Inkjet printer and inkjet printer controlling method

An inkjet printer includes: a recording head which includes jet openings for jetting ink; a sensor for detecting a jet opening causing jetting failure among the jet openings; a sucking mechanism for sucking the ink from each jet opening; a comparing section for comparing number of the detected jet opening causing jetting failure with predetermined number; and a control section for performing a sucking process where the sucking mechanism performs a sucking operation, for performing an examination process to count the jet opening causing jetting failure by the detection of the sensor and by simulated jetting of each jet opening, for performing a comparing process where the comparing section performs a comparing operation after the examination process, and for re-performing the examination process without performing the sucking process when judged in the comparing process that the number of the jet opening causing jetting failure is more than the predetermined number.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inkjet printer and a controlling method thereof, the inkjet printer comprising a recording head for jetting ink from a plurality of jet openings, a sensor for examining jetting failure with respect to each jet opening of the recording head, and a sucking mechanism for sucking ink from each jet opening of the recording head.

2. Description of Related Art

An inkjet printer which forms an image on recording medium by jetting ink toward the recording medium from each jet opening provided in a recording head has been in practical use. Since an inkjet printer records an image by jetting ink from each jet opening of a recording head, among a plurality of jet openings, there are normal jet openings which normally jet ink and jetting openings which do not jet ink due to jetting failure. There are roughly two reasons which cause jetting failure. The first reason is generation of air bubble within a channel which is a passage to the jet opening. The second reason is clogging of ink at a jet opening where ink existing within the channel which is a passage to the jet opening gets more viscous or solidified when the recording head is left unused for a long period.

In order to recover from jetting failure of ink, an inkjet printer comprises a cleaning mechanism for cleaning the recording head. The cleaning mechanism is used to eliminate ink adhering around each jet opening by contacting a cap member to the recording head, sucking the ink from each jet opening of the recording head while making a sucking pump generate a sucking force to the cap member, and wiping the recording head with a wiper blade after the sucking.

In order to deal with the above-mentioned situation where the recording head is left unused for a long period, what is developed is one in which when a predetermined period passes since a certain timing, a cleaning mechanism automatically functions for performing the sucking of ink and the wiping of recording head (for example, see JP-Tokukai-2002-79693A).

Further, what is also developed is one in which a examining unit examines whether each of jet opening of the recording head is in a jetting failure state, prior to the sucking of ink and the wiping of recording head by the cleaning mechanism (for example, see JP-Tokukai-2002-79693A and JP-Tokukaihei-3-244546A). In the inkjet printer disclosed in the JP-Tokukai-2002-79693A, simulated jetting which jets ink without involving image recording is performed with respect to each jet opening in the recording head, and the examining unit examines whether there is ink jetting with respect to each jet opening and if the recording head has a jet opening causing jetting failure according to the examination result, the cleaning mechanism sucks ink and wipes the recording head, and on the contrary, if the recording head has no jet opening causing jetting failure, the cleaning head does not suck ink or wipe the recording head.

In the inkjet printer disclosed in JP-Tokukaihei-3-244546A, the examining unit examines whether there is ink jetting with respect to each jet opening and if the recording head has no jet opening causing jetting failure according to the examination result, image recording is performed without making the cleaning mechanism suck ink nor wipe the recording head. On the contrary, if the recording head has a jet opening causing jetting failure according to the examination result, the inkjet printer repeats the sucking of ink and the wiping of recording head by the cleaning mechanism until the examining unit detects no jet opening causing jetting failure.

However, even after the sucking of ink and the wiping of recording head are performed, there is a possibility of existence of a jet opening causing jetting failure. In particular, there is a case where a jet opening which is capable of jetting ink normally before the sucking of ink and the wiping of recording starts causing jetting failure after the sucking of ink and the wiping of recording head.

Further, as another method to recover from jetting failure of ink, there is a method to forcibly suck ink from each jet opening of the recording head. One example of such method is disclosed in JP-Tokukaihei-5-293968A. The method of JP-Tokukaihei-5-293968A makes the recording head perform the simulated jetting, measures temperature inside of the recording head at three moments which are: before the simulated jetting; right after the simulated jetting; and after predetermined period has passes since the simulated jetting, judges whether there is jetting failure according to a temperature variation among these three moments, and performs a process to recover from the jetting failure of the recording head by sucking ink from each jet opening of the recording head if it is judged that there is jetting failure.

However, with the method of JP-Tokukaihei-5-293968, ink is sucked always with a constant sucking force regardless of whatever cause of jetting failure (even if a cause of jetting failure is generation of air bubble or clogging of foreign material). Therefore, a recovering process corresponding to a cause of jetting failure is not performed, whereby there is inconvenience in conjunction with the recovering process. In other words, if a cause of jetting failure is generation of air bubble, it is possible to eliminate the air bubble with a comparatively low sucking force. However, in the case of sucking ink always at a certain sucking force more than the sucking force necessary for eliminating air bubble, ink which is not necessary for eliminating air bubble (ink which can be used for image recording) is to be uneconomically sucked, whereby it is ink wasting. On the other hand, if a cause of jetting failure is clogging of foreign material, it is necessary to have a comparatively high sucking force. If ink is sucked with a certain sucking force which is less than the sucking force necessary for eliminating foreign material, it is not possible to eliminate the foreign material.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-mentioned problems, that is, to reduce the possibility of causing jetting failure. Another object of the present invention is to recover from jetting failure in correspondence with a cause of jetting failure.

In accordance with a first aspect of the present invention, an inkjet printer comprises: a recording head which comprises a plurality of jet openings for jetting ink; a sensor for detecting a jet opening causing jetting failure among the plurality of jet openings of the recording head; a sucking mechanism for sucking the ink from each jet opening of the recording head; a comparing section for comparing number of the jet opening causing jetting failure detected by the sensor, with predetermined number; and a control section for performing a sucking process in which the sucking mechanism performs a sucking operation, for performing an examination process to count the jet opening causing jetting failure by making the sensor detect the jet opening causing jetting failure and by making each jet opening of the recording head perform simulated jetting, for performing a comparing process in which the comparing section performs a comparing operation after the examination process, and for re-performing the examination process without performing the sucking process when it is judged in the comparing process that the number of the jet opening causing jetting failure is more than the predetermined number.

In accordance with a second aspect of the present invention, a method for controlling an inkjet printer comprising a recording head which comprises a plurality of jet openings for jetting ink, a sensor for detecting a jet opening causing jetting failure among the plurality of jet openings of the recording head, a sucking mechanism for sucking the ink from each jet opening of the recording head, and a control device for controlling operations of the sucking mechanism and the recording head, comprises: making the sucking mechanism perform a sucking operation; counting number of the jet opening causing jetting failure by making the recording head perform simulated jetting from each jet opening and by counting up the number when the jet opening causing jetting failure is detected by the sensor, after the sucking operation is performed; and comparing the counted number of the jet opening causing jetting failure with predetermined number, after the counting of the number, wherein when it is judged in the comparing that the number of the jet opening causing jetting failure is more than the predetermined number, the counting of the number is performed without performing the sucking operation.

Here, in regard to the printer and the controlling method thereof of the first and second aspects of the present invention, investigation was made on the transition with time of jet openings causing jetting failure which emerge in a recording head after ink is sucked from each jet opening of the recording head and the recording head is wiped. Its result is shown inFIG. 1. InFIG. 1, the horizontal axis indicates unused time (minutes) which has passed since the sucking process and wiping process are performed to the recording head, and the vertical axis indicates the number of jet openings causing jetting failure existing in the recording head. As shown inFIG. 1, it is easier to have jet openings causing jetting failure right after the sucking process and wiping process, and the time passes by, there is a tendency of reducing the number of jet openings causing jetting failure. In consideration of such tendency, in accordance with the printer and the controlling method thereof of the first and second aspects of the present invention, an examination process which counts the number of jet openings causing jetting failure is performed after the sucking process is performed, wherein if the number of jet openings causing jetting failure exceeds predetermined number, what is performed is not the sucking process again, but the examination process repeatedly. Thereby while the examination process is being repeated, the number of jet openings causing jetting failure is reduced.

