JP2020023173A - Image forming device, conveyance control method and conveyance control program - Google Patents

Abstract

To provide an image forming device, in which a necessity for adjusting accuracy of conveying a material to be recorded is eliminated.SOLUTION: In the image forming device that reads out using a photographing device a colorimetry pattern comprising a plurality of colorimetry patches recorded in a material to be recorded and has a colorimetry function of measuring color on the basis of the read-out photographed image, a conveying part conveys the material to be recorded, and a printing part records marker patterns on the material to be recorded so that the marker patterns are made closer to a downstream than a colorimetry pattern at the first line and in plural numbers at sides of the colorimetry patterns and so that a distance between the marker patterns is equal to a predetermined distance and so that a downstream-side marker pattern positioned closer to a downstream than the colorimetry pattern in the first line is included. The control part controls, based on distances between the plurality of marker patterns and the colorimetry pattern in the conveying direction of the material to be recorded, conveyance of the conveying part so that the material to be recorded is conveyed until when the colorimetry pattern on the material to be recorded is positioned at a reading-out position by the photographing device, and controls reading-out of the colorimetry pattern on the conveyed material to be recorded.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an image forming apparatus, a conveyance control method, and a conveyance control program.

  2. Description of the Related Art There is known a printing apparatus including a color measurement device that prints a color measurement pattern by transporting a printing medium (a variety of media such as paper and PVC) in a transport direction to a downstream side and a return direction to an upstream side. (Eg, Patent Document 1: Japanese Patent No. 4978278). When performing a colorimetric process, the printing apparatus prints a colorimetric pattern on a print medium, and then conveys the print medium to a drying unit (heating, blowing, etc.) on the downstream side. Then, after drying, the printing medium is rewound upstream by the colorimeter to the head position of the colorimetric pattern, and colorimetry is sequentially performed.

  However, conventionally, when the print medium is conveyed, the conveyance performance varies depending on the winding state of the paper feed roller and the winding roller, and therefore, it is necessary to adjust the conveyance accuracy. The adjustment of the transport accuracy differs depending on the transport direction and the type of print medium, and is very complicated.

  SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus, a transport control method, and a transport control program that improve the transport accuracy of a print medium.

  In order to solve the above-described problems and achieve the object, the present invention is to read a colorimetric pattern including a plurality of colorimetric patches recorded on a recording material with an imaging device, and perform colorimetry based on the read captured image. An image forming apparatus having a colorimetric function of performing a colorimetric function, comprising: a transport unit that transports a recording material; a marker pattern on the recording material; a plurality of marker patterns on a side of the colorimetric pattern; and a distance between the marker patterns. A printing unit that records so as to have a predetermined distance, and includes a downstream marker pattern positioned downstream from the first line of the colorimetric pattern, and a plurality of markers in the transport direction of the recording material. Based on the distance between the pattern and the colorimetric pattern, the transport unit is controlled to transport the recording material until the colorimetric pattern on the recording material is located at the reading position by the imaging device. And a control unit for controlling the imaging device to read the colorimetric pattern of the recording material that is.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the conveyance precision of a printing medium can be improved.

FIG. 1 is a diagram illustrating an external configuration of an inkjet recording apparatus according to an embodiment. FIG. 2 is a plan view showing a scanning mechanism of a carriage provided in the inkjet recording apparatus. FIG. 3 is a block diagram illustrating a configuration of a drive control system of the inkjet recording apparatus 100. FIG. 4 is a cross-sectional view of the transport path during printing. FIG. 5 is a cross-sectional view of the transport path during winding. FIG. 6 is a diagram illustrating an example of an image printed on a print medium during color measurement. FIG. 7 is a diagram for explaining a transport error at the time of rewinding. FIG. 8 is a diagram illustrating a print example of a marker pattern for position adjustment in the inkjet recording apparatus according to the first embodiment. FIG. 9 is a diagram illustrating another example of printing of the marker pattern for position adjustment in the inkjet recording apparatus according to the first embodiment. FIG. 10 is a flowchart illustrating the flow of the transport control according to the first embodiment. FIG. 11 is a diagram illustrating a print example of a position adjustment marker pattern in the inkjet recording apparatus according to the second embodiment. FIG. 12 is a diagram illustrating an example of imaging of a marker pattern in the inkjet recording apparatus according to the second embodiment. FIG. 13 is a diagram illustrating an example of imaging at the time of color measurement in the inkjet recording apparatus according to the second embodiment. FIG. 14 is a flowchart illustrating a flow of conveyance control in the inkjet recording apparatus according to the second embodiment. FIG. 15 is a diagram illustrating a print example of a position adjustment marker pattern in the inkjet recording apparatus according to the third embodiment. FIG. 16 is a flowchart illustrating the flow of the transport control according to the third embodiment.

  Hereinafter, an inkjet recording apparatus according to an embodiment to which an image forming apparatus, a conveyance control method, and a conveyance control program are applied will be described.

