Inkjet recording device

Abstract

To extend the service life of an ink jet recording device while maintaining the desired image quality.SOLUTION: An ink jet recording device 1 comprises: a conveyance amount detection unit 15 which detects conveyance amounts of a recording medium 6 and a head 5; a stain amount prediction unit 32 which predicts a stain amount of the conveyance amount detection unit 15 with the combination of a plurality of ink jet drops D used in printing to the recording medium 6 from the head 5; and an encoder adjustment unit 33 which adjusts a control amount of the conveyance amount detection unit 15 from the stain amount predicted by the stain amount prediction unit 32.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Inkjet image forming devices print by ejecting ink from a head onto recording media based on image data, but ink droplets (mist) that do not adhere to the recording media can contaminate the inside of the machine. If these ink droplets adhere to the encoder used to transport the recording media or drive the head, the amount of light incident on the optical sensor that reads the encoder can decrease, causing the sensor to malfunction and leading to machine failure. Machine failure requires a service technician to replace, repair, or clean the encoder, resulting in downtime.

[0003] Patent Document 1 discloses a configuration for predicting the remaining life of an optical encoder by predicting the degree of contamination of the optical encoder by mist from the amount of ink used, with the aim of predicting the timing of failure of the optical encoder.

[0004] Patent Document 2 discloses a method for quantitatively predicting the degree of encoder contamination, taking into account that the amount of mist generated varies depending on the print mode, and predicting when the encoder will reach the end of its life. Furthermore, it also discloses a configuration for informing the user that a print mode selected by the user generates a lot of mist, which may shorten the encoder's life, and a configuration for introducing a print mode that produces the same or similar image quality as the selected print mode but generates less mist. Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional methods described in Patent Document 1 and the like have not been able to solve the problem of extending the life of optical encoders that break down due to mist adhesion.

[0006] In the conventional method described in Patent Document 2 and the like, the user is forced to change the print mode selected in order to extend the life of the encoder, which may affect image quality and productivity.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to extend the life of an inkjet recording apparatus while maintaining a desired image quality. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, an inkjet recording apparatus according to one aspect of the present invention comprises a transport distance detection unit that detects the transport distance of a recording medium and a head, a prediction unit that predicts the amount of contamination on the transport distance detection unit based on a combination of multiple inkjet drops used in printing from the head to the recording medium, and an adjustment unit that adjusts the control amount of the transport distance detection unit based on the amount of contamination predicted by the prediction unit. The conveyance amount detection unit has an encoder and a sensor that reads the movement amount of the encoder, and the adjustment unit adjusts the control amount so as to increase the sensitivity of the light receiving portion of the sensor as the predicted amount of dirt accumulates. . [Effects of the Invention]

[0009] The life of the inkjet recording device can be extended while maintaining the desired image quality. [Brief explanation of the drawings]

[0010] [Figure 1] Block diagram of an inkjet recording apparatus according to an embodiment. [Figure 2] Functional block diagram of an inkjet recording device [Figure 3] Flowchart of soiling amount prediction control [Figure 4] Flowchart of encoder adjustment control based on predicted amount of dirt [Figure 5] A graph showing the relationship between the amount of dirt on the encoder and the threshold value DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] FIG. 1 is a block diagram of the hardware configuration of an inkjet recording apparatus 1 according to an embodiment.

[0013] As shown in Figure 1, print data 2 is input to an inkjet recording device 1. The print data 2 is a data set that includes settings such as print quality. In the inkjet recording device 1, in response to the input of the print data 2, a discharge control signal is output from a CPU 3 to a head 5 based on the state of an internal temperature detection sensor 4 and the settings of a recording medium 6 set inside the device. Based on the discharge control signal, the head 5 performs multiple drops D of ink onto a recording medium 6 such as paper to form an image.

[0014] The CPU 3 is responsible for overall control of the inkjet recording apparatus 1 .

[0015] The temperature detection sensor 4 monitors the temperature inside the inkjet recording apparatus 1. The temperature detection sensor 4 outputs information on the measured temperature inside the apparatus to the CPU 3.

[0016] The head 5 ejects ink onto the recording medium 6 based on an ejection control signal sent from the CPU 3 .

[0017] The encoder 7 is a disk on which a scale 9 for transporting the recording medium 6 is recorded.

[0018] The encoder sensor 8 is provided in the encoder 7 and includes a light-emitting unit 8a and a light-receiving unit 8b. The encoder sensor 8 detects with the light-receiving unit 8b whether the light emitted from the light-emitting unit 8a is blocked or not blocked by the scale 9, and outputs a signal of H or L according to the detection result.

