LIQUID EJECTION APPARATUS, LIQUID EJECTION METHOD, AND PROGRAM

Abstract

To improve accuracy for landing liquid.SOLUTION: A liquid discharge device includes: a conveyance section which conveys a recording medium in a conveyance direction using a rotor; a first detection section which detects first detection amount indicating rotation amount of the rotor; a second detection section which detects second detection amount indicating a position in the conveyance direction of the recording medium, conveyance speed in the conveyance direction of the recording medium or a combination of them on the basis of a pattern possessed by the recording medium specified by photographing the recording medium; a correction section which calculates second timing obtained by correcting first timing for discharging liquid fixed by the first detection amount on the basis of the second detection amount; and a discharge section which discharges the liquid to the recording medium at the second timing.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a liquid ejection apparatus, a liquid ejection method, and a program. [Background technology]

[0002] 2. Description of the Related Art Techniques for forming images by ejecting liquid such as ink from an inkjet head are known.

[0003] Specifically, the printing device has an upstream roller and a downstream roller that rotate in response to the transported web. An upstream encoder and a downstream encoder that output a pulse signal according to the rotation angle are provided on the upstream roller and the downstream roller. In this manner, the printing device is provided with encoders located near the inkjet heads and corresponding to each inkjet. A technology is known that uses these encoders to prevent deviations in the ink landing position and reduce degradation in print image quality (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 has a problem in that the accuracy with which the liquid is dropped can easily decrease if the roller or the like becomes eccentric, the recording medium slips relative to the roller, or the recording medium expands or contracts.

[0005] An object of the present invention is to improve the accuracy with which liquid is dropped. [Means for solving the problem]

[0006] In order to solve the above problems, a liquid ejection device according to one aspect of the present invention comprises: a conveying unit that conveys the recording medium in a conveying direction using a rotating body; A first detection unit that detects a first detection amount that indicates an amount of rotation of the rotating body; a second detection unit that detects a second detection amount indicating a position of the recording medium in the transport direction, a transport speed of the recording medium in the transport direction, or a combination thereof, based on a pattern of the recording medium identified by photographing the recording medium; a correction unit that calculates a second timing by correcting a first timing for ejecting liquid, the first timing being determined by the first detection amount, based on the second detection amount; a discharge unit that discharges the liquid onto the recording medium at the second timing; The present invention is characterized by comprising: Effect of the Invention

[0007] According to the present invention, the accuracy with which liquid is dropped can be improved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of an image forming apparatus 100. FIG. [Diagram 2] FIG. 1 is a diagram illustrating an example of the configuration of a liquid ejection device. [Diagram 3] FIG. 13 is a diagram showing an example before the timing of ejecting liquid is corrected. [Figure 4] 13A and 13B are diagrams illustrating an example after the timing of ejecting liquid is corrected. [Diagram 5] FIG. 11 is a diagram illustrating an example of correction in the second embodiment. [Figure 6] FIG. 13 is a diagram illustrating an example of changing the reference timing. [Figure 7] FIG. 13 is a diagram illustrating an example of the overall process. [Figure 8] FIG. 2 is a diagram illustrating an example of a functional configuration. [Figure 9] FIG. 13 is a diagram showing the overall configuration of a modified example. [Figure 10] FIG. 2 is a diagram showing an example of a configuration for detecting the position of a recording medium using an image sensor 52. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, specific examples will be described with reference to the accompanying drawings. Note that the embodiment is not limited to the specific examples described below.

[0010] [First embodiment] An example of a case where a liquid ejection device forms an image will be described below. That is, in the example described below, the liquid ejected by the liquid ejection device is ink, and an image is formed when the ink lands on a sheet of paper, which is an example of a recording medium.

[0011] [Example of overall configuration of image forming device] 1 is a diagram showing an example of the overall configuration of an image forming apparatus 100. For example, the image forming apparatus 100 is configured with a paper feeder 101, an inkjet device 102 which is an example of a liquid ejection device, and a paper ejection device 103. Note that the image forming apparatus 100 may also include other devices that perform post-processing, etc.

