JP2016112881A - Printing device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new procedure capable of approaching to the utmost to a target print gap regardless of a device, by reducing an influence of a component tolerance or an assembly error carried by each device.SOLUTION: In a printing device including a moving mechanism for changing a distance of a print gap, a drive amount corresponding to a target value of a distance is obtained on reference to data in a storage part storing beforehand correlation data between a drive amount of the moving mechanism inherent in the device and a distance, and the moving mechanism is driven.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a printing apparatus capable of changing a distance between a print head and a platen.

  Some inkjet printing apparatuses have a mechanism for changing the distance between a print head and a platen (hereinafter referred to as a print gap). In order to make the ink landing position accurate, the smaller the error between the set value and the actual print gap, the better.

  Patent Document 1 discloses a method for determining whether or not the print gap associated with the assembly position of the constituent members of the apparatus falls within the design reference range without using a dedicated mechanism.

JP 2009-160805 A

  As one of the error factors of the print gap, there are part tolerance and assembly error of the print head and parts for mounting the print head. Errors may also occur due to transportation of the printing apparatus, parts replacement, parts wear, and the like. Since these factors are different for each apparatus, each apparatus has a strictly different print gap. Conventionally, the distance between the print head and the platen is usually set wider in consideration of safety and the worst of errors.

  The present invention has been made in view of the above-described problems. An object of the present invention is to provide a new technique that can reduce the influence of component tolerances and assembly errors that differ from device to device and can be as close as possible to the target print gap regardless of the device. Further objects of the present invention will be clarified in the following description of embodiments.

  One aspect of the present invention is a printing apparatus that includes a print head, a platen provided to face the print head, and a moving mechanism that changes a distance between the print head and the platen. A storage unit that stores unique correlation data between the driving amount of the moving mechanism and the distance in advance, and the correlation data stored in the storage unit correspond to the target value of the distance. And a controller that obtains the driving amount and drives the moving mechanism.

  According to the present invention, the distance of the print gap between the print head and the platen can be made variable. Can be as close as possible to the print gap.

Cross-sectional view showing overall configuration of inkjet printer (A) is a cross-sectional view showing the configuration of the print unit in the first embodiment, and (b) is a cross-sectional view in the second embodiment. (A) is the cross-sectional view which looked at the structure of the printing part in a 1st form from another direction, (b) is the cross-sectional view in a 2nd form Lift cam shape and cam diagram Control system block diagram (A) is a figure which shows the state which has mounted the carriage of the unit state on the adjustment tool in 1st form, (b) is a figure which shows the state in 2nd form. Data table showing the correlation between lift cam angle, print gap, and sensor light reception Graph showing the correlation between lift cam angle, print gap, and sensor light reception Diagram for explaining error correction of platen height eigenvalue The flowchart figure which shows the error correction sequence of the platen height eigenvalue Graph showing the relationship between lift cam profile and modified lift cam profile Flowchart diagram showing the initial calibration sequence A graph showing the modified lift cam profile before and after the update Flowchart diagram showing the calibration sequence corresponding to component wear Flowchart diagram showing the profile update sequence when the unit is replaced

  A printing apparatus according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing an outline of the overall configuration of the inkjet printing apparatus.

  A roll sheet 100 in which a long sheet is wound in a roll shape as a recording medium is set at the lower part of the printing apparatus. The sheet 101 pulled out from the roll sheet 100 is conveyed by a conveyance roller group including a conveyance roller 103. The printing unit 106 prints an image on the conveyed sheet 101. The print unit 106 includes a print head 104, a carriage 105 that reciprocates on the print head 104, and a platen 107. The print head 104 performs recording by ejecting ink from nozzles (recording elements) by an inkjet method. The element for applying energy for ejecting ink by the ink jet method may be in any form such as a heating element, a piezo element, a MEMS element, and an electrostatic element. The printing system is a serial scanning system in which one image is formed by alternately repeating a printing operation for forming one band while scanning the carriage in the main scanning direction and a step feeding operation for the sheet in the sub-scanning direction. . The sheet 101 is cut by the cutter unit 108 after an image is printed by the printing unit 106. The cut sheet 102 is received by being dropped into the basket-like accommodation portion 109 by gravity.

  A main body controller 131 to be described later is provided in the main body of the printing apparatus. An operation panel 200 having a user interface for a user to operate the apparatus is provided on the exterior of the printing apparatus.

  FIG. 2A is a cross-sectional view showing a configuration around the carriage 105 in the print unit 106 of the first embodiment, and FIG. 3A is a cross-sectional view of the configuration of the first embodiment viewed from another direction. . FIG. 2B is a cross-sectional view showing the configuration of the second form in which a part of the first form is changed, and FIG. 3B is a cross-sectional view of the second form as viewed from another direction. FIG. 3 shows a state where the carriage 105 is at the home position (one end portion of the reciprocating movement).

  A platen patch 133 (a reference member for measurement) is embedded on the surface of the platen 107 for calibration described later. Ink is ejected from the print head 104 while the carriage 105 reciprocates with respect to the sheet 101 on the platen 107. The carriage 105 is supported by the two guide rails 112 and 113, and is reciprocated along the direction in which the guide rail extends (main scanning direction) when a driving force is applied by the carriage motor 110 and the driving belt 111. A multi-sensor 122 that detects the end of the sheet and the distance to the sheet is attached to the side surface of the carriage 105. The multisensor 122 includes a light source and a light receiver, and performs optical sensing. Both the multi-sensor 122 and the print head 104 are provided without being displaced relative to the carriage 105. Therefore, if the distance from the sensor to the platen is measured by the multi-sensor 122, the distance of the print gap from the nozzle surface of the print head 104 to the platen can be detected. Details will be described later.

