Transport device, image forming apparatus, transport method, and program

Abstract

To provide a conveyance device, an image forming device, a conveyance method, and a program that can secure a targeted conveyance amount even if the roll diameter of a roll medium changes.SOLUTION: A conveyance device includes: a paper feeding section for feeding a recording medium from a roll medium; a conveyance roller for conveying the recording medium; an acquisition section for acquiring an actual conveyance amount, which is the actual conveyance amount of the recording medium conveyed by the conveyance roller; a first calculation section for calculating an adjustment value for an ideal conveyance amount based on the difference between the ideal conveyance amount and the actual conveyance amount acquired by the acquisition section; a second calculation section for calculating an approximation line for an adjustment point determined by the adjustment value calculated by the first calculation section and the roll diameter of the roll medium when the recording medium is conveyed by the actual conveying amount in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll medium; and a correction section for specifying the adjustment value corresponding to the roll diameter of the roll medium from the approximation line and correcting the conveyance amount by the conveyance roller according to the adjustment value.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a conveying device, an image forming apparatus, a conveying method, and a program.

Background Art

[0002] There are already known a conveying device and an image forming apparatus that apply back tension to a roll medium on the paper feeding side and convey the medium to a printing unit by a conveying roller for printing.

[0003] As a technique related to the conveyance of such a roll medium, there are provided a platen that supports a sheet-like recording medium conveyed forward during printing, a take-up shaft around which the recording medium after printing is taken up, a tension bar that applies tension to the recording medium by pressing a portion between the platen and the take-up shaft of the recording medium, a support arm that supports the tension bar, a support shaft that supports the support arm swingably, and a spring that applies a force in a direction of swinging upward with respect to the support arm. A printer is disclosed in which, when viewed in the axial direction of the support shaft, the center of the support shaft is located inside the contour of the take-up shaft (for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, in order to apply a certain torque, for example, when a torque limiter is attached to the paper feed roll shaft, there is a problem that the back tension changes due to the change in the remaining roll diameter, and the conveyance amount deviates from the target conveyance amount. Also, a method of correcting the conveyance amount by a correction table according to the roll diameter can be considered, but it is difficult to cope with a wide variety of media types and brands, and there are also differences in each machine body. Therefore, even if the conveyance amount is corrected by the correction table, the conveyance amount often deviates from the target conveyance amount. Further, as in the technique described in Patent Document 1, when a tension bar or the like is provided to make the back tension constant regardless of the roll diameter, there is also a problem that the configuration and the control of the paper feeding operation linked to the tension bar become complicated.

[0005] The present invention has been made in view of the above, and aims to provide a conveying device, an image forming device, a conveying method, and a program that can ensure the desired conveying amount even when the roll diameter of the roll media changes. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the present invention comprises: a paper feeding unit for feeding a recording medium from a roll media; a transport roller for transporting the recording medium; an acquisition unit for acquiring the actual transport amount, which is the actual amount of the recording medium transported by the transport roller; a first calculation unit for calculating an adjustment value for the ideal transport amount based on the difference between the ideal transport amount and the actual transport amount acquired by the acquisition unit; a second calculation unit for calculating an approximation line for an adjustment point determined by the adjustment value calculated by the first calculation unit and the roll diameter of the roll media when the recording medium is transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media; and a correction unit for identifying an adjustment value corresponding to the roll diameter of the roll media from the approximation line and correcting the transport amount by the transport roller using the adjustment value. The first calculation unit stores the type of roll media, the calculated adjustment value, and the roll diameter of the roll media in a storage unit, and the second calculation unit refers to the storage unit and calculates the approximation line for the adjustment point determined by the adjustment value and roll diameter corresponding to the type of roll media in use. It is characterized by the following: [Effects of the Invention]

[0007] According to the present invention, even if the roll diameter of the roll media changes, the desired conveying volume can be ensured. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an external perspective view of an image forming apparatus according to an embodiment. [Figure 2] Figure 2 shows an example of the main components of an image forming apparatus according to an embodiment. [Figure 3] Figure 3 is a side cross-sectional view of an image forming apparatus according to an embodiment. [Figure 4]Figure 4 shows an example of the configuration of the drive mechanism for the transport roller of the image forming apparatus according to the embodiment. [Figure 5] Figure 5 shows an example of the hardware configuration of an image forming apparatus according to an embodiment. [Figure 6] Figure 6 shows an example of the configuration of a functional block in the control unit of an image forming apparatus according to an embodiment. [Figure 7] Figure 7 shows an example of an approximation line for the adjustment values ​​calculated over two transport cycles. [Figure 8] Figure 8 shows an example of an approximation line for the adjustment values ​​calculated over three transport cycles. [Figure 9] Figure 9 is a flowchart showing an example of the operation flow for correcting the transport amount of the recording medium in the image forming apparatus according to the embodiment. [Figure 10] Figure 10 shows an example of an approximation curve for adjustment values ​​used in an image forming apparatus according to modified embodiment 1. [Figure 11] Figure 11 shows an example of an approximation line calculated by excluding outliers, used in an image forming apparatus according to a modified example 2 of the embodiment. [Figure 12] Figure 12 shows an example of an approximation line calculated taking abnormal values ​​into account, used in the image forming apparatus according to the modified embodiment 3. [Figure 13] Figure 13 shows an example of an approximation line calculated using the most recent adjustment value, used in the image forming apparatus according to the modified embodiment 4. [Figure 14] Figure 14 shows an example of the configuration of the functional block of the control unit of the image forming apparatus according to modified embodiment 5. [Figure 15] Figure 15 shows an example of an approximation line calculated in response to temperature, used in an image forming apparatus according to modified embodiment 5. [Figure 16] Figure 16 shows an example of a straight line in a correction formula composed of representative values, used in an image forming apparatus according to modified embodiment 6. [Modes for carrying out the invention]

[0009] The following describes in detail embodiments of the transport apparatus, image forming apparatus, transport method, and program according to the present invention with reference to the drawings. Furthermore, the present invention is not limited by the following embodiments, and the components in the following embodiments include those easily conceivable by those skilled in the art, those substantially identical, and those within the so-called equivalent range. Moreover, various omissions, substitutions, modifications, and combinations of components can be made without departing from the spirit of the following embodiments.

[0010] Furthermore, computer software refers to programs related to the operation of a computer, and other information used for computer processing that is similar to a program (hereinafter, computer software is referred to as "software"). Application software is a general term for software used to perform specific tasks, within the classification of software. On the other hand, an operating system (OS) is software that controls the computer and enables application software and other programs to utilize computer resources. The operating system performs basic management and control of the computer, such as input / output control, management of hardware such as memory and hard disks, and process management. Application software operates by utilizing the functions provided by the operating system. A program is a set of instructions for a computer, combined to produce a specific result. Furthermore, something similar to a program refers to something that is not a direct instruction to the computer and therefore cannot be called a program, but has similar properties to a program in that it defines the processing of the computer. For example, a data structure (the logical structure of data, represented by the interrelationships between data elements) falls under the category of something similar to a program.

