JP2009101697A - Recording device and recording position adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording device which can simply set adjusting values of recording positions by recording agents when the recording agents of different detecting sensitivities by optical sensors are used, and a method for setting the recording position adjusting value and a recording method. <P>SOLUTION: The adjusting values of the recording positions by light magenta, yellow, and magenta inks having low detecting sensitivities of the optical sensors are set by substituting for the adjusting values of the recording positions by cyan, light cyan, and black inks having high detecting sensitivities. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a recording position adjustment pattern recorded on a recording medium is detected by an optical sensor, and based on the detection result, an adjustment value for adjusting a recording position for each different recording agent can be acquired and dealt with. The present invention relates to a recording apparatus and a recording position adjusting method.

  Conventionally, print position alignment (recording position adjustment) in this type of printing apparatus (recording apparatus) is usually performed as follows. For example, in print position alignment of forward scanning (forward path recording) and backward scanning (return path recording) in reciprocal recording, or print position alignment between recording heads when using a plurality of recording heads, or by forward scanning and backward scanning, or A plurality of recording heads record ruled lines as recording position adjustment patterns on a print medium. When printing the ruled lines, the relative print conditions are varied by adjusting the print timing (recording timing) between forward scanning and backward scanning or between a plurality of recording heads. Then, a user or the like observes the print result, selects a ruled line recorded under the print condition with the best print position, and print device or host computer based on the print condition when the ruled line is recorded In addition, print conditions for print position alignment are set as recording position adjustment values. However, such a conventional print alignment method is complicated because the user or the like must select the alignment condition by looking at the print result and set the condition.

  Therefore, Japanese Patent Application Laid-Open No. 2004-151561 describes a technique for dealing with a recording position adjustment pattern by reading it with an optical sensor. In other words, regarding the first print and the second print (prints at the time of forward scanning and backward scanning, or printing by a plurality of heads, respectively) as print position alignment targets, recordings in which their relative print position shift amounts are different. The position adjustment pattern is recorded on the print medium. Then, optical characteristics such as reflection density are measured for each of the recorded adjustment patterns using an optical sensor composed of a light emitting part (generally an LED) and a light receiving part (generally a phototransistor). Then, based on the result, the condition for print alignment between the first and second prints is determined.

  Further, in a printing apparatus capable of recording a multicolor image, it is common to use printing agents (recording agents) of cyan, magenta and yellow tones in addition to black. Some printing apparatuses use ink such as light cyan or light magenta in order to reduce the graininess of dots formed by ink landing on the print medium. When a print alignment pattern (recording position adjustment pattern) is formed using a print agent having a plurality of different color tones, a color filter is provided in the light emitting portion of the optical sensor to form any print tone. With respect to the pattern, a technique for measuring a good optical characteristic of the pattern by increasing the S / N ratio at the time of measuring the optical characteristic of the portion where the dot is formed and the portion where the dot is not formed has also been proposed ( Patent Document 2).

Japanese Patent Laid-Open No. 10-329381 JP 2001-105635 A

  According to these techniques, it is possible to easily perform print alignment without bothering the user. However, in a printing apparatus using a printing agent (recording agent) having a different color tone, a light source having a wide wavelength region as a light emitting unit of an optical sensor, a color filter for limiting the wavelength region, and switching of the color filter associated therewith are controlled. There is a problem that a mechanism is required, which increases costs and increases the size of the apparatus.

  An object of the present invention is to provide a recording apparatus and a recording position adjusting method that can easily set and cope with an adjustment value of a recording position by using a recording agent having different detection sensitivities by an optical sensor. There is to do.

  The recording apparatus of the present invention scans a recording head having a first nozzle for discharging the first color ink and a second nozzle for discharging the second color ink in the forward direction and the backward direction. In the recording apparatus for recording an image on a recording medium, the adjustment for adjusting the relative displacement of the recording position in the backward scanning with respect to the recording position in the forward scanning with respect to the first nozzle is performed. Control means for causing the recording head to record a pattern for obtaining a value on the recording medium, an optical sensor for detecting optical characteristics of the pattern recorded on the recording medium, and a detection result of the optical sensor Setting means for setting the adjustment value of the first nozzle based on the first sensor, and the detection accuracy of the ink of the first color by the optical sensor is a predetermined detection. The detection accuracy of the second color ink by the optical sensor is less than a predetermined detection accuracy, and the setting means sets the adjustment value of the second nozzle to the adjustment value of the first nozzle. It is characterized in that an adjustment value is substituted.

  The recording position adjusting method of the present invention is a recording position adjusting method for a recording head having a first nozzle for ejecting a first color ink and a second nozzle for ejecting a second color ink. The pattern for acquiring an adjustment value for adjusting a relative deviation of the recording position in the scanning in the backward direction with respect to the recording position in the scanning in the forward direction is acquired by the recording head with respect to the first nozzle. A pattern recording step for recording on a recording medium, a detection step for detecting optical characteristics of the pattern recorded on the recording medium by an optical sensor, and the detection result of the optical sensor based on the detection result of the first nozzle. A setting step of setting an adjustment value, and the detection accuracy of the ink of the first color by the optical sensor is equal to or higher than a predetermined detection accuracy, and the optical sensor The detection accuracy of the second color ink is less than a predetermined detection accuracy, and the adjustment value of the second nozzle is substituted with the adjustment value of the first nozzle in the setting step. And

  In this specification, “printing (recording)” is manifested not only in the case of forming significant information such as characters and figures but also so that humans can perceive it visually, regardless of significance. Regardless of whether or not the image is a print medium (recording medium), an image, a pattern, a pattern, or the like is widely formed or the medium is processed.

  Here, “print medium (recording medium)” refers not only to paper used in general printing apparatuses, but also to materials that can accept ink, such as cloth, plastic film, and metal plate.

  Furthermore, “ink” is to be interpreted widely as the definition of “print” above, and is also referred to as a printing agent or a recording agent, and is applied on a print medium to form an image, a pattern, a pattern, or the like. Or a liquid that can be used for processing a print medium.

  Further, in this specification, as optical characteristics, optical density, that is, reflection optical density using reflectance and transmission optical density using transmittance are used. However, optical reflectivity, reflected light intensity, etc. can also be used. In this specification, unless there is a particular confusion, the reflection optical density is abbreviated as optical density or simply density.