[0019] The scale 9 is provided on the encoder 7 and is printed at equal intervals to block or transmit light emitted from the encoder sensor 8 in order to accurately measure the amount of movement of the recording medium 6.

[0020] The A-phase signal 10a and B-phase signal 10b are signals output from the encoder sensor 8, and the CPU 3 counts these signals to measure the distance the recording medium 6 has moved.

[0021] In this embodiment, elements such as the encoder 7, encoder sensor 8, and scale 9 are collectively referred to as a "transport distance detection unit 15 that detects the transport distance of the recording medium 6 and the head 5." Note that the transport distance detection unit 15 may be any element that is capable of detecting at least the transport distance of the recording medium 6 and the head 5, and may be configured to apply elements other than the encoder 7 and encoder sensor 8.

[0022] The recording medium moving unit 11 is an element that transports the recording medium 6, and includes a motor as a drive source and rollers that transmit the drive force to the recording medium 6. The recording medium moving unit 11 transports the recording medium 6 based on an operation command from the CPU 3.

[0023] The encoder / encoder sensor dirt amount recording unit 12 records the integrated value of the dirt amount on the scale 9 of the encoder 7 and on the light-emitting element 8a and light-receiving element 8b of the encoder sensor 8 based on the discharge control signal. Specifically, the encoder / encoder sensor dirt amount recording unit 12 can be implemented by a storage device such as a memory. Hereinafter, the "encoder / encoder sensor dirt amount recording unit 12" may also be written as the "dirt amount recording unit 12".

[0024] The light amount change unit 13 changes the voltage of the light emitting unit 8a of the encoder sensor 8 in response to a control command from the CPU 3. The light amount change unit 13 changes the input voltage to the light emitting unit 8a, thereby changing the light emission amount.

[0025] The light receiving sensitivity change unit 14 changes the sensitivity of the light receiving unit 8 b of the encoder sensor 8 in response to a control command from the CPU 3 .

[0026] The CPU 3 reads the scale 9 marked on the encoder 7 using the encoder sensor 8, and calculates the amount of movement of the recording medium 6 using the A-phase signal 10a and B-phase signal 10b, and controls the recording medium movement unit 11. The recording medium 6 is moved in a predetermined transport direction by the recording medium movement unit 11.

[0027] Not all of the ink multi-drops D from the head 5 are adsorbed onto the recording medium 6, and the mist M that is not adsorbed onto the recording medium 6 floats around inside the machine.

[0028] If mist M floating inside the machine adheres to the scale 9 of the encoder 7 or to the light-emitting element 8a or light-receiving element 8b of the encoder sensor 8, the amount of light incident on the light-receiving element 8b of the encoder sensor 8 decreases, and as the dirt becomes severe, the encoder 7 will skip readings and the scale 9 will not be read accurately. The transport distance of the recording media 6 is measured by counting the values ​​of the A-phase signal 10a and B-phase signal 10b output from the encoder sensor 8, but if the scale 9 cannot be read accurately, a deviation will occur from the actual transport distance, and ink will be ejected in a location other than the desired printing location. This will require a service technician to clean the scale 9 of the encoder 7 or replace the encoder 7 or encoder sensor 8, resulting in machine downtime.

[0029] In this embodiment, to solve the problem of downtime, the amount of dirt accumulated on the encoder 7 and encoder sensor 8 is recorded by the dirt amount recording unit 12 based on the print data 2, and control is performed to increase the light intensity of the light-emitting element 8a of the encoder sensor 8 or increase the sensitivity of the light-receiving element 8b according to the amount of dirt. This makes it possible to accurately read the scale 9 of the encoder 7 even if dirt occurs inside the machine, and extends the life of the machine.

[0030] Fig. 2 is a functional block diagram of the inkjet recording apparatus 1. In this embodiment, the CPU 3 is configured to be able to execute, as the above-mentioned controls, "stain amount prediction control" to be described later with reference to Fig. 3, and "encoder adjustment control based on the predicted stain amount" to be described later with reference to Fig. 4. As shown in Fig. 2, the CPU 3 has, as functions related to the above-mentioned controls, a print control unit 31, a stain amount prediction unit 32 (prediction unit), and an encoder adjustment unit 33 (adjustment unit).