[0011] (Overall configuration of the image forming apparatus) FIG. 1 is an external perspective view of an image forming apparatus according to an embodiment. FIG. 2 is a diagram showing an example of a main configuration of the image forming apparatus according to the embodiment. FIG. 3 is a side sectional view of the image forming apparatus according to the embodiment. With reference to FIGS. 1 to 3, the overall configuration of the image forming apparatus 1 according to the present embodiment will be described.

[0012] The image forming apparatus 1 according to the present embodiment is a wide-width serial type inkjet recording apparatus. As shown in FIGS. 1 and 2, the image forming apparatus 1 includes a device main body 30, a support base 31 that supports the device main body 30, and a control unit 100.

[0013] As shown in FIGS. 1 and 2, the device main body 30 includes a cover 2, guide rods 3, sub-guide rails 4, a carriage 5, recording heads 6k, 6c, 6m, 6y (printing units), a cartridge loading unit 7, a main scanning motor 8, a drive pulley 9, a pressure pulley 10, a timing belt 11, an encoder 13, an encoder sheet 14, a maintenance mechanism 15, a platen 16, an end detection sensor 20, and a roll media 41.

[0014] The cover 2 is a cover for shielding the image forming portion by the scanning of the carriage 5 from the outside. The guide rods 3 and the sub-guide rails 4 are guide members that are spanned across both side plates of the device main body 30 and hold the carriage 5 slidably in the main scanning direction (direction A shown in FIGS. 1 and 2).

[0015] The carriage 5 is a member that moves in the main scanning direction by a main scanning mechanism unit. Specifically, the carriage 5 moves in the main scanning direction via a timing belt 11 that is rotationally driven by a main scanning motor 8. Further, the carriage 5 mounts a sub-tank for supplying ink of each color to the recording heads 6k, 6c, 6m, 6y shown in FIG. 2.

[0016] The recording heads 6k, 6c, 6m, and 6y are liquid ejection heads mounted on the carriage 5 that form an image by ejecting ink of each color, such as black (K), yellow (Y), magenta (M), and cyan (C), from a nozzle row toward the recording medium P, according to the ink cartridges installed in the cartridge loading section 7. When referring to any of the recording heads 6k, 6c, 6m, and 6y, or collectively, they will simply be referred to as "recording head 6". The recording head 6 has multiple nozzle rows arranged in the sub-scanning direction (direction B shown in Figures 1 and 2). Here, the sub-scanning direction is the direction in which the recording medium P supplied from the roll media 41 is transported (direction B shown in Figures 1 and 2), and is perpendicular to the main scanning direction. The liquid recording head 6 is installed on the carriage 5 such that the ink ejection direction from the nozzle row is downward (towards the recording medium P).

[0017] The cartridge loading section 7 is a loading section that allows for the detachable installation of ink cartridges of each color. The ink filled in the ink cartridges is supplied to the sub-tanks of the carriage 5 via supply tubes of each color by a supply pump unit (not shown).

[0018] The main scanning motor 8 is located on one side of the main scanning direction and rotates the timing belt 11 via the drive pulley 9. The drive pulley 9 is a pulley through which the timing belt 11 is stretched between the drive pulley 9 and the pressure pulley 10, and is rotationally driven by the main scanning motor 8. The pressure pulley 10 is located on the other side of the main scanning direction and through which the timing belt 11 is stretched between the drive pulley 9 and the pressure pulley 10. The pressure pulley 10 is tensioned outward (away from the drive pulley 9) by a tension spring. The timing belt 11 is a traction member stretched between the drive pulley 9 and the pressure pulley 10 and rotates due to the rotational drive of the main scanning motor 8.

[0019] The encoder 13 is mounted inside the carriage 5 and is a sensor that detects the position of the carriage 5 in the main scanning direction by continuously reading the encoder sheet 14 which is stretched across both sides of the main body 30 of the device. The encoder sheet 14 is a sheet that is stretched across both sides of the main body 30 and has slits or the like formed on it that can be read by the encoder 13.

[0020] The maintenance mechanism 15 is a mechanism for maintaining and restoring the state of the recording head 6, mounted in the non-printing area on one side of the carriage 5 in the main scanning direction. The maintenance mechanism 15 includes a cap for capping each nozzle surface of the recording head 6 and a wiping unit for wiping the nozzle surfaces. A replaceable waste liquid tank for collecting waste liquid generated by the maintenance and restoration operation is provided below the maintenance mechanism 15.

[0021] The platen 16 is a component for suction-supporting the recording medium P supplied from the roll media 41.

[0022] The end detection sensor 20 is a sensor that detects the end of the recording medium P supplied from the roll media 41 and transported on the platen 16. By detecting the position of the end of the recording medium P with the end detection sensor 20, it is possible to detect whether or not skew has occurred in the recording medium P.

[0023] The roll media 41 is a roll-shaped medium supplied to the main body 30 as a recording medium P, with torque applied by a paper feed drive unit 32, which will be described later, installed on the support base 31.

[0024] The control unit 100 is a controller that controls the operation of the image forming apparatus 1.

[0025] Furthermore, as shown in Figure 3, the image forming apparatus 1 includes a paper feed drive unit 32 (paper feed unit), a pre-guide plate 16a, a transport roller 17, a pinch roller 18, a post-guide plate 16b, a winding drive unit 33, and a winding paper tube 42.

[0026] The paper feed drive unit 32 is a drive mechanism that rotates the roll media 41 to supply it to the device body 30 as a recording medium P. The paper feed drive unit 32 is driven by a motor and rotates in a direction that eliminates slack while applying a constant torque with a torque limiter or the like.

[0027] The pre-guide plate 16a is a plate member that forms a transport path for the recording medium P, and is installed on the upstream side of the transport direction of the recording medium P relative to the platen 16.

[0028] The transport roller 17 is a roller that intermittently transports the recording medium P on the platen 16 in the sub-scanning direction. The pinch roller 18 is a roller that grips the recording medium P between itself and the transport roller 17.

[0029] The post guide plate 16b is a plate member that forms the transport path for the recording medium P, and is installed downstream of the platen 16 in the transport direction of the recording medium P. The post guide plate 16b is also shaped to guide the transported recording medium P to the winding paper tube 42.

[0030] The winding drive unit 33 is a drive mechanism for winding the recording medium P by supporting the winding paper tube 42 and rotating the winding paper tube 42. The winding drive unit 33 is driven by a motor and rotates in a direction that eliminates slack while applying a constant torque with a torque limiter or the like.

[0031] (Configuration of the drive mechanism for the conveyor rollers) Figure 4 shows an example of the configuration of the drive mechanism for the transport roller of the image forming apparatus according to this embodiment. The configuration of the drive mechanism for the transport roller 17 of the image forming apparatus 1 according to this embodiment will be described with reference to Figure 4.

[0032] As shown in Figure 4, the image forming apparatus 1 includes a transport motor 51, a drive pulley 52, a belt 53, a driven pulley 54, an encoder seat 55, and an encoder 56 as a drive mechanism for controlling the rotation of the transport roller 17.

