JP2004255657A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device which efficiently suppresses a temperature rise of a recording head by eliminating uneven generation of heat at the recording head without adding a structure change such as a special cooling structure to the recording head, and regardless of the presence/absence of a cooling structure. <P>SOLUTION: The inkjet recording device is constructed using the recording head which has a plurality of ink discharge parts arranged corresponding to a plurality of colors of ink. The ink discharge parts have a plurality of discharge openings for discharging ink by generating a heat energy. An arrangement order in an arrangement direction of the plurality of ink discharge parts is made so that a total value of average ink discharge amounts per unit time of the ink discharge parts at a plurality (at least two or more) of the arbitrary ink discharge parts adjacent to each other in the arrangement direction does not exceed a certain set value. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet recording apparatus that performs recording by discharging ink from a recording head onto a recording medium such as paper.
[0002]
[Prior art]
2. Description of the Related Art Recording devices such as printers and copiers are configured to record an image formed of a dot pattern on a recording medium such as paper based on image information.
[0003]
The recording apparatus can be classified into an ink jet system, a laser beam system, a thermal system, a wire dot system, and the like according to the recording system. Among them, the ink jet system is configured to eject ink droplets by generating heat at a discharge port of a recording head, and to adhere the ink droplets to a recording medium to perform recording.
[0004]
In recent years, in order to enable high-speed and high-performance printing, there has been a tendency to increase the number of recording heads, such as light cyan and light magenta, and to print by mounting a plurality of recording heads of the same color on a carriage. Further, in order to improve the printing throughput, there is a tendency that the so-called print head is made longer by increasing the row of discharge ports of the print head.
[0005]
[Problems to be solved by the invention]
In the ink jet recording apparatus using the bubble jet method, since the recording head generates heat by the heater, if the recording head is excessively heated, ink cannot be discharged, a problem of non-discharging, a problem of promoting burning and deterioration of the heater, Various adverse effects are caused, such as a problem that the recording density changes when recording on a recording medium such as paper. Therefore, measures to suppress the temperature rise of the recording head are indispensable.
[0006]
As a measure for suppressing the temperature rise of the recording head, a method of basically cooling the recording head or a member connected to the recording head has been proposed.
[0007]
First, as the most common method of suppressing the temperature rise, when the print head rises to a certain set temperature, the scan continues printing, and a pause is provided between each scan, during which the natural time is set. In this method, heat is dissipated and it takes time to reduce the printing throughput.
[0008]
Next, as a method of forcibly cooling, air cooling, water cooling, or the like can be considered.
[0009]
Specifically, a method of cooling the heated recording head using a fan is known. However, fixing the fan to the carriage makes the carriage heavy, and increasing the performance of a motor for driving the carriage requires cost. It becomes difficult to increase the drive frequency of the recording head when the movement speed of the carriage is reduced by responding, and the landing position by blowing air during printing as the ink droplets become smaller. Deviation may be a concern.
[0010]
There is also a method of cooling using a liquid (a method using water or a special cooling liquid, etc.), but a flow path for flowing the cooling liquid is necessary, and the means for replacing and disposing of the cooling liquid is also taken into consideration. However, there are problems such as an increase in equipment cost, an increase in labor for replacement, an increase in recovery cost and labor.
[0011]
Further, there is a method using a heat pipe in which a heat conductive material and a heat conductive path are integrated. Specifically, the heat pipe is a copper pipe in which a heat conductive material is injected and sealed therein, and the heat generated by the recording head is removed by latent heat of vaporization when the heat conductive material changes from a liquid to a gas. In this structure, gas moves in the pipe, is cooled at another location, returns to liquid, and is supplied again to the recording head. In this case, as long as the sealed heat conductive material does not leak, maintenance (replacement or disposal) is unnecessary, but there are problems of cost increase, space shortage, and weight increase.
[0012]
It is also possible to attach a cooling fin or the like to the recording head or the heat conduction path in order to increase the cooling efficiency. However, problems such as a shortage of space, an increase in weight, and an increase in cost increase.
[0013]
As described above, in the case where the cooling mechanism is to be mounted on the print head, the structure and size of the print head having a plurality of ink ejection units are large, and the above-described problems (shortage of space, increase in weight, increase in cost, etc.) are more serious. Become noticeable.
[0014]
Further, in recent years, there has been a strong tendency to increase the speed due to multi-color and longer print heads and reciprocal printing of a carriage, and the amount of heat generated per unit time tends to increase. It has become important.
