JP2887012B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus,
In particular, the present invention relates to an ink jet recording apparatus that performs recording by discharging ink onto a recording material.

[0002]

2. Description of the Related Art Conventionally, as an image recording apparatus, an ink jet recording apparatus for performing recording by discharging ink onto a recording material has been known. The ink jet recording apparatus is a non-impact type recording apparatus, and has features such as low noise and easy recording of color images by using multi-color inks. I am doing it.

FIG. 13 is a schematic perspective view of an ink jet recording apparatus according to a conventional example. In FIG. 13, the recording material 5 wound in a roll shape is sandwiched between the feeding rollers 3 via the conveying rollers 1 and 2, and is connected to the sub-scanning motor connected to the feeding roller 3.
The sheet is conveyed in the direction f in FIG. Guide rails 6 and 7 are provided in parallel across the recording material 5, and the carriage 8 is guided along the guide rails 6 and 7, and a recording head unit 9 mounted on the carriage 8 is provided. Are scanned right and left.

The carriage 8 has four color recording heads 9Y, 9M, 9C, yellow, magenta, cyan, and black.
9Bk, and four color ink tanks are arranged for each of these recording heads. The recording material 5 is intermittently fed by the print width of each recording head.
When the recording material 5 is stopped, the recording head scans in the P direction, and performs recording by discharging ink droplets according to the image signal.

In a serial scan type ink jet recording apparatus as shown in FIG. 13, as shown in FIG. 14, a multi-nozzle recording head 91 having a plurality of nozzles arranged in parallel is scanned in the direction A to record an image having a width d. When the recording of one line is completed, intermittent feed is performed by the recording width of the multi-nozzle recording head 91 in the direction opposite to the direction B shown in FIG. This scanning is shown in FIG.
Recording is performed by repeating in the order of (2) and (3). The recording width d is determined by the number of nozzles and the recording density of the head. When the number of nozzles is 256 and the recording density is 400 dots / inch (dpi), 256 × 25.4 / 4
00 = 16.256 mm.

On the other hand, an image recording apparatus using a recording head has been proposed which uses a plurality of recording heads having different densities in order to improve gradation. For example,
2. Description of the Related Art In an ink jet recording apparatus, a dark ink recording head that performs printing with a high density ink and a light ink recording head that performs printing with a low density ink are used.

FIG. 3 shows the duty of driving the dark and light ink recording heads in response to an input image signal. In FIG. 3, the horizontal axis represents the input image signal, and the vertical axis represents the output corresponding to the input image signal, that is, the head print signal supplied to the recording head. Further, the size of the maximum level is set to 255, and the size of the intermediate level is set to 127.
And When the input image signal is small, that is, 0 to
Up to 127, only the light ink recording head is used, and when the input image signal level exceeds 127, both the light ink recording head and the dark ink recording head are used to reduce the printing duty of the light ink recording head, Printing duo
Gradually increase the tee. When the input image signal is at the maximum of 255, only the dark ink recording head is used. By driving in this manner, an image density as shown in FIG. 4 is finally obtained.

Although the image density characteristics shown in FIG. 4 can be obtained only with a dark ink recording head, when a dark and light ink recording head is used, the feeling of dot roughness in a low density portion is reduced, and an image having a smooth gradation is obtained. There is an advantage that can be obtained. However, when the image recording is performed with the dark and light ink recording heads as described above, the ink consumption of the light ink recording head is large, so that the ink amount used for printing as a whole increases, and the ink bleeding on the recording medium is caused. Is a problem.

When image recording is performed by serial scanning as shown in FIG. 14, this is not a problem if ink bleeding on the recording paper can be neglected. However, if the amount of ink to be printed increases, as shown in FIG. And the printing width spreads to d + Δd. In such a case, ink overlaps at the joint of scanning, the density of the overlapped portion increases, and black streaks appear on the image.

Therefore, in order to solve this problem, it is conceivable to set the sub-scanning width in the B direction to d + Δd.
According to this method, when the amount of ink to be printed is small, a new problem arises in that the seam of scanning becomes a white stripe. On the other hand, an application disclosing one method for solving this problem has been filed by the present applicant (Japanese Patent Application Laid-Open No.
No. 3326). In this method, an image signal given to an end nozzle of a recording head is converted into a table as shown in FIG. With this configuration, even if the input signal has a high value, the maximum value of the output is suppressed to F. Therefore, the maximum value of the amount of ink printed by the end nozzles is suppressed, and black lines are less likely to occur.

[0011]

However, the amount of ink ejected varies with the print history of the recording head. This is because, when the environmental temperature is high, or when the temperature of the recording head increases due to continuous printing of a high-density image, the viscosity of the ink decreases as the temperature increases, and the ink ejection amount increases. That's why. When the ink ejection amount increases in this way, black streaks appear at the joint of scanning.