According to the printer and the controlling method thereof of the first and second aspects of the present invention, an examination process which counts the number of jet openings causing jetting failure is performed after the sucking process is performed, wherein if the number of jet openings causing jetting failure exceeds predetermined number, the examination process is repeatedly performed. Therefore, while the examination process is being repeated, the number of jet openings causing jetting failure is reduced, whereby it is possible to reduce the possibility of causing jetting failure.

In accordance with a third aspect of the present invention, an inkjet printer comprises: a recording head which comprises a plurality of jet openings for jetting ink; a sensor for detecting a jet opening causing jetting failure among the plurality of jet openings of the recording head; a cleaning mechanism for cleaning the recording head; and a control section for making the sensor detect the jet opening causing jetting failure by making the recording head perform simulated jetting from each jet opening, for performing an examination process to count number of the jet opening causing jetting failure, for performing a cleaning process to make the cleaning mechanism perform a cleaning operation after the examination process is performed, for performing a second examination process which is identical to the examination process after the cleaning process is performed, for performing a judging process to judge whether the number of the jet opening causing jetting failure counted in the second examination process is not less than predetermined number after the second examination process is performed, and for determining a cleaning mode of the cleaning process which is performed after the judging process according to a result of the judging process.

According to the printer of the third aspect of the present invention, the control device performs two times of examination processes, which are the examination process and the second examination process. Therefore, it is possible to judge whether a jet opening causing jetting failure is common or not between before and after the sucking mechanism performs the sucking operation, whereby, according to the judgment result, it is possible to judge whether the cause of the jetting failure is generation of air bubble or clogging of foreign material. In other words, it is possible to judge that, if the jet opening causing jetting failure is common, the cause of the jetting failure is generation of air bubble, and if the jet opening causing jetting failure is not common, the cause of the jetting failure is clogging of foreign material. Then, after the second examination process, the sucking mechanism is actuated under a sucking mode being different from a sucking mode before the second examination process. Therefore, it is possible to change a sucking mode of the sucking mechanism according to a cause of jetting failure (whether generation of air bubble or clogging of foreign material). Further, according to the change of a sucking mode of the sucking mechanism based on the detection result by the sensor, it is possible to recover a jet opening according to a cause of jetting failure.

PREFERRED EMBODIMENTS OF THE INVENTION

Hereinafter, the best mode for implementing the present invention will be described with reference to figures. However, although technically preferable various limitations are applied to an embodiment described hereafter for implementing the present invention, the scope of the invention is not limited to the embodiment hereafter or the illustrated examples.

FIG. 2is a perspective view of an inkjet printer1to which the present invention is applied.FIG. 3is a side view showing a recording head7, an ink receiving unit31and a sucking examination sensor32each of which is provided in the inkjet printer1.FIG. 4is a side view showing the recording head7and a cleaning unit40provided in the inkjet printer1.FIG. 5is a block diagram showing a control device60provided in the inkjet printer1.

As shown inFIG. 2, the inkjet printer1comprises a platen2. The platen2is formed in a plate shape, and is used for supporting a recording medium99which has a sheet form, from underneath. Conveyance rollers3and4are respectively placed at the front and back of the platen2, and the shaft center of the conveyance rollers3and4is placed in parallel with an upper surface of the platen2. A conveyance motor11(seeFIG. 5) is connected to the conveyance rollers3and4to be a driving force, so that when the conveyance motor11drives the conveyance rollers3and4to rotate around the shaft center, the recording medium99set to the conveyance rollers3and4is conveyed along a conveyance direction A. Here, the conveyance direction A is a direction being orthogonal to the shaft center of the conveyance roller3and4.

InFIG. 2, a guide member5is placed above the platen2. The guide member5is provided approximately in parallel with the upper surface of the platen2, and further in orthogonal to the conveyance direction A. This longitudinal direction along which the guide member5is provided is a scanning direction B. The guide member5supports a carriage6. A carriage motor12(seeFIG. 5) drives the carriage6to move back and forth along the scanning direction B in a state of being guided by the guide member5.

The carriage6comprises four recording heads7to10for jetting ink of each process colors of yellow (Y), magenta (M), cyan (C) and black (K) respectively, toward a recording surface of the recording medium99. These recording heads7to10are arranged at even intervals along the scanning direction B. These recording heads7to10are moved with the carriage6back and forth along the scanning direction B.

A plurality of jet openings (illustration omitted) are formed on each of bottom surfaces7ato10aof the recording heads7to10(surfaces facing to the platen2), so that each of the recording heads7to10jets ink as droplet from these jet openings. In other words, each of the bottom surfaces7ato10aof each of the recording heads7to10is an ink jetting surface. In each of the recording heads7to10, jet openings of ink are arranged so as to make one line or a plurality of lines along the conveyance direction.

Here, four ink tanks for storing ink of each of the process colors of Y, M, C and K respectively are connected to each of the recording heads7to10through a flexible tube which is capable of following the back-and-forth movement of the carriage6. Ink is supplied to the four recording heads7to10from each ink tank through the flexible tube with respect to each color.

Further, the inkjet printer1comprises a recovering unit20for recovering each of the recording heads7to10from jetting failure. The recovering unit20is placed below the recording heads7to10and the carriage6, and at the left side of the platen2.

The recovering unit20comprises an simulated jetting unit30which is placed at a location to perform simulated jetting, which jets ink without involving image recording, and a cleaning unit40for cleaning the recording heads7to10. As shown inFIG. 2andFIG. 3, the simulated jetting unit30comprises an ink receiving unit31for receiving ink which is jetted each of the recording heads7to10according to simulated jetting, and a jetting examination sensor32for examining whether ink is jetted from each jet opening on the bottom surfaces7ato10aof the recording heads7to10.

The ink receiving unit31is provided in a rectangular solid box shape so as to have the upper surface opened, and is located next to the platen2to the left. Here, an ink receiving unit composed of spongy ink absorbing material may be placed instead of the box-like ink receiving unit31, or the ink receiving unit31may incorporate therein spongy ink absorbing material.

In the proximity of the ink receiving unit31, the jetting examination sensor32is placed. The jetting examination sensor32comprises a light emitting element33and a light receiving element34. The light emitting element33is placed above the ink receiving unit31and below the bottom surfaces7ato10aof the recording heads7to10, and further at an upstream side of the conveyance direction A with respect to the ink receiving unit31(that is, backside). The light emitting element33emits light linearly toward a downstream of the conveyance direction A (that is, frontside) along the conveyance direction A, and the light receiving element34is placed on the line of the emitted light from the light emitting element33. Concretely, the light receiving element34is placed above the ink receiving unit31, below the bottom surfaces7ato10aof the recording heads7to10, and at a downstream side of the conveyance direction A with respect to the ink receiving unit31. The light receiving element34receives light which has passed above the ink receiving unit31from the light emitting element33, and outputs a normal detection signal to a control device60when the light from the light emitting element33is blocked.

As shown inFIG. 2andFIG. 4, the cleaning unit40comprises a base member41which is placed next to the ink receiving unit31to the left, wiper blades42to25for wiping the bottom surfaces7ato10aof each of the recording heads7to10, cap members46to49for sucking (drawing) ink from each of the recording heads7to10, a sucking pump50for generating a sucking force of the cap members46to49, a scraper51for eliminating ink adhering to the wiper blades42to45, a cleaning blade52for sucking ink adhering to the wiper blades42to45, a waste ink tank53for storing ink sucked by the sucking pump50through the cap members46to49, and a driving device55(seeFIG. 5) for moving the base member41vertically and for moving the base member41in front and back directions. Here, a unit comprising the cap members46to49and the sucking pump50is a sucking mechanism for sucking ink from each jet opening of each of the recording heads7to10.

