Recording device

Abstract

To improve the detection accuracy of a fixation state of ink on a medium.SOLUTION: A recording device includes: a recording head that discharges liquid onto a recording medium to form an image; fixing means that heats the liquid discharged by the recording head to fix the image onto the recording medium; reflected light measuring means having a light-emitting part and a light-receiving part capable of measuring the intensity of reflected light of the image; and control means that sets the emission intensity of the light-emitting part and the amplification degree of the light-receiving part of the reflected light measuring means. The control means sets the emission intensity or amplification degree of the reflected light measuring means on the basis of the first reflected light intensity measured by the reflected light measuring means for the image fixed by the fixing means and the second reflected light intensity measured by the reflected light measuring means for the image before being fixed by the fixing means.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a recording apparatus.

Background Art

[0002] In a recording apparatus that forms an image by applying ink to a recording medium, there is one that fixes the image by performing a heat treatment on the recording medium. In such a heat treatment, the greater the amount of heat applied to the recording medium, the more the evaporation of the solvent contained in the ink, the melting of the resin, and the film formation are promoted, and the image tends to be fixed in a short time and surely.

[0003] However, depending on the heating temperature, the molecular structure of the recording medium may change, and the recording medium may be deformed. Therefore, it is preferable to adjust the amount of heat so that suitable fixing is obtained without deforming the recording medium, but such a suitable amount of heat depends on the material of the recording medium. Furthermore, even with the same material, the heat capacity also changes depending on the thickness or size of the recording medium. Therefore, in a recording apparatus that performs heat fixing, it is required to optimize the heat treatment according to the recording medium used, that is, to set an optimal heating temperature for each type of recording medium.

[0004] Patent Document 1 discloses a technique for detecting the fixing state by measuring the reflected light intensity of a printed matter after fixing using a light emitting element and a light receiving element. Patent Document 2 also discloses a configuration in which a laser is irradiated onto an image pattern immediately after printing, and the light amount of the light emitting light source is adjusted by the reflected light.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In Patent Document 1, as a light receiving element, an element in which an output electrical signal changes depending on the intensity of input light such as a photodiode may be used. In practice, a device for detecting the output signal of the light receiving element is required. In such a case, if the intensity of the output light of the light emitting element or the output signal of the light receiving element is not adjusted, due to the constraints of the device, the magnification of the reflected light intensity of the actual printed matter and the detected reflected light intensity may be different, and there is a risk of lacking detection accuracy.

[0007] In addition, in Patent Document 2, there are cases where it is not possible to correctly determine the fixing state because the difference in the specular reflection light intensity detected from the unfixed and fixed image patterns is small, and data that can be judged due to reasons such as the output sticking due to the constraints of the output detection device cannot be obtained.

[0008] The present invention has been made in view of the above problems, and an object thereof is to improve the detection accuracy of the fixing state of ink on a medium.

Means for Solving the Problems

[0009] The recording apparatus according to the present invention includes a recording head that discharges a liquid onto a recording medium to form an image, a fixing unit that heats the liquid discharged by the recording head to fix the image onto the recording medium, a reflected light measuring unit having a light emitting unit and a light receiving unit capable of measuring the intensity of the reflected light of the image, and a control unit that sets the light emission intensity of the light emitting unit and the amplification degree of the light receiving unit of the reflected light measuring unit. The control unit sets the light emission intensity or the amplification degree of the reflected light measuring unit based on a first reflected light intensity measured by the reflected light measuring unit with respect to the image fixed by the fixing unit and a second reflected light intensity measured by the reflected light measuring unit with respect to the image before being fixed by the fixing unit.

Effects of the Invention

[0010] According to the present invention, the detection accuracy of the fixing state of ink on a medium can be improved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0012] (First Embodiment) Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present disclosure, and not all combinations of features described in the following embodiments are essential for the solution means of the present disclosure. The same reference numerals are assigned to the same components.

[0013] <Overall Configuration> FIG. 1 is a perspective view showing the configuration of the recording apparatus 100. FIG. 1(a) is a view showing the overall appearance of the recording apparatus 100. FIG. 1(b) is a view showing a state in which the upper cover 110 of FIG. 1(a) is opened and the internal structure can be seen. The recording apparatus 100 in the present embodiment performs recording by applying ink droplets, which are liquid, onto a recording medium 105 by an inkjet recording method. The recording medium 105 is conveyed with the Y direction as the conveyance direction. The carriage 101 equipped with the recording head 102 reciprocates in the X direction intersecting the Y direction to perform recording. That is, the recording apparatus 100 is an inkjet recording apparatus including a so-called serial type recording head. However, an inkjet recording apparatus including a so-called line type recording head in which a nozzle row is configured over the recording width in the conveyance direction of the recording medium may be used. Also, it may be a multifunctional peripheral device (MFP) in which not only a recording function but also a scanning function, a FAX function, or a transmission function, etc. are integrated. Further, an electrophotographic recording apparatus using powder toner as a recording material may also be used. In the present embodiment, the function of the process for setting the fixing conditions described later is mounted on the recording apparatus 100.

