the ejection port forming surface. It is movably supported in position and. 61 is a motor, 63 is a motor 61
It is a cam device for driving the pump 53 and moving the cap 51 and the blade 59 by receiving power transmission from the cam device.

Next, details of the above-described head cartridge 9 will be described.

FIG. 2 is an external perspective view of a head cartridge 9 in which an ejection unit 9a forming an ink jet recording head body and an ink tank 9b are integrated, and in FIG. 2, 906e is a carriage 11 when the head cartridge 9 is mounted. It is a pawl that is hooked by a hook 13 provided on the. As is apparent from the figure, the pawl 906e is arranged inside the entire extension of the recording head. In the vicinity of the front ejection unit 9a of the head cartridge 9, there is a head opening portion in which a support plate which is erected on the carriage 11 and which supports a flexible substrate (electrical connection portion) and a rubber pad is inserted.

FIG. 3A is a sectional view of the head cartridge 9 seen from above, FIG. 3B is a front view of the head cartridge 9 seen from the front of the ejection port, and FIG. 3C is a portion showing the structure of the ejection port. FIG.

The recording head used in this embodiment is an electrothermal conversion element (discharge heater) that generates the above thermal energy.
And a substrate made of silicon or the like (hereinafter referred to as HB (heater board)) on which electrode wiring for applying an electric pulse, a driving element, and the like are formed, and which serves as a heat sink that supports the HB, A1 substrate and HB formed by A1
And a top plate that is connected to each of the ejection ports to form an ink liquid path or the like that forms the action portion of the thermal energy.

The head cartridge comprises the ejection unit 9a and the ink tank 9b as described above. The ink in the ink tank 9b is filtered by the filter 905 and the ink passage 90.
4 to the common liquid chamber 902 of the discharge unit 9a. A1 substrate 906 and H constituting the discharge unit 9a
The common liquid chamber 902 is provided on the B substrate 907, and, for example, 64 liquid paths communicating with the common liquid chamber 902 and partition walls for the discharge ports provided in each of the common liquid chambers 902 are provided, thereby forming the discharge port array 901. To be done. A discharge heater 908 is formed on the HB substrate 907 corresponding to each of the liquid paths, and a head temperature sensor 903 is formed on the same HB substrate 907.
Is formed. When viewed from the discharge port surface side, the discharge heater 908, the head temperature sensor 903,
The HB substrate 907 on which wiring and the like are formed is connected,
Further, a top plate 909 is stacked on it to form a discharge port.

[2] Next, the head temperature estimating means used in this embodiment will be described. .

In the present embodiment, the basic equation for estimating the temperature of the recording head conforms to the following general equation for heat conduction.

During heating Δtemp = a {1-exp [-m * T]} (1) Cooling during heating Δtemp = a {exp [-m (T-T ₁ )]-exp [−m * T]} (2) where temp: Temperature rise of object a: Equilibrium temperature of object by heat source T; Elapsed time m; Thermal time constant of object T ₁ ; Time when heat source is removed Recording head If is treated as a lumped constant system, by calculating (1) and (2) above according to the print duty for each thermal time constant,
Theoretically, the chip temperature of the recording head can be estimated.

However, it is generally difficult to perform the above calculation as it is because of the problem of processing speed. -Strictly speaking, all constituent members have different time constants, and time constants occur between members, so the number of calculations becomes enormous.

Generally, the MPU cannot directly perform the exponential calculation, and therefore the calculation time cannot be shortened because it is necessary to perform an approximate calculation or obtain it from a conversion table.

In the present embodiment, the above problem is solved by the following modeling and arithmetic algorithm.

(1) Modeling The inventor applied energy to the recording head having the above structure and sampled the data of the temperature rising process of the recording head, and obtained the results shown in FIG.

Strictly speaking, the recording head having the above structure is composed of a combination of many members having different heat conduction times, but the differential value of the function of the temperature conversion data and the elapsed time obtained by the log conversion is constant. In a certain range (that is, in the range of A, B, and C where the inclination in the above table is constant), it can be practically treated as heat conduction of a single member.

From the above results, in this embodiment, the recording head is treated with two thermal time constants in the model relating to heat conduction. (The above results show that modeling with three thermal time constants enables more accurate regression, but it is judged that the slopes in areas B and C in the table above are approximately equal, and calculation is performed. In this embodiment, the recording head is modeled with two thermal time constants, giving priority to efficiency.)
Specifically, one of the heat conductions is modeled with a time constant that rises to the equilibrium temperature in 0.8 seconds (corresponding to the area A in the table above), and the other one reaches the equilibrium temperature in 512 seconds. It is a model of one having a time constant for increasing the temperature (in the table above, it is a modeling of regions B and C).

Further, in this embodiment, the recording head is treated as follows and modeled.

The temperature distribution during heat conduction is assumed to be negligible, and all are treated in the lumped constant system.

The heat sources are assumed to be heat for printing and heat for the sub-heater.

FIG. 5 shows an equivalent circuit of heat conduction of the recording head modeled in this embodiment.

(2) Calculation Algorithm In the calculation of the head temperature in this embodiment, the above general equation of heat conduction is developed and used as follows.

<EX. Estimating means of temperature after nt time has passed after heat source is turned on>

[0044]

[Equation 1]

As a result of the above expansion, the expression <1> matches <2-1> + <2-2> + <2-3> + ---- + <2-n>. Here, <2-n>expression; equal to the temperature of the object at time nt when heating is performed from time 0 to t and heating is turned off from time t to nt.

<2-3>Expression; when heating is performed from time (n-3) to (n-2) and heating is turned off from time (n-2) to nt,
It is equal to the temperature of the object at time nt.

<2-2>formula; when heating is performed from time (n-2) to (n-1) and heating is turned off from time (n-1) to nt,
It is equal to the temperature of the object at time nt.

<2-1>Equation; Equal to the temperature of the object at time nt when heating from time (n-1) to n.

The fact that the sum of the above equations is equal to the equation <1> means that the temperature behavior of the object 1 (temperature rising temperature) is raised by the energy input per unit time. , How many times the temperature goes down after each unit of time has passed (each <2-1> equation, <2-2> equation --- <2-n> equation), and the current target For the temperature of the object 1, find the sum of how many times the temperature that has risen per unit time in the past is decreasing at the present time (<2-1> + <2-1> + ----- <2-n>) shows that it is possible to estimate by calculation.

