JP2001088289A - Ink jet printer and print head therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a stabilized image quality over a long term by appropriately suppressing variation in the ejection characteristics and the dot forming position on a print medium due to use record of a print head. SOLUTION: The ink jet printer comprises means 105, 106 for counting the number of drive pulse being applied to a print head and storing the count accumulated after starting use of the printed along with the record of temperature of the print head measured while being associated with the elapsed time at that temperature. Ink ejection timing of the print head is controlled depending on the stored content (use record of the print head) and ink ejection is controlled by regulating the width of driving pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printing apparatus and a print head for the apparatus.

[0002]

2. Description of the Related Art Conventionally, a recording apparatus (printing apparatus) for performing recording (printing) on a recording medium (hereinafter, also referred to as recording paper or simply paper) such as paper, OHP sheet, etc. A so-called serial type in which a recording head is mounted on a movable portion (hereinafter referred to as a carriage) that reciprocates in a direction (main scanning direction) perpendicular to the transport direction, or recording elements are arranged over a range corresponding to the width of recording paper. There is a line type having a recording head. These recording apparatuses use recording heads based on various recording methods, such as a wire dot method, a thermal method, a thermal transfer method, an ink jet method, and an electrophotographic method.

[0003] Further, a recording apparatus such as these is electrically connected to the recording apparatus via an interface, and instructs editing and recording of information to be recorded by the recording apparatus (which serves as a supply source of image data). Things,
An electronic device or an information processing system including a computer as an information processing device or an image reading device or another form is also widely used.

[0004] Among the above recording apparatuses, an ink jet recording apparatus includes an ink tank for supplying ink as a recording agent, and a recording head for discharging the supplied ink onto recording paper. In many cases, the ink tank is replaced with another ink tank when the ink inside the ink tank is exhausted. In recent years, an ink tank has been fixedly or separably provided integrally with a print head, and a configuration using a print head cartridge in which the print head is replaced when the ink in the ink tank is completely consumed, There is a configuration in which an ink tank is removed from a recording head and can be replaced.

Further, various printings (for example, monochrome printing and color printing) can be performed while appropriately changing recording heads or cartridges having different ink types (for example, black and color), and an optimum printing method according to information to be recorded is provided. Recording apparatuses that can perform recording with a compact configuration have also become widespread.

Further, in the above-described configuration, with respect to a recording agent such as ink consumed in a recording operation, the consumed amount or the amount of ink retained (ink remaining amount) held in an ink tank is used. Some of them can be notified. In addition, when the recording head or the recording material supply means such as an ink tank is replaced, an operation for securing a good recording state prior to recording (so-called ejection recovery processing).
Some implement

In the above-described ink jet recording apparatus, when it is difficult to continue the recording operation during the recording, the recording paper whose recording has been interrupted during the recording may be wasted. It is preferable to stop the recording before it becomes difficult, and to resume the recording after obtaining a state in which the recording is not interrupted in advance. The most common cause of such a state that it is difficult to continue the printing operation during printing is a decrease in the remaining amount of ink. Therefore, it is preferable that the remaining amount of ink is measured as needed, and a warning is issued when the remaining amount has decreased to a predetermined amount, so that the user is urged to refill the ink (such as replacing the ink tank).

[0008]

On the other hand, in recent years, photo printers for realizing so-called photographic image quality have made remarkable progress. However, recording heads used in such printers have been accelerated to have high density and small dots. The recording density is 60
0 to 1200 DPI (dots / inch), and the amount of ejected ink reaches 8 to 4 pl (picoliter). In such a recording head, a subtle change in the ejection characteristics of the ink from the ejection ports appears as streaks, color unevenness, texture, and the like on the recorded image, and these are easily conspicuous. Therefore, if the ejection characteristics change with the lapse of the use period of the head, image deterioration is caused. Therefore, an ink jet element (a heating element in the case of using thermal energy as energy used for ejecting ink,
Even if the nozzle itself including the piezo element does not have an irrecoverable problem,
The service life in image formation is shorter than that of the related art.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described points, and appropriately adjusts the ejection characteristics and the change of the dot formation position on the recording medium (print medium) due to the use history of the recording head (print head). And to maintain a stable image quality for a long period of time.