[0014] The recording apparatus 100 includes an input / output unit 109 at the upper part. The input / output unit 109 is configured by, for example, an operation panel. That is, the input / output unit 109 includes a display, and displays, on the display, the remaining ink amount or candidates for the type of the recording medium. The user can select the type of the recording medium or perform recording settings by operating the keys on the operation panel.

[0015] The carriage 101 has an optical sensor 201 (FIG. 2) and a recording head 102 having a discharge port surface provided with discharge ports for discharging the ink supplied from the ink tank 111. The carriage 101 is configured to be reciprocally movable in the X direction (the moving direction of the carriage) along the shaft 104 via the carriage belt 103 by driving of a carriage motor 515 (FIG. 5). In the present embodiment, the recording apparatus 100 can detect the reflected light from the surface of the recording medium 105 by the optical sensor 201.

[0016] A recording medium 105 such as roll paper is conveyed in the Y direction on a platen 106 by a conveying roller (not shown). While the carriage 101 moves in the X direction on the recording medium 105 conveyed onto the platen 106 by the conveying roller, a recording operation is performed by discharging ink droplets from the recording head 102. When the carriage 101 moves to the end of the recording area on the recording medium 105, the conveying roller conveys the recording medium 105 by a certain amount, and moves the recording medium 105 to a position where the recording head 102 can record the area for the next recording scan. Image recording is performed by repeating the above operations. The ink used for image recording in this embodiment is latex ink. By applying heat to the ink, moisture evaporates, the latex resin melts and mixes with the pigment, and a film is formed and cured on the surface of the recording medium. When using a general aqueous ink, the recording medium requires an ink receiving layer for catching the ink and suppressing bleeding. On the other hand, a latex printer can record on a recording medium without an ink receiving layer. In this embodiment, the printed recording medium 105 is conveyed to a fixing device 108. The fixing device 108 is arranged downstream in the Y direction (conveying direction) from the recording area recorded by the recording head 102. The conveyed recording medium 105 is heated in the fixing device 108, the ink is cured, and is discharged from the fixing device 108 in a state where it is fixed on the recording medium (finished state).

[0017] Here, the recording medium used in the signature display industry will be briefly described. In the manufacturing process of the polymer film serving as the recording medium, generally, a process of stretching in a certain direction, called stretching, is performed. At this time, characteristic crystallization called orientation crystallization occurs as the molecules of the film align in a certain direction, and a unique structure called a fiber structure is formed. Such a fiber structure is in a state where the entropy is kept low at normal temperature, but when the temperature exceeds a temperature called the glass transition point, the entropy increases and the amorphous molecules can move. As a result, contraction due to entropy elasticity (rubber elasticity) occurs, causing deformation and a change in rigidity of the film. A recording medium with a glass transition point lower than the heating temperature range of the fixing device 108 is likely to be deformed even when the heating temperature is set to the lowest temperature. Therefore, in the method of determining the fixing temperature from the glass transition point of the recording medium, it is limited to use for a recording medium whose glass transition point is included in the heating temperature range of the fixing device 108. In the present embodiment, an example will be described in which an optimal fixing temperature suppressed to an arbitrary deformation amount can be determined even for a recording medium having a glass transition point lower than the heating temperature range of the fixing device 108. Details will be described later.

[0018] <Carriage Configuration> FIG. 2 is a diagram showing the configuration of the carriage 101. The carriage 101 includes a head holder 202. The carriage 101 is a unit capable of reciprocating in the width direction (X direction) of the recording medium 105. The head holder 202 is a member that holds the recording head 102 and the optical sensor 201, which is a reflection type sensor. As shown in FIG. 2, the position of the optical sensor 201 is configured such that the bottom surface of the optical sensor is at the same position as or higher than the bottom surface of the recording head 102 so as not to contact the recording medium when the carriage moves.