[0031] The print control unit 31 controls the printing operation of the inkjet recording device 1. Based on the print data 2 input to the CPU 3 and print information (type of recording medium 6, print mode, etc.), the print control unit 31 generates a discharge control signal for printing an image corresponding to the print data 2 on the recording medium 6, and outputs the signal to the head 5. The print control unit 31 also outputs the print information and discharge control information to the dirt amount prediction unit 32.

[0032] The contamination amount prediction unit 32 predicts the amount of contamination on the transport amount detection unit 15 (encoder 7, encoder sensor 8, etc.) based on a combination of multiple inkjet drops D used in printing from the head 5 onto the recording medium 6.

[0033] The dirt amount prediction unit 32 predicts the dirt amount of the transport amount detection unit 15 using a dirt degree coefficient based on a first element related to the way in which the multiple inkjet drops D are ejected and a second element related to the distance between the head 5 that ejects the ink and the recording medium 6.

[0034] In ink ejection control, the configuration of the ink multi-drop D can be changed by the following factors.

[0035] - Size of one dot in print data 2 (large, medium, small, etc.) Print mode (speed, image quality, etc.) 6 types of recording media (plain paper, inkjet paper, postcards, etc.) Cabin temperature

[0036] In this embodiment, taking such configuration changes into consideration, the coefficient based on the first element used to predict the amount of dirt is changed depending on elements including at least one of the density per dot, print mode, type of recording medium 6, and internal temperature. Density information is obtained, for example, from a discharge control signal provided by the print control unit 31. Information on the print mode and type of recording medium 6 is obtained, for example, from print information provided by the print control unit 31. Internal temperature information is obtained, for example, from the temperature detection sensor 4.

[0037] The coefficient of the first element can be set relatively large under conditions such as when the proportion of large droplets is high, when the print mode prioritizes image quality, when the recording media 6 is high quality such as inkjet paper, when the temperature inside the machine is relatively high, etc. Under such conditions, the amount of ink ejection becomes relatively large, and the amount of mist M floating inside the machine also increases relatively, which is thought to result in a relatively large amount of dirt on the encoder 7 and the like.

[0038] On the other hand, the coefficient of the first element can be set relatively small under conditions such as when the proportion of small droplets is high, when the print mode prioritizes speed, when the recording medium 6 is low quality such as plain paper, when the temperature inside the machine is relatively low, etc. Under such conditions, the amount of ink ejected becomes relatively small, and the amount of mist M floating inside the machine also becomes relatively small, so it is thought that the amount of dirt on the encoder 7 and the like also becomes relatively small.

[0039] Furthermore, when recording the amount of dirt on the encoder 7 and scale 9, in addition to the first element described above, the distance between the head 5 and the recording medium 6 (close when printing on plain paper, far when printing on thick paper) is also taken into account to determine the coefficient for recording the amount of dirt. In other words, the coefficient based on the second element used to predict the amount of dirt changes depending on the distance between the head 5 and the recording medium 6. The distance between the head 5 and the recording medium 6 can be calculated based on information about the thickness of the recording medium 6, for example. Information about the thickness of the recording medium 6 is obtained, for example, from the printing information provided by the print control unit 31, similar to the information about the type of recording medium 6 described above.

[0040] The coefficient of the second element can be set relatively large when the type of recording medium 6 is one in which the distance between the head 5 and the recording medium 6 is relatively large. Under such conditions, the proportion of the ink ejected from the head 5 that becomes mist M floating inside the device increases, and it is thought that the amount of dirt on the encoder 7 and the like also increases relatively.

[0041] On the other hand, the coefficient of the second element can be set relatively small when the type of recording medium 6 is one in which the distance between the head 5 and the recording medium 6 is relatively short. Under such conditions, the proportion of the ink ejected from the head 5 that becomes mist M floating inside the device is reduced, and it is thought that the amount of dirt on the encoder 7 and the like is also relatively reduced.

[0042] In other words, the coefficient based on the second element used to predict the amount of dirt does not necessarily increase as the size per dot (amount of ink used) increases.

[0043] The dirt amount prediction unit 32 predicts the dirt amount using the coefficient of the first element and the coefficient of the second element, and outputs the predicted dirt amount to the dirt amount recording unit 12. The dirt amount recording unit 12 accumulates and records the dirt amount information sequentially input from the dirt amount prediction unit 32.