[0010]

For this purpose, the present invention provides:
In an ink jet printing apparatus for performing printing using a print head for discharging ink, a means for measuring information relating to a use history of the print head, and an ink discharge timing of the print head based on the information relating to the use history And means for controlling

According to the present invention, there is provided an ink jet printing method using a print head for discharging ink, wherein a step of measuring information relating to a use history of the print head, and a step of measuring the information based on the information relating to the use history. Controlling the ink ejection timing of the head.

In these, the print head has a plurality of rows of ejection ports arranged in a direction different from a relative scanning direction with respect to a print medium, and the control means or the step comprises the steps of: Is controlled.

[0013] Further, there is provided a means or a step for performing printing by reciprocatingly scanning the print head with respect to a print medium, wherein the control means or the step controls relative ink ejection timings in forward and backward scans. Can be controlled.

The control means or the step may control the amount of ink ejection by adjusting the energy of a drive signal applied to the print head to eject the ink. The width of the driving pulse can be adjusted.

[0015] The measuring means or step may include means or steps for counting the number of drive signals applied to cause the print head to perform ink ejection.

Alternatively, the measuring means may include means for measuring the temperature of the print head in association with the elapsed time at the temperature.

Alternatively, the measuring means may be means for counting the number of drive signals applied to cause the print head to eject ink, and may measure the temperature of the print head in association with the elapsed time at that temperature. The control unit controls the ink discharge timing of the print head and discharges the ink according to the information related to the use history based on the measurement by the measurement unit. The ink ejection amount can be controlled by adjusting the energy of the applied drive signal.

Further, in the ink jet printing apparatus, there is provided storage means for cumulatively storing the number of the drive signals from the start of use of the print head as information on the use history based on the measurement by the measurement means. be able to.

Alternatively, the inkjet printing apparatus may include a storage unit for storing a temperature history from the start of use of the print head as the information on the use history based on the measurement by the measurement unit.

Alternatively, in the ink jet printing apparatus, the number of the driving signals from the start of use of the print head is cumulatively stored and the temperature history is stored as the information on the usage history based on the measurement by the measuring means. Storage means for storing can be provided.

Further, the present invention has a form of a unit detachable from the ink jet printing apparatus of any of the above forms, and comprises a storage means for storing information relating to the use history based on the measurement by the measuring means. Become a printhead.

Here, the print head may have an electrothermal conversion element that generates thermal energy for causing film boiling of the ink as energy used for discharging the ink.

In this specification, the term "print" means not only the case where significant information such as characters and figures are formed, but also whether the information is significant or insignificant, and is evident so that humans can perceive it visually. Irrespective of whether or not the image is formed, a case where an image, a pattern, a pattern, or the like is widely formed on a print medium or a case where the medium is processed is also referred to.

The term "print medium" refers to not only paper used in general printing apparatuses but also a wide range of cloths, plastic films, metal plates, etc. that can receive ink ejected by the head. Shall be.

Further, "ink" refers to the "print" described above.
Is a liquid that can be applied to a print medium to form an image, a pattern, a pattern, or the like, or to process the print medium.

In the following, the term "nozzle" is a general term for a discharge port, a liquid path communicating with the discharge port, and an element for generating energy used for ink discharge, unless otherwise specified.

[0027]

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

(Example of Configuration of Printing Apparatus) FIG. 1 is a schematic perspective view showing a main part of an embodiment of an ink jet printing apparatus to which the present invention can be applied.

In FIG. 1, a head unit 1 having a plurality (four) of print heads 1A, 1B, 1C, 1D
Is mounted on the carriage 2. Each print head 1
Each of A to 1D has a discharge unit and an ink tank unit, and may be provided with a connector for transmitting and receiving signals and the like for driving the discharge unit.

The plurality of print heads perform printing with inks of different colors, and their ink tanks contain different inks such as black, cyan, magenta, and yellow.
The print head or head unit 1 includes a carriage 2
And a connector holder (electric connection part) for transmitting a drive signal or the like to each print head via the connector on the carriage 2.
Is provided.