[0033] The transport motor 51 is a motor that rotates the belt 53 via a drive pulley 52. ​​The transport motor 51 is controlled by the control unit 100. The drive pulley 52 is a pulley on which the belt 53 is stretched between it and a driven pulley 54, and is rotationally driven by the transport motor 51. The belt 53 is a traction member stretched between the drive pulley 52 and the driven pulley 54, and rotates due to the rotational drive of the transport motor 51. The driven pulley 54 is a pulley on which the belt 53 is stretched between it and the drive pulley 52, and rotates due to the rotational drive of the drive pulley 52. ​​The transport roller 17 rotates in conjunction with the rotation of this driven pulley 54, allowing the recording medium P to be intermittently transported in the sub-scanning direction.

[0034] The encoder 56 is a sensor installed at the circumferential end of a disc-shaped encoder sheet 55, which is mounted coaxially with the transport roller 17. By continuously reading the encoder sheet 55, the encoder 56 detects the rotational position and amount of rotation of the transport roller 17. In other words, the amount of recording medium P transported by the rotation of the transport roller 17 is converted into the number of encoder pulses detected by the encoder 56. The detection information read by the encoder 56 is input to the control unit 100. The encoder sheet 55 is a disc-shaped sheet mounted coaxially with the transport roller 17, and has slits or the like formed on its circumferential portion that can be read by the encoder 56.

[0035] As described above, the amount of recording medium P transported is converted into the number of encoder pulses by detection by the encoder 56. If there is a difference (deviation) between the ideal amount of transported recording medium P, i.e., the target amount of transported recording medium P (hereinafter referred to as the target amount of transported recording medium P), it is necessary to correct the amount of transported recording medium P by the transport roller 17 so that the actual amount of transported recording medium P approaches the target amount of transported recording medium P. Also, since the deviation of the transport amount varies depending on the media, it is necessary to print a test pattern for adjusting the transport amount and calculate the adjustment value when changing media. One method of adjusting the transport amount is to print a line upstream of the head, then transport the recording medium, output a test pattern downstream of the head such that the printed line overlaps if the transport amount is correct, and detect the deviation with a sensor. Another method is to print a line upstream of the head, then transport the recording medium, output multiple test patterns downstream of the head such that the printed line overlaps if the transport amount is correct, while shifting the transport amount, and select the point where there is no deviation by visual inspection to make the adjustment. Furthermore, if the torque applied to the roll media 41 by the paper feed drive unit 32 is constant, when the diameter of the roll media 41 decreases, the back tension increases, causing slippage between the transport roller 17 and the recording medium P, resulting in a smaller actual transport volume. Therefore, as an adjustment result for the transport volume, a positive adjustment to the transport volume becomes necessary. In other words, even if the transport volume is adjusted, the transport volume will shift if the remaining amount of media changes.

[0036] Therefore, in this embodiment, the roll diameter of the roll media 41 and the adjustment value when adjusted for the transport amount are stored, an approximation line is created using data from multiple adjustments, and the adjustment value is changed and applied according to the roll diameter that changes during printing, thereby ensuring a stable transport amount that is not affected by the remaining amount of roll media 41. Furthermore, if the same type of media is used, the transport amount can be corrected by identifying and applying an adjustment value corresponding to the roll diameter from the approximation line, without having to perform any further adjustments after the media is replaced. Here, transport amount adjustment refers to calculating an adjustment value for each roll diameter, and further, calculating an approximation line when multiple adjustment values ​​are calculated. Transport amount correction refers to identifying an adjustment value corresponding to the roll diameter during transport of the recording medium P from the approximation line, adding the identified adjustment value to the target transport amount (ideal transport amount), and determining the transport amount to be commanded to the transport roller 17 (hereinafter sometimes referred to as the corrected transport amount).

[0037] (Hardware configuration of image forming apparatus) Figure 5 shows an example of the hardware configuration of the image forming apparatus according to this embodiment. The hardware configuration of the image forming apparatus 1 according to this embodiment will be described with reference to Figure 5.

[0038] As shown in Figure 5, the image forming apparatus 1 includes a control unit 100, an operation panel 120, an edge detection sensor 20, an encoder 13, an encoder 56, a head driver 140, a main scanning motor 8, and a transport motor 51.

[0039] The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an NVRAM (Non-Volatile RAM) 104, an ASIC (Application Specific Integrated Circuit) 105, a print control unit 106, a motor drive unit 107, an I / O 108, and a host I / F 109.

[0040] The CPU 101 is an arithmetic unit that controls the entire image forming apparatus 1. The ROM 102 is a non-volatile memory device that stores fixed data such as programs executed by the CPU 101. The RAM 103 is a volatile memory device that serves as the work area for arithmetic processing by the CPU 101. The RAM 103 also temporarily stores image data and other data.

[0041] NVRAM104 is a non-volatile memory device that retains data even when the power supply to the image forming apparatus 1 is cut off. For example, NVRAM104 stores data for approximation lines used to correct the transport amount, which will be described later.

[0042] ASIC105 is an integrated circuit that processes various signal processing and sorting operations on image data, as well as input / output signals for controlling the entire image forming apparatus 1.

[0043] The print control unit 106 is a control circuit that controls the ejection operation of the recording head 6 via the head driver 140. The print control unit 106 transfers data for driving the recording head 6 to the head driver 140. For example, the print control unit 106 transfers image data as serial data and outputs a transfer clock, latch signal, control signal, etc., required for transferring the image data to the head driver 140. Based on the image data corresponding to one line of the recording head 6 input serially, the head driver 140 selectively supplies drive pulses that constitute the drive waveform received from the print control unit 106 to the pressure generating means of the recording head 6, thereby driving the recording head 6 and ejecting ink. By selecting some or all of the pulses that constitute the drive waveform, or some or all of the waveform elements that form the pulses, it is possible to print dots of different sizes, such as large, medium, and small droplets.

[0044] The motor drive unit 107 is a drive circuit that controls the operation of the main scanning motor 8 and the transport motor 51. The main scanning motor 8 moves the carriage 5 in the main scanning direction according to the control of the motor drive unit 107. The transport motor 51 rotates the transport roller 17 to transport the recording medium P in the sub-scanning direction according to the control of the motor drive unit 107.

[0045] I / O108 is an interface circuit for receiving information detected by various sensors, such as the end detection sensor 20, encoder 13, and encoder 56.

[0046] The host I / F 109 is an interface circuit that transmits and receives data and signals between the host 170, which is an information processing device such as a client PC (Personal Computer), an image reading device, or an imaging device. Specifically, the host I / F 109 transmits and receives data and signals from the host 170 via cable or network. The print data stored in the host I / F 109's receive buffer is analyzed by the CPU 101, image processing and data rearrangement are performed by the ASIC 105, and the print control unit 106 transfers it to the head driver 140 as ejection data.

[0047] The control panel 120 is a device for inputting and outputting various types of information.

[0048] Note that the hardware configuration of the image forming apparatus 1 shown in Figure 5 is an example, and it is not necessary to include all of the components shown in Figure 5, or other components may be included.

