Control System

Abstract

To provide a technique which can move a movable body at a high speed while suppressing an influence of deterioration in control accuracy caused by an inhibitor adhering to an encoder scale.SOLUTION: The movement of movable bodies 11, 12 configured so as to process an object is controlled by a controller 32. A measuring instrument 34 measures a state quantity showing the movement state of the movable bodies based on an encoder signal. The controller controls the movement of the movable bodies by controlling a motor 13 based on the measured state quantity. The controller determines presence or absence of an inhibition area as a movement area of the movable bodies read by a sensor in a portion in an encoder scale to which an inhibitor inhibiting accurate reading of an encoder scale 46 by the sensor 47. The controller selects ones (S380, S390) from a plurality of control methods including a first control method and a second control method according to the presence or absence of the determined inhibition area, and controls the movement of the movable bodies by the selected control methods.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to control systems. [Background technology]

[0002] In inkjet printers, a technique is known for increasing the movement speed of a carriage carrying an inkjet head in non-image areas between image areas, thereby speeding up processing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-22115 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a system that processes an object by moving a carriage carrying a processing head, the position and speed of the carriage are measured by, for example, reading an encoder scale with a sensor that moves together with the carriage. The measured position and speed are used to control the movement of the carriage.

[0005] If an obstruction that impedes reading is present on the encoder scale, measurement using this encoder scale cannot be performed normally, at least when the carriage and the sensor pass through an area corresponding to the location of the obstruction. For example, when the processing head is an inkjet head, if the encoder scale is stained with ink, the stain will impede normal reading of the encoder scale.

[0006] When the carriage accelerates or decelerates at high speeds, even a slight interruption in time can make it difficult to accurately grasp the carriage's movement state, which can make it difficult to properly control the carriage's movement.

[0007] Therefore, according to one aspect of the present disclosure, in a system for controlling the movement of a moving body that processes an object, it is desirable to provide a technology that enables the moving body to move at high speed while suppressing the effects of reduced control accuracy caused by obstructions adhering to the encoder scale. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, there is provided a control system including a motor, a moving body, an encoder, a measuring instrument, and a controller, the moving body being configured to be driven by the motor to move on a passageway and process an object.

[0009] The encoder includes an encoder scale and a sensor configured to move relative to the encoder scale in conjunction with the movable body and to output an encoder signal based on reading the encoder scale.

[0010] The measuring device measures a state quantity representing a moving state of the movable body on the passage based on the encoder signal, and the controller is configured to control the motor based on the measured state quantity, thereby controlling the movement of the movable body.

[0011] The movement path of the moving body from the start point of movement to the stop point includes an acceleration section where the moving body transitions from the start point of movement to a constant speed state, a deceleration section where the moving body moves from the constant speed state to a stop point, and an intermediate section between the acceleration section and the deceleration section, and the intermediate section includes a processing section where the moving body processes the target object.

[0012] The controller determines whether or not a portion of the encoder scale to which an obstruction that obstructs normal reading of the encoder scale by the sensor is attached is within an intermediate section of an obstruction area, which is a movement area of ​​the movable body read by the sensor.

[0013] The controller selects one of a plurality of control methods, including a first control method and a second control method, depending on the presence or absence of the determined inhibition area, and controls the movement of the moving body on the movement path using the selected control method.

[0014] The first control method is a method for controlling the movement of the moving body so that in a processing section of the intermediate section, the moving body is moved at a constant speed of a first speed, and in a non-processing section, which is a section of the intermediate section other than the processing section, the moving body is moved at least partially at a constant speed of a second speed that is higher than the first speed. The first control method is selected when it is determined that there is no inhibition region.

[0015] The second control method is a method for controlling the movement of the moving body so as to move the moving body at a constant speed at a first speed in the processing section and the non-processing section. The second control method is selected when it is determined that there is an inhibition area.

[0016] According to this control system, when an obstruction area is present within the intermediate section, the movement control of the moving object is performed so as to stop the control of moving the moving object at high speed within the intermediate section. With regard to the movement control, the influence of the obstruction of measurement is larger during high speed movement than during low speed movement.

[0017] Therefore, with this control system, the influence of reduced control accuracy in controlling carriage movement caused by the presence of an obstruction area interfering with normal measurement by the measuring instrument can be suppressed, while the carriage can be moved at a higher speed than in a system that does not uniformly move the moving body at a high speed.

[0018] A control system according to another aspect of the present disclosure includes a motor, a moving body, an encoder, a measuring instrument, and a controller. The moving body is configured to be driven by the motor to move on a passage and process an object. The configurations of the encoder and the measuring instrument are similar to those of the above-mentioned control system.

[0019] The movement path of the moving body from the movement start point to the stop point includes an acceleration section in which the moving body moves from the movement start point to a constant speed state, a deceleration section in which the moving body moves from the constant speed state to a stop point, and an intermediate section between the acceleration section and the deceleration section. The intermediate section includes a processing section in which the moving body processes an object.

[0020] The controller determines whether or not an area within the encoder scale to which an obstruction that prevents the sensor from reading the encoder scale properly is present in a non-processing section, which is a section other than the processing section within the intermediate section of the obstruction section, which is the area of ​​movement of the moving body that is read by the sensor.

[0021] The controller selects one of a plurality of control methods, including a first control method and a second control method, depending on the presence or absence of the determined inhibition area, and controls the movement of the moving body on the movement path using the selected control method.

[0022] The first control method is a method for controlling the movement of the moving body so that the moving body is moved at a constant first speed in a processing section of the intermediate section, and is moved at least partially at a constant second speed, which is higher than the first speed, in a non-processing section of the intermediate section. The first control method is selected when it is determined that there is no inhibition region.

[0023] The second control method is a method for controlling the movement of the moving body so that the moving body is moved at a constant speed at a first speed in the processing section and the processing adjacent section, which is a section of the intermediate section adjacent to the processing section and includes an inhibition area, and the moving body is moved at a constant speed at least partially at a second speed in the non-processing section excluding the processing adjacent section. The processing adjacent section may correspond to a section between an end point of the processing section and an end point of the inhibition area. The second control method is selected when it is determined that there is an inhibition area.

[0024] According to this control system, when an inhibition region is present in the intermediate section, control for moving the moving object at high speed is not performed in the section including the inhibition region. Therefore, according to this control system, it is possible to move the moving object at high speed while suppressing the effect on the movement control of the moving object caused by the inhibition region preventing normal measurement by the measuring instrument. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a block diagram illustrating a configuration of an image forming system. [Diagram 2] FIG. 2 is a diagram illustrating the configuration of a printing mechanism and a linear encoder. [Diagram 3] FIG. 11 is an explanatory diagram of dirt adhering to a linear scale. [Figure 4] 4 is a flowchart showing a main process executed by a processor. [Diagram 5] 4 is a flowchart showing a printing process executed by a processor. [Figure 6] 11 is a flowchart (part 1) illustrating a speed profile setting process executed by a processor. [Figure 7] 13 is a flowchart (part 2) illustrating the speed profile setting process executed by the processor. [Figure 8] 11 is a flowchart showing a standard speed profile generation process executed by a processor. [Figure 9] FIG. 9A is a graph illustrating a first standard velocity profile, and FIG. 9B is a graph illustrating a second standard velocity profile. [Figure 10] FIG. 10A is a graph illustrating a third standard velocity profile, and FIG. 10B is a graph illustrating a fourth standard velocity profile. [Figure 11] 11 is a graph illustrating a modified velocity profile relative to a first standard velocity profile. [Figure 12] 12A and 12B are graphs illustrating a modified velocity profile relative to a second standard velocity profile. [Figure 13] 4 is a flowchart showing a motor control process executed by a CR motor control unit for each control period. [Figure 14] 11 is a flowchart showing a correction process repeatedly executed by a linear encoder processing unit. [Figure 15] 13 is a flowchart showing a part of a speed profile setting process according to a modified example. [Figure 16] 16A and 16B are diagrams illustrating a speed profile corrected by extending a constant speed section. [Figure 17] 17A and 17B are diagrams illustrating a speed profile corrected by extending a constant speed section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. The image forming system 1 of this embodiment shown in Fig. 1 is configured as an inkjet printer. The image forming system 1 includes a recording head 11, a carriage 12, a carriage (CR) motor 13, and a linear encoder 14. The recording head 11, the carriage 12, the CR motor 13, and the linear encoder 14 form a part of a printing mechanism 15, the details of which are shown in Fig. 2.

[0027] The print mechanism 15 is configured to receive power from a CR motor 13 to move a carriage 12 carrying the recording head 11 in a main scanning direction. The main scanning direction is a direction perpendicular to the sub-scanning direction in which the paper P is transported.

[0028] The recording head 11 is an ejection head configured to eject ink droplets, and is a so-called inkjet head. When the carriage 12 moves across the paper P in the main scanning direction, the recording head 11 executes an ink droplet ejection operation to form an image on the paper P. The CR motor 13 is a DC motor, and functions as a drive source for reciprocating the carriage 12.