The carriage 2 is guided and supported so as to be able to reciprocate along a guide shaft 3 installed in the apparatus main body and extending in the main scanning direction. The carriage 2 is driven by a main scanning motor 4 via a transmission mechanism such as a motor pulley 5, a driven pulley 6, and a timing belt 7, and its position and movement are controlled. A print medium 8 such as a print sheet or a plastic thin plate is conveyed (paper feed) through a position (printing section) opposed to the ejection port surface of the ejection section by rotation of two sets of conveyance rollers 9, 10 and 11, 12. Is done. The print medium 8 has its back surface supported by a platen (not shown) so as to form a flat print surface in the print section. In this case, the respective discharge sections mounted on the carriage 2 are held such that their discharge port surfaces protrude downward from the carriage 2 and are parallel to the print medium 8 between the two pairs of transport rollers. .

Each discharge unit is provided with a discharge heater such as an electrothermal converter that generates thermal energy in response to energization. The thermal energy causes film boiling in the ink, and the printing is performed by discharging the ink from the discharge port using the pressure of the generated bubble.

As described above, in addition to providing the print heads for each color on the integrated head unit 1, the print heads for each color may be independently arranged in parallel. Further, a configuration may be adopted in which a nozzle group that discharges Bk ink and a nozzle group that discharges Y, M, and C inks are arranged side by side in one print head. Further, the number of print heads can be appropriately determined according to the type of color that can be used in the printing apparatus, and an appropriate number can be provided according to not only the color but also the density.

The print head may have a structure in which an ink tank serving as an ink supply source is integrated, or a print head which receives ink supply from an ink tank provided in another part of the apparatus via a tube or the like. Good. When the print head and the ink tank are integrated, the cartridge may be in the form of a cartridge that can be attached to and detached from the apparatus main body (carriage) or the head unit 1. It may be one that can be replaced.

FIG. 2 shows an example of a configuration of a main part of a control system of the printing apparatus shown in FIG. For example, from a host device (which serves as a supply source of image data and can be a computer or an image reading device as an information processing device or another form), the image data 101 is transmitted to a CPU 1
When the signal is input to the CPU 02, a signal is output from the CPU 102 to the head drive control unit 104. The head drive control unit 104 controls the width of the drive pulse applied to the electrothermal transducer (ejection heater) 131 of the ejection unit 103 and the timing of its generation.

The head history measuring unit 105 counts the number of ejection pulses by the pulse generation history measuring unit 151, and correlates the detection information of the temperature sensor 132 provided in the ejection unit 103 with the elapsed time by the temperature history measuring unit 152. Measure. Those pieces of information measured by the head history measurement unit 105 are stored in the pulse generation history storage unit 161 and the temperature history storage unit 162 of the head history storage unit 106, respectively. Then, the head drive control means 10
4 is based on information stored in the head history storage means 106,
The width of the drive pulse applied to the discharge heater 131 and the generation timing thereof are changed and set.

The pulse generation history measuring section 151 of the head history measuring means 105 may have a counter for incrementing the count value in accordance with the discharge heater drive signal. By updating the storage content of the head history storage unit 161 of the storage unit 106, the number of drive signals (equivalent to the number of ejections) since the start of use of the print head can be cumulatively stored. In addition, the temperature history measurement unit 152 of the head history measurement unit 105
May have an A / D converter for converting the output of the temperature sensor 132 provided on the head side into a digital signal, and a calculation unit for performing a calculation described later. The content stored in the temperature history storage unit 162 of the history storage unit 106 can be updated. Further, as the head history storage means 106, a nonvolatile memory such as an EEPROM or a battery-backed-up RAM can be used so that the stored contents can be retained even when the apparatus is turned off.

Further, the temperature sensor 132
May be formed on the substrate in the step of forming the discharge heater 131, or may be in the form of a thermistor attached to the print head. The temperature sensor need not necessarily be hardware as long as the temperature can be estimated based on the driving state of the ejection unit, that is, the energy of the driving pulse, the driving cycle, or the driving frequency. Moreover,
These may be used in combination.

The structure of the ejection section 103 or the head unit 1 will be described with reference to FIG. FIG. 3A shows a configuration example of the head unit 1 and is a schematic diagram viewed from a discharge port side for discharging ink as, for example, droplets. As shown in this figure, two rows of discharge ports 35 are provided for each of the black (Bk), cyan (C), magenta (M), and yellow (Y) color discharge sections. Are arranged in a so-called staggered manner, with their positions shifted in the vertical direction in the figure.