When a dark and light ink recording head is used, image signals are distributed as shown in FIG. 3, so that the frequency of use (printing duty) of the light ink recording head increases, the temperature rises sharply, and the ink is discharged. There have been problems such as an increase in the discharge amount. For this reason, the above-mentioned JP-A-2-332 is simply referred to.
As described in Japanese Patent Application Laid-Open No. 6-64, simply suppressing the amount of ink ejected from the end nozzles may not provide a sufficient effect in preventing the occurrence of black streaks.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and when printing is performed using a plurality of printing heads of the same color and different ink densities, printing is performed because continuous printing is continued. It is an object of the present invention to provide an image recording apparatus capable of making black streaks or white streaks at scanning joints inconspicuous even when the temperature of the head rises.

[0014]

According to the present invention, there is provided an image recording apparatus comprising a plurality of recording heads having similar colors and different ink densities, wherein each recording head has a plurality of recording elements. In an image recording apparatus that performs image recording using a head group, a temperature detection unit that detects a temperature related to a recording head of the recording head group, and a temperature detection unit that detects the temperature of each of the recording heads according to the temperature detected by the temperature detection unit. Control means for controlling the amount of ink recorded by the recording element at the end.

Further, by providing a plurality of recording head groups, each having a different color of ink,
An image recording apparatus capable of recording is provided.

The input image signal is divided by the signal dividing means into a plurality of signals corresponding to each of the recording heads. Further, as an example of the control means, a plurality of γ
A method of controlling an amount of ink recorded by a recording element at an end of each recording head by converting an input image signal using a γ table selected from the recording tables and driving the recording head. Can be

It is preferable that the recording head is a recording head that discharges ink by using thermal energy, and is provided with an electrothermal converter for generating thermal energy to be applied to the ink. Further, it is more preferable that the recording head ejects ink from an ejection port by utilizing a pressure change caused by growth and shrinkage of bubbles caused by film boiling caused by heat energy applied by the electrothermal transducer.

The image recording apparatus according to the present invention is further provided with an image.
A copier can be obtained by combining the bleeder section and the control section.

Also, a facsimile apparatus can be obtained by combining the image recording apparatus according to the present invention with an image reader section, a control section and a facsimile transmitting / receiving section.

A word processor can be obtained by combining the image recording apparatus according to the present invention with an input unit, a control unit and a display unit.

Further, a computer can be obtained by combining the input unit, the control unit and the display unit with the image recording apparatus according to the present invention.

Further, the image recording apparatus according to the present invention includes a plurality of recording heads of the same color and different ink densities, and an image recording apparatus using a recording head group in which each recording head has a plurality of recording elements. In the printing apparatus, a temperature detecting means for detecting a temperature related to a print head of the print head group, and a drive signal given to a print element at an end of each of the print heads according to the temperature detected by the temperature detecting means And control means for controlling the size of.

Further, the image recording apparatus according to the present invention includes a plurality of recording heads having similar colors and different ink densities, and the image recording is performed by using a recording head group in which each recording head has a plurality of recording elements. In the printing apparatus, a temperature detecting means for detecting a temperature related to a print head of the print head group, and a pixel corresponding to a pixel printed by a print element at an end of each print head and a pixel printed around the pixel. Calculating means for calculating the magnitude of each image signal given to the printing element for each print head according to a predetermined function, based on the value obtained by the calculating means and the temperature detected by the temperature detecting means, Control means for controlling the amount of ink recorded by the recording element at the end of each recording head. In addition, it is preferable that the calculating means calculates the sum of the magnitudes of the image signals for each recording head.
Preferably, the calculating means calculates the sum of the respective values obtained by weighting the values of the respective image signals according to the positions of the respective pixels.

Further, the image recording apparatus according to the present invention includes a recording head group having a plurality of recording heads of the same color and different ink densities for each color, and each recording head has a plurality of recording elements. In the image recording apparatus, a temperature detection unit that detects a temperature related to the recording heads of the recording head group, and an image signal corresponding to a pixel recorded by a recording element at an end of each recording head of the recording head group. Calculating means for calculating the size in accordance with a predetermined function; and, based on the value obtained by the calculating means and the temperature detected by the temperature detecting means, the amount of ink recorded by the recording element at the end of each recording head. Control means for controlling the amount;
It is characterized by having. In addition, it is preferable that the calculating means calculates a sum of magnitudes of the respective image signals. Here, it is preferable that the calculating means weights the values of the respective image signals in accordance with the degree of bleeding of the respective color inks on the recording medium, and calculates the sum of the obtained respective values.

Further, the image recording apparatus according to the present invention comprises a plurality of recording heads of similar colors and different usage frequencies, wherein each recording head performs image recording using a recording head group having a plurality of recording elements. In the apparatus, a temperature detecting means for detecting a temperature related to a recording head of the recording head group, and an ink recorded by a recording element at an end of each of the recording heads according to the temperature detected by the temperature detecting means. And control means for controlling the amount. Here, the use frequency is a frequency when each recording head unit is used based on a recording method corresponding to the recording apparatus.