[0015]
Therefore, the present invention provides an efficient recording head without changing the structure of the recording head, such as a special cooling structure, and irrespective of the presence or absence of a cooling structure, by eliminating the bias of heat generation in the recording head. It is an object of the present invention to provide an ink jet recording apparatus capable of suppressing a rise in temperature of a recording medium.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an ink jet recording apparatus using a recording head in which a plurality of ink ejection sections having a plurality of ejection ports for generating thermal energy and ejecting ink are arranged corresponding to a plurality of color inks. In the above, the arrangement order of the plurality of ink ejection units in the arrangement direction is determined by calculating an average ink ejection amount per unit time of each of the plurality of (at least two or more) ink ejection units adjacent in the arrangement direction. It is characterized in that the total value is in an arrangement order not exceeding a certain set value.
[0017]
Further, the present invention provides an ink jet recording apparatus using a recording head in which a plurality of ink ejection sections having a plurality of ejection ports for ejecting ink by generating thermal energy are arranged in correspondence with a plurality of color inks. The arrangement order of the ink ejection units in the arrangement direction may be a value obtained by summing the average ink consumption per unit time of each of the plurality of (at least two or more) ink ejection units adjacent in the arrangement direction. Are arranged in order not to exceed the set value.
[0018]
Furthermore, the invention according to claim 3 is an ink jet recording apparatus using a recording head in which a plurality of ink ejection sections having a plurality of ejection ports for ejecting ink by generating thermal energy are arranged corresponding to a plurality of color inks. The arrangement order of the plurality of ink ejection units in the arrangement direction is determined by summing the average amount of ink generated per unit time of each of the plurality of ink ejection units (at least two or more) adjacent to the arrangement direction. It is characterized in that the arranged values do not exceed a certain set value.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0020]
In the present embodiment, a print head having ink discharge units of six colors of black, light cyan, cyan, light magenta, magenta, and yellow is used, and the print head is moved along the main scanning direction. An example in which the present invention is applied to an inkjet recording apparatus that performs line recording will be described.
[0021]
First, the main configuration of the ink jet recording apparatus will be described with reference to FIGS.
[0022]
FIG. 2 is a perspective view schematically showing the ink jet recording apparatus. In the ink jet recording apparatus shown here, the drive of a paper feed motor (LF motor) 13 composed of a stepping motor is transmitted to a pair of upper and lower paper feed rollers 10 via gears and the like, and is supplied between the paper feed rollers 10. The recording paper 11 is sent out in the sub-scanning direction (the direction shown by arrow B in the figure). The paper fed by the paper feed roller 10 is supported at its lower part by a platen plate 14 and is introduced between a pair of upper and lower paper holding rollers 15 while maintaining flatness. The paper is sent forward while being held in a plane by the paper holding roller 10 and the paper holding roller 15.
[0023]
Further, in response to the sheet transport operation, the carriage 17 reciprocates with the recording heads 100 and 200 to perform the recording operation on the sheet. That is, the head carriage 17 is driven by a carriage motor (CR motor) 16 controlled by a control system circuit to be described later, along the guide shaft 12 provided in parallel with the platen plate 14 in the main scanning direction (in FIG. (Direction shown by arrow A).
[0024]
In the recording head 100, ink ejection units 111 to 116 are arranged at regular intervals with respect to the moving direction of the head carriage 17 (the direction indicated by the arrow A), and yellow, magenta, light magenta, cyan, and light cyan. The ink tanks 101 to 106 filled with black, black (hereinafter sometimes abbreviated as Y, M, LM, C, LC, and Bk) ink cartridges 101 to 106 are detachably held. The ejection units 211 to 216 are arranged at regular intervals with respect to the moving direction (main scanning direction) A of the head carriage 17 and are filled with black, light cyan, cyan, light magenta, magenta, and yellow ink. To 206 are detachably held.
[0025]
Here, the configuration of the recording heads 100 and 200 will be described with reference to FIGS.
[0026]
FIG. 4 is a view for explaining a cross section of the recording heads 100 and 200 of the ink jet recording apparatus.
[0027]
The recording heads 100 and 200 are roughly composed of ink discharge units 111 to 116 and 211 to 216 forming discharge ports roughly, and ink tanks 101 to 106 and 201 to 206. The ink ejection unit is composed of 111 to 116 and 211 to 216 for six colors, and is connected to the corresponding ink tanks 101 to 106 and 201 to 206 for six colors by ink channels 121 to 126 and 221 to 226. . The ink stored in the ink tank is supplied to an ink ejection unit via an ink flow path, is ejected from an ejection port formed in the ink ejection unit, and is recorded on a recording medium. The triangle mark shown in the drawing is the home position side of the carriage.