[0019] <Optical Sensor Configuration> FIG. 3 is a schematic cross-sectional view showing the configuration of the optical sensor 201. FIG. 3 shows a cross-section taken along line III-III in FIG. 2. The optical sensor 201 includes a first LED 301, a second LED 302, and a third LED 303 as light-emitting units, and a first photodiode 304, a second photodiode 305, and a third photodiode 306 as light-receiving units that receive light from the light-emitting units. The first LED 301 is a light source having an irradiation angle of normal (90°) with respect to the surface (measurement surface) of the recording medium 105. The first photodiode 304 receives the reflected light that is irradiated from the first LED 301 and reflected from the recording medium 105 at an angle of 45° in the Z direction. That is, the first LED 301 and the first photodiode form an optical system for detecting a so-called diffuse reflection component of the reflected light from the recording medium 105. The angle is not limited to 45°, but 45° is preferable in consideration of the robustness against height variations of the recording head 102 and the like.

[0020] The second LED 302 is a light source having an irradiation angle of 60° in the Z direction with respect to the surface (measurement surface) of the recording medium 105. The first photodiode 304 receives the reflected light that is irradiated from the second LED 302 and reflected from the recording medium 105 at an angle of 60° in the Z direction. That is, the second LED 302 and the first photodiode 304 have the same angle between light emission and light reception, and form an optical system for detecting a so-called specular reflection component of the reflected light from the recording medium 105. The angle is not limited to 60°, but 60° is preferable in consideration of the size of the optical sensor 201 and the signal-to-noise ratio of light reception.

[0021] The third LED 303 is a light source having an irradiation angle of normal (90°) with respect to the surface (measurement surface) of the recording medium 105. The second photodiode 305 and the third photodiode 306 receive the reflected light that is irradiated from the third LED 303 and reflected from the recording medium 105. The light reception amounts of the second photodiode 305 and the third photodiode 306 change according to the distance between the optical sensor 201 and the recording medium 105. Thereby, the distance between the optical sensor 201 and the recording medium 105 can be measured.

[0022] In this embodiment, an example where the optical sensor 201 is installed on the carriage 101 will be described, but other forms are also possible. For example, the optical sensor may be fixedly installed on the recording device 100. Alternatively, a measuring device for measuring the characteristics of a recording medium separate from the recording device 100 may be used, and the characteristics measured by the measuring device may be transmitted to the recording device.

[0023] <Configuration of the fixing device> FIG. 4 is a schematic cross-sectional view showing the configuration of the fixing device 108 for ink fixing. FIG. 4 shows a cross-section taken along line IV-IV in FIG. 1(a). It is assumed that the recording medium 105 is fed into the fixing device 108 from the left side of FIG. 4 and discharged to the right side.

[0024] Inside the chamber 401, an axial-flow blower fan 402 that takes in and blows outside air, and a heater 403 that heats the air blown from the blower fan 402 to make it dry air are provided. The dry air blown from the opening of the chamber 401 contributes to the fixing of the ink. The fixing temperature by the heater 403 can be changed, and based on the flowchart for determining the fixing temperature described later, it is determined to be the optimal heating temperature for the target recording medium 105. The heater 403 includes a temperature sensor 404. Stable heater temperature control is possible by the temperature feedback from the temperature sensor 404. In this example, a non-contact ink fixing configuration using dry air by the combination of the blower fan 402 and the heater 403 is adopted, but a configuration using a contact heater or a radiation heater may also be used.

[0025] <Block diagram> FIG. 5 is a diagram showing the block configuration of the control system of the recording apparatus 100. The ROM 502 is a non-volatile memory, and stores, for example, a control program for controlling the recording apparatus 100 and a program for realizing the operations of the present embodiment. The operations of the present embodiment are realized, for example, by the CPU 501 reading out the program stored in the ROM 502 into the RAM 503 and executing it. The RAM 503 is also used as a working memory of the CPU 501. The EEPROM 504 stores data that should be retained even when the power of the recording apparatus 100 is turned off. At least the CPU 501 and the ROM 502 realize the function as an information processing apparatus that executes the processes described later. The EEPROM 504 stores the characteristic values of each predetermined recording medium and the fixing conditions, etc. The characteristic values and the fixing conditions of each recording medium may be stored not in the storage medium in the recording apparatus 100 but in the ROM of the host computer or an external memory such as a server. And the CPU 501 may perform processing using the information stored externally.

[0026] The interface (I / F) circuit 510 connects the recording apparatus 100 to a network such as an external LAN. The recording apparatus 100 performs transmission and reception of various jobs, data, etc. with devices such as an external host computer via the I / F circuit 510.

[0027] The input / output unit 109 includes an input unit and an output unit. The input unit receives an instruction to turn on the power, an instruction to execute recording, and an instruction to set various functions from the user. The output unit displays various device information such as the power saving mode and a setting screen for various functions that the recording apparatus 100 can execute. In the present embodiment, the input / output unit 109 is an operation panel provided in the recording apparatus 100. The input / output unit 109 is connected to be able to transmit and receive data with the system bus 519 via the input / output control circuit 505. In the present embodiment, the CPU 501 performs notification control of the information of the output unit.

