JP7336837B2 - Printer inspection method and printer - Google Patents

Description

The present invention relates to a printer inspection technique for inspecting printer characteristics.

Some printers are equipped with a function for correcting errors in the amount of ink ejected from each head and errors in the amount of ink ejected due to continuous use. These errors can be measured by examining the color densities of the patches printed by the printer. As a method for performing such an inspection, there is a technique disclosed in Patent Document 1.

The inspection method disclosed in Patent Literature 1 includes a patch printing process of printing patches on a medium, and a patch measuring process of scanning the medium with a patch measurement sensor to measure the patches.

When performing the patch measurement process, a pressing plate is placed on the medium to prevent the medium from floating. The pressing plate has an opening corresponding to the patch. A patch measurement sensor inspects the patch facing the aperture.

By pressing the media with the pressing plate, the distance between the media and the patch measurement sensor can be kept constant. As a result, the density of the color of the patch can be accurately detected, and the reliability of the inspection result can be improved.

JP 2017-122688 A

A printer that can use the inspection method disclosed in Japanese Patent Laid-Open No. 2002-300319 has a higher parts cost due to the mounting of the presser plate.

An object of the present invention is to provide an inspection method that can be used even with an inexpensive printer.

According to the present invention, a media placing step of placing the media on the bed of the printer;
a patch printing step of printing patches on the medium;
a patch measurement step of scanning a patch measurement sensor over the medium on which the patch is printed to measure the color density of the patch, the method comprising:
The patch measurement step is performed in a state in which the patch is placed above a suction hole provided in the bed and the medium is pressed against the bed by sucking the medium ,
A printer inspection method is provided , wherein in the patch measurement step, the patch measurement sensor measures the patch directly above the suction hole .

In the present invention, the patch measurement process is performed while the media is pressed against the bed by suctioning the media. The media is held down by using a suction hole through which air is drawn to hold down the media during printing. In other words, the suction holes used during printing are also used during inspection. This eliminates the need for additional parts in the printer for inspection. It is possible to provide a printer inspection method that can be used even with an inexpensive printer.

Alternatively, according to the present invention, a bed provided with a plurality of suction holes for sucking air and capable of fixing media arranged on the upper surface by sucking air from the suction holes;
an ink head capable of printing a patch at a position corresponding to the suction hole in the medium arranged on the bed;
a patch measurement sensor positioned above the bed for measuring the color density of the patch printed on the media ;
The patch measurement sensor can scan above the suction holes and can measure the color density of the patch printed on the medium just above the suction holes. A printer is provided.

In the present invention, the printer has a bed on which the media can be fixed and a patch measurement sensor for measuring the density of the patches. Therefore, by sucking the medium, the patch measurement process can be performed while the medium is pressed against the bed. The media is held down by using a suction hole through which air is drawn to hold down the media during printing. In other words, the suction holes used during printing are also used during inspection. This eliminates the need for additional parts in the printer for inspection. It is possible to provide an inexpensive printer that is capable of performing inspection.

1 is a plan view schematically showing a printer according to an embodiment of the invention; FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1; FIG. FIG. 2 is a diagram for explaining a printer inspection method using the printer shown in FIG. 1; 4 is a cross-sectional view taken along line 4-4 of FIG. 3; FIG.

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the description, left and right refer to left and right with reference to the drawing, and front and back refer to front and rear with respect to the feeding direction of the medium. In the figure, Fr indicates front, Rr indicates rear, Le indicates left, Ri indicates right, Up indicates upper, and Dn indicates lower.
<Example>

Please refer to FIG. The printer 10 is an inkjet printer capable of forming a color image on the medium Me. The printer 10 can print large signboards and posters, for example.

