JP2005059451A - Liquid ejector and liquid ejecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the quantity of ink being consumed for printing at an end part sharply. <P>SOLUTION: The liquid ejector comprises a mechanism for carrying a medium in the carrying direction, and a plurality of nozzle groups being arranged along the carrying direction wherein the nozzle group has a plurality of nozzles being arranged along the carrying direction. The liquid ejector performs an operation for ejecting liquid from the nozzle while moving the nozzle group in the direction intersecting the carrying direction, and an operation for carrying the medium by a specified carrying amount with respect to the nozzle group. A plurality of sensors for detecting the end position of the medium in the intersecting direction and outputting end position information are provided in correspondence with the nozzle groups and at least one of liquid ejection start position and liquid ejection stop position is determined for each nozzle group based on the end position information of a sensor corresponding to the nozzle group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid ejection apparatus that ejects liquid droplets toward a medium, and a liquid ejection method.

  A color ink jet printer is well known as an example of a typical liquid ejecting apparatus. This color ink jet printer includes a print head that ejects ink as an example of liquid from nozzles, and is configured to record images, characters, and the like by ejecting ink onto paper as an example of a medium.

  The print head is supported by the carriage with the surface on which the nozzles are formed facing the paper, and moves in a direction perpendicular to the paper transport direction along the guide member (hereinafter also referred to as main scanning). Ink is ejected in synchronization with the main scanning.

  In recent years, color inkjet printers capable of borderless printing have gained popularity. With this borderless printing, for example, it is possible to print by ejecting ink without margins on the four edges of a sheet. (For example, refer to Patent Document 1).

By the way, in the case of borderless printing, since printing is performed on the entire surface of the paper, it is important to prevent a margin from being formed at the edge of the printed paper. In order to achieve this, taking into account that the paper is bent at an angle and fed, print data that is slightly larger than the paper, in other words, with some margin compared to the size of the paper, is used. A method of preparing and printing on paper based on the print data is effective. The margin M required at this time can be calculated by the following equation.
M = H × tan θ
In the above equation, H is the length of the print head in the transport direction, and θ is the inclination angle of the paper with respect to the transport direction.

Further, in order to reduce the problem of the present technique that ink that does not contribute to image formation is consumed when printing is performed on an area other than the sheet by the margin M, the main scanning of the sheet is performed by a sensor. It is also effective to detect the position of the end portion in the direction and change the ink discharge start position or the discharge stop position in accordance with the detected end position.
JP 2002-103586 A (page 10)

  However, if the print head becomes longer or has a plurality of heads, and the substantial length H of the print head becomes longer, the margin M becomes larger from the above equation. In such a case, even if the above-described method for detecting the edge position of the paper is employed, the amount of ink that is discarded into the margin M area inevitably increases, and a large amount of ink may be consumed. There is.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting method capable of greatly reducing the amount of ink consumed for printing on an end portion. It is to be realized.

  A main invention includes a transport mechanism that transports a medium in a transport direction, and a plurality of nozzle groups that are disposed along the transport direction, and the nozzle group includes a plurality of nozzles that are disposed along the transport direction. A discharge operation for discharging liquid from the nozzles while moving the nozzle group in a crossing direction intersecting the transport direction, and a transport operation for transporting a medium by a predetermined transport amount to the nozzle group. A plurality of sensors for detecting the position of the end of the medium in the intersecting direction and outputting the end position information corresponding to each nozzle group. A liquid discharge apparatus characterized in that at least one of a liquid discharge start position and a discharge stop position is determined for each nozzle group based on corresponding end position information of a sensor.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  According to the present invention, it is possible to significantly reduce the amount of ink consumed for printing on the edge.

At least the following matters will be made clear by the description of the detailed description of the invention in this specification.

A transport mechanism for transporting the medium in the transport direction; and a plurality of nozzle groups arranged along the transport direction, each of the nozzle groups having a plurality of nozzles disposed along the transport direction; Liquid that performs a discharge operation for discharging liquid from the nozzles and a transport operation for transporting a medium by a predetermined transport amount to the nozzle groups while moving the nozzle group in a crossing direction that intersects the transporting direction. A discharge device comprising a plurality of sensors for detecting the position of the end of the medium in the intersecting direction and outputting end position information corresponding to each nozzle group, the sensor corresponding to the nozzle group A liquid discharge apparatus that determines at least one of a liquid discharge start position and a discharge stop position for each nozzle group based on end position information.
According to such a liquid ejecting apparatus, each nozzle group includes a dedicated sensor for detecting the end position of the medium. Accordingly, the discharge start position and stop position can be finely adjusted for each nozzle group based on the end position information output from the sensor.

  Here, when the medium is transported while being tilted from the transport direction, the distance from the end of the medium differs for each nozzle group. Even in such a case, each nozzle group has its own sensor. The discharge can be started or stopped individually using the end as a reference. Accordingly, it is possible to greatly reduce the amount of ink consumed for printing on the end portion.

In such a liquid ejecting apparatus, it is desirable that the sensors are arranged closest to the nozzle groups that they are responsible for.
According to such a liquid ejecting apparatus, the sensors are arranged closest to the nozzle groups that they are responsible for. Therefore, the end position information output from each sensor can be optimum information for each nozzle group to start and stop discharging liquid at the end of the medium, and as a result, based on the information, Further, the discharge can be started or stopped with the end portion as a reference.

In such a liquid ejecting apparatus, an inclination angle from the conveyance direction of the medium is calculated based on end position information of at least two sensors having different arrangement positions with respect to the conveyance direction, and the calculated value of the inclination angle is also calculated at the end position. It is desirable to further use as information to determine at least one of a start position and a stop position at which the liquid is discharged.
According to such a liquid ejecting apparatus, since the inclination angle of the medium is also used as the end position information, it is possible to execute the discharge start or the stop with respect to the end more precisely.

In such a liquid discharge apparatus, the discharge start position and the discharge stop position of each nozzle group are changed based on the calculated value M calculated from the inclination angle θ and the length H0 of the nozzle group alone in the transport direction by the following equation. It is desirable to be done.
M = H0 × tanθ
According to such a liquid ejecting apparatus, even when the medium is conveyed while being tilted, the ejection start and the ejection stop can be accurately executed with the end as a reference.

In such a liquid discharge apparatus, it is desirable that the discharge start position and the discharge stop position are set outside the end portion of the medium.
According to such a liquid ejecting apparatus, borderless printing that does not form a margin at the edge of the medium can be performed.

In the liquid ejecting apparatus, the sensor moves in the intersecting direction together with the nozzle group, and the sensor moves in the intersecting direction according to the movement of the light emitting unit in the intersecting direction and the light emitting unit for emitting light. A light receiving portion for receiving the light, and the light emitted by the light emitting portion moving in the intersecting direction is based on a change in an output value of the light receiving portion due to being blocked by the end portion It is desirable to detect the position of the end of the medium.
According to such a liquid ejecting apparatus, the position of the end can be detected more easily.

In such a liquid ejection device, at least one of the liquid ejection start position and the stop position during the current movement operation is determined based on the end position information detected during the previous movement operation of the nozzle group. desirable.
According to such a liquid discharge apparatus, at least one of the discharge start position and the stop position in the current movement operation is determined based on the end position information detected in the previous movement operation. Therefore, even when the end position changes with time, the discharge start position and the stop position can be finely adjusted.