  According to the present invention, when recording agents having different detection sensitivities by the optical sensor are used, the adjustment value of the recording position by the recording agent having a low detection sensitivity is used instead of the adjustment value of the recording position by the recording agent having a high detection sensitivity. By setting, it is possible to easily set the adjustment value of the recording position with various different recording agents.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the case where the present invention is applied mainly to an inkjet printing apparatus (inkjet recording apparatus) and a printing system (recording system) using the inkjet printing apparatus will be described.

(1) Basic Configuration First, the basic configuration of the inkjet printing apparatus of the present invention will be described. Here, an ink jet recording type printer (ink jet printer) will be described as an example.

(1-1) First Configuration Example of Main Part FIG. 1 is a schematic perspective view for explaining a first configuration example of a main part of an inkjet printing apparatus to which the present invention can be applied.
In FIG. 1, a plurality (four) of head cartridges 1A, 1B, 1C, 1D are mounted on the carriage 2 in a replaceable manner. Each of the head cartridges 1A to 1D has a print head unit (recording head unit) and an ink tank unit, and is provided with a connector for transmitting and receiving a signal for driving the head unit. In the following description, when the whole or any one of the head cartridges 1A to 1D is shown, the print head 1 or the head cartridge 1 is simply indicated.

  The plurality of head cartridges 1 perform printing using inks of different colors, and different inks such as black, cyan, magenta, and yellow are respectively stored in the ink tank portions. Each head cartridge 1 is mounted on the carriage 2 so as to be replaceable. A connector holder (electrical connection part) for transmitting a drive signal or the like to each head cartridge 1 via the connector is provided on the carriage 2. Is provided.

  The carriage 2 is guided so as to reciprocate in the main scanning direction along a guide shaft 3 extending in the main scanning direction indicated by an arrow X and installed in the apparatus main body. The carriage 2 is driven by a main scanning motor 4 through driving mechanisms such as a motor pulley 5, a driven pulley 6, and a timing belt 7, and its position and movement are controlled. A print medium (recording medium) 8 such as a print sheet or a plastic thin plate opposes the ejection port surface (ink ejection port formation surface) of the head cartridge 1 by the rotation of the two pairs of transport rollers 9, 10 and 11, 12. The sheet is conveyed (paper fed) in the sub-scanning direction indicated by the arrow Y through the position (printing unit). The back surface of the print medium 8 is supported by a platen (not shown) so as to form a flat print surface in the print unit. The discharge port surface of each head cartridge 1 mounted on the carriage 2 protrudes downward from the carriage 2 and is parallel to the surface of the print medium 8 between the two pairs of transport rollers 9, 10 and 11, 12. To be held. A reflection type optical sensor 30 is attached to the carriage 2.

  The head cartridge 1 is an ink jet head cartridge that discharges ink using thermal energy, and includes an electrothermal transducer (heater) for generating thermal energy. In other words, the print head portion of the head cartridge 1 causes ink to boil by the thermal energy generated by the electrothermal transducer, and uses the foaming energy to eject the ink from the ejection port toward the print medium 8.

  Reference numeral 14 denotes a recovery processing unit that performs a recovery process for maintaining a good ink discharge state in the print head unit of the head cartridge 1. The recovery processing unit 14 includes a cap 15 for capping the discharge port portion of the print head unit, a suction pump 16 connected to the cap 15 by a pipe 27, and a wiper blade 18 held by a holder 17. Is provided.

(1-2) Second Configuration Example of Main Part FIG. 2 is a schematic perspective view for explaining a second configuration example of a main part of an inkjet printing apparatus to which the present invention can be applied. In FIG. 2, since the part which attached | subjected the code | symbol same as FIG. 1 has the same function as FIG. 1, the description is abbreviate | omitted.

  In FIG. 2, a plurality (six) of head cartridges 41A, 41B, 41C, 41D, 41E, and 41F are mounted on the carriage 2 in a replaceable manner. Each of the cartridges 41A to 41F is provided with a connector for receiving a signal for driving the print head unit. In the following description, when referring to the whole or any one of the head cartridges 41A to 41F, the print head 41 or the head cartridge 41 is simply indicated. The plurality of head cartridges 41 print using different colors of ink, and the ink tanks store different inks such as black, cyan, magenta, yellow, light cyan, and light magenta. Yes. Each head cartridge 41 is mounted on the carriage 2 so as to be replaceable. A connector holder (electrical connection) for transmitting a drive signal or the like to each head cartridge 41 via the connector is mounted on the carriage 2. Part).

(1-3) Recording Unit The recording unit includes a carriage 2 that is movably supported by a guide shaft 3 and a head cartridge 1 (41) that is detachably mounted on the carriage 2.

  3 to 5 are diagrams for explaining a specific configuration example of the head cartridge 1 (41). As shown in FIG. 3, the head cartridge 1 (41) of this example includes an ink tank H1900 that stores ink, and a print head that discharges ink supplied from the ink tank H1900 from an ejection port according to recording information ( Recording head) H1001. The print head H1001 is a so-called cartridge system that is detachably mounted on the carriage 2. The head cartridge 1 (41) of this example has, as an ink tank H1900, for example, black, light cyan, light magenta, cyan, magenta, and yellow in order to make it possible to record a photographic-tone high-quality color image. Ink tanks for independently storing the inks are prepared, and each is detachable from the print head H1001 as shown in FIG.

  As shown in the exploded perspective view of FIG. 5, the print head H1001 includes a plurality of recording element substrates H1100, a first plate H1200, an electric wiring substrate H1300, a second plate H1400, a tank holder H1500, a flow path forming member H1600, It comprises a filter H1700 and a seal rubber H1800.