[0029] The linear encoder 14 is an incremental type optical linear encoder, and is used to measure the position and speed in the main scanning direction of the carriage 12. The position and speed of the carriage 12 correspond to state quantities that represent the moving state of the carriage 12, in other words, motion parameters.

[0030] The image forming system 1 further includes a line feed (LF) motor 21 and a rotary encoder 22 (see FIG. 1) to convey the paper P. The LF motor 21 is a DC motor, and functions as a drive source for rotating a conveying roller (not shown) that conveys the paper P in the sub-scanning direction. The rotary encoder 22 is an incremental type optical rotary encoder, and is used to measure the amount of rotation and the rotation speed of the conveying roller.

[0031] The image forming system 1 further includes a head driver 18, a CR motor driver 19, an LF motor driver 29, and an ASIC 2 for driving and controlling the recording head 11, the CR motor 13, and the LF motor 21. The head driver 18 drives the recording head 11 in accordance with a control signal input from the ASIC 2 to cause the recording head 11 to eject ink droplets.

[0032] The CR motor driver 19 drives and rotates the CR motor 13 in accordance with a control signal input from the ASIC 2. The LF motor driver 29 drives and rotates the LF motor 21 in accordance with a control signal input from the ASIC 2.

[0033] The ASIC 2 is configured to control the ink droplet ejection operation by the recording head 11, the transport operation of the carriage 12 by the CR motor 13, and the transport operation of the paper P by the LF motor 21, by inputting control signals to each of the drivers 18, 19, and 29. The ASIC 2 includes a recording control unit 31, a CR motor control unit 32, an LF motor control unit 33, a linear encoder processing unit 34, and a rotary encoder processing unit 35.

[0034] Here, a specific configuration of the printing mechanism 15 included in the image forming system 1 will be described with reference to Fig. 2. The printing mechanism 15 includes a guide shaft 41 in the main scanning direction that defines the path of the carriage 12. The carriage 12 is inserted through this guide shaft 41.

[0035] The carriage 12 is further connected to an endless belt 42 provided along the guide shaft 41. The endless belt 42 is wound between a driving pulley 43 provided at one end of the guide shaft 41 and a driven pulley 44 provided at the other end of the guide shaft 41.

[0036] The drive pulley 43 is rotationally driven by the CR motor 13 to rotate the endless belt 42. The carriage 12 moves in the main scanning direction along the guide shaft 41 by the power of the CR motor 13 transmitted through the rotation of the endless belt 42.

[0037] A linear scale 46 serving as an encoder scale is disposed near the guide shaft 41 along the guide shaft 41. An optical sensor 47 including a light emitting unit 50 and a light receiving unit 60 is mounted on the carriage 12.

[0038] The linear encoder 14 is composed of this optical sensor 47 and linear scale 46. The detailed configuration of the optical sensor 47 is shown in a dashed balloon in the lower right of Fig. 2. As shown in the figure, the linear scale 46 has slits 48 arranged at predetermined intervals in the longitudinal direction corresponding to the main scanning direction. The slits 48 may be holes, or may be made of a transparent material that can transmit light. The light-emitting unit 50 and the light-receiving unit 60 that make up the optical sensor 47 are arranged to sandwich the linear scale 46.

[0039] The light-emitting section 50 includes two light-emitting elements 51, 52, specifically, an A-phase light-emitting element 51 and a B-phase light-emitting element 52. The light-receiving section 60 includes two light-receiving elements 61, 62 corresponding to the two light-emitting elements 51, 52, specifically, an A-phase light-receiving element 61 and a B-phase light-receiving element 62. Light emitted from the A-phase light-emitting element 51 is received by the A-phase light-receiving element 61, and light emitted from the B-phase light-emitting element 52 is received by the B-phase light-receiving element 62.

[0040] The optical sensor 47 is fixed to the carriage 12, and moves in the main scanning direction along the linear scale 46 in conjunction with the carriage 12. Due to this movement, the optical sensor 47 moves relatively to the linear scale 46 in the main scanning direction.

[0041] The light receiving states of the light receiving elements 61, 62 change due to a change in the relative position between the optical sensor 47 and the linear scale 46. The optical sensor 47 outputs two types of pulse signals according to the change in the light receiving state as encoder signals.

[0042] That is, the optical sensor 47 outputs two types of pulse signals having a predetermined phase difference (90 degrees in this embodiment) in response to the movement of the carriage 12. The first pulse signal is an A-phase signal corresponding to the light receiving state of the A-phase light receiving element 61, and the second pulse signal is a B-phase signal corresponding to the light receiving state of the B-phase light receiving element 62.

[0043] The linear encoder processing unit 34 determines the moving direction of the carriage 12 based on the above-mentioned A-phase signal and B-phase signal input as encoder signals from the linear encoder 14, and measures the position and speed of the carriage 12. The linear encoder processing unit 34, together with the linear encoder 14, functions as a measuring instrument for the position and speed of the carriage 12. The measured values ​​of the position and speed of the carriage 12 are input to the recording control unit 31 and the CR motor control unit 32.

[0044] The position and speed of the carriage 12 are measured based on at least one of the A-phase signal and the B-phase signal. For ease of explanation, an example will be described in which the position and speed of the carriage 12 are measured based on the A-phase signal.

[0045] According to this example, the linear encoder processing unit 34 detects the rising edge and the falling edge of the A-phase signal input from the linear encoder 14. Every time such an edge is detected, the count value of a position counter (not shown) is updated. This count value corresponds to the measurement value of the position of the carriage 12.

[0046] The linear encoder processor 34 measures the speed of the carriage 12 based on the time from when the previous edge is detected to when the current edge is detected, i.e., the edge interval, in synchronization with the detection timing of each edge of the A-phase signal. The speed is proportional to the inverse of the edge interval.

[0047] The recording control unit 31 generates a control signal for the recording head 11 based on the measurement values ​​input from the linear encoder processing unit 34, and inputs the generated control signal to the head driver 18. The head driver 18 drives the recording head 11 in accordance with the control signal input from the recording control unit 31, thereby causing the recording head 11 to eject ink droplets according to the position of the carriage 12.

[0048] The CR motor control unit 32 calculates an operation amount U for the CR motor 13 for each predetermined control period based on the measurement value input from the linear encoder processing unit 34. The operation amount U may be an operation amount specifying the power to be applied to the CR motor 13, and in particular, may be a voltage command value specifying the voltage to be applied to the CR motor 13. However, the operation amount U may also be a current command value specifying the current to be applied to the CR motor 13, or may be a PWM value.

[0049] The CR motor control unit 32 inputs a PWM signal for applying power corresponding to the calculated operation amount U to the CR motor 13 to the CR motor driver 19 as a control signal for the CR motor 13 .

[0050] The CR motor driver 19 drives the CR motor 13 in accordance with a control signal input from a CR motor control unit 32. Driven by the CR motor 13, the carriage 12 and the recording head 11 move in the main scanning direction.

[0051] The rotary encoder 22 is configured to output two types of pulse signals having a predetermined phase difference (90 degrees in this embodiment) as encoder signals in response to rotation of the LF motor 21. The encoder signals are input to a rotary encoder processing unit 35 of the ASIC 2.

[0052] The rotary encoder processing unit 35 measures the rotation amount and rotation speed of the transport roller that transports the paper P based on the encoder signal input from the rotary encoder 22. These measurement values ​​are input to the LF motor control unit 33.

[0053] In order to control the rotation of the conveyance roller, the LF motor control unit 33 calculates an operation amount for the LF motor 21 for each predetermined control period based on the measurement value input from the rotary encoder processing unit 35. Then, as a control signal for the LF motor 21, a PWM signal for applying power corresponding to the calculated operation amount to the LF motor 21 is input to the LF motor driver 29.

[0054] The LF motor driver 29 drives the LF motor 21 in accordance with a control signal input from the LF motor control unit 33. Driven by this LF motor 21, the transport roller rotates, and the paper P is transported in the sub-scanning direction.

[0055] The image forming system 1 further includes a processor 3, a ROM 4, a RAM 5, an EEPROM 6, a communication interface (I / F) 7, and a user interface (I / F) 8, which are connected to the ASIC 2 via a bus 9.

[0056] The processor 3 is configured to comprehensively control each unit of the image forming system 1. The ROM 4 stores a computer program executed by the processor 3. The RAM 5 is used as a work area when the computer program is executed by the processor 3. The EEPROM 6 is an electrically rewritable non-volatile memory, and stores information that should be retained even after the image forming system 1 is turned off.

[0057] The communication interface 7 is configured to be capable of communicating with an external device such as a personal computer, etc. The user interface 8 includes an operation unit that can be operated by a user, and a display unit that can display various information to the user.

[0058] Incidentally, in the image forming system 1 of the present embodiment, if dirt 70 adheres to the linear scale 46 of the linear encoder 14, the position and speed of the carriage 12 may not be measured correctly.

