JP5808572B2 - Recording device - Google Patents

Description

The present invention relates to a recording equipment for performing printing while scanning the print head in the direction perpendicular to the conveying direction of the recording medium. It relates specifically to the recording equipment for the detection of an edge of the recording medium.

  2. Description of the Related Art Conventionally, there is known an ink jet printer that performs printing while intermittently feeding a recording sheet, which is a recording medium, in a vertical direction and scanning a printing head in a horizontal direction.

  In this printer, in order to detect the lateral width of the recording paper or to detect the lateral displacement (skew) of the recording paper, the lateral edges of the recording paper set on the platen, that is, the left and right edges are detected. An edge detection device for detection is provided.

  Further, the edge position of the recording paper is detected before printing, and the drawing start point is kept at a certain distance from the end of the recording paper.

  In addition, during printing operations, edges are detected at regular intervals to monitor whether there is any horizontal misalignment (skew), and if a skew occurs, the operation panel will ask the user whether to interrupt the printing operation. I am trying to select it above.

Here, a conventional edge detection apparatus will be briefly described.
In the edge detection device, an edge detection photosensor such as a reflective photomicrosensor is provided on the carriage so as to face the platen.

  The edge detection device scans the carriage laterally so that the photosensor crosses the edge of the recording paper in a state of facing the recording paper set on the platen, and the reflected light amount of the recording paper and the recording paper are separated from the recording paper. The point at which the sensor output of the photosensor has changed below a predetermined threshold due to the difference from the amount of reflected light on the non-reflective tape on the platen at the position has been detected as the edge of the recording paper.

  Specifically, the CPU in the edge detection device acquires the sensor output of the photosensor at a predetermined cycle (for example, 10 ms cycle), compares the sensor output with a predetermined threshold value, and detects the edge of the recording paper. Was.

  In addition, Japanese Patent Application Laid-Open No. 2007-210747 discloses that a step response from a photosensor when crossing an edge of a recording sheet is AC-coupled into a differential waveform so that edge detection is possible even during printing, and is amplified and filtered by an operational amplifier. After that, it has been proposed to detect the differential waveform with a comparator.

JP 2007-210747 A

  However, in the conventional method, since the sensor output of the photosensor is acquired at a predetermined cycle (for example, a cycle of 10 ms), the distance that the photosensor moves during the predetermined cycle increases as the carriage moving speed increases. Therefore, as the carriage moving speed increases, the edge detection accuracy decreases.

  For this reason, when a conventional printer with an edge detection device detects the edge of a recording sheet, the carriage movement speed is made slower than the movement speed during printing to maintain the accuracy of edge detection. Therefore, edge detection cannot be performed while moving the carriage at high speed during printing, and throughput and check frequency are reduced.

  In addition, since the light reception level of the reflected light on the non-reflective tape on the platen and the light reception level of the reflected light on the recording paper are compared with the threshold value based on the light reception level itself, if the difference between these light reception levels is small ( For example, when the recording paper is tracing paper), the difference between the received light level and the threshold value becomes small, and the edge of the recording paper cannot be detected accurately.

  In addition, there is a variation in sensitivity in the sensor itself. If the light emission current and the light reception sensitivity of the sensor are made variable to absorb this, it takes time to select them.

  In addition, when performing a construction called tiling where a plurality of printed products are stuck side by side, skew and recording paper expansion and contraction during long-time printing (the recording paper expands by being heated by various heaters, If the recording in the roll state is unwound in the first place, the plotting area for the recording paper width will also shift with the plotting start point between the printed products, causing the image to be misaligned. Will occur.

  In addition, when the print head is displaced in the recording paper feed direction, which is called staggered arrangement, the recording paper is stretched by the drawing by the preceding print head, and the landing position is set in the drawing by the subsequent print head. It may shift. As a result, the landing position is shifted between the colors, resulting in poor image quality.

  In addition, when monitoring the skew at a fixed period, the recording paper may greatly skew between the monitoring at one time and the monitoring at the next time, and the drawing area may be shifted. It is desirable to do.

  When the skew is detected by the skew monitoring, the user must always monitor the printer operation if the user selects whether to interrupt the printing operation on the operation panel. I cannot drive at night.