  In the recording element substrate H1100, a plurality of recording elements for ejecting ink and electric wiring such as Al for supplying power to each recording element are formed on one side of the Si substrate by a film forming technique. A plurality of ink flow paths and a plurality of ejection openings H1100T corresponding to the elements are formed by a photolithography technique. In addition, ink supply ports for supplying ink to the plurality of ink flow paths are formed to open on the back surface of the Si substrate. The recording element substrate H1100 is bonded and fixed to the first plate H1200, and an ink supply port H1201 for supplying ink to the recording element substrate H1100 is formed therein. Further, a second plate H1400 having an opening is bonded and fixed to the first plate H1200, and the electric wiring substrate H1300 is electrically connected to the recording element substrate H1100 via the second plate H1400. Is held to be connected. The electrical wiring substrate H1300 applies an electrical signal for ejecting ink to the recording element substrate H1100. The electrical wiring substrate H1300 is located at an end portion of the electrical wiring and corresponds to the electrical wiring from the main body. It has an external signal input terminal H1301 for receiving signals, and the external signal input terminal H1301 is positioned and fixed on the back side of the tank holder H1500.

  On the other hand, a flow path forming member H1600 is fixed to a tank holder H1500 that detachably holds the ink tank H1900, for example, by ultrasonic welding, and an ink flow path H1501 extending from the ink tank H1900 to the first plate H1200 is formed. is doing. Further, a filter H1700 is provided at the end of the ink flow path H1501 that engages with the ink tank H1900 on the ink tank side so as to prevent dust from entering from the outside. Further, a seal rubber H1800 is attached to the engaging portion with the ink tank H1900, and the ink is prevented from evaporating from the engaging portion.

  A tank holder portion composed of a tank holder H1500, a flow path forming member H1600, a filter H1700, and a seal rubber H1800, and a recording composed of a recording element substrate H1100, a first plate H1200, an electrical wiring substrate H1300, and a second plate H1400. The element portions constitute a recording head H1001 by being bonded by bonding or the like.

(1-4) Specific Nozzle Configuration of Recording Head FIGS. 6 to 8 are explanatory diagrams of specific configuration examples of nozzles formed by the ejection ports H1100T of the recording head H1001.

  In the recording head H (H1001) of this example, a plurality of ejection ports P (H1100T) capable of ejecting ink are formed in two rows (hereinafter also referred to as “nozzle rows”) L1 and L2. The nozzle rows L1 and L2 extend in the sub-scanning direction of the arrow Y where the recording medium is conveyed. In each of the nozzle rows L1 and L2, the discharge ports P constituting the nozzles are formed 128 (128 nozzles) at intervals corresponding to 600 dpi as the pitch Py. Further, the discharge ports P of the nozzle row L1 and the discharge ports P of the nozzle row L2 are shifted by a half pitch (Py / 2) corresponding to 1200 dpi in the sub-scanning direction of the arrow Y. An arrow X is the main scanning direction in which the recording head H reciprocates. Then, by ejecting the same color ink from a total of 256 ejection openings P in these two rows, an image can be recorded with a dot density in the sub-scanning direction of 1200 dpi. Accordingly, the recording resolution in the sub-scanning direction is twice that when only one of the nozzle rows L1 and L2 is provided.

  In the case of this example, the recording head H configured as described above has six types of ink to be ejected, that is, cyan (C), magenta (M), yellow (Y), and black (K) ink, as shown in FIG. , Light cyan (LC) and light magenta (LM) inks are combined in total. Two of the six recording heads H combined in this way are configured on the same chip. C1 and C2 are nozzle arrays LM1 and LM2 for ejecting cyan (C) ink, nozzle arrays for ejecting light cyan (LC) ink, and K1 and K2 are ejecting black (K) ink. Nozzle rows, Y1 and Y2 are nozzle rows for ejecting yellow (Y) ink, LC1 and LC2 are nozzle rows for ejecting light cyan (LC) ink, and M1 and M2 are magenta (M) ink. It is a nozzle row for discharging. In FIG. 7, the number of ejection ports P that eject ink of each color is represented as a total of 16 nozzle numbers R0 to R15. Cyan (C), magenta (M), yellow (Y), and black (K) inks are dark inks having a relatively high dye density, and light cyan (LC) and light magenta (LM) inks are dark inks. A light ink having a relatively low dye concentration of 1/6 of In this way, a color image can be recorded by ejecting different inks for each recording head H in which the two nozzle rows L1 and L2 are formed.

  In FIG. 8, h is a heater (electrothermal converter), which generates thermal energy used as the ejection energy of the ink droplet I ′ in accordance with the drive signal. Film boiling occurs in the ink I in the nozzle by the thermal energy of the heater h, and the ink droplet I ′ is ejected from the ejection port P by the foaming energy at that time.

(1-5) Optical Sensor FIG. 9 is a schematic diagram for explaining the reflective optical sensor 30 shown in FIGS. 1 and 2.
The reflection type optical sensor 30 is attached to the carriage 2 as described above, and has a light emitting unit 31 and a light receiving unit 32. Light (incident light Iin) 35 emitted from the light emitting unit 31 is reflected by the print medium 8, and the reflected light (Iref) 37 can be detected by the light receiving unit 32. The detection signal (analog signal) of the reflected light 37 is transmitted to a control circuit on the electric board of the printing apparatus via a flexible cable (not shown), and converted into a digital signal by an A / D converter in the control circuit. The The position where the optical sensor 30 is attached to the carriage 2 is set to a position shifted from the locus on which the ejection port of the recording head H moves during print scanning in order to prevent adhesion of droplets of ink or the like. As this optical sensor 30, a sensor having a relatively low resolution can be used, thereby reducing the cost.

(1-6) Configuration Example of Control Circuit FIG. 10 is a block diagram for explaining a configuration example of a control circuit in such an ink jet printing apparatus.
In FIG. 10, a controller 100 as a main control unit is provided with, for example, a CPU 101 in the form of a microcomputer, a ROM 103 storing programs, required tables and other fixed data, an area for developing image data, a work area, and the like. RAM 105 is provided. The CPU 101 executes processing for print position alignment (recording position adjustment) described later. The adjustment value for the recording position adjustment is set by the process for the print position alignment (recording position adjustment), and the adjustment value is used in the actual recording process after that to be used for the adjustment of the recording position. Become. The host device 110 is a supply source of image data, and may be a computer that creates and processes data such as images related to printing, or may be in the form of a reader unit for reading images. Image data, other commands, status signals, and the like are transmitted / received to / from the controller 100 via the interface (I / F) 112.