[0059] 3, dirt 70 is attached to a partial area of ​​the linear scale 46. The slits 48 present in that area are covered with dirt 70. Light from the light-emitting elements 51, 52 does not reach each of the light-receiving elements 61, 62 through the slits 48 covered with dirt 70.

[0060] In this way, the stain 70 can be an obstacle to the optical sensor 47 reading the slits 48 of the linear scale 46 by emitting and receiving light. The stain 70 can be caused by the adhesion of grease, ink, paper powder, and the like to the linear scale 46.

[0061] The lower part of Fig. 3 shows an example of an encoder signal output from the optical sensor 47 when the optical sensor 47 passes at a constant speed over the dirty linear scale 46 shown in the upper part of Fig. 3. The shown encoder signal may be understood as an A-phase signal or a B-phase signal. According to this example, the edge interval of the encoder signal, which should be equal under normal circumstances, increases threefold when the optical sensor 47 passes over dirt 70.

[0062] In this embodiment, as described above, the speed of the carriage 12 is measured based on the edge spacing. Therefore, the fluctuation in the edge spacing caused by the stain 70 causes a discontinuous error in the measured value of the speed. This measurement error leads to a deterioration in the control accuracy when the speed of the carriage 12 is feedback controlled. The deterioration in control accuracy may degrade the quality of the image formed on the paper P.

[0063] When an image is formed on paper P by ejecting ink droplets from the recording head 11 while the carriage 12 is moving in the main scanning direction, the ink droplets undergo inertial motion in the main scanning direction until they land on the paper P. Therefore, the unstable speed of the carriage 12 causes deviations in the landing points of the ink droplets, deteriorating the quality of the image formed on the paper P.

[0064] Deterioration in control accuracy may cause an error in the stopping position of the carriage 12 from the target stopping point. This stopping error may affect the speed trajectory of the carriage 12 when it moves from one turning point to the next turning point during its reciprocating motion, and may cause deterioration in the quality of the image formed on the paper P. Furthermore, unstable control resulting from measurement errors may cause increased motor noise and impacts.

[0065] Therefore, in this embodiment, the presence or absence and position of an area where dirt 70 is attached is estimated, and the control method of the carriage 12 is switched depending on the presence or absence and position of the dirt 70. As described above, the area where dirt 70 is attached is an area where reading of the slit 48 and normal measurement are hindered. Therefore, the movement range of the carriage 12 where the optical sensor 47 reads the area where dirt 70 is attached is referred to as the "hindering area" hereinafter.

[0066] The inhibition region is the relative movement range of the optical sensor 47 with respect to the linear scale 46, and corresponds to the movement range of the optical sensor 47 that reads the portion of the linear scale 46 on which the stain 70, which acts as an inhibitor preventing normal reading, is attached.

[0067] In this embodiment, the optical sensor 47 reads the linear scale 46 from a position perpendicular to the surface of the linear scale 46. Therefore, the inhibition area corresponds to the movement range of the carriage 12 in which the optical sensor 47 is located in front of the area of ​​the linear scale 46 where the stain 70 is attached.

[0068] 4, which is executed by the processor 3 when the image forming system 1 is started by powering on or canceling the sleep mode. When the main process starts, the processor 3 executes a pre-scan process to estimate an inhibition region (S110).

[0069] In the pre-scan process, the processor 3 instructs the ASIC 2 to reciprocate the carriage 12 from one end of the movable range to the other end of the movable range. Based on this instruction, the CR motor control unit 32 executes drive control for the CR motor 13 to reciprocate the carriage 12 from one end of the movable range to the other end of the movable range.

[0070] In the prescan process, the CR motor 13 is controlled so that the carriage 12 moves at a constant speed, except for necessary acceleration and deceleration. This control is performed based on the deviation E=Vr-V between the target speed Vr and the measured speed value V. The measured speed value V is a measured value of the speed of the carriage 12 obtained from the linear encoder processing unit 34. A speed abnormality of the carriage 12 is detected on condition that the deviation E exceeds a threshold value in a section where the carriage 12 moves at a constant speed. In the prescan process, an inhibition area of ​​the linear scale 46 is estimated based on this speed abnormality.

[0071] An example of a method for estimating the inhibition area has already been disclosed by the applicant. For example, the position of the inhibition area is estimated based on the count value of a position counter, which is the position measurement value X of the carriage 12 measured by the linear encoder processing unit 34 when the speed abnormality of the carriage 12 is detected.

[0072] For example, when the carriage 12 is moved from a first end point of the movable range to a second end point, a first count value of the position counter from the start of the movement to when a speed abnormality is detected is detected.

[0073] Furthermore, a second count value of the position counter from the start of movement to the detection of the speed abnormality when the carriage 12 is moved from the second end point to the first end point of the movable range is detected. The inhibition area is estimated to be a main scanning direction area between a point on the linear scale 46 corresponding to the first count value when the speed abnormality is detected and a point on the linear scale 46 corresponding to the second count value when the speed abnormality is detected.

[0074] According to another example, the inhibition region may be estimated not in units of counts of the position counter, but in units of sections when the linear scale 46 is divided into a plurality of sections from one end to the other end. In this case, one or more sections including a region in the main scanning direction between the first count value and the second count value are estimated as the inhibition region.

[0075] According to yet another example, the width of the inhibition region in the main scanning direction may be estimated from the time from when the speed abnormality is detected until the speed abnormality is no longer detected and the target speed Vr. The start point and end point of the inhibition region may be estimated based on the count value of a position counter at the point where the speed abnormality begins to be detected and the width. In other words, the end point of the inhibition region may be estimated to be a point away from the start point in the main scanning direction by a distance corresponding to the width.

[0076] In other words, depending on whether the count value of the position counter when the carriage 12 is moved from one end to the other end differs from the design value, it may be determined whether the speed abnormality is caused by the adhesion of the dirt 70. Information on the inhibition area estimated in the prescan process is recorded in a register (not shown) of the ASIC 2, and shared by the CR motor control unit 32 and the linear encoder processing unit 34.

[0077] The recorded information on the inhibition area may include information on the start and end positions of the inhibition area when the carriage 12 moves in the forward direction and the start and end positions of the inhibition area when the carriage 12 moves in the backward direction. The register may record the start position and width of the inhibition area as the inhibition area information. The width of the inhibition area corresponds to the amount of change in the position counter from the point where the carriage 12 enters the inhibition area.

[0078] The estimation of the inhibition region may be performed by the linear encoder processing unit 34 in the ASIC 2, or may be performed by the processor 3 based on the first count value and the second count value obtained from the ASIC 2, etc.

[0079] After completing the pre-scan process (S110), the processor 3 determines whether or not there is an unprocessed print job (S120). The print job is received from an external device via the communication interface 7. If there is no unprocessed print job (No in S120), the processor 3 executes the process of S140.

[0080] When the processor 3 determines that an unprocessed print job exists (Yes in S120), it executes the print process shown in Fig. 5 as the print job (S130). By executing the print process, an image corresponding to the print job is formed on the paper P. The printed and processed paper P is output to a paper output tray (not shown) of the image forming system 1.

[0081] When the processor 3 ends the print process, it executes the process of S140. In S140, the processor 3 judges whether the end condition is satisfied. For example, the processor 3 judges that the end condition is satisfied when the power is shut down or when the processor 3 transitions to the sleep mode.

[0082] If it is determined that the termination condition is not satisfied (No in S140), the processor 3 returns the process to S120 and waits until an unprocessed print job occurs or the termination condition is satisfied. If it is determined that the termination condition is satisfied (Yes in S140), the main process shown in FIG. 4 is terminated.

[0083] When the processor 3 starts the printing process (see FIG. 5) in S130, it starts the paper feed process (S210). In the paper feed process, the processor 3 causes the LF motor control unit 33 to control the LF motor 21 so that a sheet of paper P is separated from a paper feed tray (not shown) and transported in the sub-scanning direction to a position where ink droplets are ejected by the recording head 11. The processor 3 further places the carriage 12, which is located at the home position, in the initial position through the control of the CR motor 13 by the CR motor control unit 32 (S220).

[0084] Thereafter, the processor 3 sets, in the CR motor control unit 32, a speed profile that defines a target speed Vr from the movement start point to the target stopping point of the carriage 12 (S230). The target speed Vr from the movement start point to the target stopping point corresponds to the target speed Vr until the carriage 12 moves from a turning point to the next turning point.

[0085] The speed profile is set in consideration of an ink ejection section in the movement path of the carriage 12 from the movement start point to the target stopping point, where the ink droplet ejection operation is performed by the recording head 11. The ink ejection section corresponds to a processing section in which the paper P is printed and processed by ejecting ink droplets.

[0086] The substance of the speed profile may be data representing the target speed Vr at each point from the start of movement to the stop as the target speed Vr from the start of movement to the target stop point. According to another example, the substance of the speed profile may be data representing the target speed Vr at each point from the start of movement to the target stop point.

