JP5772104B2 - Inkjet recording apparatus, recording medium floating detection method, recording medium floating detection program, and recording medium - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, a recording medium floating detection method, a recording medium floating detection program, and a recording medium, and more specifically, an ink jet recording apparatus that detects the floating of a recording medium as an image recording target with high accuracy. The present invention relates to a recording medium floating detection method, a recording medium floating detection program, and a recording medium.

  As an image forming apparatus that prints and outputs an image on paper based on image data, it is high speed, low noise, few restrictions on the type of recording medium, and easy colorization. (Hereinafter, referred to as an inkjet recording apparatus as appropriate) has become widespread.

  An ink jet recording apparatus discharges ink droplets from nozzles and moves an image onto a recording medium while relatively moving a recording head equipped with fine nozzles for discharging minute ink droplets and a recording medium such as paper. Form. The ink droplets ejected from the nozzle land on the recording medium to form an image.

  However, in an inkjet recording apparatus, ink is ejected from the nozzles of the recording head and an image is formed on the recording medium conveyed by the conveyor belt. In order to improve the landing performance on the recording medium, the distance between the nozzle and the recording medium is set to be small, and when the recording medium is lifted from the conveyance belt, the recording medium collides with the recording head, There is a problem that clogging occurs or ink attached to the recording head adheres to the recording medium and image quality deteriorates.

  In view of this, a technique has been proposed in which lifting of a sheet transported on the transport path is detected, and when the sheet is lifted, the sheet is separated from the transport path for transporting to the image recording unit and retracted (Patent Document 1). reference). In other words, this conventional technique tries to prevent the paper from colliding with the recording head and causing the paper jam or the paper to become dirty due to the paper floating.

  However, in the above prior art, it is trying to prevent the paper jam and the paper from becoming dirty by detecting the paper lift, but it does not show how to detect the paper lift. There is a demand for a technique for accurately detecting the paper lift and appropriately preventing nozzle clogging and paper contamination.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording apparatus that detects a floating of a recording medium with high accuracy, a recording medium floating detection method, a recording medium floating detection program, and a recording medium.

In order to achieve the above object, the present invention reciprocates in a main scanning direction a carriage on which a recording head having nozzles for ejecting ink to a recording medium is moved, so that the recording medium is perpendicular to the main scanning direction. The surface of the recording medium that is transported in the scanning direction, sent to the ink ejection position from the nozzle of the carriage, and attached to a moving body that reciprocates in the main scanning direction is transported to the ink ejection position. It is characterized in that the presence or absence of floating of at least the end of the recording medium is determined based on a change pattern of the differential signal output by differentiating the detection signal detected and output by the detection means.

  According to the present invention, the floating of the recording medium can be detected with high accuracy.

1 is a schematic configuration diagram of a main part of an ink jet recording apparatus to which an embodiment of the present invention is applied. FIG. 2 is a plan view of a main part of the ink jet recording apparatus. FIG. 3 is a diagram illustrating an example of a nozzle surface of a recording head. FIG. 6 is a diagram illustrating an example of a state in which a sheet floating detection sensor is attached to a carriage. FIG. 6 is a diagram illustrating another example of attachment of a sheet floating detection sensor to a carriage. 1 is a block configuration diagram of an ink jet recording apparatus. FIG. 3 is a block diagram of a carriage operation control system based on detection of sheet floating. 6 is a flowchart showing basic image recording processing. 9 is a flowchart showing sheet floating detection processing. Explanatory drawing of the movement direction with respect to a paper floating detection sensor, and the presence or absence state of a paper floating. FIG. 11 is a diagram illustrating a floating detection signal output from a paper floating detection sensor corresponding to FIGS. FIG. 11 is a diagram illustrating a floating detection signal output from a paper floating detection sensor corresponding to FIGS. 10 (c) and 10 (d). The figure which shows the moving direction of the carriage corresponding to the A direction and B direction of FIG. The figure which shows the example in case the paper is floating. The figure which shows an example of the signal waveform of a floating detection signal and a differential signal when there is no floating. The figure which shows an example of the signal waveform of a float detection signal and differential signal when there exists a float. 9 is a flowchart illustrating a paper floating detection process in consideration of a pattern change threshold. The figure which shows the relationship between the peak value of a float detection, and a threshold value. 6 is a flowchart illustrating a paper floating detection process in consideration of a peak value of a floating detection signal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The range of this invention is unduly limited by the following description. However, not all the configurations described in the present embodiment are essential constituent elements of the present invention.

  1 to 19 are diagrams showing an embodiment of an ink jet recording apparatus, a recording medium floating detection method, a recording medium floating detection program, and a recording medium according to the present invention. FIG. 1 is a schematic configuration diagram of a main part of an ink jet recording apparatus 1 to which an embodiment of a recording apparatus, a recording medium floating detection method, a recording medium floating detection program, and a recording medium are applied.

  In FIG. 1, the inkjet recording apparatus 1 includes a paper feeding unit 2, an image recording unit 3, and the like. The paper feeding unit 2 records a roll paper (recording medium) P having a predetermined width by a conveyance roller 21. The roll paper P is cut by the cutter 22 according to the length of the image formed by the image recording unit 3 while being conveyed to the unit 3.