The configuration shown shows a nozzle density of 1200 DPI, and the nozzle arrangement pitch in the sub-scanning direction is about 2 dots.
1.2 μm. The row interval between the two rows of each color is a multiple of the nozzle pitch, and since the ink supply ports 39 are arranged between the discharge port rows as shown in FIG. 3B, the row pitch is about 10 times the nozzle pitch (about 212 μm). It is desirable that

As shown in FIG. 3B, the structure of the discharge section is such that a discharge heater 131 is provided on a substrate 38 on which a supply port 39 is formed. The liquid path 36 and the discharge port 35 are formed by forming a positive resist layer serving as a molding material of a nozzle and a photosensitive resin layer having an ink resistance such as an epoxy resin by a photolithography process or the like. The substrate 38 is supported by the base plate 40.

In the discharge section having such a configuration, for example, Bk
Is formed on the print medium, that is, when the ink is ejected and landed at the same position in the head main scanning direction from the ejection port group of two rows, the ejection of the second nozzle row with respect to the first nozzle row is performed. This can be dealt with by delaying (delaying) the timing by a predetermined amount (10 pixels in this example).

(Correction Corresponding to Head History) FIG. 4 is a schematic cross-sectional view showing the state of the ejection section which has been used for a long time. Since the discharge section having the above-described configuration has a photosensitive resin such as an epoxy resin as a nozzle forming material, the area around the discharge port is slightly deformed by water absorption or liquid absorption during long-term use. When this deformation occurs, the ink is ejected by deviating from the direction perpendicular to the print surface of the print medium by a small angle.

As a result of the inventor's intense study while conducting experiments, it has been found that the deviation of the discharge angle, that is, the dot deviation between the two nozzle rows in each color discharge section can be predicted by the head temperature and the operating time at that temperature. It turned out to be.

FIG. 5 is a diagram for explaining the relationship between the dot shift between nozzle arrays and the elapsed time of use at each temperature based on actual measurement values obtained by experiments. If the adjustment of the ejection timing between the first nozzle row and the second nozzle row of each color ejection unit, that is, the correction of the ejection delay time of the second nozzle row with respect to the first nozzle row, is performed using the relationship as illustrated, It is possible to suppress a dot shift between nozzle rows due to a change in the ejection angle.

However, it has been confirmed by an experiment that a dot shift between nozzle rows has almost no effect on a formed image if the shift is within one pixel (in this example, within 21.2 μm). 1 or 2 before running out
Adjustment of discharge timing (correction of discharge delay time)
Is sufficient. Therefore, in order to simplify the arithmetic processing, the sum of (head temperature T) × (elapsed time t) × (temperature coefficient AT) at each temperature is stored in the storage unit 162 as a temperature history, and when a predetermined threshold is exceeded. Then, the ejection delay time may be corrected by the head drive control unit 104.

Next, a description will be given of a change in ejection characteristics depending on the number of ejection pulses.

In a discharge section such as this example using a discharge heater that generates thermal energy as energy used to discharge ink, discharge characteristics change (especially, due to "burn" generated on the discharge heater). The ink ejection amount and the ejection speed decrease). Therefore, the number of ejection pulses from the start of use is counted by the pulse generation history measurement unit 151 and stored in the pulse generation history storage unit 161, so that the “burn” state on the ejection heater or the ink ejection amount and ejection speed Can be estimated. When the stored number of ejection pulses exceeds a predetermined value, the head drive control unit 104 appropriately sets the energy (pulse width in this example) of the electric signal to be applied to the ejection heater, thereby enabling ejection. Characteristics can be kept stable.

Further, the decrease in the ejection speed is a cause of a shift in dot formation position (so-called ruled line shift when vertical ruled lines are printed in reciprocal printing) particularly when printing is performed in reciprocating main scanning. Become.

