JPH11291467A - Method for controlling image forming device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of forming an image with high precision on the surface of a medium to be printed. SOLUTION: A conveyance belt 33 with a cloth 1 bonded to the surface is intermittently fed at a specified movement rate by conveying rollers 31, 32. Above the conveyance belt 33, a printing part 61 with an ink jet head 63, an iTV camera 41 and an iTV camera 42 are arranged in that order from the upstream side in the conveyance direction of the cloth 1 on the conveyance belt 33. An image formed on the cloth 1 by the ink jet head 63 is loaded as a registered image into the iTV camera 41. The part loaded as the registered image of the image formed on the cloth 1, is loaded into the iTV camera 42 as a searched image. The image processing device 40 performs a comparative calculation using the registered image and the searched image to calculate a relative positional deviation level between the registered image and the searched image. Finally, a deviation in the movement of the cloth 1 is corrected based on the positional deviation level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a control method of an image forming apparatus for patterning a pattern on a band-shaped print medium such as a cloth, and an image forming apparatus.

[0002]

2. Description of the Related Art As an example of a conventional image forming apparatus, there is, for example, a printing machine disclosed in Japanese Patent Publication No. Sho 60-31728. FIG. 5 is a schematic configuration diagram showing a printing machine disclosed in Japanese Patent Publication No. Sho 60-31728.

In a printing machine disclosed in Japanese Patent Publication No. Sho 60-31728, as shown in FIG.
The endless belt 103 is stretched by the feeding roller 102 and the feeding roller 102. The pair of pulling-side rollers 101 and the sending-out roller 102 and the endless belt 103 constitute a conveying unit. The endless belt 103 is intermittently fed by a predetermined repeat length P by the rotation of the pulling roller 101 and the feed roller 102. Delivery side roller 102
Is provided in the vicinity of, and the glue is applied to a portion of the endless belt 103 that is in contact with the feed-out roller 102 by the glue device 116. Further, a press roller 17 that sandwiches the portion of the endless belt 103 on which the glue is applied with the sending-side roller 102 is provided. When the cloth 120 is fed between the press roller 17 and the endless belt 103, the cloth 120 is glued and fixed on the surface of the endless belt 103 by the paste applied on the endless belt 103.

On the upper traveling path of the endless belt 103, a drawing means having a screen 104 and a cage (not shown) is provided. Each time the endless belt 3 is intermittently fed by the repeat length P and the cloth 120 is conveyed in the direction of arrow A, the screen 4 descends toward the surface of the cloth 120, and the screen 104 is moved by the scanning movement of the screen. The upper color paste is applied on the fabric 120.
Thereby, an image is formed on the surface of the cloth 120. Thereafter, the screen 104 is raised, and thereafter, this cycle is repeated by a predetermined number of colors, thereby completing the print scan.

The pulling roller 101 is provided with a speed reducer 106
The motor is rotated by a DC motor 105a via a. The delivery roller 102 is rotated by a DC motor 105b via a speed reducer 106b. Each of the speed reducers 106a and 106b is used as needed. The DC motor 105a is provided with a tachogenerator 113a for detecting the actual rotation speed of the DC motor 105a, and the DC motor 105b is provided with a tachogenerator 113b for detecting the actual rotation speed of the DC motor 105b.

The pulling roller 101 is provided with a pulse generator 112a.
02 is provided with a pulse generator 112b. The pulse generator 112a causes the pull-side roller 101 to move in accordance with the displacement of the pull-side roller 101.
The actual feed length of the endless belt 103 is detected. Further, the actual feed length of the endless belt 103 at the feed roller 102 is detected by the pulse generator 112b in accordance with the displacement of the feed roller 102.

Further, a digital servo mechanism 13 including a deviation counter 109a, a D / A converter 110a, and a motor control mechanism 111a is provided on the pulling roller 101.
1a is provided. On the delivery roller 102,
A deviation counter 109b, a D / A converter 110b, and a motor control mechanism 111b are provided. The printing machine is provided with a deviation comparison counter 114, a repeat length setting switch 107, and a pulse conversion mechanism.

The deviation comparison counter 114 compares the number of pulses detected by the pulse generator 112a with the number of pulses detected by the pulse generator 112b, and converts the deviation into a correction voltage. To the motor control mechanism 112b.
The repeat length setting switch 107 is connected to the endless belt 1
03 is set, and the repeat length P is displayed. The pulse conversion mechanism 108
The repeat length P set by the repeat length setting switch 107 is converted into a set pulse number, and the converted set pulse number is sent to each of the deviation counters 109a and 109b.

