JP6696167B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejection device.

  2. Description of the Related Art There is known a liquid ejecting apparatus that ejects liquid onto an object while conveying the object and reciprocating a liquid ejecting head that ejects liquid in a direction orthogonal to the direction in which the object is conveyed.

  Image forming apparatuses such as a printer, a facsimile, a copying apparatus, and a complex machine of these are known as liquid ejecting apparatuses. As an image forming apparatus, an apparatus including a liquid ejection head is used to convey an ink (recording liquid) as a liquid while conveying a recording medium (hereinafter, also referred to as “paper” but does not limit the material). 2. Description of the Related Art There is known an inkjet type image forming apparatus (inkjet recording apparatus) that adheres to a recording medium and forms an image (recording, printing, printing, and printing are also used as synonyms).

  In the inkjet recording apparatus, an image is formed by ejecting ink while reciprocally moving a carriage having a liquid ejection head in the main scanning direction while sequentially conveying a recording medium in the sub scanning direction. In such a serial type ink jet recording apparatus, there is a problem in that the operation noise of the conveyance mechanism increases as the motor for conveying the recording medium is intermittently driven, resulting in lack of quietness.

  Proposed a serial type inkjet recording device that forms an image diagonally without stopping the conveyance of the recording medium even during printing by reciprocating the liquid ejection head in order to suppress the operating noise and realize excellent quietness Has been done. This is called diagonal printing technology.

  For example, Patent Document 1 discloses a printer intended to reduce operating noise. Further, in order to simplify generation of print data, a conveyance speed of a recording medium and a speed of a carriage have a proportional relationship. It is described to do.

  However, as in Patent Document 1, when the conveyance speed of the recording medium and the speed of the carriage are in a proportional relationship, generation of print data is simple, but the carriage is always stopped at the time of return, and therefore the conveyance is also performed. You have to stop here. Therefore, there is a problem in that the recording medium is intermittently conveyed, and the operating noise cannot be reduced sufficiently.

  Therefore, it is an object of the present invention to provide a liquid ejection device capable of sufficiently reducing operating noise.

In order to achieve such an object, a liquid ejecting apparatus according to the present invention includes a conveying unit that conveys an object, and a moving unit that reciprocates a head that ejects liquid from a nozzle in a direction orthogonal to the conveying direction of the conveying unit. A control unit that controls the liquid to be ejected to the head while the moving unit is moving, and that controls the carrying unit to carry the target object. An acceleration / deceleration region that is accelerating or decelerating, or a constant velocity region in which the moving unit is moving at a constant speed, and in the liquid discharge region of the head, the moving speed of the moving unit and the carrying speed of the carrying unit. Are controlled in proportion to each other, and in a region other than the liquid ejection region of the head, the transport speed of the transport unit is controlled to be a predetermined speed that does not depend on the moving speed of the moving unit, and For each unit, while determining the width for ejecting the liquid in the direction orthogonal to the transport direction, based on the determination result, for each predetermined unit of the object, the reciprocating range of the moving unit, the transport unit At least one of a transport speed and a data processing method for an object to be formed on the object by the liquid is set, and the predetermined unit is a page unit .

  According to the present invention, operating noise can be reduced sufficiently.

FIG. 3 is a schematic configuration diagram showing an image forming apparatus that is an embodiment of a liquid ejection apparatus. FIG. 3 is a plan view illustrating the configuration of the image forming apparatus. FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus. FIG. 9 is an explanatory diagram schematically showing a forward pass and a backward pass of diagonal printing. It is an explanatory view of diagonal printing. FIG. 6 is an explanatory diagram schematically showing a tip portion of a trajectory of a nozzle row in oblique printing. It is a graph explaining the relationship between the main scanning speed and the sub-scanning speed. FIG. 5 is an explanatory diagram of a relationship between a trajectory of nozzles of a liquid ejection head with respect to a sheet and a main scanning speed and a sub scanning speed at that time. FIG. 6 is an explanatory diagram showing a trajectory of a nozzle array when a portion having no image is not scanned in oblique printing.

  Hereinafter, the configuration according to the present invention will be described in detail based on the embodiment shown in FIGS. 1 to 9.

[First Embodiment]
The liquid ejecting apparatus (image forming apparatus 100) according to the present embodiment includes a conveying section (charging conveying belt 12 and the like) that conveys an object (sheet P) and a head (liquid ejecting head) that ejects liquid (ink) from a nozzle. A moving part (carriage 130) for reciprocating 13) in a direction orthogonal to the carrying direction by the carrying part, and a control for causing the head to eject the liquid while the moving part is moving and carrying the object by the carrying part. And a control unit (controller 110) for performing the above, wherein the control unit is an acceleration / deceleration region in which the moving unit is accelerating or decelerating, or a constant speed region in which the moving unit is moving at a constant speed, and In the ejection area, the moving speed of the moving section and the carrying speed of the carrying section are controlled to be proportional to each other, and in areas other than the liquid ejecting area of the head, the carrying speed of the carrying section is set to a predetermined value independent of the moving speed of the moving section. The speed is controlled so as to be (see FIG. 7). In the parentheses, reference numerals and application examples are shown.