The base member41is moved by the driving device55along the front and back direction inFIG. 2, that is, the conveyance direction A. Further, the base member41is moved by the driving device55along up and down direction. Here, instead of moving the base member41vertically, the recording heads7to10may be provided so as to be moved vertically along with the carriage6.

At the back edge part of the upper surface of the base member41, four wiper blades42to45made of elastomeric material such as silicon rubber or the like are provided so as to stand up. These wiper blades42to45are arranged along the scanning direction B at even intervals that are the same as that of the recording heads7to10. The number of provided wiper blades42to45is the same as that of the provided recording heads7to10. Therefore, each one of the recording heads7to10corresponds to each one of the wiper blades42to45.

On the upper surface of the base member41, the cap members46to49are provided. Each of the cap members46to49is placed at the front of each of the wiper blades42to45. The number of the provided cap members46to49is the same as that of the recording heads42to45. Therefore, each one of the recording heads7to10corresponds to each one of the cap members46to49.

The sucking pump50is provided to each of the four cap members46to49. Here, description will be made in regard to the sucking pump50corresponding to the cap member46. The sucking pump50is placed below the base member41, and the waste ink tank53for storing ink to be dumped is placed below the sucking pump50. Between the base member41and the waste ink tank53, a tube54made of rubber is placed. One edge of the tube54is communicated with the cap member46through the base member41, and another edge of the tube54is communicated with the waste ink tank53. In the middle of the tube54, the sucking pump50that employs a tube system is placed. The sucking pump50generates a sucking force within the cap member46through the tube54by making space within the tube54in a pressure-reduced state. In detail, the sucking pump50comprises a motor90, and a shaft center portion91of the motor90comprises two roller members92and92. A case93of the motor90comprises three projections94,94and94, and the tube54is pinched between the shaft center portion91and each projection94. When the motor90functions to be rotated, the sucking pump50generates a sucking force within the cap member46through the tube54with each roller member92grinding the tube54.

Below the cap member46, an electromagnetic valve56for freeing a sucking force within the cap member46is provided. In a state where a sucking force is generated within the cap member46, when the electromagnetic valve is freed, pressure within the cap member46is increased back to atmosphere pressure.

Here, description has been made in regard to the sucking pump50and the electromagnetic valve56involved with the cap member46, which is one among the four cap members46to49. However, such sucking pump50and electromagnetic valve56correspond to each of the four cap members46to49and are provided with each of the cap members46to49. Further, within each of the cap members46to49, it is possible to suitably change a sucking force in correspondence with an operation condition of the sucking pump50.

Above the base member41, the scraper51is placed. With the wiper blades42to45moved in the front direction so as to follow the base member41, the scraper51scrapes with the surfaces of the wiper blades42to45.

Behind the scraper51, the cleaning blade52is placed. With the wiper blades42to45moved in the back direction so as to follow the base member41, the cleaning blade52is contacted with the wiper blades42to45. When the cleaning blade52is contacted with the wiper blades42to45, ink adhering to the surfaces of the wiper blades42to45is absorbed in the cleaning blade52.

As shown inFIG. 5, the inkjet printer1comprises a conveyance motor11, a carriage motor12, a jetting examination sensor32, and a control device60which controls the sucking pump50and the driving device55.

The control device60comprises a system controller61, a main memory62which provides an operation area of the system controller61, a reception buffer memory63for temporarily storing data in order to transmit/receive image data or the like to/from a host computer80, an image buffer64for temporarily storing the image data received from the host computer80, a timer65for performing measurement according to a clock signal, a main scanning driver66for driving and controlling the carriage motor12, a sub scanning driver67for driving and controlling the conveyance motor11, a sucking driver68for driving and controlling the sucking pump50, a wiping driver69for driving and controlling the driving device55, a valve driver for driving and controlling the electromagnetic valve56, a head driver71for driving the recording heads7to10according to the image data stored in the image buffer64, and an interface72for inputting a detection signal from the jetting examination sensor32.

The control device60controls the carriage motor.12, the conveyance motor11, the sucking pump50, the electromagnetic valve56, and the recording heads7to10through each of the drivers66to71by data-processing at the system controller61by using the main memory62as an operation area. When a normal detection signal is inputted from the jetting examination sensor32(light receiving34) through the interface72, the control device60detects normality of jet openings of the recording heads7to10. On the contrary, when a normal detection signal is not inputted from the jetting examination sensor32(light receiving element34) through the interface72, the control device60detects jetting failure of jet openings of the recording heads7to10. Further, the control device60performs counting according to the data processing of the system controller61. Counted number which is counted by the system controller61is stored in the main memory62. Further, the control device60compares the counted number with predetermined number M, predetermined count I, predetermined count J, predetermined number K1, predetermined count K2and the like. Further, the control device60performs measurement with the timer65.

Further, a start input button is connected to the control device60. When a user pushes the start input button, a cleaning start signal is inputted to the control device60from the start input button.

Next, an operation and effect of the inkjet printer1will be described.

When the control device60receives image data (image recording start signal) from the host computer80, the control device outputs a control signal to the conveyance motor11, the carriage motor12, the recording heads7to10and the like, for controlling operations of each structure in the following way. That is, with the control device60repeating the starting and stopping of the conveyance motor11, each of the conveyance rollers3and4repeats rotation as much as predetermined amount and stoppage thereof, whereby the recording medium99is moved along the conveyance direction A intermittently.

While the movement of the recording medium99is temporarily being stopped in this state, when the control device60actuates the carriage motor12, the carriage6is moved along with each of the recording heads7to10right above the recording medium99from left to right (or from right to left) inFIG. 2along the scanning direction B. Then, while the carriage6is moving, when the control device60makes each of the recording heads7to10perform a jetting operation suitably according to image data, ink is jetted as minute droplet toward the recording surface of the recording medium99from jet openings on the bottom surfaces7ato10aof each of the recording heads7to10.

Thereafter, with each component of the inkjet printer1repeating the above-described operation, images are sequentially recorded on an image recording area of the recording surface of the recording medium passing over the platen2.

Here, in addition to the above-described image recording operation, the inkjet printer1performs a recovering operation which recovers the recording heads7to10from jetting failure. There are nine types of recovering operations of the inkjet printer1. Hereinafter, the nine types of recovering operations will sequentially be described. Here, the jetting failure means that ink is not jetted from a jet opening even though the recording heads7to10performs an ink jetting operation.

A first recovering operation among the nine types of recovering operations will be described with reference toFIG. 6.FIG. 6is a flowchart illustrating a first recovering processing mode by the control device60at the first recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The sucking and wiping operation is performed in the following way.

That is, when the control device60actuates the carriage motor12, the carriage6is moved to above the base member41so as to locate the recording heads7to10above the cap members46to49, respectively. Next, when the control device60actuates the driving device55, the base member41is moved up so as to contact the cap members46to49with the bottom surfaces7ato10aof the recording heads7to10, respectively.

After the cap members46to49respectively get contacted with the bottom surfaces7ato10a,when the control device60actuates the sucking pump50, pressure within the cap members46to49is reduced, whereby ink is sucked from each jet opening of the recording heads7to10. After predetermined period passes in this state, when the control device60stops the sucking pump50and opens the electromagnetic valve56, pressure within the cap members46to49becomes atmosphere pressure.

Next, when the control device60actuates the driving device55, the base member41moved down to the former height, and the base member41moves from back to front. At this time, upper parts of the wiper blades42to45move so as to respectively wipe the bottom surfaces7ato10aof the recording heads7to10, whereby ink adhering to the bottom surfaces7ato10ais eliminated. Thereafter, when the driving device55moves the base member41from front to back, the wiper blades42to45get contacted with the cleaning blade52. Thereby, ink adhering to the wiper blades42to45is absorbed by the cleaning blade52. Here, since the scraper51scrapes the wiper blades42to45before the wiper blades42to45respectively get contacted with the recording heads7to10, ink adhering to the wiper blades42to45is eliminated.