Further, the plurality of recording heads have different amounts of ink recorded by the respective recording heads due to different use frequencies. Furthermore, the image recording apparatus according to the present invention is an image recording apparatus that includes a plurality of recording heads having similar colors and different ink densities, and performs image recording using a recording head group in which each recording head has a plurality of recording elements. A temperature detecting unit provided in an ink supply path to the recording head, and controlling an amount of ink recorded by a recording element at an end of each recording head according to the temperature detected by the temperature detecting unit. And control means for performing the control.

Further, in the present invention, the amount of ink recorded by the recording element at the end of each recording head is controlled, but the expression "recording element at the end of the recording head" is used for the recording head. This includes both the case where only the outermost recording element is included and the case where the outermost recording element and a recording element in the vicinity thereof are included, and in other words, the case where at least the outermost recording element is included. be able to.

[0028]

According to the present invention, the end portions of a plurality of recording heads having the same color but different ink densities, such as a dark ink recording head and a light ink recording head, according to the recording head temperature detected by the head temperature detecting means. The amount of ink recorded by the recording element is controlled. Therefore, even when the temperature of the recording head rises sharply, generation of black stripes on the recording medium is suppressed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 2 is a schematic perspective view showing an example in which the image recording apparatus according to the present invention is applied to an ink jet recording apparatus. The difference between the ink jet recording apparatus shown in FIG. 2 and the ink jet recording apparatus shown in FIG. 13 described above with respect to the portions expressed in the drawing is that the recording heads of each color are formed by a dark ink recording head and a light ink recording head, respectively. The point is that it is composed of a combined recording head group.

In FIG. 2, the recording material 5 wound in a roll shape is sandwiched between the feeding rollers 3 via the conveying rollers 1 and 2, and is connected to the sub-scanning roller connected to the feeding roller 3. The sheet is conveyed in the direction f in FIG. Guide rails 6 and 7 are provided in parallel across the recording material 5, and the carriage 8 is guided along the guide rails 6 and 7, and a recording head unit 9 mounted on the carriage 8 is provided. Are scanned right and left.

[0032] The carriage 8 yellow - dark ink recording heads 9Y ₁ and the light ink recording heads 9Y _2, the dark ink recording head 9M ₁ and the light ink recording heads 9M ₂ of magenta, dark cyan inks recording heads 9C ₁ and light Ink recording head 9C ₂ , black dark ink recording head 9
Bk ₁ and has a light ink recording head 9Bk ₂ of 4-color and a recording head for ejecting the gray ink each is eight mounted in total, with respect to these recording heads, not shown but corresponding to each ink Eight ink tanks are arranged respectively. The recording material 5 is intermittently fed by the print width of each recording head. When the recording material 5 is stopped, the recording head scans in the P direction and ejects ink droplets according to image signals to perform recording. Is performed.

FIG. 1 is a block diagram showing a configuration example of a control system according to a first embodiment of the present invention. For simplicity of description, in the drawing, only the dark ink print head and light ink print head for cyan are shown among the dark ink print heads and light ink print heads provided for each color. I have.

Reference numeral 21 denotes an input image signal, and reference numeral 22 denotes a gradation distribution table as shown in FIG. 3, which constitutes a signal dividing means for dividing the input image signal into a plurality of signals corresponding to each recording head. It is a distribution table ROM.
When the density distribution table ROM 22 is composed of an 8-bit ROM, the upper 4 bits are used for the dark ink recording head, and the lower 4 bits are used for the light ink recording head.
Further, the density distribution table ROM 22 may be composed of two ROMs for the dark ink recording head and the light ink recording head.

The input image signal is a table RO
When input to M22, an address corresponding to the size of the input image signal is specified, and a predetermined signal stored in the address is output. The result is as shown in the shading distribution table of FIG. Here, when the input image signal is small, for example, 0 to 127, a signal using only the light ink recording head is output. When the input image signal level exceeds 127, both the light ink recording head and the dark ink recording head are used. A signal is output to reduce the printing duty of the light ink recording head and gradually increase the printing duty of the dark ink recording head. When the maximum input image signal is 255, a signal using only the dark ink recording head is output.

Reference numeral 23 denotes a dark ink recording signal after distribution, 2
4 is a light ink recording signal after distribution, 25a, 25b
Is a gamma table ROM, 26 is a dark ink recording head drive signal after edge processing, 27 is a light ink recording head drive signal after edge processing, 28 is a dark ink recording head,
Reference numeral 9 denotes a light ink recording head, and reference numeral 32 denotes a control signal indicating whether or not an input image signal corresponds to an end nozzle.

The input image signal 21 is input to a density distribution table ROM 22 and is distributed to a dark ink recording signal 23 and a light ink recording signal 24. These signals are given by γ
The data is input to the table ROMs 25a and 25b and converted into a table. Reference numerals 30a and 30b denote temperature sensors attached to the recording heads 28 and 29, which detect the temperatures of the recording heads and generate temperature signals 31a and 31b corresponding to the detected temperatures.
Is output to the γ table ROMs 25a and 25b. Here, the .gamma. Table is understood in a broad sense and is a table representing a relationship when an input image signal is converted into a print signal.