(Configuration of inkjet recording apparatus)
FIG. 1 is a diagram illustrating an external configuration of an inkjet recording apparatus 100 according to an embodiment. FIG. 2 is a plan view showing a scanning mechanism of a carriage provided in the inkjet recording apparatus 100. As can be seen from FIGS. 1 and 2, the ink jet recording apparatus 100 has a carriage 5 movably held in a direction indicated by an arrow A (main scanning direction) by a guide rod 1 laid over both inner side plates. I have.

  The carriage 5 is connected to a timing belt 11 wrapped around a driving pulley 9 and a pressure pulley 10. When the timing belt 11 is driven by the main scanning motor 8 via the driving pulley 9, the carriage 5 reciprocates in the main scanning direction A. The tension is applied to the timing belt 11 by the pressure pulley 10, so that the carriage 5 can be driven without slack.

  The print medium M (an example of a recording material) is intermittently transported along the direction of arrow B (sub-scanning direction) below the reciprocating carriage 5. A predetermined image is formed on the print medium M by discharging ink droplets from the nozzles of the recording head 6 (6k, 6c, 6m, 6y) provided on the carriage 5 on the platen 16. Note that “k” means a key plate (or black), “c” means cyan, and “m” means magenta “y” means yellow. The printing medium M on which the image is formed is dried by the drying heater 17.

  In addition, the inkjet recording apparatus 100 includes a cartridge 2 for supplying ink to the recording head 6 and a maintenance mechanism 26 for performing maintenance of the recording head 6 provided on the carriage 5. An encoder sensor 13 is arranged in the carriage 5, and continuously reads the encoder sheet 14 stretched between the both side plates, thereby driving between the two side plates while detecting the position in the main scanning direction.

  The imaging control unit 20 has an imaging processing device provided on the carriage 5 and capable of capturing print data on a print medium, and is capable of detecting an image position and performing colorimetric processing from the captured image data. .

(Configuration of drive control mechanism)
FIG. 3 is a block diagram illustrating a configuration of a drive control system of the inkjet recording apparatus 100. As shown in FIG. 3, the inkjet recording apparatus 100 includes, as a drive control system, a control section 61, a transport section 62, a sub-scanning motor 63, a winding section 64, a winding section, together with the carriage 5 and the main scanning motor 8 described above. It has a motor 65, a paper feeding unit 66 and a paper feeding motor 67.

  The control unit 61 includes a CPU (central processing unit) 41, an FPGA (Field Programmable Gate Array) 42, and a motor driver 43. The control unit 61 performs CPU control, memory control, ink ejection control, sensor control, motor control, and the like.

  The carriage 5 driven by the main scanning motor 8 has a recording head 45, a main scanning encoder sensor 46, and a two-dimensional sensor 47 (two-dimensional image sensor: an example of an imaging device). The two-dimensional sensor 47 has a CPU 48 for a two-dimensional sensor and an imaging unit 49.

  The transport unit 62 driven by the sub-scanning motor 63 has a sub-scanning encoder sensor 50 and a transport roller 51. The winding unit 64 driven by the winding motor 65 has a winding encoder sensor 52 and a winding roller 53. The paper supply unit 66 driven by the paper supply motor 67 has the paper supply encoder sensor 54 and the paper supply roller 55. Note that the recording head 45, the control unit 61, the transport unit 62, and the winding unit 64 are examples of a printing unit.

(Conveyance operation of printing medium during printing)
FIG. 4 is a cross-sectional view of the transport path during printing. In FIG. 4, the print medium M is set on a paper feed roller 35, and is fixed to a take-up roller 34 via a paper feed guide 32, a transport roller 33, a platen 30, and a paper discharge guide 31 in this order. The take-up roller 34, the transport roller 33, and the paper feed roller 35 are driven to rotate by a take-up motor 65, a sub-scanning motor (transport motor) 63, and a paper feed motor 67, respectively. The print medium M is transported. At this time, the feeding roller 35 controls the speed of the feeding motor 67 so that the direction of the torque is opposite to the feeding direction so that the print medium M does not bend on the feeding path. .

  After the printing process is performed on the platen, the drying process of the ink is performed by the drying heater 17 of the discharge guide 31. Note that the drying process by the drying heater 17 is not always necessary, and after the measurement pattern is recorded, the drying process may be performed by leaving it for a predetermined time.

  Here, the roll diameter of the winding roller 34 and the paper feeding roller 35 varies according to the winding amount of the print medium M. The example of FIG. 4 shows a state where the diameter of the take-up roll is small and the diameter of the paper feed roll is large. In the conveyance in the sub-scanning direction during printing, the smaller the take-up roll diameter, the smaller the bite of the print medium M into the conveyance roller 33. Further, the larger the diameter of the paper feed roll, the smaller the bite of the print medium M into the transport roller 33. The greater the depth, the apparently the transport roller diameter becomes smaller, so that the transport amount becomes smaller, and conversely, the smaller the bite, the larger the transport roller diameter, the greater the transport amount. Becomes larger. At the time of printing, in order to keep the variation of the transport amount constant, the transport amount is maintained constant by adjusting the rotation amount of the transport roller 33 in accordance with the state of the roll diameter for winding and feeding.

  The diameter of the paper feed roll can be calculated from the rotation speed of the paper feed encoder sheet 35 e and the paper feed encoder sensor 54. The winding roll diameter can be calculated from the rotation speeds of the encoder sheet 34 e and the winding encoder sensor 52.