When the sucking and wiping process of Step SA1is completed, the control device60makes the jetting examination sensor32examine whether there is any jet opening causing jetting failure among all the jet openings of the recording heads7to10, for counting the number of jet openings causing jetting failure. Concretely, a process for counting the number of jet openings causing jetting failure is performed in the following way.

That is, when the control device60actuates the carriage motor12, the carriage6is moved so as to locate the recording head7above the ink receiving unit31. When the recording head7is located above the ink receiving unit31, the control device60makes all the jet openings of the recording head7perform the simulated jetting. In this case, the control device60makes a plurality of jet openings forming a line jet ink for the simulated jetting, by one jet opening at a time from one edge to another edge. Further, the similar operation is performed on each line.

If ink is normally jetted from a jet opening, since light emitted from the light emitting element33is temporarily blocked by the ink and received by the light receiving element34, the light receiving element.34outputs a normal detection signal to the control device60. When the light receiving element34of the jetting examination sensor32inputs the detection signal at the time that a jet opening performs the simulated jetting, the control device60detects that the jet opening is able to normally jet ink. On the other hand, when ink is not jetted from a jet opening because of the fact that light emitted from the light emitting element34is directly received by the light receiving element34without being blocked, the light receiving element34does not output a normal detection signal to the control device60. When the light receiving element34does not input the normal detection signal at the time that the jet opening performs the simulated jetting, the control device60detects that the jet opening is not able to jet ink and count-up is performed.

When all the jet openings of the recording head7are examined in regard to jetting failure, the control device60counts the number of jet openings causing jetting failure with respect to each of the recording heads8to10, as well as the case of the recording head7. The control device60stores the counted number of jet openings causing jetting failure in the main memory. Here, the sum total of the number of jet openings causing jetting failure with respect to the recording heads7to10may be stored in the main memory, or the number of jet openings causing jetting failure with respect to each of the recording heads7to10may be stored in the main memory.

Next, the control device60compares the number of jet openings causing jetting failure counted in the Step SA2(sum total of the number of jet openings causing jetting failure with respect to the recording heads7to10) with the predetermined number M. Here, the predetermined number M is more than zero and less than the sum total of the number of all the jet openings of the recording heads7to10. For example, if the number of all the jet openings of the recording heads7to10is 2048, the predetermined number M is set to 20. If the control device60judges the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the process of the control device60returns to Step SA2, and the control device60performs the process of Step SA2again. Therefore, until the number of jet openings causing jetting failure becomes not more than the predetermined number M, the control device60repeats the processes in the order of Step SA2and Step SA3. Since it is possible to reduce the number of jet openings causing jetting failure as the predetermined number M becomes smaller, it is possible to record a better image. Here, if the number of jet openings causing jetting failure with respect to each of the recording heads7to10is stored in the main memory, the number of jet openings causing jetting failure with respect to each of the recording heads7to10may be compared with a predetermined number M′ in Step SA3. In this case, the predetermined number M′ is more than zero and less than the number of jet openings of each of the recording heads7to10. For example, if the number of jet openings of the recording head7is 512, the predetermined number M′ is set to 4.

Here, after the completion of the above-described first recovering operation, when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

As mentioned, in the first recovering operation, after the sucking and wiping process of Step SA1is performed, the examination process of SA2, which counts the number of jet openings causing jetting failure, is performed, wherein, when the number of jet openings causing jetting failure is more than the predetermined number M, what is performed is not the sucking process again but the examination process repeatedly. Therefore, while the examination process is being repeated, the number of jet openings causing jetting failure is reduced. Then, when the number of jet openings causing jetting failure becomes not more than the predetermined number M, the operation of the inkjet printer1is transferred to the image recording operation. Therefore, it is possible to minimize the time to transfer the operation to the image recording operation, and further, it is possible to prevent missing dot in a recording image, whereby it is possible to suppress image deterioration.

A second recovering operation among the nine types of recovering operations will be described with reference toFIG. 7.FIG. 7is a flowchart illustrating a second processing mode performed by the control device60at the second recovering operation, with time.

The control device60examines whether there is any jet opening causing jetting failure among all the jet openings of the recording heads and counts the number of jet openings causing jetting failure, at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SB1is the same as the process in Step SA2of the first recovering processing mode.

Next, the control device60compares the number of jet openings causing jetting failure counted in Step SB1with predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number according to the comparison result, the process of the control device60is transferred to Step SB3.

In Step SB3, the control device60performs the sucking and wiping process of the recording heads7to10. The process of the control device60in Step SB3is the same as the process in Step SA1of the first recovering processing mode.

Following Step SB3, the control device60counts the number of jet openings causing jetting failure among all the jet openings of the recording heads7to10. The process of the control device60in Step SB3is the same as the process in Step SA2of the first recovering processing mode.

Following Step SB4, the control device60compares the number of jet openings causing jetting failure counted in Step SB4with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the process of the control device60returns to Step SB4, and the control device60performs the process of Step SB4again. Therefore, until the number of jet openings causing jetting failure becomes not more than the predetermined number M, the control device60repeats the process of Step SB4.

Here, after the completion of the above-described second recovering operation, when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

As mentioned, also in the second recovering operation, after the sucking and wiping process in Step SB3is performed, the examination process in Step SB4, which counts the number of jet openings causing jetting failure, is performed, wherein, when the number of jet openings causing jetting failure is more than the predetermined number M, what is performed is not the sucking process again, but the examination process repeatedly. Therefore, while the examination process is being repeated, the number of jet openings causing jetting failure is reduced. Then, when the number of jet openings causing jetting failure becomes not more than the predetermined number M, the operation of the inkjet printer1is transferred to the image recording operation. Thereby, it is possible to prevent missing dot in a recording image, whereby it is possible to suppress image deterioration.

Meanwhile, the control device60performs the sucking and wiping process of Step SB1before the sucking and wiping process of Step SB3, and according to the examination result, if the number of jet openings causing jetting failure is not more than the predetermined number M, the control device60does not perform the sucking and wiping process of Step SB3. Therefore, it is possible to prevent jetting failure from being caused by the sucking and wiping process of Step SB3, and further, it is possible to minimize the operation time.

A third recovering operation among the nine types of recovering operations will be described with reference toFIG. 8.FIG. 8is a flowchart illustrating a third recovering processing mode performed by the control device60at the third recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SC1is the same as the process in Step SA1of the first recovering processing mode.

Following Step SC1, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SC2is the same as the process in Step SA2of the first recovering processing mode.

Following Step SC2, the control device60performs a flushing process (simulated jetting process) of the recording heads7to10. Concretely, when the control device60actuates the carriage motor12, the carriage6is moved so as to locate the recording head7above the ink receiving unit31. When the recording head7is located above the ink receiving unit31, the control device60makes all the jet openings of the recording head7perform the simulated jetting. Here, the control device60may make all the jet openings of the recording head7perform the simulated jetting simultaneously, or may make the jet openings of the recording head7perform the simulated jetting in predetermined order. When the simulated jetting of all the jet openings of the recording head7is completed, the control device makes the carriage motor12move so as to locate the recording heads8to10also above the ink receiving unit31sequentially. Then, when the recording heads8to10are respectively located above the ink receiving unit31, the control device60makes all the jet openings of each of the recording heads8to10jet ink to perform the simulated jetting. Since the flushing process in SC3performs the simulated jetting from each jet opening of the recording heads7to10after the sucking and wiping process in Step SC2, it is possible to promote recovering a jet opening from jetting failure to a state to be able to jet ink.

Here, in the flushing process of Step SC3, a position where the recording heads7to10perform the simulated jetting is the same as where the recording heads7to10perform the simulated jetting in the jetting examination process of Step SC2.

Following Step SC3, the control device60compares the number of jet openings causing jetting failure counted in Step SC2with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the process of the control device60returns to Step SC2, and the control device60performs the process of Step SC2again. Therefore, until the number of jet openings causing jetting failure becomes not more than the predetermined number M, the control device60repeats the processes of Step SC2and Step SC3.

Here, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M in the process of Step SC4, the process of the control device60may return to Step SC3, and until the number of jet openings causing jetting failure becomes not more than the predetermined number M, the control device60may repeat the process of SC3.