[Configuration of Printer 10]
The printer 10 has a transport device 12 capable of transporting the medium Me, a bed 20 on which the medium Me sent from the transport device 12 can be placed, and rails 14 extending in the width direction above the bed 20. Four ink cartridges 15 filled with colored inks, ink tubes 16 connected to the ink cartridges 15 so as to allow the ink to flow, and ink tubes 16 connected to the ink tubes 16 and running on the rails 14. A movable ink head 30, an inspection device 40 that is fixed to the ink head 30 and inspects the color density of the printed patch, and a media edge detector 60 that detects the left and right ends of the medium Me. , and a control unit 50 for performing a printing operation and controlling the ink head 30 and the like.

The printer 10 prints on the medium Me passing below the ink head 30 while feeding the medium Me forward by the conveying device 12 .

Note that the printer 10 can be equipped with any device such as a cutter device for cutting the medium Me.

[About Media Me]
The medium Me is, for example, a roll medium wound on a roll, and the material of the medium may be paper such as plain paper, resin such as polyvinyl chloride or polyester, or aluminum. It may be made of various materials such as metals, iron materials, and the like. The medium Me is sent from the rear to the front by the conveying device 12 .

[Configuration of bed 20]
Also refer to FIG. The bed 20 has a bed body 21 with a large number of suction holes 21a and a pump 22 connected to the bed body 21 for drawing air from the suction holes 21a.

The bed 20 may employ a fan instead of the pump 22 as long as it can draw air from the suction hole 21a.

[Regarding the ink cartridge 15]
Please refer to FIG. The ink cartridge 15 includes a cyan cartridge 15C filled with cyan ink, a magenta cartridge 15M filled with magenta ink, a yellow cartridge 15Y filled with yellow ink, and a black cartridge 15K filled with black ink. Become.

The number and color of the cartridges constituting the ink cartridge 15 can be arbitrarily selected. The ink to be filled in the ink cartridge 15 is preferably water-based resin ink, which has excellent fixability to media. In order to print a lot in a short time, it is also preferable to select an ink that dries quickly. In addition, any water-based ink or organic solvent-based ink can be selected.

[Regarding the ink head 30]
The ink head 30 includes an ink head main body 31 which is movable on the rail 13, and heads 32C and 32M which are provided in the ink head main body 31 and can eject ink corresponding to the cartridges 15C, 15M, 15Y and 15K, respectively. , 32Y, 32K.

The heads 32C, 32M, 32Y, and 32K include a cyan head 32C that ejects cyan ink, a magenta head 32M that ejects magenta ink, a yellow head 32Y that ejects yellow ink, and a black head 32Y that ejects black ink. and a head 32K.

[Configuration of inspection device 40]
Please refer to FIG. The inspection device 40 is fixed to the side wall of the ink head main body 31 . The inspection apparatus 40 includes an inspection apparatus main body 41, a substrate 42 placed on the inspection apparatus main body 41, a light source 43 mounted on the substrate 42 capable of emitting light, a patch measurement sensor 44 capable of measuring color density, and an inspection apparatus. and a lid body 45 that covers the main body 41 and sandwiches the substrate 42 together with the inspection device main body 41 .

[Configuration of Inspection Apparatus Main Body 41]
The inspection apparatus main body 41 includes a light source hole 41a opened obliquely downward and facing the light source 43, a sensor hole 41b opened substantially vertically and facing the patch measurement sensor 44, and a reflecting portion 41 c that is provided on the inner circumference of the light source hole portion 41 a and reflects the light from the light source 43 .

When the sensor hole 41b is located above the suction hole 21a, the extension line L1 passing through the center of the light source hole 41a is different from the extension line L2 passing through the center of the sensor hole 41b. They intersect at the upper ends of the openings 41b.

For the substrate 42, a printed substrate made of glass can be used that can switch the blinking of the light source 43 and receive the information detected by the patch measurement sensor 44. FIG.

For the light source 43, for example, an LED lamp that emits white light can be used. A material other than the LED can be used for the light source 43 as long as it can illuminate the bed 20 . Moreover, the color of the light source 43 can also employ colors other than white.