  FIG. 1 is a side view illustrating an overall configuration of an image forming apparatus 100 (ink jet recording apparatus) that is an embodiment of a liquid ejection apparatus according to the present invention. FIG. 2 is a plan view illustrating the overall configuration of the image forming apparatus 100.

  The image forming apparatus 100 has a belt driving roller 10, a tension roller 11, and a charging and conveying belt 12 which is an endless belt wound around these two rollers, as a conveying unit for a sheet P which is a recording medium. ing. The charging / conveying belt 12 may be an endless belt in molding or an endless belt formed by connecting both ends. The charging and transporting belt 12 has an insulating layer formed on the surface thereof, and holds electric charges. The charging and transporting belt 12 electrostatically attracts and transports the paper P. The belt drive roller 10 is rotationally driven by a drive system configured by drive means such as a motor.

  The image forming apparatus 100 is equipped with a liquid ejection head 13 as a recording unit that ejects ink onto the sheet P conveyed by the electrification conveyance belt 12 to perform recording, and the liquid ejection head 13, and moves on the sheet P in the main scanning direction. The carriage 130 reciprocates (in a direction perpendicular to the paper surface of FIG. 1).

  As shown in FIG. 2, the image forming apparatus 100 holds the carriage 130 by the guide lot 53 which is horizontally installed on the side plate, and the main scanning motor 140 causes the timing belt 56 passed between the driving pulley 54 and the driven pulley 55 to be passed. Through this, the carriage 130 is moved and scanned in the main scanning direction.

  On the back side of the carriage 130, an encoder scale 51 having slits is provided along the main scanning direction, and the carriage 130 is provided with an encoder sensor 52 for detecting the slits of the encoder scale 51. The encoder scale 51 and the encoder sensor 52 constitute a linear encoder 50 for detecting the position and speed of the carriage 130 in the main scanning direction.

  The liquid ejection head 13 ejects ink from a plurality of nozzles formed on the ink ejection surface. The nozzles form a plurality of nozzle rows arranged in a direction intersecting with the main scanning direction. In the present embodiment, the liquid ejection heads 13y, 13m, 13c, and 13k that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K) (when the colors are not distinguished, " Liquid ejection head 13 ″).

  The image forming apparatus 100 is located between the belt driving roller 10 and the tension roller 11 and is arranged at a position facing the liquid ejection head 13 inside the charging / conveying belt 12, and guides the charging / conveying belt 12 from the inside. It has a transport guide plate 14 as a guide member, and a charging roller 15 that charges an insulating layer that is a surface layer of the charging transport belt 12.

  The image forming apparatus 100 is disposed on the upstream side of the liquid ejection head 13 in the moving direction A of the charging / conveying belt 12 so as to press the belt driving roller 10 via the charging / conveying belt 12, and the sheet P is charged / conveyed. The conveyance roller 16 that is in close contact with the charging roller 12 and the downstream side of the liquid ejection head 13 in the moving direction A of the charging and conveying belt 12 are disposed so as to press the tension roller 11 via the charging and conveying belt 12 and charge the paper P. It has a separation claw 17 that separates it from the conveyor belt 12.

  As shown in FIG. 2, the charging / conveying belt 12 is rotated by the sub-scanning motor 150 rotatably driving the belt driving roller 10 via the driving belt 63 and the timing roller 64. Further, an encoder wheel 61 having a slit is provided on the shaft of the belt driving roller 10, and a transmission type photosensor 62 for detecting the slit of the encoder wheel 61 is provided. The encoder wheel 61 and the photo sensor 62 form a wheel encoder 60.

  The image forming apparatus 100 separates the paper feed tray 18 on which the paper P is stacked, the paper feed roller 19 that feeds the paper P from the paper feed tray 18, and the paper P fed from the paper feed roller 19 into a single sheet and sends it out. It has a separation pad 20 for. The paper feed tray 18, the paper feed roller 19, and the separation pad 20 form a paper feed unit 21.

  The image forming apparatus 100 includes a guide member 29 for guiding the paper P separated by the separation pad 20 and sent, that is, the paper P sent from the paper feeding unit 21 substantially vertically upward, and the charging and conveying belt 12. The sheet P, which is located on the upstream side of the transport roller 16 in the moving direction A and guided by the guide member 29 in a substantially vertical direction, is turned by approximately 90 ° and is transported in a substantially horizontal direction, so that charging is performed. It has a guide member 22 for carrying between the carrying belt 12 and the carrying roller 16.

  The guide member 22 has an arcuate shape with the charging / conveying belt 12 wound around the belt driving roller 10 in order to change the direction of the sheet P guided substantially vertically upward by 90 °. In order to form the conveying path, the surface facing the charging / conveying belt 12 has an arc shape having a radius of curvature larger than that of the charging / conveying belt 12.

