JP4144214B2 - Cleaning device, printing device, and cleaning method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning device for cleaning an ink discharge portion in a printing apparatus, an ink jet printer provided with the cleaning device, a computer program for causing the cleaning device to clean, a computer system having the ink jet printer, and a cleaning method.
[0002]
[Prior art]
An ink jet printer prints an image by ejecting ink from a plurality of nozzles provided in a print head. The nozzle may not eject ink normally due to an increase in ink viscosity or air bubbles, resulting in a portion that is not printed on the image (hereinafter referred to as dot missing), resulting in degradation of image quality. There is. In particular, when printing an image such as a photograph, if a missing dot occurs, an image with a desired image quality cannot be obtained, and ink and paper are wasted. As a means for eliminating such dot omission, a cleaning mechanism for cleaning the print head is provided. For cleaning, it is checked whether or not ink has been ejected to all nozzles in advance, and when nozzles that have not ejected ink are detected, or when a predetermined number of nozzles that have not ejected ink have been detected Automatically cleans the print head.
[0003]
For example, the cleaning mechanism can absorb nozzles with a strong suction force and lengthen the suction time so that it can cope with clogging that is difficult to resolve when left for a long time without printing. Some have a relatively high cleaning capability, and others are set to automatically perform cleaning at regular time intervals.
[0004]
[Problems to be solved by the invention]
Since cleaning takes a little time, it is desirable to give priority to shortening the printing time rather than preventing slight dot omission when printing a document as soon as possible or when printing a document of any image quality. . However, if the cleaning is performed in the same manner for any image quality requirement, the printing operation is interrupted by the cleaning that is not originally required for printing regardless of the image quality, and the time until the image is output becomes longer. In particular, when a plurality of images are output continuously, there is a problem that the throughput is significantly reduced and a lot of time may be wasted.
[0005]
In addition, cleaning is relatively rare because of its relatively high cleaning ability, but even if the nozzles that normally ejected ink before cleaning by cleaning the print head, after cleaning, There is a risk that the nozzles are adversely affected such that the ink is not ejected normally, and the image quality is deteriorated.
[0006]
The present invention has been made in view of such problems, and the object of the present invention is to reduce the printing time by eliminating unnecessary cleaning of the print head in accordance with the required image quality, and to improve the printing time. Cleaning device that suppresses the occurrence of adverse effects on nozzles, inkjet printer equipped with the cleaning device, computer program for causing the cleaning device to clean, computer system, and unnecessary cleaning of the print head corresponding to the required image quality Is to realize a cleaning method that shortens the printing time and suppresses adverse effects on good nozzles.
[0007]
[Means for Solving the Problems]
The main present invention includes an ink discharge inspection unit that inspects whether or not a plurality of ink discharge units form an image by discharging ink onto a medium, and is formed in the cleaning device that cleans the ink discharge unit. A cleaning device that sets a threshold value corresponding to the operation mode of the ink discharge unit corresponding to the image quality of an image, and determines whether or not to perform cleaning based on the threshold value and the inspection result of the ink discharge inspection means It is.
[0008]
Other features of the present invention will become apparent from the accompanying drawings and the description of this specification.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
=== Summary of disclosure ===
At least the following matters will be made clear by the description of the detailed description of the invention in this specification.
[0010]
Ink cleaning inspection device for inspecting presence / absence of ink discharge of a plurality of ink discharge portions for forming an image by discharging ink onto a medium, and corresponding to the image quality of the image formed in the cleaning device for cleaning the ink discharge portion The cleaning device is characterized in that a threshold value is set in accordance with the operation mode of the ink discharge unit and whether or not cleaning is performed is determined based on the threshold value and the inspection result of the ink discharge inspection means.
[0011]
According to such a cleaning device, the threshold value that is a criterion for determining whether or not cleaning is necessary is set according to the operation mode of the ink ejection unit corresponding to the image quality. It is possible to set a threshold value in accordance with the image quality level that can be realized with. That is, for example, in the case of the high-speed printing mode that is used when priority is given to the printing speed over the image quality, by setting the threshold value as a determination criterion at a low level, the number of times of cleaning is reduced, and time is wasted due to cleaning. It becomes possible to reduce. Here, in the inspection result by the ink discharge inspection means, if the ink is not discharged, the ink is discharged in addition to the case where the ink is not discharged due to clogging or the like. The case where it is determined that the ink is not discharged is also included. For example, if the amount of ink discharged is small and the discharged ink cannot be detected by the ink discharge inspection means, or the ink discharge direction differs from the normal direction for some reason, the ink passes through the inspection position of the ink discharge inspection means. The case where it did not do is mentioned.
[0012]
Further, the ink discharge inspection unit detects the number of non-operational ink discharge units that do not discharge ink, and the threshold value may be set based on the number of non-operational ink discharge units that are allowed according to the operation mode. Good.
[0013]
According to this cleaning device, even if a non-operating ink discharge portion is detected, cleaning is not performed if the number is acceptable in the operation mode of the ink discharge portion. Therefore, faster printing can be realized while maintaining the image quality that can be realized in the operation mode. Further, by reducing the number of times of cleaning, it is possible to suppress an adverse effect on a good ink discharge portion and wasteful consumption of ink.
[0014]
The ink ejection units are provided corresponding to a plurality of ink colors, respectively, and the threshold is set based on the number of non-operational ink ejection units allowed in accordance with the operation mode and ink color. Is desirable.
[0015]
In the case of color ink, even when dot missing occurs in the same manner, the degree of influence on the image differs depending on the ink color. Therefore, if a threshold value that is used as a criterion for determining whether or not cleaning is necessary is set according to the ink color, the allowable number of non-operating nozzles can be set large for an ink color in which dot missing is not noticeable. As a result, the number of cleanings can be reduced and the printing speed can be improved. Also, for ink colors where missing dots are conspicuous, by setting the allowable number of non-operating nozzles small, it is possible to avoid continuing printing with a large number of non-operating nozzles, thus providing high-quality images. Can do.
[0016]
Further, an allowable deviation amount of the actual ejection position of the ink ejected from the ink ejection section with respect to the ejection target position is set in accordance with the operation mode, and the ink ejection inspection unit is configured to detect the ink ejected from the ink ejection section. When the deviation amount of the actual ejection position with respect to the ejection target position is larger than the allowable deviation amount, the ink ejection unit may be determined as a non-operational ink ejection unit that does not eject ink.
[0017]
A nozzle that deviates more than the allowable deviation amount from the discharge target position is also determined as a non-operation nozzle. For this reason, not only missing dots due to non-operating nozzles, but also missing dots that occur due to large deviation from the ejection target position can be prevented, and a higher quality image can be provided.
[0018]
In addition, in the cleaning device for cleaning the ink discharge portion, the ink discharge inspection means for inspecting the presence / absence of ink discharge of a plurality of ink discharge portions that form images by discharging different colors of ink onto the medium is provided. A threshold value corresponding to the color may be set, and whether to perform cleaning may be determined based on the threshold value and the inspection result of the ink ejection inspection unit.
[0019]
According to such a cleaning apparatus, since the threshold value that is a criterion for determining whether or not cleaning is necessary is set according to the color of the ink, it is matched with the degree of influence on the image by the color of the ink that has not been ejected. The necessity of cleaning can be determined. For example, by setting a high threshold value for a color ink that has a large effect on an image, and setting a low threshold value for a color ink that has a small effect on an image, It is possible to reduce the number of times of cleaning when ink is not ejected, and to reduce waste of time due to cleaning.