A photodiode, a CCD image sensor, a CMOS image sensor, or the like is adopted as the patch measurement sensor 44, for example. Note that the patch measurement sensor 44 is not limited to the above, and any sensor can be employed as long as it can detect the color density of the patches printed on the medium Me.

[Regarding the media edge detector 60]
The media edge detector 60 includes a media detection sensor 61 fixed to the ink head main body 31 and capable of detecting the medium Me, a reflector 62 provided on the upper surface of the bed main body 21 facing the media detection sensor 61, and a position detection sensor 63 provided in the ink head main body 31 for detecting the position of the media detection sensor 61 .

The media detection sensor 61 employs, for example, an optical sensor having a light source and a sensor unit capable of detecting light emitted and reflected by the light source. The media detection sensor 61 is provided so as to be movable left and right together with the ink head main body 31 .

Note that the media detection sensor 61 may be fixed to the inspection apparatus main body 41 . By fixing the media detection sensor 61 to the inspection device main body 41, the media detection sensor 61 can be attached to an existing printer together with the inspection device 40 later.

The reflecting part 62 is composed of, for example, a silver tape attached to the upper surface of the bed body 21 . The reflectors 62 are provided across the left and right ends of the bed body 21 .

A rotary encoder, for example, is employed as the position detection sensor 63 . Since the media detection sensor 61 is fixed to the ink head main body 31 , a rotary encoder for detecting the position of the ink head 30 can be used as the position detection sensor 63 .

[Regarding the control unit 50]
The control unit 50 has a processing unit 51 , a storage unit 52 and a communication unit 53 . The processing unit 51, the storage unit 52, and the communication unit 53 are configured by, for example, microcomputers or microcontrollers. The processing unit 51, storage unit 52, and communication unit 53 can include, for example, a CPU (or MPU or MCU), ROM, RAM, and an input/output interface. For example, the ROM can store programs that cause the CPU to perform predetermined operations. The RAM can form the work area of the CPU. Note that the processing unit 51, the storage unit 52, and the communication unit 53 may be configured by ASIC, FPGA, or the like.

The control unit 50 further has an operation panel 54 as an operation unit that can be operated by the user. The operation panel 54 has operation buttons such as a power button and a setting button, operation switches, and the like.

The storage unit 52 stores position information (encoder coordinates in the movement direction of the heads 32C, 32M, 32Y, and 32K) of the suction holes 21a in advance.

In the printer 10 configured as described above, a difference in ink ejection amount inevitably occurs between the heads 32C, 32M, 32Y, and 32K. Also, the amount of ink ejected from the heads 32C, 32M, 32Y, and 32K may vary depending on the operating environment such as changes in the ambient temperature. Therefore, it is necessary to measure these differences and make corrections based on the measured differences. A test to measure the difference can be performed, for example, immediately after powering on the printer 10 . A detailed description will be given below.

[Media placement process Media measurement process]
Please refer to FIG. First, the conveying device 12 is operated to advance the medium Me. Thus, the medium Me is placed on the bed 20 (media placement step).

[Media measurement process]
Next, the width W1 of the medium Me placed on the bed 20 is measured (medium measurement step). The measurement is performed by the media edge detector 60 . For example, the control unit 50 moves the ink head main body 31 from above the right end P1 of the bed main body 21 to above the left end P2. The media detection sensor 61 fixed to the ink head main body 31 moves together with the ink head 31 from above the right end P1 to above the left end P2.

The media detection sensor 61 detects light reflected by the reflector 62 . On the other hand, the reflector 62 is not detected at the site P3 where the reflector 62 is covered with the medium Me. Therefore, when the media detection sensor 61 is positioned at the right end P1 where the media Me is not arranged, the media detection sensor 61 detects the reflector 62 . When the media detection sensor 61 is moved leftward from this state, the media detection sensor 61 moves above the media Me and stops detecting the reflecting portion 62 . When the media detection sensor 61 is further moved to the left end P2, the media detection sensor 61 detects the reflecting portion 62. As shown in FIG. Whether or not the reflector 62 is detected is sent to the controller 50 as an electrical signal.