FIG. 5 shows the .gamma. Tables stored in the .gamma. Table ROMs 25a and 25b, where A is a table without any conversion, and B, C, D, E, F, and G are input. This is a γ table for suppressing an output signal when the signal is large. When the control signal 32 indicates a nozzle other than the end nozzle, the table A is selected and the input signal is output to each recording head as it is. When the control signal 32 indicates the end nozzle, one γ table is selected from B to G to suppress the maximum print ink amount, and the dark ink is selected by using the selected γ table. The recording signal 23 and the light ink recording signal 24 are converted, and the converted signals are input to the binarization circuit 33, and are converted to a binary signal by a dither method, an error diffusion method, or the like.
After being digitized, they are input to each printhead as printhead drive signals 26 and 27.

FIG. 6 shows a dark ink recording head 9 for cyan.
Is a diagram showing a state in which the C ₁ nozzle viewed from placed side, 51 and 54 are nozzles arranged at the outermost ends of both upper and lower, 52 and 53 respectively 2 the outermost ends The nozzle arranged at the th. In the first embodiment, when the control signal 32 indicates the end nozzles 51 and 54, the recording head drive signal input to the end nozzles 51 and 54 is, as described above, the signal shown in FIG. B ~
The signal after the maximum print ink amount is suppressed by the γ table selected from G.

Which one of the tables B to G is to be used is determined by the temperature signals 31a and 31b. As the temperature increases, the γ table is changed in the order of B → C → D → E → F → G. The γ table is switched. Such an operation is similarly performed for the other yellow, magenta, and black dark ink print heads and light ink print heads. The maximum level of the image signal applied to the nozzles is suppressed to a low level, so that even when the temperature changes, control can be performed so that black streaks and white streaks at scanning seams are not noticeable.

(Second Embodiment) The second embodiment differs from the first embodiment in the method of converting an input image signal. In other respects, the configuration is the same, and the description is omitted. In the first embodiment, it is determined whether only the input image signal corresponding to the end nozzle of the recording head has a high density or not. If the density is high, the maximum printing ink is determined by the γ table shown in FIG. We decided to curb the amount. However, when only the image signal has a high density by chance, the dots of the end nozzles are thinned out despite the small spread of the image width due to bleeding, which may cause an inconvenience in the image recording result. obtain. In addition, when the amount of ink printed around the printing portion by the end nozzle is large, the ink is affected by the bleeding. Therefore, a sufficient effect cannot be obtained unless the printing amount of the end nozzle is further reduced. In some cases.

The second embodiment of the present invention has been improved so that such inconvenience does not occur. FIG. 7 is an explanatory diagram of the second embodiment, and FIG. 8 is a block diagram illustrating a configuration example of a control system of the second embodiment. In FIG. 8, for the sake of simplicity, in the drawing, only the dark ink recording head for cyan is shown among the dark ink recording heads and light ink recording heads provided for each color.

In FIG. 7, reference numeral 52 denotes a matrix of image signal data. The i-th row is the image signal data given to the end nozzle in the previous scan, and the j-th row is the end nozzle in the current scan. And the k-th row is the image signal data given to the second nozzle from the end. The m-th column is a pixel of interest according to the current recording, and l
The column is a pixel related to the previous recording, and the column n is a pixel related to the next recording.

In the second embodiment, a 3 × 3 pixel matrix centering on the pixel (j, m) recorded by the end nozzle is used, and the sum of the image signal data of the pixels in this matrix is used. The degree of suppression of the amount of ink recorded by the end nozzle is changed. That is, the image signal data is weighted according to the position of the pixel in the matrix, the sum of the image signal data after multiplication by the weighting coefficient is calculated, and when the sum is large, the end nozzle Is to reduce the value of the drive signal given to.

FIG. 8 shows an example of the configuration of a control section for performing such processing. Reference numerals 60a to 60i denote buffers for temporarily storing image data, which temporarily store and output pixel data corresponding to the pixels shown in FIG. 61a~61i is multiplier, image de coefficients alpha ₁ to? ₉ respectively - outputs the result to the data. An adder 62 adds all the outputs of the multipliers 61a to 61i and outputs the result. The addition output and the temperature signal 31 from the temperature sensor 30 are input to the ROM 80.

The ROM 80 selects an optimum γ table according to the combination of the addition output and the temperature signal, and outputs the selection signal. That is, the gamma texts of B to G shown in FIG.
The larger the added output signal and the higher the temperature, the larger the signal suppression amount, that is, the selection signal of the γ table close to G is output.

Note that an optimum γ table is selected according to the combination of the sum output and the magnitude of the temperature signal.
A gamma table to be selected corresponding to the combination is determined by experiment from a plurality of gamma tables, and the gamma table selection data is stored in a predetermined address. For example, when the addition output is large and the temperature signal is large, a selection signal for selecting a G γ table having the largest signal suppression amount, for example, is output. If the addition output is large and the temperature signal is small, a selection signal for selecting, for example, the γ table of E is output. When the addition output is small and the temperature signal is large, a selection signal for selecting, for example, the γ table of C is output. If the addition output is small and the temperature signal is small, a selection signal for selecting, for example, the B γ table is output.