In order to achieve the above object, the recording apparatus of the present invention includes a recording medium conveying unit that conveys a recording medium, a print head that ejects ink to the recording medium, and the recording medium in its own detection area. A sensor that outputs a first level signal and outputs a second level signal different from the first level when the recording area is not present in the detection area; and the detection area of the sensor defines an edge of the recording medium. A transport unit that transports the sensor so as to cross, an output generation unit that outputs a change detection signal obtained by amplifying the signal through a band-pass filter when the level of the signal output from the sensor changes, and the output generation The change of the change detection signal output from the recording unit is based on the result of comparison with the respective threshold voltages when the recording medium is moved from a position where there is no recording medium to a position where the recording medium is present and where it is moved from a position where there is no recording medium. An edge detection control unit that detects an edge of the recording medium, a position detection unit that detects a linear scale disposed along a moving direction of the transport unit, and detects the position of the sensor; and the edge detection control A memory for extracting and storing a position detected by the position detecting means when the edge of the recording medium is detected by the unit, and an amount of change in the width of the recording medium based on the position stored in the memory And a drawing area calculation unit for calculating a drawing area on the recording medium based on the width, and the print head and the recording medium conveying means based on the change amount with respect to the calculated drawing area. And a print control unit that controls the transport unit to perform a printing operation, the transport unit is equipped with the print head, and the print control unit is configured to control the linear scale by the position detection unit. The position of the transport unit is calculated based on the output, the ink ejection timing of the print head is calculated based on the position, and the recording medium is transported by the recording medium transport means when the recording medium is transported. Without detecting the edge of the medium and recording by the print head, the conveyance unit is moved when the conveyance of the recording medium is stopped to detect the edge of the recording medium and by the print head. When recording is performed and the edge is detected, the width of the recording medium, the change amount of the width, and the drawing area are calculated, and recording on the recording medium by the print head is performed when the recording medium is initially printed Based on the amount of change in the width of the latest recording medium with respect to the width of the image, and the increase / decrease in the dots of the line to be recorded based on the latest drawing area, the latest drawing area is calculated. In the recording apparatus in which an image is recorded in the area, the first print head and the first print head are disposed at positions shifted downstream of the first print head in the transport direction of the recording medium. At least a second print head that ejects the ink of a color different from the color of the ink of the print head, and the sensor detects the edge of the recording medium corresponding to a position where the first print head prints At least a second sensor for detecting the edge of the recording medium corresponding to a position where the second print head prints, and the print control unit includes: The printing operation is performed by controlling the first print head based on the drawing area calculated based on the output and the amount of change, and the calculation calculated based on the output of the second sensor. Based on the image area and the amount of change, the second print head is controlled to perform the printing operation, and in response to a change in the width of the recording medium due to expansion and contraction occurring between the first sensor and the second sensor. Thus, the maximum number of dots that can be ejected to the same line by the first print head and the second print head varies .

  Further, the drawing area calculation unit of the recording apparatus of the present invention may include a drawing area calculation unit that calculates the drawing area so as to maintain a certain distance from the edge of the recording medium.

  Further, the drawing area calculation unit of the recording apparatus of the present invention may include a drawing area calculation unit that calculates the drawing area so as to maintain a certain range in the left-right direction of the recording medium based on the recording medium width. it can.

  In addition, the printing control unit of the recording apparatus according to the present invention may increase by overlapping a predetermined dot on the drawing area when the drawing area calculated by the drawing area calculation unit is changed from an initial state. The printing control unit can perform a printing operation for changing the drawing area width of the recording medium by reducing the number by thinning.

  In addition, since the edge detection according to the present invention simultaneously detects edges at different points in the conveyance direction of the recording medium, a plurality of the sensors can be installed at locations where the edges at the different points can be detected.

According to the above invention, the edge of the recording medium is detected based on the change detection signal.
The change detection signal is output when the level of the signal output from the sensor changes. Therefore, even if the sensor output signal level difference between when the sensor detects the recording medium and when the sensor does not detect it is small, the change detection signal is output when the sensor detects the edge of the recording medium. Therefore, it is possible to detect an edge of a recording medium that could not be detected because the level difference between the output signals of the sensors is small.

  The output signal level of the sensor changes when the detection area of the sensor crosses the edge of the recording medium, and the rate of change in the level increases as the crossing speed increases. For this reason, even if the detection area of the sensor crosses the edge of the recording medium, the edge of the recording medium can be detected, and the speed of edge detection can be increased.