The digital servo mechanism 131a performs a subtraction operation on the number of pulses set from the pulse conversion mechanism 108 and the number of detection pulses from the pulse generator 112a, and calculates the number of pulses set for the pulse conversion mechanism 108 based on the calculation result. The drive of the DC motor 105a is stopped so as to stop the endless belt 103 at the corresponding repeat length. The digital servo mechanism 131b performs a subtraction operation on the number of pulses set from the pulse conversion mechanism 108 and the number of detection pulses from the pulse generator 112b, and based on the calculation result, repeats the number of pulses set on the pulse conversion mechanism 108. The drive of the DC motor 105b is stopped so as to stop the endless belt 103 with a long length.

Next, a description will be given of a method of controlling the printing machine configured as described above. First, the repeat length P set by the repeat length setting switch 107 is determined by the pulse conversion mechanism 1.
08. In the pulse conversion mechanism 108, the repeat length P from the repeat length setting switch 107 is converted into the set pulse number L. The converted set pulse number L
At the same time, the signal is sent to the deviation counter 109a through the wiring 121b. The digital servo mechanism 131a drives the DC current generator 105a to rotate the pulling roller 101, and the digital servo mechanism 131b drives the DC current generator so that the endless belt 103 is fed by the repeat length P based on the set pulse number L. The delivery roller 102 is rotated by driving 105b.

Here, the displacement of the pulling roller 101 is detected by the pulse generator 112a as the number of detection pulses, and the number of detected pulses is determined by the pulse generator 1a.
From 12a, it is sent to the deviation counter 109a through the wirings 115a and 122a. At the same time, the displacement of the delivery roller 102 is changed by the pulse generator 112b.
The number of detected pulses is sent from the pulse generator 112b to the deviation comparison counter 114 through the wirings 115b and 122b. The deviation counter 109a performs a subtraction operation between the set pulse number and the detected pulse number, and an operation pulse is obtained from the operation result. The operation pulse from the deviation counter 109a is converted into a voltage signal by a D / A converter 110a.
The voltage signal is sent to the motor control mechanism 111a. The motor control mechanism 111a sends a predetermined electric input to the DC motor 105a through the wiring 123a based on the sent voltage signal so as to decelerate and stop the DC motor 105a at the set number of pulses. Since the same operation as the deviation counter 109a is performed in the deviation counter 109b, the description is omitted. In this way, the intermittent feeding of the endless belt 103 is reliably performed.

Also, as described above, the endless belt 10
3, when the intermittent feed is performed, the number of detected pulses detected by the pulse
Through to the deviation comparison counter 114. At the same time, the number of detected pulses detected by the pulse generator 112b is sent to the deviation comparison counter 114 through the wirings 115b and 125b. The deviation comparison counter 114 compares the number of detection pulses from the pulse generator 112a with the number of detection pulses from the pulse generator 112b, and converts a deviation obtained by the comparison into a correction voltage. The correction voltage is supplied to the deviation comparison counter 11.
4 is supplied to the motor control mechanism 111b through the wiring 126. The electric motor control mechanism 111b controls the electric power to the DC motor 105b based on the correction voltage from the deviation comparison counter 114 so that the number of pulses detected by the pulse generator 112a is always the same as the number of pulses detected by the pulse generator 112b. Control the input.

Thus, the pulse generator 112a
As soon as there is a difference between the number of detected pulses in the DC motor 105 and the number of detected pulses in the pulse generator 112b, the DC motor 105 is controlled so that both detected pulse numbers become the same.
, The rotational drive of the delivery roller 102 is controlled. As a result, no excessive tension or abnormal stress is locally applied to the endless belt 103, and the elongation and compression of the endless belt 103 are reduced and suppressed, and as a whole, the feeding accuracy of the endless belt 103 is at a high level. Will be maintained.

[0014]

However, in a printing machine disclosed in Japanese Patent Publication No. Sho 60-31728, which is an example of a conventional image forming apparatus, a DC motor, a pulse generator, and a digital motor are provided corresponding to the rollers 101 and 102, respectively. Since the servo mechanism is provided, there is a problem that the configuration of the image forming apparatus and a control method thereof become complicated, and the image forming apparatus becomes expensive.

Further, when the belt is intermittently fed, the difference between the amount of elongation of the belt at each start and the amount of contraction of the belt when the belt stops, and the meandering of the belt are caused by the printing pattern on the fabric. Had a significant effect on the decrease in the positional accuracy of

An object of the present invention is to control an image forming apparatus capable of forming an image on a surface of a printing medium with high accuracy without using a complicated and expensive apparatus for intermittently feeding a belt intermittently and accurately. A method and an image forming apparatus are provided.

