Patent Publication Number: US-8123331-B2

Title: Image forming apparatus and information recording medium

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2007-252871, filed on Sep. 28, 2007, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming apparatus which performs an image formation by jetting liquid droplets on to a medium (recording medium), and an information recording medium in which, a computer program which controls the image forming apparatus is recorded. 
     2. Description of the Related Art 
     Generally, an image forming apparatus such as an ink-jet printer, has a timer which measures time, and performs a jetting function recovery operation of recovering a jetting function by preventing thickening of ink at a fixed (constant) time interval. In such image forming apparatus, for example, when charging of an internal battery has stopped with a power supply in OFF state, or when the power supply is switched OFF without the internal battery available inside, it is not possible to realize a time elapsed after the previous jetting function recovery operation when the power supply is switched ON again, and it is not possible to carry out the jetting function recovery operation at a predetermined time interval. 
     Therefore, in many hitherto known image forming apparatuses, when the power supply is switched ON, the jetting function recovery operation is carried out forcibly prior to the image formation (for example, refer to Japanese Examined Patent Application Publication No. H7-57551). 
     SUMMARY OF THE INVENTION 
     In this manner, in an apparatus described (disclosed) in Japanese Examined Patent Application Publication No. H7-57551, the jetting function recovery operation is carried out unconditionally whenever the power supply is switched ON. In other words, irrespective of the fact that not much time has elapsed after the previous jetting function recovery operation, the jetting function recovery operation may be carried out. Therefore, when the power supply is switched ON and OFF frequently during the usage, waiting time for the jetting function recovery operation has been forced (the user is forced to wait for a predetermined time for the subsequent jetting function recovery operation), and there has been a problem of the ink being consumed wastefully. 
     Therefore, an object of the present invention is to provide an image forming apparatus in which, a frequency of carrying out unnecessary jetting function recovery operation is reduced, and an image recording medium in which, a computer program for realizing such image forming apparatus is recorded. 
     According to a first aspect of the present invention, there is provided an image forming apparatus which is connected to a predetermined display and a predetermined input device, and which performs formation of an image by jetting liquid droplets onto a medium, the image forming apparatus including: 
     a liquid droplet jetting head which jets the liquid droplets; 
     a recovery mechanism which recovers a liquid droplet-jetting function, of the liquid droplet jetting head, of jetting the liquid droplets; 
     an information retention mechanism which retains (stores) predetermined history information; and 
     a control mechanism which controls the recovery mechanism based on the history information retained in the information retention mechanism, and which is connected to the display and the input device; 
     wherein when a power supply of the image forming apparatus is switched ON and when there is an abnormality (oddity) in the history information, the control mechanism outputs to the display a signal which causes a predetermined message to be displayed on the display. 
     In the image forming apparatus of the present invention, the information retention mechanism may have a timer which measures a time, and the abnormality in the history information may be a state that the timer is not capable of measuring the time, and the predetermined message may be a message asking a user whether or not an operation for recovering the jetting function by the recovery mechanism is to be performed. 
     According to the image forming apparatus of the present invention, for example, when there is an abnormality in the information retained by the information retention mechanism, as in a case that the timer (time measuring mechanism) as the information retention mechanism is incapable of measuring the time, the control mechanism causes a predetermined message such as a message asking whether or not to carry out the operation for recovering the jetting function (jetting function recovery operation), to be displayed on the display. Accordingly, the user is capable of selecting as to whether or not to perform the jetting function recovery operation at his or her own will. For example, when the user does not think it is necessary to perform the recovery operation as in a case that the time which could not be measured by the timer is short (is a short time), it is possible to make an arrangement not to perform the jetting function recovery operation. Accordingly, it is possible to solve problems such as a waiting time required for the jetting function recovery operation, and any unnecessary consumption of the liquid for image formation. 
     In the image forming apparatus of the present invention, when a signal requesting the operation for recovering the jetting function is inputted from the input device, the control mechanism may make the recovery mechanism recover the jetting function. In this manner, for performing the jetting function recovery operation when requested by the user, it is possible to omit any unnecessary jetting function recovery operation, and it is possible to solve problems such as the waiting time for the jetting function recovery operation, and any unnecessary consumption of a liquid for the image formation. 