[0012] The following description will be given taking as an example a case where the paper is a continuous sheet, a so-called web 104. However, the recording medium does not have to be a continuous sheet. For example, the recording medium may be cut paper or the like. Also, when cut paper is used, the image forming apparatus 100 may be configured to move a belt that carries and transports the recording medium.

[0013] In the following description, the conveying direction is referred to as the "conveying direction Y." Specifically, in the drawings, the conveying direction Y is from right to left. The vertical direction is referred to as the "vertical direction Z," and the direction perpendicular to the conveying direction is referred to as the "orthogonal direction X." In the following description, the side where paper is fed may be referred to as the "upstream" (the right side in the drawings), and the side where paper is discharged may be referred to as the "downstream" (the left side in the drawings).

[0014] The paper feeder 101 feeds the web 104 to the inkjet device 102. The inkjet device 102 then forms an image by ejecting ink onto the web 104. Thereafter, the paper ejection device 103 ejects the web 104.

[0015] The inkjet device 102 forms images in, for example, four colors: K, C, M, and Y. In the example shown, the inkjet device 102 includes a K head 210K that ejects K ink, a C head 210C that ejects C ink, an M head 210M that ejects M ink, and a Y head 210Y that ejects Y ink.

[0016] A transport roller 105, which is an example of a rotating body, is installed, for example, upstream of any of the heads and downstream of the paper feeder 101. Note that there may be other rollers, actuators, control devices, etc. that transport the recording medium.

[0017] A detector that detects the amount of rotation is provided for the conveying roller 105. For example, the detector is an encoder 106.

[0018] The encoder 106 detects, as a detection amount, a rotation angle, a rotation speed, or both of the conveying roller 105. That is, the encoder 106 detects, for example, an amount of the recording medium conveyed by the conveying roller 105. Below, an example will be described in which the detection amount detected by the encoder 106 is the "first detection amount."

[0019] 2 is a diagram showing an example of the configuration of a liquid ejection device. For example, the inkjet device 102 includes a transport roller 105, an encoder 106, a K head 210K, a C head 210C, an M head 210M, a Y head 210Y, a driven roller 220, and the like.

[0020] The inkjet device 102 also includes a first image sensor 52A, a second image sensor 52B, a third image sensor 52C, and a fourth image sensor 52D. Hereinafter, the first image sensor 52A, the second image sensor 52B, the third image sensor 52C, and the fourth image sensor 52D may be collectively referred to as the "image sensor 52."

[0021] The inkjet device 102 further includes a controller 520 and a computing device 530 .

[0022] The encoder 106 generates pulses in response to the rotation of the conveyance roller 105. After generation, the encoder 106 transmits the pulses to the calculation device 530.

[0023] The image sensor 52 periodically captures an image of the surface of the web 104. After capturing an image, the image sensor 52 transmits the captured image data to the computing device 530. The computing device 530 then detects a pattern formed on the surface of the web 104 based on the captured image data. Note that the image sensor 52 may also target a pattern or the like inside the web 104.

[0024] The computing device 530 then calculates the displacement of the pattern. In this manner, the computing device 530 calculates the position of the web 104, the transport speed, or both.

[0025] As shown in the figure, the image sensor 52 may be installed upstream of the landing position of the ink ejected from each head. In this way, when the image sensor 52 is installed at a position other than the landing position of the ink, the calculation device 530 may convert it into the landing position of the ink and calculate the position, the transport speed, or both.

[0026] Hereinafter, the detection result by the image sensor 52 will be referred to as a "second detection amount."

[0027] The controller 520 is a storage device, an arithmetic device, a control device, etc. For example, the controller 520 performs control such as causing each head to eject ink at a timing based on the calculation results by the arithmetic device 530, etc. In this manner, the controller 520 controls devices such as each head. Note that the inkjet device 102 may have a device that performs control other than the controller 520.