[0028]
FIG. 5 is a view of the recording heads 100 and 200 as viewed from the ink ejection port side.
[0029]
In this example, two nozzle rows (even and odd rows) are provided for each color in which 128 nozzles are arranged at a pitch of 600 dpi per row. Drops are ejected onto the recording medium. Each of the ink discharge units 111 to 116 and 211 to 216 has the 256 discharge ports.
[0030]
FIG. 3 is a block diagram illustrating a configuration of a control system circuit according to the present embodiment.
[0031]
In the present embodiment, reference numeral 300 denotes a main control unit. The main control unit 300 executes processing operations such as calculation, control, determination, setting, and control, which will be described later, and control programs to be executed by the CPU 301. , A RAM 303 used as a print data buffer, a work area for processing by the CPU 301, and the like, an input / output port 304, and the like.
[0032]
The input / output port 304 is connected to the drive circuits 305, 306, 307 such as the above-described paper transport motor (LF motor) 13, carriage motor (CR motor) 16, and recording heads 100, 200. Sensors such as a head temperature sensor (head temperature detecting means) 308 for detecting the temperatures of the recording heads 100 and 200 and a home position sensor 309 for detecting the home positions of the recording heads 100 and 200 are connected. Further, the main controller 300 is connected to a host computer (not shown) via an interface circuit 310.
[0033]
Next, a recording operation of the ink jet recording apparatus having the above configuration will be described.
[0034]
First, in a state where the recording paper 11 conveyed to a predetermined position by the LF motor 13 is stopped, the CR motor 16 is rotated via the drive circuit 306 to move the head carriage 17 in one direction A1 (hereinafter, referred to as a main scanning direction). (Referred to simply as the outward direction) while energizing the electrothermal transducers at the required locations based on the print data, so that the black ink is discharged from the ink discharge units 116 and 211 to the ink discharge units 115 and 212. , Light cyan ink from the ink ejection units 114 and 213, light magenta ink from the ink ejection units 113 and 214, magenta ink from the ink ejection units 112 and 215, and yellow ink from the ink ejection units 111 and 216. Each ink is ejected and each ink is overlapped to perform one scan of color printing.
[0035]
Next, when color printing for one scan is completed, the LF motor 13 conveys the recording paper 11 by a predetermined amount and stops it, and reverses the CR motor 16 via the drive circuit 306 in order to print the next image. While moving the head carriage 17 in another direction A2 of the main scanning direction (hereinafter, simply referred to as a backward direction) while energizing the necessary portion of the electrothermal transducer on the basis of the recording data. And black ink from the ink discharge units 116 and 211, light cyan ink from the ink discharge units 115 and 212, cyan ink from the ink discharge units 114 and 213, light magenta ink from the ink discharge units 113 and 214, and the ink discharge unit. Magenta ink is ejected from 112 and 215, and yellow ink is ejected from the ink ejection units 111 and 216, respectively. To form an over image. Such a reciprocating printing operation is continued to record an image of a desired size.
[0036]
Here, the handling of the recording data will be described.
[0037]
The print data provided to the inside of the drive circuit 307 for driving the ink discharge units 111 to 116 and 211 to 216 for discharging the respective inks (Bk, LC, C, LM, M, and Y) and the print circuit 307 is set for each ink color. Correspondingly, it is divided into 6 × 2 = 12 blocks and a signal sequence, and the recording data is separately stored in the RAM 303. The CPU 301 executes the program of the ROM 302, the number of recording heads, the number of ink ejection units, and the arrangement information of the ink colors in the RAM 303 so that the inside of the driving circuit 307 corresponding to the ink colors corresponds to the recording data divided into the ink colors in the RAM 303. Control based on The print data is transmitted from the host computer in the form of image data in the form of each ink color, or the image data sent from the host computer is converted into the ink colors and print heads 100 and 200 in the main control unit 300. In some cases.
[0038]
In the present embodiment, the operation has been described in the case of reciprocating printing in the case where two print heads 100 and 200 are used and the same ink color is used in two ink ejection units (two heads twin). Instead, an ink jet recording apparatus having a single recording head may be used, and one-way printing on the outward or return path may be used instead of reciprocal printing.