     In the image forming apparatus of the present invention, the information retention mechanism may have a timer which measures a time, and the abnormality in the history information may be a state that the timer is not capable of measuring the time, and the predetermined message may be a message asking the user about a duration of time during which the power supply had been switched OFF. 
     In this case, when the time cannot be measured by the timer, the control mechanism displays a message asking the user about the duration of time period during which the power supply had been switched OFF. Accordingly, based on rough or approximate time during which the power supply had been switched OFF, it is possible to optimally control the jetting function recovery operation of the recovery mechanism, and it is possible to solve the problems such as the waiting time for the jetting function recovery operation and the unnecessary consumption of the liquid for the image formation. 
     In the image forming apparatus of the present invention, the control mechanism may make a judgment of whether or not the operation for recovering the jetting function by the recovery mechanism is to be performed, based on an extent, of the duration of time, inputted from the input device. In this manner, by not carrying out the jetting function recovery operation when the duration of time period during which the power supply had been switched OFF is short, it is possible to omit the unnecessary jetting function recovery operation, and it is possible to solve the problems such as the waiting time for the jetting function recovery operation and the unnecessary consumption of the liquid for the image formation. 
     In the image forming apparatus of the present invention, the control mechanism may change an intensity of the jetting function recovery operation by the recovery mechanism, based on the duration of period inputted from the input device. In this case, by changing the intensity (strength) of the jetting function recovery operation based on or depending on to the length of the period during which the power supply had been switched OFF, it is possible to optimally perform the jetting function recovery operation. 
     The image forming apparatus of the present invention may further include a display section as the display and an input section as the input device. Moreover, the information retention mechanism may have a counter which retains (stores) information about a number of the liquid droplets jetted from the liquid droplet jetting head, and the information retention mechanism may have a counter which retains information of a number of the medium on which the image is formed by the liquid droplet jetting head. 
     According to a second aspect of the present invention, there is provided an information recording medium which is readable by a computer and which includes a computer program recorded on the information recording medium, the computer program causes the computer to: 
     make a judgment with respect to an image forming apparatus connected to a predetermined display and a predetermined input device, performing formation of an image by jetting liquid droplets onto a medium, and including a liquid droplet jetting head which jets the liquid droplets, a recovery mechanism which recovers a liquid droplet-jetting function, of the liquid droplet jetting head, of jetting the liquid droplets, and an information retention mechanism which retains predetermined history information; the judgment being about whether or not there is an abnormality in the history information retained by the information retention mechanism when a power supply of the image forming apparatus is switched ON, 
     cause a predetermined message to be displayed on the display when a judgment that there is an abnormality in the history information; and 
     causes the recovery mechanism to recover the liquid droplet-jetting function of the liquid droplet jetting head according to a response, to the message, inputted from the input device. 
     According to the second aspect of the present invention, when there is an abnormality in the information retained by the information retention mechanism, the computer displays on the display a predetermined message such as a message of as to whether or not the jetting function recovery operation is to be performed. Accordingly, the user can select at his or her own will whether or not the jetting function recovery operation is to be carried out. For example, when the user does not think it is necessary to carry out the recovery operation as in a case that the time which could not be measured by the timer is short (is a short time), it is possible to make an arrangement not to carry out the jetting function recovery operation. Accordingly, it is possible to solve problems such as the waiting time for the jetting function recover operation, and the unnecessary consumption of the liquid for image formation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural view of an ink-jet printer according to the present invention; 
         FIG. 2A  is a plan view of an operation panel portion of the ink-jet printer in  FIG. 1 , and  FIG. 2B  and  FIG. 2C  are diagrams describing a display function in a display section in the operation panel portion; 
         FIG. 3  is a plan view of an ink-jet head; 
         FIG. 4A  is a vertical cross-sectional view of a sub-tank portion and the ink-jet head in  FIG. 1 , and  FIG. 4B  shows a cross-sectional view taken along a VIB-VIB line in  FIG. 4A  and a cross-sectional view of a corresponding cap portion; 
         FIG. 5  is a block diagram showing schematically a controller; 
         FIGS. 6A and 6B  are flowcharts describing a cleaning operation of a first embodiment; and 
         FIGS. 7A and 7B  are flowcharts describing a cleaning operation of a second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     An ink-jet printer as a first embodiment of an image forming apparatus of the present invention will be described below while referring to the accompanying diagrams. 