  The operation unit 120 is a group of switches that accepts an instruction input by an operator, and includes a power switch 122, a switch 124 for instructing start of printing, and a recovery for instructing activation of a suction recovery operation for the recording head H (H1001). A switch 126, a registration adjustment start switch 127 for manually performing registration adjustment (recording position adjustment), a registration adjustment value setting input unit 129 for inputting an adjustment value of manual registration, and the like. The sensor group 130 is a sensor group for detecting the state of the apparatus. The reflective optical sensor 30, the photocoupler 132 for detecting the home position, and a temperature provided at an appropriate part for detecting the environmental temperature. A sensor 134 and the like.

  The head driver 140 is a driver that drives the discharge heater 25 (h) of the print head 1 or 41 according to print data or the like. The head driver 140 operates the discharge heater 25 (h) in synchronization with a shift register that aligns print data corresponding to the position of the discharge heater 25 (h), a latch circuit that latches at appropriate timing, and a drive timing signal. In addition to the logic circuit element, it has a timing setting section for appropriately setting the drive timing (discharge timing) for dot formation position alignment. The recording heads 1 and 41 are provided with sub heaters 142. The sub-heater 142 performs temperature adjustment for stabilizing the ink discharge characteristics, and is formed on the print head substrate at the same time as the discharge heater 25 (h) and / or attached to the print head main body or head cartridge. It can be. The motor driver 150 is a driver that drives the main scanning motor 5, the sub-scanning motor 162 is a motor that is used for transporting (moving in the sub-scanning direction) the print medium 8, and the motor driver 160 is the driver. .

(1-7) Print Pattern for Print Positioning In the following description, the ratio of the area printed by the printing apparatus to the predetermined area on the print medium is referred to as “area factor”. For example, the area factor is 100% if dots are formed throughout a predetermined area on the print medium, 0% if no dots are formed at all, and the area if the printed area is half the area of the area The factor is 50%.

  FIGS. 11A, 11 </ b> B, and 11 </ b> C are schematic diagrams for explaining an example of a print pattern (recording position adjustment pattern) for print position alignment. The print pattern of this example shows the dot formation position (recording position) during forward recording (forward scanning) and the dot formation position (recording position) during backward recording (reverse scanning) when bidirectional recording is performed. Is a pattern for acquiring the adjustment value of the recording position between.

  11A, 11B, and 11C, white dots 700 are dots formed on the print medium 8 during forward scanning (first printing), and hatched dots 710 are backward scanned ( The dots formed during the second printing) are shown. The presence or absence of hatching in the dots 700 and 710 is for convenience of explanation. In this example, the dots 700 and 710 are dots formed by ink ejected from the same recording head, and the color or darkness of the dots. It does not correspond to. FIG. 11A shows dots formed when the print positions in the forward scan and the backward scan are matched. FIG. 11B shows a case where the print position is slightly shifted, and FIG. The dots formed when the print position is further shifted are shown.

  As is apparent from FIGS. 11A to 11C, in this example, complementary dots are formed in each of the reciprocating scans. That is, in the forward scan, the odd-numbered row Lo dots 700 are formed, and in the backward scan, the even-numbered row Le dots 710 are formed. Therefore, as shown in FIG. 11A, when the respective dots 700 and 710 are recorded with a deviation of approximately one dot diameter, the print positions in the reciprocating scan are in alignment. In this print pattern, the density of the entire print portion decreases as the print position shift increases. That is, the area factor is approximately 100% within the range of the patch as the print pattern in FIG. As shown in FIGS. 11B to 11C, as the print position is shifted, the overlap between the forward scanning dot 700 and the backward scanning dot 710 increases, and the area where no dot is formed, that is, the dot is covered. The area that is not spread. As a result, the area factor decreases and the overall average density decreases.

  In this example, by shifting the print timing, the print positions for the forward scan and the backward scan are shifted to print the print pattern for print position alignment. The print pattern for print position alignment in which the print position is shifted can also be realized by shifting the data on the print data. In FIGS. 11A to 11C, the dots 700 and 710 are formed in units of one dot in the main scanning direction. However, they are arranged for each appropriate number of units according to the accuracy of print alignment. Can be formed.

12A, 12B, and 12C are explanatory diagrams when dots 700 and 710 are formed every four dots.
In FIG. 12, FIG. 12A shows a state in which the print positions of the dots 700 and 710 are aligned, FIG. 12B shows a slightly shifted state, and FIG. 12C shows a further shifted state. Indicates the state. The intent of these patterns is to reduce the area factor while the reciprocal print positions deviate from each other. This is because the density of the print portion strongly depends on the change of the area factor. That is, the density increases due to the overlapping of the dots 700 and 710, but the increase in the area where the dots are not printed has a greater influence on the average density of the entire print unit.

  FIG. 13 shows the relationship between the shift amount of the print position and the reflection optical density in the print patterns shown in FIGS. 11 (A) to 11 (C) and FIGS. 12 (A) to 12 (C) of this embodiment. It is explanatory drawing of.

  In FIG. 13, the vertical axis represents the reflection optical density (OD value), and the horizontal axis represents the print position deviation amount (μm). When incident light (Iin) 35 and reflected light (Iref) 37 in FIG. 9 are used, reflectance R = Iref / Iin and transmittance T = 1−R. If the reflection optical density is d, there is a relationship R = 10−d. As described above, since the area factor is 100% when the amount of print position deviation of the dots 700 and 710 is “0”, the reflectance R is the smallest. That is, the reflection optical density d is maximized. Even if the print positions of the dots 700 and 710 are relatively shifted in either the + or − direction (the direction of the arrow X in FIGS. 11 and 12), the reflection optical density d decreases.

(1-8) Print Position Alignment Processing FIG. 14 is a flowchart for explaining print position alignment processing (recording position adjustment processing).
First, a print pattern for print alignment is printed (step S1). Next, the optical characteristics of the print pattern are measured by the optical sensor 30 (step S2). Based on the measured optical characteristics of the print pattern, an appropriate print alignment condition is obtained (step S3). The alignment condition can also be obtained by curve approximation. Then, according to the print position parameter corresponding to the alignment condition, the recording head drive timing is changed to adjust the dot formation position (step S4).

  FIG. 15 is an explanatory diagram when a print pattern as shown in FIGS. 12A to 12C is printed on the print medium 8.