[0039]
In the present embodiment, the number of ink ejection portions in the recording head is six, and inks of six colors are used. However, the number of ink ejection portions is not limited thereto, and the number of ink ejection portions may be four or eight. The same configuration is possible when the number of ink colors is equal to the number of ink ejection units or when the number of ink colors is smaller than the number of ink ejection units. Also, the arrangement of the ink colors does not need to be limited to the present embodiment.
[0040]
Next, the arrangement of the ink colors of the ink ejection unit, which is the main feature of the present invention, will be described.
[0041]
First, the difference in the amount of heat generated by each ink ejection unit will be described with reference to FIG.
[0042]
FIG. 8 shows an image data of 11 kinds of different image samples arbitrarily extracted into recording data of 6 colors (C, M, Y, Bk, LC, LM), and a printing duty of each color (over the entire unit printing area). (Percentage of the ink ejected per unit time) was calculated, and the average value of 11 types of image samples was calculated. From this, it can be seen that the printing duty of the recording data is high in the order of LM, Y, Bk, M, and C on average, depending on the image sample. That is, the higher the print duty of the print data means that the number of nozzles driven and driven by the print data in the ink discharge unit is large, and the ink discharge amount per unit time, the ink consumption amount, and the heat generation amount are large. It can be seen that the ink ejection units corresponding to LM, LC, Y, Bk, M, and C in this order have high ink ejection amounts per unit time, ink consumption amounts per unit time, and heat generation amounts per unit time.
[0043]
A description will be given of how the temperature rise of the print head changes depending on how the ink colors having different heat values per unit time correspond to the ink ejection units.
[0044]
FIG. 9 shows an ink jet recording apparatus using inks of six colors (C, M, Y, Bk, LC, and LM). It is actually measured whether they are different.
[0045]
Under the first condition in the figure, in the example where printing is performed in the order of Bk, LC, LM, C, M, and Y, since the upper two colors (LM, LC) with high duty are close to each other, the amount of temperature rise is small. Many.
[0046]
Therefore, under the second condition, as shown in FIG. 6, the amount of temperature rise is suppressed by setting the ink arrangement order to Bk, LC, C, LM, MY. That is, the effect of suppressing the temperature rise can be obtained by separating the ink ejection portions (LM, LC) having a high printing duty.
[0047]
Explaining the ink arrangement order in FIG. 6, under the second condition where the ink arrangement order is Bk, LC, C, LM, MY, the printing duty per unit time of each ink ejection unit is 20.1, In 53.3, 9.7, 52.7, 12.5, and 25.1, the sum of the printing duty per unit time of the adjacent ink ejection unit is 73.4, 63.0, 62.4, 65. 2, 37.6, all of which are below the set value 100.
[0048]
On the other hand, under the first condition in which the ink arrangement order is Bk / LC / LM / C / M / Y, the printing duty per unit time of each ink ejection unit is 20.1, 53.3, 52.7, 9. 7, 12.5, and 25.1, the sum of the print duties per unit time of the adjacent ink ejection units is 74.0, 106.0, 62.4, 22.2, and 37.6, and the set value is 100. Exists. In addition, the second condition has less variation (the difference between the maximum value and the minimum value) of the sum of the print duties per unit time of the adjacent ink ejection units than the case of the first condition, and is averaged as a whole. You can see that.
[0049]
In this manner, the arrangement of the ink ejection units is determined under the condition that the average value of two adjacent print duties does not exceed a certain set value. Various arrangements of such inks are conceivable, and a representative one (LC, C, Y, Bk, M, LM) will be described as an example with reference to FIG.
[0050]
The printing duty in this case in FIG. 7 is (high / low / high / low / low / high), and the degree of freedom is higher than that in FIG. 6 (second condition) in which high and low are always arranged alternately. Increased.
[0051]
In FIG. 7, the sum of the printing duty per unit time of the adjacent ink ejection units is 63.0, 34.8, 45.2, 32.6, 65.2, and all are below the set value 100. . Also, compared to the case of FIG. 6, the variation in the sum of the printing duty is small, and the maximum value is also small from 73.4 to 65.2. It can be said that the colors are arranged.
[0052]
FIG. 10 shows an embodiment in which the arrangement of the ink ejection portions is further increased as compared with FIG. 7 and the effect of suppressing the temperature rise is obtained. The members represented by the respective numbers are basically the same as those in FIG.