[0028] Further, the input unit may be a keyboard of an external host computer, and may be capable of receiving a user's instruction from the external host computer. The output unit may be an LED display, an LCD display, or a display connected to the host device. When the input / output unit is a touch panel, it is possible to receive an instruction from the user by software keys. Furthermore, the input / output unit 109 may be configured as a speaker and a microphone, and the input from the user may be voice input, and the notification to the user may be voice output.

[0029] When performing measurement by the optical sensor 201, the LED control circuit 507 is driven by the CPU 501, and a predetermined LED in the optical sensor 201 is controlled to light up. Each photodiode of the optical sensor 201 outputs a signal corresponding to the received light, which is converted into a digital signal by the A / D conversion circuit 508 and temporarily stored in the RAM 503. Data to be stored even when the power of the recording apparatus 100 is turned off is stored in the EEPROM 504.

[0030] The recording head control circuit 511 supplies a drive signal corresponding to the recording data to the nozzle drive circuit including a selector and a switch mounted on the recording head 102, and controls the recording operation of the recording head 102 such as the drive order of the nozzles. For example, when recording target data is transmitted from the outside to the I / F circuit 510, the recording target data is temporarily stored in the RAM 503. Then, the recording head control circuit 511 drives the recording head 102 based on the recording data converted from the recording target data into recording data for recording. At this time, the LF (line feed) motor drive circuit 512 drives the LF motor 513 based on the bandwidth of the recording data and the like, and the conveyance roller connected to the LF motor 513 rotates to convey the recording medium 105. The CR (carriage) motor drive circuit 514 drives the CR (carriage) motor 515 to scan the carriage 101 via the carriage belt 103.

[0031] The data sent from the I / F circuit 510 includes not only the data to be recorded but also the data of the settings configured by the printer driver. Also, the data to be recorded may be stored in a storage unit such as the RAM 503 after being received from the outside via the I / F circuit 510, or may be stored in advance in a storage unit such as a hard disk. The CPU 501 reads the image data from the storage unit and controls the image processing circuit 509 to execute conversion (binarization processing) into recording data for using the recording head 102. The image processing circuit 509 executes various image processes such as color space conversion, HV conversion, gamma correction, and rotation of the image, in addition to the binarization processing.

[0032] The fan drive circuit 516 controls the air volume from the fan by controlling the rotation speed of the blower fan 402. The heater drive circuit 517 controls the temperature of the heater 403 based on the heating temperature setting information from the CPU 501 and the temperature feedback from the temperature sensor 404 provided closest to the heater 403. The timer 518 measures the heating time by the fixing device.

[0033] <Flowchart at the time of automatic fixing condition setting> Figure 6(a) is a flowchart of the process for automatically setting the fixing conditions. The process in Figure 6(a) is executed when the user adds the type of recording medium to be used in the recording apparatus 100. In S601, the user sets the recording medium 105. The recording apparatus 100 includes a set unit (mounting unit) (not shown) for setting the recording medium 105, and when the recording medium 105 is set in the set unit, it is detected by a detection means (not shown) that the setting state is established. In S602, the user inputs the setting of the number of print passes when performing recording on the recording medium 105 via the input / output unit 109, and the heat-resistant temperature of the set recording medium 105. Here, the number of print passes may be automatically set when the user selects the print mode, or may be input by the user each time. In S603, the CPU 501 adjusts the setting of the optical sensor 201 based on the information input in S602. The flow of S603 will be described later.

[0034] In S604, the heater 403 and the blower fan 402 are driven to heat the inside of the fixing device 108. Here, the heating temperature inside the fixing device 108 is the minimum temperature at which the ink used in the present embodiment is fixed to the recording medium 105, and is about 70°C. When the temperature inside the fixing device 108 stabilizes at the aforementioned minimum temperature, the process proceeds to S605, and the ejection of ink from the recording head 102 to the recording medium 105 is started, and a patch for detecting the fixing state is printed. Here, the recording head 102 prints a patch with the driving amount at the maximum print duty that can be printed.

[0035] When the patch printing is completed in S605, the process proceeds to S606, and the optical sensor 201 measures the intensity of the reflected light on the patch. Here, light is irradiated from the LED 301 at an angle of 60° in the Z direction, and the normal reflection component that receives the reflected light from the printed patch on the recording medium 105 at an angle of 60° in the Z direction is detected. In S607, it is determined whether the total heating time obtained by adding a certain time to the cumulative heating time of the recording medium 105 in the range where the patch printing is performed exceeds the maximum fixing time. The cumulative heating time will be described later.