[0020]
In addition, an ink discharge inspection unit that inspects whether or not a plurality of ink discharge portions form an image by discharging ink onto a medium, and in the cleaning device that cleans the ink discharge portion, according to the concentration of the ink A threshold value may be set, and whether to perform cleaning may be determined based on the threshold value and the inspection result of the ink ejection inspection means.
[0021]
According to such a cleaning device, since a threshold value that is a criterion for determining whether or not cleaning is necessary is set according to the density of the ink, even when ink is not ejected, on the printed image When low threshold ink is set for low density inks that are not easily noticeable and high threshold is set for high density inks that are easily noticeable on the image By reducing the number of cleanings, it is possible to reduce waste of time due to cleaning.
[0022]
In addition, in the cleaning device for cleaning the ink discharge unit, the ink discharge unit includes a plurality of ink discharge inspection units that inspect the presence / absence of ink discharge of a plurality of ink discharge units that discharge ink onto a medium to form an image. It may be arranged in a row, a threshold value corresponding to this row may be set, and it may be determined whether or not cleaning is performed based on this threshold value and the inspection result of the ink ejection inspection means.
[0023]
According to such a cleaning apparatus, since the threshold value is set for each column of the ink ejection unit, for example, by setting conditions such as ink characteristics for each column, it is possible to set according to the condition. That is, it is possible to reduce the cleaning time by inspecting ink ejection based on the threshold set for each column and cleaning for each column.
[0024]
In addition, an ink discharge state inspection unit that inspects the ink discharge states of a plurality of ink discharge units that form an image by discharging ink onto a medium, and in the cleaning device that cleans the ink discharge unit, discharge from the ink discharge unit An allowable deviation amount of the actual ejection position of the ink to be ejected with respect to the ejection target position is set according to the operation mode of the ink ejection unit corresponding to the image quality of the image to be formed, and the inspection result of the ink ejection state inspection unit is Based on this, when it is determined that the deviation amount of the actual ejection position of the ink ejected from the ink ejection unit with respect to the ejection target position is larger than the allowable deviation amount, the ink ejection unit may be cleaned.
[0025]
According to this cleaning device, even if a deviation occurs in the actual ejection position of the ink ejected from the ink ejection unit with respect to the ejection target position, the deviation amount is an allowable amount allowed in the operation mode of the ink ejection unit. Do not clean. That is, unnecessary printing can be eliminated and faster printing can be realized, and the required image quality can be maintained. Further, by reducing the number of times of cleaning, it is possible to suppress an adverse effect on a good ink discharge portion and wasteful consumption of ink.
[0026]
Further, the ink discharge section may be provided corresponding to a plurality of ink colors, and the allowable deviation amount may be set according to the operation mode and the ink color.
[0027]
If the permissible misregistration amount, which is the criterion for determining whether cleaning is necessary, is set according to the ink color, the criteria for cleaning can be changed between the ink color that makes dot missing difficult to notice and the ink color that stands out easily. As compared with the case where the same allowable deviation amount is provided in FIG. 2, the printing speed can be improved without degrading the image quality level.
[0028]
In the cleaning device for cleaning the ink discharge portion, the ink discharge state inspection unit that inspects the ink discharge state of a plurality of ink discharge portions that form images by discharging different color inks onto the medium. An allowable deviation amount of the actual ejection position of the ink ejected from the ejection section with respect to the ejection target position is set according to the color of the ink, and ejected from the ink ejection section based on the inspection result of the ink ejection state inspection unit. When it is determined that the deviation amount of the actual ink ejection position relative to the ejection target position is larger than the allowable deviation amount, the ink ejection portion may be cleaned.
[0029]
According to such a cleaning apparatus, since the allowable deviation amount that is a criterion for determining whether or not cleaning is necessary is set according to the color of the ink, the degree of influence on the image by the color of the ink that has not been ejected It is possible to determine whether or not cleaning is necessary. For example, by setting a small allowable deviation amount for ink with a color that has a large influence on an image and setting a large allowable deviation amount for ink with a color that has a small influence on an image, the influence on the image It is possible to reduce the number of cleanings when ink of a small color is not ejected, and to reduce the waste of time due to cleaning.
[0030]
In addition, an ink discharge state inspection unit that inspects the ink discharge states of a plurality of ink discharge units that form an image by discharging ink onto a medium, and in the cleaning device that cleans the ink discharge unit, discharge from the ink discharge unit Ink discharged from the ink discharge portion is set based on the inspection result of the ink discharge state inspection means, and an allowable deviation amount of the actual discharge position with respect to the discharge target position is set according to the ink density. When it is determined that the deviation amount of the actual ejection position with respect to the ejection target position is larger than the allowable deviation amount, the ink ejection unit may be cleaned.
[0031]
According to such a cleaning apparatus, since the allowable deviation amount serving as a determination criterion for determining whether or not cleaning is required is set according to the density of the ink, the printed image can be printed even when the ink is not ejected. By setting a large allowable deviation amount for low-concentration ink that is difficult to see above, and by setting a small allowable deviation amount for high-concentration ink that tends to stand out on the image, It is possible to reduce the number of cleanings when low ink is not ejected, thereby reducing waste of time due to cleaning.
In the cleaning device for cleaning the ink discharge portion, the ink discharge state inspection unit that inspects the ink discharge state of the plurality of ink discharge portions that form an image by discharging ink onto the medium includes a plurality of the ink discharge portions. The allowable deviation amount of the actual ejection position of the ink ejected from the ink ejection section with respect to the ejection target position is set according to the column, and the inspection of the ink ejection state inspection unit is performed. Based on the result, when it is determined that the deviation amount of the actual ejection position of the ink ejected from the ink ejection unit with respect to the ejection target position is larger than the allowable deviation amount, the ink ejection unit may be cleaned.
[0032]
According to such a cleaning apparatus, since the allowable deviation amount is set for each column of the ink ejection unit, for example, by setting the conditions such as the ink characteristics for each column, the setting can be set according to the condition. In other words, it is possible to reduce the cleaning time by inspecting the ink discharge based on the allowable deviation amount set for each column and cleaning the column.
[0033]
The ink jet printer further includes an ink discharge inspection unit that inspects whether or not a plurality of ink discharge units form an image by discharging ink onto a medium, and includes a cleaning device that cleans the ink discharge unit. The apparatus sets a threshold value corresponding to the operation mode of the ink ejection unit corresponding to the image quality of the image to be formed, and determines whether or not to perform cleaning based on the threshold value and the inspection result of the inspection unit It is also possible to realize an ink jet printer provided with a computer program that causes the cleaning device to perform cleaning.
[0034]
An ink jet printer comprising: an ink ejection state inspection unit that inspects an ink ejection state of a plurality of ink ejection units that eject ink onto a medium to form an image; and a cleaning device that cleans the ink ejection unit. The cleaning device sets an allowable deviation amount of the actual ejection position with respect to the ejection target position of the ink ejected from the ink ejection section according to the operation mode of the ink ejection section corresponding to the image quality of the image to be formed, When it is determined that the deviation amount of the actual ejection position with respect to the ejection target position of the ink ejected from the ink ejection unit is larger than the allowable deviation amount based on the inspection result of the ink ejection state inspection unit, the ink ejection unit An inkjet printer, and a cleaning device for the cleaning device A computer program to be also feasible.
[0035]
In addition, a computer main body, a display device connected to the computer main body, and ink discharge inspection means for inspecting the presence or absence of ink discharge of a plurality of ink discharge portions that discharge ink onto a medium to form an image are formed. A cleaning device that sets a threshold value corresponding to the operation mode of the ink ejection unit corresponding to the image quality of the image, and determines whether to clean the ink ejection unit based on the threshold value and the inspection result of the inspection unit A computer system having a printer connected to the computer main body can also be realized.