  The image recording unit 3 is provided with a carriage 32 movably attached to a guide rod 31 that is stretched over a length exceeding a predetermined sheet width in the main scanning direction (the vertical direction in FIG. 1). As shown in FIG. 2, recording heads 33a to 33d of a predetermined plurality of colors (for example, cyan (C), magenta (M), yellow (Y), black (K)) are arranged in the main scanning direction (FIG. 2). (In the X direction). The image recording unit 3 is provided below the carriage 32 with a flat platen 34 that supports a roll paper (hereinafter simply referred to as “paper”) P that is fed from the paper feeding unit 2 and conveyed. An air suction portion 35 is disposed below the platen 34, and an air hole (not shown) is formed in the platen 34. In the image recording unit 3, the air suction unit 35 sucks air through the air holes of the platen 34, so that the paper P sent from the paper feeding unit 2 is brought into close contact with the platen 34 without being bent (see FIG. 2 in the Y direction).

  The image recording unit 3 is provided with a conveyance roller 36 on the downstream side in the conveyance direction of the paper P. The conveyance roller 21 of the paper feeding unit 2 and the conveyance roller 36 of the image recording unit 3 are rotated by a paper feed motor 37. Driven to transport the paper P.

  Further, the carriage 32 of the image recording unit 3 is moved in the main scanning direction along the guide rod 31 by a driving mechanism (not shown) being driven by a carriage motor 38.

  The motor control unit 39 is controlled by a paper feed motor 37 and a carriage motor 38 to control the conveyance of the paper P and the movement of the carriage 32.

  As shown in FIG. 3, the recording heads 33a to 33d have a plurality of nozzles n1 to n20 in FIG. 3 formed on the surface of the paper P, that is, the platen 34, and the nozzle n1. ˜n20 are formed in two rows, a nozzle row nr1 composed of n1, n3,..., N19 and a nozzle row nr2 composed of nozzles n2, n4,. The nozzle row nr1 and the nozzle row nr2 can discharge ink of the same color or different colors, respectively, and by discharging ink from the nozzle rows nr1 and nr2 of the recording heads 33a to 33d to the paper P, the paper P An image is formed on.

  In addition, the recording heads 33a to 33d have one side of the main scanning direction X of the carriage (moving body) 32 as shown in FIG. 4B with respect to the normal carriage 32 shown in FIG. A sheet floating detection sensor (recording medium detecting means) 40 is attached to the surface of FIG. 4. In the case of FIG. 4B, the sheet floating detection sensor 40 has a plurality of reflective photosensors arranged in the sub-scanning direction Y. Thus, the detection direction is attached to the sheet P, that is, the direction perpendicular to the surface of the platen 34, and the floating detection signal is output by detecting the floating of the sheet P. The sheet floating detection sensor 40 is mounted at a predetermined sensor height h from the mounting surface L of the carriage 32 and at a predetermined sensor height h from the upper surface of the platen 34. When the paper 40 detects the floating of the sheet P while the carriage 32 is moving, the motor control unit 39 stops the rotation of the carriage motor 38 in response to a carriage stop command to the motor control unit 39, and the carriage 32 is quickly stopped. Thus, the braking distance can prevent the sheet P floating and the recording heads 33a to 33d mounted on the carriage 32 from coming into contact with each other. This braking distance can be obtained by the following equation (1).

Braking distance = [initial speed (m / s)] 2 ÷ 2 gμ (1)
Here, g is a gravitational acceleration, and μ is a coefficient of friction between the carriage 32 and the guide rail 31.

  As can be seen from the above formula (1), the slower the initial speed is, the smaller the braking distance is. Therefore, the lower the moving speed of the carriage 32 until the end of the paper P is detected, the longer the attachment distance L is. The sheet floating detection sensor 40 can be directly attached to the carriage 32 with the attachment distance L set to “0”.

  Note that the sheet floating detection sensor 40 is not limited to the mounting direction in the direction orthogonal to the surface of the sheet P as described above. For example, as shown in FIG. The sheet floating detection sensor 40 may be attached to the carriage 32 in an inclined state so as to detect the front in the direction X. In this case, by setting the mounting angle of the sheet floating detection sensor 40 to the carriage 32 to be an inclination in consideration of the braking distance, the sheet P is moved to the carriage 32 when the sheet P is detected while the carriage 32 is moving. Can be prevented from coming into contact with the recording heads 33a to 33d. In this case, the mounting height h of the sheet floating detection sensor 40 to the carriage 32 is within a range of distance that can be measured by the sheet floating detection sensor 40 regardless of the mounting angle of the sheet floating detection sensor 40. In addition, the height is such that it does not contact the paper P reliably. Regarding the distance in this case, when a reflection type photosensor is used as the paper floating detection sensor 40, there is a range in which the measurement distance and the output signal do not have a linear relationship depending on the sensor. Therefore, an output signal in a linear range is obtained. Set to a distance that you can.

  The sheet floating detection sensor 40 has a length in the sub-scanning direction that can measure all the ends of the normal sheet P, or a plurality of sensor elements arranged side by side. However, as shown in FIG. 5B, as the paper floating detection sensor 40, a small sensor is used as the paper floating detection sensor 40, and only the floating of the corner (corner) of the paper P is used. May be detected.

