JPH08267733A - Ink jet printer - Google Patents

Abstract

PURPOSE: To prevent degradation in print quality due to change of recording mode by equalizing print dot densities in the scanning direction in at least two recording modes. CONSTITUTION: Ink discharge by a head 1 to a record medium is controlled by a head drive control section 5. Movement of a carriage 2 to the record medium is controlled by a carriage drive control section 6. A plurality of nozzles arranged in the head 1 wherein the ink is to be discharged are controlled by an address signal from an address generating section 4. A printing data for printing is stored in a record means such as a RAM 7 through an interface 9. These are controlled by a CPU 3 to which they are respectively connected through a bus 11. A control software to be executed by the CPU 3 is stored in a nonvolatile memory means such as a ROM 8 and it can be used by reading out as needed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer having a plurality of recording modes such as a high quality mode and a high speed mode.

[0002]

2. Description of the Related Art In an ink jet printer for recording by irradiating ink as small droplets or particles through a nozzle onto a recording medium such as paper, an apparatus having two recording modes with different printing speeds is known.

Generally, print quality and print quality are known as indices showing the print state. The print quality is related to the formation accuracy of each dot itself. For example, when the speed of the head is high, the accuracy with which the radiated ink lands on the recording medium deteriorates, causing misalignment, which causes The quality will be reduced. In addition, the print quality is an index that represents the formation state of the entire print that is more macro than the print quality, and is related to the dot density. For example, when the dot density is low, the continuity of printing is degraded and a good shape is obtained. Difficult to form.

2 of the conventional inkjet printer
In one recording mode, one storage mode is a mode in which high printing quality is maintained while the printing speed is relatively low (hereinafter referred to as high quality mode), and the other storage mode has a printing quality higher than that of the above recording mode. Inferior, but relatively high printing speed (hereinafter referred to as high speed mode). Therefore, when high print quality is required rather than fast print, the high quality mode is selected, and when higher print speed than good print quality is required, the high speed mode is selected to perform print processing. .

FIG. 7 is a diagram for explaining a recording mode of a conventional ink jet printer. FIG. 7A shows the printing state of the conventional inkjet printer in the high quality mode, and FIG. 7B shows the printing state of the conventional inkjet printer in the high speed mode.

In FIG. 7A, in the conventional high quality mode, for example, the interval between adjacent dots is set to a short La, and the interval required for printing one character (interval of one character in the figure) It is possible to print N dots. In order to perform this high quality mode, the head 1 can be driven N times in the print cycle T0 (sec) during one character interval. Therefore, the printing speed va in this high quality mode is L
It becomes a / T0.

On the other hand, in FIG. 7B, in the conventional high speed mode, for example, the interval between adjacent dots is set to Lb (> La) longer than the interval La in the high quality mode, and one character is printed. During the required interval (interval of one character in the figure), M (less than the number N of high quality modes) (<
N) dots can be printed to reduce the printing density. In order to perform this high-speed mode, the print cycle of the head 1 is set to T0 (sec) during one character interval.
In comparison with the high quality mode, the number of dots is thinned or the number of dots is reduced to enable M times of driving. Therefore, the printing speed vb in the high speed mode is Lb / T0 (> La / T0), which is higher than the printing speed va in the high quality mode.

[0008]

In the conventional ink jet printer, since the dot density of print dots is lowered in order to increase the printing speed, there is a problem that the printing quality is lowered. FIG. 8 is a diagram for explaining the relationship between the recording mode of a conventional inkjet printer and the quality of the inkjet printer. As described above, the print quality is related to the dot density, and when the dot density is low, the continuity of printing is degraded and it becomes difficult to form a good shape. In the high quality mode, when the carriage speed is set to a low speed va, the dot interval is T0 and the dot interval is relatively short La. On the other hand, in the high speed mode, if the carriage speed is set to vb, which is a high speed, the dot interval is T0, so the dot interval is relatively long Lb.
Becomes There is an opposite tendency between the dot interval and the print quality as shown in FIG. 8 (note that the relationship of the print quality shown in the figure shows a general tendency, and the inverse proportion as shown in the figure is not always necessary. However, the print quality is extremely degraded in the high speed mode in which the dot interval is long.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide an ink jet printer which can prevent the deterioration of the printing quality due to the change of the recording mode.