[0049] (Configuration and operation of the functional block of the control unit of the image forming apparatus) Figure 6 shows an example of the configuration of the functional block of the control unit of the image forming apparatus according to this embodiment. Figure 7 shows an example of an approximation line for the adjustment value calculated in two transports. Figure 8 shows an example of an approximation line for the adjustment value calculated in three transports. Referring to Figures 6 to 8, the configuration and operation of the functional block of the control unit 100 of the image forming apparatus 1 according to this embodiment will be described.

[0050] As shown in Figure 6, the control unit 100 of the image forming apparatus 1 includes a transport amount acquisition unit 201 (acquisition unit), an adjustment value calculation unit 202 (first calculation unit), an approximation line calculation unit 203 (second calculation unit), a discharge control unit 204, a transport control unit 205 (an example of a correction unit), and a storage unit 206.

[0051] The transport amount acquisition unit 201 is a functional unit that acquires the transport amount (actual transport amount) of the recording medium P transported in the sub-scanning direction by the transport control unit 205's control of the transport motor 51, via I / O 108 from the encoder 56. Specifically, the transport amount acquisition unit 201 receives the number of encoder pulses detected by the encoder 56 via I / O 108 and acquires the transport amount by converting the number of encoder pulses into a transport amount. The transport amount acquisition unit 201 also acquires, for example, the transport amount (actual transport amount) of the recording medium P that is intermittently transported in the sub-scanning direction by the transport control unit 205. The transport amount acquisition unit 201 may acquire each transport amount of the intermittently transported recording medium P, or it may acquire the average value of each intermittent transport amount performed to form one image on the recording medium P.

[0052] The adjustment value calculation unit 202 is a functional unit that calculates an adjustment value for the target transport amount based on the difference between the target transport amount (ideal transport amount) and the actual transport amount obtained by the transport amount acquisition unit 201. For example, the adjustment value calculation unit 202 may calculate the adjustment value by the difference between the target transport amount and the actual transport amount, or it may add this difference to the adjustment value used to correct the transport amount in the previous instance and calculate a new adjustment value. The adjustment value calculation unit 202 then stores the calculated adjustment value in the storage unit 206, associating it with the roll diameter of the roll media 41 at the time of transport of the recording medium P and the type of recording medium P (e.g., brand name). The type of recording medium P is a concept that distinguishes at least one of the following aspects of the recording medium P: material, width, thickness, etc. Also, for example, in the case of an image forming apparatus 1 that uses a single type of recording medium P, it is not necessary to associate the adjustment value and roll diameter with that type.

[0053] The approximation line calculation unit 203 is a functional unit that, by referring to the storage unit 206, calculates an approximation line for a point on a two-dimensional coordinate plane (hereinafter sometimes referred to as an adjustment point) determined by the adjustment value calculated by the adjustment value calculation unit 202 and the roll diameter corresponding to the adjustment value, for the type of recording medium P being used. Here, the two-dimensional coordinate plane is, for example, a coordinate plane determined by the roll diameter as the horizontal axis and the adjustment value as the vertical axis, as shown in Figure 7. Furthermore, calculating an approximation line is synonymous with calculating the coefficients (slope and intercept in the case of a straight line) of the equation that defines the approximation line. In Figure 7, the first and second adjustments of the transport amount have been made, and the approximation lines for the first and second adjustment points are shown. In this case, the approximation line calculated by the approximation line calculation unit 203 is simply a straight line passing through the two adjustment points. Since the adjustment value can be identified according to the roll diameter from the approximation line calculated in this way, the next transport amount can be corrected, and a stable transport amount can be ensured without being affected by the amount of remaining roll media 41.

[0054] Figure 8 shows the case where the next recording medium P is transported using the adjustment values ​​obtained from the approximation line AL1 (the approximation line shown in Figure 7) based on the first and second adjustment points, and the third adjustment point is obtained. In this case, the approximation line calculation unit 203 calculates the approximation line AL2, which is a straight line, using the least squares method for the first to third adjustment points. The approximation line calculation unit 203 then shifts the calculated approximation line AL2 (i.e., shifts the intercept while keeping the slope the same) to update the approximation line AL3, which is a straight line passing through the latest third adjustment point, as the approximation line as the result of the third transport amount adjustment. The adjustment value obtained in the third adjustment is considered correct, and the slope of the approximation line based on the adjustment values ​​accumulated up to that point (approximation line AL2 in the example in Figure 8) is adopted for the rate of change (slope) between the roll diameter and the adjustment value. The approximation line calculation unit 203 calculates and updates the approximation line in the same way for the fourth and subsequent transport amount adjustments.

[0055] The approximation line calculation unit 203 calculates an approximation line using previously calculated adjustment points or the least squares method, and then shifts this approximation line to obtain a straight line passing through the latest adjustment point as the final approximation line. However, it is not necessarily limited to this, and the approximation line obtained by the least squares method without such shifting may also be used as the final approximation line.

[0056] The ejection control unit 204 is a functional unit that controls the movement of the carriage 5 in the main scanning direction and the ejection operation of ink from the recording head 6 by outputting dot data based on the ejection amount of each ink converted from image data received by the host I / F 109 to the print control unit 106 and the motor drive unit 107.

[0057] The transport control unit 205 is a functional unit that controls the transport operation of the recording medium P in the sub-scanning direction by controlling the motor drive unit 107 based on the dot data described above. In this case, the transport control unit 205 transports the recording medium P after correcting the transport amount. Specifically, the transport control unit 205 identifies an adjustment value corresponding to the roll diameter of the roll media 41 at that time from the latest approximation line calculated by the approximation line calculation unit 203, and calculates the corrected transport amount by adding this adjustment value to the target transport amount (ideal transport amount). Then, the transport control unit 205 outputs a command value to the motor drive unit 107 to transport only the corrected transport amount. The timing of the calculation of the corrected adjustment value by the transport control unit 205 may be when the approximation line is calculated by the approximation line calculation unit 203, or immediately before the next transport of the recording medium P, etc. Furthermore, the roll diameter of the roll media 41 may be obtained by directly measuring it with a sensor, for example, or it may be calculated based on the total value of the actual transport amount transported by the transport roller 17.

[0058] The memory unit 206 is a functional unit that stores, for example, data relating the adjustment value calculated by the adjustment value calculation unit 202 to the roll diameter of the roll media 41 at the time of transport of the recording medium P, and data of the approximation line calculated (or updated) by the approximation line calculation unit 203. The memory unit 206 is implemented by the RAM 103 or NVRAM 104 shown in Figure 5.

[0059] The transport amount acquisition unit 201, adjustment value calculation unit 202, approximation line calculation unit 203, discharge control unit 204, and transport control unit 205 described above are implemented, for example, by a program executed by the CPU 101 shown in Figure 5. Note that some or all of these functional units may be implemented not by a software program, but by hardware circuits (integrated circuits) such as FPGAs (Field-Programmable Gate Arrays) or ASICs.