  Since the sheet is supported on the platen during the actual printing operation, the actual gap distance between the nozzle surface of the print head and the sheet surface is the actual thickness, but the thickness of the sheet is known by the sheet type, so it is expected. To set the print gap.

  A carriage controller 132 is mounted on the carriage 105. The carriage controller 132 is a local electric circuit board having a storage unit for information indicating individual differences between carriages. The carriage controller 132 is connected to a main body controller 131 built in the printing apparatus main body by a flexible cable.

  Both the first form in FIG. 2A and the second form in FIG. 2B have a moving mechanism that arbitrarily changes the distance of the print gap in a stepless manner or in multiple steps. The print gap changes when a part of the carriage 105 moves up and down (gravity direction). Hereinafter, this moving mechanism and operation will be described.

  2A and 3A, the carriage 105 includes a front structure 114 on which the print head 104 is mounted and a rear structure 115 connected to a part of the drive belt 111. Divided into two. The front structure 114 is connected and integrated via a lift shaft 116 and two lift cams 117 so as to be able to be displaced relative to the rear structure 115 in the direction of the print gap (the direction of gravity). ing. A lift coupling 118 is provided at one end of the lift shaft 116.

  In the second form of FIG. 2B and FIG. 3B, the front structure 114 and the rear structure 115 are separated. In the moving mechanism, two lift cams 117 are provided on both sides of the carriage, and these two cams are fixed to the same shaft and rotate integrally. This idea is the same as in the first embodiment. The feature of the second embodiment is a structure in which lift cam support members 150 (two places) and rotation restricting members 151 (one place) are provided and the positions of these can be adjusted with high accuracy.

  L-shaped lift cam support members 150 are coupled to the rear structure 115 at two positions on both sides of the carriage (see FIG. 3B). The cam surface of the lift cam 117 comes into contact with the upper surface of the L-shaped foot portion of the lift cam support member 150. All of the lift cam support members 150 are fixedly coupled to the rear structure 115 by screwing screws 153 at arbitrary positions in the height direction. When the carriage is assembled, the screw 153 is loosened and the height position is finely adjusted, so that the level of the print head 104 with respect to the platen 107 (the horizontal in the horizontal direction in FIG. 3B) is determined with high accuracy. Further, the front structure 114 is rotatable with respect to the rear structure 115 about the lift shaft 116, and the rotation is restricted by a rotation restricting member 151 coupled to the rear structure 115. Similar to the lift cam support member 150 described above, the rotation restricting member 151 is also fixedly coupled to the rear structure 115 by screwing a screw 152 at an arbitrary position in the front-rear direction. When the carriage is assembled, the screws 152 are loosened and the front and rear positions are finely adjusted, so that the level of the print head 104 with respect to the platen 107 (the level in the horizontal direction in FIG. 2B) is determined with high accuracy.

  In both the first form and the second form, when the carriage 105 is moved to the right end (home position shown in FIG. 3) of the apparatus, the lift coupling 118 is provided on the drive side coupling 119 provided on the side frame 119 of the printing apparatus. 120 is connected. The drive side coupling 120 is connected to a lift motor 121. When the lift motor 121 rotates in the CW direction (clockwise direction), the lift coupling 118 and the lift shaft 116 connected thereto rotate, and two lift cams 117 are connected. Rotate together. When the carriage 105 leaves the home position, the coupling is also released.

  Each of the two lift cams 117 has a smooth arc shape whose outer periphery is eccentric with respect to the rotation axis of the lift shaft 116, and these two have the same shape and the same dimensions. In the first embodiment, the cam support surface provided on the rear structure 115 is supported by contacting the outer periphery of the lift cam 117. In the second embodiment, the lift cam support member 150 contacts the outer periphery of the lift cam 117, and the height of the lift shaft 116 is determined via the lift cam support member 150.

  When the lift cam 117 is rotated, the height of the lift shaft 116 changes according to the change of the cam phase. That is, according to the eccentric amount of the lift cam 117, the cam support surface and the lift shaft 116 approach or separate from each other, and the relative height of the front structure 114 with respect to the rear structure 115 changes while supporting the horizontal. Yes. The shape of the lift cam 117 is such that the amount of eccentricity increases as the cam is rotated in the CW direction (clockwise direction) in the region where the print gap is changed (lift use section).

  This will be described with reference to FIG. FIG. 4A shows the shape of the lift cam 117. The direction of rotation of the cam by the motor is one direction of the CW direction (clockwise direction) and is not rotated in the reverse direction. FIG. 4B is a graph showing the relationship (lift cam diagram) between the cam rotation angle (cam phase) and the lift amount. The lift is set by fixing the cam somewhere in the lift use section with a rotation angle of 10 ° to 230 °. In the lift use section, the lift amount increases linearly as the cam rotation angle increases. For this reason, if the angle of the lift cam 117 is finely controlled, stopped at an arbitrary angle in the lift use section, and maintained at that angle, the print gap can be set to an arbitrary distance in a stepless manner or in multiple steps.

  Even if the lift cam 117 is stationary at a predetermined cam phase, if the force or vibration to rotate the lift cam 117 from the outside is applied, the lift cam 117 rotates without being maintained, that is, the set print gap changes. May end up. In order to prevent this, a one-way clutch 148 is attached to the lift shaft 116, and the lift shaft 116 rotates only in one direction (CW direction) and does not rotate in the reverse direction (CCW direction). . With this reverse rotation prevention structure, when the lift cam 117 is stationary at a certain phase, the eccentric amount of the lift cam 117 increases in the CW direction. If there is no strong driving force by a motor or the like, it cannot be rotated. At the same time, the one-way clutch cannot rotate in the CCW direction.