  The main part of the inkjet recording apparatus 1 is configured as a block as shown in FIG. 6 and includes a CPU (Central Processing Unit) 50, an image processing unit 60, an image recording unit 70, and the like. Although not shown, an operation display unit, a network I / F (interface), and the like are provided. The operation display unit includes various keys necessary for operating the inkjet recording apparatus 1, and includes a lamp such as a display (for example, a liquid crystal display) or an LED (Light Emitting Diode). The operation display unit performs various operations such as various operations necessary for image recording processing (printing processing) using the ink jet recording apparatus 1 and various setting values for detecting paper floating as will be described later from the operation keys. The contents of the command input from the operation keys and various information notified from the inkjet recording apparatus 1 to the operator are displayed on the display.

  A CPU (floating discriminating means, discriminating means) 50 controls each part of the ink jet recording apparatus 1 based on a program in a ROM (not shown) to execute basic processing as the ink jet recording apparatus 1 and to detect paper float described later. The image recording control process accompanying the process and the sheet floating is executed.

  That is, the inkjet recording apparatus 1 includes a ROM, an EEPROM (Electrically Erasable and Programmable Read Only Memory), an EPROM, a flash memory, a flexible disk, a CD-ROM (Compact Disc Read Only Memory), a CD-RW (Compact Disc Rewritable), a DVD. (Floating detection method for recording member) according to the present invention recorded on a computer-readable recording medium such as (Digital Versatile Disk), SD (Secure Digital) card, MO (Magneto-Optical Disc), etc. ) And a sheet floating detection program (recording member floating detection program) and an image recording control program for executing the image recording control method are read and introduced into a ROM or a hard disk (not shown) to accurately lift the sheet P described later. Detection, and image recording is controlled based on the floating detection result of the paper P. It is constructed as an ink jet recording apparatus that executes a paper floating detection method and an image recording control method to be controlled. The sheet floating detection program and the image recording control program are computer-executable programs written in a legacy programming language such as an assembler, C, C ++, C #, Java (registered trademark), an object-oriented programming language, or the like. It can be stored and distributed in the recording medium.

  The image processing unit 60 includes a RAM (Random Access Memory) 61, an image processing unit 62, an image data conversion unit 63, an ink non-ejection area detection unit 64, an interface 65, a droplet number measurement unit 66, an ejection nozzle determination unit 67, and the like. The image recording unit 70 includes a RAM 71, the motor control unit 39, a paper feed motor 37, a carriage motor 38, an interface 72, a recording head control unit 73, a recording head unit 74, and the like.

  In the image processing unit 60, the RAM 61 stores multi-value image data to be image-recorded, and the image processor 62 corresponds the multi-value image data in the RAM 61 to the nozzles n1 to n20 of the recording heads 33a to 33d. Conversion to small value data (the number of gradations equal to the type of droplet to be ejected).

  The interface 65 exchanges data and signals between the CPU 50 and the interface 72 of the image recording unit 70, and the image data conversion unit 63 performs one time according to the print mode given from the CPU 50 via the interface 65. The image data is converted into image units to be output in the head scanning (one scan) and recorded again in the RAM 61.

  The ink non-ejection area detection unit 64 stores droplet (ink droplet) -free data in all areas in the main scanning direction on the front end side and the rear end side in the sub-scanning direction in the image data converted into image units for one scan. The number of nozzles n1 to n20 necessary for image recording is determined based on the detection result.

  The discharge nozzle determining unit 67 determines nozzles (groups) n1 to n20 used for recording image data for one scan, and the conveyance amount of paper P (paper) for recording with the determined nozzles n1 to n20. (Feed amount) is notified to the CPU 50.

  The image data conversion unit 63 performs image conversion processing again on the converted image data for one scan according to the sub-scanning head positions of the nozzles n1 to n20 to be used.

  The droplet number measuring unit 66 measures the ink discharge amount (droplet number) of each of the nozzles n1 to n20 that discharges ink droplets based on the image data converted into one scan, and records the accumulated amount.

  The image recording unit 70 receives image data from the image processing unit 60 via the interface 72 and stores it on the RAM 71.

  The motor control unit 39 controls the paper feed motor 37 in accordance with the paper feed amount notified from the CPU 50 and transports the paper P in the sub-scanning direction.

  The recording head control unit 73 transfers the image data stored on the RAM 71 to the recording head unit 74 and controls the driving of the nozzles n1 to n20 formed in the recording heads 33a to 33d of the recording head unit 74. .

  The motor control unit 39 controls the carriage motor 38 in synchronization with the transfer of the image data from the recording head control unit 73 to the recording head unit 74, and moves the carriage 32 having the recording heads 33a to 33d in the main scanning direction X. Move.

  The recording head unit 74 ejects ink droplets onto the paper P from the nozzles n1 to n20 of the recording heads 33a to 33d in accordance with the image data transferred from the recording head control unit 73, thereby forming an image record.