[0060] Furthermore, the functional units of the control unit 100 of the image forming apparatus 1 shown in Figure 6 are conceptual representations of their functions and are not limited to this configuration. For example, the multiple functional units shown as independent functional units in the control unit 100 of the image forming apparatus 1 shown in Figure 6 may be configured as a single functional unit. On the other hand, the functions of a single functional unit in the control unit 100 of the image forming apparatus 1 shown in Figure 6 may be divided into multiple functions and configured as multiple functional units.

[0061] (An operation to correct the amount of recording medium transported in an image forming apparatus) Figure 9 is a flowchart showing an example of the operation flow for correcting the transport amount of the recording medium in the image forming apparatus according to this embodiment. Referring to Figure 9, the operation flow for correcting the transport amount of the recording medium P in the image forming apparatus 1 according to this embodiment will be explained.

[0062] <Step S11> The transport control unit 205 of the control unit 100 intermittently transports the recording medium P in the sub-scanning direction by controlling the rotation of the transport motor 51 via the motor drive unit 107. Then, the process proceeds to step S12.

[0063] <Step S12> The transport amount acquisition unit 201 of the control unit 100 acquires the transport amount (actual transport amount) of the recording medium P transported in the sub-scanning direction by the transport motor 51 controlled by the transport control unit 205, via the encoder 56 and I / O 108. Then, the process proceeds to step S13.

[0064] <Step S13> The adjustment value calculation unit 202 of the control unit 100 calculates the difference between the target transport amount (ideal transport amount) and the actual transport amount obtained by the transport amount acquisition unit 201, and calculates an adjustment value for the target transport amount based on this difference. The adjustment value calculation unit 202 then stores the calculated adjustment value in the storage unit 206, associating it with the roll diameter of the roll media 41 at the time of transport of the recording medium P and the type of recording medium P (e.g., brand name). Then, the process proceeds to step S14.

[0065] <Step S14> The approximation line calculation unit 203 of the control unit 100 calculates an approximation line for each adjustment point on the two-dimensional coordinate plane determined by the adjustment value calculated by the adjustment value calculation unit 202 and the roll diameter corresponding to that adjustment value, for the type of recording medium P being used. Then, the process proceeds to step S15.

[0066] <Step S15> The transport control unit 205 of the control unit 100 identifies an adjustment value corresponding to the roll diameter of the roll media 41 at that time from the latest approximation line calculated by the approximation line calculation unit 203, and calculates the corrected transport amount by adding this adjustment value to the target transport amount (ideal transport amount). Then, the transport control unit 205 outputs a command value to the motor drive unit 107 to transport only the corrected transport amount.

[0067] In the sequence of steps S11 to S15 described above, the image forming apparatus 1 performs an operation to correct the amount of recording medium P that is transported.

[0068] As described above, in the image forming apparatus 1 according to this embodiment, the paper feed drive unit 32 feeds the recording medium P from the roll media 41, the transport roller 17 transports the recording medium P, the transport amount acquisition unit 201 acquires the actual transport amount, which is the actual amount of recording medium P transported by the transport roller 17, the adjustment value calculation unit 202 calculates an adjustment value for the ideal transport amount based on the difference between the ideal transport amount and the actual transport amount acquired by the transport amount acquisition unit 201, the approximation line calculation unit 203 calculates an approximation line for the adjustment point determined by the adjustment value calculated by the adjustment value calculation unit 202 and the roll diameter of the roll media 41 when the recording medium P is transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media 41, and the transport control unit 205 identifies the adjustment value corresponding to the roll diameter of the roll media 41 from the approximation line and corrects the transport amount by the transport roller 17 using the adjustment value. As a result, even if the roll diameter of the roll media changes, the desired transport amount can be secured.

[0069] (Variation 1) Figure 10 shows an example of an approximation curve for adjustment values ​​used in the image forming apparatus according to the modified embodiment 1. Referring to Figure 10, the approximation curve calculated by the image forming apparatus 1 according to this modified embodiment will be explained, focusing on the differences from the embodiment described above.

[0070] In the above embodiment, the approximation line calculated by the approximation line calculation unit 203 was an approximate straight line defined by a linear function. However, when the torque accompanying the rotation of the roll media 41 is constant, the tension on the recording medium P supplied from the roll media 41 is inversely proportional to the roll diameter, and the inertia of the roll media 41 is proportional to the square of the roll diameter. Therefore, the adjustment value for bringing the actual conveying amount closer to the ideal conveying amount is not necessarily a straight line defined by a linear function of the roll diameter due to these combined factors. Thus, in this modified example, the approximation line is a curve defined by an n-degree polynomial of order 2 or higher, or a logarithmic function, based on multiple adjustment points calculated by adjusting the conveying amount.

[0071] As shown in Figure 10, if the approximation line calculation unit 203 has obtained multiple adjustment points, it calculates an approximation line AL11, which is a curve, using the least squares method or the like for these adjustment points.

[0072] The transport control unit 205 identifies an adjustment value corresponding to the roll diameter of the roll media 41 at that time from the latest approximation line (curve) calculated by the approximation line calculation unit 203, and calculates the corrected transport amount by adding this adjustment value to the target transport amount (ideal transport amount). Then, the transport control unit 205 outputs a command value to the motor drive unit 107 to transport only the corrected transport amount.

[0073] The operation of the other functional units of the control unit 100 is as described above in the above embodiment.

[0074] As described above, by approximating the approximation line calculated from the adjustment value with a curve instead of limiting it to a straight line, it is possible to achieve highly accurate correction of the conveying amount according to the roll diameter.

[0075] (Modification 2) Figure 11 shows an example of an approximation line calculated by excluding outliers, used in the image forming apparatus according to the modified embodiment 2. Referring to Figure 11, the approximation line calculated by the image forming apparatus 1 according to this modified embodiment will be explained, focusing on the differences from the embodiment described above.

[0076] As described in the above embodiment, the adjustment value is calculated by the adjustment value calculation unit 202. However, due to abnormalities in the transport operation of the motor drive unit 107 to the roll media 41, or poor transport of the recording medium P by the roll media 41, the adjustment value calculated by the adjustment value calculation unit 202 may show an abnormal value compared to the adjustment values ​​obtained so far. If this abnormal adjustment value is used for calculating the approximation line by the approximation line calculation unit 203, it may adversely affect the accuracy of the transport amount correction. Therefore, in this modified example, if there is an abnormal value among the multiple adjustment points calculated by adjusting the transport amount, the abnormal value is excluded when calculating the approximation line.

[0077] The approximation line calculation unit 203 determines, for example, as shown in Figure 11, that the adjustment value of an adjustment point that is clearly separated from the positions of other adjustment points is an abnormal value, and calculates an approximation line AL21 for the other adjustment points excluding the adjustment point with the abnormal value.

[0078] One method for determining whether an adjustment value is an outlier is to consider it an outlier if, for example, σ is a value indicating the variability of the adjustment value (e.g., standard deviation or variance), and the condition outlier > Xσ (X: predetermined coefficient) is met.