       FIG. 1  is a schematic structural view of an ink-jet printer according to the first embodiment. As shown in FIG.  1 , the ink-jet printer  1  includes mainly a scanning unit which scans by reciprocating a liquid droplet jetting head (ink-jet head)  4 , parallel to a paper P which is an image forming medium, a transporting unit which transports a paper P in a direction orthogonal to a scanning direction, and an ink supply unit which supplies to the ink-jet head  4  a liquid (ink) for image formation, and a recovery unit which makes recover a jetting function of the ink-jet head  4 . In addition to this, the ink-jet printer  1  includes a controller  60  which controls operations of the abovementioned components, and a power supply unit  80  which supplies an electric power for these operations. Moreover, as shown in  FIG. 2 , the ink-jet printer  1  includes an input section  91  (input mechanism) such as a key switch, on an operation panel section  90 , and a display section  92  (display mechanism) such as a liquid crystal display (board). 
     The main scanning unit includes a carriage  2  on which, the ink-jet head  4  is mounted (installed), and makes the carriage  2  reciprocate in the scanning direction (left-right direction in  FIG. 1 ) along a guide shaft  3 . The ink-jet head  4  holds the carriage  2  such that nozzles  25  formed in a lower surface of the carriage  2  are exposed downward (refer to  FIG. 2 ), and jets an ink from the nozzles  25  toward the paper P while reciprocating in the scanning direction along with the carriage  2 . 
     The ink supply unit has four cartridges  14   a ,  14   b ,  14   c , and  14   d  ( 14   a  to  14   d ) installed at a predetermined mounting site (cartridge mounting portion)  13  in ink-jet printer  1  independent of the carriage  2 , four ink tanks  5   a ,  5   b ,  5   c , and  5   d  ( 5   a  to  5   d ) mounted on the carriage  2 , four tubes  6   a ,  6   b ,  6   c , and  6   d  which connect the ink cartridges  14   a  to  14   d  and the ink tanks  5   a  to  5   d  respectively. Inks of black, yellow, cyan, and magenta colors are filled in the ink cartridges  14   a  to  14   d  respectively. These inks of four colors are supplied from the ink cartridges  14   a  to  14   d  to the four ink tanks  5   a  to  5   d , via four tubes  6   a  to  6   d , and are further supplied from the ink tanks  5   a  to  5   d  to the ink-jet head  4 . 
     The transporting unit includes transporting rollers  9  which transport the paper P in the direction orthogonal to the scanning direction of the carriage  2 , at a lower position (downward position) of nozzles  25  of the ink-jet head  4 . 
     The recovery unit performs a purge operation, an air discharge operation, and a flushing operation which have hitherto been known. For the air discharge operation, the ink tanks  5   a  to  5   d  are provided with aid discharge channels  7   a ,  7   b ,  7   c , and  7   d  ( 7   a  to  7   d ) respectively, as shown in  FIG. 4 . The air discharge channels  7   a  to  7   d  are extended in a right direction from an upper surface thereof, and are bent downward in a right end portion thereof, at a substantially right angle. A lower end opening  7   e  of the four air discharge channel  7   a  to  7   d , opens to an outside, at a side of the ink-jet head  4 , and each has a valve  17  provided at an interior. The valves  17  close the air discharge channels  7   a  to  7   d  with respect to the outside all the time, by an action of a spring  18 . 