[0017]

In order to achieve the above object, a control method of an image forming apparatus according to the present invention is characterized in that a print medium is printed each time a belt-shaped print medium is moved in one direction parallel to the print medium. In a control method of an image forming apparatus for forming an image on a surface of a medium, at least a part of a surface of the medium to be printed is imaged by a first imaging unit every time the medium to be printed is intermittently moved to register a registered image. Capturing, and at least a part of the portion of the surface of the print medium captured as a registered image by the first imaging unit, at a position downstream of the first imaging unit in the moving direction of the print medium. Capturing the search image by capturing the search image by the second imaging unit each time the camera is intermittently moved; and registering the registered image captured by the first imaging unit;
Correcting a shift in the amount of movement of the print medium each time the print medium is intermittently moved, based on the search image captured by the second imaging means.

Further, at least a part of the image formed on the surface of the print medium is captured as a registered image by the first image pickup means, and at least a part of the image captured as the registered image is stored in the second image. It is preferable that the image pickup means captures the search image as a search image, and corrects the displacement of the print medium every time the print medium is intermittently moved based on the registered image and the search image.

Further, a pattern is formed on the surface of the print medium by the constituent material of the print medium, and at least a part of the pattern on the surface of the print medium is captured as a registered image by the first imaging means; Of the pattern,
At least part of the part captured as the registered image
It is preferable that the image pickup means captures the search image as a search image, and corrects the displacement of the print medium every time the print medium is intermittently moved based on the registered image and the search image.

More specifically, the step of storing image data of a registered image captured by the first image capturing means, the step of storing image data of a search image captured by the second image capturing means, The method further includes a step of performing a comparison operation using the image data of the image and the image data of the stored search image, and a step of calculating a moving distance correction amount of the print medium based on the operation result obtained by the comparison operation. .

Further, a normalized correlation operation is performed using the image data of the registered image and the image data of the search image, and a relative position between the registered image and the search image obtained from the operation result of the normalized correlation operation. It is preferable to correct the deviation of the movement amount of the print medium based on the deviation amount.

Further, a portion of the print medium that is separated from the portion imaged by the first imaging means by the same distance as the predetermined amount of movement on the downstream side in the moving direction of the print medium by the second imaging means. It is preferable that the displacement of the print medium is corrected each time the print medium is intermittently moved based on the registered image and the search image, captured as a search image.

Further, the image forming apparatus of the present invention has a conveying means for intermittently moving the band-shaped print medium in one direction parallel to the print medium, and a predetermined moving amount of the print medium by the transfer means. And a drawing unit for forming an image on the surface of the print medium each time the print medium is intermittently moved in the image forming apparatus. A first image capturing unit that captures a registered image, and at least a part of a portion of the surface of the print medium that is captured as a registered image by the first image capturing unit is a first image capturing unit.
A second imaging unit that captures a search image by capturing each time the print medium is intermittently moved downstream of the print medium in the movement direction of the print medium, and a registration image that is captured by the first imaging unit. Moving amount correction control means for controlling the conveying means so as to correct the deviation of the moving amount of the print medium each time the print medium is intermittently moved based on the search image captured by the second imaging means. And further characterized by:

Further, it is preferable that the registered image captured by the first imaging unit and the search image captured by the second imaging unit are images formed on the surface of the printing medium by the drawing unit. Alternatively, a pattern is formed on the surface of the printing medium by the constituent material of the printing medium, and the registered image captured by the first imaging unit and the search image captured by the second imaging unit are displayed on the printing medium. It is preferable that the surface has the pattern.

More specifically, the movement amount correction control means stores at least image data of a registered image captured by the first image capturing means, and an image of a search image captured by the second image capturing means. Search image storage means for storing data; comparison operation means for performing comparison operation using image data of the registered image stored in the registered image storage means and image data of the search image stored in the search image storage means; Correction amount calculating means for calculating the correction amount of the moving distance of the print medium based on the calculation result of the calculating means.

Further, the comparison operation means performs a normalized correlation operation using the image data of the registered image stored in the registered image storage means and the image data of the search image stored in the search image storage means. Is preferred. Also,
The moving amount correction control means corrects a shift in the moving amount of the print medium based on a relative positional shift amount between the registered image and the search image obtained from the calculation result of the normalized correlation calculation by the comparison calculating means. It is preferable to control the transfer means.

Further, the second image pickup means picks up an image of a portion of the print medium that is separated by a predetermined distance from the portion imaged by the first image pickup means on the downstream side in the moving direction of the print medium. It is preferable that

Further, it is preferable that an ink jet head for discharging liquid toward the print medium is used as the drawing means.