  According to the above invention, the edge of the recording medium can be detected at high speed and with high accuracy during the printing operation, and thereby printing can be accurately performed at a predetermined position on the recording medium.

  According to the present invention, since the edge of the recording medium is detected based on the change detection signal output when the level of the signal output from the sensor changes, the level difference between the sensor output signals is detected. It becomes possible to detect the edge of the recording medium that could not be done, and even if the detection area of the sensor increases the speed of crossing the edge of the recording medium, it does not depend on the surface state of the recording medium, and unexpected disturbance light etc. The edge of the recording medium can be detected without being affected by the above. Further, by calculating the drawing area from the left and right edges of the recording medium detected during printing as needed, even if there is a skew or expansion / contraction of the recording medium, roll-like recording medium winding deviation, etc., a predetermined area of the recording medium Thus, it becomes possible to improve the printing accuracy.

FIG. 1 is a block diagram showing a main configuration of a printer apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating an example of a paper transport mechanism of the printer apparatus. FIG. 3 is a block diagram illustrating an example of an edge detection mechanism of the printer apparatus. FIG. 4 is an explanatory diagram for explaining an example of setting the signal pass band of the band pass filter. FIG. 5 is a diagram showing the edge position of the sheet at the beginning of printing. FIG. 6 is a diagram showing the edge position of the paper when it is shifted due to skew or the like. FIG. 7 is a diagram showing the edge position of the paper when the expansion and contraction and the like match. FIG. 8 is a diagram showing dots in the drawing area when the paper is not expanded or contracted. FIG. 9 is a diagram showing that the drawing is performed by adding dots in the drawing area when the sheet is stretched. FIG. 10 is a diagram illustrating drawing by thinning dots in the drawing area when the paper shrinks. FIG. 11 is a flowchart for explaining the operation of the recording apparatus. FIG. 12 is a schematic diagram of a carriage when the print head is staggered.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a main configuration of a printer apparatus according to an embodiment of the present invention.
In FIG. 1, a printer apparatus 1 intermittently feeds large-size paper (recording medium) such as A1 size, A0 size, and large-size roll paper in the vertical direction, and laterally moves a print head 60 that ejects ink in dots. This is an inkjet printer for large format paper that performs printing while scanning in the direction.

  The printer apparatus 1 includes a CPU 10, a paper feed motor driver 20, a paper feed motor 21, a carriage control motor driver 30, a carriage control motor 31, an edge sensor 40, a sensor control circuit 45, a print head 60, A head controller 65.

  The CPU 10 governs overall control of the printer apparatus 1. A program is stored in a memory connected to the CPU 10, and the CPU 10 operates according to the program to control the printer device 1. The paper feed motor 21 is a drive unit for feeding a paper as a recording medium in the vertical direction. The motor driver 20 controls the driving of the motor 21. The print head 60 performs printing by ejecting ink dots. The head controller 65 ejects ink dots from the print head 60. The carriage control motor 31 is an example of a transport unit, and sends the print head 60 and the edge sensor 40 in the horizontal direction. The motor driver 30 controls driving of the carriage control motor 31.

  The edge sensor 40 outputs a first level signal when there is a sheet in its own detection area, and outputs a second level signal different from the first level when there is no sheet in the detection area. The edge sensor 40 is, for example, a photo sensor that detects reflected light from a sheet and reflected light from a non-reflective tape placed in a region on the platen. The sensor control circuit 45 processes a signal output from the edge sensor 40.

  The print control unit 55 stores print data from a host PC (not shown) in the print data storage memory 50, and reads it out as necessary. The read print data is converted into a data string that can be input to the print head 60, processed according to the drawing area calculated based on the edge position detected by the edge sensor control circuit 45, and then transferred to the head controller 65. To do.

  FIG. 2 is a schematic diagram showing the mechanism of the transport system of the print head 60. In FIG. 2, the same components as those shown in FIG.

  In FIG. 2, the print head 60 is attached to a carriage 70 configured to be slidable in the horizontal direction, and the carriage 70 is slid in the horizontal direction to set the platen 53 and the sheet 5 set on the platen 53. The scan is moved in the horizontal direction above the.

  Further, the edge sensor 40 is attached to the side end of the carriage 70 in a state where the detection direction is directed to the platen 53 side, and scans with the print head 60.