[0079] Furthermore, in cases where the recording medium P is transported in a skewed state, or when the recording medium P has been transported once, rewound, and then transported again, the actual transport amount obtained by the transport amount acquisition unit 201 is likely to be incorrect. Therefore, it is desirable for the approximation line calculation unit 203 to exclude the adjustment value based on the actual transport amount as an abnormal value. In this case, a method for detecting the skewed state is to determine if the skew amount, which is determined based on the position of the end of the recording medium P detected by the end detection sensor 20, satisfies the condition skew amount > Y [mm / m] (Y: predetermined value). Also, a method for determining whether the recording medium P has been transported once, rewound, and is being transported again is to refer to the operation history of the image forming apparatus 1.

[0080] As described above, by excluding outliers from the calculated adjustment values ​​and then calculating the approximation line, it is possible to achieve highly accurate correction of the transport volume.

[0081] (Variation 3) Figure 12 shows an example of an approximation line calculated taking abnormal values ​​into account, used in the image forming apparatus according to the modified embodiment 3. Referring to Figure 12, the approximation line calculated in the image forming apparatus 1 according to this modified embodiment will be explained, focusing on the differences from the embodiment described above.

[0082] In the above-mentioned Modification 2, the adjustment value determined to be an outlier was excluded, and the approximation line was calculated based on the remaining adjustment values. In this Modification, if the latest adjustment value is an outlier, that adjustment value is excluded when calculating the slope of the approximation line, but the approximation line obtained from the excluded adjustment value is shifted in parallel so that it passes through the adjustment point of the outlier, and this straight line is calculated as the final approximation line.

[0083] Figure 12 shows the case where the latest (current) adjustment value calculated by the adjustment value calculation unit 202 is determined to be an abnormal value. In this case, the approximation line calculation unit 203 first calculates an approximation line AL31, which is an approximation line for the other adjustment points excluding the adjustment point of the abnormal value. Then, the approximation line calculation unit 203 shifts the calculated approximation line AL31 in parallel (i.e., shifts the intercept while keeping the slope the same) to calculate an approximation line AL32, which is a straight line passing through the latest adjustment point (abnormal value), as the approximation line as the result of the latest adjustment of the transport amount.

[0084] This makes it possible to correct the transport volume to match the transport operation at the time of the latest adjustment, thereby achieving highly accurate transport volume correction.

[0085] (Modification 4) Figure 13 shows an example of an approximation line calculated using the most recent adjustment value in the image forming apparatus according to the modified embodiment 4. Referring to Figure 13, the approximation line calculated in the image forming apparatus 1 according to this modified embodiment will be explained, focusing on the differences from the embodiment described above.

[0086] In this modified example, we will explain the operation to exclude the previously calculated adjustment values ​​when a discrepancy arises between the recently calculated adjustment values ​​and the previously calculated adjustment values ​​due to changes in the image forming apparatus 1 over time.

[0087] In the example shown in Figure 13, the approximation line AL42 calculated by the approximation line calculation unit 203 based on the adjustment points of the most recent n (for example, n=10) adjustment values, and the approximation line AL41 calculated by the approximation line calculation unit 203 based on the adjustment points of past n adjustment values ​​are shown. Here, the past n adjustment values ​​may be, for example, past n adjustment values ​​that do not include any of the most recent n adjustment values, or n adjustment values ​​that include some of the older adjustment values ​​from the most recent n adjustment values. For example, if 50 values ​​have been obtained as adjustment values ​​and n=10, the most recent n=10 adjustment values ​​are the 41st to 50th adjustment values, while the past n=10 adjustment values ​​may be the 31st to 40th adjustment values ​​that do not overlap with the most recent ones, or the 36th to 45th adjustment values ​​that do overlap with the most recent ones.

[0088] The approximation line calculation unit 203 calculates, for example, the difference between the slope of the approximation line based on the adjustment points of the most recent n adjustment values ​​(an example of the second group of adjustment values) and the slope of the approximation line based on the adjustment points of past n adjustment values ​​(an example of the first group of adjustment values). If the absolute value of this difference > Z (Z: predetermined value), the unit selects the approximation line based on the adjustment points of the most recent n adjustment values ​​as the final approximation line to be used for correcting the transport amount.

[0089] This makes it possible to achieve highly accurate correction of the conveying amount even when the adjustment value is deviated due to changes over time caused by wear of the conveying roller 17 or pre-guide plate 16a, by selecting a new set of adjustment values ​​and calculating an approximate line.

[0090] (Variation 5) Figure 14 shows an example of the configuration of the functional block of the control unit of the image forming apparatus according to the modified embodiment 5. Figure 15 shows an example of an approximation line calculated in response to temperature, used in the image forming apparatus according to the modified embodiment 5. Referring to Figures 14 and 15, the image forming apparatus 1 according to this modified embodiment will be described, focusing on the differences from the above-described embodiment.

[0091] The amount of recording medium P transported may change depending on environmental conditions such as temperature or humidity, and in such cases, the calculated adjustment value and approximation line may also change depending on those environmental conditions. This modified example describes the operation of calculating the approximation line and correcting the amount of transported according to environmental conditions. In the following description, we focus on temperature as the environmental condition, but this is not limited to this; humidity may also be used, or both temperature and humidity may be used, etc.

[0092] As shown in Figure 14, the image forming apparatus 1 according to this modified example is equipped with a control unit 100a instead of the control unit 100 of the above-described embodiment. Furthermore, the image forming apparatus 1 is equipped with a temperature sensor (not shown) for detecting the ambient temperature. The hardware configuration of the control unit 100a is the same as that of the control unit 100 in the above-described embodiment.

[0093] As shown in Figure 14, the control unit 100a of the image forming apparatus 1 includes a transport amount acquisition unit 201, an adjustment value calculation unit 202, an approximation line calculation unit 203, a discharge control unit 204, a transport control unit 205, a storage unit 206, and a temperature acquisition unit 207.

[0094] The temperature acquisition unit 207 is a functional unit that acquires the temperature detected by the temperature sensor described above via the I / O 108.

[0095] The adjustment value calculation unit 202 calculates the difference between the target transport amount (ideal transport amount) and the actual transport amount obtained by the transport amount acquisition unit 201, and calculates an adjustment value for the target transport amount based on this difference. The adjustment value calculation unit 202 then stores the temperature obtained by the temperature acquisition unit 207, the calculated adjustment value, the roll diameter of the roll media 41 at the time of transport of the recording medium P, and the type of recording medium P (e.g., brand name) in the storage unit 206, associating them. Here, the temperature associated with the adjustment value, roll diameter, and type may be a temperature range with a predetermined width, such as 5~15[°C], 15~25[°C], or 25~35[°C]. For example, Figure 15 shows an example in which adjustment points are distinguished for each of the four temperature ranges (temperature (1)~(4)), and an approximation line is calculated for each distinguished group of adjustment points.

[0096] The approximation line calculation unit 203 calculates an approximation line based on the adjustment point group corresponding to each temperature.

[0097] The operation of the other functional units is the same as in the embodiment described above.