From the above, in the present embodiment, the chip temperature of the recording head is calculated four times (heat source 2 * thermal time constant 2) by the above modeling.

The necessary calculation intervals and data holding time for each of the four calculations are as follows.

[0052]

[Table 1]

An operation table for calculating the head temperature, which is a two-dimensional matrix of input energy and elapsed time, is shown in FIGS.

FIG. 6 is a calculation table of heat source; discharge heater, time constant; short range member group, and FIG. 7 is a calculation table of heat source; discharge heater, time constant; long range member group, FIG.
9 is a calculation table of a heat source; sub-heater, time constant; short range member group, and FIG. 9 is a calculation table of heat source; sub-heater, time constant; long range member group.

As shown in the above table, at intervals of 0.05 seconds,
(1) The member of the thermal time constant represented by the short range
How many times the temperature is raised by driving the heater for discharge (△ Tm
h), (2) How many times the temperature of the member having the thermal time constant represented by the short range is raised by driving the sub heater (ΔTs
h), at 1.0 second intervals, (3) How many times the temperature of the member having the thermal time constant typified by the long range is raised by driving the heater for discharging (ΔTmb), (4) Long How many times the temperature of the member with the thermal time constant represented by the range is raised by driving the sub-heater (ΔTsb)?
By adding mh, ΔTsh, ΔTmb, and ΔTsb (= ΔTmh + ΔTsh + ΔTmb + ΔTs
b) The head temperature at that time can be calculated.

As described above, by using the modeling means for substituting the thermal head having a smaller number of thermal time constants than the actual model, the recording head constituted by combining a plurality of members having different heat conduction times is used. As compared with the case where the calculation processing is performed faithfully for all members having different heat conduction times and the thermal time constants between the members, the calculation processing amount can be significantly reduced without significantly lowering the calculation accuracy.

In addition, by modeling with the time constant as the judgment criterion, it becomes possible to perform the arithmetic processing with a small number of times of processing and without degrading the arithmetic accuracy. (For example, in the above example, when modeling is not performed for each time constant, the required calculation processing interval is determined in the area A with a small time constant, and the required calculation interval is 50 msec. Is determined in the B and C regions with a large time constant.
The required data holding time is 2 sec. That is, 50 mse
In the interval c, 10240 data for the past 512 seconds are accumulated and arithmetic processing is performed, which is several hundred times the number of arithmetic processing as compared with the case of the present embodiment. ) As described above, the discrete value stacking calculation means for treating the temperature change of the print head as the stack of discrete values per unit time, and the temperature change of the temperature of the print head according to the discrete value are within the energy range that can be input. A conventional temperature calculation algorithm having an already-calculated table means which has been calculated in advance by means of Table 2 and a two-dimensional table constituting means in which the table is composed of a two-dimensional matrix of input energy per unit time and elapsed time In addition, modeling means for substituting a recording head composed of a plurality of members having different heat conduction times with a thermal time constant smaller than the actual model, and the model unit (thermal time constant) The calculation algorithm means for individually calculating the necessary calculation interval and the necessary data retention time for each, and a plurality of heat sources are set, and the above model is set for each individual heat source. By providing a plurality of heat source calculation algorithm means for calculating the temperature rise by calculating the temperature rise width in units of temperature and adding them together, the temperature sensor is not provided in the print head, and the print head It is possible to perform the arithmetic processing on the entire temperature transition.

[3] Head Temperature Monitoring Means As an example of the head temperature monitoring means, in this embodiment, the head temperature sensor 9 on the HB substrate 907 shown in FIG.
Monitor the head temperature with 03. When the noise level is high, a process for suppressing noise may be performed, such as acquiring the output of the temperature sensor multiple times and averaging the outputs.

[4] Non-ejection judging means In this embodiment, it is judged from the print head temperature and the estimated temperature of the print head by the estimation calculation whether or not the print head is in the non-ejection state. The judgment conditions are shown below.

(Print Head Temperature)-(Estimated Temperature)> ΔTth ΔTth is set to a value large enough not to make an erroneous determination due to a noise signal, and small enough to be determined immediately when ejection failure occurs.

FIG. 10 shows the case where ejection failure occurs during printing.
FIG. 6 is a schematic diagram showing a monitored printhead temperature (average of four times), an estimated calculated value of the temperature of the printhead, and a value obtained by subtracting the estimated calculated value from the printhead temperature. (Less than,
A value obtained by subtracting the estimated calculation value from the printhead temperature is called ΔT. ) ΔT exceeds ΔTth as soon as ejection failure occurs, and it is determined that ejection failure has occurred at that time. Whether or not the ejection is not performed is determined at regular time intervals.

If it is determined that the ejection is defective, the ejection recovery process or the like may be performed immediately. However, in the present embodiment, it may be determined that the ejection is defective due to a sudden noise or the like rarely coming from the outside of the recording apparatus. In consideration of the property, it is determined whether or not the print head is in the non-ejection state by determining the non-ejection of the print head based on the temperature change amount of the temperature increase / decrease of the print head as described above as the conventional technique. Make sure.

This will be described in more detail with reference to FIG. The predetermined time (t ₁ -t ₀₎ temperature rise of the recording head at the time of discharge between (T ₁ -T _0), then the predetermined time (t ₂ -t
₁ ) Temperature decrease of the recording head during non-ejection (T ₁ −
T ₂ ) is detected and the sum of these temperatures (T ₁ −T ₀ ) +
(T ₁ −T ₂ ) = (2T ₁ −T ₀ −T ₂ ) is a predetermined value T _th
If it is above, it is determined that the recording head is in the non-ejection state. A flowchart of the non-ejection determination is shown in FIG. In the present embodiment, as described above, the non-ejection is determined by using both the temperature difference of temperature increase and the temperature difference of temperature decrease. As a result, the ejection failure can be accurately detected even when the temperature of the recording head is slightly decreasing. Only when the temperature change of the recording head is small,
If the ejection failure of the recording head is determined, the determination may be made based on only one of the temperature difference of temperature increase and the temperature difference of temperature decrease.

[5] Ejection Recovery Processing When it is determined that the recording head is in the ejection failure state, suction recovery processing is performed. After that, again, it is determined whether or not the print head is not ejected based on the temperature change amount of the temperature rise / fall of the print head due to the idle ejection, and it is checked whether or not the print head has returned to the normal state. If normal, the ejection recovery process ends. Even if the suction recovery process is performed, if the ejection is not completed, an error is displayed and the user is warned.