  Then, as shown in FIG. 7, the sheet floating detection sensor 40 attached to the carriage 32 outputs a floating detection signal to the I / O unit 80, and the I / O unit 80 includes the differentiation circuit 81 and the I / O unit. An O ASIC (Application Specific Integrated Circuit) 82 and the like are provided.

  The I / O unit 80 branches and inputs the floating detection signal from the paper floating detection sensor 40 to the differentiation circuit 81 and the I / O ASIC 82. Both of these floating detection signals are A / D (analog / Digital conversion) is input to the port and digitally converted. The differentiation circuit (differentiation means) 81 performs a differentiation process on the digitally converted floating detection signal from the paper floating detection sensor 40 and outputs a differential signal to the I / O ASIC 82.

  The I / O ASIC 82 is connected to the CPU 50 through a local bus, and the CPU 50 detects the floating detection signal from the I / O ASIC 82 paper floating detection sensor 40 and the differential floating detection signal obtained by performing the differential processing of the differential circuit 81 (hereinafter referred to as appropriate). It is simply referred to as a differential signal), and it is determined from the read signal whether the paper P is floating or not. The CPU 50 starts printing when the paper P is not floating. If the CPU 50 determines that the paper P is floating, the CPU 50 outputs a carriage stop signal to the motor control unit 39 via the I / O ASIC 80, and the motor control unit 39 stops driving the carriage motor 38. Thus, the movement of the carriage 32 is stopped.

  Next, the operation of this embodiment will be described. The true ink jet recording apparatus 1 accurately detects the floating of the paper P by the paper floating detection sensor 40 and controls the image recording operation according to the floating of the paper P.

  First, an image recording operation process for one page by the inkjet recording apparatus 1 will be described with reference to FIG.

  The CPU 50 sets the recording size for one page in the image processing unit 60 from the print settings (step S101), and similarly sets a print mode that is a set group including the number of prints, the number of print colors, the resolution, and the like. (Step S102).

  In the image processing unit 60, when the print size and the print mode are set, the image processing unit 62 performs image processing on the print data to multi-value image data, stores the data in the RAM 61, and further stores the data in the RAM 61. The multi-value image data is converted into small value data corresponding to the nozzles n1 to n20 of the recording heads 33a to 33d (the number of gradations equal to the type of droplet to be ejected) (step S103).

  The image processing unit 62 performs pre-image data conversion processing on the small value image data in the RAM 61 for each image to be recorded in the next one scan (step S104), and the ink non-ejection area detection unit 64 performs the next time. Of the image data converted into one scan, an area in which all the areas in the main scanning direction on the front end side and the rear end side in the sub-scanning direction are no-drop (no ink enemy) data is detected, and the number of used nozzles n is determined. (Step S105).

  When the number of used nozzles n is determined, the discharge nozzle determining unit 67 selects the nozzles n1 to n20 to be used for ink discharge in the next one scan, and sends the paper feed amount corresponding to the selected nozzles n1 to n20 to the CPU 50. Notification is made (step S106).

  In the image processing unit 60, the image data conversion unit 63 again performs image conversion processing (post-image conversion) on the converted image data for one scan in accordance with the sub-scanning head positions of the nozzles n1 to n20 to be used. Process) (step S107), and the droplet number measurement unit 66 measures the ink ejection amount (number of droplets) of each of the nozzles n1 to n20 that ejects ink droplets based on the image data converted into one scan. Then, integrated recording is performed (step S108).

  When the image recording unit 70 receives the image data from the image processing unit 60 via the interface 72 and stores it on the RAM 71, the motor control unit 39 makes a paper feed motor according to the paper feed amount notified from the CPU 50. 37 is controlled to transport the paper P in the sub-scanning direction (step S109).

  In the image processing unit 60, the recording head control unit 73 transfers the image data stored on the RAM 71 to the recording head unit 74, and drives the nozzles n1 to n20 of the recording heads 33a to 33d of the recording head unit 74. Under control, the motor control unit 39 controls the carriage motor 38 in synchronization with the transfer of the image data from the recording head control unit 73 to the recording head unit 74, and the carriage 32 having the recording heads 33a to 33d is controlled. Move in the main scanning direction X (step S110).

  When printing for one scan is completed, the image processing unit 60 checks whether printing for the recording size set by the CPU 50 is completed (step S111). If printing for the recording size is not completed, step S103 is performed. Returning to step S103, the image processing is performed in the same manner as described above (steps S103 to S111).

  In step S111, the inkjet recording apparatus 1 ends the image recording operation process when printing for the recording size is completed.

  In the image recording operation process, the inkjet recording apparatus 1 performs a paper floating detection process as shown in FIG. 9 and controls the image recording operation according to whether or not the paper P is lifted.

  That is, when the CPU 50 starts moving the carriage 32 by the image recording unit 70 (step S201), the floating detection signal output from the paper floating detection sensor 40 is digitally converted by the I / O ASIC 82 of the I / O unit 80. The detection signal and the differential signal that has been differentially converted by the differential circuit 81 and digitally converted are taken in to check whether the differential signal has changed (step S202).

  When there is a change in the differential signal, the CPU 50 reads the change pattern of the differential signal, that is, whether the change is from minus to plus or from plus to minus (step S203). It is determined whether or not it is similar to a floating change pattern registered in advance in a nonvolatile memory (floating change pattern storage means) or the like (step S204).