The position of the media detection sensor 61 is detected by the position detection sensor 63 and sent to the control unit 50 as an electric signal. can be detected. As a result, the width W1 of the medium Me is detected by detecting the length of the portion where the reflecting portion 62 is not detected.

[Patch printing process]
Next, patches PaC, PaM, PaY, and PaK are printed on the medium Me (patch printing process). Here, a patch is printed on the medium Me, includes a detected portion that is detected by the patch measurement sensor 44, and occupies a wider area than the area detectable by the patch measurement sensor 44 (field of view of the patch measurement sensor 44). It is a figure. At least the area sensed by the patch measurement sensor 44 is entirely composed of the same color and the same density.

When the patch measurement sensor 44 detects a patch, only the patches PaC, PaM, PaY, and PaK exist in the area detectable by the patch measurement sensor 44, and the colors and densities of the patches PaC, PaM, PaY, and PaK are Detected and measured, the color of the surface of the medium Me is not measured. The reason why the areas detected by the patch measurement sensor 44 have the same color and the same density is to accurately measure the colors and densities of the patches PaC, PaM, PaY, and PaK.

The patches PaC, PaM, PaY, and PaK are generally square or rectangular in shape, but may be printed in any shape such as a circle. However, since the shape of the sensing portion of the CCD image sensor or CMOS image sensor that constitutes the patch measurement sensor 44 is generally square or rectangular, it is preferable that the shape of the patch also be similar. This is because by reducing the areas that are not detected by the patch measurement sensor 44, it is possible to reduce waste of the ink and media Me required for printing the patches PaC, PaM, PaY, and PaK. Furthermore, if the patches PaC, PaM, PaY, and PaK are square or rectangular, they can be arranged densely by aligning the patches PaC, PaM, PaY, and PaK vertically and horizontally on the medium Me. The moving distance is shortened when patches PaC, PaM, PaY, and PaK are continuously measured, and an effect that the measurement can be performed in a short time is also obtained.

Patches PaC, PaM, PaY, and PaK correspond to colors of ink ejected from heads 32C, 32M, 32Y, and 32K, respectively. That is, patch PaC is a patch printed by ejecting cyan ink, patch PaM is a patch printed by ejecting magenta ink, and patch PaY is a patch printed by ejecting yellow ink. A patch PaK is a patch printed by ejecting black ink.

After the patch PaK ejected with black ink is printed, the medium Me is transported forward, and then the patch PaY ejected with yellow ink is printed. Similarly, a patch PaM ejected with magenta ink and a patch PaC ejected cyan ink are printed in this order.

Each of the patches PaC, PaM, PaY, and PaK is printed at a plurality of locations (for example, 10 locations) in the width direction. Patches PaC, PaM, PaY, and PaK of the same color are printed in the width direction. The multiple printed patches PaC, PaM, PaY, and PaK of the same color have different densities.

The patches PaC, PaM, PaY, and PaK are printed with the same length W2 spaced from both the left and right ends (both ends in the width direction) of the medium Me. That is, the patch printing process is performed while leaving the gap W2 of the same length at both ends of the medium Me.

Additionally, the patches PaC, PaM, PaY, and PaK are printed at positions corresponding to the positions of the suction holes 21a. The patches PaC, PaM, PaY, and PaK are not printed at the positions corresponding to the suction holes 21a at both ends by printing with a gap W2 at each end. That is, when the direction (width direction) perpendicular to the conveying direction of the medium Me is taken as a reference, the patches PaC, PaM, PaY, and PaK avoid positions corresponding to the suction holes 21a at both ends, and are printed in correspondence with the suction holes 21a of .

[Patch placement process]
Next, the patches PaC, PaM, PaY, and PaK are arranged above the suction holes 21a provided in the bed 20 (patch arrangement step). It should be noted that, as shown in the figure, the patch PaC ejected with cyan ink is printed above the suction hole 21a. In this case, when the patch printing process ends, the patch placement process also ends. That is, in the patch printing process, it is preferable to print the patch PaC (patch) ejected with cyan ink above the suction hole 21a.