  The image forming apparatus 100 has a roller pair 23 located downstream of the liquid ejection head 13 in the direction A for conveying the sheet P separated from the charging conveyance belt 12 by the separation claw 17. Although the roller pair 23 is illustrated as a simple circular cross section in FIG. 1, the spur roller 24 has a star-shaped cross section having a protrusion on the circumference, the roller 25 facing and abutting against the spur roller 24, and the roller pair 23 for feeding. It has a paper discharge tray 26 for stacking the received paper P.

  The spur roller 24 engages with the head-side surface of the paper P on the downstream side of the liquid ejection head 13 in the direction A. The paper P is not only ordinary plain paper, but also OHP sheets, cards, and postcards. In the case of recording on thick paper such as an envelope, it merely assists the feeding of the paper P, and the paper P is caught between the spur roller 24 and the roller 25, that is, the spur roller 24 makes the paper P. Does not define the gap between the paper surface and the liquid ejection head 13.

  The image forming apparatus 100 also includes a manual paper feeding unit 27 that guides the paper P in a direction B substantially horizontally to the image forming unit that performs recording on the recording medium, and a recording medium fed from the manual paper feeding unit. It has a manual feed sensor 28 for detecting the front end and the rear end.

  FIG. 3 is a block diagram showing the overall configuration of the image forming apparatus 100. As shown in FIG. 3, the image forming apparatus 100 includes a controller 110, an operation panel 120, a carriage 130, a main scanning motor 140, a sub scanning motor 150, a linear encoder 50, and a wheel encoder 60.

  The operation panel 120 is a user interface that functions as an operation unit and a display unit for inputting and displaying information necessary for the image forming apparatus 100. The carriage 130 has a liquid ejection head 13 that ejects ink, which is a color developer, on the surface of the paper, and is moved in the main scanning direction during an image forming output operation.

  The main scanning motor 140 is a motor that supplies power for moving the carriage 130 in the main scanning direction. The sub-scanning motor 150 is a motor that supplies power for carrying the paper P, which is a target for forming an image, in the sub-scanning direction.

  The controller 110 is a control unit that controls the operation of the image forming apparatus 100, and as shown in FIG. 3, a CPU (Central Processing Unit) 31, a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, an NVRAM. (Non Volatile RAM) 34, ASIC (Application Specific Integrated Circuit) 35, I / O 36, host I / F 37, DAC (Digital Analogue Converter) 38, head drive unit 39, head control unit 41, main scanning motor drive unit 41, main scanning motor drive unit 41. The sub-scanning motor drive unit 42 is included.

  The CPU 31 is a calculation means and controls the operation of each part of the controller 110. The ROM 32 is a read-only non-volatile storage medium, and stores programs such as firmware. The RAM 33 is a volatile storage medium that can read and write information at high speed, and is used as a work area when the CPU 31 processes information. The NVRAM 34 is a non-volatile storage medium capable of reading and writing information, and stores a control program and control parameters.

  The ASIC 35 is a hardware circuit that executes image processing necessary for image formation and output. The I / O 36 inputs detection pulses from the linear encoder 50 and the wheel encoder 60, and detection signals from other various sensors. The host I / F 37 is an interface for receiving print data from a host device such as a PC (Personal Computer), and an Ethernet (registered trademark) or a USB (Universal Serial Bus) interface is used.

  The DAC 38 converts digital information into an analog signal. The head drive unit 39 inputs the analog signal converted by the DAC 38 into the carriage 130 to drive the liquid ejection head 13. The head controller 40 controls the liquid ejection head 13 based on the image data to be image-formed and output.

  The CPU 31 determines the main scanning position of the carriage 130 based on the output of the linear encoder 50, and also determines the sub scanning position based on the output of the wheel encoder 60, and based on this, determines the main scanning motor drive unit 41 and the sub scanning position. The scanning motor drive unit 42 is controlled.

  The main scanning motor drive unit 41 and the sub-scanning motor drive unit 42 are drive units each having a microcomputer, and drive-control the main scanning motor 140 and the sub-scanning motor 150, respectively, under the control of the CPU 31. That is, the speed of the carriage 130 that reciprocates in the main scanning direction is controlled by driving the main scanning motor 140, and the transportation speed of the paper P transported in the sub scanning direction is controlled by driving the sub scanning motor 150. In the following description, the speed of the carriage 130 that reciprocates in the main scanning direction is also referred to as the main scanning speed, and the conveyance speed of the paper P conveyed in the sub scanning direction is also referred to as the sub scanning speed.

  The main scanning motor drive unit 41 and the sub-scanning motor drive unit 42 may be configured by using the same microcomputer. In this case, the main scanning motor 140 and the sub-scanning motor can be used by one microcomputer. 150 is drive-controlled.

  In the present embodiment, the CPU 31 instructs the main scanning motor drive unit 41 and the sub-scanning motor drive unit 42 about the speed when moving the carriage 130 at a constant speed, and the main scanning motor drive unit 41 and the sub-scanning motor drive unit. Each of the motors 42 drives the main scanning motor 140 and the sub-scanning motor 150 according to a predetermined profile for each constant speed.