     An air discharge cap  8  and a purge cap  10  are provided on a side of a transporting area (area of transporting) on which the paper P is transported in the ink-jet printer  1 . The air discharge cap  8  and the purge cap  10  are movable in a vertical direction by an ascending and descending mechanism  19 . When the purge cap  10  moves upward toward the carriage  2  which has moved to a side of the area of transporting of the paper P, the air discharge cap  8  comes in a close contact with the lower end opening  7   e  of the air discharge channels  7   a  to  7   d , and the purge cap  10  makes a close contact with a lower surface of the ink-jet head  4 . A protrusion  8   a  is formed at an interior of the air discharge cap  8 . When the air discharge cap  8  is connected to the lower end opening  7   e  of the air discharge channels  7   a  to  7   d , the protrusion  8   a  pushes up and opens the valve  17 , and an upper (portion) space in a sub tank  5  and an inside of the air discharge cap  8  are connected. 
     The purge cap  10  and the air discharge cap  8  may be moved vertically by a separate ascending and descending mechanism for each. Moreover, the air discharge cap  8  and the protrusion  8   a  therein may be moved vertically by a separate ascending and descending mechanism for each. Furthermore, an arrangement may be made such that the valve  17  inside each of the air discharge channels  7   a  to  7   d  is opened and closed separately. 
     Each of the air discharge cap  8  and the purge cap  10  are connected to a suction pump  12  via a switching unit  11 . The switching unit  11  switches connection and cutting off of the air discharge cap  8 , the purge cap  10 , and the suction pump  12 . 
     When the air discharge cap  8  is connected to the air discharge channels  7   a  to  7   d , and the air discharge cap  8  and the suction pump  12  are connected by the switching unit  11 , the suction pump  12  is operated. At this time, air in an upper portion inside the ink tanks  5   a  to  5   d  is discharged to the outside from the air discharge channels  7   a  to  7   d.    
     Moreover, the lower surface of the ink-jet head  4 , in other words the nozzles  25 , is covered by the purge cap  10 , and the purge cap  10  and the suction pump  12  are connected by the switching unit  11 . At this time (In this state), when the suction pump  12  is operated, the ink in the ink-jet head  4  is sucked from the nozzles  25  (suction purge operation). 
     In the flushing operation, when the carriage  2  has moved to a position at a side of the area of transporting of the recording paper P, by driving the ink-jet head  4  irrespective of the image data, the ink from all the nozzles  25  is jetted to the purge cap  10  or a hitherto known receptacle which is not shown in the diagram. Such flushing operation is carried out for recovering the jetting function of the ink-jet head  4  as it has hitherto been known. 
       FIG. 3  is a diagram showing an example of the ink-jet head  4 . Similarly as a known ink-jet head, the lower surface of the ink-jet head  4  includes a multiple number of (a plurality of) nozzles  25  facing the recording paper and forming a row for an ink of each of black, yellow, cyan, and magenta colors. The nozzles  25  of each row communicate with a manifold channel  21  provided for each ink (for ink of each color), via a pressure chamber  20 . At one end of the manifold channel  21  a supply port  27  which communicates with the sub tank  5  is formed, and the ink which is supplied from the sub tank  5  to the manifold channel  21  is distributed to the pressure chamber  20 . When jetting energy is imparted to the ink in the pressure chamber  20 , the ink becomes (the ink is converted to) ink droplets and is jetted toward the recording paper from the nozzles  25 . As a mechanism for imparting the jetting energy to the ink, it is possible to use a mechanism which uses a deformation of a piezoelectric element, and a mechanism which causes bubbling of ink by a heater. 
     Next, the controller  60  (control mechanism) which controls an operation of the ink-jet printer  1  will be described below while referring to  FIG. 5 . The controller  60  includes components such as a Central Processing Unit (CPU), a Read Only Memory (ROM), and a Random Access Memory (RAM). As shown in  FIG. 5 , the controller  60  operates (functions) an image forming control section  61 , a recovery operation control section  63 , a display control section  66 , and a time measuring section  68  (time measuring mechanism, timer) as shown in  FIG. 5 . 
