JP2004299218A - Inkjet printing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent clogging of nozzles by carrying out dummy printing without damaging the design of a printing medium for actual printing at a low cost in relation to an inkjet printing system which carries out printing by discharging ink from corresponding nozzles among a nozzle group of a print head. <P>SOLUTION: A dummy printing sheet 25 to be dummy printed is set on a transfer belt 24 of a printing region transfer means 12 which transfers a sheet of the printing medium to a printing region by an inkjet printing part 16. Dummy printing is carried out by discharging the ink from all of the nozzles of the inkjet printing part 16 onto the dummy printing sheet 25 periodically transferred by the transfer belt 24, and making the ink absorbed into the dummy printing sheet 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inkjet printing system that performs printing by discharging ink from corresponding nozzles of a nozzle group of a print head.
[0002]
[Prior art]
2. Description of the Related Art In recent years, ink jet printers that perform printing by ejecting ink onto a predetermined printing body are roughly classified into a thermal type and a piezo type, which are widely used for personal use and business use. In such an ink jet printer, it is a proposition to prevent clogging of each nozzle that discharges ink for maintaining quality.
[0003]
2. Description of the Related Art Conventionally, many ink jet printers have a configuration in which a print head includes a plurality of orifices for storing ink, and nozzles communicating therewith are arranged. Printing is performed by discharging ink droplets from the orifice from the nozzle tip by the above-described method. However, ink is not always ejected from all the nozzles, and the nozzles that are not used for a long time evaporate the water content of the ink in the nozzle portion and reduce the ejection amount, or solidify to cause clogging. In order to prevent such a situation from occurring, an ink jet printer described in the following patent document is known.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 08-142348
The ink jet printer described in the above patent document is a thermal printer in which a plurality of (for example, four colors) nozzle rows are arranged for multiple colors. It is shown that by performing predetermined printing on the end portion of the recording medium using black ink as the ink, clogging of each ink row is prevented. On the other hand, it is also known that clogging is prevented by ejecting ink from all nozzles to a dummy recording medium before actual printing, not on an actual recording medium as described above.
[0006]
FIG. 8 is an explanatory diagram of dummy ejection of ink by a conventional inkjet printing system. An ink jet printing system 101 shown in FIG. 8A is, for example, a business type, and includes a medium supply / conveyance mechanism 102, a print area conveyance mechanism 103 for performing printing, and a medium discharge / conveyance mechanism 104. You. In the printing area transport mechanism 103, a transport belt 105 having a predetermined number of suction holes formed between a predetermined number of rotating rollers is suspended, and suction fixing means 106 is provided at a printing portion. In addition, an ink jet printing unit 107 and a sensor 108 for detecting the leading edge of the medium are arranged above the printing part.
[0007]
When printing is performed on such a print area transport mechanism 103, as shown in FIG. 8B, a dummy recording medium 111 is transported onto the print area transport mechanism 103 before actual printing, and the sensor 108 By performing dummy printing 112 in which ink is ejected from all the nozzles by the printing unit 107 when the leading edge is detected, clogging of the nozzles corresponding to ink ejection during actual printing is to be prevented.
[0008]
[Problems to be solved by the invention]
However, in the ink jet printer disclosed in the above-mentioned patent document, there is a problem that the design is impaired since the actual printing is performed even though the printing is not conspicuous on the recording medium for the actual printing. In addition, in the inkjet printing system 101 shown in FIG. 8, since the dummy printing 112 is performed on the dummy recording medium 111 for each predetermined number of recording media for the actual printing, there is a problem that the cost is increased accordingly.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an ink jet printing system that performs dummy printing at low cost without impairing the design of a printing medium for real printing and prevents nozzle clogging.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is an ink jet printing system for performing printing by discharging ink on a sheet of print medium supplied by a supply transporting means, An ink jet printing unit comprising a nozzle array and discharging ink from a corresponding nozzle to the printing medium; and the printing medium arranged in an area where printing is performed by the ink jet printing unit and conveyed by the supply conveyance unit And a printing area conveying means provided with a dummy printing unit for discharging ink from all the nozzles of the ink jet printing unit on the conveying belt, and at least the printing The main printing is performed on the medium based on predetermined printing data, and the printing area is transported. Print control processing means for detecting the dummy printing portion periodically conveyed by the conveying belt of a stage and discharging ink from all the nozzles of the ink jet printing portion on the dummy printing portion to perform dummy printing And a configuration having:
[0011]
In the invention according to claims 2 to 4, the “dummy printing portion is a dummy printing sheet formed of a material that absorbs the ink to be ejected”,
`` The dummy printing section is a dummy printing sheet formed of a non-absorbing material for the ejected ink, and includes a cleaning unit for wiping the ink ejected on the dummy printing sheet '',
The configuration is such that, before the dummy print on the dummy print sheet is wiped by the cleaning unit, the dummy print is imaged by the imaging unit, and which nozzle is clogged is determined from the imaged data.