Therefore, when the addition output and the temperature signal are inputted, the ROM 80 outputs the selection signal of the optimum γ table from the address designated corresponding to the combination of the addition output and the temperature signal. become.

The .gamma. Table ROM 25 converts the dark ink recording signal 23 into a table using the .gamma. Table corresponding to the selection signal.
The recording head 28 is converted according to the drive signal after the conversion.
Is driven to perform image recording. Reference numeral 32 denotes a control signal indicating whether or not the input image signal corresponds to the end nozzle. When indicating a nozzle other than the end nozzle, the table A is selected, and the input signal is input. The signal is output to each recording head as it is. When the control signal 32 indicates the end nozzle, the gamma tables B to G are selected as described above, and the maximum print ink amount is suppressed.

When such an operation is performed for each of the dark ink recording heads for yellow, magenta, cyan, and black and each light ink recording head, not only the end nozzles but also the ink jet recording apparatus using both dark and light inks can be used. In consideration of the amount of ink around the ink, the amount of ink can be suppressed according to the head temperature, and a great effect can be obtained by preventing black stripes.

(Third Embodiment) The third embodiment differs from the first embodiment in the method of converting the input image signal. In other respects, the configuration is the same, and the description is omitted. In the third embodiment, the sum of the magnitudes of the image signals given to the respective end nozzles of the black, magenta, yellow, and cyan dark ink print heads and light ink print heads is obtained, and based on the value of this sum. , An optimal γ table is selected.

In the case of color recording, since the recording heads of a plurality of colors are used, the amount of ink is larger than that in the case of a single color. Since the total ink amount is the sum of the ink amounts of each color, simply applying the present invention to each color independently requires
In some cases, a sufficient effect cannot be obtained. Therefore, the third embodiment improves this point.

FIG. 9 is a block diagram showing a configuration example of the control system of the third embodiment. For the sake of simplicity, in the drawing, only the dark ink print head for cyan is shown among the dark ink print heads and light ink print heads provided for each color, but black, magenta, The same applies to each of the yellow ink print heads and the light ink print heads.

In FIG. 9, 51 to 58 (C ₁ , C ₂ ,
M ₁ , M ₂ , Y ₁ , Y ₂ , Bk ₁ , Bk ₂ ) are image signals after shading of black, magenta, yellow, and cyan, respectively, and 40 is an arithmetic processing unit. The arithmetic processing unit 40 obtains the sum after weighting each signal.
Here, the magnitudes of the respective gray-scale signals of cyan, magenta, yellow and black are represented by C ₁ , C ₂ , M ₁ , M ₂ , Y ₁ ,
Assuming that Y ₂ , Bk ₁ and Bk ₂ , S = α ₁ C ₁ + α ₂ C ₂ + α ₃
M ₁ + α ₄ M ₂ + α ₅ Y ₁ + α ₆ Y ₂ + α ₇ Bk ₁ + α ₈ Bk ₂ is obtained. α _{1 to} α ₈ are weighting coefficients, which can be experimentally obtained from the magnitude of the bleeding rate of each color ink on the recording medium. If a sufficient effect can be obtained with a simple sum, all the coefficients α _{1 to} α ₈ may be set to 1.

The S signal 41 and the temperature signal 31 output from the temperature sensor 30 are input to the ROM 42. R
As in the second embodiment, the OM 42 outputs a selection signal 43 for selecting the optimum .gamma. Table according to S and the temperature, the optimum .gamma. Table is selected in the .gamma. Is converted into a table, and a driving signal for driving the dark ink recording head 28 is output.

Reference numeral 32 denotes a control signal indicating whether or not the input image signal corresponds to the end nozzle. When indicating a nozzle other than the end nozzle, the table A is selected. Then, the input signal is output to each recording head as it is.

If this operation is performed for each of the dark and light ink recording heads of the color, even in the case of color recording, the end portion corresponding to the head temperature is taken into consideration in consideration of the total amount of ink of each color. Can be suppressed, and the occurrence of black streaks at the end can be suppressed.

[0058] Further, upon obtaining the S in the above embodiments, although a case of obtaining by calculating the sum of the magnitudes of the color signals has been described as an example, the present invention is not limited thereto, C ₁ ^2, M1 ^2, Y1 ^2, Bk ² or _{C 1 × M 1, M 1} × Y 1
For example, not only a first-order polynomial but also a second-order term or a higher-order polynomial including a third-order or higher term may be used.
The function to be used may be determined to be the most effective according to the result of the experiment. However, since the bleeding phenomenon is non-linear, the use of various non-linear functions is allowed.
These cases are also included in the scope of the present invention.

When the recording head is of a piezoelectric type using a piezo element, the ink discharge amount may be directly controlled in accordance with an input signal by changing the drive voltage.