[0053]
In this example, the arrangement of the ink ejection units is determined under the condition that the average value of three adjacent print duties does not exceed a certain set value. There are many possible arrangements of such inks, and a representative one of them (LC, C, Bk, Y, M, LM) will be described as an example.
[0054]
In this case, the arrangement order of the ink ejection units can be selected from the sum of the three adjacent average values in a wider range than the two adjacent average values in FIG. 7, so that an arrangement with more flexibility can be obtained. Can be.
[0055]
Therefore, as an item for determining the arrangement order of the ink ejection units, there is a thought that it is better to separate the warm colors (YM, LM) and the cool colors (LC, C, Bk) as much as possible.
[0056]
This may occur in consideration of avoiding color mixing of ink, the order of ink ejection, and the like. In this example, the ink ejection units are arranged in consideration of two points, that is, an average print duty and a warm color / cool color system.
[0057]
The sum of the average values of the three adjacent print duties in FIG. 10 is 83.1, 54.9, 57.7, and 90.3, all of which do not exceed the set value 100. Similarly, when the sum of the average values of the three adjacent print duties in the case of FIG. 6 is calculated, the sum is 83.1, 115.7, 74.9, 90.3, and some of them exceed the set value 100. Similarly, under the first condition of FIG. 9, the number of the cases that exceed the set value 100 increases to 126.1, 115.7, 74.9, and 47.3, and if this arrangement is performed, a problem may occur in the temperature rise. is there.
[0058]
Here, both the sum of the three average values and the sum of the two average values are determined using the same set value 100. However, in the case of three, the set value may be slightly increased. Since the concept of the sum of the three average values is affected by heat generation from both adjacent neighbors, the amount of heat generated is expected to be larger than the sum of the two average values.
[0059]
In the above description, the sum (simple sum) of the average values of the print duties at two or three adjacent ink ejection units is used. However, a method of multiplying by a coefficient to obtain the sum can also be adopted. This is derived from a model that considers the degree of influence of heat from an adjacent part.
[0060]
In the above description, two or three adjacent ink ejection units have been described. However, the number of ink ejection units is not limited thereto, and the number of ink ejection units in a range affected by heat is increased to four or five. The above method can be applied when the number of ink ejection portions of the recording head increases.
[0061]
In the case of multi-pass printing such as two-pass or four-pass printing, the average printing duty per scan is 、 or の of the value in FIG. 8 (this is data in one-pass printing). In 2-pass and 4-pass printing, the average print duty per unit time is eventually the same as in FIG. 8 by increasing the drive frequency of the print head by doubling or quadrupling the speed of the carriage. Can be treated similarly. Although the drive frequency is increased, when viewed per nozzle, in the case of two passes, discharge is performed once every two times, and in the case of four passes, discharge is performed once every four times. The ejection frequency of the print head is not exceeded.
[0062]
When the ink jet recording apparatus has a plurality of print modes (one pass, two passes, four passes, etc.), FIG. 8 is obtained in each print mode, and the upper set value is set when the average print duty per unit time is the highest. Can be set or determined.
[0063]
In the above description, the arrangement of the ink colors of one recording head has been described with six ink discharge units using six color inks. However, a case where the number of ink discharge units is increased in addition to the above description will be described.
[0064]
Here, a case where six inks are used and there are 12 ink ejection units will be described with reference to FIGS. 1 and 12. Accordingly, since two ink discharge units discharge ink per color, this is called a twin.
[0065]
First, a case in which twelve ink ejection units of six color inks are configured by two recording heads (referred to as an independent twin) will be described with reference to FIG.
[0066]
FIG. 1 illustrates an embodiment in the case of an independent twin using a plurality of (two in this case) recording heads in which a plurality of ink ejection units are arranged in the main scanning direction of the carriage. The members represented by the respective numbers are basically the same as those in FIG.
[0067]
In the case of FIG. 1, the arrangement order in consideration of the average printing duty and the two points of the warm color system and the cool color system used in FIG. 10 is directly used as a mirror arrangement (LM, M, Y, Bk, C, LC) (LC, C, Bk, Y, M, and LM).
[0068]
In FIG. 1, since the recording heads are independent, the arrangement of the ink ejection units is adjusted in each recording head. The arrangement order in each recording head is the same as that described with reference to FIG. In the case of FIG. 1, due to the arrangement of the mirrors, the duty is high (LC · LC) at the boundary, and the two are adjacent to each other. However, since the recording heads are independent, the effect of heat generation is cut off by the two recording heads, and the recording head can be used without any problem.