[0012]
As described above, the dummy printing unit that performs dummy printing on the transport belt of the print area transport unit that transports the print medium to the print area by the inkjet printing unit is provided, and the dummy print unit that is periodically transported by the transport belt is provided. Ink is ejected from all the nozzles of the ink jet printing unit to perform dummy printing. In other words, the provision of the dummy printing portion on the transport belt allows dummy printing to be performed without impairing the design of the printing medium for the main printing, and the printing medium for the dummy printing is not required unlike the related art. This makes it possible to prevent nozzle clogging at a low cost.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The term "printing" used in the description of the inkjet printing system of the present invention means not only printing of characters but also printing of images and the like, and includes the concept of printing.
[0014]
FIG. 1 shows a configuration diagram of an inkjet printing system according to the first embodiment of the present invention. FIG. 1A is a configuration diagram of a main part of an ink jet printing system, and FIG. 1B is a conceptual explanatory diagram of a printing area conveying unit. 1A and 1B, an inkjet printing system 11 includes a print area transport mechanism 12 for performing printing, and a medium supply transport mechanism that transports a print medium from a supply source at a preceding stage and a subsequent stage thereof. 13 and a medium discharging / conveying mechanism 14 for discharging a printed medium on which printing has been performed to a predetermined stacker are arranged to constitute a main part of the system.
[0015]
Further, the print area transport means 12 is provided with a suction fixing means 15 for reliably transporting the belt while sucking and fixing the print medium by air or the like. Above a predetermined position of the printing area conveying means 12, an ink jet printing section 16 and a leading end detecting means 17 are arranged. Further, a sheet detecting unit 18 is provided at a position in the vicinity of a conveying belt of the printing area conveying unit 12 which will be described later and before the conveying belt is exposed on the medium supply / conveying unit 13 side. The medium supply / conveyance means 13 is driven and controlled by the conveyance drive means 19.
[0016]
In the print area transport mechanism 12, for example, a transport belt 24 is suspended between three belt rollers 21 to 23. The transport belt 24 has a predetermined number of suction holes 24A for suction-fixing a print medium. ing. A dummy print sheet 25 which is a predetermined position of the transport belt 24 and covers the width direction of the print medium (perpendicular to the transport direction) and is a dummy print portion is provided. An object to be detected 26 is provided at one end.
[0017]
The dummy print sheet 25 is for ejecting ink from all the nozzles of the ink jet printing unit 16, and is made of a material that sucks the ejected ink, for example, a highly absorbent polymer. Further, the detection target 26 can be realized by, for example, forming a magnetic substance (or metal) and configuring the sheet detecting means 18 with a magnetic sensor (or metal detection sensor).
[0018]
The suction fixing means 15 is disposed below an upper linear portion of the printing area conveying means 12 which is a printing area on the conveyor belt 24, and the ink jet printing section 16 and the tip are provided above the printing area part. The detecting means 17 is provided.
[0019]
In the medium supply / conveyance means 13, a conveyance belt 32 is suspended between two belt rollers 31 (one is omitted), and conveys a print medium from the supply source onto the print area conveyance means 12. The medium discharge / conveyance means 14 has a conveyance belt 32 suspended between two belt rollers 41 (one of which is omitted), discharges the print medium from the print area conveyance means 12, and conveys the print medium to a predetermined stacker. The ink jet printing unit 16 includes a predetermined number of nozzle rows and discharges ink from a corresponding nozzle to a print medium, and has the same configuration as that of the conventional ink jet printing. The leading edge detecting means 17 is for detecting the leading edge of the dummy print sheet 25 and the supplied print medium to measure the timing of printing by the ink jet printing unit 16. used.
[0020]
Here, FIG. 2 shows a control block diagram of ink ejection by the inkjet printing system of FIG. FIG. 2 shows that at least the actual printing is performed on the print medium based on predetermined print data, and the dummy print sheet 25 periodically conveyed by the conveyance belt 24 is detected by the sheet detecting means 18 so that the dummy print sheet 25 is detected. Print control processing means 51 for ejecting ink from all the nozzles of the ink jet printing unit 16 on the print sheet 18 to perform dummy printing is shown. The control means 52, bus 53, interface (IF) 54 , Transport control means 55, print control means 56, and print data file creation means 57.
[0021]
The control means 52 supervises the drive control of this system, and stores a program for that. The IF 54 matches the detection signal input from the leading edge detection unit 17 and the sheet detection unit 18 and matches the drive control signal output to the ink jet printing unit 16 and the transport driving unit 29. The transport control means 55 generates a drive control signal for causing the transport drive means 19 to transport the print medium onto the print area transport means 12 from the supply transport means 13 according to the detection signal from the sheet detection means 18. And send it out. That is, this is for controlling the supply of the print medium so that the print medium supplied to the dummy print sheet 25 provided on the transport belt 24 is not overlapped.