  If the change pattern of the differential signal is not similar to the floating change pattern in step S204, the CPU 50 determines that no floating has occurred on the paper P and starts image recording (printing) (step S205).

  When the differential signal change pattern is similar to the floating change pattern in step S204, the CPU 50 determines that the paper P is floating and starts image recording (printing) (step S206).

  That is, for example, as shown in FIGS. 10A and 10B, when the paper floating detection sensor 40 is fixed and the paper P is moved in the A direction, as shown in FIG. In the case where there is no floating, the floating detection signal from the paper floating detection sensor 40 is detected as shown in FIG. 11A from the state where the output level is low and the detection state of the platen 34 (hereinafter simply referred to as platen). When the signal level rises to a signal level corresponding to the paper thickness and becomes constant after the signal level has been lowered to the signal level of the detection state.), As shown in FIG. As shown in FIG. 11 (b), the floating detection signal from the paper floating detection sensor 40 rises once according to the floating of the paper P from the state where the low output level of the paper is not detected. The signal level corresponding to the A certain Te. 10 (a) and 10 (b), the same paper P is used. Therefore, in any of the floating detection signals in FIGS. 11 (a) and 11 (b), the signal level once stabilized is the same. The signal level is the same because it is the paper P, but the slope of the waveform when changing from the signal level in the paper undetected state and the peak value that finally arrives are not the same as when the paper P is floating. It differs greatly from case to case.

  Further, for example, when the paper P moves in the B direction as shown in FIGS. 10C and 10D and the paper P does not float as shown in FIG. As shown in FIG. 12A, the floating detection signal from the floating detection sensor 40 is output after the signal value is once lowered from a state where the signal value is constant at a predetermined signal level corresponding to the sheet thickness. When the signal level is lowered to a low paper undetected signal level and is constant, as shown in FIG. 10D, the floating detection signal from the paper floating detection sensor 40 is as shown in FIG. As shown in (b), after the signal value rises once according to the floating of the paper P from the state where the signal value is constant at a signal level of a predetermined height corresponding to the paper thickness, Decreases to the signal level of the detection state and becomes constant. Also in this case, since the same paper P is used in both FIGS. 10 (c) and 10 (d), once the floating detection signals in FIGS. 12 (a) and 12 (b) are once stabilized. The signal level is the same because the paper P is the same, but the signal level is the same, but the slope of the waveform when changing from the signal level that has not been detected and the peak value that is finally reached are when the paper P is floating It differs greatly from the case of not floating.

  Then, the ink jet recording apparatus 1 when the paper P of FIGS. 10A and 10B is moved in the A direction and when the paper P of FIGS. 10C and 10D is moved in the B direction. The movement of the carriage 32 corresponds to FIGS. 13 (a) and 13 (b).

  Further, as the case where the paper P is floating, for example, as shown in FIG. 14A, when only the corner of the paper P is floating, as shown in FIG. 14B, the paper P In some cases, the end in the main scanning direction floats over the entire sub-scanning direction.

  In other words, the floating detection signal of the paper floating detection sensor 40 and the signal waveform of the differential signal obtained by differentiating the floating detection signal by the differentiation circuit 81 are from before the detection of the paper P in the main scanning direction of the paper P until after the detection ends. When the paper P is not lifted, the paper P is shown as shown in FIGS. 15A and 15B. When the paper P is lifted, the paper P is lifted as shown in FIGS. 16A and 16B. Shown in

  That is, when the sheet P is not lifted, as shown in FIG. 15, the lift detection signal is generated after the signal level is lowered from the sheet undetected state to the state when the platen is detected. When the signal level continues to a constant value corresponding to the sheet width, the signal level decreases to the signal level of the platen detection value, and then reaches the signal level in the sheet undetected state. At this time, the differential signal obtained by differentiating the floating detection signal by the differentiating circuit 81 becomes a signal value of a negative predetermined level because the floating detection signal decreases from the signal level when the sheet is not detected to the signal level when the platen is detected. Since the floating detection signal increases from the signal level in the platen detection state to the signal level in the sheet thickness detection state, the signal value is switched to a positive positive signal value. After that, the differential signal remains unchanged by the flat sheet width, and then the floating detection signal drops from the sheet thickness signal level to the signal level at the time of platen detection. After that, since the floating detection signal rises from the signal level at the time of detecting the platen to the signal level in the sheet non-detection state, the signal value is switched to a positive predetermined level. That is, the differential signal has a change pattern that changes from minus to plus at the end portion of the sheet P as shown in FIG. 15 when the sheet P does not float.