     At the time of carrying out image formation based on image data input from an external equipment such as a personal computer (PC)  90  and a facsimile, the image forming control section  61  controls an operation of the ink-jet head  4 , the main scanning unit, and the transporting unit. 
     The recovery operation control section  63  is a section which controls a cleaning operation (jetting function recovery operation) of recovering the jetting function of the ink-jet head  4 , such as, the purge operation, the air discharge operation, and the flushing operation, and includes a flushing control section  62 , a purge control section  64 , and an air discharge control section  65 . 
     The flushing control section  62  controls an operation of the ink-jet head  4  and the carriage  2  at the time of carrying out the flushing operation. 
     The purge control section  64  controls an operation of the carriage  2 , the ascending and descending mechanism  19 , the switching unit  11 , and the suction pump  12  at the time of carrying out the suction purge operation of the purge cap  10 . 
     The air discharge control section  65  controls an operation of the carriage  2 , the ascending and descending mechanism  19 , the air discharge cap  8 , the switching unit  11 , and the suction pump  12  at the time of carrying out the air discharge operation of discharging air inside the ink tank  5  by the air discharge cap  8 . 
     The time measuring section  68  measures the time elapsed after each previous cleaning operation (the purge operation, the air discharge operation, and the flushing operation) by the recovery operation control section  63 , till the current time, and outputs to the recovery operation control section  63 . The recovery operation control section  63  drives the flushing control section  62 , the purge control section  64 , and the air discharge control section  65  at a predetermined cycle, based on the time measured by the time measuring section  68 . When an internal battery  72  has been mounted (installed) in the power supply unit  80 , the time measuring section  68  maintains a function of measuring the elapsed time for a certain fixed period by the internal battery  72  even after the power supply is switched OFF by disconnecting from the main power supply, However, thereafter, when the internal battery  72  is depleted, time data which has been measured is deleted (erased), and a state in which the elapsed time cannot be measured is assumed. Consequently, in this case, when the main power supply is connected once again in the fixed period after being disconnected from the main power supply, the time measuring section  68  continues a measuring operation. Moreover, when the internal battery is not mounted (installed) in the power supply unit  80 , as the power supply is turned OFF, the data of time measured is deleted (erased) immediately, and it is not possible to measure the elapsed time. 
     The display control section  66  outputs to the display section  92  a message signal to be displayed on the display section  92  of the operation panel section  90 . When the power supply is switched ON, the display control section  66  makes a judgment of an operation status of the time measuring section  68 . Here, when the time measuring section  68  is not capable of measuring the time, the display control section  66 , by controlling the display section  92 , displays on the display section  92  a message asking the user whether or not the cleaning operation is to be carried out. Moreover, the display control section  66 , by controlling the display section  92 , displays on the display section  92  a message asking the user whether or not the test printing is to be carried out, and whether or not the cleaning operation is to be carried out according to a result of the test printing. 
     As shown in  FIG. 6 , firstly, when the power supply is switched ON (step A 1 ), an operation status of the time measuring section  68  is checked (step A 2 ). Here, by reading the elapsed time which has been measured, it is possible to check the operation status of the time measuring section  68 . Or, the operation status of the time measuring section  68  may be checked by checking whether the battery is depleted. When the battery is mounted in the printer, and the operation of the time measuring section  68  is continued even when the power supply of the printer is OFF, a judgment that the measurement of the elapsed time by the time measuring section  68  is possible (has been carried out) is made (Yes at step A 2 ). At this time, even after the power supply of the printer is switched ON, based on the time measured by the time measuring section  68 , the recovery operation control section  63 , drives the flushing control section  62 , the purge control section  64 , and the air discharge section  65  at a predetermined cycle respectively. 
     On the other hand, when the battery has been depleted, or when the battery has not been installed in the apparatus, the operation of the time measuring section  68  is stopped, and the time elapsed after the previous recovery operation has not been known (is unknown) (No at step A 2 ). In this case (No at step A 2 ), the display control section  66 , displays on the display section  92  a message ‘Cleaning has been recommended. Would you like to carry out cleaning?’ as shown in  FIG. 2B  (step A 3 ). Accordingly, the display control section  66  asks the user, whether or not to carry out the cleaning operation. 