A conveyance mechanism configured to convey the medium in the conveyance direction; and a plurality of nozzle groups arranged along the conveyance direction, each of the nozzle groups having a plurality of nozzles arranged along the conveyance direction. Then, while moving the nozzle group in the intersecting direction intersecting the transport direction, a discharge operation for discharging the liquid from the nozzle and a transport operation for transporting the medium with a predetermined transport amount to the nozzle group are executed. A plurality of sensors for detecting the position of the end of the medium in the intersecting direction and outputting the end position information, corresponding to each nozzle group, Each of them is arranged closest to the nozzle group that it is in charge of, and the sensor moves in the crossing direction together with the nozzle group, and the sensor includes a light emitting unit for emitting light, and the light emitting unit in the crossing direction. Move A light receiving portion for receiving the light that moves in the crossing direction according to the output, and the light emitted by the light emitting portion moving in the crossing direction is blocked by the end portion to output the light receiving portion The position of the end of the medium is detected based on the change in value, and the tilt angle from the transport direction of the medium is calculated based on the end position information of at least two sensors having different arrangement positions with respect to the transport direction. Then, based on the calculated value of the tilt angle and the end position information of the sensor corresponding to the nozzle group, at least one of the liquid discharge start position and the discharge stop position is determined for each nozzle group, and the end of the medium is determined. The discharge start position and the discharge stop position are set on the outside, and based on the end position information detected during the previous movement operation of the nozzle group, the discharge start during the current movement operation A liquid discharge apparatus characterized by determining at least one of the location and the discharge stop position.
According to such a liquid ejecting apparatus, almost all the effects described above can be achieved, and therefore the object of the present invention can be achieved most effectively.

A conveyance mechanism configured to convey the medium in the conveyance direction; and a plurality of nozzle groups arranged along the conveyance direction, each of the nozzle groups having a plurality of nozzles arranged along the conveyance direction. In addition, it is possible to realize a discharge operation for discharging the liquid from the nozzle while moving the nozzle group in a crossing direction intersecting the transport direction, and a liquid discharge method for a medium with a predetermined transport amount with respect to the nozzle group. is there. A liquid ejection method using a liquid ejection apparatus that performs a transport operation for transporting, wherein a sensor that detects the position of an end of the medium in the intersecting direction and outputs end position information is the nozzle group A plurality of the nozzles are used in correspondence with each other, and at least one of the liquid discharge start position and the discharge stop position is determined for each nozzle group based on the end position information of the sensor corresponding to the nozzle group. Schematic configuration example of liquid ejection apparatus ===
FIG. 1 is a perspective view showing an outline of a color inkjet printer (hereinafter referred to as a color printer) 20 as an embodiment of a liquid ejection apparatus.
The color printer 20 is an inkjet printer that can output a color image. For example, cyan (C), light cyan (light cyan, LC), magenta (M), light magenta (light magenta, LM), yellow (Y ), An ink jet printer that prints a printed image by ejecting liquid such as black (K) color ink onto various media such as paper to form dots. The color ink is not limited to the above six colors, and for example, dark yellow (dark yellow, DY) may be used. The color printer 20 is also compatible with relatively large single-sheet paper such as roll paper in which paper is wound in a roll shape as shown in FIG. 1 and JIS standard A-line 0-th paper.
Such a color printer 20 is roughly divided into a printing unit 3 that discharges ink and prints on the roll paper P, and a paper transport unit 5 that transports the roll paper P. Each part will be described below.

――― (1) Printing Department ―――
The printing unit 3 includes a carriage 28 that holds a print head 136, and the carriage 28 is in a direction (hereinafter referred to as a main scanning direction or a horizontal direction) that is substantially orthogonal to the roll paper P conveyance direction (hereinafter also referred to as a sub-scanning direction). A pair of upper and lower guide rails 34 for guiding the carriage 28 so as to be reciprocally movable, a carriage motor 30 for reciprocating the carriage 28, and for transmitting the moving force F of the carriage motor 30 to the carriage 28. Traction belt 32 and a position detection sensor 18 for detecting the current position of the carriage 28 in the main scanning direction.

(1-A) Carriage The carriage 28 is a substantially rectangular flat plate, and is supported by the guide rail 34 in an inclined state in which the lower end edge protrudes forward from the upper end edge. Engaging portions 28a and 28b for fixing the traction belt 32 are provided at the center in the sub-scanning direction at the left edge and the right edge of the carriage 28, respectively. Then, a leftward moving force F is applied from the left engaging portion 28a by the traction belt 32, and the carriage 28 moves to the left in the main scanning direction, which is the forward path, and conversely from the right engaging portion 28b. Moves to the right side of the return path with a rightward moving force F applied.

  FIG. 2 shows a front view of the carriage 28 as viewed from the platen 26 side described later. The carriage 28 is provided with a print head 136 having a full length H1 that is long in the transport direction. The print head 136 is provided with a number of nozzles n that eject ink at a predetermined pitch k · D in the transport direction. The total length H1 is the distance between the uppermost nozzle and the lowermost nozzle of the print head 136. D is a dot pitch in the sub-scanning direction, and k is an integer of 1 or more.

  The print head 136 is equally divided into eight nozzle groups 36a, 36b,... 36h in the transport direction, and ink discharge can be started and stopped from the nozzle n for each nozzle group 36. Yes.

FIG. 3 shows an enlarged view of the nozzle group 36. In the nozzle group 36, the 180 nozzles n are arranged in a row at a predetermined pitch k · D along the sub-scanning direction. A nozzle row N having a total length H0 is configured. The total length H0 is the distance between the uppermost nozzle n1 and the lowermost nozzle n180, and the total length H1 of the print head 136 is in the relationship of the following equation a.
H1 = 8 × H0 + 7 × k · D (Formula a)

Six nozzle rows N are provided for each nozzle group 36, and these nozzle rows N are arranged in parallel at the design pitch Wn in the main scanning direction. The arrangement of the nozzle group 36 and the nozzle n will be described later.

  As shown in FIGS. 1 and 2, the carriage 28 has an end detection sensor for detecting the left and right end positions of the roll paper P in correspondence with the nozzle groups 36a, 36b,. 361, 361,... 361 are provided. The end detection sensor 361 serves to start and stop ink ejection, and is disposed adjacent to the side of the nozzle group 36 in charge of each. This end detection sensor 361 will also be described later.

(1-B) Guide Rail As shown in FIG. 1, two guide rails 34 are provided along the main scanning direction. These guide rails 34 are vertically arranged at intervals in the sub-scanning direction, and are supported by frames (not shown) serving as bases on the left and right ends. The two guide rails 34 are arranged such that the lower guide rail 341 is disposed in front of the upper guide rail 342, and the carriage 28 spanned between them is, as described above, the lower end edge thereof. While moving in a main scanning direction while maintaining the tilted state protruding forward, the head is moved back and forth.

  The guide rail 342 is provided with a linear encoder code plate 19, which is a component of the position detection sensor 18 of the carriage 28, along the guide rail 342. A linear encoder 17 that is another component of the position detection sensor 18 is fixed to the carriage side 28. Thus, the current position of the carriage 28 in the main scanning direction can be recognized. The position detection sensor 18 will be described later.

(1-C) Traction Belt The traction belt 32 is a metal belt, and one end of the traction belt 32 passes through the left engagement portion 28a of the carriage 28, and the other end passes through the rear side of the carriage 28 and the right belt. It is fixed to the engaging portion 28b. The traction belt 32 is wound around a pair of pulleys 44 a and 44 b provided at the left and right movement stroke ends of the carriage 28. The carriage motor 30 is connected to one of the pulleys 44a, and the carriage motor 30 applies a moving force F in the main scanning direction to the carriage 28 via the traction belt 32. As a result, the carriage 28 reciprocates in the left and right directions.