After the completion of the above-described third recovering operation, when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

A fourth recovering operation among the nine types of recovering operations will be described with reference toFIG. 9.FIG. 9is a flowchart illustrating a fourth recovering processing mode performed by the control device60at the fourth recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SD1is the same as the process in Step SA1of the first recovering processing mode.

Following Step SD1, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SD2is the same as the process in Step SA2of the first recovering processing mode.

Following Step SD2, the control device60compares the number of jet openings causing jetting failure counted in Step SD2with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the control device60counts up the examination count, and the process of the control device60is transferred to Step SD4. Here, after Step SD3, when the process of the control device60is completed and when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

In Step SD4, the control device60compares the examination count which is counted up in Step SD3with predetermined count I. If the control device60judges that the examination count is not more than the predetermined count I according to the comparison result, the process of the control device60returns to Step SD2, and the control device60performs the process of Step SD2again. Therefore, until the examination count exceeds the predetermined count I, the control device60performs the processes of Step SD2and Step SD3. On the other hand, if the examination count exceeds the predetermined count I by repeating Step SD2and Step SD3, the process of the control device60is transferred to Step SD5. Here, while the control device60is repeating the processes of Step SD2and SD3, if the number of jet openings causing jetting failure is not more than the predetermined number M (Step SD3; Yes), the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed.

In Step SD5, the control device60transmits an error signal to the host computer80, and the host computer80performs an error display. Then, the process of the control device60is finished. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

As mentioned, also in the fourth recovering operation, after the sucking and wiping process of Step SD1is performed, the jetting examination process of Step SD2, which counts the number of jet openings causing jetting failure, is performed, wherein the jetting examination process is repeatedly performed when the number of jet openings causing jetting failure is more than the predetermined number M. Therefore, while the jetting examination process is being repeated, the number of jet openings causing jetting failure is reduced. Further, with the error display performed in Step SD5, it is possible to notify a user or the like of the necessity of maintenance of the recording heads7to10.

A fifth recovering operation among the nine types of recovering operations will be described with reference toFIG. 10.FIG. 10is a flowchart illustrating a fifth recovering processing mode performed by the control device60at the fifth recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SE1is the same as the process in Step SA1of the first recovering processing mode. However, in Step SE1, after performing the sucking and wiping process, the control device60counts up the count of performing the sucking and wiping process.

Following Step SE1, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SE2is the same as the process in Step SA2of the first recovering processing mode.

Following Step SE2, the control device60compares the number of jet openings causing jetting failure counted in Step SE2with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the control device60counts up the examination count, and the process of the control device60is transferred to Step SE4. Here, after Step SE3, when the process of the control device60is completed and when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

In Step SE4, the control device60compares the examination count which is counted up in Step SE3with predetermined count I. If the control device60judges that the examination count is not more than the predetermined count I according to the comparison result, the process of the control device60returns to Step SE2, and the control device60performs the process of Step SE2again. Therefore, until the examination count exceeds the predetermined count I, the control device60repeats the processes of Step SE2and Step SE3. On the other hand, if the examination count exceeds the predetermined count I by repeating Step SE2and Step SE3, the process of the control device60is transferred to Step SE5. Here, while the control device60is repeating the processes of Step SE2and SE3, if the number of jet openings causing jetting failure is not more than the predetermined number M (Step SE3; Yes), the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed.

[Step SE5: Sucking and Wiping Process Count Comparing Process]

In Step SE5, the control device60compares the count of the sucking and wiping process counted up in Step SE1with predetermined count J. If the control device60judges that the count of performing the sucking and wiping process is not more than the predetermined count J according to the comparison result, the process of the control device60returns to Step SE1, and the control device60performs the process of Step SE1again. Therefore, until the count of performing the sucking and wiping process exceeds the predetermined count J, the control device60repeats the processes from Step SE1to Step SE4. On the other hand, if the count of performing the sucking and wiping process exceeds the predetermined count J by repeating from Step SE1to Step SE4, the process of the control device60is transferred to Step SE6.

In Step SE6, the control device60transmits an error signal to the host computer80, and the host computer80performs an error display. Then, the process of the control device60is finished. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

As mentioned, also in the fifth recovering operation, after the sucking and wiping process of Step SE1is performed, the jetting examination process of Step SE2, which counts the number of jet openings causing jetting failure, is performed, wherein the jetting examination process is repeatedly performed when the number of jet openings causing jetting failure is more than the predetermined number M. Therefore, while the jetting examination process is being repeated, the number of jet openings causing jetting failure is reduced. Further, with the error display performed in Step SE5, it is possible to notify a user or the like of the necessity of maintenance of the recording heads7to10.

A sixth recovering operation among the nine types of recovering operations will be described with reference toFIG. 11.FIG. 11is a flowchart illustrating a recovering processing mode performed by the control device at the sixth recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SF1is the same as the process in Step SA1of the first recovering processing mode.

Following Step SF1, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SF2is the same as the process in Step SA2of the first recovering processing mode.

Following Step SF2, the control device60compares the number of jet openings causing jetting failure counted in Step SF2with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the control device60counts up the examination count, and the process of the control device60is transferred to Step SF4. Here, after Step SF3, when the process of the control device60is completed and when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

In Step SF4, the control device60compares the examination count which is counted up in Step SF3with predetermined count I. If the control device60judges that the examination count is not more than the predetermined count I according to the comparison result, the process of the control device60returns to Step SF2, and the control device60performs the process of Step SF2again. Therefore, until the examination count exceeds the predetermined count I, the control device60performs the processes of Step SF2and Step SF3. On the other hand, if the examination count exceeds the predetermined count I by repeating Step SF2and Step SF3, the process of the control device60is transferred to Step SF5. Here, while the control device60is repeating the processes of Steps SF2and SF3, if the number of jet openings causing jetting failure is not more than the predetermined number M (Step SF3; Yes), the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed.

[Step SF5: Forcible Sucking and Wiping Process Count Comparing Process]

In Step SF5, the control device60compares a count of performing a forcible-sucking and wiping process, the count being counted up in the later-described Step SF6, with a predetermined number K. If the control device60judges that the count of performing the forcible-sucking and wiping process is not more than the predetermined number K according to the comparison result, the process of the control device60is transferred to Step SF6and to Step SF2, and the control device60performs the process of Step SF2again. Therefore, until the count of performing the forcible-sucking and wiping process exceeds the predetermined number K, the control device60repeats the processes of Step SF2to Step SF6. On the other hand, if the count of performing the forcible-sucking and wiping process exceeds the predetermined number K by repeating from Step SF2to Step SF6, the process of the control device60is transferred to Step SF7.

In Step SF6, the sucking and wiping process is performed as well as the case of Step SF1. However, when the control device60actuates the sucking pump50, a sucking force of the sucking pump50is made higher than the sucking force of the sucking pump50in a former sucking and wiping process. Here, the former sucking and wiping process is, when the process of Step SF6is performed at the first time, the sucking and wiping process of Step SF1, or when the process of Step SF6is performed at the second time or later, the sucking and wiping process of Step SF6. Here, after Step SF6, the process of the control device60returns to Step SF2.

In Step SF7, the control device60transmits an error signal to the host computer80, and the host computer80performs an error display. Then, the process of the control device60is finished. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

As mentioned, also in the sixth recovering operation, after the sucking and wiping process of Step SF1is performed, the jetting examination process of Step SF2, which counts the number of jet openings causing jetting failure, is performed, wherein the jetting examination process is repeatedly performed if the number of jet openings causing jetting failure exceeds the predetermined number. Therefore, while the jetting examination process is repeated, the number of jet openings causing jetting failure is reduced. Further, when the count of performing the jetting examination process of Step SF2exceeds the predetermined count I, since the sucking is performed with a higher forcible-sucking force in Step SF6, it is possible to eliminate jet openings causing jetting failure more surely and quickly. Further, since the sucking process of Step SF1does not involve a high sucking force, it is possible to prevent from wasting ink.