[0028] [Detection and correction example] 3 is a diagram showing an example before the timing of ejecting liquid is corrected. Below, an example will be described in which the encoder 106 generates a first pulse like the first signal SIG1.

[0029] The first signal SIG1 is a signal indicating a first detection amount. For example, the first signal SIG1 has one period of 10. Specifically, the period 10 indicates one rotation of the conveying roller 105. However, the period 10 is not limited to one rotation, and may be another amount of rotation set in advance.

[0030] The second signal SIG2 is a signal that indicates the timing for ejecting liquid. That is, each head is controlled to eject liquid at the timing indicated by the second signal SIG2. Also, in this example, the second signal SIG2 is high-active. That is, in the figure, when the second signal SIG2 becomes "High", each head ejects liquid.

[0031] For example, when the timing for ejecting liquid is determined based on the first detection amount, the timing is determined as an eleventh timing T11, a twelfth timing T12, a thirteenth timing T13, etc. Hereinafter, the timing determined by the first detection amount, such as the eleventh timing T11, the twelfth timing T12, the thirteenth timing T13, etc., that is, the timing for ejecting liquid before correction, will be referred to as the "first timing."

[0032] The following describes an example in which ejection is performed once every 10 cycles. First, the first timing is determined by the falling edge, for example, as shown in Fig. 3. The first timing thus determined is corrected based on the third signal SIG3 etc. as described below.

[0033] The third signal SIG3 is a signal indicating the second detection amount. Specifically, in the illustrated example, the third signal SIG3 has an initial value of "0." That is, when the correction amount is "0," no deviation or the like occurs, and ejection can be performed at the eleventh timing T11, the twelfth timing T12, and the thirteenth timing T13 without correction.

[0034] Next, this is an example in which the correction amount is calculated to be "A" based on the pattern detected by the image sensor 52. Therefore, the value of the third signal SIG3 is updated from "0" to "-A" at update timing T1 based on the calculation result. Note that "+" and "-" in the correction amount indicate whether the timing is advanced or delayed in the transport direction.

[0035] For example, the correction is performed when a fluctuation in the transport speed occurs. Specifically, when the transport speed fluctuates while the recording medium is being transported, discharging liquid at the timing set in the initial state will cause a deviation in image formation, etc. Therefore, the inkjet device 102 calculates the transport speed based on the displacement of the pattern detected by the image sensor 52, etc. Through such calculations, the inkjet device 102 calculates the fluctuation in the transport speed, etc. Then, when the fluctuation in the transport speed is calculated, the inkjet device 102 grasps the deviation caused by the fluctuation in the transport speed. Next, the inkjet device 102 calculates a correction amount to cancel out the deviation.

[0036] The correction amount may be calculated taking into consideration factors other than the fluctuation in the transport speed. For example, when the position where the image sensor detects the image differs from the position directly below each head, the correction amount may be calculated assuming the position directly below each head.

[0037] In the following, an example will be described in which the correction amount calculated at the update timing T1 is used to correct the ejection timing at the 13th timing T13 before correction. That is, in the following description, an example will be described in which the "first timing", which is the timing at which liquid is ejected and which is determined by the first detection amount, is the 13th timing T13.

[0038] It is preferable that the correction amount be calculated based on the count value of the second pulse as follows.

[0039] The fourth signal SIG4 is a signal indicating a second pulse. The second pulse is a signal obtained by equally dividing the first pulse. Note that the number of equal parts into which the first pulse is divided to obtain the second pulse is set in advance.

[0040] Hereinafter, before correction, the time from the start of cycle 10 (in the figure, shown by the falling edge of the first signal SIG1) to the timing of ejecting liquid (hereinafter referred to as "ejection timing 11") is the "n"th second pulse count value. Also, before correction, the twelfth timing T12 and the thirteenth timing T13 are also assumed to be the "n"th ejection timing 11 in terms of the second pulse count value.