[0036]
The ink further includes a computer main body, a display device connected to the computer main body, and ink discharge state inspection means for inspecting ink discharge states of a plurality of ink discharge portions that discharge the ink onto a medium to form an image. An ink discharge state inspection unit that sets an allowable deviation amount of an actual discharge position with respect to a discharge target position of ink discharged from the discharge unit according to an operation mode of the ink discharge unit corresponding to the image quality of the image to be formed. The cleaning device that cleans the ink ejection unit when it is determined that the deviation amount of the actual ejection position of the ink ejected from the ink ejection unit with respect to the ejection target position is larger than the allowable deviation amount based on the inspection result A computer system having a printer connected to the computer main body can also be realized.
[0037]
Also formed in a cleaning method using an ink discharge inspection means for inspecting the presence or absence of ink discharge of a plurality of ink discharge portions that form an image by discharging ink onto a medium, and using a cleaning device for cleaning the ink discharge portion. A step of setting a threshold value according to an operation mode of the ink discharge unit corresponding to the image quality of the image, inspecting the presence or absence of ink discharge by the ink discharge inspection means, and cleaning based on the inspection result and the threshold value. It is also possible to implement a cleaning method having a step of determining whether or not.
[0038]
Further, in the cleaning method using an ink discharge inspection means for inspecting the presence or absence of ink discharge of a plurality of ink discharge portions that form an image by discharging ink onto a medium, and using the cleaning device for cleaning the ink discharge portion, the ink An allowable deviation amount of the actual ejection position of the ink ejected from the ejection section with respect to the ejection target position is set according to the operation mode of the ink ejection section corresponding to the image quality of the image to be formed, and the ink ejection inspection unit When it is determined that the deviation amount of the actual ejection position with respect to the ejection target position of the ink ejected from the ink ejection unit is larger than the allowable deviation amount based on the inspection result of the ink ejection presence / absence, A cleaning method including a step of cleaning the ink discharge portion can also be realized.
[0039]
<<<< first embodiment >>
=== General Configuration of Printing Apparatus ===
FIG. 1 is a schematic perspective view showing a main configuration of a color inkjet printer 20 having a cleaning device as an embodiment of the present invention. The printer 20 includes a paper stacker 22 on which the printing paper P is stacked, a paper feeding roller 24 driven by a step motor (not shown), a platen plate 26, and a paper feeding direction parallel to the printing paper P (sub-scanning). The carriage 28 driven in a direction perpendicular to the direction (main scanning direction), a step motor 30 for driving the carriage 28, a timing belt 32 for transmitting the power of the step motor 30 to the carriage 28, and guiding the carriage 28. And a guide rail 34 for the purpose. On the carriage 28, a print head unit 36 having a large number of nozzles for ejecting ink onto the printing paper P is mounted.
[0040]
A nozzle inspection unit 40 and a waste ink receiver 46 are provided on the side of the step motor 30 in the carriage 28 scanning range that is the standby position of the carriage 28. The waste ink receiver 46 is a container that receives ink ejected from the nozzles at the time of ink ejection determination, and a felt for preventing ink splashing is laid on the bottom thereof.
[0041]
The printing paper P is taken up by the paper feed roller 24 from the paper stacker 22 and is fed on the surface of the platen plate 26 in the sub-scanning direction. The carriage 28 is pulled by the timing belt 32 driven by the step motor 30 and moves in the main scanning direction along the guide rail 34.
[0042]
FIG. 2 is an explanatory diagram showing the overall configuration of the computer system including the printer 20. This computer system includes a printer 20, a host computer 100 to which the printer 20 is connected, a liquid crystal display (display device) 110 connected to the host computer 100, a keyboard 120 that forms an input device, and a mouse 130. .
[0043]
FIG. 3 is a block diagram showing an electrical configuration of the printer 20. The printer 20 includes a reception buffer memory 50 that receives a signal supplied from the host computer 100, an image buffer 52 that stores print data, a system controller 54 that controls the operation of the entire printer 20, a main memory 56, and a timer. 58.
[0044]
The system controller 54 includes a main scanning drive driver 61 that drives the carriage motor 30, a sub-scanning drive driver 62 that drives the paper feed motor 31, an inspection unit driver 64 that drives the nozzle inspection unit 40, and a print head. A head drive driver 66 that drives the unit 36 is connected. The paper feed motor 31 is also used as a motor for operating a nozzle suction mechanism 200 described later.
[0045]
The system controller 54 realizes various functions including an ink ejection determination function and a print head cleaning function by executing a computer program stored in the main memory 56.
[0046]
A computer program for realizing various functions of the system controller 54 is provided in a form recorded on a computer-readable recording medium such as a flexible disk or a CD-ROM. The host computer 100 can read the computer program from the recording medium and transfer it to the main memory 56 of the printer 20.
[0047]
The “recording medium” in the present invention includes a flexible disk, a CD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which a code such as a bar code is printed, an internal storage device (RAM) of a computer. And various media that can be read by a computer such as an external storage device.
[0048]
A printer driver (not shown) of the host computer 100 includes a print head unit 36 and the like corresponding to the print mode based on the print mode (high-speed print mode, high-quality print mode, high-definition print mode, etc.) designated by the user. Various parameter values defining the printing operation mode are determined. Here, the high-speed printing mode is a printing mode in which the printing speed is given priority over the image quality, the high-quality printing mode is a printing mode in which the image quality is relatively emphasized, and the high-definition printing mode is a higher-quality image. This is the print mode used when obtaining. In these printing modes, the higher the image quality, the longer the time required for printing.
[0049]
The printer driver further generates print data for performing printing in the print mode based on these parameter values, and transfers the print data to the printer 20. The transferred print data is temporarily stored in the reception buffer memory 50. In the printer 20, the system controller 54 reads necessary information from the print data from the reception buffer memory 50, and based on this, sends a control signal to each driver.
[0050]
The image buffer 52 stores print data of a plurality of color components obtained by separating the print data received by the reception buffer memory 50 for each color component. The head drive driver 66 reads the print data of the color components from the image buffer 52 in accordance with the control signal from the system controller 54, and drives the nozzle array for each color provided in the print head unit 36 in accordance with this.
[0051]
=== Configuration and Operation Principle of Ink Ejection Inspection Unit ===
FIG. 4 is a block diagram showing an electrical configuration of the nozzle inspection unit 40 that constitutes an ink ejection inspection unit. The nozzle inspection unit 40 compares the ink discharge determination unit 41 that generates a detection pulse in accordance with the shielding of the laser light L by the ink, and the time interval of the detection pulse and a predetermined threshold (described later). Then, a detection pulse determination unit 42 that performs a predetermined determination and counts up the result, and a nozzle specification unit 43 that specifies a non-operating nozzle (a nozzle that does not normally eject ink) based on the counted result of the determination. With.
[0052]
A timer 45 is connected to the detection pulse determination unit 42. The detection pulse determination unit 42 uses a timer 45 to measure the time interval between pulses generated by the ink discharge determination unit 41.
[0053]
=== Configuration and Operation Principle of Ink Ejection Determination Unit ===
FIG. 5 is an explanatory diagram illustrating the configuration of the ink discharge determination unit 41 and the principle of the determination method, and the print head unit 36 is viewed from the lower surface side. In FIG. 5, a print head unit 36 including three print heads 36 a, 36 b, and 36 c, and a light emitting unit 41 a and a light receiving unit 41 b included in the ink ejection determination unit 41 are illustrated. The ink discharge determination unit 41 determines whether ink is discharged by blocking the light from the light emitting unit 41a.
[0054]
The three print heads 36a, 36b, 36c are each provided with a nozzle array for six colors divided into two colors, and the nozzle array for each color is composed of 180 nozzles (ink ejection units). ing.