  The carriage 70 is fixed to a steel belt 72 of a conveyance belt mechanism 71 that constitutes a conveyance unit, and a drive pulley 73 of the conveyance belt mechanism 71 is rotated by a carriage control motor 31, and then laterally passes through a timing belt 79 and a driven pulley 74. Move to slide.

  Further, the carriage 70 is provided with a linear sensor 75 for detecting the movement amount, and the linear sensor 75 detects a detection groove of the linear scale 76 that is fixedly arranged along the movement direction of the carriage 70. The movement amount of the carriage 70 is detected by counting the detection grooves.

  The detection output (count value) from the linear sensor 75 is input to the motor driver 30 of the carriage control motor 31 and the head control unit 65 of the print head 60, and is used for controlling the movement amount of the carriage 70, or the print head 60. It is used to control the ink ejection timing.

  FIG. 3 is a block diagram illustrating an example of an edge detection mechanism in the printer apparatus 1, specifically, an edge sensor 40, a sensor control circuit 45, and the CPU 10. In FIG. 3, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

  The edge sensor 40 includes a light emitting element 40a and an optical sensor 40b. The sensor control circuit 45 includes a capacitor C1, a resistor R1, an operational amplifier 45a, a capacitor C2, a resistor R2, a comparator 45b, a comparator 45c, and an FPGA (Field Programmable Gate Array) 45d.

  The light emitting element 40 a emits light toward the detection region of the edge sensor 40. The light emitting element 40a is connected in series with the resistor R3. The optical sensor 40b is connected in series with the resistor R4, and receives light reflected by an object in the detection region of the edge sensor 40.

  For this reason, the edge sensor 40 outputs a signal of a level corresponding to the amount of reflected light received by the optical sensor 40b from the terminal A. Specifically, the edge sensor 40 outputs a signal indicating a step response (level is high when there is no paper 5 and level is low when there is paper 5) when its detection area crosses the edge of the paper 5. Output.

  The capacitor C1 obtains an AC component (differential waveform) from this step response. The AC component is generated at the terminal A when the edge sensor 40 crosses the edge of the paper.

  The operational amplifier 45a has an inverting input terminal (− terminal) connected to the terminal A via the capacitor C1 and the resistor R1, a non-inverting input terminal (+ terminal) connected to the reference voltage Vref1, and an output terminal connected to the capacitor C2 and the resistor R2. Are connected to the inverting input terminal via a parallel circuit. The operational amplifier 45a amplifies the AC component extracted by the capacitor C1. The AC component amplified by the operational amplifier 45a is used as a change detection signal.

  The capacitor C1 and the resistor R1 form a high pass filter, and the capacitor C2 and the resistor R2 form a low pass filter. The capacitance of the capacitor C1 is c1, the resistance value of the resistor R1 is r1, the capacitance of the capacitor C2 is c2, and the resistance value of the resistor R2 is r2.

  By matching the pass band (fCL = 1 / 2πc1r1, fCH = 1 / 2πc2r2) of the bandpass filter constituted by this high-pass filter and this low-pass filter with the signal frequency of the differential waveform obtained by the capacitor C1. Unnecessary band components can be removed. The signal frequency of the differential waveform depends on the moving speed of the carriage.

FIG. 4 is an explanatory diagram for explaining an example of setting the passband of the bandpass filter.
As shown in FIG. 4, the passband (fCL to fCH) of the bandpass filter is desirably set according to the slope of the voltage change at the terminal A.

  The comparator 45b compares the output of the output generator 45e, that is, the output of the operational amplifier 45a, with the threshold reference voltage Vref2, and generates a detection output when the output of the operational amplifier 45a is greater than the reference voltage Vref2. The comparator 45c compares the output of the output generator 45e, that is, the output of the operational amplifier 45a, with the threshold reference voltage Vref3, and generates a detection output when the output of the operational amplifier 45a is smaller than the reference voltage Vref3.

  The FPGA 45d is an example of a control unit, and when the comparator 45b and the comparator 45c generate detection outputs, the detection output (count value) of the linear sensor 75 at that moment is stored in the built-in memory in hardware.

  The CPU 10 acquires the edge position of the paper 5 by reading the detection output (count value) of the linear sensor 75 stored in the FPGA 45d.

  As described above, the edge positions of both ends of the paper 5 can be detected with high accuracy every time the carriage 70 during printing is scanned.