FIG. 6 is a schematic diagram for explaining the occurrence of such a ruled line shift. FIG. 11A shows the initial state, and FIG.
Assuming that the recording density of 00 DPI is driven at 15 KHz, the ejection speed (v) of the ink droplet 100 ejected from the ejection port 35 of the ejection unit 103 is 15 m / s, the distance between the ejection port 35 and the print medium is 1 mm, Is a state in which the main scanning speed is 0.318 m / s. X0 in FIG. 9A is the amount of movement in the main scanning direction from the application of the ejection pulse to the arrival of the ink droplet on the print medium. In this initial state, X0 = 21.2 μm. When reciprocating printing is performed by the inkjet head, the delay time of reciprocating printing is determined in consideration of the value of X0.

On the other hand, FIG. 6B shows reciprocating printing in a state where the ejection speed (v) is reduced to 10 m / s by the head history. In this case, the ink droplet is applied to the print medium after the ejection pulse is applied. Is reached in the main scanning direction X1 = 31.8 μm. As a result, the dot formation position in the forward main scan and the dot formation position in the backward main scan are shifted by 2 × (31.8-21.2) = 21.2 μm.

Accordingly, if the delay time in the reciprocating printing is appropriately corrected according to the pulse generation history, the occurrence of such a shift can be suppressed and a stable image can be formed.

(Example of implementation of history storage means)
The head history storage means may be provided on the printing apparatus main body side to refresh the contents when the head unit 1 is replaced, but the following configuration may be adopted.

FIG. 7 shows another example of the configuration of the head unit 1, and the discharge unit 10 in which a discharge heater, a discharge port and the like are formed.
3, a flexible cable 110 electrically connected to the discharge heater, and a chip tank 1 in which an ink supply path from an ink tank unit (not shown) to the discharge unit 103 is formed.
And 12. At the end of the flexible cable 110, there is provided a contact pad 113 for making an electrical connection with the printing apparatus main body by making contact with a connection provided on the carriage. EEPROM 63 is mounted. Although the drawing shows the EEPROM 63 provided on the same side surface as the contact pad 113, if it is mounted on the back surface side, it is not necessary to provide a relief when the head unit 1 is mounted on the printing apparatus main body or the carriage. .

By providing the EEPROM 63 as the head history storage means 106 on the head unit 1 side, information specific to the ejection unit 103 or the head unit 1, that is, its own configuration, initial drive control timing, and the like can be stored in the printing apparatus. To make an adjustment and obtain an appropriate driving state. In addition, even if the continuously usable head unit 1 is temporarily replaced with another unit and re-attached according to the image to be formed or the operator's desire, the stored contents are retained, so that the head unit 1 can be appropriately handled. Becomes

(Example of Control According to Head History) FIG. 8 is a flow chart showing an example of a control procedure for correcting the head drive timing according to the head history. Alternatively, it can be started at an appropriate timing, such as when a predetermined amount of printing is performed, when the head unit is replaced, or the like.

When this procedure is started, first, in step S1
At the temperature history storage unit 162 or the EEPROM 63
The data related to the temperature history stored in the memory is read. Next, in step S3, it is determined whether or not the read temperature history data exceeds a predetermined value. If the determination is affirmative, the ejection delay time of the second nozzle row with respect to the already set first nozzle row is corrected. Is performed (step S5).

Next, in step S7, data relating to the pulse generation history (the number of discharge pulses (number of discharges since the start of use)) stored in the pulse generation history storage unit 161 or the EEPROM 63 is read. Next, in step S9, it is determined whether or not the read number of discharge pulses exceeds a predetermined value. If the determination is negative, this procedure is terminated. If the determination is affirmative, the electric signal applied to the discharge heater is determined. The energy (pulse width in this example) is reset to an appropriate value so that a stable ejection amount can be obtained (step S11).

In step S13, it is determined whether or not reciprocal printing is to be performed. If the determination is affirmative, the ejection timing between reciprocal printings is appropriately corrected in accordance with the pulse generation history, and the deviation between reciprocal printings is determined. Is suppressed (step S15).

In the above description, the delay time of the second nozzle row with respect to the first nozzle row is corrected in step S5 in accordance with the temperature history for the head unit 1 having the discharge section having two nozzle rows for each color. However, it goes without saying that the correction target can be appropriately determined according to the configuration of the head unit. For example, if there are three or more nozzle arrays, the relationship may be corrected according to the temperature history. Also, depending on the configuration of the print head, such as the material for forming the ejection sections, one or two ejection sections corresponding to a plurality of colors (colors, densities, etc.)
The relationship between the nozzle rows provided above may be corrected according to the temperature history. Further, if the temperature can be detected for each nozzle or for each of a predetermined number of nozzle groups, the temperature history can be stored and corrected in units of those.