  Further, the CPU 31 instructs the main scanning motor drive unit 41 and the sub-scanning motor drive unit 42 about the speeds for moving the carriage 130 at a constant speed and for accelerating and decelerating the main scanning motor drive unit 41 and the sub-scanning motor. The motor drive unit 42 may drive the main scanning motor 140 and the sub-scanning motor 150 based on this.

  Print data from the host side such as an information processing device such as a PC, an image reading device such as an image scanner, and an imaging device such as a digital camera is received by the host I / F 37. The CPU 31 reads out and analyzes print data in the reception buffer included in the host I / F 37, controls the ASIC 35, and executes image processing and data rearrangement processing necessary for image formation output. The image data processed by the ASIC 35 is transferred to the head control unit 40 by the CPU 31.

  The dot pattern data for image formation output may be generated by storing the font data in the ROM 32, for example, or by developing the image data into bit map data by the printer driver on the host side. You may enter it in.

  When the head control unit 40 receives the image data (dot pattern data) corresponding to one row of the liquid ejection head 13, the dot pattern data for one row is serially transferred to the carriage 130 in synchronization with the clock signal. And a latch signal to the carriage 130 at a predetermined timing.

  The DAC 38 reads the pattern data of the drive waveform (head drive signal) stored in the ROM 32, performs D / A conversion to generate a drive waveform of an analog signal, and inputs it to the head drive unit 39. The head drive unit 39 inputs the drive waveform input from the DAC 38 to the carriage 130.

  The carriage 130 includes a shift register that holds a clock signal input from the head controller 40 and serial data that is image data, a latch circuit that latches a resist value of the shift register with a latch signal from the head controller 40, and a latch. It includes a level conversion circuit (level shifter) that changes the level of the output value of the circuit, an analog switch array (switch means) whose ON / OFF is controlled by this level shifter, and the like. Then, the carriage 130 selectively turns on / off the analog switch array to selectively apply a required drive waveform included in the drive waveform input from the head drive unit 39 to the actuator means of the liquid ejection head 13. To drive the liquid ejection head 13.

  Next, diagonal printing by the image forming apparatus 100 will be described. The diagonal printing will be described with reference to FIGS. 4 to 6.

  FIG. 4 shows the loci of the nozzle rows when printing is performed on both the forward and backward paths of the liquid ejection head 13 with parallelogram bands. The left side of the figure shows the trajectory of the nozzle array on the outward path, and the first scan on the outward path is represented by F1 and the second scan is represented by F2. The print area on the paper P is indicated by Pa.

  Further, in FIG. 4, in order to make it easier to understand the trajectory of the reciprocating nozzle array, the trajectory of the nozzle array on the return path is shown shifted to the right. The first scan on the return path is represented by R1, and the second scan is represented by R2.

  FIG. 5 is a diagram schematically showing an actual trajectory of the nozzle row. The forward path is indicated by F, the return path is indicated by R, and the print area on the paper P is indicated by Pa.

  The loci of the nozzle rows shown in FIGS. 4 and 5 are schematically represented by parallelograms. However, in reality, since there is an acceleration / deceleration area of the carriage 130, if the conveyance speed of the paper P is constant, distortion will occur at the left and right ends of the locus with steep angles. That is, the speed of the carriage 130 becomes slower, and if the transport speed of the paper P is constant, the paper P advances further. Further, since the conveyance speed of the paper P is not always constant, how much the distortion occurs depends on the speed ratio between the speed of the carriage 130 and the conveyance speed of the paper P.

  FIG. 6 schematically shows the tip portion of the trajectory of the nozzle row that switches from the return path to the outward path. The carriage 130 stops when changing directions in reciprocating movement. Considering the acceleration / deceleration movement and the stop movement, the actual trajectory is as shown by the solid line in FIG.

  W1 represents distortion caused by deceleration of the carriage 130, and W2 represents distortion caused by acceleration of the carriage 130. S represents the stop time.

  Thus, the locus of the nozzle array becomes a curve when the ratio of the speed of the carriage 130 and the transportation speed of the paper P is not constant. When the speed ratio is constant, it remains a straight line and becomes a perfect parallelogram. As shown in FIG. 6, an inwardly curved locus is drawn when the speed ratio changes in the direction in which the transport speed becomes faster than the speed of the carriage 130.

  That is, the actual movement distance of the carriage 130 is shorter than the distance schematically shown in FIGS. 4 and 5.

  Next, the relationship between the inclination of the locus and the speed ratio of the speed of the carriage 130 and the transport speed of the paper P will be described. The speed of the carriage 130 and the paper P are set so that the leading edge nozzle draws a locus in which the next forward path (or return path) is shifted by one nozzle pitch from the trailing end nozzle Tsu in the transport direction of the previous forward path (or return path). When the speed ratio of the feeding speed of is set, the nozzle locus becomes as shown in FIG. 5, and the entire surface can be printed without a gap.