     When the user inputs ‘Yes’ signal from the input section  91  seeking to carry out the cleaning operation (Yes at step A 4 ), the recovery operation control section  63  makes the purge control section  64  and the air discharge control section  65  carry out the suction purge operation and the air discharge operation respectively as the cleaning operation (step A 5 ). Concretely, the purge control section  64  and the air discharge control section  65  connect the air discharge cap  8  and the air discharge channels  7   a  to  7   d , and cover the nozzles  25  by the purge cap  10 . Further, (the purge control section  64  and the air discharge control section  65 ) connect the air discharge cap  8  and the suction pump  12  by the switching unit  11 , and discharge the air accumulated in an upper portion of the ink tanks  5   a  to  5   d . Thereafter, the purge cap  10  and the suction pump  12  are connected by the switching unit  11 . Further, the suction purge operation of sucking the ink from the nozzle  25  and discharging is carried out. 
     When the user inputs ‘No’ signal from the input section  91  seeking not to carry out the cleaning operation (No at step A 4 ), a message ‘There is possibility that printing is unstable. Would you like to carry out test printing?’ is displayed on the display section  92  (step A 6 ), and asks the user whether or not the test printing is to be carried out. When the user inputs ‘No’ signal for not carrying out the test printing from the input section  91  of the PC (operation panel section)  90  (No at step A 7 ), the current sequence is terminated without carrying out the test printing. 
     When the user inputs ‘Yes’ signal seeking to carry out the test printing, from the input section  91 , the recording (image forming) control section  61  controls the ink-jet head  4 , the main scanning unit, and the transporting unit, and performs the test printing of forming a predetermined image pattern on the paper (step A 8 ). Moreover, the recording (image forming) control section  61  displays a message ‘Is result of test printing favorable?’ on the display section  92 , and asks the result of test printing to the user (step A 9 ). When the user makes a judgment that the result of the test printing is favorable, and inputs ‘Yes’ signal from the input section  91  (Yes at step A 10 ), the current sequence is terminated without carrying out the cleaning operation. When the user makes a judgment that the result of the test printing is not favorable and inputs ‘No’ signal (No at step A 10 ), the recovery operation control section  63  makes the purge control section  64  and the air discharge control section  65  carry out the cleaning operation similarly as in step A 5  (step A 11 ). 
     According to the ink-jet printer  1  according to the first embodiment described above, after it has become impossible to measure the elapsed time by the time measuring section  68  due to the power supply being OFF, when the power supply is switched ON, the controller  60  displays a message of whether or not the cleaning operation is to be carried out on the display section  92 . By displaying the message, the user is able to select by own will whether the cleaning operation is to be carried out. When a system environment is such that the power supply is switched ON and OFF frequently, and when the time for which the time could not be measured by the time measuring means is short due to a reason such that the power supply is switched OFF temporarily for moving the printer, normally it is not necessary to carry out the cleaning operation. Since the user is capable of selecting at own will, as to whether the cleaning operation is to be carried, in such case, it is possible to make an arrangement such that the cleaning operation is not carried out. 
     Moreover, since the cleaning operation is carried out only when it has been sought by the user from the input section  91 , it is possible to solve problems such as a waiting time for the unnecessary cleaning operation, and a wasteful consumption of ink. 
     Second Embodiment 
     Next, an ink-jet printer according to a second embodiment of the present invention will be described below by referring to  FIG. 7 . In the second embodiment, the cleaning operation is to be carried out according to the number of days for which the power supply is OFF. The main body portion of the ink jet printer in  FIG. 1  to  FIG. 4 , and the block diagram in  FIG. 5  are similar (even for the second embodiment). 
     As shown in  FIG. 7 , firstly, when the power supply is switched ON (step B 1 ), the operation status of the time measuring section  68  is checked (step B 2 ). Steps up to here being same as steps A 1  and A 2 , the description thereof in detail is omitted. On the other hand, when the time elapsed after the previous recovery operation is unknown (No at step B 2 ), a message ‘Has power supply been OFF for less than 30 days?’ as shown in  FIG. 2C  is displayed on the display section  92  (step B 3 ). In this manner, the number of days for which the power supply has been OFF, in other words, the time elapsed since the power supply has been switched OFF is asked to the user. 