[0044] The encoder adjustment unit 33 adjusts the control amount of the conveyance amount detection unit 15 based on the amount of dirt predicted by the dirt amount prediction unit 32. The encoder adjustment unit 33 determines the degree of dirt on the encoder 7, scale 9, encoder sensor 8, etc. based on the integrated value of the amount of dirt recorded in the dirt amount recording unit 12. When the current amount of dirt on the encoder 7, etc. is so great that it affects measurement accuracy, the encoder adjustment unit 33 adjusts the control amount so as to ensure measurement accuracy.

[0045] Specifically, the amount of dirt on the encoder 7, etc. is accumulated, and depending on the amount of dirt, (1) Increasing the light emission amount of the light emitting part 8a of the encoder sensor 8; (2) Increasing the sensitivity of the light receiving portion 8b of the encoder sensor 8; In the case of the control (1) above, the encoder adjuster 33 increases the amount of control given to the light amount changer 13. In the case of the control (2) above, the encoder adjuster 33 increases the amount of control given to the light sensitivity changer 14.

[0046] By performing this type of control, even if the encoder 7 and encoder sensor 8 become dirty with mist M, a constant amount of light can be sent from the light-emitting part 8a of the encoder sensor 8 to the light-receiving part 8b, allowing the encoder sensor 8 to accurately read the scale 9 on the encoder 7, thereby extending the lifespan of the machine compared to conventional machines.

[0047] FIG. 3 is a flowchart of the dirt amount prediction control.

[0048] In step S11, the print control unit 31 checks whether print data 2 has been input to the inkjet recording device 1. If print data 2 has been input (Yes in S11), the process proceeds to step S12. If print data 2 has not been input, the process waits.

[0049] In step S12, the print control unit 31 calculates the type of multi-drop D to be ejected and the number of droplets of each type based on the input print data 2 and print mode (speed-oriented, quality-oriented, etc.). At this time, the number of blank ejections to be performed before, during, and after printing is also confirmed.

[0050] In step S13, the print control unit 31 executes a print animation according to the input print data 2 and print mode. The print control unit 31 outputs to the head 5 a discharge control signal for discharging the type and number of droplets of multi-drop D calculated in step S12 from the head 5. The head 5 discharges ink onto the recording medium 6 based on the received discharge control signal. In this step, the print control unit 31 also outputs the discharge control signal and printing information (print mode, type of recording medium 6, etc.) to the dirt amount prediction unit 32.

[0051] In step S14, the contamination amount prediction unit 32 calculates the contamination amount of the conveyance distance detection unit 15 (encoder 7, encoder sensor 8, etc.) based on the type of ejected multi-drops D, the number of ejected drops, etc. As described above, the contamination amount prediction unit 32 calculates the contamination amount using a contamination degree coefficient based on a first element related to the ejection method of the multiple inkjet drops D and a second element related to the distance between the head 5 that ejects the ink and the recording medium 6. This allows the contamination amount to be calculated not just based on the amount of ink consumed, but also taking into account various printing conditions such as the type of multi-drops D used, so the contamination amount of the conveyance distance detection unit 15 can be predicted with higher accuracy.

[0052] In step S15, the dirt amount calculated by the dirt amount prediction unit 32 is added to the accumulated encoder dirt amount (accumulated dirt amount value) recorded in the dirt amount recording unit 12.

[0053] FIG. 4 is a flowchart of the encoder adjustment control based on the predicted amount of dirt.

[0054] In step S21, the print control unit 31 acquires the accumulated encoder dirt amount (accumulated dirt amount value) before printing currently recorded in the dirt amount recording unit 12 when the inkjet recording device 1 is turned on or before the printing operation starts.

[0055] In step S22, the print control unit 31 executes the printing operation described with reference to the flowchart in Fig. 3. In conjunction with this, the dirt amount prediction control in Fig. 3 is also executed, and the dirt amount integrated value is updated to the latest information after the current printing operation.

[0056] In step S23, after printing, the encoder adjustment unit 33 determines whether the accumulated amount of dirt on the encoder has reached a predetermined threshold. If the amount of dirt has reached the threshold (Yes in S23), the process proceeds to step S24; if not (No in S23), the process returns to step S21.

[0057] In step S24, the amount of dirt has accumulated up to the threshold value, and in order to prevent malfunction due to dirt on the encoder 7, the encoder adjustment unit 33 adjusts the control amount to increase the light intensity of the light-emitting element 8a of the encoder sensor 8 or to increase the sensitivity of the light-receiving element 8b of the encoder sensor 8. After completing the processing of step S24, the process returns to step S21.

[0058] In the processing of step S24, the encoder adjustment unit 33 may perform either one of the following controls, increasing the light intensity of the light-emitting unit 8a or increasing the sensitivity of the light-receiving unit 8b, depending on the degree of dirt, or may perform both.