[Media holding process]
Next, the medium Me is pressed against the bed 20 by sucking the medium Me with the patch PaC having the cyan ink ejected disposed above the suction hole 21a (media holding step). By operating the pump 22, air is drawn from the suction hole 21a. The medium Me is pressed against the upper surface of the bed 20 by negative pressure.

[Patch measurement process]
Also refer to FIG. Next, the patch measurement sensor 44 is caused to scan the medium Me pressed by the bed 20 to measure the patch PaC on which the cyan ink is ejected (patch measurement step).

At the time of measurement, the density (wavelength) is measured by the patch measurement sensor 44 while the light source 43 is turned on to irradiate the patch PaC onto which the cyan ink is ejected. Information detected by the patch measurement sensor 44 is sent to the control unit 50, and correction is performed based on the sent information.

In the patch measurement process, the patch measurement sensor 44 measures the patch PaC on which the cyan ink is ejected above the suction hole 21a.

[Measurement of other patches]
After the measurement of the patch PaC on which the cyan ink is ejected, the transport device 12 retracts the medium Me. A patch PaM ejected with magenta ink is arranged above the suction holes 21a provided in the bed 20 (patch arrangement step), the medium Me is pressed against the bed 20 (medium pressing step), and the patch PaM ejected with magenta ink is measured. (patch measurement step). Similarly, the patch arrangement process, the media pressing process, and the patch measurement process are performed for the patch PaY ejected with yellow ink and the patch PaK ejected black ink.

Note that the patch printing process for the next patch PaM may be performed after the measurement of the patch PaC in which the cyan ink is ejected is completed. In this case, after the measurement of the patch PaC ejected with cyan ink, the transport device 12 transports the medium Me forward and prints the patch PaM ejected with magenta ink (patch printing step). Repeat this.

In addition, the suction of the medium Me can be appropriately performed not only during the patch measurement process, but also during the patch printing process or the like. Furthermore, the force for sucking the medium Me, that is, the force for pressing the medium Me against the bed 20 can also be adjusted as appropriate.

The print positions and measurement positions of patches PaC, PaM, PaY, and PaK are specified based on the position information stored in storage unit 52 .

The present invention described above has the following effects.

Please refer to FIG. The patch measurement process is performed while the medium Me is pressed against the bed 20 by sucking the medium Me. The medium Me is held down by utilizing the suction holes 21a through which air is drawn to hold down the medium Me during printing. In other words, the suction holes 21a used during printing are also used during inspection. Therefore, no additional parts are required for the printer 10 for inspection. A printer inspection method that can be used even with an inexpensive printer 10 can be provided.

The patch measurement process is performed while the patches PaC, PaM, PaY, and PaK are arranged above the suction holes 21 a provided in the bed 20 . As a result, it is possible to suppress the floating of the patch Pa in particular among the media Me. This makes it possible to obtain more accurate inspection results.

In the measurement process, patch measurement sensor 44 measures patches PaC, PaM, PaY, and PaK above suction hole 21a. More accurate measurement results can be obtained by detecting the patches PaC, PaM, PaY, and PaK from above the suction holes 21a whose floating is suppressed.

Prior to the printing process, there is a media measurement process for measuring the width of the medium Me placed on the bed 20 . The patches PaC, PaM, PaY, and PaK can be printed while avoiding the edges of the medium Me that tend to float. This makes it possible to obtain more accurate measurement results.

The patch printing process is performed with a gap of the same length W2 left at both ends of the medium Me with reference to the direction perpendicular to the transport direction of the medium Me (with the operation direction of the patch measurement sensor 44 as a reference). By printing the patches PaC, PaM, PaY, and PaK more centrally on the medium Me, it is possible to further suppress the floating of the medium Me. This makes it possible to obtain more accurate measurement results.