     When the user inputs ‘Yes’ signal from the input section  91  (Yes at step B 4 ), the current sequence is terminated without carrying out the cleaning operation. When the user inputs ‘No’ signal from the input section  91  (No at step B 4 ), a message ‘Has power supply been OFF for more than 30 days but less than 60 days?’ is displayed on the display section  92  (step B 5 ), and asks the user the number of days for which the power supply has been OFF. 
     When the user inputs ‘Yes’ signal from the input section  91  (Yes at step B 6 ), the recovery operation control section  63  makes the purge control section  64  and the air discharge control section  65  carry out the cleaning operation (step B 7 ), and the content of the cleaning operation is same as in the steps A 5  and A 11  in the first embodiment. When the user inputs ‘No’ signal from the input section  91  (No at step B 6 ), the recovery operation control section  63  makes the purge control section  64  and the air discharge control section  65  carry out a powerful (intensive) cleaning operation (step B 8 ). At this time, in the powerful cleaning operation carried out at step B 8 , the number of days for which the power supply has been OFF being large (more), an amount of suction by the suction purge and the air discharge purge is increased as compared to the amount of suction in the cleaning operation carried out at step B 7 . 
     It is possible to display a message ‘Input number of days for which the power supply was OFF’ instead of the abovementioned message, and to input the number of days from the input section  91  by the user, and to control the presence or absence (execution) and the magnitude (the degree) of the jetting function recovery operation based on the magnitude of the figure (number of days). 
     According to the ink-jet printer  1  of the second embodiment as described above, when the power supply is switched ON after the measuring of the elapsed time by the time measuring section  68  becomes impossible due to the power supply of the printer being switched OFF, the controller  60  makes display a message asking the user a period for which the power supply was OFF. Accordingly, the controller  60  is capable of finding as to approximately how much time has elapsed after the power supply was switched OFF, and based on this time, it is possible to control the cleaning operation by the recovery operation control section  63 . 
     Moreover, by not carrying out the cleaning operation when the period for which the power supply was OFF, it is possible to do away with the dissatisfaction of the user that the unnecessary cleaning operation is carried out (that the cleaning operation is carried out unnecessarily). 
     Furthermore, by changing the degree (intensity) of cleaning according to a length of the period for which the power supply was OFF, it is possible to recover the jetting function of the ink-jet head irrespective of the drying of ink. 
     In the first embodiment and the second embodiment, when the user has switched the power supply ON for the first time after purchasing the ink-jet printer, it is preferable to make a setting to carry out a suction operation for infusing the ink to the ink-jet head from the ink cartridge based on a detection of installation of the new ink cartridge, without carrying out the abovementioned control. 
     Moreover, it is also possible to make an arrangement such that, in a state in which the power supply is ON continuously, based on the measurement of time by the time measuring section  68 , the controller  60  not only performs the jetting function automatically, but also when it has reached a time at which the jetting function recovery operation is to be carried out, or when it&#39;s close to the time at which the jetting function recovery operation is to be carried out, the display section  92  displays it as a message, and the jetting function recovery operation is carried out when the user has given an instruction from the input section  91 . 
     Exemplary embodiments of the present invention have been described above. However, the present invention is not restricted to the embodiments described above, and various modifications which fairly fall within the basic teaching herein set forth are possible. For instance, it is also possible to make an arrangement in which, a set of an ink-jet printer and a personal computer are let to be an image forming apparatus, and the input section  91  and the display section  92  are substituted by a display and an input device such as a key board of a personal computer. 