[0087] In S230, a speed profile setting process shown in Figures 6 and 7, the details of which will be described later, is executed to set the speed profile. After setting the speed profile, the processor 3 executes printing in the main scanning direction (S240).

[0088] In S240, the processor 3 instructs the CR motor control unit 32 to control the CR motor 13 in accordance with the speed profile set in S230. The processor 3 further inputs image data representing an image to be formed on the paper P to the recording control unit 31, and instructs the recording control unit 31 to control the ejection operation of ink droplets by the recording head 11 based on this image data.

[0089] In response to this command, the CR motor control unit 32 controls the CR motor 13 so that the carriage 12 moves from the movement start point to the next turning point corresponding to the target stopping point along a speed trajectory that follows the set speed profile. The recording control unit 31 controls the recording head 11 so that the recording head 11 ejects ink droplets for forming an image corresponding to the image data in accordance with the movement of the carriage 12.

[0090] By executing the main scanning direction printing in S240, an image for one pass based on the image data is formed on the paper P. The image for one pass here refers to an image formed on the paper P by the ink droplet ejection operation of the recording head 11 while the carriage 12 moves in the main scanning direction from one turning point to another.

[0091] When the main scanning direction printing in S240 is completed, the processor 3 determines whether the printing process for one page of the paper P is complete (S250). If it is determined that the printing process is not complete (No in S250), the processor 3 causes the LF motor control unit 33 to control the LF motor 21 so as to transport the paper P in the sub-scanning direction by a predetermined distance corresponding to the width of the image for one pass in the sub-scanning direction (S260).

[0092] After executing the process of S260, the processor 3 sets a speed profile to be used in the next main scanning direction printing (S230). After setting the speed profile, the processor 3 executes main scanning direction printing using the speed profile (S240), thereby forming an image for one pass on the paper P that has been sent a predetermined distance in the sub scanning direction by the immediately preceding process of S260.

[0093] Processor 3 repeatedly executes the processes of S230 to S260 until it determines that printing of one page of paper P is complete, and when it determines that printing of one page of paper P is complete (Yes in S250), it executes the process of S270.

[0094] In S270, the processor 3 executes a paper discharge process for the printed paper P. In the paper discharge process, the LF motor 21 is controlled via the ASIC 2 to discharge the printed paper P onto a paper discharge tray (not shown).

[0095] Processor 3 further determines whether the print job being processed has image data for the next page (S280), and if so (Yes in S280), returns to S210 and executes page printing processing for the next page (S210-S270). In this manner, processor 3 executes page printing processing for each page, and when page printing processing for all pages is completed (No in S280), ends the printing processing.

[0096] Next, a detailed description will be given of the speed profile setting process executed by the processor 3 in S230. When the speed profile setting process shown in Fig. 6 and Fig. 7 starts, the processor 3 generates a standard speed profile (S310).

[0097] The standard speed profile is a speed profile that defines the target speed of the carriage 12 when the carriage 12 moves from the movement start point to the target stop point in the next main scanning direction printing, without taking into account the presence or absence of an obstruction area. This standard speed profile is modified depending on the presence of an obstruction area, as described below.

[0098] The standard speed profile is generated so that in an ink ejection section where the recording head 11 ejects ink droplets, the carriage 12 moves at a constant speed of a first speed Vr1 in order to shorten the movement time of the carriage 12 from the movement start point to the target stop point, and in other non-ink ejection sections, the carriage 12 moves at a high speed of a second speed Vr2 higher than the first speed Vr1 as much as possible. The first speed Vr1 is set to a speed at which the ink droplet ejection operation can be appropriately performed. The standard speed profile is set in consideration of the ink ejection section so that the ink droplet ejection operation is performed during the constant speed movement at the first speed Vr1.

[0099] In S310, the processor 3 generates a standard speed profile by executing the standard profile generation process shown in Fig. 8. When the standard speed profile generation process starts, the processor 3 first determines an ink ejection section in the movement path from the movement start point of the carriage 12 to the target stopping point in the next main scanning direction printing, where the ink droplet ejection operation is performed by the recording head 11 (S311).

[0100] Furthermore, processor 3 determines whether the distance from the end point of the ink discharge section to the target stopping point is equal to or greater than a predetermined distance required for high-speed movement (S312). If the determination in S312 is affirmative (Yes in S312), processor 3 determines in S313 whether the distance from the movement start point to the start point of the ink discharge section is equal to or greater than a predetermined distance required for high-speed movement.

[0101] If the processor 3 makes a negative determination in S313 (No in S313), it generates a first standard speed profile for realizing the target acceleration / deceleration motion exemplified in Fig. 9A as the standard speed profile (S314). Then, it ends the standard speed profile generation process shown in Fig. 8. The first standard speed profile is a speed profile with two-stage acceleration / deceleration, specifically having the following characteristics.

[0102] The acceleration section includes an acceleration section in which the carriage 12 is accelerated from the movement start point to the first velocity Vr1. The end point of the acceleration section is before the start point of the ink ejection section. The period from when the carriage 12 finishes accelerating to the first velocity Vr1 until when the carriage 12 reaches the end point of the ink ejection period includes a constant velocity period in which the carriage 12 moves at a constant speed of the first velocity Vr1. The re-acceleration section includes a re-acceleration section in which the carriage 12 is accelerated to the second velocity Vr2 immediately after the carriage 12 passes the end point of the ink ejection section. A high-speed section in which the carriage 12 moves at a constant speed at the second speed Vr2 is included from the point at which the acceleration of the carriage 12 to the second speed ends until the carriage 12 reaches the deceleration start point that is the distance before the target stopping point that is required for deceleration. The deceleration section includes a deceleration section in which the carriage 12 decelerates and stops toward the target stopping point, starting immediately after the carriage 12 reaches the deceleration start point.

[0103] As can be understood from the characteristics of the first standard speed profile, the two-stage acceleration / deceleration means acceleration / deceleration between a first speed Vr1 and a second speed Vr2.

[0104] On the other hand, if the processor 3 determines in S313 that the distance from the movement start point to the start point of the ink ejection section is equal to or greater than the predetermined distance required for high-speed movement (Yes in S313), it generates a second standard speed profile as shown in Fig. 9B as the standard speed profile (S315). Then, it ends the standard speed profile generation process shown in Fig. 8. The second standard speed profile is a two-stage acceleration / deceleration speed profile having the following characteristics:

[0105] Includes an acceleration section in which the carriage 12 accelerates from the movement start point to the second velocity Vr2. A first high-speed section is included in which the carriage 12 moves at a constant speed at the second speed Vr2 from the end of the acceleration of the carriage 12 to the second speed to a first deceleration start point before the start of the ink ejection section. The first deceleration start point is a point before the start of the ink ejection section by a distance that is predetermined so that the carriage 12 can stably run at the first speed Vr1 at the start of the ink ejection section. Includes an intermediate deceleration section in which the carriage 12 is decelerated from the first deceleration start point to the first speed Vr1. The period from when the carriage 12 finishes decelerating to the first velocity Vr1 until the carriage 12 reaches the end point of the ink ejection period includes a constant velocity period in which the carriage 12 moves at a constant velocity of the first velocity Vr1. The re-acceleration section includes a re-acceleration section in which the carriage 12 is accelerated to the second velocity Vr2 immediately after the carriage 12 passes the end point of the ink ejection section. A second high-speed section in which the carriage 12 moves at a constant speed at the second speed Vr2 is included from the point at which the acceleration of the carriage 12 to the second speed Vr2 ends until the carriage 12 reaches the deceleration start point that is the distance before the target stopping point that is required for deceleration. The deceleration section includes a deceleration section in which the carriage 12 decelerates and stops toward the target stopping point, starting immediately after the carriage 12 reaches the deceleration start point.

[0106] In addition, if processor 3 determines that the distance from the end point of the ink discharge section to the target stop point is less than the predetermined distance required for high-speed movement (No in S312), it executes the process of S317. In S317, processor 3 determines whether the distance from the movement start point to the start point of the ink discharge section is equal to or greater than the predetermined distance required for high-speed movement, similar to the process of S313.

[0107] When the processor 3 judges positive in S317 (Yes in S317), it generates a third standard speed profile for realizing the target acceleration / deceleration motion exemplified in Fig. 10A as the standard speed profile (S318). Then, it ends the standard speed profile generation process shown in Fig. 8. The third standard speed profile is a speed profile with two-stage acceleration / deceleration, specifically having the following characteristics.

[0108] Includes an acceleration section in which the carriage 12 accelerates from the movement start point to the second velocity Vr2. A high-speed section is included in which the carriage 12 moves at a constant speed at the second speed Vr2 from the end of the acceleration of the carriage 12 to the second speed to a first deceleration start point before the start of the ink ejection section. The first deceleration start point is a point before the start of the ink ejection section by a distance that is predetermined so that the carriage 12 can stably run at the first speed Vr1 at the start of the ink ejection section. Includes an intermediate deceleration section in which the carriage 12 is decelerated from the first deceleration start point to the first speed Vr1. The period from the end of deceleration to the first speed Vr1 until the carriage 12 reaches the deceleration start point that is the distance before the target stopping point that is required for deceleration, includes a constant speed section in which the carriage 12 moves at a constant speed of the first speed Vr1. The deceleration section includes a deceleration section in which the carriage 12 decelerates and stops toward the target stopping point, starting immediately after the carriage 12 reaches the deceleration start point.