[0069]
In FIG. 1, the sum of the average print duties of the three adjacent ink discharge units in FIG. 10 is used. However, the present invention is not limited to this, and the sum of the average print duties of the two ink discharge units as shown in FIG. Even when used, they are 65.2, 37.6, 45.2, 29.8, and 63.0, and do not exceed the set value 100.
[0070]
Further, as another ink color arrangement in the independent twin, the arrangement of the ink ejection portions (Bk / LC / C / LM / MY) in FIG. 6 is mirrored (Y / M / LM / C / LC / Bk). ) (Bk, LC, C, LM, MY), which corresponds to FIG.
[0071]
Next, a case in which twelve ink ejection units are configured by one recording head (referred to as an integrated twin) will be described with reference to FIGS.
[0072]
FIG. 11 shows an embodiment of an integrated twin in which the ink discharge units are mounted on one recording head in the order of the ink discharge units mounted on the independent twin shown in FIG. The members indicated by the respective numbers are basically the same as those in FIG.
[0073]
Also in this case, the arrangement order in consideration of the average ink duty used in FIG. 10 and the two points of the warm color system and the cool color system is directly used as a mirror arrangement (LM, M, Y, Bk, C, LC, LC, C, Bk).・ Y ・ M ・ LM) is used.
[0074]
In the case of FIG. 11 this time, since the recording head is integrated, if the arrangement is determined under the condition that the average value of two adjacent print duties does not exceed a certain set value, the mirror arrangement is performed. Since the sum of the average print duties at the boundary (LC · LC) at the boundary becomes 106.6, which exceeds the set value 100, this pattern may not be suitable for implementation.
[0075]
Therefore, as shown in FIG. 12, the mirror arrangement is arranged as (LM, M, Y, Bk, LC, C, C, LC, Bk, Y, M, LM) so that the boundary line does not exceed the set value. . In this case, since the sum of the average print duty of (C · C) is lower than the set value 100, it is possible to carry out the embodiment. Further, the sum of the other two average print duties does not exceed the set value 100.
[0076]
In the twin described above, the average print duty of each ink color in FIG. 8 is discharged by two ink discharge units for one ink color, but image data corresponding to each ink color is transmitted to the ink discharge units. The average print duty is normally halved when the drive data is used, but the printing speed of the carriage 17 is doubled as in the case of two-pass printing. The average printing duty per unit time is not changed by doubling the driving frequency of the. Therefore, the set value and the average print duty are used for calculation and determination as in the case of the single head.
[0077]
Further, the twin in the above description is based on the premise of reciprocal printing, and the 12 ink ejection sections are ejected in the forward path and the return path in accordance with the drive data for 12 pieces. As shown in the figure, the 11 ink ejection units are arranged in the order of LM, M, Y, Bk, LC, C, LC, Bk, Y, M, and LM, and the C, LC, Bk, In the case of Y, M, and LM, printing may be performed on the left side by LM, M, Y, Bk, LC, and C.
[0078]
Note that the first purpose of the twin is to suppress the color unevenness in the reciprocating printing by making the ejection order of the ink colors in the reciprocating printing the same. The distribution control of the recording data is performed so that the values become equal.
[0079]
In the case of FIG. 13, the sum of the average print duties of three adjacent ink ejection units is used, but the sum of (LC, C, LC) is not taken into account. That is, since LC, C, and LC do not occur simultaneously on the outward path or the return path, the influence of the LC heat generation on the left side is low on the outward path, and the influence of the LC heat generation on the right side LC is low on the return path and can be ignored. Here, the drive frequency cannot be doubled, and the image data is not divided into two when making the drive data, so that the print duty and the set value are treated in the same manner.
[0080]
Similarly to FIG. 13, in FIGS. 11 and 12, it is also possible to perform printing with C, LC, Bk, Y, M, and LM on the right side on the outward path and with LM, M, Y, Bk, LC, and C on the left side on the return path. At this time, as in FIG. 13, the sum of the three (LC, C, LC) is not taken into account, so the applicable range is also shown in FIG. 11, but the driving frequency can be doubled. However, the speed of printing, which is the second object of the twin, is somewhat limited.
[0081]
In the above description of the embodiment, the case where the ink tanks 101 to 106 and 201 to 206 are directly mounted on the recording heads 100 and 200 and move together with the carriage 17 has been described. The ink tanks 101 to 106 and 201 to 206 are separated from the carriage 17 by lengthening the connection to the ink tanks 121 to 126 and 221-226 with ink tubes or the like. The same concept can be used even when the ink capacity is further increased by combining them into one ink tank. The ink path is arranged to go to the two ink ejection units.