Further, the correction of the energy (pulse width) of the electric signal applied to the discharge heater according to the pulse generation history (step S11) and the correction of the discharge timing between the reciprocating printing (step S15) are performed.
Considering that color printing or the like is performed by superimposing a plurality of types of ink on the same position, not only the relationship in the same ejection unit but also a correction in accordance with the pulse generation history may be performed between a plurality of ejection units. Also in this case, the pulse generation history may be stored and corrected for each nozzle or each predetermined number of nozzle groups.

In the above example, the discharge timing between the nozzle rows is determined based on the pulse generation history and the temperature history.
Although the ejection timing and the energy (pulse width) of the drive signal between the reciprocal printing are controlled, any one of them can be selectively used according to the configuration of the print head and other needs.

FIG. 9 shows an example of a drive circuit of the ink jet print head which realizes the control of FIG. This drive circuit is roughly divided into a transistor array section for turning on / off a current, and a control section for managing on / off timing and data of the transistor array section. In addition, the transistor array unit includes a discharge heater 10041 of the first nozzle row and a discharge heater 1004 of the second nozzle row.
Transistor 100 for supplying a large current to
51 and 10052. The control unit controls the AND circuits 10031 and 10032 and the print buffers 10021 and 1001 for each nozzle row.
0022 and shift registers 10011 and 1001
And 2.

In order to receive print data, a signal line for transmitting signals IDATA-1 and IDATA-2 and a signal line for transmitting clock signal DCLK are connected to the control unit. Print data is IDATA-1, ID
The data is transferred as ATA-2 and stored in the shift register at the rising edge of DCLK. The print data is sequentially transferred to the storage element in synchronization with the rise of the continuously input signals IDATA-1 and IDATA-2.

Then, print data is formed in the shift registers 10011 and 10012 by giving rises of the DCLK signal for the number of nozzles (256 in this embodiment) of each nozzle row and print data synchronized with the rise. . Shift registers 10011 and 1001
2 is a print buffer 10021,
10022 and the shift register 10011,1
0012 is ready to receive the next print data. Data transfer from the shift registers 10011 and 10012 to the print buffers 10021 and 10022
It is started by the BG signal. At the rising edge of the BG signal, the print data of the shift register is transferred to the print buffer.

The print data transferred to the print buffer includes signals HEAT-1 and HEAT-2 for performing time control for energizing the discharge heaters 10041 and 10042.
Are ANDed by AND circuits 10031 and 10032 with each other.
51, 10052. Discharge heater 100
41, 10042 are transistors 10051, 100
In accordance with ON / OFF of 52, heat is generated.

FIGS. 10A and 10B are timing charts of signals of the drive circuit of FIG. FIG. 10 (A)
At the second timing with respect to the ejection timing of the first nozzle row.
The delay time t1 of the ejection timing of the nozzle row is determined by calculation in the CPU 102 shown in FIG. Based on this, signals HEAT-1, HEAT-2 are sent to the print head.

FIG. 10B shows a state where the delay time is changed by the temperature history from the state of FIG.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, among ink jet printing methods. An excellent effect is obtained in a print head and a printing apparatus of a system in which a change in the state of ink is caused by the thermal energy. This is because such a method can achieve higher density and higher definition of the print.

The typical structure 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 is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. Applying at least one drive signal corresponding to the printing information and providing a rapid temperature rise exceeding nucleate boiling, causing the electrothermal transducer to generate thermal energy, causing film boiling on the heat-acting surface of the printhead. This is effective because bubbles can be formed in the liquid (ink) corresponding to this drive signal on a one-to-one basis. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. 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. If the conditions described in U.S. Pat. No. 4,313,124 relating to the rate of temperature rise of the heat acting surface are adopted, more excellent printing can be performed.

The structure of the print head is a combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angle liquid flow path) as disclosed in the above-mentioned respective specifications.
In addition, the present invention also includes a configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600 which disclose a configuration in which a heat acting portion is arranged in a bending region. That is, according to the present invention, printing can be performed reliably and efficiently regardless of the form of the print head.