(1-D) Position Detection Sensor FIG. 4 schematically shows the configuration of the position detection sensor 18 attached to the carriage 28. The position detection sensor 18 includes a linear encoder code plate 19 fixed to the guide rail 342 and a linear encoder 17 fixed to the carriage 28.

The linear encoder code plate 19 has slits formed at predetermined intervals along the main scanning direction.
The linear encoder 17 includes a light emitting diode 17a, a collimator lens 17b, and a detection processing unit 17c. The detection processing unit 17c includes a plurality of (for example, four) photodiodes 17d, a signal processing circuit 17e, and, for example, two comparators 17fA and 17fB.

  When the voltage VCC is applied to both ends of the light emitting diode 17a via a resistor, light is emitted from the light emitting diode 17a. This light is condensed into parallel light by the collimator lens 17 b and passes through the linear encoder code plate 19. The linear encoder code plate 19 is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 2.54 cm)).

  The parallel light that has passed through the linear encoder code plate 19 enters each photodiode 17d through a fixed slit (not shown), and is converted into an electrical signal. The electric signals output from the four photodiodes 17d are subjected to signal processing in the signal processing circuit 17e, the signals output from the signal processing circuit 17e are compared in the comparators 17fA and 17fB, and the comparison result is output as a pulse signal. Pulses ENC-A and ENC-B output from the comparators 17 fA and 17 fB are output from the encoder 17.

5A and 5B are timing charts showing waveforms of two output signals of the linear encoder 17 during forward rotation and reverse rotation of the carriage motor.
As shown in FIGS. 5A and 5B, the pulse ENC-A and the pulse ENC-B are different in phase by 90 degrees in both cases of forward rotation and reverse rotation of the carriage motor. When the carriage motor 30 is rotating forward, that is, when the carriage 28 is moving in the forward direction, the phase of the pulse ENC-A is advanced by 90 degrees from the pulse ENC-B as shown in FIG. 5A. When the carriage motor 30 is rotating in reverse, that is, when moving in the backward direction, the phase of the pulse ENC-A is delayed by 90 degrees from the pulse ENC-B, as shown in FIG. 5B. One period T of the pulse ENC-A and the pulse ENC-B is equal to the time during which the carriage 28 moves through the slit interval of the linear encoder code plate 19.

  In the present embodiment, the slit (white portion) width of the code plate 19 for the linear encoder corresponds to twice the resolution of the color printer 20, for example, 360 dpi here. That is, when the carriage 28 scans in the main scanning direction, it is detected that the distance corresponding to 360 dpi is moved every time a pulse signal is output from the encoder 17. Therefore, for example, in the initial operation when the color printer 20 is activated, the home position set in advance to be the standby position of the carriage 28 is recognized, and then the pulse signal output from the linear encoder 17 is counted, whereby the carriage It is possible to detect the current position in the 28 main scanning direction.

  Further, by dividing the pulse signal output from the linear encoder 17 into equal parts, the position of the carriage 28 can be detected with higher resolution than the slits of the linear encoder code plate 19. For example, when the pulse signal output from the linear encoder 17 is divided into four, the position of the carriage 28 can be detected and controlled with an accuracy of 1440 dpi.

(1-E) Edge Detection Sensor FIG. 6 is a schematic diagram for explaining an example of the edge detection sensor 361. The end detection sensor 361 is, for example, a reflective optical sensor 361. In this example, a light emitting unit 363 configured by a light emitting diode, a light receiving unit 365 configured by a phototransistor, and an electric signal measuring unit 367 are provided. Have. Light emitted from the light emitting unit 363, that is, incident light, is reflected by the platen 26 when there is no roll paper P in the direction of the roll paper P or emitted light, and the reflected light is received by the light receiving unit 365 to be electrically Converted to a signal. And the magnitude | size of an electrical signal is measured as an output value of the light-receiving part according to the intensity of the received reflected light. The magnitude of this electric signal varies depending on whether the reflected material is the platen 26 or the roll paper P. For this reason, this size is measured by the electric signal measuring unit 367, and when it changes smaller than a predetermined threshold or when it changes larger than the threshold, the end of the roll paper P is approached. Assuming that the electrical signal measuring unit 367 outputs a detection signal. This detection signal is transmitted to the margin setting section 224, which will be described later, and used for setting the ink discharge start position and the discharge stop position.

In the above description, as shown in FIG. 6, the light emitting unit 363 and the light receiving unit 365 are integrated to form a device called a reflective optical sensor 361. However, like the light emitting device and the light receiving device, respectively. A separate device may be configured.
In the above, in order to obtain the intensity of the received reflected light, the magnitude of the electric signal is measured after converting the reflected light into an electric signal. However, the present invention is not limited to this. The output value of the light receiving unit corresponding to the intensity of the reflected light may be measured.

――― (2) Paper transport section ―――
As shown in FIG. 1, the paper transport unit 5 for transporting the roll paper P is provided on the back side of the two guide rails 34. The paper transporting unit 5 transports the roll paper P below the lower guide rail 341 and the roll paper holding unit 35 that rotatably holds the roll paper P, and above the upper guide rail 342. A roll paper transport unit 37 and a platen 26 along which the roll paper P transported between the roll paper holding unit 35 and the roll paper transport unit 37 are arranged.

(2-A) Platen The platen 26 has a flat surface extending over the entire width of the roll paper P to be conveyed, and this flat surface is provided so as to be parallel to the flat surface of the carriage 28 that scans in the inclined state. It has been. The platen 26 is opposed to the surface of the print head 136 assembled to the carriage 28 with an equal interval across the entire surface.

(2-B) Roll Paper Holding Unit The roll paper holding unit 35 includes a holder 27 that rotatably holds the roll paper P. The holder 27 has a shaft body 27a that serves as a rotation shaft in a state where the roll paper P is held, and guide disks for suppressing the skew of the roll paper P to be supplied at both ends of the shaft body 27a. 27b are provided.

(2-C) Roll Paper Transport Unit The roll paper transport unit 37 sandwiches the roll paper P between the map roller 24 for transporting the roll paper P and the map roller 24 disposed opposite thereto. The roller 24a and the conveyance motor 31 for rotating the map roller 24 are provided. A drive gear 40 is provided on the shaft of the transport motor 31, and a relay gear 41 that meshes with the drive gear 40 is provided on the shaft of the map roller 24. The power of the transport motor 31 is provided via the drive gear 40 and the relay gear 41. It is transmitted to the map roller 24. That is, the roll paper P held by the holder 27 is sandwiched between the map roller 24 and the sandwiching roller 24 a, and the roll paper P is transported along the platen 26 by the transport motor 31.

=== Configuration of Nozzle Group ===
As shown in FIG. 3, the nozzle group 36 has six nozzle rows N in which a large number of nozzles n are aligned in a straight line along the sub-scanning direction, and these nozzle rows N are arranged in the main scanning direction. Are arranged in parallel at a design pitch Wn. In the present embodiment, as the nozzle row N, a black nozzle row Nk, a cyan nozzle row Nc, a light cyan nozzle row Nlc, a magenta nozzle row Nm, a light magenta nozzle row Nlm, and a yellow nozzle row Ny are provided for each ink color to be ejected. Is lined up.