  In addition to the condition of the roll diameter, the intrusion of the print medium M into the transport roller 33 differs depending on the type of the print medium M, and it is necessary to perform the correction process for each print medium M. These correction processes are very complicated.

  When the transport roller 33 is a metal roller, a gripping force at the time of transport can be obtained by making the print medium M bite into the mountain of the roller, but the difference in the bite amount causes a disadvantage that a transport error occurs. . On the other hand, when a ceramic roller or a rubber roller is used as the transport roller 33, a transport error due to a difference in biting into the transport roller 33 does not occur. However, the print medium M may slip on the transport roller 33, resulting in a transport error.

(Conveyance operation of print medium during winding)
FIG. 5 is a cross-sectional view of the transport path during winding. At the time of winding, the rotation direction of the transport roller 33 is opposite to the direction of printing. The rotation direction of the feed roller and the take-up roller does not change, but the print medium M is transported in the sub-scanning direction C by adjusting the rotation speed. In the example of FIG. 5, the winding roll diameter is small and the paper feeding roll diameter is large.

  In the conveyance in the winding direction, the smaller the take-up roll diameter, the greater the bite of the print medium M into the conveyance roller 33, and the smaller the conveyance amount, the smaller the conveyance amount. Further, as the diameter of the paper feed roll increases, the depth of the printing medium M with respect to the transport roller 33 increases, so that the transport amount fluctuates in a direction in which the transport amount decreases (a characteristic opposite to that in the printing direction).

  In order to keep the transport speed constant, it is necessary to adjust the rotation amount of the transport roller 33 according to the type of the print medium M, the state of the take-up roller diameter and the state of the paper feed roller diameter, as in printing. However, these adjustments have many conditions and are very complicated. Further, transport accuracy is required at the time of printing, but less transport accuracy is required at the time of rewinding.

(Example of image printed on print medium during color measurement)
FIG. 6 is a diagram illustrating an example of an image printed on a print medium during color measurement. As shown in FIG. 5, the colorimetric pattern P is composed of m rows × n columns of patch groups P1-1 to Pm-n. Let D be the distance from the patch center of the first row to the patch center of the m-th row. The marker pattern X is a pattern for position adjustment, and is printed downstream of the patch at an interval of a unique distance L from the patch in the first row.

(Transport error during rewinding)
FIG. 7 is a diagram for explaining a transport error at the time of rewinding. In FIG. 7, the transport error ΔS is the target “transport amount−actual transport amount”, and the range of the transport error increases in proportion to the target transport amount. Further, the inclination of the range of the transport error varies depending on the type of the print medium M. The condition that the transport error ΔS is a value on the plus side is a condition that the actual rewind transport amount is insufficient with respect to the target rewind transport amount. Conversely, the condition for the transport error ΔS to be a negative value is that the actual unwinding transport amount is larger than the target rewind transport amount.

  Here, the maximum value ΔSmax on the plus side of the transport error ΔS is a transport amount margin at the time of rewind transport. Since the carry amount margin changes in accordance with the type of the print medium M, the CPU 41 of the control unit 61 calculates the carry amount margin in advance as a design value.

(Example of position adjustment marker pattern printing)
FIGS. 8 and 9 are diagrams illustrating an example of printing a position adjustment marker pattern in the inkjet recording apparatus 100 according to the first embodiment. In the case of the first embodiment, a plurality of marker patterns such as the marker patterns X1 to X5 and the colorimetric pattern P are printed on the print medium M.

  The marker patterns X1 to X5 are printed outside the range of the colorimetric pattern P in the main scanning direction. Further, the marker pattern of X3 at the center of the marker patterns X1 to X5 is arranged downstream from the center 21a of the colorimetric pattern P in the first row. The interval between the marker patterns X1 to X5 in the sub-scanning direction is equal, and the interval is equal to or less than the length of the imaging range 20a of the two-dimensional sensor 20 in the sub-scanning direction. Thereby, one or more marker patterns can be printed in the imaging range 20a of the two-dimensional sensor 20. After printing the colorimetric pattern P and the marker patterns X1 to X5, the drying heater 17 performs a drying process on the ink.

  Subsequently, with respect to the transport at the time of rewinding, the imaging range 20a of the two-dimensional sensor 20 is set to the downstream of the nearest position from the position of the colorimetric pattern P in consideration of the target transport amount S and the maximum transport error ΔSmax. The print medium M is transported in the “rewind direction C” by the amount including the transport error, aiming at the marker pattern X3. The reason for aiming at the downstream marker pattern X3 closest to the position of the colorimetric pattern P by rewinding is that if the marker pattern X3 can be detected, the print medium is transported in the downstream direction (print medium feed direction B during printing). This is because the carriage 5 can be moved to the center of the colorimetric pattern P in the first row with high accuracy and with the shortest number of transports.

  The marker patterns X1 and X2 are arranged downstream of the marker pattern X3, and the marker patterns X4 and X5 are arranged upstream of the marker pattern X3. This is to ensure a margin for the transport return control so that any one of the marker patterns X1 to X5 can be detected.