  In the case of this example, nine print patterns 61 to 69 having different relative shift amounts of print positions are printed in forward scan and reverse scan printing. Each printed pattern is also referred to as a patch, for example, a patch 61, 62 or the like. Print position parameters corresponding to the patches 61 to 69 are represented as (a) to (i), respectively. In these nine patterns 61 to 69, for example, the forward scan is fixed as the print start timing of the forward scan and the backward scan. On the other hand, the reverse scan start timing is printed by a total of nine timings: a currently set start timing, four earlier start timings, and four later start timings. Such setting of the print start timing and printing of the nine patterns 61 to 69 based on the print start timing can be executed by a program activated by a predetermined instruction input.

  After recording the patches 61 to 69 as print patterns in this way, the print medium 8 and the carriage 2 are moved so that the optical sensor 30 mounted on the carriage 2 is positioned at the opposite position. The optical characteristics of the respective patches 61 to 69 are measured with the carriage 2 stationary. Thus, by measuring the optical characteristics while the carriage 2 is stationary, the influence of noise due to the driving of the carriage 2 can be avoided. Further, the size of the measurement spot of the optical sensor 30 can be increased with respect to the dot diameter, for example, by increasing the distance between the sensor 30 and the print medium 8. As a result, it is possible to average the variation in local optical characteristics (for example, reflection optical density) on the printed pattern and to measure the reflection optical density with high accuracy.

(2) One Embodiment of Characteristic Configuration Next, one embodiment of a characteristic configuration of the present invention will be described.
(2-1) Optical Sensor As the optical sensor 30 in the present embodiment, an appropriately selected color can be used according to the color tone of the printing agent such as ink used in the printing apparatus, the configuration of the recording head, and the like. . In other words, for example, a printing agent having a color tone with excellent light absorption characteristics with respect to the color of a red light emitting diode (LED) is used as the light emitting unit 31, and the recording head corresponding to the printing agent is subjected to adjustment of print alignment. And

Hereinafter, the measurement principle using the optical characteristics of the irradiation light of the light emitting unit 31 will be described with reference to FIGS.
FIG. 16A shows the color wavelength characteristics of a red light emitting diode as the light emitting unit 31. This represents the color of the light source and the light intensity. In the figure, the region around 450 nm of the wavelength is blue, 550 nm is green, and 610 nm is red. FIG. 16B shows the wavelength characteristics of the reflectance of a print medium on which dots are not formed. This is due to the color of the portion of the print medium where no dots are formed. FIG. 16C shows the wavelength characteristic of the light absorptance of a print medium on which dots are not formed. This is obtained by subtracting the reflectance from 100%, and as in FIG. 16B, this is due to the color of the portion of the print medium where no dots are formed. FIG. 16D shows the wavelength characteristics of the reflected light from the print medium. This shows the relationship between the color of reflected light and the intensity of light.

  As shown in FIGS. 16B and 16C, the print medium used in this embodiment has a high reflectivity over the entire visible region, and thus a low absorption rate. Therefore, the optical characteristic of the reflected light shown in FIG. 16D is slightly reduced due to the light absorption of the print medium with respect to the light intensity, but roughly speaking, the wavelength characteristic does not change so much. The hatched portion in FIG. 16D is a portion that contributes to the measurement output of the element that measures the intensity of light covering the visible region. Actually, the sensitivity characteristic of the measuring element influences. However, in order to make the explanation easy to understand, the explanation is made on the assumption that the area of the shaded portion becomes the measurement result of the optical sensor as it is.

  FIG. 17 to FIG. 20 are explanatory diagrams of measurement results for a portion in which dots of black, cyan, magenta, and yellow ink (printing agent) are formed on a print medium.

  (B) in FIG. 17 to FIG. 20 show the wavelength characteristics of the reflectance of the portion where dots are formed on the print medium using ink of each color. This is due to the coloring of the portion where the dots are formed by the ink of each color. (C) in FIG. 17 to FIG. 20 shows the wavelength characteristics of the absorptance of a portion where dots are formed on the print medium using ink of each color. This is obtained by subtracting the reflectance from 100%, and is due to the color development of the portions where the ink dots of each color are formed, as in FIG. 17B. (D) in FIGS. 17 to 20 shows the wavelength characteristics of the reflected light from the print medium. This shows the relationship between the color and intensity of the reflected light.

  In the case of yellow ink dots, there is a reflectance peak near the wavelength corresponding to the color tone as shown in FIG. 20B, and conversely, the color tone corresponds to the color tone as shown in FIG. It can be seen that the absorption rate in the visible region other than the wavelength is high. Also, in the vicinity of the wavelength of 610 nm, which is the red region, the reflected light intensity of the magenta ink and yellow ink dots is as shown in FIGS. 19 (D) and 20 (D). It becomes strong in the region where the absorption rate is high (see FIGS. 17C and 18C).

  When comparing the hatched portions in FIG. 16 to FIG. 20 (D), the amount of reflected light is greatest when no dots are formed on the print medium (see FIG. 16D). When dots of black ink and cyan ink are formed on the top, the amount of reflected light decreases (see FIGS. 17D and 18D). Further, the reason for the large amount of reflected light when yellow ink dots are formed (see FIG. 20D) is that a wavelength region corresponding to yellow has a wavelength region with low absorption or a wavelength region with high reflectance. It is for having. This characteristic is due to the optical characteristic of yellow ink penetrating and fixing on the print medium and coloring. The same applies to magenta ink.

  Due to such characteristics, when the reflection optical density is measured and the output difference is compared between the portion where the ink dots are not formed and the portion where the dots are formed with each color ink, no dots are formed. The output difference when the reflection optical density is measured for the portion and the portion where the yellow ink and magenta ink dots are formed is small. As shown in FIGS. 19D and 20D, the amount of reflected light increases in the portions where the yellow ink and magenta ink dots are formed, and the amount of reflected light in the portions where no dots are formed (FIG. 16D This is because the difference from ()) is small. In this way, when the light emitting part that irradiates light of a predetermined wavelength is used, when the reflection optical density of each of the part where the dots are not formed with the ink and the part where the dots are formed with the ink is measured, The output difference due to the sensor may be small.