[0055]
A black ink nozzle array K for discharging black ink and a dark cyan ink nozzle array C for discharging dark cyan ink are provided on the lower surface of the first print head 36a, and the lower surface of the second print head 36b. Includes a light cyan ink nozzle array L for discharging light cyan ink. _C And a light magenta ink nozzle array L for discharging light magenta ink. _M And a dark magenta ink nozzle array M for ejecting dark magenta ink and a yellow ink nozzle array Y for ejecting yellow ink are provided on the lower surface of the third print head 36c.
Each nozzle constituting each nozzle array is aligned along the sub-scanning direction SS. At the time of printing, droplet-like ink is ejected from each nozzle while the print head unit 36 moves in the main scanning direction MS together with the carriage 28 (FIG. 1).
[0056]
The light emitting unit 41a is a laser diode that emits a light flux having an outer diameter of about 1 mm or less. The directions of the light emitting unit 41a and the light receiving unit 41b are adjusted so that the traveling direction of the laser light L is slightly inclined from the sub-scanning direction SS.
[0057]
In determining ink ejection, the print head unit 36 is slowly reciprocated in the main scanning direction at a constant speed while emitting the laser beam L, and the nozzles to be judged are sequentially driven to eject ink. Execute. FIG. 6 shows an example of a nozzle block that is a determination target for each reciprocating scan of the print head unit 36. In this example, the ink ejection determination for all the nozzles is completed while the print head unit 36 reciprocates four times in the main scanning direction. As shown in FIG. 6, in the first movement of the print head unit 36 in one direction, one nozzle array (K, L) of each print head 36a, 36b, 36c is used. _C , M), # 1, # 5, # 9,..., # 177, every three nozzles are set as one nozzle block, and ink ejection determination is executed for this nozzle block. When ink ejection from the nozzles is detected, the next movement in the return direction is adjacent to each of the same nozzle array, such as # 2, # 6, # 10,. A nozzle block composed of nozzles located is a determination target. Therefore, when two reciprocations are made, ink ejection determination is executed for all nozzles of the nozzle array for three colors. Thereafter, similarly, the carriage 28 reciprocates twice, and the ink ejection determination for all the nozzles is completed.
[0058]
At this time, due to the arrangement of the nozzle array in the print head unit 36 mounted on the carriage 28, the black ink K and the light cyan ink L in the forward direction during the previous two reciprocating scans. _C , Dark magenta ink M, then dark magenta ink M and light cyan ink L in the sub direction. _C Ink ejection determination is executed in the order of the nozzles that eject the black ink K. In the next two round trips, dark cyan ink C and light magenta ink L in the forward direction _M , Yellow ink Y, yellow ink Y, and light magenta ink L in the sub direction. _M Ink ejection determination is executed in the order of the nozzles that eject the dark cyan ink C.
[0059]
=== Method for Specifying Non-Operating Nozzle Array ===
7 and 8 are explanatory diagrams showing ink ejected into the beam of the laser light L and signal waveforms for detecting the ink. Here, for ease of explanation, the operation of one row of nozzle arrays will be described. One nozzle array is shown on the left side of FIG. 7A, and the ink and laser beam L emitted from the nozzle array are shown on the right side.
[0060]
7B and 7C show waveforms of ink detection pulses generated by the ink discharge determination unit 41 in accordance with the shielding of the laser beam L by ink. In the state of FIG. 7, the ink ejected from the # 1 nozzle blocks the laser beam L, and six ink detection pulses are generated accordingly. FIG.7 (c) expands the waveform of FIG.7 (b). As can be seen from this figure, the plurality of ink detection pulses for the same nozzle occur at a short time interval ti corresponding to the ink ejection cycle.
[0061]
FIG. 8 shows a state after a little time has elapsed from FIG. In the state of FIG. 8, the ink ejected by the # 5 nozzle blocks the laser beam L. The rising edge of the first detection pulse by the ink ejected from the # 5 nozzle is detected after the time tn has elapsed from the falling edge of the last detection pulse by the # 1 nozzle. The time tn is a time interval between ink detection pulses generated according to ink ejected by different inspection target nozzles. This time tn can be freely set by selecting a nozzle that ejects ink as an inspection target. In this example, the # 2, # 3, and # 4 nozzles are excluded from the inspection target, and the # 5 nozzle is selected as the inspection target nozzle adjacent to the # 1 nozzle. As described above, the time tn is set larger than the time ti, which is the time interval of detection pulses generated according to the ink ejected from the same nozzle, whereby the same nozzle ejects the same nozzle. It is possible to determine whether the generated ink is ejected from different nozzles. The details of the method for selecting the inspection target nozzle will be described later.
[0062]
FIG. 9 is an explanatory diagram showing signal waveforms over a plurality of nozzle arrays. The signal waveform shown in FIG. 9A also shows a waveform after a little time has elapsed from FIG. 8B. FIG. 9B is an enlarged view of the signal waveform shown in FIG. Here, the time tc is a time during which the laser light L relatively moves between the nozzle array. As described above, the time ti is a time interval between detection pulses generated according to the ink ejected from the same nozzle. The time tn is a time interval between ink detection pulses generated according to ink ejected by different inspection target nozzles. The times tn and tc can be set by selecting the inspection target nozzle or the inspection target nozzle array. Details of this setting will be described later.
[0063]
FIG. 10 is a flowchart showing a process for specifying a nozzle array in which non-operating nozzles exist.
[0064]
In step S <b> 101, the main scanning drive driver 61 that has received a command from the system controller 54 drives the carriage motor 30 to start main scanning of the carriage 28. In the ink discharge determination of the present embodiment, the print head 36 and the ink discharge determination unit 41 are relatively moved by moving the carriage 28 on which the print head unit 36 is mounted in the main scanning direction. In step S102, laser irradiation is started. For example, when at least one nozzle of the print head unit 36 reaches the vicinity of the laser beam L, the laser irradiation starts at a timing at which ink can be detected stably.
[0065]
In step S103, the plurality of nozzles to be inspected start ink ejection. At this time, when laser irradiation is performed, ink is always ejected from a plurality of nozzles. After the start of ink ejection, the laser beam L enters the area where the nozzles provided in the print head unit 36 eject ink.
[0066]
In step S104, the detection pulse determination unit 42 counts up the determined number of times. This determination is performed by comparing the time interval of detection pulses generated by the ink discharge determination unit 41 with a predetermined threshold value. This threshold will be described later.
[0067]
FIG. 11 is a flowchart showing a process for counting the number of determinations. In step S <b> 201, the ink ejection determination unit 41 generates the first ink detection pulse according to the first shielding of the laser beam L by ink. This detection pulse is sent from the ink ejection determination unit 41 to the detection pulse determination unit 42 (FIG. 4). In step S202, the detection pulse determination unit 42 starts the timer 45 in response to the falling edge (FIG. 7) of the ink detection pulse. Thereby, the measurement of the time between detection pulses is started.
[0068]
In step S203, the ink ejection determination unit 41 generates the next ink detection pulse in response to the new shielding of the laser light L by the ink. The detection pulse determination unit 42 that has received this detection pulse stops the timer 45 in response to the rising edge of the ink detection pulse (S204). Thereby, the time ti from the falling edge of the first detection pulse to the rising edge of the next detection pulse (FIG. 7) can be measured. This time ti is a time interval between detection pulses generated according to the ink ejected from the same nozzle. In this specification, the actual measurement value by the timer is tm.