Next, a method for calculating the drawing area from the detected edge position will be described.
FIG. 5 shows the edge positions Y1 and Y2 of the paper 5 at the start of printing, both of which are detected by the above-described means by the edge sensor 40. FIG.

  The original paper width YW1 = Y2−Y1, and the drawing area is added with the width of the drawing area width DW1 from D1 positioned inside the paper 5 by a predetermined offset amount ΔD0 from the edge position Y1 at one end. Up to D2.

  The original paper width YW1 = Y2−Y1, and the drawing area is determined by the image to be drawn from D1 positioned inside the paper 5 by a predetermined offset amount ΔD0 from the edge position Y1 at one end. Up to D2 obtained by adding DW1, that is, DW1 = D2-D1.

  The original paper width YW1 = Y2-Y1, and the drawing area is determined by the image to be drawn from D1 positioned inside the paper 5 by a predetermined offset amount ΔD0 from the edge position Y1 at one end. Up to D2 obtained by adding DW1, that is, DW1 = D2−D1.

  If the paper 5 is displaced due to skew or the like as shown in FIG. 6 during printing, if the edge positions are detected as Y3 and Y4, the paper width YW2 = Y4−Y3 at this time is the same as YW1 at the beginning of printing. If they are equal, there is no expansion / contraction of the paper 50, and it is merely shifted in the main scanning direction due to the skew. Therefore, the drawing area offset from the drawing area at the start of printing by the amount of deviation of the Y5-Y1 paper 5 is set. If a new setting is made, the drawing area at the beginning of printing on the paper 5 is maintained.

  Specifically, the new drawing area is in the range of D3 = D1 + (Y3-Y1), D4 = D2 + (Y3-Y1), and naturally D4-D3 = DW1 = DW2.

  As described above, when the paper width YW1 at the beginning of printing is maintained, the effect of skew or the like can be eliminated by simply applying the initial offset amount ΔD0 to the detected edge position. .

Next, a method for calculating a drawing area when the paper 5 is stretched or contracted will be described.
If the sheet 5 is stretched or contracted, as shown in FIG. 7, the detected edge positions Y5 and Y6 may be shifted in the opposite direction to Y1 and Y2 at the beginning of printing. The detected paper width YW3 = Y6-Y5 does not match YW1.

  Here, the expansion / contraction coefficient α is α = YW3 / YW1, and from these, the offset amount ΔD3 = ΔDxα from the paper edge position, the drawing area width DW3 = DW1xα, and the drawing area edge are D5 = Y5 + ΔD3, D6 = By calculating D5 + DW3, it is possible to maintain the drawing area within a certain range of the paper 5.

  Here, there is a problem of how to apply pixel data given with the same width to the drawing area expanded or contracted due to expansion or contraction of the paper 5, but the method shown in FIGS. 8 to 10 can be considered as an example.

  Although FIG. 8 is a fairly extreme example, it is assumed that dots are ejected on one line in the main scanning direction, and the drawing area width DW1 is 10 based on the number of dots. In order to distinguish the dots in the figure, numbers 1 to 10 are assigned for convenience.

  If the drawing area width DW3 becomes 11 when the paper 5 is stretched, the drawing area width becomes 11 if a specific dot is ejected in duplicate. In FIG. 9A, the dot at the position 5 is overlapped. However, if the nozzles at the position 5 are overlapped in the same manner in the line continuous in the sub-scanning direction, the 5 positions of the completed image are displayed. Since there is a possibility of being visually recognized as a dark line in the sub-scanning direction, it is preferable to disperse the overlapping portions as shown in FIGS. 9B, 9C, and 9D for each line in the sub-scanning direction.

  On the other hand, when the paper 5 is shrunk and the drawing area width DW3 becomes 9, the drawing can be performed by thinning out specific dots. Similarly, the thinned-out portions are shown in FIGS. It is preferable to disperse in the sub-scanning direction as shown in (c) and (d).

  Actually, when drawing at 720 dpi, if a drawing area of 1000 mm extends by 5 mm, 27581 dots are ejected by 142 dots overlapping. In terms of proportion, the concentration increases by 0.5%, but it is very small as a whole.

  It is conceivable that the overlapping or thinned-out dot portions are generated randomly, but in order to deal with the expansion and contraction of the paper 5 almost uniformly in the entire main scanning direction, first, the overlapping of the entire drawing area is performed. Alternatively, a method of arranging dots to be thinned out evenly and shifting the positions on the dots randomly is conceivable.