  After rewinding is completed, the main scanning position of the carriage 5 is adjusted, and the center position of the marker pattern (marker pattern X3 in this example), which is the center of the marker pattern group, is set within the imaging range 20a of the two-dimensional sensor 20. The carriage 5 is moved to enter. For example, a plurality of cross marks are arranged as the marker patterns X3 to X5. When an odd number of cross marks are arranged, the intersection of the center cross marks is set as the center position. In the case where an even number of cross marks are arranged, the middle point between the cross marks at both ends is set as the center position.

  After adjusting the main scanning position of the carriage 5 as described above, the print medium M is imaged by the two-dimensional sensor 20, and any one of the marker patterns X1 to X5 is detected. In the marker patterns X1 to X5, the number of “+” and the position in the main scanning direction are arranged differently, and any of the marker patterns X1 to X5 is recognized based on the difference. In the example of FIG. 9, since the marker pattern is detected on the right side of the center P1 of the imaging range 20a, it can be determined that the detected marker pattern is the marker pattern X2 or the marker pattern X4. Similarly, if it is on the left side of the imaging range 20a, it can be determined that it is the marker pattern X1, the marker pattern X3, and the marker pattern X5. The final identification of the marker patterns X1 to X5 is performed based on the position in the main scanning direction (the left and right position of the imaging range 20a) and the number of cross patterns.

  When any of the marker patterns X1 to X3 is detected, the distance from the center coordinates of the two-dimensional sensor 20 to the center coordinates of the first line of the colorimetric pattern is calculated, and the print medium is conveyed in the printing direction B (marker pattern). The distance to the center coordinate of the colorimetric pattern P in the first row is calculated according to the number of the first line.) Thereafter, the colorimetric patterns P are sequentially read, and colorimetry is performed for all patches.

  When any one of the marker patterns X4 to X5 is detected, a distance from the center coordinates of the corresponding marker pattern to the center coordinates of the downstream marker pattern X3 closest to the first line of the colorimetric patch is calculated. The print medium M is transported in the rewind direction C (the distance to the center coordinate of the marker pattern X3 is calculated according to the marker pattern number). Thereafter, the process follows the process of detecting the marker pattern X3 from the marker pattern X1.

  Once transport to the downstream marker pattern X3 closest to the first line of the colorimetric patch, the feed accuracy in the sub-scanning direction is higher when "the print medium M is transported in the print direction B" than when it is returned. It has become. Therefore, the center 21a of the first line of the colorimetric pattern P and the two-dimensional sensor 20 are moved once to the marker pattern downstream of the colorimetric pattern P by rewinding conveyance and sending the print medium M in the printing direction B. The position can be adjusted so that the position of the imaging range 20a is optimized.

  In the case of the marker pattern X1, the distance from the center coordinates of the marker pattern to the first line of the colorimetric patch is L1. In this example, since the marker pattern is arranged above the center of the imaging range 20a, the distance from the center of the imaging range 20a to the first line of the colorimetric patch is “L1 + Y × α”. By transporting the printing medium M in the printing direction B by the length calculated by the above calculation, the first line of the colorimetric patch can be included in the imaging range 20a of the two-dimensional sensor 20.

  FIG. 10 is a flowchart showing the flow of the transport control according to the first embodiment. Each process of the flowchart of FIG. 10 is executed by the CPU 41 of the control unit 61 shown in FIG. 3 based on the transport control program stored in the memory 68.

Step S21: Simultaneously with printing of the colorimetric pattern, printing of the marker patterns X1 to X5 is performed outside the colorimetric pattern range in the main scanning direction A. Then, the printing medium is conveyed and printed repeatedly until the printing is completed.
Step S22: The drying heater 17 performs an ink drying process.
Step S23: The print medium M is transported in the rewind direction by an amount including the transport error until the imaging range 20a of the two-dimensional sensor 20 is located downstream of the position of the colorimetric pattern P.
Step S24: The two-dimensional sensor 20 performs a marker pattern detection process.
Step S25: It is determined whether or not the marker pattern is located downstream from the center of the first line of the colorimetric patch in the sub-scanning direction.
Step S26: Since it is determined that the marker pattern is located downstream from the center in the sub-scanning direction of the first line of the colorimetric patch (Step S25: Yes), one line of the colorimetric patch is determined from the center coordinates of the imaging range 20a of the two-dimensional sensor 20. The distance to the center coordinates of the eye is calculated, and the print medium M is transported in the printing direction (the distance is calculated according to the number of the marker pattern).
Step S27: The colorimetric patterns are sequentially read, and the colorimetry for all the patches is performed.
Step S28: Since it is determined that the marker pattern is located upstream from the center in the sub-scanning direction of the first line of the colorimetric patch (Step S25: No), the first line of the colorimetric patch is determined from the center coordinates of the corresponding marker pattern. The distance to the center coordinate of the nearby downstream marker pattern (X3) is calculated, and the print medium is transported in the rewind direction (the distance is calculated according to the marker pattern number). Thereafter, the process returns to step S24.