  Each nozzle row N has 180 nozzles n1 to n180, and each nozzle n is provided with a piezo element (not shown) as a drive element for driving the nozzle n to eject ink. ing. The nozzles n1, n2,..., N180 in the nozzle array N are arranged at a constant nozzle pitch k · D along the sub-scanning direction. Here, D is a dot pitch in the sub-scanning direction, and k is an integer of 1 or more. The dot pitch D in the sub-scanning direction is equal to the pitch of the main scanning line (raster line).

  At the time of printing, the roll paper P is intermittently transported by a predetermined transport amount by the paper transport unit 5, and the carriage 28 moves in the main scanning direction during the stop in the intermittent transport, and from each nozzle n during this movement Ink is ejected. However, depending on the printing method, not all nozzles n are always used, and only some of the nozzles n may be used.

=== Driving of nozzle group ===
Next, driving of the nozzle group 36 related to the print head 136 will be described with reference to FIG.

FIG. 7 is a block diagram showing the configuration of the drive signal generator 200 provided in the nozzle group control unit 63 (FIG. 9).
The drive signal generator 200 is provided independently for each nozzle group 36, and the ink ejection timing can be adjusted for each nozzle group 36.
The drive signal generation unit 200 includes an original drive signal generation unit 206, an original drive signal shift correction unit 207, a plurality of mask circuits 204, and a margin setting unit 224.

  The original drive signal generator 206 generates an original drive signal ODRV that is used in common by the nozzles n1 to n180. This original drive signal ODRV is divided into two pulses, a first pulse W1 and a second pulse W2, within the scanning period for one pixel (within the time during which the carriage crosses the interval of one pixel) as shown in the lower part of the figure. It is a signal containing. The generated original drive signal ODRV is output to the drive signal shift correction unit 207.

  The drive signal shift correction unit 207 shifts the waveform of the original drive signal ODRV back and forth over the entire return path. As a result, the deviation of the ink landing position in the forward path and the backward path of the main scanning is corrected, that is, the deviation of the dot formation position in the forward path and the backward path is corrected.

  The mask circuit 204 is provided corresponding to each piezo element that drives each nozzle n1 to n180. Each mask circuit 204 receives the original drive signal ODRV from the original drive signal shift correction unit 207 and also receives a print signal PRT (i) based on print data PD described later.

  The print signal PRT (i) is pixel data corresponding to a pixel, and is a serial signal having 2-bit information for one pixel. Each bit of the print signal PRT (i) is applied to the first pulse W1 and the second pulse W2, respectively. It corresponds. The mask circuit 204 blocks or passes the original drive signal ODRV according to the level of the print signal PRT (i). That is, when the print signal PRT (i) is 0 level, the pulse of the original drive signal ODRV is cut off so as not to eject ink, and when the print signal PRT (i) is 1 level, the original drive signal ODRV The corresponding pulse is passed as it is and is output as a drive signal DRV (i) to the piezo element via the drive signal shift correction unit 207, thereby ejecting ink from the nozzles.

  In the present invention, the mask circuit 204 receives a margin signal SIG from the margin setting unit 224 in addition to the print signal PRT (i). This margin signal SIG defines the margins formed at the left and right ends of the roll paper P, and is composed of a 1 level signal for starting ink ejection and a 0 level signal for stopping ink discharge. Is done. That is, whether or not the drive signal DRV (i) after passing through the mask circuit 204 is a signal for ejecting ink is a logical product (so-called AND) of the print signal PRT (i) and the margin signal SIG. It is determined by the calculation result of (A).

  FIG. 8 is an explanatory diagram of the margin signal. This margin signal SIG basically becomes one level when the nozzle group 36 moving in the main scanning direction reaches one end of the roll paper P, and reaches the other end across the roll paper P as it is. 0 level. As a result, ink is ejected almost only on the roll paper P based on the print signal PRT (i), and a print image is printed on the roll paper P.

  Selection of “printing with margins” with margins or “printing without margins” without margins is performed by adjusting the switching position Pc of the margin signal SIG. For example, if the switching position Pc of the margin signal SIG from 0 to 1 level is set inside the end of the roll paper P, a margin is formed at the end of the roll paper P, while the switching position Pc is the same. Is set to the outside, no margin is formed at the end of the roll paper P, and a print image is printed without a border.

  Note that the distance from the end to the switching position Pc (hereinafter referred to as marginless margin M) at the time of “marginless printing” is set in consideration of the skew of the roll paper P and the like. If the line is within the design tolerance, borderless printing is ensured. The marginless margin M will be described later.

  Further, the position of the end is detected by the end detection sensor 361, and the margin setting unit 224 that has received this detection signal uses the position of the carriage 28 at the time of reception as the position detection sensor. 18 from. Then, a position outside the edge position by the marginless margin M is recorded as a discharge start position or a discharge stop position as the switching position Pc.

=== Example of Control Configuration of Liquid Discharge Device ===
Next, a control configuration example of the color printer 20 as a liquid ejection apparatus will be described with reference to FIGS. 9 and 10. FIG. 9 is a block diagram showing a control configuration of the color printer 20, and FIG. 10 is a block diagram showing a configuration of the image processing unit 38.
The color printer 20 is used by being connected to a computer 90 such as a personal computer, and prints a print image on the roll paper P based on image data transmitted from the computer 90. The above configuration in which the computer 90 is added to the color printer 20 can also be referred to as a “liquid ejecting apparatus” in a broad sense.

  The computer 90 includes a CRT 21, a display device such as a liquid crystal display device (not shown), an input device such as a keyboard and a mouse, a drive device such as a flexible drive device and a CD-ROM drive device. In the computer 90, an application program 95 operates under a predetermined operating system. The operating system incorporates a video driver 91, and an application program 95 that performs image retouching or the like performs desired processing on the image to be processed, and also sends an image to the CRT 21 via the video driver 91. indicate.

  The color printer 20 includes an image processing unit 38 serving as information generation means to which image data and the like from the application program 95 are input, a system controller 54 that controls the operation of the entire color printer 20, a RAM 56, and a ROM 58. Yes. The system controller 54 further includes a main scanning drive circuit 61 for driving the carriage motor 30, a sub-scanning drive circuit 62 for driving the carry motor 31, and the nozzle groups 36. Eight nozzle group control units 63 as control means for controlling 36 and a position detection sensor 18 for detecting the position of the carriage 28 are connected.

  Each nozzle group control unit 63 is connected to the end detection sensor 361. The edge detection sensor 361 detects the edge of the roll paper P during main scanning, and simultaneously transmits this detection signal to the margin setting unit 224 in the nozzle group control unit 63. The margin setting unit 224 that has received the detection signal acquires a pulse signal indicating the position of the carriage 28 at the time of reception from the position detection sensor 18. Then, the margin setting unit 224 sets the ink discharge start position and the discharge stop position at the next main scanning based on the end position information.

  Under such a control configuration, when the application program 95 issues a print command, the image processing unit 38 provided in the color printer 20 receives the image data from the application program 95 and converts it into print data PD. As shown in FIG. 10, the image processing unit 38 includes a resolution conversion module 97, a color conversion module 98, a halftone module 99, a rasterizer 100, a UI printer interface module 102, and a raster data storage unit. 103, a color conversion lookup table LUT, a buffer memory 50, and an image buffer 52 are provided.

  The resolution conversion module 97 plays a role of converting the resolution of the color image data formed by the application program 95 into a corresponding print resolution based on information such as the print mode received together with the image data. The image data thus converted in resolution is still image information composed of three color components of RGB. The color conversion module 98 converts RGB image data for each pixel into multi-tone data of a plurality of ink colors that can be used by the color printer 20 while referring to the color conversion lookup table LUT.