Further, the present invention can be effectively applied to a full line type print head having a length corresponding to the maximum width of a print medium that can be printed by a printing apparatus. Such a print head may have a configuration that satisfies the length by combining a plurality of print heads, or a configuration as a single print head that is integrally formed.

In addition, even in the case of the serial type as described above, a print head fixed to the apparatus main body, or an electric connection with the apparatus main body or ink from the apparatus main body by being mounted on the apparatus main body. The present invention is also effective when a replaceable chip-type print head that can be supplied or a cartridge-type print head in which an ink tank is provided integrally with the print head itself is used.

It is preferable to add a print head discharge recovery means, a preliminary auxiliary means, and the like as the configuration of the printing apparatus of the present invention, since the effects of the present invention can be further stabilized. If you list these specifically,
Pre-heating means for heating using a capping means, a cleaning means, a pressure or suction means, an electrothermal converter or another heating element or a combination thereof for the print head, Pre-discharge means for performing another discharge can be given.

The type and number of print heads to be mounted are, for example, one for each single color ink.
In addition to those provided with only a plurality of inks, a plurality of inks may be provided corresponding to a plurality of inks having different print colors and densities. That is, for example, the print mode of the printing apparatus is not limited to the print mode of only the mainstream color such as black, but may be any of a print head integrally formed or a combination of a plurality of print heads. The present invention is also very effective for an apparatus provided with at least one of the full-color print modes using mixed colors.

In addition, in the embodiment of the present invention described above, the ink is described as a liquid.
An ink that solidifies at room temperature or below and softens or liquefies at room temperature may be used, or the ink jet method controls the viscosity of the ink by adjusting the temperature of the ink itself within the range of 30 ° C to 70 ° C. In general, the temperature is controlled so that is within the stable ejection range, and therefore, a liquid in which the ink is in a liquid state when the use print signal is applied may be used. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of heat energy according to the print signal and the liquid ink to be ejected, or to start solidifying when it reaches the print medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. 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, the form of the ink jet printing apparatus according to the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. And the like.

[0078]

As described above, according to the present invention,
It is possible to suppress the change in the ejection characteristics and the dot formation position on the print medium due to the use history of the print head. Therefore, when forming a high-definition image such as a photographic image, the image forming life is extended without generating streaks or color unevenness that can be particularly conspicuous, and a high-quality image is produced until the life of the print head itself is exhausted. It can be formed stably.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating a main configuration of an embodiment of an inkjet printing apparatus to which the present invention can be applied.

FIG. 2 is a block diagram illustrating a configuration example of a main part of a control system of the printing apparatus illustrated in FIG. 1;

3A and 3B are diagrams for explaining a configuration example of a head unit used in the configuration of FIG. 1; FIG. 3A is a schematic diagram of the head unit viewed from a discharge port side; FIG. 3B is a schematic cross section of a discharge unit; FIG.

FIG. 4 is a schematic cross-sectional view for explaining a discharge state of a discharge unit having a long use time.

FIG. 5 is a diagram for explaining a relationship between a dot shift between nozzle arrays in a discharge unit and a use elapsed time at each temperature.

FIGS. 6A and 6B are diagrams for explaining a mode in which a drop in ink ejection speed due to a head usage history causes a shift in dot formation positions during reciprocal printing, wherein FIG.
(B) is a schematic diagram showing reciprocating printing in a state where the ejection speed is low.

FIG. 7 is a perspective view showing another configuration example of a head unit to which the present invention can be applied.

FIG. 8 is a flowchart illustrating an example of a control procedure for correcting a head drive timing according to a head history.