In the above embodiment, the temperature measurement
It was performed by directly measuring the temperature of the recording head,
In the case of a piezoelectric recording head using a piezo element, the temperature of ink supplied to the recording head may be measured directly or indirectly without directly measuring the temperature of the recording head. Good. The reason is that the discharge amount of the ink increases as the temperature of the ink increases. In this case, the temperature detecting means is disposed, for example, at any part in the ink supply path, and the temperature of the ink supply tube connecting the ink tank and the recording head or the temperature of the ink itself, or the ink tank. It is better to measure the temperature.

The position where the temperature sensor is provided may be provided on a support portion or a substrate for supporting the ink discharge nozzle portion of the recording head. The point is that the temperature at the position where the temperature sensor is provided may be related to the recording head, and the position at which the temperature sensor is provided is not limited if this relationship is satisfied.

The plurality of recording heads of the same color but having different ink densities are not limited to the above-described dark ink recording head and light ink recording head. Is also good. Further, the present invention is also applicable to a printing apparatus using a plurality of printing heads of similar colors and different usage frequencies.

In the above-described embodiment, an example has been described in which the temperature of the ink jet recording head is directly detected. However, the average temperature of each ink jet recording head is detected. For example, the temperature of the recording head unit 9 is detected. Alternatively, the amount of ink recorded by the end nozzles of each inkjet recording head may be controlled according to the detected temperature.

[0064] In the above embodiment, of the nozzles arranged in the recording head 9C ₁ shown in FIG. 6, suppressing the maximum level of the image signal applied only for nozzles 51 located at the extreme end with 54 low Although the the fact, without being limited thereto, including the nozzles in the vicinity thereof and endmost nozzles, for example nozzle 5 of the recording head 9C ₁ shown in FIG. 6
The maximum level of the image signal applied to each of 1 and 52 and 54 and 53 may be kept low.

On the other hand, the present invention brings about an excellent effect particularly in an ink jet recording apparatus which performs recording by forming flying droplets by utilizing thermal energy among ink jet recording systems.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
At least one drive signal corresponding to recorded information and providing a rapid temperature rise exceeding nucleate boiling is applied to the electrothermal transducer disposed corresponding to the sheet or the liquid path holding the liquid. As a result, heat energy is
This causes film boiling on the heat-acting surface of the recording head, and as a result, it is possible to form bubbles in the liquid (ink) in one-to-one correspondence with the drive signal. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned respective specifications, A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses a configuration in which the heat acting portion is arranged in a bending region may be adopted. In addition, Japanese Patent Laid-Open Publication No. Sho 5 discloses a configuration in which a common slit is used as a discharge section of an electrothermal converter for a plurality of electrothermal converters.
Japanese Unexamined Patent Publication No. 9-123670 discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge portion.
A configuration based on JP-A-9-138461 can also be adopted.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by a combination of a plurality of recording heads as disclosed in the above specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition, the print head is exchangeable with a print head of an interchangeable chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. Alternatively, a cartridge type recording head provided with an ink tank may be used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like provided as components of the printing apparatus of the present invention, since the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or sucking means, a preheating means using an electrothermal transducer or another heating element or a combination thereof, and a preparatory means for performing a discharge different from printing on the printhead. Performing the ejection mode is also effective for performing stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and the recording head may be integrally formed or a combination of plural recording heads. The device may be provided with at least one of a multi-color color or a full-color color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or below and which softens at room temperature, or which is liquid, In general, in the ink jet method, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. What is necessary is just to be liquid.

In addition, the temperature rise due to the heat energy can be positively prevented by using it as energy for changing the state of the ink from the solid state to the liquid state, or the ink can be left standing for the purpose of preventing the ink from evaporating. Either using ink that solidifies, or in any case, the ink is liquefied by applying heat energy according to the recording signal, and the ink is ejected as a liquid ink, or the ink that has already started to solidify when it reaches the recording medium. The use of an ink having a property of being liquefied for the first time by heat energy, such as described above, is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or Japanese Patent Application Laid-Open No. 60-71260, while being held as a liquid or solid substance in a porous sheet concave portion or through hole so as to face the electrothermal converter. It is good also as a form. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be provided as an integrated or separate image output terminal of an information processing device such as a word processor or a computer as described above. A copying apparatus combined with a reader or the like, or a facsimile apparatus having a transmission / reception function may be used.

FIG. 10 shows a recording apparatus according to the present invention comprising a word processor, a personal computer, a facsimile apparatus,
FIG. 2 is a block diagram illustrating a schematic configuration when applied to an information processing apparatus having a function as a copying apparatus. In the figure, 201
Is a control section for controlling the entire apparatus, which is provided with a CPU such as a microprocessor and various I / O ports, outputs control signals and data signals to each section, controls signals and data from each section. Control by inputting the data signal. A display unit 202 displays various menus, document information, image data read by the image reader 207, and the like on the display screen. Reference numeral 203 denotes a transparent pressure-sensitive touch panel provided on the display unit 202, and the surface of the display unit 20 is pressed by pressing the surface with a finger or the like.
2, an item input, a coordinate position input, and the like can be performed.