In the invention as described above, when an image is formed on the surface of the printing medium every time the belt-shaped printing medium is intermittently moved by a predetermined moving amount, at least a part of the surface of the printing medium is removed. At least a part of the portion of the surface of the print medium captured as the registered image by the first image capturing unit as the registered image and captured by the first image capturing unit is smaller than that of the first image capturing unit. It is captured as a search image by the second imaging means on the downstream side in the moving direction. Then, the print medium moves intermittently by correcting the shift of the movement amount of the print medium based on the registered image captured by the first imaging unit and the search image captured by the second imaging unit. In each case, the displacement of the print medium is eliminated, and the position accuracy of the image formed on the surface of the print medium is improved. Therefore, an image can be formed on the surface of the print medium with high accuracy.

Further, a part of the image formed on the surface of the print medium or a part of the pattern formed on the surface of the print medium by the constituent material of the print medium is captured as a registered image and registered. By capturing at least a part of an image or a pattern captured as an image as a search image, a relative displacement between the registered image and the search image can be obtained, and the displacement of the movement amount of the print medium can be corrected. Here, by performing the normalized correlation operation using the image data of the registered image and the image data of the search image, the shift of the movement amount of the print medium can be accurately obtained.

[0031]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to an embodiment of the present invention. In the image forming apparatus according to the present embodiment, as shown in FIG. 1, an unwind roller 11 for unwinding a cloth 1 as a band-shaped print medium is rotatably attached to one side of the housing 2. I have. The fabric 1 is wound around the unwind roller 11 in a roll shape.
The cloth 1 is unwound in the direction of arrow A from the unwind roller 11 with the rotation of the unwind roller 11.

On the upper part of the housing 2, an unwind roller 11 is provided.
There is provided a transport unit 30 for transporting the fabric 1 unwound from in the direction of arrow B in a substantially horizontal direction. The transport unit 30 includes transport rollers 31 and 32 disposed parallel to and at a distance from each other, and transport rollers 31 and 32.
The conveyor belt 33 wound around the conveyor belt 33 is pressed upward from the rear side of the conveyor belt 33 to apply the optimum tension to the conveyor belt 33, and to maintain a predetermined range of the conveyor belt 33 flat. And a platen roller 34. As the transport rollers 31 and 32 rotate, the transport belt 33 is intermittently fed by a predetermined moving amount L. Therefore, the transport rollers 31 and 32 and the transport belt 33 constitute a transport unit for intermittently moving the fabric 1. As the material of the transport belt 33, a nonmetallic material such as reinforced rubber having sufficient durability is used. On the surface of the conveyor belt 33, an adhesive layer for bonding the fabric 1 to the conveyor belt 33 is formed.

The pair of platen rollers 34 are arranged in parallel with each other, and the portion of the conveyor belt 33 between the pair of platen rollers 34 is kept flat by the pair of platen rollers 34. Thereby, when printing is performed by the printing unit 61 described later, the printing surface of the fabric 1 on the transport belt 33 is supported in a flat state. further,
An iTV camera 41 to be described later is provided on the rear surface of the transport belt 33.
Roller 35a corresponding to iTV and iTV described later
The auxiliary roller 35b corresponding to the camera 42 is in contact. Intermediate rollers 13 and 15 for guiding the fabric 1 from the unwind roller 11 to the transport unit 30 are arranged in the transport path of the fabric 1 between the unwind roller 11 and the transport unit 30.

On the other side of the housing 2, a take-up roller 2 for taking up the cloth 1 conveyed from the conveyance section 30.
1 is rotatably mounted. In the transport path of the fabric 1 between the transport unit 30 and the winding roller 21, feed rollers 17 and 19 for guiding the fabric 1 from the transport unit 30 to the winding roller 21 are arranged. Also,
In the vicinity of the transport roller 31, the cloth 1 is transported by the transport belt 33.
An attaching roller 36 urged in a direction toward the surface of the conveyor belt 33 to press against the surface of the conveyor belt 33 is attached to the housing 2. Further, a drying heater 64 for drying the cloth 1 is provided near the conveying path of the cloth 1 between the conveying roller 32 and the feed roller 17.