[0041] It is desirable to correct the thirteenth timing T13 using the count value of the second pulse. In this way, by using the count value of the second pulse, the inkjet device 102 can perform processing such as correction by signal processing. Therefore, the inkjet device 102 can perform processing such as correction at high speed compared to the case where software is used.

[0042] Fig. 4 is a diagram showing an example after the timing of ejecting liquid is corrected. Compared to Fig. 3, Fig. 4 differs in that the first timing T13 in Fig. 3 has been corrected to the second timing T2 as shown in Fig. 4.

[0043] The second timing T2 is a timing that is corrected so that the ejection timing 11 before correction is delayed by a correction amount 12. For example, the second timing T2 is preferably calculated using the count value of the second pulse, such as "ejection timing 11 + correction amount 12" being the "m"th second pulse count value. In this way, the correction amount 12 is preferably calculated by converting it into how many second pulses it is.

[0044] For example, fluctuations in the transport speed occur due to factors such as eccentricity of the rotating body, slippage of the recording medium relative to the rotating body, expansion and contraction of the recording medium, or a combination of these. The difference between the first timing and the recording medium at the position where each head lands the liquid due to these factors is the correction amount of 12 minutes. Therefore, the liquid ejection device corrects by the correction amount of 12 minutes.

[0045] In this way, the first timing determined based on the first detection amount indicating the amount of rotation of the rotor is corrected based on the second detection amount determined by the detection result of the image sensor 52, etc. By ejecting liquid at the second timing generated by such correction, the liquid ejection device can reduce positional deviations due to the above-mentioned factors and improve the accuracy of landing the liquid.

[0046] The correction may be a process in which the timing is advanced from before the correction according to the correction amount "+" or "-" (in the figure, the correction is to move the timing to the left from before the correction).

[0047] 2, in a liquid ejection device equipped with a plurality of heads, it is preferable to provide each head with an image sensor 52. It is preferable that the ejection timing of each head is corrected based on the second detection amount by each image sensor.

[0048] It is desirable that the ejection timing of the downstream heads be corrected based on the correction results for the upstream heads. In the case where the heads are arranged from upstream to downstream in the order of K, C, M, and Y as shown in Figure 2, for example, it is desirable that the C head 210C be corrected based on the correction results for the upstream K head 210K.

[0049] Heads located downstream, such as C, M, and Y, are more likely to accumulate deviations when the encoder 106 is used as a reference. In other words, when the encoder 106 is used as a reference, the more downstream the head is, the more likely the deviation is to become large. Therefore, it is desirable to make corrections by referring to the correction results from the upstream heads.

[0050] Specifically, it is desirable to correct the difference with respect to the correction result from the upstream. It is desirable for C head 210C to correct the deviation that occurs downstream of K head 210K after correction has been made to K head 210K. In this way, by correcting the difference with the upstream ejection unit, the liquid ejection device can further improve the accuracy of landing liquid.

[0051] [Second embodiment] In the second embodiment, for example, the following correction is performed.

[0052] FIG. 5 is a diagram showing an example of correction in the second embodiment. Compared to the first embodiment, the difference is that the correction amount 12 is large. Specifically, the correction amount 12 targeted in the second embodiment is a correction amount for one or more periods of the first pulse. Hereinafter, the correction amount will be referred to as "-B".

[0053] In this way, when the correction amount 12 is large, it is desirable for the inkjet device 102 to change the timing that serves as the reference for the second timing T2 (hereinafter referred to as the "reference timing").

[0054] 6 is a diagram showing an example of changing the reference timing, which illustrates an example in which the reference timing is changed to a fourteenth timing T14.

[0055] Before the change, the reference timing is the thirteenth timing T13. Therefore, the inkjet device 102 changes the reference timing from the thirteenth timing T13 to the fourteenth timing T14. That is, the reference timing is changed so as to be delayed by one period of the first signal SIG1. Note that, if the correction amount 12 is two or more periods, the reference timing may be changed by two or more periods.

[0056] In this way, when the reference timing is changed to the fourteenth timing T14, the second timing T2 is calculated as a changed correction amount 13.