(Effects of the First Embodiment)
As is clear from the above description, the ink jet recording apparatus 100 of the first embodiment prints the marker pattern X at a position downstream from the color measurement pattern by the distance L1 in the sub-scanning direction. Thus, the start position of the colorimetric pattern can be calculated from the detected position of the marker pattern, and the position of the imaging range 20a (colorimetric range) of the two-dimensional sensor 20 can be adjusted to the start position of the colorimetric pattern.

  Since the marker pattern is arranged on the side of the colorimetric pattern P, the print medium M used for positioning processing with the colorimetric pattern by rewinding can be minimized. Further, the number of marker patterns can be increased on the side without worrying about an increase in consumption of the printing medium M used for the positioning process, and a control margin can be secured to improve the conveyance accuracy of the printing medium M. . Further, since the control margin can be secured, the printing medium M can be rewound at high speed, and the processing can be speeded up.

  In addition, by arranging the marker patterns on the side of the colorimetric pattern P (outside the colorimetric pattern image range in the main scanning direction), many marker patterns that are long in the main scanning direction can be arranged, and a margin for return control of conveyance can be secured. . In addition, it is possible to minimize the amount of media consumed for adjustment while ensuring a control margin (the marker pattern can be arranged at a minimum downstream of the colorimetric pattern).

  Further, since the marker patterns are printed at regular intervals in the sub-scanning direction, it is possible to determine the number of the detected marker pattern counting from the main scanning position in the imaging range. Since the distance from the coordinates of the center point of the detected marker pattern to the coordinates of the colorimetric pattern is uniquely determined, it is possible to calculate between the positions of the colorimetric pattern.

  That is, the inkjet recording apparatus 100 according to the first embodiment can eliminate the need for transport accuracy of rewinding the print medium M, and can simplify the transport mechanism. Further, the amount of recording material used for pattern position detection can be minimized. Further, since the position can be detected by a small number of times of image pickup for position adjustment, the processing can be speeded up.

  Further, the ink jet recording apparatus 100 according to the first embodiment arranges the marker patterns X1 to X5 on the side of the colorimetric pattern P (outside the colorimetric pattern image range in the main scanning direction), so that the length is longer in the main scanning direction. A large number of marker patterns can be arranged, and a margin for return control of conveyance can be secured to improve the conveyance accuracy of the print medium M. In addition, it is possible to minimize the amount of media consumed for adjustment while ensuring a control margin (the marker pattern can be arranged at a minimum downstream of the colorimetric pattern).

(Second embodiment)
Next, an ink jet recording apparatus 100 according to a second embodiment will be described. In order to omit redundant description, only the differences from the above-described first embodiment will be described below.

(Example of position adjustment marker pattern printing)
FIG. 11 shows an example of printing a position adjustment marker pattern in the inkjet recording apparatus 100 of the second embodiment, and FIG. 12 shows an example of imaging of the marker pattern in the inkjet recording apparatus 100 of the second embodiment. FIG. 13 illustrates an example of imaging at the time of color measurement in the inkjet recording apparatus 100 according to the second embodiment. As described in the example of FIG. 6, the marker pattern X and the colorimetric pattern P are printed on the print medium M. After printing all the colorimetric patterns, the ink is dried. When the drying process is performed by the drying heater 17 of the discharge guide, the print medium M is transported to the discharge guide. When drying the colorimetric pattern by leaving it at the recording position for a predetermined time, it is not necessary to convey the colorimetric pattern in the printing direction after printing the colorimetric pattern on the last line.

  The ink jet recording apparatus 100 according to the second embodiment winds the print medium M on which the colorimetric pattern printing and the drying process have been completed, including the above-described transport amount margin, instead of performing the transport amount adjustment during the rewind transport. return. As the carry amount margin, the maximum carry error ΔSmax is calculated from the target rewind amount, and the carry-back is performed so that the marker pattern X including the ΔSmax is located upstream of the start position (downstream) of the imaging range 20a.

  After the rewinding is completed, the position of the carriage is adjusted, and the carriage is moved so that the main scanning position of the marker pattern X falls within the imaging range 20a of the two-dimensional sensor 20. After adjusting the main scanning position of the carriage, the print medium is imaged by the two-dimensional sensor 20, and the marker pattern X is detected.

  If the marker pattern cannot be detected, the print medium M is transported in the print direction B so that the upstream side is in the imaging range. The distance between the two-dimensional sensor 20 and the print medium M is based on the premise that the distance of the thickness of the print medium M is negligible. I have.

  After the printing medium M is transported in the printing direction B, the above-described imaging processing is performed again, and imaging and transporting of the printing medium are alternately performed until the marker pattern X is detected.

  When the marker pattern X is detected, as shown in FIG. 12, the number Y of pixels that are shifted in the transport direction of the print medium between the center position P1 of the imaging range 20a and the center position P2 of the marker pattern X is determined.

  Here, assuming that the print size of the marker pattern X is a (mm) and the number of pixels of the marker pattern X is A (pixel), the length α per pixel can be calculated as “α = a / A” ( The unit is mm). Since the distance between the two-dimensional sensor 20 and the print medium M is roughly known as described above, the length α per pixel is also known as an approximate value. May be omitted. As shown in FIG. 13 as an example of imaging at the time of colorimetry, the patch size of the colorimetric pattern is larger than the imaging range for the colorimetric processing, so that there is no effect on the colorimetric processing even if there is some transport error.