  Further, when there is a float at both ends in the main scanning direction of the paper P, as shown in FIG. 16, the float detection signal is a signal from a signal level in the paper non-detected state to a paper float level corresponding to the float amount of the paper P. After the level is increased, the signal level decreases to a signal level corresponding to the thickness of the paper P (paper thickness), and when a constant value continues for the flat paper width, the paper floating amount level corresponding to the floating amount of the paper P is reached. After the signal level is increased, the signal level is decreased to the signal level in the paper non-detected state. At this time, the differential signal becomes a positive positive signal value because the floating detection signal rises from the paper non-detected state level to the paper floating amount level, and then the floating detection signal is changed from the paper floating amount level to the paper thickness. Since the signal level decreases to a signal level, the signal value is switched to a negative negative signal value. After that, the differential signal continues to be constant for a flat sheet width, and then the float detection signal rises from the sheet thickness signal level to the sheet lift amount level. Since the floating detection signal decreases from the paper floating amount level to the paper non-detected state level, the signal value is switched to a negative predetermined level. That is, the differential signal has a change pattern that changes from plus to minus at the end of the paper P as shown in FIG.

  Then, the inkjet recording apparatus 1 registers the change pattern of the differential signal in advance in a non-volatile memory such as a ROM (Read Only Memory) in accordance with the state information of whether or not the paper P is lifted, and the paper P This is used to determine the presence or absence of the float. In the ink jet recording apparatus 1 of the present embodiment, only the change pattern (the pattern in which the differential signal changes from plus to minus) when there is floating is registered in the nonvolatile memory.

  In the paper floating detection process of FIG. 9, the CPU 50 reads the change pattern of the differential signal (step S203) and determines whether it is similar to the change pattern with paper floating registered in the nonvolatile memory in advance. (Step S204).

  Therefore, it is possible to easily and appropriately detect whether or not the paper P is lifted.

  The differential signal change pattern is used to determine whether to stop driving the carriage 32 and stop image recording based on the change pattern. The presence / absence of floating may be determined in consideration of the above detection error and the floating amount of the paper P that is a floating amount that causes a problem in image recording.

  Therefore, as shown in FIG. 17, the inkjet recording apparatus 1 registers a change amount of a differential signal for determining whether or not the paper P is lifted in advance in a nonvolatile memory as a threshold change amount, and the detected change pattern of the differential signal is It may be determined that the sheet P is floating when the variation pattern is when there is floating and the variation amount of the variation pattern is equal to or greater than the threshold variation amount. In FIG. 17, the same processing steps as those in FIG. 9 are given the same step numbers to simplify the description.

  That is, as shown in FIG. 17, when the CPU 50 starts moving the carriage 32 by the image recording unit 70 (step S201), the CPU 50 outputs the floating detection signal output from the paper floating detection sensor 40 to the I / O unit 80. The floating detection signal digitally converted by the O ASIC 82 and the differential signal digitally converted by the differential circuit 81 are taken in, and it is checked whether the differential signal has changed (step S202).

  When there is a change in the differential signal, the CPU 50 reads the change pattern of the differential signal (step S203), and determines whether the change pattern is similar to a floating change pattern registered in advance in a nonvolatile memory or the like (step S204). .

  If the change pattern of the differential signal is not similar to the floating change pattern in step S204, the CPU 50 determines that no floating has occurred on the paper P and starts image recording (printing) (step S205).

  When the change pattern of the differential signal is similar to the floating change pattern in step S204, the CPU 50 reads the threshold change amount of the nonvolatile memory, and the change amount of the change pattern is equal to or greater than the threshold change amount. (Step S301), and if the change amount of the change pattern is less than the threshold change amount, it is determined that the paper P is not lifted or is in a range where there is no problem even if it occurs. Image recording (printing) is started (step S205).

  If the change amount of the change pattern is greater than or equal to the threshold change amount in step S301, the CPU 50 determines that the paper P is floating to some extent of trouble, and starts image recording (printing) (step S206).

  Therefore, the presence or absence of floating is determined in consideration of the unevenness of the paper P itself, noise, the detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording. Thus, the floating of the paper P can be detected with higher accuracy and appropriateness.

  Further, the floating detection signal output from the floating sheet detection sensor 40 is used to determine whether to stop driving the carriage 32 and stop image recording based on the peak value of the floating detection signal itself. The presence / absence of floating may be determined in consideration of the unevenness, noise, detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording.

  Therefore, as shown in FIG. 18, the inkjet recording apparatus 1 needs to determine that the unevenness of the paper P itself, noise, detection error of the paper floating detection sensor 40, and the amount of floating of the paper P are such that image recording troubles occur. An allowable peak threshold is set in consideration of whether or not there is a certain amount of floating, and the like is stored in the non-volatile memory, and as shown in FIG. 19, the CPU 50 peaks the floating detection signal output from the paper floating detection sensor 40. The value is compared with an allowable peak threshold value, and it is determined whether or not the sheet P is floated and image recording is hindered. In FIG. 19, the same processing steps as those in FIG. 9 are given the same step numbers, and the description thereof will be simplified.

  That is, as shown in FIG. 19, when the CPU 50 starts to move the carriage 32 by the image recording unit 70 (step S201), the CPU 50 outputs the floating detection signal output from the paper floating detection sensor 40 to the I / O unit 80. The floating detection signal digitally converted by the O ASIC 82 and the differential signal digitally converted by the differential circuit 81 are taken in, and it is checked whether the differential signal has changed (step S202).

  When there is a change in the differential signal, the CPU 50 reads the change pattern of the differential signal (step S203), and determines whether the change pattern is similar to a floating change pattern registered in advance in a nonvolatile memory or the like (step S204). .