  The color-converted multi-gradation data has, for example, 256 gradation values. The halftone module 99 performs so-called halftone processing to generate halftone image data.

  The halftone image data is rearranged in the desired data order by the rasterizer 100 and output to the raster data storage unit 103 as final print data PD. The print data PD includes raster data indicating the dot formation state during each main scan and data indicating the sub-scan feed amount.

  On the other hand, the user interface display module 101 provided in the computer 90 has a function of displaying various user interface windows related to printing and a function of receiving user input in these windows. For example, the user can instruct the user interface display module 101 about the paper type, size, print mode, and the like.

  The UI printer interface module 102 has a function as an interface between the user interface display module 101 and the color printer 20. The user interprets a command instructed by the user interface display module 101 and transmits various commands COM to the system controller 54 or the like, or conversely interprets the command COM received from the system controller 54 or the like, and the user interface display module. Various displays are performed on the screen 101. For example, the instruction relating to the paper type, size, print mode, etc. received by the user interface display module 101 is sent to the UI printer interface module 102, and the UI printer interface module 102 interprets the instructed instruction. A command COM is transmitted to the system controller 54. Then, based on the print mode, print information (resolution of the image to be printed, information on the nozzle used for printing, information on the data indicating the sub-scan feed amount), the print data PD is converted into the halftone module 99 or the rasterizer. 100 and output to the raster data storage unit 103.

  The print data PD output to the raster data storage unit 103 is temporarily stored in the buffer memory 50, converted into data corresponding to the nozzles, and stored in the image buffer 52. The system controller 54 of the color printer 20 controls the main scanning drive circuit 61, the sub-scanning driving circuit 62, the nozzle group control unit 63, etc. based on the information of the command COM output from the UI printer interface module 102, and the image buffer 52. Based on the data, the nozzles of the respective colors provided in the print head 36 are driven to perform printing.

  The print mode is mainly composed of a color defining mode for defining the color of the print image and an image quality defining mode for defining the image quality of the print image, and is defined by a combination thereof. Of these, as the color regulation mode, either a full color mode in which printing is performed using all the six colors of ink or a monochrome mode in which printing is performed using a single color ink such as only black ink can be selected and set. On the other hand, the image quality defining mode is a so-called interlace method (a method of forming a raster line (a line in the main scanning direction in a printed image) with a dot pitch D in the sub scanning direction smaller than the nozzle pitch k · D). Either a high image quality mode in which dots are recorded using a method in which raster lines adjacent in the scanning direction are formed by different nozzles, or a so-called band method (by one scan, raster lines for the entire length H of the print head are generated. It is possible to select and set one of the high-speed modes in which dots are recorded at high speed using a nozzle pitch k · D method. The ink used for the monochrome mode is not limited to the black ink, and other inks such as cyan ink may be used. The high image quality mode is not limited to the interlace method, and may be a so-called overlap method in which one raster line (one line in the main scanning direction in the printed image) is printed a plurality of times, or a combination thereof. The method may be used.

=== Borderless printing operation of the liquid ejection device ===
Here, the borderless printing operation of the color printer 20 as the liquid ejecting apparatus will be described with reference to the flowchart of the printing operation shown in FIG.

  First, the user instructs to perform printing in the application program 95 or the like. When the application program 95 that has received this instruction issues a print command, the system controller 54 that has received this print command receives each image data from the application program 95 to the eight image processing units 38a, 38b,. (S101). These image processing units 38a, 38b,... 38h convert each image data into print data PD, and then transmit it to the buffer memory 50. Each of the image processing units 38a, 38b,... 38h receives the print data PD corresponding to each of the nozzle groups 36a, 36b,.

  The user can instruct the print mode and the like from the user interface display module 101 together with the print instruction by the application program 95. The instruction from the user is sent to the UI printer interface module 102 of each image processing unit 38a, 38b,. The UI printer interface module 102 interprets the instructed command and sends a command COM to the system controller 54.

  Next, the system controller 54 performs a paper feed process based on the command COM (S102). The paper feed process is a process for unwinding the roll paper P by an appropriate amount necessary for printing and facing the platen 26, and is executed by driving the transport motor 31 by the sub-scanning drive circuit 62 or the like.

Next, the system controller 54 alternately repeats the dot formation process (S103) and the conveyance process (S104) to print the print image on the roll paper P. The dot forming process is a process for forming dots on the roll paper P by ejecting ink from the nozzle groups 36a, 36b,... 36h while moving the carriage 28 in the main scanning direction. Further, the conveyance process is a process for conveying the roll paper P by a predetermined conveyance amount in the sub-scanning direction. Here, the movement of the carriage 28 in the main scanning direction is performed by causing the main scanning driving circuit 61 to drive the carriage motor 30, and the ink ejection from each of the nozzle groups 36a, 36b,. Each of the nozzle group control units 63a, 63b,... 63h is driven by driving the corresponding nozzle group 36, and the roll paper P is transported by driving the transport motor 31 by the sub-scanning drive circuit 62. Do.
The dot formation process and the conveyance process are repeatedly executed until the print data PD disappears (S105). When the print data PD disappears, the print image is completed on the roll paper P, and the printing operation ends.

  The “ink ejection operation” related to the “dot formation process” described above is executed with reference to the end position of the roll paper P detected during the main scanning. That is, during the main scanning, not only the “ink ejection operation” but also the “end edge position detection operation” of the roll paper P is performed. Based on the edge position detected during the main scanning, A position for starting the discharge (discharge start position) and a position for stopping the discharge (discharge stop position) are set.

  Here, the “dot formation process” will be described in detail. FIG. 12 is a flowchart of the dot forming process, and FIGS. 13A to 13J are explanatory diagrams showing the state of the nozzle group 36 that performs main scanning in the dot forming process. In the following description, one nozzle group 36 will be described, but it goes without saying that the remaining seven nozzle groups 36 operate in the same manner. In order to avoid complicated explanation, the “ink ejection operation” and the “detection operation of the end position of the roll paper P” will be described separately, but these two operations are shown in FIG. As shown, it is executed in parallel during the main scan.

  First, the “detection operation of the end position of the roll paper P” will be described. Before the carriage 28 performs main scanning by the main scanning drive circuit 61, the nozzle group control unit 63 controls the end detection sensor 361 and emits light from the light emitting unit 363 toward the platen 26. Then, as shown in FIG. 13A, the carriage motor 30 is driven by the main scanning drive circuit 61 to move the carriage 28 in the forward direction (S200). Eventually, as shown in FIG. 13B, the light emitted from the light emitting unit 363 is blocked by one end of the roll paper P. At this time, the light emitted from the light emitting unit 363 is incident. Since the platen 26 changes to the roll paper P first, the magnitude of the electrical signal that is the output value of the light receiving unit 365 that receives the reflected light changes and falls below the threshold value. Then, the end detection sensor 361 considers that the end position has been detected, and transmits the detection signal to the margin setting unit 224 (S230). The margin setting unit 224 that has received this detection signal acquires a pulse signal indicating the position of the carriage 28 at the time of reception from the position detection sensor 18 as end position information (S222, S223). The margin setting unit 224 records a position outside the edge position by the marginless margin M as an ink ejection stop position at the next main scanning (S224). Needless to say, the discharge stop position is recorded for each end detection sensor 361, that is, for each nozzle group 36.