[0010]

SUMMARY OF THE INVENTION The present invention is an ink jet printer having a plurality of recording modes with different printing speeds by ejecting ink to a recording medium for recording, and the scanning direction in at least two recording modes of the recording modes. The above-mentioned object is achieved by the fact that the dot densities of the printing are the same.

Further, according to the present invention, the print control is performed so that the print dot densities are equalized by the discharge control for equalizing the number of print dots in the scanning direction in one character or the discharge control for equalizing the print dot intervals in the scanning direction of the head. It can be performed.

Further, according to the present invention, in an ink jet printer having a plurality of recording modes, recording is performed by ejecting ink onto a recording medium, and a scanning means for relatively scanning the head with respect to the recording medium and a head relative to each other. A head driving unit that drives the head during scanning is provided, the scanning unit causes the head to scan at a scanning speed according to the recording mode, and the head driving unit ejects ink at a time cycle corresponding to the recording mode, In at least two recording modes, the product of each scanning speed and the time period is made constant to achieve the above object.

Further, in the present invention, the plurality of recording modes are provided with energization conditions for driving the head, and the head driving means changes the energization conditions according to the recording modes.

The recording mode in the present invention includes a mode in which the scanning speed of the head is different, such as a high quality mode or a high speed mode, and may further include energization conditions when driving the head.

The scanning in the present invention is an operation of moving the head relative to the recording medium, and the scanning direction is a direction orthogonal to the moving direction of the recording medium itself, and within a certain distance in this scanning direction. The number of dots or the dot distance is constant regardless of the recording mode.

[0016]

When recording on a recording medium by the ink jet printer of the present invention, a desired recording mode is selected from a plurality of recording modes, the head is driven in accordance with the recording mode, and the scanning control of the head itself and the ink are performed. Discharge control is performed. The head prints by ejecting ink at predetermined time intervals while scanning the recording medium. At this time, the scanning speed of the head and the ink ejection cycle are
It is set according to the selected print mode. In at least two print modes among the print modes, the dot densities of the ink ejected onto the print medium are equal.
Ejection control for equalizing the number of print dots in the scanning direction in one character or ejection control for equalizing the print dot intervals in the scanning direction of the head is performed.

As a result, even in the recording modes having different printing speeds, the dot densities of the printings recorded on the recording medium become equal, and the deterioration of the printing quality due to the high speed printing can be prevented.

Further, at this time, by changing the energization condition for driving the head according to the recording mode, it is possible to gradually reduce the deterioration of the print quality caused by the head moving at high speed with respect to the recording medium.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Structure of Embodiment) FIG. 1 is a block diagram for explaining a structure relating to a portion for controlling a head of an embodiment of the present invention. In FIG. 1, a head 1 that ejects ink onto a recording medium is scanned by the carriage 2 with respect to the recording medium. This scanning direction is a direction orthogonal to the moving direction of the recording medium.

The head drive control unit 5 controls the ejection of ink from the head 1 onto the recording medium, and the carriage drive control unit 6 controls the movement of the carriage 2 relative to the recording medium. In addition, the control of the nozzle that ejects ink among the plurality of nozzles included in the head 1 is performed by an address signal from the address generator 4.

The print data for printing is stored in the external device 10
Print data from the RAM via the interface 9
It is stored in a recording means such as 7. These controls are
Each is controlled by the CPU 3 connected via the bus 11. The control software executed by the CPU 3 is RO
It is stored in a non-volatile main memory such as M8, and can be read and used as needed.

Further, data such as each moving speed of the carriage and each energizing condition of the head which are provided in a plurality of recording modes are R
It can be stored in the storage means such as the OM 8 or other RAM (not shown).