Above the transport belt 33, the printing section 6
1. an iTV camera 41 as a first imaging unit;
An iTV camera 42 as a second imaging unit is arranged in this order from the upstream side in the transport direction along the transport direction of the fabric 1 on the transport belt 33. In the printing unit 61, the carriage 62 is parallel to the cloth 1 on the conveyance belt 33 and perpendicular to the conveyance direction of the cloth 1 on the conveyance belt 33, that is, perpendicular to the paper surface of FIG. It is movably supported in the direction. This carriage 6
An inkjet head 63, which is a drawing unit, is mounted on 2. The inkjet head 63 is provided with a pair of platen rollers 34 in the fabric 1 on the transport belt 33.
The liquid printing agent is discharged toward the portion between
An image such as a pattern is printed on the image. The inkjet head 63 is provided with an electrothermal converter that generates thermal energy used to discharge the printing agent. An image is formed on the surface of the cloth 1 by discharging the recording liquid from the ink jet head 63 while scanning the ink jet head 63 by the carriage 62 every time the cloth 1 is intermittently moved by a predetermined moving amount by the transport belt 33. Is done.

The iTV camera 41 transfers the pattern formed on the fabric 1 by the ink jet head 63 to the transport belt 3.
3 is intermittently sent, and the pattern is taken in as a registered image. The iTV camera 42 is an iT
It is arranged at a position away from the V camera 41 by a distance L on the downstream side in the movement direction of the fabric 1. A portion of the cloth 1 separated from the portion imaged by the iTV camera 41 by the same distance as the predetermined moving amount L on the downstream side in the moving direction of the fabric 1 is i
The image is captured by the TV camera 42, and the captured image is captured as a search image. Therefore, iTV of the fabric 1
The pattern captured by the camera 41 is the iTV camera 4
The image is captured by the iTV camera 42 on the downstream side of the cloth 1 in the movement direction.

Further, the image forming apparatus of this embodiment has i
An image processing device 40 is provided for sending registered images and search images captured by the TV cameras 41 and 42, respectively. The image processing device 40 and the iTV camera 41 are connected by a camera cable 43, and the image processing device 4
0 and the iTV camera 44 are connected by a camera cable 44. The image processing device 40 and a control device (not shown) that controls the rotation of the transport rollers 31 and 32 constitute a movement amount correction control unit.

FIG. 2 is a top view of the printing section 61 and the transport section 30 of the image forming apparatus shown in FIG. FIG. 2 shows a block diagram of the image processing apparatus 40 shown in FIG. As shown in FIG. 2, the image processing device 40 includes a multiplexer 45, an A / D converter 46, a registered image memory 47 as registered image storage means, a search image memory 48 as search image recording means, and a comparison image processing means. A comparison arithmetic unit 49, a CPU 50 as a correction amount arithmetic unit,
An image data bus 51 is provided. Registered image memory 47
Stores the image data of the registered image captured by the iTV camera 41. The search image memory 48 stores the iTV
Image data of the search image captured by the camera 42 is stored. The comparison calculator 49 performs a normalized correlation operation as a comparison operation using the image data of the registered image stored in the registered image memory 47 and the image data of the search image stored in the search image memory 48. .

Next, the operation of the above-described image forming apparatus will be described. First, the cloth 1 wound around the unwinding roller 11 is unwound from the unwinding roller 11 with the rotation of the unwinding roller 11. The fabric 1 unwound from the unwind roller 11 is transported to the transport unit 30 via the intermediate rollers 13 and 15. The cloth 1 transported to the transport unit 30 is transported by the transport belt 33 and the attaching roller 36.
The cloth 1 is adhered and fixed to the surface of the transport belt 33 by being pressed between the belt 1 and the transport belt 33.
The cloth 1 adhered to the transport belt 33 is intermittently transported by the transport belt 33 by a predetermined moving amount L. By discharging the printing agent from the inkjet head 63 while scanning the inkjet head 63 with the carriage 62 in a state where the transport belt 33 is stopped, a predetermined pattern such as a pattern is formed on the surface of the fabric 1 where the print unit 61 faces. An image is formed. In this way, the fabric 1 is intermittently conveyed every time printing is performed by the inkjet head 63. When transporting the fabric 1 intermittently, the fabric 1
Is shifted from the predetermined movement amount L, the control for correcting the displacement of the cloth 1 is performed every time the cloth 1 is intermittently moved. A control method for correcting the displacement of the movement amount of the cloth 1 will be described later.

The fabric 1 on which the printed pattern is printed by the ink jet head 63 is peeled off from the transport belt 33 near the transport roller 32, and is heated by the drying heater 64 until the peeled fabric 1 reaches the feed roller 17. . Thereby, the printing agent on the fabric 1 dries. Thereafter, the fabric 1 is wound by the winding roller 21 via the feed rollers 17 and 19.

Next, a control method of the image forming apparatus shown in FIGS. 1 and 2 will be described with reference to a flowchart of FIG.