[0036] If the result in S607 is YES, that is, if the total heating time is less than the maximum fixing time, the recording medium is conveyed to the fixing device 108 and heated for a certain time in S608. The fixed heating time is determined by how much resolution the time change of the normal reflected light intensity is measured. The maximum fixing time is determined in advance from the throughput obtained from the print path and the conveyance direction distance of the fixing device, and is the time when the ink can be dried during normal printing. For example, if the linear speed in the set print path is 4.3 mm / sec and the conveyance direction distance of the fixing device 108 is 400 mm, the maximum fixing time is 93 sec.

[0037] In S609, the cumulative heating time is memorized. Then, in S610, the recording medium 105 is rewound and conveyed so that the patch position returns to the position of the optical sensor 201. In S611, the specularly reflected light is measured again by the optical sensor 201 and stored in the EEPROM 504. Based on this measurement of the specularly reflected light, it is determined in S612 whether the printed patch is fixed, and the flow from S607 to S612 is repeated until it is determined that the patch is in the fixed state. When it is determined in S612 that YES, that is, the patch is in the fixed state, the process proceeds to S613, and the fixing temperature and the cumulative heating time required for fixing are stored in the EEPROM 504 as the fixing conditions.

[0038] When it is determined in S607 that the total heating time is equal to or longer than the maximum fixing time (S607: NO), the process proceeds to S614. In S614, the heating temperature setting of the fixing device 108 is increased by 5°C. In S615, the set value of the increased heating temperature is compared with the heat resistance temperature of the medium, and if the set value of the heating temperature is lower than the heat resistance temperature of the medium (S615: YES), the process returns to S605. If the set value of the heating temperature is equal to or higher than the heat resistance temperature of the medium in S615 (S615: NO), the process proceeds to S616 to reduce the throughput.

[0039] The flowchart of the specific process of S616 is shown in Fig. 6(b). The process of Fig. 6(b) obtains the time required to fix the ink to the recording medium 105 at the highest temperature within the range not exceeding the heat resistance temperature of the recording medium 105.

[0040] When the process proceeds to S616 in Fig. 6(a), the process starts from S617. In S617, the addition of the heating temperature performed in S614 is canceled, and the heating temperature is returned to the temperature before addition. In S618, the optical sensor 201 measures the reflected light intensity on the patch. In S619, it is determined whether the cumulative heating time exceeds twice the maximum fixing time. If it is twice or more (S619: NO), the process proceeds to S627, and it is determined that the recording medium is one for which automatic fixing condition setting cannot be performed (error). At this time, an error notification may be given to the user via the input / output unit 109, and the notification method may be sound, light, vibration, or a combination thereof. Also, the determination criterion of twice the maximum fixing time is only a guideline, and it may be appropriately changed according to the deformation characteristics of the recording medium 105, the printing mode, etc., or a time exceeding twice the maximum fixing time may be used as the determination reference time.

[0041] In S619, if it is determined that the cumulative heating time is less than twice the maximum fixing time (S619: YES), the recording medium is conveyed to the fixing device 108 and heated for a certain time in S620. The constant heating time here is synonymous with that in step S608 in Fig. 6(a).

[0042] In S621, the cumulative time of the heating time is stored. Then, in S622, the recording medium 105 is rewound and conveyed so that the patch position returns to the position of the optical sensor 201. In S623, the regular reflected light is measured again by the optical sensor 201 and stored in the EEPROM 504. It is determined whether the printed patch is fixed in S612 by this regular reflected light measurement (S624). If it is not determined to be in the fixed state, the process returns to S619.

[0043] When it is determined in S624 that the printed patch is fixed (S624: YES), the additional time required to be added to the maximum fixing time is calculated (S625). Then, it is decided whether to change to the number of printing passes corresponding to the required additional time or to provide a scan interval wait during printing, and the information is stored in the EEPROM 504 as the fixing condition (S626).

[0044] In the specific process of S616 described in FIG. 6(b), the fixing time is calculated with the heating temperature set to be lower than the heat resistance temperature of the medium. This is to take into account damage such as expansion and contraction of the recording medium due to heat. Also, since the process of increasing the heating temperature by the fixing device 108 is not performed, power consumption can be suppressed compared to the case where the processes from S607 to S612 are repeated in the flow of FIG. 6(a).