[0098] This allows the temperature acquisition unit 207 to identify an adjustment value from an approximation line corresponding to the temperature, and to correct the transport volume using this adjustment value. As a result, it is possible to perform highly accurate correction of the transport volume while suppressing the effects of changes in the temperature environment.

[0099] (Experimental variation 6) Figure 16 shows an example of a straight line in a correction formula composed of representative values ​​used in the image forming apparatus according to the modified embodiment 6. Referring to Figure 16, the approximation line calculated by the image forming apparatus 1 according to this modified embodiment will be explained, focusing on the differences from the embodiment described above.

[0100] If the transport volume has not yet been adjusted, or if the transport volume has only been adjusted once, the approximation line calculation unit 203 cannot calculate an approximation line. In this modified example, if there is no approximation line calculated by the approximation line calculation unit 203, the operation of identifying an adjustment value from a straight line of a correction formula composed of representative values ​​corresponding to the type of recording medium P being used, and correcting the transport volume using that adjustment value will be explained.

[0101] If, as described above, there is no approximation line calculated by the approximation line calculation unit 203, the transport control unit 205 refers to the storage unit 206 and identifies an adjustment value corresponding to the roll diameter of the roll media 41 at that time from a straight line of a correction formula (representative straight line RL shown in Figure 16) composed of representative values ​​corresponding to the type of recording medium P being used, and adds this adjustment value to the target transport amount (ideal transport amount) to calculate the corrected transport amount.

[0102] Furthermore, if the adjustment value calculation unit 202 has calculated the adjustment value once, as shown in Figure 16, the approximation line calculation unit 203 may shift the representative line RL in parallel (i.e., shift the intercept while keeping the slope the same) to calculate the approximation line AL61, which is a line passing through the first adjustment point, as the approximation line resulting from the first adjustment of the transport amount. Also, the approximation line AL62 shown in Figure 16 is an approximation line calculated by the approximation line calculation unit 203 after the second adjustment of the transport amount has been completed.

[0103] The storage unit 206 further stores correction formula data, which consists of representative values ​​corresponding to each type of recording medium P.

[0104] Furthermore, the correction formulas stored in the memory unit 206 are not limited to those corresponding to each type of recording medium P, and may also store correction formula data corresponding to each width and thickness of the recording medium P. In this case, the correction formula data corresponding to the type, width, and thickness of the recording medium P being used should be used.

[0105] As described above, when an approximation line cannot be calculated due to an insufficient number of adjustment values, it is possible to suppress the phenomenon in which the actual transport volume deviates significantly from the ideal transport volume by identifying adjustment values ​​from a straight line of a correction formula composed of representative values, that is, a straight line defined by a predetermined correction formula, and using it to correct the transport volume.

[0106] The embodiments of the present invention are as follows. <1> A paper feed unit that feeds recording media from roll media, A transport roller for transporting the recording medium, An acquisition unit that acquires the actual transport amount, which is the actual amount of the recording medium transported by the transport roller, A first calculation unit calculates an adjustment value for the ideal transport amount based on the difference between the ideal transport amount and the actual transport amount obtained by the acquisition unit, A second calculation unit calculates an approximate line for an adjustment point determined by the adjustment value calculated by the first calculation unit and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media, A correction unit that identifies an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line and corrects the amount conveyed by the conveying roller using the adjustment value, This is a conveying device equipped with [a specific feature / feature]. <2> The first calculation unit stores the type of roll media, the calculated adjustment value, and the roll diameter of the roll media in a storage unit, associating them with each other. The second calculation unit refers to the storage unit and calculates the approximation line for the adjustment point determined by the adjustment value corresponding to the type of roll media in use and the roll diameter. <1> This is the conveying device described in [reference]. <3> The second calculation unit calculates the approximation line using the adjustment values ​​calculated by the first calculation unit, excluding the adjustment values ​​that were determined to be abnormal. <1> or <2> This is the conveying device described in [reference]. <4> The second calculation unit determines that the adjustment value calculated by the first calculation unit is an abnormal value when the recording medium is transported in a skewed state. <3> This is the conveying device described in [reference]. <5> The second calculation unit determines that the adjustment value calculated by the first calculation unit is an abnormal value when the recording medium is rewound and retransmitted. <3> This is the conveying device described in [reference]. <6> If the second calculation unit determines that the latest adjustment value calculated by the first calculation unit is an abnormal value, it calculates an approximate straight line for the other adjustment values ​​calculated by the first calculation unit excluding the abnormal value, and calculates the approximate line as the line obtained by translating the approximate straight line so that it passes through the adjustment point of the abnormal value. <1> or <2> This is the conveying device described in [reference]. <7> If the second calculation unit determines that there is a difference between the approximation line based on the first group of adjustment values ​​calculated by the first calculation unit and the approximation line based on the second group of adjustment values ​​which is newer than the first group of adjustment values, it selects the approximation line based on the second group of adjustment values ​​as the approximation line to be used for correction by the correction unit. <1> ~ <6> It is a conveying device as described in any one of the items. <8> The first calculation unit stores the environmental conditions of the conveying device, the calculated adjustment value, and the roll diameter of the roll media in a storage unit, relating them together. The second calculation unit refers to the storage unit and calculates the approximate line for the adjustment point determined by the adjustment value corresponding to the current environmental conditions of the conveying device and the roll diameter. <1> ~ <7> It is a conveying device as described in any one of the items. <9> If there is no approximation line for correcting the amount conveyed by the conveyor roller, the correction unit identifies an adjustment value corresponding to the roll diameter of the roll media from a straight line of a correction formula composed of representative values ​​corresponding to the type of roll media being used, and corrects the amount conveyed by the conveyor roller using this adjustment value. <1> ~ <8> It is a conveying device as described in any one of the items. <10> <1> ~ <9> A conveying device as described in any one of the items, A printing unit that prints on the recording medium, This is an image forming apparatus equipped with the following features. <11> An acquisition step to obtain the actual transport amount, which is the actual amount of recording medium transported by a transport roller that transports the recording medium fed from roll media, A first calculation step involves calculating an adjustment value for the ideal transport volume based on the difference between the ideal transport volume and the actual transport volume obtained. A second calculation step involves calculating an approximate line for an adjustment point determined by the calculated adjustment value and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media. A correction step involves identifying an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line, and correcting the amount conveyed by the conveying roller using the adjustment value. This is a transport method that has [a certain feature]. <12> On the computer, An acquisition step to obtain the actual transport amount, which is the actual amount of recording medium transported by a transport roller that transports the recording medium fed from roll media, A first calculation step involves calculating an adjustment value for the ideal transport volume based on the difference between the ideal transport volume and the actual transport volume obtained. A second calculation step involves calculating an approximate line for an adjustment point determined by the calculated adjustment value and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media. A correction step involves identifying an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line, and correcting the amount conveyed by the conveying roller using the adjustment value. This is a program to execute [the command / action].