  If the change pattern of the differential signal is not similar to the floating change pattern in step S204, the CPU 50 determines that no floating has occurred on the paper P and starts image recording (printing) (step S205).

  In step S204, when the change pattern of the differential signal is similar to the floating change pattern, the CPU 50 reads the allowable peak threshold value of the nonvolatile memory and detects the floating detection output from the non-differentiated paper floating detection sensor 40. It is checked whether the peak value of the signal is equal to or greater than the allowable peak threshold value (step S401). If the peak value of the floating detection signal is less than the allowable peak threshold value, the paper P is not lifted or has been generated. However, it is determined that there is no problem, and image recording (printing) is started (step S205).

  If the peak value of the floating detection signal is greater than or equal to the allowable peak threshold value in step S401, the CPU 50 determines that the paper P is floating to some extent of trouble, and starts image recording (printing) (step S206).

  In the above description, the peak value of the floating detection signal is compared with the allowable peak threshold value to determine whether the paper P is floating, but the positive peak value of the differential signal is compared with a predetermined allowable peak threshold value. Thus, the presence or absence of the sheet P may be determined.

  Therefore, the presence or absence of floating is determined in consideration of the unevenness of the paper P itself, noise, the detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording. Thus, the floating of the paper P can be detected with higher accuracy and appropriateness.

  In the description of FIGS. 9 and 17, whether or not the sheet P is lifted based on the differential signal change pattern obtained by differentiating the detection signal from the paper floating detection sensor 40 by the differentiation circuit 81 and the change amount of the differential signal. However, the presence or absence of the sheet P may be determined based on the change pattern of the floating detection signal itself output from the paper floating detection sensor 40 or the amount of change in the floating detection signal.

  As described above, the ink jet recording apparatus 1 according to the present embodiment reciprocates the carriage 32 in which the recording heads 33a to 33d having the nozzles n1 to n20 for ejecting ink onto the paper (recording medium) P are reciprocated in the main scanning direction. The paper P is transported in the sub-scanning direction orthogonal to the main scanning direction, sent to the ink discharge positions from the nozzles n1 to n20 of the carriage 32, and attached to a moving body that reciprocates in the main scanning direction. Based on the change pattern of the floating detection signal output by detecting the surface of the conveyed paper P with the paper floating detection sensor 40, it is determined whether or not at least the edge of the paper P is floating.

  Accordingly, it is possible to detect the floating of the paper P, which is a recording medium, with high accuracy, and by controlling the drive of the carriage 32 based on the detection result of the floating of the paper P to control the image recording, the nozzle It is possible to appropriately prevent clogging of n1 to n20 and paper stains.

  Further, in the ink jet recording apparatus 1 of the present embodiment, the paper floating detection sensor 40 outputs a detection signal that increases in the positive direction according to the floating amount of the paper P, and the CPU 50 changes the detection signal from positive to negative. The predetermined change pattern is stored in the nonvolatile memory as a floating change pattern indicating that the paper P is floating, and the change pattern of the floating detection signal output from the paper floating detection sensor 40 is compared with the floating change pattern. If it is, it is determined that the paper P is floating.

  Therefore, the floating of the paper P can be accurately detected based on the change pattern of the detection signal of the paper floating detection sensor 40, and the floating of the paper P can be accurately detected with a simple configuration.

  Furthermore, in the ink jet recording apparatus 1 of the present embodiment, when the CPU 50 detects that the change amount of the detection signal output from the paper floating detection sensor 40 from plus to minus exceeds a preset threshold change amount, It is determined that P is floating.

  Therefore, the presence or absence of floating is determined in consideration of the unevenness of the paper P itself, noise, the detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording. Thus, the floating of the paper P can be detected with higher accuracy and appropriateness.

  Further, in the ink jet recording apparatus 1 of the present embodiment, the sheet floating detection sensor 40 outputs a detection signal that increases in the positive direction according to the sheet P floating amount, and the sheet floating detection sensor 40 outputs the detection signal. A predetermined change pattern in which the differential signal differentiated by the differentiating circuit 81 changes from plus to minus is stored in the nonvolatile memory as a floating change pattern indicating that the paper P is floating, and the float output from the paper float detection sensor 40 is stored. If the change pattern of the differential signal obtained by differentiating the detection signal by the differentiation circuit 81 is compared with the floating change pattern of the nonvolatile memory, it is determined that the paper P is floating.

  Accordingly, the floating of the paper P can be accurately detected based on the differential signal change pattern obtained by differentiating the detection signal of the paper floating detection sensor 40, and the floating of the paper P can be accurately detected with a simple configuration. it can.

  Further, in the ink jet recording apparatus 1 of the present embodiment, when the change amount from the plus to minus of the differential signal obtained by differentiating the detection signal of the sheet floating detection sensor 40 exceeds a preset threshold value change amount, It is determined that P is floating.

  Therefore, the presence or absence of floating is determined in consideration of the unevenness of the paper P itself, noise, the detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording. Thus, the floating of the paper P can be detected with higher accuracy and appropriateness.