[0109] In addition, when the processor 3 makes a negative judgment in S317 (No in S317), it generates a fourth standard speed profile for realizing the target acceleration / deceleration motion exemplified in Fig. 10B as the standard speed profile (S319). Then, it ends the standard speed profile generation process shown in Fig. 8. The fourth standard speed profile is a speed profile without two-stage acceleration / deceleration, specifically having the following characteristics.

[0110] The acceleration section includes an acceleration section in which the carriage 12 is accelerated from the movement start point to the first velocity Vr1. The end point of the acceleration section is before the start point of the ink ejection section. The period from when the acceleration of the carriage 12 to the first speed Vr1 ends until when the carriage 12 reaches the deceleration start point that is the distance before the target stopping point that is required for deceleration, includes a constant speed section in which the carriage 12 moves at a constant speed of the first speed Vr1. The deceleration section includes a deceleration section in which the carriage 12 decelerates and stops toward the target stopping point, starting immediately after the carriage 12 reaches the deceleration start point.

[0111] After generating the standard speed profile in S310 (see FIG. 6), the processor 3 determines whether the fine mode is specified as the print mode of the currently executed print job (S320). This determination is made in order to change the speed profile in response to the user's specification of the processing method, particularly the image quality specification. The print mode corresponds to the operation mode of the image forming system 1 related to printing.

[0112] The image forming system 1 of this embodiment has a plurality of print modes with different print image quality, and forms an image corresponding to a print job on paper P in a print mode specified by a user who registered the print job. In each print mode, the carriage 12 is transported at a constant speed of a first speed Vr1 corresponding to the print image quality in the ink ejection section.

[0113] That is, in the ink ejection section, the carriage 12 is transported at a first speed Vr1 corresponding to the print mode, and ink droplets are ejected in an ejection mode corresponding to the print mode, thereby forming an image of corresponding quality on the paper P. The standard speed profile is generated so that the carriage 12 moves at a constant speed at the first speed Vr1 corresponding to the print mode in the ink ejection section.

[0114] The above-mentioned multiple print modes include a normal mode in which an image with normal image quality is formed on paper P, and a fine mode in which a high-definition image is formed on paper P. When processor 3 determines that the fine mode is specified (Yes in S320), it executes the process of S330.

[0115] If processor 3 determines that fine mode has not been specified (No in S320), in other words, that a print mode with lower image quality than fine mode has been specified, processor 3 sets the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing, regardless of the presence or absence of an inhibition area (S390). Then, the speed profile setting process ends.

[0116] When the print mode is normal mode rather than fine mode, it is highly likely that the processing speed is more important than the image quality to the user who registered the print job. Therefore, when the print mode is normal mode, the speed profile is set to be used as the standard speed profile without modifying the speed profile to prioritize image quality over processing speed.

[0117] At S330, the processor 3 determines whether the paper P used in the print job is a specific type of paper, specifically plain paper. This determination is made in order to change the speed profile according to the type of paper P, particularly the material of the paper P. When the print job is registered, information on the paper type is input from the registration source of the print job. The processor 3 can determine the type of paper P used in the print job based on the input information on the paper type. Examples of types of paper P that can be determined include plain paper, inkjet paper, glossy paper, and photo glossy paper.

[0118] If it is determined in S330 that the paper P is plain paper, the processor 3 sets the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing, regardless of the presence or absence of an obstruction area (S390). In this manner, in this embodiment, when plain paper is used as the paper P, priority is given to the processing speed. After that, the processor 3 ends the speed profile setting process.

[0119] When the processor 3 determines that the paper P is not plain paper (No in S330), it determines whether there is a stain 70 on the linear scale 46, i.e., whether there is an inhibition area (S340). Here, it is determined whether there is an inhibition area in an intermediate section between the acceleration section from the movement start point to the transition to a constant speed state, and the deceleration section where deceleration occurs from the constant speed state to the target stopping point, which are included in the standard speed profile generated in S310.

[0120] If the processor 3 determines that there is no inhibition region (No in S340), it sets the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing (S390), and then ends the speed profile setting process.

[0121] In addition, when the processor 3 determines that an inhibition region exists (Yes in S340), it determines whether the standard speed profile generated in S310 is a second standard speed profile, which is a high-speed section separation type speed profile (S350).

[0122] If the processor 3 determines that the generated standard speed profile is the second standard speed profile (Yes in S350), it executes the processing of S400 (see FIG. 7), and if it determines that the generated standard speed profile is not the second standard speed profile (No in S350), it executes the processing of S360.

[0123] In S360, the processor 3 determines whether the inhibition region exists in an acceleration / deceleration section for the second speed. The acceleration / deceleration section for the second speed corresponds to the re-acceleration section in which the carriage 12 accelerates from the first speed Vr1 to the second speed Vr2 and the intermediate deceleration section in which the carriage 12 decelerates from the second speed Vr2 to the first speed Vr1.

[0124] If main scanning direction printing (S240) is performed based on the standard speed profile generated in S310, processor 3 makes a positive judgment in S360 if the carriage 12 is located within the inhibition area and the carriage 12 is to be speed controlled at a target speed corresponding to the re-acceleration section or the intermediate deceleration section.

[0125] For example, if the standard speed profile generated in S310 is the first standard speed profile shown in Fig. 9A and the inhibition region is in region R11 shown in Fig. 9A, the processor 3 makes a positive determination in S360. If the inhibition region is in region R12 in the constant speed section or region R13 in the high speed section shown in Fig. 9A, the processor 3 makes a negative determination in S360.

[0126] For example, if the standard speed profile generated in S310 is the third standard speed profile shown in Fig. 10A and the inhibition region is in region R31 shown in Fig. 10A, the processor 3 makes a positive determination in S360. If the inhibition region is in region R32 in the constant speed section or region R33 in the high speed section shown in Fig. 10A, the processor 3 makes a negative determination in S360.

[0127] When it is determined that the inhibition region exists in the acceleration / deceleration section for the second speed (Yes in S360), the processor 3 modifies the generated standard speed profile so as to delete the high-speed section from the standard speed profile (S370). That is, the generated standard speed profile is modified to a speed profile having the same shape as the fourth standard speed profile (see FIG. 10B) without two-stage acceleration / deceleration. In other words, the speed profile is modified so that the carriage 12 does not move at high speed even in the non-ink ejection section.

[0128] For example, if the standard speed profile generated in S310 is the first standard speed profile shown in Figure 9A, the standard speed profile is modified as shown in Figure 11 by removing the re-acceleration section and the high-speed section (the dashed line portion shown in Figure 11) after passing the ink ejection section, so that even after passing the ink ejection section, the carriage 12 moves at the first speed Vr1 until it passes the deceleration start point just before the target stopping point, and then the carriage 12 decelerates from the deceleration start point toward the target stopping point.

[0129] Processor 3 then sets the corrected speed profile as the speed profile to be used in the next main scanning direction printing (S380). As a result, when processor 3 determines that the inhibition region exists in the acceleration / deceleration section for the second speed, in the next main scanning direction printing, a control method is adopted in which carriage 12 is moved without two-stage acceleration / deceleration in order to suppress the influence of control error of carriage 12 due to measurement error in the inhibition region.

[0130] In addition, if the processor 3 determines in S360 that the inhibition area does not exist in the acceleration / deceleration section for the second speed (No in S360), it sets the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing (S390), regardless of the presence or absence of the inhibition area in other sections. Then, the speed profile setting process ends.

[0131] In S400 (see FIG. 7), the processor 3 determines whether the inhibition region exists in the intermediate deceleration section from the second speed Vr2 to the first speed Vr1. When the inhibition region exists in the region R21 shown in FIG. 9B, the processor 3 makes a positive determination in S400.

[0132] When it is determined that the inhibition area exists in the intermediate deceleration section (Yes in S400), the processor 3 modifies the standard speed profile generated above by deleting the first high speed section from the standard speed profile and replacing the non-ink ejection section preceding the ink ejection section with a constant speed section at the first speed Vr1 (S410).

[0133] In Fig. 12A, an example of the standard speed profile before correction is indicated by a dashed line, and an example of the speed profile after correction by the processing in S410 is indicated by a solid line. That is, the processor 3 corrects the generated standard speed profile to a speed profile having the same shape as the first standard speed profile shown in Fig. 9A. After correcting the standard speed profile in S410, the processor 3 executes the processing of S420.