  From the value of the displacement pixel number Y and the value of the length α per pixel, the marker pattern X is deviated from the center of the imaging range 20a by “Y × α” (unit: mm).

  Here, when the marker pattern X is captured on the downstream side from the center of the imaging range 20a, the distance from the center of the imaging range 20a to the first line of the colorimetric patch is “LY × α”. Conversely, when an image is captured on the upstream side from the center of the imaging range 20a, the distance from the center of the imaging range to the patch in the first line of the colorimetric patch is “L + Y × α”. By transporting the printing medium M in the printing direction B by the length calculated by this calculation, the two-dimensional sensor 20 can capture the colorimetric patches on the first line.

(Transport control flow)
FIG. 14 is a flowchart illustrating a flow of the conveyance control in the inkjet recording apparatus 100 according to the second embodiment. The processing of each step in this flowchart is executed by the CPU 41 of the control unit 61 shown in FIG. 3 based on the transport control program stored in the memory 68.

Step S1: One marker pattern is printed.
Step S2: The print medium is transported in the printing direction.
Step S3: Print a colorimetric pattern. Until printing is completed, conveyance and printing of the print medium M are repeated.
Step S4: A drying process of the ink is performed by the drying heater 17 (or natural drying).
Step S5: The print medium M is transported in the rewind direction by an amount including a transport error margin until the imaging range 20a of the two-dimensional sensor 20 is on the downstream side of the position of the colorimetric pattern.
Step S6: An image is captured by the two-dimensional sensor 20, and a marker pattern detection process is performed.
Step S7: It is determined whether or not a marker pattern has been detected.
Step S8: Since the marker pattern is detected (Step S7: Yes), the coordinates of the center point of the marker pattern are detected.
Step S9: The distance from the central coordinates of the imaging range 20a of the two-dimensional sensor 20 to the central coordinates of the first line of the colorimetric patch is calculated, and the print medium M is transported in the print direction.
Step S10: The colorimetric patterns are sequentially read, the colorimetry for all the patches is performed, and the processing of the flowchart ends.
Step S11: Since no marker pattern is detected (Step S7: No), the print medium M is transported in the printing direction by an amount corresponding to the imaging range 20a, and the process returns to Step S6.

(Effect of Second Embodiment)
As is clear from the above description, the ink jet recording apparatus 100 of the second embodiment prints the marker pattern X at a position downstream from the color measurement pattern by a distance L along the sub-scanning direction. Thus, the start position of the colorimetric pattern can be calculated from the detected position of the marker pattern, and the position of the imaging range 20a (colorimetric range) of the two-dimensional sensor 20 can be adjusted to the start position of the colorimetric pattern.

  That is, the inkjet recording apparatus 100 according to the second embodiment can eliminate the need for the transport accuracy of rewinding the print medium M, and can simplify the transport mechanism. Further, the amount of recording material used for pattern position detection can be minimized. Further, since the position can be detected by a small number of times of imaging for position adjustment, the processing can be sped up.

(Third embodiment)
Next, an ink jet recording apparatus 100 according to a third embodiment will be described. In order to omit redundant description, only the differences from the above embodiments will be described below.

  FIG. 15 is a diagram illustrating a print example of a position adjustment marker pattern in the inkjet recording apparatus 100 according to the third embodiment. In the case of the third embodiment, for example, seven marker patterns X1 to X7 and a colorimetric pattern P are printed on the print medium M.

  The marker patterns X1 to X7 are printed outside the colorimetric pattern range in the main scanning direction. Also, of the marker patterns X1 to X7, only the marker pattern X1 is arranged downstream of the center 21a of the first line of the colorimetric pattern. The marker patterns X1 to X7 are equally spaced, and the distance is equal to or smaller than the main scanning direction distance of the imaging range 20a of the two-dimensional sensor 20. This makes it possible to print one or more marker patterns within the imaging range 20a of the two-dimensional sensor 20. After printing all the colorimetric patterns P and the marker patterns X1 to X7, the drying heater 17 performs a drying process on the ink.

  Subsequently, as for the transport at the time of rewinding, the range of the imaging device is changed to the marker pattern X1 to T4 in consideration of the target transport amount S and the maximum transport error ΔSmax, as in the first embodiment. The print medium M is transported in the “rewinding direction C” by the amount including the transport error, aiming at the marker pattern X4 located at the center of X7.

  The reason for aiming the marker pattern X4 at the center of the marker patterns X1 to X7 by rewinding is that if the marker pattern X4 can be detected, the marker pattern X1, marker pattern 2 and marker pattern 3, marker pattern X5 and marker pattern X5 are respectively set to the upper limit of X4. This is because a control margin for detecting three patterns can be secured in the vertical direction by the pattern X6 and the marker pattern X7. In this case, since the rewinding control can be handled by coarse control (rough control is sufficient), the print medium M can be transported at a higher speed than the transport speed in the normal pattern position detection return control. Therefore, when the rewind distance is long, the rewind processing can be performed in a short time.