First, after receiving a command from a host computer (not shown) for controlling the entire sequence of the image forming apparatus, the carriage 62 is returned to the origin for the next operation, and then the transport belt 33 is stopped. In this state, a pattern is printed on the surface of the fabric 1 by the inkjet head 63 (S1). With the transport belt 33 stopped, the pattern printed on the cloth 1 by the inkjet head 63 is captured by the registered image iTV camera 41 and the registered image is captured (S2). iTV camera 4
The image data of the registered image captured by the A / D converter 1 is converted into an analog signal via the multiplexer 45 by the A / D converter 4.
The analog signal of the registered image is converted into a digital signal by the A / D converter 46. A / D converter 46
The image data of the registered image converted to a digital signal by
The data is sent to the registered image memory 47 via the image data bus 51 and stored in the registered image memory 47.

FIG. 4 shows an image captured by the iTV camera 41.
Registered images and images captured by the iTV camera 42.
It is a figure showing a search image. In the present embodiment, the ink jet
Pattern formed on the fabric 1 by the cut head 63
That is, the image capture area I shown in FIG._aIs the iTV turtle
The image is taken by the camera 41. Then, the image capture area I
_aAmong the registered image areas R_aThe image data of the part is registered
Stored in the registered image memory 47 as image data of the image.
You. The image data of the registered image stored in the registered image memory 47
The data is sent to the comparator 49 via the image data bus 51.
Sent.

[0045] Immediately after incorporating region I _a capture image of a reference image by iTV camera 41, at the instruction of the host computer, after the fabric 1 was run the conveyor belt 33 to move by a predetermined amount of movement L (S3) , Conveyor belt 3
3 is stopped (S4).

Next, a pattern on the cloth 1 is imaged by the search image iTV camera 42 and the search image is captured (S
5). The image data of the search image captured by the iTV camera 42 is sent as an analog signal to the A / D converter 46 via the multiplexer 45, and the analog signal of the search image is converted to a digital signal by the A / D converter 46. You. The image data of the search image converted into a digital signal by the A / D converter 46 is sent to the search image memory 48 via the image data bus 51 and stored in the search image memory 48.

[0047] Here, among the patterns formed on the cloth 1 by the inkjet head 63, the portion of the region I _b capture images shown in FIG. 4 is imaged by the iTV camera 42 as the search image. Then, data of the image part of the registered image region R _a in the region I _a capture image is stored in the search image memory 48 as image data of the search image. The image data of the search image stored in the search image memory 48 is
The data is sent to the comparison arithmetic unit 49 via the image data bus 51.

In the comparison operation unit 49, the registered image memory 47
Image data of the registered image from the search image memory 4
Then, a normalized correlation operation is performed using the image data of the search image from No. 8 to calculate a relative displacement amount between the registered image and the search image (S6). Here, the registered image in the registration image region R _a shown in FIG. 4, determine whether present in the position of the region I _b throat image capture. For example, the transport belt 33
It is offset moving amount of the cloth 1 by a distance [delta] from the predetermined amount of movement L by, when the fabric 1 is moved by the amount of movement (L + [delta]), as shown in FIG. 4, the registration image in the registration image region R _a The pattern and the pattern of the search image in search image region _Rb are relatively shifted by a distance δ. The relative displacement amount δ between the registered image and the search image is calculated by the comparison calculator 49 as a calculation result. Then, it is determined whether the positional deviation amount δ is equal to or less than the allowable value (S7).

[0049] and the pattern of the registered image in the registration image area _{I a,}
If the relative positional deviation between the pattern of the search image in the search image area I _b [delta] is less than the allowable value, the stop position fabric 1 is determined that there is normal, the ink jet head 63
Then, the printing agent is discharged toward the fabric 1 to print a pattern on the fabric 1 (S12).

When the positional deviation amount δ is larger than the allowable value, the CPU 50 calculates the correction amount of the moving distance of the conveyor belt 33 based on the calculation result of the comparison calculator 49. This movement distance correction amount is used for the communication I / O and the communication cable 52.
Control device for conveying rollers 31 and 32 (not shown)
The moving distance of the cloth 1 is corrected by differentially moving the conveyor belt 33 by the control device (S8). Then, in the same manner as described above, the pattern on the cloth 1 is captured as a search image by the iTV camera 42 (S9). The relative displacement between the fetched search image and the already fetched registered image is calculated by the comparison calculator 49 in the same manner as described above (S10). Thereafter, it is determined whether or not the calculated positional deviation amount is equal to or less than an allowable value (S11). If the amount of misalignment is equal to or less than the allowable value, a pattern is printed on the fabric 1 by the inkjet head 63 (S12). If the amount of misalignment is greater than the allowable value, the same movement distance of the fabric 1 as described above is used. Correction is performed. In this way, the same processing is repeated until the relative displacement between the registered image and the search image becomes equal to or smaller than the allowable value.