[0134] When it is determined that the inhibition region does not exist in the intermediate deceleration region (No in S400), the processor 3 executes the process of S420 without modifying the standard speed profile. In S420, the processor 3 determines whether the inhibition region exists in the re-acceleration section from the first speed Vr1 to the second speed Vr2. When the inhibition region exists in the region R22 shown in FIG. 9B, the processor 3 makes an affirmative determination in S420.

[0135] If it is determined that the inhibition region does not exist in the re-acceleration section (No in S420), the processor 3 executes the process of S440. If it is determined that the inhibition region exists in the re-acceleration section (Yes in S420), the processor 3 corrects the speed profile in S430 and then executes the process of S440.

[0136] In S430, the processor 3 deletes the second high-speed section from the standard speed profile generated in S310 or the speed profile after the correction in S410, and corrects the standard speed profile so as to replace the non-ink ejection section following the ink ejection section with a constant speed section at the first speed Vr1 (S430).

[0137] In Fig. 12B, an example of the standard speed profile before correction is shown by a dashed line, and an example of the speed profile after correction by the processing in S430 is shown by a solid line. When the standard speed profile is subjected to both the corrections in S410 and S430, it is corrected to a speed profile having the same shape as the fourth standard speed profile without two-stage acceleration / deceleration shown in Fig. 10B.

[0138] In S440, if the standard speed profile has been modified by one or both of the processes of S410 and S430, the processor 3 sets the modified speed profile as the speed profile to be used in the next main scanning direction printing. If not modified, the processor 3 sets the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing, and ends the speed profile setting process shown in Figures 6 and 7.

[0139] The above-mentioned speed profile setting process sets a speed profile according to the presence and position of an obstruction area in the intermediate section between the acceleration section from the movement start point to the constant speed state and the deceleration section from the constant speed state to the target stopping point, and in the subsequent main scanning direction printing, movement control of the carriage 12 is executed based on this speed profile. If an obstruction area falls within the acceleration / deceleration section for the second speed, the corresponding two-stage acceleration / deceleration is stopped, and deterioration of movement control of the carriage 12 due to the presence of the obstruction area is suppressed.

[0140] Next, the details of the motor control process executed by the CR motor control unit 32 for the speed control of the carriage 12 based on the speed profile will be described with reference to Fig. 13. Upon receiving a command from the processor 3 in S240, the CR motor control unit 32 executes the motor control process shown in Fig. 13 at every predetermined control period until the carriage 12 is moved to the turning point according to the set speed profile.

[0141] In the motor control process for each control period, the CR motor control unit 32 determines whether the carriage 12 is located within the inhibition area based on the position measurement value X of the carriage 12 input from the linear encoder processing unit 34 (S510).

[0142] If it is determined that the carriage 12 is not located within the inhibition area (No in S510), the CR motor control unit 32 calculates the deviation E = Vr - V between the speed measurement value V of the carriage 12 input from the linear encoder processing unit 34 and the target speed Vr according to the speed profile, and calculates the feedback control amount Ufb based on the deviation E (S520).

[0143] The CR motor control unit 32 inputs the deviation E to a predetermined transfer function to calculate a feedback operation amount Ufb for reducing the deviation E. The CR motor control unit 32 may calculate the feedback operation amount Ufb corresponding to the deviation E by a PID control method.

[0144] The CR motor control unit 32 determines the calculated feedback operation amount Ufb as the operation amount U for the CR motor 13. After that, the CR motor control unit 32 inputs a control signal for realizing the operation amount U to the CR motor driver 19 (S530). As a result, the CR motor driver 19 drives the CR motor 13 with a drive power (specifically, a drive voltage or a drive current) corresponding to the determined operation amount U.

[0145] In this way, when the carriage 12 is positioned outside the inhibition area, the CR motor control unit 32 controls the speed of the carriage 12 by feedback control based on the deviation E=Vr-V between the speed measurement value V and the target speed Vr.

[0146] On the other hand, when the CR motor control unit 32 determines that the carriage 12 is located within the inhibition area (Yes in S510), it executes the process of S550. In S550, the CR motor control unit 32 calculates the feedforward operation amount Uff corresponding to the target speed Vr without using the speed measurement value V. For example, the feedforward operation amount Uff is obtained by inputting the target speed Vr according to the speed profile to a transfer function that is predetermined based on the equation of motion of the carriage 12.

[0147] When the carriage 12 moves at a constant speed, the reaction force acting on the carriage 12 and the CR motor 13 is basically a reaction force caused by viscous friction. The viscous friction is proportional to the speed of the carriage 12.

[0148] Therefore, the feedforward manipulated variable Uff in the section where the carriage 12 moves at a constant speed can be determined as the value K·Vr obtained by multiplying the target speed Vr according to the speed profile by a coefficient K corresponding to viscous friction.

[0149] The CR motor control unit 32 determines the feedforward operation amount Uff calculated in this manner as the operation amount U for the CR motor 13. Thereafter, the CR motor control unit 32 inputs a control signal for realizing the above-mentioned determined operation amount U to the CR motor driver 19 (S560). This causes the CR motor driver 19 to drive the CR motor 13 with drive power corresponding to the above-mentioned determined operation amount U.

[0150] That is, when the carriage 12 is located within the inhibition area, the CR motor control unit 32 performs feedforward control based on the speed profile, and in other cases, performs feedback control based on the speed profile.

[0151] As another example, the CR motor control unit 32 may perform feedback control based on the deviation E in the inhibition area as well as outside the inhibition area. In this case, since the reliability of the speed measurement value V is low, the speed measurement value V used to calculate the deviation E is corrected to obtain the corrected speed measurement value V * Deviation E=Vr-V based on * The feedback control amount Ufb can be calculated from the corrected speed measurement value V * may be, for example, a moving average of the velocity measurements V.

[0152] Depending on whether the inhibition area is in the acceleration section from the starting point of movement or in the deceleration section toward the target stopping point, or in the intermediate section between the acceleration section and the deceleration section, the control in the inhibition area may be performed using either feedback control or feedforward control.

[0153] For example, when an inhibition area exists outside the intermediate section, the CR motor control unit 32 adjusts the corrected speed measurement value V * In addition, if there is an inhibition region in the intermediate section, a feedforward control may be performed.

[0154] According to this embodiment, the inhibition area existing in the intermediate section is basically located in the constant speed section or the high speed section (including the first and second high speed sections) where the carriage 12 is controlled to a constant speed by the above-mentioned speed profile correction. Therefore, the corrected speed measurement value V * Whether feedback control based on the above is executed or feedforward control is executed, it is possible to realize stable speed control compared to the case where acceleration control or deceleration control is executed in the inhibition region.

[0155] In addition, in order to suppress the influence of measurement errors due to the presence of an inhibition area, the linear encoder processing unit 34 can repeatedly execute a correction process shown in Fig. 14, in addition to the process of calculating the measurement values ​​of the position and speed of the carriage 12 based on the encoder signal. The correction process is performed to remove errors contained in the position measurement value X of the carriage 12, which is measured as the count value of the position counter when passing through an inhibition area.

[0156] When the correction process is started, the linear encoder processing unit 34 waits until the carriage 12 passes through the inhibition area (S610). The passage here means that the carriage 12 passes through the end point of the inhibition area, which is the end point of the inhibition area on the side of the traveling direction of the carriage 12.

[0157] Whether or not the carriage 12 has passed through the inhibition zone can be determined based on the position measurement value X of the carriage 12 when the carriage 12 enters the inhibition zone, the width of the inhibition zone, and the distance traveled by the carriage 12 after entering the inhibition zone. The distance traveled can be calculated as a time integral of the target speed Vr, based on the target speed Vr of the carriage 12 and the elapsed time after entering the inhibition zone.

[0158] When the linear encoder processing unit 34 determines that the carriage 12 has passed through the inhibition area (Yes in S610), it corrects the error in the count value of the position counter that has occurred in the inhibition area (S620).

[0159] For example, the linear encoder processor 34 can calculate the difference (D1-D2) between the travel distance D1 (converted into a count value) of the carriage 12 calculated as the time integral of the target speed Vr from the point in time when the carriage 12 enters the inhibition area and the deviation D2 of the count value of the position counter from the point in time when the carriage 12 is determined to have passed through the inhibition area, as the count value error caused by the stain 70. The linear encoder processor 34 can correct the count value by adding the difference (D1-D2) so that the deviation D2 matches the travel distance D1.

[0160] According to another example, the linear encoder processing unit 34 determines an error in the count value of the position counter that occurs in the inhibition region during prescanning, and corrects the count value by the determined error, thereby correcting the error.

[0161] According to the image forming system 1 of this embodiment described above, different types of speed profiles are set depending on the presence and position of an inhibition area, and thereby, speed control of the carriage 12 based on a speed profile with two-stage acceleration / deceleration as a first control method, or speed control of the carriage 12 based on a speed profile without two-stage acceleration / deceleration as a second control method is executed.