  As the rewinding speed, two rewinding speeds of a conveying rewinding speed V1 toward X4 and a conveying rewinding speed V2 for the marker pattern “X2-7” → X1 ”are set. The relationship between the rewind speeds V1 and V2 is "V1> V2". This makes it possible to shorten the rewinding time.

  After rewinding is completed, the main scanning position of the carriage 5 is adjusted so that the center position of the center of the marker pattern group (the marker pattern X4 in this example) is within the imaging range 20a of the two-dimensional sensor 20. Move. Cross marks are arranged as the marker patterns X2, X3, X5, X6 and X7. When an odd number of cross marks are arranged, the intersection point of the center cross mark is set as the center. When an even number of cross marks are arranged, the center is set at the center point between the cross marks at both ends.

  After adjusting the main scanning position of the carriage 5, the print medium M is imaged by the two-dimensional sensor 20, and any one of the marker patterns X1 to X7 is detected. The marker patterns X1 to X7 are arranged so that the number of “+” and the position in the main scanning direction are different, and the difference is used to determine the difference between the marker pattern X1 and the marker pattern X7 as described in the second embodiment. Recognize either.

  When any of the marker patterns X2 to X7 is detected, the center coordinates of the detected marker pattern and the distance between the center coordinates of the detected marker pattern and the center coordinates of the marker pattern X1 arranged downstream from the center 21a of the first line of the colorimetric pattern. Is calculated, and the print medium is transported in the rewind direction C (distances are calculated according to the marker pattern numbers).

  The sheet is once conveyed to the marker pattern X1 (disposed downstream of the center 21a of the first line of the colorimetric pattern) for the following reason. The feeding accuracy in the sub-scanning direction is higher when "the print medium is conveyed in the printing direction B" than when the return conveyance is performed. For this reason, the print medium moves once by rewinding and transporting to the marker pattern downstream of the colorimetric pattern P, and sends the print medium in the print direction B. Thereby, the position can be adjusted so that the center 21a of the first line of the colorimetric pattern and the position of the imaging range 20a of the two-dimensional sensor 20 are optimized.

  When the marker pattern X1 is detected, the distance from the center coordinates of the marker pattern X1 to the first line of the colorimetric patch is L1. As described in the second embodiment, the distance from the center of the imaging range to the first line of the colorimetric patch is calculated. By transporting the print medium M by the calculated distance in the printing direction B, the first line of the colorimetric patch can be included in the imaging range 20a of the two-dimensional sensor 20. Thereafter, the colorimetric patterns are sequentially read, and colorimetry is performed for all patches.

  FIG. 16 is a flowchart showing the flow of the transport control according to the third embodiment. Each process of the flowchart of FIG. 16 is executed by the CPU 41 of the control unit 61 shown in FIG. 3 based on the transport control program stored in the memory 68.

Step S31: At the same time as printing the colorimetric pattern, the marker patterns X1 to X5 are printed out of the colorimetric pattern range in the main scanning direction A. The conveyance and printing of the print medium M are repeatedly executed until the printing is completed.
Step S32: An ink drying process is performed by the drying heater 17.
Step S33: The print medium M is transported at the return speed V1 including the transport error in the rewind direction until the range of the two-dimensional sensor 20 reaches the center pattern X4 of the marker patterns (X1 to X7) (return speed V1> X1). V2).
Step S34: The marker pattern is detected by the two-dimensional sensor 20.
Step S35: It is determined whether or not the marker pattern (X1) is located downstream from the sub-scan center of the first line of the colorimetric patch.
Step S36: The colorimetric patch 1 is determined from the center coordinates of the imaging range 20a of the two-dimensional sensor 20 because it is determined that the marker pattern (X1) is located downstream from the sub-scan center of the first line of the colorimetric patch (step S35: Yes). The distance to the center coordinate of the line is calculated, and the print medium M is transported in the printing direction (the distance is calculated according to the number of the marker pattern).
Step S37: The colorimetric patterns are sequentially read, the colorimetry for all patches is performed, and the processing of the flowchart in FIG. 16 ends.
Step S38: Since it is determined that the marker pattern (X2 to X7) is located upstream from the sub-scan center of the first line of the colorimetric patch (Step S35: No), the center coordinates of the detected marker pattern and the "colorimetric pattern" The distance from the center coordinates of the first row to the center coordinates of the marker pattern X1 arranged downstream is calculated. Then, the print medium is transported in the rewinding direction at the return speed V2 (return speed V1> X1). Thereafter, the process returns to step S34.

(Effects of Third Embodiment)
Thus, by arranging the marker patterns (X1 to X7) on the side of the colorimetric pattern P (outside the colorimetric pattern image range in the main scanning direction), many marker patterns long in the main scanning direction can be arranged, and The return control margin can be secured, and the conveyance accuracy of the print medium M can be improved. In addition, it is possible to minimize the amount of media consumed for adjustment while ensuring a control margin (the marker pattern can be arranged at a minimum downstream of the colorimetric pattern).