(2-2) Print Positioning Method In this embodiment, as described above, the print position adjusting method (recording position adjusting method) is the first print to be aligned (in the above-described basic configuration example, forward scanning). ) And the second print (reverse scanning in the above-described basic configuration example), first, a plurality of print patterns (recording position adjustment patterns) with different relative print position shift amounts are printed. Thereafter, the optical characteristics such as the reflection density of the print patterns are measured for each pattern by the optical sensor 30, and the print position condition is set based on the measurement result. That is, a print pattern having the optimum print position relationship between the first print and the second print is automatically selected from a plurality of printed print patterns, and the print condition of the selected print pattern is set as the print position condition. . The print position condition is used as a print position adjustment value in the subsequent print operation, and by automatically adjusting the ink discharge timing, the ink discharge amount, etc., it is possible to record without print position deviation.

  In such a print alignment method, as described above, there is a difference in the measurement result of the optical sensor 30 depending on the type of ink, and the contrast between the portion where the dots are formed and the portion where the dots are not formed on the print medium. If it is small, it cannot be detected with high accuracy by the optical sensor 30, and as a result, it may be difficult to accurately align the print positions. For example, in the case of printing a plurality of print patterns in which the shift amounts of the relative print positions of the first print and the second print to be aligned are different, the following problems occur. That is, even if the surface of the print medium is covered with the dot by the first print (forward scan) using yellow ink and the dot by the second print (reverse scan) using the same yellow ink, The measurement result of the reflection optical density of the formed part is difficult to detect accurately because the difference from the part where the yellow ink dots are not formed is not so large. For this reason, the print positions of the first print and the second print are relatively shifted, the yellow ink dots formed during the reciprocating scan overlap, and the portion where the yellow ink dots are not formed is the patch on the print medium. Reflection detected by the optical sensor 30 between the case where the surface is on the surface (there is a portion where the reflection optical density is low) and the case where the surface of the print medium is covered with the first and second print dots using yellow ink. The difference in the measurement result of the light intensity becomes small. Therefore, the amount of change in the measurement result of the optical characteristics such as the reflection density becomes small with respect to the shift amount of the print position due to the first and second prints, and it may be difficult to measure the print position with high accuracy.

  Therefore, in this embodiment, in order to solve such a problem, a printing agent (ink) used for print alignment is specified. That is, ink with a color tone (printing agent) in which the amount of change in the measurement result of optical characteristics such as reflection density is small with respect to the amount of deviation of the print position due to the first and second prints, that is, the measurement of the print position with high accuracy. For a print head using ink of a color tone that makes it difficult to print, the print is not aligned. With respect to the recording head, an adjustment value (recording position adjustment value) for printing position alignment relating to the recording head for discharging ink of other colors is used instead. That is, ink (printing agent) having a large amount of change in the measurement result of the optical characteristics with respect to the amount of deviation of the print position due to the first and second prints, that is, ink having a color tone capable of measuring the print position with high accuracy. An adjustment value (recording position adjustment value) for print alignment relating to the recording head to be used is used instead. As described above, in the present embodiment, as an adjustment value of a recording position by a recording agent (for example, yellow ink) having a relatively low detection accuracy by an optical sensor, a recording agent (for example, a relatively high detection accuracy by an optical sensor). The adjustment value of the recording position by (black ink) is set instead.

  Whether the recording agent has a relatively low detection accuracy by the optical sensor or a relatively high recording agent is determined by the result of detecting the area where no pattern is recorded on the recording medium by the optical sensor and ink. If the difference from the result of detecting the area where the pattern is recorded by the optical sensor is equal to or smaller than a predetermined value, it can be determined that the recording agent has a relatively low detection accuracy. Further, by this determination, the print recording alignment adjustment value obtained from the ink determined to have a relatively low detection accuracy may be set as the print recording alignment adjustment value obtained from an ink different from the ink of the formed pattern. Good. Here, the result detected by the optical sensor may be a received light amount measured by a light receiving element of the optical sensor, or may be a digital signal obtained by A / D converting the received light amount.

Next, a specific description will be given of a print alignment method using the above-described recording head of FIG.
In the present embodiment, a red light emitting diode (LED) is used as the light emitting unit 31 of the optical sensor 30. Therefore, from the viewpoint of the wavelength characteristics described above, the print pattern for print alignment is printed using black (Bk), cyan (C), or light cyan (LC) ink. If magenta (M), light magenta (LM), or yellow (Y) ink is used, sufficient density characteristics and S / It becomes difficult to obtain the N ratio.

  21A, 21 </ b> B, and 21 </ b> C are item numbers (A to H), chip numbers (1 to 3), ink colorant (ink color), adjustment items of the printing apparatus in the present embodiment, FIG. 6 is an explanatory diagram regarding the names of nozzle rows, the ejection characteristics (ejection amount and ejection speed) of ink from each nozzle row, and whether or not print alignment is possible. The position adjustment items for the recording head of FIG. 7 using six colors of ink (printing agent) are ODD-EVEN column adjustment of FIG. 21A, bidirectional adjustment of FIG. 21B, and FIG. There are three adjustments between chips.

  The ODD-EVEN inter-row adjustment (item numbers A to F) is a print alignment between two rows of ejection openings P corresponding to each ink color. In the case of cyan ink, C1 is EVEN. The (even) column and C2 are ODD (odd) columns. In the case of the adjustment between the ODD-EVEN rows, the prints by the ink ejected from the odd-numbered and even-numbered rows of the ejection openings P are respectively the first and second prints, and the relative relationship between these first and second prints. A plurality of print patterns having different print position deviation amounts are printed as patches as shown in FIG. 15 and detected by the optical sensor 30. Bidirectional adjustment (item numbers G to L) is a print position alignment between the print position during forward scanning (forward pass recording) and the print position during backward scan (return pass recording), and forward scan of the recording head. And print position adjustment when bidirectional recording is performed by backward scanning. For example, in the case of cyan ink, during forward scanning, alignment between reciprocating scans can be performed by using the discharge ports P in the C1 (even) row for both sub-scans. In the case of this bidirectional adjustment, the forward and backward scan prints are the first and second prints, respectively, and a plurality of prints in which the relative print position shift amounts of these first and second prints are different. The pattern is printed as a patch as shown in FIG. 15 and is detected by the optical sensor 30. Further, the chip-to-chip adjustment (item numbers G and H) is a print alignment between the chips 1, 2, and 3 (see FIG. 7). In this inter-chip adjustment, the first and second prints are printed by the chips 1 and 2 (chip numbers 1 and 2), or the first and second prints by the chips 2 and 3 (chip numbers 2 and 3), respectively. As the second print, a plurality of print patterns in which the shift amounts of the relative print positions of the first and second prints are different are printed as patches as shown in FIG. 15 and detected by the optical sensor 30. It will be.