[0162] According to the first control method, the carriage 12 is controlled to move at a constant speed of a first speed Vr1 corresponding to the print mode in the ink ejection section, and at a constant speed of a second speed Vr2 that is at least partially higher than the first speed Vr1 in the non-ink ejection section. According to the second control method, the carriage 12 is controlled to move at a constant speed of the first speed Vr1 in both the ink ejection section and the non-ink ejection section.

[0163] According to this embodiment, when the inhibition area is in the acceleration / deceleration area for the second speed Vr2, which is a specific area, the corresponding two-stage acceleration / deceleration is stopped and the speed profile is modified so that the carriage 12 passes through the inhibition area during constant speed control at the first speed Vr1.

[0164] The speed control of the carriage 12 at a constant speed is more stable than the control at the time of acceleration / deceleration. At a constant speed, even if the speed of the carriage 12 cannot be measured correctly temporarily, the carriage 12 can be moved at a constant speed in a relatively stable manner by controlling the CR motor 13 based on a constant operation amount, for example.

[0165] Therefore, as in this embodiment, by modifying the speed profile so that acceleration / deceleration to the second speed Vr2 is not performed in the inhibition region, it is possible to prevent measurement errors in the inhibition region from having an undesirable effect on control accuracy or control stability, and it is possible to move the carriage 12 at an appropriately high speed.

[0166] Such transportation of the carriage 12 taking into consideration the inhibition area can improve the throughput of the printing process in the image forming system 1 while suppressing the influence of image quality degradation. In particular, according to this embodiment, it is possible to move the carriage 12 at a high speed, regardless of the position of the inhibition area, compared to a case where high-speed movement is stopped only because of the presence of an inhibition area. For example, in this embodiment, a method of partially stopping high-speed movement is adopted when correcting a high-speed section separation type speed profile due to the presence of an inhibition area, so that it is possible to efficiently move the carriage 12 at high speed. Therefore, according to this embodiment, it is possible to provide a user with a highly convenient image forming system 1.

[0167] [Variations] Next, a modified image forming system 1 will be described. However, the image forming system 1 of the modified example differs from the above-mentioned embodiment only in a part of the speed profile setting process executed by the processor 3 in S230. Therefore, in the following, only the parts of the speed profile setting process executed by the processor 3 that are different from the above-mentioned embodiment will be selectively described, and the description of the other parts having the same configuration as the above-mentioned embodiment will be omitted.

[0168] 6, when the processor 3 determines that an inhibition region exists in the acceleration / deceleration region for the second speed (Yes at S360), the processor 3 executes the process of S375 shown in Fig. 15 instead of the process of S370. At S375, the processor 3 modifies the standard speed profile generated at S310 so as to extend the constant speed region in the standard speed profile to the end point of the inhibition region, and set the inhibition region in the constant speed region.

[0169] When the standard speed profile generated in S310 is the first standard speed profile shown in FIG. 9A, processor 3 extends the constant speed section so as to delay the start of the re-acceleration section to a point immediately after passing through region R50, which is the inhibition region, as shown in FIG. 16A.

[0170] As a result, the processor 3 corrects the standard speed profile so that the carriage 12 moves at a constant speed at the first speed Vr1 in the adjacent section up to the inhibition area even in the non-ink ejection section adjacent to the ink ejection section. The dashed dotted line in Fig. 16A indicates the standard speed profile before correction, and the solid line indicates the speed profile after correction by extending the constant speed section.

[0171] When the standard speed profile generated in S310 is the third standard speed profile shown in FIG. 10A, processor 3 extends the constant speed section so as to advance the start point of the constant speed section to a point before entering region R60, which is the inhibition region, as shown in FIG. 16B.

[0172] As a result, the processor 3 corrects the standard speed profile so that the carriage 12 moves at a constant speed of the first speed Vr1 in a section including an inhibition region of an adjacent non-ink ejection section preceding the ink ejection section. The dashed line shown in Fig. 16B, like the dashed line shown in Fig. 16A, indicates the standard speed profile before correction due to the extension of the constant speed section.

[0173] In the next S380, the processor 3 sets the speed profile corrected in the process of S375 as the speed profile to be used in the next main scanning direction printing, and then ends the speed profile setting process (S230).

[0174] When the processor 3 determines that the standard speed profile generated in S310 is the second standard speed profile, the processor 3 executes the process of S415 (see FIG. 7) instead of the process of S410 to advance the start point of the constant speed section to a point before entering the inhibition region R70, as shown in FIG. 17A. In this way, the processor 3 modifies the standard speed profile so as to extend the constant speed section to at least the start point of the inhibition region (S415).

[0175] Similarly, processor 3 executes the process of S435 (see FIG. 7) instead of the process of S430, thereby delaying the start of the re-acceleration section to the point immediately after passing through region R80, which is an inhibition region, as shown in FIG. 17B. In this way, processor 3 modifies the standard speed profile so as to extend the constant speed section at least to the end point of the inhibition region (S435).

[0176] In S440 (see FIG. 7), processor 3 sets the speed profile corrected in S415 or S435 as the speed profile to be used in the next main scanning direction printing. In this manner, in the modified example, when an inhibition region exists in the acceleration / deceleration region for the second speed in the standard speed profile generated in S310, the two-stage acceleration / deceleration is not stopped, but the start point and / or end point of the constant speed section is extended to include the inhibition region.

[0177] Therefore, in this modified example, it is possible to improve the throughput of the printing process by moving the carriage 12 at high speed while suppressing the undesirable effects of two-stage acceleration / deceleration being performed in the inhibition area.

[0178] Although the exemplary embodiment of the present disclosure has been described above, it goes without saying that the present disclosure is not limited to the above-mentioned embodiment and can take various forms. For example, if an inhibition area exists, the processor 3 may operate to set a speed profile without two-stage acceleration / deceleration to the CR motor control unit 32 regardless of the position of the inhibition area.

[0179] For example, if the processor 3 judges negative in the process of S340, it may set the standard speed profile generated in S310 as the speed profile to be used in the next main scanning direction printing, and if the processor 3 judges positive in the process of S340, it may operate to set a speed profile without two-stage acceleration / deceleration for the CR motor control unit 32 by executing the process of S370 without executing the processes of S350 and S360.

[0180] The processor 3 may be operable in S340 to make a positive determination that an inhibition region exists when the inhibition region exists in a section in which the target speed Vr in the standard speed profile is set to a speed that exceeds the first speed Vr.

[0181] For example, in S340, processor 3 may treat a non-constant speed section in a high-speed range, in which a target speed Vr exceeding the first speed Vr1 is set, among the acceleration section from the start point of movement and the deceleration section to the target stopping point, as equivalent to the above-mentioned intermediate section, and determine whether or not there is an inhibition area in the non-constant speed section.

[0182] When an inhibition region exists in the non-constant speed section of the high speed range, a positive determination is made in S360, and the speed profile may be modified so as to delete the corresponding high speed section and replace the inhibition region with a constant speed section of the first speed Vr1 (S370). In other words, the non-constant speed section of the high speed range exceeding the first speed Vr1 may be treated in the same way as the intermediate deceleration section and re-acceleration section described above, and the standard speed profile may be modified.

[0183] In addition, the technology disclosed herein can be applied to various systems in which the movement of a processing head that performs a specified processing on an object is realized by motor control using an encoder, not just to an image forming system 1 that forms an image on paper P.

[0184] For example, the technology disclosed herein is applicable not only to inkjet printers but also to other serial printers and garment printers. The technology disclosed herein can also be applied to machine tools such as machines that print wiring patterns. The technology disclosed herein is not limited to systems that process objects, but can be applied to various systems that transport moving objects by controlling a motor using an encoder.

[0185] As an encoder for measuring the position and speed, an encoder other than the above-mentioned transmission-type linear encoder 14 may be used. For example, a reflection-type linear encoder may be used that receives light from a light-emitting element reflected by an encoder scale and reads the encoder scale.

[0186] When an encoder is used in which an optical sensor reads the encoder scale from an angle, such as a reflective linear encoder, the "inhibition area" may be the range of movement of the optical sensor when it moves over an area shifted from the front by a distance depending on the reading angle, rather than directly in front of the dirty area on the encoder scale.

[0187] The technology disclosed herein can also be applied to a control system using a rotary encoder. Known types of encoders include an encoder in which the sensor moves relative to a fixed encoder scale, causing the sensor to move relative to the encoder scale, and an encoder in which the encoder scale moves relative to a fixed sensor, causing the sensor to move relative to the encoder scale. The technology disclosed herein can be applied to a control system using either of these encoders.

[0188] The functions of one component in the above embodiment may be distributed among multiple components. The functions of multiple components may be integrated into one component. For example, the controller may not be configured with the processor 3 and the ASIC 2, but may be configured with one or more processors without an ASIC, may be configured with one or more ASICs without a processor, or may be configured with a combination of one or more processors and one or more ASICs. One or more components of the controller including at least one of a processor and an ASIC can cooperate with each other to execute the processing related to the controller of the present disclosure.