  For example, in the case of extending 5 mm from the previous 1000 mm, the overlapping 142 dots are temporarily placed at the position where the total drawing length of 27723 dots is divided into 142 (that is, the interval of 195 dots) and generated independently for each. It is conceivable to distribute the random numbers applied.

  Further, when it becomes necessary to overlap an extremely large number of dots, there is a possibility that the density changes as a whole. In this case, it is conceivable that dots are not ejected to the positions of the dots to be ejected in duplicate. Since it is better to eject or not to eject depends on the type of the paper 5, it is preferable that the printer device 1 has as a parameter based on a prior experiment.

  As described above, even if there is a skew or expansion / contraction of the paper, the printing operation can be performed without being influenced as a result.

  FIG. 11 is a flowchart for explaining the operation of the recording apparatus. An operation of printing when the edge of the paper is detected and the paper width is changed will be described with reference to a flowchart.

  The CPU 10 operates according to a program stored in the memory and controls the printer device 1.

  First, an edge of a sheet that is a recording medium is detected (step S1). The paper width is calculated from the detected paper edge, the drawing area is further calculated, and the calculation result is stored in the memory (step S2). Next, from the newly acquired drawing area and the past drawing area, the expansion / contraction information of the drawing area, such as the expansion / contraction rate and the expansion / contraction amount, is calculated, and the result is stored in the memory. (Step S3).

  Next, it is determined whether to add or thin out the dots of the image to be printed from the expansion / contraction information, and it is calculated which dot is to be added or thinned out (step S4). For example, the drawing area is divided according to the amount of expansion / contraction, and dots at random positions in the divided range are added or thinned out. When a random position is specified, a random number is generated and positioning is performed based on the random number.

Information on the recording medium used is stored in advance in the memory. Information on the recording medium is acquired (step S5). From the acquired information of the recording medium and the information of the dot addition or thinning position calculated in step S4, the ejection information relating to the ejection of dots such as thinning out dots, adding dots, and not adding dots is generated (step) S6).
Based on this dot information, the dot overlapping printing and the thinning printing at the position calculated in step 4 are performed (step S7).

  Also, as shown in FIG. 12, when the print head 60 is shifted in the paper feed direction called staggered arrangement, the elongation of the paper 5 generated in a very short time due to the effect of the ink ejected by the preceding print head 60. For this reason, the ejection landing position of the succeeding head may be shifted. However, even in this case, if the extension amount by the preceding print head 60 is detected by the edge sensors 40a and 40b, the printing with the corrected shift is performed. Application to do is possible.

  Specifically, as shown in FIG. 12, on the carriage 70, the edge sensor 40 a located in the vicinity of the preceding print head 60 for M and K colors and the vicinity of the subsequent print head 60 for Y and C colors. This can be realized by using two sensors of the edge sensor 40b located in the position. The edge sensor 40a gives information about the edge of the paper 5 to the control of the print head 60 for M and K colors, and the edge sensor 40b gives the edge information of the paper 5 to the control of the print head 60 for Y and C colors. Give information. For example, as shown in FIG. 12, the edge sensor 40a is disposed at the end of the carriage 70 in the scanning direction at the head of the print head 60 for M and K colors. The edge sensor 40 b is disposed at the end of the carriage 70 in the scanning direction at the head of the Y-color and C-color print heads 60. The edge sensor 40 a can detect the edge of the paper 5 at the head position of the M-color and K-color print heads 60. The edge sensor 40 b can detect the edge of the paper 5 at the head position of the Y-color and C-color print heads 60. Further, in order to detect the edge of the paper 5 at the nozzle position of the print head 60 in each row that prints the same line, for example, the head, the rear end, the center, etc. of each row of the print heads 60 arranged in two rows, It is desirable to detect at the same position.

  First, with respect to the print head 60 for M and K colors that are drawn in advance, the edge sensor 40a is used to draw according to the skew and the expansion and contraction of the paper 5 based on the method described so far. .

On the other hand, when drawing is performed by the Y and C color print heads 60 to be subsequently drawn, as a result of drawing by the preceding print head 60, the sheet 5 may be conveyed in a state of being stretched in the main scanning direction. However, since the change amount due to the expansion and contraction of the paper 50 is detected by the edge sensor 40b, if the drawing is performed according to the change amount, the landing position deviation from the preceding print head 60 can be eliminated as a result.
This is particularly effective for media that tend to expand and contract in a short time due to ink ejection.