In the non-ejection detecting method of this embodiment, when the print duty is low, the temperature rise of the recording head due to printing is naturally small, and it may be impossible to detect the non-ejection. The protection of the recording head from excessive temperature rise due to non-ejection, which is one, can be achieved. In addition, in the third and subsequent embodiments, an embodiment will be introduced in consideration of a case where the print duty is low.

(Second Embodiment) In the second embodiment, .DELTA.Tth used for the non-ejection determination is changed depending on the state of the recording apparatus. The head temperature estimating means and the head temperature monitoring means are the same as those in the first embodiment.

[1] Description of Recording Apparatus Used in Second Embodiment FIG. 12 shows the construction of the recording section of the ink jet recording apparatus used in the second embodiment. In this figure, reference numeral 701 is an ink cartridge. These are 4
It is composed of an ink tank filled with color inks, black, cyan, magenta, and yellow, and a multi-head 702. FIG. 13 shows a state of the multi-nozzles arranged on the multi-head from the z direction, and 801 is a multi-nozzle arranged on the multi-head 702. Return to FIG. 12 again. Numeral 703 is a paper feed roller together with the auxiliary roller of 704 and printing paper P.
While holding down, the printing paper P is rotated in the direction of the arrow in FIG. Further, reference numeral 705 denotes a paper feed roller that feeds printing paper, and like 703 and 704,
It also plays the role of suppressing the printing paper P. Reference numeral 706 is a carriage that supports four ink cartridges and moves them with printing. This is when not printing
Alternatively, when performing a multi-head recovery operation or the like, the home position (h) at the position shown by the dotted line in the figure is waited.

Before the start of printing, the carriage (706) at the position shown in the figure (home position) moves in the x direction when the print start command arrives, and the multi-head (702) moves.
By the above n multi-nozzles (801), printing of width L is performed on the paper surface. When the printing of the data is completed up to the end of the paper, the carriage returns to the original home position and printing is performed again in the x direction. In this way, by repeating the printing of the multi-head width L and the paper feeding for each carriage one scan, the data printing on one paper surface is completed.

However, unlike a printer that prints only characters as a monochrome printer, various elements such as color developability, gradation, and uniformity are required to print an image. Especially regarding uniformity, a slight variation in the nozzle unit that occurs in the multi-head manufacturing process affects the ink ejection amount of each nozzle and the intended ejection direction, and finally the density of the printed image. The unevenness causes deterioration of image quality.

A specific example of the density unevenness will be described with reference to FIGS. 14 and 15 using a single-color recording head for simplification. Figure 1
In 4-a, reference numeral 91 is a multi-head, which is similar to that of FIG. 15, but for simplicity, it is assumed that it is composed of eight multi-nozzles (92).
Reference numeral 93 is an ink droplet ejected by the multi-nozzle 92, and normally, it is ideal that the ejection amount is uniform as shown in FIG. If such ejection is performed, dots of uniform size are landed on the paper surface as shown in FIG. 14-b, and a uniform image without density unevenness is obtained as a whole. . (Fig. 1
4-c) However, in reality, as described above, each nozzle has variations, and if printing is performed in the same manner as above, as shown in FIG. 15-a. The size and direction of the ink drop ejected from each nozzle vary, and as shown in FIG.
It is landed as shown in. According to this figure, there is a blank area that cannot periodically satisfy the area factor 100% with respect to the main operation direction of the head, or conversely, dots are overlapped more than necessary, or they are seen in the center of this figure. Such white streaks occur. The collection of dots landed in such a state has the density distribution shown in FIG. 15-c in the nozzle array direction, and as a result, these phenomena result in density unevenness as seen by human eyes. Is perceived. In addition, streaks due to variations in the paper feed amount may be noticeable.

Therefore, the ink jet recording apparatus used in this embodiment uses the following method. 16,
The method will be briefly described with reference to FIG. According to this method, the multi-head 91 is scanned three times in order to complete the print area shown in FIGS. 14 and 15, but the area in units of 4 pixels is completed in two passes. In this case, the 8 offsets of the multi-head are divided into a group of 4 upper nozzles and 4 lower nozzles, and the dots printed by one nozzle in one scan are specified image data according to a predetermined image data array. It is thinned out to about half. Then, at the time of the second scan, dots are embedded in the remaining half of the image data to complete printing in units of 4 pixels. The recording method described above is read as the divided recording method.

When such a recording method is used, even if the same head as the multi-head shown in FIG. 15 is used, the influence on the print image peculiar to each nozzle is halved, so the printed image is shown in FIG. -B, and the black streaks and white streaks as seen in FIG. 15-b become less noticeable. Therefore, as shown in FIG. 16-c, the density unevenness is considerably reduced as compared with the case of FIG. 15-c.

When such recording is performed, in the first scan and the second scan, the image data is divided in such a manner as to fill each other according to a certain fixed array. Normally, this image data array (thinning pattern) is shown in FIG. As shown in (1), it is common to use a pixel that has a zigzag pattern for each vertical and horizontal pixel. Therefore, in the unit printing area (here, in units of 4 pixels), printing is completed by the first scan for printing the zigzag lattice and the second scan for printing the inverse zigzag lattice. 17-a, 1 in FIG.
7-b and 17-c show how the recording of a certain area is completed when using this zigzag and reverse zigzag pattern, respectively, as in FIGS. It was explained using. First, in the first scan, the staggered pattern is recorded using the lower four nozzles (FIG. 17-a). Next, in the second scan, the paper is fed by 4 pixels (1/2 of the head length). The reverse zigzag pattern is recorded (FIG. 17-b). Further, in the third scan, the paper is fed again by 4 pixels (1/2 of the head tone), and the staggered pattern is recorded again (FIG. 17-c). In this manner, the paper feed in units of 4 pixels and the recording in the staggered and reverse zigzag patterns are alternately performed in this manner, thereby completing the recording area in units of 4 pixels for each scan. As described above, printing is completed by two different types of nozzles in the same area, so that it is possible to obtain a high-quality image without density unevenness.