[0069]
In step S205, the detection pulse determination unit 42 performs a first determination as to whether or not the time tm measured by the timer is greater than or equal to the first threshold t1. The first threshold value t1 determines whether consecutive detection pulses are generated according to the ink ejected from the same nozzle or generated according to the ink ejected from different nozzles. This is the reference time. The first threshold value t1 is always set to be larger than the time ti between detection pulses caused by the same nozzle and smaller than the time tn between detection pulses caused by different nozzles.
[0070]
When the time tm measured by the timer is smaller than the first threshold t1, the detection pulse determination unit 42 determines that consecutive detection pulses are caused by the same nozzle, and proceeds to step S212. In step S212, the timer is reset, and the timer is started again at the falling edge of the detection pulse (step S202). When the time tm measured by the timer is equal to or greater than the first threshold value t1, the detection pulse determination unit 42 determines that the detection pulse is due to ink ejected from a different nozzle, and the process proceeds to step S206.
[0071]
In step S206, the detection pulse determination unit 42 counts up the determination result. This counted up number is the number of determinations that successive detection pulses are due to different nozzles, and therefore corresponds to a number that is one less than the number of nozzles that are inspected and are operating normally. Will do. For example, when the count-up number is 1, two different operating nozzles are detected.
[0072]
In step S207, the detection pulse determination unit 42 performs a second determination as to whether or not the time tm measured by the timer is equal to or greater than the second threshold t2. This second threshold value t2 is always larger than the time interval tn between different nozzles in the same nozzle array (FIG. 9) and smaller than the time interval tc between nozzles belonging to different nozzle arrays. It is set to become. When tm is smaller than t2, the detection pulse determination unit 42 determines that there is no non-operating nozzle region between the two detected nozzles, and proceeds to step S212. Here, the “non-operating nozzle region” refers to a region where the inspection target nozzle is a non-operating nozzle. On the other hand, when the time tm measured by the timer is equal to or greater than the second threshold t2, the process proceeds to step S208. When the time tm measured by the timer is equal to or greater than the second threshold t2, there is either a non-operating nozzle region or an interval between the nozzle array and the nozzle array between the two detected nozzles. It will be.
[0073]
In step S208, the detection pulse determination unit 42 performs a third determination as to whether or not the time tm measured by the timer is equal to or greater than a third threshold t3. The third threshold value t3 is for determining whether or not the nozzle array has been changed during the main scanning. That is, continuous detection pulses are generated according to ink ejected by nozzles belonging to the same nozzle array, or generated according to ink ejected by nozzles belonging to different nozzle arrays. This is a reference time for determining whether or not. The third threshold value t3 is always set as a time smaller than the time tc (FIG. 9).
[0074]
When the time tm measured by the timer is smaller than the third threshold value t3, the detection pulse determination unit 42 is caused by the same nozzle and the non-operating nozzle region exists in the nozzle array. Judgment is made. This determination is called non-operation determination. On the other hand, when the time tm measured by the timer is equal to or greater than the third threshold value t3, the detection pulse determination unit 42 determines that successive detection pulses are caused by nozzles belonging to different nozzle arrays. This determination is called nozzle array detection determination.
[0075]
In step S209, the detection pulse determination unit 42 counts up the determination that there is a non-operating nozzle region. However, since the number of non-operating nozzles can be detected by this determination, when there are a plurality of non-operating nozzles in succession, the number of non-operating nozzles can be obtained directly from this determination result. I can't.
[0076]
In step S210, the detection pulse determination unit 42 counts up the determination that it has moved to another nozzle array. Since the number of determinations is the number of determinations that are detection pulses caused by nozzles belonging to different nozzle arrays, it corresponds to a number that is 1 less than the number of detected nozzle arrays.
[0077]
In step S210, the nozzle inspection unit 40 stores the number of operating nozzles counted up in step S206 in the main memory 56 (FIG. 4) as inspection target nozzles operating normally in the nozzle array. This process is performed via the inspection unit driver 64 and the system controller 54. When the completion of the storage is confirmed, the detection pulse determination unit 42 resets the count of the number of nozzles in order to count up the number of nozzles of the next nozzle array. In this way, the nozzles to be inspected normally operating for each nozzle array are counted up.
[0078]
In step S213, the detection pulse determination unit 42 compares the number of detected nozzle arrays with the number of nozzle arrays to be inspected. As a result, when the number of detected nozzle arrays matches the number of nozzle arrays to be inspected, it is determined that the last nozzle array to be inspected in the main scan is being inspected. . In step S208 after this determination, even when the next detection pulse is not detected, the counting of the determination count ends when the time tm measured by the timer becomes equal to or greater than the third threshold t3. Then, the process proceeds to step S105 (FIG. 10). On the other hand, when the number of detected nozzle arrays is smaller than the number of nozzle arrays to be inspected, the process proceeds to step S212.
[0079]
In step S212, the timer is reset as described above, and the timer is started again at the falling edge of the detection pulse (step S202).
[0080]
When the total number of determinations shown in FIG. 11 is completed, the process proceeds to step S105 (FIG. 10). In step S105, the nozzle specifying unit 43 determines a nozzle array having non-operating nozzles. This decision starts with
(1) A determination that “continuous detection pulses are generated according to ink ejected by nozzles belonging to the same nozzle array”;
(2) “Comparison between the number of detected operating nozzles and the number of inspection target nozzles”;
Can be determined from “Sequential detection pulses are generated according to the ink ejected by the nozzles belonging to the same nozzle array” is determined in step S208 because the time tm is smaller than the third threshold value t3. . Thereby, first, a nozzle array is specified. The “comparison between the number of detected operating nozzles and the number of inspection target nozzles” is determined by comparing the number of determinations that the time tm is equal to or greater than the first threshold t1 (step S205) with the number of inspection target nozzles. As a result, when the number of operating nozzles detected in step S205 is smaller than the number of nozzles to be inspected, it is understood that there are non-operating nozzles in the specified nozzle array.
[0081]
In step S105, the nozzle specifying unit 43 further determines a nozzle array having non-operating nozzles by another method. This determination uses non-operating nozzle determination that “there is a non-operating nozzle region”. “There is a non-operating nozzle area” is determined by the time tm being equal to or longer than the second threshold t2 (step S207) and smaller than the third threshold t3 (step S208). This also makes it possible to specify the nozzle array in which the non-operating nozzle array exists. As a result, if the logical sum of the result of the above method based on the comparison of the number of nozzles and the result of this method for directly inspecting the ejection of ink is taken, oversight of non-operating nozzles can be reduced. That is, if it is determined that there is a non-operating nozzle by at least one of the methods, the nozzle specifying unit 43 determines that there is a non-operating nozzle.
[0082]
FIG. 12 is a table showing an example of the total number of determination times. This tabulation result is a tabulation of inspection results obtained by a plurality of main scans. The number of nozzles to be inspected is the number of all nozzles to be inspected, and in this example, all nozzles equipped in the print head unit 36 are the nozzles to be inspected. Black, cyan, etc. in each table mean a nozzle array of each color. The nozzle array is specified based on the number counted in step S210 (FIG. 11) and the predetermined nozzle array inspection order. That is, since the arrangement of the nozzle array provided in the print head 36 and the ink color ejected from the nozzle array are set in advance, the scanning direction of the carriage 28 is sent from the system controller 54 to the main scanning drive driver 61. By specifying from the signal, it is possible to determine which ink color is ejected by the nozzle array in which the non-operating nozzle is detected. For example, in the ink ejection determination performed by the carriage 28 reciprocating four times, the nozzle array detected at the beginning of the first reciprocation is a black ink nozzle, and each time it is detected that the nozzle array has changed, a light cyan The ink nozzle and the dark magenta ink nozzle are sequentially determined. Further, at the time of the fourth reciprocating return scan, it is determined that the first detected nozzle array is the yellow ink nozzle, and then sequentially the light magenta ink nozzle and the dark cyan ink nozzle.