[0022]
The print control means 56 generates and sends a drive control signal for discharging ink from a predetermined nozzle to the ink jet printing unit 16 in accordance with a detection signal from the leading end detection means 17. These are drive control signals for controlling ink ejection from the corresponding nozzles at the time of actual printing based on the print data file, and controlling ink ejection for all nozzles at the time of dummy printing based on the print data file described later. The print data file creating means 57 creates a print data file for the actual print based on the print information input for the actual print, and also prints a print data file for the dummy print (optionally). , Print data for ejecting ink from all nozzles).
[0023]
The print control processing unit 51 performs drive control on the print area transport unit 12, the medium discharge transport unit 14, the suction fixing unit 15, and a drive control unit for a mechanism (not shown). The transport speed of the print area transport unit 12 and the transport speed of the medium discharge transport unit 14 are predetermined and driven.
[0024]
Therefore, FIG. 3 shows a flowchart of the ink ejection process in FIG. 2, and FIGS. 4 and 5 show operation explanatory diagrams of the ink ejection in FIGS. 1 and 2. In FIG. 3, first, the print area conveying unit 12 is driven by a not-shown conveying driving unit, and the conveying belt 24 rotates between the belt rollers 21 to 23. Therefore, when the sheet detection unit 18 detects the detection target 26 of the dummy print sheet 25 provided on the transport belt 24, the detection signal is input (step (S1), FIG. 4A). ).
[0025]
In response to the detection signal from the sheet detecting means 18, the conveyance control means 55 sends a drive control signal to the conveyance driving means 19 after a predetermined time, and causes the medium supply / conveyance means 13 to supply the print medium 61 onto the print area conveyance means 12. (S2). That is, when the print medium 61 is supplied from the medium supply / conveyance means 13, the control is performed so that the print medium 61 supplied to the dummy print sheet 25 provided on the conveyance belt 24 does not overlap (FIG. 4B )).
[0026]
Subsequently, when a detection signal at the time when the leading edge detecting means 17 first detects the leading edge from the detection of the dummy print sheet 25 by the sheet detecting means 18 is input (S3), the printing control means 56 determines a predetermined value based on the leading edge detection. After a lapse of time, based on the print data file created by the print data file creating means 57, a print drive control signal for ejecting ink from all nozzles is generated and sent to the inkjet printing section 16 (S4). Here, the ink jet printing unit 16 performs the dummy printing 62 on the dummy printing sheet 25 (FIG. 5A).
[0027]
Then, when the leading edge detecting means 17 receives a detection signal when the leading edge is detected for the second time after the detection of the dummy print sheet 25 by the sheet detecting means 18 (S5), the printing control means 56 determines a predetermined value based on the leading edge detection. After a lapse of time, a print drive control signal for discharging ink from the corresponding nozzle is generated and transmitted to the inkjet printing unit 16 based on the print data file for the print medium 61 created by the print data file creation means 57. (S6). Here, the ink jet printing unit 16 performs actual printing on the printing medium 61 (FIG. 5B). Steps S1 to S6 are repeated for each print medium 61 to be printed (or for each predetermined number of sheets), and the process ends when the actual printing is performed on all the number of print media 61 (S7).
[0028]
As described above, since the dummy print sheet 25 is provided on the conveyor belt 24, the dummy print 62 can be performed without deteriorating the design of the print medium 61 for the main print. Since no medium is required, nozzle clogging can be prevented at low cost.
[0029]
Next, FIG. 6 shows a configuration diagram of an inkjet printing system according to a second embodiment of the present invention. FIG. 6A is a schematic view of a main part of the present system, and FIG. 6B is an explanatory view of a cleaning unit. The basic configuration of the ink-jet printing system 11 in FIG. 6A is the same as that in FIG. 1 and the description is omitted. However, in this system, instead of the dummy print sheet 25 formed of the ink absorbing material, This is a dummy print sheet 25A formed of a material to be absorbed (for example, plastic or metal).
[0030]
Further, a cleaning means 71 is disposed at a rear stage (rear side in the transport direction) of the ink jet printing unit 16 so as to be vertically movable (a driving means is not shown), and a sheet detecting means 72 is disposed at a front stage of the cleaning means 71. It is. The cleaning means 71 is for wiping ink ejected onto the dummy print sheet 25A, and for example, a highly absorbent polymer is used. The sheet detecting means 72 is the same as the sheet detecting means 18 and is for detecting the object 26 to be detected. When the dummy print sheet 25A is formed of metal, the sheet detection means 18 and 72 can be formed of a metal detection sensor, and the detection target 26 can be omitted.