In the recording apparatus used in the second embodiment, when a graph or the like is printed, printing is performed by the divided recording method which completes printing by the above-described two scans, and printing such as density unevenness such as text is less noticeable. When performing, the printing speed is prioritized and printing is completed with one scan.

[2] Non-ejection determination means In the second embodiment, in the print mode in which printing is completed in two scans, ΔTth is changed to be smaller than in the print mode in which printing is completed in one scan. In addition, by combining the method described above as a conventional technique, which determines whether or not the print head is not ejected based on the temperature change amount caused by the temperature rise caused by the idle ejection and the temperature drop after the idle ejection, To improve the reliability of the recording apparatus with respect to ejection.

In the recording apparatus used in the present embodiment in which a plurality of heads are arranged side by side, when printing is performed with one color head, noise is included in the signals of the head temperature sensors of the other heads. If the print duty is high,
The noise from the signals from the head temperature sensors of other heads is also large. In the print mode in which printing is completed in two scans, the print duty is low and noise is also small. Then, ΔTth can be set to be relatively small. Also, since the print duty is low,
The temperature rise of the recording head accompanying printing also becomes small, and from this point as well, it is necessary to set ΔTth small.

The print duty may be known from the print data prior to the actual printing, and ΔTth may be changed. For example, ΔTth may be reduced when the print duty is low for each line, and ΔTth may be increased when the print duty is high.

In the present embodiment, as an example, ΔTth is changed with respect to the difference in the print duty depending on the print mode. However, it is not only the print duty that influences the noise level and the temperature rise due to printing. For example, ΔTth may be changed depending on other factors such as the recording head drive frequency.

The method of determining whether or not the print head is not ejected based on the amount of temperature change caused by the temperature rise in the print head caused by the idle ejection and the temperature drop after the idle ejection, which is introduced in the prior art, ensures the non-ejection of the print head. Can be determined. But,
Since it can be performed only during non-printing and it takes a long time to execute, there is a drawback that the throughput of the recording apparatus decreases if it is performed frequently. The method of determining the ejection failure of the recording head using the above-described head temperature monitor value and the estimated head temperature value can be executed not only during non-printing, but also has the advantage that throughput is hardly reduced. However, there is a possibility that malfunction may occur due to a sudden noise that is rarely entered from the outside of the printing apparatus, and if the printing duty is low, ΔT is small and it is difficult to determine ejection failure.

Therefore, in this embodiment, the reliability of the recording apparatus against ejection failure is improved by using the two ejection failure determination methods described above together. Specifically, as in the first embodiment, in consideration of the possibility that ejection failure may occur due to a sudden noise that rarely enters from the outside of the printing apparatus, the temperature of the print head is raised or lowered due to idle ejection. The ejection failure of the print head is determined based on the temperature change amount, and it is reliably determined whether the print head is in the ejection failure state.

In addition, when the power of the recording apparatus is turned on, the ejection failure of the recording head is determined by the temperature change amount of the temperature rise / fall of the recording head due to the idle ejection, and if it is determined that the ejection is not performed, the ejection recovery process is performed. In addition, the same sequence is executed when 60 hours have elapsed after the power of the recording apparatus was turned on.

The process flow of the non-ejection detecting means is shown in the flowchart of FIG. In this embodiment, the acquisition of the print mode of the recording apparatus is performed before the ejection failure determination, but it is not an essential configuration. For example, when changing the print mode by the user or application software, ΔT
The th may also be set to be changed to one corresponding to that mode.

In this embodiment, ΔTth is changed according to the print mode of the ink jet recording apparatus, but it is also effective to change ΔTth depending on the states of the recording apparatus other than that.

For example, ΔTth may be changed depending on the thermal condition of the recording head and the difference between the recording head and the ambient temperature.
The distribution of heat in the recording head is different at the start of printing and immediately after printing with high duty for a long time. In the former case, when the discharge is started, the heat generated thereby is quickly transferred to other parts of the head, which have a relatively low temperature as compared with the vicinity of the discharge heater. On the other hand, in the latter case, the parts other than the vicinity of the discharge heater of the recording head are already in a high temperature state, and the heat is relatively hard to be conducted as compared with the former case. From this, in the latter case, it is appropriate to set ΔTth relatively high.

Further, ΔTth may be changed depending on the state of the recording apparatus left unattended. When the recording head is left for a long time, the ink near the ejection port evaporates the volatile component and the viscosity increases, so that the recording head is in a state in which ejection is difficult. The first discharge after leaving for a long time (including preliminary discharge) has a small discharge amount,
Alternatively, it may not be ejected. This situation is
Since T becomes large, it is preferable to set ΔTth large.

Further, ΔTth may be changed depending on the difference between the head temperature monitor value and the head temperature estimated value in a predetermined state of the printing apparatus. For example, since the noise level is low when the recording apparatus does not print for several seconds, the monitor value of the head temperature and the estimated value of the head temperature should originally match. However, if there is a difference between the two temperatures due to the accuracy of the head temperature estimation calculation, etc., the non-ejection detection of the print head is hindered due to the difference between the head temperature monitor value and the estimated head temperature value. Therefore, correcting ΔTth based on the difference is effective for increasing the accuracy of the non-ejection determination. On the contrary, when the recording device is in a predetermined state, even if the estimated value of the head temperature is matched with the monitor value of the head temperature, the same effect can be obtained.

[3] Discharge Recovery Means The discharge recovery means of this embodiment will be described with reference to FIG. If it is determined that the print head is in the non-ejection state, suction recovery processing is performed. After that, again, it is determined whether or not the print head is not ejected based on the temperature change amount of the temperature rise / fall of the print head due to the idle ejection, and it is checked whether or not the print head has returned to the normal state. If normal, the ejection recovery process ends. Even if the suction recovery process is performed, if it is in the non-ejection state,
It judges that there is no ink in the ink tank, displays an error message, and waits for user operation.

Here, when the user replaces the head tank with a tank containing ink and presses the suction recovery key, the suction recovery process and the subsequent non-ejection judgment are performed, and the recording head is in the non-ejection state. Confirm that it is not and return. (The ejection failure flag will be explained later.) If the user presses the ON-LINE key instead of the suction recovery key, the head recovers, but the head judged as ejection failure does not drive. In this embodiment, of the four non-ejection flags corresponding to the four-color heads, the flag corresponding to the head for which non-ejection ejection has been determined is set. Then return. After returning, printing is performed based on the print data, but the head corresponding to the standing non-ejection flag is not driven. Further, control for printing with the head, such as temperature adjustment and preliminary ejection, is not performed. Also, it is assumed that there is no print data corresponding to the color of the head. That is, if there is only print data of that color, scanning of the carriage is not performed.