Here, when the carriage reciprocating time is Tk, the nozzle pitch is Pn, and the number of nozzles is Nn, the nozzle row length Ln can be expressed by the following equation (1).
Ln = (Nn−1) × Pn (1)
Further, the transport speed Vh can be expressed by the following equation (2).
Vh = (Ln + Pn) / Tk (2)

  Like conventional serial printing (hereinafter also referred to as "normal serial printing") in which the paper transport is driven intermittently, after printing the forward path, the paper for the nozzle length is transported and the return path is printed, and the nozzle length In such an operation of conveying the paper, a gap will be generated in the diagonal printing. Therefore, in oblique printing, when printing the entire printing area as shown in FIG. 5, in order to print without a gap, the conveyance distance of the paper P is half the movement distance of the nozzle length even at the maximum.

  In normal serial printing, after the carriage 130 scans and prints on the paper, there is a movement time of the paper transportation, and therefore a waiting time occurs in the carriage 130 depending on the movement distance of the paper transportation.

  When the waiting time is generated in the carriage 130, in order to reduce the waiting time of the carriage 130, printing is not performed during acceleration / deceleration, and the scan width is increased so that the carriage 130 is decelerated during the conveyance time of the paper P. The productivity is improved by accelerating and starting the printing with the carriage 130 at a speed as high as possible at the time of starting the printing.

  On the other hand, in oblique printing, the transport speed of the paper P is proportional to the reciprocating operation time of the carriage 130, and therefore the reciprocating time of the carriage 130 directly leads to productivity. That is, the shorter the round trip time of the carriage 130, the higher the productivity.

  Therefore, when the liquid ejection heads 13 having the same nozzle row (length) are used and the carriage 130 has the same speed and acceleration, the shorter the reciprocating distance of the carriage 130 is, the shorter the reciprocating time of the carriage 130 is, and the productivity is increased. It can be said to rise.

  Further, in the oblique printing technique, if the conveyance speed of the paper P is constant when printing is continued in the acceleration region and the deceleration region of the carriage 130, the locus of the nozzles with respect to the paper P becomes a curve during acceleration / deceleration of the carriage 130. , The image processing becomes complicated because it is not a straight line. On the other hand, if the conveyance speed of the paper P is not made constant and the speed of the carriage 130 is made to be completely proportional, the cutout of the image becomes a parallelogram and does not become complicated, but the carriage 130 always stops at the time of return, so the paper P The conveyance also has to be temporarily stopped, and the conveyance of the paper P becomes an intermittent operation, which reduces the noise suppressing effect.

  Therefore, the controller 110 of the image forming apparatus 100 according to the present embodiment performs the control described below. The details will be described below.

  FIG. 7 is a graph illustrating the relationship between the speed of the carriage 130 (main scanning speed) and the conveyance speed of the paper P (sub scanning speed) in the image forming apparatus 100 according to this embodiment. In FIG. 7, the vertical axis (left) shows the main scanning speed [mm / s], the vertical axis (right) shows the transport speed (sub-scanning speed) [mm / s] of the paper P, and the horizontal axis shows the time [s]. ] Is shown.

  As shown in FIG. 7, in the present embodiment, the speed ratio of the main scanning speed and the sub-scanning speed in the printing area (an example is shown in a1) is constant, but in the non-printing area (an example is shown in a2). The sub-scanning speed is kept constant regardless of the main scanning speed.

  Here, it has been known that the conveyance sound of the sheet P largely depends on the impact sound during the operation when the conveyance of the sheet P is temporarily stopped and then moved again, and the conveyance speed. Therefore, not stopping the paper P and suppressing the maximum speed of the paper P leads to noise reduction.

  Here, when printing is carried out while moving the carriage 130 and the paper P at the same time, in order to print on the paper P without any gap (cover with the trajectory of the nozzle without any gap), the paper P is the nozzle row + 1 nozzle in the reciprocating time of the carriage 130. Just move by the pitch.

  At this time, as shown in FIG. 7, when the speed ratio between the sub-scanning speed and the main scanning speed is not constant in the non-printing area and the conveyance of the paper P is not stopped (the sub-scanning speed is not 0), Since the speed ratio between the sub-scanning speed and the main scanning speed is kept constant and the maximum value of the sub-scanning speed can be suppressed as compared with the case where the conveyance of the paper P is temporarily stopped, it is possible to reduce noise. Becomes

  In the example shown in FIG. 7, the sub-scanning speed is constant in the non-printing area, but the sub-scanning speed is not necessarily constant. For example, the impact noise may be suppressed by making the sub-scanning speed in the non-printing area non-constant so as to be, for example, S-shaped. Further, the maximum value of the sub-scanning speed can be further suppressed by increasing the sub-scanning speed in the non-printing area.

  FIG. 8 is an explanatory diagram of the relationship between the trajectory of the nozzles of the liquid ejection head 13 with respect to the paper P and the main scanning speed and the sub scanning speed at that time in the image forming apparatus 100 according to the present embodiment.