[0057] If the reference timing is not changed, the counter value, etc., will become large, as in the correction amount 12, and the control counter may overflow (also called "overflow"). In particular, when the transport speed fluctuates greatly, such as one cycle, two cycles, etc., the correction amount tends to accumulate. And when the control counter overflows, ejection defects may occur.

[0058] On the other hand, if the reference timing is changed, the correction amount 12 can be expressed as a small value such as the changed correction amount 13. Therefore, if the reference timing is changed, overflow of the control counter can be prevented.

[0059] [Overall processing example] FIG. 7 is a diagram illustrating an example of the overall process.

[0060] In step S0701, the liquid ejection device performs a transport procedure for transporting the recording medium by a rotating body. Specifically, the liquid ejection device transports the recording medium from upstream to downstream as shown in FIG.

[0061] In step S0702, the liquid ejection device performs a first detection procedure to detect a first detection amount. Specifically, the liquid ejection device generates a signal indicative of the first detection amount, such as the first signal SIG1 shown in FIG.

[0062] In step S0703, the liquid ejector performs a second detection procedure to detect the second detection amount. Specifically, the liquid ejector generates a signal indicative of the second detection amount, such as the third signal SIG3 shown in FIG.

[0063] In step S0704, the liquid ejection device performs a correction procedure to correct the first timing and calculate the second timing. Specifically, the liquid ejection device corrects the thirteenth timing T13 shown in FIG. 4 to calculate the second timing T2.

[0064] In step S0705, the liquid ejection device performs an ejection procedure for ejecting liquid. Specifically, the liquid ejection device is controlled so as to eject liquid at the second timing T2 shown in FIG.

[0065] It should be noted that the liquid ejection apparatus does not have to perform the entire process in the order shown in the figure. For example, each step may be performed in parallel, redundantly, or in an order different from that shown in the figure.

[0066] [Example of functional configuration] 8 is a diagram showing an example of a functional configuration of the inkjet device 102. For example, the inkjet device 102 includes a transport unit 102F1, a first detection unit 102F2, a second detection unit 102F3, a correction unit 102F4, and a discharge unit 102F5.

[0067] The conveying unit 102F1 performs a conveying procedure of conveying the recording medium in a conveying direction by using a rotating body. For example, the conveying unit 102F1 is realized by a conveying roller 105 or the like.

[0068] The first detector 102F2 performs a first detection procedure to detect a first detection amount. For example, the first detector 102F2 is realized by the encoder 106 or the like.

[0069] The second detector 102F3 performs a second detection procedure to detect a second detection amount. For example, the second detector 102F3 is realized by the image sensor 52 or the like.

[0070] The correction unit 102F4 performs a correction procedure to correct the first timing based on the second detection amount and calculate the second timing. For example, the correction unit 102F4 is realized by the arithmetic device 530 or the like.

[0071] The ejection unit 102F5 performs an ejection procedure for ejecting liquid onto the recording medium at the second timing. For example, the ejection unit 102F5 is realized by the K head 210K, the C head 210C, the M head 210M, and the Y head 210Y, the controller 520, and the like.

[0072] With the above-described functional configuration, the inkjet device 102 can first calculate the first timing based on the first detection amount. Then, if a fluctuation in the transport speed occurs, the accuracy of landing the liquid at the first timing may deteriorate. Therefore, the inkjet device 102 corrects the first timing and calculates the second timing based on the second detection amount determined by the detection result of the image sensor 52, etc. By ejecting the liquid at the second timing generated by such correction, the liquid ejection device can reduce positional deviation and improve the accuracy of landing the liquid.

[0073] [Example of liquid ejection system] A liquid ejection system having a liquid ejection device may have the following configuration.

[0074] 9 is a diagram showing the overall configuration of a modified example. For example, the liquid ejection system is an image forming apparatus 100a having the following overall configuration.