Next, the relationship between the head and the storage medium and the printing state in the embodiment of the present invention will be described with reference to FIG. In FIG. 2, the recording medium 12 such as paper is assumed to move intermittently in the direction of arrow A in the figure. Further, the head 1 is moved by the carriage with respect to the recording medium 12 in the direction B orthogonal to the moving direction A and the opposite direction.

The head 1 discharges ink while scanning in the direction of arrow B which is orthogonal to the moving direction A of the recording medium 12 to print a length corresponding to the width of the head in the vertical direction. Be seen. Here, the rectangular frame surrounded by the alternate long and short dash line in the figure represents the area of one character printed by the head, and for example, one character is made to correspond within this one character area for printing. In an inkjet printer, this print is formed by a plurality of dots 13. The dots 13 can be formed by ink droplets ejected from nozzles arranged in the vertical direction of the head 1. The nozzle selection in the vertical direction of the head 1 is selected by the address signal. In addition, 1 of head 1
The horizontal position in the character is determined by the landing position of the ink ejected by the head drive control signal (print signal) input in a predetermined time period while scanning the head 1 in the direction of arrow B by the carriage. Become.

Therefore, the dot density in the scanning direction is
It is determined by the speed of the carriage that scans the head 1 and the ink ejection cycle. Further, this dot density is determined by the number of dots in one character or the dot interval.

(Operation of Embodiment) Next, the operation of the embodiment of the present invention will be described. In the following description, as a plurality of recording modes of the present invention, two recording modes, a high quality mode and a high speed mode, will be described.

In a plurality of recording modes provided in the ink jet printer of the present invention, as in the case of the above-mentioned prior art, a high quality mode in which a high printing quality is maintained while a printing speed is relatively low, and a printing quality is high. Is compared with the high speed mode, which is inferior to the high quality mode but has a relatively high printing speed. The names of the high-quality mode and the high-speed mode are the same as the names in the section of the prior art, but the characteristics of each mode are different as described below. .

FIG. 3 is a diagram for explaining the recording mode of the ink jet printer of the present invention. 3A shows the printing state of the inkjet printer of the present invention in the high quality mode, and FIG. 3B shows the printing state of the inkjet printer of the present invention in the high speed mode.

In FIG. 3A, in the high quality mode of the present invention, for example, the interval between adjacent dots is L, and 1
N dots can be printed during the interval required to print characters (one character interval in the figure). The number of dots N uses the same symbol as the number of dots N used in the section of the related art, but the number of dots is not necessarily the same. In order to perform this high quality mode, the head 1 is moved for a time period T during one character interval.
This can be performed by making it possible to drive N times in 1 (sec). Therefore, the printing speed v1 in this high quality mode is L / T1.

The head is driven by the print signal in the head drive control signal obtained from the head drive control section 5, and the ink is not ejected during one character interval. It can be driven N times. Further, the time period T1 (sec) can be set in accordance with the desired high quality, and can be set to the same value as the time period T0 (sec) in the term of the related art or a different value.

On the other hand, in FIG. 3B, in the high speed mode of the present invention, the interval between adjacent dots is set to the same long L as the interval L in the high quality mode, and the interval required to print one character. It is possible to print N dots in the same number as the number N in the high quality mode during (one character interval in the figure). As a result, the density of dots on the recording medium becomes the same as that in the high quality mode. Then, in order to increase the printing speed in this high speed mode, the time period for driving the head 1 during one character interval is T2 (sec) shorter than the time period T1 (sec) in the high quality mode.
And As a result, the printing speed v2 in this high speed mode becomes L / T2 (> L / T1), and a speed higher than the printing speed v1 in the high quality mode can be obtained.

Therefore, it is possible to obtain a high printing speed while maintaining the same dot density, without performing the processing for reducing the printing quality such as thinning the number of dots or reducing the number of dots as in the conventional high speed mode. it can.

The driving of the head in the high speed mode is also performed by the print signal in the head drive control signal obtained from the head drive control unit 5 as in the high quality mode, and the ink is not ejected. Including the case, it is possible to drive N times during one character interval. The time period T2 (sec) can be set according to the desired printing speed.