[0083]
FIG. 12A shows a result assumed to be counted by the inspection method of this embodiment when there is no non-operating nozzle. As described above, in this example, since all the nozzles provided in the print head unit 36 are the inspection target nozzles, the number of inspection target nozzles in each nozzle array is 180. On the other hand, the number of detected operating nozzles is 180 in all the nozzle arrays. Thus, the number of nozzles detected by the ejected ink matches the number of nozzles to be inspected, which indicates that there is no non-operating nozzle.
[0084]
The number of non-operating nozzle areas is zero for any nozzle array. This means that there is no region where no nozzles exist in any nozzle array. Thus, the presence or absence of the non-operating nozzle can be confirmed by these two methods.
[0085]
FIG. 12B shows the inspection method of this embodiment when it is assumed that there is one non-operating nozzle in a nozzle that is not located at the end of the black ink nozzle array (hereinafter referred to as an end nozzle). This is a result that is assumed to be tabulated. Here, for example, in the example shown in FIG. 6, the end nozzles of the first group of the yellow nozzle array are # 1, # 177 nozzles, and the end nozzles of the fourth group of the nozzle array are used. The nozzles are # 4 and # 180 nozzles.
[0086]
In the example shown in FIG. 12B, the number of nozzles detected in the black ink nozzle array is one less than the number of nozzles to be inspected. The number of non-operating nozzle areas detected is also one for the black nozzle array. Thus, on the one hand, it shows that there is one non-operating nozzle in the black nozzle array, and on the other hand, it shows that there is one region with non-operating nozzles, and the alignment is taken.
[0087]
FIG. 12C shows a result assumed to be counted by the inspection method of this embodiment when it is assumed that there is one non-operating nozzle in the end nozzle of the nozzle array of cyan ink. In this example, in the cyan ink nozzle array, the number of detected operation nozzles is smaller by one than the number of nozzles to be inspected, as in the column of FIG. However, the non-operating nozzle area is not detected. Thus, on the one hand, it indicates that there is a non-operating nozzle in the nozzle array of cyan ink, and that there is no non-operating nozzle in a nozzle that is not an end nozzle.
[0088]
As described above, a nozzle array having non-operating nozzles is detected by measuring the interval between the ejected inks, and the number of detected nozzles (the number of detected operating nozzles) is compared with the number of nozzles to be inspected. Thus, the number of non-operating nozzles included in each nozzle array can be detected. That is, the number of non-operating nozzles can be detected corresponding to the ink color.
[0089]
Furthermore, it is preferable to confirm the operation of the end nozzles in advance prior to the inspection of all the nozzles. This is because the operation of the end nozzle can also be confirmed twice, so that the detection accuracy is further improved. The operation of the end nozzles can be confirmed by causing only the end nozzles to eject ink, detecting the operating nozzles, and matching the result of the counting with the number of the end nozzles.
[0090]
Here, an example of a method for specifying a nozzle array including non-operating nozzles has been described. However, the method is not limited to the above-described method as long as a nozzle array including non-operating nozzles can be specified.
[0091]
=== Nozzle cleaning ===
Next, the nozzle suction mechanism 200 that forms a nozzle cleaning mechanism in the printer 20 will be described.
[0092]
FIG. 13 is a conceptual diagram showing the configuration of the nozzle suction mechanism 200. The nozzle suction mechanism 200 includes a head cap 210, hoses 220a to 220f, and pump rollers 230a to 230f. In addition, since the structure and operation | movement of the hose 220a-220f and the pump rollers 230a-230f are the same, it demonstrates with the hose 220c and the pump roller 230c, and the overlapping description and illustration are abbreviate | omitted. As shown in FIG. 15, the inner space of the head cap 210 is partitioned into six suction chambers Va to Vf. When the head cap 210 is raised, the head cap 210 comes into close contact with the lower surfaces of the print head portions 36a, 36b, and 36c, the suction chamber Va is the nozzle array K, the suction chamber Vb is the nozzle array C, and the suction chamber Vc is the nozzle array L. _C The _, Suction chamber Vd is nozzle array L _M The suction chamber Ve forms a closed space that covers the nozzle array M, and the suction chamber Vf covers the nozzle array Y. The suction chambers Va to Vf are connected to hoses 220a to 220f, respectively.
[0093]
The pump roller 230c has two small rollers 232 and 234 in the vicinity of the peripheral edge. A hose 220c is wound around these two rollers 232 and 234. When driven by the paper feed motor 31 and the pump roller 230 c rotates in the direction of the arrow, the air in the hose 220 c is pushed by the small rollers 232 and 242, thereby exhausting the closed space in the head cap 210. As a result, ink is sucked from each nozzle of the print head portion 36 and discharged to a waste ink discharge portion (not shown) via the hose 220c. When the ink present at the tip of the nozzle is discharged, new ink is supplied into the nozzle from the relay tank 82 (FIG. 1) side. Thus, for each nozzle array, that is, nozzle array K, nozzle array C, nozzle array nozzle array L _C , Nozzle array L _M The suction can be performed for each of the nozzle array M and the nozzle array Y.
[0094]
=== Cleaning sequence ===
FIG. 14 is a flowchart showing the first embodiment of the operation sequence of the cleaning device according to the present invention. A print mode is designated by the user, a print command signal is input via the host computer 100, a printing operation is executed, and based on a cleaning instruction signal from a printer controller provided in the host computer 100 at predetermined time intervals, After determining whether or not the print head unit 36 is to be cleaned (hereinafter referred to as necessity determination), the print head unit 36 is cleaned as necessary. The necessity determination in this printer is determined based on the designated print mode, the ink color of the nozzle array having the non-operating nozzles, and the number of non-operating nozzles in the ink color, and the threshold value as the determination criterion is shown in FIG. Is set and stored in the database. Here, the threshold is set for the number of non-operating nozzles that are allowed separately for yellow ink and other color inks that have little effect on the image even if missing dots occur, and when printing in the high-speed printing mode. The cleaning sequence will be described. In FIG. 15, there are two types of threshold values TYPE1 and TYPE2, but TYPE2 is set in consideration of the fact that dot omission is less noticeable than high-quality print mode due to high ink discharge density in high-definition print mode. Any type may be selected.
[0095]
When a print command signal is received from the host computer 100, a printing operation is executed, and a time is measured by a timer provided in the host computer 100, and a cleaning instruction signal is transmitted to the printer every time a predetermined time elapses ( S301). When the system controller 54 receives the cleaning instruction signal, ink discharge determination corresponding to the set print mode (S302) is executed by the ink discharge determination unit 41 (S308). When the non-operating nozzle is not detected by the ink ejection determination, the printing operation is continued (S316). When the non-operating nozzle is detected, the system controller 54 counts the non-operating nozzle and the nozzle array having the non-operating nozzle. The ink color is determined (S309). At this time, if the detected non-operating nozzle is a yellow nozzle and the number of non-operating nozzles of the yellow nozzle is three or more, or the detected non-operating nozzle is a nozzle of a color other than the yellow nozzle When the number of non-operating nozzles in any color nozzle array is two or more, the nozzle array having the non-operating nozzles is cleaned (S311 and S313). That is, if the number of non-operating nozzles is two or less for yellow nozzles, and one or less non-operating nozzles are used for nozzles of other colors, the printing operation is continued without cleaning (S316).