A seventh recovering operation among the nine types of recovering operations will be described with reference toFIG. 12.FIG. 12is a flowchart illustrating a seventh recovering processing mode performed by the control device60at the seventh recovering operation, with time.

The control device60performs a sucking and wiping process of the recording heads7to10at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SG1is the same as the process in Step SA1of the first recovering processing mode. However, in the Step SG1, after performing the sucking and wiping process, the control device60counts up the count of performing the sucking and wiping process.

Following Step SG1, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SG2is the same as the process in Step SA2of the first recovering processing mode.

Following Step SG2, the control device60compares the number of jet openings causing jetting failure counted in Step SG2with the predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the control device60counts up the number of examination count, and the process of the control device60is transferred to Step SG4. Here, after Step SG3, when the process of the control device60is completed and when the host computer80inputs image data to the control device60, the inkjet printer1performs the above-described [1. image recording operation].

In Step SG4, the control device60compares the examination count which is counted up in Step SG3with predetermined count I. If the control device60judges that the examination count is not more than the predetermined count I according to the comparison result, the process of the control device60returns to Step SG2, and the control device60performs the process of Step SG2again. Therefore, until the examination count exceeds the predetermined count I, the control device60repeats the processes of Step SG2and Step SG3. On the other hand, if the examination count exceeds the predetermined count I by repeating Step SG2and Step SG3, the process of the control device60is transferred to Step SG5. Here, while the control device60is repeating the processes of Step SG2and SG3, if the number of jet openings causing jetting failure is not more than the predetermined number M (Step SG3; Yes), the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed.

[Step SG5: Sucking and Wiping Process Count Comparing Process]

In Step SG5, the control device60compares the count of performing the sucking and wiping process counted up in Step SG1with predetermined count J. If the control device60judges that the count of performing the sucking and wiping process is not more than the predetermined count J according to the comparison result, the process of the control device60returns to Step SG1, and the control device60performs the process of Step SG1again. Therefore, until the count of performing the sucking and wiping process exceeds the predetermined count J, the control device60repeats the processes from Step SG1to Step SG4. On the other hand, if the count of performing the sucking and wiping process exceeds the predetermined count J by repeating from Step SG1to Step SG4, the process of the control device60is transferred to Step SG6.

In Step SG6, with the control device60making the jetting examination sensor32examine whether there is any jet opening causing jetting failure among all the jet openings of the recording heads7to10, the number of jet openings causing jetting failure is counted with respect to each of the recording heads7to10, and a recording head whose number of jet openings causing jetting failure is more than predetermined count is identified among the recording heads7to10. Then, the process of the control device60is transferred to Step SG7.

[Step SG7: Error Process Indicating Exchange of Identified Recording Head]

In Step SG7, the control device60transmits an error signal indicating exchange of the recording head identified in Step SG6to the host computer80, and the host computer80performs an error display indicating exchange of the identified recording head. Then, the process of the control device60is finished. Here, the control device60may be connected to a display device to perform the error display indicating exchange of the identified recording head on the display device, or the control device60may be connected to a buzzer to output an error sound indicating exchange of the identified recording head from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error indicating exchange of the identified recording head.

As mentioned, also in the seventh recovering operation, after the sucking and wiping process of Step SG1is performed, the jetting examination process of Step SG2, which counts the number of jet openings causing jetting failure, is performed, wherein the jetting examination process is repeatedly performed when the number of jet openings causing jetting failure exceeds the predetermined number M. Therefore, while the jetting examination process is being repeated, the number of jet openings causing jetting failure is reduced. Further, when the count of performing the jetting examination process exceeds the predetermined count I, a recording head whose number of jet openings causing jetting failure is more than predetermined count Is identified among the recording heads7to10, and a display indicating exchange of the identified recording head is performed. Therefore, it is possible to prompt a user to exchange the head with the display.

An eighth recovering operation among the nine types of recovering operations will be described with reference toFIG. 13.FIG. 13is a flowchart illustrating an eighth recovering processing mode performed by the control device60at the eighth recovering operation, with time.

When the above-described [1. image recording operation] is completed, the control device60makes a timer65start time measurement.

While the timer65is doing the time measurement, the control device60judges whether an image recording start signal is received from the host computer80. Here, if the image recording start signal is inputted to the control device60, the process of the control device60is transferred to Step SH3. On the other hand, if the image recording start signal is not inputted to the control device60, the process of the control device60is transferred to Step SH5.

In Step SH3, the control device60receives image data from the host computer80and the inkjet printer1performs the above-described [1. image recording operation]. Thereafter, the process of the control device60is transferred to Step SH4. Here, when the process is transferred from Step SH2to Step SH3, the control device60may perform a process which is identical to the process of Step SA2in the first recovering processing mode after Step SH2and before SH3.

In Step SH4, the control device60resets the time measurement of the timer65. Thereafter, the process of the control device60returns to Step SH1, and as described above, the control device60makes the timer65start the time measurement in Step SH1.

In Step SH5, the control device60judges whether predetermined time T has passed since the time measurement start in Step SH1. Then, if the predetermined time T has not passed since the time measurement start, the process of the control device60returns to Step SH2. Then, if the predetermined time T has passed since the time measurement start, the process of the control device60is transferred to Step SH6.

In Step SH6, the control device60performs the sucking and wiping process of the recording heads7to10. The process of the control device60in Step SH6is the same as the process of the Step SA1in the first recovering processing mode. However, in Step SH6, after performing the sucking and wiping process, the control device60counted up the count of performing the sucking and wiping process.

Following Step SH6, the control device60counts the number of jet openings causing jetting failure of the recording heads7to10. The process of the control device60in Step SH7is the same as the process of Step SA1in the first recovering processing mode.

Following Step SH6, the control device60compares the counted number of jet openings causing jetting failure with predetermined number M. If the control device60judges that the number of jet openings causing jetting failure is not more than the predetermined number M according to the comparison result, the process of the control device60is transferred to Step SH12. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is more than the predetermined number M according to the comparison result, the control device60counts up the examination count and the process of the control device60is transferred to Step SH9.

In Step SH9, the control device60compares the examination count which is counted up in Step SH8with predetermined count I. If the control device60judges that the examination count is not more than the predetermined count I according to the comparison result, the process of the control device60returns to Step SH7, and the control device60performs the process of Step SH7again. Therefore, until the examination count exceeds the predetermined count I, the control device60repeats the processes of Step SH7and Step SH8. On the other hand, if the examination count exceeds the predetermined count I by repeating Step SH7and Step SH8, the process of the control device60is transferred to Step SH10. Here, while the control device60is repeating the processes of Step SH7and SH8, if the number of jet openings causing jetting failure is not more than the predetermined number M (Step SH8; Yes), the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed.

[Step SH10: Sucking and Wiping Process Count Comparing Process]

In Step SH10, the control device60compares the count of performing the sucking and wiping process counted up in Step SH6with predetermined count J. If the control device60judges that the count of performing the sucking and wiping process is not more than the predetermined count J according to the comparison result, the process of the control device60returns to Step SH6, and the control device60performs the process of Step SH6again. Therefore, until the count of performing the sucking and wiping process exceeds the predetermined count J, the control device60repeats the processes from Step SH6to Step SH10. On the other hand, if the count of performing the sucking and wiping process exceeds the predetermined count J by repeating from Step SH6to Step SH10, the process of the control device60is transferred to Step SH11.

In Step SH11, the control device60transmits an error signal to the host computer80, and the host computer80performs an error display. Then, the process of the control device60is finished. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

In Step SH12, the control device60resets the time measurement of the timer65. Thereafter, the process of the control device60returns to Step SH1, and as described above, the control device60makes the timer65start the time measurement in Step SH1.