[0075] For example, the image forming apparatus 100a includes a paper feeder 201, a treatment liquid application device 202, a first inkjet device 102a, which are examples of liquid ejection devices, a reversing device 203, and a second inkjet device 102b.

[0076] The web 104 is an example of a continuous conveyed object. Thus, the recording medium may be, for example, a roll of paper.

[0077] The paper feeder 201 transports the web 104 to the treatment liquid applicator 202 .

[0078] The treatment liquid application device 202 performs pretreatment on the web 104. For example, the treatment liquid application device 202 applies treatment liquid to the front and back sides of the web 104.

[0079] The first inkjet device 102a forms an image or the like by ejecting liquid such as ink onto the web 104. For example, the first inkjet device 102a forms an image indicated by image data on the front surface of the web 104.

[0080] The inverting device 203 inverts the web 104 .

[0081] The second inkjet device 102b forms an image or the like by ejecting liquid such as ink onto the web 104. For example, the second inkjet device 102b forms an image indicated by image data on the rear surface of the web 104.

[0082] The image forming apparatus 100a may not necessarily have the configuration as shown in the figure. For example, the image forming apparatus 100a may further include a device that performs pre-processing or post-processing of a type other than that shown in the figure. The number of liquid ejection devices may be one or three or more.

[0083] [Example of configuration for detecting the position of a recording medium] 10 is a diagram showing an example of a configuration for detecting the position of a recording medium using an image sensor 52. For example, it is desirable for the liquid ejection device to have the following configuration.

[0084] As shown in FIG. 10A, the first inkjet device 102a has a hardware configuration including an image sensor 52.

[0085] The image sensor 52 generates image data by capturing an image of the transported web 104. Specifically, the image sensor 52 captures an image of the front surface of the web 104 at a preset cycle.

[0086] 10(B) is a diagram showing a typical cycle of capturing images by the image sensor 52. Hereinafter, the image data will be referred to as "first image data IMG1", "second image data IMG2", "third image data IMG3", "fourth image data IMG4", ... in the order in which they were captured.

[0087] After that, the first inkjet device 102a performs a frequency analysis process such as FFT (Fast Fourier Transform) on the image data. Using the result of the frequency analysis process, the first inkjet device 102a calculates the peak of image correlation between the two image data.

[0088] FIG. 10C is a diagram showing an example of a frequency analysis result. Specifically, the first inkjet device 102a generates a "first analysis result F12" based on the first image data IMG1 and the second image data IMG2. Similarly, the first inkjet device 102a generates a "second analysis result F23" based on the second image data IMG2 and the third image data IMG3. Next, the first inkjet device 102a generates a "third analysis result F34" based on the third image data IMG3 and the fourth image data IMG4. A peak is calculated in each analysis result.

[0089] Based on the peaks calculated in this way, the first inkjet device 102a calculates the transport amount. Specifically, by comparing the positions at which the peaks occur, the first inkjet device 102a calculates the displacement of the pattern formed on the surface of the web 104. Based on such a result, the first inkjet device 102a generates a pulse, for example, each time the transport amount reaches a certain amount.

[0090] With this configuration, the first inkjet device 102a can generate signals indicative of displacement, transport speed, or a combination of these, similar to an encoder roller, etc. Furthermore, with a configuration in which the image sensor 52 detects the position of the web 104, the work of preparing slits, etc. in advance for the web 104 can be reduced.

[0091] [Other embodiments] The liquid ejection method described above may be realized, for example, by a program. That is, the liquid ejection method is a method executed by a computer by causing an arithmetic unit, a storage device, an input device, an output device, and a control device to cooperate with each other and operate based on the program. The program may be written into a storage device or a storage medium, etc., and distributed, or distributed via a telecommunication line, etc.

[0092] Each of the devices described above does not have to be a single device, that is, each device may be a system made up of multiple devices.

[0093] The image forming apparatus may be, for example, a commercial printing machine (such as a large electrophotographic printer or an inkjet printer).