  When the carriage 28 continues the main scanning as it is, the light emitted from the light emitting unit 363 of the end detection sensor 361 reaches the other end of the roll paper P as shown in FIG. 13D through FIG. 13C. It is not blocked by the roll paper P. At this time, since the incident destination of the light emitted from the light emitting unit 363 is changed from the roll paper P to the platen 26, the electric signal of the light receiving unit 365 exceeds a predetermined threshold value. Then, the edge detection sensor 361 considers that the edge position has been detected, and transmits a detection signal of the edge position to the margin setting unit 224 (S231). The margin setting unit 224 that has received this detection signal acquires a pulse signal indicating the position of the carriage 28 at the time of reception from the position detection sensor 18 as end position information (S225, S226). Then, the margin setting unit 224 records a position outside the edge position by the marginless margin M as an ink discharge start position at the next main scanning (S227). Needless to say, the recording of the discharge start position is performed for each end detection sensor 361, that is, for each nozzle group 36.

  Then, as shown in FIG. 13E, when the main scanning carriage 28 reaches the main scanning stop position, the main scanning drive circuit 201 constantly monitoring the pulse signal of the position detection sensor 18 stops the carriage 28. (S201).

  In the foregoing, the “detection operation of the edge position of the roll paper P” has been described for the main scanning in the forward path, but the same applies to the backward path.

  Next, the “ink ejection operation” will be described. For convenience of explanation, this main scanning is assumed to be the next main scanning that is continued after the main scanning used in the explanation. Further, in order to avoid complicated explanation, the above-mentioned “detection operation of the edge of the roll paper P” will be omitted, but the “edge of the roll paper P” is also described during the main scanning described below. Needless to say, the "detection operation" is performed.

  First, as shown in FIG. 13F, the carriage motor 30 is driven by the main scanning drive circuit 61 to move the carriage 28 in the backward direction (S200). Eventually, as shown in FIG. 13G, the nozzle group 36 reaches a position outside the edge position of the roll paper P by the margin M for margins. This position is a blank space as a discharge start position during the previous main scan. This is the position recorded by the setting unit 224. Accordingly, the margin setting unit 224 that monitors the pulse signal from the position detection sensor 18 detects the ejection start position of the nozzle group 36 (S220), and the margin setting unit 224 changes the margin signal from 0 to 1 level. Switching is started and ink ejection is started (S221). Needless to say, this discharge start is performed for each nozzle group 36.

  Then, when the carriage 28 continues the main scanning as it is, the nozzle group 36 approaches the position outside the edge position by the marginless margin M as shown in FIG. 13I through FIG. 13H. This position is a position recorded as a discharge stop position during the previous main scan. Accordingly, the margin setting unit 224 that monitors the pulse signal from the position detection sensor 18 detects the ejection stop position of the nozzle group 36 (S228), and the margin setting unit 224 changes the margin signal from 1 to 0 level. Switching is performed to stop ink ejection (S229). Needless to say, this discharge stop is performed for each nozzle group 36.

  When the main scanning carriage 28 reaches the main scanning stop position, the main scanning driving circuit 201 that constantly monitors the pulse signal of the position detection sensor 18 stops the carriage 28 (S201).

  In the above, the “ink ejection operation” has been described for the main scanning in the backward path, but the same applies to the forward path.

=== Margin for borderless ===
14A and 14B are explanatory diagrams of the marginless margin M. FIG. Unlike the embodiment, the print head 136a shown in the figure as a general example includes only one end detection sensor 361. Then, at the time of borderless printing, a position Pc separated from the left edge position and the right edge position of the roll paper P detected by the edge detection sensor 361 to the outside by a margin M for margin. The discharge is started and stopped at.

Here, the marginless margin M is set in consideration of the design tolerance of the skew angle (tilt angle) of the roll paper P, as shown in FIG. 14B. Even if a line occurs, no margin is formed at the end of the roll paper P. That is, the marginless margin M is calculated by the following equation 1 from the designed maximum skew angle θm and the total length H of the print head.
M = H × tan θm (Formula 1)

  In addition, the reason for calculating with Equation 1 is as follows. As shown in FIG. 14B, when the roll paper P is skewed, one of the uppermost nozzle n and the lowermost nozzle n of the print head 136a to be main-scanned is the roll paper first. To reach the end of P and the other will arrive later, but in order to print without borders, when one reaches the end, the print head 136a moves from the nozzle n over its entire length H. This is because ink must be discharged.

Here, it can be seen from Equation 1 that the margin M for marginless increases as the total length H of the print head 136a increases. Accordingly, when the entire length H1 of the print head 136 is long as in the present embodiment shown in FIG. 1, the necessary margin M1 is also large as shown in FIG. However, the ink yield associated with borderless printing becomes very poor.
Therefore, in order to avoid this, in the present invention, the print head 136 is divided into eight nozzle groups 36, 36,... 36 with respect to the transport direction, and for each of the nozzle groups 36. A dedicated end detection sensor 361 is provided so that the end position of the roll paper P is individually detected for each nozzle group 36 and ink is ejected.

Then, as shown in FIG. 15B, the total length H0 of each nozzle group 36 is approximately one-eighth of the total length H1 of the print head 136, so that the margin M0 necessary for each nozzle group 36 is obtained. However, as shown in the following Expression 2, the marginless margin M1 can be reduced to approximately one-eighth.
M0 = H0 × tan θm
≒ H1 / 8 x tanθm
= M1 / 8 (Formula 2)
To generalize this, “Long print heads are divided into a predetermined number of nozzle groups in the transport direction, and the end position of the roll paper is detected for each nozzle group so that ink can be ejected. In this case, the necessary marginless margin M can be reduced to a predetermined number of times. "

  Here, desirably, the actual value θa of the skew angle of the roll paper P is obtained by using the two end position information acquired by using at least two of the eight end detection sensors 361 and 361. It is good to calculate. Then, the minimum margin Ma required can be calculated from the actual value θa, so that the margin M0 calculated on the safe side from the maximum skew angle can be eliminated, and a margin without margin can be further added. It can be made smaller.

The actual value θa of the skew angle is calculated by the following equation 3, for example.
θa = arctan ((X1−X2) / S) (Formula 3)

Here, X1 and X2 are end positions based on end position information of the two end detection sensors 361 and 361, and S is a distance in the sub-scanning direction of the two end detection sensors 361 and 361. .
Further, the end position detection by the end detection sensors 361 and 361 is preferably performed in the main scan immediately before the current main scan, as described in “Borderless printing operation”. This is because the latest skew state of the roll paper P can be reflected.

=== Another Arrangement Example of Nozzle Group and Edge Detection Sensor ===
In the above-described embodiment, as an example of the arrangement of the nozzle group 36 on the carriage 28, an example in which the nozzle group 36 is arranged in a straight line along the sub-scanning direction has been described. However, the arrangement is not limited to this, and FIG. The present invention can be applied to various modes as shown in FIG. These drawings are plan views of the carriage 28 as viewed from the platen side. Also, in any of the three arrangement examples described below, the end detection sensor 361 is provided in the vicinity of the nozzle group 36 in charge of each, and is provided on the upstream side in the transport direction on the right side. Since both are the same, description thereof is omitted.

  First, the arrangement example shown in FIG. 16 will be described. In this arrangement example, among the eight nozzle groups 36 provided on the carriage 28, the four nozzle groups 36 are arranged above the traction belt 32, and the remaining four nozzle groups 36 are below the traction belt 32. Is arranged. Since the upper and lower arrangements are the same, the positional relationship among the upper four nozzle groups 36 will be described below as an example.