This processing is for enabling one of the four colors when the ink in the head tank is exhausted, if the user wants to print with only the remaining head. is there. For example, if there is no ink in the head tank of one of cyan, magenta, and yellow among black, cyan, magenta, and yellow,
It is possible to print in black and white with only the black head. If the head that runs out of ink is also driven, excessive temperature rise occurs and the head is damaged. (A head tank having a structure in which the ink tank can be replaced even if the ink is used up is used by replacing the ink tank, and even if it is not, used by refilling the ink.) When the temperature is further raised, the head tank melts. This also adversely affects the recording device body.

In the ink jet recording apparatus of this embodiment, the scanning of the recording area having no data to be printed is controlled as little as possible. Since the head that is determined to be non-ejection does not perform printing, the throughput can be improved by ignoring the print data corresponding to it.

If the non-ejection flag is set when the power of the recording apparatus is turned on or when printing is started, an error message is displayed.
Warn the user. If the user replaces the head tank with ink (or refills with ink), performs suction processing, and if non-ejection is determined by the non-ejection determination after suction, the non-ejection flag is cleared.

The sequence that enables printing with a recording head other than this non-ejection type is not limited to this embodiment,
In an ink jet recording apparatus that ejects a plurality of colors of ink onto a recording material to perform printing, some of the ink ejection apparatuses (in this embodiment, one of the four color recording heads) are in a non-ejection state. Is effective when For example, in a configuration in which one recording head is divided into several parts and they are driven separately (for example, when ink colors are different), it is also effective when only one part thereof is not ejected.

(Third Embodiment) In the third embodiment, as the non-ejection determining means, a value obtained by subtracting the estimated temperature of the head temperature from the head monitor temperature is integrated for a period satisfying a predetermined condition. This embodiment uses the recording apparatus used in the second embodiment, and the head temperature monitoring means, head temperature estimating means, and ejection recovery means are the same as in the first embodiment.

Even when no ejection failure occurs, the head monitor temperature and the head estimated temperature do not match. Causes thereof include, for example, a head temperature estimation calculation, a software timing deviation due to averaging of signals from a head temperature sensor, head temperature estimation accuracy, and various noises. When it is attempted to determine the non-ejection of the recording head with a value obtained by subtracting the estimated value of the head temperature from the head monitor temperature, those become factors that reduce the accuracy of the non-ejection determination.

Therefore, in this embodiment, at fixed time intervals,
Add the value obtained by subtracting the head temperature from the head monitor value. Then, if the value accumulated for a certain period of time is larger than a predetermined threshold value ΔTth, it is determined that the print head is in a non-ejection state. By performing the integration for a certain period of time, it is possible to improve the accuracy of the non-ejection determination, and at the same time, detect the ejection failure even when printing with a lower duty.

In this embodiment, the value obtained by subtracting the estimated temperature of the head temperature from the monitored temperature of the head is integrated. However, due to the accuracy of the estimation calculation and the like, even if the ejection state of the recording head is normal, the head temperature is changed from the monitored temperature of the head. The value obtained by subtracting the estimated temperature may not be 0.
Therefore, it is possible to add a value obtained by performing a predetermined correction on any of the head monitor temperature and the estimated value of the head temperature and then taking the difference. It is also possible to integrate the head monitor temperature and the estimated value of the head temperature, and determine whether or not the recording head is not ejecting based on these values after a certain period of time.

Further, in the present embodiment, the value obtained by subtracting the estimated temperature of the head temperature from the head monitor temperature is integrated for a predetermined time, but the integration time interval is not limited to this, and may be, for example, during one scan. good.

Further, this embodiment includes not only ejection during printing but also ejection during non-printing such as preliminary ejection during printing or before and after printing.

(Fourth Embodiment) In the fourth embodiment, the recording apparatus used in the second embodiment is used, and head temperature monitoring means,
The head temperature estimation means and the ejection recovery means are the same as in the first embodiment.

In the fourth embodiment, the non-ejection detecting means is 1
A value (hereinafter referred to as ΔT) obtained by subtracting the head temperature estimated value from the head monitor temperature is integrated during one scan. Further, the print duty for one scan is known from the print data, and the integrated value is corrected by the value. In this embodiment, as an example, the integrated value is divided by the print duty of one scan to correct the number of characters for each scan and the difference in the print duty. The print duty for one scan is equal to or greater than a predetermined amount (called Dth), and the corrected value is a predetermined threshold value ΔT.
If larger than th, it is determined that the print head is in a non-ejection state.

The print area and duty for printing in one scan are different for each scan. As in the third embodiment, when ΔT is integrated and is not corrected by the print duty and compared with ΔTth, ΔTth has a wide print area for one scan and a wide print duty, that is,
If the integrated value of the print duty for one scan is large, it must be set according to. If ΔTth is set to match when the integrated value of print duty is small, ΔTth becomes relatively small. If the integrated value of print duty for one scan is large in actual printing, the state of the recording head is normal. However, this is because there is a risk that it may be judged as non-ejection.

Therefore, in the present embodiment, correction is made by the integrated value of the print duty over one scan so that the ejection failure can be determined even if the print area during one scan or the print duty is smaller. In this embodiment, as an example, by dividing the integrated value by the print duty of one scan, the number of characters for each scan,
Correct the difference in print duty.

However, when the print area during one scan and the print duty are very small, ΔT is naturally small, and therefore the integrated value of ΔT is also small. In such a case, the value obtained by dividing the integrated value of ΔT by the integrated value of the print duty is greatly influenced by the noise included in the monitor value of the head temperature (the noise level is large). Therefore, there is a high possibility of misjudgment of non-ejection. Therefore, the integrated value of the print duty for one scan is smaller than the predetermined value Dth,
If the noise level is high, it is not judged as non-ejection. The flow of non-ejection determination and ejection recovery is shown in the flowchart of FIG.

With this configuration, the accuracy of detection of non-ejection of the print head is improved more than that of the third embodiment, and non-ejection can be detected even in printing with a lower duty.