     Moreover, in the first embodiment and the second embodiment, as the cleaning operation, the suction purge operation and the air discharge operation are carried out. However, the flushing operation may be included in the cleaning operation, and these operations may be carried out separately, or these operations may be carried out in combination arbitrarily. Furthermore, in the first embodiment and the second embodiment, the air discharge operation and the purge operation have been carried out by the suction pump. However, an arrangement may be made such that, a positive pressure is applied to the ink from a side of the ink cartridges  14   a  to  14   d , and the air discharge operation of pushing the air from the ink tanks  5   a  to  5   d  is carried out with the valve  17  open, and the purge operation of pushing the ink from the nozzles  25  is carried out with the valve  17  closed. 
     In the first embodiment, after the cleaning operation has been recommended, the cleaning operation is carried out upon making the user select whether (the cleaning operation is) to be executed. However, the cleaning operation is not required to be carried out necessarily, and only the user&#39;s attention may be called to carry out the cleaning operation. 
     In the second embodiment, the degree (intensity) of the cleaning operation by the recovery operation control section  63  has been changed according to the degree (length) of the period input from the input section  91 . However, the degree (intensity) of the cleaning operation may be changed according to the user&#39;s judgment, and the degree (intensity) of the cleaning operation may be the same irrespective of the degree (length) of the period. 
     Moreover, it is also possible to execute both the embodiments (the first embodiment and the second embodiment) in combination such as by displaying the message ‘Has power supply been OFF for less than 30 days’ at step B 3  in the second embodiment after displaying the message ‘Cleaning has been recommended. Would you like to carry out cleaning?’ at step A 4  in the first embodiment. 
     In the embodiments described above, the image forming apparatus has the time measuring section as the information retention mechanism. After the power supply of the image forming apparatus has been switched OFF, when the time measuring section cannot continue (fails to continue) to measure the time due to depletion of the battery, a message asking the necessity of the recovery operation is displayed for the user. However, the information retention mechanism used in the image forming apparatus of the present invention may not necessarily have a timer function such as a time measuring section. For example, the image forming mechanism (apparatus) may have an information retention mechanism such as a counter and a memory which retains various history information, and when the power supply of the image forming apparatus is switched ON, in a case of occurrence of any error in reading the information retained (stored) in the information retention mechanism, the message asking the necessity of the recovery operation may be displayed for the user as described above. Concretely, history information such as a size of printing data, number of jettings (number of dots) of ink droplets, the number of printing (images printed), a frequency of replacement of ink cartridge, and/or a frequency of paper jamming is retained in the information retention mechanism. At this time (In this case), when the power supply of the image forming apparatus is switched ON, and in a case in which, it is not possible to acquire this information retained in the information retention mechanism, or this information has an abnormal value distinctly, the message asking the necessity of the recovery operation may be displayed for the user as described above. 
     In the embodiments described above, the image forming apparatus has the display section (display mechanism) which displays a message for the user, and the input section (input mechanism) which inputs a reply (response) from the user. However, the image forming apparatus of the present invention is not restricted to this, and may have one of the display section and the input section, or may have both the display section and the input section. For example, a display such as a liquid-crystal display and/or an input device such as a key switch may be provided independently of the image forming apparatus. Even in such a case, the control mechanism of the image forming apparatus may be capable of sending and receiving a predetermined signal to and from the input device and/or the display (a signal such as a signal for displaying a message on the display and a signal for receiving a reply (response) from the user). 
     Furthermore, in the first embodiment and the second embodiment, examples in which the image forming apparatus of the present invention is applied to the ink-jet printer are shown. However, the present invention is also applicable to an apparatus such as an apparatus which manufactures a color filter of a liquid crystal display apparatus by applying a colorant in a predetermined pattern, and an apparatus which forms a wiring pattern of an electronic circuit by applying an electroconductive liquid in the wire form. 
     In the first embodiment and the second embodiment described above, the image forming apparatus has the controller, and the controller displays a message on the display section, and controls the recovery operation for the ink-jet head. However, even when it is an image forming apparatus which does not have the abovementioned controller, by the image forming apparatus being connected to a computer, it is possible that the computer performs various controls which are carried out by the controller in the first embodiment and the second embodiment described above. In that case, the computer may run (execute) a computer program which executes various controls which are carried out by the controller described above.