  The four nozzle groups 36 are arranged in two stages in the vertical direction, and the upper two nozzle groups 36a, 36b and the lower two nozzle groups 36c, 36d are approximately the width of the nozzle group 36 in the left-right direction. They are arranged at equal intervals. The nozzle group 36 b located on the right side of the upper stage is located at the right end of the carriage 28, and the nozzle group 36 c located on the left side of the lower stage is located at the left end of the carriage 28. That is, out of the four nozzle groups 36a, 36b, 36c, and 36d, the two nozzle groups 36a and 36c located on the left side and the two nozzle groups 36b and 36d located on the right side make a pair, and each of the two pairs The nozzle groups 36c and 36d located on the left side of the nozzle group 36 are located on the lower stage, and the nozzle groups 36a and 36b located on the right side are located on the upper stage side and arranged in a staggered manner.

  Further, the four nozzle groups 36 have a pitch between the lowermost nozzle n180 of the nozzle row provided in the upper nozzle group 36 and the uppermost nozzle n1 of the nozzle row provided in the lower nozzle group 36. The nozzle rows are arranged to be equal to the nozzle pitch k · D. That is, between the two nozzle groups 36a and 36c arranged on the left side, the lowermost nozzle n180 (the last nozzle in the transport direction) of the nozzle row of the nozzle group 36a arranged on the upper right and the lower left nozzle The nozzle row of the group 36c is arranged so that the distance from the uppermost nozzle n1 (the most advanced nozzle in the transport direction) of the nozzle row is the nozzle pitch k · D in the vertical direction. Further, between the two nozzle groups 36b and 36d arranged on the right side, the lowermost nozzle n180 of the nozzle row included in the upper right nozzle group 36b and the uppermost nozzle n1 of the nozzle row included in the lower left nozzle group 36d. The nozzle pitch k · D is arranged in the vertical direction. Therefore, in one main scan of the carriage 28, for example, the two nozzle groups 36a and 36c located on the left side and the two nozzle groups 36b and 36d located on the right side are treated as one class, and each class is When dots are formed at the same position in the main scanning direction with respect to the roll paper P in each nozzle row, the dots formed by the nozzle rows of two similar nozzle groups 36 are continuously formed at an equal pitch. . That is, by controlling the timing at which ink is ejected from the nozzle rows of two similar nozzle groups, these nozzle rows can be handled as one continuous nozzle row. For this reason, even when printing a large image on a large sheet, it is possible to print at high speed.

  Next, the arrangement example shown in FIG. 17 will be described. In this arrangement example, the eight nozzle groups 36 provided on the carriage 28 are paired in pairs arranged in the main scanning direction, and four nozzle group pairs 36A, 36B, and 36C forming the pairs. , 36D, the first nozzles n1 of the nozzle rows N of the nozzles N are disposed at intervals in the main scanning direction. Here, when the width of the roll paper P in the main scanning direction is Wp, the interval between the first nozzles n1 of the nozzle group pairs 36A, 36B, 36C, 36D is arranged to be 1/2 Wp. Yes. The nozzle group located on the left side of the pair of nozzle groups 36A, 36B, 36C, 36D forming a pair is the first nozzle group 36a, 36c, 36e, 36g, and the nozzle group located on the right side is the second nozzle group 36b, 36d, 36f, 36h, in the first nozzle group and the second nozzle group, the nozzle located at one end in the main scanning direction, for example, the black nozzle included in the first nozzle group 36a in the uppermost nozzle group pair 36A The first nozzle n1 in the row Nk and the first nozzle n1 in the black nozzle row Nk of the second nozzle group 36b are arranged so that the interval in the main scanning direction is ½ Wp.

  In addition, each nozzle row included in each first nozzle group and each nozzle row included in each second nozzle group of each of the nozzle group pairs 36A, 36B, 36C, and 36D arranged in four stages in the vertical direction is a roll paper. It is positioned so as to be arranged substantially in a straight line in the sub-scanning direction, which is the P transport direction. Further, the distance between the first nozzle n1 of the nozzle group pair 36A located at the uppermost stage and the nozzle group pair 36B located at the second stage is located at the nozzle group pair 36B located at the second stage and the third stage. The distance between the first nozzle n1 of the nozzle group pair 36C is equal to the distance L1 between the first nozzle n1 of the nozzle group pair 36C located at the third stage and the nozzle group pair 36D located at the lowest stage. Is arranged.

  Finally, an arrangement example shown in FIG. 18 will be described. In this arrangement example, four nozzle groups 36 are arranged in the left region and four nozzle groups 36 are arranged in the right region with respect to the center in the left-right direction of the carriage 28, and the nozzle groups in each region are arranged. 36 are aligned in a straight line at a design pitch 2L0 (= 2 (H0 + k · D)) along the sub-scanning direction. That is, in each region, the nozzle groups 36 adjacent to each other in the sub-scanning direction are arranged with an interval corresponding to one nozzle group 36 therebetween. H0 indicates the total length of the nozzle row N.

  On the other hand, the nozzle groups 36 adjacent to the left and right are arranged at the design pitch Wh in the main scanning direction and are shifted from each other by half of the design pitch 2L0 in the sub-scanning direction. The groups 36 are arranged in a staggered pattern on the left and right on the carriage 28 plane. Specifically, the nozzle group 36 in the other one side region (for example, the right side region) is arranged in correspondence with the interval portion where the nozzle group 36 does not exist in the one side region (for example, the left side region). The gap portions where the nozzle groups 36 do not exist in the respective regions are supplemented with each other. Therefore, for example, when the eight nozzle groups 36 on the carriage 28 are combined, it is equivalent to having a nozzle row that is approximately eight times as long as the nozzle row N, thereby printing a large print image in a very short time. It is possible to execute with.

=== Other Embodiments ===
As mentioned above, although the liquid discharge apparatus etc. which concern on this invention have been demonstrated based on one Embodiment, Embodiment mentioned above is for making an understanding of this invention easy, and limits this invention. is not. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  For example, the embodiments described below are also included in the liquid ejection apparatus according to the present invention. That is, a color filter manufacturing apparatus, a dyeing apparatus, a fine processing apparatus, a semiconductor manufacturing apparatus, a surface processing apparatus, a three-dimensional modeling machine, a liquid vaporizing apparatus, an organic EL manufacturing apparatus (particularly a polymer EL manufacturing apparatus), a display manufacturing apparatus, and a film formation You may apply the same technique as this embodiment to an apparatus, a DNA chip manufacturing apparatus, etc. These methods and manufacturing methods are also within the scope of application.

  In the above-described embodiment, ink such as dye ink or pigment ink is ejected from the nozzle n. However, the liquid ejected from the nozzle n is not limited to such ink. For example, liquids (including water) including metal materials, organic materials (especially polymer materials), magnetic materials, conductive materials, wiring materials, film-forming materials, electronic inks, processing liquids, gene solutions, etc. are ejected from nozzles. May be. If such a liquid is directly discharged toward the object, material saving, process saving, and cost reduction can be achieved.

  In the above-described embodiment, ink is ejected using a piezo element. However, the method for discharging the liquid is not limited to this. For example, other methods such as a method of generating bubbles in the nozzle by heat may be used.

  In the above-described embodiment, the roll paper P has been described as an example of the paper. However, a single-sheet paper such as A row 0 may be used as the paper.