[0096]
In the high-quality print mode, the number of non-operating nozzles allowed for yellow nozzles is one, and is not allowed for nozzles other than yellow. In the high-definition printing mode, since it is not allowed to have a non-operating nozzle regardless of the ink color, when a non-operating nozzle is detected by the ink ejection determination unit 41 (S314), the nozzle having the nozzle The array is cleaned (S315).
[0097]
According to this cleaning device, in the high-speed printing mode in which the printing speed is given priority over the image quality, the allowable number of non-operating nozzles is set larger than that in the high-quality printing mode, etc. There is a high possibility that the number of cleanings is reduced. For this reason, waste of time due to cleaning is suppressed, and printing can be performed in a short time.
[0098]
In addition, the allowable number of non-operating nozzles for yellow ink that has a small influence on image quality is set to be larger than the allowable number of non-operating nozzles for other ink colors that have a large influence on image quality. Compared with the case where the necessity of cleaning is determined only by the number of non-operating nozzles, it is possible to print faster while maintaining the required image quality.
[0099]
In the first embodiment, the threshold value for determining whether or not to perform cleaning is the number of non-operating nozzles according to the print mode. However, the threshold value is simply the number of non-operating nozzles according to the ink color and ink density. Good. That is, for yellow ink, light cyan ink, and light magenta ink that do not affect the image even if there are nozzles that do not eject ink, the number of cleaning operations can be reduced by increasing the number of non-operating nozzles. Can be prevented. In addition, when the ink color is set for each nozzle array in which the nozzles are arranged in a row, or when the ink density differs depending on the nozzle array, the number of allowed non-operating nozzles is set in the nozzle array. It may be set every time.
[0100]
<<< Second Embodiment >>
In this embodiment, although ink is ejected from the nozzle, the ink is ejected to a position deviating from the ejection target position when the ink is solidified or adhered to the tip of the nozzle (hereinafter referred to as flying). This is to prevent the nozzle from being erroneously detected as a non-operating nozzle and to clean the nozzle. When the deviation amount of the actual ejection position with respect to the ejection target position is less than the allowable deviation amount, the nozzle is not cleaned. The overall schematic configuration of the present embodiment is substantially the same as the configuration of the first embodiment described above. Therefore, the same members are denoted by the same reference numerals, and only the differences will be described.
[0101]
=== Detection of deviation due to flight bend ===
The detection of the flight bend is performed by the ink discharge determination unit 41 and the detection pulse determination unit 42 which constitute the ink discharge state inspection means. In response to a command from the system controller 54, ink is ejected from the nozzles while moving the carriage 28 on which the print head unit 36 is mounted in the main scanning direction, and the ink blocks the beam of the laser light L from the ink ejection determination unit 41. Similar to the above-described nozzle array detection determination, the detection pulse determination unit 42 compares the time interval of the detection pulses generated by this with a predetermined threshold value.
[0102]
FIG. 16 is an explanatory diagram showing ink ejected into the beam of the laser beam L and a signal waveform for detecting the ink. FIG. 16A shows a signal waveform when ink is ejected to the ejection target position. FIG. 16B shows a signal waveform when a flight curve occurs.
[0103]
When the flight curve as shown in FIG. 16B occurs, the time tm measured by the timer, that is, the time from the falling edge of the detection pulse to the rising edge of the next detection pulse, the ink is discharged at the discharge target position. It becomes longer (shorter) by Δt than the time interval tn in the case of being performed. This time interval Δt indicates the amount of deviation of the actual ejection position from the ejection target position of the ejected ink as time. This deviation amount is converted into a distance based on the scanning speed of the carriage, and is compared with an allowable deviation amount, which will be described later, by the detection pulse determination unit 42. When the amount of deviation becomes larger than the allowable amount of deviation, the print head unit 36 is cleaned.
[0104]
=== Cleaning sequence ===
FIG. 17 is a flowchart showing a second embodiment of the operation sequence of the cleaning device according to the present invention. The necessity of cleaning in this printer is determined on the basis of the designated print mode, the ink color of the nozzle array having nozzles that generate flying skew, and the amount of deviation in a specific ink color. The quantity is set as shown in FIG. 18 and stored in the database. Here, the allowable shift amount is shown as a distance determined to be allowable in order to maintain the image quality required in each print mode. Similarly to the first embodiment, when a missing dot is generated, an allowable shift amount is set separately for yellow ink and other color ink that have little influence on the image, and printing is performed in the high-speed printing mode. The cleaning sequence will be described.
[0105]
A printing command signal is received from the host computer 100 and a printing operation is executed. A cleaning instruction signal is transmitted to the printer every time a predetermined time elapses (S401). When the system controller 54 receives the cleaning instruction signal, the set print mode is specified (S402), and a detection pulse is generated by the ink ejection determination unit 41, and a time interval of the detection pulse and a normal time interval tn are detected. The comparison is made by the pulse determination unit 42, and based on this result, the nozzle array in which the ink flight curve is generated is specified (S409). If a nozzle with a flying curve is not detected by the ink ejection determination, the printing operation is continued (S418), and if detected, the system controller 54 counts the nozzles with a flying curve. At the same time, the ink color of the nozzle array having the nozzle in which the flight curve is generated is determined (S410). At this time, the detected nozzle where the flight curve is generated is a yellow nozzle, and the amount of deviation of the ink ejected from the nozzle where the flight curve of the yellow nozzle is generated is larger than 100 μm or is detected. When the nozzles in which the flying curve is generated are nozzles of a color other than the yellow nozzle, and the deviation amount of the ink ejected from the nozzle in which the flight curve is generated in the nozzle array of any color is larger than 70 μm Then, the nozzle array having the nozzle in which the flight curve is generated is cleaned (S412 and S414). That is, if the displacement amount is 100 μm or less for the yellow nozzle and the displacement amount is 70 μm or less for the nozzles of other colors, the printing operation is continued without cleaning (S418).
[0106]
In the high-quality print mode, the allowable deviation amount with respect to the yellow nozzle is 70 μm or less, and the allowable deviation amount with respect to the nozzles of other colors is 35 μm or less. Further, in the case of the high-definition print mode, when the nozzle that does not allow the flight curve and the flight curve having a deviation larger than 35 μm is detected by the ink discharge determination unit 41, the print curve is detected regardless of the ink color. The nozzle array is cleaned. Here, the reason why the allowable deviation amount is set to 35 μm even in the high-definition printing mode is that the deviation amount between the ejection target position and the actual ejection position, which is generated due to component accuracy, assembly accuracy, or the like, is taken into consideration.
[0107]
According to this cleaning device, even when a flight bend of a level that does not affect the image occurs, the nozzle is not cleaned each time, so that an image of a required image quality level can be output earlier.
[0108]
In the second embodiment, the threshold value for determining whether or not to perform cleaning is the allowable shift amount corresponding to the print mode, but it may be simply the allowable shift amount corresponding to the ink color and ink density. That is, for yellow ink, light cyan ink, and light magenta ink that do not affect the image even if there is a nozzle that does not eject ink, setting a large allowable misalignment reduces the number of cleanings and wastes time. It becomes possible to prevent. In addition, when the ink color is set for each nozzle array in which the nozzles are arranged in a row, or when the ink density varies depending on the nozzle array, the allowable deviation amount is set for each nozzle array. May be.