Next, the signal relationship between the high quality mode and the high speed mode according to the embodiment of the present invention will be described with reference to the time chart of FIG. FIG. 4A shows a time chart of the high quality mode of the inkjet printer of the present invention, and FIG.
11B shows a time chart of the high speed mode of the inkjet printer of the present invention.

In FIG. 4A, in the high quality mode of the present invention, the head drive control unit 5 supplies a head drive signal (print signal) to the head at a cycle of time interval T1, and the carriage control unit 6 operates. Velocity v corresponding to the period T1
The carriage is scanned at 1 (= L / T1). As a result, the head positions L, 2L, ..., NL become positions corresponding to the head drive signal as shown in FIG.

At this time, energization conditions such as applied voltage and energization time for controlling the ink ejection state of the head are supplied to the head as a head drive signal together with the print signal, and the address signal generator An address signal for selecting a drive nozzle in the head is supplied from the No. 4.

As a result, the head 1 has the dot interval L
In each head position, ink is ejected from the nozzle at a position corresponding to the address signal.

Further, in FIG. 4B, in the high speed mode of the present invention, the head drive controller 5 outputs the head drive signal (print signal) at a cycle of a time interval T2 shorter than the time interval T1 in the high quality mode. In addition, the carriage controller 6 scans the carriage at a speed v2 (= L / T2) higher than that in the high quality mode, corresponding to the cycle T2. As a result, the head positions L, 2L, ..., NL become positions corresponding to the head drive signal, as shown in FIG. Further, this head position reaches the same position in a short time as compared with the high quality mode shown in FIG.

At this time, like the high quality mode,
Energization conditions such as an applied voltage and an energization time for controlling the ink ejection state of the head are supplied to the head as a head drive signal, and the address signal generation unit 4 drives the drive nozzle in the head. An address signal for selection is supplied.

As a result, the head 1 ejects ink from the nozzle at the position corresponding to the address signal at each head position with the same dot spacing L as in the high quality mode.

Therefore, in the high speed mode, the same number of dots are printed at the same one character distance in a shorter time than in the high quality mode, and high speed printing is performed with the dot density kept common.

FIG. 5 is a diagram for explaining the relationship between the recording mode of the ink jet printer of the present invention and the quality of the ink jet printer. In the high quality mode of the present invention, when the carriage speed is set to the low speed v1, the time interval between dots at this time is set to TI and the dot interval is set to L. On the other hand, in the high speed mode, the carriage speed is set to v2 at a high speed, the period between dots is set to T2, and the dot intervals are set to the same L. There is an opposite tendency between the dot interval and the print quality as shown in FIG. 8 (note that the relationship of the print quality shown in the drawing shows a general tendency, and the reverse relation as shown in the drawing does not always exist. However, the print quality is extremely degraded in the high speed mode in which the dot interval is long.

However, in the embodiment of the present invention, since the dot interval can be maintained at a constant value even if the recording mode is changed, the obtained print quality does not deteriorate.

Next, the flow of the printing process in the embodiment of the present invention will be described with reference to the flowchart of FIG.
The data recorded on the recording medium in this printing process is not limited to the print data of the carriage or the like, and includes image data. Step S1: First, in the inkjet printer, it is determined whether or not it is a mode for performing print processing, and in the print processing mode, print processing is performed by the following steps. Step S2: In the case of the print processing mode, it is judged which recording mode is set, and in the case of the high quality mode, the processing of the following steps S3 to S5 is performed, and in the case of the high speed mode. The following steps S6 to S8 are performed. Although two recording modes, a high-quality mode and a high-speed mode, are described here as an example, the number of recording modes is not limited to these two, and a plurality of recording modes can be set.

Step S3: When the high quality mode is set, the high quality mode condition stored in advance in the storage means is read out. These conditions include, for example, carriage velocity V1, dot period T1, head applied voltage V1, and V application time t1.

Steps S4 and S5: Then, the portions of the head drive controller 5 and the carriage drive controller 6 that store the recording mode are cleared, and the conditions of the high quality mode read in step S3 are set.

As a result, the recording mode of the high quality mode can be set.