[0107] In the embodiments and variations described above, if at least one of the functions of the image forming apparatus 1 is realized by program execution, the program is provided pre-installed in ROM or the like. Furthermore, in the embodiments and variations described above, the program executed by the image forming apparatus 1 may be provided as an installable or executable file recorded on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), flexible disk (FD), CD-R (Compact Disk-Recordable), or DVD (Digital Versatile Disc). Also, in the embodiments and variations described above, the program executed by the image forming apparatus 1 may be provided by storing it on a computer connected to a network such as the Internet and allowing it to be downloaded via the network. Furthermore, in the embodiments and variations described above, the program executed by the image forming apparatus 1 may be provided or distributed via a network such as the Internet. Additionally, in the embodiments and variations described above, the program executed by the image forming apparatus 1 has a modular configuration including at least one of the above-described functional units, and in actual hardware, the CPU reads the program from the above-described storage device and executes it, thereby loading and generating the above-described functional units onto the main memory. [Explanation of Symbols]

[0108] 1. Image forming apparatus 2 Covers 3 Guide Rods 4. Sub-guide rail 5 carriages 6, 6c, 6k, 6m, 6y recording head 7. Cartridge loading section 8 Main scanning motor 9 Drive pulley 10 Pressure pulley 11 Timing belt 13 Encoders 14 Encoder Sheet 15 Maintenance mechanism 16 Platen 16a Pre-guide board 16b Post guide plate 17 Conveyor rollers 18 Pinch Roller 20 End detection sensors 30 Main unit of the device 31 Support stand 32 Paper feed drive unit 33 Winding drive unit 41 Roll Media 42 Rolling paper tube 51 Conveyor motor 52 Drive pulley 53 belt 54 Driven pulley 55 Encoder Sheet 56 encoders 100, 100a Control Unit 101 CPU 102 ROM 103 RAM 104 NVRAM 105 ASIC 106 Printing Control Unit 107 Motor drive unit 108 I / O 109 Host I / F 120 Control Panel 140 Head Driver 170 hosts 201 Transport volume acquisition unit 202 Adjustment Value Calculation Unit 203 Approximate line calculation section 204 Discharge Control Unit 205 Transport Control Unit 206 Memory section 207 Temperature acquisition section AL1~AL3, AL11, AL21 approximate line AL31, AL32, AL41, AL42 approximate line AL51~AL54, AL61, AL62 approximate line P recording medium RL represents a straight line [Preliminary Technology Documents] [License]

[0109] [License 1] Patent No. 5734508

Claims

1. A paper feed unit that feeds recording media from roll media, A transport roller for transporting the recording medium, An acquisition unit that acquires the actual transport amount, which is the actual amount of the recording medium transported by the transport roller, A first calculation unit calculates an adjustment value for the ideal transport amount based on the difference between the ideal transport amount and the actual transport amount obtained by the acquisition unit, A second calculation unit calculates an approximate line for an adjustment point determined by the adjustment value calculated by the first calculation unit and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media, A correction unit that identifies an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line and corrects the amount conveyed by the conveying roller using the adjustment value, Equipped with, The first calculation unit stores the type of roll media, the calculated adjustment value, and the roll diameter of the roll media in a storage unit, associating them with each other. The second calculation unit is a conveying device that, by referring to the storage unit, calculates the approximate line for the adjustment point determined by the adjustment value corresponding to the type of roll media in use and the roll diameter.

2. The transport device according to claim 1, wherein the second calculation unit calculates the approximation line using the adjustment values ​​that have been determined to be abnormal values ​​from the adjustment values ​​calculated by the first calculation unit.

3. The transport device according to claim 2, wherein the second calculation unit determines the adjustment value calculated by the first calculation unit to be an abnormal value when the recording medium is transported in a skewed state.

4. The transport device according to claim 2, wherein the second calculation unit determines that the adjustment value calculated by the first calculation unit is an abnormal value when the recording medium is rewound and transported again.

5. The conveying device according to claim 1, wherein if the second calculation unit determines that the latest adjustment value calculated by the first calculation unit is an abnormal value, it calculates an approximate straight line for the other adjustment values ​​calculated by the first calculation unit excluding the abnormal value, and calculates a straight line obtained by translating the approximate straight line so that it passes through the adjustment point of the abnormal value as the approximate line.

6. The transport device according to claim 1, wherein the second calculation unit determines that there is a difference between the approximation line based on the first group of adjustment values ​​and the approximation line based on the second group of adjustment values ​​which is newer than the first group of adjustment values, among the adjustment values ​​calculated by the first calculation unit, and selects the approximation line based on the second group of adjustment values ​​as the approximation line to be used for correction by the correction unit.

7. The first calculation unit stores the environmental conditions of the conveying device, the calculated adjustment value, and the roll diameter of the roll media in the storage unit, relating them together. The conveying device according to claim 1, wherein the second calculation unit refers to the storage unit and calculates the approximate line for the adjustment point determined by the adjustment value corresponding to the current environmental conditions of the conveying device and the roll diameter.

8. The conveying device according to claim 1, wherein, if there is no approximation line for correcting the amount conveyed by the conveying roller, the correction unit identifies an adjustment value corresponding to the roll diameter of the roll media from a straight line of a correction formula composed of representative values ​​corresponding to the type of roll media being used, and corrects the amount conveyed by the conveying roller using the adjustment value.

9. The conveying device according to claim 1, A printing unit that prints on the recording medium, An image forming apparatus equipped with [a specific feature].

10. An acquisition step to obtain the actual transport amount, which is the actual amount of recording medium transported by a transport roller that transports the recording medium fed from roll media, A first calculation step involves calculating an adjustment value for the ideal transport volume based on the difference between the ideal transport volume and the actual transport volume obtained. A second calculation step involves calculating an approximate line for an adjustment point determined by the calculated adjustment value and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media. A correction step involves identifying an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line, and correcting the amount conveyed by the conveying roller using the adjustment value. It has, The first calculation step involves associating the type of roll media, the calculated adjustment value, and the roll diameter of the roll media and storing them in the storage unit. The second calculation step is a conveying method that refers to the storage unit and calculates the approximate line for the adjustment point determined by the adjustment value corresponding to the type of roll media in use and the roll diameter.

11. On the computer, An acquisition step to obtain the actual transport amount, which is the actual amount of recording medium transported by a transport roller that transports the recording medium fed from roll media, A first calculation step involves calculating an adjustment value for the ideal transport volume based on the difference between the ideal transport volume and the actual transport volume obtained. A second calculation step involves calculating an approximate line for an adjustment point determined by the calculated adjustment value and the roll diameter of the roll media when the recording medium has been transported by the actual transport amount, in a two-dimensional coordinate plane determined by the adjustment value and the roll diameter of the roll media. A correction step involves identifying an adjustment value corresponding to the roll diameter of the roll media from the aforementioned approximation line, and correcting the amount conveyed by the conveying roller using the adjustment value. Make it run, The first calculation step involves associating the type of roll media, the calculated adjustment value, and the roll diameter of the roll media and storing them in the storage unit. The second calculation step is a program for calculating the approximate line for the adjustment point determined by the adjustment value corresponding to the type of roll media in use and the roll diameter, by referring to the storage unit.

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