  The recording head in the present embodiment is designed so that all the ejection characteristics (ejection amount, ejection speed) are substantially equal for each ink color. In addition, since the recording head is formed by bonding a plurality of (three in the present embodiment) chips 1, 2, and 3, the mounting accuracy of each chip and the amount of variation in heater dimensions between the chips. There is a tendency that the variation in ejection characteristics among chips tends to increase due to the influence of the difference. In the same chip, since it is not affected at least by them, variation in ejection characteristics is small, and stable ejection characteristics can be obtained.

  As described above, due to the wavelength characteristics of the red light emitting diode used as the light emitting unit 31 of the optical sensor 30, the ink (printing agent) that can be aligned with the printing is ink of three colors, cyan, light cyan, and black. For magenta, light magenta, and yellow inks, it is not possible to obtain sufficient density characteristics and S / N ratio with respect to the print position shift amount due to the first and second prints.

  Therefore, with respect to the adjustment items of the recording head using ink that cannot be subjected to such print alignment processing, as shown in FIGS. 22A and 22B, ink that can be subjected to print alignment processing is used and ejected. The print alignment adjustment value for recording heads having substantially the same characteristics is used instead. For example, the ODD-EVEN inter-row adjustment for the light magenta ink of item number B substitutes the adjustment value for cyan ink (item number A) having substantially the same ejection characteristics in the same chip. Similarly, the bidirectional adjustment for the yellow ink of item number J substitutes the adjustment value for the black ink (item number I) in the same chip.

(3) Other Embodiments of Characteristic Configuration Next, other embodiments of the characteristic configuration of the present invention will be described.
The present invention can similarly apply the adjustment value substitution process to a recording head having a configuration as shown in FIG. In the recording head of the present embodiment, nozzle rows corresponding to cyan, magenta, yellow, and black inks (printing agents) are arranged in parallel on the same chip. In addition, the cyan ink ejection port P is located on the nozzle rows C1 and C2 to eject (apply) a relatively large amount of ink, and the cyan ink ejection port P is located on the nozzle rows C3 and C4. A device for ejecting (applying) a small amount of ink is provided. Similarly, the ejection port P for magenta ink is positioned on the nozzle arrays M1 and M2 and ejects (applies) a relatively large amount of ink, and is positioned on the nozzle arrays M3 and M4 for comparison. For ejecting (applying) a small amount of ink. As described above, the nozzles for ejecting different amounts of ink have different areas of the electrothermal transducers (heaters) and ejection port areas.

  24A, 24 </ b> B, and 24 </ b> C are item numbers (A to N) relating to print head adjustment items, ink colorants (ink colors), names of nozzle rows, and nozzle rows in this embodiment. FIG. 5 is an explanatory diagram regarding ink ejection characteristics (ejection amount, ejection speed) and whether or not print alignment is possible. The position adjustment items for the recording head of FIG. 23 using four color inks (printing agents) are the ODD-EVEN row adjustment of FIG. 24A, the bidirectional adjustment of FIG. There are three adjustments between large and small nozzle rows. Adjustment items A to F are ODD-EVEN row adjustments for each color, adjustment items G to L are bidirectional adjustments for each color, and adjustment items M to N are adjustments for large and small nozzle rows. The ODD-EVEN inter-row adjustment and the bi-directional adjustment are the same as in the above-described embodiment. In addition, the adjustment between the large and small nozzles (item numbers M and N) is performed between the nozzle rows C1 and C3 having different cyan ink discharge amounts and between the nozzle rows M1 and M3 having different magenta ink discharge amounts. It is a combination. In the case of the adjustment between the large and small nozzle rows, the prints by the nozzle rows C1 and C3 are the first and second prints, or the prints by the nozzle rows M1 and M3 are the first and second prints. A plurality of print patterns having different print position shift amounts are printed as patches as shown in FIG. 15 and detected by the optical sensor 30.

  The recording head of the present embodiment is provided with nozzle arrays for applying different amounts of ink for cyan ink and magenta ink, and the discharge characteristics of the nozzle arrays that discharge the same ink amount are designed to be substantially equal. Has been. In addition, since the recording head according to the present embodiment has a single chip configuration, variation in ejection performance for each nozzle array in the same chip is small, and stable ejection characteristics can be obtained.

  As described above, due to the wavelength characteristics of the red light-emitting diode used also as the light-emitting portion 31 of the optical sensor 30, the ink (printing agent) capable of print alignment is cyan and black ink. For magenta and yellow inks, it is not possible to obtain sufficient density characteristics and S / N ratio with respect to the amount of displacement of the print position by the first and second prints.

  Therefore, for the adjustment items of the recording head using the ink that cannot be subjected to the print alignment process, as shown in FIGS. 25A, 25B, and 25C, the ink that can be subjected to the print alignment process is used. In addition, an adjustment value for print alignment for a recording head having substantially the same ejection characteristics is used instead. For example, the ODD-EVEN inter-row adjustment relating to magenta (large) of item number B substitutes the adjustment value (item number A) relating to cyan (large) having substantially the same ejection characteristics in the same chip. Similarly, the bidirectional adjustment related to magenta (small) of item number J substitutes the adjustment value (item number H) related to cyan (small) in the same chip.

(Other embodiments)
The present invention does not particularly limit the type of recording agent or recording method, and the configuration of the recording head or recording apparatus. For example, various recording agents such as toner can be used. In addition to the serial scan type as in the above-described embodiment, the recording device may be a so-called full line type using a long recording head extending in the width direction of the print medium.