[0045] <Sensor setting flow> In the sensor setting of S603 in FIG. 6(a), when measuring the intensity of the specularly reflected light, the current value flowing into the first LED 301 (hereinafter referred to as the current value) or the amplified value of the current generated by the first photodiode 304 receiving light (hereinafter referred to as the amplified value) is set. By changing the current value, the emission intensity of the LED is changed. Here, both the current value and the amplified value are set, but only one of these parameters may be set. This creates the possibility of automatically setting the fixing conditions even for media for which automatic setting of the fixing conditions was impossible due to circuit structure constraints. Also, mismeasurement of the specularly reflected light intensity due to circuit structure constraints is reduced, and the accuracy of automatic setting of the fixing conditions is improved. In FIG. 6(a), sensor setting is performed in S603, but sensor setting may be performed at any timing. Also, here it is executed as part of the automatic fixing condition setting flow, but the sensor setting is not limited to the example shown here and is applicable when there is a light emitting source or its light receiving source.

[0046] Here, the sensor setting flow of S603 will be described.

[0047] FIG. 7(a) is a flowchart for explaining the process of the sensor setting flow (S603 in FIG. 6(a)). When the sensor setting flow is started, first, the fixing device 108 is heated to a predetermined temperature (S701). The predetermined temperature is ideally a temperature that does not damage the medium and efficiently fixes the applied ink. Here, it is set to the heat resistance temperature of the medium set in S602.

[0048] When the temperature of the fixing device 108 reaches a predetermined temperature, a fixing patch is printed on the medium in S702. Here, the flow is such that the fixing patch is printed after the fixing device reaches the predetermined temperature. However, it suffices if the predetermined temperature is reached before the fixing patch reaches the fixing device. Also, it is desirable that the amount of driving and the type of ink are such that the difference in the specular reflection light intensity is the largest before and after fixing for the fixing patch.

[0049] Next, in step S703, the fixing patch printed next is conveyed to the fixing device and heated for a predetermined time. Here, it is assumed that the conveyance roller is driven to convey the fixing patch to the fixing device. However, the means for the fixing patch to reach the fixing device is not limited, for example, if the fixing device is movable. Also, the predetermined time is ideally the time when it is assumed that the printed patch is fixed to the medium. For example, it is set to twice the time required to pass through the distance from the upstream end (point A in FIG. 4) to the downstream end (point B in FIG. 4) of the fixing device at the conveyance speed when printing with the set maximum number of passes.

[0050] After heating for the predetermined time, the fixing patch is conveyed to a position where it can be measured by the optical sensor 201 (S704). Here, it is assumed that for each set medium, the conveyance roller conveys the fixing patch directly below the LED 301 mounted on the optical sensor 201. However, the moving means of the fixing patch is not limited.

[0051] In S705, the optical sensor 201 measures the specular reflection light intensity of the fixing patch and adjusts the current value and the amplification value. Here, the current value and the amplification value are determined to meet three conditions. The information on the current value and the amplification value adjusted to meet each condition is stored in the EEPROM 504. Also, the value after digital conversion of the specular reflection light intensity of the fixing patch under each condition measured during the adjustment process is also stored in the EEPROM 504.

[0052] In S706, a patch is printed again on the medium 2 (referred to as an unfixed patch). The patch to be printed here is printed at a location different from the patch printed in S702. The ink used for printing the unfixed patch is the same type of ink (with similar ink composition components) as that used for printing the fixed patch. The ink injection amount is also set under the same conditions as when creating the fixed patch, and a patch similar to the fixed patch immediately after printing is printed.

[0053] In S707, the current values and amplification values of the LED 301 and the fat diode 304 are set to the respective conditions adjusted in S705, the specular reflection light intensity of the unfixed patch is measured, and the digitally converted values are stored in the EEPROM 504. For example, let the combinations of the three conditions of the current value and the amplification value adjusted in S705 be set A, set B, and set C. For example, when measuring under the conditions of set A, the current value and the amplification degree are set to set A → the specular reflection light intensity of the unfixed patch is measured → the measured value is stored in the EEPROM 504, and the same applies when measuring under the conditions of set B and set C. It is desirable that the distance between the gloss sensor 201 and the medium to be printed during the specular reflection light intensity measurement and the angle of the gloss sensor with respect to the medium are the same as those during the specular reflection light intensity measurement of the fixed patch.

[0054] When S707 ends, the EEPROM 504 is referred to after S708, and the specular reflection light intensities obtained by measuring the fixed patch and the unfixed patch are compared by the determination unit 522. Here, an example of the comparison flow is shown. Let the order of the conditions under which the output value of the specular reflection light intensity converted by the A / D conversion circuit increases be set A > set B > set C. Also, assume that the current values and amplification values stored in the EEPROM define the specular reflection light intensity output values of the fixed patch and the unfixed patch measured at each set as shown in Fig. 7(b).