[0031]
That is, after the ink is ejected onto the dummy print sheet 25A by the ink jet printing unit 16 and dummy printing is performed, when the sheet detection unit 72 detects the dummy print sheet 25A with the detection target 26, FIG. As shown in (2), the cleaning means 71 descends and contacts the dummy print sheet 25A. As a result, the ink of the dummy print 62 is wiped off by the cleaning means 71 and can be used for the next dummy print.
[0032]
As a result, since dummy printing can be performed on the dummy print sheet 25A as needed, nozzle clogging can be prevented at a low cost without damaging the design of the print medium for actual printing, as described above.
[0033]
Next, FIG. 7 shows a configuration diagram of an inkjet printing system according to another embodiment of the second embodiment of the present invention. FIG. 7A is a schematic diagram of a main part of the present system, and FIG. 7B is an explanatory diagram of an imaging unit. The basic configuration of the inkjet printing system 11 in FIG. 7A is the same as that in FIG. 6 and the description is omitted. In this system, an imaging unit 73 is provided in front of the cleaning unit 71 (in front of the transport direction). It is.
[0034]
The imaging means 73 is for imaging the dummy print 62 by the imaging means 73 before the cleaning means 71 wipes the dummy print 62 on the dummy print sheet 25A. The image data picked up by the image pickup means 73 is sent to the print control processing means 51. In the print control processing means 51, although not particularly shown, the image data processing means and the discrimination means are not shown. Based on this, it is determined which nozzle of the ink jet printing unit 16 is clogged.
[0035]
Thereby, for example, when any nozzle is clogged, the system drive is stopped by recognizing the clogging, and after performing maintenance of the nozzle where the clogging of the inkjet printing unit 16 is specified, Printing can be performed and printing quality can be maintained.
[0036]
【The invention's effect】
As described above, according to the present invention, a dummy printing unit for performing dummy printing on a transport belt of a print area transport unit that transports a print medium to a print area by an inkjet printing unit is provided, and a transport belt of the print area transport unit is provided. By discharging ink from all the nozzles of the ink jet printing unit and performing dummy printing on the dummy printing unit that is provided and conveyed periodically, at low cost, the design of the print medium of this printing is not spoiled. Nozzle clogging can be prevented.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an inkjet printing system according to a first embodiment of the present invention.
FIG. 2 is a control block diagram of ink ejection by the inkjet printing system of FIG. 1;
FIG. 3 is a flowchart of the ink ejection process of FIG. 2;
4 is an explanatory diagram (1) of an ink ejection operation according to FIGS. 1 and 2. FIG.
FIG. 5 is an explanatory diagram (2) of an ink ejection operation according to FIGS. 1 and 2;
FIG. 6 is a configuration diagram of an inkjet printing system according to a second embodiment of the present invention.
FIG. 7 is a configuration diagram of an inkjet printing system according to another embodiment of the second embodiment of the present invention.
FIG. 8 is an explanatory diagram of dummy ejection of ink by a conventional inkjet printing system.
[Explanation of symbols]
REFERENCE SIGNS LIST 11 inkjet printing system 12 print area transport mechanism 13 medium supply transport mechanism 14 medium discharge transport mechanism 15 suction fixing means 16 inkjet printing unit 17 leading edge detection means 18, 72 sheet detection means 19 transport drive means 24, 32, 42 transport belt 25 dummy Print sheet 26 Detected object 51 Print control processing means 61 Print medium 62 Dummy print 71 Cleaning means 73 Imaging means

Claims (4)

An ink jet printing system for discharging ink to perform printing on a sheet of print medium supplied by a supply transport unit,
An inkjet printing unit that includes a predetermined number of nozzle rows and discharges ink from the corresponding nozzles to the print medium,
It is arranged in an area where printing is performed by the inkjet printing unit, and transports the printing medium transported by the supply transport unit to the inkjet printing unit by a transport belt. A print area transport unit provided with a dummy print unit for ejecting ink from all nozzles,
At least, the main printing is performed on the printing medium based on predetermined printing data, and the dummy printing section periodically conveyed by the conveyance belt of the printing area conveyance means is detected and the dummy printing section is detected. Print control processing means for performing dummy printing by discharging ink from all nozzles of the inkjet printing unit,
An inkjet printing system, comprising: 2. The ink-jet printing system according to claim 1, wherein the dummy printing section is a dummy printing sheet formed of a material that absorbs the ejected ink. 2. The ink jet printing system according to claim 1, wherein the dummy printing unit is a dummy printing sheet formed of a non-absorbing material for the ink to be discharged, and the ink discharged on the dummy printing sheet is An ink-jet printing system comprising a wiping unit. 4. The ink-jet printing system according to claim 3, wherein the dummy print is imaged by an image pickup means before the dummy print on the dummy print sheet is wiped by the cleaning means, and which nozzle is clogged from the image pickup data. An ink-jet printing system characterized in that the printing is determined.

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