The processing described above is performed each time the transport belt 33 is intermittently fed, and a pattern is formed on the cloth 1 by the ink jet head 63 in a state where the cloth 1 is not displaced. In the image forming apparatus of the present embodiment, the pattern formed on the fabric 1 by the inkjet head 63 is i
Although the images were taken and captured by the TV cameras 41 and 42, a pattern was formed on the surface of the fabric 1 on the inkjet head 63 side by the constituent material of the fabric 1, and the registered images were obtained by capturing the patterns by the iTV cameras 41 and 42. Captured as search images, based on those images,
The processing as described above may be performed. In this case, iTV
The cameras 41 and 42 are arranged on the cloth 1
May be arranged on the upstream side in the transport direction.

As described above, in the image forming apparatus of the present embodiment, the transport belt 33 to which the cloth 1 is adhered and fixed is intermittently fed by a predetermined moving amount L, and the cloth 1 moves intermittently. When a pattern is formed on the surface of the fabric 1 by the inkjet head 63 every time, a part of the pattern on the surface of the fabric 1
1 as a registered image, and the iTV
The portion captured by the camera 41 is captured as a search image by the iTV camera 42 on the downstream side in the movement direction of the fabric 1. Then, based on the registered image captured by the iTV camera 41 and the search image captured by the iTV camera 42, the transport rollers 31 and 32 are rotated to fabric 1
Is corrected. Thereby, the displacement of the cloth 1 due to the intermittent movement of the cloth 1 is eliminated, and the positional accuracy of the image formed on the surface of the cloth 1 is improved, so that an image is formed on the surface of the cloth 1 with high accuracy. Is done. Also,
Unlike a conventional image forming apparatus, there is no need to provide a pulse generator or a digital servo mechanism for each of a pair of rollers for intermittently feeding the belt, so that the cost of the image forming apparatus is reduced.

[0053]

As described above, according to the present invention, when an image is formed on the surface of a printing medium every time the belt-shaped printing medium is intermittently moved by a predetermined movement amount, the surface of the printing medium can be printed. A part is taken in as a registered image by the first image pickup means, and at least a part of a part of the surface of the print medium which is taken in as the registered image is taken in as a search image by the second image pickup means. The displacement of the movement amount of the print medium is corrected based on the above, so that the position shift of the print medium when forming an image on the print medium is eliminated, and the image is formed with high accuracy on the surface of the print medium. . Further, unlike a conventional image forming apparatus, there is no need to provide a pulse generator, a digital servo mechanism, or the like corresponding to each of a pair of rotors for intermittently moving a print medium,
The cost of the image forming apparatus is reduced. Therefore, there is an effect that an image forming apparatus that can form an image with high accuracy at low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a top view of a transport unit and a printing unit of the image forming apparatus shown in FIG.

FIG. 3 is a flowchart illustrating a control method of the image forming apparatus illustrated in FIGS. 1 and 2;

FIG. 4 shows a registered image captured by the registered image iTV camera shown in FIGS. 1 and 2, and a search image i
It is a figure showing the search image picturized by the TV camera.

FIG. 5 is a schematic configuration diagram illustrating an example of an image forming apparatus according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cloth 2 Case 11 Unwind roller 13, 15 Intermediate roller 17, 19 Feed roller 21 Take-up roller 30 Transport unit 31, 32 Transport roller 33 Transport belt 34 Platen roller 35a, 35b Auxiliary roller 36 Pasting roller 40 Image processing device 41, 42 iTV camera 43, 44 Camera cable 45 Multiplexer 46 A / D converter 47 Registered image memory 48 Search image memory 49 Comparison arithmetic unit 50 CPU 51 Image data bus 52 Communication cable 61 Printing unit 62 Carriage 63 Inkjet head 64 Drying heater _Ia , _Ib image capturing area _Ra registered image area _Rb search image area

Claims (15)