Reference numeral 204 denotes FM (Frequency Mo).
In a sound source section, music information created by a music editor or the like is stored as digital data in a memory section 210 or an external storage device 212, and is read from the memory or the like to perform FM modulation. The electric signal from the FM sound source unit 204 is converted into an audible sound by the speaker unit 205. The printer unit 206 is a word processor,
The recording device according to the present invention is applied as an output terminal of a personal computer, a facsimile machine, and a copying machine.

Reference numeral 207 denotes an image reader for photoelectrically reading and inputting original data, which is provided in the middle of the original conveying path and reads various originals other than facsimile originals and copy originals. Reference numeral 208 denotes an image leader section and 2
A facsimile transmission / reception unit for facsimile transmission of the original data read in step 07 and reception and decoding of the transmitted facsimile signal, and has an interface function with the outside. A telephone unit 209 has various telephone functions such as a normal telephone function and an answering machine function. A ROM 210 stores a system program, a manager program, other application programs, character fonts, a dictionary, and the like, an application program and character information loaded from an external storage device 212, and a video RAM. And the like.

Reference numeral 211 denotes a keyboard section for inputting document information, various commands, and the like. An external storage device 212 uses a floppy disk, a hard disk, or the like as a storage medium.
The external storage device 212 stores character information, music or voice information, user application programs, and the like.

FIG. 11 is an external view of the information processing apparatus shown in FIG. In the figure, reference numeral 301 denotes a flat panel display using a liquid crystal or the like, which displays various menus, graphic information, document information, and the like. A touch panel is provided on the display 301, and a coordinate input or an item designation input can be performed by pressing the surface of the touch panel with a finger or the like. A handset 302 is used when the device functions as a telephone.

The keyboard 303 is detachably connected to the main body.
And various character information and various data can be input. Also, this keyboard 303
Are provided with various function keys 304 and the like. Reference numeral 305 denotes a floppy disk insertion port.

Reference numeral 307 denotes a sheet placing portion for placing a document to be read by the image reader portion 207, and the read document is discharged from the rear of the apparatus. In the case of facsimile reception or the like, recording is performed by the inkjet printer 307.

The display 301 may be a CRT, but is preferably a flat panel such as a liquid crystal display using a ferroelectric liquid crystal. This is because the weight can be reduced in addition to the reduction in size and thickness.

The information processing apparatus is connected to a personal computer.
In the case of functioning as a computer or a word processor, various information input from the keyboard unit 211 in FIG. 10 is processed by the control unit 201 according to a predetermined program, and output as an image to the printer unit 206. When functioning as a receiver of the facsimile apparatus, facsimile information input from the facsimile transmission / reception unit 208 via a communication line is received and processed by the control unit 201 according to a predetermined program, and output to the printer unit 206 as a received image.

When functioning as a copying apparatus, an original is read by an image reader 207, and the read original data is transmitted to a printer 206 via a controller 201.
Is output as a copy image. When functioning as a transmitter of the facsimile apparatus, the image reader unit 207
The document data read by the control unit 201 is transmitted by the control unit 201 according to a predetermined program, and then transmitted to the communication line via the facsimile transmission / reception unit 208.

The information processing apparatus described above may be of an integrated type in which an ink jet printer is built in the main body as shown in FIG. 12. In this case, the portability can be further improved.

Note that, in this figure, parts having the same functions as in FIG. 11 are denoted by the corresponding reference numerals.

By applying the recording apparatus of the present invention to the multifunctional information processing apparatus described above, a high-quality recorded image can be obtained, so that the function of the information processing apparatus can be further improved. Become.

[0089]

As described in detail above, according to the present invention,
Ink recorded by the recording elements at the ends of a plurality of recording heads of the same color and having different ink densities, such as a dark ink recording head and a light ink recording head, according to the temperature of the recording head detected by the head temperature detecting means. Control the amount of black and white stripes on the print medium even when the print head temperature rises due to continuous printing. It can be less noticeable.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment.

FIG. 2 is a schematic perspective view of an example of an ink jet recording apparatus according to the present invention.

FIG. 3 is a shading distribution table.

FIG. 4 is a diagram showing the relationship between input and image density when a light and dark head is used.

FIG. 5 shows a conversion tape for the end nozzle used in the present invention.
Bull.

FIG. 6 is an explanatory diagram of nozzles provided in a recording head.

FIG. 7 is a diagram showing a matrix of image data in the second embodiment.

FIG. 8 is a block diagram of a second embodiment of the present invention.

FIG. 9 is a block diagram of a third embodiment of the present invention.

FIG. 10 is a block diagram showing a schematic configuration when the image recording apparatus of the present invention is applied to an information processing apparatus.

11 is an external view of the information processing apparatus shown in FIG.

FIG. 12 is an external view illustrating another example of the information processing apparatus.

FIG. 13 is a schematic perspective view of an example of an ink jet recording apparatus according to a conventional example.

FIG. 14 is an explanatory diagram of serial scan recording.

FIG. 15 is an explanatory diagram of serial scan recording.