  FIG. 8A is an explanatory diagram of the trajectory of the nozzles on the paper P when the paper P is regarded as fixed. Fa is the trajectory of an arbitrary nozzle in the forward path with respect to the paper P, and Fb is the trajectory with respect to the paper P. 2 shows the trajectory of the nozzle in the return path.

  FIG. 8B is a graph showing the relationship between the position of the carriage 130 in the scanning direction (main scanning direction) and the main scanning speed. Further, FIG. 8C is a graph showing the relationship between the position of the carriage 130 in the scanning direction and the sub-scanning speed. In FIG. 8, A is a print area, B1 is an acceleration area of the carriage 130, B2 is a deceleration area of the carriage 130, and C is a constant speed area (constant speed area) in which the carriage 130 moves at a constant speed. ..

  In FIGS. 8B and 8C, when the horizontal axis is regarded as the “paper position” and the acceleration is constant, in the acceleration region B1 and the deceleration region B2, the curves (quadratic functions) are correct. However, since whether or not the acceleration is constant does not affect the control according to the present embodiment, the horizontal axis is schematically represented by not only “time” but also “paper position” by a straight line.

  In the control of the image forming apparatus 100 according to the present embodiment, as shown in FIG. 8, a part of the acceleration area B1 of the carriage 130 and a part of the deceleration area B2 of the carriage 130 are included in the print area A. Here, an overlapping area of the acceleration area B1 of the carriage 130 and the printing area A is called an acceleration printing area D1, and an overlapping area of the deceleration area B2 of the carriage 130 and the printing area A is called a deceleration printing area D2.

  That is, in the control of the image forming apparatus 100 according to the present embodiment, the printing is started during the acceleration of the carriage 130 and is continued until the deceleration.

  Specifically, the main scanning motor drive unit 41 and the sub-scanning motor drive unit 42 control the main scanning motor 140 and the sub-scanning motor 150, respectively, so that the nozzle locus in the printing area A becomes a straight line and the carriage moves during printing. Regardless of during acceleration / deceleration of 130 or during constant speed, in order to keep the speed ratio with the conveyance speed of the paper P constant, the sub-scanning speed is also accelerated in the accelerated print area D1, and the sub-scanning speed is also in the decelerated print area D2. I try to slow down. Further, outside the print area, the sub-scanning speed is set to a predetermined speed (for example, kept constant) regardless of the main scanning speed.

  The above-described image forming apparatus 100 according to the present embodiment has the highest productivity in oblique printing in which the nozzle trajectory of the liquid ejection head 13 is oblique with respect to the paper P without stopping the conveyance of the paper P during printing. Printing is continued in the acceleration region B1 and the deceleration region B2 of the carriage 130 for the purpose of reducing the width and / or the device width. At this time, in the printing area A (that is, the acceleration printing area D1 and the deceleration printing area D2) which are the acceleration area B1 and the deceleration area B2 of the carriage 130, the speed ratio between the speed of the carriage 130 and the transportation speed of the paper P is set. It is constant. In addition, in the acceleration area B1 and the deceleration area B2 of the carriage 130 and in areas other than the printing area A, the speed ratio is not kept constant, and the conveyance of the paper P is not completely stopped.

  With this, it is possible to maintain the productivity and reduce the width of the apparatus, achieve quietness, and sufficiently reduce the operating noise. Further, it is possible to avoid the image processing from becoming complicated by making the trajectory of the nozzles on the paper P linear.

[Second Embodiment]
Hereinafter, another embodiment of the liquid ejection device according to the present invention will be described. Note that description of the same points as those in the above embodiment will be appropriately omitted.

  As described above, in oblique printing, if the same nozzle row (length) and the same speed and acceleration of the carriage 130 are used, the shorter the carriage 130 reciprocating distance becomes, the shorter the carriage 130 reciprocating time becomes. Goes up.

  However, even if the scan of the carriage 130 is quickly rounded up and returned in a portion where there is no image in the same page, only the overlapping portion is increased and the productivity is not improved. FIG. 9 is an explanatory diagram showing the trajectory of the nozzle row when the carriage 130 is rounded up in the middle of the carriage without changing the carriage speed in the part where there is no image. The outward route is indicated by F and the return route is indicated by R.

  Further, if the conveyance speed is increased to improve productivity, the angle of the trajectory of the nozzle row changes for each scan, which makes image processing very complicated.

  From the above, it is desirable that the scan width be as small as possible according to the image to be printed, but on the other hand, it is desirable that the carriage reciprocating distance (scan width, reciprocating range) be constant within the same page. I can think.

  Therefore, in the second embodiment, the controller 110 determines the width in the main scanning direction for ejecting ink for each page of the paper P (for each predetermined unit of the object), and for each page based on the determination result. And a setting unit that sets at least one of a scan width, a conveyance speed, and a data processing method (image processing method) for an image (formation object) formed on the paper P by the ink.

  The controller 110 first calculates the maximum print width in the same page, and changes the scan width, the conveyance speed, and the image cutting method in page units based on the calculated maximum print width.