[0059] Fig. 5 is a diagram showing the relationship between the amount of dirt on the encoder and the threshold value. The horizontal axis of Fig. 5 represents the number of prints, and the vertical axis represents the amount of dirt on the encoder. Fig. 5 plots the integrated value of the amount of dirt on the encoder for each number of prints.

[0060] As shown in Figure 5, the amount of dirt on the encoder is not directly proportional to the number of prints or the amount of ink used. The accumulated value of the amount of dirt tends to fluctuate depending on factors such as the type of multidrop D used in each print. Therefore, in this embodiment, as explained with reference to Figure 3, the coefficient used to predict the amount of dirt during each print is varied depending on the conditions of the print. By updating the accumulated value based on the predicted amount of dirt in this way, the estimation accuracy of the accumulated value of the amount of dirt is improved, making it possible to predict the actual degree of dirt more accurately.

[0061] Furthermore, in this embodiment, a configuration may be adopted in which multiple thresholds (three thresholds 1, 2, and 3 in the example of FIG. 5) are applied as the thresholds used in step S23 of FIG. 4, as shown in FIG. 5. For example, the thresholds 1, 2, and 3 are set to successively larger values ​​in this order. In this case, when the amount of dirt on the encoder reaches a predetermined threshold 1, measures are taken to prevent malfunction by increasing the light intensity of the light-emitting element 8a of the encoder sensor 8 or increasing the sensitivity of the light-receiving element 8b of the encoder sensor 8.

[0062] Next, when the dirt on the encoder 7 increases further and the amount of encoder dirt reaches threshold 2, which is greater than threshold 1, the light intensity of the light-emitting element 8a of the encoder sensor 8 is increased further than that of threshold 1, or the sensitivity of the light-receiving element 8b of the encoder sensor 8 is increased further than that of threshold 1.

[0063] Furthermore, when the amount of encoder dirt reaches threshold 3, which is greater than threshold 2, the light intensity of the light-emitting element 8a of the encoder sensor 8 is increased further than that of threshold 2, or the sensitivity of the light-receiving element 8b of the encoder sensor 8 is increased further than that of threshold 2.

[0064] In this way, by setting multiple thresholds and adjusting the control amount of the encoder 7 in stages, it is possible to set a more appropriate control amount according to the amount of dirt on the encoder, allowing for more fine-tuned adjustments, thereby further extending the life of the inkjet recording device.

[0065] The inkjet recording device 1 of this embodiment comprises a transport amount detection unit 15 that detects the transport amount of the recording medium 6 and the head 5, a dirt amount prediction unit 32 that predicts the amount of dirt on the transport amount detection unit 15 based on a combination of multiple inkjet drops D used for printing from the head 5 to the recording medium 6, and an encoder adjustment unit 33 that adjusts the control amount of the transport amount detection unit 15 based on the amount of dirt predicted by the dirt amount prediction unit 32.

[0066] This configuration eliminates the need for processes such as changing the print mode selected by the user to extend the life of the encoder 7, even when the amount of contamination on the conveyance distance detection unit 15, such as the encoder 7, increases. This prevents any impact on image quality or productivity. In this embodiment, instead of the process described in Patent Document 2, a process is performed to adjust the control amount of the conveyance distance detection unit 15 based on the predicted amount of contamination. This allows printing to be performed with the user's desired settings while extending the life of elements of the inkjet recording device 1, such as the encoder 7. Furthermore, even if the conveyance distance detection unit 15, such as the optical encoder 7, becomes contaminated by mist M that is ejected from the head 5 but does not land on the recording medium 6, malfunctions can be suppressed by adjusting the control amount. Therefore, this embodiment allows the life of the inkjet recording device 1 to be extended while maintaining the desired image quality.

[0067] Furthermore, in the inkjet recording apparatus 1 according to this embodiment, the dirt amount prediction unit 32 predicts the dirt amount of the conveyance distance detection unit 15 using a dirt level coefficient based on a first element relating to the ejection method of the inkjet drops D and a second element relating to the distance between the head 5 ejecting the ink and the recording medium 6. The coefficient based on the first element is changed by elements including at least one of the density per dot, the print mode, the type of recording medium 6, and the temperature inside the device, while the coefficient based on the second element is changed by the distance between the head 5 ejecting the ink and the recording medium 6.