[0082]
In the above description of the embodiment, the setting value for determining the sum of the average print duty is 100 (%). However, the present invention is not limited to this. Other values may be used, and the method of obtaining the set value is not limited, but some methods will be described below.
[0083]
First, as a first method, there is a statistical method based on the average print duty of each of the six ink colors. One of the methods is to calculate the total (173.4) of the average print duty of each of the six ink colors. A method is conceivable in which the average value (28.9) of the six colors is calculated by dividing by 6, and a value (81.6) obtained by adding this to the maximum average print duty (52.7) of the six colors is set as a set value. Can be Here, the numerical values in parentheses are values obtained by the present method from the average print duty in FIG.
[0084]
The current setting value 81.6 also satisfies that the maximum value 73.4 of the sum of the average print duties of two adjacent colors in the ink color arrangement of FIG. 6 is lower than the setting value. Similarly, when the determination is made based on the sum of the average print duties of the three colors, the total (173.4) of the average print duties of the six ink colors is obtained, and the average value (28.9) of the six colors is obtained. The average value (28.9) is doubled, and the value (110.5) obtained by adding the maximum average print duty (52.7) of the six colors is set as the set value. The maximum value 90.3 of the average print duty of three adjacent colors in the ink color arrangement of FIG. 10 satisfies that it is lower than the current set value 110.5.
[0085]
Next, there is an experimental method as a second method. As one of the methods, printing is performed for a certain continuous time by shaking the printing duty of the ink discharging unit of two adjacent colors, and the temperature rise and the change of the discharging amount are measured. A method of observing and finding a range in which a change in the ejection amount is allowable and a temperature rise is also allowable, finds a maximum allowable printing duty at that time, and sets a value obtained by adding the maximum printing duty of two adjacent colors to a set value. Can be considered. When the determination is made based on the sum of the average print duties of the three colors, the set values are determined by shaking the print duties of the adjacent three color ink ejection units and finding the maximum value in the same manner.
[0086]
In the description of the present embodiment, the image samples for which the average print duty is obtained are for 11 different image samples that are arbitrarily extracted, but are not limited thereto. For example, the number of image samples can be increased or reduced to some extent. Further, the present invention can be implemented by changing the type of the image sample according to the field of the target inkjet recording apparatus (for example, for graphics, CAD, and documents such as characters). Depending on the case, the order of increasing the average print duty may change, but the present invention can be realized in the same manner.
[0087]
It should be noted that the eleven different image samples in the present embodiment are of a wide variety of types.
[0088]
【The invention's effect】
As is apparent from the above description, according to the present invention, the bias of the generation of heat at the time of recording of the recording head having the plurality of ink ejection units is reduced by the arrangement of the ink colors, so that the configuration is simple and inexpensive. In addition, it is possible to suppress the temperature rise of the recording head without lowering the printing throughput. That is, by suppressing the temperature rise of the recording head, stable ejection can be performed, and a high-speed inkjet recording apparatus with good image quality can be provided at low cost.
[0089]
In addition, it is possible to provide a method that can easily take in other conditions such as symmetrical arrangement and grouping of colors as well as averaging of heat generation and suppression of the maximum value as conditions for determining the arrangement of ink colors.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a specific arrangement order of ink of an inkjet recording head in an embodiment of the present invention (particularly, a twin type using two recording heads).
FIG. 2 is a perspective view schematically showing an inkjet recording apparatus.
FIG. 3 is a block diagram illustrating a configuration of a control system circuit.
FIG. 4 is a view for explaining a cross section of a recording head (particularly, a twin type using two recording heads) of the ink jet recording apparatus.
FIG. 5 is a view of two recording heads as viewed from ink ejection ports.
FIG. 6 is a diagram illustrating an example of a specific arrangement order of ink of an ink jet recording head in an embodiment of the present invention (particularly, a single type using one recording head).
FIG. 7 is a diagram illustrating another example of a specific arrangement order of the inks of the inkjet recording head in the embodiment of the present invention (particularly, a single type using one recording head).
FIG. 8 is a diagram summarizing the results of analyzing the colors of ink and the printing duty thereof for various images.
FIG. 9 is a diagram showing the relationship between the arrangement order of the ink ejection units and the change over time in the amount of temperature rise according to the present invention.