In this embodiment, the value obtained by subtracting the head temperature estimated value from the head monitor temperature is corrected by the print duty for one scan, but the threshold value ΔTth for ink drop determination is determined by the print duty for one scan. You may correct it. Further, the period of integration is not limited to one scan. For example, the integration may be performed over 2 scans.

In this embodiment, the value obtained by subtracting the estimated temperature of the head temperature from the monitored temperature of the head is integrated. However, due to the accuracy of the estimation calculation, even if the ejection state of the recording head is normal, the head temperature is changed from the monitored temperature of the head. The value obtained by subtracting the estimated temperature may not be 0.
Therefore, it is possible to add a value obtained by performing a predetermined correction on any of the head monitor temperature and the estimated value of the head temperature and then taking the difference. Further, the head monitor temperature and the estimated value of the head temperature may be integrated, respectively, and it may be determined whether or not the recording head is not ejected based on the integrated values when printing for one scan is completed.

(Fifth Embodiment) In the fifth embodiment, the recording apparatus used in the second embodiment is used, and head temperature monitoring means,
The head temperature estimation means and the ejection recovery means are the same as in the first embodiment.

In the fifth embodiment, the number of print dots is known from the print data prior to actual printing. A value obtained by subtracting the estimated head temperature from the head monitor temperature (hereinafter referred to as ΔT)
At the same time as counting the number of print dots,
When the number of counted dots reaches a certain number, ΔT
Is compared with a predetermined ejection failure determination threshold value ΔTth, and if the integrated value of ΔT is larger, it is determined that the print head is in the ejection failure state.

When the print duty is high, ΔT when the recording head is in the non-ejection state is sufficiently large, and the integration of ΔT for highly accurately determining the non-ejection may be relatively small. When the print duty is low, ΔT is small, and in order to accurately determine ejection failure, ΔT must be accumulated for a long time. In the present embodiment, the number of print dots is counted, and ΔT is integrated until the counted number of dots reaches a predetermined number, so that the print duty is 100% and 50%, for example.
If the print duty is 50%, then 10
ΔT is integrated over twice the number of print dots as in the case of 0%.

With this configuration, the accuracy of detection of non-ejection of the print head can be improved similarly to the third and fourth embodiments, and non-ejection can be detected even in low duty printing.

In this embodiment, the value obtained by subtracting the estimated temperature of the head temperature from the monitored temperature of the head is integrated. However, due to the accuracy of the estimation calculation and the like, even if the ejection state of the print head is normal, the head temperature is changed from the monitored temperature of the head. The value obtained by subtracting the estimated temperature may not be 0.
Therefore, it is possible to add a value obtained by performing a predetermined correction on any of the head monitor temperature and the estimated value of the head temperature and then taking the difference.

Further, when the print duty is relatively low, the integration time is longer than when the print duty is high. Therefore, from the vicinity of the heater of the print head to the other parts of the print head during the integration of ΔT. Also, the amount of heat that flows to the outside also increases. It may be possible that the correction corresponding to these matters is made. For example, if the print duty is relatively low, the integration time increases, and accordingly, the amount of heat that flows out from the vicinity of the heater of the recording head also increases, so if the integration time of ΔT is short, set ΔTth to a small value. Is also good.

Further, the present embodiment may include not only ejection during printing but also ejection during non-printing such as preliminary ejection during printing or before and after printing.

(Sixth Embodiment) In the sixth embodiment, the recording apparatus used in the second embodiment is used, and head temperature monitoring means,
The head temperature estimation means and the ejection recovery means are the same as in the first embodiment.

FIG. 21 is a schematic diagram for explaining the sixth embodiment. In this embodiment, ejection failure determination is performed using the head monitor temperature and the head temperature estimated value immediately after the printing of one scan is completed and immediately before the start of the next scan. In the figure, T1 is the head monitor temperature immediately after the end of printing for one scan, T2 is the estimated head temperature immediately after the end of printing for one scan, T3 is the monitor temperature of the recording head immediately before the start of the next scan, and T4 is the next temperature. This is an estimated value of the head temperature immediately before the start of scanning. The result obtained by subtracting the value obtained by subtracting the estimated head temperature value from the monitor temperature of the head immediately before the start of the next scan is called ΔT from the value obtained by subtracting the estimated head temperature value from the monitor temperature of the head immediately after the printing of one scan. Then, ΔT and a predetermined threshold value ΔTth for non-discharge detection
And if ΔT is larger, it is determined that the print head is in a non-ejection state.

When printing is performed in the state where the ejection failure occurs, the monitor temperature of the head naturally rises higher than the estimated value of the head temperature, but the temperature drop after printing is also the same as the monitor temperature of the head. Since it becomes large, ΔT becomes large. When the ejection state of the print head is normal, the difference between the monitor temperature of the print head and the estimated value of the print head temperature is small, so ΔT is small. The threshold value ΔTth for determination is set large enough to prevent malfunction due to noise or the like and small enough to reliably determine ejection failure.

The merit of this embodiment is that the monitor temperature of the head during non-printing is used. Although not shown in FIG. 21, noise due to printing is included in the signal during printing. It also includes the noise of prints from other parallel heads. In the present embodiment, by removing them, it is possible to determine the ejection failure of the recording head with higher accuracy. In this embodiment, the ejection failure is determined for each scan, but it is also possible to determine the ejection failure of the recording head by integrating ΔT over several scans.

(Seventh Embodiment) In the seventh embodiment, as the non-ejection determining means, a value obtained by subtracting the estimated temperature of the head temperature from the monitor temperature of the head is integrated during the idle ejection performed in the printing state. In this embodiment, the recording apparatus used in the second embodiment is used, and head temperature monitoring means, head temperature estimating means,
The ejection recovery means is the same as in the first embodiment.

In the ink jet recording apparatus of this embodiment, 1
Before the page printing is started, a predetermined number of blank discharges are performed. It is used to determine the ejection failure of the recording head.

Since the blank discharge before the start of printing does not depend on the print duty, there is an advantage that the non-discharge of the recording head can be determined even when the print duty is low. Also, when printing with high duty, non-ejection is detected during printing, and when printing with low duty or continues, the number of blank ejections before page printing is increased to cause print head failure due to blank ejection. It may be configured to determine ejection.