The printer 10 has a bed 20 on which the medium Me can be fixed, and patch measurement sensors 44 for measuring the densities of the patches PaC, PaM, PaY and PaK. Therefore, the patch measurement process can be performed while the medium Me is pressed against the bed 20 by sucking the medium Me. The medium Me is held down by utilizing the suction holes 21a through which air is drawn to hold down the medium Me during printing. In other words, the suction holes 21a used during printing are also used during inspection. Therefore, no additional parts are required for the printer 10 for inspection. It is possible to provide an inexpensive printer 10 that is capable of performing inspection.

In addition, the ink head 30 can print patches PaC, PaM, PaY, and PaK at positions corresponding to the suction holes 21a. Thereby, the patch measurement process can be performed with the patches PaC, PaM, PaY, and PaK arranged above the suction holes 21 a provided in the bed 20 . As a result, it is possible to suppress the floating of the patch Pa in particular among the media Me. This makes it possible to obtain more accurate inspection results.

The patch measurement sensor 44 can scan over the suction hole 21a. The patches PaC, PaM, PaY, and PaK can be detected from above the suction holes 21a whose floating is suppressed, and more accurate measurement results can be obtained.

It further has a media edge detector for measuring the width of the media Me. The width of the medium Me placed on the bed 20 can be measured prior to the printing process. The patches PaC, PaM, PaY, and PaK can be printed while avoiding the edges of the medium Me that tend to float. This makes it possible to obtain more accurate measurement results.

A patch measurement sensor 44 is fixed to the ink head 30 . A mechanism for scanning the patch measurement sensor 44 can be shared with the ink head 30 . An increase in the number of parts can be suppressed, and the printer 10 can be manufactured at low cost.

Note that the printer inspection method according to the present invention can be performed at a timing other than immediately after the power is turned on. It is also possible to arbitrarily set whether the inspection is to be performed automatically at regular intervals or by the operation of the operator.

The patch printing process does not necessarily leave the same length of air gap on both ends of the media. It can be arbitrarily set according to the width of the medium, the size of the patch, and the number of patches.

As long as the action and effects of the present invention are exhibited, the present invention is not limited to the examples.

The printer inspection method of the present invention is suitable for inkjet printers.

DESCRIPTION OF SYMBOLS 10... Printer 12... Conveying apparatus 20... Bed 21a... Suction hole 30... Ink head 44... Patch measurement sensor PaC, PaM, PaY, PaK... Patch

Claims (5)

a media placement step of placing the media on the bed of the printer;
a patch printing step of printing patches on the medium;
a patch measurement step of scanning a patch measurement sensor over the medium on which the patch is printed to measure the color density of the patch, the method comprising:
The patch measurement step is performed in a state in which the patch is placed above a suction hole provided in the bed and the medium is pressed against the bed by sucking the medium,
In the patch printing step, a gap is left at the edge of the medium with reference to the scanning direction of the patch measurement sensor, and the patch is printed above the suction hole avoiding the suction hole located at the position corresponding to the gap. A method of inspecting a printer, characterized by: 2. The printer inspection method according to claim 1, wherein in said patch printing step, at least a plurality of patches of the same color and different densities are printed. a bed provided with a plurality of suction holes for sucking air, and capable of fixing media arranged on the upper surface by sucking air from the suction holes;
an ink head capable of printing a patch at a position corresponding to the suction hole in the medium arranged on the bed;
a patch measurement sensor positioned above the bed for measuring the color density of the patch printed on the media;
the patch measurement sensor is scannable over the suction hole;
The ink head leaves a gap at the edge of the medium with reference to the scanning direction of the patch measurement sensor, and prints the patch above the suction hole avoiding the suction hole at a position corresponding to the gap. A printer characterized by being capable of 4. A printer according to claim 3 , wherein said patch measurement sensor is fixed to said ink head. 5. A printer according to claim 3, wherein said ink head is capable of printing a plurality of patches with different densities.

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