[0055] In S708, A f and A nf are compared. A f and A nf The difference between (A f - A nf) is R or more (S708: YES), the process proceeds to S709 where the current value and the amplification value are set to the values of set A, and the current value and the amplification value of set A remain in the EEPROM 504. R is a value that can be determined to have a change in the intensity of specularly reflected light in the fixed state detection even for an unknown medium.

[0056] In S708, if A f and A nf the difference is less than R (S708: NO), the process proceeds to S710 where the absolute value of the difference between B f and B nf (|B f -B nf |) and the absolute value of the difference between C f and C nf (|C f -C nf |) are compared. If |B f -B nf | is greater than or equal to |C f -C nf | (S710: YES), the process proceeds to S711 where the current value and the amplification value are set to the values of set B, and the current value and the amplification value of set B remain in the EEPROM 504.

[0057] In S710, if |B f -B nf | is less than |C f -C nf | (S710: NO), the process proceeds to S712 where the current value and the amplification value are set to the values of set C, and the current value and the amplification value of set C remain in the EEPROM 504.

[0058] <Sensor setting value determination flow> The S705 shown in Fig. 7(a), that is, the sensor setting value determination flow, will be described with reference to Fig. 8(a).

[0059] In the sensor setting value determination flow, the setting values of the current value and the amplification value that satisfy three conditions are determined for the specular reflection light intensity output value of the fixing patch converted by the A / D conversion circuit. Here, it is assumed that there are upper and lower limit values for the output value of the A / D conversion circuit due to the constraints of the optical sensor and the A / D conversion circuit. In this case, three conditions are set for the digital output value range of the specular reflection light intensity obtained from the fixing patch, which is converted by the A / D conversion circuit, and they are set as set A, set B, and set C respectively (shown in Fig. 8(b)). Set A is set as the upper numerical range for the digital output value range of the specular reflection light intensity, set B is the middle numerical range, and set C is the lower numerical range. The current value and the amplification value when these conditions are satisfied are determined. By setting the current value and the amplification value to any of these according to the digital output value result of the specular reflection light intensity of the unfixed patch, the accuracy of the fixing state detection is improved.

[0060] For example, consider the case where the upper limit value of the digital output value range of the specular reflection light intensity is 1000, the lower limit value is 0, and the resolution is 1, and the measurable range is expressed as 0 - 1000. At this time, for example, 800 - 900 is condition A, 450 - 550 is condition B, and 100 - 200 is condition C. It is assumed that by excluding 10% from the upper and lower limits as a margin and adjusting the current value and the amplification value within 10% of the measurable range, it is possible for the digital output value of the specular reflection light intensity to satisfy each condition. These numerical values and ranges are just examples and need to be appropriately determined according to the optical sensor and the configuration related to the specular reflection light measurement. The current value and the amplification value when the digital output value of the specular reflection light intensity satisfies condition A are set as set A, the current value and the amplification value when it satisfies condition B are set as set B, and the current value and the amplification value when it satisfies condition C are set as set C.

[0061] Here, the current value and the amplification value are adjusted in the order of Set A → Set B → Set C, but these orders are not limited (S801, S802, S803). In S804, the current value and the amplification value are adjusted so that the digital output value of the specular reflection light intensity satisfies Condition A. In S805, the current value and the amplification value are adjusted so that the digital output value of the specular reflection light intensity satisfies Condition B. In S806, the current value and the amplification value are adjusted so that the digital output value of the specular reflection light intensity satisfies Condition C. The adjustment method of the current value and the amplification value is described in the sub-flow (sensor adjustment flow).

[0062] <Sensor adjustment flow> S804, S805, and S806 shown in FIG. 8(a) will be described. The sensor adjustment flow for adjusting the current value and the amplification value will be described with reference to FIG. 9(a). In the sensor adjustment flow, the current value and the amplification value are adjusted so that the specular reflection light intensity of the fixing patch satisfies each condition, and the adjusted current value and amplification value are stored.

[0063] In S901, the specular reflection light intensity of the fixing patch after heating for a predetermined time is measured, and the specular reflection light intensity output value converted by the A / D conversion circuit, and the current value and the amplification value at this time are stored in the RAM503.

[0064] In S902, the addition unit adds 1 to N, which represents the number of times the specular reflection light intensity has been measured in this flow. The initial setting value of N is 0.

[0065] In S903, the determination unit 522 compares N with a predetermined number of times. When N becomes a value larger than the predetermined number of times (S903: NO), the process proceeds to S917, and it is determined that the adjustment of the current value and the amplification value is impossible, and the sensor setting flow is terminated. Here, the predetermined number of times is set to 10, and when N≧11 is satisfied, it is determined that the adjustment of the current value and the amplification value is impossible.