1 is a perspective view showing an outline of an embodiment of a color printer according to the present invention. It is the front view which looked at the carriage from the platen side. It is a figure which expands and shows a nozzle group. It is explanatory drawing which showed the structure of the linear encoder typically. FIG. 5A is a timing chart showing waveforms of two output signals of the linear encoder. FIG. 5B is a timing chart showing waveforms of two output signals of the linear encoder. It is a schematic diagram for demonstrating an edge part detection sensor. It is a figure which shows the structure of the drive signal generation part provided in the nozzle group control unit. It is explanatory drawing of a margin signal. It is a block diagram which shows the control structure of a color printer. It is a block diagram which shows the structure of an image processing unit. It is a flowchart for demonstrating the printing operation of a color printer. It is a flowchart for demonstrating the dot formation process which concerns on printing operation. 13A to 13J are explanatory diagrams for explaining the dot formation processing. 14A and 14B are explanatory diagrams of marginless margins. 15A and 15B are explanatory diagrams of marginless margins. It is a figure which shows the other example of arrangement | positioning of a nozzle group and an edge part detection sensor. It is a figure which shows the other example of arrangement | positioning of a nozzle group and an edge part detection sensor. It is a figure which shows the other example of arrangement | positioning of a nozzle group and an edge part detection sensor.

Explanation of symbols

3 printing section, 5 paper transport section, 12 printed image, 12a to 12h belt-shaped image,
17 linear encoder, 17a light emitting diode, 17b collimator lens,
17c detection processing unit, 17d photodiode, 17e signal processing circuit,
17fA, 17fB comparator,
18 position detection sensor, 19 linear encoder code plate,
20 color printer, 21 CRT, 24 Smap roller,
24a clamping roller, 26 platen, 27 holder, 27a shaft body,
27b guide disk, 28 carriage, 28a, 28b engaging portion,
30 Carriage motor, 31 Carriage motor, 32 Traction belt,
34 guide rail, 341 lower guide rail,
342 Upper guide rail, 35 roll paper holder,
136 print head, 36, 36a-36h nozzle group,
361 end detection sensor, 363 light emitting unit, 365 light receiving unit,
367 Electrical signal measurement unit, 37 Roll paper transport unit,
38, 38a to 38h Image processing unit, 40 drive gear, 41 relay gear,
44a, 44b pulley, 50 buffer memory, 52 image buffer,
54 system controller, 56 RAM, 58 ROM,
61 main scanning drive circuit, 62 sub-scanning drive circuit,
63, 63a to 63h Nozzle group control unit, 90 computers,
91 video drivers, 95 application programs,
97 resolution conversion module, 98 color conversion module,
99 halftone module, 100 rasterizer,
101 user interface display module,
102 UI printer interface module;
103 raster data storage unit, 200 drive signal generation unit, 204 mask circuit,
206 original drive signal generation unit, 207 original drive signal shift correction unit,
224 margin setting part,
COM command, F movement force, LUT color conversion lookup table,
n, n1 to n180 nozzles,
N, Nk, Nc, Nlc, Nm, Nlm, Ny nozzle row,
M Margin without margin, P roll paper, PD print data, SIG margin signal

Claims (9)

A transport mechanism for transporting the medium in the transport direction; and a plurality of nozzle groups arranged along the transport direction, each of the nozzle groups having a plurality of nozzles disposed along the transport direction;
Liquid that performs a discharge operation for discharging liquid from the nozzles and a transport operation for transporting a medium by a predetermined transport amount to the nozzle groups while moving the nozzle group in a crossing direction that intersects the transporting direction. A discharge device,
A plurality of sensors for detecting the position of the end of the medium in the intersecting direction and outputting end position information are provided corresponding to each nozzle group,
A liquid discharge apparatus, wherein at least one of a liquid discharge start position and a discharge stop position is determined for each nozzle group based on end position information of a sensor corresponding to the nozzle group. The liquid ejection apparatus according to claim 1,
The liquid ejecting apparatus according to claim 1, wherein each of the sensors is disposed closest to a nozzle group that the sensor is responsible for. The liquid ejection device according to claim 1 or 2,
Based on end position information of at least two sensors having different arrangement positions with respect to the transport direction, an inclination angle from the transport direction of the medium is calculated,
The liquid ejection apparatus, wherein the calculated value of the tilt angle is further used as end position information to determine at least one of a start position and a stop position at which the liquid is ejected. The liquid ejection apparatus according to claim 3, wherein
The discharge start position and the discharge stop position of each nozzle group are changed based on the calculated value M calculated by the following equation from the inclination angle θ and the length H0 of the nozzle group alone in the transport direction. Liquid ejecting device.
M = H0 × tanθ The liquid ejection apparatus according to any one of claims 1 to 4,
The liquid discharge apparatus, wherein the discharge start position and the discharge stop position are set outside an end of the medium. The liquid ejection apparatus according to any one of claims 1 to 5,
The sensor moves in the cross direction with the nozzle group,
The sensor includes a light emitting unit for emitting light, and a light receiving unit for receiving the light that moves in the crossing direction according to the movement of the light emitting unit in the crossing direction,
Detecting the position of the end of the medium based on a change in the output value of the light receiving unit caused by the light emitted by the light emitting unit moving in the intersecting direction being blocked by the end. Liquid ejecting device. The liquid ejection apparatus according to claim 6, wherein
A liquid ejection apparatus that determines at least one of a liquid ejection start position and a stop position during a current movement operation based on end position information detected during a previous movement operation of the nozzle group . A transport mechanism for transporting the medium in the transport direction; and a plurality of nozzle groups arranged along the transport direction, each of the nozzle groups having a plurality of nozzles disposed along the transport direction;
Liquid that performs a discharge operation for discharging liquid from the nozzles and a transport operation for transporting a medium by a predetermined transport amount to the nozzle groups while moving the nozzle group in a crossing direction that intersects the transporting direction. A discharge device,
A plurality of sensors for detecting the position of the end of the medium in the intersecting direction and outputting end position information are provided corresponding to each nozzle group,
Each sensor is arranged closest to the nozzle group that it is responsible for,
The sensor moves in the crossing direction together with the nozzle group, and the sensor receives a light emitting unit for emitting light and the light moving in the crossing direction according to the movement of the light emitting unit in the crossing direction. A light-receiving part for detecting the output of the light-receiving part when the light emitted by the light-emitting part moving in the intersecting direction is blocked by the end part. Detects the position of
Based on end position information of at least two sensors having different arrangement positions with respect to the transport direction, an inclination angle from the transport direction of the medium is calculated,
Based on the calculated value of the tilt angle and the end position information of the sensor corresponding to the nozzle group, at least one of the liquid discharge start position and the discharge stop position is determined for each nozzle group, and the outside of the end of the medium is determined. The discharge start position and the discharge stop position are set,
A liquid discharge apparatus, wherein at least one of a discharge start position and a discharge stop position at the time of the current movement operation is determined based on end position information detected at the time of the previous movement operation of the nozzle group. A transport mechanism for transporting the medium in the transport direction; and a plurality of nozzle groups arranged along the transport direction, each of the nozzle groups having a plurality of nozzles disposed along the transport direction;
Liquid that performs a discharge operation for discharging liquid from the nozzles and a transport operation for transporting a medium by a predetermined transport amount to the nozzle groups while moving the nozzle group in a crossing direction that intersects the transporting direction. A liquid discharge method using a discharge device,
A plurality of sensors that detect the position of the end of the medium in the intersecting direction and output end position information are used in correspondence with each nozzle group,
A liquid discharge method comprising: determining at least one of a liquid discharge start position and a discharge stop position for each nozzle group based on end position information of a sensor corresponding to the nozzle group.

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