(Eighth Embodiment) In this embodiment, as in the first embodiment, it is determined whether or not the print head is in the non-ejection state based on the monitor temperature of the print head and the estimated temperature of the print head by the estimation calculation. Is determined. The ink jet recording apparatus, head temperature monitor means, head temperature estimation means, and ejection recovery means used in this embodiment are the same as in the first embodiment.

The judgment conditions are shown below.

(Printing Head Temperature)-(Estimated Temperature)> ΔTth In the first embodiment, the empty space is taken into consideration in consideration of the possibility of ejection failure due to a sudden noise that rarely enters from the outside of the printing apparatus. The non-ejection of the print head was determined based on the temperature change amount of the temperature rise / fall of the print head accompanying the ejection, and the non-ejection was finally determined. In this embodiment, the final determination of non-ejection is made by a method in which the printing apparatus optically detects non-ejection of the print head in non-printing.

Specifically, for example, light of a light emitting diode is passed through a portion that receives a droplet of ink ejected from a recording head by blank ejection, and light is received by a light receiving element. Then, at the time of blank ejection, the ejection of ink is determined by detecting that the ink droplet blocks the light of the light emitting diode.

This method is higher in cost than the first embodiment, but can accurately detect even when only a part of the recording head is not ejected, and the ejection direction of the ink droplet ejected from the recording head is deviated. You can also detect the presence.

[0126]

As is apparent from the above description, according to the present invention, it is possible to constantly or frequently monitor the occurrence of ejection failure of the recording head and excessive temperature rise. In this case, the ejection recovery process, the process for protecting the recording head, or the warning to the user is performed, so that the durability of the recording head can be improved and the reliability of the inkjet recording apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an ink jet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the cartridge shown in FIG.

3A, 3B, and 3C are a top view, a front view, and a partially enlarged view of the head cartridge shown in FIG.

FIG. 4 is a schematic diagram of the temperature rise characteristics of the print head in the print head temperature estimation calculation of the first embodiment.

FIG. 5 is an equivalent circuit of heat conduction of a modeled print head in the print head temperature estimation calculation of the first embodiment.

FIG. 6 is a calculation table of an ejection heater and a short range member group in a printhead temperature estimation calculation in the first embodiment.

FIG. 7 is a calculation table of a discharge heater and a long-range member group in the printhead temperature estimation calculation in the first embodiment.

FIG. 8 is a calculation table of a sub-heater and a short range member group in a print head temperature estimation calculation in the first embodiment.

FIG. 9 is a calculation table of a sub-heater and a long-range member group in the printhead temperature estimation calculation in the first embodiment.

FIG. 10 is a schematic diagram for explaining non-ejection determining means in the first embodiment.

FIG. 11 is a schematic diagram for explaining the non-ejection determining means in the first embodiment (No. 2).

FIG. 12 is a flowchart for explaining non-ejection determining means in the first embodiment.

FIG. 13 is a schematic explanatory diagram of an ink jet recording apparatus in a second embodiment.

FIG. 14 is a partial explanatory view of a recording head used in the second embodiment.

FIG. 15 is a diagram showing an ideal printing state in the inkjet recording apparatus.

FIG. 16 is a diagram showing a printing state of an inkjet recording apparatus having uneven density.

FIG. 17 is an explanatory view of reducing uneven density by the divided recording method.

FIG. 18 is an explanatory view (2) of reducing density unevenness by the divided recording method.

FIG. 19 is a flowchart for explaining non-ejection determining means and ejection recovery means in the second embodiment.

FIG. 20 is a flowchart for explaining non-ejection determining means in the fourth embodiment.

FIG. 21 is a schematic diagram for explaining non-ejection determining means in the sixth embodiment.

[Explanation of symbols]

 9 head cartridge 9a ejection unit 9b ink tank 11 carriage 13 hook 15 operation lever 17, 49 marker 19 support plate 23 guide shaft 25 receiving shaft 27 timing belt 29A, 29B pulley 31 carriage motor 33 transport roller 34 platen 35 transport motor 37 paper pan 39 Feed roller 41 Paper roller 42 Spurs 43 Release lever 45 Presser plate 47 Scale 51 Cap 53 Pump 55 Waste ink tank 57 Tube 59 Blade 901 Discharge port array 902 Common liquid chamber 903 Head temperature sensor 904 Ink path 905 Filter 906 A1 substrate 907 HB substrate 908 Discharge heater 909 Top plate 906e Pawl 906f Head opening 701 Ink cartridge 702 Multi-head 703 Paper feed roller 705 Paper feed roller 706 Carriage 707 Multi nozzle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location B41J 3/04 104 K (72) Inventor Hitoshi Sugimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Kiya Non-Incorporated (72) Inventor Hiromitsu Hirabayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaya Uetsuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Miyuki Matsubara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Fumihiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (26)