[Claims] 1. A method for controlling an image forming apparatus for forming an image on a surface of a printing medium each time a belt-shaped printing medium is intermittently moved in one direction parallel to the printing medium, the method comprising: Capturing a registered image by capturing at least a part of the surface of the print medium by the first imaging unit every time the print medium is intermittently moved; Each time the printing medium is intermittently moved at least part of the portion captured as the registered image by the imaging means downstream of the first imaging means in the moving direction of the printing medium, Capturing the search image by capturing by the image capturing means, and the registered image captured by the first capturing means and before capturing by the second capturing means. Correcting the displacement of the movement amount of the print medium each time the print medium is intermittently moved based on the search image. 2. The method according to claim 1, wherein at least a part of the image formed on the surface of the print medium is captured by the first imaging unit as the registered image, and at least a part of the image captured as the registered image. A part is taken in as the search image by the second imaging means, and based on the registered image and the search image, each time the print medium is intermittently moved, a shift in the movement amount of the print medium is corrected. The method for controlling an image forming apparatus according to claim 1. 3. A pattern is formed on a surface of the print medium by a constituent material of the print medium, and at least a part of the pattern on the surface of the print medium is registered by the first imaging unit. Import as an image,
In addition, at least a part of the portion of the pattern captured as the registered image is captured as the search image by the second imaging unit, and the print medium is intermittently intermittently based on the registered image and the search image. 2. The control method according to claim 1, wherein a shift in the amount of movement of the print medium is corrected each time the medium is moved. 4. A step of storing image data of the registered image captured by the first image capturing means, and a step of storing image data of the search image captured by the second image capturing means. Performing a comparison operation using the image data of the registered image and the stored image data of the search image; and calculating a travel distance correction amount of the print medium based on the operation result obtained by the comparison operation. The method for controlling an image forming apparatus according to claim 1, further comprising: 5. The method according to claim 4, wherein a normalized correlation operation is performed as the comparison operation using the image data of the registered image and the image data of the search image. 6. The method according to claim 5, wherein a displacement of the movement amount of the print medium is corrected based on a relative displacement amount between the registered image and the search image obtained from the calculation result of the normalized correlation calculation. The control method of the image forming apparatus described in the above. 7. A part of the medium to be printed, which is separated by a distance equal to the predetermined amount of movement from the part imaged by the first imaging means to the downstream side in the moving direction of the medium to be printed, 7. The image capturing means according to claim 1, wherein the displacement of the print medium is corrected each time the print medium is intermittently moved based on the registered image and the search image. The control method of the image forming apparatus according to any one of the above. 8. A transport means for intermittently moving a band-shaped print medium in one direction parallel to the print medium, and intermittently moving the print medium by the transport amount by the transport means. And a drawing unit for forming an image on the surface of the print medium each time the print medium is moved, wherein at least a part of the surface of the print medium is intermittently moved every time the print medium is moved. A first imaging unit that captures a registered image, and at least a part of a portion of the surface of the print medium that is captured as the registered image by the first imaging unit is a first imaging unit. A second imaging unit that captures a search image by capturing an image each time the print medium is intermittently moved downstream of the print medium in the movement direction of the print medium; Registered image captured by the imaging means and,
Based on the search image captured by the second imaging means,
An image forming apparatus further comprising: a movement amount correction control unit that controls the transport unit so as to correct a shift in the movement amount of the print medium every time the print medium is intermittently moved. . 9. The registration image captured by the first imaging unit and the search image captured by the second imaging unit are the same as the image formed on the surface of the print medium by the drawing unit. The image forming apparatus according to claim 8. 10. A pattern is formed on a surface of the print medium by a constituent material of the print medium, and the registered image captured by the first image capturing unit and the pattern captured by the second image capturing unit. The image forming apparatus according to claim 8, wherein the search image is the pattern on a surface of the print medium. 11. A registered image storage unit for storing at least image data of the registered image captured by the first imaging unit, wherein the movement amount correction control unit includes: a search image captured by the second imaging unit; A search image storage unit that stores the image data of the search image; a comparison operation using the image data of the registered image stored in the registered image storage unit and the image data of the search image stored in the search image storage unit The image forming apparatus according to claim 8, further comprising: a comparison operation unit; and a correction amount operation unit configured to calculate a correction amount of a movement distance of the print medium based on an operation result of the comparison operation unit. 12. The image data of the registered image stored in the registered image storage means, wherein the comparison operation means includes:
The image forming apparatus according to claim 11, wherein a normalized correlation operation is performed using image data of the search image stored in the search image storage unit. 13. The printing medium based on a relative displacement between the registered image and the search image obtained from a calculation result of a normalized correlation calculation by the comparison calculation unit. 13. The image forming apparatus according to claim 12, wherein the control unit controls the transport unit so as to correct a shift of the moving amount of the image forming apparatus. 14. The printing apparatus according to claim 1, wherein the second imaging unit is located on a downstream side in a moving direction of the printing medium from a portion of the printing medium which is imaged by the first imaging unit by the same distance as the predetermined movement amount. The image forming apparatus according to claim 8, wherein an image of a distant portion is taken. 15. The image forming apparatus according to claim 8, wherein an ink jet head that discharges a liquid toward the print medium is used as the drawing unit.