Step S6: On the other hand, when the high speed mode is set, the high speed mode conditions previously stored in the storage means are read out. The conditions include, for example, carriage velocity V2, dot cycle T2, head applied voltage V2, and V application time t2.

Steps S7 and S8: Then, the portions of the head drive control unit 5 and the carriage drive control unit 6 which store the recording mode are cleared, and the conditions of the high speed mode read in the step S6 are set.

As a result, the recording mode of the high speed mode can be set.

Incidentally, in steps S4, 5, 7, and 8, the storage portion for setting the conditions of the recording mode is replaced with the storage means in the head drive control portion 5 and the carriage drive control portion 6, and is connected to the bus 11 to the primary. It is also possible to use storage means for storage.

Step S9: The printing process is performed according to the conditions set in the above process. This printing process can be performed for each line or page, or for each unit of the print signal sent from the print data, and the recording mode change process can be performed for each unit in the following steps.

Step S10: After the printing processing for each processing unit in the step S9, it is determined whether or not the recording mode is changed. Therefore, when the processing unit is one line, the recording mode can be changed line by line.

The processing unit can be set in comparison with the processing amount of the judgment processing and the subsequent recording mode changing processing on the entire printing processing. The judgment processing and the subsequent recording mode changing processing can be performed. If it becomes a heavy load, it is done in page units or job units.

Step S11: When the recording mode is changed, the currently used storage mode is changed, and the process returns to step S2 and the same processing as described above is performed in the changed recording mode.

Step S12: The step S1
If the recording mode is not changed at 0, step S9
The printing process of is continued until the printing ends due to the end of the print data or the end of the print processing mode.

(Effects of the Embodiment) According to the present invention, by changing the energizing condition for driving the head in accordance with the change of the recording mode, the ink ejection amount, the ejection speed and the like in accordance with the change of the driving cycle of the ink jet printer. It is possible to prevent deterioration of print quality by adjusting the discharge conditions of.

Further, the switching of the print mode during printing is effective in color printing and the like.

(Modification) In the above embodiment, two recording modes, a high-quality mode and a high-speed mode, are described. However, a plurality of printing speeds and energization conditions are provided to set a plurality of modes. can do.

[0060]

As described above, according to the present invention,
It is possible to provide an inkjet printer that can prevent deterioration of print quality due to a change in recording mode.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a configuration relating to a portion for controlling a head according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a head and a storage medium and a printing state according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a recording mode of the inkjet printer of the present invention.

FIG. 4 is a time chart illustrating the signal relationship between the high quality mode and the high speed mode according to the embodiment of this invention.

FIG. 5 is a diagram illustrating the relationship between the recording mode of the inkjet printer of the present invention and the quality of the inkjet printer.

FIG. 6 is a flowchart illustrating a flow of printing processing according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating a recording mode of a conventional inkjet printer.

FIG. 8 is a diagram illustrating a relationship between a recording mode of a conventional inkjet printer and quality of the inkjet printer.

[Explanation of symbols]

 1 head 2 carriage 3 CPU 4 address generator 5 head drive controller 6 carriage drive controller 12 recording medium 13 dots

Claims (4)

[Claims] 1. An inkjet printer having a plurality of recording modes in which ink is ejected onto a recording medium to perform recording and printing speeds are different, and at least two recording modes of the recording modes have the same dot density in the scanning direction. An inkjet printer characterized in that 2. The ink jet printer according to claim 1, wherein the plurality of recording modes have an energization condition for driving a head. 3. An ink jet printer having a plurality of recording modes, wherein ink is ejected onto a recording medium to perform recording, and a scanning unit that relatively scans the head with respect to the recording medium; A head driving unit for driving the head is provided, the scanning unit scans the head at a scanning speed according to the recording mode, the head driving unit ejects ink at a time cycle corresponding to the recording mode, and An ink jet printer characterized in that a product of each scanning speed and a time period is constant in at least two recording modes. 4. The ink jet printer according to claim 3, wherein the head driving unit changes the energization condition according to the recording mode.