[0066] If N is less than or equal to a predetermined number of times at S903 (S903: YES), the process proceeds to S904, where the determination unit 522 refers to the RAM 503 and determines whether the measured regular reflection light intensity satisfies the target conditions (904). For example, when shifting from S804 to the sensor adjustment flow, it is determined whether the digital output value of the measured regular reflection light intensity satisfies condition A (here, the digital output value of the regular reflection light intensity is in the range of 800 - 900). If the conditions are satisfied, the current value, amplification value, and the acquired regular reflection light intensity are stored in the EEPROM 504, and the process proceeds to the sensor setting value determination flow. If the conditions are not satisfied, the process proceeds to S905.

[0067] At S905, the determination unit 522 determines whether the digital output value of the regular reflection light intensity acquired at S901 satisfies the target conditions. If the value is greater than the target condition range, the process proceeds to S906; if the value is smaller, the process proceeds to S912.

[0068] At S906, it is determined whether the output of the LED 301 has reached the upper limit, that is, whether the current value that can flow into the LED 301 has reached the upper limit. If the current value has not reached the upper limit, the current value is increased and the process proceeds to S901 (S907). For example, when the upper limit of the current value that can flow through the LED is set to 30 (setting 6) and the lower limit is set to 5 (setting 1) as shown in Fig. 8(c), six setting values are prepared in increments of 5. If the initial value is 15 (setting 3), when the current value needs to be increased, it is set to the next value, 20 (setting 4). If the current value has reached the upper limit (setting 6), the process proceeds to S910.

[0069] At S910, it is determined whether the amplification value of the output amplification circuit 520 has reached the upper limit. If the amplification value has not reached the upper limit, the amplification value is increased and the process proceeds to S901 (S911). For example, when the upper limit of the output amplification circuit is set to 250 (setting 6) and the lower limit is set to 0 (setting 1) as shown in Fig. 8(d), six setting values are prepared in increments of 50. If the initial value is 100 (setting 3), when the amplification value needs to be increased, it is set to the next value, 150 (setting 4). If the amplification value has reached the upper limit (setting 6), the adjustment of the current value and the amplification degree becomes impossible, and the sensor setting flow ends.

[0070] In S912, it is determined whether the output of the LED 301 has reached the lower limit, that is, whether the current value that can flow into the LED 301 is minimized. If the current value has not reached the lower limit, the current value is decreased and the process proceeds to S901 (S913). For example, when the initial value is 15 (setting 3) as shown in Fig. 8(c), if it is desired to decrease the current value, it is set to 10 (setting 2), which is the value one step lower. When the current value has reached the lower limit (setting 1), the process proceeds to S915.

[0071] In S915, it is determined whether the amplification value of the output amplifier circuit 520 has reached the upper limit. If the amplification value has not reached the lower limit, the amplification value is decreased and the process proceeds to S901. For example, when the initial value is 100 (setting 3) as shown in Fig. 8(d), if it is desired to decrease the amplification value, it is set to 50 (setting 2), which is the value one step lower. When the amplification value has reached the lower limit (setting 1), adjustment of the current value and the amplification value becomes impossible and the sensor setting flow ends.

[0072] As described above, in the sensor adjustment flow, the current value and the amplification value are determined so as to satisfy each condition.

Explanation of Signs

[0073] 100 Recording device 105 Recording medium 108 Fixing device 109 Input / output unit 201 Optical sensor 501 CPU 504 EEPROM

Claims

1. A recording head that discharges a liquid onto a recording medium to form an image; A fixing means that heats the liquid discharged by the recording head to fix the image onto the recording medium; A reflected light measuring means having a light emitting part and a light receiving part capable of measuring the intensity of the reflected light of the image; A control means for setting the light emission intensity of the light emitting part and the amplification degree of the light receiving part of the reflected light measuring means; and The control means sets the light emission intensity or the amplification degree of the reflected light measuring means based on a first reflected light intensity measured by the reflected light measuring means with respect to the image fixed by the fixing means and a second reflected light intensity measured by the reflected light measuring means with respect to the image before being fixed by the fixing means. A recording apparatus characterized by the above.

2. The recording head is mounted on a carriage, discharges a liquid onto the recording medium while moving together with the carriage, and the reflected light measuring means is mounted on the carriage. The recording apparatus according to claim 1, characterized in that.

3. The setting of the light emission intensity and the amplification degree when the reflected light measuring means measures the second reflected light intensity is the same as the setting of the light emission intensity and the amplification degree when measuring the first reflected light intensity. The recording apparatus according to claim 1, characterized by the above.

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