  As described above, the moving mechanism for changing the print gap is provided with the one-way clutch 148 in the transmission portion between the lift motor 121 and the lift cam 117. By the action of the one-way clutch 148, the lift cam 117 once stopped is prevented from rotating freely due to its own weight, vibration, etc., and the set print gap is maintained accurately.

  Next, a method for controlling the rotation of the lift cam 117 by the lift motor 121 will be described. In both the first form of FIG. 3A and the second form of FIG. 3B, a flag 134 for detecting the rotating cam phase is attached to the lift cam 117, and as the lift cam 117 rotates. The flag 134 also rotates. A sensor 135 made of a photo interrupter is attached to the rear structure 115 of the carriage 105. The timing at which the flag 134 shields the optical axis of the sensor 135 with the rotation of the lift cam 117 (ON) or the timing at which the flag 134 changes from light shielding to transmission (OFF) is set as the phase origin (starting point) of the lift cam 117. The lift motor 121 is provided with a rotary encoder, and can detect a rotation angle with high resolution. A controller to be described later controls the motor rotation with high accuracy based on the detection of the rotary encoder, with the timing at which the signal of the sensor 135 changes as the phase origin. By such control, the print gap can be adjusted with high accuracy at an arbitrary distance in a stepless manner or in multiple steps.

  FIG. 5 is an overall block diagram of the control system of the printing apparatus. In general, it is divided into a main body controller 131 and a carriage controller 132, which share the control. The main body controller 131 is a main controller that performs various controls of the entire printing apparatus. On the electric circuit board, a CPU 124, a storage unit (main body ROM 125, RAM 126), a head drive circuit 127, a motor drive circuit 128, and a main body connection port 149 are mounted. The main body ROM 125 (first storage unit) is a rewritable nonvolatile memory, specifically, a semiconductor memory such as EPROM, EEPROM, flash memory, MRAM, ReRAM, and FeRAM. The main body connection port 149 is an interface with a host computer connected to the power supply and printing apparatus. The contents of the main body ROM 125 can be rewritten by the host computer. The head drive circuit 127 controls ink ejection of individual recording elements of the print head 104. The carriage drive 110 and the lift motor 121 are driven by the motor drive circuit 128.

  The carriage controller 132 includes a carriage ROM 129 for storing individual carriage information, a carriage connection port 144, and the like on the electric circuit board, and also performs signal transmission and signal conversion between the print head and the main body controller. The carriage controller 132 is also connected to a head ROM 123 that is built in the print head 104 and stores head individual information, and a sensor ROM 130 that is built in a multi-sensor mounted on the carriage and stores sensor individual information.

  The carriage ROM 129, the head ROM 123, and the sensor ROM 130 (second storage unit) are rewritable nonvolatile memories like the main body ROM 125 (first storage unit). Specifically, the nonvolatile memory is a semiconductor memory such as EPROM, EEPROM, flash memory, MRAM, ReRAM, and FeRAM. It is possible to rewrite the contents of the carriage ROM 129, the head ROM 123, and the sensor ROM 130 by connecting to the host computer via the carriage connection port 144. The contents of the carriage ROM 129, the head ROM 123, and the sensor ROM 130 can be read and rewritten from the main body controller 131 side.

  The carriage ROM 129, the head ROM 123, and the sensor ROM 130 store unique unique ID information that is different for each unit for identifying the individual unit on which the ROM is mounted. Further, profile data (data table and mathematical expression) unique to the unit is stored. The main body ROM 125 also stores three pieces of ID information for the currently mounted carriage, multi-sensor, and print head. The unique ID information is symbol data including numbers and character strings.

  The contents (ID information, profile unique to the unit) stored in the main body ROM 125 may be stored in a storage unit of a host computer (external PC) connected to the printing apparatus.

<Method of canceling device-specific tolerances and error variations>
In the printing apparatus according to the above-described embodiment, one of the hardware features is an apparatus configuration that can arbitrarily set the distance of the print gap between the print head and the platen steplessly. In such a configuration, the objective is to reduce the influence of component tolerances and assembly error variations that differ from device to device, and to bring the print gap as close as possible regardless of the device. A technical concept for realizing this goal and canceling tolerances and error variations inherent in the apparatus will be described.

  The basic idea is that a correlation between the driving amount of the moving mechanism (lift motor 121) and the distance of the print gap, which is unique to the apparatus, is obtained in advance and the correlation data is stored in the storage unit. When the apparatus is actually used, the motor drive amount corresponding to the desired print gap distance is obtained by referring to the correlation data. That is, information unique to the apparatus is acquired for each apparatus in advance, and tolerances and error variations inherent in the apparatus are canceled using the information, and the target print gap is as close as possible regardless of the apparatus.

  One method for acquiring information specific to the device in advance is to acquire specific information for each individual unit using a dedicated measurement tool before final assembly of the printing device at the manufacturing factory (printer assembly site). is there. Here, a method of measuring unique information of the unit of the carriage 105 before final assembly will be described.

  FIG. 6A shows a state in which the carriage 105 in a unit state before being incorporated in the printing apparatus is mounted on the dedicated measurement tool 136 in the first embodiment shown in FIGS. 2A and 3A. FIG. FIG. 6B is a diagram showing a measurement state in the second form shown in FIGS. 2B and 3B. The measurement tool 136 has a support mechanism equivalent to a mechanism for supporting a carriage in an actual printing apparatus. Hereinafter, a dummy member corresponding to a member in an actual printing apparatus is referred to as “dummy XXX”.