  Further, the ink jet recording apparatus 1 of the present embodiment acquires the peak value of the floating detection signal output from the paper floating detection sensor 40, and if the peak value exceeds a preset threshold peak value, the paper P Is determined to be floating.

  Therefore, the presence or absence of floating is determined in consideration of the unevenness of the paper P itself, noise, the detection error of the paper floating detection sensor 40, and whether the floating amount of the paper P is a floating amount that causes a problem in image recording. Thus, the floating of the paper P can be detected with higher accuracy and appropriateness.

  In the above description, the case where the edge of the paper P is floated in the main scanning direction is described as an example, but the same applies to the case where the paper P is lifted at a place other than the edge of the main scanning direction. Can be applied.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to that described in the above embodiments, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  The present invention can be applied to an inkjet recording apparatus that detects floating of paper P and appropriately records an image, a recording medium floating detection method, a recording medium floating detection program, and a recording medium.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Paper feed part 3 Image recording part P Roll paper (paper)
DESCRIPTION OF SYMBOLS 21 Conveyance roller 22 Cutter 31 Guide rod 32 Carriage 33a-33d Recording head 34 Platen 35 Air suction part 36 Conveyance roller 37 Paper feed motor 38 Carriage motor 39 Motor control part n1-n20 Nozzle nr1, nr2 Nozzle row 40 Paper floating detection sensor 50 CPU
60 Image processing unit 61 RAM
62 Image processing unit 63 Image data conversion unit 64 Ink ejection failure area detection unit 65 Interface 66 Drop number measurement unit 67 Discharge nozzle determination unit 70 Image recording unit 71 RAM
72 Interface 73 Recording Head Control Unit 74 Recording Head Unit 80 I / O Unit 81 Differentiation Circuit 82 I / O ASIC

JP 2010-131859 A

Claims (8)

A carriage on which a recording head having a nozzle for discharging ink onto a recording medium is mounted;
Moving means for reciprocating the carriage in the main scanning direction;
A recording medium conveying means for conveying the recording medium in a sub-scanning direction orthogonal to the main scanning direction and sending the recording medium to an ink ejection position from the nozzle of the carriage;
A recording medium detection unit that is attached to a moving body that reciprocates in the main scanning direction, detects a surface of the recording medium that is transported to the ink ejection position, and outputs a detection signal;
Differentiating means for differentiating the detection signal from the recording medium detection means and outputting a differential signal;
A float discriminating means for discriminating whether or not the recording medium floats based on a change pattern of the differential signal output from the differential means;
An ink jet recording apparatus comprising: The recording medium detection means includes
Output a detection signal that increases in the positive direction according to the floating amount of the recording medium,
The float determining means includes
Floating change pattern storage means for storing a predetermined change pattern in which the differential signal changes from positive to negative as a floating change pattern indicating that the recording medium is floating;
If the change pattern of the differential signal obtained by differentiating the detection signal output from the recording medium detection means by the differentiation means is similar to the floating change pattern, it is determined that the recording medium is floating. Discrimination means;
The inkjet recording apparatus according to claim 1, further comprising: The recording medium detection means includes
Output a detection signal that increases in the positive direction according to the floating amount of the recording medium,
The float determining means includes
The amount of change from the positive to the negative differential signal, when it exceeds a threshold variation which is preset, an ink jet recording according to claim 1, wherein said determining that the recording medium is lifted apparatus. The recording medium detection means, the movable body is the carriage, claim 1, characterized in that attached to the carriage in a state of detecting the surface of the moving forward of the recording medium of the carriage The ink jet recording apparatus according to claim 3 . The recording medium detection means includes
The ink-jet recording apparatus according to any one of claims 4 to the photosensor der Rukoto claim 1, wherein.   A movement processing step of reciprocally moving a carriage mounted with a recording head having a nozzle for discharging ink onto a recording medium in the main scanning direction;
  A recording medium conveyance processing step of conveying the recording medium in a sub-scanning direction orthogonal to the main scanning direction and sending the recording medium to an ink ejection position from the nozzle of the carriage;
  A recording medium detection processing step that is attached to a moving body that reciprocates in the main scanning direction and detects a surface of the recording medium conveyed to the ink ejection position and outputs a detection signal;
  Differential processing step of differentiating the detection signal and outputting a differential signal;
  A float determination processing step for determining whether or not the recording medium floats based on a change pattern of the differential signal output in the differential processing step;
A floating detection method for a recording medium, comprising:   On the computer,
  A movement process for reciprocating a carriage mounting a recording head having a nozzle for discharging ink onto a recording medium in the main scanning direction;
  A recording medium conveying process for conveying the recording medium in a sub-scanning direction orthogonal to the main scanning direction and sending the recording medium to an ink ejection position from the nozzle of the carriage;
  A recording medium detection process that is attached to a moving body that reciprocates in the main scanning direction and detects the surface of the recording medium conveyed to the ink ejection position and outputs a detection signal;
  Differential processing for differentiating the detection signal and outputting a differential signal;
  A float determination process for determining whether or not the recording medium floats based on a change pattern of the differential signal output in the differential process;
A program for detecting floating of a recording medium, characterized in that   A computer-readable recording medium on which the recording member floating detection program according to claim 7 is recorded.

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