  As a result, when the width of the image to be printed is narrow on a page-by-page basis, the productivity can be improved without complicating the image processing.

  In addition, in the second embodiment, when the carriage 130 reciprocates continuously for a very short distance, the vibration during acceleration / deceleration is not canceled and the next acceleration / deceleration operation starts, and the residual vibration is amplified. As a result, image distortion may occur.

  Therefore, it is preferable that a lower limit value is set in advance for the scan width calculated and set by the controller 110, and when a value less than the lower limit value is calculated, the set value is set to the lower limit value.

  As a result, it is possible to prevent the carriage 130 from reciprocating over a very short distance, and prevent deterioration of image quality such as image distortion.

[Third Embodiment]
In normal serial printing, with respect to an abnormal operation such as opening a cover during printing, after completing printing for the scanning operation during printing, the carriage 130 is stopped, the abnormal operation is resolved, and printing can be restored. It is known to resume printing later.

  When such error processing at the time of abnormal operation is performed by oblique printing, the paper P continues to move in synchronization with the operation of the carriage 130. Therefore, even if the carriage 130 stops, the conveyance of the paper P is stopped. If the control is not performed, it is necessary to adjust the carry amount of the paper P.

  Therefore, in the present embodiment, the controller 110 determines interruption and restart of the printing operation (ejection operation), and when the interruption of printing is determined, the printing operation and the paper P for one scan of the carriage 130 are determined. Stop after continuing the transportation of. Then, the restart of the printing operation is restarted after the paper P is carried by the difference distance compared to the carrying distance in the case where the printing operation is not interrupted before the restart of the printing operation is judged and restarted. It is what makes them.

  That is, after the printing of the carriage 130 is completed, the conveyance is stopped and put in a standby state. However, since the conveyance of the paper P should continue to operate normally, the conveyance of the paper P precedes the carriage 130 before the printing is resumed. The carriage 130 is operated to delay the start of the operation of the carriage 130 by a distance required to move the paper P.

  This makes it possible to restart printing without wasting the paper P even during abnormal operation.

  It should be noted that the adjustment of the carry amount in the present embodiment is not limited to the case where the printing is restarted, and may be made when the carry is stopped.

  Further, depending on the reason why the printing operation is interrupted, it may be preferable to stop the conveyance of the paper P as soon as possible. In this case, the conveyance is stopped at the same time as the interruption of the printing operation, and the reason for the interruption of the printing operation is eliminated. It is preferable to convey.

  Even when the carriage 130 is vibrated at the start of the operation, similarly, when the printing is restarted, the conveyance of the paper P is performed in advance so that the conveyance operation vibrates at the start of the operation of the carriage 130. It is possible to avoid being affected by.

[Fourth Embodiment]
The diagonal printing method by the image forming apparatus 100 according to the present embodiment is realized by changing the speed control of the carriage 130, the conveyance control of the paper P, and the image processing method, unlike the normal serial printing.

  Therefore, it is preferable that the image forming apparatus 100 is capable of performing normal serial printing, and is capable of selecting either diagonal printing or normal serial printing depending on the situation.

  Further, in oblique printing, if the speed is lowered overall while the ratio of the speed of the carriage 130 and the conveyance speed of the paper P is kept constant, the productivity will be reduced by that amount, but further noise reduction will be achieved. Can be realized.

  Therefore, it is preferable that the quietness level be settable and selectable by the user. The user can select a desired level in consideration of the balance between quietness and productivity. For example, when it is desired to avoid noise, by placing emphasis on silent noise and setting the mode to reduce productivity, it becomes possible to meet the user's request.

  At this time, the quietness can be easily predicted based on the transport speed, but the productivity changes depending on the data to be printed and the like. Therefore, it is preferable that the controller 110 estimates the productivity from the maximum image width and the maximum image length and displays the obtained estimated value (estimated formation time) on the operation panel 120. With this, the user can know the productivity according to the print content, so that the silent level can be selected in consideration of the estimated value of the productivity.

  The selection of the printing mode (oblique printing / normal serial printing) and the selection of the silent level are notified to the CPU 31 of the operation contents, for example, when the user operates the operation panel 120.

  The above-described embodiment is a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

  For example, in the present application, the “liquid ejecting apparatus” is an apparatus that includes a liquid ejecting head and drives the liquid ejecting head to eject the liquid. The liquid ejecting apparatus includes not only an apparatus capable of ejecting a liquid to which a liquid can be attached, but also an apparatus ejecting the liquid toward the air or into the liquid.

  The “liquid ejecting device” can also include means for feeding, carrying, and discharging paper to which liquid can be attached, as well as a pretreatment device and a posttreatment device.

  For example, as the “liquid ejecting device”, an image forming device that is a device that ejects ink to form an image on a sheet, or a powder in which layers of powder are formed to form a three-dimensional object (three-dimensional object) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid to the body layer.