DESCRIPTION OF SYMBOLS 1 ... Printer apparatus, 10 ... CPU, 40 ... Edge sensor, 45 ... Sensor control circuit, 45a ... Operational amplifier, 45b ... Comparator, 45c ... Comparator, 45d ... FPGA, 53 ... Platen, 60 ... Print head, 70 ... Carriage, C1 ... Capacitor, C2 ... Capacitor, R1 ... Resistance, R2 ... Resistance

Claims (5)

A recording medium conveying means for conveying the recording medium;
A print head for ejecting ink onto the recording medium;
A sensor that outputs a first level signal when the recording medium is in its own detection area, and that outputs a second level signal different from the first level when there is no recording medium in the detection area;
A transport unit for transporting the sensor such that the detection area of the sensor crosses an edge of the recording medium;
An output generator for outputting a change detection signal obtained by amplifying the signal through a band-pass filter when the level of the signal output from the sensor changes;
Based on the result of comparing the change of the change detection signal output by the output generation unit with the respective threshold voltages when the recording medium is moved from a position where there is no recording medium to a position where the recording medium is moved to a position where there is no recording medium. An edge detection control unit for detecting the edge of the recording medium;
Position detecting means for detecting a linear scale arranged along the moving direction of the transport unit and detecting the position of the sensor;
A memory for extracting and storing a position detected by the position detecting means when the edge of the recording medium is detected by the edge detection control unit;
A drawing area calculation unit that calculates a width of the recording medium and a change amount of the width based on the position stored in the memory, and calculates a drawing area on the recording medium based on the width;
A print control unit for controlling the print head, the recording medium conveyance unit, and the conveyance unit based on the change amount with respect to the calculated drawing area, and performing a printing operation;
Have
The transport unit is equipped with the print head,
The print control unit calculates the position of the transport unit based on the detection of the linear scale by the position detection unit, calculates the ejection timing of the ink of the print head based on the position,
When the recording medium is being conveyed by the recording medium conveying means, the detection of the edge of the recording medium and recording by the print head are not performed, and the conveyance of the recording medium is stopped when the recording medium is stopped. The edge of the recording medium is detected and recording is performed by the print head. When the edge is detected, the width of the recording medium, the amount of change in the width, and the drawing area are calculated. ,
When recording on the recording medium by the print head is performed, the amount of change in the width of the latest recording medium with respect to the width of the recording medium at the beginning of printing and the increase / decrease in the dots of lines to be recorded based on the latest drawing area In a recording device in which an image is recorded and an image is recorded in the latest drawing area ,
The print head has a color different from the color of the ink of the first print head arranged at a position shifted downstream of the first print head and the first print head in the transport direction of the recording medium. At least a second print head for ejecting ink;
The sensor includes a first sensor for detecting the edge of the recording medium corresponding to a position where the first print head prints, and the edge of the recording medium corresponding to a position where the second print head prints. At least a second sensor for detecting
The print control unit performs the printing operation by controlling the first print head based on the drawing area and the amount of change calculated based on the output of the first sensor, and outputs the second sensor. The printing operation is performed by controlling the second print head based on the drawing area and the amount of change calculated based on the recording area, and the recording by the expansion and contraction occurring between the first sensor and the second sensor. The maximum number of dots that can be ejected to the same line by the first print head and the second print head changes according to a change in the width of the medium . The recording apparatus according to claim 1,
The recording apparatus, wherein the drawing area calculation unit calculates the drawing area so as to maintain a certain distance from the edge of the recording medium. The recording apparatus according to claim 1,
The recording apparatus, wherein the drawing area calculation unit calculates the drawing area so as to keep a certain range in the left-right direction of the recording medium based on the recording medium width. The recording apparatus according to any one of claims 1 to 3,
When the drawing area calculated by the drawing area calculation unit is changed from an initial state, the drawing area is increased by overlapping a predetermined dot with the drawing area when the drawing area is expanded. A recording apparatus including the print control unit that performs the printing operation to change the width of the drawing area of the recording medium by reducing a predetermined dot by thinning out the drawing area when the image becomes narrow.   The recording apparatus according to claim 4, wherein the position of the predetermined dot is random.

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