[Claims] 1. In an ink jet recording apparatus for recording by ejecting ink from a recording means to a recording material, head temperature monitoring means for monitoring the temperature of the recording head and at least the temperature of the head from the energy input to the head. An inkjet recording apparatus comprising: a head temperature estimating means for estimating and a non-ejection determining means for determining the presence or absence of a non-ejection state of the recording head using at least the above two pieces of information. 2. The non-ejection determining means of the ink jet recording apparatus according to claim 1, wherein the difference between the head temperature monitor value and the head temperature estimated value is compared with a predetermined threshold value to determine the recording head failure. An ink jet recording apparatus, characterized in that the presence or absence of a discharge state is determined. 3. The ink jet recording apparatus according to claim 1, further comprising means for determining non-ejection of the recording head based on temperature change due to ejection of the recording head, temperature decrease after ejection, or both temperature changes. apparatus. 4. The ink jet recording apparatus according to claim 1, wherein the recording head is caused to perform idle ejection not used for printing, the first temperature before performing idle ejection of the recording head, and the second temperature at the end of idle ejection. The temperature and the third temperature after the lapse of a predetermined time after the completion of the idle discharge are detected, and the temperature rise value of the print head by the idle discharge indicated by the first temperature and the second temperature and the second temperature are detected. An inkjet recording apparatus, further comprising: means for performing a non-ejection determination method for determining whether or not a print head is in a non-ejection state based on a value of a temperature decrease after completion of idle ejection indicated by a third temperature. 5. The ink jet recording apparatus according to claim 1, wherein the threshold value for non-ejection determination is changed according to the state of the ink jet recording apparatus. 6. The inkjet recording apparatus according to claim 1, wherein a threshold value for non-ejection determination is changed according to at least a print mode of the inkjet recording apparatus. 7. The ink jet recording apparatus according to claim 1, wherein a threshold value for non-ejection determination is changed according to a print duty detected from print data. 8. The non-ejection determining means of the ink jet recording apparatus according to claim 1, including a period for satisfying a predetermined condition, a head monitor temperature, an estimated value of the head temperature, or at least the above two values for calculation. An ink jet recording apparatus characterized in that the presence or absence of a non-ejection state of the recording head is judged by accumulating the results and comparing the results with a predetermined threshold value. 9. The non-ejection determining means of the ink jet recording apparatus according to claim 8, wherein a calculation result including a predetermined time, a head monitor temperature, an estimated value of the head temperature, or at least the above two values is calculated. An inkjet recording apparatus, wherein the presence or absence of a non-ejection state of a recording head is determined by integrating and comparing the result with a predetermined threshold value. 10. The non-ejection determining means of the ink jet recording apparatus according to claim 8, wherein a result obtained by including a monitor temperature of the head, an estimated value of the head temperature, or at least the above two values during a scan is calculated. Add up. Further, the print duty is known from the print data prior to printing, and the integrated value is corrected. An ink jet recording apparatus characterized by determining the presence or absence of a non-ejection state of a recording head by comparing the result with a predetermined threshold value. 11. The non-ejection determining means of the ink jet recording apparatus according to claim 8, wherein the print duty is known from the print data, the print duty is integrated, and the head monitor temperature or the head is measured until the print duty reaches a predetermined amount. It is possible to determine the presence / absence of a non-ejection state of the print head by integrating the estimated value of temperature or the result of calculation including at least the above two values and comparing the result with a predetermined threshold value. An inkjet recording device characterized by the above. 12. The non-ejection determining means of the ink jet recording apparatus according to claim 2, wherein the difference between the head temperature monitor value and the head temperature estimated value is accumulated for a period that satisfies a predetermined condition, and the result is predetermined. An ink jet recording apparatus characterized by determining the presence or absence of a non-ejection state of a recording head by comparing with a threshold value. 13. The non-ejection determining means of the ink jet recording apparatus according to claim 12, wherein the difference between the head temperature monitor value and the head temperature estimated value is integrated for a predetermined time, and the result is predetermined threshold value. An ink jet recording apparatus, characterized in that the presence or absence of a non-ejection state of the recording head is determined by comparing with. 14. The non-ejection determining means of the ink jet recording apparatus according to claim 12, wherein the difference between the monitor value of the head temperature and the estimated value of the head temperature is integrated during scanning. Further, the print duty is known from the print data prior to printing, and the integrated value is corrected. An ink jet recording apparatus characterized by determining the presence or absence of a non-ejection state of a recording head by comparing the result with a predetermined threshold value. 15. The non-ejection determining means of the ink jet recording apparatus according to claim 12, wherein the print duty is known from the print data, the print duty is integrated, and the head temperature monitor value and the head temperature are measured until the print duty reaches a predetermined amount. The inkjet recording apparatus is characterized in that the presence / absence of a non-ejection state of the recording head is determined by integrating the difference between the estimated values and comparing the result with a predetermined threshold value. 16. The non-ejection determining means of the ink jet recording apparatus according to claim 1, wherein a value obtained by subtracting an estimated value of the head temperature from a monitor temperature of the head immediately after the end of the scan for printing is used immediately before the start of the next scan for printing. By comparing the value obtained by subtracting the estimated value of the head temperature from the monitor temperature of the head with a predetermined threshold value,
An inkjet recording apparatus, characterized in that the presence or absence of a non-ejection state of a recording head is determined. 17. The ink jet recording apparatus according to claim 1, further comprising means for determining whether or not the non-ejection state is recovered after performing a recovery process on the recording head which is determined to be the non-ejection state. An inkjet recording device characterized by the above. 18. The ink jet recording apparatus according to claim 4, wherein after the recovery processing is performed on the recording head determined to be in the non-ejection state, the recording head is caused to perform a blank ejection not used for printing. First before performing blank discharge
, The second temperature at the end of the idle discharge, and the third temperature after the end of the idle discharge for a predetermined time, and the recording by the idle discharge indicated by the first temperature and the second temperature is performed. An ink jet recording apparatus having means for determining whether or not the recording head has recovered from the non-ejection state based on the temperature rise value of the head and the temperature decrease value after the end of idle ejection indicated by the second temperature and the third temperature. . 19. In an ink jet recording apparatus for recording by ejecting a plurality of colors of ink from a recording means to a recording material, the recording head determined to be in a non-ejection state does not drive, and the other recording heads. An inkjet recording apparatus, which is capable of performing printing with. 20. In an ink jet recording apparatus for performing recording by ejecting a plurality of colors of ink from a recording means to a recording material, the recording head determined to be in a non-ejection state does not perform temperature adjustment, and other recording is performed. An ink jet recording apparatus characterized in that the temperature can be adjusted with a head. 21. In an ink jet recording apparatus for recording by ejecting a plurality of colors of ink from a recording means to a recording material, among print data, print data relating to a recording head determined to be in a non-ejection state is ignored. The inkjet recording device is capable of performing printing. 22. In an ink jet recording apparatus for recording by ejecting a plurality of colors of ink from a recording means to a recording material according to claim 1, the recording head judged to be in a non-ejection state does not drive, An inkjet recording apparatus capable of performing printing with a recording head other than the above. 23. In an ink jet recording apparatus for recording by ejecting a plurality of colors of ink from a recording means to a recording material according to claim 1, the recording head judged to be in a non-ejection state does not adjust temperature. An ink jet recording apparatus characterized in that temperature can be adjusted by a recording head other than the above. 24. An ink jet recording apparatus for performing recording by ejecting a plurality of color inks from a recording means to a recording material according to claim 1, the recording head being determined to be in a non-ejection state in print data. Ignore the print data,
An ink jet recording apparatus, which is capable of printing. 25. The ink jet recording apparatus according to claim 1, wherein ejection failure is determined during printing. 26. In an ink jet recording apparatus for recording by ejecting ink from a recording means to a recording material, the direct non-ejection is made prior to the direct non-ejection determination for making a final decision of non-ejection of a recording head. An inkjet recording apparatus that determines whether or not a recording head has failed to eject, using a method different from that used for determination.