As mentioned, also in the eighth recovering operation, after the sucking and wiping process of Step SH6is performed, the jetting examination process of Step SH7, which counts the number of jet openings causing jetting failure, is performed, wherein the jetting examination process is repeatedly performed when the number of jet openings causing jetting failure is more than the predetermined number M. Therefore, while the jetting examination process is being repeated, the number of jet openings causing jetting failure is reduced. Further, although there is a possibility of causing jetting failure due to viscosity increase of ink existing at each jet opening of the recording heads7to10after the image recording process of Step SH3, since the sucking and wiping process of Step SH6is performed after predetermined time has passed since the image recording process, it is possible to suppress jetting failure at a jet opening due to viscosity increase.

A ninth recovering operation among the nine types of recovering operations will be described with reference toFIGS. 14A and 14B.FIGS. 14A and 14Bare a flowchart illustrating a ninth recovering processing mode performed by the control device60at the ninth recovering operation, with time.

Here, in the ninth recovering operation, a recovering transition will be described only with respect to one recording head, which is the recording head7.

The control device60examines whether there is any jet opening causing jetting failure among all the jet openings of the recording head7and counts the number of jet openings causing jetting failure, at the time of: turning on the power of the inkjet printer1; pushing the start input button by a user; inputting an image recording start signal to the control device60from the host computer80(before the above-mentioned [1. image recording operation]), or the like. The process of the control device60in Step SJ1is the same as the process in Step SA2of the first recovering processing mode.

When the jetting examination process of Step SJ1is completed, the control device60judges whether the number of jet openings causing jetting failure counted up in Step SJ1is not less than predetermined number K1. If the control device60judges that the number of jet openings causing jetting failure is less than the predetermined number K1according to the judgment result (Step SJ2; NO), it is determined that a recovering operation from jetting failure is not necessary except for the simulated jetting, and the control device60makes all the jet openings of the recording head7jet ink for performing the simulated jetting again. Then, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is not less than the predetermined number K1according to the judgment result (Step SJ2; YES), the process of the control device60is transferred to Step SJ3.

In Step SJ3, due to the fact that it is determined that a recovering operation from jetting failure is necessary in addition to the simulated jetting, the control device60stores jetting failure information regarding a jet opening causing jetting failure (information regarding the total number, locations and the like of jet openings causing jetting failure, hereafter, it is referred to as “first jetting failure information”) in the main memory62as data, based on a detection result by the jetting examination sensor32.

Following Step SJ3, the control device60performs the sucking and wiping process of the recording head7. The process of the control device60in Step SJ4is the same as the process of Step SA1in the first recovering processing mode. In Step SJ4, after performing the sucking and wiping process, the control device60counts up the count of performing the sucking and wiping process.

Here, in the sucking and wiping process in Step SJ4, ink sucking time from each jet opening of the recording head7(operation time of the sucking pump50) is, for example, set to 5 seconds.

Following Step SJ4, the control device60counts the number of jet openings causing jetting failure among all the jet openings of the recording head7. The process of the control device60in Step SJ5is the same as the process of Step SA2in the first recovering processing mode.

Following Step SJ5, the control device60judges whether the number of jet openings causing jetting failure counted up in Step SJ5is not less than the predetermined number K1. If the control device60judges that the number of jet openings causing jetting failure is less than the predetermined number K1according to the judgment result (Step SJ6; NO), it is determined that a recovering operation from jetting failure is not necessary except for the simulated jetting, and the control device60makes all the jet openings of the recording head7jet ink for performing the simulated jetting again. Then, the process of the control device60is finished, and the recovering operation of the inkjet printer1is completed. On the other hand, if the control device60judges that the number of jet openings causing jetting failure is not less than the predetermined number K1according to the judgment result (Step SJ6; YES), the process of the control device60is transferred to Step SJ7.

In Step SJ7, due to the fact that it is determined that a recovering operation from jetting failure is necessary in addition to the simulated jetting, the control device60stores jetting failure information regarding a jet opening causing jetting failure (information regarding the total number, locations and the like of jet openings causing jetting failure, hereafter, it is referred to as “second jetting failure information”) in the main memory62as data, based on a detection result by the jetting examination sensor32.

Here, the predetermined number K1, which is used for the judgment in the processes of Step SJ2and Step SJ6, can be suitably set according to image quality in connection with the described [1. image recording operation]. For example, it can be set to one-tenth of the number of all the jet openings, or can be set to 1, extremely speaking. In other words, if the predetermined number K1is set to one-tenth of the number of all the jet openings, when it is judged that the number of jet openings causing jetting failure is not less than one-tenth of the number of all the jet openings, the first jetting failure information storing process and the second jetting failure information storing process are performed. Further, if the predetermined number K1is set to 1, if it is judged that there is at least one jet opening causing jetting failure, the first jetting failure information storing process and the second jetting failure information storing process are performed. By making the predetermined number K1smaller, more accurate detection of jetting failure can be obtained, whereby it is possible to improve image quality in connection with the described [1. image recording operation].

Following Step SJ7, in consideration with the first jetting failure information and the second jetting failure information, the control device60judges whether the total number of jet openings causing jetting failure is continuously not less than the predetermined number K1(for example, one-third of the number of all the jet openings of the recording head7) through the ink simulated jetting operations based on each of the processes of Step SJ1and Step SJ5. If the control device60judges that the total number of jet openings causing jetting failure is continuously not less than the predetermined number K1according to the judgment result (Step SJ8; YES), the process of the control device60is transferred to Step SJ9. On the other hand, if the control device60judges that the total number of jet openings causing jetting failure does not continuously reach the predetermined number K1(Step SJ8; NO), the process of the control device60is transferred to Step SJ10.

In Step SJ9, the control device60transmits an error signal indicating that the recording head7is out of ink to the host computer80, and the host computer80performs an error display indicating that the recording head7is out of ink. Since it is judged that the number of jet openings causing jetting failure is continuously not less than the predetermined number K1through the two times of ink simulated jetting operations, which are respectively the processes of Step SJ1and Step SJ5, it is judged that “out of ink” happens in the recording head and a user is notified accordingly from the error display. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

In Step SJ10, the control device60judges whether the count of performing the sucking and wiping process counted up in Step SJ4, SJ12and SJ13(count of performing the sucking and wiping process to the recording head7) reaches a predetermined count K2(not less than two times). If the control device60judges that the count of performing the sucking and wiping process to the recording head7reaches the predetermined count K2according to the judgment result (Step SJ10; YES), the process of the control device60is transferred to Step SJ14. On the other hand, if the control device60judges that the count of performing the sucking and wiping process to the recording head7does not reach the predetermined count K2(Step SJ10; NO), the process of the control device60is transferred to Step SJ11.

In Step SJ14, the control device60transmits an error signal indicating malfunctioning at the recording head7to the host computer80, and the host computer80performs an error display indicating the malfunctioning at the recording head7. In the processes of Step SJ10and Step SJ14, since it is judged that the count of performing the sucking and wiping process in connection with jetting failure of the recording head reaches the predetermined count K2, it is judged that the jetting failure of jet openings is not recovered despite performing the sucking and wiping process to the recording head7not less than two times, that is, it is judged that “malfunctioning is occurring at the recording head7”, and a user is notified accordingly from the error display. Here, the control device60may be connected to a display device to perform the error display on the display device, or the control device60may be connected to a buzzer to output an error sound from the buzzer, or the control device60may be connected to a light so that the control device60makes the light illuminate or blink to show the error.

In Step SJ11, in consideration with the first jetting failure information and the second jetting failure information, the control device60judges whether there is any common positioned jet opening among jet openings which are judged to be causing jetting failure according to the two times of ink simulated jetting operations based on each of the processes of Step SJ2and SJ6.

Here, it is assumed that the sucking pump50is a pump having a pump characteristic ofFIG. 15.FIG. 15shows a relation between elapsed time [sec] since the start of sucking by the sucking pump50and a sucking force [kPa] of the sucking pump50. As shown inFIG. 15, with the sucking pump50, it is possible to change a sucking force of ink according to the length of sucking time. With reference to the pump characteristic ofFIG. 15, the sucking force reaches 30 kPa at five seconds after the sucking start. Accordingly, as mentioned, if the sucking time is set to five seconds in the process of Step SJ4, a sucking force is set to 30 kPa in the process of Step SJ4.