FIG. 9 is a circuit diagram illustrating an example of a drive circuit of an ink jet print head that implements the control of FIG. 8;

FIGS. 10A and 10B are timing charts of signals of the drive circuit of FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 head unit 1A to 1D print head 2 carriage 8 print medium 35 ink discharge port 36 liquid path 38 substrate 39 supply port 40 base plate 63 EEPROM 102 CPU 103 discharge section 104 head drive control means 105 head history measurement means 106 head history storage means 131 Discharge heater 132 Temperature sensor 151 Pulse generation history measurement unit 152 Temperature history measurement unit 161 Pulse generation history storage unit 162 Temperature history storage unit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C056 EA07 EA08 EB07 EB30 EB49 EC03 EC07 EC37 EC42 EC72 EC77 FA03 FA11 HA52 2C057 AF31 AF32 AG15 AG16 AL25 AL40 AM03 AM15 AM19 AM21 AN02 AP02 AP47 BA03 BA13 DA09 DB01 DC02 DD06 DD09 DE02 DE

Claims (19)

[Claims] 1. An ink jet printing apparatus for performing printing using a print head for discharging ink, comprising: means for measuring information relating to the use history of the print head; and performing the printing based on the information relating to the use history. An ink jet printing apparatus comprising: means for controlling ink ejection timing of a head. 2. The print head has a plurality of rows of discharge ports arranged in a direction different from a relative scanning direction with respect to a print medium, and the control means controls ink discharge timing among the plurality of rows. The inkjet printing apparatus according to claim 1, wherein: 3. A printing apparatus comprising: means for causing the print head to reciprocately scan a print medium to perform printing; wherein the control means controls relative ink ejection timing during forward and backward scanning. The inkjet printing apparatus according to claim 1, wherein: 4. The ink-jet apparatus according to claim 1, wherein the control unit controls the amount of ink discharge by adjusting the energy of a drive signal applied to the print head to discharge the ink. Printing device. 5. The ink jet printing apparatus according to claim 4, wherein said control means adjusts a width of a driving pulse applied to said print head. 6. An ink jet printing apparatus according to claim 1, wherein said measuring means includes means for counting the number of drive signals applied to cause said print head to perform ink ejection. 7. The ink jet printing apparatus according to claim 1, wherein said measuring means has means for measuring the print head temperature in association with the elapsed time at the temperature. 8. The measuring means for counting the number of drive signals applied to cause the print head to perform ink discharge, and measuring the print head temperature in association with the elapsed time at the temperature. Having means to
The control unit controls the ink ejection timing of the print head according to the information on the use history based on the measurement by the measurement unit, and controls the energy of a drive signal applied to the print head to cause the ink to be ejected. 2. The ink jet printing apparatus according to claim 1, wherein the ink ejection amount is controlled by adjusting the ink ejection amount. 9. A storage unit for cumulatively storing the number of drive signals from the start of use of the print head as information on the use history based on the measurement by the measurement unit. The inkjet printing apparatus according to claim 6. 10. The apparatus according to claim 7, further comprising storage means for storing a temperature history from the start of use of the print head as information on the use history based on the measurement by the measurement means. Inkjet printing equipment. 11. A storage unit for cumulatively storing the number of drive signals from the start of use of the print head and storing a temperature history as information on the use history based on the measurement by the measurement unit. The inkjet printing apparatus according to claim 9, further comprising: 12. A storage unit which has a form of a unit detachable from the inkjet printing apparatus according to claim 1, and stores information relating to the use history based on measurement by the measurement unit. A print head, characterized in that: 13. The print head according to claim 12, further comprising an electrothermal conversion element that generates thermal energy for causing film boiling of the ink as energy used for ejecting the ink. 14. An ink jet printing method using a print head for discharging ink, wherein: a step of measuring information relating to a use history of the print head; and an ink discharge of the print head based on the information relating to the use history. An ink-jet printing method, comprising a step of controlling timing. 15. The print head has a plurality of rows of ejection ports arranged in a direction different from a relative scanning direction with respect to a print medium, and the control step controls ink ejection timing between the plurality of rows. The inkjet printing method according to claim 14, wherein: 16. The printing method according to claim 16, further comprising a step of causing the print head to perform reciprocal scanning on a print medium to perform printing, wherein the controlling step controls relative ink ejection timing during forward and backward scanning. The ink-jet printing method according to claim 14, wherein: 17. The ink-jet apparatus according to claim 14, wherein the control step controls an ink ejection amount by adjusting energy of a drive signal applied to the print head to eject the ink. Printing method. 18. The ink-jet printing method according to claim 17, wherein the control step adjusts a width of a drive pulse applied to the print head. 19. The ink-jet printing method according to claim 14, wherein the measuring step includes a step of counting the number of drive signals applied to cause the print head to perform ink ejection.