[0109]
=== Others ===
In the first embodiment and the second embodiment, the example in which the threshold value for determining whether cleaning is necessary is set to one of the number of non-operating nozzles and the amount of deviation due to flight bending. However, the number of non-operating nozzles and flight bending is illustrated. The necessity of cleaning may be determined in combination with the amount of deviation. For example, in the high-speed printing mode, the nozzle inspection unit 40 detects that there are three or more non-operating nozzles in the nozzle array that discharges yellow ink, or the ink discharge determination is performed when the amount of deviation due to flight bending is greater than 100 μm. If it is determined by the unit 41 and the detection pulse determination unit 42, the print head unit 36 may be cleaned, or the flight ejection exceeding the allowable deviation amount is generated by the ink ejection determination unit 41 and the detection pulse determination unit 42. When a nozzle to be detected is detected, the detection pulse determination unit 42 counts up the number of detected nozzles as non-operating nozzles, and a threshold value corresponding to the print mode or ink color may be set. Further, the items used for determining whether or not cleaning is necessary are not limited to the number of non-operating nozzles and the amount of misalignment due to flying bends, but may be the type of print medium. Furthermore, in each nozzle array, since the ease of clogging differs depending on any of the leading nozzle, the trailing nozzle, and the intermediate nozzle located between them, depending on the position of the nozzle in such a nozzle array. A threshold may be set. In addition, since the ink characteristics vary depending on the environment in which the ink is used, it is desirable to set a threshold value according to the environment.
[0110]
The above-described embodiments of the present invention are for facilitating the understanding of the present invention, and do not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.
[0111]
Moreover, although the printing paper has been described as an example of the printing material, a film, a cloth, a thin metal plate, or the like may be used as the printing material.
[0112]
Further, a computer main body, a display device connected to the computer main body, a printer according to the above-described embodiment connected to the computer main body, an input device such as a mouse and a keyboard provided as necessary, a flexible disk drive A computer system having a device and a CD-ROM drive device can also be realized, and the computer system realized in this way is an overall system superior to the conventional system.
[0113]
The printer according to the above-described embodiment may have a part of functions or mechanisms respectively included in the computer main body, the display device, the input device, the flexible disk drive device, and the CD-ROM drive device. For example, the printer includes an image processing unit that performs image processing, a display unit that performs various displays, and a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. Also good.
[0114]
In the above embodiment, an example in which a color inkjet printer is provided with a cleaning device has been described. However, the present invention is not limited to this as long as it is a device that can perform printing processing on a printing medium, and includes, for example, a monochrome inkjet printer, a facsimile, and a reading unit. The present invention may be applied to a copying apparatus provided.
[0115]
【The invention's effect】
According to the present invention, the print time can be shortened by eliminating unnecessary cleaning of the print head corresponding to the required image quality, and the adverse effect on the good nozzles can be suppressed, and the print head can be efficiently cleaned. Cleaning device, inkjet printer equipped with the cleaning device, computer program for causing the cleaning device to clean, computer system, and printing time by eliminating unnecessary cleaning of the print head in response to the required image quality In addition, it is possible to realize a cleaning method for efficiently cleaning the print head while suppressing the occurrence of adverse effects on good nozzles.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a main configuration of a color inkjet printer according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing an overall configuration of a computer system including a color inkjet printer.
FIG. 3 is a block diagram illustrating an electrical configuration of a color inkjet printer.
FIG. 4 is a block diagram illustrating an electrical configuration of a nozzle inspection unit.
FIG. 5 is an explanatory diagram illustrating the configuration of an ink discharge determination unit and the principle of the determination method.
FIG. 6 illustrates an example of a nozzle block that is a determination target for each reciprocating scan of the print head unit.
FIG. 7 is an explanatory diagram showing ink ejected from a nozzle of # 1 into a laser beam and a signal waveform for detecting the ink.
FIG. 8 is an explanatory diagram showing ink ejected from a # 5 nozzle into a laser beam and a signal waveform for detecting the ink.
FIG. 9 is an explanatory diagram showing signal waveforms over a plurality of nozzle arrays.
FIG. 10 is a flowchart showing a process for specifying a nozzle array in which a non-operating nozzle exists.
FIG. 11 is a flowchart showing a process for aggregating the number of determinations.
FIG. 12 is a table showing an example of the total number of determination times.
FIG. 13 is a perspective view showing a nozzle suction mechanism.
FIG. 14 is a flowchart showing a cleaning sequence of the first embodiment.
FIG. 15 is a table illustrating threshold values used in the first embodiment.
FIG. 16 is an explanatory diagram showing signal waveforms for detecting ink when a flight curve occurs.
FIG. 17 is a flowchart showing a cleaning sequence of the second embodiment.
FIG. 18 is a table for explaining an allowable shift amount used in the second embodiment.
[Explanation of symbols]
20 color inkjet printer
22 Paper stacker
24 Paper feed roller
26 Platen version
28 Carriage
30 Carriage motor
32 Timing belt
34 Guide rail
36 Print head
36a First print head
36b Second print head
36c Third print head
40 Nozzle inspection section
41 Ink ejection determination unit
41a Light emitting part
41b Light receiver
42 Detection pulse determination unit
43 Nozzle identification part
46 Waste ink tray
50 Receive buffer memory
52 Image buffer
54 System Controller
56 Main memory
58 timer
61 Main scan driver
62 Sub-scanning driver
64 Inspection unit driver
70 Operation panel
82 Relay tank
82a tube
100 Host computer
200 Nozzle suction mechanism
210 head cap
220a, 220b, 220c, 220d, 220e, 220f hose
230b Pump roller
232, 234 Small roller

Claims (4)

A cleaning apparatus comprising: an ink discharge inspection unit that inspects whether or not a plurality of ink discharge units form an image by discharging ink onto a medium, and cleaning the ink discharge unit;
A threshold value is set according to the operation mode of the ink ejection unit corresponding to the image quality when forming the image,
The ink ejection inspection means inspects the number of non-operating ink ejection portions that do not eject ink,
Determining whether to perform cleaning based on the threshold value and the inspection result of the ink ejection inspection means;
The ink ejection unit is provided as a nozzle array for each ink color corresponding to a plurality of ink colors used for forming the image,
The threshold is set for each ink color based on the number of non-operational ink ejection units allowed according to the operation mode and the ink color,
The cleaning device is a cleaning device that sucks in the suction chamber for each nozzle array,
The cleaning is cleaning performed for each nozzle array with respect to a nozzle array including a non-operating ink discharge portion that does not discharge the ink, and sucks the ink discharge portion.
Cleaning device. The cleaning device according to claim 1,
An allowable deviation amount of the actual ejection position of the ink ejected from the ink ejection section with respect to the ejection target position is set according to the operation mode, and the ink ejection inspection unit ejects the ink ejected from the ink ejection section. A cleaning apparatus, wherein when the deviation amount of the actual ejection position with respect to the target position is larger than the allowable deviation amount, the ink ejection unit is determined as a non-operating ink ejection unit that does not eject ink.   A printing apparatus comprising the cleaning apparatus according to claim 1, wherein the printing apparatus forms an image on a medium by ejecting ink from the plurality of ink ejection sections. A cleaning method using an ink discharge inspection means for inspecting the presence or absence of ink discharge of a plurality of ink discharge portions that form an image by discharging ink onto a medium, and using a cleaning device for cleaning the ink discharge portion,
Setting a threshold value according to the operation mode of the ink ejection unit corresponding to the image quality when forming the image;
A step of inspecting the number of non-operating ink discharge portions that do not discharge ink by the ink discharge inspection means;
Determining whether to clean based on the inspection result and the threshold,
The ink ejection unit is provided as a nozzle array for each ink color corresponding to a plurality of ink colors used for forming the image,
The step of setting the threshold value sets the threshold value for each ink color based on the number of non-operational ink ejection units allowed according to the operation mode and the ink color,
The cleaning device is a cleaning device that sucks in the suction chamber for each nozzle array,
The cleaning is cleaning performed for each nozzle array with respect to a nozzle array including a non-operating ink discharge portion that does not discharge the ink, and sucks the ink discharge portion.
Cleaning method.

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