If the control device60judges that there is no common-positioned jet opening according to the judgment result (Step SJ11; NO), the process of control device60is transferred to Step SJ12. On the other hand, if the control device60judges that there is at least one common-positioned jet opening according to the judgment result (Step SJ11; YES), the process of the control device60is transferred to Step SJ13.

In Step SJ12, the control device60performs the sucking and wiping process to the recording head7so as to make a sucking force of ink equal to or lower than the sucking force at the time of performing former sucking and wiping process, that is, the control device60performs the sucking and wiping process to the recording head7so as to make ink sucking time (operating time of the sucking pump50) equal to or shorter than 5 seconds. The process of the control device60in Step SJ12is the same as the process in Step SA1of the first recovering processing mode except that a sucking force thereof is made equal to or lower than that of a former sucking and wiping process. However, in Step SJ12, after performing the sucking and wiping process, the control device60counts up the count of performing the sucking and wiping process.

The reason why a sucking force of ink in Step SJ12is made equal to or lower than that of a former sucking and wiping process (here, the process of Step SJ4) is, it is considered that air bubble is generated at a jet opening, and therefore, it is considered that it is possible to recover the jet opening from jetting failure by making a sucking force corresponding to sucking time equal to or lower than that of a former sucking and wiping process.

In Step SJ13, the control device60performs the sucking and wiping process to the recording head7so as to make a sucking force of ink higher than that of a former sucking and wiping process, that is, the control device60performs the sucking and wiping process to the recording head7so as to make ink sucking time (operating time of the sucking pump50) longer than 5 seconds. The process of the control device60in Step SJ13is the same as the process in Step SA1of the first recovering processing mode except that a sucking force thereof is made higher than that of the former sucking and wiping process. However, in Step SJ13, after performing the sucking and wiping process, the control device60counts up the count of performing the sucking and wiping process.

The reason why a sucking force of ink is made higher than that of a former sucking and wiping process (here, the process of Step SJ4) is, it is considered that foreign material is clogging at the common jet opening, and therefore, it is considered that it is not possible to recover the jet opening from jetting failure (clogging of foreign material) unless a sucking force corresponding to sucking time is made higher than that of a former sucking and wiping process.

In the process of Step SJ13, for example, if ink sucking time is set to 15 seconds, it is possible to suck ink with the sucking force (60 kPa) which is twice as much as the sucking force in the process of Step SJ4(30 kPa).

When finishing the process of either Step SJ12or Step SJ13, the control device60repeats the processes from Step SJ5to Step SJ12or the processes from Step SJ5to Step SJ13. In this case, when the processes of SJ8, SJ10and SH11are to be performed again, the control device60makes the judgment by comparing jetting failure information stored in the process of former Step SJ7(second jetting failure information) and jetting failure information stored in the process of current Step SJ7(hereafter, it is referred to as “third jetting failure information”).

Further, when the processes of Step SJ12and Step SJ13are to be performed again, the control device60makes the judgment by comparing with a sucking force in former Steps SJ12and SJ13.

For example, as well as the above-described case, it is assumed that the sucking pump50is a pump having the pump characteristic ofFIG. 15. If ink sucking time in the process of Step SJ13at the first time is set to 15 seconds, a sucking force reaches 60 kPa at 15 seconds after the sucking start. Accordingly, if the control device60judges that there is no common-positioned jet opening in the process of Step SJ11at the second time, the control device60performs the same process as Step SA1in which a sucking force of ink is made equal to or lower than the sucking force of the former sucking and wiping process, that is, the same process as Step SA1in which ink sucking time is made equal to or shorter than 15 seconds.

On the other hand, if the control device60judges that there is at least one common-positioned jet opening in the process of SJ11at the second time, the control device60performs the same process as Step SA1in which a sucking force of ink is made higher than the former sucking and wiping process, that is, the same process as Step SA1in which ink sucking time is made longer than 15 seconds.

In the process of Step SJ13at the second time, for example, if ink sucking time is set to 50 seconds, it is possible to suck ink with a sucking force (90 kPa) which is 1.5 times higher than the sucking force in the process of Step SJ13at the first time (60 kPa).

Then, with respect to the process of Step SJ10thereafter, for example, if the predetermined count K2for performing the sucking and wiping process is set to “three times”, since the count of performing the sucking and wiping process to the recording head7at the time of performing the processes of Step SJ12and Step SJ13at the first time is two times, which are the process of Step SJ4and the process of either Step SJ12or Step SJ13at the first time, in this case, the control device60does not perform the process of Step SJ14. However, since the process of either Step SJ12or Step SJ13is performed at the second time, the count of performing the sucking and wiping process to the recording head7is three times. Therefore, at this time, it is judged that malfunctioning is happening to the recording head, and the process of Step SJ14is performed.

Here, in the above, described is the detail of the recovering operation only with respect to one recording head, which is the recording head7. However, the control device60makes each of the recording heads7to10perform the same recovering operation simultaneously. In this case, if there are jet openings causing jetting failure more than the predetermined number K1in at least one of the recording heads7to10, the above-described ninth recovering operation is performed only with respect to the recording head having the jet openings causing jetting failure, among the recording heads7to10. With respect to the other recording heads among the recording heads7to10, the above-described ninth recovering operation is not performed. At this time, if there are jet openings causing jetting failure more than the predetermined number K1in at least two of the four recording heads7to10, sucking time (sucking force) of each of sucking pumps50that corresponds to the recording heads having the jet openings causing jetting failure among the recording heads7to10may be changed independently. Further, if the control device60makes the plurality of recording heads7to10perform the ink sucking operation simultaneously, the sucking operation of the recording heads7to10is performed according to sucking time of a recording head having the highest sucking force, and when the ink sucking operation to the recording heads7to10is completed, the control device60makes the wiper blades42to45eliminate the ink.

As mentioned, in the ninth recovering operation, based on the continuous two pieces of jetting failure information, that are, the first and second jetting failure information, the second and third jetting failure information and the like, if there is no common-positioned jet opening among jet openings causing jetting failure, it is judged that the cause of jetting failure is generation of air bubble. Then, a sucking operation is later performed with a sucking force which is equal to or lower than that of the former sucking operation, whereby, it is possible to suppress the amount of ink to be dumped. On the other hand, if there is a common-positioned jet opening among jet openings causing jetting failure, it is judged that the cause of jetting failure is clogging of foreign material. Then, a sucking operation is later performed with a sucking force which is higher than that of the former sucking operation, whereby, it is possible to more surely eliminate foreign material. Accordingly, it is possible to recover a jet opening causing jetting failure in accordance with a cause of the jetting failure.

Further, in the ninth recovering operation, in addition to recovering a jet openings causing jetting failure, based on continuous two pieces of jetting failure information, that are, the first and second jetting failure information, the second and third jetting failure information and the like, whether the sum total number of jet openings causing jetting failure is continuously not less than the predetermined number K1is judged, and then an error display indicating the recording heads7to10are out of ink is performed. Thereby, it is possible to notify a user that the recording heads7to10are out of ink. Further, in the ninth recovering operation, whether the count of performing the sucking and wiping operation is not less than the predetermined count K2is judged, and an error display indicating that malfunctioning is occurring to the recording heads7to10. Thereby, it is possible to notify a user of the malfunctioning at the recording heads7to10.

Further, in the above ninth recovering operation, described is the case that increase and decrease of a sucking force is suitably changed in accordance with sucking time of the sucking pump50. However, increase and decrease if a sucking force may be suitably changed in accordance with grinding speed of each roller member92of the sucking pump50(rotation speed of the motor90).

The entire disclosure of a Japanese Patent Application No. Tokugan 2004-051753 filed on Feb. 26, 2004, and a Japanese Patent Application No. Tokugan 2004-011686 filed on Jan. 20, 2004, including specifications, claims, drawings and summaries are incorporated herein by reference in their entirety.