  Further, the “liquid ejecting device” is not limited to a device in which a significant image such as characters and figures is visualized by the ejected liquid. For example, it also includes ones that form patterns and the like that have no meaning per se, and ones that form a three-dimensional image.

  The above-mentioned "liquid can be adhered" means a liquid to which a liquid can be at least temporarily adhered, which is adhered and fixed, and which is adhered and permeated. Specific examples include recording media such as paper, recording paper, recording paper, film and cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, inspection cells and other media. Yes, and unless otherwise specified, includes anything to which liquid adheres.

  The material of the above-mentioned "liquid can be adhered" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc. as long as the liquid can be adhered even temporarily.

  The “liquid” may be any one that has a viscosity and surface tension that can be ejected from the head, and is not particularly limited, but it is one that has a viscosity of 30 mPa · s or less at room temperature and atmospheric pressure, or by heating and cooling. Preferably. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins and calcium. , Solutions, suspensions, emulsions, etc. containing edible materials such as natural pigments, etc., such as ink-jet inks, surface treatment solutions, components of electronic devices and light-emitting devices, and formation of electronic circuit resist patterns. It can be used for applications such as a working fluid and a three-dimensional modeling material fluid.

  In addition, as the "liquid ejecting device", a treatment liquid application device that ejects the treatment liquid onto the paper in order to apply the treatment liquid onto the surface of the paper for the purpose of modifying the surface of the paper, a raw material solution, and the like. There is an injection granulating device which sprays a composition liquid dispersed therein through a nozzle to granulate fine particles of a raw material.

10 Belt Drive Roller 11 Tension Roller 12 Charging and Conveying Belt 13 Liquid Ejecting Head 14 Conveying Guide Plate 15 Charging Roller 16 Conveying Roller 17 Separation Claw 18 Paper Feed Tray 19 Paper Feeding Roller 20 Separation Pad 21 Paper Feeding Unit 22 Guide Member 23 Roller Pair 24 Spur roller 25 Roller 26 Paper ejection tray 27 Manual paper feed section 28 Manual sensor 29 Guide member 31 CPU
32 ROM
33 RAM
34 NVRAM
35 ASIC
36 I / O
37 Host I / F
38 DAC
39 head drive unit 40 head control unit 41 main scanning motor drive unit 42 sub-scanning motor drive unit 50 linear encoder 51 encoder scale 52 encoder sensor 53 guide lot 54 drive pulley 55 driven pulley 56 timing belt 60 wheel encoder 61 encoder wheel 62 transmissive type Photo sensor 63 Drive belt 64 Timing roller 100 Image forming apparatus 110 Controller 120 Operation panel 130 Carriage 140 Main scanning motor 150 Sub scanning motor P Paper

JP, 2004-338215, A

Claims (6)

A transport unit for transporting an object,
A moving unit that reciprocates a head that discharges liquid from a nozzle in a direction orthogonal to the carrying direction of the carrying unit;
A control unit that controls the liquid to be ejected to the head while the moving unit is moving, and that controls the carrying unit to carry the object.
The control unit is
An acceleration / deceleration region in which the moving unit is accelerating or decelerating, or a constant velocity region in which the moving unit is moving at a constant speed,
In the liquid discharge area of the head, while controlling the moving speed of the moving unit and the carrying speed of the carrying unit to be proportional,
In a region other than the liquid ejection region of the head, the transport speed of the transport unit is controlled to be a predetermined speed that does not depend on the moving speed of the moving unit ,
For each predetermined unit of the object, while determining the width of ejecting the liquid in the direction orthogonal to the transport direction,
Based on the determination result, for each predetermined unit of the target object, the reciprocating range of the moving unit, the transport speed of the transport unit, the data processing method for the object to be formed on the target object by the liquid, Set at least one,
The liquid ejecting apparatus is characterized in that the predetermined unit is a page unit . The control unit is
Set the lower limit of the reciprocating range of the moving unit,
The determination reciprocating movement range of the moving unit based on a result is, if less than the lower limits, the liquid ejecting apparatus according to claim 1, characterized in that to set the lower limit value as a reciprocating movement range of the head . The control unit is
While determining whether to suspend or restart the ejection operation from the head,
When it is determined that the discharging operation is interrupted, for one movement of the moving unit, the discharging operation and the transportation of the object are stopped and then stopped.
When determining the resumption of the ejection operation, the distance portion of the case there is no interruption of the discharge operation, the after conveying the said object, in claim 1 or 2, characterized in that to resume the discharge operation The liquid ejection device described. The control unit is
When controlling the moving speed of the moving unit and the carrying speed of the carrying unit to be proportional, the moving speed of the moving unit and the carrying speed of the carrying unit are selected from a plurality of combinations. liquid ejecting apparatus according to claim 1, wherein up to 3. The control unit is
For each combination of the plurality of combinations, based on the data about the formation subject to be formed into the object by the liquid, the claim 4, characterized in that to display the estimated forming time of the formation subject Liquid ejector.   The liquid ejecting apparatus according to claim 1, wherein the predetermined speed is a constant speed.