FIG. 10 is a diagram illustrating an example of a specific arrangement order of inks of an ink jet recording head in an embodiment of the present invention (particularly, a single type using one recording head).
FIG. 11 is a diagram illustrating an example of a specific arrangement order of inks of an inkjet recording head which is not an embodiment of the present invention.
FIG. 12 is a diagram illustrating an example of a specific arrangement order of ink of an ink jet recording head in an embodiment of the present invention (particularly, a twin type using one recording head).
FIG. 13 is a diagram illustrating another example of the specific arrangement order of the inks of the inkjet recording head in the embodiment of the present invention (particularly, the twin type using one recording head).
[Explanation of symbols]
10 Paper feed roller
11 Recording paper (recording medium)
12 Guide shaft
13 LF motor
14 Platen plate
15 Paper press roller
16 CR motor
17 Carriage
100,200 recording head
101 to 106, 201 to 206 Ink tank
111 to 116, 211 to 216 Ink ejection unit
121-126, 221-226 Ink flow path
300 Main control unit
301 CPU
302 ROM
303 RAM
304 I / O port
Driving circuit
308 Head temperature sensor
309 Home position sensor
310 Interface circuit

Claims (12)

In an ink jet recording apparatus using a recording head in which a plurality of ink ejection units having a plurality of ejection ports for ejecting ink by generating thermal energy are arranged corresponding to a plurality of color inks,
The arrangement order of the plurality of ink ejection units in the arrangement direction is the sum of the average ink ejection amount per unit time of each of the plurality of (at least two or more) ink ejection units adjacent in the arrangement direction. An ink jet recording apparatus, wherein the values are arranged in an order that does not exceed a certain set value. In an ink jet recording apparatus using a recording head in which a plurality of ink ejection units having a plurality of ejection ports for ejecting ink by generating thermal energy are arranged corresponding to a plurality of color inks,
The arrangement order of the plurality of ink ejection units in the arrangement direction is the sum of the average ink consumption per unit time of each of the plurality of ink ejection units adjacent to each other in the arrangement direction (at least two or more). An ink jet recording apparatus, wherein the values are arranged in an order that does not exceed a certain set value. In an ink jet recording apparatus using a recording head in which a plurality of ink ejection units having a plurality of ejection ports for ejecting ink by generating thermal energy are arranged corresponding to a plurality of color inks,
The arrangement order of the plurality of ink ejection units in the arrangement direction is the sum of the average amount of heat generated per unit time of each of the ink ejection units in an arbitrary plurality (at least two or more) of the ink ejection units adjacent in the arrangement direction. An ink jet recording apparatus, wherein the values are arranged in an order that does not exceed a certain set value. The ink jet recording apparatus according to any one of claims 1 to 3, wherein the number of the plurality of arbitrary ink ejection units adjacent in the arrangement direction is two or three. 5. The ink jet recording apparatus according to claim 1, wherein the number of the plurality of ink ejection units is equal to or more than the number of ink colors and less than twice. The number of ink ejection units is at least six, and inks of six colors of black (Bk), cyan (C), magenta (M), yellow (Y), light cyan (LC), and light magenta (LM) are used. 6. The ink jet recording apparatus according to claim 5, wherein the ink is ejected from an ink ejection unit. 5. The ink jet recording apparatus according to claim 1, wherein the number of the plurality of ink ejection units is twice or more than the number of ink colors. The number of ink ejection units is at least 12, and each of the inks of six colors of black (Bk), cyan (C), magenta (M), yellow (Y), light cyan (LC), and light magenta (LM) is used. The ink jet recording apparatus according to claim 7, wherein the ink is ejected from two ink ejecting units. 9. The ink jet recording apparatus according to claim 7, wherein the apparatus comprises one or two or more recording heads. The plurality of ink ejection units include yellow (Y), magenta (M), light magenta (LM), cyan (C), light cyan (LC), black (Bk), black (Bk), light cyan (LC), The ink jet recording apparatus according to claim 7, wherein the inks are arranged in the order of cyan (C), light magenta (LM), magenta (M), and yellow (Y). A value obtained by summing the average ink ejection amount per unit time of each ink ejecting unit in a plurality of (at least two or more) ink ejecting units adjacent to each other across the two recording heads. 10. The ink jet recording apparatus according to claim 9, wherein is not considered. The ink jet recording apparatus according to any one of claims 5 to 7, wherein the arrangement order is determined independently for the ink ejection unit used in the forward printing and the ink ejection unit used in the backward printing.

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