[0189] In addition, some of the configurations of the embodiments may be omitted. All aspects included in the technical ideas specified by the wording of the claims are embodiments of the present disclosure. [Explanation of symbols]

[0190] 1...image forming system, 2...ASIC, 3...processor, 4...ROM, 5...RAM, 6...EEPROM, 7...communication interface, 8...user interface, 9...bus, 11...recording head, 12...carriage, 13...CR motor, 14...linear encoder, 15...printing mechanism, 18...head driver, 19...CR motor driver, 21...LF motor, 22...rotary encoder, 29...LF motor driver, 31...recording control unit, 32...CR motor control unit, 33...LF motor control unit, 34...linear encoder processing unit, 35...rotary encoder processing unit, 41...guide shaft, 42...endless belt, 43...driving pulley, 44...driven pulley, 46...linear scale, 47...optical sensor, 48...slit, 50...light emitting unit, 51,52...light emitting element, 60...light receiving unit, 61,62...light receiving element, P...paper.

Claims

1. A motor; a moving body configured to be driven by the motor to move along a passage and process an object; an encoder including an encoder scale and a sensor configured to move relative to the encoder scale in conjunction with the movable body and to output an encoder signal based on reading of the encoder scale; a measuring instrument that measures a state quantity representing a moving state of the moving object on the passage based on the encoder signal; a controller configured to control the motor based on the measured state quantity, thereby controlling movement of the moving body; Equipped with a movement path of the moving body from the movement start point to the stop point includes an acceleration section in which the moving body transitions from the movement start point to a constant speed state, a deceleration section in which the moving body transitions from the constant speed state to a stop point, and an intermediate section between the acceleration section and the deceleration section, and the intermediate section includes a processing section in which the moving body processes the object; The controller: determining whether or not a portion of the encoder scale to which an obstruction that obstructs normal reading of the encoder scale by the sensor is attached is within the intermediate section of an obstruction area, which is a movement area of ​​the movable body read by the sensor; selecting one of a plurality of control methods including a first control method and a second control method according to the presence or absence of the determined inhibition area, and controlling the movement of the moving object on the movement path with the selected control method; The first control method is a method for controlling the movement of the moving body so that, in the processing section of the intermediate section, the moving body is moved at a constant speed of a first speed, and in the non-processing section, which is a section of the intermediate section other than the processing section, the moving body is moved at least partially at a constant speed of a second speed that is higher than the first speed, and is selected when it is determined that the inhibition area does not exist; The second control method is a method of controlling the movement of the moving body so as to move the moving body at a constant speed of the first speed in the processing section and the non-processing section, and is a control system that is selected when it is determined that the inhibition area exists.

2. Determining the presence or absence of the inhibition area includes determining the presence or absence of the inhibition area in a specific section within the intermediate section, in which the moving object moves at a non-constant speed between the first speed and the second speed when the movement of the moving object is controlled by the first control method, The control system of claim 1, wherein when the controller determines that there is an inhibition area in the specific section, the controller selects the second control method and controls the movement of the moving body using the second control method, and when the controller determines that there is no inhibition area in the specific section, the controller selects the first control method and controls the movement of the moving body using the first control method, regardless of whether there is an inhibition area outside the specific section in the intermediate section.

3. Determining the presence or absence of the inhibition area includes, when the intermediate area has first and second non-processing areas separated by the processing area as the non-processing areas, determining the presence or absence of the inhibition area in, as the specific area, a first non-constant speed area which is a section within the first non-processing area in which the moving body moves at a non-constant speed when the movement of the moving body is controlled by the first control method, and a second non-constant speed area which is a section within the second non-processing area in which the moving body moves at a non-constant speed; When the controller determines that the inhibition area exists in both the first non-constant speed section and the second non-constant speed section, the controller controls the movement of the moving body using the second control method; when the controller determines that the inhibition area does not exist in the second non-constant speed section and the inhibition area exists in the first non-constant speed section, the controller controls the movement of the moving body using a third control method instead of the second control method; when the controller determines that the inhibition area does not exist in the first non-constant speed section and the inhibition area exists in the second non-constant speed section, the controller controls the movement of the moving body using a fourth control method; the third control method is a method of controlling the movement of the moving body so that, in the intermediate section, in the processing section and the first non-processing section adjacent to the processing section, the moving body is moved at a constant speed at the first speed, and in the second non-processing section, the moving body is moved at least partially at a constant speed at the second speed; The control system of claim 2, wherein the fourth control method is a method of controlling the movement of the moving body so that in the processing section and the second non-processing section adjacent to the processing section of the intermediate section, the moving body is moved at a constant speed at the first speed, and in the first non-processing section, the moving body is moved at a constant speed at least partially at the second speed.

4. A motor; a moving body configured to be driven by the motor to move along a passage and process an object; an encoder including an encoder scale and a sensor configured to move relative to the encoder scale in conjunction with the movable body and to output an encoder signal based on reading of the encoder scale; a measuring instrument that measures a state quantity representing a moving state of the moving object on the passage based on the encoder signal; a controller configured to control the motor based on the measured state quantity, thereby controlling movement of the moving body; Equipped with a movement path of the moving body from the movement start point to the stop point includes an acceleration section in which the moving body transitions from the movement start point to a constant speed state, a deceleration section in which the moving body transitions from the constant speed state to a stop point, and an intermediate section between the acceleration section and the deceleration section, and the intermediate section includes a processing section in which the moving body processes the object; The controller: determining whether or not a portion of the encoder scale to which an obstruction that obstructs normal reading of the encoder scale by the sensor is attached is present in a non-machining section that is a section other than the machining section within the intermediate section of an obstruction area that is a movement area of ​​the movable body read by the sensor; selecting one of a plurality of control methods including a first control method and a second control method according to the presence or absence of the determined inhibition area, and controlling the movement of the moving object on the movement path with the selected control method; the first control method is a method for controlling the movement of the moving body such that, in the processing section of the intermediate section, the moving body is moved at a constant speed of a first speed, and, in the non-processing section of the intermediate section, the moving body is moved at least partially at a constant speed of a second speed that is higher than the first speed, and is selected when it is determined that the inhibition area does not exist; The second control method is a method of controlling the movement of the moving body so that in the processing adjacent section, which is the processing section and a section of the intermediate section adjacent to the processing section and which includes the inhibition area, the moving body is moved at a constant speed at the first speed, and in the non-processing section excluding the processing adjacent section, the moving body is moved at a constant speed at least partially at the second speed, and is a control system that is selected when it is determined that the inhibition area exists.

5. Determining the presence or absence of the inhibition region includes determining the presence or absence of the inhibition region in a specific section within the non-processing section, in which the moving body moves at a non-constant speed between the first speed and the second speed when the movement of the moving body is controlled by the first control method, The control system according to claim 4 , wherein the first control method is selected when it is determined that the inhibition area is not in the specific section, and the second control method is selected when it is determined that the inhibition area is in the specific section.

6. The controller: a first operation mode in which one of the plurality of control methods is selected according to the presence or absence of the inhibition area determined, and the movement of the moving object is controlled by the selected control method; a second operation mode in which the movement of the moving object is controlled by the first control method regardless of the presence or absence of the inhibition area; The control system according to any one of claims 1 to 5, further comprising: a control unit for controlling movement of the moving object in an operation mode selected from the first operation mode and the second operation mode in accordance with a user's designation.

7. The controller: a first operation mode in which one of the plurality of control methods is selected according to the presence or absence of the inhibition area determined, and the movement of the moving object is controlled by the selected control method; a second operation mode in which the movement of the moving object is controlled by the first control method regardless of the presence or absence of the inhibition area; and controlling the movement of the moving body in an operation mode corresponding to a material or a processing method of the object, out of the first operation mode and the second operation mode.

8. the movable body is configured to mount an ejection head configured to eject ink droplets, and to execute an operation of forming an image on the object as a processing operation on the object by ejecting the ink droplets from the ejection head; The control system described in claim 6, wherein when the user specifies a first image quality as the specification, the controller controls the movement of the moving body in the first operating mode, and when the user specifies a second image quality lower than the first image quality, the controller controls the movement of the moving body in the second operating mode, and in the processing section, controls the ejection of ink droplets by the ejection head, thereby controlling the movement of the moving body and the ejection of the ink droplets so that the image is formed on the object with the specified image quality.

9. The measuring device measures at least a speed of the moving object as the state quantity, The control system according to any one of claims 1 to 8, wherein the controller sets a speed profile that defines a target speed of the moving body from the start point of movement of the moving body to a target stopping point of the moving body prior to controlling the movement of the moving body from the start point of movement of the moving body, and after starting to control the movement, feedback controls the speed of the moving body based on a deviation between the speed of the moving body measured by the measuring instrument and the target speed according to the speed profile.

10. The control system described in claim 9, wherein the controller feedback controls the speed of the moving body by driving the motor with an operation amount corresponding to the deviation outside the inhibition zone, but drives the motor with a predetermined operation amount corresponding to the target speed in the inhibition zone that is not dependent on the deviation within the inhibition zone.

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