  The recording position adjustment pattern may be any pattern that can detect the recording result by the optical sensor and acquire the adjustment value of the recording position, and is not specified only in the above-described embodiment. For example, as described above, in addition to the pattern in which the two print positions of the first and second prints are relatively shifted, the pattern in which three or more print positions are relatively shifted, and the recording conditions are variously changed. It may be a pattern, a pattern recorded under predetermined recording conditions, or the like.

1 is a perspective view for explaining a first configuration example of a main part of an ink jet recording apparatus to which the present invention is applicable. It is a perspective view for demonstrating the 2nd structural example of the principal part of the inkjet recording device which can apply this invention. FIG. 3 is a perspective view of the head cartridge in FIGS. 1 and 2. FIG. 4 is an exploded perspective view of the head cartridge in FIG. 3. FIG. 5 is an exploded perspective view when the recording head in FIG. 4 is viewed from below. It is a bottom view of the basic nozzle component of the recording head. It is a bottom view of the principal part of a recording head provided with the basic nozzle structure of FIG. It is an expanded sectional view which follows the VIII-VIII line of FIG. FIG. 3 is an explanatory diagram of a positional relationship between the optical sensor and the print medium in FIGS. 1 and 2. FIG. 3 is a block configuration diagram of a control system of the ink jet recording apparatus of FIGS. 1 and 2. (A), (B), (C) is an explanatory diagram of an example of a recording position adjustment pattern. (A), (B), (C) is explanatory drawing of the other example of the recording position adjustment pattern. It is explanatory drawing of the relationship between the deviation | shift amount of the printing position of a recording position adjustment pattern, and reflective optical density. It is a flowchart for demonstrating a basic recording position adjustment process. It is explanatory drawing of the example of a recording of the pattern for recording position adjustment. (A), (B), (C), (D) is an explanatory diagram of the relationship between the characteristics of the optical sensor used in the embodiment of the present invention and the portion of the recording medium on which no dots are formed. (A), (B), (C), (D) are explanations of the relationship between the characteristics of the optical sensor used in one embodiment of the present invention and the portion of the recording medium on which the black ink dots are formed. FIG. (A), (B), (C), and (D) are explanations of the relationship between the characteristics of the optical sensor used in one embodiment of the present invention and the portion of the recording medium on which cyan ink dots are formed. FIG. (A), (B), (C), (D) are explanations of the relationship between the characteristics of the optical sensor used in one embodiment of the present invention and the portion of the recording medium on which the magenta ink dots are formed. FIG. (A), (B), (C), (D) are explanations of the relationship between the characteristics of the optical sensor used in one embodiment of the present invention and the portion of the recording medium on which the yellow ink dots are formed. FIG. (A), (B), (C) is an explanatory diagram of a specific recording position adjusting method in one embodiment of the present invention. (A), (B) is explanatory drawing of the adjustment value substituted in the recording position adjustment method of FIG. 21 (A), (B). It is a bottom view of the principal part of the recording head used in other embodiment of this invention. (A), (B), (C) is an explanatory diagram of a specific recording position adjusting method in another embodiment of the present invention. (A), (B), and (C) are explanatory diagrams of adjustment values that are substituted in the recording position adjustment method of FIGS. 24 (A), (B), and (C).

Explanation of symbols

1 (1A, 1B, 1C, 1D) Head cartridge 2 Carriage 8 Print medium (recording medium)
30 optical sensor 31 light emitting unit 32 light receiving unit 41 (41A, 41B, 41C, 41D, 41E, 41F) head cartridge H1001, H print head (recording head)
H1100T, P Discharge port H1900 Ink tank

Claims (9)

By causing a recording head having a first nozzle for ejecting ink of the first color and a second nozzle for ejecting ink of the second color to scan in the forward direction and the backward direction, the recording medium is In a recording device for recording images,
For the first nozzle, a pattern for obtaining an adjustment value for adjusting a relative deviation of the recording position in the backward scanning with respect to the recording position in the forward scanning is formed on the recording medium. Control means for recording on the head;
An optical sensor for detecting an optical characteristic of a pattern recorded on the recording medium;
Setting means for setting the adjustment value of the first nozzle based on a detection result of the optical sensor;
The detection accuracy of the first color ink by the optical sensor is equal to or higher than a predetermined detection accuracy, and the detection accuracy of the second color ink by the optical sensor is less than a predetermined detection accuracy,
The recording apparatus is characterized in that the setting means substitutes the adjustment value of the second nozzle with the adjustment value of the first nozzle. The difference between the detection result of the recording medium portion where the first color ink is recorded by the optical sensor and the detection result of the recording medium portion where no ink is recorded by the optical sensor is greater than or equal to a predetermined amount. And
The difference between the detection result of the recording medium portion where the second color ink is recorded by the optical sensor and the detection result of the recording medium portion where the ink is not recorded by the optical sensor is less than a predetermined amount. The recording apparatus according to claim 1, wherein:   The discharge amount of the first color ink discharged from the first nozzle is equal to the discharge amount of the second color ink discharged from the second nozzle. 2. The recording apparatus according to 2.   4. The recording apparatus according to claim 1, wherein the first nozzle and the second nozzle are provided on the same chip of the recording head.   The recording apparatus according to claim 1, wherein the optical sensor is a sensor that emits red light to detect an optical characteristic of the pattern.   The recording apparatus according to claim 1, wherein the first color is black and the second color is yellow.   The recording apparatus according to claim 1, wherein the first color is cyan, and the second color is light magenta.   The recording apparatus according to claim 1, wherein the first color is light cyan and the second color is magenta. In a recording position adjustment method of a recording head having a first nozzle for discharging a first color ink and a second nozzle for discharging a second color ink,
The recording head uses the recording head to record a pattern for obtaining an adjustment value for adjusting a relative shift of the recording position in the backward scanning with respect to the recording position in the forward scanning in the first nozzle. A pattern recording process for recording on a medium;
A detection step of detecting an optical characteristic of a pattern recorded on the recording medium by an optical sensor;
A setting step for setting the adjustment value of the first nozzle based on a detection result of the optical sensor;
The detection accuracy of the first color ink by the optical sensor is equal to or higher than a predetermined detection accuracy, and the detection accuracy of the second color ink by the optical sensor is less than a predetermined detection accuracy,
In the setting step, the adjustment value of the second nozzle is substituted for the adjustment value of the first nozzle.

Images