[0068] With this configuration, the amount of dirt accumulating in the encoder 7 can be weighted not simply by the amount of ink used, but by the type of inkjet drops D that are combined, making it possible to predict the degree of dirt more accurately than simply by the amount of ink used.

[0069] The prediction method used by the stain amount prediction unit 32 is not limited to calculations using formulas or the like that use the above-mentioned variable coefficients. For example, instead of simply calculating the amount of ink used, a prediction table may be created that takes into account various conditions, similar to the above-mentioned coefficients, and the stain amount may be predicted each time printing is performed by referring to this prediction table based on the printing conditions.

[0070] Furthermore, in the inkjet recording device 1 according to this embodiment, the encoder adjustment unit 33 adjusts the amount of control given to the light amount change unit 13 so as to increase the light amount of the light emitting element 8a of the encoder sensor 8 of the conveyance amount detection unit 15 as the amount of dirt predicted by the dirt amount prediction unit 32 accumulates.

[0071] As dirt accumulates on the encoder 7, the amount of light transmitted through the encoder scale 9 decreases, and the amount of light that enters the light-receiving portion 8b of the encoder sensor 8 becomes less than when there is no dirt. If the amount of incident light decreases, the light-receiving portion 8b of the encoder sensor will no longer be able to react, which may result in the recording media 6 not being transported accurately. For this reason, the above configuration increases the amount of light used to read the encoder 7 according to the amount of accumulated dirt, making it possible to transport the recording media 6 accurately even with a dirty encoder 7.

[0072] Furthermore, in the inkjet recording device 1 according to this embodiment, the encoder adjustment unit 33 adjusts the control amount to the light receiving sensitivity change unit 14 so as to increase the sensitivity of the light receiving unit 8b of the encoder sensor 8 of the conveyance amount detection unit 15 as the amount of dirt predicted by the dirt amount prediction unit 32 accumulates.

[0073] As dirt accumulates on the encoder 7, the amount of light transmitted through the encoder scale 9 decreases, and the amount of light entering the light-receiving element 8b of the encoder sensor 8 becomes less than when there is no dirt. This reduced amount of incident light may prevent the light-receiving element 8b of the encoder sensor 8 from responding, making it impossible to accurately transport the recording media 6. The light-receiving element 8b of the encoder sensor 8 changes its internal voltage level depending on the amount of incident light, but the internal voltage level changes differently even with the same amount of light depending on the sensitivity setting of the sensor's light-receiving element. Therefore, with the above configuration, even if the amount of light entering the light-receiving element 8b of the encoder sensor 8 decreases depending on the amount of accumulated dirt, by changing the light-receiving sensitivity so that the change in the internal voltage level remains the same, accurate transport of the recording media 6 is possible even with a dirty encoder 7.

[0074] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0075] 1. Inkjet recording device 5 heads 6. Recording media 7 Encoders 8 Encoder Sensor 8a Light-emitting part 8b Light receiving section 15 Conveyance amount detection unit 32 Dirt amount prediction unit (prediction unit) 33 Encoder adjustment unit (adjustment unit) [Prior art documents] [Patent documents]

[0076] [Patent Document 1] Patent No. 5305009 [Patent Document 2] Japanese Patent Application Publication No. 2017-013263

Claims

1. a transport distance detection unit that detects the transport distance of the recording medium and the head; a prediction unit that predicts the amount of dirt on the conveyance distance detection unit based on a combination of a plurality of inkjet drops used in printing from the head onto the recording medium; an adjustment unit that adjusts a control amount of the conveyance amount detection unit based on the dirt amount predicted by the prediction unit, the transport amount detection unit includes an encoder and a sensor that reads the amount of movement of the encoder; the adjustment unit adjusts the control amount so as to increase the sensitivity of the light receiving unit of the sensor as the predicted amount of dirt accumulates. Inkjet recording device.

2. the prediction unit predicts the amount of dirt on the conveyance distance detection unit using a coefficient of a degree of dirt based on a first element relating to a method of ejecting the inkjet drops and a second element relating to a distance between the head that ejects the ink and the recording medium, the coefficient based on the first element is changed by an element including at least one of a density per dot, a print mode, a type of the recording medium, and an internal temperature of the printer; the coefficient based on the second element is changed depending on the distance between the head that ejects ink and the recording medium; The inkjet recording apparatus according to claim 1 .

3. The adjustment unit adjusts the control amount so as to increase the light intensity of the light-emitting unit of the sensor as the predicted amount of dirt accumulates. The inkjet recording apparatus according to claim 1 .

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