  Further, in the case of the third embodiment, a larger margin for adjustment can be obtained as compared with the above-described second embodiment. This eliminates the need for high-precision rewind control (rough control is possible), and enables the print medium M to be transported at a higher speed than the transport speed during normal pattern position detection return control. be able to. For this reason, when the rewind distance is long, the rewind processing can be performed in a short time.

  Finally, the above-described embodiments have been presented by way of example, and are not intended to limit the scope of the present invention. This new embodiment can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. For example, each of the above-described embodiments is an example in which the present invention is applied to an ink jet recording apparatus. However, the present invention can also be applied to an electrophotographic apparatus. The embodiments and the modifications of the embodiments are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

REFERENCE SIGNS LIST 1 guide rod 5 carriage 6 recording head 8 main scanning motor 9 driving pulley 10 pressure pulley 11 timing belt 45 recording head 47 two-dimensional sensor 61 control unit 62 transport unit 63 sub-scanning motor 64 winding unit 65 winding motor 66 paper feed Unit 67 paper feed motor 68 memory 100 inkjet recording device M print medium

Japanese Patent No. 4978278

Claims (8)

An image forming apparatus having a color measurement function of performing color measurement based on a read captured image by reading a color measurement pattern including a plurality of color measurement patches recorded on a recording material,
A transport unit that transports the recording material,
On the recording material, a plurality of marker patterns are provided on the side of the colorimetric pattern, and the distance between the marker patterns is a predetermined distance, respectively, and the downstream side of the first line of the colorimetric pattern. A printing unit that records so as to include the downstream marker pattern located at
The recording is performed until the colorimetric pattern on the recording material is located at a reading position by the imaging device based on a distance between the plurality of marker patterns and the colorimetric pattern in the transport direction of the recording material. A control unit configured to control a conveyance unit to convey the material, and to control the imaging device to read the colorimetric pattern of the conveyed recording material. The control unit includes:
Any one of the plurality of marker patterns is transported and controlled to transport the recording material until it is located at the reading position, and is also read by an imaging device, and any of the marker patterns is detected. And controlling the transport of the transport unit so as to transport the recording material until the marker pattern recorded on the downstream side of the colorimetric pattern is located at a reading position based on the detection result. 2. The image forming apparatus according to 1. The plurality of marker patterns can be identified with respect to the colorimetric pattern by a pattern shape and an arrangement position of the printing unit with respect to a main scanning direction which is a scanning direction of the printing unit. The image forming apparatus as described in the above. The controller is configured to convey the recording material until the marker pattern recorded on the downstream side of the colorimetric pattern is positioned at a reading position, and then to convey the recording material in a printing direction. The image forming apparatus according to any one of claims 1 to 3, wherein a position of the center of the colorimetric pattern and an imaging range of the imaging device are aligned by controlling the transport of the unit. apparatus. The control unit controls the transport of the transport unit so as to transport the recording material to the reading position of the image capturing device in the first transport control, and the captured image captured by the image capturing device The distance from any of the marker patterns detected from the marker pattern to the marker pattern recorded on the downstream side of the colorimetric pattern is calculated, and in the second transport control, the calculated distance is calculated based on the calculated distance. 5. The image forming apparatus according to claim 4, wherein the transport unit controls transport of the recording material to a position at which the image capturing apparatus captures the colorimetric pattern. The said control part performs conveyance control of the said conveyance part so that the conveyance speed of the said 1st conveyance control may become faster than the conveyance speed of the said 2nd conveyance control. An image forming apparatus according to claim 1. A transport control method for an image forming apparatus having a colorimetric function of reading a colorimetric pattern including a plurality of colorimetric patches recorded on a recording material by an image capturing apparatus and performing colorimetry based on the read captured image. ,
A transport unit transports the recording material,
A printing unit, on the recording material, a plurality of marker patterns on a side of the colorimetric pattern, and a distance between the marker patterns is a predetermined distance, respectively, and one line of the colorimetric pattern A printing step of recording so as to include a downstream marker pattern located downstream of the eyes,
A control unit that controls, based on a distance between the plurality of marker patterns and the colorimetric pattern in the transport direction of the recording material, until the colorimetric pattern on the recording material is located at a reading position by the imaging device; Controlling the transport of a transport unit to transport the recording material, and controlling the imaging device to read the colorimetric pattern of the transported recording material. An image forming apparatus having a colorimetric function of reading a colorimetric pattern including a plurality of colorimetric patches recorded on a recording material by an imaging device and performing colorimetry based on the read captured image, A transfer control program for causing a computer to execute transfer control,
Said computer,
A transport unit that transports the recording material,
On the recording material, a plurality of marker patterns are provided on the side of the colorimetric pattern, and the distance between the marker patterns is a predetermined distance, respectively, and the downstream side of the first line of the colorimetric pattern. A printing unit that records so as to include the downstream marker pattern located at
The recording is performed until the colorimetric pattern on the recording material is located at a reading position by the imaging device based on a distance between the plurality of marker patterns and the colorimetric pattern in the transport direction of the recording material. A transfer control program that controls the transfer of a transfer unit to transfer a material, and causes the control unit to control the imaging device to read the colorimetric pattern of the transferred recording material.

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