  A dummy guide rail 138 and a dummy guide rail 139 are provided for the frame 137 that forms the skeleton of the measurement tool 136. These support the carriage 105 to be measured placed on the measurement tool 136 with the same positional relationship as the guide rail 112 and the guide rail 113 of the actual printing apparatus. The carriage 105 does not move in the main scanning direction on the measurement tool 136, and the dummy guide rail 138 and the dummy guide rail 139 are shorter than the guide rail 112 and the guide rail 113.

  At a position facing the supported carriage 105, a dummy platen 140 is provided at a position corresponding to the platen 107 in the actual printing apparatus. A dummy patch 141 (reference member for measurement) is provided at a position on the dummy platen 140 facing the multi-sensor 122 to measure distance and color. The dimensions and relative positional relationships of the dummy guide rail 138, the dummy guide rail 139, the dummy platen, and the dummy patch 141 are created to be equal to the design of the corresponding member in the actual printing apparatus.

  Further, the frame 137 is provided with a dummy motor 143 and a dummy coupling 142 connected thereto. Similar to the operation in the printing apparatus main body, the lift coupling 118 of the carriage 105 mounted on the measurement tool 136 is configured to be connected to the dummy coupling 142 and rotated.

  The measurement tool 136 has a tool controller 147 (control unit), and the tool controller 147 performs drive control of the dummy motor 143. The tool controller 147 is connected to the carriage connection port 144 of the carriage controller 132 and can perform read / write access to the carriage ROM 129. The tool controller 147 can further obtain a detection signal of the sensor 135 via the carriage controller 132.

  When the carriage 105 to be measured is set on the measurement tool 136 at the manufacturing factory, the carriage 105 holds a dummy head 145 for measurement instead of the actual print head 104. The dummy head 145 has the same dimensions as the actual print head 104 and does not have an ink discharge nozzle (recording element), but instead includes a distance measuring sensor 146. The distance sensor 146 can be used to measure the distance (referred to as a “dummy gap”) from the height position corresponding to the nozzle surface of the print head 104 to the opposing dummy platen 140. In this example, the distance measuring sensor 146 is a laser distance meter that can measure the distance to the object with higher accuracy than the multi-sensor 122. The sensor is not limited to the laser distance meter, and may be a sensor that measures a distance by another optical method, a method using an ultrasonic wave, an electric field, or the like.

  A specific adjustment procedure using the measurement tool 136 will be described below. First, the dummy motor 143 is rotated by a command from the tool controller 147. The rotational force of the dummy motor 143 rotates the lift cam 117 included in the carriage 105 through the dummy coupling 142 to move the front structure 114 up and down with respect to the stationary rear structure 115. In this process, the signal change at the moment when the flag 134 blocks the optical axis of the sensor 135 is captured and defined as the cam phase origin (angle 0 °). Then, the measured value (distance: unit mm) of the distance measuring sensor 146 and the received light amount (received signal level: unit mV) of the multi-sensor 122 facing the dummy patch 141 at this origin are obtained as digital data. Memorize temporarily.

  Next, while rotating the lift cam 117 in one direction (CW direction) from the angle 0 °, each of the measured value of the distance measuring sensor 146 and the received light amount of the multisensor 122 at every predetermined angle (10 ° in this example). Is temporarily stored in association with the corresponding angle. By repeating this measurement, the distance of the dummy gap acquired by the distance measuring sensor 146 and the amount of light received by the multi-sensor 122 at every lift cam angle that is the cam phase of the lift cam 117 (in this example, from 10 ° to 230 ° in 10 ° increments) Can be obtained.

  FIG. 7 shows the correlation data in the form of a data table. The tool controller 147 transmits these data to the carriage controller 132 and stores it in the carriage ROM 129 in the form of a data table as shown in FIG.

  For the stored data table of FIG. 7, interpolation processing such as linear interpolation and spline interpolation is performed between the angles. The correlation shown in FIG. 8 is obtained by the interpolation process. FIG. 8A is a lift cam profile showing the relationship between the lift cam angle (10 ° to 230 °) and the print gap distance (mm). FIG. 8B is a sensor profile showing the relationship between the lift cam angle (10 ° to 230 °) and the multi-sensor light reception amount (mV). The carriage ROM 129 stores these relationships. When these profiles are stored as data, either the form of a data table or the form of a mathematical expression to be converted may be used. In this specification, the lift cam profile stored in the memory is referred to as data stored in the storage unit, both in the form of a data table and a mathematical expression.

  The lift cam profile in FIG. 8A is information unique to the measured unit of the carriage 105, and different lift cam profiles can be obtained by measuring other carriage units in the same manner. Further, the sensor profile in FIG. 8B is information unique to the multi-sensor mounted on the carriage 105. By the interpolation process, it is possible to set an arbitrary print gap (lift cam angle) steplessly within the print gap setting range.

  After the measurement is completed using the measurement tool 136 in this way, the unit of the carriage 105 is incorporated into an actual printing apparatus by an assembly operator at the factory. When the print head is moved up and down so as to obtain a predetermined print gap when the completed actual printing apparatus is used, the main body controller 131 performs the following control.

  The main body controller 131 refers to the data (data table (FIG. 7) or lift cam profile (FIG. 8A)) stored in the carriage ROM 129 to obtain the value of the lift cam angle corresponding to a predetermined print gap. To do.

  Then, the lift motor 121 is rotated until the angle is reached and then stopped. For example, when the print gap is 1.0 mm, the lift cam angle corresponding to the lift cam profile of FIG. 8A stored in the carriage ROM 129 is 30 °. Accordingly, the lift motor 121 is driven so that the lift cam angle becomes 30 °. Note that the sensor profile of FIG. 8B is used for another application described later.

  The relationship between the print gap and the lift cam angle is different for each carriage. If there are variations in component tolerances and assembly errors, the lift cam angle for setting the print gap to 1.0 mm is 29 ° or 31 °, and the required drive amount of the lift motor differs depending on the apparatus. According to the present embodiment, since the individual difference is canceled by changing the driving amount according to the individual difference, as a result, an accurate print gap of 1.0 mm can be set in any apparatus without variation.

  As described above, before the carriage 105 unit is incorporated in the printing apparatus, the lift cam profile is obtained by holding a dedicated measurement tool, stored in the carriage ROM 129, and this information is read to control the print gap. As a result, inherent part tolerances and assembly errors of the carriage can be canceled, and an arbitrary print gap can be accurately set in a stepless manner or in multiple steps without variation between devices. This effect is produced by acquiring unique information of each of a plurality of carriage units by using one measuring tool as a measuring device.

  Note that once the contents stored in the ROM 129 are read from the carriage, the contents may be copied to the main body ROM 125, and the main body controller 131 may read the contents of the main body ROM 125 in the subsequent processing.

<Error correction of platen height eigenvalue>
As shown in FIG. 9, when the surface of the platen 107 has waviness, the height of the platen surface fluctuates depending on the location along the carriage movement direction (main scanning direction) (FIG. 9 is exaggerated for easy understanding). And draw). Since the sheet follows the surface of the platen, the height of the sheet supported by the platen also varies. For this reason, the print gap is not strictly kept constant in the range in which the carriage 105 reciprocates. When the carriage position changes, the print gap also fluctuates slightly. A solution technique for minimizing this effect is described below.

  The basic idea of the solution method is to measure the print gap at multiple locations within a predetermined range where the carriage reciprocates and determine the average value of them, so that the calculated average value becomes the target value of the platen gap. The profile is to be modified. As a result, even if there is a variation in the distance between the print head 104 and the sheet in the carriage movement range, it is within a certain range centered on the print gap target value. Even if the platen (the sheet on the platen) undulates, the overall average matches the target print gap, and good image printing is possible.

  FIG. 10 is a flowchart showing a specific processing sequence. In step 1, the unit-specific lift cam profile is stored in the carriage ROM 129 using the measurement tool 136 in the above-described procedure. In step 2 (assembly work), the carriage 105 is assembled to the actual main body of the printing apparatus. Then, the dummy head 145 used in the measurement of the lift cam profile is held on the carriage 105. A distance measuring sensor 146 is built in the dummy head 145.

  In step 3, the lift cam 117 is rotated so as to obtain a corresponding lift cam angle (30 ° in the example of FIG. 7B) with reference to the lift cam profile in order to obtain a predetermined print gap (1 mm in this example).

  In step S4, the carriage 105 is moved in the main scanning direction while maintaining the lift cam angle (30 °). Then, the distance (print gap) to the surface of the platen 107 is sequentially measured using a distance measuring sensor 146 at a plurality of locations within a predetermined movement range corresponding to the image print area. In this example, the measurement is performed at three positions, but the measurement may be performed at more positions.

  In step S5, an average value of a plurality of values obtained by measurement at a plurality of locations is calculated, and this average value is set as an average print gap. For example, as shown in FIG. 9, if the print gaps measured at three locations are 1.05 mm, 1.15 mm, and 0.95 mm, the average print gap is 1.05 mm. That is, the carriage 105 and the printing apparatus incorporating the carriage 105 in this example have a print gap that is 0.05 mm wider on average than the print gap of 1.0 mm in the profile obtained by using the measurement tool 136 in advance. Will be. Even if the target print gap is a distance different from 1 mm, an error of 0.05 mm is similarly applied.

  In step S6, a difference (+0.05 mm in this example) between the average print gap measured on the main body of the printing apparatus and the print gap measured on the measurement tool 136 is calculated. This is an eigenvalue depending on the printing apparatus itself. Hereinafter, this eigenvalue is referred to as “platen height eigenvalue”. The main factors causing variations in the platen height eigenvalue for each apparatus are component tolerances and assembly accuracy errors of main body parts such as the platen 107, the guide rail 112, and the guide rail 113. Then, the obtained platen height specific value is stored in the main body ROM 125 of the main body controller 131.

  When the platen height unique value is stored in the main body ROM 125, the manufacturing of the printing apparatus is completed. This is the process at the manufacturing plant. The completed printing device is packed and shipped. This previous process is a process at the user.

  In step S7, the printing apparatus is powered on by the user. In step S8, the main body controller 131 reads the lift cam profile stored in the carriage ROM 129 and the platen height unique value stored in the main body ROM 125. The actual print gap in this apparatus differs from the original design value by the platen height eigenvalue.

  In step S8, in order to cancel this, the lift cam profile is offset by the platen height eigenvalue, and a new “corrected lift cam profile” for deriving an appropriate lift cam angle is obtained.

  FIG. 11 is a graph showing the relationship between the original lift cam profile and the modified lift cam profile. The solid line in the graph represents the original lift cam profile stored in the carriage ROM 129. In this example, the target print gap is 1.0 mm and the lift cam angle is 30 ° obtained from the lift cam profile, but the platen height eigenvalue of 0.05 mm is added, and the actual print gap is 1.05 mm on average. . In other words, on average, the error is +0.05 mm with respect to the target original distance.

  Therefore, the lift cam profile is offset by 0.05 mm as a whole to newly obtain a corrected lift cam profile (dotted line in FIG. 11). The corrected lift cam profile is obtained by shifting the original lift cam profile up and down (in this example, up and down) in parallel in the graph by the platen height eigenvalue. Referring to this corrected lift cam profile, the lift cam angle corresponding to the target print gap of 1 mm is 23 °.

  The correction lift cam profile stores correction profile data in the main body ROM 125 and refers to this when using the apparatus. Alternatively, the correction profile data may not be stored, and the offset value of the platen height eigenvalue may be added every time the lift cam profile stored originally is referred to.

  Thus, the platen height eigenvalue, that is, the average value of the platen gap error in a predetermined range in the main scanning direction is offset to cancel. Based on the new correlation (corrected lift cam profile) between the obtained print gap and lift cam angle, actual cam drive is performed.

  In step S9, the lift cam 117 is rotated with reference to the corrected lift cam profile. Even if the print gap varies depending on the location in the range in which the carriage moves in image printing, the average distance is almost the same as the target print gap.

  Instead of using the corrected lift cam profile, the target print gap may be offset by 0.05 mm by an error of 0.95 mm, and the lift cam profile may be referred to based on the corrected target value. Even in this manner, the lift cam angle can be 23 °.

  As described above, according to the present exemplary embodiment, information specific to a unit incorporated in a printing apparatus is acquired, and the print gap is controlled so as to cancel individual differences between apparatuses. However, after that, a new error may occur due to various factors, and the accuracy of the print gap may decrease. The following are some cases and how to update the profile to improve accuracy.

<Case 1>
The first case in which the accuracy of the print gap is reduced is a case in which a position shift occurs in the mounting of components due to a strong impact in the transportation of the product after the product is shipped from the factory. To cope with this problem, initial calibration is performed when the apparatus is first turned on after unpacking after factory shipment.

  As described above, when measuring with the measurement tool 136 at the manufacturing factory, the multi-sensor light receiving amount is obtained for each lift cam angle with the multi-sensor 122 facing the dummy patch 141 and stored in the carriage ROM 129. .

  The dummy patch 141 on the dummy platen 140 of the measurement tool 136 has the same height, shape, and color as the platen patch 133 on the platen 107 of the actual printing apparatus. Therefore, if the platen patch 133 is measured again under the same conditions by the same multi-sensor 122, the same multi-sensor light reception amount as that stored in the carriage ROM 129 should be obtained. However, if the mounting of the component is displaced due to a strong impact before unpacking, a difference occurs in the amount of light received by the multisensor. It is the initial calibration that corrects this.

  FIG. 12 is a flowchart showing the initial calibration processing sequence. In step S11, the power of the printing apparatus main body is turned on. This is the first power-on after unpacking the product.

  In step S 12, the carriage is moved to a predetermined position, and the distance to the platen patch 133 is measured by the multisensor 122. The measured value is obtained as the amount of light received by the sensor (digitized numerical value).

  In step S13, the measurement value (sensor light reception amount) data of the dummy patch 141 stored in the carriage ROM 129 is read.

  In step S14, it is determined whether the measurement value obtained by the measurement in step S12 matches the data read in step S13. If they do not match, it is determined that the position of the component has shifted before unpacking, and the process proceeds to step S15. If they match, the sequence is terminated (END) without performing initial calibration.

  In step S15, the data (multi-sensor light reception amount) stored in the carriage ROM 129 is rewritten to the new measurement value obtained by measurement in step S12, and the content is updated.

  In step S16, the lift cam profile is updated. Specifically, a difference value between the measurement value obtained by the measurement in step S12 and the data read in step S13 is obtained. Then, the difference value is converted into a distance change value in the platen gap. With reference to the data table in FIG. 7 or the relative relationship in FIGS. 8A and 8B, the difference in the amount of received light can be converted into a change value of the print gap distance.

  Then, the platen height eigenvalue is updated with a value obtained by offsetting (adding or subtracting) the print gap distance change value from the platen height eigenvalue stored in the main body ROM 125. That is, the offset value to be corrected by the platen height eigenvalue platen swell is further rewritten to a value that is realistic.

  The graph of FIG. 13 shows the modified lift cam profiles before and after updating. The solid line is the original lift cam profile, the thick dotted line is the modified lift cam profile before update, and the thin dotted line is the updated corrected lift cam profile. The corrected lift cam profile after the update is obtained by shifting the corrected lift cam profile before the update up and down (down in this example) in the graph by the amount of distance change due to the component deviation during transportation.

  In this way, the platen height eigenvalue is further updated in accordance with the actual situation to obtain a new correlation (updated lift cam profile) between the print gap and the lift cam angle, and the actual cam drive is based on this. Do.

<Case 2>
The second case in which the accuracy of the print gap decreases is a case in which the error increases due to wear of parts or aging deterioration. In order to deal with this problem, periodic calibration is performed to periodically measure and update the profile.

  When the printer is used for a long time, the cumulative rotation of the lift cam 117 increases and the cam contact surface gradually wears. Further, as the cumulative number of reciprocations / movement distance of the carriage 105 increases, the guide rail 112, the guide rail 113, and the portion of the carriage that comes into contact therewith gradually wear. As the wear progresses, the distance of the print gap also changes gradually, and the accuracy with respect to the original distance decreases. Therefore, a calibration operation for updating the lift cam profile is performed so that information on the amount of change is acquired and does not exceed the allowable value.

  The concept before and after the update will be described using the graph of FIG. In FIG. 11, the dotted line is the lift cam profile before update, and the solid line is the updated corrected lift cam profile. The corrected lift cam profile is obtained by shifting the original lift cam profile up and down (up in this example) in the graph by the amount of change in distance due to component wear (in this example, 0.05 mm). Thereby, the accuracy of the print gap can be maintained over a long period of time.

  The calibration execution timing is determined by using the accumulated rotation amount of the lift cam 117, the number of scans / distance of the carriage, and the like as parameters. These parameters increase as the device is used. If any parameter exceeds a threshold value, calibration is executed. The threshold suitable for each parameter is determined so that the correlation between the parameter and the amount of variation in the print gap is obtained by an endurance experiment of the apparatus, and the amount of variation in the print gap is within a range that does not impair the print quality.

  FIG. 14 is a flowchart showing a calibration procedure corresponding to component wear. In step S21, the power of the printing apparatus main body is turned on. Here, the power is turned on every time the apparatus is started up.

  In step S22, the cumulative parameters related to the lift cam and carriage described above are read. In this example, two are parameters, that is, the cumulative amount of rotation of the lift cam, and the cumulative number of reciprocations or movement distance of the carriage.

  In step S23, it is determined whether each accumulated parameter exceeds a threshold value. If at least one parameter exceeds the threshold, the process proceeds to the next step S24. If neither parameter exceeds the threshold value, the sequence is terminated (END).

  In step S24, the carriage is moved to a predetermined position, and the distance to the platen patch 133 is measured by the multisensor 122. The measured value is obtained as the amount of light received by the sensor (digitized numerical value).

  In step S25, the lift cam profile is updated using the measurement value in step S24. Specifically, the difference between the previous multi-sensor measurement value already stored in the main body ROM and the current measurement value in step S24 is obtained and replaced with the change value of the print gap distance. This is converted into a distance change value with reference to the data table of FIG. 7 or the relative relationship of FIG. 8A and FIG. Then, the platen height unique value stored in the main body is offset (added or subtracted) by the change value of the print gap distance to correct the lift cam profile. The converted change value and the corrected lift cam profile are stored in the main body ROM 125 and updated.

  In step S26, the accumulated parameters regarding the replaced parts / units are reset. The parameters that are reset as the device is used are counted up. Thus, the sequence is finished.

<Case 3>
A third case in which the accuracy of the print gap decreases is a case where a new error is generated when a predetermined unit such as a carriage unit, multi-sensor, or print head is replaced during regular maintenance or failure repair. Since these units have different component tolerances and assembly errors from unit to unit, the print gap may deviate from the original distance after replacement.

  In order to solve this problem, each unit stores its own ID and unique information, and after replacement, the profile corresponding to the new unit is read and updated. In this example, the predetermined units are the carriage, the multi-sensor, and the print head. However, the predetermined unit is not limited to this, and may be another unit that affects the print gap.

  FIG. 15 is a flowchart showing a profile update sequence when a unit is replaced. In step S31, the printing apparatus main body is turned on. Here, the power is turned on every time the apparatus is started up.

  In step 32, the main body controller 131 reads ID information for identifying the unit from each of the ROMs (carriage ROM 129, sensor ROM 130, head ROM 123) built in the predetermined unit.

  In step S <b> 33, the main body controller 131 reads from the main body ROM 125 three pieces of ID information of the currently mounted carriage, multi-sensor, and print head.

  In step S34, it is determined for each of the three units whether the ID information read in step S33 matches the ID information read in step S34. For units whose IDs do not match, it is assumed that the units have been replaced during power-off, and the process proceeds to step S5. If the IDs do not match, the unit is not exchanged during power-off, and the subsequent steps are skipped and the sequence is ended (END). This determination and branching in step S34 are performed individually for each of the three units.

  In step S35, a profile or other information stored in advance is read from the ROM (any one of the carriage ROM 129, sensor ROM 130, and head ROM 123) of the replaced unit.

  The profile of the carriage ROM 129 is a lift cam profile showing the relationship between the lift cam angle and the print gap distance shown in FIG. The profile of the sensor ROM 130 is a sensor profile showing the relationship between the lift cam angle and the multi-sensor light receiving amount shown in FIG. The profile of the head ROM 123 is information regarding the height and inclination of the nozzle surface (recording element) in the print gap direction as head-specific information that the print head has. This is used as an offset value for further correction of the platen height eigenvalue as in the case 1 described above. Further, the profile of the head ROM 123 may be information relating to the position of the ejection nozzle with reference to the positioning portion (holder) of the carriage 105 that holds the print head, as head-specific information that the print head has.

  In step S36, the information read in step 35 is stored in the main body ROM 125, and the profile stored so far is updated to a new profile. In the lift cam drive control, if necessary information is read from the ROM in the individual unit each time, the main body ROM 125 may not store the profile information.

  In step S37, the ID information read in step S32 is stored in the main body ROM 125, and the ID information stored so far is updated to new ID information. Then, the sequence ends.

  As described above, prior to using the apparatus (printing operation), it is confirmed whether the unit has been replaced while the power is turned off by comparing the unique IDs. And about the unit exchanged during the power-off, unique information is read from the unit, and the profile applied to actual cam drive is updated. Therefore, even if the unit is replaced during maintenance or failure repair, the print gap can be maintained with high accuracy even after the replacement, and as a result, high-quality image printing is performed.

  In the above description, a unique unique ID (a symbol by a number or a character string) for identifying each unit is given. However, the profile itself can be regarded as unique information having a different numerical value for each unit. Therefore, in the previous steps S32 to S34, the profile itself may be used as the ID information.

  Note that the error correction of the platen height eigenvalue described above and Case 1 to Case 3 are processing sequences that are automatically executed after the power is turned on, but in response to an instruction from the user at any timing during use of the apparatus. The processing sequence may be executed based on this.

104 Print head 105 Carriage 106 Print unit 117 Lift cam 122 Multi-sensor 123 Head ROM
125 Main body ROM
129 Carriage ROM
139 Sensor ROM
136 Measuring tool 148 One-way clutch

Claims (19)

A printhead;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A printing apparatus comprising:
A storage unit storing correlation data between the driving amount of the moving mechanism and the distance, which is unique to the device,
A control unit that refers to the correlation data stored in the storage unit, obtains the driving amount corresponding to the target value of the distance, and drives the moving mechanism;
A printing apparatus comprising: A carriage that moves with the print head mounted thereon;
The storage unit stores in advance an average value of the distance in a predetermined range in which the carriage moves, which is unique to the apparatus,
The printing apparatus according to claim 1, wherein the control unit obtains the driving amount corresponding to the target value of the distance with reference to the correlation data and the average value. The moving mechanism includes a motor, a cam, and a transmission portion between the motor and the cam,
The printing apparatus according to claim 1, wherein the transmission unit is provided with a one-way clutch, and the stationary cam is prevented from rotating by the action of the one-way clutch.   The printing apparatus according to claim 3, wherein two cams are provided on both sides of the carriage in the moving mechanism, and the two cams rotate together.   The printing apparatus according to claim 1, wherein the correlation data unique to the apparatus is obtained by measurement using a measurement tool when the apparatus is assembled. A printhead;
A carriage that moves by mounting the print head;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A printing apparatus comprising:
A first storage unit provided in a main body of the printing apparatus or a host computer of the printing apparatus, in which correlation data between the driving amount of the moving mechanism and the distance specific to the apparatus is stored in advance;
A second storage unit provided in the print head, in which unique information about the print head is stored in advance;
Referring to the data stored in the first storage unit and the data stored in the second storage unit, the driving amount corresponding to the target value of the distance is obtained to drive the moving mechanism A control unit,
A printing apparatus comprising:   In the second storage section, as the unique information, information on the height or inclination of the recording element possessed by the print head, or information on the distance from the positioning section of the carriage holding the print head to the recording element The printing apparatus according to claim 6, wherein the printing apparatus is stored in advance. A printhead;
A carriage that moves by mounting the print head;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A sensor provided on the carriage and capable of measuring a distance between the print head and the platen;
A printing apparatus comprising:
A storage unit storing correlation data between the driving amount of the moving mechanism and the distance, which is unique to the device,
A control unit that refers to the correlation data stored in the storage unit, obtains the driving amount corresponding to the target value of the distance, and drives the moving mechanism;
Have
The printing apparatus, wherein the control unit is capable of updating the correlation data stored in the storage unit based on a result of measurement using the sensor.   When the cumulative amount of driving of at least one of the moving mechanism and the carriage reaches a threshold, the control unit performs measurement using the sensor and updates the correlation data stored in the storage unit. The printing apparatus according to claim 8, wherein the printing apparatus is characterized. A printhead;
A carriage that moves by mounting the print head;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A printing device comprising:
A first storage unit provided in a main body of the printing apparatus or a host computer of the printing apparatus, in which an average value of the distance in a predetermined range in which the carriage moves is stored in advance;
A second storage unit provided in the carriage, in which unique information of the carriage is stored in advance;
Referring to the data stored in the first storage unit and the data stored in the second storage unit, a driving amount corresponding to the target value of the distance is obtained, and the moving mechanism is driven. A control unit;
A printing apparatus comprising: A printhead;
A carriage that moves by mounting the print head;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A sensor provided on the carriage and capable of measuring a distance between the print head and the platen;
A printing apparatus comprising:
A first storage unit provided in a main body of the printing apparatus or a host computer of the printing apparatus, in which correlation data between the driving amount of the moving mechanism and the distance specific to the apparatus is stored in advance;
A second storage unit provided in the sensor, in which unique information about the sensor is stored in advance;
Referring to the data stored in the first storage unit and the data stored in the second storage unit, the driving amount corresponding to the target value of the distance is obtained to drive the moving mechanism A control unit,
A printing apparatus comprising: A printhead;
A carriage that moves by mounting the print head;
A platen provided facing the print head;
A moving mechanism for changing a distance between the print head and the platen;
A sensor provided on the carriage and capable of measuring a distance between the print head and the platen;
A printing apparatus comprising:
A storage unit of at least one unit among the carriage, the print head, and the sensor stores a first unique ID for identifying the unit,
In the main body of the printing apparatus or the host computer of the printing apparatus, the first unique ID read from the at least one unit incorporated in the apparatus is stored as a second unique ID,
Prior to a printing operation, it is determined whether the first unique ID and the second unique ID match, and if they do not match, the second unique ID is updated.   The storage unit stores unique information about the unit together with the first unique ID. When the first unique ID and the second unique ID do not match, the storage unit stores the unique information. The printing apparatus according to claim 12, wherein the information is read and updated.   The printing apparatus according to claim 1, wherein the print head is an ink jet head. A measurement tool for holding a carriage on which a print head is mounted and measuring individual information of the carriage,
A dummy guide for supporting the carriage;
A dummy platen provided facing the carriage supported by the dummy guide;
A moving mechanism for changing a distance between the print head and the dummy platen;
A measurement tool that stores data unique to the carriage in a storage unit included in the carriage based on a distance measured by a sensor that measures a distance between the print head and the dummy platen. A dummy head for measurement having a shape imitating a print head and capable of being held by the carriage;
The measurement tool according to claim 15, wherein the dummy head does not have a recording element and includes a distance measuring sensor for measuring a distance to the dummy platen. A dummy head for measurement having a shape imitating a print head on which a carriage of a printing apparatus is held, which can be held on the carriage,
A dummy head for measurement, characterized by a built-in distance measuring sensor for measuring the distance to an object. A printing apparatus control method capable of arbitrarily changing a print gap between a print head and a sheet,
Information specific to the apparatus that affects the print gap is obtained using a measurement tool different from the printing apparatus,
A control method for a printing apparatus, wherein the print gap is controlled using the acquired information.   A printing apparatus having unique ID information for identifying the unit of at least one unit constituting the printing apparatus, and determining that the unit has been replaced by reading the unique ID prior to a printing operation. Control method.

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