[0094] The recording medium is, for example, paper (also called "plain paper"). However, the recording medium may be coated paper other than paper, label paper, overhead projector sheet, film, or flexible thin plate. The recording medium may also be roll paper.

[0095] In other words, the material of the recording medium may be a material to which ink droplets or paint such as toner can adhere, can adhere temporarily, adhere and stick, or adhere and penetrate.

[0096] Specifically, the recording medium may be a recording medium such as paper, film, or cloth, an electronic board, an electronic component such as a piezoelectric element (also referred to as a "piezoelectric member"), a powder layer (also referred to as a "powder layer"), an organ model, or a test cell, etc.

[0097] Thus, the material of the recording medium may be any material to which paint can be attached, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or a combination of these.

[0098] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist of the present invention. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0099] 10 :Period 11: Discharge timing 12: Correction amount 13: Correction amount after change 52: Image sensor 52A: First image sensor 52B: Second image sensor 52C: 3rd image sensor 52D: 4th image sensor 102: Inkjet device 102F1: Transport section 102F2: First detection unit 102F3: Second detection section 102F4: Correction section 102F5:Discharge part 104: Web 105: Transport roller 106: Encoder 210C: C head 210K :K head 210M:M head 210Y: Y head 520: Controller 530: Arithmetic device T1: Update timing T11: 11th timing T12: 12th timing T13: 13th timing T14: 14th timing T2: Second timing [Prior art documents] [Patent documents]

[0100] [Patent Document 1] JP 2019-10751 A

Claims

1. a conveying unit that conveys the recording medium in a conveying direction by using a rotating body; A first detection unit that detects a first detection amount that indicates a rotation amount of the rotating body; a second detection unit that detects a second detection amount indicating a position of the recording medium in the transport direction, a transport speed of the recording medium in the transport direction, or a combination thereof, based on a pattern of the recording medium identified by photographing the recording medium; a correction unit that calculates a second timing by correcting a first timing for ejecting liquid, the first timing being determined by the first detection amount, based on the second detection amount; a discharge unit that discharges the liquid onto the recording medium at the second timing; Equipped with The first detection unit is an encoder that generates a first pulse indicative of the first detection amount; The second timing is The second pulse is calculated by counting a counter value obtained by equally dividing the first pulse in time, The correction unit is In the correction amount for correcting one or more periods of the first pulse, a reference timing that is a reference timing is changed to calculate the second timing. Liquid discharge device.

2. The ejection unit includes a plurality of ejection units arranged from upstream to downstream in the transport direction, and the second detection unit is provided for each of the ejection units; The correction unit is Calculating the second timing based on the correction result for the upstream discharge portion The liquid ejection device according to claim 1 .

3. The second detection unit is Calculating the displacement of the pattern to calculate the fluctuation of the transport speed; Calculating a correction amount to offset the deviation caused by the fluctuation; The correction unit is Calculating the second timing with the correction amount The liquid ejection device according to claim 1 .

4. A liquid ejection method performed by a liquid ejection device, comprising: a conveying step in which the liquid ejection device conveys the recording medium in a conveying direction using a rotating body; a first detection step in which the liquid ejection device detects a first pulse indicating a first detection amount that indicates an amount of rotation of the rotating body; a second detection step in which the liquid ejection device detects a second detection amount indicating a position of the recording medium in the transport direction, a transport speed of the recording medium in the transport direction, or a combination thereof, based on a pattern of the recording medium identified by photographing the recording medium; a first timing calculation step of calculating a first timing at which the liquid ejection device ejects liquid, the first timing being determined by the first detected amount; a correction procedure in which the liquid ejection device calculates the second timing by using a counter value counting a second pulse obtained by equally dividing the first pulse in time, and calculates the second timing by changing a reference timing, which is a timing used as a reference, for a correction amount for correcting one or more periods of the first pulse; a discharge step of discharging the liquid onto the recording medium at the second timing by the liquid discharge device; A liquid ejection method comprising the steps of:

5. A program for causing a computer to execute the liquid ejection method according to claim 4.

Images