FIG. 16 is a conversion table for a conventional end nozzle.

[Explanation of symbols]

 22 Table ROM for dark and light distribution 25a and 25b γ table ROM 28 Dark ink recording head 29 Light ink recording head 30a and 30b Temperature sensor

Claims (20)

(57) [Claims] 1. An image recording apparatus comprising: a plurality of recording heads having similar colors and different ink densities, wherein each recording head performs image recording using a recording head group having a plurality of recording elements. Temperature detecting means for detecting a temperature related to the recording head, and control means for controlling an amount of ink recorded by a recording element at an end of each of the recording heads in accordance with the temperature detected by the temperature detecting means. An image recording apparatus, comprising: 2. The image recording apparatus according to claim 1, wherein a plurality of recording head groups are provided, each of which has a different color of ink. 3. The image recording apparatus according to claim 1, further comprising a signal dividing unit configured to divide an input image signal into a plurality of signals corresponding to each of the recording heads. 4. The control means converts an input image signal using a γ-table selected from a plurality of γ-tables and drives the printheads, so that the end of each printhead is 2. The image recording apparatus according to claim 1, wherein the amount of ink recorded by the recording element is controlled. 5. The recording head according to claim 1, wherein the recording head ejects ink using thermal energy, and is an inkjet recording head including an electrothermal transducer for generating thermal energy to be applied to the ink. The image recording apparatus according to claim 1. 6. The recording head ejects ink from an ejection port by utilizing a pressure change caused by growth and shrinkage of bubbles caused by film boiling caused by heat energy applied by the electrothermal transducer. Claim 5
The image recording apparatus as described in the above. 7. A copying machine comprising the image recording apparatus according to claim 1 and an image reader section and a control section. 8. A facsimile apparatus comprising: the image recording apparatus according to claim 1; an image reader section, a control section, and a facsimile transmission / reception section. 9. A word processor comprising the image recording apparatus according to claim 1, an input unit, a control unit, and a display unit. 10. A computer comprising: the image recording apparatus according to claim 1; an input unit, a control unit, and a display unit. 11. An image recording apparatus comprising: a plurality of recording heads having similar colors and different ink densities, wherein each recording head performs image recording using a recording head group having a plurality of recording elements; Temperature detecting means for detecting a temperature related to the recording head, and control means for controlling a magnitude of a driving signal given to a recording element at an end of each of the recording heads in accordance with the temperature detected by the temperature detecting means. An image recording apparatus, comprising: 12. An image recording apparatus comprising: a plurality of recording heads of the same color but having different ink densities, wherein each recording head performs image recording using a recording head group having a plurality of recording elements; Temperature detecting means for detecting a temperature related to the recording head of each of the recording heads; a pixel recorded by a recording element at an end of each recording head; and each image given to a recording element corresponding to a pixel recorded around the pixel. Computing means for computing the magnitude of the signal for each recording head in accordance with a predetermined function; and recording at the end of each recording head based on the value obtained by the computing means and the temperature detected by the temperature detecting means. Control means for controlling the amount of ink recorded by the element. 13. The image recording apparatus according to claim 12, wherein said computing means computes the sum of the magnitudes of said image signals for each recording head. 14. The apparatus according to claim 12, wherein said calculating means calculates a sum of respective values obtained by weighting the values of said respective image signals in accordance with the positions of respective pixels. Image recording device. 15. An image recording apparatus comprising: a recording head group having a plurality of recording heads of the same color and having different ink densities for each color; and each recording head having a plurality of recording elements. Temperature detecting means for detecting a temperature related to a group of recording heads, and calculating a magnitude of each image signal corresponding to a pixel recorded by a recording element at an end of each recording head of the recording head group according to a predetermined function. Calculating means for controlling, based on the value obtained by the calculating means and the temperature detected by the temperature detecting means, control means for controlling the amount of ink printed by a printing element at the end of each of the print heads; An image recording apparatus comprising: 16. The image recording apparatus according to claim 15, wherein said calculating means calculates a sum of magnitudes of said image signals. 17. The calculating means weights the value of each image signal according to the ease of bleeding of each color ink on a recording medium, and calculates the sum of the obtained values. The image recording device according to claim 15. 18. An image recording apparatus comprising: a plurality of recording heads having different colors of use of similar colors, wherein each recording head performs image recording using a recording head group having a plurality of recording elements; Temperature detecting means for detecting a temperature related to the recording head, control means for controlling an amount of ink recorded by a recording element at an end of each recording head according to the temperature detected by the temperature detecting means, An image recording apparatus comprising: 19. The image recording apparatus according to claim 18, wherein the plurality of recording heads have different amounts of ink recorded by the respective recording heads due to different use frequencies. 20. An image recording apparatus comprising: a plurality of recording heads of similar colors and different ink densities, wherein each recording head performs image recording using a recording head group having a plurality of recording elements; Temperature detection means provided in the ink supply path, control means for controlling the amount of ink recorded by the recording element at the end of each recording head according to the temperature detected by the temperature detection means, An image recording apparatus comprising: